Chronic Heart Failure and Comorbid Renal Dysfunction - A Focus on Type 2 Cardiorenal Syndrome

Cardiac and Renal Fibrosis, the Silent Killer in the Cardiovascular Continuum: An Up-to-Date

Cardiovascular disease (CVD) and chronic kidney disease (CKD) often coexist and have a major impact on patient prognosis. Organ fibrosis plays a significant role in the pathogenesis of cardio-renal syndrome (CRS), explaining the high incidence of heart failure and sudden cardiac death in these patients. Various mediators and mechanisms have been proposed as contributors to the alteration of fibroblasts and collagen turnover, varying from hemodynamic changes to the activation of the renin-angiotensin system, involvement of FGF 23, and Klotho protein or collagen deposition. A better understanding of all the mechanisms involved has prompted the search for alternative therapeutic targets, such as novel inhibitors of the renin-angiotensin-aldosterone system (RAAS), serelaxin, and neutralizing interleukin-11 (IL-11) antibodies. This review focuses on the molecular mechanisms of cardiac and renal fibrosis in the CKD and heart failure (HF) population and highlights the therapeutic alternatives designed to target the responsible pathways.

Chronic Kidney Disease Associated with Ischemic Heart Disease: To What Extent Do Biomarkers Help?

Chronic kidney disease represents a complex and multifaceted pathology characterized by the presence of structural or functional renal anomalies associated with a persistent reduction in renal function. As the disease progresses, complications arise due to the chronic inflammatory syndrome, hydro-electrolytic disorders, and toxicity secondary to the uremic environment. Cardiovascular complications are the leading cause of death for these patients. Ischemic cardiac pathology can be both a consequence and complication of chronic kidney disease, highlighting the need to identify specific cardiorenal dysfunction biomarkers targeting pathophysiological mechanisms common to both conditions. This identification is crucial for establishing accurate diagnoses, prognoses, and risk stratifications for patients. This work is intended to elucidate the intricate relationship between chronic kidney disease and ischemic heart disease and to investigate the roles of cardiorenal biomarkers, including cardiac troponin, natriuretic peptides, galectin-3, copeptin, fibroblast growth factor 23 and its co-receptor Klotho, soluble suppression of tumorigenicity 2, and plasma growth differentiation factor 15.

Analysis of the clinical features and risk factors of kidney injury in patients with chronic heart failure-a retrospective cohort study

BACKGROUND

Heart failure (HF) often leads to kidney injury and increased morbidity and mortality. Factors contributing to kidney injury in HF patients had not been elucidated completely. This study sought to comprehensively evaluate the risk factors and clinical features of kidney injury in patients with chronic heart failure (CHF) and to provide more evidence for the management of these patients.

METHODS

Adult patients with CHF admitted to Beijing Anzhen Hospital, Capital Medical University from January 2022 to May 2022 were included in this study. The primary endpoints were the independent risk factors for the development of kidney injury. A multivariate logistic regression model was used for the exploration of the risk factors.

RESULTS

A total of 193 patients were included in this study, of whom 86 (44.5%) developed kidney injury. The independent risk factors for kidney injury in patients with CHF included sex (male) [odds ratio (OR): 4.30, 95% confidence interval (CI): 1.72-10.7, P=0.001], hypertension (OR: 3.68, 95% CI: 1.64-8.29, P=0.001), and stroke (OR: 3.82, 95% CI: 1.25-11.6, P=0.01). Kidney injury was significantly positively correlated with age (OR: 1.03, 95% CI: 1.008-1.06, P=0.01) and potassium (OR: 3.70, 95% CI: 1.58-8.67, P=0.002), and significantly negatively correlated with angiotensin receptor blocker (ARB) application (OR: 0.26, 95% CI: 0.11-0.61, P=0.001), serum albumin concentration (OR: 0.88, 95% CI: 0.81-0.96, P=0.005), hemoglobin concentration (OR: 0.97, 95% CI: 0.95-0.99, P=0.006), and left ventricular ejection fraction (LVEF; OR: 0.95, 95% CI: 0.92-0.98, P=0.01).

CONCLUSIONS

Kidney injury occurred in more than half of the patients with CHF during hospitalization. The independent risk factors for kidney injury in the CHF patients included sex (male), hypertension, and stroke. Kidney injury was positively correlated with age and serum potassium, and negatively correlated with serum albumin, hemoglobin concentration, LVEF, and ARB application.

Chronic Kidney Disease as a Comorbidity in Heart Failure

Heart failure (HF) is one of the greatest problems in healthcare and it often coexists with declining renal function. The pathophysiology between the heart and the kidneys is bidirectional. Common mechanisms leading to the dysfunction of these organs result in a vicious cycle of cardiorenal deterioration. It is also associated with difficulties in the treatment of aggravating HF and chronic kidney disease (CKD) and, as a consequence, recurrent hospitalizations and death. As the worsening of renal function has an undeniably negative impact on the outcomes in patients with HF, searching for new treatment strategies and identification of biomarkers is necessary. This review is focused on the pathomechanisms in chronic kidney disease in patients with HF and therapeutic strategies for co-existing CKD and HF.

The Cardiorenal Axis: Myocardial Perfusion, Metabolism, and Innervation

PURPOSE OF THE REVIEW

Cardiorenal syndrome (CRS), defined as concomitant heart and kidney disease, has been a focus of attention for nearly a decade. As more patients survive severe acute and chronic heart and kidney diseases, CRS has emerged as an "epidemic" of modern medicine. Significant advances have been made in unraveling the complex mechanisms that underlie CRS based on classification of the condition into five pathophysiologic subtypes. In types 1 and 2, acute or chronic heart disease results in renal dysfunction, while in types 3 and 4, acute or chronic kidney diseases are the inciting factors for heart disease. Type 5 CRS is defined as concomitant heart and kidney dysfunction as part of a systemic condition such as sepsis or autoimmune disease.

RECENT FINDINGS

There are ongoing efforts to better define subtypes of CRS based on historical information, clinical manifestations, laboratory data (including biomarkers), and imaging characteristics. Systematic evaluation of CRS by advanced cardiac imaging, however, has been limited in scope and mostly focused on type 4 CRS. This is in part related to lack of clinical trials applying advanced cardiac imaging in the acute setting and exclusion of patients with significant renal disease from studies of such techniques in chronic HF. Advanced cardiac nuclear imaging is well poised for assessment of the pathophysiology of CRS by offering a myriad of molecular probes without the need for nephrotoxic contrast agents. In this review, we examine the current or potential future application of advanced cardiac imaging to evaluation of myocardial perfusion, metabolism, and innervation in patients with CRS.

Heart-kidney interactions: mechanistic insights from animal models

Pathological changes in the heart or kidney can instigate the release of a cascade of cardiorenal mediators that promote injury in the other organ. Combined dysfunction of heart and kidney is referred to as cardiorenal syndrome (CRS) and has gained considerable attention. CRS has been classified into five distinct entities, each with different major pathophysiological changes. Despite the magnitude of the public health problem of CRS, the underlying mechanisms are incompletely understood, and effective intervention is unavailable. Animal models have allowed us to discover pathogenic molecular changes to clarify the pathophysiological mechanisms responsible for heart-kidney interactions and to enable more accurate risk stratification and effective intervention. Here, this article focuses on the use of currently available animal models to elucidate mechanistic insights in the clinical cardiorenal phenotype arising from primary cardiac injury, primary renal disease with special emphasis of chronic kidney disease-specific risk factors, and simultaneous cardiorenal/renocardiac dysfunction. The development of novel animal models that recapitulate more closely the cardiorenal phenotype in a clinical scenario and discover the molecular basis of this condition will be of great benefit.

Gut microbiota and inflammation in chronic kidney disease and their roles in the development of cardiovascular disease

The health and proper functioning of the cardiovascular and renal systems largely depend on crosstalk in the gut-kidney-heart/vessel triangle. Recent evidence suggests that the gut microbiota has an integral function in this crosstalk. Mounting evidence indicates that the development of chronic kidney and cardiovascular diseases follows chronic inflammatory processes that are affected by the gut microbiota via various immune, metabolic, endocrine, and neurologic pathways. Additionally, deterioration of the function of the cardiovascular and renal systems has been reported to disrupt the original gut microbiota composition, further contributing to the advancement of chronic cardiovascular and renal diseases. Considering the interaction between the gut microbiota and the renal and cardiovascular systems, we can infer that interventions for the gut microbiota through diet and possibly some medications can prevent/stop the vicious cycle between the gut microbiota and the cardiovascular/renal systems, leading to a decrease in chronic cardiovascular and renal diseases.

Stem cells transplantation positively modulates the heart-kidney cross talk in cardiorenal syndrome type II

INTRODUCTION

We investigated the effects of human amniotic fluid stem cells (hAFS) and rat adipose tissue stromal vascular fraction GFP-positive cells (rSVC-GFP) in a model of cardio-renal syndrome type II (CRSII).

METHODS AND RESULTS

RHF was induced by monocrotaline (MCT) in 28 Sprague-Dawley rats. Three weeks later, four million hAFS or rSVC-GFP cells were injected via tail vein. BNP, sCreatinine, kidney and heart NGAL and MMP9, sCytokines, kidney and heart apoptosis and cells (Cs) engraftment were evaluated. Cell-treated rats showed a significant reduction of serum NGAL and Creatinine compared to CRSII. In both hAFS and rSVC-GFP group, kidney protein expression of NGAL was significantly lower than in CRSII (hAFS p = 0.036 and rSVC-GFP p < 0.0001) and similar to that of controls. In both hAFS and rSVC-GFP treated rats, we observed cell engraftment in the medulla and differentiation into tubular, endothelial and SMCs cells. Apoptosis was significantly decreased in cell-treated rats (hAFS 14.07 ± 1.38 and rSVC-GFP 12.67 ± 2.96 cells/mm²) and similar to controls (9.85 ± 2.1 cell/mm²). TUNEL-positive cells were mainly located in the kidney medulla. Pro-inflammatory cytokines were down regulated in cell-treated groups and similar to controls. In cell-treated rats, kidney and heart tissue NGAL was not complexed with MMP9 as in CRSII group, suggesting inhibition of MMPs activity.

CONCLUSION

Cell therapy produced improvement in kidney function in rats with CRSII. This was the result of interstitial, vessel and tubular cell engraftment leading to tubular and vessel regeneration, decreased tubular cells apoptosis and mitigated pro-inflammatory milieu. Reduction of NGLA-MMP9 complexes mainly due to decrease MMPs activity prevented further negative heart remodeling.

Chronic kidney disease, worsening renal function and outcomes in a heart failure community setting: A UK national study

BACKGROUND

Routine heart failure (HF) monitoring and management is in the community but the natural course of worsening renal function (WRF) and its influence on HF prognosis is unknown. We investigated the influence of routinely monitored renal decline and related comorbidities on imminent hospitalisation and death in the HF community population.

METHODS

A nested case-control study within an incident HF cohort (N = 50,114) with 12-years follow-up. WRF over 6-months before first hospitalisation and 12-months before death was defined by >20% reduction in estimated glomerular filtration rate (eGFR). Additive interactions between chronic kidney disease (CKD) and comorbidities were investigated.

RESULTS

Prevalence of CKD (eGFR<60 ml/min/1.73m2) in the HF community was 63%, which was associated with an 11% increase in hospitalisation and 17% in mortality. Both risk associations were significantly worse in the presence of diabetes. Compared to HF patients with eGFR,60-89, there was no or minimal increase in risk for mild to moderate CKD (eGFR,30-59) for both outcomes. Adjusted risk estimates for hospitalisation were increased only for severe CKD(eGFR,15-29); Odds Ratio 1.49 (95%CI;1.36,1.62) and renal failure(eGFR,<15); 3.38(2.67,4.29). The relationship between eGFR and mortality was U-shaped; eGFR, ≥90; 1.32(1.17,1.48), eGFR,15-29; 1.68(1.58,1.79) and eGFR,<15; 3.04(2.71,3.41). WRF is common and associated with imminent hospitalisation (1.50;1.37,1.64) and mortality (1.92;1.79,2.06).

CONCLUSIONS

In HF, the risk associated with CKD differs between the community and the acute HF setting. In the community setting, moderate CKD confers no risk but severe CKD, WRF or CKD with other comorbidities identifies patients at high risk of imminent hospitalisation and death.