Stem Cell Research
Moorefield et al. demonstrated the potential for amniotic fluid stem cells to modulate immune response and to be used as immunotherapy.
In 2012, Prasongchean et al. demonstrated the use of amniotic-fluid stem cells in tissue repair. However, stem cells may not fully differentiate into desired cell types and may not completely integrate into the target tissue. When amniotic-fluid stem cells were injected into the spinal cord of injured chick embryos, the cells never did fully differentiate into targeted neurons; however, there was decreased injury and increased survival rate.
Lai et al. conducted a study using amniotic-fluid cells to restore ovarian function in mice. The researchers proposed that their techniques could help treat women experiencing premature ovarian failure improve or restore reproductive health.
Amniotic-fluid stem cells have also been used to restore intestinal function and structure in rodents. The research was conducted to discover new ways to treat necrotizing colitis in infants. Necrotizing colitis is the most common gastrointestinal emergency in newborns and carries a 15% to 30% mortality rate. Currently, the only treatment for necrotizing colitis is surgery and the long-term effects can be devastating. More research is required, but the success of the treatment in rodents gives hope for eventual treatment in humans using amniotic-fluid stem cells to effectively treat this disorder.
Jeannie Randall
Aspen University
See Also: Cartilage, Tendons, and Ligaments: Current Research on Isolation or Production of Therapeutic Cells; Mesenchymal Stem Cells; Spinal Cord Injury; Stem Cell Banking.
Further Readings
Advanced Cell Technology. “Ethical Stem Cell Work Advances.” (2014). http://www.advancedcell.com/news-and-media/act-in-the-news/ethical-stem-cell-work-advances/ (Accessed March 2014).
American Center for Law and Justice. “Stem Cell Research.” http://aclj.org/pro-life-2/stem-cell-research (Accessed April 2014).
Anker, P. S. In’t, S. A. Scherjon, C. Kleijburg-Van Der Keur, et al. “Isolation of Mesenchymal Stem Cells of Fetal or Maternal Origin From Human Placenta.” Stem Cells, v.22/7 (2004).
Govtrack.US. https://www.govtrack.us/congress/bills/110/hr1892 (Accessed March 2014).
Lai, D., F. Wang, Y. Chen, et al. “Human Amniotic Fluid Stem Cells Have a Potential to Recover Ovarian Function in Mice With Chemotherapy-Induced Sterility.” BMC Developmental Biology, v.13/34 (2013).
Mosquera, A., J. L. Fernandez, A. Campos, et al. “Simultaneous Decrease of Telomere Length and Telomerase Activity With Ageing of Human Amniotic Fluid Cells.” Journal of Medical Genetics, v.36 (1999).
National Council of State Legislatures. (2008). http://www.ncsl.org/research/health/embryonic-and-fetal-research-laws.aspx (Accessed April 2014).
PLOS.org. “Cloned, CD117 Selected Human Amniotic Fluid Stem Cells Are Capable of Modulating the Immune Response.” http://www.plosone.org/article/metrics/info:doi/10.1371/journal.pone.0026535#citedHeader (Accessed April 2014).
Prasongchean, W., M. Bagni, C. Calzarossa, et al. “Amniotic Fluid Stem Cells Increase Embryo Survival Following Injury.” Stem Cells and Development, v.21/5 (2012).
Torricelli, F., L. Brizzi, P. A. Bernabei, et al. “Identification of Hematopoietic Progenitor Cells in Human Amniotic Fluid Before the 12th Week of Gestation.” Italian Journal of Anatomic Embryology, v.98 (1993).
U.S. National Library of Medicine. “Amniocentesis.” http://www.nlm.nih.gov/medlineplus/ency/article/003921.htm (Accessed March 2014).
Zani, Augusto, Mara Cananzi, Francesco Fascetti-Leon, et al. “Amniotic Fluid Stem Cells Improve Survival and Enhance Repair of Damaged Intestine in Necrotising Enterocolitis via a COX-2 Dependent Mechanism.” Gut, v.63/2 (2013).
Animal Cloning
Animal Cloning
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Animal Cloning
In biology, the term cloning refers to the process of producing genetically identical individuals. Cloning is the practice of separating a group of cells or cell derivates so that each produces only an identical copy of its type. This process occurs naturally in organisms that reproduce asexually, such as plants, insects, and bacteria. The practice of cloning has long historical roots, as it has been a common part of the human experience for thousands of years; for example, growing a plant from a cutting is an early type of cloning. The more recent history of experimental cloning of animals that do not normally reproduce asexually dates back to the early 1900s, when scientist Hans Spemann split an early salamander embryo into two parts, which then developed into two full and distinct organisms. This proved that embryonic cells carry all the genetic information required to develop into a new organism. However, cloning of advanced animals had not been considered possible until the successful cloning of the first mammal, a sheep called Dolly, in 1997. The cloning of Dolly was a momentous scientific and technological development; it also opened the door to the possibility of human cloning, and with it, myriad related medical issues and ethical concerns. Many other mammals, from rodents to cows, have since been successfully cloned.
During the 1970s, cells of two separate embryos of different strains of mice were joined at an early stage of development, in order to produce a single chimeric embryo that later developed into adult mice, which exhibited characteristics of both strains. Progress in the experimental manipulation of mammalian embryos has led to the development of cutting-edge techniques for the production of genetically modified animals. Injection of cloned DNA into the pronuclei of fertilized one-cell eggs allows the production of a transgenic animal with a foreign gene that has been deliberately inserted into its genome. The foreign gene is generally constructed using recombinant DNA technologies. In addition to a structural gene that will code for an RNA or protein product, the recombinant DNA usually includes other sequences in order to be expressed correctly in the host cells. Other important techniques were developed later, such as retrovirus-mediated transgenesis and embryonic stem cell–mediated gene transfer, which is based on the creation of chimeric embryos.
The technology to produce transgenic and cloned animals often have overlapping goals but they produce different types of animals. Transgenic commonly refers to an animal or plant that contains one or more genes from another organism, incorporated into its own genome. It is capable of passing on the foreign genes to its offspring. A cloned animal, however, is an organism that is genetically identical to its progenitor. Cloning remains a topic of deeply complex scientific and ethical issues. The potential for cloning to cure disease, to increase and better the food supply worldwide, and to save and recover endangered species
