In Vitro Concurrent Endothelial and Osteogenic Commitment of Adipose-Derived Stem Cells and Their Genomical Analyses Through Comparative Genomic Hybridization Array: Novel Strategies to Increase the Successful Engraftment of Tissue-Engineered Bone Grafts

CaCO3 from Anadara granosa shell as reparative dentin inducer in odontoblast pulp cells: In-vivo study

Introduction

Anadara granosa (blood clam) shell contained 98.7% of calcium carbonate (CaCO3). This material has bio-properties that able to induced the dentin regeneration. This study is expected to reveal the nuclear factor kappa beta (NF-kB), transforming growth factor beta (TGF-β1), and vascular endothelial growth factor A (VEGF-A) expression in dental pulp after application of CaCO3 from Anadara granosa shell.

Material and methods

The thirty Rattus norvegicus strain Wistar used as model. The maxillary first molar was preparation using 0.84 mm low-speed diamond bur to made cavity. The cavity then applied glass ionomer cement (as control group) and other group applied CaCO3 from Anadara granosa shell. The teeth in each group were extracted after 1st, 3rd and 7th days of application for immunohistochemistry analysis for NF-kB, TGF-β1, and VEGF-A expression.

Result

The NF-kB expression in the group with CaCO3 from Anadara granosa shell lower than control after 1st, 3rd and 7th days (p < 0.05). In other hand, the TGF-β1 and VEGF-A expression in the group with CaCO3 from Anadara granosa shell higher than control after 1st, 3rd and 7th days (p < 0.05).

Conclusion

CaCO3 from Anadara granosa shell able to stimulate the TGF-β1 and VEGF-A and suppress the NF-kB expression in the dental pulp. This material able to develop as dentin-pulp material restoration.

Playing with Biophysics: How a Symphony of Different Electromagnetic Fields Acts to Reduce the Inflammation in Diabetic Derived Cells

Several factors, such as ischemia, infection and skin injury impair the wound healing process. One common pathway in all these processes is related to the reactive oxygen species (ROS), whose production plays a vital role in wound healing. In this view, several strategies have been developed to stimulate the activation of the antioxidative system, thereby reducing the damage related to oxidative stress and improving wound healing. For this purpose, complex magnetic fields (CMFs) are used in this work on fibroblast and monocyte cultures derived from diabetic patients in order to evaluate their influence on the ROS production and related wound healing properties. Biocompatibility, cytotoxicity, mitochondrial ROS production and gene expression have been evaluated. The results confirm the complete biocompatibility of the treatment and the lack of side effects on cell physiology following the ISO standard indication. Moreover, the results confirm that the CMF treatment induced a reduction in the ROS production, an increase in the macrophage M2 anti-inflammatory phenotype through the activation of miRNA 5591, a reduction in inflammatory cytokines, such as interleukin-1 (IL-1) and IL-6, an increase in anti-inflammatory ones, such as IL-10 and IL-12 and an increase in the markers related to improved wound healing such as collagen type I and integrins. In conclusion, our findings encourage the use of CMFs for the treatment of diabetic foot.

PEEK and Hyaluronan-Based 3D Printed Structures: Promising Combination to Improve Bone Regeneration

Hybrid bone substitute made up of a 3D printed polyetheretherketone (PEEK) scaffold coated with methacrylated hyaluronic acid (MeHA)-hydroxyapatite (HAp) hydrogel is the objective of the present work. Development and characterization of the scaffold and of the MeHA-HAp after its infiltration and UV photocrosslinking have been followed by analyses of its biological properties using human mesenchymal stem cells (MSCs). Interconnected porous PEEK matrices were produced by fused deposition modeling (FDM) characterized by a reticular pattern with 0°/90° raster orientation and square pores. In parallel, a MeHA-HAp slurry has been synthesized and infiltrated in the PEEK scaffolds. The mechanical properties of the coated and pure PEEK scaffold have been evaluated, showing that the inclusion of MeHA-HAp into the lattice geometry did not significantly change the strength of the PEEK structure with Young's modulus of 1034.9 ± 126.1 MPa and 1020.0 ± 63.7 MPa for PEEK and PEEK-MeHA-HAp scaffolds, respectively. Human MSCs were seeded on bare and coated scaffolds and cultured for up to 28 days to determine the adhesion, proliferation, migration and osteogenic differentiation. In vitro results showed that the MeHA-HAp coating promotes MSCs adhesion and proliferation and contributes to osteogenic differentiation and extracellular matrix mineralization. This study provides an efficient solution for the development of a scaffold combining the great mechanical performances of PEEK with the bioactive properties of MeHA and HAp, having high potential for translational clinical applications.

Apple Derived Exosomes Improve Collagen Type I Production and Decrease MMPs during Aging of the Skin through Downregulation of the NF-κB Pathway as Mode of Action

Skin ageing is strictly related to chronic inflammation of the derma and the decay of structural proteins of the extracellular matrix. Indeed, it has become common practice to refer to this phenomenon as inflammageing. Biotech innovation is always in search of new active principles that induce a youthful appearance. In this paper, apple-derived nanovesicles (ADNVs) were investigated as novel anti-inflammatory compounds, which are able to alter the extracellular matrix production of dermal fibroblasts. Total RNA sequencing analysis revealed that ADNVs negatively influence the activity of Toll-like Receptor 4 (TLR4), and, thus, downregulate the NF-κB pro-inflammatory pathway. ADNVs also reduce extracellular matrix degradation by increasing collagen synthesis (COL3A1, COL1A2, COL8A1 and COL6A1) and downregulating metalloproteinase production (MMP1, MMP8 and MMP9). Topical applications for skin regeneration were evaluated by the association of ADNVs with hyaluronic-acid-based hydrogel and patches.

In Vitro Model for the Evaluation of Innovative Transcatheter Debridement Device (TDD): Pericardium-Based Scaffold and Stem Cells to Reproduce Calcificated Valves

Aortic valve stenosis has become the most common valvular disease in elderly patients. Several treatments are available such as surgical aortic valve replacement and transcatheter aortic valve implantation. To date, however, there is a need to discover alternative treatments that can delay the disease progression and, therefore, the implant of a prosthetic valve. In this regard, a decalcification procedure based on the use of ultrasonic waves could represent an innovative solution in transcatheter cardiovascular therapies. In this article, we describe an innovative transcatheter debridement device (TDD) that uses low-intensity ultrasound shock waves for calcium ablation from the native aortic valve and bioprosthetic valve. Mesenchymal stem cells were seeded onto pericardium-based scaffolds and committed into an osteogenic phenotype. After treatment with TDD, cell proliferation was analyzed, as well as lactate dehydrogenase release and cell morphology. The release of calcium and inflammation events were detected. The results confirmed that the TDD was able to induce a safe decalcification without any adverse inflammatory events.

Dentin Particulate for Bone Regeneration: An In Vitro Study

The aim of this in vitro study was to investigate the commitment and behavior of dental pulp stem cells (DPSCs) seeded onto two different grafting materials, human dentin particulate (DP) and deproteinized bovine bone matrix (BG), with those cultured in the absence of supplements. Gene expression analyses along with epigenetic and morphological tests were carried out to examine odontogenic and osteogenic differentiation and cell proliferation. Compressive testing of the grafting materials seeded with DPSCs was performed as well. DPSC differentiation into odontoblast-like cells was identified from the upregulation of odontogenic markers (DSPP and MSX) and osteogenic markers (RUNX2, alkaline phosphatase, osteonectin, osteocalcin, collagen type I, bmp2, smad5/8). Epigenetic tests confirmed the presence of miRNAs involved in odontogenic or osteogenic commitment of DPSCs cultured for up to 21 days on DP. Compressive strength values obtained from extracellular matrix (ECM) synthesized by DPSCs showed a trend of being higher when seeded onto DP than onto BG. High expression of VEGF factor, which is related to angiogenesis, and of dentin sialoprotein was observed only in the presence of DP. Morphological analyses confirmed the typical phenotype of adult odontoblasts. In conclusion, the odontogenic and osteogenic commitment of DPSCs and their respective functions can be achieved on DP, which enables exceptional dentin and bone regeneration.

The Impact of Graphene Oxide on Polycaprolactone PCL Surfaces: Antimicrobial Activity and Osteogenic Differentiation of Mesenchymal Stem Cell

In dentistry, bone regeneration requires osteoinductive biomaterial with antibacterial properties. Polycaprolactone (PCL) may be combined with different nanofillers including reduced graphene oxide (rGO). Here, the amount of rGO filler was defined to obtain a biocompatible and antibacterial PCL-based surface supporting the adhesion and differentiation of human mesenchymal stem cells (MSCs). Compounds carrying three different percentages of rGO were tested. Among all, the 5% rGO-PCL compound is the most bacteriostatic against Gram-positive bacteria. All scaffolds are biocompatible. MSCs adhere and proliferate on all scaffolds; however, 5% rGO-PCL surface supports the growth of cells and implements the expression of extracellular matrix components necessary to anchor the cells to the surface itself. Moreover, the 5% rGO-PCL surface has superior osteoinductive properties confirmed by the improved alkaline phosphatase activity, mineral matrix deposition, and osteogenic markers expression. These results suggest that 5% rGO-PCL has useful properties for bone tissue engineering purposes.

Exosomes Derived from Dental Pulp Stem Cells Show Different Angiogenic and Osteogenic Properties in Relation to the Age of the Donor

Craniofacial tissue reconstruction still represents a challenge in regenerative medicine. Mesenchymal stem cell (MSC)-based tissue engineering strategies have been introduced to enhance bone tissue repair. However, the risk of related complications is limiting their usage. To overcome these drawbacks, exosomes (EXOs) derived from MSCs have been recently proposed as a cell-free alternative to MSCs to direct tissue regeneration. It was hypothesized that there is a correlation between the biological properties of exosomes derived from the dental pulp and the age of the donor. The aim of the study was to investigate the effect of EXOs derived from dental pulp stem cells of permanent teeth (old donor group) or exfoliated deciduous teeth (young donor group) on MSCs cultured in vitro. Proliferation potential was evaluated by doubling time, and commitment ability by gene expression and biochemical quantification for tissue-specific factors. Results showed a well-defined proliferative influence for the younger donor aged group. Similarly, a higher commitment ability was detected in the young group. In conclusion, EXOs could be employed to promote bone regeneration, likely playing an important role in neo-angiogenesis in early healing phases.

Stem Cells in Autologous Microfragmented Adipose Tissue: Current Perspectives in Osteoarthritis Disease

Osteoarthritis (OA) is a chronic debilitating disorder causing pain and gradual degeneration of weight-bearing joints with detrimental effects on cartilage volume as well as cartilage damage, generating inflammation in the joint structure. The etiology of OA is multifactorial. Currently, therapies are mainly addressing the physical and occupational aspects of osteoarthritis using pharmacologic pain treatment and/or surgery to manage the symptomatology of the disease with no specific regard to disease progression or prevention. Herein, we highlight alternative therapeutics for OA specifically considering innovative and encouraging translational methods with the use of adipose mesenchymal stem cells.

Biological Characterization of Human Autologous Pericardium Treated with the Ozaki Procedure for Aortic Valve Reconstruction

Background: The Ozaki procedure is an innovative surgical technique aiming at reconstructing aortic valves with human autologous pericardium. Even if this procedure is widely used, a comprehensive biological characterization of the glutaraldehyde (GA)-fixed pericardial tissue is still missing. Methods: Morphological analysis was performed to assess the general organization of pericardium subjected to the Ozaki procedure (post-Ozaki) in comparison to native tissue (pre-Ozaki). The effect of GA treatment on cell viability and nuclear morphology was then investigated in whole biopsies and a cytotoxicity assay was executed to assess the biocompatibility of pericardium. Finally, human umbilical vein endothelial cells were seeded on post-Ozaki samples to evaluate the influence of GA in modulating the endothelialization ability in vitro and the production of pro-inflammatory mediators. Results: The Ozaki procedure alters the arrangement of collagen and elastic fibers in the extracellular matrix and results in a significant reduction in cell viability compared to native tissue. GA treatment, however, is not cytotoxic to murine fibroblasts as compared to a commercially available bovine pericardium membrane. In addition, in in vitro experiments of endothelial cell adhesion, no difference in the inflammatory mediators with respect to the commercial patch was found. Conclusions: The Ozaki procedure, despite alteration of ECM organization and cell devitalization, allows for the establishment of a noncytotoxic environment in which endothelial cell repopulation occurs.

In Vitro Cultures of Adipose-Derived Stem Cells: An Overview of Methods, Molecular Analyses, and Clinical Applications

Adipose-derived stem cells (ASCs) exhibiting mesenchymal stem cell (MSC) characteristics, have been extensively studied in recent years. Because they have been shown to differentiate into lineages such as osteogenic, chondrogenic, neurogenic or myogenic, the focus of most of the current research concerns either their potential to replace bone marrow as a readily available and abundant source of MSCs, or to employ them in regenerative and reconstructive medicine. There is close to consensus regarding the methodology used for ASC isolation and culture, whereas a number of molecular analyses implicates them in potential therapies of a number of pathologies. When it comes to clinical application, there is a range of examples of animal trials and clinical studies employing ASCs, further emphasizing the advancement of studies leading to their more widespread use. Nevertheless, in vitro studies will most likely continue to play a significant role in ASC studies, both providing the molecular knowledge of their ex vivo properties and possibly serving as an important step in purification and application of those cells in a clinical setting. Therefore, it is important to consider current methods of ASC isolation, culture, and processing. Furthermore, molecular analyses and cell surface properties of ASCs are essential for animal studies, clinical studies, and therapeutic applications of the MSC properties.

The Impact of Bioceramic Scaffolds on Bone Regeneration in Preclinical In Vivo Studies: A Systematic Review

Bioceramic scaffolds are appealing for alveolar bone regeneration, because they are emerging as promising alternatives to autogenous and heterogenous bone grafts. The aim of this systematic review is to answer to the focal question: in critical-sized bone defects in experimental animal models, does the use of a bioceramic scaffolds improve new bone formation, compared with leaving the empty defect without grafting materials or using autogenous bone or deproteinized bovine-derived bone substitutes? Electronic databases were searched using specific search terms. A hand search was also undertaken. Only randomized and controlled studies in the English language, published in peer-reviewed journals between 2013 and 2018, using critical-sized bone defect models in non-medically compromised animals, were considered. Risk of bias assessment was performed using the SYRCLE tool. A meta-analysis was planned to synthesize the evidence, if possible. Thirteen studies reporting on small animal models (six studies on rats and seven on rabbits) were included. The calvarial bone defect was the most common experimental site. The empty defect was used as the only control in all studies except one. In all studies the bioceramic materials demonstrated a trend for better outcomes compared to an empty control. Due to heterogeneity in protocols and outcomes among the included studies, no meta-analysis could be performed. Bioceramics can be considered promising grafting materials, though further evidence is needed.

Autologous Fat Transfer for Facial Augmentation: Surgery and Regeneration

Autologous fat transfer (AFT) is a well-established and safe surgical technique in which autologous fat tissue is injected at a defective site directly after its harvesting and centrifugation. Initially used as an excellent filler for facial enhancement and rejuvenation, AFT has evolved over the years into more complex reconstructive procedures. Autologous fat transfer is now additionally used for correcting and restoring cranial and maxillofacial volume defects resulting from traumas, tumors, or congenital disorders. Apart from being a natural filler, human adipose tissue represents a rich source of mesenchymal stem cells, called adipose-derived stem cells, that exhibit multilineage differentiation potential and secrete several angiogenic and antiapoptotic factors.In this work, the authors will discuss different aspects influencing the final outcome of AFT, on the basis of the major clinical outcomes obtained using this surgical procedure. Starting from preoperative evaluation and planning, donor-recipient sites, and type of anesthesia and infiltration, the discussion will continue by analyzing the methods of adipose tissue harvesting, purification, and processing. Finally, an overview of the type of placement, clinical application, postoperative care, possible complications, fat graft take, longevity, volume maintenance, and future perspectives will be provided.

Metal Nanoparticles Released from Dental Implant Surfaces: Potential Contribution to Chronic Inflammation and Peri-Implant Bone Loss

Peri-implantitis is an inflammatory disease affecting tissues surrounding dental implants. Although it represents a common complication of dental implant treatments, the underlying mechanisms have not yet been fully described. The aim of this study is to identify the role of titanium nanoparticles released form the implants on the chronic inflammation and bone lysis in the surrounding tissue. We analyzed the in vitro effect of titanium (Ti) particle exposure on mesenchymal stem cells (MSCs) and fibroblasts (FU), evaluating cell proliferation by MTT test and the generation of reactive oxygen species (ROS). Subsequently, in vivo analysis of peri-implant Ti particle distribution, histological, and molecular analyses were performed. Ti particles led to a time-dependent decrease in cell viability and increase in ROS production in both MSCs and FU. Tissue analyses revealed presence of oxidative stress, high extracellular and intracellular Ti levels and imbalanced bone turnover. High expression of ZFP467 and the presence of adipose-like tissue suggested dysregulation of the MSC population; alterations in vessel morphology were identified. The results suggest that Ti particles may induce the production of high ROS levels, recruiting abnormal quantity of neutrophils able to produce high level of metalloproteinase. This induces the degradation of collagen fibers. These events may influence MSC commitment, with an imbalance of bone regeneration.

Bioactive Sphene-Based Ceramic Coatings on cpTi Substrates for Dental Implants: An In Vitro Study

Titanium implant surface modifications have been widely investigated to favor the process of osseointegration. The present work aimed to evaluate the effect of sphene (CaTiSiO₅) biocoating, on titanium substrates, on the in vitro osteogenic differentiation of Human Adipose-Derived Stem Cells (hADSCs). Sphene bioceramic coatings were prepared using preceramic polymers and nano-sized active fillers and deposited by spray coating. Scanning Electron Microscopy (SEM) analysis, surface roughness measurements and X-ray diffraction analysis were performed. The chemical stability of the coatings in Tris-HCl solution was investigated. In vitro studies were performed by means of proliferation test of hADSCs seeded on coated and uncoated samples after 21 days. Methyl Thiazolyl-Tetrazolium (MTT) test and immunofluorescent staining with phalloidin confirmed the in vitro biocompatibility of both substrates. In vitro osteogenic differentiation of the cells was evaluated using Alizarin Red S staining and quantification assay and real-time PCR (Polymerase Chain Reaction). When hADSCs were cultured in the presence of Osteogenic Differentiation Medium, a significantly higher accumulation of calcium deposits onto the sphene-coated surfaces than on uncoated controls was detected. Osteogenic differentiation on both samples was confirmed by PCR. The proposed coating seems to be promising for dental and orthopedic implants, in terms of composition and deposition technology.

A Non-Enzymatic Method to Obtain a Fat Tissue Derivative Highly Enriched in Adipose Stem Cells (ASCs) from Human Lipoaspirates: Preliminary Results

Adipose tissue possesses phenotypic gene expression characteristics that are similar to human mesenchymal stem cells (hMSCs). Nevertheless, the multilineage potential may be inhibited, and cells may not expand adequately to satisfy the requirements of Good Manufacturing Practice (cGMP). An autologous hMSC-enriched fat product would fulfil the void from a biomedical and clinical perspective. In this study, we suggest a novel mechanism using a closed system without enzymes, additives or other modifications, which will produce non-expanded, accessible material. This decentralized fat product, unlike unprocessed lipoaspirates, adequately encloses the vascular stroma with adipocytes and stromal stalks along with their vascular channels and lumina. This fat product contained hASCs and fewer hematopoietic elements such as lipoaspirates, which were digested enzymatically according to flow cytometric investigations, and molecular analysis also showed significant hASC uniformity within the cells of the stromal vascular tissue. Moreover, the fat product produced a higher quantity of hASCs similar to hMSCs in isolation with the typical characteristics of an osteogenic, chondrogenic and adipogenic lineage. Interestingly, these properties were evident in the non-enzymatic derived adipose tissue, as opposed to hASCs in isolation from the enzymatically digested lipoaspirates, suggesting that the aforementioned procedure may be an adequate alternative to regenerate and engineer tissue for the treatment of various medical conditions and promote efficient patient recovery.

The Biological Properties of OGI Surfaces Positively Act on Osteogenic and Angiogenic Commitment of Mesenchymal Stem Cells

Osteogenesis process displays a fundamental role during dental implant osteointegration. In the present work, we studied the influence of Osteon Growth Induction (OGI) surface properties on the angiogenic and osteogenic behaviors of Mesenchymal Stem cells (MSC). MSC derived from dental pulp and HUVEC (Human Umbilical Vein Endothelial Cells) were grown in on OGI titanium surfaces, and cell proliferation and DNA synthesis were evaluated by MTT [3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide] test and DNA quantification. Gene expression has been performed in order to evaluate the presence of mRNA related to endothelial and osteogenesis markers. Moreover, morphological and biochemical analyses of osteogenesis commitments has been performed. On OGI surfaces, MSC and HUVEC are able to proliferate. Gene expression profiler confirms that MSC on OGI surfaces are able to express endothelial and osteogenic markers, and that these expression are higher compared the expression on control surfaces. In conclusion On OGI surfaces proliferation, expression and morphological analyses of angiogenesis-associated markers in MSC are promoted. This process induces an increasing on their osteogenesis commitment.

Non-Washed Resorbable Blasting Media (NWRBM) on Titanium Surfaces could Enhance Osteogenic Properties of MSCs through Increase of miRNA-196a And VCAM1

Surface topography of Titanium (Ti) dental implants strongly influences osseointegration. In the present work, we have analyzed the influence of two Ti implant surfaces characterized by similar microtopography but different nanotopography and chemistry on the osteoblastic phenotype of Dental Pulp Stem Cells (DPSCs). The effect on osteogenic differentiation, extracellular matrix (ECM) and cell adhesion molecules production have been evaluated by means of molecular biology analyses. The morphology of the cells grown onto these surfaces has been analyzed with SEM and immunofluorescence (IF), and the safety of the surfaces has been tested by using karyotype analysis, Ames test and hemocompatibility assay. Results showed that starting from 15 days of DPSCs culture, a substantial expression of osteoblast specific markers and a strong increase of cell adhesion molecules can be detected. In particular, when DPSCs are seeded on the Ti implants expression of microRNA (miRNA)-196a, which is involved in osteoblastic commitment of stem cells, and of Vascular Cell Adhesion Molecule 1 (VCAM1), a factor involved in angiogenesis, is strongly enhanced.

Release of VEGF from Dental Implant Improves Osteogenetic Process: Preliminary In Vitro Tests

Introduction: During osseointegration process, the presence of an inflammatory event could negatively influence the proper osteogenetic ability of the implant surface. In order to reduce this possibility, an implementation of angiogenetic event through the release of Vascular Endothelial Growth Factor (VEGF) can be a tool as co-factor for osteoblastic differentiation. In this paper, novel dental implant surfaces enriched with VEGF have been tested. Material and methods: The ability of VEGF-enriched titanium implants to improve the osteogenetic properties of Mesenchymal stem cells (MSC), also in the presence of an inflammatory environment, have been in vitro tested. Molecular biology, morphological analyses, and biochemical tests have been performed in order to confirm biological properties of these surfaces. Results: Our results confirm that the presence of VEGF onto the implant surface is able not only to protect the cells from in vitro aging and from Reactive Oxygen Species (ROS) damage, but it also improves their osteogenic and endothelial differentiation, even in the presence of inflammatory cytokines. Conclusion: This study establishes a biologically powerful novel tool that could enhance bone repair in dental implant integration.

Porcine Bone Scaffolds Adsorb Growth Factors Secreted by MSCs and Improve Bone Tissue Repair

An ideal tissue-engineered bone graft should have both excellent pro-osteogenesis and pro-angiogenesis properties to rapidly realize the bone regeneration in vivo. To meet this goal, in this work a porcine bone scaffold was successfully used as a Trojan horse to store growth factors produced by mesenchymal stem cells (MSCs). This new scaffold showed a time-dependent release of bioactive growth factors, such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), in vitro. The biological effect of the growth factors-adsorbed scaffold on the in vitro commitment of MSCs into osteogenic and endothelial cell phenotypes has been evaluated. In addition, we have investigated the activity of growth factor-impregnated granules in the repair of critical-size defects in rat calvaria by means of histological, immunohistochemical, and molecular biology analyses. Based on the results of our work bone tissue formation and markers for bone and vascularization were significantly increased by the growth factor-enriched bone granules after implantation. This suggests that the controlled release of active growth factors from porcine bone granules can enhance and promote bone regeneration.

Coculture effects on the osteogenic differentiation of human mesenchymal stromal cells

Cell-based bone regeneration is generally pursued based on single cell type approaches, for which human adipose tissue-derived mesenchymal stromal cells (AT-MSCs) are frequently used, owing to their easy accessibility and relatively large yield. In view of multiple cell types involved in physiological bone regeneration, this study aimed to evaluate the osteogenic differentiation of AT-MSCs upon co-culture with endothelial cells or macrophages in a direct or indirect in vitro co-culture set-up. Our hypotheses were that 1) endothelial cells and macrophages stimulate AT-MSCs proliferation and osteogenic differentiation and that 2) these two cell types will more profoundly affect osteogenic differentiation of AT-MSCs in a direct compared to an indirect co-culture set-up, because of the possibility for both cell-cell interactions and effects of secreted soluble factors in the former. Osteogenic differentiation of AT-MSCs was stimulated by endothelial cells, particularly in direct co-cultures. Although initial numbers of AT-MSCs in co-culture with endothelial cells were 50% compared to monoculture controls, equal levels of mineralization were achieved. Macrophages showed a variable effect on AT-MSCs behavior for indirect co-cultures and a negative effect on osteogenic differentiation of AT-MSCs in direct co-cultures, the latter likely due to species differences of the cell types used. The results of this study demonstrate potential for cell combination strategies in bone regenerative therapies.

Osteo Growth Induction titanium surface treatment reduces ROS production of mesenchymal stem cells increasing their osteogenic commitment

Surface characteristics play a special role for the biological performance of implants and several strategies are available to this end. The OGI (Osteo Growth Induction) titanium surface is a surface, obtained by applying a strong acid onto the blasted surface. The aim of this in-vitro study is to evaluate in vitro the osteoproperties of OGI surfaces on Mesenchymal Stem cells derived from dental pulp. Our results confirm that this treatment exert a positive effect on mitochondrial homeostasis, as shown by a decrease in ROS production related to environmental stress on the mitochondria. Morphological and molecular biology analyses confirmed more over that the DPSC cultured on the OGI surfaces appeared more spread in comparison to those grown on control titanium surface and real time PCR and biochemical data clearly demonstrated the increase of osteoconductive properties of the OGI treatment. In conclusion, our results suggest that mesenchymal stem cells sensitively respond to surface properties related to OGI treatment enhancing their osteogenic activities.

Cell Cotransplantation Strategies for Vascularized Craniofacial Bone Tissue Engineering: A Systematic Review and Meta-Analysis of Preclinical In Vivo Studies

The regenerative potential of tissue-engineered bone constructs may be enhanced by in vitro coculture and in vivo cotransplantation of vasculogenic and osteogenic (progenitor) cells. The objective of this study was to systematically review the literature to answer the focused question: In animal models, does cotransplantation of osteogenic and vasculogenic cells enhance bone regeneration in craniofacial defects, compared with solely osteogenic cell-seeded constructs? Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, electronic databases were searched for controlled animal studies reporting cotransplantation of endothelial cells (ECs) with mesenchymal stem cells (MSCs) or osteoblasts in craniofacial critical size defect (CSD) models. Twenty-two studies were included comparing outcomes of MSC/scaffold versus MSC+EC/scaffold (co)transplantation in calvarial (n = 15) or alveolar (n = 7) CSDs of small (rodents, rabbits) and large animal (minipigs, dogs) models. On average, studies presented with an unclear to high risk of bias. MSCs were derived from autologous, allogeneic, xenogeneic, or human (bone marrow, adipose tissue, periosteum) sources; in six studies, ECs were derived from MSCs by endothelial differentiation. In most studies, MSCs and ECs were cocultured in vitro (2-17 days) before implantation. Coculture enhanced MSC osteogenic differentiation and an optimal MSC:EC seeding ratio of 1:1 was identified. Alloplastic copolymer or composite scaffolds were most often used for in vivo implantation. Random effects meta-analyses were performed for histomorphometric and radiographic new bone formation (%NBF) and vessel formation in rodents' calvarial CSDs. A statistically significant benefit in favor of cotransplantation versus MSC-only transplantation for radiographic %NBF was observed in rat calvarial CSDs (weighted mean difference 7.80% [95% confidence interval: 1.39-14.21]); results for histomorphometric %NBF and vessel formation were inconclusive. Overall, heterogeneity in the meta-analyses was high (I² > 80%). In summary, craniofacial bone regeneration is enhanced by cotransplantation of vasculogenic and osteogenic cells. Although the direction of treatment outcome is in favor of cotransplantation strategies, the magnitude of treatment effect does not seem to be of relevance, unless proven otherwise in clinical studies.

Autologous adipose-derived stem cells: Basic science, technique, and rationale for application in ulcer and wound healing

Objectives The present review represents a translational boundary between basic research and surgery, particularly focusing on the promising application of adipose-derived stem cells harvested intra-operatively during debridement of venous leg ulcers. Methods We reviewed 830 out of 5578 articles on MEDLINE starting from 1997 and sorted by the relevance option. Results The technique currently used for adipose-derived stem cells intra-operative harvesting is presented, including a safety evaluation on a cohort of 5089 revised patients who underwent plastic surgery and maxillo-facial surgical procedures. Complications were reported in 169 cases (3.3%). One hundred and forty-one (2.77%) patients were classified as having minor complications, specifically: nodularity/induration 93 (1.83%), dysesthesia 14 (0.26%), hematoma 12 (0.23%), superficial infection 11 (0.21%), pain 7 (0.13%), poor cosmesis 3 (0.06%), and abnormal breast secretion 1 (0.02%), while 28 patients (0.55%) were classified as having major complications, specifically: deep infection 22 (0.43%), sepsis 3 (0.06%), abdominal hematoma 2 (0.04%), and pneumothorax 1 (0.02%). Application of cell therapy in venous leg ulcer is currently used only for patients not responding to the standard treatment. The review shows the lack of randomized clinical trials for application of adipose-derived stem cells among treatments for venous leg ulcer. Finally, adipose-derived stem cells implantation at the wound site promotes a new tissue formation rich in vascular structures and remodeling collagen. Conclusion Adipose-derived stem cells strategy represents a great opportunity for the treatment of chronic wounds, due to the simplicity of the technique and the application of cell treatment in the operating room immediately following debridement. However, clinical studies and data from randomized trials are currently lacking.

Decellularization and Delipidation Protocols of Bovine Bone and Pericardium for Bone Grafting and Guided Bone Regeneration Procedures

The combination of bone grafting materials with guided bone regeneration (GBR) membranes seems to provide promising results to restore bone defects in dental clinical practice. In the first part of this work, a novel protocol for decellularization and delipidation of bovine bone, based on multiple steps of thermal shock, washes with detergent and dehydration with alcohol, is described. This protocol is more effective in removal of cellular materials, and shows superior biocompatibility compared to other three methods tested in this study. Furthermore, histological and morphological analyses confirm the maintenance of an intact bone extracellular matrix (ECM). In vitro and in vivo experiments evidence osteoinductive and osteoconductive properties of the produced scaffold, respectively. In the second part of this study, two methods of bovine pericardium decellularization are compared. The osmotic shock-based protocol gives better results in terms of removal of cell components, biocompatibility, maintenance of native ECM structure, and host tissue reaction, in respect to the freeze/thaw method. Overall, the results of this study demonstrate the characterization of a novel protocol for the decellularization of bovine bone to be used as bone graft, and the acquisition of a method to produce a pericardium membrane suitable for GBR applications.

Recent Advances in Hydroxyapatite Scaffolds Containing Mesenchymal Stem Cells

Modern day tissue engineering and cellular therapies have gravitated toward using stem cells with scaffolds as a dynamic modality to aid in differentiation and tissue regeneration. Mesenchymal stem cells (MSCs) are one of the most studied stem cells used in combination with scaffolds. These cells differentiate along the osteogenic lineage when seeded on hydroxyapatite containing scaffolds and can be used as a therapeutic option to regenerate various tissues. In recent years, the combination of hydroxyapatite and natural or synthetic polymers has been studied extensively. Due to the interest in these scaffolds, this review will cover the wide range of hydroxyapatite containing scaffolds used with MSCs for in vitro and in vivo experiments. Further, in order to maintain a progressive scope of the field this review article will only focus on literature utilizing adult human derived MSCs (hMSCs) published in the last three years.

Adipose tissue-derived mesenchymal stem cells as monocultures or cocultures with human umbilical vein endothelial cells: performance in vitro and in rat cranial defects

The aim of this study was to compare the osteogenic capacity between human adipose tissue-derived mesenchymal stem cells (AT-MSCs) and their cocultures with human umbilical vein endothelial cells (HUVECs) in vitro and their biological performance in vivo. First, the optimal cell ratio in cocultures for osteogenic differentiation was determined by seeding AT-MSCs and HUVECs in ratios varying from 100:0 to 0:100 on tissue culture plates. Afterward, AT-MSCs and AT-MSCs/HUVECs (50:50) were seeded on porous titanium fiber mesh scaffolds (Ti) for both in vitro and in vivo osteogenic evaluation. For in vitro evaluation, cell osteogenic differentiation was assessed by alkaline phosphatase (ALP) activity and calcium assay. For in vivo evaluation, the scaffolds were implanted bilaterally into rat cranial defects (5 mm diameter) and bone formation was assessed histologically and histomorphometrically after 8 weeks. The ratio of 50:50 was chosen in the cocultures because this coculture condition retained similar amount of calcium deposition while using the least amount of AT-MSCs. Moreover, AT-MSCs showed higher osteogenic differentiation in comparison to AT-MSCs/HUVECs on Ti in vitro. Furthermore, superior bone formation was observed in AT-MSCs compared to AT-MSCs/HUVECs in rat cranial defects. In conclusion, AT-MSCs showed significantly higher osteogenic potential compared to AT-MSCs/HUVECs both in vitro and in vivo.

Platelet-derived growth factor and spatiotemporal cues induce development of vascularized bone tissue by adipose-derived stem cells

Vasculature is essential to the functional integration of a tissue-engineered bone graft to enable sufficient nutrient delivery and viability after implantation. Native bone and vasculature develop through intimately coupled, tightly regulated spatiotemporal cell-cell signaling. The complexity of these developmental processes has been a challenge for tissue engineers to recapitulate, resulting in poor codevelopment of both bone and vasculature within a unified graft. To address this, we cultured adipose-derived stromal/stem cells (ASCs), a clinically relevant, single cell source that has been previously investigated for its ability to give rise to vascularized bone grafts, and studied the effects of initial spatial organization of cells, the temporal addition of growth factors, and the presence of exogenous platelet-derived growth factor-BB (PDGF-BB) on the codevelopment of bone and vascular tissue structures. Human ASCs were aggregated into multicellular spheroids via the hanging drop method before encapsulation and subsequent outgrowth in fibrin gels. Cellular aggregation substantially increased vascular network density, interconnectivity, and pericyte coverage compared to monodispersed cultures. To form robust vessel networks, it was essential to culture ASCs in a purely vasculogenic medium for at least 8 days before the addition of osteogenic cues. Physiologically relevant concentrations of exogenous PDGF-BB (20 ng/mL) substantially enhanced both vascular network stability and osteogenic differentiation. Comparisons with the bone morphogenetic protein-2, another pro-osteogenic and proangiogenic growth factor, indicated that this potential to couple the formation of both lineages might be unique to PDGF-BB. Furthermore, the resulting tissue structure demonstrated the close association of mineral deposits with pre-existing vascular structures that have been described for developing tissues. This combination of a single cell source with a potent induction factor used at physiological concentrations can provide a clinically relevant approach to engineering highly vascularized bone grafts.

Donor age-related biological properties of human dental pulp stem cells change in nanostructured scaffolds

The aim of the present work is to study how biological properties, such as proliferation and commitment ability, of human adult dental pulp stem cells (DPSCs) relate to the age of the donor. Human dental pulps were extracted from molars of healthy adult subjects aged 16 to >66 years. DPSCs were isolated and cultured in the presence of osteogenic, neurogenic, or vasculogenic differentiation medium. Proliferation ability was evaluated by determining doubling time, and commitment ability was evaluated by gene expression and morphological analyses for tissue-specific markers. The results confirm a well-defined proliferative ability for each donor age group at an early in vitro passage (p2). DPSCs from younger donors (up to 35 years) maintain this ability in long-term cultures (p8). Stem cells of all age donor groups maintain their commitment ability during in vitro culture. In vivo tests on the critical size defect repair process confirmed that DPSCs of all donor ages are a potent tool for bone tissue regeneration when mixed with 3D nanostructured scaffolds.

Human adipose-derived stem cells and three-dimensional scaffold constructs: a review of the biomaterials and models currently used for bone regeneration

In the past decade, substantial strides have been taken toward the use of human adipose-derived stromal/stem cells (hASC) in the regeneration of bone. Since the discovery of the hASC osteogenic potential, many models have combined hASC with biodegradable scaffold materials. In general, rats and immunodeficient (nude) mice models for nonweight bearing bone formation have led the way to assess hASC osteogenic potential in vivo. The goal of this review is to present an overview of the recent literature describing hASC osteogenesis in conjunction with three-dimensional scaffolds for bone regeneration.

Human adipose-derived cells can serve as a single-cell source for the in vitro cultivation of vascularized bone grafts

Orthopaedic surgery often requires bone grafts to correct large defects resulting from congenital defects, surgery or trauma. Great improvements have been made in the tissue engineering of bone grafts. However, these grafts lack the vascularized component that is critical for their survival and function. From a clinical perspective, it would be ideal to engineer vascularized bone grafts starting from one single-cell harvest obtained from the patient. To this end, we explored the potential of human adipose-derived mesenchymal stem cells (hASCs) as a single-cell source for osteogenic and endothelial differentiation and the assembly of bone and vascular compartments within the same scaffold. hASCs were encapsulated in fibrin hydrogel as an angioinductive material for vascular formation, combined with a porous silk fibroin sponge to support osteogenesis, and subjected to sequential application of growth factors. Three strategies were evaluated by changing spatiotemporal cues: (a) induction of osteogenesis prior to vasculogenesis; (b) induction of vasculogenesis prior to osteogenesis; or (c) simultaneous induction of osteogenesis and vasculogenesis. By 5 weeks of culture, bone-like tissue development was evidenced by the deposition of bone matrix proteins, alkaline phosphatase activity and calcium deposition, along with the formation of vascular networks, evidenced by endothelial cell surface markers, such as CD31 and von Willebrand factor, and morphometric analysis. Most robust development of the two tissue compartments was achieved by sequential induction of osteogenesis followed by the induction of vasculogenesis. Taken together, the collected data strongly support the utility of hASCs as a single-cell source for the formation of vascularized bone tissue.