Interleukin-6 production induced in peripheral blood mononuclear cells by a serum factor from IgA nephropathy patients is inhibited in vitro by specific sugars

The basal production of IL-6 by cultured peripheral blood mononuclearcells (PBMC) from patients with IgAN, is markedly higher (A,109 pg/ml) as compared to that of PBMC of either patients withoutclinical signs (I, 39 pg/ml) or appropriate controls (C, 44pg/ml). When PBMC from healthy subjects were incubated in thepresence of sera from patients A, the IL-6 production was stronglyenhanced. No such an effect was observed by stimulating PBMCwith sera from the other two groups of subjects (I, C). In anotherexperiment we observed that the IL-6 production stimulated byserum from patients A could be inhibited by addition of specificmonosaccharides. The inhibitory effect was rapidly abolishedwhen the sugar-containing medium was substituted with the originalone. Finally molecular components from serum of A were grosslyseparated by gel column chromatography. Individual fractionswere incubated with PBMC of C: fractions with Mr > 30 000highly stimulated the release of IL-6 (up to 1320 pg/ml); fractionswith lower molecular weight were inactive. The data suggest the presence of an IL-6 releasing factor inthe serum of IgAN patients. Although the chemical nature ofsuch a factor is not yet established, the observations reportedfocus our attention to the lectins family. Since this factorseems potentially important in the understanding of the pathogenesisof IgAN, both its isolation and structural/functional characterizationdeserve further efforts.     

Natural history of immunoglobulin A nephropathy and predictive factors of prognosis: a long-term follow up of 204 cases in China

Aim: Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. However, its natural history and risk factors are not well understood. Our aim was to identify the clinical and pathological factors that could predict disease prognosis in Chinese patients. Methods: We studied 204 biopsy‐diagnosed IgAN patients, who were followed for an average of 6.1 years (range, 4–15 years). Chronic kidney disease (CKD) classified according to the Kidney Disease Outcomes Quality Initiative practice guidelines. Renal pathological lesions were graded single‐blindedly according to the Haas classification. The glomerular filtration rate was estimated by the Modification of Diet in Renal Disease equation for Chinese subjects. Results: Patients with CKD were classified as stage 1 (38.10%), stage 2 (35.40%), stage 3 (13.30%), stage 4 (9.90%) and stage 5 (3.30%). During the follow up, 31 patients had progressed to end‐stage renal disease. The renal survival rate following biopsy was 85.1% at the fifth year, and 77.1% at the 10th year. Univariate analysis indicated that patients who were male, had hypertension, proteinuria of more than 1 g/day, renal impairment (estimated glomerular filtration rate, <60 mL/min.1.73 m²), and a high histological grading were associated with poor prognosis. Multivariate analysis indicated that the relative risk of renal failure for patients was 3.9 (P = 0.000) for patients with renal impairment, 2.8 (P = 0.019) for patients with hypertension, and 2.0 (P = 0.003) for patients with high histological grading. Conclusion: We described the natural history of IgAN through follow ups of a relatively large cohort of patients. Most patients were biopsied at an early stage; however, the long‐term prognosis was still poor. Patients with renal impairment, hypertension and advanced histological involvement had the highest risk for disease progression.     

Interleukin-12 alters the physicochemical characteristics of serum and glomerular IgA and modifies glycosylation in a ddY mouse strain having high IgA levels.

BACKGROUND: We recently developed a ddY mouse strain having high IgA levels (HIGA) that provided a murine model of IgA nephropathy. We additionally showed that administration of interleukin (IL)-12, a potent helper T (Th)1-inducing cytokine, induced an apparent reduction in serum IgA levels. In the present study, we assessed the influence of IL-12 administration on several physicochemical characteristics of nephritogenic IgA molecules in HIGA mice. METHODS: HIGA mice received daily intraperitoneal injections of IL-12 or control injections of phosphate-buffered saline for 3 weeks. Crescent formation and levels of circulating and glomerular IgA were analysed. Moreover, potential changes in charge, size, and glycosylation of serum and glomerular IgA were investigated. RESULTS: In the IL-12 group, glomerular IgA deposition was faint, although crescent formation was more marked than in the control group. Serum IgA levels in IL-12 mice were significantly lower than in controls. IL-12-treated mice also showed markedly decreased acidic and polymeric IgA both in sera and in glomerular eluate. A lectin-binding study revealed a markedly reduced ratio of sialylated and galactosylated IgA in the sera and in glomerular eluate from HIGA mice kidneys. IL-12 treatment significantly increased sialylation and galactosylation of circulating IgA, although glycosylation of IgA in glomerular eluate remained low. CONCLUSIONS: In HIGA mice showing under-glycosylation, IL-12 administration may lead to changes in the physicochemical characteristics of IgA, and this may occur through a shift to Th1. These results suggest that the Th1 and Th2 balance might play a role in the development of immunopathologic lesions in this model of IgA nephropathy.     

T-cell subsets,interleukin-2 receptor expression and production of interleukin-2 in minimal change nephrotic syndrome

This study was designed to investigate T-lymphocyte subsets interleukin-2 receptor (IL-2R) expression and IL-2 production in minimal change nephrotic syndrome (MCNS). Peripheral blood T-lymphocytes and IL-2R expression were analysed using fluorescein isothiocyanatelabelled CD3, CD4, CD8 and CD25 monoclonal antibodies with flow cytometry. IL-2 production was determined by enzyme immunoassay. Ten children with MCNS in relapse and in remission were evaluated. Thirteen healthy children served as controls. The patients in relapse demonstrated a moderate decrease in the total absolute lymphocyte counts and CD8(+) T-lymphocytes compared with controls (P<0.05) and had a greatly increased IL-2R expression in frashly isolated, unstimulated peripheral lymphocytes compared with patients in remission and controls. While this was not statistically significant, IL-2R expression on cultured lymphocytes stimulated with phytohaemagglutinin was significantly elevated in relapse compared with those in remission and controls (P<0.05). IL-2 production did not correlate well with IL-2R expression and there was no significant difference between the groups. Our results suggest that T-cell subset changes and high IL-2R expression on peripheral lymphocytes may indicate the presence of stimulated T-cell populations in MCNS which could contribute to the immunopathogenesis.     

Association of nitric oxide production and apoptosis in a model of experimental nephropathy.

BACKGROUND: In recent studies increased amounts of nitric oxide (NO) and apoptosis have been implicated in various pathological conditions in the kidney. We have studied the role of NO and its association with apoptosis in an experimental model of nephrotic syndrome induced by a single injection of adriamycin (ADR). METHODS: The alteration in the NO pathway was assessed by measuring nitrite levels in serum/urine and by evaluating the changes in vascular reactivity of the isolated perfused rat kidney (IPRK) system. Rats were stratified into control groups and ADR-induced nephropathy groups. These two groups were then divided into: group 1, animals receiving saline; and group 2, animals receiving aminoguanidine (AG) which is a specific inhibitor of inducible-NO synthase. On day 21, rats were sacrificed after obtaining material for biochemical analysis. RESULTS: Histopathological examination of the kidneys of rats treated with ADR revealed focal areas of mesangial proliferation and mild tubulointerstitial inflammation. They also had significantly higher levels of proteinuria compared with control and treatment groups (P < 0.05). Urine nitrite levels were significantly increased in the ADR-nephropathy group (P < 0.05). In the IPRK phenylephrine and acetylcholine related responses were significantly impaired in the ADR-nephropathy group. Apoptosis was not detected in controls. However, in the ADR-nephropathy group, numerous apoptotic cells were identified in the tubulointerstitial areas. Double staining revealed numerous interstitial apoptotic cells to stain for ED1, a marker for monocytes/macrophages. Treatment with AG prevented the impairment of renal vascular bed responses and reduced both urine nitrite levels and apoptosis to control levels. CONCLUSION: We suggest that interactions between NO and apoptosis are important in the pathogenesis of the ADR-induced nephrosis.     

Re-biopsy in a patient with IgA nephropathy showing success of treatment with cyclosporin A and angiotensin-II receptor blocker

We report a patient with IgA nephropathy (IgAN) showing reduction of proteinuria and histological improvement of renal injury with cyclosporin A (CsA) and angiotensin-II receptor blocker (ARB) therapy. The amount of urinary protein was reduced from 4.4 to 1.8 g/24 h after 2 months of CsA (150 mg/day) therapy, and further, to 0.4 g/24 h after 1 month of the combination therapy with ARB (candesartan, 4 mg/day). A renal re-biopsy, after treatment with CsA for 3 months and ARB for 1 month, demonstrated a reduction of IgA deposits, disappearance of crescents, re-separation of foot process fusion and decrease of interstitial cellular infiltration. After CsA therapy for 20 months and ARB for 18 months, the patient currently remains stable without deterioration of serum creatinine (1.7 mg/dl) and urinary protein excretion (0.5 g/day). These findings seem to indicate that combination therapy with CsA and ARB is effective for achieving histological improvement and protecting against deteriorated renal function, in addition to reducing proteinuria, in IgAN. Received: October 1, 2001 / Accepted: April 10, 2002     

Heat shock response inhibits NF-kappaB activation and cytokine production in murine Kupffer cells

BACKGROUND: Kupffer cells play a crucial role in the pathogenesis of sepsis through production of proinflammatory mediators and control of systemic endotoxemia. The anti-inflammatory effects of heat shock response (HSP) have been well documented. However, the role of HSP in lipopolysaccharide (LPS) induced Kupffer cell activation has not been fully investigated. In this study, we investigated the effects of HSP on LPS induced Kupffer cell NF-kappaB activation and cytokine production. MATERIALS AND METHODS: Kupffer cells were isolated from mice by collagenase digestion and HSP was induced by culturing Kupffer cells with sodium arsenite. Kupffer cells were stimulated in vitro by LPS. Heat shock protein (HSP)-70 expression and cytoplasmic IkappaBalpha protein was determined by Western blot. Supernatant tumor necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-10 levels were measured by ELISA. NF-kappaB activation was analyzed by electrophoresis mobility shift assay. Cytokine and IkappaBalpha mRNA expression were determined by RT-PCR. Toll-like receptor 4 expression on Kupffer cells was determined by flow cytometry. RESULTS: HSP pre-conditioning significantly inhibited LPS-induced cytokine TNF-alpha and IL-6 production and mRNA expression. NF-kappaB activation and IkappaBalpha degradation induced by LPS were attenuated by HSP. HSP up-regulated expression of IkappaBalpha mRNA. No effect of HSP on cell surface expression of TLR4 was observed. CONCLUSIONS: Increased IkappaBalpha stability and up-regulation of IkappaBalpha gene expression may be one of the mechanisms of the inhibition of LPS induced Kupffer cell activation by HSP. HSP also inhibited expression of the anti-inflammatory cytokine IL-10, and the mechanism and biological significance of this effect merit further investigation.     

Angiotensin II further enhances type IV collagen production stimulated by platelet-derived growth factor and fibroblast growth factor-2 in cultured human mesangial cells

SUMMARY: Angiotensin II (Ang II) is considered to play a role in the development of glomerulosclerosis, which is characterized by excessive accumulation of mesangial matrix after mesangial cell proliferation. We have reported that platelet-derived growth factor (PDGF) and fibroblast growth factor-2 (FGF-2) stimulate type IV collagen production by cultured human mesangial cells (HMC). Although Ang II is well known to have a mitogenic effect in various kinds of cells, its role in the production of extracellular matrix is still undetermined. This study was designed to examine the effect of Ang II and its interaction with PDGF and FGF-2 in type IV collagen production by HMC. Cultured HMC were incubated with Ang II with or without PDGF or FGF-2 for 72 h and type IV collagen, fibronectin and laminin in the cell supernatants were measured. Ang II (10⁻⁶–10⁻⁸) itself did not change the production of type IV collagen, fibronectin, laminin and transforming growth factor-β. PDGF and FGF-2 enhanced type IV production, although they did not stimulate the production of fibronectin and laminin. Ang II further increased the stimulating effect of PDGF and FGF-2 in type IV collagen production in a dose-dependent manner. This effect of Ang II was completely blocked by Ang II type I receptor antagonist (Losartan). These data imply that Ang II is a potent stimulator of type IV collagen production by HMC in the presence of growth factors.     

Upregulation of microRNA-200a in bone marrow mesenchymal stem cells enhances the repair of spinal cord injury in rats by reducing oxidative stress and regulating Keap1/Nrf2 pathway

Spinal cord injury (SCI) is a common disease with high incidence, disability rate and treatment cost. microRNA (miR)-200a is reported to inhibit Keap1 to activate Nrf2 signaling. This study aimed to explore the effects of lentivirus-mediated miR-200a gene-modified bone marrow mesenchymal stem cells (BMSCs) transplantation on the repair of SCI in a rat model. BMSCs were isolated from the bone marrow of Sprague–Dawley rats. MiR-200a targeting to Keap1 was identified by luciferase reporter gene assay. The expressions of Keap1, nuclear factor erythroid 2-related factor 2 (Nrf2), NAD(P)H-dependent quinone oxidoreductase 1 (NQO-1), heme oxygenase-1 (HO-1) and glutamate-cysteine ligase catalytic subunit (GCLC) were detected by Western blotting in SCI rats. The locomotor capacity of the rats was evaluated using the Basso, Beattie, and Bresnahan scale. The levels of malondialdehyde (MDA), activities of superoxide dismutase (SOD), and catalase (CAT) were measured. miR-200a inhibited Keap-1 3′ UTR activity in BMSCs. Transplantation of BMSCs with overexpression of miR-200a or si-Keap1 increased locomotor function recovery of rats after SCI, while decreased MDA level, increased SOD, CAT activities, and Nrf2 expression together with its downstream HO-1, NQO1, GCLC protein expressions in SCI rat. These results indicated that overexpressed miR-200a in BMSCs promoted SCI repair, which may be through regulating antioxidative signaling pathway.