Ken Kawakami

Bio: Ken Kawakami is an academic researcher from Osaka Medical College. The author has contributed to research in topics: Ulcerative colitis & Colitis. The author has an hindex of 14, co-authored 57 publications receiving 671 citations.

A comparison of the resection rate for cold and hot snare polypectomy for 4–9 mm colorectal polyps: a multicentre randomised controlled trial (CRESCENT study)

Abstract: Objective To investigate the success rate of cold snare polypectomy (CSP) for complete resection of 4–9 mm colorectal adenomatous polyps compared with that of hot snare polypectomy (HSP). Design A prospective, multicentre, randomised controlled, parallel, non-inferiority trial conducted in 12 Japanese endoscopy units. Endoscopically diagnosed sessile adenomatous polyps, 4–9 mm in size, were randomly assigned to the CSP or HSP group. After complete removal of the polyp using the allocated technique, biopsy specimens from the resection margin after polypectomy were obtained. The primary endpoint was the complete resection rate, defined as no evidence of adenomatous tissue in the biopsied specimens, among all pathologically confirmed adenomatous polyps. Results A total of 796 eligible polyps were detected in 538 of 912 patients screened for eligibility between September 2015 and August 2016. The complete resection rate for CSP was 98.2% compared with 97.4% for HSP. The non-inferiority of CSP for complete resection compared with HSP was confirmed by the +0.8% (90% CI −1.0 to 2.7) complete resection rate (non-inferiority p Conclusions The complete resection rate for CSP is not inferior to that for HSP. CSP can be one of the standard techniques for 4–9 mm colorectal polyps. (Study registration: UMIN000018328)

Comparative study of conventional colonoscopy and pan-colonic narrow-band imaging system in the detection of neoplastic colonic polyps: a randomized, controlled trial.

Abstract: Background. Detection and removal of adenomas by colonoscopy is an important means for preventing cancer; however, small adenomas may be missed during colonoscopy. The narrow-band imaging (NBI) system clearly enhances the microvasculature in neoplastic lesions, making it appear as a dark complex. Therefore, the NBI system may improve the detection of colonic neoplasias. However, no randomized, controlled trials have evaluated the efficacy of a pan-colonic NBI system in adenoma detection. We conducted a randomized, controlled trial to determine the efficacy of the pancolonic NBI system in adenoma detection. Methods. Two hundred forty-three patients were randomized, 121 to conventional colonoscopy and 122 to pan-colonic NBI system. Demographics, indication for colonoscopy, and quality of preparation were similar between groups. Results. Extubation time was not significantly different between the conventional colonoscopy and pan-colonic NBI system. The proportions of patients with at least one adenoma and those with multiple adenomas were not significantly different between groups. However, the pan-colonic NBI system significantly increased the total number of adenomas detected (P < 0.05) and the number of diminutive (<5 mm) adenomas detected (P < 0.05). The pan-colonic NBI system allowed detection of more diminutive adenomas in the distal colon than did conventional colonoscopy (P < 0.01), and more patients in the NBI group had at least one diminutive adenoma than in the control group (P < 0.05). Conclusions. The pan-colonic NBI system improves the total number of adenomas detected, including significantly more diminutive adenomas, without prolongation of extubation time. These results indicate that routine use of the NBI system for surveillance of diminutive adenomas may be recommended.

Utility and problems of endoscopic submucosal dissection for early gastric cancer in elderly patients

Abstract: Background and Aim: Endoscopic submucosal dissection (ESD) is reported to be a safe and reliable procedure for the elderly, but these reports could have already had a bias at the time ESD was performed. However, the reports have not clearly stated the criteria of indications. In the present study, we retrospectively elucidated the usefulness and problems of ESD for early gastric cancer in elderly patients (≥ 65 years) in comparison with non-elderly patients. Methods: The subjects were selected from 412 consecutive patients with early gastric cancer (515 lesions) for which ESD was performed between June 2002 and February 2010. The following were used for analysis between groups: pre- and postoperative performance status (PS) of subjects, prevalence rates of pre-existing comorbidities, characteristics of lesions, treatment outcomes, durations of hospitalization, operating times, incidence rates of complications and durations of hospitalization, and postoperative hemorrhage rates, and duration of hospitalization in patients with anticoagulant therapy. Results: Of the lesions in the elderly, four patients (1.0%) were elderly with a PS of 3. The PS increased to six patients (1.6%) after the procedure. None of the non-elderly had a PS of 3 before or after the procedure. The ratio of patients with a pre-existing comorbidity was higher in the elderly than in the non-elderly. There were no differences between the two groups in the characteristics of the lesions, their duration of hospitalization, their operating times, or the incidence rates of complications. However, the elderly with perforations had a significantly longer hospitalization than the comparable non-elderly. The percentage of the patients taking anticoagulant drugs was significantly higher among the elderly. Of the patients on anticoagulant therapy, the duration of hospitalization tended to be longer in the elderly but no significant difference was found. None of the non-elderly with postoperative hemorrhage had received anticoagulant therapy. In the elderly with postoperative hemorrhage, 15.8% of the lesions were in those who had received anticoagulant therapy, indicating a significantly higher percentage of such lesions in the elderly group. Conclusion: We conclude that ESD is useful in elderly patients because there is a similar risk as for the non-elderly if the approach is individualized, and the following are taken into consideration when making the final decision of performing ESD in an elderly patient: patients should have a PS of 0, 1, or 2; determine whether or not anticoagulant therapy can be discontinued and whether or not treatment can be performed reliably without complications.

Simvastatin Attenuates Intestinal Fibrosis Independent of the Anti-Inflammatory Effect by Promoting Fibroblast/Myofibroblast Apoptosis in the Regeneration/Healing Process from TNBS-Induced Colitis

Abstract: Background Intestinal deformity and stenosis are induced by fibrosis during the process healing of intestinal chronic inflammation in inflammatory bowel disease (IBD). Potent anti-inflammatory treatment of patients with Crohn’s disease (CD) may induce fibrous stenosis, and this is often difficult to treat in clinical practice. Therefore, it is necessary to develop a treatment strategy that concomitantly exhibits repair/regenerative and anti-fibrotic effects, in addition to the current anti-inflammatory effect, for the treatment of inflammatory bowel diseases. However, the relationship between the course of inflammatory activity and the healing process and fibrogenesis has not been elucidated; although the complex involvement of various factors in the mechanism of biological fibrosis has been investigated. Simvastatin (SIMV), an HMG-CoA reductase inhibitor, exhibits anti-inflammatory and anti-fibrotic effects. The current study established a model of the regeneration/healing process from TNBS-induced colitis and investigated the anti-inflammatory and anti-fibrotic effects of SIMV.

Proliferative effects of γ‐aminobutyric acid on the gastric cancer cell line are associated with extracellular signal‐regulated kinase 1/2 activation

Abstract: Background and aim Gamma-aminobutyric acid (GABA) is the principal inhibitory neurotransmitter in the adult mammalian brain. However, GABA is found not only in peripheral neuronal tissue, but also in many peripheral non-neuronal tissues, and is thought to have important physiological functions in addition to neurotransmission. We previously reported that GABA participates in chondrocyte proliferation. In the present study, we investigated the effects of GABA on the proliferation of a gastric cancer cell line, KATO III. Methods Reverse transcription polymerase chain reaction and immunohistochemical analyses were performed to examine the expression of the GABA synthesis enzyme, glutamate decarboxylase (GAD), and that of the GABA(A) and GABA(B) receptor subunits. The production of GABA was confirmed by immunohistochemistry. The proliferative effect of GABA on KATO III cells was analyzed by bromodeoxyuridine incorporation assay, and the activation status of mitogen-activated protein (MAP) kinases (extracellular signal-regulated kinase [ERK]-1/2, Jun-N-terminal kinase, and p38) and the expression of cyclin D1 were analyzed by western blotting. Results KATO III cells expressed GAD and GABA. More than five GABA(A) receptor subunits, including the pi subunit, were expressed in KATO III cells; however, GABA(B) receptor subunits were not seen. The addition of GABA to the medium promoted KATO III proliferation, and maximum proliferative effects were observed in the presence of 10 or 1 microM GABA. The addition of 1 microM GABA predominantly activated ERK-1/2 among the three MAP kinases in addition to increasing cyclin D1 expression. Conclusion GABA is able to promote KATO III cell proliferation in an autocrine or a paracrine fashion through GABA(A) receptors followed by MAP kinase activation.

ERK/MAPK signalling pathway and tumorigenesis.

Abstract: Mitogen-activated protein kinase (MAPK) cascades are key signalling pathways that regulate a wide variety of cellular processes, including proliferation, differentiation, apoptosis and stress responses. The MAPK pathway includes three main kinases, MAPK kinase kinase, MAPK kinase and MAPK, which activate and phosphorylate downstream proteins. The extracellular signal-regulated kinases ERK1 and ERK2 are evolutionarily conserved, ubiquitous serine-threonine kinases that regulate cellular signalling under both normal and pathological conditions. ERK expression is critical for development and their hyperactivation plays a major role in cancer development and progression. The Ras/Raf/MAPK (MEK)/ERK pathway is the most important signalling cascade among all MAPK signal transduction pathways, and plays a crucial role in the survival and development of tumour cells. The present review discusses recent studies on Ras and ERK pathway members. With respect to processes downstream of ERK activation, the role of ERK in tumour proliferation, invasion and metastasis is highlighted, and the role of the ERK/MAPK signalling pathway in tumour extracellular matrix degradation and tumour angiogenesis is emphasised.

Advanced imaging for detection and differentiation of colorectal neoplasia: European Society of Gastrointestinal Endoscopy (ESGE) Guideline.

Abstract: This Guideline is an official statement of the European Society of Gastrointestinal Endoscopy (ESGE). It addresses the role of advanced endoscopic imaging for the detection and differentiation of colorectal neoplasia. Main recommendations 1 ESGE suggests the routine use of high definition white-light endoscopy systems for detecting colorectal neoplasia in average risk populations (weak recommendation, moderate quality evidence). 2 ESGE recommends the routine use of high definition systems and pancolonic conventional or virtual (narrow band imaging [NBI], i-SCAN) chromoendoscopy in patients with known or suspected Lynch syndrome (strong recommendation, low quality evidence). 2b ESGE recommends the routine use of high definition systems and pancolonic conventional or virtual (NBI) chromoendoscopy in patients with known or suspected serrated polyposis syndrome (strong recommendation, low quality evidence). 3 ESGE recommends the routine use of 0.1 % methylene blue or 0.1 % – 0.5 % indigo carmine pancolonic chromoendoscopy with targeted biopsies for neoplasia surveillance in patients with long-standing colitis. In appropriately trained hands, in the situation of quiescent disease activity and adequate bowel preparation, nontargeted, four-quadrant biopsies can be abandoned (strong recommendation, high quality evidence). 4 ESGE suggests that virtual chromoendoscopy (NBI, FICE, i-SCAN) and conventional chromoendoscopy can be used, under strictly controlled conditions, for real-time optical diagnosis of diminutive (≤ 5 mm) colorectal polyps to replace histopathological diagnosis. The optical diagnosis has to be reported using validated scales, must be adequately photodocumented, and can be performed only by experienced endoscopists who are adequately trained and audited (weak recommendation, high quality evidence). 5 ESGE suggests the use of conventional or virtual (NBI) magnified chromoendoscopy to predict the risk of invasive cancer and deep submucosal invasion in lesions such as those with a depressed component (0-IIc according to the Paris classification) or nongranular or mixed-type laterally spreading tumors (weak recommendation, moderate quality evidence). Conclusion Advanced imaging techniques will need to be applied in specific patient groups in routine clinical practice and to be taught in endoscopic training programs.