The human body is relatively frail, it breaks down as we age and is susceptible to a wide range of ailments. Gene therapy is one of the methods which has been developed with the intention of making our bodies more efficient. It achieves this by replacing malfunctioning genes in our cells, and the new ones are introduced to the system to take the place of those that are no longer serving us.
There are two types of gene therapy. The first is known as in-body therapy, where researchers transport new cells within our bloodstream by using viruses. These organisms facilitate the reproduction of the cells as they are naturally designed to replicate. The first attempts at in-body therapy used the virus that causes the common cold, but scientists found that this wasn’t very effective because of the automatic immunity the body develops against it. A genetically modified adeno-associated virus has replaced this, as it is not known to cause any reaction in humans.
Out-of-the-body gene therapy involves removing the blood or bone marrow of a patient and separating immature cells. A modified gene is then added to these and they are reintroduced into the patient’s bloodstream by injection. The cells automatically go to the bone marrow where they mature and multiply, eventually replacing the defective ones. Doctors are working on refining this process in order to be able to replace all of an individual’s bone marrow or bloodstream. This would then enable them to treat diseases which affect the entire body, such as sickle cell.
Gene therapy will introduced one of its greatest achievements to the market recently – A cure developed for blindness, caused by the hereditary condition, retinal dystrophy. The procedure works by directly targeting the hereditary mutation which is the cause of blindness. New cells are injected into the patient in a 45 minute surgery. Within thirty days the majority of sufferers will experience vision improvements.
Made by Spark-Therapeutics, the product is currently known as SPK-RPE65. One of the obstacles that the company had to overcome in their development was to ensure that patients would not have an immune reaction to the treatment. This scenario has been the cause of at least one death in the past, when gene therapy was first introduced. There is still much speculation about how the product is received, but Sparks-Therapeutics is confident that it will eventually be met positively. In the company’s initial tests 27 out of 29 patients experienced a noticeable change in their ability to see, without any observed side effects. This product is expected to provide new insight into gene therapy altogether.
DAVID VISSERS 