11 Iron and GI disease Flashcards
How might iron be lost?
bleeding (menstruation)
tumours use it
stool (men)
What sort of structure is haem?
porphyrin ring
Where can iron be stored?
in the liver, yay!
What form is iron in veg?
ferric - Fe3+
What transporter puts iron into circulation?
Ferroportin
What absorbs iron, stopping it from damaging the cell?
ferritin
In what form must pure iron be absorbed by enterocytes, what achieves this?
Fe2+
Fe3+ -> Fe2+ by ferric reductase
What enterocyte transporter absorbs Fe2+?
DMT1
What enterocyte transporter absorbs haem associated iron?
HCP1
What binds to iron in the blood?
transferrin
How might haem be broken down in cells?
into billiverdin, which releases the iron, and then billirubin
What signals the small bowel to increase iron uptake?
Hepcidin secretion by the liver
How does hepcidin increase cellular iron levels?
binds ferroportin stopping iron efflux
What effect does hypoxia, and hence erythropoiesis have on hepcidin levels… think!
decreases it, as we want more iron for the blood
What effect does infection and inflammation have on hepcidin levels, what is the problem here?
increases it, through interleukin 6
causes anaemia of chronic disease
What 2 main cell types does hepcidin work on?
macrophage and enterocytes
in inflammation, how can we limit further inflammation?
restricting iron levels, but this causes anaemia of chronic disease
What detects high iron levels?
TIR2 and HPE
How might you distinguish between anaemia of chronic disease and iron defficient anaemia?
measure hepcidin levels, in iron defficient anaemia we will have low hepcidin levels
What is he condition where we can’t make hepcidin, how is it treated?
hereditary haemochromatosis, treated with phlebotomy
What other disease might cause IDA, what is this disease?
Coeliac disease, autoimmune reaction to gliagin
