Xiqiang Dang

Role of PAX2 gene polymorphisms in Henoch-Schonlein purpura nephritis.

Objective:  To investigate the distribution of polymorphisms in the PAX2 gene in children with Henoch–Schonlein purpura with and without nephritis (HSPN and HSP, respectively), with particular attention to the relationship between PAX2 gene polymorphisms and the development of kidney pathology.

Etiology and outcomes of acute kidney injury in Chinese children: a prospective multicentre investigation

BackgroundThe incidence of AKI appears to have increasing trend. Up to now, prospective, multi-center, large-sample epidemiological study done on pediatric AKI on aspects of epidemiological characteristics, causes and outcomes have not reported. It is necessary to develop prospective, multi-center, large-sample epidemiological study in our country on pediatric AKI. The aim of this study was to determine the clinical features, etiology, and outcomes of acute kidney injury (AKI) in Chinese children.MethodPaediatric patients (≤18 years old) admitted to 27 hospitals (14 children’s hospitals and 13 general hospitals) affiliated with the Medical University were investigated. AKI was defined using the 2005 Acute Kidney Injury Network criteria.ResultsDuring the study period, 388,736 paediatric patients were admitted. From this total, AKI was diagnosed in 1,257 patients, 43 of whom died. The incidence and mortality of AKI was 0.32% and 3.4% respectively. The mean (± SD) age of patients was 48.4 ± 50.4 months. Among the 1,257 AKI paediatric patients, 632 were less than one year old. Among the AKI paediatric patients, 615 (48.9%) were in stage 1, 277 (22.0%) in stage 2, and 365 (29.0%) in stage 3. The most common causes of AKI were renal causes (57.52%), whereas postrenal (25.69%) and prerenal (14.96%) causes were the least common. The three most common causes of AKI according to individual etiological disease were urolithiasis (22.35%), of which exposure to melamine-contaminated milk accounted for the highest incidence (63.7%); acute glomerulonephritis (10.10%); and severe dehydration (7.48%). A total of 43 AKI patients (3.4%) died during their hospital stay; 15 (34.9%) of the 43 died as a result of sepsis.ConclusionPrimary renal diseases are a major risk factor for paediatric AKI in China. In terms of specific etiological disease, urolithiasis (postrenal disease) was the leading cause of paediatric AKI in 2008, when the disease was linked to exposure to melamine-contaminated milk. Sepsis is the leading cause of death in Chinese paediatric AKI patients. Future studies should focus on effective ways of controlling renal disorders and sepsis to improve the clinical management of paediatric AKI in China.

Mutation spectrum of genes associated with steroid-resistant nephrotic syndrome in Chinese children.

Approximately 20% of children with idiopathic nephrotic syndrome do not respond to steroid therapy. More than 30 genes have been identified as disease-causing genes for the steroid-resistant nephrotic syndrome (SRNS). Few reports were from the Chinese population. The coding regions of genes commonly associated with SRNS were analyzed to characterize the gene mutation spectrum in children with SRNS in central China. The first phase study involved 38 children with five genes (NPHS1, NPHS2, PLCE1, WT1, and TRPC6) by Sanger sequencing. The second phase study involved 33 children with 17 genes by next generation DNA sequencing (NGS. 22 new patients, and 11 patients from first phase study but without positive findings). Overall deleterious or putatively deleterious gene variants were identified in 19 patients (31.7%), including four NPHS1 variants among five patients and three PLCE1 variants among four other patients. Variants in COL4A3, COL4A4, or COL4A5 were found in six patients. Eight novel variants were identified, including two in NPHS1, two in PLCE1, one in NPHS2, LAMB2, COL4A3, and COL4A4, respectively. 55.6% of the children with variants failed to respond to immunosuppressive agent therapy, while the resistance rate in children without variants was 44.4%. Our results show that screening for deleterious variants in some common genes in children clinically suspected with SRNS might be helpful for disease diagnosis as well as prediction of treatment efficacy and prognosis.

Nephroprotective effects of subcapsular transplantation of metanephric mesenchymal cells on gentamicin-induced acute tubular necrosis in rats

BackgroundThe subcapsular transplantation of metanephric mesenchymal cells (MMCs) may be a new therapeutic approach for the treatment of acute tubular necrosis (ATN). To investigate this hypothesis and provide evidence for its possible use in the clinic, we evaluated the nephroprotective effects of transplanting MMCs into the renal subcaspsule of rats with ATN induced by gentamicin.MethodsMMCs were expanded in culture. After gentamicin-induced ATN was established, fluorescently-labeled cells were transplanted and traced in kidney tissues by fluorescence microscopy. Serum creatinine (Cr), urea nitrogen (BUN), and N-acetyl-b-D-glucosaminidase (NAG) levels were determined at different time points. Kidney pathology was studied by hematoxylin-eosin staining. Apoptosis was examined by the TUNEL assay.ResultsIn the MMCs-treated group, the mortality rate decreased; BUN, Cr, and NAG levels peaked at 8 days, and were significantly lower than those in the other groups at 11 and 14 days. RIMM-18 cells locally recruited through precise tropism to sites of injury had the ability to migrate into the tubuli from the renal subcapsule. Damage to the cell-treated kidneys was reduced. The pathologic lesion scores of tubular damage reached the highest values at 8 days in the treated kidneys and 11 days in the untreated ones. The apoptotic index showed that the peaks of apoptosis occurred at earlier stages of the injury process in cell-treated than in untreated kidney and thereafter declined in a time-dependent manner.ConclusionThe subcapsular transplantation of MMCs could ameliorate renal function and repair kidney injury.

Association of the paired box 2 gene polymorphism with the susceptibility and pathogenesis of Henoch‑Schönlein purpura in children

The present study aimed to investigate the distribution of paired box 2 (PAX2) gene polymorphisms in healthy populations and in patients with Henoch‑Schönlein purpura (HSP), focusing on the association between PAX2 gene polymorphisms and the susceptibility and clinical characteristics of HSP. Genomic DNA was extracted from the peripheral venous blood of 100 healthy children (mean age: 5 ± 1.9 years) and 118 children with HSP (mean age: 10.2 ± 2.3 years). Polymerase chain reaction (PCR) was used to amplify exons 1‑12 of the PAX2 gene. Denaturing high performance liquid chromatography and DNA sequencing analysis were conducted for screening of mutations in the PAX2 gene in the PCR products. No genetic polymorphism of the PAX2 gene was identified in exons 1‑7, 9, 10 or 12. Two single nucleotide polymorphisms (SNPs), which presented as complete linkage haplotype 798C>T/909A>C, were identified in exon 8. An SNP (1164T>A) was also identified in exon 11. No significant difference in the allele and genotype frequency distribution of exon 8 (798C>T) or 11 (1164T>A) of the PAX2 gene was identified between the HSP and control groups (P>0.05). However, the frequency of the PAX2 heterozygous genotype 798C>T in the HSP with nephritis (HSPN) group was significantly higher than those in the controls and in the HSP without nephritis group (P<0.05). Furthermore, no significant correlation was identified between the PAX2 gene exon 8 polymorphism (798 C>T) and the renal pathology of children with HSPN. An SNP (1164T>A) was identified in exon 11. The PAX2 heterozygous genotype 798C>T did not increase susceptibility to HSP, however, it may be used clinically as a screening indicator for HSP in children with a high risk of renal involvement.

Angiogenic Effect of Endothelial Progenitor Cells Transfected with Telomerase Reverse Transcriptase on Peritubular Microvessel in Five Out of Six Subtotal Nephrectomy Rats

Renal disease is caused by tubular interstitial injury and renal interstitial fibrosis. Previous studies have shown that transplantation of endothelial progenitor cells (EPCs) may provide an appropriate treatment for repair and reversing renal pathology. However, EPCs are typically low in abundance and have poor replication ability. Therefore, the this study investigated the use of EPCs transfected with the telomerase reverse transcriptase (TERT) in rats that had undergone five out of six subtotal nephrectomy. This study determined the effects of EPC transplantation on renal function, renal interstitial fibrosis, and peritubular capillary angiogenesis. Five groups of rats were investigated: sham group, model group (five out of six subtotal nephrectomy), EPCs-N group (transplantation with EPCs), pZ-TERT-EPCs-N group (transplantation with EPCs transfected with TERT), and pZ-EPCs-N group (transplantation with EPCs transfected with empty plasmid). At weeks 4, 8, and 12 after transplantation, renal function, renal interstitial fibrosis, and peritubular microvessel density (MVD) were investigated. EPCs transfected with TERT gene showed decreased in vitro senescence, apoptosis, and proliferative ability was significantly enhanced (p < 0.05). Furthermore, rat transplanted with EPCs transfected with TERT showed significantly reduced renal interstitial fibrosis and increased endogenous creatinine clearance rate and peritubular MVD (p < 0.05). The transplantation of EPCs expressing TERT into five out of six subtotal nephrectomy rats was shown to improve renal function, reduce loss of peritubular microvessel, and inhibit progression of renal interstitial fibrosis. These studies provide the basis for a potential treatment of renal disease using genetically modified EPCs.

Genetic analysis of a 12-year-old boy with X-linked ichthyosis in association with sclerosing glomerulonephritis.

In this study, we report the case of a 12-year-old male with X-linked ichthyosis (XLI) in association with glomerular sclerosis, and our investigation into the deletion pattern of the STS gene and the flanking regions in DNA samples of family members. We observed no features typical of renal osteodystrophy or rickets, with the exception of short stature, in the three afffected male family members. Audiometry, visual acuity and olfactory sensation were normal. By performing PCR analysis of the steroid sulfatase (STS) gene and flanking regions on our patients, we discovered a complete deletion that involved the entire region from DXS1139 to DXF22S1. Further studies are required to determine whether the STS gene or the co-deleted flanking sequences are the cause of renal disease associated with XLI.

Differences in Tissue Expression of HBV Markers in Children with HBV-Associated Glomerulonephritis

Abstract Background/Aims: Hepatitis B virus-associated glomerulonephritis (HBV-GN) is recognized as one of the major secondary nephropathies in HBV high-risk areas. To determine possible differences in the expression of HBV immune markers in tissues, we retrospectively examined HBV immune markers in the serum, renal tissues, and liver tissues in 132 HBV-GN children. Methods: All 132 patients had biopsy-proven HBV-GN including the presence of positive HBV antigens in the kidney. Serum-HBV immune markers were tested by an enzyme-linked immunosorbent assay. Renal and liver biopsies were done in 26 patients. All renal tissues were examined for HBV immune markers by immunofluorescence, and liver tissues were examined by immunohistochemistry. Results: Among the 132 patients, all showed varying degrees of kidney injury. Serum hepatitis B envelope antigen (HBeAg) was positive in 80 patients and negative in 52 patients. The positivity rate of Hepatitis B core antigen in renal tissue was statistically higher in serum HBeAg (−) than in serum HBeAg (+) patients (96.2% vs. 55.0%). Furthermore, there was no relationship between the presence of hepatitis B surface antigen and HBcAg in liver and renal tissue. Conclusion: HBV markers are not consistently present in serum, renal tissues, and liver tissues in children with HBV-GN.

Lupus glomerulonephritis in 788 Chinese children: a multi-centre clinical and histopathological analysis based on 549 renal biopsies

Abstract Background: System lupus erythematosus (SLE) is a severe multisystem autoimmune disease. Objective: To describe the clinical and pathological features, treatment, and renal outcome in children under 18 years with lupus nephritis (LN). Methods: The study was undertaken by a questionnaire completed in 26 Grade 3A hospitals’ paediatric renal units in China. The study comprised 788 children (619 girls, 169 boys) diagnosed with SLE by the American College of Rheumatology criteria (1997) during 2005–2010. Results of renal biopsies were classified according to the guidelines of The International Association of Nephrology and the Renal Pathology Society (2003). Guidelines by the Chinese Society of Paediatric Nephrology were applied for the diagnosis and treatment (for trial implementation) in 2010 to determine inclusion. The data included the prevalence of acute kidney injury (AKI), SLE disease activity index (SLEDAI), renal histopathology and the induction of therapy mode. Results: The mean (SD) age of onset of SLE was 10.9 (2.90) years (range 1–18) and at diagnosis was 11.3 (2.9) years. The mean (SD) SLEDAI score was 13.5 (5.53). The clinical classification was as follows: about 36 (4.6%) patients had isolated haematuria, 99 (12.6%) isolated proteinuria, 60 (7.6%) isolated haematuria and proteinuria, 157 (19.9%) acute glomerulonephritis, 392 (49.7%) nephrotic syndrome, 20 (2.5%) rapidly progressive glomerulonephritis, 15 (1.9%) chronic nephritis, 2 (0.3%) tubule-interstitial damage and 7 (0.9%) subclinical LN. A total of 549 children (69.7%) underwent renal biopsy. The most frequent renal histopathological findings of LN were Class IV, followed by Class II and Class V + IV. There were no significant differences between the age groups in either renal pathological types or prognosis. In 242 (30.7%) patients, LN was complicated by AKI. Those with AKI had an older mean (SD) age at onset than the non-AKI patients [11.5 (2.8) years vs 10.7 (2.9) years, respectively, p < 0.0001] and a higher SLEDAI score [14.3 (5.8) vs 13.1 (5.4), respectively, p = 0.003]. In the induction phase, cyclophosphamide (CTX) and mycophenolate mofetil (MMF) were equally effective in the patients with the same pathological type. Follow-up records were only available for 482 (61.2%) patients, with a mean (SD) follow-up time of 21.5 (18.4) months. Six of the 35 patients who deteriorated required dialysis and seven died. Conclusion: In LN, AKI is a risk factor for poor outcome. Owing to different times of onset and remission, the pathological types of LN cannot be estimated by clinical manifestation alone, and therefore renal biopsy should be undertaken in all LN children with AKI. In the induction phase, there was no significant difference in efficacy between CTX and MMF. Follow-up of children with LN in China needs to be improved.

Genetic mutational testing of Chinese children with familial hematuria with biopsy‑proven FSGS

Focal segmental glomerulosclerosis (FSGS) is a pathological lesion rather than a disease, with a diverse etiology. FSGS may result from genetic and non-genetic factors. FSGS is considered a podocyte disease due to the fact that in the majority of patients with proven-FSGS, the lesion results from defects in the podocyte structure or function. However, FSGS does not result exclusively from podocyte-associated genes, however also from other genes including collagen IV-associated genes. Patients who carry the collagen type IVA3 chain (COL4A3) or COL4A4 mutations usually exhibit Alport Syndrome (AS), thin basement membrane neuropathy or familial hematuria (FH). Previous studies revealed that long-time persistent microscopic hematuria may lead to FSGS. A case of a family is presented here where affected individuals exhibited FH with FSGS-proven, or chronic kidney disease. Renal biopsies were unhelpful and failed to demonstrate glomerular or basement membrane defects consistent with an inherited glomerulopathy, and therefore a possible underlying genetic cause for a unifying diagnosis was pursued. Genomic DNA of the siblings affected by FH with biopsy-proven FSGS was analyzed, and their father was screened for 18 gene mutations associated with FSGS [nephrin, podocin, CD2 associated protein, phospholipase C ε, actinin α 4, transient receptor potential cation channel subfamily C member 6, inverted formin, FH2 and WH2 domain containing, Wilms tumor 1, LIM homeobox transcription factor 1 β, laminin subunit β 2, laminin subunit β 3, galactosida α, integrin subunit β 4, scavenger receptor class B member 2, coenzyme Q2, decaprenyl diphosphate synthase subunit 2, mitochondrially encoded tRNA leucine 1 (UUA/G; TRNL1) and SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily a like 1] using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technology. Then whole exome sequencing (WES) was performed in the two probands to ascertain whether there were other known or unknown gene mutations that segregated with the disease. Using mass array technology, a TRNL1 missense homozygous mutation (m. 3290T>C) was identified in the probands diagnosed with FH and manifested as FSGS on biopsy. In addition, a COL4A4 missense mutation c. 4195A>T (p. M1399L) in heterozygous pattern was identified using WES. None of these variants were detected in their father. In the present study, a mutation in TRNL1 (m. 3290T>C) was identified, which was the first reported variant associated with FSGS. The COL4A4 (c. 4195A>T) may co-segregate with FSGS. Screening for COL4A mutations in familial FSGS patients is suggested in the present study. Genetic investigations of families with similar clinical phenotypes should be a priority for nephrologists. The combination of mass array technology and WES may improve the detection rate of genetic mutation with a high level of accuracy.