There was a news report some months back that scientists have created a human embryo from skin cells after converting them into stem cells. Stem cells were earlier reported to be used for grafting organs in animals. These also find mention in some sci-fi literature, as a means to create humans from mature cells.
Stem cell research keeps coming in the limelight once in a while when scientists talk of a prospective cure for a deadly disease by replacing the diseased tissues. Stem cell clinics claim that their therapies can cure diseases that are not curable by other known ways, especially genetic and degenerative diseases.
What are the prospects of stem cell research and therapy? Is it a miracle that can cure all diseases? Will it be possible someday soon to replace an organ rather than treat it for a major disease? Will stem cells be able to make humans immortal? Is stem cell research ethical and safe?
What is a stem cell?
The stem cell is a cell that can divide into new cells but does not have a specialized function in the body. In looks, the stem cell is plain – like a mud ball – while other cells have fancy shapes. For example, nerve cells have a star shaped body and a long tail, muscle cells are cylindrical with tapering ends, and cells in the top layers of the skin are flat like tiles.
We know that all cells have a purpose – nerve cells transport messages, muscle cells contract and expand so as to create motion, skin cells protect the body form elements. So, why should stem cells exist at all?
The answer is: the stem cell is the mother of every cell in the body. It gives birth to a baby cell, which – depending on many factors – turns into a nerve cell or a muscle cell or a cell that would secrete acid in the stomach.
When a baby is conceived, the zygote (=the egg cell, after being fertilized by a sperm) quickly divides into a ball of cells. These cells look alike but soon, based on the genetic information contained in them, differentiate into different types of tissues that eventually give rise to different organs. So, at an early stage of foetus formation, there are cells that do not have a specialized function, but they give rise to new cells that then acquire specialized form and function. These are embryonic stem cells.
When all organs have formed, differentiation from a centralised cell mass is not needed. However, cells in different organs keep dying and need to be replaced by new cells. In most cases, specialized cells do not replicate; so, there are stem cells in all body parts to do that job.
In humans, stem cells are also concentrated in some body parts. Bone marrow is one such place where stem cells keep creating new blood cells. A layer of stem cells under the skin keeps making new cells to replace the surface cells that are routinely shed off as dead skin. Umbilical cord (=the cord that connects the mother with the foetus) is another important place where stem cells are concentrated. A type of stem cells (called mesenchymal stem cells) are found throughout the body, and have the potential to generate cartilage, bone, fat and possibly muscle tissues.
Stem cell journey from body to lab to clinic
It is because of these properties (non-specialized form and capacity to divide into new cells), stem cells have the capacity to grow into any tissue (or the tissue they are associated with) in a lab. It has also been possible to extract certain types of cells (e.g. skin cells) and induce in them the properties of a stem cell. This opens the field of numerous possibilities for treating diseases. This can also kill illegal organ trade, which is wide-spread because healthy organs are difficult to procure.
At a basic level, stem cell therapy can be like organ or tissue transplant in the same person, e.g. hair and skin transplant in case of hair loss and burn injury. It is also possible to graft tissues when bone, skin or cornea of the eye are damaged, and the stem cells of these tissues are able to produce the desired specialized cells.
A slightly more risky surgery involves injecting into the patient’s body stem cells from a donor. Like organ transplants and blood transfusion, this has the risk of the recipient’s body not fully accepting the donated cells, but when it is a case of life-or-death, such a risk looks small, isn’t it?
A more advanced use of stem cells is to create a healthy tissue, or even a full organ, in the lab and replace the diseased tissue or organ with it. If stem cells of the same person are to be used, the process is straight-forward: extract stem cells from the patient, grow them in the lab, trigger differentiation to create the desired tissue, and transplant this tissue in place of the diseased one. Such transplant should be very successful as there is no chance of rejection of an organ, which happens when another person’s organ is transplanted. In addition, it looks very ethical because this does not involve dealing with another person’s organs.
It is also possible, and is being actually done at a small scale, to test a drug on the tissues created out of stem cells before administering that to a patient so as to avoid serious side effects. Stem cells can be patient-specific and disease-specific, and thus they make it possible to provide accurate and effective treatment.
There are dozens of diseases in which stem cells can be used for replacement of damaged tissues and generation of new tissues. Naturally, stem cell therapies show a great promise in treatment of genetic and degenerative diseases. At least, that is the promise.
Bone marrow transplant is one of the few established stem cell therapies beyond simple transplants. Bone marrow’s stem cells make blood cells. So, when these get damaged due to a blood disease, cancer treatment such as chemotherapy, or some other reason, a serious health condition develops. Doctors then resort to replenishing the bone marrow with stem cells, usually from a donor. Even after many years in practice, bone marrow transplants often lead to side effects and complications.
Stem cell therapy has also been successful – to varying degrees – in treating some other diseases, including those of liver and heart.
Overall, advanced stem cell research and therapies have not matured yet. Besides the complications arising out of reaction of a body to foreign cells, the cells do not behave exactly the way they are intended to. For example, they may continue to grow after producing the desired result; that leads to formation of tumour.
The example of treatment of Parkinson’s Disease with stem cell therapy would show how the research is progressing and why it is slow. This incurable disease results from the death of a large number of brain cells (neurons), particularly in mid-brain. That leads to loss of many bodily functions and memory. The available treatments are not safe and at best result in temporary relief. Therefore, the idea of using stem cells for treatment of this disease is being explored. For some five years, a lot of research and international collaboration has made it possible to create stem cell therapies in which either the patient’s own cells or those taken from foetus are programmed to generate the type of neurons that are lost in the patient. Experiments have proved successful, but actual treatment is yet some steps away.
The graphic below shows some areas in which research is underway to find use of stem cells.
Stem cell clinics: Creating hype, fleecing people in distress
The field of stem cell therapies is full of promise, and that makes it possible for research labs or clinics with a basic infrastructure to handle stem cells to convince people that they have found a miracle cure, and people under duress find the last hope in them.
In rich societies, stem cell therapies have gained high acceptance because the rich do not mind spending astronomical sums of money on a treatment that promises a cure that other existing therapies don’t.
It is also reported that since the patients of only such diseases that defy mainstream medical treatment undergo stem cell therapy, clinics get away with convincing arguments when the therapy fails or leads to complications. If the patient recovers, which may be due to other factors, that is touted as a success story to get more business.
It may seem ironical, but is becoming true for many branches of clinical specialization in which the research is difficult, time-taking and under severe regulations, technology to exploit it is much more easily available. In the case of stem cells, kits to induce differentiation in these cells are being sold by some companies, which makes it possible for clinics to procure stem cells from the patient or foetal resource, apply differentiation kit to produce the desired type of tissue and transplant it on the patient.
The attraction of stem cell therapies, coupled with strong promotion and targeting by stem cell clinics, has spawned stem cell tourism as a branch of medical tourism, in which inflated packages are offered at discounted rates to lure prospective clients of foreign countries.
It is widely reported in scientific literature that stem cell clinics do not often have the right technology for therapy that they claim mastery on. Though stem cells of all types cannot work in all tissues, many clinics tell their clients that their stem cells can treat a wide variety of diseases, and that stem cells once injected into the body have a way to reach the diseased organ and heal it.
It is also suspected that even experimental technologies are being touted as effective, proven, treatments while such experiments have not undergone a thorough process of clinical trials and validation that all human medicines and procedures need to pass through. Clinics are reported to be charging in the range of $30,000 dollars (about 25 lakh rupees) for the [experimental] treatment, and this does not include costs on travel, post-operative care, etc. During COVID-19, some clinics are said to have offered treatment using stem cells, though no such treatment has yet been approved anywhere.
Serious researchers are also not sure about the precautions being taken by most clinics, even for therapies found to be effective. They invite attention to the fact that stem cell cultures are highly prone to contamination if not sourced properly and handled with extreme care.
The International Society for Stem Cell Research [ref 2] has to say this, “…there has been a proliferation of unregulated stem cell clinics providing unproven treatments for patients with a variety of diseases, injuries, and congenital defects. With more than 700 stem cell clinics in operation within the United States alone, and many more worldwide, patients have increasing access to risky, untested options for serious illnesses… These clinics, largely unregulated and unconstrained by ethical guidelines, are thriving, despite the fact that their practices have not been proven to be safe or effective, and in some cases, have caused harm.”
Sadly, there are many public reports of people suffering serious injuries and even death after stem cell therapies in many countries, but neither national governments nor the WHO have tried to effectively regulate stem cell clinics.
The potential: from earth to space!
Let me come back to the potential of stem cells again, because the unethical practice carried out by stem cell clinics does not diminish the possibilities they offer.
In future, stem cell research might lead to astounding outcomes that we can only imagine today.
To appreciate that, let us briefly see how the research in this field is progressing.
The use of stem cells in Organ-on-Chips technology (use of small machines that mimic real organs) is opening a new field of fast drug testing and development of new treatments.
Using stem cells, complex cell cultures are also being created in the lab, in which more than one type of cells are grown. Called assembloids, these can mimic the way organs function, and, therefore, can be used for understanding the functioning of organs and in turn treating them in new ways.
Scientists have been able to create tissues of the heart, eyes, spinal cord, etc., in the lab, which promises to treat malfunctioning and deformities of these organs. Human stem cells have also been successfully grown on tissues of other animals, which paves the way for producing organs on a big scale in the lab.
Cell-masses resembling early stages of human embryos – blastoids – have recently been generated in labs. In another experiment this year, human stem cells were injected into monkey embryos, creating hybrid embryos.
Stem cells have also been taken to space to study. In fact, there is a dedicated stem cell lab in the International Space Station. Such research is trying to find if stem cells can be cultured in space better than on earth, the impact of microgravity and other factors present in space, and the use of stem cells for space travel in future.
Think of these possible scenarios, ranging from what is expected in the coming years to what is still scientific fiction:
- Stem cells provide ways to fight pathogens and quickly check pandemic diseases from spread.
- It is possible to induce regeneration of tissues and organs by injecting specific stem cells.
- Lab-created organs are available on demand.
- A person who loses most of his/ her original organs due to disease or old age or accident can live with lab-created organs.
- Humans can have tissues drawn from other animals.
- It is possible to create humans out of tissues: without sexual reproduction. (It goes even beyond cloning, which was used for creating Dolly, a sheep, from an egg and another cell.)
- Humans breed colonies in outer space with the help of stem cells.
Foetal tissues are one of the most important stem cell resource for research as well as treatment. However, since foetus is a living organism – a not-yet-born human – and killing it (deliberately and without its consent) has ethical dimensions. Many countries have put restrictions on its use. In the US, funding for research involving human foetus was banned in 2019 but some of it has been reversed by the Biden administration.
The biggest ethical issue in foetus donation for research is whether informed consent of the donor was taken. Putting patients into serious conditions using technology still under development is also unethical by all means. Use of stem cells from foreign institutions is fraught with legal and political issues as well.
One ethical question in stem cell research targets the entire humanity, though it might look far-fetched at present: the creation of unnatural body parts, and eventually humans. The recent creation of hybrid embryos and early-stage embryos in the lab have raised eyebrows, and this has divided the scientific community and authorities on ethical grounds.
As the research in this field was getting stymied due to an international consensus of not growing human embryos in the lab beyond 14 days, the limit was recently lifted, which has led to questions whether this decision puts technology before ethics.
Concern is often raised that sciences that manipulate natural life at a deep level, such as stem cell research and genetic engineering, can go out of hand, if not controlled from the beginning. Diehard researchers call such concerns as regressive and flawed, leading to fear-mongering against a branch of science with huge potential for human well-being.
I take the liberty to leave you in the lurch. Here is a resource, and a technology to harness it, that can greatly help the humanity… but if it goes out of hand, it can produce a monster, which annihilates the humanity without giving it the time to repent for its own indiscretion.
- Bone marrow transplant
- Communicating About Unproven Stem Cell Treatments to the Public
- ISSCR Guidelines
- Parkinson’s Disease
- Private clinics’ peddling of unproven stem cell treatments is unsafe and unethical
- Stem cell
- Stem cells
- Stem cells: highlights from research
*Manoj Pandey is a former civil servant. He does not like to call himself a rationalist, but insists on scrutiny of apparent myths as well as what are supposed to be immutable scientific facts. He maintains a personal blog, Th_ink
Disclaimer: The views expressed in this article are the personal opinion of the author and do not reflect the views of raagdelhi.com which does not assume any responsibility for the same.