(355c) Engineering Nanomedicine to Overcome Brain Biological Barriers for Improved Treatment of Pediatric Brain Diseases

Background/Motivation: When delivery limitations of a nanoparticle platform are better understood, an optimal formulation can be engineered and evaluated for therapeutic efficacy in clinically relevant animal models of brain disease. We focus on developing nanoparticle-based therapeutic approaches for improved neurological outcomes in perinatal brain injury, specifically those where neuroinflammation, oxidative stress, and excitotoxicity play key roles. Our area of application in pediatric and neonatal brain disease/injury models is motivated by several key factors: (1) technology development for these patient populations is vastly underserved, (2) there is currently no effective cure for any neurological disease that affects a newborn, and these diseases can persist over a lifetime, which results in opportunity to have impact, and (3) animal models in this field are well established and several of these models are reproducible across multiple labs, enabling higher likelihood of success for clinical translation.

Methods overview: We have focused on therapeutic nanoparticle platforms that are polymer-based, incorporate materials that are FDA approved, and have been utilized extensively in adult populations but have not been used in children or newborns. We have identified drugs that can affect multiple pathways and have a solubility and/or delivery problem - that is, the drug is either not soluble in aqueous solutions or it is not able to reach its target site in high enough concentrations to be effective. With these in mind, we use poly(lactic-co-glycolic)(PLGA)-poly(ethylene glycol) (PEG) copolymer platforms for delivery of several therapeutics, including curcumin, catalase, superoxide dismutase (SOD), and nicotinamide riboside (NR). We use a range of in vitro, ex vivo, and in vivo models to screen and evaluate efficacy of nanotherapeutic platforms. Our ex vivo cultures include stimuli that replicate aspects of in vivo injury conditions, such as oxygen-glucose deprivation, glutamate toxicity, or exposure to lipopolysaccharide (LPS). In vitro and ex vivo, we test for toxicity and dose response; ex vivo, we evaluate regionally dependent cellular uptake and downstream mechanistic effects of the nanotherapeutic platform; in vivo, we quantify biodistribution and measure improvements in gross injury and neuropathology in response to treatment.

Results: Our main contribution in this space thus far showed curcumin, a broad acting anti-inflammatory and anti-oxidant agent, could safely be delivered in PLGA-PEG nanoparticles to neonatal rats. We demonstrated that curcumin-loaded PLGA-PEG nanoparticles could reduce brain injury via gross injury analysis and neuropathology in neonatal rats with hypoxic-ischemic (HI) brain injury. The application of curcumin and PLGA-PEG nanoparticle-mediated delivery to a clinically-relevant model of neonatal brain injury provides opportunity for clinical translation of targeted therapies for HIE. We recently expanded on this work to show that SOD can be an effective treatment against HI injury in cultured rat brain slices, and screened promising preclinical therapeutics in a ferret brain slice model of HI injury. Importantly, we’ve furthered our targeting capabilities by showing how the (1) disease severity alters nanoparticle-cellular interactions, (2) formulation conditions can impart pathology-specific toxicity, and (3) surfactant used to stabilize PLGA-PEG formulations can direct site-specific cell-specific uptake in the neonatal brain.

Conclusions: Of the current clinically approved nanotechnologies in 2019, none are indicated for non-cancerous neurological disease, which represents 13% of the global disease burden. Therefore, our lab has worked to develop tools that inform how we can more effectively treat the diseased brain, using nanotechnology as both a probe and as a therapeutic delivery vehicle. In this talk, we demonstrate the importance of using multiple platforms to evaluate nanotherapeutic behavior in the brain, and the impact formulation methods can have on polymeric nanoparticle effect and fate in the brain. Further, we show that we can engineer more effective nanotherapeutics for the treatment of neurological disease with a specific emphasis on the neonatal and pediatric populations, which are vastly underserved by technology development.