Gene Expression Profile of 3D Spheroids in Comparison with 2D Cell Cultures and Tissue Strains of Diffuse High-Grade Gliomas

The use of relevant, accessible, and easily reproducible preclinical models of diffuse gliomas is a prerequisite for the development of successful therapeutic approaches to their treatment. Here we studied the gene expression profile of 3D spheroids in a comparison with 2D cell cultures and tissue strains of diffuse high-grade gliomas. Using real time PCR, we evaluated the expression of Gfap, Cd44, Pten, S100b, Vegfa, Hif1a, Sox2, Melk, Gdnf, and Mgmt genes playing an important role in the progression of gliomas and regulating tumor cell proliferation, adhesion, invasion, plasticity, apoptosis, DNA repair, and recruitment of tumor-associated cells. Gene expression analysis showed that 3D spheroids are more similar to tumor tissue strains by the expression levels of Gfap, Cd44, and Pten, while the expression levels of Hif1a and Sox2 in 3D spheroids did not differ from those of 2D cell cultures, the expression levels S100b and Vegfa in 3D spheroids was higher than in other models, and the expression levels of Melk, Gdnf, and Mgmt genes changed diversely. Thus, 3D spheroid model more closely mimics the tumor tissue than 2D cell culture, but still is not the most relevant, probably due to too small size of spheroids, which does not allow reproducing hypoxia and apoptotic and necrotic processes in the tumor tissue.

Adenovirus-Based Gene Therapy for Bone Regeneration: A Comparative Analysis of In Vivo and Ex Vivo BMP2 Gene Delivery

Adenovirus-mediated gene therapy is a promising tool in bone regenerative medicine. In this work, gene-activated matrices (GAMs) composed of (1) polylactide granules (PLA), which serve as a depot for genetic constructs or matrices for cell attachment, (2) a PRP-based fibrin clot, which is a source of growth factors and a binding gel, and (3) a BMP2 gene providing osteoinductive properties were studied. The study aims to compare the effectiveness of in vivo and ex vivo gene therapy based on adenoviral constructs with the BMP2 gene, PLA particles, and a fibrin clot for bone defect healing. GAMs with Ad-BMP2 and MSC(Ad-BMP2) show osteoinductive properties both in vitro and in vivo. However, MSCs incubated with GAMs containing transduced cells showed a more significant increase in osteopontin gene expression, protein production, Alpl activity, and matrix mineralization. Implantation of the studied matrices into critical-size calvarial defects after 56 days promotes the formation of young bone. The efficiency of neoosteogenesis and the volume fraction of newly formed bone tissue are higher with PLA/PRP-MSC(Ad-BMP2) implantation (33%) than PLA/PRP-Ad-BMP2 (28%). Thus, ex vivo adenoviral gene therapy with the BMP2 gene has proven to be a more effective approach than the in vivo delivery of gene constructs for bone regeneration.

[Relative survival and cell adhesion of multipotent mesenchymal cells from primary teeth pulp on the surface membranes and sponges produced from collagen]

OBJECTIVE

To study the behavior of SHED cell culture on different types of materials for the regeneration of periodontal tissues with different porosity.

MATERIAL AND METHODS

Porous collagen material Fibro-Gide (Geitstlich Pharma AG, Switzerland), designed to increase the volume of the gum and the barrier collagen membrane Bio-Gide (Geitstlich Pharma AG, Switzerland) were studied in vitro on SHED cultures. As a control sample, a Spongostan sponge made of gelatin (Johnson & Johnson Medical, UK) with the most pronounced porosity and wettability was used. Acute cytotoxicity was determined using a screening method for assessing the number of living cells in a sample (MTT test). SHED cells were sown on the materials to study the attachment of cells to materials and their migration inside the samples. Before seeding, the cells were stained with vital fluorescent dye PKH26 (red fluorescent cell linker kit, Sigma, Germany) for further visualization.

RESULTS AND DISCUSSION

Using the MTT test it was shown that they do not have cytotoxic effects. At the same time by the 8th day of the experiment in the presence of Fibro-Gide and Bio-Gide the cells showed an increase in proliferative activity by 19% and 12%, respectively compared with the control group. The cells attached and spread out on the surface of the materials and migrated into the thickness of porous Fibro-Gide and Spongostan.

CONCLUSION

The in vitro study showed that the most favorable material for SHED cell culture is the collagen material Fibro-Gide with sufficient porosity, elasticity and hydrophilicity. SHED cells attach to the collagen matrix and easily penetrate into the sample, filling the entire internal space, while the proliferative capacity of the cell culture increases.

[Advantages and disadvantages of bone graft materials activated by BMP-2 and constructs carrying its gene]

In the review gene constructs and proteins used to impart osteoinductive properties to bone graft materials are compared. On the basis of clinical and experimental data the experience and prospects of their application in maxillofacial surgery and dentistry are described. Information about complications associated with the use of bone morphogenetic protein-2 (BMP-2) and vectors carrying its gene is provided.

Comparative Efficiency of Gene-Activated Matrices Based on Chitosan Hydrogel and PRP Impregnated with BMP2 Polyplexes for Bone Regeneration

Gene therapy is one of the most promising approaches in regenerative medicine. Gene-activated matrices provide stable gene expression and the production of osteogenic proteins in situ to stimulate osteogenesis and bone repair. In this study, we developed new gene-activated matrices based on polylactide granules (PLA) impregnated with BMP2 polyplexes and included in chitosan hydrogel or PRP-based fibrin hydrogel. The matrices showed high biocompatibility both in vitro with mesenchymal stem cells and in vivo when implanted intramuscularly in rats. The use of porous PLA granules allowed the inclusion of a high concentration of polyplexes, and the introduction of the granules into hydrogel provided the gradual release of the plasmid constructs. All gene-activated matrices showed transfecting ability and ensured long-term gene expression and the production of target proteins in vitro. At the same time, the achieved concentration of BMP-2 was sufficient to induce osteogenic differentiation of MSCs. When implanted into critical-size calvarial defects in rats, all matrices with BMP2 polyplexes led to new bone formation. The most significant effect on osteoinduction was observed for the PLA/PRP matrices. Thus, the developed gene-activated matrices were shown to be safe and effective osteoplastic materials. PLA granules and PRP-based fibrin hydrogel containing BMP2 polyplexes were shown to be the most promising for future applications in bone regeneration.

Osteoinductive Moldable and Curable Bone Substitutes Based on Collagen, BMP-2 and Highly Porous Polylactide Granules, or a Mix of HAP/β-TCP

In dentistry, maxillofacial surgery, traumatology, and orthopedics, there is a need to use osteoplastic materials that have not only osteoinductive and osteoconductive properties but are also convenient for use. In the study, compositions based on collagen hydrogel were developed. Polylactide granules (PLA) or a traditional bone graft, a mixture of hydroxyapatite and β-tricalcium phosphate (HAP/β-TCP), were used for gel filling to improve mechanical osteoconductive properties of compositions. The mechanical tests showed that collagen hydrogels filled with 12 wt% highly porous PLA granules (elastic modulus 373 ± 55 kPa) or 35 wt% HAP/β-TCP granules (elastic modulus 451 ± 32 kPa) had optimal manipulative properties. All composite components were cytocompatible. The cell’s viability was above 90%, and the components’ structure facilitated the cell’s surface adhesion. The bone morphogenetic protein-2 (BMP-2) provided osteoinductive composition properties. It was impregnated directly into the collagen hydrogel with the addition of fibronectin or inside porous PLA granules. The implantation of a collagen hydrogel with BMP-2 and PLA granules into a critical-size calvarial defect in rats led to the formation of the most significant volume of bone tissue: 61 ± 15%. It was almost 2.5 times more than in the groups where a collagen-fibronectin hydrogel with a mixture of HAP/β-TCP (25 ± 7%) or a fibronectin-free composition with porous PLA granules impregnated with BMP-2 (23 ± 8%) were used. Subcutaneous implantation of the compositions also showed their high biocompatibility and osteogenic potential in the absence of a bone environment. Thus, the collagen-fibronectin hydrogel with BMP-2 and PLA granules has optimal biocompatibility, osteogenic, and manipulative properties.

Development prospects of curable osteoplastic materials in dentistry and maxillofacial surgery

The article presents classification of the thermosetting materials for bone augmentation. The physical, mechanical, biological, and clinical properties of such materials are reviewed. There are two main types of curable osteoplastic materials: bone cements and hydrogels. Compared to hydrogels, bone cements have high strength features, but their biological properties are not ideal and must be improved. Hydrogels are biocompatible and closely mimic the extracellular matrix. They can be used as cytocompatible scaffolds for tissue engineering, as can protein- and nucleic acid-activated structures. Hydrogels may be impregnated with osteoinductors such as proteins and genetic vectors without conformational changes. However, the mechanical properties of hydrogels limit their use for load-bearing bone defects. Thus, improving the strength properties of hydrogels is one of the possible strategies to achieve the basis for an ideal osteoplastic material.

Analysis of the Expression of Regulator Genes in Kupffer Cells and Monocytes

Differences in the gene expression profiles in resident macrophages (in particular, Kupffer cells) and monocytes were revealed. However, these differences in gene expression profiles do not allow considering resident liver macrophages as purely M2 macrophages and monocytes as purely M1 macrophages. At the same time, a significant number of the genes upregulated in Kupffer cells are associated with normal regulation of liver functions (Arg 1, Flt, iNOs, and Kng). In monocytes, the expression of genes Alox15, Alox12, Tlr2, Tlr4, Tlr7, and Tlr8 (typical functional genes of macrophages) was also upregulated in comparison with Kupffer cells.

[Chitosan hydrogels biocompatibility improvement with the perspective of use as a base for osteoplastic materials in dentistry]

Using chitosan as the basis for osteoplastic material, we were dealt with its low biocompatibility. The critical assessment of it is poorly presented in the literature and does not have systematic approaches to solving. The aim of the study was to determine the effect of factors affecting chitosan charge and its free amino groups number on the biocompatibility of hydrogels. Biocompatibility of chitosan compositions were studied in male Wistar rats (n=90). The subcutaneous implantation of chitosan discs and hydrogel caused abundant leukocyte infiltration. The addition of β-glycerophosphate followed by dialysis slightly reduced the inflammatory response. Treatment with a solution of alkali NaOH and NaHCO3 buffer, on the contrary, intensified the inflammatory response. It is confirmed the effect of charged amino groups of chitosan on leukocyte taxis A decrease in the deacetylation degree (DD) of chitosan to 39.0% led to a statistically significant decrease in leukocyte infiltration. Saturation of chitosan hydrogels with PLA granules reduced by 16% the level of leukocyte infiltration, which was supposedly associated with a decrease in the volume of the hydrogel and an increase in the area of its interaction with blood plasma proteins, which reduce the positive charge of chitosan. The most significant reduction in leukocyte infiltration was achieved with a combination of deacetylated to 39.0% chitosan hydrogel with the addition of 16% by weight highly porous PLA granules.

[Safety and efficacy of BMP-2 and BMP-7 use in dentistry]

The article deals with bone morphogenetic proteins BMP-2 and BMP-7 with high osteoinductive potential. The materials containing these proteins are considered. Their safety and efficacy for regeneration of maxillofacial bone defects are evaluated. The prospects of bone tissue regeneration technologies development based on the use of bone morphogenetic proteins are described.

[The prospects of collagen as a basis for curable and activated osteoplastic materials]

In the review, the structure and biological properties of collagen, variants of its production from natural sources and purification are considered. Methods for modifying the physico-mechanical properties of collagen to create a curable, highly purified collagen hydrogel are described. The advantages of a cured highly purified collagen hydrogel as a basis for osteoplastic material and a means of delivery of growth factors are indicated. The registered osteoplastic materials based on the curable highly purified collagen hydrogel are described, and their comparative analysis is carried out. On the basis of the obtained data, a conclusion was made about the prospects of using collagen as a basis for curable and activated osteoplastic materials.

[Regeneration of dental pulp tissue using pulpal autologous mesenchymal stem cells and platelet-rich plasma]

Regeneration of pulp and dentin could be important in operative dentistry as a method to save teeth. Currently cell population from dental pulp of deciduous and permanent teeth of humans and laboratory animals are isolated and characterized. The paper presents a study on pulp regeneration using autologous mesenchymal stromal cells from pulp of molars in combination with fibrin clot, transplanted in pulp chamber of miniature pigs after pulp removal. The results proved that transplantation of autologous multipotent stromal cells of dental pulp in combination with autologous platelet-rich plasma in pulp chamber of miniature pigs after pulp removal leads to pulp restoration and reparative dentinogenesis with dentinal bridge formation on the 30th day. However, the completion of regeneration also results in a decrease in the pulp chamber volume due to the neodentin bedding. Tissue regeneration of dental pulp by direct pulp capping in the absence of inflammatory processes is a promising direction of the use of cellular technologies.

[The prospects of hydrogels usage as a basis for curable osteoplastic materials]

The article deals with the main types of the polymers used in hydrogel preparation. Their biological, physical and chemical properties was compared. Ways of polymers hardening and prospects of medical application were considered. The prospect of use of chitosan hydrogels activated by osteoinductors as a material for bone augmentation were concluded.

Effect of Endothelial Cells on Angiogenic Properties of Multipotent Stromal Cells from the Umbilical Cord during Angiogenesis Modeling in the Basement Membrane Matrix

Short-term cell culturing on basement membrane matrix is a common and very convenient in vitro model of angiogenesis. We studied the possibility of interaction of multipotent stromal cells from the umbilical cord and Ea.hy926 endothelial cells on this model at the early and late periods of the experiment. Multipotent stromal cells alone and in combination with endothelial cells formed an unstable tubular network. Clusters formed after its disassembling later became the sprouting centers in co-culture of the two cell types, but not in pure culture of multipotent stromal cells. Multipotent stromal cells with CD31+ phenotype constitute the structural basis of newly formed stable 3D capillary-like network. Prolongation of the time of culturing and combination of the two in vitro models of angiogenesis (tubulogenesis and sprouting) allowed more complete assessment of the angiogenic potential of multipotent stromal cells.

Mechanisms of therapeutic activity of multipotent cells in heart diseases

Analysis of our findings and published reports on possible mechanisms of therapeutic activity of stem/progenitor cell transplantation in cardiovascular pathologies is presented.

Isolation of insulin-producing cells from different populations of multipotent stromal cells of the umbilical cord and human adipose tissue

Stromal cells of adipose tissue and human umbilical cord were isolated by the original method from general populations of multipotent subpopulation of multipotent stromal cells exhibiting perivascular phenotype (CD146+, CD31-). Effective directed differentiation of these cells into insulin-producing cells by transient transfection of the gene Pdx1 was demonstrated. Transfection multipotent stromal cells CD146-, CD31- derived from adipose tissue and umbilical cord and isolated by the standard method, did not result in activation of insulin gene transcription. It was shown that the expression of nestin was not necessary for effective pancreatic cell differentiation.

Study of the safety of transplantation of cultured autologous human chondroblasts

Study of tumorigenic activity of cultured human chondroblasts intended for autologous transplantations showed that subcutaneous injection of human chondroblast suspension in a dose of 10(7)cells/0.2 ml did not cause the development of tumors in C.B-17 SCID immunodeficient mice over 12 weeks. Subcutaneous formations of compact cartilaginous consistency persisted at the site of chondroblast transplantation in all animals; these formations gradually shrank. Subcutaneous injection of tumor cell suspension (A204 human embryonic sarcoma) to C.B-17 SCID mice under the same conditions caused 100% development of tumors (poorly differentiated sarcomas) by day 14.

Clinical study of the efficiency of combined cell transplant on the basis of multipotent mesenchymal stromal adipose tissue cells in patients with pronounced deficit of the maxillary and mandibulary bone tissue

The use of synthetic osteoplastic materials not always provides the required amount of the bone tissue. Transplantation of tissue-engineering constructs containing osteogenic precursor cells can be an alternative high-technology implantation method. Here we present the results of a pilot clinical study demonstrating safety of this method, accelerated healing of the operation wound, formation of young bone tissue after transplantation, and the possibility of mounting implants after 3 months in case of sufficient amount of the bone for primary fixation.

Whether modern cell technologies can break down biological limitations of tissue-specific regeneration of the myocardium

The paper reviews modern concepts of physiological and reparative regeneration of the myocardium as a highly specific and highly differentiated tissue system. Special attention was given to evaluation of the proliferative potential of cardiomyocytes, in particular, to the existence of a population of resident cardiac stem cells in the myocardium. Modern approaches to replenishment of massive cardiomyocyte loss via transplantation and transdifferentiation of adult and embryonic stem cells are discussed and the possibilities of using cell technologies for induction of tissue-specific regeneration of the myocardium are analyzed.

Reparative Osteogenesis during Transplantation of Mesenchymal Stem Cells

Reparative osteogenesis was studied after xenotransplantation of suspension cell graft from human mesenchymal stem cells. A model of experimental damage to rat femoral diaphysis was developed. The state of animals was satisfactory and non-depressed in the early and late postoperation period. We revealed no local pathological reactions and complications. Administration of mesenchymal stem cells into the area of bone defect accelerated and improved regeneration. Unilateral transplantation of the cell graft stimulated regeneration in the contralateral limb due to acceleration of bone tissue maturation. On day 90 after treatment the bone regenerate was completely developed in the area of defect in animals of various groups. The newly formed bone tissue was well integrated into the bone organ.

Transplantation of human embryonic myoblasts and bone marrow stromal cells into skeletal muscle of C57BL/10J-mdx mice

We studied expression of dystrophin in skeletal muscles of C57BL/10J-mdx mice after transplantation of human embryonic and fetal myoblasts and bone marrow stromal cells. Dystrophin-positive areas corresponding to the location of transplanted cell were detected in muscles of all recipient mice after transplantation of different cell cultures, but the distribution of dystrophin characteristic of normal muscle fibers was detected only after transplantation of embryonic myoblasts. Dystrophin distribution in muscle fibers after transplantation of fetal myoblasts and bone marrow stromal cells was atypical.

Isolation and phenotypical characterization of mesenchymal stem cells from human fetal thymus

Stem cells from human fetal thymus ectomesenchyma capable of forming colonies during in vitro culturing were isolated and characterized. Selection of culturing conditions showed that the growth and phenotypical characteristics of these cultures depended on seeding density and presence of basic fibroblast growth factor in the medium. After nonspecific inhibition of proliferation clonogenic cultures of thymic mesenchymal stem cells differentiated into myoblasts, formed characteristic myotubes, and expressed specific myogenesis markers. Colonies of thymic mesenchymal stem cells differentiated into chondrogenic, osteogenic, and adipogenic lines under conditions described for bone marrow mesenchymal stem cells. Cytofluorometric analysis of surface epitopes of thymic mesenchymal stem cells showed that the majority of cells expressed mesenchymal markers Thy-1, CD44, and CD105. Testing for CD34, CD38, CD45, and HLA-DR were negative in all cases. The main cell population (70-95%) did not express MHCl antigens during long-term culturing.