SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Glomerulonephritis

170

Alport syndrome is a hereditary glomerulopathy with proteinuria and nephritis caused by defects in genes encoding type IV collagen in the glomerular basement membrane. All male and most female patients develop end-stage renal disease. Effective treatment to stop or decelerate the progression of proteinuria and nephritis is still under investigation. Here we showed that combination treatment of mild electrical stress (MES) and heat stress (HS) ameliorated progressive proteinuria and renal injury in mouse model of Alport syndrome. The expressions of kidney injury marker neutrophil gelatinase-associated lipocalin and pro-inflammatory cytokines interleukin-6, tumor necrosis factor-α and interleukin-1β were suppressed by MES+HS treatment. The anti-proteinuric effect of MES+HS treatment is mediated by podocytic activation of phosphatidylinositol 3-OH kinase (PI3K)-Akt and heat shock protein 72 (Hsp72)-dependent pathways in vitro and in vivo. The anti-inflammatory effect of MES+HS was mediated by glomerular activation of c-jun NH(2)-terminal kinase ½ (JNK1/2) and p38-dependent pathways ex vivo. Collectively, our studies show that combination treatment of MES and HS confers anti-proteinuric and anti-inflammatory effects on Alport mice likely through the activation of multiple signaling pathways including PI3K-Akt, Hsp72, JNK1/2, and p38 pathways, providing a novel candidate therapeutic strategy to decelerate the progression of patho-phenotypes in Alport syndrome.

Concepts: Kidney, Nephrology, Collagen, Glomerulus, In vivo, In vitro, Glomerulonephritis, Alport syndrome

168

BACKGROUND: Pathologic studies played an important role in evaluating patients with Alport syndrome besides genotyping. Difficulties still exist in diagnosing Alport syndrome (AS), and misdiagnosis is a not-so-rare event, even in adult patient evaluated with renal biopsy. METHODS: We used nested case–control study to investigate 52 patients previously misdiagnosed and 52 patients initially diagnosed in the China Alport Syndrome Treatments and Outcomes Registry e-system. RESULTS: We found mesangial proliferative glomerulonephritis (MsPGN, 26.9%) and focal and segmental glomerulosclerosis (FSGS, 19.2%) were the most common misdiagnosis. FSGS was the most frequent misdiagnosis in female X-linked AS (fXLAS) patients (34.8%), and MsPGN in male X-linked AS (mXLAS) patients (41.2%). Previous misdiagnosed mXLAS patients (13/17, 76.5%) and autosomal recessive AS (ARAS) patients (8/12, 66.7%) were corrected after a second renal biopsy. While misdiagnosed fXLAS patients (18/23, 78.3%) were corrected after a family member diagnosed (34.8%) or after rechecking electronic microscopy and/or collagen-IV alpha-chains immunofluresence study (COL-IF) (43.5%) during follow-up. With COL-IF as an additional criterion for AS diagnosis, we found that patients with less than 3 criteria reached have increased risk of misdiagnosis (3.29-fold for all misdiagnosed AS patients and 3.90-fold for fXLAS patients). CONCLUSION: We emphasize timely and careful study of electronic microscopy and COL-IF in pathologic evaluation of AS patients. With renal and/or skin COL-IF as additional criterion, 3 diagnosis criteria reached are the cutoff for diagnosing AS pathologically.

Concepts: Medical terms, Diagnosis, Pathology, Medical diagnosis, Glomerulonephritis, Sex linkage, Dominance, Alport syndrome

167

Kawasaki disease (KD) is a systemic vasculitis and affects many organ systems. It often presents sterile pyuria, microscopic hematuria, and proteinuria due to renal involvement. The aims of this study were to define clinical characteristics of acute KD patients with pyuria and to analyze meaning of pyuria in KD.

Concepts: Nephrology, Vasculitis, Nephrotic syndrome, Arthralgia, Glomerulonephritis, Kawasaki disease, Urinalysis, IgA nephropathy

139

Immunoglobulin A vasculitis (IgAV), also referred to as Henoch-Schönlein purpura, is the most common form of childhood vasculitis. The pathogenesis of IgAV is still largely unknown. The disease is characterized by IgA1-immune deposits, complement factors and neutrophil infiltration, which is accompanied with vascular inflammation. Incidence of IgAV is twice as high during fall and winter, suggesting an environmental trigger associated to climate. Symptoms can resolve without intervention, but some patients develop glomerulonephritis with features similar to IgA nephropathy that include hematuria, proteinuria and IgA deposition in the glomerulus. Ultimately, this can lead to end-stage renal disease. In IgA nephropathy immune complexes containing galactose-deficient (Gd-)IgA1 are found and thought to play a role in pathogenesis. Although Gd-IgA1 complexes are also present in patients with IgAV with nephritis, their role in IgAV is disputed. Alternatively, it is has been proposed that in IgAV IgA1 antibodies are generated against endothelial cells. We anticipate that such IgA complexes can activate neutrophils via the IgA Fc receptor FcαRI (CD89), thereby inducing neutrophil migration and activation, which ultimately causes tissue damage in IgAV. In this Review, we discuss the putative role of IgA, IgA receptors, neutrophils and other factors such as infections, genetics and the complement system in the pathogenesis of IgA vasculitis.

Concepts: Immune system, Inflammation, Kidney, Immunoglobulin A, Glomerulonephritis, Phagocyte, Kidney diseases, IgA nephropathy

101

Systemic lupus erythematosus (SLE) is an autoimmune disease, which results in various organ pathologies. However, current treatment towards SLE is suboptimal. Erythropoietin (EPO) has been shown to promote SLE recovery, but clinical application can be limited by its haematopoiesis-stimulating effects. EPO-derived helix-B peptide (ARA290) is non-erythrogenic but has been reported to retain the anti-inflammatory and tissue-protective functions of EPO. Therefore, here we investigated the effects and potential mechanisms of ARA290 on SLE. The administration of ARA290 to pristane-induced SLE and MRL/lpr mice significantly suppressed the level of serum antinuclear autoantibodies (ANAs) and anti-dsDNA autoantibodies, reduced the deposition of IgG and C3, and ameliorated the nephritis symptoms. Moreover, the serum concentrations of inflammatory cytokine IL-6, MCP-1 and TNF-α in SLE mice were reduced by ARA290. Further, ARA290 decreased the number of apoptotic cells in kidney. In vitro experiment revealed that ARA290 inhibited the inflammatory activation of macrophages and promoted the phagocytotic function of macrophages to apoptotic cells. Finally, ARA290 did not induce haematopoiesis during treatment. In conclusion, ARA290 ameliorated SLE, which at least could be partly due to its anti-inflammatory and apoptotic cell clearance promoting effects, without stimulating haematopoiesis, suggesting that ARA290 could be a hopeful candidate for SLE treatment.

Concepts: Immune system, Rheumatoid arthritis, Systemic lupus erythematosus, Lupus erythematosus, Glomerulonephritis

44

Occupational exposure to respirable crystalline silica (cSiO2, quartz) is etiologically linked to systemic lupus erythematosus (lupus) and other human autoimmune diseases (ADs). In the female NZBWF1 mouse, a widely used animal model that is genetically prone to lupus, short-term repeated intranasal exposure to cSiO2 triggers premature initiation of autoimmune responses in the lungs and kidneys. In contrast to cSiO2’s triggering action, consumption of the ω-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) prevents spontaneous onset of autoimmunity in this mouse strain. The aim of this study was to test the hypothesis that consumption of DHA will prevent cSiO2-triggered autoimmunity in the female NZBWF1 mouse. Mice (6 wk old) were fed isocaloric AIN-93G diets containing 0.0, 0.4, 1.2 or 2.4% DHA. Two wk after initiating feeding, mice were intranasally instilled with 1 mg cSiO2 once per wk for 4 wk and maintained on experimental diets for an additional 12 wk. Mice were then sacrificed and the lung, blood and kidney assessed for markers of inflammation and autoimmunity. DHA was incorporated into lung, red blood cells and kidney from diet in a concentration-dependent fashion. Dietary DHA dose-dependently suppressed cSiO2-triggered perivascular leukocyte infiltration and ectopic lymphoid tissue neogenesis in the lung. DHA consumption concurrently inhibited cSiO2-driven elevation of proinflammatory cytokines, B-cell proliferation factors, IgG and anti-dsDNA Ig in both bronchoalveolar lavage fluid and plasma. DHA’s prophylactic effects were further mirrored in reduced proteinuria and glomerulonephritis in cSiO2-treated mice. Taken together, these results reveal that DHA consumption suppresses cSiO2 triggering of autoimmunity in female NZBWF1 mice as manifested in the lung, blood and kidney. Our findings provide novel insight into how dietary modulation of the lipidome might be used to prevent or delay triggering of AD by cSiO2. Such knowledge opens the possibility of developing practical, low-cost preventative strategies to reduce the risk of initiating AD and subsequent flaring in cSiO2-exposed individuals. Additional research in this model is required to establish the mechanisms by which DHA suppresses cSiO2-induced autoimmunity and to ascertain unique lipidome signatures predictive of susceptibility to cSiO2-triggered AD.

Concepts: Immune system, Cell nucleus, Rheumatoid arthritis, Nephrotic syndrome, Systemic lupus erythematosus, Lupus erythematosus, Glomerulonephritis, Proteinuria

37

Lupus nephritis is a common and severe manifestation of systemic lupus erythematosus, and an important cause of both acute kidney injury and end-stage renal disease. Despite its aggressive course, lupus nephritis is amenable to treatment in the majority of patients. The paradigm of immunosuppressive treatment for lupus nephritis has evolved over the past few decades from corticosteroids alone to corticosteroids combined with cyclophosphamide. Sequential treatment regimens using various agents have been formulated for induction and long-term maintenance therapy, and mycophenolate mofetil has emerged as a standard of care option for both induction and maintenance immunosuppressive treatment. The current era has witnessed the emergence of multiple novel therapeutic options, such as calcineurin inhibitors and biologic agents that target key pathogenetic mechanisms of lupus nephritis. Clinical outcomes have improved in parallel with these therapeutic advances. This Review discusses the evidence in support of current standard of care immunosuppressive treatments and emerging therapies, and describes their roles and relative merits in the management of patients with lupus nephritis.

Concepts: Nephrology, Corticosteroid, Systemic lupus erythematosus, Glomerulonephritis, Immunosuppressive drug, Lupus nephritis, Cyclophosphamide, Mycophenolic acid

32

B cells contribute to multiple aspects of autoimmune disorders and may play a role in triggering disease. Thus, targeting B cells may be a promising strategy for treating autoimmune disorders. Better understanding of the B cell subsets that are responsible for the development of autoimmunity will be critical for developing efficient therapies. Here we have reported that B cells expressing the transcription factor T-bet promote the rapid appearance of autoantibodies and germinal centers in spontaneous murine models of systemic lupus erythematosus (SLE). Conditional deletion of T-bet from B cells impaired the formation of germinal centers and mitigated the development of kidney damage and rapid mortality in SLE mice. B cell-specific deletion of T-bet was also associated with lower activation of both B cells and T cells. Taken together, our results suggest that targeting T-bet-expressing B cells may be a potential target for therapy for autoimmune diseases.

Concepts: Cell nucleus, Rheumatoid arthritis, Systemic lupus erythematosus, Lupus erythematosus, Glomerulonephritis, Autoimmune diseases, Sjögren's syndrome, Myasthenia gravis

28

Background: A multicenter case-control study on IgA nephropathy (IgAN) was conducted to develop an evidence-based clinicopathologic classification of IgAN for predicting long-term renal outcome. Methods: Two hundred and eighty-seven patients including those with isolated hematuria or very mild proteinuria were enrolled. During a median follow-up of 9.3 years after biopsy, 49 patients (17%) progressed to end stage renal disease (ESRD). The associations between pathological variables and the need for chronic dialysis was examined by multivariate logistic regression analysis separately in patients who required dialysis earlier than 5 years (Early Progressors) and those who required dialysis within 5 to 10 years (Late Progressors) after biopsy. Results: Independent pathological variables predicting progression to ESRD were global sclerosis, segmental sclerosis and fibrous crescents for Early Progressors, and global sclerosis and cellular/fibrocellular crescents for Late Progressors. Four histological grades, HG 1, HG 2, HG 3 and HG 4, were established corresponding to <25%, 25-49%, 50-74% and =75% of glomeruli exhibiting cellular or fibrocellular crescents, global sclerosis, segmental sclerosis or fibrous crescents. Eleven (7%) patients in HG 1, 12 (16%) in HG 2, 13 (31%) in HG 3 and 13 (68%) in HG 4 progressed to ESRD. Multivariate logistic analysis revealed that the risk of progression to ESRD was significantly higher in HG 2, 3 and 4 than in HG 1 (odds ratio, 2.4, 5.7 and 27.6 vs. 1.0). Conclusions: Our evidence-based histologic classification can identify the magnitude of the risk of progression to ESRD and is useful for predicting long-term renal outcome in IgAN.

Concepts: Regression analysis, Logistic regression, Renal failure, Chronic kidney disease, Nephrology, Cancer, Glomerulonephritis, IgA nephropathy

28

INTRODUCTION: Among various lupus renal vascular changes, thrombotic microangiopathy (TMA) presented with most severe clinical manifestations and high mortality. The pathogenesis of TMA in systemic lupus erythematosus (SLE) was complicated. The aim of this study was to assess clinical manifestations, laboratory characteristics, pathological features and risk factors for clinical outcomes of lupus nephritis patients co-existing with renal TMA in a large cohort in China. METHODS: Clinical and renal histopathological data of 148 patients with biopsy-proven lupus nephritis were retrospectively analyzed. Serum complement factor H, ADAMTS-13 activity, antiphospholipid antibodies and C4d deposition on renal vessels were further detected and analyzed. RESULTS: In the 148 patients with lupus nephritis, 36 patients were diagnosed as co-existing with renal TMA based on pathological diagnosis. Among the 36 TMA patients, their clinical diagnoses of renal TMA were as followings: 2 patients combining with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome, 2 patients combining with anti-phospholipid syndrome, 2 patients with malignant hypertension, 1 patient with scleroderma and the other 29 patients presenting with isolated renal TMA. Compared with non-renal TMA group, patients with renal TMA had significantly higher urine protein (7.09+/-4.64 vs. 4.75+/-3.13 g/24h, P=0.007) and serum creatinine (159, 86-215 vs. 81, 68-112 mumol/l, P<0.001), higher scores of total activity indices (AI) (P<0.001), endocapillary hypercellularity (P<0.001), subendothelial hyaline deposits (P=0.003), interstitial inflammation (P=0.005), glomerular leukocyte infiltration (P=0.006), total chronicity indices (CI) (P=0.033), tubular atrophy (P=0.004) and interstitial fibrosis (P=0.018). Patients with renal TMA presented with poorer renal outcome (P=0.005) compared with non-TMA group. Renal TMA (hazard ratio (HR): 2.772, 95% confidence interval: 1.009-7.617, P=0.048) was an independent risk factor for renal outcome in patients with lupus nephritis. The renal outcome was poorer for those with both C4d deposition and decreased serum complement factor H in TMA group (P=0.007). CONCLUSIONS: There were various causes of renal TMA in lupus nephritis. Complement over-activation via both classical and alternative pathways might play an important role in the pathogenesis of renal TMA in lupus nephritis.

Concepts: Immune system, Rheumatology, Systemic lupus erythematosus, Glomerulonephritis, Complement system, Thrombocytopenia, Lupus nephritis, Antiphospholipid syndrome