Lung and intestine: a specific link in an ulcerative colitis rat model. Gastroenterol Res Pract. 2013;2013:124530. [PMID: 23606829 DOI: 10.1155/2013/124530]

Pneumococcal pep27-mutant inhibits Wnt5a expression via the regulation of T helper cells to attenuate colitis

Inflammatory bowel disease (IBD) is a chronic gut inflammatory disease characterized by extensive colitis and remission of the symptoms. The incidence rate and prevalence of IBD are increasing worldwide; IBD affects millions of people, has poorly defined etiology, and often results in a failure of pharmacological interventions. Regardless of the cause, mucosal healing is indispensable for the regeneration of inflamed mucosa to ensure intestinal homeostasis. Intranasal immunization with the pneumococcal pep27 mutant (Δpep27) has been reported as an avirulent and live vaccine that has been proposed to suppress immune-regulated disorders, eliciting long-lasting immunity. The dose-dependent activity of Δpep27 in the lungs was measured by transcriptome analysis to investigate the long-lasting immunogenic response against IBD. Novel therapeutic targets based on the modulation of Wnt signaling and T regulatory cells interconnected with other signaling cascades in the context of IBD were investigated by qPCR and immunoblotting. M1/M2 macrophages were quantified by FACS analysis. Dextran sulfate sodium-induced colitis induced significant upregulation of Th2 and Th17 as well as noncanonical Wnt5, which subsequently inhibited regulatory T (Treg) expression. In contrast, Δpep27 immunization significantly attenuated the levels of Wnt5, proinflammatory cytokines, oxidative stress parameters, and infiltration of inflammatory cells and enhanced barrier integrity via T helper cell homeostasis and upregulation of M2 macrophages. The data of the present study suggested that Δpep27-elicited Tregs were able to repress Wnt5a expression, assisting with the restoration of immunological tolerance and providing a robust regenerative and antioxidant milieu.

Pathophysiological Concepts and Management of Pulmonary Manifestation of Pediatric Inflammatory Bowel Disease

Pulmonary manifestation (PM) of inflammatory bowel disease (IBD) in children is a rare condition. The exact pathogenesis is still unclear, but several explanatory concepts were postulated and several case reports in children were published. We performed a systematic Medline search between April 1976 and April 2022. Different pathophysiological concepts were identified, including the shared embryological origin, “miss-homing” of intestinal based neutrophils and T lymphocytes, inflammatory triggering via certain molecules (tripeptide proline-glycine-proline, interleukin 25), genetic factors and alterations in the microbiome. Most pediatric IBD patients with PM are asymptomatic, but can show alterations in pulmonary function tests and breathing tests. In children, the pulmonary parenchyma is more affected than the airways, leading histologically mainly to organizing pneumonia. Medication-associated lung injury has to be considered in pulmonary symptomatic pediatric IBD patients treated with certain agents (i.e., mesalamine, sulfasalazine or infliximab). Furthermore, the risk of pulmonary embolism is generally increased in pediatric IBD patients. The initial treatment of PM is based on corticosteroids, either inhaled for the larger airways or systemic for smaller airways and parenchymal disease. In summary, this review article summarizes the current knowledge about PM in pediatric IBD patients, focusing on pathophysiological and clinical aspects.

Biodistribution of andrographolide to assess the interior-exterior relationship between the lung and intestine using microPET

Background

One classic traditional Chinese medicine theory is that the “lung and intestine are exterior‐interiorly related”; however, this has not been confirmed experimentally. The aim of this study was to provide a biological basis for the theory by measuring the tissue distribution of andrographolide.

Methods

Acute pneumonia was induced in a mouse model by repeated stimulation with lipopolysaccharide. The distribution of andrographolide in mice was observed by positron emission tomography (PET) imaging with [¹⁸F]‐labeled andrographolide, and changes in the in vivo distribution before and after modeling were compared. Subsequently, the consistency of pathological changes in lung and intestine was confirmed by observation of pathological sections. Finally, the results were verified by cytokine detection.

Results

The value of organ uptake, pathological changes and inflammatory factor expression of the lung and intestine were consistent. The concentration of andrographolide in the lung and intestine increased significantly, and was confirmed by pathology and enzyme‐linked immunosorbent assays (ELISA).

Conclusions

Micro‐positron emission tomography (microPET) can be used to visually observe the distribution of medicinal ingredients in vivo, and [¹⁸F]‐andrographolide can be used as a tool to assess the interior‐exterior relationship between the lung and intestine.

Baicalin Is Curative Against Rotavirus Damp Heat Diarrhea by Tuning Colonic Mucosal Barrier and Lung Immune Function

BACKGROUND

Previous studies have indicated that rotavirus (RV) is a causative factor for diarrhea and gastroenteritis in pediatric and neonatal settings. Baicalin has many functions, including antibacterial, antiinflammatory, and antihypertensive activities. However, the immunological mechanism of RV-induced diarrhea with heat-dampness syndrome (RV-DH) remains unclear.

AIMS

The aim of this study is to explore the role of baicalin in RV-DH diarrhea and its underlying mechanism.

METHODS

A mouse model of pediatric RV-DH diarrhea was established and treated with baicalin. The concentrations of cytokines were detected by enzyme-linked immunosorbent assay. Messenger RNA (mRNA) expression levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR), while protein expression levels were determined by Western blotting and immunohistochemistry. Flow cytometry was used to detect the frequency of lymphocytes.

RESULTS

The concentrations of interleukin-1β (IL-1β), IL-2, IL-6, IL-8, RVvb, and secretory immunoglobulin A (SIgA) in bronchoalveolar lavage fluid (BALF) and colonic mucosa were significantly increased in the RV-DH group. Decreased expression of occludin, claudin-1, and zonula occludens-1 (ZO-1) indicated loss of tight junction function and disturbances in intestinal mucosal permeability in the RV-DH group. Flow cytometry analysis showed a high rate of CD8⁺ lymphocytes and low amount of CD4⁺ lymphocytes in the RV-DH group. Treatment of RV-DH mice with baicalin significantly reduced the duration of diarrhea and ameliorated the symptoms and pathological and immunological changes. Furthermore, baicalin inhibited STAT1 and activated STAT3 signaling pathways.

CONCLUSIONS

These findings indicate the curative and immunoregulatory properties of baicalin and have direct practical and clinical relevance for the treatment of RV-DH enteritis in humans.

Platelet activating factor receptor regulates colitis-induced pulmonary inflammation through the NLRP3 inflammasome

Extra-intestinal manifestations (EIM) are common in inflammatory bowel disease (IBD). One such EIM is sub-clinical pulmonary inflammation, which occurs in up to 50% of IBD patients. In animal models of colitis, pulmonary inflammation is driven by neutrophilic infiltrations, primarily in response to the systemic bacteraemia and increased bacterial load in the lungs. Platelet activating factor receptor (PAFR) plays a critical role in regulating pulmonary responses to infection in conditions, such as chronic obstructive pulmonary disease and asthma. We investigated the role of PAFR in pulmonary EIMs of IBD, using dextran sulfate sodium (DSS) and anti-CD40 murine models of colitis. Both models induced neutrophilic inflammation, with increased TNF and IL-1β levels, bacterial load and PAFR protein expression in mouse lungs. Antagonism of PAFR decreased lung neutrophilia, TNF, and IL-1β in an NLRP3 inflammasome-dependent manner. Lipopolysaccharide from phosphorylcholine (ChoP)-positive bacteria induced NLRP3 and caspase-1 proteins in human alveolar epithelial cells, however antagonism of PAFR prevented NLRP3 activation by ChoP. Amoxicillin reduced bacterial populations in the lungs and reduced NLRP3 inflammasome protein levels, but did not reduce PAFR. These data suggest a role for PAFR in microbial pattern recognition and NLRP3 inflammasome signaling in the lung.

Pulmonary Aspergillus fumigatus infection in rats affects gastrointestinal homeostasis

Microbiota inhabiting mucosal tissues is involved in maintenance of their immune homeostasis. Growing body of evidence indicate that dysbiosis in gut influence immune responses at distal sites including lungs. There are also reports concerning gut involvement with pulmonary injury/inflammation in settings of respiratory viral and bacterial infections. The impact of infections with other microorganisms on gut homeostasis is not explored. In this study, the rat model of sublethal pulmonary infection with Aspergillus fumigatus was used to investigate the effect of fungal respiratory infection on gut immune-mediated homeostasis. Signs of intestinal damage, intestinal and gut-draining lymphoid tissue cytokine responses and gut bacterial microbiota diversity were examined. Intestinal injury, inflammatory cell infiltration, as well as increased levels of intestinal interferon-γ (IFN-γ) and interleukin-17 (IL-17) (as opposed to unchanged levels of anti-inflammatory cytokine IL-10) during the two-week period depict intestinal inflammation in rats with pulmonary A. fumigatus infection. It could not be ascribed to the fungus as it was not detected in the intestine of infected rats. Increased production of pro-inflammatory cytokines by major gut-draining mesenteric lymph nodes point to these lymphoid organs as places of generation of cytokine-producing cells. No changes in spleen or systemic cytokine responses was observed, showing lack of the effects of pulmonary A. fumigatus infection outside mucosal immune system. Drop of intestinal bacterial microbiota diversity (disappearance of several bacterial bands) was noted early in infection with normalization starting from day seven. From day three, appearance of new bacterial bands (unique to infected individuals, not present in controls) was seen, and some of them are pathogens. Alterations in intestinal bacterial community might have affected intestinal immune tolerance contributing to inflammation. Disruption of gut homeostasis during pulmonary infection might render gastrointestinal tract more susceptible to variety of physiological and pathological stimuli. Data which showed for the first time gut involvement with pulmonary infection with A. fumigatus provide the baseline for future studies of the impact of fungal lung infections to gut homeostasis, particularly in individuals susceptible to these infections.

The Anti-Inflammatory Effect and Intestinal Barrier Protection of HU210 Differentially Depend on TLR4 Signaling in Dextran Sulfate Sodium-Induced Murine Colitis

BACKGROUND

Ulcerative colitis (UC) is strongly associated with inflammation and intestinal barrier disorder. The nonselective cannabinoid receptor agonist HU210 has been shown to ameliorate inflamed colon in colitis, but its effects on intestinal barrier function and extraintestinal inflammation are unclear.

AIMS

To investigate the effects and the underlying mechanism of HU210 action on the UC in relation to a role of TLR4 and MAP kinase signaling.

METHODS

Wild-type (WT) and TLR4 knockout (Tlr4 ^-/-) mice were exposed to 4% dextran sulfate sodium (DSS) for 7 days. The effects of HU210 on inflammation and intestinal barrier were explored.

RESULTS

Upon DSS challenge, mice suffered from bloody stool, colon shortening, intestinal mucosa edema, pro-inflammatory cytokine increase and intestinal barrier destruction with goblet cell depletion, increased intestinal microflora accompanied with elevated plasma lipopolysaccharide, reduced mRNA expression of the intestinal tight junction proteins, and abnormal ratio of CD4⁺/CD8⁺ T cells in the intestinal Peyer's patches. Pro-inflammatory cytokines in the plasma and the lung, as well as pulmonary myeloperoxidase activity, indicators of extraintestinal inflammation were increased. Protein expression of p38α and pp38 was up-regulated in the colon of WT mice. Tlr4 ^-/- mice showed milder colitis. HU210 reversed the intestinal barrier changes in both strains of mice, but alleviated inflammation only in WT mice.

CONCLUSIONS

Our study indicates that in experimental colitis, HU210 displays a protective effect on the intestinal barrier function independently of the TLR4 signaling pathway; however, in the extraintestinal tissues, the anti-inflammatory action seems through affecting TLR4-mediated p38 mitogen-activated protein kinase pathway.

Lung-gut cross-talk: evidence, mechanisms and implications for the mucosal inflammatory diseases

The mucosal immune system (including airway, intestinal, oral and cervical epithelium) is an integrated network of tissues, cells and effector molecules that protect the host from environmental insults and infections at mucous membrane surfaces. Dysregulation of immunity at mucosal surfaces is thought to be responsible for the alarming global increase in mucosal inflammatory diseases such as those affecting the gastrointestinal (Crohn's disease, ulcerative colitis and irritable bowel syndrome) and respiratory (asthma, allergy and chronic obstructive pulmonary disorder) system. Although immune regulation has been well-studied in isolated mucosal sites, the extent of the immune interaction between anatomically distant mucosal sites has been mostly circumstantial and the focus of much debate. With novel technology and more precise tools to examine histological and functional changes in tissues, today there is increased appreciation of the 'common mucosal immunological system' originally proposed by Bienenstock nearly 40 years ago. Evidence is amounting which shows that stimulation of one mucosal compartment can directly and significantly impact distant mucosal site, however the mechanisms are unknown. Today, we are only beginning to understand the complexity of relationships and communications that exist between different mucosal compartments. A holistic approach to studying the mucosal immune system as an integrated global organ is imperative for future advances in understanding mucosal immunology and for future treatment of chronic diseases. In this review, we particularly focus on the latest evidence and the mechanisms operational in driving the lung-gut cross-talk.

Original Research: Extract of Bambusae Caulis in Taeniam inhibits cigarette smoke-induced pulmonary and intestinal inflammation

The pulmonary and intestinal systems have several characteristics in common. It is believed that these similarities somehow function to cause pulmonary-intestinal crosstalk during inflammation. Many studies have shown that pulmonary disease occurs in association with inflammatory bowel disease more often than is commonly recognized. Bambusae Caulis in Taeniam, a medicinal herb originated from the inner bark of Phyllostachys nigra var. henosis (Milford) Rendle (Poaceae), has been used to cure fever, diarrhea, and chest inflammation in Korea as well as in China. Cigarette smoke is a well-known risk factor for several inflammatory disorders. In this study, we induced pulmonary and bowel inflammation in mice using cigarette smoke and investigated whether Bambusae Caulis in Taeniam extract modulates the inflammatory response in both the lung and the bowel. C57BL/6 mice were exposed to cigarette smoke for 90 min per day for three weeks, and Bambusae Caulis in Taeniam extract was administered via oral injection 2 h before cigarette smoke exposure. The bronchoalveolar lavage cells were counted and hematoxylin and eosin staining were performed. Levels of inflammatory mediators in lung and large intestine were determined by enzyme-linked immunosorbent assay, real-time polymerase chain reaction, and Western blotting. Our results showed that Bambusae Caulis in Taeniam attenuated cigarette smoke-induced inflammatory response in both the lung and the bowel of mice by inhibiting the production of pro-inflammatory cytokines, chemokines, and protease as well as NF-κB signaling factor. Therefore, we suggest that Bambusae Caulis in Taeniam extract might be a candidate therapeutic agent for inhibiting pulmonary and intestinal inflammation.

Relationship between Ulcerative Colitis and Lung Injuries

OBJECTIVE

To explore the relationship between ulcerative colitis (UC) and lung injuries by assessing their clinical manifestations and characteristics.

METHODS

From July 2009 to April 2012, 91 UC patients presenting to Longhua Hospital who met the established inclusion and exclusion criteria were enrolled in this retrospective study. According to the scores of disease activity index, the patients were divided into the mild, moderate, and severe groups. Meanwhile, the records of pulmonary symptoms, chest X-ray image, and pulmonary function were reviewed.

RESULTS

Sixty-eight (74.7%) patients had at least 1 pulmonary symptom, such as cough (38.5%), shortness of breath (27.5%), and expectoration (17.6%). And 77 (84.6%) had at least 1 ventilation abnormality. Vital capacity value was significantly lower in the severe group than that in the mild group (91.82%±10.38% vs. 98.92%±12.12%, P<0.05).

CONCLUSIONS

Lung injury is a common extraintestinal complication of UC. According to the theory in Traditional Chinese Medicine that the lung and large intestine are related, both the lungs and large intestine should be treated simultaneously.

Effect of compound dracorhodin enema on pulmonary and colonic expression of interleukin-6 in mice with distal ulcerative colitis

AIM: To investigate the protective effect of compound dracorhodin enema on the lung and intestine of mice with distal ulcerative colitis (UC).

METHODS: Sixty male BALB/c mice were randomly divided into four groups (n = 15 each): a normal group, a dextran sulfate sodium (DSS) group, a compound dracorhodin enema group, and a DSS + compound dracorhodin enema group. After inducing UC, the normal group and DSS group were given 1 mL saline, and the other two groups were given compound dracorhodin enema [0.075 g/(kg•d), 1 mL] by gavage. After treatment, disease activity index (DAI) score, colonic histopathology score (HI), lung HI score, and hematoxylin-eosin (HE) staining were used to evaluate the severity of inflammation. Enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, and real-time quantitative PCR (RT-QPCR) assay were used to detect the expression of interleukin (IL)-6 in the lung and colon.

RESULTS: Compared with the normal group and compound dracorhodin enema group, DAI score, colonic HI score, and lung HI score were significantly higher in the other two groups (P < 0.05). Compared with the DSS + compound dracorhodin enema group, colonic and pulmonary tissue inflammation was significantly more severe and pulmonary and colonic expression of IL-6 was significantly higher in the DSS group (P < 0.05).

CONCLUSION: Compound dracorhodin enema can decrease the expression of IL-6 and therefore alleviate UC and UC related lung injury in mice.

Targeting the raft-associated Akt signaling in hepatocellular carcinoma

Caveolin-1 and flotillin-1 are considered as markers of lipid rafts which can be regarded as sorting platforms for targeted transport of transmembrane proteins and are involved in fundamental cellular events such as signal transduction, cell adhesion, lipid/protein sorting, and human cancer. We addressed caveolin-1 and flotillin-1 expression in 90 human hepatocellular carcinoma (HCC) and adjacent noncancerous tissues (ANT) samples by SDS-PAGE and immunoblotting with specific antibodies. Significant caveolin-1 and flotillin-1 overexpression was found in HCC tissues compared to ANT and was confirmed by immunohistochemistry. Raft-associated Akt signaling pathway components involved in the regulation of cell survival were altered by western blotting in HCC microdomain-enriched subcellular fractions purified from paired HCC and ANT samples. Our results demonstrated that the activity of raft-associated but not total membrane Akt determines its cellular functions. Lipid rafts differ in different types of tissues, which allows for the possibility of tissue-type-specific targeting for cell survival.