Vitamin E Flashcards
family + what is for humans?
a, b, gamma, sigma tocopherol
a, b, gamma, sigma tocotrienol
a tocopherol for humans. based on AVED
mutation on alpha TTP production. this protein ONLY binds to a tocopherol for transport
3 types
natural: a tocopherol
synthetic: all rac tocopherol (4/8 maintained in humans)
natural source (veg oils): synthesized by methylation of gamma tocopherol
Absorption
20-40% absorbed. transported via VLDL in plasma
Storage
adipose, liver, muscle as free in cell membranes
excreted as VE metabolites, CEHC derivatives
Function
Antioxidant. major membrane bound, lipid antioxidant. peroxyl radical trapping, chain breaking.
Lipid Peroxidation – Initiation
R radical produced by attack on species capable of extraacting H from USFA
Lipid Peroxidation – Propagation
R + O2 –> R-OO , FA peroxyl radical formed
R-OO + RH –> R-OO-H + R, chain reaction, membrane destabilization
Lipid Peroxidation – Termination
R-OO + a-TH –> R-OO-H + aT
end: ethane, pentane, MDA
regeneration of oxidized vitamin E by glutathione, vit C
Deficiency
fat malabsorption: kids w cholestatic liver disease, cystic fibrosis, bowel resection, crohn’s, celiac disease, TPN treatment.
treatment: RRR- aT, TPGS (H2O soluble), viprimol (IM)
AVED
ataxia w vitamin E deficiency
ataxia, dysarthria, muscle weakness, paresthesia
low aT conc in blood
ABL
abetalipoprotenemia, no Apo B (CM, LDL, VLDL)
fat malabsorption, acanthocytosis, hypocholesterolemia, atypical retinotis pigmentosa, coagulopathy, peripheral neuropathy
treatment: fat soluble vitamins, vit E
Supplements?
for CVD –> lower oxidation of LDL in vitro
and for ABL, AVED
HOPE, HOPE TOO
Doesnt work because when vit E is administered over long periods, it may act as a pro oxidant, forming harmful radicals in myocardium that may adversely affect excitation- contraction coupling, leading to a reduction in L ventricular function
