Sex-related resistance to myocardial ischemia-reperfusion injury is associated with high constitutive ARC expression

Sex differences in mortality and hospitalization in heart failure with preserved and mid-range ejection fraction: a systematic review and meta-analysis of cohort studies

Introduction

The influence of sex on the prognosis of heart failure with preserved or intermediate ejection fraction (HFpEF and HFmrEF) remains uncertain. This study aimed to investigate whether sex differences impact the prognosis of patients diagnosed with HFpEF and HFmrEF.

Methods

A comprehensive search across three databases (PubMed, the Cochrane Library, and Embase) was conducted to identify sex-related prognostic cohort studies focusing on HFpEF and HFmrEF. Risk estimates were synthesized using the random effects model. The analysis included 14 cohorts comprising 41,508 HFpEF patients (44.65% males) and 10,692 HFmrEF patients (61.79% males).

Results

Among HFpEF patients, men exhibited significantly higher rates of all-cause mortality (13 studies; hazard ratio (HR): 1.24, 95% confidence interval (CI): 1.15 to 1.33)) and cardiovascular disease mortality (5 studies; HR: 1.22, 95% CI: 1.14 to 1.31) compared to women. However, no significant difference was observed in HF admissions. For HFmrEF patients, men displayed notably higher all-cause mortality (HR: 1.21, 95% CI: 1.12 to 1.31) but no significant differences in cardiovascular mortality or HF admissions.

Discussion

These findings suggest that male patients diagnosed with HFpEF and HFmrEF may face a more unfavorable prognosis in terms of all-cause mortality. Variations were noted in cardiovascular mortality and HF admissions, indicating potential complexities in sex-related prognostic factors within these heart failure categories. In summary, male patients with HFpEF and HFmrEF may have a more unfavorable prognosis.

Sex Differences in Therapies against Myocardial Ischemia-Reperfusion Injury: From Basic Science to Clinical Perspectives

Mortality from myocardial infarction (MI) has declined over recent decades, which could be attributed in large part to improved treatment methods. Early reperfusion is the cornerstone of current MI treatment. However, reoxygenation via restored blood flow induces further damage to the myocardium, leading to ischemia-reperfusion injury (IRI). While experimental studies overwhelmingly demonstrate that females experience greater functional recovery from MI and decreased severity in the underlying pathophysiological mechanisms, the outcomes of MI with subsequent reperfusion therapy, which is the clinical correlate of myocardial IRI, are generally poorer for women compared with men. Distressingly, women are also reported to benefit less from current guideline-based therapies compared with men. These seemingly contradicting outcomes between experimental and clinical studies show a need for further investigation of sex-based differences in disease pathophysiology, treatment response, and a sex-specific approach in the development of novel therapeutic methods against myocardial IRI. In this literature review, we summarize the current knowledge on sex differences in the underlying pathophysiological mechanisms of myocardial IRI, including the roles of sex hormones and sex chromosomes. Furthermore, we address sex differences in pharmacokinetics, pharmacodynamics, and pharmacogenetics of current drugs prescribed to limit myocardial IRI. Lastly, we highlight ongoing clinical trials assessing novel pharmacological treatments against myocardial IRI and sex differences that may underlie the efficacy of these new therapeutic approaches.

Sex-Dependent Mechanisms of Cell Death Modalities in Cardiovascular Disease

Despite currently available therapies, cardiovascular diseases (CVD) are among the leading causes of death globally. Biological sex is a critical determinant of the occurrence, progression and overall outcome of CVD. However, the underlying mechanisms are incompletely understood. A hallmark of CVD is cell death. Based on the inability of the human heart to regenerate, loss of functional cardiac tissue can lead to irreversible detrimental effects. Here, we summarize current knowledge on how biological sex affects cell death-related mechanisms in CVD. Initially, we discuss apoptosis and necrosis, but we specifically focus on the relatively newly recognized programmed necrosis-like processes: pyroptosis and necroptosis. We also discuss the role of 17β-estradiol (E2) in these processes, particularly in terms of inhibiting pyroptotic and necroptotic signaling. We put forward that a better understanding of the effects of biological sex and E2 might lead to the identification of novel targets with therapeutic potential.

Protective Effect of Remote Ischemic Preconditioning against Myocardial Ischemia-Reperfusion Injury in Rats and Mice: A Systematic Review and Meta-Analysis

Background

Remote ischemic preconditioning (RIPC) has cardioprotective effects. This study was designed to evaluate the effectiveness and potential influencing factors of RIPC for myocardial ischemia-reperfusion injury (MIRI) in rats and mice.

Methods

The PubMed, Web of Science, Embase, and Cochrane Library databases were searched to identify animal model studies that explored the effect of RIPC on MIRI. The primary outcome was myocardial infarct size, and secondary outcomes included serum cardiac markers, vital signs, hemodynamic parameters, and TUNEL-positive cells. Quality was assessed using SYRCLE's Risk of Bias Tool.

Results

This systematic review and meta-analysis included 713 male animals from 37 studies. RIPC significantly protected against MIRI in small animal models by reducing infarct size, decreasing serum myocardial marker levels and cell death, and improving cardiac function. Subgroup analysis indicated that RIPC duration and sites influence the protective effect of RIPC on MIRI. Meta-regression suggested that study type and staining method might be sources of heterogeneity. The funnel plot, Egger's test, and Begg's test suggested the existence of publication bias, but results of the sensitivity analysis and nonparametric trim-and-fill method showed that the overall effect of RIPC on MIRI infarct size was robust.

Conclusions

RIPC significantly protected against MIRI in small animal models by reducing infarct size, decreasing serum myocardial markers and limiting cell death, and improving cardiac function. RIPC duration and site influence the protective effect of RIPC on MIRI, which contributes in reducing confounding factors and determines the best approach for human studies.

An Up-to-Date Article Regarding Particularities of Drug Treatment in Patients with Chronic Heart Failure

Since the prevalence of heart failure (HF) increases with age, HF is now one of the most common reasons for the hospitalization of elderly people. Although the treatment strategies and overall outcomes of HF patients have improved over time, hospitalization and mortality rates remain elevated, especially in developed countries where populations are aging. Therefore, this paper is intended to be a valuable multidisciplinary source of information for both doctors (cardiologists and general physicians) and pharmacists in order to decrease the morbidity and mortality of heart failure patients. We address several aspects regarding pharmacological treatment (including new approaches in HF treatment strategies [sacubitril/valsartan combination and sodium glucose co-transporter-2 inhibitors]), as well as the particularities of patients (age-induced changes and sex differences) and treatment (pharmacokinetic and pharmacodynamic changes in drugs; cardiorenal syndrome). The article also highlights several drugs and food supplements that may worsen the prognosis of HF patients and discusses some potential drug-drug interactions, their consequences and recommendations for health care providers, as well as the risks of adverse drug reactions and treatment discontinuation, as an interdisciplinary approach to treatment is essential for HF patients.

GSDMD-Mediated Cardiomyocyte Pyroptosis Promotes Myocardial I/R Injury

Supplemental Digital Content is available in the text.

Rationale:

Pyroptosis is a morphologically and mechanistically distinct form of cell death and is characterized by GSDMD (gasdermin D) or GSDME (gasdermin E)-mediated necrosis with excessive inflammatory factor release. Cardiomyocyte necrosis and inflammation play key roles in the pathophysiology of myocardial ischemia/reperfusion (I/R) injury. However, whether cardiomyocytes undergo pyroptosis and the underlying mechanism in myocardial I/R injury remain unclear.

Objective:

We aimed to investigate the role of pyroptosis in myocardial I/R injury.

Methods and Results:

In vivo and in vitro experiments were used to investigate pyroptosis of cardiomyocyte and the associated mechanisms during I/R injury. Wild-type, Myh6-Cre, and cardiomyocyte-specific GSDMD-deficient male mice were subjected to I/R. Human peripheral blood samples were collected from patients with acute ST-segment–elevation myocardial infarction or control patients at 0, 1, and 24 hours after percutaneous coronary intervention in our department. The serum levels of GSDMD were measured by ELISA. Hypoxia/reoxygenation induced cardiomyocyte pyroptosis and the release of mature IL (interleukin)-18 but not IL-1β, which mechanistically resulted from GSDMD cleavage by caspase-11 in cardiomyocytes. Furthermore, GSDMD gene deletion blocked hypoxia/reoxygenation-induced cardiomyocyte pyroptosis and IL-18 release. GSDMD and its pyroptosis-inducing N-terminal fragment were upregulated in myocardial tissues after I/R injury. Immunofluorescence analysis showed that GSDMD was mainly localized in cardiomyocytes. GSDMD deficiency in cardiomyocytes significantly reduced the I/R-induced myocardial infarct size. Moreover, increased GSDMD serum levels were detected in patients exhibiting I/R injury 1 hour after percutaneous coronary intervention for ST-segment–elevation myocardial infarction.

Conclusions:

Our results show that GSDMD-mediated cardiomyocyte pyroptosis is a key event during myocardial I/R injury and that the caspase-11/GSDMD pathway may be essential to this process. Additionally, GSDMD inhibition significantly reduces cardiomyocyte pyroptosis and I/R-induced myocardial injury.

Graphic Abstract:

A graphic abstract is available for this article.

Role of apoptosis repressor with caspase recruitment domain (ARC) in cell death and cardiovascular disease

Apoptosis repressor with caspase recruitment domain (ARC) is a highly effective and multifunctional inhibitor of apoptosis that is mainly expressed in postmitotic cells such as cardiomyocytes and skeletal muscle cells. ARC contains a C-terminal region rich in proline and glutamic acid residues and an N-terminal caspase recruitment domain (CARD). The CARD is originally described as a protein-binding motif that interacts with caspase through a CARD-CARD interaction. Initially, the inhibitory effect of ARC was only found in apoptosis, however, it was later found that ARC also played a regulatory role in other types of cell death. As a powerful cardioprotective factor, ARC can protect the heart by inhibiting the death of cardiomyocytes in various ways. ARC can reduce the cardiomyocyte apoptotic response to various stresses and injuries, including extrinsic apoptosis induced by death receptor ligands, cellular Ca²⁺ homeostasis and the dysregulation of endoplasmic reticulum (ER) stress, oxidative stress and hypoxia. In addition, changes in ARC transcription and translation levels in the heart can cause a series of physiological and pathological changes, and ARC can also perform corresponding functions through interactions with other molecules. Although there has been much research on ARC, the functional redundancy among proteins shows that ARC still has much research value. This review summarizes the molecular characteristics of ARC, its roles in the various death modes in cardiomyocytes and the roles of ARC in cardiac pathophysiology. This article also describes the potential therapeutic effect and research prospects of ARC.

Berry-Derived Polyphenols in Cardiovascular Pathologies: Mechanisms of Disease and the Role of Diet and Sex

Cardiovascular disease (CVD) prevalence, pathogenesis, and manifestation is differentially influenced by biological sex. Berry polyphenols target several signaling pathways pertinent to CVD development, including inflammation, oxidative stress, and cardiac and vascular remodeling, and there are innate differences in these pathways that also vary by sex. There is limited research systematically investigating sex differences in berry polyphenol effects on these pathways, but there are fundamental findings at this time that suggest a sex-specific effect. This review will detail mechanisms within these pathological pathways, how they differ by sex, and how they may be individually targeted by berry polyphenols in a sex-specific manner. Because of the substantial polyphenolic profile of berries, berry consumption represents a promising interventional tool in the treatment and prevention of CVD in both sexes, but the mechanisms in which they function within each sex may vary.

Gender difference in the impact of Ischaemic heart disease on heart failure

BACKGROUND

Although the impact of ischaemic heart disease (IHD) on heart failure (HF) is evolving, there is uncertainty about the role of IHD in determining the risk of clinical outcomes by gender. This study evaluated the gender difference in the impact of IHD on long-term clinical outcomes in patients with heart failure reduced ejection fraction (HFrEF).

METHODS

Study data were obtained from a nationwide registry, which is a prospective multicentre cohort that included 3200 patients who were hospitalized for HF. A total of 1638 patients with HFrEF were classified by gender. The primary outcome was all-cause death during follow-up.

RESULTS

In total, 133 women (18.9%) died and 168 men (18.0%) died during the follow-up (median, 489 days). Women with HFrEF with IHD had a significantly lower cumulative survival rate than women without IHD at the long-term follow-up (74.8% vs 84.9%, log-rank P = .001). However, the survival rate was not different in men with HFrEF with IHD compared with men without IHD. A Cox regression analysis showed that IHD had a 1.43-fold increased risk for all-cause mortality independently in women after adjusting for confounding factors (odds ratio 1.43, 95% confidence interval 1.058-1.929, P = .020).

CONCLUSION

Ischaemic heart disease was an independent risk factor for long-term mortality in women with HFrEF. IHD should be actively evaluated in women with HF for predicting clinical outcomes and initiating appropriate treatment. Women with HF caused by IHD should be treated more meticulously to avoid a poor prognosis.

Lower Post Myocardial Infarction Mortality Among Women Treated at Veterans Affairs Hospitals Compared to Men

BACKGROUND

There is conflicting evidence about whether mortality after myocardial infarction is higher among women than among men. This study aimed to compare sex differences in post myocardial infarction mortality in the Veterans Affairs system, a setting where the predominant subjects are men.

MATERIALS AND METHODS

The Veterans Affairs Corporate Data Warehouse inpatient and laboratory chemistry databases were used to identify patients diagnosed with acute myocardial infarction from inpatient records from January 1st, 2005 to April 25th, 2015. Mortality data was obtained through the Veterans Affairs death registry.

RESULTS

A total of 130,241 patients were identified; 127,711 men (98%) and 2,530 women (2%). Men typically had more comorbidities including congestive heart failure (54% vs. 46%, P value < 0.001), diabetes mellitus (54% vs. 48%, P value < 0.001), and chronic kidney disease (39% vs. 28%, P value < 0.001). The peak troponin-I was significantly higher among men (16.0 vs. 10.7 ng/mL, P value = 0.03). The mean follow-up time was 1490.67 ± 8 days. After adjusting for differences in demographics and comorbidities, women had a significantly lower risk of mortality (hazard ration [HR]: 0.747, P value < 0.0001) as compared to men.

CONCLUSIONS

In a health care system where the predominant subjects are men, women had better short- and long-term survival than men after an acute myocardial infarction. Further investigation is warranted to determine the reasons behind the improved outcomes in women post myocardial infarction in the veteran population.

Sex Differences in Heart Failure

Heart failure (HF) represents a global pandemic health problem with a high impact on health-care costs, affecting about 26 million adults worldwide. The overall HF prevalence and incidence are ~2% and ~0.2% per year, respectively, in Western countries, with half of the HF population with reduced ejection fraction (HFpEF) and half with preserved (HFpEF) or mid-range ejection fraction (HFmrEF). Sex differences may exist in HF. More males have HFrEF or HFmrEF and an ischemic etiology, whereas more females have HFpEF and hypertension, diastolic dysfunction, and valvular pathologies as HF etiologies. Females are generally older, have a higher EF, higher frequency of HF-related symptoms, and lower NYHA functional status. Generally, it is observed that female HF patients tend to have more comorbidities such as atrial fibrillation, diabetes, hypertension, anemia, iron deficiency, renal disease, arthritis, frailty, depression, and thyroid abnormalities. However, overall, females have better prognosis in terms of mortality and hospitalization risk compared with men, regardless of EF. Potential sex differences in HF characteristics may be underestimated because of the underrepresentation of females in cardiovascular research and, in particular, the sex imbalance in clinical trial enrollment may avoid to identify sex-specific differences in treatments' benefit.

Mechanistic Pathways of Sex Differences in Cardiovascular Disease

Major differences between men and women exist in epidemiology, manifestation, pathophysiology, treatment, and outcome of cardiovascular diseases (CVD), such as coronary artery disease, pressure overload, hypertension, cardiomyopathy, and heart failure. Corresponding sex differences have been studied in a number of animal models, and mechanistic investigations have been undertaken to analyze the observed sex differences. We summarize the biological mechanisms of sex differences in CVD focusing on three main areas, i.e., genetic mechanisms, epigenetic mechanisms, as well as sex hormones and their receptors. We discuss relevant subtypes of sex hormone receptors, as well as genomic and nongenomic, activational and organizational effects of sex hormones. We describe the interaction of sex hormones with intracellular signaling relevant for cardiovascular cells and the cardiovascular system. Sex, sex hormones, and their receptors may affect a number of cellular processes by their synergistic action on multiple targets. We discuss in detail sex differences in organelle function and in biological processes. We conclude that there is a need for a more detailed understanding of sex differences and their underlying mechanisms, which holds the potential to design new drugs that target sex-specific cardiovascular mechanisms and affect phenotypes. The comparison of both sexes may lead to the identification of protective or maladaptive mechanisms in one sex that could serve as a novel therapeutic target in one sex or in both.

Autophagy Regulatory Network - a systems-level bioinformatics resource for studying the mechanism and regulation of autophagy

Autophagy is a complex cellular process having multiple roles, depending on tissue, physiological, or pathological conditions. Major post-translational regulators of autophagy are well known, however, they have not yet been collected comprehensively. The precise and context-dependent regulation of autophagy necessitates additional regulators, including transcriptional and post-transcriptional components that are listed in various datasets. Prompted by the lack of systems-level autophagy-related information, we manually collected the literature and integrated external resources to gain a high coverage autophagy database. We developed an online resource, Autophagy Regulatory Network (ARN; http://autophagy-regulation.org), to provide an integrated and systems-level database for autophagy research. ARN contains manually curated, imported, and predicted interactions of autophagy components (1,485 proteins with 4,013 interactions) in humans. We listed 413 transcription factors and 386 miRNAs that could regulate autophagy components or their protein regulators. We also connected the above-mentioned autophagy components and regulators with signaling pathways from the SignaLink 2 resource. The user-friendly website of ARN allows researchers without computational background to search, browse, and download the database. The database can be downloaded in SQL, CSV, BioPAX, SBML, PSI-MI, and in a Cytoscape CYS file formats. ARN has the potential to facilitate the experimental validation of novel autophagy components and regulators. In addition, ARN helps the investigation of transcription factors, miRNAs and signaling pathways implicated in the control of the autophagic pathway. The list of such known and predicted regulators could be important in pharmacological attempts against cancer and neurodegenerative diseases.

Sex-based differences in cardiac ischaemic injury and protection: therapeutic implications

Ischaemic heart disease (IHD) is the most frequent cause of mortality among men and women. Many epidemiological studies have demonstrated that premenopausal women have a reduced risk for IHD compared with their male counterparts. The incidence of IHD in women increases after menopause, suggesting that IHD is related to declining oestrogen levels. Experimental observations have confirmed the results of epidemiological studies investigating sex-specific differences in cardiac tolerance to ischaemia. Female sex appears also to favourably influence cardiac remodelling after ischaemia/reperfusion injury. Furthermore, sex-related differences in ischaemic tolerance of the adult myocardium can be influenced by interventions during the early phases of ontogenetic development. Detailed mechanisms of these sex-related differences remain unknown; however, they involve the genomic and non-genomic effects of sex steroid hormones, particularly the oestrogens, which have been the most extensively studied. Although the protective effects of oestrogen have many potential therapeutic implications, clinical trials have shown that oestrogen replacement in postmenopausal women may actually increase the incidence of IHD. The results of these trials have illustrated the complexity underlying the mechanisms involved in sex-related differences in cardiac tolerance to ischaemia. Sex-related differences in cardiac sensitivity to ischaemia/reperfusion injury may also influence therapeutic strategies in women with acute coronary syndrome. Women undergo coronary intervention less frequently and a lower proportion of women receive evidence-based therapy compared with men. Although our understanding of this important topic has increased in recent years, there is an urgent need for intensive experimental and clinical research to develop female-specific therapeutic strategies. Only then we will be able to offer patients better evidence-based treatment, a better quality of life and lower mortality.

The role of sex differences in autophagy in the heart during coxsackievirus B3-induced myocarditis

Under normal conditions, autophagy maintains cardiomyocyte health and integrity through turnover of organelles. During stress, oxygen and nutrient deprivation, or microbial infection, autophagy prolongs cardiomyocyte survival. Sex differences in induction of cell death may to some extent explain the disparity between the sexes in many human diseases. However, sex differences in gene expression, which regulate cell death and autophagy, were so far not taken in consideration to explain the sex bias of viral myocarditis. Coxsackievirus B3 (CVB3)-induced myocarditis is a sex-biased disease, with females being substantially less susceptible than males and sex hormones largely determine this bias. CVB3 was shown to induce and subvert the autophagosome for its optimal viral RNA replication. Gene expression analysis on mouse and human, healthy and CVB3-infected, cardiac samples of both sexes, suggests sex differences in autophagy-related gene expression. This review discusses the aspects of sex bias in autophagy induction in cardiomyocytes.

Implications of myocardial reperfusion on survival in women versus men with acute myocardial infarction undergoing primary coronary intervention

We evaluated the effects of myocardial perfusion after primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) on gender-based mortality rates. Research has demonstrated a gender-specific response of cardiomyocytes to ischemia and a potential increase in myocardial salvage in women compared with men. Myocardial blush grade (MBG), an angiographic surrogate of myocardial perfusion, is an independent predictor of early and late survival after AMI. Whether the incidence and prognosis of myocardial perfusion differs according to gender among patients with AMI undergoing PCI is unknown. MBG and short- and long-term mortality were evaluated in 1,301 patients (male = 935; female = 366) with AMI randomized to primary angioplasty ± abciximab versus stent ± abciximab. Following PCI, >96% of patients achieved final Thrombolysis In Myocardial Infarction 3 flow, of which MBG 2/3 was present in 58.3% of women versus 51.1% of men (p = 0.02). Worse MBG was an independent predictor of mortality in women at 30 days (7.4% for MBG 0/1 vs 2.4% for MBG 2/3, p = 0.04) and at 1-year (11.0% for MBG 0/1 vs 3.4% for MBG 2/3, p = 0.01); however, MBG was not associated with differences in mortality for men. In conclusion, impaired myocardial perfusion following PCI for AMI, indicated by worse MBG, is an independent predictor of early and late mortality in women but not in men. These findings imply an enhanced survival benefit from restoring myocardial perfusion for women compared with men during primary angioplasty and may have clinical implications for interventional strategies in women.

Apoptosis and autophagy contribute to gender difference in cardiac ischemia-reperfusion induced injury in rats

AIMS

Gender difference in cardiac ischemia-reperfusion (IR) induced injury has been reported in animal models. However, a large-scale clinical trial found an increase in cardiovascular incidents in women with hormone replacement therapy. The present study is aimed to explore possible mechanisms of gender difference in cardiac IR induced injury.

MAIN METHODS

Male and female Sprague-Dawley rats were subjected to a 30-min coronary arterial occlusion followed by reperfusion. The infarct size and apoptotic cell number at 24h after reperfusion were significantly lower in female rats than in male rats.

KEY FINDINGS

Male rats expressed higher anti-apoptotic protein Bcl2 levels compared with female rats under physiological conditions. However, levels of Bcl2 were reduced significantly after IR in male rats but not in, female rats. Levels of pro-apoptotic protein, Bax and phospho-p38, showed similar under physiological conditions. In response to IR expression of Bax was markedly reduced in female rats but not in male rats, and expression of phospho-p38 was significantly increased in male rats but not in female rats. In addition, female rats showed marked increase of autophagy marker, ratio of LC3B to LC3A, while male rats significantly decreased the ratio in response to IR.

SIGNIFICANCE

Gender difference in IR injury is due to the different regulation of anti-apoptotic protein, pro-apoptotic protein and autophagy protein levels in male rats and levels in female rats. Our results provide better understanding of sex differences in cardiac IR injury.

Gender differences in the pathophysiology, clinical presentation, and outcomes of ischemic heart failure

Despite advances in the treatment of acute myocardial infarction (MI), heart failure (HF) remains a frequent acute and long-term outcome of ischemic heart disease (IHD). In response to acute coronary ischemia, women are relatively protected from apoptosis, and experience less adverse cardiac remodeling than men, frequently resulting in preservation of left ventricular size and ejection fraction. Despite these advantages, women are at increased risk for HF- complicating acute MI when compared with men. However, women with HF retain a survival advantage over men with HF, including a decreased risk of sudden death. Sex-specific treatment of HF has been hindered by historical under-representation of women in clinical trials, though recent work has suggested that women may have a differential response to some therapies such as cardiac resynchronization. This review highlights the sex differences in the pathophysiology, clinical presentation and outcomes of ischemic heart failure and discusses key areas worthy of further investigation.

Hypoxia/reoxygenation cardiac injury and regeneration in zebrafish adult heart

Aims

the adult zebrafish heart regenerates spontaneously after injury and has been used to study the mechanisms of cardiac repair. However, no zebrafish model is available that mimics ischemic injury in mammalian heart. We developed and characterized zebrafish cardiac injury induced by hypoxia/reoxygenation (H/R) and the regeneration that followed it.

Methods and Results

adult zebrafish were kept either in hypoxic (H) or normoxic control (C) water for 15 min; thereafter fishes were returned to C water. Within 2–6 hours (h) after reoxygenation there was evidence of cardiac oxidative stress by dihydroethidium fluorescence and protein nitrosylation, as well as of inflammation. We used Tg(cmlc2:nucDsRed) transgenic zebrafish to identify myocardial cell nuclei. Cardiomyocyte apoptosis and necrosis were evidenced by TUNEL and Acridine Orange (AO) staining, respectively; 18 h after H/R, 9.9±2.6% of myocardial cell nuclei were TUNEL⁺ and 15.0±2.5% were AO⁺. At the 30-day (d) time point myocardial cell death was back to baseline (n = 3 at each time point). We evaluated cardiomyocyte proliferation by Phospho Histone H3 (pHH3) or Proliferating Cell Nuclear Antigen (PCNA) expression. Cardiomyocyte proliferation was apparent 18–24 h after H/R, it achieved its peak 3–7d later, and was back to baseline at 30d. 7d after H/R 17.4±2.3% of all cardiomyocytes were pHH3⁺ and 7.4±0.6% were PCNA⁺ (n = 3 at each time point). Cardiac function was assessed by 2D-echocardiography and Ventricular Diastolic and Systolic Areas were used to compute Fractional Area Change (FAC). FAC decreased from 29.3±2.0% in normoxia to 16.4±1.8% at 18 h after H/R; one month later ventricular function was back to baseline (n = 12 at each time point).

Conclusions

zebrafish exposed to H/R exhibit evidence of cardiac oxidative stress and inflammation, myocardial cell death and proliferation. The initial decrease in ventricular function is followed by full recovery. This model more closely mimics reperfusion injury in mammals than other cardiac injury models.

Sex differences in animal models for cardiovascular diseases and the role of estrogen

Clinical findings show sex differences in the manifestation of a number of cardiovascular diseases (CVD). However, the underlying molecular mechanisms are incompletely understood. Multiple animal models suggest sex differences in the manifestation of CVD, and provide strong experimental evidence that different major pathways are regulated in a sex-specific manner. In most animal studies females display a lower mortality, less severe hypertrophy, and better preserved cardiac function compared with male counterparts. The data support the hypothesis that female sex and/or the sex hormone estrogen (17β-estradiol; E2) may contribute to the sexual dimorphism in the heart and to a better outcome of cardiac diseases in females. To improve our understanding of the sex-based molecular and cellular mechanisms of CVD and to develop new therapeutic strategies, the use of appropriate animal models is essential. This review highlights recent findings from animal models relevant for studying the mechanisms of sexual dimorphisms in the healthy and diseased heart, focusing on physiological hypertrophy (exercise), pathological hypertrophy (volume and pressure overload induced hypertrophy), and heart failure (myocardial infarction). Furthermore, the potential effects of E2 in these models will be discussed.

Apoptosis repressor with caspase recruitment domain, a multifunctional modulator of cell death

Apoptosis repressor with caspase recruitment domain (ARC) is a highly potent and multifunctional inhibitor of apoptosis that is physiologically expressed predominantly in post-mitotic cells such as cardiomyocytes, skeletal muscle cells and neurons. ARC was also found to be up-regulated in many forms of malignant tumours. ARC impairs the cellular apoptotic responsiveness to a wide range of stresses and insults, including extrinsic apoptosis initiation via death receptor ligands, dysregulation of cellular Ca²⁺ homeostasis and endoplasmatic reticulum (ER) stress, genotoxic drugs, ionizing radiation, oxidative stress and hypoxia. ARC is subject to both transcriptional and post-translational regulation and exhibits its function through a multitude of molecular interactions with upstream transducers of apoptosis signals. This review summarizes, structures and comments on the published knowledge regarding ARC and its roles in modulating apoptotic cell death responsiveness in physiological and pathophysiological contexts.

Trends in acute myocardial infarction treatment between 1998 and 2007 in a Belgian area (Charleroi)

BACKGROUND/OBJECTIVES

To describe the evolution of the therapeutic practices over 10 years of follow-up of acute myocardial infarction (AMI) in Charleroi and to analyse the factors influencing the choice of treatments and the mortality of these patients.

METHODS

The Charleroi register of ischaemic cardiopathies is the oldest register of infarctions in the French-speaking community of Belgium and is one of the very rare registers that allows identifying tendencies over 25 years. Analyses presented hereafter relate only patients in the 25-69-year age range over time from 1998 to 2007. The data were analysed in five periods of 2 years. Treatment evolutions over time were analysed using chi-squared tests for trend and logistic regression analyses identify factors influencing the type of treatment.

RESULTS

The present study shows a marked increase in the utilization of percutaneous transluminal coronary angioplasty (PTCA) between 1998-1999 and 2006-2007. The use of thrombolytic agents on approximately one-third of the patients treated remained fairly stable between 1998 and 2007. A lower proportion of patients with a history of AMI received thrombolytic agents. Thrombolysis seems beneficial for men and without effect for women. The use of β-blockers continued to increase until the 2000-2001 period and remained fairly stable for the two following periods. 42% of patients were administered three medications (angiotensin-converting enzyme inhibitors, antiplatelet drugs, and β-blockers). Association of PTCA with antiplatelet drugs, β-blockers, and thrombolysis was observed for 58.7, 50.6, and 25.7%, respectively. These associations were still observed after adjustment for gender, age, and comorbidity. The factors associated with fatality were specifically old-aged patients, antecedents of diabetes, hypercholesterolaemia and oral antiplatelet drugs, and β-blockers therapies and PTCA.

CONCLUSIONS

The evolution of the therapeutic data on AMI in this register confirms the use and the efficacy of thrombolytic therapy. PTCA becomes the main coronary reperfusion treatment with less risk of bleeding. Angiotensin-converting enzyme inhibitors were without effect on mortality.