Desmosis

Abstract: The peristaltic movement of the gut is a function of the alternating contraction and relaxation of circular and longitudinal muscles. This movement is induced by a tendon-like connective-tissue net (TCTN) in the circular and longitudinal muscles, which are both rooted in a connective-tissue plexus layer (CTPL). In children with a therapy-resistant aperistaltic or hypoperistaltic syndrome who had normally-developed enteric innervation, a lack of the TCTN in the muscularis propria was observed. Over the last 2 years, 241 children with chronic constipation were investigated histopathologically; 46 children surgically treated by partial resection of the gut or diagnostically investigated by whole-mount biopsy. Fifteen children had a hypoperistalsis syndrome and 3 had an aperistalsis syndrome. All specimens were native and cut in a cryostat. Enteric innervation was examined by acetylcholinesterase and dehydrogenase reactions. The TCTN in the muscularis propria was stained with picric acid/sirius red. In the children with an aperistalsis syndrome, a complete lack of the TCTN in circular and longitudinal muscles was observed. A CTPL was not developed. The children with a hypoperistalsis syndrome had no CTPL, but had a partly-developed TCTN in the circular and longitudinal muscles, which gradually faded in the direction of the plexus layer. Independent of a well-developed enteric nervous system, a lack of the TCTN in longitudinal and circular muscles and a missing CTPL (aplastic desmosis) abolishes the coordinated peristaltic movement of the gut. An isolated lack of the CTPL in the myenteric plexus (hypoplastic desmosis) results in a hypoperistalsis syndrome. An anomaly of the TCTN in the muscularis propria disturbs gut-muscle mechanics, and is another cause of gut dysmotility.

Abstract: Introduction Efficient intestinal peristalsis is a function of intact enteric nervous system, muscle, and connective muscularis propria tissue. Malfunction of any component results in impaired peristalsis. Hirschsprung disease (HD) as prototypic enteric neural migration disorder is increasingly well characterized. More recently, intestinal myopathiesandparticularlydefectsofmyentericcollagenizationhaveenteredthefocus of attention. However, detailed development of muscularis propria connective tissue is not well known. The aim of this study was to morphologically characterize intestinal connectivetissue infetal and postnatal development and intestinal pseudo-obstruction. Materials and Methods In this study, 130 archival specimens of fetal autopsies, intestinal resections, and biopsies were analyzed. Patients’ age was 10th gestational week (gw) to 70 years. Muscularis mucosae, muscle layers, collagen tissue, and enteric plexus were analyzed. Picrosirius red stains, enzyme histochemistry, and immunohistochemistry for collagens I, III, and IV were performed. Results Total 89 normal intestinal specimens were from fetal autopsies or intestinal resections; 41 patients showed a primary structural colon wall defect (HD, desmosis). Our results showed a constant increase in tunica muscularis propria thickness with age. Separation into circular and longitudinal muscle layer first occurred in the 11th gw. A tendinous collagen plexus layer first arose in the 10th gw and showed a steady caliber increase. Muscularis mucosae first appeared in the 10th gw and grew independent of any primary gastrointestinal disease. In the 11th gw, enteric ganglia were fully developed. In desmosis, a collagen plexus layer was absent. In contrast, in HD, muscularis mucosae showed hypertrophy, but the collagen plexus layer was intact in the aganglionic segment. In intestinal neuronal dysplasia and hypoganglionosis, nerve cell development was disturbed; connective tissue and muscle layers were well developed. Conclusion Our comprehensive study of intestinal connective tissue development in comparison to neural intestinal wall components in normal and pathological conditions showed that tendinous tissue develops parallel to muscularis propria and arises early in embryogenesis. In enteric nervous system disorders, ganglionic lesions develop

Abstract: Megacystis-microcolon intestinal hypoperistalsis syndrome (MMHIS or Berdon syndrome) is an autosomal-recessive disorder characterized by chronic intestinal obstruction. Although the disease is often diagnosed in female infants we describe a man with late diagnosis in adulthood. Our patient presented soon after birth with intestinal obstruction and developed short bowel syndrome after multiple intestinal resections. Of note, the connective tissue net within the muscle layers of the intestinal wall was absent ('aplastic desmosis'). This case illustrates the variable clinical features of MMHIS and aplastic desmosis, which might delay the correct diagnosis of a severe disorder.

Abstract: We present four patients 5, 10, 12, and 17 years of age, each with a long history of severe constipation and hypoperistalsis of the gut. Three had partial or total resection of the colon, all had enterostomies, and only one maintains normal bowel function after reanastomosis. We report the clinical courses, radiologic findings, and operative procedures for all four cases. Preoperative full-thickness biopsies and the resected colon specimens revealed a complete or incomplete lack of the mesh network of collagen. The connective-tissue layer between the circular and longitudinal muscles was missing. Contrary to expectations, the enteric nervous system (ENS) was normal or near-normal in the affected areas. Hypo- and dysganglionosis was found additionally in some proximal segments of colon and/or small bowel. This combination of clinical symptoms and pathological findings is called desmosis of the colon with referrence to a working hypothesis in a preliminary report by Meier-Ruge in 1998. Aplastic or hypoplastic desmosis may be the reason for the disturbed gut motility. Histologic examination should thus not only exclude changes of the ENS.