Urinary N‐acetyl‐beta‐D‐glucosaminidase excretion in term and preterm neonates

Abstract

Urinary N-acetyl-beta-D-glucosaminidase (NAG) excretion was measured in term and preterm neonates on days 1, 4, 7, 14 and 28 of life. Urinary NAG showed a peak level on day 4 or 7 in these infants. In addition, it tended to be higher with the degree of prematurity. In sick preterms who were depressed at birth and had respiratory failure, the NAG activity was further elevated during the first 2 weeks, suggesting the presence of renal tubular injury in this period. These observations thus suggest that urinary NAG may be a sensitive measure of renal maturation or damage in neonates.

The Diagnostic Role of Urinary N-Acetyl-β-D-glucosaminidase (NAG) Activity in the Detection of Renal Tubular Impairment

“…High levels of urinary NAG have been reported in neonates with perinatal asphyxia (89) and in premature infants where it tended to be higher with the degree of prematurity, and in term and preterm neonates with renal tubular injury (34,79). The level of inflammatory cytokines in urine was elevated together with NAG (20).…”

Evaluation of Renal Functions in Preterm Infants With Respiratory Distress Syndrome

“…Several other markers have also been used to investigate tubular cell damage in infants. The best‐known markers are low molecular weight proteins such as α 1 ‐microglobulin and beta‐2‐microglobulin (B2‐MG; ) and cellular enzymes such as N ‐acetyl‐β‐ d ‐glucosaminidase (NAG; ). Unfortunately, most of these markers mainly reflect proximal tubular cell damage.…”

“…The aim of the present study was to evaluate urinary excretion of π isoenzyme of GST and to understand its relationship with the other urinary markers and with RDS in preterm infants. Our study measured four urinary markers: GST‐π (a marker of distal tubular damage, ) and NAG (a marker of proximal tubular damage, ). Proximal tubular reabsorption was investigated by assessing urinary B2‐MG , and distal tubular reabsorption capacity was investigated by fractional excretion of sodium (FENa, ).…”

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

“…Thus far, several markers have been used to study tubular cell damage in neonates. The best known are low molecular weight proteins such as α 1 ‐microglobulin and β 2 ‐microglobulin 9,10 , and cellular enzymes such as N‐acetyl‐β‐glucosaminidase (NAG) 11 . Unfortunately, most of these markers mainly reflect proximal tubular cell damage.…”

“…The present study is intended to evaluate urinary excretion of π isoenzyme of GST and its relationship to the other renal markers and to the status of oxidative stress in preterm neonates. This study measured four urinary markers: GST‐π (a marker of distal tubular damage), NAG (a marker of proximal tubular damage) 11 , albumin (a marker of glomerular damage) 10 , and 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG) (a marker of oxidative stress) 12–14 .…”