Vascular surgical society of great britain and ireland: systemic effects of exercise in claudicants are associated with neutrophil activation
BACKGROUND: Claudication induces potentially harmful systemic effects which may be mediated through free radicals and neutrophil activation. This study examined the impact of these mechanisms on renal tubular function. METHODS: Flow cytometry was used to determine CD11b expression by neutrophils and monocytes, and expression of P selectin (CD62P) by platelets, in 16 patients with intermittent claudication and eight matched controls before and at intervals after exercise. Total antioxidant capacity (TAC) and von Willebrand factor (vWF) were measured at similar intervals. Renal tubular function was assessed before and 60 min after exercise by assay of retinol binding protein : creatinine ratio (RBP : Cr) in urine. All patients and none of the controls had a significant exercise-induced fall in ankle pressure. Fluorescein isothiocyanate-labelled monoclonal antibodies against CD11b and CD62P were added to blood and analysis was performed on the flow cytometer within 72 h. RESULTS: There were no significant differences in monocytes, platelets or vWF between patients and controls over time. There was a significant change in RBP : Cr following exercise in patients (median 4.2 (95 per cent confidence interval 2.4-85.2); P </= 0.01, Wilcoxon test) but not controls (2.7 (-1 to 7.5); P not significant). See Table above. CONCLUSION: Renal tubular function was adversely affected by acute exercise in claudicants. TAC was higher in claudicants at rest and was increased after exercise suggesting an increased free radical challenge. Neutrophil activation is significantly different between claudicants and controls before and after exercise, and may provide a link between free radical generation and renal tubular injury.
Lewis
DR
Bristol Royal Infirmary, Bristol, UK.
Day
A
Jeremy
JY
Newcombe
PV
Brookes
ST
Baird
R
Smith
FC
Lamont
PM