First, a little biology happens. An egg cell carries one half of the genes from a female and a sperm cell does the same for the male. After an egg cell is successfully fertilized by a sperm cell, an individual is formed with a unique and complete set of genes. Although it now consists of a single cell, it will grow into an adult containing the many different cell types necessary to form the many different components of the body. The stepwise process of changing into varying cell types is called differentiation.
As cells go down the path of differentiating into tissues, they eventually reach a point of no return after which they lose their potential to develop into some other tissue; there is no going back. However, some of the original cells remain behind. They still have the ability to multiply and provide new cells that move forward into whatever cells the body needs. The cells that remain behind are called stem cells.
They are present in most parts of the adult body, but they are most easily separated from adipose tissue (i.e. fat), which is readily accessible via minimally invasive procedures. Therefore, it will be the tissue of choice for obtaining adult stem cells to be placed in The Stem Cell Zoo repository. However, if other sources present themselves for easy access we will certainly try to take advantage of them. For instance, if a live birth occurs in clean conditions (e.g. a Caesarian section), the umbilical cord would prove to be a very adequate source of stem cells from the newborn and abdominal fat could be taken from the mother during the surgery.
Embryonic stem cells arise from the first few divisions of a newly fertilized egg. They have not yet started down any particular path of differentiation and can, therefore, develop into any type of cell found in an adult. There has been a lot of controversy surrounding the use of embryonic stem cells in research or in clinical therapy.
Embryonic stem cells are designed to produce all of the tissues needed in an adult of the species. When administered to a recipient, they tend to form complex, aggressive tumors with multiple tissue types (teratomas). There is also a risk of rejection because they are not the patient’s own stem cells. To date, there are no clinical uses for embryonic stem cells. Furthermore, the harvesting of embryonic stem cells always results in the death of the donor embryo. That, of course, raises grave ethical concerns in endangered species and, in particular, humans. Embryonic stem cells will not be considered for use by The Stem Cell Zoo.
The stem cells isolated from our animal patients can be stored at liquid nitrogen temperatures for an indefinite period of time. They can be thawed and placed on tissue culture media to expand their population. Some of them can be used therapeutically or for research purposes and the remainder can be placed back into storage for future use. This process can be repeated many times.
Therapeutic doses of stem cells have been used in many species of animals, including humans, for a wide range of diseases. In veterinary medicine they have been used primarily in the treatment of joint, tendon, ligament and muscle injuries. It is hoped that many currently intractable diseases will be amenable to stem cell therapy. The list is long, but a few notable studies are treating kidney failure, nerve damage and diabetes with stem cells. This new branch of promoting healing is called regenerative medicine. We may even be close to re-growing lost digits or limbs!
Unfortunately, our endangered animals provide no financial incentive for drug companies to do research on their behalf. Their numbers are too few to result in a profitable product used to treat them. It will be up to organizations like The Stem Cell Zoo to promote research on the use of regenerative medicine in exotic species.
Research on stem cells has already resulted in the production of sperm cells. Recently, human ova were successfully produced from embryonic stem cells. It is very likely that in the near future scientists will be able to reliably produce both sperm and ova from adult stem cells. The implications of that are staggering.
If stem cells are available from a species that has become extinct, they could be used to provide the sperm and ova needed to do in vitro fertilization. The resultant embryos could be put into surrogate mothers from a similar species and the once extinct species could be brought back! The same process could be used to expand the population or range of existing species as well.
While other efforts are underway to preserve the DNA (using skin fibroblast cells) and germ cells (sperm and ova) of endangered species, The Stem Cell Zoo would be able to provide a renewable source of both DNA and germ cells (which are consumable and can’t replicate themselves).
Your tax-deductible donations to The Stem Cell Zoo will be used to pay for the isolation of stem cells from adipose tissue collected from zoo animals as part of their regularly scheduled preventive medicine program. The stem cells will be stored indefinitely at liquid nitrogen temperatures in partnership with an internationally recognized conservation research institute. Unfortunately, I am unable to provide their name until we have finished negotiating the terms of a partnership, but it is a trusted, stable organization.
When doses of stem cells are to be used for research purposes approvals must be granted by several oversight committees as well as the institution that is in stewardship of the donor animal. It is to be noted that the use of any tissues or stem cells derived from them is highly regulated. The Stem Cell Zoo will have NO ownership of the stem cells.
The institution that can't be named will be performing research using lab animals to differentiate stem cells into sperm and ova with the intent of using the knowledge gained to do the same for endangered species. The Stem Cell Zoo will fund this research.
A budget of $350,000 for the first year would allow The Stem Cell Zoo to fund the research as well as the collection and storage of stem cells from about ten exotic species. Positive results are anticipated for all species. Once we achieve that mark we will have amassed enough experience, contacts in the zoo community and credibility to greatly expand the project. A national or international program is envisioned. It is hoped that routine banking of stem cells will become a part of every Species Survival Plan in line with the Association of Zoos and Aquariums efforts to prevent extinctions. However, we need the help of some donors with deep pockets or many, many small donors. A couple of million dollars would set us on the right path for years to come!
A second and perhaps more ambitious phase of this project is data management. Since much of this science is breaking new ground it will become increasingly important to develop a platform for sharing information while at the same time protecting intellectual and physical property rights. Developing a participation agreement to enable everyone to play well together may be even more difficult than reversing extinctions. It will take time and effort to get it right. A very diverse group of professionals will be involved and humans can be a tricky species to work with!
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