Importance of Evaluation of Urinary Iron and Transferrin in the Common Histopathological Types of Idiopathic Nephrotic Syndrome in Children

Nephrosis with minimal glomerular changes, minimal change nephrotic syndrome
(MCNS) and focal-segmental glomerulosclerosis (FSGS) are by far the predominant
causes of idiopathic nephrotic syndrome (INS). Recently there is an increasing
interest in the role of iron in the causation of renal injury and deterioration of renal
function in adults and children with nephrotic syndrome. Urinary excretion of N-acetyl--D-glucosaminidase (NAG) may be useful as a marker of tubular dysfunction
and damage in idiopathic nephrotic syndrome (INS) which often characterizes
steroid-resistant children. The present studywas carried out to estimate the level of
serum and urinary iron and transferrin to evaluate the effect of their excretion in the
development of anemia in nephrotic children,also to clarify the prognostic value of
urinary iron according to the histopathological type of the disease. The present work
was also devoted to assess the role of immune system in the pathogenesis of
idiopathic nephrotic syndrome by determination of serum 2-microglobulin and
serum and urinary neopterin. The degree of tubular damage in the most common
histopathological types of idiopathic nephrotic syndrome was assessed by estimation
of urinary N-acetyl--D-glucosaminidase enzyme (NAG). The study was conducted on
45 children who were grouped as control group and nephrotic children group which
was subdivided into two subgroups: minimal-change nephrotic syndrome (MCNS)
group and segmental glomerulosclerosis (FSGS) group. The study included fifteen in
each group with no significant difference inthe mean age and sex between the three
studied groups. All children in the study were subjected to thorough history taking,
complete physical examination and laboratory investigations which included serum
and urinary iron excretion per 24 hours, serum and urinary transferrin excretion per
24 hours, serum ferritin, total iron binding capacity, serum and urinary neopterin
excretion per 24 hours, serum 2-microglobulin, urinary N-acetyl--D-glucosaminidase enzyme (NAG) excretion per 24 hours, stool analysis for occult
blood to exclude gastrointestinal bleeding and finally renalbiopsy was done for all
nephrotic children enrolled in the study for histopathological examination. The
results of our study showed that idiopathic nephrotic syndrome (INS) is associated
with normocytic normochromic anemia despite the increased urinary losses of iron
and transferrin. Also, the results of this study showed that both serum neopterin and
2-microglobulin were significantly higher inboth nephrotic groups than the control
subjects. Serum neopterin level was significantly higher in FSGS group than MCNS group with no significant difference of serum 2-microglobulin between MCNS and FSGS groups. It could be concluded that estimation of urinary proteins, urinary iron and urinary NAG could be important for follow up and prediction of the prognosis in children with INS.