Appropriate pore size for bone formation potential of porous collagen type I-based recombinant peptide

Shoji Yamahara; Jorge Luis Montenegro Raudales; Yasunori Akiyama; Masaaki Ito; Ichinnorov Chimedtseren; Yoshinori Arai; Taku Wakita; Takahiro Hiratsuka; Ken Miyazawa; Shigemi Goto; Masaki Honda

doi:10.1016/j.reth.2022.08.001

Appropriate pore size for bone formation potential of porous collagen type I-based recombinant peptide

Regen Ther. 2022 Aug 29:21:294-306. doi: 10.1016/j.reth.2022.08.001. eCollection 2022 Dec.

Authors

Shoji Yamahara^{1

2}, Jorge Luis Montenegro Raudales², Yasunori Akiyama^{3

2}, Masaaki Ito^{3

2}, Ichinnorov Chimedtseren^{3

2}, Yoshinori Arai⁴, Taku Wakita⁵, Takahiro Hiratsuka⁵, Ken Miyazawa¹, Shigemi Goto¹, Masaki Honda²

Affiliations

¹ Department of Orthodontics, School of Dentistry, Aichi Gakuin University, 2-11 Suemori-dori, Chikusa-ku, Nagoya, Aichi, 464-8651, Japan.
² Department of Oral Anatomy, School of Dentistry, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi 464-8650, Japan.
³ Division of Research and Treatment for Oral and Maxillofacial Congenital Anomalies, School of Dentistry, Aichi Gakuin University, 2-11 Suemori-dori, Chikusa-ku, Nagoya, Aichi, 464-8651, Japan.
⁴ Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
⁵ Bio Science & Engineering Laboratory, FUJIFILM Corporation, 577 Ushijima, Kaisei-machi, Ashigarakami-gun, Kanagawa 258-8577, Japan.

Abstract

Introduction: In this study, we developed porous medium cross-linked recombinant collagen peptide (mRCP) with two different ranges of interconnected pore sizes, Small-mRCP (S-mRCP) with a range of 100-300 μm and Large-mRCP (L-mRCP) with a range of 200-500 μm, to compare the effect of pore size on bone regeneration in a calvarial bone defect.

Methods: Calvarial bone defects were created in Sprague-Dawley rats through a surgical procedure. The rats were divided into 2 groups: S-mRCP implanted group and L-mRCP implanted group. The newly formed bone volume and bone mineral density (BMD) was evaluated by micro-computed tomography (micro-CT) immediately after implantation and at 1, 2, 3, and 4 weeks after implantation. In addition, histological analyses were carried out with hematoxylin and eosin (H&E) staining at 4 weeks after implantation to measure the newly formed bone area between each group in the entire defect, as well as the central side, the two peripheral sides (right and left), the periosteal (top) side and the dura matter (bottom) side of the defect.

Results: Micro-CT analysis showed no significant differences in the amount of bone volume between the S-mRCP and L-mRCP implanted groups at 1, 2, 3 and 4 weeks after implantation. BMD was equivalent to that of the adjacent native calvaria bone at 4 weeks after implantation. H&E images showed that the newly formed bone area in the entire defect was significantly larger in the S-mRCP implanted group than in the L-mRCP implanted group. Furthermore, the amount of newly formed bone area in all sides of the defect was significantly more in the S-mRCP implanted group than in the L-mRCP implanted group.

Conclusion: These results indicate that the smaller pore size range of 100-300 μm is appropriate for mRCP in bone regeneration.

Keywords: ALP, alkaline phosphatase; BMD, bone mineral density; Bone reconstruction; Bone substitute; CSD, critical-size defect; Calvaria; DHT, dehydothermal treatment; H&E, hematoxylin and eosin; Interconnected pore; Pore size; RCP, recombinant collagen peptide; RGD, arginyl- glycyl- aspartic acid; ROIs, regions of interest; Recombinant human collagen peptide; SD, standard deviation; TRAP, tartrate-resistant acid phosphatase; mRCP, medium-cross-linked RCP; micro-CT, micro-computed tomography.