Diabetes accelerates the aging process and leads to
complications that include blindness, renal failure, nerve damage,
stroke, and cardiovascular disease. It has been hypothesized that high
plasma glucose concentrations are responsible for increased
mitochondrial free radical production and subsequent inactivation of
glyceraldehyde phosphate dehydrogenase (GAPDH) in vascular endothelial
cells and other cells implicated in these complications. As a
result of the decreased ability of GAPDH to process upstream
metabolites, three pathways of metabolic damage are activated, which
include the advanced glycation end-product formation pathway, the
protein kinase C pathway, and the hexosamine pathway. All three pathways
have been implicated in abnormal cell signaling in diabetes. A
group of German and U.S. scientists has now found that treating diabetic
rats with high doses of benfotiamine, a
lipid-soluble form of vitamin B1, can prevent diabetic retinopathy and
all three forms of metabolic damage by stimulating transketolase
activity and thus diverting excess metabolites toward the pentose
pathway. Although vitamin B1 is available over the counter, the
researchers at this time do not advocate self-treatment without further
clinical data.