NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Intracellular pH changes in human aortic smooth muscle cells in response to fluid shear stressThe smooth muscle cell (SMC) layers of human arteries may be exposed to blood flow after endothelium denudation, for example, following balloon angioplasty treatment. These SMCs are also constantly subjected to pressure driven transmural fluid flow. Flow-induced shear stress can alter SMC growth and metabolism. Signal transduction mechanisms involved in these flow effects on SMCs are still poorly understood. In this work, the hypothesis that shear stress alters the intracellular pH (pHi) of SMC is examined. When exposed to venous and arterial levels of shear stress, human aortic smooth muscle cells (hASMC) undergo alkalinization. The alkalinization plateau persisted even after 20 min of cell exposure to flow. Addition of amiloride (10 micromoles) or its 5-(N-ethyl-N-isopropyl) analog (EIPA, 10 micromoles), both Na+/H+ exchanger inhibitors, attenuated intracellular alkalinization, suggesting the involvement of the Na+/H+ exchanger in this response. The same concentrations of these inhibitors did not show an effect on pHi of hASMCs in static culture. 4-Acetamido-4'-isothio-cyanatostilbene-2,2'-disulfonic acid (SITS, 1 mM), a Cl-/HCO3- exchange inhibitor, affected the pHi of hASMCs both in static and flow conditions. Our results suggest that flow may perturb the Na+/H+ exchanger leading to an alkalinization of hASMCs, a different response from the flow-induced acidification seen with endothelial cells at the same levels of shear stress. Understanding the flow-induced signal transduction pathways in the vascular cells is of great importance in the tissue engineering of vascular grafts. In the case of SMCs, the involvement of pHi changes in nitric oxide production and proliferation regulation highlights further the significance of such studies.
Document ID
20040088789
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Stamatas, G. N.
(Institute of Biosciences and Bioengineering, Rice University Houston, Texas 77251-1892, United States)
Patrick, C. W. Jr
McIntire, L. V.
Date Acquired
August 21, 2013
Publication Date
December 1, 1997
Publication Information
Publication: Tissue engineering
Volume: 3
Issue: 4
ISSN: 1076-3279
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: R37-HL-18672
CONTRACT_GRANT: NAGW-5007
CONTRACT_GRANT: P01-NS-22237
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Cell Biology
Non-NASA Center

Available Downloads

There are no available downloads for this record.
No Preview Available