Lipoic acid and Neuropathy
Lipoic acid decreases lipid peroxidation and protein
glycosylation and increases (Na(+) + K(+))- and
Ca(++)-ATPase activities in high glucose-treated human
erythrocytes.
Jain SK, Lim G. Free Radic Biol Med 2000;29:1122-1128.
Lipoic acid supplementation has been found to be
beneficial in preventing neurovascular abnormalities
in diabetic neuropathy. Insufficient (Na(+) +
K(+))-ATPase activity has been suggested as a
contributing factor in the development of diabetic
neuropathy. This study was undertaken to test the
hypothesis that lipoic acid reduces lipid peroxidation
and glycosylation and can increase the (Na(+) + K(+))-
and Ca(++)-ATPase activities in high glucose-exposed
red blood cells (RBC). Washed normal human RBC were
treated with normal (6 mM) and high glucose
concentrations (45 mM) with 0-0.2 mM lipoic acid
(mixture of S and R sterioisomers) in a shaking water
bath at 37 degrees C for 24 h. There was a significant
stimulation of glucose consumption by RBC in the
presence of lipoic acid both in normal and high
glucose-treated RBC. Lipoic acid significantly lowered
the level of glycated hemoglobin (GHb) and lipid
peroxidation in RBC exposed to high glucose
concentrations. High glucose treatment significantly
lowered the activities of (Na(+) + K(+))- and
Ca(++)-ATPases of RBC membranes. Lipoic acid addition
significantly blocked the reduction in activities of
(Na(+) + K(+))- and Ca(++)-ATPases in high glucose-
treated RBC. There were no differences in lipid
peroxidation, GHb and (Na(+) + K(+))- and
Ca(++)-ATPase activity levels in normal
glucose-treated RBC with and without lipoic acid.
Thus, lipoic acid can lower lipid peroxidation and
protein glycosylation, and increase (Na(+) + K(+))-
and Ca(++)-ATPase activities in high-glucose exposed
RBC, which provides a potential mechanism by which
lipoic acid may delay or inhibit the development of
neuropathy in diabetes.
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