Endoscopic "no hole" full-thickness biopsy of the stomach to detect myenteric ganglia

Updates in the Field of Submucosal Endoscopy

Submucosal endoscopy (third-space endoscopy) can be defined as an endoscopic procedure performed in the submucosal space. This procedure is novel and has been utilized for delivery to the submucosal space in a variety of gastrointestinal diseases, such as a tumor, achalasia, gastroparesis, and subepithelial tumors. The main submucosal endoscopy includes peroral endoscopic myotomy, gastric peroral endoscopic myotomy, Zenker peroral endoscopic myotomy, submucosal tunneling for endoscopic resection, and endoscopic submucosal tunnel dissection. Submucosal endoscopy has been used as a viable alternative to surgical techniques because it is minimally invasive in the treatment and diagnosis of gastrointestinal diseases and disorders. However, there is limited evidence to prove this. This article reviews the current applications and evidence regarding submucosal endoscopy while exploring the possible future clinical applications in this field. As our understanding of these procedures improves, the future of submucosal endoscopy could be promising in the fields of diagnostic and therapeutic endoscopy.

Submucosal Tunneling Muscle Biopsy for Esophageal Motility Disorders: A Case Report

Submucosal tunneling endoscopic technique can be useful in obtaining esophageal muscle specimens in patients with esophageal motility disorders. Here, we describe the case of a patient with systemic sclerosis. Histological verification of the esophageal involvement in the pathological process was required for the treatment. There were no intra- and post- operational complications.

Endoscopic full-thickness muscle biopsy for rectal tissue sampling in patients with severe gut motility disorders: an initial experience (with video)

BACKGROUND AND AIMS

Diagnosis of GI neuromuscular diseases is mostly on the basis of symptomatology and is often unreliable. Pathologic analysis of affected tissue (eg, the myenteric plexus and muscle) is a potentially valuable method for both diagnosis and advancement of our knowledge about the biologic basis for these syndromes. However, until now access to the deeper layers of the GI tract has been limited, generally requiring invasive surgical techniques.

METHODS

We report a "close-then-resect" endoscopic full-thickness biopsy sampling (EFTB) technique using an over-the-scope clip and telescope for rectal muscle biopsy sampling in patients with suspected severe neuromuscular gut disorders. The main outcome measures were technical success and adverse events.

RESULTS

Thirteen patients (11 women; mean age 27 ± 5.4 years) with diffusely delayed colonic transit underwent EFTB. The mean (± standard deviation) procedure time was 30 ± 5.2 minutes. The mean size of the resected specimen was 18 ± 3.5 mm. Histologic full-thickness tissue samples were achieved for all patients. Postprocedural adverse events were reported in 2 patients, and both were graded as mild (1 self-limited bleeding and 1 with rectal pain). Hematoxylin and eosin staining of tissue samples confirmed adequate cross-sectional imaging of muscularis propria in all patients with excellent demonstration of the myenteric plexus and both layers of muscle. Two patients demonstrated a decrease in interstitial cells of Cajal as demonstrated by CD117 staining. No cases demonstrated appreciable inflammation involving myenteric ganglia.

CONCLUSIONS

Diagnostic EFTB with modified over-the-scope clip for the close-then-resect method appears to be a safe and effective technique to obtain adequate full-thickness rectal specimens, allowing for both quantitative and qualitative analysis for the diagnosis of neuromuscular GI dysmotility.

Endoscopic techniques for full thickness intestinal biopsy

PURPOSE OF REVIEW

Accurate diagnosis of gastrointestinal neuromuscular diseases requires full thickness biopsy for adequate histologic evaluation of the enteric neuromuscular and ancillary cells. Historically, this has been achieved by surgical approaches. An overview of procedure evolution and current techniques of endoscopic full thickness biopsy (EFTB) for diagnosis of gastrointestinal neuromuscular disorders will be presented.

RECENT FINDINGS

Emergence and advancement of endoscopic full thickness resection techniques has offered a less invasive, nevertheless an effective modality of tissue acquirement. Recently, clip-assisted close-then-cut EFTB has been utilized in clinical practice under research protocol. Early experience has shown that this technique provides an adequate full-thickness specimen including the myenteric plexus and ganglia cells, with acceptable safety profiles.

SUMMARY

EFTB is a promising means in diagnosing the nature of the disease and guiding therapy. Available animal and human studies have shown the noninferiority of endoscopic methods to surgical ones in term of adequacy of tissue samples, while potentially decreasing the risk and occurrence of complications. Further large prospective studies are needed to assess its efficacy, safety and impacts on patient's outcomes.

Endoscopic Full Thickness Resection

Recent advances in minimally invasive endoscopic approaches have pushed the boundaries of well-established resection techniques for therapeutic and diagnostic applications. Endoscopic full thickness resection techniques are a key development in the management of challenging epithelial and subepithelial lesions that are not amenable to conventional endoscopic resection methods and previously required a surgical approach. Endoscopic full thickness biopsy represents a paradigm shift in tissue acquisition and will enhance our understanding of the pathophysiology, and guide therapy, of gastrointestinal neuromuscular diseases, as well as other inflammatory and neoplastic conditions. This review highlights current tools and techniques available for endoscopic full thickness resection and biopsy, as well as outcomes from such interventions.

Endoscopic full-thickness resection using suture loop needle T-tag tissue anchors in the porcine stomach (with video)

BACKGROUND AND AIMS

Endoscopic full-thickness resection (EFTR) is still challenging, and a reliable technique is desirable. The aim of this study was to evaluate the feasibility of controlled EFTR using a pseudopolyp made from suture loop needle T-tag (SLNT) tissue anchors in ex vivo porcine stomachs.

METHODS

Five pig stomachs were used. Two concentric circumferential border mucosal incisions were made to facilitate isolating a target lesion for full-thickness excision and pseudopolyp formation. SLNT tissue anchors were placed with a fishing line around the edges of the larger outer incision by endoscopic suturing. A suture pulley was created in the center of the targeted area and brought outside for traction. A large inverted pseudopolyp of the targeted lesion was made, visualizing apposing serosa with traction on the suture pulley while simultaneously cinching the encircling fishing line. EFTR was then performed on the isolated targeted tissue with the use of a needle-knife.

RESULTS

Pseudopolyps were successful in all attempts. In the first attempt the encircling fishing line was cut, releasing the pseudopolyp during EFTR, with obvious leak. The remaining 4 EFTRs were performed with intact serosal apposing pseudopolyps and no air leaks. The median number of SLNT tissue anchors placed for a pseudopolyp was 5 (interquartile range, 4-5). The median size of full-thickness lesions was 37 mm (interquartile range, 29-49) and the median maximum pressure for the leak testing 9 mm Hg (interquartile range, 4-14) in the successful 4 attempts.

CONCLUSION

This proof of principle study suggests that EFTR with SLNT-fashioned pseudopolyps is feasible.

Diagnostic use of endoscopic full-thickness wall resection (eFTR)-a novel minimally invasive technique for colonic tissue sampling in patients with severe gastrointestinal motility disorders

BACKGROUND

Complex gastrointestinal (GI) motility disorders such as chronic intestinal pseudo-obstruction (CIPO) or Hirschsprung's disease (HD) are challenging to diagnose and treat appropriately. Thorough assessment of patient history, radiographic exams, endoscopy, and motility measurements aid in diagnostic workup, yet underlying histology is the cornerstone to enable a more distinct diagnosis of neuromuscular GI disorders. Traditionally, surgical procedures have been performed to obtain specimen suitable for accurate histologic analysis.

METHODS

We performed endoscopic full-thickness resection (eFTR) using a full-thickness-resection device (FTRD) under moderate propofol sedation in four patients with suspected severe neuromuscular gut disorders including CIPO.

KEY RESULTS

The mean age of the four patients was 43 y (range 19-56 y). Technical and histological success providing large colonic full-thickness tissue samples of excellent quality was achieved in all four patients (success rate 100%). The mean procedure time was 12 min (range 5-20 min). The mean diameter of the resected specimen was 21 mm (range 20-22 mm). No adverse events connected to the procedure itself occurred. Histology ranged from aganglionosis such as Hirschsprung's disease (HD) to hypoganglionosis and eosinophilic leiomyositis combined with lymphocytic ganglionitis in a third patient. Histology was unspecific in one patient.

CONCLUSION AND INFERENCES

EFTR allows safe and minimal invasive harvesting of ample full-thickness tissue samples for accurate histological analysis in patients with suspicion of neuromuscular gut disorders.

Endoscopic full-thickness resection of superficial colorectal neoplasms using a new over-the-scope clip system: A single-centre study

BACKGROUND AND AIM

Endoscopic full-thickness resection (EFTR) provides complete en-bloc resection with a histopathological evaluation of submucosal, muscular, and serosal layers. The aim of this study was to investigate the efficacy and safety of a novel over-the-scope device for colorectal EFTR.

MATERIAL AND METHODS

In this retrospective, observational, open-label case study, a total of 20 patients with superficial colorectal neoplasms, underwent EFTR using a new endoscopic full-thickness resection device (FTRD; Ovesco Endoscopy, Tübingen, Germany). Endoscopic treatment outcomes (technical success, rate of EFTR, adverse events) and early follow-up at three months, were analyzed.

RESULTS

We reported a 100% of technical success, defined as full-thickness resection. Among the R1 resections, histology was negative for neoplasm. Non-lifting adenomas had histology positive for adenocarcinoma: seven T1/G1/sm1; one T1/G1/sm2; one, who underwent a surgical resection, T1/G1/sm3. Mean size of the resected lesions was 26mm, ranging from 10 to 42mm. One (5%) patient developed abdominal pain, fever and leukocytosis and was treated conservatively with medical therapy. In all specimens, histological complete resection was confirmed.

CONCLUSIONS

EFTR is a feasible and effective technique that could become a valid alternative to EMR and ESD in the management of recurrent adenomas, no-lifting lesions and scars of R1 resections. However, prospective studies are needed to further evaluate the device and technique.

New devices and techniques for endoscopic closure of gastrointestinal perforations

Gastrointestinal perforations, which need to be managed quickly, are associated with high morbidity and mortality. Treatments used to close these perforations range from surgery to endoscopic therapy. Nowadays, with the development of new devices and techniques, endoscopic therapy is becoming more popular. However, there are different indications and clinical efficacies between different methods, because of the diverse properties of endoscopic devices and techniques. Successful management also depends on other factors, such as the precise location of the perforation, its size and the length of time between the occurrence and diagnosis. In this study, we performed a comprehensive review of various devices and introduced the different techniques that are considered effective to treat gastrointestinal perforations. In addition, we focused on the different methods used to achieve successful closure, based on the literature and our clinical experiences.

Innovative gastric endoscopic muscle biopsy to identify all cell types, including myenteric neurons and interstitial cells of Cajal in patients with idiopathic gastroparesis: a feasibility study (with video)

BACKGROUND AND AIMS

The pathophysiology of some GI neuromuscular diseases remains largely unknown. This is in part due to the inability to obtain ample deep gastric wall biopsies that include the intermuscular layer of the muscularis propria (MP) to evaluate the enteric nervous system, interstitial cells of Cajal (ICCs), and related cells. We report on a novel technique for gastric endoscopic muscle biopsy (gEMB).

METHODS

Patients with idiopathic gastroparesis were prospectively enrolled in a feasibility study by using a novel "no hole" gEMB. Main outcome measures were technical success, adverse events, and histologic confirmation of the intermuscular layer, including myenteric neurons and ICC. The gEMB was a double resection clip-assist technique. A site was identified on the anterior wall of the gastric body as recommended by the International Working Group on histologic techniques. EMR was performed to unroof and expose the underlying MP. The exposed MP was then retracted into the cap of an over-the-scope clip. The clip was deployed, and the pseudopolyp of MP created was resected. This resulted in a no-hole gEMB.

RESULTS

Three patients with idiopathic gastroparesis underwent gEMB. Patients had severe delayed gastric emptying with a mean (± standard deviation [SD]) of 49 ± 16.8% of retained gastric contents at 4 hours. They had no history of gastric or small-bowel surgery and did not use steroids or other immunosuppressive drugs. The gEMB procedure was successfully performed, with no procedural adverse events. Postprocedural abdominal pain was controlled with nonsteroidal anti-inflammatory agents and opioid analgesics. Mean length of resected MP was 10.3 ± 1.5 mm. Mean procedure time was 25.7 ± 6 minutes. Hematoxylin and eosin (H&E) staining of tissue samples confirmed the presence of both inner circular and outer longitudinal muscle, as well as the intermuscular layer. H&E staining showed reduced myenteric ganglia in 1 patient. In 2 patients, specialized immunohistochemistry was performed, which showed a marked decrease in myenteric neurons as delineated by an antibody to protein gene product 9.5 and a severe decrease in ICC levels across the muscle layers. At 1 month follow-up, upper endoscopy showed a well-healed scar in 2 patients and minimal ulceration with a retained clip in 1 patient. CT of the abdomen confirmed the integrity of the gastric wall in all patients. Because of lack of an immune infiltrate in the resected samples, patients were not considered suitable for immunosuppressive or steroid therapy.

CONCLUSIONS

gEMB is feasible and easy to perform, with acquisition of tissue close to surgical samples to identify myenteric ganglia, ICCs, and multiple cell types. The ability to perform gEMB represents a paradigm shift in endoscopic tissue diagnosis of gastric neuromuscular pathologies.

Endoscopic full-thickness resection: Current status

Conventional endoscopic resection techniques such as endoscopic mucosal resection or endoscopic submucosal dissection are powerful tools for treatment of gastrointestinal neoplasms. However, those techniques are restricted to superficial layers of the gastrointestinal wall. Endoscopic full-thickness resection (EFTR) is an evolving technique, which is just about to enter clinical routine. It is not only a powerful tool for diagnostic tissue acquisition but also has the potential to spare surgical therapy in selected patients. This review will give an overview about current EFTR techniques and devices.

Neural stem cell therapies for enteric nervous system disorders

The enteric nervous system is vulnerable to a range of congenital and acquired disorders that disrupt the function of its neurons or lead to their loss. The resulting enteric neuropathies are some of the most challenging clinical conditions to manage. Neural stem cells offer the prospect of a cure given their potential ability to replenish missing or dysfunctional neurons. This article discusses diseases that might be targets for stem cell therapies and the barriers that could limit treatment application. We explore various sources of stem cells and the proof of concept for their use. The critical steps that remain to be addressed before these therapies can be used in patients are also discussed. Key milestones include the harvesting of neural stem cells from the human gut and the latest in vivo transplantation studies in animals. The tremendous progress in the field has brought experimental studies exploring the potential of stem cell therapies for the management of enteric neuropathies to the cusp of clinical application.

Functions and imaging of mast cell and neural axis of the gut

Close association between nerves and mast cells in the gut wall provides the microanatomic basis for functional interactions between these elements, supporting the hypothesis that a mast cell-nerve axis influences gut functions in health and disease. Advanced morphology and imaging techniques are now available to assess structural and functional relationships of the mast cell-nerve axis in human gut tissues. Morphologic techniques including co-labeling of mast cells and nerves serve to evaluate changes in their densities and anatomic proximity. Calcium (Ca(++)) and potentiometric dye imaging provide novel insights into functions such as mast cell-nerve signaling in the human gut tissues. Such imaging promises to reveal new ionic or molecular targets to normalize nerve sensitization induced by mast cell hyperactivity or mast cell sensitization by neurogenic inflammatory pathways. These targets include proteinase-activated receptor (PAR) 1 or histamine receptors. In patients, optical imaging in the gut in vivo has the potential to identify neural structures and inflammation in vivo. The latter has some risks and potential of sampling error with a single biopsy. Techniques that image nerve fibers in the retina without the need for contrast agents (optical coherence tomography and full-field optical coherence microscopy) may be applied to study submucous neural plexus. Moreover, the combination of submucosal dissection, use of a fluorescent marker, and endoscopic confocal microscopy provides detailed imaging of myenteric neurons and smooth muscle cells in the muscularis propria. Studies of motility and functional gastrointestinal disorders would be feasible without the need for full-thickness biopsy.

A novel endoscopic prototype device for gastric full-thickness biopsy for the histopathologic diagnosis of GI neuromuscular pathology: in vivo porcine long-term survival study (with videos)

BACKGROUND

Many GI motility disorders are associated with underlying GI neuromuscular pathology, which requires full-thickness biopsies (FTB) for histopathologic diagnosis. Currently, none of the endoscopy-based attempts to obtain FTB specimens have proven suitable for routine use. This study evaluated a novel endoscopic prototype device (ED) for this purpose.

OBJECTIVE

To determine (1) the ability of the ED to obtain suitable FTB specimens, (2) associated complications, (3) feasibility of reliable defect closure, and (4) ability to evaluate intramural neuromuscular components.

DESIGN

Preclinical proof-of-concept study in 30 pigs.

SETTING

Animal laboratory.

INTERVENTION

Gastric FTB specimens were obtained with a circular cutter and anchor. The defect was closed by over-the-scope clips/T-tags. The resection site was inspected via laparoscopy. After 2 to 4 weeks, necropsy was carried out to evaluate late complications.

MAIN OUTCOME MEASUREMENTS

Feasibility, safety, and closure rate of the procedure. FTB specimens were assessed by histology/immunohistochemistry to visualize enteric neuromusculature.

RESULTS

A total of 29 of 30 procedures were successfully performed; one hemorrhage required endoscopic treatment. A total of 29 of 30 FTB specimens (mean diameter 9.1 mm) were retrieved in 7.1 ± 0.4 minutes (range 3.0-12.5 minutes), displaying optimal tissue quality. Defect closure took 10.8 ± 0.9 minutes (range 7.2-32 minutes). Laparoscopy did not reveal damage to adjacent organs. Necropsy showed well-healed scars at the resection site and no complications, peritonitis, or abscess formation. Histology showed smooth muscle layers and submucosal and myenteric ganglia.

LIMITATIONS

Survival animal pilot study, no patients.

CONCLUSION

The novel ED enabled safe harvesting of well-preserved FTB specimens. Defect closure proved to be reliable. All neuromuscular structures relevant for histopathologic evaluation of GI neuromuscular pathology were demonstrated. Further studies are needed to verify the efficacy of this prototype device in the entire gut and in humans.

Full-field optical coherence microscopy is a novel technique for imaging enteric ganglia in the gastrointestinal tract

BACKGROUND

Noninvasive methods are needed to improve the diagnosis of enteric neuropathies. Full-field optical coherence microscopy (FFOCM) is a novel optical microscopy modality that can acquire 1 μm resolution images of tissue. The objective of this research was to demonstrate FFOCM imaging for the characterization of the enteric nervous system (ENS).

METHODS

Normal mice and EdnrB(-/-) mice, a model of Hirschsprung's disease (HD), were imaged in three-dimensions ex vivo using FFOCM through the entire thickness and length of the gut. Quantitative analysis of myenteric ganglia was performed on FFOCM images obtained from whole-mount tissues and compared with immunohistochemistry imaged by confocal microscopy.

KEY RESULTS

Full-field optical coherence microscopy enabled visualization of the full thickness gut wall from serosa to mucosa. Images of the myenteric plexus were successfully acquired from the stomach, duodenum, colon, and rectum. Quantification of ganglionic neuronal counts on FFOCM images revealed strong interobserver agreement and identical values to those obtained by immunofluorescence microscopy. In EdnrB(-/-) mice, FFOCM analysis revealed a significant decrease in ganglia density along the colorectum and a significantly lower density of ganglia in all colorectal segments compared with normal mice.

CONCLUSIONS & INFERENCES

Full-field optical coherence microscopy enables optical microscopic imaging of the ENS within the bowel wall along the entire intestine. FFOCM is able to differentiate ganglionic from aganglionic colon in a mouse model of HD, and can provide quantitative assessment of ganglionic density. With further refinements that enable bowel wall imaging in vivo, this technology has the potential to revolutionize the characterization of the ENS and the diagnosis of enteric neuropathies.

Endoscopic full-thickness biopsy of the gastric wall with defect closure by using an endoscopic suturing device: survival porcine study

BACKGROUND

The pathogenesis of several common gastric motility diseases and functional GI disorders remains essentially unexplained. Gastric wall biopsies that include the muscularis propria to evaluate the enteric nervous system, interstitial cells of Cajal, and immune cells can provide important insights for our understanding of the etiology of these disorders.

OBJECTIVES

To determine the technical feasibility, reproducibility, and safety of performing a full-thickness gastric biopsy (FTGB) by using a submucosal endoscopy with mucosal flap (SEMF) technique; the technical feasibility, reproducibility, and safety of tissue closure by using an endoscopic suturing device; the ability to identify myenteric ganglia in resected specimens; and the long-term safety.

DESIGN

Single center, preclinical survival study.

SETTING

Animal research laboratory, developmental endoscopy unit.

SUBJECTS

Twelve domestic pigs.

INTERVENTIONS

Animals underwent an SEMF procedure with gastric muscularis propria resection. The resultant offset mucosal entry site was closed by using an endoscopic suturing device. Animals were kept alive for 2 weeks.

MAIN OUTCOME MEASUREMENTS

The technical feasibility, reproducibility, and safety of the procedure; the clinical course of the animals; the histological and immunochemical evaluation of the resected specimen to determine whether myenteric ganglia were present in the sample.

RESULTS

FTGB was performed by using the SEMF technique in all 12 animals. The offset mucosal entry site was successfully closed by using the suturing device in all animals. The mean resected tissue specimen size was 11 mm. Mean total procedure time was 61 minutes with 2 to 4 interrupted sutures placed per animal. Histology showed muscularis propria and serosa, confirming full-thickness resections in all animals. Myenteric ganglia were visualized in 11 of 12 animals. The clinical course was uneventful. Repeat endoscopy and necropsy at 2 weeks showed absence of ulceration at both the mucosal entry sites and overlying the more distal muscularis propria resection sites. There was complete healing of the serosa in all animals with minimal single-band adhesions in 5 of 12 animals. Retained sutures were present in 10 of 12 animals.

LIMITATIONS

Animal experiment.

CONCLUSIONS

FTGB by using the SEMF technique and an endoscopic suturing device is technically feasible, reproducible, and safe. Larger tissue specimens will allow improved analysis of multiple cell types.

In vivo histologic imaging of the muscularis propria and myenteric neurons with probe-based confocal laser endomicroscopy in porcine models (with videos)

BACKGROUND

The submucosal tunneling technique enables us to endoscopically access deeper tissue layers. Use of probe-based confocal laser endomicroscopy (pCLE) provides optical histologic imaging on the site.

OBJECTIVE

To determine the technical feasibility of ex vivo and in vivo pCLE imaging of the muscularis propria and myenteric neurons by using submucosal endoscopy with a mucosal flap safety valve (SEMF).

DESIGN

Acute porcine model study.

SETTING

Animal laboratory.

INTERVENTION

Two ex vivo and 6 in vivo porcine models were used. A submucosal space was created with SEMF, and a neuronal molecular probe was topically applied onto the muscularis. Confocal imaging of the stained muscularis was performed by using pCLE. The selected sites were sampled, and the histopathology of the sites was analyzed.

MAIN OUTCOME MEASUREMENTS

The two main outcome measures were the procedural success rate of submucosal access and the correlation between pCLE and histologic images.

RESULTS

Submucosal access to the pCLE study site was successful in all attempts (100%; 17/17 sites). The muscularis propria was visualized with pCLE in the ex vivo and in vivo porcine models in 83.3% of sites (20/24), and the neuron-like cells were identified in 41.7% of sites (10/24).

LIMITATIONS

Animal experiment.

CONCLUSION

The muscularis propria and myenteric neurons could be selectively visualized with pCLE in vivo.

Clinical value of duodenal biopsies--beyond the diagnosis of coeliac disease

At upper gastrointestinal endoscopy to investigate unexplained diarrhea and iron deficiency anemia, duodenal biopsies are often taken to exclude a diagnosis of coeliac disease. While histology remains the gold standard for this diagnosis, recent developments in serological testing may overtake this as a first line test and biopsy restricted to confirming the diagnosis. Established coeliac disease on biopsy is straightforward, but early lesions may pose a challenge. Newer endoscopic procedures such as push-pull enteroscopy (balloon enteroscopy) with biopsy allow access to the small bowel beyond the second part of the duodenum. Controversy remains as to what constitutes the normal histology of the duodenum, and small bowel. Lymphocytic duodenosis (increased intraepithelial lymphocytes with normal villous architecture) in patients with negative coeliac serology can be associated with Helicobacter pylori, drugs, autoimmune and other diseases including food allergy. Full thickness small intestinal biopsies can aid in investigation of enteric neuropathies in severe dysmotility disorders. Biopsies are also taken to investigate malabsorption due to suspected infectious and metabolic disorders. Despite highly active anti-retroviral therapy (HAART), immunosuppressed patients may be affected by duodenal pathogens. The histology of duodenal mucosa in acid related disorders reflects the damage seen at endoscopy. Although the prevalence of duodenal ulcer disease is decreasing, drugs causing ulceration remain an important disease entity. Recent observations in functional bowel disorders suggest that the duodenum may be a key site for pathology. In functional dyspepsia, patients with early satiety may have excess eosinophil infiltration, and the mast cell is probably a key player in the irritable syndrome in the small intestine.

Percutaneous endoscopically assisted transenteric full-thickness gastric biopsy: initial experience in humans

BACKGROUND

GI neuromuscular diseases (GINMD) can cause severe dysmotility and symptoms. Full-thickness biopsy specimens may help diagnose these disorders histologically.

OBJECTIVE

To assess a novel percutaneous endoscopically assisted transenteric (PEATE) biopsy method for obtaining full-thickness gastric tissue in patients with suspected GINMD.

DESIGN

Prospective proof-of-concept case series.

SETTING

Tertiary care gastroenterology unit.

PATIENTS

Ten patients (8 women, mean [standard deviation] age 43 [10] years) with gastroparesis-like symptoms (mean [standard deviation] gastroparesis cardinal symptom index 3.28 [1.46] out of 5) and/or clinical findings suggestive of a gastric GINMD.

INTERVENTIONS

All patients underwent PEATE biopsy during standard gastroscopy as an outpatient procedure. Tissue was stained for histology and immunohistochemistry of gut wall elements. Interstitial cells of Cajal (ICC) counts were compared with archived normal gastric tissue from control gastrectomies.

MAIN OUTCOME MEASUREMENTS

Biopsy success, complications, histopathological findings according to the London Classification of GINMD.

RESULTS

Full-thickness antral tissue suitable for analysis was obtained in 9 in 10 patients (90%). PEATE biopsy was well tolerated by all patients without complications. Histology suggested GINMD in 4 of 9 cases (44%), with possible degenerative leiomyopathy in 2, probable inflammatory leiomyopathy in 1, and abnormal ICC networks (>50% reduction in ICC counts) in 1 patient.

LIMITATIONS

PEATE biopsy specimen size is smaller than a standard laparoscopic full-thickness biopsy.

CONCLUSIONS

PEATE full-thickness gastric biopsy is a simple and safe method of assessing histopathological abnormalities in gastric GINMD without the need for laparoscopy or general anesthesia.

Colonic endoscopic full-thickness biopsies: from the neuropathological analysis of the myenteric plexus to the functional study of neuromuscular transmission

BACKGROUND

Better understanding of the pathophysiological mechanisms involved in severe dysmotility disorders is crucial to improve patient management and identify novel therapeutic targets. Recent studies suggested that endoscopic full-thickness biopsies (eFTBs) could be developed as an alternative to surgical biopsies. However, currently it remains unknown whether eFTBs would allow myenteric plexus analysis on whole mounts and the evaluation of neuromuscular transmission.

OBJECTIVE

To determine with eFTB specimens the ability to analyze on whole mounts the key parameters of the myenteric plexus, ie, ganglia and neurons, and to perform functional evaluation of neuromuscular transmission.

DESIGN

An experimental pilot study in 6 pigs was conducted in accordance with French institutional guidelines.

INTERVENTION

Under general anesthesia, pigs underwent a rectosigmoidoscopy. In each pig, an eFTB was performed at 25, 30, and 35 cm from the anal margin with an EMR-based technique. Tissue specimens were immediately processed for immunohistochemical and/or functional ex vivo analysis of neuromuscular transmission. In 2 pigs, over-the-scope clips were used to seal the perforation.

MAIN OUTCOME MEASUREMENTS

Feasibility of obtaining specimens containing myenteric plexus and muscularis propria, quantitative and standardized immunohistochemical evaluation of ganglia and myenteric neurons, ex vivo assessment of neuromuscular transmission and its pharmacology, and closure rate (ancillary study).

RESULTS

Adequate tissue specimens were obtained in 100% of the procedures, on average, in 6±2 minutes. Immunohistochemical analysis of a whole mount of the myenteric plexus showed that each eFTB contained 14±5 ganglia and 1562±1066 myenteric neurons. In circular muscle strips, electrical field stimulation or exposure to a pharmacological agent induced a specific tissue response. A successful closure was achieved in 50% of cases.

LIMITATIONS

Nonsurvival study; safety of the procedure needs to be specifically assessed and compared with recently published data.

CONCLUSIONS

We demonstrate, for the first time, that full-thickness biopsy specimens obtained by using an endoscopic approach allow the performance of a precise study of the ENS phenotype on whole mounts of the myenteric plexus and the performance of functional studies such as evaluation of neuromuscular transmission. However, further studies are warranted to identify the optimal and safest endoscopic procedure before application of eFTB in humans.

Gastrointestinal neuromuscular pathology in chronic constipation

Some patients with chronic constipation may undergo colectomy yielding tissue appropriate to diagnosis of underlying neuromuscular pathology. The analysis of such tissue has, over the past 40 years, fueled research that has explored the presence of neuropathy, myopathy and more recently changes in interstitial cells of Cajal (ICC). In this chapter, the data from these studies have been critically reviewed in the context of the significant methodological and interpretative issues that beset the field of gastrointestinal neuromuscular pathology. On this basis, reductions in ICC appear to a consistent finding but one whose role as a primary cause of slow-transit constipation requires further evaluation. Findings indicative of significant neuropathy or myopathy are variable and in many studies subject to considerable methodological bias. Methods with practical diagnostic utility in the individual patient have rarely been employed and require further validation in respect of normative data.

Diabetic gastroparesis: what we have learned and had to unlearn in the past 5 years

Diabetic gastroparesis is a disorder that occurs in both type 1 and type 2 diabetes. It is associated with considerable morbidity among these patients and with the resultant economic burden on the health system. It is primarily a disease seen in middle-aged women, although the increased predisposition in women still remains unexplained. Patients often present with nausea, vomiting, bloating, early satiety and abdominal pain. The pathogenesis of this complex disorder is still not well understood but involves abnormalities in multiple interacting cell types including the extrinsic nervous system, enteric nervous system, interstitial cells of Cajal (ICCs), smooth muscles and immune cells. The primary diagnostic test remains gastric scintigraphy, although other modalities such as breath test, capsule, ultrasound, MRI and single photon emission CT imaging show promise as alternative diagnostic modalities. The mainstay of treatment for diabetic gastroparesis has been antiemetics, prokinetics, nutritional support and pain control. In recent years, gastric stimulation has been used in refractory cases with nausea and vomiting. As we better understand the pathophysiology, newer treatment modalities are emerging with the aim of correcting the underlying defect. In this review, what has been learned about diabetic gastroparesis in the past 5 years is highlighted. The epidemiology, pathogenesis, diagnosis and treatment of diabetic gastroparesis are reviewed, focusing on the areas that are still controversial and those that require more studies. There is also a focus on advances in our understanding of the cellular changes that underlie development of diabetic gastroparesis, highlighting new opportunities for targeted treatment.

A novel method of full-thickness gastric biopsy via a percutaneous, endoscopically assisted, transenteric approach

BACKGROUND

Pathologic changes of the enteric nervous system of the stomach have been described in gastroparesis. Because the enteric nervous system lies within the myenteric plexus between the muscle layers of the stomach, it is not accessible by standard biopsy forceps. Thus, tissue must be obtained by laparoscopy or laparotomy. Obtaining full-thickness biopsies with a less-invasive method would be an ideal alternative.

OBJECTIVE

To assess the safety and feasibility of a novel method of gastric, full-thickness biopsy by using a percutaneous, endoscopically assisted, transenteric approach.

DESIGN

Experimental pilot study in 3 dogs, approved by the animal care committee.

INTERVENTION

Under general anesthesia, dogs underwent gastroscopy, and a suitable biopsy area was chosen, based on indentation of the anterior stomach wall by external finger pressure on the abdominal skin and by endoscope transillumination. Using sterile technique, we made a 3-mm incision through the abdominal skin, and a spring-loaded, 14-gauge biopsy needle was used to take 4 separate antral biopsies from each dog, with no mucosal or abdominal closure intervention.

MAIN OUTCOME MEASUREMENTS

Feasibility of obtaining enteric nervous system tissue; morbidity and mortality at 4 weeks; gross pathology at necropsy.

RESULTS

The procedure was well tolerated by the dogs, with no morbidity or mortality at any time, up to 4 weeks after the procedure. Adequate tissue specimens were obtained for histologic analysis of all layers of the stomach, including enteric nervous system elements.

LIMITATIONS

Biopsy size was smaller than a surgical biopsy size.

CONCLUSION

The percutaneous, endoscopically assisted, transenteric approach, full-thickness biopsy technique is safe and obtains enteric nervous tissue in a simple, minimally invasive manner.

Gastroparesis and functional dyspepsia: excerpts from the AGA/ANMS meeting

BACKGROUND

Despite the relatively high prevalence of gastroparesis and functional dyspepsia, the aetiology and pathophysiology of these disorders remain incompletely understood. Similarly, the diagnostic and treatment options for these two disorders are relatively limited despite recent advances in our understanding of both disorders.

PURPOSE

This manuscript reviews the advances in the understanding of the epidemiology, pathophysiology, diagnosis, and treatment of gastroparesis and functional dyspepsia as discussed at a recent conference sponsored by the American Gastroenterological Association (AGA) and the American Neurogastroenterology and Motility Society (ANMS). Particular focus is placed on discussing unmet needs and areas for future research.

Preliminary performance of a flexible cap and catheter-based endoscopic suturing system

BACKGROUND

Translation of natural orifice transluminal endoscopic surgery (NOTES) into clinical applications requires efficient and reliable enterotomy closure.

OBJECTIVE

To evaluate a prototype endoscopic suturing system for enterotomy closure.

DESIGN

This study took place in an ex vivo animal laboratory. Isolated porcine stomachs were contained within a plastic molded abdominal torso. The device specifications included a curved needle, end-cap assembly with a side-mounting wire-actuation channel, a needle-exchange assembly that operates within an endoscopic working channel, and a detachable needle tip attached to suture material.

INTERVENTIONS

Mucosal templates (3-cm circular markings) for targeted suture placement were created along the anterior wall of the stomach (cardia, antrum, and body). Device performance and functionality were studied in 3 ways: suture placement, purse-string closure, and edge-to-edge gastrotomy closure. Interrupted and running stitches were placed with the endoscope straight and retroflexed. Simple leak testing was conducted.

RESULTS

Sutures could accurately be placed at preset templated markings. Creation of a purse-string gastrotomy closure confirmed the capability to place a set of circumferential full-thickness running sutures during a single endoscopic intubation that resulted in a leak-proof closure. Edge-to-edge full-thickness tissue apposition was accomplished, which provided a water-tight closure of an 18-mm gastrotomy. The device worked consistently, without any problems.

CONCLUSIONS

This endoscopic suturing device provided accurate placement of full-thickness sutures during a single intubation and permitted satisfactory tissue apposition. Standardized leak testing is needed for further development and evaluation of new devices. The catheter-driven needle actuator and the transfer-component system were intuitive and universally adaptable to any endoscope. This closure device may advance transluminal therapies by offering a secure, efficient method of hollow viscus closure.

Pilot study for in vivo cellular imaging of the muscularis propria and ex vivo molecular imaging of myenteric neurons (with video)

BACKGROUND

It is challenging to optimally sample the muscularis propria endoscopically for the diagnosis of muscle layer diseases, especially for motility disorders resulting from neuroenteric dysfunction.

OBJECTIVES

Ultramagnification in vivo imaging of the muscularis mucosa and ex vivo identification of myenteric neuronal elements by confocal microscopy.

DESIGN

Ex vivo and in vivo porcine animal studies.

SETTING

Short-term study in an animal laboratory.

INTERVENTIONS

The muscularis propria in the stomach and esophagus was accessed by resecting the mucosal layer with endoscopic submucosal dissection or cap EMR techniques or by creating a submucosal space by the submucosal endoscopy with mucosal flap technique. The muscularis propria was stained with Nissl stains and 2 types of neuronal molecular stains. The muscular layer was imaged with the endocytoscope in vivo. The muscularis stained with molecular-based stains was also evaluated with a confocal microscope.

RESULTS

Cellular microstructures resembling spindle-shaped smooth muscle cells were visualized by endocytoscopy in vivo. Confocal endoscopic microscopy demonstrated that in vivo topical application of neuronal molecular stains successfully stained the muscularis and specifically highlighted neuron-like cells.

LIMITATION

Animal model pilot study.

CONCLUSIONS

In vivo endoscopic histologic evaluation of the muscularis propria is technically feasible and easy. Minimally invasive advanced endoscopic imaging may be useful for the diagnosis and study of neuroenteric disorders at the level of the muscularis propria, avoiding surgical full-thickness tissue sampling.

Neural stem cell transplantation in the enteric nervous system: roadmaps and roadblocks

The enteric nervous system (ENS) is vulnerable to a variety of genetic, metabolic or environmental threats, resulting in clinical disorders characterized by loss or malfunction of neuronal elements. These disorders have been difficult to treat and there is much enthusiasm for novel therapies such as neural stem cell (NSC) transplantation to restore ENS function in diseased segments of the gut. Recent research has indicated the potential for a variety of innovative approaches to this effect using NSC obtained from the central nervous system (CNS) as well as gut derived enteric neuronal progenitors. The main goal of this review is to summarize the current status of NSC research as it applies to the ENS, delineate a roadmap for effective therapeutic strategies using NSC transplantation and point out the numerous challenges that lie ahead.

New techniques in the tissue diagnosis of gastrointestinal neuromuscular diseases

Gastrointestinal neuromuscular diseases are 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. Common to most of these diseases are symptoms of impaired motor activity which manifest as slowed or obstructed transit with or without evidence of transient or persistent radiological visceral dilatation. A variety of histopathological techniques and allied investigations are being increasingly applied to tissue biopsies from such patients. This review outlines some of the more recent advances in this field, particularly in the most contentious area of small bowel disease manifesting as intestinal pseudo-obstruction.