Cardiovascular disease happens to be a major cause of death all over the world. Treating it is not something easy. The disease causes problems on the patients’ blood vessels. Once this happens, it requires complex bypass surgery.
Researchers from the Morgridge Institute for Research have been working towards a dream to create artery banks. These are similar to blood banks. The artery banks will have readily available material to replace diseased arteries during surgery. The work of regenerative biologist, James Thomson, puts science a step closer to that.
Thomson’s lab shows a better way of growing smooth muscle cells from pluripotent stem cells. The work identifies a potential drug that could reduce post-surgical risks in the patients who go through bypass surgery.
Thomson said that they decided to focus on blood vessels since cardiovascular disease is a major cause of death all over the world. In the U.S. for instance, heart disease and stroke are the number 1 and number 3 causes of death respectively. This research has impacts beyond making transplantation vessels. It is a stepping stone to advanced tissue engineering.
The production of arteries in the lab requires two important cell types:
- Endothelial cells
- Smooth muscle cells
The lab demonstrated different methods of generating and characterizing endothelial cells while new research mainly focuses on smooth muscle cells.
Jue Zhang, the lead author, said that widely used growth factors for production of smooth muscle cells from stem cells can cause intimal hyperplasia. It is a common reason why bypass graft fails. In intimal hyperplasia, part of the arterial wall thickens causing the blood vessel to narrow.
Zhang said that they wanted to have a protocol that could reduce risks of intimal hyperplasia.
Healthy smooth muscles should have the ability to contract. This helps them in distributing blood all over the body and regulating the blood pressure. The researchers identified, using a high throuput screen, a small molecule called RepSox with the potential to produce cells that could contract. RepSox inhibits intimal hyperplasia. It is cheaper than the growth factors and is a good option.
RepSox has characteristics that make it a good drug candidate for reducing post-surgery complication risks. The stem cell based high throughput screen could be used as a strategy to identify drugs that restrict blood vessels narrowing.
These findings bring scientists a step closer to improved treatment for cardiovascular disease. However, cell maturity needs to be addressed as the next challenge. This is according to Zhang. He says that this cell type is better than efforts from earlier on but it is still not mature. It is important that we induce the cells to make them more mature so as to make them more similar to our native artery. This will make them more functional.
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