Towards Biohybrid Lung Development: Establishment of a Porcine In Vitro Model

Lung transplantation (LTx) is the only curative therapy option for patients with end-stage lung diseases, though only available for chosen patients. To provide an alternative treatment option to LTx, we aim for the development of an implantable biohybrid lung (BHL) based on hollow fiber membrane (HFM) technology used in extracorporeal membrane oxygenators. Crucial for long-lasting BHL durability is complete hemocompatibility of all blood contacting surfaces, which can be achieved by their endothelialization. In continuation to successful in vitro investigations using human endothelial cells (ECs), indicating general feasibility, the appropriate porcine in vivo model needs to be prepared and established to fill the translational data gap prior to patient's application. Therefore, isolation of porcine ECs from carotid arteries (pCECs) was established. Following, pCECs were used for HFM endothelialization and examined under static and dynamic conditions using cell medium or heparinized blood, to assess their proliferation capacity, flow resistance and activation state, especially under clinically relevant conditions. Additionally, comparative hemocompatibility tests between native and endothelialized HFMs were performed. Overall, pure pCECs formed a viable and confluent monolayer, which resisted applied flow conditions, in particular due to physiological extracellular matrix synthesis. Additionally, pCECs remained the non-inflammatory and anti-thrombogenic status, significantly improving the hemocompatibility of endothelialized HFMs. Finally, as relevant for reliable porcine to human translation, pCECs behaved in the same way as human ECs. Concluding, generated in vitro data justify further steps towards pre-clinical BHL examination, in particular BHL application to porcine lung injury models, reflecting the clinical scenario with end-stage lung-diseased patients.

Automated summary

Lung transplantation is the only curative therapy for end-stage lung diseases, but it is limited to selected patients. Researchers have developed an implantable biohybrid lung based on hollow fiber membrane technology to provide an alternative treatment option. The hemocompatibility of the lung's blood contacting surfaces, achieved through endothelialization, is crucial for its durability. In vitro investigations using human endothelial cells have shown feasibility, and now the appropriate porcine in vivo model needs to be established to bridge the translational gap. The isolated porcine endothelial cells from carotid arteries have been used for endothelialization and demonstrated good viability, resistance to flow conditions, and improved hemocompatibility. The behavior of the porcine endothelial cells is comparable to human endothelial cells, supporting the further examination of the biohybrid lung in pre-clinical studies using porcine lung injury models.