BACKGROUND
In a combined animal and human study, we have previously found that a five-day treatment that enhances cortical plasticity also facilitates brain-derived neurotrophic factor (BDNF)-tyrosine receptor kinase B (TrkB) signaling and increases activated TrkB and N-methyl-D-aspartate receptor (NMDAR) association in both the cortex and the peripheral lymphocytes. Patients with Parkinson’s disease (PD) in general show decreased cortical plasticity, as demonstrated by electrophysiological and behavioral studies. Here we test the hypothesis that an exercise program that improves motor function and seems to slow down symptoms’ progression can enhance BDNF-TrkB signaling in lymphocytes.
METHODS
Sixteen patients with PD underwent a four-week Multidisciplinary Intensive Rehabilitation Treatment (MIRT), which included aerobic training, physical and occupational therapy. Blood was collected before, after two- and four-week MIRT. Lymphocytes were isolated to examine BDNF-TrkB signaling induced by incubation with recombinant human BDNF. TrkB signaling complexes, extracellular-signal-regulated kinase-2 and protein-kinase-B were immunoprecipitated; content of immunocomplexes was determined by Western blotting.
RESULTS
After MIRT, all patients showed improvement in motor function. TrkB interaction with NMDAR and BDNF-TrkB signaling increased in peripheral lymphocytes at receptor, intracellular mediators and downstream levels. The decrements in UPDRSII and total scores were significantly correlated with the increases in TrkB signaling at receptor, intracellular mediators and NMDAR interaction levels.
CONCLUSIONS
The significant correlation between reduced UPDRS scores and the changes in lymphocytes’ activity suggest that enhanced BDNF-TrkB signaling in lymphocyte and reduced severity of PD symptoms may be related.