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Keywords:

  • C-reactive protein;
  • haemodialysis;
  • inflammation;
  • insulin;
  • oxidative stress

ABSTRACT

Aim:  A pilot study to investigate the anti-inflammatory effect of insulin in patients on maintenance haemodialysis.

Background:  Elevated concentrations of pro-inflammatory and oxidative mediators are thought to contribute to the increased cardiovascular risk in haemodialysis. Insulin has been demonstrated to have anti-inflammatory properties and a continuous low-dose insulin infusion in critically ill patients is associated with improved outcomes. The anti-inflammatory effects of insulin in haemodialysis have not been investigated.

Methods:  In a single-blind cross-over study, 11 stable, non-diabetic, haemodialysis patients received a continuous insulin infusion (Actrapid 2 IU/h) during a dialysis of 4 h or a conventional dialysis in random order. Normoglycaemia was maintained by a modified glucose dialysate and glucose infusion. Blood samples were collected at baseline, 1, 4, 6 and 24 h. C-reactive protein (CRP), tumour necrosis factor-α, interleukin-6, neopterin, vascular cell adhesion molecule 1, protein thiols, dityrosine and peroxides were measured.

Results:  Insulin produced a significant reduction in median CRP over the immediate dialysis phase (confidence interval) by 6% (2–9% (95% CI), P = 0.006) and an even greater decline at 24 h (19% (8–28%, 95% CI), P = 0.001) compared with values of the conventional dialysis. No significant changes were observed in the other markers. Median glucose levels were comparable during both dialysis sessions.

Conclusions:  During haemodialysis, insulin may have a modest anti-inflammatory effect as evident by a reduction in CRP that appears to have a persistent effect over the next 24 h post dialysis. More studies are required to examine longer-term benefits as well as the potential role in more high-risk individuals.