Responsiveness of afferent renal nerve units in renovascular hypertension in rats.

Previous data suggest that renal afferent nerve activity is increased in hypertension exerting sympathoexcitatory effects. Hence, we wanted to test the hypothesis that in renovascular hypertension, the activity of dorsal root ganglion (DRG) neurons with afferent projections from the kidneys is augmented depending on the degree of intrarenal inflammation. For comparison, a nonhypertensive model of mesangioproliferative nephritis was investigated. Renovascular hypertension (2-kidney, 1-clip [2K1C]) was induced by unilateral clipping of the left renal artery and mesangioproliferative glomerulonephritis (anti-Thy1.1) by IV injection of a 1.75-mg/kg BW OX-7 antibody. Neuronal labeling (dicarbocyanine dye [DiI]) in all rats allowed identification of renal afferent dorsal root ganglion (DRG) neurons. A current clamp was used to characterize neurons as tonic (sustained action potential [AP] firing) or phasic (1-4 AP) upon stimulation by current injection. All kidneys were investigated using standard morphological techniques. DRG neurons exhibited less often tonic response if in vivo axonal input from clipped kidneys was received (30.4% vs. 61.2% control, p < 0.05). However, if the nerves to the left clipped kidneys were cut 7 days prior to investigation, the number of tonic renal neurons completely recovered to well above control levels. Interestingly, electrophysiological properties of neurons that had in vivo axons from the right non-clipped kidneys were not distinguishable from controls. Renal DRG neurons from nephritic rats also showed less often tonic activity upon current injection (43.4% vs. 64.8% control, p < 0.05). Putative sympathoexcitatory and impaired sympathoinhibitory renal afferent nerve fibers probably contribute to increased sympathetic activity in 2K1C hypertension.

Cold Shock Proteins Mediate GN with Mesangioproliferation.

DNA binding protein A (DbpA) is a member of the human cold shock domain-containing protein superfamily, with known functions in cell proliferation, differentiation, and stress responses. DbpA mediates tight junction-associated activities in tubular epithelial cells, but the function of DbpA in mesangial cells is unknown. Here, we found DbpA protein expression restricted to vascular smooth muscle cells in healthy human kidney tissue but profound induction of DbpA protein expression within the glomerular mesangial compartment in mesangioproliferative nephritis. In vitro, depletion or overexpression of DbpA using lentiviral constructs led to inhibition or promotion, respectively, of mesangial cell proliferation. Because platelet-derived growth factor B (PDGF-B) signaling has a pivotal role in mesangial cell proliferation, we examined the regulatory effect of PDGF-B on DbpA. In vitro studies of human and rat mesangial cells confirmed a stimulatory effect of PDGF-B on DbpA transcript numbers and protein levels. Additional in vivo investigations showed DbpA upregulation in experimental rat anti-Thy1.1 nephritis and murine mesangioproliferative nephritis models. To interfere with PDGF-B signaling, we injected nephritic rats with PDGF-B neutralizing aptamers or the MEK/ERK inhibitor U0126. Both interventions markedly decreased DbpA protein expression. Conversely, continuous PDGF-B infusion in healthy rats induced DbpA expression predominantly within the mesangial compartment. Taken together, these results indicate that DbpA is a novel target of PDGF-B signaling and a key mediator of mesangial cell proliferation.

A novel CRIg-targeted complement inhibitor protects cells from complement damage.

The inappropriate activation of complement may contribute to various immune diseases. The alternative pathway (AP) predominates during complement activation regardless of the initiating pathways. Hence, the main AP regulator factor H (FH) holds great potential as an attractive therapeutic intervention. In addition, complement receptor of the immunoglobulin superfamily (CRIg) has been demonstrated to inhibit AP and, more notably, still specifically binds to C3b/iC3b. We thus developed novel CRIg-targeted complement inhibitors by connecting the functional domains of CRIg and FH, which we termed CRIg-FH and CRIg-L-FH. CRIg-L-FH, slightly more potent than CRIg-FH, considerably inhibited both AP- and also classical pathway (CP)-mediated hemolysis and successfully eliminated the deposition of C3b/iC3b. Kinetic analysis further revealed that the binding affinity constant (KD) of CRIg/FH was in the micromolar range, consistent with its long-lasting binding to complement-attacked cells. CRIg-L-FH efficiently protected aberrant erythrocytes of patients with paroxysmal nocturnal hemoglobinuria (PNH) from AP- and CP-mediated complement damage (IC50 was 22.43 and 64.69 nM, respectively). Moreover, CRIg-L-FH was found to inhibit complement activation induced by the anti-Thy1 antibody in a mesangioproliferative glomerulonephritis (MPGN) rat model. Hence, CRIg-L-FH protects glomerular mesangial cells (GMCs) from complement-mediated injury and proliferative lesions. These findings strongly suggest that CRIg/FH is a potential therapeutic drug candidate for a range of complement-mediated diseases.

The Effects of Perilla frutescens Extracts on IgA Nephropathy: A Systematic Review and Meta-Analysis.

(1) Background: Chronic renal disorders (CRD) are associated with significant comorbidities and necessitate complex therapeutic management. As time passed, Perilla frutescens (PF) became a promising therapeutic option for CRD. The aim of this systematic review and meta-analysis was to outline the therapeutic effects of PF extracts on various models of immunoglobulin a (IgA) nephropathy; (2) Methods: Medline, Embase, and Cochrane databases were used to find relevant studies. All prospective interventional studies that evaluated the effect of PF extract versus placebo on rat models of chronic renal disorders were assessed according to the international guidelines; (3) Results: Our search yielded 23 unique records, out of which only five were included in the analysis. Our results showed that administration of PF extracts led to a statistically significant reduction in proteinuria and PCNA levels in rats that received high doses of the extract as well as in the PCNA level and DNA synthesis in rats that received low doses of the extract. The evaluated outcomes benefited from a low degree of heterogeneity; (4) Conclusions: Some of the evaluated outcomes were significantly reduced by both high and low doses of extracts from Perilla frutescens. Further studies are needed to determine the exact effect over IgA nephropathy in human subjects.

Sublytic C5b-9 Induces CCL3/4 Production and Macrophage Accumulation in Thy-1N Rats via PKC-α/p65/IRF-8 Axis.

Mesangioproliferative glomerulonephritis (MsPGN) is a common human kidney disease. Rat Thy-1 nephritis (Thy-1N) is an animal model widely used for the study of MsPGN. Thy-1N is not only sublytic C5b-9-dependent, but also related to pro-inflammatory cytokine production and macrophage (Mφ) accumulation in rat renal tissues. In this study, we found that the expression or phosphorylation of chemokine CCL3/4, CD68 (Mφ marker), IRF-8, PKC-α and NF-κB-p65 (p65) were all up-regulated both in the renal tissues of Thy-1N rats (in vivo) and in the glomerular mesangial cells (GMCs) upon sublytic C5b-9 stimulation (in vitro). Further experiments in vitro revealed that the phosphorylated PKC-α (p-PKC-α) could promote p65 phosphorylation, and then p-p65 enhanced IRF-8 expression through binding to IRF-8 promotor (-591 ~ -582 nt and -299 ~ -290 nt). Additionally, up-regulation or silencing of IRF-8 gene promoted or reduced CCL3/4 production, and then regulated Mφ chemotaxis. The underlying mechanism involved in IRF-8 binding to CCL3 promoter (-249 ~ -236 nt), which resulted in CCL3 gene transcription. The experiments in vivo showed that knockdown of renal PKC-α, p65, IRF-8 and CCL3/4 genes could inhibit CCL3/4 production, Mφ accumulation, GMC proliferation and proteinuria of Thy-1N rats. Furthermore, p-PKC-α, p-p65, IRF-8, CCL3/4 expression and Mφ accumulation were also increased in the renal tissues of MsPGN patients. Collectively, these findings indicate that sublytic C5b-9 induces CCL3/4 production and Mφ accumulation via PKC-α/p65/IRF-8 axis, and finally aggravates the pathological changes of MsPGN.

Current treatment of IgA nephropathy.

IgA nephropathy (IgAN) is the most common type of glomerulonephritis in Asia and the Western world. In most patients, it follows an asymptomatic to oligosymptomatic course and GFR loss, if any, is slow. The mainstay of therapy therefore is optimized supportive care, i.e., measures that lower blood pressure, reduce proteinuria, minimize lifestyle risk factors, and otherwise help to reduce non-specific insults to the kidneys. The value of immunosuppression has become controversial and if at all, systemic high-dose corticosteroid therapy should be considered for a few months taking into account patient characteristics that would caution against or preclude such therapy. In addition, adverse events related to corticosteroid therapy markedly increase as GFR declines. Beyond corticosteroids, there is little evidence that any additional immunosuppression is helpful, with the exception of mycophenolate mofetil in patients of Asian descent. A considerable number of clinical trials ranging from enteric coated budesonide to blockade of B-cell function to complement inhibitors are currently ongoing and will hopefully allow a more targeted therapy of high-risk patients with progressive IgAN in the future.

Assessment of the Link of ABCB1 and NR3C1 gene polymorphisms with the prednisolone resistance in pediatric nephrotic syndrome patients of Bangladesh: A genotype and haplotype approach.

Introduction: Nephrotic syndrome is a common pediatric kidney disease. Investigations on several genetic polymorphisms revealed an inconsistent influence on the resistance of patients to steroids. Objectives: This study aimed to identify the association of ABCB1 (1236C > T, 2677G > T, 3435C > T), NR3C1 (rs10482634, rs6877893), and CYP3A5 (CYP3A5*3) gene polymorphism as well as sociodemographic and clinicopathological parameters with the risk of developing prednisolone resistance in pediatric patients with nephrotic syndrome. Methods: A case-control analysis was performed on 180 nephrotic syndrome patients. Among them, 30 patients were classified as prednisolone resistant group, and 150 were classified as prednisolone sensitive group. Genotyping was performed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Results: No significant association of 1236C > T polymorphism with the risk of prednisolone resistance (p > 0.05) was found. The GT heterozygous of 2677G > T was found to be significantly associated with the development of prednisolone resistance (OR = 3.9, p = 0.034). In the case of 3435C > T, a statistically significant association was observed in TC heterozygous and TT mutant homozygous genotypes (OR = 0.38, p = 0.047; OR = 3.06, p = 0.038, respectively) with prednisolone resistance. For rs10482634 polymorphism, the AG heterozygous and AG+GG genotypes were significantly linked with prednisolone resistance (OR = 2.40, p = 0.033; OR = 2.36, p = 0.034, respectively). We found no association with the risk of prednisolone resistance with rs6877893 and CYP3A5*3 polymorphism (p > 0.05). CTC and TGT haplotypes of ABCB1 and GA haplotype of NR3C1 were also associated with the increased risk of pediatric prednisolone resistance (OR = 4.47, p = 0.0003; OR = 2.71, p = 0.03; and OR = 4.22, p = 0.022, consecutively). We also observed the correlation of different sociodemographic and clinicopathological factors with prednisolone resistance in pediatric nephrotic syndrome. Conclusion: Our findings showed a significant association of ABCB1 and NR3C1 gene polymorphisms with prednisolone resistant pediatric nephrotic syndrome.

Matrix-assisted laser desorption/ionization mass spectrometry imaging to uncover protein alterations associated with the progression of IgA nephropathy.

IgA nephropathy (IgAN) is one of the most diffuse glomerulonephrites worldwide, and many issues still remain regarding our understanding of its pathogenesis. The disease is diagnosed by renal biopsy examination, but potential pitfalls still persist with regard to discriminating its primary origin and, as a result, determining patient outcome remains challenging. In this pilot study, matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) was performed on renal biopsies obtained from patients with IgAN (n = 11) and other mesangioproliferative glomerulonephrites (MesPGN, n = 6) in order to enlighten proteomic alterations that may be associated with the progression of IgAN. Differences in the proteomic profiles of IgAN and MesPGN tissue could clearly be detected using this approach and, furthermore, 14 signals (AUC ≥ 0.8) were observed to have an altered intensity among the different CKD stages within the IgAN group. In particular, large increases in the intensity of these signals could be observed at CKD stages II and above. These signals primarily corresponded to proteins involved in either inflammatory and healing pathways and their increased intensity was localized within regions of tissue with large amounts of inflammatory cells or sclerosis. Despite much work in recent years, our molecular understanding of IgAN progression remains incomplete. This pilot study represents a promising starting point in the search for novel protein markers that can assist clinicians in better understanding the pathogenesis of IgAN and highlighting those patients who may progress to end-stage renal disease.

Clinicopathological Analysis of Glomerular Disease of Adult Onset Nephrotic Syndrome in an Indian Cohort- A Retrospective Study.

INTRODUCTION: Primary glomerular disease presenting with adult onset nephrotic syndrome are a major cause of chronic renal failure worldwide. The spectrum of renal disease presenting with nephrotic syndrome has undergone a gradual change globally over the course of time. However, there still exist regional differences in the incidence of primary glomerular diseases causing adult onset nephrotic syndrome. AIM: To observe the spectrum of renal diseases presenting with adult onset nephrotic syndrome with comparative analysis of changing trends over the last five decades with regards to Western and Indian literature. MATERIALS AND METHODS: Subjects included patients with age of 18-80 years presenting with nephrotic syndrome. Renal biopsies with immunofluoroscence studies were performed in all patients. Baseline clinical parameters of serum urea, creatinine, albumin, globulin, cholesterol, 24 hour urine protein and urine microscopy were recorded. Descriptive statistics was used and results were expressed as frequencies, percentages, and mean±standard deviation. RESULTS: A total of 227 patients (72% males) were included for the study. Primary glomerular diseases formed 74.01% of total cases and majority of patients included males in the 4th decade. Minimal Change Disease (MCD) (15.8%) including its variants was the most common primary glomerular disease for adult onset of nephrotic syndrome followed by Mesangial proliferative Glomerulonephritis (MSGN) (13.2%). Membranous nephropathy and Type I Membranoproliferative Glomerulonephritis (MPGN) individually accounted for 12.3% of patients. Focal and Segmental Glomerulosclerosis (FSGS) accounted for only 11% of patients. Although, increased incidence of FSGS has been observed worldwide, there exist important regional differences in primary glomerular diseases in Indian population. MCD remains a major glomerular disease for adult onset nephrotic syndrome in different parts of India. CONCLUSION: Our study over three years represents important data of regional variations of primary glomerular diseases presenting with adult onset nephrotic syndrome.

Pathological patterns of mesangioproliferative glomerulonephritis seen at a tertiary care center.

Background: Mesangioproliferative glomerulonephritis (MesPGN) is a common morphological pattern that encompasses several groups of renal diseases including IgA nephropathy (IgAN), IgM nephropathy (IgMN), lupus nephritis (LN), C1q nephropathy (C1qN) and other entities. Objectives: The aim of this study was to analyze the pathological findings and the clinical features of cases of MesPGN seen at the king Abdulaziz University, in Saudi Arabia. Patients and Methods: A total of 750 percutaneous native renal biopsies were seen at our institution from January 2000 to December 2011. All the cases diagnosed as MesPGN on light microscopy (LM) were retrieved from the archives of pathology. The pathological features and the clinical data of these cases were reviewed. The clinical data was available for 80 cases only. Results: A total of 103 cases (14%) met the inclusion criteria for the diagnosis of MesPGN. The most common diagnostic entity was IgMN (46.6%) followed by IgAN (30%) along with few cases of class II LN, C1qN, minimal change disease (MCD), Alport's syndrome, focal segmental glomerulosclerosis (FSGS), thin basement membrane disease (TBMD), and fibrillary glomerulonephritis. The most common clinical presentation was nephrotic syndrome seen in 71% of 80 cases, followed by hematuria (14%). Histologically, focal mesangial proliferation was seen in 62% while diffuse proliferation was seen in 38% of the cases. Conclusion: Mesangioproliferative glomerulonephritis is an important cause of nephrotic syndrome in young adults in the western region of Saudi Arabia. Future studies from the region are needed to elucidate the clinical relevance of mesangial cell proliferation to the end stage kidney diseases.

Mesangioproliferative glomerulonephritis: a 30-year prognosis study.

BACKGROUND: Diffuse mesangioproliferative glomerulonephritis (MesP) is the most commonly diagnosed type of glomerulonephritis (GN) in Denmark, with an incidence of 10.8 million per year. In the present study, the 30-year renal survival was estimated. METHODS: A retrospective cohort investigation of 140 patients with biopsy-proven MesP was performed between the period 1967-2006. Factors influencing renal survival were investigated using Cox regression analysis. RESULTS: Renal survival at 5, 10, 20 and 30 years was 87, 78, 59 and 50%, respectively. Female survival after 30 years was significantly better than male survival (70 vs. 40%, p = 0.049). Multivariate analysis, adjusted for age, estimated glomerular filtration rate (GFR) and nephrotic syndrome (NS) was performed for each sex individually. An increase in GFR was associated with a hazard risk (HR) of 0.98 (p = 0.02) in women and 0.99 (p = 0.006) in men. Older age was associated with a HR of 1.04 (p = 0.02) in women and 1.03 (p = 0.004) in men. NS had a poorer prognosis in men (HR 2.53, p = 0.01), but not in women (HR 0.54, p = 0.38). CONCLUSION: Increasing age and decreasing GFR were adversely associated with renal death. Renal prognosis was better for women after 30 years, and NS resulted in a poorer prognosis in men. This suggests that disease course and prognosis are different between men and women.

Mesangioproliferative glomerulonephritis in an infant with Prader-Willi syndrome.

Prader-Willi syndrome (PWS) is a neurobehavioral disorder characterized mainly by neonatal hypotonia, dysmorphic features, hypogonadism, mental retardation and behavioral problems. The PWS has not been associated with renal complications. We report the case of an infant with Prader-Willi syndrome due to loss of the paternal copy of chromosome 15q11.2-13, who presented with severe proteinuria and microscopic hematuria. Renal biopsy revealed mesangioproliferative glomerulonephritis (MPGN). The early onset of the primary MPGN in this infant make us consider a possible association between the deficiency of the paternally expressed genes from the 15q11-q13 region and the renal disease.