Abstract
Antithrombin is a promising option for the treatment of sepsis, and vascular endothelium
is an important target for this fatal condition. Here, we aimed to evaluate the protective
effects of different glycoforms of antithrombin on histone-induced endothelial cell
damage and explore the responsible mechanisms in an experimental model in vitro. Endothelial
cells were treated in vitro using histone H4 to induce cellular damage. Various doses
of either α- or β-antithrombin were used as treatment interventions, and both cell
viability and the levels of lactate dehydrogenase (LDH) in the medium were assessed.
Endothelial cell damage was also assessed using microscopic examination and immunofluorescent
staining with anti-syndecan-4 and anti-antithrombin antibodies. As a result, both
glycoforms of antithrombin significantly improved cell viability when administered
at a physiological dose (150 μg/mL). Cellular injury as evaluated using the LDH level
was significantly suppressed by β-antithrombin at a supranormal dose (600 μg/mL).
Microscopic observation suggested that β-antithrombin suppressed the endothelial cell
damage more efficiently than α-antithrombin. β-Antithrombin suppressed the intensity
of syndecan-4 staining which became evident after treatment with histone H4, more
prominently than α-antithrombin. The distribution of antithrombin was identical to
that of syndecan-4. In conclusion, both α- and β-antithrombin can protect vascular
endothelial cells from histone H4-induced damage, although the effect was stronger
for β-antithrombin. The responsible mechanisms might involve the binding of antithrombin
to the glycocalyx on the endothelial surface. These results provide a theoretical
basis for the application of antithrombin to the prevention and treatment of sepsis-related
endothelial damage.
Keywords
antithrombin - glycoform - vascular endothelial cell - glycocalyx - syndecan-4
