Ramipril restores PPARβ/δ and PPARγ expressions and reduces cardiac NADPH oxidase but fails to restore cardiac function and accompanied myosin heavy chain ratio shift in severe anthracycline-induced cardiomyopathy in rat

Angiotensin Regulation of Vascular Homeostasis: Exploring the Role of ROS and RAS Blockers

Extensive research has been conducted to elucidate and substantiate the crucial role of the Renin-Angiotensin System (RAS) in the pathogenesis of hypertension, cardiovascular disorders, and renal diseases. Furthermore, the role of oxidative stress in maintaining vascular balance has been well established. It has been observed that many of the cellular effects induced by Angiotensin II (Ang II) are facilitated by reactive oxygen species (ROS) produced by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. In this paper, we present a comprehensive overview of the role of ROS in the physiology of human blood vessels, specifically focusing on its interaction with RAS. Moreover, we delve into the mechanisms by which clinical interventions targeting RAS influence redox signaling in the vascular wall.

Beneficial Effects of Probiotic Bifidobacterium longum in a Lithium-Pilocarpine Model of Temporal Lobe Epilepsy in Rats

Epilepsy is a challenging brain disorder that is often difficult to treat with conventional therapies. The gut microbiota has been shown to play an important role in the development of neuropsychiatric disorders, including epilepsy. In this study, the effects of Bifidobacterium longum, a probiotic, on inflammation, neuronal degeneration, and behavior are evaluated in a lithium-pilocarpine model of temporal lobe epilepsy (TLE) induced in young adult rats. B. longum was administered orally at a dose of 10⁹ CFU/rat for 30 days after pilocarpine injection. The results show that B. longum treatment has beneficial effects on the TLE-induced changes in anxiety levels, neuronal death in the amygdala, and body weight recovery. In addition, B. longum increased the expression of anti-inflammatory and neuroprotective genes, such as Il1rn and Pparg. However, the probiotic had little effect on TLE-induced astrogliosis and microgliosis and did not reduce neuronal death in the hippocampus and temporal cortex. The study suggests that B. longum may have a beneficial effect on TLE and may provide valuable insights into the role of gut bacteria in epileptogenesis. In addition, the results show that B. longum may be a promising drug for the comprehensive treatment of epilepsy.

Infliximab substantially re-silenced Wnt/β-catenin signaling and ameliorated doxorubicin-induced cardiomyopathy in rats

The release of inflammatory cytokines, namely tumor necrosis factor-α (TNF-α), plays an important role in the pathogenesis of cardiomyopathy. TNF-α increases in plasma and in myocardium of heart failure patients. We aimed to investigate the role of TNF-α inhibitor (infliximab; IFX) in regulating dilated cardiomyopathy (DCM) induced in rats. DCM was induced in rats by doxorubicin (DOX; 3.5 mg. kg-1 , i.p) twice weekly for 3 weeks (21 mg. kg-1 cumulative dose). DCM rats were treated with RPL (1 mg. kg-1 orally, daily), IFX (5 mg. kg-1 ; i.p. once) or their combination for 4 weeks starting next day of last DOX dose. Echocardiography was conducted followed by a collection of blood and left ventricle (LV) for biochemical and histological investigations. DCM rats revealed deteriorated cardiac function (increased CK-MB activity, LVIDs, LVIDd, ESV, and EDV, while decreased EF% and FS%), hypertrophy (increased HW/TL, β-MHC, and α-actin), inflammation (increased IL-1β, IL-6, and TNF-α). The activation of Wnt/β-catenin along with increased gene expression of RAS components (RENIN, ACE, and AT1) were evident. LV architecture also revealed abnormalities and some degree of fibrosis. Treatment with RPL and/or IFX suppressed TNF-α and consequently improved most of these parameters suppressing Wnt/β-catenin/RAS axis. Combined RPL and IFX treatment was the best among all treatments. In conclusion, Wnt/β-catenin/RAS axis is implicated in DOX-induced cardiomyopathy. The upstream TNF-α was proved for the first time in-vivo to stimulate this axis where its inhibition by RPL or IFX prevented DCM. Targeting this axis at two points using RPL and IFX showed better therapeutic efficacy.

Pharmacological Utility of PPAR Modulation for Angiogenesis in Cardiovascular Disease

Peroxisome proliferator activated receptors, including PPARα, PPARβ/δ, and PPARγ, are ligand-activated transcription factors belonging to the nuclear receptor superfamily. They play important roles in glucose and lipid metabolism and are also supposed to reduce inflammation and atherosclerosis. All PPARs are involved in angiogenesis, a process critically involved in cardiovascular pathology. Synthetic specific agonists exist for all PPARs. PPARα agonists (fibrates) are used to treat dyslipidemia by decreasing triglyceride and increasing high-density lipoprotein (HDL) levels. PPARγ agonists (thiazolidinediones) are used to treat Type 2 diabetes mellitus by improving insulin sensitivity. PPARα/γ (dual) agonists are supposed to treat both pathological conditions at once. In contrast, PPARβ/δ agonists are not in clinical use. Although activators of PPARs were initially considered to have favorable effects on the risk factors for cardiovascular disease, their cardiovascular safety is controversial. Here, we discuss the implications of PPARs in vascular biology regarding cardiac pathology and focus on the outcomes of clinical studies evaluating their benefits in cardiovascular diseases.

Alterations in gut microbiota and metabolites associated with altitude-induced cardiac hypertrophy in rats during hypobaric hypoxia challenge

The gut microbiota is involved in host responses to high altitude. However, the dynamics of intestinal microecology and their association with altitude-related illness are poorly understood. Here, we used a rat model of hypobaric hypoxia challenge to mimic plateau exposure and monitored the gut microbiome, short-chain fatty acids (SCFAs), and bile acids (BAs) over 28 d. We identified weight loss, polycythemia, and pathological cardiac hypertrophy in hypoxic rats, accompanied by a large compositional shift in the gut microbiota, which is mainly driven by the bacterial families of Prevotellaceae, Porphyromonadaceae, and Streptococcaceae. The aberrant gut microbiota was characterized by increased abundance of the Parabacteroides, Alistipes, and Lactococcus genera and a larger Bacteroides to Prevotella ratio. Trans-omics analyses showed that the gut microbiome was significantly correlated with the metabolic abnormalities of SCFAs and BAs in feces, suggesting an interaction network remodeling of the microbiome-metabolome after the hypobaric hypoxia challenge. Interestingly, the transplantation of fecal microbiota significantly increased the diversity of the gut microbiota, partially inhibited the increased abundance of the Bacteroides and Alistipes genera, restored the decrease of plasma propionate, and moderately ameliorated cardiac hypertrophy in hypoxic rats. Our results provide an insight into the longitudinal changes in intestinal microecology during the hypobaric hypoxia challenge. Abnormalities in the gut microbiota and microbial metabolites contribute to the development of high-altitude heart disease in rats.

Cardiac Toxicity From Adjuvant Targeting Treatment for Breast Cancer Post-Surgery

Breast cancer is one of the most prevalent types of cancers worldwide, especially for females. Surgery is the preferred treatment for breast cancer, and various postoperative adjuvant therapies can be reasonably used according to different pathological characteristics, especially traditional radiotherapy, chemotherapy, and endocrine therapy. In recent years, targeting agent therapy has also become one of the selective breast cancer treatment strategies, including anti-HER-2 drugs, CDK4/6 inhibitor, poly ADP-ribose polymerase inhibitor, PI3K/AKT/mTOR pathway inhibitor, ER targeting drugs, and aromatase inhibitor. Because of the different pathologic mechanisms of these adjuvant therapies, each of the strategies may cause cardiotoxicity in clinic. The cardiac adverse events of traditional endocrine therapy, radiotherapy, and chemotherapy for breast cancer have been widely detected in clinic; however, the targeting therapy agents have been paid more attention with the extension of application. This review will summarize the cardiac toxicity of various adjuvant therapies for breast cancer, especially for targeting drug therapy.

Primary prevention of chronic anthracycline cardiotoxicity with ACE inhibitor is temporarily effective in rabbits, but benefits wane in post-treatment follow-up

Angiotensin-converting enzyme inhibitors (ACEis) have been used to treat anthracycline-induced cardiac dysfunction, and they appear beneficial for secondary prevention in high-risk patients. However, it remains unclear whether they truly prevent anthracycline-induced cardiac damage and provide long-lasting cardioprotection. This study aimed to examine the cardioprotective effects of perindopril on chronic anthracycline cardiotoxicity in a rabbit model previously validated with the cardioprotective agent dexrazoxane with focus on post-treatment follow-up (FU). Chronic cardiotoxicity was induced by daunorubicin (3 mg/kg/week for 10 weeks). Perindopril (0.05 mg/kg/day) was administered before and throughout chronic daunorubicin treatment. After the completion of treatment, significant benefits were observed in perindopril co-treated animals, particularly full prevention of daunorubicin-induced mortality and prevention or significant reductions in cardiac dysfunction, plasma cardiac troponin T levels, morphological damage, and most of the myocardial molecular alterations. However, these benefits significantly waned during 3 weeks of drug-free FU, which was not salvageable by administering a higher perindopril dose. In the longer (10-week) FU period, further worsening of left ventricular function and morphological damage occurred together with heart failure-related mortality. Continued perindopril treatment in the FU period did not reverse this trend but prevented heart failure-related mortality and reduced the severity of the progression of cardiac damage. These findings contrasted with the robust long-lasting protection observed previously for dexrazoxane in the same model. Hence, in this study, perindopril provided only temporary control of anthracycline cardiotoxicity development, which may be associated with the lack of effects on anthracycline-induced and topoisomerase II beta-dependent DNA damage responses in the heart.

Alternative RAS in Various Hypoxic Conditions: From Myocardial Infarction to COVID-19

Alternative branches of the classical renin–angiotensin–aldosterone system (RAS) represent an important cascade in which angiotensin 2 (AngII) undergoes cleavage via the action of the angiotensin-converting enzyme 2 (ACE2) with subsequent production of Ang(1-7) and other related metabolites eliciting its effects via Mas receptor activation. Generally, this branch of the RAS system is described as its non-canonical alternative arm with counterbalancing actions to the classical RAS, conveying vasodilation, anti-inflammatory, anti-remodeling and anti-proliferative effects. The implication of this branch was proposed for many different diseases, ranging from acute cardiovascular conditions, through chronic respiratory diseases to cancer, nonetheless, hypoxia is one of the most prominent common factors discussed in conjugation with the changes in the activity of alternative RAS branches. The aim of this review is to bring complex insights into the mechanisms behind the various forms of hypoxic insults on the activity of alternative RAS branches based on the different duration of stimuli and causes (acute vs. intermittent vs. chronic), localization and tissue (heart vs. vessels vs. lungs) and clinical relevance of studied phenomenon (experimental vs. clinical condition). Moreover, we provide novel insights into the future strategies utilizing the alternative RAS as a diagnostic tool as well as a promising pharmacological target in serious hypoxia-associated cardiovascular and cardiopulmonary diseases.

Deregulated glutamate to pro-collagen conversion is associated with adverse outcome in lung cancer and may be targeted by renin-angiotensin-aldosterone system (RAS) inhibition

BACKGROUND

The tumor-microenvironment (TME) represents an attractive therapeutic target in NSCLC and plays an important role for efficacy of cancer therapeutics. We hypothesized that upregulation of collagen synthesis might be associated with adverse outcome in NSCLC. Literature evidence suggests that renin-angiotensin system inhibitors (RASi) decrease collagen deposition. Therefore, we aimed to explore the prognostic role of RASi intake and their influence on the TME in NSCLC.

METHODS

Four publicly available datasets were used to evaluate the impact of key enzymes involved in collagen biosynthesis. To investigate the influence of RASi intake on the TME and prognosis we evaluated a cohort of metastatic NSCLC patients and performed histopathological characterization of the TME. A three-dimensional microtissue in vitro model was developed to define the impact of RASi on collagen synthesis.

RESULTS

Expression of three genes of the collagen synthesis pathway, ALDH18A1, PLOD2 and P4HA1, was upregulated in NSCLC compared to normal lung tissue and linked to shortened overall survival in all investigated cohorts. Together, these genes formed a 'Collagen Signature' which represents an independent unfavourable prognostic factor in two NSCLC cohorts and was linked to alterations of the extracellular matrix deposition and cell cycle pathways. In the cohort of metastatic NSCLC, RASi intake was linked to improved overall response rate and survival. Exploratory in vitro experiments revealed that RASi led to a dose dependent reduction of collagen deposition and degradation of three-dimensional lung cancer cell spheroids.

CONCLUSION

We demonstrate that collagen synthesis is a key upregulated process in the NSCLC TME and its transcriptional readout, the three gene Collagen Signature is independently associated with poor outcome. Pharmacological targeting of this pathways e.g. by RASi bears potential of improving outcome in NSCLC.

Molecular mechanisms of anthracycline cardiovascular toxicity

Anthracyclines are effective chemotherapeutic agents, commonly used in the treatment of a variety of hematologic malignancies and solid tumors. However, their use is associated with a significant risk of cardiovascular toxicities and may result in cardiomyopathy and heart failure. Cardiomyocyte toxicity occurs via multiple molecular mechanisms, including topoisomerase II-mediated DNA double-strand breaks and reactive oxygen species (ROS) formation via effects on the mitochondrial electron transport chain, NADPH oxidases (NOXs), and nitric oxide synthases (NOSs). Excess ROS may cause mitochondrial dysfunction, endoplasmic reticulum stress, calcium release, and DNA damage, which may result in cardiomyocyte dysfunction or cell death. These pathophysiologic mechanisms cause tissue-level manifestations, including characteristic histopathologic changes (myocyte vacuolization, myofibrillar loss, and cell death), atrophy and fibrosis, and organ-level manifestations including cardiac contractile dysfunction and vascular dysfunction. In addition, these mechanisms are relevant to current and emerging strategies to diagnose, prevent, and treat anthracycline-induced cardiomyopathy. This review details the established and emerging data regarding the molecular mechanisms of anthracycline-induced cardiovascular toxicity.

Arrhythmogenic right ventricular cardiomyopathy and sports activity: from molecular pathways in diseased hearts to new insights into the athletic heart mimicry

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited disease associated with a high risk of sudden cardiac death. Among other factors, physical exercise has been clearly identified as a strong determinant of phenotypic expression of the disease, arrhythmia risk, and disease progression. Because of this, current guidelines advise that individuals with ARVC should not participate in competitive or frequent high-intensity endurance exercise. Exercise-induced electrical and morphological para-physiological remodelling (the so-called 'athlete's heart') may mimic several of the classic features of ARVC. Therefore, the current International Task Force Criteria for disease diagnosis may not perform as well in athletes. Clear adjudication between the two conditions is often a real challenge, with false positives, that may lead to unnecessary treatments, and false negatives, which may leave patients unprotected, both of which are equally inacceptable. This review aims to summarize the molecular interactions caused by physical activity in inducing cardiac structural alterations, and the impact of sports on arrhythmia occurrence and other clinical consequences in patients with ARVC, and help the physicians in setting the two conditions apart.

Isolated downregulation of HCN2 in ventricles of rats with streptozotocin-induced diabetic cardiomyopathy

BACKGROUND

In spite of disrupted repolarization of diabetic heart, some studies report less tendency of diabetic heart to develop ventricular arrhythmias suggesting effective compensatory mechanism. We hypothesized that myocardial alterations in HCN2 and HCN4 channels occur under hyperglycaemia.

METHODS

Diabetes was induced in rats using a single injection of streptozotocin (STZ; 55 mg/kg body weight, i.p.). Basal ECG was measured. Expression of mRNA for HCN channels, potassium channels and microRNA 1 and 133a were measured in ventricular tissues. Protein expression of HCN2 channel isoform was assessed in five different regions of the heart by western blotting. Differentiated H9c2 cell line was used to examine HCN channels expression under hyperglycaemia in vitro.

RESULTS

Six weeks after STZ administration, heart rate was reduced, QRS complex duration, QT interval and T-wave were prolonged in diabetic rats compared to controls. mRNA and protein expressions of HCN2 decreased exclusively in the ventricles of diabetic rats. HCN2 expression levels in atria of STZ rats and H9c2 cells treated with excess of glucose were not changed. MicroRNA levels were stable in STZ rat hearts. We found significantly decreased mRNA levels of several potassium channels participating in repolarization, namely Kcnd2 (Ito1), Kcnh2 (IKr), Kcnq1 (IKs) and Kcnj11 (IKATP).

CONCLUSIONS

This result together with downregulated HCN2 channels suggest that HCN channels might be an integral part of ventricular electric remodelling and might play a role in cardiac repolarization projected in altered arrhythmogenic profile of diabetic heart.

The tyrosine kinase inhibitor crizotinib influences blood glucose and mRNA expression of GLUT4 and PPARs in the heart of rats with experimental diabetes

Tyrosine kinases inhibitors (TKIs) may alter glycaemia and may be cardiotoxic with importance in the diabetic heart. We investigated the effect of multi-TKI crizotinib after short-term administration on metabolic modulators of the heart of diabetic rats. Experimental diabetes mellitus (DM) was induced by streptozotocin (STZ; 80 mg·kg^-1, i.p.), and controls (C) received vehicle. Three days after STZ, crizotinib (STZ+CRI; 25 mg·kg^-1 per day p.o.) or vehicle was administered for 7 days. Blood glucose, C-peptide, and glucagon were assessed in plasma samples. Receptor tyrosine kinases (RTKs), cardiac glucose transporters, and peroxisome proliferator-activated receptors (PPARs) were determined in rat left ventricle by RT-qPCR method. Crizotinib moderately reduced blood glucose (by 25%, P < 0.05) when compared to STZ rats. The drug did not affect levels of C-peptide, an indicator of insulin secretion, suggesting altered tissue glucose utilization. Crizotinib had no impact on cardiac RTKs. However, an mRNA downregulation of insulin-dependent glucose transporter Glut4 in the hearts of STZ rats was attenuated after crizotinib treatment. Moreover, crizotinib normalized Ppard and reduced Pparg mRNA expression in diabetic hearts. Crizotinib decreased blood glucose independently of insulin and glucagon. This could be related to changes in regulators of cardiac metabolism such as GLUT4 and PPARs.

Molecular mechanisms of arrhythmogenic cardiomyopathy

Arrhythmogenic cardiomyopathy is a genetic disorder characterized by the risk of life-threatening arrhythmias, myocardial dysfunction and fibrofatty replacement of myocardial tissue. Mutations in genes that encode components of desmosomes, the adhesive junctions that connect cardiomyocytes, are the predominant cause of arrhythmogenic cardiomyopathy and can be identified in about half of patients with the condition. However, the molecular mechanisms leading to myocardial destruction, remodelling and arrhythmic predisposition remain poorly understood. Through the development of animal, induced pluripotent stem cell and other models of disease, advances in our understanding of the pathogenic mechanisms of arrhythmogenic cardiomyopathy over the past decade have brought several signalling pathways into focus. These pathways include canonical and non-canonical WNT signalling, the Hippo-Yes-associated protein (YAP) pathway and transforming growth factor-β signalling. These studies have begun to identify potential therapeutic targets whose modulation has shown promise in preclinical models. In this Review, we summarize and discuss the reported molecular mechanisms underlying the pathogenesis of arrhythmogenic cardiomyopathy.

Pegfilgrastim and linagliptin potentiate chemoattraction of Ccr2 and Cd44 stem cells accompanied by alterations of cardiac Hgf, Igf-1 and Mcp-1 in daunorubicin cardiomyopathy

Objective

Daunorubicin (DAU) downregulates cytokines promoting stem cell migration and homing into the heart, reducing cardiac regeneration after anticancer chemotherapy. Pegfilgrastim (PFIL) protects from DAU-induced neutropenia but its cardioprotective potential remains unclear. We tested whether pegfilgrastim and a dipeptidyl peptidase-4 inhibitor linagliptin, potential enhancers of stem cells migration and homing, would improve DAU-cardiomyopathy.

Methods

DAU (7.5 mg/kg, i.v.) was administered to male Wistar rats to induce cardiotoxicity. Pegfilgrastim (100 µg/kg, s.c.) was administered 24h after DAU, and linagliptin was administered orally for 8 weeks (5 mg/kg/day, LINA). Cardiac damage markers (Nppa, Myh6, Myh7, Gp91phox), cytokines (Sdf-1alpha, Mcp-1, Vegf, Hgf, Igf-1), stem cell markers (Cxcr4, Ccr2, Cd34, Cd133, Cd44, Cd105) were determined by qRT-PCR.

Key findings

Decreased Myh6, elevated Myh7 Nppa, and Gp91phox were not ameliorated by PFIL + LINA. Downregulated expressions of cytokines (Vegf, Sdf-1alpha) and stem cells markers (Cxcr4, Cd34, Cd133, and Cd105) remained decreased after PFIL + LINA. DAU-induced upregulation of Mcp-1, Ccr2 and Cd44 was further potentiated by PFIL + LINA. PFIL + LINA normalised expression of Hgf and Igf-1.

Conclusions

Although PFIL + LINA failed in universal potentiation of stem cells migration and homing, the expression of stem cell markers Ccr2 and Cd44 in the heart potentially increased through the preservation of Hgf, Igf-1 and upregulation of Mcp-1.

PPARδ, a Potential Therapeutic Target for Heart Disease

The nuclear receptor peroxisome proliferator-activated receptor δ (PPARδ) can transcriptionally regulate target genes. PPARδ exerts essential regulatory functions in the heart, which requires constant energy supply. PPARδ plays a key role in energy metabolism, controlling not only fatty acid (FA) and glucose oxidation, but also redox homeostasis, mitochondrial biogenesis, inflammation, and cardiomyocyte proliferation. PPARδ signaling is impaired in the heart under various pathological conditions, such as pathological cardiac hypertrophy, myocardial ischemia/reperfusion, doxorubicin cardiotoxicity and diabetic cardiomyopathy. PPARδ deficiency in the heart leads to cardiac dysfunction, myocardial lipid accumulation, cardiac hypertrophy/remodeling and heart failure. This article provides an up-today overview of this research area and discusses the role of PPARδ in the heart in light of the complex mechanisms of its transcriptional regulation and its potential as a translatable therapeutic target for the treatment of cardiac disorders.

Gestational chronodisruption leads to persistent changes in the rat fetal and adult adrenal clock and function

KEY POINTS

Light at night is essential to a 24/7 society, but it has negative consequences on health. Basically, light at night induces an alteration of our biological clocks, known as chronodisruption, with effects even when this occurs during pregnancy. Here we explored the developmental impact of gestational chronodisruption (chronic photoperiod shift, CPS) on adult and fetal adrenal biorhythms and function. We found that gestational chronodisruption altered fetal and adult adrenal function, at the molecular, morphological and physiological levels. The differences between control and CPS offspring suggest desynchronization of the adrenal circadian clock and steroidogenic pathway, leading to abnormal stress responses and metabolic adaptation, potentially increasing the risk of developing chronic diseases.

ABSTRACT

Light at night is essential to a 24/7 society, but it has negative consequences on health. Basically, light at night induces an alteration of our biological clocks, known as chronodisruption, with effects even when this occurs during pregnancy. Indeed, an abnormal photoperiod during gestation alters fetal development, inducing long-term effects on the offspring. Accordingly, we carried out a longitudinal study in rats, exploring the impact of gestational chronodisruption on the adrenal biorhythms and function of the offspring. Adult rats (90 days old) gestated under chronic photoperiod shift (CPS) decrease the time spent in the open arm zone of an elevated plus maze to 62% and increase the rearing time to 170%. CPS adults maintained individual daily changes in corticosterone, but their acrophases were distributed from 12.00 h to 06.00 h. CPS offspring maintained clock gene expression and oscillation, nevertheless no daily rhythm was observed in genes involved in the regulation and synthesis of steroids. Consistent with adult adrenal gland being programmed during fetal life, blunted daily rhythms of corticosterone, core clock gene machinery, and steroidogenic genes were observed in CPS fetal adrenal glands. Comparisons of the global transcriptome of CPS versus control fetal adrenal gland revealed that 1078 genes were differentially expressed (641 down-regulated and 437 up-regulated). In silico analysis revealed significant changes in Lipid Metabolism, Small Molecule Biochemistry, Cellular Development and the Inflammatory Response pathway (z score: 48-20). Altogether, the present results demonstrate that gestational chronodisruption changed fetal and adult adrenal function. This could translate to long-term abnormal stress responses and metabolic adaptation, increasing the risk of developing chronic diseases.

Interplay between the renin-angiotensin system, the canonical WNT/β-catenin pathway and PPARγ in hypertension

PURPOSE OF REVIEW

Heterogeneous causes can determinate hypertension.

RECENT FINDINGS

The renin-angiotensin system (RAS) has a major role in the pathophysiology of blood pressure. Angiotensin II and aldosterone are overexpressed during hypertension and lead to hypertension development and its cardiovascular complications. In several tissues, the overactivation of the canonical WNT/β-catenin pathway leads to inactivation of peroxisome proliferator-activated receptor gamma (PPARγ), while PPARγ stimulation induces a decrease of the canonical WNT/β-catenin pathway. In hypertension, the WNT/β-catenin pathway is upregulated, whereas PPARγ is decreased. The WNT/β-catenin pathway and RAS regulate positively each other during hypertension, whereas PPARγ agonists can decrease the expression of both the WNT/β-catenin pathway and RAS. We focus this review on the hypothesis of an opposite interplay between PPARγ and both the canonical WNT/β-catenin pathway and RAS in regulating the molecular mechanism underlying hypertension. The interactions between PPARγ and the canonical WNT/β-catenin pathway through the regulation of the renin-angiotensin system in hypertension may be an interesting way to better understand the actions and the effects of PPARγ agonists as antihypertensive drugs.

Blockade of the renin-angiotensin-aldosterone system in patients with arrhythmogenic right ventricular dysplasia: A double-blind, multicenter, prospective, randomized, genotype-driven study (BRAVE study)

Arrhythmogenic right ventricular dysplasia (ARVD) is a rare cardiomyopathy characterized by the progressive replacement of cardiomyocytes by fatty and fibrous tissue in the right ventricle (RV). These infiltrations lead to cardiac electrical instability and ventricular arrhythmia. Current treatment for ARVD is empirical and essentially based on treatment of arrhythmia. Thus, there is no validated treatment that will prevent the deterioration of RV function in patients with ARVD. The aim of the BRAVE study is to evaluate the effect of ramipril, an angiotensin-converting enzyme inhibitor, on ventricular myocardial remodeling and arrhythmia burden in patients with ARVD. Despite the fact that myocardial fibrosis is one of the structural hallmarks of ARVD, no study has tested an antifibrotic drug in ARVD patients. The trial is a double-blind, parallel, multicenter, prospective, randomized, phase 4 drug study. Patients will be randomized into 2 groups, ramipril or placebo. The 120 patients (60 per group) will be enrolled by 26 centers in France. Patients will be followed up every 6 months for 3 years. The 2 co-primary endpoints are defined as the difference of telediastolic RV volume measured by magnetic resonance imaging between baseline and 3 years of follow-up, and the change in arrhythmia burden during the 3 years of follow-up. A decrease in RV and/or left ventricular deterioration and in arrhythmia burden are expected in ARVD patients treated with ramipril. This reduction will improve quality of life of patients and will reduce the number of hospitalizations and the risk of terminal heart failure.

Myocardial Expression of PPARγ and Exercise Capacity in Patients after Coronary Artery Bypass Surgery

Activation of PPARs may be involved in the development of heart failure (HF). We evaluated the relationship between expression of PPARγ in the myocardium during coronary artery bypass grafting (CABG) and exercise tolerance initially and during follow-up. 6-minute walking test was performed before CABG, after 1, 12, 24 months. Patients were divided into two groups (HF and non-HF) based on left ventricular ejection fraction and plasma proBNP level. After CABG, 67% of patients developed HF. The mean distance 1 month after CABG in HF was 397 ± 85 m versus 420 ± 93 m in non-HF. PPARγ mRNA expression was similar in both HF and non-HF groups. 6MWT distance 1 month after CABG was inversely correlated with PPARγ level only in HF group. Higher PPARγ expression was related to smaller LVEF change between 1 month and 1 year (R = 0.18, p < 0.05), especially in patients with HF. Higher initial levels of IL-6 in HF patients were correlated with longer distance in 6MWT one month after surgery and lower PPARγ expression. PPARγ expression is not related to LVEF before CABG and higher PPARγ expression in the myocardium of patients who are developing HF following CABG may have some protecting effect.

Ginsenoside Rh2 Improves Cardiac Fibrosis via PPARδ-STAT3 Signaling in Type 1-Like Diabetic Rats

Ginsenoside Rh2 (Rh2) is an active principal ingredient contained in ginseng (Panax ginseng Meyer), a medicinal herb used to enhance health worldwide. The present study is designed to investigate the effect of Rh2 on myocardial fibrosis in diabetic rats. In a streptozotocin-induced model of type-1 diabetic rats (STZ-diabetic rats), the increased fasting blood glucose levels and heart weight/body weight (HW/BW) ratio were substantially alleviated by Rh2. Moreover, Rh2 improved cardiac performance in STZ-diabetic rats. Histological results from Masson staining showed that Rh2 attenuated cardiac fibrosis in STZ-diabetic rats. The effects of Rh2 were reversed by GSK0660 at a dose sufficient to inhibit peroxisome proliferator-activated receptor δ (PPARδ) in STZ-diabetic rats. The role of PPARδ was subsequently investigated in vitro. Rh2 restored the decreased PPARδ expression level in high glucose-cultured cardiomyocytes. Moreover, increased protein levels of fibrotic signals, including signal transducer and activator of transcription 3 (STAT3), connective tissue growth factor (CCN2) and fibronectin, were reduced by Rh2 in high glucose-cultured cardiomyocytes. These effects of Rh2 were reversed by GSK0660 or siRNA specific for PPARδ Taken together, PPARδ activation may inhibit STAT3 activation to reduce CCN2 and fibronectin expression in diabetic rats with cardiac fibrosis. Moreover, Rh2 improves cardiac function and fibrosis by increasing PPARδ signaling. Therefore, Rh2 is suitable to develop as an alternative remedy for cardiac fibrosis.