NELL-1 is a secreted, osteogenic protein first discovered to control ossification of the cranial skeleton. Recently, NELL-1 has been implicated in bone maintenance. However, the cellular determinants of NELL-1’s bone-forming effects are still unknown. Here, recombinant human NELL-1 (rhNELL-1) implantation was examined in a clinically relevant nonhuman primate lumbar spinal fusion model. Prolonged rhNELL-1 protein release was achieved using an apatite-coated β-tricalcium phosphate carrier, resulting in a local influx of stem cell antigen-1–positive (Sca-1+) mesenchymal progenitor cells (MPCs), and complete osseous fusion across all samples (100% spinal fusion rate). Murine studies revealed that
Aaron W. James, Jia Shen, Rebecca Tsuei, Alan Nguyen, Kevork Khadarian, Carolyn A. Meyers, Hsin Chuan Pan, Weiming Li, Jin H. Kwak, Greg Asatrian, Cymbeline T. Culiat, Min Lee, Kang Ting, Xinli Zhang, Chia Soo
RhNELL-1 systemic injection in mouse: radiographic analysis.