Blogging with Parkinson's

A personal perspective on Young Onset Parkinson's

Oxidative stress may not be to blame

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Yellow light signals emitted by the biosensor indicate oxidant production in the tissue of a migrating fly larva. Source: Tobias Dick, German Cancer Research Center

The antioxidant myth is a persistent one, and one that I have touched upon before. It has been suggested that excess oxidants may be a cause of Parkinson’s, as they are reputed to make cells die quicker. However, recently reported research from Germany knocks another nail into the coffin of the myth: it reveals how oxidative stress affects fruit flies.

Scientists at the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) added genes for special biosensors into the genetic material of the flies. The biosensors emit a light signal to indicate “the oxidative status of each cell […] in realtime, in the whole organism and across the entire life span.”

An article published by the research centre says:

Up to now, many scientists have assumed that the aging process is associated with a general increase in oxidants throughout the body. However, this was not confirmed by the observations made by the investigators across the entire life span of the adult animals. They were surprised that almost the only age-dependent increase in oxidants was found in the fly’s intestine. Moreover, when comparing flies with different life spans, they found out that the accumulation of oxidants in intestinal tissue even accelerated with a longer life span. The group thus found no evidence supporting the frequently voiced assumption that an organism’s life span is limited by the production of harmful oxidants. [My emphasis.]

“Oxidative stress: Less harmful than suspected?”
No. 65 | 05/12/2011 | by Koh

The scientists, led by Associate Professor (PD) Dr. Tobias Dick of DKFZ, fed the flies with N-acetyl cysteine (NAC), “a substance which is attributed an antioxidant effect and which some scientists consider suitable for protecting the body against presumably dangerous oxidants.”

Interestingly, no evidence of a decrease in oxidants was found in the NAC-fed flies. On the contrary, the researchers were surprised to find that NAC prompted the energy plants of various tissues to significantly increase oxidant production.

“Many things we observed in the flies with the help of the biosensors came as a surprise to us. It seems that many findings obtained in isolated cells cannot simply be transferred to the situation in a living organism,” said Tobias Dick, summarizing their findings. “The example of NAC also shows that we are currently not able to predictably influence oxidative processes in a living organism by pharmacology,” he adds. “Of course, we cannot simply transfer these findings from fly to man. Our next goal is to use the biosensors to observe oxidative processes in mammals, especially in inflammatory reactions and in the development of tumors.”

There’s a long way to go, but this is a significant step – from previous experiments that looked at isolated cells under lab conditions, to a functioning organism. It certainly seems, from this, that the influence of oxidants on the onset and progression of a condition such as Parkinson’s is unlikely to be significant.

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