It was the ’70s when French Anderson sent the New England Journal of Medicine article which anticipated the possibility of cure hereditary diseases by inserting genes into the body by replacing missing or defective ones. “Unprintable because only fiction,” said the magazine. In 1990, Anderson and Michael Blease managed the impossible and concluded the first successful gene therapy that he intervened on the child of 4 years, Ashanti De Silva, destined to die of immune deficiency because it lacks the gene that produces the enzyme ADA. Today, worldwide, hundreds of experimental interventions that using gene therapy.
What are the problems, opportunities, the hopes to have to used this frontier of medicine?
When we talking about gene therapy, we intend to transfer genetic material to prevent or cure a disease. In practice, we try to transfer into diseased cells genetic code “functional” system, which replace the missing or defective gene. Candidates for this type of therapy are some hereditary diseases, in which there is one and the same genetic defect (monogenic), various infectious diseases are not curable with standard antiviral treatments (HIV) and certain cancers such as melanoma, leukemia, sarcomas and tumors of the nervous, gastrointestinal, uro-genital and gynecological problems. To achieve effective therapeutic obstacles to be overcome. First, we need to know the gene responsible for the disease in laboratory cloned and then play the correct version and working. Then we must have a carrier that allows us to insert DNA that we produce in the diseased cell. This vector should be efficient, safe, selective and penetrating. Finally, depending on the disease, we must understand if it is more convenient to intervene directly in cells and tissues of the patient (in vivo) or if “treated” by the isolated cells, cultured in the laboratory and then reinsert (ex vivo). The choice of carrier depends on the length genetic code to be inserted, the type of target tissue, the quantity, quality and durability of expression to be obtained for the gene concerned. In ex vivo gene therapy can be used physical carriers such as electroporation and microinjection, but also liposome’s , lipid vesicles that can serve as ‘boxes’ of transport. However, are the most widely used viral vectors. Viruses are naturally capable of delivering nucleic acids and enter the cell and this quality makes them ideal for gene therapy, especially in vivo. Are designed to be inactive, individuals of viral genes, which are inserted in place of the therapeutic genes of interest may be administered to the patient.
All this, however, it is not enough.
The efficiency of transfer and the clinical results are proportional to the location where the genetic code we produce is inserted, the duration of expression and the body’s immune reaction to the virus or transformed cells, in some cases capable of limiting the effectiveness of therapy. These factors are relevant: an incorrect position may not allow the reading stimulate oncogenes or deactivate other genes protectors, a non-permanent, which is transmitted to daughter cells, prevents the long-term therapeutic effect. Essentially, there are numerous obstacles to overcome to make this effective and safe therapeutic technique. Much has been made, the technology was refined and great results are at the gate, if not already present in many children before the incurably ill. Certainly, the possibility of modifying the genetic complement of the cell for correcting errors that feed diseases and suffering is constitute something to incredibly exciting and stimulated. But we must pay attention to the risks that these new technologies can hide. First of all, a possible involvement of germ cells, which would transfer to the children of genetic manipulation implemented. Second but not second order, the appropriation of these methods by biopolitical bodies, inspired and motivated by eugenic deviance, as was done in the past to select a superior race.
Translated by Martina Delser