Fertility preservation by oogonial stem cells in cryopreserved ovarian tissue

2018 Fiscal Year Final Research Report

• Project/Area Number: 26462499
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Obstetrics and gynecology
• Research Institution: Saitama Medical University
• Principal Investigator: Takai Yasushi 埼玉医科大学, 医学部, 教授 (60323549)
• Research Collaborator: SEKI hiroyuki ; ISHIHARA osamu
• Project Period (FY): 2014-04-01 – 2019-03-31
• Keywords: 卵子幹細胞 / 卵巣凍結 / 妊孕性温存

Outline of Final Research Achievements

In order to utilize oogonial stem cells (OSCs) extracted from ovarian tissue, the following research achievements were obtained.
MAEL and TEX11, two key meiosis-related proteins, were identified during the human fetal oogenesis in 8-19 weeks of gestation. These findings were confirmed using in vitro differentiation of OSCs into in vitro derived oocytes and of ESCs into primordial germ cell-like cells and oocyte-like cells, as models.
Culture of mouse OSCs on a collagen-based extracellular matrix (ECM) significantly elevated the rate of differentiation of the cells into in vitro derived (IVD) oocytes. On the other hand, human OSCs exhibited increased differentiation into IVD oocytes when cultured on laminin. These data, along with in silico analysis of ECM protein profiles in human fetal ovaries, indicate that ovarian ECM-based niche components function in a species-specific manner to control OSC differentiation.

Free Research Field

生殖内分泌学

Academic Significance and Societal Importance of the Research Achievements

ヒト卵巣組織の凍結保存は、悪性腫瘍に対する化学療法や放射線療法によって卵巣機能が損なわれる可能性がある若年がん女性の生殖機能を温存するために不可欠な技術である。しかし、妊娠するためには再移植が必要であり、移植組織からの悪性腫瘍の再発の可能性があることが問題であった。これを克服することを目的として、我々がヒト卵巣組織から抽出した卵子幹細胞（OSCs）の体外培養によって卵細胞を得るための基礎的研究を施行した。
従来、OSCｓなどの生殖幹細胞から卵細胞を分化させるためには胎児期の卵巣組織が別途必要であったが、本研究の成果はOSCsを用いた「人工卵巣」構築への重要な足がかりとなるものである。