Liposomal Nanocarriers of Preassembled Glycocalyx Restore Venular Permeability in Sepsis: Assessed Quantitatively with a Novel Microchamber System

Background: The endothelial glycocalyx (EG), covering the luminal side of endothelial cells, regulates vascular permeability and senses wall shear stress. In sepsis, EG undergoes degradation leading to increased permeability and edema formation. We hypothesized that restoring EG integrity using liposomal nanocarriers of preassembled glycocalyx (LNPG) will restore normal venular permeability in a lipopolysaccharide (LPS)-induced sepsis model of mice. Methods: To test this hypothesis, we designed a unique perfusion microchamber in which the vascular permeability of isolated and cannulated mice mesenteric venules could be assessed by measuring the concentration of Evans blue dye (EBD) by fluorescent spectroscopy in microliter-samples of extravascular solution (ES). Results: Histamine-induced time- and dose-dependent increases in EBD in the ES could be measured, confirming the sensitivity of the microchamber system. Notably, the histamine-induced increase in permeability was significantly attenuated by histamine receptor (H1) antagonist, triprolidine hydrochloride. Subsequently, mice were treated with LPS, or LPS + LNPG. Compared to control mice, venules from LPS-treated mice showed a significant increased permeability, which was significantly reduced by LNPG administration. Moreover, in the presence of wall shear stress, intraluminal administration of LNPG significantly reduced the permeability in isolated venules from LPS-treated mice. Conclusion: Our newly developed microchamber system can quantitatively measure the permeability of isolated venules. LPS-induced sepsis increases permeability of venules that is attenuated by in vivo LNPG administration, which is also reestablished endothelial vasomotor responses to shear stress. Thus, LNPG presents a promising therapeutic potential for restoring EG function and thereby mitigating the increased permeability in sepsis. Support: National Institute of Health [grant number: HL144528, Dong Sun] and the Uehara Memorial Foundation [grant number: 202241049, Shinya Ishiko) and Hungarian Academy of Sciences Post-Covid 2021-34 (AK) and MIT of Hungary, National Research, Development, and Innovation Fund, OTKA K 132596 (AK). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.