Levosimendan: Beyond its simple inotropic effect in heart failure

Classic inotropic agents provide short-term haemodynamic improvement in patients with heart failure, but their use has been associated with poor prognosis. A new category of inotropic agents, the Ca2+ sensitizers, may provide an alternative longer lasting solution. Levosimendan is a relatively new Ca2+ sensitizer which offers haemodynamic and symptomatic improvement by combining a positive inotropic action via Ca2+ sensitization and a vasodilatory effect via adenosine triphosphate(ATP)-sensitive K+ (K-ATP), Ca2+-activated K+ (KCa2+) and voltage-dependent K+ (K-v) channels activation. Levosimendan also seems to induce a prolonged haemodynamic improvement in patients with heart failure as a result of the long half-life of its active metabolite, OR-1896. Furthermore, there is also evidence that levosimendan may have additional antiinflammatory and antiapoptotic properties, affecting important pathways in the pathophysiology of heart failure. Despite the initial reports for a clear benefit of levosimendan on short- and long-term mortality in patients with severe heart failure, the results from the recent clinical trials are rather disappointing, and it is still unclear whether it is superior to dobutamine in affecting survival of patients with severe heart failure. In conclusion, levosimendan is a promising agent for the treatment of decompensated heart failure. As further to its positive inotropic effect, it affects multiple pathways with key roles in the pathophysiology of heart failure. The results of the ongoing trials examining the effect of levosimendan on mortality in patients with heart failure will hopefully resolve the controversy as to whether levosimendan is superior to classic inotropic agents for the treatment of severe heart failure. (c) 2007 Elsevier Inc. All rights reserved

Homocysteine and coronary atherosclerosis: from folate fortification to the recent clinical trials

Plasma total homocysteine (Hcy) has been associated with cardiovascular risk in multiple large-scale epidemiological studies, and it has been considered as an independent risk factor for atherosclerosis. Homocysteine lowering, achieved after the introduction of the folate food fortification programme in North America, was accompanied by an accelerated decline of cardiovascular risk and especially of stroke. Although the initial clinical trials suggested that homocysteine-lowering treatment with folates and B vitamins induces coronary plaque regression, this finding was not confirmed by more recent clinical studies. Under the light of the findings from the recent large randomized clinical trials that failed to document a benefit of Hcy lowering on clinical outcome of patients with atherosclerosis, the role of Hcy as a risk factor and the efficacy of Hcy lowering against atherosclerosis have been questioned. Therefore, better understanding of the mechanisms relating Hcy and Hcy-lowering treatment with vascular function and atherogenesis is crucial, to help us understand why clinical trials failed to show a benefit from Hcy-lowering treatment. Are these therapeutic strategies ineffective because they fail to reduce intracellular Hcy levels and vascular redox state or should Hcy stop being considered as an independent risk factor for atherosclerosis from now on? In this review article, we provide a global approach of the molecular mechanisms relating Hcy with cardiovascular risk and introduce possible mechanistic explanations regarding the inability of clinical trials to detect any clinical benefit from Hcy-lowering treatment in secondary prevention. Finally, we provide clinical recommendations regarding the therapeutic strategies targeting homocysteine in the general population

Genetic polymorphisms of platelet glycoprotein Ia and the risk for premature myocardial infarction - Effects on the release of sCD40L during the acute phase of premature myocardial infarction

OBJECTIVES The aim of this research was to evaluate the effect of genetic polymorphisms C807T and G1648A of platelet glycoprotein la (GPIa), on the risk for myocardial infarction (MI) and on the release of soluble CD40 ligand (sCD40L) during the acute phase of MI and one year after the event. BACKGROUND C807T and G1648A polymorphisms affect the density of GPIa on platelet surface, but their effect on the risk for MI and the release of sCD40L is unknown. METHODS The study population consisted of 219 patients with premature MI and 389 controls. One year after the event, 67 patients and 232 controls were recalled for the follow-up study. RESULTS The risk for MI in 807TT was 2.296 (95% confidence interval [CI]: 1.187 to 4.440) p < 0.05 versus CC + CT, 2.269 (95% CI: 1.085 to 4.745) p < 0.05 versus CC, and 2.135 (95% CI: 1.080 to 4.219) p < 0.05 versus CT. During the acute phase of MI, sCD40L was higher in 807CT + TT compared with 807CC (p < 0.01), an effect persisting after one year (p < 0.01). The carriage of 807T allele was an independent predictor for sCD40L during the acute phase of MI (beta = 9.442 [standard error (SE): 2.526], p = 0.001) and in the same patients one year later (beta =8.282 [SE: 2.044], p = 0.001). In healthy individuals, 807T allele was associated with higher sCD40L levels compared with 807CC (p < 0.05), only among those with von Willebrand factor greater than or equal to median. CONCLUSIONS Genetic polymorphism C807T increases the risk for premature MI. 807T allele is an independent predictor for sCD40L levels during the acute phase of premature MI as well as one year after the event, while it is associated with elevated sCD40L levels in healthy subjects, only in the presence of high von Willebrand levels. (J Am Coll Cardiol 2006;47:1959-66) (c) 2006 by the American College of Cardiology Foundation

Young women partition fatty acids towards ketone body production rather than VLDL-TAG synthesis, compared with young men

Before the menopause, women are relatively protected against CVD compared with men. The reasons for this sex difference are not completely understood, but hepatic fatty acid metabolism may play a role. The present study aimed to investigate the utilisation of plasma NEFA by the liver and to determine whether they are partitioned differently into ketone bodies and VLDL-TAG in healthy, lean young men and women. Volunteers were studied during a prolonged overnight fast (12-19 h) using an intravenous infusion of [U-C-13] palmitate. After 12 h fasting, the women had a more advantageous metabolic profile with lower plasma glucose (P < 0.05) and TAG (P < 0.05) but higher plasma NEFA (P < 0.05) concentrations. Plasma 3-hydroxybutyrate (3-OHB) concentrations rose more in women than in men, and the transfer of C-13 from [U-(13) C]palmitate to plasma [C-13]3-OHB reached a plateau 6-7 h after the start of the infusion in women but was still increasing at 6 h in men. This implies a slower 3-OHB production rate and/or dilution by other precursor pools in men. In women, the high isotopic enrichment of plasma 3-OHB suggested that systemic plasma fatty acids were the major source of 3-OHB production. However, in men, this was not observed during the course of the study(P < 0.01). There were no sex differences for the incorporation of C-13 into VLDL1-or VLDL2-TAG. The ability of young women to partition fatty acids towards ketone body production rather than VLDL-TAG may contribute to their more advantageous metabolic profile compared with young men

LRP5 regulates human body fat distribution by modulating adipose progenitor biology in a dose- and depot-specific fashion

Summary Common variants in WNT pathway genes have been associated with bone mass and fat distribution, the latter predicting diabetes and cardiovascular disease risk. Rare mutations in the WNT co-receptors LRP5 and LRP6 are similarly associated with bone and cardiometabolic disorders. We investigated the role of LRP5 in human adipose tissue. Subjects with gain-of-function LRP5 mutations and high bone mass had enhanced lower-body fat accumulation. Reciprocally, a low bone mineral density-associated common LRP5 allele correlated with increased abdominal adiposity. Ex vivo LRP5 expression was higher in abdominal versus gluteal adipocyte progenitors. Equivalent knockdown of LRP5 in both progenitor types dose-dependently impaired β-catenin signaling and led to distinct biological outcomes: diminished gluteal and enhanced abdominal adipogenesis. These data highlight how depot differences in WNT/β-catenin pathway activity modulate human fat distribution via effects on adipocyte progenitor biology. They also identify LRP5 as a potential pharmacologic target for the treatment of cardiometabolic disorders. © 2015 The Authors

Novel therapies targeting vascular endothelium

Endothelial dysfunction has been identified as a major mechanism involved in all the stages of atherogenesis. Evaluation of endothelial function seems to have a predictive role in humans, and therapeutic interventions improving nitric oxide bioavailability in the vasculature may improve the long-term outcome in healthy individuals, high-risk subjects, or patients with advanced atherosclerosis. Several therapeutic strategies are now available, targeting both the synthesis and oxidative inactivation of nitric oxide (NO) in human vasculature. Statins seem to be currently the most powerful category of these agents, improving endothelial function and decreasing cardiovascular risk after long-term administration. Other cardiovascular agents improving endothelial function in humans are angiotensin-converting enzyme inhibitors/angiotensin receptors blockers, which increase NO bioavailability by modifying the rennin-angiotensin-aldosterone system. Newer therapeutic approaches targeting endothelial dysfunction in specific disease states include insulin sensitizers, L-arginine (the substrate for endothelial NO synthase [eNOS]) as well as substances that target eNOS “coupling,” such as folates or tetrahydrobiopterin. Although there are a variety of strategies to improve NO bioavailability in human endothelium, it is still unclear whether they have any direct benefit at a clinical level

Moisture Status of the Skin of the Feet Assessed by the Visual Test Neuropad Correlates With Foot Ulceration in Diabetes

OBJECTIVE - To examine the association between the moisture status of the skin of the feet with foot ulceration in subjects with diabetes. RESEARCH DESIGN AND METHODS - A total of 379 subjects with diabetes were examined. Assessment of peripheral neuropathy was based on neuropathy symptom score, neuropathy disability score, vibration perception threshold, and the 10-g monofilament perception. The moisture status of the skin of the feet was assessed using the visual test Neuropad. RESULTS - Patients with foot ulceration had more severe peripheral neuropathy and more often an abnormal Neuropad response. Multivariate logistic regression analysis demonstrated that the odds of foot ulceration increased with measures of neuropathy but increased also with an abnormal Neuropad response. CONCLUSIONS - An abnormal Neuropad response correlates with foot ulceration in subjects with diabetes. This finding, if confirmed prospectively, suggests that the Neuropad test may be included in the screening tests for the prediction of foot ulceration