Structure-function relations in elastic tissues: lessons for tissue engineering

The rapidly growing fields of tissue engineering and regenerative medicine are striving to direct the growth and development of tissue replacements that capture the mechanical function of native tissues. A particular challenge is the reproduction of load-bearing elastic tissues which must stretch and recoil with minimal energy loss. The major stumbling block in tissue engineering has been the inability to grow the important structural elastic fibers that are the main rubbery component in these tissues. The proposed research takes a completely novel and interdisciplinary approach to this problem by using tools from materials science and engineering to investigate the structural and functional development of elastic fibers in natural tissues. Our belief is that the best lessons for tissue engineering design will come from understanding the complex structural-functional relationships of developing fetal tissues and how these tissue adapt to alterations in their mechanical loading conditions. Using materials science and engineering techniques, we will describe the structural and mechanical changes in the elastic fibers during development from fetal to adult life (in cows): starting from the formation of a microfibrillar scaffold in early gestation. We will also examine the lobster and lamprey aorta: elastic tissues rich in microfibrils, but devoid of elastin. We hypothesize that the mechanisms of elasticity of the highly microfibrillar fetal elastic tissues are similar to those found in the lobster aorta and elastic tissues of other lower animals. We will also examine the structural/mechanical changes in aortic elastin structures as this artery undergoes dramatic remodeling during pregnancy. Understanding the mechanics of elastic tissue, and how its elastic mechanisms change during development and remodeling, will aid in the tissue engineering of arterial replacements.