Disease and illness are tough matters of life that must be dealt with in order to extend the quality and longevity of human life. Many illnesses and diseases hamper the ability of some to live a long and healthy life, but some of these problems are still yet to be solved by modern medicine. Although humanity has come a very long way with medical science, diseases such as Parkinson's, heart disease and many others still claim many people each year, without the chance of recovery, but only with the chance of slowing down the progression of the disease. A new form of research and medicine is needed in order to more deeply understand and cure such diseases and scientists think that they found a great way of not only understanding how diseases work in the cellular level, but also, find a way to cure them. Stem cell research has the ability to enable scientists to see how such rampant and killer diseases develop in cells of the body by testing on stem cells and the ability to use those stem cells in regenerative medicine. In recent history many countries, including our own, have tried to place limits and get rid of stem cell research because of the ethical problem that it faces. Because of the use of embryonic stem cells, many people believe that the science should not be allowed and that using the embryos is unethical and wrong. But, stem cell research is not only a great way of finding cures, but also making cures and should be practiced for the greater good of humanity. 

Stem cell research has its beginnings very long ago in about 1868 where the term "stem cell" was first "used by a German biologist Ernest Haeckel to describe the fertilized egg that becomes an organism, and also to describe the single-celled organism that acted as the ancestor cell in all living things in history." (Boston Children Hospital) In more modern times, stem cells were observed in mice. In 1953 Leroy Stevens performed cancer research on mice and found that the tumors had contained cells that were of many different varieties and concluded that the cells were pluripotent, meaning that they can transform into any cell type in an animal. Thirty years later in 1981, Martin Evans and Gail Martin conduct separate studies to isolate embryonic stem cells for the first time ever by deriving pluripotent stem cells from the embryos of mice. Being able to separate the stem cells in an embryo from a mouse is a major step in the history of stem cell research, without this step scientists wouldn't have been able to do the same for human embryonic stem cells. In 1986, two scientists using adult stem cells changed one muscle tissue into another by adding a single gene to the tissue, through this experiment they converted a type of connective muscle tissue directly into a regenerative muscle tissue. This previous year is the birth of regenerative medicine using adult stem cells. Lastly, one more year important in stem cell research is in 1998 where a team at University of Wisconsin, Madison go and takes the principle of the experiment that was mentioned earlier using mice, and instead separate human embryonic stem cells and discover their pluripotency opening up the opportunity for using stem cells in drug discovery and other medicines. The historical foundation of the research is important to set up to greater understand how the science has come along and evolved from what it was to what it is today.

There are many things to answer about stem cells, the different types, what they're used for and why they're important to furthering medicine. Stem cells are simple cells in the body that have no specialization that can develop into differentiated cells (cells of a specific variety). Stem cells, in general, have a trait of regeneration and the capacity to become any type of cell that is necessary. Stem cells are also distinguished from other cell types by two characteristics, their use of cell division and their experimental uses.

Stem cells are made through a process that involves many different steps, and the process depends mainly on In vitro fertilization clinics in order for the researchers to have a way of getting stem cells. In vitro fertilization is a process where mature eggs from a woman's ovaries are collected and fertilized by sperm in a lab. This process of In vitro fertilization creates many embryos for which the woman struggling with fertility then have implanted into her uterus in hopes that a pregnancy begins. This method of fertility assistance creates many embryos that can be either saved for future use through freezing, or given up to the clinic for donation. If the embryos are no longer needed or wanted, the embryos are taken by the clinic and donated from the clinic to the stem cell research facilities in order to be turned into stem cells. Without the IVF clinics donating left over embryos, the only other two options for making stem cells are by creating them solely for the purpose of destruction for research, or therapeutic cloning. "Therapeutic cloning is a term used to describe the creation of an embryonic stem cell line by a technique called somatic cell nuclear transfer (SCNT)" (Eurostemcell.org). In SCNT, an unfertilized egg is used along with the nucleus of a cell from an animal. By removing the nucleus in the egg and then adding the nucleus of the cell, this creates an embryo that is then allowed to grow into a blastocyst (the blastocyst is the second step in an embryo's development) which can then be broken down and stem cells can be collected from them. 

There are three different kinds of stem cells that exist today: Embryonic stem cells (stem cells that are derived from embryos), Adult stem cells (stem cells that are derived from already differentiated tissues), and induced pluripotent stem cells (iPSCs). Adult stem cells occur naturally throughout the body and in many different places like the brain and the heart most significantly. Adult stem cells are thought to reside in a specific area of each tissue called a stem cell niche (Stemcells.nih.gov). It is these adult stem cells that exist in each of our bodies today that allow our cells to replace themselves in certain tissues that need maintenance, because of injury or disease. Just what makes these adult stem cells useful for therapeutic reasons is because they occur naturally in our bodies and can be collected in order to produce regenerative medicine. Using adult stem cells, for example, from a specific organ, could then help to save someone who has suffered serious organ damage. Because of the way that adult stem cells work in our body, the extracted stem cells could then be used to repair said organ and aide it in regenerating. 

Scientists are now able to take adult stem cells and reprogram them into being more like embryonic stem cells through the introduction of embryonic genes (stemcells.nih.gov). These newly programmed stem cells are called induced pluripotent stem cells (iPSCs). Because of this ability to reprogram adult stem cells, it has made adult stem cells even more useful than they are in their original state. If the adult stem cells are to stay in their original state they can only be used on certain types of tissues for regenerative purposes. Through genetically reprogramming them they can turn back to the state at which they can become any tissue that is needed which makes for another viable source for pluripotent stem cells. There are problems that this technique faces though. The virus that is used in order to introduce the reprogramming is found to sometimes cause cancer. Until a completely guaranteed safe way of reprogramming the cells is found, unfortunately, this way of reprogramming is not viable for use in creating human regenerative medicine, but the promise of the idea is still great. Induced pluripotent stem cells also have the unique advantage of being derived from the donor's own cells. Because they're derived from the donor's cells they can then be used in the donor with very little chance of rejection by the immune system, almost like the rejection of an organ in a transplant. The theory is that scientists could take adult stem cells from a part of the body that does not need help, induce them to become pluripotent cells and then differentiate the now pluripotent cells to become the tissue that needs regeneration for use in medicine. 

Embryonic Stem cells are stem cells derived directly from human embryos. The embryos are allowed to grow into blastocysts and are then destroyed for the stem cells that are inside of them. These stem cells that are contained inside the blastocysts are all already pluripotent and have the ability to become any kind of cell tissue, because those stem cells would, if the embryo continued to grow, eventually begin to form into the beginnings of human tissues. Embryonic stem cells are so valued for their pluripotency and are envisioned to be used in regenerative medicine just like adult stem cells, but with much greater capability. Because it is not known all of the parts of the body that make adult stem cells, the already pluripotent embryonic stem cells could then be used in those areas where adult stem cells are not present. 

The process of differentiating the stem cells to turn into the specifically needed cells has been determined by a formula that has been worked on by scientists for years (stemcells.nih.gov). Any sort of factor changing the environment culture is in, to genetic changes of the cells can be used to differentiate the cells. If differentiation goes smoothly then the differentiated cells can then be used for therapeutic reasons in the future when we know how to apply them into medicine. 

Because of stem cell's ability to be induced into different types of tissue, this is useful in testing different types of medicines. By inducing stem cells into different types of tissues, scientists can use the newly formed tissues to then inject them with whatever disease they're trying to make medicine for or whatever disease they're trying to study. The reason stem cells are so useful for examination is because scientists can observe them under the microscope and observe how the disease develops from a cellular level. This observation allows for better medicine testing as it allows scientists to see how the disease effects each cell, rather than only being able to look at the physical effects that a disease has on a person. 

One disease that could become a major issue solved by the science of stem cell research is any sort of heart disease. "Heart failure is the leading cause of death worldwide and current therapies only delay progression of the disease. Laboratory experiments and recent clinical trials suggest that cell based therapies can improve cardiac function" (Segers). Over time your heart becomes less functional and its maintenance upkeep on itself can wear down to very little if anything at all. Because of this, diseases like Ischemic heart disease and issues like heart attacks which cause the death of the muscles in the heart become very detrimental to the health of the organ that determines your vitality. Stem cell research could have the answer to these conditions through regenerative medicine, but it's not as simple as just getting some stem cells for the heart. Because the human heart has very little capability for healing itself, there is issue with which kinds of cells to use for the regenerative medicine and the delivery of the medicines. Scientists do not yet understand well enough what kinds of cells assist heart tissue and therefore much more research needs to be done in deciding where the cells for the medicine comes from. This process could take even longer than initially thought out, because "different cardiac pathologies  --  for example, acute myocardial infraction (heart attack) and chronic ischemic cardiomyopathy  --  might require different types of stem cells or progenitor cell" (Seger). What this means is that different cells may be needed in order to help the heart based on whether it has suffered a heart attack or suffers from Ischemic cardiomyopathy (a disease in which "the hearts ability to pump blood is decreased because the heart's main pumping chamber, the left ventricle, is enlarged, dialated, and weak. This is caused by ischemia  --  a lack of blood supply to the heart muscle caused by coronary artery disease and heart attacks" (Cleveland Clinic).  

 Stem cell's ability to divide gives them the regenerative promise that is the real exciting part of the research. Because of their ability to divide and regenerate combined with their ability to be induced into any form of tissue, these newly formed tissues from stem cells can be used to regenerate parts of the body such as, many organs, gut and bone marrow, and even things such as limbs in the future. As recent as 2015, researchers have grown mice limbs, regrown damaged livers in mice, and have even grown human kidneys. As long as this exciting technology continues to develop, we could soon be at a state where organs could be grown specifically for people to have transplanted. This would make an immediate impact on the organ donation system and would potentially lessen the wait for organ donation for those that could afford to have their own substitute made. 

Stem cell research has come a long way from when the term "stem cell" was first derived in a scientific meaning. The research and technology that is developing and evolving even today can greatly impact the quality of life on earth for human beings through regenerative medicine being researched using stem cells, the use of stem cells to conduct experiments and test medicine, and the soon possibility to grow fully functional limbs and organs from stem cells. There are many challenges ahead still facing this science such as limited funding of research, the controversy behind the science, and the use of embryonic stem cells. Although stem cell research is facing all these problems it would do humanity a great deal of good to continue this research in order to further medical science and effect the world in a positive way.  

