The Effect of High Dose Melatonin on Cardiac Ischemia-reperfusion Injury

PURPOSE: Melatonin, the most potent scavenger of toxic free radicals, has been found to be effective in protecting against pathological states due to the release of reactive oxygen species. This study was performed to establish the effect of high dose melatonin on protection against ischemia- reperfusion (I/R) injury in rat hearts. MATERIALS AND METHODS: Forty male Sprague-Dawley rats were used in this study. They were separated into four groups of ten rats each. A left coronary artery occlusion was induced in the rats by ligating the artery for 20 minutes and then releasing the ligation (reperfusion) afterwards. The control group was Group A. Group B was subjected to myocardial ischemia-reperfusion without any treatment, while Group C underwent myocardial ischemia-reperfusion with a melatonin treatment before the ischemia. Group D was subjected to myocardial ischemia-reperfusion with a melatonin treatment before the reperfusion. After 20 minutes of reperfusion, blood samples were obtained from each group for biochemical studies, and the animals were sacrificed for histological and, immunohistochemical examinations of the myocardial tissue. RESULTS: We found that the cardiac troponin T(cTn-T) levels were significantly increased in Group B when all groups were compared. In the Group C rats treated with melatonin, the cTn-T values were significantly lower than those in Groups B and D. In addition, malondialdehyde (MDA) and antioxidant enzymes including, superoxide dismutase (SOD) and myeloperoxidase (MPO) were lower than those in Group B in the melatonin treated groups. The differences were statistically significant (p < 0.05). Histopathologic and immunohistopathologic studies also supported the effectiveness of melatonin. CONCLUSION: Our study suggests that high dose melatonin, appears to offer protection against cardiac ischemia-reperfusion injuries in rats by scavenging the free radicals and could have a potential clinical use in the management of myocardial ischemia.

association of plasma homocysteine levels with serum leptin and apolipoprotein B levels in childhood obesity

An elevated plasma total homocysteine [tHcy] level has recently been established as an independent risk factor for thrombosis and vascular disease. However, the relationship between hyperhomocysteinemia and cardiovascular disease and obesity remains controversial. The aim of the study was to investigate a possible relationship between plasma tHcy levels and measures of childhood obesity. Forty children and adolescents with exogenous obesity and 20 non-obese subjects in an age-and sex-matched control group were investigated. Fasting samples were collected for plasma tHcy, serum insulin, leptin, vitamin B12, folate, creatinine and lipid parameters. Anthropometric characteristics and body compositions were assessed in both groups. The obese patients had significantly higher tHcy levels than the non-obese controls [14.3 +/- 11.8 micro mol/L vs 8.7 +/- 5.9 micro mol/L; P=0.017]. In both groups, plasma tHcy was positively related to serum leptin, but serum apolipoprotein B [apo B] levels were positively related to plasma tHcy levels only in obese patients. Our study demonstrates for the first time that leptin and apo B are main correlates of tHcy in obese children and adolescents and suggests that hyperleptinemia and increased apo B may contribute to impairment of tHcy metabolism in childhood obesity

Plasma homocysteine and retinal artery occlusive disease: a case-control study

Previous studies have documented that elevated plasma homocysteine is a risk factor for cardiovascular, cerebrovascular and peripheral vascular disease. In a case-control study, we sought to determine whether elevated homocysteine [HCY] is a risk factor for retinal artery occlusive disease. Patients and Methods. Study subjects consisted of 20 patients [12 male, 8 female] [mean age, 55.8; range 42-70 years] with clinical and objective evidence of retinal vascular occlusive disease and 20 age-matched control subjects [9 males, 11 females] [mean age, 55.3 years; range 50-68 years]. Hyperhomocysteinemia was defined as a plasma HCY level >15 micro mol/L by HPLC. We also measured concentrations of triglycerides, and total cholesterol, LDL cholesterol, and HDL cholesterol. The mean plasma HCY level in the patient group was 21.23 +/- 9.53 micro mol/L [range, 8.00-43.99 micro mol/L] compared with 12.59 +/- 4.97 micro mol/L [range, 6.38 to 22.88 micro mol/L] in the control group [P<0.008]. There was no correlation between HCY and serum triglycerides or cholesterol levels within each group. We conclude that high plasma HCY level may be a risk factor for retinal artery occlusive disease