Leptin in very old and long-living patients with coronary artery disease

BACKGROUND. Leptin is involved in the development of some age-related pathological conditions, in particular, metabolic syndrome, obesity, diabetes mellitus and atherosclerosis. Considering the population aging and high prevalence of cardiovascular diseases and related mortality in the older age group, it is quite important to study various risk factors for cardiovascular pathology (including hyperleptinemia) in the very old and long-living population.

AIM. To determine the concentration of leptin and to analyze the relationships of this adipokine with obesity and a number of other pathological conditions in very old and long-living patients with coronary artery disease (CAD).

MATERIALS AND METHODS. This work was a cross-sectional study. A total of 110 very old patients were enrolled in the study: 90 patients with CAD in the study group and20 patients without CAD in the control group. Mean age of the patients was 88.5 + 4.5 years; 48.2% of patients were ≥ 90 years. The serum leptin concentration was determined by enzyme-linked immunosorbent assay. Normal leptin values were 2.6–11.1 ng/mL for women, and 2.0–5.6 ng/mL for men. The content of adipose tissue in the body was assessed by dual-energy X-ray absorptiometry.

RESULTS. Elevated serum leptin concentration was found in 58.2% of patients (decreased in 16.4%, normal in 25.4%). Increased leptin concentration was found in 67.1% of women and in 40.5% of men (p = 0.007). In patients with CAD, mean concentration of leptin reached 16.7 ng/mL; in patients without CAD, 15.3 ng/mL (p = 0.6). In patients with chronic heart failure, the probability of detecting low leptin levels increased by 3.2 times, compared with patients without heart failure (OR = 3.2; 95% CI = 1.1–9.9; p = 0.03). In patients with obesity, the mean leptin concentration was 28.5 ng/mL, while in patients without obesity it comprised 12.2 ng/mL (p = 0.00002). Significant correlation was found between the leptin concentration and body mass index (p < 0.000001). Significant positive correlation was registered between the serum leptin level and the adipose tissue content (p = 0.000001). The leptin concentration positively correlated with the concentration of total cholesterol (p = 0.02) and triglycerides (p = 0.003) in the blood serum. Patients with diabetes mellitus had higher leptin values (26.3 ng/mL vs 13.5 ng/mL in the group of patients without diabetes; p = 0.0003); a significant direct correlation was found between the concentration of leptin and glucose in the blood serum (p = 0.0003). In patients with low leptin concentration, lower bone mineral density was registered (p = 0.0003).

CONCLUSIONS: The study results suggest frequent leptin pathology in elderly and long-living patients, both with and without coronary artery disease. Higher leptin levels are associated with various metabolic disorders (obesity, dyslipidemia, and diabetes mellitus). Lower leptin levels are typical for patients with chronic heart failure.