Stem Cell Fate and Immunomodulation Promote Bone Regeneration via Composite Bio-Oss®/AviteneTM Biomaterial

Bone defects in maxillofacial regions lead to noticeable deformity and dysfunctions. Therefore, the use of biomaterials/scaffolds for maxillofacial bone regrowth has been attracting great interest from many surgical specialties and experts. Many approaches have been devised in order to create an optimal bone scaffold capable of achieving desirable degrees of bone integration and osteogenesis. Osteogenesis represents a complex physiological process involving multiple cooperating systems. A tight relationship between the immune and skeletal systems has lately been established using the concept of “osteoimmunology,” since various molecules, particularly those regulating immunological and inflammatory processes, are shared. Inflammatory mediators are now being implicated in bone remodeling, according to new scientific data. In this study, a profiler PCR array was employed to evaluate the expression of cytokines and chemokines in human adipose derived-mesenchymal stem cells (hASCs) cultured on porous hydroxylapatite (HA)/Collagen derived Bio-Oss® /Avitene scaffolds, up to day 21. In hASCs grown on the Bio-Oss® /Avitene biomaterial, 12 differentially expressed genes (DEGs) were found to be up-regulated, together with 12 DEG downregulated. Chemokine CCL2, which affects bone metabolism, tested down-regulated. Interestingly, the Bio-Oss® /Avitene induced the down-regulation of pro-inflammatory interleukin IL-6. In conclusion, our investigation carried out on the Bio-Oss® /Avitene scaffold indicates that it could be successfully employed in maxillofacial surgery. Indeed, this composite material has the advantage of being customized on the basis of the individual patients favoring a novel personalized medicine approach

Genetics and Epigenetics of Bone Remodeling and Metabolic Bone Diseases

Bone metabolism consists of a balance between bone formation and bone resorption, which is mediated by osteoblast and osteoclast activity, respectively. In order to ensure bone plasticity, the bone remodeling process needs to function properly. Mesenchymal stem cells differentiate into the osteoblast lineage by activating different signaling pathways, including transforming growth factor β (TGF-β)/bone morphogenic protein (BMP) and the Wingless/Int-1 (Wnt)/β-catenin pathways. Recent data indicate that bone remodeling processes are also epigenetically regulated by DNA methylation, histone post-translational modifications, and non-coding RNA expressions, such as micro-RNAs, long non-coding RNAs, and circular RNAs. Mutations and dysfunctions in pathways regulating the osteoblast differentiation might influence the bone remodeling process, ultimately leading to a large variety of metabolic bone diseases. In this review, we aim to summarize and describe the genetics and epigenetics of the bone remodeling process. Moreover, the current findings behind the genetics of metabolic bone diseases are also reporte

Acute Prosthetic Joint Infections with Poor Outcome Caused by Staphylococcus Aureus Strains Producing the Panton-Valentine Leukocidin

The aim of this study was to investigate whether the presence of Staphylococcus aureus (SA) producing the Panton-Valentine leukocidin (PVL) affects the outcome of Prosthetic Joint Infection (PJI). Patients with acute and chronic PJI sustained by SA were prospectively enrolled at the orthopedic unit of "Casa di Cura Santa Maria Maddalena", from January 2019 to October 2021. PJI diagnosis was reached according to the diagnostic criteria of the International Consensus Meeting on PJI of Philadelphia. Synovial fluid obtained via joint aspirations was collected in order to isolate SA. The detection of PVL was performed via real-time quantitative PCR (RT-qPCR). The outcome assessment was performed using the criteria of the Delphi-based International Multidisciplinary Consensus. Twelve cases of PJI caused by SA were included. Nine (75%) cases were acute PJI treated using debridement, antibiotic and implant retention (DAIR); the remaining three (25%) were chronic PJI treated using two-stage (n = 2) and one-stage revision (n = 1), respectively. The SA strains that tested positive for PVL genes were 5/12 (41.6%,). Treatment failure was documented in three cases of acute PJI treated using DAIR, all supported by SA-PVL strains (p < 0.045). The remaining two cases were chronic PJI treated with a revision arthroplasty (one and two stage, respectively), with a 100% eradication rate in a medium follow-up of 24 months. Although a small case series, our study showed a 100% failure rate in acute PJI, probably caused by SA PVL-producing strains treated conservatively (p < 0.04). In this setting, toxin research should guide radical surgical treatment and targeted antibiotic therapy

Hydroxylapatite-collagen hybrid scaffold induces human adipose-derived mesenchymal stem cells to osteogenic differentiation in vitro and bone regrowth in patients

Tissue engineering-based bone graft is an emerging viable treatment modality to repair and regenerate tissues damaged as a result of diseases or injuries. The structure and composition of scaffolds should modulate the classical osteogenic pathways in human stem cells. The osteoinductivity properties of the hydroxylapatite-collagen hybrid scaffold named Coll/Pro Osteon 200 were investigated in an in vitro model of human adipose mesenchymal stem cells (hASCs), whereas the clinical evaluation was carried out in maxillofacial patients. Differentially expressed genes (DEGs) induced by the scaffold were analyzed using the Osteogenesis RT2 PCR Array. The osteoinductivity potential of the scaffold was also investigated by studying the alkaline phosphatase (ALP) activity, matrix mineralization, osteocalcin (OCN), and CLEC3B expression protein. Fifty patients who underwent zygomatic augmentation and bimaxillary osteotomy were evaluated clinically, radiologically, and histologically during a 3-year follow-up. Among DEGs, osteogenesis-related genes, including BMP1/2, ALP, BGLAP, SP7, RUNX2, SPP1, and EGFR, which play important roles in osteogenesis, were found to be upregulated. The genes to cartilage condensation SOX9, BMPR1B, and osteoclast cells TNFSF11 were detected upregulated at every time point of the investigation. This scaffold has a high osteoinductivity revealed by the matrix mineralization, ALP activity, OCN, and CLEC3B expression proteins. Clinical evaluation evidences that the biomaterial promotes bone regrowth. Histological results of biopsy specimens from patients showed prominent ossification. Experimental data using the Coll/Pro Osteon 200 indicate that clinical evaluation of bone regrowth in patients, after scaffold implantation, was supported by DEGs implicated in skeletal development as shown in "in vitro" experiments with hASCs

Hydroxylapatite-collagen hybrid scaffold induces human adipose-derived mesenchymal stem cells to osteogenic differentiation in vitro and bone regrowth in patients

Tissue engineering-based bone graft is an emerging viable treatment modality to repair and regenerate tissues damaged as a result of diseases or injuries. The structure and composition of scaffolds should modulate the classical osteogenic pathways in human stem cells. The osteoinductivity properties of the hydroxylapatite-collagen hybrid scaffold named Coll/Pro Osteon 200 were investigated in an in vitro model of human adipose mesenchymal stem cells (hASCs), whereas the clinical evaluation was carried out in maxillofacial patients. Differentially expressed genes (DEGs) induced by the scaffold were analyzed using the Osteogenesis RT2 PCR Array. The osteoinductivity potential of the scaffold was also investigated by studying the alkaline phosphatase (ALP) activity, matrix mineralization, osteocalcin (OCN), and CLEC3B expression protein. Fifty patients who underwent zygomatic augmentation and bimaxillary osteotomy were evaluated clinically, radiologically, and histologically during a 3-year follow-up. Among DEGs, osteogenesis-related genes, including BMP1/2, ALP, BGLAP, SP7, RUNX2, SPP1, and EGFR, which play important roles in osteogenesis, were found to be upregulated. The genes to cartilage condensation SOX9, BMPR1B, and osteoclast cells TNFSF11 were detected upregulated at every time point of the investigation. This scaffold has a high osteoinductivity revealed by the matrix mineralization, ALP activity, OCN, and CLEC3B expression proteins. Clinical evaluation evidences that the biomaterial promotes bone regrowth. Histological results of biopsy specimens from patients showed prominent ossification. Experimental data using the Coll/Pro Osteon 200 indicate that clinical evaluation of bone regrowth in patients, after scaffold implantation, was supported by DEGs implicated in skeletal development as shown in "in vitro" experiments with hASCs

Enhancement of the Biological and Mechanical Performances of Sintered Hydroxyapatite by Multiple Ions Doping

In the present work, hydroxyapatite (HA) nanoparticles doped with Mg2+, Sr2+, and Zn2+ ions are developed by wet neutralization method and then sintered at 1,250°C to obtain bulk consolidated materials. Physicochemical and microstructural analyses show that the presence of doping ions in the HA structure induced the formation of βTCP as secondary phase, during the sintering process, and we found that this effect is depending on the stability of the various doping ions in the hydroxyapatite lattice itself. We also found that the formation of βTCP as secondary phase, in turn, confines the grain growth of HA induced by the high-temperature sintering process, thus leading to a strong increase of the flexural strength of the bulk materials, according to Hall-Petch-like law. Furthermore, we found that the doping ions enter also in the structure of the βTCP phase; besides the grain growth confinement, also the solubility and ion release ability of the final materials were enhanced. In addition to ameliorate the mechanical performance, the described phenomena also activate multiple biofunctionalities: (i) ability to upregulate various genes involved in the osteogenesis, as obtained by human adipose stem cells culture and evaluated by array technology; (ii) enhanced resistance to the adhesion and proliferation of Gram+ and Gram– bacterial strains. Hence, our results open a perspective for the use of sintered multiple ion-doped HA to develop ceramic biodevices, such as plates, screws, or other osteosynthesis media, with enhanced strength, osteointegrability, and the ability to prevent post-surgical infections

Prevalence of IgG antibodies against Malawi polyomavirus in patients with autoimmune diseases and lymphoproliferative disorders subjected to bone marrow transplantation

IntroductionHuman polyomaviruses (HPyVs) cause persistent/latent infections in a large fraction of the population. HPyV infections may cause severe diseases in immunocompromised patients. Malawi polyomavirus (MWPyV) is the 10th discovered human polyomavirus (HPyV 10). MWPyV was found in stool samples of healthy children. So far, the few investigations carried out on HPyV 10 did not find an association with human disease.MethodsIn this study, to verify the putative association between MWPyV and human diseases, MWPyV seroprevalence was investigated in patients affected by i) lymphoproliferative disorders (LPDs) and ii) immune system disorders, i.e., autoimmune diseases (ADs), and in iii) healthy subjects. An indirect ELISA, employing virus-like particles (VLPs) to detect serum IgG antibodies against MWPyV/HPyV 10, was carried out. The study also revealed the prevalence of another polyomavirus, Merkel cell polyomavirus (MCPyV).ResultsSera from patients with distinct autoimmune diseases (n = 44; mean age 20 years) had a prevalence of MWPyV antibodies of 68%, while in patients with lymphoproliferative disorders (n = 15; mean age 14 years), subjected to bone marrow transplantation, the prevalence was 47%. In healthy subjects (n = 66; mean age 13 years), the prevalence of MWPyV antibodies was 67%. Our immunological investigation indicates that MWPyV/HPyV 10 seroconversion occurs early in life and MWPyV/HPyV 10 appears to be another polyomavirus ubiquitous in the human population. A significantly lower MWPyV antibody reactivity together with a lower immunological profile was detected in the sera of LPD patients compared with HS2 (*p < 0.05) (Fisher’s exact test). LPD and AD patients have a similar MCPyV seroprevalence compared with healthy subjects.DiscussionMWPyV seroprevalence indicates that this HPyV is not associated with lymphoproliferative and autoimmune diseases. However, the ability to produce high levels of antibodies against MWPyV appears to be impaired in patients with lymphoproliferative disorders. Immunological investigations indicate that MWPyV seroconversion occurs early in life. MCPyV appears to be a ubiquitous polyomavirus, like other HPyVs, in the human population

In vitro mesenchymal stem cell osteogenic differentiation and immunomodulation, and bone regrowth in patients, are induced by innovative biomaterials

INTRODUCTION. Bone is a rigid and highly dynamic structure that protects several organs of the body. Although bone fracture repair usually restores the injured skeletal organ to its pre-injury state, approximately 10% of fractures do not heal properly. Indeed, the bone regeneration process could fail in extensive bone resections or atrophic non-union. Moreover, face rehabilitation, both functional and aesthetic, has grown in importance in maxillofacial surgery. In tissue engineering, stem cells and new osteoconductive and osteoinductive biomaterials are employed to improve bone repair. Human mesenchymal stem cells derived from adipose tissue (hASCs) and bone marrow (hBMSCs) are probably the most common stem cells used in clinical practice. In vitro, osteogenic differentiation cocktails typically contain at least 10 nM of dexamethasone (dex). Recent studies provide evidence for an off-target adipocytic differentiation in standard osteogenic cultures of hBMSCs induced by dex. Dex induces osteogenesis by inhibiting SRY-Box Transcription Factor 9 (SOX9) gene expression and not by up-regulating the expression of RUNX Family Transcription Factor 2 (RUNX2). Moreover, dex also stimulates adipogenesis by inducing the expression of peroxisome proliferator-activated receptor gamma (PPARG), the adipogenic transcription factor. It is not clear which factor mediates SOX9 downregulation: PPARG is one promising candidate. AIMS. At first, the present project aims to evaluate the cytocompatibility and osteoinductivity proprieties of different scaffolds, which can improve bone regeneration, using hASCs as in vitro cellular model. The characteristics of two Hydroxylapatite (HA)/Collagen composite scaffolds employed in maxillofacial surgery, i.e. Pro Osteon 200/Avitene and Bio-Oss/Avitene, have been evaluated up to 40 days. Patients operated for maxillomandibular malocclusion and/or asymmetry, or for aesthetic reasons, who underwent malar augmentation with porous HA/Collagen prostheses, were evaluated for the new bone formation. Moreover, because inflammation is an important factor that should be considered to develop successful biomaterial-based therapeutics, the immune response of hASCs grown on both Pro Osteon 200/Avitene and Bio-Oss/Avitene scaffolds has been evaluated after 21 days. In the second part, it has been evaluated an innovative HA-derived biomaterial obtained through a new procedure of “biomorphic” transformation, which can directly transform wood pieces into large HA scaffolds, preserving the original multiscale structure through a heterogeneous reaction under supercritical conditions, directly in the 3D state, without adopting any sintering process. In the last part of this project, experiments focused on the mechanisms of dex-induced osteogenesis of hBMSCs have been conducted using T0070907 PPARG inhibitor. RESULTS AND CONCLUSION. My experimental data showed that: i) Pro Osteon 200/Avitene and Bio-Oss/Avitene are suitable materials to be used in maxillofacial surgery, ii) the biomorphic HA has the ability to modulate various osteogenic genes and genes related to osteoclast differentiation in hASCs, indicating that the use of scaffold associating biomimetic composition and nanostructure, enabling higher surface activity, is a promising route towards the development of new bio-devices with superior performance in the regeneration of bone tissue and iii) dex induces hBMSCs osteogenic differentiation enhancing RUNX2/SOX9 ratio. Dex induces PPARG gene expression and inhibits SOX9 expression, as expected. Moreover, the PPARG inhibitor T0070907 seems to inhibit both transactivation and transrepression activities of PPARG. Further investigations are needed to understand SOX9 down-regulation in the presence of dex and T0070907. Indeed, new analyses with siRNAs, which effectively knock down PPARG gene expression, together with PPARG and SOX9 protein expression experiments, may elucidate this issue.INTRODUZIONE. L'osso è una struttura rigida e dinamica che protegge diversi organi del corpo. Sebbene la riparazione delle fratture ossee di solito riporti l’osso danneggiato al suo stato pre-lesione, circa il 10% delle fratture non guarisce correttamente. Infatti, il processo di rigenerazione potrebbe fallire nel caso di resezioni ossee estese o di pseudoartrosi. Inoltre, la riabilitazione facciale, sia funzionale che estetica, ha acquisito nel tempo una maggiore importanza nella chirurgia maxillo-facciale. Le cellule staminali di diversa origine tissutale e distinti nuovi biomateriali osteoinduttivi sono impiegati per migliorare la riparazione ossea. Nella pratica clinica, le cellule staminali mesenchimali umane derivate da tessuto adiposo (hASCs) e da midollo osseo (hBMSCs) sono probabilmente quelle più utilizzate. In vitro, i cocktails impiegati per indurre il differenziamento osteogenico contengono almeno 10 nM di desametasone (dex). Il dex, però, induce anche un differenziamento adipocitario off-target nelle hBMSCs indotte al differenziamento osteogenico. Dex induce l'osteogenesi inibendo l'espressione di SRY-Box Transcription Factor 9 (SOX9) e non stimolando l'espressione di RUNX Family Transcription Factor 2 (RUNX2). Inoltre, dex stimola anche l'adipogenesi inducendo l'espressione di peroxisome proliferator-activated receptor gamma (PPARG). Tuttavia, ulteriori studi sono necessari per identificare quali mediatori portano alla down-regolazione di SOX9: PPARG è un candidato promettente. OBIETTIVI. Inizialmente, sono state valutate le proprietà di citocompatibilità e osteoinduttività di due biomateriali compositi, costituiti da idrossiapatite (HA)/collagene (Avitene), impiegati in chirurgia maxillo-facciale, ovvero Pro Osteon 200/Avitene e Bio-Oss/Avitene, utilizzando le hASCs come modello cellulare in vitro. Le loro caratteristiche sono state valutate fino a 40 giorni. Pazienti sottoposti ad aumento zigomatico utilizzando le suddette protesi, per malocclusione maxillo-mandibolare e/o asimmetria, sono stati valutati per la neoformazione ossea. Poiché l'infiammazione è un fattore importante da considerare per lo sviluppo di terapie efficaci a base di biomateriali, la risposta immunitaria delle hASCs cresciute su entrambi i biomateriali in esame è stata valutata dopo 21 giorni. In una seconda fase, è stato valutato un innovativo biomateriale HA-derivato ottenuto attraverso un nuovo processo di trasformazione “biomorfica”, in grado di trasformare pezzi di legno direttamente in biomateriali, preservando la struttura multi-scala originaria, senza adottare alcun processo di sinterizzazione. Nell'ultima parte di questo progetto, sono stati condotti esperimenti incentrati sui meccanismi dell'osteogenesi indotta da dex in hBMSCs utilizzando un inibitore di PPARG (T0070907). RISULTATI E CONCLUSIONE. I risultati ottenuti hanno dimostrato che: i) i biomateriali Pro Osteon 200/Avitene e Bio-Oss/Avitene sono idonei per l'uso in chirurgia maxillo-facciale, ii) il biomateriale biomorfico HA-derivato ha la capacità di modulare vari geni osteogenici e geni correlati al differenziamento degli osteoclasti nelle hASCs, indicando che l'uso di biomateriali con queste caratteristiche chimico-fisiche aprono a nuove prospettive di sviluppo di nuovi dispositivi con prestazioni superiori e iii) dex induce il differenziamento osteogenico delle hBMSCs migliorando il rapporto RUNX2/SOX9. Dex, inoltre, induce l'espressione del gene PPARG ed inibisce l'espressione di SOX9, come previsto. L'inibitore di PPARG, T0070907, sembra influenzare negativamente sia la sua attività di trans-attivazione che di trans-repressione. Sono necessarie ulteriori indagini per capire il motivo della down-regolazione di SOX9 in presenza di dex e T0070907. Ulteriori indagini potrebbero essere eseguite utilizzando un siRNAs per bloccare efficacemente l'espressione genica di PPARG, analizzando anche l'espressione di PPARG e SOX9 a livello proteico

Human Mesenchymal Stem Cells and Innovative Scaffolds for Bone Tissue Engineering Applications

: Stem cell-based therapy is a significant topic in regenerative medicine, with a predominant role being played by human mesenchymal stem cells (hMSCs). The hMSCs have been shown to be suitable in regenerative medicine for the treatment of bone tissue. In the last few years, the average lifespan of our population has gradually increased. The need of biocompatible materials, which exhibit high performances, such as efficiency in bone regeneration, has been highlighted by aging. Current studies emphasize the benefit of using biomimetic biomaterials, also known as scaffolds, for bone grafts to speed up bone repair at the fracture site. For the healing of injured bone and bone regeneration, regenerative medicine techniques utilizing a combination of these biomaterials, together with cells and bioactive substances, have drawn a great interest. Cell therapy, based on the use of hMSCs, alongside materials for the healing of damaged bone, has obtained promising results. In this work, several aspects of cell biology, tissue engineering, and biomaterials applied to bone healing/regrowth will be considered. In addition, the role of hMSCs in these fields and recent progress in clinical applications are discussed. Impact Statement The restoration of large bone defects is both a challenging clinical issue and a socioeconomic problem on a global scale. Different therapeutic approaches have been proposed for human mesenchymal stem cells (hMSCs), considering their paracrine effect and potential differentiation into osteoblasts. However, different limitations are still to be overcome in using hMSCs as a therapeutic opportunity in bone fracture repair, including hMSC administration methods. To identify a suitable hMSC delivery system, new strategies have been proposed using innovative biomaterials. This review provides an update of the literature on hMSC/scaffold clinical applications for the management of bone fractures

Pro osteon/collagen hydroxylapatite hybrid scaffold is able to induce human mesechymal stem cells (hMSCs) to osteogenic differentiation

Aim. Innovative scaffolds are of paramount importance for bone grafting and re-growth. Distinct enhancements of scaffold properties may optimize the product performance for different applications in the fields of maxillofacial and odontoiatric sciences/clinics. The most common scaffold improvements were obtained for their biocompatibility, mechanical properties in osteo-conductive and osteo-inductive properties and healing rate. In this study an innovative hydroxylapatite hybrid scaffold composed of granular hydroxylapatite (Pro Osteon ® 200, Interpore Cross Irvine, CA, USA) and collagen Hemostat (Bard Warwick, Rhode Island, USA) (Coll/HA) was investigated using human bone marrow-derived mesenchymal stem cells (hMSCs) of adult donors (1-3). Materials and Methods. In order to evaluate (i) biocompatibility, (ii) osteoconductivity and (iii) osteoinductivity hMSC cultures were grown on the innovative scaffold. The cellular morphology, cytoskeleton organization, and cell viability were studied by immunohistochemistry (IHC), and AlamarBlue metabolic assay respectively. Osteocalcin and osteopontin expression proteins were detected by IHC. The temporal osteocalcin expression protein in hMSCs grown on the biomaterial and in osteogenic condition (OC), and the control (TCPS), were quantified by Human Osteocalcin Instant E.L.I.S.A assays. Expression of osteogenic genes were evaluated by quantitative PCR (Q-PCR) array technologies; the Human Osteogenesis RT² Profiler PCR Array (Qiagen) was used to analyze the expression of 84 genes related to osteogenic differentiation at day 21. Results. Cell morphology of hMSC–eGFP cells was indistinguishable from that of parental hMSC. Indeed, hMSC-eGFP grown on the scaffold showed a normal morphology. Metabolic activity was increased during the 21 days of experiments (P<0.05). The cytoskeleton architecture seemed to be well organized, whereas its integrity remains uninfluenced by the scaffold during the time course. The biomaterial induced the matrix mineralization in hMSCs at day 14. Osteogenic proteins, such as osteocalcin and osteopontin were detected at day 21.The biomaterial induced the up-regulation of osteocalcin protein expression levels, quantified in E.L.I.S.A assay at day 21, compared to control (TCPS) and at day 14. Gene expression analyzed in hMSCs allowed us to detect the upregulation of mRNAs of 16 genes, belonging to the osteogenic differentiation pathway. Specific genes were for (i) the ossification process: BMP2/3, COL2A1, MMP9, NOG, SPP1, TNFSF11, TGFB3, (ii) osteoblast differentiation were: GLI1, SMAD3, SP7, (iii) whereas for the extracellular matrix (ECM) and cell adhesion molecules were: MMP10, ICAM1, ITGAM, CD36. In addition, the growth factor CSF3 was also up-regulated compared to the control, ad day 21. The transcription factor SP7 was the highest gene modulated by the biomaterial with a 3 Log 2 fold increase. It has been reported that during the development of the skeletal bone and tooth, SP7 is a key mesenchymal factor necessary for cell fate decisions in the differentiation of specialized cells. Down-regulated genes were that encoding ECM and cell-to cell adhesion molecules such as BGN, CDH11, COL1A1, COL5A1, COMP, CSF2, CTSK, IGF1/2, IGF1R, ALPL. Early transcription factors, such as RUNX2, SMAD1, TWIST1 were down-regulated, at day 21. In addition, FGFR2 and BMPR2 genes were also down-regulated compared to the control. Discussion. Our data demonstrate that the innovative scaffold provides a good microenvironment for the hMSCs adhesion and proliferation. The scaffold demonstrated biocompatibility in term of morphology, viability and cytoskeleton architecture of hMSC grown on the biomaterial. Gene expression profile analyses by array technology demonstrated that, in hMSCs, the scaffold induces up-regulation in specific genes that are involved in ossification process, such as BMP2/3, SPP1 and SP7, at d 21 post-cell seeding. The scaffold induces a up-regulation of the osteocalcin protein with improvement in matrix mineralization, indicating a good osteoinductivity performance. In conclusion, our experimental cell biology and epigenetic analyses suggest that the Coll/HA hybrid scaffold is an excellent biomaterial for the bone repair and bone tissue engineering