Mastoid obliteration using a hyaluronic acid gel to deliver a mesenchymal stem cells-loaded demineralized bone matrix: An experimental study

SummaryBackground and objectiveThe aim of this study was to evaluate whether a combination of expanded human mesenchymal stem cells (hMSCs) with hyaluronic acid gel in human demineralized bone matrix (hDBM) can promote osteogenesis in a mastoid obliteration procedure, with using the guinea pig as an animal model.Materials and methodsFourteen male guinea pigs were used for the experiment. Bulla obliteration using 6-diamidino-2-phenylindole (DAPI)-labeled hMSCs (2 × 106) loaded into hDBM with hyaluronic acid hydrogel was performed in the experimental group (n = 7). The control group was obliterated using hDBM only (n = 7). The histologic findings and microCT images were obtained from each bulla at 3 and 7 weeks postsurgery.ResultsThe increased soft tissue intensity caused by chondrogenic differentiation around the implanted hMSCs-loaded hDBM was identified, as compared to the hMSCs-free hDBM group. All the hMSCs-loaded hDBM at 7 weeks post-implantation displayed greater amounts of bone filling the bulla space, as compared to the hMSCs-free hDBM implanted group. In the hMSCs-free hDBM group, microCT shows incomplete new bone formation, as compared to the hyaluronic acid gel-hMSCs treated group.ConclusionThe successful formation of bone using allogeneic hMSCs loaded onto hDBM and hyaluronic acid hydrogel to repair critically sized bulla defects in the guinea pig model was accompanied with the absence of any local response to the foreign cells. The use of hMSCs-loaded hDBM and hyaluronic acid hydrogel is appropriate for performing clinical mastoid obliteration.