Stem cell

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Stem cells are primal undifferentiated cells which retain the ability to differentiate into other cell types. This ability allows them to act as a repair system for the body, replenishing other cells as long as the organism is alive.

Medical researchers believe stem cell research, in the field of regenerative medicine, has the potential to change the face of human disease by being used to repair specific tissues or to grow organs. Still, as government reports point out, "significant technical hurdles remain that will only be overcome through years of intensive research."[1]

The study of stem cells is attributed as beginning in the 1960s after research by Canadian scientists Ernest A. McCulloch and James E. Till.

Contents

Types

Stem cells are categorized by potency which describes the specificity of that cell.

  • Totipotent stem cells are produced from the fusion of an egg and sperm cell. Cells produced by the first few divisions of the fertilized egg cell are also totipotent. These cells can grow into any type of cell without exception.
  • Pluripotent stem cells are the descendants of totipotent cells and can grow into any cell type except for totipotent stem cells.
  • Multipotent stem cells can produce only cells of a closely related family of cells (e.g. blood cells such as red blood cells, white blood cells and platelets).
  • Progenitor (sometimes called unipotent) cells can produce only one cell type; but, have the property of self-renewal which distinguishes them from non-stem cells.

Stem cells are also categorized according to their source, as either adult or embryonic.

Adult stem cells are undifferentiated cells found among differentiated cells of a specific tissue and are mostly multipotent cells. They are already being used in treatments for over one hundred diseases and conditions. They are more accurately called somatic (Greek σωμα sōma = body) stem cells, because they need not come from adults but can also come from children or umbilical cords. Particularly interesting are adult stem cells termed "spore-like cells". They are present in all tissues (Vacanti, M. P., A. Roy, J. Cortiella, L. Bonassar, and C. A. Vacanti. 2001. Identification and initial characterization of spore-like cells in adult mammals. J Cell Biochem 80:455-60.)and seem to survive long time periods and harsh conditions.
Embryonic stem cells are cultured cells obtained from the undifferentiated inner mass cells of a blastocyst, an early stage embryo that is 50 to 150 cells. Embryonic stem cell research is "thought to have much greater developmental potential than adult stem cells," according to the National Institutes of Health.[2] However, embryonic stem cell research is still in the basic research phase, as these stem cells were first isolated in 1998 (at least for humans), whereas adult stem cells have been studied since the 1960s.[3] Research with embryonic stem cells derived from humans is controversial because, in order to start a stem cell 'line' or lineage, it requires the destruction of a blastocyst, which some people believe to be a human being. (See below: embryonic stem cell ethical debate)

Sources of stem cells

Cord blood stem cells

Blood from the placenta and umbilical cord that are left over after birth is one source of adult stem cells. Since 1988 these cord blood stem cells have been used to treat Gunther's disease, Hunter syndrome, Hurler syndrome, Acute lymphocytic leukemia and many more problems occurring mostly in children. It is collected by removing the umbilical cord, cleansing it and withdrawing blood from the umbilical vein. This blood is then immediately analyzed for infectious agents and the tissue-type is determined. The cord blood is processed and depleted of red blood cells before being stored in liquid nitrogen for later use, at which point it is thawed, washed of the cryoprotectant, and injected through a vein of the patient. This kind of treatment, where the stem cells are collected from another donor, is called allogeneic treatment. When the cells are collected from the same patient on whom they will be used, it is called autologous and when collected from identical individuals, it is referred to as syngeneic. Xenogeneic transfer of cells (between different species) is very underdeveloped and is said to have little research potential.

Researchers in South Korea announced in November 2004 that they had successfully used multipotent cord blood (adult) stem cell treatments to enable a paralyzed woman to walk with the aid of a walker. This was achieved by isolating the stem cells from the umbilical cord blood and injecting the cells into the damaged part of the woman's spinal cord. Work was done by Chosun University professor Song Chang-hun, Seoul National University professor Kang Kyung-susn, and the Seoul Cord Blood Bank.[4] [5] [6] [7] While exciting, many more studies are required to establish that such treatments are effective.

Adult stem cells

Stem cells can be found in all adult and young adult beings. Adult stem cells are undifferentiated cells that reproduce daily to provide certain specialized cells—for example 200 billion red blood cells are created each day in the body from hemopoietic stem cells. Until recently it was thought that each of these cells could produce just one particular type of cell—this is called differentiation (see Morphogenesis). However in the past few years, evidence has been gathered of stem cells that can transform into several different forms. Bone marrow stromal stem cells are thought to be able to transform into liver, nerve, muscle, hair follicle and kidney cells. Although there is some evidence that this type of transdifferentiation can occur, many scientists are skeptical of these claims and we are still learning about such transdifferentiated cells.

Adult stem cells may be even more versatile than this. Researchers at the New York University School of Medicine have extracted stem cells from the bone-marrow of mice which they say are pluripotent. Turning one type of stem cell into another is called transdifferentiation.

In fact, useful sources of adult stem cells are being found in organs all over the body. Researchers at McGill University in Montreal have extracted stem cells from skin that are able to differentiate into many types of tissue, including neurons, smooth muscle cells and fat-cells. These were found in the dermis, the inner layer of the skin. These stem cells play a pivotal role in healing small cuts. Blood vessels, the dental pulp, the digestive epithelium, the retina, liver and even the brain are all said to contain stem cells.

The Tulane University Center for Gene Therapy is the first U.S. government-funded center to produce and distribute well-characterized adult stem cells to researchers around the globe. These standardized cells are critical to ensuring comparability and reproducibility of world-wide research.

Adipose derived adult stem (ADAS) cells have also been isolated from fat, e.g. from liposuction. This source of cells seems to be similar in many ways to Mesenchymal stem cells (MSCs) derived from bone marrow, except that it is possible to isolate many more cells from fat. These cells have been shown to differentiate into bone, fat, muscle, cartilage, and neurons. These cells have been recently used to successfully repair a large cranial defect in a human patient [8].

Olfactory adult stem cells have been successfully grown by Prof. Alan Mackay-Sim,[9] deputy director of Griffith University’s new Institute for Cellular and Molecular Therapies in Brisbane, Queensland, Australia. He was awarded Queenslander of the Year in 2003 for his work. His team successfully grew adult stem cells harvested from the human nose, and was published in the journal Developmental Dynamics. The Courier-Mail cited him as follows (22 March 2005, p. 4):

Adult stem cells isolated from the olfactory mucosa (cells lining the inside of the nose involved in the sense of smell) have the ability to develop into many different cell types if they are given the right chemical environment.
These adult olfactory stem cells appear to have the same ability as embryonic stem cells in giving rise to many different cell types but have the advantage that they can be obtained from all individuals, even older people who might be most in need to stem cell therapies. ...
Adult olfactory stem cells are readily obtained from the nose and relatively easy to grow and multiply in the lab. In a few weeks we can make plenty of cells for transplantation.


An advantage of adult stem cells is that, since they can be harvested from the patient, potential ethical issues and immunogenic rejection are averted. Although many different kinds of multipotent stem cells have been identified, adult stem cells that could give rise to all cell and tissue types have not yet been found. Adult stem cells are often present in only minute quantities and can therefore be difficult to isolate and purify. There is also limited evidence that they may not have the same capacity to multiply as embryonic stem cells do. Finally, adult stem cells may contain more DNA abnormalities—caused by sunlight, toxins, and errors in making more DNA copies during the course of a lifetime. However, there are a number of clinically proven adult stem cell successes.

Adult stem cells do appear in "minute quantities" however, these minute in-vivo quantities can be multiplied in-vitro to therapeutic numbers. For example, many patients have received treatment for heart disease using adult stem cells originating in bone marrow. In 2005, technology has become available[10] whereby stem cells can be harvested, differentiated and multiplied from about ½ pint of one’s own blood.”

Several types of heart diseases have been treated in clinical trials and also is available commercially. Patients such as Jeannine Lewis[11], have traveled to Thailand to receive stem cell therapy for their heart disease. Dr. Amit Patel of the University of Pittsburgh McGowen Institute for Regenerative Medicine[12] has been one of the leaders in stem cell therapy for heart disease.

Spore-Like Cells

Spore-like cells were described first by Vacanti et al. in 2001 (Vacanti, M. P., A. Roy, J. Cortiella, L. Bonassar, and C. A. Vacanti. 2001. Identification and initial characterization of spore-like cells in adult mammals. J Cell Biochem 80:455-60.)They are extremely small (i.e. <5 micrometer). They appear to lie dormant and to be dispersed throughout the parenchyma of virtually every tissue in the body. Being dormant, they survive in extremely low oxygen environments and other hostile conditions, known to be detrimental to mammalian cells, including extremes of temperatures. Spore-like cells remain viable in unprepaired tissue, frozen at -86°C (using no special preservation techniques) and then thawed, or heated to 85°C for more than 30 min. This has led researchers to try to revitalize spore-like cells from tissue samples of frozen carcasses deposited in permafrost for decades (frozen walrus meat >100 years old)(mammuth and bison, Alaska 50,000 years old). In vitro, these structures have the capacity to enlarge, develop, and differentiate into cell types expressing characteristics appropriate to the tissue environment from which they were initially isolated. Vacanti et al.believe that these unique cells lie dormant until activated by injury or disease, and that they have the potential to regenerate tissues lost to disease or damage. Because the cell-size of less than 5 micrometers seems rather small as to contain the entire human germ-line genome the authors speculate on the "concept of a minimal genome" for these cells.

Embryonic stem cells

Embryonic stem cells are stem cells derived from the undifferentiated inner mass cells of a blastocyst, an early stage embryo consisting of 50-150 cells. They are pluripotent, meaning they are able to grow into each of the more than 200 cell types in the body as long as they are specified to do so. Embryonic stem cells can be obtained from a cloned blastocyst, created by fusing a denucleated egg cell with a patient's cell. The blastocyst produced is allowed to grow to the size of a few tens of cells, and stem cells are then extracted. Because they are obtained from a clone, they are genetically compatible with the patient. More commonly, they are obtained for research purposes from uncloned blastocysts, such as those discarded from in vitro fertilization clinics. Such cells might be rejected if transplanted into a patient. A possible solution for this is to derive multiple well-characterized embryonic stem cell lines from different genetic and ethnic backgrounds; treatment can then be tailored to the patient, minimizing the risk of rejection.

The breakthrough in embryonic stem cell research came in November 1998 when a group led by James Thomson at the University of Wisconsin-Madison first developed a technique to isolate and grow the cells. Embryonic stem cell researchers are currently attempting to grow the cells beyond the first stages of cell development, to overcome difficulties in host rejection of implanted stem cells, and to control the multiplying of implanted embryonic stem cells, which otherwise multiply uncontrollably, producing a tumor. A major development in research came in May 2003, when researchers announced that they had successfully used embryonic stem cells to produce human egg cells. These egg cells could potentially be used in turn to produce new stem cells. If research and testing proves that artificially created egg cells could be a viable source for embryonic stem cells, they noted, then this would remove the necessity of starting a new embryonic stem cell line with the destruction of a blastocyst. Thus, the controversy over donating human egg cells and blastocysts could potentially be resolved, though a blastocyst would still be required to start each cycle.

The online edition of Nature Medicine published a study on January 23, 2005 which stated that the human embryonic stem cells available for federally funded research are contaminated with nonhuman molecules from the culture medium used to grow the cells, for example, mouse cells and other animal cells. The nonhuman cell-surface sialic acid can compromise the potential uses of the embryonic stem cells in humans--according to scientists at the University of California, San Diego[13].

A study was published in the online edition of Lancet Medical Journal on March 8, 2005 that detailed information about a new stem-cell line which was derived from human embryos under completely cell- and serum-free conditions. This event is significant because exposure of existing human embryonic stem-cell lines to live animal cells and serum risks contamination with pathogens that could lead to human health risks. After more than 6 months of undifferentiated proliferation, these cells retained the potential to form derivatives of all three embryonic germ layers both in vitro and in teratomas. These properties were also successfully maintained (for more than 30 passages) with the established stem-cell lines. (Lancet Medical Journal)

Treatments

Current treatments

For over 30 years, bone marrow (adult) stem cells have been used to treat cancer patients with conditions such as leukemia and lymphoma. During chemotherapy, most growing cells are killed by the cytotoxic agents. These agents not only kill the leukemia or neoplastic cells, but also the, which release the stem cells from the bone-marrow. These are removed before chemotherapy, which kills most of them, and are re-injected afterwards.

Potential treatments

Cancer

Research injecting neural (adult) stem cells into the brains of rats can be very successful in treating cancerous tumors. With traditional techniques brain cancer is almost impossible to treat because it spreads so rapidly. Researchers at the Harvard Medical School injected adult stem cells genetically engineered to convert a separately injected non-toxic substance into a cancer-killing agent. Within days the adult stem cells had migrated into the cancerous area and the injected substance was able to reduce tumor mass by 80 percent.

Spinal cord injury

According to the October 7, 2005 issue of The Week, University of California researchers injected stem cells from aborted human fetuses into paralyzed mice, which resulted in the mice regaining the ability to move and walk four months later. The researchers discovered upon dissecting the mice that the stem cells regenerated not only the neurons, but also the cells of the myelin sheath, a layer of cells with which nerve fibers communicate with the brain (damage to which is often the cause of neurological injury in humans). [14]

Stem cell injection restores ability to walk

A team of Korean researchers reported on November 25, 2004, that they had transplanted multipotent adult stem cells from umbilical cord blood to a patient suffering from a spinal cord injury and she can now walk on her own, with difficulty. The patient had not even been able stand up for the last 19 years. The team was co-headed by researchers at Chosun University, Seoul National University and the Seoul Cord Blood Bank (SCB). For the unprecedented clinical test, the scientists isolated adult stem cells from umbilical cord blood and then injected them into the damaged part of the spinal cord.

Using stem cells, the tests were able to avoid triggering a negative bodily reaction, which are common in other transplantations, according to Hoon Han, one of the researchers. "We don’t need a strict match between cord blood stem cell type and the immune system of a patient because the latter accepts the former pretty well thanks to its immaturity," Han said. [15] [16] [17] [18] The Korean researchers have followed up on their original work. The original treatment was conducted in November 2004. On April 18, 2005, the researchers announced that they will be conducting a second treatment on the woman. [19] The researchers have followed up with a case study write-up on their work. It is located in the journal Cytotherapy. [20]

Blastocyst stem cells switched to neurons

In January 2005, researchers at the University of Wisconsin-Madison differentiated human blastocyst stem cells into neural stem cells, then into the beginnings of motor neurons, and finally into spinal motor neuron cells, the cell type that, in the human body, transmits messages from the brain to the spinal cord. The newly generated motor neurons exhibited electrical activity, the signature action of neurons. Lead researcher Su-Chun Zhang described the process as "you need to teach the blastocyst stem cells to change step by step, where each step has different conditions and a strict window of time."

Transforming blastocyst stem cells into motor neurons had eluded researchers for decades. The next step will be to test if the newly generated neurons can communicate with other cells when transplanted into a living animal; the first test will be in chicken embryos. Su-Chun said their trial-and-error study helped them learn how motor neuron cells, which are key to the nervous system, develop in the first place.

The new cells could be used to treat diseases like Lou Gehrig's disease, muscular dystrophy, and spinal cord injuries.

Muscle damage

Adult stem cells are also apparently able to repair muscle damaged after heart attacks. Heart attacks are due to the coronary artery being blocked, starving tissue of oxygen and nutrients. Days after the attack is over, the cells try to remodel themselves in order to become able to pump harder. However, because of the decreased blood flow this attempt is futile and results in even more muscle cells weakening and dying. Researchers at Columbia-Presbyterian found that injecting bone-marrow stem cells, a form of adult stem cells, into mice which had had heart attacks induced resulted in an improvement of 33 percent in the functioning of the heart. The damaged tissue had regrown by 68 percent.

Heart damage

Using the patient's own bone marrow derived stem cells, Dr. Amit Patel at the University of Pittsburgh, McGowan Institute of Regenerative Medicine has shown a dramatic increase in ejection fraction for patients with congestive heart failure. Working with critically ill heart patients, researchers in Vienna have successfully used Mesenchymal stem cells to regenerate healthy new heart tissue. The adult stem cells were harvested from the patient's own bone marrow and injected into the ventricle. The heart is stopped for approximately two minutes to allow the adult stem cells to attach to the existing heart tissue. The patient is only under local anesthesia so that the surgeons can monitor how the lack of cerebral oxygen is affecting the patient. The heart is then restarted and incisions closed. The procedure is minimally invasive, as far as heart surgeries are concerned.

All of the patients that received the new treatment experienced repaired scar tissue and most had nearly complete return of proper heart function.

Low blood supply

In December 2004, a team of researchers led by Dr. Luc Douay at the University of Paris developed a method to produce large numbers of red blood cells. The Nature Biotechnology paper, entitled Ex vivo generation of fully mature human red blood cells, describes the process: precursor red blood cells, called hematopoietic stem cells, are grown together with stromal cells, creating an environment that mimics the conditions of bone marrow, the natural site of red blood cell growth. Erythropoietin, a growth factor, is added, coaxing the stem cells to complete terminal differentiation into red blood cells.

Further research into this technique will have potential benefits to gene therapy, blood transfusion, and topical medicine.

Baldness

Hair follicles also contain stem cells, and some researchers predict research on these follicle stem cells may lead to successes in treating baldness through "hair multiplication," also known as "hair cloning," as early as 2007. This treatment is expected to work through taking stem cells from existing follicles, multiplying them in cultures, and implanting the new follicles into the scalp. Later treatments may be able to simply signal follicle stem cells to give off chemical signals to nearby follicle cells which have shrunk during the aging process, which in turn respond to these signals by regenerating and once again making healthy hair. Hair Cloning Nears Reality as Baldness Cure (WebMD Nov. 2004)

Missing teeth

In 2004, scientists at King's College discovered a way to cultivate a complete tooth in mice [21] and were able to grow them stand-alone in the laboratory. Researchers are confident that this technology can be used to grow live teeth in human patients.

In theory, a small ball of adult stem cells implanted in the gums will give rise to the tooth, which is expected to take two months to grow. It will fuse with the jawbone and release chemicals that encourage nerves and blood vessels to connect with it. The process is similar to what happens when humans grow their original adult teeth.

Its estimated that it may take until 2009 before the technology is widely available to the general public, but the genetic research scientist behind the technique, Professor Paul Sharpe of King's College, estimates the method could be ready to test on patients by 2007 [22]. His startup company, Odontis, fully expects to offer tooth replacement therapy by the end of the decade.

Blindness

Since 2003, researchers have successfully transplanted corneal and limbal stem cells into damaged eyes to restore vision. Using cultured stems cells from aborted fetuses, scientists are able to grow a thin sheet of totipotent stem cells in the laboratory. When these sheets are transplanted over the eye, the stem cells stimulate renewed repair, eventually restoring vision [23].

The latest development was in June of 2005, when researchers at the Queen Victoria Hospital of Sussex, England were able to restore the sight of forty patients using the same technique. The group, led by Dr. Sheraz Daya, was able to successfully use adult stem cells obtained from the patient, a relative, or even a cadaver. Further rounds of trials are ongoing [24].

As more research yields increasingly precise techniques, stem cell transplantation to restore vision may become viable on a large scale. However, the success rate of the procedure is still low, from 20 to 70 percent [25], and further clinical research is intensely required before any credible claim can be made.

Embryonic stem cell ethical debate

The controversy over stem cell research arises from how they are created. Some are the by-product of in-vitro fertilization attempts by couples trying to have children. Unused ones, rather than being discarded, are harvested. Others are deliberately created specifically for this research.

Blastocysts

A human blastocyst
Enlarge
A human blastocyst

A blastocyst is a stage of development of an embryo when it is around six days old and made up of about 120 cells. A blastocyst at the stage at which embryonic stem cells would be extracted is still young enough to be able to divide into two embryos, making identical twins, or in rare cases, merge with another blastocyst, even one of the opposite sex[1], to create a chimera, an individual comprised of populations of cells with two different sets of DNA. From the biological point of view, these points mean the blastocyst is not yet an individual. Blastocysts are an early developmental stage far from possessing a nervous system (or any other organs), and thus biologically speaking do not have feelings.

This view raises other issues, as the blastocysts involved in the research are left over from in vitro fertility therapy, and when not used in additional therapy or in embryonic stem cell research are destroyed or frozen indefinitely by the thousands[26]. To some, this does not address the concern that using doomed blastocysts in embryonic stem cell research is viewed as instrumentalizing a developing human being.

In the U.S., the leaders of many Christian groups (such as Catholics, Eastern Orthodox and Fundamentalists) as well as other unaffiliated and non-religious groups, believe that a human blastocyst is a human being, with the according human rights, and therefore oppose embryonic stem cell research because the start of each cell line involves the destruction of a blastocyst. Catholics view embryonic stem cell research - not adult stem cell research though - as intrinsically evil and never to be supported since it requires the death of an innocent human life created by God.

Others do not view a blastocyst as a human being, and may instead see opposition of stem cell research as unfounded due to the suffering that new medical technologies could prevent. Many Jews, Muslims, Humanists, Mormons, and Unitarian Universalists, liberal members of the Church of Christ, as well as a significant number of mainstream Christians are supportive of embryonic stem cell research.

Another area in embryonic stem cells that can be of ethical concern is the use of therapeutic cloning. This involves using a blastocyst cloned from the patient so that the resulting stem cells are a genetic match. Some see this as being in a category of unnaturalness shared with reproductive human cloning, in which cloned blastocysts would be allowed to grow into embryos and eventually infants. [27]

Policy debate in the U.S.

Origins of debate

In 1995, Congress passed the Dickey Amendment, prohibiting federal funding of research that involves the use of a human embryo. Privately funded research led to the breakthrough that made embryonic stem cell research possible in 1998, prompting the Clinton Administration to develop federal regulations for its funding. Preparations for this funding were completed in 2001. President George W. Bush announced, on August 11, 2001 that federal funds could be used to support research on the newly developed field of human embryonic stem cells, but that funding would be limited to "existing (embryonic) stem cell lines where the 'life-and-death decision' has already been made" [28]. This limitation does not apply to research involving stem cells from other sources, such as umbilical cord blood, placentas, and adult and animal tissues. Some conservative religious groups felt the restrictions should have been stronger, while some scientists felt frustrated with the restrictions.

In 2002, President Bush appointed the Council on Bioethics, an advisory group composed of 18 doctors, legal and ethical scholars, scientists and a journalist [29]. In February 2004, Bush removed from the council two advocates of embryonic stem cell research, professor of ethics William May and biologist Elizabeth Blackburn [30]. In their place, he appointed pediatric neurosurgeon Dr. Benjamin Carson, political scientist Dr. Diana Schaub, and professor of government Dr. Peter Lawler, all of whom have a more cautious point of view toward embryonic stem cell research. All of the Council members support adult stem cell research. Some scientists are concerned that embryonic stem cell research has become a politicized issue instead of a scientific issue in the national mindset, and feel that the politicization distorts representation of the scientific issues.

Private funding

The Bush administration's decision does not prohibit private embryonic stem cell research. Pharmaceutical companies and biotechnology companies initially expressed little interest because they consider therapies based on cells, which might have to be tailored to each patient, to be less profitable than one-size-fits-all drugs. However, there are start-up biotechs entering the field. They include StemCells Inc. and Aastrom Biosciences. Others are reluctant to enter the market because they fear government restrictions preventing them from capitalizing on the research. However, private research groups (such as pharmaceutical and biotechnology companies) are now financing individual medical treatments, including all of those mentioned in this article.

Congressional response

In April 2004, 206 members of Congress, including many moderate Republicans, signed a letter urging President Bush to expand federal funding of embryonic stem cell research beyond what Bush had already supported.

In May 2005, the House of Representatives voted 238-194 to loosen the limitations on embryonic stem-cell research — by allowing surplus frozen embryos from in vitro fertilization clinics to be used for stem cell research with the permission of donors — despite Bush's promise to veto the bill if passed. [31] Similar measures are pending in the Senate. On July 29, 2005, Senate Majority Leader William H. Frist (R-TN), announced that he too favored loosening restrictions on federal funding of embryonic stem-cell research, making passage of an embryonic stem-cell funding bill in the Senate more likely. [32]

Polls regarding embryonic stem cell research

Republican voters are divided on embryonic stem cell research, according to a survey of 800 conducted by pollster David Winston, who also conducts surveys for the Republican leadership in the House and Senate. 25% of Republicans said they wanted no government funding of the research, 33% favored the limited funding Bush offers, and 36% wanted expanded funding to cover research on leftover embryos at fertility clinics. The Winston poll was sponsored by a group of centrist Republicans, The Republican Main Street Partnership.[33][34][35]

A June 2004 poll conducted by Opinion Research Corp. on behalf of the Civil Society Institute found that three-quarters of 1,017 adults respondents--including 6 in 10 conservatives--supported former First Lady Nancy Reagan's call for fewer restrictions on the research.^ 

Therapeutic cloning was supported by 59% of respondents in a July 2005 poll of 1,000 adults. Remaining a world leader in medical research was considered important by 95% of respondents. The poll was conducted by Research!America and sponsored by a non-profit organization composed of universities, patient groups and biotech and pharmaceutical companies. [36]

Emerging U.S. state-by-state approach

California voters in November 2004 approved Proposition 71, creating a US$3 billion state taxpayer-funded institute for stem cell research, the California Institute for Regenerative Medicine. Providing $300 million a year, the institute is thought to be the world's largest single backer of research in stem cells, and is expected to substantially increase the pace of embryonic stem cell research.

Several states, in some cases wary of a national migration of biotech researchers to California [37], have shown interest in providing their own funding support of embryonic and adult stem cell research. These states include Connecticut [38], Florida, Illinois, Massachusetts [39], New Hampshire, New Jersey, New York, Pennsylvania, Texas [40][41], Washington, and Wisconsin.

Other states have, or have shown interest in, additional restrictions or even complete bans on embryonic stem cell research. These states include Arkansas, Iowa, Kansas, Louisiana, Michigan, Missouri, Nebraska, North Dakota, South Dakota, and Virginia. (States play catch-up on stem cells, USA Today, December 2004)

Policy debate outside the U.S.

Due to the controversy surrounding embryonic stem cells, many nations around the world have passed legislation regulating research.

In the United Kingdom, the law states that a license may be issued to enable embryos to be created or used for research for the following purposes:

  1. promoting advances in the treatment of infertility,
  2. increasing knowledge about the causes of congenital disease,
  3. increasing knowledge about the causes of miscarriages,
  4. developing more effective techniques of contraception, or
  5. developing methods for detecting the presence of gene or chromosome abnormalities in embryos before implantation,
  6. increasing knowledge about the development of embryos;
  7. increasing knowledge about serious disease, or
  8. enabling any such knowledge to be applied in developing treatments for serious disease.
(Human Fertilisation and Embryology Act 1990 as amended by the Human Fertilisation and Embryology (Research Purposes) Regulations 2001).

As a result of the federal funding restrictions imposed by Congress in the United States, South Korea leads the U.S. in the area of embryonic stem cell research. The UK created the world's first embryonic stem cell bank in May 2004. Because other countries have moved forward with their embryonic stem cell research programs, some in the U.S. have questioned the practicality of the Congressional funding restrictions.

The nations spending the most on stem cell research [42] include the U.S., the UK, South Korea, China, Australia, Israel, Singapore, Argentina, Uruguay, and Sweden. European nations that permit stem cell research also include Switzerland [43], Finland, Greece and the Netherlands. The UK allows the creation of human embryos for stem cell procurement. Countries with regulations allowing cloning for medical research include the UK, Belgium, Singapore and Japan. Recently Brazil has approved a law allowing the use of stem cells in research.

See also

External links


Ethics

Epigenetics

Guides

News

References

  1. ^  National Institutes of Health, "Stem Cell Basics," July 19, 2004.
  2. ^  National Institutes of Health, Stem Cell FAQ, April 13, 2005.
  3. ^  Graham, Judith and Schodolski, Vincent J., "Son of former President Reagan enters the fray with a speech at the Democratic convention." Chicago Tribune, July 27, 2004.
  4. ^  Wildau, Gabriel, "Conservatives echoed Drudge's doctored quotation of Edwards on stem cell research." Media Matters for America, October 13, 2004.
  5. ^  Kang KS, Kim SW, Oh YH, Yu JW, Kim KY, Park HK, Song CH, Han H. "A 37-year-old spinal cord-injured female patient, transplanted of multipotent stem cells from human UC blood, with improved sensory perception and mobility, both functionally and morphologically: a case study." Cytotherapy 2005;7(4):368-73.
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