New tubular injury markers in children with a solitary functioning kidney

Abstract

BackgroundThe present study aimed to assess whether the urinary profiles of the lysosomal exoglycosidases N‑acetyl‑β‑hexosaminidase (HEX) and its isoenzymes A (HEX A) and B (HEX B), α-fucosidase (FUC), β-galactosidase (GAL), α-mannosidase (MAN), and β- glucuronidase (GLU) are useful biomarkers of tubular dysfunction in children with a solitary functioning kidney (SFK).MethodsWe measured the urinary activity of HEX, its isoenzymes HEX A, HEX B, and FUC, GAL, MAN, and GLU in 52 patients with SFK. Patients were subdivided into two groups: congenital SFK (cSFK)—unilateral renal agenesis and acquired SFK (aSFK)—unilateral nephrectomy. The reference group (RG) contained 60 healthy sex- and age-matched children.ResultsUrinary activity of all exoglycosidases in SFK was significantly higher than in RG (p < 0.05). There were no differences in exoglycosidase activity between cSFK and aSFK (p > 0.05). HEX and its isoenzymes HEX A and HEX B correlated negatively with estimated glomerular filtration rate (eGFR), and all estimated parameters correlated positively with albumin/creatinine ratio (p < 0.001).ConclusionUrinary activity of HEX, its isoenzymes HEX A and HEX B, and FUC, GAL, MAN, and GLU is elevated in children with SFK. Long-term follow-up studies in larger groups of children with SFK may help us to better understand their clinical significance.

Physiology and Pathophysiology of Compensatory Adaptations of a Solitary Functioning Kidney

“… Gadalean et al (2013) observed that in adult patients with an acquired and congenital SFK there was a ∼52–60% increase in urinary N -acetyl-beta- D -glucosaminidase, a marker of proximal tubule dysfunction. Similarly, in children with both a congenital SFK and acquired SFK, urinary N -acetyl-β-hexosaminidase (HEX), an indicator of proximal tubular damage, was elevated compared with age-matched healthy individuals ( Taranta-Janusz et al, 2014 ). Moreover, estimated urinary HEX was a good diagnostic indicator of kidney injury (presence of albuminuria) in children with a SFK ( Taranta-Janusz et al, 2014 ).…”

Reference Data on Neonatal Serum N-Acetyl-β-hexosaminidase Activity

“…Exoglycosidase activities engaged in glycoconjugate catabolism are utilized in diagnostics of adults [ 10 , 12 ], children [ 15 , 16 ], and neonates [ 13 , 14 , 17 , 18 ]. Deficiencies of N-acetyl- β -hexosaminidase A and B isoenzyme activities in neonatal body are the reason for storing glycoconjugates in their lysosomes that cause Sandhoff and Tay-Sachs diseases [ 11 ].…”

“…HEX high activity in serum reflects high intensity of tissue glycoconjugate degradation caused by the inflammatory conditions and other etiologies [ 12 ]. Increased HEX activity has been found in the urine of neonates with nephrotoxic drug intoxication [ 13 ], fever [ 14 ], and in the urine of children with nephritis [ 15 ] as well as solitary functioning kidney [ 16 ]. Lobe et al [ 17 ] suggested determination of the serum HEX activity for early diagnosis of the necrotizing enterocolitis (NEC) in the premature babies, but Shattuck et al [ 18 ] claim that serum HEX activity concentration is not a good marker for NEC because reference ranges in newborn children have not been properly characterized.…”

Urine exoglycosidases are potential markers of renal tubular injury in children with ureteropelvic junction obstruction

“…Total HEX activity and its isoenzymes have been considered as markers of renal proximal tubular function . Other lysosomal exoglycosidases that have been evaluated in many pathological situations , but not in children with hydronephrosis, include α ‐fucosidase (FUC), which releases fucose from oligosaccharides; β ‐galactosidase (GAL), which releases galactose, α ‐mannosidase (MAN), which releases mannose, and β ‐glucuronidase (GLU), which hydrolyses glucuronides.…”