Effect of NSAIDs Supplementation on the PACAP-, SP- and GAL-Immunoreactive Neurons in the Porcine Jejunum.

Side effects associated with nonsteroidal anti-inflammatory drugs (NSAIDs) treatment are a serious limitation of their use in anti-inflammatory therapy. The negative effects of taking NSAIDs include abdominal pain, indigestion nausea as well as serious complications such as bleeding and perforation. The enteric nervous system is involved in regulation of gastrointestinal functions through the release of neurotransmitters. The present study was designed to determine, for the first time, the changes in pituitary adenylate cyclase-activating polypeptide (PACAP), substance P (SP) and galanin (GAL) expression in porcine jejunum after long-term treatment with aspirin, indomethacin and naproxen. The study was performed on 16 immature pigs. The animals were randomly divided into four experimental groups: control, aspirin, indomethacin and naproxen. Control animals were given empty gelatin capsules, while animals in the test groups received selected NSAIDs for 28 days. Next, animals from each group were euthanized. Frozen sections were prepared from collected jejunum and subjected to double immunofluorescence staining. NSAIDs supplementation caused a significant increase in the population of PACAP-, SP- and GAL-containing enteric neurons in the porcine jejunum. Our results suggest the participation of the selected neurotransmitters in regulatory processes of the gastrointestinal function and may indicate the direct toxic effect of NSAIDs on the ENS neurons.

Botulinum toxin as a treatment for short bowel syndrome in rats.

PURPOSE: The denervation of the intestine with benzalkonium chloride (BAC) reduces mortality and improves weight gain in rats with short bowel syndrome (SBS). Nevertheless, translating these promising findings from bench to bedside is not feasible because BAC promotes peritonitis and irreversible denervation which may be followed by an uncontrolled dilatation of the viscera. The use of botulinum toxin (BT) instead of BAC to achieve the denervation of the remaining small intestine in SBS could be an interesting option because it leads to a mild and transient denervation of the intestine. METHODS: Here we evaluated the effects of the ileal denervation with BT in rats with SBS by verifying the body weight variation and intestinal morphological parameters. Four groups with 6 animals each were submitted to enterectomy with an ileal injection of saline (group E) or BT (group EBT). Control groups were submitted to simulated surgery with an ileal injection of BT (group BT) or saline (group C - control). RESULTS: We observed that the treatment of the remaining ileum with BT completely reversed the weight loss associated to extensive small bowel resection. CONCLUSION: This may provide a new promising approach to the surgical treatment of SBS.

Interactions Between Commensal Bacteria and Enteric Neurons, via FPR1 Induction of ROS, Increase Gastrointestinal Motility in Mice.

BACKGROUND & AIMS: Reduced gastrointestinal (GI) motility is a feature of disorders associated with intestinal dysbiosis and loss of beneficial microbes. It is not clear how consumption of beneficial commensal microbes, marketed as probiotics, affects the enteric nervous system (ENS). We studied the effects of the widely used probiotic and the commensal Lactobacillus rhamnosus GG (LGG) on ENS and GI motility in mice. METHODS: Conventional and germ free C57B6 mice were gavaged with LGG and intestinal tissues were collected; changes in the enteric neuronal subtypes were assessed by real-time polymerase chain reaction, immunoblots, and immunostaining. Production of reactive oxygen species (ROS) in the jejunal myenteric plexi and phosphorylation (p) of mitogen-activated protein kinase 1 (MAPK1) in the enteric ganglia were assessed by immunoblots and immunostaining. Fluorescence in situ hybridization was performed on jejunal cryosections with probes to detect formyl peptide receptor 1 (FPR1). GI motility in conventional mice was assessed after daily gavage of LGG for 1 week. RESULTS: Feeding of LGG to mice stimulated myenteric production of ROS, increased levels of phosphorylated MAPK1, and increased expression of choline acetyl transferase by neurons (P < .001). These effects were not observed in mice given N-acetyl cysteine (a ROS inhibitor) or LGGΩSpaC (an adhesion-mutant strain of LGG) or FPR1-knockout mice. Gavage of mice with LGG for 1 week significantly increased stool frequency, reduced total GI transit time, and increased contractions of ileal circular muscle strips in ex vivo experiments (P < .05). CONCLUSIONS: Using mouse models, we found that LGG-mediated signaling in the ENS requires bacterial adhesion, redox mechanisms, and FPR1. This pathway might be activated to increase GI motility in patients.

Botulinum toxin as a treatment for short bowel syndrome in rats

Abstract Purpose: The denervation of the intestine with benzalkonium chloride (BAC) reduces mortality and improves weight gain in rats with short bowel syndrome (SBS). Nevertheless, translating these promising findings from bench to bedside is not feasible because BAC promotes peritonitis and irreversible denervation which may be followed by an uncontrolled dilatation of the viscera. The use of botulinum toxin (BT) instead of BAC to achieve the denervation of the remaining small intestine in SBS could be an interesting option because it leads to a mild and transient denervation of the intestine. Methods: Here we evaluated the effects of the ileal denervation with BT in rats with SBS by verifying the body weight variation and intestinal morphological parameters. Four groups with 6 animals each were submitted to enterectomy with an ileal injection of saline (group E) or BT (group EBT). Control groups were submitted to simulated surgery with an ileal injection of BT (group BT) or saline (group C - control). Results: We observed that the treatment of the remaining ileum with BT completely reversed the weight loss associated to extensive small bowel resection. Conclusion: This may provide a new promising approach to the surgical treatment of SBS.

Effect of absorption-modifying excipients, hypotonicity, and enteric neural activity in an in vivo model for small intestinal transport.

The small intestine mucosal barrier is physiologically regulated by the luminal conditions, where intestinal factors, such as diet and luminal tonicity, can affect mucosal permeability. The intestinal barrier may also be affected by absorption-modifying excipients (AME) in oral drug delivery systems. Currently, there is a gap in the understanding of how AMEs interact with the physiological regulation of intestinal electrolyte transport and fluid flux, and epithelial permeability. Therefore, the objective of this single-pass perfusion study in rat was to investigate the effect of three AMEs on the intestinal mucosal permeability at different luminal tonicities (100, 170, and 290 mOsm). The effect was also evaluated following luminal administration of a nicotinic receptor antagonist, mecamylamine, and after intravenous administration of a COX-2 inhibitor, parecoxib, both of which affect the enteric neural activity involved in physiological regulation of intestinal functions. The effect was evaluated by changes in intestinal lumen-to-blood transport of six model compounds, and blood-to-lumen clearance of 51Cr-EDTA (a mucosal barrier marker). Luminal hypotonicity alone increased the intestinal epithelial transport of 51Cr-EDTA. This effect was potentiated by two AMEs (SDS and caprate) and by parecoxib, while it was reduced by mecamylamine. Consequently, the impact of enteric neural activity and luminal conditions may affect nonclinical determinations of intestinal permeability. In vivo predictions based on animal intestinal perfusion models can be improved by considering these effects. The in vivo relevance can be increased by treating rats with a COX-2 inhibitor prior to surgery. This decreases the risk of surgery-induced ileus, which may affect the physiological regulation of mucosal permeability.

Imanaga's First Method for Reconstruction with Preservation of Mesojejunal Autonomic Nerves During Pylorus-Preserving Pancreatoduodenectomy.

BACKGROUND Pancreatic surgeries have undergone substantial development. Pancreaticoduodenectomy and pylorus-preserving pancreatoduodenectomy inherently require reconstruction. In 1960, Professor Imanaga introduced a reconstructive technique performed in the order of the gastric remnant, pancreatic duct, and biliary tree from the viewpoint of physiologic function after pancreaticoduodenectomy. We herein report our experience with Imanaga's first method during pylorus-preserving pancreatoduodenectomy and retrospectively evaluate the short- and long-term outcomes. Technicalities and pitfalls are also discussed. CASE REPORT Eight patients were evaluated (mean follow-up period, 16.7 ± 1.0 years). Mesojejunal autonomic nerves were preserved without tension to the greatest extent possible for reconstruction. Intentional dissection of regional lymph nodes and nerves was performed in five and two patients, respectively. During the short-term postoperative period, one patient developed pancreatic leakage resulting in an intraperitoneal abscess, and endoscopic transgastric drainage was required. Two patients developed delayed gastric emptying. In three patients, passage from the duodenojejunostomy to pancreaticojejunostomy was mechanically disturbed, and endoscopic dilations with a balloon bougie were repeated. Repeated cholangitis was observed in three patients. During the long-term postoperative period, neither cachexia nor sarcopenia was observed, although two patients had diabetes. Two patients were free from all medications. Three patients who did not undergo intentional dissection of lymph nodes and nerves showed acceptable short- and long-term outcomes, although one each developed repeated cholangitis and adhesive ileus during the short-term period. CONCLUSIONS Imanaga's first reconstruction may have potential benefits, especially for diseases that do not require intentional dissection. Adequate mobilization of the pancreatic remnant is important for successful reconstruction.

Small bowel capsule endoscopy revealing neuromuscular and vascular hamartoma of the jejunum: A case report.

RATIONALE: Digestive hemorrhage is a life-threatening and represents for both clinicians and patient a challenger problematic condition with the urgencies to discover the origin for correct the cause and safe the life of patient. PATIENT CONCERNS: We report the case of a 58 -year-old man with extremely rare hamartomatous neurovascular lesion. Following recurrent episode of intestinal hemorrhage the patient underwent small bowel capsule endoscopy. DIAGNOSES: Diagnosed with small intestine neoplasia. INTERVENTIONS: The patient underwent curative small bowel resection. Histologic diagnosis was neuromuscular and vascular hamartoma (NMVH). In the small intestine, neoplastic lesions are very rare (2%) and mostly malformative while the more frequent cause of cryptic digestive hemorrhage remains angiodysplasia (50%) . The preexisting NMVH was exacerbated by the use of non-steroidal anti-inflammatory drugs, causing hemorrhage due to diffuse ulceration. OUTCOMES: The patient stay healthy after treatment. LESSONS: This is an hemorrhagic lesion with macroscopic "neoplastic" patterns due to abnormal mixing of normal indigenous tissue components. It poses a diagnostic challenge for clinicians and pathologists, but diagnosis is facilitated by capsule endoscopy and surgical treatment should provide definitive resolution.

Toxoplasma gondii causes death and plastic alteration in the jejunal myenteric plexus.

AIM: To assess the effects of ME-49 Toxoplasma gondii (T. gondii) strain infection on the myenteric plexus and external muscle of the jejunum in rats. METHODS: Thirty rats were distributed into two groups: the control group (CG) (n = 15) received 1 mL of saline solution orally, and the infected group (IG) (n = 15) inoculated with 1 mL of saline solution containing 500 oocysts of M-49 T. gondii strain orally. After 36 d of infection, the rats were euthanized. Infection with T. gondii was confirmed by blood samples collected from all rats at the beginning and end of the experiment. The jejunum of five animals was removed and submitted to routine histological processing (paraffin) for analysis of external muscle thickness. The remaining jejunum from the others animals was used to analyze the general population and the NADH-diaphorase, VIPergic and nitrergic subpopulations of myenteric neurons; and the enteric glial cells (S100-IR). RESULTS: Serological analysis showed that animals from the IG were infected with the parasite. Hypertrophy affecting jejunal muscle thickness was observed in the IG rats (77.02 ± 42.71) in relation to the CG (51.40 ± 12.34), P < 0.05. In addition, 31.2% of the total number of myenteric neurons died (CG: 39839.3 ± 5362.3; IG: 26766.6 ± 2177.6; P < 0.05); hyperplasia of nitrergic myenteric neurons was observed (CG: 7959.0 ± 1290.4; IG: 10893.0 ± 1156.3; P < 0.05); general hypertrophy of the cell body in the remaining myenteric neurons was noted [CG: 232.5 (187.2-286.0); IG: 248.2 (204.4-293.0); P < 0.05]; hypertrophy of the smallest varicosities containing VIP neurotransmitter was seen (CG: 0.46 ± 0.10; IG: 0.80 ± 0.16; P < 0.05) and a reduction of 25.3% in enteric glia cells (CG: 12.64 ± 1.27; IG: 10.09 ± 2.10; P < 0.05) was observed in the infected rats. CONCLUSION: It was concluded that infection with oocysts of ME-49 T. gondii strain caused quantitative and plastic alterations in the myenteric plexus of the jejunum in rats.

Capsaicin alleviates abnormal intestinal motility through regulation of enteric motor neurons and MLCK activity: Relevance to intestinal motility disorders.

SCOPE: Capsaicin is an active component of chili peppers, having diverse effects. However, the effects of capsaicin on intestinal motility are still controversial. The present study aimed to investigate the effects of capsaicin on intestinal motility disorder and uncover related mechanisms. MATERIALS AND RESULTS: A rat model with intestinal motility disorder was established in vitro through adding different stimuli into tissue bath; in vivo using constipation and diarrhea model, respectively. Capsaicin exerted dual effects on intestinal motility, i.e. the relaxation and contraction of jejunum induced by corresponding stimulus were, respectively, regulated to be normal contraction by capsaicin. The mechanisms underlined capsaicin-induced dual effects were investigated using Western blotting, qRT-PCR, and whole-cell patch clamp, respectively. Results showed that cholinergic excitatory nerves, adrenergic nerves, and neurons containing nitric oxide synthase, which are the main muscle motor neurons in enteric nervous system (ENS), are involved in capsaicin-induced dual effects. The competition for regulation of Ca(2+) influx by capsaicin induced the interaction with components of the ENS. Capsaicin significantly increased myosin light chain kinase (MLCK) expression and myosin phosphorylation extent in jejunal segments of constipation-prominent rats and significantly decreased MLCK expression and myosin phosphorylation extent in jejunal segments of diarrhea-prominent rats. CONCLUSION: In summary, capsaicin alleviates abnormal intestinal motility through regulating enteric motor neurons and MLCK activity, which is beneficial for the treatment of gastrointestinal motility disorders.

Intestinal and neuronal myenteric adaptations in the small intestine induced by a high-fat diet in mice.

BACKGROUND: The prevalence of obesity has increased at alarming rates, particularly because of the increased consumption of high-fat diets (HFDs). The influence of HFDs on intrinsic innervation and the intestinal wall has not been fully characterized. The aim of this study was to investigate the morpho-quantitative aspects of myenteric neurons and the wall of the small intestine in mice fed a HFD. METHODS: Swiss mice were fed a HFD (59% kcal from fat) or standard chow (9% Kcal from fat) for 8 weeks. Segments of the duodenum, jejunum, and ileum were subjected to histological processing for morpho-quantitative examination of the intestinal wall and mucosal cells, and immunohistochemistry was performed to evaluate myenteric neurons. The data for each segment were compared between the groups using an unpaired Student's t-test or an equivalent nonparametric test. RESULTS: The HFD increased body weight and visceral fat and decreased the length of the small intestine and the circumference of the ileum. In the duodenum, the HFD increased the density of the nitrergic subpopulation and decreased the area of nitrergic neurons and vasoactive intestinal peptide (VIP) varicosities. In the jejunum, the density of the nitrergic subpopulation was increased and the neuronal areas of the general population, nitrergic subpopulation and (VIP) varicosities were reduced. In the ileum, the density of the general population and nitrergic subpopulation were increased and the neuronal areas of the general population, nitrergic subpopulation and (VIP) varicosities were reduced. The morphometric parameters of the villi, crypts, muscular layer and total wall generally increased in the duodenum and jejunum and decreased in the ileum. In the duodenum and jejunum, the HFD promoted a decreased in the proportion of intraepithelial lymphocytes. In the ileum, the proportion of intraepithelial lymphocytes and goblet cells reduced, and the enteroendocrine cells increased. CONCLUSIONS: The high-fat diet induces changes in the myenteric innervation of the small intestine, intestinal wall and mucosal cells responsible for the secretion of hormones and maintenance of the protective intestinal barrier. The morpho-quantitative data provide a basis for further studies to clarify the influence of HFD in the motility, digestive and absorptive capacity, and intestinal barrier.

Vasoactive intestinal peptide is a local mediator in a gut-brain neural axis activating intestinal gluconeogenesis.

Intestinal gluconeogenesis (IGN) promotes metabolic benefits through activation of a gut-brain neural axis. However, the local mediator activating gluconeogenic genes in the enterocytes remains unknown. We show that (i) vasoactive intestinal peptide (VIP) signaling through VPAC1 receptor activates the intestinal glucose-6-phosphatase gene in vivo, (ii) the activation of IGN by propionate is counteracted by VPAC1 antagonism, and (iii) VIP-positive intrinsic neurons in the submucosal plexus are increased under the action of propionate. These data support the role of VIP as a local neuromodulator released by intrinsic enteric neurons and responsible for the induction of IGN through a VPAC1 receptor-dependent mechanism in enterocytes.

Skin-derived precursors generate enteric-type neurons in aganglionic jejunum.

PURPOSE: Skin-derived precursor cells (SKPs) may regenerate the enteric nervous system in Hirschsprung's disease. SKPs migrate and differentiate into myenteric ganglia in aganglionic intestine. We sought to characterize the time-course of SKP gangliogenesis and enteric neurotransmitter synthesis in vivo. METHODS: Adult Lewis rat jejunal segments were isolated and denervated with benzalkonium chloride (BAC). Denervation was evaluated by immunohistochemical (IHC) stains for markers of mature neuronal and glial cells. Green fluorescent protein (GFP)-expressing neonatal rat SKPs were cultured in neuroglial-selective medium. SKPs were transplanted into aganglionic segments 65-85days after BAC treatment. IHC was performed to identify glia, neurons, and neurotransmitter synthesis in GFP+cells between post-transplant days 1 and 28. RESULTS: Aganglionosis was confirmed by IHC. On post-transplant days 1 and 2, GFP+cells were detected near injection sites within the muscularis propria. GFP+cell clusters were evident only between longitudinal and circular smooth muscle layers at post-transplant days 14, 21, and 28. These structures co-expressed markers of mature neurons and gliocytes. Several markers of neurotransmitter synthesis were detected in GFP+clusters at days 21 and 28. CONCLUSION: SKPs are capable of enteric neuroglial differentiation in vivo. SKPs migrate to the intermuscular layer of aganglionic intestine within days of transplantation. Our observations suggest that SKPs are capable of generating enteric ganglia in aganglionic intestine.

Effect of fumonisin-containing diet on the myenteric plexus of the jejunum in rats.

Fumonisins are mycotoxins that naturally occur as contaminants in grains that are destined for animal and human consumption. These mycotoxins cause hepatotoxic, nephrotoxic, carcinogenic, teratogenic, immunotoxic, and neurotoxic effects in different intensities based on dose, time of exposure, and animal species. In the present study, male Wistar rats were fed between postnatal days 21 and 63 with diets that contained fumonisins B1+B2 at concentrations of 1 and 3mg/kg. The objective of the present study was to evaluate the effects of fumonisins on food intake, growth, weight gain, serum activity of the alanine aminotransferase and aspartate aminotransferase enzymes, and quantitative and morphometric parameters of myenteric neurons in the jejunum that are immunoreactive to HuC/D protein and neuronal nitric oxide synthase enzyme (nNOS). Diets that contained fumonisins did not significantly alter food intake or body and blood parameters. We did not observe significant differences in the neuronal density and proportion of nitrergic neurons but found a significant reduction of cell body areas in both neuronal populations. This study is the first to report the effects of fumonisins in the enteric nervous system. The possible mechanisms by which fumonisins impair neuronal development and the use of the enteric nervous system as a tool for the study of the neurotoxic effects of fumonisins are discussed. In conclusion, fumonisin-containing food negatively affected the growth of myenteric neurons.

A novel in vivo model of permanent intestinal aganglionosis.

BACKGROUND: Enteric neuromuscular disease is a characteristic of several disease states, including Hirschsprung disease, esophageal achalasia, Chagas disease, and gastroparesis. Medical therapy for these conditions is limited, and surgical intervention may incur significant morbidity. Alternatively, transplantation of neural progenitor cells may regenerate enteric ganglia. Existing aganglionosis model systems are limited by swift animal demise or by spontaneous regeneration of native ganglia. We propose a novel protocol to induce permanent aganglionosis in a segment of rat jejunum, which may serve as an experimental transplantation target for cellular therapy. MATERIALS AND METHODS: This protocol was performed in 17 adult female Sprague-Dawley rats. A laparotomy was performed and a 1-cm segment of jejunum was isolated from continuity. Among 14 rats, the isolated segments were treated with benzalkonium chloride (BAC) for 20 min to induce aganglionosis. Jejunal segment isolation was performed without BAC treatment in three rats. The animals were euthanized at posttreatment days 21-166. Muscle layer diameter was compared among normal, isolated, and BAC-treated isolated jejunal segments. The presence of jejunal ganglia was documented by immunohistochemical staining (IHC) for beta-III tubulin (TUJ1) and S100, markers of neuronal and glial cell lineages, respectively. RESULTS: Ganglia were identified by IHC in normal and isolated jejunal segments. Isolated segments had significantly hypertrophied smooth muscle layers compared with normal jejunum (diameter 343 ± 53 µm versus 211 ± 37 µm, P < 0.0001). BAC-treated jejunal segments had no IHC evidence of ganglionic structures. Aganglionosis was persistent in all specimens up to 166 days after treatment. CONCLUSIONS: The exclusion of a jejunal segment from continuity and concurrent treatment with BAC results in an effective, reproducible, and permanent model of aganglionosis. Muscular hypertrophy and aganglionosis in the isolated jejunal segment make it an ideal recipient site for transplantation of neuroglial precursor cells.

Effects of ginsenoside Re on rat jejunal contractility.

Ginsenoside Re (GRe) exerts diverse effects. Based on our observations, the present study was designed to investigate GRe-exerted bidirectional regulation (BR) on the contractility of isolated jejunal segment. Six pairs of different low and high contractile states of rat jejunal segment were established and used in the study. Stimulatory effects on the contractility of jejunal segment were exerted by GRe (10.0 µM) in all 6 low contractile states, and inhibitory effects were exerted in all 6 high contractile states, indicating that GRe exerted BR on the contractility of jejunal segment. The effects of GRe on the phosphorylation of 20 kDa myosin light chain, protein contents of myosin light chain kinase (MLCK) and MLCK mRNA expression in jejunal segment in low and high contractile states were also bidirectional. GRe-exerted BR was abolished in the presence of neurotoxin tetrodotoxin or Ca2+ channel blocker verapamil or c-Kit receptor tyrosine kinase inhibitor imatinib. Atropine blocked the stimulatory effects of GRe on jejunal contractility in low-Ca2+-induced low contractile state; phentolamine, propranolol and l-NG-nitro-arginine blocked the inhibitory effects in high-Ca2+-induced high contractile state, respectively. In summary, GRe-exerted BR depends on jejunal contractile state and requires the presence of enteric nervous system, Ca2+, and interstitial cells of Cajal; the stimulatory effects of GRe on jejunal contractility are related to cholinergic stimulation and inhibitory effects are related to adrenergic activation and nitric oxide relaxing mechanisms.

VPAC1 receptors regulate intestinal secretion and muscle contractility by activating cholinergic neurons in guinea pig jejunum.

In the gastrointestinal tract, vasoactive intestinal peptide (VIP) is found exclusively within neurons. VIP regulates intestinal motility via neurally mediated and direct actions on smooth muscle and secretion by a direct mucosal action, and via actions on submucosal neurons. VIP acts via VPAC1 and VPAC2 receptors; however, the subtype involved in its neural actions is unclear. The neural roles of VIP and VPAC1 receptors (VPAC1R) were investigated in intestinal motility and secretion in guinea pig jejunum. Expression of VIP receptors across the jejunal layers was examined using RT-PCR. Submucosal and myenteric neurons expressing VIP receptor subtype VPAC1 and/or various neurochemical markers were identified immunohistochemically. Isotonic muscle contraction was measured in longitudinal muscle-myenteric plexus preparations. Electrogenic secretion across mucosa-submucosa preparations was measured in Ussing chambers by monitoring short-circuit current. Calretinin(+) excitatory longitudinal muscle motor neurons expressed VPAC1R. Most cholinergic submucosal neurons, notably NPY(+) secretomotor neurons, expressed VPAC1R. VIP (100 nM) induced longitudinal muscle contraction that was inhibited by TTX (1 µM), PG97-269 (VPAC1 antagonist; 1 µM), and hyoscine (10 µM), but not by hexamethonium (200 µM). VIP (50 nM)-evoked secretion was depressed by hyoscine or PG97-269 and involved a small TTX-sensitive component. PG97-269 and TTX combined did not further depress the VIP response observed in the presence of PG97-269 alone. We conclude that VIP stimulates ACh-mediated longitudinal muscle contraction via VPAC1R on cholinergic motor neurons. VIP induces Cl(-) secretion directly via epithelial VPAC1R and indirectly via VPAC1R on cholinergic secretomotor neurons. No evidence was obtained for involvement of other neural VIP receptors.

Spiral intestinal lengthening and tailoring - first in vivo study.

INTRODUCTION: Spiral Intestinal Lengthening and Tailoring (SILT) offers a new opportunity for the surgical treatment of short bowel syndrome. SILT requires less manipulation on the mesentery than the Bianchi procedure and does not alter the orientation of the muscle fibers like serial transverse enteroplasty (STEP). This study reports the first SILT results in a surviving animal model. MATERIAL AND METHODS: Vietnamese minipigs (n=6) underwent interposition of a reversed intestinal segment to produce proximal small bowel dilation. Five weeks later the reversed segment was resected, and the wall of the dilated intestine was cut spirally at 45°-60° to its longitudinal axis. The bowel was lengthened longitudinally, and the spiral shaped intestinal wound was sutured. Five weeks later, the animals were explored, and the lengthened segments were measured. Haematoxylin and eosin, picrosirius, neuron specific enolase, S-100, C-kit, and immunohistochemistry were performed. RESULTS: Mean lengthening was 74.8% ± 29.5% and mean tailoring (lumen reduction) was 56.25% ± 18.8%. No instances of necrosis, perforation, suture break down, or peritonitis were observed in 6/6 animals. Four of six animals recovered uneventfully with viable lengthened segments. Statistical analysis showed no significant difference in length (p=0,078) and width (p=0,182) after 5 weeks. Two animals developed bowel obstruction due to narrowed lumen, adhesion, and strangulation after 14 and 24 days of surgery. In both animals the lumen was tailored by more than 70% to less than 1.5 cm diameter. The mucosa and the muscle layers in the operated segment had become hypertrophic, but the orientation of the circular and longitudinal muscle fibres remained normal after the SILT procedure. There were no signs of chronic ischemia or collagen accumulation after the SILT. The myenteric and submucosal plexuses and the Cajal cell network appeared normal. CONCLUSION: The bowel remained viable macroscopically and microscopically after SILT, such that SILT may be an alternative or an addition to the present technical repertoire of intestinal lengthening. However the limitations of tailoring should be kept in mind.

Does different approach during pancreatoduodenectomy influence intestinal migrating myoelectrical complex recovery? Study in experimental pig model.

It is said that leaving intact the functional motor unit of the pylorus leads to better gastric emptying and reduces postoperative upper gut motility disturbances. However, despite obvious different surgical approach, both major pancreatoduodenectomies lead to substantial myoelectrical dysfunctions. The latter are not efficiently recognized. We compared Whipple and Longmire-Traverso procedures in terms of electromyography patterns of the upper jejunum musculature and the density of Cajal cells network. Twelve male weaned pigs underwent surgery first to implant bipolar electrodes and telemetry transmitters for continuous electromyography recordings and then, after 1 week recovery, to create Whipple (n=6) and Longmire-Traverso (n=6) pancreatoduodenectomies. The first myoelectric activity was already registered 1-2 hours after both operations. Time to first regular patterns of migrating myoelectrical complex activity was significantly longer in the Whipple than in the Longmire-Traverso group (68.2±12.9 versus 27.8±51 hours, p=0.002). However, the restored patterns were substantially disturbed in both groups. Namely, after Longmire-Traverso operation, migrating myoelectrical complex cycles were very often and significantly shorter versus control ones, with reverse migration in the area of anastomosis while after Whipple procedure migrating myoelectrical complex cycles were less frequent and of short duration, significantly shorter in comparison even with Longmire-Traverso group. Cajal cells network in the vicinity of anastomosis, and distally from it, presented greater destruction after the Whipple operation. In conclusion, the advantage of one of two major pancreatoduodenectomies in terms of myoelectrical activity correctness in upper gut has not been proved in the study.

P2X4 subunits are part of P2X native channels in murine myenteric neurons.

The aim of the present study was to investigate if P2X4 receptors are expressed in murine myenteric neurons and if these receptors contribute to form functional channels in the neuronal membrane by using molecular and electrophysiological techniques. The whole-cell recording technique was used to measure membrane currents induced by ATP (I(ATP)) in myenteric neurons. Compared with recombinant P2X4 receptor-channels (reported by others in a previous study), native myenteric P2X receptors have a relative lower sensitivity for ATP (EC50=102 µM) and α,ß methylene ATP (not effect at 30 or 100 µM). BzATP was a weak agonist for native P2X receptors. KN-62 had no effect on myenteric P2X channels whereas PPADS (IC50=0.54 µM) or suramin (IC50=134 µM) were more potent antagonists than on P2X4 homomeric channels. I(ATP) were potentiated by ivermectin (effect that is specific on P2X4 receptors) and zinc. Western blotting shows the presence of P2X4 protein and RT-PCR the corresponding mRNA transcript in the small intestine. Immunoreactivity for P2X4 receptors was found in most myenteric neurons in culture. Single-cell RT-PCR shows the presence of P2X4 mRNA in 90% of myenteric neurons. Our results indicate that P2X4 receptors are expressed in the majority of myenteric neurons, contribute to the membrane currents activated by ATP, and because most properties of I(ATP) does not correspond to P2X4 homomeric channels it is proposed that P2X4 are forming heteromeric channels in these neurons. P2X4 subunits have a widespread distribution within the myenteric plexus and would be expected to play an important role in cell signaling.

Regeneration of enteric ganglia in mechanically lengthened jejunum after restoration into intestinal continuity.

PURPOSE: We previously demonstrated that it is feasible to lengthen intestinal segments with mechanical force and to restore them back into intestinal continuity. The changes in the enteric ganglia in the lengthened intestinal segments have not been described. METHODS: A 1-cm segment of rodent jejunum was isolated from intestinal continuity and was lengthened using a spring. After lengthening, jejunal segments were either retrieved (n=4) or restored into intestinal continuity (n=4). Rats with restored segments were euthanized 2 to 3 weeks later. Ganglia were identified and quantified by immunostaining of histological sections. RESULTS: The normal jejunum had 51 ± 5 myenteric and 31 ± 2 submucosal ganglia per circumferential tissue section. Lengthened segments had 21 ± 7 myenteric and 2 ± 2 submucosal ganglia. Restored segments had 46 ± 14 myenteric and 10 ± 10 submucosal ganglia. Circumferential density of ganglia followed a similar pattern. CONCLUSION: Mechanical lengthening led to a paucity of submucosal and myenteric ganglia. After restoration into continuity, the number increased toward normal, indicating regeneration of the enteric ganglia. The function of regenerated ganglia needs to be assessed in the future.