Interferon-gamma depresses human intestinal smooth muscle cell contractility: Relevance to inflammatory gut motility disturbances

A type 1 immune-stromal cell network mediates disease tolerance against intestinal infection

Type 1 immunity mediates host defense through pathogen elimination, but whether this pathway also impacts tissue function is unknown. Here, we demonstrate that rapid induction of interferon γ (IFNγ) signaling coordinates a multicellular response that is critical to limit tissue damage and maintain gut motility following infection of mice with a tissue-invasive helminth. IFNγ production is initiated by antigen-independent activation of lamina propria CD8+ T cells following MyD88-dependent recognition of the microbiota during helminth-induced barrier invasion. IFNγ acted directly on intestinal stromal cells to recruit neutrophils that limited parasite-induced tissue injury. IFNγ sensing also limited the expansion of smooth muscle actin-expressing cells to prevent pathological gut dysmotility. Importantly, this tissue-protective response did not impact parasite burden, indicating that IFNγ supports a disease tolerance defense strategy. Our results have important implications for managing the pathophysiological sequelae of post-infectious gut dysfunction and chronic inflammatory diseases associated with stromal remodeling.

A Potential Use of Vidarabine: Alleviation of Functional Constipation Through Modulation of the Adenosine A2A Receptor-MLC Signaling Pathway and the Gut Microbiota

Vidarabine (VID) is an antiviral medication that is commonly utilized to treat conditions such as hand, foot, and mouth disease and herpes. Constipation is a prevalent complication of these diseases. Could VID treat these diseases by influencing defecation behavior? To date, no studies have been conducted on the potential of VID to relieve constipation. Therefore, a systematic investigation was conducted into the laxative effects and mechanisms of VID using loperamide-induced functional constipated mice. The findings indicate that the oral administration of VID promoted gastrointestinal peristalsis, improved fecal properties, facilitated defecation, and demonstrated a significant laxative effect on functional constipated mice. It has been demonstrated that VID may increase the water content of feces by regulating the expression of aquaporins (AQP3, AQP4, and AQP8) in the colon and promote intestinal motility by regulating the expression of neurotransmitters (AChE and VIP) and the adenosine A2A receptor-myosin light chain (A2AR-MLC) signaling pathway in constipated mice. Concurrently, VID may also reduce colonic inflammation in constipated mice, reinforce the gut barrier function, and alter the composition and structure of the gut microbial community. Some microbial taxa, including Firmicutes and Lactobacillus, were found to be associated with the alleviation of constipation, while other taxa, including Bacteroidetes, Proteobacteria, Muribaculaceae, Muribaculum, norank__f__Desulfovibrionaceae, and Parasutterella, were found to be associated with constipation. These results indicate that the gut microbiota may play a significant role in the alleviation of constipation by VID. These findings confirm the efficacy of VID in a constipated animal model, which justifies further investigation into its potential clinical applications.

Rosmarinic acid alleviates intestinal inflammatory damage and inhibits endoplasmic reticulum stress and smooth muscle contraction abnormalities in intestinal tissues by regulating gut microbiota

The host-bacterial interactions play the key role in inflammatory bowel disease (IBD). Dysbiosis of the intestinal flora can lead to pathological changes in the intestine. Rosmarinic acid (RA) is a natural phenolic acid compound with antioxidant, anti-cancer, anti-inflammatory, anti-apoptotic, anti-fibrotic, and anti-bacterial activities that has a palliative effect on acute IBD. We have established an in vivo model for mice. Histological staining was performed to directly observe RA alterations in the intestinal tract. The alteration of RA on mouse intestinal flora was observed by 16S rRNA high-throughput sequencing, and the effect of RA on intestinal mechanism of action was detected by qPCR and western blot. The results showed that RA had a significant protective effect on the intestine. RA upregulated the abundance of Lactobacillus johnsonii and Candidatus Arthromitus sp SFB-mouse-NL and downregulated the abundance of Bifidobacterium pseudolongum, Escherichia coli, and Romboutsia ilealis. RA downregulated the expressions of ROCK, RhoA, CaM, MLC, MLCK, ZEB1, ZO-1, ZO-2, occludin, E-cadherin, IL-1β, IL-6, TNF-α, GRP78, PERK, IRE1, ATF6, CHOP, Caspase12, Caspase9, Caspase3, Bax, Cytc, RIPK1, RIPK3, MLKL, and upregulated the expression of IL-10 and Bcl-2. These results displayed that RA inhibited the inflammation, which is caused by tight junction damage, by repairing intestinal flora dysbiosis, relieved endoplasmic reticulum stress, inhibited cell death, and corrected smooth muscle contractile dysregulation. The results of this study revealed RA could have a protective effect on the small intestine of mice by regulating intestinal flora. IMPORTANCE Inflammatory bowel disease (IBD) is a chronic, relapsing, remitting disorder of the gastrointestinal system. In this study, we investigated the protective effects of rosmarinic acid on the intestinal tract. The results showed that RA was effective in reducing inflammatory damage, endoplasmic reticulum stress, smooth muscle contraction abnormalities, and regulating intestinal flora disorders.

Methamphetamine and Designer Stimulants Modulate Tonic Human Cerebrovascular Smooth Muscle Contractility: Relevance to Drug-Induced Neurovascular Stress

To avoid criminal prosecution, clandestine chemists produce designer stimulants that mimic the pharmacological and psychoactive effects of conventional stimulants, such as methamphetamine. Following persistent or high-dose exposure, both acute vasoconstriction and loss of vascular homeostasis are reported dangers of conventional stimulants, and designer stimulants may pose even greater dangers. To compare the effects of a conventional stimulant and two designer stimulants on vascular contraction, this study examined the direct effects of 1,3-benzodioxolylbutanamine (BDB) and N-butylpentylone in comparison to methamphetamine on the function of human brain vascular smooth muscle cells (HBVSMCs). HBVSMCs suspended in collagen gels were exposed to varying concentrations of each drug, and the degree of constriction was assessed over one week. The MTT assay was used to measure the impact of the three drugs on the cellular metabolic activity as a marker of cellular toxicity. The highest concentration tested of either methamphetamine or N-butylpentylone produced a loss of HBVSMC contractility and impaired cellular metabolism. BDB showed a similar pattern of effects, but, uniquely, it also induced vasoconstrictive effects at substantially lower concentrations. Each drug produced direct effects on HBVSMC contraction that may be a mechanism by which the cardiovascular system is damaged following high-dose or persistent exposure, and this could be exacerbated by any sympathomimetic effects of these compounds in whole organisms. BDB appears to impact HBVSMC function in ways distinct from methamphetamine and N-butylpentylone, which may present unique dangers.

Development of Adaptive Immunity and Its Role in Lung Remodeling

Asthma is characterized by airflow limitations resulting from bronchial closure, which can be either reversible or fixed due to changes in airway tissue composition and structure, also known as remodeling. Airway remodeling is defined as increased presence of mucins-producing epithelial cells, increased thickness of airway smooth muscle cells, angiogenesis, increased number and activation state of fibroblasts, and extracellular matrix (ECM) deposition. Airway inflammation is believed to be the main cause of the development of airway remodeling in asthma. In this chapter, we will review the development of the adaptive immune response and the impact of its mediators and cells on the elements defining airway remodeling in asthma.

The Role of Inflammatory Mediators in the Development of Gastrointestinal Motility Disorders

Feeding intolerance and the development of ileus is a common complication affecting critically ill, surgical, and trauma patients, resulting in prolonged intensive care unit and hospital stays, increased infectious complications, a higher rate of hospital readmission, and higher medical care costs. Medical treatment for ileus is ineffective and many of the available prokinetic drugs have serious side effects that limit their use. Despite the large number of patients affected and the consequences of ileus, little progress has been made in identifying new drug targets for the treatment of ileus. Inflammatory mediators play a critical role in the development of ileus, but surprisingly little is known about the direct effects of inflammatory mediators on cells of the gastrointestinal tract, and many of the studies are conflicting. Understanding the effects of inflammatory cytokines/chemokines on the development of ileus will facilitate the early identification of patients who will develop ileus and the identification of new drug targets to treat ileus. Thus, herein, we review the published literature concerning the effects of inflammatory mediators on gastrointestinal motility.

IFNγ-Treated Macrophages Induce EMT through the WNT Pathway: Relevance in Crohn’s Disease

Background: Fibrosis is a common complication of Crohn’s disease (CD) in which macrophages play a central role. Epithelial-mesenchymal transition (EMT) and the WNT pathway have been associated with fibrosis. We aim to analyse the relevance of the tissue microenvironment in macrophage phenotype and the EMT process. Methods: Intestinal surgical resections are obtained from control and CD patients with stenotic or penetrating behaviour. Cytokine’s expression, macrophage phenotype, EMT markers and WNT signalling pathway are determined by WB, RT-PCR, ELISA or Cytometry. U937 cells are treated with IFNγ, TNFα, IL1β, IL4 or IL10 and co-cultured with HT29 cells and, in some cases, are treated with XAV939 or miFZD4. The expression of macrophage, EMT and WNT pathway markers in U937 or HT29 cells is analysed by WB or RT-PCR. Results: IFNγ, WNT6, CD16 and CD86 are increased in the intestinal tissue of CD patients. IFNγ-treated U937 activated the EMT process and WNT pathway in HT29 cells, and the EMT process is mediated by FZD4. Conclusions: An IFNγ-rich microenvironment polarises macrophages, which induces EMT through the WNT pathway.

Tissue engineering of the gastrointestinal tract: the historic path to translation

The gastrointestinal (GI) tract is imperative for multiple functions including digestion, nutrient absorption, and timely waste disposal. The central feature of the gut is peristalsis, intestinal motility, which facilitates all of its functions. Disruptions in GI motility lead to sub-optimal GI function, resulting in a lower quality of life in many functional GI disorders. Over the last two decades, tissue engineering research directed towards the intestine has progressed rapidly due to advances in cell and stem-cell biology, integrative physiology, bioengineering and biomaterials. Newer biomedical tools (including optical tools, machine learning, and nuanced regenerative engineering approaches) have expanded our understanding of the complex cellular communication within the GI tract that lead to its orchestrated physiological function. Bioengineering therefore can be utilized towards several translational aspects: (i) regenerative medicine to remedy/restore GI physiological function; (ii) in vitro model building to mimic the complex physiology for drug and pharmacology testing; (iii) tool development to continue to unravel multi-cell communication networks to integrate cell and organ-level physiology. Despite the significant strides made historically in GI tissue engineering, fundamental challenges remain including the quest for identifying autologous human cell sources, enhanced scaffolding biomaterials to increase biocompatibility while matching viscoelastic properties of the underlying tissue, and overall biomanufacturing. This review provides historic perspectives for how bioengineering has advanced over time, highlights newer advances in bioengineering strategies, and provides a realistic perspective on the path to translation.

Deoxynivalenol interferes with intestinal motility via injuring the contractility of enteric smooth muscle cells: A novel hazard to the gastrointestinal tract by environmental toxins

Deoxynivalenol (DON) is a prevalent Fusarium mycotoxin, occurs predominantly in the global environment, especially in cereals, animal feed and food commodities. The widespread contamination causes a serious risk to human and animal health. DON usually impairs weight gain, which is presumably from its capacity to reduce feed intake by interfering with intestinal motility. To clarify the role of smooth muscle cells (SMCs) contractility in intestinal motility and growth inhibition caused by DON, twelve weaned piglets were firstly divided into two groups to feed control or Fusarium mycotoxin-contaminated (MC) diet. Results showed that the final body weight, average daily gain and average daily feed intake were significantly reduced in piglets fed the MC diet. Exposure to the MC diet also significantly decreased the thickness of smooth muscle layer and SMCs contractile markers expression (myosin heavy chain 11, smooth muscle actin gamma 2, transgelin, calponin 1) in jejunum and ileum of piglets. Furthermore, oral DON supplementation (3 mg/kg body weight) to mice in six consecutive days could significantly inhibit the upper intestinal transit, impede normal defecation and downregulate SMCs contractile markers expression in small intestine. Finally, we generated a porcine enteric smooth muscle cell line (PISMC), and found that DON could depress its contractility by decreasing PISMC proliferation, migration and contractile markers expression. In conclusion, these findings in vivo and in vitro suggest that DON, as a common environmental toxin, can not only reduce proliferative and motile phenotype, but also decrease contractile apparatus components (contractile markers expression) in SMCs, which in turn influences SMCs contractility and then interferes with intestinal motility and growth performance.

Effects of electroacupuncture on the intestinal motility and local inflammation are modulated by acupoint selection and stimulation frequency in postoperative ileus mice

BACKGROUND

Electroacupuncture (EA) is widely used in various gastrointestinal diseases around the world, including POI. Here, we investigated different therapeutic effects of EA using lower limb and abdomen acupoints.

METHODS

Intestinal manipulation was performed in 88 mice, and eight mice underwent a sham operation. Forty mice were randomly divided into model group and four EA groups receiving stimulation at ST36 (2, 10, 30, 100 Hz). The most effective frequency was then used in the following experiments. Forty-eight mice were randomly divided into six groups receiving EA treatment at ST37, ST39, ST25, CV4, CV12, and a non-acupuncture point. Gastrointestinal motility and plasma TNF-α, IL-6 were evaluated in all mice. The local immune response and α-smooth muscle actin (α-SMA) expression were assessed by immunofluorescence, ELISA, and HE staining.

RESULTS

ST36 stimulated with 10 or 30 Hz EA significantly increased the gastrointestinal motility and attenuated peripheral inflammation; however, ST36 stimulated with 2 or 100 Hz did not induce any effect. The therapeutic effects on motility and inflammation of 10 Hz EA in the ST36 group were similar in the ST36, ST37, ST39, or CV4 groups, but when applied to ST25, CV12 or non-acupoint had no significant differences. EA at ST36, ST37, ST39, or CV4 significantly inhibited local MPO activity, immune cells infiltration, and increased α-SMA.

CONCLUSIONS

EA at lower limb and abdomen acupoints with the same stimulation parameters had different therapeutic effects on postoperative dysmotility and inflammation. Furthermore, EA protected SMC to improve gastrointestinal transit by reducing local inflammation in the intestinal musculature in POI.

Nutritional support in sepsis: when less may be more

Despite sound basis to suspect that aggressive and early administration of nutritional support may hold therapeutic benefits during sepsis, recommendations for nutritional support have been somewhat underwhelming. Current guidelines (ESPEN and ASPEN) recognise a lack of clear evidence demonstrating the beneficial effect of nutritional support during sepsis, raising the question: why, given the perceived low efficacy of nutritionals support, are there no high-quality clinical trials on the efficacy of permissive underfeeding in sepsis? Here, we review clinically relevant beneficial effects of permissive underfeeding, motivating the urgent need to investigate the clinical benefits of delaying nutritional support during sepsis.