A novel mouse model of intestinal neuronal dysplasia: visualization of the enteric nervous system.

PURPOSE: Intestinal neuronal dysplasia (IND) is a congenital anomaly affecting gastrointestinal neural innervation, but the pathogenesis remains unclear. The homozygous Ncx/Hox11L.1 knockout (Ncx-/-) mice exhibit megacolon and enteric ganglia anomalies, resembling IND phenotypes. Sox10-Venus transgenic mouse were used to visualize enteric neural crest cells in real time. This study aims to establish a novel mouse model of Sox10-Venus+/Ncx-/- mouse to study the pathogenesis of IND. METHODS: Sox10-Venus+/Ncx-/- (Ncx-/-) (n = 8) mice and Sox10-Venus+/Ncx+/+ controls (control) (n = 8) were euthanized at 4-5 weeks old, and excised intestines were examined with fluorescence microscopy. Immunohistochemistry was performed on tissue sections with neural marker Tuj1. RESULTS: Ncx-/- mice exhibited dilated cecum and small intestine. Body weight of Ncx-/- mice was lower with higher ratio of small intestine length relative to body weight. The neural network (Sox10-Venus) was observed along the intestine wall in Ncx-/- and control mice without staining. Ectopic and increased expression of Tuj1 was observed in both small intestine and proximal colon of Ncx-/- mice. CONCLUSION: This study has established a reliable animal model that exhibits characteristics similar to patients with IND. This novel mouse model can allow the easy visualization of ENS in a time- and cost-effective way to study the pathogenesis of IND.

The impact of the recipient intestinal site on the differentiation of transplanted enteric neural crest cells.

PURPOSE: It has long been established that the failure of enteric neural crest cells (ENCCs) to colonize the entire gut results in aganglionosis at the distal colon in Hirschsprung disease (HD). However, it is still unclear how the intestinal microenvironment of the distal aganglionic gut differs from that of the proximal ganglionic gut in HD versus normal gut. We have recently succeeded in transplanting ENCC into aganglionic gut in endothelin receptor B (Ednrb) knockout (KO) mice. to advance the development of cell therapy for HD, it is essential to determine if the transplanted ENCCs differentiate normally in aganglionic gut. Therefore, we designed this study to investigate the impact of the environment of the recipient intestinal tract, at various sites of aganglionic gut, on the differentiation of transplanted ENCCs. METHODS: ENCCs were isolated from Sox10 Venus transgenic (Tg) mouse gut on embryonic day 18.5 (E18.5) and neurospheres (NS) were generated. Then, NS were transplanted into aganglionic KO and wildtype (WT) gut that had been transected just distal to the ENCC wavefront (KO-wf: n = 6, WT: n = 7), and into distal KO gut transected at a site equivalent to that of the WT (KO-d: n = 6) on E12.5. ENCC differentiation was evaluated using whole-mount immunohistochemistry with Tuj-1 (neuronal marker) and GFAP (glial marker) antibodies. RESULTS: The transplanted ENCCs migrated to form the myenteric and submucosal plexus in all groups. The ratio of the area of Tuj-1-positive cells/GFAP-positive cells in migrated cells in the recipient gut was found to be significantly lower in KO-d compared to KO-wf and WT, while there was no significant difference between KO-wf and WT groups. This suggests that neuronal/glial differentiation was decreased in KO-d compared to that in KO-wf and WT groups. CONCLUSION: Our study highlights the differences in ENCC differentiation depending on the site of transplantation. To further develop cell therapy for HD, it is important to consider the impact of the recipient intestinal environment on transplanted ENCCs.

Assessment of laparoscopic inguinal hernia repair using the classification for single port laparoscopy in adolescents and young adults.

BACKGROUND: Inguinal hernia repair is one of the most common operations performed worldwide. No consensus currently exists regarding the most appropriate operation for inguinal hernia in adolescent and young adult (AYA) patients. This study aimed to evaluate the outcomes in AYA patients undergoing high ligation or mesh repair under laparoscopy by examining the location and size of the hernia orifice defect. METHODS: We retrospectively reviewed all patients aged 15 to 40 years old who underwent laparoscopic hernia repair. Under single port laparoscopy, we classified the anatomic location (lateral, medial, or femoral) and size of the hernia orifice according to the classification by the European Hernia Society (EHS). A laparoscopic percutaneous extraperitoneal closure (LPEC) was performed on the patients with a lateral hernia with a hernia orifice defect size of ≤1.5 cm (L1). Transabdominal preperitoneal (TAPP) repair was performed on the patients with a lateral hernia with a hernia orifice defect size of >1.5 cm (L2 or 3). RESULTS: Overall, 40 patients underwent the mentioned surgical procedures. We performed LPEC on 22 patients, and TAPP on 18 patients. There were no intraoperative or postoperative complications and recurrences. CONCLUSIONS: This is the first report that evaluated the outcomes of AYA patients who underwent high ligation or mesh repair under laparoscopy by examining the location and size of the hernia orifice defect. Our data indicated that LPEC were effective and safe for AYA patients with small hernia orifice defect.

Japan's comprehensive undescended testis screening program: incidence of ascending testis after screening.

PURPOSE: Screening for undescended testis (UDT) in Japan is performed as a neonate, then at 1, 3, 10, and 18 months old, and 3 years old. Incidence of ascending testis (AT) after screening was reviewed. METHODS: All orchiopexy/orchiectomy at a single institute between July 2005 and June 2022 were reviewed retrospectively. RESULTS: 376 boys had 422 procedures; 54/422 (12.8%) were in 48 boys ≥ 4 years old (mean age: 6.7 years; range: 4-13); testes were normal (n = 22; 40.7%), small (n = 25; 46.2%), or atrophied (n = 7; 1.3%). There were 47 orchiopexies and 7 orchiectomies for atrophy. Incidence of AT in boys ≥ 4 years old was 24/422 (5.7%). Of these, 16/422 (3.8%) developed after normal descent and 8/422 (1.9%) were associated with retractile testis (AT + RET). Other indications included delayed treatment for UDT (n = 13), late referral by pediatricians (n = 10), and iatrogenic UDT (n = 6). Surgical intervention in boys ≥ 4 years old (12.8%) was less than that reported in the West (range: 30-50%) as was AT: (5.7% versus 15.4%) and AT + RET (1.9% versus 13.8%). CONCLUSIONS: Comprehensive UDT screening probably contributed to the lower incidence of surgery and AT (especially AT + RET) in boys ≥ 4 years old.

Increased enteric neural crest cell differentiation after transplantation into aganglionic mouse gut.

PURPOSE: In recent years, many studies have made considerable progress in the development of stem cell-based therapies for Hirschsprung's disease (HD). However, the question of whether enteric neural crest-derived cells (ENCCs) that are transplanted into the aganglionic gut can migrate, proliferate, and differentiate in a normal manner remains unanswered. Thus, we designed this study to compare the behavior of ENCCs transplanted into the aganglionic gut of endothelin receptor B knockout (Ednrb-KO) mice versus wild-type (WT) mice. METHODS: ENCCs were isolated from the fetal guts of Sox10 transgenic mice, in which ENCCs were labeled with an enhanced green fluorescent protein, Venus, on an embryonic day 18.5 (E18.5). Neurospheres were generated and transplanted into the aganglionic region of either Ednrb-KO mice gut, or WT mice gut that had not yet been colonized, on E12.5. Time-lapse imaging of the transplanted ENCCs was performed after 24, 48, and 72 h of culture. Neuronal differentiation was evaluated using whole-mount immunohistochemistry. RESULTS: Sox10-positive ENCCs were seen to successfully migrate into the myenteric region of the aganglionic gut following transplantation in both the Ednrb-KO and WT mice. The ratio of Tuj1-positive/Sox10-positive cells was significantly increased after 72 h of culture compared to 24 h in the Ednrb-KO mice, which suggests that the transplanted ENCCs differentiated over time. In addition, at the 72 h timepoint, neuronal differentiation of transplanted ENCC in the aganglionic gut of Ednrb-KO mice was significantly increased compared to that of WT mice. CONCLUSIONS: The results of our study demonstrated that transplanted ENCCs migrated into the myenteric region of the aganglionic recipient gut in mice. The increased neuronal differentiation of transplanted ENCC in Endrb-KO mice gut suggests that the microenvironment of this region affects ENCC behavior following transplantation. Further research to explore the characteristics of this microenvironment will improve the potential of developing cell therapy to treat HD patients.

Differentiation of enteric neural crest cells transplanted from SOX10-Venus mouse embryonic stem cells into the gut of the endothelin receptor B null mouse model.

PURPOSE: Failure of enteric neural crest-derived cells (ENCCs) to correctly colonize the embryonic gut results in Hirschsprung's disease (HD). Embryonic stem cells (ESCs) have the potential to differentiate into all tissue-specific cells and lineages, including ENCCs. We investigated the cellular differentiation of ESCs from Sox10-Venus + mice into both control and endothelin receptor-B knockout (Ednrb KO) mouse gut to assess each region. METHODS: We established ESCs from Sox10-Venus + mice. These cells were cultured for 2 days, then selected and co-cultured with either a dissociated control or Sox10-Venus - Ednrb KO mouse gut (both small intestine and colon) on embryonic day (E) 13.5. Four days later, cells were immunolabeled for Tuj1 and visualized using confocal microscopy. RESULTS: Confocal microscopy revealed that transplanted Sox10-Venu + cells from ESCs migrated extensively within the host gut. Moreover, Tuj1-positive neurites were detected in the transplanted ESCs. Tuj1 expression was significantly decreased in aganglionic HD colon compared to controls (p < 0.05) and the HD small intestine (p < 0.05). CONCLUSIONS: This study demonstrated that an appropriate host environment is crucial for normal and complete colonization of the gut. Further investigations are required to confirm whether modifying this environment can improve the results of this model.

Do Parameatal Urethral Cysts in Children Need Surgical Excision?

OBJECTIVE: To examine pathophysiology of parameatal urethral cyst (PUC) with comparison between the surgical excision group and the spontaneous resolution group. METHODS: We retrospectively reviewed all patients diagnosed with PUC and aged ≤15 years. Initially, all the patients received observation without any treatment. The indication of surgical excision was family preference. The patients were analyzed according to their sex, age, symptoms, clinical course, and pathological examination findings. RESULTS: Among the 54 boys visited our hospital for PUC. The median age at presentation was 35 (IQR: 12-50) months, including 7 (13.0%) neonates cases. In total, 38 (70.4%) patients were underwent surgical excision, 12 (22.2%) had spontaneous resolution during observation, 1 (1.9%) had observation without resolution, and 3 (5.6%) were lost to follow-up. The median size of PUC at the first visit was significantly larger in the surgical excision group (5 mm median, IQR 3-5) than in the spontaneous resolution group (1.5 mm median, IQR 1-2.5) (P <.0001). In this study, PUC ≥5 mm in diameter did not have spontaneous resolution. CONCLUSION: This is the largest study of PUC conducted at a single institute. This study indicated that 22% of PUCs had spontaneous resolution, and PUCs <5 mm had potential for spontaneous resolution. The results recommend an observation of at least 5.5 months for patients with asymptomatic PUC <5 mm. By contrast, we recommend the surgical excision for symptomatic PUC ≥5 mm according to the family preference.

In vitro investigation of the differentiation of enteric neural crest-derived cells following transplantation of aganglionic gut in a mouse model.

PURPOSE: Cell therapy is a promising approach to treat enteric neuropathies such as Hirschsprung disease (HD). Recent studies have reported that enteric neurons derived from stem cells (ENCCs) can be grafted into the HD colon. Thus, we investigated the migration and generation of enteric neurospheres from SOX10-VENUS+ mice after transplantation into control or Ednrb KO mice, which are a model of HD. METHODS: Single-cell suspensions were isolated from the fetal guts of SOX10-VENUS+ mice E13.5 and dissociated. These cells were cultured for 7 days under non-adherent conditions to generate neurospheres, which were co-cultured with dissociated control or SOX10-VENUS- Ednrb KO mouse gut on E13.5. 4 days later, these cells were fixed and the expression of the neuronal marker, Tuj1, was evaluated. RESULTS: Transplanted neurospheres had undergone abundant neuronal migration and differentiation of ENCCs in the control gut compared with the HD gut. The average length and intersections were significantly decreased in HD colon compared with controls (p < 0.05), and a similar pattern was observed in the HD small intestine (p < 0.05). CONCLUSIONS: We demonstrated that transplanted ENCCs did not differentiate properly in HD gut. These results highlight the importance of the neuronal environment in the recipient gut for enteric nervous system development.

Forty-Year Experience Alleviating Postoperative Hirschsprung-Associated Enterocolitis by Complete Full-Thickness Posterior Rectal Cuff Excision. The Anorectal Line Eliminates Problematic Anastomoses.

Introduction: A modified pull-through (PT) distinguished by complete full-thickness removal of the posterior rectal cuff, initially developed as an open procedure in 1980, has been performed with laparoscopic assistance since 1997. Postoperative bowel dysfunction improved when the anatomic landmark for PT surgery was revised from the dentate line (DL) to the anorectal (or Herrmann's) line (ARL) in 2007. A 40-year (1980-2019) review of 153 consecutive rectal/rectosigmoid type Hirschsprung's disease (HD) patients is presented. Methods: Data for postoperative bowel dysfunction and Hirschsprung-associated enterocolitis (HAEC) classified according to the American Pediatric Surgical Association (APSA) scale were obtained retrospectively. Results: PT was open (n = 43) and laparoscopic (n = 110). Dissection was DL (n = 57) and ARL (n = 96). Over 40 years, 5/153 patients (3.3%) had postoperative obstructive symptoms (POS), and 10/153 patients (6.5%) had 13 episodes of postoperative HAEC; APSA grades were: I (n = 4); II (n = 8); and III: (n = 1) presenting with explosive diarrhea (10/13; 76.9%), fever (10/13; 76.9%), abdominal distension (9/13; 69.2%), or bloody stools/shock (1/13 with grade III; 7.7%). The grade III case had histologically-proven transitional zone PT. Postoperative HAEC developed in 3/5 (60.0%) POS+ patients and 7/148 (4.7%) POS- patients (P = .002). Symptom duration and treatment were not correlated with APSA grades. Conclusions: Complete full-thickness posterior rectal cuff excision and using the ARL reduced postoperative HAEC significantly in this series. Despite being anatomically distinct, the DL is inadequate as a precise landmark for PT surgery because it lacks functional relevance. The APSA scale could benefit from timely review to improve its clinical and prognostic value.

Dysgerminoma with Estrogen-Producing Functioning Stroma Presenting Precocious Puberty.

Dysgerminoma is a malignant ovarian germ cell tumor, and unlike sex-cord stromal tumors, endocrine manifestation is considered rare. Here, we report the first case of dysgerminoma presenting precocious puberty. The patient is a 7-year-old girl who presented with a breast development in Tanner stage 3. Serum estradiol (E2) was markedly elevated while luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were suppressed below the detection limit. Microscopically, the right ovarian mass displayed nests of large polygonal cells and fibrous septa which were focally concentrated by theca-like plump spindle cells. Immunohistochemistry revealed that the spindle cells expressed various steroidogenic enzymes involved in estrogen biosynthesis including P450 aromatase. The tumor was diagnosed with pure dysgerminoma with estrogen-producing functioning stroma. After the operation, serum E2 declined below the detection limit; LH and FSH returned within the normal range. This case demonstrates that even a conventional dysgerminoma can present endocrine manifestation through functioning stroma.

Can Intraoperative Video Recordings Contribute to Improving Laparoscopic Percutaneous Extraperitoneal Closure in Children with Inguinal Hernia and Prevent Recurrence? A Pilot Study.

Aim: We reviewed intraoperative video recordings (IVRs) of laparoscopic percutaneous extraperitoneal closure (LPEC) for inguinal hernia in children blindly to assess performance. Methods: IVRs of 183 LPEC performed between April 2013 and March 2016, graded by the operating surgeon as difficult (D; n = 8), straightforward (S; n = 96), or easy (E; n = 79), were scored by a panel of reviewers with advanced (group A; >400 LPEC cases; n = 5), intermediate (group I; 50-150 cases; n = 5), and basic (group B; <10 cases; n = 5) experience, according to suturing, dissection plane, vas/vessel dissection, bleeding, and peritoneal injury. They also allocated a recurrence risk rank (RRR; highest = 6; lowest = 1) for each IVR. Mean score variance for each IVR was also compared between reviewers. Results: There was one recurrence (R; 4-year-old male; level E). RRR were: 1, 2, and 2 for reviewers A, I, and B, respectively. Reviewer A scores for "suturing" and "bleeding," and reviewer I scores for "dissection plane" and "peritoneal injury" correlated significantly with RRR. No reviewer B scores correlated with RRR. Score variance between A and I and A and B for cases D1 and D2 were statistically significant. Conclusion: Advanced reviewers showed greatest variance, questioning the validity of whether experience alone improves surgical technique.

Decreased expression of ß1 integrin in enteric neural crest cells of the endothelin receptor B null mouse model.

BACKGROUND: Interactions between enteric neural crest-derived cells (ENCC) and the surrounding intestinal microenvironment, such as the extracellular matrix (ECM), are critical for regulating enteric nervous system (ENS) development. Integrins are the major receptors for ECM molecules, such as laminin, which have been reported to be involved in the pathogenesis of Hirschsprung's disease. In this study, we examined the expression of ß1 integrin in the endothelin receptor B (Ednrb) knock out (KO) mouse gut, which presents with an aganglionic colon. METHODS: A Sox10-Venus-positive Ednrb KO mouse, where ENCC is labeled with fluorescent protein, 'Venus', was created. Sox10-Venus-positive Ednrb wild type (WT) were used as controls. Small intestine, proximal colon and distal colon were dissected on E13.5 and E15.5 and ß1 integrin expression of the gut tissue was examined by immunohistochemistry and real time RT-PCR. The cells of the gut dissected on E11.5 were isolated and cultured for 2 days. Venus-positive ENCC were immunostained with ß1 integrin and Tuj-1, which is a marker for neurons. RESULTS: The expression of ß1 integrin was not significantly different between KO and WT in all parts of the gut examined. However, the ß1 integrin expression in the isolated ENCC was significantly decreased in KO compared to WT. The average threshold area was 42.98 ± 17.47% in KO and 73.53 ± 13.77 in WT (p < 0.001). CONCLUSIONS: We demonstrated that ß1 integrin expression was specifically decreased in ENCC in Ednrb KO mice. Our results suggest that impaired interaction between integrin and its ligands may disturb normal ENS development, resulting in an aganglionic colon.

DPP4 inhibitor reinforces cell junction proteins in mouse model of short bowel syndrome.

PURPOSE: Bacterial overgrowth commonly occurs and favors bacterial translocation in short bowel syndrome (SBS). Glucagon-like peptide-2 (GLP-2) is effective for treating SBS, but is rapidly inactivated by dipeptidyl peptidase IV (DPP4). DPP4 inhibitor (DPP4I) is known to be effective for treating SBS. Here, we investigated cell junction protein function following DPP4I administration in a mouse model of SBS. METHODS: Mice were divided into four groups: naïve (n = 5), naïve + DPP4I (n = 6), control (n = 6), and DPP4I (n = 5). All control and DPP4I mice had 50% of their proximal small bowel resected. DPP4I or normal saline was administered orally twice daily from days 1-7 postoperatively. The functions of cell junction proteins were assessed by RT-PCR and immunohistochemistry. Body weights and blood glucose levels were recorded. RESULTS: E-Cadherin was significantly higher in the DPP4I group than in the control group. E-Cadherin, occludin, and claudin-4 were significantly higher in the naïve group than in the control group. Positive staining for E-cadherin and occludin varied widely between the control and DPP4I groups. CONCLUSION: Up-regulation of E-cadherin and occludin by DPP4I may be correlated with the anti-inflammatory action of DPP4I. Therefore, DPP4I may reduce bacterial translocation in SBS.

Animal Models of Hirschsprung's Disease: State of the Art in Translating Experimental Research to the Bedside.

Hirschsprung's disease (HSCR) is caused by incomplete colonization of enteric neural crest-derived cell (ENCC) in the bowel, the failure of ENCCs to proliferate, differentiate, and migrate leads to an absence of enteric neurons in the distal colon, resulting in colonic motility dysfunction. Various animal models of HSCR have been important in the understanding of the anatomy and pathophysiology of the disease and in the discovery of genes involved in HSCR. Four types of HSCR animal models have been developed: teratogen-induced, surgically created, naturally occurring models, and knockout models. Mutations in several genes affect enteric nervous system (ENS) development and can have pleiotropic effects on this system. Furthermore, certain animal models are informative regarding how such molecules control the development and functional differentiation of the ENS. In this article, we summarize recent advances in this field and highlight opportunities for new discoveries.

Altered expression of laminin alpha1 in aganglionic colon of endothelin receptor-B null mouse model of Hirschsprung's disease.

PURPOSE: Laminin, an extracellular matrix molecule, is essential for normal development of the nervous system. The alpha1 subunit of laminin-1 (LAMA1) has been reported to promote neurites and outgrowth and is expressed only during embryogenesis. Previously, we developed a Sox10 transgenic version of the Endothelin receptor-B (Ednrb) mouse to visualize Enteric neural crest-derived cell (ENCC)s with a green fluorescent protein, Venus. We designed this study to investigate the expression of LAMA1 using Sox10-VENUS mice gut. METHODS: We harvested the gut on days 13.5 (E13.5) and 15.5 (E15.5) of gestation. Sox10-VENUS+/Ednrb -/- mice (n = 8) were compared with Sox10-VENUS+/Ednrb +/+ mice (n = 8) as controls. Gene expression of LAMA1 was analysed by real-time RT-PCR. Fluorescent immunohistochemistry was performed to assess protein distribution. RESULTS: The relative mRNA expression levels of LAMA1 were significantly increased in HD in the proximal and distal colon on E15.5 compared to controls (p < 0.05), whereas there were no significant differences on E13.5. LAMA1 was expressed in the serosa, submucosa and basal lamina in the gut, and was markedly increased in the proximal and distal colon of HD on E15.5. CONCLUSIONS: Altered LAMA1 expression in the aganglionic region may contribute to impaired ENCC migration, resulting in HD. These data could help in understanding the pathophysiologic interactions between LAMA1 and ENCC migration.

Hirschsprung's disease in the laparoscopic transanal pull-through era: implications of age at surgery and technical aspects.

AIM: Detailed implications of age at laparoscopic transanal pull-through (LTAPT) on postoperative bowel function (POBF) in Hirschsprung's disease (HD) are somewhat obscure because of a spectrum of factors. METHODS: Age at surgery was used to categorize 106 consecutive postoperative HD cases treated by our modified LTAPT (JLTPAT) between 1997 and 2015; group A: < 3 months old (n = 31); group B: 3-11 months old (n = 44); group C: 1-3 years old (n = 19); and group D: ≥ 4 years old (n = 12). POBF was assessed by reviewing outpatient records 1, 3, 5, 7, and 10 years after JLTAPT prospectively and scoring each of 5 criteria on a scale of 0-2; best score = 10. RESULTS: Only operative time was statistically longer in group D versus groups A, B, and C. Differences in gender ratios, blood loss, duration of follow-up, and POBF scores were not statistically significant. Mean POBF scores over time were: group A: 6.8, 7.6, 8.4, 8.6, and 8.4; group B: 7.1, 7.8, 8.3, 8.5, and 9.0; group C: 6.9, 7.9, 8.1, 8.3, and 8.6; group D: 7.0, 7.4, 8.2, 8.1, and 8.5, respectively. CONCLUSION: Age at JLTAPT was not correlated with POBF in HD.

Increased expression of Semaphorin 3A in the endothelin receptor-B null mouse model of Hirschsprung disease.

PURPOSE: Semaphorins are guidance cues for developing neurons, implicated in the determination of the migratory pathway of neural crest-derived neural precursors during enteric nervous system development. Recently, it has been reported that Semaphorin 3A (SEMA3A) expression is up-regulated in the aganglionic colon in Hirschsprung disease (HD) patients, suggesting that increased SEMA3A expression may be a risk factor for HD. Thus, the aim of our study was to determine the expression of SEMA3A using Sox10-Venus mice gut. METHODS: We harvested the gut on postnatal day 2 (P2). SOX10-Venus+/EDNRB-/- mice were compared with SOX10-Venus+/EDNRB+/+ mice as controls. QRT-PCR was performed to determine gene expression of SEMA3A (n=8). Fluorescent immunohistochemistry was performed to assess protein distribution. RESULTS: On P2, gene expression levels of SEMA3A were significantly increased in the HD group compared to controls in the proximal and distal colon (p<0.05). Laser scanning microscopy revealed SEMA3A expression was localized within the submucosa and muscle layer of the gut in both HD and controls. In HD, SEMA3A was highly expressed in the proximal and distal colon. CONCLUSIONS: In the present study, we demonstrated that SEMA3A expression is increased in the EDNRB-/- HD model on P2, suggesting that SEMA3A may interfere with ENCC migration, resulting in an absence of enteric neurons.

The effect of laminin-1 on enteric neural crest-derived cell migration in the Hirschsprung's disease mouse model.

BACKGROUND/AIM: Laminin-1 regulates neurite outgrowth in various neuronal cells. We have previously demonstrated that laminin-1 promotes enteric neural crest-derived cell (ENCC) migration by using Sox10-VENUS transgenic mice, in which ENCCs are labeled with a green fluorescent protein, Venus. Mice lacking the endothelin-B receptor gene, Ednrb -/- mice, are widely used as a model for Hirschsprung's disease (HD). The aim of this study was to investigate the effects of laminin-1on ENCC migration in Sox10-VENUS+/Ednrb -/- mice, a newly created HD mice model. METHODS: Fetal guts were dissected on embryonic day 12.5 (E12.5). Specimens were incubated either with, or without laminin-1 for 24 h and images were taken under a stereoscopic microscope. The length from the stomach to the wavefront of ENCC migration (L-E) and the total length of the gut (L-G) were measured. Changes in the ratio of L-E to L-G (L-E/L-G) after 24 h were calculated. RESULTS: On E12.5, the wavefront of ENCC migration in the HD gut samples was located in the midgut, whereas the wavefront of ENCC in Sox10-VENUS+/Ednrb +/+ (WT) samples had reached the hindgut. After 24 h, L-E/L-G had increased by 1.49%, from 34.97 to 36.46%, in HD gut and had increased by 1.07%, from 48.08 to 49.15%, in HD with laminin-1, suggesting there was no positive effect of laminin-1 administration on ENCC migration in HD. CONCLUSIONS: Our results suggest that laminin-1 does not have a positive effect on ENCC migration in HD mice on E12.5, in contrast to the phenomenon seen in normal mice gut specimens, where laminin-1 promotes ENCC migration during the same period. This suggests that there is an impairment in the interaction between ENCC and extracellular environmental factors, which are required for normal development of the enteric nervous system, resulting in an aganglionic colon in HD.

Altered differentiation of enteric neural crest-derived cells from endothelin receptor-B null mouse model of Hirschsprung's disease.

PURPOSE: Hirschsprung's disease (HD) is caused by a failure of enteric neural crest-derived cells (ENCC) to colonize the bowel, resulting in an absence of the enteric nervous system (ENS). Previously, we developed a Sox10 transgenic version of the Endothelin receptor-B (Ednrb) mouse to visualize ENCC with the green fluorescent protein, Venus. The aim of this study was to isolate Sox10-Venus+ cells, which are differentiated neurons and glial cells in the ENS, and analyze these cells using Sox10-Venus mice gut. METHODS: The mid-and hindgut of Sox10-Venus+/Ednrb +/+ and Sox10-Venus+/Ednrb -/- at E13.5 and E15.5 were dissected and cells were dissociated. Sox10-Venus+ cells were then isolated. Expression of PGP9.5 and GFAP were evaluated neurospheres using laser scanning microscopy. RESULTS: 7 days after incubation, Sox10-Venus+ cells colonized the neurosphere. There were no significant differences in PGP9.5 expressions on E13.5 and E15.5. GFAP was significantly increased in HD compared to controls on E15.5 (P < 0.05). CONCLUSIONS: Our results suggest increased glial differentiation causes an imbalance in ENCC lineages, leading to a disruption of normal ENS development in this HD model. Isolation of ENCC provides an opportunity to investigate the ENS with purity and might be a useful tool for modeling cell therapy approaches to HD.