Enhanced angiogenic activity of dimethyloxalylglycine-treated canine adipose tissue-derived mesenchymal stem cells

Effect of Dimethyloxalylglycine on Stem Cells Osteogenic Differentiation and Bone Tissue Regeneration-A Systematic Review

Dimethyloxalylglycine (DMOG) has been found to stimulate osteogenesis and angiogenesis of stem cells, promoting neo-angiogenesis in bone tissue regeneration. In this review, we conducted a comprehensive search of the literature to investigate the effects of DMOG on osteogenesis and bone regeneration. We screened the studies based on specific inclusion criteria and extracted relevant information from both in vitro and in vivo experiments. The risk of bias in animal studies was evaluated using the SYRCLE tool. Out of the 174 studies retrieved, 34 studies met the inclusion criteria (34 studies were analyzed in vitro and 20 studies were analyzed in vivo). The findings of the included studies revealed that DMOG stimulated stem cells' differentiation toward osteogenic, angiogenic, and chondrogenic lineages, leading to vascularized bone and cartilage regeneration. Addtionally, DMOG demonstrated therapeutic effects on bone loss caused by bone-related diseases. However, the culture environment in vitro is notably distinct from that in vivo, and the animal models used in vivo experiments differ significantly from humans. In summary, DMOG has the ability to enhance the osteogenic and angiogenic differentiation potential of stem cells, thereby improving bone regeneration in cases of bone defects. This highlights DMOG as a potential focus for research in the field of bone tissue regeneration engineering.

Macrophage induces anti-cancer drug resistance in canine mammary gland tumor spheroid

Tumor-associated macrophages (TAMs) play an important role in the tumor microenvironment by producing cytokines and growth factors. Furthermore, TAMs play multifunctional roles in tumor progression, immune regulation, metastasis, angiogenesis, and chemoresistance. Hypoxia in the tumor microenvironment induces tumor-supporting transformation of TAMs, which enhances tumor malignancy through developing anti-cancer resistance, for example. In this study, a hybrid spheroid model of canine mammary gland tumor (MGT) cell lines (CIPp and CIPm) and canine macrophages (DH82) was established. The effects of hypoxia induced by the spheroid culture system on the anti-cancer drug resistance of canine MGT cells were investigated. A hybrid spheroid was created using an ultralow-adhesion plate. The interactions between canine MGT cells and DH82 were investigated using a co-culture method. When co-cultured with DH82, cell viability and expression levels of tumor growth factors and multi-drug resistance genes were increased in canine MGT cells under doxorubicin. Additionally, doxorubicin-induced apoptosis and G2/M cell cycle arrest were attenuated in canine MGT cells co-cultured with DH82. In conclusion, the hybrid spheroid model established in this study reflects the hypoxic TME, allowing DH82 to induce anti-cancer drug resistance in canine MGT cells.

Mesenchymal Stem Cells for Treating Alzheimer's Disease: Cell Therapy and Chemical Reagent Pretreatment

As the size of the population aged 65 and older continues to grow, the incidence and mortality rates of Alzheimer's disease (AD) are increasing annually. Unfortunately, current treatments only treat symptoms temporarily and do not alter the patients' life expectancy or course of AD. Mesenchymal stem cells (MSCs) have shown a certain therapeutic potential in neurodegenerative diseases including AD due to their neuroinflammatory regulation and neuroprotective effects. However, the low survival and homing rates of MSCs after transplantation seriously affect their therapeutic effectiveness. Therefore, appropriate in vitro preconditioning is necessary to increase the survival and homing rates of MSCs to improve their effectiveness in treating AD. Here we summarize the therapeutic mechanisms of MSCs in AD and the chemical reagents used for the pretreatment of MSCs.

Pre-conditioning Strategies for Mesenchymal Stromal/Stem Cells in Inflammatory Conditions of Livestock Species

Mesenchymal stem/stromal cells (MSCs) therapy has been a cornerstone of regenerative medicine in humans and animals since their identification in 1968. MSCs can interact and modulate the activity of practically all cellular components of the immune response, either through cell-cell contact or paracrine secretion of soluble mediators, which makes them an attractive alternative to conventional therapies for the treatment of chronic inflammatory and immune-mediated diseases. Many of the mechanisms described as necessary for MSCs to modulate the immune/inflammatory response appear to be dependent on the animal species and source. Although there is evidence demonstrating an in vitro immunomodulatory effect of MSCs, there are disparate results between the beneficial effect of MSCs in preclinical models and their actual use in clinical diseases. This discordance might be due to cells' limited survival or impaired function in the inflammatory environment after transplantation. This limited efficacy may be due to several factors, including the small amount of MSCs inoculated, MSC administration late in the course of the disease, low MSC survival rates in vivo, cryopreservation and thawing effects, and impaired MSC potency/biological activity. Multiple physical and chemical pre-conditioning strategies can enhance the survival rate and potency of MSCs; this paper focuses on hypoxic conditions, with inflammatory cytokines, or with different pattern recognition receptor ligands. These different pre-conditioning strategies can modify MSCs metabolism, gene expression, proliferation, and survivability after transplantation.

Gene expression of adipokines and inflammatory cytokines in peripheral blood mononuclear cells of obese dogs

Background

Peripheral blood mononuclear cells (PBMCs) have been identified as a possible marker of inflammation in obesity. Understanding the expression of pro‐ and anti‐inflammatory cytokines in PBMCs in obese dogs will help control obesity‐related inflammatory diseases.

Objectives

The aim of this study was to evaluate the role of PBMCs in obesity‐associated chronic inflammation by analyzing the expression of adipokines and inflammatory cytokines.

Methods

Blood samples were obtained from 25 subjects and real‐time quantitative polymerase chain reaction determinations were performed to quantify the gene expression levels of adipokines and inflammatory cytokines, including TNF‐α, IL‐17, leptin, MCP‐1, and adiponectin, in the PBMCs.

Results

The results showed that the gene expression levels of TNF‐α (p < 0.001), IL‐17 (p < 0.0001), and leptin (p < 0.0001) were strongly upregulated in the PBMCs of obese dogs compared to that in non‐obese dogs.

Conclusions

The changes in gene expression levels of inflammation‐related adipokines and pro‐inflammatory cytokines occur in PBMCs, which may contribute to the low‐grade chronic inflammation that is present in obesity.

Translational Animal Models Provide Insight Into Mesenchymal Stromal Cell (MSC) Secretome Therapy

The therapeutic potential of the mesenchymal stromal cell (MSC) secretome, consisting of all molecules secreted by MSCs, is intensively studied. MSCs can be readily isolated, expanded, and manipulated in culture, and few people argue with the ethics of their collection. Despite promising pre-clinical studies, most MSC secretome-based therapies have not been implemented in human medicine, in part because the complexity of bioactive factors secreted by MSCs is not completely understood. In addition, the MSC secretome is variable, influenced by individual donor, tissue source of origin, culture conditions, and passage. An increased understanding of the factors that make up the secretome and the ability to manipulate MSCs to consistently secrete factors of biologic importance will improve MSC therapy. To aid in this goal, we can draw from the wealth of information available on secreted factors from MSC isolated from veterinary species. These translational animal models will inspire efforts to move human MSC secretome therapy from bench to bedside.

3D-culture models as drug-testing platforms in canine lymphoma and their cross talk with lymph node-derived stromal cells

BACKGROUND

Malignant lymphoma is the most common hematopoietic malignancy in dogs, and relapse is frequently seen despite aggressive initial treatment. In order for the treatment of these recurrent lymphomas in dogs to be effective, it is important to choose a personalized and sensitive anticancer agent. To provide a reliable tool for drug development and for personalized cancer therapy, it is critical to maintain key characteristics of the original tumor.

OBJECTIVES

In this study, we established a model of hybrid tumor/stromal spheroids and investigated the association between canine lymphoma cell line (GL-1) and canine lymph node (LN)-derived stromal cells (SCs).

METHODS

A hybrid spheroid model consisting of GL-1 cells and LN-derived SC was created using ultra low attachment plate. The relationship between SCs and tumor cells (TCs) was investigated using a coculture system.

RESULTS

TCs cocultured with SCs were found to have significantly upregulated multidrug resistance genes, such as P-qp, MRP1, and BCRP, compared with TC monocultures. Additionally, it was revealed that coculture with SCs reduced doxorubicin-induced apoptosis and G2/M cell cycle arrest of GL-1 cells.

CONCLUSIONS

SCs upregulated multidrug resistance genes in TCs and influenced apoptosis and the cell cycle of TCs in the presence of anticancer drugs. This study revealed that understanding the interaction between the tumor microenvironment and TCs is essential in designing experimental approaches to personalized medicine and to predict the effect of drugs.

Dimethyloxallyl glycine/nanosilicates-loaded osteogenic/angiogenic difunctional fibrous structure for functional periodontal tissue regeneration

The coupled process of osteogenesis-angiogenesis plays a crucial role in periodontal tissue regeneration. Although various cytokines or chemokines have been widely applied in periodontal in situ tissue engineering, most of them are macromolecular proteins with the drawbacks of short effective half-life, poor stability and high cost, which constrain their clinical translation. Our study aimed to develop a difunctional structure for periodontal tissue regeneration by incorporating an angiogenic small molecule, dimethyloxalylglycine (DMOG), and an osteoinductive inorganic nanomaterial, nanosilicate (nSi) into poly (lactic-co-glycolic acid) (PLGA) fibers by electrospinning. The physiochemical properties of DMOG/nSi-PLGA fibrous membranes were characterized. Thereafter, the effect of DMOG/nSi-PLGA membranes on periodontal tissue regeneration was evaluated by detecting osteogenic and angiogenic differentiation potential of periodontal ligament stem cells (PDLSCs) in vitro. Additionally, the fibrous membranes were transplanted into rat periodontal defects, and tissue regeneration was assessed with histological evaluation, micro-computed tomography (micro-CT), and immunohistochemical analysis. DMOG/nSi-PLGA membranes possessed preferable mechanical property and biocompatibility. PDLSCs seeded on the DMOG/nSi-PLGA membranes showed up-regulated expression of osteogenic and angiogenic markers, higher alkaline phosphatase (ALP) activity, and more tube formation in comparison with single application. Further, in vivo study showed that the DMOG/nSi-PLGA membranes promoted recruitment of CD90+/CD34− stromal cells, induced angiogenesis and osteogenesis, and regenerated cementum-ligament-bone complex in periodontal defects. Consequently, the combination of DMOG and nSi exerted admirable effects on periodontal tissue regeneration. DMOG/nSi-PLGA fibrous membranes could enhance and orchestrate osteogenesis-angiogenesis, and may have the potential to be translated as an effective scaffold in periodontal tissue engineering.

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Dual-load fibrous structure possessed preferable mechanical property and biocompatibility.

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Fibrous structure can orchestrate and enhance osteogenesis-angiogenesis coupling.

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Difunctional fibrous structure can recruit CD90+/CD34− stromal cells to periodontal defects.

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Difunctional fibrous structure obtained functional periodontal tissue regeneration.