Morphological abnormalities in the innervation of the atretic segment of bowel in neonates with intestinal atresia

Short Bowel Syndrome and Dysmotility

Due to recent advances, the mortality due to short bowel syndrome (SBS) has significantly decreased, but the morbidities are still high. Morbidities arising specifically due to dysmotility in SBS include feeding intolerance, prolonged dependence on parenteral nutrition, and associated complications such as intestinal failure associated liver disease, and bloodstream infections. The understanding of the pathogenesis of dysmotility in SBS has improved vastly. However, the tools to diagnose dysmotility in SBS in infants are restrictive, and the medical therapies to treat dysmotility are limited. Surgical techniques available for the treatment after failure of conservative management of dysmotility offer hope but carry their associated risks. The evidence to support either the medical therapies or the surgical techniques to treat dysmotility in SBS in children is scarce and weak. Development of newer therapies and efforts to build evidence to support currently available treatments in treating dysmotility in SBS is needed.

Intestinal dysmotility after bowel resection in rats is associated with decreased ghrelin and vimentin expression and loss of intestinal cells of Cajal

This study provides novel insight into the mechanisms of intestinal dysmotility following massive small bowel resection. We show that 2 wk after bowel resection in rats, impaired intestinal motility was associated with loss of interstitial cells of Cajal (ICC; downregulation of transmembrane member 16A (TMEM16A) and c-kit expression) as well as with decreased vimentin, desmin, and ghrelin levels. Impaired intestinal motility led to a decrease in final body weight, suggesting less effective nutrient absorption. The purpose of this study was to evaluate the mechanisms of intestinal motility in a rat model of short bowel syndrome (SBS). Rats were divided into three groups: Sham rats underwent bowel transection; SBS-NSI rats underwent a 75% bowel resection and presented with normal intestinal size (NSI) at euthanasia and hypermotility patterns; SBS-DYS showed dysmotile (DYS) enlarged intestine and inhibited motility patterns. Animals were euthanized after 2 wk. Illumina's digital gene expression (DGE) analysis was used to determine the intestinal motility-related gene expression profiling in mucosal samples. Intestinal motility-related and ICC genes and protein expression in intestinal muscle layer were determined using real-time PCR, Western blotting, and immunohistochemistry. Gastrointestinal tract motility was studied by microcomputer tomography. From 10 Ca²⁺ signaling pathway-related genes, six genes in jejunum and seven genes in ileum were downregulated in SBS vs. Sham animals. Downregulation of TMEM16A mRNA and protein was confirmed by real-time PCR. Rapid intestinal transit time in SBS-NSI rats correlated with a mild decrease in TMEM16A, c-kit, and vimentin mRNA and protein expression (vs/. Sham animals). SBS-DYS rats demonstrated enlarged intestinal loops and delayed small intestinal emptying (on imaging studies) that were correlated with marked downregulation in TMEM16A, c-kit, vimentin, and ghrelin mRNA and protein levels compared with the other two groups. In conclusion, 2 wk following massive bowel resection in rats, impaired intestinal motility was associated with decreased vimentin and ghrelin gene and protein levels as well as loss of ICC (c-kit and TMEM16A).NEW & NOTEWORTHY This study provides novel insight into the mechanisms of intestinal dysmotility following massive small bowel resection. We show that 2 weeks after bowel resection in rats, impaired intestinal motility was associated with loss of interstitial cells of Cajal (downregulation of TMEM 16A, and c-kit expression) as well as with decreased vimentin, desmin, and ghrelin levels. Impaired intestinal motility led to decrease in final body weight, suggesting less effective nutrient absorption.

Novel insights into the histology of jejunoileal atresia and its therapeutic implications

AIM

To study the histology of resected specimens of jejunoileal atresia (JIA) and to explore its probable therapeutic implications.

METHODS

Biopsies were taken from the resected specimens of 32 patients of JIA. Sections were taken at the atretic ends and successively at every 5 cm in resected proximal bowel. They were stained for light microscopy and immunohistochemistry for CD117 (Interstitial cell of Cajal), α smooth muscle antibody (SMA), neuron filament protein (NFP) and calretinin. Histological findings on light microscopy and immune reactivity intensity for NFP, calretinin and α-SMA were recorded. Time taken to achieve full enteral nutrition (FEN; defined as attainment of oral feeds at 100 ml/kg/day without any intravenous fluid supplementation) was recorded and correlated with CD117 count by non-parametric Spearman rank correlation coefficient.

RESULTS

Light microscopy failed to detect any abnormality in majority (n = 27, 84%) of JIA specimens. Mucosal ulceration (7.8%), submucosal inflammatory cells (8%), focal muscle thinning (2.5%), decreased ganglion cells and nerve fibers (3.8%) were noted on light microscopy. However all of them had normal α SMA, calretinin and NFP immunoreactivity. Mean ICC counts at proximal and distal atretic segment were 6.56 ± 3.79 and 8.37 ± 3.21 per HPF respectively. Serial sections in proximal dilated segment did not reveal any definite or well demarcated increase in ICC counts. CD117 counts at the proximal cut end of atresia was less than 6 per high power field (hpf) in 15 patients (46.8%) while at the site of anastomosis a count of more than 6/hpf was observed in 73% patients. There was no direct correlation of ICC counts with attainment of FEN.

CONCLUSION

Absence of major morphological abnormalities in the proximal dilated bowel contradicts the findings of earlier studies on histology of JIA in smaller cohorts. Our observations reiterate that bowel plication rather than massive bowel resection should be the preferred management in babies with JIA.

LEVEL OF EVIDENCE

Prognosis study (Level II).

Abnormalities of the intestinal pacemaker cells, enteric neurons, and smooth muscle in intestinal atresia

BACKGROUND:

Small bowel atresia is a congenital disorder that carves a substantial morbidity. Numerous postoperative gastrointestinal motility problems occur. The underlying cause of this motility disorder is still unclear. Interstitial cells of Cajal (ICC) play a major role in gastrointestinal motility.

AIMS AND OBJECTIVES:

To investigate the morphological changes of enteric nervous system and ICC in small bowel atresia.

MATERIAL AND METHODS:

Resected small bowel specimen from affected patients (n=15) were divided into three parts (proximal, distal, atretic). Standard histology and immunohistochemistry with anti C-KIT receptor antibody (CD117), calretinin and α-SMA was carried out. The density of myenteric ICCs in the proximal, atretic and distal parts was demonstrated by CD 117 while Calretinin was used for ganglion cells and nerve bundles, α-SMA highlighted muscle hypertrophy.

RESULT AND CONCLUSION:

The proximal and distal bowel revealed clear changes in the morphology and density of enteric nervous system and interstitial cells of Cajal..

A Pilot Study on Histopathology of the Jejunoileal Atresia-Can it Be Used as a Guide to Determine the Length of Adequate Resection?

Introduction:

Some studies reported that there is abnormality in the histopathology of atretic bowel in jejunoileal atresia (JIA). We have made an attempt to assess sequential histopathologic changes in the resected atretic segment.

Material and methods:

The histopathology of the resected segment was evaluated at 1, 3, 5, 7, 9, and 11 cm from atretic end (Sections A to F, respectively). The ratio of inner and outer muscle layer (measured by NIS-Element D software) was calculated at every section. Immunohistochemistry for α-smooth muscle actin (α-SMA) was also done. The findings were compared with control.

Results:

In control set (n = 5), the ratio of inner and outer muscle layer was 1.03. In patients with JIA, the ratio was 0.68 to 0.9 at section A. This ratio varied at various sections in all specimens. In section F, this ratio was 0.95 to 1.09, which is close to control ratio. There were no specific findings related to α-SMA staining.

Conclusions:

It appears that the bowel proximal to the atresia is abnormal for a varied length. It may be a possibility that this abnormality is present at least up to about 10 cm proximal to atresia. Adequate resection is important for optimal outcome.

Presentation and outcome of treatment of jejunoileal atresia in Nigeria

BACKGROUND

Intestinal atresia is a common cause of neonatal intestinal obstruction. Previous reports from Nigeria have indicated a high mortality rate. This is a report of current outcome review from one tertiary center.

PATIENTS AND METHODS

A retrospective analysis of infants managed for jejunoileal atresia in 10 years (2005-2014). The information retrieved from patients' records was analyzed using SPSS 17.

RESULTS

There were 38 patients (19 boys and 19 girls) aged 1-28 days (median 4 days). Twenty-four patients (63.2%) presented after 48 h of life. Twenty-five (65.8%) had jejunal atresia and 13 (34.2%) had ileal atresia. Six patients had associated anomalies. The most common atresia was type III (39.5%, 15 patients). Twenty-eight (73.7%) patients had a resection of the atresia and anastomosis and others had enterostomies. Total parenteral nutrition and neonatal intensive care support were not available during the period of the study. Bowel function was established within 1 week and 27 (71.1%) patients commenced oral feeding. Twenty-six (68.4%) patients had postoperative complications resulting in prolonged hospital stay of 2-44 days (median = 13). Mortality was 34.2% (13 patients). Factors that significantly affected mortality were intestinal necrosis at presentation, postoperative complications, and severe malnutrition.

CONCLUSION

Intestinal atresia is still associated with unacceptably high morbidity and mortality, due to late presentation, and lack neonatal intensive care services and parenteral nutritional support. Efforts need to be intensified to address these factors to improve outcome.

Involvement of the enteroendocrine system in intestinal obstruction

INTRODUCTION

Intestinal atresia, a rare congenital condition, is often associated with intestinal motility disorders despite adequate neonatal surgery. Previous studies have focused on changes in the enteric nervous system (ENS). We hypothesized that other components of the digestive tract could be involved in this condition.

MATERIAL AND METHODS

In a rat model of surgically-induced intestinal obstruction, a transcriptome analysis was performed to measure the global gene expression. Then, analyzes were focused on genes expressed in ENS and neuroendocrine cells. Rat fetus small intestines at different developmental stages (ED15, ED17, ED19 and ED21, (n = 22)) were studied as controls and compared to the upper and lower segments of small intestines from rat fetuses with surgically-induced obstruction (n = 14; ligature at ED18). The gene expression pattern was confirmed by immunohistochemistry, electron microscopy and RT-qPCR.

RESULTS

From ED15 to ED21, there was a physiological decrease in the gene expression of ENS markers and an increase in that of neuroendocrine genes. Regarding operated embryos, the changes in global gene expression were significantly higher in the proximal segment compared to the distal segment (18% vs. 9%). More precisely, a decrease in ENS gene expression and an increase in neuroendocrine gene expression were observed in the proximal segment compared to controls, indicating an accelerated maturation pattern. Immunohistochemistry and electron microscopy confirmed these findings.

CONCLUSION

Fetal intestinal obstruction seems to induce an accelerated maturation in the proximal segment. Moreover, neuroendocrine cells undergo significant unexpected changes, suggesting that ENS changes could be associated with other changes to induce intestinal motility disorders.

Changes of smooth muscle contractile filaments in small bowel atresia

AIM: To investigate morphological changes of intestinal smooth muscle contractile fibres in small bowel atresia patients.

METHODS: Resected small bowel specimens from small bowel atresia patients (n = 12) were divided into three sections (proximal, atretic and distal). Standard histology hematoxylin-eosin staining and enzyme immunohistochemistry was performed to visualize smooth muscle contractile markers α-smooth muscle actin (SMA) and desmin using conventional paraffin sections of the proximal and distal bowel. Small bowel from age-matched patients (n = 2) undergoing Meckel’s diverticulum resection served as controls.

RESULTS: The smooth muscle coat in the proximal bowel of small bowel atresia patients was thickened compared with control tissue, but the distal bowel was unchanged. Expression of smooth muscle contractile fibres SMA and desmin within the proximal bowel was slightly reduced compared with the distal bowel and control tissue. There were no major differences in the architecture of the smooth muscle within the proximal bowel and the distal bowel. The proximal and distal bowel in small bowel atresia patients revealed only minimal differences regarding smooth muscle morphology and the presence of smooth muscle contractile filament markers.

CONCLUSION: Changes in smooth muscle contractile filaments do not appear to play a major role in postoperative motility disorders in small bowel atresia.

Medical management of motility disorders in patients with intestinal failure: a focus on necrotizing enterocolitis, gastroschisis, and intestinal atresia

BACKGROUND

Intestinal failure (IF) is the dependence upon parenteral nutrition to maintain minimal energy requirements for growth and development. It may occur secondary to a loss of bowel length, disorders of motility, or both. Short bowel syndrome (SBS) is a malabsorptive state resulting from surgical resection, congenital defect, or diseases associated with loss of absorptive surface area. A particularly vexing problem is associated with whole bowel and/or segmental intestinal dysmotility. Motility disorders within the context of SBS and IF may relate to rapid intestinal transit secondary to loss of intestinal length, dysmotility associated with loss or poor antegrade peristalsis, or gastroparesis. Therapy may be classified into medical (prokinetic and antidiarrheal agents) and surgical to deal with the overdistended poorly motile bowel.

METHODS

We performed a systematic review of the literature pertaining to IF, SBS, and dysmotility in the pediatric population with gastroschisis, necrotizing enterocolitis, and intestinal atresia. In addition to the available treatment options, we have provided a review of the literature and a summary of the available evidence.

CONCLUSION

Despite relatively poor level of evidence regarding the application of promotility and antidiarrheal medications in patients with SBS and IF, these agents continue to be used. Herein, we provide a review of the physiology and pathophysiology of intestinal motility/dysmotility and available strategies for the use of promotility and antidiarrheal agents in patients with IF/SBS.

Differential changes in intrinsic innervation and interstitial cells of Cajal in small bowel atresia in newborns

AIM

To investigate morphological changes of the enteric nervous system (ENS) and the interstitial cells of Cajal (ICCs) in small bowel atresia.

METHODS

Resected small bowel specimens from affected patients (n = 7) were divided into three parts (proximal, atretic, distal). Standard histology and enzyme immunohistochemistry anti-S100, anti-protein gene product (PGP) 9.5, anti-neurofilament (NF), anti-c-kit-receptor (CD117) was carried out on conventional paraffin sections of the proximal and distal part.

RESULTS

The neuronal and glial markers (PGP 9.5, NF, S-100) were expressed in hypertrophied ganglia and nerve fibres within the myenteric and submucosal plexuses. Furthermore, the submucous plexus contained typical giant ganglia. The innervation pattern of the proximal bowel resembled intestinal neuronal dysplasia. The density of myenteric ICCs was clearly reduced in the proximal bowel, whereas a moderate number of muscular ICCs were found. The anti-CD117 immunoreaction revealed additional numerous mast cells. The distal bowel demonstrated normal morphology and density of the ENS, the ICCs and the mast cells.

CONCLUSION

The proximal and distal bowel in small bowel atresia revealed clear changes in morphology and density of the ENS and ICCs.

Pathological feature of a giant ileal Meckel's diverticulum with ectopic gastric mucosa

The ileum generally works well, whereas Meckel's diverticulum (MD) has complications including bleeding, obstruction, intussusception, diverticulitis, and perforation. Our knowledge of the pathological features of the MD muscular layer and mucosa is limited. We report a rare case of giant MD that was diagnosed by double-balloon enteroscopy (DBE). The pathological features of the mucosa were evaluated by investigation for Helicobacter pylori; and the nuclear proliferation antigen Ki-67, the gastrointestinal cancer-associated biomarker TRAK1, synaptophysin, and neurofilament were used to precisely define the mucosa and neuronal and ganglion cell components. The pathophysiology of MD is discussed and a literature review is presented. We believe that this is the first report of a systematic histochemical analysis of the mucosa and myenteric plexus of MD and the normal ileum. The present investigation may provide novel evidence of pathological abnormalities resulting in the complex complications of MD.