Cyclic mechanical strain regulates the development of engineered smooth muscle tissue

We show that the appropriate combinations of mechanical stimuli and polymer ic scaffolds can enhance the mechanical properties of engineered tissues. T he mechanical properties of tissues engineered from cells and polymer scaff olds are significantly lower than the native tissues they replace. We hypot hesized that application of mechanical stimuli to engineered tissues would alter their mechanical properties. Smooth muscle tissue was engineered on t wo different polymeric scaffolds and subjected to cyclic mechanical strain. Short-term application of strain increased proliferation of smooth muscle cells (SMCs) and expression of collagen and elastin, but only when SMCs wer e adherent to specific scaffolds. Long-term application of cyclic strain up regulated elastin and collagen gene expression and led to increased organiz ation in tissues. This resulted in more than an order of magnitude increase in the mechanical properties of the tissues.