Risk of cardiovascular disease in inflammatory bowel disease

Mortality in patients with Inflammatory Bowel Disease: Results from 30 years of follow-up in a Norwegian inception cohort (the IBSEN study)

BACKGROUND AND AIMS

Patients with longstanding inflammatory bowel disease (IBD) may be at an increased risk of death compared to the general population, especially elderly patients. The Inflammatory Bowel South-Eastern Norway (IBSEN) study has previously detected a small but not statistically significant increase in mortality, 20 years after diagnosis. The aim of this study was to evaluate the overall and cause-specific mortality at 30 years of follow-up.

METHODS

The IBSEN cohort included 519 incident patients with ulcerative colitis (UC) and 237 patients with Crohn's disease (CD) between 1990 and 1993, each matched with five controls. Death certificate data were obtained from the Norwegian Cause of Death Registry. The underlying causes of death were categorised into five groups: all cancers, gastrointestinal cancers, cardiovascular diseases, infections, and all other causes. Hazard ratios (HR) were modelled using Cox regression.

RESULTS

There was no statistically significant difference in the overall mortality rates. However, in patients with CD, male sex (HR = 1.65 [1.04-2.62]), onset after 40 years of age (HR = 1.72 [95% CI: 1.19-2.48]), colonic disease (HR = 1.57 [1.05-2.35]), and penetrating behavior (HR = 3.3 [1.41-7.76]) were clinical factors associated with an increased mortality. IBD patients were at a higher risk of death due to cardiovascular disease; HR = 1.51 [1.10-2.08] for UC and 2.04 [1.11-3.77] for CD. When taking into account both the underlying and the immediate cause of death, infection was more frequent in patients with IBD.

CONCLUSIONS

Overall, all-cause mortality rates were similar between patients with IBD and controls. However, clinicians should remain alert to cardiovascular diseases and infections, particularly in specific subgroups of CD patients.

Activation of Platelet NLRP3 Inflammasome in Crohn's Disease

Patients with Crohn’s disease (CD) are inclined to have platelet hyperactivity and an increased risk of intestinal micro-thrombosis. However, the mechanisms underlying platelet hyperactivity in CD are not well understood. We investigated the assembly of platelet NLRP3 inflammasome in patients with active CD and its correlation with platelet hyperactivity. In this study, Real-time PCR and western blotting analyses uncovered that ASC, NLRP3, and active caspase-1 were significantly upregulated in platelets from patients with active CD compared with healthy subjects. As revealed by flow cytometry (FCM) and ELISA analyses, the levels of interleukin-1β in both serum and isolated platelets were elevated in patients with active CD. Co-immunoprecipitation and immunofluorescence experiments revealed an increased assembly of NLRP3 inflammasome in platelets from patients with active CD. In addition, higher levels of intracellular reactive oxygen species (ROS) were observed in these platelets by FCM. Furthermore, elevated levels of platelet P-selectin exposure and fibrinogen binding were demonstrated in patients with active CD by FCM. They were positively correlated with the protein levels of NLRP3 inflammasome components. Collectively, our results indicate that the ROS-NLRP3 inflammasome-interleukin-1β axis may contribute to platelet hyperactivity in active CD.

Cannabinoids and Inflammations of the Gut-Lung-Skin Barrier

Recent studies have identified great similarities and interferences between the epithelial layers of the digestive tract, the airways and the cutaneous layer. The relationship between these structures seems to implicate signaling pathways, cellular components and metabolic features, and has led to the definition of a gut-lung-skin barrier. Inflammation seems to involve common features in these tissues; therefore, analyzing the similarities and differences in the modulation of its biomarkers can yield significant data promoting a better understanding of the particularities of specific signaling pathways and cellular effects. Cannabinoids are well known for a wide array of beneficial effects, including anti-inflammatory properties. This paper aims to explore the effects of natural and synthetic cannabinoids, including the components of the endocannabinoid system, in relation to the inflammation of the gut-lung-skin barrier epithelia. Recent advancements in the use of cannabinoids as anti-inflammatory substances in various disorders of the gut, lungs and skin are detailed. Some studies have reported mixed or controversial results, and these have also been addressed in our paper.

Lipopolysaccharides modulate intestinal epithelial permeability and inflammation in a species-specific manner

Patients presenting with Inflammatory bowel disease have been shown to exhibit an altered microbiome in both Crohn's disease and Ulcerative colitis. This shift in the microbial content led us to question whether several of these microbes are important in inflammatory processes present in these diseases and more specifically whether lipopolysaccharides from the gram-negative cell wall differentially stimulates resident cells. We, therefore, investigated the possible contribution of five major species of gram-negative bacteria found to be altered in presence during disease progression and evaluate their pathogenicity through LPS. We demonstrated that LPS from these different species had individual capacities to induce NF-κB and pro-inflammatory IL-8 production from HEK-TLR4 cells in a TLR4 dependent manner. Additional work using human intestinal colonic epithelial cell monolayers (Caco-2) demonstrated that the cells responded to the serotype specific LPS in a distinct manner, inducing many inflammatory mediators such as TNF-α and IL-10 in significantly altered proportions. Furthermore, the permeability of Caco-2 monolayers, as a test for their ability to alter intestinal permeability, was also differentially altered by the serotype specific LPS modulating trans-epithelial electrical resistance, small molecule movement, and tight junction integrity. Our results suggest that specific species of bacteria may be potentiating the pathogenesis of IBD and chronic inflammatory diseases through their serotype specific LPS responses.

Serum Catestatin Levels and Arterial Stiffness Parameters Are Increased in Patients with Inflammatory Bowel Disease

Catestatin (CST) is an important peptide in the pathophysiology of chronic inflammatory disorders. However, clinical studies on inflammatory bowel disease (IBD) patients are lacking. Our goal was to investigate CST concentrations in IBD patients compared to healthy subjects. Additionally, we aimed to determine arterial stiffness parameters in relation to CST. This cross-sectional study compared 80 IBD patients (45 Crohn's disease (CD) and 35 ulcerative colitis (UC) patients) with 75 control subjects. Serum CST levels were significantly higher in the IBD group compared to control subjects (11.29 ± 9.14 vs. 7.13 ± 6.08 ng/mL, p = 0.001) and in the UC group compared to CD patients (13.50 ± 9.58 vs. 9.03 ± 6.92 ng/mL, p = 0.021), irrespective of age and BMI. IBD patients exhibited significantly higher values of heart rate adjusted central augmentation index (cAIx-75) (14.88 ± 10.59 vs. 6.87 ± 9.50 %, p < 0.001) and pulse wave velocity (PWV) (8.06 ± 3.23 vs. 6.42 ± 1.47 m/s, p < 0.001) compared to control group. Furthermore, PWV was the only significant independent correlate of CST (B = 1.20, t = 4.15, p < 0.001), while CST, PWV, cAIx-75, high-sensitivity C-reactive protein and BMI were significant predictors of positive IBD status (1.089 (1.022-1.161), 1.515 (1.166-1.968), 1.060 (1.024-1.097), 1.458 (1.116-1.906), 0.793 (0.683-0.920), respectively). Serum CST levels were significantly higher in IBD patients compared to controls and an independent positive correlation of CST with PWV existed. Therefore, it is possible that CST could have a role in the complex pathophysiology of IBD and its cardiovascular complications.

Overview of Link Between Inflammatory Bowel Disease and Cardiovascular Disease

Inflammation has been shown to play an increasingly important role in the pathogenesis of atherosclerosis and in precipitating thrombotic events. Inflammatory bowel disease (IBD) is a systemic inflammatory disorder with a wide range of extraintestinal manifestations including a clinically significant increase in the risk of venous thromboembolism compared to matched controls in several studies. The data for the association between IBD and ischemic heart disease are less clear; multiple population-based studies have shown both positive and negative associations between the 2 conditions. While the systemic inflammation should theoretically increase the risk for cardiovascular disease, inflammatory bowel also potentially provides a cardioprotective effect in several ways. Patients with IBD typically enter the healthcare system at an earlier age and experience a lower incidence of obesity, hypercholesterolemia, and hyperlipidemia. Given the complex interplay among the proatherogenic, prothrombogenic, and cardioprotective effects, IBD should be taken into consideration as a nontraditional risk factor for cardiovascular disease in specific subsets of patients.

Eicosapentaenoic Acid as a Potential Therapeutic Approach to Reduce Cardiovascular Risk in Patients with End-Stage Renal Disease on Hemodialysis: A Review

Background

Patients with end-stage renal disease on hemodialysis have excess cardiovascular disease (CVD) burden with substantially increased CV event rates compared with the general population.

Summary

Traditional interventions that, according to standard clinical guidelines, reduce CV risk such as antihypertensive therapy, diet, exercise, and statins are not similarly effective in the hemodialysis population. This raises the question of whether additional risk factors, such as enhanced inflammation and oxidative stress, may drive the increased CVD burden in hemodialysis patients. Eicosapentaenoic acid (EPA), an omega-3 polyunsaturated fatty acid, is incorporated into the atherosclerotic plaque as well as membrane phospholipid bilayers and produces beneficial effects on inflammatory and oxidative mechanisms involved in atherosclerotic plaque formation and progression. EPA levels and the ratio of EPA to the omega-6 polyunsaturated fatty acid arachidonic acid (AA) are reduced in hemodialysis patients. Serum EPA levels have been inversely correlated with proinflammatory cytokines, and the EPA/AA ratio has been inversely associated with CV events in hemodialysis cohorts. Three recent studies involving over 800 hemodialysis patients and follow-up of 2-3 years suggest that EPA therapy may improve clinical outcomes in this patient population as evidenced by significant reductions in cardiovascular mortality, all-cause mortality, and/or CV events.

Key Messages

Further studies with high-purity EPA are warranted in patients on hemodialysis, especially given the fact that other interventions including antihypertensives, diet, exercise, and statins have not provided meaningful benefit.

Development of Inflammatory Bowel Disease Is Linked to a Longitudinal Restructuring of the Gut Metagenome in Mice

The gut microbiome is linked to inflammatory bowel disease (IBD) severity and altered in late-stage disease. However, it is unclear how gut microbial communities change over the course of IBD development, especially in regard to function. To investigate microbiome-mediated disease mechanisms and discover early biomarkers of IBD, we conducted a longitudinal metagenomic investigation in an established mouse model of IBD, where damped transforming growth factor β (TGF-β) signaling in T cells leads to peripheral immune activation, weight loss, and severe colitis. IBD development is associated with abnormal gut microbiome temporal dynamics, including damped acquisition of functional diversity and significant differences in abundance trajectories for KEGG modules such as glycosaminoglycan degradation, cellular chemotaxis, and type III and IV secretion systems. Most differences between sick and control mice emerge when mice begin to lose weight and heightened T cell activation is detected in peripheral blood. However, levels of lipooligosaccharide transporter abundance diverge prior to immune activation, indicating that it could be a predisease indicator or microbiome-mediated disease mechanism. Taxonomic structure of the gut microbiome also significantly changes in association with IBD development, and the abundances of particular taxa, including several species of Bacteroides, correlate with immune activation. These discoveries were enabled by our use of generalized linear mixed-effects models to test for differences in longitudinal profiles between healthy and diseased mice while accounting for the distributions of taxon and gene counts in metagenomic data. These findings demonstrate that longitudinal metagenomics is useful for discovering the potential mechanisms through which the gut microbiome becomes altered in IBD. IMPORTANCE IBD patients harbor distinct microbial communities with functional capabilities different from those seen with healthy people. But is this cause or effect? Answering this question requires data on changes in gut microbial communities leading to disease onset. By performing weekly metagenomic sequencing and mixed-effects modeling on an established mouse model of IBD, we identified several functional pathways encoded by the gut microbiome that covary with host immune status. These pathways are novel early biomarkers that may either enable microbes to live inside an inflamed gut or contribute to immune activation in IBD mice. Future work will validate the potential roles of these microbial pathways in host-microbe interactions and human disease. This study was novel in its longitudinal design and focus on microbial pathways, which provided new mechanistic insights into the role of gut microbes in IBD development.

Targeting inflammation to reduce cardiovascular disease risk: a realistic clinical prospect?

Data from basic science experiments is overwhelmingly supportive of the causal role of immune-inflammatory response(s) at the core of atherosclerosis, and therefore, the theoretical potential to manipulate the inflammatory response to prevent cardiovascular events. However, extrapolation to humans requires care and we still lack definitive evidence to show that interfering in immune-inflammatory processes may safely lessen clinical atherosclerosis. In this review, we discuss key therapeutic targets in the treatment of vascular inflammation, placing basic research in a wider clinical perspective, as well as identifying outstanding questions.

LINKED ARTICLES

This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

Obesity Downregulates MicroRNA-126 Inducing Capillary Rarefaction in Skeletal Muscle: Effects of Aerobic Exercise Training

Background. We investigated the effects of exercise training (ET) on miR-126 levels and skeletal muscle angiogenesis in obese Zucker rats. Results. Zucker rats were randomly assigned to sedentary and swimming-trained groups: lean sedentary (LS) and trained (LTR); obese sedentary (OB) and trained (OBTR). The OB group displayed capillary rarefaction compared with the LS group. In contrast, ET increased the capillary/fiber ratio by 38% in the LTR group and normalized capillary rarefaction in the OBTR group. VEGF, PI3K, and eNOS levels were reduced in the skeletal muscle of the OB group. ET normalized VEGF, PI3K, and eNOS levels in OBTR, contributing to vascular network homeostasis. PI3KR2 inhibits PI3K, a key mediator of the VEGF signaling pathway. Obesity decreased miR-126 and increased PI3KR2 levels compared with the LS group. However, ET normalized miR-126 levels in the OBTR group versus the LS group and decreased expression of PI3KR2. Conclusion. Our findings show that obesity leads to skeletal muscle capillary rarefaction, which is regulated by decreased miR-126 levels and increased PI3KR2. Inversely, ET normalizes miR-126 levels and VEGF signaling and should be considered an important therapeutic strategy for vascular disorders.

Vedolizumab: toward a personalized therapy paradigm for people with ulcerative colitis

Ulcerative colitis (UC) is a chronic relapsing and remitting inflammatory bowel disease, with a characteristic leukocytic infiltration of the mucosa. Immunosuppression including anti-TNF-α therapy is a mainstay of treatment for many; however, systemic immunosuppression is not universally effective and is associated with potential side effects. The gut-tropic integrin α4β7, which is expressed on leukocytes, mediates migration from the circulation to the intestinal mucosa. Vedolizumab is a monoclonal antibody which blocks the egress of leukocytes via α4β7, preventing accumulation in the mucosa, and attenuating inflammation without systemic immunosuppression. Vedolizumab has been evaluated in UC in a phase III trial, demonstrating efficacy as both an induction and a maintenance agent. In this article, we review the clinical trial data and also explore the growing body of "real-world" effectiveness data, investigating response and remission rates of vedolizumab in clinical practice. In addition, we review the increasing volume of data supporting the reassuring safety profile associated with vedolizumab.

Associations of Bowel Movement Frequency with Risk of Cardiovascular Disease and Mortality among US Women

Emerging evidence suggests a potential impact of gastrointestinal function on cardiometabolic risk. Abnormal bowel movements have been related to various cardiovascular risk factors such as dyslipidemia, hypertension, diabetes, and altered metabolism of bile acids and gut microbiota. However, little is known about whether bowel movement frequency affects risk of cardiovascular disease (CVD) and mortality. In the Nurses' Health Study, bowel movement frequency was self-reported in 1982 by 86,289 women free from CVD and cancer. During up to 30 years of follow-up, we documented 7,628 incident CVD cases and 21,084 deaths. After adjustment for dietary intake, lifestyle, medication use, and other risk factors, as compared with women with daily bowel movement, having bowel movements more than once daily was significantly associated with increased risk of CVD (hazard ratio [HR]: 1.13; 95% confidence interval [CI]: 1.05-1.21), total mortality (HR: 1.17; 95% CI: 1.12-1.22), and cardiovascular mortality (HR: 1.17; 95% CI: 1.07-1.28). With further adjustment for body mass index and diabetes status, the association with total mortality remained significant (HR: 1.10; 95% CI: 1.06-1.15), whereas the associations with incident CVD and cardiovascular mortality were no longer significant. Our results suggest increased bowel movement frequency is a potential risk factor for premature mortality.

Subclinical Atherosclerosis in Patients With Inflammatory Bowel Diseases: A Systematic Review and Meta-Analysis

We evaluated the differences in major markers of cardiovascular (CV) risk between inflammatory bowel diseases (IBDs) and controls by a systematic review and a meta-analysis. We searched PubMed, EMBASE, and Cochrane databases for literature comparing CV risk markers in IBDs and controls. The overall mean carotid intima-media thickness (CIMT), flow-mediated dilation (FMD%), and carotid-femoral pulse wave velocity (cfPWV) difference between patients with IBDs and control groups were calculated. Twenty-eight studies were included in the meta-analysis, including 16 studies with data on CIMT, 7 studies reporting FMD%, and 9 studies on cfPWV. Compared to controls, patients with IBDs showed significantly higher CIMT (standardized mean difference [ SMD]: 0.534 mm; 95% confidence interval [CI], 0.230 to 0.838; P = .001), significantly lower FMD% ( SMD, -0.721%; 95% CI, -1.020 to -0.421; P < .0001), and significantly increased cfPWV ( SMD, 0.849; 95% CI, 0.589 to 1.110; P < .0001). When analyzing subgroups with ulcerative colitis and Crohn disease (CD), all results were still significant except CIMT in CD. Our findings support the current evidence for an elevated CV burden in patients with IBD and support the clinical utility of markers of subclinical atherosclerosis in the management of these patients.

Common links between metabolic syndrome and inflammatory bowel disease: Current overview and future perspectives

Metabolic syndrome (MS) features a constellation of central obesity, dyslipidemia, impaired glucose metabolism and often hypertension joined by insulin resistance and chronic inflammation. All these elements greatly raise patient's risk of cardiovascular disease and type 2 diabetes, resulting in an increased mortality. Metabolic syndrome affects approximately 20-25% of the world's adult population and thus it is essential to study its pathophysiology and seek new pharmacological targets. There is a thoroughly studied link between MS and inflammatory diseases of the gastrointestinal (GI) system, i.e. steatohepatitis. However, recent findings also indicate similarities in pathophysiological features between MS and inflammatory bowel disease (IBD), including adipose tissue dysregulation, inadequate immune response, and inflammation. In this review we aim to outline the pathophysiology of MS and emphasize the aspects revealed recently, such as mineralocorticoid activity, involvement of sex hormones and an accompanying increase in prolactin secretion. More importantly, we focus on the common links between MS and IBD. Finally, we describe new strategies and drug targets that may be utilized in MS therapy, namely adiponectin mimetics, GLP-1-based multi agonists, ABCA1 agonists and possible role of miRNA. We also discuss the possible utility of selected agents as adjuvants in IBD therapy.

Endothelial dysfunction in inflammatory bowel diseases: Pathogenesis, assessment and implications

Endothelial dysfunction is considered one of the etiological factors of inflammatory bowel disease (IBD). An inflammatory process leads to functional and structural changes in the vascular endothelium. An increase of leukocyte adhesiveness and leukocyte diapedesis, as well as an increased vascular smooth muscle tone and procoagulant activity is observed. Structural changes of the vascular endothelium comprise as well capillary and venule remodeling and proliferation of endothelial cells. Hypoxia in the inflammatory area stimulates angiogenesis by up-regulation of vascular endothelial growth factor, fibroblast growth factor and tumor necrosis factor-α. Inflammatory mediators also alter the lymphatic vessel function and impair lymph flow, exacerbating tissue edema and accumulation of dead cells and bacteria. The endothelial dysfunction might be diagnosed by the use of two main methods: physical and biochemical. Physical methods are based on the assessment of large arteries vasodilatation in response to an increased flow and receptors stimulation. Flow-mediated vasodilatation (FMD) is the method that is the most widely used; however, it is less sensitive in detecting early changes of the endothelium function. Most of the studies demonstrated a decrease of FMD in IBD patients but no changes in the carotic intima-media thickness. Biochemical methods of detecting the endothelial dysfunction are based on the assessment of the synthesis of compounds produced both by the normal and damaged endothelium. The endothelial dysfunction is considered an initial step in the pathogenesis of atherosclerosis in the general population. In IBD patients, the risk of cardiovascular diseases is controversial. Large, prospective studies are needed to establish the role of particular medications or dietary elements in the endothelial dysfunction as well to determine the real risk of cardiovascular diseases.

Long-term risk of cardiovascular and cerebrovascular disease after removal of the colonic microbiota by colectomy: a cohort study based on the Danish National Patient Register from 1996 to 2014

OBJECTIVES

The hypothesis of the study was that if the gut microbiota is involved in the development of atherosclerotic cardiovascular and cerebrovascular diseases (CVDs), total colectomy may reduce the long-term risk of CVDs. The aim was therefore to investigate the risk of CVD in patients after a total colectomy compared with patients undergoing other types of surgery, which are not expected to alter the gut microbiota or the CVD risk.

SETTING

The Danish National Patient Register including all hospital discharges in Denmark from 1996 to 2014.

PARTICIPANTS

Patients (n=1530) aged 45 years and above and surviving 1000 days after total colectomy without CVDs were selected and matched with five control patients who were also free of CVD 1000 days after other types of surgery. The five control patients were randomly selected from each of the three surgical groups: orthopaedic surgery, surgery in the gastrointestinal tract leaving it intact and other surgeries not related to the gastrointestinal tract or CVD (n=22 950).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the first occurring CVD event in any of the seven diagnostic domains (hypertensive disorders, acute ischaemic heart diseases, chronic ischaemic heart disease, cardiac arrhythmias, heart failure, cerebrovascular diseases and other arterial diseases) and the secondary outcomes were the first occurring event within each of these domains.

RESULTS

Estimated by Cox proportional hazard models, the HRs of the composite CVD end point for patients with colectomy compared with the control patients were not significantly reduced (HR=0.94, 95% confidence limits 0.85 to 1.04). Among the seven CVD domains, only the risk of hypertensive disorders was significantly reduced (HR=0.85, 0.73 to 0.98).

CONCLUSIONS

Colectomy did not reduce the general risk of CVD, but reduced the risk of hypertensive disorders, most likely due to salt and water depletion induced by colectomy. These results encourage a reappraisal of the associations between gut microbiota and CVD.