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Objective: With the number of patients with acute pancreatitis (AP) increasing year by year, it is pressing to explore new key genes and markers for the treatment of AP. miR-455-3p/solute carrier family 2 member 1 (Slc2a1) obtained through bioinformatics analysis may participate in the progression of AP., Materials and Methods: The C57BL/6 mouse model of AP was constructed for subsequent studies. Through bioinformatics analysis, the differentially expressed genes related to AP were screened and hub genes were identified. A caerulein-induced AP animal model was constructed to detect the pathological changes of mouse pancreas by HE staining. The concentrations of amylase and lipase were measured. Primary mouse pancreatic acinar cells were isolated and subjected to microscopy to observe their morphology. The enzymatic activities of trypsin and amylase were detected. The secretion of inflammatory cytokines in mouse were measured with the ELISA kits of TNF- α , IL-6 and IL-1 β to determine pancreatic acinar cell damage. A binding site between the Slc2a1 3' UTR region and the miR-455-3p sequence was verified by dual-luciferase reporter assay. The expression of miR-455-3p was quantified by qRT-PCR, and Slc2a1 were detected by western blot., Results: A total of five (Fyn, Gadd45a, Sdc1, Slc2a1, and Src) were identified by bioinformatics analysis, and miR-455-3p/Slc2a1 were further studied. HE staining results showed that the AP models were successfully established by caerulein induction. In mice with AP, the expression of miR-455-3p was reduced, while that of Slc2a1 was increased. In the caerulein-induced cell model, the expression of Slc2a1 was significantly reduced after intervention of miR-455-3p mimics, whereas increased after miR-455-3p inhibitor treatment. miR-455-3p decreased the secretion of inflammatory cytokines in the cell supernatant, reduced the activity of trypsin and amylase, and alleviated the cell damage induced by caerulein. In addition, Slc2a1 3'UTR region was bound by miR-455-3p, and its protein expression was also regulated., Conclusion: miR-455-3p alleviated caerulein-induced mouse pancreatic acinar cell damage by regulating the expression of Slc2a1., Competing Interests: The authors declare there are no competing interests., (©2023 Zhan et al.)

Background & Aims: Pancreatitis is characterized by acinar cell death and persistent inflammation. Ferroptosis is a type of lipid peroxidation-dependent necrosis, which is negatively regulated by glutathione peroxidase 4. We studied how trypsin, a serine protease secreted by pancreatic acinar cells, affects the contribution of ferroptosis to triggering pancreatitis., Methods: In vitro, the mouse pancreatic acinar cell line 266-6 and mouse primary pancreatic acinar cells were used to investigate the effect of exogenous trypsin on ferroptosis sensitivity. Short hairpin RNAs were designed to silence gene expression, whereas a library of 1080 approved drugs was used to identify new ferroptosis inhibitors in 266-6 cells. In vivo, a Cre/LoxP system was used to generate mice with a pancreas-specific knockout of Gpx4 (Pdx1-Cre;Gpx4 flox/flox mice). Acute or chronic pancreatitis was induced in these mice (Gpx4 flox/flox mice served as controls) by cerulein injections or a Lieber-DeCarli alcoholic liquid diet. Pancreatic tissues, acinar cells, and serum were collected and analyzed by histology, immunoblot, quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, or immunohistochemical analyses., Results: Supraphysiological doses of trypsin (500 or 1000 ng/mL) alone did not trigger significant cell death in 266-6 cells and mouse primary pancreatic acinar cells, but did increase the sensitivity of these cells to ferroptosis upon treatment with cerulein, L-arginine, alcohol, erastin, or RSL3. Proteasome 26S subunit, non-adenosine triphosphatase 4-dependent lipid peroxidation caused ferroptosis in pancreatic acinar cells by promoting the proteasomal degradation of glutathione peroxidase 4. The drug screening campaign identified the antipsychotic drug olanzapine as an antioxidant inhibiting ferroptosis in pancreatic acinar cells. Mice lacking pancreatic Gpx4 developed more severe pancreatitis after cerulein infection or ethanol feeding than control mice. Conversely, olanzapine administration protected against pancreatic ferroptotic damage and experimental pancreatitis in Gpx4-deficient mice., Conclusions: Trypsin-mediated sensitization to ferroptotic damage increases the severity of pancreatitis in mice, and this process can be reversed by olanzapine., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Previously we have shown that trypsin, a protein typically involved in digestion, is released from gills of both fresh and saltwater fishes into surrounding water under stress or injury. We have also shown that each species produces trypsin with different specific activities. In this report, using zebrafish as a model, we identified that trypsin induces an aversive response in zebrafish larvae and adult zebrafish. Since Protease-Activated Receptor 2 (PAR2) responds to trypsin, we tested whether the aversive response is dependent on the activation of PAR2 located on the zebrafish skin cells. Zebrafish larvae treated separately with neomycin and zinc sulfate also showed aversive response indicating neuromast, and olfactory cells are not involved in this aversion. Cultured keratinocytes from zebrafish showed a response to trypsin. Zebrafish larvae subjected to knockdown of par2a also exhibited reduced escape response. Similarly, par2a-deficient mutant larvae displayed no response to trypsin. Since it has been shown that stress activates PAR2 and sends signals to the brain as shown by the increased c-fos expression, we tested c-fos expression in adult zebrafish brains after trypsin treatment of adults and found enhanced c-fos expression by qRT-PCR. Taken together, our results show that the trypsin activates PAR2 on keratinocytes signaling the brain, and this pathway of trypsin-induced escape response will provide a unique communication mechanism in zebrafish. Furthermore, since PAR2 activation also occurs in pain/pruritus sensing, this model might be useful in elucidating components of signaling pathways in pain/pruritus., Competing Interests: The authors have declared that no competing interests exist.

Celiac disease (CD) is a chronic immune-mediated disorder, characterized by enhanced paracellular permeability across the intestinal epithelium. The complex system of intercellular junctions, including tight junctions (TJs) and adherens junctions (AJs), seals together the epithelial cells to form a continuous layer. The improvements in barrier integrity have been related to modifications in intercellular junction protein expression. Polyamines (spermidine, spermine, and putrescine) actively participate in the modulation of the AJ expression. Both in vitro and in vivo studies have demonstrated that also probiotics can promote the integrity and the function of the intestinal barrier. On these bases, the present work investigated the protective effects exerted by Lactobacillus rhamnosus GG (L.GG) against the pepsin-trypsin-digested gliadin (PTG)-induced enteropathy in jejunal tissue samples of Wistar rats. In particular, the probiotic effects have been evaluated on the intestinal mucosal architecture, polyamine metabolism and intercellular junction protein expression (ZO-1, Occludin, Claudin-1, β-catenin and E-cadherin). The results from this study indicate that L.GG protects the intestinal mucosa of rats from PTG-induced damage, by preventing the reduction of the expression of the intercellular junction proteins. Consequently, a role for L.GG in the therapeutic management of the gluten-related disorders in humans could be hypothesized.

Interpretation on the effectiveness of potential substances to enhance skeletal muscle regeneration is difficult if an inappropriate vehicle is administered, since vehicle administration can directly enhance or suppress regenerative capacity. In the current study, intramuscular administration of lipid-soluble and water-soluble vehicles into regenerating muscle at the distinct phases of skeletal muscle regeneration (regenerative vs. remodeling) were investigated. Tested vehicles included lipid-soluble [olive oil, (0.1, 1, 5, and 40%) dimethyl sulfoxide (DMSO), and 40% propylene glycol (PG)] and water-soluble [0.9% NaCl, PBS, 0.1% ethanol, and distilled water]. Skeletal muscle regeneration was induced by 1.2% BaCl 2 injection to the tibialis anterior muscle of 10-week-old C57BL/6 male mice. Histological features, skeletal muscle stem cell activity, regenerating muscle fiber formation, angiogenesis, extracellular matrix remodeling, and macrophage infiltration were examined. The results revealed repeated administration of 40% DMSO and 40% PG causes significant recurrent muscle injury, which is pronounced during the remodeling phase compared to the regenerative phase. These findings were supported by (1) massive infiltration of F4/80 + macrophages; (2) significant increase of skeletal muscle stem cell re-activation and nascent regenerating muscle fiber formation; (3) excess fibrous formation; and (4) decreased regenerating muscle fiber cross-sectional area. These deleterious effects were comparable to 2% trypsin (degenerative substance) administration and less pronounced with a single administration. Nevertheless, recurrent muscle injury was still presented with 5% DMSO administration but it can be alleviated when 0.1% DMSO was administered during the remodeling phase. In contrast, none of the tested vehicles enhanced regenerative capacity compared with IGF-1 administration. Altogether, intramuscular administration of vehicle containing high concentration of DMSO or PG could impair skeletal muscle regenerative capacity and potentially affect validation of the investigational substance.

Introduction: Vigorous and prolonged exercise such as marathon running increases inflammatory markers and the risk of upper respiratory illness (URI) in athletes. Nutritional supplements are being tested as countermeasures of exercise-induced inflammation and immune dysfunction., Methods: In this prospective randomized, double-blind, placebo-controlled phase I trial, healthy male runners (N = 138, age 42 ± 11 yr) were supplemented with rutoside (600-1200 mg·d) and hydrolytic enzymes (540-1080 mg·d bromelain, 288-576 mg·d trypsin) (WOB) or placebo (PL) for 1 wk before and 2 wk after the Munich Marathon 2013. Blood samples were collected 5 wk prerace and immediately, 24 h, and 72 h postrace and analyzed for inflammation biomarkers (interleukins [IL] 6 and 10, high-sensitivity C-reactive protein, and leukocytes). URI rates, assessed by the Wisconsin Upper Respiratory Symptom Survey, were compared between the study groups during the 2-wk period after the marathon race. URI was defined if the Wisconsin Upper Respiratory Symptom Survey score was equal or greater than seven, representing either one severe symptom or seven mild symptoms., Results: Immediately postrace, the increase of IL-6 was not significantly different between the WOB and the PL groups (median [interquartile range]: WOB, 33.8 [22.5-58.8] ng·L; PL, 35.6 [24.8-61.29] ng·L; P = 0.758). No significant group differences were observed for increases of IL-10, high-sensitivity C-reactive protein, or leukocytes pre- to postrace (all P > 0.05). From race day until 2 wk after the marathon race, the percentage of individuals with at least one URI did not significantly differ between the groups (WOB, 50.0%; PL, 51.5%; P = 0.859)., Conclusion: Supplementation with rutoside and hydrolytic enzymes before and after a marathon race did not attenuate postrace inflammation or decrease URI incidence in nonelite male marathon runners.

The use of systemic enzyme therapy in combination with antibiotics in the treatment of urogenital chlamydia infection in patients of both sexes proved to improve the therapeutic efficacy and to reduce the risk of the side effects.

Active thrombin is found in the airways of patients with a variety of inflammatory lung diseases. However, whether thrombin contributes to the pathologies of these diseases is unknown, although thrombin is a potent inflammatory mediator in other organ systems. In the present study we have assessed the acute inflammatory effect of inhaled thrombin and investigated the possible receptors mediating any effects in mice. Thrombin (200-2000 U kg(-1) intranasally), induced the recruitment of a small, but significant, number of neutrophils into the airways as assessed by differential counts of cells retrieved by bronchoalveolar lavage (BAL). This small response was mimicked by peptide agonists of proteinase-activated receptor-4 (PAR(4); GYPGKF, AYPGKF; 2-20 mg kg(-1)), but not PAR(1) (SFLLRN; 2-20 mg kg(-1)). By contrast, trypsin (200-2000 U kg(-1)) caused profound inflammation and lung damage. Concentrations of tumour necrosis factor-alpha (TNF-alpha) were elevated in BAL fluid from thrombin-treated mice, and a TNF-alpha-neutralising antibody inhibited the influx of neutrophils in response to thrombin. Although isolated alveolar macrophages appeared to express PAR(1)- and PAR(4)-immunoreactivity, these cells failed to release TNF-alpha above baseline levels in response to thrombin, trypsin or any of the peptide PAR agonists. Neither thrombin (2000 U kg(-1)) nor trypsin (200 U kg(-1)) modified the airway neutrophilia in response to intranasal bacterial lipopolysaccharide (LPS; 100 micrograms kg(-1)). In conclusion, exogenous thrombin has only a modest acute inflammatory action in the lung that appears to be mediated by PAR(4) and involve release of TNF-alpha from an unknown source.

Objective: To compare the effectiveness and safety of the triple combination Phlogenzym (rutoside, bromelain, and trypsin) with double combinations, the single substances, and placebo., Design: Multinational, multicentre, double blind, randomised, parallel group design with eight groups structured according to a factorial design., Setting: Orthopaedic surgery and emergency departments in 27 European hospitals., Participants: A total of 721 patients aged 16-53 years presenting with acute unilateral sprain of the lateral ankle joint. PRIMARY EFFICACY CRITERIA: (a) Pain on walking one or two steps, as defined by the patient on a visual analogue scale. (b) The range of motion, as measured by the investigator and expressed as a sum of flexion and extension. (c) The volume of the injured ankle measured with a volometer., Results: At the primary end point at seven days, the greatest reduction in pain was in the bromelain/trypsin group (73.7%). The Phlogenzym group showed a median reduction of 60.3%, and the placebo group showed a median reduction of 73.3%. The largest increase in range of motion (median) was in the placebo group (60% change from baseline). The Phlogenzym group showed a median increase of 42.9%. The biggest decrease in swelling was in the trypsin group (3.9% change from baseline). The Phlogenzym group showed a -2.30% change from baseline and the placebo group a -2.90% change. In the subgroup analysis of patients who did not use a Caligamed brace, Phlogenzym was superior to placebo for the summarising directional test of the primary efficacy criteria (MW = 0.621; LB-CI 0.496; p = 0.029; one sided Wei-Lachin procedure). The vast majority of doctors and patients rated the tolerability of all treatments tested as very good or at least good., Conclusions: Phlogenzym was not found to be superior to the three two-drug combinations, the three single substances, or placebo for treatment of patients with acute unilateral sprain of the lateral ankle joint. The small subgroup of patients treated without the support of a Caligamed brace showed evidence of superiority of Phlogenzym over placebo. Further research is warranted to study this effect of Phlogenzym in patients treated without ankle support.

Eight weeks after a single intravenous injection of trypsin, more than half of 26 treated rats showed pulmonary emphysema, as demonstrated by a significant increase of the mean linear intercept (MLI = 107 microns) in comparison with 11 controls (69 +/- 15 microns) (mean +/- SD). As observed 56 days after the injection, the intraperitoneal administration of trypsin (24 rats) also leads to lung emphysema (MLI = 101-106 microns), as does endotracheal instillation of elastase (13 rats), (MLI = 108 microns). The intraperitoneal administration of trypsin in animals constitutes a model close to human pathology with which lung alterations in acute pancreatitis may be studied. Having no elastolytic properties, trypsin cannot directly induce emphysema. The observation of a pulmonary leucostasis in eight rats sacrificed early after the trypsin injection suggested that leucocyte trapping and activation are important for the genesis of this trypsin-triggered emphysema.

Esophagitis is now recognized to occur in the absence of gastric acid. We have compared the potentially injurious effect of physiologic concentrations of trypsin, taurodeoxycholate, and pepsin at pH 7.5 using a continuously perfused rabbit esophagus model. Gross and microscopic esophagitis, tissue hemorrhage, and indexes of esophageal mucosal barrier function were assessed. Trypsin caused the most severe morphologic changes and hemorrhage, but only minimal disruption of the esophageal mucosal barrier. In contrast, taurodeoxycholate caused only minimal esophagitis and no hemorrhage, but caused extensive disruption of the esophageal mucosal barrier. Neither pepsin, at this alkaline pH, nor alkaline test solution alone (pH 7.5) caused esophageal injury by any criteria. These results show that the degree of esophageal mucosal barrier disruption cannot always be equated with the degree of morphologic injury, and that different components of the gastroduodenal contents may differ in their sites or mechanisms of esophageal injury. Finally, among the gastroduodenal contents we tested, trypsin was the most noxious agent in alkaline reflux esophagitis in terms of causing mucosal erosion, inflammation, and hemorrhage.