Plasma methionine metabolic profile is associated with longevity in mammals.

Methionine metabolism arises as a key target to elucidate the molecular adaptations underlying animal longevity due to the negative association between longevity and methionine content. The present study follows a comparative approach to analyse plasma methionine metabolic profile using a LC-MS/MS platform from 11 mammalian species with a longevity ranging from 3.5 to 120 years. Our findings demonstrate the existence of a species-specific plasma profile for methionine metabolism associated with longevity characterised by: i) reduced methionine, cystathionine and choline; ii) increased non-polar amino acids; iii) reduced succinate and malate; and iv) increased carnitine. Our results support the existence of plasma longevity features that might respond to an optimised energetic metabolism and intracellular structures found in long-lived species.

Rapamycin reverses age-related increases in mitochondrial ROS production at complex I, oxidative stress, accumulation of mtDNA fragments inside nuclear DNA, and lipofuscin level, and increases autophagy, in the liver of middle-aged mice.

Rapamycin consistently increases longevity in mice although the mechanism of action of this drug is unknown. In the present investigation we studied the effect of rapamycin on mitochondrial oxidative stress at the same dose that is known to increase longevity in mice (14mgofrapamycin/kg of diet). Middle aged mice (16months old) showed significant age-related increases in mitochondrial ROS production at complex I, accumulation of mtDNA fragments inside nuclear DNA, mitochondrial protein lipoxidation, and lipofuscin accumulation compared to young animals (4months old) in the liver. After 7weeks of dietary treatment all those increases were totally or partially (lipofuscin) abolished by rapamycin, middle aged rapamycin-treated animals showing similar levels in those parameters to young animals. The decrease in mitochondrial ROS production was due to qualitative instead of quantitative changes in complex I. The decrease in mitochondrial protein lipoxidation was not due to decreases in the amount of highly oxidizable unsaturated fatty acids. Rapamycin also decreased the amount of RAPTOR (of mTOR complex) and increased the amounts of the PGC1-α and ATG13 proteins. The results are consistent with the possibility that rapamycin increases longevity in mice at least in part by lowering mitochondrial ROS production and increasing autophagy, decreasing the derived final forms of damage accumulated with age which are responsible for increased longevity. The decrease in lipofuscin accumulation induced by rapamycin adds to previous information suggesting that the increase in longevity induced by this drug can be due to a decrease in the rate of aging.

Cysteine dietary supplementation reverses the decrease in mitochondrial ROS production at complex I induced by methionine restriction.

It has been described that dietary cysteine reverses many of the beneficial changes induced by methionine restriction in aging rodents. In this investigation male Wistar rats were subjected to diets low in methionine, supplemented with cysteine, or simultaneously low in methionine and supplemented with cysteine. The results obtained in liver showed that cysteine supplementation reverses the decrease in mitochondrial ROS generation induced by methionine restriction at complex I. Methionine restriction also decreased various markers of oxidative and non-oxidative stress on mitochondrial proteins which were not reversed by cysteine. Instead, cysteine supplementation also lowered protein damage in association with decreases in mTOR activation. The results of the present study add the decrease in mitochondrial ROS production to the various beneficial changes induced by methionine restriction that are reversed by cysteine dietary supplementation.

Determination of 4-ethylguaiacol and 4-ethylphenol in red wines using headspace-solid-phase microextraction-gas chromatography.

A method for analysing 4-ethylguaiacol and 4-ethylphenol in the aroma of red wines using headspace-solid-phase microextraction is presented. The fibres used were coated with 100 microm of polydimethylsiloxane. Parameters like ionic strength, agitation of the sample, sample volume, temperature of the sample and adsorption/desorption times were studied and optimised to obtain the best extraction results. The linearity of the response was studied in the usual concentration ranges in wines (4-ethylguaiacol, 40-400 microg/l; 4-ethylphenol, 200-1800 microg/l). Repeatability of the method was determined, and the relative standard deviation was about 10%. Limits of detection and limits of quantification were also determined, and the values found were 1 and 5 microg/l for 4-ethylguaiacol and 2 and 5 microg/l for 4-ethylphenol, respectively. All these values were under the sensory thresholds established for these volatile phenols. The presence of interferences due to the matrix composition implies the use of the standard addition technique for both compounds quantification.