第三種再生医療等における脂肪幹細胞を用いた脂肪注入

Cell-Assisted Lipotransfer Using Adipose-Derived Stem Cells under the Type 3 Regenerative Medicine Category in Japan: Institutional Procedures and Practical Application

はじめに

　脂肪由来幹細胞（adipose-derived stem cells：以下，ADSCs）を併用した脂肪注入（cell-assisted lipotransfer：以下，CAL）は，注入脂肪の生着率向上を目指した方法として，再建や美容領域において近年注目されている 1）2）。われわれは，吸引脂肪組織からADSCsを単離する前段階の，ADSCsを豊富に含む細胞分画である間質血管細胞群（stromal vascular fraction：以下，SVF）を用いた軟部組織再建治療を行っている。わが国においては，本治療は「再生医療等の安全性の確保等に関する法律（以下，再生医療等安全性確保法）」のもとで第三種再生医療等として提供される。審査を受けた提供計画に基づいてSVFの利用を行うこととなる。対外的な法的・倫理的手続きおよび院内諸手続きを適切に遂行したうえで実施する必要がある。

　本稿では，われわれの施設で本治療を実施するにあたり経験した手続きおよび実際の治療について述べる。

　Cell-assisted lipotransfer (CAL) using adipose-derived stem cells (ADSCs) has drawn increasing attention as a promising method for improving the survival rate of transplanted adipose tissue. At our institution, we perform soft-tissue reconstructions by using the stromal vascular fraction (SVF), which is a crude cell population that is rich in ADSCs isolated from aspirated fat tissue. Treatment involving CAL using the SVF is classified as Type 3 regenerative medicine under Japanʼs Act on the Safety of Regenerative Medicine. Before this treatment is initiated, a Regenerative Medicine Provision Plan must be developed and reviewed by a certified committee, followed by the planʼs submission to the regional bureau of the countryʼs Ministry of Health, Labour and Welfare. In addition, when SVF processing is conducted in an operating room (OR), the OR must be registered as a specified cell-processing facility via the submission and approval of the relevant documents. Institutional approval, including pricing as a non-insured treatment, is also required. We report our institutional protocol for CAL using the SVF including the legal, ethical, and administrative processes, the fat harvesting procedure, the SVF processing using a concentration and washing system (Kaneka Corp.), the cell evaluation method, the preparation of SVF-enriched fat, the injection techniques, and the postoperative follow-up. We also provide the details of a representative case. Although CAL may offer higher graft retention rates and greater patient satisfaction, continued scientific validation of its safety and efficacy remains essential.