Optimization of brain metabolism using metabolic-targeted therapeutic hypothermia can reduce mortality from traumatic brain injury.

BACKGROUND: Therapeutic hypothermia is widely used to treat traumatic brain injuries (TBIs). However, determining the best hypothermia therapy strategy remains a challenge. We hypothesized that reducing the metabolic rate, rather than reaching a fixed body temperature, would be an appropriate target because optimizing metabolic conditions especially the brain metabolic environment may enhance neurologic protection. A pilot single-blind randomized controlled trial was designed to test this hypothesis, and a nested metabolomics study was conducted to explore the mechanics thereof. METHODS: Severe TBI patients (Glasgow Coma Scale score, 3-8) were randomly divided into the metabolic-targeted hypothermia treatment (MTHT) group, 50% to 60% rest metabolic ratio as the hypothermia therapy target, and the body temperature-targeted hypothermia treatment (BTHT) control group, hypothermia therapy target of 32°C to 35°C body temperature. Brain and circulatory metabolic pool blood samples were collected at baseline and on days 1, 3, and 7 during the hypothermia treatment, which were selected randomly from a subgroup of MTHT and BTHT groups. The primary outcome was mortality. Using H nuclear magnetic resonance technology, we tracked and located the disturbances of metabolic networks. RESULTS: Eighty-eight severe TBI patients were recruited and analyzed from December 2013 to December 2014, 44 each were assigned in the MTHT and BTHT groups (median age, 42 years; 69.32% men; mean Glasgow Coma Scale score, 6.17 ± 1.02). The mortality was significantly lower in the MTHT than the BTHT group (15.91% vs. 34.09%; p = 0.049). From these, eight cases of MTHT and six cases from BTHT group were enrolled for metabolomics analysis, which showed a significant difference between the brain and circulatory metabolic patterns in MTHT group on day 7 based on the model parameters and scores plots. Finally, metabolites representing potential neuroprotective monitoring parameters for hypothermia treatment were identified through H nuclear magnetic resonance metabolomics. CONCLUSION: MTHT can significantly reduce the mortality of severe TBI patients. Metabolomics research showed that this strategy could effectively improve brain metabolism, suggesting that reducing the metabolic rate to 50% to 60% should be set as the hypothermia therapy target. LEVEL OF EVIDENCE: Therapeutic study, Level I.

Janus-type AT nucleosides: synthesis, solid and solution state structures.

Novel Janus-type nucleoside analogues (1a-d) were synthesized. Their pyrimido[4,5-d]pyrimidine base moiety has one face with a bidentate Watson-Crick donor-acceptor (DA) H-bond array of adenine and the other face with an acceptor-donor (AD) H-bond array of thymine. These nucleosides may self-associate through the self-complementary base pair. Indeed, in the solid state, compound 6d displayed a honeycomb-like supramolecular structure with tetrameric membered cavities formed through the combination of reverse Watson-Crick base pairs and aromatic stacking, in which the solvent molecules were accommodated. The result of temperature-dependent CD studies showed that the free nucleosides can form higher order chiral structures in aqueous solution.