Bone formation ability of carbonate apatite-collagen scaffolds with different carbonate contents

Biological Properties and Medical Applications of Carbonate Apatite: A Systematic Review

Bone defects represent an everyday challenge for clinicians who work in the fields of orthopedic surgery, maxillofacial and oral surgery, otorhinolaryngology, and dental implantology. Various bone substitutes have been developed and utilized, according to the needs of bone reconstructive surgery. Carbonate apatite has gained popularity in recent years, due to its excellent tissue behavior and osteoconductive potential. This systematic review aims to evaluate the role of carbonate apatite in bone reconstructive surgery and tissue engineering, analyze its advantages and limitations, and suggest further directions for research and development. The Web of Science, PubMed, and Scopus electronic databases were searched for relevant review articles, published from January 2014 to 21 July 2023. The study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Eighteen studies were included in the present review. The biological properties and medical applications of carbonate apatite (CO3Ap) are discussed and evaluated. The majority of articles demonstrated that CO3Ap has excellent biocompatibility, resorbability, and osteoconductivity. Furthermore, it resembles bone tissue and causes minimal immunological reactions. Therefore, it may be successfully utilized in various medical applications, such as bone substitution, scaffolding, implant coating, drug delivery, and tissue engineering.

Synthetic mineral collagen composite bone graft with ribose cross linked collagen membrane for lateral ridge augmentation

A combination of calcium phosphate-based mineral with carbon apatite structure and type 1 collagen derived from bovine Achilles tendon has been introduced for augmentation of alveolar ridge and periodontal defects. Carbon apatite structure of mineral mimics natural bone in terms of resorption and remodeling, while collagen provides three-dimensional structure; both together aid in higher osteoconduction. The aim of present case report was to investigate if synthetic mineral collagen composite bone graft (CBG) with ribose cross-linked collagen membrane (RCLM) may be successfully used to obtain lateral augmentation of alveolar ridge that is planned for dental implant placement. Lateral augmentation of ridge was performed by elevating a full-thickness mucoperiosteal flap, followed by debridement and decortication of the defect area. CBG was soaked in saline and molded onto the defect area. RCLM was used to cover the graft site, followed by stabilization of membrane and the flap by suturing. Preoperative and postoperative ridge widths were measured using cone-beam computed tomography scans. The use of synthetic mineral collagen CBG with RCLM for lateral ridge augmentation may lead to increase in ridge width making it suitable for dental implant placement.

Biologically Inspired Collagen/Apatite Composite Biomaterials for Potential Use in Bone Tissue Regeneration-A Review

Type I collagen and nanocrystalline-substituted hydroxyapatite are the major components of a natural composite—bone tissue. Both of these materials also play a significant role in orthopedic surgery and implantology; however, their separate uses are limited; apatite is quite fragile, while collagen’s mechanical strength is very poor. Therefore, in biomaterial engineering, a combination of collagen and hydroxyapatite is used, which provides good mechanical properties with high biocompatibility and osteoinduction. In addition, the porous structure of the composites enables their use not only as bone defect fillers, but also as a drug release system providing controlled release of drugs directly to the bone. This feature makes biomimetic collagen–apatite composites a subject of research in many scientific centers. The review focuses on summarizing studies on biological activity, tested in vitro and in vivo.

Bone Regeneration in a Canine Model of Artificial Jaw Cleft Using Bone Marrow-Derived Mesenchymal Stem Cells and Carbonate Hydroxyapatite Carrier

OBJECTIVE

Cleft lip and palate (CLP) is a common anomaly of the orofacial region. Mesenchymal stem cell (MSC) transplantation has been a focus of regenerative medicine, and its application to the repair of bone defects in patients with CLP is highly anticipated. This study investigated the potential for using MSCs to regenerate bone in a jaw cleft as well as the survival of transplanted MSCs using a canine model of CLP.

DESIGN

Mesenchymal stem cells collected from the bone marrow of beagle dogs were transplanted along with carbonate hydroxyapatite into jaw clefts in beagle dogs. Mesenchymal stem cells labeled with fluorescent silica nanoparticles were also transplanted, and a histological analysis was performed 3 months later to evaluate MSC survival.

RESULTS

Carbonate hydroxyapatite regeneration into bone was enhanced by cotransplantation of MSCs. The survival rate of MSCs transplanted after 3 months was 5.7%.

CONCLUSIONS

Transplanted MSCs promote bone regeneration, although their survival rate is low.

The potential of carbonate apatite as an alternative bone substitute material

Bone reconstructive surgery has become a common procedure, and bone transplantation has become the second most frequently performed tissue transplantation procedure worldwide. Therefore, the need for bone substitute materials has increased. Artificial bone substitutes exhibit osteoconductive properties and feature several advantages, including abundant resources, low cost, and low donor site morbidity. Carbonate apatite (CO3Ap) is a calcium phosphate ceramic that can be used as a synthetic bone graft. The carbonate content of this ceramic is similar to that of bone apatite. In this review, we show that carbonate apatite can be degraded given its chemical reactivity in a weakly acidic environment and through osteoclast resorption. Moreover, it is osteoconductive and promotes bone tissue formation without fibrotic tissue formation. Additionally, microstructural analysis revealed that new bone tissue is formed within the bone graft itself.

Marine Waste Utilization as a Source of Functional and Health Compounds

Consumer demand for convenience has led to large quantities of seafood being value-added processed before marketing, resulting in large amounts of marine by-products being generated by processing industries. Several bioconversion processes have been proposed to transform some of these by-products. In addition to their relatively low value conventional use as animal feed and fertilizers, several investigations have been reported that have demonstrated the potential to add value to viscera, heads, skins, fins, trimmings, and crab and shrimp shells by extraction of lipids, bioactive peptides, enzymes, and other functional proteins and chitin that can be used in food and pharmaceutical applications. This chapter is focused on reviewing the opportunities for utilization of these marine by-products. The chapter discusses the various products and bioactive compounds that can be obtained from seafood waste and describes various methods that can be used to produce these products with the aim of highlighting opportunities to add value to these marine waste streams.

Comparative study on the resorbability and dissolution behavior of octacalcium phosphate, β-tricalcium phosphate, and hydroxyapatite under physiological conditions

The dissolution behaviors of octacalcium phosphate (OCP), β-tricalcium phosphate (β-TCP), and hydroxyapatite (HA) were compared by implanting the materials in rat subcutaneous pouches for 8 weeks using a filter chamber or immersing them in simulated body fluid (SBF) or Tris-HCl buffer for 2 weeks at pH 7.4 and 37(o)C. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and chemical analysis were conducted on these materials. Degree of supersaturation (DS) in the two solutions immersed with each calcium phosphate material was calculated from their chemical compositions. The results showed that OCP partially converted to apatitic crystals, while β-TCP and HA remained unchanged after the implantation. The DS of the SBF solution remained slightly supersaturated with respect to OCP and β-TCP, but slightly undersaturated in the Tris-HCl buffer. These findings suggest that previously reported OCP and β-TCP biodegradation could be induced through cell-mediated osteoclastic resorption rather than a simple dissolution process.

Biocalcite and Carbonic Acid Activators

Based on evolution of biomineralizing systems and energetic considerations, there is now compelling evidence that enzymes play a driving role in the formation of the inorganic skeletons from the simplest animals, the sponges, up to humans. Focusing on skeletons based on calcium minerals, the principle enzymes involved are the carbonic anhydrase (formation of the calcium carbonate-based skeletons of many invertebrates like the calcareous sponges, as well as deposition of the calcium carbonate bioseeds during human bone formation) and the alkaline phosphatase (providing the phosphate for bone calcium phosphate-hydroxyapatite formation). These two enzymes, both being involved in human bone formation, open novel not yet exploited targets for pharmacological intervention of human bone diseases like osteoporosis, using compounds that act as activators of these enzymes. This chapter focuses on carbonic anhydrases of biomedical interest and the search for potential activators of these enzymes, was well as the interplay between carbonic anhydrase-mediated calcium carbonate bioseed synthesis and metabolism of energy-rich inorganic polyphosphates. Beyond that, the combination of the two metabolic products, calcium carbonate and calcium-polyphosphate, if applied in an amorphous form, turned out to provide the basis for a new generation of scaffold materials for bone tissue engineering and repair that are, for the first time, morphogenetically active.

In vitro and in vivo evaluation of carbonate apatite-collagen scaffolds with some cytokines for bone tissue engineering

Background:

Collagen is regarded as one of the most useful biomaterials. We tried to combine collagen and carbonate apatite (CA) with some cytokines in order to enhance bone formation ability. In this study, we found that CA-collagen sponge (CA-CS) was a possible candidate of newly graft material for bone formation.

Materials and Methods:

CA-CS was fabricated by the following procedure. One wt% of pig hide collagen solution (Nippon Meat Packers. Inc., Tokyo, Japan) was neutralized with 0.1 N NaOH, and then mixed immediately 243 mg apatite powder with 0.06 M carbonate contents. After centrifugation at 1500 rpm for 10 min, excess water was removed, and the mixture was packed into Teflon molds (5.0 mm × 2.0 mm). Each 10 µg of basic fibroblast growth factor (bFGF) and recombinant human bone morphogenetic protein-2 (rh-BMP2) were involved in these sponges. Then these scaffolds frozen at −80°C for 2 h and dried in a freeze dry machine for 24 h. CA-CS without cytokines were also prepared as a control. Mouse osteoblast-like cell (MC3T3-E1) proliferations in these scaffolds were investigated by 3-day in vitro cell culture using MTT assay examination. Ten New Zealand rabbits (weight: 3–3.5 kg) were used in this in vivo study. After 3 weeks of placement, the scaffolds, rabbits were sacrificed, and bone formation in the sockets was evaluated histologically and histomorphometrically.

Results and Conclusion:

By histological observation and measurement of bone area ratio, CA-CS with cytokines showed higher bone formation ability (bFGF/CA-CS: 50.7 ± 7.3%, rh-BMP2/CA-CS: 54.2 ± 5.0%) than other groups. From the limited results of this study, it is suggested that CA collagen scaffolds with some cytokines may become an attractive scaffold for bone regeneration.

Isolation and Characterization of Nano-Hydroxyapatite from Salmon Fish Bone

Nano-Hydroxyapatite (nHA) was isolated from salmon bone by alkaline hydrolysis. The resulting nHA was characterized using several analytical tools, including thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), to determine the purity of the nHA sample. The removal of organic matter from the raw fish was confirmed by TGA. FT-IR confirmed the presence of a carbonated group and the similarities to synthetic Sigma HA. XRD revealed that the isolated nHA was amorphous. Microscopy demonstrated that the isolated nHA possessed a nanostructure with a size range of 6–37 nm. The obtained nHA interacted with mesenchymal stem cells (MSCs) and was non-toxic. Increased mineralization was observed for nHA treated MSCs compared to the control group. These results suggest that nHA derived from salmon is a promising biomaterial in the field of bone tissue engineering.

Biocalcite, a multifunctional inorganic polymer: Building block for calcareous sponge spicules and bioseed for the synthesis of calcium phosphate-based bone

Calcium carbonate is the material that builds up the spicules of the calcareous sponges. Recent results revealed that the calcium carbonate/biocalcite-based spicular skeleton of these animals is formed through an enzymatic mechanism, such as the skeleton of the siliceous sponges, evolutionarily the oldest animals that consist of biosilica. The enzyme that mediates the calcium carbonate deposition has been identified as a carbonic anhydrase (CA) and has been cloned from the calcareous sponge species Sycon raphanus. Calcium carbonate deposits are also found in vertebrate bones besides the main constituent, calcium phosphate/hydroxyapatite (HA). Evidence has been presented that during the initial phase of HA synthesis poorly crystalline carbonated apatite is deposited. Recent data summarized here indicate that during early bone formation calcium carbonate deposits enzymatically formed by CA, act as potential bioseeds for the precipitation of calcium phosphate mineral onto bone-forming osteoblasts. Two different calcium carbonate phases have been found during CA-driven enzymatic calcium carbonate deposition in in vitro assays: calcite crystals and round-shaped vaterite deposits. The CA provides a new target of potential anabolic agents for treatment of bone diseases; a first CA activator stimulating the CA-driven calcium carbonate deposition has been identified. In addition, the CA-driven calcium carbonate crystal formation can be frozen at the vaterite state in the presence of silintaphin-2, an aspartic acid/glutamic acid-rich sponge-specific protein. The discovery that calcium carbonate crystals act as bioseeds in human bone formation may allow the development of novel biomimetic scaffolds for bone tissue engineering. Na-alginate hydrogels, enriched with biosilica, have recently been demonstrated as a suitable matrix to embed bone forming cells for rapid prototyping bioprinting/3D cell printing applications.

New development of carbonate apatite-chitosan scaffold based on lyophilization technique for bone tissue engineering

Carbonate apatite-chitosan scaffolds (CA-ChSs) were fabricated using the lyophilization technique. It was found that ChSs prepared with 200 mg chitosan powder (ChSs200) had well-structured three-dimensional architecture with high porosity and good retentive form without brittleness. In addition, it was shown that the number of osteoblast-like cells MC3T3-E1 proliferated on desalinated ChSs200 was larger than that on the non-desalinated ChSs200. CA-ChSs were fabricated by adding 100 mg carbonate apatite (CA) to 200 mg chitosan gels followed by freeze-drying (CA100ChSs200). SEM observation revealed that CA100ChSs200 had favorable three- dimensional porous structures. The number of living cells increased more rapidly on CA100ChSs200 prepared with different amounts of CA than on ChSs. ALP activity significantly increased after day 14 and reached a plateau after day 21 in ChSs200 and CA100ChSs200. It was concluded that newly developed CA100ChSs200 may be a possible scaffold material for tissue engineering.

A novel glass ionomer cement containing MgCO(3 )apatite induced the increased proliferation and differentiation of human pulp cells in vitro

This study aimed to investigate the in vitro biological response of human dental pulp cells to glass ionomer cement (GIC, Fuji IX GP(®)) containing 2.5% magnesium carbonate apatite (MgCO(3)Ap). MgCO(3)Ap was synthesized by wet method and characterized using FT-IR, XPS, and SEM. Fuji IX GP(®) served as a control. Test and control cements were prepared by encapsulated mixing the powder with Fuji IX-liquid (P/L=3.6:1). Eluates from cements extracted by 1 mL culture medium were collected at day 1, 7 and 14, and used for WST-1 proliferation assay. For ALPase activity, cells were maintained with cements in transwells, harvested and enzyme activity was measured at day 1, 4, 7, 14, and 21. We found a higher cell proliferation and increased ALPase activity by pulp cells in the test group compared to the control. This suggests the potential of GIC containing this novel biological apatite as a restorative material for pulp-dentin regeneration.

Induction of carbonic anhydrase in SaOS-2 cells, exposed to bicarbonate and consequences for calcium phosphate crystal formation

Ca-phosphate/hydroxyapatite crystals constitute the mineralic matrix of vertebrate bones, while Ca-carbonate dominates the inorganic matrix of otoliths. In addition, Ca-carbonate has been identified in lower percentage in apatite crystals. By using the human osteogenic SaOS-2 cells it could be shown that after exposure of the cells to Ca-bicarbonate in vitro, at concentrations between 1 and 10 mm, a significant increase of Ca-deposit formation results. The crystallite nodules formed on the surfaces of SaOS-2 cells become denser and larger in the presence of bicarbonate if simultaneously added together with the mineralization activation cocktail (β-glycerophosphate/ascorbic acid/dexamethasone). In parallel, with the increase of Ca-deposit formation, the expression of the carbonic anhydrase-II (CA-II) gene becomes upregulated. This effect, measured on transcriptional level is also substantiated by immunohistological studies. The stimulatory effect of bicarbonate on Ca-deposit formation is prevented if the carbonic anhydrase inhibitor acetazolamide is added to the cultures. Mapping the surface of the Ca-deposit producing SaOS-2 cells by scanning electron microscopy coupled with energy-dispersive X-ray analysis revealed an accumulation of the signals for the element carbon and, as expected, also for phosphorus. Finally, it is shown that ortho-phosphate and hydrolysis products of polyphosphate inhibit CA-II activity, suggesting a feedback regulatory system between the CA-driven Ca-carbonate deposition and a subsequent inactivation of this process by ortho-phosphate. Based on the presented data we suggest that Ca-carbonate deposits act as bioseeds for a downstream Ca-phosphate deposition process. We propose that activators for CA, especially for CA-II, might be beneficial for the treatment of bone deficiency diseases.

Fabrication and characterization of biomimetic collagen-apatite scaffolds with tunable structures for bone tissue engineering

The objective of the current study is to prepare a biomimetic collagen-apatite scaffold for improved bone repair and regeneration. A novel bottom-up approach has been developed, which combines a biomimetic self-assembly method with a controllable freeze-casting technology. In this study, the mineralized collagen fibers were generated using a simple one-step co-precipitation method which involved collagen self-assembly and in situ apatite precipitation in a collagen-containing modified simulated body fluid (m-SBF). The precipitates were then subjected to controllable freeze casting, forming scaffolds with either an isotropic equiaxed structure or a unidirectional lamellar structure. These scaffolds were comprised of collagen fibers and poorly crystalline bone-like carbonated apatite nanoparticles. The mineral content in the scaffold could be tailored in the range 0-54wt.% by simply adjusting the collagen content in the m-SBF. Further, the mechanisms of the formation of both the equiaxed and the lamellar scaffolds were investigated, and freezing regimes for equiaxed and lamellar solidification were established. Finally, the bone-forming capability of such prepared scaffolds was evaluated in vivo in a mouse calvarial defect model. It was confirmed that the scaffolds well support new bone formation.

Maxillary sinus augmentation with adult mesenchymal stem cells: a review of the current literature

PURPOSE

Mesenchymal stem cells (MSCs) have been applied in maxillary sinus augmentation (MSA) with clinically successful results. The purpose of this article was to evaluate the systematically acquired evidence for the effectiveness of cell-based approaches in MSA with various scaffolds, and to narratively assess evidence from additional articles that report effectiveness of cell-based approaches in MSA.

MATERIALS AND METHODS

Electronic database searches were performed. Inclusion criteria were studies of cell-based approaches in MSA with various scaffolds, in humans, with at least 3 to 4 months of follow-up. Meta-analysis was performed for randomized controlled trials (RCTs) with histologic/histomorphometric evaluation.

RESULTS

Fifteen studies (4 RCTs) were considered to be eligible for inclusion in the review. The meta-analysis suggested a marginal, nonstatistically significant positive effect of MSCs on the bone regrowth.

CONCLUSIONS

A number of studies have demonstrated the potential for cell-based approaches in MSA; further RCTs that clearly demonstrate benefits of cell-based approach are needed.