Clinical features and outcomes of focal segmental glomerulosclerosis pathologic variants in Korean adult patients

Aberrant localization of β1 integrin in podocyte cytoplasm of primary FSGS with cellular lesion

Podocyte detachment is a major trigger in pathogenesis of focal segmental glomerulosclerosis (FSGS). Detachment via β1 integrin (ITGB1) endocytosis, associated with endothelial cell injury, has been reported in animal models but remains unknown in human kidneys. The objectives of our study were to examine the difference in ITGB1 dynamics between primary FSGS and minimal change nephrotic syndrome (MCNS), among variants of FSGS, as well as between the presence or absence of cellular lesions (CEL-L) in human kidneys, and to elucidate the pathogenesis of FSGS. Thirty-one patients with primary FSGS and 14 with MCNS were recruited. FSGS cases were categorized into two groups: those with CEL-L, defined by segmental endocapillary hypercellularity occluding lumina, and those without CEL-L. The podocyte cytoplasmic ITGB1 levels, ITGB1 expression, and degrees of podocyte detachment and subendothelial widening were compared between FSGS and MCNS, FSGS variants, and FSGS groups with and without CEL-L (CEL-L( +)/CEL-L( -)). ITGB1 distribution in podocyte cytoplasm was significantly greater in CEL-L( +) group than that in MCNS and CEL-L( -) groups. ITGB1 expression was similar in CEL-L( +) and MCNS, but lower in CEL-L( -) compared with others. Podocyte detachment levels were comparable in CEL-L( +) and CEL-L( -) groups, both exhibiting significantly higher detachment than the MCNS group. Subendothelial widening was significantly greater in CEL-L( +) compared with CEL-L( -) and MCNS groups. The findings of this study imply the existence of distinct pathological mechanisms associated with ITGB1 dynamics between CEL-L( +) and CEL-L( -) groups, and suggest a potential role of endothelial cell injury in the pathogenesis of cellular lesions in FSGS.

Clinicopathological features and medium-term outcomes of histologic variants of primary focal segmental glomerulosclerosis in adults: A retrospective study

BACKGROUND

The Columbia classification identified five histological variants of focal segmental glomerulosclerosis (FSGS). The prognostic significance of these variants remains controversial.

AIM

To evaluate the relative frequency, clinicopathologic characteristics, and medium-term outcomes of FSGS variants at a single center in Pakistan.

METHODS

This retrospective study was conducted at the Department of Nephrology, Sindh Institute of Urology and Transplantation, Karachi, Pakistan on all consecutive adults (≥ 16 years) with biopsy-proven primary FSGS from January 1995 to December 2017. Studied subjects were treated with steroids as a first-line therapy. The response rates, doubling of serum creatinine, and kidney failure (KF) with replacement therapy were compared between histological variants using ANOVA or Kruskal Wallis, and Chi-square tests as appropriate. Data were analyzed by SPSS version 22.0. P-value ≤ 0.05 was considered significant.

RESULTS

A total of 401 patients were diagnosed with primary FSGS during the study period. Among these, 352 (87.7%) had a designated histological variant. The not otherwise specified (NOS) variant was the commonest, being found in 185 (53.9%) patients, followed by the tip variant in 100 (29.1%) patients. Collapsing (COL), cellular (CEL), and perihilar (PHI) variants were seen in 58 (16.9%), 6 (1.5%), and 3 (0.7%) patients, respectively. CEL and PHI variants were excluded from further analysis due to small patient numbers. The mean follow-up period was 36.5 ± 29.2 months. Regarding response rates of variants, patients with TIP lesions achieved remission more frequently (59.5%) than patients with NOS (41.8%) and COL (24.52%) variants (P < 0.001). The hazard ratio of complete response among patients with the COL variant was 0.163 [95% confidence interval (CI): 0.039-0.67] as compared to patients with NOS. The TIP variant showed a hazard ratio of 2.5 (95%CI: 1.61-3.89) for complete remission compared to the NOS variant. Overall, progressive KF was observed more frequently in patients with the COL variant, 43.4% (P < 0.001). Among these, 24.53% of patients required kidney replacement therapy (P < 0.001). The hazard ratio of doubling of serum creatinine among patients with the COL variant was 14.57 (95%CI: 1.87-113.49) as compared to patients with the TIP variant.

CONCLUSION

In conclusion, histological variants of FSGS are predictive of response to treatment with immunosuppressants and progressive KF in adults in our setup.

A Case Report on Primary Collapsing Glomerulopathy in a Filipino Post-partum Female and An Updated Review of Literature

Collapsing Glomerulopathy (CG) is a rare entity presenting as nephrotic syndrome and rapidly progressive renal deterioration. It has been first identified among African-American patients and subsequently dubbed HIV-associated nephropathy after a number of patients with HIV were found to have CG. It has re-emerged recently among patients with COVID-19. To our knowledge, this is the first case of primary collapsing glomerulopathy in the country to be published. The case is a 36-year-old Filipino female admitted due to bipedal edema which started 2 weeks post-partum. She has no comorbidities and social history was negative for illicit drug use. Initial work up showed hypoalbuminemia and diffuse hepatic disease on ultrasound. She was referred to a gastroenterologist where albumin infusion and paracentesis was done but with no improvement. She developed anasarca and was admitted. Paracentesis obtained minimal ascitic fluid. Serum ascites albumin gradient was low and baseline laboratories showed high creatinine, hypoalbuminemia, and albuminuria. 24-hour urine protein was 11 grams, ANA and anti-DsDNA were negative and c3 and c4 levels were normal. Hepatitis profile was negative for infection. Abdominal CT scan revealed multiple hypoenhancing lesions. Tumor markers CA-125, CA 19-9 and CA 15-3 were high. Breast ultrasound showed simple breast cyst. Gynecology consult was called where pap smear was negative for atypical cells. Surgery service recommended monitoring for the pancreatic and breast lesions. Kidney biopsy was delayed due to new onset bacterial pneumonia. COVID-19 RT-PCR test was negative. Patient was discharged improved with no edema. On follow up, the kidney biopsy result came out to be collapsing glomerulopathy. HIV test was then done and was negative. Bipedal edema and albuminuria recurred. She was started on tacrolimus. She has been on regular follow up and currently has no edema, no proteinuria and normal creatinine level. This is an interesting case as the primary glomerular disease has been masked by the earlier laboratory findings which led us to think of liver disease then a paraneoplastic nephrotic syndrome. Ultimately, the renal biopsy revealed the diagnosis. This serves as an index case for primary collapsing glomerulopathy in a Filipino patient on remission after being treated with tacrolimus.

The epidemiology of primary FSGS including cluster analysis over a 20-year period

INTRODUCTION

Focal segmental glomerulosclerosis (FSGS) is one of the leading causes of nephrotic syndrome in adults. This epidemiological study describes a renal centre's 20-year experience of primary FSGS.

METHODS

Patients were identified with a diagnosis of primary FSGS after exclusion of known secondary causes. In this retrospective observational study, data was collected for baseline demographics, immunosuppression and outcomes. A two-step cluster analysis was used to identify natural groupings within the dataset.

RESULTS

The total cohort was made up of 87 patients. Those who received immunosuppression had lower median serum albumin than those who did not- 23g/L vs 40g/L (p<0.001) and higher median urine protein creatinine ratios (uPCR)- 795mg/mmol vs 318mg/mmol (p <0.001). They were more likely to achieve complete remission (62% vs 40%, p=0.041), but relapsed more 48.6% vs 22% (p=0.027). Overall 5 year mortality was 10.3% and 5 year progression to RRT was seen in 17.2%. Complete remission was observed in 49.4%. The 2-step cluster analysis separated the cohort into 3 clusters: cluster 1 (n=26) with 'nephrotic-range proteinuria'; cluster 2 (n=43) with 'non-nephrotic-range proteinuria'; and cluster 3 (n=18) with nephrotic syndrome. Immunosuppression use was comparable in clusters 1 and 3, but lower in cluster 2 (77.8% and 69.2% vs 11.6%, p<0.001). Rates of complete remission were greatest in clusters 1 and 3 vs cluster 2: 57.7% and 66.7% vs 37.2%.

CONCLUSION

People who received immunosuppression had lower serum albumin and achieved remission more frequently, but were also prone to relapse. Our cluster analysis highlighted 3 FSGS phenotypes: a nephrotic cluster that clearly require immunosuppression; a cohort with preserved serum albumin and non-nephrotic range proteinuria who will benefit from supportive care; and lastly a cluster with heavy proteinuria but serum albumin > 30g/L. This group may still have immune mediated disease and thus could potentially benefit from immunosuppression.

TRIAL REGISTRATION

This study protocol was reviewed and approved by the 'Research and Innovation committee of the Northern Care Alliance NHS Group', study approval number (Ref: ID 22HIP54).

A Study of Focal and Segmental Glomerulosclerosis according to the Columbia Classification and Its Correlation with the Clinical Outcome

Introduction  Focal and segmental glomerulosclerosis (FSGS) is a leading cause of nephrotic syndrome in both adults and children. The "Columbia classification of FSGS" includes five variants; not otherwise specified (NOS), tip, perihilar, cellular, and collapsing variants that may have different prognostic and therapeutic implications. Materials and Methods  This is a retrospective study and was carried out in the Department of Histopathology, Apollo Hospitals, Hyderabad. Of a total of 11,691 kidney biopsies over a 7-year period, from 2006 to 2012, 824 cases were diagnosed as FSGS, of which 610 cases in which detailed clinical findings were available were included in this study. FSGS was then categorized according to the Columbia classification. Results  FSGS, NOS was the predominant histomorphological variant. Serum creatinine was significantly high in the collapsing variant, followed by NOS. Follow-up data was available for 103 cases,72.8% had complete remission, 10.6% had partial remission, and in 16.5 % there was no remission. Relapses were observed in 6.7% cases, two patients (1.9%) succumbed, and 4.8% cases progressed to chronic kidney disease. Conclusion  This study showed that perihilar variant was less prevalent, with tip and cellular variants being more prevalent in Indian subcontinent compared to Western literature. Collapsing variant was also less common.

Clinical Course of Adult FSGS and Minimal Change Disease in North American and Japanese Cohorts

Key Points

Data from different geographical regions highlighted the differences in clinical manifestations and treatment response of adult FSGS/minimal change disease. There were shared factors that were associated with treatment response across the cohorts: FSGS, higher BP, and lower eGFR. Recognizing geographical difference allows us better understanding of disease biology, risk prediction, and design of future clinical trials.

Background

Regional differences in presentation and clinical course of nephrotic syndrome (NS) have not been studied well because few studies directly compared the data from different intercontinental regions.

Methods

We included adult nephrotic patients with FSGS and minimal change disease (MCD) who received immunosuppressive therapy (IST) in a North American (Nephrotic Syndrome Study Network [NEPTUNE], N =89) or Japanese (Nagoya Kidney Disease Registry [N-KDR], N =288) cohort. Baseline characteristics and rates of complete remission (CR) were compared. Factors associated with time to CR were evaluated by Cox regression models.

Results

NEPTUNE participants had more FSGS (53.9 versus 17.0%) and family history of kidney disease (35.2 versus 3.2%). N-KDR participants were older (median 56 versus 43 years) and demonstrated greater levels of urine protein creatinine ratio (7.73 versus 6.65) and hypoalbuminemia (1.6 versus 2.2 mg/dl). N-KDR participants showed higher proportion of CR (overall: 89.2 versus 62.9%; FSGS: 67.3 versus 43.7%; MCD: 93.7 versus 85.4%). A multivariable model showed that FSGS (versus MCD: hazard ratio [HR], 0.28; 95% confidence interval [CI], 0.20 to 0.41), systolic BP (per 10 mm Hg: HR, 0.93; 95% CI, 0.86 to 0.99), and eGFR (per 10 ml/min per 1.73 m2: HR, 1.16; 95% CI, 1.09 to 1.24) were associated with time to CR. There were significant interactions in patient age (P = 0.004) and eGFR (P = 0.001) between the cohorts.

Conclusions

The North American cohort had more FSGS and more frequent family history. Japanese patients showed more severe NS with better response to IST. FSGS, hypertension, and lower eGFR were shared predictors of poor treatment response. Identifying shared and unique features across geographically diverse populations may help uncover biologically relevant subgroups, improve prediction of disease course, and better design future multinational clinical trials.

Predictors of long-term outcomes in pediatric focal segmental glomerulosclerosis

BACKGROUND

Available data on primary focal segmental glomerulosclerosis (FSGS) in children usually report on short follow-up and small samples. Furthermore, the application of the Columbia classification for FSGS in children has not yet been fully agreed. We aimed to confirm the prognosis and risk factors of FSGS in a large cohort of Chinese children.

METHODS

Two hundred seventy-four children with primary FSGS from a single center were enrolled from 2003 to 2018. Long-term renal survival and related risk factors were evaluated by the Kaplan-Meier method and Cox multivariate regression analysis. Receiver operating characteristic (ROC) curve analysis further tested the effect of various risk factors in predicting renal outcomes. The composite end-point included ≥ 50% reduction in estimated glomerular filtration rate and/or end-stage renal disease or death.

RESULTS

One hundred twenty-five children were diagnosed with not otherwise specified (NOS) (45.6%) variant; 79 with tip lesions (28.8%), 32 with collapsing (11.7%), 31 with cellular (11.3%), and 7 with perihilar lesions (2.6%). The renal survival rate was 80.73% at 5 years, 62.58% at 10 years and 34.66% at 15 years. Multivariate analysis showed that chronic tubulointerstitial damage ≥ 25% (HR 4.14, 95% CI 1.49-11.50, P < 0.01), collapsing variant [(reference: NOS) HR 2.16, 95% CI 1.10-4.27, P = 0.03], segmental sclerosis (HR 1.03, 95% CI 1.01-1.04, P < 0.01) and age at biopsy (HR 0.91, 95% CI 0.85-0.98, P = 0.01) were significantly associated with renal outcomes. ROC curve analysis showed an excellent diagnostic yield of the Columbia classification. The combination of Columbia classification, CTI ≥ 25% and segmental sclerosis had the best predictive value for renal outcomes (AUC = 0.867, sensitivity = 77.78%, specificity = 82.27%, P < 0.01).

CONCLUSIONS

This study reports a renal survival rate of Chinese children with FSGS of 62.58% at 10 years and 34.66% at 15 years. Prognosis is poorer in patients with collapsing variant or CTI ≥ 25% and good in patients with tip variant. The Columbia classification is confirmed as a valuable tool for predicting prognosis of Chinese children with FSGS.

Clinical, Pathological, and Genetic Characteristics in Patients with Focal Segmental Glomerulosclerosis

Background

Approximately 30% of children with steroid-resistant nephrotic syndrome (SRNS) have causative monogenic variants. SRNS represents glomerular disease resulting from various etiologies, which lead to similar patterns of glomerular damage. Patients with SRNS mainly exhibit focal segmental glomerulosclerosis (FSGS). There is limited information regarding associations between histologic variants of FSGS (diagnosed using on the Columbia classification) and monogenic variant detection rates or clinical characteristics. Here, we report FSGS characteristics in a large population of affected patients.

Methods

This retrospective study included 119 patients with FSGS, diagnosed using the Columbia classification; all had been referred to our hospital for genetic testing from 2016 to 2021. We conducted comprehensive gene screening of all patients using a targeted next-generation sequencing panel that included 62 podocyte-related genes. Data regarding patients' clinical characteristics and pathologic findings were obtained from referring clinicians. We analyzed the associations of histologic variants with clinical characteristics, kidney survival, and gene variant detection rates.

Results

The distribution of histologic variants according to the Columbia classification was 45% (n=53) FSGS not otherwise specified, 21% (n=25) cellular, 15% (n=18) perihilar, 13% (n=16) collapsing, and 6% (n=7) tip. The median age at end stage kidney disease onset was 37 years; there were no differences in onset age among variants. We detected monogenic disease-causing variants involving 12 of the screened podocyte-related genes in 34% (40 of 119) of patients. The most common genes were WT1 (23%), INF2 (20%), TRPC6 (20%), and ACTN4 (10%). The perihilar and tip variants had the strongest and weakest associations with detection of monogenic variants (83% and 0%, respectively; P<0.001).

Conclusions

We revealed the distributions of histologic variants of genetic FSGS and nongenetic FSGS in a large patient population. Detailed data concerning gene variants and pathologic findings are important for understanding the etiology of FSGS.

Diverse alterations of glomerular capillary networks in focal segmental glomerulosclerosis

Introduction

Focal segmental glomerular sclerosis (FSGS) is caused by podocyte injury. It is characterized by obliteration of glomerular capillary tufts with increased extracellular matrix (ECM). Altered communication between podocytes and glomerular endothelial cells (ECs) contributes to sclerosis progression. We focused on EC injury in the FSGS.

Methods

A total of 29 FSGS and 18 control biopsy specimens were assessed for clinicopathologic characteristics. CD34 (a marker for EC)-positive capillaries and ECM accumulation were evaluated quantitatively for each variant using computer-assisted image analysis.

Results

The estimated glomerular filtration rate (eGFR) in the FSGS group was significantly lower than that in the control group. The frequency of FSGS variants was 51.7% for cellular; 13.8% for perihilar (PH), tip, and not otherwise specified (NOS); and 6.9% for collapsing. Regarding sclerotic lesions in all FSGS, narrowing or loss of CD34-positive capillaries was observed. Electron microscopy results showed loss of fenestrae, subendothelial space enlargement, and cytoplasmic swelling, indicating EC injury. Computer-assisted image analysis revealed significantly smaller areas of glomerular capillaries in FSGS with or without sclerotic lesions, with increased ECM. Moreover, in comparison with each variant, narrowed capillaries and ECM accumulation were most prominent in the collapsing variant, whereas the tip variant had the least change.

Conclusion

EC injury was observed in all FSGS cases, not only in sclerotic lesions but also in nonsclerotic lesions. Severity of EC injury may vary in each variant due to diverse alterations of glomerular capillary networks.

Glomerular Diseases in the Colombian Caribbean: Data from the Colombian Nephropathy Registry (NEFRORED®)

Our study aimed to describe the glomerular diseases, both primary glomerular disease (PGD) and secondary glomerular disease (SGD) in the Colombian Caribbean based on the first regional Colombian Nephropathy Registry (NEFRORED®). A descriptive and retrospective study of adult patients with glomerular diseases from the Colombian Caribbean region was made. All diagnoses by renal biopsy with light microscopy and immunofluorescence obtained between January 2008 and June 2018 were recorded. Eight hundred and seventy-one renal biopsies were obtained. The main clinical indication for biopsy was nephritic syndrome (36%). SGD was more frequent than PGD (55% vs. 45%). Within SGD group, lupus nephritis (LN) was the most frequent etiology (83%). Within PGD group, membranous nephropathy (33%) and focal segmental glomerulosclerosis (FSGS) (19%) were the most common glomerular diseases. At a 24-month follow-up, the patients with FSGS and paraproteinemia-mediated glomerular disease had the worst renal survival prognosis. This is the first Colombian Nephropathy Registry in a Caribbean population, demonstrating a high predominance of SGD due to LN.

Focal segmental glomerulosclerosis histologic variants and renal outcomes based on nephrotic syndrome, immunosuppression, and proteinuria remission

BACKGROUND

The associations of focal segmental glomerulosclerosis (FSGS) histologic variants with renal outcomes have rarely been investigated comprehensively by clinically relevant subgroups in this modern age.

METHODS

Data on 304 (173 nephrotic and 131 non-nephrotic) patients with biopsy-confirmed FSGS from 2010 to 2013 were analyzed using the Japanese nationwide renal biopsy registry. The primary outcome was a composite of a 30% decline in estimated glomerular filtration rate or progression to end stage kidney disease 5 years from the biopsy. We compared outcomes of FSGS variants according to the Columbia classification using survival analyses. Subgroup analyses were performed based on nephrotic syndrome (NS), immunosuppression, and proteinuria remission (PR, proteinuria <0.3 g/day) during follow-up. Additionally, associations of NS, immunosuppression, and PR with outcomes were examined for each variant.

RESULTS

The distribution of variants was 48% (n = 145) FSGS not otherwise specified (NOS), 19% (n = 57) tip, 15% (n = 47) perihilar, 13% (n = 40) cellular, and 5% (n = 15) collapsing. The outcome event occurred in 87 patients (29%). No significant differences in the outcome were found among the variants. Subgroup analyses yielded similar results. However, there was a trend toward improved outcome in patients with PR irrespective of variants (hazard ratio adjusted for histologic variant and potential confounders [adjusted HR]: 0.19 [95% confidence interval (CI), 0.10-0.34]). NS was marginally associated with better outcome compared with non-NS (adjusted HR: 0.50 [95% CI, 0.25-1.01].

CONCLUSIONS

FSGS variants alone might not have significant impacts on the renal outcome after 5 years, while PR could be predictive of improved renal prognosis for any variant. Specific strategies and interventions to achieve PR for each variant should be implemented for better renal outcomes.

Nephrotic syndrome with focal segmental glomerular lesions unclassified by Columbia classification; Pathology and clinical implication

Background

The Columbia classification is widely used for diagnosis of focal segmental glomerulosclerosis (FSGS). In practice, we occasionally encounter segmental glomerular lesions unclassified as Columbia classification. We analyzed the clinical implication of unclassified segmental lesions comparing with Columbia-classified FSGS.

Methods

A retrospective cohort study from 13 local hospitals in Japan. From 172 biopsy cases diagnosed with FSGS or minimal change disease (MCD)/FSGS spectrum with unclassified segmental lesions, adult patients with nephrotic syndrome who received immunosuppressive therapies were included. The cases are classified by pathology, i.e., typical FSGS lesions sufficiently classified into subgroups of Columbia classification: collapsing (COL), tip (TIP), cellular (CEL), perihilar (PH), and not otherwise specified (NOS), and unclassified by the Columbia classification into three subgroups: “endothelial damage,”; “simple attachment,”; and “minor cellular lesion,”. The response to immunosuppressive treatment and 30% decline of eGFR were compared.

Results

Among 48 eligible cases, all were Japanese, 34 were typical FSGS; 13 TIP, 15 CEL, 6 NOS, and no COL or PH cases. Fourteen were unclassified cases: endothelial damage (n = 6), simple attachment (n = 5), and minor cellular lesion (n = 3). The median age of overall patients was 60 years old and the median of eGFR and urinary protein creatinine ratio was 51.5 mL/min/1.73m² and 7.35, respectively. They received similar therapeutic regimen. Kaplan-Meier analysis revealed no significant difference in treatment response between typical FSGS and unclassified cases. Evaluating among the subgroups, endothelial damage, simple attachment and minor cellular lesion showed similar treatment response to TIP or CEL. No significant difference was also observed in the 30% decline of eGFR.

Conclusions

Japanese adult patients with nephrotic syndrome showing unclassified segmental lesions as Columbia classification may be equivalent clinical impact as Columbia classification of FSGS.

Autoimmunity in Focal Segmental Glomerulosclerosis: A Long-Standing Yet Elusive Association

Focal segmental glomerulosclerosis (FSGS) is a histological term that describes a pathologic renal entity affecting both adults and children, with a wide array of possible underlying etiologies. Podocyte damage with scarring, the hallmark of this condition, leads to altered permeability of the glomerular barrier, which may result in massive proteinuria and relentless renal function deterioration. A definite cause of focal segmental glomerulosclerosis can be confirmed in a minority of cases, while most forms have been traditionally labeled as primary or idiopathic. Despite this definition, increasing evidence indicates that primary forms are a heterogenous group rather than a single disease entity: several circulating factors that may affect glomerular permeability have been proposed as potential culprits, and both humoral and cellular immunity have been implicated in the pathogenesis of the disease. Consistently, immunosuppressive drugs are considered as the cornerstone of treatment for primary focal segmental glomerulosclerosis, but response to these agents and long-term outcomes are highly variable. In this review we provide a summary of historical and recent advances on the pathogenesis of primary focal segmental glomerulosclerosis, focusing on implications for its differential diagnosis and treatment.

Utility of Columbia classification in focal segmental glomerulosclerosis: renal prognosis and treatment response among the pathological variants

BACKGROUND

The utility of the Columbia classification (Col-class) for focal segmental glomerulosclerosis (FSGS) has not yet been fully proven.

METHODS

We extracted 201 FSGS patients from 10 nephrology centers in Japan and investigated the difference of a composite renal endpoint, defined as doubling of serum creatinine and/or development of end-stage renal disease, in pathological variants. Sensitivity analysis was used to prove the utility of the Col-class to predict renal outcomes. Additionally, the renal protective effects of steroids and/or immunosuppression (steroid/IS) were investigated in patients stratified according to the Col-class.

RESULTS

The patients were classified into the following variants: not otherwise specified [NOS; n = 121 (60.1%)], perihilar [n = 31 (15.4%)], cellular [n = 19 (9.5%)], tip [n = 17 (8.5%)] and collapsing [n = 13 (6.5%)]. No tip variant patients reached the renal endpoint. The renal outcome in the collapsing variant was significantly poorer than that in the NOS [hazard ratio (HR) 3.71; P = 0.005]. In the sensitivity analysis, the area under the receiver operating characteristic curve for the renal endpoint was increased by adding Col-class to a model including common risk factors (P = 0.021). In a subgroup treated without steroid/IS, the outcome in the cellular variant was worse than that in the NOS (HR 5.10; P = 0.040) but the difference was not observed in the subgroup with steroid/IS (HR 0.54; P = 0.539).

CONCLUSIONS

The Col-class is useful to predict renal prognosis in Japanese patients with FSGS. In addition to good prognosis in the tip variant and poor in the collapsing variant, good clinical course in the cellular variant treated with steroid/IS was suggested.

Clinical presentation, treatment and outcome of focal segmental glomerulosclerosis in Far North Queensland Australian adults

AIM

The aim is to describe the clinical features, treatment and outcomes in Australian adults with focal segmental glomerulosclerosis and identify predictors of disease progression and all-cause mortality.

METHODS

The study included all patients with biopsy confirmed focal segmental glomerulosclerosis between January 1997 and June 2014 at participating hospitals. Clinical factors, histopathological findings, biochemical markers and treatments were analysed and potential predictors of doubling serum creatinine, end stage kidney disease or death identified.

RESULTS

A total of 98 patients were included with a median follow up of 4.3 years. Thirty-four (35%) patients were Aboriginal or Torres Strait Islander. Focal segmental glomerulosclerosis not-otherwise-specified was the most common variant. Seventeen (59%) patients initially treated with immunosuppression experienced an improvement in renal function. At the end of follow up, 43 (44%) patients had progressed to the composite outcome. Baseline tubulointerstitial scarring and lower haemoglobin predicted shorter time to doubling serum creatinine. Dual diagnosis, higher serum creatinine, lower estimated glomerular filtration rate and doubling creatinine were associated with shorter time to end stage kidney disease with remission the only protective factor. Age was the only variable associated with all-cause mortality.

CONCLUSION

Focal segmental glomerulosclerosis holds serious implications for patients. Concomitant diabetic nephropathy, higher serum creatinine and lower estimated glomerular filtration rate at renal biopsy were associated with poorer renal prognosis. Indigenous people had a female predominance and are over-represented in relation to their population size, however, were not associated with poorer prognosis. Remission was the only modifiable variable and thus should be at the forefront of patient management goals and future studies.

Determination of the optimal target level of proteinuria in the management of patients with glomerular diseases by using different definitions of proteinuria

Proteinuria is a major determinant of adverse renal outcome, and its reduction slows renal progression in glomerular diseases. However, the optimal target of proteinuria in glomerular diseases is unclear, and discrepancies in the definition of proteinuria produce ambiguous findings. Here we investigated the optimal target of proteinuria by using different definitions of proteinuria. We analyzed 574 IgA nephropathy (IgAN), 175 membranous nephropathy (MGN), and 177 focal segmental glomerulosclerosis (FSGS) cases from 3 Korean kidney centers. We evaluated the impact of proteinuria on renal outcome with 2 definitions: time-average proteinuria (TAP) and time-varying proteinuria (TVP). The endpoint was renal progression, defined as a 50% decline in glomerular filtration rate or end-stage renal disease. During a median follow-up of 57.3 months, the primary outcome occurred in 54 patients with IgAN, 26 with MGN, and 30 with FSGS. Multivariate Cox regression using TAP indicated that there was a linear association between proteinuria and risk of renal progression in IgAN. However, moderate proteinuria was not associated with an increased risk of renal progression in MGN and FSGS. In contrast, the analysis by TVP showed that the risk significantly increased in proportion to proteinuria during follow-up in all 3 diseases. Our findings suggest that TVP-based model can delineate association between proteinuria and risk of renal progression better than TAP-based model, considering that TVP reflects the dynamic change of proteinuria over time. Thus, proteinuria reduction to the lowest possible level is required to improve renal outcomes in patients with glomerular diseases.

Pathogenesis of Focal Segmental Glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is characterized by focal and segmental obliteration of glomerular capillary tufts with increased matrix. FSGS is classified as collapsing, tip, cellular, perihilar and not otherwise specified variants according to the location and character of the sclerotic lesion. Primary or idiopathic FSGS is considered to be related to podocyte injury, and the pathogenesis of podocyte injury has been actively investigated. Several circulating factors affecting podocyte permeability barrier have been proposed, but not proven to cause FSGS. FSGS may also be caused by genetic alterations. These genes are mainly those regulating slit diaphragm structure, actin cytoskeleton of podocytes, and foot process structure. The mode of inheritance and age of onset are different according to the gene involved. Recently, the role of parietal epithelial cells (PECs) has been highlighted. Podocytes and PECs have common mesenchymal progenitors, therefore, PECs could be a source of podocyte repopulation after podocyte injury. Activated PECs migrate along adhesion to the glomerular tuft and may also contribute to the progression of sclerosis. Markers of activated PECs, including CD44, could be used to distinguish FSGS from minimal change disease. The pathogenesis of FSGS is very complex; however, understanding basic mechanisms of podocyte injury is important not only for basic research, but also for daily diagnostic pathology practice.

Idiopathic collapsing focal segmental glomerulosclerosis in an 81-year-old Japanese woman: a case report and review of the literature

Focal segmental glomerulosclerosis (FSGS) is classified into five variants, with the collapsing variant being the most rare. Collapsing FSGS is characterized by a black racial predominance and is often associated with human immunodeficiency virus-associated nephropathy. However, the number of idiopathic cases is increasing and the presentation of non-black patients becoming more routine. Our analysis of 15 previous reports investigating FSGS variants shows that the collapsing variant accounts for 10.6 % of FSGS cases and its average age of onset is 32 years old. The current case is one of the oldest cases of idiopathic collapsing FSGS identified, being an 81-year-old Japanese woman. She presented with severe renal insufficiency (serum creatinine 7.9 mg/dL, albumin 1.5 g/dL) and so underwent hemodialysis immediately. Urinalysis demonstrated 3+ proteinuria and 3+ hematuria and the serological work up was all negative. Renal biopsy showed wrinkling of capillary walls with collapse lumens in every glomerulus, without endothelial tubuloreticular inclusions. Combined treatment with steroids, cyclosporine and low-density lipoprotein apheresis increased urine output slightly but she was unable to withdraw from hemodialysis and died 3 months later. This variant is reported to have the highest rate of progression to end-stage renal disease, regardless of the therapeutic intervention. However, there are also examples of cases with partial or complete remission in the literature. Progressive cases, like the current case, seem to be difficult to induce remission in, so it is important to diagnose idiopathic collapsing FSGS at an early stage by performing a renal biopsy, even in elderly patients.

Study of glomerulonephritis evolution in Castilla-La Mancha (GLOMANCHA) between 1994 and 2008

BACKGROUND

Renal biopsy registries allow histopathological data to be collected to improve knowledge of different pathologies and their natural history.

AIM

To analyse the data of the Castilla La Mancha Glomerulonephritis Registry (GLOMANCHA) and the evolution of the different biopsy-proven pathologies between 1994 and 2008.

METHODS

The 6 most common biopsy-proven pathologies were collected during the 14 years of the study (941 biopsies) in the 5 participant centres of the autonomous community. In 2008, we assessed patient renal survival and mortality and we evaluated associated factors to each situation for each pathology.

RESULTS

Of the 941 biopsies, 59% belonged to men, with a mean age of 48±18 years. At the time of the biopsy, the median glomerular filtration rate was 50.3 (25.5-76.3) ml/min/1,73 m(2) and median proteinuria was 3.4 (1.5-6.4) grams per day. The most common pathology were lupus nephropathy, followed by focal segmental glomerulosclerosis and membranous nephropathy. Lupus nephropathy and minimal change disease achieved the best renal prognosis during follow-up (mean 7.3±4.8 years). Rapidly progressive glomerulonephritis type 3 and focal segmental glomerulosclerosis had the worst renal prognosis. In addition, rapidly progressive glomerulonephritis type 3 presented the worst vital prognosis.

CONCLUSIONS

In GLOMANCHA, we demonstrate the poor prognosis of rapidly progressive glomerulonephritis type 3, in contrast to minimal change disease or lupus nephropathy. Renal function is an independent predictor of renal survival and mortality in this study.