#1227 The role of P-selectin (CD62P) expression in renal tissue in the development of diabetic nephropathy

Abstract

Abstract Background and Aims The prevalence of diabetic nephropathy (DN) is increasing in line with the increase in the incidence of diabetes mellitus (DM) worldwide. The latest data from the International Diabetes Federation (IDF) predicts that by 2045, more than 10.5% of adults worldwide will have diabetes. This will lead to kidney damage in 100-250 million people. DN is characterized by structural and functional changes. As a result of chronic hyperglycemia, pathogenic changes in the vascular wall develop, and the frequency of micro- and macrovascular complications associated with morbidity and mortality among patients with diabetes increases. However, the exact mechanism of vascular complications is not completely clear. Endothelial dysfunction plays a key role in triggering the development of inflammatory mechanisms that are associated with vascular complications in patients with type 2 diabetes mellitus (T2DM). Activation of the endothelium due to increased release of cytokines and expression of adhesion molecules promotes platelet activation and their adhesion to the activated endothelium. Selectins (E-selectin, L-selectin and P-selectin) play a major role in the development of microvascular complications. The aim of the study was to examine the role of P-selectin (CD62p) expression in the glomerular endothelium and peritubular capillaries in patients with different morphological classes of DN and to evaluate its effect on the development and progression of morphological changes in renal tissue. Method Was examined 49 patients with T2DM complicated by the development of DN. The average age of the patients was 66.58 ± 3.27 years. There were 35 women, 14 men. The duration of the disease was 17.70 ± 0.35 years. The duration of DN from the moment of detection of microalbuminuria to the morphological examination of the renal tissue and diagnosis was 1.65 ± 0.34 years. All patients underwent light and immunofluorescence microscopy of kidney tissue biopsies obtained by intravital puncture biopsy. Morphological changes in tissue were assessed in accordance with the latest international classification of diabetic nephropathy developed by the Scientific Committee of the Pathology Society, USA. According to light microscopy data, class IIa (mild mesangial expansion) was detected in 12 patients, class IIb (severe mesangial expansion) in 14 patients, class III (Kimmelstil–Wilson nodular lesions) in 19 patients, and class IV (advanced diabetic glomerulosclerosis) in 5 patients. In addition to light microscopy, the expression of CD62β (P-selectin) in the glomerular endothelium and in peritubular capillaries was determined in all patients. FITc-labeled monoclonal antibodies (FITC anti-human CD62p Antibody, clone AK4 Cat#304904), were used (Biolegend, USA). Results Analysis of biopsy tissue from DN patients showed that CD62p expression is detected both in the glomerular endothelium (1.6383 ± 0.4789 (95% CI: 0.9574-2.7234)) and in peritubular capillaries (1.1702 ± 0.1308 (95% CI: 0.9149–1.4250)). Using the linear regression method with the calculation of the coefficients of determination R2 (R Square), the values of the F criterion, significant regression models were obtained: Expression of CD62p in the glomerular endothelium promotes the development and progression of arteriolar hyalinosis (R2=0.213, F=12.476 p=0.001); expansion of the mesangial matrix (R2=0.362, F=26.09, p=0.0001); thickening of the basement membrane (R2=0.127, F=6.57, p=0.014); development and progression of nodular Kimmelstiel–Wilson lesions (R2=0.106, F=5.360, p=0.025). Expression of CD62p in peritubular capillaries promotes the development of interstitial sclerosis (R2=0.549, F=54.732, p=0.0001). The severity of CD62p expression in the glomerular endothelium depends on the morphological class of DN in patients (R2=0.216, F=12.684, p=0.001). Conclusion