Pain and inflammatory bowel disease

The pharmacological blockade of P2X4 receptor as a viable approach to manage visceral pain in a rat model of colitis

Nowadays, the pharmacological management of visceral hypersensitivity associated with colitis is ineffective. In this context, targeting purinergic P2X4 receptor (P2X4R), which can modulate visceral pain transmission, could represent a promising therapeutic strategy. Herein, we tested the pain-relieving effect of two novel and selective P2X4R antagonists (NC-2600 and NP-1815-PX) in a murine model of DNBS-induced colitis and investigated the mechanisms underlying their effect. Tested drugs and dexamethasone (DEX) were administered orally, two days after colitis induction. Treatment with tested drugs and DEX improved tissue inflammatory parameters (body weight, spleen weight, macroscopic damage, TNF and IL-1β levels) in DNBS-rats. In addition, NC-2600 and NP-1815-PX attenuated visceral pain better than DEX and prevented the reduction of occludin expression. In in vitro studies, treatment of CaCo2 cells with supernatant from THP-1 cells, previously treated with LPS plus ATP, reduced the expression of tight junctions protein. By contrast, CaCo2 cells treated with supernatant from THP-1 cells, previously incubated with tested drugs, counteracted the reduction of tight junctions due to the inhibition of P2X4R/NLRP3/IL-1β axis. In conclusion, these results suggest that the direct and selective inhibition of P2X4R represents a viable approach for the management of visceral pain associated with colitis via NLRP3/IL-1β axis inhibition.

Editorial: Surgery to reduce opioid use in Crohn's disease: Does a classic solution address a newer problem?

This article is linked to Norgard et al paper. To view this article, visit https://doi.org/10.1111/apt.18014

The Burden of Work Productivity and Activity Impairment in Patients with Psoriasis, Psoriatic Arthritis, Ulcerative Colitis, and Crohn's Disease

BACKGROUND

Comparisons among autoimmune diseases enable understanding of the burden and factors associated with work productivity loss and impairment.

AIMS

The objective was to compare work productivity and activity and associated factors among patients with inflammatory bowel diseases and other autoimmune conditions.

METHODS

This cross-sectional study included employed, adult patients (age 20-64 years) in the CorEvitas Inflammatory Bowel Disease, Psoriasis, and Psoriatic Arthritis/Spondyloarthritis Registries between 5/2017 and 6/2020. Any patient-reported impairment on four domains of the Work Productivity and Activity Index (WPAI) was collected across registries. Prevalence for each autoimmune disease was reported and stratified by disease activity using direct age-sex-standardization. Factors associated with the presence of any WPAI were identified in logistic regression models.

RESULTS

A total of 7,169 patients with psoriasis (n = 4,768, 67%), psoriatic arthritis (n = 1,208, 17%), Crohn's disease (CD, n = 621, 9%), and ulcerative colitis (UC, n = 572, 8%) met inclusion criteria. Among patients not in remission across all disease cohorts, the age-sex-standardized prevalence of any presenteeism, work productivity loss, and activity impairment ranged from 54 to 97%. Patients with CD in remission had higher standardized prevalence of presenteeism (53% [48-57%]) and work productivity loss (54% [49-59%]), compared to those from other cohorts (presenteeism [range: 33-39%] and work productivity loss [range: 37-41%]). For all WPAI domains, the strongest adjusted associations were for moderate to severe disease activity and psychosocial symptoms.

CONCLUSIONS

Patients with moderate to severe disease activity reported the highest WPAI burden. However, patients in remission or mild disease activity also report some WPAI burden, emphasizing a multidisciplinary treatment approach to improve work productivity loss and impairment.

Moxibustion ameliorates chronic inflammatory visceral pain via spinal circRNA-miRNA-mRNA networks: a central mechanism study

This study aimed to unveil the central mechanism of moxibustion treating chronic inflammatory visceral pain (CIVP) from the angle of circRNA-miRNA-mRNA networks in the spinal cord. The rat CIVP model was established using a mixture of 5% (w/v) 2,4,6-trinitrobenzene sulfonic acid and 50% ethanol at a volume ratio of 2:1 via enema. Rats in the moxibustion group received herb-partitioned moxibustion at Tianshu (ST25, bilateral) and Qihai (CV6) points. The abdominal withdrawal reflex (AWR), mechanical withdrawal threshold (MWT), and thermal withdrawal latency (TWL) were adopted for pain behavior observation and pain sensitivity assessment. The circRNA, miRNA, and mRNA expression profiles were detected using the high-throughput sequencing technique. Relevant databases and bioinformatics analysis methods were used to screen for differentially expressed (DE) RNAs and build a circRNA-miRNA-mRNA (competing endogenous RNA) ceRNA regulatory network. The real-time quantitative PCR was employed to verify the sequencing result. CIVP rat models had a significantly higher AWR and lower TWL and MWT than normal rats. Between normal and model rats, there were 103 DE-circRNAs, 16 DE-miRNAs, and 397 DE-mRNAs in the spinal cord. Compared with the model group, the moxibustion group had a lower AWR and higher TWL and MWT; between these two groups, there were 118 DE-circRNAs, 15 DE-miRNAs, and 804 DE-mRNAs in the spinal cord. Two ceRNA networks were chosen to be verified. As a result, moxibustion's analgesic effect on visceral pain in CIVP rats may be associated with regulating the circRNA_02767/rno-miR-483-3p/Gfap network in the spinal cord and improving central sensitization.

The Gut Microbiota and Chronic Pain

PURPOSE OF REVIEW

To examine the effects and interactions between gut microbia and chronic pain.

RECENT FINDINGS

The gut microbiome has been an area of interest in both the scientific and general audience due to a growing body of evidence suggesting its influence in a variety of health and disease states. Communication between the central nervous system (CNS) and gut microbiome is said to be bidirectional, in what is referred to as the gut-brain axis. Chronic pain is a prevalent costly personal and public health burden and so, there is a vested interest in devising safe and efficacious treatments. Numerous studies, many of which are animal studies, have been conducted to examine the gut microbiome's role in the pathophysiology of chronic pain states, such as neuropathy, inflammation, visceral pain, etc. As the understanding of this relationship grows, so does the potential for therapeutic targeting of the gut microbiome in chronic pain.

Experimental colitis-induced visceral hypersensitivity is attenuated by GABA treatment in mice

Ulcerative colitis (UC) is linked with inflammation of the large intestine due to an overactive response of the colon-immune system. UC is associated with weight loss, rectal bleeding, diarrhea, and abdominal pain. Given that γ-amino butyric acid (GABA) suppresses immune cell activity and the excitability of colonic afferents, and that there is a decrease in colonic GABA during UC, we hypothesized that UC pain is due to a decrease in the inhibition of colonic afferents. Thus, restoring GABA in the colon will attenuate inflammatory hypersensitivity. We tested this hypothesis in a mouse model of colitis. Colon inflammation was induced with seven days of dextran sodium sulfate (DSS, 3%) in the drinking water. GABA (40 mg/kg) was administered orally for the same period as DSS, and body weight, colon length, colon permeability, clinical progression of colitis (disease activity index or DAI), and colon histological score (HS) were assessed to determine the effects of GABA on colitis. A day after the end of GABA treatment, visceral sensitivity was assessed with balloon distention (of the colon)-evoked visceromotor response and colon samples were collected for the measurement of GABA and cytokines. Treatment with GABA reduced the DSS-induced increase in the colon permeability, DAI, HS, and decrease in body weight and colon length. Furthermore, GABA inhibited the DSS-induced increase in the proinflammatory cytokines tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-12 (IL-12), and increased the expression of the anti-inflammatory cytokine IL-10 in the colon tissue. Importantly, GABA reduced DSS-induced visceral hypersensitivity. These data suggest that increasing gastrointestinal levels of GABA may be useful for the treatment of colitis.NEW & NOTEWORTHY GABA treatment reduces the severity of colitis and inflammation and produces inhibition of visceral hypersensitivity in colon-inflamed mice. These results raise the promising possibility that GABA treatment may be an effective therapeutic strategy for the management of symptoms associated with colitis. However, clinical studies are required to corroborate whether this mouse-model data translates to human colon.

The role of purinergic signaling in acupuncture-mediated relief of neuropathic and inflammatory pain

Acupuncture is a traditional medicinal practice in China that has been increasingly recognized in other countries in recent decades. Notably, several reports have demonstrated that acupuncture can effectively aid in pain management. However, the analgesic mechanisms through which acupuncture provides such benefits remain poorly understood. Purinergic signaling, which is mediated by purine nucleotides and purinergic receptors, has been proposed to play a central role in acupuncture analgesia. On the one hand, acupuncture affects the transmission of nociception by increasing adenosine triphosphate dephosphorylation and thereby decreasing downstream P2X3, P2X4, and P2X7 receptors signaling activity, regulating the levels of inflammatory factors, neurotrophic factors, and synapsin I. On the other hand, acupuncture exerts analgesic effects by promoting the production of adenosine, enhancing the expression of downstream adenosine A1 and A2A receptors, and regulating downstream inflammatory factors or synaptic plasticity. Together, this systematic overview of the field provides a sound, evidence-based foundation for future research focused on the application of acupuncture as a means of relieving pain.

Expression and function of transient receptor potential melastatin 3 in the spinal afferent innervation of the mouse colon

Abdominal pain is a cardinal symptom of inflammatory bowel disease (IBD). Transient receptor potential (TRP) channels contribute to abdominal pain in preclinical models of IBD, and TRP melastatin 3 (TRPM3) has recently been implicated in inflammatory bladder and joint pain in rodents. We hypothesized that TRPM3 is involved in colonic sensation and is sensitized during colitis. We used immunohistochemistry, ratiometric Ca2+ imaging, and colonic afferent nerve recordings in mice to evaluate TRPM3 protein expression in colon-projecting dorsal root ganglion (DRG) neurons, as well as functional activity in DRG neurons and colonic afferent nerves. Colitis was induced using dextran sulfate sodium (DSS) in drinking water. TRPM3 protein expression was observed in 76% of colon-projecting DRG neurons and was often colocalized with calcitonin gene-related peptide. The magnitudes of intracellular Ca2+ transients in DRG neurons in response to the TRPM3 agonists CIM-0216 and pregnenolone sulfate sodium were significantly greater in neurons from mice with colitis compared with controls. In addition, the percentage of DRG neurons from mice with colitis that responded to CIM-0216 was significantly increased. CIM-0216 also increased the firing rate of colonic afferent nerves from control and mice with colitis. The TRPM3 inhibitor isosakuranetin inhibited the mechanosensitive response to distension of wide dynamic range afferent nerve units from mice with colitis but had no effect in control mice. Thus, TRPM3 contributes to colonic sensory transduction and may be a potential target for treating pain in IBD.NEW & NOTEWORTHY This is the first study to characterize TRPM3 protein expression and function in colon-projecting DRG neurons. A TRPM3 agonist excited DRG neurons and colonic afferent nerves from healthy mice. TRPM3 agonist responses in DRG neurons were elevated during colitis. Inhibiting TRPM3 reduced the firing of wide dynamic range afferent nerves from mice with colitis but had no effect in control mice.

'Symptom-free' when inflammatory bowel disease is in remission: Expectations raised by online resources

OBJECTIVES

Up to 60% of patients with inflammatory bowel disease (IBD) experience symptoms when in remission. Qualitative research suggests patients seldom feel they receive adequate explanations for these. This study explores how, and how often, ongoing symptoms during remission are represented on readily searchable patient websites.

METHODS

Bing, Google, and Yahoo were searched for websites providing medical information about IBD. Thematic analysis was used to inductively explore themes around symptoms during quiescent IBD, followed by deductive content analysis to quantify core themes.

RESULTS

Results indicated that remission is commonly defined as "few or no symptoms" and that there is limited information available on symptoms during remission. 55.6% of IBD websites provided a definition of remission based on symptom control only, while 44.4% also incorporated inflammatory control. The few websites that mentioned that symptoms may continue during remission (21.7%) related these to IBS.

CONCLUSIONS

Current website information is predominantly biomedical and fails to adequately explain how symptoms may persist during remission and how IBS and IBD may be linked.

PRACTICE IMPLICATIONS

Lack of explanatory models of symptoms in remission may lead to distress and increase anxiety about symptoms. Clearer explanations of these symptoms are needed.

Making sense of pain in inflammatory bowel disease (IBD): A qualitative study

OBJECTIVES

Inflammatory bowel disease (IBD) is a chronic, gastrointestinal tract condition, in which pain is one of the most widespread and debilitating symptoms, yet research about how individuals make sense of their IBD pain is lacking. The current study aimed to explore how individuals with IBD understand their pain.

METHODS

Twenty participants, recruited via the Crohn's & Colitis UK charity, were interviewed about their understanding of their IBD pain using the Grid Elaboration Method that elicits free associations on which it invites elaboration. Thematic analysis was used to organise transcribed verbatim data.

RESULTS

Three related themes - making sense of my pain, navigating my care and support and it takes its toll - comprising seven sub-themes, illustrated the ways in which participants made sense of pain experientially, multi-dimensionally, and in the broader context of IBD and its symptoms. The psychological impact of pain was evident across all interviews.

CONCLUSIONS

The findings are consistent with other research in IBD pain, demonstrating the importance of pain in IBD. Sense-making underpins both emotional and practical responses to pain and ideally is constructed as an integral part of clinical care of IBD.

Fatigue in Patients with Newly Diagnosed Inflammatory Bowel Disease: Results from a Prospective Inception Cohort, the IBSEN III Study

BACKGROUND AND AIMS

Although fatigue is common in inflammatory bowel disease [IBD], its pathogenesis remains unclear. This study aimed to determine the prevalence of fatigue and its associated factors in a cohort of patients newly diagnosed with IBD.

METHODS

Patients ≥18 years old were recruited from the Inflammatory Bowel Disease South-Eastern Norway [IBSEN III] study, a population-based, observational inception cohort. Fatigue was assessed using the Fatigue Questionnaire and compared with data from a Norwegian general population. Univariate and multivariate linear and logistic regression analyses were performed to evaluate the associations of total fatigue [TF; continuous score] and substantial fatigue [SF; dichotomized score ≥4] with sociodemographic, clinical, endoscopic, laboratory, and other relevant patient data.

RESULTS

In total, 983/1509 [65.1%] patients with complete fatigue data were included (ulcerative colitis [UC], 68.2%; Crohn's disease [CD], 31.8%). The prevalence of SF was higher in CD [69.6%] compared with UC [60.2%] [p < 0.01], and in both diagnoses when compared to the general population [p < 0.001]. In multivariate analyses, depressive symptoms, pain intensity, and sleep disturbances were associated with increased TF for both diagnoses. In addition, increased clinical disease activity and Mayo endoscopic score were significantly associated with TF in UC, whereas all disease-related variables were insignificant in CD. Similar findings were observed for SF, except regarding the Mayo endoscopic score.

CONCLUSIONS

SF affects approximately two-thirds of patients newly diagnosed with IBD. Fatigue was associated with depressive symptoms, sleep disturbances, and increased pain intensity in both diagnoses, while clinical and endoscopic activity were associated factors only in UC.

The Prokineticin System in Inflammatory Bowel Diseases: A Clinical and Preclinical Overview

Inflammatory bowel disease (IBD) includes Crohn's disease (CD) and ulcerative colitis (UC), which are characterized by chronic inflammation of the gastrointestinal (GI) tract. IBDs clinical manifestations are heterogeneous and characterized by a chronic relapsing-remitting course. Typical gastrointestinal signs and symptoms include diarrhea, GI bleeding, weight loss, and abdominal pain. Moreover, the presence of pain often manifests in the remitting disease phase. As a result, patients report a further reduction in life quality. Despite the scientific advances implemented in the last two decades and the therapies aimed at inducing or maintaining IBDs in a remissive condition, to date, their pathophysiology still remains unknown. In this scenario, the importance of identifying a common and effective therapeutic target for both digestive symptoms and pain remains a priority. Recent clinical and preclinical studies have reported the prokineticin system (PKS) as an emerging therapeutic target for IBDs. PKS alterations are likely to play a role in IBDs at multiple levels, such as in intestinal motility, local inflammation, ulceration processes, localized abdominal and visceral pain, as well as central nervous system sensitization, leading to the development of chronic and widespread pain. This narrative review summarized the evidence about the involvement of the PKS in IBD and discussed its potential as a druggable target.

CPW partially attenuates DSS-induced ulcerative colitis in mice

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) of the gastrointestinal tract. The etiology is not fully understood, but environmental, microbial, and immunologic factors, as well as a genetic predisposition, play a role. UC is characterized by episodes of abdominal pain, diarrhea, bloody stools, weight loss, severe colonic inflammation, and ulceration. Despite the increase in the frequency of UC and the deterioration of the quality of life, there are still patients who do not respond well to available treatment options. Against this background, natural products such as polysaccharides are becoming increasingly important as they protect the intestinal mucosa, promote wound healing, relieve inflammation and pain, and restore intestinal motility. In this study, we investigated the effect of a polysaccharide isolated from the biomass of Campomanesia adamantium and Campomanesia pubescens (here referred to as CPW) in an experimental model of acute and chronic ulcerative colitis induced by dextran sulfate sodium (DSS). CPW reversed weight loss, increased disease activity index (DAI), bloody diarrhea, and colon shortening. In addition, CPW reduced visceral mechanical hypersensitivity, controlled oxidative stress and inflammation, and protected the mucosal barrier. CPW is not absorbed in the intestine, does not inhibit cytochrome P450 proteins, and does not exhibit AMES toxicity. These results suggest that CPW attenuates DSS-induced acute and chronic colitis in mice and may be a potential alternative treatment for UC.

Lifestyle Factors Associated with Abdominal Pain in Quiescent Inflammatory Bowel Disease

BACKGROUND

Lifestyle factors, including diet, exercise, substance use, and sexual activity, have been shown to influence risk of inflammation and complications in inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC). Little is known about their potential role in abdominal pain generation in IBD.

AIMS

We performed this study to evaluate for relationships between lifestyle factors and abdominal pain in quiescent IBD (QP-IBD).

METHODS

We performed a retrospective analysis utilizing data from our institution's IBD Natural History Registry (January 1, 2017-December 31, 2022). Endoscopic evaluation, concurrent laboratory studies and surveys were completed by participants. Demographic and clinical data were also abstracted.

RESULTS

We identified 177 consecutive patients with quiescent disease (105 females:72 males; 121 with CD:56 with UC) for participation in this study, 93 (52.5%) had QP-IBD. Compared to patients with quiescent IBD without pain (QNP-IBD, patients with QP-IBD exhibited no significant differences in IBD type, location, severity or complication rate. Patients with QP-IBD were more likely to have anxiety/depression (55.9% vs. 32.1%, p = 0.002) and to use antidepressants/anxiolytics (49.5% vs. 21.4%, p < 0.001). They were also less likely to engage in exercise at least three times per week (39.8% vs. 54.8%, p = 0.05) or participate in sexual activity at least monthly (53.8% vs. 69.1%, p = 0.04). On logistic regression analysis, antidepressant and/or anxiolytic use was independently associated with QP-IBD [2.72(1.32-5.62)], while monthly sexual activity was inversely associated [0.48(0.24-0.96)].

CONCLUSION

Lifestyle factors, including the lack of sexual activity and exercise, are significantly associated with QP-IBD. Further study is warranted to clarify the relationships between these factors and the development of abdominal pain in quiescent IBD.

Abdominal Pain in Inflammatory Bowel Disease: An Evidence-Based, Multidisciplinary Review

Abdominal pain is one of the most common and impactful symptoms associated with inflammatory bowel disease (IBD), including both Crohn's disease and ulcerative colitis. A great deal of research has been undertaken over the past several years to improve our understanding and to optimize management of this issue. Unfortunately, there is still significant confusion about the underlying pathophysiology of abdominal pain in these conditions and the evidence underlying treatment options in this context. There is also a relative paucity of comprehensive reviews on this topic, including those that simultaneously evaluate pharmacological and nonpharmacological therapeutic options. In this review, our multidisciplinary team examines evidence for various currently available medical, surgical, and other analgesic options to manage abdominal pain in IBD.

Evaluation of the effect of tramadol, paracetamol and metamizole on the severity of experimental colitis

Application of dextran sodium sulfate (DSS) is often used to induce experimental colitis. Current state of the art is to refrain from the use of analgesics due to their possible interaction with the model. However, the use of analgesics would be beneficial to reduce the overall constraint imposed on the animals. Here, we analyzed the effect of the analgesics Dafalgan (paracetamol), Tramal (tramadol) and Novalgin (metamizole) on DSS-induced colitis. To study the effect of those analgesics in colitis mouse models, acute and chronic colitis was induced in female C57BL6 mice by DSS administration in the drinking water. Analgesics were added to the drinking water on days four to seven (acute colitis) or on days six to nine of each DSS cycle (chronic colitis). Tramadol and paracetamol had minor effects on colitis severity. Tramadol reduced water uptake and activity levels slightly, while mice receiving paracetamol presented with a better overall appearance. Metamizole, however, significantly reduced water uptake, resulting in pronounced weight loss. In conclusion, our experiments show that tramadol and paracetamol are viable options for the use in DSS-induced colitis models. However, paracetamol seems to be slightly more favorable since it promoted the overall wellbeing of the animals upon DSS administration without interfering with typical readouts of colitis severity.

Research hotspots and trend analysis of abdominal pain in inflammatory bowel disease: a bibliometric and visualized analysis

Aims: The study aimed to provide a bibliometric and visual analysis of research on abdominal pain in inflammatory bowel disease and discuss the current status, research hotspots, and future developments. Methods: We used the Web of Science Core Collection to comprehensively search the literature on abdominal pain-related research in IBD published between 2003 and 2022. The bibliometric and visual analysis was performed through CiteSpace, VOSviewer software, R language, and the bibliometric online analysis platform, including authors, institutions, countries, journals, references, and keywords in the literature. Results: A total of 3,503 relevant articles are included, indicating that the number of articles in this field has increased in recent years. The United States leads the way with a dominant position in terms of article output, followed by China and JAPAN. United States (967 articles), University of Calgary (98 articles), and World Journal of Gastroenterology (127 articles) are the top publishing countries, institutions, and journals, respectively; keyword analysis shows that gut microbiota, depression, stress, visceral hypersensitivity, and multidisciplinary approach are the hot spots and trends in this research area. Conclusion: Abdominal pain-related studies in IBD have received increasing attention in the past two decades. This study provides the first bibliometric analysis of papers in this research area using visualization software and data information mining. It provides insights into this field's current status, hot spots, and trends. However, many outstanding issues in this research area still need further exploration to provide a theoretical basis for its clinical application.

Characterization of prokineticin system in Crohn's disease pathophysiology and pain, and its modulation by alcohol abuse: A preclinical study

BACKGROUND

Crohn's disease-(CD) pathogenesis is still unknown and chronic pain is a frequent symptom in CD-patients. Identifying novel therapeutic targets and predisposing factors is a primary goal. In this regard, prokineticin system-(PKS) appears a promising target.

AIMS AND METHODS

TNBS-model was used. DAI, abdominal and visceral pain, and muscle strength were monitored. CD-mice were sacrificed at two times (day 7 and 14 after TNBS) in order to identify PKS involvement in CD pathophysiology and pain. PKS characterization was performed in mesenteric lymph nodes-(MLN), colon, myenteric plexus-(MP), dorsal root ganglia-(DRGs) and spinal cord-(SC). Inflammation/neuroinflammation was also assessed in the same tissues. In order to evaluate alcohol abuse as a possible trigger for CD and its effect on PKS activation, naïve mice were administered (oral-gavage) with ethanol for 10 consecutive days. PKS as well as inflammation/neuroinflammation were evaluated in MLN, colon and MP.

RESULTS

TNBS treated-mice showed a rapid increase in DAI, abdominal/visceral hypersensitivity and a progressive strength loss. In all tissue analysed of CD-mice, a quick and significant increase of mRNA of PKs and PKRs was observed, associated with an increase of pro-inflammatory cytokines (IL-1β, IL-6 and TNFα) and macrophage/glia markers (iba1, CD11b and GFAP) levels. In alcohol abuse model, ethanol induced in colon and MP a significant PKS activation accompanied by inflammation/neuroinflammation.

CONCLUSIONS

We can assume that PKS may be involved in CD development and pain. Furthermore, alcohol appears to activate PKS and may be a trigger factor for CD.

Randomised clinical trial: Psychological intervention improves work productivity and daily activity by reducing abdominal pain and fatigue in Crohn's disease

BACKGROUND

Chronic abdominal pain and fatigue are characteristics of Crohn's disease (CD) and contribute to functional impairments.

AIMS

To examine whether CD-tailored cognitive-behavioural and mindfulness intervention (COBMINDEX) is effective in reducing abdominal pain and fatigue in patients with CD and whether changes in abdominal pain and fatigue mediate any beneficial effects of COBMINDEX on impairments in work productivity and daily activities.

METHODS

This is a secondary analysis of a parallel-group multicentre randomised controlled trial. Patients with mild-to-moderate CD (n = 142) were randomised into either intervention group receiving COBMINDEX, or control group receiving treatment-as-usual for 3 months followed by COBMINDEX. Complete data were collected from 120 patients (34.0 ± 10.7 years, 62.5% female, intervention = 60, control = 60). Analysis of covariance assessed group differences in 3-month follow-up scores, controlling for baseline scores. Multiple parallel mediation analysis assessed the proposed mechanisms for the entire sample.

RESULTS

The intervention group demonstrated significantly lower levels of abdominal pain (F = 17.46, p < 0.001, η² _p  = 0.13), fatigue (F = 7.26, p = 0.008, η² _p  = 0.06) and impairments at work (F = 4.82, p = 0.032, η² _p  = 0.07) and daily activities (F = 6.26, p = 0.014, η² _p  = 0.05), compared with treatment-as-usual. Moreover, changes in abdominal pain and fatigue significantly mediated the beneficial effects of COBMINDEX on patients' work productivity (b = -9.90, SE = 2.86, 95% CI: -16.11 to -4.94) and daily activities (b = -9.65, SE = 1.91, 95% CI: -13.77 to 6.35), independent of changes in disease activity.

CONCLUSIONS

COBMINDEX is effective at reducing abdominal pain and fatigue in patients with CD, which in turn leads to improvement in functioning. Clinicians should incorporate screening for severe abdominal pain and fatigue and consider offering cognitive-behavioural and mindfulness training.

CLINICALTRIALS

gov, Number: NCT05085925. Ministry of Health in Israel (https://my.health.gov.il/CliniTrials/Pages/MOH_2020-02-24_008721.aspx).

Acute Administration of Ojeok-san Ameliorates Pain-like Behaviors in Pre-Clinical Models of Inflammatory Bowel Diseases

(1) Background: Gastrointestinal pain and fatigue are the most reported concerns of patients with inflammatory bowel disease (IBD). Commonly prescribed drugs focus on decreasing excessive inflammation. However, up to 20% of IBD patients in an "inactive" state experience abdominal pain. The medicinal herb Ojeok-san (OJS) has shown promise in the amelioration of visceral pain. However, no research on OJS has been conducted in preclinical models of IBD. The mechanism by which OJS promotes analgesia is still elusive, and it is unclear if OJS possesses addictive properties. (2) Aims: In this study, we examined the potential of OJS to promote analgesic effects and rewarding behavior. Additionally, we investigated if tumor necrosis factor alpha (TNFα) from macrophages is a primary culprit of IBD-induced nociception. (3) Methods: Multiple animal models of IBD were used to determine if OJS can reduce visceral nociception. TNFα-macrophage deficient mice were used to investigate the mechanism of action by which OJS reduces nociceptive behavior. Mechanical sensitivity and operant conditioning tests were used to determine the analgesic and rewarding effects of OJS. Body weight, colon length/weight, blood in stool, colonic inflammation, and complete blood count were assessed to determine disease progression. (4) Results: OJS reduced the evoked mechanical nociception in the dextran sulphate sodium model of colitis and IL-10 knockout (KO) mice and delayed aversion to colorectal distension in C57BL/6 mice. No rewarding behavior was observed in OJS-treated IL-10 KO and mdr1a KO mice. The analgesic effects of OJS are independent of macrophage TNFα levels and IBD progression. (5) Conclusions: OJS ameliorated elicited mechanical and visceral nociception without producing rewarding effects. The analgesic effects of OJS are not mediated by macrophage TNFα.

Inhibition of Canonical Transient Receptor Potential Channels 4/5 with Highly Selective and Potent Small-Molecule HC-070 Alleviates Mechanical Hypersensitivity in Rat Models of Visceral and Neuropathic Pain

Transient receptor potential channels C4/C5 are widely expressed in the pain pathway. Here, we studied the putative analgesic efficacy of the highly selective and potent TRPC4/C5 antagonist HC-070 in rats. Inhibitory potency on human TRPC4 was assessed by using the whole-cell manual patch-clamp technique. Visceral pain sensitivity was assessed by the colonic distension test after intra-colonic trinitrobenzene sulfonic acid injection and partial restraint stress. Mechanical pain sensitivity was assessed by the paw pressure test in the chronic constriction injury (CCI) neuropathic pain model. We confirm that HC-070 is a low nanomolar antagonist. Following single oral doses (3-30 mg/kg in male or female rats), colonic hypersensitivity was significantly and dose-dependently attenuated, even fully reversed to baseline. HC-070 also had a significant anti-hypersensitivity effect in the established phase of the CCI model. HC-070 did not have an effect on the mechanical withdrawal threshold of the non-injured paw, whereas the reference compound morphine significantly increased it. Analgesic effects are observed at unbound brain concentrations near the 50% inhibitory concentration (IC₅₀) recorded in vitro. This suggests that analgesic effects reported here are brought about by TRPC4/C5 blocking in vivo. The results strengthen the idea that TRPC4/C5 antagonism is a novel, safe non-opioid treatment for chronic pain.

Electroacupuncture Alleviates 46-Trinitrobenzene Sulfonic Acid-Induced Visceral Pain via the Glutamatergic Pathway in the Prefrontal Cortex

Visceral pain caused by inflammatory bowel disease (IBD) greatly diminishes the quality of life in affected patients. Yet, the mechanism of how IBD causes visceral pain is currently not fully understood. Previous studies have suggested that the central nervous system (CNS) and gut-brain axis (GBA) play an important role in IBD-inducing visceral pain. As one of the treatments for IBD, electroacupuncture (EA) has been used to treat various types of pain and gastrointestinal diseases in clinical practice. However, whether EA relieves the visceral pain of IBD through the gut-brain axis has not been confirmed. To verify the relationship between visceral pain and CNS, the following experiments were conducted. ¹H-NMR analysis was performed on the prefrontal cortex (PFC) tissue obtained from IBD rat models to determine the link between the metabolites and their role in EA treatment against visceral pain. Western blot assay was employed for detecting the contents of glutamate transporter excitatory amino acid transporters 2 (EAAT2) and the glutamate receptor N-methyl-D-aspartate (NMDA) to verify whether EA treatment can alleviate neurotoxic symptoms induced by abnormal increases of glutamate. Study results showed that the glutamate content was significantly increased in the PFC of TNBS-induced IBD rats. This change was reversed after EA treatment. This process was associated with increased EAAT2 expression and decreased expression of NMDA receptors in the PFC. In addition, an increase in intestinal glutamic-metabolizing bacteria was observed. In conclusion, this study suggests that EA treatment can relieve visceral pain by reducing glutamine toxicity in the PFC, and serves an alternative clinical utility.

Management of Pelvic Pain in Patients with Crohn's Disease-Current Overview

Crohn's disease (CD) is a subtype of chronic inflammatory bowel diseases (IBD) with characteristic skip lesions and transmural inflammation that may affect the entire gastrointestinal tract from the mouth to the anus. Persistent pain is one of the main symptoms of CD. This pain has multifactorial pathogenesis, but most often arises from intestinal inflammation itself, as well as from gut distention or partial intestinal obstruction. Some current evidence also suggests sensitization of sensory pathways, as well as modulation of those signals by the central nervous system, which highlights the impact of biopsychosocial factors. To date, most studies have focused only on the pain located in the abdomen, while pelvic pain has rarely been explored, despite it being a common symptom. The aim of this study is to provide an abbreviated summary of the current state of knowledge on the origins and treatment of pelvic pain in CD.

Relationships Between Abdominal Pain, Mental Health, and Functional Disability in Youth With Inflammatory Bowel Diseases: Pain Catastrophizing as a Longitudinal Mediator

OBJECTIVES

Abdominal pain can be a debilitating symptom for youth with inflammatory bowel diseases (IBDs). Across various pediatric conditions, pain predicts adverse physical and mental health outcomes. Understanding mechanisms by which pain impacts outcomes is of critical importance to enhance the well-being of those with IBDs. Pain catastrophizing mediates the aforementioned relationships in other pediatric populations, but little research has examined its role in pediatric IBDs. Attention to the role of pain catastrophizing as a potential mediator in pediatric IBD is the important given unique elements of the pain experience for this population. This study aimed to examine pain catastrophizing as a potential mediator of the relationship between abdominal pain and adverse outcomes in youth with IBDs.

METHODS

Seventy six youth (ages 11 to 18; M [SD] age=14.71 [1.80]) with IBD completed the Abdominal Pain Index (T1), Pain Catastrophizing Scale (T2, week 12), Revised Children's Anxiety and Depression Scale (T3, week 20), and Functional Disability Inventory (T3, week 20).

RESULTS

Catastrophizing mediated the relationship between abdominal pain and both anxiety symptoms ( b =1.61, Bias-Corrected Accelerated [BCa] CI, 0.25, 4.62) and functional disability ( b =0.77, BCa CI, 0.15, 2.38). A direct effect of abdominal pain on low mood was also noted ( b =1.17, BCa CI, 0.03, 2.50). Post hoc analyses examining mediation via catastrophizing subscales indicated that while magnification and rumination functioned as mediators, helplessness did not.

DISCUSSION

Findings are consistent with fear avoidance models and suggest that interventions directed at pain catastrophizing may be worthwhile in pediatric IBD populations, given catastrophizing-mediated relationships between pain and mental and physical health outcomes.

Medication use among patients with Crohn’s disease or ulcerative colitis before and after the initiation of advanced therapy

Background

Although various treatments help reduce abdominal pain, real-world pain medication utilization among patients with Crohn’s disease (CD) or ulcerative colitis (UC) receiving advanced therapies is poorly understood. The aim is to understand the utilization of pain medication 12 months before and after the initiation of advanced therapies among patients with newly diagnosed CD or UC.

Methods

This retrospective, observational cohort study used administrative medical and pharmacy claims data of patients with CD or UC from HealthCore Integrated Research Database (HIRD®). The data from patients with use of pain medication over 12 months follow-up (after the initiation date of advanced therapies) were collected and analyzed. Differences in the use of pain medication 12 months before and after the initiation of advanced therapies were assessed using McNemar's and Wilcoxon signed-rank test.

Results

Prior to initiating advanced therapies, 23.1% of patients with CD (N = 540) received nonsteroidal anti-inflammatory drugs (NSAIDs), 78.1% glucocorticoids, 49.4% opioids, and 29.3% neuromodulators; similarly, 20.9% of patients with UC (N = 373) received NSAIDs, 91.4% glucocorticoids, 40.8% opioids, and 29.5% neuromodulators. After receiving advanced therapies for 12 months, patients reported a reduction in the use of steroids (78.1% vs. 58.9%, P < 0.001 in CD; 91.4% vs. 74.3%, P < 0.001 in UC), opioids (49.4% vs. 41.5%, P = 0.004 in CD; 40.8% vs. 36.5%, P = 0.194 in UC), and NSAIDs (23.1% vs. 15.0%, P < 0.001 in CD; 20.9% vs. 15.8%, P = 0.035 in UC), while the use of neuromodulators significantly increased (29.3% vs. 33.7%, P = 0.007 in CD; 29.5% vs. 35.7%; P = 0.006 in UC).

Conclusions

The use of pain medications such as NSAIDs, glucocorticoids, opioids, and neuromodulators was common among patients with CD or UC. These results highlight that patients with CD or UC continued to receive pain medications even after initiating advanced therapies.

Appraisals of Pain in Pediatric Inflammatory Bowel Disease: A Qualitative Study With Youth, Parents, and Providers

Background

Pain is a predominant symptom of inflammatory bowel disease (IBD), and is influenced by cognitive, emotional, and behavioral factors. The cognitive-affective model of symptom appraisal (CAMSA) has been used to understand how youth view symptoms in chronic conditions. We sought to (1) determine how youth with IBD and their parents appraise pain, and how their perspectives fit within CAMSA, and (2) explore health care providers' understanding and communication about pain.

Methods

Participants included 19 youth ages 10-17 years with chronic IBD pain and their parents, and 5 IBD providers from a gastroenterology clinic. Separate semi-structured qualitative interviews with youth, parents, and providers were conducted. Interview prompts were adapted from CAMSA, previous studies of pediatric pain and symptom monitoring, and a qualitative study in adults with IBD pain. Interviews were analyzed according to principles of reflexive thematic analysis.

Results

Three key components of CAMSA (IBD Threat, Fear/Worry, and Biased Attending) were identified in youth and parent dyads. Some youth showed Biased Attending, including difficulty disengaging, while other youth simply monitored pain. The overarching theme for provider interviews was Gastroenterologists view pain as a secondary (rather than primary) treatment issue.

Conclusions

CAMSA is potentially applicable to pain appraisal in youth with IBD and their parents. When health care providers communicate about pain, they should consider how symptom uncertainty may be influenced by threat, fear/worry, and biased attending. Further studies are needed to develop and test psychosocial interventions to reduce fear and threat of pain in youth with IBD in partnership with families and providers.

Gut-innervating nociceptors regulate the intestinal microbiota to promote tissue protection

Nociceptive pain is a hallmark of many chronic inflammatory conditions including inflammatory bowel diseases (IBDs); however, whether pain-sensing neurons influence intestinal inflammation remains poorly defined. Employing chemogenetic silencing, adenoviral-mediated colon-specific silencing, and pharmacological ablation of TRPV1+ nociceptors, we observed more severe inflammation and defective tissue-protective reparative processes in a murine model of intestinal damage and inflammation. Disrupted nociception led to significant alterations in the intestinal microbiota and a transmissible dysbiosis, while mono-colonization of germ-free mice with Gram+Clostridium spp. promoted intestinal tissue protection through a nociceptor-dependent pathway. Mechanistically, disruption of nociception resulted in decreased levels of substance P, and therapeutic delivery of substance P promoted tissue-protective effects exerted by TRPV1+ nociceptors in a microbiota-dependent manner. Finally, dysregulated nociceptor gene expression was observed in intestinal biopsies from IBD patients. Collectively, these findings indicate an evolutionarily conserved functional link between nociception, the intestinal microbiota, and the restoration of intestinal homeostasis.

Nociceptor neurons direct goblet cells via a CGRP-RAMP1 axis to drive mucus production and gut barrier protection

Neuroepithelial crosstalk is critical for gut physiology. However, the mechanisms by which sensory neurons communicate with epithelial cells to mediate gut barrier protection at homeostasis and during inflammation are not well understood. Here, we find that Nav1.8+CGRP+ nociceptor neurons are juxtaposed with and signal to intestinal goblet cells to drive mucus secretion and gut protection. Nociceptor ablation led to decreased mucus thickness and dysbiosis, while chemogenetic nociceptor activation or capsaicin treatment induced mucus growth. Mouse and human goblet cells expressed Ramp1, receptor for the neuropeptide CGRP. Nociceptors signal via the CGRP-Ramp1 pathway to induce rapid goblet cell emptying and mucus secretion. Notably, commensal microbes activated nociceptors to control homeostatic CGRP release. In the absence of nociceptors or epithelial Ramp1, mice showed increased epithelial stress and susceptibility to colitis. Conversely, CGRP administration protected nociceptor-ablated mice against colitis. Our findings demonstrate a neuron-goblet cell axis that orchestrates gut mucosal barrier protection.

Electrolyzed Hydrogen Water Alleviates Abdominal Pain through Suppression of Colonic Tissue Inflammation in a Rat Model of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the digestive tract and is typically accompanied by characteristic symptoms, such as abdominal pain, diarrhea, and bloody stool, severely deteriorating the quality of the patient's life. Electrolyzed hydrogen water (EHW) has been shown to alleviate inflammation in several diseases, such as renal disease and polymyositis/dermatomyositis. To investigate whether and how daily EHW consumption alleviates abdominal pain, the most common symptom of IBD, we examined the antioxidative and anti-inflammatory effects of EHW in an IBD rat model, wherein colonic inflammation was induced by colorectal administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS). We found that EHW significantly alleviated TNBS-induced abdominal pain and tissue inflammation. Moreover, the production of proinflammatory cytokines in inflamed colon tissue was also decreased significantly. Meanwhile, the overproduction of reactive oxygen species (ROS), which is intricately involved in intestinal inflammation, was significantly suppressed by EHW. Additionally, expression of S100A9, an inflammatory biomarker of IBD, was significantly suppressed by EHW. These results suggest that the EHW prevented the overproduction of ROS due to its powerful free-radical scavenging ability and blocked the crosstalk between oxidative stress and inflammation, thereby suppressing colonic inflammation and alleviating abdominal pain.

Involvement of Intestinal Enteroendocrine Cells in Neurological and Psychiatric Disorders

Neurological and psychiatric patients have increased dramatically in number in the past few decades. However, effective treatments for these diseases and disorders are limited due to heterogeneous and unclear pathogenic mechanisms. Therefore, further exploration of the biological aspects of the disease, and the identification of novel targets to develop alternative treatment strategies, is urgently required. Systems-level investigations have indicated the potential involvement of the brain–gut axis and intestinal microbiota in the pathogenesis and regulation of neurological and psychiatric disorders. While intestinal microbiota is crucial for maintaining host physiology, some important sensory and regulatory cells in the host should not be overlooked. Intestinal epithelial enteroendocrine cells (EECs) residing in the epithelium throughout intestine are the key regulators orchestrating the communication along the brain-gut-microbiota axis. On one hand, EECs sense changes in luminal microorganisms via microbial metabolites; on the other hand, they communicate with host body systems via neuroendocrine molecules. Therefore, EECs are believed to play important roles in neurological and psychiatric disorders. This review highlights the involvement of EECs and subtype cells, via secretion of endocrine molecules, in the development and regulation of neurological and psychiatric disorders, including Parkinson’s disease (PD), schizophrenia, visceral pain, neuropathic pain, and depression. Moreover, the current paper summarizes the potential mechanism of EECs in contributing to disease pathogenesis. Examination of these mechanisms may inspire and lead to the development of new aspects of treatment strategies for neurological and psychiatric disorders in the future.

The Role of Brain-Derived Neurotrophic Factor in Immune-Related Diseases: A Narrative Review

Brain-derived neurotrophic factor (BDNF) is a neurotrophin regulating synaptic plasticity, neuronal excitability, and nociception. It seems to be one of the key molecules in interactions between the central nervous system and immune-related diseases, i.e., diseases with an inflammatory background of unknown etiology, such as inflammatory bowel diseases or rheumatoid arthritis. Studies show that BDNF levels might change in the tissues and serum of patients during the course of these conditions, e.g., affecting cell survival and modulating pain severity and signaling pathways involving different neurotransmitters. Immune-related conditions often feature psychiatric comorbidities, such as sleep disorders (e.g., insomnia) and symptoms of depression/anxiety; BDNF may be related as well to them as it seems to exert an influence on sleep structure; studies also show that patients with psychiatric disorders have decreased BDNF levels, which increase after treatment. BDNF also has a vital role in nociception, particularly in chronic pain, hyperalgesia, and allodynia, participating in the formation of central hypersensitization. In this review, we summarize the current knowledge on BDNF's function in immune-related diseases, sleep, and pain. We also discuss how BDNF is affected by treatment and what consequences these changes might have beyond the nervous system.

Health-Related Quality of Life in Pediatric Inflammatory Bowel Disease Patients: A Narrative Review

Inflammatory bowel disease (IBD) is a chronic autoimmune condition that can have a wide range of symptoms among pediatric patients. Although clinical symptoms like hematochezia, diarrhea, and abdominal pain are commonly addressed, health-related quality of life (HRQOL) is often overlooked in patients with IBD and pediatric patients with chronic disease in general. Examining HRQOL can help improve patient outcomes, but it has been studied sparingly. In this review, we aim to compare HRQOL between pediatric patients suffering from IBD and healthy children, as well as those suffering from other illnesses. We searched through peer-reviewed primary literature related to IBD and HRQOL and selected 10 articles from the PubMed database to be reviewed. Our inclusion criteria included articles published after the year 2000 in English, primary studies, and those that corresponded to the aim of this review. Case reports and secondary and tertiary articles were excluded from our review. We found that patients with IBD reported worse HRQOL in terms of overall health and in various subdomains, including physical health and fatigue, compared to their healthy counterparts. However, children with IBD demonstrated a comparable HRQOL with children suffering from functional abdominal pain (FAP) and obesity. Additionally, children with IBD displayed a greater HRQOL than pediatric patients with gastroesophageal reflux disease (GERD) and chronic constipation. In addressing the aim of this review, we found that children with IBD had a lower HRQOL when compared to healthy children, but a comparable or greater HRQOL than other sick children. Some factors associated with a reduced HRQOL include disease activity, age, fatigue, gender, psychological variables, and associated symptoms. Going forward, HRQOL should be considered by practitioners when caring for pediatric IBD patients in a clinical setting as it can help improve patient care. More studies need to be conducted to further explore HRQOL in pediatric patients. This can help implement early psychosocial interventions in children to reduce the disease burden.

A Missing Piece of the Puzzle: Patient and Provider Perspectives on Pain Management Needs and Opioid Prescribing in Inflammatory Bowel Disease Care

Background

Recent data have shown high rates of opioid misuse among inflammatory bowel disease (IBD) patients. We conducted a qualitative study to explore IBD patient and provider perceptions and experiences with pain management and opioid prescribing.

Methods

We conducted a focus group with IBD patients and semistructured interviews with IBD-focused physicians and nurses. We used an inductive approach for analysis and the constant comparison method to develop and refine codes and identify prominent themes. We analyzed interview and focus group data concurrently to triangulate themes.

Results

Nine patients and 10 providers participated. We grouped themes into 3 categories: (1) current practices to manage pain; (2) perceived pain management challenges; and (3) suggestions to optimize pain management. In the first category (current practices), both patients and providers reported building long-term patient-provider relationships and the importance of exploring nonpharmacologic pain management strategies. Patients reported proactively trying remedies infrequently recommended by IBD providers. In the second category (pain management challenges), patients and providers reported concerns about opioid use and having limited options to treat pain safely. Patients discussed chronic pain and having few solutions to manage it. In the third category, providers shared suggestions for improvement such as increasing use of nonpharmacologic pain management strategies and enhancing care coordination.

Conclusions

Despite some common themes between the 2 groups, we identified some pain management needs (eg, addressing chronic pain) that matter to patients but were seldom discussed by IBD providers. Addressing these areas of potential disconnect is essential to optimize pain management safety in IBD care.

Pain Characteristics in Patients with Inflammatory Bowel Disease: A Monocentric Cross-Sectional Study

BACKGROUND AND AIMS

The abdominal pain common in inflammatory bowel disease [IBD] patients is traditionally associated with inflammation but may persist during clinical remission. Central sensitization [CS] has not previously been explored in these patients. This study aimed to determine the epidemiology of pain in IBD patients and to specify pain characteristics with particular attention to CS.

METHODS

This cross-sectional study included 200 patients; 67% had Crohn's disease [CD]. Pain was assessed using the McGill questionnaire, using the Douleur Neuropathique 4 [DN4] questionnaire and by clinical examination. Its impacts on quality of life, depression and anxiety were also assessed.

RESULTS

Three-quarters of IBD patients complained of pain, including intermittent pain attacks, 62% reported abdominal pain and 17.5% had CS. The prevalence of pain [83.6% vs 59.1%; p < 0.001] and abdominal pain [68.7% vs 48.5%; p = 0.006] was higher in CD patients than in ulcerative colitis [UC] patients. Multivariate analysis confirmed that age [p = 0.02], sex [female] [p = 0.004] and CD [p = 0.005] were independent risk factors for pain. Pain intensity was greater in the case of CS (6 [5-3] vs 3 [1.5-5], p < 0.003) which significantly impaired quality of life [p < 0.003] compared with pain without CS.

CONCLUSIONS

The prevalence of pain was high in IBD patients [≈75%] and higher in CD patients. Significant impacts on quality of life were confirmed. More than 25% of patients with abdominal pain described CS as responsible for more severe pain and worsened quality of life.

TRIAL REGISTRATION REF

NCT04488146.

Dental Pulp-Derived Stem Cells Reduce Inflammation, Accelerate Wound Healing and Mediate M2 Polarization of Myeloid Cells

This work aimed to validate the potential use of dental pulp-derived stem cells (DPSCs) for the treatment of inflammation by defining their mechanisms of action. We planned to investigate whether priming of DPSC with proinflammatory molecules had any impact on their behavior and function. In the first step of our validation in vitro, we showed that priming of DPSCs with the bioactive agents LPS, TNF-α, or IFN-γ altered DPSCs’ immunologic properties by increasing their expression levels of IL-10, HGF, IDO, and IL-4 and by decreasing their mitochondrial functions. Moreover, DPSCs induced accelerated wound healing irrespective of priming, as determined by using a gut epithelial cell line in a scratch wound assay. Wound healing of gut epithelial cells was mediated by regulating the expressions of AKT, NF-κB, and ERK1/2 proteins compared to the control epithelial cells. In addition, primed DPSCs altered monocyte polarization toward an immuno-suppressive phenotype (M2), where monocytes expressed higher levels of IL-4R, IL-6, Arg1, and YM-1 compared to monocytes cultured with control DPSCs. In silico analysis revealed that this was accomplished in part by the interaction between kynurenine and PPARγ, which regulated the expression of M2 differentiation-related genes. Collectively, these data provided evidence that the DPSCs reduced inflammation, induced M2 polarization of myeloid cells, and healed damaged gut epithelial cells through inactivation of inflammation and modulating constitutively active signaling pathways.

Inflammatory Bowel Disease and Pain Interference: A Conceptual Model for the Role of Insomnia, Fatigue, and Pain Catastrophizing

Background

People with inflammatory bowel disease (IBD) commonly experience pain influenced by complex interactions among factors, including disease activity, sleep, psychopathology, and changes in pain processing pathways. Treatments for pain in IBD are limited, highlighting the need for research that explores modifiable factors linked to pain. The aim of this study was to investigate relationships among multiple patient factors and to construct a conceptual model for pain interference in IBD.

Methods

A cross-sectional survey of adults with IBD. Study domains included demographic, comorbidity, psychological, IBD, insomnia, fatigue, and pain features. Structural equation modeling (SEM) was used to examine relationships and interactions among active IBD, insomnia, fatigue, pain experiences (severity, catastrophizing, and interference), and additional patient factors (demographics and psychological).

Results

One hundred and seventy-four participants, aged 18-85 years, reported the presence of pain. Combining the questionnaire data using SEM resulted in a final model with an excellent fit (χ ²(8) = 9.579, P = .297, χ ²/N = 1.197, CFIN = 0.997, TLI = 0.987, RMSEA = 0.034). The presence of anxiety and depression was the additional patient factors to be retained in the path analysis. SEM results indicated that greater pain interference was directly influenced by greater fatigue, worse pain catastrophizing, and worse pain severity. Pain interference was indirectly impacted by IBD activity, worse insomnia, and the presence of depression and anxiety.

Conclusions

The proposed conceptual model highlights the role of multiple potentially modifiable factors, including insomnia, pain catastrophizing, and fatigue, contributing to worse pain interference in people with IBD.

Abdominal Pain in Inflammatory Bowel Diseases: A Clinical Challenge

Up to 60% of inflammatory bowel disease (IBD) patients experience abdominal pain in their lifetime regardless of disease activity. Pain negatively affects different areas of daily life and particularly impacts the quality of life of IBD patients. This review provides a comprehensive overview of the multifactorial etiology implicated in the chronic abdominal pain of IBD patients including peripheral sensitization by inflammation, coexistent irritable bowel syndrome, visceral hypersensitivity, alteration of the brain–gut axis, and the multiple factors contributing to pain persistence. Despite the optimal management of intestinal inflammation, chronic abdominal pain can persist, and pharmacological and non-pharmacological approaches are necessary. Integrating psychological support in care models in IBD could decrease disease burden and health care costs. Consequently, a multidisciplinary approach similar to that used for other chronic pain conditions should be recommended.

Peripheral GABAA receptor signaling contributes to visceral hypersensitivity in a mouse model of colitis

ABSTRACT

Pain is a common and debilitating symptom of inflammatory bowel disease (IBD). Based on evidence that peripheral GABAA receptor (GAR) inhibition plays an important role in establishing colonic afferent excitability and nociceptive threshold, we hypothesized that the increase in pain associated with IBD is due to, at least in part, a decrease in peripheral GAR-mediated inhibition. Acute colitis was induced with 5 days of dextran sodium sulfate (DSS, 3%) in the drinking water. Visceral sensitivity was assessed with the visceromotor response (VMR) evoked with balloon distention of the colon in control and DSS-treated mice before and after intracolonic administration of GAR agonist muscimol, the high-affinity GAR preferring agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine-3-ol (THIP), the GAR positive allosteric modulator diazepam, or the GAR antagonists gabazine and bicuculline. Low concentrations of muscimol or THIP increased the VMR in DSS-treated mice but not in control mice. However, high concentrations of muscimol decreased the VMR in both control and DSS-treated mice. Diazepam decreased the VMR in both DSS-treated and control mice. By contrast, at a concentration of gabazine that blocks only low-affinity GAR, there was no effect on the VMR in either DSS-treated or control mice, but at concentrations of the antagonist that block low-affinity and high-affinity GAR, the VMR was increased in control mice and decreased in DSS-treated mice. Furthermore, bicuculline increased the VMR in control mice but decreased it in DSS-treated mice. These data suggest that activating of low-affinity GAR or blocking high-affinity GAR may be effective therapeutic strategies for the management of pain in IBD.

Symptoms associated with healthcare resource utilization in the setting of inflammatory bowel disease

Several symptoms have been connected to increased healthcare resource utilization (HRU) in the context of inflammatory bowel disease (IBD), including both Crohn's disease (CD) and ulcerative colitis (UC). This study was designed to investigate the prevalence of IBD-associated symptoms and to determine whether any are independently associated with HRU. We undertook a retrospective analysis of data related to consecutive IBD patient encounters from a tertiary care referral center between 1/1/2015 and 8/31/2019. Demographics, clinical activity, endoscopic severity, IBD-related symptom scores, anxiety and depression scores, and other key clinical data were abstracted. Four hundred sixty-seven IBD patients [247f.: 220 m; 315 CD, 142 UC and 11 indeterminate colitis] were included in this study. The most common symptoms were fatigue (83.6%), fecal urgency (68.2%) and abdominal pain (63.5%). Fatigue, abdominal pain, anxiety or depression, corticosteroids, and opioids were each positively associated with HRU, while NSAID and mesalamine use were inversely associated on bivariate analysis. The only factor that demonstrated a statistically significant association with HRU in the whole cohort on multivariable analysis was abdominal pain. Abdominal pain is independently associated with HRU and should be specifically screened for in IBD patients to identify individuals at risk of undergoing expensive interventions. This study also reinforces the importance of optimizing diagnostic and therapeutic management of abdominal pain in IBD.

Mesenchymal stem cell treatment for enteric neuropathy in the Winnie mouse model of spontaneous chronic colitis

Inflammatory bowel disease (IBD) is a chronic gut inflammation with periods of acute flares and remission. Beneficial effects of a single dose of mesenchymal stem cell (MSC)-based treatment have been demonstrated in acute models of colitis. No studies investigated therapeutic effects of MSCs for the attenuation of enteric neuropathy in a chronic model of colitis. The short and long-term effects of MSC treatment in modulating inflammation and damage to the enteric nervous system (ENS) were studied in the Winnie mouse model of spontaneous chronic colitis highly representative of human IBD. Winnie mice received a single dose of either 1 × 10⁶ human bone marrow-derived MSCs or 100µL PBS by intracolonic enema. C57BL/6 mice received 100µL PBS. Colon tissues were collected at 3 and 60 days post MSC administration to evaluate the short-term and long-term effects of MSCs on inflammation and enteric neuropathy by histological and immunohistochemical analyses. In a separate set of experiments, multiple treatments with 4 × 10⁶ and 2 × 10⁶ MSCs were performed and tissue collected at 3 days post treatment. Chronic intestinal inflammation in Winnie mice was associated with persistent diarrhea, perianal bleeding, morphological changes, and immune cell infiltration in the colon. Significant changes to the ENS, including impairment of cholinergic, noradrenergic and sensory innervation, and myenteric neuronal loss were prominent in Winnie mice. Treatment with a single dose of bone marrow-derived MSCs was ineffective in attenuating chronic inflammation and enteric neuropathy in Winnie.

Somatosensory assessments in patients with inflammatory bowel disease: a cross-sectional study examining pain processing pathways and the role of multiple patient factors

BACKGROUND

Pain affects the majority of patients with inflammatory bowel disease (IBD), where pain experiences may be influenced by multiple patient factors and changes within central pain processing pathways, termed central sensitization. The current study aimed to investigate pain processing pathways in patients with IBD through somatosensory testing and associations with multiple patient factors.

METHODS

A cross-sectional study of adults with IBD. Assessments included: somatosensory tests [i.e. pressure pain thresholds (PPT), temporal summation (TS), conditioned pain modulation (CPM)], and patient factors (i.e. demographics, comorbidity, sleep quality, psychological, pain severity and interference, and IBD features). Multiple regression analyses explored associations between somatosensory tests and multiple patient factors.

RESULTS

Decreased CPM in participants (N = 51) was associated with worse abdominal pain severity and use of biologic therapies (R2 = 0.30, F(5,44) = 5.18, P = 0.001). Increased TS was associated with biologic use (R2 = 0.11, F(1,49) = 6.13, P = 0.017). Decreased PPT at the low back (R2 = 0.29, F(2,48) = 11.21, P < 0.001) and Tibialis anterior (R2 = 0.41, F(2,48) = 18.26, P < 0.001) were associated with female sex and the absence of a stoma.

CONCLUSION

Study results demonstrated associations between multiple patient factors and somatosensory tests in patients with IBD. The absence of a stoma and female sex was associated with greater sensitivity to pressure in two remote body regions, suggestive of widespread hyperalgesia. Worse abdominal pain severity and biologic use were associated with decreased pain inhibition, and biologic use was also associated with increased pain facilitation. These findings suggest the presence of altered pain processing and mechanisms of central sensitization in patients with IBD.

Effects of probiotic supplementation on abdominal pain severity in pediatric patients with irritable bowel syndrome: a systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Probiotic supplementation has been used to alleviate abdominal pain in children and adolescents with irritable bowel syndrome (IBS), but the evidence is not compelling. Thus, a systematic review and meta-analysis of randomized clinical trials (RCTs) were performed to investigate the effects of probiotic supplementation on abdominal pain in pediatric patients with IBS.

METHODS

PubMed/MEDLINE, Web of Science, Scopus, Cochrane Library, and Embase were the available databases searched to find relevant randomized clinical trials up to April 2021. The effect size was expressed as weighted mean difference (WMD) and 95% confidence interval (CI).

RESULTS

Seven RCTs with 441 participants were included, from which the meta-analysis demonstrated that probiotic supplementation has a significant effect on reducing abdominal pain in pediatric patients with IBS (WMD = - 2.36; 95% CI - 4.12 to - 0.60; P = 0.009). Although our study involved children and adolescents (≤ 18 years), the effects of probiotic supplementation seem to be more potent in patients under 10 years old (WMD = - 2.55; 95% CI - 2.84 to - 2.27) compared to patients aged 10-18 years (WMD = - 1.70; 95% CI - 2.18 to - 1.22). The length of supplementation longer than four weeks was more effective (WMD = - 2.43; 95% CI - 2.76 to - 2.09).

CONCLUSION

Probiotic supplementation can reduce abdominal pain in pediatric patients with IBS.

TRPA1 Role in Inflammatory Disorders: What Is Known So Far?

The transient receptor potential ankyrin 1 (TRPA1), a member of the TRP superfamily of channels, is primarily localized in a subpopulation of primary sensory neurons of the trigeminal, vagal, and dorsal root ganglia, where its activation mediates neurogenic inflammatory responses. TRPA1 expression in resident tissue cells, inflammatory, and immune cells, through the indirect modulation of a large series of intracellular pathways, orchestrates a range of cellular processes, such as cytokine production, cell differentiation, and cytotoxicity. Therefore, the TRPA1 pathway has been proposed as a protective mechanism to detect and respond to harmful agents in various pathological conditions, including several inflammatory diseases. Specific attention has been paid to TRPA1 contribution to the transition of inflammation and immune responses from an early defensive response to a chronic pathological condition. In this view, TRPA1 antagonists may be regarded as beneficial tools for the treatment of inflammatory conditions.

Opioid-Induced Pronociceptive Signaling in the Gastrointestinal Tract Is Mediated by Delta-Opioid Receptor Signaling

Opioid tolerance (OT) leads to dose escalation and serious side effects, including opioid-induced hyperalgesia (OIH). We sought to better understand the mechanisms underlying this event in the gastrointestinal tract. Chronic in vivo administration of morphine by intraperitoneal injection in male C57BL/6 mice evoked tolerance and evidence of OIH in an assay of colonic afferent nerve mechanosensitivity; this was inhibited by the δ-opioid receptor (DOPr) antagonist naltrindole when intraperitoneally injected in previous morphine administration. Patch-clamp studies of DRG neurons following overnight incubation with high concentrations of morphine, the µ-opioid receptors (MOPr) agonist [D-Ala2, N-Me-Phe4, Gly5-ol]-Enkephalin (DAMGO) or the DOPr agonist [D-Ala2, D-Leu5]-Enkephalin evoked hyperexcitability. The pronociceptive actions of these opioids were blocked by the DOPr antagonist SDM25N but not the MOPr antagonist D-Pen-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 The hyperexcitability induced by DAMGO was reversed after a 1 h washout, but reapplication of low concentrations of DAMGO or [D-Ala2, D-Leu5]-Enkephalin restored the hyperexcitability, an effect mediated by protein kinase C. DOPr-dependent DRG neuron hyperexcitability was blocked by the endocytosis inhibitor Pitstop 2, and the weakly internalizing DOPr agonist ARM390 did not cause hyperexcitability. Bioluminescence resonance energy transfer studies in HEK cells showed no evidence of switching of G-protein signaling from Gi to a Gs pathway in response to either high concentrations or overnight incubation of opioids. Thus, chronic high-dose opioid exposure leads to opioid tolerance and features of OIH in the colon. This action is mediated by DOPr signaling and is dependent on receptor endocytosis and downstream protein kinase C signaling.SIGNIFICANCE STATEMENT Opioids are effective in the treatment of abdominal pain, but escalating doses can lead to opioid tolerance and potentially opioid-induced hyperalgesia. We found that δ-opioid receptor (DOPr) plays a central role in the development of opioid tolerance and opioid-induced hyperalgesia in colonic afferent nociceptors following prolonged exposure to high concentrations of MOPr or DOPr agonists. Furthermore, the role of DOPr was dependent on OPr internalization and activation of a protein kinase C signaling pathway. Thus, targeting DOPr or key components of the downstream signaling pathway could mitigate adverse side effects by opioids.

Preoperative Opioid Dose and Surgical Outcomes in Colorectal Surgery

BACKGROUND

The worsening opioid epidemic has led to an increased number of surgical patients with chronic preoperative opioid use. However, the impact of opioids on perioperative outcomes has yet to be fully elucidated. The purpose of this study was to assess the association between preoperative opioid dose and surgical outcomes among colectomy patients.

METHODS

Adult colectomy patients in the IBM MarketScan database (2010-2017) were stratified based on preoperative opioid dose, calculated as the average opioid dose in morphine milligram equivalents (MME) in the 90 days prior to surgery: 0 MME, 1 to 49 MME, and 50 or more MME. The association between preoperative opioid dose and anastomotic leak, the primary outcome of interest, as well as other postoperative complications, was assessed using multivariable regression.

RESULTS

Among 45,515 adult colectomy patients, 71.4% did not use opioids (0 MME), 27.4% had an opioid dose between 1 and 49 MME, and 1.2% had an opioid dose at or above 50 MME. Patients with preoperative opioid use exhibited a higher incidence of anastomotic leak (0 MME: 4.8%, 1-49 MME: 5.5%, ≥50 MME: 8.3%; p trend = 0.001). Multivariable analysis demonstrated a dose-response relationship between preoperative opioids and surgical outcomes, as the odds of anastomotic leak worsened with increasing opioid dose (1-49 MME: OR 1.19, 95% CI 1.08-1.31, p < 0.001; ≥50 MME: OR 1.64, 95% CI 1.20-2.24, p = 0.002). Similar dose-response relationships were seen after risk-adjustment for lung complications, pneumonia, delirium, and 30-day readmission (p < 0.05 for all).

CONCLUSIONS

Providers should exercise caution when prescribing opioids preoperatively, as increasing doses of preoperative opioids were associated with worse surgical outcomes and higher 30-day readmission among adult colectomy patients.

The Relationship Between Opioid Use and Healthcare Utilization in Patients With Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Pain is commonly experienced by patients with inflammatory bowel disease (IBD). Unfortunately, pain management is a challenge in IBD care, as currently available analgesics are associated with adverse events. Our understanding of the impact of opioid use on healthcare utilization among IBD patients remains limited.

METHODS

A systematic search was completed using PubMed, Embase, the Cochrane Library, and Scopus through May of 2020. The exposure of interest was any opioid medication prescribed by a healthcare provider. Outcomes included readmissions rate, hospitalization, hospital length of stay, healthcare costs, emergency department visits, outpatient visits, IBD-related surgeries, and IBD-related medication utilization. Meta-analysis was conducted on study outcomes reported in at least 4 studies using random-effects models to estimate pooled relative risk (RR) and 95% confidence interval (CI).

RESULTS

We identified 1969 articles, of which 30 met inclusion criteria. Meta-analysis showed an association between opioid use and longer length of stay (mean difference, 2.25 days; 95% CI, 1.29-3.22), higher likelihood of prior IBD-related surgery (RR, 1.72; 95% CI, 1.32-2.25), and higher rates of biologic use (RR, 1.38; 95% CI, 1.13-1.68) but no difference in 30-day readmissions (RR, 1.17; 95% CI, 0.86-1.61), immunomodulator use (RR, 1.13; 95% CI, 0.89-1.44), or corticosteroid use (RR, 1.36; 95% CI, 0.88-2.10) in patients with IBD. On systematic review, opioid use was associated with increased hospitalizations, healthcare costs, emergency department visits, outpatient visits, and polypharmacy.

DISCUSSION

Opioids use among patients with IBD is associated with increased healthcare utilization. Nonopioid alternatives are needed to reduce burden on the healthcare system and improve patient outcomes.

Lycium barbarum Polysaccharides and Capsaicin Inhibit Oxidative Stress, Inflammatory Responses, and Pain Signaling in Rats with Dextran Sulfate Sodium-Induced Colitis

Ulcerative colitis (UC) is an inflammatory disease with chronic relapsing symptoms. This study investigated the effects of Lycium barbarum polysaccharides (LBP) and capsaicin (CAP) in dextran sulfate sodium (DSS)-induced UC rats. Rats were divided into normal, DSS-induced UC, and UC treated with 100 mg LBP/kg bw, 12 mg CAP/kg bw, or 50 mg LBP/kg bw and 6 mg CAP/kg bw. Rats were fed LBP or CAP orally by gavage for 4 weeks, and UC model was established by feeding 5% DSS in drinking water for 6 days during week 3. Oral CAP and mixture significantly reduced disease activity index. Oral LBP significantly decreased serum malondialdehyde, interleukin (IL)-6, colonic tumor necrosis factor (TNF)-α levels, and protein expression of transient receptor potential cation channel V1 (TRPV1) and transient receptor potential ankyrin 1 (TRPA1), but increased serum catalase activity. Oral CAP significantly suppressed serum IL-6, colonic TRPV1 and TRPA1 protein expression, but elevated IL-10 levels, serum superoxide dismutase and catalase activities. The mixture of LBP and CAP significantly reduced serum IL-6, colonic TNF-α and TRPA1 protein. In conclusion, administration of LBP and/or CAP attenuate DSS-induced UC symptoms through inhibiting oxidative stress, proinflammatory cytokines, and protein expression of TRPV1 and TRPA1.