Iron Flashcards
transferrin
protein that transports oxidized iron (Fe3+) through blood to tissues
ferritin
iron (Fe2+) storage molecule within cells
where in GI is iron primarily absorbed?
duodenum
is iron ingested in oxidized or reduced form?
oxidized form (Fe3+). must be reduced to Fe2+ via Reductase enzyme on intestinal epithelium before absorption
transport protein for iron into intestinal epithelia?
DMT1 (reduced form Fe2+)
transport protein for iron out of intestinal epithelial into blood stream
Ferroportin (FPN1). transports (Fe2+), oxidase enzyme oxidizes the molecule to Fe3+ before it is bound to transferrin
where does process of iron recycling begin?
within macrophages
major source of iron for erythropoeisis
recycling
iron exporter out of macrophages?
ferroportin
iron regulatory hormone produced in liver
hepcidin
what type of regulator is hepcidin?
negative regulator
functions of hepcidin
inhibits intestinal iron absorption and macrophage release of iron
stimuli that decrease hepcidin levels
iron deficiency, increased erythroid demand, hypoxia (all times when we need more iron)
stimuli that increase hepcidin levels
iron overload, inflammation
mechanism of hepcidin
binds to and down regulates ferroportin, thereby inhibiting iron release from macrophages or intestinal epithelia
causes of iron deficiency
inadequate supply (nutritional & malabsorption) or increased demand (blood loss, rapid growth, pregnancy)
what can help increase the absorption of iron?
eating heme iron from meat and intake of vitamin C (enhances absorption somehow)
signs & symptoms of iron deficiency
pallor, weakness, fatigue, headache, irritability, pica, koionychia, angular stomatitis, blue sclerae
koilonychia
spoon finger nails
angular stomatitis
inflammation of corner of lips
hematologic markers of iron deficiency
decreased Hb, RBC, MCV, reticulocyte count
increased RDW, platelets
biochemical markers of iron deficiency
decreased ferritin, serum Fe, transferrin saturation
increased TIBC, FEP
TIBC
total iron binding capacity. increased values indicate greater number of open iron binding sites on transferrin
treatment for iron deficiency
correct the deficiency via oral ferrous sulfate/slow release iron/parenteral iron/red cell transfusion. then correct the underlying cause
characteristics of anemia from chronic inflammation
mild/moderate anemia, normo/microcytic, normal/low reticulocytes. decreased serum Fe, normal iron stores, increased serum ferritin (weird mix of iron deficient and replete symptoms)
general characteristic of anemia from chronic inflammation
abnormal systemic iron distribution.
what is most likely cause of anemia from chronic inflammation
hepcidin excess due to inflammatory cytokine stimulation
best test to distinguish iron deficiency anemia from anemia of chronic inflammation?
serum ferritin levels (high in ACI, low in IDA)
