Pathophysiology of the cardio-renal syndromes types 1-5: An uptodate

Examining the impact of renal dysfunction and diabetes on post-myocardial infarction mortality: insights from a comprehensive retrospective cohort study across different age groups

Aim. Chronic kidney disease (CKD) and diabetes mellitus (DM) contribute significantly to cardiovascular disease (CVD) and mortality, with prevalence increasing. The evolving demographic of myocardial infarction (MI) patients, influenced by sedentary lifestyles and advanced medical care, lacks understanding regarding the interplay of CKD, DM, age, and post-MI mortality. This study aims to address this gap by evaluating the long-term impact of CKD and DM on post-MI mortality across age groups. Methods. A retrospective cohort study utilized data from the Estonian Myocardial Infarction Registry (EMIR), Estonian Population Register (EPR), and six major hospitals in Estonia, covering AMI hospitalizations from 2012 to 2019. Statistical analyses included Cox proportional hazards regression models and Kaplan-Meier's curves. Results. Analysis of 17,085 MI patients revealed age-dependent associations between renal function and mortality. In patients <65 years, even minor decreases in renal function increased both short-term (HR 2.79, 95% CI 1.71-4.55) and long-term (HR 1.24, 95% CI 1.05-1.47) mortality. Mortality significantly increased in patients >80 years only below an estimated glomerular filtration rate (eGFR) of 44 ml/min/1.73 m2. Newly diagnosed DM patients exhibited higher mortality rates (average HR 1.53, 95% CI 1.45-1.62), while pre-DM did not significantly differ from non-DM patients across all age groups. The DM-renal failure interaction did not significantly influence mortality. Conclusions. An age-dependent association between eGFR and post-MI outcomes emphasizes the need for personalized therapeutic approaches considering age-specific eGFR thresholds and comorbidities to optimize patient management.

Biomarkers in cardiorenal syndrome, a potential use in precision medicine

Cardiorenal syndrome refers to the interrelated dysfunction of the heart or kidney resulting in a cascade of feedback mechanisms, hemodynamic, neurohormonal, and immunological and/or biochemical feedback pathways causing damage in the other organ. Cardiorenal syndrome is categorized into five clinical subtypes depending on the perceived primary precipitant of organ injury and is associated with high morbidity and mortality. Therefore, the development of tools for the earliest identification of cardiorenal syndrome in hospitalized patients is of extremely high significance to ameliorate the prognosis and outcome of these patients. There is increasing interest in identifying molecules serving as biomarkers, reflecting hemodynamic changes, heart and kidney damage and/or dysfunction and oxidative stress-induced cell damage or changes in the extracellular matrix of both the heart and kidneys. Biomarkers provide important insights into the pathophysiology of cardiorenal syndrome and are invaluable tools to predict the decrease in renal function during cardiac dysfunction and vice versa. Based on the pathophysiological mechanisms of cardiorenal syndrome, we reviewed and evaluated the available literature on serum and urinary biomarkers as predictors of kidney and/or heart injury. In addition, heart- and kidney-specific biomarkers were also evaluated based on their reference to kidney and cardiac (dys)function respectively, and whether they would provide any prediction and prognostication of cardiorenal syndrome. In this article, we discuss the current knowledge on the pathophysiology of different types of cardiorenal syndrome, examine the clinical utility of candidate biomarkers in the early diagnosis of cardiorenal syndrome, and guide treatment by evaluating the respective roles of the involved pathophysiological pathways.

Biomarker for cardiorenal syndrome risk in patients with liver cirrhosis and type 2 diabetes in Saudi Arabia

OBJECTIVES

To evaluate the correlation between different attributes, levels of biomarkers, and the probability of developing cardiorenal syndrome (CRS) in patients who have been diagnosed with type 2 diabetes mellitus (T2DM) and liver cirrhosis (LC). The hypothesis suggests that liver illness may be linked to renal impairment, cardiac dysfunction, and the development of cardiorenal syndrome METHODS: The current study retrospectively assessed the medical records of patients who had LC and T2DM diagnoses and were hospitalized at Al Madina Al Munwara hospitals in 2022 and 2023.

RESULTS

This research investigated T2DM patients with physician-confirmed to have LC. Poor glycemic control is indicated by high blood glucose and glycated hemoglobin (HbA1c) readings in research participants. High blood pressure, atherogenic plasma indicator (AIP), and obesity plagued most of these individuals. High creatinine, moderate estimated Glomerular Filtration Rate (eGFR) decline, and a modest urinary albumin-to-creatinine (UACR) rise were the most prevalent variables in LC and T2DM patients. Cardiorenal syndrome risk factors, including elevated blood pressure, triglyceride levels, body mass index (BMI), and high-sensitivity C-reactive protein (hs-CRP) concentrations, were identified through logistic regression. It has been demonstrated that the prevalence of these risk factors increases with age; women may be at a greater risk for developing CRS. Specific biomarker evaluations classified 108 (22.6%) LC and T2DM patients at high risk for chronic kidney disease (CKD), 100 (20%) at risk for cardiovascular disease (CVD), and 91 (18.2%) at risk for CRS.

CONCLUSION

The current assessment included 500 patients with T2DM and LC. The risk factors for CRS identified in this study included elevated cholesterol and triglyceride levels, high BMI, and elevated blood pressure, with age being a significant factor, particularly in female patients. Early identification of these characteristics in patients with LC and T2DM could aid in mitigating the progression of chronic illnesses and their associated complications.

Clinically Evident Cardiopulmonary Congestion Does Not Significantly Impact the Prognosis of Patients With Septic Acute Kidney Injury

Background

Acute kidney injury (AKI) is a common issue among in-hospital patients, with high mortality rates. Sepsis is a primary cause of AKI, particularly in the intensive care unit. Patients with septic AKI often experience cardiovascular congestion, leading to the formal classification of cardiorenal syndrome type 5. The study aimed to evaluate the prognosis of septic AKI patients with and without clinical evidence of cardiovascular congestion.

Methods

This was a retrospective observational study. AKI patients were identified using the in-hospital AKI alert system. Sepsis was diagnosed based on laboratory, clinical, and hemodynamic characteristics, with additional consideration of the quickSOFA score. Cardiovascular congestion was diagnosed by assessing clinical (edema), radiographic (pulmonary congestion), echocardiographic (e.g., wall motion abnormalities), and laboratory variables (e.g., N-terminal pro-B-type natriuretic peptide). Endpoints included in-hospital survival, the need for kidney replacement therapy (KRT), and recovery of kidney function (ROKF).

Results

In total, 102 patients were included, and cardiopulmonary congestion was diagnosed in 78.4%. Individuals with congestion did not differ from patients without congestion in any of the pre-defined endpoints.

Conclusions

It is justified not to consider clinically apparent cardiovascular congestion in septic AKI patients as a risk factor for death per se. Rather, especially in the case of sepsis, clinically apparent positive fluid balance does not seem to be a disadvantage in terms of survival, KRT, and ROKF.

Sacubitril/Valsartan Improves Cardiac Function in Dialysis Patients

Heart failure (HF) is characterized by the activation of adverse neurohormonal systems and a high mortality rate. Noteworthy, HF is a well-known complication of chronic kidney disease (CKD), especially in end-stage kidney disease (ESKD), where dialysis patients are seven to eight times more likely to encounter cardiac arrest than the general population. Therefore, it is important to develop efficient treatments to improve cardiac function in dialysis patients and eventually reduce the cardiovascular death toll. Sacubitril/valsartan (Sac/Val) is a dual inhibitor/blocker of the neprilysin and angiotensin II receptors, which exert cardioprotective effects among patients with heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved EF (HFpEF). Unfortunately, the drug is not approved for subjects with advanced CKD or dialysis patients due to safety concerns. The current study examined the cardiac effects of Sac/Val in HD patients. Administration of Sac/Val (100-400 mg/day) to 12 hemodialysis (HD) patients with HFrEF for six months gradually improved ejection fraction (EF) independently of morphological changes in cardiac geometry, as assessed by echocardiography (ECHO), and hemodynamic alterations. Interestingly, the Cardiomyopathy Questionnaire (Kansas City KCCQ-12) revealed that quality of life significantly improved after Sac/Val treatment. No major adverse effects were reported in the present study, supporting the safety of Sac/Val at least in these patients and for the applied follow-up period. Collectively, these findings support the use of Sac/Val as a cardioprotective agent in both HD and peritoneal dialysis (PD) patients. Yet, a more comprehensive study is required to establish these findings and to extend the follow-up period for 12 months in order to solidify these encouraging results.

Chronic kidney disease activates the HDAC6-inflammatory axis in the heart and contributes to myocardial remodeling in mice: inhibition of HDAC6 alleviates chronic kidney disease-induced myocardial remodeling

Chronic kidney disease (CKD) adversely affects the heart. The underlying mechanism and the interplay between the kidney and the heart are still obscure. We examined the cardiac effect using the unilateral ureteral obstruction (UUO)-induced CKD pre-clinical model in mice. Echocardiography, histopathology of the heart, myocardial mRNA expression of ANP and BNP, the extent of fibrotic (TGF-β, α-SMA, and collagen I) and epigenetic (histone deacetylases, namely HDAC3, HDAC4, and HDAC6) proteins, and myocardial inflammatory response were assessed. Six weeks of post-UUO surgery, we observed a compromised left-ventricular wall thickness and signs of cardiac hypertrophy, accumulation of fibrosis associated, and inflammatory proteins in the heart. In addition, we observed a perturbation of epigenetic proteins, especially HDAC3, HDAC4, and HDAC6, in the heart. Pharmacological inhibition of HDAC6 using ricolinostat (RIC) lessened cardiac damage and improved left-ventricular wall thickness. The RIC treatment substantially restored the serum cardiac injury markers, namely creatine kinase-MB and lactate dehydrogenase (LDH) activities, ANP and BNP mRNA expression, and heart histological changes. The extent of myocardial fibrotic proteins, phospho-NF-κB (p65), and pro-inflammatory cytokines (TNF-α, IL-18, and IL-1β) were significantly decreased in the RIC treatment group. Further findings revealed the CKD-induced infiltration of CD3, CD8a, CD11c, and F4/80 positive inflammatory cells in the heart. Treatment with RIC substantially reduced the myocardial infiltration of these inflammatory cells. From these findings, we believe that CKD-induced myocardial HDAC6 perturbation has a deteriorative effect on the heart, and inhibition of HDAC6 can be a promising approach to alleviate CKD-induced myocardial remodeling.

Occurrence of cardiovascular events in 168 cats with acute urinary tract obstruction

Background

Cardiovascular dysfunction associated with acute kidney injury has been recently described in veterinary medicine, but limited information is available for cats with urinary tract obstruction (UTO).

Objective

This retrospective study aimed to describe the type, frequency, timeline, and risk factors for cardiovascular events (CVEs) in cats treated for acute UTO.

Animals and procedures

Medical records of cats admitted to the intensive care unit for either upper (ureteral: UUTO) or lower (urethral: LUTO) UTO from 2016 to 2021 were reviewed. Cardiovascular events were defined as development of arrhythmia, heart murmur or gallop sound, clinical signs consistent with fluid overload (CRFO), or decreased tissue perfusion (DTP).

Results

One hundred and sixty-eight cats with UTO were recruited (56 with UUTO and 112 with LUTO). Cardiovascular events were reported in 61.9% of cases, including arrhythmia (33.6%), gallop rhythm (28.1%), heart murmur (15.3%), CRFO (14.4%), and DTP (8.6%). Potassium concentration, preexisting chronic kidney disease, and renal pelvic dilation at abdominal ultrasonography were associated with CVE occurrence in multivariate analysis.

Conclusions

This study highlighted frequent CVEs in cats treated for UTO, with a potential strong impact on outcome. Therefore, cardiovascular parameters of cats with preexisting chronic kidney disease or those admitted with hyperkalemia or renal pelvic dilation should be closely monitored.

Impact of recombinant human brain natriuretic peptide on emergency dialysis and prognosis in end-stage renal disease patients with type 4 cardiorenal syndrome

Recombinant human brain natriuretic peptide (rhBNP) effects on type 4 cardiorenal syndrome (CRS) and adverse events such as heart failure rehospitalization and all-cause mortality have not been assessed in large-scale research. This study evaluated the impact of rhBNP on emergency dialysis and prognosis in end-stage renal disease (ESRD) patients with type 4 CRS, and the risk factors of emergency dialysis. This retrospective cohort study included patients with type 4 CRS and ESRD admitted for decompensated heart failure between January 2016 and December 2021. Patients were divided into the rhBNP and non-rhBNP cohorts, according to whether they were prescribed rhBNP. The primary outcomes were emergency dialysis at first admission and cardiovascular events within a month after discharge. A total of 77 patients were included in the rhBNP cohort (49 males and 28 females, median age 67) and 79 in the non-rhBNP cohort (47 males and 32 females, median age 68). After adjusting for age, residual renal function, and primary diseases, Cox regression analysis showed that rhBNP was associated with emergency dialysis (HR = 0.633, 95% CI 0.420-0.953) and cardiovascular events (HR = 0.410, 95% CI 0.159-0.958). In addition, multivariate logistic regression analysis showed that estimated glomerular filtration rate (eGFR) (OR = 0.782, 95% CI 0.667-0.917, P = 0.002) and procalcitonin (PCT) levels (OR = 1.788, 95% CI 1.193-2.680, P = 0.005) at the first visit were independent risk factors for emergency dialysis while using rhBNP was a protective factor for emergency dialysis (OR = 0.195, 95% CI 0.084-0.451, P < 0.001). This study suggests that RhBNP can improve cardiac function and reduce the occurrence of emergency dialysis and cardiovascular events in ESRD patients with type 4 CRS.

Kynurenic acid, a key L-tryptophan-derived metabolite, protects the heart from an ischemic damage

BACKGROUND

Renal injury induces major changes in plasma and cardiac metabolites. Using a small- animal in vivo model, we sought to identify a key metabolite whose levels are significantly modified following an acute kidney injury (AKI) and to analyze whether this agent could offer cardiac protection once an ischemic event has occurred.

METHODS AND RESULTS

Metabolomics profiling of cardiac lysates and plasma samples derived from rats that underwent AKI 1 or 7 days earlier by 5/6 nephrectomy versus sham-operated controls was performed. We detected 26 differential metabolites in both heart and plasma samples at the two selected time points, relative to sham. Out of which, kynurenic acid (kynurenate, KYNA) seemed most relevant. Interestingly, KYNA given at 10 mM concentration significantly rescued the viability of H9C2 cardiac myoblast cells grown under anoxic conditions and largely increased their mitochondrial content and activity as determined by flow cytometry and cell staining with MitoTracker dyes. Moreover, KYNA diluted in the drinking water of animals induced with an acute myocardial infarction, highly enhanced their cardiac recovery according to echocardiography and histopathology.

CONCLUSION

KYNA may represent a key metabolite absorbed by the heart following AKI as part of a compensatory mechanism aiming at preserving the cardiac function. KYNA preserves the in vitro myocyte viability following exposure to anoxia in a mechanism that is mediated, at least in part, by protection of the cardiac mitochondria. A short-term administration of KYNA may be highly beneficial in the treatment of the acute phase of kidney disease in order to attenuate progression to reno-cardiac syndrom and to reduce the ischemic myocardial damage following an ischemic event.

Sex differences in Cardiorenal Syndrome: Insights from CARDIOREN Registry

PURPOSE OF THE WORK

Although sex-specific differences in heart failure (HF) or kidney disease (KD) have been analyzed separately, the predominant cardiorenal phenotype by sex has not been described. This study aims to explore the sex-related differences in cardiorenal syndrome (CRS) in a contemporary cohort of outpatients with HF.

FINDINGS

An analysis of the Cardiorenal Spanish registry (CARDIOREN) was performed. CARDIOREN Registry is a prospective multicenter observational registry including 1107 chronic ambulatory HF patients (37% females) from 13 Spanish HF clinics. Estimated Glomerular Filtration Rate (eGFR) < 60 ml/min/1.73 m2 was present in 59.1% of the overall HF population, being this prevalence higher in the female population (63.2% vs. 56.6%, p = 0.032, median age: 81 years old, IQR:74-86). Among those with kidney dysfunction, women displayed higher odds of showing HF with preserved ejection fraction (HFpEF) (odds ratio [OR] = 4.07; confidence interval [CI] 95%: 2.65-6.25, p < 0.001), prior valvular heart disease (OR = 1.76; CI 95%:1.13-2.75, p = 0.014), anemia (OR: 2.02; CI 95%:1.30-3.14, p = 0.002), more advanced kidney disease (OR for CKD stage 3: 1.81; CI 95%:1.04-3.13, p = 0.034; OR for CKD stage 4: 2.49, CI 95%:1.31-4.70, p = 0.004) and clinical features of congestion (OR:1.51; CI 95%: 1.02-2.25, p = 0.039). On the contrary, males with cardiorenal disease showed higher odds of presenting HF with reduced ejection fraction (HFrEF) (OR:3.13; CI 95%: 1.90-5.16, p < 0.005), ischemic cardiomyopathy (OR:2.17; CI 95%: 1.31-3.61, p = 0.003), hypertension (OR = 2.11; CI 95%:1.18-3.78, p = 0.009), atrial fibrillation (OR:1.71; CI 95%: 1.06-2.75, p = 0.025), and hyperkalemia (OR:2.43, CI 95%: 1.31-4.50, p = 0.005). In this contemporary registry of chronic ambulatory HF patients, we observed sex-related differences in patients with combined heart and kidney disease. The emerging cardiorenal phenotype characterized by advanced CKD, congestion, and HFpEF was predominantly observed in women, whereas HFrEF, ischemic etiology, hypertension, hyperkalemia, and atrial fibrillation were more frequently observed in men.

A comprehensive review of acute cardio-renal syndrome: need for novel biomarkers

Cardiorenal syndrome represents a wide-spectrum disorder involving the heart and kidneys as the primary affected organs. India has an increasingly high burden of acute CRS, coinciding with the rise in global statistics. Up to 2022, approximately 46.1% of all cardiorenal patients have been diagnosed with acute CRS in India. Acute CRS involves a sudden deterioration of kidney functionalities, referred to as acute kidney injury (AKI) in acute heart failure patients. The pathophysiology of CRS involves hyperactivation of the sympathetic nervous system (SNS) and the renin-angiotensin-aldosterone system (RAAS) following acute myocardial stress. The pathological phenotype of acute CRS is associated with perturbed inflammatory, cellular, and neurohormonal markers in circulation. These complications increase the risk of mortality in clinically diagnosed acute CRS patients, making it a worldwide healthcare burden. Hence, effective diagnosis and early prevention are crucial to prevent the progression of CRS in AHF patients. Present biomarkers, such as serum creatinine (sCr), cystatin C (CysC), glomerular filtration rate (GFR), blood urea nitrogen (BUN), serum and/or urine neutrophil gelatinase-associated lipocalin (NGAL), B-type natriuretic peptide (BNP), and NT-proBNP, are clinically used to diagnose AKI stages in CRS patients but are limitedly sensitive to the early detection of the pathology. Therefore, the need for protein biomarkers is emerging for early intervention in CRS progression. Here, we summarized the cardio-renal nexus in acute CRS, with an emphasis on the present clinicopathological biomarkers and their limitations. The objective of this review is to highlight the need for novel proteomic biomarkers that will curb the burgeoning concern and direct future research trials.

Sacubitril/valsartan: research progress of multi-channel therapy for cardiorenal syndrome

Cardiorenal syndrome (CRS) results from complex interaction between heart and kidneys, inducing simultaneous acute or chronic dysfunction of these organs. Although its incidence rate is increasing with higher mortality in patients, effective clinical treatment drugs are currently not available. The literature suggests that renin-angiotensin-aldosterone system (RAAS) and diuretic natriuretic peptide (NP) system run through CRS. Drugs only targeting the RAAS and NPs systems are not effective. Sacubitril/valsartan contains two agents (sacubitril and valsartan) that can regulate RAAS and NPs simultaneously. In the 2017 American College of Cardiology/American Heart Association/American Heart Failure (HF) ssociation (ACC/AHA/HFSA) guideline, sacubitril/valsartan was recommended as standard therapy for HF patients. The latest research shows that Combined levosimendan and Sacubitril/Valsartan markets are protected the heart and kidney against cardiovascular syndrome in rat. However, fewer studies have reported its therapeutic efficacy in CRS treatment, and their results are inconclusive. Therefore, based on RAAS and NPs as CRS biomarkers, this paper summarizes possible pathophysiological mechanisms and preliminary clinical application effects of sacubitril/valsartan in the prevention and treatment of CRS. This will provide a pharmacological justification for expanding sacubitril/valsartan use to the treatment of CRS.

Sestrin2 Mediates Metformin Rescued the Age-Related Cardiac Dysfunctions of Cardiorenal Syndrome Type 3

Acute kidney injury (AKI) leads to acute cardiac injury and dysfunction in cardiorenal syndrome Type 3 (CRS3) through oxidative stress (OS). The stress-inducible Sestrin2 (Sesn2) protein reduces reactive oxygen species (ROS) accumulation and activates AMP-dependent protein kinase (AMPK) to regulate cellular metabolism and energetics during OS. Sesn2 levels and its protective effects decline in the aged heart. Antidiabetic drug metformin upregulates Sesn2 levels in response to ischemia-reperfusion (IR) stress. However, the role of metformin in CRS3 remains unknown. This study seeks to explore how the age-related decrease in cardiac Sesn2 levels contributes to cardiac intolerance to AKI-induced insults, and how metformin ameliorates CRS3 through Sesn2. Young (3-5 months) and aged (21-23 months) C57BL/6J wild-type mice along with cardiomyocyte-specific knockout (cSesn2-/-) and their wild type of littermate (Sesn2f/f) C57BL/6J mice were subjected to AKI for 15 min followed by 24 h of reperfusion. Cardiac and mitochondrial functions were evaluated through echocardiograms and seahorse mitochondria respirational analysis. Renal and cardiac tissue was collected for histological analysis and immunoblotting. The results indicate that metformin could significantly rescue AKI-induced cardiac dysfunction and injury via Sesn2 through an improvement in systolic and diastolic function, fibrotic and cellular damage, and mitochondrial function in young, Sesn2f/f, and especially aged mice. Metformin significantly increased Sesn2 expression under AKI stress in the aged left-ventricular tissue. Thus, this study suggests that Sesn2 mediates the cardioprotective effects of metformin during post-AKI.

Recent Developments in the Evaluation and Management of Cardiorenal Syndrome: A Comprehensive Review

Cardiorenal syndrome (CRS) is an increasingly recognized diagnostic entity associated with high morbidity and mortality among acutely ill heart failure (HF) patients with acute and/ or chronic kidney diseases (CKD). While traditionally viewed as a state of decline in glomerular filtration rate (GFR) due to decreased renal perfusion, mainly due to therapeutic interventions to relieve congestive in HF, recent insights into the underlying pathophysiologic mechanisms of CRS led to a broader definition and further classification of CRS into 5 distinct types. In this comprehensive review, we discuss the classification of CRS, highlighting the underlying common pathogenetic pathways of heart failure and kidney injury, including increased congestion, neurohormonal dysregulation, oxidative stress as well as inflammation, and cytokine storm that are particularly evident in COVID-19 patients with multiorgan failure and also in those with other disorders including sepsis, systemic lupus erythematosus and amyloidosis. In this review we also present the recent advances in the diagnostic strategies of CRS including cardiac and renal biomarkers as well as advanced cardiac and renal imaging techniques that are available to aid in the diagnosis as well as in the prognostication of this disorder. Finally, we discuss the various therapeutic options available to-date, including fluid optimization, hemofiltration, renal replacement therapy as well as the role of SGLT2 inhibitors in light of recent data from RCTs. It is important to note that, CRS population are either excluded or underrepresented, at best, in major RCTs and therefore, therapeutic recommendations are largely extrapolated from HF and CKD clinical trials.

Immune Cells Are Differentially Modulated in the Heart and the Kidney during the Development of Cardiorenal Syndrome 3

Cardiorenal syndrome type 3 (CRS 3) occurs when there is an acute kidney injury (AKI) leading to the development of an acute cardiac injury. The immune system is involved in modulating the severity of kidney injury, and the role of immune system cells in the development of CRS 3 is not well established. The present work aims to characterize the macrophage and T and B lymphocyte populations in kidney and heart tissue after AKI induced by renal I/R. Thus, C57BL/6 mice were subjected to a renal I/R protocol by occlusion of the left renal pedicle (unilateral) for 60 min, followed by reperfusion for 3, 8 and 15 days. The immune cell populations of interest were identified using flow cytometry, and RT-qPCR was used to evaluate gene expression. As a result, a significant increase in TCD4+, TCD8+ lymphocytes and M1 macrophages to the renal tissue was observed, while B cells in the heart decreased. A renal tissue repair response characterized by Foxp3 activation predominated. However, a more inflammatory profile was shown in the heart tissue influenced by IL-17RA and IL-1β. In conclusion, the AKI generated by renal I/R was able to activate and recruit T and B lymphocytes and macrophages, as well as pro-inflammatory mediators to renal and cardiac tissue, showing the role of the immune system as a bridge between both organs in the context of CRS 3.

Diuretic resistance in patients with kidney disease: Challenges and opportunities

Edema caused by kidney disease is called renal edema. Edema is a common symptom of many human kidney diseases. Patients with renal edema often need to take diuretics.However, After taking diuretics, patients with kidney diseases are prone to kidney congestion, decreased renal perfusion, decreased diuretics secreted by renal tubules, neuroendocrine system abnormalities, abnormal ion transporter transport, drug interaction, electrolyte disorder, and hypoproteinemia, which lead to ineffective or weakened diuretic use and increase readmission rate and mortality. The main causes and coping strategies of diuretic resistance in patients with kidney diseases were described in detail in this report. The common causes of DR included poor diet (electrolyte disturbance and hypoproteinemia due to patients' failure to limit diet according to correct sodium, chlorine, potassium, and protein level) and poor drug compliance (the patient did not take adequate doses of diuretics. true resistance occurs only if the patient takes adequate doses of diuretics, but they are not effective), changes in pharmacokinetics and pharmacodynamics, electrolyte disorders, changes in renal adaptation, functional nephron reduction, and decreased renal blood flow. Common treatment measures include increasing in the diuretic dose and/or frequency, sequential nephron blockade,using new diuretics, ultrafiltration treatment, etc. In clinical work, measures should be taken to prevent or delay the occurrence and development of DR in patients with kidney diseases according to the actual situation of patients and the mechanism of various causes. Currently, there are many studies on DR in patients with heart diseases. Although the phenomenon of DR in patients with kidney diseases is common, there is a relatively little overview of the mechanism and treatment strategy of DR in patients with kidney diseases. Therefore, this paper hopes to show the information on DR in patients with kidney diseases to clinicians and researchers and broaden the research direction and ideas to a certain extent.

What Promotes Acute Kidney Injury in Patients with Myocardial Infarction and Multivessel Coronary Artery Disease-Contrast Media, Hydration Status or Something Else?

Multivessel coronary artery disease (MVCAD) is found in approximately 50% of patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI). Although we have data showing the benefits of revascularization of significant non-culprit coronary lesions in patients with AMI, the optimal timing of angioplasty remains unclear. The most common reason for postponing subsequent percutaneous treatment is the fear of contrast-induced acute kidney injury (CI-AKI). Acute kidney injury (AKI) is common in patients with AMI undergoing PCI, and its etiology appears to be complex and incompletely understood. In this review, we discuss the definition, pathophysiology and risk factors of AKI in patients with AMI undergoing PCI. We present the impact of AKI on the course of hospitalization and distant prognosis of patients with AMI. Special attention was paid to the phenomenon of AKI in patients undergoing multivessel revascularization. We analyze the correlation between increased exposure to contrast medium (CM) and the risk of AKI in patients with AMI to provide information useful in the decision-making process about the optimal timing of revascularization of non-culprit lesions. In addition, we present diagnostic tools in the form of new biomarkers of AKI and discuss ways to prevent and mitigate the course of AKI.

A molecular phenotypic screen reveals that lobetyolin alleviates cardiac dysfunction in 5/6 nephrectomized mice by inhibiting osteopontin

BACKGROUND

Cardiovascular diseases are the major cause of mortality in patients with advanced chronic kidney diseases. The predominant abnormality observed among this population is cardiac dysfunction secondary to myocardial remodelings, such as hypertrophy and fibrosis, emphasizing the need to develop potent therapies that maintain cardiac function in patients with end-stage renal disease.

AIMS

To identify potential compounds and their targets as treatments for cardiorenal syndrome type 4 (CRS) using molecular phenotyping and in vivo/in vitro experiments.

METHODS

Gene expression was assessed using bioinformatics and verified in animal experiments using 5/6 nephrectomized mice (NPM). Based on this information, a molecular phenotyping strategy was pursued to screen potential compounds. Picrosirius red staining, wheat germ agglutinin staining, Echocardiography, immunofluorescence staining, and real-time quantitative PCR (qPCR) were utilized to evaluate the effects of compounds on CRS in vivo. Furthermore, qPCR, immunofluorescence staining and flow cytometry were applied to assess the effects of these compounds on macrophages/cardiac fibroblasts/cardiomyocytes. RNA-Seq analysis was performed to locate the targets of the selected compounds. Western blotting was performed to validate the targets and mechanisms. The reversibility of these effects was tested by overexpressing Osteopontin (OPN).

RESULTS

OPN expression increased more remarkably in individuals with uremia-induced cardiac dysfunction than in other cardiomyopathies. Lobetyolin (LBT) was identified in the compound screen, and it improved cardiac dysfunction and suppressed remodeling in NPM mice. Additionally, OPN modulated the effect of LBT on cardiac dysfunction in vivo and in vitro. Further experiments revealed that LBT suppressed OPN expression via the phosphorylation of c-Jun N-terminal protein kinase (JNK) signaling pathway.

CONCLUSIONS

LBT improved CRS by inhibiting OPN expression through the JNK pathway. This study is the first to describe a cardioprotective effect of LBT and provides new insights into CRS drug discovery.

Cardiorenal syndrome: Pathophysiology as a key to the therapeutic approach in an under-diagnosed disease

Cardiorenal syndrome is a clinical condition that impacts both the heart and the kidneys. One organ's chronic or acute impairment can lead to the other's chronic or acute dysregulation. The cardiorenal syndrome has been grouped into five subcategories that describe the etiology, pathophysiology, duration, and pattern of cardiac and renal dysfunction. This classification reflects the large spectrum of interrelated dysfunctions and underlines the bidirectional nature of heart-kidney interactions. However, more evidence is needed to apply these early findings in medical practice. Understanding the relationship between these two organs during each organ's impairment has significant clinical implications that are relevant for therapy in both chronic and acute conditions. The epidemiology, definition, classification, pathophysiology, therapy, and outcome of each form of cardiorenal syndrome are all examined in this review.

Acute kidney injury in pediatrics: an overview focusing on pathophysiology

Acute kidney injury (AKI) is defined as an abrupt decline in glomerular filtration rate, with increased serum creatinine and nitrogenous waste products due to several possible etiologies. Incidence in the pediatric population is estimated to be 3.9 per 1,000 hospitalizations, and prevalence among children admitted to intensive care units is 26.9%. Despite being a condition with important incidence and morbimortality, further evidence on pathophysiology and management among the pediatric population is still lacking. This narrative review aimed to summarize and discuss current data on AKI pathophysiology in the pediatric population, considering all the physiological particularities of this age range and common etiologies. Additionally, we reported current diagnostic tools, novel biomarkers, and newly proposed medications that have been studied with the aim of early diagnosis and appropriate treatment of AKI in the future.

Kidney disease and congenital heart disease: Partnership for life

The literature on the relationship between kidney and cardiovascular diseases is continuously expanding. Scientists have elucidated many of the neurohormonal and hemodynamic pathways involved in cardiorenal disease. However, little is known about kidney disease in patients with congenital heart disease. Given advances in the medical and surgical care of this highly complex patient population, survival rates have dramatically improved leading to a higher percentage of adults living with congenital heart disease. Accordingly, a noticeable increase in the prevalence of kidney disease is appreciated in these patients. Some of the main risk factors for developing chronic kidney disease in the adult congenital heart disease population include chronic hypoxia, neurohormonal derangements, intraglomerular hemodynamic changes, prior cardiac surgeries from minimally invasive to open heart surgeries with ischemia, and nephrotoxins. Unfortunately, data regarding the prevalence, pathophysiology, and prognosis of chronic kidney disease in the adult congenital heart disease population remain scarce. This has led to a lack of clear recommendations for evaluating and managing kidney disease in these patients. In this review, we discuss contemporary data on kidney disease in adults with congenital heart disease in addition to some of the gaps in knowledge we face. The article highlights the delicate interaction between disease of the heart and kidneys in these patients, and offers the practitioner tools to more effectively manage this vulnerable population.

Toward Human Models of Cardiorenal Syndrome in vitro

Heart and kidney diseases cause high morbidity and mortality. Heart and kidneys have vital functions in the human body and, interestingly, reciprocally influence each other’s behavior: pathological changes in one organ can damage the other. Cardiorenal syndrome (CRS) is a group of disorders in which there is combined dysfunction of both heart and kidney, but its underlying biological mechanisms are not fully understood. This is because complex, multifactorial, and dynamic mechanisms are likely involved. Effective treatments are currently unavailable, but this may be resolved if more was known about how the disease develops and progresses. To date, CRS has actually only been modeled in mice and rats in vivo. Even though these models can capture cardiorenal interaction, they are difficult to manipulate and control. Moreover, interspecies differences may limit extrapolation to patients. The questions we address here are what would it take to model CRS in vitro and how far are we? There are already multiple independent in vitro (human) models of heart and kidney, but none have so far captured their dynamic organ-organ crosstalk. Advanced in vitro human models can provide an insight in disease mechanisms and offer a platform for therapy development. CRS represents an exemplary disease illustrating the need to develop more complex models to study organ-organ interaction in-a-dish. Human induced pluripotent stem cells in combination with microfluidic chips are one powerful tool with potential to recapitulate the characteristics of CRS in vitro. In this review, we provide an overview of the existing in vivo and in vitro models to study CRS, their limitations and new perspectives on how heart-kidney physiological and pathological interaction could be investigated in vitro for future applications.

Relation of Cardiorenal Syndrome to Mitral and Tricuspid Regurgitation in Acute Decompensated Heart Failure

This study aimed to investigate the role of secondary mitral regurgitation (MR) and tricuspid regurgitation (TR) in the pathogenesis of cardiorenal syndrome (CRS). Worsening renal function in patients with acute decompensated heart failure receiving diuretic therapy is defined as CRS and is related to central venous congestion. The role of secondary MR and TR is not well studied. We retrospectively reviewed the electronic medical records of 80 consecutive patients hospitalized with acute decompensated heart failure. Patients were divided into 2 groups: group 1 (CRS) if creatinine increased >0.3 mg/dl from baseline and group 2 (no CRS) if creatinine remained stable or improved with diuretic therapy. Admission creatinine was higher in group 1 compared with group 2 (1.5 vs 1.2 mg/dl, p = 0.033). The magnitude of MR and TR were higher by both visual assessment (moderate to severe [3+] or severe [4+] MR in 68% of patients in group 1 vs 3% in group 2, p <0.0001; 3+ or 4+ TR in 48% of patients in group 1 vs 10% in group 2, p = 0.0004) and by vena contracta (MR 0.6 ± 0.2 cm in group 1 vs 0.4 ± 0.1 cm in group 2, p <0.0001; TR 0.5 ± 0.2 cm in group 1 vs 0.4 ± 0.2 cm in group 2, p = 0.0013). By using receiver operating characteristic curves, MR and TR were the most sensitive parameters in predicting CRS. In conclusion, renal function on admission and moderate to severe or severe MR and TR are highly predictive of the risk of developing CRS.

Beyond the Cardiorenal Syndrome: Pathophysiological Approaches and Biomarkers for Renal and Cardiac Crosstalk

Cardiorenal syndrome encompasses complex multifactorial facets and carries significant morbidity and mortality worldwide. The bi-directional relationship between the heart and kidneys, where dysfunction in one organ worsens the function of the other, has been the leading motor for research in the last few years. In the pathophysiological process, small noncoding RNAs, epigenetics, vascular growth factors, oxidative stress, hemodynamic factors, and biomarkers play a pivotal role in the development of cardiorenal syndrome. It is therefore important to elucidate all the mechanisms in order to provide diagnostic and treatments tools. This review summarizes the hemodynamic and non-hemodynamic pathways along with biomarkers that could be the next target for diagnosis, treatment, and prognosis in cardiorenal syndrome.

Mitochondrial Dysfunction: An Emerging Link in the Pathophysiology of Cardiorenal Syndrome

The crosstalk between the heart and kidney is carried out through various bidirectional pathways. Cardiorenal syndrome (CRS) is a pathological condition in which acute or chronic dysfunction in the heart or kidneys induces acute or chronic dysfunction of the other organ. Complex hemodynamic factors and biochemical and hormonal pathways contribute to the development of CRS. In addition to playing a critical role in generating metabolic energy in eukaryotic cells and serving as signaling hubs during several vital processes, mitochondria rapidly sense and respond to a wide range of stress stimuli in the external environment. Impaired adaptive responses ultimately lead to mitochondrial dysfunction, inducing cell death and tissue damage. Subsequently, these changes result in organ failure and trigger a vicious cycle. In vitro and animal studies have identified an important role of mitochondrial dysfunction in heart failure (HF) and chronic kidney disease (CKD). Maintaining mitochondrial homeostasis may be a promising therapeutic strategy to interrupt the vicious cycle between HF and acute kidney injury (AKI)/CKD. In this review, we hypothesize that mitochondrial dysfunction may also play a central role in the development and progression of CRS. We first focus on the role of mitochondrial dysfunction in the pathophysiology of HF and AKI/CKD, then discuss the current research evidence supporting that mitochondrial dysfunction is involved in various types of CRS.

Cardiorenal syndrome: long road between kidney and heart

Almost 200 years ago, the first evidence described by Robert Bright (1836) showed the strong interaction between the kidneys and heart and, since then, the scientific community has dedicated itself to better understanding the mechanisms involved in the kidney-heart relationship, known in recent decades as cardiorenal syndrome (CRS). This syndrome includes a wide clinical variety that affects the kidneys and heart, in an acute or chronic manner. Moreover, it is well established in the literature that the immune system, the sympathetic nervous system, the renin-angiotensin-aldosterone, and the oxidative stress actively play a strong role in the cellular and molecular processes present in CRS. More recently, uremic molecules and epigenetic factors have been also shown to be key mediators in the development of syndrome. The present review intends to present the state of the art regarding CRS and to show the paths known, until now, in the long road between the kidneys and heart.

Identification and Validation of Pathogenic Genes in Sepsis and Associated Diseases by Integrated Bioinformatics Approach

Sepsis is a clinical syndrome with high mortality and morbidity rates. In sepsis, the abrupt release of cytokines by the innate immune system may cause multiorgan failure, leading to septic shock and associated complications. In the presence of a number of systemic disorders, such as sepsis, infections, diabetes, and systemic lupus erythematosus (SLE), cardiorenal syndrome (CRS) type 5 is defined by concomitant cardiac and renal dysfunctions Thus, our study suggests that certain mRNAs and unexplored pathways may pave a way to unravel critical therapeutic targets in three debilitating and interrelated illnesses, namely, sepsis, SLE, and CRS. Sepsis, SLE, and CRS are closely interrelated complex diseases likely sharing an overlapping pathogenesis caused by erroneous gene network activities. We sought to identify the shared gene networks and the key genes for sepsis, SLE, and CRS by completing an integrative analysis. Initially, 868 DEGs were identified in 16 GSE datasets. Based on degree centrality, 27 hub genes were revealed. The gProfiler webtool was used to perform functional annotations and enriched molecular pathway analyses. Finally, core hub genes (EGR1, MMP9, and CD44) were validated using RT-PCR analysis. Our comprehensive multiplex network approach to hub gene discovery is effective, as evidenced by the findings. This work provides a novel research path for a new research direction in multi-omics biological data analysis.

The value of soluble suppression of tumorigenesis-2 (sST2) in the maintenance of hemodialysis patients with heart failure

BACKGROUND

Patients with end-stage renal disease are prone to develop heart failure (HF). The N-terminal pro-brain natriuretic peptide (NT-proBNP, BNP) is regarded as the gold standard for diagnosing HF. However, its prognostic sensitivity in patients with end-stage renal disease is sub-optimal. Soluble suppression of tumorigenesis-2 (sST2) has been well studied in HF but rarely in patients with maintenance hemodialysis (MHD). This study aimed to evaluate the value of sST2 in predicting HF in MHD patients.

METHODS

Twenty-three patients with New York Heart Association (NYHA) class III-IV were included in the HF group and 88 NYHA class I-II patients in the non-heart failure (NHF) group. sST2 and laboratory indexes were compared between the two groups.

RESULTS

The HF group, compared with the NHF group, presented with higher sST2, more advanced age, higher incidence of coronary heart disease (CHD), left ventricle end-diastolic diameter (LVEDD), and pulmonary artery pressure (PAP), and unchanged parathyroid hormone (iPTH). The HF group also had lower ejection fraction (EF), uric acid, inorganic phosphorus, 25-OH VitD3, and serum albumin. Multivariate logistic regression indicated that age, BNP, and sST2 were independent risk factors of HF in MHD patients. Spearman analysis defined that sST2 was positively correlated with PAP (r =0.283, p =0.003) and C-reactive protein (r =0.354, p <0.001); and negatively correlated with sex (r =-0.255, p =0.007), albumin (r =-0.366, p <0.001), uric acid (r =-0.213, p =0.025), 25-OH VitD3 (r =-0.216, p =0.04), calcium (r =-0.219, p =0.021), and inorganic phosphorus (r =-0.256, p =0.007). Receiver operating characteristic curve analysis determined a positive association between BNP and sST2 (r =0.373, p <0.001), with the area under the curve (AUC) of BNP being 0.822 (sensitivity: 0.783, specificity: 0.830) and the AUC of sST2 being 0.841 (sensitivity: 0.913, specificity: 0.761). The AUC of sST2 was 0.841, and the cut-value was 42.840 (sensitivity: 0.913, specificity: 0.761).

CONCLUSION

sST2 can predict HF in MHD patients and facilitate early diagnosis and prevention of HF in MHD patients. HIPPOKRATIA 2022, 26 (1):19-24.

Extracellular Vesicles and Their Relationship with the Heart-Kidney Axis, Uremia and Peritoneal Dialysis

Cardiorenal syndrome (CRS) is described as primary dysfunction in the heart culminating in renal injury or vice versa. CRS can be classified into five groups, and uremic toxin (UT) accumulation is observed in all types of CRS. Protein-bound uremic toxin (PBUT) accumulation is responsible for permanent damage to the renal tissue, and mainly occurs in CRS types 3 and 4, thus compromising renal function directly leading to a reduction in the glomerular filtration rate (GFR) and/or subsequent proteinuria. With this decrease in GFR, patients may need renal replacement therapy (RRT), such as peritoneal dialysis (PD). PD is a high-quality and home-based dialysis therapy for patients with end-stage renal disease (ESRD) and is based on the semi-permeable characteristics of the peritoneum. These patients are exposed to factors which may cause several modifications on the peritoneal membrane. The presence of UT may harm the peritoneum membrane, which in turn can lead to the formation of extracellular vesicles (EVs). EVs are released by almost all cell types and contain lipids, nucleic acids, metabolites, membrane proteins, and cytosolic components from their cell origin. Our research group previously demonstrated that the EVs can be related to endothelial dysfunction and are formed when UTs are in contact with the endothelial monolayer. In this scenario, this review explores the mechanisms of EV formation in CRS, uremia, the peritoneum, and as potential biomarkers in peritoneal dialysis.

Effects of Cardiac Resynchronization Therapy on Cardio-Respiratory Coupling

In this study, the effect of cardiac resynchronization therapy (CRT) on the relationship between the cardiovascular and respiratory systems in heart failure subjects was examined for the first time. We hypothesized that alterations in cardio-respiratory interactions, after CRT implantation, quantified by signal complexity, could be a marker of a favorable CRT response. Sample entropy and scaling exponents were calculated from synchronously recorded cardiac and respiratory signals 20 min in duration, collected in 47 heart failure patients at rest, before and 9 months after CRT implantation. Further, cross-sample entropy between these signals was calculated. After CRT, all patients had lower heart rate and CRT responders had reduced breathing frequency. Results revealed that higher cardiac rhythm complexity in CRT non-responders was associated with weak correlations of cardiac rhythm at baseline measurement over long scales and over short scales at follow-up recording. Unlike CRT responders, in non-responders, a significant difference in respiratory rhythm complexity between measurements could be consequence of divergent changes in correlation properties of the respiratory signal over short and long scales. Asynchrony between cardiac and respiratory rhythm increased significantly in CRT non-responders during follow-up. Quantification of complexity and synchrony between cardiac and respiratory signals shows significant associations between CRT success and stability of cardio-respiratory coupling.

Tyrosine and Tryptophan vibrational bands as markers of kidney injury: a renocardiac syndrome induced by renal ischemia and reperfusion study

Renal injury caused by renal ischemia and reperfusion strongly influences heart morphology, electrophysiology, and redox unbalance. The so-called cardiorenal syndrome is an important class of dysfunction since heart and kidneys are responsible for hemodynamic stability and organ perfusion through a complex network. In the present work we investigate the vibrational spectral features probed by Fourier-Transform Raman (FT-Raman) spectroscopy due to physiological alterations induced by renal ischemic reperfusion aiming to detect molecular markers related to progression of acute to chronic kidney injury and mortality predictors as well. C57BL/6J mice were subjected to unilateral occlusion of the renal pedicle for 60 min and reperfusion for 5, 8, and 15 days. Biopsies of heart and kidney tissues were analyzed. Our findings indicated that cysteine/cystine, fatty acids, methyl groups of Collagen, α-form of proteins, Tyrosine, and Tryptophan were modulated during renal ischemia and reperfusion process. These changes are consistent with fibroblast growth factors and Collagen III contents changes. Interestingly, Tyrosine and Tryptophan, precursor molecules for the formation of uremic toxins such as indoxyl sulfate and p-cresyl sulfate were also modulated. They are markers of kidney injury and their increase is strongly correlated to cardiovascular mortality. Regarding this aspect, we notice that monitoring the Tyrosine and Tryptophan bands at 1558, 1616, and 1625 cm^-1 is a viable and and advantageous way to predict fatality in cardiovascular diseases both "in vivo" or "in vitro", using the real-time, multiplexing, and minimally invasive advantages of FT-Raman spectroscopy.

Fibrosis, the Bad Actor in Cardiorenal Syndromes: Mechanisms Involved

Cardiorenal syndrome is a term that defines the complex bidirectional nature of the interaction between cardiac and renal disease. It is well established that patients with kidney disease have higher incidence of cardiovascular comorbidities and that renal dysfunction is a significant threat to the prognosis of patients with cardiac disease. Fibrosis is a common characteristic of organ injury progression that has been proposed not only as a marker but also as an important driver of the pathophysiology of cardiorenal syndromes. Due to the relevance of fibrosis, its study might give insight into the mechanisms and targets that could potentially be modulated to prevent fibrosis development. The aim of this review was to summarize some of the pathophysiological pathways involved in the fibrotic damage seen in cardiorenal syndromes, such as inflammation, oxidative stress and endoplasmic reticulum stress, which are known to be triggers and mediators of fibrosis.

IGF IIRα-triggered pathological manifestations in the heart aggravate renal inflammation in STZ-induced type-I diabetes rats

Pathological manifestations in either heart or kidney impact the function of the other and form the basis for the development of cardiorenal syndrome. However, the mechanism or factors involved in such scenario are not completely elucidated. In our study, to find the correlation between late fetal gene expression in diabetic hearts and their influence on diabetic nephropathy, we created a rat model with cardiac specific overexpression of IGF-IIRα, which is an alternative splicing variant of IGFIIR, expressed in pathological hearts. In this study, transgenic rats over expressing cardiac specific IGF-IIRα and non-transgenic animal models established in SD rats were administered with single dose of streptozotocin (STZ, 55 mg/Kg) to induce Type I diabetes. The correlation between IGF-IIRα and kidney damages were further determined based on their intensity of damage in the kidneys. The results show that cardiac specific overexpression of IGF-IIRα elevates the diabetes associated inflammation and morphological changes in the kidneys. The diabetic transgenic rats showed advancement in the pathological features such a renal tubular damage, collagen accumulation and enhancement in STAT3 associated mechanism of renal fibrosis. The results therefore show that that IGF-IIRα expression in the heart during pathological condition may worsen symptoms of diabetic nephropathy in rats.

In Silico Integrative Approach Revealed Key MicroRNAs and Associated Target Genes in Cardiorenal Syndrome

Cardiorenal syndromes constellate primary dysfunction of either heart or kidney whereby one organ dysfunction leads to the dysfunction of another. The role of several microRNAs (miRNAs) has been implicated in number of diseases, including hypertension, heart failure, and kidney diseases. Wide range of miRNAs has been identified as ideal candidate biomarkers due to their stable expression. Current study was aimed to identify crucial miRNAs and their target genes associated with cardiorenal syndrome and to explore their interaction analysis. Three differentially expressed microRNAs (DEMs), namely, hsa-miR-4476, hsa-miR-345-3p, and hsa-miR-371a-5p, were obtained from GSE89699 and GSE87885 microRNA data sets, using R/GEO2R tools. Furthermore, literature mining resulted in the retrieval of 15 miRNAs from scientific research and review articles. The miRNAs-gene networks were constructed using miRNet (a Web platform of miRNA-centric network visual analytics). CytoHubba (Cytoscape plugin) was adopted to identify the modules and the top-ranked nodes in the network based on Degree centrality, Closeness centrality, Betweenness centrality, and Stress centrality. The overlapped miRNAs were further used in pathway enrichment analysis. We found that hsa-miR-21-5p was common in 8 pathways out of the top 10. Based on the degree, 5 miRNAs, namely, hsa-mir-122-5p, hsa-mir-222-3p, hsa-mir-21-5p, hsa-mir-146a-5p, and hsa-mir-29b-3p, are considered as key influencing nodes in a network. We suggest that the identified miRNAs and their target genes may have pathological relevance in cardiorenal syndrome (CRS) and may emerge as potential diagnostic biomarkers.

Impacts of Heart Failure and Physical Performance on Long-Term Mortality in Old Patients With Chronic Kidney Disease

Background: In patients with chronic kidney disease (CKD), physical functional limitations and heart failure (HF) are common, and each is associated with adverse outcomes. However, their joint effects on mortality are not clear.

Design and Methods: Using administration data from the geriatric department in a tertiary hospital, retrospective longitudinal analyses of patients aged ≥65 years with CKD were consecutively enrolled from February 2010 to November 2015. Baseline CKD stages, HF with reduced and preserved ejection fraction (HFrEF and HFpEF), Rockwood frailty index, handgrip strength (HGS), 6-m walking speed, and timed up-and-go test were used to predict the prevalence of frailty, physical disability, and all-cause mortality.

Results: Among 331 old patients with CKD, their mean age was 81.3 ± 6.6 years. CKD stages showed the following distributions: stage 3, 74.9%; stage 4, 15.7%; stage 5, 9.4%. The prevalence of HF was 23.3%, and Rockwood frailty was 74.3%. Rockwood frailty and HF were both significantly associated with CKD stages. After a mean follow-up period of 3.1 ± 2.1 years, 44 patients died, and a crude analysis showed that stage 4, stage 5 CKD, low HGS, and Rockwood frailty index were associated with mortality. Regarding the survival of these patients, the adjusted mortality hazard ratio for CKD stage 5 was 3.84 against stage 3A [95% confidence interval (CI) 1.51–9.75], 1.04 (95% CI 1.01–1.07) for higher Rockwood frailty score, 4.78 (95% CI 1.26–18.11) for HFrEF, and 3.47 (95% CI 1.15–10.42) for low HGS. Survival analysis using Kaplan–Meier survival plots showed that patients with both HF and poor HGS had the poorest survival.

Conclusions: Our study shows that both low physical performance and HF were common in old CKD patients and were associated with CKD stages. HF, frailty, and HGS all independently predicted the mortality of these CKD patients. The mortality is especially high amongst individuals with both HF and decreased HGS.

Uremic Toxins: An Alarming Danger Concerning the Cardiovascular System

The kidneys and heart share functions with the common goal of maintaining homeostasis. When kidney injury occurs, many compounds, the so-called "uremic retention solutes" or "uremic toxins," accumulate in the circulation targeting other tissues. The accumulation of uremic toxins such as p-cresyl sulfate, indoxyl sulfate and inorganic phosphate leads to a loss of a substantial number of body functions. Although the concept of uremic toxins is dated to the 1960s, the molecular mechanisms capable of leading to renal and cardiovascular injuries are not yet known. Besides, the greatest toxic effects appear to be induced by compounds that are difficult to remove by dialysis. Considering the close relationship between renal and cardiovascular functions, an understanding of the mechanisms involved in the production, clearance and overall impact of uremic toxins is extremely relevant for the understanding of pathologies of the cardiovascular system. Thus, the present study has as main focus to present an extensive review on the impact of uremic toxins in the cardiovascular system, bringing the state of the art on the subject as well as clinical implications related to patient's therapy affected by chronic kidney disease, which represents high mortality of patients with cardiac comorbidities.

AT1 receptor blocker, but not an ACE inhibitor, prevents kidneys from hypoperfusion during congestive heart failure in normotensive and hypertensive rats

To provide novel insights into the pathogenesis of heart failure-induced renal dysfunction, we compared the effects of ACE inhibitor (ACEi) and AT₁ receptor blocker (ARB) on systemic and kidney hemodynamics during heart failure in normotensive HanSD and hypertensive transgenic (TGR) rats. High-output heart failure was induced by creating an aorto-caval fistula (ACF). After five weeks, rats were either left untreated or treatment with ACEi or ARB was started for 15 weeks. Subsequently, echocardiographic, renal hemodynamic and biochemical measurements were assessed. Untreated ACF rats with ACF displayed significantly reduced renal blood flow (RBF) (HanSD: 8.9 ± 1.0 vs. 4.7 ± 1.6; TGR: 10.2 ± 1.9 vs. 5.9 ± 1.2 ml/min, both P < .001), ACEi had no major RBF effect, whereas ARB completely restored RBF (HanSD: 5.6 ± 1.1 vs. 9.0 ± 1.5; TGR: 7.0 ± 1.2 vs. 10.9 ± 1.9 ml/min, both P < .001). RBF reduction in untreated and ACEi-treated rats was accompanied by renal hypoxia as measured by renal lactate dehydrogenase activity, which was ameliorated with ARB treatment (HanSD: 40 ± 4 vs. 42 ± 3 vs. 29 ± 5; TGR: 88 ± 4 vs. 76 ± 4 vs. 58 ± 4 milliunits/mL, all P < .01). Unlike improvement seen in ARB-treated rats, ACE inhibition didn’t affect urinary nitrates compared to untreated ACF TGR rats (50 ± 14 vs. 22 ± 13 vs. 30 ± 13 μmol/mmol Cr, both P < .05). ARB was more effective than ACEi in reducing elevated renal oxidative stress following ACF placement. A marker of ACEi efficacy, the angiotensin I/angiotensin II ratio, was more than ten times lower in renal tissue than in plasma. Our study shows that ARB treatment, in contrast to ACEi administration, prevents renal hypoperfusion and hypoxia in ACF rats with concomitant improvement in NO bioavailability and oxidative stress reduction. The inability of ACE inhibition to improve renal hypoperfusion in ACF rats may result from incomplete intrarenal RAS suppression in the face of depleted compensatory mechanisms.

Fibroblast Growth Factor 23 and Left Ventricular Hypertrophy in Chronic Kidney Disease-A Pediatric Perspective

Cardiovascular diseases (CVD) are a hallmark in pediatric patients with chronic kidney disease (CKD) contributing to an enhanced risk of all-cause and CV morbidity and mortality in these patients. The bone-derived phosphaturic hormone fibroblast growth factor (FGF) 23 progressively rises with declining kidney function to maintain phosphate homeostasis, with up to 1,000-fold increase in patients with kidney failure requiring dialysis. FGF23 is associated with the development of left ventricular hypertrophy (LVH) and thereby accounts to be a CVD risk factor in CKD. Experimentally, FGF23 directly induces hypertrophic growth of cardiac myocytes in vitro and LVH in vivo. Further, clinical studies in adult CKD have observed cardiotoxicity associated with FGF23. Data regarding prevalence and determinants of FGF23 excess in children with CKD are limited. This review summarizes current data and discusses whether FGF23 may be a key driver of LVH in pediatric CKD.

H2S- and NO-releasing gasotransmitter platform: A crosstalk signaling pathway in the treatment of acute kidney injury

Acute kidney injury (AKI) is a syndrome affecting most patients hospitalized due to kidney disease; it accounts for 15 % of patients hospitalized in intensive care units worldwide. AKI is mainly caused by ischemia and reperfusion (IR) injury, which temporarily obstructs the blood flow, increases inflammation processes and induces oxidative stress. AKI treatments available nowadays present notable disadvantages, mostly for patients with other comorbidities. Thus, it is important to investigate different approaches to help minimizing side effects such as the ones observed in patients subjected to the aforementioned treatments. Therefore, the aim of the current review is to highlight the potential of two endogenous gasotransmitters - hydrogen sulfide (H₂S) and nitric oxide (NO) - and their crosstalk in AKI treatment. Both H₂S and NO are endogenous signalling molecules involved in several physiological and pathophysiological processes, such as the ones taking place in the renal system. Overall, these molecules act by decreasing inflammation, controlling reactive oxygen species (ROS) concentrations, activating/inactivating pro-inflammatory cytokines, as well as promoting vasodilation and decreasing apoptosis, hypertrophy and autophagy. Since these gasotransmitters are found in gaseous state at environmental conditions, they can be directly applied by inhalation, or in combination with H₂S and NO donors, which are compounds capable of releasing these molecules at biological conditions, thus enabling higher stability and slow release of NO and H₂S. Moreover, the combination between these donor compounds and nanomaterials has the potential to enable targeted treatments, reduce side effects and increase the potential of H₂S and NO. Finally, it is essential highlighting challenges to, and perspectives in, pharmacological applications of H₂S and NO to treat AKI, mainly in combination with nanoparticulated delivery platforms.

Panoramic Dominance of the Immune System in Cardiorenal Syndrome Type I

Physiological organ cross-talk is necessary to maintain equilibrium and homeostasis. Heart and kidney are the essences of this equilibrium. Organ failure in either of these organs can perturb the bidirectional communication between them, impinging this unpleasant vascular and cellular milieu on other distant organs. Cardiorenal syndrome (CRS) type I occurs due to acute deterioration of cardiac function, ultimately causing acute kidney injury (AKI). This syndrome is an intricate condition with neurohormonal and inflammatory aspects. Inflammation creates a vicious circle filled with the innate and adaptive immune systems, pro-inflammatory cytokines, chemokines to actuate hemodynamic compromise in CRS type I patients. Pro-inflammatory cytokines not only aggravate fluid retention and venous congestion but also initiate apoptosis and oxidative stress. The immune response's primary motive is to elicit the heart and kidney to produce cytokines, intensifying the inflammatory process. Despite the possible standard of care, patient mortality, treatment cost, readmissions are extreme in CRS type I, and inflammation certainly has critical inferences warranting future research in humans.

Prevalence, types, risk factors, and outcomes of cardiorenal syndrome in a rural population of central India: A cross-sectional study

Background and Objectives:

Heart failure leading to renal dysfunction and vice-versa termed as Cardio-Renal Syndrome(CRS) has now been increasingly identified as a marker of higher morbidity and mortality. Till date, there is limited data available regarding clinical profile, associated risk factors and outcome of CRS in rural population of central India. This study was conducted to elucidate the prevalence, risk factors, and outcome of CRS and its types.

Methods:

This was a single-centric, cross-sectional study conducted amongst the patients admitted to medicine wards and ICCU from October 2017 to September 2019. Classification given by RONCO et al. in 2008 was used for classifying CRS patients into various types. Cross-sectional data was used to find the prevalence, risk factors and their inter-relationship with outcome and mortality. STATA software was used for statistical analysis.

Results:

Out of 96 CRS patients, 47(48.96%) were Type 1, 22 (22.92%) were type 2, 19(19.79%) were type 4 and 3 (3.13% ) were type 3, and 5 (5.21%) were of type 5. Most common risk factor was Hypertension (HTN) found in 46 (47.92%), followed closely by Coronary Artery Disease (CAD) and anaemia. Mortality was seen in 44(45.83%) of CRS patients and it was significantly high. High mortality was common in patients of types 3 and type 5 CRS. Risk factors like HTN, CAD, smoking, reduced glomerular filtration rate, low ejection fraction and sepsis were significantly associated with worse outcomes across all CRS sub-types.

Interpretation and Conclusions:

There is high mortality among CRS. Prevention or optimal management of HTN, CAD and sepsis is required to decrease mortality. There is need for more population based studies for confirming our study findings.

Adaptive Autophagy Offers Cardiorenal Protection in Rats with Acute Myocardial Infarction

Objective

Understanding the multifactorial changes involved in the kidney and heart after acute myocardial infarction (AMI) is prerequisite for further mechanisms and early intervention, especially autophagy changes. Here, we discussed the role of adaptive autophagy in the heart and kidney of rats with AMI.

Methods

A rat model of AMI was established by ligating the left anterior descending branch of the coronary artery. Animals were sacrificed at 2 and 4 weeks after the operation to assess the morphological and functional changes of the heart and kidney, as well as the autophagy pathway. In vitro, HK-2 and AC16 cell injuries and the autophagy pathway were assayed after autophagy was inhibited by 3-methyladenine (3-MA) in a hypoxia incubator.

Results

We found that the left ventricular systolic pressure (LVSP) significantly decreased in the model group at weeks 2 and 4. At weeks 2 and 4, the level of urinary kidney injury molecule 1 (uKIM1) of the model group was significantly higher than the sham group. At week 4, urinary neutrophil gelatinase-associated lipocalcin (uNGAL) and urinary albumin also significantly increased. At week 2, microtubule-associated protein 1 light chain 3-II (LC3-II), ATG5, and Beclin1 were significantly elevated in the heart and kidney compared with the sham-operated rats, but there was no change in p62 levels. At week 4, LC3-II did not significantly increase and p62 levels significantly increased. In addition, 3-MA markedly increased KIM1, NGAL, and the activity of caspase-3 in the hypoxic HK-2 and AC16 cell.

Conclusion

Autophagy will undergo adaptive changes and play a protective role in the heart and kidney of rats after AMI.

An Overview of the Role of Calcium/Calmodulin-Dependent Protein Kinase in Cardiorenal Syndrome

Calcium/calmodulin-dependent protein kinases (CaMKs) are key regulators of calcium signaling in health and disease. CaMKII is the most abundant isoform in the heart; although classically described as a regulator of excitation–contraction coupling, recent studies show that it can also mediate inflammation in cardiovascular diseases (CVDs). Among CVDs, cardiorenal syndrome (CRS) represents a pressing issue to be addressed, considering the growing incidence of kidney diseases worldwide. In this review, we aimed to discuss the role of CaMK as an inflammatory mediator in heart and kidney interaction by conducting an extensive literature review using the database PubMed. Here, we summarize the role and regulating mechanisms of CaMKII present in several quality studies, providing a better understanding for future investigations of CamKII in CVDs. Surprisingly, despite the obvious importance of CaMKII in the heart, very little is known about CaMKII in CRS. In conclusion, more studies are necessary to further understand the role of CaMKII in CRS.

Cardiovascular Protection of Nephropathic Male Patients by Oral Food Supplements

Nephropathic patients show elevated cardiovascular morbidity and mortality compared to the general population. In order to delve deeper into the understanding of this phenomenon, it is necessary to recognize risk factors that are distinctive to the uremic state, such as oxidative stress and chronic low-grade inflammation. Moreover, gender differences have been reported in nephrology, as it has been observed that chronic kidney disease has higher prevalence in males than in females. The use of an oral food supplement (OFS) containing natural active compounds from Capsicum annuum L., Garcinia cambogia, Centella asiatica L., artichoke, and Aesculus hippocastanum L. which are virtually devoid from side effects, but rich in antioxidant and antiradical properties, could represent a valid therapeutic adjunct in the clinical management of nephropathic patients. Moreover, quantitative analysis performed in vitro on such compounds showed that they expressed good total antioxidant (7.28 gallic acid equivalents) and antiradical activity (above 80%). In this study, 23 male nephropathic patients and 10 age and body composition parameter matched healthy males (control group) were enrolled and took 3 cps/day of OFS for 5 weeks. At the end of the study, the nephropathic patient group showed a statistically significant reduction in the following laboratory parameters: total cholesterol (TC) (p = 0.044), atherogenic index TC/high-density lipoprotein cholesterol (p = 0.010), inflammatory parameters (C-reactive protein, p = 0.048, and erythrocyte sedimentation rate, p = 0.019), systolic (p = 0.044), and diastolic arterial blood pressure (p = 0.003). Regarding body composition, there was an increase in total body water % (p = 0.035) with redistribution of extracellular water % (p = 0.030) and intracellular water % (p = 0.049). In the control group, there was a reduction in fat mass % (p = 0.017) and extracellular water % (p = 0.047). Therefore, this OFS may represent a valid adjunct therapy to counteract comorbidities related to uremia.

A Mitochondrial Approach to Cardiovascular Risk and Disease

BACKGROUND

Cardiovascular diseases (CVDs) are a leading risk factor for mortality worldwide and the number of CVDs victims is predicted to rise through 2030. While several external parameters (genetic, behavioral, environmental and physiological) contribute to cardiovascular morbidity and mortality; intrinsic metabolic and functional determinants such as insulin resistance, hyperglycemia, inflammation, high blood pressure and dyslipidemia are considered to be dominant factors.

METHODS

Pubmed searches were performed using different keywords related with mitochondria and cardiovascular disease and risk. In vitro, animal and human results were extracted from the hits obtained.

RESULTS

High cardiac energy demand is sustained by mitochondrial ATP production, and abnormal mitochondrial function has been associated with several lifestyle- and aging-related pathologies in the developed world such as diabetes, non-alcoholic fatty liver disease (NAFLD) and kidney diseases, that in turn can lead to cardiac injury. In order to delay cardiac mitochondrial dysfunction in the context of cardiovascular risk, regular physical activity has been shown to improve mitochondrial parameters and myocardial tolerance to ischemia-reperfusion (IR). Furthermore, pharmacological interventions can prevent the risk of CVDs. Therapeutic agents that can target mitochondria, decreasing ROS production and improve its function have been intensively researched. One example is the mitochondria-targeted antioxidant MitoQ10, which already showed beneficial effects in hypertensive rat models. Carvedilol or antidiabetic drugs also showed protective effects by preventing cardiac mitochondrial oxidative damage.

CONCLUSION

This review highlights the role of mitochondrial dysfunction in CVDs, also show-casing several approaches that act by improving mitochondrial function in the heart, contributing to decrease some of the risk factors associated with CVDs.

Fabrication of low-fouling, high-loading polymeric surfaces through pH-controlled RAFT

Low-fouling and high-loading surfaces are increasingly important for biosensing and blood purification technologies. Selective and efficient target binding from complex media can be achieved with poly(carboxybetaine) (pCB) surfaces that consist of a dense brush layer to resist non-specific protein adsorption and a sparse “mushroom” upper layer for high-density capture agent immobilization (i.e. high-loading). We developed pH-controlled surface-reversible addition–fragmentation chain-transfer (S-RAFT) polymerization to simplify fabrication of multi-modal, low-fouling and high-loading pCB surfaces without the need for quenching or re-initiation steps, toxic transition metals or light irradiation. Multi-modal polymer layers were produced through partial polymer termination by temporarily raising the pH to aminolyse a fraction of dormant chain transfer agents (CTAs); remaining polymer chains with intact CTAs continued uninterrupted extension to create the “mushroom” upper layer. The multi-modal pCB surfaces were low-fouling towards proteins (<6.7 ng cm⁻²), and macrophages. Compared to mono-modal brush surfaces, multi-modal pCB surfaces were high-loading with 5-fold greater capture agent immobilization (e.g. antibody) and 4-fold greater target binding (e.g. biotin-fluorescein).

pH-Controlled surface-reversible addition–fragmentation chain-transfer (S-RAFT) polymerization yields a one-pot synthesis for bimodal polymeric surfaces for improved capture agent immobilization.