Osteogenic Potential of Mesenchymal Stem Cells from Adipose Tissue, Bone Marrow and Hair Follicle Outer Root Sheath in a 3D Crosslinked Gelatin-Based Hydrogel

Photobiomodulation Dose-Response on Adipose-Derived Stem Cell Osteogenesis in 3D Cultures

Osteoporosis and other degenerative bone diseases pose significant challenges to global healthcare systems due to their prevalence and impact on quality of life. Current treatments often alleviate symptoms without fully restoring damaged bone tissue, highlighting the need for innovative approaches like stem cell therapy. Adipose-derived mesenchymal stem cells (ADMSCs) are particularly promising due to their accessibility, abundant supply, and strong differentiation potential. However, ADMSCs tend to favor adipogenic pathways, necessitating the use of differentiation inducers (DIs), three-dimensional (3D) hydrogel environments, and photobiomodulation (PBM) to achieve targeted osteogenic differentiation. This study investigated the combined effects of osteogenic DIs, a fast-dextran hydrogel matrix, and PBM at specific wavelengths and fluences on the proliferation and differentiation of immortalized ADMSCs into osteoblasts. Near-infrared (NIR) and green (G) light, as well as their combination, were used with fluences of 3 J/cm2, 5 J/cm2, and 7 J/cm2. The results showed statistically significant increases in alkaline phosphatase levels, a marker of osteogenic differentiation, with G light at 7 J/cm2 demonstrating the most substantial impact on ADMSC differentiation. Calcium deposits, visualized by Alizarin red S staining, appeared as early as 24 h post-treatment in PBM groups, suggesting accelerated osteogenic differentiation. ATP luminescence assays indicated increased proliferation in all experimental groups, particularly with NIR and NIR-G light at 3 J/cm2 and 5 J/cm2. MTT viability and LDH membrane permeability assays confirmed enhanced cell viability and stable cell health, respectively. In conclusion, PBM significantly influences the differentiation and proliferation of hydrogel-embedded immortalized ADMSCs into osteoblast-like cells, with G light at 7 J/cm2 being particularly effective. These findings support the combined use of 3D hydrogel matrices and PBM as a promising approach in regenerative medicine, potentially leading to innovative treatments for degenerative bone diseases.

The Effect of Clopidogrel and Ticagrelor on Human Adipose Mesenchymal Stem Cell Osteogenic Differentiation Potential: In Vitro Comparative Study

Ticagrelor (TICA) and clopidogrel (CLP) are extensively used antiplatelet drugs that act by antagonizing the P2Y12 receptors that are found on platelets in addition to bone cells. Aim. The purpose of this study was to investigate the effect of clopidogrel and ticagrelor on stem cells osteogenic differentiation in vitro. Methods. Human adipose-derived mesenchymal stem cells (hAd-MSCs) were divided into (1) control group, (2) osteogenic group (osteo group), (3) clopidogrel group (CLP group), and (4) ticagrelor group (TICA group). The osteogenic differentiation potential was determined by mineralization nodule formation using Alizarin Red S staining, measuring ALP enzyme activity by alkaline phosphatase assay. Quantitative determination for osteogenic markers included osteocalcin (OC); runt-related transcription factor 2 (RUNX2) performed using western blot; osteoprotegerin (OPG) using enzyme-linked immunosorbent assay (ELISA) and inflammatory markers; and tumor necrosis factor (TNF-α) and interleukin-6 (IL-6) measured using real-time polymerase chain reaction quantitative (RT-PCR) and ELISA. Results. In comparison to all study groups, the TICA group showed significant increase in the mineralized extracellular matrix, ALP enzyme activity, and bone markers expression as RUNX2 (P < 0.0001), OC, and OPG (P < 0.05). The expression of IL-6 and TNF-α was determined by RT-qPCR and ELISA techniques. TICA and CLP significantly decreased both markers compared to the control group. The TICA group showed statistically significant lower levels of both markers (P < 0.0001) than the CLP and control groups via the ELISA technique. Conclusion. TICA may possess a positive effect on hAd-MSCs osteogenic differentiation compared to CLP.

Radiofluorination of an Anionic, Azide-Functionalized Teroligomer by Copper-Catalyzed Azide-Alkyne Cycloaddition

This study describes the synthesis, radiofluorination and purification of an anionic amphiphilic teroligomer developed as a stabilizer for siRNA-loaded calcium phosphate nanoparticles (CaP-NPs). As the stabilizing amphiphile accumulates on nanoparticle surfaces, the fluorine-18-labeled polymer should enable to track the distribution of the CaP-NPs in brain tumors by positron emission tomography after application by convection-enhanced delivery. At first, an unmodified teroligomer was synthesized with a number average molecular weight of 4550 ± 20 Da by free radical polymerization of a defined composition of methoxy-PEG-monomethacrylate, tetradecyl acrylate and maleic anhydride. Subsequent derivatization of anhydrides with azido-TEG-amine provided an azido-functionalized polymer precursor (o14PEGMA-N₃) for radiofluorination. The ¹⁸F-labeling was accomplished through the copper-catalyzed cycloaddition of o14PEGMA-N₃ with diethylene glycol-alkyne-substituted heteroaromatic prosthetic group [¹⁸F]2, which was synthesized with a radiochemical yield (RCY) of about 38% within 60 min using a radiosynthesis module. The ¹⁸F-labeled polymer [¹⁸F]fluoro-o14PEGMA was obtained after a short reaction time of 2-3 min by using CuSO₄/sodium ascorbate at 90 °C. Purification was performed by solid-phase extraction on an anion-exchange cartridge followed by size-exclusion chromatography to obtain [¹⁸F]fluoro-o14PEGMA with a high radiochemical purity and an RCY of about 15%.