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Stem cells - the promise and the reality
The Star (Malaysia) ^ | December 7, 2008 | DR MILTON LUM

Posted on 12/08/2008 1:59:29 AM PST by neverdem

Despite the promise of stem cell therapy, little has been achieved thus far.

STEM cells have been used for treating patients with leukaemia who relapsed and did not respond to chemotherapy and radiotherapy since the late 60s. These patients had bone marrow transplants.

However, media and public interest was only fired up after the announcement of the birth of Dolly, the sheep which was the first mammalian clone from adult cells, on July 5, 1996. Since then, interest has continued unabated, with research findings continuing to find their way into the media, with all its attendant hype.

Stem cells leaped into the public imagination after the hype following the conception of Dolly, the sheep which was the first mammalian clone from adult cells. - Reuters

There is much hope on offer. The impression conveyed is that stem cells could provide the cure for just about any and every condition one can think of. This article sheds some light on the promise and the reality of the application of stem cells in medicine.

Stem cells are unique

The organs and tissues of the human body comprise cells that need constant replacement as a result of use or disease. The body needs to constantly make cells to maintain its various functions, and stem cells play an important role in this respect.

All humans start life when a sperm fertilises an egg. The fertilised egg, which is called a totipotent cell, contains unique genetic information, from which all the cells in the body are made. After a few further cell divisions, some cells become the trophoblast, which develops into the placenta, and the inner cell mass, which develops into the foetus.

There is a limited time frame during which the inner cell mass has the potential to become all types of cells of the body. These cells are called pluripotent cells i.e. they are able to form more stem cells or any type of body cell.

Stem cells are undifferentiated cells, without any special properties and functions. They possess the unique ability to produce both copies of themselves and specialised cells on each occasion they divide. Stem cells are vital for the maintenance of body parts that undergo continuous turnover, for example, blood, skin and intestine, and muscles which are damaged.

Some specialised cells, for example, blood and muscle, cannot make copies of themselves by cell division. Stem cells can produce these specialised cells through differentiation. The ability of a stem cell to produce any cell type is gradually reduced as one gets older.

In short, stem cells are master cells i.e. cells from which all other cells with specialised functions are created.

Different stem cells

There are different types of stem cells i.e. embryonic and adult stem cells, induced pluripotent stem cells (iPS cells), embryonic germ cells and amniotic fluid stem cells.

Embryonic stem cells are obtained from the inner cell mass of the five to six days old embryo at the blastocyst stage, when there are only about 50 to 150 cells. Such embryonic stem cells are pluripotent and they have the highest potential for regeneration or repair of diseased tissue and organs.

However, the use of embryonic stem cells is dominated by moral and ethical controversies.

Adult stem (also called tissue stem) cells are derived from adult and foetal tissue. They are found in small numbers in most tissues, for example, bone marrow, the placenta and umbilical cord. A more precise term for these cells is somatic stem cell (soma means body). They are able to form cells of that particular tissue, for example, stem cells in the skin will give rise to new skin cells replacing old or damaged skin cells.

Recently, there are research suggestions, which is still in its infancy, that the adult stem cells are more versatile than previously thought in that they are able to create unrelated types of cells, for example, bone marrow stem cells may be able to create muscle cells.

Scientists have recently manipulated the expression of certain genes in somatic cells, thereby “reprogramming” them back to a pluripotent state. These cells are called induced pluripotent stem cells (iPS cells). The scientists reported that they had created stem cells from skin cells in laboratory studies. The reprogramming involves processes that may not be safe for humans. Whether iPS cells can be as useful as embryonic stem cells is unknown.

Embryonic germ cells are derived from the part of the embryo or foetus that will eventually form the testicles or ovaries. They can become any type of cell, just like embryonic stem cells.

However, there is limited research on these cells as the embryos or fetuses used have to be aborted. The use of these cells may be limited as they have a tendency to differentiate spontaneously.

Amniotic fluid stem cells are derived from the fluid in the sac that surrounds and protects the developing foetus. The cells have been found in pregnant women who had amniocenteses for diagnostic reasons, for example, chromosomal abnormalities. The potential of these cells is yet to be understood.

The promise

Stem cell transplants refer to the replacement of damaged or diseased cells with stem cells. It is similar to organ transplantation except that cells are used instead of organs.

Stem cells are grown in laboratories and manipulated to produce specific, specialised cells. The process may involve changing the material in which the stem cells are grown or injecting genes into the cells. The cells grown are implanted into the relevant body part of the affected person. The theory is that the implanted cells will replace the damaged or diseased cells.

Stem cell transplants have been done since the late 1960s with successful treatment of selected groups of patients, for example, relapse in acute and chronic leukaemia, myeloproliferative disorders, bone marrow failure (aplastic anaemia), some genetic metabolic disorders and haemoglobinopathies.

The two most common reasons for the use of stem cell transplants are selected patients who have relapse in acute lymphoblastic leukaemia and advanced neuroblastoma.

The efficacy of stem cell transplants is dependent on the introduced cells getting to where they are required to replace or heal cells that have been damaged. They should not contain undifferentiated embryonic stem cells. The introduced cells, the patient or both have to be treated so that the patient’s immune system does not attack the introduced cells.

The areas of stem cell research are:

·Studies on development

·Studies on disease

·Studies of its potential in the treatment of diabetes, heart disease, Parkinson’s disease, stroke, Alzheimer’s disease, spinal cord injury, muscle dystrophy

·Testing new medical treatments

The reality

Data on stem cell therapies are diverse, with few comprehensive data on treatments on patients. However, there is comprehensive data on umbilical cord stem cell transplants recorded by Eurocord, an international registry started by the European Union in 1995 (website: www.eurocord.org).

During the period 1988 to February 2007, it recorded data from 3,372 umbilical cord transplants in 43 European and non-European countries, of which 2,965 were unrelated donor and 359 related donor transplants (allogeneic) but only three were autologous transplants.

Allogeneic transplants are collected from a related or unrelated donor and transplanted into the patient after treatment of the cells to reconstitute the bone marrow.

On the other hand, autologous transplants are collected from the patient before treatment and then re-infused after treatment to reconstitute the bone marrow. The former are obtainable from public cord blood banks and the latter from commercial cord blood banks.

The public cord blood bank receives cord blood from voluntary donors. The blood are typed and stored for anyone who needs to use it. The bank operates as a not-for-profit organisation. When there are requests for the cord blood for use in specific patients, there will be a fixed charge to defray the expenses incurred in the collection, typing and storage of the cord blood.

The private cord blood banks cater for individuals. Parents have to pay registration, collection and storage fees. The banks operate as business concerns and there is competition for clients who are willing to pay for such services.

If one were to view the websites of commercial cord blood banks, one would find a long list of diseases that can be treated by stem cells. Most of these diseases can only be treated with allogeneic transplants, but there is no explanation of its difference from autologous transplants in most of these websites.

It is not common for commercial cord blood banks to inform their clients that the amount of stem cells harvested from umbilical cord blood is insufficient for stem cell or bone marrow transplant if the child grows to more than 45 kg. As such, certain childhood cancers, for example, the common acute lymphoblastic leukemia, is unlikely to benefit much from autologous transplants.

In a comprehensive review in Nature Reviews Cancer (June 12, 2008 edition), Micheal Sullivan pointed out that there are only three single case reports published of autologous transplants sourced from commercial cord blood banks in the past 15 years. He stated: “Although commercial cord banks promote cord banking to parents for the possible use for the treatment of childhood leukaemia, in 15 years of commercial cord blood banking only one case of autologous cord blood transplantation for acute lymphocytic leukaemia has been reported in the medical literature and that was in 2007.”

Sullivan also worked out the likelihood of needing a stem cell transplant for childhood leukaemia and neuroblastoma based on data from the Collaborative European cancer registry. Both conditions are the commonest reasons for stem cell transplants.

The likelihood of needing an allogeneic transplant in childhood leukaemia is 1 in 22,000. It should be remembered that autologous transplants is not routinely indicated in leukaemia relapse. The likelihood of needing an autologous transplant in neuroblastoma is 1 in 15,000.

Should one store baby’s umbilical blood for later use in life?

This is a question that confronts many prospective parents in Malaysia. The promise of stem cell transplants may not be far away. However, the promotional material from some commercial stem cell banks gives the impression that it is already in routine use.

It is not!

The materials also appeal to prospective parents’ hearts with statements like “The best gift you can give your baby”, “Cord blood cells may literally be life saving to your child or family member”, “Bio-insurance for your child’s future health” etc.

To answer the question, it is worthwhile taking heed of statements from prominent authorities. The European Commission’s Group on Ethics in Science and New Technologies (EGE) report on the ethics of private umbilical cord banking stated: “The legitimacy of commercial cord blood banks for autologous use should be questioned as they sell a service, which has presently, no real use regarding therapeutic options. Thus they promise more than they can deliver. The activities of such banks raise serious ethical criticisms.

“If commercial banks are allowed (in any EU member state), appropriate information should be given to consumers willing to use their services, including the fact that the likelihood that samples may be used to treat one’s child is currently negligible, that future therapeutic possibilities are of a very hypothetical nature, and that up until now there is no indication that the present research will lead to specific therapeutic applications on one’s own cord blood cells.

“… information should be particularly explicit, that the auto conservation has little value in the current state of scientific knowledge. This information should be made clear on all media, including Internet, and in any contracts linking commercial banks to their customers.”

The Royal College of Obstetricians and Gynaecologists (RCOG) of the United Kingdom stated: “The RCOG strongly supports the concept of a NHS Cord Blood Bank for allogeneic storage of donated cord blood and would like to see it well funded. However, it remains unconvinced of the benefit of personal commercial banking for low-risk families.”

Similar statements have been made by the Society of Obstetricians and Gynaecologists of Canada: “Commercial cord blood banks offer mothers the opportunity to store their babies’ umbilical cord blood stem cells indefinitely, in case the infant develops illness for which stem cell transportation may be indicated.

“At present, it is not certain how long frozen cord blood will remain viable. It is difficult to estimate the likelihood that an autologous cord blood donation will be used. It has been estimated that the risk of a child needing a bone marrow transplant before his or her 10th birthday is between 1:200,000 and 1:10,000. According to available figures, less than 5% of privately stored cord blood has been used clinically, and it has been estimated that the autologous use of umbilical cord blood occurs in 1:20,000 collections.”

Collection and long-term storage of umbilical cord blood for autologous donation is not recommended because of the limited indications and lack of scientific evidence to support the practice.

Commercial cord blood banks should be carefully regulated to ensure that promotion and pricing practices are fair, financial relationships are transparent, banked cord blood is stored and used according to approved standards, and parents and care providers understand the differences between autologous versus allogeneic donations and private versus public banks.”

The Malaysian Health Ministry states: “The establishment of public and private cord blood banks shall be in accordance with national standards and guidelines and subjected to Ministry of Health approval.”

The standards and guidelines have yet to find its way into the public domain.

Conclusions

There is much enthusiasm among researchers of the potential of stem cell therapies. While much has been achieved, there is still an enormous amount of scientific work that needs to be done to realise the potential of a concept that is relatively simple but complex in translating theory into practice.

When there are limited or no options in the treatment of certain chronic or terminal conditions, hope can be an addictive drug. Doctors and regulators have the task of tempering hope with realism. To indulge in hype about stem cells as if tomorrow has arrived today cannot be considered responsible by any stretch of the imagination.

The implementation of the Health Ministry’s National Standards for Stem Cell Transplantation will hopefully go some way towards protecting the patients’ interests.

> Dr Milton Lum is Chairperson of the Commonwealth Medical Trust. This article is not intended to replace, dictate or define evaluation by a qualified doctor. The views expressed do not represent that of any organization he is associated with. The views expressed are those of the writer and readers are advised to always consult expert advice before undertaking any changes to their lifestyles. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.


TOPICS: Culture/Society; Editorial; News/Current Events
KEYWORDS: health; regenerativemedicine; stemcells
Nothing with clinical usefulness has been achieved with embryonic stem cells. You'll find a dispute with adult stem cells potential for regenerative medicine. IIRC, there are 70 - 80 indications or clinical trials using adult stem cells.
1 posted on 12/08/2008 1:59:29 AM PST by neverdem
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To: Coleus; Peach; airborne; Asphalt; Dr. Scarpetta; I'm ALL Right!; StAnDeliver; ovrtaxt; ...

This is a relatively good review article on stem cells, IMHO.


2 posted on 12/08/2008 2:06:15 AM PST by neverdem (Xin loi min oi)
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To: neverdem

Adult stem cells work. I got to donate for a little boy with leukemia 2 years or so ago, and finally got some information about him recently...he’s doing quite well.

Reasonably easy procedure...5 days of shots and on the 5th they filter the stem cells out of your blood. Wasn’t any rougher than donating blood really.


3 posted on 12/08/2008 2:35:22 AM PST by Fire_on_High (Regroup!)
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To: neverdem

ping


4 posted on 12/08/2008 2:36:58 AM PST by Bellflower (A Brand New Day Is Coming!)
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To: neverdem

ping


5 posted on 12/08/2008 2:37:29 AM PST by Bellflower (A Brand New Day Is Coming!)
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To: neverdem

Thanks for the ping.

BTTT


6 posted on 12/08/2008 4:40:13 AM PST by Dr. Scarpetta
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To: neverdem

My cynical view of stem cell research evolved from reading results of their work. I summarized it for unwashed that had difficulty comprehending facts in the physical world.

The stem cell researcher asserts: We will heal the sick, we will make the desert bloom, we will resurrect the dead, just sent us MONEY.


7 posted on 12/08/2008 4:57:04 AM PST by Citizen Tom Paine (Swift as the wind; Calmly majestic as a forest; Steady as the mountains.)
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To: neverdem

The media likes to pretend that conservatives like me are against stem cell research. Not true at all. What I’m against is the use of stem cells from aborted babies, the practice of concieving a new human being for the purpose of killing it and then selling its body parts, or creating a new human being in a test tube for the sole purpose of using it for research and then discarding it.


8 posted on 12/08/2008 4:59:36 AM PST by libertylover (The problem with Obama is not that his skin is too black, it's that his ideas are too RED.)
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To: neverdem

for later


9 posted on 12/08/2008 5:30:32 AM PST by Desdemona (Tolerance of grave evil is NOT a Christian virtue (I choose virtue. Values change too often).)
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To: libertylover

stem cells from aborted babies need to be outlawed.


10 posted on 12/08/2008 6:09:31 AM PST by Vaduz
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To: Fire_on_High

As someone who has received a bone marrow transplant, I want to say “Thank you and God bless you for donating!”

17 years cancer free and counting!!!


11 posted on 12/08/2008 6:35:17 AM PST by airborne (God answers all prayers. Just some times the answer is "no".)
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To: neverdem

Thanks for the ping!


12 posted on 12/08/2008 8:03:46 AM PST by Alamo-Girl
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