It is a medical treatment, which consists of the insertion of genes that are absent, that do not produce the proteins that should or do not do it correctly, with the aim of modifying the genetic information of the patient, to avoid or cure genetic diseases.
It consists of transferring genetic material to the cells or tissues of the individual, to make the cells fulfill a new function or to repair or intervene in an existing function.
Gene therapy represents an innovation for medicine, in terms of how to treat genetic diseases. It has been postulated as the best alternative, but at the same time it has been the greatest challenge, because it is the most complex technique.
Its main advantage is that it attacks the root of the problem, which is the defective gene that causes the disease, by transferring the correct version of it.
On the other hand, the main and greatest challenge is that the transferred genetic material is correctly directed to those cells or tissues that require the gene to exert its function or that the introduced gene be regulated in the most similar way to that of healthy people.
There are three strategies or ways to apply gene therapy, which are:
- Ex vivo: consists of the extraction of the cells that must be repaired in the patient. They are repaired in the laboratory and later are reimplanted in the body of the person being treated.
- In situ: consists of introducing the repair gene into the defective cell or tissue directly.
- In vivo: it consists of the direct administration of the corrector gene to the patient, so that it reaches the point to be treated.
In order for gene therapy to be carried out, a vector is necessary, which is the vehicle that transports the gene into cells. This can be viral or non-viral.
Viral vectors are: retrovirus, adenovirus, adeno-associated virus, and herpesvirus. Non-virals are: particle bombardment, direct injection of DNA or RNA and the introduction of molecules that can be recognized by the receptors of the target tissue or cell (receiving the therapy).
The first attempt to transfer a gene to humans was made in 1970 for hyperargininemia, which is an autosomal recessive disease due to a mutation in the liver arginase I gene. This disease is due to severe neurological abnormalities in affected children. It is known that two children, who were injected with the "Shope papilloma" virus, which produces warts in rabbits, were treated as a source of arginase I. However, the results are unknown, since they were never published. Another test was conducted in 1980 in Italy and Israel for beta-thalassemia disease, but the results were also not published.
In 1988, the first gene transfer protocol was approved, the results of which were published. This official protocol was carried out with two girls suffering from ADA (adenosine deaminase) deficiency. The ADA gene was inserted ex vivo into peripheral blood lymphocytes and although the girls improved, it could not be determined exactly what the true therapeutic effect was due to.
Today, despite advances in gene therapy, which is being widely applied in cancer treatment, there is much to improve and it remains an experimental technique.
