Towards improved control of inflammatory bowel disease

ALDH1A Inhibition Suppresses Colitis and Alters α4β7 Integrin Expression on Activated T Cells in Mdr1a-/- Mice

There are limited pharmacological treatment options for inflammatory bowel disease (IBD), and some of these options are expensive and administered by injection or infusion. Thus, new cheaper and easier (oral) treatment options are needed. ALDH1A enzymes produce retinoic acid that can affect intestinal diseases such as IBD by regulating immune cells in the gut. We previously demonstrated that an orally deliverable ALDH1A inhibitor, WIN 18,466, can suppress colitis in an acute mouse model of IBD. Here, we tested the efficacy of ALDH1A inhibition in a chronic mouse model of IBD. Mdr1a-/- mice were treated with a diet containing WIN 18,446 starting 1 week prior to inducing colitis by H. bilis inoculation. Treatment was continued until the study end point and colitis was monitored based on clinical symptoms and confirmed by histological analysis. Immune cell phenotypes in colon-draining lymph nodes (cMLN) were analyzed. WIN 18,446 treatment reduced clinical symptoms and improved histopathologic colitis scores. This was associated with decreased expression of the gut homing integrin, α4β7, on T cells in cMLN; increased expression of CD103, a protein associated with tissue-resident memory T cells; and changes in dendritic cells, plasmacytoid dendritic cells and B cells in inhibitor-treated mice. ALDH1A inhibition broadly influences immune cells during colitis and is a potential new target for IBD treatment. Future studies will be needed to determine the efficacy of ALDH1A inhibition on active colitis and to evaluate its relative efficacy in comparison to approved drugs.

MiRNA-Based Therapies for the Treatment of Inflammatory Bowel Disease: What Are We Still Missing?

Micro-RNAs (miRNAs) are noncoding RNAs usually 24-30 nucleotides long that play a central role in epigenetic mechanisms of inflammatory diseases and cancers. Recently, several studies have assessed the involvement of miRNAs in the pathogenesis of inflammatory bowel disease (IBD) and colitis-associated neoplasia. Particularly, it has been shown that many members of miRNAs family are involved in the pathways of inflammation and fibrogenesis of IBD; therefore, their use as inflammatory and fibrosis biomarkers has been postulated. In light of these results, the role of miRNAs in IBD therapy has been proposed and is currently under investigation with many in vitro and in vivo studies, murine models, and a phase 2a trial. The accumulating data have pushed miRNA-based therapy closer to clinical practice, although many open questions remain. With this systematic review, we discuss the current knowledge about the therapeutic effects of miRNAs mimicking and inhibition, and we explore the new potential targets of miRNA family for the treatment of inflammation and fibrosis in IBD.

Psychological stress in inflammatory bowel disease: Psychoneuroimmunological insights into bidirectional gut–brain communications

Inflammatory bowel disease (IBD), mainly including ulcerative colitis (UC) and Crohn’s disease (CD), is an autoimmune gastrointestinal disease characterized by chronic inflammation and frequent recurrence. Accumulating evidence has confirmed that chronic psychological stress is considered to trigger IBD deterioration and relapse. Moreover, studies have demonstrated that patients with IBD have a higher risk of developing symptoms of anxiety and depression than healthy individuals. However, the underlying mechanism of the link between psychological stress and IBD remains poorly understood. This review used a psychoneuroimmunology perspective to assess possible neuro-visceral integration, immune modulation, and crucial intestinal microbiome changes in IBD. Furthermore, the bidirectionality of the brain–gut axis was emphasized in the context, indicating that IBD pathophysiology increases the inflammatory response in the central nervous system and further contributes to anxiety- and depression-like behavioral comorbidities. This information will help accurately characterize the link between psychological stress and IBD disease activity. Additionally, the clinical application of functional brain imaging, microbiota-targeted treatment, psychotherapy and antidepressants should be considered during the treatment and diagnosis of IBD with behavioral comorbidities. This review elucidates the significance of more high-quality research combined with large clinical sample sizes and multiple diagnostic methods and psychotherapy, which may help to achieve personalized therapeutic strategies for IBD patients based on stress relief.

Impact of Non-Pharmacological Interventions on the Mechanisms of Atherosclerosis

Atherosclerosis remains the leading cause of mortality and morbidity worldwide characterized by the deposition of lipids and fibrous elements in the form of atheroma plaques in vascular areas which are hemodynamically overloaded. The global burden of atherosclerotic cardiovascular disease is steadily increasing and is considered the largest known non-infectious pandemic. The management of atherosclerotic cardiovascular disease is increasing the cost of health care worldwide, which is a concern for researchers and physicians and has caused them to strive to find effective long-term strategies to improve the efficiency of treatments by managing conventional risk factors. Primary prevention of atherosclerotic cardiovascular disease is the preferred method to reduce cardiovascular risk. Fasting, a Mediterranean diet, and caloric restriction can be considered useful clinical tools. The protective impact of physical exercise over the cardiovascular system has been studied in recent years with the intention of explaining the mechanisms involved; the increase in heat shock proteins, antioxidant enzymes and regulators of cardiac myocyte proliferation concentration seem to be the molecular and biochemical shifts that are involved. Developing new therapeutic strategies such as vagus nerve stimulation, either to prevent or slow the disease’s onset and progression, will surely have a profound effect on the lives of millions of people.

Bidirectional communication between neural and immune systems

The immune and nervous systems share many features, including receptor and ligand expression, enabling efficient communication between the two. Accumulating evidence suggests that the communication is bidirectional, with the neural system regulating immune cell functions and vice versa. Steroid hormones from the hypothalamus-pituitary-adrenal gland axis are examples of systemic regulators for this communication. Neural reflexes describe regional regulation mechanisms that are a historically new concept that helps to explain how the neural and body systems including immune system communicate. Several recently identified neural reflexes, including the inflammatory reflex and gateway reflex, significantly impact the activation status of the immune system and are associated with inflammatory diseases and disorders. Either pro-inflammatory or anti-inflammatory effects can be elicited by these neural reflexes. On the other hand, the activities of immune cells during inflammation, for example the secretion of inflammatory mediators, can affect the functions of neuronal systems via neural reflexes and modulate biological outputs via specific neural pathways. In this review article, we discuss recent advances in the understanding of bidirectional neuro-immune interactions, with a particular focus on neural reflexes.

The brain-gut axis, inflammatory bowel disease and bioelectronic medicine

The hallmark of inflammatory bowel diseases (IBD) is chronic intestinal inflammation with typical onset in adolescents and young adults. An abundance of neutrophils is seen in the inflammatory lesions, but adaptive immunity is also an important player in the chronicity of the disease. There is an unmet need for new treatment options since modern medicines such as biological therapy with anti-cytokine antibodies still leave a substantial number of patients with persisting disease activity. The role of the central nervous system and its interaction with the gut in the pathophysiology of IBD have been brought to attention both in animal models and in humans after the discovery of the inflammatory reflex. The suggested control of gut immunity by the brain-gut axis represents a novel therapeutic target suitable for bioelectronic intervention. In this review, we discuss the role of the inflammatory reflex in gut inflammation and the recent advances in the treatment of IBD by intervening with the brain-gut axis through bioelectronic devices.

Natural-Derived Polysaccharides From Plants, Mushrooms, and Seaweeds for the Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease impairing the gastrointestinal tract, and its incidence and prevalence have been increasing over time worldwide. IBD greatly reduces peoples' quality of life and results in several life-threatening complications, including polyp, toxic colonic dilatation, intestinal perforation, gastrointestinal bleeding, and cancerization. The current therapies for IBD mainly include drugs for noncritical patients and operation for critical patients. However, continuous use of these drugs causes serious side effects and increased drug resistance, and the demand of effective and affordable drugs with minimal side effects for IBD sufferers is urgent. Natural-derived polysaccharides are becoming a research hotspot for their therapeutic effects on IBD. This study focuses on the research progress of various natural polysaccharides from plants, seaweeds, and mushrooms for the treatment of IBD during recent 20 years. Regulation of oxidative stress, inflammatory status, gut microbiota, and immune system and protection of the intestinal epithelial barrier function are the underlying mechanisms for the natural-derived polysaccharides to treat IBD. The excellent efficacy and safety of polysaccharides make them promising candidates for IBD therapy.

Pioglitazone Attenuates Experimental Colitis-Associated Hyperalgesia through Improving the Intestinal Barrier Dysfunction

Impaired intestinal mucosal integrity during colitis involves the peroxisome proliferator-activated receptor-γ (PPARγ), an important anti-inflammatory factor in intestinal mucosa homoeostasis, which is a potential target in colitis. Recurrent chronic pain is a vital pathogenetic feature of colitis. Nevertheless, potential functions of PPARγ in the colitis-associated hyperalgesia remain unclear. This study aimed to investigate biological roles of pioglitazone in relieving colitis-associated pain hypersensitivity by a PPARγ tight junction protein-dependent mechanism during the course of dextran sodium sulfate (DSS)-induced intestinal inflammation. The DSS-induced colitis model was generated in C57BL/6 mice. Changes in colitis induced the injury of intestinal mucosal barrier and hyperalgesia after a 6-day treatment of pioglitazone (25 mg/kg, IP injection) were assessed through immunofluorescent, hematoxylin and eosin (H&E) staining, western blot analysis, and determination of paw withdrawal mechanical threshold. A significant reduction of paw withdrawal mechanical threshold occurred after DSS treatment. Follow-up data showed that systematic administration of PPARγ agonist pioglitazone ameliorated the DSS-induced colitis and the development of colitis-associated hyperalgesia by repairing the intestinal mucosal barrier. The tight junction proteins ZO-1 and Claudin-5 were upregulated by PPARγ signaling, which in turn promoted the improvement of intestinal barrier function. Moreover, pioglitazone inhibited phosphorylation of ERK and NF-κB in the colon and decreased the levels of inflammatory cytokines in both colon spine tissues. Furthermore, systemically pioglitazone treatment inhibited the activation of microglia and astrocytes, as well as DSS-induced phosphorylation of NR2B subunit in spinal cord, which was correspondingly consistent with the pain behavior. Pioglitazone ameliorates DSS-induced colitis and attenuates colitis-associated mechanical hyperalgesia, with improving integrity of the intestinal mucosal barrier by directly upregulating tight junction proteins. The PPARγ-tight junction protein signaling might be a potential therapeutic target for the treatment of colitis-associated chronic pain.

Increased serum nesfatin-1 levels in patients with inflammatory bowel diseases

BACKGROUND

Adipokines are adipose tissue-derived secreted molecules that can exert anti-inflammatory or proinflammatory activities. Altered expression of adipokines has been described in various inflammatory diseases, including inflammatory bowel diseases (IBDs) such as Crohn's disease (CD) and ulcerative colitis (UC). Little is known about nesfatin-1, a recently identified adipokine, in IBD. The aim of this study was to investigate serum nesfatin-1 levels in patients with IBD.

METHODS

This study included a total of 52 adult individuals (17 patients with CD, 18 patients with UC and 17 healthy volunteers) with similar age and body mass index. Serum nesfatin-1 levels were measured by ELISA in healthy individuals and patients with IBD in their active and remission periods. Blood inflammation markers including C reactive protein (CRP), erythrocyte sedimentation (ESR) and white cell count (WCC) were also measured in patients.

RESULTS

We found significantly elevated levels of serum nesfatin-1 in the active disease period in both patients with CD (p=0.00003) and patients with UC (p=0.00001), compared with healthy individuals. Serum nesfatin-1 levels moderately decreased in the remission period; however, they were still significantly higher than that of healthy individuals. Receiver operating characteristic curve analyses indicated serum nesfatin-1 with an excellent diagnostic value for IBD. Finally, patients had significantly high CRP, ESR and WCC in the active IBD; however, we found the nesfatin-1 strongly correlated only with ESR in the active CD.

CONCLUSION

This is the first study investigating the circulating levels of nesfatin-1 in patients with IBD. Serum nesfatin-1 may serve as an additional inflammatory marker for diagnosis of IBD in affected individuals.

Protective Effects of ALDH1A Enzyme Inhibition on Helicobacter-Induced Colitis in Smad3-/- Mice are Associated with Altered α4ß7 Integrin Expression on Activated T Cells

Many inflammatory bowel disease (IBD) patients require surgical intervention due to limited pharmacological treatment options. Antibodies targeting α4ß7, a gut-homing integrin, are one of the most promising IBD treatments. As retinoic acid (RA) regulates expression of gut-homing proteins including α4ß7 integrin, we tested if ALDH1A enzymes in the RA synthesis pathway could be targeted for IBD treatment using a potent inhibitor, WIN 18,446. Age- and sex-matched Smad3^-/- mice were fed a diet with and without WIN 18,446 for 3 weeks before triggering inflammation with Helicobacter bilis infection. Colitis was evaluated by histopathology one week following the IBD trigger, and T cell subsets were evaluated before and after the IBD trigger. WIN 18,446 treatment significantly reduced IBD severity in Smad3^-/- mice and reduced expression of α4ß7 integrin on multiple activated CD4⁺ T cell subsets. This change was associated with increased ratios of induced regulatory T cells to Th17 cells during the inflammatory response in the draining lymph nodes. These studies indicate that RA reduction via ALDH1A enzyme inhibition is a potential new target for IBD treatment. Further studies are needed to examine its effects on other types of immune cells, to evaluate the efficacy window for this target, and to determine its efficacy in other animal models of IBD.

Sishen Pill Treatment of DSS-Induced Colitis via Regulating Interaction With Inflammatory Dendritic Cells and Gut Microbiota

Sishen Pill (SSP) is a typical prescription in the pharmacopeia of traditional Chinese medicine (TCM), and is usually used to treat inflammatory bowel disease (IBD). It is known that inflammatory dendritic cells (DCs) and imbalance of gut microbiota play significant roles in the pathogenesis of IBD. However, it is not clear whether SSP can treat IBD by regulating interaction of DCs and gut microbiota. In the present study, the levels of inflammatory DCs and gut microbiota were analyzed by flow cytometry and 16S rDNA analysis. SSP relieved the pathological damage to the colon of mice with colitis induced by dextran sodium sulfate (DSS). As typical indicators of inflammatory DCs, the levels of CD11c⁺CD103⁺E-cadherin⁺ cells and pro-inflammatory cytokines [interleukin (IL)-1β, -4, -9, and -17A] were decreased in mice with colitis treated by SSP for 10 days. Simultaneously, the gut microbiota composition was regulated, and beneficial bacteria were increased and pathogenic bacteria were reduced. The results indicated that SSP regulated the interaction between inflammatory DCs and gut microbiota to treat DSS-induced colitis.

Vagotomy and subsequent risk of inflammatory bowel disease: a nationwide register-based matched cohort study

BACKGROUND

The vagus nerve provides essential parasympathetic innervation to the gastrointestinal system and is known to have anti-inflammatory properties.

AIMS

To explore the relationship between vagotomy and the risk of inflammatory bowel disease (IBD) and its major categories: Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

A matched cohort comprising 15 637 patients undergoing vagotomy was identified through the Swedish Patient Register from 1964 to 2010. Each vagotomised patient was matched for birth year and gender with 40 nonvagotomised individuals on the date of vagotomy. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for IBD using flexible parametric models adjusted for matching variables, year of vagotomy, birth country, chronic obstructive pulmonary disease and comorbidity index.

RESULTS

We observed 119 (0.8%) patients with vagotomy developed IBD compared to 3377 (0.5%) IBD cases in nonvagotomised individuals. The crude incidence of IBD (per 1000 person-years) was 0.38 for vagotomised patients and 0.25 for nonvagotomised individuals. We observed a time-dependent elevated risk of IBD associated with vagotomy, for instance, the HR (95% CI) was 1.80 (1.40-2.31) at year 5 and 1.49 (1.14-1.96) at year 10 post-vagotomy. The association appeared to be stronger for truncal than selective vagotomy and limited to CD (HR was 3.63 [1.94-6.80] for truncal and 2.06 [1.49-2.84] for selective vagotomy) but not UC (1.36 [0.71-2.62] for truncal and 1.25 [0.95-1.63] for selective vagotomy).

CONCLUSIONS

We found a positive association between vagotomy and later IBD, particularly for CD. The finding indirectly underlines the beneficial role of the vagal tone in IBD.

Neural reflex control of vascular inflammation

Atherosclerosis is a multifactorial chronic inflammatory disease that underlies myocardial infarction and stroke. Efficacious treatment for hyperlipidemia and hypertension has significantly reduced morbidity and mortality in cardiovascular disease. However, atherosclerosis still confers a considerable risk of adverse cardiovascular events. In the current mechanistic understanding of the pathogenesis of atherosclerosis, inflammation is pivotal both in disease development and progression. Recent clinical data provided support for this notion and treatment targeting inflammation is currently being explored. Interestingly, neural reflexes regulate cytokine production and inflammation. Hence, new technology utilizing implantable devices to deliver electrical impulses to activate neural circuits are currently being investigated in treatment of inflammation. Hopefully, it may become possible to target vascular inflammation in cardiovascular disease using bioelectronic medicine. In this review, we discuss neural control of inflammation and the potential implications of new therapeutic strategies to treat cardiovascular disease.

A core-shell structure QRu-PLGA-RES-DS NP nanocomposite with photothermal response-induced M2 macrophage polarization for rheumatoid arthritis therapy

Rheumatoid arthritis (RA) is a degenerative joint disease caused by autoimmunity; for the effective treatment of RA while avoiding the side effects of conventional drugs, we have proposed a new therapeutic strategy to eliminate the inflammatory response in RA by regulating the immune system that promotes the transformation of M1-type macrophages to M2-type macrophages. Herein, we designed and synthesized a core-shell nanocomposite (QRu-PLGA-RES-DS NPs), which showed an effective therapeutic effect on RA by accurately inducing the polarization of M2 macrophages. In this system, the quadrilateral ruthenium nanoparticles (QRuNPs) with a photothermal effect were utilized as a core and the thermosensitive molecular poly (lactic-co-glycolic acid) (PLGA) modified with the targeted molecule dextran sulfate (DS) was employed as a shell. Then, the nanocarrier QRu-PLGA-DS NPs effectively improved the water solubility and targeting of resveratrol (RES) through self-assembly. Therefore, the QRu-PLGA-RES-DS NPs significantly enhanced the ability of RES to reverse the M1 type macrophages to the M2 type macrophages through an accurate release. In vivo experiments further demonstrated that the QRu-PLGA-RES-DS NPs could effectively accumulate in the lesion area with an exogenous stimulus, and this significantly enhanced the transformation of the M2 type macrophages and decreased the recruitment of the M1 type macrophages. Furthermore, the QRu-PLGA-RES-DS NPs effectively treated RA by eliminating the inflammatory response; in addition, photoacoustic imaging (PA) of the QRu NPs provided image guidance for the distribution and analysis of nanomedicine in inflammatory tissues. Hence, this therapeutic strategy promotes the biological applications of Ru-based nanoparticles in disease treatment.

Mechanisms of action of molecules with anti-TNF-alpha activity on intestinal barrier inflammation: A systematic review protocol

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha), among cytokines that mediate the inflammatory process, plays an important role in diseases involving the loss of intestinal barrier integrity. Several molecules with anti-TNF-alpha activity have been studied aiming to develop new therapies. The purpose of this paper is to describe the systematic review protocol of experimental studies that determine mechanisms of action of molecules with anti-TNF-alpha activity on intestinal barrier inflammation.

METHODS

This protocol is guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes Protocols (PRISMA-P). The databases to be searched are PubMed, EMBASE, Scopus, ScienceDirect, and Web of Science. Experimental studies in rats or mice that assessed the activity of anti-TNF-alpha molecules in models of intestinal barrier inflammation will be included in the systematic review. Studies characteristics, experimental model, and main results will be described and the bias risk assessment will be performed. Two independent reviewers will perform study selection, data extraction, and methodological quality assessment. A narrative synthesis will be made for the included studies. Also, if sufficient data is available, a meta-analysis will be conducted. I statistics will be used to assess heterogeneity.

RESULTS

The present protocol will assist in producing a systematic review that identifies the mechanisms underlying the reduction of TNF-alpha in intestinal barrier inflammation models.

CONCLUSION

The systematic review may contribute to the theoretical basis of research on new molecules with anti-TNF-alpha potential and, consequently, in the development of new therapies employed in humans.

PROSPERO REGISTRATION NUMBER

CRD42019131862.

An Effective Method for Acute Vagus Nerve Stimulation in Experimental Inflammation

Neural reflexes regulate inflammation and electrical activation of the vagus nerve reduces inflammation in models of inflammatory disease. These discoveries have generated an increasing interest in targeted neurostimulation as treatment for chronic inflammatory diseases. Data from the first clinical trials that use vagus nerve stimulation (VNS) in treatment of rheumatoid arthritis and Crohn’s disease suggest that there is a therapeutic potential of electrical VNS in diseases characterized by excessive inflammation. Accordingly, there is an interest to further explore the molecular mechanisms and therapeutic potential of electrical VNS in a range of experimental settings and available genetic mouse models of disease. Here, we describe a method for electrical VNS in experimental inflammation in mice.