The effect of probiotic bacteria on transepithelial calcium transport and calcium uptake in human intestinal-like Caco-2 cells

While prebiotic substances have attracted considerable attention in terms of their stimulatory effect on intestinal calcium absorption, the potential influence of probiotic bacteria on calcium absorption has received little research emphasis. Therefore, the objective of this study was to investigate the effect of well-characterized probiotics (Lactobacillus salivarius (UCC 118) and Bifidobacterium infantis (UCC 35624)) on calcium uptake and transepithelial calcium transport in human intestinal-like, Caco-2, cells in culture. Cells were seeded onto permeable transport membranes and allowed to differentiate, over 16 d, into intestinal-like cell monolayers. Monolayers (n=12-20/ treatment) were then exposed to E. coli UCC 118, UCC 35624 (10(7) cfu/ml) or no bacteria (control) for 6 or 24 h prior to calcium transport studies. Calcium transport was unaffected by exposure of Caco-2 cells to E. coli, UCC 118 or UCC 35624 for 6 or 24 h. Calcium uptake into Caco-2 cell monolayers after 24 h was unaffected by UCC 35624, but was significantly (P<0.05) or tended (P=0.079) to be increased by UCC 118 and E. coli, respectively, relative to the control. In conclusion, the findings of this study which suggest that bacteria can enhance intestinal calcium uptake, if not calcium transport, highlights the need to undertake further studies in this, to date, vastly underinvestigated area.