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In rats with unilateral nephrectomy and cardiac dysfunction, renal function deteriorates at an accelerated rate, as evidenced by increased proteinuria. Whether myocardial infarct-induced heart failure (HF) exacerbates renal injury in hypertensive rats with mild renal injury has not been reported. Rats underwent either coronary ligation or sham surgery. Thirty spontaneously hypertensive rats (SHRs) aged 8 weeks were randomly divided into two groups. Group 1 was the sham group, in which the rats underwent thoracotomy without ligation of the coronary artery. Group 2 underwent coronary artery ligation. The rats in group 2 underwent coronary artery ligation on week 0. The experiment lasted 12 weeks. Urine was collected in metabolic cages over a 24-h period. Urine was collected from the rats 2 days before the end of the experiment, and the ratio of urinary protein to urinary creatinine was measured in the clinical laboratory. All rats were examined by echocardiogram one day before the end of the experiment. On the last day of the experiment, blood was collected and sent to the laboratory for analysis. Hematoxylin-eosin (HE) and periodic acid-Schiff (PAS) staining were performed on heart and kidney sections. The ejection fraction in group 2 was lower than that in group 1 (P < 0.001). The urinary albumin to creatinine ratio in group 2 was greater than that in group 1 (P < 0.001). The urea and creatinine levels in group 1 were significantly lower than those in group 2 (P < 0.01). The levels of brain natriuretic peptide (BNP), neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C were greater in the second group than in the first group (P < 0.05). The interleukin-1β (IL-1β) and interleukin-6 (IL-6) levels in group 2 were significantly greater than those in group 1 (P < 0.001). The malondialdehyde (MDA) levels in Group 2 were greater than those in Group 1 (P < 0.01). The glutathione peroxidase (GSH-Px) levels in Group 2 were lower than those in Group 1 (P < 0.05). The level of angiotensin II (AT-II) in group 1 was lower than that in group 2 (P < 0.001). Cardiac dysfunction secondary to myocardial infarction could induce cardiorenal interactions in SHRs. It could be interpreted by the activation of oxidative stress, changes in inflammation and alteration of renin-angiotensin-aldosterone system., (© 2024. The Author(s).)

Background: The maladaptive neurohormonal activation, an integral mechanism in the pathophysiology of heart failure (HF) and cardiorenal syndrome, has a profound impact on renal sodium handling. Congestion is the primary reason for hospitalization of patients with HF and the main target of therapy. As sodium is the main determinant of extracellular volume, the goal is to enhance urinary sodium excretion in order to address excess fluid. The interventions to increase natriuresis have conventionally focused on distal nephron as the primary segment that counterbalances the effects of loop diuretics., Summary: Recent developments in the field of cardiorenal medicine have resulted in a shift of attention to renal proximal tubules (e.g., emerging evidence on proximal tubular dysfunction beyond handling of sodium). Herein, we discuss the three main mechanisms of sodium transport in the proximal tubules with emphasis on their intrinsic links to one another as well as to more distal transporters of sodium. Then, we provide an overview of the findings of the most recent clinical studies that have tried to enhance the conventional decongestive strategies through simultaneous blockade of these mechanisms., Key Message: Interventions aiming at renal proximal tubules have the potential to significantly improve our ability to decongest patients with acute HF., (© 2024 The Author(s). Published by S. Karger AG, Basel.)

Chronic kidney disease (CKD) and cardiovascular disease frequently run in parallel. Herein, Soppert et al. provide an interesting meta-analysis of the effects of CKD on cardiac remodeling and/or function in mice based on the model, strain, and duration. The authors sought to determine the most appropriate experimental model to unravel the specific underlying pathologic mechanisms involved in cardiac damage in CKD (single hit) or to investigate new strategies to prevent CKD-induced cardiovascular disease (multifactorial hits representing cardiovascular comorbidities of patients with CKD)., (Copyright © 2021 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

This study tested the hypothesis that Entresto (En) therapy protected the cardiomyocytes and heart function in cardiorenal syndrome (CRS) rats fed with high-protein diet (HPD) through regulating the oxidative-stress and Mfn2-mediated mitochondrial functional integrity. En (12.5 μM for the in-vitro study) protected the H9C2-cells against H 2 O 2 -induced cell apoptosis, whereas stepwise-increased H 2 O 2 concentrations induced a significant increase in protein expressions of Mfn2/phosphorylated (p)-DRP1/mitochondrial-Bax in H9C2-cells. En downregulated H 2 O 2 -induced mitochondrial fission/upregulated mitochondrial fusion and deletion of Mfn2 gene (i.e., shMfn2) to significantly reduce H 2 O 2 -induced ROS production. En significantly suppressed and shMfn2 further significantly suppressed both H 2 O 2 -reduced mitochondrial-membrane potential and H 2 O 2 -induced ROS production/cell apoptosis/mitochondrial damage/mitochondrial-Bax released from mitochondria in H9C2 cells. En significantly reduced protein expressions of Mfn2 and p-DRP1. Additionally, En significantly suppressed and shMfn2 further significantly suppressed the protein expressions of mitochondrial-damaged (DRP1)/oxidative-stress (NOX-1/NOX-2)/apoptosis (mitochondrial-Bax/caspase-3/PARP)/autophagic (LC3B-II/LC3B-I) biomarkers (all p < 0.01). Rats were categorized into group 1 [sham-control + high-protein-diet (HPD)], group 2 (CRS + HPD) and group 3 (CRS+ HPD + En/100 mg/kg/day). By day 63 after CRS induction, the LVEF was significantly lower in group 3 and more significantly lower in group 2 than in group 1, whereas the protein expressions of oxidative-stress (NOX-1/NOX-2/p22phox/oxidized protein)/apoptotic (mitochondrial-Bax/caspase-3/PARP), fibrotic (Smad-3/TGF-ß), autophagic (Beclin-1/Atg5/ratio of LC3B-II/LC3B-I) and mitochondrial-damaged (DRP1/cyclophilin-D/cytosolic-cytochrome-C) biomarkers exhibited an opposite pattern of LVEF among the groups. Downregulation of Mfn2 by En or shMfn2 in cardiomyocytes avoided H 2 O 2 damage and En improved the cardiac function in HPD-feeding CRS rat via adjusting Mfn2-mediated mitochondrial functional integrity., (Copyright © 2021 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Chronic kidney disease (CKD) is a major contributor to the development of heart failure with preserved ejection fraction (HFpEF), whereas the underlying mechanism of cardiorenal HFpEF is still elusive. The aim of this study was to investigate the role of cardiac fibrosis in a rat model of cardiorenal HFpEF and explore whether treatment with Telmisartan, an inhibitor of renin-angiotensin-aldosterone system (RAAS), can ameliorate cardiac fibrosis and preserve diastolic function in cardiorenal HFpEF. Male rats were subjected to 5/6 subtotal nephrectomy (SNX) or sham operation (Sham), and rats were allowed four weeks to recover and form a stable condition of CKD. Telmisartan or vehicle was then administered p.o. (8 mg/kg/d) for 12 weeks. Blood pressure, brain natriuretic peptide (BNP), echocardiography, and cardiac magnetic resonance imaging were acquired to evaluate cardiac structural and functional alterations. Histopathological staining, real-time polymerase chain reaction (PCR) and western blot were performed to evaluate cardiac remodeling. SNX rats showed an HFpEF phenotype with increased BNP, decreased early to late diastolic transmitral flow velocity (E/A) ratio, increased left ventricular (LV) hypertrophy and preserved ejection fraction (EF). Pathology revealed increased cardiac fibrosis in cardiorenal HFpEF rats compared with the Sham group, while chronic treatment with Telmisartan significantly decreased cardiac fibrosis, accompanied by reduced markers of fibrosis (collagen I and collagen III) and profibrotic cytokines (α-smooth muscle actin, transforming growth factor-β1, and connective tissue growth factor). In addition, myocardial inflammation was decreased after Telmisartan treatment, which was in a linear correlation with cardiac fibrosis. Telmisartan also reversed LV hypertrophy and E/A ratio, indicating that Telmisartan can improve LV remodeling and diastolic function in cardiorenal HFpEF. In conclusion, cardiac fibrosis is central to the pathology of cardiorenal HFpEF, and RAAS modulation with Telmisartan is capable of alleviating cardiac fibrosis and preserving diastolic dysfunction in this rat model.

Cardiorenal syndrome (CRS) is a pathological link between the kidneys and heart, in which an insult in a kidney or heart leads the other organ to incur damage. CRS is classified into five subtypes, and type 3 (CRS3) is characterized by acute kidney injury as a precursor to subsequent cardiovascular changes. Mitochondrial dysfunction and oxidative and nitrosative stress have been reported in the pathophysiology of CRS3. It is known that vitamin C, an antioxidant, has proven protective capacity for cardiac, renal, and vascular endothelial tissues. Therefore, the present study aimed to assess whether vitamin C provides protection to heart and the kidneys in an in vivo CRS3 model. The unilateral renal ischemia and reperfusion (IR) protocol was performed for 60 min in the left kidney of adult mice, with and without vitamin C treatment, immediately after IR or 15 days after IR. Kidneys and hearts were subsequently collected, and the following analyses were conducted: renal morphometric evaluation, serum urea and creatinine levels, high-resolution respirometry, amperometry technique for NO measurement, gene expression of mitochondrial dynamic markers, and NOS. The analyses showed that the left kidney weight was reduced, urea and creatinine levels were increased, mitochondrial oxygen consumption was reduced, NO levels were elevated, and Mfn2 expression was reduced after 15 days of IR compared to the sham group. Oxygen consumption and NO levels in the heart were also reduced. The treatment with vitamin C preserved the left kidney weight, restored renal function, reduced NO levels, decreased iNOS expression, elevated constitutive NOS isoforms, and improved oxygen consumption. In the heart, oxygen consumption and NO levels were improved after vitamin C treatment, whereas the three NOS isoforms were overexpressed. These data indicate that vitamin C provides protection to the kidneys and some beneficial effects to the heart after IR, indicating it may be a preventive approach against cardiorenal insults.

This study investigated the effect of apela on renal function and anti-inflammatory effect on whole body and kidney tissue in mice with type I cardiorenal syndrome (CRS). The murine type I CRS model was established and apela was subcutaneously infused for two weeks. Cardiac and renal functions were evaluated by echocardiography and blood biochemistry, respectively. The systemic and renal inflammatory responses were examined with molecular biological and histological methods. Human renal glomerular endothelial cells (RGECs) were used to evaluate the adhesion effect of monocytes in vitro. Compared to mice from the control group (CRS + vehicle), the plasma levels of N-terminal pro-brain natriuretic peptide, blood urea nitrogen and creatinine were significantly decreased, while the mean left ventricular ejection fraction was increased in apela-treated CRS mice at the 4th week. The expression of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-α (TNF-α) in the circulation and kidney was decreased in apela-treated mice compared with control mice, and apela improved cardio-renal pathology in mice with type I CRS. Additionally, Apela significantly suppressed the expression of MCP-1, TNF-α, intercellular adhesion molecule-1 and vascular intercellular adhesion molecule-1 in RGECs induced by angiotensin II (Ang II), and inhibited the promoting effect of Ang II on the adhesion of THP-1 cells to RGECs. Western blot results showed that the expression of phosphorylated nuclear factor kappa B (phospho-NFκB) in CRS mice was increased, but the expression of phospho-NFκB was down-regulated after apela treatment. Furthermore, apela significantly inhibited the Ang II-mediated increase in phospho-NFκB expression in RGECs in vitro, but the administration of an apelin peptide jejunum receptor (APJ) inhibitor blocked the inhibitory effect of apela. This study revealed that apela improves cardiorenal function and reduces systemic and renal inflammatory response in type I CRS mice and the apela/APJ system may alleviate renal inflammatory responses by inhibiting the NFκB signalling pathway., (© 2021 The Authors. The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology.)

Aims: This study investigated the renal protective effects and mechanisms of angiotensin receptor-neprilysin inhibitor LCZ696 in mice with cardiorenal syndrome., Materials and Methods: Mice were divided into abdominal aortic ligation alone, or treatment with LCZ696 or valsartan, whilst those undergoing sham surgery served as controls. Rat proximal renal tubular epithelial cells from the NRK-52E line were treated with control solution, LCZ696 or valsartan, in the presence or absence of Ang II for 24 h., Key Findings: Compared to controls, abdominal aortic ligation significantly increased plasma NT-proBNP and urine neutrophil gelatinase-associated lipocalin (NGAL), which were associated with reduced renal length and velocity time integral on ultrasonography. Histology revealed wrinkling of the glomerular capillary wall and sclerosis of the glomerulus, dilatation of the Bowman's capsule, accompanied by diffuse renal tubular atrophy and fibrosis, accompanied by lower kidney index and higher percentage area of fibrosis. Increases in NGAL and decreased ANP protein and mRNA expression levels were observed. These abnormalities were significantly prevented by LCZ696 and to a lesser extent by valsartan. Cellular experiments demonstrated a central role of Ang II/transforming growth factor-β1/Smad2/3/connective tissue growth factor-dependent signaling leading to type IV collagen deposition. This upregulation was reversed by LCZ696 in a greater extent than valsartan treatment alone, accompanied by a significant improvement in NGAL., Significance: LCZ696 can reduce kidney injury to a level beyond valsartan therapy alone in mice with cardiorenal syndrome, which can be speculated by effects on epithelial-mesenchymal transition and fibrosis through downregulating the TGF-β1/Smad2/3/CTGF/Collagen IV pathway., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The cardiorenal syndrome (CRS) is defined as the confluence of heart-kidney dysfunction. This study investigates the molecular differences at the level of the urinary peptidome between CRS patients and controls and their association to disease pathophysiology. The urinary peptidome of CRS patients (n = 353) was matched for age and sex with controls (n = 356) at a 1:1 ratio. Changes in the CRS peptidome versus controls were identified after applying the Mann-Whitney test, followed by correction for multiple testing. Proteasix tool was applied to investigate predicted proteases involved in CRS-associated peptide generation. Overall, 559 differentially excreted urinary peptides were associated with CRS patients. Of these, 193 peptides were specifically found in CRS when comparing with heart failure and chronic kidney disease urinary peptide profiles. Proteasix predicted 18 proteases involved in > 1% of proteolytic cleavage events including multiple forms of MMPs, proprotein convertases, cathepsins and kallikrein 4. Forty-four percent of the cleavage events were produced by 3 proteases including MMP13, MMP9 and MMP2. Pathway enrichment analysis supported that ECM-related pathways, fibrosis and inflammation were represented. Collectively, our study describes the changes in urinary peptides of CRS patients and potential proteases involved in their generation, laying the basis for further validation., (© 2021. The Author(s).)

Background Cardiac fibrosis plays a crucial role in the pathogenesis of dilated cardiomyopathy (DCM). HE4 (human epididymis protein 4) is a secretory protein expressed in activated fibroblasts that exacerbates tissue fibrosis. In the present study, we investigated the clinical utility of HE4 measurement in patients with DCM and its pathophysiological role in preclinical experiments in vivo and in vitro. Methods and Results We measured serum HE4 levels of 87 patients with DCM. Endomyocardial biopsy expressed severe fibrosis only in the high HE4 group ( P <0.0001). Echocardiography showed that left ventricular end-diastolic diameter tends to decrease over time (58±7.3 to 51±6.6 mm; P <0.0001) in the low HE4 group (<59.65 pmol/L [median value]). HE4 was significantly associated with risk reduction of mortality and cardiovascular hospitalization in multivariate Cox model. In vivo, HE4 was highly expressed in kidney and lung tissue of mouse, and scarcely expressed in heart. In genetically induced DCM mouse model, HE4 expression increased in kidney but not in heart and lung. In vitro, supernatant from HE4-transfected human embryonic kidney 293T cells enhanced transdifferentiation of rat neonatal fibroblasts and increased expression of fibrosis-related genes, and this was accompanied by the activation of extracellular signal-regulated kinase signaling in cardiac fibroblasts. Treatment with an inhibitor of upstream signal of extracellular signal-regulated kinase or a neutralizing HE4 antibody canceled the profibrotic properties of HE4. Conclusions HE4 functions as a secretory factor, activating cardiac fibroblasts, thereby inducing cardiac interstitial fibrosis. HE4 could be a promising biomarker for assessing ongoing fibrosis and a novel therapeutic target in DCM. Registration URL: https://upload.umin.ac.jp/cgi-open-bin/ctr; Unique identifier: UMIN000043062.

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.

There is a complex relationship between cardiac and renal disease, often referred to as the cardiorenal syndrome. Heart failure adversely affects kidney function, and both acute and chronic kidney disease are associated with structural and functional changes to the myocardium. The pathological mechanisms and contributing interactions that surround this relationship remain poorly understood, limiting the opportunities for therapeutic intervention. The cytokine tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and its receptor, fibroblast growth factor-inducible 14 (Fn14), are abundantly expressed in injured kidneys and heart. The TWEAK-Fn14 axis promotes responses that drive tissue injury such as inflammation, proliferation, fibrosis, and apoptosis, while restraining the expression of tissue protective factors such as the anti-aging factor Klotho and the master regulator of mitochondrial biogenesis peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). High levels of TWEAK induce cardiac remodeling, and promote inflammation, tubular and podocyte injury and death, fibroblast proliferation, and, ultimately, renal fibrosis. Accordingly, targeting the TWEAK-Fn14 axis is protective in experimental kidney and heart disease. TWEAK has also emerged as a biomarker of kidney damage and cardiovascular outcomes and has been successfully targeted in clinical trials. In this review, we update our current knowledge of the roles of the TWEAK-Fn14 axis in cardiovascular and kidney disease and its potential contribution to the cardiorenal syndrome. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd., (© 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)

Cardiorenal syndrome (CRS) has a high mortality, but its pathogenesis remains elusive. Fibroblast growth factor 23 (FGF23) is increased in both renal dysfunction and cardiac dysfunction, and FGF receptor 4 (FGFR4) has been identified as a receptor for FGF23. Deficiency of FGF23 causes growth retardation and shortens the lifespan, but it is unclear whether excess FGF23 is detrimental in CRS. This study sought to investigate whether FGF23 plays an important role in CRS-induced renal fibrosis. A mouse model of CRS was created by surgical myocardial infarction for 12 weeks. CRS mice showed a significant increase of circulatory and renal FGF23 protein levels, as well as an upregulation of p-GSK, active-β-catenin, TGF-β, collagen I and vimentin, a downregulation of renal Klotho expression and induction of cardiorenal dysfunction and cardiorenal fibrosis. These changes were enhanced by cardiac overexpression of FGF23 and attenuated by FGF receptor blocker PD173074 or β-catenin blocker IGC001. In fibroblasts (NRK-49F), expression of FGFR4 rather than Klotho was detected. Recombinant FGF23 upregulated the expression of p-GSK, active-β-catenin, TGF-β, collagen I and vimentin proteins. These changes were attenuated by FGFR4 blockade with BLU9931 or β-catenin blockade with IGC001. We concluded that FGF23 promotes CRS-induced renal fibrosis mediated by partly activating FGFR4/β-catenin signaling pathway.

The cardiorenal syndrome relates to the detrimental interplay between the vascular system and the kidney. The uremic milieu induced by reduced kidney function alters the phenotype of vascular smooth muscle cells (VSMC) and promotes vascular calcification, a condition which is strongly linked to cardiovascular morbidity and mortality. Biological mechanisms involved include generation of reactive oxygen species, inflammation and accelerated senescence. A better understanding of the vasotoxic effects of uremic retention molecules may reveal novel avenues to reduce vascular calcification in CKD. The present review aims to present a state of the art on the role of uremic toxins in pathogenesis of vascular calcification. Evidence, so far, is fragmentary and limited with only a few uremic toxins being investigated, often by a single group of investigators. Experimental heterogeneity furthermore hampers comparison. There is a clear need for a concerted action harmonizing and standardizing experimental protocols and combining efforts of basic and clinical researchers to solve the complex puzzle of uremic vascular calcification.

Cardiorenal syndrome type 4 (CRS4) is a common complication of chronic kidney disease (CKD), but the pathogenic mechanisms remain elusive. Here we report that morphological and functional changes in myocardial mitochondria are observed in CKD mice, especially decreases in oxidative phosphorylation and fatty acid metabolism. High phosphate (HP), a hallmark of CKD, contributes to myocardial energy metabolism dysfunction by downregulating peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α). Furthermore, the transcriptional factor interferon regulatory factor 1 (IRF1) is revealed as the key molecule upregulated by HP through histone H3K9 acetylation, and responsible for the HP-mediated transcriptional inhibition of PGC1α by directly binding to its promoter region. Conversely, restoration of PGC1α expression or genetic knockdown of IRF1 significantly attenuates HP-induced alterations in vitro and in vivo. These findings demonstrate that IRF1-PGC1α axis-mediated myocardial energy metabolism remodeling plays a crucial role in the pathogenesis of CRS4.

The pathogenesis of cardiorenal syndrome (CRS) is very complex, and currently there is no effective treatment for CRS. Higenamine (HI) has been shown to improve cardiac function in rats with heart failure. However, the role of higenamine in CRS remains unknown. Here, in vitro, higenamine treatment markedly reduced neonatal rat cardiac fibroblast collagen synthesis and inhibited neonatal rat cardiac myocyte hypertrophy. In our study, a rat model of type 2 CRS was induced by left anterior descending coronary artery ligation combined with 5/6 subtotal nephrectomy (STNx). Higenamine treatment decreased serum creatinine (Scr), blood urea nitrogen, and brain natriuretic peptide levels and was capable of improving left ventricular remodeling and systolic function in CRS rats, accompanied with decreased expression of transforming growth factor-β1 (TGF-β1), α-smooth muscle actin (α-SMA) and collagen I (Col1A1). Moreover, higenamine significantly inhibited the protein expression of phosphorylated apoptosis signal-regulated kinase 1 (p-ASK1) and downstream mitogen-activated protein kinases (MAPK) (ERK, P38)/NF-κB in cardiorenal tissues of CRS rats and neonatal rat cardiac fibroblast/neonatal rat cardiac myocyte cells. Our study demonstrated that higenamine improved cardiorenal function in CRS rats and attenuated heart and kidney fibrosis possibly via targeting ASK1/MAPK (ERK, P38)/NF-κB signaling pathway. This finding extends our knowledge on the role of higenamine in cardiorenal fibrosis, providing a potential target to prevent the progression of CRS.

Cardiorenal syndrome type-3 (CRS-3) is characterized by acute cardiac injury induced by acute kidney injury. Here, we investigated the causes of CRS-3 by analyzing cardiac function after renal ischemia-reperfusion injury (IRI) using echocardiography and evaluation of pro-inflammatory markers, calcium balance, mitochondrial function, and cardiomyocyte death. Our results show that renal IRI reduces cardiac diastolic function associated with cardiomyocyte death and inflammatory responses. Renal IRI also disrupts cardiomyocyte energy metabolism, induces calcium overload, and impairs mitochondrial function, as evidenced by reduced mitochondrial membrane potential and increased mitochondrial fission. Further, renal IRI induces phosphorylation of inositol 1,4,5-trisphosphate receptor (IP3R) and expression of mitochondrial calcium uniporter (MCU), resulting in cytoplasmic calcium overload and mitochondrial calcium accumulation. Pretreatment with melatonin attenuates renal IRI-mediated cardiac damage by maintaining myocardial diastolic function and reducing cardiomyocyte death. Melatonin also inhibits IP3R phosphorylation and MCU expression, thereby alleviating cytoplasmic and mitochondrial calcium overload. Blockade of IP3R has similar cardioprotective effects, whereas MCU activation abrogates the melatonin-mediated cardioprotection. These results show that the negative effects of renal IRI on myocardial viability and cardiac function are caused by induced IP3R phosphorylation, MCU upregulation, and calcium overload. Melatonin protects cardiac function against CRS-3 by suppressing IP3R-MCU signaling., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Cardiac remodeling occurs frequently in chronic kidney disease patients and affects quality of life and survival. Current treatment options are highly inadequate. As kidney function declines, numerous metabolic pathways are disturbed. Kidney and heart functions are highly connected by organ crosstalk. Among others, altered volume and pressure status, ischemia, accelerated atherosclerosis and arteriosclerosis, disturbed mineral metabolism, renal anemia, activation of the renin-angiotensin system, uremic toxins, oxidative stress and upregulation of cytokines stress the sensitive interplay between different cardiac cell types. The fatal consequences are left-ventricular hypertrophy, fibrosis and capillary rarefaction, which lead to systolic and/or diastolic left-ventricular failure. Furthermore, fibrosis triggers electric instability and sudden cardiac death. This review focuses on established and potential pathophysiological cardiorenal crosstalk mechanisms that drive uremia-induced senescence and disease progression, including potential known targets and animal models that might help us to better understand the disease and to identify novel therapeutics.

Background: Cardiorenal syndrome is a major cause of mortality in patients with chronic kidney disease (CKD). However, the involvement of detrimental humoral mediators in the pathogenesis of cardiorenal syndrome is still controversial. Trimethylamine-N-oxide (TMAO), a hepatic metabolic product of trimethylamine generated from dietary phosphatidylcholine or carnitine derived by the gut microbiota, has been linked directly with progression of cardiovascular disease and renal dysfunction. Thus, targeting TMAO may be a novel strategy for the prevention of cardiovascular disease and chronic kidney disease., Methods: Linaclotide, a guanylate cyclase C agonist, was administered to adenine-induced renal failure (RF) mice and changes in renal function and levels of gut-derived uremic toxins, as well as the gut microbiota community, were analyzed using metabolomic and metagenomic methods to reveal its cardiorenal effect., Results: Linaclotide decreased the plasma levels of TMAO at a clinically used low dose of 10 μg/kg in the adenine-induced RF mouse model. At a high concentration of 100 μg/kg, linaclotide clearly improved renal function and reduced the levels of various uremic toxins. A reduction in TMAO levels following linaclotide treatment was also observed in a choline-fed pro-atherosclerotic model. Linaclotide ameliorated renal inflammation and fibrosis and cardiac fibrosis, as well as decreased the expression of collagen I, transforming growth factor-β, galectin-3 (Gal-3) and ST2 genes. Plasma levels of Gal-3 and ST2 were also reduced. Because exposure of cardiomyocytes to TMAO increased fibronectin expression, these data suggest that linaclotide reduced the levels of TMAO and various uremic toxins and may result in not only renal, but also cardiac, fibrosis. F4/80-positive macrophages were abundant in small intestinal crypts in RF mice, and this increased expression was decreased by linaclotide. Reduced colonic claudin-1 levels were also restored by linaclotide, suggesting that linaclotide ameliorated the 'leaky gut' in RF mice. Metagenomic analysis revealed that the microbial order Clostridiales could be responsible for the change in TMAO levels., Conclusion: Linaclotide reduced TMAO and uremic toxin levels and could be a powerful tool for the prevention and control of the cardiorenal syndrome by modification of the gut-cardio-renal axis., (© The Author(s) 2019. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.)

Acute cardiorenal syndrome is a common complication of acute cardiovascular disease. Studies of acute kidney injury (AKI) to chronic kidney disease (CKD) transition, including patients suffering acute cardiovascular disease, report high rates of CKD development. Therefore, acute cardiorenal syndrome associates with CKD, but no study has established causation. To define this we used a murine cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) model or sham procedure on male mice. CA was induced with potassium chloride while CPR consisted of chest compressions and epinephrine eight minutes later. Two weeks after AKI was induced by CA/CPR, the measured glomerular filtration rate (GFR) was not different from sham. However, after seven weeks the mice developed CKD, recapitulating clinical observations. One day, and one, two, and seven weeks after CA/CPR, the GFR was measured, and renal tissue sections were evaluated for various indices of injury and inflammation. One day after CA/CPR, acute cardiorenal syndrome was indicated by a significant reduction of the mean GFR (649 in sham, vs. 25 μL/min/100g in CA/CPR animals), KIM-1 positive tubules, and acute tubular necrosis. Renal inflammation developed, with F4/80 positive and CD3-positive cells infiltrating the kidney one day and one week after CA/CPR, respectively. Although there was functional recovery with normalization of GFR two weeks after CA/CPR, deposition of tubulointerstitial matrix proteins α-smooth muscle actin and fibrillin-1 progressed, along with a significantly reduced mean GFR (623 in sham vs. 409 μL/min/100g in CA/CPR animals), proteinuria, increased tissue transforming growth factor-β, and fibrosis establishing the development of CKD seven weeks after CA/CPR. Thus, murine CA/CPR, a model of acute cardiorenal syndrome, causes an AKI-CKD transition likely due to prolonged renal inflammation., (Copyright © 2019 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Cardiorenal syndrome (CRS) remains a global health burden with a lack of definitive and effective treatment. Protein-bound uremic toxin (PBUT) overload has been identified as a non-traditional risk factor for cardiac, renal and vascular dysfunction due to significant albumin-binding properties, rendering these solutes non-dialyzable upon the state of irreversible kidney dysfunction. Although limited, experimental studies have investigated possible mechanisms in PBUT-mediated cardiac, renal and vascular effects. The ultimate aim is to identify relevant and efficacious targets that may translate beneficial outcomes in disease models and eventually in the clinic. This review will expand on detailed knowledge on mechanisms involved in detrimental effects of PBUT, specifically affecting the heart, kidney and vasculature, and explore potential effective intracellular targets to abolish their effects in CRS initiation and/or progression., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background and Aims: Klotho is an aging-suppressor gene mainly expressed in the renal tubules. The klotho gene encodes the α -klotho protein, which has many functions. Previous studies have found that α -klotho protein has a cardiorenal protective function. α -Klotho deficiency renders the kidney more susceptible to injury and results in cardiovascular calcification and left ventricular hypertrophy in chronic kidney disease. However, the role of α -klotho in acute heart injury and acute kidney injury with sepsis remains unknown. This study aimed to investigate the effects and mechanisms of α -klotho in septic cardiorenal injury., Methods: Male 8-week-old C57BL/6 mice were randomly assigned to the control group, lipopolysaccharide (LPS; 10 mg/kg) group, LPS (10 mg/kg)+ α -klotho (0.01 mg/kg) group, and LPS (10 mg/kg)+ α -klotho (0.02 mg/kg) group. Recombinant α -klotho was intraperitoneally injected an hour before LPS injection. Mice were euthanized at 24 h after LPS injection. The serum troponin, brain natriuretic peptide (BNP), neutrophil gelatinase-associated lipocalin (NGAL), and creatinine levels were measured in all groups at 24 h. Biomarkers of mice heart apoptosis, inflammation, oxidative stress, and endoplasmic reticulum stress, such as caspase-3, interleukin 1 (IL-1), reactive oxygen species (ROS), and glucose-regulated protein 78 (GRP78), were also measured., Results: α -Klotho was mainly expressed in mice kidneys and was undetectable in the control mice hearts. α -Klotho substantially decreased after LPS injection. In the LPS group, the serum troponin levels significantly increased as early as 6 h ( p < 0.05) after LPS injection, while the BNP, NGAL, and creatinine levels significantly increased at 24 h ( p < 0.05). Pretreatment with α -klotho significantly ameliorated acute cardiorenal injury. In the LPS+ α -klotho (0.01 mg/kg) group, the levels of apoptosis, inflammation, and oxidative stress were decreased, while the level of endoplasmic reticulum stress was elevated., Conclusions: α -Klotho significantly alleviates acute cardiorenal injury in LPS-induced septic cardiorenal injury due to the inhibition of apoptosis, inflammation, and oxidation, as well as the regulation of endoplasmic reticulum stress levels.

Aims: The mechanisms underlying cardiorenal syndromes are complex and not fully understood; Fibrosis seems to be a primary driver of the diseases' pathophysiology. Spironolactone can reduce cardiac or renal fibrosis by inhibiting endothelial-mesenchymal transition (EndMT). Spironolactone protection may rely on activation of adenosine receptors, but the role of the adenosine A2A receptor (A2AR) is unclear. We hypothesize that spironolactone may modulate A2AR to suppress EndMT and reduce cardiorenal remodeling., Main Methods: A model of renal injury followed by heart failure was established by subcutaneous administration of isoprenaline (Iso) to rats. Assessment of cardiac and renal function, fibrosis, EndMT markers, adenosine and A2AR expression was performed. TGF-β was used to induce EndMT in primary human umbilical vein endothelial cells (HUVECs). Rats or cells were divided into four groups: those that treated with spironolactone alone or in combination with A2AR antagonist ZM241385 or neither, and compared to normal controls., Key Findings: Isoprenaline-treated rats exhibited cardiac and renal fibrosis, impaired cardiac and renal function, enhanced EndMT, and lower A2AR expression. Spironolactone significantly up-regulated A2AR expression and inhibited EndMT in vivo and in vitro. Moreover, spironolactone improved cardiorenal remodeling and reduced dysfunction. These changes were exacerbated by administration of ZM241385. Together, these findings show that spironolactone up-regulated A2AR to reduce EndMT and ameliorate cardiorenal fibrosis., Significance: The anti-fibrotic effects of spironolactone may partly depend on the up-regulation of A2AR, and that A2AR might be a potential therapeutic target for the treatment of cardiorenal syndrome., (Copyright © 2019. Published by Elsevier Inc.)

Cardiorenal syndrome is defined by primary heart failure conditions influencing or leading to renal injury or dysfunction. Dilated cardiomyopathy (DCM) is a major co-existing form of heart failure (HF) with renal diseases. Myocardin (MYOCD), a cardiac-specific co-activator of serum response factor (SRF), is increased in DCM porcine and patient cardiac tissues and plays a crucial role in the pathophysiology of DCM. Inhibiting the increased MYOCD has shown to be partially rescuing the DCM phenotype in porcine model. However, expression levels of MYOCD in the cardiac tissues of the cardiorenal syndromic patients and the effect of inhibiting MYOCD in a cardiorenal syndrome model remains to be explored. Here, we analyzed the expression levels of MYOCD in the DCM patients with and without renal diseases. We also explored, whether cardiac specific silencing of MYOCD expression could ameliorate the cardiac remodeling and improve cardiac function in a renal artery ligated rat model (RAL). We observed an increase in MYOCD levels in the endomyocardial biopsies of DCM patients associated with renal failure compared to DCM alone. Silencing of MYOCD in RAL rats by a cardiac homing peptide conjugated MYOCD siRNA resulted in attenuation of cardiac hypertrophy, fibrosis and restoration of the left ventricular functions. Our data suggest hyper-activation of MYOCD in the pathogenesis of the cardiorenal failure cases. Also, MYOCD silencing showed beneficial effects by rescuing cardiac hypertrophy, fibrosis, size and function in a cardiorenal rat model.

In type 2 cardiorenal syndrome, chronic heart failure is thought to cause or promote chronic kidney disease; however, the underlying mechanisms remain poorly understood. We investigated the role of Wnt signaling in heart and kidney injury in a mouse model of cardiac hypertrophy and heart failure induced by transverse aortic constriction (TAC). At 8 weeks after TAC, cardiac hypertrophy, inflammation, and fibrosis were prominent, and echocardiography confirmed impaired cardiac function. The cardiac lesions were accompanied by upregulation of multiple Wnt ligands and activation of β-catenin, as well as activation of the renin-angiotensin system (RAS). Wnt3a induced multiple components of the RAS in primary cardiomyocytes and cardiac fibroblasts in vitro. TAC also caused proteinuria and kidney fibrosis, accompanied by klotho depletion and β-catenin activation in the kidney. Pharmacologic blockade of β-catenin with a small molecule inhibitor or the RAS with losartan ameliorated cardiac injury, restored heart function, and mitigated the renal lesions. Serum from TAC mice was sufficient to activate β-catenin and trigger tubular cell injury in vitro, indicating a role for circulating factors. Multiple inflammatory cytokines were upregulated in the circulation of TAC mice, and tumor necrosis factor-α was able to inhibit klotho, induce β-catenin activation, and cause tubular cell injury in vitro. These studies identify Wnt/β-catenin signaling as a common pathogenic mediator of heart and kidney injury in type 2 cardiorenal syndrome after TAC. Targeting this pathway could be a promising therapeutic strategy to protect both organs in cardiorenal syndrome., (Copyright © 2019 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are commonly used to control pain, inflammation, and limit the cardinal signs of injury in humans. However, prolonged use of NSAIDs increases the risk of heart attack (myocardial infarction; MI) and the subsequent risk of heart and renal failure. The molecular and cellular mechanism of action for this adverse effect, particularly along the cardiorenal network, is incomplete. To define the mechanism, carprofen (CAP), an NSAID was administered at the dose of 5 mg/kg to C57BL/6 male mice for two weeks. After last dose of CAP treatment mice were subjected to permanent occlusion of coronary artery that induces irreversible cardiac remodeling while maintaining naive and MI-controls. After MI, cardiac pathology and dysfunction were confirmed, along with additional measurements of kidney function, histology, and injury markers, such as plasma creatinine. CAP treatment increased plasma creatinine levels and subsequently, myocardial structural disorganization increased. Kidney neutrophil gelatinase associated lipocalin (NGAL) and protein expression were increased post-MI. After two weeks CAP treatment, the expression of pyrogenic pro-inflammatory cytokines TNF-α and IL-1β was increased compared to non-CAP treated mice, indicative of amplified inflammatory response. There was also evidence that renal injury of both the post-CAP treatment controls and post-CAP MI were much greater than the non-CAP treated naïve controls, as serum creatinine and NGAL levels were elevated along with obvious structural impairment of the glomerulus. Therefore, CAP treatment tampers with the acute inflammatory response that promotes cardiorenal syndrome and non-resolving inflammation post-MI in acute heart failure., (Copyright © 2018 Elsevier Inc. All rights reserved.)

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/mm 2 ) and similar to controls (9.85 ± 2.1 cell/mm 2 ). 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., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Renal dysfunction is an established risk factor for cardiovascular disease, but early disease states in both organs are poorly studied., Objective: This cross-sectional population-based study aims to investigate if there is an early association between kidney function and echocardiographic markers of cardiac structure and diastolic function., Methods: The study population consisted of 1,504 individuals with no prior history of congestive heart failure or asymptomatic left ventricular ejection fraction ≤40% and an estimated glomerular filtration rate (eGFR) based on cystatin C >15 mL/min/1.73 m2. The participants were categorized according to eGFR ≥90, 75-89, 60-74, 45-59, 30-44, and 15-29 mL/min/1.73 m2. We evaluated associations between eGFR categories and echocardiographic findings specific to cardiac structure and diastolic function., Results: Associations between eGFR categories and echocardiographic findings were found for left atrium area/body surface area (p = 0.013) indicating structural changes, and peak early mitral valve velocity (A; p = 0.003), peak late atrial mitral valve velocity/peak systolic myocardial velocity at mitral annulus in the lateral wall (E/Élat; p = 0.002), É mean of lateral and septal wall/Á mean of lateral and septal wall (mean É/Á; p = 0.027) indicating diastolic dysfunction. Associations between E/Élat and mean É/Á and eGFR categories were already present in individuals with eGFR 45-60 mL/min/1.73 m2. In sex-specific analysis these associations were only significant among men., Conclusion: A significant association between mild to moderate impairment of renal function and echocardiographic markers of cardiac structure and diastolic function was observed, supporting the hypothesis that interaction between the kidney and heart exists even in the early stages of renal impairment., (© 2019 S. Karger AG, Basel.)

Cardiorenal syndrome describes an active inter-relationship between heart and renal malfunction. The notion of passive renal congestion because of heart dysfunction and the informative term "rein cardiaque" by the French pathologist Frédéric Justin Collet (1870-1966) that reiterates revolutionized physiological thinking based on autopsy findings will be briefly discussed here., (© 2019 S. Karger AG, Basel.)

New Findings: What is the central question of this study? The aim was to determine the renoprotective effects of serelaxin in the setting of chronic heart failure. What are the main findings and its importance? Our data indicate that serelaxin can reduce renal fibrosis and inflammation in experimental heart failure. Currently, there are no effective treatments to rescue renal function in heart failure patients, and our data suggest that serelaxin might have the potential to reduce renal fibrosis and inflammation in heart failure., Abstract: Serelaxin has been demonstrated to attenuate renal fibrosis and inflammation in cardiorenal disease. In the present study, we tested the hypothesis that serelaxin can prevent the decline in renal function in dilated cardiomyopathy (DCM) by targeting renal fibrosis and inflammation. Male transgenic mice with DCM (n = 16) and their wild-type littermates (WT; n = 20) were administered either vehicle or serelaxin (500 μg kg -1  day -1 ; subcutaneous minipumps; 8 weeks). Cardiac function was assessed via echocardiography before and during the eighth week of serelaxin treatment. Renal function and inflammation as well as cardiac and renal fibrosis were assessed at the end of the study. Serelaxin had minimal effect on cardiac function (P ≥ 0.99). Tubulointerstitial and glomerular fibrosis were ∼3-fold greater in vehicle-treated DCM mice compared with vehicle-treated WT mice (P ≤ 0.001). Renal mRNA expression of Tnfα and Il1α were ∼4- and ∼3-fold greater, respectively, in vehicle-treated DCM mice compared with vehicle-treated WT mice (P ≤ 0.05). Tubulointerstitial and glomerular fibrosis were 46 and 45% less, respectively, in serelaxin-treated DCM mice than in vehicle-treated DCM mice (P ≤ 0.01). Renal cortical mRNA expression of Tnfα and Il1α were 56 and 58% less, respectively, in the former group compared with the latter (P ≤ 0.05). The urinary albumin:creatinine ratio was ∼3-fold greater in vehicle-treated DCM mice compared with vehicle-treated WT mice (P = 0.02). The urinary albumin:creatinine ratio was not significantly different between vehicle-treated DCM mice and serelaxin-treated DCM mice (P = 0.38). These data suggest that serelaxin can attenuate renal fibrosis and inflammation and has the potential to exert renoprotective effects in DCM., (© 2018 The Authors. Experimental Physiology © 2018 The Physiological Society.)

Complications arising from a functional arteriovenous fistula (AVF) in successful kidney transplant recipients (KT) have been overlooked despite some reports of its deleterious effect on heart, lungs, and kidney allograft. As such, there is no consensus regarding management of AVF after renal transplantation. We report Cardio-Renal Syndrome Type 5 in kidney transplant recipients who presented with a clinical syndrome of shortness of breath, edematous state, kidney allograft dysfunction, and high pulmonary pressure 3-8 months after successful transplantation. Investigations showed this to be due to high flow functioning AVF (>2 L/min) behaving like a systemic shunt causing high output heart failure, along with pulmonary and venous hypertension. This led to allograft dysfunction of fluid homeostasis. Symptoms resolved with cessation or reduction of AVF flow. Right heart catheterization and echocardiographic features indicating the syndrome are discussed to help clinicians identify the entity and decide management strategy for these AVF., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

There is a consensus that cardiorenal syndromes (CRS) are defined as the disorders of heart and kidney where acute or chronic dysfunction in one organ may induce acute or chronic dysfunction in another. Patients with CRS have increased hospitalization and mortality rates, and thus their identification is of great implication. Biomarkers are not only predictive in heart failure or renal diseases, but also useful in identifying cardiac dysfunction in renal diseases and renal injury in heart failure. Thus, they may be applied in order to identify patients with CRS and even assess prognosis and guide therapy in these patients. However, studies on biomarkers have just begun in CRS. Future studies are essential to observe current biomarkers and find novel biomarkers in CRS so as to improve diagnosis, therapy, and prognosis of CRS.

Cardiovascular events are the leading cause of death in patients with chronic kidney disease (CKD), although the pathological mechanisms are poorly understood. Here we longitudinally characterized left ventricle pathology in a 5/6 nephrectomy rat model of CKD and identify novel molecular mediators. Next-generation sequencing of left ventricle mRNA and microRNA (miRNA) was performed at physiologically distinct points in disease progression, identifying alterations in genes in numerous immune, lipid metabolism, and inflammatory pathways, as well as several miRNAs. MiRNA miR-21-5p was increased in our dataset and has been reported to regulate many identified pathways. Suppression of miR-21-5p protected rats with 5/6 nephrectomy from developing left ventricle hypertrophy and improved left ventricle function. Next-generation mRNA sequencing revealed that miR-21-5p suppression altered gene expression in peroxisome proliferator-activated receptor alpha (PPARα) regulated pathways in the left ventricle. PPARα, a miR-21-5p target, is the primary PPAR isoform in the heart, importantly involved in regulating fatty acid metabolism. Therapeutic delivery of low-dose PPARα agonist (clofibrate) to rats with 5/6 nephrectomy improved cardiac function and prevented left ventricle dilation. Thus, comprehensive characterization of left ventricle molecular changes highlights the involvement of numerous signaling pathways not previously explored in CKD models and identified PPARα as a potential therapeutic target for CKD-related cardiac dysfunction., (Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Heart failure (HF) secondary to myocardial infarction (MI) is linked to kidney complications that comprise cellular, structural, functional, and survival indicators. However, HF research is focused on left ventricular (LV) pathology. Here, we determined comprehensive functional analysis of the LV using echocardiography in transition from acute heart failure (AHF) to progressive chronic heart failure (CHF) pathology and developed a histological compendium of the cardiosplenic and cardiorenal networks in pathological remodeling. In surgically induced MI using permanent coronary ligation, the LV dysfunction is pronounced, with myocardium necrosis, wall thinning, and 20-30% LV rupture events that indicated AHF and CHF pathological remodeling in C57BL/6 male mice (2-4 mo old, n = 50). Temporal LV function analysis indicated that fractional shortening and strain are reduced from day 1 to day 5 in AHF and sustained to advance to CHF from day 28 to day 56 compared with naïve control mice ( n = 6). During the transition of AHF ( day 1 to day 5) to advanced CHF ( day 28 to day 56), histological and cellular changes in the spleen were definite, with bimodal inflammatory responses in kidney inflammatory biomarkers. Likewise, there was a unidirectional, progressive, and irreversible deposition of compact collagen in the LV along with dynamic changes in the cardiosplenic and cardiorenal networks post-MI. The renal histology and injury markers suggested that cardiac injury triggers irreversible dysregulation that actively alters the cardiosplenic and cardiorenal networks. In summary, the novel strategies or pathways that modulate comprehensive cardiosplenic and cardiorenal networks in AHF and CHF would be effective approaches to study either cardiac repair or cardiac pathology. NEW & NOTEWORTHY The present compendium shows irreversible ventricular dysfunction as assessed by temporal echocardiography while histological and structural measurements of the spleen and kidney added a novel direction to study cardiosplenic and cardiorenal networks in heart failure pathology. Therefore, the consideration of systems biology and integrative approach is essential to develop novel treatments.

Background: To evaluate the clinical features and outcomes of acute cardiorenal syndrome type-5 in patients with severe sepsis and septic shock., Methods: Historical cohort study of all adult patients with severe sepsis and septic shock admitted to the intensive care units (ICU) at Mayo Clinic Rochester from January 1, 2007 through December 31, 2014. Patients with prior renal or cardiac dysfunction were excluded. Patients were divided into groups with and without cardiorenal syndrome type-5. Acute Kidney Injury (AKI) was defined by both serum creatinine and urine output criteria of the AKI Network and the cardiac injury was determined by troponin-T levels. Outcomes included in-hospital mortality, ICU and hospital length of stay, and one-year survival., Results: Of 602 patients meeting the study inclusion criteria, 430 (71.4%) met criteria for acute cardiorenal syndrome type-5. Patients with cardiorenal syndrome type-5 had higher severity of illness, greater vasopressor and mechanical ventilation use. Cardiorenal syndrome type-5 was associated higher unadjusted in-hospital mortality, ICU and hospital lengths of stay, and lower one-year survival. When adjusted for age, gender, severity of illness and mechanical ventilation, cardiorenal syndrome type-5 was independently associated with 1.7-times greater odds of in-hospital mortality (p = .03), but did not predict one-year survival (p = .06) compared to patients without cardiorenal syndrome., Conclusions: In sepsis, acute cardiorenal syndrome type-5 is associated with worse in-hospital mortality compared to patients without cardiorenal syndrome.

Background: Cardiorenal syndrome type 1 (CRS type 1) is characterized by a rapid worsening of cardiac function leading to acute kidney injury (AKI). Its pathophysiology is complex and not completely understood. In this study, we examined the role of apoptosis and the caspase pathways involved., Material and Methods: We enrolled 40 acute heart failure (AHF) patients, 11 of whom developed AKI characterizing CRS type 1. We exposed the human cell line U937 to plasma from the CRS type 1 and AHF groups and then we evaluated apoptotic activity by annexin-V evaluation, determination of caspase-3, -8 and -9 levels, and BAX, BAD, and FAS gene expression., Results: We observed significant upregulation of apoptosis in monocytes exposed to CRS type 1 plasma compared to AHF, with increased levels of caspase-3 (p < 0.01), caspase-9 (p < 0.01), and caspase-8 (p < 0.03) showing activation of both intrinsic and extrinsic pathways. Furthermore, monocytes exposed to CRS type 1 plasma had increased gene expression of BAX and BAD (intrinsic pathways) (p = 0.010 for both). Furthermore, strong significant correlations between the caspase-9 levels and BAD and BAX gene expression were observed (Spearman ρ = - 0.76, p = 0.011, and ρ = - 0.72, p = 0.011)., Conclusion: CRS type 1 induces dual apoptotic pathway activation in monocytes; the two pathways converged on caspase-3. Many factors may induce activation of both intrinsic and extrinsic apoptotic pathways in CRS type 1 patients, such as upregulation of proinflammatory cytokines and hypoxia/ischemia. Further investigations are necessary to corroborate the present findings, and to better understand the pathophysiological mechanism and consequent therapeutic and prognostic implications for CRS type 1., (© 2018 S. Karger AG, Basel.)

Background/aims: Increased endoplasmic reticulum (ER) stress contributes to development of cardiorenal syndrome (CRS), and Silent Information Regulator 1 (SIRT1), a class III histone deacetylase, may have protective effects on heart and renal disease, by reducing ER stress. We aimed to determine if SIRT1 alleviates CRS through ER stress reduction., Methods: Wild type mice (n=37), mice with cardiac-specific SIRT1 knockout (n=29), or overexpression (n=29), and corresponding controls, were randomized into four groups: sham MI (myocardial infarction) +sham STNx (subtotal nephrectomy); MI+sham STNx; sham MI+STNx; and MI+STNx. To establish the CRS model, subtotal nephrectomy (5/6 nephrectomy, SNTx) and myocardial infarction (MI) (induced by ligation of the left anterior descending (LAD) coronary artery) were performed successively to establish CRS model. At week 8, the mice were sacrificed after sequential echocardiographic and hemodynamic studies, and then pathology and Western-blot analysis were performed., Results: Neither MI nor STNx alone significantly influenced the other healthy organ. However, in MI groups, STNx led to more severe cardiac structural and functional deterioration, with increased remodeling, increased BNP levels, and decreased EF, Max +dp/dt, and Max -dp/dt values than in sham MI +STNx groups. Conversely, in STNx groups, MI led to renal structural and functional deterioration, with more severe morphologic changes, augmented desmin and decreased nephrin expression, and increased BUN, SCr and UCAR levels. In MI+STNx groups, SIRT1 knockout led to more severe cardiac structural and functional deterioration, with higher Masson-staining score and BNP levels, and lower EF, FS, Max +dp/dt, and Max -dp/dt values; while SIRT1 overexpression had the opposite attenuating effects. In kidney, SIRT1 knockout resulted in greater structural and functional deterioration, as evidenced by more severe morphologic changes, higher levels of UACR, BUN and SCr, and increased desmin and TGF-β expression, while SIRT1 overexpression resulted in less severe morphologic changes and increased nephrin expression without significant influence on BUN or SCr levels. The SIRT1 knockout but not overexpression resulted in increased myocardial expression of CHOP and GRP78. Cardiac-specific SIRT1 knockout or overexpression resulted in increased or decreased renal expression of CHOP, Bax, and p53 respectively., Conclusions: Myocardial SIRT1 activation appears protective to both heart and kidney in CRS models, probably through modulation of ER stress., (© 2018 The Author(s). Published by S. Karger AG, Basel.)

Intracellular accumulation of protein-bound uremic toxins in the setting of cardiorenal syndrome leads to adverse effects on cardiorenal cellular functions, where cardiac hypertrophy and cardiorenal fibrosis are the hallmarks. In this study, we sought to determine if Apoptosis Signal-Regulated Kinase 1 (ASK1), an upstream regulator of cellular stress response, mediates cardiac hypertrophy and cardiorenal fibrosis induced by indoxyl sulfate (IS) and p-cresol sulfate (PCS) in vitro, and whether ASK1 inhibition is beneficial to ameliorate these cellular effects. PCS augmented cardiac myocyte hypertrophy and fibroblast collagen synthesis (as determined by 3H-leucine and 3H-proline incorporation, respectively), similar to our previous finding with IS. IS and PCS also increased collagen synthesis of proximal tubular cells and renal mesangial cells. Pro-hypertrophic (α-skeletal muscle actin and β-MHC) and pro-fibrotic genes (TGF-β1 and ctgf) were induced by both IS and PCS. Western blot analyses revealed the activation of ASK1 and downstream mitogen activated protein kinases (MAPKs) (p38MAPK and ERK1/2) as well as nuclear factor-kappa B (NF-κB) by IS and PCS. ASK1, OAT1/3, ERK1/2 and p38MAPK inhibitors suppressed all these effects. In summary, IS and PCS exhibit pro-hypertrophic and pro-fibrotic properties, at least in part, via the activation of ASK1 and its downstream pathways. ASK1 inhibitor is an effective therapeutic agent to alleviate protein-bound uremic toxin-induced cardiac hypertrophy and cardiorenal fibrosis in vitro, and may be translated further for cardiorenal syndrome therapy.

The early events that signal renal dysfunction in presymptomatic heart failure are unclear. We tested the hypothesis that functional and mechanistic changes occur in the kidney that precede the development of symptomatic heart failure. We employed a transgenic mouse model with cardiomyocyte-specific overexpression of mutant α-B-crystallin that develops slowly progressive cardiomyopathy. Presymptomatic transgenic mice displayed an increase in serum creatinine (1.17 ± 0.34 vs. wild type 0.65 ± 0.16 mg/dl, P < 0.05) and in urinary neutrophil gelatinase-associated lipocalin (NGAL; 278.92 ± 176.24 vs. wild type 49.11 ± 22.79 ng/ml, P < 0.05) but no renal fibrosis. Presymptomatic transgenic mouse kidneys exhibited a twofold upregulation of the Ren1 gene, marked overexpression of renin protein in the tubules, and a worsened response to ischemia-reperfusion injury based on serum creatinine (2.77 ± 0.66 in transgenic mice vs. 2.01 ± 0.58 mg/dl in wild type, P < 0.05), urine NGAL (9,198.79 ± 3,799.52 in transgenic mice vs. 3,252.94 ± 2,420.36 ng/ml in wild type, P < 0.05), tubule dilation score (3.4 ± 0.5 in transgenic mice vs. 2.6 ± 0.5 in wild type, P < 0.05), tubule cast score (3.2 ± 0.4 in transgenic mice vs. 2.5 ± 0.5 in wild type, P < 0.05), and TdT-mediated dUTP nick-end labeling (TUNEL)-positive nuclei (10.1 ± 2.1 in the transgenic group vs. 5.7 ± 1.6 per 100 cells counted in wild type, P < 0.01). Our findings indicate functional renal impairment, urinary biomarker elevations, and induction of renin gene and protein expression in the kidney that occur in early presymptomatic heart failure, which increase the susceptibility to subsequent acute kidney injury., (Copyright © 2017 the American Physiological Society.)

The pathologic crosstalk between the heart and kidney is known as cardiorenal syndrome (CRS). While the specific mechanisms underlying this crosstalk remain poorly understood, CRS is associated with exacerbated dysfunction of either or both organs and reduced survival. Maladaptive fibrotic remodeling is a key component of both heart and kidney failure pathogenesis and progression. G-protein coupled receptor (GPCR) signaling is a crucial regulator of cardiovascular and renal function. Chronic/pathologic GPCR signaling elicits the interaction of the G-protein Gβγ subunit with GPCR kinase 2 (GRK2), targeting the receptor for internalization, scaffolding to pathologic signals, and receptor degradation. Targeting this pathologic Gβγ-GRK2 interaction has been suggested as a possible strategy for the treatment of HF. In the current review, we discuss recent updates in understanding the role of GPCR-Gβγ-GRK2 signaling as a crucial mediator of maladaptive organ remodeling detected in HF and kidney dysfunction, with specific attention to small molecule-mediated inhibition of pathologic Gβγ-GRK2 interactions. Further, we explore the potential of GPCR-Gβγ-GRK2 signaling as a possible therapeutic target for cardiorenal pathologies., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Cardiorenal syndrome type 1 causes acute kidney injury but is poorly understood; animal models and diagnostic aids are lacking. Robust noninvasive measurements of glomerular filtration rate are required for injury models and clinical use. Several have been described but are untested in translational models and suffer from biologic interference. We developed a mouse model of cardiorenal syndrome and tested the novel near-infrared fluorophore ZW800-1 to assess renal and cardiac function. We performed murine cardiac arrest and cardiopulmonary resuscitation followed by transthoracic echocardiography, 2 and 24 h later. Transcutaneous fluorescence of ZW800-1 bolus dispersion and clearance was assessed with whole animal imaging and compared with glomerular filtration rate (GFR; inulin clearance), tubular cell death (using unbiased stereology), and serum creatinine. Correlation, Bland-Altman, and polar analyses were used to compare GFR with ZW800-1 clearance. Cardiac arrest and cardiopulmonary resuscitation caused reversible cardiac failure, halving fractional shortening of the left ventricle ( n = 12, P = 0.03). Acute kidney injury resulted with near-zero GFR and sixfold increase in serum creatinine 24 h later ( n = 16, P < 0.01). ZW800-1 biodistribution and clearance were exclusively renal. ZW800-1 t 1/2 and clearance correlated with GFR ( r = 0.92, n = 31, P < 0.0001). ZW800-1 fluorescence was reduced in cardiac arrest, and cardiopulmonary resuscitation-treated mice compared with sham animals 810 s after injection ( P < 0.01) and bolus time-dispersion curves demonstrated that ZW800-1 fluorescence dispersion correlated with left ventricular function ( r = 0.74, P < 0.01). Cardiac arrest and cardiopulmonary resuscitation lead to experimental cardiorenal syndrome type 1. ZW800-1, a small near-infrared fluorophore being developed for clinical intraoperative imaging, is favorable for evaluating cardiac and renal function noninvasively., (Copyright © 2017 the American Physiological Society.)

Gram-negative sepsis is a major cause of morbidity and mortality in critical ill patients. Recent findings in molecular biology and in signaling pathways have enhanced our understanding of its pathogenesis and opened up opportunities of innovative therapeutic approaches. Endotoxin plays a pivotal role in the pathogenesis of multi-organ dysfunction in the setting of gram-negative sepsis. Indeed, heart and kidney impairments seem to be induced by the release of circulating pro-inflammatory and pro-apoptotic mediators triggered by endotoxin interaction with immune cells. These molecules are responsible for cellular apoptosis, autophagy, cell cycle arrest, and microRNAs activation. Therefore, the early identification of sepsis-associated acute kidney injury and heart dysfunction may improve the patient clinical outcome. In this report, we will consider the role of endotoxin in the pathogenesis of sepsis, its effects on both cardiac and renal functions, and the interactions between these 2 systems in the setting of cardiorenal syndromes (CRS), particularly in CRS type 5. Finally, we will discuss the possible role of extracorporeal therapies in reducing endotoxin levels., (© 2017 S. Karger AG, Basel.)

Hypertension-associated end-organ damage commonly leads to cardiac and renal fibrosis. As no effective anti-fibrotic therapy currently exists, the unchecked progression of fibrogenesis manifests as cardio-renal failure and early death. We have previously shown that FATp300-p300 with intrinsic factor acetyltransferase activity-is an essential epigenetic regulator of fibrogenesis, and is elevated in several fibrotic tissues. In this report, we investigate the therapeutic efficacy of a novel FATp300 inhibitor, L002, in a murine model of hypertensive cardio-renal fibrosis. Additionally, we examine the effects of L002 on cellular pro-fibrogenic processes and provide mechanistic insights into its antifibrogenic action. Utilizing cardiac fibroblasts, podocytes, and mesangial cells, we demonstrate that L002 blunts FATp300-mediated acetylation of specific histones. Further, incubating cells with L002 suppresses several pro-fibrogenic processes including cellular proliferation, migration, myofibroblast differentiation and collagen synthesis. Importantly, systemic administration of L002 in mice reduces hypertension-associated pathological hypertrophy, cardiac fibrosis and renal fibrosis. The anti-hypertrophic and anti-fibrotic effects of L002 were independent of blood pressure regulation. Our work solidifies the role of epigenetic regulator FATp300 in fibrogenesis and establishes it as a pharmacological target for reducing pathological matrix remodeling and associated pathologies. Additionally, we discover a new therapeutic role of L002, as it ameliorates hypertension-induced cardio-renal fibrosis and antagonizes pro-fibrogenic responses in fibroblasts, podocytes and mesangial cells.

We investigated the cardioprotective effect of melatonin (Mel) and exendin-4 (Ex4) treatment in a rat model of cardiorenal syndrome (CRS). Adult male SD rats (n=48) were randomly and equally divided into sham control (SC), dilated cardiomyopathy (DCM) (doxorubicin 7 mg/kg i.p. every five days/4 doses), CRS (defined as DCM+CKD) only, CRS-Mel (20 mg/kg/d), CRS-Ex4 (10 μg/kg/d), and CRS-Mel-Ex4 groups. In vitro results showed protein expressions of oxidative stress (NOX-1/NOX-2/oxidized protein), DNA/mitochondrial damage (γ-H2AX/cytosolic cytochrome c), apoptosis (cleaved caspase-3/PARP), and senescence (β-galactosidase cells) biomarkers were upregulated, whereas mitochondrial ATP level was decreased in doxorubicin/p-cresol-treated H9c2 cells that were revised by Mel and Ex4 treatments (all P<.001). By day 60, LVEF was highest in the SC and lowest in the CRS, significantly lower in the DCM than in other treatment groups, lower in the CRS-Mel and CRS-Ex4 than in the CRS-Mel-Ex4, and lower in the CRS-Mel than in the CRS-Ex4, whereas LV chamber size and histopathology score showed a pattern opposite to that of LVEF among all groups (all P<.001). Plasma creatinine level was highest in the CRS and lowest in the SC and progressively decreased from the CRS-Mel, CRS-Ex4, CRS-Mel-Ex4 to DCM (P<.0001). Protein expressions of inflammation (TNF-α/NF-κB/MMP-2/MMP-9/IL-1β), apoptosis/DNA damage (Bax/c-caspase-3/c-PARP/γ-H2AX), fibrosis (Smad3/TGF-β), oxidative stress (NOX-1/NOX-2/NOX-4/oxidized protein), cardiac hypertrophy/pressure overload (BNP/β-MHC), and cardiac integrity (Cx43/α-MHC) biomarkers in LV myocardium showed an opposite pattern compared to that of LVEF among all groups (all P<.001). Fibrotic area, DNA damage (γ-H2AX + /53BP1 + CD90 + /XRCC1 + CD90 + ), and inflammation (CD14 + /CD68 + ) biomarkers in LV myocardium displayed a pattern opposite to that of LVEF among all groups (all P<.001). Combined melatonin and exendin-4 treatment suppressed CRS-induced deterioration of LVEF and LV remodeling., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Renal dysfunction and heart failure commonly co-exist; it is termed the cardiorenal syndrome (CRS). This combination of renal and cardiac impairment presents a substantial clinical challenge and is associated with adverse prognosis. The pathogenesis of the CRS is complex, including chronic activation of the renin-angiotensin-aldosterone system (RAAS) and the sympathetic nervous system, together with reduced renal perfusion. Chronic activation of the RAAS can impair mitochondrial function, and increase mitochondrial derived oxidative stress which in turn can lead to renal injury and sodium and water retention. For example, it has been shown that exogenous Ang II augments renal mitochondrial oxidative stress, reduces GFR and induces albuminuria in rats with heart failure. Administration of Ang II also augmented renal mitochondrial dysfunction in aged mice. Current treatments for CRS, including angiotensin-converting enzyme inhibitors, exert limited renal protection if any at all. Therefore, novel treatments particularly those that can target renal mechanisms downstream to chronic activation of the renal renin-angiotensin system are likely to exert renoprotection in the setting of CRS., (Copyright © 2016 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

The protective abilities of the chloroform extract of Ocimum gratissimum (COG) and gallic acid against cobalt chloride (CoCl2) - induced cardiac and renal toxicity were evaluated. Rats were exposed to CoCl2 (350ppm) for 7 days, either alone, or in combination with COG (100 and 200mg/kg) or gallic acid (120mg/kg). CoCl2 given alone, caused significant increases (p<0.05) in oxidative stress parameters (hydrogen peroxide, H2O2 and malondialdehyde, MDA) and increased expression of the apoptotic initiator caspase 8 in the heart and kidneys. There was significant reduction (p<0.05) in reduced glutathione (GSH) in cardiac and renal tissues; reduction in superoxide dismutase (SOD) activity in the kidneys and adaptive increases in Glutathione S-transferase (GST) and catalase (CAT). CoCl2 also produced significant reduction (p<0.05) in systolic (SBP), diastolic (DBP) and mean arterial (MAP) blood pressures. Oral COG and gallic acid treatment significantly reduced (p<0.05) the levels of H2O2 and MDA; with reduced expression of caspase 8 and restoration of GSH levels, GPx, SOD and CAT activities, howbeit, to varying degrees in the heart and kidneys. COG (200mg/kg) was most effective in restoring the blood pressures in the rats to near control levels. CoCl2-induced histopathological lesions including myocardial infarction and inflammation and renal tubular necrosis and inflammation were effectively ameliorated by the treatments administered. This study provides evidence for the protective roles of O. gratissimum and gallic acid by modulation of CoCl2-induced alterations in blood pressure, antioxidant status and pro-apoptotic caspase 8 in Wistar rats., (Copyright © 2016 Elsevier GmbH. All rights reserved.)

Background: Cardiorenal syndrome is a complicated and bidirectional interrelationship between the heart and kidneys. Naringenin (NG) is a naturally occurring flavonoid possessing various biological and pharmacological properties., Materials and Methods: We tested whether NG could improve cardiac and renal function in a rat model of cardiorenal syndrome., Results: The results showed that NG-attenuated cardiac remodeling and cardiac dysfunction in rats with cardiorenal syndrome, as evidenced by decrease of left ventricle weight (LVW), increase of body weight (BW), decrease of LVW/BW, decrease of concentrations of serum creatinine, blood urea nitrogen, type-B natriuretic peptide, aldosterone, angiotensin (Ang) II, C-reactive protein, and urine protein, increase of left ventricular systolic pressure and falling rates of left ventricular pressure (dp/dtmax), and decrease of left ventricular diastolic pressure, left ventricular end-diastolic pressure, and -dp/dtmax. NG significantly inhibited the increase of lipid profiles including low-density lipoprotein, TC, and TG in rats. In addition, NG significantly inhibited the increase of cardiac expression of IL-1β, IL-6, and interferon γ. Moreover, NG decreased malonaldehyde level, increased superoxide dismutase activity and glutathione content in rats, and increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and catalytic subunit of γ-glutamylcysteine ligase (GCLc) in rats and Ang II-treated cardiac fibroblasts. Inhibition of Nrf2 and glutathione synthesis significantly suppressed NG-induced decrease of ROS level. Inhibition of Nrf2 markedly suppressed NG-induced increase of GCLc expression in Ang II-treated cardiac fibroblasts., Conclusions: The data provide novel options for therapy of patients and new insights into the cardioprotective effects of NG in cardiorenal syndrome., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: Pathologic changes that are associated with the cardiorenal syndrome (CRS) are seldom described. The two theories that address renal physiology in CRS include chronic indolent ischemia from renal vasoconstriction and chronic glomerular venous congestion from increased venous pressures. We report on the glomerular histologic changes that occur with long standing heart failure., Objective: To examine whether CRS causes renal ischemia that manifests as glomerular size reduction., Methods: We performed a case-control study where we measured total glomerular areas in 16 adult cases with end-stage heart disease and compared them with matched controls. Control biopsy samples were obtained from renal tissue included in nephrectomies. Glomerular size was measured using the BioQuant Image Analysis program. Cases and controls were matched on the following variables: age (within 10 years), race, body mass index (BMI), diabetes mellitus (DM), glomerular filtration rate (GFR) (within 10 mL/min/1.73 m2), and history of tobacco use., Results: The age range of all patients at the time of biopsy was 40 - 73 years. Nine of the case patients had DM. Estimated GFR ranged from 29 to 55 mL/min/1.73 m2. Mean BMI was 30.8 (SD 4.7) kg/m2. The average median glomerular area in the case patients was 23,944 pixels (1 pixel = 1 μm2), (IQR 22,549 - 27,990) vs. in controls 38,566 pixels (IQR 31, 227 - 45,938) (p = 0.004)., Conclusions: This case-controlled cohort study demonstrates that patients with long standing heart failure have smaller glomerular size as compared with controls matched for relevant clinical variables but not for heart failure.

Cardiorenal syndrome involves disease and dysfunction of the heart that leads to progressive renal dysfunction. This study investigated the relationship between cardiac and renal disease in 91 aged chimpanzees at the Alamogordo Primate Facility by evaluation of the medical histories, metabolic parameters, functional measurements of the cardiovascular system, clinical pathology, and histopathology focused on the heart and kidney. Cardiac fibrosis was the most frequent microscopic finding in 82 of 91 animals (90%), followed by glomerulosclerosis with tubulointerstitial fibrosis in 63 of 91 (69%). Cardiac fibrosis with attendant glomerulosclerosis and tubulointerstitial fibrosis was observed in 58 of 91 animals (63%); there was a statistically significant association between the 2 conditions. As the severity of cardiac fibrosis increased, there was corresponding increase in severity of glomerulosclerosis with tubulointerstitial fibrosis. Altered metabolic, cardiovascular, and clinical pathology parameters indicative of heart and kidney failure were commonly associated with the moderate to severe microscopic changes, and concurrent heart and kidney failure were considered the cause of death. The constellation of findings in the chimpanzees were similar to cardiorenal syndrome in humans., (© The Author(s) 2016.)