Genetic Engineering in Medicine

Genetic engineering has a broad variety of applications in the medical world. Because this biotechnology can modify the organic parts of an organism's genetic code, it may be used to strengthen immunity or even to remove ("weed out") diseased cells. Scientists are pushing the frontiers of both science and medicine. Let's talk about some of the types of medicines that are being created using today's genetic engineering technology.

Pharmacogenomics: Every human being (excluding some exceptions) has a unique genetic structure. So, then, why does everyone receive the same types of medicine for their different circumstances?

Pharmacogenomics is a new branch of pharmeuceutics, which aims to tailor medicines to work with an individual's unique genetic structure. This entire branch is based upon the belief that drugs made to work with one specific genetic make-up will be far more effective than what is currently in use. Pharmacogenomics is very new and has only been around for about five years.

Vaccines: Vaccines are the most effective form of disease prevention in the world, except for clean water. There are numerous ways to use genetic engineering to manufacture vaccines and antibiotics on a large scale.

First, scientists determine which gene in a pathogenic, or disease-causing, virus stimulates the production of antibodies in the human immune system. The section of DNA containing this gene is isolated and then placed into a non-harmful virus, such as the one used to vaccinate against smallpox many years ago. This is usually accomplished by the use of a plasmid, which acts as chromosomal DNA and replicates in the new bacterium where it has been incorporated. The new virus, containing the recombinant DNA, is used as a vaccine and injected into patients.

Genetically modified vaccines are much safer than conventional ones because they do not expose the patient to the actual virus, as it may sometimes lead to accidental infection.

Gene Therapy: Gene therapy deals with medical conditions by introducing specific genetically engineered genes into the cells of a patient.There are two types of gene therapy: Somatic cell and germ line.

Somatic cell- This form of gene therapy deals only with non-reproductive cells within the body (somatic). Instead of introducing new cells, somatic cell gene therapy modifies already existent ones. The effects of somatic cell gene therapy are not inherited in offspring and will only affect the individual who is treated.

Usually, the desired genes will be placed in another non-harmful virus and injected into a patient. This process attempts to introduce the gene into millions of cells in the patient's body. However, accomplishing this is a very difficult task and the process will often not work. In the future, though, it could be more capable of expressing certain, helpful genes in those who need it.

Germ Line- Germ line therapy occurs at a very early stage of the development of an organism, so that all cells that duplicate from it, will all possess the desired gene or modified DNA. First started in the 1980s, germ line therapy has become an easy and very commonplace process. Nowadays, most scientists are able to alter an animal's embryo at birth.

Because it allows scientists to alter an organisms genetic code before it is born, germ line therapy can be used to remove unwanted genes for crippling muscle or life-threatening diseases, to ensure that offspring are not born with them. Still, the effects of this form of gene therapy on humans are still very much unknown.

In the future, this technology could be used by parents to choose desired traits for their offspring prior to their birth. This method of gene therapy raises many serious ethical questions, prompting the AAAS (American Assosiciation for the Advancement of Science) to issue a temporary ban on it in the year 2000.

Gene Therapy Animation- Introduction
of a Therapeutic Agent into Liver Cells




Insulin and Other Hormones and Chemicals: The first synthetic human insulin was released in 1982. Until then, humans with an insulin deficiency, such as diabetes, were required to recieve transplants from the pancreases of other animals.

The process of creating synthetic insulin is quite simple. It relies heavily on DNA recombination. First a plasmid from a cell of the E. Coli bateria living within human intestines is removed and opened by using a special enzyme. Next the DNA coding for human insulin is inserted into the open plasmid and closed by another enzyme. The recombined plasmid is inserted into a host E. Coli cell and begins to replicate. Because all of the replicated cells are the same, human insulin production begins, according to the DNA implanted in the cell.

Using similar processes, scientists are also able to create large amounts of other substances useful in medicines, such as peptides which are short proteins. Many of these chemicals are used to alter hormone production around the body or genetically engineered to create proteins which stimulate the immune system. They may also be used to heal viruses, including certain types of cancer. We will speak more about these chemicals in a later post.

Stem Cells:
At the Democratic National Convention in July 2004, former US president Ronald Reagan hailed embryonic stem cell research as:

“(the) greatest medical breakthrough in our or in any lifetime”

Basically, embryonic stem cells are very young cells found in a mammal's embryo, which can be used to create many forms of tissue to repair or replace damaged organs in humans. They are especially useful because embryonic stem cells can be used to replace important tissue that does not grow back, such as that from a brain. Also, using embryonic stem cells to repair organs is much safer and more plentiful than using donated tissue.

So how do they do it? First, scientists remove a female egg cell and fertilize it in vitro (outside of the body) They allow the egg to grow in a blastocyst of a few hundred cells within the laboratory. A blastocyst is an embryonic structure that forms during the early stages of embryogenesis (the creation of an embryo). Then, scientists remove the inner mass of the embryo, containing the useful stem cells.

Embryonic stem cells are much more useful than other adult stem cells because they can create a much broader range of tissues. Adult stem cells are already specialized for creating a certain tissue, limiting their functionality in other parts of the body.

Scientists are also looking at extracting cells from a female's uterus or the ends of a baby's umbilical cord to repair tissue, but this is still a new and untested procedure. So far, no one has succeeded in curing diseases with adult stem cells, but embryonic stem cells are much more promising.

So, why the controversy?

During the process of harvesting the useful stem cells, the rest of the embryo is destroyed. Because of this, embryonic stem cell research has become a highly debated topic. Some believe that destroying the embryo is akin to murdering a human being, while others argue that the embryo is nothing but a collection of cells, still incapable of thinking or feeling pain as they have not yet reached the 28th week of gestation within the fetus.

Another advantage of using embryonic stem cells is that they are cross-species, meaning that stem cells from a human could be used to heal an animal, or vice versa. In one example, human embryonic stem cells were used to fix the spinal column of a paralyzed rat, enabling it to walk again and even run on a minature treadmill.

Stem cells could even be used to create clones.

Here's a video about some newer developments in the field of stem cell research.
Stem Cells: Of Mice and Men