High-pressure treated cartilage and fascia grafts for tissue defect reconstruction in head and neck surgery: In vitro characterisation of cell vitality, morphology and biomechanics

Despite advances in tissue engineering, allografts remain the most commonly used biomaterial in head and neck reconstructive surgery. However, conventional allograft processing (radiation, solvent treatment, freeze-drying) is invasive and deteriorates the extracellular matrix (ECM) and the biomechanical properties. In contrast, high hydrostatic pressure (HHP) treatment was shown to devitalise bone and articular cartilage preserving the biomechanically stable ECM. This study investigates the impact of HHP on viability, ECM structure and biomechanics of fascia lata, septal and thyroid cartilage.

Fascia lata and cartilage (human/rabbit) were treated with 150 and 300 MPa HHP for 10 min. Afterwards, the devitalisation was analysed by WST-1 assay and DNA quantification. Apoptosis and necrosis were differentiated by flow cytometry (Ax5/PI). The integrity of the ECM was evaluated using histology (HE, Safranin-O) and scanning electron microscopy. Finally, the biomechanics were assessed by compression and tensile testing.

150 MPa HHP treatment reduced cell vitality by induction of apoptosis, while 300 MPa triggered necrotic cell death and completely devitalised cartilage and fascia. However, both protocols, 150 and 300 MPa, did not deteriorate the structure of the ECM. In line with these findings, biomechanics of cartilage (e-modulus, stiffness, hardness) and fascia (tensile/yield strength) remained unchanged.

This study shows that HHP treatment causes devitalisation of fascia lata as well as septal and thyroid cartilage. As ECM proteins remain intact, HHP treated tissue may provide a biomechanically stable scaffold for tissue specific remodelling. Therefore, HHP treated allografts might be a promising approach for reconstructive head and neck surgery.

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Publication History

Article published online:
10 June 2020