Gene Therapy May Help Sickle Cell Anemia, Study Says

November 12, 2012

Gene Therapy May Help Sickle Cell Anemia, Study Says

A promising new gene therapy developed at the Salk Institute for Biological Studies may have found a cure for sickle cell anemia. The new technique uses the patient’s own skin cells to be placed into stem cells and then injected back into the patient. This is hoped to create a safe way to repair hematopoietic blood cells and change the sickle-shaped cells back into normal, healthy round cells.

This technique has never been tested on people. Studies need to be performed on animals first before human clinical trials would begin. So far, studies have been confined to infected tissue samples grown in a lab. If this treatment works for sickle cell anemia, then potentially it could be used to cure other genetic diseases caused by a single mutation, such as the blood disorder beta thalassemia.

Technique Specifics

Sickle cell anemia is caused by a mutation of just one gene – the beta-globin gene, usually known just as HBB. A skin sample is taken from a patient with sickle cell anemia. Cells are cultured from the sample to produce six specific genes and injected into a modified adenovirus of the common cold to make the new genes easily disperse throughout the body. The modified andenovirus is then injected into induced pluripotent stem cells or iPSCs. These cells are capable of growing into other types of cells, such as for blood cells.

And that’s just what the iPSCs do. Only these cells do not contain the mutated HBB gene, but a repaired version. It is hoped that by using a patient’s own skin samples, the body will not reject the new cells and eliminate all body cells with the defective gene. By using a modified cold adenovirus, researchers could both introduce the new gene into the body and not risk introducing a rapidly-reproducing harmful virus. Unlike other types of viruses, an adenovirus cannot reproduce inside of a human body.

Bone Marrow Transplants

Getting the modified adenovirus into a human patient’s body is as easy as giving an injection. Bone marrow must be grown in the lab and then transplanted into the patient’s bone marrow.

Bone marrow transplants are common therapies for patients suffering with sickle cell anemia, but the transplanted bone marrow is often rejected. Sometimes the bone marrow is not rejected but still causes severe side effects. Either way, the chances of recovery from a bone marrow transfer is very small or the chances of dying from complications are high.

About Sickle Cell

But these are chances many sickle cell patients are willing to take. Because of the defect in the HBB gene, their bodies make sticky, abnormally-shaped red blood cells that die quicker than healthy blood cells. In normal people, red blood cells carry oxygen throughout the body. Sickle-shaped cells carry minute amounts of oxygen.

Patients with sickle cell anemia suffer from learning disabilities, fatigue, severe pain if blood clots, swelling of the hands or feet and stroke. They also are more susceptible to getting other severe ailments such as pneumococcal disease. Patients with sickle cell anemia often die by the time they are 45.

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