Long bone mesenchymal stem cells (Lb-MSCs): clinically reliable cells for osteo-diseases

Enhanced growth and differentiation of neural stem cells on alginate/collagen/reduced graphene oxide composite hydrogel incorporated with lithium chloride

Introduction

Cell transplantation with hydrogel-based carriers is one of the advanced therapeutics for challenging diseases, such as spinal cord injury. Electrically conductive hydrogel has received much attention for its effect on nerve outgrowth and differentiation. Besides, a load of neuroprotective substances, such as lithium chloride can promote the differentiation properties of the hydrogel.

Methods

In this study, alginate/collagen/reduced graphene oxide hydrogel loaded with lithium chloride (AL/CO/rGO Li+) was prepared as an injectable cell delivery system for neural tissue regeneration. After determining the lithium-ion release profile, an MTT assay was performed to check neural viability. In the next step, real-time PCR was performed to evaluate the expression of cell adhesion and neurogenic markers.

Results

Our results showed that the combination of collagen fibers and rGO with alginates increased cell viability and the gene expression of collagen-binding receptor subunits such as integrin α1, and β1. Further, rGO contributed to the controlled release of lithium-ion hydrogel in terms of its plenty of negatively charged functional groups. The continuous culture of NSCs on AL/CO/rGO Li+ hydrogel increased neurogenic genes' expressions of nestin (5.9 fold), NF200 (36.8 fold), and synaptophysin (13.2 fold), as well as protein expression of NF200 and synaptophysin after about 14 days.

Conclusion

The simultaneous ability of electrical conduction and lithium-ion release of AL/CO/rGO Li+ hydrogel could provide a favorable microenvironment for NSCs by improving their survival, maintaining cell morphology, and expressing the neural marker. It may be potentially used as a therapeutic approach for stem cell transplantation in a spinal cord injury.

Gene Therapy for Regenerative Medicine

The development of biological methods over the past decade has stimulated great interest in the possibility to regenerate human tissues. Advances in stem cell research, gene therapy, and tissue engineering have accelerated the technology in tissue and organ regeneration. However, despite significant progress in this area, there are still several technical issues that must be addressed, especially in the clinical use of gene therapy. The aims of gene therapy include utilising cells to produce a suitable protein, silencing over-producing proteins, and genetically modifying and repairing cell functions that may affect disease conditions. While most current gene therapy clinical trials are based on cell- and viral-mediated approaches, non-viral gene transfection agents are emerging as potentially safe and effective in the treatment of a wide variety of genetic and acquired diseases. Gene therapy based on viral vectors may induce pathogenicity and immunogenicity. Therefore, significant efforts are being invested in non-viral vectors to enhance their efficiency to a level comparable to the viral vector. Non-viral technologies consist of plasmid-based expression systems containing a gene encoding, a therapeutic protein, and synthetic gene delivery systems. One possible approach to enhance non-viral vector ability or to be an alternative to viral vectors would be to use tissue engineering technology for regenerative medicine therapy. This review provides a critical view of gene therapy with a major focus on the development of regenerative medicine technologies to control the in vivo location and function of administered genes.

Bioactive glass-collagen/poly (glycolic acid) scaffold nanoparticles exhibit improved biological properties and enhance osteogenic lineage differentiation of mesenchymal stem cells

Today’s using tissue engineering and suitable scaffolds have got attention to increase healing of non-union bone fractures. In this study, we aimed to prepare and characterize scaffolds with functional and mechanical properties suitable for bone regeneration. Porous scaffolds containing collagen-poly glycolic acid (PGA) blends and various quantities of bioactive glass (BG) 45S5 were fabricated. Scaffolds with different compositions (BG/collagen-PGA ratios (w/w): 0/100; 40/60; 70/30) were characterized for their morphological properties, bioactivity, and mechanical behavior. Then, biocompatibility and osteogenic differentiation potential of the scaffolds were analyzed by seeding mesenchymal stem cells (MSCs). Scaffolds made with collagen-PGA combined with the BG (45S5) were found to have interconnected pores (average pore diameter size 75–115 µm) depending on the percentage of the BG added. Simulated body fluid (SBF) soaking experiments indicated the stability of scaffolds in SBF regardless of their compositions, while the scaffolds retained their highly interconnected structure. The elastic moduli, cell viability, osteogenic differentiation of the BG/collagen-PGA 40/60 and 70/30 scaffolds were superior to the original BG/collagen-PGA (0/100). These results suggest that BG incorporation enhanced the physical stability of our collagen-PGA scaffold previously reported. This new scaffold composition provides a promising platform to be used as a non-toxic scaffold for bone regeneration and tissue engineering.

Cartilage tissue engineering by co-transplantation of chondrocyte extracellular vesicles and mesenchymal stem cells, entrapped in chitosan-hyaluronic acid hydrogel

Mesenchymal stem cells (MSCs) on injectable hydrogels are mostly used to regenerate articular cartilage, which would have a variety of outcomes. Chondrocyte extracellular vesicles (EVs) have attracted many attentions for their chondrogenic differentiation capacity; however, the roles of EVs in both chondrogenic differentiation of MSCs and cartilage regeneration are poorly understood yet. In the current study, to investigate the differentiation effects of human articular chondrocyte EVs on adipose-derived MSCs, they were cultured in injectable chitosan-hyaluronic acid (CS-HA) hydrogel and then treated with chondrocyte EVs for 21 days. The continuous treatment of EVs performed on MSCs increased chondrogenic genes' expressions ofSOX9andCOL2A1and induced expression of Col II protein. In addition, glycosaminoglycans secretion was detected in the EV-treated MSCs after about 14 days. The therapeutic efficiency of this hydrogel and EVs was studied in a rabbit osteochondral defect model. MRI results revealed that the cartilage regeneration capacity of EV-treated MSCs with CS-HA hydrogel was greater than the untreated MSCs or the EV-treated MSCs without hydrogel. Moreover, histological results showed hyaline-like cartilage in the CS-HA/MSC and CS-HA/EV/MSC groups in the cartilage defect sites. These findings suggested that the chondrocyte-EVs and CS-HA hydrogel could provide the preferable niche for chondrogenic differentiation of MSCs and cartilage regeneration in osteoarthritis cartilage injuries.

CRISPR/Cas9 mediated GFP-human dentin matrix protein 1 (DMP1) promoter knock-in at the ROSA26 locus in mesenchymal stem cell for monitoring osteoblast differentiation

BACKGROUND

Dentin matrix protein 1 (DMP1) is highly expressed in mineralized tooth and bone, playing a critical role in mineralization and phosphate metabolism. One important role for the expression of DMP1 in the nucleus of preosteoblasts is the up-regulation of osteoblast-specific genes such as osteocalcin and alkaline phosphatase¹ . The present study aimed to investigate the potential application of human DMP1 promoter as an indicator marker of osteoblastic differentiation.

METHODS

In the present study, we developed DMP1 promoter-DsRed-GFP knock-in mesenchymal stem cell (MSCs) via the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system that enabled automatic detection of osteoblast differentiation. With the application of a homology-directed knock-in strategy, a 2-kb fragment of DMP1 promoter, which was inserted upstream of the GFP and DsRed reporter cassette, was integrated into the human ROSA locus to generate double fluorescent cells. We further differentiated MSCs under osteogenic media to monitor the fate of MSCs. First, cells were transfected using CRISPR/Cas9 plasmids, which culminated in MSCs with a green fluorescence intensity, then GFP-positive cells were selected using puromycin. Second, the GFP-positive MSCs were differentiated toward osteoblasts, which demonstrated an increased red fluorescence intensity. The osteoblast differentiation of MSCs was also verified by performing alkaline phosphatase and Alizarin Red assays.

RESULTS

We have exploited the DMP1 promoter as a predictive marker of MSC differentiation toward osteoblasts. Using the CRISPR/Cas9 technology, we have identified a distinctive change in the fluorescence intensities of GFP knock-in (green) and osteoblast differentiated MSCs ² .

CONCLUSIONS

The data show that DMP1-DsRed-GFP knock-in MSCs through CRISPR/Cas9 technology provide a valuable indicator for osteoblast differentiation. Moreover, The DMP1 promoter might be used as a predictive marker of MSCs differentiated toward osteoblasts.

Treatment with Cinacalcet in Hemodialysis Patients with Severe Secondary Hyperparathyroidism, Influences Bone Mineral Metabolism and Anemia Parameters

Background:

Due to the premium rate of Chronic Kidney Disease, we have increased our knowledge with respect to diagnosis and treatment of Bone Mineral Disease (BMD) in End- Stage Renal Disease (ESRD). Currently, various treatment options are available. The medication used for Secondary Hyper-Parathyroidism gives promising results in the regulation of Ca, P and Parathormone levels, improving the quality of life. The aim of the present study was to investigate the relation of cinacalcet administration to not only parathormone, Ca and P but also to anemia parameters such as hematocrit and hemoglobin.

Materials and Methods:

retrospective observational study was conducted in a Chronic Hemodialysis Unit. One-hundred ESRD patients were recruited for twenty-four months and were evaluated on a monthly rate. Biochemical parameters were related to medication prescribed and the prognostic value was estimated. Cinacalcet was administered to 43 out of 100 patients in a dose of 30-120 mg.

Results:

Significant differences were observed in PTH, Ca and P levels with respect to Cinacalcet administration. Ca levels appeared to be higher at 30mg as compared to 60mg cinacalcet. Furthermore, a decreasing age-dependent pattern was observed with respect to cinacalcet dosage. A positive correlation was observed between Dry Weight (DW) and cinacalcet dose. Finally, a positive correlation between Hematocrit and Hemoglobin and cinacalcet was manifested.

Conclusions:

Cinacalcet, is a potential cardiovascular and bone protective agent, which is approved for use in ESRD patients to assist SHPT. A novel information was obtained from this study, regarding the improvement of the control of anemia.

Comparison the effects of hypoxia-mimicking agents on migration-related signaling pathways in mesenchymal stem cells

Adipose-derived mesenchymal stem cells (Ad-MSCs) have been designated as the promising agents for clinical applications for easy accessibility, multi-linage differentiation and immunomodulation capacity. Despite this, optimal cell delivery conditions have remained as a clinical challenge and improvement of stem cell homing to the target organs is being considered as a major strategy in cell therapy systemic injection. It has been shown that homing of mesenchymal stem cells are increased when treated with physical or chemical hypoxia-mimicking factors, however, efficiency of different agents remained to be determined. In this study, hypoxia-mimicking agents, including valproic acid (VPA), cobalt chloride (CoCl₂) and deferoxamine (DFX) were examined to determine whether they are able to activate signaling molecules involved in migration of Ad-MSCs in vitro. We report that Ad-MSCs treated by DFX resulted in a significantly enhanced mRNA expression of MAPK4 (associated with MAPK signaling pathway), INPP4B (associated with Inositol polyphosphate pathway), VEGF-A and VEGF-C (associated with cytokine-cytokine receptor pathways), IL-8 and its receptor, CXCR2 (associated with IL-8 signaling pathway). While the cells treated with VPA did not show such effects and CoCl₂ only upregulated VEGF-A and VEGF-C gene expression. Furthermore, results of wound-healing assays showed migration capacity of Ad-MSCs treated with DFX significantly increased 8 and 24 h of the treatment. This study provides credible evidence around DFX, which might be an effective drug for pharmacological preconditioning of Ad-MSCs to boost their homing capacity and regeneration of damaged tissues though, activation of the migration-related signaling pathways.

Osteogenesis and bone remodeling: A focus on growth factors and bioactive peptides

Bone is one of the most frequently transplanted tissues. The bone structure and its physiological function and stem cells biology were known to be closely related to each other for many years. Bone is considered a home to the well-known systems of postnatal mesenchymal stem cells (MSCs). These bone resident MSCs provide a range of growth factors (GF) and cytokines to support cell growth following injury. These GFs include a group of proteins and peptides produced by different cells which are regulators of important cell functions such as division, migration, and differentiation. GF signaling controls the formation and development of the MSCs condensation and plays a critical role in regulating osteogenesis, chondrogenesis, and bone/mineral homeostasis. Thus, a combination of both MSCs and GFs receives high expectations in regenerative medicine, particularly in bone repair applications. It is known that the delivery of exogenous GFs to the non-union bone fracture site remarkably improves healing results. Here we present updated information on bone tissue engineering with a specific focus on GF characteristics and their application in cellular functions and tissue healing. Moreover, the interrelation of GFs with the damaged bone microenvironment and their mechanistic functions are discussed.

Generation of scaffold incorporated with nanobioglass encapsulated in chitosan/chondroitin sulfate complex for bone tissue engineering

Over the past decade, various composite materials fabricated using natural or synthetic biopolymers incorporated with bioceramic have been widely investigated for the regeneration of segmental bone defect. In the present study, nano-bioglass incorporated osteoconductive composite scaffolds were fabricated through polyelectrolyte complexation/phase separation and resuspension of separated complex in gelatin matrix. Developed scaffold exhibits controlled bioreactivity, minimize abrupt pH rise (~7.8), optimal swelling behavior (2.6+-3.1) and enhances mechanical strength (0.62 ± 0.18 MPa) under wet condition. Moreover, in-vitro cell study shows that the fabricated scaffold provide suitable template for cellular attachment, spreading, biomineralization and collagen based matrix deposition. Also, the developed scaffold was evaluated for biocompatibility and bone tissue regeneration potential through implantation in non-union segmental bone defect created in rabbit animal model. The obtained histological analysis indicates strong potential of the composite scaffold for bone tissue regeneration, vascularization and reconstruction of defects. Thus, the developed composite scaffold might be a suitable biomaterial for bone tissue engineering applications.

Characterization and therapeutic applications of mesenchymal stem cells for regenerative medicine

BACKGROUND

Mesenchymal stem cells (MSCs) are multipotent, genomic stable, self-renewable, and culturally expandable adult stem cells. MSCs facilitate tissue development, maintenance and repair, and produce secretory factors that support engraftment and trophic functions, marking them an attractive option in cell therapy, regenerative medicine and tissue engineering.

METHOD

In this review, we summarize the recent researches regarding the isolation and characterization of MSCs, therapeutic applications and advanced engineering techniques. We also discuss the advantages and limitations that remain to be overcome for MSCs based therapy.

RESULTS

It has been demonstrated that MSCs are able to modulate endogenous tissue and immune cells. Preclinical studies and early phase clinical trials have shown their great potential for tissue engineering of bone, cartilage, marrow stroma, muscle, fat, and other connective tissues.

CONCLUSIONS

MSC-based therapy show considerable promise to rebuild damaged or diseased tissues, which could be a promising therapeutic method for regeneration medicine.

Current progress in hepatic tissue regeneration by tissue engineering

Liver, as a vital organ, is responsible for a wide range of biological functions to maintain homeostasis and any type of damages to hepatic tissue contributes to disease progression and death. Viral infection, trauma, carcinoma, alcohol misuse and inborn errors of metabolism are common causes of liver diseases are a severe known reason for leading to end-stage liver disease or liver failure. In either way, liver transplantation is the only treatment option which is, however, hampered by the increasing scarcity of organ donor. Over the past years, considerable efforts have been directed toward liver regeneration aiming at developing new approaches and methodologies to enhance the transplantation process. These approaches include producing decellularized scaffolds from the liver organ, 3D bio-printing system, and nano-based 3D scaffolds to simulate the native liver microenvironment. The application of small molecules and micro-RNAs and genetic manipulation in favor of hepatic differentiation of distinct stem cells could also be exploited. All of these strategies will help to facilitate the application of stem cells in human medicine. This article reviews the most recent strategies to generate a high amount of mature hepatocyte-like cells and updates current knowledge on liver regenerative medicine.

Stem and progenitor cell microenvironment for bone regeneration and repair

Stem cells reside in their native microenvironment, which provides dynamic physical and chemical cues essential to their survival, proliferation and function. A typical cell-based therapeutic approach requires the mesenchymal stem cells (MSC) to depart their native microenvironment, transplant to in-vivo environment, differentiate toward multiple lineages and participate in bone formation. The long-term survival, function and fate of MSC are dependent on the microenvironment in which they are transplanted. Transplantation of morselized autologous bone, which contains both stem cells and their native microenvironment, results in a good clinical outcome. However, implantation of bone graft substitutes does not provide the complete and dynamic microenvironment for MSC. Current bone graft therapeutics may need to be improved further to provide an optimal engineered MSC microenvironment.