SP565A SIX-MONTH INTRADIALYTIC EXERCISE PROGRAMME HAS ANTI-INFLAMMATORY EFFECTS ON CIRCULATING MONOCYTE PHENOTYPES AND REGULATORY T CELLS BUT NOT ON CYTOKINE CONCENTRATION

Abstract

Introduction and Aims: Haemodialysis (HD) patients have a dysfunctional and chronically activated immune system that manifests itself with elevated levels of circulating markers of inflammation, altered leucocyte populations and phenotypes, and anergy to antigen challenge. Evidence from observational studies and other populations suggest that regular exercise may have beneficial anti-inflammatory effects, but this is unclear in HD patients. This study aimed to assess the effect of 6 months of regular intradialytic exercise on circulating markers of inflammation, and pro-inflammatory and anti-inflammatory leucocyte phenotypes. Methods: HD patients were recruited from 2 HD units, 22 from a unit where exercise was offered during HD and 16 from a non-exercising control HD unit. Exercising patients were encouraged to exercise during HD up to 3x per week and to aim for 30 min of cycling at an RPE of “somewhat hard”. Blood samples were taken prior to HD at baseline and after 3 and 6 months of regular exercise. Plasma CRP, IL-6 and TNF-α were measured via ELISA, the numbers and proportions of monocyte phenotypes and regulatory T cells (Tregs; CD4+CD25+CD127low/-) were measured via flow cytometry. Physical function was assessed at baseline and after 6 months using the sit-to-stand (STS) 60 test. Results: Sixteen exercise (57.0 ± 10.5 y) and 15 control (70.2 ± 13.7 y) patients completed the 6-month study period. Six months of regular intradialytic exercise significantly improved STS 60 score in the exercise group (13 ± 10 to 24 ± 6 reps; P < 0.001) with no change in the control group. Training had no significant effect on circulating CRP, IL-6 or TNF-α (P ≥ 0.411). The exercise group had a significant decline in the proportion of monocytes that were the pro-inflammatory intermediate phenotype (CD14++CD16+) compared with the usual care group (7.72 ± 1.70 to 6.61 ± 1.74 % vs. 6.90 ± 1.56 to 7.82 ± 1.81 %; P = 0.020). Further, the number of the anti-inflammatory Tregs was enhanced after 6 months in the exercise group compared with usual care (28.1 ± 17.1 to 36.2 ± 17.3 cells•μL-1 vs. 28.7 ± 13.2 to 22.4 ± 10.7 cells•μL-1; interaction: P = 0.009); however, this may be explained by a greater number of total CD4+ lymphocytes compared with control (P = 0.001). Conclusions: High levels of inter- and intra-individual variation may preclude the use of circulating cytokines in the detection of exercise training induced adaptations; this may explain the mixed findings in the literature. The present findings suggest that regular exercise has an anti-inflammatory effect at a circulating cellular level and therefore may be protective against the increased risk of CVD and mortality that is associated with chronic inflammation and elevated numbers of intermediate monocytes.