The administration of BDNF and GDNF to the brain via PLGA microparticles patterned within a degradable PEG-based hydrogel: Protein distribution and the glial response.
Tailored delivery of neurotrophic factors (NFs) is a critical challenge that continues to inhibit strategies for guidance of axonal growth in vivo. Of particular importance is the ability to recreate innervation of distant brain regions by transplant tissue, for instance rebuilding the nigrostriatal track, one focus in Parkinson's disease research. Many strategies have utilized polymer drug delivery to target NF release in space and time, but combinatorial approaches are needed to deliver multiple NFs at relevant therapeutic times and locations without toxic side effects. Here we engineered a paradigm of PLGA microparticles entrapped within a degradable PEG-based hydrogel device to locally release two different types of NFs with two different release profiles. Hydrogel/microparticle devices were developed and analyzed for their ability to release GDNF in the caudal area of the brain, near the substantia nigra, or BDNF in the rostral area, near the striatum. The devices delivered their respective NFs in a region localized to within 100 μm of the bridge, but not exclusively to the targeted rostral or caudal ends. BDNF was slowly released over a 56-day period, whereas a bolus of GDNF was released around 28 days. The timed delivery of NFs from implanted devices significantly reduced the microglial response relative to sham surgeries. Given the coordinated drug delivery ability and reduced localized inflammatory response, this multifaceted PEG hydrogel/PLGA microparticle strategy may be a useful tool for further development in combining tissue engineering and drug delivery, and recreating the nigrostriatal track.
Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado, USA.
Kyle J
KJ
Lampe
Drew S
DS
Kern
Melissa J
MJ
Mahoney
Kimberly B
KB
Bjugstad
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D019208:Brain-Derived Neurotrophic Factor / Q000008:administration & dosage* / Q000494:pharmacology; D002452:Cell Count; D005260:Female; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000008:administration & dosage* / Q000494:pharmacology; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D019344:Lactic Acid / Q000737:chemistry*; D017628:Microglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry*; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D019919:Prosthesis Implantation; D051381:Rats; D017207:Rats, Sprague-Dawley
D019208:Brain-Derived Neurotrophic Factor; D051100:Glial Cell Line-Derived Neurotrophic Factor; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011092:Polyethylene Glycols