Zhuwen Yi

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.

Effect of Stem Cell Factor and Granulocyte-Macrophage Colony-Stimulating Factor-Induced Bone Marrow Stem Cell Mobilization on Recovery from Acute Tubular Necrosis in Rats

Background: Acute tubular necrosis (ATN) is the most common reason for acute kidney injury (AKI), and there is still an absence of effective therapies. Objective: To assess the value of bone marrow cell mobilization by stem cell factor (SCF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) therapy in rats with gentamicin-induced ATN. Methods: ATN was induced in male Sprague–Dawley (SD) rats with five daily high-dose intraperitoneal injections of gentamicin. Subcutaneous injections of SCF and GM-CSF were administered simultaneously and these cytokines were observed on days 2, 5, 10, 17, 24, and 31. Peripheral blood and renal tissue CD34+ cell count, mortality rate, blood urea nitrogen (BUN), serum creatinine (SCr), creatinine clearance rate (CCr), and histopathologic lesion scores were determined. Twelve hours after bone marrow ablation (BMA) by lethal X-ray radiation, specific pathogen-free (SPF) ATN rats were given five daily injections of SCF and GM-CSF. BUN, SCr, and histopathologic lesion scores were evaluated on days 2, 5, and 10. Results: Peripheral blood CD34+ cell count increased significantly in ATN rats between 2 and 10 days after SCF and GM-CSF injection. Mortality was reduced from 34.7% in the ATN group to 18.6% in the ATN+CSF. In addition, cytokines administration significantly decreased SCr and BUN. Moreover, cytokines rapidly ameliorated tubular injury. There was no significant effect on ATN rats after BMA. Conclusions: This study demonstrated that SCF and GM-CSF effectively mobilized bone marrow cells in ATN rats, and cytokines administration partially prevented gentamicin-induced ATN. These results suggest that bone marrow stem cell (BMSC) mobilization may be an effective therapy for ATN.

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.

Environmental factors for the development of fetal urinary malformations.

BackgroundThe development of the kidneys and other organs of the urinary tract also follow the natural rule of gene-environment-lifestyle interaction. Both intrinsic and extrinsic factors may be associated with the etiology of various kinds of urinary malformations. The environmental factors belong to extrinsic factors, which have attracted increasing attention from researchers.MethodsPublications about urinary malformations were searched from databases such as PubMed, Elsevier, Chemical Abstract, Excerpta Medica, Chinese Hospital Knowledge Database and Wanfang Database.ResultsUrinary malformation is associated with low birth weight, maternal diseases, placental insufficiency, maternal drug exposure, and maternal exposure to environmental pesticides. Living environment and socioeconomic factors may also influence the incidence of urinary malformation.ConclusionIt is important to understand the association of environmental factors with the development of the renal system and urinary malformation in order to decrease the incidence of urinary malformations.

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.

HOXA13 exerts a beneficial effect in albumin-induced epithelial-mesenchymal transition via the glucocorticoid receptor signaling pathway in human renal tubular epithelial cells

Previous studies have suggested that albumin-induced renal tubular epithelial cell injury contributes to renal interstitial fibrosis. Epithelial-mesenchymal transition (EMT) is known to be a key mechanism in the pathogenesis and progression of renal interstitial fibrosis. Homeobox protein HOX‑A13 (HOXA13) is a nuclear transcriptional factor that has been reported to be involved in renal fibrosis. However, the mechanism underlying the effect of HOXA13 in human serum albumin (HSA)‑induced EMT in HKC renal tubular epithelial cells remains to be elucidated. Thus, the aim of the present study was to investigate the role of HOXA13 in HSA‑induced EMT in HKC cells and the potential mechanism of the glucocorticoid receptor (GR) signaling pathway. The protein and mRNA expression levels of HOXA13, cytokeratin, and vimentin were determined by western blot analysis and reverse transcription‑quantitative polymerase chain reaction in HKC cells, which were co‑incubated with HSA at different concentrations or for different time periods. The results demonstrated that HOXA13 mRNA and protein expression decreased in a dose‑ and time‑dependent manner when induced by HSA in HCK cells. The liposomal transfection experiment suggested that overexpression of HOXA13 activated the GR signal, which inhibits HSA-induced EMT. HOXA13 is involved in HSA‑induced EMT in HKC cells and upregulation of HOXA13 exerts a beneficial effect in EMT, which may be associated with the GR signaling pathway.

Efficacy of antisense monocyte chemoattractant protein-1 (MCP-1) in a rat model of mesangial proliferative glomerulonephritis.

Abstract Objective: The effects of inhibition of monocyte chemoattractant protein-1 (MCP-1) on a rat model of mesangial proliferative glomerulonephritis (MsPGN) were evaluated. Methods: The anti-Thy-1 MsPGN model was developed by intravenously injecting anti-Thy-1 monoclonal antibodies into rats, followed by an injection of mesangial cells transfected with antisense MCP-1 into the renal artery. Exogenous cells were detected by in situ hybridization. Rats (40 total) were randomly divided into five groups: SO (sham operation), TG (Thy-1 glomerulonephritis model), MC (non-transfected normal rat mesangial cell), BC (pLXSN empty vector or blank control), and AM (antisense MCP-1 transfection) groups. Effects of exogenous MCP-1 on urinary protein excretion rate, biochemical parameters, and pathological changes were evaluated. Expression of MCP-1 and transforming growth factor-β1 (TGF-β1) were detected by immunohistochemistry. mRNA expression of MCP-1, TGF-β1, and CC chemokine receptor 2 (CCR2) were detected by RT-PCR. Results: Exogenous MCP-1 cDNA was successfully transfected into mesangial cells. Exogenous mesangial cells were detected in glomeruli by in situ hybridization. Glomerular mesangial cell proliferation, 24-h urinary protein excretion rate, mRNA expression of MCP-1, TGF-β1, and CCR2, and protein expression of MCP-1 all decreased in the AM group as compared to the control group (p < 0.05), but there was no significant difference in the expression level of TGF-β1 protein. Conclusions: (1) Mesangial cells can be used as a vector to transfect exogenous genes into kidneys; (2) antisense MCP-1 decreases mesangial cell proliferation and pathological injury in MsPGN model rats by decreasing expression of MCP-1 and CCR2; and (3) antisense MCP-1 suppressed mesangial cell proliferation and matrix accumulation in anti-Thy-1 MsPGN model rats, which did not entirely depend on TGF-β1.

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.