Microscopic polyangiitis (MPA) is an anti-neutrophil cytoplasmic antibody (ANCA) associated systemic small vessel vasculitis and is uncommon in children.Pathologically characterized by paucity immune deposition,fibroid necrosis and crescent formation in glomeruli.MPA is a multi-organ involvement disease.Renal is the mostly involved and commonly manifested as aggressive glomerulonephritis.Lung is the most common involved extrarenal organ.Most MPA patients have positive myeloperoxidase-ANCA and positive perinuclear-ANCA.The onset of MPA is usually obscure,which makes early diagnosis difficult.Detection of ANCA is performed in order to discriminate suspected MPA patients earlier.Confirmed diagnosis relies on pathology.Early standardized treatment is a key factor in prognosis.Standard inductive treatment is currently the combination of corticosteroids with the cytotoxic agent cyclophosphamide.Azathioprine is suggested as the first-choice medication in maintenance therapy.Bio-agents,such as Rituximab,have shown good curative effect both in the inductive treatment and maintenance therapy.

AIM:To study whether albumin overload in proximal tubular epithelial cells(PTCs)induces epithelial to myofibroblast transdifferentiation(EMT).METHODS:Rat renal proximal tubular cell line NRK52E was cultured on 6 well plates.When the cells reached 70% confluens or complete confluens,cells were serum starved for 24 h.Different concentrations of delipidated bovine serum albumin(dBSA),ranging from 0-30 g/L,were then added to the cells.The media was changed every 48 h until the end of 144 h.Cell shapes were monitored by light microscope during experiment.Cell structures were detected by electron microscopy.Epithelial cell markers:E-cadherin,?-catenin,and myofibroblast marker:?-smooth muscle actin(?-SMA)were detected by immunofluorescent microscopy and Western blotting.RESULTS:dBSA overload induced the expression of ?-SMA in sub-confluent NRK52E,and a few cells elongated,but the induced expression of ?-SMA was not in a dose dependent manner.dBSA overload did not induce the expression of ?-SMA in complete confluent NRK52E,cell shape did not change either.dBSA overload did not inhibit expression of E-cadherin or ?-catenin both in sub-confluent and complete confluent NRK52E.The electron microscope showed that these cells retained epithelial phenotype,with microvilli and tight junction.CONCLUSION:Albumin overload induces PTCs expressing myofibroblast marker ?-SMA and promotes EMT.However,complete EMT does not achieve.Complete confluens(cell-cell contacts)inhibits albumin induced ?-SMA expression in PTCs.

[Objective] To observe the effect of cyclosporine A (CSA) on the activity and expression of MMP-2 and MMP-9 in renal tubular epithelial cells. [Methods] NRK52E cells were cultured until its reached confluent. Then NRK52E cells were exposed to different concentration of CSA (0, 0.42, 0.84, 4.2, and 8.4 μmoL/L) for 48 h or 72 h respectively. MMP-2 and MMP-9 activities were detected by gelatin zymography. The expression of MMP-2 and MMP-9 mRNA were detected by RT-PCR. [Results] MMP-2 activity and mRNA levels were decreased in a dose dependent manner after exposed to different concentration of CSA for 48 h or 72 h in NRK52E cells. Compared with control (CSA 0 μmoL/L), CSA 0.42, 0.84, 4.2, 8.4 μmoL/L decreased the MMP-2 activities to 27%, 24%, 11%, and 9% respectively; The differences are significant, P<0.05. But the MMP-9 activity and mRNA levels were increased after exposed to CSA for 48 h or 72 h in NRK52E cells. Compared with control group, CSA 4.2 μmoL/L exposure increased MMP-9 activity to 438% in 48 h, and 237% in 72 h; the differences are significant as well, P<0.05. [Conclusion] A dose-dependent decrease in the expression and activity of MMP-2, and the up-regulation of the expression and activity of MMP-9 by CSA in renal epithelial cells may related to CSA associated tubulointerstitial damage.

OBJECTIVE: To explore the genetic basis for a child presented with renal failure and multi-cystic dysplastic kidney without anal atresia. METHODS: Peripheral blood sample of the child and his parents were collected and subjected to whole exome sequencing. Candidate variant was verified by Sanger sequencing. RESULTS: The 40-day-old infant had presented with vomiting brown matter in a 7 days neonate and was transferred for kidney failure. Clinical examination has discovered renal failure, polycystic renal dysplasia, congenital hypothyroidism, bilateral thumb polydactyly, sensorineural hearing loss and preauricular dermatophyte. Genetic testing revealed that he has harbored a previously unreported c.824delT, p.L275Yfs*10 frameshift variant of SALL1 gene, which was confirmed by Sanger sequencing as de novo. CONCLUSION The patient was diagnosed with Townes-Brocks syndrome due to the novel de novo variant of SALL1 gene. Townes-Brocks syndrome without anal atresia is rare. Above finding has also enriched the mutational spectrum of the SALL1 gene.
Abnormalities, Multiple ; Anus, Imperforate/genetics* ; Child ; Female ; Hearing Loss, Sensorineural/genetics* ; Humans ; Infant ; Infant, Newborn ; Male ; Renal Insufficiency ; Thumb/abnormalities* ; Transcription Factors/genetics*

Objective: To explore the clinical and pathological features and mutational types and their relations with WT1 mutation-associated nephropathy (WT1MAN). Methods: The clinical and pathological data and the results of WT1 mutation analysis of the cases from Nanfang Hospital of Southern Medical University, Sun Yat-sen Memorial Hospital and The First Affiliated Hospital of Sun Yat-sen University whom we recruited recently and reported during the last ten years were analyzed. Results: Totally, 20 cases (6 males and 14 females), included 5 newly diagnosed cases, were recruited. (1) Ten children were diagnosed with Denys-Drash syndrome (DDS): The median onset age of proteinuria was 1 year and 7 months. Diffuse mesangial sclerosis (DMS) were revealed in 3 cases, minimal lesions (MCD) in 4 cases, and focal segmental glomerulosclerosis (FSGS) in 1 case; renal pathology was not available in the other 2 cases. Glomerular basement membrane (GBM) thickening was observed in 2 cases. Calcineurin inhibitors (CNIs) were administered in 5 cases, complete remission of proteinuria was observed in 3 cases, partial remission in the other 2 cases. Genetic analysis revealed that six cases had WT1 missense mutation, 3 had nonsense mutation, and 1 had frameshift mutation. (2) Two cases were diagnosed with Frasier syndrome (FS): proteinuria was observed at 1 year and 1 month of age and 1 year and 9 months of age, respectively. FSGS with GBM layering were observed in both cases. They progressed to ESRD at 1 year and 6 months of age and 6 years and 6 months of age, respectively. CNI was tried in 1 case with partial proteinuria remission. Both patients were detected to have WT1 splice mutation. (3) Isolated nephropathy (IN) was observed in 8 cases: three had splice mutation, 5 had missense mutation. Of the 3 patients with splice mutation, one was found to have nephropathy and renal failure at the age of 5 months. The other two cases (1 was FSGS and another MCD), both had GBM layering. CNIs were tried on both of them, one got partial remission with normal renal function at the age of fourteen years, the other one had no response and entered ESRD at the age of 6 years and 9 months. Of the 5 cases with missense mutation, 3 had DMS, 2 of them entered ESRD within 6 months of age, another case had DMS entered ESRD at 9 years of age. One case with FSGS, was treated with CNIs and got complete remission. Conclusions Slow progression (7/10) nephropathy was observed in DDS patients. Missense mutation (11/20) was the most common type of WT1 variants, followed by splice mutation (5/20) in this group of patients. Early onset nephropathy (4/5), rapid progression (4/5) and GBM layering (4/4) wereobserved in patients with splice mutation. CNI was effective in reducing or even eliminating proteinuria in WT1 MAN patients (8/9).

Objective:To explore the characteristics of Lowe syndrome, as well as OCRL1 gene mutation and its relationship with phenotype. Methods:Children diagnosed with Lowe syndrome during their visit to Nanfang Hospital of Southern Medical University (4 cases) and the First Affiliated Hospital of Sun Yat-sen University (3 cases) from January 2009 to January 2019 were included. The clinical data and peripheral blood samples were collected, and the sequence analysis of OCRL1 was performed after genomic DNA extraction. Then the clinical features of the children and the relationship between OCRL1 mutation and clinical phenotype were analyzed. Results:Seven patients from 6 families who presented with Lowe syndrome were included. All of them had different degrees of ocular-neural-renal symptoms. Six cases from 5 families had congenital cataract and neonatal hypotonia, one case from another family only had a thin lens without cataract. Four cases had nystagmus and 2 cases had glaucoma. Six cases from 6 families had psychomotor retardation and had proximal tubular impairment, included low-molecular-weight proteinuria (LMWP). Serum aspartate transaminase (AST), lactate dehydrogenase (LDH), creatine kinase (CK) and creatine kinase-MB (CK-MB) were increased in all 6 patients who were tested. Mutations of OCRL1 were detected in all the 6 families, which located in exon 10, 13, 16, 18, 22 and 23 respectively. The mutations of c.891 G>T, c.1682_1683insAA and c.2564_2567del are novel. Conclusions:Three OCRL1 novel mutations in 6 Chinese Lowe syndrome families are identified. The clinical manifestations in different mutations of OCRL1 are heterogeneous. The mutations of c.891 G>T in exon 10 without congenital cataract is rare in clinical.

Objective To explore the impacts of NPHP1 knockdown on the phenotype of Madin-Darby canine kidney (MDCK) cells. Methods The expression of NPHP1 in MDCK cells was knockdown by siRNA interference. Cells were divided into normal control group, negative control group and siRNA group. The cellular morphology and migration were observed by light microscope. The mRNA expressions and activities of matrix metalloproteinases 2 and 9 (MMP2 and MMP9) were detected by real time PCR and gelatin zymography. The mRNA and protein expressions of E-cadherin, β-catenin, zonula occluden-1 (ZO-1), ZO-1-associated nucleic acid binding protein (ZONAB) and α-smooth muscle actin (α-SMA) were analyzed by real time PCR, Western blotting and immunocytochemistry. Results Compared with those in normal control group, in siRNA group the mRNA expressions of E-cadherin, β-catenin and ZO-1 decreased, and MMP9, MMP2, α-SMA and ZONAB increased after interfering NPHP124 h (all P<0.05); the protein expressions of E-cadherin,β-catenin and ZO-1 decreased and ZONAB and α-SMA increased after 48 h (all P<0.05), and MDCK cells became elongated with enhanced migration capacity; siRNA cells had decreased expressions of E-cadherin and β-catenin on the membrane, but increased expression of ZONAB in cytoplasm and nucleoplasm after 72 h, and α-SMA was also observed in some interfered cells. Conclusions NPHP1 knockdown induces epithelial-mesenchymal transition in MDCK cells, and ZO-1/ZONAB signaling pathway was activated. These changes may associate with renal interstitial fibrosis of Nephronophthisis type I.

OBJECTIVE To develop a population pharmacokinetic （PPK） model for mycophenolate mofetil active metabolite mycophenolic acid （MPA） in children with primary IgA nephropathy， explore the factors affecting the pharmacokinetic parameters of MPA， and provide a basis for clinical individualized therapy. METHODS Retrospective collection was conducted on 636 concentrations and clinical data from 47 pediatric patients with primary IgA nephropathy. PPK analysis was carried out by using the nonlinear mixed-effects model； the covariates were tested with a stepwise method. Goodness-of-fit plots， Bootstrap and visual predictive check were employed to evaluate the final model. RESULTS The pharmacokinetics of MPA in children with IgA nephropathy in vivo conformed to the first-order absorption and elimination two-compartment model （objective function value of 3 276.31）. Covariate analysis suggested that body weight and albumin （ALB） levels were significant influencing factors on apparent clearance rate and apparent distribution volume. The typical values of PPK parameters of MPA in the final model were as follows： the central room had a distributed volume of 5.79 L， the clearance rate was 4.06 L/h， the volume of peripheral ventricular distribution was 430.93 L， the clearance rate between compartments was 15.40 L/h， the oral absorption rate constant was 1.29 h－1. After verification， most of the predicted corrected observed concentration points were within the 90% confidence interval of the predicted corrected simulated concentration， indicating that the MPA final model had good predictive performance. CONCLUSIONS The PPK model of MPA in children with primary IgA nephropathy is established in this study， identifying body weight and ALB levels are significant factors affecting MPA metabolism.