Optimizing Neuroprotective Strategies for HIE in Low- and Middle-Resource Settings (LMIC neuroprotection) - PROJECT SUMMARY Perinatal asphyxia and subsequent acute hypoxic-ischemic encephalopathy (HIE) affects 1.3-4.7/1000 liveborn infants in the US, with the rate at least 2-3-fold higher in low- and middle-income countries (LMICs). Without treatment, two thirds of affected infants die or develop severe neurodevelopmental impairments including intellectual disability, cerebral palsy and epilepsy. Therapeutic hypothermia (TH) has been the standard of care for infants with moderate or severe HIE since 2010; however, the use of TH outside of the high resource setting is not warranted and may be deleterious. As the greatest burden of HIE is in countries that do not have access to the facilities or patient population suitable to provision of TH, finding appropriate therapies for HIE in LMICs is critical. Important differences in the LMIC patient population include evidence of more chronic hypoxia-ischemia (HI), earlier neonatal seizures, and a higher prevalence of poor nutrition. These conditions result in a shift of injury from the deep grey matter to the white matter, but are generally not modeled in preclinical HIE research. To screen and test for LMIC-relevant neuroprotective agents, we have developed complementary in vitro and in vivo models in the developing ferret. Our data in the inflammation sensitized hypoxic-ischemic-hyperoxic (HIH) ferret model of HIE shows injury patterns and behavioral changes consistent with a greater white matter injury that responds to pharmacological neuroprotectants such as erythropoietin (Epo), but not TH. In cultured organotypic ferret brain slices exposed to simulated nutrient deprivation and intermittent oxygen-glucose deprivation (iOGD), we have also shown similar injury patterns, with the white matter being particularly susceptible to nutrient deprivation. We also see region-dependent responses to multiple therapies, suggesting that an optimal therapeutic approach will require combinatorial therapies to provide global neuroprotection and improve long-term outcomes. Building on our preliminary findings, the objectives of our proposed research are to (1) determine the regional specificity and efficacy of multiple promising neurotherapeutic combinations in the in vitro iOGD slice culture model with nutrient deprivation, (2) evaluate dose-dependent treatment interactions and transcriptomic responses to established and novel neurotherapeutic combinations to optimize white matter neuroprotection in vitro, and (3) develop a cocktail of neurotherapeutics optimizing neuroprotection in vivo in the ferret HIH model using ferret-specific physiologically-based pharmacokinetic models. All the included therapeutics are cost-effective, shelf-stable, and do not require specialist equipment to administer or monitor. Our overarching hypotheses are that: (1) neurotherapeutics that provide complementary region-specific neuroprotection in vitro will increase global neuroprotection in vivo, and (2) that compared to monotherapy, combining complementary neurotherapeutics will result in greater neuroprotection across the entire brain that persists into adolescence. Data resulting from this proposal could support a clinical trial in this population for which no specific neuroprotective therapies are currently available.
