Microencapsulation — An alternative approach to gene therapy

Non-autologous somatic gene therapy' is a novel approach to gene therapy which does not depend on genetic modification of the patient's own cells. Recombinant cell lines secreting a desired therapeutic gene product can be implanted into different patients requiring the same product replacement. Graft rejection is avoided by enclosing these cells in immuno-isolation devices whose permeability excludes the host's immune mediators but permits the transit of nutrients and recombinant gene products. The feasibility of this strategy is demonstrated by expression of recombinant human enzymes, hormones and coagulation factors from fibroblasts or myoblasts enclosed within alginate-poly-L-lysine-alginate microcapsules. Its clinical efficacy is demonstrated by the correction of pathological phenotypes in murine models of human endocrine and lysosomal storage diseases. Hence, this approach may lead to a potentially cost-effective method of gene-based therapy.