On the basis of the TEER measurements, we observed that, as the number of passages of parental cells increased, a significant reduction in TEER associated with increased permeability occurred, accompanied by an increase in claudin 2 but not of occludin, and a decrease in MUC-2, all features attributable to a leaky gut, especially during aging and/or IBD onset. The gene discussed is CLDN2; the disease is inflammatory bowel disease.