Modelling inflammatory endothelial dysfunction: a human in vitro platform for translational research

Systemic inflammation presents a significant challenge to the long-term function of biohybrid implants. While endothelialisation of biohybrid implants has been shown to improve device hemocompatibility, its feasibility under the influence of patients' inflammatory status remains largely unexplored. To investigate this, we developed a controlled in vitro model which allows to study endothelial dysfunction under inflammatory stress.

Endothelial cells were cultured on polydimethylsiloxane under physiological shear stress and exposed to lipopolysaccharide (LPS)-activated peripheral blood mononuclear cells (PBMCs), mimicking systemic inflammation at the blood-material interface. Endothelial morphology and confluence was assessed using immunohistochemistry and scanning electron microscopy. Leukocyte adhesion was evaluated directly as well as indirectly, using flow cytometry to analyse cell adhesion molecules. Quantitative PCR was used for gene expression analysis of inflammatory mediators.

Notably, neither LPS nor PBMCs alone induced endothelial disruption under shear stress, whereas their combination significantly impaired endothelial confluence. Inflammatory activation led to substantial loss of endothelial confluence, increased leukocyte adhesion, and elevated expression of adhesion molecules ICAM-1, VCAM-1, and E-selectin. Gene expression analysis further highlighted the upregulation of inflammatory mediators, such as IL-6, IL-8, IL-10, and MCP-1.

This study underscores the challenges of implementing endothelialisation in biohybrid devices, particularly in patients with systemic inflammation. By considering translational hurdles, this work contributes to the development of clinically viable biohybrid constructs and highlights the importance of considering inflammatory dynamics when designing next-generation implants.