Engineering functional tissues: In vitro culture parameters

Tissue engineering seeks to restore the function of diseased or damaged tissues through the use of cells, biomaterials, and biologically active molecules. The next generation of functional tissue replacements will likely require additional exogenous stimuli to achieve many of the important requirements for long-term clinical success. Two such requirements-physiologic mechanical properties and the ability to grow and remodel in a manner that allows for restoration of physiologic function-may be achieved by the judicious selection of in vitro culture parameters. Moreover, in vitro models are relevant not only to tissue engineering and regenerative medicine but also as platforms for high throughput screening of therapeutic drugs. In this chapter, representative studies of two diverse types of engineered tissues-cartilage and cardiac-are described in which in vitro culture parameters were manipulated in order to accelerate the growth, maturation, and integration of engineered tissue constructs and improve their biomechanical properties. In this regard the effects of culture duration, scaffold systems, bioreactors, growth factors, and mechanical conditioning are discussed. Given the rapid evolution of the field of tissue engineering, it is important to consider these in vitro culture parameters in conjunction with novel molecular and gene therapies and other emerging technologies.