The Future of Healthcare: Gene Therapy
Gene therapy is the utilization of genes to treat or prevent disease. Instead of administering drugs or performing surgery, genetic material is either created, modified or repaired before inserting into patients’ cells. Gene therapy is a potential treatment for inherited disorders and cancers, but it is very risky so it is currently only tested for diseases with no cure.
Gene therapy can involve:
- replacing mutated and damaged genes with a healthy ones
- inactivating genes that is not working properly
- inserting new genes into the body that will combat, prevent or cure the disease
How does gene therapy work?
Genetic materials are introduced into cells to compensate for abnormal genes or to produce beneficial proteins. If an important protein is malfunctioning or missing, gene therapy is advantageous in that it can introduce a normal copy of the gene responsible for that protein. The normal copy will replace the function of that protein.
Since a gene directly inserted into a cell does not function properly, a vector is required to deliver the new gene into the cell. The vector is usually a genetically engineered virus that delivers the new gene by infecting the cell. These viruses are modified so they cannot cause a disease in the patients. The vector virus can be given by injection or intravenously at the target area where it is then taken up by the cells. An example of potential vectors are retroviruses which can integrate their genetic material along with the new gene into the chromosomes of the human cells. The new gene, now part of the chromosome, can then be replicated and expressed by the cell into functioning proteins. Another example of vectors are adenoviruses and they have the ability to introduce genetic material into the nucleus but the chromosomes are not affected. The DNA material is left free in the nucleus and is transcribed just like any other gene in the cell. However, since the gene is not integrated into the chromosome, it is not replicated during cell division so any descendants of that cell will not carry this extra DNA. As a result, gene therapy with adenoviruses will require readministration as the cells divide and grow. Gene therapy may also be performed in vitrowhere cells are taken from the patient and exposed to the vector in a laboratory setting. The modified cells are then returned to the patient.
Gene Therapy Issues
Although promising, gene therapy have many issues that must be addressed. Gene delivery and cell targeting needs to be improved and consistent before the widespread use of gene therapy. Additionally, the new gene inserted must be controlled precisely to avoid any adverse effects. Due to gene therapy being a relatively new medical therapy and having very limited studies, the risks are unpredictable. Studies have shown that gene therapy can lead to adverse effects such as toxicity, inflammation and cancer. As a result, gene therapy is predominately only performed in a research environment. However, the National Health Service of the United Kingdom recently approved funding for the gene therapy Strimvelis which can be used to treat Severe Combined Immunodeficiency due to Adenosine Deaminase deficiency (SCID). Gene therapy is a promising medical advancement that may cure some diseases in the future.