Exercise-induced renal tubular injury in intermittent claudication

Abstract

While, exercise in intermittent claudication (IC) may improve symptoms and exercise tolerance, it has been shown to produce an ischemia-reperfusion injury. This study aimed to assess the impact of this on renal function, by measuring the changes in activity of the urinary enzyme N-acetyl-β-D-glucosaminidase (NAG), a sensitive marker of renal tubular damage. 15 patients with IC and 15 controls underwent a standardized exercise treadmill test. Changes in Ankle/Brachial Pressure Index (ABPI) were measured as was the urinary activity of NAG at rest, and following exercise. While a marked change was seen in ABPI's of the IC group, no change was apparent in the controls. Urinary NAG activity rose significantly in the IC group following exercise (mean 51.25 μmol/h/mmol creatinine) compared with both resting levels (30.4) and with the post-exercise NAG of controls (26.4),P < 0.05. There was no significant difference in NAG levels within the control group (23.5 vs 26.4). Exercise in intermittent claudication is associated with a renal tubular cell injury, which may be related to an ischemia-reperfusion injury.