Re: lipofuscin (was) Green Tea Extract

[Guest guest]

In a message dated 9/22/04 5:33:14 PM Eastern Daylight Time, mambomambo@... writes:

On the other hand one of the benefits of green tea is its ability to absorb

iron in those people who build it up as excess iron is thought to be a major

cause of free radical damage.

I also understand that rice bran will chelate excess iron, and the responsible component is IP6. (This might be especially useful for people with liver conditions such as hepatitis.)

As a chelator of excess iron, it might help reduce lipofuscin: "Lipofuscin, thus, may be much more directly related to cellular degeneration at old age than was hitherto believed"

Free Radic Biol Med. 2002 Sep 1;33(5):611-9.

Lipofuscin: mechanisms of age-related accumulation and influence on cell function.

PMID: 12208347

http://tinyurl.com/466uu

The accumulation of lipofuscin within postmitotic cells is a recognized hallmark of aging occurring with a rate inversely related to longevity. Lipofuscin is an intralysosomal, polymeric substance, primarily composed of cross-linked protein residues, formed due to iron-catalyzed oxidative processes. Because it is undegradable and cannot be removed via exocytosis, lipofuscin accumulation in postmitotic cells is inevitable, whereas proliferative cells efficiently dilute it during division. The rate of lipofuscin formation can be experimentally manipulated. In cell culture models, oxidative stress (e.g., exposure to 40% ambient oxygen or low molecular weight iron) promotes lipofuscin accumulation, whereas growth at 8% oxygen and treatment with antioxidants or iron-chelators diminish it. Lipofuscin is a fluorochrome and may sensitize lysosomes to visible light, a process potentially important for the pathogenesis of age-related macular degeneration. Lipofuscin-associated iron sensitizes lysosomes to oxidative stress, jeopardizing lysosomal stability and causing apoptosis due to release of lysosomal contents. Lipofuscin accumulation may also diminish autophagocytotic capacity by acting as a sink for newly produced lysosomal enzymes and, therefore, interfere with recycling of cellular components. Lipofuscin, thus, may be much more directly related to cellular degeneration at old age than was hitherto believed.

--

Ken