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Renal Biopsy Samples (renal + biopsy_sample)
Selected AbstractsRelevance of insulin-like growth factor 2 in the etiopathophysiology of diabetic nephropathy: Possible roles of phosphatase and tensin homolog on chromosome 10 and secreted protein acidic and rich in cysteine as regulators of repairJOURNAL OF DIABETES, Issue 2 2009Movva SIREESHA Abstract Background: Diabetic nephropathy (DN) is a devastating complication of diabetes, the exact molecular pathophysiology of which is not well established. Hyperglycemia increases insulin-like growth factors (IGFs), especially IGF2, which acts via the IGF1 receptor present on renal cells. Elevated glucose levels damage the kidney, which is repaired by modulators such as secreted protein acidic and rich in cysteine (SPARC). Hence, it was hypothesized that IGF2 and SPARC may have an important role in the etiology of DN. Methods: Human renal biopsies, histopathologically categorized as normal, early Type 2 diabetes mellitus (T2DM), or established DN, were analyzed for the localization and expression of IGF2, its negative regulator phosphatase and tensin homolog on chromosome 10 (PTEN), and SPARC. Results: Expression of IGF2, PTEN, and SPARC was increased in renal biopsies from T2DM patients compared with normal samples. Although IGF2 protein was increased in biopsies from DN patients, PTEN and SPARC levels were decreased. Real-time reverse transcription,polymerase chain reaction indicated that transcript levels of IGF2 and PTEN were greater than those of ,-actin in all human renal biopsy samples. Conclusion: The results suggest the following molecular etiopathophysiology of DN: (i) hyperglycemia upregulates IGF2, which initiates PTEN, a regulator of IGF2 signaling; (ii) loss of this IGF2,PTEN feedback loop causes changes that are characteristic of DN; and (iii) lowered expression of the repair modulator SPARC results in the development and/or progression of DN. Hence, targeting relevant modulators, such as like IGF2, PTEN, and SPARC, may be important in the management of DN. [source] Anti-DNA antibody induction of protein kinase C phosphorylation and fibronectin synthesis in human and murine lupus and the effect of mycophenolic acidARTHRITIS & RHEUMATISM, Issue 7 2009Susan Yung Objective To examine fibronectin (FN) expression in human lupus nephritis and the effect of anti-DNA antibodies on transforming growth factor ,1 (TGF,1) and FN synthesis in cultured human mesangial cells. The effects of mycophenolic acid (MPA) on this pathway, and the effects of mycophenolate mofetil (MMF) treatment in (NZB × NZW)F1/J mice were also studied. Methods Immunohistochemical analyses of renal biopsy samples from patients with active diffuse proliferative lupus nephritis were performed. Cultured human mesangial cells were incubated with human polyclonal anti-DNA antibodies, with or without MPA. (NZB × NZW)F1/J mice with active nephritis were randomized to receive either MMF (100 mg/kg/day) or vehicle treatment for 12 weeks. Results Glomerular FN expression was increased in patients with lupus nephritis, and it colocalized with IgG deposition. Anti-DNA antibodies induced protein kinase C, (PKC,), PKC,I, and PKC,II activation, increased levels of bioactive TGF,1, and increased FN synthesis in human mesangial cells (P < 0.001 for each comparison versus control conditions). Pretreatment of anti-DNA antibodies with exogenous DNA reduced their cellular binding and abrogated their induction of TGF,1 and FN synthesis. Inhibition of PKC activation in human mesangial cells prior to anti-DNA antibody stimulation had no effect on cell proliferation, but resulted in significantly reduced antibody-mediated TGF,1 secretion and FN synthesis. MPA treatment down-regulated PKC,, PKC,I, and PKC,II phosphorylation, reduced levels of TGF,1 bioactivation, and decreased FN synthesis and deposition into the extracellular matrix. MMF treatment in (NZB × NZW)F1/J mice resulted in a reduction in glomerular IgG deposition, PKC activation, and FN expression, as well as an amelioration of proteinuria. Conclusion Human polyclonal anti-DNA antibodies induce TGF,1 and FN synthesis in human mesangial cells through PKC activation, which is inhibited by MPA. [source] Genetic, immunologic, and immunohistochemical analysis of the programmed death 1/programmed death ligand 1 pathway in human systemic lupus erythematosusARTHRITIS & RHEUMATISM, Issue 1 2009George K. Bertsias Objective A putative regulatory intronic polymorphism (PD1.3) in the programmed death 1 (PD-1) gene, a negative regulator of T cells involved in peripheral tolerance, is associated with increased risk for systemic lupus erythematosus (SLE). We undertook this study to determine the expression and function of PD-1 in SLE patients. Methods We genotyped 289 SLE patients and 256 matched healthy controls for PD1.3 by polymerase chain reaction,restriction fragment length polymorphism analysis. Expression of PD-1 and its ligand, PDL-1, was determined in peripheral blood lymphocytes and in renal biopsy samples by flow cytometry and immunohistochemistry. A crosslinker of PD-1 was used to assess its effects on anti-CD3/anti-CD28,induced T cell proliferation and cytokine production. Results SLE patients had an increased frequency of the PD1.3 polymorphism (30.1%, versus 18.4% in controls; P = 0.006), with the risk A allele conferring decreased transcriptional activity in transfected Jurkat cells. Patients homozygous for PD1.3,but not patients heterozygous for PD1.3,had reduced basal and induced PD-1 expression on activated CD4+ T cells. In autologous mixed lymphocyte reactions (AMLRs), SLE patients had defective PD-1 induction on activated CD4+ cells; abnormalities were more pronounced among homozygotes. PD-1 was detected within the glomeruli and renal tubules of lupus nephritis patients, while PDL-1 was expressed by the renal tubules of both patients and controls. PD-1 crosslinking suppressed proliferation and cytokine production in both normal and lupus T cells; addition of serum from patients with active SLE significantly ameliorated this effect on proliferation. Conclusion SLE patients display aberrant expression and function of PD-1 attributed to both direct and indirect effects. The expression of PD-1/PDL-1 in renal tissue and during AMLRs suggests an important role in regulating peripheral T cell tolerance. [source] Chimerism occurs twice as often in lupus nephritis as in normal kidneysARTHRITIS & RHEUMATISM, Issue 9 2006Idske C. L. Kremer Hovinga Objective Systemic lupus erythematosus (SLE) is an immune-mediated disease that particularly affects the kidneys, causing lupus nephritis. In experimental mouse models, lupus nephritis can be mimicked by inducing a chimeric state through the injection of parental T cells in offspring. In humans, pregnancy-induced chimerism may play a role in the pathogenesis of autoimmune diseases such as SLE, but it is likely that only certain chimeric cells have pathogenic potential. In this study, we investigated whether the distribution of chimeric cells is different in the kidneys of women with SLE from that in normal kidneys, and we examined the phenotype of chimeric cells in women with SLE. Methods The presence of chimeric cells was investigated by in situ hybridization targeting the Y chromosome in 57 renal biopsy samples from 49 women with lupus nephritis. Fifty-one kidney autopsy specimens without histomorphologic lesions served as controls. Double-staining for the Y chromosome in combination with CD3 and CD34 markers was performed in 5 kidney specimens with lupus nephritis to identify the phenotype of the chimeric cells. Results Y chromosome,positive cells were found in 27 of 49 patients with lupus nephritis and in 13 of 51 normal controls (P < 0.01). Both CD3+ and CD34+ chimeric cells were identified in lupus nephritis kidney specimens. Conclusion Chimeric cells are present significantly more often in kidneys with lupus nephritis than in normal kidneys, and some of these chimeric cells are T cells. This finding is interesting in light of experimental models demonstrating that lupus nephritis is initiated by chimeric T cells. [source] | ||||||||||