Osseointegration of porous apatite-wollastonite and poly(lactic acid) composite structures created using 3D printing techniques.

A novel apatite-wollastonite/poly(lactic acid) (AW/PLA) composite structure, which matches cortical and cancellous bone properties has been produced and evaluated in vitro and in vivo. The composites structure has been produced using an innovative combination of 3D printed polymer and ceramic macrostructures, thermally bonded to create a hybrid composite structure. In vitro cell assays demonstrated that the AW structure alone, PLA structure alone, and AW/PLA composite were all biocompatible, with the AW structure supporting the proliferation and osteogenic differentiation of rat bone marrow stromal cells.

Preparation and characterisation of an innovative injectable calcium sulphate based bone cement for vertebroplasty application.

In this study, an innovative injectable and bioresorbable composite cement (Spine-Ghost) has been developed by combining a radiopaque glass-ceramic powder (SCNZgc) and spray-dried mesoporous bioactive particles (W-SC) into type III alpha calcium sulphate hemihydrate (α-CSH) (composition α-CSH/SCNZgc/W-SC, 70/20/10 wt%). The Spine-Ghost cement and pure α-CSH (as a reference) were characterised in terms of physical and mechanical properties and compared to a commercial reference (Cerament®- Bonesupport AB, Sweden). The Spine-Ghost cement had a setting time comparable with Cerament® showing a good injectability in the range of 8-20 minutes after the end of mixing.

Development of a methacrylate-terminated PLGA copolymer for potential use in craniomaxillofacial fracture plates.

We synthesised methacrylate-terminated PLGA (HT-PLGA, 85:15 LA:GA, 169kDa), for potential use as an adhesively attached craniomaxillofacial fracture fixation plate. The in vitro degradation of molecular weight, pH and flexural modulus were measured over 6weeks storage in PBS at 37°C, with commercially available high (225kDa, H-PLGA) and low (116kDa, L-PLGA) molecular weight 85:15 PLGAs used as comparators. Molecular weights of the materials reduced over 6weeks, HT-PLGA by 48%, H-PLGA by 23% and L-PLGA by 81%.

Transplanted Human Bone Marrow Mesenchymal Stem Cells Seeded onto Peptide Hydrogel Decrease Alveolar Bone Loss.

Alveolar bone loss can be caused by periodontitis or periodontal trauma. We have evaluated the effects of transplanted undifferentiated human mesenchymal stem cells (hMSCs) on alveolar bone reaction and periodontal ligament healing in an experimental periodontal wound model. The hMSCs seeded onto a self-assembling peptide hydrogel in combination with collagen sponge were implanted into the right mandible of 12 rats and followed for 1 (n=6) or 4 weeks (n=6) postoperatively.

Human fibroblast-derived extracellular matrix constructs for bone tissue engineering applications.

We exploited the biomimetic approach to generate constructs composed of synthetic biphasic calcium phosphate ceramic and extracellular matrix (SBC-ECM) derived from adult human dermal fibroblasts in complete xeno-free culture conditions. The construct morphology and composition were assessed by scanning electron microscopy, histology, immunohistochemistry, Western blot, glycosaminoglycan, and hydroxyproline assays. Residual DNA quantification, endotoxin testing, and local inflammatory response after implantation in a rat critical-sized calvarial defect were used to access the construct biocompatibility.

Bone marrow stromal cells enhance the osteogenic properties of hydroxyapatite scaffolds by modulating the foreign body reaction.

We aimed to investigate the osteogenic properties of bone marrow stromal cell (BMSC)-loaded biomimetic constructs composed of hydroxyapatite (HA), with or without in vitro cell-derived extracellular matrix (HA-ECM), and to assess the cellular components of the elicited foreign body reaction. HA-ECM constructs were produced by adult rat dermal fibroblasts cultured on top of synthetic HA microparticles. Rat calvarial critical-sized defects (8 mm) were created and treated with the generated HA-ECM constructs or HA microparticles, alone or combined with green fluorescent protein (GFP)-expressing BMSCs.

Cell-derived matrix enhances osteogenic properties of hydroxyapatite.

The study aimed to evaluate osteogenic properties of hydroxyapatite (HA) scaffold combined with extracellular matrix (ECM) derived in vitro from rat primary calvarial osteoblasts or dermal fibroblasts. The cellular viability, and the ECM deposited onto synthetic HA microparticles were assessed by MTT, Glycosaminoglycan, and Hydroxyproline assays as well as immunohistochemistry and scanning electron microscopy after 21 days of culture. The decellularized HA-ECM constructs were implanted in critical-sized calvarial defects of Sprague-Dawley rats, followed by bone repair and local inflammatory response assessments by histomorphometry and immunohistochemistry at 12 weeks postoperatively.

Early timing of low-dose dexamethasone decreases inflammation in a murine model of eosinophilic airway disease.

Conclusion: A very low dose of dexamethasone (DEX) was as equally as sufficient as a pharmacological dose to decrease eosinophil inflammation in airways and bone marrow. The timing of DEX treatment in relation to allergen challenge was strongly decisive for the outcome of the inflammatory response.

Objectives: We aimed to study compartmental allergic airway inflammatory responses to classic pharmacological and also extremely low physiological DEX dosage, given at different time points close to allergen challenge in a murine model.

Collagen-hydroxyapatite composite enhances regeneration of calvaria bone defects in young rats but postpones the regeneration of calvaria bone in aged rats.

The potential differences in bone repair of calvaria defects treated with a collagen sponge (HELISTAT) or a collagen-hydroxyapatite composite (HEALOS) in young and aged rats were evaluated at 8 weeks after surgery. A histomorphometric analysis of new bone formation and an evaluation of angiogenesis, mast cell, and eosinophil local infiltration were performed. Evaluation showed that HELISTAT induced a similar amount of new bone in both young and aged rats.

Local treatment of cricoid cartilage defects with rhBMP-2 induces growth plate-like morphology of chondrogenesis.

Objective: The ultrastructural characteristics of new bone and cartilage, induced at the site of cricoid cartilage defects treated with rhBMP-2 in rabbits, were investigated.

Study Design And Setting: A cricoid defect model was used. Fifteen rabbits were randomly and equally divided into 3 groups.

Cell origin in experimental repair of cricoid cartilage defects treated with recombinant human bone morphogenetic protein-2.

We determined the origin of new cartilage and new bone induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) at the site of cricoid cartilage defects in rabbits randomly divided into eight groups. The cricoid cartilage was split vertically along the anterior midline and a strip was excised from the anterior part of the cricoid cartilage in all rabbits. The perichondrium from the anterior part of the cricoid cartilage was trimmed off in four groups; two groups treated with rhBMP-2 and two control groups.

Effect of recombinant human BMP-2 on the repair of cricoid cartilage defects in young and adult rabbits: a comparative study.

Objective: The study evaluated the possible differences in the repair of cricoid cartilage defects treated with recombinant human BMP-2 in young and adult rabbits.

Methods: A cricoid defect rabbit model was used. Thirty rabbits were randomly divided into eight groups.

Recombinant human bone morphogenetic protein-2 enhances experimental laryngotracheal reconstruction in rabbits.

Objective: Bone morphogenetic protein-2 offers potential benefits for cartilage regeneration. We investigated the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) on the regeneration of laryngeal cartilage and respiratory epithelium in a rabbit model.

Material And Methods: We used a cricoid defect rabbit model.

Structural characteristics of repair tissue of cricoid cartilage defects treated with recombinant human bone morphogenetic protein-2.

We examined the structural characteristics of repair tissue induced by recombinant human bone morphogenetic protein-2 in a rabbit model of laryngotracheal reconstruction. Twenty-four New Zealand White rabbits were randomly divided into four groups of six rabbits. Two groups were treated with recombinant human bone morphogenetic protein-2 delivered on an absorbable collagen sponge, while two groups were used as controls.

Mifepristone (RU-486) impairs post-surgical wound healing of the larynx.

Background: The purpose of this study was to examine how RU486 (mifepristone), a glucocorticoid antagonist, affects the regeneration process in a rabbit laryngeal wound-healing model.

Material/methods: Eight rabbits underwent a cricoid-split operation with collagen sponge insertion. The animals were classified randomly into two groups (4 animals in each group): the RU486-treated group, with local administration of 3 mg RU486, and the control group, which was sham treated.