Urinary C-megalin for screening of renal scarring in children after febrile urinary tract infection

Abstract

BackgroundFebrile urinary tract infection (fUTI) in children may cause renal scarring. This study aimed to investigate the usefulness of urinary biomarkers for diagnosing renal scarring after fUTI.MethodsThirty-seven children (median age: 1.36 years, range: 0.52-12.17 years, 25 boys) with a history of fUTI, who underwent renal scintigraphy for 4 months or longer after the last episode of fUTI, were analyzed. A spot urine sample was obtained on the day of renal scintigraphy to measure levels of total protein, N-acetyl-β-D-glucosaminidase (NAG), β-microglobulin (BMG), neutrophil gelatinase-associated lipocalin (NGAL), liver-type fatty acid binding protein (L-FABP), and C-megalin (full-length megalin). Results were corrected for urinary creatinine (Cr) and compared between the group with renal scarring (n=23) and that without scarring (n=14). Urinary levels of C-megalin were also measured in healthy control subjects.ResultsNo significant differences in total protein, NGAL, L-FABP, NAG, and BMG levels were found between the groups. However, C-megalin levels were significantly higher in the renal scarring group than in the non-renal scarring group and healthy controls (P<0.001). A cutoff value of 6.5 pmol/nmol of urinary C-megalin/Cr yielded 73.9% of specificity and 92.9% of sensitivity.ConclusionUrinary C-megalin is useful for diagnosing renal scarring caused by fUTI.

The role of increased intestinal permeability markers in developing urinary tract infection in children of the first three years of life

“…В нашем исследовании ни у одного ребенка снижения функционального состояния почек выявлено не было, что указывает на необходимость более детального изучения патогенетической значимости данных белков. Так, известно, что белок FABP1 у детей с ИМВП может быть использован в качестве прогностического маркера формирования рубцовых тканей в почечной паренхиме [15,21]. Кроме того, имеются исследования, предлагающие использовать повышенные значения протеина L-FABP в качестве маркера диагностики ПМР [8].…”

Significance of urinary C-megalin excretion in vitamin D metabolism in pre-dialysis CKD patients

“…recently showed that urinary C-megalin excretion is increased via exocytosis from PTECs injured by endo-lysosomal overload caused by megalin-mediated protein metabolism 10 . The clinical significance of urinary C-megalin, which represents “metabolic nephron load,” was confirmed by results showing that it is also a good marker to diagnose pediatric patients with renal scarring, which often occurs following a febrile urinary infection and is often accompanied by residual nephron overload 11 . Therefore, urinary C-megalin excretion likely reflects phenotypic changes that progress in PTECs in CKD patients 12 .…”