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Gene therapy takes another step forward, treating disorders with viruses.

 

Beta-thalassemia might sound like the name of a planet from a science fiction novel, but the truth is a little uglier. Beta-thalassemia is a sever blood disorder which causes a life-threatening case of anemia. Anemia can appear in many forms, but the basics behind the disorder are the lack of the ability of the blood to sufficiently oxygenate the body. This can be from a simple lack of red blood cells to deformities in the hemoglobin molecules in the blood stream, among other things.

Beta-thalassemia is a genetically inherited blood disorder and so the promise of the emerging field of gene therapy looks at least optimistic for treating such diseases. So far there has been one case of beta-thalassemia world-wide which has shown to have been possibly cured through gene therapy. The French boy, whose name was not immediately available, was diagnosed with beta-thalassemia at age three and had lived with the disease for fifteen years. The unlikely savior in this case was a genetically modified strain of human immunodeficiency virus (HIV) -- the same dreaded virus that causes autoimmune deficiency syndrome (AIDS).

One of the most common ways to treat anemia disorders is by way of weekly blood transfusions. This comes with its own complications though, as a process known as chelation is often then required to remove excess iron from the blood before it damages delicate organs.

The treatment, pioneered by Dr. Philippe Leboulch and colleagues from the University of Paris, instead uses a genetically modified version of HIV to supplant the body’s defective blood-production stem cells with healthy cells. This is no simple process: first they harvested the same stem cells from the patient’s own bone marrow. Then they treated the extracted cells with the modified HIV virus which inserted an undamaged copy of the previously defective chromosome 11 gene, effectively replacing the damaged version. Next, the patient underwent chemotherapy to destroy the remaining stem cells in his bone marrow. And finally, the new stem cells were injected, completely replacing the previously malfunctioning cells.

Though the process has only been completed on one patient to date, it was a resounding success. Nearly two years later, the patient has been able to cease taking transfusions and get on with a relatively normal life.

This is not the first case of a modified HIV strain used to treat a genetic illness. Other French researchers had used an engineered version to cure two children with adrenoleukodystrophy, a very rare genetic disorder that eventually kills its bearer by slow destruction of the brain’s myelin sheath, eventually causing nerve impulses to be unable to be transmitted or received from the nervous system and the failure of the adrenal glands.

Gene therapy is only just beginning to get its grip on medicine. Many other cases of marked improvement due to these therapies can be found in medical journals and in various places on the internet. Using HIV is not a common practice yet, possibly due to the stigma of its deadly AIDS-causing strains. And there may still be some apprehension over continuing to modify the virus for therapeutic uses in that it may be possible to create a super HIV which could be even more prolific than current versions.

However, to see that medicine is now using virus engineering on what once was simply a perceived death sentence to cure other life-threatening diseases and disorders seems to show a large commitment and great progress by medical science.

 



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RE: Misleading title
By PCR on 9/16/2010 2:00:26 PM , Rating: 2
quote:
I would've liked to see "Despite having recieved a modified HIV virus the patient has no chance of contracting full blown AIDS" inserted into the article somewhere. Just for reassuring purposes....


Not a chance, the modified virus is completely different than the actual HIV virus. The main reason they employed the use of the HIV virus is its ability to integrate certain genetic elements into the human genome. This gives them the ability to put in the modified (corrected) gene for the beta globulin chain in hemoglobin, which eventually leads to the cure.

All the virulence factors and the genetic elements that actually cause AIDS were removed from the virus.


RE: Misleading title
By tmouse on 9/16/2010 3:33:28 PM , Rating: 3
The concern I have with this and other virus mediated transfer mechanisms is first the integration is going to be random (now there may be a lot of extra space to insert into the genome where there will be no consequences but the fact is with the discoveries of nontranslated small RNA families we simply do not know how much "junk" DNA there is). Second virus are really adaptable and love to recombine, so if the patient ever gets real AIDS will any of the modifications result in something potentially worse? The simple answer is we do not know. I firmly believe targeted recombination is the only safe path to choose.


RE: Misleading title
By captainBOB on 9/16/2010 11:35:01 PM , Rating: 2
There is no "Junk DNA" it's "Noncoding" and "Coding" DNA now. And while viruses are commonly used as vectors in the research stage, they won't use such a method in the final product.


RE: Misleading title
By tmouse on 9/17/2010 7:42:38 AM , Rating: 5
Actually if you bother to notice, I did put junk in quotes. The point is we simply do not know what is coding or non coding anymore. Traditionally coding meant producing templates for translation, now we are seeing entire families of small non protein template RNAs whose functions are regulatory in nature. Add to this highly conserved SNPs hundreds of thousands of base pairs from the genes their currently associated with which strongly suggests some conservation pressure outside of producing a protein product so we are just beginning to unravel the real story.

Your dead wrong about not using virus in the final product, that absolutely is the end point for some of this research, I have sat on many NIH peer review panels and I can assure you of that.


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