Capsaicin-induced cardioprotection. Is hypothermia or the salvage kinase pathway involved?

Purpose: Topical capsaicin application was shown to reduce infarct size in experimental animal models. We hypothesized that cardioprotective properties of topical capsaicin application could be related to its hypothermic effect.

Methods: In the first arm of the study, anesthetized rats received capsaicin cream (Caps group) or vehicle (Control group, Ctrl) applied either 15 or 30 min prior to a 30-min coronary artery occlusion followed by 2-h reperfusion.

Role of protein kinase C in ischemic "conditioning": from first evidence to current perspectives.

Since the discovery of ischemic preconditioning (IPC) 26 years ago, numerous studies attempted to determine the mechanism of this powerful form of cardioprotection. One of the first proposed pathways of IPC suggested that the preconditioning stimulus activated phospholipase C via G-protein, and diacylglycerol released from phospholipid moieties activated protein kinase C (PKC) by translocating it from the cytosol to the sarcolemmal membranes. The major protective isoform of PKC was found to be the PKC-∈.

Remote ischemic preconditioning for coronary artery bypass graft operations.

Ischemia-reperfusion injury occurs during coronary artery bypass graft operations. Strategies are needed to lower the extent of damage. Attempts to find these strategies have been occurring for more than 40 years, with remote ischemic preconditioning being one method.

The effect of acute versus delayed remote ischemic preconditioning on reperfusion induced ventricular arrhythmias.

Introduction: The effect of remote ischemic preconditioning (RIPC) on arrhythmias in in vivo models is unknown. Our purpose was to determine effects of both acute and delayed RIPC on arrhythmias.

Methods And Results: In the acute protocol anesthetized open chest rats were exposed to 5 minutes of proximal left coronary artery occlusion (CAO) and 10 minutes of reperfusion.

Ranolazine as a cardioplegia additive improves recovery of diastolic function in isolated rat hearts.

Background: Ranolazine (Ran), an antianginal agent, inhibits late Na(+) current. The purpose of this study was to determine whether there was an added benefit of adding Ran to cardioplegia (CP) in a model of global ischemia/reperfusion.

Methods And Results: Isolated rat hearts were Langendorff-perfused and exposed to 40-minute normothermic, cardioplegic global ischemia and 30 minutes of reperfusion.

Particulate air pollution and coronary heart disease.

Purpose Of Review: Air pollution poses a significant health risk. The article focuses on the adverse effects of air pollution on the cardiovascular system.

Recent Findings: Short-term and long-term studies clearly indicate that relatively modest exposures to particulate matter in the ambient air are associated with increased morbidity and mortality due to coronary heart disease.

Ranolazine as an adjunct to cardioplegia: a potential new therapeutic application.

The purpose of this study was to examine the therapeutic potential of ranolazine, a novel antianginal drug, as an adjunctive therapy to hyperkalemic cardioplegia. Rat hearts were Langendorff-perfused and exposed to 40 minutes of ischemia and 30 minutes of reperfusion without (control) or with cardioplegia or cardioplegia with 50 micromol/L ranolazine. During ischemia, cardioplegia prolonged time to contracture, defined as the time to reach an intraventricular pressure of 20 mm Hg, from 12 +/- 1 minute (control) to 25 +/- 2 minutes (P < .

Ischemic preconditioning maintains cardioprotection in aging normotensive and spontaneously hypertensive rats.

We determined whether ischemic preconditioning could reduce infarct size and improve cardiac function in both aging normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). The left anterior descending coronary artery was occluded for 1h followed by 3 h reperfusion in aging ( approximately 16 months old) SHR rats and age-matched WKY rats. Hearts were either preconditioned or not (control group) prior to 1h of coronary artery occlusion.

Air pollution and cardiovascular injury epidemiology, toxicology, and mechanisms.

Recent epidemiologic studies show that increased levels of air pollutants are positively associated with cardiovascular morbidity and mortality. Inhalation of air pollutants affects heart rate, heart rate variability, blood pressure, vascular tone, blood coagulability, and the progression of atherosclerosis. Several categories within the general population (i.

Direct and acute cardiotoxic effects of ultrafine air pollutants in spontaneously hypertensive rats and Wistar--Kyoto rats.

It is hypothesized that preexisting cardiovascular disease could affect the susceptibility to direct and acute cardiotoxic effects of ultrafine air pollutants. Ultrafine particles (UFP) isolated from 12.5 mg of diesel particulate matter (National Institute of Standards and Technology) were infused into isolated Langendorffperfused hearts obtained from spontaneously hypertensive rats (SHR) and normotensive control Wistar- Kyoto rats (WKY).

Direct and acute cardiotoxicity of ultrafine particles in young adult and old rat hearts.

Background: Air pollution is associated with significant increases in cardiac morbidity and mortality in the general population. The elderly cohort within the general population is considered at high risk for cardiac diseases. However the degree to which air pollutants affect cardiac responses in old hearts vs.

In vivo and in vitro models to test the hypothesis of particle-induced effects on cardiac function and arrhythmias.

Exposure to ultrafine particles (UFPs) by inhalation increases the number and severity of cardiac events. The specific mechanism(s) of action are unknown. This study was designed to examine whether UFPs could exert a direct effect on the cardiovascular system without dependence upon lung-mediated responses.

Molecular aspects of ischemic heart disease: ischemia/reperfusion-induced genetic changes and potential applications of gene and RNA interference therapy.

Molecular biologic techniques have a variety of applications in the study of ischemic heart disease, including roles in elucidating cardiac genetic changes resulting from ischemia as well as in developing therapeutic interventions to treat ischemic heart disease. This review describes recent studies documenting genetic changes associated with myocardial ischemia and infarction as well as those investigating the safety and effectiveness of gene therapy for stimulating angiogenesis, protecting the heart against reperfusion injury, and treating heart failure. Also discussed are future research directions, including the potential use of RNA interference and combined stem cell therapy and gene therapy for the treatment of cardiovascular disease.

Mildronate, a novel fatty acid oxidation inhibitor and antianginal agent, reduces myocardial infarct size without affecting hemodynamics.

Mildronate is a fatty acid oxidation inhibitor approved as an antianginal drug in parts of Europe. We carried out the first study to determine whether a 10-day course of mildronate could reduce myocardial infarct size (IS) during acute myocardial ischemia. Sprague Dawley rats received 200 mg/kg/d of mildronate (treated group, n = 16) or sterile water (control group, n = 14) subcutaneously for 10 days before ischemia-reperfusion.

Washout of transplanted cells from the heart: a potential new hurdle for cell transplantation therapy.

Objective: The number of viable transplanted cells in the heart is sharply decreased shortly after cell injection. The exact mechanics of cell loss are unclear. We hypothesized that immature cardiac cells transplanted directly into rat heart could be washed out via the cardiac vasculature, and carried to other organs.

Metabolic mechanism by which mild regional hypothermia preserves ischemic tissue.

Background: Our laboratory demonstrated that mild regional hypothermia reduced myocardial infarct size by an average of 65% in the rabbit model of regional ischemia. The exact mechanism for this benefit has not been explored. We hypothesized that a moderate reduction in regional myocardial temperature could preserve cardiac energy metabolism and thus protect the myocardium from sustained ischemic insult.

Age-related changes of cardiac gene expression following myocardial ischemia/reperfusion.

Young and old (4 and 25 months of age, respectively) Fisher 344/Brown Norway hybrid female rats were subjected to four 3 min episodes of ischemia separated by 5 min of reperfusion. Corresponding open-chest sham-operated groups received 32 min of no intervention. All rats were allowed to recover, and 24h later hearts were removed and frozen in liquid nitrogen.

Mechanisms of myocardial ischemic preconditioning are age related: PKC-epsilon does not play a requisite role in old rabbits.

Data obtained from adult cohorts have implicated activation/translocation of protein kinase C (PKC)-epsilon as an important cellular mediator of myocardial infarct size reduction with ischemic preconditioning (PC). Age-related alterations in cellular signaling may, however, confound the extrapolation of mechanistic insight derived from adults to the aging population, the specific subset in which cardioprotection is undoubtedly most relevant. Accordingly, our aim was to investigate the role of PKC-epsilon as a mediator of infarct size reduction with PC in old vs.

Brief episode of ischemia activates protective genetic program in rat heart: a gene chip study.

Objective: Brief episodes of ischemia of 20 min or less have the potential to protect the heart. Such episodes are associated primarily with reversible ischemic injury yet they induce changes in gene expression. The purpose of the study was to determine whether activation of protective genes takes place within 4 h following a brief episode of ischemia that would mimic angina pectoris.

Gene expression profiling--a new approach in the study of myocardial ischemia.

Current technologies make it possible to study thousands of genes simultaneously in the same biological sample - an approach termed gene expression profiling. Several techniques, including (i) differential display, (ii) serial analysis of gene expression (SAGE), (iii) subtractive hybridization and (iv) gene microarrays (Gene Chips), have been developed. Recently, gene profiling was applied in studying the mechanisms of ischemic injury and ischemic preconditioning.

Transplantation of neonatal cardiomyocytes after permanent coronary artery occlusion increases regional blood flow of infarcted myocardium.

Background: Cellular cardiomyoplasty is a promising approach for rebuilding scar tissue after acute myocardial infarction. However, the angiogenic potential of transplanted immature cardiomyocytes and their effect on regional myocardial blood flow (RMBF) after coronary artery occlusion remain to be evaluated.

Methods And Results: Intramyocardial injection of cultured neonatal cardiomyocytes (4 x 10(6) cells/50-70 microliter) into the scar 1 week after permanent coronary occlusion in rats resulted in improved RMBF in the infarct 4 weeks after transplantation (radioactive microspheres, 0.

Gene activity changes in ischemically preconditioned rabbit heart gene: discovery array study.

This study tested the hypothesis that classic ischemic preconditioning can cause changes in gene expression patterns in the rabbit heart, assessed by gene array technology. Open-chest rabbits were randomly assigned to sham-operated and ischemically preconditioned groups. The sham-operated group received 5 hours and 20 minutes of no intervention, while the ischemically preconditioned group was subjected to two episodes of preconditioning ischemia (5 minutes each) separated by 5 minutes of reperfusion, followed by an additional 5 hours and 5 minutes of reperfusion.