Keitaro Takahashi

Dr. Keitaro Takahashi


Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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Verified
Journal Article
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KTKeitaro Takahashi
Keitaro Takahashi
MFMikihiro Fujiya
Mikihiro Fujiya
HKHiroaki Konishi
Hiroaki Konishi
YMYuki Murakami
Yuki Murakami
TITakuya Iwama
Takuya Iwama
TOToshikatsu Okumura
Toshikatsu Okumura
The oncogenic properties of heterogeneous nuclear ribonucleoprotein H1 (hnRNP H1) have been reported, although the tumor-promoting mechanism remains unclear. We herein report the mechanism underlying colorectal cancer cell progression mediated by hnRNP H1. The growth of colorectal cancer cells was suppressed by hnRNP H1 downregulation. A terminal deoxynucleotidyl transferase dUTP nick-end labeling assay revealed the anti-apoptotic effect of hnRNP H1 in colorectal cancer cells. An RNA immunoprecipitation assay revealed that hnRNP H1 bound to sphingosine-1-phosphate lyase 1 (SGPL1). Reverse transcription-polymerase chain reaction revealed the high expression of hnRNP H1 mRNA in colorectal cancer cells and Spearman’s rank correlation coefficient showed a strong positive correlation between hnRNP H1 mRNA and SGPL1 mRNA. An siRNA of hnRNP H1 decreased SGPL1 mRNA expression in colorectal cancer cells, but not in non-tumorous cells. These findings suggested that hnRNP H1 increased SGPL1 mRNA expression specifically in cancer cells through direct binding. Targeted knockdown of hnRNP H1 or SGPL1 with siRNAs upregulated p53 phosphorylation and p53-associated molecules, resulting in cell growth inhibition, while hnRNP H1 upregulated the mRNA of SGPL1 and inhibited p53 activation, thereby promoting tumor cell growth. This is a novel mechanism underlying colorectal cancer cell progression mediated by hnRNP H1–SGPL1 mRNA stabilization.

22 May 2024 in Digestion
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Journal Article
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KTKeitaro Takahashi
Keitaro Takahashi
TITakuya Iwama
Takuya Iwama
KTKazuyuki Tanaka
Kazuyuki Tanaka
YMYuki Miyazawa
Yuki Miyazawa
SKShohei Kuroda
Shohei Kuroda
MFMikihiro Fujiya
Mikihiro Fujiya
Introduction: Carbazochrome sodium sulfonate (CSS) is a hemostatic agent that reduces capillary permeability and enhances capillary resistance. However, its specific effects on colorectal endoscopic submucosal dissection (ESD) outcomes remain uncertain. This study aimed to assess the risk factors for post-ESD bleeding and the effect of CSS on colorectal ESD outcomes. Methods: First, we retrospectively analyzed the risk factors for post-ESD bleeding using data from 1,315 lesions in 1,223 patients who underwent ESD for superficial colorectal neoplasms at eight institutions. Second, patients were divided into CSS and non-CSS groups using propensity score matching, and their outcomes from colorectal ESD were analyzed. Results: The risk factors for post-colorectal ESD bleeding were identified as age of ≥70 years, tumor located in the rectum, tumor size of ≥40 mm, and post-ESD defect unclosure in both univariate and multivariate analyses. The CSS and non-CSS groups each consisted of 423 lesions after propensity score matching. The post-colorectal ESD bleeding rate was 3.5% (15/423) and 3.3% (14/423) in the CSS and non-CSS groups, respectively, indicating no significant differences. Among patients with the high-risk factors for post-ESD bleeding, the administration of CSS also did not demonstrate a significant reduction in the post-ESD bleeding rate compared to the non-CSS group. Conclusion: CSS administration is ineffective in preventing post-colorectal ESD bleeding in both the general population and individuals at a high risk for such bleeding. Our results indicate the necessity to reconsider the application of CSS for preventing post-colorectal ESD bleeding.

14 July 2023 in Medicine
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Journal Article
Open access
YSYuya Sugiyama
Yuya Sugiyama
NUNobohiro Ueno
Nobohiro Ueno
STShion Tachibana
Shion Tachibana
YKYu Kobayashi
Yu Kobayashi
YMYuki Murakami
Yuki Murakami
MFMikihiro Fujiya
Mikihiro Fujiya
Rationale: Latent tuberculosis (TB) infection screening before inducing anti-tumor necrosis factor (anti-TNF) alpha agents is important to prevent TB reactivation. However, latent TB infection reactivation may still occur, and the ideal therapeutic strategy for patients with inflammatory bowel disease (IBD) who develop active TB infection has not been established. Vedolizumab (VDZ) has a good safety profile, with low incidence rates of serious infections. However, its safety in patients with latent TB infection reactivation associated with anti-TNF-alpha agents remains unknown. Patient concerns: A 21-year-old Vietnamese male patient presented to our hospital with hemorrhagic stool. He had no personal or family history of IBD or TB. Diagnoses: Colonoscopy revealed multiple longitudinal ulcers and a cobblestone appearance in the terminal ileum, as well as multiple small erosions and aphtha throughout the colon. Computed tomography revealed a right lung nodular lesion. Serological interferon-gamma release assay and several culture tests were all negative. Thus, he was diagnosed with ileocolonic Crohn’s disease (CD) without TB. Interventions: The intravenous anti-TNF-alpha agent administration with an immunomodulator was initiated. Outcomes: Computed tomography revealed nodular lesion expansion at the right lung, and serological interferon-gamma release assay was positive. He was diagnosed with latent TB infection reactivation. Anti-TNF-alpha agent with an immunomodulator was immediately discontinued, and anti-TB therapy was initiated. His endoscopic findings were still active, and VDZ was selected for maintenance therapy because VDZ has a favorable safety profile with low incidence rates of serious infections. Consequently, mucosal healing was achieved without active TB relapse. Lessons: This case report presented a patient in whom VDZ was continued as maintenance therapy without inducing TB relapse in a patient with CD who developed latent TB infection reactivation associated with anti-TNF-alpha agents and summarized the safety profile of VDZ for patients with IBD with active or latent TB infection. VDZ may be a safe option for induction and maintenance therapy in patients with CD, even in cases with latent TB infection reactivation.

20 March 2019 in Molecules
Verified
Journal Article
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KMKentaro Moriichi
Kentaro Moriichi
MFMikihiro Fujiya
Mikihiro Fujiya
YKYu Kobayashi
Yu Kobayashi
YMYuki Murakami
Yuki Murakami
TITakuya Iwama
Takuya Iwama
TOToshikatsu Okumura
Toshikatsu Okumura
Background: Autofluorescence imaging (AFI) is useful for diagnosing colon neoplasms, but what affects the AFI intensity remains unclear. This study investigated the association between AFI and the histological characteristics, aberrant methylation status, and aberrant expression in colon neoplasms. Methods: Fifty-three patients with colorectal neoplasms who underwent AFI were enrolled. The AFI intensity (F index) was compared with the pathological findings and gene alterations. The F index was calculated using an image analysis software program. The pathological findings were assessed by the tumor crypt density, cell densities, and N/C ratio. The aberrant methylation of p16, E-cadherin, Apc, Runx3, and hMLH1 genes was determined by a methylation-specific polymerase chain reaction. The aberrant expression of p53 and Ki-67 was evaluated by immunohistochemical staining. Results: An increased N/C ratio, the aberrant expression of p53, Ki-67, and the altered methylation of p16 went together with a lower F index. The other pathological findings and the methylation status showed no association with the F index. Conclusions: AFI reflects the nuclear enlargement of tumor cells, the cell proliferation ability, and the altered status of cell proliferation-related genes, indicating that AFI is a useful and practical method for predicting the dysplastic grade of tumor cells and cell proliferation.

7 March 2022 in Surgical Endoscopy
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Journal Article
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KTKeitaro Takahashi
Keitaro Takahashi
TSTakahiro Sasaki
Takahiro Sasaki
NUNobuhiro Ueno
Nobuhiro Ueno
KUKyoko Uehara
Kyoko Uehara
YKYu Kobayashi
Yu Kobayashi
MFMikihiro Fujiya
Mikihiro Fujiya
Background: Carbazochrome sodium sulfonate (CSS) is conventionally administered to prevent post-endoscopic submucosal dissection (ESD) bleeding in many institutions, but research on its preventive efficacy is lacking. Therefore, we investigated the risk of post-ESD bleeding and the preventive efficacy of CSS administration. Methods: We retrospectively reviewed 304 lesions in 259 patients with gastric neoplasms who underwent ESD at Asahikawa Medical University Hospital from 2014 to 2021. In the CSS group, CSS 100 mg/day was intravenously infused with maintenance fluid replacement on postoperative days 0–2. The risk factors of post-ESD bleeding, including CSS administration, were investigated. Results: The overall rate of post-ESD bleeding was 4.6% (14/304). The univariate analysis showed that atrial fibrillation (Af), warfarin intake, heparin replacement, and tumor location in the lower third were significant risk factors for increasing the likelihood of postoperative bleeding. In the multivariate analysis, Af (odds ratio [OR] 3.83, 95% CI 1.02–14.30; p < 0.05), heparin replacement (OR 4.60, 95% CI 1.02–20.70; p < 0.05), and tumor location in the lower third of the stomach (OR 6.67, 95% CI 1.43–31.00; p < 0.05) were independent factors for post-ESD bleeding. Post-ESD bleeding was observed in 5.2% (9/174) of the CSS group and 3.8% (5/130) of the non-CSS group, with no significant difference between the two groups (p = 0.783). Additionally, CSS was not shown to have preventive effects in groups with higher-risk factors, such as Af diagnosis, warfarin use, heparin replacement, and tumor location in the lower third of the stomach. Conclusion: CSS administration was not effective for the prevention of the post-ESD bleeding in the overall patient population as well as in higher-risk patients. This suggests that the administration of CSS for post-ESD bleeding prevention may need to be reconsidered.

14 July 2022 in Endoscopy
Verified
Journal Article
Open access
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KTKeitaro Takahashi
Keitaro Takahashi
YMYuki Murakami
Yuki Murakami
TSTakahiro Sasaki
Takahiro Sasaki
NUNobuhiro Ueno
Nobuhiro Ueno
STShion Tachibana
Shion Tachibana
MFMikihiro Fujiya
Mikihiro Fujiya
Background Transnasal endoscopy presents a technical difficulty when inserting the flexible endoscope. It is unclear whether a particular breathing method is useful for transnasal endoscopy. Therefore, we conducted a prospective randomized controlled trial to compare endoscopic operability and patient tolerance between patients assigned to nasal breathing or oral breathing groups.Methods 198 eligible patients were randomly assigned to undergo transnasal endoscopy with nasal breathing or with oral breathing. Endoscopists and patients answered questionnaires on the endoscopic operability and patient tolerance using a 100-mm visual analog scale ranging from 0 (non-existent) to 100 (most difficult/unbearable). The visibility of the upper-middle pharynx was recorded.Results Patient characteristics did not differ significantly between the groups. Nasal breathing showed a higher rate of good visibility of the upper-middle pharynx than oral breathing (91.9 % vs. 27.6 %; P < 0.001). Nasal breathing showed lower mean [SD] scores than oral breathing in terms of overall technical difficulty (21.0 [11.4] vs. 35.4 [15.0]; P < 0.001). Regarding patient tolerance, nasal breathing showed lower scores than oral breathing for overall discomfort (22.1 [18.8] vs. 30.5 [20.9]; P = 0.004) and other symptoms, including nasal and throat pain, choking, suffocating, gagging, belching, and bloating (all P < 0.05). The pharyngeal bleeding rate was lower in the nasal breathing group than in the oral breathing group (0 % vs. 9.2 %; P = 0.002).Conclusions Nasal breathing is superior to oral breathing for those performing and undergoing transnasal endoscopy. Nasal breathing led to good visibility of the upper-middle pharynx, improved endoscopic operability, and better patient tolerance, and was safer owing to decreased pharyngeal bleeding.