Of heart and kidney: a complicated love story

Correlation analysis of low-level serum uric acid and cardiovascular events in patients on peritoneal dialysis

Background

The impact of serum uric acid (SUA) on development of cardiovascular disease (CVD) in patients undergoing peritoneal dialysis (PD) remains controversial, especially the impact of hypouricemia (HUA) on CVD. The aim of our study was to investigate the influence of low-level SUA on cardiovascular (CV) events in PD patients.

Methods

A retrospective cohort study was conducted.728 PD patients from February 1, 2010 to May 31, 2019 were enrolled. All demographic and laboratory data were collected at baseline and 6 months after PD treatment. The study cohort was divided into four groups according to SUA level (μmol/L) after 6 months of PD: Group1 (< 360), Group2 (360–420), Group3 (420–480), Group4 (≥ 480). The clinical characteristics of each group were analyzed. With Group2 as reference, logistic regression analysis was performed to investigate the correlation between SUA levels and risk of CV events in patients undergoing PD. Use Kaplan–Meier method to generate CV events risk graph.

Results

728 patients were enrolled in this study, including 403 (55.4%) males and 325 (44.6%) females, with an average age of 48.66 ± 13.98 years; of which 158 (21.7%) patients developed CV events. Multivariate COX regression showed that after adjusting for multiple clinical factors, Group1 (HR = 1.92, 95% CI 1.17–3.15, P = 0.01), Group3 (HR = 1.89, 95% CI 1.13–3.15, P = 0.015), and Group4 (HR = 2.38, 95% CI 1.35–4.19, P = 0.003) are all independent risk factors for developing CV events. The Kaplan–Meier risk curve of CV events showed that the risk of CV events in the Group1, Group3 and Group4 were significantly higher (Log-Rank = 12.67; P = 0.005). Restricted cubic spline (RCS) showed that SUA level is non-linearly associated with the risk of CV events, showing an U-shaped curve (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\chi_{4}^{2}$$\end{document}χ42=13.3 P = 0.01).

Conclusions

Our study suggested that patients with SUA level less than 360 μmol/L also exhibited the higher risk for developing CV events, an U-shaped association between SUA level and risk of CV events in patients undergoing PD. Both SUA levels below 360 μmol/L and above 420 μmol/L were found to be significant risk factors for developing CV events in patients undergoing long-term PD.

Preventive Aspects of Early Resveratrol Supplementation in Cardiovascular and Kidney Disease of Developmental Origins

The increase in the incidence of cardiovascular diseases (CVDs) and kidney disease has stimulated research for strategies that could prevent, rather than just treat, both interconnected disorders. Resveratrol, a polyphenolic compound with pleiotropic biofunctions, has shown health benefits. Emerging epidemiological data supports that early life environmental insults are regarded as increased risks of developing CVDs and kidney disease in adulthood. Conversely, both disorders could be reversed or postponed by shifting interventions from adulthood to earlier stage by so-called reprogramming. The purpose of this review is first to highlight current epidemiological studies linking cardiovascular and renal programming to resulting CVD and kidney disease of developmental origins. This will be followed by a summary of how resveratrol could exert a positive influence on CVDs and kidney disease. This review also presents an overview of the evidence documenting resveratrol as a reprogramming agent to protect against CVD and kidney disease of developmental origins from animal studies and to outline the advances in understanding the underlying molecular mechanisms. Overall, this review reveals the need for future research to further clarify the reprogramming effects of resveratrol before clinical translation.

Protective effects of SGLT-2 inhibitors across the cardiorenal continuum: two faces of the same coin

The cardiovascular and renal systems are closely interconnected in health and disease. Disorders affecting one of these systems frequently involve the other. Both diseases progress through a continuous chain of events, defined as the 'cardiorenal continuum', which is initiated by risk factors that lead to subclinical disease, clinical events, and ultimately to heart failure and end-stage kidney disease. Previous studies have shown that interventions anywhere along this chain of events can interrupt the pathophysiological cascade and provide cardiovascular and/or kidney 'protection'. More recently, clinical trials with SGLT-2 inhibitors (SGLT2i) have shown a significant reduction in cardiovascular and kidney outcomes. Evidence from EMPA-REG OUTCOME, CANVAS Program, DECLARE-TIMI 58, VERTIS-CV, CREDENCE, and more recently DAPA-HF, EMPEROR-Reduced, and DAPA-CKD show that the beneficial effects of SGLT2i are observed across all stages of the cardiorenal continuum, ranging from patients with diabetes and multiple risk factors to those with established cardiovascular disease and even independently of diabetes status. This review provides a critical appraisal of the efficacy and safety of SGLT2i, demonstrating that this is a novel way to disrupt the chain of pathological events in the cardiorenal continuum and prevent cardiovascular and kidney disease in patients with and without diabetes.

Trimethylamine-N-oxide acutely increases cardiac muscle contractility

Cardiovascular disease is a major cause of morbidity and mortality among patients with chronic kidney disease (CKD). Trimethylamine-N-oxide (TMAO), a uremic metabolite that is elevated in the setting of CKD, has been implicated as a nontraditional risk factor for cardiovascular disease. While association studies have linked elevated plasma levels of TMAO to adverse cardiovascular outcomes, its direct effect on cardiac and smooth muscle function remains to be fully elucidated. We hypothesized that pathological concentrations of TMAO would acutely increase cardiac and smooth muscle contractility. These effects may ultimately contribute to cardiac dysfunction during CKD. High levels of TMAO significantly increased paced, ex vivo human cardiac muscle biopsy contractility (P < 0.05). Similarly, TMAO augmented contractility in isolated mouse hearts (P < 0.05). Reverse perfusion of TMAO through the coronary arteries via a Langendorff apparatus also enhanced cardiac contractility (P < 0.05). In contrast, the precursor molecule, trimethylamine (TMA), did not alter contractility (P > 0.05). Multiphoton microscopy, used to capture changes in intracellular calcium in paced, adult mouse hearts ex vivo, showed that TMAO significantly increased intracellular calcium fluorescence (P < 0.05). Interestingly, acute administration of TMAO did not have a statistically significant influence on isolated aortic ring contractility (P > 0.05). We conclude that TMAO directly increases the force of cardiac contractility, which corresponds with TMAO-induced increases in intracellular calcium but does not acutely affect vascular smooth muscle or endothelial function of the aorta. It remains to be determined if this acute inotropic action on cardiac muscle is ultimately beneficial or harmful in the setting of CKD.NEW & NOTEWORTHY We demonstrate for the first time that elevated concentrations of TMAO acutely augment myocardial contractile force ex vivo in both murine and human cardiac tissue. To gain mechanistic insight into the processes that led to this potentiation in cardiac contraction, we used two-photon microscopy to evaluate intracellular calcium in ex vivo whole hearts loaded with the calcium indicator dye Fluo-4. Acute treatment with TMAO resulted in increased Fluo-4 fluorescence, indicating that augmented cytosolic calcium plays a role in the effects of TMAO on force production. Lastly, TMAO did not show an effect on aortic smooth muscle contraction or relaxation properties. Our results demonstrate novel, acute, and direct actions of TMAO on cardiac function and help lay the groundwork for future translational studies investigating the complex multiorgan interplay involved in cardiovascular pathogenesis during CKD.

Association between changes in the mRNA expression of platelet-activating factor receptor in peripheral blood mononuclear cells and progression of diabetic nephropathy

Introduction

Several studies have recently pointed out the role of many inflammatory mediators in the progression of diabetes complications. We had previously demonstrated that mRNA expression of platelet-activating factor receptor (PAFR) in peripheral blood mononuclear cells (PBMCs) was associated with urinary albumin to creatinine ratio (ACR) and forearm flow-mediated dilatation in patients with type 2 diabetes. In an attempt to elucidate this association, patients were followed up for 1 year.

Materials and methods

We recruited 95 patients from the hospital outpatient clinic, among whom 86 were followed up for 1 year (normoalbuminuria: 40 patients, microalbuminuria: 25 patients, macroalbuminuria: 21 patients). We then measured their baseline and 12 month characteristics and collected blood samples to extract PBMCs and measure gene expressions.

Results

Despite higher mRNA expression of PAFR in PBMCs among patients with macroalbuminuria, the rise in its value was not associated with biomarkers of nephropathy, while baseline values were not associated with progression of nephropathy. Moreover, changes in mRNA expression of PAFR were correlated with changes in ACR in all patients (r = 0.225, p = 0.037) and estimated glomerular filtration rate in patients with macroalbuminuria (r =  - 0.438, p = 0.047) during the follow-up period.

Conclusion

Our findings indicate that even though no causal relationship exists between diabetic nephropathy and elevated expression of PAFR in PBMCs, their close association signifies the presence of another common mechanism that could induce both events. Given these findings, the PAF/PAFR interaction could clarify corresponding mechanisms involved in diabetic complications.

Anesthesia for Patients with Concomitant Cardiac and Renal Dysfunction

Renal disease and cardiovascular disease are commonly encountered in the same patient. The dynamic interactions between renal disease and cardiovascular disease have an impact on perioperative management. Renal failure is an independent risk factor for cardiovascular disease and the link between the two disease states remains to be fully elucidated.

Vitamin D nutritional status and the risk for cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality. CVD has a significant impact on health care systems worldwide and over 23 million individuals are expected to succumb to the disease by 2030. Early onset of atherosclerosis in childhood along with other risk factors of CVD, including elevated circulating lipids, have been shown to persist in adulthood and lead to CVD. Vitamin D deficiency is considered a risk factor for the pathogenesis of CVD, with childhood nutritional status of vitamin D being an important determinant of the development of CVD. Low levels of 25-hydroxyvitamin D can arise due to reduced intake as well as geographical location, and other diseases/conditions such as chronic kidney disease and obesity. Childhood vitamin D deficiency can progress and lead to atherosclerosis and other CVDs in adulthood. Early intervention with vitamin D supplementation is an ideal approach towards preventive therapy. However, there is no clear consensus regarding the role of vitamin D in childhood CVD. In the present study, we reviewed the available evidence in favor of and against such a role for this vitamin.

Utility of galectin-3 as a prognostic biomarker in heart failure: where do we stand?

BACKGROUND

Heart failure (HF) continues to be an illness of daunting proportions with a four- year mortality touching 50%. Biomarkers for prognosticating patients with heart failure have generated immense interest. Several studies have been conducted on a novel biomarker, galectin-3 to assess its prognostic effect in heart failure populations. However, the studies have generated conflicting results. Hence a systematic review was done to assess the utility of galectin-3 as a prognostic biomarker in HF.

DESIGN

This study was a systematic review.

METHODS

A literature search was done using terms 'galectin-3 and heart' and 'galectin-3 and heart failure' in MEDLINE, Science Direct, Scopus, Springer Link, Cochrane Library and Google Scholar for original articles using a predefined inclusion/exclusion criteria.

RESULTS

Altogether 27 original articles were selected for the systematic review. Multivariate analysis showed galectin-3 to be ineffective in predicting all-cause mortality and cardiovascular mortality especially under the influence of factors such as estimated glomerular filtration rate (eGFR), left ventricular ejection fraction (LVEF) and N-terminal pro-B-type natriuretic peptide (NTproBNP). Galectin-3 was not found to be superior to NTproBNP, sST2, GDF-15 or C-reactive protein (CRP) as a predictor of mortality. However the combination of natriuretic peptides and galectin-3 has been observed to be superior in predicting mortality compared to either of the biomarkers alone. The role of galectin-3 in remodelling has not been conclusively proven as seen in earlier pre-clinical studies.

CONCLUSION

The current weight of evidence does not suggest galectin-3 to be a predictor of mortality. However, assessment of galectin-3 in a multi-biomarker panel may have a distinct advantage in prognosticating patients with heart failure.

Increased cardiovascular mortality associated with gout: a systematic review and meta-analysis

BACKGROUND

Hyperuricaemia, the biochemical precursor to gout, has been shown to be an independent risk factor for mortality from cardiovascular disease (CVD), although studies examining the clinical phenomenon of gout and risk of CVD mortality report conflicting results. This study aimed to produce a pooled estimate of risk of mortality from cardiovascular disease in patients with gout.

DESIGN

Systematic review and meta-analysis.

METHODS

Electronic bibliographic databases were searched from inception to November 2012, with results reviewed by two independent reviewers. Studies were included if they reported data on CVD mortality in adults with gout who were free of CVD at time of entry into the study. Pooled hazard ratios (HRs) for this association were calculated both unadjusted and adjusted for traditional vascular risk factors.

RESULTS

Six papers, including 223,448 patients, were eligible for inclusion (all (CVD) mortality n = 4, coronary heart disease (CHD) mortality n = 3, and myocardial infarction mortality n = 3). Gout was associated with an excess risk of CVD mortality (unadjusted HR 1.51 (95% confidence interval, CI, 1.17-1.84)) and CHD mortality (unadjusted HR 1.59, 95% CI 1.25-1.94)). After adjusting for traditional vascular risk factors, the pooled HR for both CVD mortality (HR 1.29, 95% CI 1.14-1.44) and CHD mortality (HR 1.42, 95% CI 1.22-1.63) remained statistically significant, but none of the studies reported a significant association with myocardial infarction.

CONCLUSIONS

Gout increases the risk of mortality from CVD and CHD, but not myocardial infarction, independently of vascular risk factors.