Xiaochuan Wu

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.

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.

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.

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.

Predictability of Urinary CD80 in the Relapse of Primary Nephrotic Syndrome

Purpose The current study is aimed at investigating whether urinary CD80 is reliable to predict the recurrence of pediatric PNS. Materials and Methods A total of 128 children, 105 males and 23 females, were enrolled in this study. Urinary samples were collected from SSNS and SRNS patients and 25 healthy children as controls. Urinary CD80 was measured by ELISA and adjusted for urinary creatinine excretion. Results Urinary CD80 in relapse stage of SSNS was significantly higher, and the urinary CD80 of paired relapse and remission stages of each SSNS patient were also significantly different. No significant difference was found between the urinary CD80 in SRNS relapse group, SRNS remission group, and the control group. Similarly, there was no significant difference between frequent SSNS and not frequent SSNS in remission group, as well as the relapse group. There is no correlation between urinary CD80 and 24-hour urinary protein. Conclusion The increase of urinary CD80 was closely associated with the relapse of SSNS but was not related to the frequency of relapse. The urinary CD80 changes of concentration were reliable to predict the recurrence of SSNS. However, it cannot be used to predicate the frequent recurrence of PNS.

Distribution of infused umbilical cord mesenchymal stem cells in a rat model of renal interstitial fibrosis

Abstract Aims: Stem cell transplantation for the treatment of kidney diseases is dependent on choice of transplant pathway. We evaluated the safety of human umbilical cord mesenchymal stem cells through peripheral infusion and their distribution in a rat model of renal interstitial fibrosis (RIF). Method: Cryopreserved umbilical cord mesenchymal stem cells were infused via tail vein injection into rats with unilateral ureteral obstruction and Sham-operated. Blood, kidney, heart, liver, spleen and lung were collected at 14, 21, and 28 days after infusion. Testing included microscopic observation of kidney morphological changes and immunohistochemical testing to identify and count the number of MAB1281 (labeled human cells) positive cells in the heart, liver, spleen, lungs, and kidneys of different treatment groups. Results: There was no significant difference in the Sham-operated group and Sham-operated + cell transplantation group at different time points. Human cells were identified mainly in the lungs, spleen, and kidney. The number of human umbilical cord mesenchymal stem cells in the kidney was greater in the unilateral ureteral obstruction + cell transplantation group, compared to the Sham-operated + cell transplantation group. human umbilical cord mesenchymal stem cells were mainly located in the interstitium of the left kidney. These results suggest that infused mesenchymal stem cells were primed to engraft a damaged kidney, especially damaged renal interstitium. Conclusions: Intravenous infusion of exogenous umbilical cord mesenchymal stem cells is feasible and safe. Infused mesenchymal stem cells can reach damaged kidney tissues with obstructive RIF after a vein graft.

Podocalyxin expression in renal tissues and correlation with the number of urinary podocytes in children with Henoch-Schonlein purpura nephritis.

OBJECTIVE To analyze the podocalyxin (PCX) expression in the kidney and the number of urinary podocytes in different pathological grades of Henoch-Schonlein purpura nephritis (HSPN), and to determine whether the number of urinary podocytes reflects the renal damage in HSPN. METHODS Fifty-six children diagnosed with HSPN in our hospital were enrolled in the study and classified into 4 groups by renal pathology: grade II (IIa+IIb) (n=10), grade III (IIIa+IIIb) (n=21), grade IV (n=16), and grade V (n=9). Four kidney autopsy specimens without histomorphologic lesions and 8 urine samples from healthy children served as controls. With immunofluorescence assay, the PCX expression in 4 normal renal tissues and in the renal tissues of the 56 HSPN children was detected and quantitatively analyzed. Positive rate and the number of urinary podocytes were detected in the 8 healthy children and 56 HSPN children. RESULTS In the renal tissues of the normal control group and grade II (IIa+IIb) HSPN group, the PCX expression was complete. The percentage of the PCX positive area out of the total glomerular area in the renal tissues of 2 groups had no significant difference (P>0.05). In the renal tissues of grade III (IIIa+IIIb), IV, and V HSPN groups, the PCX expression showed various degrees of loss, decreasing in turn from grade II (IIa+IIb), III (IIIa+IIIb), IV to V, with significant differences between each group (P<0.01). For HSPN with grade III (IIIa+IIIb) or higher, positive PCX expression was found in the urine, suggesting the presence of enough podocytes in the urine. The percentage of fluorescence positive area out of the total glomerular area of PCX in the renal tissues was negatively correlated with the total number of urinary podocytes (r=-0.637, P<0.01). CONCLUSION Podocyte injury plays a certain role in the pathological progression of HSPN. The urinary detection of podocytes can reflect the degrees of pathological damage in HSPN.

Sympathetic nervous system level and ambulatory blood pressure in children with primary nephrotic syndrome

OBJECTIVE To explore the change in ambulatory blood pressure monitoring (ABPM) value and the sympathetic nervous system (SNS) level in children with primary nephrotic syndrome(PNS) and their relationship. METHODS ABPM and casual blood pressure(CBP) were tested in 114 children with PNS and 12 normal children as a control group. The 24-h urine noradrenaline(NA), adrenaline(A) and dopamine(DA) content were detected through high-performance liquid chromatography with electrochemical luminescence and the correlation with ABP was analyzed. RESULTS Among 114 children with PNS, 101 had elevated blood pressure (88.6%), 45 showed high incidence of masked hypertension (39.5%), and 80 non-dipper blood pressure (70.2%). Systolic blood pressure level and blood pressure load were greater than diastolic blood pressure. NA, A, and DA levels of the PNS group were significantly higher than those of the control group, while those of the elevated blood pressure group were significantly higher than those of the normal blood pressure group in PNS children. SNS levels were positively correlated with blood pressure levels and blood pressure load, and negatively correlated with night BP decreasing rates. CONCLUSION Children with PNS have high incidence of hypertension with large proportion of masked hypertension and non-dipper blood pressure. Severe masked hypertension classification should be set up. In PNS children, SNS activity is elevated that might evaluate the blood pressure level and decrease blood pressure circadian rhythm.