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Gene therapy is a method of treatment that introduces foreign DNA or RNA nucleic acids into the body’s cells. The therapeutic effect is caused by the genetic information contained in the introduced DNA or RNA. It changes the defective genetic record of a sick person and causes the disease (mutated gene, defective genetic material) to be removed.
When is gene therapy used?
Gene therapy is used to treat hereditary diseases. Gene therapy is aimed at removing the source, that is, the immediate cause of the disease.
Currently, genetic diseases caused by mutations in one gene are most often treated with gene therapy. These include cystic fibrosis, haemophilia A and B, Duchebbe muscular dystrophy, SCID, familial hypercholesterolaemia, phenylketonuria, and sickle cell anemia.
Gene therapy can also help in the treatment of diseases caused by mutations in many genes, such as atherosclerosis, Parkinson’s disease, connective tissue diseases, and cancer caused by accumulated damage to genetic material.
Gene therapy is also used in the treatment of liver disease, pancreatic cancer, breast cancer and human papilloma.
Research is ongoing that offers hope for the treatment of other diseases through gene therapy. Importantly, gene therapy addresses the root of the problem, not merely treating the symptoms of the disease.
What is gene therapy?
Gene therapy is the introduction of a foreign stretch of DNA or RNA nucleic acid with the correct genetic record into the cell of a sick person. The mutated gene is thus replaced by the correct genetic record. Gene therapy can also modify the activity of individual genes so that the symptoms of the disease disappear. For this purpose, additional copies of those genes that are not working properly are introduced into the patient’s cell. Thanks to gene therapy, the function of a defective gene can also be blocked.
How are nucleic acids introduced into a cell?
Gene therapy may involve taking the patient’s genetic material (this applies to cells in the bone marrow and blood), “repairing” it outside the body, and then putting it back into the patient’s cells. Cells are collected from an organism ex vivo and sometimes multiplied in vitro to obtain the right amount of material.
So-called vectors are used to introduce nucleic acids into the patient’s cells.
The genetic material is directly or indirectly introduced into the cell. The direct method involves injecting a solution of plasmid DNA in saline (so-called naked DNA) into the tissue.
Indirect methods for introducing nucleic acids can be physical, biochemical, or biological.
The physical method involves introducing RNA or DNA into the cytoplasm or nucleus of a cell by locally and reversibly damaging the cell membrane.
The biochemical method is the use of chemical carriers of nucleic acids, most often cationic lipids or amine polymers. These carriers enter the cell through fusion with the cell membrane.
Biological methods involve the use of the so-called vectors, most often viruses. The viral genes are removed and the genes needed for therapy are inserted in their place. Then the vector (the biological gene carrier – the modified virus) is introduced into the body. The vector transfers the DNA used for gene therapy into the cell. Plasmids, i.e. circular DNA molecules which can replicate in the recipient’s cells, can also be used as vectors.