Quantitation of glutathione S transferase-π in the urine of preterm neonates

Background: Glutathione S transferases (GSTs) are widely distributed enzymes found in highly varying amounts in tissues of the human body. The enzyme GST-π in urine has been used as a marker of renal distal tubular cell damage. The present study was intended to evaluate urinary excretion of GST-π and its relationship to other renal markers and to the status of oxidative stress in preterm neonates. Methods: Levels of urinary GST-π, N-acetyl-β-glucosaminidase (a marker of proximal tubular damage), albumin (a marker of glomerular damage) and 8-hydroxy-2′-deoxyguanosine (a marker of oxidative stress) and serum creatinine were measured in preterm neonates at 1 and 4 weeks of age. Results: The results showed that urinary excretion of GST-π is increased in preterm neonates compared with reported values for healthy adults. No significant relationship was detected between urinary GST-π and other markers for renal function. Urinary GST-π showed significantly positive correlation with urinary 8-hydroxy-2′- deoxyguanosine at 1 and 4 weeks. Sick neonates treated with supplemental oxygen and mechanical ventilation showed significantly higher levels of GST-π as well as 8-hydroxy-2′-deoxyguanosine than clinically stable neonates did at 4 weeks. Conclusions: These results indicate the potential effect of systemic oxidative stress on urinary excretion of GST-π. Further studies are necessary to explore the effect of oxidative conditions on expression of GST-π in distal tubules in the human kidney.