High altitude residents
Andrew M. Luks, Philip N. Ainslie, Justin S. Lawley, Robert C. Roach, Tatum S. Simonson in Ward, Milledge and West's High Altitude Medicine and Physiology, 2021
Increasing numbers of people are living permanently at high altitude. High-altitude residents of the South American Andes, the Tibetan plateau, and Ethiopia highlands who have existed at altitude for hundreds of generations have developed distinct adaptive and maladaptive strategies while living in their respective hypoxic environments. Hemoglobin concentration is a defining feature in the differential manifestations of adaptation between high altitude Andeans and Tibetans. Increased hemoglobin-oxygen binding affinity has typically been regarded as beneficial at altitude by enhancing the rate of equilibration across the alveolar-capillary barrier. It has been widely assumed that lower hemoglobin concentration in Tibetans is achieved via the absence of a significant erythropoietic response to hypoxemia. The chapter concludes with a review of another important issue for residents of high altitude regions, the burden of non-communicable and communicable diseases and how this burden is changing over time.
Iron
Howerde E. Sauberlich in Laboratory Tests for the Assessment of Nutritional Status, 2018
Iron deficient erythropoiesis has been defined as a state in which the supply of iron is inadequate to support optimal erythropoiesis in the developing red cell mass. Most of the iron in these items is present as heme iron, which has a high bioavailability. Iron is a constituent of hemoglobin, myoglobin, cytochromes, and a number of other proteins which function in the utilization, transport, and storage of oxygen. Serum transferrin receptor assays provide more reliable information on iron status since non-nutritional factors and chronic diseases have little effect on transferrin receptor status. Hemoglobin concentrations and/or hematocrit values are relatively insensitive indices that detect only the more severe states of iron deficiency. The impaired cognitive performance and decreased work capacity that may occur with an iron deficiency at any age is particularly disconcerting. Plasma iron levels and transferrin saturation levels are useful for screening purpose but can be misleading because of influences by other clinical disorders.
Idiopathic Pulmonary Hemosiderosis
Lourdes R. Laraya-Cuasay, Walter T. Hughes in Interstitial Lung Diseases in Children, 2019
Pulmonary hemosiderosis (PH) is a rare disease which primarily affects children and adolescents, and was described first by Virchow in 1864. It is characterized by acute and chronic blood loss which occurs from pulmonary capillaries and often results in the triad of hemoptysis, interstitial pulmonary infiltrates, and anemia. The presentation and clinical course of idiopathic PH (IPH) are variable and depend upon the intensity, duration and frequency of the hemorrhages. Chronic and acute blood loss occurs in IPH, and since the iron contained in hemosiderin trapped within the lung is only scantily reutilized for erythropoiesis, iron deficiency anemia develops in most cases. Pulmonary functions improve during remissions, and may revert to normal before interstitial fibrosis supervenes. Cardiovascular disease leading to pulmonary venous hypertension, especially mitral valve stenosis, can cause diffuse pulmonary hemorrhage and PH. Pulmonary symptoms generally precede renal involvement, and although the clinical course is variable, the disease is often fatal despite treatment with corticosteroids, immunosuppressives and plasmapheresis.
A Case of Erythropoietic Protoporphyria
Published in Baylor University Medical Center Proceedings, 2016
Kathryn Lindsey, Micah Burch, John R. Krause
A 53-year-old Texas rancher developed a blistering skin rash that was sensitive to exposure to sunlight. He was referred to hematology with a presumptive diagnosis of porphyria. His peripheral blood counts were within normal limits, and a bone marrow examination revealed erythroid dyspoiesis and ringed sideroblasts. Serum, plasma, and erythrocyte protoporphyrin levels were elevated, the findings of which are consistent with a diagnosis of erythropoietic protoporphyria. This paper discusses the diagnosis and etiology of the porphyrias.
Effects of erythropoietin abuse on exercise performance
Published in The Physician and Sportsmedicine, 2018
Paolo Sgrò, Massimiliano Sansone, Andrea Sansone, Francesco Romanelli, Luigi Di Luigi
The present review provides a comprehensive overview on the erythropoietic and non-erythropoietic effects of rHuEpo on human sport performance, paying attention to quantifying numerically how rHuEpo affects exercise performance and describing physiological changes regarding the most important exercise variables. Much attention has been paid to treatment schedules, in particular, to assess the effects of microdoses of rHuEpo and the prolonged effects on sport performance following withdrawal. Moreover, the review takes into account non-erythropoietic ergogenic effects of rHuEpo, including cognitive benefits of rHuEpo. A significant increase in both Vo2max and maximal cycling power was evidenced in studies taken into account for this review. rHuEpo, administered at clinical dosage, may have significant effects on haematological values, maximal and submaximal physiological variables, whereas few reports show positive effects on exercise perfomance. However, the influence of micro-dose rHuEpo on endurance performance in athletes is still unclear and further studies are warranted.
Drug safety profile of darbepoetin alfa for anemia of chronic kidney disease
Published in Expert Opinion on Drug Safety, 2009
Anemia of chronic kidney disease due to deficiency of erythropoietin is common and has clinical consequences. Erythropoiesis stimulating agents including darbepoetin alfa (DA) are effective in correcting anemia. DA is generally well tolerated and has side effect profile similar to recombinant human erythropoietin. It has a long half-life permitting infrequent dosing. DA has been tested extensively in preclinical and clinical studies and significant experience has accumulated in clinical practice. Global safety profile of DA must consider recent data indicating worse survival, poor cardiovascular outcomes and thrombotic risks of targeting near normal hemoglobin levels and administering high doses of erythropoiesis stimulating agents. Strategies to achieve and maintain a reasonable, individualized target hemoglobin level with minimal variations in hemoglobin level are needed.