Weiwei Jiang

SLIT2/ROBO1-miR-218-1-RET/PLAG1: a new disease pathway involved in Hirschsprung's disease

Hirschsprungs disease (HSCR) is a rare congenital disease caused by impaired proliferation and migration of neural crest cells. We investigated changes in expression of microRNAs (miRNAs) and the genes they regulate in tissues of patients with HSCR. Quantitative real‐time PCR and immunoblot analyses were used to measure levels of miRNA, mRNAs, and proteins in colon tissues from 69 patients with HSCR and 49 individuals without HSCR (controls). Direct interactions between miRNAs and specific mRNAs were indentified in vitro, while the function role of miR‐218‐1 was investigated by using miR‐218 transgenic mice. An increased level of miR‐218‐1 correlated with increased levels of SLIT2 and decreased levels of RET and PLAG1 mRNA and protein. The reductions in RET and PLAG1 by miR‐218‐1 reduced proliferation and migration of SH‐SY5Y cells. Overexpression of the secreted form of SLIT2 inhibited cell migration via binding to its receptor ROBO1. Bowel tissues from miR‐218‐1 transgenic mice had nerve fibre hyperplasia and reduced numbers of gangliocytes, compared with wild‐type mice. Altered miR‐218‐1 regulation of SLIT2, RET and PLAG1 might be involved in the pathogenesis of HSCR.

Inhibition of Toll-like receptor 4 with vasoactive intestinal peptide attenuates liver ischemia-reperfusion injury.

BACKGROUND Toll-like receptor 4 (TLR4) has attracted a great deal of attention in ischemia-reperfusion (IR) injury in recent years. Vasoactive intestinal peptide (VIP) plays an important role in anti-inflammatory and immunomodulatory activity in several animal models. There are no data available regarding the effect of VIP on TLR4 expression in IR injury in vivo. In the present study, we study the effect of VIP on TLR4 expression in mouse macrophage cell line RAW 264.7 and a mouse partial IR model. METHODS The potential inhibitory effect of VIP on TLR4 mRNA and protein in a mouse macrophage cell line and in a mouse model of partial warm hepatic IR injury was assessed. We also assessed the expression tumor necrosis factor (TNF)-α and interleukin (IL)-6 in this model. RESULTS Expression of TLR4 mRNA levels was significantly decreased at 6, 12, and 24 hours after treat with VIP in mouse macrophage cell line RAW 264.7. Expression of TLR4 mRNA, TLR4 protein, alanine aminotransferase, TNF-α, and IL-6 levels were significantly increased in the IR group but significantly decreased in groups pretreated with VIP at a concentration of 5 and 10 nmol. Hematoxylin and eosin staining show apparent edema and necrosis were observed in the IR group, but in the VIP pretreatment group, edema and necrosis in IR modes were reduced. CONCLUSION This study showed that VIP might inhibit TLR4 in vitro and in vivo, and pretreatment with VIP might inhibited TLR4 activation and reduced warm IR injury.

Down-Regulation of MicroRNA-146a in the Early Stage of Liver Ischemia-Reperfusion Injury

BACKGROUND MicroRNAs (miRNAs), 21-23-nucleotide noncoding RNAs, act as regulators of gene expression transcriptionally. MicroRNA-146a(miR-146a) has been demonstrated to be one of the key molecules in oncogenesis and inflammatory responses. Few data describe the expression of miR-146a in liver ischemia-reperfusion (IR) injury. The present study sought to explore the relationship of miR-146a to Toll-like receptor 4 (TLR4) signaling pathways in a rat model of warm IR injury. METHODS The expression of miR-146a was detected by real-time reverse-transcriptase polymerase chain reaction using a partial warm hepatic IR injury model. The expression of TLR4, tumor necrosis factor receptor-associated factor 6 (TRAF6), and interleukin-1 receptor-associated kinase (IRAK 1) protein was assessed by Western blotting as well as the signaling pathways induced by TLR4. RESULTS The expression of hepatic miR-146a was down-regulated in IR injury during the 24 hours after reperfusion, reaching the lowest level at 6 hours after reperfusion. Increases in TLR4, TRAF6, and IRAK1 were accompanied by decreased miR-146a during the 24 hours after reperfusion, peaking at 6 hours. Immunohistochemistry showed cytoplasmic expression of cells positive for TLR4, and nuclear expression of cells positive for nuclear factor κB p65 and c-jun to be increased among IR groups after reperfusion. CONCLUSION miR-146a was down-regulated in the early stage of liver IR injury.

Use of small intestinal submucosal and acellular dermal matrix grafts in giant omphaloceles in neonates and a rabbit abdominal wall defect model.

BACKGROUND The described surgical strategies for the management of omphalocele include primary closure, staged closure, and delayed closure. A primary repair is not suitable for all giant omphaloceles. We implanted two grafts, small intestinal submucosal (SIS) and acellular dermal matrix (ADM) onto abdominal wall defects in neonates to study the safety and efficacy of SIS and ADM graft techniques for initial closure of giant omphaloceles in infants, and we also implanted these grafts onto abdominal wall defects in an animal model. METHODS Twenty-four patients with giant omphaloceles were divided into two groups (ADM group, 12 patients; SIS group, 12 patients). The operative time, skin healing time postoperatively, and the incidence of skin infections, and abdominal wall hernias were observed. In the rabbit animal model, bilateral full-thickness incisions were made through the rabbit rectus abdominus muscles and a 2×4cm longitudinal whole layer defect was created on either the left or right lateral anterior abdominal wall. A four-layered variant of the SIS graft was used to repair the right abdominal defect; ADM was used to repair the left. Tensile strength was measured using an Instron tensiometer. Electron scanning and light microscopy were used to evaluate neovascularization, collagen deposition, and muscle fibers at 2, 4, 8, and 16weeks postimplantation. RESULTS In the neonatal patients, there was no statistically significant difference between the two groups with respect to operative time, skin healing time postoperatively, the incidence of skin infections, or abdominal wall hernias. In the SIS group, only one patient developed a skin infection, which led to skin necrosis and sloughing. In the ADM group, four patients developed skin infection postoperatively, and the patch was gradually removed. In the animal study, there was no significant difference between the mean breaking strength of ADM versus SIS repairs. Scanning electron and light microscopy showed collagen deposition, increased vascularization, fibroblasts, and muscular regeneration in both SIS and ADM repairs. SEM showed that the SIS graft was absorbed, while ADM was not. Light microscopy showed foreign body macrophages in ADM, but not in the SIS repairs. CONCLUSION SIS and ADM grafts adequately enhance healing with a low complication rate. Compared with ADM grafts, SIS is absorbable, induces less inflammation, and is more biocompatible, and therefore might be more useful and suitable for closure of abdominal wall defects.

Aberrant high expression of NRG1 gene in Hirschsprung disease.

BACKGROUND/PURPOSE Hirschsprung disease (HSCR) is a congenital disorder characterized by the absence of intramural ganglion cells along with variable lengths of the gastrointestinal tract. Recent studies have indicated the potential function of neuregulin-1 (NRG1) in HSCR, which encodes the heregulins and other mitogenic ligands for the ErbB family. The purpose of this study was to further clarify the role of NRG1 in the pathogenesis of HSCR. METHODS We examined the NRG1 messenger RNA (messenger RNA) and protein expression levels in gut tissues of 63 patients with sporadic HSCR (both stenotic and dilated gut tissues) and 35 controls. Moreover, using the methylation-specific polymerase chain reaction, we examined the methylation pattern of exon 1 of the NRG1 gene. RESULTS The mRNA expression levels of NRG1 were significantly higher in tissues of HSCR than those in controls, and the increased NRG1 protein levels in HSCR were consistent with the mRNA levels. However, no methylation pattern change was observed in exon 1 of the gene among different groups. CONCLUSIONS Our study demonstrates that the aberrant expression of NRG1 may play an important role in the pathology of HSCR. DNA methylation of the gene seems not to be involved in the mechanism of such aberrant expression, and other factors should be explored.

Enteroenteroanastomosis near adjacent ileocecal valve in infants

AIM To investigate the feasibility and the effectiveness of ileoileostomy in the region adjacent to the ileocecal valve, which can retain the ileocecal valve in infants. METHODS This is a retrospective review of 48 patients who underwent ileoileostomy in the region adjacent to the ileocecal valve (group 1) and 34 patients who underwent ileocecal resections and ileotransversanastomosis (group 2). Patients were monitored for the time to flatus, resumption of eating, length of hospital stay after surgery, serum total bile acid, vitamin B12 and postoperative complications. RESULTS The time to flatus, time until resumption of eating and post-operative length of hospital stay showed no statistically significant differences between the two groups. Serum total bile acid and vitamin B12 were not significantly different between the two groups at post-operative day 1 and day 3, but were significantly decreased at 1 wk after operation in group 2. None of the patients died or suffered from stomal leak in these two groups. However, the incidence of diarrhea, intestinal infection, disturbance of acid-base balance and water-electrolytes in group 1 was lower than in group 2. CONCLUSION Ileoileostomy in the region adjacent to the ileocecal valve is safe and results in fewer complications than ileotransversanastomosis in infants.

Mutations of MYH14 are associated to anorectal malformations with recto-perineal fistulas in a small subset of Chinese population

Background: Anorectal malformations (ARMs) are among the most commonly congenital abnormalities of distal hindgut development, ranging from anal stenosis to anal atresia with or without fistulas and persistent cloaca. The etiology remains elusive for most ARM cases and the majority of genetic studies on ARMs were based on a candidate gene approach.

Postoperative intussusception in infants and children: a report of seven cases

Postoperative intussusception is an uncommon but serious condition in infants and children. Here, we report seven cases of postoperative intussusception in infants and children who were seen at our institution over the last 13 y. The patients showed increased nasogastric drainage, vomiting, lack of stool, and/or growing abdominal distension 2 to 9 d following abdominal surgery. Manual reduction was successful in five cases. In two cases, necrosis was found and intestinal resection and anastomosis were carried out. No recurrence was observed at six months of follow-up. Postoperative intussusception should be suspected in pediatric surgical patients who showed signs of intestinal obstruction in the early postoperative period.

Early Enteral Nutrition in Neonates with Partial Gastrectomy-A Multi-center Study

BACKGROUND AND OBJECTIVES Compared with total parenteral nutrition (TPN), enteral nutrition is more suitable for patients post-operatively. Our aim was to determine the safety and feasibility of early enteral nutrition (EEN) using a jejunum feeding tube in neonates after undergoing a partial gastrectomy. METHODS AND STUDY DESIGN This was a retrospective review of 46 patients who underwent partial gastrectomies for gastric perforation in our hospital. These patients were categorized into two groups (EEN group [n=24 patients], a jejunal feeding tube was inserted during surgery; and a control group [n=22 patients], a jejunal feeding tube was not placed). Differences in operative time, time to first defecation post-operatively, time to first oral feeding post-operatively, length of hospital stay post-operatively, nutrition indices, and post-operative complications (died due to septic shock, cholestasis, pneumonia, abdominal distension, and diarrhea) were reviewed. RESULTS There were no significant differences in the operative time and the time to first oral feeding post-operatively between the two groups; however, the time to first defecation post-operatively in the EEN group and the hospital length of stay post-operatively for the EEN group were significantly shorter than the control group. The levels of albumin, retinol binding protein, and prealbumin were not significantly different between the two groups pre-operatively and 14 days postoperatively. The incidence of cholestasis and abdominal distention in the EEN group was significantly lower than the control group. CONCLUSION EEN using a jejunal feeding tube in neonates who have undergone a partial gastrectomy for gastric perforation is safe, easy, and has fewer complications than TPN.

Lipopolysaccharide enhances ADAR2 which drives Hirschsprung's disease by impairing miR-142-3p biogenesis

Researches over the past decade suggest that lipopolysaccharide is a dominant driver of gastrointestinal motility and could damage the enteric neuron of rat or porcine. However, it remains poorly defined whether LPS participates in Hirschsprungs disease (HSCR). Here, we discovered that LPS increased in HSCR tissues. Furthermore, LPS treatment suppressed the proliferation and differentiation of neural precursor cells (NPCs) or proliferation and migration of human 293T cells. ADAR2 (adenosine deaminase acting on RNA2)‐mediated post‐transcriptional adenosine‐to‐inosine RNA editing promotes cancer progression. We show that increased LPS activates ADAR2 and subsequently regulates the A‐to‐I RNA editing which suppresses the miR‐142 expression. RNA sequencing combined with qRT‐PCR suggested that ADAR2 restrain cell migration and proliferation via pri‐miR‐142 editing and STAU1 up‐regulation. In conclusion, the findings illustrate that LPS participates in HSCR through the LPS‐ADAR2‐miR‐142‐STAU1 axis.