High serum erythropoietin levels are normalized during treatment of congestive heart failure with enalapril

Iron Dyshomeostasis and Mitochondrial Function in the Failing Heart: A Review of the Literature

Cardiac contraction and relaxation require a substantial amount of energy provided by the mitochondria. The failing heart is adenosine triphosphate (ATP)- and creatine-depleted. Studies have found iron is involved in almost every aspect of mitochondrial function, and previous studies have shown myocardial iron deficiency in heart failure (HF). Many clinicians advocated intravenous iron repletion for HF patients meeting the conventional criteria for systemic iron deficiency. While clinical trials showed improved quality of life, iron repletion failed to significantly impact survival or significant cardiovascular adverse events. There is evidence that in HF, labile iron is trapped inside the mitochondria causing oxidative stress and lipid peroxidation. There is also compelling preclinical evidence demonstrating the detrimental effects of both iron overload and depletion on cardiomyocyte function. We reviewed the mechanisms governing myocardial and mitochondrial iron content. Mitochondrial dynamics (i.e., fusion, fission, mitophagy) and the role of iron were also investigated. Ferroptosis, as an important regulated cell death mechanism involved in cardiomyocyte loss, was reviewed along with agents used to manipulate it. The membrane stability and iron content of mitochondria can be altered by many agents. Some studies are showing promising improvement in the cardiomyocyte function after iron chelation by deferiprone; however, whether the in vitro and in vivo findings will be reflected on on clinical grounds is still unclear. Finally, we briefly reviewed the clinical trials on intravenous iron repletion. There is a need for more well-simulated animal studies to shed light on the safety and efficacy of chelation agents and pave the road for clinical studies.

Inhibition of the renin-angiotensin system in the cardiorenal syndrome with anaemia: a double-edged sword

: The term 'cardiorenal syndrome' (CRS) was introduced to describe problems related to the simultaneous existence of heart and renal insufficiency. The prevalence of anaemia in CRS is high and increases the risk of hospitalizations and death. Renin-angiotensin system (RAS) inhibition is the cornerstone therapy in cardiovascular and renal medicine. As angiotensin II regulates both glomerular filtration rate (GFR) and erythropoiesis, RAS inhibition can further deteriorate renal function and lower hematocrit or cause anaemia in patients with heart failure. The aim of this review is to explore the relationship among CRS, anemia and administration of angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) and summarize the evidence suggesting that RAS inhibition may be considered an iatrogenic cause of deterioration of CRS with anemia. It should be emphasized however, that RAS inhibition reduces mortality in both groups with and without worsening of renal function, and therefore, no patient with CRS should be denied an ACEi or ARB trial without careful evaluation.

A randomized clinical trial to determine the effect of angiotensin inhibitors reduction on creatinine clearance and haemoglobin in heart failure patients with chronic kidney disease and anaemia

BACKGROUND

Chronic kidney disease is a common comorbidity in elderly patients with heart failure. Evidence supports the use of angiotensin inhibitors for patients with heart failure. However, there is little evidence with which to assess the risk and benefits of this treatment in elderly patients with renal dysfunction.

OBJECTIVE

To determine the efficacy and safety of angiotensin inhibitor reduction in patients with heart failure, chronic kidney disease and anaemia.

STUDY DESIGN

Open randomized controlled clinical trial.

SETTING

Complexo Hospitalario Universitario A Coruña (Spain).

PATIENTS

Patients ≥ 50 years old, with heart failure, haemoglobin (Hb) < 12 mg/dl and creatinine clearance <60 ml/min/1.73 m(2) admitted to hospital, in treatment with angiotensin inhibitors. Informed consent and Ethical Review Board approval were obtained.

INTERVENTION

A 50% reduction of angiotensin inhibitor dose of the basal treatment on admission (n = 30) in the intervention group. Control group (n = 16) with the standard basal dose.

MAIN OUTCOME MEASURE

Primary outcome was difference in Hb (gr/dl), creatinine clearance (ml/min/1.73 m(2) ) and protein C (mg/dl) between admission and 1-3 months after discharge. Secondary outcome was survival at 6-12 months after discharge.

RESULTS

Patients in the intervention group experienced an improvement in Hb (10.62-11.47 g/dl), creatinine clearance (32.5 ml/min/1.73 m(2) to 42.9 ml/min/1.73 m(2) ), and a decrease in creatinine levels (1.98-1.68 mg/dl) and protein C (3.23 mg/dl to 1.37 mg/dl). There were no significant differences in these variables in the control group. Survival at 6 and 12 months in the intervention and control group was 86.7% vs. 75% and 69.3% vs. 50%, respectively.

CONCLUSION

The reduction of the dose of angiotensin inhibitors in the intervention group resulted in an improvement in anaemia and kidney function, decreased protein C and an increased survival rate.

TRIAL REGISTRATION

EudraCT: 2008-008480-10.

The sex difference in haemoglobin levels in adults - mechanisms, causes, and consequences

Men and women have different mean haemoglobin levels in health in venous blood - women have mean levels approximately 12% lower than men. A similar sex-related difference in haemoglobin levels in adult animals is found in many species of mammals, birds and reptiles, indicating that it is an important physiological phenomenon. It is probably a direct effect of sex hormones, both oestrogen and androgens, on erythropoiesis. However, since there is no difference in erythropoietin levels between the sexes, this effect most likely takes place in the kidney, rather than in the bone marrow. Oestrogens dilate and androgens constrict the renal microvasculature: dilation and vasoconstriction in vessels below 300 μm in diameter respectively increase and decrease the haematocrit in blood in arterioles, capillaries and venules, altering the oxygen delivery per unit red cell mass, and providing a mechanism for varying the red cell mass without compensatory changes in erythropoiesis.

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.

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.

Prevalence of anemia in heart failure and its effects on prognosis

Anemia is common in heart failure patients but its prevalence varies widely according to various sources. There is no agreement regarding the definition of anemia to be used and several risk factors have been found to be associated with higher prevalence of anemia in heart failure patients. The prevalence of anemia depends on its definition and the clinical characteristics of the patients included in the studies. Anemia is associated with adverse prognosis in the general population, in patients with end-stage renal disease, chronic diseases, coronary artery disease and also in patients with heart failure; however, despite all the information available, the issue of whether anemia is an independent predictor of mortality and the nature of the risk between anemia and mortality in heart failure patients are not yet fully understood.

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.

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.

Direct cardiac actions of erythropoietin (EPO): effects on cardiac contractility, BNP secretion and ischaemia/reperfusion injury

EPO (erythropoietin) has recently been shown to have protective actions upon the myocardium; however, the direct effects of EPO upon cardiac contractile and secretory functions are unknown and the signalling mechanisms are not well defined. In the present study, we provide the first evidence of direct cardiac contractile actions of EPO. In isolated perfused Sprague-Dawley rat hearts, a 30 min infusion of EPO significantly increased contractility in a dose-dependent fashion (maximal change 18+/-2% with 1 unit/ml EPO; P<0.005 compared with vehicle). Perfusate ET-1 (endothelin-1) increased transiently during EPO infusion, and the ET(A/)ET(B) antagonist bosentan abolished the inotropic response to EPO. BNP (B-type natriuretic peptide) secretion (28+/-8%; P<0.05) and nuclear transcription factor GATA-4 DNA-binding activity (51%; P<0.05) were both significantly increased by EPO and blocked by bosentan. In a model of global ischaemic injury, delivery of 1 unit/ml EPO during reperfusion significantly attenuated creatine kinase release (28+/-12%; P<0.05) and significantly improved contractile recovery (P<0.001), independent of ET(A) blockade. Apoptotic indices [assessed by TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling)/cleaved caspase-3-positive cells] were significantly decreased (P<0.01) by 1 unit/ml EPO during reperfusion alone, coincident with significantly increased phosphorylation of myocardial JAK2 (Janus kinase 2) and STAT3 (signal transducer and activator of transcription 3). Thus EPO directly enhances cardiac contractility and BNP secretion and alleviates ischemia/reperfusion injury via ET-1-dependent and -independent mechanisms respectively.

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.

Antihypertensive Medications and Anemia

Antihypertensive medication use can be associated with a reduction in hemoglobin concentration. The magnitude of such a change is generally small, but in certain instances it can be extreme enough to produce a clinically significant degree of anemia. The mechanistic basis for antihypertensive medication-related changes in hemoglobin concentration include hemodilution, hemolytic anemia, and suppression of red blood cell production, as this occurs most commonly with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers. A reduction in hemoglobin concentration in a patient who is receiving treatment for hypertension and does not have an obvious source of blood loss should account for potential antihypertensive therapy involvement.

IGF-1 is an independent risk factor for anemia in diabetic pre-dialysis patients

BACKGROUND

We investigated whether the presence of diabetes mellitus (DM) was related to the degree of the anemia in predialytic patients with renal failure and what was the most relevant factor for anemia in patients with chronic kidney disease (CKD) from DM (DM-CKD).

METHODS

Seventy seven patients (47 predialytic patients with long-term type 2 DM (DM-CKD) and 30 predialytic patients whose disease was due to other causes (non DM-CKD)) were enrolled in this study. The blood hemoglobin (Hb) and hematocrit, and the creatinine, ferritin, vitamin B12, folate, iron, LDH, albumin, hs-CRP, intact-PTH, erythropoietin, leptin and Insulin-like growth factor I (IGF-1) levels were measured using standard methods. The estimated GFR was calculated using the abbreviated MDRD equation.

RESULTS

The two groups did not significantly differ as to age, gender, the serum creatinine level and the inflammatory status. The Hb level was significantly lower in the DM-CKD patients than that in the non DM-CKD patients (8.5+/-1.7 g/dL vs 9.6+/-1.6 g/dL, respectively, p=0.01). The Hb level was significantly lower in the DM-CKD patients who were being treated with ACE inhibitors (the DM-ACE patients) than that in the non DM-CKD patients who were being treated with ACE inhibitors (the non DM-ACE patients) (8.5+/-1.5 g/dL vs 10.8+/-1.6 g/dL, respectively, p=0.001). Multiple regression analysis indicated that serum IGF-1 concentration was independently associated with the Hb level (beta=0.425, p=0.02) in the DM-CKD patients.

CONCLUSIONS

The Hb concentration was significantly lower in the DM-CKD patients than that in the non DM-CKD patients. It was independently associated with the serum IGF-1 concentration in the DM-CKD patients.

Hemoglobin and N-terminal pro-brain natriuretic peptide: Independent and synergistic predictors of mortality in patients with acute heart failure

BACKGROUND

Hemoglobin and amino-terminal pro-brain natriuretic peptide (NT-proBNP) are both independent predictors of mortality in patients with chronic HF. Their combined predictive power for mortality in the setting of acute HF is uncertain.

METHODS

In an international prospective cohort design, we evaluated the relationships between hemoglobin, NT-proBNP, and 60-day mortality in 690 patients with acute HF.

RESULTS

The median hemoglobin for the entire cohort was 13.0 g/dL (interquartile range 11.6-14.3). The WHO criterion for anemia was met by 44% (n=305). The 60-day mortality rate for anemic patients was 16.4% vs. 8.8% in non-anemic patients (p<0.001). Anemia was an independent predictor of short-term mortality (OR=1.72, 95% CI=1.05-2.80, p=0.03), as was a NT-proBNP concentration >5180 pg/mL (OR=2.32, 95% CI=1.36-3.94 p=0.002). Consideration of four risk groups: not anemic/low NT-proBNP (reference group, n=220), anemic/low NT-proBNP (n=152), not anemic/high NT-proBNP (n=165), and anemic/high NT-proBNP (n=153) revealed respective 60-day mortality rates of 5.0% (referent), 9.2% (OR=1.93, 95% CI=0.85-4.36; p=0.12), 13.9% (OR=3.07, 95% CI=1.45-6.50, p=0.003), and 23.5% (OR=5.84, 95% CI=2.87-11.89, p<0.001).

CONCLUSIONS

Anemia was common in this cohort of subjects with acute HF and was related to adverse short-term outcome. Integrated use of hemoglobin and NT-proBNP measurements provides powerful additive information and is superior to the use of either in isolation.

HEMATOLOGY: ISSUES IN THE DIALYSIS PATIENT: Erythropoietin Resistance in the Treatment of the Anemia of Chronic Renal Failure

Resistance to erythropoietin therapy is a common complication of the modern management of anemia in chronic kidney disease. Iron deficiency, deficiency of other nutrients, toxins, infections, and inadequate dialysis account for the vast majority of episodes of such resistance.

Cardiovascular Effects of Erythropoietin

We did a PubMed and Cochrane Database System review of different studies on the diverse effects of erythropoietin (EPO), focusing mainly on the cardiovascular system. The direct erythropoietic action of EPO is well studied and widely used. Published studies report dramatic improvement in the course of heart failure with EPO treatment. New controlled clinical trials on large and diverse groups of patients are warranted. Antiapoptotic effects of EPO are newly discovered, opening new horizons in both clinical investigation and therapy. The salvage of cardiomyocytes in acute coronary syndromes, limiting the size of myocardial infarction and improving functional recovery, is only one of multiple potential applications of this effect. Derivatives of EPO with selective antiapoptotic properties seem to hold the best prospects for future studies. Heart failure and ischemic heart disease are potential areas where adding EPO to the conventional treatment may be beneficial.

Clinical effects of endothelin receptor antagonism with bosentan in patients with severe chronic heart failure: results of a pilot study

BACKGROUND

Endothelin receptor antagonism produces favorable short-term hemodynamic effects in heart failure, but the clinical effects of longer term therapy have not been evaluated.

METHODS AND RESULTS

Three hundred and seventy patients with symptoms of heart failure at rest or on minimal exertion and a left ventricular ejection fraction <35% were randomly assigned (double-blind) to placebo (n = 126) or the endothelin receptor antagonist bosentan, titrated slowly (n = 121) or rapidly (n = 123) to a target dose of 500 mg twice daily. Treatment with the study drug was to be maintained for 26 weeks, whereas background medications for heart failure were kept constant. Safety concerns led to early termination of the trial when only 174 patients had had an opportunity to complete 26 weeks of therapy. Bosentan exerted no apparent benefit when all randomized patients were analyzed (P = .709). However, in the first 174 patients who were recruited at least 26 weeks before study termination and who could therefore be followed for the planned duration of the trial, patients in the bosentan groups were more likely to be improved (26% versus 19%) and were less likely to be worse (28% versus 43%), P = .045. When compared with placebo-treated patients, bosentan-treated patients had a increased risk of heart failure during the first month of treatment but a decreased risk of heart failure during the fourth, fifth, and sixth months of therapy. The major noncardiac adverse effects of bosentan included an increase in hepatic transaminases (in 15.6% of patients) and a decrease in hemoglobin (of about 1 g/L).

CONCLUSION

Although bosentan exerted no favorable effects in the overall study, our findings suggest that the clinical responses to endothelin antagonism with bosentan in patients with severe chronic heart failure may be dependent on the duration of treatment.

Mechanisms and Treatment of Anemia in Chronic Heart Failure

Anemia is highly prevalent in patients with chronic heart failure (HF) and is associated with poor clinical outcomes. Multiple mechanisms contribute to anemia in chronic HF, and subnormal compensatory rise in endogenous erythropoietin levels in response to anemia is one contributory factor. Randomized trials with recombinant human erythropoietin therapy in anemic patients with chronic kidney disease and concomitant heart disease have demonstrated a reduction in left ventricular hypertrophy but variable effects on clinical outcome. Preliminary clinical trials in anemic patients with chronic HF demonstrate that erythropoietin therapy is well tolerated and associated with short-term clinical improvement. The optimum target hemoglobin, erythropoietic agent, and dosing regimen, and the role of iron supplementation in patients with chronic HF, are not known. Additional studies are needed to determine the safety and efficacy of long-term erythropoietic therapy in chronic HF patients.

Anemia as a risk factor and therapeutic target in heart failure

Anemia has recently been recognized as an important comorbid condition and potentially novel therapeutic target in patients with heart failure (HF). Anemia is common in HF patients, with a prevalence ranging from 4% to 55% depending on the population studied. Multiple potential mechanisms of interaction exist between anemia and the clinical syndrome of HF, including hemodilution, inflammatory activation, renal insufficiency, and malnutrition. A growing body of literature from observational databases and clinical trials suggests that anemia is an independent risk factor for adverse outcomes in patients with HF. Although preliminary data suggest that treatment of anemia may result in significant symptomatic improvement in HF, aggressive treatment of anemia may also be associated with increased risk of hypertension or thrombosis. Multiple ongoing studies will provide definitive data on the balance of risks and benefits of anemia treatment in chronic HF.

Anemia in chronic heart failure: pathogenetic mechanisms

Anemia can be the cause of heart failure, but also its consequence. The pathogenesis of anemia in chronic heart failure (CHF) has yet to be fully elucidated, but is likely to be complex. Epidemiologic studies suggest that kidney dysfunction (by reducing the erythropoietic response to anemia), inflammation (by inducing erythropoietin resistance), decreased body mass index, old age, female gender, and poor clinical status may be important factors in the development of anemia in CHF. Intestinal malabsorption, chronic aspirin use, and proteinuria predisposes to iron deficiency. Proinflammatory cytokines are likely to play a significant role in anemia in CHF by generating the "anemia of chronic illness" that is a hallmark of inflammatory conditions. Few studies have investigated the mechanisms of anemia in CHF. There is a need for such studies.

Are hematinic deficiencies the cause of anemia in chronic heart failure?

BACKGROUND

Anemia in chronic heart failure (CHF) is common, varying in prevalence between 14.4% and 55%, and is more frequent in patients with more severe heart failure. Patients with CHF who have anemia have a poorer quality of life, higher hospital admission rates, and reduced exercise tolerance. We explored the relation between hematinic levels and hemoglobin (Hb) levels and exercise tolerance in a group of patients with CHF.

METHODS

We analyzed data from 173 patients with left ventricular systolic dysfunction (LVSD), 123 patients with symptoms of heart failure, but preserved left ventricular (LV) systolic function ("diastolic dysfunction"), and 58 control subjects of similar age. Each underwent echocardiography, a 6-minute walk test, and blood tests for renal function and Hb and hematinic levels (vitamin B12, iron, and folate). We classified patients as having no anemia (Hb level >12.5 g/dL), mild anemia (Hb level from 11.5-12.5 g/dL), or moderate anemia (Hb level <11.5 g/dL).

RESULTS

Of patients with LVSD, 16% had moderate anemia and 19% had mild anemia. Of patients with preserved LV function, 16% had moderate anemia and 17% had mild anemia. Four control subjects had a Hb level <12.5 g/dL. Of all patients, 6% were vitamin B12 deficient, 13% were iron deficient, and 8% were folate deficient. There was no difference between patients with LVSD and the diastolic dysfunction group. In patients with LVSDS, the average Hb level was lower in New York Heart Association class III than classes II and I. The distance walked in 6 minutes correlated with Hb level in both groups of patients with CHF (r = 0.29; P <.0001). Patients with anemia achieved a lower pVO2 (15.0 [2.3] vs 19.5 [4.4], P <.05). Peak oxygen consumption correlated with Hb level (r = 0.21, P <.05) in the patients, but not in the control subjects. In patients with anemia, the mean creatinine level was higher than in patients with a Hb level >12.5 g/dL, but there was no clear relationship with simple regression. Hematocrit level and mean corpuscular volume were not different in the patients with diastolic dysfunction, patients with LV dysfunction, or the control subjects. Hematocrit levels were not influenced by diuretic dose. Patients with anemia were not more likely to be hematinic deficient than patients without anemia.

CONCLUSIONS

Patients with symptoms and signs of CHF have a high prevalence of anemia (34%) whether they have LV dysfunction or diastolic dysfunction, but few patients have hematinic deficiency. Hemoglobin levels correlate with subjective and objective measures of severity and renal function.

Renal oxygenation defects in the spontaneously hypertensive rat: role of AT1 receptors

BACKGROUND

The spontaneously hypertensive rat (SHR) has oxidative stress and enhanced O2 usage (Q(O2)) relative to tubular sodium transport (TNa). Angiotensin II (Ang II) acting on Type I receptors (AT1-R) causes renal oxidative stress and functional nitric oxide (NO) deficiency that could enhance O2 usage. Therefore, we investigated the hypothesis that AT1-Rs mediate the inefficient renal oxygenation in the SHR.

METHODS

Groups of SHR and WKY received vehicle (Veh), candesartan (Cand) or hydralazine + hydrochlorothiazide + reserpine (HHR) for two weeks.

RESULTS

Compared to WKY + Veh, the elevated BP of SHR + Veh (153 +/- 3 vs 115 +/- 3 mm Hg; P < 0.001) was normalized by Cand (117 +/- 4) or HHR (113 +/- 5 mm Hg). The reduced renal blood flow of SHR + Veh (2.4 +/- 0.3 vs. 4.1 +/- 0.3 mL. min-1. 100 g-1) was increased (P < 0.05) by Cand (3.6 +/- 0.3) and HHR (3.2 +/- 0.2). Compared to WKY + Veh, SHR + Veh had a 50% reduction in TNa: (16.9 +/- 2.0 vs. 7.8 +/- 0.9 micromol: micromol-1, P < 0.01) that was unchanged by HHR (8.6 +/- 1.1), but was increased by Cand (13.2 +/- 1.4; P < 0.01). The pO2 of outer cortex was lower in SHR + Veh than WKY + Veh (31 +/- 3 vs. 41 +/- 2 mm Hg; P < 0.05) and it was not changed significantly by HHR (37 +/- 2) but was normalized by Cand (44 +/- 3 mm Hg; P < 0.01). The pO2 in the deep cortex also was lower in SHR + Veh than WKY + Veh (18 +/- 3 vs. 30 +/- 3 mm Hg; P < 0.005) and was not changed significantly by HHR (19 +/- 2), but was increased by Cand (25 +/- 3 mm Hg; P < 0.05).

CONCLUSIONS

The reduced pO2 in outer and inner cortex, and inefficient utilization of O2 for Na+ transport in the SHR kidney can be ascribed to the effects of AT1-R, largely independent of blood pressure.

Effects of losartan or enalapril on hemoglobin, circulating erythropoietin, and insulin-like growth factor-1 in patients with and without posttransplant erythrocytosis

Both angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists reduce hemoglobin (Hb) levels in patients with posttransplantation erythrocytosis (PTE). However, their effects in transplant recipients without PTE are not certain, and the mechanism by which they reduce Hb levels in patients with PTE remains unclear. This study evaluated the effects of losartan and enalapril on Hb levels in relation to serum erythropoietin (EPO) and insulin-like growth factor-1 (IGF-1) levels in 8 patients with PTE and 10 patients without PTE. All 18 patients were treated sequentially with 24 weeks of losartan therapy, followed by 24 weeks of enalapril therapy; the two treatment phases were separated by a washout period. Patients with PTE showed significantly greater baseline Hb and IGF-1 concentrations compared with patients without PTE before both losartan and enalapril treatments. Baseline serum EPO levels were similar for patients with and without PTE. Baseline Hb level correlated significantly with IGF-1 level (r = 0.517; P = 0.002), but not with EPO level. Treatment with enalapril, 5 mg, reduced Hb levels more markedly than treatment with losartan, 50 mg, in patients with PTE. In patients without PTE, enalapril, 5 mg, mildly reduced Hb levels, whereas losartan, 50 mg, had no significant Hb-lowering effect. The reduction in Hb levels with enalapril therapy in patients with PTE was associated with a significant reduction in circulating IGF-1 levels, but not EPO levels, whereas losartan reduced Hb levels with no significant change in circulating IGF-1 and EPO levels. In patients without PTE, no significant change was noted in serum EPO and IGF-1 levels with either treatment. The differential Hb-lowering effect with losartan and enalapril treatment in patients with and without PTE suggests that the pathogenesis for PTE is complex and heterogeneous. Different erythropoietic mechanisms may be involved in patients with and without PTE. Further large-scale study is needed to determine the exact interaction between the renin-angiotensin system and regulation of IGF-1 and EPO synthesis and define the exact mechanism by which losartan and enalapril reduce Hb levels.

Angiotensin II infusion increases plasma erythropoietin levels via an angiotensin II type 1 receptor-dependent pathway

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACEIs) have been shown to lower hematocrit and erythropoietin (EPO), but a direct link between angiotensin II (Ang II) and EPO in humans has not been shown.

METHODS

Placebo or Ang II was infused for six hours in nine healthy male volunteers with and without blockade of the Ang II subtype 1 receptor (AT1R). EPO concentrations were measured 3, 6, 12, and 24 hours after the start of the infusion.

RESULTS

Ang II raised the mean arterial pressure by about 20 mm Hg. Consistent with the known diurnal variation, EPO levels rose significantly (P < or = 0.02) during the day in all groups. During Ang II infusion, EPO levels rose to significantly higher levels after 6 and 12 hours compared with placebo [9.9 +/- 3.5 vs. 7.2 +/- 3.1 mU/mL (3 h, P = NS); 16.9 +/- 4.5 vs. 8.8 +/- 3.7 mU/mL (6 h, P = 0.01); 17.0 +/- 8.6 vs. 11.1 +/- 4.7 mU/mL (12 h, P = 0.01)] and returned to baseline after 24 hours (7.9 +/- 3.8 vs. 10.6 +/- 8.6 mU/mL, P = NS). With AT1R blockade, blood pressure remained normal during Ang II infusion, and EPO levels were never significantly different from placebo [6.8 +/- 4.8, 10.5 +/- 5.6, 13.1 +/- 9.0, and 12.4 +/- 10.1 mU/mL at 3, 6, 12, and 24 h after infusion, respectively, P = NS].

CONCLUSIONS

Ang II increases EPO levels in humans. This increase requires the participation of AT1R.

Efficacy and safety of angiotensin II receptor blockers in elderly patients with mild to moderate hypertension

The role of the renin-angiotensin-aldosterone system in the pathogenesis of hypertensive disease has long been recognized, and the interruption of this cascade with angiotensin-converting enzyme-I has been beneficial in the management of hypertension. Recently, a new class of drugs, the angiotensin receptor blockers, emerged, enlarging the antihypertensive armamentarium. Since elderly patients are more prone to adverse drug reactions, in this paper we review several trials, most of which were of short duration, on the efficacy and safety of angiotensin receptor blockers in the geriatric population with mild to moderate hypertension. These studies established that the drugs are well-tolerated, safe, and in most instances as efficacious as other classes of antihypertensive medications. Combination therapy with angiotensin receptor blockers and hydrochlorothiazide was additive, without any significant effect on the safety profile.

Serum erythropoietin in heart failure patients treated with ACE-inhibitors or AT(1) antagonists

BACKGROUND

Erythropoietin (Epo), a growth factor produced by the kidney, is important in heart failure patients to promote oxygen delivery to tissues. Seventy-two chronic heart failure (CHF) patients at our outpatient clinic were subjected to morning serum Epo-level measurements and classified according to NYHA criteria.

RESULTS

Forty-eight patients of classes III and IV had a significantly elevated serum Epo-level of 42.9+/-40.3 mIU/ml (mean+/-1 S.D.) when compared to the mean level of 24 patients of classes I and II who had a normal range mean value of 13.4+/-6.2 mIU/ml (P<0.05). Patients on angiotensin-converting enzyme (ACE) inhibitors showed a trend towards lower serum Epo-levels compared to patients treated with angiotensin-II type-1 receptor antagonists (AT(1) antagonists) (levels: 33.3+/-35.6 mIU/ml and 43.6+/-38.1 mIU/ml). This trend did not, however, reach statistical significance (P=0.36).

CONCLUSION

We suggest that a desirable Epo increase in class III and IV CHF patients could be achieved by either recombinant human Epo administration or, possibly, by appropriate selection of the concomitant medical therapy. A large prospective study shall investigate the possible advantage of AT(1) antagonists over ACE-inhibitors with regard to Epo effect.

Pharmacotherapy in congestive heart failure: ACE inhibitors and anemia in congestive heart failure

The use of angiotensin-converting enzyme inhibitors can be accompanied by a number of adverse events, including cough, angioedema, and hyperkalemia, as well as a peculiar form of functional renal insufficiency. Other, less obvious side effects accompany ACE inhibitor use, such as a reduction in red blood cell production. This feature of ACE inhibitor use may be employed to good effect, as in the management of post-transplant erythrocytosis. Alternatively, the suppressive effect of ACE inhibitors on red blood cell production may intensify the anemia of chronic renal failure and/or congestive heart failure. The untreated congestive heart failure patient typically has an increased red blood cell mass as a consequence of increased erythropoietin levels, with the latter governed by congestive heart failure-related renal hypoxia. This is not expressed as an increase in hemoglobin concentration because of the increase in plasma volume that marks advanced congestive heart failure. ACE inhibitor therapy can be expected to both reduce plasma volume and decrease red blood cell production. As a result, the hemoglobin concentration changes very little in the ACE inhibitor-treated congestive heart failure patient and usually falls in the low normal range. Recently, erythropoietin has been employed to good effect in congestive heart failure patients with borderline anemia. (c)2000 by CHF, Inc.

ACE inhibitors do not induce recombinant human erythropoietin resistance in hemodialysis patients

Angiotensin-converting enzyme (ACE) inhibitors may exacerbate anemia in patients with chronic renal failure, as well as in dialysis patients. To better answer this question, a prospective, crossover study was conducted to evaluate the effect of ACE inhibitors on recombinant human erythropoietin (rHuEPO) requirements in hemodialysis patients. Patients administered an ACE inhibitor when entering the study remained on this drug for the initial 4 months and were then switched to another antihypertensive agent for 4 more months. Patients not initially administered an ACE inhibitor were switched to lisinopril at 4 months. rHuEPO doses were adjusted using a sliding scale based on weekly laboratory hematocrit values. The inclusion criteria were met by 51 patients undergoing dialysis. Demographics were as follows: 61% were women, 64% were black, 46% had diabetes, average age was 53.2 +/- 13.3 years, and time on hemodialysis was 38.0 +/- 44.5 months. Thirty-three patients completed the study. Hematocrit averaged 32.7% +/- 1.9% while on ACE inhibitor therapy and 33.1% +/- 2.1% off ACE inhibitor therapy (P = 0.217). There was no difference in rHuEPO dose per treatment during each period (3,500 +/- 1,549 U on ACE inhibitor therapy versus 3,312 +/- 1,492 U off ACE inhibitor therapy; P = 0.300). No significant differences were found in degree of blood pressure control or various clinical and laboratory parameters that might be associated with rHuEPO resistance between the two periods. Similarly, no differences were found in hospitalization days, duration of infections, or transfusion requirements. These findings suggest that ACE inhibitors do not contribute to rHuEPO resistance in hemodialysis patients.

Advanced glycosylation end products (AGEs), insulin-like growth factor-1 (IGF-1) and IGF-binding protein-3 (IGFBP-3) in patients with type 2 diabetes mellitus

BACKGROUND

Advanced glycosylation end product (AGE) formation is a major mechanism for the development of complications in diabetes, and the possible roles of insulin-like growth factor 1 (IGF-1) and IGF binding protein 3 (IGFBP-3) are not clearly established.

METHODS

We examined the associations of AGEs, free IGF-I and IGFBP-3 in Type 2 diabetes mellitus (DM) patients under diverse conditions. In a cross-sectional design we studied 110 subjects (67 women and 43 men): non-diabetic controls in group 1, (n = 15) and diabetes patients as follows: group 2, without complications (n = 25); group 3, with chronic complications (n = 25); group 4, with acute or chronic infections (n = 24); group 5, hospitalized for reasons unrelated to diabetes (n = 9); group 6, with end-stage renal disease (ESRD) (n = 12). AGEs were determined by a spectrofluorometric method (HPLC). Insulin and IGFBP-3 were measured by RIA and free IGF-1 with an IRMA method.

RESULTS

AGEs were 13-fold higher in patients with ESRD (p<0.001), and lower in healthy individuals. Free IGF-1 was lower in the patients with complications (p = 0.017), with infections (p = 0.006) and hospitalized (p = 0.04). IGFBP-3 was higher in hospitalized patients (p=0.017). AGEs were associated with free IGF-1 (r = 0.41, p = 0.04) in the group with complications, and with HbA(1c) (r = -0.90, p = 0.002) in hospitalized patients. In the total group, free IGF-1 (r = -0.25, p = 0.008), and IGFBP-3 (r = -0.22, p = 0.021) were associated with HbA(1c).

CONCLUSION

We concluded that AGEs were markedly increased in diabetic patients with ESRD, IGF-1 was decreased in patients with infections and hospitalized, and was negatively associated with HbA(1c). IGFBP-3 was increased in hospitalized patients, with higher levels in patients with long bone fractures. A complex interaction of humoral factors may participate in the acceleration of complications of diabetes.

Candesartan cilexetil: an angiotensin II receptor blocker

OBJECTIVE

To summarize and critique the medical literature on candesartan cilexetil, an angiotensin II receptor blocker (ARB).

DATA SOURCES

MEDLINE searches (January 1966-January 1999) and manufacturer prescribing literature were used to identify articles on candesartan cilexetil. Bibliographies were also reviewed for germane articles.

STUDY SELECTION

Study and review articles describing the chemistry, human pharmacology, pharmacodynamics, pharmacokinetics, placebo-controlled trials, comparative trials, and clinical application of candesartan cilexetil based on the published literature and premarketing clinical trials were reviewed.

DATA EXTRACTION

All literature on the use of candesartan cilexetil for treating hypertension and congestive heart failure were included.

DATA SYNTHESIS

ARBs are a new class of drugs with increasing use in treating hypertension. Studies are ongoing to determine the role of these agents in preventing remodeling after myocardial infarction and in patients with congestive heart failure. Candesartan cilexetil is among the newest drugs in the class that includes losartan, irbesartan, and valsartan. Candesartan cilexetil has more than 1000 times more affinity for the angiotensin II, type AT1 receptor ARBs, and the binding affinity and competitive angiotensin II receptor antagonism is stronger than that of losartan. Clinical studies in patients with hypertension have demonstrated that candesartan cilexetil, in doses of 4-16 mg, is more effective in reducing sitting diastolic blood pressure than are placebo and losartan 50 mg. Candesartan cilexetil has demonstrated reductions in blood pressure comparable to those of enalapril, with the rate of adverse events greater in the enalapril group. Dosage adjustments are not necessary in elderly patients or in patients with mild hepatic or renal dysfunction. In diabetic patients, blood glucose, hemoglobinA1c, and serum lipids are not affected. The clinical studies demonstrated that the adverse effect profile of candesartan cilexetil was similar to that of placebo and there were no dose-dependent adverse effects.

CONCLUSIONS

Candesartan cilexetil provides an alternative antihypertensive therapy that is well tolerated and effective in reducing blood pressure in a wide range of patients. Due to its greater binding affinity to the angiotensin II receptor, candesartan cilexetil appears to have a longer antihypertensive effect than losartan. This may be advantageous in decreasing morbidity and mortality associated with hypertension, although further studies are required to validate this potential advantage.

Interference of angiotensin-converting enzyme inhibitors on erythropoiesis in kidney transplant recipients: role of growth factors and cytokines

BACKGROUND

Recent data indicate that factors other than erythropoietin (EPO), such as insulin-like growth factor 1 (IGF-1), can promote erythropoiesis in vitro and correct the anemia of chronic renal failure in vivo. IGF-1 is produced by the liver under growth hormone control, as well as by other sources, including the kidney. The erythropoietic role of growth factors and cytokines and their possible modulation by angiotensin-converting enzyme inhibitors (ACEI) has never been explored.

METHODS

This study evaluated the serum levels of EPO, IGF-1, interleukin (IL)-2, IL-3, and granulocyte macrophage-colony-stimulating factor in 40 kidney transplanted patients with or without posttransplant erythrocytosis (PTE) and in 10 living kidney donors. Then, the effect of ACEI therapy on the above pattern was examined in patients with PTE.

RESULTS

EPO and IGF-1 serum levels were significantly higher in patients with PTE than in patients without PTE and in living kidney donor subjects. ACEI therapy significantly reduced hematocrit (Hct) as well as circulating IGF-1 and EPO levels. Of note, the decrease in IGF-1 was prominent mainly in those patients whose EPO levels were not significantly modified by ACEI therapy. In all of the patients Hct levels displayed a direct relationship with circulating IGF-1 levels, but not with EPO concentration. Growth hormone did not significantly differ among the groups examined, whereas it steeply increased under ACEI. Finally, no significant difference in IL-2, IL-3, and granulocyte macrophage-colony-stimulating factor serum levels was detected.

CONCLUSIONS

IGF-1 seems to play a role in the ACEI-related decrease of Hct in patients with PTE, chiefly in patients without any modification of EPO serum levels.

Efficacy of enalapril after ineffective theophylline treatment on erythrocytosis after renal transplantation

Erythrocytosis represents a common complication in renal allograft recipients. Traditional therapies including phlebotomy and bilateral native nephrectomies are cumbersome for both the clinical personnel and the patient. Recently, pharmacological agents such as angiotensin converting enzyme inhibitor and theophylline have been proposed as effective therapies for post-transplant erythrocytosis (PTE). We have treated a PTE patient successfully with enalapril without any side effects and renal dysfunction after theophylline treatment showed no improvement in PTE. A decline in Ht levels was independent of the changes in Epo levels during enalapril treatment. Although the mechanism underlying the beneficial effect of enalapril remains undetermined, enalapril is recommended for the initial treatment of PTE.

Erythropoietin and base excess levels in patients with chronic pulmonary diseases

Factors which could influence serum erythropoietin (s-EPO) levels in patients with chronic pulmonary diseases were investigated, paying special attention to the role of changes in acid-base balance (PaCO2, HCO3- and base excess levels) in EPO production. Data from 30 patients with chronic pulmonary diseases (chronic pulmonary emphysema, chronic bronchitis and post-tuberculosis status) were obtained in the morning and were analyzed with a stepwise forward multiple regression analysis, evaluating the statistical significance of seven factors which may potentially influence s-EPO levels: arterial pH, PaCO2, PaO2, HCO3-, base excess (BE), SaO2 and hemoglobin (Hb). Significant simple correlations (P < 0.01) of log(s-EPO) were obtained with PaO2 (r = -0.66), PaCO2 (r = 0.59), HCO3- (r = 0.67), BE (r = 0.71) and SaO2 (r = -0.77). The stepwise forward multiple regression analysis revealed that significant correlate variables for the outcome variable of log(s-EPO) were SaO2 and BE, with r = 0.823 (P < 0.0001). In patients with chronic pulmonary diseases it was shown that SaO2 was a negative correlate and BE was a positive correlate of s-EPO levels. It was speculated that s-EPO levels in the morning reflected daytime hypoxemia (SaO2) and nocturnal desaturation evoked by hypopnea during sleep (indicated as BE) in these patients.

Erythropoietin in the control of red cell production

The understanding of the endocrine regulation of red cell production has been extended greatly since the erythropoietin gene was cloned and recombinant human erythropoietin has become available for experimental and clinical applications. Human erythropoietin is a 30 kDa glycoprotein. It is composed of 165 amino acids and 4 carbohydrate side chains. Studies in rodents have shown that blood-borne erythropoietin originates from peritubular cells, possibly fibroblasts, in the renal cortex and from parenchymal cells in the liver. In addition, erythropoietin mRNA has been demonstrated in spleen, lung and brain. Tissue hypoxia is the main stimulus for erythropoietin synthesis. Erythropoietin gene expression is controlled by DNA-binding proteins, primarily by hypoxia-inducible factor 1. Erythropoietin maintains red cell production by inhibiting apoptosis of erythrocytic progenitors, and by stimulating their proliferation and differentiation into normoblasts. The functional human erythropoietin receptor, a 484-amino acid glycoprotein, is member of the class I cytokine receptor superfamily. Lack of erythropoietin results in anaemia. Recombinant human erythropoietin is efficient for treatment of the anaemia of chronic renal failure. In addition, the drug is increasingly administrated to persons suffering from anaemia of chronic diseases and to surgical patients, thus abolishing the need for homologous red cell transfusion.

Mechanism of angiotensin converting enzyme inhibitor-related anemia in renal transplant recipients

To delineate the pathogenesis of the reduction in hemoglobin occurring in renal transplant patients treated with angiotensin converting enzyme inhibitors (ACEI) and azathioprine (AZA) a controlled, prospective trial of ACEI withdrawal was conducted. The ACEI was replaced by nifedipine or clonidine in 15 kidney transplant patients immunosuppressed with AZA and prednisone (enalapril in 14 and captopril in 1). Before and during 10 to 12 weeks after withdrawal of the ACEI, AZA metabolites, renal function parameters and hematological parameters including erythropoietin and reticulocytes were evaluated. Enalaprilat levels were measured and compared with 15 similar patients matched for transplant function and enalapril dosage immunosuppressed with cyclosporine and prednisone. AZA metabolites did not differ significantly in the presence or absence of the ACEI. Enalaprilat levels also showed no significant difference between the two patient groups treated with AZA or cyclosporine. Hematocrit and hemoglobin increased significantly from 37.5 +/- 6.4 to 39.7 +/- 3.6% (mean +/- SD, P = 0.02) and 12.8 +/- 2.2 to 13.5 +/- 1.2 g/dl, P = 0.04, respectively, 10 to 12 weeks after ACEI treatment had been discontinued. Simultaneously numbers of reticulocytes and erythropoietin concentrations rose significantly after 2, 4 and 10 weeks, with a peak at two weeks (from 14.1 +/- 3.8 to 20.6 +/- 8.0/1000, P < 0.05 and from 14.3 +/- 12.4 to 29.3 +/- 54.5 mU/ml, P < 0.05, respectively). In conclusion, ACEI-related anemia in renal transplant recipients seems to be due to the erythropoietin-lowering effect of this group of drugs. A pharmacokinetic interaction between AZA and enalapril is not likely since plasma enalaprilat levels were independent of the immunosuppressive regimen and AZA metabolite levels were unchanged in the presence and absence of the ACEI. Several mechanisms by which angiotensin converting enzyme blockade may cause a decrease in circulating erythropoietin are discussed.

Defective in-vitro colony formation of haematopoietic progenitors in patients with cartilage-hair hypoplasia and history of anaemia

Cartilage-hair hypoplasia (CHH) is a metaphyseal chondrodysplasia with short-limbed short stature. The CHH gene has been recently mapped to chromosome 9, and a generalized defect in cellular proliferation has been suggested. Immunological and haematological abnormalities are common findings in CHH. In the present study erythroid, megakaryocyte, and granulocyte-macrophage colony formation in vitro by progenitors from bone marrow and blood was investigated in eight patients with CHH. All patients showed decreased erythroid and megakaryocyte colony formation. Only one patient had a normal granulocyte-macrophage growth, while the others showed decreased numbers of colonies. The defect in colony formation did not correlate with the haemoglobin concentration, platelet count or neutrophil count. The impaired growth was not caused by a decreased number of progenitors as shown by erythroid cultures. The erythroid progenitors were incapable of colony formation in culture conditions sufficient for colony formation by normal progenitors. In a more effectively stimulated culture assay the number of erythroid progenitors was normal or increased.

CONCLUSION

The present study shows defective in vitro colony formation in all myeloid lineages in patients with CHH, which is in accordance with the suggestion of a common cell proliferation defect in CHH.

Serum concentrations of erythropoietin in healthy and anaemic pregnant women

We have found serum erythropoietin (EPO) concentration significantly (p < 0.01) increased during normal pregnancy. Erythropoietin concentration was significantly (p < 0.05) higher before the 24th gestational week than after it. In pregnant women with iron deficiency anaemia serum EPO concentration was significantly (p < 0.001) higher than in healthy pregnant women. In anaemic women significant (p < 0.001) linear correlation between haemoglobin (hgb) and log serum EPO concentrations was observed. In pregnant women including both healthy and anaemic women log serum EPO concentrations correlated inversely with hgb concentrations (p < 0.01). We conclude that erythropoietin secretion is raised in normal pregnancy and is at highest in the first and second trimesters, when hgb mass begins to grow. In pregnancy with concomitant anaemia a more extensive demand for erythropoietin secretion is obvious.

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

Plasma levels of erythropoietin (mU/ml) were measured in patients with congestive heart failure (CHF) (n = 108) and in a control group of normal subjects (n = 45). In normal subjects, plasma levels of erythropoietin were 1.9 +/- 0.2. In patients with CHF, plasma levels of erythropoietin increased progressively according to New York Heart Association (NYHA) class (I: 1.4 +/- 0.2, n = 28; II: 5.4 +/- 0.8, n = 27; III: 9.6 +/- 2, n = 32; IV: 34 +/- 8, n = 21; F = 57.7, p < 0.001) and were significantly higher in NYHA classes II, III, and IV than in normal subjects. Plasma erythropoietin significantly decreased (from 43 +/- 14 to 12 +/- 3 mU/ml, p < 0.01) in patients with severe CHF (n = 9) when enalapril (20 mg/day administered orally) was added to long-term treatment for 3 weeks. Finally, in a subgroup of patients with NYHA class IV CHF (n = 9) and high plasma erythropoietin levels (37 +/- 9 mU/ml), packed red blood cell volume, assessed by the iodine-125-albumin dilution method, was higher than that in normal subjects (n = 11) (2,616 +/- 235 vs 2,028 +/- 119 ml, p < 0.05). The present study demonstrates that plasma erythropoietin levels are elevated in a large cohort of patients with CHF of varying etiology, and that this increase is related to the progression of the disease. The increase in circulating erythropoietin is associated with augmented packed red blood cell volume in patients with severe CHF. These results suggest a participation of erythropoietin in the complex neurohormonal response that occurs in CHF.

Effect of captopril on the renal veno-arterial gradient of erythropoietin and oxygen in unilateral renal artery disease

Twenty-nine patients with unilateral renal artery stenosis or occlusion were investigated. The veno-arterial gradient (VA-gradient) of erythropoietin (EPO), haemoglobin oxygen saturation and plasma renin activity (PRA) was determined separately in each kidney before and 1 h after angiotensin converting enzyme inhibition (ACE-inhibition). The VA-gradient of EPO and of hemoglobin oxygen saturation were the same in the affected and unaffected kidney during basal conditions. During ACE-inhibition the VA-gradient of EPO disappeared on the affected side but not on the unaffected side. A fall in s-EPO after ACE inhibition was demonstrated in the renal vein on the affected side (-1.4 U l-1, p < 0.01), in the contralateral vein (-0.8 U l-1, p < 0.01) and in the aorta (-0.6 U l-1, p < 0.01). The O2-gradients were reduced on both sides after captopril, from 10.8-7.5% (p < 0.04) on the affected side and from 10.8-9.0% (p < 0.04) on the contralateral. It is suggested that the stimulated renin-angiotensin system may be important for EPO production in the affected kidney in unilateral renal disease.

Elevated level of erythropoietin in congestive heart failure relationship to renal perfusion and plasma renin

BACKGROUND

In animal experiments reduction of renal perfusion can stimulate erythropoietin production. The relationship between renal haemodynamics and erythropoietin production is unknown in congestive heart failure.

OBJECTIVE

The aim was to study the relationship between serum erythropoietin and renal haemodynamics, plasma renin activity and haematocrit in patients with congestive heart failure and in healthy control subjects.

PATIENTS AND METHODS

Serum erythropoietin, renal plasma flow, glomerular filtration rate and plasma renin activity were determined in 14 patients with acyanotic congestive heart failure, and 36 healthy controls.

RESULTS

Serum erythropoietin was significantly elevated in congestive heart failure 26.6 U l-1 (median) compared with controls 17.0 U l-1 despite a normal haematocrit, and increased with the severity of congestive heart failure (New York Heart Association class II: 17 U l-1 [n = 4]; class III: 30 U l-1 [n = 5]; class IV: 45 U l-1 [n = 5]). Significant inverse correlations between serum erythropoietin and renal plasma flow (r = -0.60, P < 0.03), and between serum erythropoietin and glomerular filtration rate, were found in congestive heart failure but not in the control subjects. A significant positive correlation (r = 0.71, P < 0.03) was demonstrated between serum erythropoietin and plasma renin activity in congestive heart failure.

CONCLUSION

A severe reduction in renal perfusion in congestive heart failure appears to cause an increase in serum erythropoietin.

Successful treatment of the anemia of rheumatoid arthritis with subcutaneously administered recombinant human erythropoietin. Slower response in patients with more severe inflammation

We performed a 24-week open clinical study in which 12 patients with rheumatoid arthritis (RA) and anemia (mean hemoglobin (Hb) value 102 g/l, range 90-109 g/l) were treated with recombinant human erythropoietin (rHuEPO). rHuEPO was given as a subcutaneous injection twice weekly with an initial dose of 300 U/kg/week. Nine of the 11 patients who completed the study responded with an increase in Hb value of 15 g/l or more within 3 to 17 weeks. Three months after treatment the Hb levels were significantly lower than the highest Hb levels (p < 0.0001). There was an inverse correlation between the response rate and the mean serum concentrations of C-reactive protein and serum amyloid A protein (p < 0.001 and p < 0.003, respectively). We conclude that rHuEPO can correct anemia in patients with RA, but the response seems to be adversely influenced by the inflammatory activity of the disease.