CCL5/RANTES is important for inducing osteogenesis of human mesenchymal stem cells and is regulated by dexamethasone

Phenotypic changes associated with continuous long term in vitro expansion of bone marrow-derived mesenchymal stem cells

In vitro expansion of mesenchymal stem cells is necessary to obtain a higher cell number for clinical applications. However, long-term expansion can produce significant phenotypic changes on these cells, decreasing their therapeutic utility. Therefore, understanding the phenotypic changes that long-term expansion triggers in mesenchymal stem cells will allow for better and more consistent cell therapy results. Here, we evaluate the phenotypic changes caused by continuous passaging through colony forming unit-fibroblast assay, senescence beta-galactosidase staining, morphology examination, secretome analysis, surface marker expression, protein quantification, osteogenic and adipogenic differentiation, and CD4+ T lymphocyte immunosuppressive potential. Long-term in vitro culture decreases mesenchymal stem cell osteogenic potential and self-renewal, increases cell size, and senescence, but does not consistently affect adipogenic differentiation. Surface marker expression remains similar for positive and negative markers, while secretory phenotype shifts with decreased p14ARF, MMP-3, p21 Waf1/Cip1,ENA-78, GCP-2, GROα, IL-3, IL-7, IL-8, RANTES, TNFβ, and VEGF-A expression, and increased p53, p16 INK4a, MCP-1, and SDF-1 expression. Immunomodulatory potential remains unchanged. These findings can help better understand the phenotypic changes that mesenchymal stem cells undergo while expanded in vitro.

Platelet-Rich Fibrin (PRF) Analyzed for Cytokine Profiles - A Misguided Hope for Osteogenesis in Jawbone Defects? Research and Clinical Observational Study

Background

Platelet-rich fibrin (PRF) blood concentrates are used in oral implantology and defect surgery to promote osteoneogenesis in Bone Marrow Defects in Jawbone (BMDJ), according to the morphology of fatty-degenerative osteonecrosis also called FDOJ.

Question

Can the benefit of PRF on alveolar osteoneogenesis be confirmed by cytokine analysis?.

Methods

The cytokine expressions of the PRF samples in 26 patients undergoing BMDJ/FDOJ surgery in the same session were analysed for seven cytokines (RANTES/CCL5; FGF-2; IL-1RA; Il-6; IL-8; MCP-1; TNF-a) by multiplex (Luminex). The FDOJ samples of these 26 BMDJ/FDOJ patients were analysed for the RANTES/CCL5 expression only.

Results

Cytokine expression in PRF is compared to reference values for healthy medullary bone of the jaw and BMDJ/FDOJ and shows that the cytokine expressions of the PRF samples do not compensate or counteract prima vista for the cytokine dysregulations present in the BMDJ/FDOJ areas.

Discussion

To define the aid of cytokines studied in PRF in the restoration of the immunological dysregulation in areas of BMDJ/FDOJ, literature is reviewed comparing RANTES/CCL5, IL-1ra, TNF-α and MCP-1/CCL2 expression in PRF and BMDJ/FDOJ. Immunoregulatory properties of PRF in alveolar bone restoration are evaluated.

Summary

PRF was mistakenly thought to be a cure for bone healing, which is here shown to be incorrect. Enoral Ultrasound Sonography of bone density is available for the clinical measurement of individually developed osteoneogenesis by PRF.

Conclusion

The multiplex analysis of PRF shows a dynamic and cytokine-based interaction with osteoneogenesis that is not yet fully clarified.

Effect of Expansion Media on Functional Characteristics of Bone Marrow-Derived Mesenchymal Stromal Cells

The therapeutic efficacy of mesenchymal stromal cells (MSCs) has been shown to rely on their immunomodulatory and regenerative properties. In order to obtain sufficient numbers of cells for clinical applications, MSCs have to be expanded ex vivo. Expansion media with xenogeneic-free (XF) growth-promoting supplements like human platelet lysate (PL) or serum- and xenogeneic-free (SF/XF) formulations have been established as safe and efficient, and both groups provide different beneficial qualities. In this study, MSCs were expanded in XF or SF/XF media as well as in mixtures thereof. MSCs cultured in these media were analyzed for phenotypic and functional properties. MSC expansion was optimal with SF/XF conditions when PL was present. Metabolic patterns, consumption of growth factors, and secretome of MSCs differed depending on the type and concentration of supplement. The lactate per glucose yield increased along with a higher proportion of PL. Many factors in the supernatant of cultured MSCs showed distinct patterns depending on the supplement (e.g., FGF-2, TGFβ, and insulin only in PL-expanded MSC, and leptin, sCD40L PDGF-AA only in SF/XF-expanded MSC). This also resulted in changes in cell characteristics like migratory potential. These findings support current approaches where growth media may be utilized for priming MSCs for specific therapeutic applications.

Leveraging mice with diverse microbial exposures for advances in osteoimmunology

The skeletal and immune systems are intricately intertwined within the bone marrow microenvironment, a field of study termed osteoimmunology. Osteoimmune interactions are key players in bone homeostasis and remodeling. Despite the critical role of the immune system in bone health, virtually all animal research in osteoimmunology, and more broadly bone biology, relies on organisms with naïve immune systems. Drawing on insights from osteoimmunology, evolutionary anthropology, and immunology, this perspective proposes the use of a novel translational model: the dirty mouse. Dirty mice, characterized by diverse exposures to commensal and pathogenic microbes, have mature immune systems comparable to adult humans, while the naïve immune system of specific-pathogen free mice is akin to a neonate. Investigation into the dirty mouse model will likely yield important insights in our understanding of bone diseases and disorders. A high benefit of this model is expected for diseases known to have a connection between overactivation of the immune system and negative bone outcomes, including aging and osteoporosis, rheumatoid arthritis, HIV/AIDS, obesity and diabetes, bone marrow metastases, and bone cancers.

Functionalized Collagen/Elastin-like Polypeptide Hydrogels for Craniofacial Bone Regeneration

Critical-sized cranial bone defects fail to re-ossify and require the surgical intervention of cranioplasty. To achieve superior bone healing in such cases, a hydrogel consisting of an interpenetrating network of collagen and elastin-like polypeptide to encapsulate bone morphogenetic protein-2 (BMP-2), doxycycline, and 45S5 Bioglass is developed. This hydrogel has an appropriate elastic modulus of 39 ± 2.2 kPa to allow proper handling during implantation. The hydrogel promotes human adipose-derived stem attachment, proliferation, and differentiation toward the osteogenic lineage, including the deposition of hydroxyapatite particles embedded within a collagenous fibrillar structure after 21 days of in vitro culture. After eight weeks of implantation of the acellular hydrogel in a critical-sized rat cranial defect model, only a small quantity of various pro-inflammatory (< 20 pg mg^-1 ) and anti-inflammatory (< 10 pg mg^-1 ) factors in the adjacent cranial tissue is noticed, indicating the overall biocompatibility of the hydrogel. Scanning electron microscopy evidenced the presence of new fibrous extracellular matrix and mineral aggregates at the defect site, with calcium/phosphorus ratio of 0.5 and 2.0 by eight and twelve weeks, respectively. Microcomputed tomography (Micro-CT) and histological analyses showed formation of mature mineralized tissue that bridged with the surrounding bone. Taken together, the acellular composite hydrogel shows great promise for superior bone healing after cranioplasty.

Effects of osteogenic ambulatory mechanical stimulation on early stages of BMP-2 mediated bone repair

Purpose: Mechanical loading of bone defects through rehabilitation is a promising approach to stimulate repair and reduce nonunion risk; however, little is known about how therapeutic mechanical stimuli modulate early-stage repair before mineralized bone formation. The objective of this study was to investigate the early effects of osteogenic loading on cytokine expression and angiogenesis during the first 3 weeks of BMP-2 mediated segmental bone defect repair.Materials and Methods: A rat model of BMP-2 mediated bone defect repair was subjected to an osteogenic mechanical loading protocol using ambulatory rehabilitation and a compliant, load-sharing fixator with an integrated implantable strain sensor. The effect of fixator load-sharing on local tissue strain, angiogenesis, and cytokine expression was evaluated.Results: Using sensor readings for local measurements of boundary conditions, finite element simulations showed strain became amplified in remaining soft tissue regions between 1 and 3 weeks (Week 3: load-sharing: -1.89 ± 0.35% and load-shielded: -1.38 ± 0.35% vs. Week 1: load-sharing: -1.54 ± 0.17%; load-shielded: -0.76 ± 0.06%). Multivariate analysis of cytokine arrays revealed that load-sharing significantly altered expression profiles in the defect tissue at 2 weeks compared to load-shielded defects. Specifically, loading reduced VEGF (p = 0.052) and increased CXCL5 (LIX) levels. Subsequently, vascular volume in loaded defects was reduced relative to load-shielded defects but similar to intact bone at 3 weeks. Endochondral bone repair was also observed histologically in loaded defects at 3 weeks.Conclusions: Together, these results demonstrate that moderate ambulatory strains previously shown to stimulate bone regeneration significantly alter early angiogenic and cytokine signaling and may promote endochondral ossification.

Biomimicking Bone-Implant Interface Facilitates the Bioadaption of a New Degradable Magnesium Alloy to the Bone Tissue Microenvironment

The most critical factor determining the success of biodegradable bone implants is the host tissue response, which greatly depends on their degradation behaviors. Here, a new magnesium-based implant, namely magnesium-silicon-calcium (Mg-0.2Si-1.0Ca) alloy, that coordinates its biodegradation along with the bone regenerative process via a self-assembled, multilayered bone-implant interface is designed. At first, its rapid biocorrosion contributes to a burst release of Mg2+ , leading to a pro-osteogenic immune microenvironment in bone. Meanwhile, with the simultaneous intervention of Ca and Si in the secondary phases of the new alloy, a hierarchical layered calcified matrix is rapidly formed at the degrading interface that favored the subsequent bone mineralization. In contrast, pure Mg or Mg-0.2Si alloy without the development of this interface at the beginning will unavoidably induce detrimental bone loss. Hence, it is believed this biomimicking interface justifies its bioadaptability in which it can modulate its degradation in vivo and accelerate bone mineralization.

Influence of Dipeptidyl Peptidase-4 (DPP4) on Mesenchymal Stem-Cell (MSC) Biology: Implications for Regenerative Medicine - Review

Dipeptidyl peptidase IV (DPP4) is a ubiquitous protease that can be found in membrane-anchored or soluble form. Incretins are one of the main DPP4 substrates. These hormones regulate glucose levels, by stimulating insulin secretion and decreasing glucagon production. Because DPP4 levels are high in diabetes, DPP4 inhibitor (DPP4i) drugs derived from gliptin are widespread used as hypoglycemic agents for its treatment. However, as DPP4 recognizes other substrates such as chemokines, growth factors and neuropeptides, pleiotropic effects have been observed in patients treated with DPP4i. Several of these substrates are part of the stem-cell niche. Thus, they may affect different physiological aspects of mesenchymal stem-cells (MSC). They include viability, differentiation, mobilization and immune response. MSC are involved in tissue homeostasis and regeneration under both physiological and pathological conditions. Therefore, such cells and their secretomes have a high clinical potential in regenerative medicine. In this context, DPP4 activity may modulate different aspects of MSC regenerative capacity. Therefore, the aim of this review is to analyze the effect of different DPP4 substrates on MSC. Likewise, how the regulation of DPP4 activity by DPP4i can be applied in regenerative medicine. That includes treatment of cardiovascular and bone pathologies, cutaneous ulcers, organ transplantation and pancreatic beta-cell regeneration, among others. Thus, DPP4i has an important clinical potential as a complement to therapeutic strategies in regenerative medicine. They involve enhancing the differentiation, immunomodulation and mobilization capacity of MSC for regenerative purposes.

Altered Secretome of Diabetic Monocytes Could Negatively Influence Fracture Healing-An In Vitro Study

Diabetes mellitus is a main risk factor for delayed fracture healing and fracture non-unions. Successful fracture healing requires stimuli from different immune cells, known to be affected in diabetics. Especially, application of mononuclear cells has been proposed to promote wound and fracture healing. Thus, aim was to investigate the effect of pre-/diabetic conditions on mononuclear cell functions essential to promote osteoprogenitor cell function. We here show that pre-/diabetic conditions suppress the expression of chemokines, e.g., CCL2 and CCL8 in osteoprogenitor cells. The associated MCP-1 and MCP-2 were significantly reduced in serum of diabetics. Both MCPs chemoattract mononuclear THP-1 cells. Migration of these cells is suppressed under hyperglycemic conditions, proposing that less mononuclear cells invade the site of fracture in diabetics. Further, we show that the composition of cytokines secreted by mononuclear cells strongly differ between diabetics and controls. Similar is seen in THP-1 cells cultured under hyperinsulinemia or hyperglycemia. The altered secretome reduces the positive effect of the THP-1 cell conditioned medium on migration of osteoprogenitor cells. In summary, our data support that factors secreted by mononuclear cells may support fracture healing by promoting migration of osteoprogenitor cells but suggest that this effect might be reduced in diabetics.

Exploring the Biomaterial-Induced Secretome: Physical Bone Substitute Characteristics Influence the Cytokine Expression of Macrophages

In addition to their chemical composition various physical properties of synthetic bone substitute materials have been shown to influence their regenerative potential and to influence the expression of cytokines produced by monocytes, the key cell-type responsible for tissue reaction to biomaterials in vivo. In the present study both the regenerative potential and the inflammatory response to five bone substitute materials all based on β-tricalcium phosphate (β-TCP), but which differed in their physical characteristics (i.e., granule size, granule shape and porosity) were analyzed for their effects on monocyte cytokine expression. To determine the effects of the physical characteristics of the different materials, the proliferation of primary human osteoblasts growing on the materials was analyzed. To determine the immunogenic effects of the different materials on human peripheral blood monocytes, cells cultured on the materials were evaluated for the expression of 14 pro- and anti-inflammatory cytokines, i.e., IL-6, IL-10, IL-1β, VEGF, RANTES, IL-12p40, I-CAM, IL-4, V-CAM, TNF-α, GM-CSF, MIP-1α, Il-8 and MCP-1 using a Bio-Plex^® Multiplex System. The granular shape of bone substitutes showed a significant influence on the osteoblast proliferation. Moreover, smaller pore sizes, round granular shape and larger granule size increased the expression of GM-CSF, RANTES, IL-10 and IL-12 by monocytes, while polygonal shape and the larger pore sizes increased the expression of V-CAM. The physical characteristics of a bone biomaterial can influence the proliferation rate of osteoblasts and has an influence on the cytokine gene expression of monocytes in vitro. These results indicate that the physical structure of a biomaterial has a significant effect of how cells interact with the material. Thus, specific characteristics of a material may strongly affect the regenerative potential in vivo.

Development of systemic immune dysregulation in a rat trauma model of biomaterial-associated infection

Orthopedic biomaterial-associated infections remain a major clinical challenge, with Staphylococcus aureus being the most common pathogen. S. aureus biofilm formation enhances immune evasion and antibiotic resistance, resulting in a local, indolent infection that can persist long-term without symptoms before eventual hardware failure, bone non-union, or sepsis. Immune modulation is an emerging strategy to combat host immune evasion by S. aureus. However, most immune modulation strategies are focused on local immune responses at the site of infection, with little emphasis on understanding the infection-induced and orthopedic-related systemic immune responses of the host, and their role in local infection clearance and tissue regeneration. This study utilized a rat bone defect model to investigate how implant-associated infection affects the systemic immune response. Long-term systemic immune dysregulation was observed with a significant systemic decrease in T cells and a concomitant increase in immunosuppressive myeloid-derived suppressor cells (MDSCs) compared to non-infected controls. Further, the control group exhibited a regulated and coordinated systemic cytokine response, which was absent in the infection group. Multivariate analysis revealed high levels of MDSCs to be most correlated with the infection group, while high levels of T cells were most correlated with the control group. Locally, the infection group had attenuated macrophage infiltration and increased levels of MDSCs in the local soft tissue compared to non-infected controls. These data reveal the widespread impacts of an orthopedic infection on both the local and the systemic immune responses, uncovering promising targets for diagnostics and immunotherapies that could optimize treatment strategies and ultimately improve patient outcomes.

Influence of platelet storage time on human platelet lysates and platelet lysate-expanded mesenchymal stromal cells for bone tissue engineering

Background

Human platelet lysate (HPL) is emerging as the preferred xeno-free supplement for the expansion of mesenchymal stromal cells (MSCs) for bone tissue engineering (BTE) applications. Due to a growing demand, the need for standardization and scaling-up of HPL has been highlighted. However, the optimal storage time of the source material, i.e., outdated platelet concentrates (PCs), remains to be determined. The present study aimed to determine the optimal storage time of PCs in terms of the cytokine content and biological efficacy of HPL.

Methods

Donor-matched bone marrow (BMSCs) and adipose-derived MSCs (ASCs) expanded in HPL or fetal bovine serum (FBS) were characterized based on in vitro proliferation, immunophenotype, and multi-lineage differentiation. Osteogenic differentiation was assessed at early (gene expression), intermediate [alkaline phosphatase (ALP) activity], and terminal stages (mineralization). Using a multiplex immunoassay, the cytokine contents of HPLs produced from PCs stored for 1–9 months were screened and a preliminary threshold of 4 months was identified. Next, HPLs were produced from PCs stored for controlled durations of 0, 1, 2, 3, and 4 months, and their efficacy was compared in terms of cytokine content and BMSCs’ proliferation and osteogenic differentiation.

Results

BMSCs and ASCs in both HPL and FBS demonstrated a characteristic immunophenotype and multi-lineage differentiation; osteogenic differentiation of BMSCs and ASCs was significantly enhanced in HPL vs. FBS. Multiplex network analysis of HPL revealed several interacting growth factors, chemokines, and inflammatory cytokines. Notably, stem cell growth factor (SCGF) was detected in high concentrations. A majority of cytokines were elevated in HPLs produced from PCs stored for ≤ 4 months vs. > 4 months. However, no further differences in PC storage times between 0 and 4 months were identified in terms of HPLs’ cytokine content or their effects on the proliferation, ALP activity, and mineralization of BMSCs from multiple donors.

Conclusions

MSCs expanded in HPL demonstrate enhanced osteogenic differentiation, albeit with considerable donor variation. HPLs produced from outdated PCs stored for up to 4 months efficiently supported the proliferation and osteogenic differentiation of MSCs. These findings may facilitate the standardization and scaling-up of HPL from outdated PCs for BTE applications.

Evaluation of Osteogenic/Cementogenic Modulating Potential of PAI-1 Transfected Media for Stem Cells

AIM OF THE STUDY

In vitro evaluation of the effects of plasminogen activator inhibitor-1 (PAI-1) transfected-conditioned media (P-CM) on the differentiation of human periodontal ligament stem cells (hPDLSCs) and human periapical follicular stem cells (hPAFSCs).

MATERIALS AND METHODS

The hPDLSCs and hPAFSCs received from impacted third molars were treated with P-CM and viability, as well as differentiation of the cells were evaluated. Plasmids were constructed according to standard techniques, and all sequences were validated by proper enzyme digestion and sequencing. Chinese hamster ovarian (CHO) cells were transfected with pcDNA3.1-hPAI-1 plasmid to obtain P-CM, followed by western blotting and PAI-1-specific ELISA kit to evaluate the proteins of P-CM. The cell viability of hPDLSCs and hPAFSCs were analyzed using MTT assay after 48 h of incubation. Alizarin red S staining was performed to evaluate the differentiation of hPDLSCs and hPAFSCs. The reverse transcription-polymerase chain reaction was used to observe the expression levels of osteogenic/cementogenic marker genes. The human cytokine antibody array was applied for further analysis of cytokine expression in P-CM.

RESULTS

P-CM significantly promoted the differentiation of hPDLSCs and hPAFSCs and upregulated the expression of osteogenic/cementogenic marker genes in vitro. Furthermore, rhPAI-1 promoted mineralized nodules formation of hPDLSCs and hPAFSCs, and we identified that other proteins, RANTES and IL-6, were highly expressed in P-CM.

CONCLUSIONS

P-CM promoted the differentiation of hPDLSCs and hPAFSCs by upregulating the expression of RANTES and IL-6, and interaction between PAI-1 and RANTES/IL-6 signaling may be involved in P-CM-induced osteogenic/cementogenic differentiation.

Functional State of Mesenchymal Stem Cells upon Exposure to Bioactive Coatings on Titanium Alloys

Bioactive coatings on implants affect osteogenic differentiation of mesenchymal stem cells (MSC). We studied the morphofunctional state of bone marrow MSC cultured on the surface of calcium phosphate coatings on titanium formed by plasma electrolytic oxidation (PEO). The biocompatible properties of the coatings manifested in the absence of the cytotoxic effect on cells. High expression of receptors (CD90, CD29, and CD106), enhanced synthesis of osteocalcin and osteopontin, and changes in surface architectonics of MSC adherent to the samples confirmed osteoinductive properties of the calcium phosphate PEO coating.

Platelet-rich plasma counteracts detrimental effect of high-glucose concentrations on mesenchymal stem cells from Bichat fat pad

Diabetic patients display increased risk of periodontitis and failure in bone augmentation procedures. Mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) represent a relevant advantage in tissue repair process and regenerative medicine. We isolated MSCs from Bichat's buccal fat pad (BFP) and measured the effects of glucose and PRP on cell number and osteogenic differentiation potential. Cells were cultured in the presence of 5.5-mM glucose (low glucose [LG]) or 25-mM glucose (high glucose [HG]). BFP-MSC number was significantly lower when cells were cultured in HG compared with those in LG. Following osteogenic differentiation procedures, calcium accumulation, alkaline phosphatase activity, and expression of osteogenic markers were significantly lower in HG compared with LG. Exposure of BFP-MSC to PRP significantly increased cell number and osteogenic differentiation potential, reaching comparable levels in LG and in HG. Thus, high-glucose concentrations impair BFP-MSC growth and osteogenic differentiation. However, these detrimental effects are largely counteracted by PRP.

Positive role of calcium phosphate ceramics regulated inflammation in the osteogenic differentiation of mesenchymal stem cells

Recently, researches have confirmed the crucial role of inflammatory response in Ca-P ceramic-induced osteogenesis, however, the underlying mechanism has not yet been fully understood. In this study, BCP and β-TCP ceramics were used as material models to investigate the effect of physicochemical properties on inflammatory response in vitro. The results showed that BCP and β-TCP could support macrophages attachment, proliferation, and spreading favorably, as well as promote gene expressions of inflammatory related cytokines (IL-1, IL-6, MCP-1, and TNF-α) and growth factors (TGF-β, FGF, PDGF, VEGF, IGF, and EGF). BCP showed a facilitating function on the gene expressions earlier than β-TCP. Further coculture experiments performed in vitro demonstrated that the CMs containing various increased cytokines for macrophages pre-culture could significantly promote MSCs osteogenic differentiation, which was confirmed by the gene expressions of osteogenic specific markers and the intracellular OCN product accumulation under the stimulation of BCP and β-TCP ceramics. Further evidence was found from the formation of mineralized nodules in BCM and TCM. In addition, this study showed a concise relationship between Ca-P ceramic induced inflammation and its osteoinductivity that the increased cytokines and growth factors from macrophages could promote MSCs osteogenic differentiation.

Umbilical cord-derived Wharton's jelly for regenerative medicine applications

BACKGROUND

The last decade has seen an explosion in the interest in using biologics for regenerative medicine applications, including umbilical cord-derived Wharton's Jelly. There is insufficient literature assessing the amount of growth factors, cytokines, hyaluronic acid, and extracellular vesicles including exosomes in these products. The present study reports the development of a novel Wharton's jelly formulation and evaluates the presence of growth factors, cytokines, hyaluronic acid, and extracellular vesicles including exosomes.

METHODS

Human umbilical cords were obtained from consenting caesarian section donors. The Wharton's jelly was then isolated from the procured umbilical cord and formulated into an injectable form. Randomly selected samples from different batches were analyzed for sterility testing and to quantify the presence of growth factors, cytokines, hyaluronic acid, and extracellular vesicles.

RESULTS

All samples passed the sterility test. Growth factors including IGFBP 1, 2, 3, 4, and 6, TGF-α, and PDGF-AA were detected. Several immunomodulatory cytokines, such as RANTES, IL-6R, and IL-16, were also detected. Pro-inflammatory cytokines MCSFR, MIP-1a; anti-inflammatory cytokines TNF-RI, TNF-RII, and IL-1RA; and homeostatic cytokines TIMP-1 and TIMP-2 were observed. Cytokines associated with wound healing, ICAM-1, G-CSF, GDF-15, and regenerative properties, GH, were also expressed. High concentrations of hyaluronic acid were observed. Particles in the extracellular vesicle size range were also detected and were enclosed by the membrane, indicative of true extracellular vesicles.

CONCLUSION

There are numerous growth factors, cytokines, hyaluronic acid, and extracellular vesicles present in the Wharton's jelly formulation analyzed. The amount of these factors in Wharton's jelly is higher compared with other biologics and may play a role in reducing inflammation and pain and augment healing of musculoskeletal injuries.

Chemokines and Bone

Chemokines are a family of small proteins, subdivided by their conserved cysteine residues and common structural features. Chemokines interact with their cognate G-protein-coupled receptors to elicit downstream signals that result in cell migration, proliferation, and survival. This review presents evidence for how the various CXC and CC subfamily chemokines influence bone hemostasis by acting on osteoclasts, osteoblasts, and progenitor cells. Also discussed are the ways in which chemokines contribute to bone loss as a result of inflammatory diseases such as rheumatoid arthritis, HIV infection, and periodontal infection. Both positive and negative effects of chemokines on bone formation and bone loss are presented. In addition, the role of chemokines in altering the bone microenvironment through effects on angiogenesis and tumor invasion is discussed. Very few therapeutic agents that influence bone formation by targeting chemokines or chemokine receptors are available, although a few are currently being evaluated.

Elevated plasma RANTES in fibrodysplasia ossificans progressiva - A novel therapeutic target?

Fibrodysplasia ossificans progressiva (FOP) is a rare hereditary disease caused by a mutation in the intracellular domain of the activin A receptor type I and is characterized by episodes (flare-ups) of progressive heterotopic endochondral ossification (HO) in the soft tissues. The mutation alone is not sufficient for the occurrence of HO since flare-ups are triggered by inflammation and activation of the innate immune system. A number of cellular and humoral mediators have been implicated in animal and in vitro models. Observations in humans support the inflammatory nature of the condition, but data on the involved mediators are variable. We hypothesize that for induction of flare-ups in patients with FOP increase in at least one of the pro-inflammatory cytokines is both essential and sufficient to trigger the entire process of the inflammatory cells influx resulting in the novel ectopic bone formation and we suggest that C-C motif ligand 5 (CCL5), a pro-inflammatory chemokine also known as Regulated on activation, normal T-cell expressed and secreted (RANTES), might be the key candidate. CCL5 is a chemoattractant for all cellular types implicated in HO and is produced by the cells of the tissue microenvironment at the sites of HO as well as by the pro-inflammatory cellular mediators. CCL5 induces ossification in cultured human pluripotent mesenchymal cells (hMSCs) and in the primary culture of monocytes from FOP patients (but not from their healthy relatives), stimulation with lipopolysaccharide induces CCL5 expression. Finally, in a pilot study we used a panel of 23 cytokines and chemokines to screen the plasma samples of three subjects: a female patient with FOP during a flare-up; a female patient with hyperostosis corticalis generalisata (van Buchem disease), another rare disease characterized by excessive bone formation at the sites where it regularly occurs that does not include inflammatory events; and a healthy woman without bone disorders. There appeared a rather clear-cut signal of a 2-fold higher level of CCL5 in the FOP patient vs. the healthy subject and the van Buchem patient. Evaluation of the hypothesis would require an international prospective study, with main motivation being the lack of a conclusive treatment as the major unmet need in FOP. A treatment targeting CCL5 receptor already exists and is used in HIV-infected patients.

Calcification biomarkers and vascular dysfunction in obesity and type 2 diabetes: influence of oral hypoglycemic agents

Vascular aging in obesity and type 2 diabetes (T2D) is associated with progressive vascular calcification, an independent predictor of morbidity and mortality. Pathways for vascular calcification modulate bone matrix deposition, thus regulating calcium deposits. We investigated the association between biomarkers of vascular calcification and vasodilator function in obesity or T2D, and whether antidiabetic therapies favorably impact those markers. Circulating levels of proteins involved in vascular calcification, such as osteopontin (OPN), osteoprotegerin (OPG), regulated on activation, normal T cell expressed and secreted (RANTES), and fetuin-A were measured in lean subjects, individuals with metabolically healthy obesity (MHO), and patients with metabolically unhealthy obesity (MUO) or T2D. Vasodilator function was assessed by infusion of ACh and sodium nitroprusside (SNP). Circulating levels of OPN were higher in the MUO/T2D group than in lean subjects (P < 0.05); OPG and RANTES were higher in MUO/T2D group than in the other groups (both P < 0.001); fetuin-A was not different between groups (P > 0.05); vasodilator responses to either ACh or SNP were impaired in both MUO/T2D and MHO compared with lean subjects (all P < 0.001). In patients with T2D who were enrolled in the intervention trial, antidiabetic treatment with glyburide, metformin, or pioglitazone resulted in a significant reduction of circulating OPG (P = 0.001), without changes in the other biomarkers and vasodilator responses (all P > 0.05). In conclusion, obese patients with MUO/T2D have elevated circulating OPN, OPG, and RANTES; in these patients, antidiabetic treatment reduces only circulating OPG. Further study is needed to better understand the mechanisms of vascular calcifications in obesity and diabetes.

Exosome-integrated titanium oxide nanotubes for targeted bone regeneration

Exosomes are extracellular nanovesicles that play an important role in cellular communication. The modulatory effects of bone morphogenetic protein 2 (BMP2) on macrophages have encouraged the functionalization of scaffolds through the integration of the exosomes from the BMP2-stimulated macrophages to avoid ectopic bone formation and reduce adverse effects. To determine the functionality of exosomal nanocarriers from macrophages after BMP2 stimulation, we isolated the exosomes from Dulbecco's modified Eagle's medium (DMEM)- or BMP2-stimulated macrophages and evaluated their effects on osteogenesis. Morphological characterization of the exosomes derived from DMEM- or BMP2-treated macrophages revealed no significant differences, and the bone marrow-derived mesenchymal stromal cells showed similar cellular uptake patterns for both exosomes. In vitro study using BMP2/macrophage-derived exosomes indicated their beneficial effects on osteogenic differentiation. To improve the bio-functionality for titanium implants, BMP2/macrophage-derived exosomes were used to modify titanium nanotube implants to favor osteogenesis. The incorporation of BMP2/macrophage-derived exosomes dramatically increased the expression of early osteoblastic differentiation markers, alkaline phosphatase (ALP) and BMP2, indicative of the pro-osteogenic role of the titanium nanotubes incorporated with BMP2/macrophage-derived exosomes. The titanium nanotubes functionalized with BMP2/macrophage-derived exosomes activated autophagy during osteogenic differentiation. In conclusion, the exosome-integrated titanium nanotube may serve as an emerging functional material for bone regeneration. STATEMENT OF SIGNIFICANCE: The clinical application of bone morphogenetic protein 2 (BMP2) is often limited by its side effects. Exosomes are naturally secreted nanosized vesicles derived from cells and play an important role in intercellular communication. The contributions of this study include (1) the demonstration of the potential regulatory role of BMP2/macrophage-derived exosomes on the osteogenic differentiation of mesenchymal stromal cells (MSCs); (2) fabrication of titanium nanotubes incorporated with exosomes; (3) new insights into the application of titanium nanotube-based materials for the safe use of BMP2.

Body Fat Percentage, Body Mass Index, Fat Mass Index and the Ageing Bone: Their Singular and Combined Roles Linked to Physical Activity and Diet

This study took a multi-analytical approach including group differences, correlations and unit-weighed directional z-score comparisons to identify the key mediators of bone health. A total of 190 participants (18⁻80 years) were categorized by body fat%, body mass index (BMI) and fat mass index (FMI) to examine the effect of differing obesity criteria on bone characteristics. A subset of 50 healthy-eating middle-to-older aged adults (44⁻80 years) was randomly selected to examine any added impact of lifestyle and inflammatory profiles. Diet was assessed using a 3-day food diary, bone mineral density (BMD) and content (BMC) by dual energy x-ray absorptiometry in the lumbar, thoracic, (upper and lower) appendicular and pelvic areas. Physical activity was assessed using the Baecke questionnaire, and endocrine profiling was assessed using multiplex luminometry. Obesity, classed via BMI, positively affected 20 out of 22 BMC- and BMD-related outcome measures, whereas FMI was associated with 14 outcome measures and adiposity only modulated nine out of 22 BMC- and BMD-related outcome measures. Whilst bivariate correlations only linked vitamin A and relative protein intake with BMD, the Z-score composite summary presented a significantly different overall dietary quality between healthy and osteopenic individuals. In addition, bivariate correlations from the subset revealed daily energy intake, sport-based physical activity and BMI positive mediators of seven out of 10 BMD sites with age and body fat% shown to be negative mediators of bone characteristics. In conclusion, whilst BMI is a good indicator of bone characteristics, high body fat% should also be the focus of osteoporosis risk with ageing. Interestingly, high BMI in conjunction with moderate to vigorous activity supplemented with an optimal diet (quality and quantity) are identified as positive modulators of bone heath.

Angiopoietin-2 promotes osteogenic differentiation of thoracic ligamentum flavum cells via modulating the Notch signaling pathway

Thoracic ossification of the ligamentum flavum (TOLF) is heterotopic ossification of spinal ligaments, which may cause serious thoracic spinal canal stenosis and myelopathy. However, the underlying etiology remains inadequately understood. In this study, the ossification patterns of TOLF were analyzed by micro-computer tomography (micro-CT). The expression profile of genes associated with angiogenesis was analyzed in thoracic ligamentum flavum cells at sites of different patterns of ossification using RNA sequencing. Significant differences in the expression profile of several genes were identified from Gene Ontology (GO) analysis. Angiopoietin-2 (ANGPT2) was significantly up-regulated in primary thoracic ligamentum flavum cells during osteogenic differentiation. To address the effect of ANGPT2 on Notch signaling and osteogenesis, ANGPT2 stimulation increased the expression of Notch2 and osteogenic markers of primary thoracic ligamentum flavum cells of immature ossification, while inhibition of ANGPT2 exhibited opposite effect on Notch pathway and osteogenesis of cells of mature ossification. These findings provide the first evidence for positive regulation of ANGPT2 on osteogenic differentiation in human thoracic ligamentum flavum cells via modulating the Notch signaling pathway.

OVO homologue-like 1 promotes osteoblast differentiation through BMP2 expression

OVO homologue-like 1 (OVOL1) encodes a C2H2 zinc finger protein and is an evolutionarily conserved gene in mammals. The OVOL1 expression is required for development. However, the function of OVOL1 in bone metabolism remains unreported. Here, we show for the first time the role of OVOL1 in osteoblast differentiation. To determine the role of OVOL1 in osteogenic differentiation, we analyzed OVOL1 expression in the preosteoblastic cell line. OVOL1 messenger RNA expression was induced during osteoblast differentiation. In addition, OVOL1 overexpression enhanced the expression of osteogenic genes including bone morphogenetic protein 2 (BMP2), the inhibitor of DNA binding 1 (Id1), distal-less homeobox 5 (Dlx5), runt-related transcription factor 2 (Runx2), osteocalcin (OC), and alkaline phosphatase (ALP). Moreover, mineralization of the extracellular matrix was increased by OVOL1 overexpression in MC3T3-E1 cells. Furthermore, knockdown of the OVOL1 experiment demonstrated that OVOL1 is required for osteoblast differentiation. Collectively, these results suggest that OVOL1 function as an important regulator of osteoblast differentiation by inducing BMP2 expression in MC3T3-E1 cells.

Calcium phosphate altered the cytokine secretion of macrophages and influenced the homing of mesenchymal stem cells

Immune cells such as macrophages play an important role in tissue regeneration. In this study, an in vivo mouse intramuscular implantation model was applied to demonstrate the gradual infiltration of macrophages, followed by homing of mesenchymal stem cells (MSCs) during the early phase of biphasic calcium phosphate (BCP)-induced ectopic bone formation. Then, a novel real-time cell analysis (RTCA) system was used to continuously monitor cell migration in vitro, suggesting the positive roles of BCP-mediated macrophage secretion in MSC recruitment. A Proteome Profiler cytokine array was also applied to investigate the BCP-stimulated secretion pattern of macrophages by simultaneously screening 111 cytokines, indicating that Raw 264.7 macrophages released a pronounced amount of chemokines (CCL2, 3, 4, 5 and CXCL2, 10, 16) and non-chemokine molecules (OPN, VEGF, CD14, Cystatin C and PAI-1), which are involved in cell homing and bone regeneration. Among them, osteoinductive BCP ceramics significantly promoted the secretion of CCL2, 3, 4 and Cystatin C in macrophages, which was consistent with the up-regulated expression of chemokine genes (Ccl2, 3, 4). Considering their previously-reported chemotactic functions, the effects of CCL2/MCP-1 and CCL3/MIP-1α on MSC recruitment were further evaluated by the RTCA system. It was found that exogenous CCL2/MCP-1 and CCL3/MIP-1α dramatically accelerated MSC migration, while their neutralizing antibodies reduced MSC motility. Moreover, BCP-mediated macrophage secretion up-regulated the gene expression of chemokine receptors (Ccr1 and Ccr2) in MSCs, but the blockage of CCR1 and CCR2 exerted inhibitory effects on MSC chemotaxis. RTCA results showed that compared to CCL3/CCR1, the CCL2/CCR2 axis might exert a predominant chemotactic effect for MSC recruitment. These findings indicated that osteoinductive BCP ceramics might regulate macrophage secretion via an ERK signaling pathway, and the increased release of chemokines in macrophages would accelerate MSC homing to facilitate bone formation. These findings might deepen our understanding of biomaterial-mediated immune response and help to design orthopedic implants with desired immunomodulatory abilities to recruit host stem cells endogenously for bone regeneration.

Adaptive Regulation of Osteopontin Production by Dendritic Cells Through the Bidirectional Interaction With Mesenchymal Stromal Cells

Mesenchymal stromal cells (MSCs) exert immunosuppressive effects on immune cells including dendritic cells (DCs). However, many details of the bidirectional interaction of MSCs with DCs are still unsolved and information on key molecules by which DCs can modulate MSC functions is limited. Here, we report that osteopontin (OPN), a cytokine involved in homeostatic and pathophysiologic responses, is constitutively expressed by DCs and regulated in the DC/MSC cocultures depending on the activation state of MSCs. Resting MSCs promoted OPN production, whereas the production of OPN was suppressed when MSCs were activated by proinflammatory cytokines (i.e., TNF-α, IL-6, and IL-1β). OPN induction required cell-to-cell contact, mediated at least in part, by β1 integrin (CD29). Conversely, activated MSCs inhibited the release of OPN via the production of soluble factors with a major role played by Prostaglandin E₂ (PGE₂). Accordingly, pretreatment with indomethacin significantly abrogated the MSC-mediated suppression of OPN while the direct addition of exogenous PGE₂ inhibited OPN production by DCs. Furthermore, DC-conditioned medium promoted osteogenic differentiation of MSCs with a concomitant inhibition of adipogenesis. These effects were paralleled by the repression of the adipogenic markers PPARγ, adiponectin, and FABP4, and induction of the osteogenic markers alkaline phosphatase, RUNX2, and of the bone-anabolic chemokine CCL5. Notably, blocking OPN activity with RGD peptides or with an antibody against CD29, one of the OPN receptors, prevented the effects of DC-conditioned medium on MSC differentiation and CCL5 induction. Because MSCs have a key role in maintenance of bone marrow (BM) hematopoietic stem cell niche through reciprocal regulation with immune cells, we investigated the possible MSC/DC interaction in human BM by immunohistochemistry. Although DCs (CD1c⁺) are a small percentage of BM cells, we demonstrated colocalization of CD271⁺ MSCs with CD1c⁺ DCs in normal and myelodysplastic BM. OPN reactivity was observed in occasional CD1c⁺ cells in the proximity of CD271⁺ MSCs. Altogether, these results candidate OPN as a signal modulated by MSCs according to their activation status and involved in DC regulation of MSC differentiation.

Electronic Cigarette Smoke Impairs Normal Mesenchymal Stem Cell Differentiation

Electronic cigarettes (e-cigarettes) are promoted as low-risk alternatives to combustible cigarettes. However, the effects of chronic inhalation of potential toxicants emitted by ecigarettes remain largely unexamined. It is conceivable that smoking-induced chronic diseases result in cellular injury, in the absence of effective repair by stem cells. This study evaluates the effect of cigarette and e-cigarette aerosol extracts on the survival and differentiation of bone marrow-derived mesenchymal stem cells (MSCs). MSC growth and osteogenic differentiation were examined after exposure to smoke extracts. Data revealed detrimental effects of both cigarette and e-cigarette extracts on MSC morphology and growth. Levels and activity of alkaline phosphatase, an osteogenic marker, decreased and induction of osteoblastic differentiation was impaired. Both smoke extracts prevented osteogenic differentiation from progressing, evident by decreased expression of terminal osteogenic markers and mineralization. Elevated levels of reactive oxygen species (ROS) were detected in cells exposed to smoke extracts. Moreover, decreased differentiation potential was concomitant with severe down-regulation of Connexin 43 expression, leading to the loss of gap junction-mediated communication, which together with elevated ROS levels, could explain decreased proliferation and loss of differentiation potential. Hence, e-cigarettes present similar risk as combustible cigarettes with respect to tissue repair impairment.

CCL2, CCL5, and IGF-1 participate in the immunomodulation of osteogenesis during M1/M2 transition in vitro

The modulation of macrophage phenotype from pro-inflammatory (M1) to tissue healing (M2) via exogenous addition of interleukin-4 (IL-4) facilitates osteogenesis; however, the molecular mediators underlying this phenomenon remain unknown. This study characterizes the IL-4-dependent paracrine crosstalk between macrophages and osteoprogenitors and its effect on osteogenesis in vitro. Primary murine M1 were co-cultured with MC3T3 cells (M1-MC3T3) in both transwell plates and direct co-cultures. To modulate M1 to M2, M1-MC3T3 were treated with IL-4 (20 ng/mL) at day 3 after seeding (M1 + IL-4-MC3T3). Selected molecular targets were assessed at days 3 and 6 after seeding at protein and mRNA levels. Mineralization was assessed at day 21. Transwell M1 + IL-4-MC3T3 significantly enhanced the secretion of CCL2/MCP-1, IGF-1 and to a lesser degree, CCL5/RANTES at day 6. At day 3, alkaline phosphatase (Alpl) was upregulated in direct M1-MC3T3. At day 6, Smurf2 and Insulin growth factor-1 (IGF-1) were downregulated and upregulated, respectively, in direct M1 + IL-4-MC3T3. Finally, M1 + IL-4-MC3T3 increased bone matrix mineralization compared with MC3T3 cells in transwell, but this was significantly less than M1-MC3T3. Taken together, macrophage subtypes enhanced the osteogenesis in transwell setting and the transition from M1 to M2 was associated with an increase in bone anabolic factors CCL2/MCP-1, CCL5/RANTES and IGF-1 in vitro. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3069-3076, 2017.

Angiopoietin-2 Enhances Osteogenic Differentiation of Bone Marrow Stem Cells

Our previous studies revealed that co-transplantation of bone marrow stem cells (BMSCs) and adipose-derived stem cells (ADSCs) can enhance bone regeneration and angiogenesis. However, it is unclear which genes are involved in the regulation of osteogenesis and/or angiogenesis during the co-culturing of BMSCs and ADSCs. The expression patterns of genes associated with osteogenesis and/or angiogenesis were analyzed in osteogenesis-induced BMSCs and ADSCs using an oligonucleotide microarray. Significant difference in the expression patterns of several genes were identified from hierarchical clustering and analyzed on co-cultured BMSCs and ADSCs. Angiopoietin-2 (ANGPT2) and activin receptor-like kinase-1 were significantly down-regulated in co-culture than culture of either BMSCs or ADSCs, while fibroblast growth factor-9 was significantly up-regulated in co-culture. The effect of ANGPT2 in osteogenesis-induced BMSCs was validated using recombinant protein and siRNA of ANGPT2. Treatment of the ANGPT2 protein significantly increased the expressions of osteogenic makers and the intensity of Alizarin red-S staining in BMSCs. Down-regulation of ANGPT2 significantly decreased the expression of osteogenic makers. The treatment of ANGPT2 protein to BMSCs induced significantly increased tube formation in Transwell-co-cultured human umbilical vein endothelial cells (HUVECs) compared with untreated control. ANGPT2 siRNA transfection showed the opposite effects. These results suggest that the treatment of ANGPT2 in BMSCs increase osteogenesis and angiogenesis in vitro, and that the enhancement of osteogenesis and angiogenesis in the co-cultured BMSCs and ADSCs seems to be mediated by a mechanism that makes the activation of ANGPT2 unnecessary. These observations provide the first evidence for positive regulation of osteogenesis by ANGPT2 in vitro. J. Cell. Biochem. 118: 2896-2908, 2017. © 2017 Wiley Periodicals, Inc.

Platelet-functionalized three-dimensional poly-ε-caprolactone fibrous scaffold prepared using centrifugal spinning for delivery of growth factors

Bone and cartilage are tissues of a three-dimensional (3D) nature. Therefore, scaffolds for their regeneration should support cell infiltration and growth in all 3 dimensions. To fulfill such a requirement, the materials should possess large, open pores. Centrifugal spinning is a simple method for producing 3D fibrous scaffolds with large and interconnected pores. However, the process of bone regeneration is rather complex and requires additional stimulation by active molecules. In the current study, we introduced a simple composite scaffold based on platelet adhesion to poly-ε-caprolactone 3D fibers. Platelets were used as a natural source of growth factors and cytokines active in the tissue repair process. By immobilization in the fibrous scaffolds, their bioavailability was prolonged. The biological evaluation of the proposed system in the MG-63 model showed improved metabolic activity, proliferation and alkaline phosphatase activity in comparison to nonfunctionalized fibrous scaffold. In addition, the response of cells was dose dependent with improved biocompatibility with increasing platelet concentration. The results demonstrated the suitability of the system for bone tissue.

SV40 Infection of Mesenchymal Stromal Cells From Wharton's Jelly Drives the Production of Inflammatory and Tumoral Mediators

The Mesenchymal Stromal Cells from umbilical cord Wharton's jelly (WJSCs) are a source of cells with high potentiality for the treatment of human immunological disorders. Footprints of the oncogenic viruses Simian Virus 40 (SV40) and JC Virus (JCPyV) have been recently detected in human WJSCs specimens. The aim of this study is to evaluate if WJSCs can be efficiently infected by these Polyomaviruses and if they can potentially exert tumoral activity. Cell culture experiments indicated that WJSCs could sustain both SV40 and JCPyV infections. A transient and lytic replication was observed for JCPyV, while SV40 persistently infected WJSCs over a long period of time, releasing a viral progeny at low titer without evident cytopathic effect (CPE). Considering the association between SV40 and human tumors and the reported ability of the oncogenic viruses to drive the host innate immune response to cell transformation, the expression profile of a large panel of immune mediators was evaluated in supernatants by the Bioplex platform. RANTES, IL-3, MIG, and IL-12p40, involved in chronic inflammation, cells differentiation, and transformation, were constantly measured at high concentration comparing to control. These findings represent a new aspect of SV40 biological activity in the humans, highlighting its interaction with specific host cellular pathways. In view of these results, it seems to be increasingly urgent to consider Polyomaviruses in the management of WJSCs for their safely use as promising therapeutic source. J. Cell. Physiol. 232: 3060-3066, 2017. © 2016 Wiley Periodicals, Inc.

Transplantation of human Wharton's jelly-derived mesenchymal stem cells highly expressing TGFβ receptors in a rabbit model of disc degeneration

Introduction

Mesenchymal stem cells (MSCs) are widely considered to hold promise for the treatment of intervertebral disc (IVD) degeneration. However, variation in the therapeutic efficacy of MSCs is a major problem and the derivation of MSCs for use in IVD regeneration has not been optimized. Additionally, no data are available on the efficacy of Wharton’s Jelly-derived MSC (WJ-MSC) transplantation in an animal model of IVD degeneration.

Methods

This study evaluated the effectiveness of a cross-linked hyaluronic acid (XHA) scaffold loaded with human WJ-MSCs, according to their expression levels of transforming growth factor-β receptor I/activin-like kinase receptor 5 (TβRI/ALK5) and TβRII, for IVD regeneration in a rabbit model. We compared the degree of IVD regeneration between rabbits transplanted with a XHA scaffold loaded with WJ-MSCs highly and lowly expressing TβRI/ALK5 and TβRII (MSC-highTR and MSC-lowTR, respectively) using magnetic resonance imaging (MRI) and histological analysis.

Results

At 12 weeks after transplantation, T2-weighted MRI analysis showed significant restoration of the disc water content in rabbits treated with a MSC-highTR-loaded XHA scaffold in comparison to rabbits treated with the scaffold alone or a MSC-lowTR-loaded XHA scaffold. In addition, morphological and histological analyses revealed that IVD regeneration was highest in rabbits transplanted with a MSC-highTR-loaded XHA scaffold.

Conclusion

Taken together, our results suggest that a MSC-highTR-loaded XHA scaffold supports IVD regeneration more effectively than a MSC-lowTR-loaded XHA scaffold. This study supports the potential clinical use of MSC-highTR-loaded XHA scaffolds to halt IVD degeneration or to enhance IVD regeneration.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0183-1) contains supplementary material, which is available to authorized users.

Characteristics of Human Turbinate-Derived Mesenchymal Stem Cells Are Not Affected by Allergic Condition of Donor

The characteristics of mesenchymal stem cells (MSCs) derived from human turbinates (hTMSCs) have not been investigated in allergic rhinitis. We evaluated the influence of allergic state of the donor on the characteristics, proliferation, and differentiation potential of hTMSCs, compared with hTMSCs derived from non-allergic patients. hTMSCs were isolated from five non-allergic and five allergic patients. The expression of toll-like receptors (TLRs) in hTMSCs was measured by FACS, and cell proliferation was measured using a cell counting kit. Cytokine secretion was analyzed using multiplex immunoassays. The osteogenic, chondrogenic, and adipogenic differentiation potentials of hTMSCs were evaluated by histology and gene expression analysis. In allergic patients, FACS analysis showed that TLR3 and TLR4 were more highly expressed on the surface of hTMSCs than TLR2 and TLR5. The proliferation of hTMSCs was not influenced by the presence of TLR priming. The expression of IL-6, IL-8, IL-12, IP-10, and RANTES was upregulated after the TLR4 priming. The differentiation potential of hTMSCs was not influenced by TLR priming. These characteristics of hTMSCs were similar to those of hTMSCs from non-allergic patients. We conclude that the allergic condition of the donor does not influence TLR expression, proliferation, or immunomodulatory potential of hTMSCs.