Mitsuyuki Nakata

Induction of Wnt5a -Expressing Mesenchymal Cells Adjacent to the Cloacal Plate Is an Essential Process for Its Proximodistal Elongation and Subsequent Anorectal Development

Anorectal malformations encompass a broad spectrum of congenital defects and are related to the development of the genital tubercle, including the cloacal plate and urorectal septum. To explore the cellular and molecular basis of anorectal malformations, we analyzed the pathogenetic process using two mouse models: Danforths short tail (Sd) and all-trans retinoic acid (ATRA)-treated mice. Embryologically, the cloacal plate may be divided into distal and proximal parts, with the distal part subdivided into ventral and dorsal parts. In the two mouse models, anorectal malformations occur due to improper development of the proximal part of the cloacal plate. At 10.5 days postcoitus (dpc), in Sd homozygotes, there was a lack of Shh expression only in the cloacal plate and the endoderm around the cloacal plate. In addition, Wnt5a was not expressed in the mesoderm adjacent to the cloacal plate in the two mouse models, and Axin2, which is regulated by Wnt signaling, was not expressed in the dorsal part of the cloacal plate at 12.5 dpc. Based on these results, we suggest that Wnt5a, which is downstream of Shh signaling, and Axin2 affect the development of the proximal part of the cloacal plate.

Role of pediatric endoscopic retrograde cholangiopancreatography in an era stressing less-invasive imaging modalities.

Background:The significance of pediatric endoscopic retrograde cholangiopancreatography (ERCP) according to age or disease variation is inconclusive. This study aimed to evaluate the usefulness of pediatric ERCP in diagnosing or treating small children with pancreaticobiliary disorders, including choledochal cyst (CC) and biliary atresia (BA). Methods:From 1980 to 2011, 235 ERCPs were performed in 220 pediatric patients (median age, 2 years) at our institution. Underlying pathology was CC in 92 patients (3 years), BA in 62 patients (55 days), and others in 66 patients. Success and complication rates, and ERCP findings were retrospectively analyzed. Results:The overall success rate was 96%. Rates for individual pathologies were 99% for CC, 92% for BA, and 96% for others. The success rate was 100% among children >3 years, but 92% when limited to infants. Post-ERCP hyperamylasemia and duodenal perforation occurred in 9% and 0.4% of cases, respectively. Regarding preoperative evaluation of the pancreaticobiliary system in CC, ERCP clearly delineated pancreaticobiliary maljunction (79%) and the pancreatic duct (94%), whereas it visualized the common bile duct and intrahepatic bile duct at relatively low rates (77% and 33%, respectively). ERCP successfully identified 16 cases (18%) with non-BA of 90 patients with suspected BA. Moreover, ERCP demonstrated only pancreatic duct in 70% of all BA. Conclusions:ERCP among children including infants with CC and BA can be performed with fairly satisfactory results. Although pediatric ERCP can also help describe the pancreaticobiliary system in detail, its indication should be deliberately considered when anatomical information from less-invasive imaging modalities is insufficient.

Endoscopic management for congenital esophageal stenosis: A systematic review

Congenital esophageal stenosis (CES) is an extremely rare malformation, and standard treatment have not been completely established. By years of clinical research, evidence has been accumulated. We conducted systematic review to assess outcomes of the treatment for CES, especially the role of endoscopic modalities. A total of 144 literatures were screened and reviewed. CES was categorized in fibromuscular thickening, tracheobronchial remnants (TBR) and membranous web, and the frequency was 54%, 30% and 16%, respectively. Therapeutic option includes surgery and dilatation, and surgery tends to be reserved for ineffective dilatation. An essential point is that dilatation for TBR type of CES has low success rate and high rate of perforation. TBR can be distinguished by using endoscopic ultrasonography (EUS). Overall success rate of dilatation for CES with or without case selection by using EUS was 90% and 29%, respectively. Overall rate of perforation with or without case selection was 7% and 24%, respectively. By case selection using EUS, high success rate with low rate of perforation could be achieved. In conclusion, endoscopic dilatation has been established as a primary therapy for CES except TBR type. Repetitive dilatation with gradual step-up might be one of safe ways to minimize the risk of perforation.

Use of preoperative, 3-dimensional magnetic resonance cholangiopancreatography in pediatric choledochal cysts

BACKGROUND Standard choledochal cyst (CC) operations involve dilated extrahepatic bile duct excision followed by biloenterostomy. However, biliary variants and associated intrahepatic bile duct (IHBD) stenoses or dilatations triggering postoperative sequelae require additional procedures. The usefulness of preoperative 3-dimensional magnetic resonance cholangiopancreatography (3D MRCP) and virtual cholangioscopy (VES) for observing biliary morphology and pancreaticobiliary maljunction (PBM) was evaluated. METHODS In 16 pediatric CC patients (age range, 4 months to 9 years; median, 3 years), visualization of PBM and aberrant bile duct anatomy and IHBD morphology at the hepatic hilum (HH), umbilical portion (UP), and posterior branch (POST) were compared between 3D-MRCP and intraoperative cholangiography (IOC). VES and intraoperative cholangioscopy (IOS) findings were compared. RESULTS HH, UP, and POST visualization rates were 100%, 94%, and 94%, respectively, by 3D-MRCP, and 100%, 69%, and 69%, respectively, by IOC. IHBD stenosis detection rates at each region were 38%, 13%, and 13%, respectively, by 3D-MRCP, and 25%, 0%, and 9%, respectively, by IOC. IHBD dilatation detection rates at each part were 75%, 47%, and 60%, respectively, by 3D-MRCP, and 88%, 82%, and 91%, respectively, by IOC. PBM was confirmed in 56% and 93% of cases on 3D-MRCP and IOC, respectively. Both 3D-MRCP and IOC showed biliary variants in 5 cases (31%). VES showed membranous strictures at HH, UP, and POST in 6, 2, and 2 cases, respectively, whereas IOS did so at HH in 4 cases and POST in 2. CONCLUSION Preoperative 3D-MRCP and VES accurately depict biliary morphology, allowing concrete operative planning in pediatric CC patients, complementing IOC and IOS.

Toll-like receptor mRNA expression in liver tissue from patients with biliary atresia.

Background and Aim: Inappropriate host immunological reactions against unknown ligands via the Toll-like receptor (TLR) cascades may trigger progressive inflammatory biliary destruction that manifests as biliary atresia (BA) in newborns or infants. The aim of the study was to clarify the role of the innate immune system in the development of BA. Patients and Methods: Liver tissue was obtained from 49 patients with pediatric hepatobiliary diseases: 19 with BA, 21 with choledochal cysts, and 9 with other hepatobiliary diseases. BA samples obtained during the initial portoenterostomy and reoperation or liver transplantation (LT) were classified as early and late BA groups, respectively. Of the early BA group, those requiring LT were designated as the LT group, and the others were designated as the non-LT group. The mRNA expression levels of TLRs 2, 3, 4, 7, and 8 were determined by real-time quantitative reverse transcription-polymerase chain reaction and were compared between groups. The correlation between TLR mRNA expression level and age at sampling was examined for each TLR in the patients with BA. Results: TLR8 mRNA, encoding the receptor for single-stranded RNA, was significantly higher in the early BA group, compared with non-BA groups (P = 0.008). Within the BA group, mRNA levels of TLRs 2 and 8 were significantly higher in the early group than in the late group (P = 0.02 and 0.006, respectively), despite there being no significant correlation between TLR mRNA expression and age at sampling, except for TLR7 (r = 0.77, P = 0.001). Compared with the non-LT group, the LT group demonstrated significantly higher mRNA expression of TLRs 3 and 7 (P = 0.02 and 0.01, respectively). Conclusions: Innate immune responses may contribute to the initiation and progression of BA. Severe inflammation characteristic of BA around the time of the first operation may abate postoperatively, but determination of selected TLR mRNA expression levels in the liver at the time of Kasai portoenterostomy may assist in predicting the prognosis of patients with BA.

A rare presentation in a case of gastric duplication cyst communicating to the pancreatic duct: coincidental detection during pyloromyotomy for hypertrophic pyloric stenosis

A rare case of gastric duplication of childhood is reported. A 1-month-old boy underwent pyloromyotomy for infantile hypertrophic pyloric stenosis. At laparotomy, a protruding lesion was identified in the anterior wall of the pylorus. The pylorus was hypertrophic as indicated preoperatively, and a normal pyloromyotomy was performed. Wedge biopsy of the protruding lesion revealed an intestinal structure, and gastric duplication was diagnosed. The child remained asymptomatic thereafter, but considering the risk of the duplication becoming symptomatic, a second laparotomy was performed at 1 year of age. The duplication cyst shared part of the wall with the pylorus, and the cyst was removed by cystectomy, leaving the pyloric muscle intact. The cyst was found to be communicating with the pancreatic duct. The child is doing well without any symptoms as of 18 months after second laparotomy. To the best of our knowledge, this is the youngest case of gastroduodenal duplication with pancreatic duct communication yet reported.

Antibody-dependent cellular cytotoxicity toward neuroblastoma enhanced by activated invariant natural killer T cells

Anti‐ganglioside GD2 antibodies mainly work through antibody‐dependent cellular cytotoxicity (ADCC) and have demonstrated clinical benefit for children with neuroblastoma. However, high‐risk neuroblastoma still has a high recurrence rate. For further improvement in patient outcomes, ways to maximize the cytotoxic effects of anti‐GD2 therapies with minimal toxicity are required. Activated invariant natural killer T (iNKT) cells enhance both innate and type I acquired anti‐tumor immunity by producing several kinds of cytokines. In this report, we investigated the feasibility of combination therapy using iNKT cells and an anti‐GD2 antibody. Although some of the expanded iNKT cells expressed natural killer (NK) cell markers, including FcγR, iNKT cells were not directly associated with ADCC. When co‐cultured with activated iNKT cells, granzyme A, granzyme B and interferon gamma (IFNγ) production from NK cells were upregulated, and the cytotoxicity of NK cells treated with anti‐GD2 antibodies was increased. Not only cytokines produced by activated iNKT cells, but also NK‐NKT cell contact or NK cell‐dendritic cell contact contributed to the increase in NK cell cytotoxicity and further IFNγ production by iNKT cells and NK cells. In conclusion, iNKT cell‐based immunotherapy could be an appropriate candidate for anti‐GD2 antibody therapy for neuroblastoma.

Significance of imaging modalities for preoperative evaluation of the pancreaticobiliary system in surgery for pediatric choledochal cyst

Roles of magnetic resonance cholangiopancreatography (MRCP), endoscopic retrograde cholangiopancreatography (ERCP), drip infusion cholangiography with computed tomography (DIC‐CT), and intraoperative cholangiopancreatography (IOCP) in visualizing pancreaticobiliary anatomy for pediatric choledocal cyst (CC) operations were examined.

Diagnosis of biliary atresia can not be excluded by declining trend of serum direct bilirubin

The aim of this paper is to investigate the clinical courses of patients with biliary atresia (BA) during neonatal period. We examined 19 patients with BA, who underwent blood tests including direct bilirubin (D-Bil) within 20 days of age, in 3 tertiary hospitals in Japan. The first blood sample was collected at 8.4±6.5 days of age. The acholic stool was observed within 2 weeks of age in 16 cases (84.2%). Decrease of T-Bil was observed in all the subjects, with a range of reduction of 6.5±3.3 mg/dL, from 10.4±7.5 to 29.8±9.1 days of age. Decrease of D-Bil was also observed in 17 out of 19 cases (89%), with a range of reduction of 1.1±1.0 mg/dL, from 15.5±8.0 to 24.9±9.6 days of age. A significant decrease of D-Bil was observed in 2 cases of biliary atresia splenic malformation syndrome. We therefore conclude that clinicians treating icteric infants should not exclude a diagnosis of BA even if the level of D-Bil has a declining tendency.

Malignant rhabdoid tumor of the liver: a case report and literature review

Malignant rhabdoid tumor (MRT) is a rare and aggressive malignancy associated with poor outcomes. MRT of the liver is even rarer, and little information has been described. We report the case of an 8-month-old boy with MRT of the liver. The tumor showed aggressive progression despite a multidisciplinary approach, and the patient died due to multiple organ failure 14 days after admission. Autopsy revealed the liver tumor and multiple metastases with negative immunohistochemistry for INI1/BAF47. A review of 53 cases of pediatric MRT of the liver is provided.