Isolation of pig bone marrow mesenchymal stem cells suitable for one-step procedures in chondrogenic regeneration

The role of anthrax toxin protein receptor 1 as a new mechanosensor molecule and its mechanotransduction in BMSCs under hydrostatic pressure

Anthrax toxin protein receptor (ANTXR) 1 has many similarities to integrin and is regarded in some respects as a single-stranded integrin protein. However, it is not clear whether ANTXR1 responds to mechanical signals secondary to the activation of integrins or whether it is a completely new, independent and previously undiscovered mechanosensor that responds to an undefined subset of mechanical signaling molecules. Our study demonstrates that ANTXR1 is a novel mechanosensor on the cell membrane, acting independently from the classical mechanoreceptor molecule integrinβ1. We show that bone marrow stromal cells (BMSCs) respond to the hydrostatic pressure towards chondrogenic differentiation partly through the glycogen synthase kinase (GSK) 3β/β-Catenin signaling pathway, which can be partly regulated by ANTXR1 and might be related to the direct binding between ANTXR1 and low-density lipoprotein receptor-related protein (LRP) 5/6. In addition, ANTXR1 specifically activates Smad2 and upregulates Smad4 expression to facilitate the transport of activated Smad2 to the nucleus to regulate chondrogenesis, which might be related to the direct binding between ANTXR1 and Actin/Fascin1. We also demonstrate that ANTXR1 binds to some extent with integrinβ1, but this interaction does not affect the expression and function of either protein under pressure. Thus, we conclude that ANTXR1 plays a crucial role in BMSC mechanotransduction and controls specific signaling pathways that are distinct from those of integrin to influence the chondrogenic responses of BMSCs under hydrostatic pressure.

Intravascular Stem Cell Bioreactor for Prevention of Adverse Remodeling After Myocardial Infarction

Background Prevention of adverse remodeling after myocardial infarction (MI) is an important goal of stem cell therapy. Clinical trial results vary, however, and poor cell retention and survival after delivery likely limit the opportunity to exert beneficial effects. To overcome these limitations, we built an implantable intravascular bioreactor (IBR) designed to protect contained cells from washout, dilution, and immune attack while allowing sustained release of beneficial paracrine factors. Methods and Results IBRs were constructed using semipermeable membrane adhered to a clinical-grade catheter shaft. Mesenchymal stem cell (MSC) viability in and paracrine factor release from IBRs were assessed in vitro and IBR biocompatibility and immune protection confirmed in vivo. In a porcine anterior MI model, IBRs containing 25 million allogeneic MSCs (IBR-MSCs) were compared with IBRs containing media alone (IBR-Placebo; n=8 per group) with adverse remodeling assessed by magnetic resonance imaging. Four weeks after MI, IBR-MSCs had no significant change in end-diastolic volume (+0.33±4.32 mL; P=0.89), end-systolic volume (+2.14±4.13 mL; P=0.21), and left ventricular ejection fraction (-2.27±2.94; P=0.33) while IBR-Placebo had significant increases in end-diastolic volume (+10.37±3.84 mL; P=0.01) and ESV (+11.35±2.88 mL; P=0.01), and a significant decrease in left ventricular ejection fraction (-5.78±1.70; P=0.025). Eight weeks after MI, adherent pericarditis was present in 0 of 8 IBR-MSCs versus 4 of 8 IBR-Placebo (P=0.02), suggesting an anti-inflammatory effect. In a separate study, 25 million allogeneic pig MSCs directly injected in the peri-infarct zone 3 days after MI (n=6) showed no significant benefit in adverse remodeling at 4 weeks compared with IBR-MSCs. Conclusions MSCs deployed inside an implantable, removable, and potentially rechargeable bioreactor in a large animal model remain viable, are immunoprotected, and attenuate adverse remodeling 4 weeks after MI.

Comparative analysis of in vitro proliferative, migratory and pro-angiogenic potentials of bovine fetal mesenchymal stem cells derived from bone marrow and adipose tissue

Mesenchymal stem cells (MSCs) are found in virtually all tissues, where they self-renew and differentiate into multiple cell types. Cumulative data indicate that MSCs secrete paracrine factors that may play key roles in the treatment of various acute and chronic pathological conditions in diverse animal species including cattle. The aim of the present study was to compare the potentials for proliferation, migration and pro-angiogenesis of bovine fetal BM-MSCs and AT-MSCs under in vitro conditions. Growth curves and population doubling time (PDT) were determined for BM-MSCs and AT-MSCs in order to compare in vitro cell proliferation potentials. The ability of BM-MSCs and AT-MSCs to migrate was evaluated by scratch plate and transwell migration assays. The pro-angiogenic potential of conditioned medium from BM-MSCs and AT-MSCs was compared using an endothelial cell (EC) tubule formation assay. BM-MSCs displayed higher proliferation curves and doubled their populations in fewer days compared to AT-MSCs. No significant differences were detected in the number of migrant cells between BM-MSCs and AT-MSCs; however, a higher migration value was detected for BM-MSCs compared to fibroblasts (FBs), and a higher number of migrant cells were attracted by DMEM supplemented with 5% fetal bovine serum (FBS) compared to stromal cell-derived factor-1 (SDF-1). More tubules of ECs were formed after exposure to concentrated conditioned medium from AT-MSCs compared to BM-MSCs, FBs or DMEM controls. Despite common mesodermal origin, BM-MSCs display higher proliferative capacity and lower pro-angiogenic potential compared to AT-MSCs; however, both cell types possess similar migratory ability.

Mesenchymal Stem Cell Preparation and Transfection-free Ferumoxytol Labeling for MRI Cell Tracking

Mesenchymal stem cells (MSCs) are multipotent cells and are the most widely studied cell type for stem cell therapies. In vivo cell tracking of MSCs labeled with an FDA-approved superparamagnetic iron-oxide (SPIO) particle by magnetic resonance imaging (MRI) provides essential information, e.g., MSC engraftment, survival, and fate, thus improving cell therapy accuracy. However, current methodology for labeling MSCs with Ferumoxytol (Feraheme^® ), the only FDA-approved SPIO particle, needs transfection agents. This unit describes a new "bio-mimicry" protocol to prepare more native MSCs by using more "in vivo environment" of MSCs, so that the phagocytic activity of cultured MSCs is restored and expanded MSCs can be labeled with Ferumoxytol, without the need for transfection agents and/or electroporation. Moreover, MSCs re-size to a more native size, reducing from 32.0 to 19.5 μm. The MSCs prepared from this protocol retain more native properties and would be useful for biomedical applications and MSC-tracking studies by MRI. © 2017 by John Wiley & Sons, Inc.

Development of a simple procedure for the treatment of femoral head osteonecrosis with intra-osseous injection of bone marrow mesenchymal stromal cells: study of their biodistribution in the early time points after injection

Introduction

Osteonecrosis of the femoral head (ONFH) is a degenerative disease progressing to a femoral head (FH) collapse. Injection of osteoprogenitor cells like bone marrow mesenchymal stromal cells (BMSCs) into the FH appears to be a good therapeutic treatment. However, safety and efficacy of BMSCs to treat bone defect are the main preclinical data required for clinical application. Efficacy and the lack of risk of cell transformation after amplification of BMSCs have been extensively described. The main objectives of this study were to develop a simple and usable procedure for clinicians and control its feasibility by evaluating the biodistribution of BMSCs after injection into the FH in a large animal model. The impact of this approach was evaluated on one natural pig ONFH.

Methods

BMSCs were directly injected in the pig FH, and then the biodistribution of grafted cells was detected by quantitative real-time polymerase chain reaction, cytometry, or a combination of classic histology analysis and in situ hybridization (ISH). BMSC efficacy on bone regeneration was evaluated by magnetic resonance imaging (MRI) and histology.

Results

After 30-minute and 24-hour follow-up, grafted cells were detected at the injection site and no BMSCs were detected in filter organs or body fluids. The combination of classic histology analysis and ISH showed a good homogeneity of cell distribution in FH. Local delivery of BMSCs onto a bone scaffold associated with bone formation in vivo confirmed the preferential tropism of BMSCs to the bone tissue as well as their efficacy to form bone. Treatment of a natural pig ONFH by autologous BMSCs indicated a beginning of bone healing as early as 2 weeks with a complete healing after 9 weeks. At this stage, MRI and histological analysis were similar to those of a normal FH.

Conclusions

Intra-osseous injection of BMSCs in FH seems to be a good strategy for ONFH treatment as the safety concerning the biodistribution of BMSCs is ensured. Moreover, the efficacy of BMSCs in natural ONFH seems to indicate that this is a promising approach. Altogether, these results constitute the preclinical data necessary for the setup of a clinical application with expanded BMSCs in the context of advanced therapy medicinal products.

The Chondrogenic Induction Potential for Bone Marrow-Derived Stem Cells between Autologous Platelet-Rich Plasma and Common Chondrogenic Induction Agents: A Preliminary Comparative Study

The interests in platelet-rich plasma (PRP) and their application in stem cell therapy have contributed to a better understanding of the basic biology of the prochondrogenesis effect on bone marrow-derived stem cells (BMSCs). We aimed at comparing the effect of autologous PRP with common chondrogenic induction agents (CCIAs) on the chondrogenic differentiation of BMSCs. Rabbit BMSCs were isolated and characterized by flow cytometry and differentiated towards adipocytes and osteoblasts. The chondrogenic response of BMSCs to autologous PRP and CCIAs which included transforming growth factor-β1 (TGF-β1), dexamethasone (DEX), and vitamin C (Vc) was examined by cell pellet culture. The isolated BMSCs after two passages highly expressed CD29 and CD44 but minimally expressed CD45. The osteogenic and adipogenic differentiation potentials of the isolated BMSCs were also confirmed. Compared with common CCIAs, autologous PRP significantly upregulated the chondrogenic related gene expression, including Col-2, AGC, and Sox-9. Osteogenic related gene expression, including Col-1 and OCN, was not of statistical significance between these two groups. Thus, our data shows that, compared with common chondrogenic induction agents, autologous PRP can be more effective in promoting the chondrogenesis of BMSCs.

Regeneration of the anterior cruciate ligament: Current strategies in tissue engineering

Recent advancements in the field of musculoskeletal tissue engineering have raised an increasing interest in the regeneration of the anterior cruciate ligament (ACL). It is the aim of this article to review the current research efforts and highlight promising tissue engineering strategies. The four main components of tissue engineering also apply in several ACL regeneration research efforts. Scaffolds from biological materials, biodegradable polymers and composite materials are used. The main cell sources are mesenchymal stem cells and ACL fibroblasts. In addition, growth factors and mechanical stimuli are applied. So far, the regenerated ACL constructs have been tested in a few animal studies and the results are encouraging. The different strategies, from in vitro ACL regeneration in bioreactor systems to bio-enhanced repair and regeneration, are under constant development. We expect considerable progress in the near future that will result in a realistic option for ACL surgery soon.

In vitro development of porcine transgenic nuclear-transferred embryos derived from newborn Guangxi Bama mini-pig kidney fibroblasts

Porcine transgenic cloning has potential applications for improving production traits and for biomedical research purposes. To produce a transgenic clone, kidney fibroblasts from a newborn Guangxi Bama mini-pig were isolated, cultured, and then transfected with red and green fluorescent protein genes using lipofectamine for nuclear transfer. The results of the present study show that the kidney fibroblasts exhibited excellent proliferative capacity and clone-like morphology, and were adequate for generation of somatic cell nuclear transfer (SCNT)-derived embryos, which was confirmed by their cleavage activity and blastocyst formation rate of 70.3% and 7.9%, respectively. Cells transfected with red fluorescent protein genes could be passed more than 35 times. Transgenic embryos cloned with fluorescent or blind enucleation methods were not significantly different with respect to cleavage rates (92.5% vs. 86.8%, p > 0.05) and blastocyst-morula rates (26.9% vs. 34.0%, p > 0.05), but were significantly different with respect to blastocyst rates (3.0% vs. 13.2%, p < 0.05). Cleavage (75.3%, 78.5% vs. 78.0%, p > 0.05), blastocyst (14.1%, 16.1% vs. 23.1%, p > 0.05) and morula/blastocyst rates (43.5%, 47.0% vs. 57.6%, p > 0.05) were not significantly different between the groups of transgenic cloned embryos, cloned embryos, and parthenogenetic embryos. This indicates that long-time screening by G418 caused no significant damage to kidney fibroblasts. Thus, kidney fibroblasts represent a promising new source for transgenic SCNT, and this work lays the foundation for the production of genetically transformed cloned Guangxi Bama mini-pigs.

Effect of bone marrow mesenchymal stem cell transplantation on expression of Caspase1 and IL-18 in rats with acute hepatic liver failure

AIM: To investigate the effect of bone marrow mesenchymal stem cell (BMSC) transplantation in the treatment of acute liver failure (ALF) in rats and optimize the administration route.

METHODS: D-galactosamine (D-GalN)/lipopolysaccharide (LPS) were used to make a rat model of experimental ALF. Seventy-two rats were randomly divided into an ALF group, a tail vein group, and a portal vein transplantation group. At different time points (24, 72, 120, and 168 h) after BMSC transplantation, serum ALT and AST were detected. TUNEL assay was applied to detect hepatocyte apoptosis. Immunohistochemistry and Western blot were performed to detect the expression of Caspase1 and IL-18 proteins in liver tissue.

RESULTS: Serum levels of ALT and AST in the ALF group were gradually increased with the progression of the disease. Compared with the ALF group, significant improvement of liver function parameters and histological findings was observed in the transplantation group 120 and 168 h after transplantation (P < 0.05 for both). The apoptosis indexes in the tail vein group and portal vein transplantation group (120 h: 28.17% ± 17.08%, 20.67% ± 12.68%; 168 h: 19.67 % ± 11.82%, 13.00 % ± 6.84% ) were significantly lower than those in the ALF group (P < 0.01 for all). The expression levels of Caspase1 and IL-18 proteins in the two transplantation groups were decreased significantly at 120 and 168 h compared with the ALF group (P < 0.05 for both). Both administration routes had a therapeutic effect against ALF in rats, but no significant difference was observed between them.

CONCLUSION: BMSCs can improve the liver function, inhibit hepatic apoptosis and reduce the levels of Caspase1 and IL-18 proteins in ALF rats. Caspase1 and IL-18 play an important role in the pathogenesis of ALF and are expected to be predictors of ALF and future therapeutic targets.

Comparisons of rabbit bone marrow mesenchymal stem cell isolation and culture methods in vitro

Bone marrow mesenchymal stem cells (BMSCs) have great potential in tissue engineering and clinical therapy, and various methods for isolation and cultivation of BMSCs have been reported. However, the best techniques are still uncertain. Therefore, we sought the most suitable among the four most common methods for BMSC separation from rabbits. BMSCs were obtained from untreated whole bone marrow (BM) adherent cultures, 3 volumes of red blood cells (RBC) lysed with ammonium chloride, 6 volumes of RBC lysed with ammonium chloride, and Ficoll density gradient centrifugation. Then, isolated BMSCs were evaluated with respect to primary cell yield, number of CFU-F colonies, proliferative capacity, cell phenotype, and chondrogenic differentiation potential. Our data show that BMSCs were successfully isolated by all four methods, and each method was similar with regard to cell morphology, phenotype, and differentiation potential. However, BMSCs from untreated whole BM adherent cultures had greater primary cell yields, larger colonies, and the shortest primary culture time (P<0.05). Moreover, the 4^th generation of cultured cells had the strongest proliferative activity, the fastest growth rate and the most numerous cells compared with other cell passage generations (P<0.05). In conclusion, untreated whole BM adherent cultures are best for rabbit BMSC isolation and the 4^th generation of cells has the strongest proliferation capacity.

A two-step method of constructing mature cartilage using bone marrow-derived mesenchymal stem cells

Bone marrow-derived mesenchymal stem cells (BMSCs) are a promising source of stem cells for tissue engineering in cartilage repair. However, construction of cartilage using BMSCs can involve many problems, such as fibrosis, vascularization, the 'hollow' phenomenon and shrinkage, which may be caused by the incomplete differentiation of BMSCs and prevent the clinical application of tissue-engineered cartilage. A novel induction system that facilitates chondrogenesis by swine BMSCs has been developed. In this study, we constructed cartilage using a two-step procedure: first, promoting complete chondrogenic differentiation of BMSCs in 8 weeks, and second, these chondrocytes which differentiated from BMSCs in vitro were provided with a three-dimensional scaffold, which was then implanted subcutaneously. The results indicate that this two-step construction procedure can promote the full chondrogenic differentiation of BMSCs in vitro and the formation of mature ectopic cartilage by BMSCs in vivo.

Intraoperative stem cell therapy

Stem cells hold significant promise for regeneration of tissue defects and disease-modifying therapies. Although numerous promising stem cell approaches are advancing in clinical trials, intraoperative stem cell therapies offer more immediate hope by integrating an autologous cell source with a well-established surgical intervention in a single procedure. Herein, the major developments in intraoperative stem cell approaches, from in vivo models to clinical studies, are reviewed, and the potential regenerative mechanisms and the roles of different cell populations in the regeneration process are discussed. Although intraoperative stem cell therapies have been shown to be safe and effective for several indications, there are still critical challenges to be tackled prior to adoption into the standard surgical armamentarium.

Cell-free repair of small cartilage defects in the Goettinger minipig: which defect size is possible?

PURPOSE

Cartilage repair of full-thickness chondral defects in the knees of Goettinger minipigs was assessed by treatment with cell-free collagen type-I gel plugs of three different sizes.

METHODS

In 6 adult Goettinger minipigs, three full-thickness chondral defects were created in the trochlear groove of one knee of the hind leg. These defects were treated with a cell-free collagen type-I gel plug of 8, 10, or 12 mm diameter. All animals were allowed unlimited weight bearing. After 1 year, the animals were killed. Immediately after recovery, a non-destructive biomechanical testing was performed. The repair tissue quality was evaluated immunohistologically, collagen type-II protein was quantified, and a semiquantitative score (O'Driscoll score) was calculated.

RESULTS

After 1 year, a high number of cells migrated into the initially cell-free collagen gel plugs and a hyaline-like repair tissue had been created. The O'Driscoll scores were: 8 mm, 21.2 (SD, 2.8); 10 mm, 21.5 (SD, 1.6); and 12 mm, 22.3 (SD, 1.0). The determination of the e-modulus, creep and relaxation revealed that mechanical properties of the two smaller defects were closer to unaffected hyaline cartilage.

CONCLUSIONS

As cell-free collagen type-I gel plugs of all three different sizes created hyaline-like repair tissue, this system seems suitable for the treatment of even larger defects.