This is the first of a series of articles dealing with those advances. What I plan to do is to try to put things into perspective: that is, to tell you how near I think we are to the fountain of eternal youth. I will start with gene therapy (GT) that has been an unfulfilled promise since the beginning of the 1990´s. GT has worked wonders with lab animals and cells, but not so with humans. In more than 300 clinical trials enrolling about 6000 patients, not one has been cured. And, to complicate things, it sadly ended the century under investigation by the FDA.
Gene therapy is the administration of genes to a patient for therapeutic purposes. It intends to restore a function that has been lost because of a defective gene by giving the patient a functional one. As you can see, it is a very simple concept--to replace a faulty gene for a healthy one. However, there are three practical problems: The isolation of the gene in question, the insertion of the gene in the right place in the genome and an appropriate vehicle to deliver the gene.
The first problem has been solved in all of the trials that have been carried out up to now. That is, the genes to be administered have been isolated and characterized. And with the Human Genome Project coming to an end in the very near future, there is no doubt that many more genes related to or associated with diseases will be isolated. Thus, this part of GT presents no problem at the moment.
The second problem has not been solved yet and there are few reports indicating what sort of advances are being made in this area. If you read my first article, you already know that for a gene to function properly it must be: a. expressed at the right time, in the right tissue and in the precise amounts, and, b. located in the right chromosome and under its normal regulatory sequences. Thus, if it is going to be done correctly, gene therapy should directly replace the defective gene with the healthy one. The way to solve this problem is to use a delivery vehicle or vector that inserts the gene into the right chromosomal location. At this time, there are no vectors capable of doing this.
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