Hematopoietic Growth Factors Flashcards
nutritional growth factors
ferrous iron (Fe2+)
folic acid
hydroxocobalamin (B12)
hormonal growth factors
Epoetin alpha; Darbepoetin
G-CSF
GM-CSF
what does erythropoiesis require
nutrients (iron, folic acid, vit B12) and growth factors (G-CSF, GM-CSF, Epoetin)
what is iron needed to make
hemoglobin
each of the four heme groups has a central iron
source of iron
dietary- meat
non-heme iron in foods like veggies must be reduced to ferrous iron for absorption
form of body absorbable iron
ferrous iron (Fe2+)
what increases absorption of iron
vit C and HCL
what is the storage form of iron
ferritin
what is the transport form of iron
transferrin
how is iron eliminated
no excretion mechanisms
regulation of iron balance is achieved by changing absorption and storage of iron
when body iron stores are high: iron stored as ferritin
when body iron stores are low: iron transported to bone marrow for hemoglobin production
role of apoferritin
if free iron is low, synthesis is inhibited and iron binding shifts to transferrin
if free iron is high, synthesis stimulated and iron is sequestered as ferritin to protect organs from iron’s toxic effects
treatment of acute iron toxicity
Deferoxamine
treatment of chronic iron toxicity AKA iron overload AKA hemochromatosis
phlebotomy or chelation therapy
chelators: Deferoxamine or Deferasirox
adverse affects of iron salts AKA oral iron supplements
epigastric distress
abdominal cramps
etc
what is used if patient can’t tolerate/absorbe oral iron supplements
stable complex of ferric hydroxide and low molecular weight dextran given via muscular infection or IV infusion
other preps=sodium ferric gluconate, iron sucrose-less likely to produce anaphylaxis
iron balance is predominantly regulated by
absorption from diet
what does deficiency of vit B12 or folic acid lead to
megaloblastic anemia
vit B12 and folic acid deficiency has lots of the same effects but what additional thing does vit B12 deficiency lead to
neurologic syndorme because degeneration of myelin sheath
what is dietary folate dependent on
dietary use of folate is dependent on B12
so if B12 deficient there is a functional deficiency of dietary folate
where is vit B12 stored and how long are stores
liver
5 years to deplete
what population can you see vit B12 deficiency
strick vegetarians
what is vitamin B12 dependent on
intrinsic factor (pernicious anemia)
because supplemental folic acid enters the pathway at a different place than dietary folate, large amounts of folic acid can correct the anemia due to vit B12 but what can it not correct
cannot correct the neurologic damage
partial removal of which part of the GI tract could result in B12 deficiency
Illium
but also stomach due to intrinsic factor
how soon can anemia develop with deficiency of folic acid
1-6 months
what erythrocyte precursors are effected by EPO (Epoetin alpha) response
BFU-E
CFU-E
pro erythroblast
basophilic erythroblast
where is epoetin alpha made
kidneys (senses tissue hypoxia)
what does epoetin alpha do
induces release of reticulocytes from marrow
indications of epoetin alpha and anemia
anemia due to chronic renal failure
anemia due to AZT in HIV patients (HIV patients are being treated with AZT which dec EPO)
what is a better drug to use than epoetin alpha when patient has chronic renal failure
Darbepoetin alpha cuz clearance is slowed because longer half life
G-CSF
stimulates progenitor cells already committed to neutrophil lineage
mobilizes stem cells of all lineages into peripheral blood stem cells for easy collection for autologous stem cell transplantation
GM-CSF
stimulates proliferation and differentiation of granulocytic progenitor cells as well as erythroid and megakaryocytic progenitors
