PURPOSE: Tryptophan (TRP) degradation through the kynurenine pathway is responsible for converting 95% of free TRP into kynurenines, which modulate skeletal muscle bioenergetics, immune and central nervous system activity. Therefore, changes in the kynurenines during exercise have been widely studied but not in the context of the effects of remote ischemic preconditioning (RIPC). In this study, we analyzed the effect of 14-day RIPC training on kynurenines and TRP in runners after running intervals of 20 × 400 m. METHODS: In this study, 27 semi-professional long-distance runners were assigned to two groups: a RIPC group performing 14 days of RIPC training (n = 12), and a placebo group, SHAM (n = 15). Blood was collected for analysis before, immediately after, and at 6 h and 24 h after the run. RESULTS: After the 14-day RIPC/SHAM intervention, post hoc analysis showed a significantly lower concentration of XANA and kynurenic acid to kynurenine ratio (KYNA/KYN) in the RIPC group than in the SHAM group immediately after the running test. Conversely, the decrease in serum TRP levels was higher in the RIPC population. CONCLUSION: RIPC modulates post-exercise changes in XANA and TRP levels, which can affect brain health, yet further research is needed.

• Keywords
• kynurenic acid, limb ischemia, long-distance runner, neuro-protective metabolites, tryptophan, xanthurenic acid,
• Publication type
• Journal Article MeSH

Exercise affects serum levels of amino acids and their metabolites, with important metabolic consequences. Since vitamin D impacts skeletal muscle protein degradation, we hypothesised that it would also impact exercise-induced changes in serum amino acid levels and the serum levels of arginine metabolites, influencing the body's ability to synthesise NO. Accordingly, we analysed the effect of a single high-dose vitamin D supplementation on the serum levels of various amino acids in ultramarathon runners. Thirty-five male amateur runners were assigned to the supplemented group, administered 150,000 IU vitamin D in vegetable oil 24 h before the run (n = 16), or the control (placebo) group (n = 19). Blood was sampled 24 h before, immediately after, and 24 h after the run. Changes in the serum levels of some amino acids were distinct in the two groups. The asymmetric dimethyl arginine levels were significantly decreased immediately after the run and increased 24 h later and were not affected by the supplementation. The symmetric dimethyl arginine levels were increased after the run in both groups but were lower in the supplemented group than in the placebo group 24 h after the run. The dimethylamine levels increased significantly in the supplemented group as compared to the placebo group. In conclusion, vitamin D impacts exercise-induced changes in serum amino acids and methylated arginine metabolites.

• Keywords
• ADMA, SDMA, amino acid, skeletal muscle damage, ultramarathon,
• MeSH
• Amino Acids MeSH
• Arginine * MeSH
• Humans MeSH
• Dietary Supplements MeSH
• Tryptophan * MeSH
• Amino Acids, Branched-Chain MeSH
• Vitamin D MeSH
• Vitamins MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Publication type
• Journal Article MeSH
• Randomized Controlled Trial MeSH
• Names of Substances
• Amino Acids MeSH
• Arginine * MeSH
• N,N-dimethylarginine MeSH Browser
• Tryptophan * MeSH
• Amino Acids, Branched-Chain MeSH
• Vitamin D MeSH
• Vitamins MeSH