concept is theoretically straightforward, but difficult to achieve in practice; principle entails stable introduction of gene into genetic complement of a cell, expression of gene achieves therapeutic goal; potential as a curative approach for inborn errors of metabolism and other conditions induced by presence of defective copy of a specific gene
Describe the current status of Gene Therapy.
role suggested by increased knowledge of disease processes; 2/3 of all gene therapy trials conducted to date aim to treat cancer (only a handful has shown therapeutic benefit); it has risks (pt. died in 1999, regulation & monitoring have increased); disappointing results thus far do not reflect any flaw in concept
What must happen for a desired gene to work in gene therapy?
must be packaged into a vector system, must deliver it safely inside intended recipient cell (hardest part)
What kinds of vectors can be used to effect gene transfer?
mechanism partly understood with retroviral vectors, mechanism of lipsome vectors or naked DNA less well understood
What 3 strategies are used as gene therapy protocols?
1. in vitro approach (most common, remove target cells from body, cultured in vitro & incubated with vector containing nucleic acid, altered cells reintroduced into pt's body); 2. direct injection/administration (nucleic-acid-containing vector into target cell); 3. alternative (in vivo) approach (method of choice) (development of vectors that recognize and bind to specific predefined cell types, administered by IV injection, only deliver nucleic acid to specified target cell, *no such system has been developed)