PMC7160728_01
(a) Glucose (black circles) and total GLP-1 (red dashed lines) plasma levels (measured by Mercodia AB, Uppsala, Sweden (assay # 10-1278-01) of the patient during a standardized mixed-meal test 300 ml Ensure plus , Abbott, containing 60 g carbohydrates). The patient developed symptomatic hypoglycaemia at a timepoint of 120 min (2.5 mmol/l) requiring intravenous glucose administration with immediate resolution of symptoms. (b) Representative 68Ga-DOTA-Exendin-4 PET/CT image of the patient with a large and strong tracer accumulation (SUVmax 10) in pars 2 duodenii (white arrow). (c) Haematoxylin and eosin staining of a representative duodenal biopsy at 100x resolution showing hyperplastic Brunner's glands with (d) GLP-1 receptor immunostaining of Brunner's glands (membranous distribution) and (e) negative immunostaining for insulin each at 200x resolution. All staining was performed with a respective positive control (data not shown).
CRIE2020-4510910.001.jpg
PMC7160728_01_CRIE2020-4510910.001.jpg
fig1
A mixed-meal test (300 ml Ensure plus ) containing 60 g of carbohydrates after a 10-hour fasting period confirmed symptomatic postprandial hypoglycaemia (sweating, drowsiness, odd behaviour, and incoordination) at a glucose level of 2.5 mmol/l, and intravenous glucose administration was required for immediate remission of symptoms (Figure 1(a)). Therein, the pancreas showed a homogeneous signal distribution (SUV 5.7-8.3), but intensive uptake in the first and second part of the duodenum (SUVmax of 10.0) was observed (Figure 1(b)). Histologically, there were no signs of malignancy or inflammation (Figure 1(c)). Representative biopsies of the pars 2 duodenii showed normal mucosa with hyperplastic Brunner's glands, which were strongly positive for the GLP-1 receptor on immunohistochemistry but negative for insulin (Figures 1(d) and 1(e)).