Hemorrhagic Shock and Resuscitation Causes Glycocalyx Shedding and Endothelial Oxidative Stress Preferentially in the Lung and Intestinal Vasculature

Abstract

Hemorrhagic shock has recently been shown to cause shedding of a carbohydrate surface layer of endothelial cells known as the glycocalyx. This shedding of the glycocalyx is thought to be a mediator of the coagulopathy seen in trauma patients. Clinical studies have demonstrated increases in shed glycocalyx in the blood after trauma, and animal studies have measured glycocalyx disruption in blood vessels in the lung, skeletal muscle, and mesentery. However, no study has measured glycocalyx disruption across a wide range of vascular beds to quantify the primary locations of this shedding. Methods: In the present study, we used a rat model of hemorrhagic shock and resuscitation to more comprehensively assess glycocalyx disruption across a range of organs. Glycocalyx disruption was assessed by fluorescent-labeled wheat germ agglutinin or syndecan-1 antibody staining in flash frozen tissue. Results: We found that our model did elicit glycocalyx shedding, as assessed by an increase in plasma syndecan-1 levels. In tissue sections, we found that the greatest glycocalyx disruption occurred in vessels in the lung and intestine. Shedding to a lesser extent was observed in vessels of the brain, heart, and skeletal muscle. Liver vessel glycocalyx was unaffected, and kidney vessels, including the glomerular capillaries, displayed an increase in glycocalyx. We also measured reactive oxygen species (ROS) in the endothelial cells from these organs, and found that the greatest increase in ROS occurred in the two beds with the greatest glycocalyx shedding, the lungs, and intestine. We also detected fibrin deposition in lung vessels following hemorrhage-resuscitation. Conclusions: We conclude that the endothelium in the lungs and intestine are particularly susceptible to the oxidative stress of hemorrhage-resuscitation, as well as the resulting glycocalyx disruption. Thus, these two vessel beds may be important drivers of coagulopathy in trauma patients.

Dimethyl malonate slows succinate accumulation and preserves cardiac function in a swine model of hemorrhagic shock

“…15,45 Our previous work has shown that the vasculature in the lung are disproportionately exposed to ROS after ischemia-reperfusion and are most vulnerable to glycocalyx injury. 21 The present study confirmed that DMM protects the glycocalyx in the lung. This protective effect was seen in both large and small vessels, as DMM protected the glycocalyx in the pulmonary artery and the capillary vessels in the alveoli.…”

“…Glycocalyx staining was performed to determine staining intensity of the endothelial glycocalyx as previously described. We performed these experiments because our prior work has shown that the endothelial glycocalyx in lung tissue is preferentially affected in HS 21 . Briefly, flash frozen tissue was sectioned in a cryostat at −20°C at a section thickness of 10 μm, and the sections were affixed to room temperature glass slides.…”

“…We performed these experiments because our prior work has shown that the endothelial glycocalyx in lung tissue is preferentially affected in HS. 21 Briefly, flash frozen tissue was sectioned in a cryostat at −20°C at a section thickness of 10 μm, and the sections were affixed to room temperature glass slides. Fixation was performed by immersion in 4°C methanol for 10 minutes.…”

“…[15][16][17][18][19][20] Our laboratory's previous work has shown that the lungs are preferentially damaged by oxidative stress after HS and resuscitation. 21 Dimethyl malonate (DMM) is a cell permeable, competitive inhibitor of SI dehydrogenase and has been shown to reduce SI levels. 22 Succinate dehydrogenase is an enzyme complex that converts fumarate to SI during anaerobic metabolism, where the citric acid cycle is reversed.…”

Targeting repair of the vascular endothelium and glycocalyx after traumatic injury with plasma and platelet resuscitation

“…While shedding of the endothelial glycocalyx is thought to affect the systemic vascular endothelium as the glycocalyx is ubiquitous, there may be organ-based differences. Recently Abdullah et al [55] evaluated glycocalyx shedding after hemorrhagic shock in a rat model by staining multiple organs with a syndecan-1 antibody. This demonstrated that the greatest glycocalyx disruption occurred in the vasculature of the lungs and intestine, where the highest levels of endothelial reactive oxygen species were also measured, and shedding to a lesser extent occurred in the brain, heart, and skeletal muscle.…”