Abstract
Background/Objectives: Inflammatory processes, both acute and chronic, encompass a wide range of autoimmune, metabolic, and neurodegenerative conditions. Conventional treatments, primarily anti-inflammatories and immunosuppressants, provide partial relief but are often hampered by adverse effects and limited durability. Mesenchymal stem cells (MSCs) have emerged as a powerful new treatment due to their immunomodulatory and anti-inflammatory properties, primarily mediated through their secretome, which is a complex mixture of bioactive factors. Secretome-based therapeutic strategies show strong potential for controlling inflammation, mitigating oxidative stress, and supporting tissue regeneration and repair. However, the therapeutic efficacy of MSCs' secretome is subject to modification by concurrent anti-inflammatory drug regimens used in clinical settings. Methods: To evaluate the effect of combinatorial treatment strategies on the secretome of the MSCs, we employed an in vitro retinal inflammation model to investigate whether the exposure of the MSCs to five representative anti-inflammatory drugs (ketorolac, diclofenac, α-lipoic acid, N-acetyl-L-cysteine, and nicotinamide) impacts the functionality of the resulting secretome. Specifically, we evaluated the effect of the above-mentioned drugs on the anti-inflammatory properties of the secretome in relation to the secreted levels of two main MSC secretome factors-the Brain-Derived Neurotrophic Factor (BDNF) and the Vascular Endothelial Growth Factor (VEGF)-and on the secretome's pro-metabolic activity. Results: Our findings provide evidence that the presence of any of the tested drugs during MSC secretome production does not compromise its anti-inflammatory activity; BDNF and VEGF levels remain stable, and the secretome retains a high degree of its pro-metabolic effect. Conclusions: These results underscore the robustness and clinical resilience of MSC-based therapies, even when administered alongside pharmacological agents. This work advances the translational viability of MSC therapies for inflammatory diseases and supports the development of safe, combinatorial treatment strategies.