Acute intradialytic exercise does not affect the phenotype or pro-thrombotic nature of microparticles but alters their function

Haemodialysis patients have a dysfunctional and activated immune system, with comorbidity-associated risks of thrombosis, cardiovascular disease and infection. Microparticles are biologically active nanovesicles shed from activated cells and are a novel biomarker of inflammation. Exercise is anti-inflammatory and advocated in haemodialaysis, yet the effect on microparticles is unknown. We assessed the acute effect of intradialytic exercise on microparticle number, phenotype, ability to induce endothelial cell reactive oxygen species and activate leukocytes in vitro. 11 patients were studied during a routine haemodialysis session and one where they exercised. Irrespective of exercise microparticle number increased during haemodialysis (2064 to 7071 MP/µl, P<0.001) as did phosphatidylserine+ (P<0.05), platelet-derived (P<0.01) and percentage pro-coagulant neutrophil-derived microparticles (P<0.05) and leukocyte-activating ability (P<0.01). Microparticles collected 0 and 60 min post-exercise induced greater reactive oxygen species generation from cultured endothelial cells than when resting (P<0.05). In summary moderate intensity intradialytic exercise had no effect on the circulating MP response or their leukocyte-activating ability. However, those collected after exercise induced greater reactive oxygen species from endothelial cells, suggesting an acute, transient pro-inflammatory response. This may stimulate a longer lasting anti-inflammatory adaptation which needs to be confirmed