PubMed · 15658388
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Katsumi Higashi. 2004. [Reticulocyte].. https://pubmed.ncbi.nlm.nih.gov/15658388/
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Both polycythemia and the increase in hypoxic ventilatory response (HVR) are considered as important factors of acclimatization to hypoxia. The objective of this study was to characterise the ventilation pattern at different inspired oxygen fraction in a model of chronic anemic mice. These mice have a targeted disruption in the 5' untranslated region of the Epo gene that reduces Epo expression such that the homozygous animal is severely anemic. Ventilation in normoxia in Epo-TAg(h) mice was significantly greater than in wild type, and the difference was mainly due to a higher tidal volume. HVR was higher in Epo-TAg(h) mice at every FIO2 suggesting a higher chemosensitivity. Resting oxygen consumption was maintained in anemic mice. Maximal oxygen consumption was 30% lower while hemoglobin was 60% lower in anemic mice compared to wild type. This small decrease in maximal oxygen consumption is probably due a greater cardiac output and/or a better tissue oxygen extraction and would allow these anemic mice to acclimatize to hypoxia in spite of low oxygen carrying capacity. In conclusion, Epo-TAg(h) anemic mice showed increased ventilation and hypoxic ventilatory response. However, whether these adaptations will contribute to acclimatization in chronic hypoxia remains to be determined.
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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.