Transplantation of microencapsulated hepatocytes for liver function replacement

Recent advances in cell biology and biotechnology have lead the way for a greater understanding of cell function and the potential therapeutic use of transplanted cells for treating a wide array of illnesses. Treatment of disease by transplantation of normal healthy cells, for the replacement of specific biological deficiencies or as a form of auxiliary support for a failing organ, offers important therapeutic applications and also serves as a model for assessing cellular physiology. In the long-term, cell transplantation may also have potential in the development of artificial organ support systems for sustaining patients with severe and chronic diseases such as diabetes, liver failure, endocrine and exocrine disorders, neurological abnormalities, and congenital metabolic defects. Several groups have demonstrated the feasibility and efficacy of cell transplantation in providing specific function in various experimental animal models of human disease. However, without adequate immunosuppression, complications due to tissue rejection remain a significant problem. Microencapsulation of cells within a synthetic semipermeable membrane, prior to transplantation, has been proposed for circumventing immunological complications following transplantation. The microcapsule's semipermeable membrane allows permeant molecules to freely diffuse across while preventing the microencapsulated cells from escaping. This membrane also keeps unwanted substances, such as cells and antibodies, from entering the microcapsule. Thus, microencapsulation provides an innovative and unique technique for the transplantation of foreign tissue and cells without the need for immunosuppression.