|LE Magazine April 2002|
Growing evidence for memantine treatment of Alzheimer's related dementia
Memantine is slowly gaining ground as a potential treatment for Alzheimer’s disease. Life Extension reported on the merits of this novel compound back in July 2001, and has been recommending it for use for much longer still. In Germany, memantine has been available for over 10 years and is the most frequently prescribed treatment for dementia, but it hasn’t been approved in North America.
New findings from two studies presented at a major neuropsychopharmacology conference (Hawaii, December 2001) suggest that memantine presents a unique, safe and effective way to treat dementia. Researchers at New York University conducted a six-month open-label extension study evaluating memantine’s long-term benefits in 175 patients with advanced Alzheimer’s disease. One-year results showed that memantine improved cognition, daily functioning and behavior, while slowing down mental decline in previously untreated patients. Likewise, a team of Spanish and German scientists found that, in rat brains injected with beta-amyloid, memantine significantly reduced the amount of neuronal degeneration and improved behavioral and functional measures.
Other researchers have also reported positive findings about memantine for dementia. For example, a US study [Le DA, et al. Drugs Aging 2001;18(10):717-24] suggested that memantine is clinically safer than many other NMDA antagonists in treating neurodegenerative diseases. And Swedish researchers at the Karolinska Institute [Winblad B, et al. Int J Geriatr Psychiatry 1999 Feb;14(2):135-46] concluded that memantine treatment may lead to functional improvement and reduces care dependence in severely demented patients. It’s believed that memantine’s neuroprotective effects are due to blocking the NMDA receptor against excitotoxicity (overstimulation of glutamate) without upsetting the neurotransmitter’s normal functioning as some other drugs do.
Aged garlic lowers oxidative stress in humans
A study published in the February 2002 issue of The Journal of Nutrition showed that dietary supplementation with aged garlic lowered a marker of oxidative stress in human volunteers. The study examined the effects of Kyolic brand aged garlic on 20 healthy men and women, divided into two groups consisting of smokers and nonsmokers. Data concerning age, height, weight, alcohol consumption and number of cigarettes smoked daily was obtained from each participant, and blood and urine samples were taken.
Study participants were given five milliliters (1.525 grams of extracted solids) of aged garlic extract once daily for 14 days. No lifestyle changes were requested of the volunteers. After 14 days and 28 days, blood and urine samples were recollected. Urine and plasma levels of free 8-iso-prostaglandin F2-alpha, a measure of lipid peroxidation, were determined.
At the study’s onset, blood plasma concentrations of 8-iso-PGF2-alpha in smokers were 58% higher than that of age and sex-matched nonsmokers, and 85% higher in the urine. After 14 days of aged garlic supplementation, the nonsmokers experienced a 29% drop in the plasma concentration of the oxidative stress marker while smokers experienced a 35% drop. Urinary concentrations fell by 37% in the nonsmoking group and 48% in smokers. When levels were remeasured two weeks following the last dose of aged garlic, they were found to have returned to those measured at the study’s onset, before supplementation was initiated.
A discussion of the results noted the confirmation of the increased oxidative stress observed in smokers compared to nonsmokers, and the authors conclude that dietary supplementation with aged garlic may help prevent diseases associated with oxidative stress, such as atherosclerosis.
Mechanism of action found for
vitamin C against cancer
A letter published in the January 12, 2002 issue of The Lancet suggests an explanation for the benefit of vitamin C against cancer. Researchers from Cornell University and Seoul National University in Korea discovered that the vitamin inhibits the cancer-causing effects of hydrogen peroxide on communication between cells. They also found that the phytochemical quercetin, which exists in apples and other plant foods, has an even stronger effect than vitamin C.
Study coauthor Professor C Y Lee of Cornell explained, “Vitamin C has been considered one of the most important essential nutrients in our diet since the discovery in 1907 that it prevents scurvy. In addition, vitamin C has several important functions in our body for the synthesis of amino acids and collagen, wound healing, metabolism of iron, lipids and cholesterol and others. In particular, vitamin C is a well known antioxidant that scavenges free radicals. Vitamin C prevents the inhibition of gap-junction intercellular communication (GJIC) induced by hydrogen peroxide.”
Gap junction intercellular communication is necessary for the maintenance of normal cell growth and differentiation, and when inhibited, is associated with cancer promotion. Hydrogen peroxide, which is known to promote tumor growth, inhibits GJIC by modification of a protein. The researchers pretreated rat liver epithelial cells with vitamin C and found that hydrogen peroxide was unable to exert this inhibitory effect, while other antioxidants tested failed to prevent it. This suggests that vitamin C’s mechanism of action in tumor inhibition is other than that of a free radical scavenger, and that prevention of CJIC is more likely. They conclude, “A diet rich in phytochemicals and vitamin C will reduce the risk of cancer.”
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