Editorial [Hot Topic:Metabolic Therapy: An Important Therapeutic Option for the Treatment of Cardiovascular Diseases (Executive Editors: G.M.C. Rosano and G. Barbaro)]

The concept of metabolic modulation has an important part in the treatment of cardiovascular disease. It is now clear that ischemic heart disease, heart failure and diabetic cardiomyopathy have in common a derangement of cardiac metabolism shifted towards a greater utilization of free fatty acids and a reduced efficiency of the Krebs cycle. Over the past decades, several dugs that have been shown to improve cardiac metabolism in patients with ischemic heart disease and more recently in those with heart failure. These drugs include carnitine palmitoyl transferase (CPT)- I and/or -II inhibitors, such as etomoxir and perhexiline, essential amino acids, and long-chain 3- ketoacyl coenzyme A thiolase (LC3-KAT) inhibitors, such as trimetazidine and ranolazine. Some of these drugs are believed to work by partially inhibiting the oxidation of fatty acids in ischemic myocytes, others by improving the efficiency of the Krebs cycle. Since the oxidation of glucose is more energy efficient than fatty acid oxidation it becomes clear that enhancement of glucose metabolism should be pursued when oxygen availability is limited in underperfused cardiac tissue and in failing cardiomyocytes. Most of the drugs modulating cardiac metabolism are approved for the treatment of angina pectoris in most of Europe, Asia and Australia but not in the United States. On the contrary, ranolazine that was thought to be a metabolic agent but that now is supposed to have a different, yet not clear, mechanism of action, is approved for use in the United States but not in Europe. In this issue of Current Pharmaceutical Design, the metabolic basis of myocardial ischemia and dysfunction and the rationale for metabolic therapy in ischemic heart disease and heart failure are carefully reviewed by international experts who have mostly contributed in this area of research and matured a sound clinical experience.Yoshimura et al. [1] discuss the metabolic changes that occur in patients with diabetes mellitus and some of the metabolic therapeutic options currently available. Karastergiou and Kaski [2] discuss in depth the medical management of the diabetic patient with ischemic heart disease and highlight the need of optimization of cardiac metabolism. Vitale et al. [3] analyse the effects of drugs (e.g., dichloroacetate, L-carnitine, propionyl L-carnitine, CPT-I and LC3-KAT inhibitors) that may optimize the cardiac metabolism in patients with diabetes mellitus. Rosano et al. [4] review the metabolic changes that occur during myocardial ischemia, with related therapeutic implications, whereas Chagas et al. [5] review the importance of modulation of cardiac metabolism in patients with ischemic heart disease and the use of pharmacological strategies to improve the cardiac metabolism by the activation of pyruvate dehydrogenase (e.g., dichloroacetate), reduction of cellular uptake of free fatty acids (e.g., glucose and insulin), inhibition of mitochondrial transport of free fatty acids by CPT-I inhibitors (e.g., perhexiline and etomoxir), and inhibition of beta-oxidation of free fatty acids by LC3-KAT inhibitors (e.g., trimetazidine and, possibly, ranolazine). Heart failure is often the late stage of chronic ischemic heart disease. Dalla Libera et al. [6] review the pathophysiological and molecular (e.g., cardiomyocyte apoptosis) phenomena responsible for contractile dysfunction in heart failure, whereas Fragasso et al.[7] examine the possible effect of modulation of cardiac metabolism in patients with heart failure by acting on different metabolic pathways (e.g., inhibition of free fatty acids oxidation, xantineoxidase inhibition, mitochondrial metabolic oxidation). Marazzi et al. [8] analyze the role of amino acids in the modulation of cardiac metabolism during myocardial ischemia and heart failure by multiple actions they can provide (e.g., improvement of the oxidative stress by counteracting the action of radical oxygen species; positive action on endothelial function; increase of protein synthetic efficiency of myocardial cells by regulating gene expression; modulation of hormonal activity). Finally, Fazio et al. [9] critically revise the literature data on the possible role of statins (mainly, their pleiotropic effects) in preventing the progression of congestive heart failure in patients with metabolic syndrome. We wish to thank all the authors for their important contributions. It is our hope that this issue may represent a useful guide for a reasoned approach to metabolic therapy in patients with ischemic heart disease and/or heart failure.