Creatine supplementation reduces the cerebral oxidative and metabolic stress responses to acute in utero hypoxia in the late-gestation fetal sheep.

"raw arterial blood gases and metabolites (-30 min +9 min and +72 h relative to uco) are reported in supplementary data s2 .; there were no time or interaction effects for 2-oh-ta concentrations in the dialysate outflow across any of the post-uco time intervals (supplementary data s1 ).; however creatine treatment led to a decrease in the 2-oh-ta concentration compared to saline fetuses during the early recovery phase (0-8 h post-uco; f (1 10) = 4 96 p treat = 0 050; fig 1 ; supplementary data s1 ).; there were no interaction or creatine treatment effects for any of the metabolite concentrations across any recovery time period following uco (supplementary data s1 ).; the uco induced a rise in pyruvate lactate and glycerol concentrations in the cerebral interstitial fluid with a similar temporal pattern identified in both saline- and creatine-treated fetuses during the early recovery stage (0-8 h post-uco; f (1 72 12 45) = 7 39 p time = 0 009; f (2 05 14 35) = 4 79 p time = 0 025 and f (2 26 16 38) = 6 24; p time = 0 008 respectively fig 2 a-c supplementary data s1 ).; glycerol concentrations remained affected 9-24 h following uco irrespective of treatment ( f (3 55 27 49) = 2 94 p time = 0 043; supplementary data s1 ) and returned by late recovery (>24 h post-uco).; levels of glycine and glutamate were not affected by uco though there was a near-to-significant interaction between time and creatine treatment during the late recovery period for glycine concentrations ( f (8 63) = 1 98 p int = 0 064) (fig 2 d and e supplementary data s1 ).; overall there were significant associations between fetal arterial creatine concentrations arterial p o 2 and s o 2 and the cumulative percentage change of cerebral interstitial pyruvate lactate and 2-oh-ta (fig 3 ; supplementary data s3 ).; the level of arterial creatine was positively correlated with the percentage change of p o 2 and s o 2 which were then negatively associated with percentage change in cerebral pyruvate accumulation suggesting that higher levels of arterial creatine and reduced changes in arterial p o 2 and s o 2 during uco resulted in lower levels of pyruvate accumulation ( p = 0 006 and p < 0 0001 respectively; fig 3 ; supplementary data s3 ).; a similar relationship between higher levels of creatine and reduced changes in arterial s o 2 during uco resulting in lower levels of cerebral lactate accumulation was also found ( p = 0 017; fig 3 ; supplementary data s3 ).; in addition a significant relationship between arterial creatine arterial p o 2 and cerebral 2-oh-ta was observed in which higher arterial creatine and reduced changes in p o 2 during uco was associated with lower cerebral 2-oh-ta levels ( p = 0 050; fig 3 ; supplementary data s3 ).; there were no correlations between the total magnitude of change of 2-oh-ta following uco on the cell density of 4-hne and 3-nt positive immunostaining within the scwm and gm (supplementary data s4 ).; supplementary data s1 .; supplementary data s2 .; supplementary data s3 .; supplementary data s4 ."

"Competing interests The authors declare that they have no competing interests."

"Funding N.T.T. was supported by a PhD scholarship from the School of Health & Biomedical Sciences, RMIT University. This research was supported by a grant to D.W.W., R.J.S. and S.J.E. from the National Health & Medical Research Council of Australia (1124493), and to D.W.W. and S.J.E. from the Victorian Government Infrastructure Support Scheme. S.J.E. was supported by Australian National Health and Medical Research Council (NHMRC) Early Career Fellowship (1125539)."