Laryngeal and Esophageal Mucosal Protection Using the Angico Gum Biopolymer in a Mouse Model of Reflux.

OBJECTIVE: This study aimed to evaluate the in vivo protective effect of the angico gum biopolymer in reducing the inflammatory response and preserving the integrity of the laryngeal and esophageal mucosa. STUDY DESIGN: Animal study. METHODS: A murine surgical model of gastroesophageal reflux disease was accomplished and subsequently treated with angico gum or omeprazole. On days 3 and 7 post surgery, samples of the larynx and esophagus, respectively, were collected to measure the level of inflammation (wet weight and myeloperoxidase activity) and mucosal integrity (transepithelial electrical resistance and mucosal permeability to fluorescein). RESULTS: Angico gum and omeprazole decreased laryngeal inflammation (wet weight and myeloperoxidase activity) and dramatically improved the integrity of the laryngeal mucosa. It also reduced inflammation (decreased wet weight and myeloperoxidase activity) of the esophagus and preserved the barrier function (inferred by assessing the integrity of the mucosa). CONCLUSION: This study demonstrates the protective effect of angico gum in an experimental gastroesophageal reflux disease model. Angico gum attenuates inflammation and impairment of the mucosal barrier function not only in the larynx but also in the esophagus. LEVEL OF EVIDENCE: NA Laryngoscope, 133:162-168, 2023.

McN-A-343, a muscarinic agonist, reduces inflammation and oxidative stress in an experimental model of ulcerative colitis.

AIM: The aim of the present study was to investigate the anti-inflammatory response mediated of the M1 muscarinic acetylcholine receptor (mAChR) during experimental colitis. MATERIAL AND METHODS: After the induction of 6% acetic acid colitis, mice were treated with McN-A-343 0.5, 1.0, and 1.5 mg/kg or dexamethasone (DEXA, 2.0 mg/kg) or pirenzepine (PIR, 10 mg/kg; M1 mAChR antagonist). Colonic inflammation was assessed by macroscopic and microscopic lesion scores, colonic wet weight, myeloperoxidase (MPO) activity, interleukin-1 beta (IL1-ß) levels and tumor necrosis factor alpha (TNF-α), glutathione (GSH), malondialdehyde (MDA) and nitrate and nitrite (NO3/NO2), mRNA expression of IKKα, nuclear factor kappa beta (NF-kB) and cyclooxygenase-2 (COX-2), as well protein expression of NF-kB and COX-2. RESULTS: Treatment with McN-A-343 at a concentration of 1.5 mg/kg showed a significant reduction in intestinal damage as well as a decrease in wet weight, MPO activity, pro-inflammatory cytokine concentration, markers of oxidative stress and expression of inflammatory mediators. The action of the M1 agonist by the administration of pirenzepine, which promoted the blocking of the mAChR M1-mediated anti-inflammatory response, has also been proven. CONCLUSION: The results suggest that peripheral colonic M1 mAChR is involved in reversing the pro-inflammatory effect of experimentally induced colitis, which may represent a promising therapeutic alternative for patients with ulcerative colitis.

Polysaccharide from Gracilaria caudata protects the human esophageal mucosal barrier: A differential topical effect and structural dependence.

This study aimed to evaluate the in vitro protective effect of topical treatment with a native sulfated polysaccharide of G. caudata (SP-Gc), hydrolyzed (H-SP-Gc), or desulfated (D-SP-Gc) polysaccharide of Gracilaria caudata in esophageal biopsies obtained from GERD patients. Biopsies were obtained from nonerosive reflux disease (NERD) patients and from erosive esophagitis patients. Then, the biopsies were mounted in an Ussing chamber to measure the basal transepithelial electrical resistance (TEER). The effect of mucosal exposure to an acid solution on TEER was analyzed with or without different concentrations (1, 0.3 or 1%) of SP-Gc, H-SP-Gc, or D-SP-Gc, precoated on the mucosa. Basal esophageal mucosal electrical resistance was significantly lower in erosive esophagitis than from NERD. Mucosal samples precoated with native SP-Gc (1%) significantly prevented TEER drop induced by an acidic solution in NERD, but this effect was not observed in erosive esophagitis. Topical application of D-SP-Gc showed no difference compared to native SP-Gc. However, when treated with chemically-modified SP-Gc, the protective effect observed with native SP-Gc was lost. The present study indicated that SP-Gc protects the human esophageal mucosal barrier in NERD patients. This effect is dependent on the structure but is independent of the presence of sulfate.