Blood levels of erythropoietin in congestive heart failure and correlation with clinical, hemodynamic, and hormonal profiles

The treatment of chronic anemia in heart failure: a global approach

Chronic anemia is an independent risk factor for mortality in patients with heart failure (HF). Restoring physiological hemoglobin (Hb) levels is essential to increase oxygen transport capacity to tissues and improve cell metabolism as well as physical and cardiac performance. Nutritional deficits and iron deficiency are the major causes of chronic anemia, but other etiologies include chronic kidney disease, inflammatory processes, and unexplained anemia. Hormonal therapy, including erythropoietin (EPO) and anabolic treatment in chronic anemia HF patients, may contribute to improving Hb levels and clinical outcomes. Although preliminary studies showed a beneficial effect of EPO therapy on cardiac efficiency and in HF, more recent studies have not confirmed this positive impact of EPO, alluding to its side effect profile. Physical exercise significantly increases Hb levels and the response of anemia to treatment. In malnourished patients and chronic inflammatory processes, low levels of anabolic hormones, such as testosterone and insulin-like growth factor-1, contribute to the development of chronic anemia. This paper aims to review the effect of nutrition, EPO, anabolic hormones, standard HF treatments, and exercise as regulatory mechanisms of chronic anemia and their cardiovascular consequences in patients with HF.

Hemosiderin Accumulation in Liver Decreases Iron Availability in Tachycardia-Induced Porcine Congestive Heart Failure Model

Despite advances in the management of iron deficiency in heart failure (HF), the mechanisms underlying the effects of treatment remain to be established. Iron distribution and metabolism in HF pathogenesis need to be clarified. We used a porcine tachycardia-induced cardiomyopathy model to find out how HF development influences hepatic and myocardial iron storing, focusing on ferritin, the main iron storage protein. We found that cumulative liver congestion (due to the decrease of heart function) overwhelms its capacity to recycle iron from erythrocytes. As a consequence, iron is trapped in the liver as poorly mobilized hemosiderin. What is more, the ferritin-bound Fe³⁺ (reflecting bioavailable iron stores), and assembled ferritin (reflecting ability to store iron) are decreased in HF progression in the liver. We demonstrate that while HF pigs show iron deficiency indices, erythropoiesis is enhanced. Renin–angiotensin–aldosterone system activation and hepatic hepcidin suppression might indicate stress erythropoiesisinduced in HF. Furthermore, assembled ferritin increases but ferritin-bound Fe³⁺ is reduced in myocardium, indicating that a failing heart increases the iron storage reserve but iron deficiency leads to a drop in myocardial iron stores. Together, HF in pigs leads to down-regulated iron bioavailability and reduced hepatic iron storage making iron unavailable for systemic/cardiac needs.

Proteomic Biomarkers in the Cardiorenal Syndrome: Toward Deciphering Molecular Pathophysiology

Cardiorenal syndrome (CRS) is defined by coexisting heart and renal dysfunctions. Malfunction of 1 organ may cause dysfunction of the other with variable causative disease that defines the type of CRS (1-5). Numerous studies showed that the prevalence of cardiovascular disease is increased in patients with chronic kidney disease (CKD). Similarly, CKD affects a large proportion of patients with heart failure. This overlap between primary heart or primary kidney disease blurs cause-effect inferences of the initiator/target organ. The classical subdivision of CRS in 5 categories does not provide pathophysiological suggestions for targeted intervention. It seems timely to revisit the value of CRS biomarkers in a pathophysiology-centered approach. We systematically reviewed the literature in CRS, which revealed 53 clinical studies describing the use of 44 biomarkers and 4 proteomic panels. All biomarkers are involved in at least one of the CRS comorbidities. Among the pathways affected, inflammation, aberrant glucose metabolism, neurohormonal activation, and oxidative stress are well described. There is growing evidence that fibrosis may be the "cornerstone" that unifies most of the pathways leading to CRS. Formation of excess fibrous connective tissue antedates CRS in many cases. This review highlights that biomarkers reflecting fibrosis may be of substantial clinical value in the early detection, prognostication, and guiding treatment of CRS. Biomarkers detecting changes in collagen turnover in the extracellular matrix of heart and kidney appear able to depict subclinical changes in the fibrotic remodeling of tissues and constitute a promising approach toward personalized intervention in CRS.

Updates on Laboratory Evaluation of Feline Cardiac Diseases

Laboratory tests can be altered in cardiovascular diseases and the investigation of specific tests or biomarkers may provide additional information about myocardial damage. Traditional laboratory tests, such as cell blood count, serum biochemistry, and coagulation, can be useful in investigating patients, but are not specific. However, markers like Troponin and Natriuretic Peptides may possibly furnish further data on myocardium damage and can be used in both studying and monitoring cats with cardiac disease. Moreover, the evaluation of the thyroid profile is very important as hyperthyroid cats concomitant cardiovascular diseases are very common and they can also be a direct consequence of endocrinopathy. The purpose of this manuscript is to provide the widest possible overview of what is present in the literature about the feline clinical pathology of heart diseases through a rational division of the main alterations of traditional tests and biomarkers.

Canine Traditional Laboratory Tests and Cardiac Biomarkers

In small animals, cardiac disease evaluation through laboratory tests can be a challenge. This review will present both historical and updated perspectives on the clinical pathology of cardiac diseases in dogs and demonstrate that laboratory tests are useful tools for the management of patients with cardiac diseases.

High Plasma Erythropoietin Predicts Incident Fractures in Elderly Men with Normal Renal Function: The MrOS Sweden Cohort

Preclinical studies on the role of erythropoietin (EPO) in bone metabolism are contradictory. Regeneration models indicate an anabolic effect on bone healing, whereas models on physiologic bone remodeling indicate a catabolic effect on bone mass. No human studies on EPO and fracture risk are available. It is known that fibroblast growth factor 23 (FGF23) affects bone mineralization and that serum concentration of FGF23 is higher in men with decreased estimated glomerular filtration rate (eGFR). Recently, a direct association between EPO and FGF23 has been shown. We have explored the potential association between EPO and bone mineral density (BMD), fracture risk, and FGF23 in humans. Plasma levels of EPO were analyzed in 999 men (aged 69 to 81 years), participating in the Gothenburg part of the population-based Osteoporotic Fractures in Men (MrOS) study, MrOS Sweden. The mean ± SD EPO was 11.5 ± 9.0 IU/L. Results were stratified by eGFR 60 mL/min. For men with eGFR ≥60 mL/min (n = 728), EPO was associated with age (r = 0.13, p < 0.001), total hip BMD (r = 0.14, p < 0.001), intact (i)FGF23 (r = 0.11, p = 0.004), and osteocalcin (r = -0.09, p = 0.022). The association between total hip BMD and EPO was independent of age, body mass index (BMI), iFGF23, and hemoglobin (beta = 0.019, p < 0.001). During the 10-year follow-up, 164 men had an X-ray-verified fracture, including 117 major osteoporotic fractures (MOF), 39 hip fractures, and 64 vertebral fractures. High EPO was associated with higher risk for incident fractures (hazard ratio [HR] = 1.43 per tertile EPO, 95% confidence interval [CI] 1.35-1.63), MOF (HR = 1.40 per tertile EPO, 95% CI 1.08-1.82), and vertebral fractures (HR = 1.42 per tertile EPO, 95% CI 1.00-2.01) in a fully adjusted Cox regression model. In men with eGFR<60 mL/min, no association was found between EPO and BMD or fracture risk. We here demonstrate that high levels of EPO are associated with increased fracture risk and increased BMD in elderly men with normal renal function. © 2019 American Society for Bone and Mineral Research.

Increased Red Cell Volume Is a Relevant Contributing Factor to an Expanded Blood Volume in Compensated Systolic Chronic Heart Failure

BACKGROUND

In patients with chronic heart failure (CHF), volume overload is usually described as an expansion of plasma volume. Additional red cell volume (RCV) expansion is less commonly recognized. So far, little is known about quantitative differences in blood volume status and its different components in patients with stable CHF compared to healthy controls.

METHODS

This study aimed to quantify blood volume and its constituents, RCV and plasma volume, by using an abbreviated carbon monoxide rebreathing method with particular focus on its primary measure total hemoglobin mass in 47 patients (10 women) with systolic CHF and a left ventricular ejection fraction of 29.0 ± 9.4%. These were compared to an age-matched control group of 84 healthy subjects (44 women) using the same method.

RESULTS

In both absolute and body-surface-area-corrected analysis, hemoglobin mass (446 ± 81 vs 353 ± 64 g/m²) as well as RCV (1293 ± 231 vs 1033 ± 176 mL/m²) were significantly increased in CHF. In addition, significant plasma volume expansion was observed in CHF (2069 ± 400 vs 1750 ± 231 mL/m²) and, in conjunction with RCV, constituted a significantly increased blood volume (3361 ± 574 vs 2783 ± 369 mL/m²). In 66% of patients with compensated CHF, RCV was excessive compared to 14% in the control group.

CONCLUSIONS

An increased RCV is a relevant contributing factor to hypervolemia in stable CHF. This is associated with an increased oxygen-carrying capacity, so it may be regarded as a possible compensatory mechanism for a reduced ejection fraction.

Age-dependent impairment of the erythropoietin response to reduced central venous pressure in HFpEF patients

Despite growing research interest in the pathophysiology of heart failure with preserved ejection fraction (HFpEF), it remains unknown whether central hemodynamic alterations inherently present in this condition do affect blood pressure and blood volume (BV) regulation. The present study sought to determine hemodynamic and endocrine responses to prolonged orthostatic stress in HFpEF patients. Central venous pressure (CVP) assessed via the internal jugular vein (IJV) aspect ratio with ultrasonography, arterial pressure and heart rate were determined at supine rest and during 2 hours of moderate (25-30°) head-up tilt (HUT) in 18 stable HFpEF patients (71.2 ± 7.3 years), 14 elderly (EC), and 10 young (YC) healthy controls. Parallel endocrine measurements comprised main BV-regulating hormones: pro-atrial natriuretic peptide, copeptin, aldosterone, and erythropoietin (EPO). At supine rest, the IJV aspect ratio was higher (>30%) in HFpEF patients compared with EC and YC, while mean arterial pressure was elevated in HFpEF patients (98.0 ± 13.1 mm Hg) and EC (95.6 ± 8.3 mm Hg) versus YC (87.3 ± 5.0 mm Hg) (P < 0.05). HUT increased heart rate (+10%) and reduced the IJV aspect ratio (-52%), with similar hemodynamic effects in all groups (P for interaction ≥ 0.322). The analysis of endocrine responses to HUT revealed a group×time interaction for circulating EPO, which was increased in YC (+10%) but remained unaltered in HFpEF patients and EC. The EPO response to a given reduction in CVP is similarly impaired in HFpEF patients and elderly controls, suggesting an age-dependent dissociation of EPO production from hemodynamic regulation in the HFpEF condition.

Erythropoietin response to anaemia in heart failure

Background

Despite multiple factors correlating with the high prevalence of anaemia in heart failure, the prevailing mechanisms have yet to be established. The purpose of this study is to systematically review the literature and determine whether low circulating haemoglobin is primarily underlain by erythropoietin resistance or defective production in heart failure.

Design and methods

We conducted a systematic search of MEDLINE since its inception until May 2017 for articles reporting erythropoietin and haemoglobin concentrations in heart failure patients not treated with erythropoietin-stimulating agents. The primary outcome was the mean difference in observed/predicted (O/P) erythropoietin ratio between heart failure patients and normal reference values. Meta-regression analyses assessed the influence of potential moderating factors.

Results

Forty-one studies were included after systematic review, comprising a total of 3137 stable heart failure patients with mean age and left ventricular ejection fraction ranging from 52 years to 80 years and 21% to 59%. The O/P erythropoietin ratio was below reference values in 24 of 25 studies in anaemic heart failure patients ( n = 1094, range = 0.49–1.05), whereas only one out of 16 studies in non-anaemic heart failure patients presented a low O/P erythropoietin ratio ( n = 2043, range = 0.91–1.97). In studies comparing anaemic versus non-anaemic heart failure patients ( n = 1531), the mean O/P erythropoietin ratio was consistently reduced in anaemic heart failure patients (mean difference = –0.68, 95% confidence interval = −0.78, −0.57; p < 0.001). In meta-regression, the O/P erythropoietin ratio was negatively associated with age, female sex, left ventricular ejection fraction, inflammation and disease severity.

Conclusion

Anaemia in heart failure is overwhelmingly characterized by impaired erythropoietin production, which is exacerbated with age, female sex, left ventricular ejection fraction, inflammation and disease severity.

[Epidemiological features of cardiorenal syndrome: a study of 36 cases in the Cardiology Department in Dakar]

INTRODUCTION

Cardiorenal syndrome (CRS) is a pathophysiologic disorder of the heart and the kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction of the other. In Africa, particularly in Senegal, the incidence of cardiorenal syndrome is not accurately known. This study aimed to assess the prevalence of CRS in the Cardiology Department.

METHODS

We conducted a retrospective study including all patients with heart failure associated with alteration of renal function, hospitalized in the Cardiology Department between April 2010 and April 2011. Data were analyzed with the statistical software Epi-Info 3.5.3.

RESULTS

36 patients were included in the study. The prevalence rate was 3.7% with male predominance (sex-ratio 1.77) and an average age of 56.9 years [30-92]. Patients' medical history was dominated by high blood pressure (52.77%) and diabetes (19.4%). The main etiologies were hypertensive cardiomyopathy (39%) and coronary heart disease (19.44%). The symptomatology was dominated by dyspnoea (69.4%) and edema (50%). 17 patients had anemia. The mean measured clearance (MDRD) was 46 ml/min. Doppler echocardiography showed mainly kinetic disorders (89.3%) and left ventricular systolic dysfunction (71%). The three renal ultrasound examinations were normal. Six deaths (16.7%) were recorded.

CONCLUSION

Cardiorenal syndrome is a reality and marks a turning point in the evolution of heart and kidney diseases. In Senegal, its prevalence in the Cardiology Department is low. Prospective multicentric studies should be conducted in order to better evaluate this syndrome in Senegal.

Prevalence and Prognosis of Anemia in Dogs with Degenerative Mitral Valve Disease

In humans, heart failure (HF) and renal insufficiency (RI) have negative reciprocal effects, and anemia can exacerbate their progression. In this retrospective study, the prevalence and prognostic significance of anemia in 114 dogs with degenerative mitral valve disease (DMVD) was investigated. Pretreatment clinical parameters, prevalence of anemia and azotemia, and survival time were analyzed in relation to HF severity. The prevalence of anemia was highest in dogs with the modified New York Heart Association (NYHA) class IV HF (33.3%), followed by classes III (15.2%) and II (0%; p < 0.001). The presence of anemia was associated with HF severity and blood creatinine > 1.6 mg/dL (both p < 0.001). Anemic dogs had a shorter median survival [13 months; 95% confidence interval (CI): 0.7-19.1] than nonanemic dogs (28 months; 95% CI: 15.3-40.7; p < .001). NYHA class IV (hazard ratio (HR): 3.1, 95% CI: 2.2-4.3; p < 0.001), left atrium/aorta ratio > 1.7 (HR: 2.7, 95% CI: 1.7-4.2; p = 0.001), and presence of anemia (HR: 1.43, 95% CI: 1.1-1.9; p = 0.004) emerged as predictors of mortality. A cardiorenal-anemia syndrome-like triangle was observed and anemia was a prognostic factor for survival in dogs with DMVD.

Association of Serum Erythropoietin With Cardiovascular Events, Kidney Function Decline, and Mortality: The Health Aging and Body Composition Study

BACKGROUND

Studies suggest that in patients with heart failure (HF), high serum erythropoietin is associated with risk of recurrent HF and mortality. Trials of erythropoietin-stimulating agents in persons with kidney disease have also suggested an increased incidence of adverse clinical events. No large studies of which we are aware have evaluated the association of endogenous erythropoietin levels with clinical outcomes in the community-living older adults.

METHODS AND RESULTS

Erythropoietin concentration was measured in 2488 participants aged 70-79 years in the Health, Aging and Body Composition Study. Associations of erythropoietin with incident HF, coronary heart disease, stroke, mortality, and ≥ 30% decline in estimated glomerular filtration rate were examined using Cox proportional hazards and logistic regression over 10.7 years of follow-up. Mean (SD) age was 75 (3) years and median (quartile 1, quartile 3) erythropoietin was 12.3 (9.0, 17.2) mIU/mL. There were 503 incident HF events, and each doubling of serum erythropoietin was associated with a 25% increased risk of incident HF 1.25 (95% confidence interval 1.13, 1.48) after adjusting for demographics, prevalent cardiovascular disease, cardiovascular disease risk factors, kidney function, and serum hemoglobin. There was no interaction of serum erythropoietin with chronic kidney disease or anemia (P > 0.50). There were 330 incident coronary heart disease events, 161 strokes, 1112 deaths, and 698 outcomes of ≥ 30% decline in estimated glomerular filtration rate. Serum erythropoietin was not significantly associated with these outcomes.

CONCLUSIONS

Higher levels of endogenous erythropoietin are associated with incident HF in older adults. Studies need to elucidate the mechanisms through which endogenous erythropoietin levels associate with specific outcomes.

Physiology of the Renal Interstitium

Long overlooked as the virtual compartment and then strictly characterized through descriptive morphologic analysis, the renal interstitium has finally been associated with function. With identification of interstitial renin- and erythropoietin-producing cells, the most prominent endocrine functions of the kidney have now been attributed to the renal interstitium. This article reviews the functional role of renal interstitium.

The role of erythropoietin stimulating agents in anemic patients with heart failure: solved and unresolved questions

Anemia is a common finding in congestive heart failure (CHF) and is associated with an increased mortality and morbidity. Several conditions can cause depression of erythroid progenitor cells: reduction of iron absorption and reuptake, decreased bone marrow activity, reduced endogenous erythropoietin production, and chronic inflammatory state. Anemia's etiology in CHF is complex and partially understood; it involves several systems including impaired hemodynamic condition, reduced kidney and bone perfusion, increased inflammatory activity, and neurohormonal overdrive. The use of erythropoiesis stimulating agents (ESAs) such as erythropoietin and its derivatives is recently debated; the last interventional trial seems to demonstrate a neutral or negative effect in the active arm with darbepoetin treatment. The current data is opposite to many single blind studies and previous meta-analysis showing an improvement in quality of life, New York Heart Association class, and exercise tolerance using ESA therapy. These contrasting data raise several concerns regarding the target of hemoglobin levels needing intervention, the exact anemia classification and categorization, and the standardization of hematocrit cutoffs. Some cardiac and systemic conditions (ie, hypertension, atrial fibrillation, prothrombotic status) may predispose to adverse events, and ESA administration should be avoided. To prevent the negative effects, high-dosage and chronic administration should be avoided. Clarification of these items could probably identify patients that may benefit from additional iron or ESA treatment. In this review, we discuss the interventional trials made in anemic heart failure patients, the underlying mechanism of anemia in CHF, and the potential role of ESA in this setting.

Erythropoietin in cardiac disease: effective or harmful?

Discovered as the primary regulator of erythropoiesis, erythropoietin (EPO) is involved in a broad variety of processes that play a major role in cardiovascular diseases. In particular, the antiapoptotic and pro-angiogenic properties of EPO have prompted a growing interest in the use of EPO for the treatment of myocardial infarction and heart failure. In a variety of myocardial ischemic injury animal models, EPO administration has been shown to acutely reduce infarct size, thereby preserving ventricular function. In addition, cardiac long-term effects of EPO, such as prevention of ventricular remodeling and heart failure, have been described. In recent years, several trials have tested the effects of recombinant human erythropoietin (rhEPO) administration in patients with myocardial infarction and chronic heart failure, in the attempt to translate the cardioprotection found in experimental models to human patients. In view of the generally controversial findings, in this updated review we provide an overview of the results of the most recent trials that investigated the role of erythropoiesis-stimulating agents (ESAs), including rhEPO and its analogue darbepoetin, in the treatment of acute myocardial infarction and heart failure. The problems related to safety and tolerability of ESA therapy are also discussed. Our analysis of the available literature demonstrates that the results of clinical studies in patients with cardiac disease are not uniform and the conclusions are contradictory. Further larger prospective studies are required to test clinical efficacy and safety of EPO.

Adaptive servo-ventilation therapy improves long-term prognosis in heart failure patients with anemia and sleep-disordered breathing

Sleep disordered breathing (SDB) and anemia influences the progression of chronic heart failure (CHF). Adaptive servo-ventilation (ASV) is an effective therapeutic device for treatment of CHF, however, the impacts of ASV on CHF patients with or without anemia remain unclear.A total of 139 patients with CHF and SDB were divided into two groups: those treated with ASV (n = 53) and without ASV (n = 86). All patients were prospectively followed after discharge with the endpoints of cardiac death or progressive heart failure requiring rehospitalization. There were 65 patients (47%) with anemia among all subjects. The apnea hypopnea index was improved, and plasma BNP and high sensitive C-reactive protein levels were decreased in both groups with and without anemia by ASV therapy. The Kaplan-Meier survival curve demonstrated that the cardiac event-free rate in patients with ASV was significantly higher than in those without ASV in the anemia group (P = 0.008). However, in the non-anemia group, the cardiac event-free rate was similarly high in patients both with and without ASV (P = 0.664). Multivariate Cox proportional hazard analysis demonstrated that ASV use was an independent predictor of cardiac events in the anemia group (P = 0.0308), but not in the non-anemia group.ASV treatment for CHF and SDB has more favorable impacts in patients with anemia than in those without anemia.

The role of erythropoietin in myocardial protection: potential mechanisms and applications

The glycoprotein erythropoietin was originally discovered as a principal regulator that promotes the survival, proliferation and differentiation of erythroid progenitor cells. Despite potentially detrimental effects, such as increased blood pressure and hyperviscosity, recombinant human erythropoietin has been demonstrated to be a safe drug, as millions of anemia sufferers have received it over the last decade as a form of treatment. Recently, erythropoietin receptors have been discovered in a variety of tissues, including the cardiovascular system, and erythropoietin has been demonstrated to have a beneficial effect in congestive heart failure patients with anemia. The purpose of this review is to summarize the pleiotropic cardioprotective effects of erythropoietin in the cardiovascular system and to evaluate its potential role as a biomarker in these disorders.

IRON-HF study: a randomized trial to assess the effects of iron in heart failure patients with anemia

BACKGROUND

Anemia in heart failure patients and has been associated with increased morbi-mortality. Previous studies have treated anemia in heart failure patients with either erythropoietin alone or combination of erythropoietin and intravenous (i.v.) iron. However, the effect of i.v. or oral (p.o.) iron supplementation alone in heart failure patients with anemia was virtually unknown.

AIM

To compare, in a double-blind design, the effects of i.v. iron versus p.o. iron in anemic heart failure patients.

METHODS

IRON-HF study was a multicenter, investigator initiated, randomized, double-blind, placebo controlled trial that enrolled anemic heart failure patients with preserved renal function, low transferrin saturation (TSat) and low-to-moderately elevated ferritin levels. Interventions were Iron Sucrose i.v. 200 mg, once a week, for 5 weeks, ferrous sulfate 200 mg p.o. TID, for 8 weeks, or placebo. Primary endpoint was variation of peak oxygen consumption (peak VO2) assessed by ergospirometry over 3 month follow-up.

RESULTS

Eighteen patients had full follow-up data. There was an increment of 3.5 ml/kg/min in peak VO2 in the i.v. iron group. There was no increment in peak VO2 in the p.o. iron group. Patients' ferritin and TSat increased significantly in both treated groups. Hemoglobin increased similarly in all groups.

CONCLUSION

I.v. iron seems to be superior in improving functional capacity of heart failure patients. However, correction of anemia seems to be at least similar between p.o. iron and i.v. iron supplementation.

Repeated assessment of physical biomeasures or blood biomarkers for the definition of volume status and cardiac loading in LVSD

The application of biomarker technology can be usefully implemented in areas where current techniques are inadequate and where a clinical issue, which affects outcome, can be defined. The definition of the loading status of the heart where there is pre-existent impairment of contractile function is a key target. Heart failure is a complex clinical presentation with many varied etiologies, but at the essence of its successful management is the reliable definition of cardiac volume loading. Traditional and many current technological measures are applied to define this relationship, yet their accuracy and performance in individual patients is either basically inadequate or poorly understood and applied. There is a wide range of both physical measurements and blood biomarkers that can be considered to better define this key issue in patients with ventricular systolic impairment. Their performance is considered in detail in this review.

Erythropoietin resistance contributes to anaemia in chronic heart failure and relates to aberrant JAK-STAT signal transduction

BACKGROUND

Chronic heart failure (CHF) patients are frequently anaemic despite elevated endogenous erythropoietin (Epo) levels. We tested the hypothesis that this might be due to Epo resistance and investigated whether any defects apparent were due to Epo receptor (EpoR) downregulation and/or impaired Epo-induced signal transduction.

METHODS

We studied 28 CHF patients (age 64 ± 10 yrs, LVEF 29 ± 9%, 89% male) and 12 healthy controls (65 ± 11 yrs, 75% male). Circulating erythroid progenitors (BFU-E) were cultured with 0, 1, 3 and 9 U/mL Epo. Circulating erythroblast surface EpoR and intracellular phosphorylated Signal Transducer and Activator of Transcription (phosphoSTAT)-5 expression were determined by flow cytometry.

RESULTS

Whilst BFU-E from control and non-anaemic subjects required only 3 U/mL Epo to significantly increase their numbers from baseline (1 U/mL), those from anaemic patients required 9 U/mL Epo. Lower Epo sensitivities related to higher interleukin-6 (r=-0.41, P=0.01) and soluble tumour necrosis factor receptor 2 (r=-0.38, P=0.02) levels. EpoR-positive cells were more abundant in anaemic patients (P<0.001). Although erythroblasts from anaemic patients exhibited higher baseline EpoR and phosphoSTAT5 expression (all P<0.05), Epo stimulation triggered significant increases in phosphoSTAT5 levels only in erythroblasts from control subjects and not in those from anaemic patients.

CONCLUSION

The responsiveness of erythroid cells to Epo is diminished in anaemic CHF patients. This is not due to EpoR downregulation but relates to a profound blunting of Epo-induced JAK-STAT signalling. Whilst residual Epo sensitivity can be exploited clinically with erythropoietic agents, targeting the mechanisms underlying Epo resistance in CHF may provide greater efficacy.

Perspectives for the treatment of anemia in heart failure: is there a role for vasopressin antagonists?

Anemia is an independent predictor of mortality in congestive heart failure patients. Recent studies have recognized that dilutional anemia is highly prevalent in this population. However, the implications for treatment have not been comprehensively elucidated. In this regard, arginine-vasopressin antagonists, by increasing aquaresis, may be an attractive treatment option. Nevertheless, only indirect evidence supports the hypothesis that arginine-vasopressin antagonists may be useful in the treatment of congestive heart failure anemia. Therefore, future clinical research should explore the role of arginine-vasopressin pathway activation in determining dilutional anemia and, ultimately, assess it as a therapeutic target.

Advanced heart failure and nocturnal hypoxaemia due to central sleep apnoea are associated with increased serum erythropoietin

AIMS

Central sleep apnoea (CSA) and increased serum erythropoietin (EPO) concentration have each been associated with adverse prognosis in heart failure (HF) patients. The aim of this study was to examine the relationship between nocturnal hypoxaemia due to CSA and the serum EPO concentration in patients with HF.

METHODS AND RESULTS

Heart failure subjects (n = 33) and healthy controls (n = 18) underwent polysomnography (PSG) for diagnosis of CSA and identification and quantification of hypoxaemia. Blood collection for measurement of EPO was performed immediately post-PSG. For the analysis, HF subjects were dichotomized into subgroups defined by the presence or absence of CSA and by HF severity. Multivariate analyses were performed to evaluate the relationships of hypoxaemia and advanced HF to EPO concentration. Mean EPO concentration was 62% higher for HF subjects with CSA than for healthy controls (P = 0.004). The magnitude of nocturnal hypoxaemia was significantly and positively related to EPO concentration (r = 0.45, P = 0.02). Advanced HF was also significantly and positively related to EPO concentration (r = 0.43, P = 0.02). On multivariate analysis, the presence of combined nocturnal hypoxaemia and advanced HF yielded greater correlation to EPO concentration than either factor alone (r = 0.57, P = 0.04 and P = 0.05, respectively). Linear regression demonstrated that the combination of New York Heart Association Class and CSA was strongly associated with EPO concentration (P < 0.0001).

CONCLUSION

In non-anaemic HF patients, advanced HF and hypoxaemia due to CSA may each be independently associated with increased serum EPO concentration.

Improving prognosis estimation in patients with heart failure and the cardiorenal syndrome

The coexistence of heart failure and renal dysfunction constitutes the “cardiorenal syndrome” which is increasingly recognized as a marker of poor prognosis. Patients with cardiorenal dysfunction constitute a large and heterogeneous group where individuals can have markedly different outcomes and disease courses. Thus, the determination of prognosis in this high risk group of patients may pose challenges for clinicians and for researchers alike. In this paper, we discuss the cardiorenal syndrome as it pertains to the patient with heart failure and considerations for further refining prognosis and outcomes in patients with heart failure and renal dysfunction. Conventional assessments of left ventricular function, renal clearance, and functional status can be complemented with identification of coexistent comorbidities, medication needs, microalbuminuria, anemia, biomarker levels, and pulmonary pressures to derive additional prognostic data that can aid management and provide future research directions for this challenging patient group.

Prediction of long-term survival in chronic heart failure by multiple biomarker assessment: a 15-year prospective follow-up study

BACKGROUND

In chronic heart failure (CHF), several plasma biomarkers identify subjects at risk of death over the midterm. However, their long-term predictive value in the context of other candidate predictors has never been assessed. This information may prove valuable in the management of a chronic disease with a long natural history, as CHF is today.

HYPOTHESIS

We aimed to assess the very-long-term prognostic power of a set of biomarkers to identify CHF patients at highest risk for all-cause mortality.

METHODS

A group of 106 consecutive outpatients with CHF (85 male and 21 female, median age 56 y) was followed for 15 years. Echocardiographic tracings and blood samples were collected at study entry to evaluate cardiac function, plasma atrial natriuretic peptide (ANP), aldosterone, and erythropoietin, and plasma renin activity. The relationships between biomarkers, clinical and echocardiographic variables, and mortality were assessed.

RESULTS

After 15 years, 86 of the 106 patients (81%) had died. Multivariate analysis showed that ANP was the best independent predictor of survival over several clinical, echocardiographic, and humoral variables (hazard ratio: 5.62, 95% confidence interval: 3.37-9.39, P < 0.001 for plasma levels < median value of 71 pg/mL). Plasma renin activity and erythropoietin provided prognostic information in univariate analysis, but lost their predictive power when adjusted for covariates.

CONCLUSIONS

The present study represents the longest available follow-up of patients with CHF evaluating the prognostic power of multiple biomarkers. It shows that a simple assessment of plasma ANP levels is the strongest long-term predictor of death in all stages of heart failure.

Effect of erythropoietin levels on mortality in old age: the Leiden 85-plus Study

BACKGROUND

The production of erythropoietin is triggered by impaired oxygen delivery to the kidney, either because of anemia or hypoxemia. High erythropoietin levels have been shown to predict the risk of death among patients with chronic heart failure. We investigated the prognostic value of elevated erythropoietin levels on mortality among very elderly people in the general population.

METHODS

The Leiden 85-plus Study is a population-based prospective follow-up study involving 599 people aged 85 years in Leiden, the Netherlands, enrolled between September 1997 and September 1999. Erythropoietin levels were determined at age 86. For this analysis, we included 428 participants with a creatinine clearance of at least 30 mL/min. Mortality data, recorded until Feb. 1, 2008, were obtained from the municipal registry.

RESULTS

During follow-up, 324 (75.7%) participants died. Compared with participants whose erythropoietin levels were in the lowest tertile (reference group), those whose levels were in the middle tertile had a 25% increased risk of death (hazard ratio [HR] 1.25, 95% confidence interval [CI] 0.95-1.64), and those whose levels were in the highest tertile had a 73% increased risk (HR 1.73, 95% CI 1.32-2.26) (p value for trend < 0.01). The association between erythropoietin levels and mortality remained largely unchanged after we adjusted for sex, creatinine clearance, hemoglobin level, comorbidity, smoking status and C-reactive protein level, and was similar for deaths from cardiovascular and noncardiovascular causes.

INTERPRETATION

Among people aged 85 years and older, elevated erythropoietin levels were associated with an increased risk of death, independent of hemoglobin levels.

Erythropoietin and the heart: facts and perspectives

EPO (erythropoietin) has long been identified as a primary regulator of erythropoiesis. Subsequently, EPO has been recognized as playing a role in a broad variety of processes in cardiovascular pathophysiology. In particular, the tight interactions of EPO with the nitric oxide pathway, apoptosis, ischaemia, cell proliferation and platelet activation appear of great interest. Although enhanced EPO synthesis is viewed as an appropriate compensatory mechanism in the cardio-renal syndrome, which features CHF (congestive heart failure) and CRF (chronic renal failure), maladaptative excessive EPO synthesis in the advanced stages of these diseases appears to be predictive of higher mortality. Clinical trials based on the use of EPO in both heart and renal failure have so far produced contradictory results, whereas treatment targeted to restore low Hb levels appears rational and is supported by regulatory authorities. New areas for therapeutic use of EPO, such as acute coronary syndromes, are under investigation, and they are discussed in the present review together with other clinical applications in cardiovascular diseases. The revisited concept of a potential use of endogenous EPO levels as a predictor of CHF severity, as well as in the monitoring of responses to treatment, deserves appropriate investigation, as this may identify EPO as a useful biomarker in the clinical management of cardiovascular diseases.

The role of the renin-angiotensin system in the regulation of erythropoiesis

The renin-angiotensin system is the major regulator of blood pressure by virtue of controlling vascular resistance and plasma volume. Much less recognition exists for the role of the renin-angiotensin system in regulating erythropoiesis, a biological function critical for oxygen delivery to tissues. In this review, we present evidence that angiotensin II (Ang II) is a physiologically important regulator of erythropoiesis with 2 key actions. First, Ang II is a growth factor of erythroid progenitors and, in cooperation with erythropoietin, increases red blood cell mass. Second, Ang II acts as an erythropoietin secretagogue to maintain increased erythropoietin levels despite increments in hematocrit. Among a multitude of physiologic and pathophysiologic implications, these lines of evidence provide an explanation for the effect of angiotensin-converting enzyme inhibitors and Ang II type 1 receptor blockers to decrease hematocrit or cause anemia in various clinical conditions.

Managing anemia in patients with chronic heart failure: what do we know?

Anemia is common in patients with chronic heart failure (HF) with an incidence ranging from 4% to 55% depending on the studied population. Several studies have highlighted that the prevalence of anemia increases with worsening heart failure as reflected by New York Heart Association classification. Additionally, several epidemiological studies have highlighted its role as a prognostic marker, linking it to worse outcomes including; malnutrition, increased hospitalizations, refractory heart failure and death. The pathophysiology of anemia is multifactorial and related to various factors including; hemodilution, iron losses from anti-platelet drugs, activation of the inflammatory cascade, urinary losses of erythropoietin and associated renal insufficiency. There are a host of epidemiological studies examining HF outcomes and anemia, but only a few randomized trials addressing this issue. The purpose of this article is to review the literature that examines the interrelationship of anemia and congestive HF, analyzing its etiology, impact on outcomes and also the role of associated kidney disease as well as cardiorenal syndrome both as a marker of morbidity and mortality.

Anemia in heart failure: pathophysiologic insights and treatment options

Anemia has been recognized as a very common and serious comorbidity in heart failure, with a prevalence ranging from 10 to 79%, depending on diagnostic definition, disease severity and patient characteristics. A clear association of anemia with worse prognosis has been confirmed in multiple heart failure trials. This finding has recently triggered intense scrutiny in order to identify the underlying pathophysiology and the best treatment options. Etiology is multifactorial, with iron deficiency and cytokine activation (anemia of chronic disease) playing the most important roles. Treatment is aimed at not only restoring hemoglobin values back to normal, but also at improving the patient's symptoms, functional capacity and hopefully the outcome. Iron supplementation and erythropoietin-stimulating agents have been used for this purpose, either alone or in combination. In this review, the recent advances in elucidating the mechanisms leading to anemia in the setting of heart failure are presented and the evidence supporting the use of different treatment approaches are discussed.

Erythropoietin during hypoglycaemia in type 1 diabetes: relation to basal renin-angiotensin system activity and cognitive function

AIMS

Preservation of cognitive function during hypoglycaemic episodes is crucial for patients with insulin-treated diabetes to avoid severe hypoglycaemic events. Erythropoietin has neuroprotective potential. However, the role of erythropoietin during hypoglycaemia is unclear. The aim of the study was to explore plasma erythropoietin response to hypoglycaemia and the relationship to basal renin-angiotensin system (RAS) activity and cognitive function.

METHODS

We performed a single-blinded, controlled, cross-over study with induced hypoglycaemia or maintained glycaemic level. Nine patients with type 1 diabetes with high and nine with low activity in RAS were studied. Hypoglycaemia was induced using a standardized insulin-infusion.

RESULTS

Overall, erythropoietin concentrations increased during hypoglycaemia. In the high RAS group erythropoietin rose 29% (p=0.032) whereas no significant response was observed in the low RAS group (7% increment; p=0.43). Independently, both hypoglycaemia and high RAS activity were associated with higher levels of erythropoietin (p=0.02 and 0.04, respectively). Low plasma erythropoietin at baseline was associated with poorer cognitive performance during hypoglycaemia.

CONCLUSIONS

Hypoglycaemia triggers a rise in plasma erythropoietin in patients with type 1 diabetes. The response is influenced by basal RAS activity. Erythropoietin may carry a neuroprotective potential during hypoglycaemia.

Erythropoietin levels in heart failure after an acute myocardial infarction: determinants, prognostic value, and the effects of captopril versus losartan

BACKGROUND

In patients with chronic heart failure, erythropoietin (Epo) levels are increased and related to a poor prognosis. Furthermore, Epo levels in these patients show a weak correlation with hemoglobin levels.

METHODS

This is a retrospective analysis of a subgroup of the OPTIMAAL (Optimal Trial in Myocardial Infarction with the Angiotensin II Antagonist Losartan) trial in which serum Epo levels were measured at baseline, at 1 month, and at 1 and 2 years in 224 patients with an acute myocardial infarction complicated by signs or symptoms of heart failure. We investigated the determinants and the prognostic role of elevated Epo levels in these patients, and we studied the change in Epo levels by either captopril or losartan.

RESULTS

The correlation between Epo and hemoglobin at baseline (r = 0.348, P < .001) and after 1 month (r = 0.272, P < .001) disappeared after 1 year of follow up (r = 0.129, P = .102). At 1 year, C-reactive protein was the only factor associated with Epo levels. Higher Epo levels at baseline were independently related to a higher mortality during 2 years of follow-up (hazard ratio 2.84, P = .014). In the captopril group, logEpo levels decreased from 1.19 (+/-0.26) to 0.95 (+/-0.20) mIU/mL, and in the losartan group from 1.19 (+/-0.27) to 1.01 (+/-0.17) mIU/mL (P = .036 between groups).

CONCLUSION

In this substudy of the OPTIMAAL trial, the correlation between Epo and hemoglobin disappeared in early post-acute myocardial infarction heart failure patients. Furthermore, elevated Epo levels at baseline predicted increased mortality.

Darbepoetin-alpha prevents progressive left ventricular dysfunction and remodeling in nonanemic dogs with heart failure

In anemic patients with heart failure (HF), erythropoietin-type drugs can elicit clinical improvement. This study examined the effects of chronic monotherapy with darbepoetin-alpha (DARB) on left ventricular (LV) function and remodeling in nonanemic dogs with advanced HF. HF [LV ejection fraction (EF) approximately 25%] was produced in 14 dogs by intracoronary microembolizations. Dogs were randomized to once a week subcutaneous injection of DARB (1.0 microg/kg, n=7) or to no therapy (HF, n=7). All procedures were performed during cardiac catheterization under general anesthesia and under sterile conditions. LV end-diastolic volume (EDV), end-systolic volume (ESV), and EF were measured before the initiation of therapy and at the end of 3 mo of therapy. mRNA and protein expression of caspase-3, hypoxia inducible factor-1alpha, and the bone marrow-derived stem cell marker c-Kit were determined in LV tissue. In HF dogs, EDV and ESV increased and EF decreased after 3 mo of followup. Treatment with DARB prevented the increase in EDV, decreased ESV, and increased EF. DARB therapy also normalized the expression of HIF-1alpha and active caspase-3 and enhanced the expression of c-Kit. We conclude that chronic monotherapy with DARB prevents progressive LV dysfunction and dilation in nonanemic dogs with advanced HF. These results suggest that DARB elicits beneficial effects in HF that are independent of the presence of anemia.

Anemia and chronic heart failure implications and treatment options

Anemia is a common comorbidity in patients with heart failure and is associated with worse long-term outcomes. Although the cause of anemia in heart failure is unclear, the weight of evidence suggests that renal dysfunction, along with neurohormonal and proinflammatory cytokine activation in heart failure, favors the development of anemia of chronic disease, with defective iron utilization, inappropriate erythropoietin production, and depressed bone marrow function. Similarly, the mechanisms by which anemia worsens heart failure outcomes are unknown but may be related to increased myocardial workload. If anemia is a mediator and not just a marker of poor outcomes, correcting anemia could become an important and novel therapeutic target to improve long-term outcomes in such patients. Indeed, several small-sized studies have shown the beneficial effects of empirically treating anemia in heart failure patients with recombinant erythropoietin and intravenous iron. However, the ideal threshold at which therapy should be initiated and the extent of correction considered safe and desirable in the individual patient with heart failure need to be known. These issues become more important because of increasing safety concerns that recombinant erythropoietin therapy for treating anemia may be associated with adverse cardiovascular outcomes in patients with chronic kidney disease and may worsen cancer in patients receiving chemotherapy to treat various types of cancer. Therefore, further prospectively designed studies are required to address some of these questions. Fortunately, 2 large mortality morbidity trials, TREAT (Trial to Reduce Cardiovascular Events with Aranesp Therapy) in patients with chronic kidney disease and RED-HF (Reduction of Events with Darbepoetin alfa in Heart Failure) in heart failure patients, are in progress and are likely to provide definitive answers.

Traditional and novel approaches to management of heart failure: successes and failures

Although considerable progress has been made in the pharmacologic and device management of chronic heart failure in recent decades, heart failure patients continue to remain symptomatic, with high hospitalization and mortality rates. A number of novel agents, including endothelin antagonists and tumor-necrosis factor blockers, have recently failed to improve the clinical outcomes of patients with heart failure. Have we reached a ceiling in preventing the progression of the disease? This article reviews successes and late-stage clinical trial disappointments in the treatment of patients with heart failure. Furthermore, the article discusses how agents that have beneficial effects in heart failure also generally attenuate or reverse ventricular remodeling, whereas the newer agents that have failed to improve clinical outcomes either had no effect on remodeling or have been associated with adverse remodeling.

Cardiorenal anemia syndrome: do erythropoietin and iron therapy have a place in the treatment of heart failure?

The cardiorenal anemia syndrome in congestive heart failure (CHF) is an independent risk factor for vascular morbidity and mortality. Several factors play a role in the pathogenesis of anemia in CHF, including inflammation, impaired renal function, use of certain antihypertensive or cardioprotective agents, and gastrointestinal or urinary losses of essential hemopoietic factors. Several trials evaluated the effects of administering erythropoietin (EPO) and/or iron to patients with CHF. Even though most of them were uncontrolled studies, their results suggest that EPO treatment might be beneficial in CHF. Nevertheless, more studies are needed and certain issues should be resolved, particularly the optimal hemoglobin level, before EPO can become part of the treatment of patients with CHF.

Iron and anemia in human biology: a review of mechanisms

The biology of iron in relation to anemia is best understood by a review of the iron cycle, since the majority of iron for erythropoiesis is provided by iron recovered from senescent erythrocytes. In iron-deficiency anemia, storage iron declines until iron delivery to the bone marrow is insufficient for erythropoiesis. This can be monitored with clinical indicators, beginning with low plasma ferritin, followed by decreased plasma iron and transferrin saturation, and culminating in red blood cells with low-Hb content. When adequate dietary iron is provided, these markers show return to normal, indicating a response to the dietary supplement. Anemia of inflammation (also known as anemia of chronic disease, or ACD) follows a different course, because in this form of anemia storage iron is often abundant but not available for erythropoiesis. The diagnosis of ACD is more difficult than the diagnosis of iron-deficiency anemia, and often the first identified symptom is the failure to show a response to a dietary iron supplement. Confirmation of ACD is best obtained from elevated markers of inflammation. The treatment of ACD, which typically employs erythropoietin (EPO) supplements and intravenous iron (i.v.-iron), is empirical and often falls shorts of therapeutic goals. Dialysis patients show a complex pattern of anemia, which results from inadequate EPO production by the kidney, inflammation, changes in nutrition, and blood losses during treatment. EPO and i.v.-iron are the mainstays of treatment. Patients with heart failure can be anemic, with incidence as high as 50%. The causes are multifactorial; inflammation now appears to be the primary cause of this form of anemia, with contributions from increased plasma volume, effects of drug therapy, and other complications of heart disease. Discerning the mechanisms of anemia for the heart failure patient may aid rational therapy in each case.

Heart failure and anemia: mechanisms and pathophysiology

Anemia is a common comorbidity in patients with heart failure and affects up to 50% of patients, depending on the definition of anemia used and on the population studied. Presence of anemia and lower hemoglobin (Hgb) concentrations are powerful independent predictors of adverse outcomes in heart failure. Even small reductions in Hgb are associated with worse outcomes. Correction of anemia may be useful in improving heart failure outcomes. However, the causes of anemia in heart failure are not entirely clear. Specific causes of anemia such as hematinic abnormalities are seen only in a minority of subjects. Renal dysfunction and neurohormonal and proinflammatory cytokine activation appear to contribute to anemia of chronic disease in the majority of the patients, resulting in inappropriate erythropoietin production and defective iron utilization. Under normal conditions, reduced tissue oxygenation due to chronic anemia results in non-hemodynamic and hemodynamic compensatory responses to enhance oxygen carrying capacity. Erythropoiesis is the predominant non-hemodynamic response to hypoxia, but because erythropoiesis is defective in heart failure, hemodynamic mechanisms predominate. Hemodynamic responses are complex and involve a vasodilation-mediated high-output state with neurohormonal activation. The high-output state initially helps to increase oxygen transport. However, the hemodynamic and neurohormonal alterations could potentially have deleterious long-term consequences and could contribute to anemia's role as an independent risk factor for adverse outcomes.

Heart disease and erythropoietin

An additional target for reducing infarct size, namely, attenuation of apoptosis, has recently emerged. Erythropoietin (Epo) exhibits properties that may attenuate this process and enhance neovascularization, thereby preserving jeopardized myocardium. Potentially adverse effects of Epo, including hypertension, thrombosis and possible exacerbation of occult neoplasms can likely be averted with analogues such as carbamylated and asialo Epo, which are devoid of erythropoietic effects, yet retain tissue-protective characteristics. With a single, but adequate dose of Epo administered early after the onset of acute myocardial infarction, coupled with therapy to induce reperfusion, tissue protection conferred by Epo and its analogues may facilitate the preservation of myocardium subjected to ischemic insults, thereby improving prognosis.