Heterogeneity of apoptosis and myolysis in coronary microembolization: a competition between programmed cell death and programmed cell survival

The possible alleviating effect of saffron on chlorpyrifos experimentally induced cardiotoxicity: Histological, immunohistochemical and biochemical study

INTRODUCTION

Pesticides are responsible for many occupational health hazards among farmers in developing countries. Chlorpyrifos (CPF) is one of the broad-spectrum organophosphorus (OP) insecticides used for agricultural, domestic and industrial purposes.

AIM OF THE WORK

The present study was designed to examine the effects of CPF on cardiac muscles and to evaluate the possible protective role of crocin using biochemical and histological methods with the intention to recognize the molecular tools of its probable cardioprotective effects.

MATERIALS AND METHODS

Thirty-six adult male albino rats were used in this study and were divided into 4 equal groups (9 rats each): negative control group, positive control group, CPF treated group and CPF & crocin treated group. The heart was removed for histological and immunohistochemical studies.

RESULTS

Stained sections of cardiac muscle fibers of group III with H&E revealed remarkable histological changes in the form of disorganization of the fibers with increase in the interstitial spaces between these fibers. Congested dilated blood capillaries could be observed with extravasation of the red blood cells leading to interstitial hemorrhage. Focal areas of mononuclear cellular infiltration could be seen in the interstitial tissue. A number of cardiac fibers achieved pale acidophilic vacuolated sarcoplasm while others achieved dark homogenous acidophilic sarcoplasm. Some nuclei were peripherally situated and pyknotic while others were centrally situated and encircled with halos. Apparently increased masses of collagen fibers among the cardiac muscle fibers and around the congested dilated blood vessels with the presence of focal parts of extensive collagen fiber deposition were noticed in Mallory-stained sections of group III. Strong positive immunoreactions in the endomysium and perimysium of the cardiac fibers, along with the walls of blood capillaries and in interstitial cells, could be detected in immunohistochemical staining sections of group III with vimentin antibody. Immunoreactivity to caspase 3 was higher in the sarcoplasm of the cardiac fibers of group III compared to that of control group. A highly significant decrease in the cardiac level of SOD and CAT; however, a highly significant increase in MDA level was noted between the control groups and CPF treated group. Additionally, there was a significant improvement of the chemical and histological representations of group IV, and these improvement pictures were toward the normal.

CONCLUSION

The study concludes that crocin can alleviate the toxic effect of chlorpyrifos caused by oxidative stress on cardiac muscle.

Myocardial and Serum Galectin-3 Expression Dynamics Marks Post-Myocardial Infarction Cardiac Remodelling

BACKGROUND

Acute myocardial infarction (MI) causes significant changes in cardiac morphology and function. Galectin-3 is a novel and potentially therapeutically important mediator of cardiac remodelling. Myocardial and serum galectin-3 expression dynamics in response to the early cardiovascular outcomes after acute MI are not fully elucidated.

METHODS

We first performed a comprehensive longitudinal microarray analyses in mice after acute MI. We then measured the serum levels of galectin-3 in a translational porcine model of coronary microembolism-induced post-ischaemic cardiac remodelling. We validated our pre-clinical studies in humans by measuring serum galectin-3 levels of 52 patients with acute ST-elevation MI (STEMI) and 11 healthy controls. We analysed galectin-3 data in relation to the development of major adverse cardiovascular outcomes (MACO).

RESULTS

Of the 9,753 genes profiled at infarcted and remote myocardium at eight different time points, dynamic myocardial overexpression of galectin-3 mRNA was detected. In a pig model of diffuse myocardial damage and cardiac remodelling, galectin-3 localised to the areas of tissue damage and myocardial fibrosis, with proportionate increase of their serum galectin-3 expression levels. In humans, increased serum galectin-3 level was associated with in-hospital MACO.

CONCLUSIONS

In this translational study, we demonstrated that galectin-3 is dynamically overexpressed in response to acute MI-induced cardiac remodelling. Elevated galectin-3 levels are associated with the development of in-hospital MACO.

Role of apoptosis in adverse ventricular remodeling

Apoptosis is a key feature in the progression of heart disease. Stage B heart failure is characterized by a structurally abnormal heart in which the remodeled myocardium is prone to apoptosis. Elimination of the proapoptotic stimuli or inhibition of the apoptotic cascade could presumably rescue the myocardium and halt the progression of adverse remodeling and heart failure. In this article, the authors review the role of apoptosis (or programmed cell death) in determining the evolution of symptomatic heart failure and particularly the adverse remodeling in the aftermath of acute myocardial infarction.

Pathophysiologic role of myocardial apoptosis in post-infarction left ventricular remodeling

Left ventricular (LV) remodeling and heart failure (HF) complicate acute myocardial infarction (AMI) even weeks to months after the initial insult. Apoptosis may represent an important pathophysiologic mechanism causing progressive myocardiocyte loss and LV dilatation even late after AMI. This review will discuss the role of apoptosis according to findings in animal experimental data and observational studies in humans in order to assess clinical relevance, determinants, and mechanisms of myocardial apoptosis and potential therapeutic implications. More complete definition of the impact of myocardiocyte loss on prognosis and of the mechanisms involved may lead to improved understanding of cardiac remodeling and possibly improved patients' care. Mitochondrial damage and bcl-2 to bax balance play a central role in ischemia-dependent apoptosis while angiotensin II and beta(1)-adrenergic-stimulation may be major causes of receptor-mediated apoptosis. Benefits due to treatment with ACE-inhibitors and beta-blockers appear to be in part due to reduced myocardial apoptosis. Moreover, infarct-related artery patency late after AMI may be a major determinant of myocardial apoptosis and clinical benefits deriving from an open artery late post AMI (the "open artery hypothesis") may be, at least in part, due to reduced myocardiocyte loss.