Repair of Rat Segmental Defects with Mineralized Collagen Grafts Combined with or without Mesenchymal Stem Cells and BMP-2

The aim of the present study was to investigate and compare the bone formation capacity with three different grafts. Four millimeter segmental defects were created in adult rat tibias and were either left empty （control defects） or implanted with （1） nano-hydroxyapatite/collagen/PIA （nHAC/PIA） composite, （2） nHAC/ PIA composite added with bone marrow mesenchymal tem cells （ BMSCs ）, （ 3 ） nHAC/ PIA composite added with bone morphogenetic protein 2 （ BMP- 2）. Radiographs of the defects were taken weekly post-surgery. After 1 or 2 months, the rats were eathaaized. Histologic analyses were performed on the harvested tissue. nHAC/ PIA composite could enhance the repair of rat tibia segmental defects. Addition of BMSCs or BMP- 2 to nHAC/ PIA led to an increase in osteogenesis, nHAC/ PIA composite could be an Meal alternative bone-grafi material and it could also be used as an Meal carrier of BMSCs or BMP- 2.

High-strength mineralized collagen artificial bone

Mineralized collagen （MC） is a biomimetic material that mimics natural bone matrix in terms of both chemical composition and microstructure. The biomimetic MC possesses good biocompatibility and osteogenic activity, and is capable of guiding bone regeneration as being used for bone defect repair. However, mechanical strength of existing MC artificial bone is too low to provide effective support at human load-bearing sites, so it can only be used for the repair at non-load-bearing sites, such as bone defect filling, bone graft augmentation, and so on. In the present study, a high strength MC artificial bone material was developed by using collagen as the template for the biomimetic mineralization of the calcium phosphate, and then followed by a cold compression molding process with a certain pressure. The appearance and density of the dense MC were similar to those of natural cortical bone, and the phase composition was in conformity with that of animal＇s cortical bone demonstrated by XRD. Mechanical properties were tested and results showed that the compressive strength was comparable to human cortical bone, while the compressive modulus was as low as human cancellous bone. Such high strength was able to provide effective mechanical support for bone defect repair at human load-bearing sites, and the low compressive modulus can help avoid stress shielding in the application of bone regeneration. Both in vitro cell experiments and in v/vo implantation assay demonstrated good biocompatibility of the material, and in v/vo stability evaluation indicated that this high-strength MC artificial bone could provide long-term effective mechanical support at human load- bearing sites.

Clinical evaluations of mineralized collagen in the extraction sites preservation

The purpose of this study was to explore the different effects between biomimetic mineralized collagen(MC)and ordinary physically blended hydroxyapatite/collagen(HA/Col)composite in evaluating new bone formation and regenerated bone height in human extraction sockets.Thirty-four patients who cannot retain teeth caused by trauma or decay were randomly selected from Department of Stomatology of Dongzhimen Hospital from December 2013 to December 2014.The patients were randomly divided into two groups.After the operation of tooth extraction,17 patients were implanted with biomimetic MC(MC group),and other 17 patients were implanted with ordinary physically blended nHA/Col composite(nHA/Col group).X-ray positioning projection by auto-photographing was taken to test the distance between the lowest position and the neighboring CEJm-CEJd immediately,1 month and 3 months after the operation.The height of new bone formation of the MC group was significantly higher than the nHA/Col group.Biomimetic MC showed better clinical outcomes in the bone formation for extraction site preservation and would have broad application prospect in the field of oral and maxillofacial surgeries.

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.

Clinical evaluation following the use of mineralized collagen graft for bone defects in revision total hip arthroplasty

Revision total hip arthroplasty(THA)with massive bone loss has been a real challenge for orthopaedic surgeons.Here we describe an approach using mineralized collagen(MC)graft to reconstruct acetabulum and femur with massive bone defects.We identified 89 patients suffering acetabular or femoral bone defects after primary THA,who required revision THA for this study.During the surgery,MC was applied to reconstruct both the acetabular and femoral defects.Harris hip score was used to evaluate hip function while radiographs were taken to estimate bone formation in the defect regions.The average follow-up period was 33.662.4 months.None of the components needed re-revised.Mean Harris hip scores were 42.563.5 before operation,75.264.0 at 10th month and 95.063.6 at the final follow-up.There were no instances of deep infection,severe venous thrombosis or nerve palsy.The present study demonstrated that MC graft can serve as a promising option for revision THA with massive bone deficiency.Meanwhile,extended follow-up is needed to further prove its long-term performance.

Clinical observation of biomimetic mineralized collagen artificial bone putty for bone reconstruction of calcaneus fracture

This study investigated clinical outcomes of biomimetic mineralized collagen artificial bone putty for bone reconstruction in the treatment of calcaneus fracture.Sixty cases of calcaneal fractures surgically treated with open reduction and internal fixation in our hospital from June 2014–2015 were chosen and randomly divided into two groups,including 30 cases treated with biomimetic mineralized collagen artificial bone putty as treatment group,and 30 cases treated with autogenous ilia as control group.The average follow-up time was 17.263.0 months.The results showed that the surgery duration and postoperative drainage volume of treatment group were significantly lower than control group;there were no statistically significant differences in the fracture healing time,American Orthopaedic Foot and Ankle Society scores at 3 and 12 months after surgery,Bo¨hler’s angle,Gissane’s angle and height of calcaneus between the two groups.There were no significant differences in wound complication and reject reaction between the two groups,while significant difference in donor site complication.As a conclusion,the implantation of biomimetic mineralized collagen artificial bone putty in the open reduction of calcaneal fracture resulted in reliable effect and less complications,which is suitable for clinical applications in the treatment of bone defect in calcaneal fractures.

Efficacy of concentrated growth factors combined with mineralized collagen on quality of life and bone reconstruction of guided bone regeneration

To evaluate the clinical efficacy of concentrated growth factors(CGFs)combined with mineralized collagen(MC)in guided bone regeneration(GBR).A retrospective study involving 29 patients treated with GBR technique,which was performed either CGF and MC complexes or MC alone.Implants were inserted simultaneously and cone-beam computed tomography was taken immediately,at 3 and 6 months postoperation.Questionnaires were completed by all patients so as to evaluate the main symptoms and daily activities during the first week after surgery.The outcomes of the two groups were statistically compared.All implants healed uneventfully.Patients in both groups suffered from different levels of discomfort for the reason of swelling,pain and chewing impairment on 1-2 days.Meanwhile,swelling of the Trial group was weaker than the Control group.When compared with the Control group,pain levels in Trial group were more rapidly reduced and patients took fewer analgesics from Day 3.Furthermore,the reconstitution mean value of the graft was thicker at 3 and 6 months in Trial group.CGFs complex with MC were beneficial to relieve the clinical symptoms,promote the peri-implant bone regeneration and shorten the healing time.

A high-strength mineralized collagen bone scaffold for large-sized cranial bone defect repair in sheep

Large-sized cranial bone defect repair presents a great challenge in the clinic.The ideal cranioplasty materials to realize the functional and cosmetic recovery of the defect must have sufficient mechanical support,excellent biocompatibility,good osseointegration and biodegradability as well.In this study,a high-strength mineralized collagen(MC)bone scaffold was developed with biomimetic composition,microstructure and mechanical properties for the repair of sheep largesized cranial bone defects in comparison with two traditional cranioplasty materials,polymethyl methacrylate and titanium mesh.The compact MC scaffold showed no distinct pore structure and therefore possessed good mechanical properties.The strength and elastic modulus of the scaffold were much higher than those of natural cancellous bone and slightly lower than those of natural compact bone.In vitro cytocompatibility evaluation revealed that the human bone marrow mesenchymal stem cells(hBMSC)had good viability,attachment and proliferation on the compact MC scaffold indicating its excellent biocompatibility.An adult sheep cranial bone defect model was constructed to evaluate the performances of these cranioplasty materials in repairing the cranial bone defects.The results were investigated by gross observation,computed tomography scanning as well as histological assessments.The in vivo evaluations indicated that compact MC scaffold showed notable osteoconductivity and osseointegration with surrounding cranial bone tissues by promoting bone regeneration.Our results suggested that the compact MC scaffold has a promising potential for large-sized cranial bone defect repair.

Poly(methyl methacrylate) bone cement composited with mineralized collagen for osteoporotic vertebral compression fractures in extremely old patients

To examine the clinical effects of a new bone cement composed of poly(methyl methacrylate)(PMMA)and mineralized collagen(MC)compared with pure PMMA bone cement in treating osteoporotic vertebral compression fractures(OVCFs)in patients aged over 80.In all,32 cases using pure PMMA bone cement and 31 cases using MC-modified PMMA(MC-PMMA)bone cement for OVCFs between June 2014 and March 2016 were screened as PMMA group and MC-PMMA group,respectively,with an average age of over 80.The operation duration,intraoperative blood loss,hospital stay,oswestry disability index(ODI),visual analogue scale(VAS),anterior vertebral height(AVH),intermediate vertebral height(IVH)and posterior vertebral height(PVH)of injured vertebrae,vertebral computed tomography value,re-fracture rate of adjacent vertebrae,correction rate of spinal kyphotic angle and wedge-shaped vertebra angle and surgical complications were compared between the two groups.In the early post-operative period,the VAS,ODI,AVH and IVH in MC-PMMA group were comparable to those in the traditional PMMA group.Moreover,the MC-PMMA group showed better effects compared with the PMMA group 12months after surgery.Thus,this new bone cement has superior clinic effects in the long term.

Locking system strengthened by biomimetic mineralized collagen putty for the treatment of osteoporotic proximal humeral fractures

The current study is to observe the effect of the locking system strengthened by biomimetic mineralized collagen putty for the treatment of senile proximal humeral osteoporotic fractures.From January 2012 to December 2015,80 cases of senile patients with osteoporotic proximal humeral fractures were randomly divided into an observation group and a control group,each group with a total of 40 cases.The control group was simply treated with locking plate.The observation group was treated with locking plate in combination with biomimetic mineralized collagen putty.The therapeutic effect thereby was observed.The excellent and satisfactory rate was 90%in observation group and was 72.5%in control group.The difference between the two groups was statistically significant(χ^(2)=5.3312,P<0.05).The fracture healing time was 11.8263.62 weeks in observation group and 19.7865.46 weeks in control group.The shoulder joint function score was 89.6368.12 in observation group and 76.9268.18 in control group.There was significant difference between the two groups(t=7.1272;12.7834,P<0.05).The complication rate was 10%in the observation group and 32.5%in the control group(χ^(2)=7.3786,P<0.05).Locking system strengthened by biomimetic mineralized collagen putty has advantages such as accelerating healing of senile proximal humeral fracture,improving the therapeutic effect,reducing the complications.As one of the optimal internal fixation method,it provides a new option for better treatment of senile osteoporotic fracture.

Clinical observations of osteoporotic vertebral compression fractures by using mineralized collagen modified polymethylmethacrylate bone cement

To investigate the clinical outcomes of the treatment of osteoporotic vertebral compression fractures(OVCFs)by using mineralized collagen(MC)modified polymethylmethacrylate(PMMA)bone cement.52 cases(52 vertebras)who sustained OVCF treated with MC modified PMMA bone cement from July 2014 to December 2015 were reviewed retrospectively.All the cases(52 patients,52 vertebras)included 8 males and 44 females with an average age of 74.83(ranging from 57-to 90-years old).The visual analogue scale(VAS),vertebral body height,Cobb angle,CT values preand post-operation as well as incidence of complications were used to be observed.All the patients underwent the surgery were successfully followed-up with an average period of 13.54 months(ranging from 6 to 23 months).The patients can ambulate at the second day after the operation.The VAS scores 2 days after the operation and during the last follow-up were significantly decreased compared with that before the operation(P<0.05);the average vertebral height and local Cobb angle had significant recovery(P<0.05);the CT value of the treated vertebra significantly increased compared with that before the operation(P<0.05).MC with good osteogenic activity and degradation properties can effectively improve the mechanical properties and biocompatibility of the PMMA bone cement,thus obtain better clinical results.

Mineralized collagen artificial bone repair material products used for fusing the podarthral joints with internal fixation—a case report

In this study,we reported a case with collapse and subluxation of metatarsal-cuneiform joint,navicular-cuneiform joint with subluxed the right first metatarsophalangeal joint.The injured medial column was internally fixed with compression arthrodesis.The fusion site was firmed up with BonGoldVR Bone Sponge and Bone Putty.The prognosis of fused navicular-cuneiform joint and metatarsal-cuneiform joint were examined by X-ray shortly after surgical operation and followed up 2,4,6,9 and 13 weeks after the surgical operation.Themedial column was perfectly fused by compression arthrodesis.These results justified and favored the application of mineralized collagen as an excellent alternative to autograft in fusing the podarthral joints with internal fixation.

Enhancement of BMP-2 and VEGF carried by mineralized collagen for mandibular bone regeneration

Repairing damage in the craniofacial skeleton is challenging.Craniofacial bones require intramembranous ossification to generate tissue-engineered bone grafts via angiogenesis and osteogenesis.Here,we designed a mineralized collagen delivery system for BMP-2 and vascular endothelial growth factor(VEGF)for implantation into animal models of mandibular defects.BMP-2/VEGF were mixed with mineralized collagen which was implanted into the rabbit mandibular.Animals were divided into(i)controls with no growth factors;(ii)BMP-2 alone;or(iii)BMP-2 and VEGF combined.CT and hisomputed tomography and histological staining were performed to assess bone repair.New bone formation was higher in BMP-2 and BMP-2-VEGF groups in which angiogenesis and osteogenesis were enhanced.This highlights the use of mineralized collagen with BMP-2/VEGF as an effective alternative for bone regeneration.

Mineralized collagen-modified PMMA cement enhances bone integration and reduces fibrous encapsulation in the treatment of lumbar degenerative disc disease

As a minimally invasive surgery,percutaneous cement discoplasty(PCD)is now contemplated to treat lumbar disc degeneration disease in elder population.Here,we investigated whether the osteogenic mineralized collagen(MC)modified polymethylmethacrylate(PMMA)cement could be a suitable material in PCD surgery.Injectability,hydrophilicity and mechanical properties of the MC-modified PMMA(PMMA-MC)was characterized.The introduction of MC did not change the application and setting time of PMMA and was easy to be handled in minimally invasive operation.Hydrophilicity of PMMA-MC was greatly improved and its elastic modulus was tailored to complement mechanical performance of bone under dynamic stress.Then,PCD surgery in a goat model with induced disc degeneration was performed with implantation of PMMA-MC or PMMA.Three months after implantation,micro-computed tomography analysis revealed a 36.4%higher circumferential contact index between PMMA-MC and bone,as compared to PMMA alone.Histological staining confirmed that the surface of PMMA-MC was in direct contact with new bone,while the PMMA was covered by fibrous tissue.The observed gathering of macrophages around the implant was suspected to be the cause of fibrous encapsulation.Therefore,the interactions of PMMA and PMMA-MC with macrophages were investigated in vitro.We discovered that the addition of MC could hinder the proliferation and fusion of the macrophages.Moreover,expressions of fibroblaststimulating growth factors,insulin-like growth factor,basic fibroblast growth factor and tumor necrosis factor-b were significantly down-regulated in the macrophages cocultured with PMMA-MC.Together,the promoted osteointegration and reduced fibrous tissue formation observed with PMMA-MC material makes it a promising candidate for PCD surgery.

Efficacy of a mineralized collagen bone-grafting material for peri-implant bone defect reconstruction in mini pigs

The mechanism of the mineralization process induced by natural mineralized collagen(MC)has been investigated for decades.The purpose of this study was to investigate the efficacy of selfassembled MC for peri-implant bone defect reconstruction in a mini pig.A standardized peri-implant bone defect model was created using 14 mini pig mandibles.Two materials were evaluated,i.e.a mixture of hydroxyapatite and collagen(Type A,TA),and self-assembled MC(Type B,TB).Bio-Oss(BO)and untreated(blank control,BC)groups were used as controls.After 3-and 6-month healing periods,the mini pigs were sacrificed for histomorphometric and microcomputed tomography analysis.After 3 months of healing,the average alveolar ridge height was 3.2761.57mm for group TA,3.28±2.02mm for group TB and 3.37±1.09mm for group BO,while group BC showed the lowest height of 2.68±0.47mm.After 6 months of healing,the average alveolar ridge height was 2.64±1.13mm for group TA,4.31±1.80mm for group TB and 3.8761.38mm for group BO,while group BC showed the lowest height of 2.48±1.80mm.The experimental groups and control group showed similar bone volume density,bone complexity and histological reaction.The self-assembled MC(Type B)stimulated new bone formation in the reconstruction of deficient alveolar ridges around the dental implant;it also displayed excellent clinical operability compared with bone grafts without collagen.

Development of an antimicrobial peptide-loaded mineralized collagen bone scaffold for infective bone defect repair

The repair of infective bone defects is a great challenge in clinical work.It is of vital importance to develop a kind of bone scaffold with good osteogenic properties and long-term antibacterial activity for local anti-infection and bone regeneration.A porous mineralized collagen(MC)scaffold containing poly(D,L-lactide-co-glycolic acid)(PLGA)microspheres loaded with two antibacterial synthetic peptides,Pac-525 or KSL-W was developed and characterized via scanning electron microscopy(SEM),porosity measurement,swelling and mechanical tests.The results showed that the MC scaffold embedded with smooth and compact PLGA microspheres had a positive effect on cell growth and also had antibacterial properties.Through toxicity analysis,cell morphology and proliferation analysis and alkaline phosphatase evaluation,the antibacterial scaffolds showed excellent biocompatibility and osteogenic activity.The antibacterial property evaluated with Staphylococcus aureus and Escherichia coli suggested that the sustained release of Pac-525 or KSL-W from the scaffolds could inhibit the bacterial growth aforementioned in the long term.Our results suggest that the antimicrobial peptides-loaded MC bone scaffold has good antibacterial and osteogenic activities,thus providing a great promise for the treatment of infective bone defects.

Clinical observation of mineralized collagen bone grafting after curettage of benign bone tumors

Curettage of benign bone tumor is a common cause for bone defect.For such bone defect repair,autogenous bone,allogeneic bone and traditional artificial bone graft substitutes have many disadvantages.In recent years,a biomimetic mineralized collagen(MC)with similar composition and microstructures to the natural bone matrix was developed and used for treating various bone defects.In this work,a retrospective study analyzed clinical outcomes of patients treated with curettage of benign bone tumors and bone grafting with MC,in comparison to another group treated with the same surgical method and autogenous bone.Lane-Sandhu X-ray score of the autogenous bone group was superior to the MC group at 1 month after the operation,but the two groups had no statistical difference at 6 and 12 months.The MC group was better in Musculoskeletal Tumor Society scoring at 1 and 6 months after the operation,and the two groups had no statistical difference at 12 month.Therefore,the MC performed not as good as autogenous bone in early stage of bone healing but achieved comparable outcomes in long-term follow-ups.Moreover,the MC has advantages in function recovery and avoided potential complications induced by harvesting autogenous bone.

Mineralized collagen scaffolds fabricated with amniotic membrane matrix increase osteogenesis under inflammatory conditions

Defects in craniofacial bones occur congenitally,after high-energy impacts,and during the course of treatment for stroke and cancer.These injuries are difficult to heal due to the overwhelming size of the injury area and the inflammatory environment surrounding the injury.Significant inflammatory response after injury may greatly inhibit regenerative healing.We have developed mineralized collagen scaffolds that can induce osteogenic differentiation and matrix biosynthesis in the absence of osteogenic media or supplemental proteins.The amniotic membrane is derived from placentas and has been recently investigated as an extracellular matrix to prevent chronic inflammation.Herein,we hypothesized that a mineralized collagen-amnion composite scaffold could increase osteogenic activity in the presence of inflammatory cytokines.We report mechanical properties of a mineralized collagen-amnion scaffold and investigated osteogenic differentiation and mineral deposition of porcine adipose-derived stem cells within these scaffolds as a function of inflammatory challenge.Incorporation of amniotic membrane matrix promotes osteogenesis similarly to un-modified mineralized collagen scaffolds,and increases in mineralized collagen-amnion scaffolds under inflammatory challenge.Together,these findings suggest that a mineralized collagen-amnion scaffold may provide a beneficial environment to aid craniomaxillofacial bone repair,especially in the course of defects presenting significant inflammatory complications.

The observed difference of macrophage phenotype on different surface roughness of mineralized collagen

Biomaterials regulate macrophages and promote regeneration function,which is a new hot pot in tissue engineering and regenerative medicine.The research based on macrophage materials biology has appeared happy future,but related research on regulating macrophages and promoting tissue regeneration is still in its infancy.The surface roughness of biomaterials is one of the important factors affecting macrophage behavior.Previous study also found that the surface roughness of many biomaterials regulating macrophage polarization,but not including mineralized collagen(MC).In this study,we designed and fabricated MC with different roughness and investigated the influence of MC with different roughness on macrophages.In the study,we found that on the rough surface of MC,macrophages exhibited M1 phenotype-amoeboid morphology and high-level secretory of inflammatory factor(tumor necrosis factor-a and interleukin-6),while smoother surface exhibited M2 phenotype.These data will be beneficial to understand the mechanism deeply and enrich biomaterials tissue regeneration theory,provide a new train of thought biomaterials inducing tissue regeneration and repair and guide the optimum design of new biomaterials,development and reasonable applications.

Histopathological and imageological studies on clinical outcomes of mineralized collagen reconstruction rod for femoral head necrosis with one case report

In this article,the biodegradation process and bone formation of a mineralized collagen reconstruction rod embedding in necrosis of human femoral head were investigated by imageological and histological methods.Computed radiography(CR)computerized tomography(CT),common pathological section and hard tissue section analysis were used to evaluated the dynamics of imageological and histopathological changes of femoral head,interface between the host bone and implant and the bone reconstruction process.The results showed that the density of rods increased closed to that of host bones after 1 year implanting,and the interface between them turns to blurring.Hard tissue grinding sections analysis showed osteocytes appearing in sparse bone trabecular and bone pit region,as well as a few vessels in the degraded dye powder matrix were noticed,indicating the new bone forming between the implants and host bones.Regular decalcified sections analysis showed scattered osteoclasts,multinucleated giant cells and fibrosis components existing in the degraded rod and the host bone trabecular.Degraded debris was endocytosed by giant cells,and vascular network formed around the boundaries of the implanted rod.The good osteointegration has been expressed by the interface between the implanted rod and the host bone becoming blurred.Histological results indicated that the implanted rod degradation process and new bones regeneration simultaneously occurred around the boundaries of embedding rod.New bone and host bone were hinged and co-existed.