Stem Cells - The Science and the Controversy

Here's an introductory video on stem cells and how they work:

The Basics - Science

            Stem cells can be found in a variety of places.  They can be found in bone marrow, heart muscle, adipose tissue (fat) and embryonic blastocysts.

           

         Stem cells are found in two types, totipotent, and pluripotent.  Pluripotent stem cells can form into any cell that they are introduced to.  They can also make more stem cells.  Totipotent stem cells can only form into the cell that they are from.  For example, a totipotent stem cell from the bone marrow can only form into a bone marrow cell.  The same follows with heart cells; a totipotent stem cell from the heart can only into a heart cell.

           There is another type of stem cells called induced pluripotent stem cells.  This is when scientists make a cell forget what it was and relapse into the form of a stem cell.  Induced pluripotent stem cells are not permanent.  They can only be pluripotent stem cells for a certain amount of time before they go back to whatever cell they were before. 

          Stem cells can be used for organ transplants by simply injecting a sample of stem cells into the affected area.  The stem cells from into the cell that they were injected into.  The same process can be used for diseases. Recently, scientists have been using stem cells to cure diseases that lead to blindness. Another example is someone who regrew their finger. 

          For patients who need to be treated of a disease using stem cells, scientists are needed to carry out a process of adding new healthy cells to the damaged organ or tissue. For example, a patient who has a damaged heart would need scientists to inject stem cells into the damaged area and send signals to these cells so that they can become healthy heart cells. At this point, the cells can grow and consequently repair the damaged tissue. Although not yet used on a human patient, this treatment has been tested on mice with damaged hearts. This tests showed that after the treatment the mice showed improvement in heat function and blood flow. Ideally, humans will eventually be getting these extravagant treatments on their own organs or damaged tissue. The idea would be that anytime one has a dysfunctional organ, it can easily be replaced or repaired with the help of stem cells and the demand for organ donors wouldn't need to be high because of a new breakthrough in disease treatment. 

The History

     Stem Cell's history can be traced all the way back to 1868. This is the first time the term stem cell was used in scientific literature. He used it to describe a fertilized egg becoming an organism and the ancestor cell of all cells.

      Then in June of 1909, Alexander Maximow lectures in Berlin about his theory that all blood cells come from the same ancestor cell. This leads people to believe that the cells are multipotent and can become other cells.

     In the 1950's, more discoveries were made by Leroy Stevens. Leroy Stevens found tumors in mice that he was using in his experiments in 1953. These large tumors contained mixtures of undifferentiated and differentiated cells. These cells were a variety of blood, hair, intestinal, and bone cells. Four years later, E. Donnall Thomas completed the first human bone marrow transplant.

     A major discovery in Stem Cell research was made on Feb 2, 1963. This is when Canadian scientists Ernest McCulloch and James till discover the first evidence for blood stem cells whilst preforming experiments on bone marrow in mice. Five years later in 1968, Robert A. Good preformed the first ever bone marrow transplant in a child suffering from an immune deficiency that was the cause of death for other members of his family. He used bone marrow from his sister for the procedure.

     Then in 1981, the first ever embryonic stem cells are isolated by deriving pluripotent cells from the embryos of mice, the procedure was completed by Martin Evans and Gail Martin. In December of 1986, Andrew Lassar and Harold Weintraub convert rodent fibroblasts into myoblasts using MyoD. This is an


important breakthrough in regenerative medicine. Fibroblasts are a connective tissue and myoblasts are generative muscle cells. In 89' scientists Mario Capecchi, Martin Evans, and Oliver Smithies combined their research and created "knockout mice". These mice were made out of stem cells. Since their creation there have been over 500 mouse models of human disease.

     In 1997, Dominique Bonnet and John Dick discover that leukemia cells come from the same stem cells as our blood cells. A year later, the first human embryonic stem cells were created. These cells are a huge breakthrough for drug discovery and transplantation medicine. This is because the cells are pluripotent.

   Then in 2001, George Bush authorized the research of stem cell lines, however scientists think that these lines may be outdated. In 2002 a research team combines gene and stem cell therapy to treat a mouse model of immune deficiency. One year later, George Q. Daley and his team publish findings on converting stem cells from mice into germ cells and primitive sperm cells capable of fertilization. These germ cells have given scientists the opportunity to study cancer growth, the development of sperm cells, and other cell processes. On May 19, 2005, scientists in South Korea announce that they have used therapeutic cloning to create 11 stem cell lines matching their donors. This is huge news to scientists because patients receiving their own stem cells are unlikely to reject the transplant. However, it is later revealed that the results were falsified and lines were created using other methods. Seven months later Yuan Wang, George Q. Daley, and other researchers publish findings that greatly improved the process of converting a mouse's embryonic stem cells into blood stem cells for transplantation. Then in 2006, scientist Shinya Yamanaka and Kazutoshi Takahashi announce that they have created induced pluripotent cells from rodents. The iPS cells are adult cells that have been reprogrammed to look and work like embryonic stem cells. This is another huge discovery due to their value as a resource for stem cell research and eventual cellular therapeutics. George Q. Daley made embryonic stem cells through parthenogenesis that same year. In 2007 the first iPS cells in humans were created. In 2008 ten disease specific stem cell lines were created. In 09' safer ways to gather human iPS cells were created and a variety of trials and regulations were established.

The Controversy:

The Case For Why Embryonic Stem Cells Shouldn't Be Used:

           Many religious leaders believe that scientists should use a more ethical approach to stem cell research like focusing on research involving adult stem cells instead of embryonic stem cells.  The reason that the question regarding the ethics involved with stem cell research exists is because many people believe that by taking stem cells from embryos we are using "the next generation as mere raw material for satisfying the needs of our own." A spokesperson from the United States Conference of Catholic Bishops released a statement about their view on stem cells stating that  "Embryonic stem cells have not helped a single human patient or demonstrated any therapeutic benefit.  By contrast, adult stem cells and other ethically acceptable alternatives have already helped hundreds of thousands of patients, and new clinical uses expand almost weekly." Once again, adult stem cells are mentioned as the most reasonable alternative that is both ethical and ground-breaking in terms of stem cell use and research. 

           Scientists have been eagerly looking into the use of adult stem cells instead of embryonic stem cells.  In fact, many scientists believe that it might be possible to "reprogram" adult stem cells back to an embryonic cell like state.  If achieved, adult stem cells could provide a source for replacement tissue with breaking any morals or raising ethical questions.  Another benefit of using this technique would be that the cells would come from the patient's own body and less likely be rejected.  Additionally, embryonic stem cells have been known to cause more side effects when treated on patients while adult stem cells on the other hand don't pose a likely hood of major side effects. 

The Case For Why Embryonic Stem Cells Should Be Used:

           Although not as controversial as embryonic stem cells, adult stem cells are difficult to isolate from the surrounding tissue.  Embryonic stem cells also multiply and regenerate much faster that adult stem cells.  Adult stem cells haven’t been proven to easily differentiate into different tissue types while embryonic stem cells are noted to uniquely be able to efficiently transform into other tissue types.  Although scientists have looked into the possibility of reverting adult stem cells back into an embryonic state, these treated cells have been known to have the tendency to turn into cancer cells.  These extremely risky side effects render them too dangerous for use in the human body like for transplants.  Embryonic stem cells show a way more promising future and are proving to be way more practical than adult stem cells.

           Karen Miner, a victim of paralyzation from the shoulders down created an organization that advocates stem cell research in California.  The organization is called "Californians for Cure".  Despite many “pro-life” organizations being against Miner and the cause she is supporting, Karen continues to stay strong.  Miner explained, "They really don't understand that it's not destroying a life, it's saving a life, I do not believe these cells are children.  Blood cells are alive, and so are skin cells.  We cut into them during surgery, but no one considers that murder.  They make it sound like there are people growing out in warehouses that we take body parts from."