Exercise capacity in polycystic kidney disease.

ABSTRACT

BACKGROUND: Reports about exercise performance in autosomal dominant polycystic kidney disease (ADPKD) are scarce. We aimed to evaluate exercise capacity and levels of nitric oxide and asymmetric dimethylarginine (ADMA) in normotensive patients with ADPKD. STUDY DESIGN: Prospective controlled cohort study. SETTING & PARTICIPANTS: 26 patients with ADPKD and 30 non-ADPKD control participants (estimated glomerular filtration rate>60 mL/min/1.73 m2, aged 19-39 years, and blood pressure [BP]<140/85 mmHg). We excluded smokers, obese people, and individuals with associated diseases. PREDICTOR ADPKD versus control. OUTCOMES: Exercise capacity and nitric oxide and ADMA levels in response to exercise. MEASUREMENTS Cardiopulmonary exercise testing and serum and urinary nitric oxide, plasma ADMA, and BP levels before and after exercise. RESULTS: Mean basal systolic and diastolic BP, estimated glomerular filtration rate, and age did not differ between the ADPKD and control groups (116±12 vs. 110±11 mmHg, 76±11 vs 71±9 mmHg, 113±17 vs. 112±9.6 mL/min/1.73 m2, and 30±8 vs. 28.9±7.3 years, respectively). Peak oxygen uptake and anaerobic threshold were significantly lower in the ADPKD group than in controls (22.2±3.3 vs. 31±4.8 mL/kg/min [P<0.001] and 743.6±221 vs. 957.4±301 L/min [P=0.01], respectively). Postexercise serum and urinary nitric oxide levels in patients with ADPKD were not significantly different from baseline (45±5.1 vs. 48.3±4.6 µmol/L and 34.7±6.5 vs. 39.8±6.8 µmol/mg of creatinine, respectively), contrasting with increased postexercise values in controls (63.1±1.9 vs. 53.9±3.1 µmol/L [P=0.01] and 61.4±10.6 vs. 38.7±5.6 µmol/mg of creatinine [P=0.01], respectively). Similarly, whereas postexercise ADMA level did not change in the ADPKD group compared to those at rest (0.47±0.04 vs. 0.45±0.02 µmol/L [P=0.6]), it decreased in controls (0.39±0.02 vs. 0.47±0.02 µmol/L [P=0.006]), as expected. A negative correlation between nitric oxide and ADMA levels after exercise was found in only the control group (r = -0.60; P<0.01). LIMITATIONS: Absence of measurements of flow-mediated dilatation and oxidative status. CONCLUSIONS: We found lower aerobic capacity in young normotensive patients with ADPKD with preserved kidney function and inadequate responses of nitric oxide and ADMA levels to acute exercise, suggesting the presence of early endothelial dysfunction in this disease.