title: Potential identification of a claudicant group vulnerable to acute kidney injury.
abstract: This observational study aimed to investigate the relationship between renal injury, endothelial function and oxidative stress in claudicants undergoing maximal treadmill exercise. Twenty patients with claudication were identified in whom the urinary N-acetyl-β-D-glucosaminidase (β-NAG)/creatinine ratio, plasma oxidative state and endothelial function were tested pre- and post-maximal treadmill walking exercise. Of the 20 participants in this study, the urinary NAG/creatinine (Cr) rose from a pre-exercise level of 8.9, 6.7 to 14.3 (μmol/L/mmol Cr; median, IQR) to 12.9, 9.1 to 17.7 post exercise (p = 0.0003, Mann Whitney U test). Of the 20 participants, eight participants had a rise of the NAG/Cr ratio post exercise whereas 12 did not. Participants with a rise in the NAG/Cr ratio post exercise had a greater ability to increase endothelial reactivity (%; median, IQR; 2.56, 0.1 to 3.7) cf. (0.1, -4.8 to 0.9, p = 0.03); they also walked further (metres; median, IQR; 415, 208 to 908) cf. (170, 100 to 315, p = 0.04), had a lower pre-exercise H2O2 (median, IQR; 1.9, 1.4 to 2.3 cf. 2.7, 2.1 to 3.3; p = 0.04) and a greater rise in H2O2 post exercise (18.8, -1.5 to 129.7 cf., -7.7, -13.9 to -2.0, p = 0.04). The mechanism by which the phenotypically distinct sub-group of patients with intermittent claudication who experience a NAG/Cr rise involves complex interactions between systemic oxidative stress and endothelial function. Implications on cardiovascular risk in this group requires further investigation.
authors.affiliation: Department of Vascular Surgery, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0HS, UK usman.jaffer@doctors.org.uk.
authors.forename: Usman
authors.initials: U
authors.lastname: Jaffer
authors.affiliation: Department of Vascular Surgery, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0HS, UK.
authors.forename: Prashant
authors.initials: P
authors.lastname: Singh
authors.affiliation: Department of Vascular Surgery, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0HS, UK.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Aslam
authors.affiliation: Department of Vascular Surgery, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0HS, UK.
authors.forename: Frederick Wai Keung
authors.initials: FW
authors.lastname: IITam
authors.affiliation: Department of Vascular Surgery, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0HS, UK.
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Standfield
mesh_terms: D000118:Acetylglucosaminidase / Q000652:urine; D058186:Acute Kidney Injury / Q000097:blood / Q000209:etiology* / Q000378:metabolism / Q000652:urine*; D000368:Aged; D000369:Aged, 80 and over; D003404:Creatinine / Q000652:urine; D004727:Endothelium / Q000378:metabolism; D015444:Exercise; D005260:Female; D006801:Humans; D007383:Intermittent Claudication / Q000097:blood / Q000150:complications* / Q000378:metabolism / Q000652:urine*; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D012307:Risk Factors
chemical_list: D003404:Creatinine; D000118:Acetylglucosaminidase
keywords: endothelial function; kidney; oxidative stress; peripheral vascular disease