title: The effect of mucin on bacterial translocation in I-407 fetal and Caco-2 adult enterocyte cultured cell lines.
abstract: Although the intestinal mucosa forms a crucial barrier between the host and the environment, bacterial translocation (BT) occurs frequently in neonates and may be a source of sepsis. The intestinal mucous gel layer is thought to be a vital component of the gut barrier and is composed, in part, of a family of glycoproteins known as mucins. Our aim was to study the effects of mucin on BT in an enterocyte cell-culture model using a fetal (I-407) and an adult (Caco-2) intestinal cell line. I-407 and Caco-2 cells were grown to confluence on porous filters in a two-chamber Transwell system. The integrity of the monolayers was confirmed by transepithelial electrical resistance (TEER) and permeability using the macromolecule dextran blue. Cells were treated with mucin (40 mg/ml) prior to inoculation of 1 x 10(6) Escherichia coli C25. The magnitude of BT was determined quantitatively by culturing the samples from the basal chamber of the wells and was expressed as log 10 [Colony Forming Units (CFU)/ml]. Statistical analysis was performed by the Mann-Whitney U test with statistical significance at P < 0.05. Mucin inhibited BT across both fetal and adult cultured enterocyte monolayers; however, the inhibitory effect was less on the fetal cells compared to the adult cells. Dextran-blue studies showed that monolayers were intact throughout the experiments. Despite 98% inhibition of BT, mucin had a statistically significant effect on post-bacterial inoculation TEER in Caco-2 cells and no effect in I-407 cells. The ability of mucin, a mucous-barrier glycoprotein, to inhibit BT across immature intestinal enterocytes, as in the neonate, may be diminished compared to mature adult enterocytes.
authors.affiliation: Section of Pediatric Surgery, F3970 Mott Children's Hospital, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109-0245, USA.
authors.forename: A S
authors.initials: AS
authors.lastname: Gork
authors.forename: N
authors.initials: N
authors.lastname: Usui
authors.forename: E
authors.initials: E
authors.lastname: Ceriati
authors.forename: R A
authors.initials: RA
authors.lastname: Drongowski
authors.forename: M D
authors.initials: MD
authors.lastname: Epstein
authors.forename: A G
authors.initials: AG
authors.lastname: Coran
authors.forename: C M
authors.initials: CM
authors.lastname: Harmon
mesh_terms: D000328:Adult; D018988:Bacterial Translocation / Q000187:drug effects*; D018938:Caco-2 Cells; D004926:Escherichia coli / Q000254:growth & development; D005333:Fetus; D006801:Humans; D007231:Infant, Newborn; D007413:Intestinal Mucosa / Q000166:cytology / Q000382:microbiology; D009077:Mucins / Q000494:pharmacology*
chemical_list: D009077:Mucins