Stem Cell Research Genetic Engineering,

Stem Cell Research

Genetic engineering, genetic modification, and gene splicing are terms used for the process of manipulating genes in an organism, generally outside the organism's normal reproductive process (Genetic pp). This usually involves the isolation, manipulation and reintroduction of DNA into model organisms, most often to express a protein, in order to introduce new characteristics to an organism that will increase its usefulness, such as increasing the crop yield of a species, introducing a novel characteristic or producing a new protein or enzyme (Genetic pp). Examples are the production of human insulin through the use of modified bacteria and the production of new types of experimental mice such as the "OncoMouse," cancer mouse, for research, through genetic redesign (Genetic pp). One of the most well-known application of genetic engineering is the creation of genetically modified organisms (Genetic pp). There are potentially profound biotechnology application of genetic modification, such as oral vaccines that are produced naturally in fruit at very low cost (Genetic pp).

Genetic engineering has become the gold standard in protein research, and major research process has been made using a wide variety of techniques, including loss of function, such as in knockout experiment, in which an organism is engineered to lack one or more genes (Genetic pp). Such an experiment involves creation and manipulation of a DNA construct in vitro, which consists of a copy of the desired gene which has been altered to cripple its function (Genetic pp). Then the construct is taken up by embryonic stem cells where the copy of the gene replaces the organism's own gene (Genetic pp).

Stem cells have the remarkable potential to develop into numerous different cell types within the body serving as a repair system in which they can theoretically divide without limit to replenish other cells as long as the person or animal is still alive (Stem pp). Whenever a stem cell divides, each new cell has the potential to either remain a stem cell or become another type of cell with a more specialized function, such as a red blood cell, brain cell, or muscle cell (Stem pp). Stem cell research continues to learn how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms, leading scientists to investigate the possibility of cell-based therapies to treat disease, a field referred to as regenerative or reparative medicine (Stem pp).

Stem cells contain two important characteristics that distinguish them from other types of cells:

First, they are unspecialized cells that renew themselves for long periods through cell division.

The second is that under certain physiologic or experimental conditions, they 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 (Stem pp).

Primarily, scientists work with two types of stem cells from animals and humans, embryonic stem cells and adult stem cells (Stem pp).

More than two decades ago, scientists discovered ways to obtain or derive stem cells from early mouse embryos, resulting in how to isolate stem cells from human embryos and grow the cells in the laboratory in 1998 (Stem pp). These are called human embryonic stem cells, which are embryos created for infertility purposes through in vitro fertilization procedures and when no longer needed were donated for research with the informed consent of the donor (Stem pp).

In the three to five-day-old embryo, called a blastocyst, stem cells in developing tissues give rise to the multiple specialized cells types that make up the lung, skin, heart, and other tissues (Stem pp). In some adult tissues, such as bone marrow, muscle, and brain, "discrete populations of adult stem cells generate replacements for cells that are lost through normal wear and tar, injury or disease (Stem pp). Scientists believe that stem cells may become the basis for treating diseases such as Parkinson's disease, diabetes, and heart disease (Stem pp). As scientists expand their knowledge of about stem cells, it may become possible to not only treat diseases, but to screen new drugs and toxins, and understand more about birth defects as well (Stem pp).

Unlike any specific adult cell, embryonic stem cells are undifferentiated cells that have the ability to form any adult cell, and can proliferate indefinitely in culture (Embryonic pp). Using fourteen blastocysts obtained from donated, surplus embryos produced by in vitro fertilization, James Thomson and a group of University of Wisconsin biologists established five independent stem cell lines in November 1998, the first time human embryonic stem cells had been successfully isolated and cultured (Embryonic pp). The embryos used in the work were originally produced to treat infertility and were specifically donated to the project with the informed consent of donor couples (Embryonic pp).

Embryonic stem cells are of greatest interest due to their ability to develop into virtually any other cell produced by the human body, thus in theory, "if stem cells can be grown and their development directed in culture, it would be possible to grow cells of medical importance such as bone marrow, neural tissue or muscle (Embryonic pp).

It is likely that the first potential applications of human embryonic stem cell technology will be in the area of drug discovery because the ability to grow pure populations of specific cell types offers a "proving ground" for chemical compounds that could have medical importance (Embryonic pp). This ability to treat certain cell types with chemicals and measure their response offers a short-cut to sorting out chemicals that can be used to treat certain diseases that involve those specific cell types (Embryonic pp). In other words, stem cell technology would allow for the rapid screening of hundreds of thousands of chemicals that today are tested through much more time-consuming processes (Embryonic pp).

Because the earliest stages of human development are difficult or impossible to study, human embryonic stem cells offer insights into developmental events that cannot be studied directly in humans in utero or fully understood through animal models (Embryonic pp). Knowledge of the events that occur during the first stages of development has potential clinical significance for preventing or treating birth defects, infertility and pregnancy loss (Embryonic pp). Moreover, knowledge of normal development could allow the prevention or treatment of abnormal human development, such as screening drugs by testing them on cultured human embryonic stem cells might help reduce the risk of drug-related birth defects (Embryonic pp).