Stem Cells and Umbilical Cords

Scientists have been aware of the existence of these stem cells for many years but have only recently realized the potential medical applications of the cells. More than a decade ago, scientists discovered that if the normal connections between the early cellular progeny of the fertilized egg were disrupted, the cells would fall apart into a single cell progeny that could be maintained in a culture. These dissociated cells, otherwise known as embryonic stem cell lines, continue to divide in culture, producing large numbers of cells at a fast pace. However, these early embryonic cells would lose the coordinated activity.

Scientists quickly discovered that these cells retain the ability to generate a great number of mature cell types in culture if they are provided with appropriate molecular signals (Reaves, 2001). Scientists have made significant progress in discovering these signals and are still working on it. While it is a difficult task, scientists are pursuing it with great excitement because it is widely believed that cultured embryonic stem calls can be induced to generate all the mature cell types in the body. These cells could possibly be used to replace damaged or sick cells in patients with injuries or degenerative diseases.

In the most controversial method, scientists can take the stem cells from aborted fetuses, first asking for signed consent from a patient who had previously decided to terminate her pregnancy. This is the procedure most often highlighted by pro-life activists who oppose supporting stem cell research.

However, there are other less-controversial methods in which stem cells can be utilized, such as umbilical cord blood stem cell use. Umbilical cord blood stem cells are the youngest safely available stem cells and are the product of live birth. Freezing these cells basically stops the clock and prevents aging and damage that may occur to the cells later in life. Another category of stem cells is adult stem cells, such as those found in bone marrow. Adult stem cells serve very specialized roles in children and adults and are not as proliferative as those found in cord blood. These types of stem cells are far less controversial than embryonic stem cells, and will be the focus of this paper.

Umbilical cord blood, in particular, offers great hope for the future of stem cell research and use. It has been approved for use by the FDA and other authorities since the late 1980's. The first umbilical cord blood transfusion cured a blood cancer in 1988. Over 1,000 cord blood transfusions, frequently used for children with leukemia, have been successfully performed in the United States with little side effects. Recent research has shown that umbilical cord blood stem cells have similar powers and health promoting benefits as do embryonic stem cells.

Advances are being made each day in providing greater safety to the patient. New methods of separating the stem cells from all other blood components have resulted in a product that consists of only stem cells. Since these umbilical cord stem cells have not developed ABO and HLA antigens on their surfaces, they do not induce graft vs. host reactions nor other problems that may occur with embryonic and adult bone marrow stem cells. Since the umbilical cord stem cells do not contain mature blood or tissue cells, foreign protein reactions are minimized. This paper will examine the potential of these types of stem cells, in an effort to demonstrate how stem cells from umbilical cord blood may help scientists solve the ethical debate and enhance humanity.

Background on Stem Cells

Stem cells are cells in the body that have the unique ability to regenerate and change shape (How Stuff Works, 2003). Unlike other types of cells, stem cells can change into other types of cells. Stem cells are at the center of an innovative field of science known as regenerative medicine. Because stem cells can become bone, muscle, cartilage and other specialized types of cells, scientists believe that they have the potential to treat a variety of diseases, including Parkinson's, Alzheimer's, diabetes and cancer. Eventually, stem cells may also be used to regenerate organs, eliminating the need for organ transplants and other surgeries.

Stem cells are like little kids who, when they grow up, can enter a variety of professions," says Dr. Marc Hedrick of the UCLA School of Medicine (How Studd Works, 2003). "A child might become a fireman, a doctor or a plumber, depending on the influences in their life -- or environment. In the same way, these stem cells can become many tissues by making certain changes in their environment."

Stem cells can be broken down into four basic types (How Stuff Works, 2003):

Embryonic stem cells - Stem cells found in human embryos

Fetal stem cells- Stem cells found in aborted fetal tissue

Umbilical stem cells - Stem cells found in umbilical cords

Adult stem cells - Stem cells found in adult tissue

Embryonic and fetal stem cells have the potential to change into a greater variety of cells than adult stem cells do. In April 2001, researchers at UCLA and the University of Pittsburgh found stem cells in fat sucked out of liposuction patients. Prior to this discovery, stem cells were found only in bone marrow, brain tissue and fetal tissue -- sources that have caused both logistical and ethical problems. Stem cells from fat have the ability to mature into other types of specific cells, including muscle, bone and cartilage, but how many other types is still unknown.

As stem cells research advances, scientists are discovering more and more about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. This promising area of science is giving scientists hope that cell-based therapies can be used to successfully treat disease.

Stem cells have two major characteristics that set them apart from other types of cells (National Institute of Health, 2002). First, stem cells are unspecialized cells that renew themselves for long periods through the process of cell division. The second is the fact that under certain physiologic or experimental conditions, stem cells can be induced to become cells with special functions such as the beating cells of the heart muscle or the insulin-producing cells of the pancreas.

Most of today's scientific research is performed using two types of stem cells from animals and humans: embryonic stem cells and adult stem cells, both of which have different functions and characteristics. More than two decades ago, scientists discovered ways to obtain or derive stem cells from early mouse embryos. After a detailed study of the biology of mouse stem cells, scientists discovered, in 1998, how to isolate stem cells from human embryos and grow these cells in laboratories. These cells are known as human embryonic stem cells. The embryos used in these studies were developed for infertility purposes through in vitro fertilization procedures. After they were no longer needed, they were donated for research with the donor's consent.

Stem cells are of great significance for living organisms today for a variety of reasons. In the three to five-day-old embryo, which is known as a blastocyst, a small group of approximately 30 cells known as the inner cell mass creates the hundreds of highly specialized cells that make up an adult organism. In the developing fetus, stem cells in developing tissues create the multiple specialized cell types that make up the heart, lung, skin, and other tissues. In some adult tissues, such as bone marrow, muscle, and brain, discrete populations of adult stem cells generate replacements for cells that are destroyed by age, injury, or disease.

Stem cells are different from all other kinds of cells in the body. All stem cells -- regardless of their source -- have three general properties (National Institute of Health, 2002):

They are capable of dividing and renewing themselves for long periods;

They are unspecialized; and They can give rise to specialized cell types.

Because a stem cell does not have any tissue-specific structures enables it to perform specialized functions. (National Institute of Healt, 2002). A stem cell cannot work with its neighbors to pump blood through the body (like a heart muscle cell can); it cannot carry molecules of oxygen through the bloodstream (like a red blood cell can); and it cannot fire electrochemical signals to other cells that allow the body to move or speak (like a nerve cell can). However, unspecialized stem cells can create specialized cells, including heart muscle cells, blood cells, or nerve cells.

Unlike muscle cells, blood cells, or nerve cells -- which cannot replicate themselves -- stem cells can replicate many times. When cells replicate themselves many times it is known as proliferation. A starting population of stem cells that proliferates for many months in the laboratory can create millions of cells. If the resulting cells continue to be unspecialized, like the parent stem cells, the cells may be capable of long-term self-renewal.

Scientists believe that stem cells may be effective in treating diseases such as Parkinson's disease, diabetes, and heart disease. Scientists want to study stem cells in the laboratory in an effort to learn about their important properties and what differentiates them from specialized cell types. As scientists discover more about stem cells, it may become possible to use the cells not just in cell-based therapies, but also for screening new drugs and toxins and understanding birth defects. However, human embryonic stem cells have only been studied for only a few years. Thus, in order to develop these types of treatments, scientists are studying the fundamental properties of stem cells, which include (National Institute of Health, 2002):

Determining precisely how stem cells remain unspecialized and self renewing for many years; and Identifying the signals that cause stem cells to become specialized cells.

Scientists today are attempting to understand two fundamental properties of stem cells that relate to their long-term self-renewal (National Institute of Health, 2002):

Why can embryonic stem cells proliferate for a year or more in the laboratory without differentiating, but most adult stem cells cannot; and What are the factors in living organisms that normally regulate stem cell proliferation and self-renewal?

For researchers, answering these questions may be the key to understanding how cell proliferation is regulated during normal embryonic development or during the abnormal cell division that leads to cancer. This information could help scientists grow embryonic and adult stem cells more efficiently in the laboratory.

About Umbilical Cord Stem Cells

Umbilical cord stem cells, which are taken from newborn babies, are the same hematopoietic, or blood-forming, cells found in bone marrow and in the circulation, although their quantities in the blood are relatively scarce (Barker, 2002). Stem cells can regenerate the body's ability to produce the erythrocytes, platelets, and leukocytes it needs.

Umbilical cord blood stem cells are referable to those found in bone marrow for the following reasons:

Higher chance of match: Cord blood can be successfully used even when a perfect match does not exist. Siblings have up to a 50% chance to find a cord blood match, compared to bone marrow.

Immediate availability: Families who bank cord blood can be assured that the stem cells are available if needed in the future. It is commonly known that trying to find a bone marrow match can be a much more time consuming process, even between family members. Early treatment can minimize disease progression.

Less GVHD: Patients who receive cord blood transplants from their families have significantly fewer problems with Graft vs. Host Disease, a fatal complication associated with transplants.

Various stem cells are obtained differently according to their source (Wolf, 2002). From bone marrow, stem cells are obtained in the hospital under anesthesia: the donor stores units of blood in advance to be infused during and after the procedure, and has insertions of a large bore needle into the hip bones for removal of marrow. Stem cells are obtained from peripheral blood by a process called apheresis or leukapheresis. Blood is drawn from peripheral blood through an IV and flows into a leukapheresis machine. The stem cells are collected by centrifugation and removed, and the blood is returned to the patient in one continuous process. The harvest of umbilical cord blood involves syringes or small infusion bags to remove blood from the cord after it is clamped and cut. Ideally, the process is initiated shortly after the birth while waiting for the placenta to be delivered, though it can be delayed for up to 10 minutes so that the blood can be collected after expulsion of the placenta.

Cord blood stem cells have been used as successfully as bone marrow to treat many conditions, including leukemia, anemia, and lymphoma, and may also be useful in gene therapy (Wolf, 2002). Cord blood stem cells have an advantage because they are less likely to cause problems with similarly matched specimens than bone marrow. The immune cells present in cord blood seem to have immunologic immaturity. In addition, fewer viruses are present in umbilical cord blood stem cells than in bone marrow. Umbilical cord blood also seems to require less stringent matching for unrelated donors.

In addition, the cord blood is a perfect match for the infant from whom it is collected. Siblings have up to a 50% chance of being a suitable match for future transplantation in another sibling in need. Parents may be matches as well. Some adoptive parents have worked with their social service agency to obtain the birth mother's permission to collect the umbilical cord blood so they will have a source of genetic material available for their adopted baby.

Since the first cord blood stem cell transplant in 1988, more than 2000 transplants have been performed (Wolf, 2002). Research is being conducted at medical centers worldwide and the National Institutes of Health has a number of working groups and conferences revolving around stem cell research. While much debate revolves around the use of embryonic stem cell lines for research, the collection of cord blood stem cells is simply a matter of recycling medical waste.

According to research, more than 125,000 units of cord blood have been stored worldwide (Wolf, 2002). In the past few years alone, research has demonstrated that cord blood stem cells can differentiate into other types of cells in the body. The regenerative qualities of stem cells have been brought to the forefront in the field of cellular repair. Stem cells have been labeled an important biological resource and researchers are conducting more and more studies to unlock the potential of umbilical cord blood stem cells in future applications for diseases like Alzheimer's, diabetes, heart and liver disease, muscular dystrophy, Parkinson's disease, spinal cord injury, and stroke.

The ability to store cord blood stem cells for a family's potential need may be particularly significant for those with a family history of leukemia or cancer. Long waits for a bone marrow donor search often means that the patient becomes more ill. If an extensive system of cord blood is available, the waiting time for a search could be greatly reduced, because cord blood requires less stringent matching. In time, greater amounts of cord blood will be saved, as the list of potential benefits increases.

Still, while this type of research is not as controversial as embryonic stem cell research, the collection and storage of cord blood are not without controversy (Wolf, 2002). Placentas and umbilical cords were once casually discarded. Now that their biologic potential has been confirmed, many companies are marketing cord blood's potential benefits to expectant parents. The odds of needing a given sample of cord blood by the family saving it are unknown, though for some families, the expense of saving it is worth it.

Estimations regarding the need for a given cord blood sample vary. One estimate of a child needing his or her own cord blood stem cells is 1:10,000 (Wolf, 2002). Another places the odds at 1:1000 to 1:2000. The probability of use varies depending on individual circumstances. Disturbing statistics reveal that every year there are about 8,000 new cases of cancer in children under the age of 15. These children could potentially benefit from the use of cord blood stem cells, so perhaps expectant parents should make the effort to donate their newborn's cord blood or store it for their own family's potential use.

According to Cryo-Care, a provider for the safe storage of stem cells taken from the umbilical cord blood, there are many steps that doctors must follow when collecting and storing these cells. In a sterile environment, preferably the delivery table, and immediately following the delivery, doctors collect the umbilical cord blood by following these steps:

1. Placing two clamps on the umbilical cord as close as possible to the baby's abdomen.

2. Cutting the umbilical cord between the two clamps and removing the baby from the sterile environment.

3. Taking the sterile blood bag out of its packaging and placing it nearby in preparation for the cord blood collection.

4. Disinfecting the umbilical cord where the needle will be inserted by means of the alcohol tissues or the supplied disinfectant kit.

5. Pricking the umbilical cord in the disinfected area with the needle attached to the blood collection bag.

6. Holding the bag below the level of the cord to allow the blood to drain freely.

7. Filling the bag to capacity if possible (it can contain 250ml, or approximately - 300gr). A minimum of 60ml of blood must be collected in the bag.

8. When as much blood as possible has been taken, gently squeezing any remaining blood from the tube into the bag.

9. At least two security knots should be tied in the collection tube to prevent leakage during transportation.

10. Cutting the needle from the bag and disposing of it appropriately in accordance with the hospital's waste disposal regulations.

11. Turning the bag over slowly several times, to mix the cord blood with the CPD anticoagulant.

12. The collected cord blood must be kept at room temperature; it should not be placed in a refrigerator or freezer.

Once the blood is collected by the cord blood bank, the red blood cells are removed from the cord blood, which is frozen in long-term cryogenic storage. Reputable banks remove the red blood cells so that the risk of blood type (ABO) compatibility is minimized. This means that if the stem cells are later needed for a family member other than the newborn, there is a greater chance of a match.

The Great Stem Cell Debate

Stem cell research is a hot topic for media headlines and has become one of the most controversial subjects in America today. For pro-life advocates, the moral costs of stem cell research far outweigh any potential benefits. For scientists, the possibilities of research are incredible and bewildering (Reaves, 2001). Neither party denies the moral dilemma of the stem cell debate. However, researchers say, to turn back now would be like turning our backs on a bright, sustaining light because we are terrified of the shadows it creates.

Scientists have revealed that stem cells could possibly hold the key to discovering a cure for several mysterious diseases, including Parkinson's and Alzheimer's. However, moral issues concern the public, despite the obvious positive consequences. The core of the stem cell debate is a battle over abortion, as stem cells come from embryos.

As far as public opinion is concerned, pro-life advocates compare the use of stem cells for research to experiments performed by Nazi doctors during World War II (Condic, 2002). According to pro-stem life research advocates, they are focusing in on a narrow subject and ignoring the possibilities of stem cells in scientific research. These cells could truly benefit millions of ailing patients and their families. In addition, they argue, these cells would otherwise be useless and unceremoniously discarded.

The issue of stem cell research first arrived on the scientific scene in 1998 when researchers first reported the isolation of human embryonic stem cells (Reese, 2001). The discovery, which was made by Dr. James Thomson, a biologist at the University of Wisconsin, offered great promise for new ways of treating various diseases. Stem cells, it was found, which are derived from embryos, can theoretically differentiate into virtually any type of human cell, from blood cells to skin cells.

Stem cells are basically any type of cell that is able to divide and generate two progeny (daughter cells). Of the progeny, one is destined to become something new and the other replaces the original stem cell. At different stages of development, there are many stem cell populations. For instance, the brain's cells arise from a neural stem cell population in which each cell produces one brain cell and another copy of itself every time it divides. The earliest stem cells are the embryonic stem cells and they give rise to all tissues in the body. This means that they are capable of generating all things.

Embryonic stem cells are considered the most useful in research because they can become any type of cell, while adult stem cells are more limited. There is no controversy revolving around the use of human adult stem cells in research, since they can be retrieved from the individual requiring the therapy. Since ES cells derive from the inner cell mass of the early embryo, they are capable of forming all the tissues of the body. But there is much controversy over the use of embryonic stem cells.