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Mary H Perdue

Publications and source records attributed to Mary H Perdue.

23 records · Page 2Linked to original sources
PubMed2002

Physical and psychological stress in rats enhances colonic epithelial permeability via peripheral CRH.

Stress may be a contributing factor in intestinal inflammatory disease; however, the underlying mechanisms have not been elucidated. We previously reported that acute stress altered jejunal epithelial physiology. In this study, we examined both physical and psychological stress-induced functional changes in colonic mucosa. Colonic mucosal tissue from rats subjected to either 2 hr of cold-restraint stress or 1 hr of water-avoidance stress demonstrated altered ionic transport as well as significantly elevated baseline conductance (ionic permeability) and flux of horseradish peroxidase (macromolecular permeability). Intraperitoneal pretreatment with the corticotropin-releasing hormone (CRH) antagonist, a helical CRH(9-41), inhibited the stress-induced abnormalities, while exogenous intraperitoneal administration of CRH, to control rats, mimicked the stress responses and in vitro CRH increased the macromolecular permeability. These results suggest that peripheral CRH mediates stress-induced colonic pathophysiology. We speculate that a stress-induced barrier defect may allow uptake of immunogenic substances into the colonic mucosa, initiating or exacerbating intestinal inflammation.

Animals↗
PubMed2002

Chronic stress induces mast cell-dependent bacterial adherence and initiates mucosal inflammation in rat intestine.

BACKGROUND & AIMS: Chronic psychological stress is an important factor in relapses of intestinal disorders, but it remains unclear if stress can induce primary gut inflammation in a previously healthy host. METHODS: Mast cell-deficient (Ws/Ws) rats and wild-type control (+/+) rats were submitted to water avoidance stress or sham stress (1 h/day) for 10 consecutive days, as a model of ongoing life stress. RESULTS: Both rat groups had similar systemic responses to stress, as assessed by changes in weight, corticosterone levels, and defecation. In +/+ rats, chronic stress induced barrier dysfunction in the ileum and colon (increased macromolecular permeability and depletion of mucus) and ultrastructural changes in epithelial cells (enlarged mitochondria and presence of autophagosomes) associated with bacterial adhesion and penetration into enterocytes. Moreover, hyperplasia and activation of mast cells, infiltration of neutrophils and mononuclear cells, and increased myeloperoxidase (MPO) activity were documented in the mucosa. In intestine of Ws/Ws rats, epithelial function and morphology were unchanged by chronic stress, bacterial-epithelial cell interaction was not demonstrated, and there was no evidence of inflammatory cell infiltration. CONCLUSIONS: These findings suggest that chronic psychological stress can be an initiating factor in intestinal inflammation by impairing mucosal defenses against luminal bacteria and highlight the importance of mast cells in this process.

Animals↗
PubMed2002

Factors regulating the effect of IL-4 on intestinal epithelial barrier function.

BACKGROUND: Inflammatory bowel disease is associated with an imbalance in cytokine production and defective intestinal barrier function. Previous studies indicate that IL-4, a cytokine increased in food allergy and in early Crohn's disease, enhances epithelial permeability. Here, we characterized the mechanism of action of IL-4 on cultured epithelial cells and examined if the anti-inflammatory cytokines, TGF-beta or IL-10, can modulate the effects of IL-4. METHODS: Confluent monolayers of human T84 epithelial cells were cultured with IL-4 alone or in combination with IL-10 or TGF-beta or with inhibitors of protein synthesis and blockers of IL-4 receptor signalling pathways. Permeability was evaluated by measuring transepithelial resistance (TER), flux of (3)H-fMLP (a small bacterial tripeptide) and horseradish peroxidase (HRP) (a macromolecule). RESULTS: T84 cells cultured with IL-4 showed a significant drop in TER as well as an increased flux of (3)H-fMLP and HRP. Co-treatment with IL-10 did not improve TER, whereas TGF-beta attenuated the resistance drop. However, neither TGF-beta nor IL-10 were able to correct the increased (3)H-fMLP flux. In contrast, the increased HRP flux caused by IL-4 was inhibited by both IL-10 and TGF-beta. TGF-beta and IL-10 significantly reduced IL-4-enhanced values for endosomal area and paracellular spaces containing HRP. Inhibitor studies indicated the requirement for protein synthesis and the involvement of phosphatidylinositol 3-kinase. CONCLUSIONS: These results provide new insights into the regulation of intestinal barrier function and may suggest a novel approach in the treatment of intestinal inflammation.

Biological Transport↗