The human heart beats approximately 35 million times every year, effectively pumping blood into the circulation via four different heart valves. Unfortunately, in over 4 million people each year, these delicate tissues malfunction due to birth defects, age-related deteriorations, and infections, causing cardiac valve disease.
Today, clinicians use either artificial prostheses or fixed animal and cadaver-sourced tissues to replace defective valves. While these prostheses can restore the function of the heart for a while, they are associated with adverse comorbidity and wear-down and need to be replaced during invasive and expensive surgeries. Moreover, in children, implanted heart valve prostheses need to be replaced even more often as they cannot grow with the child.
A team lead by Kevin Kit Parker, Ph.D. at Harvard University's Wyss Institute for Biologically Inspired Engineering recently developed a nanofiber fabrication technique to rapidly manufacture heart valves with regenerative and growth potential. Andrew Capulli, Ph.D. and colleagues fabricated a valve-shaped nanofiber network that mimics the mechanical and chemical properties of the native valve extracellular matrix (ECM). To achieve this, the team used the Parker lab's proprietary rotary jet spinning technology in which a rotating nozzle extrudes an ECM solution into nanofibers that wrap themselves around heart valve-shaped mandrels.
"Our setup is like a very fast cotton candy machine that can spin a range of synthetic and natural occurring materials. In this study, we used a combination of synthetic polymers and ECM proteins to fabricate biocompatible JetValves that are hemodynamically competent upon implantation and support cell migration and re-population in vitro. Importantly, we can make human-sized JetValves in minutes –much faster than possible for other regenerative prostheses," said Parker.
To further develop and test the clinical potential of JetValves, Parker's team collaborated with the translational team of Simon P. Hoerstrup, M.D., Ph.D., at the University of Zurich in Switzerland, which is a partner institution with the Wyss Institute. As a leader in regenerative heart prostheses, Hoerstrup and his team in Zurich have previously developed regenerative, tissue-engineered heart valves to replace mechanical and fixed-tissue heart valves. In Hoerstrup's approach, human cells directly deposit a regenerative layer of complex ECM on biodegradable scaffolds shaped as heart valves and vessels. The living cells are then eliminated from the scaffolds, resulting in an "off-the-shelf" human matrix-based prosthesis ready for implantation.