Aim: In recent years, adipose-derived stromal cells (ASCs) have been investigated for use
as a cellular therapy, due to their immunomodulatory properties and their ability to regu-
late the function of immune cells, such as macrophages. Macrophages are plastic cells with
both pro- and anti-inflammatory functions. These features enable them to reduce inflam-
mation and prevent fibrosis. Fibrosis can arise as a result of prolonged inflammation and
this leads to decreased tissue functionality. The ASCs can interact with the surroundings
cell through both paracrine secretion and cell-cell contact. However, the exact mechanisms
of action for the interactions between ASCs and macrophages are still unknown. There-
fore, the aim of this study was to investigate the effect of ASCs on the fibrotic effects of
macrophages.
Methods: To develop a macrophage-ASC-coculture, the optimal concentration of activat-
ing stimuli, lipopolysaccharide and interferon-γ, was determined by measuring the concen-
tration of secreted tumor necrosis factor-α by the macrophages. Hereafter, macrophages
were isolated from the ASCs using Dynabeads coated with CD90 antibody, and then seeded
onto an extracellular matrix derived from transforming growth factor-β-stimulated fibrob-
lasts. After six days, the levels of collagen I and III were determined as a measure of
deposition of extracellular matrix. Optimisation of fibroblast seeding density allowed them
to create a dense extracellular matrix, which was determined through staining with Sirius
Red (0.1%) in Picric Acid.
Results and Conclusion: A macrophage-ASC-coculture model was established, and the
optimal concentrations of lipopolysaccharide and interferon-γ were found to be 100 ng/mL
and 20 ng/mL, respectively. After six days of coculture with fibroblasts, the ASC-treated
macrophages had resulted in significantly decreased levels of collagen I and III, which
suggests that macrophages are able to affect the deposition of extracellular matrix. The
optimal seeding density of the macrophages was 6250 M1/cm2 at which concentration the
greatest significant and numerical difference between the ASC-treated macrophages and
the mature macrophages was found.