Structure of the myenteric plexus in normal and diseased human ileum analyzed by X-ray virtual histology slices.

BACKGROUND: The enteric nervous system (ENS) is situated along the entire gastrointestinal tract and is divided into myenteric and submucosal plexuses in the small and large intestines. The ENS consists of neurons, glial cells, and nerves assembled into ganglia, surrounded by telocytes, interstitial cells of Cajal, and connective tissue. Owing to the complex spatial organization of several interconnections with nerve fascicles, the ENS is difficult to examine in conventional histological sections of 3-5 µm. AIM: To examine human ileum full-thickness biopsies using X-ray phase-contrast nanotomography without prior staining to visualize the ENS. METHODS: Six patients were diagnosed with gastrointestinal dysmotility and neuropathy based on routine clinical and histopathological examinations. As controls, full-thickness biopsies were collected from healthy resection ileal regions after hemicolectomy for right colon malignancy. From the paraffin blocks, 4-µm thick sections were prepared and stained with hematoxylin and eosin for localization of the myenteric ganglia under a light microscope. A 1-mm punch biopsy (up to 1 cm in length) centered on the myenteric plexus was taken and placed into a Kapton® tube for mounting in the subsequent investigation. X-ray phase-contrast tomography was performed using two custom-designed laboratory setups with micrometer resolution for overview scanning. Subsequently, selected regions of interest were scanned at a synchrotron-based end-station, and high-resolution slices were reported. In total, more than 6000 virtual slices were analyzed from nine samples. RESULTS: In the overview scans, the general architecture and quality of the samples were studied, and the myenteric plexus was localized. High-resolution scans revealed details, including the ganglia, interganglional nerve fascicles, and surrounding tissue. The ganglia were irregular in shape and contained neurons and glial cells. Spindle-shaped cells with very thin cellular projections could be observed on the surface of the ganglia, which appeared to build a network. In the patients, there were no alterations in the general architecture of the myenteric ganglia. Nevertheless, several pathological changes were observed, including vacuolar degeneration, autophagic activity, the appearance of sequestosomes, chromatolysis, and apoptosis. Furthermore, possible expulsion of pyknotic neurons and defects in the covering cellular network could be observed in serial slices. These changes partly corresponded to previous light microscopy findings. CONCLUSION: The analysis of serial virtual slices could provide new information that cannot be obtained by classical light microscopy. The advantages, disadvantages, and future possibilities of this method are also discussed.

3d phase-contrast nanotomography of unstained human skin biopsies may identify morphological differences in the dermis and epidermis between subjects.

BACKGROUND: Enteric neuropathy is described in most patients with gastrointestinal dysmotility and may be found together with reduced intraepidermal nerve fiber density (IENFD). The aim of this pilot study was to assess whether three-dimensional (3d) imaging of skin biopsies could be used to examine various tissue components in patients with gastrointestinal dysmotility. MATERIAL AND METHODS: Four dysmotility patients of different etiology and two healthy volunteers were included. From each subject, two 3-mm punch skin biopsies were stained with antibodies against protein gene product 9.5 or evaluated as a whole with two X-ray phase-contrast computed tomography (CT) setups, a laboratory µCT setup and a dedicated synchrotron radiation nanoCT end-station. RESULTS: Two patients had reduced IENFD, and two normal IENFD, compared with controls. µCT and X-ray phase-contrast holographic nanotomography scanned whole tissue specimens, with optional high-resolution scans revealing delicate structures, without differentiation of various fibers and cells. Irregular architecture of dermal fibers was observed in the patient with Ehlers-Danlos syndrome and the patient with idiopathic dysmotility showed an abundance of mesenchymal ground substance. CONCLUSIONS: 3d phase-contrast tomographic imaging may be useful to illustrate traits of connective tissue dysfunction in various organs and to demonstrate whether disorganized dermal fibers could explain organ dysfunction.

3D analysis of the myenteric plexus of the human bowel by X-ray phase-contrast tomography - a future method?

OBJECTIVES: Light microscopical analysis in two dimensions, combined with immunohistochemistry, is presently the gold standard to describe the enteric nervous system (ENS). Our aim was to assess the usefulness of three-dimensional (3D) imaging by X-ray phase-contrast tomography in evaluating the ENS of the human bowel. MATERIAL AND METHODS: Myenteric ganglia were identified in full-thickness biopsies of the ileum and colon by hematoxylin & eosin staining. A1-mm biopsy punch was taken from the paraffin blocks and placed into a Kapton® tube for subsequent tomographic investigation. The samples were scanned, without further preparation, using phase-contrast tomography at two different scales: overview scans (performed with laboratory setups), which allowed localization of the nervous tissue (∼1µm effective voxel size); and high-resolution scans (performed with a synchrotron endstation), which imaged localized regions of 320x320x320 µm3 (176 nm effective voxel size). RESULTS: The contrast allowed us to follow the shape and the size changes of the ganglia, as well as to study their cellular components together with the cells and cellular projections of the periganglional space. Furthermore, it was possible to show the 3D network of the myenteric plexus and to quantify its volume within the samples. CONCLUSIONS: Phase-contrast X-ray tomography can be applied for volume analyses of the human ENS and to study tissue components in unstained paraffin-embedded tissue biopsies. This technique could potentially be used to study disease mechanisms, and to compare healthy and diseased tissues in clinical research.

Autonomic and peripheral neuropathy with reduced intraepidermal nerve fiber density can be observed in patients with gastrointestinal dysmotility.

Neuropathy should be considered as a possible etiological factor in patients with severe gastrointestinal symptoms, without signs of disease on routine investigations. Examinations of the autonomic and peripheral nervous systems may be helpful to select the patients who should be investigated with full-thickness intestinal biopsy, and to give appropriate care.

Spatial relationship between telocytes, interstitial cells of Cajal and the enteric nervous system in the human ileum and colon.

Telocytes (TCs) are recently described interstitial cells, present in almost all human organs. Among many other functions, TCs regulate gastrointestinal motility together with the interstitial cells of Cajal (ICCs). TCs and ICCs have close localization in the human myenteric plexus; however, the exact spatial relationship cannot be clearly examined by previously applied double immunofluorescence/confocal microscopy. Data on TCs and submucosal ganglia and their relationship to intestinal nerves are scarce. The aim of the study was to analyse the spatial relationship among these components in the normal human ileum and colon with double CD34/CD117 and CD34/S100 immunohistochemistry and high-resolution light microscopy. TCs were found to almost completely encompass both myenteric and submucosal ganglia in ileum and colon. An incomplete monolayer of ICCs was localized between the TCs and the longitudinal muscle cells in ileum, whereas only scattered ICCs were present on both surfaces of the colonic myenteric ganglia. TC-telopodes were observed within colonic myenteric ganglia. TCs, but no ICCs, were present within and around the interganglionic nerve fascicles, submucosal nerves and mesenterial nerves, but were only observed along small nerves intramuscularly. These anatomic differences probably reflect the various roles of TCs and ICCs in the bowel function.

Endoscopic versus Laparoscopic Full-Thickness Biopsy in the Pathological Evaluation of the Enteric Nervous System.

A full-thickness biopsy of the bowel wall is required to evaluate the enteric nervous system. A patient with aggravating gastrointestinal symptoms underwent a laparoscopic full-thickness biopsy of the ileum and, 1 year later, an endoscopic full-thickness biopsy of the sigmoid colon. Both samples showed enteric neuropathy characterized by vacuolated and enlarged neurons. The length of the myenteric plexus was greater in the endoscopic (23 mm) compared to the laparoscopic (11 mm) biopsy, with fewer tissue artefacts in the endoscopic approach [corrected]. Clinical deterioration was paralleled by enteric neuropathy with an increase in the percentage of vacuolated and enlarged enteric neurons from 24 to 35%.

Endoscopic full-thickness biopsy, a novel method in the work up of complicated abdominal symptoms.

Gastrointestinal complaints without obvious organic causes confirmed by clinical laboratory analyses, endoscopy or radiology are often referred to functional entities. Irritable bowel syndrome (IBS) is the most common functional disorder in the gut. Careful examination of these patients may reveal other diagnoses of defined etiologies, e.g., enteric neuropathy, microscopic colitis, and primary Sjögre's syndrome. The present case describes a young patient with incapacitating gastrointestinal symptoms presumed to be IBS, who underwent endoscopic full-thickness biopsy in sigmoid colon. Histopathological examination revealed degenerative enteric neuropathy, possibly secondary to chronic ischemia.

Depletion of enteric gonadotropin-releasing hormone is found in a few patients suffering from severe gastrointestinal dysmotility.

OBJECTIVE: Many patients, especially women, suffer from severe gastrointestinal pain and dysmotility for several years without being diagnosed. Depletion of gonadotropin-releasing hormone (GnRH) in the enteric nervous system (ENS) has been described in some patients. The aim of this study was to examine the expression of GnRH in ENS and antibodies against GnRH in serum, in a dysmotility patient cohort of southern Sweden. MATERIALS AND METHODS: All consecutive patients (n = 35) referred for laparoscopic full-thickness biopsy because of symptoms or signs of severe dysmotility between 1998 and 2009, or patients with a severe dysmotility disorder having had a bowel resection within the time frame, were considered for inclusion. In 22 cases, representative biopsy material containing ganglia was available, and these patients were included. Medical records were scrutinized. The expression of GnRH was determined by immunohistochemistry in bowel biopsies from these patients and in patients with carcinoma or diverticulosis without ENS histopathology. Antibodies against GnRH in serum were determined by ELISA in patients and controls. RESULTS: 14 patients were diagnosed with enteric dysmotility (ED) and 8 with chronic intestinal pseudo-obstruction due to varying etiology. Immunostained biopsies showed expression of GnRH in the ENS. A reduced expression of GnRH-containing neurons was found in 5 patients, as well as antibodies against GnRH in serum. 3 of these patients had a history of in vitro fertilization (IVF) using GnRH analogs. CONCLUSIONS: A subgroup of patients with severe dysmotility had a reduced expression of GnRH-containing neurons in the ENS and expressed antibodies against GnRH in serum.

Expression of Luteinizing Hormone Receptor in the Gastrointestinal Tract in Patients with and without Dysmotility.

Leuprolide is a gonadotropin-releasing hormone (GnRH) analog which has been shown to reduce symptoms in patients with irritable bowel syndrome (IBS) and chronic intestinal pseudo-obstruction (CIPO). The mechanism is not known, but one hypothesis is through down-modulation of luteinizing hormone (LH) secretion, a hormone whith antagonistic effect on gastrointestinal motility. However, presence of LH receptors in the gastrointestinal tract has never been described. The aim of this study was to find one possible way of action for leuprolide by examining the presence of the LH receptor, and if present, to see whether there was different expression in patients with or without dysmotility. Full-thickness biopsies from the bowel wall of patients with and without severe dysmotility were examined using immunohistochemistry staining. Biopsies showed expression of LH receptors on myenteric neurons and in glial cells, neutrophils, endothelial cells and mast cells. There was no difference in expression between patient groups.

The London Classification of gastrointestinal neuromuscular pathology: report on behalf of the Gastro 2009 International Working Group.

OBJECTIVE: Guidelines on histopathological techniques and reporting for adult and paediatric gastrointestinal neuromuscular pathology have been produced recently by an international working group (IWG). These addressed the important but relatively neglected areas of histopathological practice of the general pathologist, including suction rectal biopsy and full-thickness intestinal tissue. Recommendations were presented for the indications, safe acquisition of tissue, histological techniques, reporting and referral of such histological material. DESIGN: Consensual processes undertaken by the IWG and following established guideline decision group methodologies. RESULTS AND CONCLUSION: This report presents a contemporary and structured classification of gastrointestinal neuromuscular pathology based on defined histopathological criteria derived from the existing guidelines. In recognition of its origins and first presentation in London at the World Congress of Gastroenterology 2009, this has been named 'The London Classification'. The implementation of this classification should allow some diagnostic standardisation, but should necessarily be viewed as a starting point for future modification as new data become available.

Antibodies against gonadotropin-releasing hormone (GnRH) and destruction of enteric neurons in 3 patients suffering from gastrointestinal dysfunction.

BACKGROUND: Antibodies against gonadotropin-releasing hormone (GnRH) and gastrointestinal dysmotility have been found after treatment with GnRH analogues. The aim of this study was to examine the presence of such antibodies in patients with dysmotility not subjected to GnRH treatment and study the anti-GnRH antibody effect on enteric neurons viability in vitro. METHODS: Plasma and sera from 3 patients suffering from either enteric dysmotility, irritable bowel syndrome (IBS) or gastroparesis were analysed for C-reactive protein (CRP), and for GnRH antibodies and soluble CD40 by ELISA methods. Primary cultures of small intestinal myenteric neurons were prepared from rats. Neuronal survival was determined after the addition of sera either from the patients with dysmotility, from healthy blood donors, antiserum raised against GnRH or the GnRH analogue buserelin. Only for case 1 a full-thickness bowel wall biopsy was available for immunohistochemical analysis. RESULTS: All 3 patients expressed antibodies against GnRH. The antibody titer correlated to the levels of CD40 (rs = 1.000, p < 0.01), but not to CRP. Serum from case 3 with highest anti-GnRH antibody titer, and serum concentrations of sCD40 and CRP, when added to cultured rat myenteric neurons caused remarkable cell death. In contrast, serum from cases 1 and 2 having lower anti-GnRH antibody titer and lower sCD40 levels had no significant effect. Importantly, commercial antibodies against GnRH showed no effect on neuron viability whereas buserelin exerted a protective effect. The full-thickness biopsy from the bowel wall of case 1 showed ganglioneuritis and decrease of GnRH and GnRH receptor. CONCLUSION: Autoantibodies against GnRH can be detected independently on treatment of GnRH analogue. Whether the generation of the antibody is directly linked to neuron degeneration and chronic gastrointestinal symptoms in patients with intestinal dysmotility, remains to be answered.

Chlamydia trachomatis antigens in enteroendocrine cells and macrophages of the small bowel in patients with severe irritable bowel syndrome.

BACKGROUND: Inflammation and immune activation have repeatedly been suggested as pathogentic factors in irritable bowel syndrome (IBS). The driving force for immune activation in IBS remains unknown. The aim of our study was to find out if the obligate intracellular pathogen Chlamydia could be involved in the pathogenesis of IBS. METHODS: We studied 65 patients (61 females) with IBS and 42 (29 females) healthy controls in which IBS had been excluded. Full thickness biopsies from the jejunum and mucosa biopsies from the duodenum and the jejunum were stained with a monoclonal antibody to Chlamydia lipopolysaccharide (LPS) and species-specific monoclonal antibodies to C. trachomatis and C. pneumoniae. We used polyclonal antibodies to chromogranin A, CD68, CD11c, and CD117 to identify enteroendocrine cells, macrophages, dendritic, and mast cells, respectively. RESULTS: Chlamydia LPS was present in 89% of patients with IBS, but in only 14% of healthy controls (p < 0.001) and 79% of LPS-positive biopsies were also positive for C. trachomatis major outer membrane protein (MOMP). Staining for C. pneumoniae was negative in both patients and controls. Chlamydia LPS was detected in enteroendocrine cells of the mucosa in 90% of positive biopsies and in subepithelial macrophages in 69% of biopsies. Biopsies taken at different time points in 19 patients revealed persistence of Chlamydia LPS up to 11 years. The odds ratio for the association of Chlamydia LPS with presence of IBS (43.1; 95% CI: 13.2-140.7) is much higher than any previously described pathogenetic marker in IBS. CONCLUSIONS: We found C. trachomatis antigens in enteroendocrine cells and macrophages in the small bowel mucosa of patients with IBS. Further studies are required to clarify if the presence of such antigens has a role in the pathogenesis of IBS.

Intestinal lymphocytic epithelioganglionitis: a unique combination of inflammation in bowel dysmotility: a histopathological and immunohistochemical analysis of 28 cases.

AIMS: Visceral inflammatory neuropathies are enteric disorders underlying various forms of bowel dysmotility. The aim was to analyse the microscopic characteristics of a unique combination of intraepithelial lymphocytosis and myenteric ganglioneuritis. METHODS AND RESULTS: Paraffin sections of full-thickness proximal jejunal biopsy specimens from 28 patients, with proven disorders of gastrointestinal motility, were analysed following conventional and immunohistochemical staining. Serial transversal and tangential sectioning visualized large myenteric plexus areas. Between 1993 and 2005, 28 patients with inflammatory neuropathy (25 female and three male) showed this combination of lymphocytic infiltration. Two of the patients also had coeliac disease. The mean number of intraepithelial CD3+ lymphocytes was 36 per 100 epithelial cells (range 27-68; upper normal limit 25 lymphocytes). There was myenteric ganglionitis of variable severity (mean 4.6 myenteric lymphocytes per ganglion; upper normal limit two lymphocytes) with cytotoxic T-cell predominance. Myenteric neurons showed signs of degeneration and an abnormal immunohistological pattern. Hyperplasia and hypertrophy of Cajal cells were observed. The longitudinal muscle layer was thickened in many cases. CONCLUSIONS: A subset of patients with gastrointestinal motility disorders exhibit the combination of intraepithelial lymphocytosis and myenteric ganglionitis in full thickness biopsy specimens of the small bowel. We suggest calling this entity 'intestinal lymphocytic epithelioganglionitis'.

Gastrointestinal neuromuscular pathology: guidelines for histological techniques and reporting on behalf of the Gastro 2009 International Working Group.

The term gastrointestinal neuromuscular disease describes a clinically heterogeneous group of disorders of children and adults in which symptoms are presumed or proven to arise as a result of neuromuscular, including interstitial cell of Cajal, dysfunction. Such disorders commonly have impaired motor activity, i.e. slowed or obstructed transit with radiological evidence of transient or persistent visceral dilatation. Whilst sensorimotor abnormalities have been demonstrated by a variety of methods in these conditions, standards for histopathological reporting remain relatively neglected. Significant differences in methodologies and expertise continue to confound the reliable delineation of normality and specificity of particular pathological changes for disease. Such issues require urgent clarification to standardize acquisition and handling of tissue specimens, interpretation of findings and make informed decisions on risk-benefit of full-thickness tissue biopsy of bowel or other diagnostic procedures. Such information will also allow increased certainty of diagnosis, facilitating factual discussion between patients and caregivers, as well as giving prognostic and therapeutic information. The following report, produced by an international working group, using established consensus methodology, presents proposed guidelines on histological techniques and reporting for adult and paediatric gastrointestinal neuromuscular pathology. The report addresses the main areas of histopathological practice as confronted by the pathologist, including suction rectal biopsy and full-thickness tissue obtained with diagnostic or therapeutic intent. For each, indications, safe acquisition of tissue, histological techniques, reporting and referral recommendations are presented.

Operational tolerance in nonvascularized transplant models induced by AR-C117977, a monocarboxylate transporter inhibitor.

AR-C117977, a monocarboxylate transporter inhibitor, reduces immune responses both in vitro and in vivo, maintains long-term graft survival, and induces operational tolerance. To evaluate the immunosuppressive limitations of AR-C117977, this study was performed in nonvascularized transplant models noted for their refractive response to standard immunosuppressive agents. Rat skin was transplanted from DA(RT1avl) into PVG(RT1c) and the reverse. Mouse islet allotransplantation was performed with BALB/c H2d donors and C57Bl/6J H2b recipients. In the skin graft model, AR-C117977 monotherapy was associated with long-term skin graft survival in one rat strain combination. AR-C117977 and cyclosporine A (CsA) in combination resulted in significant prolongation of graft survival in both rat strains. CsA monotherapy did not prevent acute rejection in either strain. Islet allograft survival was moderately prolonged with CsA or AR-C117977. AR-C117977 is an efficient immunosuppressive drug in stringent rodent transplant models and further studies are warranted.

Dietary supplementation with carbonate increases expression of ornithine decarboxylase and proliferation in gastric mucosa in a rat model of gastric cancer.

Dietary factors play essential roles in gastric carcinogenesis. We recently found that dietary supplementation with NaHCO(3) significantly increased the development of gastric cancer in a rat gastric stump model. Here, we analysed nontransformed gastric mucosa for expression of the cancer-related proteins cyclooxygenase-2 (COX-2) and ornithine decarboxylase (ODC), and we examined the relationship between expression levels of those proteins and mucosal proliferation. Research has shown that COX-2 is upregulated in gastric mucosal inflammation and is strongly associated with gastrointestinal cancer. ODC is the key enzyme in polyamine synthesis and a regulator of cell proliferation. We performed gastric resections on 48 Wistar rats to induce spontaneous gastric cancer; half of these animals were given a normal diet, and the other half received a diet supplemented with NaHCO(3). Twenty-four unoperated rats served as a control group. The surgical procedure per se led to a significant rise in mucosal expression of COX-2 and an associated increase in cell proliferation. However, the COX-2 level in gastric mucosa was not further affected by dietary supplementation of carbonate. Interestingly, nontransformed gastric mucosa in the operated rats receiving a carbonate-supplemented diet showed a pronounced increase in ODC expression that was strongly correlated with a further enhanced cell proliferation. These results indicate that carbonate ions, which represent a major constituent of intestinal reflux into the stomach, increase the expression of ODC and thereby enhance cell proliferation in nontransformed mucosa, and consequently elevate the risk of gastric cancer.

The specific monocarboxylate transporter-1 (MCT-1) inhibitor, AR-C117977, induces donor-specific suppression, reducing acute and chronic allograft rejection in the rat.

BACKGROUND: In a search for immunosuppressive drugs having novel mechanisms, monocarboxylate transporter (MCT-1) inhibitors were identified that markedly inhibited immune responses. Here, we report the effects of AR-C117977, a potent MCT-1 inhibitor, on alloimmune responses in the rat. METHODS: In vitro activity was determined in a rat mixed lymphocyte response (MLR). In vivo activity was tested in a graft versus host response (GVHR) and in both high (DA to PVG) and low (PVG to DA) responder cardiac allograft models. To assess induction of donor-specific suppression recipients of allogeneic hearts surviving longer than 100 days received a second transplant either of the same donor strain or a third-party donor strain. Effects on chronic graft rejection were assessed histologically by evaluating vasculopathy in long-term surviving grafts and in an obliterative bronchiolitis (OB) model. RESULTS: AR-C117977 inhibited the rat MLR and was more potent than cyclosporin A (CsA). In the rat GVHR model, AR-C117977 gave a dose-related inhibition. In the high responder cardiac allograft model, graft survival in excess of 100 days was achieved with AR-C117977 compared with 20 days with CsA and all the long-term survivors exhibited donor-specific suppression on retransplantation. In the low responder model, both AR-C117977 and CsA induced survival in excess of 100 days. Histology of the long-term surviving grafts suggested reduced vasculopathy associated with chronic rejection. Furthermore, AR-C117977 inhibited the occlusion of transplanted trachea in a OB model. CONCLUSION: This report describes a MCT-1 specific inhibitor having immunosuppressive activity on alloimmune responses and inducing donor-specific suppression.