一項(xiàng)新研究表明,，未受精卵子可作為干細(xì)胞的一個(gè)可靠來源，從而避免了胚胎來源的干細(xì)胞可能引起的倫理問題,。
胚胎干細(xì)胞已被證明是多種疾病的有效療法,。但一些人反對(duì)利用胚胎干細(xì)胞，因?yàn)榕咛ジ杉?xì)胞的獲得是以破壞本可以發(fā)育為人的胚胎為代價(jià),。這些倫理問題阻礙了胚胎干細(xì)胞療法的研究,，科學(xué)家因而積極尋找其它可能的干細(xì)胞來源。
為了避過使用胚胎干細(xì)胞所帶來的倫理問題,，Wake Forest大學(xué)的Kent E. Vrana博士和他的同事研究了雌猴未受精卵子衍生的干細(xì)胞,。有關(guān)研究結(jié)果發(fā)表在最新一期的《美國(guó)科學(xué)院院刊》（PNAS）的網(wǎng)絡(luò)版上。
研究人員發(fā)現(xiàn),，經(jīng)過兩年多的生長(zhǎng)和發(fā)育這些未受精卵子產(chǎn)生的干細(xì)胞的外表和活動(dòng)與胚胎衍生的干細(xì)胞一樣,。而且,，當(dāng)用適當(dāng)?shù)幕瘜W(xué)物質(zhì)處理時(shí),，這些細(xì)胞能分化為各種細(xì)胞類型，如心肌細(xì)胞和神經(jīng)細(xì)胞等,，這種多能性對(duì)于其治療價(jià)值至為重要,。
“干細(xì)胞分化為其它細(xì)胞類型的能力都是以胚胎干細(xì)胞作為參照。”文章的高級(jí)作者、密歇根州立大學(xué)的Jose B. Cibelli博士稱,。“當(dāng)然,，我們必需檢查這些未受精卵子衍生的干細(xì)胞能否治愈動(dòng)物疾病，然后才能下結(jié)論這兩種細(xì)胞類型是可互換的,。”他還指出這樣的實(shí)驗(yàn)已開始進(jìn)行,。
美國(guó)法律禁止政府資金用于胚胎干細(xì)胞研究，Cibelli 指出,。但他說,，宗教團(tuán)體可以接受使用未受精卵子作為干細(xì)胞的來源，因?yàn)槲词芫炎硬粫?huì)發(fā)育為人,。
Nonhuman primate parthenogenetic stem cells
Kent E. Vrana *, Jason D. Hipp *, Ashley M. Goss *, Brian A. McCool *, David R. Riddle , Stephen J. Walker , Peter J. Wettstein , Lorenz P. Studer ¶, Viviane Tabar ¶, Kerrianne Cunniff ||, Karen Chapman **, Lucy Vilner **, Michael D. West **, Kathleen A. Grant *, and Jose B. Cibelli ¶
*Center for Neurobehavioral Study of Alcohol, Department of Physiology and Pharmacology and Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157; Department of Microbiology and Immunology, Mayo Clinic, Rochester, MN 55905; ¶Sloan- Kettering Cancer Center, New York, NY 10021; **Advanced Cell Technology, Worcester, MA 01605; ||Millennium Pharmaceuticals, Cambridge, MA 02139; and Department of Animal Science-Physiology, Michigan State University, East Lansing, MI 48824
Parthenogenesis is the biological phenomenon by which embryonic development is initiated without male contribution. Whereas parthenogenesis is a common mode of reproduction in lower organisms, the mammalian parthenote fails to produce a successful pregnancy. We herein describe in vitro parthenogenetic development of monkey (Macaca fascicularis) eggs to the blastocyst stage, and their use to create a pluripotent line of stem cells. These monkey stem cells (Cyno-1 cells) are positive for telomerase activity and are immunoreactive for alkaline phosphatase, octamer-binding transcription factor 4 (Oct-4), stage-specific embryonic antigen 4 (SSEA-4), tumor rejection antigen 1-60 (TRA 1-60), and tumor rejection antigen 1-81 (TRA 1-81) (traditional markers of human embryonic stem cells). They have a normal chromosome karyotype (40 + 2) and can be maintained in vitro in an undifferentiated state for extended periods of time. Cyno-1 cells can be differentiated in vitro into dopaminergic and serotonergic neurons, contractile cardiomyocyte-like cells, smooth muscle, ciliated epithelia, and adipocytes. When Cyno-1 cells were injected into severe combined immunodeficient mice, teratomas with derivatives from all three embryonic germ layers were obtained. When grown on fibronectin/laminin-coated plates and in neural progenitor medium, Cyno-1 cells assume a neural precursor phenotype (immunoreactive for nestin). However, these cells remain proliferative and express no functional ion channels. When transferred to differentiation conditions, the nestin-positive precursors assume neuronal and epithelial morphologies. Over time, these cells acquire electrophysiological characteristics of functional neurons (appearance of tetrodotoxin-sensitive, voltage-dependent sodium channels). These results suggest that stem cells derived from the parthenogenetically activated nonhuman primate egg provide a potential source for autologous cell therapy in the female and bypass the need for creating a competent embryo.
Related article:Kent E. Vrana, Jason D. Hipp, Ashley M. Goss, Brian A. McCool, David R. Riddle, Stephen J. Walker, Peter J. Wettstein, Lorenz P. Studer, Viviane Tabar, Kerrianne Cunniff, Karen Chapman, Lucy Vilner, Michael D. West, Kathleen A. Grant, and Jose B. Cibelli
Nonhuman primate parthenogenetic stem cells
PNAS published September 22, 2003, 10.1073
