Citric Acid-based Hydroxyapatite Composite Scaffolds Enhance Calvarial Regeneration

Abstract

Citric acid-based polymer/hydroxyapatite composites (CABP-HAs) are a novel class of biomimetic composites that have recently attracted significant attention in tissue engineering. The objective of this study was to compare the efficacy of using two different CABP-HAs, poly (1,8-octanediol citrate)-click-HA (POC-Click-HA) and crosslinked urethane-doped polyester-HA (CUPE-HA) as an alternative to autologous tissue grafts in the repair of skeletal defects. CABP-HA disc-shaped scaffolds (65 wt.-% HA with 70% porosity) were used as bare implants without the addition of growth factors or cells to renovate 4 mm diameter rat calvarial defects (n = 72, n = 18 per group). Defects were either left empty (negative control group), or treated with CUPE-HA scaffolds, POC-Click-HA scaffolds, or autologous bone grafts (AB group). Radiological and histological data showed a significant enhancement of osteogenesis in defects treated with CUPE-HA scaffolds when compared to POC-Click-HA scaffolds. Both, POC-Click-HA and CUPE-HA scaffolds, resulted in enhanced bone mineral density, trabecular thickness, and angiogenesis when compared to the control groups at 1, 3, and 6 months post-trauma. These results show the potential of CABP-HA bare implants as biocompatible, osteogenic, and off-shelf-available options in the repair of orthopedic defects.

The Effects of Regenerative Materials on Biomarkers, Clinical and Radiological Features of Healing Defects Treated by Guided Bone Regeneration

“…Radiological evaluation has been used by several researchers to examine the progress of bone healing in clinical and animal experiments [40,41]. The current study findings support the previous reports suggesting that the use of BRMs promotes bone defect healing.…”

“…On the other hand, the Control group had significantly lower bone density than Bio Oss and β-TCP only at one-month post GBR, while the bone density difference across the groups at two-month post GBR was not statistically significant. Sun et al [40] however, reported an enhanced bone mineral density, trabecular thickness, and angiogenesis when comparing regenerative defects to the control groups at 1 st , 3…”

Nano-hydroxyapatite modulates osteoblast lineage commitment by stimulation of DNA methylation and regulation of gene expression

“…Recently, HA is being investigated for use in various nanomaterials for its potential biocompatibility as well as osteoinductive properties [31–33]. Synthetic hydroxyapatite (HAp) is essentially identical to naturally occurring HA and has therefore become a commonly investigated biomaterial for use in skeletal, orthopedic, and dental repair, in part, by enhancing cell attachment, proliferation, and mineral formation [34–37]. Nano-HAp is now being investigated as a biomaterial to be used; directly as a therapeutic, a major component of bone graft substitutes, and an implant coating to improve biocompatibility and skeletal repair (reviewed in [36, 38–40]).…”

Accelerated Self-Hardening Tetracalcium Phosphate Based Bone Cement with Enhanced Strength and Biological Behaviour

“…CA has been shown to exhibit osteoinductivity by enhancing alkaline phosphatase (ALP) and osterix (OSX) gene expression from in vitro studies [22]. Another study on effect of citric acid-based hydroxyapatite composite on stem cells reported that citrate may have considerable effect on bone development for orthopedic biomaterials [23]. Hence, it can be concluded that CA present in CPC may enhance the bone formation.…”