As the building block to living organisms, cells make up our bodies and perform a wide variety of different functions, all while being the smallest unit of the body. Depending on the tissue type, cells can be more or less specialized.
Genes are located deep within our cells, and carry genetic information in the form of DNA that provide the ‘code’ for our physical characteristics, and biological functions. It is important to note that some of our physical traits are not determined by genes alone, and can be caused by a combination of genes and an individual's environment. Genes are inherited from our parents, meaning individuals usually carry two of each gene.
When our DNA is altered, which can include it being missing, damaged, duplicated, and more, it can cause a genetic disease or disorder.
What is gene therapy?
In the grand scheme of pharmaceutical treatments, cell & gene therapies are relatively young methods, meaning there are respectively less treatments available on the market when compared to more traditional treatments. Gene therapy is, in essence, altering, replacing, adding, or removing a gene in order to target and treat a disease or disorder.
Gene therapy is particularly beneficial as many genetic disorders require lifelong treatments and management to maintain a quality of life, whereas gene therapy targets the problem in the gene at the most fundamental level, in hopes of significantly improving or curing the disorder altogether. Although gene therapy is incredibly promising, someone considering gene therapy must take into account the possible negative aspects, including intense side effects, the body's rejection of foreign or altered genes, and incredibly high costs of treatment.
In vivo vs ex vivo gene therapy
An important thing to note about gene therapy is that it is usually conducted with one of two main methods: in vivo, or ex vivo.
Due to the complicated nature of cell therapy, a patient's cells are sometimes extracted, with alterations to the gene or genes being done in a lab, then transplanted back into the individual receiving treatment. This is called ex vivo therapy. In comparison, in vivo therapy is done when the corrected or altered genes are delivered directly into the patient's body.
What is cell therapy?
Instead of altering DNA or a genetic code, cell therapy is done by transplanting, altering, or resorting sets of human cells to treat an ailment. Cell therapy is actually a relatively old treatment, with some common examples being used as far back as the first recorded blood transfusion in 1665, or more recently, the first bone marrow transplant in 1956. Following those major advancements, cell therapy has since evolved to involve a wide range of cells and treatments.
Cell transplants can be autologous or allogeneic. Autologous cells are harvested from the patient, making them their own donor after their cells are altered. Allogeneic cells are transplants from a universal or other applicable donor. For example, the bone marrow transplant mentioned above involved bone marrow being harvested from one identical twin, and given to the other twin.
As mentioned with gene therapy, there are a variety of possible negative outcomes when receiving cell therapy that must be acknowledged and considered, including cost, side effects, and rejecting cells from a foreign body.
The future of cell & gene therapy
As for specific ways that cell and gene therapies will evolve, as many of the therapies are young and yet to be approved, it may be a while before we know the full extent of capabilities these therapies have in store.