The potential role of hydrogen sulfide in regulating macrophage phenotypic changes via PINK1/parkin-mediated mitophagy in sepsis-related cardiorenal syndrome

OBJECTIVE

Sepsis is one of major reasons of cardiorenal syndrome type 5 (CRS-5), resulting in irreversible tissue damage and organ dysfunction. Macrophage has been demonstrated to play key role in the pathophysiology of sepsis, highlighting the need to identify therapeutic targets for modulating macrophage phenotype in sepsis.

METHODS AND RESULTS

In this study, a rapid-releasing hydrogen sulfide (H2S) donor NaSH, and a slow-releasing H2S compound S-propargyl-cysteine (SPRC) which is derived from garlic, have been studied for the immune-regulatory effects on macrophages. The NaSH and SPRC showed the potential to protect the heart and kidney from tissue injury induced by LPS. The immunohistochemistry of F4/80+ revealed that the infiltration of macrophages in the heart and kidney tissues of LPS-treated mice was reduced by NaSH and SPRC. In addition, in the LPS-triggered inflammatory cascade of RAW264.7 macrophage cells, NaSH and SPRC exhibited significantly inhibitory effects on the secretion of inflammatory cytokines, production of reactive oxygen species (ROS), and regulation of the macrophage phenotype from M1-like to M2-like. Moreover, autophagy, a crucial process involved in the elimination of impaired proteins and organelles during oxidative stress and immune response, was induced by NaSH and SPRC in the presence of LPS stimulation. Consequently, there was an increase in the number of mitochondria and an improvement in mitochondrial membrane potential. This process was mainly mediated by PINK1/Parkin pathway mediated mitophagy.

DISCUSSION

These results demonstrated that the immunoregulatory effects of H2S donors were through the PINK1/Parkin-mediated mitophagy pathway. Overall, our study provided a new therapeutic direction in LPS-induced cardiorenal injury.

Cardiorenal damages in mice at early phase after intervention induced by angiotensin II, nephrectomy, and salt intake

The interconnection of heart performance and kidney function plays an important role for maintaining homeostasis through a variety of physiological crosstalk between these organs. It has been suggested that acute or chronic dysfunction in one organ causes dysregulation in another one, like patients with cardiorenal syndrome. Despite its growing recognition as global health issues, still little is known on pathophysiological evaluation between the two organs. Previously, we established a preclinical murine model with cardiac hypertrophy and fibrosis, and impaired kidney function with renal enlargement and increased urinary albumin levels induced by co-treatment with vasopressor angiotensin II (A), unilateral nephrectomy (N), and salt loading (S) (defined as ANS treatment) for 4 weeks. However, how both tissues, heart and kidney, are initially affected by ANS treatment during the progression of tissue damages remains to be determined. Here, at one week after ANS treatment, we found that cardiac function in ANS-treated mice (ANS mice) are sustained despite hypertrophy. On the other hand, kidney dysfunction is evident in ANS mice, associated with high blood pressure, enlarged glomeruli, increased levels of urinary albumin and urinary neutrophil gelatinase-associated lipocalin, and reduced creatinine clearance. Our results suggest that cardiorenal tissues become damaged at one week after ANS treatment and that ANS mice are useful as a model causing transition from early to late-stage damages of cardiorenal tissues.

Cardiorenal syndrome and iron supplementation-more benefits than risks: a narrative review

Intravenous iron administration has emerged as a crucial intervention for managing patients with cardiorenal syndrome (CRS) and iron deficiency, with or without the presence of anemia. Multiple studies have demonstrated the benefits of intravenous iron supplementation in improving anemia, symptoms, and functional capacity in patients with HF and iron deficiency. Furthermore, iron supplementation has been associated with a reduction in hospitalizations for HF exacerbation and the improvement of patients' quality of life and clinical outcomes. In addition to its effects on HF management, emerging evidence suggests a potential positive impact on kidney function in patients with CRS. Studies have shown an increase in estimated glomerular filtration rate and improvements in renal function markers in patients receiving intravenous iron therapy, highlighting the potential of this intervention in patients with CRS. This paper reviews the existing literature on the impact of intravenous iron therapy in these patient populations and explores its effects on various clinical outcomes. Future research endeavors are eagerly awaited to further improve our understanding of its clinical implications and optimize patient outcomes.

Eplerenone improves hyperglycemia and sympathetic excitation in chronic renocardiac syndrome in rats

We aimed to assess the efficacy of eplerenone, a steroidal mineralocorticoid receptor antagonist known to reduce blood pressure and mitigate cardiovascular disease (CVD) progression, in retarding the progression of chronic kidney disease (CKD) and CVD in a rat model of type 4 cardiorenal syndrome (CRS). We grouped rats into four experimental categories: sham surgery, sham treatment with eplerenone, nephrectomy without eplerenone (Nx), and nephrectomy with eplerenone (Nx + EP). For the Nx + EP group, rats received five-sixths nephrectomy, inducing CKD and CVD conditions such as renal hypertension and hyperglycemia, and were then treated with eplerenone (100 mg/kg/day, orally) over 4 weeks after an initial 4-week observation period. Heart rate, blood pressure, blood sugar levels, and sympathetic nerve excitation were monitored biweekly. In addition, assessments of renal and cardiac tissues, including evaluation of renal tubulointerstitial injury, glomerular injury, and cardiomyocyte hypertrophy, were conducted at week 8. Eplerenone administration mitigated CKD and CVD progression in the Nx + EP group, evident by improved blood pressure (217.3 ± 5.4 versus 175.3 ± 5.6), blood sugar (121.8 ± 1.3 versus 145.6 ± 6.0) level, reduced sympathetic nerve excitation, and cardiomyocyte hypertrophy compared to the Nx group. However, renal tubulointerstitial injury, glomerular injury, and cardiovascular dysfunction, which were increased in rats with type 4 CRS, did not show significant changes with eplerenone treatment. Our study demonstrated that eplerenone treatment did not exacerbate type 4 CRS but improved blood pressure, blood sugar levels, sympathetic nerve excitation, and cardiomyocyte hypertrophy in this model.

Gualou xiebai decoction ameliorates cardiorenal syndrome type II by regulation of PI3K/AKT/NF-κB signalling pathway

BACKGROUND

Cardiorenal syndromes type II (CRS2) is a multi-organ ailment that manifests as a combination of cardiac and renal dysfunction, resulting in chronic kidney disease due to chronic cardiac insufficiency. It affects at least 26 million people worldwide, and its prevalence is increasing. Gualou Xiebai Decoction (GXD), a traditional Chinese medicine (TCM) with a rich history of application in the management of coronary artery disease, has been explored for its potential therapeutic benefits in CRS2. Nevertheless, the mechanism by which GXD alleviates CRS2 remains obscure, necessitating further investigation.

PURPOSE

The aim of this study was to assess the effects of the ethanolic extract of GXD on CRS2 and to elucidate the underlying mechanism in a rat model of myocardial infarction, offering a potential target for clinical treatment for CRS2.

STUDY DESIGN AND METHODS

A rat model of CRS2 was induced by surgical myocardial infarction and treated with GXD for 10 weeks. Cardiac function was assessed using echocardiography, while serum and urine biochemistry were analyzed to evaluate potential cardiac and renal damage. Furthermore, tissue samples were obtained for histological, protein, and genetic investigations. In addition, network pharmacology analysis and molecular docking were utilized to predict the primary active compounds, potential therapeutic targets, and interventional pathways through which GXD could potentially exert its effects on CRS2. Subsequently, these predictions were confirmed in vivo and vitro through various analyses.

RESULTS

The current investigation employed echocardiography to exhibit the apparent cardiac remodeling following the induction of myocardial infarction. Damage to the heart and kidneys of CRS2 rats was effectively ameliorated by administration of GXD. The outcomes derived from the analyses of HE and Masson staining indicated that the pathological damage to the heart and kidney tissues of rats in the GXD groups was considerably alleviated. Using network pharmacology analysis, AKT1, IL-6, and TNF-α were identified as plausible therapeutic targets for the treatment of CRS with GXD. Subsequent functional and pathway enrichment analysis of the underlying targets disclosed that the PI3K/AKT/NF-κB signaling pathway may be involved in the mechanism of GXD in the treatment of CRS2. Immunohistochemical, western blot, RT-PCR and immunofluorescence staining were employed to demonstrate that GXD can regulate the PI3K/AKT/NF-κB signaling pathway in the CRS2 rat model. Ultimately, administration of the PI3K/AKT agonist 740Y-P counteracted the effect of diosmetin, which was one of the potential active components of GXD analysed by compound-target-disease network, on p-PI3K and p-AKT in vitro.

CONCLUSIONS

The findings of this study suggest that GXD improves cardiac and renal function in CRS2 rats and that the underlying mechanism involves inhibition of the PI3K/AKT/NF-κB pathway.

Dimethyl Fumarate Ameliorated Cardiorenal Anemia Syndrome and Improved Overall Survival in Dahl/Salt-Sensitive Rats

Cardiovascular disease, chronic kidney disease, and anemia are known to adversely affect each other. Inflammation is commonly involved in these diseases. Cardiorenal anemia syndrome (CRAS) is the name given to this mutually harmful condition. Dimethyl fumarate (DMF) is a Food and Drug Administration-approved antioxidant and anti-inflammatory agent. The purpose of this study was to investigate the effects of DMF on Dahl/salt-sensitive (DS) rats as a CRAS model. Six-week-old DS rats were divided into three groups: the control group, the high-salt (HS) group, and the HS+DMF group. The HS and HS+DMF groups were fed a high-salt diet (8% NaCl) from 6 weeks of age. In the HS+DMF group, DMF (90 mg/kg per day) was orally administered from 6 to 15 weeks of age. Systolic blood pressure was measured every 2 weeks. The heart and renal injuries were assessed with histopathological analysis. The heart and renal expression of mRNAs was assessed by reverse-transcription polymerase chain reaction. DMF significantly improved overall survival, which was shortened by HS in DS rats. Systolic blood pressure increased in the HS group compared with the control group, and DMF tended to suppress this change. DMF ameliorated the cardiac and renal abnormalities confirmed in the HS group by histopathological analysis. Furthermore, the changes in mRNA expressions associated with disease exacerbation in the HS group were suppressed by DMF. DMF also improved anemia. This study suggests that DMF improves overall survival in DS rats through organ-protective effects and is effective against cardiorenal anemia syndrome. SIGNIFICANCE STATEMENT: Dimethyl fumarate was found to improve overall survival in Dahl/salt-sensitive rats, associated with its ability to ameliorate anemia and induce cardioprotective and renoprotective effects through anti-inflammatory and antifibrotic effects.

Updates in Cardiorenal Syndrome

Cardiorenal syndrome is a term that refers to a collection of disorders involving both the heart and kidneys, encompassing multi-directional pathways between the 2 organs mediated through low arterial perfusion, venous congestion, and neurohormonal activation. The pathophysiology is complex and includes hemodynamic and neurohormonal changes, but inconsistent findings from recent studies suggest this is very heterogenous disorder. Management for ADHF remains focused on decongestion and neurohormonal blockade to overcome the intense sodium and fluid avidity of the 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.

Dapagliflozin protects the kidney in a non-diabetic model of cardiorenal syndrome

Cardiorenal syndrome encompasses a spectrum of disorders involving heart and kidney dysfunction, and sharing common risk factors, such as hypertension and diabetes. Clinical studies have shown that patients with and without diabetes may benefit from using sodium-glucose cotransporter 2 inhibitors to reduce the risk of heart failure and ameliorate renal endpoints. Because the underlying mechanisms remain elusive, we investigated the effects of dapagliflozin on the progression of renal damage, using a model of non-diabetic cardiorenal disease. Dahl salt-sensitive rats were fed a high-salt diet for five weeks and then randomized to dapagliflozin or vehicle for the following six weeks. After treatment with dapagliflozin, renal function resulted ameliorated as shown by decrease of albuminuria and urine albumin-to-creatinine ratio. Functional benefit was accompanied by a decreased accumulation of extracellular matrix and a reduced number of sclerotic glomeruli. Dapagliflozin significantly reduced expression of inflammatory and endothelial activation markers such as NF-κB and e-selectin. Upregulation of pro-oxidant-releasing NADPH oxidases 2 and 4 as well as downregulation of antioxidant enzymes were also counteracted by drug treatment. Our findings also evidenced the modulation of both classic and non-classic renin-angiotensin-aldosterone system (RAAS), and effects of dapagliflozin on gene expression of ion channels/transporters involved in renal homeostasis. Thus, in a non-diabetic model of cardiorenal syndrome, dapagliflozin provides renal protection by modulating inflammatory response, endothelial activation, fibrosis, oxidative stress, local RAAS and ion channels.

Cardioprotective effect of abscisic acid in a rat model of type 3 cardio-renal syndrome: Role of NOX-4, P-53, and HSP-70

Cardiorenal syndrome (CRS) is a complex heart and kidney pathophysiologic disorder that leads to a bidirectional interrelationship between them. Abscisic acid (ABA) is a phytohormone that is present in plants, and is known to regulate fundamental physiological functions. This study aimed to explore the efficacy of ABA in surgically induced-CRS type 3 rats. Rats were randomly and equally divided into four groups. Rats in Group 1 received saline (Sham group), Group 2 included control induced-CRS rats, Group 3 rats (CRS+ABA) included CRS rats treated with ABA and Group 4 (CRS + ABA + Verapamil + propofol) were CRS rats treated with Verapamil, propofol and ABA. The rats were treated with the drugs daily for four weeks. At the end of the study, relative heart weight corrected QT interval (QTc), mean blood pressure (MBP), kidney functions, oxidative stress, NADPH oxidase 4 (NOX4), protein 53 (P53), and heat shock proteins-70 (HSP-70) expression was assessed and recorded. ABA led to a significant shortening of the ventricular action potential duration indicated by QTc. Furthermore, it significantly lowered heart weight, MBP, serum creatinine, NOX-4, and P-53 expression and augmented HSP-70 expression. In contrast, adding calcium channel blockers (CCBs) to ABA mitigated this effect. The results suggested that ABA has a potential protective role in CRS-induced cardiac hypertrophy and arrhythmia that could be mediated through inhibition of P-53, NOX-4, and an increase in HSP-70 expression.

Development and Current Role of Sodium Glucose Cotransporter Inhibition in Cardiorenal Metabolic Syndrome

ABSTRACT

Sodium-glucose cotransporter-2 inhibitors were approved as adjunct therapy for the management of type 2 diabetes and have become a high-level recommendation for this population with cardiorenal metabolic syndrome. In addition, evidence continues to grow supporting this class of medications for people with heart failure and chronic kidney disease, regardless of diabetes status. This narrative review summarizes the sodium-glucose cotransporter inhibitors for cardiorenal metabolic syndrome.

Comparative cardioprotective effects of carvedilol versus atenolol in a rat model of cardiorenal syndrome type 4

The incidence of chronic kidney disease is escalating; cardiorenal syndrome (CRS) type 4 is gaining a major health concern causing significant morbidity and mortality, putting major burdens on the healthcare system. This study was designed to compare the cardioprotective effects of carvedilol versus atenolol against CRS type 4 induced by subtotal 5/6 nephrectomy in rats and to explore the underlying mechanisms. Immediately after surgery, carvedilol (20 mg/kg/day) or atenolol (20 mg/kg/day) was added to drinking water for 10 weeks. Carvedilol was more effective than atenolol in improving kidney functions, decreasing elevated blood pressures, attenuating cardiac hypertrophy, reducing serum brain natriuretic peptide, and diminished cardiac fibrous tissue deposition. However, carvedilol was equivalent to atenolol in modulating β1-adrenergic receptors (β1ARs) and cardiac diacylglycerol (DAG) signaling, but carvedilol was superior in modulating β-arrestin2, phosphatidyl inositol 4,5 bisphosphates (PIP2), and caspase 3 levels. Carvedilol has superior cardioprotective effects than atenolol in a rat model of CRS type 4. These protective effects are mediated through modulating cardiac β1ARs/β-arrestin2/PIP2/DAG as well as abating cardiac apoptotic signaling pathways (caspase3/pS473 protein kinase B (Akt)).

Nicorandil Decreases Renal Injury in Patients With Coronary Heart Disease Complicated With Type I Cardiorenal Syndrome

ABSTRACT

Cardiorenal syndrome (CRS) is a group of disorders in which heart or kidney dysfunction worsens each other. This study aimed to explore the improvement effect of nicorandil on cardiorenal injury in patients with type I CRS. Patients with coronary heart disease complicated with type I CRS were enrolled. Based on the conventional treatment, the patients were prospectively randomized into a conventional treatment group and a nicorandil group, which was treated with 24 mg/d nicorandil intravenously for 1 week. Fasting peripheral venous blood serum and urine were collected before and at the end of treatment. An automatic biochemical analyzer and enzyme linked immunosorbent assay were used to detect B-type brain natriuretic peptide (BNP), serum creatinine (Scr) and cystatin C (Cys-C), renal injury index-kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), and interleukin-18 (IL-18) levels. The left ventricular ejection fraction was measured by echocardiography. All measurements were not significantly different between the nicorandil and conventional treatment groups before treatment (all P > 0.05), and BNP, Scr, Cys-C, NGAL, KIM-1, and IL-18 were decreased in the 2 groups at the end of treatment (all P < 0.05). Compared with the conventional treatment group, BNP, Scr, Cys-C, NGAL, KIM-1, and IL-18 were more significantly decreased in the nicorandil group (all P < 0.05) and left ventricular ejection fraction was more significantly increased (P < 0.05). Therefore, nicorandil could significantly improve the cardiac and renal function of patients with type I CRS. This may prove to be a new therapeutic tool for improving the prognosis and rehabilitation of type I CRS.

Establishment of a Drug Screening Model for Cardiac Complications of Acute Renal Failure

Acute renal failure (ARF) is a clinical critical syndrome with rapid and severe decline of renal function. Complications of ARF, especially its cardiac complications (cardiorenal syndrome type 3, CRS-3), are the main causes of death in patients with ARF. However, the shortage and limited efficacy of therapeutic drugs make it significant to establish new large-scale drug screening models. Based on the Nitroreductase/Metronidazole (NTR/MTZ) cell ablation system, we constructed a Tg(cdh17:Dendra2-NTR) transgenic zebrafish line, which can specifically ablate renal tubular epithelial cells. The absence of renal tubular epithelial cells can lead to ARF in zebrafish larvae. The ARF symptoms, such as heart enlargement, slow heart rate and blood stasis, are similar to the clinical manifestations of human CRS-3. Furthermore, two therapeutic drugs (digoxin and enalapril) commonly used in the clinical treatment of heart failure were also effective in alleviating the symptoms of CRS-3 in zebrafish, which proved the effectiveness of this model. Drug screening further discovered a potential drug candidate, α-lipoic acid, which can effectively alleviate the symptoms of CRS-3 through its antioxidant function. Accordingly, we established a new ARF model of zebrafish, which laid a foundation for large-scale screening of new therapeutic drugs for its complications.

Reversing endothelial dysfunction with empagliflozin to improve cardiomyocyte function in cardiorenal syndrome

Sodium-glucose cotransporter 2 inhibitors offer cardiovascular and renal benefits in patients with chronic kidney disease through not yet clearly defined mechanisms. Juni et al. showed that sodium-glucose cotransporter 2 inhibitor empagliflozin exposure in vitro can restore cardiomyocyte function by counteracting harmful effects of uremic serum on the endothelium-cardiomyocyte crosstalk between endothelial cells and cardiomyocytes. The author's findings improved our understanding of cardiovascular impairment in chronic kidney disease and provided new perspectives for the beneficial effects of sodium-glucose cotransporter 2 inhibitor therapy.

Sacubitril-Valsartan Improves Anemia of Cardiorenal Syndrome (CRS)

BACKGROUND AND AIMS

Anemia is a common complication of heart failure and Chronic Kidney Disease (CKD). Sacubitril-valsartan is a novel therapy for the treatment of chronic Heart Failure with a reduced Ejection Fraction (HFrEF). We have evaluated the short-term effects of sacubitril- valsartan on the anemia of CRS.

METHODS

The study group comprised 39 patients with HFrEF, who were followed-up for three months. The study is a retrospective analysis of clinical data. Data of 3 months' and baseline visits were recorded including plasmatic creatinine, glomerular filtration rate, cystatin C, kaliemia, haemoglobin, pro-BNP, and albuminuria.

RESULTS

In all, 34 patients ended the follow-up. Mean sacubitril-valsartan dosage at baseline was 101 ± 62 mg/day and 126 ± 59 mg/day at end. Mean hemoglobin increased from 12.2 ± 1.1 g/dl at baseline to 12.9 ± 1.0 g/dl (p = 0.001,). Prevalence of anemia was 64.7% (95%CI, 47.9-78.5%) at baseline and 38.4 (95%CI, 23.9-55.0%) after the follow-up (p = 0.016). Serum cystatin C levels decreased from 2.71 ± 1.0 to 2.48 ± 1.0 mg/l (p = 0.028). Serum K levels remained unchanged (baseline 4.94 ± 0.60, three months visit 4.94 ± 0.61 mmol/l, p = 0.998).

CONCLUSION

Sacubitril-valsartan improves anemia in CRS patients. An improvement in serum cystatin levels was observed. Few untoward effects were detected. These findings should be confirmed in wider clinical trials.

Effects of Angiotensin-Neprilysin Inhibition in Canines with Experimentally Induced Cardiorenal Syndrome

BACKGROUND

Sacubitril/valsartan (Sac/Val), a combined angiotensin-II receptor blocker (Val) and neprilysin inhibitor (Sac) in a 1:1 molar ratio, was shown to decrease the risk of cardiovascular death or heart failure (HF) hospitalization in patients with HF and reduced left ventricular (LV) ejection fraction. This study examined the effects of Sac/Val on LV structure, function, and bioenergetics, and on biomarkers of kidney injury and kidney function in dogs with experimental cardiorenal syndrome.

METHODS AND RESULTS

Fourteen dogs with cardiorenal syndrome (coronary microembolization-induced HF and renal dysfunction) were randomized to 3 months Sac/Val therapy (100 mg once daily, n = 7) or no therapy (control, n = 7). LV ejection fraction and troponin-I, as well as biomarkers of kidney injury/function including serum creatinine and urinary kidney injury molecule-1 were measured before and at end of therapy and the change (treatment effect change) calculated. Mitochondrial function measures, including the maximum rate of adenosine triphosphate synthesis, were measured in isolated cardiomyocytes at end of therapy. In Sac/Val dogs, the change in ejection fraction increased compared with controls, 6.9 ± 1.4 vs 0.7 ± 0.6%, P < .002, whereas change in troponin I decreased, -0.16 ± 0.03 vs -0.03 ± 0.02 ng/mL, P < .001. Urinary change in kidney injury molecule 1 decreased in Sac/Val-treated dogs compared with controls, -17.2 ± 7.9 vs 7.7 ± 3.0 mg/mL, P < .007, whereas the change in serum creatinine was not significantly different. Treatment with Sac/Val increased adenosine triphosphate synthesis compared with controls, 3240 ± 121 vs 986 ± 84 RLU/µg protein, P < .05.

CONCLUSIONS

In dogs with cardiorenal syndrome, Sac/Val improves LV systolic function, improves mitochondrial function and decreases biomarkers of heart and kidney injury. The results offer mechanistic insights into the benefits of Sac/Val in HF with compromised renal function.

Antihypertensive Effects of Gynura divaricata (L.) DC in Rats with Renovascular Hypertension

Gynura divaricata (L.) DC (Compositae) (GD) could be found in various parts of Asia. It has been used as a traditional medicine to treat diabetes, high blood pressure, and other diseases, but its effects have not yet been scientifically confirmed. Therefore, we aimed at determining whether GD could affect renal function regulation, blood pressure, and the renin-angiotensin-aldosterone system (RAAS). Cardio-renal syndrome (CRS) is a disease caused by the interaction between the kidney and the cardiovascular system, where the acute or chronic dysfunction in one organ might induce acute or chronic dysfunction of the other. This study investigated whether GD could improve cardio-renal mutual in CRS type 4 model animals, two-kidney one-clip (2K1C) renal hypertensive rats. The experiments were performed on the following six experimental groups: control rats (CONT); 2K1C rats (negative control); OMT (Olmetec, 10 mg/kg/day)-treated 2K1C rats (positive control); and 2K1C rats treated with GD extracts in three different doses (50, 100, and 200 mg/kg/day) for three weeks by oral intake. Each group consisted of 10 rats. We measured the systolic blood pressure weekly using the tail-cuff method. Urine was also individually collected from the metabolic cage to investigate the effect of GD on the kidney function, monitoring urine volume, electrolyte, osmotic pressure, and creatinine levels from the collected urine. We observed that kidney weight and urine volume, which would both display typically increased values in non-treated 2K1C animals, significantly decreased following the GD treatment (###p < 0.001 vs. 2K1C). Osmolality and electrolytes were measured in the urine to determine how renal excretory function, which is reduced in 2K1C rats, could be affected. We found that the GD treatment improved renal excretory function. Moreover, using periodic acid-Schiff staining, we confirmed that the GD treatment significantly reduced fibrosis, which is typically increased in 2K1C rats. Thus, we confirmed that the GD treatment improved kidney function in 2K1C rats. Meanwhile, we conducted blood pressure and vascular relaxation studies to determine if the GD treatment could improve cardiovascular function in 2K1C rats. The heart weight percentages of the left atrium and ventricle were significantly lower in GD-treated 2K1C rats than in non-treated 2K1C rats. These results showed that GD treatment reduced cardiac hypertrophy in 2K1C rats. Furthermore, the acetylcholine-, sodium nitroprusside-, and atrial natriuretic peptide-mediated reduction of vasodilation in 2K1C rat aortic rings was also ameliorated by GD treatment (GD 200 mg/kg/day; p < 0.01, p < 0.05, and p < 0.05 vs. 2K1C for vasodilation percentage in case of each compound). The mRNA expression in the 2K1C rat heart tissue showed that the GD treatment reduced brain-type natriuretic peptide and troponin T levels (p < 0.001 and p < 0.001 vs. 2K1C). In conclusion, this study showed that GD improved the cardiovascular and renal dysfunction observed in an innovative hypertension model, highlighting the potential of GD as a therapeutic agent for hypertension. These findings indicate that GD shows beneficial effects against high blood pressure by modulating the RAAS in the cardio-renal syndrome. Thus, it should be considered an effective traditional medicine in hypertension treatment.

Clinical Potential of Targeting Fibroblast Growth Factor-23 and αKlotho in the Treatment of Uremic Cardiomyopathy

Chronic kidney disease is highly prevalent, affecting 10% to 15% of the adult population worldwide and is associated with increased cardiovascular morbidity and mortality. As chronic kidney disease worsens, a unique cardiovascular phenotype develops characterized by heart muscle disease, increased arterial stiffness, atherosclerosis, and hypertension. Cardiovascular risk is multifaceted, but most cardiovascular deaths in patients with advanced chronic kidney disease are caused by heart failure and sudden cardiac death. While the exact drivers of these deaths are unknown, they are believed to be caused by uremic cardiomyopathy: a specific pattern of myocardial hypertrophy, fibrosis, with both diastolic and systolic dysfunction. Although the pathogenesis of uremic cardiomyopathy is likely to be multifactorial, accumulating evidence suggests increased production of fibroblast growth factor-23 and αKlotho deficiency as potential major drivers of cardiac remodeling in patients with uremic cardiomyopathy. In this article we review the increasing understanding of the physiology and clinical aspects of uremic cardiomyopathy and the rapidly increasing knowledge of the biology of both fibroblast growth factor-23 and αKlotho. Finally, we discuss how dissection of these pathological processes is aiding the development of therapeutic options, including small molecules and antibodies, directly aimed at improving the cardiovascular outcomes of patients with chronic kidney disease and end-stage renal disease.

Inhibition of apoptosis signal-regulating kinase 1 ameliorates left ventricular dysfunction by reducing hypertrophy and fibrosis in a rat model of cardiorenal syndrome

BACKGROUND

Cardiorenal syndrome (CRS) is a major health burden worldwide in need of novel therapies, as current treatments remain suboptimal. The present study assessed the therapeutic potential of apoptosis signal-regulating kinase 1 (ASK1) inhibition in a rat model of CRS.

METHODS

Adult male Sprague-Dawley rats underwent surgery for myocardial infarction (MI) (week 0) followed by 5/6 subtotal nephrectomy (STNx) at week 4 to induce to induce a combined model of heart and kidney dysfunction. At week 6, MI + STNx animals were randomized to receive either 0.5% carboxymethyl cellulose (Vehicle, n = 15, Sham = 10) or G226 (15 mg/kg daily, n = 11). Cardiac and renal function was assessed by echocardiography and glomerular filtration rate (GFR) respectively, prior to treatment at week 6 and endpoint (week 14). Haemodynamic measurements were determined at endpoint prior to tissue analysis.

RESULTS

G226 treatment attenuated the absolute change in left ventricular (LV) fractional shortening and posterior wall thickness compared to Vehicle. G226 also attenuated the reduction in preload recruitable stroke work. Increased myocyte cross sectional area, cardiac interstitial fibrosis, immunoreactivity of cardiac collagen-I and III and cardiac TIMP-2 activation, were significantly reduced following G226 treatment. Although we did not observe improvement in GFR, G226 significantly reduced renal interstitial fibrosis, diminished renal collagen-I and -IV, kidney injury molecule-1 immunoreactivity as well as macrophage infiltration and SMAD2 phosphorylation.

CONCLUSION

Inhibition of ASK1 ameliorated LV dysfunction and diminished cardiac hypertrophy and cardiorenal fibrosis in a rat model of CRS. This suggests that ASK1 is a critical pathway with therapeutic potential in the CRS setting.

Melatonin fine-tunes intracellular calcium signals and eliminates myocardial damage through the IP3R/MCU pathways in cardiorenal syndrome type 3

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.

Cardiac Remodeling in Chronic Kidney Disease

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.

The therapeutic impact of entresto on protecting against cardiorenal syndrome-associated renal damage in rats on high protein diet

BACKGROUND

This study tested the hypothesis that Entresto could safely and effectively preserve heart and kidney function in rats with cardiorenal syndrome (CRS) induced by 5/6 nephrectomy and intra-peritoneal doxorubicin administration (accumulated dosage up to 7.5 mg/kg) together with daily high-protein-diet (H^PD).

METHODS AND RESULTS

Adult male Sprague-Dawley rats (n = 24) were equally categorized into Group 1 (sham-operated control + H^PD), Group 2 (CRS + H^PD) and Group 3 [CRS + H^PD + Entresto (100 mg/kg/day orally) since Day 14 after CRS induction] and euthanized by Day 63 after CRS induction. By Day 63, circulatory BUN and creatinine levels and ratios of urine protein to creatinine were significantly higher in Group 2 than those in Groups 1 and 3, and significantly higher in Group 3 than in Group 1, whereas left-ventricular ejection fraction and kidney weight showed an opposite pattern among all groups (all p < 0.001). Microscopically, fibrosis area and intensity of oxidative stress (i.e., DCFDA stain) in kidney/heart tissues exhibited a pattern identical to that of creatinine level among all groups (all p < 0.0001). Kidney injury score and protein expressions of autophagy (i.e., beclin-1/Atg-5/protein ratio of LC3-BII/LC3-BI), fibrosis (Smad3/TGF-ß), apoptosis (mitochondrial-Bax/capase2/3/9), oxidative-stress (NOX-4/oxidized protein/xanthine-oxidase/catalase), membranous p47phox phosphorylation and mitochondrial-damage biomarker (cytosolic-cytochrome-C) were higher in Group 2 than those in Groups 1 and 3, and significantly higher in Group 3 than in Group 1, while protein expressions of anti-apoptosis (Bcl-2/Bcl-XL) and mitochondrial integrity (mitochondrial-cytochrome-C) markers displayed an opposite pattern among all groups in kidney tissues (all p < 0.0001).

CONCLUSION

Oral administration of entresto was safe and could offer protection against CRS-induced heart and kidney damage.

Spironolactone inhibits endothelial-mesenchymal transition via the adenosine A2A receptor to reduce cardiorenal fibrosis in rats

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.

Autophagy as an emerging target in cardiorenal metabolic disease: From pathophysiology to management

Although advances in medical technology and health care have improved the early diagnosis and management for cardiorenal metabolic disorders, the prevalence of obesity, insulin resistance, diabetes, hypertension, dyslipidemia, and kidney disease remains high. Findings from numerous population-based studies, clinical trials, and experimental evidence have consolidated a number of theories for the pathogenesis of cardiorenal metabolic anomalies including resistance to the metabolic action of insulin, abnormal glucose and lipid metabolism, oxidative and nitrosative stress, endoplasmic reticulum (ER) stress, apoptosis, mitochondrial damage, and inflammation. Accumulating evidence has recently suggested a pivotal role for proteotoxicity, the unfavorable effects of poor protein quality control, in the pathophysiology of metabolic dysregulation and related cardiovascular complications. The ubiquitin-proteasome system (UPS) and autophagy-lysosomal pathways, two major although distinct cellular clearance machineries, govern protein quality control by degradation and clearance of long-lived or damaged proteins and organelles. Ample evidence has depicted an important role for protein quality control, particularly autophagy, in the maintenance of metabolic homeostasis. To this end, autophagy offers promising targets for novel strategies to prevent and treat cardiorenal metabolic diseases. Targeting autophagy using pharmacological or natural agents exhibits exciting new strategies for the growing problem of cardiorenal metabolic disorders.

Differential Effects of Levosimendan and Dobutamine on Glomerular Filtration Rate in Patients With Heart Failure and Renal Impairment:A Randomized Double-Blind Controlled Trial

Background The management of the cardiorenal syndrome in advanced heart failure is challenging, and the role of inotropic drugs has not been fully defined. Our aim was to compare the renal effects of levosimendan versus dobutamine in patients with heart failure and renal impairment. Methods and Results In a randomized double-blind study, we assigned patients with chronic heart failure (left ventricular ejection fraction <40%) and impaired renal function (glomerular filtration rate <80 mL/min per 1.73 m2) to receive either levosimendan (loading dose 12 μg/kg+0.1 μg/kg per minute) or dobutamine (7.5  μg/kg per minute) for 75 minutes. A pulmonary artery catheter was used for measurements of systemic hemodynamics, and a renal vein catheter was used to measure renal plasma flow by the infusion clearance technique for PAH (para-aminohippurate) corrected by renal extraction of PAH . Filtration fraction was measured by renal extraction of chromium ethylenediamine tetraacetic acid. A total of 32 patients completed the study. Following treatment, the levosimendan and dobutamine groups displayed similar increases in renal blood flow (22% and 26%, respectively) with no significant differences between groups. Glomerular filtration rate increased by 22% in the levosimendan group but remained unchanged in the dobutamine group ( P=0.012). Filtration fraction was not affected by levosimendan but decreased by 17% with dobutamine ( P=0.045). Conclusions In patients with chronic heart failure and renal impairment, levosimendan increases glomerular filtration rate to a greater extent than dobutamine and thus may be the preferred inotropic agent for treating patients with the cardiorenal syndrome. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT 02133105.

Clinical therapeutic strategy of recombinant human brain natriuretic peptide and dopamine in cardiorenal syndrome type 4 patients combined with hypotension

Aim of the present study is to investigate the clinical efficacy of recombinant human brain natriuretic peptide (rhBNP) and dopamine combination treatment in patients with cardiorenal syndrome type 4 (CRS4) combined with hypotension. A total of 160 CRS4 patients admitted to our hospital from July 2010 to December 2014 were recruited, and were randomly divided into two groups, the observational group (n=80) and the control group (n=80). CRS4 patients treated with dopamine were recruited into the control group. Patients in the observational group were given rhBNP and dopamine combination treatment once every 8 h. Both groups received conventional treatments and the course of treatment was 7 days. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), serum creatinine (SCr), N-terminal brain natriuretic peptide precursor (Nt-proBNP), creatinine clearance (CCr), left ventricular end-diastolic diameter (LVEDd), left ventricular ejection fraction (LVEF), Stroke volume (SV), urine volume and adverse reactions before and after treatment were compared. The observational group showed significant changes in the levels of SBP, DBP and HR compared with the control group (P<0.05). The levels of SCr and Nt-proBNP decreased significantly in the observational group than those in the control group (P<0.05). The levels of CCr, LVEF, SV and urine volume increased significantly in the observational group than those in the control group (P<0.05). Patients in the observational group had mild and tolerable adverse reactions. rhBNP combined with dopamine infusion has good clinical efficacy and mild adverse effects in treatment of CRS4.

Steroidal and Novel Non-steroidal Mineralocorticoid Receptor Antagonists in Heart Failure and Cardiorenal Diseases: Comparison at Bench and Bedside

Characterization of mice with cell-specific deletion or overexpression of the mineralocorticoid receptor (MR) shed a new light on its role in health and disease. Pathophysiological MR activation contributes to a plethora of deleterious molecular mechanisms in the development of cardiorenal diseases like chronic kidney disease (CKD) and heart failure (HF). Accordingly, the available steroidal MR antagonists (MRAs) spironolactone (first generation MRA) and eplerenone (second generation MRA) have been shown to be effective in reducing cardiovascular (CV) mortality and morbidity in patients with chronic HF and a reduced left ventricular ejection fraction (HFrEF). However, they remain underutilized, in large part owing to the risk inducing severe adverse events including hyperkalemia and worsening of kidney function, particularly when given on top of inhibitors of the renin angiotensin system (RAS) to patients with concomitant kidney dysfunction. Novel, potent, and selective non-steroidal MRAs (third generation) were identified in drug discovery campaigns and a few entered clinical development recently. One of these is finerenone with different physicochemical, pharmacokinetics, and pharmacological properties in comparison with the steroidal MRAs. Available data from five clinical phase II trials with finerenone in more than 2,000 patients with HF and additional CKD and/or diabetes as well as in patients with diabetic kidney disease demonstrated that neither hyperkalemia nor reductions in kidney function were limiting factors to its use. Moreover, finerenone demonstrated a nominally improved outcome compared to eplerenone in a phase IIb trial with 1,066 patients with HFrEF and concomitant type 2 diabetes mellitus (T2DM) and/or CKD.

The cardioprotective effect of melatonin and exendin-4 treatment in a rat model of cardiorenal syndrome

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.

Hand-carried ultrasound use in clinical nephrology: Case report

BACKGROUND

Correctly assessing and managing volume status are critical elements of daily care for patients managed by nephrologists. However, intravascular volume is difficult to assess by physical examination alone.

METHODS

We present vignettes illustrating the potential for using hand-carried ultrasound (HCU) to improve volume assessment in common clinical scenarios faced by the renal consultant in the hospital setting. These include patients with acute kidney injury and patients treated with hemodialysis.

RESULTS

We used HCU to provide essential information about volume status which is otherwise not readily available. HCU allowed objective assessment of volume status, helping with clinical management of hospitalized patients and potentially avoiding harm.

CONCLUSION

HCU can complement physical examination for volume assessment in hospitalized patients with acute kidney injury or those on hemodialysis. Our report highlights the need for systematic research in this area.

Valsartan attenuates cardiac and renal hypertrophy in rats with experimental cardiorenal syndrome possibly through down-regulating galectin-3 signaling

OBJECTIVE

Aortocaval fistula (AV) induced chronic volume overload in rats with preexisting mild renal dysfunction (right kidney remove: UNX) could mimic the type 4 cardiorenal syndrome (CRS): chronic renocardiac syndrome. Galectin-3, a β-galactoside binding lectin, is an emerging biomarker in cardiovascular as well as renal diseases. We observed the impact of valsartan on cardiac and renal hypertrophy and galectin-3 changes in this model.

MATERIALS AND METHODS

Adult male Sprague-Dawley (SD) rats (200-250 g) were divided into S (Sham, n = 7), M (UNX+AV, n = 7) and M+V (UNX+AV+valsartan, n = 7) groups. Eight weeks later, cardiac function was measured by echocardiography. Renal outcome was measured by glomerular filtration rate, effective renal plasma flow, renal blood flow and 24 hours albuminuria. Immunohistochemistry and real-time PCR were used to evaluate the expressions of galectin-3 in heart and renal.

RESULTS

Cardiac hypertrophy and renal hypertrophy as well as cardiac enlargement were evidenced in this AV shunt induced chronic volume overload rat model with preexisting mild renal dysfunction. Cardiac and renal hypertrophy were significantly attenuated but cardiac enlargement was unaffected by valsartan independent of its blood pressure lowering effect. 24 hours urine albumin was significantly increased, which was significantly reduced by valsartan in this model. Immunohistochemistry and real-time PCR evidenced significantly up-regulated galectin-3 expression in heart and kidney and borderline increased myocardial collagen I expression, which tended to be lower post valsartan treatment.

CONCLUSIONS

Up-regulated galectin-3 signaling might also be involved in the pathogenesis in this CRS model. The beneficial effects of valsartan in terms of attenuating cardiac and renal hypertrophy and reducing 24 hours albumin in this model might partly be mediated through down-regulating galectin-3 signal pathway.

[Diuretics in heart failure and Karl Popper's turkey]

Heart failure and renal failure often coexist in the same patient. This condition is commonly referred to as cardiorenal syndrome. When this occurs, patient survival worsens significantly with increasing degree of renal dysfunction. Management of this complex patient poses treatment challenges because of unstable hemodynamics (the problem is to reduce congestion without affecting organ perfusion) and very high mid-term in-hospital mortality. Congestion is a typical feature of this syndrome, and use of diuretics is mandatory. Loop diuretics should be administered first. However, poor attention to pharmacodynamic and pharmacokinetic properties of loop diuretics may contribute to the development of diuretic resistance leading to iatrogenic hyponatremia. Accordingly, emphasis is given to the importance of sequential nephron blockade to reduce the number of non-responder patients to diuretics and to recognize a possible role for acquaretics.

Protective effects of valsartan and benazepril combined with atorvastatin on cardiorenal syndrome in rats

OBJECTIVE

To study the protective effects of valsartan (Val) and benazepril, (Ben) combined with atorvastatin (Ato), on cardiorenal syndrome (CRS) in rats.

MATERIALS AND METHODS

After establishing cardiorenal syndrome model, the rats were randomly divided into control, Ato, Ben+Ato and Val+Ato groups, which were treated with corresponding drugs. Before and 4 weeks after treatment, the serum creatinine (Scr), blood urea nitrogen (BUN), type-B natriuretic peptide (BNP), aldosterone (ALD), angiotensin (Ang) II, C-reactive protein (CRP), blood lipid and urine protein were determined. The left ventricular systolic pressure (LVSP), left ventricular diastolic pressure (LVDP), left ventricular end-diastolic pressure (LVEDP) as well as maximum rising and falling rates of left ventricular pressure (±dp/dtmax) were detected. The heart weight index was also determined.

RESULTS

6, 3, 1 and 2 rats control, Ato, Ben+Ato and Val+Ato groups died, respectively. Compared with control group, the serum Cr, BUN, BNP, ALD, CRP and urinary protein levels in treatment groups significantly decreased, and the blood lipid level, LVDP, LVEDP and heart weight index significantly decreased, with increased LVSP. No statistically significant difference was observed among treatment groups.

CONCLUSIONS

Valsartan and benazepril, combined with atorvastatin, can have significant protective effects on cardiorenal functions of rats with CRS, with no significant difference between these two drugs.

Hepatorenal syndrome and type 1 and 2 cardiorenal syndromes: distinct competing medical therapies applied to a similar background of vasomotor reactive nephropathy

The authors summarize some current views regarding the pharmacologic therapies of hepatorenal and cardiorenal syndromes, respectively. A common pathogenetic background of the two edematous disorders is outlined, consisting in reduced effective blood arterial volume ‑ due to the splanchnic vasodilation in the hepatorenal syndrome (HRS) and to the fall in cardiac output and the rise in central venous pressure in cardiorenal syndrome (CRS). In both diseases, arterial underfilling elicits multiple water- and sodium- retentive mechanisms, by activating sympathetic nervous system and stimulating both rennin-angiotensin-aldosterone and vasopressin systems. These neurohormonal adjustments subsequently concur to a vasomotor nephropathy which originates - as a same kind of vasoconstrictor reflex renal response ‑ from the splanchnic vasodilation, in the case of liver cirrhosis, or from the fall in renal perfusion and filtration gradients in the case of cardiorenal syndrome. Despite these pathogenetic similarities, the renal insufficiency of HRS compared to that of CRS is treated using diametrically opposite approaches: actually withdrawal of diuretics and administration of vasoconstrictor agents is the first choice in the case of HRS, while CRS is tackled by forcing diuretic regimen and by continuing vasodilator treatment with ACE-inhibitors. The pros and cons of these strategies ‑ which are still matter of debate among the physicians and researchers ‑ are then succinctly presented and discussed.

Management of cardiorenal metabolic syndrome in diabetes mellitus: a phytotherapeutic perspective

Cardiorenal syndrome (CRS) is a complex disease in which the heart and kidney are simultaneously affected and their deleterious declining functions are reinforced in a feedback cycle, with an accelerated progression. Although the coexistence of kidney and heart failure in the same individual carries an extremely bad prognosis, the exact cause of deterioration and the pathophysiological mechanisms underlying the initiation and maintenance of the interaction are complex, multifactorial in nature, and poorly understood. Current therapy includes diuretics, natriuretic hormones, aquaretics (arginine vasopressin antagonists), vasodilators, and inotropes. However, large numbers of patients still develop intractable disease. Moreover, the development of resistance to many standard therapies, such as diuretics and inotropes, has led to an increasing movement toward utilization and development of novel therapies. Herbal and traditional natural medicines may complement or provide an alternative to prevent or delay the progression of CRS. This review provides an analysis of the possible mechanisms and the therapeutic potential of phytotherapeutic medicines for the amelioration of the progression of CRS.

Effect of vitamin D analogues on acute cardiorenal syndrome: a laboratory rat model

BACKGROUND

Vitamin D has been shown to induce beneficial effects on cardiovascular and renal morbidity by regulating inflammation and tissue fibrosis.

OBJECTIVES

To evaluate the effect of vitamin D analogues on cardiac function and fibrosis in an animal model of cardiorenal syndrome.

METHODS

Unilateral nephrectomy was performed and myocardial infarction induced in rats. The rats were treated with vitamin D receptor activator (VDRA, paricalcitol, 40 ng/250 g x 3/week) versus a vehicle. A third group of animals, which served as the control, underwent sham surgery and received no treatment. After 4 weeks of treatment, cardiac function and fibrosis were assessed by trans-thoracic echo and histology, respectively. As a parameter of systemic inflammation, previously shown to be altered in acute coronary syndrome, T regulatory (Treg) cell levels were measured by flow cytometry. Renal dysfunction was documented by standard laboratory tests.

RESULTS

After 4 weeks of treatment, no significant improvement in cardiac function parameters was noted following VDRA administration. VDRA treatment did not significantly alter Treg cell systemic levels. Consistently, despite a trend toward less extent of myocardial fibrosis, we found no clear beneficial effects of VDRA on myocardial tissue inflammation and remodeling.

CONCLUSIONS

Vitamin D treatment showed no beneficial effects on cardiac function parameters and fibrosis in an animal model of cardiorenal syndrome.

[Cardiorenal syndrome by heart failure]

Cardiorenal (CR) syndrome is defined for the purposes of the following text mainly as primary cardiac dysfunction with a consequent failure of renal haemodynamics. Heart failure leads to a decrease in cardiac output and to the activation of vasoconstrictors; this gradually precipitates a decrease in the level of renal perfusion, the vasoconstriction of renal vessels and a decrease in glomerular filtration with a gradual development of renal failure. The following paper analyses the pathophysiological mechanisms, the characteristics of the patients, the role of medication during CR syndrome, the relationship between proteinuria and anaemia during CR syndrome and the application of bio-markers and pulmonary hypertension in the prognosis of patients with CR syndrome.

Potential effects of digoxin on long-term renal and clinical outcomes in chronic heart failure

BACKGROUND

Digitalis glycosides are known to improve the hemodynamic and neurohormonal perturbations that contribute to heart failure (HF)-induced renal dysfunction (RD). The objective of this study was to determine if randomization to digoxin is associated with improvement in renal function (IRF) and to evaluate if patients with digoxin-induced IRF have improved clinical outcomes.

METHODS AND RESULTS

Patients in the Digitalis Investigation Group (DIG) dataset with protocol-driven 1-year serum creatinine levels (performed in a central laboratory; n = 980) were studied. IRF was defined as a postrandomization ≥20% increase in estimated glomerular filtration rate (eGFR). IRF occurred in 15.5% of the population (mean improvement in eGFR 34.5 ± 15.4%) and was more common in patients randomized to digoxin (adjusted odds ratio 1.6; P = .02). In patients without IRF, digoxin was not associated with reduced death or hospitalization (adjusted hazard ratio [HR] 0.96, 95% CI 0.8-1.2; P = .67). However, in the group with IRF, digoxin was associated with substantially improved hospitalization-free survival (adjusted HR 0.49, 95% CI 0.3-0.8; P = .006; P interaction = .026).

CONCLUSIONS

In this subset of the DIG trial, digoxin was associated with long-term improvement in kidney function and, in patients demonstrating this favorable renal response, reduction in death or hospitalization. Additional research is necessary to confirm these hypothesis-generating findings.

[Influence of erythropoietin therapy on systolic function of myocardium in patients with cardiorenal syndrome on hemodialysis]

We observed 93 patients with CRS 2,4,5 types having anemia, systolic dysfunction of left ventricle (LV) - EF ≤45% and heart failure functional class (FC) II-IV (NYHA). All patients are under HD and were treated with EPO 3 times per week in a period of 6 months. We revealed improvement of LV EF 4,3 % and HF FC after EPO treatment and concluded that EPO therapy causes regression of LV hypertrophy, improves LV function and quality of life.

[Cardiorenal anemia syndrome (review)]

Cardiorenal anemia syndrome (CRAS) refers to the simultaneous presence of anemia, heart failure (HF), and chronic kidney disease (CKD) that forms a pathologic triad with an observe impact on morbidity and mortality. Certain researches were made regarding the usage of erythropoietin (EPO) in patients with the above mentioned disorders. This leads to the improvement of left ventricular function, quality of life and physical tolerance with decreased risk of hospitalization. Despite successful anemia treatment with EPO in dialysis patients with CKD, HF and cardiorenal syndrome type 2, it should be important to reveal the target Hb level and role of EPO in this category of patients. According to European guidelines in 85% of hemodialysis patients targeted Hb level should be no more than 11g/dl, moreover, the treatment of anemia can be organized before dialysis and it will certainly increase the quality of life in this type of patients.

Diuretics in heart failure: practical considerations

This review discusses the role of diuretics in heart failure by focusing on different classifications and mechanisms of action. Pharmacodynamic and pharmacokinetic properties of diuretics are elucidated. The predominant discussion highlights the use of loop diuretics, which are the most commonly used drugs in heart failure. Different methods of using this therapy in different settings along with a comprehensive review of the side-effect profile are highlighted. Special situations necessitating adjustment and the phenomenon of diuretic resistance are explained.

Current therapeutic strategies in cardiorenal syndrome

Cardiorenal syndromes (CRS) are disorders of the heart and kidneys in which an acute or chronic dysfunction in one organ may induce acute or chronic dysfunction of the other. Primary disorders of one of these two organs often result in secondary dysfunction or injury of the other. The lack of specific trials in this field highlights the need for further studies aimed to assess titration and appropriate dosages of drugs, according to both the etiology of chronic heart failure (CHF) and also the severity of underlying renal dysfunction. Moreover, the most recent clinical trials evaluating clinical and renal outcome in acute heart failure syndromes (AHFS), failed to demonstrate an improvement in renal function and perfusion. Therefore, Current American and European Guidelines for AHFS does not provide specific recommendation for patients with renal impairment. In this scenario several questions regarding the drugs, their recommended dosage and potential adverse effects on cardiac and renal outcome need to be addressed. Subsequently, therapy inducing an improvement in the renal function, a reduction of neurohormonal activation and an improvement of renal blood flow, could lead to a reduction in mortality and hospitalization in patients with CRS.

Role of iron deficiency and anemia in cardio-renal syndromes

Chronic heart failure is a common disorder associated with unacceptably high mortality rates. Chronic renal disease and anemia are two important comorbidities that significantly influence morbidity and mortality in patients with chronic heart failure (CHF). Progress in CHF again may cause worsening of kidney function and anemia. To describe this vicious cycle, the term cardio-renal anemia syndrome has been suggested. Iron deficiency is part of the pathophysiology of anemia in both CHF and chronic kidney disease, which makes it an interesting target for treatment of anemia in cardio-renal anemia syndrome. Recently, studies have highlighted the potential clinical benefits of treating iron deficiency in patients with CHF, even if these patients are nonanemic. This article summarizes studies investigating the influence of iron deficiency with or without anemia in chronic kidney disease and CHF and gives an overview of preparations of intravenous iron currently available.

Cardio-renal syndrome: an entity cardiologists and nephrologists should be dealing with collegially

Heart failure may lead to acute kidney injury and vice versa. Chronic kidney disease may affect the clinical outcome in terms of cardiovascular morbidity and mortality while chronic heart failure may cause CKD. All these disorders contribute to the composite definition of cardio-renal syndromes. Renal impairment in HF patients has been increasingly recognized as an independent risk factor for morbidity and mortality; however, the most important clinical trials in HF tend to exclude patients with significant renal dysfunction. The mechanisms whereby renal insufficiency worsens the outcome in HF are not known, and several pathways could contribute to the "vicious heart/kidney circle." Traditionally, renal impairment has been attributed to the renal hypoperfusion due to reduced cardiac output and decreased systemic pressure. The hypovolemia leads to sympathetic activity, increased renin-angiotensin-aldosterone pathways and arginine-vasopressin release. All these mechanisms cause fluid and sodium retention, peripheral vasoconstriction and an increased congestion as well as cardiac workload. Therapy addressed to improve renal dysfunction, reduce neurohormonal activation and ameliorate renal blood flow could lead to a reduction in mortality and hospitalization in patients with cardio-renal syndrome.

[Vitamin D in the treatment of cardiorenal syndrome in patients with chronic nephropathy]

AIM

To determine place of vitamin D in prevention and treatment of cardiorenal syndrome (CRS) and chronic allograft nephropathy (CAN) in the aspect of myocardial and renal reparation.

METHODS AND MATERIAL

In Russia and the Netherlands we included in a randomized placebo controlled study 120 vitamin D deficient [25(OH) vitamin D<40 mol/l] recipients of asystolic and cadaveric donors. Patients were divided in 4 groups: paricalcitol (2-4 g/day) group (n=28), calcitriol (1-6 g/day orally) group (n=28), diet (1200-1800 IU/day of vitamin D with multivitamins and from foodstuffs) group (n=26), placebo with diet control group (n=27).

RESULTS

After 180 days degree of CAN according to the Banff classification was 1.24 and 1.22 in paricalcitol and calcitriol groups, respectively, compared with 1.43 and 1.68 in diet and placebo groups, respectively (p<0.05). Glomerular filtration rate (GFR) changed from 46.7 to 84.4, 81.4, 76.8, and 54.5 ml/min/1.73 m3 in paricalcitol, calcitriol, diet and placebo groups, respectively. Fluorescence activated cell scanning (FACS) analysis allowed to detect quantitative induction of SP+ cells amounting 7.4, 2.9 and 1.2%; 7.2, 2.7; and 1.1%; 6.1, 2.9 and 1.2%; 9.3, 1.3 and 0.7% of peripheral blood progenitors, renal epithelial cells, and cardiomyocytes in paricalcitol, calcitriol, diet and placebo groups, respectively. Levels of CD133, CD34, CD73, and CD105 were significantly elevated in patients of paricalcitol (median 161, range 0-834 copies), calcitriol (163, 0-721), and diet (119, 0-401) groups, compared with the placebo group (0,0-41), p<0.01. Level of nuclear vitamin D receptor (VDR) protein in renal tissue homogenizate and myocardium achieved 584, 599, 478, and 333 mole VRD/mg and 801, 715, 654, and 389 Φmole VRD/mg of protein in paricalcitol, calcitriol, diet and placebo groups, respectively (p<0.01). Circulating progenitor stem cells demonstrated comparatively high level of VDR expression--529, 526, 401, and 211 mole VRD/mg in CD133, CD34 cells; 432, 414, 303, and 290 mole VRD/mg in CD73, CD105 cells; 549, 558, 442, and 302 φmole VRD/mg in SP+ cells in paricalcitol, calcitriol, diet and placebo groups, respectively (p<0.05). Hypercalcemia was detected in 4(14%) patients in calcitriol group (p<0.001). Under influence of antihypertensive therapy arterial pressure decreased after transplantation from 180/101 to 143/87, 141/94, 147,102, and 165/101 mm Hg in paricalcitol, calcitriol, diet and placebo groups, respectively (p<0.01). NYHA heart failure functional class changed from 2.3 to 1.8, 1.9, 1.9, and 2.5 in paricalcitol, calcitriol, diet and placebo groups, respectively (p<0.01). In 6 months after transplantation average CCS scores were 533 (0-998), 611 (0-1712), 524 (122-1278) and 990 (120-1800) cells in paricalcitol, calcitriol, diet and placebo groups, respectively (p<0.05).

CONCLUSIONS

Vitamin D is an effective mean of prevention and treatment of CRS and CAN, stimulator of reparation of renal and myocardial tissues. Optimal for wide clinical practice is the use of active vitamin D analog paricalcitol (2-4 g/day) as well as special diet with multivitamins (up to 1800 IU of cholecalciferol).

[Cardiorenal syndrome]

Cardiac and renal disease are common and frequently coexist, resulting in increased risk of mortality, morbidity and cost of care. The interaction between heart and kidney is refered to as cardiorenal syndrome, but a consensus definition has not been established. Also, there are limited data about the true incidence, the pathophisiology is poorly understood and standardized diagnostic criteria are lacking. Because the process is complex, treatment can be a challenge despite the novel therapies. This paper addresses all the complex interactive aspects of the cardiorenal relationship, from pathophysiology to epidemiology, diagnosis and treatment, to have more clear perspectives on the future therapeutic approaches to this deadly association.