Acute exercise during hemodialysis prevents the decrease in natural killer cells in patients with chronic kidney disease: a pilot study

To evaluate the acute response of natural killer (NK) cell subsets of chronic kidney disease patients submitted to intradialytic exercise in a randomized crossover study. Nine patients were submitted to a single bout of 20-min intradialytic exercise and a control hemodialysis (HD) session with an interval of 7 days between them. Peripheral blood sample was collected at baseline, during HD and immediately after HD in each trial to evaluate the peripheral frequency of NK cells and their subsets (CD3-CD56(bright) and CD3-CD56(dim)), systemic cortisol concentrations, C-reactive protein (CRP), creatine kinase activity (CK), and urea and creatinine levels. HD therapy induced a significant decrease in NK cells frequency (p = 0.039), NK CD3-CD56(bright) cells (p = 0.04), and CD3-CD56(dim) cells (p = 0.036). On the other hand, no significant alterations were observed in NK cells and NK subsets during and after intradialytic exercise trial (p > 0.05). Neither trial altered CRP levels or serum CK activity during and after HD therapy (p > 0.05). However, HD therapy increased cortisol concentrations after HD therapy (p = 0.034). This study suggests the potential role of intradialytic exercise to prevent the decrease in peripheral frequency of NK cell subsets during HD therapy. Moreover, moderate intensity intradialytic exercise did not exacerbate the systemic inflammation or induce muscle damage during HD therapy.