Have a Cow

Lower back pain associated with degeneration of invertebral discs affects tens of thousands of people in the United States, but the team, Engineering the Intervertebral Disc, led by Dr. Jeremy Mercuri and Dr. Dan Simionescu, in Bioengineering, is attempting to change that. This five-person team has been working for three semesters on developing a tissue-engineered total intervertebral disc (IVD) replacement. An IVD is the layer of cartilage that acts as a shock absorber between vertebral bodies (back bones) in the spine. The idea is to create tissue-engineered IVD using discs from the tails of cows as a starting scaffold material. After studying literature to find the best surrogate to the human IVD, students found that a bovine (cow) IVD had the most similar size, structure and biochemical makeup.

The team is working towards removing the cow cells while still maintaining the native architecture and biochemistry of the IVD. Ultimately, the team will subsequently replace the cow cells that they removed with human stem cells. In order to remove the cow cells, detergents and agitation are used to ‘wash off’ the cells. The CI students are trying different methods to see which one works best, and if they are successful, they hope to apply for a patent. To date, the team has tried four or five different de-cellurization procedures and are now attempting to develop their own repeatable method. “The ideas essentially came from students reading literature and identifying different techniques and detergents that others have used in their own unrelated technologies,” Mercuri said.

The process has been challenging, but it is a hands-on experience that allows students to develop their research and critical thinking skills as bioengineers. The team meets every semester to go over what works and what doesn’t. “It has definitely been challenging to try and find a good process. It’s been a great learning experience. I feel like I learned a lot by just being here,” Clayton Compton, a junior Bioengineering major said. The team will continue working towards completing the process of creating the tissue-engineered IVD and completing their research. The students are careful about what they release to the public so they do not limit development of intellectual property, but they presented a poster at the 2015 Focus on Creative Inquiry Poster Forum.

Disc degeneration will affect most people at some point in their lives. The problems associated with degeneration of an IVD can decrease mobility, pinch nerves and cause pain. Multi-factorial degeneration is a especially problematic because it is caused by several different factors such as genetics, mechanics, and IVD nutrition. If the cells are malnourished, they are more likely to malfunction and break down themselves. There is no blood supply directly in an IVD, which creates a harsh environment, and can contribute to structural breakdown. This eventually results in the need for a replacement.

The overall goal for the Creative Inquiry team is to take human cells and place them in vitro on the structure of the decellularized cow disc and observe whether or not they can regenerate the entire tissue. Their hope is to get as close as possible to a healthy disc. The key difference between implanting a disc and currently available metal hardware is that the engineered disc will be able to grow and regenerate over time. The development of this technology may significantly change the way IVD replacements are developed in the future because the tissue engineered replacements will closely resemble the normal construction of natural IVDs, and will provide another option for those suffering from disc degeneration.