Canine Mesenchymal Stromal Cell-Mediated Bone Regeneration is Enhanced in the Presence of Sub-Therapeutic Concentrations of BMP-2 in a Murine Calvarial Defect Model

Impact of Dexamethasone on Three-Dimensional Stem Cell Spheroids: Morphology, Viability, Osteogenic Differentiation

Background and Objectives: Dexamethasone has been widely researched for its ability to promote osteogenic differentiation in mesenchymal stem cells in basic research. This study focused on examining the effects of dexamethasone on both cell viability and osteogenic differentiation in three-dimensional stem cell spheroids. Materials and Methods: These spheroids were created using concave microwells and exposed to dexamethasone at concentrations ranging from 0 μM to 100 μM, including intermediate levels of 0.1 μM, 1 μM, and 10 μM. Microscopic analysis was used to qualitatively assess cellular viability, while a water-soluble tetrazolium salt-based assay provided quantitative viability data. Osteogenic differentiation was evaluated by measuring alkaline phosphatase activity and calcium deposition using Alizarin Red staining. Additionally, the expression levels of genes associated with osteogenesis were measured through quantitative polymerase chain reaction. Results: The spheroids successfully self-assembled within the first 24 h and maintained their structural integrity over a seven-day period. Analysis of cell viability showed no statistically significant differences across the various dexamethasone concentrations tested. Although there was an observed increase in alkaline phosphatase activity and calcium deposition following dexamethasone treatment, these differences were not statistically significant. RUNX2 gene expression was upregulated in the 1 μM, 10 μM, and 100 μM groups, while COL1A1 expression significantly increased at 0.1 μM and 1 μM. Conclusions: These results indicate that dexamethasone supports cell viability and enhances RUNX2 and COL1A1 expression in stem cell spheroids.

Mesenchymal stromal cell isolation from pond slider (Trachemys scripta) adipose tissue obtained during routine neutering: a model for turtle species

Introduction

Mesenchymal stromal cells (MSCs) hold great clinical potential in veterinary regenerative medicine. However, a notable gap exists in the literature regarding the isolation and characterization of these cells in reptiles. The objective of this study was to evaluate the feasibility of isolating adipose tissue-derived mesenchymal stem cells (MSCs) from pond slider (Trachemys scripta) tissue samples collected during routine neutering procedures.

Methods

Adipose tissue samples were obtained from five animals and processed using an enzymatic procedure. The resulting cell suspension was subsequently cultured at 28°C in a controlled atmosphere with 5% CO2. The cell growth rates were evaluated through direct counting of cells up to passage 7. The colony-forming unit (CFU) capacity of MSCs was evaluated in low-density cell cultures, and the ability of the cells to differentiate into adipogenic, chondrogenic and osteogenic lineages was assessed. The cell phenotype was characterized at the molecular level using reverse transcription-polymerase chain reaction (RT-PCR) and amplicon sequencing, with a focus on markers commonly used for gene expression profiling of mammalian MSCs.

Results

The cells demonstrated the capacity to differentiate into adipogenic, chondrogenic, and osteogenic lineages. RT-PCR revealed the expression of CD105, CD73, CD44, and CD90, whereas CD34 and HLA-DRA were not expressed. Sequence homology analysis demonstrated that the amplicons matched the sequences reported in the Trachemys scripta whole-genome shotgun sequence. This study represents the first investigation aimed at the isolation, in vitro expansion, and characterization of reptile adipose tissue-derived MSCs.

Discussion

The results demonstrate the feasibility of isolating MSC-like cells from chelonian adipose tissue and underscore their potential for application in regenerative medicine for both companion reptiles and endangered wild species.

Effects of Insulin-like Growth Factor 1 on the Maintenance of Cell Viability and Osteogenic Differentiation of Gingiva-Derived Mesenchymal Stem Cell Spheroids

Background and Objectives: Insulin-like growth factor-1 (IGF-1) plays a vital role in various cellular processes, including those involving stem cells. This study evaluated the effects of IGF-1 on cell survival, osteogenic differentiation, and mRNA expression in gingiva-derived mesenchymal stem cell spheroids. Materials and Methods: Using concave microwells, spheroids were generated in the presence of IGF-1 at concentrations of 0, 10, and 100 ng/mL. Cellular vitality was qualitatively assessed using microscopy, while a water-soluble tetrazolium salt-based assay kit quantified cellular viability. Osteogenic differentiation was evaluated via alkaline phosphatase activity and an anthraquinone dye test to measure calcium deposition. Additionally, quantitative polymerase chain reaction (qPCR) analysis was performed to determine the expression of RUNX2 and COL1A1. Results: By day 1, the stem cell spheroids had successfully formed, and their morphology remained stable over the following 7 days. The IGF-1 concentrations tested showed no significant differences in cell viability. Similarly, alkaline phosphatase activity on day 7 revealed no observable changes. However, on day 7, the incorporation of IGF-1 led to an increase in Alizarin Red staining, indicative of enhanced calcium deposition. Notably, an IGF-1 concentration of 100 ng/mL significantly upregulated the expression of COL1A1. Conclusions: These findings suggest that IGF-1 supports the maintenance of cell viability and promotes the expression of COL1A1 in gingiva-derived mesenchymal stem cell spheroids, highlighting its potential role in enhancing osteogenic differentiation. Future research should include long-term studies to evaluate the sustainability of IGF-1-induced effects on stem cell spheroids.