STEM CELL RESEARCH (ISLAMIC VIEW)
"Stem
Cells" are a group of the cells that have the remarkable potential to
develop into many different types in the body. Serving as a sort of repair
system for the body they can theoretically divide and replenish other cells as
long as the person or animal is alive.
Stem
cells have potential in many different area of health and medical research. To
start with, studying stem cells will help us to understand how they transform
into the dazzling array of specialized cells that make us what we are. Some of
the most serious medical conditions, such as cancer and birth defects, are due
to problems that occur somewhere in the process. A better understanding of
normal cell development will allow us to understand and perhaps correct the
errors that cause these medical conditions.
Another
potential application of stem cells is making cells and tissues for medical
therapies. Today, donated organs and tissues are often used to replace those
that are diseased or destroyed. Unfortunately, the number of people suffering
from these disorders far outstrips the number of organs available for
transplantation. Stem cells offer the possibility of a renewable source of
replacement cells and tissues to treat myriad diseases, conditions, and
disabilities including Parkinson's and Alzheimer's diseases, spinal cord injury,
stroke, burns, heart diseases, diabetes, osteoarthritis and rheumatoid
arthritis. There is almost no realm of medicine that might not be touched by
this innovation.
What
is a stem cell?
At
the dawn of human life, a sperm fertilizes an egg to create a single cell
destined to become a child. As development commences, that cell begins to divide
producing after five or six days a small ball of a few hundred cells called a
blastocyst. Blastocyst (a pre-implantation embryo), consists of 150 cells: outer
cells called trophectoderm and making placenta, and cluster of about 30 cells in
the interior called inner cells or embryonic stem cells (ESC) which give rise to
the multiple specialized cell type that make up the fetus. There is a fluid
filled cavity called blastocell that separates outer cells from inner cells
within the blastocyst.
ESC
are undifferentiated primitive cells with the ability to a) multiply and renew
themselves for long periods (proliferation), and b) differentiate into specific
kinds of cells under certain physiologic or experimental condition
(differentiation).
Where
do the stem cells come from?
a)
Embryonic stem cells (ESC), are derived from the inner cell mass of the
blastocyst (a very early embryo).
b)
Embryonic Germ Cells (EGC), are collected from fetal tissue at a somewhat later
stage of development (from a region called the gonadal ridge).
c)
Adult stem cells (ASC), are derived from mature tissue. Even after complete
maturation of an organism, cells need to be replaced (blood, muscle, connective
tissue and to a lesser degree nervous system cells).
What
classes of stem cells are there?
a)
Totipotent stem cells are cells that can give rise to a fully functional
"organism" as well as to every cell type of the body (fertilize egg).
b)
Pluripotent stem cells are capable of giving rise to virtually any
"tissue" type but not to a functioning organism (ESC).
c)
Multi potent stem cells are more differentiated cells and thus can give rise
only to a limited number of tissues (adult stem cells).
Knowledge
about stem cell science and potential application has been accumulating for more
than 30 years. In the 1960's it was recognized that certain mouse cells had the
capacity to from multiple tissue types, and the discovery of bona fide stem
cells from mice occurred in 1971. In 1998 teams at University of Wisconsin under
leadership of James A. Thomson and at John Hopkins University under leadership
of John Gearhart, reported on how to culture the human ESC's, launching a new
era of cell engineering.
Procedure
for generating human ESC are as follows:
1.
Culture blastocyst
2.
Remove outer layer
3.
Add chemical to desegregate inner cell mass
4.
Transfer inner cell mass to a new well
5.
Add selective differentiation factors
6.
Deliver differentiated cells to damaged tissue
Discovering
the signals that induce the formation of specific cell types has been a very
difficult task that is still ongoing. Some methods available to control
differentiation of ESC's, in order to obtain specific cell groups examples are:
a)
Changing the chemical composition of the culture medium.
b)
Altering the surface of the culture disk.
c)
Modifying the cells by inserting specific genes. Leukemia inhibiting factor is
the key biological agent.
Scientific arguments against the use of ESG as a treatment for disease and injuries are as follows:
a)
Immunological issues causing rejection of transplanted cells.
b)
Failing to replicate the full range of normal developmental factors in a culture
dish.
c)
Lack of sufficient evidence from animal studies to warrant a move to human
experimentation.
Solution to the problem of immune rejections:
a)
Genetic engineering of ESC's to alter their immune characteristics,
b)
Therapeutic cloning
c)
Embryo banking
d)
Using patients own adult stem cells
Adult Stem Cells (ASC)
From
post-embryonic development through the normal life of any organism, certain
tissues of the body require stem cells for normal turnover and repair. The most
well-known example of ASC are hematopoietic stem cells of blood. More recently,
mesenchymal stem cells (MSC) required for the maintenance of bone, muscle, and
other tissues have been discovered. ASC's are multi potent, they are restricted
and unable to generate full range of mature cell types. However, the MSC is in
fact an excellent example of the potential for use of stem cells in human
therapeutic procedures ASC are capable to differentiating into:
a)
Hematopoietic stroma cell give rise to all types blood cells.
b)
Bone marrow stromal cells give rise to osteocytes, chrondocytes, adipocytes,
etc.
c)
Neural stromal cells give rise to neurons, astrocytes, and oligofendrocytes.
d)
Epithehial ACS in the lining of digestive tract give rise to goblet cells etc.
e)
Skin ACS give rise to keratinocytes, hair follicles and to epidermis.
MSC's
are capable of differentiating into bone, cartilage, muscle, fat and a few other
tissue types. Their use for bone and cartilage replacement into undergoing FDA
approved clinical trials at the present time.
Certain
ACS are pluripotent and could differentiate into multiple cell types for
example:
a)
Hematopoietic ACS into three major types of brain cells.
b)
Bone marrow stromal cells into cardiac and skeletal muscles.
c)
Brain ASC into blood and skeletal muscle cells. This ASC capability is called
"PLASTICITY," if the mechanism that is responsible for ASC plasticity
can be identified and controlled, existing stem cells from a healthy tissue
might be used to repair a diseased tissue.
Adult-derived
stem cell therapies will complement, but cannot replace, therapies that may be
eventually obtained from ES cells. They do have some advantages. For example,
adult stem cells offer the opportunity to utilize small samples of adult tissues
to obtain an initial culture of a patient's own cells for expansion and
subsequent implantation (this is called an autologous transplant). This process
avoids any ethical or legal issues concerning sourcing and also protects the
patient from viral, bacterial, or other contamination from another individual.
With proper manufacturing, quality control and testing, allogenic adult stem
cells (cells from a donor) may be practical as well. Already in clinical use are
autologous and allogenic transplants of hematopoietic stem cells that are
isolated from mobilized peripheral blood or from bone marrow by positive
selection with antibodies in commercial devices. In general, there is less
ethical concern over their initial source. Additionally, since they normally
differentiate into a narrower set of cell types, directing them to a desired
fate is more straightforward. However, many cells of medical interest cannot, as
of yet, be obtained from adult-derived cell types. Production of large numbers
of these cells is much more difficult than is the case for ESC's cells. Based
upon our present knowledge base, it appears unlikely than human adult stem cells
alone will provide all of the necessary cell types required for the most
clinically important areas of research.
Therapeutic Cloning "Embryo Cloning":
The
goal is the harvest stem cells for research and to tract disease. The following
steps are taken:
1)
Eggs are collected from women's ovaries (donor).
2)
Egg nucleus is removed with a needle.
3)
Nucleus of a mature skin cell of the individual in need of an organ (recipient)
would be extracted.
4)
The nucleus of the recipient then would be introduced into the cytoplasm of the
donor enucleated egg.
5)
After the egg containing the patients DNA start to divide ESC would be
harvested.
6)
The ESC's then cultured, differentiated, and used to generate an organ or tissue
that is a genetic match to the recipient.
The clinical potential for stem cell products:
The
economic and psychological tolls of chronic, degenerative, and acute diseases in
the United States are enormous. It had been estimated that up to 128 million
people suffer from such diseases; thus, virtually every citizen is effected
directly or indirectly. The total cost of treating diabetes, for example is
approaching $100 billion in the United States alone. As more research takes
place, the developmental potential of different kinds of stem cells will become
better understood. As the science is understood now, adult stem cells are
limited in their potential to differentiate. Embryonic germ cells have a great
differentiation capacity, and embryonic stem cells are thought to be able to
differentiate into almost any tissue. Thus, different types of stem cells could
have different applications.
Some
examples of treatments for major disease. Type I diabetes in children, nervous
system disease (Parkinson's, Alzheimer's, etc), primary immunodeficiency,
diseases of bone, cartilage, and cancer.
In
August 2001, President Bush approved the use of federal funds to support
research on a limited number of existing ESC lines. Federal funding to a limited
number of cell lines will hamper the progress of science. Those opposed insist
that any use of cells derived from human embryo constitutes a significant break
of moral principles. Such arguments frequently ignore or mis-characterize the
scientific facts. Every day hundreds of fertilized eggs and or embryos not
being used in IVF program are destroyed instead of being used for research. We
all hope that the government pays more attention to this vital subject.
ICBH
Fatwa:
1.
IVF between husband and wife is Halal (Allowed).
2.
Stem Cell Research on Unused Fertilized Eggs are Halal.
Please let us know your comments.