Low dose aspirin is associated with plasma chemerin levels and may reduce adipose tissue inflammation

Chitosan-Based Composite Membranes with Different Biocompatible Metal Oxide Nanoparticles: Physicochemical Properties and Drug-Release Study

Chitosan (CS) composite membranes were prepared using different biocompatible metal oxide nanoparticles (NPs): titanium dioxide (TiO₂); iron oxide (Fe₃O₄); and aluminum oxide (Al₂O₃). For each nanoparticle, the CS-based composite membranes were prepared with two NPs contents in the CS solution, high (H) and low (L) NPs concentrations. To establish both concentrations, the NPs saturation point in the CS polymeric matrix was determined. The influence of NP concentrations on the physicochemical properties of the CS films was assessed. The prepared CS membranes were characterized with different techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and zeta potential. It was found that the addition of NPs in the CS matrix improved both swelling and mechanical properties. Nanocomposite CS membranes could be prepared using Al₂O₃ NPs. Swelling experiments revealed different pH-sensitive mechanisms, which might be beneficial in biomedical applications since solute permeation through CS-based composite membranes could be controlled by adjusting environmental conditions. When aspirin transport (ASA) through the prepared membranes was carried out in different release media, SGF (simulating gastric fluid) and SIF (simulating intestinal fluid without enzymes), it was observed that the Fickian diffusion coefficient (D) was conditioned by the pH of the release solution. In SGIT (simulating gastrointestinal transit) medium, a transition time (t_trans) was detected due to the shrinkage of the CS polymeric chains, and the drug release depended not only on the Fickian's diffusion but also on the shrinkage of the biopolymer, obeying Peppas and Sahlin equation.

Adipocyte-derived chemerin rescues lipid overload-induced cardiac dysfunction

Chemerin, an adipocyte-secreted protein, has been recently suggested to be linked to metabolic syndrome and cardiac function in obese and diabetes mellitus. This study aimed to investigate the potential roles of adipokine chemerin on high fat-induced cardiac dysfunction. Chemerin (Rarres2) knockout mice, which were fed with either a normal diet or a high-fat diet for 20 weeks, were employed to observe whether adipokine chemerin affected lipid metabolism, inflammation, and cardiac function. Firstly, we found normal metabolic substrate inflexibility and cardiac function in Rarres2 ^-/- mice with a normal diet. Notably, in a high-fat diet, Rarres2 ^-/- mice showed lipotoxicity, insulin resistance, and inflammation, thus causing metabolic substrate inflexibility and cardiac dysfunction. Furthermore, by using in vitro model of lipid-overload cardiomyocytes, we found chemerin supplementation reversed the lipid-induced abnormalities above. Herein, in the presence of obesity, adipocyte-derived chemerin might function as an endogenous cardioprotective factor against obese-related cardiomyopathy.

The Effect of Low-Dose Aspirin on Frailty Phenotype and Frailty Index in Community-Dwelling Older Adults in the ASPirin in Reducing Events in the Elderly Study

BACKGROUND

Frailty is associated with chronic inflammation, which may be modified by aspirin. The purpose of this study was to determine whether low-dose aspirin reduces incident frailty in healthy older adult participants of the ASPirin in Reducing Events in the Elderly (ASPREE) trial.

METHODS

In the United States and Australia, 19 114 community-dwelling individuals aged ≥70 and older (U.S. minorities ≥65 years) and free of overt cardiovascular disease, persistent physical disability, and dementia were enrolled in ASPREE, a double-blind, placebo-controlled trial of 100-mg daily aspirin versus placebo. Frailty, a prespecified study end point, was defined according to a modified Fried frailty definition (Fried frailty) and the frailty index based on the deficit accumulation model (frailty index). Competing risk Cox proportional hazard models were used to compare time to incident frailty by aspirin versus placebo. Sensitivity analysis was conducted to include frailty data with and without imputation of missing data.

RESULTS

Over a median 4.7 years, 2 252 participants developed incident Fried frailty, and 4 451 had incident frailty according to the frailty index. Compared with placebo, aspirin treatment did not alter the risk of incident frailty (Fried frailty hazard ratio [HR]: 1.04, 95% confidence interval [CI] 0.96-1.13; frailty index HR: 1.03, 95% CI 0.97-1.09). The proportion of individuals classified as frail, and the trajectory in continuous frailty scores over time, were not different between the aspirin and placebo treatment groups. The results were consistent across a series of subgroups.

CONCLUSIONS

Low-dose aspirin use in healthy older adults when initiated in older ages does not reduce risk of incident frailty or the trajectory of frailty.

Innovative nanotools for vascular drug delivery: the atherosclerosis case study

Cardiovascular diseases are the leading cause of mortality in the Western world. Among them, atherosclerosis represents one of the most common diseases in the modern society due to a common sedentary lifestyle, high-fat diet, and smoking. In the near future, a new approach could potentially improve the therapy of vascular pathologies, where to date the non-specific treatments present several limitations, such as poor biodistribution, quick elimination from the body, and undesired side-effects. In this field, nanotechnology has a great potential for the therapy and diagnosis of atherosclerosis with more and more recent and innovative publications. This review is a critical analysis of the results reported in the literature regarding the different and possible new approaches for the therapy and diagnosis of atherosclerosis.

Serum Chemerin Concentration Is Associated with Proinflammatory Status in Chronic Coronary Syndrome

Background: Chemerin is an adipokine and a chemoattractant for leukocytes. Increased chemerin levels were observed in patients with coronary artery disease (CAD). We investigated associations between chemerin and biochemical measurements or body composition in CAD patients. Methods: In the study, we included patients with stable CAD who had undergone percutaneous coronary intervention (PCI) in the past. All patients had routine blood tests, and their insulin and chemerin serum levels were routinely measured. Body composition was assessed with the DEXA method. Results: The study group comprised 163 patients (mean age 59.8 ± years, 26% of females, n = 43). There was no significant difference in serum chemerin concentrations between patients with diabetes and the remaining ones: 306.8 ± 121 vs. 274.15 ± 109 pg/mL, p = 0.1. Chemerin correlated positively with the white blood cell (WBC) count, the neutrophil to lymphocyte ratio, hsCRP, all fractions of cholesterol, triglycerides, platelet count, fasting insulin, and c-peptide. Chemerin levels were also correlated with total fat mass but only in a subgroup with normal glucose metabolism. Conclusion: In patients with CAD, serum chemerin levels are correlated with inflammation markers, insulin resistance, and an unfavorable lipid profile. Correlation with fat mass is dependent on glucose metabolism status. Depending on the presence of diabetes/prediabetes, the mechanisms regulating chemerin secretion may be different.

Imaging and Targeting Coronary Artery Inflammation

Significance: Coronary artery disease (CAD) continues to be a leading cause of morbidity and mortality across the world despite significant progress in the prevention, diagnosis, and treatment of atherosclerotic disease. Recent Advances: The focus of the cardiovascular community has shifted toward seeking a better understanding of the inflammatory mechanisms driving residual CAD risk that is not modulated by current therapies. Significant progress has been achieved in revealing both proinflammatory and anti-inflammatory mechanisms, and how shift of the balance in favor of the former can drive the development of disease. Critical Issues: Advances in the noninvasive detection of coronary artery inflammation have been forthcoming. These advances include multiple imaging modalities, with novel applications of computed tomography both with and without positron emission tomography, and experimental ultrasound techniques. These advances will enable better selection of patients for anti-inflammatory treatments and assessment of treatment response. The rapid advancement in pharmaceutical design has enabled the production of specific antibodies against inflammatory pathways of atherosclerosis, with modest success to date. The pursuit of demonstrating the efficacy and safety of novel anti-inflammatory and/or proinflammatory resolution therapies for atherosclerotic CAD has become a major focus. Future Directions: This review seeks to provide an update of the latest evidence of all three of these highly related but disparate areas of inquiry: Our current understanding of the key mechanisms by which inflammation contributes to coronary artery atherosclerosis, the evidence for noninvasive assessment of coronary artery inflammation, and finally, the evidence for targeted therapies to treat coronary inflammation for the reduction of CAD risk. Antioxid. Redox Signal. 34, 1217-1243.

Chemerin causes lipid metabolic imbalance and induces passive lipid accumulation in human hepatoma cell line via the receptor GPR1

AIMS

Chemerin is abundant in patients with high body mass index and metabolic syndrome possibly due to its activation in adipogenesis and glucose intolerance. It has reported that sera chemerin is positively associated with fatty liver with little known underlying mechanisms. Our aim is to study the role of chemerin in hepatic lipid metabolism.

MAIN METHODS

Oil Red O staining and TG quantitative assay were used to detect intracellular lipid accumulation. PCR, QPCR and western blot were applied to measure lipid metabolism-related genes, CMKLR1, GPR1 and inflammation marker genes. Luciferase reporter assay was employed to uncover the down-regulation of proximate promoter activities of CMKLR1 and GPR1 by SREBP1c. Antibody neutralization assay was used to address the effects of chemerin on hepatic lipid synthesis.

KEY FINDINGS

Over-expression of chemerin led to passive lipid accumulation, in human hepatoma cell line HepG2. The disable form of chemerin (chemerin 21-158) and active chemerin (chemerin 21-157) performed strongly effects on lipid metabolism in HepG2 cells. Heterologous expression of CMKLR1 or G-protein coupled receptor1 (GPR1) played similar roles in hepatocyte lipid metabolism as chemerin. Chemerin exerted its effects on lipid metabolism via GPR1 in HepG2 cells. Furthermore, free fatty acids and high concentration insulin inhibited chemerin expression. Consistently, the key lipogenic transcription factor Sterol regulatory element binding protein 1c suppressed chemerin mRNA expression and proximate promoter activities of CMKLR1 and GPR1.

SIGNIFICANCE

It implied the existence of negative feed-back regulation and further confirmed the involvement of chemerin in hepatic lipid metabolism.

Association of Serum Chemerin Levels with Coronary Artery Disease: Pathogenesis and Clinical Research

Recent studies have revealed that chemerin plays an essential role in the development of cardiovascular diseases. Autopsy studies found a strong correlation between the secretion of chemerin in peripheral tissues and aortic and coronary atherosclerosis. Plasma chemerin is a marker of systemic inflammation and is associated with metabolic syndrome. Chemerin plays a vital role in vascular inflammation and atherogenesis. Plasma chemerin levels are increased in patients with dilated cardiomyopathy, and chemerin is associated with left ventricular dysfunction. In this review, we focus on chemerin expression, chemerin processing, its biological function, and its role in the diagnosis of cardiovascular diseases.

Effects of exercise training on inflammasome-related mediators and their associations to glucometabolic variables in patients with combined coronary artery disease and type 2 diabetes mellitus: Sub-study of a randomized control trial

BACKGROUND

Adipose tissue produces pro-inflammatory mediators involved in the atherosclerotic process. We investigated whether 12-month exercise training in patients with type 2 diabetes mellitus and coronary artery disease would reduce circulating levels and genetic expression of mediators in the interleukin-18, Caspase-1 and NLR pyrin domain containing 3 pathways. Correlations to glucometabolic variables; fasting glucose, HbA1c, duration of diabetes, insulin, C-peptide, insulin resistance (measured by homeostatic model assessment indexes - insulin resistance) and body mass index at baseline were further assessed.

METHODS

137 patients (aged 41-81 years, 17.2% female participants) were included and randomized to a 12-month exercise programme or to a control group. Fasting blood and adipose tissue samples were taken at inclusion and after 12 months.

RESULTS

No statistically significant difference in changes of any variable between the intervention and the control group was found. At baseline, a positive correlation between insulin and homeostatic model assessment indexes - insulin resistance, interleukin-18 expression in adipose tissue and an inverse correlation between some glucometabolic variables and leukocyte expression of NLR pyrin domain containing 3 and Caspase-1 were observed.

CONCLUSION

No significant effects of long-term exercise training were observed on the inflammasome-related mediators in our patients with combined coronary artery disease and type 2 diabetes mellitus. The observed correlations may indicate a pro-inflammatory state in adipose tissue by overweight and a compensatory downregulation of these mediators in circulating leucocytes.

G-Protein Coupled Receptor Targeting on Myeloid Cells in Atherosclerosis

Atherosclerosis, the underlying cause of the majority of cardiovascular diseases (CVDs), is a lipid-driven, inflammatory disease of the large arteries. Gold standard therapy with statins and the more recently developed proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have improved health conditions among CVD patients by lowering low density lipoprotein (LDL) cholesterol. Nevertheless, a substantial part of these patients is still suffering and it seems that 'just' lipid lowering is insufficient. The results of the Canakinumab Anti-inflammatory Thrombosis Outcome Study (CANTOS) have now proven that inflammation is a key driver of atherosclerosis and that targeting inflammation improves CVD outcomes. Therefore, the identification of novel drug targets and development of novel therapeutics that block atherosclerosis-specific inflammatory pathways have to be promoted. The inflammatory processes in atherosclerosis are facilitated by a network of immune cells and their subsequent responses. Cell networking is orchestrated by various (inflammatory) mediators which interact, bind and induce signaling. Over the last years, G-protein coupled receptors (GPCRs) emerged as important players in recognizing these mediators, because of their diverse functions in steady state but also and specifically during chronic inflammatory processes - such as atherosclerosis. In this review, we will therefore highlight a selection of these receptors or receptor sub-families mainly expressed on myeloid cells and their role in atherosclerosis. More specifically, we will focus on chemokine receptors, both classical and atypical, formyl-peptide receptors, the chemerin receptor 23 and the calcium-sensing receptor. When information is available, we will also describe the consequences of their targeting which may hold promising options for future treatment of CVD.

Circulating Chemerin Levels, but not the RARRES2 Polymorphisms, Predict the Long-Term Outcome of Angiographically Confirmed Coronary Artery Disease

Chemerin, a novel adipokine, has been associated with metabolic, inflammatory, and atherosclerotic diseases. We aimed to determine the genetic basis of chemerin levels by conducting a genome-wide association study (GWAS) and to investigate the role of RARRES2 polymorphisms and circulating chemerin levels in the long-term outcome of coronary artery disease (CAD). A total of 2197 participants from the Taiwan Biobank (TWB) were recruited for the GWAS analysis, and 481 patients with angiographically confirmed CAD were enrolled for long-term outcome analysis. One locus of genome-wide significance with a single independent association signal was identified in the GWAS for chemerin levels with the peak association at the RARRES2 gene promoter region polymorphism rs3735167 (p = 2.35 × 10⁻²¹). In the CAD population, borderline significance was noted between RARRES2 polymorphisms and chemerin levels, whereas high chemerin levels were associated with obesity, female sex, diabetes mellitus, hypertension, current smoking, high platelet and leukocyte counts, anemia, impaired renal function, high C-reactive protein (CRP) levels, and multi-vessel disease. Kaplan–Meier survival curves indicated that the patients with high chemerin and CRP levels, but not those with RARRES2 polymorphisms, had a lower survival rate and higher combined cerebral and cardiovascular event rates. Combined chemerin and CRP levels further revealed a stepwise increase in poor clinical outcomes from low- to high-risk subgroups. In conclusion, rs3735167 is the lead RARRES2 polymorphism for chemerin levels in Taiwanese. Chemerin levels, but not the rs3735167 genotypes, predicted the long-term outcome of CAD, especially when combined with CRP levels.

Unraveling the Interaction of Aspirin, Ticagrelor, and Rosuvastatin on the Progression of Atherosclerosis and Inflammation in Diabetic Mice

PURPOSE

We explored the effects of rosuvastatin, aspirin, ticagrelor, and clopidogrel, alone or in combinations on the progression of atherosclerosis and inflammasome activation in diabetic mice. Statins and ticagrelor increase the production of 15-epi-lipoxin A₄ via cyclooxygenase-2. Aspirin alone increases 15-epi-lipoxin A₄, but when combined with statins, cyclooxygenase-2 is completely blocked.

METHODS

ApoE^-/-/db⁺/db⁺ double-knockout mice received rosuvastatin (5 mg/kg/day), aspirin (25 mg/kg/day), ticagrelor (300 mg/kg/day), clopidogrel (75 mg/kg/day), or their combination for 14 weeks. Serum 15-epi-lipoxin A₄ levels and aortic wall cholesterol content, IL-1β, IL-6, and TNF-α levels, and plaque area were assessed.

RESULTS

Aspirin, ticagrelor, and rosuvastatin increased 15-epi-lipoxin A₄ levels. The combination of rosuvastatin + ticagrelor provided an additive effect. Aspirin attenuated the effect of both ticagrelor and rosuvastatin. Aspirin, ticagrelor, and rosuvastatin reduced the area of the atherosclerotic plaque. The combination of ticagrelor + rosuvastatin provided additive effects. There was a negative interaction when aspirin was combined with ticagrelor or rosuvastatin. Aspirin, ticagrelor, and rosuvastatin decreased serum IL-1β and IL-6 levels. There was no interaction between aspirin and ticagrelor or aspirin and rosuvastatin, whereas combining rosuvastatin and ticagrelor provided an additive effect. Aspirin, ticagrelor, and rosuvastatin all decreased TNF-α levels. Aspirin attenuated the effect of both ticagrelor and rosuvastatin, and there was no additive effect of combining ticagrelor + rosuvastatin.

CONCLUSIONS

We found an intricate interaction between aspirin, ticagrelor, and rosuvastatin, as aspirin reduced both ticagrelor and rosuvastatin ability to ameliorate inflammation and atherosclerosis. In contrast, we found additive effects when ticagrelor and rosuvastatin were combined.

Current and future therapies for addressing the effects of inflammation on HDL cholesterol metabolism

Cardiovascular disease (CVD) is a major cause of morbidity and mortality worldwide. Inflammatory processes arising from metabolic abnormalities are known to precipitate the development of CVD. Several metabolic and inflammatory markers have been proposed for predicting the progression of CVD, including high density lipoprotein cholesterol (HDL-C). For ~50 years, HDL-C has been considered as the atheroprotective 'good' cholesterol because of its strong inverse association with the progression of CVD. Thus, interventions to increase the concentration of HDL-C have been successfully tested in animals; however, clinical trials were unable to confirm the cardiovascular benefits of pharmaceutical interventions aimed at increasing HDL-C levels. Based on these data, the significance of HDL-C in the prevention of CVD has been called into question. Fundamental in vitro and animal studies suggest that HDL-C functionality, rather than HDL-C concentration, is important for the CVD-preventive qualities of HDL-C. Our current review of the literature positively demonstrates the negative impact of systemic and tissue (i.e. adipose tissue) inflammation in the healthy metabolism and function of HDL-C. Our survey indicates that HDL-C may be a good marker of adipose tissue health, independently of its atheroprotective associations. We summarize the current findings on the use of anti-inflammatory drugs to either prevent HDL-C clearance or improve the function and production of HDL-C particles. It is evident that the therapeutic agents currently available may not provide the optimal strategy for altering HDL-C metabolism and function, and thus, further research is required to supplement this mechanistic approach for preventing the progression of CVD.

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.

Platelets, diabetes and myocardial ischemia/reperfusion injury

Mechanisms underlying the pathogenesis of ischemia/reperfusion injury are particularly complex, multifactorial and highly interconnected. A complex and entangled interaction is also emerging between platelet function, antiplatelet drugs, coronary diseases and ischemia/reperfusion injury, especially in diabetic conditions. Here we briefly summarize features of antiplatelet therapy in type 2 diabetes (T2DM). We also treat the influence of T2DM on ischemia/reperfusion injury and how anti-platelet therapies affect post-ischemic myocardial damage through pleiotropic properties not related to their anti-aggregating effects. miRNA-based signature associated with T2DM and its cardiovascular disease complications are also briefly considered. Influence of anti-platelet therapies and different effects of healthy and diabetic platelets on ischemia/reperfusion injury need to be further clarified in order to enhance patient benefits from antiplatelet therapy and revascularization. Here we provide insight on the difficulty to reduce the cardiovascular risk in diabetic patients and report novel information on the cardioprotective role of widely used anti-aggregant drugs.

Patients with Rheumatoid Arthritis Show Altered Lipoprotein Profiles with Dysfunctional High-Density Lipoproteins that Can Exacerbate Inflammatory and Atherogenic Process

Objective

In order to identify putative biomarkers in lipoprotein, we compared lipid and lipoprotein properties between rheumatoid arthritis (RA) patients and control with similar age.

Methods

We analyzed four classes of lipoproteins (VLDL, LDL, HDL₂, HDL₃) from both male (n = 8, 69±4 year-old) and female (n = 25, 53±7 year-old) rheumatoid arthritis (RA) patients as well as controls with similar age (n = 13).

Results

Although RA group showed normal levels of total cholesterol (TC), low-density lipoprotein (LDL)-cholesterol, and glucose, however, the RA group showed significantly reduced high-density lipoprotein (HDL)-C level and ratio of HDL-C/TC. The RA group showed significantly elevated levels of blood triglyceride (TG), uric acid, and cholesteryl ester transfer protein (CETP) activity. The RA group also showed elevated levels of advanced glycated end (AGE) products in all lipoproteins and severe aggregation of apoA-I in HDL. As CETP activity and TG contents were 2-fold increased in HDL from RA group, paraoxonase activity was reduced upto 20%. Electron microscopy revealed that RA group showed much less HDL₂ particle number than control. LDL from the RA group was severely oxidized and glycated with greater fragmentation of apo-B, especially in female group, it was more atherogenic via phagocytosis.

Conclusion

Lipoproteins from the RA patients showed severely altered structure with impaired functionality, which is very similar to that observed in coronary heart patients. These dysfunctional properties in lipoproteins from the RA patients might be associated with high incidence of cardiovascular events in RA patients.

Inflammatory cytokines in atherosclerosis: current therapeutic approaches

The notion of atherosclerosis as a chronic inflammatory disease has intensified research on the role of cytokines and the way these molecules act and interact to initiate and sustain inflammation in the microenvironment of an atherosclerotic plaque. Cytokines are expressed by all types of cells involved in the pathogenesis of atherosclerosis, act on a variety of targets exerting multiple effects, and are largely responsible for the crosstalk among endothelial, smooth muscle cells, leucocytes, and other vascular residing cells. It is now understood that widely used drugs such as statins, aspirin, methotrexate, and colchicine act in an immunomodulatory way that may beneficially affect atherogenesis and/or cardiovascular disease progression. Moreover, advancement in pharmaceutical design has enabled the production of highly specific antibodies against key molecules involved in the perpetuation of the inflammatory cascade, raising hope for advances in the treatment of atherosclerosis. This review describes the actions and effects of these agents, their potential clinical significance, and future prospects.

Computational drug repositioning for peripheral arterial disease: prediction of anti-inflammatory and pro-angiogenic therapeutics

Peripheral arterial disease (PAD) results from atherosclerosis that leads to blocked arteries and reduced blood flow, most commonly in the arteries of the legs. PAD clinical trials to induce angiogenesis to improve blood flow conducted in the last decade have not succeeded. We have recently constructed PADPIN, protein-protein interaction network (PIN) of PAD, and here we combine it with the drug-target relations to identify potential drug targets for PAD. Specifically, the proteins in the PADPIN were classified as belonging to the angiome, immunome, and arteriome, characterizing the processes of angiogenesis, immune response/inflammation, and arteriogenesis, respectively. Using the network-based approach we predict the candidate drugs for repositioning that have potential applications to PAD. By compiling the drug information in two drug databases DrugBank and PharmGKB, we predict FDA-approved drugs whose targets are the proteins annotated as anti-angiogenic and pro-inflammatory, respectively. Examples of pro-angiogenic drugs are carvedilol and urokinase. Examples of anti-inflammatory drugs are ACE inhibitors and maraviroc. This is the first computational drug repositioning study for PAD.

Role of multifunctional Chemerin in obesity and preclinical diabetes

BACKGROUND

"Chemerin" is a multifuntional peptide involved in lipid and glucose metabolism. Elevated levels of this peptide have been associated with insulin resistance and systemic inflammation. This study aims to identify whether Chemerin along with other inflammatory markers (TNFα and hsCRP) can discriminate subjects with subclinical diabetes.

METHODOLOGY/FINDINGS

Fifty-two asymptomatic healthy volunteers and 22 chronic diabetics (T2DM) were enrolled in a cross sectional study design. They were subjected to a 75 g oral glucose tolerance test [OGTT (2-h glucose>200 mg/dL)] and were then classified as either newly diagnosed diabetics (NDM) (n=23) or healthy controls (n=29). Our results showed a higher Chemerin level in NDM (p<0.01; MWU) compared to controls and previously diagnosed DM. Using ROC analysis, Chemerin level in NDM and T2DM had AUC of 0.963 and 0.764 respectively, compared to healthy controls. We suggest that the cut off of 13.7 ng/ml of Chemerin can discriminate 73% of NDM subjects with impaired glucose level with 91% and 96% of sensitivity and specificity respectively. Elevated serum Chemerin in NDM group is a surrogate of impairment in glucose metabolism in obese individual.

CONCLUSIONS

Chemerin along with other inflammatory biomarkers suggest an ongoing inflammatory process in a high risk obese group that indicates a pre-diabetic state.

ChemR23, the receptor for chemerin and resolvin E1, is expressed and functional on M1 but not on M2 macrophages

ChemR23 is a G protein-coupled receptor that is triggered by two ligands, the peptide chemerin and the eicosapentaenoic acid-derived lipid mediator resolvin E1 (RvE1). Chemerin acts as a chemoattractant for monocytes and macrophages, whereas RvE1 promotes resolution of inflammation-inducing macrophage phagocytosis of apoptotic neutrophils. Although ChemR23-mediated signaling plays a role in mononuclear cell migration to inflamed tissue, as well as in the resolution of inflammation, its regulation in different polarization states of macrophages is largely unknown. We analyzed the expression and function of ChemR23 in monocytes and differently activated human primary macrophages. Using 5' RACE, we identified three transcription start sites and several splice variants of ChemR23 in both monocytes and macrophages. Although the promoters P1 and P3 are used equally in unpolarized macrophages, stimulation with LPS or IFN-γ leads to increased transcription from P3 in inflammatory M1 macrophages. Such ChemR23-expressing M1 macrophages are chemotactic to chemerin, whereas M2 macrophages not expressing ChemR23 surface receptor are not. Repolarization of ChemR23-expressing M1 macrophages with 10 nM RvE1 increases IL-10 transcription and phagocytosis of microbial particles, leading to a resolution-type macrophage distinct from the M2 phenotype. These results show that ChemR23 is tightly regulated in response to inflammatory and anti-inflammatory stimuli. The restricted expression of ChemR23 in naive and M1 macrophages supports the role of ChemR23 in the attraction of macrophages to inflamed tissue by chemerin and in the initiation of resolution of inflammation through RvE1-mediated repolarization of human M1 macrophages toward resolution-type macrophages.

Chemerin/chemR23 axis in inflammation onset and resolution

Chemerin is an adipokine secreted by adipocytes and associated with obesity, insulin resistance and metabolic syndrome. Different chemerin fragments with pro- or anti-inflammatory action can be produced, depending on the class of proteases predominating in the microenvironment. Chemerin binds to three receptors, especially to chemR23, expressed on various cells, as dendritic cells, macrophages and natural killer cells, regulating chemotaxis towards the site of inflammation and activation status. Recently, the chemerin/chemR23 axis has attracted particular attention for the multiple roles related to the control of inflammation, metabolism and cancerogenesis in different organs and systems as lung (allergy and cancer), skin (psoriasis, lupus, cancer, wound repair), cardiovascular system (lipid profile and atherosclerosis), reproductive apparatus (polycystic ovary syndrome, follicular homoeostasis), and digestive tract (inflammatory bowel diseases and cancer). This pathway may regulate immune responses by contributing both to the pathogenesis of inflammatory diseases and to the resolution of acute inflammation. Thus, chemerin-derived peptides or other substances that may affect the chemerin/chemR23 axis could be used in the future for the treatment of many diseases, including cancer at different sites.

Chemerin is a novel biomarker of acute coronary syndrome but not of stable angina pectoris

BACKGROUND

Recent evidence demonstrated that the circulating adipokines were associated with the onset of acute coronary syndrome (ACS) including unstable angina pectoris (UAP) and acute myocardial infarction (AMI). As a novel adipokine, chemerin has been related to atherosclerosis and the presence of coronary artery disease. However, the plasma levels of chemerin in patients with ACS have yet to be investigated.

METHODS

Plasma levels of chemerin and adiponectin were measured by an enzyme-linked immunosorbent assay (ELISA) in 60 patients with stable angina pectoris (SAP), 60 patients with UAP, 60 patients with AMI and 40 control patients. Left ventricular end-diastolic diameter (LVEDD) and left ventricular ejection fraction (LVEF) were measured using a GE ViVid E7 ultrasonography machine, and the severity of coronary stenosis in patients was estimated with a Gensini coronary score following coronary angiography.

RESULTS

Plasma chemerin levels were significantly higher in ACS patients than in the control and SAP groups, while plasma adiponectin levels were significantly lower in ACS patients than the control group. A correlation analysis revealed that plasma chemerin levels were positively correlated with the levels of C-reactive protein (CRP) (r = 0.29, P < 0.01) and LVEDD (r = 0.27, P < 0.01) but negatively correlated with LVEF (r = -0.45, P < 0.01) and that plasma adiponectin levels were positively correlated with LVEF (r = 0.53, P < 0.01) but negatively correlated with CRP (r = -0.33, P < 0.01) and LVEDD (r = -0.30, P < 0.01). Although significant correlations between chemerin, adiponectin and BMI or the Gensini coronary score were found in patients with SAP, neither chemerin nor adiponectin was correlated with BMI and the Gensini coronary score in patients with ACS. Furthermore, both chemerin (OR 1.103, 95% CI 1.065 to 1.142; P = 0.001) and adiponectin (OR 0.871, 95% CI 0.776 to 0.970; P = 0.018) were independently associated with the presence of ACS.

CONCLUSIONS

Chemerin is a novel biomarker of acute coronary syndrome but not of stable angina pectoris.