Schneiderian membrane-derived cells have inferior bone-forming capacities compared to other human periosteal-derived cells.

Skeletal stem and progenitor cells (SSPCs) are a key component of bone tissue engineering strategies for treating large bone defects. The Schneiderian membrane, a bone-lining membrane of the maxillary sinus, has been proposed as a source of cells with bone-forming capacity. Cells were isolated from human Schneiderian membrane (hSMs) samples obtained during Le Fort I orthognathic surgery and compared with previously characterised human periosteal-derived cells (hPDCs) from tibial and mandibular origins. Proliferation, metabolic activity, cellular senescence, surface marker expression, and trilineage differentiation were assessed in vitro. Bone-forming capacity was evaluated by ectopic subcutaneous implantation of cell-seeded NuOss scaffolds in nude mice for 8 weeks, followed by Nano-CT quantification and histological analysis. hSMs exhibited proliferation, metabolic activity and senescence levels comparable to hPDCs. Flow cytometry confirmed positivity for CD73, CD90, CD105 and CD164, and negativity for CD146, CD31, CD45 and CD235ab. Unlike hPDCs, hSMs lacked CD200 expression. Chondrogenic differentiation was confirmed by Alcian Blue staining and upregulation of COL2A1, COL10A1 and RUNX2. Bone formation was detected in 4 of 12 implanted constructs, with a mean mineralised tissue volume of 0.49%, which was lower than that reported for mandibular and tibial hPDCs under identical conditions. hSMs can be isolated, expanded and differentiated, and retain limited bone-forming capacity in vivo. However, their osteogenic performance is inferior to that of mandibular and tibial hPDCs. Given the more invasive harvest procedure, hSMs should be considered as a cell source only when the maxillary sinus is already surgically accessible.