The clinical relevance of detectable plasma iron species in iron overload states and subsequent to intravenous iron-carbohydrate administration.

Many disorders of iron homeostasis (e.g., iron overload) are associated with the dynamic kinetic profiles of multiple non-transferrin bound iron (NTBI) species, chronic exposure to which is associated with deleterious end-organ effects.

Vaccine efficacy and iron deficiency: an intertwined pair?

Vaccines are the most effective measure to prevent deaths and illness from infectious diseases. Nevertheless, the efficacy of several paediatric vaccines is lower in low-income and middle-income countries (LMICs), where mortality from vaccine-preventable infections remains high. Vaccine efficacy can also be decreased in adults in the context of some common comorbidities.

Autoimmune gastritis.

Autoimmune gastritis (AIG) is an increasingly prevalent, organ-specific, immune-mediated disorder characterized by the destruction of gastric parietal cells, leading to the loss of intrinsic factor and reduced acid output. These alterations result in malabsorption of iron, vitamin B (pernicious anaemia) and potentially other micronutrients. For several years, most studies have focused on pernicious anaemia only, generating confusion between the two entities.

How I treat unexplained refractory iron deficiency anemia.

Endoscopic gastrointestinal workup fails to establish the cause of iron deficiency anemia (IDA) in a substantial proportion of patients. In patients referred for hematologic evaluation with unexplained or refractory IDA, screening for celiac disease, autoimmune gastritis, Helicobacter pylori, and hereditary forms of IDA is recommended. About 4% to 6% of patients with obscure refractory IDA have celiac disease, and autoimmune gastritis is encountered in 20% to 27% of patients.

Pathogenesis and management of iron toxicity in thalassemia.

In thalassemia major, iron overload is the joint outcome of multiple blood transfusions and an inappropriately increased iron absorption associated with ineffective erythropoiesis. Threshold values for iron toxicity are a liver iron concentration exceeding 440 mmoles/g dry weight, serum ferritin >2500 ng/mL, DFO urinary iron excretion >20 mg/day, and transferrin saturation >75%. The outpouring of catabolic iron that exceeds the iron-carrying capacity of transferrin results in the emergence of non-transferrin-bound iron (NTBI).

Iron deficiency, Helicobacter infection and gastritis.

Despite elegant regulatory mechanisms, iron deficiency anemia (IDA) remains one of the most common nutritional deficiencies of mankind. Iron deficiency is the result of an interplay between increased host requirements, limited external supply, and increased blood loss. When related to increased physiologic needs associated with normal development, iron deficiency is designated physiologic or nutritional.

Pathogenesis and management of iron deficiency anemia: emerging role of celiac disease, helicobacter pylori, and autoimmune gastritis.

The causes of iron deficiency vary significantly during different stages of life, and according to gender and socioeconomic circumstances. Although dietary iron is important, iron deficiency anemia (IDA) is mostly attributed to blood loss and may be the presenting clinical feature of occult bleeding from the gastrointestinal (GI) tract heralding underlying malignancy. Conventional GI diagnostic workup fails to establish the cause of iron deficiency in about one third of patients.

Iron overload in thalassaemia intermedia: reassessment of iron chelation strategies.

Thalassaemia intermedia (TI) is a syndrome marked by its diverse underlying genetic basis although its pathophysiology remains unclear, particularly regarding the nature of iron loading and toxicity. It is, however, evident that there are key differences from the extensively studied thalassaemia major (TM) population and caution is required when assessing iron load based on serum ferritin values, as this approach is known to underestimate the true extent of iron loading in patients with TI. Although effective iron chelation therapy has been available for many years, studies in TI-specific populations are rare and evidence suggests that management of iron levels may be less rigorous than in patients with TM and other chronic anaemias.

Iron overload in Asia.

In a remarkable study in this issue of Blood, Lok and colleagues describe the genotypic and phenotypic characteristics of hereditary hemochromatosis in 42 cases in 8 distinct families of Asian origin.

High nontransferrin bound iron levels and heart disease in thalassemia major.

Although the presence of nontransferrin bound plasma iron (NTBI) in transfusional iron overload is well documented, knowledge about its clinical significance is limited. We assessed NTBI levels in a large and homogeneous series of thalassemia patients on regular transfusion and chelation and explored the hypothesis that NTBI levels may be associated with relevant clinical outcomes: in particular, heart disease. Among 174 patients with thalassemia major and intermedia, we showed the presence NTBI in 145 of 174 or 83.

Mechanism of iron toxicity.

The subtle balance between proinflammatory and antiinflammatory cytokines plays an important role in determining the severity of the inflammatory reaction and in the anomalous iron handling associated with infection. Conversely, iron deficiency per se appears to limit the severity of the inflammatory response. All of these considerations are at present highly speculative and in need of further experimental and epidemiologic support.

Iron loading and its clinical implications.

The main aspects of iron loading and the consequent clinical implications described in this series of articles are summarized in this final chapter. Despite mechanisms to maintain iron homeostasis, harmful iron accumulation can occur in patients with hereditary defects of regulatory proteins, such as hepcidin, or with transfusion-dependent anemias, such as thalassemia and myelodysplastic syndromes. Identifying the role of nontransferrin bound iron in the pathogenesis of disease allows for better treatment strategies to prevent and reverse iron toxicity.

The anemia of achylia gastrica revisited.

Autoimmune atrophic gastritis is encountered in 20-27% of patients with obscure, or refractory iron deficiency anemia and is 4 to 6 times more common than celiac disease causing unexplained iron deficiency. The unique clinical features of iron deficiency anemia associated with achlorhydria and mucosal atrophy sparing the gastric antrum have all been accurately described by Faber and others over 100 years ago, including its refractoriness to oral iron treatment, female predominance, relatively young age, increased prevalence of thyroid disease and tendency to progress to pernicious anemia. A significant new development is the relation between autoimmune gastritis and Helicobacter pylori infection.

Decreased treatment failure rates following duodenal release ferrous glycine sulfate in iron deficiency anemia associated with autoimmune gastritis and Helicobacter pylori gastritis.

Background And Objectives: Since gastric acidity and ascorbate play a critical role in the solubilization and reduction of iron for subsequent absorption, the achlorhydria associated with autoimmune and Helicobacter pylori gastritis may explain the poor response of such patients to oral iron treatment. In order to circumvent this problem, we explored the therapeutic potential of a duodenal formulation of ferrous glycine sulfate consisting of micropellets that do not dissolve at the acid environment of the stomach but, owing to their solubility at a higher pH, discharge their content directly into the duodenum.

Design And Methods: In a case-control study, the treatment results of 39 patients with iron deficiency anemia receiving a duodenal formulation of ferrous glycine sulfate (group A) were compared with the results of 39 patients receiving other oral iron compounds (group B).

A hematologist's view of unexplained iron deficiency anemia in males: impact of Helicobacter pylori eradication.

Background And Objectives: Helicobacter pylori infection with, or without coexisting autoimmune gastritis has been implicated in several recent studies as an important cause of IDA in patients with unexplained iron deficiency anemia (IDA). However, the role of H. pylori in the causation of IDA is still unsettled as the vast majority of reported patients were premenopausal women in whom menstrual blood loss was likely the dominant factor determining IDA.

Action of chelators in iron-loaded cardiac cells: Accessibility to intracellular labile iron and functional consequences.

Labile iron in hemosiderotic plasma and tissue are sources of iron toxicity. We compared the iron chelators deferoxamine, deferiprone, and deferasirox as scavengers of labile iron in plasma and cardiomyocytes at therapeutic concentrations. This comprised chelation of labile plasma iron (LPI) in samples from thalassemia patients; extraction of total cellular iron; accessing labile iron accumulated in organelles and preventing formation of reactive-oxidant species; and restoring impaired cardiac contractility.

Objectives and mechanism of iron chelation therapy.

Prevention of cardiac mortality is the most important beneficial effect of iron chelation therapy. Unfortunately, compliance with the rigorous requirements of daily subcutaneous deferoxamine (DFO) infusions is still a serious limiting factor in treatment success. The development of orally effective iron chelators such as deferiprone and ICL670 is intended to improve compliance.

Variable hematologic presentation of autoimmune gastritis: age-related progression from iron deficiency to cobalamin depletion.

Iron deficiency is a known complication of achlorhydria and may precede the development of pernicious anemia. Among 160 patients with autoimmune gastritis identified by hypergastrinemia and strongly positive antiparietal antibodies, we explored the overlap between 83 subjects presenting with iron deficiency anemia (IDA), 48 with normocytic indices, and 29 with macrocytic anemia. Compared with macrocytic patients, patients with IDA were 21 years younger (41 +/- 15 years versus 62 +/- 15 years) and mostly women.