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Suppressors of Cytokine Signaling (SOCS) inhibit Signal Transducers and Activators of Transcription (STATs) phosphorylation by binding and inhibiting Janus Kinases (JaKs). The aim of the present study was to evaluate the influence of glucocorticosteroids on the JaK/STAT signaling pathway in the leukocytes of nephrotic syndrome (NS) patients. The study group was composed of 34 steroid sensitive NS (SSNS) children and 20 steroid resistant NS (SRNS) subjects. Gene expression was assessed by real-time PCR using pre-designed human JaK/STAT PCR array. Protein expression was evaluated using ELISA assay (plasma concentration) and immunofluorescence (in situ protein expression). In SSNS children, the initial increased expression of JaK1, JaK2, JaK3, STAT1, STAT2, STAT6, TYK2, SOCS1, SOCS2, SOCS3, SOCS4 and SOCS5 was reduced back to the control limits. Similarly, in SRNS patients the increased levels of almost all mRNA expressions for the abovementioned genes were decreased, with the exceptions of SOCS3 and SOCS5 expressions. These mRNA expressions were still significantly increased and correlated with early unfavorable course of nephrotic syndrome in children. Plasma levels of SOCS3, SOCS5, IL-6 and IL-20 were significantly increased in SRNS subjects after six weeks of steroids medication compared to SSNS and control participants. We conclude that SOCS3 and SOCS5 increased mRNA expressions might predict initial resistance to steroids in NS patients. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 4, pp. 719–728)

Idiopathic nephrotic syndrome (INS) in children is most commonly caused by primary glomerulopathies. Morphological lesions observed in INS might be secondary to inflammatory factors of mainly extra-renal origin. The vascular endothelial growth factor (VEGF) family is regarded as playing a crucial role in this pathomechanism. The aim of the present work was to analyze the possible relation between VEGF-C and VEGF receptor (VEGFR)-2 expressions at electron microscopy level in different INS cases. The study group comprised 18 children with minimal change disease (MCD), 30 patients diagnosed with diffuse mesangial proliferation (DMP) and 11 subjects with focal segmental glomerulosclerosis (FSGS). An indirect immunohistochemical assay employing monoclonal anti-VEGF-C and anti-VEGFR-2 antibodies was applied in the study. The immunohistochemical expression of VEGF-C within podocyte cytoplasm was significantly increased in DMP subjects who were resistant to steroids and in all FSGS patients compared to MCD children and controls (p < 0.05). VEGF-C over-expression in these cases was followed by downregulation of VEGFR-2. Nephrotic syndrome progression correlates with the downregulation of podocyte VEGFR-2. For this reason, decreased VEGFR-2 expression in the podocyte processes of children with idiopathic nephrotic syndrome might be regarded as a potent factor of unfavorable prognosis. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 3, pp. 472–478)

BACKGROUNDGalectins 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 METHODSEighteen 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.RESULTSIn 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 (pCONCLUSIONSA 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 extraglomerular galectin-3 immunoreactivity in certain DMP individuals could be regarded as the factor of unfavourable prognosis.

To evaluate the immunohistochemical expression of VEGF-C, CD34 and VEGFR-2 in cancer tissue of children diagnosed with stadium 4 neuroblastoma (NB) and correlate their presence with the survival rate of children diagnosed with that stage of the disease. Eighteen children assigned to stadium 4 composed the study group. Fourteen patients (allocated to stadium 3) formed a control group. VEGF-C, CD34 and VEGFR-2 expressions were evaluated by immunohistochemical assay. Consecutive slides incubated with anti-CD34 and anti-VEGFR-2 antibodies revealed that the two markers were colocalized within endothelial layer of the blood vessels. On the other hand, VEGF-C was expressed exclusively in tumour cells. As demonstrated by Fisher's exact test, the risk of NB treatment failure (progression or relapse) as well as tumour related death, when all the patients were considered, was found to be significant in VEGF-C positive patients. VEGF-C expression in NB constitutes a potent risk factor and may direct future anti-angiogenic treatment strategy. The proximity of VEGF-C and CD34/VEGFR-2 of NB could be the equivalent of a potentially interesting VEGF-C fashion involving a tumour cell invasion into the blood vessels in an early phase of metastases promoting.

The aim of this study was to demonstrate the value of immunocytochemical staining of Ki67 antigen expression in blast cells of children with acute myeloid leukemia (AML) and to evaluate its correlation with treatment failure. The material included bone marrow specimens obtained during induction treatment from 46 children treated for AML between 1998-2003. Immunocytochemical staining for Ki67 was based on the ABC technique. Expression of Ki67 antigen on day 0 of induction treatment was confirmed in all patients. The percentage of immunopositive blasts ranged from 88.4% to 99.8% (mean 91.8%). On day 15, according to chemotherapy response, patients were divided into two groups: G1-36 children who responded to induction treatment and reached remission (blast level 5%, low risk group) and G2-10 patients who did not meet remission criterion (blast level > 5%) and were assigned to the high risk (HR) group. Out of 10 children assigned to this group, Ki67 expression in blast cells was confirmed in 4 cases. The fraction of immunopositive blasts ranged from 78.4% to 88.6%. In the other 6 cases, blasts were Ki67-negative. In 12-month period after beginning the treatment, 18 cases of treatment failure (including 7 deceases) were observed in both groups. Five deaths, observed in the HR group, concerned the patients characterized by Ki67-negative blasts. The results indicate a possible correlation between the Ki67-immunonegative blast pattern on day 15 of treatment induction and early decease of AML children assigned to HR group.