Serum adipokines in inflammatory bowel disease

Chemerin, visfatin, and vaspin serum levels in relation to bone mineral density in patients with inflammatory bowel disease

BACKGROUND

There is evidence that fat mass is correlated with bone mineral density (BMD) in inflammatory bowel disease (IBD), but data on the role of adipokines on this association are limited. The aim of this study was to investigate the serum levels of chemerin, visfatin, and vaspin, hormones that act as adipokines, in relation to BMD in patients with ulcerative colitis (UC) and Crohn's disease (CD).

PATIENTS AND METHODS

Serum from 120 IBD patients (68 CD, 52 UC) and 98 matched healthy controls (HC) was collected. Chemerin, visfatin, and vaspin levels were assessed using an enzyme-linked immunosorbent assay. BMD was determined for the lumbar spine and the proximal femur using dual-energy X-ray absorptiometry. Full-body composition scans were analyzed using enCORE software based on the absorptiometry system.

RESULTS

Serum chemerin was higher in IBD patients than HC [CD 13.67.1±5.8, UC 13.9±4.3 vs. HC 7.8±2.6 ng/ml, odds ratio (OR): 0.95, 95% confidence interval (CI) 0.93-0.98, P<0.0001]. Serum visfatin levels in CD patients were significantly higher than those in UC patients (9.3±14.01 vs. 6.5±7.2 ng/ml, OR: 0.86, 95% CI 0.80-0.92, P=0.039). In multivariate logistic regression analysis, a significant independent association of osteoporosis (T-score ≤2.5 SD) with age (OR: 1.04, 95% CI 1.01-1.08, P=0.02), visfatin (OR: 0.78, 95% CI 0.63-0.97, P=0.02), and chemerin levels (OR: 0.83, 95% CI 0.70-0.98, P=0.03), but not with BMI or body composition, was found.

CONCLUSION

Serum visfatin and chemerin levels are associated with the development of osteoporosis in IBD. These results suggest a role of visfatin and chemerin in the pathophysiology of osteoporosis in IBD.

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.

Signaling Interplay between Bone Marrow Adipose Tissue and Multiple Myeloma cells

In the year 2000, Hanahan and Weinberg (1) defined the six Hallmarks of Cancer as: self-sufficiency in growth signals, evasion of apoptosis, insensitivity to antigrowth mechanisms, tissue invasion and metastasis, limitless replicative potential, and sustained angiogenesis. Eleven years later, two new Hallmarks were added to the list (avoiding immune destruction and reprograming energy metabolism) and two new tumor characteristics (tumor-promoting inflammation and genome instability and mutation) (2). In multiple myeloma (MM), a destructive cancer of the plasma cell that grows predominantly in the bone marrow (BM), it is clear that all these hallmarks and characteristics are in play, contributing to tumor initiation, drug resistance, disease progression, and relapse. Bone marrow adipose tissue (BMAT) is a newly recognized contributor to MM oncogenesis and disease progression, potentially affecting MM cell metabolism, immune action, inflammation, and influences on angiogenesis. In this review, we discuss the confirmed and hypothetical contributions of BMAT to MM development and disease progression. BMAT has been understudied due to technical challenges and a previous lack of appreciation for the endocrine function of this tissue. In this review, we define the dynamic, responsive, metabolically active BM adipocyte. We then describe how BMAT influences MM in terms of: lipids/metabolism, hypoxia/angiogenesis, paracrine or endocrine signaling, and bone disease. We then discuss the connection between BMAT and systemic inflammation and potential treatments to inhibit the feedback loops between BM adipocytes and MM cells that support MM progression. We aim for researchers to use this review to guide and help prioritize their experiments to develop better treatments or a cure for cancers, such as MM, that associate with and may depend on BMAT.

Serum Visfatin Levels in Ulcerative Colitis

BACKGROUND

Previous studies have suggested that adipokines play a role in inflammatory bowel disease by inducing proinflammatory cytokines, but it is uncertain whether visfatin is causally involved in ulcerative colitis (UC). We evaluated visfatin levels in patients who presented with UC flares before and after treatment.

METHODS

In this cohort study, we assessed 31 patients with UC in the activation period and remission in the same patients after treatment, and a healthy control group, consisting of 29 persons, at a single academic medical centre between 2010 and 2013. Disease severity was evaluated clinically using Trulove and Witt's criteria.

RESULTS

Serum visfatin levels did not vary according to the extent of disease and were significantly higher in patients in the activation period (7.77 ± 2.41 ng/ml) than in remission (6.18 ± 2.04 ng/ml) and the healthy controls (6.54 ± 2.20 ng/ml; P < 0.01 and < 0.05, respectively). In a comparison of patients in the inactive period with the control group, there was no statistically significant difference (P > 0.05). To assess activation of the disease, a visfatin cut-off point for active UC was determined as 6.40, with sensitivity, specificity, positive predictive value (PPV) and negative predictive values (NPV) of 72%, 52%, 66.7% (43.0-85.4) and 50.0% (29.1-70.9), respectively.

CONCLUSIONS

The visfatin level was higher in the active group than in post-treatment remission and the healthy control group. Sensitivity and specificity were similar to other inflammatory markers for assessing clinical activity, which did not improve clinical outcomes in patients with acute respiratory distress syndrome (ARDS). These findings did not provide a rationale for assessment of UC activation.

Local chemerin levels are positively associated with DSS-induced colitis but constitutive loss of CMKLR1 does not protect against development of colitis

Inflammatory bowel disease (IBD) is a family of disorders including ulcerative colitis and Crohn's disease that are characterized by chronic and relapsing intestinal inflammation. Increased production of proinflammatory mediators, possibly combined with low expression of anti-inflammatory mediators, is thought to promote the development and progression of IBD. In the current study, we demonstrate that expression, secretion, and processing of chemerin, a potent chemoattractant for cells expressing chemokine-like receptor 1 (CMKLR1), increased in the cecum and colon along a gradient positively associated with the severity of inflammation in dextran sodium sulfate (DSS)-induced colitis. We also show that levels of circulating bioactive chemerin increased following DSS treatment. At both 6-8 and 14-16 weeks of age, CMKLR1 knockout mice developed signs of clinical illness more slowly than wild type and had changes in circulating cytokine levels, increased spleen weight, and increased local chemerin secretion following DSS treatment. However, knockout mice ultimately developed similar levels of clinical illness and local inflammation as wild type. Finally, contrary to previous reports, intraperitoneal injection of bioactive chemerin had no effect on the severity of DSS-induced colitis. This suggests that local chemerin levels have a greater impact than circulating levels in the pathogenesis of colitis. Considered altogether, bioactive chemerin represents a novel biomarker for IBD severity, although strategies to modulate endogenous chemerin signaling other than chronic CMKLR1 loss are necessary in order to exploit chemerin as a therapeutic target for the treatment of IBD.

Adipokines influence the inflammatory balance in autoimmunity

Over the past few decades, our understanding of the role of adipose tissue has changed dramatically. Far from simply being a site of energy storage or a modulator of the endocrine system, adipose tissue has emerged as an important regulator of multiple important processes including inflammation. Adipokines are a diverse family of soluble mediators with a range of specific actions on the immune response. Autoimmune diseases are perpetuated by chronic inflammatory responses but the exact etiology of these diseases remains elusive. While researchers continue to investigate these causes, millions of people continue to suffer from chronic diseases. To this end, an increased interest has developed in the connection between adipose tissue-secreted proteins that influence inflammation and the onset and perpetuation of autoimmunity. This review will focus on recent advances in adipokine research with specific attention on a subset of adipokines that have been associated with autoimmune diseases.

Significance of expression of adiponectin in patients with ulcerative colitis

AIM: To investigate the adponectin levels in serum and intestinal tissue of patients with ulcerative colitis and to analyze the clinical significance.

METHODS: Serum adiponectin levels were detected by enzyme linked immunosorbent assay (ELISA) and the presence of adiponectin in the intestinal mucosa was detected by immunohistochemical staining in 38 patients with ulcerative colitis and 10 healthy controls. The correlation of adiponectin level with the clinical characteristics of ulcerative colitis was analyzed.

RESULTS: The levels of adiponectin in serum and intestinal mucosa of patients with ulcerative colitis were significantly higher than those in the normal control group, and can reflect the severity of ulcerative colitis to a certain extent. There was a significant positive correlation between adiponectin level in the intestinal mucosa and disease activity index in patients with active ulcerative colitis (P < 0.05).

CONCLUSION: Adiponectin may play an important role in the pathogenesis of ulcerative colitis.