Curcumin-Loaded Polymeric Nanoparticles for Neuroprotection in Neonatal Rats with Hypoxic-Ischemic Encephalopathy (HIE)

Thesis (Master's)--University of Washington, 2017-06Hypoxic-ischemic encephalopathy (HIE) is the leading cause of permanent brain injury and is due to a reduction in the supply of oxygen, compounded by low blood flow to the brain. Moderate to severe HIE is the major cause of morbidity and mortality in neonates around the time of birth. Current experimental evidence and clinical trials suggest that therapeutic hypothermia (TH) can reduce brain damage and improve neurological outcomes after neonatal hypoxic-ischemic (HI) injury. However, some infants still die and nearly half of affected infants continue to have significant brain injury in spite of treatment with TH. Therefore, additional treatment options should be explored. Curcumin has recently been found to have antioxidant, anti-inflammatory and anti-apoptotic effects that may mitigate the outcomes of brain injury after perinatal asphyxia. Nonetheless, curcumin has low solubility and limited ability to cross the blood-brain barrier (BBB). Several studies show that nanoparticles have the ability to cross the BBB, and incorporation of curcumin into a nanoparticle platform can overcome therapeutic limitations for effective use. After crossing the BBB, nanoparticles must have the ability to travel through the brain parenchyma to reach diseased cells and deliver a therapeutic. Previously it has been found that poly(ethylene glycol) (PEG)-coated polystyrene particle less than 114 nm in diameter with a zeta (ζ)-potential more neutral than -6 mV can penetrate within the brain parenchyma. Using this criteria, the biodegradable polymer methoxy(polyethylene glycol)-poly(lactic-co-glycolic acid) (mPEG-PLGA) was used to prepare curcumin-loaded nanoparticles. The impact of nanoparticle formulation parameters on nanoparticle’ size and ζ-potential was investigated. Curcumin loading and curcumin release kinetics from the nanoparticle were also studied. In addition, nanoparticle transport behavior in a rat brain ex vivo model was studied using a high resolution multiple particle tracking technique. The brain localization and biodistribution of the nanoparticle and preliminary efficacy study of the curcumin-loaded nanoparticle was studied in a postnatal day 7 (P7) HI rat model. It was found that the nanoprecipitation method is a feasible method to formulate both curcumin-loaded mPEG5k-PLGA45k (50:50) and PLGA45k (50:50) nanoparticles with 5 – 6% curcumin loading. mPEG5k-PLGA45k (50:50) surface-coated with 1% F127 had better mobility within the brain parenchyma than PLGA45k (50:50) and both nanoparticles had good stability and sustained curcumin release within 24 hours. Preliminary results also showed that mPEG5k-PLGA45k (50:50) was able to get into the brain and curcumin-loaded mPEG5k-PLGA45k (50:50) increased curcumin passage across the BBB and reduced neuronal injury in the HIE rat model