Comprehensive Review of Adipose Stem Cells and Their Implication in Distraction Osteogenesis and Bone Regeneration. Biomed Res Int. 2015;2015:842975. [PMID: 26448947 PMCID: PMC4584039 DOI: 10.1155/2015/842975]

Application of chemical factors for acceleration of consolidation phase of the distraction osteogenesis: a scoping review

PURPOSE

This study aimed to analyze the effect of injecting chemical factors compared to conventional distraction osteogenesis (DO) treatment on the bone formation of the distracted area of the maxillofacial region in human and animal studies.

METHOD

Electronic search was done in PubMed, Scopus, Embase, and Cochrane database for studies published until September 2021. The studies' risk of bias (ROB) was assessed using the Cochrane Collaborations and NIH quality assessment tools. Meta-analyses were performed to assess the difference in the amount of bone formation and maximal load tolerance.

RESULTS

Among a total of 58 included studies, eight studies analyzed the bone formation rate of the distracted area in human models and others in animal models. Results of the human studies showed acceptable outcomes in the case of using bone morphogenic protein-2 (BMP-2), autologous bone-platelet gel, and calcium sulfate. However, using platelet reach plasma does not increase the rate of bone formation significantly. Quantitative analyses showed that both BMP-2 (SMD = 26.57; 95% CI = 18.86 to 34.28) and neuron growth factor (NGF) (SMD = 16.19; 95% CI = 9.64 to 22.75) increase the amount of bone formation. Besides, NGF increased the amount of load tolerance significantly (SMD = 30.03; 95% CI = 19.91 to 40.16). Additionally, BMP-2 has no significant impact on the post-treatment maxillary length (SMD = 9.19; 95% CI =  - 2.35 to 20.73).

CONCLUSION

Limited number of human studies with low quality used chemical factors to enhance osteogenesis and showed acceptable results. However, more studies with higher quality are required.

Osteoblast-derived extracellular vesicles exert osteoblastic and tumor-suppressive functions via SERPINA3 and LCN2 in prostate cancer

Clinically, the osteolytic phenotype is rare in prostate cancer (PCa), and the prognosis is generally worse than that of the osteoblastic phenotype. Osteoblastic prostate cancer (BPCa) is a major type of bone metastasis. Several factors responsible for osteogenesis have been identified, but the molecular mechanism of osteoblastic bone metastasis in PCa is not fully understood. Here, we show the osteogenic and tumor-suppressive roles of SERPINA3 and LCN2 in BPCa. In a co-culture of osteoblasts (OBs) and BPCa cells, SERPINA3 and LCN2 were remarkably upregulated in BPCa via OB-derived extracellular vesicles, while they were not in the co-culture of OBs and osteolytic prostate cancer (LPCa) cells. In both the co-culture system and mouse xenograft experiments with intracaudal injection, enhanced expression of SERPINA3 and LCN2 in PCa led to osteogenesis. Additionally, the addition of SERPINA3 and LCN2 to BPCa cells significantly suppressed the proliferative potential. Retrospective analysis also confirmed that high expression levels of SERPINA3 and LCN2 were significantly correlated with a better prognosis. Our results may partially explain how osteoblastic bone metastasis develops and why the prognosis for BPCa is relatively better than that for LPCa.

Mesenchymal Stem Cell Studies in the Goat Model for Biomedical Research-A Review of the Scientific Literature

Mesenchymal stem cells (MSCs) are multipotent cells, defined by their ability to self-renew, while maintaining the capacity to differentiate into different cellular lineages, presumably from their own germinal layer. MSCs therapy is based on its anti-inflammatory, immunomodulatory, and regenerative potential. Firstly, they can differentiate into the target cell type, allowing them to regenerate the damaged area. Secondly, they have a great immunomodulatory capacity through paracrine effects (by secreting several cytokines and growth factors to adjacent cells) and by cell-to-cell contact, leading to vascularization, cellular proliferation in wounded tissues, and reducing inflammation. Currently, MSCs are being widely investigated for numerous tissue engineering and regenerative medicine applications. Appropriate animal models are crucial for the development and evaluation of regenerative medicine-based treatments and eventual treatments for debilitating diseases with the hope of application in upcoming human clinical trials. Here, we summarize the latest research focused on studying the biological and therapeutic potential of MSCs in the goat model, namely in the fields of orthopedics, dermatology, ophthalmology, dentistry, pneumology, cardiology, and urology fields.

Characterization and functional analysis of the adipose tissue-derived stromal vascular fraction of pediatric patients with osteogenesis imperfecta

Pediatric patients with Osteogenesis Imperfecta (OI), a heritable connective tissue disorder, frequently suffer from long bone deformations. Surgical correction often results in bone non-unions, necessitating revision surgery with autogenous bone grafting using bone-marrow-derived stem cells (BM-SC) to regenerate bone. BM-SC harvest is generally invasive and limited in supply; thus, adipose tissue's stromal vascular fraction (SVF) has been introduced as an alternative stem cell reservoir. To elucidate if OI patients' surgical site dissected adipose tissue could be used as autologous bone graft in future, we investigated whether the underlying genetic condition alters SVF's cell populations and in vitro differentiation capacity. After optimizing SVF isolation, we demonstrate successful isolation of SVF of pediatric OI patients and non-OI controls. The number of viable cells was comparable between OI and controls, with about 450,000 per gram tissue. Age, sex, type of OI, disease-causing collagen mutation, or anatomical site of harvest did not affect cell outcome. Further, SVF-containing cell populations were similar between OI and controls, and all isolated SVF's demonstrated chondrogenic, adipogenic, and osteogenic differentiation capacity in vitro. These results indicate that SVF from pediatric OI patients could be used as a source of stem cells for autologous stem cell therapy in OI.

Immunomodulatory effects and mechanisms of distraction osteogenesis

Distraction osteogenesis (DO) is widely used for bone tissue engineering technology. Immune regulations play important roles in the process of DO like other bone regeneration mechanisms. Compared with others, the immune regulation processes of DO have their distinct features. In this review, we summarized the immune-related events including changes in and effects of immune cells, immune-related cytokines, and signaling pathways at different periods in the process of DO. We aim to elucidated our understanding and unknowns about the immunomodulatory role of DO. The goal of this is to use the known knowledge to further modify existing methods of DO, and to develop novel DO strategies in our unknown areas through more detailed studies of the work we have done.

Cell and Cell Free Therapies in Osteoarthritis

Osteoarthritis (OA) is the most common articular disease in adults and has a current prevalence of 12% in the population over 65 years old. This chronic disease causes damage to articular cartilage and synovial joints, causing pain and leading to a negative impact on patients' function, decreasing quality of life. There are many limitations regarding OA conventional therapies-pharmacological therapy can cause gastrointestinal, renal, and cardiac adverse effects, and some of them could even be a threat to life. On the other hand, surgical options, such as microfracture, have been used for the last 20 years, but hyaline cartilage has a limited regeneration capacity. In recent years, the interest in new therapies, such as cell-based and cell-free therapies, has been considerably increasing. The purpose of this review is to describe and compare bioregenerative therapies' efficacy for OA, with particular emphasis on the use of mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP). In OA, these therapies might be an alternative and less invasive treatment than surgery, and a more effective option than conventional therapies.

Encapsulation and differentiation of adipose-derived mesenchymal stem cells in a biomimetic purine cross-linked chitosan sponge

Mesenchymal stem cells derived from adipose tissue have become a widely investigated cell source to use in tissue engineering applications. However, an optimal delivery scaffold for these cells is still needed. A rapidly gelling, injectable chitosan sponge was proposed in this study as a potential candidate for a suitable delivery scaffold. The results demonstrated the ability to encapsulate the stem cells at a 97.6% encapsulation efficiency and that the cells maintain their viability within the sponge. With the potential of using this scaffold for bone tissue engineering, ALP activity assay and fluorescent imaging for osteocalcin proved the ability to differentiate the encapsulated cells into the osteogenic lineage. Furthermore, co-encapsulation of pyrophosphatase within the sponge was investigated as a method to overcome the inhibitory effects that the sponge degradation by-products have on mineralization. Alizarin Red S staining demonstrated the beneficial effects of adding pyrophosphatase, where a significant increase in mineralization levels was achieved.

Mesenchymal stem cells for enhancing biological healing after meniscal injuries

The meniscus is a semilunar fibrocartilage structure that plays important roles in maintaining normal knee biomechanics and function. The roles of the meniscus, including load distribution, force transmission, shock absorption, joint stability, lubrication, and proprioception, have been well established. Injury to the meniscus can disrupt overall joint stability and cause various symptoms including pain, swelling, giving-way, and locking. Unless treated properly, it can lead to early degeneration of the knee joint. Because meniscal injuries remain a significant challenge due to its low intrinsic healing potential, most notably in avascular and aneural inner two-thirds of the area, more efficient repair methods are needed. Mesenchymal stem cells (MSCs) have been investigated for their therapeutic potential in vitro and in vivo. Thus far, the application of MSCs, including bone marrow-derived, synovium-derived, and adipose-derived MSCs, has shown promising results in preclinical studies in different animal models. These preclinical studies could be categorized into intra-articular injection and tissue-engineered construct application according to delivery method. Despite promising results in preclinical studies, there is still a lack of clinical evidence. This review describes the basic knowledge, current treatment, and recent studies regarding the application of MSCs in treating meniscal injuries. Future directions for MSC-based approaches to enhance meniscal healing are suggested.

Clinical application of mesenchymal stem cells therapy in musculoskeletal injuries in dogs-a review of the scientific literature

Mesenchymal stem cells (MSCs) are multipotent, which is defined by their ability to self-renew while maintaining the capacity to differentiate into a certain number of cells, presumably from their own germinal layer. MSCs therapy is based on their anti-inflammatory, immunomodulatory (immunosuppressive), and regenerative potential. This review aims to provide a clinical overview of the MSCs potential as a therapeutic option for orthopedic diseases in dogs. A total of 25 clinical studies published in the scientific literature in the last 15 years on various diseases will be presented: semitendinosus myopathy, supraspinatus tendinopathy, cruciate ligament rupture, bone fractures and defects, and also osteoarthritis (OA). All articles involved in this study include only diseases that have naturally occurred in canine patients. MSCs therapy in the veterinary orthopedic field has great potential, especially for OA. All studies presented promising results. However, MSCs bone healing capacity did not reveal such favorable outcomes in the long term. Besides, most of these clinical studies did not include immunohistochemistry, immunofluorescence, and histopathology to confirm that MSCs have differentiated and incorporated into the injured tissues. This review summarizes the current knowledge of canine MSCs biology, immunology, and clinical application in canine orthopedic diseases. Despite the positive results in its use, there is still a lack of defined protocols, heterogeneous samples, and concomitant medications used with MSCs therapy compromising therapeutic effects. Further studies are needed in the hope of overcoming its limitation in upcoming trials.

Adipose-derived stem cells: An appropriate selection for osteogenic differentiation

Mesenchymal stem cells (MSCs) are a major component of various forms of tissue engineering. MSCs have self-renewal and multidifferential potential. Osteogenic differentiation of MSCs is an area of attention in bone regeneration. One form of MSCs are adipose-derived stem cells (ASCs), which can be simply harvested and differentiated into several cell lineages, such as chondrocytes, adipocytes, or osteoblasts. Due to special properties, ASCs are frequently used in vitro and in vivo bone regeneration. Identifying factors involved in osteogenic differentiation of ASCs is important for better understanding the mechanism of osteogenic differentiation. Different methods are used to stimulate osteogenesis of ASCs in literature, including common osteogenic media, growth factors, hormones, hypoxia, mechanical and chemical stimuli, genetic modification, and nanotechnology. This review article provides an overview describing the isolation procedure, characterization, properties, current methods for osteogenic differentiation of ASCs, and their basic biological mechanism.

Overexpression of Bone Morphogenetic Protein-1 Promotes Osteogenesis of Bone Marrow Mesenchymal Stem Cells In Vitro

BACKGROUND Osteogenesis of bone marrow mesenchymal stem cells (BMSCs) is an important research topic in the application of bone tissue engineering. Bone morphogenetic protein-1 (BMP-1) is important in bone formation and stability, but its effects on the osteogenesis of BMSCs are unclear. This study aimed to investigate the association of BMP-1 with the osteogenic capacity of BMSCs. MATERIAL AND METHODS Primary rabbit BMSCs were cultured and divided into a BMP-1-overexpressing group, a Green Fluorescent Protein-expressing (GFP) group, and a Control group. The transfection efficiency of BMP-1 was tested by Western blotting. Cell viabilities, alkaline phosphatase (ALP) activities, Ca2+ concentrations, and gross examinations of BMSC sheets were examined at different times. The osteogenic marker collagen I was assessed by immunohistochemical analysis. RESULTS The cell viability, ALP activity, and Ca2+ content of the BMP1-overexpressed group were significantly enhanced compared with the GFP group and Control group. Immunohistochemistry staining results showed that BMP-1 promoted the expression of type I collagen in BMSCs sheets. CONCLUSIONS Our results suggest that the overexpression of BMP-1 can promote the osteogenesis of BMSCs and provides an improved method of cell-based tissue engineering.

Bone allografts combined with adipose-derived stem cells in an optimized cell/volume ratio showed enhanced osteogenesis and angiogenesis in a murine femur defect model

Critical sized defects, especially in long bones, pose one of the biggest problems in orthopedic surgery. By definition, these defects do not heal without further treatment. Different therapeutic options range from autologous bone grafts, for example, free vascularized bone grafts, to commercially available bone allografts. Disadvantages of these bone allografts are related to reduced osteogenesis, since they are solely composed of cell-free bone matrix. The purpose of this study was to investigate the cell seeding efficiency of human adipose-derived stem cells (hASCs) on human bone allografts in vitro and furthermore analyze these optimized seeded allografts in a critical sized defect model in vivo. Cancellous human bone allografts were colonized with human ASCs in vitro. Cell seeding efficiency was evaluated by Cell Counting Kit-8 assay. Thereafter, optimized hASC-seeded bone scaffolds were examined in a murine femur defect model, stabilized with the MouseExFix system. Subsequently, x-ray analysis and histology were performed. Examination of cell seeding efficiency revealed an optimum starting population of 84,600 cells per 100 mm³ scaffold. In addition, scaffolds seeded with hASCs showed increased osteogenesis compared with controls. Histological analysis revealed increased remodeling and elevated new bone formation within hASC-seeded scaffolds. Moreover, immunohistochemical stainings revealed increased proliferation, osteogenesis, and angiogenesis. In this study, we systemically optimized cell/volume ratio of two promising components of tissue engineering: hASCs and human bone allografts. These findings may serve as a basis for future translational studies. KEY MESSAGES: Bone tissue engineering. Mesenchymal stem cells derived from human adipose tissue (hASCs). Optimal cell/volume ratio of cell-seeded scaffolds. Increased osteogenesis and angiogenesis in vivo.

Adipose-Derived Mesenchymal Stem Cells: A Promising Tool in the Treatment of Musculoskeletal Diseases

Chronic musculoskeletal (MSK) pain is one of the most common medical complaints worldwide and musculoskeletal injuries have an enormous social and economical impact. Current pharmacological and surgical treatments aim to relief pain and restore function; however, unsatiscactory outcomes are commonly reported. In order to find an accurate treatment to such pathologies, over the last years, there has been a significantly increasing interest in cellular therapies, such as adipose-derived mesenchymal stem cells (AMSCs). These cells represent a relatively new strategy in regenerative medicine, with many potential applications, especially regarding MSK disorders, and preclinical and clinical studies have demonstrated their efficacy in muscle, tendon, bone and cartilage regeneration. Nevertheless, several worries about their safety and side effects at long-term remain unsolved. This article aims to review the current state of AMSCs therapy in the treatment of several MSK diseases and their clinical applications in veterinary and human medicine.

Bone Tissue Engineering Using Human Cells: A Comprehensive Review on Recent Trends, Current Prospects, and Recommendations

The use of proper cells for bone tissue engineering remains a major challenge worldwide. Cells play a pivotal role in the repair and regeneration of the bone tissue in vitro and in vivo. Currently, a large number of differentiated (somatic) and undifferentiated (stem) cells have been used for bone reconstruction alone or in combination with different biomaterials and constructs (e.g., scaffolds). Although the results of the cell transplantation without any supporting or adjuvant material have been very effective with regard to bone healing. Recent advances in bone scaffolding are now becoming new players affecting the osteogenic potential of cells. In the present study, we have critically reviewed all the currently used cell sources for bone reconstruction and discussed the new horizons that are opening up in the context of cell-based bone tissue engineering strategies.

Enhancement of osteogenic differentiation of adipose-derived stem cells by PRP modified nanofibrous scaffold

Recent developments in bone tissue engineering have paved the way for more efficient and cost-effective strategies. Additionally, utilization of autologous sources has been considered very desirable and is increasingly growing. Recently, activated platelet rich plasma (PRP) has been widely used in the field of bone tissue engineering, since it harbours a huge number of growth factors that can enhance osteogenesis and bone regeneration. In the present study, the osteogenic effects of PRP coated nanofibrous PES/PVA scaffolds on adipose-derived mesenchymal stem cells have been investigated. Common osteogenic markers were assayed by real time PCR. Alkaline phosphate activity, calcium deposition and Alizarin red staining assays were performed as well. The results revealed that the highest osteogenic differentiation occurred when cells were cultured on PRP coated PES/PVA scaffolds. Interestingly, direct application of PRP to culture media had no additive effects on osteogenesis of cells cultured on PRP coated PES/PVA scaffolds or those receiving typical osteogenic factors. The highest osteogenic effects were achieved by the simplest and most cost-effective method, i.e. merely by using PRP coated scaffolds. PRP coated PES/PVA scaffolds can maximally induce osteogenesis with no need for extrinsic factors. The major contribution of this paper to the current researches on bone regeneration is to suggest an easy, cost-effective approach to enhance osteogenesis via PRP coated scaffolds, with no additional external growth factors.

Let-7c regulates proliferation and osteodifferentiation of human adipose-derived mesenchymal stem cells under oxidative stress by targeting SCD-1

Osteoporosis is a progressive bone disease characterized by decreased bone mass and density, which usually parallels a reduced antioxidative capacity and increased reactive oxygen species formation. Adipose-derived mesenchymal stem cells (ADMSCs), a population of self-renewing multipotent cells, are a well-recognized source of potential bone precursors with significant clinical potential for tissue regeneration. We previously showed that overexpressing stearoyl-CoA desaturase 1 (SCD-1) promotes osteogenic differentiation of mesenchymal stem cells. Micro-RNAs (miRNAs) are noncoding RNAs recently recognized to play key roles in many developmental processes, and miRNA let-7c is downregulated during osteoinduction. We found that let-7c was upregulated in the serum of patients with postmenopausal osteoporosis compared with healthy controls. Levels of let-7c during osteogenic differentiation of ADMSCs were examined under oxidative stress in vitro and found to be upregulated. Overexpression of let-7c inhibited osteogenic differentiation, whereas inhibition of let-7c function promoted this process, evidenced by increased expression of osteoblast-specific genes, alkaline phosphatase activity, and matrix mineralization. The luciferase reporter assay was used to validate SCD-1 as a target of let-7c. Further experiments showed that silencing of SCD-1 significantly attenuated the effect of let-7c inhibitor on osteoblast markers, providing strong evidence that let-7c modulates osteogenic differentiation by targeting SCD-1. Inhibition of let-7c promoted the translocation of β-catenin into nuclei, thus activating Wnt/β-catenin signaling. Collectively, these data suggest that let-7c is induced under oxidative stress conditions and in osteoporosis, reducing SCD-1 protein levels, switching off Wnt/β-catenin signaling, and inhibiting osteogenic differentiation. Thus, let-7c may be a potential therapeutic target in the treatment of osteoporosis and especially postmenopausal osteoporosis.

Biomaterials Enabled Cell-Free Strategies for Endogenous Bone Regeneration

Repairing bone defects poses a major orthopedic challenge because current treatments are constrained by the limited regenerative capacity of human bone tissue. Novel therapeutic strategies, such as stem cell therapy and tissue engineering, have the potential to enhance bone healing and regeneration, and hence may improve quality of life for millions of people. However, the ex vivo expansion of stem cells and their in vivo delivery pose technical difficulties that hamper clinical translation and commercial development. A promising alternative to cell delivery-based strategies is to stimulate or augment the inherent self-repair mechanisms of the patient to promote endogenous restoration of the lost/damaged bone. There is growing evidence indicating that increasing the endogenous regenerative potency of bone tissues for therapeutics will require the design and development of new generations of biomedical devices that provide key signaling molecules to instruct cell recruitment and manipulate cell fate for in situ tissue regeneration. Currently, a broad range of biomaterial-based deployment technologies are becoming available, which allow for controlled spatial presentation of biological cues required for endogenous bone regeneration. This article aims to explore the proposed concepts and biomaterial-enabled strategies involved in the design of cell-free endogenous techniques in bone regenerative medicine.

Osteogenic Effect and Cell Signaling Activation of Extremely Low-Frequency Pulsed Electromagnetic Fields in Adipose-Derived Mesenchymal Stromal Cells

Extremely low-frequency pulsed electromagnetic field (ELF-PEMF) devices have been used in the clinic for the treatment of bone disorders over the past 30 years. However, the underlying mechanism of which ELF-PEMFs exert an effect on tissues at a cellular level is not well understood. Hence, in this study, we explored the potential of different ELF-PEMF signals in modulating human adipose-derived mesenchymal stromal cells' (hAMSC) osteogenic capability. The cell proliferation rate was assessed using carboxyfluorescein succinimidyl ester (CFSE) method. The osteogenesis potential of cells was determined by alkaline phosphatase (ALP) activity, Alizarin-Red S staining, and RT-qPCR. Finally, the intracellular signaling pathway of a selected ELF-PEMF signal was examined using the PathScan Intracellular Signaling Array. Among the tested ELF-PEMF signals, program 20 (26 Hz) showed activation of the Akt and MAPK/ERK signaling cascade and significant upregulations of collagen I, alkaline phosphatase, and osteocalcin when compared to nonstimulated cells. This study demonstrates the potential of certain ELF-PEMF signal parameters to induce osteogenic differentiation of hAMSC and provides important clues in terms of the molecular mechanisms for the stimulation of osteogenic effects by ELF-PEMF on hAMSC.

An Efficient and Reproducible Protocol for Distraction Osteogenesis in a Rat Model Leading to a Functional Regenerated Femur

This protocol describes the use of a newly developed external fixator for distraction osteogenesis in a rat femoral model. Distraction osteogenesis (DO) is a surgical technique leading to bone regeneration after an osteotomy. The osteotomized extremities are moved away from each other by gradual distraction to reach the desired elongation. This procedure is widely used in humans for lower and upper limb lengthening, treatment after a bone nonunion, or the regeneration of a bone defect following surgery for bone tumor excision, as well as in maxillofacial reconstruction. Only a few studies clearly demonstrate the efficiency of their protocol in obtaining a functional regenerated bone, i.e., bone that will support physiological weight-bearing without fracture after removal of the external fixator. Moreover, protocols for DO vary and reproducibility is limited by lack of information, making comparison between studies difficult. The aim of this study was to develop a reproducible protocol comprising an appropriate external fixator design for rat limb lengthening, with a detailed surgical technique that permits physiological weight-bearing by the animal after removal of the external fixator.

Adipose Tissue as a Strategic Source of Mesenchymal Stem Cells in Bone Regeneration: A Topical Review on the Most Promising Craniomaxillofacial Applications

Bone regeneration in craniomaxillofacial surgery represents an issue that involves both surgical and aesthetic aspects. The most recent studies on bone tissue engineering involving adipose-derived stromal/stem cells (ASCs) have clearly demonstrated that such cells can play a crucial role in the treatment of craniomaxillofacial defects, given their strong commitment towards the osteogenic phenotype. A deeper knowledge of the molecular mechanisms underlying ASCs is crucial for a correct understanding of the potentialities of ASCs-based therapies in the most complex maxillofacial applications. In this topical review, we analyzed the molecular mechanisms of ASCs related to their support toward angiogenesis and osteogenesis, during bone regeneration. Moreover, we analyzed both case reports and clinical trials reporting the most promising clinical applications of ASCs in the treatment of craniomaxillofacial defects. Our study aimed to report the main molecular and clinical features shown by ASCs, used as a therapeutic support in bone engineering, as compared to the use of conventional autologous and allogeneic bone grafts.

MicroRNA-144-3p inhibits bone formation in distraction osteogenesis through targeting Connexin 43

Distraction osteogenesis (DO), one of effective therapies for bone regeneration, has been received more attention in recent years. However, the underlying mechanism remains elusive. Recently, microRNAs (miRNAs) have been reported to play important roles in regulating osteogenesis and bone formation. We therefore provided the hypothesis that miRNAs could involve in the DO-mediated bone regeneration. After successfully established the DO model of rats, a miRNA microarray was performed to find the differently expressed miRNAs in DO and control groups in this study. As one of the most downregulated miRNAs, miR-144-3p was found to be decreased during osteogenic differentiation in mesenchymal stem cells of rats (rBMSCs) and DO model. And miR-144-3p overexpression suppressed the osteogenesis while its inhibitor promoted osteogenesis. Furthermore, Connexin-43, an essential regulator for osteogenesis, was validated to be a novel target for miR-144-3p. Finally, miR-144-3p inhibitor modified MSCs promoted mineralization of distracted bone in rat DO model. In conclusion, miR-144-3p was found to regulate osteogenesis and inhibition of miR-144-3p resulted in acceleration of mineralization of DO, which not only give clues to understanding the mechanism of DO but also provide a potential therapeutic target in clinical practice.

Red (660 nm) or near-infrared (810 nm) photobiomodulation stimulates, while blue (415 nm), green (540 nm) light inhibits proliferation in human adipose-derived stem cells

We previously showed that blue (415 nm) and green (540 nm) wavelengths were more effective in stimulating osteoblast differentiation of human adipose-derived stem cells (hASC), compared to red (660 nm) and near-infrared (NIR, 810 nm). Intracellular calcium was higher after blue/green, and could be inhibited by the ion channel blocker, capsazepine. In the present study we asked what was the effect of these four wavelengths on proliferation of the hASC? When cultured in proliferation medium there was a clear difference between blue/green which inhibited proliferation and red/NIR which stimulated proliferation, all at 3 J/cm². Blue/green reduced cellular ATP, while red/NIR increased ATP in a biphasic manner. Blue/green produced a bigger increase in intracellular calcium and reactive oxygen species (ROS). Blue/green reduced mitochondrial membrane potential (MMP) and lowered intracellular pH, while red/NIR had the opposite effect. Transient receptor potential vanilloid 1 (TRPV1) ion channel was expressed in hADSC, and the TRPV1 ligand capsaicin (5uM) stimulated proliferation, which could be abrogated by capsazepine. The inhibition of proliferation caused by blue/green could also be abrogated by capsazepine, and by the antioxidant, N-acetylcysteine. The data suggest that blue/green light inhibits proliferation by activating TRPV1, and increasing calcium and ROS.

Stem cell therapy for enhancement of bone consolidation in distraction osteogenesis: A contemporary review of experimental studies

Objectives

Distraction osteogenesis (DO) mobilises bone regenerative potential and avoids the complications of other treatments such as bone graft. The major disadvantage of DO is the length of time required for bone consolidation. Mesenchymal stem cells (MSCs) have been used to promote bone formation with some good results.

Methods

We hereby review the published literature on the use of MSCs in promoting bone consolidation during DO.

Results

Studies differed in animal type (mice, rabbit, dog, sheep), bone type (femur, tibia, skull), DO protocols and cell transplantation methods.

Conclusion

The majority of studies reported that the transplantation of MSCs enhanced bone consolidation or formation in DO. Many questions relating to animal model, DO protocol and cell transplantation regime remain to be further investigated. Clinical trials are needed to test and confirm these findings from animal studies.

Cite this article: Y. Yang, S. Lin, B. Wang, W. Gu, G. Li. Stem cell therapy for enhancement of bone consolidation in distraction osteogenesis: A contemporary review of experimental studies. Bone Joint Res 2017;6:385–390. DOI: 10.1302/2046-3758.66.BJR-2017-0023.

WNT3A and the induction of the osteogenic differentiation in adipose tissue derived mesenchymal stem cells

Adipose tissue derived stem cells (ASCs) can easily be isolated, but the osteogenic differentiation potential is limited. To improve this differentiation potential, more investigations are required about signaling proteins for the induction of the osteogenic differentiation. This study focused on the WNT3A protein, because little is known about the canonical WNT signaling pathway and the osteogenic differentiation of ASCs. The alkaline phosphatase (ALP) activity was measured for the evaluation of the osteogenic differentiation. WNT3A and Dickkopf-related protein 1 (DKK1) were used for the activation and the inhibition of the canonical WNT signaling pathway, respectively. For control we manipulated the bone morphogenetic protein (BMP) pathway in ASCs with BMP2 and NOGGIN (BMP pathway inhibitor). WNT3A stimulated significantly the ALP activity in ASCs, while BMP2, DKK1 and NOGGIN did not induce highly the ALP activity in ASCs. Moreover, an osteogenic differentiation medium with dexamethasone and WNT3A increased the ALP activity, but the gene expression of osteoblast markers and the biomineralization after long-term cultures were not increased. In contrast, ASCs differentiated into adipocyte-like cells in all tested differentiation media. WNT3A did not repress the expression of the adipogenic transcription factor Peroxisome Proliferator-Activated Receptor Gamma (PPARG). In conclusion, WNT3A supports early stages such as the ALP activity, but it does neither improve later stages of the osteogenic differentiation nor it inhibits the genuine adipogenic differentiation of ASCs.

Challenges of bone tissue engineering in orthopaedic patients

Bone defects may impede normal biomechanics and the structural stability of bone as an organ. In many cases, the correction of bone defects requires extensive surgical intervention involving the use of bone-grafting techniques and other procedures in which healing is slow, there is a high risk of infection and considerable pain is provoked - with no guarantee of complete correction of the defect. Therefore, the search for surgical alternatives continues to present a major challenge in orthopaedic traumatology. The reamer-irrigator-aspirator (RIA) system, which was devised to avoid the problems that can arise with autograft harvesting from the iliac crest, consists of collecting the product of the femoral canal after reaming. The RIA technique improves osteogenic differentiation of mesenchymal stem cells, compared to bone marrow aspiration or cancellous bone harvesting from the iliac crest using a spoon. Another approach, the Masquelet technique, consists of reconstructing a long bone defect by means of an induced membrane grown onto an acrylic cement rod inserted to fill the defect; in a second surgical step, once the membrane is constituted, the cement rod is removed and cancellous autograft is used to fill the defect. Both in RIA and in the Masquelet technique, osteosynthesis is usually needed. Bone transportation by compression-distraction lengthening principles is commonly implemented for the treatment of large bone loss. However, complications are frequently encountered with these techniques. Among new techniques that have been proposed to address the problem of large bone loss, the application of stem cells in conjunction with tissue engineering techniques is very promising, as is the creation of personalised medicine (or precision medicine), in which molecular profiling technologies are used to tailor the therapeutic strategy, to ensure the right method is applied for the right person at the right time, after determining the predisposition to disease among the general population. All of the above techniques for addressing bone defects are discussed in this paper.

Potential Therapeutic Applications of Adipose-Derived Mesenchymal Stem Cells

Stem cells are subdivided into two main categories: embryonic and adult stem cells. In principle, pluripotent embryonic stem cells might differentiate in any cell types of the organism, whereas the potential of adult stem cells would be more restricted. Although adult stem cells from bone marrow have been initially the most extensively studied, those derived from human adipose tissue have been lately more widely investigated, because of several advantages. First, they can be easily obtained in large amounts from subcutaneous adipose tissue, with minimal pain and morbidity for the patients during harvesting. In addition, they feature low immunogenicity and can differentiate not only in cells of mesodermal lineage (adipocytes, osteoblasts, chondrocytes and muscle cells), but also in cells of other germ layers, such as neural or epithelial cells. As their multilineage differentiation capabilities are increasingly highlighted, their possible use in cell-based regenerative medicine is now broadly explored. In fact, starting from in vitro observations, many studies have already entered the preclinical and clinical phases. In this review, because of our main scientific interest, adipogenic, osteogenic, chondrogenic, and neurogenic differentiation abilities of adipose-derived mesenchymal stem cells, as well as their possible therapeutic applications, are chiefly focused. In addition, their ability to differentiate toward muscle, epithelial, pancreatic, and hepatic cells is briefly reported.

Photobiomodulation (blue and green light) encourages osteoblastic-differentiation of human adipose-derived stem cells: role of intracellular calcium and light-gated ion channels

Human adipose-derived stem cells (hASCs) have the potential to differentiate into several different cell types including osteoblasts. Photobiomodulation (PBM) or low level laser therapy (LLLT) using red or near-infrared wavelengths has been reported to have effects on both proliferation and osteogenic differentiation of stem cells. We examined the effects of delivering four different wavelengths (420 nm, 540 nm, 660 nm, 810 nm) at the same dose (3 J/cm²) five times (every two days) on hASCs cultured in osteogenic medium over three weeks. We measured expression of the following transcription factors by RT-PCR: RUNX2, osterix, and the osteoblast protein, osteocalcin. The 420 nm and 540 nm wavelengths were more effective in stimulating osteoblast differentiation compared to 660 nm and 810 nm. Intracellular calcium was higher after 420 nm and 540 nm, and could be inhibited by capsazepine and SKF96365, which also inhibited osteogenic differentiation. We hypothesize that activation of light-gated calcium ion channels by blue and green light could explain our results.

Advances in the Use of Stem Cells in Veterinary Medicine: From Basic Research to Clinical Practice

Today, several veterinary diseases may be treated with the administration of stem cells. This is possible because these cells present a high therapeutic potential and may be injected as autologous or allogenic, freshly isolated, or previously cultured. The literature supports that the process is safe and brings considerable benefits to animal health. Knowledge about how adult stem cells modulate the molecular signals to activate cell homing has also been increasingly determined, evidencing the mechanisms which enable cells to repair and regenerate injured tissues. Preclinical studies were designed for many animal models and they have contributed to the translation to the human clinic. This review shows the most commonly used stem cell types, with emphasis on mesenchymal stem cells and their mechanistic potential to repair, as well as the experimental protocols, studied diseases, and species with the highest amount of studies and applications. The relationship between stem cell protocols utilized on clinics, molecular mechanisms, and the physiological responses may offer subsidies to new studies and therefore improve the therapeutic outcome for both humans and animals.