This study investigates the impact of acetylsalicylic acid (ASA), also known as aspirin, on adipose tissue-derived stem cells (ASCs), aiming to elucidate its dose-dependent effects on morphology, viability, proliferation, and osteogenic differentiation. Isolated and characterized human ASCs were exposed to 0 µM, 100 µM, 200 µM, 400 µM, 800 µM, 1000 µM, 10,000 µM, and 16,000 µM of ASA in vitro. Cell morphology, viability, and proliferation were evaluated with fluorescent live/dead staining, alamarBlue viability reagent, and CyQUANT^® cell proliferation assay, respectively. Osteogenic differentiation under stimulation with 400 µM or 1000 µM of ASA was assessed with alizarin red staining and qPCR of selected osteogenic differentiation markers (RUNX2, SPP1, ALPL, BGLAP) over a 3- and 21-day-period. ASA doses ≤ 1000 µM showed no significant impact on cell viability and proliferation. Live/dead staining revealed a visible reduction in viable cell confluency for ASA concentrations ≥ 1000 µM. Doses of 10,000 µM and 16,000 µM of ASA exhibited a strong cytotoxic and anti-proliferative effect in ASCs. Alizarin red staining revealed enhanced calcium accretion under the influence of ASA, which was macro- and microscopically visible and significant for 1000 µM of ASA (p = 0.0092) in quantification if compared to osteogenic differentiation without ASA addition over a 21-day-period. This enhancement correlated with a more pronounced upregulation of osteogenic markers under ASA exposure (ns). Our results indicate a stimulatory effect of 1000 µM of ASA on the osteogenic differentiation of ASCs. Further research is needed to elucidate the precise molecular mechanisms underlying this effect; however, this discovery suggests promising opportunities for enhancing bone tissue engineering with ASCs as cell source.

Aspirin (ASA) is one of the most used medications worldwide and has shown various effects on cellular processes, including stem cell differentiation. However, the effect of ASA on adipogenesis of adipose tissue-derived stem cells (ASCs) remains largely unknown. Considering the potential application of ASCs in regenerative medicine and cell-based therapies, this study investigates the effects of ASA on adipogenic differentiation in human ASCs. ASCs were exposed to varying concentrations of ASA (0 µM, 400 µM, and 1000 µM) and evaluated for changes in morphology, migration, and adipogenic differentiation. While ASA exposure did not affect self-renewal potential, migration ability, or cell morphology, it significantly reduced lipid vacuole formation at 1000 µM after 21 days of adipogenic differentiation (p = 0.0025). This visible inhibition correlated with decreased expression of adipogenic markers (PPARG, ADIPOQ, and FABP4) and the proliferation marker MKi67 under ASA exposure in comparison to the control (ns). Overall, the findings demonstrate that ASA inhibits adipogenic differentiation of human ASCs in a dose-dependent manner in vitro, contrasting its known role in promoting osteogenic differentiation. This research highlights ASA’s complex effects on ASCs and emphasizes the need for further investigation into its mechanisms and potential therapeutic applications in obesity and metabolic diseases. The inhibitory effects of ASA on adipogenesis should be considered in cell-based therapies using ASCs.