Background This study was undertaken to compare plasma concentrations of leptin and some parameters of carbohydrate and lipid metabolism in patients with essential hypertension with or without the metabolic syndrome.
Material and methods The study group included 102 patients with stage I or II essential hypertension according to the Polish Arterial Hypertension Society [14]. Two groups were formed. One group (ZM) comprised 50 obese patients (26 females and 24 males, BMI 32.1 ± 2.1 kg/m²) aged 34.1 ± 5.3 years, with symptoms of the metabolic syndrome. The other group (HT) included 52 patients (26 females and 26 males), with normal body weight (BMI 23.1 ± 1.2 kg/m²), aged 33.0 ± 6.2, without symptoms of the metabolic syndrome. Blood samples were obtained for biochemical and hormonal assays. Concentrations of glucose and lipids were measured with enzyme-based tests. Insulin concentrations were measured with IRMA. Insulin resistance (IR) was determined with HOMA. Leptin (LEP), plasma renin activity (ARO), and plasma aldosterone (ALDO) levels were measured with RIA kits.
Results Both groups of patients were matched for age and values of blood pressure. Patients with the metabolic syndrome demonstrated higher BMI, waist circumference, and WHR values. Concurrently, they presented with significantly higher concentrations of total cholesterol, LDL, triglycerides, and TG/HDL as well as lower concentrations of HDL. Concentrations of insulin, leptin, ARO, and ALDO and insulin resistance values were elevated in ZM patients. In this group, leptin correlated positively with BMI, 24 h urinary sodium excretion (UNa), HDL, insulin, IR, ARO, and ALDO, and negatively with TG/HDL. Furthermore, blood pressure correlated positively with BMI, WHR, insulin, leptin, ARO, and ALDO. Pulse rate correlated positively with BMI, WHR, insulin, IR, leptin, ARO, and ALDO in this group. Multiple regression in ZM patients revealed that systolic blood pressure correlated with BMI, IR, and leptin, while diastolic blood pressure correlated with pulse rate and WHR. Such correlations were not found in patients without the metabolic syndrome.
Conclusions Correlations between leptin and blood pressure, pulse rate, and biochemical parameters indicate that leptin participates directly and indirectly in the mechanism responsible for metabolic disorders in the metabolic syndrome.