The Intestinal Barrier in Irritable Bowel Syndrome: Subtype-Specific Effects of the Systemic Compartment in an In Vitro Model

Abstract

BackgroundIrritable bowel syndrome (IBS) is a disorder with multifactorial pathophysiology. Intestinal barrier may be altered, especially in diarrhea-predominant IBS (IBS-D). Several mediators may contribute to increased intestinal permeability in IBS.AimWe aimed to assess effects of tryptase and LPS on in vitro permeability using a 3-dimensional cell model after basolateral cell exposure. Furthermore, we assessed the extent to which these mediators in IBS plasma play a role in intestinal barrier function.Materials and MethodsCaco-2 cells were grown in extracellular matrix to develop into polarized spheroids and were exposed to tryptase (10 - 50 mU), LPS (1 - 50 ng/mL) and two-fold diluted plasma samples of 7 patients with IBS-D, 7 with constipation-predominant IBS (IBS-C) and 7 healthy controls (HC). Barrier function was assessed by the flux of FITC-dextran (FD4) using live cell imaging. Furthermore, plasma tryptase and LPS were determined.ResultsTryptase (20 and 50 mU) and LPS (6.25 – 50 ng/mL) significantly increased Caco-2 permeability versus control (all P< 0.05). Plasma of IBS-D only showed significantly elevated median tryptase concentrations (7.1 [3.9 – 11.0] vs. 4.2 [2.2 – 7.0] vs. 4.2 [2.5 – 5.9] μg/mL; P<0.05) and LPS concentrations (3.65 [3.00 – 6.10] vs. 3.10 [2.60-3.80] vs. 2.65 [2.40 – 3.40] EU/ml; P< 0.05) vs. IBS-C and HC. Also, plasma of IBS-D increased Caco-2 permeability versus HC (0.14450 ± 0.00472 vs. 0.00021 ± 0.00003; P < 0.001), which was attenuated by selective inhibition of tryptase and LPS (P< 0.05).ConclusionBasolateral exposure of spheroids to plasma of IBS-D patients resulted in a significantly increased FD4 permeation, which was partially abolished by selective inhibition of tryptase and LPS. These findings point to a role of systemic tryptase and LPS in the epithelial barrier alterations observed in patients with IBS-D.

FODMAP diet modulates visceral nociception by lipopolysaccharide-mediated intestinal inflammation and barrier dysfunction

“…An increased serum LPS concentration has been reported in patients with IBS-D compared with HS (24). Endotoxins, which are a component of the outer membrane of Gram-negative bacteria, stimulate various inflammatory mediators.…”

The Effect of Prim-<i>O</i>-Glucosylcimifugin on Tryptase-Induced Intestinal Barrier Dysfunction in Caco-2 Cells

“…30) TRYP increases the permeability of colon tissue in diarrhea-predominant IBS patients. 31) A study conducted by Ludidi et al revealed that TRYP can increase the permeation flux of 4-kDa fluorescein isothiocyanate-labelled dextran (FD4) in Caco-2 cells, indicating an effect of enhancing paracellular permeability and intestinal barrier dysfunction. 32) In our study, we induced Caco-2 cell monolayers with TRYP, and this treatment reduced the TEER and increased the PFP.…”

Характеристика Состояния Кишечной Микрофлоры И Содержания Короткоцепочечных Жирных Кислот У Больных С Синдромом Раздраженного Кишечника

“…This "competition" is called colonization resistance and is an important guarantee of the normal functioning of the gastrointestinal system. Certain important molecules, which may include short-chain fatty acids (SCFA) and bacteriocins, are implicated in the course of colonization resistance [4].…”

“…SCFA lowers the pH around the intestinal epithelial cells that has a protective effect on them. Besides, SCFA provide antibacterial protection against pathogenic bacteria by attracting neutrophils and cytokines, with immune tolerance to commensal flora remaining [4]. It is believed that different SCFA can have various effects, in particular, butyrate is more present in the intestine, propionate -in the enterohepatic circulation, acetate -in the systemic circulation [4,6].…”