GDNF and cerebellar degeneration: Glial cell derived neurotrophic factor (GDNF) has a short in vivo half-life, but delivery in PLGA microparticles increased half-life, improved motor function and dopaminergic neuron restoration, with no adverse effects on immunogenicity, cerebellar degeneration, or weight loss in vivo (Garbayo et al., 2016).