A new approach in treating neonatal hypoxic-ischaemic and infection sensitised hypoxic-ischaemic brain damage

Neonatal hypoxia-ischemia (HI) brain injury is a leading cause of death, with high morbidity. The clinical manifestation is more severe in cases of pre-exposure to bacterial infections, and no effective treatments are currently available for infection-sensitised HI damage. We hypothesised that two compounds would have a therapeutic activity in HI brain injury: AnxV, a widely used apoptotic marker that is suggested to interact with bacterial membranes, and curcumin, a plant-derived compound with anti-inflammatory, antioxidative and anti-apoptotic properties. AnxV mechanism of action was evaluated through biophysics membrane interaction techniques and lipid binding assays, using different components of bacterial membranes. AnxV displayed cooperative kinetics in binding to LipidA, but not to LPS. Following, AnxV was then used as a treatment in a mouse model for neonatal HI and infection-sensitised HI, showing neuroprotective effects in normal HI, and partial protection in infection-sensitised HI. Importantly, infrared labelled AnxV was observed to cross the blood-brain barrier and accumulate at the site of injury. The intraperitoneal administration of curcumin in DMSO solution to HI animals showed clear neuroprotection in a dose-dependent fashion. However, the toxicity of DMSO and the poor bioavailability of curcumin necessitated further optimisation to make the product suitable for clinical use. We synthesised curcumin-loaded nanoparticles that showed a much slower rate of release in vitro than what was observed for free curcumin. In neonatal HI, the intranasal administration of the curcumin nanoparticles resulted in reduced astrogliosis and tissue loss. Finally, we focused on combining the targeting ability of AnxV with curcumin neuroprotection to maximise the therapeutic benefits. For this purpose, AnxV-functionalised curcumin-loaded nanoparticles were generated and future studies should focus on optimising this formulation. In conclusion, both AnxV and curcumin were neuroprotective in neonatal HI and combining the two treatments could generate beneficial effects to an even greater level than was achieved with either compound individually.