Abstract
Vasculitis is an inflammatory condition characterized by immune cell activation and vascular endothelial dysfunction leading to severe clinical complications, including cytokine release syndrome. Despite existing treatment strategies such as corticosteroids and NSAIDs, severe cases remain difficult to manage, necessitating improved in vitro models for mechanistic studies and drug evaluation. This study established a direct coculture model of human umbilical vein endothelial cells (HUVECs) and peripheral blood mononuclear cells to investigate immune-endothelial cell interactions under lipopolysaccharide (LPS)-induced inflammatory conditions. Upon LPS stimulation, the cocultured HUVECs exhibited increased expression of inflammatory cytokines (IL-6 and IL-8) and adhesion molecules (VCAM-1 and ICAM-1), along with reduced CD31 level, indicating endothelial barrier disruption. Vascular permeability assays confirmed that the coculture model exacerbated permeability changes beyond those observed in monocultures, highlighting the synergistic inflammatory effects mediated by immune-endothelial cell interactions. Furthermore, cytokine secretion analysis demonstrated that coculture conditions significantly amplified IL-6, IL-8, and TNF-α expression, mimicking the inflammatory milieu observed in vasculitis. Treatment with tocilizumab, an IL-6 receptor antagonist, effectively suppressed cytokine release and restored endothelial integrity, highlighting the potential of this model for therapeutic screening. This study provides a physiologically relevant in vitro platform for investigating the mechanisms of drug-induced and immune-mediated vasculitis with potential applications in preclinical safety assessments of biotherapeutics.