Disturbed in vitro adrenergic modulation of cytokine production in inflammatory bowel diseases in remission

Exploring the Impact of Cyanidin-3-Glucoside on Inflammatory Bowel Diseases: Investigating New Mechanisms for Emerging Interventions

Cyanidin-3-O-glucoside (C3G), the most widely distributed anthocyanin (ACN) in edible fruits, has been proposed for several bioactivities, including anti-inflammatory, neuro-protective, antimicrobial, anti-viral, anti-thrombotic and epigenetic actions. However, habitual intake of ACNs and C3G may vary widely among populations, regions, and seasons, among individuals with different education and financial status. The main point of C3G absorption occurs in the small and large bowel. Therefore, it has been supposed that the treating properties of C3G might affect inflammatory bowel diseases (IBD), such as ulcerative colitis (UC) and Crohn's disease (CD). IBDs develop through complex inflammatory pathways and sometimes may be resistant to conventional treatment strategies. C3G presents antioxidative, anti-inflammatory, cytoprotective, and antimicrobial effects useful for IBD management. In particular, different studies have demonstrated that C3G inhibits NF-κB pathway activation. In addition, C3G activates the Nrf2 pathway. On the other hand, it modulates the expression of antioxidant enzymes and cytoprotective proteins, such as NAD(P)H, superoxide dismutase, heme-oxygenase (HO-1), thioredoxin, quinone reductase-oxide 1 (NQO1), catalase, glutathione S-transferase and glutathione peroxidase. Interferon I and II pathways are downregulated by C3G inhibiting interferon-mediating inflammatory cascades. Moreover, C3G reduces reactive species and pro-inflammatory cytokines, such as C reactive protein, interferon-γ, tumor necrosis factor-α, interleukin (IL)-5, IL-9, IL-10, IL-12p70, and IL-17A in UC and CD patients. Finally, C3G modulates gut microbiota by inducing an increase in beneficial gut bacteria and increasing microbial abundances, thus mitigating dysbiosis. Thus, C3G presents activities that may have potential therapeutic and protective actions against IBD. Still, in the future, clinical trials should be designed to investigate the bioavailability of C3G in IBD patients and the proper therapeutic doses through different sources, aiming to the standardization of the exact clinical outcome and efficacy of C3G.

Stress and the brain-gut axis in functional and chronic-inflammatory gastrointestinal diseases: A transdisciplinary challenge

The broad role of stress in the brain-gut axis is widely acknowledged, with implications for multiple prevalent health conditions that are characterized by chronic gastrointestinal symptoms. These include the functional gastrointestinal disorders (FGID), such as irritable bowel syndrome and functional dyspepsia, as well as inflammatory bowel diseases (IBD) like ulcerative colitis and Crohn's disease. Although the afferent and efferent pathways linking the gut and the brain are modulated by stress, the fields of neurogastroenterology and psychoneuroendocrinology (PNE)/ psychoneuroimmunology (PNI) remain only loosely connected. We aim to contribute to bringing these fields closer together by drawing attention to a fascinating, evolving research area, targeting an audience with a strong interest in the role of stress in health and disease. To this end, this review introduces the concept of the brain-gut axis and its major pathways, and provides a brief introduction to epidemiological and clinical aspects of FGIDs and IBD. From an interdisciplinary PNE/PNI perspective, we then detail current knowledge regarding the role of chronic and acute stress in the pathophysiology of FGID and IBD. We provide an overview of evidence regarding non-pharmacological treatment approaches that target central or peripheral stress mechanisms, and conclude with future directions, particularly those arising from recent advances in the neurosciences and discoveries surrounding the gut microbiota.

Stress burden and neuroendocrine regulation of cytokine production in patients with ulcerative colitis in remission

Stress demonstrably contributes to disease course in patients with inflammatory bowel diseases but the underlying mechanisms remain elusive. Here, we investigated if neuroendocrine regulation of pro- and anti-inflammatory cytokine production by peripheral blood immune cells is altered in patients with ulcerative colitis in remission (UCR). Using a whole blood stimulation assay, we measured the sensitivity of lipopolysaccharide (LPS)-induced TNF-α and IL-10 production to the glucocorticoid receptor agonist dexamethasone (DEX), the β₂-adrenergic receptor agonist terbutaline (TERB), and the α7-nicotinic acetylcholine receptor agonist 3-[2,4-dimethoxy-benzylidene]-anabaseine (GTS-21) in UCR patients (N = 26) and in healthy controls (HC, N = 25). Additionally, we assessed anxiety and depression symptoms as well as chronic perceived stress and disease-specific quality of life. Results showed that UCR patients exhibited greater anxiety, depression and chronic stress levels than HC, and reduced disease-specific quality of life. Plasma concentrations of TNF-α, IL-8, C-reactive protein (CRP) and lipopolysaccharide binding protein (LBP) were significantly higher, while LPS-induced IL-10 production was substantially lower in UCR compared to HC. Independent of group, DEX and GTS-21 dose-dependently inhibited TNF-α and IL-10 production, whereas TERB inhibited TNF-α and upregulated IL-10 production. However, at higher TERB doses (i.e., stress levels), upregulation of IL-10 production was significantly diminished in UCR compared to HC. Together, these findings demonstrate that downregulation of pro-inflammatory cytokine production in peripheral blood immune cells through glucocorticoid, adrenergic, and cholinergic mechanisms is essentially normal in UC in clinical remission and as efficient as in healthy individuals. However, UCR patients exhibited signs of systemic low-grade inflammation and dysregulation of anti-inflammatory IL-10 production. Impaired adrenergic upregulation of IL-10 production during remission could be one mechanism how stress facilitates relapse and conversion to symptomatic disease in these patients.

Dextran sulfate sodium-induced acute experimental colitis in C57BL/6 mice is mitigated by selenium

BACKGROUND

Sodium selenite has been shown to have a protective role in experimental colitis. Th1 and Th17 responses are involved in the pathogenesis of dextran sulfate sodium (DSS)-induced colitis and inflammatory bowel disease. This study investigated whether sodium selenite can suppress Th1/Th17-mediated experimental colitis.

METHODS

Mice were administered sodium selenite (2μg/g body weight) by gavage daily for 30days. Beginning on day 21, mice were administered 2.5% oral DSS for 9days. The mice were sacrificed on day 31. Survival rates, clinical symptoms, colon lengths, and histological changes were determined.

RESULTS

Pretreatment with sodium selenite (2μg/g body weight) improved survival rates, colon shortening, body weight loss, disease activity index, and histopathological score in mice with DSS-induced colitis. Pretreatment with sodium selenite restored interleukin-10 and Foxp3 excretion, as well as reducing the levels of interferon-γ and interleukin-17A.

CONCLUSIONS

Pretreatment with sodium selenite showed therapeutic potential for preventing colitis in mice. This effect may be mediated by the immunomodulation of regulatory T cells, expressing anti-inflammatory genes that suppress Th1 and Th17 responses.

A mechanistic review on plant-derived natural compounds as dietary supplements for prevention of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a recurrent idiopathic inflammatory condition, characterized by disruption of the gut mucosal barrier. This mechanistic review aims to highlight the significance of plant-derived natural compounds as dietary supplements, which can be used in addition to restricted conventional options for the prevention of IBD and induction of remission. Various clinical trials confirmed the effectiveness and tolerability of natural supplements in patients with IBD. Mounting evidence suggests that these natural compounds perform their protective and therapeutic effect on IBD through numerous molecular mechanisms, including anti-inflammatory and immunoregulatory, anti-oxidative stress, modulation of intracellular signaling transduction pathways, as well as improving gut microbiota. In conclusion, natural products can be considered as dietary supplements with therapeutic potential for IBD, provided that their safety and efficacy is confirmed in future well-designed clinical trials with adequate sample size.

Dietary anthocyanins as a complementary medicinal approach for management of inflammatory bowel disease

Inflammatory bowel disease (IBD) is thought to result from a chronic or relapsing activation of the immune system in the GI tract. A growing body of evidence confirms the health benefits of dietary anthocyanins as plant-derived natural agents. The aim of this review is to provide an overview of several natural products rich in anthocyanins used worldwide for the treatment of IBD. Anthocyanins possess both protective and therapeutic functions in the management of IBD by alleviating oxidative stress processes, cytoprotective functions, downregulation of inflammatory cytokines and suppressing cellular signaling pathways of inflammatory processes. In conclusion, the consumption of anthocyanin-rich natural formulations must be promoted on the basis of their possible function in the prevention and treatment of gastrointestinal inflammatory disorders.

Acute psychosocial stress induces differential short-term changes in catecholamine sensitivity of stimulated inflammatory cytokine production

BACKGROUND

We have previously shown that psychosocial stress induces acute changes in glucocorticoid (GC) sensitivity of pro-inflammatory cytokine production. However, hormones of the sympathetic adrenal medullary system complement endocrine regulation of inflammatory responses. The current study therefore aimed at investigating the effects of repeated acute stress exposure on catecholamine sensitivity of inflammatory cytokine production.

METHODS

Twenty healthy male participants were subjected to the Trier Social Stress Test on two consecutive days. Blood samples were taken before and repeatedly after stress. Whole blood was stimulated with lipopolysaccharide and incubated with increasing concentrations of epinephrine (E) and norepinephrine (NE) for 18h. Tumor-necrosis-factor (TNF) alpha and interleukin (IL)-6 were measured in culture supernatants.

RESULTS

Overall, incubation with E and NE induced dose-dependent suppression of TNF-alpha (NE: F=77.66, p<.001; E: F=63.38, p<.001), and IL-6 production (NE: F=28.79, p<.001; E: F=24.66, p<.001). Acute stress exposure resulted in reduced sensitivity of TNF-alpha (NE: F=6.36, p<.001; E: F=4.86, p=.005), but not IL-6 (NE: F=1.07, p=.38; E: F=0.88, p=.50) to the inhibitory signals of E and NE. No evidence of habituation of these effects was found (all p⩾.22).

CONCLUSIONS

The present findings extend our knowledge on changes in inflammatory target tissue sensitivity in response to acute psychosocial stress from glucocorticoid-dependent effects to catecholamine-dependent effects. Stress-induced decreases in catecholamine sensitivity thereby suggest intracellular processes aiding in maintaining a healthy endocrine-immune interplay. Longitudinal studies will have to investigate the processes leading from a supposedly beneficial short-term catecholamine resistance in response to acute stress to basal catecholamine resistance observed in relation to negative health outcomes.

Preventive effects of cranberry products on experimental colitis induced by dextran sulphate sodium in mice

With the prevalence of inflammatory bowel disease (IBD) and its associated risk for development of colorectal cancer, it is of great importance to prevent and treat IBD. However, due to the complexity of etiology and potentially serious adverse effects, treatment options for IBD are relatively limited. Thus, the purpose of this study was to identify a safe food-based approach for the prevention and treatment of IBD. In this study, we tested the effects of cranberry products on preventing dextran sulphate sodium-induced murine colitis. Our results suggest that both cranberry extract and dried cranberries-fed groups had a significantly reduced disease activity index, where dried cranberries were more effective in preventing colitis than cranberry extract. Shortening of colon length, colonic myeloperoxidase activity and production of pro-inflammatory cytokines were attenuated in animals fed dried cranberries compared to the controls. The current report suggests that cranberries can be applied to prevent and reduce the symptoms of IBD.

Variability in stress system regulatory control of inflammation: a critical factor mediating health effects of stress

Chronic stress has been associated with disease but the biological pathways are not completely understood. Stress systems such as the hypothalamus-pituitary-adrenal axis and the autonomic nervous system are prime candidates but alterations in their baseline activity are not consistently found in chronic stress. Evidence suggests that stress-related changes in the sensitivity of inflammatory pathways towards glucocorticoid regulation, that is, the development of glucocorticoid resistance, might help explain inflammatory disinhibition and the subsequent development of disease. Recent data show a similarly important role for sympathetic and parasympathetic modulation of the inflammatory cascade for the maintenance of health. This article argues that variation of target tissue sensitivity towards anti-inflammatory effects of the hypothalamus-pituitary-adrenal axis, as well as sympathetic and parasympathetic signaling, might be involved in the development of low-grade inflammation under chronic psychosocial stress.

Abdominal pain in Irritable Bowel Syndrome: a review of putative psychological, neural and neuro-immune mechanisms

Chronic abdominal pain is a common symptom of great clinical significance in several areas of medicine. In many cases no organic cause can be established resulting in the classification as functional gastrointestinal disorder. Irritable Bowel Syndrome (IBS) is the most common of these conditions and is considered an important public health problem because it can be disabling and constitutes a major social and economic burden given the lack of effective treatments. IBS aetiology is most likely multi-factorial involving biological, psychological and social factors. Visceral hyperalgesia (or hypersensitivity) and visceral hypervigilance, which could be mediated by peripheral, spinal, and/or central pathways, constitute key concepts in current research on pathophysiological mechanisms of visceral hyperalgesia. The role of central nervous system mechanisms along the "brain-gut axis" is increasingly appreciated, owing to accumulating evidence from brain imaging studies that neural processing of visceral stimuli is altered in IBS together with long-standing knowledge regarding the contribution of stress and negative emotions to symptom frequency and severity. At the same time, there is also growing evidence suggesting that peripheral immune mechanisms and disturbed neuro-immune communication could play a role in the pathophysiology of visceral hyperalgesia. This review presents recent advances in research on the pathophysiology of visceral hyperalgesia in IBS, with a focus on the role of stress and anxiety in central and peripheral response to visceral pain stimuli. Together, these findings support that in addition to lower pain thresholds displayed by a significant proportion of patients, the evaluation of pain appears to be altered in IBS. This may be attributable to affective disturbances, negative emotions in anticipation of or during visceral stimulation, and altered pain-related expectations and learning processes. Disturbed "top-down" emotional and cognitive pain modulation in IBS is reflected by functional and possibly structural brain changes involving prefrontal as well as cingulate regions. At the same time, there is growing evidence linking peripheral and mucosal immune changes and abdominal pain in IBS, supporting disturbed peripheral pain signalling. Findings in post-infectious IBS emphasize the interaction between centrally-mediated psychosocial risk factors and local inflammation in predicting long-term IBS symptoms. Investigating afferent immune-to-brain communication in visceral hyperalgesia as a component of the sickness response constitutes a promising future research goal.

Solid lipid nanoparticles as anti-inflammatory drug delivery system in a human inflammatory bowel disease whole-blood model

Standard treatment for inflammatory bowel diseases (IBD) necessitates frequent intake of anti-inflammatory and/or immunosuppressive drugs, leading to significant adverse events. To evaluate the role solid lipid nanoparticles (SLN) play as drug delivery system in enhancing anti-inflammatory activity for drugs such as dexamethasone and butyrate in a human inflammatory bowel diseases whole-blood model. ELISA assay and the peripheral blood mononuclear cell (PBMC) cytokine mRNA expression levels were evaluated by quantitative SYBR Green real-time RT-PCR to determine the IL-1beta, TNF-alpha, IFN-gamma and IL-10 secretion in inflammatory bowel diseases patients' PBMC culture supernatants. There was a significant decrease in IL-1beta (p<0.01) and TNF-alpha (p<0.001) secretion, whilst IL-10 (p<0.05) secretion significantly increased after cholesteryl butyrate administration, compared to that of butyrate alone at the highest concentration tested (100 microM), at 24h exposure. There was a significant decrease in IL-1beta (p<0.01), TNF-alpha (p<0.001) and IL-10 (p<0.001) secretion after dexamethasone loaded SLN administration, compared to dexamethasone alone at the highest concentration tested (250 nM) at 24h exposure. No IFN-gamma was detected under any conditions and no cytotoxic effects observed even at the highest concentration tested. The incorporation of butyrate and dexamethasone into SLN has a significant positive anti-inflammatory effect in the human inflammatory bowel disease whole-blood model.

Advances in the pathogenesis of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a highly prevalent functional gastrointestinal disorder in the world. Although previous studies have led to a greater understanding of the underlying pathophysiology of IBS, the mechanisms underlying the development of IBS are complex and still unclear. It is currently known that a variety of factors contribute to the development of IBS. Abnormal gastrointestinal motility and visceral hypersensitivity are thought to be the pathophysiological basis of the disease. In this article, we will review the recent advances in the pathogenesis of irritable bowel syndrome.

Changes in salivary physiological stress markers induced by muscle stretching in patients with irritable bowel syndrome

Background

Psychophysiological processing has been reported to play a crucial role in irritable bowel syndrome (IBS) but there has been no report on modulation of the stress marker chromogranin A (CgA) resulting from muscle stretching. We hypothesized that abdominal muscle stretching as a passive operation would have a beneficial effect on a biochemical index of the activity of the sympathetic/adrenomedullary system (salivary CgA) and anxiety.

Methods

Fifteen control and eighteen untreated IBS subjects underwent experimental abdominal muscle stretching for 4 min. Subjects relaxed in a supine position with their knees fully flexed while their pelvic and trunk rotation was passively and slowly moved from 0 degrees of abdominal rotation to about 90 degrees or the point where the subject reported feeling discomfort.

Changes in the Gastrointestinal Symptoms Rating Scale (GSRS), State Trait Anxiety Inventory (STAI), Self-rating Depression Scale (SDS), ordinate scale and salivary CgA levels were compared between controls and IBS subjects before and after stretching. A three-factor analysis of variance (ANOVA) with period (before vs. after) as the within-subject factor and group (IBS vs. Control), and sex (men vs. female) as the between-subject factors was carried out on salivary CgA.

Results

CgA showed significant interactions between period and groups (F[1, 31] = 4.89, p = 0.03), and between groups and sex (F[1, 31] = 4.73, p = 0.03). Interactions between period and sex of CgA secretion were not shown (F[1, 3] = 2.60, p = 0.12). At the baseline, salivary CgA in IBS subjects (36.7 ± 5.9 pmol/mg) was significantly higher than in controls (19.9 ± 5.5 pmol/mg, p < 0.05). After the stretching, salivary CgA significantly decreased in the IBS group (25.5 ± 4.5 pmol/mg), and this value did not differ from that in controls (18.6 ± 3.9 pmol/mg).

Conclusion

Our results suggest the possibility of improving IBS pathophysiology by passive abdominal muscle stretching as indicated by CgA, a biochemical index of the activity of the sympathetic/adrenomedullary system.

Progress in mechanisms of visceral hypersensitivity in irritable bowel syndrome

AIM: Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by abdominal discomfort and altered bowel habits. The mechanism of IBS is complex and remains unclear. Both central and peripheral factors, including psychosocial factors, abnormal gastrointestinal motility and secretion, and visceral hypersensitivity, are thought to contribute to the symptoms of IBS. Importantly, several external and internal factors can modulate visceral sensitivity, as well as gastrointestinal motility, and then lead to enhanced responses within the GI tract to, for instance, stress and nutrients. Visceral hypersensitivity is currently considered to be perhaps the most important pathophysiological factor in IBS, but the exact mechanism remains unknown. A variety of different mechanisms in brain-gut axis, alone or in combination, may be responsible for visceral hypersensitivity. In this article, we review the studies on the abnormal structure and/or function of enteric neuron system, spinal cord and cerebral system in IBS.

Stress-related peripheral neuroendocrine-immune interactions in women with ulcerative colitis

OBJECTIVES

The mechanisms underlying the interaction of psychological stress with the disease course in inflammatory bowel diseases remain unclear. We analyzed the neuroendocrine and cellular immune responses to public speaking stress, and the in vitro adrenergic and glucocorticoid modulation of cytokine production by peripheral blood cells (PBCs) in women with ulcerative colitis (UC) compared to healthy female controls.

METHODS

In 22 female UC patients with inactive disease or mild disease activity and 24 healthy females we analyzed the neuroendocrine and cellular immune responses to public speaking stress and the vitro beta-adrenergic and glucocorticoid regulation of IL-10 and TNF-alpha production by PBCs.

RESULTS

Public speaking stress-induced neuroendocrine and sympatho-adrenal activation, as well as the redistribution of circulating leukocytes were comparable in UC and controls. Significant but comparable public speaking stress-induced increases in LPS-stimulated TNF-alpha and IL-10, as well as in CD2/CD28-stimulated IFN-gamma were observed in both groups. UC demonstrated significantly reduced baseline IFN-gamma production, as well as significantly lower basal cortisol and prolactin levels. The in vitro beta-adrenergic stimulation of PBCs revealed reduced IL-10 response in UC.

CONCLUSIONS

Psychosocial stress-induced activation of the neuroendocrine and sympatho-adrenal systems remain unaltered in UC, suggesting that the mechanism(s) mediating effects of psychological stress on disease activity are likely operative downstream at the level of the intestine. However, UC patients show disturbances in basal endocrine and cytokine measures. Together with our in vitro evidence of disturbed adrenergic regulation of IL-10 production by stimulated PBCs in UC, these may indicate the existence of subtle disturbance of peripheral cellular neuroendocrine-immune interactions in UC.