34 research outputs found
Response to "Approaches and Limitations to Gene Therapy for Mitochondrial Diseases," Antioxid. Redox Signal.
Mitochondrial mutations and aging: random drift is insufficient to explain the accumulation of mitochondrial deletion mutants in short‐lived animals
A model of aging as accumulated damage matches observed mortality patterns and predicts the life-extending effects of prospective interventions
The relative insensitivity of lifespan to environmental factors constitutes compelling evidence that the physiological decline associated with aging derives primarily from the accumulation of intrinsic molecular and cellular side-effects of metabolism. Here we model that accumulation starting from a biologically based interpretation of the way in which those side-effects interact. We first validate this model by showing that it very accurately reproduces the distribution of ages at death seen in typical populations that are well protected from age-independent causes of death. We then exploit the mechanistic basis of this model to explore the impact on lifespans of interventions that combat aging, with an emphasis on interventions that repair (rather than merely retard) the direct molecular or cellular consequences of metabolism and thus prevent them from accumulating to pathogenic levels. Our results strengthen the case that an indefinite extension of healthy and total life expectancy can be achieved by a plausible rate of progress in the development of such therapies, once a threshold level of efficacy of those therapies has been reached
Medical bioremediation: Prospects for the application of microbial catabolic diversity to aging and several major age-related diseases
Yeast, Plants, Worms, and Flies Use a Methyltransferase to Metabolize Age-Damaged (R,S)-AdoMet, but What Do Mammals Do?
The biological methyl donor S-adenosyl-l-methionine [(S,S)-AdoMet] can spontaneously break down under physiological conditions to form the inactive diastereomer (R,S)-AdoMet, which may interfere with cell function. Although several lower organisms metabolize (R,S)-AdoMet via homocysteine methyltransferases, it is unclear how mammals deal with it. In this paper, we show that the mouse liver extracts, containing the BHMT-2 homocysteine methyltransferase candidate for a similar activity, recognizes (S,S)-AdoMet but not (R,S)-AdoMet. We find no evidence for the enzymatic breakdown of (R,S)-AdoMet in these extracts. Thus, mammals may metabolize (R,S)-AdoMet using a different strategy than other organisms