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.

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.

[Connotation of Shenqi Pills based on severe cases in cardiovascular care unit and modern pathophysiological mechanism and application of Shenqi Pills for heart failure, renal failure, cardiorenal syndrome, and diuretic resistance in critical care medicine].

Shenqi Pills, first recorded in Essentials from the Golden Cabinet(Jin Kui Yao Lue) from ZHANG Zhong-jing in Han dynasty, have the effect of warming and tonifying the kidney Qi and are mainly used for the treatment of insufficiency of kidney Qi and kidney Yang. According to modern medicine, kidney Qi involves heart function, kidney function, immune function, and so on. The clinical indications of Shenqi Pills include kidney deficiency, abnormal fluid, and abnormal urination, and the last one is classified into little urine, much urine, and dysuria. In clinical settings, Shenqi Pills can be applied for the treatment of heart failure, renal failure, cardiorenal syndrome, and diuretic resistance, as well as endocrine, urological, orthopedic, and other chronic degenerative diseases. Shenqi Pills are ideal prescriptions for the weak constitution and emergency treatment. It is of great value and significance to carry out in-depth research on the connotation of the classic articles by integrating TCM and western medicine based on "pathogenesis combined with pathology and drug properties combined with pharmacology".

[Zhenwu Decoction:connotation interpretation based on severe cases and modern pathophysiological mechanisms and application in treatment of heart failure in critical care unit].

Zhenwu Decoction is recorded in Treatise on Febrile Diseases by an outstanding physician ZHANG Zhong-jing in the Han dynasty. With effect of warming yang, transforming Qi, and promoting urination, Zhenwu Decoction is mainly used to treat edema due to yang deficiency. The studies of the severe and critical cases and the pathophysiological mechanisms have demonstrated that the record of Zhenwu Decoction in Treatise on Febrile Diseases describes the clinical symptoms and therapeutic regimen of acute heart failure. The syndrome treated by this formula may be related to the misdiagnosis and wrong treatment. Due to the difficult distinguishing between cardiogenic dyspnea and pulmonary dyspnea, high doses of Ephedrae Herba may be misused for inducing sweating, which may finally lead to the acute aggravation of heart failure, electrolyte disorder, and pulmonary infection. The syndrome treated by Zhenwu Decoction can illustrate the lack of experience of ancient physicians in treating acute heart failure. The description of "trembling and shivering" may be the clinical manifestation of heart failure, which is an upgraded version of "trembling and shaking" treated by Linggui Zhugan Decoction.(1)In terms of diseases, Zhenwu Decoction is suitable for the treatment of acute or chronic heart failure, cardiorenal syndrome, and diuretic resistance. The decoction is especially suitable for treating whole heart failure, acute heart failure, heart failure with reduced ejection fraction, and heart failure with the syndrome of sold and dampness. In addition, it can be used to treat both type Ⅱ and type Ⅳ cardiorenal syndrome.(2)In terms of symptoms, Zhenwu Decoction can be used for treating chest tightness, palpitations, lower limb edema, difficult urination or increased urine output, fear of cold, pale fat tongue with teeth marks, white and slippery tongue fur, and deep or slow pulse.(3)In terms of the pharmacological mechanism, Zhenwu Decoction treats heart failure following the principle of promoting urination, expanding blood vessels, and invigorating heart in modern medicine. Aconiti Lateralis Radix Praparata is the sovereign herb in the formula, with the recommended dosage of 30-60 g. However, arrhythmia may be caused by high doses of Aconiti Lateralis Radix Praparata, which should be used with concern. In addition to Zhenwu Decoction, Shenqi Pills, Renshen Decoction, Wuling Powder, and Fangji Huangqi Decoction with the effect of invigorating spleen, replenishing Qi, warming Yang, and promoting urination can be used in the recovery stage. The therapy of reinforcing Yang was the last choice for critical cases due to the lack of medical conditions, unclear clinical diagnosis in history, which should be treated objectively now.

Zhenwu Decoction:connotation interpretation based on severe cases and modern pathophysiological mechanisms and application in treatment of heart failure in critical care unit / 中国中药杂志

Zhenwu Decoction is recorded in Treatise on Febrile Diseases by an outstanding physician ZHANG Zhong-jing in the Han dynasty. With effect of warming yang, transforming Qi, and promoting urination, Zhenwu Decoction is mainly used to treat edema due to yang deficiency. The studies of the severe and critical cases and the pathophysiological mechanisms have demonstrated that the record of Zhenwu Decoction in Treatise on Febrile Diseases describes the clinical symptoms and therapeutic regimen of acute heart failure. The syndrome treated by this formula may be related to the misdiagnosis and wrong treatment. Due to the difficult distinguishing between cardiogenic dyspnea and pulmonary dyspnea, high doses of Ephedrae Herba may be misused for inducing sweating, which may finally lead to the acute aggravation of heart failure, electrolyte disorder, and pulmonary infection. The syndrome treated by Zhenwu Decoction can illustrate the lack of experience of ancient physicians in treating acute heart failure. The description of "trembling and shivering" may be the clinical manifestation of heart failure, which is an upgraded version of "trembling and shaking" treated by Linggui Zhugan Decoction.(1)In terms of diseases, Zhenwu Decoction is suitable for the treatment of acute or chronic heart failure, cardiorenal syndrome, and diuretic resistance. The decoction is especially suitable for treating whole heart failure, acute heart failure, heart failure with reduced ejection fraction, and heart failure with the syndrome of sold and dampness. In addition, it can be used to treat both type Ⅱ and type Ⅳ cardiorenal syndrome.(2)In terms of symptoms, Zhenwu Decoction can be used for treating chest tightness, palpitations, lower limb edema, difficult urination or increased urine output, fear of cold, pale fat tongue with teeth marks, white and slippery tongue fur, and deep or slow pulse.(3)In terms of the pharmacological mechanism, Zhenwu Decoction treats heart failure following the principle of promoting urination, expanding blood vessels, and invigorating heart in modern medicine. Aconiti Lateralis Radix Praparata is the sovereign herb in the formula, with the recommended dosage of 30-60 g. However, arrhythmia may be caused by high doses of Aconiti Lateralis Radix Praparata, which should be used with concern. In addition to Zhenwu Decoction, Shenqi Pills, Renshen Decoction, Wuling Powder, and Fangji Huangqi Decoction with the effect of invigorating spleen, replenishing Qi, warming Yang, and promoting urination can be used in the recovery stage. The therapy of reinforcing Yang was the last choice for critical cases due to the lack of medical conditions, unclear clinical diagnosis in history, which should be treated objectively now.

Connotation of Shenqi Pills based on severe cases in cardiovascular care unit and modern pathophysiological mechanism and application of Shenqi Pills for heart failure, renal failure, cardiorenal syndrome, and diuretic resistance in critical care medicine / 中国中药杂志

Shenqi Pills, first recorded in Essentials from the Golden Cabinet(Jin Kui Yao Lue) from ZHANG Zhong-jing in Han dynasty, have the effect of warming and tonifying the kidney Qi and are mainly used for the treatment of insufficiency of kidney Qi and kidney Yang. According to modern medicine, kidney Qi involves heart function, kidney function, immune function, and so on. The clinical indications of Shenqi Pills include kidney deficiency, abnormal fluid, and abnormal urination, and the last one is classified into little urine, much urine, and dysuria. In clinical settings, Shenqi Pills can be applied for the treatment of heart failure, renal failure, cardiorenal syndrome, and diuretic resistance, as well as endocrine, urological, orthopedic, and other chronic degenerative diseases. Shenqi Pills are ideal prescriptions for the weak constitution and emergency treatment. It is of great value and significance to carry out in-depth research on the connotation of the classic articles by integrating TCM and western medicine based on "pathogenesis combined with pathology and drug properties combined with pharmacology".

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.

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.

Spironolactone to increase natriuresis in congestive heart failure with cardiorenal syndrome.

BACKGROUND: Signs and symptoms of volume overload are the most frequent reason for hospital admission in acute heart failure (AHF). Diuretics are mainstay treatment, but their optimal type and dose regimen remain unclear, especially in patients with cardiorenal syndrome. METHODS: This prospective study aimed to include 80 AHF patients with volume overload and cardiorenal syndrome. Through a 2 × 2 factorial design, patients were randomised towards (1) combinational treatment with acetazolamide and low-dose loop diuretics versus high-dose loop diuretics; and (2) open-label oral spironolactone 25 mg OD given upfront versus at discharge. Here reported are the results of the spironolactone treatment arm after complete follow-up of 34/80 patients (since the study was stopped because of slow recruitment). The primary study end-point was incident hypokalaemia (<3.5 mmol/L) or hyperkalaemia (>5.5 mmol/L). RESULTS: Serum potassium derangements were numerically less frequent in the upfront versus discharge spironolactone group, yet this result was underpowered due to incomplete study recruitment (hyperkalaemia: 6% vs. 11%; hypokalaemia: 13% vs. 28%, respectively; p-value = .270). Natriuresis after 24 h was higher in the upfront vs. discharge spironolactone group (314 ± 142 vs. 200 ± 91 mmol/L, respectively; p-value = .010). Relative change in plasma NT-proBNP level after 72 h was similar among both groups (-16 ± 29% vs. -5 ± 45%, respectively; p value = .393), with no difference in all-cause mortality (p-value = .682) or the combination of all-cause mortality and heart failure readmission (p-value = .799). DISCUSSION: Spironolactone use upfront in AHF patients at high risk for cardiorenal syndrome is safe and increases natriuresis.

Qiliqiangxin Protects against Renal Injury in Rat with Cardiorenal Syndrome Type I through Regulating the Inflammatory and Oxidative Stress Signaling.

Cardiorenal syndrome (CRS) is a frequently encountered clinical condition when the dysfunction of either the heart or kidneys amplifies the failure progression of the other organ. CRS remains a major global health problem. Qiliqiangxin (QLQX) is a traditional Chinese herbs medication, which can improve cardiac function, urine volume, and subjective symptoms in patients with chronic heart failure. In the present study, we aim to investigate the role of QLQX in the treatment of CRS type I and the possible mechanism through establishment of a rat model of myocardial infarction. Rats in CRS-Q group were orally treated with QLQX daily for 2 weeks or 4 weeks, while in sham group and CRS-C group were treated with saline at the same time. Enzyme-linked immunosorbent assay (ELISA) analysis showed that QLQX significantly reduced the levels of angiotensin II (AngII), brain natriuretic peptides (BNP), creatinine (CRE), cystatin C (CysC), tumor necrosis factor (TNF)-α, interleukin (IL)-6, microalbuminuria (MAU), and neutrophil gelatinase-associated lipocalin (NGAL) in plasma induced by myocardial infarction. Western blot analysis showed that QLQX significantly reduced the expressions of AngII, non-phagocytic cell oxidase (NOX)2, and B-cell lymphoma (Bcl)2 associated X protein (Bax), and increased the expressions of Bcl2 and Angiotensin II Type 1 receptor (ATR) in the kidney as compared with the CRS-C group. Fluorescence microscopy showed that the content of reactive oxygen species (ROS) was significantly reduced in the kidney as compared with the CRS-C group. We also examined the apoptosis level in kidney by using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) staining, and the result showed that QLQX significantly reduced the apoptosis level in kidney induced by myocardial infarction. Taken together, we suggest that QLQX may be a potentially effective drug for the treatment of CRS by regulating inflammatory/oxidative stress signaling.

Targeting multiple pathways reduces renal and cardiac fibrosis in rats with subtotal nephrectomy followed by coronary ligation.

AIM: Multiple interacting pathways contribute to progression of renal and cardiac damage in chronic kidney disease followed by chronic heart failure (renocardiac syndrome). We hypothesized that simultaneous pharmacological modulation of critical pathways implicated in renocardiac syndrome would effectively reduce fibrosis in and preserve function of heart and kidney. METHODS: Rats were subjected to subtotal nephrectomy followed 9 weeks later by coronary artery ligation. From week 11 until week 16, rats received vehicle or losartan, or a combination of the NF-kB inhibitor PDTC, the NO donor molsidomine and superoxide dismutase mimetic tempol, or a combination of all four of these plus metoprolol together. At week 16, renal and cardiac structure, function and gene expression were assessed. RESULTS: Individual and combined treatments were similarly effective in limiting cardiac fibrosis and further decline in systolic function. Combined treatment with all five drugs reduced renal fibrosis and CTGF gene expression more effectively than other strategies. Combining all five drugs reduced heart rate, inotropy and mean arterial pressure (MAP). CONCLUSION: Thus, in our model of chronic renocardiac syndrome, combined treatments similarly decreased cardiac fibrosis and stabilized systolic function as losartan alone, perhaps suggesting a dominant role for a single factor such as angiotensin II type 1 (AT1) receptor activation or inflammation in the network of aberrant systems in the heart. However, tubulointerstitial fibrosis was most effectively reduced by a five-drug regimen, pointing to additive effects of multiple pathophysiological pathways in the kidney.

Shenfuqiangxin Capsule inhibits apoptosis through mitogen-activated protein kinase signal pathway in rats with cardio-renal syndrome induced by infrarenal aortic-clamping.

OBJECTIVE: To investigate the effect of Shenfuqiangxin capsule and the underlying mechanism on cardio-renal syndrome (CRS) in rats induced by infrarenal aortic-clamping after renal ischaemia. METHODS: Male Wistar rats underwent infrarenal aortic-clamping after renal ischaemia or sham operation. The surviving CRS rats were divided randomly into three groups: CRS group (CRS + 10 mL·kg(-1)· d(-1) pure water by gavage), SFQX group (CRS + 13.2 g crude drug·kg－ 1·d－ 1 Shenfuqiangxin by gavage), and handleregionpeptide(HRP)group(CRS+10mg/kg HRP by vein). Sham operation rats were given 10 mL·kg－1·d－1 pure water. Treatments were given 8 weeks after surgery, which lasted for 4 weeks. The rats were detected for heart structure and function by transthoracic echocardiography. PPR mRNA was detected by Reverse Transcription Polymerase Chain Reaction (RT-PCR). To determine whether the mitogen-activated protein kinase (MAPK) signal pathway is included in the heart and kidney protective function of Shenfuqiangxin capsule, MAPK related proteins such as posophorylated C-Jun amino terminal kinase (p-JNK), posophorylated extracellular signal-regulated kinase ½ (p-ERK1/2), posophorylated p38 (p-p38) were examined by Western Blot. Apoptosis in heart and kidney tissues were detected by dUTP Nick End Labeling staining. RESULTS: Shenfuqiangxin capsule alleviated myocardial apoptosis and inhibited PRR mRNA expression and p-JNK, p-ERK1/2, p-p38 proteins expression in CRS rats. CONCLUSION: All the results suggest that Shenfuqiangxin capsule improves the injured heart and kidney function maybe through inhibition of MAPK response pathway.

Predictors of erythropoietin use in patients with cardiorenal anaemia syndrome.

OBJECTIVES: Chronic kidney disease (CKD) and anemia are common in patients with heart failure (HF) - these 3 conditions have been coined the Cardiorenal Anemia Sydrome (CRAS). The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI) guidelines do not specifically address patients with CRAS, creating uncertainty in erythropoietin (EPO) prescribing. We sought to determine predictors of EPO use in patients with CRAS. METHODS: We conducted a retrospective cohort study at the Veteran's Affairs Greater Los Angeles Healthcare System (VAGLAHS), a 300+ bed facility that provides primary and tertiary inpatient, and ambulatory care services, between January 1, 2003 to December 31, 2006. A multiple logistic regression model was constructed to identify predictors of EPO use among CRAS patients. KEY FINDINGS: Of 2058 patients with CRAS, 213 (10.3%) were prescribed EPO. There were significant differences in baseline characteristics between the EPO and non-EPO groups. The following predictors were found to be associated with EPO prescription: iron supplementation (odds ratio [OR] 52.70, 95% confidence interval [CI] 11.70-237.46), renal clinic appointment (OR 2.60, 95% CI 1.79-3.76), malignancy (OR 1.52, 95% CI 1.07-2.16) and use of hydralazine/nitrates (OR 1.41, 95% CI 1.03-1.92). There was an inverse association found between EPO prescription and baseline hemoglobin (OR 0.61, 95% CI 0.53-0.70) and eGFR (OR 0.96, 95% CI 0.94-0.97). CONCLUSION: A small proportion of patients eligible for EPO therapy according to guidelines at the time of the study were prescribed the indicated therapy. Markers of declining renal function or those suggesting need for anemia therapy were identified as EPO predictors.

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.

Beyond the cardiorenal anaemia syndrome: recognizing the role of iron deficiency.

Growing awareness that heart failure, renal impairment, and anaemia are frequent co-morbidities which can exacerbate one another in a vicious circle of clinical deterioration has led to the concept of the cardiorenal anaemia syndrome (CRAS). The role of iron deficiency within this complex interplay has been less well examined. Scrutiny of data from the recent FAIR-HF trial raises a new hypothesis: is it time for 'CRAS' to be supplemented with new acronyms such as CRIDS (cardiorenal-iron deficiency syndrome) or even CRAIDS (cardiorenal-anaemia-iron deficiency syndrome)? Iron deficiency occurs frequently in heart failure patients with or without anaemia. It not only impairs oxygen transport through reduced erythropoiesis, but adversely affects oxidative metabolism, cellular energetics, and immune mechanisms, and the synthesis and degradation of complex molecules such as DNA. One large observational study in patients with heart failure found iron deficiency to be an independent predictor of death or urgent heart transplantation (hazard ratio 1.58, 95% confidence interval 1.14-2.17, P = 0.005). In the FAIR-HF trial, i.v. iron therapy was associated with significant improvements in physical functioning in iron-deficient patients with heart failure, even in non-anaemic patients in whom haemoglobin levels did not change following i.v. iron administration. Key questions regarding the use of i.v. iron supplementation in the setting of heart failure merit exploration and could readily be answered by appropriately designed clinical trials. It is to be hoped that these important clinical trials are conducted, to permit a more subtle characterization of the patient's pathological condition and interventional requirements.

Mineral metabolism abnormalities and vitamin D receptor activation in cardiorenal syndromes.

Over the last decade, it has become increasingly clear that the cardiovascular and renal systems are interdependent. Primary disorders of either system have been shown to disturb the other system. As a result, a class of cardiorenal syndromes (CRS) has been identified wherein a vicious cycle is established as an acute/chronic dysfunction of either the kidney or the heart exacerbates the loss of function in the other organ. Progressive loss of kidney function observed in patients with CRS (mostly types 2 and 4) leads to reduced production of calcitriol (active vitamin D) and an imbalance in calcium and phosphorus levels, which are correlated with increased rates of cardiovascular events and mortality. In addition, hypocalcemia can lead to prolonged and excessive secretion of parathyroid hormone (PTH), eventually leading to development of secondary hyperparathyroidism. Therefore, based on this important mechanism of organ damage, one of the major goals of therapy for patients with CRS is to restore regulatory control of PTH. Although administration of calcitriol increases serum calcium levels and reduces PTH levels, it is also associated with elevated serum levels of calcium-phosphorus product. Therefore, compounds that selectively activate vitamin D receptors, potentially reducing calcium × phosphate toxicity, are likely to enhance cardiorenal protection and provide significant clinical benefit.