Serum erythropoietin and its relation with soluble transferrin receptor in patients with different types of anaemia in a locally defined reference population.

Serum erythropoietin (Epo) and soluble transferrin receptor (sTR) were measured in a locally defined reference population (n=100): healthy volunteers (n=50); iron- deficiency anaemia (n=41) and haemolytic anaemia (n=9) (beta-thalassaemia, n = 4; autoimmune, n=5). Our data demonstrated an inverse relationship between erythroid activity and Epo levels. The regression line between Ln Epo and haemoglobin (Hb) was highly significant: P < 0.0001, r2=0.8275, Ln Epo=8.5346-0.04275 Hb, confidence limit 95%. The mean observed/predicted (O/P) ratio of Ln (Epo) was 1.01 +/- 0.11. We demonstrated that the serum Epo concentration in this particular population correlated consistently with clinical measures of erythropoietic activity. sTR, a new index of erythropoiesis, varied from 16.1 to 148 nmol/l, mean 62.0 nmol/l in the anaemic patients' group. The relationship between Ln Epo and Ln sTR was highly significant: P < 0.0001. We conclude that locally defined regression analyses are crucial for correct data interpretation and can indicate whether or not Epo production is appropriate or inappropriate. Serial determinations of sTR could help in the assessment of response to therapeutic doses of Epo.     

Serum erythropoietin and its relation with soluble transferrin receptor in patients with different types of anaemia in a locally defined reference population

Serum erythropoietin (Epo) and soluble transferrin receptor (sTR) were measured in a locally defined reference population (n=100): healthy volunteers (n=50); iron‐ deficiency anaemia (n=41) and haemolytic anaemia (n=9) (β‐thalassaemia, n= 4; autoimmune, n=5). Our data demonstrated an inverse relationship between erythroid activity and Epo levels. The regression line between Ln Epo and haemoglobin (Hb) was highly significant: P < 0.0001, r²=0.8275, Ln Epo=8.5346–0.04275 Hb, confidence limit 95%. The mean observed/predicted (O/P) ratio of Ln (Epo) was 1.01 ± 0.11. We demonstrated that the serum Epo concentration in this particular population correlated consistently with clinical measures of erythropoietic activity. sTR, a new index of erythropoiesis, varied from 16.1 to 148 nmol/l, mean 62.0 nmol/l in the anaemic patients’ group. The relationship between Ln Epo and Ln sTR was highly significant: P < 0.0001. We conclude that locally defined regression analyses are crucial for correct data interpretation and can indicate whether or not Epo production is appropiate or inappropiate. Serial determinations of sTR could help in the assessment of response to therapeutic doses of Epo.     

Serum erythropoietin levels in paroxysmal nocturnal haemoglobinuria: implications for therapy

In order to assess the rationale and possible indications for the use of recombinant erythropoietin in paroxysmal nocturnal haemoglobinuria (PNH), we have measured endogenous erythropoietin (Epo) levels in 18 patients with PNH and in 44 patients with iron deficiency anaemia (IDA). In both groups of patients we found a significant inverse correlation between Epo and haemoglobin (Hb). However, the mean Epo level was significantly higher in the PNH group (385 mU/ml) than in the IDA group (136 mU/ml). The range of Epo levels at any given Hb was greater in the PNH group than in the IDA group. There was a significant positive correlation between Epo and absolute reticulocyte count. Since Epo administration is unlikely to benefit patients with high levels of endogenous Epo, we conclude that in the majority of patients with PNH there is no indication for treatment with Epo.     

Blunted erythropoietin response to anaemia in tuberculosis

Abstract: The precise cause of the anaemia that is commonly associated with severe pulmonary tuberculosis (PTB) has not been elucidated. The role of erythropoietin (Epo), the central hormone regulating red cell formation, still awaits clarification. We therefore determined serum Epo levels in patients with PTB; group 1, haemoglobin less than 110 g/L, group 2, haemoglobin greater than 110 g/L; group 3, controls, consisted of matched individuals with uncomplicated iron deficiency; group 4, healthy volunteers. Peripheral blood monocytes were obtained from patients with PTB and the controls, cultured, and the supernatant fluid (SNF) harvested. Tumour necrosis factor alpha (TNFα) levels were determined in the SNF, which were then added in various dilutions to a hepatocellular carcinoma cell line (HepG2) capable of regulated EPO synthesis in vitro. The influence of this cytokine was defined by the addition of specific neutralising anti-TNFα antibodies in this assay system. Patients in group 1 had significantly lower Epo levels (54 ± 11 mU/mL) compared with those in group 3 (142 ± 41 mU/mL) (p<0.01). Monocyte supernatants from patients in the anaemic PTB group had markedly elevated TNFα levels and significantly suppressed Epo output by HepG2 cells in vitro (p<0.01). This inhibition was consistently abrogated by anti-TNFα antibodies. Serum Epo levels were inappropriately low in untreated PTB patients when compared with corresponding haemoglobin levels in iron deficient controls. This blunted response could be ascribed to release of TNFα or other cytokines by activated monocytes.     

Blunted erythropoietin production and defective iron supply for erythropoiesis as major causes of anaemia in patients with chronic heart failure.

AIMS: Anaemia is often observed in patients with chronic heart failure (CHF), and it may be associated with a worse prognosis. Aim of this study was to identify the individual mechanisms of anaemia in CHF patients. METHODS AND RESULTS: One hundred and forty-eight consecutive patients with haemoglobin concentration <13 g/dL (if males) or <12 g/dL (if females) were enrolled. Factors responsible for anaemia were investigated by evaluating endogenous erythropoietin (Epo) production, serum cytokines levels, body iron status, and iron supply for erythropoiesis. Most patients (57%) presented anaemia of chronic disease and among them, 92% showed evidence of a defective endogenous Epo production. This was indicated by an observed/predicted log(serum Epo) ratio less than 0.8 and/or a defective iron supply for erythropoiesis diagnosed by low transferrin saturation and/or increased value of soluble transferrin receptor. According to regression analysis sex, renal failure, and serum Epo were correlated with anaemia. CONCLUSION: According to our study, about half of anaemic CHF patients showed anaemia of chronic disease with blunted endogenous Epo production and/or a defective iron supply for erythropoiesis. Determination of the individual mechanisms of anaemia in CHF could justify a rational therapeutic approach to anaemia.     

Serum erythropoietin in chronic lymphocytic leukaemia

Anaemia is a frequent complication of advanced chronic lymphocytic leukaemia (CLL) and several cytokines known to inhibit erythropoietin (Epo) formation are produced by CLL B cells. Therefore we measured serum Epo levels in 47 CLL patients to determine whether Epo was a significant factor in the development of their anaemia. Epo levels were increased compared to normal individuals and this elevation appeared adequate for the degree of anaemia. The slope of the regression of Epo versus haemoglobin (Hb) was similar to that of a reference group. Serum transferrin receptor (sTfR) levels were also appropriately elevated for the degree of anaemia and correlated with serum Epo. Advanced stage was not associated with reduction of Epo production but diminished erythropoietic activity was observed in several patients. The results indicate that anaemia in CLL is not characterized by inadequate Epo production.     

Serum erythropoietin concentration in anaemia of visceral leishmaniasis (kala-azar) before and during antimonial therapy

Serum erythropoietin (Epo) concentrations and variables of red cell and iron status were studied in 27 Sudanese patients who were treated with sodium stibogluconate for visceral leishmaniasis (kala-azar). Blood haemoglobin increased from 6.4 (±1.7 SD) to 9.5 (±1.4) g/dl during treatment. Serum ferritin decreased concomitantly. Serum iron levels were unchanged whereas the total iron binding capacity increased slightly. The pre-treatment serum Epo concentration in relation to the blood haemoglobin concentration was not as high as expected from the one in primary haematological diseases, indicating that there is a relative lack of Epo in anaemic kala-azar patients. Serum Epo further decreased during stibogluconate therapy. The normal dependence of the serum Epo level on the blood haemoglobin concentration was lost during mid-term antimonial treatment, but it recovered thereafter. Cell culture studies with the human hepatoma cells HepG2 showed that stibogluconate ( 30 μg/ml) inhibited Epo gene expression. Thus, effective treatment of kala-azar with stibogluconate results in improvement of anaemia, although the drug itself may impair Epo production.     

Decreased erythropoietin response in Plasmodium falciparum malaria-associated anaemia

Abstract: One of the most serious manifestations of Plasmodium falciparum malaria is anaemia. Its established causes are increased red cell destruction and ineffective erythropoiesis. Since proinflammatory cytokines have been shown to suppress the in vitro synthesis of erythropoietin (Epo), we measured serum immunoreactive Epo in 90 Sudanese patients suffering from malaria. Even in severe cases of anaemia (blood haemoglobin <80 g/l), serum Epo levels rarely exceeded 300 U/l. For comparison, serum Epo was increased up to 12,000 U/l in a reference group of Caucasian patients with anaemia not associated with infection. Moreover, the slope of the log Epo/haemoglobin regression line was less steep in malarial anaemia. Thus, as documented for other chronic inflammatory disorders, there is a relative lack of Epo in malaria-associated anaemia. Treatment with the antimalarial drug chloroquine may aggravate the defect in Epo production, because chloroquine inhibited Epo synthesis when tested in cell culture.     

Erythropoietin production and erythropoiesis in compensated and anaemic states of hereditary spherocytosis

A compensated haemolytic state is defined by decreased red cell life-span without anaemia, i.e. by increased erythropoiesis in the absence of the physiological stimulus for erythropoietin (Epo) production. We evaluated s-Epo levels and the expansion of erythropoiesis (as measured by circulating transferrin receptor, s-TfR) in 32 patients with hereditary spherocytosis (HS) with the aim of verifying whether the enhanced erythropoiesis of compensated haemolysis was Epo-dependent. 20 of the patients (62.5%) had normal Hb values (> 12 g/dl in females and > 13 g/dl in males). Their compensated haemolytic state was the result of up to 8.2 times normal s-Epo and up to 3.9 times normal s-TfR levels, which were maintained by physiological regulation of erythropoiesis, as documented by the inverse dependence of Hb on s-Epo levels. Considering that patients with iron-deficiency anaemia represented the predicted physiological Epo response to anaemia, the observed/predicted ln s-Epo ratio (O/P ratio) was calculated in HS patients with anaemia and was used as an index of the adequateness of Epo production. All the anaemic HS patients had an O/P ratio > 1, documenting inappropriately high s-Epo levels. This work demonstrates that the compensated haemolytic state of HS patients is produced by an inappropriately high s-Epo level, and that the pattern of Epo overproduction is a biological characteristic of the disease.     

Plasma erythropoietin levels in anaemic and non-anaemic patients with chronic liver diseases

AIM: To investigate the serum erythropoietin (Epo) levels in patients with chronic liver diseases and to compare to subjects with iron-deficiency anaemia and healthy controls. METHODS: We examined 31 anaemic (ALC) and 22 non-anaemic (NALC) cirrhotic patients, 21 non- anaemic subjects with chronic active hepatitis (CAH), 24 patients with iron-deficiency anaemia (ID) and 15 healthy controls. Circulating Epo levels (ELISA; R and D Systems, Europe Ltd, Abingdon, UK) and haemoglobin (Hb) concentration were determined in all subjects. RESULTS: Mean+/-SD of Epo values was 26.9+/-10.8 mU/mL in ALC patients, 12.5+/-8.0 mU/mL in NALC subjects, 11.6+/-6.3 mU/mL in CAH patients, 56.4+/-12.7 mU/mL in the cases of ID and 9.3+/-2.6 mU/mL in controls. No significant difference (P>0.05) was found in Epo levels between controls, CAH and NALC patients. ALC individuals had higher Epo levels (P<0.01) than these groups whereas ID subjects had even higher levels (P<0.001) than patients suffering from ALC. CONCLUSION: Increased Epo values in cirrhotics, are only detectable when haemoglobin was lesser than 12 g/dL. Nevertheless, this rise in value is lower than that observed in anaemic patients with iron-deficiency and appears blunted and inadequate in comparison to the degree of anaemia.     

Erythrocytosis due to a mutation in the erythropoietin receptor gene

Familial erythrocytosis, associated with high haemoglobin levels and low serum erythropoietin (Epo), has been shown to co-segregate with a sequence repeat polymorphism at the 5' region of the erythropoietin receptor (EpoR) in a large Finnish family.   We have investigated the cause of erythrocytosis in an English boy. Sequencing of the cytoplasmic region of the EpoR detected a de novo transition mutation of G to A at nucleotide 6002. This mutation resulted in the formation of a stop codon at amino acid 439 with the loss of 70 amino acids from the carboxy terminus. The mutation (G6002A) has arisen independently in a Finnish family and de novo in this English boy. Patients with unexplained erythrocytosis and low serum Epo levels should be investigated for EpoR mutations.     

Air trapping: The major factor limiting diaphragm mobility in chronic obstructive pulmonary disease patients

Background and objective:   Patients with COPD can have impaired diaphragm mechanics. A new method of assessing the mobility of the diaphragm, using ultrasound, has recently been validated. This study evaluated the relationship between pulmonary function and diaphragm mobility, as well as that between respiratory muscle strength and diaphragm mobility, in COPD patients.
Methods:   COPD patients with pulmonary hyperinflation ( n  = 54) and healthy subjects ( n  = 20) were studied. Patients were tested for pulmonary function, maximal respiratory pressures and diaphragm mobility using ultrasound to measure the craniocaudal displacement of the left branch of the portal vein.
Results:   COPD patients had less diaphragm mobility than did healthy individuals (36.5 ± 10.9 mm vs 46.3 ± 9.5 mm, P  = 0.001). In COPD patients, diaphragm mobility correlated strongly with pulmonary function parameters that quantify air trapping (RV: r  = −0.60, P  < 0.001; RV/TLC: r  = −0.76, P  < 0.001), moderately with airway obstruction (FEV₁: r  = 0.55, P  < 0.001; airway resistance: r  = −0.32, P  = 0.02) and weakly with pulmonary hyperinflation (TLC: r  = −0.28, P  = 0.04). No relationship was observed between diaphragm mobility and respiratory muscle strength (maximal inspiratory pressure: r  = −0.11, P  = 0.43; maximal expiratory pressure: r  = 0.03, P  = 0.80).
Conclusion:   The results of this study suggest that the reduction in diaphragm mobility in COPD patients is mainly due to air trapping and is not influenced by respiratory muscle strength or pulmonary hyperinflation.     

Age-related changes in plasma androgen levels and their association with cardiovascular risk factors in male Japanese office workers

Aim:   To assess the age-related change in plasma androgen levels in healthy middle-aged men and whether any clinical parameters are associated with the hormonal change.
Methods:   The study was comprised of male Japanese office-workers aged 40–64 years, who had undergone an annual health check-up in 2002 and 2007 (96 and 76 men, respectively). Body mass index and blood pressure were measured, and serum concentration of lipids, glucose and uric acid in addition to plasma total testosterone, free testosterone and dehydroepiandrosterone sulfate (DHEA-S) levels were determined in the morning after an overnight fast. The 5-year hormonal changes and their associations with clinical parameters were analyzed in 33 men who repeated the examination at both check-ups. The cross-sectional associations of hormonal levels with clinical parameters were also investigated.
Results:   Age was negatively associated with free testosterone ( r  = −0.399, P  < 0.001 in 2002; r  = −0.458, P  < 0.001 in 2007) and DHEA-S ( r  = −0.233, P  = 0.02 in 2002; r  = −0.336, P  < 0.01 in 2007) but not with total testosterone, while the 5-year changes of free testosterone and DHEA-S levels were not significant and showed no associations with major cardiovascular risk factors. Cross-sectionally, after adjustment for age, linear regression analysis showed a positive association between free testosterone and blood hemoglobin and a negative association between total testosterone and serum uric acid.
Conclusion:   In Japanese middle-aged men, 5-year androgen decline is too subtle to detect, and endogenous androgen levels seem to have relatively weak association with cardiovascular risk profiles.     

Circulating erythropoietin in patients with myelodysplastic syndromes

Serum concentration of erythropoietin (Epo) has been measured by radioimmunoassay in 46 patients with myelodysplastic syndromes. There is an overall inverse relationship between the level of Epo and the degree of anaemia but a wide range of Epo response between patients with similar haemoglobin concentrations. No differences were found between the different FAB groups, but the highest Epo levels were found in those patients with erythroid hypoplasia in the bone marrow. It is suggested that the intensity of erythroid activity in the marrow, as well as the degree of anaemia, may be a factor determining serum Epo concentration.     

Serum erythropoietin levels in paroxysmal nocturnal haemoglobinuria: implications for therapy

In order to assess the rationale and possible indications for the use of recombinant erythropoietin in paroxysmal nocturnal haemoglobinuria (PNH), we have measured endogenous erythropoietin (Epo) levels in 18 patients with PNH and in 44 patients with iron deficiency anaemia (IDA). In both groups of patients we found a significant inverse correlation between Epo and haemoglobin (Hb). However, the mean Epo level was significantly higher in the PNH group (385 mU/ml) than in the IDA group (136 mU/ml). The range of Epo levels at any given Hb was greater in the PNH group than in the IDA group. There was a significant positive correlation between Epo and absolute reticulocyte count. Since Epo administration is unlikely to benefit patients with high levels of endogenous Epo, we conclude that in the majority of patients with PNH there is no indication for treatment with Epo.     

Serum erythropoietin in rheumatoid arthritis and other inflammatory arthritides: relationship to anaemia and the effect of anti-inflammatory treatment

Serum erythropoietin (s-Epo) was measured with a sensitive radioimmunoassay method in 58 patients with classical rheumatoid arthritis (n = 41) or seronegative spondyloarthropathies (n = 17). Epo was significantly (P less than 0.001) increased and on an average two times higher than in a healthy population. A correlation was found between Hb and s-Epo (r = -0.46, P less than 0.005), indicating that these patients respond to anaemia with an increase in s-Epo. In order to investigate if inflammation has a direct influence on s-Epo levels a short period of corticosteroid treatment was given to rapidly decrease inflammatory activity. No increase in s-Epo was seen after 1 week. Furthermore, there was a correlation between s-Epo and ESR in all patients (r = 0.59, P less than 0.01). These results indicate that s-Epo is directed by the Hb level, which in turn is influenced by the inflammatory activity: a higher inflammatory activity gives a lower Hb and an increase in s-Epo. In comparison to previously published figures for the relation between Hb and s-Epo these patients seem to have an ordinary Epo response. We conclude that the anaemia of patients with chronic inflammatory joint disease is not caused by a diminished Epo production.     

Increase of haemoglobin levels by anti-retroviral therapy is associated with a decrease in immune activation

DESIGN: We evaluated whether an increase in haemoglobin levels in the first 6 months of effective anti-retroviral therapy (ART) is associated with a decrease in immune activation. To reduce confounding factors only men (n = 35) and patients not receiving agents known to enhance haematopoiesis or patients without diseases that might suppress haematopoiesis were included. Simultaneously parameters of iron metabolism and cofactors for haematopoiesis were analysed. RESULTS: A median baseline haemoglobin level of 139 g L-1 increased to 149 g L-1 at month 6 of ART (P < 0.001). At baseline low haemoglobin levels were strongly associated with high neopterin concentrations (r = - 0.64, P < 0.001), and much less correlated to high HIV-1 RNA levels (r = - 0.41, P < 0.05) and to a lower CD4+ cell count (r = 0.33, P < 0.05). The change of neopterin levels during the study period correlated with the relative change in haemoglobin levels, r = - 0.35, P = 0.03, whereas no such correlations were found for the change of HIV-1 RNA levels and the CD4 cell count. A logistic regression analysis revealed that the change of neopterin and soluble transferrin receptors concentrations are independently associated with an increase of haemoglobin levels of more than 15 g L-1. CONCLUSION: Our study supports a cause-effect relationship between immune activation and anaemia in HIV-infected patients. Treatment of patients with ART decreases virus load, which may thereby result in silencing of immune effector activity thus ameliorating anaemia by reversing the anti-proliferative effects of cytokines towards erythroid progenitors and the iron withdrawal strategy of the immune system.     

Renal impairment and anaemia in a population-based study of older people

Abstract
Background: Established renal failure is a known cause of anaemia. However, the association between more modest levels of renal impairment and anaemia is unclear.
Aims: The aim of the present study was to investigate the association between mild renal impairment and anaemia in the general population.
Methods: A population-based, cross-sectional study was conducted in the general community in an urban area of the Blue Mountains, just west of Sydney, Australia. The study included 3222 people aged ≥49 years (mean age 65 years). Serum creatinine and haemoglobin were measured using standard laboratory techniques. Creatinine clearance was estimated from serum creatinine, body weight, sex and age.
Results:  Two hundred and seventy subjects (8.4%) had serum creatinine levels ≥125 µmol/L and estimated ­creatinine clearances were <0.84 mL/s (50 mL/min) in 894 subjects (27.7%) and <0.50 mL/s (30 mL/min) in 120 subjects (3.7%). There was a strong association between reduced renal function and anaemia. Compared to those with serum creatinine <125 µmol/L, the age-adjusted relative risk (RR) of anaemia in women (haemoglobin <12.0 g/dL) with serum creatinine ≥125 µmol/L was 5.5 (95% confidence interval (CI) 2.9−10.7) and the RR of anaemia in men (haemoglobin < 13.0 g/dL) was 3.1 (95% CI 1.6−6.0). Estimated ­creatinine clearance <50 mL/min was associated with a three-fold increased risk of anaemia in women and a five-fold increased risk in men.
Conclusions: The results of the present study suggest that even modestly impaired renal function is associated with anaemia in older men and women. The possibility of renal impairment should be considered in the diagnosis and management of anaemia in people aged>50 years. (Intern Med J 2004; 34: 20−23)     

Erythropoietin response to anaemia in children with sickle cell disease and Fanconi's hypoproliferative anaemia

The erythropoietin response to anaemia was compared in 30 children with haemolytic anaemia and in 5 children with Fanconi's hypoproliferative anaemia. Serum erythropoietin was measured by radioimmunoassay. In children with haemolytic anaemia the serum erythropoietin concentration increased exponentially with decreasing haematocrit values (r = 0.74; p less than 0.001). Serum erythropoietin levels also correlated with reticulocyte counts (r = 0.62; p less than 0.001). Children with Fanconi's hypoproliferative anaemia had considerably higher serum erythropoietin levels than children with haemolysis for the same degree of anaemia. These data indicate that erythropoietin production in Fanconi's anaemia may be dependent on other factors in addition to the degree of anaemia and relative hypoxaemia.     

Serum testosterone levels correlate with haemoglobin in middle-aged and older men

Background: Lower testosterone levels are associated with anaemia in older men and women. The relation between testosterone and haemoglobin (Hb) in younger and middle-aged men is less well defined. The aim of the study was to examine the association between testosterone and Hb levels in men spanning middle to older ages.
Methods: A cross-sectional analysis of 492 men aged 30.7–94.5 years from the Busselton Health Survey, Western Australia, was carried out. Haemoglobin (Hb), early-morning serum total testosterone and sex hormone-binding globulin (SHBG) were measured. Free testosterone was calculated using mass action equations.
Results: Haemoglobin correlated to total and free testosterone concentrations ( r = 0.13, P = 0.003 and r = 0.20, P < 0.001, respectively). Hb and SHBG were inversely correlated ( r =−0.14, P = 0.001). Hb increased across lowest to highest quartiles of total testosterone ( P = 0.02) and free testosterone ( P < 0.001), but not SHBG. After adjusting for age, waist circumference, smoking status, alcohol consumption, renal function and ferritin, total testosterone was associated with Hb ( β = 0.037, P = 0.003) as was free testosterone ( β = 2.32, P < 0.001), whereas SHBG was not associated.
Conclusion: Testosterone concentration modulates Hb levels in community-dwelling men across a wide age range. Further studies are needed to clarify implications of this association between testosterone and Hb in men.