Article 1 A Fixed Combination of Probiotics and Herbal 2 Extracts Attenuates Intestinal Barrier Dysfunction 3 from Inflammatory Stress 4 Veronica Cocetta 1 , Daniela Catanzaro 1 , Vittoria Borgonetti 1,2 , Eugenio Ragazzi 1 , Maria Cecilia 5 Giron 1 , Paolo Governa 2,3 , Ilaria Carnevali 4 , Marco Biagi 2,3 * and Monica Montopoli 1,3 * 6 1 Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 35131 Padova, Italy. 7 monica.montopoli@unipd.it 8 2 Department of Physical Sciences, Earth and Environment, University of Siena, 53100 Siena, Italy. 9 biagi4@unisi.it 10 3 SIFITLab, Italian Society of Phytotherapy, 53100 Siena, Italy. paolo.governa@sifitlab.it 11 4 Schwabe Pharma Italia, 39044 Egna, Bolzano. ilaria.carnevali@schwabe.it 12 13 * Correspondence: biagi4@unisi.it, Tel.: +390577233514; monica.montopoli@unipd.it 14 Abstract: Maintenance of intestinal barrier integrity is crucial for preventing inflammatory bowel 15 diseases (IBDs) onset and exacerbations. In this work we study the effect of a fixed combination of 16 Lactobacillus reuteri and Lactobacillus acidophilus and herbal extracts in an in vitro inflammation 17 experimental model. Caco-2 cell monolayer was exposed to INF-γ+TNF-α or to LPS; Trans Epithelial 18 Electrical Resistance (TEER) and paracellular permeability were investigated. ZO-1 and occludin 19 tight junctions (TJs) were also investigated by mean of immunofluorescence. The pre-treatment with 20 the fixed combination of probiotics and herbal extracts prevented the inflammation-induced TEER 21 decrease, paracellular permeability increase and TJs translocation. In summary the fixed 22 combination of probiotics and herbal extracts investigated in this research was found to be an 23 interesting candidate for targeting the re-establishment of intestinal barrier function in IBDs 24 conditions. 25 Keywords: IBD; intestinal barrier; Lactobacillus reuteri; Lactobacillus acidophilus; Trans Epithelial 26 Electrical Resistance (TEER) 27 28 1. Introduction 29 Intestinal barrier dysfunctions are strictly linked to inflammatory bowel diseases (IBD) such as 30 Chron’s disease and ulcerative colitis 1. In fact, an increase of intestinal epithelial cells permeability 31 leads to a strong antigenic response, primarily affected by microbial hosts and post digestive toxins 32 2. The management of intestinal inflammation is pivotal to avoid exacerbations and autoimmune 33 diseases onset and, thus, non-steroidal anti-inflammatory drugs such as aminosalicylates, or 34 glucocorticoids are commonly used 3. In case of active IBDs and severe symptoms, 35 immunosuppressive drugs are also used [4]; nevertheless, intestinal barrier homeostasis and 36 maintenance is scarcely considered in conventional pharmacotherapy and currently the interest in 37 integrative and complementary therapies is increasing 5. Elevated levels of reactive oxygen and 38 nitrogen species (ROS and RNS) and increased release of pro-inflammatory cytokines are, 39 respectively, very relevant in initiation and progression of intestinal barrier dysregulation 1. These 40 considerations have been suggesting that antioxidant and anti-inflammatory agents could be 41 conveniently used and recently our group demonstrated how Boswellia serrata Roxb. gum resin and 42 its chemical marker acetyl-11-keto--boswellic acid (AKBA) resulted to be effective in preserving 43 Caco-2 intestinal epithelial cells barrier capacity ameliorating oxidative inflammatory and 44 permeability parameters after H202 and INF-γ and TNF α stimuli [1]. Other natural products and 45 dietary supplements were investigated in intestinal barrier regulation. Beside to natural compounds 46 Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 29 December 2017 doi:10.20944/preprints201712.0199.v1 © 2017 by the author(s). Distributed under a Creative Commons CC BY license.