Mesangial Sclerosis Research Articles

Role of transforming growth factor‐β/Smad signalling pathway in enhanced production of glomerular extracellular matrix in IgA nephropathy of high‐serum‐IgA ddY mice

SUMMARY: The high‐IgA inbred strain (HIGA) of ddY mice, an animal model of human IgA nephropathy, shows consistently high serum IgA levels, progressive mesangial sclerosis and IgA deposition, and elevated renal expression of transforming growth factor (TGF)‐β. In the present study the role of the TGF‐β/Smad signalling pathway in extracellular matrix (ECM) production was assessed in cultured mesangial cells derived from HIGA mice. the production of type I and type IV collagens in response to TGF‐β1, expression of Smad2, Smad4, Smad7, and Sp1 and p300, and phosphorylation of Smad2 by TGF‐β1 were assessed in cultured mesangial cells derived from HIGA mice at the age of 10 weeks by comparison with age‐matched C57BL/6 mice as controls. In addtion, the expression of p300 and type I and type IV collagens in renal tissues of HIGA mice at the age of 60 weeks was determined. the production of type I and type IV collagens by cultured mesangial cells in HIGA mice was markedly upregulated compared with that in C57BL/6 mice. Although protein expression levels of Smad2, Smad4, Smad7, and Sp1 in the mesangial cells were simiiar in the two mouse strains, upregulation of p300 was marked in HIGA mice. Expression of p300 in renal tissues of HIGA mice was also enhanced in HIGA mice when compared with C57BL/6 mice. In HIGA mice, p300 expression was upregulated in the mesangial cells both in vitro and in vivo. It appears that the upregulation of p300 may be related to glomerular sclerosis associated with IgA nephropathy in HIGA mice.

WT1 is a key regulator of podocyte function: reduced expression levels cause crescentic glomerulonephritis and mesangial sclerosis.

Glomerular disease is one of the most common causes of end-stage renal failure. Increasing evidence suggests that these glomerulopathies are frequently caused by primary lesions in the renal podocytes. One of the major consequences of podocyte lesions is the accumulation of mesangial matrix in the glomerular basement membrane, a process called glomerulosclerosis. Mesangial sclerosis is one of the most consistent findings in Denys-Drash patients and can be caused by dominant mutations in the Wilms' tumor 1 gene (WT1). The underlying mechanism, however, is poorly understood. WT1 is expressed in the podocytes throughout life, but its function in this cell type is unknown. Combining Wt1-knockout and inducible yeast artificial chromosome transgenic mouse models, we demonstrate that reduced expression levels of WT1 result in either crescentic glomerulonephritis or mesangial sclerosis depending on the gene dosage. Strikingly, the two podocyte-specific genes nphs1 and podocalyxin are dramatically downregulated in mice with decreased levels of Wt1, suggesting that these two genes act downstream of Wt1. Taken together, our data provide genetic evidence that reduced levels of Wt1 are responsible for the pathogenesis of two distinct renal diseases and offer a molecular explanation for the increased occurrence of glomerulosclerosis in patients with WAGR syndrome.

Complications of IgA nephropathy in a non-insulin-dependent diabetes model, the Akita mouse.

The Akita mouse, which has a mutation (Cys96Tyr) in the insulin 2 gene (Ins2(Akita)), is a model for diabetes. The male Akita mouse has diabetes, while females develop mild diabetes. This study aimed to investigate renal complications in the Akita mouse model, which has been maintained in a heterozygous state Ins2(Akita) (+/-) with a C57BL/6 background (B6). Renal function (BUN, creatinine), serum IgA concentrations and histological changes in the kidneys were evaluated in diabetic and control mice in a B6 background. Five each of male and female mice per group (diabetes vs. control) were killed at 10, 20, 30 and 40 weeks of age. The influence of major histocompatibility antigens (MHC) on renal complications was tested using male diabetic mice in a C3H/He (C3H) background. When compared with controls, diabetic males, but not females, developed impaired renal function with elevation of serum IgA after 30 weeks of age. Diabetic glomerulosclerosis advanced with age in both sexes. Diffuse granular mesangial deposits of IgA were detected by immunofluorescence microscopy in diabetic males after 20 weeks. We tested whether the IgA-associated lesions were influenced by MHC using diabetic males in a C3H background. Similar degrees of diabetic glomerulosclerosis and glomerular IgA deposition were found in mice with C3H and B6 backgrounds. Akita mouse is a unique mouse model showing both mesangial sclerosis and IgA nephropathy.

Prognostic significance of persistent massive proteinuria in IgA nephropathy: 10‐year follow‐up study of 366 cases

Prognostic significance of persistent massive proteinuria in IgA nephropathy: 10‐year follow‐up study of 366 cases

Genetic polymorphism in angiotensinogen promotor region affects progression of IgA nephropathy

The purpose of the present study was to evaluate the role of angiotensinogen (AGT) gene polymorphisms in the progression of IgA nephropathy (IgAN). The association of the haplotypes defined by A-20C and M235T, which correspond to G-6 A polymorphisms, with the severity of glomerular or interstitial lesions and renal prognosis were investigated. Patients with histologically proven IgAN were recruited after informed consent was obtained for the genetic study, which was approved by the ethics committee of our institute. Genomic DNA from each patient was prepared from peripheral blood leucocytes using an automatic DNA isolation system (NA-100, Kurabo, Osaka, Japan). A–C transition at nucleotide −20, G–A transition at −6, C–T transition at +68 and M235T variant at exon two in the AGT gene were determined as described previously.1,2 The renal survival rate was analysed for 114 IgAN patients with a creatinine clearance (Ccr) level of 70 mL/min or greater and followed up more than 24 months. The patients with haplotype T235 and C-20 (n = 63) were compared with those without T235 and C-20 (n = 51) for age, sex, blood pressure, proteinuria, serum Cr, Ccr at the time of renal biopsy, drugs administered, and severity of renal histopathologic lesion. Light microscopic evaluation of all specimens was performed in a double blind fashion according to the grading classification described previously, including glomerular cellular proliferation, mesangial matrix increase, global or segmental sclerosis, endocapillary proliferation, leucocyte exudation, duplication of glomerular basement membrane, crescent formation, and tufts adhesion to Bowman’s capsule as well as tubulointerstitial lesions.3 The Kaplan-Meier method and the Cox proportional hazards regression model analysed the time course from renal biopsy to end point (initiation of dialysis or sCr level doubled after the time of diagnosis). Several covariates were selected by a stepwise backward method and the effects of these covariates were expressed by a hazard ratio. P < 0.05 was considered statistically significant. The genotype distributions in the present study were not different from that in Hardy–Weinberg equilibrium. The genotype and allele frequencies of AGT variants were compatible with previous studies for Japanese population.1,4 Haplotype analysis showed a complete linkage disequilibrium between M235T and A-20C alleles (linkage-disequilibrium coefficient: D′, 1.00). Because the AGT gene variant at −20 was observed only in a subset of the 235T alleles, the following haplotypes were determined: T235 and C-20; T235 and A-20; and M235 and A-20. The incidence of hypertension was not different between each haplotype of AGT. An association study of histopathological findings revealed that patients with haplotype T235 and C-20 had significantly higher grading scores in crescent formation (P = 0.017) than those without haplotype T235 and C-20. Renal survival rate was significantly lower in the patients with haplotype T235 and C-20 (Fig. 1, P = 0.003). The Cox proportional hazards regression model showed an increased hazard ratio (HR) for haplotype T235 and C–20 of 5.9 from multivariate analysis (Fig. 2; 95% CI, 2.1–16.7; P < 0.001). Furthermore, in IgAN patients without administration of angiotensin I converting enzyme inhibitors (n = 77), renal survival rate was significantly lower in those with haplotype T235 and C–20 (P = 0.011). Figure 1. Effect of AGT haplotype on the renal survival rate in IgAN patients. Solid and dashed lines represent the renal survival rate in the patients with and without haplotype T235 and C–20, respectively. Download figure to PowerPoint Figure 2. Cox proportional hazards regression model to test the predictors for renal survival time in multivariate analysis. Covariates were selected by stepwise backward analysis. U-protein, urinary protein; HT at renal biopsy, hypertensives at the time of renal biopsy; ACEI, angiotensin I converting enzyme inhibitor. The bars represent the 95% confidence intervals of hazard ratio. Download figure to PowerPoint This work provides the evidence that the C–20 gene polymorphism of AGT, a subset of 235T alleles, is associated with histopathological severity of glomerular injury, and progression of renal dysfunction in Japanese patient with IgAN.

Glomerulosclerosis is transmitted by bone marrow–derived mesangial cell progenitors

We found that ROP Os/+ (Os/+) mice had diffuse glomerulosclerosis and glomerular hypertrophy and that their mesangial cells (the vascular smooth muscle cells of the glomerulus) displayed an apparent sclerosing phenotype. Since mesangial cells are the major source of scar tissue in glomerulosclerosis, we postulated that the sclerosis phenotype was carried by mesangial cell progenitors and that this phenotype could be derived from the bone marrow (BM). Therefore, we transplanted BM from Os/+ mice into congenic ROP +/+ mice (+/+ mice), which have normal glomeruli. We found that glomeruli of +/+ recipients of Os/+ marrow contained the Os/+ genotype, were hypertrophied, and contained increased extracellular matrix. Clones of recipient glomerular mesangial cells with the donor genotype were found in all +/+ recipients that developed mesangial sclerosis and glomerular hypertrophy, whereas +/+ recipients of +/+ BM had normal glomeruli. Thus, the sclerotic (Os/+) or normal (+/+) genotype and phenotype were present in, and transmitted by, BM-derived progenitors. These data show that glomerular mesangial cell progenitors are derived from the BM and can deliver a disease phenotype to normal glomeruli. Glomerular lesions may therefore be perpetuated or aggravated, rather than resolved, by newly arriving progenitor cells exhibiting a disease phenotype.

Glomerulosclerosis is transmitted by bone marrow-derived mesangial cell progenitors.

We found that ROP Os/+ (Os/+) mice had diffuse glomerulosclerosis and glomerular hypertrophy and that their mesangial cells (the vascular smooth muscle cells of the glomerulus) displayed an apparent sclerosing phenotype. Since mesangial cells are the major source of scar tissue in glomerulosclerosis, we postulated that the sclerosis phenotype was carried by mesangial cell progenitors and that this phenotype could be derived from the bone marrow (BM). Therefore, we transplanted BM from Os/+ mice into congenic ROP +/+ mice (+/+ mice), which have normal glomeruli. We found that glomeruli of +/+ recipients of Os/+ marrow contained the Os/+ genotype, were hypertrophied, and contained increased extracellular matrix. Clones of recipient glomerular mesangial cells with the donor genotype were found in all +/+ recipients that developed mesangial sclerosis and glomerular hypertrophy, whereas +/+ recipients of +/+ BM had normal glomeruli. Thus, the sclerotic (Os/+) or normal (+/+) genotype and phenotype were present in, and transmitted by, BM-derived progenitors. These data show that glomerular mesangial cell progenitors are derived from the BM and can deliver a disease phenotype to normal glomeruli. Glomerular lesions may therefore be perpetuated or aggravated, rather than resolved, by newly arriving progenitor cells exhibiting a disease phenotype.

Heminephrectomy causes the progression of glomerulosclerosis and apoptosis in high IgA strain of ddY (HIGA) mice

Background: The nephron reduction in IgA nephropathy is critical for the newly established prognosis of this disease. A high immunoglobulin A inbred strain of ddY mouse (HIGA mouse) showed progressive mesangial sclerosis with elevated renal expression of transforming growth factor (TGF)‐β,1 however, the progression of the renal lesion of this mouse is relatively mild with rare association of active crescentic glomerulonephritis. However, although nephron reduction causes progressive renal injury, the modifications of glomerular lesions by nephron reduction are dependent upon the pathological background of each strain. Thus, we investigated the influence of nephron reduction by heminephrectomy on the renal lesions of the HIGA mouse.Methods: Five‐week‐old HIGA mice were heminephrectomized (Nx), and were evaluated in comparison with a sham‐operated group (S) at 40 weeks old. Measurements of renal function, blood pressure and serum levels of immunoglobulins (IgG, IgA, and IgM) were performed. Histological findings, including glomerular enlargement, matrix expansion, immunoglobulin depositions (IgG, IgA, and IgM), expressions of cytokines (TGF‐β, TNF‐α, and IL‐6) and extracellular matrix proteins were analysed. PCNA and TUNEL stainings were performed. In addition, mRNA expressions of renin‐angiotensin systems (RAS; angiotensinogen and angiotensin converting enzyme (ACE)) were also investigated.Results: The physiological and serological data showed no significant difference between Nx and S. In Nx, the glomerular tuft area and ratio of mesangial matrix area for one tuft were significantly increased and glomerular IgG and IgM deposits were significantly expanded in the paramesangium. However, IgA was not significantly increased. The glomerular expressions of cytokines (TGF‐β, TNF‐α, and IL‐6) and extracellular matrix proteins (fibronectin, collagen type I and IV) were significantly increased in this group. In contrast to the significant decrease of PCNA‐positive cells, TUNEL‐positive cells were significantly increased in Nx. The total mRNA expression of ACE was also significantly increased in the renal cortex of Nx.Conclusion: Heminephrectomy of HIGA mice may be a potential model for the research into the progressive glomerulosclerosis of human IgA nephropathy. The pathological role of apoptosis is apparently involved in these disease processes, possibly through up‐regulated RAS.

Clinical and histological improvement with long-term, low-dose cyclosporin A in a patient with severe IgA nephropathy

We report the case of an 11-year-old girl with nephrotic syndrome with massive proteinuria and microscopic hematuria. Her first renal biopsy specimen (June 1997) showed diffuse/segmental mesangial proliferative glomerulonephritis with capillary wall thickening, crescent, and sclerosis by light microscopy, as well as diffuse/global moderate deposition of IgA, C3, and fibrinogen predominantly in the mesangium, and partly along the capillary wall, by immunofluorescent microscopy. After the patient failed to show remission with the usual dose of prednisolone and azathioprine, cyclosporin A was administered, in addition to dipyridamole, warfarin, and prednisolone (on alternative days). In consequence, the proteinuria had completely disappeared after 6 weeks of this regimen and microscopic hematuria had disappeared after 8 months of the regimen. A second renal biopsy was performed in August 1998. The epithelial proliferation and crescent seen in the first biopsy specimen had disappeared, and only mesangial proliferation and sclerosis persisted, without histological evidence of cyclosporin-induced nephrotoxicity. A third renal biopsy was performed in March, 2000. IgA deposition in glomeruli had disappeared in this biopsy specimen. Low-dose cyclosporin A therapy resulted in dramatic improvements in both clinical manifestations and renal histological findings, without detrimental effects on renal function.

In vitro evidence for differential involvement of CTGF, TGFbeta, and PDGF-BB in mesangial response to injury.

Connective tissue growth factor (CTGF) is a profibrotic growth factor, which is upregulated in wound healing and renal fibrosis, including anti-Thy-1.1 nephritis. The kinetics of CTGF mRNA expression in anti-Thy-1.1 nephritis suggested that CTGF regulation might contribute to glomerular response to injury downstream of transforming growth factor-beta (TGFbeta). In anti-Thy-1.1 nephritis the initial damage is followed by mesangial repair and limited sclerosis, which involves mesangial cell (MC) activation (alpha-smooth-muscle actin (alphaSMA) expression), proliferation, migration, and extracellular matrix production. The present in vitro study addresses the possible role of CTGF in these different aspects of mesangial response to injury, and how CTGF activity might relate to effects of TGFbeta and platelet-derived growth factor-BB (PDGF-BB). Immunostaining and ELISA showed that alphaSMA expression and transformation of MC into myofibroblast-like cells was induced by TGFbeta, but not affected by PDGF-BB, CTGF, or neutralizing anti-CTGF antibodies. [(3)H]thymidine incorporation and Ki67 staining demonstrated that, unlike PDGF-BB, neither CTGF nor TGFbeta induced the proliferation of MC. In contrast, both CTGF and TGFbeta induced MC migration, as evidenced by approximation of wound edges in scrape-wounded, non-proliferating rat MC monolayers. In addition, fibronectin expression was upregulated by both CTGF and TGFbeta, as measured by dot-blot analysis. Anti-CTGF completely blocked the effect of added CTGF. Moreover, anti-CTGF significantly reduced TGFbeta-induced increase in fibronectin. It thus appears that CTGF is specifically involved in a subset of the adaptive changes of MC involved in mesangial repair and sclerosis, which makes it an interesting candidate target for future intervention strategies.

Isolated diffuse mesangial sclerosis and Wilms tumor suppressor gene

Diffuse mesangial sclerosis is a rare renal disease, occurring either in isolation or as part of Denys-Drash syndrome. Denys-Drash syndrome originates from mutations of the Wilms tumor suppressor gene (WT1 ). We describe the presence of WT1 mutations in 7 Japanese children with isolated diffuse mesangial sclerosis. (J Pediatr 2001;138:425-7)

Analysis of Glomerulosclerosis and Atherosclerosis in Lecithin Cholesterol Acyltransferase-deficient Mice

To evaluate the biochemical and molecular mechanisms leading to glomerulosclerosis and the variable development of atherosclerosis in patients with familial lecithin cholesterol acyl transferase (LCAT) deficiency, we generated LCAT knockout (KO) mice and cross-bred them with apolipoprotein (apo) E KO, low density lipoprotein receptor (LDLr) KO, and cholesteryl ester transfer protein transgenic mice. LCAT-KO mice had normochromic normocytic anemia with increased reticulocyte and target cell counts as well as decreased red blood cell osmotic fragility. A subset of LCAT-KO mice accumulated lipoprotein X and developed proteinuria and glomerulosclerosis characterized by mesangial cell proliferation, sclerosis, lipid accumulation, and deposition of electron dense material throughout the glomeruli. LCAT deficiency reduced the plasma high density lipoprotein (HDL) cholesterol (-70 to -94%) and non-HDL cholesterol (-48 to -85%) levels in control, apoE-KO, LDLr-KO, and cholesteryl ester transfer protein-Tg mice. Transcriptome and Western blot analysis demonstrated up-regulation of hepatic LDLr and apoE expression in LCAT-KO mice. Despite decreased HDL, aortic atherosclerosis was significantly reduced (-35% to -99%) in all mouse models with LCAT deficiency. Our studies indicate (i) that the plasma levels of apoB containing lipoproteins rather than HDL may determine the atherogenic risk of patients with hypoalphalipoproteinemia due to LCAT deficiency and (ii) a potential etiological role for lipoproteins X in the development of glomerulosclerosis in LCAT deficiency. The availability of LCAT-KO mice characterized by lipid, hematologic, and renal abnormalities similar to familial LCAT deficiency patients will permit future evaluation of LCAT gene transfer as a possible treatment for glomerulosclerosis in LCAT-deficient states.

Congenital nephrotic syndrome.

Congenital nephrotic syndrome (CNS) is a rare disorder that presents within 3 months of birth. It is characterized by massive proteinuria, edema,hypoalbuminemia, hyperlipidemia,hypogammaglobulinemia, and hypercoaguability. Without meticulous medical care and eventual renal transplantation, affected infants generally die by 6 months of age.CNS can have primary and secondary etiologies. The most common is CNS of the Finnish type. As a primary etiology, its cause remains unknown. Less common primary etiologies include diffuse mesangial sclerosis, minimal change nephrotic syndrome, and focal segmental glomerulosclerosis. Secondary CNS consists of known etiologies for which specific therapy is aimed at the underlying disease. These include infections, such as syphilis,toxoplasmosis, cytomegalovirus, hepatitis, and human immunodeficiency virus. Other secondary causes are mercury intoxication, genetic malformation syndromes such as XY gonadal dysgenesis, and systemic illnesses such as systemic lupus erythematosus and amyloidosis.Congenital nephrotic syndrome in Finland (CNF) constitutes the majority of CNS cases in the world. Infants who have idiopathic CNS in other parts of the world follow a similar course as infants who have CNF. Those who have CNF are born preterm, are small for gestational age, and have large placentas that comprise more than 25% of the birthweight. Affected infants develop proteinuria prenatally, and most exhibit edema within the first week of life. Distinctive physical features include wide cranial sutures, large open fontanelles, small nose, wide-set eyes,low-set ears, and umbilical hernia. In general, they feed and grow poorly because of substantial loss of proteins, effects of edema, and increased incidence of pyloric stenosis and reflux. They require early diagnosis and aggressive medical and surgical intervention.Diagnosis can be initiated prenatally. Elevated maternal serum and amniotic fluid alpha-fetoprotein (AFP)levels during the 15th to 20th weeks of gestation may identify those at risk,particularly in families that have a prior history. Because an elevated AFP level is nonspecific and can indicate many other obstetric complications,ultrasonography is helpful. Genetic analysis provides a definitive diagnosis. CNF has been linked to a defect in chromosome 19q13.1 and more specifically, to the“nephrin” gene. The product of this gene is a protein associated with the function of the glomerular filtration barrier. Mutations cause CNF and may be implicated in other diseases that involve proteinuria. Genetic analysis also differentiates patients who are carriers from those who ultimately develop CNF.Treatment for infants who have CNF focuses on reaching an ideal weight and nutritional status for renal transplantation, the only cure for the condition. Medical management includes providing a high-calorie and high-protein diet, vitamin supplementation,albumin administration, and diuretic therapy. Attention is directed at preventing and treating infections and thromboembolic events for which these infants are at high risk. Patients eventually need bilateral nephrectomy combined with peritoneal dialysis for ultimate renal transplantation. CNF does not recur following renal transplantation, and catch-up growth and normalization of development can be achieved.Infants in whom CNS is not treated have a complex and bleak clinical course. In vitro genetic analysis offers new hope for recognition and early intervention. Further, improvements in medical care and solid organ transplantation extend the hope for cure and normalization of growth and development. For some patients, CNS is no longer a fatal disease.Inheritance of this rare disorder usually is autosomal recessive,but sporadic cases have been found. Localization of the nephrin gene and association of CNF with mutations have allowed for improved prenatal diagnosis and medical intervention.

Immunohistochemical analysis of molecular events in tubulo-interstitial fibrosis in a mouse model of diffuse mesangial sclerosis (ICGN strain).

Diffuse mesangial sclerosis (DMS) is one of the hereditary glomerular diseases and histologically characterized by severe glomerulosclerosis and subsequent tubulo-interstitial fibrosis (TIF). In DMS patients, renal dysfunction correlates well with TIF, rather than with glomerular lesions. Thus, molecular mechanisms whereby TIF in DMS progresses should be addressed. Previously, we found that nephrotic ICGN mice manifest DMS-like lesions and develop renal dysfunction in accordance with onset of TIF. In the present study, we investigated fibrogenic events involved in the progression of TIF after DMS manifestation, using the DMS mouse model. Immunohistochemistry revealed that expression of transforming growth factor-beta (TGF-beta) was rare in the interstitial cells of the nephrotic mice at the early-stage of DMS, while the TGF-beta expression became evident in the late-stage DMS mice. Platelet-derived growth factor (PDGF) was mildly expressed in the distal tubules of the early-stage DMS mice, whereas the PDGF expression markedly increased at the late-stage of DMS. As a result, alpha-actin-positive myofibroblastic cells were found dominant in the interstitial spaces of the late-stage DMS mice. Finally, TIF became severe in accordance with the overexpressions of these molecules. Our results suggest that in our murine model: 1) persistent proteinuria leads to over-expression of TGF-beta and PDGF in non-glomerular areas; 2) these cytokines provoke interstitial myofibroblast accumulation; and 3) the myofibroblasts produce fibrotic matrix proteins in the interstitial spaces. This process may possibly contribute to the development of TIF in DMS patients.

Expression of decorin, biglycan, and collagen type I in human renal fibrosing disease

The extracellular matrix proteoglycans decorin and biglycan may have a pathogenic role in renal fibrosing disease via regulation of the activity of growth factors, such as transforming growth factor-beta, and effects on collagen type I fibrillogenesis. The expression of decorin and biglycan in human glomerular diseases characterized by mesangial sclerosis is unknown. Decorin, biglycan, and collagen type I were localized immunohistochemically in human renal biopsy cases of amyloidosis (N = 18), diabetic nephropathy (N = 11), fibrillary glomerulonephritis (N = 5), immunotactoid glomerulopathy (N = 5), light-chain deposition disease (N = 4), idiopathic mesangial sclerosis (N = 4), and nephrosclerosis (N = 6), and in morphologically normal tissues obtained from tumor nephrectomies (N = 8). Decorin and biglycan mRNA synthesis was evaluated by in situ hybridization. Decorin and biglycan protein were not identified in normal glomeruli. Decorin accumulated in amyloid deposits, but not in deposits of fibrillary glomerulonephritis or immunotactoid glomerulopathy. Biglycan weakly accumulated in amyloid deposits, and both decorin and biglycan weakly stained mesangial nodules in cases of morphologically advanced light-chain deposition disease and diabetic nephropathy. In all analyzed cases, irrespective of the underlying disease, decorin and biglycan accumulated in glomeruli in areas of fibrous organization of the urinary space and in areas of tubulointerstitial fibrosis. Biglycan, but not decorin, accumulated in the neointima of arteriosclerotic blood vessels. Decorin and biglycan mRNA synthesis was detected at sites of proteoglycan accumulation in glomeruli, interstitium, and neointima. Collagen type I colocalized with decorin and biglycan deposits. Differences in extracellular matrix proteoglycan composition may be diagnostically useful in distinguishing morphologically similar diseases. Distinct patterns of proteoglycan expression may be related to modulation of specific growth factor activity in different glomerular diseases.

A stepwise approach to the treatment of early onset nephrotic syndrome

We have retrospectively reviewed our single-center experience of the treatment of early onset nephrotic syndrome (NS). From 1991 to 1998, ten children with NS were treated. Kidney biopsy showed focal sclerosis (n=1), diffuse mesangial sclerosis (n=7), and congenital NS of the Finnish type (n=2). Associated conditions included incomplete Drash syndrome (n=1), Galloway-Mowat syndrome (n=1), and severe mental and motor retardation of unknown origin (n=3). From 1991 to 1997, five children with NS were treated. Bilateral nephrectomy (NX) was performed in three, one patient with severe retardation died at 4 years and NX was not performed in one patient who showed satisfactory growth and development. Three of these children were dialyzed and two were successfully transplanted. One patient was transplanted without previous dialysis. From 1997 to 1998, five children were treated with a regimen that included captopril and indomethacin (CAPTO/INDO). CAPTO/ INDO was successful in increasing serum protein in all patients and producing growth and development in four patients. In two patients CAPTO/INDO was successful only after unilateral NX. Our experience indicates that CAPTO/INDO may be a valuable treatment in patients with early onset NS. An individualized stepwise approach including unilateral NX should be considered to achieve optimal results.

Interleukin 12 induces crescentic glomerular lesions in a high IgA strain of ddY mice, independently of changes in IgA deposition.

Our recently established high immunoglobulin (Ig)A inbred strain (HIGA) of ddY mice showed constantly high serum IgA levels, progressive mesangial sclerosis accompanied by IgA deposits, and elevated renal expression of transforming growth factor (TGF)-beta, mimicking IgA nephropathy. In the present study, we assessed the role of the immune system, especially of T cells, in this strain. The in vitro production of interferon (IFN)-gamma, interleukin (IL)-4 and TGF-beta1 by splenic CD4+ T cells was assessed in HIGA mice at 14 and 28 weeks of age by comparison with age-matched C57BL/6 and BALB/c mice, T-helper (Th) 1, and Th2 prone controls respectively. Moreover, recombinant murine IL-12 was administered intraperitoneally to HIGA mice and serum IgA and renal lesions were analysed. The production of IFN-gamma by splenic CD4+ T cells was markedly upregulated in HIGA mice at both ages as compared with age-matched C57BL/6 and BALB/c mice. Although splenic CD4+ T cells from HIGA mice produced less IL-4 than those from BALB/c mice at both ages, the former produced significantly more IL-4 with age, which contrasted with the age-associated decrease in the latter. Moreover, TGF-beta1 production of these cells in HIGA mice was equal to or greater than that in the two groups of control mice at both ages. Daily intraperitoneal administration of IL-12 for 1 week significantly enhanced crescent formation with glomerular macrophage accumulation and interstitial cell infiltration, whereas it reduced the serum IgA level. In HIGA mice, Th1 is markedly upregulated from a young age and there is an age-associated Th2 increase with TGF-beta1 upregulation in helper T cells. The former may be related to the exacerbation of inflammatory renal lesions on IL-12 administration, while the latter may contribute to increased IgA production, leading to glomerular IgA deposition and progressive glomerulosclerosis in HIGA mice. The pathogenic role of T cell function and fluctuation of these subsets, especially the Th1/Th2 balance, is crucial to the immunopathological phenotype of the renal lesions in HIGA mice.

Adult-onset idiopathic nephrotic syndrome associated with pure diffuse mesangial hypercellularity.

Pure diffuse mesangial hypercellularity (DMH), in its primary form, is a relatively rare histological finding and few data exist in the literature regarding its clinical course and prognosis in nephrotic adults with this diagnosis. We retrospectively analysed the clinical and histological data of 28 adult nephrotic patients (13 male) with this diagnosis with regard to response to the treatment, outcome and prognostic indicators. Of 25 patients treated with prednisolone (Pred), nine (36%) showed complete remission (CR) of proteinuria, eight (32%) partial remission (PR) and eight (32%) did not respond at all (NR). The combination of cyclosporin treatment with prednisolone of those with PR or NR produced one further complete and two partial remissions. At the end of follow-up (mean 64 months), 10 patients (40%) were in CR, nine (36%) in PR and six (24%) were NR and remained nephrotic. Renal function remained unchanged in patients with CR or PR. In contrast, the six non-responders progressed to end-stage renal disease (ESRD). Compared with non-responders, patients who responded to Pred were older and had normal renal function at presentation. This group also had less mesangial sclerosis and severe tubulointerstitial fibrosis and none showed synechiae with Bowman's capsule. IgM mesangial deposits were observed in 22% of patients with CR in response to Pred, in 37% of those with PR and in 100% of non-responders, who finally progressed to ESRD. A multivariate analysis of clinical and histological features at biopsy showed persistent nephrotic syndrome (P<0.001), the severity of DMH (P<0.03) and the presence of mesangial IgM (P<0. 01) to have independent predictive value for ESRD. This analysis also demonstrated that only mesangial sclerosis (P<0.03) and the presence of mesangial IgM (P<0.002) independently predicted the response to therapy. DMH associated with idiopathic nephrotic syndrome is a heterogeneous entity. Patients who respond to therapy (completely or partially) have a benign course similar to that of minimal change nephrotic syndrome. They are usually older and have normal renal function at presentation, whereas 'sclerotic' lesions are less frequent findings in initial biopsies. Non-responders tend to be younger and progress to ESRD. Most of them have impaired renal function at first assessment and more prominent 'sclerotic' lesions on initial biopsies. Mesangial IgM is an independent marker of poorer response to treatment and progression to ESRD but it lacks specificity.

Predicting first-year relapses in children with nephrotic syndrome.

More than half of the children diagnosed with nephrotic syndrome will have relapses. These can be infrequent relapses (IRs: <2 in 6 months or <3 in a year) or frequent relapses (FRs: >2 in 6 months or >3 in a year). Patients who relapse while on alternate day steroids or within 1 month of discontinuation of steroid therapy are considered steroid-dependent (SD; J Pediatr. 1982; 101:514-518). Patients with an IR course have a better long-term prognosis, and many of them have minimal-change disease without mesangial hypercellularity or sclerosis. The purpose of our study was to identify factors at initial presentation that could predict the relapse pattern in the first year after diagnosis, without taking into consideration the histopathology found on renal biopsy. We analyzed the medical records of children who were seen by us before March 1997 and followed for at least 1 year. Variables selected in the study were age, sex, race, presence or absence of hematuria, and days to remission (defined as protein-free) at the initial presentation, because they could relate to the pattern of relapses (ie, IR, FR, and SD). Of 70 patients, 14 were excluded because of insufficient data. There were 38 males (67.9%) and 18 females (32.1%), giving a male:female ratio of 1.8:1. Median age at presentation was 3.25 years (range: 1.5-13), and 76.9% were white, 8.9% black, 7.1% Hispanic, and 7.1% other. Of all the patients, 23 were IR (41.1%), 9 were FR (16.1%), and 24 were SD (42. 9%). Median days to remission were 10 (range: 2-60), on Prednisone 60 mg/M(2) daily. Hematuria was present initially in 26 patients (46. 4%), and absent in 30 (53.6%). Age, sex, race, and hematuria, as independent variables, were not predictors of relapses in the first year. However, using a stratified analysis based on the presence or absence of hematuria, we found that if the remission occurred within the first week of therapy, the patients without hematuria were more likely to be IR. The sensitivity and specificity of this finding were 67% and 89%, respectively, with a positive predictive value of 94%. We conclude that of all the presenting features, the rapidity of initial response to steroid therapy combined with the presence of hematuria, could predict future relapses and should be well documented.

Living donor kidney transplants: a biopsy study 1 year after transplantation, compared with baseline changes and correlation to kidney function at 1 and 3 years.

Chronic changes in biopsies from long-term stable kidney allografts have been reported to correlate with graft prognosis. Morphological changes in baseline ('zero-hour') biopsies have been described as well, but their importance for long-term prognosis have been less clear. The aim of the present study was to evaluate biopsy changes from baseline to 1 year after transplantation in patients receiving kidneys from living donors, and to assess the possible prognostic implications of these findings. Light microscopical changes in 18 gauge full-core biopsies were scored semi-quantitatively in 33 patients 1 year after transplantation, and compared to baseline changes previously reported [1]. All cases were also examined with transmission electron microscopy. The semi-quantitative data from baseline and at 1 year were correlated with kidney function 1 and 3 years after transplantation. The reproducibility of baseline findings regarding arteriosclerosis and arteriolar hyalinosis was tested by comparison with biopsies 1 week after transplantation (n = 43). We found a significant increase in mesangial glomerular sclerosis (P<0.001), interstitial fibrosis/tubular atrophy (if/ta) (P = 0.002), and mononuclear cell interstitial infiltration (P = 0.003) after 1 year, compared to baseline changes. There was an increase of arteriosclerosis (P = 0.028) and arteriolar hyalinosis (P = 0.006) when compared to biopsies taken 1 week after transplantation, but not when compared to the 'zero-hour' findings. Electron microscopy revealed one case of recurrent immune-complex glomerulonephritis and another case of recurrent light chain deposition kidney disease. Comparing 1-week vascular findings with baseline gave a low level of reproducibility, probably due to sampling error. Baseline biopsy findings could not predict long-term kidney function. In the 1-year biopsy, if/ta was significantly correlated with serum creatinine (P = 0.007) and glomerular filtration rate (GFR) (P<0.001) at 1 year, with serum creatinine at 3 years (P = 0.011), and with the first-year cumulative dose of methylprednisolone (P = 0.004). Serum creatinine at 1 year, however, was found to be the most accurate predictor of 3-year kidney function (P<0.001). Donor age was correlated to kidney function at 3 years (P = 0.013) but not at 1 year after transplantation. Morphological changes in baseline biopsies of living donor kidneys tend to become more pronounced in well-functioning allografts during the first year after transplantation. In the 1 year biopsy, if/ta seems to be the most reliable variate for grading of chronic changes. However, 1-year serum creatinine predicted long-term kidney function more precisely than did the biopsy scores. Based on the results of the present study, a protocol 1-year biopsy does not seem warranted in the management of the graft recipient with a stable kidney function.