Anemia is common in patients who have both heart failure and chronic kidney disease, and there is an association between anemia and progression of both diseases. The main causes of anemia are deficient production of erythropoietin (EPO), iron deficiency, and chronic disease with endogenous EPO resistance. EPO has been successfully used for over a decade to treat anemia in patients with chronic kidney disease. Less obvious are the safety and efficacy of EPO treatment in patients with both heart failure and renal disease. Up to 10% of patients receiving EPO are hyporesponsive to therapy and require large doses of the agent. Several mechanisms could explain resistance to endogenous and exogenous EPO. Proinflammatory cytokines antagonize the action of EPO by exerting an inhibitory effect on erythroid progenitor cells and by disrupting iron metabolism (a process in which hepcidin has a central role). EPO resistance might also be caused by inflammation, which has a negative effect on EPO receptors. Furthermore, neocytolysis could have a role. As resistance to exogenous EPO is associated with an increased risk of death, it is important to understand how cardiorenal failure affects EPO production and function.

AimsErythropoietin (EPO) resistance, an important cause of anaemia in patients with heart and renal failure, is associated with increased mortality. The hypothesis of the present study was that exogenous EPO decreases hepcidin levels and that the decrease in hepcidin levels upon EPO treatment is related to the bone marrow response. Methods and resultsIn the EPOCARES trial, patients with renal failure (glomerular filtration rate 20-70 mL/min), heart failure, and anaemia were randomized to receive 50 IU/kg/week EPO (n ¼ 20) or not (n ¼ 13). Haemoglobin (Hb), hepcidin-25, ferritin, reticulocytes, serum transferrin receptor (sTfR), IL-6, and high-sensitivity C-reactive protein were measured at baseline and during treatment. Hepcidin-25 was measured by weak cation exchange chromatography/ matrix assisted laser desorption ionization time-of-flight mass spectrometry. Baseline hepcidin levels were increased compared with a healthy reference population and were inversely correlated with Hb (r 2 ¼ 0.18, P ¼ 0.02), and positively with ferritin (r 2 ¼ 0.51, P , 0.001), but not with renal function, high-sensitivity C-reactive protein or IL-6. Erythropoietin treatment increased reticulocytes (P , 0.001) and sTfR (P , 0.001), and decreased hepcidin (P , 0.001). Baseline hepcidin levels and the magnitude of the decrease in hepcidin correlated with the increase in reticulocytes (r 2 ¼ 0.23, P ¼ 0.03) and sTfR (r 2 ¼ 0.23, P ¼ 0.03) and also with the Hb response after 6 months (r 2 ¼ 0.49, ConclusionIn this group of patients with combined heart and renal failure and anaemia, increased hepcidin levels were associated with markers of iron load and not with markers of inflammation. The (change in) hepcidin levels predicted early and long-term bone marrow response to exogenous EPO. In our group hepcidin seems to reflect iron load and response to EPO rather than inflammation and EPO resistance.--

As melatonin amplitude and melatonin rhythm decreased with advancing renal dysfunction, follow-up research into circadian rhythms in patients with CKD is warranted.

EPO resistance was not associated with RDW. RDW was associated with functional iron availability, erythropoietic activity, and interleukin-6 in anemic patients with CHF and CKD.

We have recently proposed severe cardiorenal syndrome (SCRS), in which cardiac and renal failure mutually amplify progressive failure of both organs. This frequent pathophysiological condition has an extremely poor prognosis. Interactions between inflammation, the renin-angiotensin system, the balance between the nitric oxide and reactive oxygen species and the sympathetic nervous system form the cardiorenal connectors and are cornerstones in the pathophysiology of SCRS. An absolute deficit of erythropoietin (Epo) and decreased sensitivity to Epo in this syndrome both contribute to the development of anemia, which is more pronounced than renal anemia in the absence of heart failure. Besides expression on erythroid progenitor cells, Epo receptors are present in the heart, kidney, and vascular system, in which activation results in antiapoptosis, proliferation, and possibly antioxidation and anti-inflammation. Interestingly, Epo can improve cardiac and renal function. We have therefore reviewed the literature with respect to Epo and the cardiorenal connectors. Indeed, there are indications that Epo can diminish inflammation, reduce renin-angiotensin system activity, and shift the nitric oxide and reactive oxygen species balance toward nitric oxide. Information about Epo and the sympathetic nervous system is scarce. This analysis underscores the relevance of a further understanding of clinical and cellular mechanisms underlying protective effects of Epo, because this will support better treatment of SCRS. heart failure; renal failure; anemia; nitric oxide; reactive oxygen species COEXISTENCE OF RENAL AND cardiac disease is associated with high morbidity and mortality. This pathophysiological condition, in which combined cardiac and renal dysfunction amplifies a progression in the failure of the individual organ, has recently been denoted as severe cardiorenal syndrome (SCRS) (19,20).In patients with declined renal function measured by glomerular filtration rate (GFR), an independent increased risk for cardiovascular events has been found. The hazard ratio for cardiovascular events was 1.4 with a GFR Ͻ60 ml/min and increased with diminished renal function to 2.8 in patients with a GFR Ͻ30 ml/min (99). A 40% higher adjusted risk for adverse cardiovascular outcomes or death was observed in those with relatively minor degrees of renal dysfunction (120). The prevalence of chronic renal failure (CRF) is reportedly high in patients with congestive heart failure (CHF). Furthermore, the prevalence and severity of CRF correlate with the severity of CHF (44, 72). These data support that combined cardiac and renal failure is a profound problem, and a further understanding of the underlying pathophysiological and molecular mechanisms is needed to improve therapy.Our group proposed an interactive network of cardiorenal connectors, i.e., the renin-angiotensin system (RAS), nitric oxide and reactive oxygen species (NO-ROS) balance, the sympathetic nervous system (SNS), and inflammation, as the cornerstones of the pathophysiology o...

The pineal hormone melatonin plays a major role in circadian sleep-wake rhythm. Patients with Chronic Kidney Disease (CKD), especially those who are on hemodialysis, frequently suffer from sleep disturbances. In this review an overview is given of the classification of stages of chronic kidney disease, followed by a presentation of the circadian rhythm disorders in renal disease involving sleep disturbances in relation to melatonin deficiency. The therapeutic benefit of melatonin treatment in sleep disorders related to chronic kidney disease including the controlled trials solving this topic, is described. Furthermore, the beneficial effect of melatonin on blood pressure alterations in CKD states and the protection of melatonin in oxidative stress and inflammation in renal disorders are explored. Finally a hypothetic model is described for the relation between circadian rhythm disorders and CKD.

Purpose Hemoglobin cycling has been reported in hemodialysis patients treated with erythropoiesis-stimulating agents (ESA) and is associated with increased mortality. Information on hemoglobin cycling in Europe is limited. We investigated hemoglobin variability in the Netherlands. Hemodialysis and peritoneal dialysis patients were studied and pre-dialysis patients were enrolled. Methods This observational retrospective study was executed in a Dutch dialysis center. We studied 157 patients from 2005 to 2007: 56 hemodialysis, 12 peritoneal dialysis and 29 pre-dialysis patients, all treated with ESA; and 60 pre-dialysis patients without ESA. Patients were divided on the basis of their pattern of hemoglobin fluctuation around a range of 11–12 g/dL. In dialysis patients, the amount of time that hemoglobin remained within that range was calculated. For all patients, the magnitude of hemoglobin fluctuations was assessed (i.e. the difference between hemoglobin maximum and minimum) and data on ESA dose changes and hospitalizations were collected. Results None of the ESA treated patients had hemoglobin levels stable within the target range over a one-year period. Pre-dialysis patients without ESA also showed variable hemoglobin levels. A stepwise decrease in the magnitudes of hemoglobin fluctuation was observed in the hemodialysis patients, peritoneal dialysis patients, pre-dialysis patients using ESA, and the pre-dialysis patients without ESA, respectively. Conclusion In the Netherlands, hemoglobin variability is common in hemodialysis and peritoneal dialysis patients, but also in pre-dialysis patients. The results of this study warrant further research into the relationship between hemoglobin variability and clinical outcomes.

BackgroundIn patients with chronic heart failure and chronic kidney disease, correction of anemia with erythropoietin‐stimulating agents targeting normal hemoglobin levels is associated with an increased risk of cardiovascular morbidity and mortality. Emerging data suggest a direct effect of erythropoietin on fibroblast growth factor 23 (FGF23), elevated levels of which have been associated with adverse outcomes. We investigate effects of erythropoietin‐stimulating agents in patients with both chronic heart failure and chronic kidney disease focusing on FGF23.Methods and ResultsIn the EPOCARES (Erythropoietin in CardioRenal Syndrome) study, we randomized 56 anemic patients (median age 74 [interquartile range 69–80] years, 66% male) with both chronic heart failure and chronic kidney disease into 3 groups, of which 2 received epoetin beta 50 IU/kg per week for 50 weeks, and the third group served as control. Measurements were performed at baseline and after 2, 26, and 50 weeks. Data were analyzed using linear mixed‐model analysis. After 50 weeks of erythropoietin‐stimulating agent treatment, hematocrit and hemoglobin levels increased. Similarly, C‐terminal FGF23 levels, in contrast to intact FGF23 levels, rose significantly due to erythropoietin‐stimulating agents as compared with the controls. During median follow‐up for 5.7 (2.0–5.7) years, baseline C‐terminal FGF23 levels were independently associated with increased risk of mortality (hazard ratio 2.20; 95% CI, 1.35‐3.59; P=0.002).ConclusionsExogenous erythropoietin increases C‐terminal FGF23 levels markedly over a period of 50 weeks, elevated levels of which, even at baseline, are significantly associated with an increased risk of mortality. The current results, in a randomized trial setting, underline the strong relationship between erythropoietin and FGF23 physiology in patients with chronic heart failure and chronic kidney disease.Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT00356733.