J Biomed Mater Res A. 2018 Apr 6. doi: 10.1002/jbm.a.36430. [Epub ahead of print]

A canine in vitro model for evaluation of marrow-derived mesenchymal stromal cell-based bone scaffolds.

Gharat TP¹, Diaz-Rodriguez P², Erndt-Marino JD², Jimenez Vergara AC², Munoz Pinto DJ², Bearden RN³, Huggins SS³, Grunlan M⁴, Saunders WB³, Hahn MS².

Abstract

Tissue engineered bone grafts based on bone marrow mesenchymal stromal cells (MSCs) are being actively developed for craniomaxillofacial (CMF) applications. As for all tissue engineered implants, the bone-regenerating capacity of these MSC-based grafts must first be evaluated in animal models prior to human trials. Canine models have traditionally resulted in improved clinical translation of CMF grafts relative to other animal models. However, the utility of canine CMF models for evaluating MSC-based bone grafts rests on canine MSCs (cMSCs) responding in a similar manner to scaffold-based stimuli as human MSCs (hMSCs). Herein, cMSC and hMSC responses to polyethylene glycol (PEG)-based scaffolds were therefore compared in the presence or absence of osteoinductive polydimethylsiloxane (PDMS). Notably, the conjugation of PDMS to PEG-based constructs resulted in increases in both cMSC and hMSC osteopontin and calcium deposition. Based on these results, cMSCs were further used to assess the efficacy of tethered bone morphogenic protein 2 (BMP2) in enhancing PEG-PDMS scaffold osteoinductivity. Addition of low doses of tethered BMP2 (100 ng/mL) to PEG-PDMS systems increased cMSC expression of osterix and osteopontin compared to both PEG-PDMS and PEG-BMP2 controls. Furthermore, these increases were comparable to effects seen with up to 5-times higher BMP2 doses noted in literature. This article is protected by copyright. All rights reserved.