Encapsulation matrices for neurotrophic factor-secreting myoblast cells

Encapsulated-cell therapy is an emerging technology that entails implantati on of cell-containing devices that secrete therapeutic factors. One potenti al application of this technology is the delivery of neurotrophic factors t o treat neurodegenerative disease. These devices typically use an internal matrix to serve as a cell scaffold. This study compares collagen-coated pol yethylene terephthalate (PET) yarn scaffold versus collagen as a matrix for engineered C2C12 myoblasts. C2C12 cells transfected to secrete ciliary neu rotrophic factor (CNTF) were immobilized in matrices and encapsulated into hollow fiber membrane devices. Encapsulated cells were monitored in vitro f or viability, morphology, and factor secretion. Two independent methods (hi stology assessment and metabolic assay) were used to estimate viable cell d ensity; a high correlation between the methods was found. After 4 weeks, en capsulated devices with PET scaffold had an almost nine-fold greater number of viable cells compared to collagen. PET matrix devices contained a thick annulus of compact, highly oriented cells. Collagen matrix devices contain ed sparse viable cells in a thin rim. Secretion assays showed cells in PET matrix released approximately four-fold the amount of CNTF versus cells in collagen (averaging 542 and 129 ng/day per device for PET and collagen matr ix, respectively). The choice of encapsulation matrix was found to have a p rofound effect on cell morphology, level of secreted factor, and viability of encapsulated C2C12 cells.