Hemophilia A, which causes internal bleeding in humans, is due to the dysfunction of the FVIII, a blood clotting factor. For patients with Hemophilia A, their FVIII refuses to function normally and just give its 1% of its normal activity. Today, treatment for Hemophilia A requires replacement of FVIII so that the activity of the patients FVIII will turn to at least 1-5%. But, the cost of this treatment is expensive. The objective of the study is to present an alternative to the current treatment of Hemophilia A by gene therapy.
Gene therapy has become successful when scientists used it to dogs and they’ve thought that it can be applied to humans as well. They injected AAV-cFVIII, a virus and a canine FVIII, to the vein of mice. AAV or adeno-associated virus was previously found to aid in the activity of canine FVIII. They took samples from the liver and they tested the samples to find its FVIII activity level. They did Coatest assay to find the activity of the canine FVIII in the mouse and the result was plotted and extrapolated against a standard curve.
Several other tests were performed to assess the efficiency of the different types of AAV in enhancing performance of the cFVIII in mice. They found out that there are two types of AAV (AAV6 and AAV8) are better in terms of efficacy compared with the rest of the types (AAV2 and AAV5). They also found that the gene transfer was most efficient with AAV8. They also found out that because dogs showed a high activity of FVIII than mice, they’ve concluded that dogs should be a better model for predicting effective doses to humans.
Suggestions include further study that will minimize toxicity and improving strength of the transgene promoter. Evaluation: The article wants to see how efficient the procedures are for gene transfer given the specific gene to a species and how efficient this gene therapy is for a species by looking at the activity of the FVIII and its effect to the species especially in terms of toxicity. This will be their basis for human application. The study is significant considering that their target is to find an alternative to the expensive treatment of Hemophilia A.
Their study will become a starting point for further studies in this gene therapy for humans. Of course, the experiments must be done to nonhumans first, before it could actually be applied to humans. Their methods are appropriate in finding accurate results for the study. The methods they used were to determine efficiency of the gene transfer to a species and to determine the activity of the FVIII. They applied statistical analysis to verify significance of the values they’ve obtained.
The conclusions are based on the data they’ve obtained. The study was conducting for months to account for many factors including developments over time. They’ve reported nothing inconclusive. They reported either efficient or non-efficient. They’ve provided adequate discussion to support their conclusion. But, of course, the variables they’ve considered are limited. It is possible that there are other serotypes of AAV that is more efficient than their AAV6 or AAV8. They did not report anything that is beyond their scope.
When they said the mice developed antibodies to FVIII, they reported it as is, and they didn’t mention that species who get gene therapy will also develop antibodies to FVIII or to at any extent. The study didn’t really focus on proving a hypothesis or not. It is rather giving recommendations to which factors could be used for gene therapy and how efficient it could be. It is more on suggesting which will be better for the procedure of gene therapy. This is a strong study because there is a very good application of the study.
And the methods they’ve employed are appropriate. The results of their study can be used for further studies to completely address the alternative treatment for the current expensive treatment for Hemophilia A. Reference: Jiang, H. , et al. 2006. Multiyear therapeutic benefit of AAV serotypes 2, 6, and 8 delivering factor VIII to hemophilia A mice and dogs. Journal of the American Society for Hematology. 108: 1, 107-115. Retrieved 16 April 2009 from http://bloodjournal. hematologylibrary. org/cgi/content/full/108/1