Biopsy-proven Minimal Change Disease Research Articles

Toll-like receptor 3 ligand, polyIC, induces proteinuria and glomerular CD80, and increases urinary CD80 in mice

We have reported that children with biopsy-proven minimal change disease (MCD) express CD80 (also known as B7.1) in their podocytes and excrete high levels of CD80 in their urine during active nephrotic syndrome. We also reported that polyIC, a Toll-like receptor 3 ligand, increases CD80 mRNA and protein expression in cultured human podocytes dose-dependently, with actin re-organization and a reduction in synaptopodin expression. To determine the effect of polyIC in the kidney, we subjected mice to systemic injection of polyIC or phosphate buffered saline. Mice injected with polyIC developed significant proteinuria with increased urinary CD80 excretion. Glomeruli from mice injected with polyIC were normal by light microscopic examination, but showed increased CD80 production in podocytes by immunofluorescence staining. In isolated glomeruli from mice injected with polyIC, expressions of CD80 and interleukin 10 significantly increased with a mild non-significant increase in CTLA-4, and synaptopodin expression decreased significantly. Our study demonstrates that systemically administered polyIC can induce transient proteinuria and urinary CD80 excretion with an increase in CD80 production in podocytes, increased glomerular CD80 and reduced synaptopodin expression. These findings may be relevant to the pathogenesis of proteinuria in MCD.

Minimal change disease: a variant of lupus nephritis

Some patients with systemic lupus erythematosus (SLE) present with nephrotic syndrome due to minimal change disease (MCD). Histopathological diagnosis of patients with SLE and nephrotic-range proteinuria has shown that these patients present with diffuse proliferative glomerulonephritis and membranous glomerulonephritis, World Health Organization (WHO) classes IV and V, respectively, more frequently than the other classes. In the present study, we reported a case of nephrotic syndrome and renal biopsy-proven MCD associated with SLE. A complete remission occurred after steroid treatment, which was followed by a relapse 15 months later with a concomitant reactivation of SLE. A second biopsy showed WHO class IIb lupus nephritis. Prednisone treatment was restarted, and the patient went into complete remission again. The association of MCD and SLE may not be a coincidence, and MCD should be considered as an associated SLE nephropathy.

A Molecular Profile of Focal Segmental Glomerulosclerosis from Formalin-Fixed, Paraffin-Embedded Tissue

Focal segmental glomerulosclerosis (FSGS) is a common form of idiopathic nephrotic syndrome defined by the characteristic lesions of focal glomerular sclerosis and foot process effacement; however, its etiology and pathogenesis are unknown. We used mRNA isolated from laser-captured glomeruli from archived formalin-fixed, paraffin-embedded renal biopsies, until recently considered an unsuitable source of mRNA for microarray analysis, to investigate the glomerular gene expression profiles of patients with primary classic FSGS, collapsing FSGS (COLL), minimal change disease (MCD), and normal controls (Normal). Amplified mRNA was hybridized to an Affymetrix Human X3P array. Unsupervised (unbiased) hierarchical clustering revealed two distinct clusters delineating FSGS and COLL from Normal and MCD. Class comparison analysis of FSGS + COLL combined versus Normal + MCD revealed 316 significantly differentially regulated genes (134 up-regulated, 182 down-regulated). Among the differentially regulated genes were those known to be part of the slit diaphragm junctional complex and those previously described in the dysregulated podocyte phenotype. Analysis based on Gene Ontology categories revealed overrepresented biological processes of development, differentiation and morphogenesis, cell motility and migration, cytoskeleton organization, and signal transduction. Transcription factors associated with developmental processes were heavily overrepresented, indicating the importance of reactivation of developmental programs in the pathogenesis of FSGS. Our findings reveal novel insights into the molecular pathogenesis of glomerular injury and structural degeneration in FSGS.

Urinary CD80 is elevated in minimal change disease but not in focal segmental glomerulosclerosis

Controversy exists as to whether minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) represent different diseases or are manifestations within the same disease spectrum. Urinary excretion of CD80 (also known as B7.1) is elevated in patients with MCD and hence we tested whether urinary CD80 excretion might distinguish between patients with MCD from those with FSGS. Urinary CD80 was measured in 17 patients with biopsy-proven MCD and 22 with proven FSGS using a commercially available enzyme-linked immunosorbent assay and its molecular size determined by western blot analysis. A significant increase in urinary CD80, normalized to urinary creatinine, was found in patients with MCD in relapse compared to those in remission or those with FSGS. No significant differences were seen when CD80 urinary excretion from MCD patients in remission were compared to those with FSGS. In seven of eight MCD patients in relapse, CD80 was found in glomeruli by immunohistochemical analysis of their biopsy specimen. No CD80 was found in glomeruli of two patients with FSGS and another MCD patient in remission. Thus, our study supports the hypothesis that MCD and FSGS represent two different diseases rather than a continuum of one disease. Urinary CD80 excretion may be a useful marker to differentiate between MCD and FSGS.

C1-C2 point monitoring of low-dose cyclosporin A given as a single daily dose in children with steroid-dependent relapsing nephrotic syndrome

It has been reported that the pharmacokinetics of cyclosporin A (CsA) in children is different from that in adults. It appears that, in general, pediatric patients metabolize CsA more rapidly than adult patients, necessitating the use of higher dose of the drug in pediatric transplant recipients. In this context, we speculated that single-dose daily administration of low-dose CsA may be associated with a higher peak blood level without associated trough blood level elevation, and thereby yield better results and allow safer use of the drug than the conventional twice daily administration dosing used for the treatment of childhood idiopathic nephrotic syndrome (INS). A total of 10 children with steroid-dependent relapsing INS (9 with biopsy-proven minimal-change disease) who showed steroid toxicity were enrolled in the study. The initial daily dose of CsA (Neoral) used was around 2.0 mg/kg, given as a single daily dose before breakfast. The dose was subsequently adjusted to achieve a C1-C2 point blood level between 600 - 800 ng/ml. The dose of the concomitantly administered prednisolone was tapered following the commencement of CsA. The mean daily CsA dosage, the mean C1-C2 point blood level and the mean trough blood level in the subjects were 2.2 +/- 0.8 mg/kg, 754.0 +/- 71.9 ng/ml and 42.7 +/- 29.2 ng/ml, respectively. At the latest observation, after a mean duration of 17 months (6 - 24 months) of CsA therapy, the minimum dose of prednisolone required for maintenance of clinical remission and the calculated relapse rate were significantly decreased as compared to the respective pretreatment values (0.52 +/- 0.46 mg/kg on alternate days, vs. 0.97 +/- 0.63 mg/kg on alternate days, and 0.28 +/- 0.32 times per six months, vs. 1.06 +/- 0.41 times per six months, respectively, p = 0.005). No significant change was observed in the mean estimated GFR value as compared to the pretreatment value (183.1 +/- 35.4 ml/min/1.73 m2vs. 185.4 +/- 39.3 ml/min/1.73 m2). No evidence of CsA nephrotoxicity was observed in a repeat renal biopsy performed around 12 months after the commencement of CsA therapy in two patients. Despite the limitations of the study, our results suggest that administration of low-dose CsA as a single daily dose with C1-C2 point blood level monitoring might be an equally effective and safe and, therefore, more cost-beneficial, protocol for the treatment of steroid-dependent cases of relapsing INS, as conventional twice-daily administration of CsA with trough blood level monitoring. Further studies to confirm the long-term efficacy and safety of this CsA treatment protocol in larger numbers of patients are, however, needed.

Interleukin-8 and Tumor Necrosis Factor-Alpha Are Increased in Minimal Change Disease but Do Not Alter Albumin Permeability

Aims: Minimal change disease (MCD) is the most common primary nephrotic syndrome in children. Some suggested that interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α) are involved in the pathogenesis of MCD. This study was done to see changes of plasma and urinary IL-8, TNF-α, and their effects on determination of permeability of glomerular basement membrane (BM) contributed by heparan sulfate proteoglycan (HSPG). Methods: Study patients consisted of 19 biopsy-proven MCD children aged 2–15 years old. Both plasma, urinary IL-8 and TNF-α were measured. Employing the Millicell system, IL-8 and TNF-α were screened for the permeability factors. We examined whether IL-8 and TNF-α regulated BM HSPG gene expression and HS synthesis in the glomerular epithelial cells (GECs). Results: Urinary IL-8 during relapse was significantly increased when compared with that of during remission or controls (13,996 ± 2,811 vs. 2,941 ± 373, 5,331 ± 640 ng/mg·cr) (p < 0.05). Urinary TNF-α during relapse was also significantly increased (364.4 ± 51.2 vs. 155.3 ± 20.8, 36.0 ± 4.5 ng/mg·cr) (p < 0.05). Plasma IL-8 during relapse was significantly increased compared to that during remission(1.19 ± 0.62 vs. 0.51 ± 0.42 ng/ml) (p < 0.05). However, the negative results were obtained in the permeability assay using the Millicell system. No difference was seen in BM HSPG gene expression and HS synthesis in the GECs. Conclusion: Therefore, it seems that both IL-8 and TNF-α may not play a disease-specific role in the pathogenesis of MCD.