Difference in the indices of adipose tissue and peripheral blood cells of individuals with overweight

Abstract

Background:Overweight is one of the predisposing risk factors for the development of different diseases, pathogenesis of which is grounded on the various types of disturbances of the adipose tissue structure, impeding both local and systemic metabolism. Recent experimental and clinical studies have revealed a new phenomenon: overweight leads to inflammation of adipose tissue and dynamically acts on the peripheral blood monocytes. In this correlation, the utmost importance is given to macrophages of the white adipose tissue (WAT) and monocytes, which account for not only the necrosis of adipocytes and utilization of the cellular debris, but also to the formation and persistence of the chronic inflammation sites.

Aim of the study: To identify the dynamic morphologic changes in adipose tissue in individuals with overweight and with different degrees of obesity, taking into account the ability of leptin to activate PMNs; find out the correlation between the altered level of inflammation, plasma levels of leptin and changes of cells in peripheral blood, monocytes/tissue macrophages and PMNs; perform the quantitative assessment of the data.

Methods: puncture biopsy samples from the gluteal area white adipose tissue and 2 ml. of venous blood samples were collected from male (n=14) and female patients (n=11) with age ranging in 41.5±12.3 years (mean ± SD), receiving treatment for overweight and increased body mass. The body mass index (BMI) was calculated by Quetelet index: BMI = body weight (kg) / height² (m). The patients were classified depending on BMI according to the degree of obesity (WHO, 1997).

The leptin was measured in the blood serum by immunoenzyme method using the reagents kit (“Leptin (Sandwich) ELISA”, DRG Instruments GmbH, Germany). Histological and Electron microscopic methods were used.

Results and conclusion. Based on the given data, statistically significant differences were obtained in all studied parameters between group I (normal weight + overweight) and group II (I, II and III degree obesity) (t-criterion of Student and U-criterion of Mann-Whitney) (Table 2a, 2b, 3).

The state of monocytes/ macrophages and peripheral blood cells reflects not so significantly obvious changes on the body weight, increased production and utilization of leptin activates the recruitment of macrophages from peripheral blood, simultaneously promoting their phagocytic function, which eventually leads to lipophagocytosis, necrosis and build-up of cellular debris with repeated activation of macrophages. Consequently, the interrelation between increased production of leptin, breakdown of adipocytes from WAT and characteristic reaction of monocytes and macrophages on increased body weight represents the cause for persisting sites of necrosis in adipose tissue and formation of chronic inflammatory response, supporting to remodeling of adipocytes and progression of derangements in fat metabolism from increased body weight to different degrees of obesity, having at the same time the important diagnostic and prognostic potential.