• Michelle Trieu, Matijs van Meurs, Anoek L I van Leeuwen, Van Slyke Paul P, Van Hoang, Geeraedts Leo M G LMG Jr, Christa Boer, and Charissa E van den Brom.
• From the Departments of Anesthesiology (M.T., A.L.I.v.L., C.B., C.E.v.d.B.), Physiology (M.T., A.L.I.v.L., C.E.v.d.B.), and Trauma Surgery (L.M.G.G.), VU University Medical Center, Amsterdam, The Netherlands; Departments of Pathology and Medical Biology (M.v.M.) and Critical Care (M.v.M.), University Medical Center Groningen, Groningen, The Netherlands; and Vasomune Therapeutics, Toronto, Ontario, Canada (P.V.S., V.H.).
• Anesthesiology. 2018 Feb 1; 128 (2): 361-374.

BackgroundMicrocirculatory dysfunction is associated with multiple organ failure and unfavorable patient outcome. We investigated whether therapeutically targeting the endothelial angiopoietin/Tie2 system preserves microvascular integrity during hemorrhagic shock.MethodsRats were treated with the angiopoietin-1 mimetic vasculotide and subjected to hemorrhagic shock and fluid resuscitation. Microcirculatory perfusion and leakage were assessed with intravital microscopy (n = 7 per group) and Evans blue dye extravasation (n = 8 per group), respectively. The angiopoietin/Tie2 system was studied at protein and RNA level in plasma, kidneys, and lungs.ResultsHemorrhagic shock significantly reduced continuously perfused capillaries (7 ± 2 vs. 11 ± 2) and increased nonperfused vessels (9 ± 3 vs. 5 ± 2) during hemorrhagic shock, which could not be restored by fluid resuscitation. Hemorrhagic shock increased circulating angiopoietin-2 and soluble Tie2 significantly, which associated with microcirculatory perfusion disturbances. Hemorrhagic shock significantly decreased Tie2 gene expression in kidneys and lungs and induced microvascular leakage in kidneys (19.7 ± 11.3 vs. 5.2 ± 3.0 µg/g) and lungs (16.1 ± 7.0 vs. 8.6 ± 2.7 µg/g). Vasculotide had no effect on hemodynamics and microcirculatory perfusion during hemorrhagic shock but restored microcirculatory perfusion during fluid resuscitation. Interestingly, vasculotide attenuated microvascular leakage in lungs (10.1 ± 3.3 µg/g) and significantly reduced the required amount of volume supplementation (1.3 ± 1.4 vs. 2.8 ± 1.5 ml). Furthermore, vasculotide posttreatment was also able to restore microcirculatory perfusion during fluid resuscitation.ConclusionsTargeting Tie2 restored microvascular leakage and microcirculatory perfusion and reduced fluid resuscitation requirements in an experimental model of hemorrhagic shock. Therefore, the angiopoietin/Tie2 system seems to be a promising target in restoring microvascular integrity and may reduce organ failure during hemorrhagic shock.

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