E. Du Toit

MELATONIN AND THE METABOLIC SYNDROME: A TOOL FOR EFFECTIVE THERAPY IN OBESITY-ASSOCIATED ABNORMALITIES?

The metabolic syndrome (MetS) is a cluster of metabolic abnormalities associated with increased risk for cardiovascular diseases. Apart from its powerful antioxidant properties, the pineal gland hormone melatonin has recently attracted the interest of various investigators as a multifunctional molecule. Melatonin has been shown to have beneficial effects in cardiovascular disorders including ischaemic heart disease and hypertension. However, its role in cardiovascular risk factors including obesity and other related metabolic abnormalities is not yet established, particularly in humans. New emerging data show that melatonin may play an important role in body weight regulation and energy metabolism. This review will address the role of melatonin in the MetS focusing on its effects in obesity, insulin resistance and leptin resistance. The overall findings suggest that melatonin should be exploited as a therapeutic tool to prevent or reverse the harmful effects of obesity and its related metabolic disorders.

Myocardial structure, function and ischaemic tolerance in a rodent model of obesity with insulin resistance

•  What is the central question of this study? Does obesity with insulin resistance decrease left ventricular pump function and/or myocardial tolerance to ischaemia in a rodent model of metabolic syndrome, and what mechanisms are involved in these changes? •  What is the main finding and its importance? These data suggest that although left ventricular pump function may be maintained with obesity and insulin resistance, the hearts from these animals are more prone to ischaemia–reperfusion injury, which is in part due to changes in the functionality of the myocardial reperfusion injury salvage kinase (RISK) pathway. Interventions/therapies aimed at normalizing RISK pathway function have the potential to normalize myocardial tolerance to ischaemia–reperfusion in patients with the metabolic syndrome.

The effect of creatine supplementation on myocardial function, mitochondrial respiration and susceptibility to ischaemia/reperfusion injury in sedentary and exercised rats.

To investigate the effects of dietary creatine supplementation alone and in combination with exercise on basal cardiac function, susceptibility to ischaemia/reperfusion injury and mitochondrial oxidative function. There has been an increase in the use of creatine supplementation among sports enthusiasts, and by clinicians as a therapeutic agent in muscular and neurological diseases. The effects of creatine have been studied extensively in skeletal muscle, but not in the myocardium.

Chronically elevated bilirubin protects from cardiac reperfusion injury in the male Gunn rat

Bilirubin is associated with reduced risk of cardiovascular disease, as evidenced in conditions of mild hyperbilirubinaemia (Gilberts Syndrome). Little is known regarding myocardial stress resistance in hyperbilirubinaemic conditions or whether life‐long exposure modifies cardiac function, which might contribute to protection from cardiovascular disease.