Study identifies compound to work with antioxidant against toxic stresses

A new study has offered some insights into why the health of animals declines with age, and pointed to a compound that might help prevent some of the toxic processes involved.

In the study published in the journal Redox Biology, researchers at Oregon State University (OSU) tried to identify the resistance to toxins of young cells, compared to those of older cells, by using a toxic compound called menadione to stress the cells.

In the face of the stress, the young rat cells never decreased to less than 35 percent of its initial level of glutathione, an antioxidant known to help resist the toxic stresses of everyday life, whereas older rat cells' glutathione levels plummeted to 10 percent of their original level.

"We've known for some time of the importance of glutathione as a strong antioxidant," said Tory Hagen, lead author on the research and the Helen P. Rumbel Professor for Health Aging Research in the Linus Pauling Institute at OSU. "What this study pointed out was the way that cells from younger animals are far more resistant to stress than those from older animals."

To help boost the levels of the antioxidant, the researchers highlighted a compound, N-acetyl-cysteine, or NAC, which is already used in high doses in medical emergencies to help patients in a toxic crisis, such as ingestion of poisonous levels of heavy metals.

NAC, the researchers said, is known to boost the metabolic function of glutathione and increase its rate of synthesis. As it is believed to be a safe compound to use even at extremely high levels, the researchers are hypothesizing that it might have significant value at much lower doses to maintain glutathione levels and improve health.

"Using NAC as a prophylactic, instead of an intervention, may allow glutathione levels to be maintained for detoxification in older adults," the researchers wrote.

"I'm optimistic there could be a role for this compound in preventing the increased toxicity we face with aging, as our abilities to deal with toxins decline," Hagen was quoted as saying in a news release from OSU. "We might be able to improve the metabolic resilience that we're naturally losing with age."

Earlier studies suggest that decline of glutathione levels may set the stage for a wide range of age-related health problems, including cardiovascular disease, diabetes and cancer, some of the primary causes of death in the developed world.

"But pretreatment with NAC increased glutathione levels in the older cells and largely helped offset that level of cell death," Hagen said.

Glutathione, he said, is such an important antioxidant that its existence appears to date back as far as oxygen-dependent, or aerobic life itself, about 1.5 billion years ago. It is a principal compound to detoxify environmental stresses, air pollutants, heavy metals, pharmaceuticals and many other toxic insults.

Also of interest, Hagen said, is the apparent detoxification potential offered by glutathione. Higher levels of it might help reduce the toxicity of some prescription drugs, cancer chemotherapies, and treat other health issues.