Long-term exposure to LPS induces a loss of β-cell viability. Under the same conditions described in the legend to Figure 2, cell viability was analyzed by flow cytometry using TMRE staining. (a) Histogram showing the percentage of TMRE-positive cells upon treatment with 50 ng/mL LPS (red line), untreated control cells (green line) and isotype-matched control for TLR4 staining (dotted black line). (b) Values represent the relative percentage of TMRE-positive β-cells. Data are expressed as mean ± SD for β-cell cultures derived from different pancreas donors (n = 7), incubated with or without LPS 50 ng/mL for 48 h and analyzed in triplicate. Statistically significant differences are indicated as (**) p < 0.005, compared to non-treated control cells.