KEIO RESEARCHERS INFORMATION SYSTEM

Licenses and Qualifications 【 Display / hide 】

Licenses and Qualifications 【 Display / hide 】

• 医師免許証, 2000.04

Research Areas 【 Display / hide 】

Research Areas 【 Display / hide 】

• Life Science / Orthopedics

Papers 【 Display / hide 】

Papers 【 Display / hide 】

• Enhanced nerve regeneration after transplantation of NCAM-positive neural crest-like cells derived from human iPSC

  Amemiya T., Ouchi T., Kimura H., Okuyama K., Phan T.Q., Iwamoto T., Nakagawa T., Matsumoto M., Nakamura M., Okano H., Nagoshi N., Shibata S.

  Inflammation and Regeneration 46 ( 1 )  2026.12

  ISSN  18809693

  　View Summary

  Background: Peripheral nerve injuries often cause persistent sensory and motor deficits, and autologous nerve grafting, the current standard, is limited by donor site morbidity and tissue availability. Human induced pluripotent stem cells (hiPSCs)-derived neural crest-like cells (NCLCs) have shown potential for nerve regeneration, but achieving high purity and safety remains a challenge. Methods: Using a mouse model of large sciatic nerve defects, we evaluated the efficacy of transplanting NCLCs triple-positive for low-affinity nerve growth factor receptor (LNGFR), thymocyte antigen 1 (THY-1), and neural cell adhesion molecule (NCAM). Purified triple-positive cells induced from hiPSC-derived neural crest lineage were seeded in the conduit with collagen gel in the transplantation group and compared the regeneration with the autograft group and the negative control group without cells. Results: NCAM-positive NCLCs promoted robust angiogenesis and recruited host Schwann cells, thereby establishing a supportive regenerative microenvironment. This facilitated axonal regrowth, thick myelination, and organized nerve architecture comparable to that of autografts. Functional recovery, assessed by electrophysiological conduction and motor performance, eventually matched autografts, with earlier improvement observed in the transplantation group. No tumor formation was detected, and the proliferative activity of transplanted cells declined over time. Selective marker-based purification likely contributed to the favorable safety profile. Conclusion: NCAM-positive NCLCs derived from hiPSCs enhance peripheral nerve regeneration through vascularization and Schwann cell-mediated remyelination, resulting in structural and functional recovery equivalent to autografts. This strategy offers a safe, scalable alternative to donor nerve harvest, and integration with bioengineered conduits could further expand clinical applicability in peripheral nerve reconstruction.

  • Access to Document (DOI)

• Anatomical Reconstruction of the Terminal Tendon and Lateral Band for Severe Chronic Tendon Mallet Injury

  Suzuki T., Kiyota Y., Matsumura N., Sato K., Nakamura M., Iwamoto T.

  Journal of Hand Surgery 51 ( 1 ) 92 - 92.e7 2026.01

  ISSN  03635023

  　View Summary

  Purpose This study aimed to evaluate the clinical outcomes of surgical treatment for chronic mallet injury with severe extension lag using an anatomic reconstruction of the terminal tendon and lateral band with a palmaris longus (PL) tendon graft. Methods Eleven patients with a mean age of 52 years (range, 24–82 years) who underwent surgical reconstruction for chronic tendon mallet injuries using the PL tendon were included. The harvested PL tendon was either folded longitudinally or divided into two slips. The graft was secured to the distal phalanx using a bone anchor and sutured to the soft tissues and remnants of the original terminal tendon distal to the distal interphalangeal (DIP) joint. Each half-slip tendon was passed under the transverse retinacular ligament and sutured side-to-side to the lateral band at approximately the midpoint of the proximal phalanx. The active range of motion of the affected finger was evaluated before and after surgery, and any complications were recorded. Results Before surgery, the extension of the DIP joint averaged −49.5° (range, −40° to −60°). The postoperative mean lag of the DIP joint improved to −7.8° (range, −20° to +20°). According to the Miller classification, four patients had excellent results, four had good results, and three had fair results. Two patients who underwent folded-PL tendon grafting developed superficial dorsal skin infections on the little finger that resolved with oral antibiotics or removal of the sutures. Conclusions Anatomical reconstruction of the terminal tendon and lateral bands using a PL tendon graft yielded satisfactory outcomes in chronic tendon mallet injuries. Dividing the PL tendon into two slips is recommended to reduce the risk of postoperative infection. Type of study/level of evidence Therapeutic IV.

  • Access to Document (DOI)

• Platelet-like cells differentiated from adipose-derived mesenchymal stem cells inhibit acute inflammation of tendinopathy in rats

  Torii A., Yamada Y., Ono-Uruga Y., Sato Y., Kaneko Y., Nakamura S., Iwamoto T., Matsubara Y., Matsumoto M., Nakamura M., Sato K., Miyamoto T.

  Journal of Bone and Mineral Metabolism 44 ( 1 ) 18 - 27 2026.01

  ISSN  09148779

  　View Summary

  Introduction: Tendinopathy, a disease that causes inflammation and pain and limits patients’ activities of daily living, is considered particularly important to treat during the acute inflammatory phase to prevent the transition to chronic degeneration. Recently, platelet-rich plasma (PRP) has been used to treat tendinopathy; however, it is not clear whether platelets themselves, which are the active component of PRP, could be effective in treating tendinopathy. Materials and Methods: We made rat Achilles tendinopathy models by incision of the calcaneal attachment and administrated platelet-like cells derived from adipose-derived mesenchymal stem cells (ASCL-PLCs) to the injury site and investigated the anti-inflammatory effect. Results: ASCL-PLCs significantly inhibits the inflammatory cytokine expression and inflammatory cell infiltration in acute tendonitis in a rat Achilles tendon injury model in vivo. Interestingly, we observed no xeno-reaction when human-derived ASCL-PLCs were administered to wild-type rats in vivo. Moreover, IL-6 expression and phosphorylation seen in NIH3T3 fibroblasts treated with IL-6 plus soluble IL-6 receptor were both significantly suppressed by ASCL-PLCs in vitro. Conclusion: ASCL-PLC has advantages over existing PRP therapies, including the ability to be cryopreserved after quality checks, and homogeneous populations of ASCL-PLCs can be prepared in large quantity. We conclude that in the future ASCL-PLCs may serve as an allogeneic transplant effective to treat tendinopathy.

  • Access to Document (DOI)

• Accuracy of Implant Placement Using Augmented Reality–assisted Technique in Total Wrist Arthroplasty

  Watanabe S., Iwamoto T., Tanji A., Kiyota Y., Suzuki T., Nagura T., Nakamura M.

  Journal of Hand Surgery 51 ( 4 ) 371 - 381 2026

  ISSN  03635023

  　View Summary

  Purpose The study aimed to evaluate the accuracy of augmented reality–assisted total wrist arthroplasty (AR-TWA) in a cadaveric model using a three-point registration method. The hypothesis is that AR-assisted surgery can enable surgeons to achieve accurate implant placement comparable with surgeries performed under specialist guidance. Methods Fourteen fresh-frozen upper extremities from seven cadavers were used for TWA. Computed tomography data were imported into three-dimensional image analysis software for surgical planning. On one side, AR-TWA was performed by a board-certified orthpaedic surgeon with no clinical experience in TWA, and on the contralateral side, non–AR-TWA was performed by the same surgeon under the guidance of an experienced hand surgeon. The accuracy of implant placement was assessed by comparing preoperative and postoperative computed tomography scans and measuring deviations and angular errors between the planned and actual component positions. Results For both the radial and carpal components, four of six parameters demonstrated smaller errors in the AR-TWA. Although certain parameters favored the non–AR-TWA, overall variability was lower with AR. When classified as acceptable or outlier, all seven radial cases in the AR-TWA were acceptable for deviation, and six were acceptable for angular error, indicating better consistency than the non–AR-TWA. On the carpal side, AR-TWA demonstrated higher accuracy than non–AR-TWA, but more outliers were observed, suggesting relatively greater variability in this region. Conclusions Augmented reality–assisted TWA using a three-point registration method improved the accuracy of implant placement, even when performed by a less experienced surgeon. Clinical relevance Augmented reality technology may assist less experienced surgeons in performing technically demanding procedures, such as TWA, with improved accuracy.

  • Access to Document (DOI)

• Delayed diagnosis of psoriatic arthritis presenting with infection-like finger inflammation: A case report

  Takahashi S., Kiyota Y., Iwamoto T., Torii A., Oki S., Suzuki T., Matsumura N., Nakamura M.

  Modern Rheumatology Case Reports 10 ( 1 )  2026

  　View Summary

  Psoriatic arthritis is a chronic inflammatory disease associated with psoriasis, and its diagnosis can be challenging owing to nonspecific symptoms, absence of reliable biomarkers, and occasional delay in skin manifestations. Herein, we report a case of psoriatic arthritis that initially presented as an acute finger inflammation mimicking infection. A 46-year-old woman developed sudden swelling and pain in the left ring finger during chemotherapy for cervical cancer. Based on the results of the physical examination, laboratory tests, and magnetic resonance imaging, pyogenic flexor tenosynovitis was suspected, and synovectomy was performed; however, bacterial and mycobacterial cultures yielded negative results. Despite the administration of antibiotics, the inflammation persisted, and she was referred to the Rheumatology Department, where she was diagnosed with reactive arthritis secondary to Chlamydia infection. Although the inflammation improved after antimicrobial therapy, the finger swelling persisted. Follow-up magnetic resonance imaging and serological testing were performed, and the patient was diagnosed with seronegative rheumatoid arthritis. Four years after onset, erythematous skin lesions appeared, and dermatological evaluation confirmed plaque psoriasis; thus, a definitive diagnosis of psoriatic arthritis was established. Disease-modifying antirheumatic drug adjustments improved symptoms, but residual ‘pencil-in-cup’ deformity and limited finger motion remained. This case highlights the difficulty in diagnosing psoriatic arthritis when arthritis precedes skin lesions. Clinicians should consider psoriatic arthritis in persistent or refractory arthritis and carefully monitor skin and nail changes to achieve an earlier diagnosis and prevent irreversible joint damage.

  • Access to Document (DOI)

display all >>

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

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

• Pathophysiology of heterotopic ossification and search for novel therapies.

  Iwamoto, Takuji

  科学研究費補助金研究成果報告書 2023

• Development of 3D printing orthosis based on CT images for finger osteoarthritis

  Iwamoto, Takuji

  科学研究費補助金研究成果報告書 2020

• The establishment of computer assisted surgery for total elbow arthroplasty

  Iwamoto, Takuji

  科学研究費補助金研究成果報告書 2017

• Detection of specific antibody in patients with rheumatoid arthritis negative for anti-CCP antibody

  Iwamoto, Takuji

  科学研究費補助金研究成果報告書 2012

Reviews, Commentaries, etc. 【 Display / hide 】

Reviews, Commentaries, etc. 【 Display / hide 】

• 末梢神経再生へのアプローチ:効果と限界から解決すべき問題点を明らかにする　多孔性シルクフィブロイン導管の末梢神経再生効果

  松尾 知樹, 岩本 卓士, 木村 洋朗, 西島 貴之, 武谷 博明, 芝田 晋介, 中村 雅也

  末梢神経 (日本末梢神経学会)  36 ( 2 ) 203 - 203 2025.12

  ISSN  0917-6772

• 診断に難渋した手指乾癬性関節炎の2例

  高橋 翔, 清田 康弘, 鈴木 拓, 松村 昇, 岩本 卓士, 中村 雅也

  関東整形災害外科学会雑誌 (関東整形災害外科学会)  56 ( 6 ) 188 - 189 2025.12

  ISSN  0389-7087

• 「新しい試み」-次の一手　新しい知見をもとめて-　内視鏡補助下鎖骨下アプローチを用いて第1肋骨低形成を切除した胸郭出口症候群の成績

  鈴木 拓, 山口 桜, 清田 康弘, 松村 昇, 佐藤 和毅, 岩本 卓士

  日本手外科学会雑誌 ((一社)日本手外科学会)  42 ( 2 ) 90 - 90 2025.09

  ISSN  2185-4092

• トップアスリートの手指・手関節障害　次の一手　スポーツによる手指循環障害　保存療法の限界と早期復帰への工夫

  佐藤 和毅, 木之田 章, 木村 豪志, 岩本 卓士, 松村 昇, 鈴木 拓, 清田 康弘

  日本手外科学会雑誌 ((一社)日本手外科学会)  42 ( 2 ) 96 - 96 2025.09

  ISSN  2185-4092

• シルクフィブロインを用いた整形外科領域での癒着防止材の開発

  林 裕紀, 河野 友祐, 神戸 裕介, 佐々木 誠, 渕上 博貴, 亀田 恒徳, 黒岩 宇, 清田 康弘, 岩本 卓士, 藤田 順之, 中村 雅也

  日本整形外科学会雑誌 ((公社)日本整形外科学会)  99 ( 8 ) S1727 - S1727 2025.09

  ISSN  0021-5325

display all >>

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

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

• ヒトiPS細胞由来神経突起束を用いた人工神経の規格化に向けた研究

  2024.04

  -

  2027.03

  基盤研究(C), Principal investigator

• 外傷性異所性骨化の病態解明と新規治療法の探索

  2021.04

  -

  2024.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

• 手指変形性関節症に対するCT画像に基づく３Dプリンティング治療装具の開発

  2018.04

  -

  2021.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

• The establishment of computer assisted surgery for total elbow arthroplasty

  2015.04

  -

  2018.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

Courses Taught 【 Display / hide 】

Courses Taught 【 Display / hide 】

• CLINICAL CLERKSHIP IN ORTHOPAEDICS

  2025

• PATHOPHYSIOLOGICAL ISSUES IN ACUTE CARE

  2025

• LECTURE SERIES, ORTHOPAEDICS

  2025

• CLINICAL CLERKSHIP IN ORTHOPAEDICS

  2024

• PATHOPHYSIOLOGICAL ISSUES IN ACUTE CARE

  2024

display all >>

Memberships in Academic Societies 【 Display / hide 】

Memberships in Academic Societies 【 Display / hide 】

• 日本整形外科学会

  　

• 日本リウマチ学会

  　

• 日本手外科学会

  　

• 日本肘関節学会

  　

• 日本人工関節学会