Stem cell research
|How the sausage is made|
Stem cell research proposes to use stem cells to repair or replace damaged tissues in order to treat an extremely wide range of conditions, including severed spinal cords, non-functioning endocrine glands, diabetes, cancer, heart disease, various types of brain damage, and many other conditions.
This article predominantly looks at the social side of the issue, rather than detailing current scientific research or scientific discussions.
What are stem cells?
Most cells in the human body are considered to be "differentiated", or specialized at one task. For instance, red corpuscles are specialized in oxygen delivery, astrocytes in delivering nutrients to neurons, osteoclasts in dissolving bone, etc. The value of stem cells comes from the two properties which define them. First, they exhibit self-renewal (they can divide repeatedly into more stem cells). Second, they exhibit potency, which is the ability to differentiate into any of a wide range of different tissues. Potency is measured on a scale:
- Totipotency — Ability to become any type of human tissue, including extraembryonic tissues like the placenta
- Pluripotency — Ability to become any type of tissue found in an adult human
- Multipotency — Ability to become any one of many, but not all, types of tissues found in an adult human
- Unipotency — Ability to become only one type of cell found in an adult human (your own)
- (There could be a possible fifth level, "nullopotency", where the cell cannot reproduce, e.g. osteoblasts and red corpuscles)
There are two kinds of stem cell: adult stem cells and embryonic stem cells. Adult stem cells are usually only multipotent or even unipotent, whereas some embryonic stem cells are pluripotent.
Stem cells are unique cells that have an unspecialized purpose. Stem cells have three important uses. They can replace damaged cells in a person's body. This means that they can cure a person's blindness, paralysis, and disease. They are also used in testing the safety and quality of pharmaceutical drugs. Instead of testing new drugs on people, stem cells eliminate all the risk of side effects and dangers. Lastly, they can help scientists gain a better understanding of how diseases develop. By studying how certain cells become defective with a disease, they can figure out how the disease develops, thereby finding a cure for the disease.
Examples of research
It is hoped that stem cells can provide cures for many illnesses as well as loss of body tissue from things like traumatic burns.
Much of the primary research is focused on attempting to revert normal adult stem cells into embryonic stem cells, since this would also allow a much greater range of treatments using one's own cells and potentially negate the need to take immunosuppressants for life. It also has the side benefit of avoiding the Religious right's whining and moaning about using embryonic stem cells.
The use of adult stem cells has made its way into (experimental) clinical practice, for a number of therapies. With the exception of bone marrow transplantation in cancer patients, only stem cells harvested from the patient's own body are used — not for political or ethical reasons, but because grafts of ones own cells have almost no chance of organ rejection.
In 2012, Yamanaka and Gurdon won the Nobel Prize in Medicine for discovering a way to turn ordinary skin cells into stem cells. Depending on how functional these "manufactured" stem cells are, when compared with normal adult stem cells or embryonic stem cells, many new avenues of research may have been opened up.
The use of human embryonic stem cells has evoked ethical concerns from anti-abortion advocates, because blastocyst-stage embryos are destroyed in the process of obtaining the stem cells. The embryos from which stem cells have been obtained are produced through in-vitro fertilization. Those who consider pre-implantation human embryos to be human beings generally consider such work to be morally wrong, because they assert that human life begins at the moment that an egg cell has become fertilized. Therefore, those who oppose embryonic stem cell research believe that the extraction of embryonic stem cells violates the sanctity of life and is tantamount to murder.
Others may accept the use of human embryonic stem cells because:
- They may not regard the blastocysts to be human persons with right to life.
- More than a third of zygotes do not implant after conception. Thus, far more embryos are lost due to chance than are proposed to be used for embryonic stem cell research or treatments.
- It is known that none of the cells of the inner cell mass are exclusively destined to become part of the embryo itself — all of the cells contribute some or all of their cell offspring to the placenta, which has not been accorded any special legal status.
- In vitro fertilization generates large numbers of unused embryos. Many of these thousands of embryos are slated for destruction. Using them for scientific research utilizes a resource that would otherwise be wasted.
The divergence of views on this issue is illustrated by the fact that the use of human embryonic stem cells is allowed in some countries and prohibited in others. In USA, during the Bush years, Federal funding for new lines of embryonic stem cell research was banned, but research continued on adult stem cells.
Transplantation of animal stem-cells into humans, a/k/a Live cell therapy, is on-offer in quack clinics across the globe, but cells from a different species would not be tolerated by the host's immune system.
Stem cell research's high-profile public image has led to both popular and media misunderstanding about its effectiveness, and, more concerningly, to fraud within the field. On average, papers on the topic are withdrawn over twice as often as papers in other areas of biomedical research.
Craziness and conspiracy
A lot of opponents of stem cell research appear totally unhinged, making opponents of GMOs or abortion look like rational, evidence-based thinkers. The actor Michael J Fox was accused by radio presenter Rush Limbaugh of faking symptoms of Parkinson's disease to get funding for stem cell research in 2006.
A 2017 academic study of "fake news" on anti-stem cell research websites found "numerous articles made statements promoting fear and mistrust of medical practices, government and specific politicians" and that "the stem cell news created on these websites is alarming and could have repercussions for the general public seeking sound scientific information", especially as "many articles seemed to be structured for revenue generation" rather than presenting actual facts about stem cell research. The researchers recorded headlines on stem-cell-related stories including "Obama approves plans to create animal-human hybrid monsters", "McDonald's & Burger King using dead aborted human fetuses in their food?" and "Obama Openly Promotes the Murder of Babies and Harvesting of Live Babies’ Organs".
On the other hand, there's also a conspiracy theory that Big Pharma is blocking stem cell research so it can go on selling drugs to people who might be saved by stem cells; this theory is being pushed at least partly by dodgy clinics offering dubious stem cell therapies.
Safety and efficacy
There is an enormous amount of hype about stem cell cell treatments. Prior to 2012, treatments for US patients were primarily limited to medical tourism. Starting in around 2012, a South Korean named Celtex opened a clinic in the US, but was quickly warned by the FDA that their products must first be approved for use on humans. In response, Celtex moved its clinic to Mexico, but by 2014-2015 many companies were offering an expensive and unproven form of resembling stem cell treatments.
As of 2020, the only FDA-approved medical treatment involving stem cells is for certain cancers and blood disorders. What the clinics offer instead are treatments for a wide range of ailments (mostly for orthopedic and pain, with knee treatments being the most common) using a reinjection of the patient's own cells from one place to another with minimal manipulation. To do otherwise would make the treatment an unapproved drug according to FDA regulations. The clinics that offer this treatment typically call it treatment with 'mesenchymal stem cells' (typically from bone marrow or fat tissue). This is a misnomer because there is no evidence that these unmanipulated cells are pluripotent (i.e., that they can become other types of cells in the body), and it has been proposed that this be renamed to 'mesenchymal stromal cells'. In contrast, approved and experimental medical treatments strip off extraneous cells from the fat, leaving only the pluripotent cells. As of 2020, there have been few studies on unapproved treatments, and those that exist have not been particularly promising.
A 2018 review of adverse events from unproven treatments found 35 cases. Adverse events included cancer, neurological, infection, blindness, fever, autoimmune reaction, cardiovascular events, cerebrovascular events, pneumonia, and death. The authors believed that the true number of adverse events was much larger due to a lack of systematic reporting.
- Evidence-based medicine
- Politicization of science
- John R. Brinkley — a quack doctor who transplanted goat testicles into men in the 1920s
- Dr Con Man: the rise and fall of a celebrity scientist who fooled almost everyone
- Radio host apologises for claim Michael J Fox faked symptoms, The Guardian, Oct 26, 2006
- Fake news portrayals of stem cells and stem cell research, Alessandro R Marcon, Blake Murdoch & Timothy Caulfield, Regenerative Medicine, VOL. 12, NO. 7, https://doi.org/10.2217/rme-2017-0060
- Predatory clinics push stem cell secret society, deep state conspiracy theory, Paul Knoepfler, Knoepfler Lab Stem Cell Blog, UC Davis School of Medicine, Jan 19, 2018
- Stem cell clinics’ much-hyped treatments lack scientific support: Patients are getting injections to relieve knee pain and more, with too little research on safety and effectiveness by Laura Beil (January 30, 2020 at 6:00 am) Science News.
- Concise Review: A Comprehensive Analysis of Reported Adverse Events in Patients Receiving Unproven Stem Cell-Based Interventions by Gerhard Bauer et al. (2018) Stem Cells Translational Medicine 7:676–685. doi:10.1002/sctm.17-0282.