Published: 10/17/2014 - Updated: 01/07/2018
Author: MSc. Miriam Reyes
Gene therapy consists of inserting functional copies of genes to take the place of those with defects, or that are absent in an individual’s genome. This therapy is performed in cells and tissues with hopes of treating severe diseases, either acquired or hereditary.
This therapy currently has several different focuses, although in most studies it is called gene addition therapy when a gene is copied and inserted into the genome, and when it is introduced into the host cell solely for the purpose of compensating for a defect. If equivalent recombinant therapy is performed, this process eliminates the defective copy and exchanges it for a functional one, this is known as gene substitution therapy.
Gene therapy, which is still being developed, considers the following factors:
- For acquired diseases, like cancer, different strategies are used, like inserting tumor cells with specific suicidal genes, or inserting tumor antigens to strengthen the immune response.
- Gene covering: which is not considered to be a complete cure for the patient, but rather is meant to improve therapy for a specific disease.
- Therapy for monogenic hereditary diseases: used in these conditions when the defective protein cannot be administered, or when this is not effective. The defective or absent gene is then provided.
- Somatic gene therapy: this therapy is performed in an individual’s somatic cells, whereby the changes implied in this therapy only take place in said patient.
- In vivo therapy: cellular transformations that takes place inside the patient’s body that is receiving the therapy.
- Ex vivo therapy: cellular transformation carried out by a tissue biopsy of the patient. The already transformed cells are then later transplanted.
- Germinal gene therapy: this takes place in the patient’s germinal genes (recently produced genes), which causes the changes provoked by the therapeutic genes to be hereditary. This therapy, however, is not used currently due to both ethical and legal questions.
Viruses and gene therapy
Today, viruses are the most commonly used vectors for these tests, as genetically, they can be altered to stop being pathogens, and to carry genes from other organisms. There are other types of non-viral vectors, however, that have also been used for these purposes.
This therapy uses gene vectors. Due to the wide variety of situations they can be used in, the following characteristics must be observed:
- It must be reproducible, stable, and allow the insertion of other genetic material, without size limitations. It must be easy to produce and store.
- It must allow transduction both in cellular divisions as well as in those that are not proliferating.
- Specific therapeutic gene integration must be possible.
- It must be able to recognize and act upon specific cells.
- The gene’s therapeutic expression must be regulated.
- It must not contain elements that could provoke an immune response.
- It must be completely characterized.
- It must be inoffensive and must not produce side effects (or they should be kept to a minimum).
- Production costs must be reasonable.
The vectors are to contain desired elements that are to be inserted into the patient, which would not only be functional genes, but the necessary elements for their expression and regulation; they could be developers, strengtheners, or specific sequences that allow them to be controlled under certain conditions.
Gene therapy is meant to cure hereditary diseases (the majority of them are cause by defective genes) by introducing healthy genes. This therapy can also be applied as treatment for illnesses like cancer, certain infectious diseases like AIDS, hepatitis, hypercholesterolemia, are arteriosclerosis, or to neurodegenerative diseases, like Parkinson’s disease or Alzheimer’s. It can also be used for chronic diseases, like rheumatoid arthritis.
We therefore have information regarding new therapies created by science, and yet, we still must not ignore the factors that are truly causing these diseases. It sometimes seems like science advances slowly when truly miraculous cures can be had through deeply profound dietary changes, as well as life and mind changes. Food and thoughts not only influence cells, tissues, and the entire body, but they are capable of changing their information and transforming cells, genes, tissue, etc., into a strong and healthy body.
Revised by: Dra. Loredana Lunadei on 01/07/2018
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