Assessment of oxidative stress biomarkers – neuroprostanes and dihomo-isoprostanes – in the urine of elite triathletes after two weeks of moderate-altitude training

ABSTRACT

This randomized and controlled trial investigated whether the increase in elite training at different altitudes altered the oxidative stress biomarkers of the nervous system. This is the first study to investigate four F₄-neuroprostanes (F₄-NeuroPs) and four F₂-dihomo-isoprostanes (F₂-dihomo-IsoPs) quantified in 24-h urine. The quantification was carried out by ultra high pressure liquid chromatography-triple quadrupole-tandem mass spectrometry (UHPLC-QqQ-MS/MS). Sixteen elite triathletes agreed to participate in the project. They were randomized in two groups, a group submitted to altitude training (AT, n = 8) and a group submitted to sea level training (SLT) (n = 8), with a control group (Cg) of non-athletes (n = 8). After the experimental period, the AT group triathletes gave significant data: 17-epi-17-F_2t-dihomo-IsoP (from 5.2 ± 1.4 μg/mL 24 h⁻¹ to 6.6 ± 0.6 μg/mL 24 h⁻¹), ent-7(RS)-7-F_2t-dihomo-IsoP (from 6.6 ± 1.7 μg/mL 24 h⁻¹ to 8.6 ± 0.9 μg/mL 24 h⁻¹), and ent-7-epi-7-F_2t-dihomo-IsoP (from 8.4 ± 2.2 μg/mL 24 h⁻¹ to 11.3 ± 1.8 μg/mL 24 h⁻¹) increased, while, of the neuronal degeneration-related compounds, only 10-epi-10-F_4t-NeuroP (8.4 ± 1.7 μg/mL 24 h⁻¹) and 10-F_4t-NeuroP (5.2 ± 2.9 μg/mL 24 h⁻¹) were detected in this group. For the Cg and SLT groups, no significant changes had occurred at the end of the two-week experimental period. Therefore, and as the main conclusion, the training at moderate altitude increased the F₄-NeuroPs- and F₂-dihomo-isoPs-related oxidative damage of the central nervous system compared to similar training at sea level.

KEYWORDS:

• Altitude
• dihomo-isoprostanes
• neuroprostanes
• oxidative stress
• physical exercise
• UHPLC-QqQ-MS/MS

Acknowledgements

We are grateful to Dr. David Walker for the review of the English grammar and style of the current report.

Disclosure statement

The authors declare that they have no conflict of interest.

Funding information

This study was supported by the project AGL2011-23690 (CICYT) (Spanish Ministry of Economy and Competitiveness). L.A.G.F. was granted a pre-doctoral FPI fellowship (BES2012-060185) by the Spanish government. The authors are also grateful to the University of Alicante for its collaboration. S.M. was appointed under a research contract from the project AGL2011-23690 (CICYT).