Mikami, Yohei



School of Medicine, Department of Internal Medicine (Gastroenterology and Hepatology) (Shinanomachi)


Associate Professor

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Academic Degrees 【 Display / hide

  • PhD (Medicine), Keio University, Coursework, 2012


Research Keywords 【 Display / hide

  • Inflammatory bowel disease

  • Mucosal immunology

  • Tissue regeneration and fibrosis

  • Neuroimmunology


Papers 【 Display / hide

  • Clinical outcomes of patients with remitting ulcerative colitis after discontinuation of indigo naturalis

    Shimada F., Yoshimatsu Y., Sujino T., Fukuda T., Aoki Y., Hayashi Y., Tojo A., Kawaguchi T., Kiyohara H., Sugimoto S., Nanki K., Mikami Y., Miyamoto K., Takabayashi K., Hosoe N., Kato M., Ogata H., Naganuma M., Kanai T.

    Scientific Reports (Scientific Reports)  14 ( 1 ) 5778 2024.12

    ISSN  2045-2322

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    Indigo naturalis is an effective treatment for ulcerative colitis. However, long-term use of indigo naturalis causes adverse events, such as pulmonary hypertension. The natural history of patients with ulcerative colitis who discontinued indigo naturalis after induction therapy is unknown. Moreover, the clinical features of patients who relapsed within 52 weeks after the discontinuation of indigo naturalis are unclear. This study aimed to assess the clinical outcomes of patients with ulcerative colitis after discontinuation of indigo naturalis and to identify potential markers responsible for relapse. This single-center retrospective study investigated the follow-up of 72 patients who achieved a clinical response 8 weeks after indigo naturalis treatment. We observed relapse in patients with ulcerative colitis after the discontinuation of indigo naturalis. We analyzed the factors predicting long-term outcomes after discontinuation of indigo naturalis. Relapse was observed in 24%, 57%, and 71% of patients at 8, 26, and 52 weeks, respectively. There were no predictive markers in patients who relapsed within 52 weeks after the discontinuation of indigo naturalis. The ulcerative colitis relapse rate after indigo naturalis discontinuation was high. Follow-up treatment is required after the discontinuation of indigo naturalis in patients with ulcerative colitis.

  • A CTCF-binding site in the Mdm1-Il22-Ifng locus shapes cytokine expression profiles and plays a critical role in early Th1 cell fate specification

    Liu C., Nagashima H., Fernando N., Bass V., Gopalakrishnan J., Signorella S., Montgomery W., Lim A.I., Harrison O., Reich L., Yao C., Sun H.W., Brooks S.R., Jiang K., Nagarajan V., Zhao Y., Jung S., Phillips R., Mikami Y., Lareau C.A., Kanno Y., Jankovic D., Aryee M.J., Pękowska A., Belkaid Y., O'Shea J., Shih H.Y.

    Immunity (Immunity)  57 ( 5 ) 1005 - 1018.e7 2024.05

    ISSN  10747613

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    Cytokine expression during T cell differentiation is a highly regulated process that involves long-range promoter-enhancer and CTCF-CTCF contacts at cytokine loci. Here, we investigated the impact of dynamic chromatin loop formation within the topologically associating domain (TAD) in regulating the expression of interferon gamma (IFN-γ) and interleukin-22 (IL-22); these cytokine loci are closely located in the genome and are associated with complex enhancer landscapes, which are selectively active in type 1 and type 3 lymphocytes. In situ Hi-C analyses revealed inducible TADs that insulated Ifng and Il22 enhancers during Th1 cell differentiation. Targeted deletion of a 17 bp boundary motif of these TADs imbalanced Th1- and Th17-associated immunity, both in vitro and in vivo, upon Toxoplasma gondii infection. In contrast, this boundary element was dispensable for cytokine regulation in natural killer cells. Our findings suggest that precise cytokine regulation relies on lineage- and developmental stage-specific interactions of 3D chromatin architectures and enhancer landscapes.

  • Ulcerative colitis-associated neoplasms often harbor poor prognostic histologic components with low detection by biopsy

    Sakakibara, R; Sugimoto, S; Takabayashi, K; Kiyohara, H; Wakisaka, Y; Kaieda, Y; Kawaida, M; Yoshimatsu, Y; Sujino, T; Hosoe, N; Kato, M; Shimoda, M; Mikami, Y; Iwao, Y; Kanai, T


    ISSN  1598-9100

  • Efficacy of Dose Escalation of Oral 5-Aminosalicylic Acid for Ulcerative Colitis With a Mayo Endoscopic Subscore of 1: An Open Label Randomized Controlled Trial

    Fukuda, T; Aoki, Y; Kiyohara, H; Yokoyama, A; Nakazawa, A; Yoshimatsu, Y; Sugimoto, S; Nanki, K; Mikami, Y; Fukuhara, K; Mizuno, S; Sujino, T; Mutaguchi, M; Takabayashi, K; Morohoshi, Y; Hosoda, Y; Ogata, H; Iwao, Y; Naganuma, M; Kanai, T


    ISSN  1078-0998

  • Video capsule endoscopy in overt and occult obscure gastrointestinal bleeding: Insights from a single-center, observational study in Japan

    Tojo A., Sujino T., Hayashi Y., Kamiya K.J.L.L., Sato M., Hinako S., Yoshimatsu Y., Kinoshita S., Kiyohara H., Mikami Y., Takabayashi K., Kato M., Ogata H., Kanai T., Hosoe N.

    DEN Open (DEN Open)  4 ( 1 ) e354 2024.04

    ISSN  2692-4609

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    Objective: This study aimed to evaluate the use of video capsule endoscopy (VCE) in patients with obscure gastrointestinal bleeding (OGIB), compare cases of overt and occult OGIB, assess the rates of balloon-assisted enteroscopy (BAE) interventions and rebleeding, and identify predictive markers of positive VCE findings. Methods: Medical records of 430 patients who underwent VCE for OGIB between 2004 and 2022 were analyzed. Occult OGIB was defined as IDA or positive fecal occult blood, whereas overt OGIB was defined as clinically imperceptible bleeding. We retrospectively analyzed demographics, VCE findings based on Saurin classification (P0, P1, and P2), outcome of BAE interventions, and rebleeding rates. Results: A total of 253 patients with overt OGIB and 177 with occult OGIB were included. P1 findings were predominant in both groups, with a similar distribution. The percentage of patients receiving conservative therapy was higher in P1 than in P2 for both overt and occult OGIB. BAE was more frequently performed in P2 than in P1 VCE (83.0% vs. 35.3% in overt OGIB, 84.4% vs. 24.4% in occult OGIB). The percentage of positive findings and intervention in total BAE performed patients were comparable in P1 and P2 of overt OGIB, whereas these percentages in P2 were more than P1 of occult OGIB. Conclusion: VCE effectively identified OGIB lesions requiring intervention, particularly occult OGIB lesions, potentially reducing unnecessary BAE. Rebleeding rates varied according to the VCE findings, emphasizing the importance of follow-up in high-risk patients.

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Papers, etc., Registered in KOARA 【 Display / hide

Reviews, Commentaries, etc. 【 Display / hide

  • Correction: Association of ulcerative colitis symptom severity and proctocolectomy with multidimensional patient-reported outcomes: a cross-sectional study(Journal of Gastroenterology, (2023), 58, (751–765), 10.1007/s00535-023-02005-7)

    Matsuoka K., Yamazaki H., Nagahori M., Kobayashi T., Omori T., Mikami Y., Fujii T., Shinzaki S., Saruta M., Matsuura M., Yamamoto T., Motoya S., Hibi T., Watanabe M., Fernandez J., Fukuhara S., Hisamatsu T.

    Journal of Gastroenterology (Journal of Gastroenterology)   2024

    ISSN  09441174

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    Fig. 2h of the original article contained extraneous yellow data bars; Fig. 2h should appear as shown in this correction. (Figure presented.) Proportion of patients reporting a QOL as low, normal or high on SIBDQ; b severe fatigue on FACIT-F; c depression or d anxiety on the HADS scale; e absenteeism, f presenteeism, g work productivity, and h activity impairment on WPAI; and i poor sleep quality on PSQI. FACIT-F Functional Assessment of Chronic Illness Therapy – Fatigue, HADS Hospital Anxiety and Depression Scale, PSQI Pittsburgh Sleep Quality Index, QOL quality of life, SIBDQ Short Inflammatory Bowel Disease Questionnaire, WPAI Work Productivity and Activity Impairment In Fig. 3 of the original article, the labelling of ‘y’ axis was reversed (i.e., better/worse outcome); Fig. 3 should appear as shown in this correction. (Figure presented.) Associations of symptom severity and proctocolectomy with patient-reported outcomes. Data indicate SMD and their 95% confidence intervals. The fraction of variance of symptom severity explained by each outcome is shown in parentheses. The magnitude of the effect size was interpreted as: small, SMD = 0.2; medium, SMD = 0.5; and large, SMD = 0.8 [39]. Total number of patients included in the analysis were: SIBDQ (N = 1956), FACIT-F (N = 1935), HADS-D (N = 1958), HADS-A (N = 1958), WPAI-A (N = 1346), WPAI-P (N = 1346), WPAI-L (N = 1346), WPAI-I (N = 1909), and PSQI (N = 1917) (see Table 3 footnotes for breakdown by patient group). FACIT-F Functional Assessment of Chronic Illness Therapy – Fatigue, HADS Hospital Anxiety and Depression Scale (A, anxiety; D, depression), PSQI Pittsburgh Sleep Quality Index, SIBDQ Short Inflammatory Bowel Disease Questionnaire, SMD standardized mean difference, WPAI Work Productivity and Activity Impairment (A, absenteeism; I, impairment of activity; L, loss of productivity; P, presenteeism)

  • A second update on mapping the human genetic architecture of COVID-19

    Kanai M., Andrews S.J., Cordioli M., Stevens C., Neale B.M., Daly M., Ganna A., Pathak G.A., Iwasaki A., Karjalainen J., Mehtonen J., Pirinen M., Chwialkowska K., Trankiem A., Balaconis M.K., Veerapen K., Wolford B.N., Ahmad H.F., von Hohenstaufen Puoti K.A., Boer C., Boua P.R., Butler-Laporte G., Cadilla C.L., Colombo F., Douillard V., Dueker N., Dutta A.K., El-Sherbiny Y.M., Eltoukhy M.M., Esmaeeli S., Faucon A., Fave M.J., Cadenas I.F., Francescatto M., Francioli L., Franke L., Fuentes M., Durán R.G., Cabrero D.G., Harry E.N., Jansen P., Szentpéteri J.L., Kaja E., Kirk C., Kousathanas A., Krieger J.E., Patel S.K., Lemaçon A., Limou S., Lió P., Marouli E., Marttila M.M., Medina-Gómez C., Michaeli Y., Migeotte I., Mondal S., Moreno-Estrada A., Moya L., Nakanishi T., Nasir J., Pasko D., Pearson N.M., Pereira A.C., Priest J., Prijatelj V., Prokic I., Teumer A., Várnai R., Romero-Gómez M., Roos C., Rosenfeld J., Ruolin L., Schulte E.C., Schurmann C., Sedaghati-khayat B., Shaheen D., Shivanathan I., Sipeky C., Sirui Z., Striano P., Tanigawa Y., Remesal A.U., Vadgama N., Vallerga C.L., van der Laan S., Verdugo R.A., Wang Q.S., Wei Z., Zainulabid U.A., Zárate R.N., Auton A., Shelton J.F., Shastri A.J., Weldon C.H., Filshtein-Sonmez T., Coker D., Symons A.

    Nature (Nature)  621 ( 7977 ) E7 - E26 2023.09

    ISSN  00280836

  • Correction: Characteristics of adult patients newly diagnosed with Crohn’s disease: interim analysis of the nation-wide inception cohort registry study of patients with Crohn’s disease in Japan (iCREST-CD) (Journal of Gastroenterology, (2022), 57, 11, (867-878), 10.1007/s00535-022-01907-2)

    Matsuoka K., Fujii T., Okamoto R., Yamada A., Kunisaki R., Matsuura M., Watanabe K., Shiga H., Takatsu N., Bamba S., Mikami Y., Yamamoto T., Shimoyama T., Motoya S., Torisu T., Kobayashi T., Ohmiya N., Saruta M., Matsuda K., Matsumoto T., Nakase H., Maemoto A., Shinzaki S., Murata Y., Yoshigoe S., Sasaki A., Yajima T., Hisamatsu T., Nagahori M., Yukawa T., Saito D., Kawai M., Masamune A., Nagasaka M., Kazama T.

    Journal of Gastroenterology (Journal of Gastroenterology)  58 ( 6 ) 602 - 603 2023.06

    ISSN  09441174

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    In the original publication, ‘‘iCREST-CD Study Group’’ was not included in the author list. The correct author list is included in this Correction. Also, an Appendix listing iCREST-CD Study Group collaborators is included in this correction.

  • Correction to: Expert consensus on vaccination in patients with inflammatory bowel disease in Japan (Journal of Gastroenterology, (2023), 58, 2, (135-157), 10.1007/s00535-022-01953-w)

    Ishige T., Shimizu T., Watanabe K., Arai K., Kamei K., Kudo T., Kunisaki R., Tokuhara D., Naganuma M., Mizuochi T., Murashima A., Inoki Y., Iwata N., Iwama I., Koinuma S., Shimizu H., Jimbo K., Takaki Y., Takahashi S., Cho Y., Nambu R., Nishida D., Hagiwara S.i., Hikita N., Fujikawa H., Hosoi K., Hosomi S., Mikami Y., Miyoshi J., Yagi R., Yokoyama Y., Hisamatsu T.

    Journal of Gastroenterology (Journal of Gastroenterology)  58 ( 4 ) 431 - 432 2023.04

    ISSN  09441174

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    The article ‘‘Expert consensus on vaccination in patients with inflammatory bowel disease in Japan’’, written by Takashi Ishige, Toshiaki Shimizu, Kenji Watanabe, Katsuhiro Arai, Koichi Kamei, Takahiro Kudo, Reiko Kunisaki, Daisuke Tokuhara, Makoto Naganuma, Tatsuki Mizuochi, Atsuko Murashima, Yuta Inoki, Naomi Iwata, Itaru Iwama, Sachi Koinuma, Hirotaka Shimizu, Keisuke Jimbo, Yugo Takaki, Shohei Takahashi, Yuki Cho, Ryusuke Nambu, Daisuke Nishida, Shin-ichiro Hagiwara, Norikatsu Hikita, Hiroki Fujikawa, Kenji Hosoi, Shuhei Hosomi, Yohei Mikami, Jun Miyoshi, Ryusuke Yagi, Yoko Yokoyama, Tadakazu Hisamatsu, was originally published electronically on the publisher’s internet portal on 11 January 2023 without open access. With the author(s)’ decision to opt for Open Choice the copyright of the article changed on 17 January 2023 to © The Author(s) 2023 and the article is forthwith distributed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

  • Epithelium Replacement Contributes to Field Expansion of Squamous Epithelium and Ulcerative Colitis–Associated Neoplasia

    Sugimoto S., Iwao Y., Shimoda M., Takabayashi K., Sato T., Kanai T., Mutaguchi M., Nanki K., Okabayashi K., Kawaida M., Aoki Y., Yoshimatsu Y., Kiyohara H., Kawaguchi T., Mikami Y., Fukuhara K., Sujino T., Hosoe N., Ogata H., Yahagi N.

    Gastroenterology (Gastroenterology)  162 ( 1 ) 334 - 337.e5 2022.01

    ISSN  00165085

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Presentations 【 Display / hide


    Puchner, Antonia, Saferding, Victoria, Bonelli, Michael, Mikami, Yohei, Goncalves-Alves, Eliana, Binder, Nikolaus B., Steiner, Carl-Walter, Hayer, Silvia, Niederreiter, Birgit, Koenders, Marije M., Smolen, Josef S., Redlich, Kurt, Bluml, Stephan



Research Projects of Competitive Funds, etc. 【 Display / hide

  • 自己免疫疾患スペクトラムを誘発する宿主免疫・腸内細菌叢相互作用の包括的理解


    Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), No Setting

  • 宿主侵入菌に対する腸肝脳相関の解明と消化器免疫難病の治療開発


    Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), No Setting

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  • Elucidation of the entropy of tissue damage in digestive organs and development of new therapeutic approaches


    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Transformative Research Areas (B), Principal investigator

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    腸管組織常在細胞のうち、まず腸管ストローマ細胞に着目して研究を開始した。本年度は、マウスの腸管検体および、およびヒト患者より供与いただいた腸管切除検体を、ストローマ細胞集団をFACSにより単離、1細胞遺伝子発現解析を行った。得られたデータを既に研究室内で確立している解析pipelineを用いて検討を行ったところ、従来広義の線維芽細胞の定義であるVimentin + Desmin -集団の中には、線維芽細胞の他にもグリア細胞、血管周皮細胞、平滑筋細胞など多様な集団が存在していることが明らかとなった。さらに解析を進め、腸管局所における線維芽細胞の多様性とマウス・ヒト間での相同性および相違性を明らかとした。

  • 炎症性組織レジリエンスと組織障害エントロピーの統合的理解と炎症収束学の創成


    Grants-in-Aid for Scientific Research, Grant-in-Aid for Transformative Research Areas (B), No Setting

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    また、2022年1月には、平原班が中心となり、「炎症収束の理解による新たな治療創生 -難治性疾患の克服にむけて-」と銘打ってハイブリッド形式のシンポジウムを開催した。
    研究支援システムの整備(担当:平原):研究班内での研究の有機的連携を行うため、single cell RNA-Seq解析支援、網羅的エピゲノム解析(ChIP-Seq, ATAC-Seq)解析支援、バイオイメージング解析支援のための整備を行う。
    領域会議・国際シンポジウムの開催(担当:新井):年1回の領域会議を開催し、領域内の研究進歩状況を把握し、それぞれの研究成果を共有するとともに、研究班員間の共同研究につなげ有機的連携を推し進めていく。会議には若手研究者の参加を推奨し、若手の育成を図る。令和3, 4年度には国際シンポジウムを開催し、若手を中心とした海外研究者を招聘し、交流を図るとともに研究成果を国際的に発信する。

  • Gene regulation in the gut T cells and IBD


    MEXT,JSPS, Grant-in-Aid for Scientific Research, Mikami Yohei, Grant-in-Aid for Scientific Research (B), Principal investigator

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    Th17 cell, which is defined as the IL-17 producing T helper cell, has been reported to contribute to the pathogenesis of inflammatory bowel disease (IBD). Comprehensive analyses of global microRNA expression in haematopoietic cells identified miRNA-221/2, which is highly expressed in Th1 and Th17 cells involved in intestinal inflammation and poorly expressed in cells not involved in inflammation such as Naive T cells and regulatory T cells. In addition, we reported the regulatory mechanism of gene expression of miRNA-221/2 and their biological significance in intestinal inflammation.

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Awards 【 Display / hide

  • 日本免疫学会研究奨励賞


  • 慶應医学賞 ライジング・スター賞


    Type of Award: Keio commendation etc.

  • 第55回日本消化器免疫学会総会 奨励賞


    Type of Award: Award from Japanese society, conference, symposium, etc.

  • NIH Group Merit Award


  • 三四会奨励賞

    2011, Keio University School of Medicine, Sanshikai

    Type of Award: Keio commendation etc.


Courses Taught 【 Display / hide











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