Soluble extracts from amnion and chorion membranes improve hMSC osteogenic response in a mineralized collagen scaffold

Abstract

Craniomaxillofacial (CMF) bone injuries present a major surgical challenge and cannot heal naturally due to their large size and complex topography. Approximately 26% of injured Iraq war veterans sustained CMF injuries in the form of blast wounds, and 0.1% of births involve CMF defects like cleft palate. We previously developed a class of mineralized collagen scaffolds designed to mimic native extracellular matrix (ECM) features of bone. These scaffolds induce in vitro human mesenchymal stem cell (hMSC) osteogenic differentiation and in vivo bone formation without the need for exogenous osteogenic supplements. Here, we seek to enhance cellular bioactivity and osteogenic activity via inclusion of placental-derived products in the scaffold architecture. The amnion and chorion membranes are distinct components of the placenta that individually have displayed anti-inflammatory, immunogenic, and osteogenic properties. They represent a potentially powerful compositional modification to the mineralized collagen scaffolds to improve bioactivity. Here we examine introduction of the placental-derived amnion and chorion membranes or soluble extracts derived from these membranes into the collagen scaffolds, comparing the potential for these modifications to improve hMSC osteogenic activity. We report structural analysis of the scaffolds via mechanical compression testing, imaging via scanning electron microscopy (SEM), and assessments of various metrics for osteogenesis including gene expression (Nanostring), protein elution (ELISA), alkaline phosphatase (ALP) activity, inductively coupled plasma mass spectrometry (ICP) for mineralization, and cell viability (AlamarBlue). Notably, a post fabrication step to incorporate soluble extracts from the amnion membrane induces the highest levels of metabolic activity and performs similarly to the conventional mineralized collagen scaffolds in regard to mineral deposition and elution of the osteoclast inhibitor osteoprotegerin (OPG). Together, these findings suggest that mineralized collagen scaffolds modified using elements derived from amnion and chorion membranes, particularly their soluble extracts, represent a promising environment conducive to craniomaxillofacial bone repair.