Bubble-Induced Endothelial Microparticles Promote Endothelial Dysfunction

Abstract

Decompression sickness is a systemic pathophysiological process caused by bubbles and endothelial microparticles (EMPs) are established markers reflecting competency of endothelial function and vascular biology. Here, we investigated the effects of bubble-induced EMPs on endothelial cells in vitro and vivo. Rat pulmonary microvascular endothelial cells (PMVECs) were isolated and stimulated by bubbles and bubble-induced EMPs were collected and incubated with normal PMVECs in vitro. Cell viability and apoptosis were detected using Cell Counting Kit-8 assay and Annexin V FITC/PI double staining, respectively. Cell permeability and pro-inflammatory cytokines were determined by electric cell substrate impedance sensing and enzyme-linked immunosorbent assay, respectively. Intracellular nitric oxide and reactive oxygen species production were analyzed microscopically. In vivo study, bubble-induced EMPs were intravenously injected to the rats and soluble thrombomodulin, intercellular adhesion molecule 1, and vascullar adhesion molecule 1 were involved in evaluating endothelial dysfunction. In our study, bubble stimulus resulted in a significant increase of EMPs release by 3 fold. Bubble-induced EMPs significantly decreased cell viability and increased cell apoptosis. Moreover, bubble-induced EMPs induced abnormal increase of cell permeability and over-expression of pro-inflammatory cytokines. Intracellular ROS production increased while NO production decreased. These negative effects caused by bubble-induced EMPs were remarkably suppressed when EMPs pretreated with surfactant FSN-100. Finally, intravenous injection of bubble-induced EMPs caused elevations of soluble thrombomodulin and pro-inflammatory cytokines in the circulation. Altogether, our results demonstrated that bubble-induced EMPs can mediate endothelial dysfunction in vitro and vivo, which can be attenuated by EMPs abatement strategy. These data expanded our horizon of the detrimental effects of bubble-induced EMPs, which may be of great concern in DCS.

Bubbles Induce Endothelial Microparticle Formation via a Calcium-Dependent Pathway Involving Flippase Inactivation and Rho Kinase Activation

“…The endothelium plays a key role in response to bubble contact, which convert it from inactivated to activated condition, resulting in endothelial dysfunction and mediating deleterious effects upon the surrounding tissues. Previous studies demonstrated that bubble contact promoted MPs formation, which further facilitated endothelial dysfunction [25-27, 30]. An illustration of the mechanisms involved in bubble-induced EMPs formation is meaningful because it may provide an innovative perspective for preventing adverse effects of bubble-induced EMPs.…”

“…HUVECs were then subjected to 30 min of bubble contact as previously described and non-treated cells were used as controls. In brief, half of one milliliter nitrogen (N 2 ) was injected to CO 2 -independent medium and the device was put into a 37 °C shaking table so that bubbles were allowed to contact with the confluent cells [30]. Six hours after bubble stimulus, the cultural medium was collected and cleared of cells and cell debris by centrifugation at 1500 g for 15 min at 4℃.…”

Vascular dysfunction following breath-hold diving

“…Bubble-induced MPs may only occupy a section of all MPs after DCS. Other factors such as an inflammatory response may also activate the endothelium and subsequently induce MP release (Yu et al 2017).…”

Nanobubbles Form at Active Hydrophobic Spots on the Luminal Aspect of Blood Vessels: Consequences for Decompression Illness in Diving and Possible Implications for Autoimmune Disease—An Overview

“…Mitochondrial dysfunction is likely a key contributor to the pathophysiology of DCI. Bubble contact with endothelial cells released microparticles which decreased cell viability, increased apoptosis, and caused over-expression of pro-inflammatory cytokines (Yu et al, 2017 ). Protection of the endothelium with escin (the main active compound in horse chestnut seed extract) reduced the incidence of DCI in the rat (Zhang et al, 2017a ).…”