Figure 4.

Caco-2 cells grow on fructose, but not on butyrate or inulin. (a) Caco-2 cells were cultured in a real-time cell analyzer (RTCA, xCELLigence) to monitor cell growth on different carbon/energy sources, e.g., glucose (as positive control, dark blue line), fructose (pink line), butyrate (dark green), inulin (light green) or fructose-oligosaccharide (FOS, rose line) and compared to cell cultured in the absence of a carbon and energy source (bright red line). The inset in A shows the maximum growth rate (in Δcell index/h) of Caco-2 cells on glucose (blue bar), fructose (purple bar) and FOS (rose bar) when compared to the no added carbon source (red bar). Caco-2 cells grow at a similar pace on glucose and fructose. In contrast, butyrate causes only an initial small increase in cell index (green line between 24–48 h), after which the cell index goes down, suggesting cell death. In fact, butyrate blocks growth of Caco-2 on glucose (Orange line). Butyrate decreases Caco-2 cell proliferation in a dose-dependent manner both in (b) glucose-supplemented and (c) glucose-depleted media. All experiments were performed with two biological replicates, each with an N = 3 (glucose and inulin) and 2 (pectin). *P < .05