Changes in endothelial cell proliferation and vascular permeability after systemic lipopolysaccharide administration in the subfornical organ

• The subfornical organ has highly permeable and angiogenic vasculature.
• Endothelial cell proliferation and PV-1 immunoreactivity was decreased after systemic lipopolysaccharide administration.
• Systemic bacterial lipopolysaccharide administration decreased the vascular permeability.

The subfornical organ (SFO) has highly permeable fenestrated vasculature and is a key site for immune-to-brain communications. Recently, we showed the occurrence of continuous angiogenesis in the SFO. In the present study, we found that systemic administration of bacterial lipopolysaccharide (LPS) reduced the vascular permeability and endothelial cell proliferation. In LPS-administered mice, the SFO vasculature showed a significant decrease in the immunoreactivity of plasmalemma vesicle associated protein-1, a marker of endothelial fenestral diaphragms. These data suggest that vasculature undergoes structural change to decrease vascular permeability in response to systemic LPS administration.