Twenty-five cases of minimal change nephrotic syndrome(minimal change disease, MCD) with mesangial IgA deposition were evaluated electron microscopically. The thickness of the glomerular basement membrane(GBM) was 3875 +/- 1271 A and 3056 +/- 1201 A in adults and children, respectively. Alteration of the GBM was noted in 3 adults and eight children: splitting in 4, focal thinning in one, widening of the lamina rara interna in 10, and widening of the lamina rara externa in 4 cases. Minimal mesangial electron dense deposits were found in all but one adult, and an increase of the mesangial matrix and minimal mesangial proliferation were observed in 8 and 6 cases, respectively. Electron microscopic findings show representative findings of MCD in our cases. A relationship between the GBM alterations in these cases and frequent association of hematuria is suggested and discussed.
Adolescent ; Adult ; Child ; Child, Preschool ; Female ; Glomerular Mesangium/*metabolism ; Human ; Immunoglobulin A/*metabolism

OBJECTIVES: To investigate the possible role of mononuclear cells and their products in the pathogenesis of IgA nephropathy, in vitro expression of ICAM-1 on cultured mouse mesangial cell (MC) was examined after stimulation with mononuclear cell culture supernatant from patients with IgA nephropathy. METHODS: Peripheral blood mononuclear cells (PBMC) were isolated and cultured from 18 patients with primary IgA nephropathy, 8 normal controls and 5 patients with non-IgA nephropathy (FSGS 1, MGN 3, MPGN 1). ICAM-1 expression on cultured mouse MC by TNF-alpha, IL-1 beta and culture supernants of PBMC were analyzed using a cell ELISA method. The concentration of IL-1 beta and TNF-alpha in culture supernatants was measured by using a commercially available radioimmunoassay kit. RESULTS: Addition of human recombinant TNF-alpha induced an increased ICAM-1 expression in a dose-dependent manner. The expression of ICAM-1 was further increased after co-stimulation with TNF-alpha and IL-1 beta. Addition of PBMC culture supernatants into mouse MC induced significantly higher expression of ICAM-1 by supernatants from the patients with IgA nephropathy compared with that from normal controls. The concentration of TNF-alpha and IL-1 beta in supernatants from the patients with IgA nephropathy was significantly higher than that from those with non-IgA nephropathy. CONCLUSION: TNF-alpha and IL-1 released from mononuclear cells induced the up-regulation of ICAM-1 expression and this may be related to the immune pathogenesis of IgA nephropathy.
Animal ; Cells, Cultured ; Glomerular Mesangium/immunology ; Glomerular Mesangium/cytology ; Glomerulonephritis, IGA/immunology* ; Glomerulonephritis, IGA/etiology ; Human ; Intercellular Adhesion Molecule-1/metabolism* ; Interleukin-1/secretion ; Interleukin-1/pharmacology ; Leukocytes, Mononuclear/immunology ; Mice ; Tumor Necrosis Factor/secretion ; Tumor Necrosis Factor/pharmacology

OBJECTIVETo determine the effect of hypercholsterolemia induced by a high-lipid diet on glomerulosclerosis.

METHODSTwenty nephrotic syndrome (NS) Wistar rats administrated adriamycin (ADR) with a single intravenous dose of 5 mg/kg body weight, were divided into the standard and high-lipid chow groups. Another 20 weight-matched non-NS rats that received a vehicle alone were grouped as control. Urinary protein excretion and serum cholesterol were assayed; image analysis and techniques of pathology, immunohistochemistry, and molecular biology were used to determine morphological changes in glomeruli and the production of glomerular mesangial matrices in different groups.

RESULTSThe serum total cholesterol level was significantly higher in rats with high-lipid chow in both non-NS [(2.2 +/- 0.3) g/L vs. (0.9 +/- 0.1) g/L, P < 0.01] and NS [(9.5 +/- 0.2) g/L vs. (2.3 +/- 0.3) g/L, P < 0.01]. The urinary protein excretion was significantly higher in the high-lipid diet rats than in standard chow rats [(76.2 +/- 24.2) mg/24h vs. (44.8 +/- 13.6) mg/24h, P < 0.05] in NS rats. Although increases in the mesangial matrix and mesangial cells were observed in rats with high-lipid diet in both NS and non-NS group, more obvious pathological changes were found in NS group, such as lipid deposits and foam cell formation in mesangial areas, and progressing to focal and segmental glomerulosclerosis in some glomeruli. The immunohistochemical asay showed that the production of 3 major components (collagen IV, fibronectin, and laminin) was increased in NS group, especially in the rats with high-lipid chow. The increased expression of laminin mRNA was also detected with slot blotting in both NS and non-NS rats with high-lipid chow, and it was more obvious in the rats with NS.

CONCLUSIONOur findings indicated that diet-induced hyperlipidemia can lead to over-production of mesangial matrix components, and further aggravate glomerulosclerosis in ADR-induced nephrosis.

Animals ; Dietary Fats ; pharmacology ; Doxorubicin ; Fibronectins ; metabolism ; Glomerular Mesangium ; metabolism ; pathology ; Hypercholesterolemia ; metabolism ; Laminin ; metabolism ; Male ; Nephrotic Syndrome ; chemically induced ; metabolism ; pathology ; Proteinuria ; urine ; Rats ; Rats, Wistar

BACKGROUND: Transforming growth factor-beta (TGF-beta) stimulates renal fibrosis in various renal diseases including IgA nephropathy. METHODS: We examined whether immunoglobulin A (IgA) stimulated TGF-beta1 synthesis in human mesangial cells (MCs), and whether this effect was mediated through the protein kinase C (PKC) pathway. We measured the intraglomerular TGF-beta1 mRNA expression by using competitive RT-PCR, and this was compared with various parameters in IgA nephropathy patients. RESULTS: The IgA aggregate increased the TGF-beta1 mRNA expression in MCs, while this expression was not affected by the culture media or IgG aggregate. Phorbol 12-myristate 13-acetate and calphostin C did not influence the TGF-beta1 mRNA expression that was increased by the IgA aggregate. Intraglomerular TGF-beta1 mRNA expression was significantly correlated with creatinine clearance (r=-0.764, p=0.027), daily proteinuria (r=0.781, p=0.022), serum creatinine (r=0.884, p=0.004), and tubulointerstitial changes (r=0.809, p=0.015). Glomerular TGF-beta1 mRNA expression was associated with an increased tendency for glomerulosclerosis (r=0.646, p=0.084). After 4 years, patients with a high expression of intraglomerular TGF-beta1 mRNA showed a tendency for an decrease of their renal function. CONCLUSION: The IgA aggregate increased TGF-beta1 mRNA expression in MCs, and this was independent of the PKC pathway. The evaluation of intraglomerular TGF-beta1 mRNA expression could be useful in predicting the progression of IgA nephropathy.
Cells, Cultured ; Female ; Glomerular Mesangium/*cytology/metabolism ; Glomerulonephritis, IGA/metabolism/pathology ; Humans ; Immunoglobulin A/*pharmacology ; Male ; Proteins/*metabolism ; RNA, Messenger/*metabolism ; Research Support, Non-U.S. Gov't

BACKGROUNDThe renoprotective mechanisms of adenosine monophosphate (AMP)-activated protein kinase (AMPK) agonist - metformin have not been stated clearly. We hypothesized that metformin may ameliorate inflammation via AMPK interaction with critical inflammatory cytokines. The aim of this study was to observe the effects of metformin on expression of nuclear factor-κB (NF-κB), monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1) and transforming growth factor-beta 1 (TGF-β1) induced by high glucose (HG) in cultured rat glomerular mesangial cells (MCs).

METHODSMCs were cultured in the medium with normal concentration glucose (group NG, 5.6 mmol/L), high concentration glucose (group HG, 25 mmol/L) and different concentrations of metformin (group M1, M2, M3). After 48-hour exposure, the supernatants and MCs were collected. The expression of NF-κB, MCP-1, ICAM-1, and TGF-β1 mRNA was analyzed by real time polymerase chain reaction. Western blotting was used to detect the expression of AMPK, phospho-Thr-172 AMPK (p-AMPK), NF-κB p65, MCP-1, ICAM-1, and TGF-β1 protein.

RESULTSAfter stimulated by HG, the expression of NF-κB, MCP-1, ICAM-1, TGF-β1 mRNA and protein of MCs in group HG increased significantly compared with group NG (P < 0.05). Both genes and protein expression of NF-κB, MCP-1, ICAM-1, TGF-β1 of MCs induced by high glucose were markedly reduced after metformin treatment in a dose-dependent manner (P < 0.05). The expression of p-AMPK increased with the rising of metformin concentration, presenting the opposite trend, while the level of total-AMPK protein was unchanged with exposure to HG or metformin. Conlusion Metformin can suppress the expression of NF-κB, MCP-1, ICAM-1 and TGF-β1 of glomerular MCs induced by high glucose via AMPK activation, which may partly contribute to its reno-protection.

AMP-Activated Protein Kinases ; metabolism ; Animals ; Cells, Cultured ; Glomerular Mesangium ; cytology ; Glucose ; pharmacology ; Mesangial Cells ; drug effects ; metabolism ; Metformin ; pharmacology ; NF-kappa B ; metabolism ; Rats

OBJECTIVETo investigate the effect of exendin-4 on the expression of monocyte chemoattractant protein-1 (MCP-1) and fibronectin (FN) in rat glomerular mesangial cells in vitro.

METHODSRat glomerular mesangial cells were divided into 5 groups, namely control group, tumor necrosis factor-α (TNF-α) group (10 ng/ml), TNF-α (10 ng/ml)+E1 (1 nmol/L exendin-4) group, TNF-α (10 ng/ml)+E5 (5 nmol/L exendin-4) group, and TNF-α (10 ng/ml)+E10 (10 nmol/L exendin-4) group. After cultured 24 h or 48 h, RNA were extracted to determine the expression of MCP-1 with real-time PCR, the supernatant were collected to determine the expression of MCP-1 and FN with ELISA.

RESULTSCompared with control group, the cells treated with TNF-α for 24 h showed significantly increase the expression of MCP-1 and FN (P<0.01), exendin-4 significantly reduced the expression of MCP-1 and FN in TNF-α+E5 group and TNF-α+E10 group (P<0.05). After 48h incubation, the expression of MCP-1 and FN increased significantly in TNF-α group (P<0.01), which was lowered by exendin-4 in TNF-α+E1,TNF-α+E5 and TNF-α+E10 groups (P<0.05).

CONCLUSIONExendin-4 has an intrinsic capability to concentration- and time-dependently inhibit TNF-α-induced expression of MCP-1 and FN in rat mesangial cells, suggesting the beneficial effect of exendin-4 in preventing and treating diabetic nephropathy.

Animals ; Cells, Cultured ; Chemokine CCL2 ; metabolism ; Diabetic Nephropathies ; metabolism ; Glomerular Mesangium ; cytology ; Mesangial Cells ; drug effects ; metabolism ; Peptides ; pharmacology ; Rats ; Tumor Necrosis Factor-alpha ; pharmacology ; Venoms ; pharmacology

Extracellular Signal-Regulated MAP Kinases ; metabolism ; Glomerular Mesangium ; immunology ; Glycosylation ; Humans ; Immunoglobulin A ; metabolism ; Phosphorylation ; Receptors, Fc ; analysis ; genetics ; Receptors, Transferrin ; analysis ; genetics

Interleukin (IL)-6 is an autocrine growth factor for mesangial cells. It is not known whether high glucose influences IL-6 production in mesangial cells. Angiotensin II (AGII) is involved in the progression of renal diseases including diabetic nephropathy. Therefore, we evaluated the effects of high glucose in concert with AGII on IL-6 production in human mesangial cells and the modulation by blocking AGII. After 48 hr of culture, IL-6 mRNA expression was analyzed by reverse transcription and polymerase chain reaction (PCR). Quantitative determination of IL-6 concentrations in the culture supernatants of mesangial cells was performed using a sandwich enzyme immunoassay kit. Incubation of mesangial cells with high glucose (450 mg/dL) reduced the ratio of PCR products for IL-6 to beta-actin on densitometric results, while AGII (10(-7)M) increased it. The IL-6 secretion in the supernatant was also increased by AGII and decreased by high glucose. The IL-6 mRNA expression and IL-6 secretion in combination of high glucose and AGII were higher than those in high glucose and similar with those in control media. The addition of losartan (10(-6)M) or captopril (10(-6)M) to high glucose had no additional effects on IL-6 production. These results suggest that whereas AGII increases IL-6 production, high glucose decreases it. The IL-6 production of mesangial cells in diabetic milieu may be complicated and depend on the local effects of high glucose and/or AGII.
Angiotensin II/*pharmacology ; Captopril/pharmacology ; Cells, Cultured ; Gene Expression/drug effects ; Glomerular Mesangium/cytology/*metabolism ; Glucose/*pharmacology ; Humans ; Interleukin-6/*biosynthesis/genetics/secretion ; Losartan/pharmacology

OBJECTIVETo study the clinicopathologic features of membranous nephropathy coexisting with IgA nephropathy.

METHODSThe renal biopsies performed in Peking University First Hospital during the period from January, 1998 to April, 2006 were retrospectively reviewed. The clinicopathologic features of 11 cases of membranous nephropathy coexisting with IgA nephropathy were studied. Electron microscopy with immunogold labeling for IgG and IgA were also performed.

RESULTSThe mean age of patients was 39.9 years. The male-to-female ratio was 1:2.9. The patients mainly presented with proteinuria. Proteinuria of nephrotic level was seen in 7 cases (63.6%). Seven cases also had associated microscopic hematuria. None of them showed evidence of renal insufficiency. Cases with secondary diseases, such as hepatitis virus infection and systemic lupus erythematosus, were excluded from the study. Histologically, vacuolation and thickening of glomerular basement membrane was seen. There was also mild mesangial hypercellularity and increase in mesangial matrix. Occasional glomeruli with crescent formation were identified in 2 cases. Immunofluorescence study showed granular staining for IgG and C3 along glomerular capillary walls, in addition to clumps of IgA deposits in mesangium. Electron microscopy revealed subepithelial and mesangial electron-dense deposits. Immunogold labeling showed IgG and IgA localized in the subepithelial and mesangial deposits respectively.

CONCLUSIONMembranous nephropathy coexisting with IgA nephropathy possesses the clinicopathologic features of both components. It might be caused by independent occurrence of the two entities.

Adult ; Female ; Glomerular Basement Membrane ; immunology ; pathology ; ultrastructure ; Glomerular Mesangium ; immunology ; pathology ; ultrastructure ; Glomerulonephritis, IGA ; complications ; immunology ; pathology ; Glomerulonephritis, Membranous ; complications ; immunology ; pathology ; Humans ; Immunoglobulin A ; metabolism ; Immunoglobulin G ; metabolism ; Kidney Glomerulus ; immunology ; pathology ; ultrastructure ; Male ; Middle Aged ; Retrospective Studies

Diabetic nephropathy is characterized by an expansion of the glomerular mesangium, caused by mesangial cell proliferation and an excessive accumulation of extracellar matrix (ECM) proteins, which eventually leading to glomerulosclerosis. TGF-beta1 was found to play an important role in the accumulation of ECM in the kidney. In this study, TGF-beta1 RNA interference was used as an effective therapeutic strategy. The inhibitory effect of TGF-beta1 small interfering RNAs (siRNAs) on the high glucose-induced overexpression of TGF-beta1 in rat mesangial ceys (RMCs). A high levels of glucose induces TGF-beta1 mRNA and protein, and TGF-beta1 siRNAs reduce the ability of high glucose to stimulate their expression. We also examined the inhibitory effect of TGF-beta1 siRNAs on the expression of plasminogen activator inhibitor (PAI)-1 and Collagen Type I which are down-regulators of TGF-beta1. The expression of TGF-beta1, PAI-1 and Collagen Type I was increased in RMCs that were stimulated by 30 mM glucose. TGF-beta1 siRNAs reduces high glucose-induced TGF-beta1, PAI-1, and Collagen Type I mRNA and protein expression in a dose-dependent manner. In conclusion, the present study demonstrates that TGF-beta1 siRNAs effectively inhibits TGF-beta1 mRNA and protein expression in RMCs. These suggest that TGF-beta1 siRNAs through RNAi may be a useful tool for developing new therapeutic applications for the treatment of diabetic nephropathy.
Transforming Growth Factor beta1/*metabolism ; Rats, Sprague-Dawley ; Rats ; RNA, Small Interfering/*metabolism ; Microscopy, Fluorescence ; Mesangial Cells/*metabolism ; Male ; Glucose/*metabolism ; Glomerular Mesangium/*metabolism ; Gene Expression Regulation ; Diabetic Nephropathies/pathology ; Collagen Type I/metabolism ; Cells, Cultured ; Cell Proliferation ; Animals