Urinary α- and π-glutathione s-transferases for early detection of acute kidney injury following cardiopulmonary bypass.

CONTEXT: Urinary α-GST and π-GST are renal tubular leakage markers. OBJECTIVE: To evaluate the performance characteristics of these markers for the early detection of acute kidney injury (AKI). MATERIALS AND METHODS: Multicenter prospective cohort study of 252 adults undergoing cardiopulmonary bypass (CPB). RESULTS: AKI developed in 72 patients. The 2 h post-CPB π-GST level modestly predicted the development of AKI, including higher stages of severity, whereas α-GST did not. DISCUSSION: Small number of events and absence of subsequent post-operative biomarker measurements. CONCLUSIONS: Among adults undergoing CPB, urinary π-GST outperformed α-GST for predicting AKI, but neither marker displayed good discrimination.

Polymorphisms in the myeloperoxidase gene locus are associated with acute kidney injury-related outcomes.

Myeloperoxidase (MPO) is a lysosomal enzyme that may be involved in oxidative stress-mediated kidney injury. Using a two-step approach, we measured the association of four polymorphisms across the length of the MPO gene with systemic markers of oxidative stress: plasma MPO and urinary 15-F(2t)-isoprostane levels. Adverse outcomes were measured in a primary cohort of 262 adults hospitalized with acute kidney injury, and a secondary cohort of 277 adults undergoing cardiac surgery with cardiopulmonary bypass and at risk for postoperative acute kidney injury. Dominant and haplotype multivariable logistic regression analyses found a genotype-phenotype association in the primary cohort between rs2243828, rs7208693, rs2071409, and rs2759 MPO polymorphisms and both markers of oxidative stress. In adjusted analyses, all four polymorphic allele groups had 2-3-fold higher odds for composite outcomes of dialysis or in-hospital death or a composite of dialysis, assisted mechanical ventilation, or in-hospital death. The MPO T-G-A-T haplotype copy-number was associated with lower plasma MPO levels and lower adjusted odds for the composite outcomes. Significant but less consistent associations were found in the secondary cohort. In summary, our two-step genetic association study identified several polymorphisms spanning the entire MPO gene locus and a common haplotype marker for patients at risk for acute kidney injury.