Press Release

Eccles Institute of Human Genetics
University of Utah

RELEASE DATE: Nov. 2000

contact:
Connie Barth -- (801) 585-6135

How to Build an Artery
Background Information

SALT LAKE CITY, Utah -- Each year, 750,000 heart bypass surgeries are performed on patients in the United States at a cost of approximately $40,000 per patient. To perform the operation, doctors take veins from elsewhere in the patient’s body and use them to replace dysfunctional arteries. The trouble is that veins and arteries aren’t the same and, as a result, veins used in bypass surgeries don’t perform nearly as well as the original arteries. If a way could be found to make new arteries, these patients might live longer.

So how do you make an artery? asked Dean Li, M.D./Ph.D., a cardiologist at the University of Utah’s School of Medicine. First he decided to investigate the differences between veins and arteries, so he chose to examine hereditary haemorrhagic telanglectasia (HHT), a human disease in which arteries and veins are interconnected instead of distinct, as is normal. Another laboratories had already identified the gene responsible for HHT, but Li decided to figure out how the gene causes HHT. By understanding the how the gene works normally Li hoped to learn more about how arteries develop – and why things go wrong when the gene is damaged..

Li is also a researcher with the Human Molecular Biology and Genetics program at the Eccles Institute of Human Genetics, so his lab is experienced in investigating gene function. They theorized that the role of the HHT gene, which is known as Acvrl1, is pivotal in the correct development of arteries and veins in developing embryos. Then if the gene isn’t working correctly, arteries and veins don’t develop separately, causing blood circulation problems ranging from massive nosebleeds to death.

Li chose the mouse as a model animal to study the role of the HHT gene. Evidence to support Li’s theory was assembled from several experiments, including injecting ink into the hearts of normal and mutant embryonic mice to follow the flow of blood. In the mutant mice, the blood stayed near the heart because the interconnected veins and arteries provided a circular path for the blood to follow, rather than travelling the normal route through the whole length of the embryo.

Li’s experiments showed that the HHT gene does play a pivotal role in the development of arteries and veins. His results are presented in this month’s edition of Nature Genetics. His discoveries could be used by bioengineers to make new arteries for bypass surgeries and is helpful in cancer research.

Additionally, human HHT patients may see some help from Li’s research in the future. Although HHT isn’t a widely-known disease, Jamie McDonald, a genetic counselor at the University of Utah’s HHT Clinic, believes it is vastly under-diagnosed. The U.’s clinic is one of only four in the United States, and approximately 95% of its patients are from out-of-state. McDonald draws on her own experience as a person with HHT to help counsel other patients in how to deal with the disease.