The molecular structure of ß-alanine is resistant to sterilising doses of gamma radiation.

ß-alanine is the rate-limiting point for the endogenous synthesis of carnosine in skeletal muscle. Carnosine has a wide range of implications for health, normal function and exercise performance. Whilst the physiological relevance of carnosine to different tissues remains enigmatic, ß-alanine administration is a useful strategy to investigate the physiological roles of carnosine in humans. Intravenous administration of ß-alanine is an interesting approach to study carnosine metabolism. However, sterilisation is mandatory due to the nature of the administration route. We evaluated whether sterilising doses of gamma radiation damages the molecular structure and leads to the loss of functional characteristics of ß-alanine. Pure ß-alanine was sterilised by gamma radiation in sealed glass vials using a 60Co multipurpose irradiator at a dose rate of 8.5 kGy.hour-1 totalising 10, 20, 25 30 and 40 kGy. The molecular integrity was assessed by X-ray Diffraction and changes in content were determined by High Performance Liquid Chromatography (UV-HPLC) and Triple Quadrupole Mass Spectrometer (HPLC/MS-MS). Sterility assurance was evaluated by inoculation assay. To examine whether functional properties were preserved, ß-alanine was infused in one participant, who rated the level of paraesthesia on the skin using a 0-3 scale. Urinary ß-alanine was quantified before and 24-h following ß-alanine infusion using HPLC-ESI+-MS/MS. Irradiation resulted in no change in the crystal structure of ß-alanine, no degradation, and no new peaks were identified in the dose range assayed. The inoculation assay showed the absence of viable microorganisms in all ß-alanine samples, including those that did not undergo irradiation. Intravenous infusion of ß-alanine resulted in paraesthesia and it detected in the urine as per normal. We conclude that gamma radiation is a suitable technique for the sterilisation of ß-alanine. It does not lead to degradation, damage to the ß-alanine structure, content or loss of function within the evaluated irradiation conditions.

Exercise and ß-alanine supplementation on carnosine-acrolein adduct in skeletal muscle.

Previous studies have demonstrated that exercise results in reactive aldehyde production and that ß-alanine supplementation increases carnosine content in skeletal muscle. However, little is known about the influence exercise and ß-alanine supplementation have on the formation of carnosine-aldehydes. The goal of the present study was to monitor the formation of carnosine-aldehyde adducts, following high-intensity intermittent exercise, before and after ß-alanine supplementation. Vastus lateralis biopsy samples were taken from 14 cyclists, before and after a 28 day ß-alanine supplementation, following 4 bouts of a 30 s all-out cycling test, and carnosine and CAR-aldehyde adducts [carnosine-acrolein, CAR-ACR (m/z 303), carnosine-4-hydroxy-2-hexenal, CAR-HHE (m/z 341) and carnosine-4-hydroxy-2-nonenal, CAR-HNE (m/z 383)] were quantified by HPLC-MS/MS. ß-alanine supplementation increased muscle carnosine content by ~50% (p = 0.0001 vs. Pre-Supplementation). Interestingly, there was a significant increase in post-exercise CAR-ACR content following ß-alanine supplementation (p < 0.001 vs. post-exercise before supplementation), whereas neither exercise alone nor supplementation alone increased CAR-ACR formation. These results suggest that carnosine functions as an acrolein-scavenger in skeletal muscle. Such a role would be relevant to the detoxification of this aldehyde formed during exercise, and appears to be enhanced by ß-alanine supplementation. These novel findings not only have the potential of directly benefiting athletes who engage in intensive training regimens, but will also allow researchers to explore the role of muscle carnosine in detoxifying reactive aldehydes in diseases characterized by abnormal oxidative stress.

DNA Adduct Formation in the Lungs and Brain of Rats Exposed to Low Concentrations of [13C2]-Acetaldehyde.

Air pollution is a major environmental risk for human health. Acetaldehyde is present in tobacco smoke and vehicle exhaust. In this study, we show that [13C2]-acetaldehyde induces DNA modification with the formation of isotopically labeled 1, N2-propano-2'-deoxyguanosine adducts in the brain and lungs of rats exposed to concentrations of acetaldehyde found in the atmosphere of megacities. The adduct, with the addition of two molecules of isotopically labeled acetaldehyde [13C4]-1, N2-propano-dGuo, was detected in the lung and brain tissues of exposed rats by micro-HPLC/MS/MS. Structural confirmation of the products was unequivocally performed by nano-LC/ESI+-HRMS3 analyses. DNA modifications induced by acetaldehyde have been regarded as a key factor in the mechanism of mutagenesis and may be involved in the cancer risks associated with air pollution.