Time dependent effect of melatonin administration on lipid peroxidation, superoxide dismutase activity and melatonin concentration in the elderly patients with essential arterial hypertension]

Oxidative stress and melatonin (the pineal hormone) are involved in the pathogenesis of aging and aging-related diseases, including essential arterial hypertension. The aim of study was determination of time dependent effect of melatonin administration on malondialdehyde (MDA) concentration, Cu, Zn-superoxide dismutase (SOD-1) activity and melatonin concentration in the elderly patients with essential arterial hypertension. The study was carried out on 11 patients with essential arterial hypertension (NT group, average 76.7 +/- 10 years), who were treated with thiazide diuretic. The reference group (K) was constituted 13 people without the chronic diseases (average 76.9 +/- 8 years). In the groups NT and K melatonin (Melatonin 5mg, LEKAM) one hour before sleep was administrated. MDA concentration and SOD-1 activity was performed before beginning of experiment and after 15 and after 30 days of the melatonin administration. Melatonin concentration was determined before beginning of experiment and after 30 days of the melatonin administration. Venous blood was taken from the cubital vein at 08.00 am. Melatonin concentration was determined in serum, and MDA content and SOD-1 acitivity were determined in erythrocytes. In NT group in comparison to K group non-significant higher MDA concentration (0.293 +/- 0.03 and 0.286 +/- 0.03 micromol/g Hb, respectively), lower SOD-1 activity (2591 +/- 304.1 and 2630 +/- 301 U/g Hb, respectively) and lower melatonin concentration (7.65 +/- 4.6 and 8.36 +/- 4.7 pg/ml, respectively) were observed. After 15 days of melatonin administration lower MDA concentration and higher SOD-1 activity: in NT group (0.250 +/- 0.03, p < 0.01 and 2757 +/- 299, NS, respectively) and in K group (0.264 +/- 0.03, NS and 3065 +/- 529, p < 0.02, respectively) were measured. After 30 days of supplementation MDA concentration further decreased in NT group (0.247 +/- 0.03, NS) and in K group (0.240 +/- 0.03, p < 0.002). However, after 30 days of melatonin administration in comparison to the results of 15 days the statistically non-significant differences of SOD-1 activity, either in NT group (2680 +/- 332 U/g Hb) and in K group (3012 +/- 417 U/g Hb) were observed. After 30 days of supplementation melatonin concentration increased in NT group (19.57 +/- 11.7 pg/ml, p < 0.01) and in K group (19.33 +/- 17.8 pg/ml, p < 0.05). The results may indicate on the intensification of oxidative stress in elderly patients with essential arterial hypertension and on the beneficial antioxidant effect of melatonin, already after 15 days of supplementation. This results may have indicates on the therapeutic implications.