Platelet Rich Plasma Enhances The Delivery Of Adipose Tissue On 3d-printed Polycaprolactone Scaffolds For Breast Tissue Engineering
Michelle Griffin, MBChB MRes MSc MRCS PhD, Edward Donnely, MBChB MRCS MSc, Peter Butler, MD FRCS (Plast).
University College London, London, United Kingdom.
PURPOSE: Soft tissue engineering holds great promise for the restoration of breast defects by the combination of biocompatible scaffolds and growth factors. To date, there is no optimal biomaterial by which to deliver adipose tissue within a scaffold. Polycaprolactone (PCL) scaffolds are medical grade biodegradable biomaterials that offer great potential for breast tissue engineering due to its ability to be 3D-printed according to patient specific defects. Platelet Rich Plasma (PRP) is a component of blood plasma that is rich in growth factors and shown to enhance adipocyte proliferation but their ability to support soft tissue formation in vivois unknown. This study aimed to investigate the optimal 3D-printed PCL scaffold architecture to support adipose tissue delivery and determine the beneficial effect of PRP.
METHODS: Breast scaffolds were designed using SolidWorks and then 3D-printed using Fused Deposition Modelling (FDM). Different PCL scaffolds porosities (20, 30, 40, 50, 60, 80%) and pore architectures (square, honeycomb and triangle) were evaluated to closely mimic human breast tissue compressive mechanical properties. The internal structure and surface architecture of the scaffolds were assessed using scanning electron microscopy (SEM). The scaffolds were further characterised including the wettability (contact angle assessment), surface chemistry (X-ray photoelectron spectroscopy) and mechanical properties (Youngs elastic modulus in compression). The biocompatibility of the 3D-printed scaffolds was assessed by differentiating 3T3-L1 adipocytes in vitroover 14 days. The adipocyte cell adhesion, proliferation, gene expression of adipogenic markers using RT-qPCR and immunocytochemistry was evaluated. Following 4 weeks of adipocyte differentiation in vitro, the optimised PCL scaffolds were seeded with 3T3-L1 adipocytes and then implanted in the dorsum of mice with and without PRP coating from donor mice for 6 and 12 weeks. The integration, vascularisation and adipocyte formation were assessed at 12 weeks using histology and immunohistochemistry.
PCL scaffolds with 40% porosity and square pores demonstrated similar compressive properties to human breast tissue. Surface hydrophobicity and chemistry was significantly affected by porosity and pore architecture (p < 0.05). The PCL scaffolds with 40% porosity and square pores showed the greatest adipocyte cell adhesion and proliferation over 14 days. The gene and protein expression of PPAR-γ, C/EBPαand FABP4was significantly upregulated on scaffolds with 40% porosity at 7 and 14 days (p<0.05). The PCL scaffolds with PRP coating demonstrated greater adipocyte formation, tissue integration (H&E and masons trichome staining) and vessel formation (CD31 staining) in vivoat 12 weeks than without PRP treatment (p <0.05). CONCLUSION: PRP enhances adipocyte cell proliferation and differentiation on 3D-printed PCL scaffolds. The combination of PCL scaffolds with PRP holds promise for the effective delivery of adipose tissue for breast reconstruction.
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