Intestinal Tunica Muscularis Research Articles

Two proteocephalid cestodes in the fish Malapterurus electricus and Heterobranchus bidorsalis from Lake Nasser, Egypt: a morphological, molecular, and histopathological study

Despite the importance of the electric catfish (Malapterurus electricus) and the African giant catfish (Heterobranchus bidorsalis) in the foodweb of Lake Nasser, Egypt, little is known about their diseases and parasitic fauna. This work describes, for the first time, cestodiasis in M. electricus and H. bidorsalis. Corallobothrium solidum and Proteocephalus sp. were identified morphologically and molecularly from M. electricus and H. bidorsalis, respectively. Using PCR, sequencing, and phylogenetic analysis, the two cestodes shared rRNA gene sequence similarities yet were unique and the two new sequences for the proteocephalid genera were submitted to the GenBank database. The prevalence of infection was 75% and 40% for the two fish species, respectively. Infections significantly increased in the summer and spring and were higher in female fish than in male fish. The intestine was the preferred site of the two adult cestodes. However, in the case of C. solidum some larval cestodes were found outside the intestine in between the skin and abdominal musculature, attached to the mesentery, and within intestinal tunica muscularis. Desquamation of the intestinal epithelium and inflammation at the site of infection in addition to congestion of the intestinal wall of the tapeworm infected fish were evident, indicating that C. solidum and Proteocephalus sp. impacted the infected fish. The larval stages of C. solidum attempted to penetrate the intestine and sometimes they were encircled within fibrous layers infiltrated with inflammatory cells. The infected fish’s musculature was free of cestode infections. Preventive measures should be implemented to prevent the spread of infections.

Leopold Auerbach's achievements in the field of vascular system.

The scientific activity of Leopold Auerbach (1828-1897) was associated with Wrocław (Brelsau) medical school, which was renowned for brilliant descriptors of cardiovascular system, whose world-famous achievements became eponymous in history of medicine. Such terms as plexus myentericus Auerbach and Friedreich-Auerbach disease are still used worldwide. Little is known about the fact that the vascular system was at least as important in his scientific impact as neuromuscular field. Actually, one could realize that ganglion cells, which were previously discovered in cardiac location, were identified by Auerbach at interface between circular and longitudinal layer of intestinal tunica muscularis proporia. Consequently, Auerbach focused closely on vessels after examination of neural and muscular components of selected parts of gastrointestinal tract. Namely, he noticed that tightly grouped cells that formed vessels in the process of vasculogenesis and angiogenesis to constitute the lining of capillaries, possessed nuclei.

Disruption of the pacemaker activity of interstitial cells of Cajal via nitric oxide contributes to postoperative ileus.

Interstitial cells of Cajal (ICC) serve as intestinal pacemakers. Postoperative ileus (POI) is a gastrointestinal motility disorder that occurs following abdominal surgery, which is caused by inflammation-induced dysfunction of smooth muscles and enteric neurons. However, the participation of ICC in POI is not well understood. In this study, we investigated the functional changes of ICC in a mouse model of POI. Intestinal manipulation (IM) was performed to induce POI. At 24h or 48h after IM, the field potential of the intestinal tunica muscularis was investigated. Tissues were also examined by immunohistochemistry and electron microscopic analysis. Gastrointestinal transit was significantly decreased with intestinal tunica muscularis inflammation at 24h after IM, which was ameliorated at 48h after IM. The generation and propagation of pacemaker potentials were disrupted at 24h after IM and recovered to the control level at 48h after IM. ICC networks, detected by c-Kit immunoreactivity, were remarkably disrupted at 24h after IM. Electron microscopic analysis revealed abnormal vacuoles in the ICC cytoplasm. Interestingly, the ICC networks recovered at 48h after IM. Administration of aminoguanidine, an inducible nitric oxide synthase inhibitor, suppressed the disruption of ICC networks. Ileal smooth muscle tissue cultured in the presence of nitric oxide donor, showed disrupted ICC networks. The generation and propagation of pacemaker potentials by ICC are disrupted via nitric oxide after IM, and this disruption may contribute to POI. When inflammation is ameliorated, ICC can recover their pacemaker function.

The Role of Enteric Glia Cells in Intestinal Regeneration After Mesenteric Ischemia and Reperfusion

Background: Acute occlusive mesenteric ischemia is a life-threatening disease and remains to be incompletely understood in modern gastrointestinal surgery. Recently it has been shown, that specifically enteric glia cells (EGCs) are important to maintain epithelial homeostasis in the intestine. After EGC ablation, lethal intestinal inflammation occurs. EGCs of various subtypes and locations interact with the gut microbiome, synthesize trophic factors (i.e. TGF-ß, GDNF) and potentially protect enteric neurons from I/R and oxidative stress. We hypothesize that EGC function may therefore be pivotal for regeneration of epithelial integrity, cell protection and recovery of intestinal function after I/R. EGC activation after intestinal ischemia and reperfusion (I/R) has been suggested, but the relevance of such a reactive “gliosis” in the intestine in analogy to an “astrocytosis” in the brain (i.e. after ischemic stroke) is not fully understood. We therefore aim to investigate the role of EGCs after I/R. Methods: We studied a superior mesenteric artery (SMA)-occlusion model in C57Bl/6 mice as well as in GFAP-GFP and GFAP-Td-Tomato reporter-mice, using the glial fibrillary acidic protein GFAP as an EGC marker. Anesthetized mice underwent median laparotomy and the SMA was identified and occluded with a microvascular clamp for 45 minutes. Intestinal samples were procured after 3 hours and 24 hours of reperfusion. To assess I/R injury, Parks’ score was performed in H/E stained paraffin slides and a standardized segment of ileum was tested for FITC dextran diffusion in an in-vitro assay confirming epithelial barrier breakdown. Immunofluorescence staining in intestinal whole mounts was performed for EGC markers. Intestinal samples were also analyzed for EGC related gene expression in the tunica muscularis. For further mechanistic studies, primary EGC cultures were established and subjected to in-vitro ischemic conditions. Results: Parks’ score showed a significant I/R injury in the intestines of SMA-clamped animals at both timepoints, concomitant to an epithelial barrier breakdown as tested in an in-vitro FITC dextran diffusion assay, compared to sham animals. Immunfluorescence staining of the EGC marker GFAP in intestinal tunica muscularis whole mounts showed a morphologic upregulation of GFAP filaments after 45 minutes of intestinal ischemia at 3h and 24h of reperfusion (mean fluorescence intensity MFI: clamp3h vs. sham3h and clamp24h vs. sham24; One Way Anova p<0.001). GFAP gene expression in the tunica muscularis of animals with SMA-clamping was significantly upregulated after 3h of reperfusion. Furthermore, in GFAP reporter mice (GFAP-GFP) gene expression of the well-established transcription factor and hypoxia marker HIF1-α was significantly upregulated after 3h and 24h of reperfusion (clamp3h vs. sham3h, unpaired t-test p<0.05; clamp24h vs. sham24h, unpaired t-test p<0.01), concomitantly to HIF1-α dependent genes such as TGFß1 and VEGF-α. It was also found, that several proinflammatory cytokines (IL-6, Il-1ß) and chemokines (MCP-1) were significantly upregulated after limited mesenteric ischemia both in the animal and in-vitro models.FigureFigureConclusion: Mesenteric ischemia and reperfusion activates GFAP-positive EGC potentially via HIF-1α dependent pathways and produces an inflammatory micro-environment. Further study of the interactions of EGC and the intestinal epithelium may provide new insights into the regenerative mechanisms of the bowel after limited mesenteric ischemia.

Idiopathic Fibrosis of the Tunica Muscularis of the Large Intestine in Five Horses with Colic

Histological evidence of fibrosis affecting the outer layer of the large intestinal tunica muscularis was identified in five of 32 horses affected by colic. In three cases, foci of pale eosinophilia and vacuolation of myocytes were observed. These findings are suggestive of a degenerative and fibrotic abnormality in the outer layer of the tunica muscularis of the large intestinal smooth muscle of some horses with colic.

Establishment of pacemaker activity in tissues allotransplanted with interstitial cells of Cajal

Loss or disruption of Kit(+) -interstitial cells of Cajal (ICC) capable of generating pacemaker activity has been implicated in the development of numerous gastrointestinal motility disorders. We sought to develop a model where ICC could be allotransplanted into intestines naturally devoid of these cells. Enzymatically dispersed cells from the intestinal tunica muscularis of Kit(+/copGFP) and Kit(V558Δ) /+ gain-of-function mice were allotransplanted into myenteric plexus regions of W/W(V) mutant intestines that lack ICC at the level of the myenteric plexus (ICC-MY) and pacemaker activity. Immunohistochemical analysis fate mapped the development of ICC-MY networks and intracellular microelectrode recordings provided evidence for the development of functional pacemaker activity. Kit(+) -ICC developed into distinct networks at the level of the myenteric plexus in organotypic cultures over 28days and displayed robust rhythmic pacemaker activity. This study demonstrates the feasibility of allotransplantation of ICC into the myenteric region of the small intestine and the establishment of functional pacemaker activity into tissues normally devoid of ICC-MY and slow waves, thus providing a possible basis for the therapeutic treatment of patients where ICC networks have been disrupted due to a variety of pathophysiological conditions.

Production of Short-chain Fatty Acids from Dietary Lactosucrose in the Hindgut and Its Effects on Digestive Organs of a Marine Teleost, Red Sea Bream Pagrus major

Gut microbes of red sea bream Pagrus major can ferment lactosucrose, an indigestible and fermentable oligosaccharide, in vitro. Dietar y lactosucrose (LS) increases mechanical strength of intestinal tunica muscularis of this fish. Thus, the aims of this study were to evaluate hindgut fermentation of dietary LS by the intra-luminal existence of short-chain fatty acids (SCFA), and to confirm the effect of this sugar on weight of digestive organs in a marine teleost, red sea bream. Fish of approximately 70g body weight were randomly assigned to two groups and fed either a commercial diet (control group) or a commercial diet supplemented with 0.24 g/100 g LS (LS group) for two months. Fish fed LS had greater SCFA in intestinal contents than did control fish (P< 0.001). The ratios of SCFA/total organic acids of hindgut contents exceeded 55% in fish fed LS and were significantly greater than in control fish (P< 0.01). Contents of free (not bonded) water in hindgut contents of fish fed LS were lower than in control fish (P< 0.05). Fish fed LS had heavier stomachs and intestines than in fish fed control diet (P< 0.05). The above results suggest that hindgut microbes of red sea bream can ferment LS to produce SCFA. Fermentation of this sugar should affect intestinal water absorption by lowering free water content and affect digestive organs by SCFA fermentation metabolites.

Fibrosing Gastrointestinal Leiomyositis as a Cause of Chronic Intestinal Pseudo-Obstruction in an 8-Month-Old Dog

An 8-month-old, female, mixed-breed dog presented to the Iowa State University Veterinary Teaching Hospital with a 1-month history of vomiting and diarrhea. An exploratory laparotomy was performed revealing markedly distended and fluid-filled small and large intestines that were not obstructed. The clinical condition of the dog did not improve subsequent to exploratory surgery, and it was euthanized. At necropsy, both the small and large intestines were distended (approximately 4 cm in diameter) and fluid-filled, and the wall was thin. The abdominal cavity contained approximately 500 ml of a brownish clear fluid. Microscopic lesions of the intestines were confined to the intestinal tunica muscularis and muscularis mucosae and consisted of locally extensive-to-diffuse replacement of the smooth muscle by fibrous tissue and multifocal infiltration by a moderately dense mononuclear inflammatory infiltrate. A unique finding was the presence of similar microscopic lesions in the tunica muscularis of the urinary bladder and stomach.

Ablation of connexin43 in smooth muscle cells of the mouse intestine: functional insights into physiology and morphology

Connexin43 (Cx43) gap-junction channels are highly abundant in intestinal smooth muscle but their functional impact has not been studied so far. Here, we have aimed to elucidate the functional role of Cx43 in the tunica muscularis of the mouse intestine in vivo. Transgenic mice with conditional deletion of Cx43 in smooth muscle cells (SMC) were generated. Histological investigations by immunofluorescence analyses and organ-bath recordings to assess the contractility of intestinal tissue strips were carried out. Measurements of gastrointestinal transit and of the visceromotor response by utilizing a standardized colorectal distension model to quantify alterations of visceral sensory function were also performed in SMC-specific Cx43 null mice and control littermates. Histologically, we found thickening of the tunica muscularis and a 13-fold increase of neutrophil infiltration of the gastrointestinal wall of SMC-specific Cx43 null mice. These animals also exhibited a decrease of 29% in gastrointestinal transit time. In contrast, the visceromotor response to a standardized colorectal distension was elevated, as was the contractility in SMC-specific Cx43 null mice, compared with controls. Thus, SMC-specific ablation of Cx43 in mice leads to morphological and functional alterations of the intestinal tunica muscularis, to gastrointestinal motor dysfunction and to altered visceral sensory function.

Differential in situ expression of the genes encoding the chemokines MCP-1 and RANTES in human inflammatory bowel disease.

Two chemotactic cytokines, monocyte chemoattractant protein-1 (MCP-1) and RANTES, possibly contribute to the recruitment and activation of leukocytes in inflamed tissues. The expression of these cytokine genes was evaluated in tissue sections from resected bowel segments of 14 patients with inflammatory bowel disease (IBD) and seven control patients by use of 35S-labelled antisense RNA probes. MCP-1 and RANTES transcripts were generally increased in the intestinal mucosa of patients with IBD, compared with controls. Whereas MCP-1 gene expression in the mucosa was restricted to the lamina propria, the gene coding for RANTES was expressed in intraepithelial lymphocytes and in the subepithelial lamina propria. Furthermore, MCP-1 mRNA, but not RANTES mRNA, was abundant in vessel-associated cells, such as endothelial cells, medial smooth muscle cells, and intraluminal cells; in smooth muscle cells of the intestinal tunica muscularis; and in cells of the myenteric plexus. Compared with controls, a significant increase of MCP-1-expressing cells was observed in tissue specimens from patients with IBD, in endothelial cells of venules, and in cells present in the lumen of intestinal vessels. Conversely, the expression of MCP-1 mRNA in smooth muscle cells and myenteric plexus cells appeared to be comparable in control and diseased intestines. The increased number of MCP-1 and RANTES mRNA-expressing cells in mucosa from patients with IBD suggests that these cytokines play a role in the pathogenesis of mucosal inflammation. Furthermore, the expression of the MCP-1 gene in vessel-associated cells may indicate its involvement in mechanisms regulating the adhesion of blood monocytes to endothelial cells.

Trophic effect of dietary lactosucrose on intestinal tunica muscularis and utilization of this sugar by gut microbes in red seabream Pagrus major, a marine carnivorous teleost, under artificial rearing

We examined the effects of dietary lactosucrose (20 mg · kg body mass −1 · day −1) on body mass gain and the thickness of intestinal tunica muscularis in artificially reared red seabream fed a commercial diet. Lactosucrose did not affect body mass gain. Fish fed lactosucrose had thicker and tougher intestinal tunica muscularis than control fish. In vitro batch culture of intestinal contents of these fish showed that gut fermentation exists in this marine carnivorous teleost. The fermentation can utilize lactosucrose as a substrate, at least in vitro.

Changes in intestinal tunica muscularis following dietary fiber feeding in rats

The morphological changes in the intestinal tunica muscularis induced by prolonged dietary fiber intake were determined in rat small intestine and colon with the aid of computerized image analysis. Thirty male Sprague-Dawley rats were fed either a fiber free, 15% cellulose or 15% pectin diet for 8 weeks. Intestine length was measured and stained cross sections of the jejunum, ileum, and colon were quantitated using image analysis. In the distal colon, muscle cell size was also determined. Despite lower weight gain in the pectin fed rats, both the small intestine and colon length were significantly increased. Cellulose feeding had a lesser effect on intestine length. Pectin fed rats had significantly increased relative tunica muscularis area (37.2 +/- 2.2 mm2) in ileum cross sections when compared to control (24.3 +/- 1.8 mm2) and cellulose fed rats (26.1 +/- 1.1 mm2). In the mid-colon, the tunica muscularis area was found to be pectin > cellulose > control (33.5 +/- 2.2; 29.7 +/- 1.7; 25.8 +/- 1.5 respectively) with significant differences reached between pectin and control rats. In jejunal samples, no differences were observed among the groups. Circular smooth muscle cell size in the distal colon was significantly increased following cellulose feeding but was less pronounced in the case of pectin. We conclude that fiber supplementation leads to morphological changes in the rat intestine including changes in length and tunica muscularis volume.

Sarcocysts in the Florida bobcat (Felis rufus floridanus).

Sarcocysts were found in the tongue, diaphragm, heart, intestinal tunica muscularis, and skeletal muscle of bobcats (Felis rufus floridanus) collected in Florida (USA). The tongue was found to be the best indicator tissue for sarcocysts (P less than 0.005). Thirty of 60 bobcats screened were found to contain sarcocysts in at least one of the muscle tissues examined. Of the positive bobcats, 28 of 28 tongues contained sarcocysts, while only 10 of 27 (37%), and 8 of 26 (31%) contained sarcocysts in the diaphragm or cardiac muscle, respectively. Although immune suppression has been suggested as a possible reason for formation of sarcocysts in some carnivores, no such correlation was evident in the bobcats. Comparisons of prey species taken by the panther and bobcat, and overlap of geographical range by the two species leave questions as to the source of infection, and the species of Sarcocystis that is infecting both felids.

Nematospiroides dubius: Mechanisms of host immunity : I. Parasite counts, histopathology, and serum transfer involving orally or subcutaneously sensitized mice

The immune response of mice sensitized to Nematospiroides dubius by 2 different procedures was studied. Worm counts, histopathology and serum transfers were employed as parameters of comparison between the 2 sensitization groups. The profile of the parasite elimination curve over 16 days postchallenge, was strikingly different for orally and subcutaneously sensitized mice. The precipitous reduction in parasite burden of the orally sensitized (OS) group was evident 24 hr after challenge, and was essentially completed by Day 7. Conversely, there was no significant reduction in the parasite population of subcutaneously sensitized (SS) mice until Day 3, and a considerable number of worms persisted in this group until Day 16, at which time both OS and SS animals had comparable levels of parasitism. Histopathologic observations of the small intestine revealed fewer active granulomatous lesions in OS mice when compared to their SS counterparts. However, the composition and size of the granulomas encapsulating the smaller histotropic larval stages were similar in both sensitization groups. In SS animals, large numbers of eosinophils were commonly observed enveloping medium sized worms in the intestinal tunica muscularis after Day 5. Serum transfer demonstrated the presence of growth suppressing antibody in the sera of both sensitization groups. In addition, significantly fewer worms could be recovered from OS serum recipients.

Nematospiroides dubius: Mechanisms of host immunity : II. Skin testing and immunosuppression of orally or subcutaneously sensitized mice

The present study was designed to acquire further understanding of the differences in the immune response of mice orally (OS) or subcutaneously (SS) sensitized to Nematospiroides dubius. Two immunosuppressive agents and skin tests were utilized in this regard. Rabbit antimouse thymus serum (RAMTS) and cyproheptadine (antihistamine-antiserotonin) were similarly effective in suppressing the immune response of subcutaneously sensitized mice. When compared to normal rabbit serum and SS control (sensitized, untreated) animals, observations of the intestinal tunica muscularis in the immunosuppressed SS groups revealed granulomatous lesions in which fewer eosinophils enveloped the sequestered parasite. Cyproheptadine was more successful than the other treatments in interrupting the immune expulsion of N. dubius from orally sensitized mice, but this was only at a borderline significance level. The size and intensity of the active cutaneous anaphylactic skin tests in OS mice injected with an adult or larval antigen, was greater than the response elicited in SS mice or uninfected control mice injected with the same preparations. Similarly, the reaction in subcutaneously sensitized mice exceeded that observed in the noninfected controls.