Featured Research

from universities, journals, and other organizations

Mechanical Forces Found To Exert Larger Role In Blood Vessel Health And Disease

Date:
July 23, 1999
Source:
Penn State
Summary:
Cholesterol, dietary fat, drugs and other chemical bio-regulators may get most of the media attention, but Penn State engineers have shown that mechanical forces, including shear stress, stretch and pressure, can play unsuspected but equivalent roles in some aspects of cardiovascular health and disease.

University Park, Pa. --- Cholesterol, dietary fat, drugs and other chemical bio-regulators may get most of the media attention, but Penn State engineers have shown that mechanical forces, including shear stress, stretch and pressure, can play unsuspected but equivalent roles in some aspects of cardiovascular health and disease.

Dr. John Tarbell, distinguished professor of chemical engineering, and associates in Penn State's Biomolecular Transport Dynamics Laboratory, recently showed that there is a one-to-one correspondence between certain effects of shear stress, the frictional force exerted by blood flow, and a growth factor that stimulates the production of new blood vessels. The Penn State group compared the effects of shear stress with that of vascular endothelial growth factor (VEGF) in laboratory tests with both human and bovine blood vessel tissue. VEGF is multifunctional and, in addition to promoting the growth of new blood vessels, it affects the ability of the cells on the interior surface of blood vessels, the endothelium, to allow fluid to pass through to the cells beneath.

The researchers showed that shear stress and VEGF not only cause similar changes in endothelium transport properties but also do so by the same chemical signaling pathways. Each of the tissue types the group investigated produces nitric oxide in response to shear stress, and nitric oxide is believed to be a key intermediate in the cell signaling cascade for both shear stress and VEGF, according to their recent paper.

Tarbell, who directs Penn State's Biomolecular Transport Dynamics Option for graduate study in the Life Sciences Consortium, notes that his group also investigates the effects of fluid flow as it passes across blood vessel walls. This transmural flow is six orders of magnitude or a million times slower than blood flow and amounts to a "seepage" through the wall's tissue matrix.

Nevertheless, even though the flow is slow, Tarbell and his associates have shown that it exerts shear stress that affects vessel function. For example, they have found that shear stress from transmural fluid flow stimulates the contraction of smooth muscle cells, which lie deep within the vessel wall. This may, in turn, contribute to the overall vessel contraction in response to an increase in blood pressure.

To estimate the shear stress levels on smooth muscle cells, the group used a computer simulation often used to model the flow of oil through sandstone. In future studies they hope to assess the relevance of the computational findings on live animals in addition to the cell culture systems they are currently studying.

Certain effects of fluid flows on smooth muscle cells become especially important when these cells are exposed directly to blood flow, for example, during angioplasty, vascular grafting or other surgical interventions, Tarbell notes.

In their recent laboratory studies with rat tissue, the Penn State group found that shear stress affects the contraction, growth and biochemical production rates of these smooth muscle cells in cell culture models which simulate both intact blood vessel walls and injured vessels where the cells are exposed directly to blood flow. Their results also suggest that exposed smooth muscle cells may take over certain endothelial cell functions when they experience shear stress from blood flow.

###

Tarbell and his research group recently reported these findings in two papers at the Summer Bioengineering Conference in Big Sky, Montana, June 16-20. The papers are: "Shear Stress and Vascular Endothelial Growth Factor (VEGF) Affect Endothelial Transport Properties through Common Signaling Pathways" by S. Lakshminarayanan, graduate student in chemical engineering, Y. Chang, graduate student in physiology, M. Hillsley, postdoctoral fellow, Thomas W. Gardner, associate professor of ophthalmology, and Tarbell; and "Effects of Flow on Vascular Smooth Muscle Cells" by S. Wang, postdoctoral fellow, R. Sharma, graduate student in bioengineering, S. Tarda, visiting scientist, Department of Mechanical Engineering and Science, Tokyo Institute of Technology, and Tarbell. The research was supported in part by grants from the National Institutes of Health.


Story Source:

The above story is based on materials provided by Penn State. Note: Materials may be edited for content and length.


Cite This Page:

Penn State. "Mechanical Forces Found To Exert Larger Role In Blood Vessel Health And Disease." ScienceDaily. ScienceDaily, 23 July 1999. <www.sciencedaily.com/releases/1999/07/990723083451.htm>.
Penn State. (1999, July 23). Mechanical Forces Found To Exert Larger Role In Blood Vessel Health And Disease. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/1999/07/990723083451.htm
Penn State. "Mechanical Forces Found To Exert Larger Role In Blood Vessel Health And Disease." ScienceDaily. www.sciencedaily.com/releases/1999/07/990723083451.htm (accessed September 16, 2014).

Share This



More Health & Medicine News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

President To Send 3,000 Military Personnel To Fight Ebola

President To Send 3,000 Military Personnel To Fight Ebola

Newsy (Sep. 16, 2014) President Obama is expected to send 3,000 troops to West Africa as part of the effort to contain Ebola's spread. Video provided by Newsy
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

AFP (Sep. 16, 2014) Since the arrival of Ebola in Ivory Coast, Ivorians have been abandoning their pets, particularly monkeys, in the fear that they may transmit the virus. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Study Links Male-Pattern Baldness To Prostate Cancer

Study Links Male-Pattern Baldness To Prostate Cancer

Newsy (Sep. 16, 2014) New findings suggest men with a certain type of baldness at age 45 are 39 percent more likely to develop aggressive prostate cancer. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

      Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins