Advances in cardiovascular research have identified oxidative stress as an important pathophysiological pathway in the development and progression of heart failure. Oxidative stress is defined as the ...imbalance between the production of reactive oxygen species (ROS) and the endogenous antioxidant defence system. Under physiological conditions, small quantities of ROS are produced intracellularly, which function in cell signalling, and can be readily reduced by the antioxidant defence system. However, under pathophysiological conditions, the production of ROS exceeds the buffering capacity of the antioxidant defence system, resulting in cell damage and death. Over the last decades several studies have tried to target oxidative stress with the aim to improve outcome in patients with heart failure, with very limited success. The reasons as to why these studies failed to demonstrate any beneficial effects remain unclear. However, one plausible explanation might be that currently employed strategies, which target oxidative stress by exogenous inhibition of ROS production or supplementation of exogenous antioxidants, are not effective enough, while bolstering the endogenous antioxidant capacity might be a far more potent avenue for therapeutic intervention. In this review, we provide an overview of oxidative stress in the pathophysiology of heart failure and the strategies utilized to date to target this pathway. We provide novel insights into modulation of endogenous antioxidants, which may lead to novel therapeutic strategies to improve outcome in patients with heart failure.
Objectives This study sought to determine the prognostic value of B-type natriuretic peptide (BNP) in patients with heart failure with preserved ejection fraction (HFPEF), in comparison to data in HF ...patients with reduced left ventricular (LV) EF (≤40%). Background Management of patients with HFPEF is difficult. BNP is a useful biomarker in patients with reduced LVEF, but data in HFPEF are scarce. Methods In this study, 615 patients with mild to moderate HF (mean age 70 years, LVEF 33%) were followed for 18 months. BNP concentrations were measured at baseline and were related to the primary outcome, that is, a composite of all-cause mortality and HF hospitalization, and to mortality alone. The population was divided in quintiles, according to LVEF, and patients with reduced LVEF were compared with those with HFPEF. Results There were 257 patients (42%) who had a primary endpoint and 171 (28%) who died. BNP levels were significantly higher in patients with reduced LVEF than in those with HFPEF (p < 0.001). BNP was a strong predictor of outcome, but LVEF was not. Importantly, if similar levels of BNP were compared across the whole spectrum of LVEF, and for different cutoff levels of LVEF, the associated risk of adverse outcome was similar in HFPEF patients as in those with reduced LVEF. Conclusions BNP levels are lower in patients with HFPEF than in patients with HF with reduced LVEF, but for a given BNP level, the prognosis in patients with HFPEF is as poor as in those with reduced LVEF.
Galectins are a family of soluble β-galactoside-binding lectins that play many important regulatory roles in inflammation, immunity, and cancer. Recently, a role for galectin-3 in the pathophysiology ...of heart failure (HF) has been suggested. Numerous studies have demonstrated the up-regulation of galectin-3 in hypertrophied hearts, its stimulatory effect on macrophage migration, fibroblast proliferation, and the development of fibrosis. The latter observation is particularly relevant as cardiac remodelling is an important determinant of the clinical outcome of HF and is linked to disease progression and poor prognosis. Because galectin-3 expression is maximal at peak fibrosis and virtually absent after recovery, routine measurement in patients with HF may prove valuable to identify those patients at highest risk for readmission or death, thus enabling physicians to tailor the level of care to individual patient needs. This review summarizes the most recent advances in galectin-3 research, with an emphasis on the role galectin-3 plays in the development and progression of HF.
Metformin is the first choice drug for the treatment of patients with diabetes, but its use is debated in patients with advanced cardiorenal disease. Epidemiological data suggest that metformin may ...reduce cardiac events, in patients both with and without heart failure. Experimental evidence suggests that metformin reduces cardiac ischemia-reperfusion injury. It is unknown whether metformin improves cardiac function (remodeling) in a long-term post-MI remodeling model. We therefore studied male, nondiabetic, Sprague-Dawley rats that were subjected to either myocardial infarction (MI) or sham operation. Animals were randomly allocated to treatment with normal water or metformin-containing water (250 mg·kg(-1)·day(-1)). At baseline, 6 wk, and 12 wk, metabolic parameters were analyzed and oral glucose tolerance tests (OGTT) were performed. Echocardiography and hemodynamic parameters were assessed 12 wk after MI. In the MI model, infarct size was significantly smaller after 12-wk metformin treatment (29.6 ± 3.2 vs. 38.0 ± 2.2%, P < 0.05). Moreover, metformin resulted in less left ventricular dilatation (6.0 ± 0.4 vs. 7.6 ± 0.6 mm, P < 0.05) and preservation of left ventricular ejection fraction (65.8 ± 3.7% vs. 48.6 ± 5.6%, P < 0.05) compared with MI control. The improved cardiac function was associated with decreased atrial natriuretic peptide mRNA levels in the metformin-treated group (50% reduction compared with MI, P < 0.05). Insulin resistance did not occur during cardiac remodeling (as indicated by normal OGTT) and fasting glucose levels and the pattern of the OGTT were not affected by metformin. Molecular analyses suggested that altered AMP kinase phosphorylation status and low insulin levels mediate the salutary effects of metformin. Altogether our results indicate that metformin may have potential to attenuate heart failure development after myocardial infarction, in the absence of diabetes and independent of systemic glucose levels.
Atrial fibrillation (AF) is often preceded by underlying cardiac diseases causing ventricular pressure overload.
It was our aim to investigate the progression of atrial remodeling in a small animal ...model of ventricular pressure overload and its association with induction of AF.
Male mice were subjected to transverse aortic constriction (TAC) or sham operation. After four or eight weeks, echocardiographic measurements and hemodynamic measurements were made and AF induction was tested. The hearts were either fixed in formalin or ventricles and atria were separated, weighed and snap-frozen for RNA analysis.
Four weeks of pressure overload induced ventricular hypertrophy and minor changes in the atria. After eight weeks a significant reduction in left ventricular function occurred, associated with significant atrial remodeling including increased atrial weight, a trend towards an increased left atrial cell diameter, atrial dilatation and increased expression of markers of hypertrophy and inflammation. Histologically, no fibrosis was found in the left atrium. But atrial gene expression related to fibrosis was increased. Minor changes related to electrical remodeling were observed. AF inducibility was not different between the groups. Left ventricular end diastolic pressures were increased and correlated with the severity of atrial remodeling but not with AF induction.
Permanent ventricular pressure overload by TAC induced atrial remodeling, including hypertrophy, dilatation and inflammation. The extent of atrial remodeling was directly related to LVEDP and not duration of TAC per se.
Differences in clinical characteristics and outcome of patients with established heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF) are ...well established. Data on epidemiology and prediction of new onset HFpEF, compared with HFrEF, have not been described.
In 8592 subjects of the Prevention of Renal and Vascular End-stage Disease (PREVEND), a community-based, middle-aged cohort study, we performed cause-specific hazard analyses to study the predictive value of risk factors and established cardiovascular biomarkers on new onset HFrEF vs. HFpEF (left ventricular ejection fraction ≤ 40 and ≥ 50%, respectively). A P-value for competing risk (Pcr) <0.10 between HFrEF and HFpEF was considered statistically significant. All potential new onset heart failure cases were reviewed and adjudicated to HFrEF or HFpEF by an independent committee. During a median follow-up of 11.5 years, 374 (4.4%) subjects were diagnosed with heart failure, of which 125 (34%) with HFpEF and 241 (66%) with HFrEF. The average time to diagnosis of new onset HFrEF was 6.6 ± 3.6 years; it was 8.3 ± 3.3 years for HFpEF (P < 0.001). Male gender was associated with new onset HFrEF, whereas female gender with new onset HFpEF (Pcr < 0.001). Higher age and increased N-terminal pro-B-type natriuretic peptide (NT-proBNP) increased the risk for both HFpEF and HFrEF, although for age this was stronger for HFpEF (Pcr = 0.018), whereas NT-proBNP was stronger associated with risk for HFrEF (Pcr = 0.083). Current smokers, increased highly sensitive troponin T, and previous myocardial infarction conferred a significantly increased risk for HFrEF, but not for HFpEF (Pcr = 0.093, 0.091, and 0.061, respectively). Conversely, a history of atrial fibrillation, increased urinary albumin excretion (UAE), and cystatin C were significantly more associated with the risk for HFpEF, but not for HFrEF (Pcr < 0.001, 0.061, and 0.033, respectively). The presence of obesity at baseline was associated with comparable prognostic information for both HFpEF and HFrEF.
Higher age, UAE, cystatin C, and history of atrial fibrillation are strong risk factors for new onset HFpEF. This underscores differential pathophysiological mechanisms for both subtypes of heart failure.
Aging is a biological process that affects most cells, organisms and species. Telomeres have been postulated as a universal biological clock that shortens in parallel with aging in cells. Telomeres ...are located at the end of the chromosomes and consist of an evolutionary conserved repetitive nucleotide sequence ranging in length from a few hundred base pairs in yeast till several kilo base pairs in vertebrates. Telomeres associate with shelterin proteins and form a complex protecting the chromosomal deoxyribonucleic acid (DNA) from recognition by the DNA damage-repair system. Due to the “end-replication problem” telomeres shorten with each mitotic cycle resulting in cumulative telomere attrition during aging. When telomeres reach a critical length the cell will not further undergo cell divisions and become senescent or otherwise dysfunctional. Telomere shortening has not only been linked to aging but also to several age associated diseases, including tumorigenesis, coronary artery disease, and heart failure. In the current review, we will discuss the role of telomere biology in relation to aging and aging associated diseases.
Endothelial cell senescence is an important contributor to vascular aging and is increased under diabetic conditions. Here we investigated whether the antidiabetic hormone glucagon-like peptide 1 ...(GLP-1) could prevent oxidative stress-induced cellular senescence in endothelial cells.
In Zucker diabetic fatty rats, a significant 2-fold higher level of vascular senescence was observed compared with control lean rats. Dipeptidyl-peptidase 4 (DPP-4) inhibition significantly increased GLP-1 levels in these animals and reduced senescence almost to lean animal levels. In vitro studies with human umbilical vein endothelial cells showed that GLP-1 had a direct protective effect on oxidative stress (H(2)O(2))-induced senescence and was able to attenuate oxidative stress-induced DNA damage and cellular senescence. The GLP-1 analogue exendin-4 provided similar results, whereas exendin fragment 9-39, a GLP-1 receptor antagonist, abolished this effect. Intracellular signaling by the phosphoinositide 3-kinase (PI3K)/Akt survival pathway did not appear to be involved. Further analysis revealed that GLP-1 activates the cAMP response element-binding (CREB) transcription factor in a cAMP/protein kinase A (PKA)-dependent manner, and inhibition of the cAMP/PKA pathway abolished the GLP-1 protective effect. Expression analysis revealed that GLP-1 can induce the oxidative defense genes HO-1 and NQO1.
Dipeptidyl-peptidase 4 inhibition protects against vascular senescence in a diabetic rat model. In vitro studies with human umbilical vein endothelial cells showed that reactive oxygen species-induced senescence was attenuated by GLP-1 in a receptor-dependent manner involving downstream PKA signaling and induction of antioxidant genes.
Important improvements have been made in treatment of diseases associated with atrial fibrillation (AF), such as hypertension, myocardial infarction, and heart failure. Incidence rates and risk ...factors may have changed with the aging of the population and changing lifestyles. Currently, the risk for AF is only partially explained, possibly because of differences between older cohorts and contemporary populations.
This study investigated the incidence of AF in a contemporary cohort in the Netherlands, together with comorbidities associated with AF and associations of AF with cardiovascular outcomes.
Incident AF was ascertained for hospital and study electrocardiograms in 8,265 participants of the PREVEND (Prevention of Renal and Vascular End-Stage Disease) study in Groningen, the Netherlands.
During 9.7 ± 2.3 years of follow-up, 265 participants developed AF, with a resulting overall AF incidence of 3.3 per 1,000 person-years. Advancing age, male sex, antihypertensive drug use, higher body mass index, previous myocardial infarction, and previous stroke were associated with AF. After multivariable adjustment, AF was associated with cardiovascular events (hazard ratio HR: 2.24; 95% confidence interval CI: 1.06 to 4.75; p = 0.035), heart failure with either reduced or preserved ejection fraction (HR: 4.52; 95% CI: 2.02 to 10.09; p < 0.001), and all-cause mortality (HR: 3.02; 95% CI: 1.73 to 5.27; p < 0.001).
The incidence of AF in the present cohort was comparable to that shown in data of older studies. Obesity has become a major risk factor for incident AF. Although overall cardiovascular event rates were lower in the present study, the present study confirms the association of incident AF with such events.
Progressive remodeling after myocardial infarction (MI) is a leading cause of morbidity and mortality. Recently, glucagon-like peptide (GLP)-1 was shown to have cardioprotective effects, but ...treatment with GLP-1 is limited by its short half-life. It is rapidly degraded by the enzyme dipeptidyl peptidase-4 (DPP-4), an enzyme which inhibits GLP-1 activity. We hypothesized that the DPP-4 inhibitor vildagliptin will increase levels of GLP-1 and may exert protective effects on cardiac function after MI.
Sprague-Dawley rats were either subjected to coronary ligation to induce MI and left ventricular (LV) remodeling, or sham operation. Parts of the rats with an MI were pre-treated for 2 days with the DPP-4 inhibitor vildagliptin (MI-Vildagliptin immediate, MI-VI, 15 mg/kg/day). The remainder of the rats was, three weeks after coronary artery ligation, subjected to treatment with DPP-4 inhibitor vildagliptin (MI-Vildagliptin Late, MI-VL) or control (MI). At 12 weeks, echocardiography and invasive hemodynamics were measured and molecular analysis and immunohistochemistry were performed.
Vildagliptin inhibited the DPP-4 enzymatic activity by almost 70% and increased active GLP-1 levels by about 3-fold in plasma in both treated groups (p < 0.05 vs. non-treated groups). Cardiac function (ejection fraction) was decreased in all 3 MI groups compared with Sham group (p < 0.05); treatment with vildagliptin, either early or late, did not reverse cardiac remodeling. ANP (atrial natriuretic peptide) and BNP (brain natriuretic peptide) mRNA levels were significantly increased in all 3 MI groups, but no significant reductions were observed in both vildagliptin groups. Vildagliptin also did not change cardiomyocyte size or capillary density after MI. No effects were detected on glucose level and body weight in the post-MI remodeling model.
Vildagliptin increases the active GLP-1 level via inhibition of DPP-4, but it has no substantial protective effects on cardiac function in this well established long-term post-MI cardiac remodeling model.
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