Expression of galectin-3 in nephrotic syndrome glomerulopaties in children

Background: Galectins are a family of ancient animal carbohydrate binding proteins; the name is from their description as beta-galactoside-specific lectins. They have been strongly implicated in inflammation and cancer. Studies of the association of galectins with various aspects of kidney disease in humans are still at an early stage. In line with the above, the aim of the present report was to analyse the immunohistochemical expression of galectin-3 (the only chimera galectin currently identified) in renal biopsy specimens of children with idiopathic nephrotic syndrome (INS). Patients and Methods: Eighteen children with minimal change disease (MCD), 30 with diffuse mesangial proliferation (DMP) and 11 with focal segmental glomerulosclerosis (FSGS) treated between 2003 and 2006 in the Department of Paediatric Cardiology and Nephrology, Poznan University of Medical Sciences. An indirect immunohistochemical protocol using a polyclonal rabbit antibody against human galectin-3 was employed. Results: In the control, MCD and DMP children who responded to steroid therapy anti-galectin-3 reactivity was present both in renal cortex and medulla. It was the strongest within cortical collecting ducts and subjectively less expressed in distal tubules. The total number of galectin-3 positive cortical and medullary segments of collecting ducts was significantly higher in the subjects who did not respond to steroid therapy These patients revealed also immunohistochemical reactivity of galectin-3 within nuclei of individual glomerular mesangial cells (p<0,001). Conclusions: A suggested galectin-3 authority in mature human glomeruli during proteinuric glomerulopathies may indicate, on the one hand, its anti-inflammatory effect, but on the other can prognosticate a further glomerular reconstruction leading to FSGS. Taken together, both glomerular and extra-glomerular galectin-3 immunoreactivity in certain DMP individuals could be regarded as the factor of unfavourable prognosis.