Focal And Segmental Glomerular Sclerosis Research Articles

Calcineurin inhibitors or cyclophosphamide in the treatment of membranous nephropathy superimposed with FSGS lesions: a retrospective study from China

Background Cyclophosphamide (CTX) and calcineurin inhibitors (CNIs) based regimens are recommended as immunosuppressive therapies for patients with idiopathic membranous nephropathy (IMN). Focal and segmental glomerular sclerosis (FSGS) lesions, which are common in membranous nephropathy (MN), are poor predictors of outcome. This study compared the differences of prognosis between two regimens in patients with IMN combined with FSGS lesions. Methods This retrospective study enrolled 108 patients with biopsy-proven IMN, accompanied with FSGS lesions, nephrotic syndrome and an estimated glomerular filtration rate (eGFR)≥60 mL/min/1.73 m2 who were treated with CTX or CNIs. We used propensity score matching (PSM) for balancing the confounding variables. Results During follow-up, 10 patients (10/55 [18.2%]; nine males) in the CNIs group showed a 50% decline in eGFR; eight had a not otherwise specified variant. Patients initially treated with CNIs had a significantly higher risk of progression to the primary outcome and a lower probability of complete or total remission. The relapse rate was higher in patients who initially received CNIs- than in those who received CTX-based treatment. Before PSM, age and 24-h urine protein level differed significantly between the groups. The PSM model included data from 72 patients. Worse outcomes were also noted among patients who initially received CNIs than those who received CTX-based treatments after matching. Conclusions Patients with MN combined with FSGS lesions have a higher risk of renal functional decline and a higher rate of relapse after CNIs than after CTX therapy.

#5124 GENETIC GLOMERULAR DISEASES IN THE ADULT PATIENT: A WORK IN PROGRESS – SINGLE CENTRE COHORT

Abstract Background and Aims Recent advances in genetic molecular techniques have allowed the expansion of knowledge in glomerular diseases of genetic cause, including the identification of genes involved in focal and segmental glomerular sclerosis (FSGS). The prevalence of adult-onset genetic FSGS varies widely depending on the population studied. In central Europe, NPHS2 and COL4A3, COL4A4 e COL4A5 genes are postulated to be the most frequent genes implicated in genetic causes of adult FSGS. This study aims to characterize patients submitted to genetic study of glomerular diseases in the Nephrogenetics Clinic of our centre. Method We conducted a single-centre retrospective analysis of the patients submitted to genetic study of glomerular diseases in the Nephrogenetics Clinic of our centre from 2016 to 2022. Adult patients with a glomerular disease phenotype suggestive of a genetic cause were studied, using a predetermined phenotype-targeted panel of genes, through massive parallel sequencing. The number of genes included in this panel has increased (from 21 genes in 2016 to 49 genes since 2018); given this change, patients with a negative result on the first approach repeated screening with the broader panel. Additionally, patients presenting with advanced chronic kidney disease (CKD) without an identifiable phenotype, studied with a larger panel for CKD causing genes, are reported. In patients with a negative result but highly suggestive presentation, whole exome sequencing (WES) was considered, after multidisciplinary discussion with a Geneticist's evaluation. Patients with variants of unknown significance (VUS) were referred to a Genetics’ consultation for genetic counselling and segregation studies. Results Of the 80 patients studied (comprising 74 families), 52.5% were female (n=42) and 79% (n=63) of Caucasian ascent. Mean age was 45.4 ± 16.0 years. Nine patients were studied with the larger gene panel for CKD. 85% (n=68) had CKD (all stages) at presentation, with proteinuria (ranging from sub-nephrotic to nephrotic range) and 15% had asymptomatic urinary changes. 50% (n=40) of patients had positive family history, and 31% (n=25) had a syndromic presentation and/or extra renal manifestations. 27.5% (n=22) had a renal biopsy, and the most prevalent result was FSGS (11%; n=9). Genetic variants were identified in 70% (n=56) of the patients; but pathogenicity is not fully established in all: genotype-phenotype correlations, including inheritance pattern and histological correlation, and segregation studies (when indicated and possible) are ongoing. In 5 patients results are pending. Pathogenic / likely pathogenic variants were identified in at least 47.5% (n=38) patients. The most frequently implicated genes were: COL4A3, COL4A4 e COL4A5 (n=21), high risk APOL1 (n=8); NPSH2 (n=5), IFN2 (n=6, 3 pathogenic, 1 variant of unknown significance (VUS), 2 under segregation studies) and MYH9 (n=3). COL4A3, COL4A4 e COL4A5 mutations occur with Alport syndrome, but also with histologically documented FSGS, sub-nephrotic and nephrotic proteinuria, nephrotic syndrome and asymptomatic urinary changes. In our cohort, NPHS2 p.R229Q was identified in 5 patients (6%), but only with pathogenic significance in 3 patients, and APOL1 high risk haplotype was co-identified with COL4 variants in 3 patients. Conclusion The genetic study of a cohort of patients suspected of genetic FSGS allowed the identification of genetic variants in the genes of interest in a high percentage of cases. The most frequently implicated genes were COL4A3, COL4A4 e COL4A5, NPHS2, INF2 and APOL1 high risk haplotype. The high percentage of gene variants identified in our cohort is probably due to the selection of a population with a high likelihood of genetic FSGS. Further studies will clarify the causal and/or modifier effect of some genes, namely COL4A3, COL4A4 e COL4A5. The future use of WES in cases of high likelihood of genetic cause will probably allow the identification on novel candidate genes and increase the clinical benefits of a genetic diagnosis of FSGS.

Frasier Syndrome: A Rare Disorder in a Patient With Nephrotic Syndrome

Frasier syndrome is a rare genetic disorder characterized by the association of progressive renal glomerulopathy, 46,XY complete gonadal dysgenesis with a high risk of developing gonadoblastoma. Mutations in the Wilms' tumor suppressor gene (WT1) located in 11p23 responsible for this syndrome. Patients with this syndrome commonly present with normal female genitalia, streak gonads, and 46, XY karyotyping. Nephropathy in Frasier syndrome conferred as a nephrotic syndrome (NS) with proteinuria that begins early in childhood and progressively increases with age, mainly due to nonspecific focal and segmental glomerular sclerosis (FSGS). We herein discuss a 4 year-old-girl who presented as a steroid-resistant nephrotic syndrome and later on diagnosed as a Frasier syndrome.

STUDY OF NR1I2 GENE POLYMORPHISM (A7635G) AND STEROID RESISTANCE IN EGYPTIAN CHILDREN WITH IDIOPATHIC NEPHROTIC SYNDROME

Nephrotic Syndrome (NS) is a common chronic disorder, characterized by alterations of the permeability of the glomerular capillary wall, resulting in its inability to restrict the urinary loss of protein. INS ( also called nephrosis ) is defined by the combination of a nephrotic syndrome (proteinuria, hypoalbuminemia, hyperlipidemia, and edema) and non-specific histological abnormalities of the kidney including minimal changes (MC), focal and segmental glomerular sclerosis (FSGS), and diffuse mesangial proliferation. As INS response to treatment with steroids varies. Several studies was done to analyze the correlation between steroid -related genes and the response to steroid treatment.The influence of polymorphisms on treatment response of children with INS was investigated. The results may be useful for predicting the treatment response of children with INS.. Nowadays it is clear that NR1I2 gene is also involved in regulation of intermediate metabolism through trans-activation and trans-repression of genes controlling glucose, lipid, cholesterol, bile acid, and bilirubin homeostasis. so it affects steroid drug metabolism and as a consequence the mutation of this gene may affect the response of NS children to treatment. valuable information in prognosis and pathology of the disease types.

Epigallocatechin-3-Gallate Attenuates Adriamycin-Induced Focal Segmental Glomerulosclerosis via Suppression of Oxidant Stress and Apoptosis by Targeting Hypoxia-Inducible Factor-1α/ Angiopoietin-Like 4 Pathway

Background: Focal and segmental glomerular sclerosis (FSGS) is a common cause of nephrotic syndrome and end-stage renal disease. It has been reported that overproduction of reactive oxygen species (ROS) and cell apoptosis are associated with the development of FSGS. Epigallocatechin-3-gallate (EGCG) is a bioactive constituent accounting for more than 50% of the total catechins in green tea, which have anti-oxidative and anti-apoptotic effects. Based on this, this study was designed to evaluate the renoprotective effect of EGCG treatment on Adriamycin-induced FSGS. ­Methods: In C57BL/6 mice, Adriamycin nephropathy (AN) was induced by Adriamycin (10 mg/kg body weight, diluted in normal saline) via a tail vein on day 0. Then the mice were given with EGCG (20 mg/kg body weight) or YC-1 (Lificiguat, a specific inhibitor of hypoxia-inducible factor-1α [HIF-1α], 50 mg/kg body weight) or both intraperitoneally. Both the EGCG and YC-1 were given on the day of Adriamycin injection and continued for 6 weeks. The animals were organized into the following 5 groups for the animal experiments: the control group, the AN group, the AN + EGCG group, the AN + YC-1 group and the AN + EGCG + YC-1 group. At 6 weeks, the mice were sacrificed; kidneys and blood samples were collected for further analysis. The HIF-1α and the angiopoietin-like 4 (ANGPTL4) expression were detected by Western blot, real-time PCR, immunohistochemistry or immunofluorescence. Dihydroethidium staining and NADPH oxidase 1 (Nox1) measurement were used to detect ROS production. Terminal deoxynucleotide transferase-mediated dUTP nick end-labeling (TUNEL) staining and caspase-3 measurement was used to detect cell apoptosis. Results: When the animals were treated with Adriamycin, both the ROS production and TUNEL positive cells increased. Besides, the expression of HIF-1α, ANGPTL4, and caspase-3 were also up-regulated, while EGCG treatment could attenuate these changes. Interestingly, compared with treatment with YC-1 or EGCG alone, more pronounced inhibition of ANGPTL4, caspase-3 and Nox1 were obtained when YC-1 and EGCG were administered simultaneously. Conclusion: EGCG attenuates FSGS through the suppression of Oxidant Stress and apoptosis by targeting the HIF-1α/ANGPTL4 pathway.

Focal segmental glomerular sclerosis: do not overlook the role of immune response

Focal and segmental glomerular sclerosis (FSGS) is a histological pattern characterized by the partial sclerosis of some, but not all, glomeruli. It may be secondary to diverse etiologies such as mutations of podocyte key genes, loss of nephrons, drugs, and virus infection. However, in most cases of FSGS, the etiology is unknown and these forms are called idiopathic (primary) FSGS. A number of different pathogenic hypotheses have been proposed. The frequent recurrence of nephrotic proteinuria after renal transplantation has attracted the attention to search for plasma factors eventually implicated in the pathogenesis. However a decisive and unifying hypothesis is still lacking. On the other hand, recent findings indicate the involvement of cellular immunity and possibly autoantibodies in the pathogenesis of some forms of FSGS. In this paper we report on the recent advances in the pathophysiology of idiopathic FSGS and suggest the possibility that at least some forms of idiopathic FSGS may be caused by autoimmune reactivity.

Frasier syndrome: four new cases with unusual presentations

Frasier syndrome (FS) is characterized by gonadal dysgenesis and nephropathy. It is caused by specific mutations in the Wilms' tumor suppressor gene (WT1) located in 11p23. Patients with the 46,XY karyotype present normal female genitalia with streak gonads, and have higher risk of gonadal tumor, mainly, gonadoblastoma. Therefore, elective bilateral gonadectomy is indicated. Nephropathy in FS consists in nephrotic syndrome (NS) with proteinuria that begins early in childhood and progressively increases with age, mainly due to nonspecific focal and segmental glomerular sclerosis (FSGS). Patients are generally unresponsive to steroid and immunosuppressive therapies, and will develop end-stage renal failure (ESRF) during the second or third decade of life. We report here four cases of FS diagnosis after identification of WT1 mutations. Case 1 was part of a large cohort of patients diagnosed with steroid-resistant nephrotic syndrome, in whom the screening for mutations within WT1 8-9 hotspot fragment identified the IVS9+5G>A mutation. Beside FS, this patient showed unusual characteristics, such as urinary malformation (horseshoe kidney), and bilateral dysgerminoma. Cases 2 and 3, also bearing the IVS9+5G>A mutation, and case 4, with IVS9+1G>A mutation, were studied due to FSGS and/or delayed puberty; additionally, patients 2 and 4 developed bilateral gonadal tumors. Since the great majority of FS patients have normal female external genitalia, sex reversal is not suspected before they present delayed puberty and/or primary amenorrhea. Therefore, molecular screening of WT1 gene is very important to confirm the FS diagnosis.

Non-diabetic renal diseases in diabetics

Abstract Diabetic nephropathy (DN) is a specific condition with a well-defined clinical course especially in type I diabetes. This is usually progressive and irreversible and does not have any specific treatment. But ‘diabetic nephropathy’ is not the only renal ailment found in diabetes. Renal conditions other than DN which are found in diabetics are collectively called non-diabetic renal disease. This is a heterogeneous mixture of glomerular and non-glomerular conditions. Although, some glomerulapathies were supposed to be more common in diabetics previously, a close review of various studies based on kidney biopsy, across the globe, suggests that the type and frequency of non-diabetic glomerular disease is dictated by indication of biopsy (proteinurea, hematurea, renal failure) and the underlying population studied. For example, in USA commonest lesion was focal and segmental glomerular sclerosis (FSGS), in Korea immunoglobulin A, in Iraq membranoproliferative glomerulonephritis (MPGN) and in India post infectious glomerulonephritis and interstitial nephritis. Ischemic nephropathy due to macrovascular diabetic complication, infections, chronic pyelonephritis, bladder dysfunction, obstructive uropathy, electrolyte abnormalities are common. Due to co-morbidities and various medications, episodes of acute kidney injury are also frequent. Many patients of primary renal diseases may develop drug-induced diabetes such as post transplant diabetes mellitus. Various conditions may co-exist with underlying DN. During evaluation of diabetic patients by nephrologist, a meticulous identification of all these non-diabetic renal conditions gives an opportunity to treat reversible conditions with specific therapy, help in renoprotection and helps in proper prognostication. A detailed classification of non-diabetic renal disease has been proposed for the benefit of clinicians.

RENAL BIOPSY FINDINGS IN BELGIUM: A RETROSPECTIVE SINGLE CENTER ANALYSIS

Renal biopsy is the definitive diagnostic test in patients with renal parenchymal disease. Renal biopsy registry is an important tool which can provide valuable data concerning early and correct epidemiological description and clinical correlations of renal diseases. Records of 326 adult renal biopsies performed at our hospital from January 1991 till the end of December 2006 were retrospectively examined.Overall, secondary glomerular diseases (SGD) were predominant (39.9%), followed by primary glomerular diseases (PGD) (30.4%), vascular diseases (13.2%) and TIN (6.7%). Total sclerosis of the kidney did not allow histopathological diagnosis in 5.8% of all biopsied kidneys. Focal and Segmental Glomerular Sclerosis (FSGS), IgA Nephropathy (IgAGN) and Minimal Change Disease (MCD) and Membranous Glomerulopathy (MGN) were the most common PGD, altogether representing 75.7% of all PGD. FSGS was the most frequent (30.3%), followed by IgAGN (21.2%), MCD (19.1%) and MGN in 15.1%.Vasculitis, HIVAN, diabetic nephropathy and amyloidosis were the most common SGD, altogether representing 90% of all SGD. Immune Mediated Glomerulonephritis (IMGN) were the most frequent (32.3%), followed by HIVAN (16.9%), diabetic nephropathy (14.6%) and amyloidosis (10%). Nephroangiosclerosis (benign and malignant nephroangiosclerosis) was the most frequent vascular nephropathy responsible for 79% of all vascular diseases. Thrombotic microangiopathy was seen in 9.3% and atherothrombotic disease in 7% of all vascular diseases.Concerning tubular diseases, chronic TIN accounted for 63.6% of all tubular diseases, followed by light chaincast nephropathy (22.7%) and acute TIN (13.6%). Becauseof lack of material, 3.4% of all biopsies could not be analyzed. These data demonstrate that the distribution of biopsy-proved renal diseases in a Belgian population of the Brussels area is strongly influenced by the indications of renal biopsy. Harmonization of these indications might reflect with more accuracy the actual incidence of different nephropathies in a given population.Nation and worldwide renal biopsy registers are important to follow patterns of renal diseases in different populations. This information is important not only for health organizations in order to plan health budget but also for helping clinicians to provide a better care to patients.

Tubular proteinuria in mice and humans lacking the intrinsic lysosomal protein SCARB2/Limp-2

Deficiency of the intrinsic lysosomal protein human scavenger receptor class B, member 2 (SCARB2; Limp-2 in mice) causes collapsing focal and segmental glomerular sclerosis (FSGS) and myoclonic epilepsy in humans, but patients with no apparent kidney damage have recently been described. We now demonstrate that these patients can develop tubular proteinuria. To determine the mechanism, mice deficient in Limp-2, the murine homolog of SCARB2, were studied. Most low-molecular-weight proteins filtered by the glomerulus are removed in the proximal convoluted tubule (PCT) by megalin/cubilin-dependent receptor-mediated endocytosis. Expression of megalin and cubilin was unchanged in Limp-2(-/-) mice, however, and the initial uptake of injected Alexa Fluor 555-conjugated bovine serum albumin (Alexa-BSA) was similar to wild-type mice, indicating that megalin/cubilin-dependent, receptor-mediated endocytosis was unaffected. There was a defect in proteolysis of reabsorbed proteins in the Limp-2(-/-) mice, demonstrated by the persistence of Alexa-BSA in the PCT compared with controls. This was associated with the failure of the lysosomal protease cathepsin B to colocalize with Alexa-BSA and endogenous retinol-binding protein in kidneys from Limp-2(-/-) mice. The data suggest that tubular proteinuria in Limp-2(-/-) mice is due to failure of endosomes containing reabsorbed proteins to fuse with lysosomes in the proximal tubule of the kidney. Failure of proteolysis is a novel mechanism for tubular proteinuria.

Frasier syndrome, a potential cause of end-stage renal failure in childhood

The diagnosis of Frasier syndrome is based on the association of male pseudohermaphroditism (as a result of gonadal dysgenesis), with steroid-resistant nephrotic syndrome due to focal and segmental glomerular sclerosis (FSGS), which progresses to end-stage renal failure (ESRF) during adolescence or adulthood. Frasier syndrome results from mutations in the Wilms' tumour suppressor gene WT1, which is responsible for alterations in male genital development and podocyte dysfunction. We describe the case of a 7-year-old girl who was referred to the paediatric emergency department with ESRF. Haemodialysis was started immediately because of severe hypertension and hyperkalaemia. In view of the fact that our patient had a past medical history of pseudohermaphroditism, we suspected that the acute presentation in ESRF may be related to a new diagnosis of Frasier syndrome. Our hypothesis was confirmed on examination of the medical records. There had been no medical follow-up for several years and, in particular, no renal imaging or functional assessment had ever been performed. This lack of surveillance explains why our patient presented with ESRF much earlier in this disease than expected and subsequently had to undergo kidney transplantation at a very young age.

Hepatitis B virus associated focal and segmental glomerular sclerosis: report of two cases and review of literature

The hepatitis B virus (HBV) is estimated to have infected about 350 million people worldwide, making it one of the most common human pathogens. Renal involvement is among its most common extra hepatic manifestations and usually manifests in the form of immune complex mediated glomerulopathy, such as membranous glomerulonephritis (MGN), membranoproliferative glomerulonephritis (MPGN), mesangioproliferative glomerulonephritis and immunoglobulin A (IgA) nephropathy. Occurrence of focal and segmental glomerular sclerosis (FSGS) with HBV infection is rare and only five cases have been reported earlier. We report two cases of hepatitis B associated FSGS. In both the cases, HBsAg was demonstrated in the renal tissue and both the cases showed response to treatment with lamivudine, thus indicating a possible causal association between the viral infection and occurrence of nephrotic syndrome.

Focal and segmental glomerular sclerosis (FSGS) in a man and a woman with Fabry’s disease

We describe a man and a woman with Fabry's disease. Renal biopsies showed late and early stages respectively of focal and segmental glomerulosclerosis (FSGS) and vascular changes. Clinically the hemizygous patient had advanced renal disease with nephrotic range proteinuria and serum creatinine 122 micromol/l. The female carrier had minimal albuminuria, borderline GFR with a normal serum creatinine, acroparesthesias, moderate fatigue, tinnitus and headache accompanied by ischemic cerebral lesions. Enzyme replacement therapy (ERT) was initiated according to our Fabry protocol, partly due to the renal morphologic findings. We conclude that FSGS and vascular changes may be an early morphologic finding in Fabry's disease, even in patients with subtle albuminuria. The potential role of FSGS as a marker of progressive renal disease in some Fabry patients is discussed. As FSGS and vascular changes obviously may exist across a wide range of clinical presentations and have potential prognostic implications, we suggest that a renal biopsy should be performed prior to enzyme replacement therapy in all adult Fabry patients with proteinuria of various levels. Efforts should be made to develop a scoring system to evaluate potential histologic markers. Protocol biopsies may have therapeutic implications and may provide valuable information in the evaluation of start and dosing of ERT.

Surgical management and genotype/phenotype correlations in WT1 gene–related diseases (drash, frasier syndromes)

Background/Purpose: The WT1 gene plays a role in urogenital and gonadal development. Germline mutations of this gene have been observed in patients with Drash or Frasier syndrome (Sd). The purpose of this report is to compare phenotype and genotype of these patients. Methods: Retrospective study of 12 patients treated since 1980 for WT1 gene–related disorders was conducted. Results: End-stage renal disease (ESRD) occurred in 9 patients, mostly because of diffuse mesangial sclerosis (DMS) or focal and segmental glomerular sclerosis (FSGS). Seven patients underwent kidney transplantation, and 2 died. Eleven tumors occurred: 8 Wilms' tumors, one soft tissue tumor, one bladder papilloma, and one gonadoblastoma. Wilms' tumors occurred at a younger age than expected. Eight patients had a 46,XY karyotype. One of these XY patients had female phenotype (Frasier syndrome); she was raised as a girl with bilateral gonadectomy. Seven XY patients had ambiguous phenotype; 4 have been raised as boys and 3 as girls. Four patients had a 46,XX karyotype; they had female genitalia and were raised as girls. WT1 gene analysis was performed in 10 patients and showed heterozygous germline mutations in exon 9 (n = 6), intron 9 (n = 1), exon 3 (n = 1), exon 4 (n = 1), or exon 7 (n = 1). Conclusions: ESRD was secondary to DMS when exon 9 was mutated, and secondary to FSGS when intron 9 was mutated. When exon 3, 4, and 7 were mutated, no nephropathy has been observed. Wilms' tumors occurred with any kind of WT1 mutation except intron 9. Abnormal sexual differentiation has been observed in all XY patients with WT1 mutation, and the most profound inversion of phenotype was observed with mutation in intron 9. Correlation between phenotype and genotype provides better understanding of the role of WT1, and can help the surgeon in the management of these patients. J Pediatr Surg 38:124-129. Copyright 2003, Elsevier Science (USA). All rights reserved.

Modulation of glomerular hypertension defines susceptibility to progressive glomerular injury

The fawn-hooded rat constitutes a spontaneous model for chronic renal failure with early systemic and glomerular hypertension, proteinuria (UpV) and high susceptibility to development of focal and segmental glomerular sclerosis (FGS). It has been argued that uninephrectomy (UNX) accelerates the development of glomerular injury by aggravation of glomerular hypertension and by an independent effect to promote glomerular enlargement. The present study was performed to further delineate the importance of these parameters for the development of FGS. At the age of eight weeks male rats were UNX and randomly assigned to either control (CON), enalapril (ENA) or Nw-nitro L-arginine methyl ester (NAME) treatment. In all groups glomerular hemodynamic studies were performed four weeks post-UNX. Systemic blood pressure and UpV were monitored for 4 to 12 weeks post-UNX. Kidneys were then prepared for morphologic study. ENA treatment achieved control of both systemic and glomerular hypertension, maintenance of glomerular hyperfiltration and hyperperfusion, increased ultrafiltration coefficient(Kf), and long-term protection against UpV and FGS. NAME rats showed aggravation of both systemic and glomerular hypertension, decreased renal perfusion and filtration with reduced Kf, and high filtration fraction. The incidence of FGS in NAME and CON groups was similar at 8 and 12 weeks post-UNX, respectively. Glomerular enlargement was present in CON and ENA rats, but did not correlate with injury, while glomerular tuft size was lowest in NAME rats, which displayed prominent glomerular injury. Systemic blood pressure correlated strongly with glomerular capillary pressure. We conclude that systemic and glomerular hypertension govern the development of UpV and FGS.(ABSTRACT TRUNCATED AT 250 WORDS)

Focal segmental glomerular sclerosis, a type of intractable chronic glomerulonephritis, is a stem cell disorder.

The etiopathogenesis of focal and segmental glomerular sclerosis (FGS) remains unknown. Using a new animal model for FGS (FGS mouse), we demonstrate here that bone marrow transplantation from normal mice to FGS mice with a high grade of proteinuria (+ + +) ameliorates FGS, and that the transplantation of bone marrow cells or purified hemopoietic stem cells (HSCs) from FGS mice induces FGS in normal mice. These findings strongly suggest that FGS is a stem cell disorder; the abnormalities may be genetically programmed at the level of HSCs.

Relapsing nephrotic syndrome

Relapsing nephrotic syndrome is the most frequent form of idiopathic nephrotic syndrome in children. Children with relapsing nephrotic syndrome respond to corticosteroids but relapse when corticosteroid dosage is decreased or soon after it is stopped. Idiopathic nephrotic syndrome is defined by the association of a nephrotic syndrome and minimal changes on renal biopsy with foot process fusion of epithelial cells on electron microscopy. No immunoglobulin or complement fraction deposits are seen on immunofluorescence examination.’ Patients with minimal change disease most often respond to corticosteroids. As renal biopsy is not usually performed when the patient responds to corticosteroids, minimal change disease (MCD) has become synonymous with steroid sensitive nephrotic syndrome. However, in some patients, histological examination shows diffuse mesa&al proliferation and/or focal and segmental glomerular sclerosis (FSGS). In addition, IgM deposits are frequently found. Several authors believe that MCD is a distinct disease and that diffuse mesangial proliferation, FSGS and IgM nephropathy are also distinct entities. There is no doubt that patients with diffuse mesangial proliferation or FSGS are more frequently resistant to corticosteroids and have a significant propensity for progression to renal failure. However, there is an overlap between these histological variants and a significant proportion of patients with FSGS respond to corticosteroids, whereas some patients with MCD are resistant to corticosteroids.’ Experience has shown that response to steroid therapy carries a greater prognostic weight than the histological features seen on the initial biopsy. Therefore, two types of nephrosis can be described

Cyclosporine in idiopathic nephrotic syndrome.

Idiopathic nephrotic syndrome encompasses two main forms of glomerular diseases, minimal change nephropathy and focal segmental glomerulosclerosis. Minimal change nephropathy is a disease of children which generally responds to corticosteroids. After remission, however, many patients show frequent relapses or steroid dependency. In these patients, cyclosporine may obtain remission of proteinuria in 80% of cases, although relapse usually occurs when the drug is stopped. Focal glomerulosclerosis is generally resistant to corticosteroids. Under cyclosporine some 40% of patients may attain complete or partial remission of the nephrotic syndrome particularly if low-dose prednisone is associated. Relapse of proteinuria usually occurs after stopping the drug. As cyclosporine may expose to chronic nephrotoxicity some guidelines should be followed to prevent this complication: - the doses should not exceed 5 mg/Kg/day - they should be adjusted whenever an increase in plasma creatinine of > or = 30% over the baseline values occurs - treatment should be stopped if there is no response within 3 months - a careful monitoring of patient under the supervision of a clinician trained with the use of cyclosporine is necessary. The term idiopathic nephrotic syndrome (INS) defines the association of a nephrotic syndrome with non specific glomerular lesions, in the absence of immune complex deposition (1). On the basis of renal histology two main types of INS are recognized: minimal change nephropathy (MCN) and focal and segmental glomerular sclerosis (FSGS).

AIDS-related glomerulopathy: Occurrence in specific risk groups

The histopathology and incidence of AIDS-related glomerulopathy was evaluated by renal biopsy (N = 24) or at autopsy in 159 patients, including 131 adults and 28 infants and children with AIDS. Thirty-five patients had overt clinical manifestations of renal disease characterized by a nephrotic syndrome with focal and segmental glomerular sclerosis (FSS). Fifteen patients had diffuse glomerular mesangial hyperplasia (MH) without or with minimal clinical renal disease and 109 had intact or minimally involved glomeruli. Whereas 15 of 30 (50%) i.v. drug users with AIDS had evidence of renal disease, only one of 53 (2%) homosexuals had clinical renal disease and only 6 (11%) had histologic evidence of glomerular pathology. The study confirms the important risk of i.v. drug use as a pathogenic factor of renal disease and shows a rarity of renal disease in homosexual or bisexual men with AIDS. On the other hand, 30% of adult Haitians with AIDS had FSS or diffuse MH, although i.v. drug use is not an important risk factor in this population. Moreover, eight of 28 (29%) children with perinatal AIDS had evidence of renal involvement, including four with a nephrotic syndrome and FSS. The data provide strong evidence for the existence of an AIDS-related glomerulopathy independent of i.v. drug use, but suggest that unrecognized co-factors may be important in the development of renal disease.