Frequency-dependent Response of the Vascular Endothelium to Pulsatile Shear Stress.
From: Department of Biomedical Engineering, Duke University Durham, NC 27708, USA.
American journal of physiology. Heart and circulatory physiology
- Publish Date: Jul 2007
- ISSN: 0363-6135
- Volume: 293
- Issue: 1
- Pages: H645-53
- Medium: Print
- Language: English
- Citation (JAMA): Himburg Heather A, Dowd Scot E, Friedman Morton H, et al. Frequency-dependent Response of the Vascular Endothelium to Pulsatile Shear Stress.. Am. J. Physiol. Heart Circ. Physiol. Jul 2007;293:H645-53
Abstract
As a result of the complex blood flow patterns that occur in the arterial tree, certain regions of the vessel wall experience fluctuations in shear stress that are dominated by harmonic frequencies higher than the heart rate (11). To assess whether variations in frequency affect endothelial gene expression, the gene expression patterns of cultured porcine aortic endothelium exposed to three sinusoidal waveforms (1, 2, and 3 Hz; amplitude = 15 dyn/cm(2)) and one physiological waveform were compared with the expression profiles elicited by steady flow. At each frequency, including steady flow, three levels of mean shear stress (0, 7.5, and 15 dyn/cm(2)) were used. After 24 h shear exposure, RNA was extracted for microarray analysis against 10,665 Sus scrofa oligonucleotides. A two-way ANOVA identified 232 genes of which their transcription was differentially modulated by frequency, while mean shear significantly affected the expression of approximately 3,000 genes. One-way ANOVAs showed that the number of frequency-dependent genes increased as the mean shear stress was reduced. At 1 Hz, several inflammatory transcripts were repressed relative to steady flow, including VCAM and IL-8, whereas several atheroprotective transcripts were induced. The anti-inflammatory response at 1 Hz was reversed at 2 Hz. The proinflammatory response evoked by the higher frequency was most pronounced under reversing and oscillatory shear. This study suggests that arterial regions subject to both shear reversal and dominant frequencies that exceed the normal heart rate are at greater risk for atherosclerotic lesion development.
Mesh Headings (Keywords): Animals, Aorta, Biological Clocks, Blood Flow Velocity, Blood Pressure, Cells, Cultured, Endothelial Cells, Gene Expression Regulation, Mechanotransduction, Cellular, Proteome, Pulsatile Flow, Shear Strength, Swine
Check for Full Text / PubMed Unique Identifier (PMID): 17322417
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.