Ischemia-reperfusion in feline small intestine: a role for nitric oxide

1993 ◽  
Vol 264 (1) ◽  
pp. G143-G149 ◽  
Author(s):  
P. Kubes

The objective of this study was to assess whether nitric oxide synthesis inhibition affects intestinal barrier function after ischemia-reperfusion of the feline small bowel. Local intra-arterial infusion of the nitric oxide synthesis inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 25 nmol.ml-1.min-1) was performed in autoperfused segments of cat ileum for 60 min after 90 min of ischemia and 60 min of reperfusion. Epithelial permeability was quantitated by measuring blood-to-lumen clearance of 51Cr-labeled EDTA, and microvascular dysfunction was assessed by measuring the clearance of protein from the vasculature into the interstitium. 125I-labeled albumin clearance from blood to lumen and histology were performed to further characterize the extent of intestinal dysfunction after reperfusion of the postischemic intestine in the presence and absence of L-NAME. Ischemia-reperfusion-induced mucosal and microvascular permeability increases were dramatically augmented by L-NAME infusion, and this effect was reversed by infusion of L-arginine (125 nmol.ml-1.min-1). Initiating L-arginine (but not D-arginine) infusion alone 10 min before reperfusion provided protection against ischemia-reperfusion-induced mucosal barrier dysfunction; however, this was not associated with a reduction in endogenous levels of L-arginine during ischemia-reperfusion. These data suggest that basal nitric oxide production is important in minimizing mucosal and microvascular barrier dysfunction associated with reperfusion of postischemic intestine.

1993 ◽  
Vol 265 (1) ◽  
pp. G189-G195 ◽  
Author(s):  
D. Payne ◽  
P. Kubes

Recent data have demonstrated that inhibition of nitric oxide synthesis exacerbated the mucosal injury associated with reperfusion of the postischemic intestine. In this study, using a feline 1-h intestinal ischemia followed by reperfusion model, we tested the possibility that exogenous sources of nitric oxide may prevent the reperfusion-induced mucosal barrier disruption and examined the mechanisms involved. Mucosal barrier integrity was assessed by determining 51Cr-EDTA clearance from blood to lumen. Intestinal blood flow and resistance were also determined. Reperfusion after 1 h of ischemia significantly increased 51Cr-EDTA clearance (0.05 +/- 0.01 to 0.35 +/- 0.07 ml.min-1.100 g-1) and decreased intestinal blood flow by 50%. Exogenous sources of nitric oxide including SIN-1, CAS-754, and nitroprusside as well as exogenous L-arginine all reduced reperfusion-induced mucosal barrier dysfunction without improving intestinal blood flow. Inhibition of endogenous nitric oxide with NG-nitro-L-arginine methyl ester between 1 and 2 h of reperfusion further augmented the rise in mucosal permeability associated with ischemia-reperfusion. Addition of the permeable analogue of guanosine 3',5'-cyclic monophosphate, 8-bromoguanosine 3',5'-cyclic monophosphate, improved reperfusion-induced intestinal blood flow significantly but did not provide protection against mucosal barrier disruption associated with the first hour of ischemia-reperfusion. Exogenous sources of nitric oxide can reduce reperfusion-induced mucosal barrier dysfunction independent of alterations in intestinal blood flow.


Nutrients ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2325 ◽  
Author(s):  
Danielle Cardoso-Silva ◽  
Deborah Delbue ◽  
Alice Itzlinger ◽  
Renée Moerkens ◽  
Sebo Withoff ◽  
...  

Gluten-related disorders include distinct disease entities, namely celiac disease, wheat-associated allergy and non-celiac gluten/wheat sensitivity. Despite having in common the contact of the gastrointestinal mucosa with components of wheat and other cereals as a causative factor, these clinical entities have distinct pathophysiological pathways. In celiac disease, a T-cell mediate immune reaction triggered by gluten ingestion is central in the pathogenesis of the enteropathy, while wheat allergy develops as a rapid immunoglobulin E- or non-immunoglobulin E-mediated immune response. In non-celiac wheat sensitivity, classical adaptive immune responses are not involved. Instead, recent research has revealed that an innate immune response to a yet-to-be-defined antigen, as well as the gut microbiota, are pivotal in the development in this disorder. Although impairment of the epithelial barrier has been described in all three clinical conditions, its role as a potential pathogenetic co-factor, specifically in celiac disease and non-celiac wheat sensitivity, is still a matter of investigation. This article gives a short overview of the mucosal barrier of the small intestine, summarizes the aspects of barrier dysfunction observed in all three gluten-related disorders and reviews literature data in favor of a primary involvement of the epithelial barrier in the development of celiac disease and non-celiac wheat sensitivity.


1996 ◽  
Vol 270 (2) ◽  
pp. G225-G237 ◽  
Author(s):  
I. Alican ◽  
P. Kubes

There is growing evidence that endogenous nitric oxide (NO) regulates mucosal barrier integrity under physiological conditions and counters the increase in mucosal permeability associated with acute pathophysiological states. The potential mechanisms of action for the protective effects of NO are discussed. These include maintenance of blood flow, inhibition of platelet and leukocyte adhesion and/or aggregation within the vasculature, modulation of mast cell reactivity, and scavenging of reactive oxygen metabolites such as superoxide. On the basis of the data presented, we conclude that both constitutive nitric oxide synthase (cNOS)-derived endogenous NO and exogenous NO (from NO donors) appear to reduce the sequelae of acute inflammation. The second section of this review summarizes the data germane to prolonged (chronic) inflammatory conditions associated with the overproduction of NO from the inducible form of NOS (iNOS). Some emphasis is placed on the role of NO in sepsis and inflammatory bowel disease (IBD), and data to suggest that NO, or more specifically a NO-derived mediator, is involved in these disorders are summarized. These studies are compared with recent publications suggesting that inhibition of NO synthesis with nonspecific inhibitors of NOS or selective iNOS inhibitors may not protect in models of sepsis or IBD. Overall, the review highlights the potential importance of the type of NOS enzyme involved in the particular inflammatory process being studied.


2001 ◽  
Vol 280 (1) ◽  
pp. G7-G13 ◽  
Author(s):  
Johan D. Söderholm ◽  
Mary H. Perdue

The influence of stress on the clinical course of a number of intestinal diseases is increasingly being recognized, but the underlying mechanisms are largely unknown. This themes article focuses on recent findings related to the effects of stress on mucosal barrier function in the small intestine and colon. Experiments using animal models demonstrate that various types of psychological and physical stress induce dysfunction of the intestinal barrier, resulting in enhanced uptake of potentially noxious material (e.g., antigens, toxins, and other proinflammatory molecules) from the gut lumen. Evidence from several studies indicates that in this process, mucosal mast cells play an important role, possibly activated via neurons releasing corticotropin-releasing hormone and/or acetylcholine. Defining the role of specific cells and mediator molecules in stress-induced barrier dysfunction may provide clues to novel treatments for intestinal disorders.


2020 ◽  
Vol 11 ◽  
Author(s):  
Runze Quan ◽  
Chaoyue Chen ◽  
Wei Yan ◽  
Ying Zhang ◽  
Xi Zhao ◽  
...  

B cell-activating factor (BAFF) production is increased in septic patients. However, the specific role of BAFF in sepsis remains unknown. This study was designed to investigate the expression and function of BAFF in an experimental endotoxemia model and to identify the potential mechanisms. We established an endotoxemia mouse (6–8 weeks, 20–22 g) model by administering 30 mg/kg lipopolysaccharide (LPS). BAFF levels in the circulating system and organ tissues were measured 4 and 8 h after LPS injection. Survival rates in the endotoxemia mice were monitored for 72 h after BAFF blockade. The effects of BAFF blockade on systemic and local inflammation, organ injuries, and intestinal barrier function were also evaluated 4 h after LPS treatment. BAFF production was systemically and locally elevated after LPS challenge. BAFF blockade improved the survival rate, systemic inflammation, and multi-organ injuries. Moreover, BAFF blockade attenuated both intestinal inflammation and impaired intestinal permeability. BAFF blockade upregulated ZO-1 and occludin protein levels via the NF-κB/MLCK/MLC signaling pathway. These results suggested that BAFF blockade protects against lethal endotoxemia at least partially by alleviating inflammation, multi-organ injuries, and improving intestinal barrier function and provides a novel focus for further research on sepsis and experimental evidence for clinical therapy.


Biomedicines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 187
Author(s):  
Lokman Pang ◽  
Jennifer Huynh ◽  
Mariah G. Alorro ◽  
Xia Li ◽  
Matthias Ernst ◽  
...  

The intestinal epithelium provides a barrier against commensal and pathogenic microorganisms. Barrier dysfunction promotes chronic inflammation, which can drive the pathogenesis of inflammatory bowel disease (IBD) and colorectal cancer (CRC). Although the Signal Transducer and Activator of Transcription-3 (STAT3) is overexpressed in both intestinal epithelial cells and immune cells in IBD patients, the role of the interleukin (IL)-6 family of cytokines through the shared IL-6ST/gp130 receptor and its associated STAT3 signalling in intestinal barrier integrity is unclear. We therefore investigated the role of STAT3 in retaining epithelial barrier integrity using dextran sulfate sodium (DSS)-induced colitis in two genetically modified mouse models, to either reduce STAT1/3 activation in response to IL-6 family cytokines with a truncated gp130∆STAT allele (GP130∆STAT/+), or by inducing short hairpin-mediated knockdown of Stat3 (shStat3). Here, we show that mice with reduced STAT3 activity are highly susceptible to DSS-induced colitis. Mechanistically, the IL-6/gp130/STAT3 signalling cascade orchestrates intestinal barrier function by modulating cytokine secretion and promoting epithelial integrity to maintain a defence against bacteria. Our study also identifies a crucial role of STAT3 in controlling intestinal permeability through tight junction proteins. Thus, therapeutically targeting the IL-6/gp130/STAT3 signalling axis to promote barrier function may serve as a treatment strategy for IBD patients.


2019 ◽  
Vol 5 ◽  
pp. 18-30 ◽  
Author(s):  
Jonathan C. Valdez ◽  
Bradley W. Bolling

Chronic intestinal inflammation, occurring in inflammatory bowel diseases (IBD), is associated with compromised intestinal barrier function. Inflammatory cytokines disrupt tight junctions and increase paracellular permeability of luminal antigens. Thus, chronic intestinal barrier dysfunction hinders the resolution of inflammation. Dietary approaches may help mitigate intestinal barrier dysfunction and chronic inflammation. A growing body of work in rodent models of colitis has demonstrated that berry consumption inhibits chronic intestinal inflammation. Berries are a rich dietary source of polyphenolic compounds, particularly anthocyanins. However, berry anthocyanins have limited bioavailability and are extensively metabolized by the gut microbiota and host tissue. This review summarizes the literature regarding the beneficial functions of anthocyanin-rich berries in treating and preventing IBD. Here, we will establish the role of barrier function in the pathogenesis of IBD and how dietary anthocyanins and their known microbial catabolites modulate intestinal barrier function.


2021 ◽  
Author(s):  
Amir Bein ◽  
Cicely W Fadel ◽  
Ben Swenor ◽  
Wuji Cao ◽  
Rani K Powers ◽  
...  

Environmental Enteric Dysfunction (EED) is a chronic inflammatory condition of the intestine characterized by villus blunting, compromised intestinal barrier function, and reduced nutrient absorption. Here, we show that key genotypic and phenotypic features of EED-associated intestinal injury can be reconstituted in a human intestine-on-a-chip (Intestine Chip) microfluidic culture device lined by organoid-derived intestinal epithelial cells from EED patients and cultured in niacinamide- and tryptophan-deficient (-N/-T) medium. Exposure of EED Intestine Chips to -N/-T deficiencies resulted in transcriptional changes similar to those seen in clinical EED patient samples including congruent changes in six of the top ten upregulated genes. Exposure of EED Intestine Chips or chips lined by healthy intestinal epithelium (healthy Intestine Chips) to -N/-T medium resulted in severe villus blunting and barrier dysfunction, as well as impairment of fatty acid uptake and amino acid transport. EED Intestine Chips exhibited reduced secretion of cytokines at baseline, but their production was significantly upregulated compared to healthy Intestine Chips when exposed to -N/-T deficiencies. The human Intestine Chip model of EED-associated intestinal injury may be useful for analyzing the molecular, genetic, and nutritional basis of this disease and can serve as a preclinical model for testing potential EED therapeutics.


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