The steady increase in the number of patients with abnormal uterine bleeding (AUB) has a negative impact on a woman's reproductive health. Obesity is defined as one of the risk factors for AUB and its role in the development of AUB-M and AUB-O has been studied to date. However, our earlier analysis of the results of histological examination of endometrial biopsies showed that in obese women with AUB, the desquamation phase (AUB-E) is significantly more common in the endometrium than in normal-weight women. One of the possible pathogenetic mechanisms may be abnormal endometrial vascularization due to systemic proinflammatory status and local tissue hypoxia. Aim. To identify the features of the expression of endothelial markers CD34+ and eNOS in endometrial biopsies of patients with AUB and obesity and their role in the pathogenesis of endometrial dysfunction. Materials and methods. A prospective randomized cohort study included 40 patients of reproductive age with AUB-E. Depending on the presence of obesity, women were stratified into 2 groups: 20 patients with AUB-E and obesity (group 1) and 20 normal-weight patients with AUB-E (group 2). 10 healthy women of reproductive age were included as a control group. All patients underwent endometrial biopsy followed by histological examination according to the standard procedure. At the second stage, an immunohistochemical study of CD34+ and eNOS angiogenesis markers was performed using monoclonal mouse antibodies in standard dilution. The IBM SPSS Statistics v.26 program (IBM Corporation, USA) was used for statistical data analysis. Results. CD34+ expression in patients with AUB and obesity was significantly higher than in normal-weight patients with AUB and healthy women (2,5±0,2, respectively; 95% CI 2,1–2,8 vs. 1,8±0,2; 95% CI 1,5–2,2 and 0,5±0,1; 95% CI 0,4–0,6; p1-2=0,03; p1-3<0,001; p2-3<0,001), as well as eNOS expression (respectively 8,7±0,6; 95% CI 7,3–10,0 vs. 4,0±0,5; 95% CI 3–5 and 1,3±0,2; 95% CI 0,9–1,7; p1-2<0,001; p1-3<0,001; p2-3<0,001). Conclusion. Patients with AUB-E and obesity are characterized by increased expression of CD34+ and eNOS in endometrial tissue, which indicates pathological activation of neoangigenesis. Perhaps one of the mechanisms of pathogenesis is the formation of a proinflammatory profile against the background of obesity, which contributes to the pathological hypervascularization of the endometrium. Effective weight loss measures can probably reduce the incidence and recurrence of AUB-E.
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