P1454CIRCULATING ENDOTOXIN AND MARKERS OF INFLAMMATION: ASSOCIATES WITH PHYSICAL ACTIVITY AND THE EFFECT OF A SIX MONTH PROGRAMME OF CYCLING DURING DIALYSIS (INTRADIALYTIC CYCLING)

Background and Aims Individuals with end-stage kidney disease receiving haemodialysis have elevated levels of circulating endotoxin as a result of changes to the intestinal barrier. These elevated levels are believed to play a role in the high levels of inflammation in this population. Programmes of cycling during dialysis (Intradialytic cycling (IDC)) can provide benefits to individuals receiving haemodialysis, but it is unclear how they may effect circulating levels of endotoxin. Therefore, the primary aim of this study is to investigate the effect of a 6-month programme of IDC on circulating endotoxin. Further aims are to investigate the associations between levels of physical activity and levels of circulating endotoxin and markers of inflammation in haemodialysis patients. Method This is a secondary analysis of the CYCLE-HD randomised controlled trial (ISRCTN11299707). Participants were randomised to either a 6-month programme of IDC (thrice weekly, moderate intensity cycling at RPE 12-14) in addition to usual care (n=46), or usual care (n=46) only. At baseline and 6 months blood samples were collected from the arterial needle immediately prior to haemodialysis therapy and following centrifugation stored at -80°C. Endotoxin, interleukin (IL)-6, IL-10, tumour necrosis factor-α (TNF-α) and high sensitivity C-reactive protein (Hs-CRP) were quantified using immunoassays. Levels of physical activity were measured using an accelerometer. Participants were instructed to wear the accelerometer for 7 days at baseline, and steps per day were calculated by dividing total steps by number of days worn . Results Steps per day data and endotoxin and inflammatory data was available for n=81 participants at baseline. There was a significant negative association between number of steps per day and IL-6 (P=0.001, R=-0.361), Hs-CRP (P<0.0001, R=-0.450) and Endotoxin (P=0.032, R=-0.238) levels. The effect of a 6-month programme of IDC on endotoxin levels and the inflammatory markers are presented in Table 1. Conclusion Higher levels of physical activity were associated with lower levels of circulating endotoxin, IL-6 and Hs-CRP in individuals receiving haemodialysis. A 6-month programme of IDC did not result in increases in circulating endotoxin, indicating that this physiological stress does not result in changes to the intestinal barrier in haemodialysis patients. Lastly, IDC did not appear to increase circulating markers of inflammation.