title: Tissue-engineered bone with 3-dimensionally printed β-tricalcium phosphate and polycaprolactone scaffolds and early implantation: an in vivo pilot study in a porcine mandible model.
abstract: OBJECTIVE
  Deep bone penetration into implanted scaffolds remains a challenge in tissue engineering. The purpose of this study was to evaluate bone penetration depth within 3-dimensionally (3D) printed β-tricalcium phosphate (β-TCP) and polycaprolactone (PCL) scaffolds, seeded with porcine bone marrow progenitor cells (pBMPCs), and implanted early in vivo.
  
  
  METHODS
  Scaffolds were 3D printed with 50% β-TCP and 50% PCL. The pBMPCs were harvested, isolated, expanded, and differentiated into osteoblasts. Cells were seeded into the scaffolds and constructs were incubated in a rotational oxygen-permeable bioreactor system for 14 days. Six 2- × 2-cm defects were created in each mandible (N = 2 minipigs). In total, 6 constructs were placed within defects and 6 defects were used as controls (unseeded scaffolds, n = 3; empty defects, n = 3). Eight weeks after surgery, specimens were harvested and analyzed by hematoxylin and eosin (H&E), 4',6-diamidino-2-phenylindole (DAPI), and CD31 staining. Analysis included cell counts, bone penetration, and angiogenesis at the center of the specimens.
  
  
  RESULTS
  All specimens (N = 12) showed bone formation similar to native bone at the periphery. Of 6 constructs, 4 exhibited bone formation in the center. Histomorphometric analysis of the H&E-stained sections showed an average of 22.1% of bone in the center of the constructs group compared with 1.87% in the unseeded scaffolds (P < .05). The 2 remaining constructs, which did not display areas of mature bone in the center, showed massive cell penetration depth by DAPI staining, with an average of 2,109 cells/0.57 mm(2) in the center compared with 1,114 cells/0.57 mm(2) in the controls (P < .05). CD31 expression was greater in the center of the constructs compared with the unseeded scaffolds (P < .05).
  
  
  CONCLUSIONS
  3D printed β-TCP and PCL scaffolds seeded with pBMPCs and implanted early into porcine mandibular defects display good bone penetration depth. Further study with a larger sample and larger bone defects should be performed before human applications.
authors.affiliation: Research Fellow, Skeletal Biology Research Center, Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Boston, MA; Resident, Department of Oral and Maxillofacial Surgery, Lille University Hospital, Lille, France. Electronic address: sandra.konopnicki@gmail.com.
authors.forename: Sandra
authors.initials: S
authors.lastname: Konopnicki
authors.affiliation: Plastic and Facial Surgeon, Division of Plastic Surgery, Department of Surgery, Mayo Clinic, Rochester, MN.
authors.forename: Basel
authors.initials: B
authors.lastname: Sharaf
authors.affiliation: Attending Surgeon, Department of Plastic and Oral Surgery, Boston Children's Hospital, Boston, MA; Instructor, Department of Oral and Maxillofacial Surgery, Harvard School of Dental Medicine and Harvard Medical School, Boston, MA.
authors.forename: Cory
authors.initials: C
authors.lastname: Resnick
authors.affiliation: Student, Harvard School of Dental Medicine, Boston, MA.
authors.forename: Adam
authors.initials: A
authors.lastname: Patenaude
authors.affiliation: Former Student, Harvard School of Dental Medicine, Boston, MA. Currently, Orthodontist, Lindner Dental Associates, P.C, Bedford, NH.
authors.forename: Tracy
authors.initials: T
authors.lastname: Pogal-Sussman
authors.affiliation: Professor, Department of Dentistry/Oral and Maxillofacial Surgery, College of Medicine, Hanyang University, Seoul, Korea.
authors.forename: Kyung-Gyun
authors.initials: KG
authors.lastname: Hwang
authors.affiliation: Instructor, Department of Oral and Maxillofacial Surgery, Tokyo Medical University Hospital, Tokyo, Japan.
authors.forename: Harutsugi
authors.initials: H
authors.lastname: Abukawa
authors.affiliation: Associate Professor and Director of Minimally Invasive Oral and Maxillofacial Surgery and Residency Program, Skeletal Biology Research Center, Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Boston, MA; Harvard School of Dental Medicine and Harvard Medical School, Boston, MA.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Troulis
mesh_terms: D000818:Animals; D002130:Calcium Phosphates; D008334:Mandible; D023421:Models, Animal; D010865:Pilot Projects; D011091:Polyesters; D066330:Printing, Three-Dimensional; D013552:Swine; D013556:Swine, Miniature; D023822:Tissue Engineering; D054457:Tissue Scaffolds
chemical_list: D002130:Calcium Phosphates; D011091:Polyesters; C485817:beta-tricalcium phosphate; C016240:polycaprolactone