<i>In vivo</i>imaging techniques for bone tissue engineering

Fragogeorgi, Eirini; Rouchota, Maritina; Γεωργίου, Μαρία; Vélez, Marisela; Bouziotis, Penelope; Loudos, George

doi:10.1177/2041731419854586

Cited by 33 publications

(29 citation statements)

References 61 publications

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“…In addition to ex vivo microCT evaluation, our group performed an in vivo assessment using microPET scans to identify active bone remodeling ongoing at the defect site. Several authors have demonstrated that this is a sensitive and valuable modality for evaluating bone regeneration following implantation of biomaterials 30,41,42 . Our results demonstrated a trend toward increased metabolic activity within the XG groups when compared to DBM.…”

Section: Discussionsupporting

confidence: 58%

Improved osseointegration using porcine xenograft compared to demineralized bone matrix for the treatment of critical defects in a small animal model

Jinnah

Whitlock

Willey

et al. 2020

Xenotransplantation

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Background Autograft (AG) is the gold standard bone graft due to biocompatibility, osteoconductivity, osteogenicity, and osteoinductivity. Alternatives include allografts and xenografts (XG). Methods We investigated the osseointegration and biocompatibility of a decellularized porcine XG within a critical defect animal model. We hypothesized that the XG will result in superior osseointegration compared to demineralized bone matrix (DBM) and equivalent immune response to AG. Critical defects were created in rat femurs and treated with XG, XG plus bone morphogenetic protein (BMP)‐2, DBM, or AG. Interleukin (IL)‐2 and IFN‐gamma levels (inflammatory markers) were measured from animal blood draws at 1 week and 1 month post‐operatively. At 1 month, samples underwent micro‐positron‐emission tomography (microPET) scans following 18‐NaF injection. At 16 weeks, femurs were retrieved and sent for micro‐computerized tomography (microCT) scans for blinded grading of osseointegration or were processed for histologic analysis with tartrate resistant acid phosphatase (TRAP) and pentachrome. Results Enzyme linked immunosorbent assay testing demonstrated greater IL‐2 levels in the XG vs. AG 1 week post‐op; which normalized by 28 days post‐op. MicroPET scans showed increased uptake within the AG compared to all groups. XG and XG + BMP‐2 showed a trend toward increased uptake compared with DBM. MicroCT scans demonstrated increased osseointegration in XG and XG + BMP groups compared to DBM. Pentachrome staining demonstrated angiogenesis and endochondral bone formation. Furthermore, positive TRAP staining in samples from all groups indicated bone remodeling. Conclusions These data suggest that decellularized and oxidized porcine XG is biocompatible and at least equivalent to DBM in the treatment of a critical defect in a rat femur model.

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Section: Discussionsupporting

confidence: 58%

Improved osseointegration using porcine xenograft compared to demineralized bone matrix for the treatment of critical defects in a small animal model

Jinnah

Whitlock

Willey

et al. 2020

Xenotransplantation

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“…defects smaller than this size can regenerate spontaneously, previous studies by our group have shown 5 mm to be critical [30]. Moreover a number of studies have chosen a 5 mm defect as a standard bilateral skull defect in the rat to minimize the animal numbers used and meet the 3R criteria (Reduction, Replacement, Refinement) [31,32]. Also, a defect of the cranium is a commonly used model to evaluate bone reconstruction due to the absent blood supply, lack of muscle tissue and poor bone repair [31].…”

Section: Discussionmentioning

confidence: 99%

In vivo bone regeneration assessment of offset and gradient melt electrowritten (MEW) PCL scaffolds

et al. 2020

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Background Biomaterial-based bone tissue engineering represents a promising solution to overcome reduced residual bone volume. It has been previously demonstrated that gradient and offset architectures of three-dimensional melt electrowritten poly-caprolactone (PCL) scaffolds could successfully direct osteoblast cells differentiation toward an osteogenic lineage, resulting in mineralization. The aim of this study was therefore to evaluate the in vivo osteoconductive capacity of PCL scaffolds with these different architectures. Methods Five different calcium phosphate (CaP) coated melt electrowritten PCL pore sized scaffolds: 250 μm and 500 μm, 500 μm with 50% fibre offset (offset.50.50), tri layer gradient 250–500-750 μm (grad.250top) and 750–500-250 μm (grad.750top) were implanted into rodent critical-sized calvarial defects. Empty defects were used as a control. After 4 and 8 weeks of healing, the new bone was assessed by micro-computed tomography and immunohistochemistry. Results Significantly more newly formed bone was shown in the grad.250top scaffold 8 weeks post-implantation. Histological investigation also showed that soft tissue was replaced with newly formed bone and fully covered the grad.250top scaffold. While, the bone healing did not happen completely in the 250 μm, offset.50.50 scaffolds and blank calvaria defects following 8 weeks of implantation. Immunohistochemical analysis showed the expression of osteogenic markers was present in all scaffold groups at both time points. The mineralization marker Osteocalcin was detected with the highest intensity in the grad.250top and 500 μm scaffolds. Moreover, the expression of the endothelial markers showed that robust angiogenesis was involved in the repair process. Conclusions These results suggest that the gradient pore size structure provides superior conditions for bone regeneration.

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“…As ions released from these glasses already exist in the body, problems related to toxicity and inflammatory reactions are avoided (Foroutan et al, 2015). However, silicate-based glasses have a poor solubility and typically they take several years to dissolve in a physiological environment (Fragogeorgi et al, 2019). Therefore, they cannot be used as temporary implants and their long-term effects in the body are still unknown.…”

Section: Introductionmentioning

confidence: 99%

Mesoporous Strontium-Doped Phosphate-Based Sol-Gel Glasses for Biomedical Applications

et al. 2020

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Mesoporous phosphate-based glasses have great potential as biomedical materials being able to simultaneously induce tissue regeneration and controlled release of therapeutic molecules. In the present study, a series of mesoporous phosphate-based glasses in the P 2 O 5-CaO-Na 2 O system, doped with 1, 3, and 5 mol% of Sr 2+ , were prepared using the sol-gel method combined with supramolecular templating. A sample without strontium addition was prepared for comparison. The non-ionic triblock copolymer EO 20 PO 70 EO 20 (P123) was used as a templating agent. Scanning electron microscopy (SEM) images revealed that all synthesized glasses have an extended porous structure. This was confirmed by N 2 adsorption-desorption analysis at 77 K that shows a porosity typical of mesoporous materials. 31 P magic angle spinning nuclear magnetic resonance (31 P MAS-NMR) and Fourier transform infrared (FTIR) spectroscopies have shown that the glasses are mainly formed by Q 1 and Q 2 phosphate groups. Degradation of the glasses in deionized water assessed over a 7-day period shows that phosphate, Ca 2+ , Na + , and Sr 2+ ions can be released in a controlled manner over time. In particular, a direct correlation between strontium content and degradation rate was observed. This study shows that Sr-doped mesoporous phosphate-based glasses have great potential in bone tissue regeneration as materials for controlled delivery of therapeutic ions.

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In vivoimaging techniques for bone tissue engineering

Cited by 33 publications

References 61 publications

Improved osseointegration using porcine xenograft compared to demineralized bone matrix for the treatment of critical defects in a small animal model

Improved osseointegration using porcine xenograft compared to demineralized bone matrix for the treatment of critical defects in a small animal model

In vivo bone regeneration assessment of offset and gradient melt electrowritten (MEW) PCL scaffolds

Mesoporous Strontium-Doped Phosphate-Based Sol-Gel Glasses for Biomedical Applications

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