Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Heme proteins transport oxygen and facilitate redox reactions. Heme, however, may be dangerous, especially when free in biologic systems. For example, iron released from hemoglobin-derived heme can catalyze oxidative injury to neuronal cell membranes and may be a factor in post-traumatic damage to the central nervous system. We have shown that heme catalyzes the oxidation of low density lipoproteins which can damage vascular endothelial cells. The endothelium is susceptible to damage by oxidants generated by activated phagocytes, and this has been invoked as an important mechanism in a number of pathologies including the Adulte Respiratory Distress Syndrome (ARDS), acute tubular necrosis, reperfusion injury and atherosclerosis. Because of its highly hydrophobic nature, heme readily intercalates into endothelial membranes and potentiates oxidant-mediated damage. This injury is dependent on the iron content of heme and is completely blocked when concomitant hemopexin is added. Ferrohemoglobin, when added to cultured endothelial cells, is without deleterious effects, but if oxidized to ferrihemoglobin (methemoglobin), it greatly amplifies oxidant damage. Methemoglobin, but not ferrohemoglobin, releases its hemes which can then be incorporated into endothelial cells. Cultured endothelial cells, when exposed to methemoglobin but not ferrohemoglobin, cytochrome c or metmyoglobin, potentiate this oxidant injury. Stabilization of the methemoglobin by cyanide, haptoglobin or capture of the heme by hemopexin abrogates this effect. Paradoxically, more prolonged exposure of endothelium to heme or methemoglobin renders them remarkably resistant to oxidant challenge. Endothelium defends itself from heme by induction of the heme degrading enzyme heme oxygenase and the concomitant production of large amounts of the iron binding protein ferritin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Heme and the vasculature: an oxidative hazard that induces antioxidant defenses in the endothelium. 808 43

Chronic lung disease (CLD) is a major cause of long term morbidity in preterm infants. Reactive oxygen species (ROS) play an important role in the pathogenesis of CLD. We show that a high percentage (63 to 83%) of the investigated bronchoalveolar secretions (BAS) of neonates contain bleomycin-detectable free iron concentrations (0. 04-0.124 nmol/micrograms SC, median range). Beside the presence of redox-active iron several iron-binding proteins like transferrin, ferritin and lactoferrin were determined in BAS. Comparison of protein distribution within the first three days of life showed slight differences between the group of preterm infants who developed CLD and the neonates who recovered from RDS. Because of the existence of free iron we suggest a higher risk of hydroxyl radical formation in the alveolar space. In an artificial system with addition of iron and hydrogen peroxide we were able to demonstrate OH-radical production in BAS by electron paramagnetic resonance (EPR). OH-radical formation by H2O2 and iron in buffer solution was slightly enhanced in the presence of BAS, indicating the absence of OH-radical-scavengers in BAS.
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PMID:Presence of bleomycin-detectable free iron in the alveolar system of preterm infants. 1009 36