Melatonin treatment improves blood pressure, lipid profile, and parameters of oxidative stress in patients with metabolic syndrome

Experimental studies have proven that melatonin has many beneficial pleiotropic actions. The aim of this study was to assess melatonin efficacy in patients with metabolic syndrome (MS). The study included 33 healthy volunteers (who were not treated with melatonin) and 30 patients with MS, who did not respond to 3-month lifestyle modification. Patients with MS were treated with melatonin (5 mg/day, 2 hr before bedtime) for 2 months. The following parameters were studied: systolic and diastolic blood pressure (SBP, DBP), levels of glucose, serum lipids, C-reactive protein, fibrinogen, activities of antioxidative enzymes: catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), thiobarbituric acid reactive substrates (TBARS). After 2-month therapy in comparison with baseline, the following significant changes were measured: systolic blood pressure (132.8 +/- 9.8 versus 120.5 +/- 11.0 mmHg, P < 0.001), DBP (81.7 +/- 8.8 versus 75 +/- 7.4 mmHg, P < 0.01), low-density lipoprotein cholesterol (LDL-C) (149.7 +/- 26.4 versus 139.9 +/- 30.2 mg/dL, P < 0.05), TBARS (0.5 +/- 0.2 versus 0.4 +/- 0.1 mu m/gHb, P < 0.01), and CAT (245.9 +/- 46.9 versus 276.8 +/- 39.4 U/gHb). Melatonin administered for 2 months significantly improved antioxidative defense (increase in CAT activity, decrease in TBARS level) and lipid profile (decrease in LDL-C), and lowered blood pressure. We conclude that melatonin therapy may be of benefit for patients with MS, particularly with arterial hypertension. Further studies with higher doses of melatonin or prolonged supplementation are awaited.