Is Hirschsprung disease a purely neurological condition? A study of the Actin G2 smooth muscle gene in Hirschsprung disease

Early intervention in Hirschsprung's disease: effects on enterocolitis and surgical outcomes

BACKGROUND

The timing of surgical intervention for Hirschsprung's disease (HSCR) has been a topic of continued discussion. The objective of this study was to evaluate the significance of age at surgery in the management of HSCR by conducting a comparative analysis of the correlation between surgical age and midterm outcomes.

METHODS

We conducted a retrospective analysis of children with HSCR who underwent one-stage laparoscopic assisted pull-through surgery with modified Swenson technology at our hospital between 2015 and 2019. The study population was stratified into two groups based on surgical age: patients who underwent surgery within a period of less than 3 months and those who underwent surgery between 3 and 12 months. The basic conditions, complications at 3-7 years after surgery, anal function (Rintala scale) and quality of life (PedsQLTM4.0) were compared between the groups.

RESULTS

A total of 235 children (196 males and 39 females) were included in the study. No statistically significant differences in postoperative bowel function (P = 0.968) or quality of life (P = 0.32) were found between the two groups. However, there was a significant reduction in the incidence of Hirschsprung-associated enterocolitis (HAEC) among individuals under the age of three months prior to undergoing surgical intervention (69.1%) compared to the incidence observed postsurgery (30.9%). This difference was statistically significant (P < 0.001).

CONCLUSION

In the current study, the age at which surgery was performed did not exhibit a discernible inclination towards influencing mid-term anal function or quality of life. Early surgical intervention can effectively diminish the occurrence of HAEC, minimize the extent of bowel resection, and expedite the duration of the surgical procedure.

Actin polymerization and depolymerization in developing vertebrates

Development is a complex process that occurs throughout the life cycle. F-actin, a major component of the cytoskeleton, is essential for the morphogenesis of tissues and organs during development. F-actin is formed by the polymerization of G-actin, and the dynamic balance of polymerization and depolymerization ensures proper cellular function. Disruption of this balance results in various abnormalities and defects or even embryonic lethality. Here, we reviewed recent findings on the structure of G-actin and F-actin and the polymerization of G-actin to F-actin. We also focused on the functions of actin isoforms and the underlying mechanisms of actin polymerization/depolymerization in cellular and organic morphogenesis during development. This information will extend our understanding of the role of actin polymerization in the physiologic or pathologic processes during development and may open new avenues for developing therapeutics for embryonic developmental abnormalities or tissue regeneration.

Optimal timing of definitive surgery for Hirschsprung's disease to achieve better long-term bowel function

PURPOSE

Few studies have focused on the operative age for Hirschsprung's disease (HD). We evaluated the optimal timing of surgery in HD patients based on their long-term bowel function.

METHODS

HD was diagnosed in 65 pediatric patients in our institute between 1992 and 2018. Twenty-five patients underwent the Soave-Denda procedure (SD) and 40 underwent transanal endorectal pull-through (TA). We divided these patients into two groups: those who underwent surgery at < 6 months of age (younger group) and those who underwent surgery at 6-12 months of age (older group). We assessed bowel function at 5, 7, and 9 years of age.

RESULTS

The bowel function of the patients who underwent the SD did not differ significantly between the groups. Similarly, the total bowel-function scores of the patients who underwent TA did not differ between the groups at any age. However, the soiling score at 7 years of age in the older group of patients who underwent TA was significantly lower than that in the younger group (p = 0.02).

CONCLUSIONS

Our data suggest that to achieve optimal bowel function, TA should be performed at < 6 months of age.

Visceral myopathy diagnosed by a de novo ACTG2 mutation in a patient with chronic intestinal pseudo-obstruction-a case report

Visceral myopathy is a rare genetic disorder that commonly affects the digestive and renal systems. Manifestations include a clinical spectrum covering chronic intestinal pseudo-obstruction (CIPO) and megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS). The smooth muscle actin γ-2 gene (ACTG2) is one of the most common disease-causing genes. Here, we present a case of pediatric intestinal pseudo-obstruction associated with a novel missense ACTG2 mutation, c.588G>C/p.E196D. His parents had no this mutation, which suggested the possibility of spontaneous mutation. Amino acid conservation analysis of γ-2 actin showed replacement of glutamate at position 196 by aspartate. The patient suffered from recurrent episodes of abdominal bloating, undergone repeated gastrointestinal surgery, had feeding difficulties, and required long-term parenteral nutrition support. The patient had no other specific symptoms or underlying diseases. X-ray of the abdomen showed dilation of the intestine as well as an air-fluid pattern. The manifestations of biopsy were various. All biochemical tests were normal, and the possibility of secondary intestinal pseudo-obstruction was excluded. The mutation site of ACTG2 in the present study has not been previously described in patients with visceral myopathy, and thus, our study reveals a novel mutation of ACTG2-associated visceral myopathy in a patient with CIPO. This report can serve as a reference for future research and further expands the map of genetic variation for visceral myopathy.

Inhibition of ROCK signaling pathway accelerates enteric neural crest cell-based therapy after transplantation in a rat hypoganglionic model

BACKGROUND

Hirschsprung's disease (HSCR) is a congenital gastrointestinal disorder, characterized by enteric ganglia absence in part or entire of the colon, due to abnormal colonization and migration of enteric neural crest cells (ENCCs) during development. Currently, besides surgery which is the main therapy for HSCR, the potential of stem cell-based transplantation was investigated as an alternative option. Although promising, it has limitations, including poor survival, differentiation, and migration of the grafted cells. We hypothesized that modulation of extracellular factors during transplantation could promote ENCCs proliferation and migration, leading to increased transplantation efficiency. Considering that the RhoA/ROCK pathway is highly involved in cytoskeletal dynamics and neurite growth, our study explored the effect of inhibition of this pathway to improve the success of ENCCs transplantation.

METHODS

Enteric neural crest cells were isolated from rat embryos and labeled with a GFP-tag. Cell viability, apoptosis, differentiation, and migration assays were performed with and without RhoA/ROCK inhibition. Labeled ENCCs were transplanted into the muscle layer of an induced hypoganglionic rat model followed by intraperitoneal injections of ROCK inhibitor. The transplanted segments were collected 3 weeks after for histological analysis.

KEY RESULTS

Our results showed that inhibition of ROCK increased viable cell number, differentiation, and migration of ENCCs in vitro. Moreover, transplantation of labeled ENCCs into the hypoganglionic model showed enhanced distribution of grafted ENCCs, upon treatment with ROCK inhibitor.

CONCLUSIONS AND INFERENCES

ROCK inhibitors influence ENCCs growth and migration in vitro and in vivo, and should be considered to improve the efficiency of ENCCs transplantation.

Accuracy of colonic mucosal patterns at contrast enema for diagnosis of Hirschsprung disease

BACKGROUND

Various patterns of colonic mucosal irregularity have been recorded on contrast enema, each with individually very low sensitivity, but high specificity.

OBJECTIVE

To assess the accuracy of the radiologic features of Hirschsprung disease utilising a unifying stratification of any form of colonic mucosal irregularity on contrast enema.

MATERIALS AND METHODS

We conducted a retrospective study of children with suspected Hirschsprung disease managed at a tertiary South African hospital from January 2009 through April 2015. Three observers independently reviewed abdominal radiographs and contrast enemas. The enema analysis included a unifying category of any form of colonic mucosal irregularity. Radiologic features were compared with rectal biopsy results. We used descriptive statistics and the Fisher exact test to compare the radiologic features of children with and without Hirschsprung disease.

RESULTS

Ninety-two children with median age of 37 days (range 3 days to 11 years) were included; 50 had biopsy-proven Hirschsprung disease. On enema, any mucosal irregularity, a transition zone and recto-sigmoid ratio inversion were associated with Hirschsprung disease (all P<0.01). Mucosal irregularity showed 96% sensitivity (95% confidence interval [CI] 86.3-99.5) and 71.4% specificity (CI 55.4-84.3); a transition zone showed 86% sensitivity (CI 73.3-94.2) and 90.5% specificity (CI 77.4-97.3); and recto-sigmoid ratio inversion showed 78% sensitivity (CI 64.0-88.5) and 83.3% specificity (CI 68.3-93.0).

CONCLUSION

Colonic mucosal irregularity on contrast enema has high sensitivity and moderate specificity for Hirschsprung disease.