Modulatory effects of vitamin E, acetyl-L-carnitine and α-lipoic acid on new potential biomarkers for Alzheimer's disease in rat model.

Alzheimer's disease (AD) is the most common chronic neurodegenerative disorder associated with aging. This study aimed to explore new markers for AD as total homocysteine (tHcy), insulin, insulin like growth factor-1 (IGF-1), interlukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α); to determine the modulatory effects of vitamin E (VE), acetyl-L-carnitine (ALC) and α-lipoic acid (LA) on the investigated parameters and to evaluate the possible therapeutic role of these nutraceutical in AD-induced in rats. Our results revealed that brain acetylcholine esterase (AChE) activity and tHcy levels were significantly increased in AD model. Folic acid, vitamin B(12) levels and Na(+)/K(+) ATPase activity were markedly reduced. Plasma insulin and IGF-1 levels were noticeably decreased but plasma TNF-α and IL-1β concentrations were significantly increased, confirming that abnormal inflammatory response is associated with AD. Treatment by VE, ALC and LA restored the above mentioned parameters to about normal levels comparable to those of donepezil, indicating that tHcy, insulin, IGF-1, IL-1β and TNF-α may be considered as new biomarkers for AD. The study points to the potential restoring effects of VE, ALC and LA in AD model. Our study provides evidence for the importance of dietary supplementation in delaying the progression of age-related neurodegenerative diseases.