Abstract Body:

Background and Purpose: The inflammatory response after ischemic and hemorrhagic stroke is associated with worse clinical outcomes through immune mediated production of pro- inflammatory cytokines. Repair proteins such as brain derived neurotrophic factor (BDNF) are expressed as part of the adaptive immune response. We assessed safety of moderate intensity exercise in the acute phase and its association with pro-inflammatory cytokines and BDNF expression.
Methods: This was a prospective, single center, randomized, pilot of prescribed exercise for patients hospitalized with stroke. The intervention group was randomized to standard care plus two 20-minute in-bed cycle ergometry sessions per day during the first week after stroke. We measured serum concentrations of BDNF as primary outcome and interleukin(IL)-1β IL-6, IL-10, tumor necrosis factor(TNF)-α and National Institutes of Health Stroke Scale (NIHSS) score as secondary outcomes at days 1(T1), 3(T2) and 7(T3). Cerebrospinal fluid was collected in 4 patients with an external ventricular drain. We used Spearman’s Rho to assess associations of biomarker levels with treatment group.
Results: A total of 15 patients with acute spontaneous intracerebral hemorrhage (ICH) and nine patients with acute ischemic stroke (AIS) were enrolled. Of 25 enrolled patients, mean age was 65.8 (SD, 16.3) years, and 10 (40%) were female. Median admission NIHSS score was 12 (interquartile range 6-17) in the intervention group (n=14) compared to 19 (14-24) in the control group (n=11). Seventy-four cycling sessions were performed in the intervention group for a mean of 98.9 (sd, 59.1) total minutes of cycling per patient. In the combined AIS/ICH cohort, a trend association of increased BDNF was observed at T2 in the intervention group compared to the control group (p=0.05). No serious adverse events were recorded.
Conclusions: This is one of the first human trials to investigate exercise-induced modulation of inflammatory cytokine and trophic factor expression in the first week after stroke. Early moderate intense exercise was safe and showed small but promising changes in BDNF despite imbalances in clinical factors in this small study.