Stem Cell Facts - Embryonic Adult Placental Cord

In Vitro Fertilization Cloning Nuclear Transfer Research Principles

Mar 11, 2009 Donald Reinhardt

On 3/9/2009 President Obama of the USA issued a Presidential Order that permits federal funding for studies of embryonic stem cells. What is the meaning and significance?

All humans start life as one diploid cell, a zygote, formed by the union of one sperm and one egg and their DNA-rich nuclei. Zygotes and all other diploid cells contain a double-dose of genes: one set of genes from each parent. In humans, the diploid number is 46 chromosomes. Chromosomes are DNA threads. Chromosomes are linked genes with some protein. We have about 30,000 genes.

Mitosis Embryos Stem Cells Tissues Organs

Mitosis is a cell process that increases the DNA of a growing cell to double diploid (92 chromosomes) and then halves this DNA as the dividing cell forms two offspring cells. A one-celled zygote goes from 1 to 2 to 4 to 8 to 16 cells quickly, a lovely sphere or ball of cells. As the cell mass grows, some cells assume new roles and differentiate into specialized masses of cells tissues: skin, blood, muscle, bone, nerve. The tissues then become organized into organs and organ systems such as the entire skin, intestines, lungs, heart, spleen, kidneys, skeleton and brain and spinal cord.

Stem cells are those basic cells, that when prompted, can generate important, specialized cells.

Stem cells are called pluripotent cells because they can produce specialized cells.

Types of Stem Cells: Embryonic, Adults, Cord and Placental

Stem cells are found in embryos, adults, placentas, umbilical cords. Many stem cells can be grown separately from the person in vitro. In vitro growth is tissue culturing and occurs in a controlled lab setting. In vitro tissue cultured cells grow in glass test tubes or plates. Scientists can watch them, manipulate them and control them to behave in certain ways.

Embryonic stem cells are collected or harvested from very young embryos. Cord blood and placental stem cells come from pregnant women post delivery or abortion. Adult stem cells are derived from adults.

In summary, there are several types of stem cells. Embryonic stem cells can be grown most readily in tissue culture and they have unique abilties to generate tissue and organ cells that can be implanted into other people.

In vitro Embryonic Procedures: Fertilzation, Nucleus Transfers, Cloning

Fertilization in glass containers was the first important use of in vitro techniques. First, an egg is removed from a female donor. Next, sperm are added to the plate and soon, after fertilization, the egg is reinserted back into the woman's body. This was the beginning of "test tube" babies and artificial conception. Dr. Patrick Steptoe performed the first successful reproductive in vitro event that enabled a woman who had difficulty getting pregnant to now have a baby.

Doctors and scientists also determined that cloning of animals would be possible. "Dolly" was a sheep who had all of her mother ewe's genes. Dolly was a "younger, identical twin" of her mother - no father of Dolly was used. Instead, a diploid cell nucleus from the mother ewe was inserted into an enucleated egg. That egg was implanted in an ewe's uterus and allowed to develop into an embryo and be born as a baby lamb: Dolly.

Cloning, therefore, involves taking the egg, removing its nucleus (enucleation), and inserting a diploid nucleus from another cell of the same individual, or a different individual. The egg is regulated now not by the nucleus it had, but by the nucleus that was inserted. Theoretically, any human could be cloned; if a human egg nucleus is removed, a diploid nucleus of that person is inserted and the embryo develops to term. This type of cloned embryo is ideal for tissue transplants because the cells are the same as the human donor.

A clear series of figures and diagrams is shown by clicking here at this embedded site.

The promise of stem cells and research is to produce cells and tissues that can replace and reconstitute damaged or diseased human tissues. These tissues could be planted or transplanted into the patient or recipient and there might be, under the right conditions, a regeneration of organs such as heart, liver, pancreas, spinal cord and muscles. There is nothing wrong with this approach when adult, placental or umbilical cord stem cells are used in tissue cultures; these were never destined to become a person. However, when diploid eggs are used and embryos are created and developed in the lab, new issues arise. Reproductive cloning and therapeutic cloning are both realities.

Theoretically, any fertilized egg has the potential to become a full born person. This is the issue that has entered into the science of stem cells and embryos. If the cloned egg is placed in the uterus, it can develop into that cloned human or animal. If a cloned egg is placed in a tissue plate it will grow as far as science and technology can carry it. Could an embryo be carried to full term in a sterile, nutrient vessel that mimiced the uterus? We do not know. It is possible.

Cures are desired for all diseases; that is the nature of the goodness of humans and their endeavors. Cures that require the sacrifice of one "life" for another's life is the debate at hand.

Summary and Concluding Ideas

The stem cell story is exciting and controversial.
It will require the best minds and the greatest care to do stem cell technology well.
The development of a cloned baby for the sole purpose of the removal of tissue or organs from that baby to save the original donor of that nucleus means that the lab baby would be destroyed for its tissue.
One life, started in a lab tissue culture, would be sacrificed for another, who is already born.

Stem cells and embryonic cloning are important issues that penetrate the very core of humans and science in the quest for better health for all. There is much left to discover and tell in this story.

Resource and References

Alters, S. and B. Alters. 2006. Biology. Understanding Life. John Wiley & Sons, Inc. 755pp

The copyright of the article Stem Cell Facts - Embryonic Adult Placental Cord in General Medicine is owned by Donald Reinhardt. Permission to republish Stem Cell Facts - Embryonic Adult Placental Cord in print or online must be granted by the author in writing.