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Oxidative Medicine and Cellular Longevity
Volume 2, Issue 1, Pages 2-6
http://dx.doi.org/10.4161/oxim.2.1.7611

Hypoxia Mediated Release of Endothelial Microparticles and Increased Association of S100A12 with Circulating Neutrophils

1Department of Sport, Health and Exercise Science, University of Hull, Hull, United Kingdom
2Postgraduate Medical Institute, University of Hull, Hull, United Kingdom
3Postgraduate Medical Institute, Room 003, Hardy Building, University of Hull, Hull, HU6 7RX, United Kingdom

Received 28 November 2008; Revised 10 December 2008; Accepted 11 December 2008

Copyright © 2009 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Microparticles are released from the endothelium under normal homeostatic conditions and have been shown elevated in disease states, most notably those characterised by endothelial dysfunction. The endothelium is sensitive to oxidative stress/status and vascular cell adhesion molecule-1 (VCAM-1) expression is upregulated upon activated endothelium, furthermore the presence of VCAM-1 on microparticles is known. S100A12, a calcium binding protein part of the S100 family, is shown to be present on circulating leukocytes and is thought a sensitive marker to local inflammatory process, which may be driven by oxidative stress. Eight healthy males were subjected to breathing hypoxic air (15% O2, approximately equivalent to 3000 metres altitude) for 80 minutes in a temperature controlled laboratory and venous blood samples were processed immediately for VCAM-1 microparticles (VCAM-1 MP) and S100A12 association with leukocytes by flow cytometry. A pre-hypoxic blood sample was used for comparison. Both VCAM-1 MP and S100A12 association with neutrophils were significantly elevated post hypoxic breathing later declining to levels observed in the pre-test samples. A similar trend was observed in both cases and a correlation may exist between these two markers in response to hypoxia. These data offer evidence using novel markers of endothelial and circulating blood responses to hypoxia.