Mechanobiology: Growth & Remodeling
Biological tissue is a living tissue, which means it responds to changes of its surroundings. Growth and remodeling play an important role in this adaptation. They describe the change of mass and of properties of the tissue. Due to this functionality the arterial wall adapts for example to hypertension. As a malfunction an aneurysm can arise. It is crucial to get a better inside into the adaptation process. One way is to model growth and remodeling in a finite element analysis. In the following two methods to model growth and remodeling are briefly described.
The tissue changes mass depending on its stress and deformation. Thereby the density remains constant. That means an increase in mass results in an increase in volume by the same amount. In the pictures below you can see such a growth process. A quadratic block is stretched in one direction and starts to adapt to this deformation. The resulting geometry is a quadratic block again.
Turn over of collagen
Collagen has a half-life of a few months. Thus during maturity it continuously turns over. In this way the arterial tissue is able to maintain a preferred state. A dysfunction in this process can for example lead to an aneurysm. As old collagen is not always replaced with the same amount of new collagen a mass change is also possible. In the picture on the right you can see an aneurysm in its original shape and later when it is grown.
With the help of these methods we get a better understanding of the formation of aneurysms and other diseases. We want to determine growth parameters with an inverse analysis of CT scans to predict future growth.