Trimetazidine demonstrated cardioprotective effects through mitochondrial pathway in a model of acute coronary ischemia.

Myocardial ischemia affects mitochondrial function leading to ionic imbalance and susceptibility to ventricular fibrillation. Trimetazidine (TMZ), a metabolic agent, is clinically used as an anti-anginal therapy. This study was conducted to compare the effect of TMZ 20 mg immediate release (IR) and TMZ 35 mg modified release (MR), two bioequivalent marketed formulations of TMZ, on cardioprotection during acute ischemia in pigs. A 4-day oral treatment with TMZ 20 mg IR (800 mg, tid) or TMZ 35 mg MR (1,400 mg, bid) had no effect on ventricular fibrillation threshold (VFT) prior to ischemia but significantly prevented the decrease in VFT observed in placebo-treated groups after a 1-min left anterior descending coronary artery occlusion. This effect occurred without modifying cardiac hemodynamic and conduction parameters. In both TMZ-treated groups, a significant reduction of the ischemic area as well as a protection of cardiomyocytes were observed. Cardiac enzymatic activity (phosphorylase, succinate dehydrogenase, ATPase) was increased in TMZ-treated groups. Both formulations preserved mitochondrial structure and improved mitochondrial function as demonstrated by a twofold increase of oxidative phosphorylation, by a reduction of reactive oxygen species (ROS) production (>30 %) and by a trend to increase the mitochondrial calcium retention capacity. In this model of ischemia, both TMZ formulations, leading to equivalent TMZ plasma exposures, demonstrated similar cardioprotective effects. This protection could be attributed to a preservation of mitochondrial structure and function, which plays a central role in ATP and ROS production and consequently could be considered as a target of cardioprotection.

Cardiac lesions induced by 5-fluorouracil in the rabbit.

Cardiotoxicity is a rare, but well-recognized complication of treatments with the anti-cancer drug 5-fluorouracil (5FU). The underlying mechanism, however, is not fully elucidated. A spasm of the coronary arteries is often considered to be the leading cause of myocardial ischemia and decreased contractility associated with 5FU. As spasm cannot account for all reported adverse cardiac effects, the present study was undertaken to search for alternative mechanisms. Groups of six rabbits were given either a single intravenous dose of 50 mg/kg 5FU or four intravenous doses of 15 mg/kg 5FU at 7-day intervals. A third group served as control. The heart was removed shortly after death or scheduled sacrifice of the animals, to perform macroscopic and microscopic examinations of the heart and to evidence apoptosis by the TUNEL method. Following a single dose of 50 mg/kg 5FU, all animals rapidly developed a massive hemorrhagic myocardial infarct with spasms of the proximal coronary arteries. Repeated infusions of 15 mg/kg 5FU induced left ventricular hypertrophy, foci of myocardial necrosis, thickening of intra-myocardial arterioles, and disseminated apoptosis in myocardial cells of the epicardium, as well as endothelial cells of the distal coronary arteries. These results indicate that a spasm of the coronary arteries is not the only mechanism of 5FU cardiotoxicity, and that apoptosis of myocardial and endothelial cells can result in inflammatory lesions mimicking toxic myocarditis.

[Adult Kawasaki disease]. / La maladie de Kawasaki de l'adulte.

PURPOSE: Review of the literature on adult Kawasaki disease. CURRENT KNOWLEDGE AND KEY POINTS: Kawasaki disease is an acute multisystemic vasculitis affecting predominantly young children. Several studies have suggested that Kawasaki disease is mediated by bacterial superantigens. The diagnosis is established on clinical criteria since no specific laboratory test yet exists for this disorder. The severity of Kawasaki disease relates to the possible occurrence of coronary aneurysms in 20% of childhood cases. Treatment with intravenous immunoglobulins before day 10 is recommended to prevent aneurysm formation. The occurrence of Kawasaki disease is unusual in adults and 52 cases only have been reported in adult patients. Seventy-one per cent of cases occur between 18 and 30 years. The incidence of specific clinical features is quite similar between adults and children. However meningitis and thrombocytosis are more common in children than in adults, while conversely both arthralgias and liver function abnormalities are more common among adults. Coronary aneurysms are less common in the adults with Kawasaki disease. Other diseases with similar clinical presentation such as drug hypersensitivity reaction and the toxic shock syndrome must be ruled out. Kawasaki disease is often diagnosed after the acute phase at the step of desquamation, when it is too late to expect any beneficial effect from immunoglobulins. FUTURE PROSPECTS AND PROJECTS: Diagnostic criteria of Kawasaki disease have not been validated in an adult population. Criteria of exclusion are necessary to eliminate toxic shock syndrome and drug hypersensitivity syndrome. An international retrospective study to collect data on epidemiologic, clinical, laboratory, and cardiovascular features of adult Kawasaki disease is necessary to validate specific diagnostic criteria and to improve the knowledge on this disease.