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.
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.
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)