Concentrated growth factor regulates the macrophage-mediated immune response

Concentrated growth factor(CGF)is a promising regenerative material that serves as a scaffold and adjunct growth factor for tissue engineering.The host immune response,particularly macrophage activity,plays a critical role in injury repair and tissue regeneration.However,the biological effect of CGF on the immune response is not clear.To enrich the theoretical groundwork for clinical application,the present study examined the immunoregulatory role of CGF in macrophage functional activities in vitro.The CGF scaffold appeared as a dense fibrin network with multiple embedded leukocytes and platelets,and it was biocompatible with macrophages.Concentrated bioactive factors in the CGF extract enhanced THP-1 monocyte recruitment and promoted the maturation of suspended monocytes into adherent macrophages.CGF extract also promoted THP-1 macrophage polarization toward the M2 phenotype with upregulated CD163 expression,as detected by cell morphology and surface marker expression.A cytokine antibody array showed that CGF extract exerted a regulatory effect on macrophage functional activities by reducing secretion of the inflammatory factor interleukin-1b while inducing expression of the chemokine regulated on activation,normal T cell expressed and secreted.Mechanistically,the AKT signaling pathway was activated,and an AKT inhibitor partially suppressed the immunomodulatory effect of CGF.Our findings reveal that CGF induces a favorable immune response mediated by macrophages,which represents a promising strategy for functional tissue regeneration.

Porous polyetheretherketone microcarriers fabricated via hydroxylation together with cellderived mineralized extracellular matrix coatings promote cell expansion and bone regeneration

Porous microcarriers have aroused increasing attention recently by facilitating oxygen and nutrient transfer,supporting cell attachment and growth with sufficient cell seeding density.In this study,porous polyetheretherketone(PEEK)microcarriers coated with mineralized extracellular matrix(mECM),known for their chemical,mechanical and biological superiority,were developed for orthopedic applications.Porous PEEK microcarriers were derived from smooth microcarriers using a simple wet-chemistry strategy involving the reduction of carbonyl groups.This treatment simultaneously modified surface topology and chemical composition.Furthermore,the microstructure,protein absorption,cytotoxicity and bioactivity of the obtained porous microcarriers were investigated.The deposition of mECM through repeated recellularization and decellularization on the surface of porous MCs further promoted cell proliferation and osteogenic activity.Additionally,the mECM coated porous microcarriers exhibited excellent bone regeneration in a rat calvarial defect repair model in vivo,suggesting huge potential applications in bone tissue engineering.

Dental pulp stem cells and BonelikeVR for bone regeneration in ovine model

Development of synthetic bone substitutes has arisen as a major research interest in the need to find an alternative to autologous bone grafts.Using an ovine model,the present pre-clinical study presents a synthetic bone graft(BonelikeVR)in combination with a cellular system as an alternative for the regeneration of non-critical defects.The association of biomaterials and cell-based therapies is a promising strategy for bone tissue engineering.Mesenchymal stem cells(MSCs)from human dental pulp have demonstrated both in vitro and in vivo to interact with diverse biomaterial systems and promote mineral deposition,aiming at the reconstruction of osseous defects.Moreover,these cells can be found and isolated from many species.Non-critical bone defects were treated with BonelikeVR with or without MSCs obtained from the human dental pulp.Results showed that BonelikeVR and MSCs treated defects showed improved bone regeneration compared with the defects treated with BonelikeVR alone.Also,it was observed that the biomaterial matrix was reabsorbed and gradually replaced by new bone during the healing process.We therefore propose this combination as an efficient binomial strategy that promotes bone growth and vascularization in non-critical bone defects.

Effects of pore interconnectivity on bone regeneration in carbonate apatite blocks

Porous architecture in bone substitutes,notably the interconnectivity of pores,is a critical factor for bone ingrowth.However,controlling the pore interconnectivity while maintaining the microarchitecture has not yet been achieved using conventional methods,such as sintering.Herein,we fabricated a porous block using the crystal growth of calcium sulfate dihydrate,and controlled the pore interconnectivity by limiting the region of crystal growth.The calcium sulfate dihydrate blocks were transformed to bone apatite,carbonate apatite(CO_(3)Ap)through dissolution–precipitation reactions.Thus,CO_(3)Ap blocks with 15%and 30%interconnected pore volumes were obtained while maintaining the microarchitecture:they were designated as CO_(3)Ap-15 and CO_(3)Ap-30,respectively.At 4 weeks after implantation in a rabbit femur defect,new bone formed throughout CO_(3)Ap-30,whereas little bone was formed in the center region of CO_(3)Ap-15.At 12 weeks after implantation,a large portion of CO_(3)Ap-30 was replaced with new bone and the boundary with the host bone became blurred.In contrast,CO_(3)Ap-15 remained in the defect and the boundary with the host bone was still clear.Thus,the interconnected pores promote bone ingrowth,followed by replacement of the material with new bone.These findings provide a useful guide for designing bone substitutes for rapid bone regeneration.

Platelet-rich plasma combined with injectable hyaluronic acid hydrogel for porcine cartilage regeneration: a 6-month follow-up

Based on our previous study,the utilization of an ultraviolet light photo-cross-linkable hyaluronic acid(HA)hydrogel integrated with a small molecule kartogenin-encapsulated nanoparticles obtained good reconstruction of osteochondral defects in a rabbit model,indicating the superiority of injectable hydrogel-based scaffolds in cartilage tissue engineering.Platelet-rich plasma(PRP),rich in various growth factors,proteins and cytokines,is considered to facilitate cartilage healing by stimulating cell proliferation and inducing chondrogenesis in cartilage defect site.The aim of this study was to test the therapeutic feasibility of autologous PRP combined with injectable HA hydrogel on cartilage repair.The focal cartilage defects with different critical sizes in the medial femoral condyle of a porcine model were used.At 6 months,the minipigs were sacrificed for assessment of macroscopic appearance,magnetic resonance imaging,micro-computed tomography,histology staining and biomechanics.The HA hydrogel combined with PRP-treated group showed more hyaline-like cartilage exhibited by macroscopic appearance and histological staining in terms of extracellular matrix and type II collagen without formation of hypertrophic cartilage,indicating its capacity to improve cartilage healing in the minipig model evaluated at 6 months,with full-thickness cartilage defect of 8.5mm diameter and osteochondral defect of 6.5mm diameter,5mm depth exhibiting apparent regeneration.

Application of PMMA bone cement composited with bone-mineralized collagen in percutaneous kyphoplasty

We investigated the feasibility of applying polymethylmethacrylate bone cement composited with biomimetic bone-mineralizsed collagen to percutaneous kyphoplasty(PKP).We performed PKP in 95 patients diagnosed with osteoporotic vertebral compression fracture.All patients had fractures of a single vertebral body,and they were divided randomly into control(group A,47 patients)and experimental(group B,48 patients)groups.Patients in group A were treated with acrylic cement,and those in group B were treated with acrylic cement composited with the bone graft material.All patients were evaluated by a visual analogue scale(VAS),Oswestry disability index(ODI),Cobb angle and anterior vertebral body height preoperatively,and 3 days and 3 months postoperatively.All patients successfully completed surgery and were followed up thereafter.The VAS score,ODI index,Cobb angle and anterior vertebral body height compression rate in both groups had significant changes(P<0.05)preoperatively,and at 3 days and 3 months postoperatively.There was no significant difference between the two groups at different times(P>0.05).The analgesic effects of bone cement composited with bone-mineralized collagen are similar to those of bone cement only.Mineralized collagen has excellent promotion prospects by inducing new bone formation and reducing the incidence of adverse reactions caused by bone cement.

Effect of intraplaque angiogenesis to atherosclerotic rupture-prone plaque induced by high shear stress in rabbit model

Atherosclerotic prone-rupture plaque is mainly localized in the region of the entrance to the stenosiswith high shear stress and the reasons are largely unknown. Our hypothesis is that such a distributionof cells in atherosclerotic plaque may depend on the angiogenesis. Silastic collars inducedregions of high shear stress (20.6865.27 dynes/cm2) in the upstream flow and low shear stress(12.2561.28 dynes/cm2) in the downstream flow in carotid arteries. Compared with the low shearstress region, plaques in the high shear stress region showed more intraplaque haemorrhaging,less collagen and higher apoptotic rates of vascular smooth muscle cells;endothelial cells (ECs) inthe high shear stress region were characterized with integrity and high endothelial nitric oxidesynthase (eNOS) expression (1570.36345.5% vs 172.9649.9%). The number of intraplaque microvesselsis very high in the high shear stress region (1561.8 n/mm2 vs 3.560.4 n/mm2), and themicrovessels in the plaque show ECs were abnormal, with membrane blebs, intracytoplasmic vacuolesand leukocyte infiltration. Our current study reveals that the integrity of the endothelium andthe vulnerability of atherosclerotic plaques are simultaneously localized in high shear stress regions,and we provide evidence for the first time that microvessels in the intraplaque maybe responsiblefor rupture-prone plaque formation in the high shear stress region.

Bioinspired laminated bioceramics with high toughness for bone tissue engineering

For the research of biomaterials in bone tissue engineering,it is still a challenge to fabricate bioceramics that overcome brittleness whilemaintaining the great biological performance.Here,inspired by the toughness of naturalmaterials with hierarchical laminated structure,we presented a directional assembly-sintering approach to fabricate laminated MXene/calcium silicate-based(L-M/CS)bioceramics.Benefiting from the orderly laminated structure,the LM/CS bioceramics exhibited significantly enhanced toughness(2.23MPa·m^(1/2))and high flexural strength(145MPa),which were close to the mechanical properties of cortical bone.Furthermore,the L-M/CS bioceramics possessed more suitable degradability than traditional CaSiO_(3)bioceramics due to the newly formed CaTiSiO_(5)after sintering.Moreover,the L-M/CS bioceramics showed good biocompatibility and could stimulate the expression of osteogenesisrelated genes.The mechanism of promoting osteogenic differentiation had been shown to be related to theWnt signaling pathway.This work not only fabricated calciumsilicate-based bioceramics with excellentmechanical and biological properties for bone tissue engineering but also provided a strategy for the combination of bionics and bioceramics.

Application of osteoinductive calcium phosphate ceramics in giant cell tumor of the sacrum:report of six cases

This study aimed at evaluating the possibility and effectiveness of osteoinductive bioceramics to fill the tumor cavity following the curettage of sacral giant cell tumor(GCT).Six patients(four females and two males,25–45 years old)underwent nervesparing surgery,in which the tumor was treated by denosumab,preoperative arterial embolization and extensive curettage.The remaining cavity was filled with commercial osteoinductive calcium phosphate(CaP)bioceramics,whose excellent osteoinductivity was confirmed by intramuscular implantation in beagle canine.All patients were followed by computed tomography(CT)scans postoperatively.According to the modified Neer criterion,five cases obtained Type I healing status,and one case had Type II.At the latest follow-up,no graft-related complications and local recurrence were found.The CT scan indicated a median time of healing initiation of 3months postoperatively,and the median time for relatively complete healing was 12months.The excellent bone regenerative ability of the ceramics was also confirmed by increased CT attenuation value,blurred boundary and cortical rim rebuilding.In conclusion,osteoinductive CaP bioceramics could be an ideal biomaterial to treat the large remaining cavity following extensive curettage of sacral GCT.However,further investigation with more cases and longer follow-up was required to confirm the final clinical effect.

Biomimetic polyetheretherketone microcarriers with specific surface topography and self-secreted extracellular matrix for large-scale cell expansion

Reusable microcarriers with appropriate surface topography,mechanical properties,as well as biological modification through decellularization facilitating repeated cell culture are crucial for tissue engineering applications.Herein,we report the preparation of topological polyetheretherketone(PEEK)microcarriers via gas-driven and solvent exchange method followed by hydrothermal treatment at high temperature and pressure.After hydrothermal treated for 8 h,the resulting topological PEEK microcarriers exhibit walnut-like surface topography and good sphericity as well as uniform size distribution of 350.24619.44 mm.And the average width between ravine-patterned surface of PEEK microcarriers is 7806290 nm.After repeated steam sterilization by autoclaving for three times,topological PEEK microcarriers show nearly identical results compared with previous ones indicating strong tolerance to high temperature and pressure.This is a unique advantage for large-scale cell expansion and clinical applications.Moreover,PEEK microcarriers with special topography possess higher protein adsorption efficiency.In addition,the reutilization and biofunctionalization with repeated decellularization of topological PEEK microcarriers show highly beneficial for cell adhesion and proliferation.Therefore,our study is of great importance for new generation microcarriers with micro-and nano-scale surface feature for a broad application prospect in tissue engineering.

The challenge to improve the response of biomaterials to the physiological environment

New applications of biomaterials often require advanced structures containing synthetic and natural components that are tuned to provide properties unique to a specific application.We discuss how structural characteristics of biomaterials,especially hydrophilic ones,can be used in conjunction with non-ideal thermodynamics to develop advanced medical systems.We show a number of examples of biocompatible,intelligent biomaterials that can be used for organ replacement,biosensors,precise drug delivery over days or weeks,and regenerative medicine.

Two competitive nucleation mechanisms of calcium carbonate biomineralization in response to surface functionality in low calcium ion concentration solution

Four self-assembled monolayer surfaces terminated with–COOH,–OH,–NH_(2)and–CH_(3)functional groups are used to direct the biomineralization processes of calcium carbonate(CaCO_(3))in low Ca^(2+)concentration,and the mechanism of nucleation and initial crystallization within 12 h was further explored.On-COOH surface,nucleation occurs mainly via ion aggregation mechanism while prenucleation ions clusters may be also involved.On-OH and-NH_(2)surfaces,however,nucleation forms via calcium carbonate clusters,which aggregate in solution and then are adsorbed onto surfaces following with nucleation of amorphous calcium carbonate(ACC).Furthermore,strongly negative-charged-COOH surface facilitates the direct formation of calcites,and the-OH and-NH_(2)surfaces determine the formation of vaterites with preferred crystalline orientations.Neither ACC nor crystalline CaCO_(3)is observed on-CH_(3)surface.Our findings present a valuable model to understand the CaCO_(3)biomineralization pathway in natural system where functional groups composition plays a determining role during calcium carbonate crystallization.

Functional biomaterials for tendon/ligament repair and regeneration

With an increase in life expectancy and the popularity of highintensity exercise,the frequency of tendon and ligament injuries has also increased.Owing to the specificity of its tissue,the rapid restoration of injured tendons and ligaments is challenging for treatment.This review summarizes the latest progress in cells,biomaterials,active molecules and construction technology in treating tendon/ligament injuries.The characteristics of supports made of different materials and the development and application of different manufacturing methods are discussed.The development of natural polymers,synthetic polymers and composite materials has boosted the use of scaffolds.In addition,the development of electrospinning and hydrogel technology has diversified the production and treatment of materials.First,this article briefly introduces the structure,function and biological characteristics of tendons/ligaments.Then,it summarizes the advantages and disadvantages of different materials,such as natural polymer scaffolds,synthetic polymer scaffolds,composite scaffolds and extracellular matrix(ECM)-derived biological scaffolds,in the application of tendon/ligament regeneration.We then discuss the latest applications of electrospun fiber scaffolds and hydrogels in regeneration engineering.Finally,we discuss the current problems and future directions in the development of biomaterials for restoring damaged tendons and ligaments.

Evaluating the potential of an amelogenin-derived peptide in tertiary dentin formation

Several novel biomaterials have been developed for dental pulp capping by inducing tertiary dentin formation.The aim of this study was to evaluate the effect of QP5,an amelogenin-based peptide,on the mineralization of dental pulp cells(DPCs)in vitro and in vivo.The cell viability of human DPCs(hDPCs)after treatment with QP5 was determined using the Cell Counting Kit-8(CCK-8).Migration of hDPCs was assessed using scratch assays,and the pro-mineralization effect was determined using alkaline phosphatase(ALP)staining,alizarin red staining and the expression of mineralization-related genes and proteins.The results showed that QP5 had little effect on the cell viability,and significantly enhanced the migration capability of hDPCs.QP5 promoted the formation of mineralized nodules,and upregulated the activity of ALP,the expression of mRNA and proteins of mineralization-related genes.A pulp capping model in rats was generated to investigate the biological effect of QP5.The results of micro-computed tomography and haematoxylin and eosin staining indicated that the formation of tertiary dentin in QP5-capping groups was more prominent than that in the negative control group.These results indicated the potential of QP5 as a pulp therapy agent.

Syndecan-4 functionalization of tissue regeneration scaffolds improves interaction with endothelial progenitor cells

Key to most implanted cell free scaffolds for tissue regeneration is the ability to sequester and retain undifferentiated mesenchymal stem cells at the repair site.In this report,syndecan-4,a heparan sulfate containing proteoglycan,was investigated as a unique molecule for use in scaffold functionalization.An electrospun hybrid scaffold comprised of poly(glycerol)sebacate(PGS),silk fibroin and type I collagen(PFC)was used as a model scaffold to develop a procedure and test the hypothesis that functionalization would result in increased scaffold binding of endothelial progenitor cells(EPCs).For these studies both Syndecan-4 and stromal derived factor-1a(SDF-1a)were used in functionalization PFC.Syndecan-4 functionalized PFC bound 4.8 fold more SDF-1a compared to nonfunctionalized PFC.Binding was specific as determined by heparin displacement studies.After culture for 7 days,significantly,more EPCs were detected on PFC scaffolds having both syndecan-4 and SDF-1a compared to scaffolds of PFC with only syndecan-4,or PFC adsorbed with SDF-1a,or PFC alone.Taken together,this study demonstrates that EPCs can be bound to and significantly expanded on PFC material through syndecan-4 mediated growth factor binding.Syndecan-4 with a multiplicity of binding sites has the potential to functionalize and expand stem cells on a variety of scaffold materials for use in tissue regeneration.

Comparison of safety and efficiency of microendoscopic discectomy with automatic nerve retractor and with nerve hook

This study compares the safety and efficiency of two techniques in microendoscopic discectomy(MED)for lumbar disc herniation.The two techniques are MED with automatic nerve retractor and MED with nerve hook which had been widely used for many years.The former involves a newly developed MED device which contains three parts to protect nerve roots during operation.Four hundred and twenty-eight patients underwent MED treatments between October 2010 and September 2015 were recruited and randomized to either intraoperative utilization of automatic nerve retractor(n紏315,group A)or application of nerve hook during surgery(n=113,group B).Operation time and intraoperative bleeding volume were evaluated.Simultaneously,Visual Analogue Scales(VAS)and muscle strength grading were performed preoperatively,and 1,2,3 days,1,2 weeks,3 and 6 months postoperatively.No dramatic difference of pain intensity was observed between the two groups before surgery and 6 months after surgery(P>0.05).The operation time was shorter in group A(30.3061.89 min)than that in group B(59.4163.25 min).Group A(67.83613.14 ml)experienced a significant decrease in the amount of blood loss volume when compared with group B(100.04615.10 ml).There were remarkable differences of VAS score and muscle strength grading after postoperative 1,2,3 days,1,2 weeks and 3 months between both groups(P≤0.05).MED with automatic nerve retractor effectively shortened operation time,decreased the amount of bleeding,down-regulated the incidence of nerve traction injury.

A new method to standardize CBCT for quantitative evaluation of alveolar ridge preservation in the mandible:a case report and review of the literature

Cone-beam computerized tomography(CBCT)is an effective technique for assessment of changes to the alveolar ridge(AR).However,its accuracy and reliability could be improved by standardization of imaging positions to remain unchanged during measurements.In this study,an alveolar ridge preservation procedure was performed on a left third molar(38)socket by filling it with a radiotransparent synthetic bone graft,mineralized collagen(MC).Photographic,X-ray and CBCT images were captured before and 3,6 and 12 months after surgery.A new method was developed to standardize CBCT for quantitative evaluation.Obtained CBCT images showed good comparability.The post-extraction alveolar width and height were both over 95%of the original values,but some resorption of the lingual bone wall(>50%)and inter-crestal bone(>30%).It is concluded that an effective positional standardization method was developed for CBCT assessment of AR dimensional changes in the posterior mandible.The use of MC in combination with a collagen membrane improved dimensional preservation of the AR.

Immunomodulatory biomaterial-based wound dressings advance the healing of chronic wounds via regulating macrophage behavior

Successful wound healing is a process that has three overlying phases:inflammatory,proliferative and remodeling.Chronic wounds are characterized by a perpetuated inflammation that inhibits the proliferative and remodeling phases and impairs the wound healing.Macrophages are key modulators of the wound healing process.Initially,they are responsible for the wound cleaning and for the phagocytosis of pathogens and afterwards they lead to the resolution of the inflammatory response and they express growth factors important for angiogenesis and cytokines and growth factors needed for cell proliferation and deposition of extracellular matrix.The phenotype of the macrophage changes gradually throughout the healing process from the initial M1 pro-inflammatory phenotype characteristic of the acute response to the M2 pro-regenerative phenotype that allows an accurate tissue repair.In chronic wounds,M1 pro-inflammatory macrophages persist and impair tissue repair.As such,immunomodulatory biomaterials arise as promising solutions to accelerate the wound healing process.In this review,we discuss the importance of macrophages and their polarization throughout the different phases of wound healing;macrophage dysfunction in chronic wounds and the use of immunomodulatory biomaterials to overcome the critical problem of chronic wounds-the continued inflammatory phase that impairs healing.

Amyloid fragments and their toxicity on neural cells

The formation of amyloid fibrils from soluble proteins is a common form of self-assembly phenomenon that has fundamental connections with biological functions and human diseases.Lysozyme was converted from its soluble native state into highly organized amyloid fibrils.Ultrasonic treatment was used to break amyloid fibrils to fibrillar fragments–seeds.Atomic force microscopy and fluorescence microscopy was employed to characterize the morphology of the amyloid assemblies and neural cells–amyloid complexes.Our results demonstrate that prefibrillar intermediated and their mixture with proteins exhibit toxicity,although native proteins and fibrils appear to have no effect on number of cells.Our findings confirm that innocuous hen lysozyme can be engineered to produce both cytotoxic fibrillar fragments and non-toxic mature amyloid fibrils.Our work further strengthens the claim that amyloid conformation,and not the identity of the protein,is key to cellular toxicity and the underlying specific cell death mechanism.

Promoting proliferation and differentiation of BMSCs by green tea polyphenols functionalized porous calcium phosphate

In this article,we proposed a facile protocol to functionalize porous calcium phosphate ceramics(PCPC)using dietary tea polyphenols(TP).TP molecules was attracted and anchored by Ca2t ions from the surface of CPC.These TP molecules modulated the nucleation and crystallization of calcium phosphate nanorods assemblies on the surface of PCPC.Our results prove that these calcium phosphate nanorods assemblies accompanies functional groups of TP make PCPC/TP effectively promote proliferation and differentiation of bone mesenchymal stem cells(BMSCs).We inferred that these calcium phosphate nanorods assemblies might change the surface microenvironment of PCPC,which is critical to promote the proliferation and differentiation of BMSCs.Compared with naked PCPC,PCPC/TP obviously increased BMP2,ErK/MAPK and JNK/MAPK level and mineralization capacity of cells(ALP level).