Fig. 8

Indirect mesenchymal stromal cell contact modulates pro-inflammatory cross-talk between high glucose-exposed RPTEC/TERT1 cell monolayers and human macrophages. a Schematic diagram of the experimental protocol. b Graphs depicting the concentrations of IL-8, MCP-1, TNFα and IL-6 in the supernatants from monocyte-derived macrophages cultured with macrophage medium alone (medium), macrophage medium containing a stimulatory cocktail of LPS, IFNγ and TNFα (medium + M1 stimuli) and conditioned media from 48 h cultures of RPTEC/TERT1 cells alone (RPTEC) or RPTEC/TERT1 cells co-cultured with MSC-containing transwells (MSC + RPTEC) under high glucose (HG) and mannitol (MAN) conditions. Results for macrophages exposed to conditioned media from high glucose (HG) condition are represented in green and those from mannitol (MAN) are represented in blue bars. Results are expressed as mean ± SD of n = 3 technical replicates for each condition. Statistical analyses performed unpaired Student’s t test (* for MSC versus control; + for HG versus MAN). ****/++++p < 0.0001, ***/+++p < 0.001, **/++p < 0.01, */+p < 0.05, ns = not significant. c Schematic representation of the effect of high glucose on RPTEC, the subsequent inflammatory response of macrophages (left) and the modulatory effect of indirect contact between RPTEC and MSC on the downstream macrophage response (right)