Pyk2 deficiency enhances bone mass during midpalatal suture expansion

Jun Sun, Pierre P. Eleniste, Achint Utreja, Hakan Turkkahraman, Sean Shih Yao Liu, Angela Bruzzaniti

Research output: Contribution to journalArticlepeer-review


Objective: To determine if Pyk2 deficiency increases midpalatal suture bone mass and preserves sutural integrity after maxillary expansion. Setting and Sample: Thirty-six male Pyk2 knockout (KO) and control (WT) mice at 6 weeks of age. Materials and Methods: Mice received nickel-titanium spring expanders delivering 0 g (no intervention control), 10 or 20 g force for 14 days. High-resolution micro-CT was used to determine bone volume/tissue volume (BV/TV), sutural width and intermolar width. Effects on osteoclasts, chondrocytes and suture morphology were determined by histomorphometry. Results: Pyk2-KO controls (0 g) had 7% higher BV/TV compared with WT controls. Expanded Pyk2-KO maxillae also exhibited 12% (10 g) and 18% (20 g) higher BV/TV than WT mice. Although bone loss following expansion occurred in both genotypes, BV/TV was decreased to a greater extent in WT maxillae (−10% at 10g; −22% at 20 g) compared with Pyk2-KO maxillae (−11% only at 20 g). Expanded WT maxillae also showed a greater increase in sutural width, intermolar width and fibrous connective tissue width compared with expanded Pyk2-KO maxillae. Moreover, osteoclast number was increased 77% (10 g) and 132% (20 g) in expanded WT maxillae, but remained unchanged in expanded Pyk2-KO, compared to their respective controls. Cartilage area and chondrocyte number were increased to the same extent in expanded WT and Pyk2-KO sutures. Conclusions: These findings suggest that midpalatal suture expansion increases osteoclast formation in WT but not Pyk2-KO mice, leading to higher BV/TV in expanded Pyk2-KO maxillae. These studies suggest Pyk2-targeted strategies may be beneficial to increase bone density and preserve sutural integrity during maxillary expansion.

Original languageEnglish (US)
Pages (from-to)501-508
Number of pages8
JournalOrthodontics and Craniofacial Research
Issue number4
StatePublished - Nov 1 2020


  • bone remodelling
  • mechanical force
  • orthodontic
  • osteoblast
  • osteoclast
  • rapid maxilla expansion

ASJC Scopus subject areas

  • Orthodontics
  • Surgery
  • Oral Surgery
  • Otorhinolaryngology

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