Copyright © 2019 American Society of Plastic Surgeons. Unauthorized reproduction of this article is prohibited. www.PRSJournal.com 1385 C left lip and palate are the most commonly encountered congenital craniofacial anom- alies, affecting up to one in 500 births. 1,2 These defects adversely affect feeding, hearing, and speaking, and have significant negative psy- chological impacts on the affected infants and their families. Clefts of the anterior palate are frequently repaired by using autologous bone grafts harvested from the iliac crest. 3 Recently, minimally invasive harvest techniques from iliac crest 4 have been performed, leading to fewer complications, less pain, and shorter hospital stays. 3 However, autologous bone graft sometimes results in insufficient outcome. Some degree of bone resorption occurs, with reports indicating approximately 40 percent bone resorption rate 1 year after the graft using iliac crest bone. 5,6 This may increase the need for secondary procedures. In addition, in some cases, adequate augmenta- tion of the bone defect is made difficult by the width of the gap between the maxillary segments. Disclosure: The authors have no commercial asso- ciations or financial disclosures that might pose a conflict of interest with any information presented in this article. Copyright © 2019 by the American Society of Plastic Surgeons DOI: 10.1097/PRS.0000000000005528 Reena Bakshi, M.D. Akishige Hokugo, D.D.S., Ph.D. Situo Zhou, M.D. Zheyu Zhang, B.S. Lixin Wang, D.M.D. Kameron Rezzadeh, M.D. Luis Andres Segovia, M.D. Reza Jarrahy, M.D. Los Angeles, Calif. Background: Bone morphogenetic proteins (BMPs) have played a central role in the regenerative therapies for bone reconstruction, including alveolar cleft and craniofacial surgery. However, the high cost and significant adverse effect of BMPs limit their broad application. Hydroxycholesterols, naturally occur- ring products of cholesterol oxidation, are a promising alternative to BMPs. The authors studied the osteogenic capability of hydroxycholesterols on hu- man mesenchymal stem cells and the impact of hydroxycholesterols on a ro- dent alveolar cleft model. Methods: Human mesenchymal stem cells were treated with control medium or osteogenic medium with or without hydroxycholesterols. Evaluation of cel- lular osteogenic activity was performed. A critical-size alveolar cleft was cre- ated and one of the following treatment options was assigned randomly to each defect: collagen sponge incorporated with hydroxycholesterols, BMP-2, or no treatment. Bone regeneration was assessed by means of radiologic and histologic analyses and local inflammation in the cleft evaluated. Moreover, the role of the hedgehog signaling pathway in hydroxycholesterol-mediated osteogenesis was examined. Results: All cellular osteogenic activities were significantly increased on hu- man mesenchymal stem cells treated with hydroxycholesterols relative to oth- ers. The alveolar cleft treated with collagen sponge with hydroxycholesterols and BMP-2 demonstrated robust bone regeneration. The hydroxycholesterol group revealed histologically complete bridging of the alveolar defect with architecturally mature new bone. The inflammatory responses were less in the hydroxycholesterol group compared with the BMP-2 group. Induction of hydroxycholesterol-mediated in vitro osteogenesis and in vivo bone regenera- tion were attenuated by hedgehog signaling inhibitor, implicating involvement of the hedgehog signaling pathway. Conclusion: Hydroxycholesterols may represent a viable alternative to BMP-2 in bone tissue engineering for alveolar cleft. (Plast. Reconstr. Surg. 143: 1385, 2019.) From the Regenerative Bioengineering and Repair Labora- tory, Division of Plastic and Reconstructive Surgery, Depart- ment of Surgery, David Geffen School of Medicine, Univer- sity of California, Los Angeles. Received for publication February 6, 2018; accepted Septem- ber 14, 2018. The first two authors contributed equally to this study. Application of Hydroxycholesterols for Alveolar Cleft Osteoplasty in a Rodent Model EXPERIMENTAL