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Treatment of scalp malignancies may include the need for craniectomy. The decision to perform cranioplasty is not straightforward and is frequently subjective. The purpose of this study was to assess the clinical outcomes after reconstruction of complex scalp and calvarial defects by comparing patients with and without cranioplasty. Retrospective review of the clinical records of a consecutive series of patients who underwent scalp soft tissue reconstruction after craniectomy for malignancy or osteoradionecrosis between 2014 and 2022 at Royal Melbourne Hospital was conducted. Demographics, previous treatments, surgical details, and post-operative complications were assessed. Traumatic injuries and decompressive craniectomies were excluded. Minimum follow-up of 6 months. Thirty-seven patients were included in the study. Indications for surgery included skin malignancies, osteoradionecrosis, or both. There was one reconstructive failure (in the non-cranioplasty group). Infection and metalware exposure were common complications in patients who underwent cranioplasty (38.5%). No patient developed neurological symptoms subsequent to craniectomy. One patient needed revision surgery due to esthetic reasons (cranioplasty group). Transposition flaps were associated with more complications and revision procedures. Combined scalp and calvarial defects pose a difficult reconstructive challenge. Stable soft tissue coverage is more reliably achieved with free flap reconstruction. Cranioplasty is not always mandatory and should be reserved for cases with a very large bony defect or when the defect is located in a cosmetically sensitive area. [ABSTRACT FROM AUTHOR]

Calvarial defects of bone present difficult clinical situations, and their restoration using biocompatible materials requires special treatments that enable bone regeneration. Magnesium phosphate (MgP) is known as an osteoinductive biomaterial because it contains Mg2+ ions and P ions that enhance the activity of osteoplast cells and help in bone regeneration. In this study, MgP and CuO‐doped MgP were fabricated and characterized for their physicomechanical properties, particle size, morphology, surface area, antibacterial test, and in vitro bioactivity evaluation using the following techniques: X‐rays diffraction, Fourier‐transformer infrared, TEM, and Brunauer, Emmett and Teller (BET) surface area, X‐rays photoelectron spectroscopy (XPS), and Scanning electron microscopy (SEM). Furthermore, these nanopowders were implanted in adult inbred male Wistar rats and studied after two periods (28 and 56 days). The results demonstrated that the obtained semiamorphous powders are in nanoscale (≤ 50 nm). XPS analysis ensured the preparation of MgP as mono MgP and CuO were incorporated in the structure as Cu2+. The bioactivity was supported by the observation of calcium phosphate layer on the nanopowders' surface. The in vivo study demonstrated success of MgP nanopowders especially those doped with CuO in restoration of calvarial defect bone. Therefore, fabricated biomaterials are of great potential in restoration of bone calvarial defects. [ABSTRACT FROM AUTHOR]

Background: Calvarial defect reconstruction can be performed using a wide range of materials which can be divided into autologous and alloplastic options each with their own advantages and disadvantages. Limiting factors of available options include the risk of infection, absorption, cost, and damage to adjacent tissue. Here, we present our experience of calvarial reconstruction using autologous split-rib graft along with technical details of the surgical procedure. Materials and Methods: Our retrospective study included 22 patients over 6 years. All the patients were operated by the same team, and records were maintained. Patients were followed up for at least 2 years. Results: Results achieved were found to be excellent with no major postoperative complications. Patient satisfaction was motivating, and contour of the cranium was acceptable. There was negligible residual or recurrent deformity in our 2-year follow-up. Conclusions: Calvarial reconstruction with autologous bone graft is superior compared to alloplastic materials. Reconstruction with the rib graft gives optimum results which can be used in most clinical scenarios, including pediatric patients.

A soft and highly directive, proximity-coupled split-ring resonator fabricated with a liquid alloy, copper and polydimethylsiloxane (PDMS) is presented. The same was designed for sensing osteogenesis of calvarial bone. As dielectric properties of bone grafts in ossifying calvarial defects should change during the osteogenesis process, devices like this could monitor the gradual transformation of the defect into bone by differentiating changes in the dielectric properties as shifts in the resonance frequency. Computational Software Technology (CST) Microwave Studio®-based simulation results on computational head models were in good agreement with laboratory results on head phantom models, which also included the comparison with an in-vivo measurement on the human head. A discussion based on an inductive reasoning regarding dynamics’ considerations is provided as well. Since the skin elasticity of newborn children is high, stretching and crumpling could be significant. In addition, due to typical head curvatures in newborn children, bending should not be a significant issue, and can provide higher energy focus in the defect area and improve conformability. The present concept could support the development of soft, cheap and portable follow-up monitoring systems to use in outpatient hospital and home care settings for post-operative monitoring of bone healing after reconstructive surgical procedures.

Background: This study presents the evaluation of the damage in the bone tissue resulting from a calvarial defect in rats and the efficiency of exposure to an ozone application with an alloplastic bone graft on the calvarial bone damage.Materials and Methods: Wistar male rats (n = 56) were divided into four groups: a control group (n = 14), defect and ozone group (n = 14), defect and graft group (n = 14), and defect, graft, and ozone group (n = 14). Under anaesthesia, a circular full-thickness bone defect was created in all groups, and the experimental groups were further divided into two sub-groups, with 7 rats in each group sacrificed at the end of the 4th and 8th weeks. Bone samples were dissected, fixed in 10% formalin solution, and decalcified with 5% ethylene-diamine-tetraacetic acid (EDTA). After the routine follow-up on tissues, immunostaining of osteopontin and osteonectin antibodies was applied to sections and observed under a light microscope.Results: The control group exhibited osteopontin and osteonectin expression in fibroblasts and inflammatory cells at the end of the 4th week with an acceleration at the 8th week. Ozone administration elucidated new trabecular bone formation by increasing osteoblastic activity. Lastly, our observations underscore that a combination of allograft and ozone application increased the osteoblast, osteocyte, and bone matrix development at the 4th and 8th weeks.Conclusions: Exposure to an ozone application with an alloplastic bone graft on calvarial bone damage may induce osteoblastic activity, matrix development, mature bone cell formation, and new bone formation in rats. [ABSTRACT FROM AUTHOR]

Commercial bone substitute, such as calcined bovine bone (CBB), is currently extensively used as an alternative to autogenous bone. However, CBB lacks osteoinductivity and merely serves as a scaffold for native bone formation. To address this issue, we designed and prepared a heptaglutamate (E7)‐modified BMP2‐mimicking peptide (7E) and carried out a series of comprehensive physical characterizations and in vivo and in vitro studies to evaluate its role in the repair of cranial defects. The data elucidated that the amount of peptide anchoring to the bone graft materials was remarkably increased after modified with E7. Of note, 7E had a relatively stable and durable release, which promoted the osteogenic differentiation of rat derived bone marrow mesenchymal stem cells (BMSCs) and enhanced the bone regeneration of a rabbit calvarial defect by regulating the expression of the Runx2/SP7 axis. In summary, the composite biomaterials incorporating the E7‐modified BMP2‐mimicking peptide and CBB prepared in this study is a novel bone augmentation material with the merits of non‐immunotoxicity, convenience, and low cost. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:80–93, 2020. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to investigate the influence of particle size of autogenous bone grafts on the early stages of bone regeneration. Materials and Methods: Bicortical skull bone defects were prepared in 15 rabbits (4 in each rabbit). Two defects were filled at random with either small (0.5 to 2 mm³) or large (10 mm³) autogenous bone particles. In addition, 1 defect was left unfilled (control defect). All defects were covered bicortically by expanded polytetrafluoroethylene membranes. The animals were divided randomly into 3 groups and sacrificed after 1, 2, and 4 weeks, respectively. Histologic and stereologic evaluations were performed after the sections were blinded. Results: No significant differences in total vessel surface area could be identified among the 3 groups. The total volume of newly formed bone in defects with small particles was larger and more mature compared to defects with large particles after 2 and 4 weeks. Furthermore, the resorption of small particles was more pronounced after 4 weeks, documenting a higher level of bone substitution compared to large particles. Discussion: The early stages of bone regeneration were influenced by the particle site of autogenous bone grafts. Conclusion: The present study indicated that particles of 0.5 to 2 mm³ in size should be preferred to particles of 10 mm³ in size for bone grafting. [ABSTRACT FROM AUTHOR]

Objective: Bone tissue engineering was introduced in 1995 and provides a new way to reconstruct bone and repair bone defects. However, the design and fabrication of suitable bionic bone scaffolds are still challenging, and the ideal scaffolds in bone tissue engineering should have a three‐dimensional porous network, good biocompatibility, excellent biodegradability and so on. The purpose of our research was to investigate whether a bioplasticpoly3‐hydroxybutyrate4‐hydroxybutyrate (P34HB) electrospun fibre scaffold is conducive to the repair of bone defects, and whether it is a potential scaffold for bone tissue engineering. Materials and methods: The P34HB electrospun fibre scaffolds were prepared by electrospinning technology, and the surface morphology, hydrophilicity, mechanical properties and cytological behaviour of the scaffolds were tested. Furthermore, a calvarial defect model was created in rats, and through layer‐by‐layer paper‐stacking technology, the P34HB electrospun fibre scaffolds were implanted into the calvarial defect area and their effect on bone repair was evaluated. Results: The results showed that the P34HB electrospun fibre scaffolds are interwoven with several fibres and have good porosity, physical properties and chemical properties and can promote cell adhesion and proliferation with no cytotoxicity in vitro. In addition, the P34HB electrospun fibre scaffolds can promote the repair of calvarial defects in vivo. Conclusions: These results demonstrated that the P34HB electrospun fibre scaffold has a three‐dimensional porous network with good biocompatibility, excellent biosafety and ability for bone regeneration and repair; thus, the P34HB electrospun fibre scaffold is a potential scaffold for bone tissue engineering. [ABSTRACT FROM AUTHOR]

In this pilot study, we aim to investigate the clinical efficacy of a novel polycaprolactone-tricalcium phosphate (PCL-TCP) membrane for guided bone regeneration (GBR) in an in vivo model. Eight rabbits, each with two surgically created calvarial defects were reconstructed using a bovine particulate bone substitute, then covered with a mechanical barrier using a PCL-TCP or collagen membrane, or left uncovered without any membrane. The rabbits were sacrificed at 1 and 2 months and the reconstructed defects were harvested for histology and histomorphometry evaluations. Results showed no statistical significance in percentage bone area fraction (BAF%) between the PCL-TCP and collagen membranes at 1 and 2 months. The BAF% of the PCL-TCP membrane group was statistically higher at 2 months compared to 1 month (p < .05) ; the BAF% in the collagen membrane group did not increase significantly from the first to second months ( p > .05) . We postulate that this is attributed to the greater stiffness and slower degradation of PCL-TCP. We conclude that the novel PCL-TCP membrane is as effective as the commercially available collagen membrane as a mechanical barrier for GBR, with good handling characteristics. Future work should explore variations in PCL-TCP composition to further improve its usability and rate of desired degradation. [ABSTRACT FROM AUTHOR]

Developing low-cost nano-biomaterials using locally available raw materials is gaining significant prominence recently, e.g., to meet the UN's sustainable development goals (Goal 3). In this work, amorphous calcium silicate (CaS) nanopowders were prepared from Egyptian corals (CaCO 3) as a low-cost bone restoration material due to their excellent bonding abilities with surrounding bone tissues, which in turn accelerated the bone healing process. Some of the developed CaS nanopowders was doped with different concentrations of Cu2+ and Zn2+ at the expense of the inherent Ca2+ in the raw materials. The nanopowders were characterized using X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), scanning electron microscope with energy-dispersive X-ray spectrometry (SEM-EDX), transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET) surface area measurements. Mechanical and bactericidal properties of the nanopowders were assessed followed by well-defined examinations of their abilities to support cell viability, proliferation and differentiation against osteosarcoma cells (MG63 cell lines). The obtained nanopowders were confirmed to be amorphous in nature with particle diameters mostly in two size ranges, namely, 5–10 nm and 15–92 nm. The nanopowders were found to have a good surface area influenced by the type of dopant materials. Notable enhancement in the mechanical (up to 6.76 MPa compressive strength) and antibacterial behaviors of the CaS nanopowders were observed after Zn2+ doping. The number of the differentiated cells after 72 h of incubation was increased, especially for CaS silicate Zn2+ doped nanopowders. Following these examinations of the nanopowders, their utility for the treatment of calvarial (top part of the skull) defects in a rat model was investigated. The developed Cu2+ or Zn2+ doped nanopowders enhanced the healing rate of calvarial defects and they demonstrated impressive biosafety towards repairing vital organs (brain, liver and kidney). [Display omitted] • Low-cost calcium silicate (CaS) nanopowders free and doped with Cu or Zn were successfully prepared using chemical precipitation method. • The doping has enhanced the mechanical, antibacterial and cell proliferations behaviours of the CaS nanopowders. • Calvarial defects healing were increased in the presence of dopant materials Cu or Zn without detection of any harmful effects on the vital organs. [ABSTRACT FROM AUTHOR]

Introduction: Efforts are being made to improve the efficacy of biomaterials used as bone substitutes for bone regeneration in the oral and maxillofacial region. Graft materials have been recently produced in Iran; however, studies are required to confirm their efficacy. This study aimed to compare the histomorphometric results of using mineralized allografts produced by the Hamanandsaz Baft Kish Company and the Iranian Tissue Bank (ITB) for regeneration of rabbit calvarial bone defects. Materials and Methods: In this animal study, four similar holes with a minimum diameter of 6.5 mm were created in the calvaria of 14 white New Zealand rabbits. The defects were filled with Cenobone (Hamanandsaz Baft Kish Co.), ITB product and Cerabone (Botiss Co). One defect remained unfilled as the control group. One and two months after implantation, the animals were sacrificed and the defects was subjected to histologic and histomorphometric assessments. The amount of new bone formation and the volume of remaining biomaterials were analyzed using one-way ANOVA. The inflammatory reaction was analyzed by the Kruskal Wallis test and the foreign body reaction, bone quality and bone-graft interface pattern were analyzed using the Fisher’s exact test. Results: The amount of new bone formation was 0.060.1± and 0.11± 0.1, 0.040.08± and 0.110.09±, and 0.080.12± and 0.090.06± mm2 in the ITB, Cerabone and Cenobone groups at one and two months post-implantation, respectively. The effect of time and type of biomaterial on the amount of new bone formation was not significant. At one month, significant differences were seen in the amount of remaining biomaterials in the defects among the three groups (P

Bone damage and accidents, traumas can alter people's normal life, and damage the soft tissues. In this study, we aimed to investigate in calvarial defects in rats depending on the severity of cerebral contusion injury occurring in the temporal region. The rats were randomly divided into two groups: group 1 (control group), critical size cranial model with no treatment (n= 10); group 2 (14-day synthetic graft group given 7th day DEXA), critical size cranial model treated with Dexamethasone (0.05 mg/kg intramuscular injection) +Synthetic graft (n= 10) One calvarium defect of 7 mm was made in the parietal bone of each animal under general anesthesia. Calvarial defect results in dilatation of blood vessels, hemorrhage and deterioration was observed in glial fibrillary structures. Additionally, the increase in vascular endothelial growth factor expression showed a positive reaction with glial fibrillary acid protein astrocytes extensions. Apoptotic glial cells stained positive with Bcl-2. Calvarial defects caused by mild brain injury, to be induced by inflammatory cytokines, interrupting glial fibrillary degeneration by affecting the blood brain barrier is thought to promote apoptotic changes. [ABSTRACT FROM AUTHOR]

Objective Stem cell therapies may be applicable to all fields of medicine, including craniomaxillofacial surgery. Dental pulp stem cells also have significant osteogenic properties. This study aimed to evaluate the influence of dental pulp stem cells on bone regeneration and to ascertain whether or not there was any superiority over traditional methods. Design In this study, 15 non-immunodeficient Wistar albino rats were used. The rats were divided into three groups: (1) untreated control group; (2) hydroxyapatite tri-calcium-phosphate (HA/TCP) paste; (3) human dental pulp derived stem cells (DPSC) mixed with HA/TCP paste (HA/TCP+DSPC group, n = 10). Two symmetrical full-thickness cranial defects were created on each parietal region (10 defects for each group). The animals were sacrificed 8 weeks post-surgery and samples were analyzed by microcomputer tomography (μ-CT) and histomorphometry. Results The calcification rate and bone mineral density (BMD) values in Group 3 were found to be significantly higher than in the other two groups. Radiographically, bone regeneration was greater in Group 2 compared with the control group. However, there was no significant difference between Groups 2 and 1 in respect of histological analysis. Conclusions According to the results of the present study, DPSCs may be a suitable factor for bone tissue engineering because they can be easily obtained and differentiate into bone cells. [ABSTRACT FROM AUTHOR]

The rat calvarial defect is an established model to evaluate craniofacial bone regeneration using cell-scaffold biocomplexes. Dental pulp harbors stem cells with significant osteogenic properties. Extracellular matrix (ECM)-like scaffolds simulate the environment that cells observe in vivo . In the present study, we evaluated the osteogenic effect of a biocomplex of human dental pulp cells and a hyaluronic-based hydrogel scaffold in calvarial defects of immunocompetent rats. Dental pulp cells at the 2nd passage were characterized by flow cytometry, osteodifferentiated ex vivo for 4 days and the whole population was encapsulated in the synthetic ECM matrix. Cell vitality was verified 24 h upon encapsulation. 5 mm calvarial defects were created in 30 male rats and filled with the biocomplex, the scaffold alone, or left untreated. Histological evaluation at 8 weeks showed incomplete bone regeneration in all groups. The scaffold was not fully degraded and entrapped cells were detected in it. Histomorphometry showed statistically significant superior new bone formation in the biocomplex-treated group, compared to the two other groups. The present study provides evidence that the whole population of human dental pulp cells can advance bone healing when transplanted in immunocompetent animals and highlights the importance of proper scaffold degradation in cell-driven bioengineering treatments. [ABSTRACT FROM AUTHOR]

We have investigated the combination effects of bioceramics and poly(lactide-co-glycolide) (PLGA) on bone reconstruction in calvarial critical size defects using a rat model. Willemite (Zn2SiO4) ceramics were prepared and coated on the surface of electrospun fabricated scaffolds. After scaffolds and nanoparticles characterization, osteoconductivity of the construct was analyzed using digital mammography, multislice spiral-computed tomography (MSCT) imaging, and histological analysis. Eight weeks after implantation, no sign of inflammation was observed at the site of the osseous defect. The results showed that the ceramics supported bone regeneration and highest bone reconstruction were observed in willemite-coated PLGA. This suggests that electrospun PLGA nanofibers coated with BG are potential candidate implants for bone tissue engineering applications. [ABSTRACT FROM AUTHOR]

Induced pluripotent stem cells (iPSCs) have great potential in bone tissue engineering to repair large bone defects. Before their clinical application, investigations are needed to discover the genes and osteoconductive scaffolds that influence their differentiation toward an osteogenic lineage. Alox5 plays controversial and complex roles in the regulation of bone and fat metabolism. To detect the effect of Alox5 on osteogenic and adipogenic differentiation of iPSCs, both Alox5 knockout mouse iPSCs ( Alox5-KO-iPSCs) and wild-type mouse iPSCs (Wild-iPSCs) were developed. The mRNA levels of many osteogenic markers in Alox5-KO-iPSCs were significantly reduced, while many adipogenic markers were enhanced. Furthermore, when implanted in rat cranial critical-sized defects with collagen/chitosan/hydroxyapatite scaffolds (CCHS), Alox5-KO-iPSCs produced significantly less new bone than Wild-iPSCs and both cell-scaffold groups had no tumor formation. There was a significant difference in the expression of Cox2 during the osteogenic and adipogenic differentiation between the two kinds of iPSCs in vitro. In conclusion, firstly, Alox5 knockout reduced the osteogenic but increased the adipogenic differentiation potential of mouse iPSCs. These disorders might be related to the change of Cox2 expression. Secondly, combined with iPSCs, CCHS can serve as a potential substrate to repair critical-sized bony defects. However, more studies are required to confirm the mechanisms through which Alox5 affects the osteogenic and adipogenic abilities of iPSCs in vivo and the effect of Cox2 inhibition in this system. [ABSTRACT FROM AUTHOR]

Sirtuin 6 (SIRT6) is a NAD-dependent deacetylase involved in lifespan regulation. To evaluate the effect of SIRT6 on osteogenesis, rat bone marrow mesenchymal stem cells (rBMSCs) with enhanced or reduced SIRT6 function were developed. We observed that SIRT6 knockdown significantly reduced the mRNA levels of several key osteogenic markers in vitro, including alkaline phosphatase (ALP), Runt-related transcription factor 2 (RUNX2), and osteocalcin, while overexpression of SIRT6 enhanced their expression. Additionally, SIRT6 knockdown activated nuclear factor-κB (NF-κB) transcriptional activity and upregulated the expression of acetyl-NF-κB p65 (Lys310). The decreased osteogenic differentiation ability of rBMSCs could be partially rescued by the addition of NF-κB inhibitor BAY 11-7082. Furthermore, SIRT6 overexpression in rBMSCs combined with the use of collagen/chitosan/hydroxyapatite scaffold could significantly boost new bone formation in rat cranial critical-sized defects, as determined by microcomputed tomography and histological examination. These data confirm that SIRT6 is mainly located in the nuclei of rBMSCs and plays an essential role in their normal osteogenic differentiation, partly by suppressing NF-κB signaling. S tem C ells 2014;32:1943-1955 [ABSTRACT FROM AUTHOR]

Tissue engineering with a combination of stem cells and nanofibrous scaffolds has attracted interest with regard to bone regeneration applications. In the present study, human induced pluripotent stem cells (iPSCs) were cultured on polymeric nanofibrous polyethersulfone (PES) with and without plasma treatment. The capacity of PES and plasma-treated PES (Plasma-PES) scaffolds to support the proliferation and osteogenic differentiation of iPSCs was investigated by MTT assay and for common osteogenic markers such as alkaline phosphatase activity, calcium mineral deposition and bone-related genes. Plasma-PES scaffolds with or without iPSCs were subsequently used to evaluate bone regeneration of critical-size defects in the rat by digital mammography, multislice spiral-computed tomography imaging and histological analysis. The results of in vitro analysis showed that plasma treatment significantly enhanced iPSC proliferation and osteogenesis. After 8 weeks of iPSC-loaded Plasma-PES implantation, no mortality or complication was observed in animals or at the site of surgery. Imaging analysis revealed more extensive bone reconstruction in rats receiving nanofibers compared with untreated control groups. Moreover, Plasma-PES seeded with iPSCs induced the highest regeneration of bone defects among all groups. These findings were confirmed by histological staining. Affective osseointegration was observed in implanted scaffolds. Thus, plasma-treated nanofibrous scaffolds are suitable tissue-engineered matrices for supporting the proliferation and osteogenic differentiation of iPSCs and might also be appropriate for the reconstruction of bone defects. [ABSTRACT FROM AUTHOR]

Abstract: A flexible and fibrous composite scaffold composed of poly(ε-caprolactone)–poly(ethylene glycol)–poly(ε-caprolactone) (PCL–PEG–PCL, PCEC) and 30 wt.% nano-hydroxyapatite (n-HA) was fabricated through electrospinning. In the present study, we investigated its in vitro and in vivo performance by means of hydrolytic degradation, muscle pouch implantation, as well as repair the calvarial defects in New Zealand white rabbits. The results demonstrated that the degradable scaffold held good biocompatibility. Qualitative analysis of bone regeneration process was performed by radiological examination and histological analysis. The results indicated that new bone formed originally from the margin of host bone, and then grew toward the center of defects. Moreover, the quantitative determination of newly formed bone was performed using statistical analysis of histological sections at predetermined time points. At 20th week, the defects of treatment group were covered with the new solid cortical bone. In comparison, the control group was filled with a large amount of cancelous bone and bone marrow. It suggested that the composite scaffold had better activity of guided bone regeneration than that of self-healing. So the electrospun PCEC/n-HA fibrous scaffold had the great potential application in bone tissue engineering. [Copyright &y& Elsevier]

Over 500,000 bone graft or bio-implant procedures are performed annually in the United States. It has been reported that osseous autograft procurement may result in donor site complications and bio-implant allografts have been associated with disease transmission. Ceramic scaffolds are only osteoconductive, limiting their clinical use. The objective of this study was to create a bone filler substitute with regenerating properties similar to natural bone. Therefore, melatonin and platelet-rich plasma (PRP) were utilized for their known osteoinductive properties. It was hypothesized that melatonin and/or PRP would enhance the osteoinductive and osteoconductive properties of calcium aluminate (CA) scaffolds to promote bone regeneration in a model of calvarial defects. The biocompatibility of CA and CA-Mel scaffolds was tested in vitro and in vivo. Data show that CA-Mel scaffolds, in comparison with CA scaffolds, enhanced the adhesion, viability, and proliferation of normal human osteoblasts cells but not that of NIH3T3 fibroblasts. Data also showed that human adult mesenchymal stem cells grown on CA or CA-Mel scaffolds showed a time-dependent induction into osteoblasts over 14 days revealed through scanning electron microscopy and by alkaline phosphatase analyses. Implantation of CA-Mel scaffolds into critical size calvarial defects in female, ovariectomized rats showed that the CA-Mel scaffolds were biocompatible, allowed for tissue infiltration, and showed evidence of scaffold biodegradation by 3 and 6 months. Bone regeneration, assessed using fluorochrome labeling at 3 and 6 months, was greatest in animals implanted with the CA-Mel scaffold. Overall, results from this study show that CA-Mel scaffolds were osteoconductive and osteoinductive. [ABSTRACT FROM AUTHOR]

To realize the therapeutic potential of mesenchymal stem cells (MSCs), we aimed to develop a method for isolating and expanding New Zealand rabbit MSCs in a great scale. Rabbit MSCs expanded under hypoxic and normoxic conditions were compared in terms of replication capacity, differentiation potential, and the capacity for allogeneic transplantation in a calvarial defect model. The cells from all tested rabbits were expanded more rapidly when plated at low-density under hypoxic conditions compared to under normoxic conditions. Moreover, cells expanded under hypoxic conditions increased in the potential of osteoblastic, adipocytic, and chondrocytic differentiation. More importantly, radiographic analysis and micro-CT measurement of bone volume revealed the hypoxic cells when transplanted in the calvarial defects of another rabbit increased in the ability to repair bone defect compared to the normoxic cells. Six weeks after allogeneic transplantation of hypoxic MSCs, histological analysis revealed a callus spanned the length of the defect, and several bone tissues spotted in the implant. At 12 weeks, new bone had formed throughout the implant. Using BrdU labeling to track the transplanted cells, the hypoxic cells were more detected in the newly formed bone compared to the normoxic cells. For defects treated with allogeneic MSCs, no adverse host response could be detected at any time-point. In conclusion, we have developed a robust method for isolation and expansion of rabbit MSCs by combining low-density with hypoxic culture, which can be applied for the design of clinical trials in allogeneic transplantation of MSCs for bone healing. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1213-1220, 2012 [ABSTRACT FROM AUTHOR]

Abstract: Subject: The advanced tumors of the scalp can involve the calvarium, the dura and the cerebral tissue. The medium sized full thickness scalp defects secondary to the excision of such cutaneous malignancy can be successfully treated with local flaps coming from the remaining scalp if these flaps are large and including at least one major pedicle of the scalp. The cranioplasty can be done immediately or secondarily. Patients and methods: From May 2001 to July 2006, 21 patients aged between 52 and 78 years old, suffering from advanced basal and squamous cell carcinomas with invasion of the calvarium in all cases, the dura in 1 case and the cerebral tissue in 2 cases have benefited from an excision of the scalp and calvarium with a margin between 1 and 3 cm. The secondary defects measured between 9 and 15 cm for the scalp and between 6 and 9 cm for the calvarium. In 1 case, the dura was resected and reconstructed with a fascia lata graft. The flaps used were: a single pedicled transposition flap based on one or two occipital pedicles in 10 cases — a bipedicled transposition flap based on the superficial temporal pedicles in 3 cases and on the frontal and occipital pedicles in 4 cases — a large rotation flap in 4 cases. These flaps were undermined under the galea without any galeotomies. Their donor sites were immediately grafted. The calvarium was reconstructed by a methylmetacrylate implant in 9 cases, simultaneously with these flaps in 4 cases and secondarily in 5 cases. Results: There were no vascular problems in all these flaps — 3 cases of infection in the simultaneous reconstruction of the scalp and calvarium are reported. The two patients with cerebral invasion are deceased 1 year after the surgery. The other patients are still alive without any recurrence or metastasis with a mean follow-up of 36 months. Conclusion: Such complex defects of the tumoral scalp can be reconstructed with large and axial local flaps of the remaining scalp with safety. The cranioplasty has to be delayed. [Copyright &y& Elsevier]

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The purpose of the present study was to determine the best implant material, the best conditions to substitute absorbable membrane for non-absorbable membrane, and the factors influencing guided regeneration of critical size defects using experimental rats. An 8-mm circular transosseous calvarial bony defect was made and implant materials, such as demineralized freeze-dried bone (DFDB), absorbable membrane (BioMesh; Samyang Co., Seoul Korea), non-absorbable membrane (Millipore filter; Micro Filtration System, MA, USA) or a combination of these materials, was placed on the defect. As for the results of sequential time-based guided bone regeneration, histological, histochemical, immunohistochemical and histomorphometric aspects were observed, and a statistical comparative analysis was performed, with control group of a soft tissue flap. Bone formation was significantly enhanced when DFDB was retained within the defect with a protective absorbable membrane. Inframembranous DFDB-filling was required to prevent membrane collapse and to preserve spaces for bone regeneration. The absorbable membrane which was recommended to overcome the disadvantages of the non-absorbable membrane should remain intact for more than 5 weeks in order for it to be effective. The macrophages recruited by grafts were involved partly in decreasing bone regeneration via the sequential events of releasing fibronectin, and in chemotactic effect of the fibronectin to fibroblasts and collagen lay-down. Thus, the activity of new bone formation was dependent upon the physical barrier effect of the membrane, such as the preserving ability to secure spaces and the suppression ability of early infiltration of collagen and epithelium, inducible ability of inflammation by the implant material, and potential in guiding bone regeneration of the grafts. [ABSTRACT FROM AUTHOR]

Rare type of calvarial defects seen in patients with neurofibromatosis type-1 (NF1) is presented. The issues of pathogenesis and management are discussed. Two cases of NF1 with skull defects in the region of the lambdoid suture are reported. The possible etiological basis and nature of these type of defects and management issues are discussed. The calvarial skull defects in the lambdoid suture region are rare defects in NF1 patients. The possible reason of the progressive nature of these type of lesions can be the cerebrospinal fluid pulsations behaving like "growing skull fractures," especially when not associated with structural lesions. It leads to progressive enlargement of the small congenital defects in the region of the lambdoid suture and abnormal susceptibility of bones for resorption. For these defects, conservative management is suggested due to its progressive nature and high chances of operative treatment failure. [ABSTRACT FROM AUTHOR]

Recently, stem cell-based bone tissue engineering (BTE) has been recognized as a preferable and clinically significant strategy for bone repair. In this study, a pure 3D silk fibroin (SF) scaffold was fabricated as a BTE material using a lyophilization method. We aimed to investigate the efficacy of the SF scaffold with and without seeded human adipose-derived mesenchymal stem cells (hASCs) in facilitating bone regeneration. The effectiveness of the SF-hASCs scaffold was evaluated based on physical characterization, biocompatibility, osteogenic differentiation in vitro, and bone regeneration in critical rat calvarial defects in vivo. The SF scaffold demonstrated superior biocompatibility and significantly promoted osteogenic differentiation of hASCs in vitro. At six and twelve weeks postimplantation, micro-CT showed no statistical difference in new bone formation amongst all groups. However, histological staining results revealed that the SF-hASCs scaffold exhibited a better bone extracellular matrix deposition in the defect regions compared to other groups. Immunohistochemical staining confirmed this result; expression of osteoblast-related genes (BMP-2, COL1a1, and OCN) with the SF-hASCs scaffold treatment was remarkably positive, indicating their ability to achieve effective bone remodeling. Thus, these findings demonstrate that SF can serve as a potential carrier for stem cells, to be used as an osteoconductive bioscaffold for BTE applications. [ABSTRACT FROM AUTHOR]

A soft and highly directive, proximity-coupled split-ring resonator fabricated with a liquid alloy, copper and polydimethylsiloxane (PDMS) is presented. The same was designed for sensing osteogenesis of calvarial bone. As dielectric properties of bone grafts in ossifying calvarial defects should change during the osteogenesis process, devices like this could monitor the gradual transformation of the defect into bone by differentiating changes in the dielectric properties as shifts in the resonance frequency. Computational Software Technology (CST) Microwave Studio®-based simulation results on computational head models were in good agreement with laboratory results on head phantom models, which also included the comparison with an in-vivo measurement on the human head. A discussion based on an inductive reasoning regarding dynamics' considerations is provided as well. Since the skin elasticity of newborn children is high, stretching and crumpling could be significant. In addition, due to typical head curvatures in newborn children, bending should not be a significant issue, and can provide higher energy focus in the defect area and improve conformability. The present concept could support the development of soft, cheap and portable follow-up monitoring systems to use in outpatient hospital and home care settings for post-operative monitoring of bone healing after reconstructive surgical procedures.

Background: In the field of bone tissue engineering, there has been an increasing interest in biomedical materials with both high angiogenic ability and osteogenic ability. Among various osteogenesis materials, bioactive borosilicate and borate glass scaffolds possess suitable degradation rate and mechanical strength, thus drawing many scholars' interests and attention., Objective: In this study, we fabricated bioactive glass scaffolds composed of borosilicate 2B6Sr using the Template-Method and incorporated Dimethyloxalylglycine (DMOG), a small-molecule angiogenic drug possessing good angiogenic ability, to improve bone regeneration., Methods: The in-vitro studies showed that porous borosilicate bioactive glass scaffolds released slowly, a steady amount of DMOG and stimulated the proliferation and osteogenic differentiation of human bone marrow stromal cells hBMSCs., Results: In-vivo studies showed that the borosilicate bioactive glass scaffolds could significantly promote new bone formation and neovascularization in rats' calvarial bone defects., Conclusion: These results indicated that DMOG-incorporated bioactive glass scaffold is a successful compound with excellent angiogenesis-osteogenesis ability, which has favorable clinical prospects., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

A novel three-dimensional biomimetic porous microsphere was successfully designed in this study, which was composed of PDLLA, bone marrow mesenchymal stem cells (MSCs), and nanohydroxyapatite (nHAp). nHAp/PDLLA/MSC porous microspheres that are supposed to be a significant constituent of bone in vertebrate were prepared to act as biodegradable support materials. In addition, bone MSCs act as seeding cells in bone defect repair. The microstructure of the obtained nHAp/PDLLA/MSC porous microspheres was characterized. Scanning electronic microscopy showed that the composite materials exhibited a cross-linked porous structure. In vivo biocompatibility was studied by the way of implanting the nHAp/PDLLA porous microspheres subcutaneously in rats for 4 and 8 weeks. In addition, the osteogenic capacity of the nHAp/PDLLA/MSC porous microspheres was assessed by implanting the 10 mm × 10 mm × 3 mm cranial defect of New Zealand white rabbits. In vivo studies confirmed that nHAp/PDLLA/MSC porous microspheres had a good biocompatibility and were better in inducing bone regeneration than nHAp/PDLLA porous microspheres and the self-healing process. All of the results suggested that the nHAp/PDLLA/MSC porous microspheres present a remarkable potential in calvarial defect repair and bone tissue engineering.