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BackgroundPrimary FSGS manifests with nephrotic syndrome and may recur following KT. Failure to respond to conventional therapy after recurrence results in poor outcomes. Evaluation of podocyte B7-1 expression and treatment with abatacept (a B7-1 antagonist) has shown promise but remains controversial.MethodsFrom 2012 to 2020, twelve patients developed post-KT FSGS with nephrotic range proteinuria, failed conventional therapy, and were treated with abatacept. Nine/twelve (< 21 years old) experienced recurrent FSGS; three adults developed de novo FSGS, occurring from immediately, up to 8 years after KT. KT biopsies were stained for B7-1.ResultsNine KTRs (75%) responded to abatacept. Seven of nine KTRs were B7-1 positive and responded with improvement/resolution of proteinuria. Two patients with rFSGS without biopsies resolved proteinuria after abatacept. Pre-treatment UPCR was 27.0 ± 20.4 (median 13, range 8-56); follow-up UPCR was 0.8 ± 1.3 (median 0.2, range 0.07-3.9, p < 0.004). Two patients who were B7-1 negative on multiple KT biopsies did not respond to abatacept and lost graft function. One patient developed proteinuria while receiving belatacept, stained B7-1 positive, but did not respond to abatacept.ConclusionsPodocyte B7-1 staining in biopsies of KTRs with post-transplant FSGS identifies a subset of patients who may benefit from abatacept. A higher resolution version of the Graphical abstract is available as Supplementary information.

BackgroundFocal segmental glomerulosclerosis (FSGS) is frequently associated with heavy proteinuria and progressive renal failure requiring dialysis or kidney transplantation. However, primary FSGS also has a ~40% risk of recurrence of disease in the transplanted kidney (rFSGS). Multiple circulating factors have been identified to contribute to the pathogenesis of primary and rFSGS including soluble urokinase-type plasminogen activator receptor (suPAR) and patient-derived CD40 autoantibody (CD40autoAb). However, the downstream effector pathways specific to individual factors require further study. The tumor necrosis factor, TNF pathway activation by one or more circulating factors present in the sera of patients with FSGS has been supported by multiple studies.MethodsA human in vitro model was used to study podocyte injury measured as the loss of actin stress fibers. Anti-CD40 autoantibody was isolated from FSGS patients (recurrent and non-recurrent) and control patients with ESRD due to non-FSGS related causes. Two novel human antibodies-anti-uPAR (2G10) and anti-CD40 antibody (Bristol Meyer Squibb, 986090) were tested for their ability to rescue podocyte injury. Podocytes treated with patient derived antibody were transcriptionally profiled using whole human genome microarray.ResultsHere we show that podocyte injury caused by sera from FSGS patients is mediated by CD40 and suPAR and can be blocked by human anti-uPAR and anti-CD40 antibodies. Transcriptomic studies to compare the molecules and pathways activated in response to CD40 autoantibody from rFSGS patients (rFSGS/CD40autoAb) and suPAR, identified unique inflammatory pathways associated with FSGS injury.ConclusionsWe identified several novel and previously described genes associated with FSGS progression. Targeted blockade of suPAR and CD40 pathways with novel human antibodies showed inhibition of podocyte injury in FSGS.

Background Despite renin-angiotensin-aldosterone system blockade and immunosuppressive treatment, focal segmental glomerulosclerosis (FSGS) often progresses to kidney failure. The objective of this prespecified analysis of the dapagliflozin and prevention of adverse outcomes in chronic kidney disease trial (DAPA-CKD) was to assess efficacy and safety of dapagliflozin in a small subgroup of participants with FSGS confirmed by kidney biopsy. Methods In DAPA-CKD, patients with an estimated glomerular filtration rate (eGFR) 25-75 mL/min/1.73 m(2) and urinary albumin:creatinine ratio (UACR) 200-5000 mg/g (22.6-565 mg/mol) were randomized to dapagliflozin 10 mg once daily or placebo as an adjunct to standard care and followed for median 2.4 years. The primary composite endpoint was sustained eGFR decline >= 50%, end-stage kidney disease, or kidney or cardiovascular death. The endpoint of interest for this analysis was eGFR slope (acute effects from baseline to Week 2 and chronic effects from Week 2 to end of treatment). Results Of 104 participants with biopsy-confirmed FSGS, 45 were randomized to dapagliflozin and 59 to placebo. Mean (standard deviation) age was 54.0 (14.3) years, mean eGFR 41.9 (11.5) mL/min/1.73 m(2) and median (interquartile range) UACR 1248 (749-2211) mg/g. The primary outcome occurred in 4 (8.9%) and 7 (11.9%) participants randomized to dapagliflozin and placebo, respectively [hazard ratio 0.62, 95% confidence interval (95% CI) 0.17, 2.17]. Dapagliflozin led to a larger acute reduction (standard error) in eGFR compared with placebo (-4.5, 95% CI -5.9 to -3.1 versus -0.9, -2.1 to 0.4 mL/min/1.73 m(2)/2 weeks). Thereafter, mean rates of chronic eGFR decline with dapagliflozin and placebo were -1.9 (-3.0, -0.9) and -4.0 (-4.9, -3.0) mL/min/1.73 m(2)/year, respectively (difference 2.0, 95% CI 0.6 to 3.5, mL/min/1.73 m(2)/year). Adverse events leading to study drug discontinuation were similar in both groups; there were fewer serious adverse events

Background Despite renin-angiotensin-aldosterone system blockade and immunosuppressive treatment, focal segmental glomerulosclerosis (FSGS) often progresses to kidney failure. The objective of this prespecified analysis of the dapagliflozin and prevention of adverse outcomes in chronic kidney disease trial (DAPA-CKD) was to assess efficacy and safety of dapagliflozin in a small subgroup of participants with FSGS confirmed by kidney biopsy. Methods In DAPA-CKD, patients with an estimated glomerular filtration rate (eGFR) 25-75 mL/min/1.73 m(2) and urinary albumin:creatinine ratio (UACR) 200-5000 mg/g (22.6-565 mg/mol) were randomized to dapagliflozin 10 mg once daily or placebo as an adjunct to standard care and followed for median 2.4 years. The primary composite endpoint was sustained eGFR decline >= 50%, end-stage kidney disease, or kidney or cardiovascular death. The endpoint of interest for this analysis was eGFR slope (acute effects from baseline to Week 2 and chronic effects from Week 2 to end of treatment). Results Of 104 participants with biopsy-confirmed FSGS, 45 were randomized to dapagliflozin and 59 to placebo. Mean (standard deviation) age was 54.0 (14.3) years, mean eGFR 41.9 (11.5) mL/min/1.73 m(2) and median (interquartile range) UACR 1248 (749-2211) mg/g. The primary outcome occurred in 4 (8.9%) and 7 (11.9%) participants randomized to dapagliflozin and placebo, respectively [hazard ratio 0.62, 95% confidence interval (95% CI) 0.17, 2.17]. Dapagliflozin led to a larger acute reduction (standard error) in eGFR compared with placebo (-4.5, 95% CI -5.9 to -3.1 versus -0.9, -2.1 to 0.4 mL/min/1.73 m(2)/2 weeks). Thereafter, mean rates of chronic eGFR decline with dapagliflozin and placebo were -1.9 (-3.0, -0.9) and -4.0 (-4.9, -3.0) mL/min/1.73 m(2)/year, respectively (difference 2.0, 95% CI 0.6 to 3.5, mL/min/1.73 m(2)/year). Adverse events leading to study drug discontinuation were similar in both groups; there were fewer serious adverse events

IntroductionInformation on the economic burden of focal segmental glomerulosclerosis (FSGS) is sparse. This study characterized health care resource utilization (HCRU) and costs in patients with FSGS, and evaluated the impact of nephrotic range proteinuria on these outcomes.MethodsThis retrospective, observational cohort study used administrative claims data from the Optum Clinformatics Data Mart Database from October 2015 to December 2019. Patients with FSGS (n = 844; first claim = index event) between April 2016 and December 2018 were matched on index date, age, sex, and race to non-FSGS controls (n = 1688). FSGS nephrotic range (urine protein/creatinine ratio >3000 mg/g or albumin/creatinine ratio >2000 mg/g) and non-nephrotic subpopulations were identified. Baseline comorbidities, 12-month post-index all-cause HCRU and costs (per patient per year [PPPY]), and immunosuppressant prescriptions were compared between matched cohorts and between FSGS subpopulations.ResultsComorbidity burden was higher in FSGS. Of 308 patients with available urine protein/creatinine ratio/albumin/creatinine ratio results, 36.4% were in nephrotic range. All-cause HCRU was higher in FSGS across resource categories (all P < 0.0001); 50.6% of FSGS and 23.3% of controls were prescribed glucocorticoids (P < 0.0001). Mean total medical costs were higher in FSGS ($59,753 vs. $8431 PPPY; P < 0.0001), driven by outpatient costs. Nephrotic range proteinuria was associated with higher all-cause inpatient, outpatient, and prescription costs versus nonnephrotic patients (all P < 0.0001), resulting in higher total costs ($70,481 vs. $36,099 PPPY; P < 0.0001).ConclusionsFSGS is associated with significant clinical and economic burdens; the presence of nephrotic range proteinuria increased the economic burden. New treatment modalities are needed to reduce proteinuria, help improve patient outcomes, and reduce HCRU and associated costs.

In recent years, many light-microscopy protocols have been published for visualization of nanoscale structures in the kidney. These protocols present researchers with new tools to evaluate both foot process anatomy and effacement, as well as protein distributions in foot processes, the slit diaphragm and in the glomerular basement membrane. However, these protocols either involve the application of different complicated super resolution microscopes or lengthy sample preparation protocols. Here, we present a fast and simple, five-hour long procedure for three-dimensional visualization of kidney morphology on all length scales. The protocol combines optical clearing and tissue expansion concepts to produce a mild swelling, sufficient for resolving nanoscale structures using a conventional confocal microscope. We show that the protocol can be applied to visualize a wide variety of pathologic features in both mouse and human kidneys. Thus, our fast and simple protocol can be beneficial for conventional microscopic evaluation of kidney tissue integrity both in research and possibly in future clinical routines., QC 20211215

A major complication of primary focal segmental glomerulosclerosis (FSGS) is its recurrence after kidney transplantation that happens in 30 to 40% of the patients. The diagnosis of these relapses is not always easy as the histological lesions are not highly specific and appear after the proteinuria increase. Currently, there are no accurate biomarkers to detect FSGS recurrence. Our group identified a modified form of Apolipoprotein A-I (ApoA-I), named ApoA-Ib, specifically present in the urine of recurrent FSGS patients after kidney transplantation. Aberrant forms of ApoA-I have also been described in the urine of native primary FSGS patients; this feature has been associated with prominent staining of ApoA-I at the apical membrane of the tubular cells. In this study, we aim to analyze the ApoA-I distribution in kidney allograft biopsies of recurrent FSGS patients. We detected ApoA-I by immunohistochemistry in kidney allograft biopsies of patients with FSGS relapse after kidney transplantation and in kidney allograft biopsies of patients with a disease different from FSGS in the native kidney (non-FSGS). In recurrent FSGS patients, ApoA-I was prominently localized at the brush border of the tubular cells, while in the non-FSGS patients, ApoA-I was found along the cytoplasm of the tubular cells. The localization of ApoA-I at the brush border of the tubular cells is a specific feature of primary FSGS in relapse. This suggests that ApoA-I staining in kidney biopsies, coupled with ApoA-Ib measurement in urine, could be used as a diagnostic tool of primary FSGS relapse after kidney transplantation due to its highly specific tubular distribution

IntroductionInformation on the economic burden of focal segmental glomerulosclerosis (FSGS) is sparse. This study characterized health care resource utilization (HCRU) and costs in patients with FSGS, and evaluated the impact of nephrotic range proteinuria on these outcomes.MethodsThis retrospective, observational cohort study used administrative claims data from the Optum Clinformatics Data Mart Database from October 2015 to December 2019. Patients with FSGS (n = 844; first claim = index event) between April 2016 and December 2018 were matched on index date, age, sex, and race to non-FSGS controls (n = 1688). FSGS nephrotic range (urine protein/creatinine ratio >3000 mg/g or albumin/creatinine ratio >2000 mg/g) and non-nephrotic subpopulations were identified. Baseline comorbidities, 12-month post-index all-cause HCRU and costs (per patient per year [PPPY]), and immunosuppressant prescriptions were compared between matched cohorts and between FSGS subpopulations.ResultsComorbidity burden was higher in FSGS. Of 308 patients with available urine protein/creatinine ratio/albumin/creatinine ratio results, 36.4% were in nephrotic range. All-cause HCRU was higher in FSGS across resource categories (all P < 0.0001); 50.6% of FSGS and 23.3% of controls were prescribed glucocorticoids (P < 0.0001). Mean total medical costs were higher in FSGS ($59,753 vs. $8431 PPPY; P < 0.0001), driven by outpatient costs. Nephrotic range proteinuria was associated with higher all-cause inpatient, outpatient, and prescription costs versus nonnephrotic patients (all P < 0.0001), resulting in higher total costs ($70,481 vs. $36,099 PPPY; P < 0.0001).ConclusionsFSGS is associated with significant clinical and economic burdens; the presence of nephrotic range proteinuria increased the economic burden. New treatment modalities are needed to reduce proteinuria, help improve patient outcomes, and reduce HCRU and associated costs.

Nephrotic syndrome represents the clinical situation characterized by presence of massive proteinuria and low serum protein caused by a variety of diseases, including minimal change nephrotic syndrome (MCNS), focal segmental glomerulosclerosis (FSGS) and membranous glomerulonephropathy. Differentiating between diagnoses requires invasive renal biopsies in general. Even with the biopsy, we encounter difficulties to differentiate MCNS and FSGS in some cases. There is no other better option currently available for the diagnosis other than renal biopsy. MicroRNAs (miRNAs) are no-coding RNAs of approximately 20 nucleotides in length, which regulate target genes in the post-transcriptional processes and have essential roles in many diseases. MiRNAs in serum and urine have been shown as non-invasive biomarkers in multiple diseases, including renal diseases. In this article, we summarize the current knowledge of miRNAs as the promising biomarkers for nephrotic syndrome.

BackgroundObservational studies show that African American (AA) dialysis patients have longer survival than European Americans. We hypothesized that apolipoprotein L1 (APOL1) genetic variation, associated with nephropathy in AAs, contributes to the survival advantage in AA dialysis patients.MethodsWe examined the association between race and mortality among 37,097 adult dialysis patients, including 54% AAs and 46% European Americans from a large dialysis organization (entry period from July 2001 to June 2006, follow-up through June 2007), within each cause of end-stage renal disease (ESRD) category associated with APOL1 renal risk variants using Cox proportional hazard models.ResultsAA dialysis patients had numerically lower mortality than their European American counterparts for all causes of ESRD. The mortality reduction among AAs compared to European Americans was statistically significant in patients with ESRD attributed to diabetes mellitus, hypertension, and APOL1-enriched glomerulonephritis (GN) (HR [95% CI]: 0.69 [0.66-0.72], 0.73 [0.68-0.79], and 0.89 [0.79-0.99], respectively); these are conditions in which APOL1 variants promote kidney disease. By contrast, the significant survival advantage of AA dialysis patients was not observed in patients with ESRD attributed to other kidney disease (including polycystic kidney disease, interstitial nephritis, and pyelonephritis) and other GN, which are not associated with APOL1 variants.ConclusionsThese data suggest the hypothesis that the relative survival advantage of AA dialysis patients may be related to APOL1 variation. Further large population-based genetic studies are required to test this hypothesis.

Because of its rarity, renal presentation and outcomes of idiopathic nephrotic syndrome (INS; minimal changes disease or focal and segmental glomerulosclerosis) has poorly been described in elderly patients, precluding an individualized therapy procedure. Whether immunosuppressive regimens formerly designed in children and young adults are safe and efficient in elderly remains elusive. In a large multicentric retrospective study that included 116 patients with INS and onset ≥ 60 years of age, we showed that cumulative incidence of renal response was 95% after frontline therapy, with an age-dependent median time-to-response (60 days before 70 years of age at the onset vs. 120 days after; p = 0.03). Cumulative incidence of relapse was 90% at 7 years, with relapse occurring continuously over time. After a median follow-up of 34 months (IQR (12; 57)), 7 patients had died (6%) and 5 reached end-stage renal disease. Complications were highly prevalent: diabetes mellitus (23.3%), hypertension (24.1%), infection requiring hospitalization (21.6%) and acute kidney injury (9.5%). Thus, in older patients with INS and receiving steroids, renal response is delayed and relapse is the rule. Alternative immunosuppressive regimens, including B-cells depleting agents as frontline therapy, should be tested in this subset of patients to improve the mid- to long-term outcomes.

BackgroundObservational studies show that African American (AA) dialysis patients have longer survival than European Americans. We hypothesized that apolipoprotein L1 (APOL1) genetic variation, associated with nephropathy in AAs, contributes to the survival advantage in AA dialysis patients.MethodsWe examined the association between race and mortality among 37,097 adult dialysis patients, including 54% AAs and 46% European Americans from a large dialysis organization (entry period from July 2001 to June 2006, follow-up through June 2007), within each cause of end-stage renal disease (ESRD) category associated with APOL1 renal risk variants using Cox proportional hazard models.ResultsAA dialysis patients had numerically lower mortality than their European American counterparts for all causes of ESRD. The mortality reduction among AAs compared to European Americans was statistically significant in patients with ESRD attributed to diabetes mellitus, hypertension, and APOL1-enriched glomerulonephritis (GN) (HR [95% CI]: 0.69 [0.66-0.72], 0.73 [0.68-0.79], and 0.89 [0.79-0.99], respectively); these are conditions in which APOL1 variants promote kidney disease. By contrast, the significant survival advantage of AA dialysis patients was not observed in patients with ESRD attributed to other kidney disease (including polycystic kidney disease, interstitial nephritis, and pyelonephritis) and other GN, which are not associated with APOL1 variants.ConclusionsThese data suggest the hypothesis that the relative survival advantage of AA dialysis patients may be related to APOL1 variation. Further large population-based genetic studies are required to test this hypothesis.

Alport syndrome, also known as hereditary nephritis, is an inherited progressive form of glomerular disease that is often associated with sensorineural hearing loss and ocular abnormalities. It is caused by mutations in genes encoding several members of type IV colagen proteins primarily found in basement membranes. Genetic analyses of affected families have identified four different modes of transmission in patients with Alport syndrome. X-linked form of the syndrome arises from mutations of COL4A5 and COL4A6 on chromosome X, whereas autosomal forms result from genetic defects in either the COL4A3 or COL4A4 genes at chromosome 2q35-37. Digenic forms include patients with coexisting mutations in COL4A3, COL4A4, and COL4A5., El síndrome de Alport (SA), también conocido como nefritis hereditaria, es una forma progresiva hereditaria de enfermedad glomerular que a menudo se asocia con pérdida auditiva neurosensorial y anomalías oculares. Es causada por mutaciones en los genes que codifican varios miembros de las proteínas de colágeno del tipo IV, que se hallan en las membranas basales principalmente. Los análisis genéticos de las familias afectadas han identificado cuatro modos diferentes de transmisión en pacientes con síndrome de Alport. La forma del síndrome ligada al X surge a partir de mutaciones de COL4A5 y COL4A6 en el cromosoma X, mientras que las formas autosómicas resultan de defectos genéticos tanto en el gen COL4A3 como en el COL4A4, en el cromosoma 2q35-37. Las formas digénicas incluyen pacientes con mutaciones coexistentes en COL4A3, COL4A4 y COL4A5.El resultado clínico a largo plazo en pacientes con SA con mutaciones heterocigotas de COL4A3/A4es generalmente impredecible.La gloméruloesclerosis focal y segmentaria suele desarrollarse en el SA clásico en etapas posteriores y se presenta predominantemente con proteinuria asociada con hematuria. En el caso índice presentado en este informe, a un hombre de 26 años se le realizó una biopsia de riñón debido a una proteinuria nefrótica y una hematuria microscópica acompañada de una función renal alterada. Se le diagnosticó gloméruloesclerosis focal y segmentaria. Debido a que tenía una pérdida auditiva progresiva desde el inicio del estudio, se le realizó un estudio genético de mutaciones en los genes COL4A3 y COL4A4. Se detectó una nueva mutación en el gen COL4A4 (c.1804-7T> C).Debido a que sus padres tenían un matrimonio consanguíneo, el resto de la familia fue sometida a estudio para la misma variante. Sus padres y su hermana fueron heterocigotos y homocigota para la misma variante, respectivamente. En este estudio, se demostró la existencia de una familia con síndrome de Alport con una nueva mutación en el gen COL4A4 (c.1856G> A

Dosadašnja istraživanja pokazala su da renin angiotenzin sistem (RAS) ima važnu ulogu u patogenezi i progresiji fokalno segmentne glomeruloskleroze (FSGS). Oksidativni stres je prisutan u hroničnoj bubrežnoj slabosti i doprinosi progresiji bolesti. Povezanost oksidativnog stresa i RAS u procesima progresije FSGS još je nedovoljno razjašnjena. Stoga su istraživanja u okviru ove disertacije bila usmerena ka ispitivanju efekata hronične primene tempola (sakupljač slobodnih radikala, SOD mimetik), losartana (blokator receptora za angiotenzin II tipa 1, AT1R), kao i njihove kombinacije, na usporavanje progresije FSGS izazvane adrijamicinom (ADR) kod spontano hipertenzivnih (SH) pacova. Životinje su inicijalno deljene u dve eksperimentalne grupe, kontrolnu (SHC) i grupu koja je primila ADR 2 mg/kg i.v. dva puta u intervalu od 21 dan. Nakon druge injekcije ADR, životinje su dobijale vodu (SHADR), losartan (SHADR+L), tempol (SHADR+T) i kombinovani tretman (SHADR+T+L) gavažom. Na kraju šeste nedelje tretmana vršena su hemodinamska merenja i uzorkovanje krvi, urina i bubrega. Na osnovu biohemijskih parametara vršena je procena lipidnog statusa i bubrežne funkcije. Urađena je histopatološka analiza bubrega. Imunihistohemijskom metodom ispitivani su proteini citosketeta, nestin i vimentin, čije izmenjene ekspresije su pokazatelj oštećenja bubrežnog tkiva. Matriksna metaloproteinaza-1 (MMP-1), koja učestvuje u degradaciji komponenti vanćelijskog mariksa i očuvanju integriteta glomerula, određivana je ELISA metodom. Ispitivani su parametri oksidativnog stresa: lipidna peroksidacija i nivo karbonilovanih proteina (PCOs); aktivnosti enzima antioksidativnog sistema: superoksid dismutaze (SOD), katalaze (CAT), glutation peroksidaze (GPx) i glutation reduktaze (GR); kao i antioksidativni kapacitet. Primenom imunohistohemijske, Western blot i ELISA metode u bubrezima su određivane ekspresije Nox2 i Nox4 izoforme katalitičke subjedinice NADPH oksidaze, glavni izvor reaktivnih kiseonični, Previous studies have shown that renin angiotensin system (RAS) plays an important role in the pathogenesis and progression of focal segmental glomerulosclerosis (FSGS). Oxidative stress is involved in the development and progression of chronic kidney disease. However, the association of oxidative stress and RAS in the progression of FSGS has not been completely elucidated. In this study we investigated the effects of chronic tempol (free radical scavenger, SOD mimetic), losartan (selective angiotensin II type 1 receptor (AT1R) blocker), and their combined treatment in slowing down the progression of FSGS, in spontaneously hypertensive (SH) rats with adriamycin (ADR) nephropathy. Animals were initially divided into two experimental groups: control (SHC) and group that received ADR 2 mg/kg i.v. twice in an interval of 21 days. After the second injection of ADR, the animals were given tap water (SHADR), losartan (SHADR+L), tempol (SHADR+T) or combined treatment (SHADR+T+L) by gavage. Hemodynamic measurements were performed, blood, urine, and kidney samples were taken for biochemical and histopathological analysis. Immunohistochemical method was used for protein expression and localization of the nestin and vimentin, proteins of cytoskeleton network, and change in their protein expression is a marker of cell injury. Matrix metalloproteinase-1 (MMP-1), which participates in the degradation of the extracellular matrix components and preserving the integrity of the glomerulus, was determined by the ELISA method. The parameters of oxidative stress: lipid peroxidation, protein carbonyl content (PCOs); antioxidant defense: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and antioxidant capacity were analysed. Immunohistochemical, Western blot and ELISA method were used for analysis of the Nox2 and Nox4 protein expression, isoforms of the catalytic subunit of NADPH oxidase, the main source of reactive oxygen species in the

Previous studies have shown that renin angiotensin system (RAS) plays an important role in the pathogenesis and progression of focal segmental glomerulosclerosis (FSGS). Oxidative stress is involved in the development and progression of chronic kidney disease. However, the association of oxidative stress and RAS in the progression of FSGS has not been completely elucidated. In this study we investigated the effects of chronic tempol (free radical scavenger, SOD mimetic), losartan (selective angiotensin II type 1 receptor (AT1R) blocker), and their combined treatment in slowing down the progression of FSGS, in spontaneously hypertensive (SH) rats with adriamycin (ADR) nephropathy. Animals were initially divided into two experimental groups: control (SHC) and group that received ADR 2 mg/kg i.v. twice in an interval of 21 days. After the second injection of ADR, the animals were given tap water (SHADR), losartan (SHADR+L), tempol (SHADR+T) or combined treatment (SHADR+T+L) by gavage. Hemodynamic measurements were performed, blood, urine, and kidney samples were taken for biochemical and histopathological analysis. Immunohistochemical method was used for protein expression and localization of the nestin and vimentin, proteins of cytoskeleton network, and change in their protein expression is a marker of cell injury. Matrix metalloproteinase-1 (MMP-1), which participates in the degradation of the extracellular matrix components and preserving the integrity of the glomerulus, was determined by the ELISA method. The parameters of oxidative stress: lipid peroxidation, protein carbonyl content (PCOs); antioxidant defense: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and antioxidant capacity were analysed. Immunohistochemical, Western blot and ELISA method were used for analysis of the Nox2 and Nox4 protein expression, isoforms of the catalytic subunit of NADPH oxidase, the main source of reactive oxygen species in the, Dosadašnja istraživanja pokazala su da renin angiotenzin sistem (RAS) ima važnu ulogu u patogenezi i progresiji fokalno segmentne glomeruloskleroze (FSGS). Oksidativni stres je prisutan u hroničnoj bubrežnoj slabosti i doprinosi progresiji bolesti. Povezanost oksidativnog stresa i RAS u procesima progresije FSGS još je nedovoljno razjašnjena. Stoga su istraživanja u okviru ove disertacije bila usmerena ka ispitivanju efekata hronične primene tempola (sakupljač slobodnih radikala, SOD mimetik), losartana (blokator receptora za angiotenzin II tipa 1, AT1R), kao i njihove kombinacije, na usporavanje progresije FSGS izazvane adrijamicinom (ADR) kod spontano hipertenzivnih (SH) pacova. Životinje su inicijalno deljene u dve eksperimentalne grupe, kontrolnu (SHC) i grupu koja je primila ADR 2 mg/kg i.v. dva puta u intervalu od 21 dan. Nakon druge injekcije ADR, životinje su dobijale vodu (SHADR), losartan (SHADR+L), tempol (SHADR+T) i kombinovani tretman (SHADR+T+L) gavažom. Na kraju šeste nedelje tretmana vršena su hemodinamska merenja i uzorkovanje krvi, urina i bubrega. Na osnovu biohemijskih parametara vršena je procena lipidnog statusa i bubrežne funkcije. Urađena je histopatološka analiza bubrega. Imunihistohemijskom metodom ispitivani su proteini citosketeta, nestin i vimentin, čije izmenjene ekspresije su pokazatelj oštećenja bubrežnog tkiva. Matriksna metaloproteinaza-1 (MMP-1), koja učestvuje u degradaciji komponenti vanćelijskog mariksa i očuvanju integriteta glomerula, određivana je ELISA metodom. Ispitivani su parametri oksidativnog stresa: lipidna peroksidacija i nivo karbonilovanih proteina (PCOs); aktivnosti enzima antioksidativnog sistema: superoksid dismutaze (SOD), katalaze (CAT), glutation peroksidaze (GPx) i glutation reduktaze (GR); kao i antioksidativni kapacitet. Primenom imunohistohemijske, Western blot i ELISA metode u bubrezima su određivane ekspresije Nox2 i Nox4 izoforme katalitičke subjedinice NADPH oksidaze, glavni izvor reaktivnih kiseonični

Previous studies have shown that renin angiotensin system (RAS) plays an important role in the pathogenesis and progression of focal segmental glomerulosclerosis (FSGS). Oxidative stress is involved in the development and progression of chronic kidney disease. However, the association of oxidative stress and RAS in the progression of FSGS has not been completely elucidated. In this study we investigated the effects of chronic tempol (free radical scavenger, SOD mimetic), losartan (selective angiotensin II type 1 receptor (AT1R) blocker), and their combined treatment in slowing down the progression of FSGS, in spontaneously hypertensive (SH) rats with adriamycin (ADR) nephropathy. Animals were initially divided into two experimental groups: control (SHC) and group that received ADR 2 mg/kg i.v. twice in an interval of 21 days. After the second injection of ADR, the animals were given tap water (SHADR), losartan (SHADR+L), tempol (SHADR+T) or combined treatment (SHADR+T+L) by gavage. Hemodynamic measurements were performed, blood, urine, and kidney samples were taken for biochemical and histopathological analysis. Immunohistochemical method was used for protein expression and localization of the nestin and vimentin, proteins of cytoskeleton network, and change in their protein expression is a marker of cell injury. Matrix metalloproteinase-1 (MMP-1), which participates in the degradation of the extracellular matrix components and preserving the integrity of the glomerulus, was determined by the ELISA method. The parameters of oxidative stress: lipid peroxidation, protein carbonyl content (PCOs); antioxidant defense: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and antioxidant capacity were analysed. Immunohistochemical, Western blot and ELISA method were used for analysis of the Nox2 and Nox4 protein expression, isoforms of the catalytic subunit of NADPH oxidase, the main source of reactive oxygen species in the, Dosadašnja istraživanja pokazala su da renin angiotenzin sistem (RAS) ima važnu ulogu u patogenezi i progresiji fokalno segmentne glomeruloskleroze (FSGS). Oksidativni stres je prisutan u hroničnoj bubrežnoj slabosti i doprinosi progresiji bolesti. Povezanost oksidativnog stresa i RAS u procesima progresije FSGS još je nedovoljno razjašnjena. Stoga su istraživanja u okviru ove disertacije bila usmerena ka ispitivanju efekata hronične primene tempola (sakupljač slobodnih radikala, SOD mimetik), losartana (blokator receptora za angiotenzin II tipa 1, AT1R), kao i njihove kombinacije, na usporavanje progresije FSGS izazvane adrijamicinom (ADR) kod spontano hipertenzivnih (SH) pacova. Životinje su inicijalno deljene u dve eksperimentalne grupe, kontrolnu (SHC) i grupu koja je primila ADR 2 mg/kg i.v. dva puta u intervalu od 21 dan. Nakon druge injekcije ADR, životinje su dobijale vodu (SHADR), losartan (SHADR+L), tempol (SHADR+T) i kombinovani tretman (SHADR+T+L) gavažom. Na kraju šeste nedelje tretmana vršena su hemodinamska merenja i uzorkovanje krvi, urina i bubrega. Na osnovu biohemijskih parametara vršena je procena lipidnog statusa i bubrežne funkcije. Urađena je histopatološka analiza bubrega. Imunihistohemijskom metodom ispitivani su proteini citosketeta, nestin i vimentin, čije izmenjene ekspresije su pokazatelj oštećenja bubrežnog tkiva. Matriksna metaloproteinaza-1 (MMP-1), koja učestvuje u degradaciji komponenti vanćelijskog mariksa i očuvanju integriteta glomerula, određivana je ELISA metodom. Ispitivani su parametri oksidativnog stresa: lipidna peroksidacija i nivo karbonilovanih proteina (PCOs); aktivnosti enzima antioksidativnog sistema: superoksid dismutaze (SOD), katalaze (CAT), glutation peroksidaze (GPx) i glutation reduktaze (GR); kao i antioksidativni kapacitet. Primenom imunohistohemijske, Western blot i ELISA metode u bubrezima su određivane ekspresije Nox2 i Nox4 izoforme katalitičke subjedinice NADPH oksidaze, glavni izvor reaktivnih kiseonični

BACKGROUND N-linked glycosylation, which is a post-translational modification process, plays an important role in protein folding, intracellular trafficking and membrane targeting, as well as in regulating the protein function. Recently, we identified a missense variant (p.T141L) in the short isoform 2 of the X-linked gene asparagine-linked glycosylation 13 (ALG13-is2), which segregated with focal segmental glomerulosclerosis and PCCD in a large Australian pedigree; however, any evidence of its pathogenicity was demonstrated. ALG13 gene encodes, through alternative splicing, 2 glycosyltransferase isoforms, which catalyse the second sugar addition of the highly conserved oligosaccharide precursor in the endoplasmic reticulum (ER). Mutations in the long isoform 1 were associated with epilepsy. METHODS AND RESULTS Here, we show a different expression of the 2 isoforms depending on the tissue. Specifically, the long isoform is highly expressed in lungs, ovaries, testes, cerebellum, cortex, retina, pituitary gland, and olfactory bulbs, while the short isoform is highly expressed in mouse podocytes and in human podocyte cell lines, at both mRNA and protein levels. The silencing of ALG13-is2 by specific siRNAs induces an altered N-linked glycosylation pattern of nephrin, as demonstrated by the presence of an additional immunostaining band of about 130 kD. In knock-down cells, immunofluorescence analysis shows perturbed organization of the cytoskeleton and altered localization of nephrin on the cellular membrane. We also demonstrated that the altered pattern of N-linked glycosylation induces an over-expression of binding immunoglobulin protein and calreticulin, suggesting ER stress. CONCLUSIONS These results provide preliminary evidence that ALG13-is2 could be an important modifier of renal filtration defects.

Focal segmental glomerulosclerosis (FSGS) is the most frequent acquired renal condition resulting in end stage kidney disease in children. We describe a cell therapy treatment with human allogeneic bone marrow mesenchymal stem cells (MSC) in a 13-year-old patient developing recurrent FSGS after renal transplantation, which was not responding to conventional therapy. This treatment relied on the following measurements:clinical and laboratory evaluation of renal function, proteome array, biopsy, short tandem repeat assay. Before MSC treatment, the patient needed weekly plasmapheresis to achieve proteinuria-to-creatininuria ratio below 5. After three MSC infusions without adverse events, the patient has a stable renal function and the proteinuria target was reached without plasmapheresis. In addition, some circulating inflammatory factors decreased and their levels were still low after one year. This is the first report of an MSC treatment in an FSGS patient. Even though different factors may have contributed to the clinical results, after MSC infusion a stable reduction in the serum level of several inflammatory factors has been registered and the patient does not need anymore plasmapheresis to keep proteinuria under control. In addition, this encouraging single case let us identify some putative efficacy biomarkers that could be of clinical interest in chronic kidney diseases

A 50-year-old woman with a 1-month history of lower extremity edema and a 5 kg weight increase was admitted to our hospital with suspected nephrotic syndrome in October 1999. Urine protein level was 3.5 g per day, 10-15 erythrocytes in urine per high-power field, and serum albumin level 2.5 g/dl. Furthermore, an accumulation of pleural effusion was confirmed by chest X-ray. The results of a renal biopsy indicated slight mesangial proliferation in the glomeruli by light microscopy, and an immunofluorescence study confirmed the deposition of immunoglobulin (Ig) A and C3 in the mesangial area. Diffuse attenuation of foot processes and dense deposits in the mesangial area were observed by electron microscopy. Treatment with 40 mg/day of prednisolone was effective, and proteinuria was negative 1 month later. Because of this course, we diagnosed minimal change nephrotic syndrome complicated by mild-proliferative IgA nephropathy. In November 2000, there was a relapse of nephrotic syndrome, which was believed to be induced by an influenza vaccination, but response to increased steroid treatment was favorable, and proteinuria disappeared on day 13 of steroid increase. A second relapse in May 2001, showed steroid resistance with renal insufficiency, and an increase in the selectivity index to 0.195. Light microscopy revealed focal sclerotic lesions of the glomeruli, and an immunofluorescence study revealed attenuation of mesangial IgA and C3 deposition. These findings led to the diagnosis that minimal change nephrotic syndrome had transitioned to focal segmental glomerulosclerosis, whereby mesangial IgA deposition was reduced by immunosuppressive treatment. Subsequently, her renal function gradually worsened to the point of end-stage renal failure by 27 months after the second relapse of nephrotic syndrome., Clinical and Experimental Nephrology, 16 (3), pp. 473-479; 2012

A 26-year-old male experienced a recurrence of idiopathic focal segmental glomerulosclerosis (iFSGS) after his second renal transplant. Reduction of proteinuria was rapidly induced by plasmapheresis (PP) and the patient has remained in remission with a once-weekly PP regimen, which has now been continued for >3 years. We were also able to induce remission of iFSGS in this patient by treatment with high cut-off haemodialysis using the Theralite™ dialyser. This observation lends support for the pathophysiological role of an as yet unknown, circulating glomerular filtration barrier permeability factor with an estimated weight of between 30 and 50 kDa.

A 24-year-old man with primary focal segmental glomerulosclerosis (FSGS) with severe tubulo-interstitial change is reported. He was first noticed to have proteinuria on an annual medical checkup at his school in June, 1986. He was referred to our hospital for evaluation of proteinuria. The laboratory tests revealed moderate proteinuria (1.8 g/day) and normal renal function. The renal biopsy showed mild mesan- gial proliferative glomerulonephritis with mild tubulo-interstitial change. As his renal function gradually declined, the second biopsy was performed in November, 1990. Tubulo -interstitial change got worse compared to the first biopsy. Because creatinine clearance was gradually decreasing (57ml/min in July 1993), the third biopsy was performed. The biopsy specimen contained 12 glomeruli, of which only one showed segmental sclerosis. Then a diagnosis of idiopathic focal segmental glomerulosclerosis was made 7 years after manifestation of proteinuria. This case suggests that in FSGS tubulo-interstitial change advances more conspicuously than glomeruli do, and that it takes long duration to make a diagnosis.

A 24-year-old man with primary focal segmental glomerulosclerosis (FSGS) with severe tubulo-interstitial change is reported. He was first noticed to have proteinuria on an annual medical checkup at his school in June, 1986. He was referred to our hospital for evaluation of proteinuria. The laboratory tests revealed moderate proteinuria (1.8 g/day) and normal renal function. The renal biopsy showed mild mesan- gial proliferative glomerulonephritis with mild tubulo-interstitial change. As his renal function gradually declined, the second biopsy was performed in November, 1990. Tubulo -interstitial change got worse compared to the first biopsy. Because creatinine clearance was gradually decreasing (57ml/min in July 1993), the third biopsy was performed. The biopsy specimen contained 12 glomeruli, of which only one showed segmental sclerosis. Then a diagnosis of idiopathic focal segmental glomerulosclerosis was made 7 years after manifestation of proteinuria. This case suggests that in FSGS tubulo-interstitial change advances more conspicuously than glomeruli do, and that it takes long duration to make a diagnosis.

A 24-year-old man with primary focal segmental glomerulosclerosis (FSGS) with severe tubulo-interstitial change is reported. He was first noticed to have proteinuria on an annual medical checkup at his school in June, 1986. He was referred to our hospital for evaluation of proteinuria. The laboratory tests revealed moderate proteinuria (1.8 g/day) and normal renal function. The renal biopsy showed mild mesan- gial proliferative glomerulonephritis with mild tubulo-interstitial change. As his renal function gradually declined, the second biopsy was performed in November, 1990. Tubulo -interstitial change got worse compared to the first biopsy. Because creatinine clearance was gradually decreasing (57ml/min in July 1993), the third biopsy was performed. The biopsy specimen contained 12 glomeruli, of which only one showed segmental sclerosis. Then a diagnosis of idiopathic focal segmental glomerulosclerosis was made 7 years after manifestation of proteinuria. This case suggests that in FSGS tubulo-interstitial change advances more conspicuously than glomeruli do, and that it takes long duration to make a diagnosis.