Does Leptin Play a Role in the Pathogenesis of Essential Hypertension?

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Abstract
Background: Leptin is produced and released by adipocytes in proportion to fat stores. Leptin as an anorectic hormone plays an important role in the regulation of food intake, energy expenditure, and insulin secretion. In contrast, neuropeptide Y, insulin, cortisol, and growth hormone are presumed to be appetite modulators. Leptin and neuropeptide Y are both involved in the activation of sympathetic tone. Increased body fat stores in obese patients are involved in the pathogenesis of some metabolic disorders (e.g., hyperinsulinaemia, glucose intolerance) and arterial hypertension. Methods and Results: Based on this pathophysiological background, we tried to assess the relationship between plasma leptin and blood pressure in 41 patients with essential hypertension (EHP; 20 females, 21 males, mean age 38.7±1.9 years, mean body mass index – BMI – 25.8±0.5 kg/m2) and in an appropriately sex– and BMI–matched control group of 27 normotensive healthy subjects (NHS; 11 females, 16 males, mean age 39.7±2.5 years, mean BMI 24.8±0.6 kg/m2). The plasma leptin concentration did not differ significantly between EHP and NHS (13.0±1.9 vs. 8.1±1.0 ng/ml, respectively). In both groups a significant positive correlation was found between BMI and plasma leptin concentration (p<0.0001). A significant positive correlation (p<0.02) was found between leptinaemia and mean (MAP), systolic and diastolic blood pressures, if data were analyzed for all examined subjects or separately only for women. Such a correlation could not be confirmed for male NHS and EHP subjects. The plasma neuropeptide Y concentration was higher in EHP than in NHS (77.1±23.0 vs. 63.6±9.8pg/ml, p = 0.05). In contrast to neuropeptide Y plasma insulin, cortisol, and growth hormone concentrations were similar in EHP and in NHS. Conclusion: Both EHP and NHS are characterized by a positive correlation between BMI and leptinaemia. Leptin may be indirectly involved in blood pressure regulation, especially in women of both NHS and EHP.