The Adjunctive Use of MSC Secretome for Guided Bone Regeneration: An Experimental In Vivo Investigation.

OBJECTIVE

To evaluate the efficacy of mesenchymal stromal cells' (MSC) secretome delivered as conditioned media (CM) as an adjunct to a xenograft (XG) and collagen membrane (MEM) for guided bone regeneration (GBR) in chronic non-contained mandibular defects in minipigs.

METHODS

Chronic bilateral mandibular defects were surgically created in seven minipigs. In a split-mouth design, defects were treated with either CM-functionalized (test) or native XG + MEM (control) and evaluated after 4 and 12 weeks. New bone formation was assessed using in vivo computed tomography (CT) and ex vivo micro-CT, histology and immunohistochemistry (IHC). Quantitative CT, micro-CT and histomorphometric data were statistically analysed.

RESULTS

No significant differences in new bone formation were observed between the test and control group at either timepoint. These findings could be partly explained by a high intrinsic healing capacity and continual growth of the animals. Minimal residual XG material was detected in both groups at 4 and 12 weeks. When present, these remnants were associated with multinucleated Cathepsin K-positive cells (IHC) with no observable differences between the groups.

CONCLUSION

The adjunctive use of MSC secretome in combination with XG and MEM did not improve GBR outcomes in chronic non-contained mandibular defects in the present minipig model. The suitability of this animal model for experimental GBR may be questionable.