Intrapancreatic Adipose Tissue Of Nondiabetic And Type 2 Diabetic Subjects And Relationships With Islet Morphometry

Little information is available on adipose tissue features in the human pancreas (AdTP). In the present study we performed morphologic and morphometric studies on AdTP of 9 overweight/obese nondiabetic (ND, age: 65±5 years; 4M/5F; BMI: 31.3±0.4 Kg/m2, mean±SEM) and 13 matched type 2 diabetic (T2D, age: 70±2 years, 8M/5F; BMI: 30.0±0.8 kg/m2) organ donors. Adipocytes were identified and quantified on a fluorescence DM5500 Leica microscope, using the MetaMorph v 1.8.0 software with a tresholded mask applied in exclusive mode. Macrophages were identified by immunohistochemistry using anti-CD68 (Dako) antibody. Assessment of insulin (Abcam Ab) and glucagon (Sigma Ab) positive cells was also performed. The number of adipocytes trended higher (+32.8%) in T2D (8.9±1.4/mm2) compared to ND (6.7±2.1/mm2) and their size was greater in T2D (9,319±1,028 μm2) than ND (5,639±639 μm2, p=0.01). AdTP area in relation to acinar tissue was 90.4% higher (p=0.07) in T2D (7.6±1.3%) than ND (3.9±1.5%). The amount of adipocytes with adjacent ≥ 3 CD68+ cells was higher (p=0.048) in T2D (31/281, 11%) than ND (7/147, 5%). Insulin positive area (T2D: 0.49±0.06%; ND: 0.55±0.09%) as well as glucagon positive area (T2D: 0.24±0.03%; ND: 0.32±0.07%) did not differ significantly between the two groups. Adipocyte size was negatively associated with islet number in ND+T2D (p=0.06) and positively with insulin area in ND (p=0.058); there was a significant, positive relationship between the amount of adipocytes and the number of islets in T2D (p=0.017). In conclusion, we found significant differences in the AdTP of T2D as compared to ND, including increased adypocite size and presence of adipocyte adjacent CD68+ cells; some of these parameters correlated with islet morphometric indices. Disclosure M. Suleiman: None. C. De Luca: None. P. De Simone: None. U. Boggi: None. F. Grano: None. M. Bugliani: None. P. Marchetti: None. L. Marselli: None. Funding Innovative Medicines Initiative 2 Joint Undertaking (115881); European Union; European Federation of Pharmaceutical Industries and Associations; Swiss State Secretariat for Education, Research and Innovation (16.0097-2)