014 - Allopregnanolone (ALLO), the pregnancy neuro-steroid, is neuroprotective in hypoxic-ischemic injury of the immature brain.

Publication Number: 14.3672

Nahla Zaghloul, University of Florida, gainesville, FL, United States; Gupta Akash, University of Arizona, Tucson, AZ, United States; Mohamed Ahmed, UF Health Shands Children's Hospital, Gainesville, FL, United States

Background: Hypoxic ischemic (HI) brain injury in premature infants is the most common cause of cerebral palsy (CP). Yearly, 40,000 infants born prematurely suffer from major cognitive
deficits and 7,000 develop CP. No current therapy can reverse or ameliorate HI and its sequelae. Therefore, there is an urgent need to develop safe natural therapeutic like Allopregnanolone (ALLO), an endogenous neuro-steroid essential for brain growth, neuronal and glial cell survival. Premature infants born are devoid of a placental supply of ALLO.

Objective: We hypothesize that ALLO administration can ameliorate brain injury in a HI neonate mouse model, by promoting neurogenesis, neuro-regeneration and oligodendrogenesis while reducing neuro-inflammation and glutamate excitotoxicity.

Design/Methods: ALLO assay was done using umbilical cord blood collected from human neonates with a gestational age range between 23-38 weeks of gestation. Animal studies: A neonate mouse model of HI was treated with 3 doses of ALLO (10mg/kg/dose IP) on P5, P8 and P11. Another group with HI was treated with saline. Some of the studied animal groups were sacrificed on P12 for molecular, biochemical, histopathological, and transcriptome studies. Others were allowed to survive till P60 for neurobehavioral studies.

Results: Human ALLO plasma levels at birth were 9 times higher in term infants compared to extreme preterm infants. ALLO-treated HI mice showed significant improvement in neuro-regeneration, myelination, motor function, coordination, learning and memory, along with significant attenuation of neuro-inflammation. RNA sequencing analysis showed that ALLO-treated HI group has a significant downregulation of inflammatory responsive genes, significant reduction of glutamate excito-toxicity, improved neurogenesis and neural repair restoring neural integrity and cognitive function. Mitochondrial ultrastructure in hippocampal neurons, using electron microscopy, showed small, fragmented mitochondria, with loss of mitochondrial membrane and cristae in HI group, while ALLO protected mitochondrial ultrastructure after HI exposure. ALLO significantly reversed deficits in biogenesis and key mitochondrial enzyme activity and reduced lipid peroxidation in HI.

Conclusion(s): Our data showed that ALLO is a unique natural neuro-therapeutic steroid in HI injury. ALLO supplementation can lead to a decrease in CP incidence and severity; by promoting neurogenesis, neuro-regeneration and oligodendrogenesis, while reducing neuro-inflammation and glutamate excito-toxicity and preserving mitochondrial structure and function.