title: Plasma from human volunteers subjected to remote ischemic preconditioning protects human endothelial cells from hypoxia-induced cell damage.
abstract: Short repeated cycles of peripheral ischemia/reperfusion (I/R) can protect distant organs from subsequent prolonged I/R injury; a phenomenon known as remote ischemic preconditioning (RIPC). A RIPC-mediated release of humoral factors might play a key role in this protection and vascular endothelial cells are potential targets for these secreted factors. In the present study, RIPC-plasma obtained from healthy male volunteers was tested for its ability to protect human umbilical endothelial cells (HUVEC) from hypoxia-induced cell damage. 10 healthy male volunteers were subjected to a RIPC-protocol consisting of 4 × 5 min inflation/deflation of a blood pressure cuff located at the upper arm. Plasma was collected before (T0; control), directly after (T1) and 1 h after (T2) the RIPC procedure. HUVEC were subjected to 24 h hypoxia damage and simultaneously incubated with 5% of the respective RIPC-plasma. Cell damage was evaluated by lactate dehydrogenase (LDH)-measurements. Western blot experiments of hypoxia inducible factor 1 alpha (HIF1alpha), phosphorylated signal transducer and activator of transcription 5 (STAT5), protein kinase B (AKT) and extracellular signal-related kinase 1/2 (ERK-1/2) were performed. Furthermore, the concentrations of hVEGF were evaluated in the RIPC-plasma by sandwich ELISA. Hypoxia-induced cell damage was significantly reduced by plasma T1 (p = 0.02 vs T0). The protective effect of plasma T1 was accompanied by an augmentation of the intracellular HIF1alpha (p = 0.01 vs T0) and increased phosphorylation of ERK-1/2 (p = 0.03 vs T0). Phosphorylation of AKT and STAT5 remained unchanged. Analysis of the protective RIPC-plasma T1 showed significantly reduced levels of hVEGF (p = 0.01 vs T0). RIPC plasma protects endothelial cells from hypoxia-induced cell damage and humoral mediators as well as intracellular HIF1alpha may be involved.
authors.affiliation: Laboratory of Experimental Intensive Care and Anaesthesiology (L.E.I.C.A.), Department of Anaesthesiology, University of Amsterdam, Academic Medical Centre (AMC), Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands, N.C.Hauck@amc.uva.nl.
authors.forename: Nina C
authors.initials: NC
authors.lastname: Weber
authors.forename: Isabelle
authors.initials: I
authors.lastname: Riedemann
authors.forename: Kirsten F
authors.initials: KF
authors.lastname: Smit
authors.forename: Karina
authors.initials: K
authors.lastname: Zitta
authors.forename: Djai
authors.initials: D
authors.lastname: van de Vondervoort
authors.forename: Coert J
authors.initials: CJ
authors.lastname: Zuurbier
authors.forename: Markus W
authors.initials: MW
authors.lastname: Hollmann
authors.forename: Benedikt
authors.initials: B
authors.lastname: Preckel
authors.forename: Martin
authors.initials: M
authors.lastname: Albrecht
mesh_terms: D000328:Adult; D015153:Blotting, Western; D015687:Cell Hypoxia / Q000502:physiology*; D042783:Endothelial Cells / Q000473:pathology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods; D008297:Male; D010949:Plasma / Q000737:chemistry / Q000502:physiology*; D015427:Reperfusion Injury / Q000517:prevention & control; D055815:Young Adult