一項新研究表明，未受精卵子可作為干細胞的一個可靠來源,，從而避免了胚胎來源的干細胞可能引起的倫理問題,。
胚胎干細胞已被證明是多種疾病的有效療法。但一些人反對利用胚胎干細胞,，因為胚胎干細胞的獲得是以破壞本可以發(fā)育為人的胚胎為代價,。這些倫理問題阻礙了胚胎干細胞療法的研究，科學家因而積極尋找其它可能的干細胞來源,。
為了避過使用胚胎干細胞所帶來的倫理問題,，Wake Forest大學的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胞。有關研究結果發(fā)表在最新一期的《美國科學院院刊》（PNAS）的網(wǎng)絡版上,。
研究人員發(fā)現(xiàn),，經(jīng)過兩年多的生長和發(fā)育這些未受精卵子產生的干細胞的外表和活動與胚胎衍生的干細胞一樣。而且,，當用適當?shù)幕瘜W物質處理時,，這些細胞能分化為各種細胞類型，如心肌細胞和神經(jīng)細胞等,，這種多能性對于其治療價值至為重要,。
“干細胞分化為其它細胞類型的能力都是以胚胎干細胞作為參照。”文章的高級作者,、密歇根州立大學的Jose B. Cibelli博士稱,。“當然，我們必需檢查這些未受精卵子衍生的干細胞能否治愈動物疾病,，然后才能下結論這兩種細胞類型是可互換的,。”他還指出這樣的實驗已開始進行。
美國法律禁止政府資金用于胚胎干細胞研究,，Cibelli 指出,。但他說，宗教團體可以接受使用未受精卵子作為干細胞的來源,，因為未受精卵子不會發(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
