Open AccessEffects of circulating extracellular microvesicles from spinal cord-injured adults on endothelial cell function
Author(s) -
L. Madden Brewster,
Geoff B. Coombs,
Vinicius P Garcia,
Jamie G. Hijmans,
Noah M DeSouza,
Kelly A. Stockelman,
Otto Barak,
Tanja Mijačika,
Željko Dujić,
Jared J. Greiner,
Aaron A. Phillips,
Philip N. Ainslie,
Christopher A. DeSouza
Publication year - 2020
Publication title -
clinical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.91
H-Index - 138
eISSN - 1470-8736
pISSN - 0143-5221
DOI - 10.1042/cs20200047
Subject(s) - microvesicles , enos , medicine , oxidative stress , inflammation , endocrinology , endothelial dysfunction , immunology , nitric oxide , nitric oxide synthase , biology , microrna , biochemistry , gene
People with spinal cord injury (SCI) have three- to four-fold greater risk of cardiovascular disease (CVD) compared with those without SCI. Although circulating extracellular microvesicles are key effectors of vascular health and disease, how their functional phenotype might be altered with SCI is unknown. The aim of the present study was to determine the effects of microvesicles isolated from SCI adults on endothelial cell inflammation and oxidative stress as well as endothelial nitric oxide (NO) synthase (eNOS) activation and tissue-type plasminogen activator (t-PA) expression. Eighteen young and middle-aged adults were studied: 10 uninjured (7M/3F; age: 39 ± 3 years) and 8 cervical level spinal cord injured (SCI; 7M/1F; 46 ± 4 years; cervical injury: C3: n=1; C5: n=4; C6: n=3). Circulating microvesicles were isolated, enumerated and collected from plasma by flow cytometry. Human umbilical vein endothelial cells (HUVECs) were cultured and treated with microvesicles from either the uninjured or SCI adults. Microvesicles from SCI adults did not affect cellular markers or mediators of inflammation and oxidative stress. However, microvesicles from the SCI adults significantly blunted eNOS activation, NO bioavailability and t-PA production. Intercellular expression of phosphorylated eNOS at Ser1177 and Thr495 sites, specifically, were ∼65% lower and ∼85% higher, respectively, in cells treated with microvesicles from SCI compared with uninjured adults. Decreased eNOS activity and NO production as well as impaired t-PA bioavailability renders the vascular endothelium highly susceptible to atherosclerosis and thrombosis. Thus, circulating microvesicles may contribute to the increased risk of vascular disease and thrombotic events associated with SCI.