Hyperuricemia was associated with metabolic response against brain injury instead of metabolism syndrome in Tibet: a cross-sectional analysis

Background To determine if hyperuricemia be a metabolic response to prevent brain injury in high-altitude adaption in Tibet. Methods This cross-sectional study enrolled 3 ethnics of males (18–35 yo) from 3 ascending altitudes ( n = 1133). Metabolic and brain injury biomarkers were compared among the 3 ethnics, and between the normal (NUA) and high serum uric acid (HUA) groups. Results Serum UA levels were simultaneously increased with altitudes in the 3 ethnics (all P < 0.0001), higher in the Hans and Minority than in the Tibetans (both: P < 0.0001). Exclusively in the Hans, xanthine oxidoreductase (XOR) activity was increased ( P < 0.0001) whereas fractional excretion of UA was decreased ( P < 0.0001) with altitudes, meanwhile, HOMA-IR ( P < 0.0001) and HOMA-β ( P = 0.017) were invariably reduced, and GLP-1(1-37a) ( P < 0.0001) was consistently elevated with the altitudes. Beneficially, arteriosclerosis index was elevated with the altitudes in both the Tibetans and the Minorities rather than in the Hans. The level of pan-axonal marker, PGP 9.5, was elevated with altitudes only in the Hans ( P = 0.007), by contrast, the astrocyte marker GFAP were elevated in both the Tibetans ( P = 0.0003) and the Minorities ( P = 0.038) but not in the Hans ( P = 0.13). In comparison of HUA with NUA, while the Hans in shorter stay Lhasa-Yumai showed higher XOR, HOMA-IR, GLP-1(1-37a) and PGP 9.5 levels, PGP9.5 was lower in the Hans in longer stay Lhasa-Tolun; yet both neural biomarkers were elevated in the Tibetans of Lhasa, and tended to decline in Naqu. Conclusion Hyperuricemia may follow distinctive neuroendocrine mechanism among the 3 ethnics to protect the brain from oxidative stress in Tibet.