Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0240066 (iron deficiency)
 7,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The prevalence of anaemia in patients with cancer lies between 10 and 40%, depending on the type of tumor and chemotherapy. Anaemia has a significant impact on the quality of life, along with pain or disease progression. There are multiple causes but the physiopathology resembles that of inflammatory anaemia. The following mechanisms can be distinguished: a resistance of the erythroid precursor cells (BFU-e, CFU-e) to erythropoietin, an inappropriately decreased renal erythropoietin secretion for a given haemoglobin value and alterations of the iron metabolism leading to a functional iron deficiency. Recombinant human erythropoietin (r-hu-EPO) is safe and efficient in the treatment of anaemia of chronic renal failure and rheumatoid arthritis. In oncology different phase I and II studies have demonstrated an efficacy (increase of haemoglobin, decrease of transfusion requirements) in about 50% of all adult patients. A response to a subcutaneous r-hu-EPO treatment with a relatively high posology of 150 U/kg three times a week can be expected after one to two months. No single reliable parameter will predict a response to the r-hu-EPO treatment. Several phase III studies confirm that anaemia in cancer patients undergoing chemotherapy (notably with cisplatin) can be corrected in 40 to 60% of all cases and that the haemoglobin increase improves the quality of life. Finally, recent clinical trials suggest that an early r-hu-EPO treatment might prevent the occurrence of anaemia secondary to chemotherapy. Several parameters will have to be specified such as the precise definition of the groups at risk, the appropriate haemoglobin level to initiate a r-hu-EPO treatment, its optimal posology, as well as the role of the iron substitution and its route of administration. The impact of the r-hu-EPO treatment on the quality of life of cancer patients constitutes a priority for future studies, which will have define the exact role of r-hu-EPO in oncology management.
 ...
PMID:[Tumor anemia. Overview of the role of human recombinant erythropoietin (r-hu-EPO) in treatment of tumor anemia]. 1006 75

This article, based on our own studies and those of others, presents evidence to show that the anemia of chronic renal failure in the predialysis period is, to a significant extent, caused by iron deficiency and can be improved in most cases by the administration of intravenous (i.v.) but not oral iron. We estimate that in approximately 30% of all predialysis patients with anemia, a target hematocrit (Hct) of 35% can be reached and maintained by giving i.v. iron alone without exceeding currently acceptable limits of serum ferritin (500 microg/liter) or the percentage of iron saturation (40%). If, in addition, subcutaneous erythropoietin (EPO-usually in only low doses-is added, the combination has an additive effect on the Hct response, and almost all anemic predialysis patients can reach and maintain the target Hct of 35% over a one-year period. Therefore, the advantage of maintaining adequate iron stores with i.v. iron is that if EPO is needed, lower doses will be required to achieve the target Hct than if EPO were used alone. This not only avoids the high cost of EPO therapy but also its associated side-effects, especially hypertension. Using Venofer, a ferric hydroxide sucrose complex, as our i.v. iron supplement, we have seen no anaphylactic reactions in over 20,000 infusions over a four-year period in 360 hemodialysis, 123 predialysis, and 58 peritoneal dialysis patients.
 ...
PMID:Intravenous iron for the treatment of predialysis anemia. 1008 91

Iron deficiency is the most frequently encountered cause of suboptimal response to recombinant human erythropoietin (rHuEPO). Carefully assessing iron status is of paramount importance in chronic renal failure patients prior to or during rHuEPO therapy. Because there is great need for iron in the EPO-stimulated erythroid progenitors, it is essential that serum ferritin and transferrin saturation levels should be maintained over 300 microg/liter and 30%, respectively. Investigators have shown that oral iron is unlikely to keep pace with the iron demand for an optimal rHuEPO response in uremics. Therefore, patients with iron deficiency will always require intravenous iron therapy. The early and prompt iron supplementation can lead to reductions in rHuEPO dose and hence cost. After the iron deficiency has been corrected or excluded, we must remember all of the possible causes of hyporesponsiveness in every rHuEPO-treated patient. As dose requirements vary, it is not clear which dose of rHuEPO causes this hyporesponsiveness. However, if the patient with iron repletion does not respond well after the induction period, the major causes blunting the response to rHuEPO should be investigated. Most factors are reversible and remediable, except resistant anemia associated with hemoglobinopathy or bone marrow fibrosis, which requires a further increase in the rHuEPO dose. By means of early detection and correction of the possible causes, the goal of increasing therapeutic efficacy can be achieved. Iron overload may lead to an enhanced risk for infection, cardiovascular complication, and cancer. Over-treatment with iron should be avoided in dialysis patients, despite the fact that the safe upper limit of serum ferritin to avoid iron overload is not clearly defined. On the other hand, functional iron deficiency may develop even when serum ferritin levels are increased. Controversy remains as to whether intravenous iron therapy can overcome this form of hyporesponsiveness in iron-overloaded patients. Moreover, a treatment option of iron supplementation is not warranted in these patients, as the potential hazards of iron overload will be worsened. We demonstrated that the mean hematocrit significantly increased from 25.1+/-0.9% to 31+/-1.2% after eight weeks of intravenous ascorbate therapy (300 mg three times a week) in 12 hemodialysis patients with serum ferritin levels of more than 500 microg/liter. The enhanced erythropoiesis paralleled with a rise in transferrin saturation (27.8+/-2.5% vs. 44.8+/-9.5%, P < 0.05) and reductions in erythrocyte zinc protoporphyrin (130+/-32 vs. 72+/-19 micromol/mol heme, P < 0.05) and monthly rHuEPO dose (24.2+/-4.5 vs. 16.8+/-3.4 x 10(3) units, P < 0.05) at the end of study. It is speculated that ascorbate supplementation not only facilitates the iron release from storage sites and its delivery to hematopoietic tissues, but also increases iron utilization in erythroid cells. Our study provides a more complete understanding of the pathogenesis of iron overload-related anemia and the development of an adjuvant therapy, intravenous ascorbic acid, to the existing treatments.
 ...
PMID:Erythropoietin hyporesponsiveness: from iron deficiency to iron overload. 1008 94

Treatment of anemia in children with end-stage renal disease (ESRD) has been greatly facilitated by the introduction of recombinant human erythropoietin (rHuEPO). A major limiting factor in the treatment of renal anemia is sufficient iron supplementation. Eight children (aged 10-17 years) receiving hemodialysis were treated with intravenous iron (1 mg/kg per week) for 3 months. Hemoglobin (Hb), hematocrit (Hct), and serum ferritin levels were measured regularly. The mean Hct increased from 25% to 30%, the mean Hb increased from 7. 8 g/dl to 9.2 g/dl, and the mean ferritin level from 200 to 395 mg/dl. The mean EPO dosage could be tapered from 6,500 IU to 6,150 IU. No adverse side-effects were noted. Hence, in this uncontrolled study intravenous iron was an effective treatment for iron deficiency during rHuEPO therapy in children with ESRD on hemodialysis.
 ...
PMID:Intravenous iron treatment of renal anemia in children on hemodialysis. 1046 May 5

Recombinant human erythropoietin (rhEPO), which increases red cell mass, is one of the most abused substances in sport. Abuse is currently undetectable by the only direct routine method, immunoassay, since blood and urine rhEPO are immunologically indistinguishable from endogenous EPO. Elevated EPO levels are only detectable several days after rhEPO administration. Indirect parameters have therefore been introduced, primarily the haematocrit level, but also markers of functional iron deficiency during or after rhEPO administration (hypochromic red cells and reticulocytes, serum transferrin receptors, ferritin levels) and, in the urine, fibrin degradation products. Although iron status indices have yielded promising results, athletes are currently banned solely on the basis of their haematocrit. Yet various factors can cause false positive haematocrit results with potentially fatal consequences to athletes' careers. Until new direct assays such as liquid chromatography-mass spectrometry have been evaluated and introduced, efforts must be directed at using a battery of tests to increase the sensitivity and specificity and reduce the number of false positives and false negatives.
 ...
PMID:Erythropoietin test methods. 1093 16

Recombinant human erythropoietin (rHuEPO) has revolutionized the treatment of anemia of chronic renal failure. RHuEPO has been shown to increase survival, decrease hospitalizations, improve brain and cognitive function, and improve quality of life for renal patients. Much has been learned about the normal and pathologic physiology of anemia because rHuEPO has become available to investigators, and this has been widely applied. Additional work is needed in better defining the sites of production of endogenous EPO as well as the nature and control of the oxygen sensor(s) in the kidney. Remaining clinical issues related to this remarkable compound include predicting and overcoming resistance; avoiding iron deficiency; determining the appropriate target hemoglobin; increasing the use strategies such as subcutaneous administration to increase efficiency; and devising a more rational payment scheme.
 ...
PMID:Erythropoietin and anemia. 1124 80

We showed that the content of reticulocyte hemoglobin (CHr) is a reliable measure of iron status with regard to erythrocytopoiesis in chronic dialysis status. The mean CHr level was 32.3 +/- 2.2 pg in dialysis patients and CHr was significantly correlated with the conventional parameters of iron deficiency. We aimed to utilize the measurement of CHr levels to monitor iron status in clinical practice. We measured CHr, iron parameters, and the intrinsic EPO concentration in non-dialysis CRF patients to clarify the alterations in CHr levels that occur as renal anemia progresses. CRF patients who visited our out-patient clinic (n = 189) were included in the study. Iron deficiency was defined by the transferrin saturation and ferritin levels. Conventional red blood cell parameters and CHr levels were measured using an ADVIA120 autoanalyzer (Bayer Medical, USA). The mean CHr value of the non-dialysis patients (creatinine clearance less than 70 ml/min) was 32.7 pg, which did not differ significantly from that of the dialysis patients. Significant correlations were found between CHr and TSAT (r = 0.032, p < 0.0177), unlike the correlation with intrinsic EPO levels. Overall, 11% of the patients were diagnosed as having iron deficiency. There was a positive correlation between CHr and serum creatinine levels. Non-dialysis CRF patients treated with rHuEPO at the dose of 24,000 U/month showed different CHr levels compared with other patients (less than 24,000 U/month). It is possible that rHuEPO treatment in non-dialysis patients affects iron dynamics. In conclusion, CHr is an easily measurable and reliable marker of iron status in non-dialysis CRF patients. Moreover, the CHr level was also sensitive to iron alternations in non-dialysis CRF patients under rHuEPO treatment. Accordingly, if long-acting EPO is available for non-dialysis CRF patients, the CHr value is likely to be indicative of the need for iron supplementation.
 ...
PMID:[Measuring the content of reticulocyte hemoglobin (CHr) in predialysis chronic renal failure (CRF) patients]. 1450 18

We report the case of a patient with a severe chronic radiation enteropathy. She had been dependent on red cell transfusions for many years. On admission, she displayed anemia (8.6 g/dL) resulting from both inadequate EPO production and a functional iron deficiency. A 3-wk IV iron sucrose treatment (200 mg once weekly) resulted in an increased reticulocyte count, but did not raise the hemoglobin (Hb) level. The adjunction of epoetin alpha (10,000 IU three times a week) made it possible to reach the normal range (12.9 g/dL) after a 17-wk treatment. As the anti-anemic treatment discontinued, the Hb level decreased to 11.1 g/dL within 2 wk. Giving EPO again (10,000 IU twice a week) failed to maintain the Hb level, which dropped under basal values (7.8 g/dL). In contrast, a second combination EPO/iron sucrose did restore a normal Hb level and maintained it. This case report supports the combination of EPO and IV iron supplementation in patients with anemia of chronic disease and either an impaired iron absorption or intolerance to oral iron.
 ...
PMID:Epoetin alfa and intravenous iron sucrose to treat severe anemia in a patient with chronic radiation enteropathy: a case report. 1451 81

Diagnosing disorders of iron metabolism the concentration of the iron storing protein ferritin reflects the body's iron reserves much better than does serum iron concentrations or transferring saturation. Merely in the event of acute phase reactions is the validity of the ferretin level compromised. This applies in particular to the redistribution of iron in anemia caused by inflammatory conditions or malignancies, as also, though less markedly, to functional iron deficiency in renal anemia. Here, an additional diagnostic work-up, in particular when EPO/iron therapy is applied. Iron overload should be recognized already in the latent state before organ damage occurs. Clinically and chemically confirmed iron overload that cannot be ascribed to hematological disease, iron replacement of transfusions, should prompt a molecular-biological analysis of hemochromatosis-associated genetic defects.
 ...
PMID:[Diagnosing disorders of iron metabolism. Begin with ferritin]. 1562 34

Anemia is common in acute critically ill patients. Although blood loss, either by trauma, surgery, phlebotomies or gastrointestinal bleeding, may play a role, the anemia in these patients bears many similarities to the anemia characteristic of chronic disease. Serum iron is low with a high concentration of ferritin and low-to-normal transferrin and serum transferrin receptor levels. Several mechanisms may be involved, with inflammation playing a crucial role. Although the exact nature of the inflammatory response and the role of various cytokines need further elucidation, it is known that inflammation blunts the responsiveness of the hormone erythropoietin and induces functional iron deficiency. Iron is trapped in cells of the mononuclear phagocytic system and its release is temporarily blocked. The bone marrow is still capable of incorporating iron and of responding to treatment with recombinant human erythropoietin (rh-EPO). The duration of the anemia is related to the persistence of the inflammation. Although the effects of anemia on morbidity and mortality in the critically ill are poorly defined, a restrictive transfusion policy, in which hemoglobin concentration is maintained between 7.0 and 9.0 g/dl, proves to be at least as effective as, if not superior to, a more liberal regimen. In individual situations, such as in cardiovascular and cancer patients, higher thresholds may be appropriate. The administration of rh-EPO is an alternative to reduce the need for red blood cell transfusions and to avoid transfusion-related complications. Although its efficacy has been shown, questions regarding cost-benefit, dose regimen and clinical outcomes need to be answered before its large-scale use can be recommended.
 ...
PMID:Anemia in critically ill patients. 1566 82


<< Previous 1 2 3 4 5 Next >>