Gene Polymorphisms Predicting High Plasma: A Study in Centenarians

P.M. Mannucci, D. Mari, G. Merati, F. Peyvandi, L. Tagliabue, E. Sacchi, E. Taioli, P. Sansoni, S. Bertolini, C. Franceschi

Abstract:
Gene polymorphisms associated with the plasma levels of fibrinogen, factor VII, and plasminogen activator inhibitor 1 (PAI-1), hemostasis proteins that help to predict the risk of atherothrombotic disease, were compared in 124 healthy individuals > 100 years old and 130 young, healthy individuals to identify genetic influences on extreme longevity. We investigated the restriction fragment length polymorphism G/A "455 located in the promoter of the p-fibrinogen gene, the guanine insertion/deletion polymorphism 4G/5G in the promoter of the PAI-1 gene, and the R353Q substitution polymorphism in exon 8 of the factor VII gene. Alleles and genotypes associated with elevated plasma levels of fibrinogen and factor VII were found with similar frequencies in centenarians and in the comparison group. However, in centenarians, there was a significantly higher frequency of the 4G allele and of the homozygous 4G4G genotype associated with high PAI-1 levels. Since high PAI-1 is considered a predictor of recurrent myocardial infarction in young men, it is intriguing that the corresponding genetic marker is more frequent in centenarians who have escaped major age-related atherothrombotic disease and reached the extreme limits of human life. Homozygosity for the 4G allele, despite its association with impaired fibrinolysis, is compatible with successful aging. (Arterioscler Thromb Vase Biol. 1997;17:755-759.)

Keywords: 
centenarians, fibrinogen, factor VII, plasminogen activator inhibitor 1, gene polymorphisms

The purpose of this study was to evaluate the allele and genotype frequencies of polymorphisms influencing plasma levels of fibrinogen, factor VII, and PAI-1 in a cohort of Italian healthy centenarians, who are considered a natural model of extreme longevity and positive selection. Results obtained in these exceptional individuals, who have escaped age-related atherothrombotic disease and reached the extreme limits of life, were compared with those obtained in healthy individuals who were young enough that none of them would be lost from the study sample because of symptomatic atherothrombotic disease. We surmised that the study of genetic markers of hypercoagulability and hypofibrinolysis should establish whether or not successful aging is associated with the predominance of genotypes predicting lower plasma levels of hemostasis proteins.

From http://ahajournals.org by on March 13, 2020

Common biallelic polymorphisms of the genes encoding for fibrinogen, factor VII, and PAI-1 influence the plasma levels of these proteins. The polymorphic genotypes associated with elevated plasma levels of these hemostasis components might prove more reliable as predictors of the thrombotic risk than the plasma levels. In the general population, plasma levels have a continuous distribution, and so it is difficult to establish cutoff values that can identify the individuals at risk. In addition, variation of plasma levels determined by environmental factors may further complicate risk assignment. To assess the value of genetic markers as risk predictors, studies have been carried out in relatively small groups of individuals with or without atherothrombotic disease, but the results have been conflicting.

Methods:
Subjects
In Italy, there is currently a multicenter project on centenarians; it is coordinated by one of the authors (C.F.). The aim of this project is to study the mechanisms of successful aging. Centenarians identified from the General Registry Offices are studied in special units, generally established in university departments. Approximately 2000 centenarians have been identified. Several biological systems of these individuals are being investigated by biochemical and molecular methods.

Received April 16, 1995; revision accepted July 31, 1996. From the Angelo Bianchi Bonomi Hemophilia and Center, Epidemiology Unit, IRCCS Maggiore Hospital and Unit, Institute of Internal Medicine, University of Milano D.M., G.M., F.P., L.T., E.S., E.T.); the Institute of Clinical Medicine, University of Parma (P.S.); the Department of Medicine, University of Genoa (S.B.); and the Department of Biochemical Sciences, University of Modena (C.F.), Italy.

Received April , ; revision accepted July , From the Angelo Bianchi Bonomi Hemophilia and Thrombosis CenterSolution (0.1% Ficoll 400, 0.1% polyvinylpyrrolidone, 0.1% BSA), 100 ng/mL salmon sperm DNA, and 0.5% SDS were combined. Then, the labeled probes were added separately to each solution at a final concentration of 105 cpm/mL for at least 1 hour. Membranes were washed in 5x SSC and 0.1% SDS for several minutes to remove background hybridization. Prehybridization, hybridization, and washing were carried out at 55°C for the oligonucleotide complementary to the 4G allele and at 58°C for the oligonucleotide complementary to the 5G allele. Autoradiograms were obtained by exposing films to membranes intensifying screens for 16 to 20 hours at -70°C. Samples from individuals with known genotypes, determined by allele-specific oligonucleotide melting14 and kindly supplied by S. (London, UK), were used as controls. The young individuals (82 women and 48 men) were all under 31 years old (mean age, 25.3 ± 7 years; range, 14 to 30 years) and were randomly selected from the same metropolitan communities (hospital staff, high-school students). Arterial or venous thrombotic disease was excluded based on clinical history and physical examination results. None of them were current or recent smokers. Blood samples for DNA analysis were drawn directly into vacuum containers containing sodium citrate as anticoagulant. Genomic DNA was prepared from whole blood using a salting-out procedure." from http://ahajournals.org on March 13, 2020.