Cardiomyocyte apoptosis is related to left ventricular dysfunction and remodelling in dilated cardiomyopathy, but is not affected by growth hormone treatment

NLRP3 inflammasome in cardiovascular diseases: Pathophysiological and pharmacological implications

Growing evidence points out the importance of nucleotide-binding oligomerization domain leucine-rich repeat and pyrin domain-containing protein 3 (NLRP3) inflammasome in the pathogenesis of cardiovascular diseases (CVDs), including hypertension, myocardial infarct (MI), ischemia, cardiomyopathies (CMs), heart failure (HF), and atherosclerosis. In this regard, intensive research efforts both in humans and in animal models of CVDs are being focused on the characterization of the pathophysiological role of NLRP3 inflammasome signaling in CVDs. In addition, clinical and preclinical evidence is coming to light that the pharmacological blockade of NLRP3 pathways with drugs, including novel chemical entities as well as drugs currently employed in the clinical practice, biologics and phytochemicals, could represent a suitable therapeutic approach for prevention and management of CVDs. On these bases, the present review article provides a comprehensive overview of clinical and preclinical studies about the role of NLRP3 inflammasome in the pathophysiology of CVDs, including hypertension, MI, ischemic injury, CMs, HF and atherosclerosis. In addition, particular attention has been focused on current evidence on the effects of drugs, biologics, and phytochemicals, targeting different steps of inflammasome signaling, in CVDs.

NLRP3 inflammasome-mediated pyroptosis contributes to the pathogenesis of non-ischemic dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is one of the most common causes of heart failure, and the underlying mechanism remains largely elusive. Here we investigated whether NLRP3 inflammasome-mediated pyroptosis contributes to non-ischemic DCM and dissected the underlying mechanism. We found that hyper activated NLRP3 inflammasome with pyroptotic cell death of cardiomyocytes were presented in the myocardial tissues of DCM patients, which were negatively correlated with cardiac function. Doxorubicin (Dox)-induced DCM characterization disclosed that NLRP3 inflammasome activation and pyroptosis occurred in Dox-treated heart tissues, but were very marginal in either NLRP3^-/- or caspase-1^-/- mice. Mechanistically, Dox enhanced expressions of NOX1 and NOX4 and induced mitochondrial fission through dynamin-related protein 1 (Drp1) activation, leading to NLRP3 inflammasome-mediated pyroptosis in cardiomyocytes via caspase-1-dependent manner. Conversely, both inhibitions of NOX1 and NOX4 and Drp1 suppressed Dox-induced NLPR3 inflammasome activation and pyroptosis. The alterations of NOX1 and NOX4 expression, Drp1 phosphorylation and mitochondrial fission were validated in DCM patients and mice. Importantly, Dox-induced Drp1-mediated mitochondrial fission and the consequent NLRP3 inflammasome activation and pyroptosis were reversed by NOX1 and NOX4 inhibition in mice. This study demonstrates for the first time that cardiomyocyte pyroptosis triggered by NLRP3 inflammasome activation via caspase-1 causally contributes to myocardial dysfunction progression and DCM pathogenesis.

Identification of key genes and pathways affected in epicardial adipose tissue from patients with coronary artery disease by integrated bioinformatics analysis

Background

Coronary artery disease (CAD) is a common disease with high cost and mortality. Here, we studied the differentially expressed genes (DEGs) between epicardial adipose tissue (EAT) and subcutaneous adipose tissue (SAT) from patients with CAD to explore the possible pathways and mechanisms through which EAT participates in the CAD pathological process.

Methods

Microarray data for EAT and SAT were obtained from the Gene Expression Omnibus database, including three separate expression datasets: GSE24425, GSE64554 and GSE120774. The DEGs between EAT samples and SAT control samples were screened out using the limma package in the R language. Next, we conducted bioinformatic analysis of gene ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways to discover the enriched gene sets and pathways associated with DEGs. Simultaneously, gene set enrichment analysis was carried out to discover enriched gene functions and pathways from all expression data rather than DEGs. The PPI network was constructed to reveal the possible protein interactions consistent with CAD. Mcode and Cytohubba in Cytoscape revealed the possible key CAD genes. In the next step, the corresponding predicted microRNAs (miRNAs) were analysed using miRNA Data Integration Portal. RT-PCR was used to validate the bioinformatic results.

Results

The three datasets had a total of 89 DEGs (FC log2 > 1 and P value < 0.05). By comparing EAT and SAT, ten common key genes (HOXA5, HOXB5, HOXC6, HOXC8, HOXB7, COL1A1, CCND1, CCL2, HP and TWIST1) were identified. In enrichment analysis, pro-inflammatory and immunological genes and pathways were up-regulated. This could help elucidate the molecular expression mechanism underlying the involvement of EAT in CAD development. Several miRNAs were predicted to regulate these DEGs. In particular, hsa-miR-196a-5p and hsa-miR-196b-5p may be more reliably associated with CAD. Finally, RT-PCR validated the significant difference of OXA5, HOXC6, HOXC8, HOXB7, COL1A1, CCL2 between EAT and SAT (P value < 0.05).

Conclusions

Between EAT and SAT in CAD patients, a total of 89 DEGs, and 10 key genes, including HOXA5, HOXB5, HOXC6, HOXC8, HOXB7, COL1A1, CCND1, CCL2, HP and TWIST1, and miRNAs hsa-miR-196a-5p and hsa-miR-196b-5p were predicted to play essential roles in CAD pathogenesis. Pro-inflammatory and immunological pathways could act as key EAT regulators by participating in the CAD pathological process.

Sulfur dioxide induces apoptosis via reactive oxygen species generation in rat cardiomyocytes

Epidemiological evidence suggests that the incidence and mortality of cardiovascular diseases are closely related to sulfur dioxide (SO₂). In the present study, H9C2 cells were incubated with 100 μM NaHSO₃ with or without pretreatment of an antioxidant, N-acetyl-L-cysteine (NAC). The changes of apoptosis rate, mitochondrial membrane potential (MMP), ATP content, caspase-3 activity, and reactive oxygen species (ROS) were detected. Rats were inhaled 7 mg/m³ SO₂ and/or intraperitoneal injected with 50 mg/kg (bw) of NAC for 30 days. RT-PCR and Western blot were used to detect the mRNA and protein levels of apoptosis-related genes. We found that the apoptosis of H9C2 cells was induced by NaHSO₃, which decreased the content of MMP and ATP, and induced the expression of caspase-3. NAC can inhibit the apoptosis induced by NaHSO₃ treatment. SO₂ and NaHSO₃ decreased the expression of Bcl-2 and the ratio of Bcl-2/Bax, increased the expression of Bax and P53 accumulation and phosphorylation, and activated caspase-9 and caspase-3. Whereas NAC can reduce the changes of apoptosis-related proteins in rat heart. Our results suggest that SO₂ induces ROS-mediated P53 and caspase-dependent mitochondrial signaling pathways in H9C2 cells and rat hearts. Antioxidant therapy can reduce the adverse reactions of SO₂ and lead to a decline in the cardiovascular disease induced by SO₂.

Is galectin-3 a promoter of ventricular dysfunction?

Heart failure is nowadays a common condition associated with high mortality and increased healthcare-related costs. Over the years, the research on heart failure management has been extensive in order to better diagnose and treat the condition. Since the progression of left ventricular dysfunction is a consequence of myocardial inflammation, apopotosis, and fibrosis leading to myocardium remodelling, several molecules that are involved in the inflammation pathways have been explored as possible biomarkers for the condition. The study of biomarkers and their key roles in inflammation could allow early identification of patients with heart failure, improve prognostic assessment, and provide a target for future therapies. Among currently studied biomarkers, extensive research has been conducted on galectin-3, a galactoside-binding lectin, which is synthetised and secreted when cardiomyocytes and fibroblasts are submitted to mechanical stress. Accordingly, it has been hypothesised that galectin-3 could be a promoter of left ventricular dysfunction. Galectin-3 has been shown to mediate inflammation by several different pathways which are further detailed in the current review. Also, we aimed to provide a comprehensive overview of existing evidence on the utility of galectin-3 in clinical settings associated with heart failure.

Role of MicroRNA-93 I in Pathogenesis of Left Ventricular Remodeling via Targeting Cyclin-D1

Background

The objective of this study was to identify the pathway responsible for ventricular remodeling.

Material/Methods

We collected remodeling myocardium tissue (n=18) and control myocardium tissue (n=22), and detected the expression of 4 miRNAs in these 2 groups using real-time PCR. We then searched the miRNA database online to find the candidate genes of miR-93. Real-time PCR and Western blot analysis were used to confirm the regulatory relationship.

Results

We found that only miR-93 was decreased in remodeling myocardium tissue, and validated CCND1 to be the direct target gene of miR-93, with the “seed sequence” located within the 3′-UTR of the target gene via luciferase reporter assay system. Furthermore, we established the negative regulatory relationship between miR-93 and CCND1 by determining the relative luciferase activity of cells transfected with wild-type or mutant 3′-UTR of CCND1. We also found that The CCND1 protein and mRNA expression level of HL-1 cells treated with 50 nM miR-93 mimics were apparently lower than the scramble control, and those of the cells treated with 100 nM miR-93 mimics and CCND1 siRNA (100 nM) were even lower than those in the 50 nM treatment group. Meanwhile, cells transfected with miR-93 mimics (50 nM) showed evidently downregulated viability when compared with the scramble controls, while cells transfected with (100 nM) and CCND1 siRNA (100nM) showed even lower viability.

Conclusions

We showed that CCND1 is a direct target of miR-93, and the dysregulation of the miR-93/CCND1 signaling pathway is responsible for the development of ventricular remodeling.

Doxorubicin-induced chronic dilated cardiomyopathy-the apoptosis hypothesis revisited

The chemotherapeutic agent doxorubicin (DOX) has significantly increased survival rates of pediatric and adult cancer patients. However, 10% of pediatric cancer survivors will 10-20 years later develop severe dilated cardiomyopathy (DCM), whereby the exact molecular mechanisms of disease progression after this long latency time remain puzzling. We here revisit the hypothesis that elevated apoptosis signaling or its increased likelihood after DOX exposure can lead to an impairment of cardiac function and cause a cardiac dilation. Based on recent literature evidence, we first argue why a dilated phenotype can occur when little apoptosis is detected. We then review findings suggesting that mature cardiomyocytes are protected against DOX-induced apoptosis downstream, but not upstream of mitochondrial outer membrane permeabilisation (MOMP). This lack of MOMP induction is proposed to alter the metabolic phenotype, induce hypertrophic remodeling, and lead to functional cardiac impairment even in the absence of cardiomyocyte apoptosis. We discuss findings that DOX exposure can lead to increased sensitivity to further cardiomyocyte apoptosis, which may cause a gradual loss in cardiomyocytes over time and a compensatory hypertrophic remodeling after treatment, potentially explaining the long lag time in disease onset. We finally note similarities between DOX-exposed cardiomyocytes and apoptosis-primed cancer cells and propose computational system biology as a tool to predict patient individual DOX doses. In conclusion, combining recent findings in rodent hearts and cardiomyocytes exposed to DOX with insights from apoptosis signal transduction allowed us to obtain a molecularly deeper insight in this delayed and still enigmatic pathology of DCM.

Ibutilide protects against cardiomyocytes injury via inhibiting endoplasmic reticulum and mitochondrial stress pathways

Atrial fibrillation (AF) is a complex disease with multiple inter-relating causes culminating in rapid atrial activation and atrial structural remodeling. The contribution of endoplasmic reticulum and mitochondria stress to AF has been highlighted. As the class III antiarrhythmic agent, ibutilide are widely used to AF. This study was designed to explore whether ibutilide could treat AF by inhibiting endoplasmic reticulum stress pathways and mitochondria stress. The neonatal rat cardiomyocytes were isolated and exposed to H₂O₂, ibutilide was add to the culture medium 12 h. Then the cell viability, oxidative stress levels and apoptotic rate were analyzed. In addition, endoplasmic reticulum stress related protein (GRP78, GRP94, CHOP), mitochondria-dependent protein (Bax, Bcl-2) and caspase-3/9/12 were identified by real-time PCR and western blot analysis. In our results, remarkable decreased cell viability and oxidative stress levels were detected in cardiomyocytes after treating with H₂O₂. The apoptotic rate and the expression of proteins involved in mitochondrial stress and endoplasmic reticulum stress pathways increased. While ibutilide significantly inhibited these changes. These data suggested that ibutilide serves a protective role against H₂O₂-induced apoptosis of neonatal rat cardiomyocytes, and the mechanism is related to suppression of mitochondrial stress and endoplasmic reticulum stress.

Induction of Ankrd1 in Dilated Cardiomyopathy Correlates with the Heart Failure Progression

Progression of idiopathic dilated cardiomyopathy (IDCM) is marked with extensive left ventricular remodeling whose clinical manifestations and molecular basis are poorly understood. We aimed to evaluate the clinical potential of titin ligands in monitoring progression of cardiac remodeling associated with end-stage IDCM. Expression patterns of 8 mechanoptotic machinery-associated titin ligands (ANKRD1, ANKRD2, TRIM63, TRIM55, NBR1, MLP, FHL2, and TCAP) were quantitated in endomyocardial biopsies from 25 patients with advanced IDCM. When comparing NYHA disease stages, elevated ANKRD1 expression levels marked transition from NYHA < IV to NYHA IV. ANKRD1 expression levels closely correlated with systolic strain depression and short E wave deceleration time, as determined by echocardiography. On molecular level, myocardial ANKRD1 and serum adiponectin correlated with low BAX/BCL-2 ratios, indicative of antiapoptotic tissue propensity observed during the worsening of heart failure. ANKRD1 is a potential marker for cardiac remodeling and disease progression in IDCM. ANKRD1 expression correlated with reduced cardiac contractility and compliance. The association of ANKRD1 with antiapoptotic response suggests its role as myocyte survival factor during late stage heart disease, warranting further studies on ANKRD1 during end-stage heart failure.

Long term results and predictors of left ventricular function recovery after aortic valve replacement for chronic aortic regurgitation

OBJECTIVES

In most patients with aortic regurgitation (AR), aortic valve replacement (AVR) improves left ventricular (LV) function, but some patients will not have favorable remodeling. Our objectives were to review long term clinical results of AVR for AR and to examine what factors affect the normalization of LV function after AVR for chronic AR.

METHODS

Between 1989 and 2010, 177 patients underwent isolated AVR for chronic pure AR. The patients were divided into 2 groups based on indexed end-systolic LV diameter (iESD): Group L (iESD) ≥25 mm/m(2)) (130 patients) and Group S (iESD <25 mm/m(2)) (47 patients).

RESULTS

There was no significant difference between groups in late mortality, freedom from cardiac-related death and rehospitalization for heart failure at late follow up after operation. At postoperative follow-up, 16% of patients had not recovered normal LV systolic function. By means of multivariate analysis, iESD and cardiac index (CI) were independent predictors of recovery of LV function and iESD >26.7 mm/m(2) and CI <2.71 l/min/m(2) were the best cut-off values.

CONCLUSIONS

Early and late surgical results of AVR for chronic AR were good, but for the preservation of postoperative normal LV function, AVR for AR patients should be performed before iESD reaches 26.7 mm/m(2).

Prolactin protects cardiomyocytes against intermittent hypoxia-induced cell damage by the modulation of signaling pathways related to cardiac hypertrophy and proliferation

OBJECTIVES

Prolactin (PRL) is a multifunctional hormone that influences multiple physiological processes. It has been shown to have a protective effect on the cardiovascular system; however, the mechanisms of this effect are poorly understood. The purpose of the study was to elucidate the role of PRL in intermittent hypoxia (IH)-induced apoptosis in the cardiovascular system.

METHOD AND RESULTS

We established a hyperprolactinemic rat model by implanting two anterior pituitary (AP) glands into the renal capsule of male Sprague-Dawley rats. The rats were kept under normoxic conditions for 4weeks after implantation in order to reach the expression plateau of PRL in the plasma, and then treated with IH for 7 or 14days. Their hearts were then removed for histological and protein expression analyses. Cerebral cortex (CX)-grafted control rats challenged with IH displayed unique phenotypes such as a thicker heart wall, an abnormal myocardial architecture and an increased interstitial space of the left ventricle. They exhibited reduced expressions of p-JAK2, p-STAT5, cell cycle-dependent proteins (cyclin D1, cyclin E and cyclin A), IGF-IRα, PI3Kα, p-AKT and p-ERK1/2 in cardiomyocytes at 7days.

CONCLUSIONS

Our comprehensive analysis suggested that high plasma PRL can protect rat cardiomyocytes against IH through (1) the p-JAK2 and p-STAT5 pathways for transient cell proliferation, (2) the PI3Kα/AKT and MAPK survival pathways through IGF-I, and (3) the downregulation of IGF-II and ERK5, which inhibit cell hypertrophy.

Cardiomyocyte apoptosis contributes to pathogenesis of cirrhotic cardiomyopathy in bile duct-ligated mice

Cirrhotic cardiomyopathy is defined as systolic and diastolic dysfunctions, electrophysiological changes and macroscopic structural changes. However, the underlying mechanisms of this syndrome remain unclear. A possible role of myocardial apoptosis in the pathogenesis has not been previously examined. We hypothesized that dysregulation of apoptotic signalling participates in cardiac dysfunction in the cirrhotic heart. Therefore, we evaluated apoptotic pathways in the hearts of mice with chronic BDL (bile duct ligation). A cirrhotic cardiomyopathy model was induced by BDL in mice. Left ventricular geometry and volumes were evaluated by MRI. Intrinsic and extrinsic apoptotic pathways were evaluated by immunohistochemical staining and Western blot analysis. Fas-mediated apoptosis was inhibited by in vivo administration of an anti-FasL (Fas ligand) monoclonal antibody, and subsequently cardiac contractility was measured in isolated cardiomyocytes. BDL-mice showed significantly more PARP [poly(ADP-ribose) polymerase] staining than sham controls (18.2±11.4 compared with 6.7±5.3; P<0.05). Fas protein expression and PARP cleavage were activated, whereas FLIP (Fas-associated death domain-like interleukin 1β-converting enzyme-inhibitory protein) was decreased compared with sham controls. The Bcl-2/Bax ratio was increased in BDL-mice compared with sham controls. Anti-FasL monoclonal antibody injection in BDL-mice improved systolic and diastolic dysfunctions in cardiomyocytes, but had no effect in sham controls. A net pro-apoptotic balance exists in BDL hearts, mainly mediated by activation of the extrinsic pathway, and abrogation of apoptosis improved contractility. These results suggest that apoptosis contributes to depressed cardiac contractility in a murine model of cirrhotic cardiomyopathy.

Mechano-signaling in heart failure

Mechanosensation and mechanotransduction are fundamental aspects of biology, but the link between physical stimuli and biological responses remains not well understood. The perception of mechanical stimuli, their conversion into biochemical signals, and the transmission of these signals are particularly important for dynamic organs such as the heart. Various concepts have been introduced to explain mechanosensation at the molecular level, including effects on signalosomes, tensegrity, or direct activation (or inactivation) of enzymes. Striated muscles, including cardiac myocytes, differ from other cells in that they contain sarcomeres which are essential for the generation of forces and which play additional roles in mechanosensation. The majority of cardiomyopathy causing candidate genes encode structural proteins among which titin probably is the most important one. Due to its elastic elements, titin is a length sensor and also plays a role as a tension sensor (i.e., stress sensation). The recent discovery of titin mutations being a major cause of dilated cardiomyopathy (DCM) also underpins the importance of mechanosensation and mechanotransduction in the pathogenesis of heart failure. Here, we focus on sarcomere-related mechanisms, discuss recent findings, and provide a link to cardiomyopathy and associated heart failure.

Protective effects of hydrogen sulfide against chronic alcohol intake-induced left ventricular remodeling in rats

PURPOSE

To investigate the protective effects of hydrogen sulfide (H(2)S) against chronic alcohol intake-induced left ventricular remodeling and explore the potential mechanisms involved.

METHODS

Rats were randomly divided into 4 groups: alcohol group, NaHS group, alcohol + NaHS group, and control group. The echocardiographic and morphometric studies were performed to assess left ventricular remodeling. Oxidative stress was evaluated by detecting MDA, GSH-Px, Tot-SOD, CuZn-SOD and Mn-SOD in the supernatant. Cardiomyocyte apoptotic rate was determined by flow cytometry with Annexin V/PI staining. Western blotting was conducted to detect the expression of Bcl-2 family of apoptosis regulator proteins.

RESULTS

The echocardiographic and morphometric data indicated that H(2)S has protective effects against chronic alcohol intake-induced left ventricular remodeling. Our findings showed a significant increase in MDA level and decreases in GSH-Px, Tot-SOD, CuZn-SOD and Mn-SOD activities in the alcohol group compared to the control group, while in the alcohol + NaHS group, a significant decrease in MDA level and increases in GSH-Px, Tot-SOD, CuZn-SOD and Mn-SOD activities were found compared to the alcohol group. The apoptotic rate in the alcohol group was significantly higher than in the control group, whereas apoptotic rate in the alcohol + NaHS group was significantly lower than in the alcohol group. In addition, Bcl-2 and Bcl-xL expression was upregulated and Bax expression was downregulated in the alcohol + NaHS group compared to the alcohol group.

CONCLUSIONS

Our study demonstrates that H(2)S protects against chronic alcohol intake-induced left ventricular remodeling via attenuating oxidative stress and apoptosis.

Pediatric cardiomyopathies: causes, epidemiology, clinical course, preventive strategies and therapies

Pediatric cardiomyopathies, which are rare but serious disorders of the muscles of the heart, affect at least one in every 100,000 children in the USA. Approximately 40% of children with symptomatic cardiomyopathy undergo heart transplantation or die from cardiac complications within 2 years. However, a significant number of children suffering from cardiomyopathy are surviving into adulthood, making it an important chronic illness for both pediatric and adult clinicians to understand. The natural history, risk factors, prevalence and incidence of this pediatric condition were not fully understood before the 1990s. Questions regarding optimal diagnostic, prognostic and treatment methods remain. Children require long-term follow-up into adulthood in order to identify the factors associated with best clinical practice including diagnostic approaches, as well as optimal treatment approaches. In this article, we comprehensively review current research on various presentations of this disease, along with current knowledge about their causes, treatments and clinical outcomes.

On mechanosensation, acto/myosin interaction, and hypertrophy

Current concepts of mechanosensation are general and applicable to almost every cell type. However, striated muscle cells are distinguished by their ability to generate strong forces via actin/myosin interaction, and this process is fine-tuned for optimum contractility. This aspect, unique for actively contracting cells, may be defined as "sensing of the magnitude and dynamics of contractility," as opposed to the well-known concepts of the "perception of extracellular mechanical stimuli." The acto/myosin interaction, by producing changes in ATP, ADP, Pi, and force on a millisecond timescale, may be regarded as a novel and previously unappreciated mechanosensory mechanism. In addition, sarcomeric mechanosensory structures, such as the Z-disc, are directly linked to autophagy, survival, and cell death-related pathways. One emerging example is telethonin and its ability to interfere with p53 metabolism and hence apoptosis (mechanoptosis). In this article, we introduce contractility per se as an important mechanosensory mechanism, and we differentiate extracellular from intracellular mechanosensory effects.

Trimetazidine protects against smoking-induced left ventricular remodeling via attenuating oxidative stress, apoptosis, and inflammation

Trimetazidine, a piperazine derivative used as an anti-anginal agent, improves myocardial glucose utilization through inhibition of fatty acid metabolism. The present study was designed to investigate whether trimetazidine has the protective effects against smoking-induced left ventricular remodeling in rats. In this study, Wistar rats were randomly divided into 3 groups: smoking group (exposed to cigarette smoke), trimetazidine group (exposed to cigarette smoke and treated with trimetazidine), and control group. The echocardiographic and morphometric data indicated that trimetazidine has protective effects against smoking-induced left ventricular remodeling. Oxidative stress was evaluated by detecting malondialdehyde, superoxide dismutase, and glutathione peroxidase in the supernatant of left ventricular tissue. Cardiomyocyte apoptotic rate was determined by flow cytometry with Annexin V/PI staining. Gene expression and serum levels of inflammatory markers, including interleukin-1β, interleukin-6, and tumor necrosis factor-α, were deteced by quantitative real-time PCR and enzyme-linked immunosorbent assay. Our results suggested that trimetazidine could significantly reduce smoking-induced oxidative stress, apoptosis, and inflammation. In conclusion, our study demonstrates that trimetazidine protects against smoking-induced left ventricular remodeling via attenuating oxidative stress, apoptosis, and inflammation.

Protective effects of valsartan against cigarette smoke-induced left ventricular systolic dysfunction in rats

OBJECTIVES

To investigate the protective effects of valsartan against smoking-induced left ventricular dysfunction and explore the potential mechanisms involved.

METHODS

Rats were randomly divided into 3 groups: smoking group (exposed to cigarette smoke), valsartan group (exposed to cigarette smoke and treated orally with valsartan), and control group. Transthoracic echocardiography was performed to evaluate left ventricular systolic and diastolic function. Oxidative stress was evaluated by detecting malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the supernatant of left ventricular tissue. Cardiomyocyte apoptotic rate was determined by flow cytometry with Annexin V/PI staining. Serum levels of high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), tumor necrosis factor-a (TNF-α), and monocyte chemotactic protein-1 (MCP-1) were detected to reflect the extent of systemic inflammation.

RESULTS

The echocardiographic data indicated that valsartan has protective effects against cigarette smoke-induced left ventricular systolic dysfunction (LVSD). Our findings showed a significant decrease in MDA level and increases in SOD and GSH-Px activities in the valsartan group compared to the smoking group. The apoptotic rate in the valsartan group was significantly lower than in the smoking group. The concentrations of hs-CRP, IL-6, TNF-α and MCP-1 in the valsartan group were significantly lower than in the smoking group.

CONCLUSIONS

Our study demonstrates that valsartan has protective effects against smoking-induced LVSD by attenuating oxidative stress, apoptosis, and inflammation.

Growth hormone resistance in severe heart failure resolves after cardiac transplantation

AIMS

Severe heart failure (HF) is associated with cachexia; this is often reversed post cardiac transplantation (HTx) with frequent development of obesity. Growth hormone (GH) resistance is common in HF and may contribute to cachexia. Whether GH resistance resolves post HTx is unknown. We aimed to confirm that HF is associated with GH resistance and to test the hypothesis that GH resistance resolves post HTx.

METHODS AND RESULTS

We measured GH, insulin-like growth factor-1 (IGF-1), and body composition in 10 HF patients awaiting HTx, in 18 patients 11 +/- 8 months post HTx, and seven controls. Body mass index was 23.5 +/- 3.2 in HF patients and 29.3 +/- 5.7 post HTx. HTx patients had gained 14 +/- 8 kg since HTx. GH was elevated in HF (control: 0.21 +/- 0.25; HF: 1.13 +/- 1.19; HTx: 0.11 +/- 0.13 ng/mL; P < 0.007), while IGF-1 was higher in HTx (control: 114 +/- 57; HF: 94 +/- 52; HTx: 190 +/- 106 ng/mL; P < 0.02). HTx had higher total body and abdominal fat %.

CONCLUSION

GH resistance is present in severe HF and resolves post HTx. These findings should be confirmed through larger trials.