Ricerc@Sapienza

AIM To investigate the adhesion and anti-inflammatory effects of Lactobacillus rhamnosus GG (LGG) in the colonic mucosa of healthy and ulcerative colitis (UC) patients, both in vivo and ex vivo in an organ culture model. METHODS For the ex vivo experiment, a total of 98 patients (68 UC patients and 30 normal subjects) were included. Endoscopic biopsies were collected and incubated with and without LGG or LGG-conditioned media to evaluate the mucosal adhesion and anti-inflammatory effects [reduction of tumor necrosis factor alpha (TNFa) and interleukin (IL)-17 expression] of the bacteria, and extraction of DNA and RNA for quantification by real-time (RT)-PCR occurred after the incubation. A dose-response study was performed by incubating biopsies at "regular", double and 5 times higher doses of LGG. For the in vivo experiment, a total of 42 patients (20 UC patients and 22 normal controls) were included. Biopsies were taken from the colons of normal subjects who consumed a commercial formulation of LGG for 7 d prior to the colonoscopy, and the adhesion of the bacteria to the colonic mucosa was evaluated by RT-PCR and compared with that of control biopsies from patients who did not consume the formulation. LGG adhesion and TNFa and IL-17 expression were compared between UC patients who consumed a regular or double dose of LGG supplementation prior to colonoscopy. RESULTS In the ex vivo experiment, LGG showed consistent adhesion to the distal and proximal colon in normal subjects and UC patients, with a trend towards higher concentrations in the distal colon, and in UC patients, adhesion was similar in biopsies with active and quiescent inflammation. In addition, bioptic samples from UC patients incubated with LGG conditioned media (CM) showed reduced expression of TNFa and IL-17 compared with the corresponding expression in controls (P