The effects of therapeutic hypothermia on cerebral metabolism in neonates with hypoxic-ischemic encephalopathy: An in vivo H-1-MR spectroscopy study

摘要

Therapeutic hypothermia has emerged as the first empirically supported therapy for neuroprotection in neonates with hypoxic-ischemic encephalopathy (HIE). We used magnetic resonance spectroscopy (H-1-MRS) to characterize the effects of hypothermia on energy metabolites, neurotransmitters, and antioxidants. Thirty-one neonates with HIE were studied during hypothermia and after rewarming. Metabolite concentrations (mmol/kg) were determined from the thalamus, basal ganglia, cortical grey matter, and cerebral white matter. In the thalamus, phosphocreatine concentrations were increased by 20% during hypothermia when compared to after rewarming (3.49 +/- 0.88 vs. 2.90 +/- 0.65, p < 0.001) while free creatine concentrations were reduced to a similar degree (3.00 +/- 0.50 vs. 3.74 +/- 0.85, p < 0.001). Glutamate (5.33 +/- 0.82 vs. 6.32 +/- 1.12, p < 0.001), aspartate (3.39 +/- 0.66 vs. 3.87 +/- 1.19, p < 0.05), and GABA (0.92 +/- 0.36 vs. 1.19 +/- 0.41, p < 0.05) were also reduced, while taurine (1.39 +/- 0.52 vs. 0.79 +/- 0.61, p < 0.001) and glutathione (2.23 +/- 0.41 vs. 2.09 +/- 0.33, p < 0.05) were increased. Similar patterns were observed in other brain regions. These findings support that hypothermia improves energy homeostasis by decreasing the availability of excitatory neurotransmitters, and thereby, cellular energy demand.