Renal functions in pediatric patients with beta-thalassemia major: relation to chelation therapy: original prospective study

BACKGROUND: In β-thalassemia, profound anemia and severe hemosiderosis cause functional and physiological abnormalities in various organ systems. In recent years, there have been few published studies mainly in adult demonstrating renal involvement in β-thalassemia. This prospective study was aimed to investigate renal involvement in pediatric patients with transfusion dependant beta-thalassemia major (TD-βTM), using both conventional and early markers of glomerular and tubular dysfunctions, and to correlate findings to oxidative stress and iron chelation therapy. METHODS: Sixty-nine TD-βTM patients (aged 1-16 years) and 15 healthy controls (aged 3-14 years) were enrolled in this study. Based on receiving chelation therapy (deferoxamine, DFO), patients were divided into two groups: group [I] with chelation (n = 34) and group [II] without chelation (n = 35). Levels of creatinine (Cr), calcium (Ca), inorganic phosphorus (PO(4)), uric acid (UA) and albumin were measured by spectrophotometer. Serum (S) levels of cystatin-C (S(CysC)) and total antioxidant capacity (S(TAC)) and urinary (U) levels of β(2)-microglobulin (U(β2MG)) were measured by immunosorbent assay (ELISA). Urinary N-acetyl-beta-D-glucosaminidase (U(NAG)) activity and malondialdehyde (U(MDA)) were measured by chemical methods. Estimated glomerular filtration rate (eGFR) was determined from serum creatinine. RESULTS: In patient with and without chelation, glomerular [elevated S(CysC), S(Cr), U(albumin)/Cr and diminished eGFR]; and tubular dysfunctions [elevated S(UA), S(PO4), U(NAG)/Cr, U(β2MG)/Cr] and oxidative stress marker disturbances [diminished S(TAC )and elevated U(MDA)/Cr] were reported than controls. In patients with chelation, S(CysC )was significantly higher while, S(TAC )was significantly lower than those without chelation. In all patients, S(CysC )showed significant positive correlation with S(Cr )and negative correlation with eGFR; S(TAC )showed significant positive correlation with eGFR and negative correlation with S(Cys)C, S(Cr), U(NAG)/Cr; U(MDA)/Cr showed significant positive correlation with U(albumin)/Cr, U(β2MG)/Cr, U(NAG)/Cr. CONCLUSIONS: Our data confirm high frequency of glomerular and tubular dysfunctions in TD-βTM pediatric patients which could be attributed to oxidative stress and DFO therapy.