Hydroxychloroquine Ameliorates Hematuria in Children with X-Linked Alport Syndrome: Retrospective Case Series Study.

Purpose: As a rare collagen type IV hereditary kidney disease, X-linked Alport syndrome (XLAS) is the most common form of Alport syndrome, the prevalence of which is estimated at 1:10,000 of the population, four times higher than the prevalence rate of autosomal recessive Alport syndrome. To describe a series of eight XLAS children with persistent hematuria and proteinuria and the clinical outcomes after hydroxychloroquine (HCQ) treatment to assess its efficacy as early intervention. Patients and Methods: The study retrospectively analysed 8 patients with persistent hematuria and proteinuria at different onset ages who were diagnosed with XLAS and been treated with HCQ. The urinary erythrocyte count, urinary albuminn were measured. Descriptive statistics were used to estimate the patients' responses to HCQ treatment after one month, three months, and six months. Results: After the first month, the three months, and the six months of HCQ treatment, the urinary erythrocyte counts of four, seven, and eight children were significantly reduced; the decreasing proteinuria was found in two, four, and five children. Only one child with increasing proteinuria was found after 1-month HCQ treatment. This proteinuria was maintained after 3-month HCQ treatment but decreased to minor after 6-month HCQ treatment. Conclusion: We present the first potential efficacy of HCQ treatment in XLAS with hematuria and persistent proteinuria. It suggested that HCQ could be an effective treatment to ameliorate hematuria and proteinuria.

Determination of the pathogenicity of a novel COL4A5 missense variant by CRISPR-Cas9 in kidney podocytes.

OBJECTIVE: The main purpose of this research was to investigate the influence of the novel COL4A5 missense mutation on collagen type IV. METHODS: Clinical data and detailed family history were collected. Targeted next-generation sequencing (NGS) was applied to examine potential pathogenic variants in COL4A3, COL4A4, COL4A5 genes in the proband, and then the variants were analyzed using bioinformatics tools and pedigree analysis. The CRISPR/Cas9 gene editing was used to knock in potential pathogenic variants in human podocytes, and then western blot analyses and immunofluorescence assays were used to measure COL4A5 protein expression. RESULTS: Three patients (I: 2, II: 1 and II: 2) presented with microscopic hematuria and proteinuria, and the patient II: 1 progressed to abnormal renal function by age 14. A novel missense variant, c.2641G>A (p. Gly881Arg), located in exon 31 of COL4A5 gene, was chosen as a possible pathogenic variant. The variant significantly decreased collagen IV α5 chain expression in CRISPR/Cas9 gene edited podocytes. CONCLUSION: By conducting NGS and CRISPR/Cas9 gene-editing of podocytes, a novel COL4A5 missense variant, c.2641G>A (p. Gly881Arg), was confirmed to be the genetic defect of X-linked Alport syndrome in the Chinese family. Our findings extend the genetic spectrum of X-linked Alport syndrome with COL4A5 mutations and provide a method for evaluating the functional significance of novel COL4A5 missense variants in vitro.

Generation of an induced pluripotent stem cell line (SHCDNRi001-A) from a patient with X-linked Alport syndrome carrying a heterozygous p.G409S (c. 1225 G > A) mutation in the COL4A5 gene.

X-linked Alport syndrome (XLAS) is a rare form of hereditary nephritis caused by mutations in the COL4A5 gene encoding the type IV collagen α5 chain. A skin biopsy was performed on one female patient with XLAS who carried a heterozygous p.G409S (c. 1225 G > A) mutation in the COL4A5 gene. A human-induced pluripotent stem cell (iPSC) line was generated from dermal fibroblasts using the integrating free Sendai virus technique. The generated iPSC line SHCDNRi001-A offers an efficient resource to research pathogenic mechanisms in XLAS, as well as a cell-based disease model for drug testing or other treatments.

Value of micro-proteinuria in combination with ultrasonography of the left renal vein in the diagnosis of orthostatic proteinuria.

BACKGROUND: This study aimed to evaluate the clinical value of micro-proteinuria in combination with ultrasonography of the left renal vein (LRV) in the diagnosis of orthostatic proteinuria (OP). METHODS: The patients with suspected OP received West test, upright lordotic position test, Robinson test, ultrasonography of the LRV, and detection of morning urine micro-proteinuria and micro-proteinuria after activity. The sensitivity (Se), specificity (Sp), positive and negative predictive values (PPV and NPV), positive and negative likelihood ratios (PLR and NLR) and Youden's index (YI) for micro-proteinuria, ultrasonography of the LRV and both of them in the diagnosis of OP were analyzed. RESULTS: From January 2013 to January 2018, 75 patients (M/F: 38/37) were recruited. Sixty patients were diagnosed with OP (M/F: 29/31, median age at onset: 10.6±2.80 years); 15 patients had no OP (M/F: 9/6, median age at onset: 10.9±3.25 years); the LRV entrapment, urine Alb/Cr, IgG/Cr, and NAG/Cr after activity were significantly different between OP group and non-OP group (Z=-3.55, -4.10, -4.01, -3.04, P<0.05). The area under the curve (AUC) of urine Alb/Cr, IgG/Cr, NAG/Cr, and the ratio of anteroposterior (AP) for LRV in the hilar and narrow portions (a/b) was 0.84, 0.84, 0.76 and 0.58, respectively, and the best cut-off value was 13.2 mg/mmol, 2.52 mg/mmol, 0.64 U/mmol and 4.06, respectively. The combination of ultrasonography of the LRV and elevated micro-proteinuria after activity could achieve the Se, Sp, PPV, NPV, PLR (weighted by prevalence, W), NLR (W) and YI at 93.3% (95% CI: 0.83-0.98), 66.7% (95% CI: 0.39-0.87), 91.8% (95% CI: 0.81-0.97), 71.4% (95% CI: 0.42-0.90), 11.2 (95% CI: 4.82-26.00), 0.40 (95% CI: 0.17-0.97) and 60%, respectively, in the diagnosis of OP. CONCLUSIONS: The micro-proteinuria in combination of ultrasonography of the LRV is helpful for the preliminary screening of OP in patients with suspected OP.

Chylopericardium in a child with IgA nephropathy: a case report.

BACKGROUND: Chylopericardium effusion is characterized by the accumulation of milky effusion in the pericardium. It is often idiopathic but it can be secondary to trauma, chest radiation, tuberculosis and malignancy. If cardiac tamponade ensues, it becomes life-threatening. Herein we describe chylopericardium tamponade in a child with IgA nephropathy. To the best of our knowledge, this is the first reported case of chylopericardium tamponade in IgA nephropathy. CASE PRESENTATION: A 6 years old boy with IgA nephropathy presented with dyspnea, orthopnea, pretibial pitting edema, ascites and fever. Muffled heart sounds and hepatomegaly were also noted. Echocardiography and thoracic CT revealed that there was a large volume of hydropericardium. Moreover, the pericardial milky fluid by pericardiocentesis was analyzed and chylopericardium effusion was eventually confirmed. Pericardial drainage was continued and his diet was modified to low fat, rich MCT and high protein. Complete remission was achieved after 3 weeks of this combined treatment. CONCLUSION: Chylopericardial tamponade could be a rare and life-threatening complication of IgA nephropathy. Etiological analysis is critical for determining the therapeutic approach in patients with pericardial effusion.

P53 inhibitor pifithrin-α prevents the renal tubular epithelial cells against injury.

The injury and repair of renal tubular epithelial cells play an important role in the pathological process of acute kidney injury (AKI). This study aimed to clarify the role of cell cycle change in renal tubular epithelial cell injury and repair in vivo and in vitro. Sprague-Dawley rats received bilateral renal pedicle clamping for 45 min (ischemia) followed by reperfusion. Pifithrin-α, a p53 inhibitor, was administered at 24 h before renal ischemia and 3 and 14 days after reperfusion. Results showed the tubular epithelial cells in M phase increased significantly at 2 h to 72 h after ischemia/reperfusion (I/R), while pifithrin-α decreased them. Renal I/R caused renal tubular epithelial damage in rats, which was improved by pifithrin-α. The α-SMA mRNA expression was up-regulated significantly after I/R, while it was down-regulated by pifithrin-α.NRK-52E cells were cultured in vitro, cell damage was induced by addition of TNF-α, and then cells were treated with pifithrin-α. Cells treated with TNF-α alone in G2/M phase increased significantly, but they were reduced in the presence of pifithrin-α. In NRK-52E cells treated with pifithrin-α for 6 h, NGAL mRNA expression was significantly lower than in cells without pifithrin-α treatment. After NRK-52E cells were treated with pifithrin-α for 24 h, α-SMA and FN mRNA expression was significantly lower than in cells without the treatment. In summary, pifithrin-α can facilitate the progression of renal tubular epithelial cells through G2/M phase, protecting them against injury.

Single dose of rituximab in children with steroid-dependent minimal change nephrotic syndrome.

Rituximab (RTX) can be used in children with nephrotic syndrome, particularly in those with steroid-dependent nephrotic syndrome (SDNS). However, at present there is no unified standard of how to use RTX, with regard to the amount of doses and frequency, in children with nephrotic syndrome. The study aimed to investigate the therapeutic efficacy of a single dose of RTX in children with steroid-dependent minimal change nephrotic syndrome (SD-MCNS). The patients with biopsy-proven minimal change disease (MCD) and clinical features of SDNS received a single dose of RTX (375 mg/m2). The toxicity and side effects of RTX were also observed. The study included 19 patients (10 males and 9 females). Follow-up of the patients was 1-50 months (28.1±16.6 months). B-cell depletion was achieved with RTX infusion (CD20<0.5%) and lasted 1-6 months (mean, 2.92±1.57 months). During follow-up, 10 patients remained in complete remission and did not relapse without administration of oral steroids or immunosuppressants for 4-50 months (mean, 30.1±12.6 months), despite recovery of the B-cell count. Nine patients relapsed in the process of reducing steroids, thus, treatment was maintained at a lower dosage (T=0, P<0.05) than prior to use of RTX. The number of relapses also decreased significantly (T=95, P<0.05). Five of the patients relapsed after stopping steroid for several months. At the end of follow-up, the efficacy of a single induction of RTX was 47.4% (9/19). There were no significant side effects associated with administration of RTX. In conclusion, RTX is a safe and effective alternative for children with SD-MCNS. RTX is an effective treatment for the rapid induction of remission and reduces relapse and steroid dependency. A single dose of RTX for children with SD-MCNS is recommended for rapid induction of remission, reduction of long-term steroid dosage, and decrease in the number of relapses, as it has few side effects.

Response gene to complement 32 regulates the G2/M phase checkpoint during renal tubular epithelial cell repair.

BACKGROUND: The aim of this study was to evaluate the influence of RGC-32 (response gene to complement 32) on cell cycle progression in renal tubular epithelial cell injury. METHODS: NRK-52E cells with overexpressed or silenced RGC-32 were constructed via transient transfection with RGC-32 expression plasmid and RGC-32 siRNA plasmid, and the cell cycle distribution was determined. The expression levels of fibrosis factors, including smooth muscle action (α-SMA), fibronectin (FN) and E-cadherin, were assessed in cells with silenced RGC-32. RESULTS: The cells were injured via TNF-α treatment, and the injury was detectable by the enhanced expression of neutrophil gelatinase-associated lipocalin (NGAL). RGC-32 expression also increased significantly. The number of cells at G2/M phase increased dramatically in RGC-32 silenced cells, indicating that RGC-32 silencing induced G2/M arrest. In addition, after treatment with TNF-α, the NRK-52E cells with silenced RGC-32 showed significantly increased expression of α-SMA and FN, but decreased expression of E-cadherin. CONCLUSIONS: The results of this study suggest that RGC-32 probably has an important impact on the repair process of renal tubular epithelial cells in vitro by regulating the G2/M phase checkpoint, cell fibrosis and cell adhesion. However, the exact mechanism needs to be further elucidated.

254C>G: a TRPC6 promoter variation associated with enhanced transcription and steroid-resistant nephrotic syndrome in Chinese children.

BACKGROUND: Mutations in canonical transient receptor potential channel 6 (TRPC6) have been identified as responsible for the development of focal segmental glomerulosclerosis, a proteinuric disease with steroid resistance and poor prognosis. This study explores the prevalence of TRPC6 variants in Chinese children with idiopathic nephrotic syndrome (INS), the genotype/phenotype correlation of TRPC6 variants, the therapeutic response, and the underlying molecular mechanism. METHODS: Fifty-one children with sporadic INS were enrolled: 23 steroid-sensitive cases and 28 steroid-resistant cases Polymerase chain reaction was used to amplify 13 exons and the promoter sequences of TRPC6 before sequencing. The expression of TRPC6 in renal tissues was illustrated by immunohistochemistry staining. The transcriptional activity of variants in TRPC6 promoter was measured by the luciferase assay. RESULTS: Three variants (-254C>G, rs3824934; +43C/T, rs3802829; and 240 G>A, rs17096918) were identified. The allele frequency of the -254C>G single-nucleotide polymorphism (SNP) in the steroid-resistant nephrotic syndrome (SRNS) patients (40.5%) was higher than that in the steroid-sensitive nephrotic syndrome subjects (27.1%; P = 0.046). The -254C>G SNP enhanced transcription from TRPC6 promoter in vitro and was associated with increased TRPC6 expression in renal tissues of SRNS patients. CONCLUSION: -254C>G, a SNP underlying enhanced TRPC6 transcription and expression, may be correlated with the development of steroid resistance in Chinese children with INS.

Follow-up results of children with melamine induced urolithiasis: a prospective observational cohort study.

BACKGROUND: Melamine-contaminated milk powder was the cause of the 2008 outbreak of urolithiasis in young children and infants in China, but the prognosis of these children remains unknown. We hypothesized that urolithiasis induced by melamine-contaminated milk powder may be associated with secondary renal injury. METHODS: A total of 8335 children (≤6 years old) with a history of consuming melamine-contaminated milk powder were screened. Urine analysis and urinary system ultrasonography were performed. For children with urolithiasis, the basic information and the results of examination were recorded, and effective therapy was given. They were followed up for 6 months after the original diagnosis, and urinary microprotein profiles were measured. RESULTS: Of the 8335 children, 105 (1.26%) were diagnosed with melamine-contaminated milk powder-associated urolithiasis. The size of the stone was correlated with the duration of exposure to melamine. Six months later, 69.8% (67) of the children with urolithiasis passed stones (follow-up rate: 91.4%). Of the 67 children, 28 passed stones within 2 months. The higher possibility of passing a stone was correlated with the smaller diameter of the stone (P<0.001). The detection rate of abnormal urinary microprotein excretion (microalbumin, immunoglobulin G, and N-acetyl-ß-D-glucosidase) was 52.4% in children with persistent stones and 38.2% in those who passed their stones. The detection rate was lower in children who passed stones within 2 months (31.8%) than in those who passed stones in 2 to 6 months (50.0%). The levels of microalbumin/creatinine and immunoglobulin G/creatinine were significantly higher in children with persistent stones than in those who passed their stones. CONCLUSIONS: Early passage of a stone may reduce the renal injury induced by melamine-contaminated milk powder-associated urolithiasis.

Expression of response gene to complement-32 in renal tissue of children with immunoglobulin A nephropathy.

OBJECTIVE: This study aimed to investigate the expression and significance of response gene to complement-32 (RGC-32) in renal tissue of children with immunoglobulin A nephropathy (IgAN). MATERIAL AND METHODS: Forty-five patients diagnosed as having IgAN by renal biopsy were enrolled. The expression of RGC-32, α-smooth muscle actin (α-SMA) and transforming growth factor-ß(1) (TGF-ß(1)) was observed by immunohistostaining. The relationshis between the expression of RGC-32, α-SMA, TGF-ß1, degree of renal pathological lesions in IgAN and clinical index were assessed by Spearman correlation. RESULTS: Immunohistostaining analysis showed that RGC-32 protein was present in epithelial cells of renal tubules in normal and IgAN renal tissues. With more severe renal pathological lesions, the expression of RGC-32 in IgAN was increased. The expression of RGC-32 was positively correlated with that of α-SMA, TGF-ß(1) and the degree of renal pathological lesions in children with IgAN (p < 0.05), but had no relationship with serum creatinine, urinary N-acetyl-ß-d-glucosaminidase/creatinine, urinary microalbuminuria/creatinine, urinary microimmunoglobulin/creatinine or urinary α(1)-microglobulin/creatinine ratio (p > 0.05). CONCLUSION: Expression of RGC-32 can reflect the degree of renal pathological lesions in IgAN. RGC-32 may participate in the renal tubulointerstitial lesions in children with IgAN, especially in epithelial -mesenchymal transition induced by TGF-ß(1).