Decellularized Aortic Valve Tissue Induces Inflammatory Chemokine/Cytokine Secretion of Smooth Muscle Cells

Background: Decellularized extracellular matrix (dECM) is increasingly being used as a platform for cardiovascular implants, with first applications—such as decellularized heart valves—showing very promising clinical results. Smooth muscle cells (SMC) are typically involved in the recellularization of dECM in vivo, while also being known for their phenotypic plasticity depending on the surrounding environmental cues. Still, not much is known of the influence of dECM on the SMC phenotype as well as their role in the immune-mediated structural and functional integration or degeneration of dECM based implants in vivo. Therefore, here we investigated the influence of decellularized aortic valve tissue on SMCs with regards to inflammatory activation.

Method: Aortic SMCs were isolated from adult Wistar rats and were cultured together with decellularized ovine aortic valve tissue (davECM) in a 96-well plate based high throughput setup for up to 72 hours. Cell-matrix interaction was assessed by confocal microscopy. SMCs cultured without davECM and polarized with LPS or IL-4 served as controls. Supernatant of cell culture media after 6, 24, 48, and 72 hours of SMCs–davECM cultures as well as controls were analyzed for secreted chemokines/cytokines via multiplex-ELISA using an inflammatory panel.

Results: Confocal microscopy revealed SMC migration and attachment to the davECM. SMCs cultured alone showed almost no secretion of inflammatory chemokines/cytokines within the first 72 hours. However, when cultured together with davECM SMCS showed significant secretion of CXCL1, CCL2, TNF-α, IL-17A, and IL-6, especially after 48 and 72 hours. Activation of inflammatory chemokine/cytokine secretion of davECM-SMCs was higher than compared with LPS or IL-4 polarized SMCs, who only led to secretion of CXCL1, CCL2, and IL-6, but in much lower concentrations.

Conclusion: Decellularized aortic valve ECM stimulates inflammatory chemokine/cytokine secretion of SMCs in vitro. This suggests that SMCs may have a role in dECM-mediated inflammatory response possibly even triggering implant degeneration. Further investigations are needed to elucidate on how dECM may induce a SMC phenotype switch and the underlying molecular mechanisms, as this could help better understand the immune-mediated implant degeneration and reveal new therapeutic targets.

Publication History

Article published online:
28 January 2023