Predicting tissue growth in heart valves - cracking the code
Since the first successful valve implantation in 1960, more than 70 different types of prosthetic valves have been implanted in millions of patients throughout the world. These prostheses share one major shortcoming: they do not consist of living tissue and, therefore, risk rejection by the body, require permanent medication and are prone to wearing out or breaking. Newborn babies with a congenital heart valve defect face an even bigger problem, as their implants have to be replaced repetitively to keep pace with the growing heart. 280,000 patients receive heart valve replacement surgery annually.
In this project, we use "in situ" tissue engineering to design a synthetic heart valve that will develop into a living valve once implanted and lasts for a lifetime. Controlling heart valve growth is a crucial design factor. It is well known that heart valves, like numerous other biological tissues, adapt to mechanical stimuli. Yet, the growth process itself is to be completely understood. We are particularly interesting in identifying the driving mechanical force of the growth process.
The keystone of this project is the design of a finite element framework with which we aim to capture and predict heart valve tissue growth and remodeling after implantation. An extensive experimental data timeline, from fetal to adult human native valves, of mechanical and structural data is being generated to verify this modeling framework (Figure). Additionally, we are designing novel experiments to study growth in tissue-engineered constructs and unravel the driving forces behind growth, which are to be implemented in our numerical model.
Understanding and, ultimately, predicting tissue growth and remodeling will be a giant leap forward in optimizing the designs of tissue-engineered heart valves that will last for a lifetime.