Influence of endothelial glycocalyx degradation and surfactants on air embolism adhesion.
BACKGROUND
Microbubble adherence to endothelial cells is enhanced after damage to the glycocalyx. The authors tested the hypothesis that exogenous surfactants delivered intravascularly have differential effects on the rate of restoration of blood flow after heparinase-induced degradation of the endothelial glycocalyx.


METHODS
Air microbubbles were injected into the rat cremaster microcirculation after perfusion with heparinase or saline and intravascular administration of either saline or one of two surfactants. The surfactants were Pluronic F-127 (Molecular Probes, Eugene, OR) and Perftoran (OJSC SPC Perftoran, Moscow, Russia). Embolism dimensions and dynamics were observed using intravital microscopy.


RESULTS
Significant results were that bubbles embolized the largest diameter vessels after glycocalyx degradation. Bubbles embolized smaller vessels in the surfactant treatment groups. The incidence of bubble dislodgement and the magnitude of distal displacement were smallest after glycocalyx degradation alone and largest after surfactant alone. The time to bubble clearance and restoration of blood flow was longest with heparinase alone and shortest with Pluronic F-127 alone.


CONCLUSIONS
Degradation of the glycocalyx causes air bubbles to adhere to the endothelium more proximally in the arteriolar microcirculation. Surfactants added after glycocalyx degradation and before gas embolization promotes bubble lodging in the distal microcirculation. Surfactants may have a clinical role in reducing embolism bubble adhesion to endothelial cells undergoing glycocalyx disruption.
Eckmann
David M
DM
Department of Anesthesiology and Critical Care, Institute for Medicine and Engineering, The University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. eckmanndm@uphs.upenn.edu
Armstead
Stephen C
SC
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002448:Cell Adhesion / Q000187:drug effects*; D003627:Data Interpretation, Statistical; D004618:Embolism, Air / Q000473:pathology*; D042783:Endothelial Cells / Q000378:metabolism / Q000502:physiology*; D005466:Fluorocarbons / Q000494:pharmacology; D019276:Glycocalyx / Q000378:metabolism / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D019763:Heparin Lyase / Q000737:chemistry; D007700:Kinetics; D008297:Male; D009129:Muscle Tonus / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D010477:Perfusion; D020442:Poloxamer / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013501:Surface-Active Agents / Q000494:pharmacology*
D005466:Fluorocarbons; D013501:Surface-Active Agents; D020442:Poloxamer; C063334:perftoran; D019763:Heparin Lyase