Boosting Repair Mechanisms Beneficial in Alzheimer's
July 03 2009   |   Permanent Link
One might expect that improving repair and maintenance systems in the brain would provide some benefit irrespective of how present damage came about, and this may be the case: "The granulocyte-colony stimulating factor (GCSF) significantly reduced levels of the brain-clogging protein beta amyloid deposited in excess in the brains of the Alzheimer's mice ... The growth factor prodded bone-marrow derived microglia outside the brain to join forces with the brain's already-activated microglia in eliminating the Alzheimer's protein from the brain. Microglia are brain cells that act as the central nervous system's main form of immune defense. Like molecular 'Pac-men,' they rush to the defense of damaged or inflamed areas to gobble up toxic substances." This is still a rearguard action against end-stage consequences, however - the underlying chain of causes is not addressed. Repair of final consequences isn't a viable long-term strategy for dealing with an ever-worsening root cause, as those consequences will rapidly exceed the ability to repair them. At some point you have to address the origin of the problem in order to prevent it from spiraling out of control.

Immune Therapy Versus Leukemia Stem Cells
July 03 2009   |   Permanent Link
Via EurekAlert!, an example of progress in using the immune system to target specific cells for destruction: acute myeloid leukemia (AML) "is a cancer of the white blood cells that has an extremely poor prognosis and does not respond well to conventional chemotherapy. ... The cellular and molecular basis for this dismal picture is unclear. However, previous research has suggested that leukemia stem cells (LSCs) may lie at the heart of post-treatment relapse and chemoresistance ... [researchers] exploited the fact that the molecule CD123 is expressed at very high levels on LSCs but not on normal blood cells. CD123 is part of the interleukin-3 receptor, a protein that interacts with a growth factor (called a cytokine) that influences cell survival and proliferation. The researchers created a therapeutic antibody that recognized and bound to CD123 with the hope that this antibody would selectively interfere with AML-LSC survival. When AML-LSCs from human patients were transplanted into mice treated with the antibody, called 7G3, cytokine signaling in the tumor cells was blocked. Further, 7G3 impaired migration of the AML-LSCs to bone marrow and activated the innate immune system of the host mouse to destroy the AML-LSCs. Overall, treatment with 7G3 substantially improved mouse survival."

Collecting Cellular Junk
July 02 2009   |   Permanent Link
Newer longevity science blog Green Light Go here looks at the harmful accumulation of metabolic byproducts and other junk such as lipofuscin in our cells with age: "I just finished an entry for the SOA timeline on the 1970s discovery that nematodes collect inactive enzymes and molecules as they grow older. The main idea being that the body is unable to clear out the junk inside cells and that the energy cost of carrying this junk leads to senescence, or aging. The theory reminded me of a similar finding by Coleen Murphy who found that long lived daf-16 elegans mutants lived longer in part because they encoded antimicrobial lysosomes, that helped to clear out microbes that would get "packed" inside the nematodes precipiating senescence and eventually their death. As far as I know, the reason for the slow decline in enzyme activity and for the collection of intracellular junk is still unknown. Why isn't our body clearing this stuff out and selling it on ebay? The SENS foundation, which is perhaps the biggest player in anti-aging research, is pushing forward with a solution anyway. Their strategy is to find enzymes manufactured by soil bacteria and fungi that can then be applied therapeutically to help clear junk out of cells. ... It is going to be interesting in the future to see what result comes of this. Both for understanding the chemical mechanism of the collection of junk, and the therapeutic solutions which can get rid of it."

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