Use of platelet lysate for bone regeneration - are we ready for clinical translation?

Abstract

Current techniques to improve bone regeneration following trauma or tumour resection involve the use of autograft bone or its substitutes supplemented with osteoinductive growth factors and/or osteogenic cells such as mesenchymal stem cells (MSCs). Although MSCs are most commonly grown in media containing fetal calf serum, human platelet lysate (PL) offers an effective alternative. Bone marrow - derived MSCs grown in PL-containing media display faster proliferation whilst maintaining good osteogenic differentiation capacity. Limited pre-clinical investigations using PL-expanded MSCs seeded onto osteoconductive scaffolds indicate good potential of such constructs to repair bone in vivo. In an alternative approach, nude PL-coated scaffolds without seeded MSCs have been proposed as novel regenerative medicine devices. Even though methods to coat scaffolds with PL vary, in vitro studies suggest that PL allows for MSC adhesion, migration and differentiation inside these scaffolds. Increased new bone formation and vascularisation in comparison to uncoated scaffolds have also been observed in vivo. This review outlines the state-of-the-art research in the field of PL for ex vivo MSC expansion and in vivo bone regeneration. To minimise inconsistency between the studies, further work is required towards standardisation of PL preparation in terms of the starting material, platelet concentration, leukocyte depletion, and the method of platelet lysis. PL quality control procedures and its “potency” assessment are urgently needed, which could include measurements of key growth and attachment factors important for MSC maintenance and differentiation. Furthermore, different PL formulations could be tailor-made for specific bone repair indications. Such measures would undoubtedly speed up clinical translation of PL-based treatments for bone regeneration.

Keywords: Mesenchymal stem cells, Platelet lysate, Bone regeneration

Core tip: Human platelet lysate (PL) offers an exciting opportunity for expanding mesenchymal stem cells (MSCs), as well as for use in bone regeneration as a scaffold coating. In this review, we describe the state-of-the-art research in the area of bone regeneration utilising PL and MSCs and emphasise the need for standardisation of PL preparation and its quality control in order to progress further in this exciting area of research. Different PL formulations could be tailor-made for specific scaffolds and bone repair indications, both in autologous and allogenic settings. More pre-clinical and clinical work is needed to progress this research into clinical translation.