Hydrogel-based non-autologous cell and tissue therapy

Many diseases are closely tied to deficient or subnormal metabolic and secr etory cell functions. Milder forms of these diseases can be managed by a va riety of treatments. However it is often extremely difficult or el en impos sible to imitate the moment-to-moment fine regulation and the complex roles of the hormone, factor or en,vme that is not sufficiently produced by the body. Immunoisolated transplantation is one of the most promising approache s to overcome the limitations of current treatments. Non-autologous (transf ormed) cell lines and allogeneic and xenogeneic cells/tissues that release the therapeutic substances are enclosed in immunoprotective microcapsules. The microcapsules avoid a lifetime of immunosuppressive therapy while exclu ding an immune response in the host. Research in this direction hers shown the feasibility of microcapsules based on hydrogels (particularly of algina te) for transplantation of non-autologous cells and tissue fragments. Numer ous technical accomplishments of the immunoisolation method have recently m ade possible the first successful long-term clinical applications. However, realizing the potential of immunoisolated therapy requires the use of seve ral factors that have received limited attention in the past but are import ant for the formulation of hydrogel-based immunoisolation systems that are highly versatile, potentially economical and can gain medical approval.