Many of the cells are still undifferentiated, meaning they can become any type of cell in the human body. An embryo becomes a fetus about eight weeks into gestation, when specific tissues and organs have started to form. Thousands of embryos that cannot be used for fertility treatment are discarded as medical waste each year by IVF clinics. Embryos are discarded for a variety of reasons.
Some do not develop normally, while others are found to carry genetic defects that cause serious disease. Some parents simply choose to discard leftover embryos when they are done with fertility treatment. Parents can elect to donate unused embryos to others seeking fertility treatment, a practice sometimes called embryo adoption.
But few parents choose to do so. For every embryo that is donated to others, more than embryos are discarded. Currently, more than , embryos are frozen in fertility clinics, and most will eventually be discarded. At the same time, fewer than children have been born through the Snowflakes Embryo Adoption Program since it was founded in There is no conflict between embryo adoption and stem cell research, as it is up to parents to decide whether to donate their unused embryos to others, to discard the embryos, or to donate them for medical research.
When discussing stem cells and cloning, it is important to distinguish between reproductive cloning and what scientists call therapeutic cloning. In SCNT, the nucleus of an unfertilized donor egg is extracted and replaced with the nucleus from an adult cell, such as a skin cell.
Given the proper signals, the egg can be tricked into repeatedly dividing. The resulting nuclear transfer product is allowed to develop for several days. Then some of the cells are removed and placed in a laboratory culture dish, where they grow into an embryonic stem cell line that can be used for research. In reproductive cloning, SCNT is used to create a nuclear transfer product that is then implanted into a uterus to generate a pregnancy.
These nuclear transfer products rarely develop normally and are rarely able to establish a pregnancy. Nonetheless, this is the process used to create Dolly the famous cloned sheep — after hundreds of unsuccessful attempts. A human being has never been cloned, and it is the overwhelming consensus among U. Animal-cloning experiments demonstrate that reproductive cloning is unsafe: Pregnancies are rare, and when they do occur they often produce abnormal or unhealthy offspring.
Until recently, nuclear transfer or therapeutic cloning was the only way that scientists imagined it would be possible to derive patient-specific cell lines.
But in the past year, it became possible to derive patient-specific pluripotent lines by reprogramming adult human cells, making so-called iPS cells. Given this change in the scientific landscape, and given that it has never been possible to do nuclear transfer successfully with human eggs, nobody in Michigan wants to pursue cloning. Nonetheless, iPS cells cannot replace the derivation of ES cells because iPS cells could never be used in patients due to their predisposition to cancer.
Most Americans, regardless of their religious or political affiliation, support embryonic stem cell research. A study published in Science surveyed infertility patients who had embryos stored at fertility clinics.
The study found 60 percent of the patients expressed willingness to donate embryos for stem cell research, compared to 28 percent who were willing to donate unused embryos to other patients seeking fertility treatment. We respect the values of people who hold this view. However, most Americans believe this research can be conducted ethically. Many see it as a pro-life position because this research has the potential to alleviate the suffering of thousands of people.
But most of those lines, it was later determined, do not contain viable embryonic stem cells. And all of them are contaminated with animal products. By growing embryonic stem cells that carry disease-causing genetic defects, scientists hope to learn what goes wrong inside cells — and to test new drug candidates to combat those diseases. One of the fundamental principles of clinical trials is that we test new medicines in a diverse patient population that mirrors the diversity that is present in our society.
For example, if we only test new medicines on white males, there would be a risk that we would only develop medicines that work for white males. Myth Adult stem cells are as useful as embryonic stem cells.
Fact Embryonic stem cells have the ability to create any cell type in the human body. Adult stem cells are more specialized; they generally make cells only from their tissue of origin. Thus, embryonic stem cells can do things that adult stem cells cannot do. To maximize the chances of discovering new cures, it is essential to pursue research on both embryonic and adult stem cells. In addition, the technique can cause mutations that predispose cells to cancer.
As a result, some scientists are concerned that the reprogrammed cells will never be suitable for use in patients. For the foreseeable future, stem cell researchers agree that research should continue along all avenues, using embryonic stem cells, adult stem cells, and reprogrammed cells. Myth Adult stem cells have been proven effective in treating more than 70 diseases. Fact While adult stem cell research holds much promise, blood stem cells offer the only proven adult stem cells therapies.
The claim that adult stem cells have been used to cure more than 70 diseases has been widely discredited. Myth Stem cells from amniotic fluid and umbilical cord blood can be used instead of embryonic stem cells. Fact Amniotic fluid and umbilical cord blood contain adult stem cells. They hold promise for therapy but do not have the properties or potential of embryonic stem cells. Stem cell research is one of the most fascinating areas of contemporary biology, but, as with many expanding fields of scientific inquiry, research on stem cells raises scientific questions as rapidly as it generates new discoveries.
Some stem cells, such as the adult bone marrow or peripheral blood stem cells, have been used in clinical therapies for over 40 years. Other therapies utilizing stem cells include skin replacement from adult stem cells harvested from hair follicles that have been grown in culture to produce skin grafts.
There were side effects accompanying these studies and further investigation is warranted. Although there is much research to be conducted in the future, these studies give us hope for the future of therapeutics with stem cell research.
Bone marrow and peripheral blood stem cell transplants have been utilized for over 40 years as therapy for blood disorders such as leukemia and lymphoma, amongst many others. Scientists have also shown that stem cells reside in most tissues of the body and research continues to learn how to identify, extract, and proliferate these cells for further use in therapy.
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National Institutes of Health. Accessed July 23, Stem cell basics. Nelson TJ, et al. Stem cell therapy and congenital heart disease. Journal of Cardiovascular Development and Disease. Terashvili M, et al. Stem cell therapies in cardiovascular disease. Journal of Cardiothoracic and Vascular Anesthesia. In press. Samsonraj RM, et al. Concise review: Multifaceted characterization of human mesenchymal stem cells for use in regenerative medicine.
Stem Cells Translational Medicine. Blood-forming stem cell transplants. National Cancer Institute. Abbaspanah B, et al. Advances in perinatal stem cells research: A precious cell source for clinical applications.
Routine tests during pregnancy. The American College of Obstetricians and Gynecologists. Stem cell facts.
International Society for Stem Cell Research. Matoba S, et al. Somatic cell nuclear transfer reprogramming: Mechanisms and applications. Cell Stem Cell ; National Institutes of Health guidelines for human stem cell research. See also Acute lymphocytic leukemia Acute myelogenous leukemia Adjuvant therapy for cancer Alternative cancer treatments: 10 options to consider Amyloidosis Anemia Aplastic anemia Atypical cells: Are they cancer? Advice for dealing with what comes next Cancer-related fatigue Cancer pain: Relief is possible Cancer risk: What the numbers mean Cancer surgery Cancer survival rate Cancer survivors: Care for your body after treatment Cancer survivors: Late effects of cancer treatment Cancer survivors: Managing your emotions after cancer treatment Cancer survivors: Reconnecting with loved ones after treatment Cancer treatment decisions: 5 steps to help you decide Cancer treatment for men: Possible sexual side effects Cancer treatment for women: Possible sexual side effects Cancer treatment myths Cancer Vaccine Research Chemotherapy side effects: A cause of heart disease?
Chronic lymphocytic leukemia Chronic myelogenous leukemia Cord blood banking Curcumin: Can it slow cancer growth? Cancer-related diarrhea DiGeorge syndrome 22q High-dose vitamin C: Can it kill cancer cells?
Hodgkin's lymphoma Hodgkin's disease Hodgkin's vs. Type 1 diabetes Stem cell transplant How cancer spreads PICC line placement When cancer returns: How to cope with cancer recurrence Your secret weapon during cancer treatment?
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