A GelMA/polydopamine hydrogel with PTH and osteogenically stimulated alveolar mucosa-derived stem cells promotes bone regeneration in MRONJ-affected wounds.

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is a serious complication in patients taking bisphosphonates. This study aimed at developing a mesenchymal stem cell-based strategy to reduce the incidence of MRONJ and recover regeneration capability of MRONJ-affected wounds by using a gelatin methacryloyl/polydopamine hydrogel (GelMA/PD) to adhere alveolar mucosa-derived stem cells (AMCs) on the bone surface, with the osteogenically stimulated AMCs modulated by microRNA (miR) transfection, and the osteoanabolic environment activated by parathyroid hormone (PTH).

METHODS

GelMA/PD was synthesized by photo-crosslinking, and the incorporation of PD onto GelMA as well as mechanical properties were assessed. Rat AMCs were isolated, and the stemness was characterized. AMCs were osteogenically stimulated by miR transfection. Maxillary osteotomy was created in rats administrated with zoledronic acid and dexamethasone to simulate MRONJ-affected wounds, and osteotomy in rats without ZA served as healthy controls. Wounds were unfilled or filled with GelMA/PD alone, GelMA/PD with AMCs (GA), GelMA/PD with OAMCs (GO), or GelMA/PD with OAMCs and PTH (PO), and were assessed by gross observation, micro-CT imaging, histology, and immunohistochemistry for osteoblast-osteoclast coupling.

RESULTS

GelMA/PD exhibited modestly decreased compressive strength and superior adhesion strength compared with GelMA. AMCs were double positive for CD73 and CD90, showed trilineage differentiation capability, and were osteogenically stimulated by miR-218 transfection. Among MRONJ-affected wounds, soft tissue coverage was accelerated, with reduced sequestra and significantly greater bone volume in PO group (38.46 ± 10.02%) relative to unfilled group (21.81 ± 6.18%), and osteoblast-osteoclast coupling was evident in GO and PO groups. Soft tissue recovery, inflammation reduction, and matrix deposition on defect surfaces were more prominent in PO group.

CONCLUSION

GelMA/PD loaded with PTH and microRNA-218-transfected AMCs could facilitate mucosal healing, recover the osteoblast-osteoclast coupling, and repair MRONJ-affected wounds, and might be a feasible strategy for managing MRONJ.