Evaluation of Human Stem Cell Conditioned Medium and Culture Conditions on Alleviating Elastase-Compromised Human Aortic Smooth Muscle Cell Function.

Abstract

Cardiovascular health depends critically on the integrity of the vascular extracellular matrix (ECM) and the behavior of vascular smooth muscle cells (VSMCs), both of which can be adversely affected in vascular diseases. This study quantitatively evaluates the therapeutic potential of conditioned medium (CM) derived from bone marrow (BM-MSCs) and adipose-derived stem cells (ADSCs) in an elastase-injured human aortic smooth muscle cell (HASMC) model. We systematically varied seeding densities (2000, 5000, and 10,000 cells/cm²) and serum conditions to optimize the SC-SMC secretome for vascular repair. Our results indicate that neither BM-SMC nor AD-SMC CM significantly enhanced lysyl oxidase (LOX) activity. In fact, serum-supplemented BM-SMC CM significantly suppressed LOX activity at seeding densities of 2000 cells/cm² (p = 0.0378) and 10,000 cells/cm² (p = 0.0080) compared to injured untreated controls. High-density AD-SMC CM (10,000 cells/cm²) also resulted in a significant decrease in elastin levels (p < 0.05). In addition, serum presence was critical for maintaining the reparative phenotype. Serum-free (SF) conditions for both cell sources led to widespread, statistically significant reductions (p < 0.0001) in key repair and inflammatory biomarkers, including PDGF-AA, Leptin, Lipocalin-2, Osteopontin, RBP4, MMP-1, and IL-6. IL-11 emerged as a primary discriminatory biomarker, showing significant differences between BM and AD treatments at high seeding densities, with both sources causing a significant decrease (p < 0.0001) compared to injured untreated controls. These findings demonstrate that seeding density and serum conditions are critical variables that quantitatively modulate the efficacy of SC-SMC-CM. The study highlights that BM-SMC-derived CM offers a more stable platform for elastin maintenance under serum-free conditions, providing a foundation for developing tailored, cell-free regenerative therapies for cardiovascular disease.