Tip Variant Research Articles

Postpartum Renal Cortical Necrosis: A Case Series

Rationale & ObjectivePostpartum renal cortical necrosis (postpartum RCN) is a severe form of obstetric acute kidney injury. This study aimed to identify clinicopathological features in Chinese postpartum RCN cases to determine how pathologic findings may contribute to the treatment and prognosis. Study DesignSingle-center, case series Setting & ParticipantsTwelve patients with postpartum RCN had kidney biopsies at Peking University First Hospital between 2014 and 2021. The diagnosis of postpartum RCN was made according to typical MRI or pathological features. Clinical, laboratory and pathological data were compared between patients with eGFR <30 (poor outcome) and ≥30 ml/min/1.73 m2 after six months. ObservationsAll postpartum RCN patients presented with stage 3 AKI attributed to a probable atypical hemolytic uremic syndrome. Pregnancy terminations occurred at a median gestational age of 35.5 weeks. Kidney biopsy was performed ranging 18 days to 4 months from delivery. Upon biopsy, hemoglobin, platelet count and LDH levels had been restored to 137 g/L, 214 ×109/L and 231.50±65.01 U/L, respectively. Four patients exhibited poor outcome, demonstrating higher schistocyte count, serum creatinine and mean arterial pressure at onset. Pathologically, glomerular segmental sclerosis was prevalent. The NOS variant was the most common type, followed by collapsing variant, cellular variant, and tip variant. Patients with poor kidney outcome had more glomerular coagulative necrosis, capillary thrombosis, extensive cortical coagulative necrosis, and pronounced arteriole/artery lesions including increased interlobular arteriole intimal edema and fibrin thrombosis, but a lower occurrence of segmental sclerosis. LimitationsLimited sample size and retrospective design. ConclusionsOur research has identified key pathological features in postpartum RCN patients with aHUS, highlighting the necessity for more effective therapeutic options. There is a clear demand for non-invasive biomarkers that can accurately track disease progression and inform treatment duration for long-term outcomes improvement.

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

The Columbia classification identified five histological variants of focal segmental glomerulosclerosis (FSGS). The prognostic significance of these variants remains controversial. To evaluate the relative frequency, clinicopathologic characteristics, and medium-term outcomes of FSGS variants at a single center in Pakistan. 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. 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. In conclusion, histological variants of FSGS are predictive of response to treatment with immunosuppressants and progressive KF in adults in our setup.

Five-Year study on renal outcomes in biopsy-proven focal segmental glomerulosclerosis patients in Shiraz, Iran.

Focal segmental glomerulosclerosis (FSGS) is a prevalent glomerular disease that often leads to nephrotic syndrome. It is characterized by consolidating a portion of the glomerular capillary tuft connected to Bowman's capsule. This retrospective cohort study aimed to determine the demographic characteristics, risk factors, and prognostic indicators associated with FSGS in Shiraz, Iran. The study included 53 primary FSGS patients aged over 18 years who were referred to clinics affiliated with Shiraz University of Medical Sciences. Data were collected through a comprehensive data-gathering sheet encompassing demographic information, medical history, laboratory test results, and histopathological findings. Statistical analysis was performed using SPSS 18, considering a significance level of p<0.05. A five-year follow-up was conducted on the 53 patients, with the mean age of 41.0±13.3 years. The most common FSGS variants observed were "not otherwise specified" (NOS, 13.2%) and tip variant (7.5%). Older patients exhibited higher disease activity, whereas remission rates were higher among younger individuals (P=0.012). Patients achieving remission had lower creatinine and Pro/Cr ratios and higher glomerular filtration rates (p<0.05). Treatment involving a combination of corticosteroids and mycophenolate mofetil showed a significant correlation with remission (P=0.036). Older patients with higher creatinine levels, higher Pro/Cr ratios, and lower glomerular filtration rates at disease onset may require more aggressive treatment. Combination therapy with mycophenolate mofetil and corticosteroids yields better outcomes, leading to increased remission rates. These findings provide valuable insights for managing FSGS patients.

Predictors of long-term outcomes in pediatric focal segmental glomerulosclerosis.

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. 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. 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 5years, 62.58% at 10years and 34.66% at 15years. 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). This study reports a renal survival rate of Chinese children with FSGS of 62.58% at 10years and 34.66% at 15years. 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.

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.

Long-term prognosis of primary focal segmental glomerulosclerosis in children

Objective: To investigate risk factors for the long-term prognosis of primary focal segmental glomerulosclerosis (FSGS) and associated with renal prognosis in children. Methods: A retrospective study was conducted by collecting clinical data including general information, clinical features and renal pathological findings of 124 children with primary FSGS in Department of Pediatrics of Jinling Hospital from January 2003 to December 2019. The cumulative renal survival rate was calculated by Kaplan-Meier survival analysis. The risk factors related to renal prognosis were identified by Cox regression risk model analysis and receiver operating characteristic (ROC) curve. Results: Among 124 children, 94 were males (75.8%) and 30 were females (24.2%). The children were 16 (14, 17) years of age at the time of kidney biopsies. There were 102 cases (82.3%) aged from 13 to 18 years. The period of follow-up was 64.8 (32.1, 86.0) months. There were 49 cases (39.5%) with nonspecific variant, 33 cases (26.6%) with tip variant, 22 cases (17.7%) with collapsing variant, 14 cases (11.3%) with cellular variant and 6 cases (4.8%) with periportal variant. The data of Kaplan-Meier survival analysis showed that cumulative renal survival rates of end-stage kidney disease (ESKD) or ≥50% decline in estimated glomerular filtration rate (eGFR) from baseline at the year of 5, 10 and 15 after renal biopsies were 66.9%, 51.4% and 21.0% respectively. Multivariate Cox regression analysis showed that hypertension, glomerular segmental sclerosis ratio, moderate to severe chronic tubulointerstitial lesions were independent risk factors for progressing to ESKD or ≥50% reduction in eGFR from baseline in pediatric FSGS (HR=5.28, 1.03, 7.81, 95%CI 2.77-10.05, 1.01-1.04, 4.08-14.98, all P<0.01). ROC curve analysis showed glomerular segmental sclerosis ratio (AUC=0.734, P<0.05, optimal cut-off value=25.4%, sensitivity=50.0%, specificity=88.6%), moderate and severe chronic renal tubulointerstitial lesions (AUC=0.724, P<0.05, sensitivity=46.3%, specificity=98.6%) had good efficacy in evaluating renal outcomes of FSGS. Conclusions: The long-term prognosis of FSGS in children is poor. The risk factors of poor prognosis in children with FSGS are hypertension, moderate to severe chronic renal tubulointerstitial lesions and glomerular segmental sclerosis (≥25.4%).

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

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. 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. 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). 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 Glomerular Sclerosis

IntroductionFocal 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.MethodsA 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.ResultsThe 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.ConclusionEC 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.

CLIP-170S is a microtubule+TIP variant that confers resistance to taxanes by impairing drug-target engagement.

Taxanes are widely used cancer chemotherapeutics. However, intrinsic resistance limits their efficacy without any actionable resistance mechanism. We have discovered a microtubule (MT) plus-end-binding CLIP-170 protein variant, hereafter CLIP-170S, which we found enriched in taxane-resistant cell lines and patient samples. CLIP-170S lacks the first Cap-Gly motif, forms longer comets, and impairs taxane access to its MT luminal binding site. CLIP-170S knockdown reversed taxane resistance in cells and xenografts, whereas its re-expression led to resistance, suggesting causation. Using a computational approach in conjunction with the connectivity map, we unexpectedly discovered that Imatinib was predicted to reverse CLIP-170S-mediated taxane resistance. Indeed, Imatinib treatment selectively depleted CLIP-170S, thus completely reversing taxane resistance. Other RTK inhibitors also depleted CLIP-170S, suggesting a class effect. Herein, we identify CLIP-170S as a clinically prevalent variant that confers taxane resistance, whereas the discovery of Imatinib as a CLIP-170S inhibitor provides novel therapeutic opportunities for future trials.

MO294COMPARISON OF TIP AND CELLULAR VARIANT OF PRIMARY FOCAL SEGMENTAL GLOMERULOSCLEROSIS

Abstract Background and Aims After membranous nephropathy, focal segmental glomerulosclerosis (FSGS) is the most common cause of nephrotic syndrome in European population. According to Columbia classification, there are five histological variants of FSGS defined on light microscopy (tip, cellular, perihilar, collapsing and not otherwise specified - NOS) and this classification has a prognostic significance. The aim is to compare features and outcomes of tip and cellular variant of primary FSGS. Method All patients with FSGS were identified by a retrospective review of the Registry of kidney biopsies at the Department of Nephrology and Dialysis, Dubrava University Hospital, Zagreb, from 2003 until 2020. Each kidney specimen was analyzed by light, immunofluorescent and electron microscopy and Columbia classification was applied by experienced nephropathologist. Patients with primary FSGS met following criteria: full nephrotic syndrome and diffuse podocyte foot process effacement in absence of secondary causes of FSGS. Laboratory findings were obtained for every patient at the time of biopsy and following outpatient visits. Complete remission was defined as proteinuria &amp;lt; 0.3 g/day with normal kidney function and partial remission as proteinuria 0.3 - 3.5 g/day. Variables are expressed as median ± IQR (interquartile range) and frequencies. Statistical comparison between groups of patients with tip and cellular variant of primary FSGS and disease outcome analysis were done. Results Out of 200 patients with FSGS, 59 (29.5 %) had primary form of disease. Tip variant was the most common form of primary FSGS (22 patients, 37 %) followed by NOS (20, 34 %), cellular (13, 22 %), perihilar (2, 3.5 %) and collapsing (2, 3.5 %) variant. Demographic and clinical features with initial laboratory findings are shown in Table 1. There were no significant differences between two groups in all analyzed variables in Figure 1. All patients were treated by anti-RAAS agents and steroids. Median follow-up was 55 months (range 1 – 196 months), and followup data were unavailable for three patients. Figure 2 shows treatment regimens in both patient grouos with treatment outcomes. Remission rate was significantly higher in tip variant (90 % vs. 41 %, p = 0.002). There was no difference in relapse rate between the two groups (p = 0.717). Conclusion There were no significant differences in clinical features and laboratory findings at the time of clinical presentation between tip and cellular variant of primary FSGS. Patients with tip variant had significantly higher remission rate than patients with cellular variant.

Autosomal Recessive Congenital Ichthyosis and Steroid-Resistant Nephrotic Syndrome due to Homozygous Mutation in the ALOX12B gene: A Novel Association with Review of Literature.

Nephrotic syndrome (NS) associated with autosomal recessive congenital ichthyosis (ARCI) is a rare association. In this article, we described a 4-year-old boy with steroid-resistant NS (SRNS) who had a history of ichthyotic skin lesions since birth. Renal biopsy revealed focal segmental glomerulosclerosis (tip variant). The skin biopsy was consistent with the findings of ichthyosis. Next-generation sequencing revealed a homozygous pathogenic variant (c.1625_1626del) in the exon 12 of the ALOX12B gene, confirming the diagnosis of ARCI2. The ALOX12B gene belongs to the lipoxygenase family and has a pivotal role in the formation of lipid layers in the epidermis. Leukotrienes have a counter-regulatory effect within the inflamed glomeruli, which influences the vascular tone and glomerular basement membrane permeability, that can be implicated in the pathogenesis of the NS. This child is currently in remission, on tacrolimus and low-dose prednisolone, with emollients and is on regular follow-up. SRNS associated with congenital ichthyosis secondary to a mutation in the ALOX12B gene has never been reported so far. The knowledge regarding this novel association will help the treating physicians in diagnosing this condition early, which will enable proper genetic counseling and prognostication of the disease to the family.

Immunoglobulin G/albumin staining in tubular protein reabsorption droplets in minimal change disease and focal segmental glomerulosclerosis.

Some renal biopsies cannot distinguish minimal change disease (MCD) from primary focal segmental glomerulosclerosis (FSGS) because of inadequate sampling and/or a lack of sampled glomeruli with segmental sclerosis. As protein excretion in MCD has been described as being albumin-selective, we examined whether the ratio of immunoglobulin G (IgG)/albumin staining in protein reabsorption droplets (tPRD) might help distinguish MCD from FSGS. Frozen tissue from 144 native renal biopsies from patients with nephrotic syndrome and a diagnosis of MCD or FSGS [73 MCD, 30 FSGS tip variant (FSGS-tip), 38 FSGS-not otherwise specified (FSGS-NOS), 3 FSGS collapsing] was retrospectively stained by direct immunofluorescence for IgG and albumin; none of these samples showed diagnostic lesions of FSGS. IgG and albumin staining of tPRD were graded on a scale of 0 to 3+ based on the distribution and intensity of staining. Mean (standard deviation) IgG/albumin staining ratios were 0.186 ± 0.239 for MCD, 0.423 ± 0.334 for FSGS-tip (P = 0.0001 versus MCD) and 0.693 ± 0.297 for FSGS-NOS (P < 0.0001 versus MCD; P = 0.0001 versus FSGS-tip). Of 84 biopsies with a ratio ≤0.33, 63 (75%) showed MCD, whereas among 21 with a ratio of 1.0, all but one showed FSGS (15 FSGS-NOS). In summary, IgG/albumin staining in tPRD was correlated with histologic diagnosis in renal biopsies with MCD and FSGS. A ratio of ≤0.33 was associated with MCD, whereas a ratio of 1.0 was most often seen with FSGS-NOS.

Abstract 3817: Systems biology identifies that Gleevec reverses taxane resistance in solid tumors by selective inhibition of a novel +Tip microtubule-binding variant

Abstract The microtubule (MT) cytoskeleton is a validated therapeutic target in oncology, evidenced by the wide use of taxanes in solid tumors including gastric cancer (GC). Post-hoc analysis of the clinical trial that led to docetaxel approval in GC, revealed that patients with diffuse histological subtype were intrinsically resistant to taxane chemotherapy. Using a panel of GC cell lines intrinsically sensitive or resistant to taxanes, we showed lack of drug-target engagement in the resistant lines, despite unimpaired intracellular drug accumulation and absence of tubulin mutations. We discovered a novel, truncated variant of the MT +TIP binding protein CLIP1, hereafter CLIP1S, which was significantly enriched in the resistant cells. Mass-spec proteomics and 5’RACE showed that CLIP1S lacked the first 150 amino acids, thus, missing the Cap-Gly domain required for MT +TIP localization. Confocal microscopy of endogenous or exogenous tagged proteins revealed that CLIP1S was indeed mislocalized from the +TIP to the MT lattice in contrast to +TIP localization of canonical CLIP1. Stable CLIP1S-Knock Down (KD) entirely reversed taxane-resistance (~300 fold), establishing causation between CLIP1S and taxane resistance. Quantitation of drug-binding kinetics using live-cell imaging of Flutax-2 (fluorescently-labeled taxane) in native cytoskeletons, showed that CLIP1S caused Flutax-2 to have significantly reduced affinity and increased dissociation rates from MTs, as compared with cells expressing only the canonical CLIP1. CLIP1S-KD, fully restored Flutax-2 binding, implicating CLIP1S in impeding taxane-MT interaction. Co-administration of chemical probes specific for the low affinity taxane binding site on MT surface further implicated CLIP1S in partially obstructing the MT pore thereby restricting taxane access in the MT lumen where the high affinity taxane binding site is located. Computational analyses of RNA-seq data from untreated or taxane-treated sensitive and resistant GC cells using a novel bayesian drug-target identification algorithm predicted Imatinib (Gleevec™) as a drug that could overcome CLIP1S mediated taxane resistance. Indeed, imatinib completely reversed taxane resistance, phenocopying the sensitization observed with the CLIP1S-KD. Most importantly, we showed that imatinib reversed taxane resistance by specific inhibition of CLIP1S in a dose-dependent manner as early as 3 h post-treatment. Taken together, these data identify an entirely novel mechanism of taxane resistance that involves obstruction of the MT pore in the presence of a previously unknown +TIP variant. Through systems biology we identified imatinib as the first specific CLIP1S inhibitor, thereby repurposing imatinib as a novel therapeutic to overcome clinical taxane resistance in GC and beyond. Citation Format: Prashant V. Thakkar, Katsuhiro Kita, Giuseppe Galletti, Neel S. Madhukar, Kyle Cleveland, Isabel Barasoain, Jose Fernando Diaz, Olivier Elemento, Manish A. Shah, Paraskevi Giannakakou. Systems biology identifies that Gleevec reverses taxane resistance in solid tumors by selective inhibition of a novel +Tip microtubule-binding variant [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3817.

A study on variants of focal segmental glomerulosclerosis and their relationship with various biochemical and demographic parameters in kidney biopsies; a single center study

Introduction: Focal segmental glomerulosclerosis (FSGS) is one of the most common glomerular diseases leading to end-stage renal failure. According to Columbia classification, there are five histologic variants for FSGS. Objectives: There is no study about prevalence and clinic-pathological features of its variants up to now in Iran. Patients and Methods: The study was conducted on renal biopsy reports in a laboratory center between 2011- 2015. Of 1108 patients, 234 had FSGS (either secondary or primary). Using light and immunofluorescence microscopies, the diagnosis and the variants of FSGS were determined (according to Columbia classification). Pathological findings like interstitial fibrosis and glomerular sclerosis, para-clinical findings including serum creatinine and proteinuria, and demographic features including gender and age were also recorded. Results: Among 212 patients with primary form of FSGS, 58% were males with the male-to-female ratio of 1.38: The mean age was 38.5± 18.72 years. Classic variant (not otherwise specified; NOS) was the most prevalent variant, comprising 89.1% of all cases. Tip variant comprised of 32.5%, perihilar in 23.1%, collapsing in 0.9%, while cellular was detected in 0.5% of cases. Mean serum creatinine was 1.41± 0.84 mg/dL. Moreover, mean of proteinuria was 2201.8±1134.49 mg/day. Mean interstitial fibrosis/tubular atrophy in the variants were; NOS in 14.9 ±10.87% of cases, Tip; 7.26±11.55% of cases and in perihilar was 10.79±15.75%. Conclusion: Our study indicates that NOS variant of FSGS is a highly prevalent variant in our patients. Among them, the highest proportion of interstitial fibrosis was seen in this variant.

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

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

The Spectrum of Focal Segmental Glomerulosclerosis from Eastern India: Is It Different?

Focal segmental glomerulosclerosis (FSGS) is a disease that is defined entirely by its histopathological appearance. The recent Columbian classification has grouped this disease into various types based on the light microscopic description. There is a paucity of data describing the distribution of its various subtypes from the Indian subcontinent. This study was undertaken with the aim to throw light on the epidemiology and clinical features of primary FSGS in Eastern India. This retrospective study includes our cohort of biopsy-proven FSGS who presented to us from June 2009 to July 2011 and the analysis of their presenting clinical and histopathological features from our center in East India. Out of 347 patients diagnosed with FSGS in this period, 224 patients were included in the study. A total of 167 cases were of not otherwise specified (NOS) variant (74.5%), 30 tip variant (13.39%), 14 perihilar (6.25%), 8 cellular (3.57%), and 5 to the collapsing variant (2.23%). The maximum proteinuria at presentation was seen with the tip variant (7.98 ± 6.6 g/24 h), and the renal functions were most deranged at presentation with the collapsing variant. These findings were different from those described in other populations including higher prevalence of the tip and the perihilar variant, significant difference in the degree of hypertension, proteinuria, and renal dysfunction among the different variants. The Columbian classification has helped to stratify the outcomes of this glomerular disease with respect to its clinical presentation as well as histopathological features. However, the characteristics of the various variants do show a distinctive pattern in various populations based on ethnicities.

Clinicopathological correlation and treatment response of primary focal segmental glomerulosclerosis in adults and adolescents.

The incidence of focal segmental glomerulosclerosis (FSGS) is approximately 10% in children <6 years, 20% in adolescents, and 20-25% in adults. A retrospective observational study was done to document clinicopathological correlation, treatment response, and risk factors in the progression of chronic kidney disease (CKD) of primary FSGS in adults and adolescents. A total of 170 patients were studied with a mean follow-up of 4.32 ± 1.2 years. FSGS not otherwise specified was the most common subtype (56%) followed by tip variant (24%). About 32% had complete remission (CR) at a mean time of 6.4 months, 23% had partial remission (PR) at a mean time of 5.7 months, and 45% had no response to steroids. Persistent nephrotic proteinuria at 3rd and 6th month and presence of interstitial fibrosis and tubular atrophy >30% in renal biopsy are the independent predictors of poor response to treatment. Presence of anemia, interstitial fibrosis, and tubular atrophy of >30% in renal biopsy and the absence of remission after treatment were the independent predictors of CKD progression. Overall renal survival was 78% at 3 years and 54% at 5 years. Renal survival difference with or without nephrotic proteinuria at onset was 39% and 69% at 5 years. Renal survival was higher in patients with normal renal function (66%) compared with those who had renal failure (42%) at 5 years. Renal survival at 5 years for CR was 69%, PR was 49%, and no remission was 42%.

Tip variant of focal segmental glomerulosclerosis: is it truly a benign variant?

Background: Even though frequently described as a benign entity, the outcomes of the tip variant of focal segmental glomerulosclerosis (FSGS) have proven to be unclear. Methods: This retrospective study includes a cohort of tip variant cases who presented to us from 2009 to 2012 and the analysis of their presenting clinical, histopathological features and treatment outcomes in comparison to the not otherwise specified (NOS) variants from our center in East India. Results: Of the 224 biopsies of primary FSGS, 30 cases were the tip variant (13.39%). The mean age of presentation was around 29 years, with 57% being males. A nephrotic presentation was seen in 87% of cases, with 20% showing a presentation at <18 years of age for the first time. Global sclerosis, interstitial fibrosis, tubular atrophy and arteriolar hyalinosis were seen more commonly in the NOS variant. Twenty five patients of tip variant received steroid therapy and eight received alternative immunosuppression. Around 87% of the tip variant cases achieved some form of remission in proteinuria and 13.3% had a doubling of creatinine at a median follow-up of 2 years in comparison to NOS group in which 80% achieved some form of remission and 20% had a doubling of creatinine. Conclusion: Though the histopathological features and treatment responsiveness of the tip variant appear to be better than the NOS variety, the prognostic outcome does not seem to be as favorable as implicated previously with an important percentage of patients showing progressive worsening of renal function within a relatively short time span (2 years) in our cohort.

Focal and segmental glomerulosclerosis: does prognosis vary with the variants?

Focal and segmental glomerulosclerosis (FSGS) is a clinicopathological entity. The following five FSGS variants: Collapsing, cellular, glomerular tip, peri-hilar and not otherwise specified (NOS) are recognized, which may have prognostic value. The aim of this study was to highlight the clinical course and outcome in the different pathological variants of FSGS and to evaluate the predictive risk factors of end-stage renal disease (ESRD). It was a retrospective analysis of biopsy-proven primary FSGS patients who presented over a period of three years. The data were collected from the clinical and biopsy records of the Nephrology Unit. There were 116 patients with biopsy-proven FSGS. The frequency of occurrence of FSGS among all cases of the nephrotic syndrome seen in our unit was 35.47%. NOS was the most common pathological variant (62.2%), followed by peri-hilar (11.2%), cellular (9.4%) and glomerular tip (7.7%), and the least common variant was collapsing (4.3%). Majority of patients with collapsing, NOS and glomerular tip variants had nephrotic range proteinuria. However, the amount of proteinuria was highest in the glomerular tip and collapsing variants. A higher percentage of patients with the collapsing and cellular variants had renal failure at the time of presentation. A higher rate of tubular and interstitial changes was seen in the collapsing and cellular variants. The collapsing and cellular variants showed lower response rate and higher rates of ESRD, while the glomerular tip lesion had the highest remission rate and the lowest rate of ESRD. Poor prognostic factors for ESRD in FSGS were initial renal insufficiency, severe tubulo-interstitial change, initial nonresponsiveness to steroids and collapsing histopathological variant. Our study suggests that histopathological classification of FSGS is of paramount importance in the management and in predicting the prognosis.

Transcription factors bind negatively selected sites within human mtDNA genes.

Transcription of mitochondrial DNA (mtDNA)-encoded genes is thought to be regulated by a handful of dedicated transcription factors (TFs), suggesting that mtDNA genes are separately regulated from the nucleus. However, several TFs, with known nuclear activities, were found to bind mtDNA and regulate mitochondrial transcription. Additionally, mtDNA transcriptional regulatory elements, which were proved important in vitro, were harbored by a deletion that normally segregated among healthy individuals. Hence, mtDNA transcriptional regulation is more complex than once thought. Here, by analyzing ENCODE chromatin immunoprecipitation sequencing (ChIP-seq) data, we identified strong binding sites of three bona fide nuclear TFs (c-Jun, Jun-D, and CEBPb) within human mtDNA protein-coding genes. We validated the binding of two TFs by ChIP-quantitative polymerase chain reaction (c-Jun and Jun-D) and showed their mitochondrial localization by electron microscopy and subcellular fractionation. As a step toward investigating the functionality of these TF-binding sites (TFBS), we assessed signatures of selection. By analyzing 9,868 human mtDNA sequences encompassing all major global populations, we recorded genetic variants in tips and nodes of mtDNA phylogeny within the TFBS. We next calculated the effects of variants on binding motif prediction scores. Finally, the mtDNA variation pattern in predicted TFBS, occurring within ChIP-seq negative-binding sites, was compared with ChIP-seq positive-TFBS (CPR). Motifs within CPRs of c-Jun, Jun-D, and CEBPb harbored either only tip variants or their nodal variants retained high motif prediction scores. This reflects negative selection within mtDNA CPRs, thus supporting their functionality. Hence, human mtDNA-coding sequences may have dual roles, namely coding for genes yet possibly also possessing regulatory potential.