Published papers

BACKGROUND AND STUDY AIMS: Small intestinal pathology in hemodialysis (HD) patients has been studied in only a small number of retrospective case series. One method for noninvasively surveying small intestinal disorders is video capsule endoscopy (VCE). The primary aim of this study was to investigate the prevalence of small intestinal abnormalities among asymptomatic maintenance HD outpatients using VCE. The secondary aim was to assess the clinical impact of these abnormalities. PATIENTS AND METHODS: This study consisted of two phases. In phase I, a cross-sectional study, a cohort of patients who received maintenance HD three times weekly at an outpatient hemodialysis clinic were studied using VCE. Phase II was a prospective cohort study with follow up for 1 year after VCE. RESULTS: Fifty-six patients were enrolled in this study, and two were excluded from analysis due to capsule retention in the stomach. The prevalence of small bowel abnormalities in HD patients was 64.8 % (35/54) (95 % confidential interval 52.1 % - 77.6 %). Of 54 patients, 21 (38.9 %) had mucosal lesions, 10 (18.5 %) had vascular lesions, and 4 (7.4 %) had both lesion types. During the 1-year follow-up period, events occurred in four patients. A small bowel-associated event was observed in one patient, who underwent laparoscopy-assisted small intestinal partial resection 3 months after diagnosis by VCE. All patients in whom events were seen had small bowel abnormalities; no events were observed in the VCE-negative group. CONCLUSIONS: Although asymptomatic maintenance HD patients had a high prevalence of small bowel abnormalities (64.8 %), they did not have a high incidence of small bowel-associated events during the 1-year follow-up.

AIM: To elucidate the safety of percutaneous endoscopic gastrostomy (PEG) under steady pressure automatically controlled endoscopy (SPACE) using carbon dioxide (CO2). METHODS: Nine patients underwent PEG with a modified introducer method under conscious sedation. A T-tube was attached to the channel of an endoscope connected to an automatic surgical insufflator. The stomach was inflated under the SPACE system. The intragastric pressure was kept between 4-8 mmHg with a flow of CO2 at 35 L/min. Median procedure time, intragastric pressure, median systolic blood pressure, partial pressure of CO2, abdominal girth before and immediately after PEG, and free gas and small intestinal gas on abdominal X-ray before and after PEG were recorded. RESULTS: PEG was completed under stable pneumostomach in all patients, with a median procedural time of 22 min. Median intragastric pressure was 6.9 mmHg and median arterial CO2 pressure before and after PEG was 42.1 and 45.5 Torr (NS). The median abdominal girth before and after PEG was 68.1 and 69.6 cm (NS). A mild free gas image after PEG was observed in two patients, and faint abdominal gas in the downstream bowel was documented in two patients. CONCLUSION: SPACE might enable standardized pneumostomach and modified introducer procedure of PEG.

Endoscopy plays a significant role in the diagnosis, management, and surveillance of colorectal cancer (CRC) and inflammatory bowel diseases (IBDs). Moreover, magnifying endoscopy and image-enhanced endoscopy has a crucial role in the clinical setting. Recently, a super-magnifying endoscope has been developed, and two devices, confocal laser endomicroscopy (CLE) and an endocytoscopy system (ECS), which allow in vivo microscopic inspection of the microstructural mucosal features of the gastrointestinal tract, are currently available. Studies on the use of ECS in CRC were reported by a Japanese group. Additionally, a few studies on the use of ECS in IBD have been reported. CLE has been shown to be reliable in assessing the activity of the disease in IBDs in both ulcerative colitis and Crohn's disease. Various published studies evaluated the use of CLE during colonoscopy to distinguish colorectal polyp pathology and neoplasia. However, these studies are heterogeneous, and further evidence is necessary to confirm the efficacy of CLE.

Previously, we proposed a rare autosomal recessive inherited enteropathy characterized by persistent blood and protein loss from the small intestine as chronic nonspecific multiple ulcers of the small intestine (CNSU). By whole-exome sequencing in five Japanese patients with CNSU and one unaffected individual, we found four candidate mutations in the SLCO2A1 gene, encoding a prostaglandin transporter. The pathogenicity of the mutations was supported by segregation analysis and genotyping data in controls. By Sanger sequencing of the coding regions, 11 of 12 other CNSU patients and 2 of 603 patients with a diagnosis of Crohn's disease were found to have homozygous or compound heterozygous SLCO2A1 mutations. In total, we identified recessive SLCO2A1 mutations located at seven sites. Using RT-PCR, we demonstrated that the identified splice-site mutations altered the RNA splicing, and introduced a premature stop codon. Tracer prostaglandin E2 uptake analysis showed that the mutant SLCO2A1 protein for each mutation exhibited impaired prostaglandin transport. Immunohistochemistry and immunofluorescence analyses revealed that SLCO2A1 protein was expressed on the cellular membrane of vascular endothelial cells in the small intestinal mucosa in control subjects, but was not detected in affected individuals. These findings indicate that loss-of-function mutations in the SLCO2A1 gene encoding a prostaglandin transporter cause the hereditary enteropathy CNSU. We suggest a more appropriate nomenclature of "chronic enteropathy associated with SLCO2A1 gene" (CEAS).

Although ileocolonoscopy is the gold standard for diagnosis of inflammatory bowel disease and is useful for assessing the disease severity in the colon and terminal ileum, several alternative diagnostic techniques have been developed recently. For ulcerative colitis (UC), magnification colonoscopy, endocytoscopy, and confocal laser endomicroscopy enable assessment of histological inflammation without the need for biopsy. Capsule endoscopy is useful for detection of small intestinal and colonic lesions in both female and male patients. For UC, capsule endoscopy may be useful for evaluating colonic inflammation in patients with a previous poor colonoscopy experience, while it should be used only in Crohn's disease (CD) patients with unexplained symptoms when other examinations are negative. Magnetic resonance enterography (MRE) is particularly useful for detecting transmural inflammation, stenosis, and extraintestinal lesions, including abscesses and fistulas. MRE is also useful when evaluating small and large intestinal lesions, even in cases with severe strictures in which full evaluation of the small bowel would be virtually impossible using other devices. Therefore, the appropriate diagnostic devices for detecting CD lesions in the small and large intestine should be used.

OBJECTIVES: Upper gastrointestinal endoscopy is mostly performed under sedation and has a low yield of relevant gastric lesions in patients without alarm symptoms. Simpler screening tests such as capsule endoscopy could be helpful, but gastric visualization is insufficient with the current passive capsules. A magnetically guided gastric capsule was prospectively evaluated in patients with routine indications for gastroscopy. METHODS: A total of 189 symptomatic patients (105 male; mean age 53 y) from 2 French centers subsequently and blindly underwent capsule and conventional gastroscopy by 9 and 6 examiners, respectively. The final gold standard was unblinded conventional gastroscopy with biopsy under propofol sedation. Main outcome was accuracy (sensitivity/specificity) of capsule gastroscopy for diagnosis of major gastric lesions, defined as those lesions requiring conventional gastroscopy for biopsy or removal. RESULTS: Twenty-three major lesions were found in 21 patients. Capsule accuracy was 90.5% [95% confidence interval (CI), 85.4%-94.3%] with a specificity of 94.1% (95% CI, 89.3%-97.1%) and a sensitivity of 61.9% (95% CI, 38%-82%). Accuracy did not correlate with lesion location, gastric luminal visibility, examiner case volume, or examination time. Of the remaining 168 patients, 94% had minor and mostly multiple lesions; the capsule made a correct diagnosis in 88.1% (95% CI, 82.2%-92.6%), with gastric visibility and lesion location in the proximal stomach having significant influence. All patients preferred capsule gastroscopy. CONCLUSIONS: In a prospective and strictly blinded study, magnetically guided capsule gastroscopy was shown to be feasible in clinical practice and was clearly preferred by patients. Improvements in capsule technology may render this technique a future alternative to gastroscopy.

A broad range of modalities for colorectal cancer (CRC) screening are available worldwide. Although recent studies have been demonstrating developments of CRC screening modalities including colonoscopy, computed tomography colonography or colon video capsule colonoscopy remains the gold standard for the early detection of adenoma or CRC. Because patient preferences and availability of resources play an important role in the selection of CRC screening options, further improvement of each screening modality and its associated research is necessary to consider its involvement in clinical practice.

More than a decade has passed since small-bowel capsule endoscopy (CE) was first reported. Small-bowel CE is a non-invasive tool that allows visualization of the entire small-intestinal mucosa and facilitates detection of small-intestinal abnormalities. Several studies have shown benefit of small-bowel CE for certain disorders. Because it is non-invasive, CE has been applied to other organs including the esophagus, stomach, and colon. The main indications for esophageal CE (ECE) are screening for gastroesophageal reflux disease/Barrett's esophagus, and esophageal varices. However, the clinical benefit of ECE is unconfirmed. Magnetically guided CE (MGCE) was developed to visualize the gastric mucosa. MGCE is a new concept with room for improvement of capsule navigation and the preparation protocol. Recently, two new small-bowel CE tools were released. First-generation colon CE (CCE-1) has moderate sensitivity and specificity compared with colonoscopy for colorectal neoplasia surveillance. To obtain higher accuracy, a second-generation CCE (CCE-2) was developed with a high sensitivity for detecting clinically relevant polypoid lesions. A possible application of CCE is for inflammatory bowel disease. In the near future, CE may include diagnostic and therapeutic functions such as magnifying endoscopy systems, targeted biopsy forceps, and drug delivery systems.

OBJECTIVE: Although it is known that the chemokines CXCL12 and CCL20 are expressed in the intestine, their contribution to lymphocyte homing has not been investigated in detail. The authors investigated whether the CXCL12-CXCR4 and CCL20-CCR6 systems are involved in T lymphocyte-endothelial interaction in microvessels of the small and large intestines. METHODS: Labeled lamina proprial lymphocytes (LPLs) were administered to mice, and their adhesion to microvessels of normal and TNF-alpha -induced inflamed intestinal mucosa was observed under an intravital microscope. Antibodies against CXCL12, CCL-20, or CCL-25 were administered prior to lymphocyte administration, and in some experiments CXCR4 or CCR6 on LPLs was desensitized with an excess amount of chemokine. RESULTS: LPLs adhered to microvessels of the ileum and colon, and TNF-alpha induced a significant accumulation at both sites. Blocking of the CXCL12-CXCR4 system significantly inhibited the LPL adhesion in the ileum and colon under both normal and TNF-alpha -treated conditions. However, blocking of the CCL20-CCR6 system significantly attenuated LPL adhesion only under a TNF-alpha -treated condition. There was an additive inhibitory effect on LPL adherence by CXCL12 and CCL20 blocking in TNF-alpha -induced inflamed intestines. There was also an additive function of the CCL25-CCR9 system in LPL accumulation in the small intestine. CONCLUSION: Several chemokine systems may play significant roles cooperatively in vivo in LPL adherence to microvessels of intestinal mucosa.

BACKGROUND AND STUDY AIMS: Endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) has improved the success rate of en-bloc resection. We report here on a new technique using an external grasping forceps. PATIENTS AND METHODS: A total of 25 patients with suitable EGCs over 10 mm in diameter located in the gastric body were enrolled. After submucosal injection followed by circumcision of the lesion with a needle-knife, an external grasping forceps was introduced with the help of a second grasping forceps and anchored at the distal margin of the lesion. With gentle oral traction applied with this forceps, the lesion was dissected endoscopically in retroversion from the aboral side. RESULTS: The mean lesion size was 15.0 mm (range 10 - 25 mm). Using the technique described, all lesions could be resected en bloc with free margins. The mean procedure time was 45 min (range 30 - 80 minutes). No significant bleeding requiring blood transfusion or perforation occurred. CONCLUSIONS: This technical modification may simplify and shorten the gastric ESD procedure, except for lesions in distal locations, without compromising the efficacy.

We devised and evaluated a clinical pathway (CP) protocol for patients with bleeding peptic ulcers (BPU). Patients without severe comorbidities, who had been diagnosed with BPU and who had undergone endoscopic treatment, were enrolled in our study. The CP adaptation rate for BPU patients was 78.8% (89/113). The variance rate was 13.5% (12/89). The median length of admission was 10.0 +/- 4.6 days (n = 78) before and 7.4 +/- 2.9 days (n = 77) after introducing CP. Our CP for BPU was safe and resulted in shorter hospital stays and, therefore, cost reductions. In elder patients, our CP was also successful, but the variance rate was higher than in younger patients.

AIM: To evaluate the effectiveness of trimodal imaging endoscopy (TME) to detect another lesion after endoscopic submucosal dissection (ESD) for superficial gastric neoplasia (SGN). METHODS: Surveillance esophagogastroduodenoscopy (EGD) using a TME was conducted in 182 patients that had undergone ESD for SGN. Autofluorescence imaging (AFI) was conducted after white-light imaging (WLI). When SGN was suspicious, magnifying endoscopy with narrow-band imaging (ME-NBI) was conducted. Final diagnoses were made by histopathologic findings of biopsy specimens. The detection rates of lesions in WLI, AFI, and NBI, and the characteristics of lesions detected by WLI and ones missed by WLI but detected by AFI were examined. The sensitivity, specificity, and accuracy of endoscopic diagnosis using WLI, AFI and ME-NBI were evaluated. RESULTS: In 242 surveillance EGDs, 27 lesions were determined pathologically to be neoplasias. Sixteen early gastric cancers and 6 gastric adenomas could be detected by WLI. Sixteen lesions were reddish and 6 were whitish. Five gastric neoplasias were missed by WLI but were detected by AFI, and all were whitish and protruded gastric adenomas. There was a significant difference in color and pathology between the two groups (P = 0.006). Sensitivity, specificity and accuracy in ME-NBI were higher than those in both WLI and AFI. Specificity and accuracy in AFI were lower than those in WLI. CONCLUSION: Surveillance using trimodal imaging endoscopy might be useful for detecting another lesion after endoscopic submucosal dissection for superficial gastric neoplasia.

Pyogenic granulomas usually occur on the skin or oral mucosa; however, they rarely develop in the gastrointestinal tract, particularly in the ileum. We report the case of an 82-year-old female who experienced occasional bloody stools. Initially, no significant bleeding source could be identified via conventional endoscopy; however, repeat capsule endoscopy identified a bleeding polyp (8 mm) in the ileum. Therefore, we resected the polyp via double-balloon enteroscopy. Histopathological findings showed increased, lobulated, and enlarged capillaries and desquamated epithelium indicative of epithelial erosion. In addition, neutrophil-predominant inflammatory cell infiltrate and interstitial edema were observed in the intercapillary stroma. Immunohistochemical analysis showed positive staining for vascular endothelial cell markers. Previous reports have mentioned that pyogenic granulomas in the oral cavity were associated with the female hormonal receptor, vascular endothelial growth factor, and proliferative immune markers; however, no significant staining was observed in our patient. This is the first report discussing an association between pyogenic granulomas and these markers. Pyogenic granulomas in the ileum are rare and may cause fatal anemia. Pyogenic granulomas should be considered in the differential diagnosis of obscure gastrointestinal bleeding.

BACKGROUND AND AIM: We have reported that second-generation colon capsule endoscopy (CCE-2) might be feasible for assessing the severity of mucosal inflammation in ulcerative colitis (UC). However, because of the low rate (69%) of complete evaluation of the colon and owing to inadequate cleansing. We believe that the method of bowel preparation could be improved by reducing volume. In the present study, we attempted to improve the colon-cleansing regimen in order to optimize the usefulness of CCE-2 in the management of UC patients. METHODS: Twenty patients with histologically confirmed UC were enrolled. Patients took a maximum 2.2 L lavage solution (polyethylene glycol solution and magnesium citrate) in two or three divided doses. To assess the effectiveness of the modified bowel preparation regimen, we evaluated the rate of total colonobservation, the effectiveness of bowel cleansing, andinterobserver agreement in assessing UC disease activity. We used a four-point grading scale (poor, fair, good, and excellent) for evaluating the quality of bowel cleansing. Matts' endoscopic score was used to evaluate disease activity. RESULTS: The rate of total colon observation was 85%, and 15 patients (75%) excreted the CCE-2 within 8 h. The proportion of excellent plus good cleansing was approximately 60%. There was a substantial interobserver agreement (kappa = 0.777) in assessment of overall cleansing, which was still substantial at the fair cleansing level (kappa = 0.700). CONCLUSION: Using CCE-2, the modified bowel preparation regimen, with reduced volume has the potential to succeed in the evaluation of mucosal severity in UC.

BACKGROUND AND AIM: Although intestinal obstruction as a result of sigmoid volvulus (SV) may be successfully resolved using endoscopic detorsion, surgical treatment remains the main therapeutic strategy. We evaluated the endoscopic detorsion procedure using unsedated water-immersion colonoscopy for the treatment of SV. METHODS: A retrospective chart review was conducted on the clinical background and prognosis of 21 SV patients who underwent 71 endoscopic detorsion procedures using unsedated, water-immersion colonoscopy. RESULTS: In all, 14 (67%) male and seven (33%) female patients, with a mean age of 73 years (range, 54-95 years) were enrolled; 86% were >70 years of age. Among these patients, 90% had a background of key predisposing factors. In the 21 patients, endoscopic detorsion was successfully done using unsedated water-immersion colonoscopy. SV recurred in 10 patients at a median of 180 days. Endoscopic detorsion for recurrent SV was successfully achieved in all cases, and none of the secondary cases became severe. Only male patients were observed to experience three or more recurrent episodes of SV. CONCLUSIONS: SV occurred most commonly in elderly patients with a surgical risk. Our experience suggests that conservative endoscopic treatment using unsedated water-immersion colonoscopy is a safe, reasonable, conservative endoscopic approach for elderly patients in the absence of necrotic findings. We currently use this procedure in most of our cases.

Endoscopic submucosal dissection (ESD) has been established as a standard treatment for early stage gastric cancer (EGC) in Japan and has spread worldwide. ESD has been used not only for EGC but also for early esophageal and colonic cancers. However, ESD is associated with several adverse events, such as bleeding and perforation, which requires more skill. Adequate tissue tension and clear visibility of the tissue to be dissected are important for effective and safe dissection. Many ESD methods using traction have been developed, such as clip-with-line method, percutaneous traction method, sinker-assisted method, magnetic anchor method, external forceps method, internal-traction method, double-channel-scope method, outerroute method, double-scope method, endoscopic-surgical-platform, and robot-assisted method. Each method has both advantages and disadvantages. Robotic endoscopy, enabling ESD with a traction method, will become more common due to advances in technology. In the near future, simple, noninvasive, and effective ESD using traction is expected to be developed and become established as a worldwide standard treatment for superficial gastrointestinal neoplasias.

There are various diagnostic approaches for parasitic infections, including microscopic identification of parasites in the stool or biopsy samples from the intestinal mucosa, antigen testing of feces or serum, polymerase chain reaction (PCR) testing, and serology. Endoscopy is sometimes used for direct confirmation of parasite infection and as a therapeutic option for removal. In recent years, innovations in endoscopy have advanced remarkably with regards to endoscopic devices as well as diagnostic and therapeutic endoscopical methods. Several new endoscopic devices are now used for diagnostic and therapeutic approaches to parasitic infections. In the present article, we have focused on in vivo imaging of parasitic infections. In vivo images of parasites were obtained using various endoscopic methods such as high-definition endoscopy, super-magnifying endoscopy, and video capsule endoscopy.

Conventional ileocolonoscopy and barium small bowel follow-through are useful techniques for assessing the extension and severity of disease in patients with inflammatory bowel disease (IBD). More recently, novel techniques to enable IBD diagnosis have been developed, such as capsule endoscopy (CE), balloon enteroscopy (BE), computed tomography enterography (CTE) and magnetic resonance enterography (MRE). The advantages of CE and BE are that they enable mucosal assessment directly whereas the usefulness of CTE/MRE is in its ability to enable detection of transmural inflammation, stenosis, and extraintestinal lesions including abscesses and fistulas. In ulcerative colitis (UC), colitis-associated dysplasia/cancer is one of the critical complications in patients with chronic disease. Detection of colitis-associated cancer is difficult in cases with inflammation. Magnification colonoscopy has been used to detect dysplasia in patients with chronic UC. Furthermore, colon CE and endocytoscopy have also developed and these might be used for selected patients in the near future.

BACKGROUND AND AIM: Colon capsule endoscopy has already been used for colon visualization and detection of polyps but its applicability to inflammatory bowel disease is still unconfirmed. The aim of this study was to assess the feasibility of evaluating the severity of mucosal inflammation in patients with ulcerative colitis (UC) using a second-generation colon capsule endoscope (CCE-2). METHODS: Forty patients with histological confirmed diagnosis of UC were enrolled. Low-volume (2 L) polyethylene glycol solution with prokinetics (mosapride citrate and metoclopramide) regimen was used for the bowel preparation. In Phase 1, consisting of 10 patients, to confirm appropriate CCE-2 bowel preparation for UC. In Phase 2, consisting of 30 patients, CCE-2 was performed with a fixed bowel preparation regimen. CCE-2 findings were recorded for 8 h starting from capsule ingestion and conventional colonoscopy was subsequently performed on the same day. CCE-2 procedure completion rate and the colon cleansing level with a 4-point grading scale (poor, fair, good, and excellent) were evaluated in Phase 2. Correlations between Matts endoscopic scores as judged by CCE-2 and conventional colonoscopy were calculated. RESULTS: CCE-2 procedure was completed within 8 h in 69% of the patients. The proportion of patients with good or excellent cleansing level was below 50%. However, Matts endoscopic scores determined by CCE-2 showed a strong correlation with scores obtained by conventional colonoscopy (average rho = 0.797). CONCLUSIONS: Although modifications in bowel preparation are needed, CCE-2 might be feasible for assessing the severity of mucosal inflammation in patients with UC.