query: Macrolides have no protective effect against myocardial infarction.

positive: Antibiotics and risk of subsequent first-time acute myocardial infarction. CONTEXT Increasing evidence supports the hypothesis of a causal association between certain bacterial infections and increased risk of developing acute myocardial infarction. If such a causal association exists, subjects who used antibiotics active against the bacteria, regardless of indication, might be at lower risk of developing acute myocardial infarction than nonusers. OBJECTIVE To determine whether previous use of antibiotics decreases the risk of developing a first-time acute myocardial infarction. DESIGN Population-based case-control analysis. SETTING The United Kingdom-based General Practice Research Database comprising 350 general practices. PATIENTS A total of 3315 case patients aged 75 years or younger with a diagnosis of first-time acute myocardial infarction between 1992 and 1997 and 13139 controls without myocardial infarction matched to cases for age, sex, general practice attended, and calendar time. MAIN OUTCOME MEASURES Use of antibiotics among those who did or did not have a first-time acute myocardial infarction. RESULTS Cases were significantly less likely to have used tetracycline antibiotics (adjusted odds ratio [OR], 0.70; 95% confidence interval [CI], 0.55-0.90) or quinolones (adjusted OR, 0.45; 95% CI, 0.21-0.95). No effect was found for previous use of macrolides (primarily erythromycin), sulfonamides, penicillins, or cephalosporins. CONCLUSIONS The findings from this large case-control analysis provide further, albeit indirect, evidence for an association between bacterial infections with organisms susceptible to tetracycline or quinolone antibiotics and the risk of acute myocardial infarction. These results of preliminary nature should stimulate more research to further explore the role of infections in the etiology of acute myocardial infarction.

negative: Nitrite protects against morbidity and mortality associated with TNF- or LPS-induced shock in a soluble guanylate cyclase–dependent manner Nitrite (NO(2)(-)), previously viewed as a physiologically inert metabolite and biomarker of the endogenous vasodilator NO, was recently identified as an important biological NO reservoir in vasculature and tissues, where it contributes to hypoxic signaling, vasodilation, and cytoprotection after ischemia-reperfusion injury. Reduction of nitrite to NO may occur enzymatically at low pH and oxygen tension by deoxyhemoglobin, deoxymyoglobin, xanthine oxidase, mitochondrial complexes, or NO synthase (NOS). We show that nitrite treatment, in sharp contrast with the worsening effect of NOS inhibition, significantly attenuates hypothermia, mitochondrial damage, oxidative stress and dysfunction, tissue infarction, and mortality in a mouse shock model induced by a lethal tumor necrosis factor challenge. Mechanistically, nitrite-dependent protection was not associated with inhibition of mitochondrial complex I activity, as previously demonstrated for ischemia-reperfusion, but was largely abolished in mice deficient for the soluble guanylate cyclase (sGC) alpha1 subunit, one of the principal intracellular NO receptors and signal transducers in the cardiovasculature. Nitrite could also provide protection against toxicity induced by Gram-negative lipopolysaccharide, although higher doses were required. In conclusion, we show that nitrite can protect against toxicity in shock via sGC-dependent signaling, which may include hypoxic vasodilation necessary to maintain microcirculation and organ function, and cardioprotection.

negative: Caveolin-1 deletion exacerbates cardiac interstitial fibrosis by promoting M2 macrophage activation in mice after myocardial infarction. Adverse remodeling following myocardial infarction (MI) leading to heart failure is driven by an imbalanced resolution of inflammation. The macrophage cell is an important control of post-MI inflammation, as macrophage subtypes secrete mediators to either promote inflammation and extend injury (M1 phenotype) or suppress inflammation and promote scar formation (M2 phenotype). We have previously shown that the absence of caveolin-1 (Cav1), a membrane scaffolding protein, is associated with adverse cardiac remodeling in mice, but the mechanisms responsible remain to be elucidated. We explore here the role of Cav1 in the activation of macrophages using wild type C57BL6/J (WT) and Cav1(tm1Mls/J) (Cav1(-/-)) mice. By echocardiography, cardiac function was comparable between WT and Cav1(-/-) mice at 3days post-MI. In the absence of Cav1, there were a surprisingly higher percentage of M2 macrophages (arginase-1 positive) detected in the infarcted zone. Conversely, restoring Cav1 function after MI in WT mice by adding back the Cav1 scaffolding domain reduced the M2 activation profile. Further, adoptive transfer of Cav1 null macrophages into WT mice on d3 post-MI exacerbated adverse cardiac remodeling at d14 post-MI. In vitro studies revealed that Cav1 null macrophages had a more pronounced M2 profile activation in response to IL-4 stimulation. In conclusion, Cav1 deletion promotes an array of maladaptive repair processes after MI, including increased TGF-β signaling, increased M2 macrophage infiltration and dysregulation of the M1/M2 balance. Our data also suggest that cardiac remodeling can be improved by therapeutic intervention regulating Cav1 function during the inflammatory response phase.

negative: Interleukin-33 prevents apoptosis and improves survival after experimental myocardial infarction through ST2 signaling. BACKGROUND ST2 is an interleukin (IL)-1 receptor family member with membrane-bound (ST2L) and soluble (sST2) isoforms, and sST2 is a biomarker for poor outcome in patients with myocardial infarction (MI). IL-33, the recently discovered ligand for ST2, activates nuclear factor kappaB and thus may regulate apoptotic cell death. We tested the hypothesis that IL-33 is cardioprotective after MI through ST2 signaling. METHODS AND RESULTS IL-33 protected cultured cardiomyocytes from hypoxia-induced apoptosis, and this cardioprotection was partially inhibited by sST2. IL-33 induced expression of the antiapoptotic factors XIAP, cIAP1, and survivin. To define the cardioprotective role of IL-33 in vivo, we performed a blinded and randomized study of ischemia/reperfusion in rats. IL-33 reduced cardiomyocyte apoptosis, suppressed caspase-3 activity, and increased expression of IAP family member proteins. IL-33 decreased both infarct and fibrosis volumes at 15 days; furthermore, both echocardiographic and hemodynamic studies revealed that IL-33 improved ventricular function. To determine whether cardioprotection by IL-33 is mediated through ST2 signaling, a randomized and blinded study of ST2(-/-) versus wild-type littermate mice was performed in 98 mice subjected to MI. At 4 weeks after MI, IL-33 reduced ventricular dilation and improved contractile function in wild-type mice but not in ST2(-/-) mice. Finally, IL-33 improved survival after MI in wild-type but not in ST2(-/-) mice. CONCLUSIONS IL-33 prevents cardiomyocyte apoptosis and improves cardiac function and survival after MI through ST2 signaling.

negative: Fingolimod provides long-term protection in rodent models of cerebral ischemia. OBJECTIVE The sphingosine-1-phosphate (S1P) receptor agonist fingolimod (FTY720), that has shown efficacy in advanced multiple sclerosis clinical trials, decreases reperfusion injury in heart, liver, and kidney. We therefore tested the therapeutic effects of fingolimod in several rodent models of focal cerebral ischemia. To assess the translational significance of these findings, we asked whether fingolimod improved long-term behavioral outcomes, whether delayed treatment was still effective, and whether neuroprotection can be obtained in a second species. METHODS We used rodent models of middle cerebral artery occlusion and cell-culture models of neurotoxicity and inflammation to examine the therapeutic potential and mechanisms of neuroprotection by fingolimod. RESULTS In a transient mouse model, fingolimod reduced infarct size, neurological deficit, edema, and the number of dying cells in the core and periinfarct area. Neuroprotection was accompanied by decreased inflammation, as fingolimod-treated mice had fewer activated neutrophils, microglia/macrophages, and intercellular adhesion molecule-1 (ICAM-1)-positive blood vessels. Fingolimod-treated mice showed a smaller infarct and performed better in behavioral tests up to 15 days after ischemia. Reduced infarct was observed in a permanent model even when mice were treated 4 hours after ischemic onset. Fingolimod also decreased infarct size in a rat model of focal ischemia. Fingolimod did not protect primary neurons against glutamate excitotoxicity or hydrogen peroxide, but decreased ICAM-1 expression in brain endothelial cells stimulated by tumor necrosis factor alpha. INTERPRETATION These findings suggest that anti-inflammatory mechanisms, and possibly vasculoprotection, rather than direct effects on neurons, underlie the beneficial effects of fingolimod after stroke. S1P receptors are a highly promising target in stroke treatment.

negative: The Function and Therapeutic Potential of Long Non-coding RNAs in Cardiovascular Development and Disease The popularization of genome-wide analyses and RNA sequencing led to the discovery that a large part of the human genome, while effectively transcribed, does not encode proteins. Long non-coding RNAs have emerged as critical regulators of gene expression in both normal and disease states. Studies of long non-coding RNAs expressed in the heart, in combination with gene association studies, revealed that these molecules are regulated during cardiovascular development and disease. Some long non-coding RNAs have been functionally implicated in cardiac pathophysiology and constitute potential therapeutic targets. Here, we review the current knowledge of the function of long non-coding RNAs in the cardiovascular system, with an emphasis on cardiovascular development and biology, focusing on hypertension, coronary artery disease, myocardial infarction, ischemia, and heart failure. We discuss potential therapeutic implications and the challenges of long non-coding RNA research, with directions for future research and translational focus.

negative: Relative roles of direct regeneration versus paracrine effects of human cardiosphere-derived cells transplanted into infarcted mice. RATIONALE Multiple biological mechanisms contribute to the efficacy of cardiac cell therapy. Most prominent among these are direct heart muscle and blood vessel regeneration from transplanted cells, as opposed to paracrine enhancement of tissue preservation and/or recruitment of endogenous repair. OBJECTIVE Human cardiac progenitor cells, cultured as cardiospheres (CSps) or as CSp-derived cells (CDCs), have been shown to be capable of direct cardiac regeneration in vivo. Here we characterized paracrine effects in CDC transplantation and investigated their relative importance versus direct differentiation of surviving transplanted cells. METHODS AND RESULTS In vitro, many growth factors were found in media conditioned by human adult CSps and CDCs; CDC-conditioned media exerted antiapoptotic effects on neonatal rat ventricular myocytes, and proangiogenic effects on human umbilical vein endothelial cells. In vivo, human CDCs secreted vascular endothelial growth factor, hepatocyte growth factor, and insulin-like growth factor 1 when transplanted into the same SCID mouse model of acute myocardial infarction where they were previously shown to improve function and to produce tissue regeneration. Injection of CDCs in the peri-infarct zone increased the expression of Akt, decreased apoptotic rate and caspase 3 level, and increased capillary density, indicating overall higher tissue resilience. Based on the number of human-specific cells relative to overall increases in capillary density and myocardial viability, direct differentiation quantitatively accounted for 20% to 50% of the observed effects. CONCLUSIONS Together with their spontaneous commitment to cardiac and angiogenic differentiation, transplanted CDCs serve as "role models," recruiting endogenous regeneration and improving tissue resistance to ischemic stress. The contribution of the role model effect rivals or exceeds that of direct regeneration.

negative: Effects of Abciximab on the architecture of platelet-rich clots in patients with acute myocardial infarction undergoing primary coronary intervention. BACKGROUND Abciximab plus aspirin improves the TIMI 3 flow rate of the infarct-related artery in patients treated with either percutaneous coronary intervention or thrombolysis. The present study investigated whether the reperfusion efficacy of abciximab relates to modifications of clot architecture in patients admitted for acute myocardial infarction (AMI). METHODS AND RESULTS A total of 23 AMI patients in the Abciximab before Direct angioplasty and stenting in Myocardial Infarction Regarding Acute and Long term follow-up (ADMIRAL) trial received, in a double-blind fashion, either abciximab (n=13) or placebo (n=10) before primary stenting. Viscoelastic (G' in dyne/cm(2)) and morphological (mean platelet aggregate surface area [SAG] in micrometer(2)) indexes of ex vivo platelet-rich clots (PRC) were assessed in a double-blind fashion before and after the bolus administration of abciximab or placebo. G' and SAG reflect the mechanical and morphological impact of activated platelets on the PRC fibrin network, respectively. Abciximab administration reduced G' by 63% (P=0.0001) and SAG by 65% (P=0.0007), and no effect was seen in the placebo group. These abciximab-related changes increased fibrin exposure as a consequence of the platelet-aggregate surface reduction and may have improved endogenous fibrinolysis. These effects were identified in all patients, independent of previous heparin administration. CONCLUSIONS Abciximab dramatically reduces platelet aggregate size and increases the fibrin accessibility of ex vivo PRC in AMI patients. These modifications could participate in the better coronary artery patency observed with abciximab.

negative: Secreted Frizzled-related Protein 5 Diminishes Cardiac Inflammation and Protects the Heart from Ischemia/Reperfusion Injury. Wnt signaling has diverse actions in cardiovascular development and disease processes. Secreted frizzled-related protein 5 (Sfrp5) has been shown to function as an extracellular inhibitor of non-canonical Wnt signaling that is expressed at relatively high levels in white adipose tissue. The aim of this study was to investigate the role of Sfrp5 in the heart under ischemic stress. Sfrp5 KO and WT mice were subjected to ischemia/reperfusion (I/R). Although Sfrp5-KO mice exhibited no detectable phenotype when compared with WT control at baseline, they displayed larger infarct sizes, enhanced cardiac myocyte apoptosis, and diminished cardiac function following I/R. The ischemic lesions of Sfrp5-KO mice had greater infiltration of Wnt5a-positive macrophages and greater inflammatory cytokine and chemokine gene expression when compared with WT mice. In bone marrow-derived macrophages, Wnt5a promoted JNK activation and increased inflammatory gene expression, whereas treatment with Sfrp5 blocked these effects. These results indicate that Sfrp5 functions to antagonize inflammatory responses after I/R in the heart, possibly through a mechanism involving non-canonical Wnt5a/JNK signaling.

negative: Impact of diabetes on long-term prognosis in patients with unstable angina and non-Q-wave myocardial infarction: results of the OASIS (Organization to Assess Strategies for Ischemic Syndromes) Registry. BACKGROUND Although unstable coronary artery disease is the most common reason for admission to a coronary care unit, the long-term prognosis of patients with this diagnosis is unknown. This is particularly true for patients with diabetes mellitus, who are known to have a high morbidity and mortality after an acute myocardial infarction. METHODS AND RESULTS Prospectively collected data from 6 different countries in the Organization to Assess Strategies for Ischemic Syndromes (OASIS) registry were analyzed to determine the 2-year prognosis of diabetic and nondiabetic patients who were hospitalized with unstable angina or non-Q-wave myocardial infarction. Overall, 1718 of 8013 registry patients (21%) had diabetes. Diabetic patients had a higher rate of coronary bypass surgery than nondiabetic patients (23% versus 20%, P:<0.001) but had similar rates of catheterization and angioplasty. Diabetes independently predicted mortality (relative risk [RR], 1.57; 95% CI, 1.38 to 1.81; P:<0.001), as well as cardiovascular death, new myocardial infarction, stroke, and new congestive heart failure. Moreover, compared with their nondiabetic counterparts, women had a significantly higher risk than men (RR, 1.98; 95% CI, 1.60 to 2.44; and RR, 1.28; 95% CI, 1.06 to 1.56, respectively). Interestingly, diabetic patients without prior cardiovascular disease had the same event rates for all outcomes as nondiabetic patients with previous vascular disease. CONCLUSIONS Hospitalization for unstable angina or non-Q-wave myocardial infarction predicts a high 2-year morbidity and mortality; this is especially evident for patients with diabetes. Diabetic patients with no previous cardiovascular disease have the same long-term morbidity and mortality as nondiabetic patients with established cardiovascular disease after hospitalization for unstable coronary artery disease.

negative: In-hospital switching between adenosine diphosphate receptor inhibitors in patients with acute myocardial infarction treated with percutaneous coronary intervention: Insights into contemporary practice from the TRANSLATE-ACS study. AIMS While randomized clinical trials have compared clopidogrel with higher potency adenosine diphosphate (ADP) receptor inhibitors among patients with acute myocardial infarction, little is known about the frequency, effectiveness and safety of switching between ADP receptor inhibitors in routine clinical practice. METHODS AND RESULTS We studied 11,999 myocardial infarction patients treated with percutaneous coronary intervention at 230 hospitals from April 2010 to October 2012 in the TRANSLATE-ACS study. Multivariable Cox regression was used to compare six-month post-discharge risks of major adverse cardiovascular events (MACE: death, myocardial infarction, stroke, or unplanned revascularization) and Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO)-defined bleeding between in-hospital ADP receptor inhibitor switching versus continuation of the initially selected therapy. Among 8715 patients treated initially with clopidogrel, 994 (11.4%) were switched to prasugrel or ticagrelor; switching occurred primarily after percutaneous coronary intervention (60.9%) and at the time of hospital discharge (26.7%). Among 3284 patients treated initially with prasugrel or ticagrelor, 448 (13.6%) were switched to clopidogrel; 48.2% of switches occurred after percutaneous coronary intervention and 48.0% at hospital discharge. Switching to prasugrel or ticagrelor was not associated with increased bleeding when compared with continuation on clopidogrel (2.7% vs. 3.3%, adjusted hazard ratio 0.96, 95% confidence interval 0.64-1.42, p=0.82). Switching from prasugrel or ticagrelor to clopidogrel was not associated with increased MACE (8.9% vs. 7.7%, adjusted hazard ratio 1.06, 95% confidence interval 0.75-1.49, p=0.76) when compared with continuation on the higher potency agent. CONCLUSIONS In-hospital ADP receptor inhibitor switching occurs in more than one in 10 myocardial infarction patients in contemporary practice. In this observational study, ADP receptor inhibitor switching does not appear to be significantly associated with increased hazard of MACE or bleeding.

negative: Association between serum corin levels and risk of acute myocardial infarction. BACKGROUND Accumulating evidence has indicated that corin plays critical roles in regulating salt-water balance, blood pressure and cardiac function by activating natriuretic peptides. The present case-control study was designed to evaluate the association of serum soluble corin with acute myocardial infarction (AMI). METHODS We enrolled 856 consecutive AMI patients and 856 control subjects and explored the possible relation between serum corin levels and AMI risk using logistic regression model. RESULTS Patients with AMI had higher BMI, were less physically active, and were more likely to have histories of hypertension, diabetes, hyperlipidemia and smoking compared with the controls. Serum levels of corin were remarkably reduced in AMI patients (825±263pg/ml) compared with those in healthy controls (1246±425pg/ml). Odds ratios of ST elevation (STEMI) and non-ST elevation myocardial infarction (NSTEMI) were significantly decreased with the increasing levels of serum corin in both men and women (P for trend, <0.001) after adjustment for body mass index, hypertension, diabetes, hyperlipidemia, smoking, and physical activity. CONCLUSIONS Our study demonstrates that serum levels of corin are significantly decreased in AMI patients, and it is inversely associated with the incidences of STEMI and NSTEMI in both men and women.

negative: Macrophages in the Pathogenesis of Atherosclerosis In atherosclerosis, the accumulation of apolipoprotein B-lipoproteins in the matrix beneath the endothelial cell layer of blood vessels leads to the recruitment of monocytes, the cells of the immune system that give rise to macrophages and dendritic cells. Macrophages derived from these recruited monocytes participate in a maladaptive, nonresolving inflammatory response that expands the subendothelial layer due to the accumulation of cells, lipid, and matrix. Some lesions subsequently form a necrotic core, triggering acute thrombotic vascular disease, including myocardial infarction, stroke, and sudden cardiac death. This Review discusses the central roles of macrophages in each of these stages of disease pathogenesis.

negative: Diagnostic accuracy of single baseline measurement of Elecsys Troponin T high-sensitive assay for diagnosis of acute myocardial infarction in emergency department: systematic review and meta-analysis OBJECTIVE To obtain summary estimates of the accuracy of a single baseline measurement of the Elecsys Troponin T high-sensitive assay (Roche Diagnostics) for the diagnosis of acute myocardial infarction in patients presenting to the emergency department. DESIGN Systematic review and meta-analysis of diagnostic test accuracy studies. DATA SOURCES Medline, Embase, and other relevant electronic databases were searched for papers published between January 2006 and December 2013. STUDY SELECTION Studies were included if they evaluated the diagnostic accuracy of a single baseline measurement of Elecsys Troponin T high-sensitive assay for the diagnosis of acute myocardial infarction in patients presenting to the emergency department with suspected acute coronary syndrome. STUDY APPRAISAL AND DATA SYNTHESIS The first author screened all titles and abstracts identified through the searches and selected all potentially relevant papers. The screening of the full texts, the data extraction, and the methodological quality assessment, using the adapted QUADAS-2 tool, were conducted independently by two reviewers with disagreements being resolved through discussion or arbitration. If appropriate, meta-analysis was conducted using the hierarchical bivariate model. RESULTS Twenty three studies reported the performance of the evaluated assay at presentation. The results for 14 ng/L and 3-5 ng/L cut-off values were pooled separately. At 14 ng/L (20 papers), the summary sensitivity was 89.5% (95% confidence interval 86.3% to 92.1%) and the summary specificity was 77.1% (68.7% to 83.7%). At 3-5 ng/L (six papers), the summary sensitivity was 97.4% (94.9% to 98.7%) and the summary specificity was 42.4% (31.2% to 54.5%). This means that if 21 of 100 consecutive patients have the target condition (21%, the median prevalence across the studies), 2 (95% confidence interval 2 to 3) of 21 patients with acute myocardial infarction will be missed (false negatives) if 14 ng/L is used as a cut-off value and 18 (13 to 25) of 79 patients without acute myocardial infarction will test positive (false positives). If the 3-5 ng/L cut-off value is used, <1 (0 to 1) patient with acute myocardial infarction will be missed and 46 (36 to 54) patients without acute myocardial infarction will test positive. CONCLUSIONS The results indicate that a single baseline measurement of the Elecsys Troponin T high-sensitive assay could be used to rule out acute myocardial infarction if lower cut-off values such as 3 ng/L or 5 ng/L are used. However, this method should be part of a comprehensive triage strategy and may not be appropriate for patients who present less than three hours after symptom onset. Care must also be exercised because of the higher imprecision of the evaluated assay and the greater effect of lot-to-lot reagent variation at low troponin concentrations. SYSTEMATIC REVIEW REGISTRATION PROSPERO registration number CRD42013003926.

negative: Cardiac glycosides inhibit TNF-α/NF-κB signaling by blocking recruitment of TNF receptor-associated death domain to the TNF receptor Digitoxin and structurally related cardiac glycoside drugs potently block activation of the TNF-α/NF-κB signaling pathway. We have hypothesized that the mechanism might be discovered by searching systematically for selective inhibitory action through the entire pathway. We report that the common action of these drugs is to block the TNF-α-dependent binding of TNF receptor 1 to TNF receptor-associated death domain. This drug action can be observed with native cells, such as HeLa, and reconstituted systems prepared in HEK293 cells. All other antiinflammatory effects of digitoxin on NF-κB and c-Jun N-terminal kinase pathways appear to follow from the blockade of this initial upstream signaling event.

negative: How much alcohol and how often? Population based case-control study of alcohol consumption and risk of a major coronary event. OBJECTIVE To quantify the effects of quantity and frequency of alcohol consumption on risk of acute myocardial infarction and coronary death. DESIGN Case-control study. SETTING Lower Hunter region of New South Wales, Australia, 1983-94. SUBJECTS Men and women aged 35-69 years. MAIN OUTCOME MEASURE Acute myocardial infarction or coronary death. RESULTS Alcohol consumption patterns were compared between 11,511 cases of acute myocardial infarction or coronary death and 6077 controls randomly selected from the same study population. After adjusting for the effects of age, smoking, and medical history, men and women who consumed one or two drinks of alcohol on five or six days a week had a reduction in risk of a major coronary event compared with men and women who were non-drinkers (odds ratios: men 0.31 (95% confidence interval 0.22 to 0.45); women 0.33 (0.18 to 0.59)). A similar reduction in risk was found after excluding non-drinkers who were formerly moderate to heavy drinkers. An acute protective effect of alcohol consumption was also found for regular drinkers who consumed one or two drinks in the 24 hours preceding the onset of symptoms (odds ratios: men 0.74 (0.51 to 1.09); women 0.43 (0.20 to 0.95)). CONCLUSIONS Frequency and quantity of alcohol consumption are important in assessing the risk of a major coronary event. Risk is lowest among men who report one to four drinks daily on five or six days a week and among women who report one or two drinks daily on five or six days a week.

negative: Pleiotropic effects of statins. Statins are potent inhibitors of cholesterol biosynthesis. In clinical trials, statins are beneficial in the primary and secondary prevention of coronary heart disease. However, the overall benefits observed with statins appear to be greater than what might be expected from changes in lipid levels alone, suggesting effects beyond cholesterol lowering. Indeed, recent studies indicate that some of the cholesterol-independent or "pleiotropic" effects of statins involve improving endothelial function, enhancing the stability of atherosclerotic plaques, decreasing oxidative stress and inflammation, and inhibiting the thrombogenic response. Furthermore, statins have beneficial extrahepatic effects on the immune system, CNS, and bone. Many of these pleiotropic effects are mediated by inhibition of isoprenoids, which serve as lipid attachments for intracellular signaling molecules. In particular, inhibition of small GTP-binding proteins, Rho, Ras, and Rac, whose proper membrane localization and function are dependent on isoprenylation, may play an important role in mediating the pleiotropic effects of statins.

negative: Coronary plaque disruption. Coronary atherosclerosis is by far the most frequent cause of ischemic heart disease, and plaque disruption with superimposed thrombosis is the main cause of the acute coronary syndromes of unstable angina, myocardial infarction, and sudden death.1 2 3 4 5 Therefore, for event-free survival, the vital question is not why atherosclerosis develops but rather why, after years of indolent growth, it suddenly becomes complicated by life-threatening thrombosis. The composition and vulnerability of plaque rather than its volume or the consequent severity of stenosis produced have emerged as being the most important determinants for the development of the thrombus-mediated acute coronary syndromes; lipid-rich and soft plaques are more dangerous than collagen-rich and hard plaques because they are more unstable and rupture-prone and highly thrombogenic after disruption.6 This review will explore potential mechanisms responsible for the sudden conversion of a stable atherosclerotic plaque to an unstable and life-threatening atherothrombotic lesion—an event known as plaque fissuring, rupture, or disruption.7 8   Atherosclerosis is the result of a complex interaction between blood elements, disturbed flow, and vessel wall abnormality, involving several pathological processes: inflammation, with increased endothelial permeability, endothelial activation, and monocyte recruitment9 10 11 12 13 14 ; growth, with smooth muscle cell (SMC) proliferation, migration, and matrix synthesis15 16 ; degeneration, with lipid accumulation17 18 ; necrosis, possibly related to the cytotoxic effect of oxidized lipid19 ; calcification/ossification, which may represent an active rather than a dystrophic process20 21 ; and thrombosis, with platelet recruitment and fibrin formation.1 22 23 Thrombotic factors may play a role early during atherogenesis, but a flow-limiting thrombus does not develop until mature plaques are present, which is why thrombosis often is classified as a complication rather than a genuine component of atherosclerosis. ### Mature Plaques: Atherosis and Sclerosis   As the name atherosclerosis implies, mature …

negative: A subset of 26S proteasomes is activated at critically low ATP concentrations and contributes to myocardial injury during cold ischemia. Molecular mechanisms leading to myocardial injury during warm or cold ischemia are insufficiently understood. Although proteasomes are thought to contribute to myocardial ischemia-reperfusion injury, their roles during the ischemic period remain elusive. Because donor hearts are commonly exposed to prolonged global cold ischemia prior to cardiac transplantation, we evaluated the role and regulation of the proteasome during cold ischemic storage of rat hearts in context of the myocardial ATP content. When measured at the actual tissue ATP concentration, cardiac proteasome peptidase activity increased by 225% as ATP declined during cold ischemic storage of hearts in University of Wisconsin (UW) solution for up to 48h. Addition of the specific proteasome inhibitor epoxomicin to the UW solution inhibited proteasome activity in the cardiac extracts, significantly reduced edema formation and preserved the ultrastructural integrity of the cardiomyocyte. Utilizing purified 20S/26S proteasome enzyme preparations, we demonstrate that this activation can be attributed to a subset of 26S proteasomes which are stable at ATP concentrations far below physiological levels, that ATP negatively regulates its activity and that maximal activation occurs at ATP concentrations in the low mumol/L range. These data suggest that proteasome activation is a pathophysiologically relevant mechanism of cold ischemic myocardial injury. A subset of 26S proteasomes appears to be a cell-destructive protease that is activated as ATP levels decline. Proteasome inhibition during cold ischemia preserves the ultrastructural integrity of the cardiomyocyte.

negative: Myeloid differentiation factor-88/interleukin-1 signaling controls cardiac fibrosis and heart failure progression in inflammatory dilated cardiomyopathy. RATIONALE The myeloid differentiation factor (MyD)88/interleukin (IL)-1 axis activates self-antigen-presenting cells and promotes autoreactive CD4(+) T-cell expansion in experimental autoimmune myocarditis, a mouse model of inflammatory heart disease. OBJECTIVE The aim of this study was to determine the role of MyD88 and IL-1 in the progression of acute myocarditis to an end-stage heart failure. METHODS AND RESULTS Using alpha-myosin heavy chain peptide (MyHC-alpha)-loaded, activated dendritic cells, we induced myocarditis in wild-type and MyD88(-/-) mice with similar distributions of heart-infiltrating cell subsets and comparable CD4(+) T-cell responses. Injection of complete Freund's adjuvant (CFA) or MyHC-alpha/CFA into diseased mice promoted cardiac fibrosis, induced ventricular dilation, and impaired heart function in wild-type but not in MyD88(-/-) mice. Experiments with chimeric mice confirmed the bone marrow origin of the fibroblasts replacing inflammatory infiltrates and showed that MyD88 and IL-1 receptor type I signaling on bone marrow-derived cells was critical for development of cardiac fibrosis during progression to heart failure. CONCLUSIONS Our findings indicate a critical role of MyD88/IL-1 signaling in the bone marrow compartment in postinflammatory cardiac fibrosis and heart failure and point to novel therapeutic strategies against inflammatory cardiomyopathy.

negative: Fibroblast Growth Factor 21 Prevents Atherosclerosis by Suppression of Hepatic Sterol Regulatory Element-Binding Protein-2 and Induction of Adiponectin in Mice BACKGROUND Fibroblast growth factor 21 (FGF21) is a metabolic hormone with pleiotropic effects on glucose and lipid metabolism and insulin sensitivity. It acts as a key downstream target of both peroxisome proliferator-activated receptor α and γ, the agonists of which have been used for lipid lowering and insulin sensitization, respectively. However, the role of FGF21 in the cardiovascular system remains elusive. METHODS AND RESULTS The roles of FGF21 in atherosclerosis were investigated by evaluating the impact of FGF21 deficiency and replenishment with recombinant FGF21 in apolipoprotein E(-/-) mice. FGF21 deficiency causes a marked exacerbation of atherosclerotic plaque formation and premature death in apolipoprotein E(-/-) mice, which is accompanied by hypoadiponectinemia and severe hypercholesterolemia. Replenishment of FGF21 protects against atherosclerosis in apolipoprotein E(-/-)mice via 2 independent mechanisms, inducing the adipocyte production of adiponectin, which in turn acts on the blood vessels to inhibit neointima formation and macrophage inflammation, and suppressing the hepatic expression of the transcription factor sterol regulatory element-binding protein-2, thereby leading to reduced cholesterol synthesis and attenuation of hypercholesterolemia. Chronic treatment with adiponectin partially reverses atherosclerosis without obvious effects on hypercholesterolemia in FGF21-deficient apolipoprotein E(-/-) mice. By contrast, the cholesterol-lowering effects of FGF21 are abrogated by hepatic expression of sterol regulatory element-binding protein-2. CONCLUSIONS FGF21 protects against atherosclerosis via fine tuning the multiorgan crosstalk among liver, adipose tissue, and blood vessels.

negative: Network meta-analysis for indirect treatment comparisons. I present methods for assessing the relative effectiveness of two treatments when they have not been compared directly in a randomized trial but have each been compared to other treatments. These network meta-analysis techniques allow estimation of both heterogeneity in the effect of any given treatment and inconsistency ('incoherence') in the evidence from different pairs of treatments. A simple estimation procedure using linear mixed models is given and used in a meta-analysis of treatments for acute myocardial infarction.

negative: KLF4-dependent phenotypic modulation of smooth muscle cells has a key role in atherosclerotic plaque pathogenesis Previous studies investigating the role of smooth muscle cells (SMCs) and macrophages in the pathogenesis of atherosclerosis have provided controversial results owing to the use of unreliable methods for clearly identifying each of these cell types. Here, using Myh11-CreERT2 ROSA floxed STOP eYFP Apoe−/− mice to perform SMC lineage tracing, we find that traditional methods for detecting SMCs based on immunostaining for SMC markers fail to detect >80% of SMC-derived cells within advanced atherosclerotic lesions. These unidentified SMC-derived cells exhibit phenotypes of other cell lineages, including macrophages and mesenchymal stem cells (MSCs). SMC-specific conditional knockout of Krüppel-like factor 4 (Klf4) resulted in reduced numbers of SMC-derived MSC- and macrophage-like cells, a marked reduction in lesion size, and increases in multiple indices of plaque stability, including an increase in fibrous cap thickness as compared to wild-type controls. On the basis of in vivo KLF4 chromatin immunoprecipitation–sequencing (ChIP-seq) analyses and studies of cholesterol-treated cultured SMCs, we identified >800 KLF4 target genes, including many that regulate pro-inflammatory responses of SMCs. Our findings indicate that the contribution of SMCs to atherosclerotic plaques has been greatly underestimated, and that KLF4-dependent transitions in SMC phenotype are critical in lesion pathogenesis.

negative: the Development of Autoimmune Myocarditis in Mice by an BACKGROUND Interleukin (IL)-12 exerts a potent proinflammatory effect by stimulating T-helper (Th) 1 responses. This effect is believed to be mediated primarily through the activation of STAT4 and subsequent production of interferon (IFN)-gamma. Methods and Results- We examined the role of IL-12 receptor (IL-12R) signaling in the development of murine experimental autoimmune myocarditis (EAM) induced by cardiac myosin immunization. Both IL-12Rbeta1-deficient mice and STAT4-deficient mice were resistant to the induction of myocarditis. Treatment with exogenous IL-12 exacerbated disease. We questioned whether IFN-gamma is required for the disease-promoting activity of IL-12. On the contrary, we found that IFN-gamma suppresses EAM. Lack of IFN-gamma due to either depletion with an antibody or a genetic deficiency exacerbated myocarditis. Spleens from IFN-gamma-deficient mice immunized with cardiac myosin showed increased cellularity; greater numbers of CD3+, CD4+, CD8+, and IL-2-producing cells; and heightened ability to produce cytokines on stimulation in vitro. Treatment of mice with recombinant IFN-gamma suppressed the development of myocarditis. CONCLUSIONS IL-12/IL-12R/STAT4 signaling promotes the development of EAM. In contrast, IFN-gamma plays a protective role. The disease-limiting effects of IFN-gamma might be explained by its ability to control the expansion of activated T lymphocytes.

negative: Inflammatory monocyte/macrophage modulation by liposome-entrapped spironolactone ameliorates acute lung injury in mice. AIM To examine the therapeutic/preventive potential of liposome-encapsulated spironolactone (SP; Lipo-SP) for acute lung injury (ALI) and fibrosis. MATERIALS & METHODS Lipo-SP was prepared by the film-ultrasonic method, and physicochemical and pharmacokinetic characterized for oral administration (10 and 20 mg/kg for SP-loaded liposome; 20 mg/kg for free SP) in a mouse model bleomycin-induced ALI. RESULTS Lipo-SP enhanced bioavailability of SP with significant amelioration in lung pathology. Mechanistically, SP-mediated mineralocorticoid receptor antagonism contributes to inflammatory monocyte/macrophage modulation via an inhibitory effect on Ly6C(hi) monocytosis-directed M2 polarization of alveolar macrophages. Moreover, Lipo-SP at lower dose (10 mg/kg) exhibited more improvement in body weight gain. CONCLUSION Our data highlight Lipo-SP as a promising approach with therapeutic/preventive potential for ALI and fibrosis.

negative: Prevention of coronary heart disease with pravastatin in men with hypercholesterolemia. West of Scotland Coronary Prevention Study Group. BACKGROUND Lowering the blood cholesterol level may reduce the risk of coronary heart disease. This double-blind study was designed to determine whether the administration of pravastatin to men with hypercholesterolemia and no history of myocardial infarction reduced the combined incidence of nonfatal myocardial infarction and death from coronary heart disease. METHODS We randomly assigned 6595 men, 45 to 64 years of age, with a mean (+/- SD) plasma cholesterol level of 272 +/- 23 mg per deciliter (7.0 +/- 0.6 mmol per liter) to receive pravastatin (40 mg each evening) or placebo. The average follow-up period was 4.9 years. Medical records, electrocardiographic recordings, and the national death registry were used to determine the clinical end points. RESULTS Pravastatin lowered plasma cholesterol levels by 20 percent and low-density-lipoprotein cholesterol levels by 26 percent, whereas there was no change with placebo. There were 248 definite coronary events (specified as nonfatal myocardial infarction or death from coronary heart disease) in the placebo group, and 174 in the pravastatin group (relative reduction in risk with pravastatin, 31 percent; 95 percent confidence interval, 17 to 43 percent; P < 0.001). There were similar reductions in the risk of definite nonfatal myocardial infarctions (31 percent reduction, P < 0.001), death from coronary heart disease (definite cases alone: 28 percent reduction, P = 0.13; definite plus suspected cases: 33 percent reduction, P = 0.042), and death from all cardiovascular causes (32 percent reduction, P = 0.033). There was no excess of deaths from noncardiovascular causes in the pravastatin group. We observed a 22 percent reduction in the risk of death from any cause in the pravastatin group (95 percent confidence interval, 0 to 40 percent; P = 0.051). CONCLUSIONS Treatment with pravastatin significantly reduced the incidence of myocardial infarction and death from cardiovascular causes without adversely affecting the risk of death from noncardiovascular causes in men with moderate hypercholesterolemia and no history of myocardial infarction.

negative: Activation of liver X receptors and retinoid X receptors prevents bacterial-induced macrophage apoptosis. Microbe-macrophage interactions play a central role in the pathogenesis of many infections. The ability of some bacterial pathogens to induce macrophage apoptosis has been suggested to contribute to their ability to elude innate immune responses and successfully colonize the host. Here, we provide evidence that activation of liver X receptors (LXRs) and retinoid X receptors (RXRs) inhibits apoptotic responses of macrophages to macrophage colony-stimulating factor (M-CSF) withdrawal and several inducers of apoptosis. In addition, combined activation of LXR and RXR protected macrophages from apoptosis caused by infection with Bacillus anthracis, Escherichia coli, and Salmonella typhimurium. Expression-profiling studies demonstrated that LXR and RXR agonists induced the expression of antiapoptotic regulators, including AIM/CT2, Bcl-X(L), and Birc1a. Conversely, LXR and RXR agonists inhibited expression of proapoptotic regulators and effectors, including caspases 1, 4/11, 7, and 12; Fas ligand; and Dnase1l3. The combination of LXR and RXR agonists was more effective than either agonist alone at inhibiting apoptosis in response to various inducers of apoptosis, and it acted synergistically to induce expression of AIM/CT2. Inhibition of AIM/CT2 expression in response to LXR/RXR agonists partially reversed their antiapoptotic effects. These findings reveal unexpected roles of LXRs and RXRs in the control of macrophage survival and raise the possibility that LXR/RXR agonists may be exploited to enhance innate immunity to bacterial pathogens that induce apoptotic programs as a strategy for evading host responses.

negative: Scaffold-based three-dimensional human fibroblast culture provides a structural matrix that supports angiogenesis in infarcted heart tissue. BACKGROUND We have developed techniques to implant angiogenic patches onto the epicardium over regions of infarcted cardiac tissue to stimulate revascularization of the damaged tissue. These experiments used a scaffold-based 3D human dermal fibroblast culture (3DFC) as an epicardial patch. The 3DFC contains viable cells that secrete angiogenic growth factors and has previously been shown to stimulate angiogenic activity. The hypothesis tested was that a viable 3DFC cardiac patch would stimulate an angiogenic response within an area of infarcted cardiac tissue. METHODS AND RESULTS A coronary occlusion of a branch of the left anterior descending coronary artery was performed by thermal ligation in severe combined immunodeficient mice. 3DFCs with or without viable cells were sized to the damaged area, implanted in replicate mice onto the epicardium at the site of tissue injury, and compared with animals that received infarct surgery but no implant. Fourteen and 30 days after surgery, hearts were exposed and photographed, and tissue samples were prepared for histology and cytochemistry. Fourteen and 30 days after surgery, the damaged myocardium receiving viable 3DFC exhibited a significantly greater angiogenic response (including arterioles, venules, and capillaries) than nonviable and untreated control groups. CONCLUSIONS In this animal model, viable 3DFC stimulates angiogenesis within a region of cardiac infarction and can augment a repair response in damaged tissue. Therefore, a potential use for 3DFC is the repair of myocardial tissue damaged by infarction.

negative: A classification of unstable angina revisited. Unstable angina is a critical phase of coronary heart disease with widely variable symptoms and prognosis. A decade ago, a classification of unstable angina based on clinical symptoms was introduced. This system was then validated by prospective clinical studies to correlate with the prognosis and was linked to angiographic and histological findings. It has been used to categorize patients in many large clinical trials. In recent years, the pathophysiological roles of platelet activation and inflammation in unstable angina have been elucidated. Subsequently, improved markers of myocardial injury, acute-phase proteins, and hemostatic markers that may be associated with clinical outcomes have been identified. Particularly, cardiac-specific troponin T and troponin I have been shown to represent the best predictors of early risk in patients with angina at rest. Accordingly, it is suggested that the original classification be extended by subclassifying one large group of unstable angina patients, ie, those with angina at rest within the past 48 hours (class IIIB), into troponin-positive (T(pos)) and troponin-negative (T(neg)) patients. The 30-days risk for death and myocardial infarction is considered to be up to 20% in class IIIB-T(pos) but <2% in class IIIB-T(neg) patients. Initial results suggest that troponins may function as surrogate markers for thrombus formation and can effectively guide therapy with glycoprotein IIb/IIIa antagonists or low-molecular-weight heparins. These observations provide additional impetus for adding the measurement of these markers to the clinical classification and represent a novel concept of treating these high-risk patients.

negative: Lethal autoimmune myocarditis in interferon-gamma receptor-deficient mice: enhanced disease severity by impaired inducible nitric oxide synthase induction. BACKGROUND Interferon-gamma (IFN-gamma) is an essential cytokine in the regulation of inflammatory responses in autoimmune diseases. Little is known about its role in inflammatory heart disease. METHODS AND RESULTS We showed that IFN-gamma receptor-deficient mice (IFN-gammaR(-/-)) on a BALB/c background immunized with a peptide derived from cardiac alpha-myosin heavy chain develop severe myocarditis with high mortality. Although myocarditis subsided in wild-type mice after 3 weeks, IFN-gammaR(-/-) mice showed persistent disease. The persistent inflammation was accompanied by vigorous in vitro CD4 T-cell responses and impaired inducible nitric oxide synthase expression, together with evidence of impaired nitric oxide production in IFN-gammaR(-/-) hearts. Treatment of wild-type mice with the nitric oxide synthetase inhibitor N:-nitro-l-arginine-methyl-ester enhanced in vitro CD4 T-cell proliferation and prevented healing of myocarditis. CONCLUSIONS Our data provide evidence that IFN-gamma protects mice from lethal autoimmune myocarditis by inducing the expression of inducible nitric oxide synthase followed by the downregulation of T-cell responses.

negative: The Long Noncoding RNA CAREL Controls Cardiac Regeneration. BACKGROUND Adult mammalian heart loses regeneration ability following ischemic injury due to the loss of cardiomyocyte mitosis. However, the molecular mechanisms underlying the post-mitotic nature of cardiomyocytes remain largely unknown. OBJECTIVES The purpose of this study was to define the essential role of long noncoding ribonucleic acids (lncRNAs) in heart regeneration during postnatal and adult injury. METHODS Myh6-driving cardiomyocyte-specific lncRNA-CAREL transgenic mice and adenovirus-mediated in vivo silencing of endogenous CAREL were used in this study. The effect of CAREL on cardiomyocyte replication and heart regeneration after apical resection or myocardial infarction was assessed by detecting mitosis and cytokinesis. RESULTS An lncRNA CAREL was found significantly up-regulated in cardiomyocytes from neonatal mice (P7) in parallel with loss of regenerative capacity. Cardiac-specific overexpression of CAREL in mice reduced cardiomyocyte division and proliferation and blunted neonatal heart regeneration after injury. Conversely, silencing of CAREL in vivo markedly promoted cardiac regeneration and improved heart functions after myocardial infarction in neonatal and adult mice. CAREL acted as a competing endogenous ribonucleic acid for miR-296 to derepress the expression of Trp53inp1 and Itm2a, the target genes of miR-296. Consistently, overexpression of miR-296 significantly increased cardiomyocyte replication and cardiac regeneration after injury. Decline of cardiac regenerative ability in CAREL transgenic mice was also rescued by miR-296. A short fragment containing the conserved sequence of CAREL reduced the proliferation of human induced pluripotent stem cell-derived cardiomyocytes as the full-length CAREL. CONCLUSIONS LncRNA CAREL regulates cardiomyocyte proliferation and heart regeneration in postnatal and adult heart after injury by acting as a competing endogenous ribonucleic acid on miR-296 that targets Trp53inp1 and Itm2a.

negative: Embryonic Stem Cells for Severe Heart Failure: Why and How? The experience accumulated in cardiac cell therapy suggests that regeneration of extensively necrotic myocardial areas is unlikely to be achieved by the sole paracrine effects of the grafted cells but rather requires the conversion of these cells into cardiomyocytes featuring the capacity to substitute for those which have been irreversibly lost. In this setting, the use of human pluripotent embryonic stem cells has a strong rationale. The experimental results obtained in animal models of myocardial infarction are encouraging. However, the switch to clinical applications still requires to address some critical issues, among which the optimization of the cardiac specification of the embryonic stem cells, the purification of the resulting progenitor cells so as to graft a purified population devoid from any contamination by residual pluripotent cells which carry the risk of tumorigenesis, and the control of the expected allogeneic rejection by clinically acceptable methods. If the solution to these problems is a prerequisite, the therapeutic success of this approach will also depend on the capacity to efficiently transfer the cells to the target tissue, to keep them alive once engrafted, and to allow them to spatially organize in such a way that they can contribute to the contractile function of the heart.

negative: CD11b+ monocytes abrogate Th17 CD4+ T cell-mediated experimental autoimmune myocarditis. Experimental autoimmune myocarditis (EAM) represents a Th17 T cell-mediated mouse model of postinflammatory heart disease. In BALB/c wild-type mice, EAM is a self-limiting disease, peaking 21 days after alpha-myosin H chain peptide (MyHC-alpha)/CFA immunization and largely resolving thereafter. In IFN-gammaR(-/-) mice, however, EAM is exacerbated and shows a chronic progressive disease course. We found that this progressive disease course paralleled persistently elevated IL-17 release from T cells infiltrating the hearts of IFN-gammaR(-/-) mice 30 days after immunization. In fact, IL-17 promoted the recruitment of CD11b(+) monocytes, the major heart-infiltrating cells in EAM. In turn, CD11b(+) monocytes suppressed MyHC-alpha-specific Th17 T cell responses IFN-gamma-dependently in vitro. In vivo, injection of IFN-gammaR(+/+)CD11b(+), but not IFN-gammaR(-/-)CD11b(+), monocytes, suppressed MyHC-alpha-specific T cells, and abrogated the progressive disease course in IFN-gammaR(-/-) mice. Finally, coinjection of MyHC-alpha-specific, but not OVA-transgenic, IFN-gamma-releasing CD4(+) Th1 T cell lines, together with MyHC-alpha-specific Th17 T cells protected RAG2(-/-) mice from EAM. In conclusion, CD11b(+) monocytes play a dual role in EAM: as a major cellular substrate of IL-17-induced inflammation and as mediators of an IFN-gamma-dependent negative feedback loop confining disease progression.


query: Transplanted human glial cells can differentiate within the host animal.

positive: Forebrain engraftment by human glial progenitor cells enhances synaptic plasticity and learning in adult mice. Human astrocytes are larger and more complex than those of infraprimate mammals, suggesting that their role in neural processing has expanded with evolution. To assess the cell-autonomous and species-selective properties of human glia, we engrafted human glial progenitor cells (GPCs) into neonatal immunodeficient mice. Upon maturation, the recipient brains exhibited large numbers and high proportions of both human glial progenitors and astrocytes. The engrafted human glia were gap-junction-coupled to host astroglia, yet retained the size and pleomorphism of hominid astroglia, and propagated Ca2+ signals 3-fold faster than their hosts. Long-term potentiation (LTP) was sharply enhanced in the human glial chimeric mice, as was their learning, as assessed by Barnes maze navigation, object-location memory, and both contextual and tone fear conditioning. Mice allografted with murine GPCs showed no enhancement of either LTP or learning. These findings indicate that human glia differentially enhance both activity-dependent plasticity and learning in mice.

negative: Direct isolation of human central nervous system stem cells. Stem cells, which are clonogenic cells with self-renewal and multilineage differentiation properties, have the potential to replace or repair damaged tissue. We have directly isolated clonogenic human central nervous system stem cells (hCNS-SC) from fresh human fetal brain tissue, using antibodies to cell surface markers and fluorescence-activated cell sorting. These hCNS-SC are phenotypically 5F3 (CD133)(+), 5E12(+), CD34(-), CD45(-), and CD24(-/lo). Single CD133(+) CD34(-) CD45(-) sorted cells initiated neurosphere cultures, and the progeny of clonogenic cells could differentiate into both neurons and glial cells. Single cells from neurosphere cultures initiated from CD133(+) CD34(-) CD45(-) cells were again replated as single cells and were able to reestablish neurosphere cultures, demonstrating the self-renewal potential of this highly enriched population. Upon transplantation into brains of immunodeficient neonatal mice, the sorted/expanded hCNS-SC showed potent engraftment, proliferation, migration, and neural differentiation.

negative: Somatic sex identity is cell-autonomous in the chicken In the mammalian model of sex determination, embryos are considered to be sexually indifferent until the transient action of a sex-determining gene initiates gonadal differentiation. Although this model is thought to apply to all vertebrates, this has yet to be established. Here we have examined three lateral gynandromorph chickens (a rare, naturally occurring phenomenon in which one side of the animal appears male and the other female) to investigate the sex-determining mechanism in birds. These studies demonstrated that gynandromorph birds are genuine male:female chimaeras, and indicated that male and female avian somatic cells may have an inherent sex identity. To test this hypothesis, we transplanted presumptive mesoderm between embryos of reciprocal sexes to generate embryos containing male:female chimaeric gonads. In contrast to the outcome for mammalian mixed-sex chimaeras, in chicken mixed-sex chimaeras the donor cells were excluded from the functional structures of the host gonad. In an example where female tissue was transplanted into a male host, donor cells contributing to the developing testis retained a female identity and expressed a marker of female function. Our study demonstrates that avian somatic cells possess an inherent sex identity and that, in birds, sexual differentiation is substantively cell autonomous.

negative: Development of a novel mouse glioma model using lentiviral vectors We report the development of a new method to induce glioblastoma multiforme in adult immunocompetent mice by injecting Cre-loxP–controlled lentiviral vectors expressing oncogenes. Cell type- or region-specific expression of activated forms of the oncoproteins Harvey-Ras and AKT in fewer than 60 glial fibrillary acidic protein–positive cells in the hippocampus, subventricular zone or cortex of mice heterozygous for the gene encoding the tumor suppressor Tp53 were tested. Mice developed glioblastoma multiforme when transduced either in the subventricular zone or the hippocampus. However, tumors were rarely detected when the mice were transduced in the cortex. Transplantation of brain tumor cells into naive recipient mouse brain resulted in the formation of glioblastoma multiforme–like tumors, which contained CD133+ cells, formed tumorspheres and could differentiate into neurons and astrocytes. We suggest that the use of Cre-loxP–controlled lentiviral vectors is a novel way to generate a mouse glioblastoma multiforme model in a region- and cell type-specific manner in adult mice.

negative: Recipient-type specific CD4+CD25+ regulatory T cells favor immune reconstitution and control graft-versus-host disease while maintaining graft-versus-leukemia. CD4+CD25+ regulatory T cells (Treg's) play a pivotal role in preventing organ-specific autoimmune diseases and in inducing tolerance to allogeneic organ transplants. We and others recently demonstrated that high numbers of Treg's can also modulate graft-versus-host disease (GVHD) if administered in conjunction with allogeneic hematopoietic stem cell transplantation in mice. In a clinical setting, it would be impossible to obtain enough freshly purified Treg's from a single donor to have a therapeutic effect. Thus, we performed regulatory T cell expansion ex vivo by stimulation with allogeneic APCs, which has the additional effect of producing alloantigen-specific regulatory T cells. Here we show that regulatory T cells specific for recipient-type alloantigens control GVHD while favoring immune reconstitution. Irrelevant regulatory T cells only mediate a partial protection from GVHD. Preferential survival of specific regulatory T cells, but not of irrelevant regulatory T cells, was observed in grafted animals. Additionally, the use of specific regulatory T cells was compatible with some form of graft-versus-tumor activity. These data suggest that recipient-type specific Treg's could be preferentially used in the control of GVHD in future clinical trials.

negative: Identification of genes associated with the astrocyte-specific gene Gfap during astrocyte differentiation. Chromosomes and genes are non-randomly arranged within the mammalian cell nucleus, and gene clustering is of great significance in transcriptional regulation. However, the relevance of gene clustering and their expression during the differentiation of neural precursor cells (NPCs) into astrocytes remains unclear. We performed a genome-wide enhanced circular chromosomal conformation capture (e4C) to screen for genes associated with the astrocyte-specific gene glial fibrillary acidic protein (Gfap) during astrocyte differentiation. We identified 18 genes that were specifically associated with Gfap and expressed in NPC-derived astrocytes. Our results provide additional evidence for the functional significance of gene clustering in transcriptional regulation during NPC differentiation.

negative: Cerebral organoids model human brain development and microcephaly The complexity of the human brain has made it difficult to study many brain disorders in model organisms, highlighting the need for an in vitro model of human brain development. Here we have developed a human pluripotent stem cell-derived three-dimensional organoid culture system, termed cerebral organoids, that develop various discrete, although interdependent, brain regions. These include a cerebral cortex containing progenitor populations that organize and produce mature cortical neuron subtypes. Furthermore, cerebral organoids are shown to recapitulate features of human cortical development, namely characteristic progenitor zone organization with abundant outer radial glial stem cells. Finally, we use RNA interference and patient-specific induced pluripotent stem cells to model microcephaly, a disorder that has been difficult to recapitulate in mice. We demonstrate premature neuronal differentiation in patient organoids, a defect that could help to explain the disease phenotype. Together, these data show that three-dimensional organoids can recapitulate development and disease even in this most complex human tissue.

negative: Advances in graft-versus-host disease biology and therapy Allogeneic haematopoietic stem cell transplantation is used to treat a variety of disorders, but its efficacy is limited by the occurrence of graft-versus-host disease (GVHD). The past decade has brought impressive advances in our understanding of the role of stimulatory and suppressive elements of the adaptive and innate immune systems from both the donor and the host in GVHD pathogenesis. New insights from basic immunology, preclinical models and clinical studies have led to novel approaches for prevention and treatment. This Review highlights the recent advances in understanding the pathophysiology of GVHD and its treatment, with a focus on manipulations of the immune system that are amenable to clinical application.

negative: Reversal of hyperglycemia in mice by using human expandable insulin-producing cells differentiated from fetal liver progenitor cells. Beta-cell replacement is considered to be the most promising approach for treatment of type 1 diabetes. Its application on a large scale is hindered by a shortage of cells for transplantation. Activation of insulin expression, storage, and regulated secretion in stem/progenitor cells offers novel ways to overcome this shortage. We explored whether fetal human progenitor liver cells (FH) could be induced to differentiate into insulin-producing cells after expression of the pancreatic duodenal homeobox 1 (Pdx1) gene, which is a key regulator of pancreatic development and insulin expression in beta cells. FH cells possess a considerable replication capacity, and this was further extended by introduction of the gene for the catalytic subunit of human telomerase. Immortalized FH cells expressing Pdx1 activated multiple beta-cell genes, produced and stored considerable amounts of insulin, and released insulin in a regulated manner in response to glucose. When transplanted into hyperglycemic immunodeficient mice, the cells restored and maintained euglycemia for prolonged periods. Quantitation of human C-peptide in the mouse serum confirmed that the glycemia was normalized by the transplanted human cells. This approach offers the potential of a novel source of cells for transplantation into patients with type 1 diabetes.

negative: Human and murine very small embryonic-like cells represent multipotent tissue progenitors, in vitro and in vivo. The purpose of this study was to determine the lineage progression of human and murine very small embryonic-like (HuVSEL or MuVSEL) cells in vitro and in vivo. In vitro, HuVSEL and MuVSEL cells differentiated into cells of all three embryonic germ layers. HuVSEL cells produced robust mineralized tissue of human origin compared with controls in calvarial defects. Immunohistochemistry demonstrated that the HuVSEL cells gave rise to neurons, adipocytes, chondrocytes, and osteoblasts within the calvarial defects. MuVSEL cells were also able to differentiate into similar lineages. First round serial transplants of MuVSEL cells into irradiated osseous sites demonstrated that ∼60% of the cells maintained their VSEL cell phenotype while other cells differentiated into multiple tissues at 3 months. Secondary transplants did not identify donor VSEL cells, suggesting limited self renewal but did demonstrate VSEL cell derivatives in situ for up to 1 year. At no point were teratomas identified. These studies show that VSEL cells produce multiple cellular structures in vivo and in vitro and lay the foundation for future cell-based regenerative therapies for osseous, neural, and connective tissue disorders.

negative: Pericytes of human skeletal muscle are myogenic precursors distinct from satellite cells Cells derived from blood vessels of human skeletal muscle can regenerate skeletal muscle, similarly to embryonic mesoangioblasts. However, adult cells do not express endothelial markers, but instead express markers of pericytes, such as NG2 proteoglycan and alkaline phosphatase (ALP), and can be prospectively isolated from freshly dissociated ALP+ cells. Unlike canonical myogenic precursors (satellite cells), pericyte-derived cells express myogenic markers only in differentiated myotubes, which they form spontaneously with high efficiency. When transplanted into severe combined immune deficient–X-linked, mouse muscular dystrophy (scid–mdx) mice, pericyte-derived cells colonize host muscle and generate numerous fibres expressing human dystrophin. Similar cells isolated from Duchenne patients, and engineered to express human mini-dystrophin, also give rise to many dystrophin-positive fibres in vivo. These data show that myogenic precursors, distinct from satellite cells, are associated with microvascular walls in the human skeletal muscle, may represent a correlate of embryonic 'mesoangioblasts' present after birth and may be a promising candidate for future cell-therapy protocols in patients.

negative: Establishment of human iPSC-based models for the study and targeting of glioma initiating cells Glioma tumour-initiating cells (GTICs) can originate upon the transformation of neural progenitor cells (NPCs). Studies on GTICs have focused on primary tumours from which GTICs could be isolated and the use of human embryonic material. Recently, the somatic genomic landscape of human gliomas has been reported. RTK (receptor tyrosine kinase) and p53 signalling were found dysregulated in ∼90% and 86% of all primary tumours analysed, respectively. Here we report on the use of human-induced pluripotent stem cells (hiPSCs) for modelling gliomagenesis. Dysregulation of RTK and p53 signalling in hiPSC-derived NPCs (iNPCs) recapitulates GTIC properties in vitro. In vivo transplantation of transformed iNPCs leads to highly aggressive tumours containing undifferentiated stem cells and their differentiated derivatives. Metabolic modulation compromises GTIC viability. Last, screening of 101 anti-cancer compounds identifies three molecules specifically targeting transformed iNPCs and primary GTICs. Together, our results highlight the potential of hiPSCs for studying human tumourigenesis.

negative: Direct reprogramming of mouse fibroblasts to neural progenitors. The simple yet powerful technique of induced pluripotency may eventually supply a wide range of differentiated cells for cell therapy and drug development. However, making the appropriate cells via induced pluripotent stem cells (iPSCs) requires reprogramming of somatic cells and subsequent redifferentiation. Given how arduous and lengthy this process can be, we sought to determine whether it might be possible to convert somatic cells into lineage-specific stem/progenitor cells of another germ layer in one step, bypassing the intermediate pluripotent stage. Here we show that transient induction of the four reprogramming factors (Oct4, Sox2, Klf4, and c-Myc) can efficiently transdifferentiate fibroblasts into functional neural stem/progenitor cells (NPCs) with appropriate signaling inputs. Compared with induced neurons (or iN cells, which are directly converted from fibroblasts), transdifferentiated NPCs have the distinct advantage of being expandable in vitro and retaining the ability to give rise to multiple neuronal subtypes and glial cells. Our results provide a unique paradigm for iPSC-factor-based reprogramming by demonstrating that it can be readily modified to serve as a general platform for transdifferentiation.

negative: Transdifferentiation of glioblastoma cells into vascular endothelial cells. Glioblastoma (GBM) is the most malignant brain tumor and is highly resistant to intensive combination therapies and anti-VEGF therapies. To assess the resistance mechanism to anti-VEGF therapy, we examined the vessels of GBMs in tumors that were induced by the transduction of p53(+/-) heterozygous mice with lentiviral vectors containing oncogenes and the marker GFP in the hippocampus of GFAP-Cre recombinase (Cre) mice. We were surprised to observe GFP(+) vascular endothelial cells (ECs). Transplantation of mouse GBM cells revealed that the tumor-derived endothelial cells (TDECs) originated from tumor-initiating cells and did not result from cell fusion of ECs and tumor cells. An in vitro differentiation assay suggested that hypoxia is an important factor in the differentiation of tumor cells to ECs and is independent of VEGF. TDEC formation was not only resistant to an anti-VEGF receptor inhibitor in mouse GBMs but it led to an increase in their frequency. A xenograft model of human GBM spheres from clinical specimens and direct clinical samples from patients with GBM also showed the presence of TDECs. We suggest that the TDEC is an important player in the resistance to anti-VEGF therapy, and hence a potential target for GBM therapy.

negative: Viral Infection of Engrafted Human Islets Leads to Diabetes Type 1 diabetes (T1D) is characterized by the destruction of the insulin-producing β-cells of pancreatic islets. Genetic and environmental factors both contribute to T1D development. Viral infection with enteroviruses is a suspected trigger for T1D, but a causal role remains unproven and controversial. Studies in animals are problematic because of species-specific differences in host cell susceptibility and immune responses to candidate viral pathogens such as coxsackievirus B (CVB). In order to resolve the controversial role of viruses in human T1D, we developed a viral infection model in immunodeficient mice bearing human islet grafts. Hyperglycemia was induced in mice by specific ablation of native β-cells. Human islets, which are naturally susceptible to CVB infection, were transplanted to restore normoglycemia. Transplanted mice were infected with CVB4 and monitored for hyperglycemia. Forty-seven percent of CVB4-infected mice developed hyperglycemia. Human islet grafts from infected mice contained viral RNA, expressed viral protein, and had reduced insulin levels compared with grafts from uninfected mice. Human-specific gene expression profiles in grafts from infected mice revealed the induction of multiple interferon-stimulated genes. Thus, human islets can become severely dysfunctional with diminished insulin production after CVB infection of β-cells, resulting in diabetes.

negative: Reconstitution of the immune system after hematopoietic stem cell transplantation in humans Hematopoietic stem cell transplantation is associated with a severe immune deficiency. As a result, the patient is at high risk of infections. Innate immunity, including epithelial barriers, monocytes, granulocytes, and NK cells recovers within weeks after transplantation. By contrast, adaptive immunity recovers much slower. B- and T-cell counts normalize during the first months after transplantation, but in particular, T-cell immunity may remain impaired for years. During the last decade, much of the underlying mechanisms have been identified. These insights may provide new therapies to accelerate recovery.

negative: DNA methylation is a critical cell-intrinsic determinant of astrocyte differentiation in the fetal brain. Astrocyte differentiation, which occurs late in brain development, is largely dependent on the activation of a transcription factor, STAT3. We show that astrocytes, as judged by glial fibrillary acidic protein (GFAP) expression, never emerge from neuroepithelial cells on embryonic day (E) 11.5 even when STAT3 is activated, in contrast to E14.5 neuroepithelial cells. A CpG dinucleotide within a STAT3 binding element in the GFAP promoter is highly methylated in E11.5 neuroepithelial cells, but is demethylated in cells responsive to the STAT3 activation signal to express GFAP. This CpG methylation leads to inaccessibility of STAT3 to the binding element. We suggest that methylation of a cell type-specific gene promoter is a pivotal event in regulating lineage specification in the developing brain.

negative: Recovery of visual response of injured adult rat optic nerves treated with transglutaminase. Failure of axons of the central nervous system in adult mammals to regenerate spontaneously after injury is attributed in part to inhibitory molecules associated with oligodendrocytes. Regeneration of central nervous system axons in fish is correlated with the presence of a transglutaminase. This enzyme dimerizes interleukin-2, and the product is cytotoxic to oligodendrocytes in vitro. Application of this nerve-derived transglutaminase to rat optic nerves, in which the injury had caused the loss of visual evoked potential response to light, promoted the recovery of that response within 6 weeks after injury. Transmission electron microscopy analysis revealed the concomitant appearance of axons in the distal stump of the optic nerve.

negative: MHC Haplotype Matching for Unrelated Hematopoietic Cell Transplantation Background  Current criteria for the selection of unrelated donors for hematopoietic cell transplantation (HCT) include matching for the alleles of each human leukocyte antigen (HLA) locus within the major histocompatibility complex (MHC). Graft-versus-host disease (GVHD), however, remains a significant and potentially life-threatening complication even after HLA-identical unrelated HCT. The MHC harbors more than 400 genes, but the total number of transplantation antigens is unknown. Genes that influence transplantation outcome could be identified by using linkage disequilibrium (LD)-mapping approaches, if the extended MHC haplotypes of the unrelated donor and recipient could be defined.

negative: Mechanisms of astrocytogenesis in the mammalian brain. In the mammalian central nervous system, astrocytes are the most abundant cell type and play crucial roles in brain development and function. Astrocytes are known to be produced from multipotent neural stem cells (NSCs) at the late gestational stage during brain development, and accumulating evidence indicates that this stage-dependent generation of astrocytes from NSCs is achieved by systematic cooperation between environmental cues and cell-intrinsic programs. Exemplifying the former is cytokine signaling through the gp130-Janus kinase/signal transducer and activator of transcription 3 pathway, and exemplifying the latter is epigenetic modification of astrocyte-specific genes. Here, we introduce recent advances in our understanding of the mechanisms that coordinate astrocytogenesis from NSCs by modulating signaling pathways and epigenetic programs, with a particular focus on the developing mammalian forebrain.

negative: Glycolytic oligodendrocytes maintain myelin and long-term axonal integrity Oligodendrocytes, the myelin-forming glial cells of the central nervous system, maintain long-term axonal integrity. However, the underlying support mechanisms are not understood. Here we identify a metabolic component of axon–glia interactions by generating conditional Cox10 (protoheme IX farnesyltransferase) mutant mice, in which oligodendrocytes and Schwann cells fail to assemble stable mitochondrial cytochrome c oxidase (COX, also known as mitochondrial complex IV). In the peripheral nervous system, Cox10 conditional mutants exhibit severe neuropathy with dysmyelination, abnormal Remak bundles, muscle atrophy and paralysis. Notably, perturbing mitochondrial respiration did not cause glial cell death. In the adult central nervous system, we found no signs of demyelination, axonal degeneration or secondary inflammation. Unlike cultured oligodendrocytes, which are sensitive to COX inhibitors, post-myelination oligodendrocytes survive well in the absence of COX activity. More importantly, by in vivo magnetic resonance spectroscopy, brain lactate concentrations in mutants were increased compared with controls, but were detectable only in mice exposed to volatile anaesthetics. This indicates that aerobic glycolysis products derived from oligodendrocytes are rapidly metabolized within white matter tracts. Because myelinated axons can use lactate when energy-deprived, our findings suggest a model in which axon–glia metabolic coupling serves a physiological function.

negative: Inducible caspase-9 suicide gene controls adverse effects from alloreplete T cells after haploidentical stem cell transplantation. To test the feasibility of a single T-cell manipulation to eliminate alloreactivity while sparing antiviral and antitumor T cells, we infused 12 haploidentical hematopoietic stem cell transplant patients with increasing numbers of alloreplete haploidentical T cells expressing the inducible caspase 9 suicide gene (iC9-T cells). We determined whether the iC9-T cells produced immune reconstitution and if any resultant graft-versus-host disease (GVHD) could be controlled by administration of a chemical inducer of dimerization (CID; AP1903/Rimiducid). All patients receiving >10(4) alloreplete iC9-T lymphocytes per kilogram achieved rapid reconstitution of immune responses toward 5 major pathogenic viruses and concomitant control of active infections. Four patients received a single AP1903 dose. CID infusion eliminated 85% to 95% of circulating CD3(+)CD19(+) T cells within 30 minutes, with no recurrence of GVHD within 90 days. In one patient, symptoms and signs of GVHD-associated cytokine release syndrome (CRS-hyperpyrexia, high levels of proinflammatory cytokines, and rash) resolved within 2 hours of AP1903 infusion. One patient with varicella zoster virus meningitis and acute GVHD had iC9-T cells present in the cerebrospinal fluid, which were reduced by >90% after CID. Notably, virus-specific T cells recovered even after AP1903 administration and continued to protect against infection. Hence, alloreplete iC9-T cells can reconstitute immunity posttransplant and administration of CID can eliminate them from both peripheral blood and the central nervous system (CNS), leading to rapid resolution of GVHD and CRS. The approach may therefore be useful for the rapid and effective treatment of toxicities associated with infusion of engineered T lymphocytes. This trial was registered at www.clinicaltrials.gov as #NCT01494103.

negative: Self-assembling peptides optimize the post-traumatic milieu and synergistically enhance the effects of neural stem cell therapy after cervical spinal cord injury. INTRODUCTION The hostile environment after spinal cord injury (SCI) can compromise effects of regenerative therapies. We hypothesized that optimizing the post-traumatic environment with QL6 self-assembling peptides (SAPs) before neural precursor cell (NPC) transplantation would improve cell survival, differentiation and functional recovery. METHODS A total of 90 Wistar rats received a clip-compression SCI at C7. Within each of two study arms, animals were randomized into 5 groups (NPC, SAP, NPC+SAP, vehicle, and sham). SAPs and NPCs were injected into the spinal cord 1day and 14days post-injury, respectively. Animals received growth factors over 7days and were immunosuppressed. Rats were sacrificed at 4weeks and sections of the cervical spinal cord prepared for immunohistochemistry (first study arm). Neurological function was assessed weekly for 8weeks using a battery of behavioral tests. Nine weeks post-SCI, the corticospinal tract was assessed using fiber-tracking (second arm). RESULTS SAP-treated animals had significantly more surviving NPCs which showed increased differentiation to neurons and oligodendrocytes compared to controls. SAPs alone or in combination with NPCs resulted in smaller intramedullary cysts and larger volume of preserved tissue compared to other groups. The combined treatment group showed reduced astrogliosis and chondroitin sulfate proteoglycan deposition. Synaptic connectivity was increased in the NPC and combined treatment groups. Corticospinal tract preservation and behavioral outcomes improved with combinatorial treatment. CONCLUSION Injecting SAPs after SCI enhances subsequent NPC survival, integration and differentiation and improves functional recovery. STATEMENT OF SIGNIFICANCE The hostile environment after spinal cord injury (SCI) can compromise effects of regenerative therapies. We hypothesized that improving this environment with self-assembling peptides (SAPs) before neural precursor cell (NPC) transplantation would support their beneficial effects. SAPs assemble once injected, providing a supportive scaffold for repair and regeneration. We investigated this in a rat model of spinal cord injury. More NPCs survived in SAP-treated animals and these showed increased differentiation compared to controls. SAPS alone or in combination with NPCs resulted in smaller cysts and larger volume of preserved tissue with the combined treatment also reducing scarring and improving behavioral outcomes. Overall, injection of SAPs was shown to improve the efficacy of NPC treatment, a promising finding for those with SCIs.

negative: Endogenous bone marrow MSCs are dynamic, fate-restricted participants in bone maintenance and regeneration. Mesenchymal stem cells (MSCs) commonly defined by in vitro functions have entered clinical application despite little definition of their function in residence. Here, we report genetic pulse-chase experiments that define osteoblastic cells as short-lived and nonreplicative, requiring replenishment from bone-marrow-derived, Mx1(+) stromal cells with "MSC" features. These cells respond to tissue stress and migrate to sites of injury, supplying new osteoblasts during fracture healing. Single cell transplantation yielded progeny that both preserve progenitor function and differentiate into osteoblasts, producing new bone. They are capable of local and systemic translocation and serial transplantation. While these cells meet current definitions of MSCs in vitro, they are osteolineage restricted in vivo in growing and adult animals. Therefore, bone-marrow-derived MSCs may be a heterogeneous population with the Mx1(+) population, representing a highly dynamic and stress responsive stem/progenitor cell population of fate-restricted potential that feeds the high cell replacement demands of the adult skeleton.

negative: Excitotoxic brain injury in adult zebrafish stimulates neurogenesis and long-distance neuronal integration. Zebrafish maintain a greater capacity than mammals for central nervous system repair after injury. Understanding differences in regenerative responses between different vertebrate species may shed light on mechanisms to improve repair in humans. Quinolinic acid is an excitotoxin that has been used to induce brain injury in rodents for modeling Huntington's disease and stroke. When injected into the adult rodent striatum, this toxin stimulates subventricular zone neurogenesis and neuroblast migration to injury. However, most new neurons fail to survive and lesion repair is minimal. We used quinolinic acid to lesion the adult zebrafish telencephalon to study reparative processes. We also used conditional transgenic lineage mapping of adult radial glial stem cells to explore survival and integration of neurons generated after injury. Telencephalic lesioning with quinolinic acid, and to a lesser extent vehicle injection, produced cell death, microglial infiltration, increased cell proliferation, and enhanced neurogenesis in the injured hemisphere. Lesion repair was more complete with quinolinic acid injection than after vehicle injection. Fate mapping of her4-expressing radial glia showed injury-induced expansion of radial glial stem cells that gave rise to neurons which migrated to injury, survived at least 8 weeks and formed long-distance projections that crossed the anterior commissure and synapsed in the contralateral hemisphere. These findings suggest that quinolinic acid lesioning of the zebrafish brain stimulates adult neural stem cells to produce robust regeneration with long-distance integration of new neurons. This model should prove useful for elucidating reparative mechanisms that can be applied to restorative therapies for mammalian brain injury.

negative: Cytomegalovirus US2 destroys two components of the MHC class II pathway, preventing recognition by CD4+ T cells Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus that causes life-threatening disease in patients who are immunosuppressed for bone marrow or tissue transplantation or who have AIDS (ref. 1). HCMV establishes lifelong latent infections and, after periodic reactivation from latency, uses a panel of immune evasion proteins to survive and replicate in the face of robust, fully primed host immunity. Monocyte/macrophages are important host cells for HCMV, serving as a latent reservoir and as a means of dissemination throughout the body. Macrophages and other HCMV-permissive cells, such as endothelial and glial cells, can express MHC class II proteins and present antigens to CD4+ T lymphocytes. Here, we show that the HCMV protein US2 causes degradation of two essential proteins in the MHC class II antigen presentation pathway: HLA-DR-α and DM-α. This was unexpected, as US2 has been shown to cause degradation of MHC class I (refs. 5,6), which has only limited homology with class II proteins. Expression of US2 in cells reduced or abolished their ability to present antigen to CD4+ T lymphocytes. Thus, US2 may allow HCMV-infected macrophages to remain relatively 'invisible' to CD4+ T cells, a property that would be important after virus reactivation.

negative: A JOURNAL OF NEUROLOGY Brain glial cells, five times more prevalent than neurons, have recently received attention for their potential involvement in epileptic seizures. Microglia and astrocytes, associated with inflammatory innate immune responses, are responsible for surveillance of brain damage that frequently results in seizures. Thus, an intriguing suggestion has been put forward that seizures may be facilitated and perhaps triggered by brain immune responses. Indeed, recent evidence strongly implicates innate immune responses in lowering seizure threshold in experimental models of epilepsy, yet, there is no proof that they can play an independent role in initiating seizures in vivo. Here, we show that cortical innate immune responses alone produce profound increases of brain excitability resulting in focal seizures. We found that cortical application of lipopolysaccharide, binding to toll-like receptor 4 (TLR4), triples evoked field potential amplitudes and produces focal epileptiform discharges. These effects are prevented by pre-application of interleukin-1 receptor antagonist. Our results demonstrate how the innate immune response may participate in acute seizures, increasing neuronal excitability through interleukin-1 release in response to TLR4 detection of the danger signals associated with infections of the central nervous system and with brain injury. These results suggest an important role of innate immunity in epileptogenesis and focus on glial inhibition, through pharmacological blockade of TLR4 and the pro-inflammatory mediators released by activated glia, in the study and treatment of seizure disorders in humans.

negative: Turning blood into brain: cells bearing neuronal antigens generated in vivo from bone marrow. Bone marrow stem cells give rise to a variety of hematopoietic lineages and repopulate the blood throughout adult life. We show that, in a strain of mice incapable of developing cells of the myeloid and lymphoid lineages, transplanted adult bone marrow cells migrated into the brain and differentiated into cells that expressed neuron-specific antigens. These findings raise the possibility that bone marrow-derived cells may provide an alternative source of neurons in patients with neurodegenerative diseases or central nervous system injury.

negative: Cardiac neural crest cells contribute to the dormant multipotent stem cell in the mammalian heart Arodent cardiac side population cell fraction formed clonal spheroids in serum-free medium, which expressed nestin, Musashi-1, and multi-drug resistance transporter gene 1, markers of undifferentiated neural precursor cells. These markers were lost following differentiation, and were replaced by the expression of neuron-, glial-, smooth muscle cell–, or cardiomyocyte-specific proteins. Cardiosphere-derived cells transplanted into chick embryos migrated to the truncus arteriosus and cardiac outflow tract and contributed to dorsal root ganglia, spinal nerves, and aortic smooth muscle cells. Lineage studies using double transgenic mice encoding protein 0–Cre/Floxed-EGFP revealed undifferentiated and differentiated neural crest-derived cells in the fetal myocardium. Undifferentiated cells expressed GATA-binding protein 4 and nestin, but not actinin, whereas the differentiated cells were identified as cardiomyocytes. These results suggest that cardiac neural crest-derived cells migrate into the heart, remain there as dormant multipotent stem cells—and under the right conditions—differentiate into cardiomyocytes and typical neural crest-derived cells, including neurons, glia, and smooth muscle.

negative: CNS repair requires both effector and regulatory T cells with distinct temporal and spatial profiles. Monocyte-derived macrophages (mo-MΦs) and T cells have been shown to contribute to spinal cord repair. Recently, the remote brain choroid plexus epithelium (CP) was identified as a portal for monocyte recruitment, and its activation for leukocyte trafficking was found to be IFN-γ-dependent. Here, we addressed how the need for effector T cells can be reconciled with the role of inflammation-resolving immune cells in the repair process. Using an acute spinal cord injury model, we show that in mice deficient in IFN-γ-producing T cells, the CP was not activated, and recruitment of inflammation-resolving mo-MΦ to the spinal cord parenchyma was limited. We further demonstrate that mo-MΦ locally regulated recruitment of thymic-derived Foxp3(+) regulatory T (Treg) cells to the injured spinal cord parenchyma at the subacute/chronic phase. Importantly, an ablation protocol that resulted in reduced Tregs at this stage interfered with tissue remodeling, in contrast to Treg transient ablation, restricted to the 4 d period before the injury, which favored repair. The enhanced functional recovery observed following such a controlled decrease of Tregs suggests that reduced systemic immunosuppression at the time of the insult can enhance CNS repair. Overall, our data highlight a dynamic immune cell network needed for repair, acting in discrete compartments and stages, and involving effector and regulatory T cells, interconnected by mo-MΦ. Any of these populations may be detrimental to the repair process if their level or activity become dysregulated. Accordingly, therapeutic interventions must be both temporally and spatially controlled.

negative: Islet-Like Clusters Derived from Mesenchymal Stem Cells in Wharton's Jelly of the Human Umbilical Cord for Transplantation to Control Type 1 Diabetes BACKGROUND There is a widespread interest in developing renewable sources of islet-replacement tissue for type I diabetes mellitus. Human mesenchymal cells isolated from the Wharton's jelly of the umbilical cord (HUMSCs), which can be easily obtained and processed compared with embryonic and bone marrow stem cells, possess stem cell properties. HUMSCs may be a valuable source for the generation of islets. METHODOLOGY AND PRINCIPAL FINDINGS HUMSCs were induced to transform into islet-like cell clusters in vitro through stepwise culturing in neuron-conditioned medium. To assess the functional stability of the islet-like cell clusters in vivo, these cell clusters were transplanted into the liver of streptozotocin-induced diabetic rats via laparotomy. Glucose tolerance was measured on week 12 after transplantation accompanied with immunohistochemistry and electron microscopy analysis. These islet-like cell clusters were shown to contain human C-peptide and release human insulin in response to physiological glucose levels. Real-time RT-PCR detected the expressions of insulin and other pancreatic beta-cell-related genes (Pdx1, Hlxb9, Nkx2.2, Nkx6.1, and Glut-2) in these islet-like cell clusters. The hyperglycemia and glucose intolerance in streptozotocin-induced diabetic rats was significantly alleviated after xenotransplantation of islet-like cell clusters, without the use of immunosuppressants. In addition to the existence of islet-like cell clusters in the liver, some special fused liver cells were also found, which characterized by human insulin and nuclei-positive staining and possessing secretory granules. CONCLUSIONS AND SIGNIFICANCE In this study, we successfully differentiate HUMSCs into mature islet-like cell clusters, and these islet-like cell clusters possess insulin-producing ability in vitro and in vivo. HUMSCs in Wharton's Jelly of the umbilical cord seem to be the preferential source of stem cells to convert into insulin-producing cells, because of the large potential donor pool, its rapid availability, no risk of discomfort for the donor, and low risk of rejection.

negative: Identification of human brain tumour initiating cells The cancer stem cell (CSC) hypothesis suggests that neoplastic clones are maintained exclusively by a rare fraction of cells with stem cell properties. Although the existence of CSCs in human leukaemia is established, little evidence exists for CSCs in solid tumours, except for breast cancer. Recently, we prospectively isolated a CD133+ cell subpopulation from human brain tumours that exhibited stem cell properties in vitro. However, the true measures of CSCs are their capacity for self renewal and exact recapitulation of the original tumour. Here we report the development of a xenograft assay that identified human brain tumour initiating cells that initiate tumours in vivo. Only the CD133+ brain tumour fraction contains cells that are capable of tumour initiation in NOD-SCID (non-obese diabetic, severe combined immunodeficient) mouse brains. Injection of as few as 100 CD133+ cells produced a tumour that could be serially transplanted and was a phenocopy of the patient's original tumour, whereas injection of 105 CD133- cells engrafted but did not cause a tumour. Thus, the identification of brain tumour initiating cells provides insights into human brain tumour pathogenesis, giving strong support for the CSC hypothesis as the basis for many solid tumours, and establishes a previously unidentified cellular target for more effective cancer therapies.

negative: Leptin regulates glutamate and glucose transporters in hypothalamic astrocytes. Glial cells perform critical functions that alter the metabolism and activity of neurons, and there is increasing interest in their role in appetite and energy balance. Leptin, a key regulator of appetite and metabolism, has previously been reported to influence glial structural proteins and morphology. Here, we demonstrate that metabolic status and leptin also modify astrocyte-specific glutamate and glucose transporters, indicating that metabolic signals influence synaptic efficacy and glucose uptake and, ultimately, neuronal function. We found that basal and glucose-stimulated electrical activity of hypothalamic proopiomelanocortin (POMC) neurons in mice were altered in the offspring of mothers fed a high-fat diet. In adulthood, increased body weight and fasting also altered the expression of glucose and glutamate transporters. These results demonstrate that whole-organism metabolism alters hypothalamic glial cell activity and suggest that these cells play an important role in the pathology of obesity.