A national registry-based study of ethnic differences in people with multiple sclerosis in Iran.

OBJECTIVE: The relationship between MS and ethnicity has been understudied in the Middle East compared to the United States and Europe. As Iran as the highest prevalence of MS in the Middle East, we decided to investigate the demographic and clinical differences in people with MS (pwMS) from major ethnicities Iran. METHODS: In a cross-sectional study using data from National Multiple Sclerosis Registry in Iran. PwMS from six provinces were chosen and interviewed for determining their ethnicity. Persians (Fars), Kurds, Lurs, Azeris and Arabs with a clear ethnic background were included. Recorded data from the registry was used to compare the demographic and clinical features. RESULTS: A total of 4015 pwMS (74.2% female) were included in the study with an average age of 36.76 ± 9.68 years. Persians and Kurds had the highest percentage of pwMS in youngest and oldest age groups, respectively, with 2.9% and 5.7% (p<0.01). The highest average age of onset was seen in Persians (29.47 ± 8.89) and the lowest observed in Mazandaranis (26.82 ± 7.68, p<0.01). Azeris and Kurds had the highest proportions of pwMS diagnosed <18 and >55, at rates of 12% and 1.6%, respectively (p<0.01). There were statistically significant differences in distribution of phenotypes (p<0.01) and time to progression to secondary progressive MS (p<0.01) such that Persians had the highest rate of clinically isolated syndrome (CIS) at 19.3% and Arabs had highest rates of relapsing-remitting MS (86.2%) and secondary progressive MS (16.4%). Lurs, Azeris and Mazandaranis had significantly more patients progressing to secondary-progressive MS <5 years from diagnosis (p<0.01). There was a significant difference in number of relapses between the ethnicities (p<0.01) with Lurs having the highest proportion of participants reporting >4 relapses with 23.0% and Azeris having the highest percentage of pwMS reporting no relapse (53.0%). Kurds had the highest Expanded Disability Status Scale (EDSS) average at 2.93 ± 1.99 and Lurs had the lowest with 1.28 ± 1.25 (p<0.01). The differences in prevalence of positive family history for the whole cohort between ethnicities were significant (P=0.02), ranging from 12.8% in Kurds to 19.6% in Persians. CONCLUSION: We found Persians to have higher rates of pediatric MS and higher rates of CIS. Kurds and Lurs had higher and lower EDSS scores, respectively. Lurs and Persian had higher annual relapse rates. We also found lower rates of SPMS among Arabs and earlier progression to SPMS in Lurs, Azeris and Mazandaranis. Such differences highlight the importance of the potential role of ethnicities in diagnosis and prognosis of MS, especially considering their observation within the geographical limits of a single country.

Iranian specialists' approach to surgery in patients with multiple sclerosis.

Background: Data on perioperative risk stratification in patients with multiple sclerosis (MS) are limited. In this regard, the present study was conducted to investigate Iranian specialists' approach to surgical counseling for patients with MS (PwMS). Methods: 21 MS specialists were asked about 11 case scenarios with different MS disease statuses, disease-modifying therapies (DMTs), and urgency of the operation. The reasons for refusing surgery or factors that have to be considered before surgery were studied. Results: Overall, Fleiss Kappa was estimated to be 0.091 [95% confidence interval (CI): 0.090-0.093, P < 0.001] indicating a very poor level of agreement among responders. Conclusion: PwMS face surgery for various reasons. Risk assessment of surgery, the effect of various drugs such as anesthetics and DMT on patients, as well as many other aspects of MS are issues challenging the practitioners. Clarifying the various dimensions of these issues requires further research.

Efficacy of Tibial Nerve Stimulation in Neurogenic Lower Urinary Tract Dysfunction Among Patients with Multiple Sclerosis: A Systematic Review and Meta-analysis.

OBJECTIVE: This study was performed to systematically review the current literature on the effects of transcutaneous tibial nerve stimulation and percutaneous tibial nerve stimulation on multiple sclerosis-induced neurogenic lower urinary tract dysfunction. MATERIALS AND METHODS: Medical databases including PubMed, Scopus, Embase, and Web of Science were systematically searched from inception to September 2022. Metaanalysis was carried out using the comprehensive meta-analysis tool. RESULTS: Our inclusion criteria were met by 12 studies evaluating the effects of percutaneous tibial nerve stimulation/transcutaneous tibial nerve stimulation on multiple sclerosis-induced neurogenic lower urinary tract dysfunction. Comparing the postintervention results to the baseline showed that the rate of frequency was decreased in both percutaneous tibial nerve stimulation and transcutaneous tibial nerve stimulation groups after intervention. The overall mean change of tibial nerve stimulation on frequency was -2.623 (95% CI: -3.58, -1.66; P < .001, I 2 : 87.04) among 6 eligible studies. The post-void residual was decreased after treatment in both methods of tibial nerve stimulation, with an overall mean difference of -31.13 mL (95% CI: -50.62, -11.63; P=.002, I 2 : 71.81). The other urinary parameters, including urgency (mean difference: -4.69; 95% CI: -7.64, -1.74; P < .001, I 2 : 92.16), maximum cystometric capacity (mean difference: 70.95; 95% CI: 44.69, 97.21; P < .001, I 2 : 89.04), and nocturia (mean difference: -1.41; 95% CI: -2.22, 0.60; P < .001, I 2 : 95.15), were improved after intervention, too. However, the results of subgroup analysis showed no effect of transcutaneous tibial nerve stimulation on urinary incontinence (mean difference: -2.00; 95% CI: -4.06, 0.06; P=.057, I 2 : 95.22) and nocturia (mean difference: -0.39; 95% CI: -1.15, 0.37; P=.315, I 2 : 84.01). In terms of mean voided volume, the evidence was related to only percutaneous tibial nerve stimulation with a mean change of 75.01 mL (95% CI: -39.40, 110.61; P < .001, I 2 : 85.04). CONCLUSION: Although the current literature suggests that tibial nerve electrostimulation might be an effective method for treating neurogenic lower urinary tract dysfunction, the evidence base is poor and derived from small, mostly nonrandomized trials with a high risk of bias and confounding.

Higher ratios of chondrocyte to mesenchymal stem cells elevate the therapeutic effects of extracellular vesicles harvested from chondrocyte/mesenchymal stem cell co-culture on osteoarthritis in a rat model.

Extracellular vesicles (EVs) may have a key therapeutic role and offer an innovative treatment for osteoarthritis (OA). Studies have shown that ratio of MSC/chondrocyte could affect their therapeutic outcomes. Here, we investigate the chondrogenic potential and therapeutic effect of EVs derived from MSCs and chondrocytes in the naïve, chondrogenically primed, and co-culture states to treat OA. EVs are isolated from naïve MSCs (M-EV), chondrogenically primed MSCs (cpM-EV), chondrocytes (C-EV), and co-cultures of chondrocytes plus MSCs at ratios of 1:1 (C/M-EV), 2:1 (2C/M-EV), and 4:1 (4C/M-EV). We characterized the isolated EVs in terms of surface markers, morphology, size, and zeta potential, and evaluated their chondrogenic potential in vitro by qRT-PCR and histological analyses. Next, these EVs were intra-articularly injected into osteoarthritic cartilage of a rat model and assessed by radiography, gait parameters, and histological and immunohistochemical analyses. EVs obtained from chondrocytes co-cultured with MSCs resulted in improved matrix production and functional differentiation. Our research showed that close proximity between the two cell types was essential for this response, and improved chondrogenesis and matrix formation were the outcomes of this interaction in vitro. Furthermore, in the in vivo rat OA model induced by a monoiodoacetate (MIA), we observed recovery from OA by increasing ratio of the C/M-derived EV group compared to the other groups. Our findings show that the increasing chondrocyte ratio to MSC leads to high chondrogenic induction and the therapeutic effect of harvested EVs for cartilage repair.

Effective role of Curcumin on expression regulation of EZH2 histone methyltransferase as a dynamic epigenetic factor in osteogenic differentiation of human mesenchymal stem cells.

BACKGROUND: Efficient differentiation of mesenchymal stem cells (MSCs) into a desired cell lineage remains challenging in cell-based therapy and regenerative medicine. Numerous efforts have been made to efficiently promote differentiation of MSCs into osteoblast lineage. Accordingly, epigenetic signatures emerge as a key conductor of cell differentiation. Among them, Enhancer of Zeste Homolog 2 (EZH2), a histone methyltransferase appears to suppress osteogenesis. Curcumin is an osteoinductive natural polyphenol compound which supposedly modulates epigenetic mechanisms. Hence, the current study aims to address the role of the EZH2 epigenetic factor in osteogenic activity of MSCs after Curcumin treatment. METHODS: The effect of Curcumin on viability and osteogenic differentiation was evaluated at different time points in vitro. The expression level of EZH2 was assessed using quantitative real-time polymerase chain reaction (qRT-PCR) after 14 and 21 days. RESULTS: MTT results showed no cytotoxic effects at concentrations of 10 and 15 µM of Curcumin and cells survived up to 70 % at all time-points. qRT-PCR results demonstrated that Curcumin significantly enhanced the expression levels of osteogenic markers that included Runx2, Osterix, Collagen type I, Osteopontin and Osteocalcin at day 21. CONCLUSIONS: Interestingly, we observed that the expression level of the EZH2 gene was downregulated in the presence of Curcumin compared to the control group during osteogenesis. This study confirmed that Curcumin acts as an epigenetic switch to regulate osteoblast differentiation specifically through the EZH2 suppression.

Co-aggregation of MSC/chondrocyte in a dynamic 3D culture elevates the therapeutic effect of secreted extracellular vesicles on osteoarthritis in a rat model.

Extracellular vesicles (EVs) have therapeutic effects on osteoarthritis (OA). Some recent strategies could elevate EV's therapeutic properties including cell aggregation, co-culture, and 3D culture. It seems that a combination of these strategies could augment EV production and therapeutic potential. The current study aims to evaluate the quantity of EV yield and the therapeutic effect of EVs harvested from rabbit mesenchymal stem cells (MSCs) aggregates, chondrocyte aggregates, and their co-aggregates in a dynamic 3D culture in a rat osteoarthritis model. MSC and chondrocytes were aggregated and co-aggregated by spinner flasks, and their conditioned medium was collected. EVs were isolated by size exclusion chromatography and characterized in terms of size, morphology and surface markers. The chondrogenic potential of the MSC-ag, Cho-ag and Co-ag EVs on MSC micromass differentiation in chondrogenic media were assessed by qRT-PCR, histological and immunohistochemical analysis. 50 µg of MSC-ag-EVs, Cho-ag-EVs and Co-ag-EVs was injected intra-articularly per knee of OA models established by monoiodoacetate in rats. After 8 weeks follow up, the knee joints were harvested and analyzed by radiographic, histological and immunohistochemical features. MSC/chondrocyte co-aggregation in comparison to MSC or chondrocyte aggregation could increase EV yield during dynamic 3D culture by spinner flasks. Although MSC-ag-, Cho-ag- and Co-ag-derived EVs could induce chondrogenesis similar to transforming growth factor-beta during in vitro study, Co-ag-EV could more effectively prevent OA progression than MSC-ag- and Cho-ag-EVs. Our study demonstrated that EVs harvested from the co-aggregation of MSCs and chondrocytes could be considered as a new therapeutic potential for OA treatment.

The Use of Trichostatin A during Pluripotent Stem Cell Generation Does Not Affect MHC Expression Level.

Pluripotent stem cells (PSCs) are considered as a potent tool for use in regenerative medicine. Highly efficient generation of PSCs through chromatin modulators such as trichostatin A (TSA) might change their MHC molecule expression profile. The efficiency of PSC generation and their immunogenicity is major obstacles for clinical use. Hence, we aim to investigate whether the use of TSA during PSC generation affects MHC expression level. Three PSC lines were generated by iPSCs, NT-ESCs, and IVF-ESCs' reprogramming methods from B6D2F1 mouse embryonic fibroblast cells. Established PSC lines were characterized by alkaline phosphatase assay (ALP) and immunocytochemistry. Their chromosome fidelity was checked by karyotyping. The expression level of pluripotent genes (oct4, nanog, sox2, klf4), HDACs (hdac1, hdac2, and hdac3), and immune-related genes (including Qa-1, Qa-2, H2kb, H2kd, H2db, H2db, CIITA, H2-IE-ßb, H2-IE-ßd) in iPSC and ESC lines were assessed by real-time PCR analysis. The presence of MHC molecules on the surface of pluripotent stem cells was also checked by flow cytometry technique. Significant increase of pluripotency markers, oct4, nanog, sox2, and klf4, was observed in 100 nM TSA-treated samples. 100 nM TSA induced significant upregulation of H2db in generated iPSCs. H2-IE-ßd was remarkably downregulated in 50 and 100 nM TSA-treated iPSC lines. The expression level of other immune-related genes was not greatly affected by TSA in iPSC and NT-ESC lines. It is concluded that the use of short-term and low concentration of TSA during reprogramming in PSC generation procedure significantly increases PSC generation efficiency, but do not affect the MHC expression in established cell lines, which is in the benefit of cell transplantation in regenerative medicine.

Targeted mesenchymal stem cell therapy equipped with a cell-tissue nanomatchmaker attenuates osteoarthritis progression.

Mesenchymal stem cells (MSCs) are at the forefront of research for a wide range of diseases, including osteoarthritis (OA). Despite having attracted the attention of orthopedists, current MSC therapy techniques are limited by poor MSC implantation in tissue defects and lack of lateral tissue integration, which has restricted the efficacy of cell therapy to alleviate OA symptoms only. Here, we developed targeted MSC therapy for OA cartilage using a cell-tissue matchmaking nanoconstruct (C-TMN). C-TMN, as an MSC vehicle, consists of a central iron oxide nanoparticle armed with two types of antibodies, one directed at the MSC surface and the other against articular cartilage. We treated rat OA articular cartilage with intra-articular injections of C-TMN with and without exogenous MSCs. We observed substantial improvements in both symptomatic and radiographic OA caused by C-TMN, which was independent of exogenous MSCs. This new approach could predict a promising future for OA management.

Mesenchymal Stem Cell Therapy for Osteoarthritis: Practice and Possible Promises.

Osteoarthritis (OA) is a common progressively degenerative joint disease that affects more than 300 million people worldwide. OA is manifested by articular cartilage degradation, chronic pain, deformity, functional disability, and decreased quality of life. A real challenge in OA management is the lack of an effective cure because exiting therapeutics often provide symptom control rather than disease modification; therefore, they fail to prevent disease progression. The inadequate treatments for OA management have encouraged researchers to study mesenchymal stem cells (MSCs) as an investigational treatment for OA. MSCs are a promising tool for OA because of their availability; expand cultivation and multi-lineage differentiation capacity as well as well-documented paracrine function have made MSCs a promising tool in this field. Accordingly, MSCs application has been successfully utilized in a broad range of pre-clinical OA animal models as well as clinical studies with the aim of cartilage repair which had not previously been achieved using classical treatments. Here, the brief scientific review of MSC role in the control of OA as well as the proposed mechanisms are discussed. We provide an insight into the last 10 years' studies conducted on preclinical and clinical OA treatment as well as future opportunities in OA management strategies employing MSCs.

Higher Chondrogenic Potential of Extracellular Vesicles Derived from Mesenchymal Stem Cells Compared to Chondrocytes-EVs In Vitro.

The inability of cartilage to self-repair necessitates an effective therapeutic approach to restore damaged tissues. Extracellular vesicles (EVs) are attractive options because of their roles in cellular communication and tissue repair where they regulate the cellular processes of proliferation, differentiation, and recruitment. However, it is a challenge to determine the relevant cell sources for isolation of EVs with high chondrogenic potential. The current study aims to evaluate the chondrogenic potential of EVs derived from chondrocytes (Cho-EV) and mesenchymal stem cells (MSC-EV). The EVs were separately isolated from conditioned media of both rabbit bone marrow MSCs and chondrocyte cultures. The isolated vesicles were assessed in terms of size, morphology, and surface marker expression. The chondrogenic potential of MSCs in the presence of different concentrations of EVs (50, 100, and 150 µg/ml) was evaluated during 21 days, and chondrogenic surface marker expressions were checked by qRT-PCR and histologic assays. The extracted vesicles had a spherical morphology and a size of 44.25 ± 8.89 nm for Cho-EVs and 112.1 ± 10.10 nm for MSC-EVs. Both groups expressed the EV-specific surface markers CD9 and CD81. Higher expression of chondrogenic specified markers, especially collagen type II (COL II), and secretion of glycosaminoglycans (GAGs) and proteoglycans were observed in MSCs treated with 50 and 100 µg/ml MSC-EVs compared to the Cho-EVs. The results from the use of EVs, particularly MSC-EVs, with high chondrogenic ability will provide a basis for developing therapeutic agents for cartilage repair.

Engineered-extracellular vesicles as an optimistic tool for microRNA delivery for osteoarthritis treatment.

Worldwide, osteoarthritis (OA) is one of the most common chronic diseases. In OA, profiling gene expression changes occur and cartilage tissue homeostasis is lost. Suggestions for OA treatment include regulation of gene expressions via the use of microRNAs (miRNAs). However, problems exist with the use of miRNAs, the most important of which is the delivery of sufficient amounts of effective miRNAs to save cartilage tissue. The engineering of extracellular vesicles (EVs) with the use of advanced techniques would be an efficient OA treatment. Therefore, we discuss the importance of miRNAs in terms of cartilage tissue regeneration and review recent advances in production of enriched EVs and miRNA delivery by EVs for future clinical applications.

Epidrugs: novel epigenetic regulators that open a new window for targeting osteoblast differentiation.

Efficient osteogenic differentiation of mesenchymal stem cells (MSCs) is a critical step in the treatment of bone defects and skeletal disorders, which present challenges for cell-based therapy and regenerative medicine. Thus, it is necessary to understand the regulatory agents involved in osteogenesis. Epigenetic mechanisms are considered to be the primary mediators that regulate gene expression during MSC differentiation. In recent years, epigenetic enzyme inhibitors have been used as epidrugs in cancer therapy. A number of studies mentioned the role of epigenetic inhibitors in the regulation of gene expression patterns related to osteogenic differentiation. This review attempts to provide an overview of the key regulatory agents of osteogenesis: transcription factors, signaling pathways, and, especially, epigenetic mechanisms. In addition, we propose to introduce epigenetic enzyme inhibitors (epidrugs) and their applications as future therapeutic approaches for bone defect regeneration.

Upregulation of Toll-like receptor 4 through anti-miR-Let-7a enhances blastocyst attachment to endometrial cells in mice.

Despite encouraging advances in fertility technology, the success rate of an ongoing pregnancy is relatively low and predominantly associated with implantation failure. Inflammatory responses are beneficial in the fetomaternal interface and supposedly accelerate the chances for successful implantation. The current study aims to determine the effect of Toll-like receptor 4 (TLR4) overexpression in mouse blastocysts via Let-7a downregulation using intracytoplasmic sperm injection-sperm-mediated gene transfer on embryo attachment rate. The pLenti-III-GFP-miR-Off-Let-7a vector was transmitted to oocytes derived via in vitro maturation (IVM) and in vivo oocytes by using NaOH-treated spermatozoa. Let-7a and TLR4 expression levels were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR), immunocytochemistry, and western blot analysis in both oocytes and embryos. Blastocyst adhesion on the endometrial cells was monitored by microscopic analysis. qRT-PCR results showed that Let-7a expression decreased in the IVM (GV-MII) oocytes compared to the in vivo oocyte (MII) group (p < .05). TLR4 showed a higher expression in GV-MII oocytes at both the gene and protein levels (p < .05). Following anti-miR-Let-7a transmission, the TLR4 expression level was significantly upregulated in embryos compared with the control groups (p < .05). Attachment and migration of trophoblasts cells towards endometrial cells dramatically increased compared to the control group (p < .05). Based on our results, we concluded that Let-7a might mediate embryo attachment through regulation of TLR4 expression levels.

The Importance of Stem Cell Senescence in Regenerative Medicine.

Mesenchymal stem cells (MSCs) are an interesting tool in regenerative medicine and a unique cell-based therapy to treat aging-associated diseases. Successful MSC therapy needs a large-scale cell culture, and requires a prolonged in vitro cell culture that subsequently leads to cell senescence. Administration of senescent MSCs results in inefficient cell differentiation in the clinical setting. Therefore, it is of utmost importance to enhance our knowledge about the aging process and methods to detect cell senescence in order to overcome this challenge. Numerous studies have addressed senescence in various aspects. Here, we review the characteristics of MSCs, how aging affects their features, mechanisms involved in aging of MSCs, and potential approaches to detect MSC senescence in vitro.

Targeted cell delivery for articular cartilage regeneration and osteoarthritis treatment.

Osteoarthritis (OA) is one of the main causes of pain and disability worldwide. In recent years, numerous efforts have been made in pharmaceutical and surgical therapies for OA management. The therapeutic features of mesenchymal stem cells (MSCs), have led to numerous preclinical and clinical trials that confirmed the efficacy of cell therapy as treatment for OA. Recent works have attempted to customize cell participation in tissue regeneration using site specific targeting approaches. Targeting approaches are based on direct modifications to the surface of MSCs or indirect modifications on an engineered nanomediator. Here, we provide a comprehensive review of the advances in targeted cell delivery and define the priorities for future work in terms of OA and cartilage regeneration.

Cannabidiol-loaded microspheres incorporated into osteoconductive scaffold enhance mesenchymal stem cell recruitment and regeneration of critical-sized bone defects.

Recruitment of mesenchymal stem cells (MSCs) to an injury site and their differentiation into the desired cell lineage are implicated in deficient bone regeneration. To date, there is no ideal structure that provides these conditions for bone regeneration. In the current study, we aim to develop a novel scaffold that induces MSC migration towards the defect site, followed by their differentiation into an osteogenic lineage. We have fabricated a gelatin/nano-hydroxyapatite (G/nHAp) scaffold that delivered cannabidiol (CBD)-loaded poly (lactic-co-glycolic acid) (PLGA) microspheres to critical size radial bone defects in a rat model. The fabricated scaffolds were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and then analyzed for porosity and degradation rate. The release profile of CBD from the PLGA microsphere and CBD-PLGA-G/nHAp scaffold was analyzed by fluorescence spectroscopy. We performed an in vitro assessment of the effects of CBD on cellular behaviors of viability and osteogenic differentiation. Radiological evaluation, histomorphometry, and immunohistochemistry (IHC) analysis of all defects in the scaffold and control groups were conducted following transplantation into the radial bone defects. An in vitro migration assay showed that CBD considerably increased MSCs migration. qRT-PCR results showed upregulated expression of osteogenic markers in the presence of CBD. Histological and immunohistochemical findings confirmed new bone formation and reconstruction of the defect at 4 and 12 week post-surgery (WPS) in the CBD-PLGA-G/nHAp group. Immunofluorescent analysis revealed enhanced migration of MSCs into the defect areas in the CBD-PLGA-G/nHAp group in vivo. Based on the results of the current study, we concluded that CBD improved bone healing and showed a critical role for MSC migration in the bone regeneration process.

In Vitro and In Vivo Comparison of Different Types of Rabbit Mesenchymal Stem Cells for Cartilage Repair.

OBJECTIVE: Systematic studies indicate a growing number of clinical studies that use mesenchymal stem cells (MSCs) for the treatment of cartilage lesions. The current experimental and preclinical study aims to comparatively evaluate the potential of MSCs from a variety of tissues for the treatment of cartilage defect in rabbit's knee which has not previously been reported. MATERIALS AND METHODS: In this experimental study, MSCs isolated from bone marrow (BMMSCs), adipose (AMSCs), and ears (EMSCs) of rabbits and expanded under in vitro culture. The growth rate and differentiation ability of MSCs into chondrocyte and the formation of cartilage pellet were investigated by drawing the growth curve and real-time polymerase chain reaction (RT-PCR), respectively. Then, the critical cartilage defect was created on the articular cartilage (AC) of the rabbit distal femur, and MSCs in collagen carrier were transplanted. The studied groups were as the control (only defect), sham (defect with scaffold), BMMSCs in the scaffold, EMSCs in the scaffold, and EMSCs in the scaffold with cartilage pellets. Histological and the gene expression analysis were performed following the transplantation. RESULTS: Based on our comparative in vitro investigation, AMSCs possessed the highest growth rate, as well as the lowest chondrogenic differentiation potential. In this context, MSCs of the ear showed a significantly higher growth rate and cartilage differentiation potential than those of bone marrow tissue (P<0.05). According to our in vivo assessments, BMMSC- and EMSC-seeded scaffolds efficiently improved the cartilage defect 4 weeks post-transplantation, while no improvement was observed in the group contained the cartilage pellets. CONCLUSION: It seems that the ear contains MSCs that promote cartilage regeneration as much as the conventional MSCs from the bone marrow. Considering a high proliferation rate and easy harvesting of MSCs of the ear, this finding could be of value for the regenerative medicine.

Synergistic effect of strontium, bioactive glass and nano-hydroxyapatite promotes bone regeneration of critical-sized radial bone defects.

Critical-sized bone defects constitute a major health issue in orthopedics and usually cause mal-unions due to an inadequate number of migrated progenitor cells into the defect site or their incomplete differentiation into osteogenic precursor cells. The current study aimed to develop an optimized osteoinductive and angiogenic scaffold by incorporation of strontium (Sr) and bioglass (BG) into gelatin/nano-hydroxyapatite (G/nHAp) seeded with bone marrow mesenchymal stem cells to enhance bone regeneration. The scaffolds were fabricated by a freeze-drying technique and characterized in terms of morphology, structure, porosity and degradation rate. The effect of fabricated scaffolds on cell viability, attachment and differentiation into osteoblastic lineages was evaluated under in vitro condition. Micro computed tomography scan, histological and histomorphometric analysis were performed after implantation of scaffolds into the radial bone defects in rat. RT-PCR analysis showed that G/nHAp/BG/Sr scaffold significantly increased the expression level of osteogenic and angiogenic markers in comparison to other groups (P < 0.05). Moreover, the defects treated with the BMSCs-seeded scaffolds showed superior bone formation and mechanical properties compared to the cell-free scaffolds 4 and 12 weeks post-implantation. Finally, the BMSCs-seeded G/nHAp/BG/Sr scaffold showed the greatest bone regenerative capacity which was more similar to autograft. It is concluded that combination of Sr, BG, and nHAp can synergistically enhance the bone regeneration process. In addition, our results demonstrated that the BMSCs have the potential to considerably increase the bone regeneration ability of osteoinductive scaffolds. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 50-64, 2019.

The Robust Potential of Mesenchymal Stem Cell-Loaded Constructs for Hard Tissue Regeneration After Cancer Removal.

Malignant bone tumors, although quite rare, are one of the causes of death in children and adolescents. Surgery as a common and primary treatment for removal of virtually bone cancer cause large bone defects. Thus, restoration of hard tissues like bone and cartilage after surgical tumor resection needs efficient therapeutic approaches. Tissue engineering (TE) is a powerful approach which has provided hope for restoration, maintenance, or improvement of damaged tissues. This strategy generally supplies a three-dimensional scaffold as an active substrate to support cell recruitment, infiltration, and proliferation for neo-tissues. The scaffold mimics the natural extracellular matrix (ECM) of tissue which needs to be regenerated. The use of potent cell sources such as mesenchymal stem cells (MSCs) has also led to remarkable progresses in hard tissue regeneration. Combination of living cells and various biomaterials have continuously evolved over the past decades to improve the process of regeneration. This chapter describes various strategies used in TE and highlights recent advances in cell-loaded constructs. We herein focus on cell-based scaffold approach utilized in hard tissue engineering and parameters determining a clinically efficient outcome. Also, we attempt to identify the potential as well as shortcomings of pre-loaded scaffolds for future therapeutic applications.

Contribution of osteocalcin-mimetic peptide enhances osteogenic activity and extracellular matrix mineralization of human osteoblast-like cells.

A natural peptide motif in the first helix of osteocalcin (OCN) is used to promote nucleation and crystallization of hydroxyapatite (HA) in hard tissue. The capability of osteocalcin mimetic peptides to induce osteogenic activity of osteoblast cells leading to in-vitro mineralization is demonstrated. An osteocalcin-derived peptide consisting of thirteen amino acids is synthesized in both acidic (OSC) and amidic (OSN) forms and added into the human osteoblast-like cells (MG63) culture. The viability, proliferation, alkaline phosphatase activity, HA deposition and osteogenic gene expression by osteoblast cells are evaluated. It is revealed that the addition of 100 µg/ml of peptides enhances the proliferation rate and total protein content of osteoblast cells. Alkaline phosphatase activity is significantly higher in the presence of peptides which in turn stimulated RNA expression of collagen type I and osteopontin in a phosphate-dependent manner. Alizarin red staining and calcium content measurement show that mineral deposition is considerably increased. Ultrastructural characterization of MG63 cultures confirms the crystalline nature and chemical composition of HA mineral formation in the presence of peptides. It is confirmed that the osteocalcin-derived peptide, particularly in amidic form (OSN), is able to act as a bioactive inducer of mineralization process and hence accelerating bone tissue regeneration.