Glomerular parietal epithelial expression of CD44 in minimal change nephrotic syndrome and primary focal segmental glomerulosclerosis: A clinico-pathological study

Introduction: Minimal change nephrotic syndrome (MCNS) and focal segmental glomerulosclerosis (FSGS) are the two common causes of nephrotic syndrome (NS) in both children and adults with overlapping clinical features, but with distinct prognostic and therapeutic implications. The distinction between these relies entirely on histopathology, which can sometimes be difficult. CD44 is expressed by activated parietal epithelial cells, plays a role in matrix deposition and thus in the pathogenesis of FSGS. Aims: To assess the expression of CD44 in MCNS and FSGS and to evaluate its association with the known clinical and histopathological prognostic factors. Materials and Methods: Thirty cases each of MCNS and FSGS were studied. The clinical, laboratory, histopathological, and CD 44 immunohistochemical data were recorded. The findings were analyzed and correlated. A P value of < 0.05 was considered statistically significant. Results: Statistical association was noted between CD44 positivity and serum creatinine (p = 0.031), estimated glomerular filtration rate (p = 0.040), segmental sclerosis (p < 0.001), tubular atrophy (p = 0.027), interstitial fibrosis (p = 0.027), and histological diagnosis (p < 0.001). The sensitivity, specificity, positive predictive, and negative predictive values were 90%, 76.67%, 79.41% and 88.46%, respectively. Conclusions: CD44 immunostain can effectively distinguish MCNS from FSGS. The congruent results of CD44 positivity with known prognostic factors support the possibility of using the CD44 marker as a predictive tool in selecting high-risk patients and offering appropriate therapeutic measures.

Glomerulopatía colapsante en un paciente con Covid-19. Reporte de caso / Collapsing glomerulonephritis in a COVID-19 patient. Case report

La injuria renal aguda por glomerulopatía colapsante, presenta alta morbimortalidad, incluso con requerimiento de diálisis crónica; la Covid-19 es una de sus causas. Se presenta el caso de un paciente con Covid-19 y glomerulopatía colapsante. Varón de 17 años, sin antecedentes patológicos; con historia de cuatro meses de edema, orina espumosa y disminución del flujo urinario. Al examen: anasarca. Exámenes: creatinina 4,2 mg/dl, albumina 1,9 gr/dl, colesterol y triglicéridos aumentados; orina: proteinuria 6,7 gr/24h, leucocituria y hematuria con urocultivo negativo. Serología para VIH, sífilis y hepatitis negativos. Inmunología para lupus negativa, prueba rápida para la Covid-19 IgG (+). La biopsia renal mostró Glomeruloesclerosis Focal y Segmentaria, variante Colapsante. Recibió corticoides y ciclosporina. La creatinina mejoró, la proteinuria se mantiene >3 gr/24horas.

SUMMARY Acute renal injury due to collapsing glomerulonephritis is associated with high morbidity and mortality, requiring chronic dialysis, COVID-19 is one of its causes. A 17-year-old male patient presented with a four-month history of edema, foamy urine and reduction in the urine flow; anasarca was observed at physical examination. Laboratory values showed creatinine 4,2 mg/dl; albumin 1,9 gr/dl; cholesterol and triglycerides were high; proteinuria 6,7 gr/24h: leucocyturia and hematuria with negative urine culture. Serologies for HIV, syphilis and hepatitis were negative. Studies for systemic lupus were negative. An antigenic test for SARS-CoV-2 was positive as well as an IgG. Renal Biopsy showed Focal and Segmental Glomerulosclerosis, Collapsing variant. He received corticosteroids and cyclosporine. Creatinine improved; proteinuria remained >3 gr/24 hours.

Clinicopathological features analysis of focal segmental glomerulosclerosis after kidney transplantation / 器官移植

Objective To investigate the clinicopathological features of recurrent and de novo focal segmental glomerulosclerosis (FSGS) after kidney transplantation. Methods Thirty-four recipients pathologically diagnosed with FSGS by renal allograft biopsy were enrolled in this clinical trial. According to the detection of primary diseases of renal allografts and circulating permeability factors, 34 recipients were divided into the recurrent FSGS group (n=12) and de novo FSGS group (n=22). The differences of clinical indexes and the degree of pathological injury of renal allografts were compared between two groups. Results There was no significant difference in the mesangial hyperplasia score, glomerulosclerosis rate, renal tubular atrophy score, interstitial fibrosis score and podocyte proliferation rate between two groups (all P > 0.05). In the recurrent FSGS group, segmental glomerulosclerosis rate of the recipients was 0.10 (0.08, 0.27), lower than 0.19 (0.13, 0.33) in the de novo FSGS group (P < 0.05). No significant difference was found in the incidence of antibody-mediated rejection, drug-induced renal tubular injury and BK virus infection between two groups (all P > 0.05). The incidence of T cell-mediated rejection in the recurrent FSGS group was 17%, lower than 55% in the de novo FSGS group (P < 0.05). Immunohistochemical staining showed that the infiltrating inflammatory cells in the renal allografts were mainly T lymphocytes. The positive rates of C4d deposition in peripheral capillaries between the recurrent and de novo FSGS groups were 33% (4/12) and 32% (7/22), with no significant difference (P > 0.05). Immunofluorescence results revealed IgM deposition in the segmental glomerulosclerosis area of renal allografts in most cases. Electron microscopy showed extensive fusion or segmental distribution of podocytes in the glomerulus of renal allografts. Conclusions The degree of renal functional injury and the incidence of T cell-mediated rejection in the recurrent FSGS group are lower than those in the de novo FSGS group. Comprehensive analysis of preoperative and postoperative clinical manifestations, laboratory testing and pathological examination of kidney transplant recipients contribute to early diagnosis and treatment of recurrent and de novo FSGS.

Role of suPAR in the Pathogenesis of Podocyte Injury of Primary Focal Segmental Glomerulosclerosis / 中山大学学报(医学科学版)

ObjectiveThis study aims to investigate the role of suPAR in the pathogenesis of podocyte injury in FSGS. Methods① The sera of primary FSGS patients （17 cases） were collected. Healthy volunteers （10 cases） and patients with other types of primary nephrotic syndrome （10 cases） were set as normal and disease controls. SuPAR levels were detected by ELISA； ② Podocytes were stimulated by suPAR in vitro， and cells were collected to analyze apoptosis by flow cytometry and for RNAseq analysis； ③ Differentially expressed genes （DEGs） were screened from RNAseq data. Both up-regulated and down-regulated genes were analyzed by KEGG and GO enrichment analysis. Heat map was used to show expression of genes related to podocyte focal adhesion， slit diaphragm and actin dynamics and endocytosis. Differentially expressed genes were verified by qPCR. Results① The level of suPAR in FSGS patients was significantly increased， and that in other nephrotic syndrome（NS） patients was also significantly increased； ② suPAR stimulation significantly altered the transcriptome pattern of human podocytes. A total of 272 up-regulated genes and 288 down-regulated genes were screened； ③ KEGG and GO enrichment analysis of up-regulated and down-regulated genes showed that Focal adhesion and DNA replication and DNA repair related pathways were significantly down-regulated； ④ suPAR did not increase podocyte apoptosis. ConclusionThe level of suPAR is significantly increased in patients with primary FSGS. SuPAR may promote podocyte injury by interfering with genomic homeostasis and disrupting focal adhesion， slit diaphragm， actin dynamics and endocytosis-related functional molecules of podocytes.

De Novo Focal Segmental Glomerulosclerosis (FSGS) Post Covid 19 Vaccination: Case Series in A Single Centre in Malaysia

@#Introduction: Mass COVID-19 vaccination has been pivotal in the fight against this pandemic. The occurrence of glomerular disease following COVID-19 vaccinations particularly mRNA vaccine has been reported. The reported cases in the region are limited and number of cases reported are low in contrast to the total number of vaccine doses given worldwide, the healthcare providers should be alerted about such issues to provide swift and proper management. Case Series: Here, we report 3 cases of Focal segmental glomerulosclerosis (FSGS) following COVID-19 vaccination and their outcomes. Two of the patients received BNT162b2 vaccination and one received CoronaVac vaccination. The mean age of the patients was 33+/-7 years old. The mean duration onset of FSGS was 23+/-19 days post vaccinations. Two of the patients (BNT162b2 vaccination and CoronaVac vaccination) achieved complete remission after corticosteroid therapy. This is the first reported case of De Novo FSGS following CoronaVac vaccination in the literature. The third patient, who received BNT162b2 vaccination and presented late (42 days post vaccination) was not in remission despite three months of immunosuppressive treatment. Conclusion: The treating physician needs to be aware of the possibility of the development of FSGS associated with COVID-19 vaccination and how to proceed with vaccination schedule in these populations. Overall, the advantage of COVID-19 vaccination far outweighs the possibility of COVID-19 vaccine-associated glomerular disease.

Long-term prognostic analysis of IgA nephropathy with focal segmental glomerulosclerosis in children / 中华肾脏病杂志

Objective:To analyze the long-term prognosis of IgA nephropathy (IgAN) with focal segmental glomerulosclerosis (FSGS) and the risk factors related to renal prognosis in children with IgAN-FSGS.Methods:A retrospective study was concluded in IgAN-FSGS children who were followed up for more than 5 years and diagnosed by renal biopsy for the first time in the Eastern Theater General Hospital from January, 2004 to December, 2018. The end-point events of the study were entering end-stage kidney disease (ESKD) or estimated glomerular filtration rate (eGFR) decreased by ≥50% from baseline, which were defined as poor renal prognosis. Baseline clinicopathologic data of IgAN-FSGS children were compared between the end-point event group and the non-end-point event group. The cumulative renal survival rate of IgAN-FSGS children was calculated by Kaplan-Meier survival analysis. The influencing factors of poor renal prognosis in IgAN-FSGS children were analyzed by Cox proportional hazards model, and the diagnostic value was evaluated by the receiver operating characteristic curve (ROC curve) and area under the curve (AUC). The diagnostic value was verified by time dependent-ROC and time dependent-AUC.Results:A total of 204 IgAN-FSGS children were enrolled in this study, of whom 132 cases were males (64.7%). The median age of renal biopsy was 16 (14, 17) years old. During a median follow-up time of 90.7 (71.7, 114.8) months, 57 cases (27.9%) reached the end-point events. Compared with the non-end-point event group ( n=147), the end-point event group ( n=57) had higher proportions of males and hypertension, higher levels of 24-hour urinary protein, serum creatinine, serum uric acid, urinary N-acetyl-β- D-glucosaminidase, urinary retinol binding protein, higher proportions of glomerular segmental sclerosis (S1) ≥25% and tubular atrophy/interstitial fibrosis (T1/T2), and lower levels of serum albumin, serum IgA, and serum IgG (all P<0.05). There was no statistical difference between the two groups in treatment (all P>0.05). Kaplan-Meier survival analysis showed that with entry of ESKD or eGFR decreased by ≥50% from baseline as the end-point events, the 5-year, 10-year, and 15-year cumulative renal survival rates in IgAN-FSGS children were 88.7%, 67.6%, and 50.7%, respectively. Multivariate Cox regression analysis showed that proteinuria >1 g/24 h ( HR=3.702, 95% CI 1.657-8.272, P=0.001), hyperuricemia ( HR=3.066, 95% CI 1.793-5.245, P<0.001), S1≥25% ( HR=2.017, 95% CI 1.050-3.874, P=0.035), T1/T2 ( HR=1.863, 95% CI 1.021-3.158, P=0.016) were the independent related factors for poor renal prognosis. ROC curve analysis showed that S1≥25% ( AUC=0.605, P=0.021, sensitivity 26.3%, specificity 94.6%), T1/T2 ( AUC=0.624, P=0.006, sensitivity 43.9%, specificity 81.0%), hyperuricemia ( AUC=0.658, P<0.001, sensitivity 52.6%, specificity 78.9%), proteinuria>1 g/24 h ( AUC=0.670, P<0.001, sensitivity 87.7%, specificity 46.3%) could accurately predict the renal outcome of IgAN-FSGS. Time dependent-ROC curve validation showed that the combined diagnosis of S1≥25%, T1/T2, hyperuricemia and proteinuria>1 g/24 h had a good predictive value for renal prognosis (3-year AUC=0.846 and 5-year AUC=0.777, respectively). Conclusions:During a median follow-up of 90.7 months, 27.9% of IgAN-FSGS children have poor renal prognosis, and the 5-year, 10-year, and 15-year cumulative renal survival rates are 88.7%, 67.6%, and 50.7%, respectively. Urinary protein >1 g/24 h, hyperuricemia, T1/T2, and S1 ≥25% are the risk factors for renal prognosis in IgAN-FSGS children.

Takayasu arteritis associated with focal and segmentary glomerulosclerosis

Takayasu arteritis (TA) is a large vessel vasculitis that affects young people, related to cardiovascular outcomes and chronic kidney disease. We present the case of a 20-year-old male with a diagnosis of TA, who developed chronic kidney disease, impaired renal blood flow was ruled out, renal biopsy was compatible with focal and segmental glomerulosclerosis of a collapsing variety, other possible aetiologies were excluded. The mechanisms that mediate this association have not been determined, immune-mediated mechanisms are proposed. According to our review, this is the second reported case of this association and the first with a collapsing variety.

La arteritis de Takayasu es una vasculitis de grandes vasos que afecta a personas jóvenes y se relaciona con desenlaces cardiovasculares y enfermedad renal crónica. Se presenta el caso de un paciente masculino de 20 arios, con diagnóstico de arteritis de Takayasu, que desarrolla enfermedad renal crónica. Se descartan alteraciones en el flujo sanguíneo renal, en tanto que la biopsia renal resulta compatible con glomeruloesclerosis focal y segmentaria de variedad colapsante. Se excluyeron otras posibles etiologías. No se han determinado los mecanismos que median en esta asociación; se proponen mecanismos inmunomediados. Según nuestra revisión, se trata del segundo caso reportado de esta asociación y el primero con variedad colapsante.

Focal segmental glomerulosclerosis in a patient with congenital lecithin-cholesterol acyltransferase deficiency

Lecithin-cholesterol acyltransferase deficiency is a rare genetic disease caused by a mutation of the gene coding for the lecithin-cholesterol acyltransferase protein, and mainly affects low density lipoprotein metabolism. It typically manifests with diffuse corneal opacities, normocytic anemia and kidney disease. We present the case of a 30-year-old man with chronic kidney disease and nephrotic syndrome. His initial kidney biopsy showed focal segmental glomerulosclerosis, thought to be primary, a disease which was refractory to multiple immunosuppressive schemes. Manifestations such as anemia, splenomegaly, corneal opacities and an association with low high-density lipoproteins alerted to the possibility of glomerular damage secondary to lecithin-cholesterol acyltransferase enzyme deficiency, which was confirmed through genetic sequenc ing. Due to the low incidence of the disease, diagnosis is a clinical challenge. The signs and symptoms tend to be interpreted as isolated events, which significantly delays its confirmation. Understanding this entity and the clinical exercise needed to arrive at its diagnosis will serve as a reference, resulting in the suspicion and reporting of cases in the future. (Acta Med Colomb 2022; 47. DOI:https://doi.org/10.36104/amc.2022.2558).

La deficiencia de lecitin-colesterol aciltransferasa es una enfermedad genética rara, causada por una mutación en el gen que codifica la proteína lecitin-colesterol aciltransferasa y afecta principalmente el metabolismo de las lipoproteínas de baja densidad. Se manifiesta típicamente con opacidades corneales difusas, anemia normocítica y enfermedad renal. Se presenta el caso de un hombre de 30 años con enfermedad renal crónica y síndrome nefrótico, con biopsia renal inicial que demostró un patrón de glomeruloesclerosis focal y segmentaria, interpretada como primaria, enfermedad que fue refractaria a múltiples esquemas de inmunosupresión. Las manifestaciones como anemia, esplenomegalia, opacidades corneales y la asociación con lipoproteínas de alta densidad bajas, alertaron sobre la posibilidad de compromiso glomerular secundario a un déficit de la enzima lecitin-colesterol aciltransferasa, confirmado mediante estudio de secuenciación genética. Dada la baja incidencia de la enfermedad, el diagnóstico representa un desafío clínico. Las manifestaciones suelen interpretarse como eventos aislados, lo que lleva a retraso significativo en su confirmación. El conocimiento de esta entidad y el ejercicio clínico necesario para llegar al diagnóstico, servirán como referencia que derive en la sospecha y reporte de futuros casos. (Acta Med Colomb 2022; 47. DOI:https://doi.org/10.36104/amc.2022.2558).

Clinical and pathological features in children diagnosed with primary focal segmental glomerulosclerosis after repeated renal biopsy / 中华肾脏病杂志

Objective:To analyze the clinical and pathological characteristics in children diagnosed with primary focal segmental glomerulosclerosis (FSGS) after repeated renal biopsy.Methods:The clinicopathological data of children who ever experienced renal biopsy in Jinling Hospital from January 1, 2000 to December 31, 2020 were retrospectively reviewed. Clinical manifestations, pathological characteristics and treatment responses were analyzed.Results:Of the 34 enrolled patients, there were 22 males and 12 females. The median age of the first renal biopsy was 14 years old (1-18 years old), and the median interval between repeat renal biopsy and first renal biopsy was 6 months (1-151 months). Thirty-one showed nephrotic syndrome, of which 22 had microscopic hematuria, and 4 had elevated serum creatinine. Among the other 3 patients, 2 had hematuria and proteinuria, and 1 had proteinuria. In the first renal biopsy, 16 cases were diagnosed as minimal change disease, 14 cases were diagnosed as mesangial proliferative glomerulonephritis, 2 cases were diagnosed as IgA nephropathy, and 2 cases were diagnosed as IgM nephropathy. All 34 children showed poor responses to hormone and immunosuppressive therapies. The pathological features of the first renal biopsy in some patients were adhesion (2/34), decreased loop podocyte attachment (2/34), peripheral loop extension to the urinary pole (2/34), renal tubular reflux (4/34), capillary thrombosis (2/34) and IgM deposition (12/34).Conclusions:The initial diagnosis of FSGS is difficult, and the lesions are atypical and easily misdiagnosed. The patients have poor responses to hormone and immunosuppressive therapies. For patients with the pathological changes of adhesion, decreased loop podocyte attachment, peripheral loop extension to the urinary pole, renal tubular reflux, capillary thrombosis and IgM deposition, follow-up is required, and if necessary, repeat renal biopsy needs be performed to determine whether it is FSGS.

Nefropatía por inmunoglobulina M: características histopatológicas y clínicas. Serie de casos / Immunoglobulin M nephropathy: histopathological and clinical characteristics. Case series

La nefropatía por inmunoglobulina M (NIgM) es una glomerulopatía idiopática caracterizada por depósitos mesangiales globales y difusos de IgM. Se realizó un estudio retrospectivo de las características clínicas e histopatológicas de los pacientes con NIgM atendidos en nuestro servicio. De 241 biopsias renales, 21 correspondieron a NIgM (8,7 %). Se incluyeron 18 pacientes (14 de sexo femenino, mediana de edad: 3,08 años). Se excluyó a 1 paciente por enfermedad sistémica asociada y a 2 por seguimiento menor a 1 año. Catorce pacientes se manifestaron con síndrome nefrótico (SN) y 4 con proteinuria aislada o asociada a hematuria. En la microscopia óptica, 13 presentaron hiperplasia mesangial, y 5 esclerosis focal y segmentaria. De los pacientes con SN, 7 fueron corticorresistentes, 4 corticodependientes y 3 presentaban recaídas frecuentes. Todos los pacientes con SN y 1 con proteinuria-hematuria recibieron inmunosupresores; los 18 pacientes recibieron, además, antiproteinúricos. Luego de 5,2 años (2-17,5) de seguimiento, 6 pacientes evolucionaron a enfermedad renal crónica

Immunoglobulin M nephropathy (IgMN) is an idiopathic glomerulopathy characterized by diffuse global mesangial deposits of IgM. We retrospectively studied the clinical and histopathological characteristics of the patients with IgMN seen in our service. Of 241 renal biopsies, 21 corresponded to IgMN (8.7 %). One patient was excluded due to associated systemic disease and 2 due to follow-up less than 1 year, 18 were included (14 girls, median age 3.08 years). Fourteen manifested with nephrotic syndrome (NS) and the remaining with proteinuria (isolated or associated with hematuria). On light microscopy, 13 had hyperplasia with mesangial expansion and 5 had focal and segmental sclerosis. Of the patients with NS, 7 were steroid-resistant, 4 steroid-dependent, and 3 frequent relapsers. All patients with NS and 1 with proteinuria-hematuria received immunosuppressants; the 18 patients also received antiproteinuric drugs. After 5.2 years (2-17.5) of follow-up, 6 patients developed chronic kidney disease.

Rituximab therapy for adult patients with idiopathic focal segmental glomerulosclerosis / 中华肾脏病杂志

Objective:To evaluate the efficacy and safety of rituximab in the treatment of adult primary focal segmental glomerulosclerosis (FSGS).Methods:Adult FSGS patients treated with rituximab in the First Affiliated Hospital of Zhejiang University College of Medicine were retrospectively enrolled. One or two doses of rituximab (375 mg/m 2) were used aiming to achieve B cell depletion (defined as<5 B cells per microliter in peripheral blood) and the interval between the two doses was 2 weeks. The evaluated major outcomes were remission and relapse of nephropathy, and the secondary outcome measures were adverse events and renal outcomes. Results:A total of 14 patients (9 males) were enrolled, among whom 7 cases were steroid-dependent nephrotic syndrome (SDNS) or frequently relapsing nephrotic syndrome (FRNS), 6 cases were steroid-resistant nephrotic syndrome (SRNS) and one patient was new onset FSGS with contraindication to steroid. After treatment with rituximab, 7 patients with SDNS/FRNS achieved complete remission. At 6 months, the daily oral steroid dose reduced significantly compared with the baseline [(33.3±5.2) mg/d vs (6.7±6.6) mg/d, P<0.01]; while one patient still received tacrolimus 1.0 mg/d, the other 6 patients stopped using immunosuppressants; and the total number of relapse/total follow-up months decreased from 0.257 times/month to 0.058 times/month after the use of rituximab. For the other 6 SRNS patients and one patient with contraindication to steroid, three SRNS patients achieved partial remission and one patient with contraindication to steroid achieved complete remission at 34.50(20.25, 95.25) days after use of rituximab, and the other 3 SRNS patients failed to achieve remission, of whom one patient developed end stage renal disease at 23 months. Conclusions:Rituximab may reduce the risk of relapse and help steroid or immunosuppressant-tapering in adult steroid-dependent/frequently relapsing idiopathic FSGS. However, it is not effective in SRNS patients.

Association of karyomegalic interstitial nephritis with focal segmental glomerulosclerosis

Karyomegalic interstitial nephritis (KIN), first described in 1974, is a rare form of chronic tubulointerstitial nephritis. It is defined by the presence of markedly enlarged, hyperchromatic nuclei with prominent nucleoli, mainly involving tubular epithelial cells of the kidney, accompanied by marked interstitial fibrosis. The disease presents as asymptomatic proteinuria, gradually progresses to chronic kidney disease and eventually leads to end-stage renal disease by 30-40 years. The etiology of the disease remains unclear; however, genetic risk factors and possible association with HLA (B27/35) is proposed by some. It has also been linked to FAN1 (FANCD2/FANC1- associated nuclease 1) mutation. Case Report We present two cases of KIN with associated focal segmental glomerulosclerosis. Both patients presented with nephrotic range proteinuria. The biopsies demonstrated marked enlargement of tubular nuclei (3-5x larger than the uninvolved tubular nuclei, a metric used by some authors in previous studies) in some tubules, meeting the diagnostic criteria of KIN.. Interestingly, case one had a prior biopsy that showed minimal change disease. In the biopsies done at our institution, H&E sections showed patchy tubular attenuation with readily recognizable tubular cell mitotic figures, indicating concurrent acute tubular injury. Electron microscopy showed diffuse podocyte foot process effacement, along with microvillous transformation, podocyte hypertrophy, and cytoplasmic vacuoles, suggesting podocyte injury. This cytoplasmic vacuolization was also observed in the tubular epithelial cells. In both cases, the injury factor appeared to target both podocytes and tubular cells.

Collapsing focal segmental glomerulosclerosis probably triggered by dengue virus infection - two case reports / Glomeruloesclerose Segmentar e Focal Colapsante provavelmente desencadeada por infecção pelo vírus da dengue - dois relatos de caso

Abstract The reported cases describe the association between collapsing focal segmental glomerulosclerosis (FSGS) and acute dengue virus infection. In both cases, patients were diagnosed with dengue virus infection and had a severe kidney disease, with nephrotic syndrome and acute kidney injury. Kidney biopsy was performed and showed collapsing FSGS. The first patient, a 27-year-old man, was diagnosed with dengue virus infection and developed nephrotic syndrome after two weeks of illness. He was treated with methylprednisolone for three days and intravenous furosemide. This patient evolved well, although his renal function did not fully recover. The second patient, a 32-year-old man, was diagnosed with a milder clinical presentation of dengue virus infection. He had a past medical history of nephrotic syndrome in childhood, which might have caused its relapse. This patient was treated with intravenous furosemide and also did not fully recover renal function. These cases highlight the possible implication of dengue virus infection in the etiology of collapsing variant of FSGS. Healthcare professionals should be prepared to identify similar cases.

Resumo Os casos relatados descrevem a associação entre glomeruloesclerose segmentar e focal (GESF) colapsante e infecção aguda pelo vírus da dengue. Nas duas instâncias os pacientes foram diagnosticados com infecção pelo vírus da dengue e apresentaram doença renal grave, com síndrome nefrótica e insuficiência renal aguda. A biópsia renal revelou a presença de GESF colapsante. O primeiro paciente, um homem de 27 anos, foi diagnosticado com infecção pelo vírus da dengue e desenvolveu síndrome nefrótica após duas semanas de doença. Ele foi tratado com metilprednisolona por três dias e furosemida endovenosa. O paciente evoluiu bem, embora sua função renal não tenha se recuperado plenamente. O segundo paciente, um homem de 32 anos, foi diagnosticado com apresentação clínica mais discreta de infecção pelo vírus da dengue. Ele tinha histórico de síndrome nefrótica na infância, o que pode ter causado a recidiva. O paciente foi tratado com furosemida endovenosa e também não recuperou plenamente sua função renal. Os dois casos destacam a possível implicação da infecção pelo vírus da dengue na etiologia da variante colapsante da GESF. Os profissionais de saúde devem estar preparados para identificar casos semelhantes.

Scrub typhus leading to focal segmental glomerulosclerosis in a child due to genetic predisposition

Scrub typhus is a multisystem disease, caused by genera orientia tsutsugamushi and is currently endemic in India. In children, the disease may vary from a mild to a severe form. Complications include encephalitis, myocarditis, disseminated intravascular coagulation, acute kidney injury, atypical pneumonia, etc. The pathophysiologic mechanisms of renal involvement in scrub typhus include prerenal failure, septic shock, vasculitis, acute tubular injury and direct renal invasion by rickettsia. Here, authors present the case of a previously well 5-year old female child who was admitted to our hospital with a history of high-grade fever and pain abdomen. IgM scrub typhus turned out to be positive and she was adequately treated with doxycycline. She turned afebrile but then gradually developed anasarca, hematuria, proteinuria and persistent stage 2 hypertension. Kidney biopsy was done which revealed focal segmental glomerulosclerosis (FSGS). Further workup of the patient by whole exome sequencing revealed missense mutations in TBX18, INF2 and NPHS1 genes. Mutations in INF2 gene is a recently discovered cause of autosomal dominant FSGS. In our case, the scrub typhus mediated kidney injury probably acted as a trigger in unmasking FSGS in the already genetically susceptible child.

Rare inherited kidney diseases: an evolving field in Nephrology / Doenças renais hereditárias raras: um campo em evolução na Nefrologia

Abstract There are more than 150 different rare genetic kidney diseases. They can be classified according to diagnostic findings as (i) disorders of growth and structure, (ii) glomerular diseases, (iii) tubular, and (iv) metabolic diseases. In recent years, there has been a shift of paradigm in this field. Molecular testing has become more accessible, our understanding of the underlying pathophysiologic mechanisms of these diseases has evolved, and new therapeutic strategies have become more available. Therefore, the role of nephrologists has progressively shifted from a mere spectator to an active player, part of a multidisciplinary team in the diagnosis and treatment of these disorders. This article provides an overview of the recent advances in rare hereditary kidney disorders by discussing the genetic aspects, clinical manifestations, diagnostic, and therapeutic approaches of some of these disorders, named familial focal and segmental glomerulosclerosis, tuberous sclerosis complex, Fabry nephropathy, and MYH-9 related disorder.

Resumo As doenças renais genéticas raras compreendem mais de 150 desordens. Elas podem ser classificadas segundo achados diagnósticos como (i) distúrbios do crescimento e estrutura, (ii) doenças glomerulares, (iii) tubulares e (iv) metabólicas. Nos últimos anos, houve uma mudança de paradigma nesse campo. Os testes moleculares tornaram-se mais acessíveis, nossa compreensão sobre os mecanismos fisiopatológicos subjacentes a essas doenças evoluiu e novas estratégias terapêuticas foram propostas. Portanto, o papel do nefrologista mudou progressivamente de mero espectador a participante ativo, parte de uma equipe multidisciplinar, no diagnóstico e tratamento desses distúrbios. O presente artigo oferece um panorama geral dos recentes avanços a respeito dos distúrbios renais hereditários raros, discutindo aspectos genéticos, manifestações clínicas e abordagens diagnósticas e terapêuticas de alguns desses distúrbios, mais especificamente a glomeruloesclerose segmentar e focal familiar, complexo da esclerose tuberosa, nefropatia de Fabry e doença relacionada ao MYH9.

Focal and Segmental Glomerulosclerosis and Membranous Nephropathy overlapping in a patient with Nephrotic Syndrome: a case report / Glomeruloesclerose Segmentar e Focal e Nefropatia Membranosa sobrepostas em paciente com Síndrome Nefrótica: relato de caso

Abstract Introduction: Some cases of membranous nephropathy (MGN) present focal segmental glomerulosclerosis (FSGS) typically associated with disease progression. However, we report a case of a patient who seemed to have MGN and FSGS, both primary. Case presentation: A 17-year-old female, Caucasian, presenting lower extremity edema associated with episodes of foamy urine and high blood pressure, had physical and laboratorial exams indicating nephrotic syndrome. A renal biopsy was performed and focal and segmental glomerulosclerosis were observed under light microscopy in some glomeruli presented as tip lesion, and in others it was accompanied by podocyte hypertrophy and podocyte detachment in urinary space, compatible with podocytopathy FSGS. Besides, there were thickened capillary loops with basement membrane irregularities due to "spikes" compatible with MGN stage II. Immunofluorescence showed finely granular IgG, IgG4, and PLA2R deposits in capillary loops and, in electron microscopy, subepithelial deposits and foot process effacement. These morphological findings are compatible with FSGS and MGN stage II. Conclusions: In the present case, clinical and morphological characteristics showed a possible overlap of primary FSGS and MGN as focal and segmental glomerulosclerosis does not seem to be related with MGN progression but with the podocytopathy FSGS.

Resumo Introdução: Alguns casos de nefropatia membranosa (NM) apresentam glomeruloesclerose segmentar e focal (GESF) tipicamente associada a progressão da doença. Contudo, relatamos o caso de uma paciente que parece ter NM e GESF, ambas primárias. Apresentação do caso: Uma jovem branca de 17 anos de idade com edema de membros inferiores associado a episódios de urina espumosa e hipertensão apresentou-se com achados físicos e laboratoriais sugestivos de síndrome nefrótica. Foi realizada biópsia renal. GESF foi observada por microscopia de luz em alguns glomérulos que apresentavam lesões de ponta, enquanto em outros o achado era acompanhado por hipertrofia podocitária e descolamento de podócitos no espaço urinário, compatíveis com podocitopatia GESF. Além disso, as alças capilares estavam espessadas com irregularidades na membrana basal devido a "espículas" compatíveis com NM estágio II. Imunofluorescência revelou depósitos finamente granulares de IgG, IgG4 e PLA2R nas alças capilares. Microscopia eletrônica exibiu depósitos subepiteliais e apagamento de pedicelos. Tais achados morfológicos são compatíveis com GESF e NM estágio II. Conclusões: No presente caso, as características clínicas e morfológicas revelaram uma possível sobreposição de GESF primária e NM, uma vez que a glomeruloesclerose segmentar e focal não parece estar relacionada com a progressão da NM, mas com a podocitopatia GESF.

Research progress of the mechanism of rituximab in the treatment of focal segmental glomerulosclerosis / 上海交通大学学报（医学版）

Rituximab (RTX), as a monoclonal antibody of CD20 acting on B cell epitopes, has been applied to the field of kidney since 2005, and has become a research hotspot in the clinical treatment of glomerulonephritis. At present, in addition to its clinical safety and efficacy, some researchers are still committed to explore the mechanism of RTX in the treatment of renal diseases, trying to find out whether there is a specific target in renal tissue. In this paper, the mechanism of RTX in the treatment of focal segmental glomerulosclerosis is reviewed.

Unexpectedly High Prevalence of Low Alpha-Galactosidase A Enzyme Activity in Patients with Focal Segmental Glomerulosclerosis

OBJECTIVES: Fabry disease (FD) is a rare disease associated with sphingolipid accumulation. Sphingolipids are components of plasma membranes that are important in podocyte function and accumulate in various glomerular diseases such as focal segmental glomerulosclerosis (FSGS). Both FD and FSGS can cause podocyte damage and are classified as podocytopathies. In this respect, FD and FSGS share the same pathophysiologic pathways. Previous screening studies have shown that a significant proportion of end-stage renal disease (ESRD) patients receiving hemodialysis (HD) have unsuspected FD, and the prevalence of low alpha-galactosidase A (αGLA) enzyme activity in these patients is higher than that in the normal population. We aimed to compare αGLA enzyme activity in patients with biopsy-proven FSGS and ESRD receiving HD. METHODS: The records of 232 patients [62 FSGS (F/M: 33/29); 170 HD (M/F: 93/79)] were evaluated retrospectively. The screening was performed based on the αGLA enzyme activity on a dried blood spot, with the confirmation of plasma LysoGb3 levels, and the known GLA mutations were tested in patients with low enzyme activities. The two groups were compared using these parameters. RESULTS: The mean level of αGLA enzyme activity was found to be lower in FSGS patients than in the HD group (2.88±1.2 μmol/L/h versus 3.79±1.9 μmol/L/h, p<0.001). There was no significant relationship between the two groups with regard to the plasma LysoGb3 levels (2.2±1.22 ng/ml versus 1.7±0.66 ng/ml, p: 0.4). In the analysis of GLA mutations, a D313Y mutation [C(937G>T) in exon p] was found in one patient from the FSGS group. CONCLUSIONS: We found that αGAL activity in patients with FSGS is lower than that in patients undergoing HD. The low enzyme activity in patients with FSGS may be explained by considering the similar pathogenesis of FSGS and FD, which may also lead to sphingolipid deposition and podocyte injury.

Retrospective analysis of clinical data and treatment of primary focal segmental glomerulosclerosis patients / Análisis retrospectivo de datos clínicos y tratamiento de pacientes con glomeruloesclerosis segmentaria focalprimaria

Abstract Introduction: The aim of the study is to compare clinical data of primary focal segmental glomerulosclerosis patients with other data in the literature. In addition, initial immunosuppressive therapy (steroid, calcineurin inhibitors) responses are aimed to be compared with the results in the literature. Methods: Forty seven patients, who were followed up for at least 12 months with primary focal segmental glomerulosclerosis as a result of kidney biopsy. Results of biochemical tests and treatment modalities were evaluated. Results: The mean age of the 47 patients with primary focal segmental glomerulosclerosis was 45.68 (± 13.92). Twenty-one (44.6 %) of 47 patients had anangiotensin converting enzyme inhibitor / angiotensin receptor blocker, 7 (14.8 %) had only corticosteroids, and 6 (12. 7%) had calcineurin inhibitor + low-dose corticosteroids treatment. Thirteen patients (27.6 %) used calcineurin inhibitor + low-dose corticosteroids after receiving corticosteroids treatment. The patients who received corticosteroids or calcineurin inhibitor + low-dose corticosteroids treatment as the initial treatment were compared at the 0, 6 and 12 months of treatment in terms of laboratory and clinical features. At the end of the first year, 4 out of 6 (66 %) patients with low-dose corticosteroids and calcineurin inhibitor and 6 out of (86 %) of 7 patients with corticosteroids had remission (p>0.05). Conclusion: We found the initial steroid treatment and calcineurin inhibitor treatment to be equally effective. We thought that patients with steroid intolerance could be given calcineurin inhibitor in the first step, but if the cost is considered, the first option, such as The Kidney Disease Improving Global Outcomes recommendation, was again steroid.

Resumen Introducción:El objetivo del estudio es comparar los datos clínicos de pacientes con glomeruloesclerosis segmentaria focal primaria con otros datos de la bibliografía. Asimismo, se busca comparar las respuestas de la terapia inmunosupresora inicial (esteroides, inhibidores de la calcineurina) con los resultados en las publicaciones citadas. Material y métodos: Se incluyeron 47 pacientes con glomeruloesclerosis segmentaria focal primaria como resultado de una biopsia renal, y cuyo seguimiento duró, al menos, 12 meses. Se evaluaron los resultados de las pruebas bioquímicas y las modalidades de tratamiento. Resultados: La edad media de los 47 pacientes con glomeruloesclerosis segmentaria focal primaria fue de 45,68 (± 13,92). 21 (44,6 %) del total de los pacientes tenían un inhibidor de la enzima convertidora de la angiotensina / bloqueante del receptor de la angiotensina. Siete pacientes (14,8 %) solo tenían corticosteroides y 6 (12,7 %) tenían un inhibidor de la calcineurina + un tratamiento con esteroides en dosis bajas. Se aplicóinhibidores de la calcineurina + dosis bajas de corticoesteroides en13 pacientes (27,6 %) después de recibir tratamiento con ciclosporina. Los pacientes que recibieron ciclosporina o inhibidores de la calcineurina+ dosis bajas de esteroides como tratamiento inicial se compararon al inicio del tratamiento, a los 6 y 12 meses en sus parámetros de laboratorio y características clínicas. Al final del primer año, 4 de 6 pacientes (66,7 %) con dosis bajas de ciclosporina e inhibidores de la calcineurina y 6 de 7 pacientes (85,7 %) con ciclosporina presentaron remisión (p>0,05). Conclusión: Se encontró que el tratamiento inicial con esteroides y el tratamiento con inhibidores de la calcineurinason igualmente efectivos. Pensamos que, a los pacientes con intolerancia a los esteroides, se les podría administrarinhibidores de la calcineurinaen el primer paso, pero si se considera el costo, la primera opción son nuevamente los esteroides, como lo recomienda el consorcio Kidney Disease Improving Global Outcomes.

The metabolomics signature associated with responsiveness to steroid therapy in focal segmental glomerulosclerosis: a pilot study

Abstract Background Focal segmental glomerulosclerosis (FSGS) is considered one of the most severe glomerular diseases and around 80% of cases are resistant to steroid treatment. Since a large proportion of steroid-resistant (SR) FSGS patients progress to end-stage renal disease, other therapeutic strategies may benefit this population. However, identification of non-invasive biomarkers to predict this high-risk population is needed. Objective We aimed to identify the biomarker candidates to distinguish SR from steroid-sensitive (SS) patients using metabolomics approach and to identify the possible molecular mechanism of resistance. Methods Urine was collected from biopsy-proven FSGS patients eligible for monotherapy with prednisolone. Patients were followed for 6-8 weeks and categorized as SS or SR. Metabolite profile of urine samples was analyzed by one-dimensional 1H-nuclear magnetic resonance (1H-NMR). Predictive biomarker candidates and their diagnostic importance impaired molecular pathways in SR patients, and the common target molecules between biomarker candidates and drug were predicted. Results Homovanillic acid, 4-methylcatechol, and tyrosine were suggested as the significant predictive biomarker candidates, while L-3,4-dihydroxyphenylalanine, norepinephrine, and gentisic acid had high accuracy as well. Tyrosine metabolism was the most important pathway that is perturbed in SR patients. Common targets of the action of biomarker candidates and prednisolone were molecules that contributed in apoptosis. Conclusion Urine metabolites including homovanillic acid, 4-methylcatechol, and tyrosine may serve as potential non-invasive predictive biomarkers for evaluating the responsiveness of FSGS patients.