Lower serum levels of Meteorin-like/Subfatin in patients with coronary artery disease and type 2 diabetes mellitus are negatively associated with insulin resistance and inflammatory cytokines

Correlation of serum Meteorin-like (Metrnl) level with type 2 diabetic peripheral neuropathy

OBJECTIVE

Meteorin-like (Metrnl), a secreted myokine, is a newly discovered neurotrophic factor. The aim of this study was to determine if there is a correlation between the Metrnl level and diabetic peripheral neuropathy (DPN).

METHODS

The investigation was conducted on a sample of 80 patients with type 2 diabetes mellitus (T2DM) and 60 healthy controls. The T2DM patients were categorized into two subgroups based on skin biopsy: the DPN subgroup (n = 20) and the diabetes without neuropathy subgroup (n = 60).

RESULTS

The T2DM groups had higher serum Metrnl concentrations compared with the controls. The serum Metrnl concentration was significantly lower in the DPN group than in T2DM patients without neuropathy. Logistic regression analysis demonstrated a notable correlation between serum Metrnl and DPN (OR: 0.997, 95% CI: 0.995-1.000, P < 0.05). Serum Metrnl level was negatively correlated with age and SBP after a simple logistic regression analysis.

CONCLUSION

Serum Metrnl concentration is independently correlated with DPN.

Sexual dimorphism in thermogenic regulators and metrnl expression in adipose tissue of offspring mice exposed to maternal and postnatal overnutrition

Current study investigated the impact of maternal and postnatal overnutrition on phenotype of adipose, in relation to offspring thermogenesis and sex. Female C57BL/6 J mice were fed with CHOW or high fat diet (HFD) for 2 weeks before mating, throughout gestation and lactation. At weaning, pups were fed to 9 weeks old with CHOW or HFD, which resulted in four groups for each gender--male or female: CHOW-CHOW (CC), CHOW-HFD (CH), HFD-CHOW (HC), HFD-HFD (HH). Maternal and post-weaning HFD enhanced thermogenic factors such as Acox1, Dio2 and Cox8b in iBAT of male and female offspring, but increased SIRT1, PGC-1α and UCP1 only in female. However, Acox1, Dio2 and Cox8b mRNA expression and SIRT1, PGC-1α and UCP1 protein expression were only enhanced upon maternal and post-weaning HFD in sWAT and pWAT of female offspring. Increased metrnl expression in adipose were observed in sex- and depot-specific manner, while enhanced circulating metrnl level was only observed in male offspring undergoing maternal HFD. Palmitic acid changed metrnl expression during preadipocytes differentiation and siRNA-mediated knockdown of metrnl inhibited preadipocyte differentiation. Female offspring were more prone to resist adverse outcomes induced by maternal and post-weaning overnutrition, which probably related to metrnl expression and thermogenesis.

Chronic vascular pathogenesis results in the reduced serum Metrnl levels in ischemic stroke patients

Metrnl is a secreted protein involved in neurite outgrowth, insulin sensitivity, immunoinflammatory responses, blood lipids and endothelial protection. In this study, we investigated the role of Metrnl in ischemic stroke. Fifty-eight ischemic stroke patients (28 inpatient patients within 2 weeks of onset and 30 emergency patients within 24 h of onset) and 20 healthy controls were enrolled. Serum Metrnl was measured by enzyme-linked immunosorbent assay. We showed that serum Metrnl levels were significantly reduced in both inpatient and emergency patient groups compared with the controls. Different pathological causes for ischemic stroke such as large artery atherosclerosis and small artery occlusion exhibited similar reduced serum Metrnl levels. Transient ischemic attack caused by large artery atherosclerosis without brain infarction also had lower serum Metrnl levels. Metrnl was correlated with some metabolic, inflammatory and clotting parameters. Reduced serum Metrnl was associated with the severity of intracranial arterial stenosis and the presence of ischemic stroke. In order to elucidate the mechanisms underlying the reduced serum Metrnl levels, we established animal models of ischemic stroke in normal mice, atherosclerotic apolipoprotein E-knockout mice and Metrnl-knockout mice by middle cerebral artery occlusion (MCAO) using intraluminal filament or electrocoagulation. We demonstrated that serum Metrnl levels were significantly lower in atherosclerosis mice than normal mice, whereas acute ischemic stroke injury in normal mice and atherosclerosis mice did not alter serum Metrnl levels. Metrnl knockout did not affect acute ischemic stroke injury and death. We conclude that reduced serum Metrnl levels are attributed to the chronic vascular pathogenesis before the onset of ischemic stroke. Metrnl is a potential target for prevention of ischemic stroke.

Immunomodulation through Nutrition Should Be a Key Trend in Type 2 Diabetes Treatment

An organism's ability to function properly depends not solely on its diet but also on the intake of nutrients and non-nutritive bioactive compounds that exert immunomodulatory effects. This principle applies both to healthy individuals and, in particular, to those with concomitant chronic conditions, such as type 2 diabetes. However, the current food industry and the widespread use of highly processed foods often lead to nutritional deficiencies. Numerous studies have confirmed the occurrence of immune system dysfunction in patients with type 2 diabetes. This article elucidates the impact of specific nutrients on the immune system function, which maintains homeostasis of the organism, with a particular emphasis on type 2 diabetes. The role of macronutrients, micronutrients, vitamins, and selected substances, such as omega-3 fatty acids, coenzyme Q10, and alpha-lipoic acid, was taken into consideration, which outlined the minimum range of tests that ought to be performed on patients in order to either directly or indirectly determine the severity of malnutrition in this group of patients.

The Function and Mechanism of Anti-Inflammatory Factor Metrnl Prevents the Progression of Inflammatory-Mediated Pathological Bone Osteolytic Diseases

Metrnl, recently identified as an adipokine, is a secreted protein notably expressed in white adipose tissue, barrier tissues, and activated macrophages. This adipokine plays a pivotal role in counteracting obesity-induced insulin resistance. It enhances adipose tissue functionality by promoting adipocyte differentiation, activating metabolic pathways, and exerting anti-inflammatory effects. Extensive research has identified Metrnl as a key player in modulating inflammatory responses and as an integral regulator of muscle regeneration. These findings position Metrnl as a promising biomarker and potential therapeutic target in treating inflammation-associated pathologies. Despite this, the specific anti-inflammatory mechanisms of Metrnl in immune-mediated osteolysis and arthritis remain elusive, warranting further investigation. In this review, we will briefly elaborate on the role of Metrnl in anti-inflammation function in inflammation-related osteolysis, arthritis, and pathological bone resorption, which could facilitate Metrnl's clinical application as a novel therapeutic strategy to prevent bone loss. While the pathogenesis of elbow stiffness remains elusive, current literature suggests that Metrnl likely exerts a pivotal role in its development.

Low Levels of Metrnl are Linked to the Deterioration of Diabetic Kidney Disease

Objective

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease. Metrnl is a secreted protein that plays an important role in kidney disease. The aim of this study was to investigate DKD-related factors and the correlation between serum Metrnl levels and the severity of DKD.

Methods

Ninety-six type 2 diabetes mellitus (T2DM) patients and 45 DKD patients were included in the study. A range of parameters were measured simultaneously, including waist-to-hip ratio (WHR), body mass index (BMI), urinary albumin/creatinine ratio (UACR), monocyte-lymphocyte ratio (MLR), albumin/globulin (A/G), liver and kidney function, blood lipid profile, islet function, and others. Subsequently, the related factors and predictive significance of DKD were identified. The correlation between the relevant factors of DKD and serum Metrnl levels with DKD was evaluated.

Results

The duration of the disease (OR: 1.12, 95% CI: 1.01-1.24, P=0.031), hypertension (OR: 4.86, 95% CI: 1.16-20.49, P=0.031), fasting blood glucose (OR: 1.23, 95% CI: 1.03-1.48, P=0.025), WHR (OR: 2.53, 95% CI: 1.03-6.22, P=0.044), and MLR (OR: 1.91, 95% CI: 1.18-3.08, P=0.008) are independent risk factors for DKD (P < 0.05). Conversely, A/G (OR: 0.13, 95% CI: 0.02-0.76, P=0.024) and Metrnl (OR: 0.99, 95% CI: 0.98-1.00, P=0.001) have been identified as protective factors against DKD. Furthermore, the level of Metrnl was negatively correlated with the severity of DKD (rs=-0.447, P<0.001). The area under receiver operating characteristic (ROC) curves for the diagnostic accuracy of Metrnl for DKD is 0.765 (95% CI: 0.686-0.844).

Conclusion

The duration of the disease, hypertension, fasting blood glucose, WHR, and MLR are major risk factors for DKD. Metrnl and A/G are protective factors for DKD. Serum Metrnl concentrations are inversely correlated with DKD severity.

Serum Metrnl is Decreased in Metabolic Dysfunction-Associated Fatty Liver Disease: A Case-Control Study

Context

Metrnl is a novel adipokine mainly produced by white adipose tissue, which plays important roles in insulin sensitization, and energy homeostasis. However, information about the function of Metrnl in Metabolic dysfunction-associated fatty liver disease (MAFLD) remains unclear.

Methods

This is a control study, which enrolled 176 adults with MAFLD and 176 normal controls. They were matched in body mass index (BMI), age, and sex. Serum Metrnl was determined by ELISA. Other biochemical data were also collected.

Results

Compared to the controls, circulating Metrnl was prominently decreased in the MAFLD adults (P<0.001). Next, binary logistic regression model indicated that sex, waist circumference (WC), triglyceride, γ-gamma glutamyl transferase(γ-GGT), and Metrnl was independently associated with MAFLD. Further, as Metrnl levels elevated across its tertiles, the rate of MAFLD decreased (67.52, 66.95, and 15.38%; P value for trend<0.001). Data from multivariate logistic regression models evidenced that compared with the lowest tertile of Metrnl, the odds ratio of MAFLD was 0.023(95% CI 0.006-0.086, P<0.001) for the highest tertile after adjusting for potential confounders. Besides, area under ROC curve of Metrnl for diagnosis MAFLD was 0.755(95% CI 0.705-0.805). Metrnl was positively correlated with diastolic blood pressure, WC, BMI, systolic blood pressure, γ-GGT, and Creatinine in MAFLD. Finally, we found systolic blood pressure and Creatinine were independently related to serum Metrnl in MAFLD.

Conclusion

Serum Metrnl is reduced in adult with MAFLD. The results suggest that Metrnl may be a protective factor associated with the pathogenesis of MAFLD.

Meteorin-like protein is associated with a higher risk profile and predicts a worse outcome in patients with STEMI

INTRODUCTION AND OBJECTIVES

Meteorin-like protein (Metrnl) is a cytokine involved in the attenuation of inflammation. In patients with heart failure, high levels of this biomarker are associated with a worse outcome. In this study, we evaluated the circulating levels and prognostic value of Metrnl in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

We enrolled STEMI patients undergoing primary percutaneous coronary intervention. Circulating Metrnl levels were measured in peripheral blood 12hours after symptom onset. The primary endpoint was a composite of all-cause mortality or nonfatal myocardial infarction (MI) at 3 years.

RESULTS

We studied 381 patients (mean age 61 years, 21% female, 8% Killip class III/IV). Metrnl levels were associated with age, cardiovascular risk factors and the extent of coronary artery disease, as well as with STEMI complications, particularly heart failure and cardiogenic shock. Multivariable Cox regression analysis revealed that Metrnl independently predicted all-cause death or nonfatal MI at 3 years (HR, 1.86; 95%CI, 1.23-2.81; P=.003). Moreover, patients in the highest tertile (> 491.6 pg/mL) were at higher risk for the composite endpoint than those in the lowest tertiles (HR, 3.24; 95%CI, 1.92-5.44; P <.001), even after adjustment by age, diabetes mellitus, cardiac arrest, Killip-Kimball III/IV class, left ventricular ejection fraction, and creatinine clearance (HR, 1.90; 95%CI, 1.10-3.29; P=.021).

CONCLUSIONS

Circulating Metrnl levels are associated with complications during the acute phase of STEMI and independently predict a worse outcome in these patients.

A meta-analysis of the relationship between serums metrnl-like protein/subfatin and risk of type 2 diabetes mellitus and coronary artery disease

There have been inconsistent reports that Metrnl-like protein, a new adipokine, is associated with the risk of metabolic syndrome (MetS), type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD). A systematic search in PubMed, Scopus, Web of Science, and Google scholar databases were conducted up until 24 November 2020. Ten eligible studies were included in this meta-analysis. The overall results showed that there was no significant association between serum Metrnl levels and risk of T2DM and CAD in patients compared with healthy control (SMD= -0.717 and 95%CI -1.572_0.139, p = .1). However, in subgroup analysis, there was a significant association between a BMI ≥ 25 and the serum level of Metrnl-like protein (SMD= -0.688 and 95%CI -1.348_-0.028 p = .041), indicating a potential inverse connection between serum Metrnl and the adiposity. Further well-designed studies are needed to explain the more subtle roles of Metrnl in metabolic disorders like T2DM and CAD.

Meteorin-like Protein and Asprosin Levels in Children and Adolescents with Obesity and Their Relationship with Insulin Resistance and Metabolic Syndrome

OBJECTIVE

Two newly discovered adipokines, including Meteorin-like protein (Metrnl) and asprosin, have been implicated in glucose and insulin metabolism. This study aimed to investigate the associations of these adipokines with obesity in children and adolescents.

METHODS

This study was performed on 35 normal-weight children and 35 children with obesity. Anthropometric and biochemical parameters were determined. Serum concentrations of Metrnl, asprosin, and insulin were measured using enzyme-linked immunosorbent assay.

RESULTS

Metrnl level was significantly lower in obese children than normal-weight children. Additionally, Metrnl was negatively correlated with body mass index (BMI), insulin, waist-to-hip ratio, and homeostatic model assessment of insulin resistance (HOMA-IR). Our results also revealed that circulating asprosin levels were significantly increased in obese children compared to the control subjects and were positively correlated with BMI, insulin, HOMA-IR, cholesterol, and LDL-C.

CONCLUSION

Obesity is accompanied by significant alterations in Metrnl and asprosin and therefore these adipokines, especially Metrnl, are suggested as new promising therapeutic targets for obesity and its associated metabolic imbalances.

Betatrophin, elabela, asprosin, glucagon and subfatin peptides in breast tissue, blood and milk in gestational diabetes

We investigated the presence of asprosin (ASP), betatrophin, elabela (ELA), glucagon and subfatin (SUB) in the milk of mothers with gestational diabetes mellitus (GDM) and compared their levels with blood levels. We also investigated whether these peptides are synthesized by the breast. We investigated 12 volunteer mothers with GDM and 14 pregnant non-GDM control mothers. The peptides were measured using ELISA and their tissue localization was determined using immunohistochemistry. Breast milk contains ASP, betatrophin, ELA, glucagon and SUB. The amount of the peptides ranged from highest to the lowest in colostrum, transitional milk and mature milk. The amount of peptides in the milk was greater than for blood. The peptides, except for ELA, were increased in milk and blood by GDM. Betatrophin and ELA are synthesized in the connective tissue of the breast. ASP, glucagon and SUB are synthesized in the alveolar tissue of the breast. These peptides in breast milk may contribute to the development of the gastrointestinal tract of newborns and infants.

Novel targets for potential therapeutic use in Diabetes mellitus

Future targets are a promising prospect to overcome the limitation of conventional and current approaches by providing secure and effective treatment without compromising patient compliance. Diabetes mellitus is a fast-growing problem that has been raised worldwide, from 4% to 6.4% (around 285 million people) in past 30 years. This number may increase to 430 million people in the coming years if there is no better treatment or cure is available. Ageing, obesity and sedentary lifestyle are the key reasons for the worsening of this disease. It always had been a vital challenge, to explore new treatment which could safely and effectively manage diabetes mellitus without compromising patient compliance. Researchers are regularly trying to find out the permanent treatment of this chronic and life threatening disease. In this journey, there are various treatments available in market to manage diabetes mellitus such as insulin, GLP-1 agonist, biguanides, sulphonyl ureas, glinides, thiazolidinediones targeting the receptors which are discovered decade before. PPAR, GIP, FFA1, melatonin are the recent targets that already in the focus for developing new therapies in the treatment of diabetes. Inspite of numerous preclinical studies very few clinical data available due to which this process is in its initial phase. The review also focuses on the receptors like GPCR 119, GPER, Vaspin, Metrnl, Fetuin-A that have role in insulin regulation and have potential to become future targets in treatment for diabetes that may be effective and safer as compared to the conventional and current treatment approaches.

Meteorin-like/Metrnl, a novel secreted protein implicated in inflammation, immunology, and metabolism: A comprehensive review of preclinical and clinical studies

Meteorin-like, also known as Metrnl, Meteorin-β, Subfatin, and Cometin, is a novel secreted protein exerting pleiotropic effects on inflammation, immunology, and metabolism. Earlier research on this hormone focused on regulating energy expenditure and glucose homeostasis. Consequently, several studies attempted to characterize the molecule mechanism of Metrnl in glucose metabolism and obesity-related disorders but reported contradictory clinical results. Recent studies gradually noticed its multiple protective functions in inflammatory immune regulations and cardiometabolic diseases, such as inducing macrophage activation, angiogenesis, tissue remodeling, bone formation, and preventing dyslipidemias. A comprehensive understanding of this novel protein is essential to identify its significance as a potential therapeutic drug or a biomarker of certain diseases. In this review, we present the current knowledge on the physiology of Metrnl and its roles in inflammation, immunology, and metabolism, including animal/cell interventional preclinical studies and human clinical studies. We also describe controversies regarding the data of circulation Metrnl in different disease states to determine its clinical application better.

Low serum levels of meteorin-like/subfatin is related to obesity and insulin resistance

Introduction: Meteorin-like (Metrnl), also known as subfatin is a newly discovered adipokine of adipocyte origin that may play a role in obesity and insulin resistance. The current study aimed to investigate the association between subfatin and biochemical values, demographic characteristics, and insulin resistance in obese patients and healthy controls.Methods: This cross-sectional study included 59 obese patients with sex and age-matched group of 41 healthy controls. An enzyme-linked immunosorbent assay (ELISA) was used to measure the serum levels of Subfatin (Metrnl), and the correlations of Metrnl level with anthropometric parameters, HOMA index, and biochemical measurements were assessed.Results: The levels of BMI (p&lt;0.001), insulin (p=0.002), and HOMA-IR score (p&lt;0.001) were significantly higher in obese patients than controls. The serum levels of Subfatin were found to be lower in obese patients (1.85 [1.35–5.51] ng/ml) compared to the healthy controls (21.82 [12.61–27.76] ng/ml) (p&lt;0.001). Subfatin had a significantly negative relationship with age (r =-0.250, p=0.012), weight (r =-0.373, p=0.001), BMI (r =-0.492, p=0.001), HbA1c (r =-0.209, p=0.037), LDL (r =-0.264, p=0.008), HOMA-IR (r =-0.223, p=0.026), and glucose (r =-0.376, p&lt;0.001). There was a significantly positive correlation between subfatin and height (r=0.321, p=0.001).Conclusion: These results show that levels of subfatin were decreased in obese patients. There is a relationship between circulating amounts of subfatin hormone and age, weight, height, LDL-cholesterol, glucose, hbA1c, and HOMA-IR. Subfatin might be a new biomarker of obesity and insulin resistance.Keywords: Meteorin-like/subfatin, adiposity, insulin resistance, adipokines, biomarkers, diabetes mellitus type 2

Endothelial METRNL determines circulating METRNL level and maintains endothelial function against atherosclerosis

METRNL is a recently identified secreted protein with emerging functions. This study is to find major cellular source of circulating METRNL and to determine METRNL novel function. Here, we show METRNL is abundant in human and mouse vascular endothelium and released by endothelial cells using endoplasmic reticulum-Golgi apparatus pathway. By creating endothelial cell-specific Metrnl knockout mice, combined with bone marrow transplantation to produce bone marrow-specific deletion of Metrnl, we demonstrate that most of circulating METRNL (approximately 75%) originates from the endothelial cells. Both endothelial and circulating METRNL decrease in atherosclerosis mice and patients. By generating endothelial cell-specific Metrnl knockout in apolipoprotein E-deficient mice, combined with bone marrow-specific deletion of Metrnl in apolipoprotein E-deficient mice, we further demonstrate that endothelial METRNL deficiency accelerates atherosclerosis. Mechanically, endothelial METRNL deficiency causes vascular endothelial dysfunction including vasodilation impairment via reducing eNOS phosphorylation at Ser1177 and inflammation activation via enhancing NFκB pathway, which promotes the susceptibility of atherosclerosis. Exogenous METRNL rescues METRNL deficiency induced endothelial dysfunction. These findings reveal that METRNL is a new endothelial substance not only determining the circulating METRNL level but also regulating endothelial function for vascular health and disease. METRNL is a therapeutic target against endothelial dysfunction and atherosclerosis.

Energy metabolism and frailty: The potential role of exercise-induced myokines - A narrative review

Frailty is a complex condition that emerges from dysregulation in multiple physiological systems. Increasing evidence suggests the potential role of age-related energy dysregulation as a key driver of frailty. Exercise is considered the most efficacious intervention to prevent and even ameliorate frailty as it up-tunes and improves the function of several related systems. However, the mechanisms and molecules responsible for these intersystem benefits are not fully understood. The skeletal muscle is considered a secretory organ with endocrine functions that can produce and secrete exercise-related molecules such as myokines. These molecules are cytokines and other peptides released by muscle fibers in response to acute and/or chronic exercise. The available evidence supports that several myokines can elicit autocrine, paracrine, or endocrine effects, partly mediating inter-organ crosstalk and also having a critical role in improving cardiovascular, metabolic, immune, and neurological health. This review describes the current evidence about the potential link between energy metabolism dysregulation and frailty and provides a theoretical framework for the potential role of myokines (via exercise) in counteracting frailty. It also summarizes the physiological role of selected myokines and their response to different acute and chronic exercise protocols in older adults.

Evaluation of changing the pattern of CTRP5 and inflammatory markers levels in patients with coronary artery disease and type 2 diabetes mellitus

PURPOSE

It has recently found that adipokines, play a numerous functional roles in inflammation, lipids and glucose metabolism and in the pathogenically conditions such as atherosclerosis and insulin resistance. Therefore, for the first time we aimed the present study to evaluating serum levels of CTRP5 and inflammatory cytokines patients with CAD and T2DM in comparison with controls.

METHODS

This study was done on 44 patients with CAD, 45 type 2 diabetes mellitus (T2DM), 41 CAD + T2DM and 41 controls. Serum levels of TNF-α, IL-6, MCP-1 and CTRP5 were investigated by ELISA method.

RESULTS

The CTRP5 levels of all patients groups were lower in comparison with control group. There was a significant negative relationship between CTRP5 levels and cytokines concentration in the studied patients.

CONCLUSIONS

Our findings suggested a potential role of CTRP5 in inflammatory process of underlying atherosclerosis and diabetes; however, more studies are needed to support these finding.

Changes in the expression of meteorin-like (METRNL), irisin (FNDC5), and uncoupling proteins (UCPs) after bariatric surgery

OBJECTIVE

Bariatric surgery is currently the most effective treatment for severe obesity. This study aims to investigate the changes in expression levels of meteorin-like protein (METRNL), irisin (FNDC5), and uncoupling proteins (UCP) 1/2/3 following bariatric surgery to understand their involvement in enhancing metabolism after surgery.

METHOD

A total of 40 participants were enrolled in this interventional study, 20 with obesity BMI ≥ 35 kg/m² and 20 with BMI ≤ 25 kg/m² . Bariatric surgery (laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass) was performed. The levels of various molecules of interest were analyzed before and after surgery.

RESULTS

Gene expression analysis revealed significantly higher levels of METRNL, UCP1, and UCP3 in individuals with obesity when compared with healthy individuals before surgery (p < 0.05). Gene expression levels of METRNL and UCP2 showed a significant increase after bariatric surgery (p < 0.05). METRNL plasma level was significantly higher in individuals with obesity before surgery (mean [SEM], 55,222.6 [1,421.1] pg/mL, p = 0.0319), as well as at 6 and 12 months (57,537.3 [1,303.9] pg/mL, p = 0.0005; 59,334.9 [1,214.3] pg/mL, p < 0.0001) after surgery.

CONCLUSION

The changes in the levels of various molecules of interest support their possible involvement in the inflammatory and thermogenic responses following bariatric surgery.

Meteorin-like protein (Metrnl): A metabolic syndrome biomarker and an exercise mediator

Metrnl is a secreted protein able to activate different intracellular signaling pathways in adipocytes, macrophages, myocytes and cardiomyocytes with physiological effects of the browning of white adipose tissue (BWT), insulin sensitivity, inflammation inhibition, skeletal muscle regeneration and heart protection. Shown to be regulated by obesity, diabetes, caloric restriction, weight loss and heart diseases, Metrnl is definitely involved in metabolic turbulences, and may play roles in metabolic syndrome (MetS). However, due to the conflicting data yielded, Metrnl is still far from clinical application as a diagnostic and/or a therapeutic agent or even a therapeutic target in MetS-related diseases such as type 2 diabetes (T2D) and obesity. Nevertheless, blood Metrnl levels as well as Metrnl as a cardiokine have been reported to play cardioprotective roles against heart diseases. Considering the established metabolic and anti-inflammatory hallmarks, exercise-induced Metrnl (as a myokine) is regarded as an exercise mediator in improving obesity-induced complications such as insulin resistance, T2D and inflammation. Besides, due to its healing role in muscle damage, Metrnl is also a potential therapeutic candidate to enhance regeneration with ageing or other inflammatory myopathies like Duchenne muscular dystrophy (DMD). Therefore, there are still many exercise-related questions unanswered on Metrnl, such as Metrnl-mediated fat browning in humans, exercise effects on heart Metrnl production and secretion and the effects of other exercise-induced skeletal muscle stressors like hypoxia and oxidative in Metrnl production other than exercise-induced muscle damage.

Subfatin concentration decreases in acute coronary syndrome

Introduction

We investigated the association of serum subfatin concentration and acute myocardial infarction (AMI) in patients with ST-elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI).

Materials and methods

In this study, patients who presented with chest pain (STEMI, NSTEMI, or non-cardiac chest pain) were included, i.e. 49 patients with non-cardiac chest pain (control) and 66 patients hospitalised with AMI. In the AMI group, 35 patients had NSTEMI and 31 had STEMI. Serum subfatin concentrations were determined via enzyme-linked immunosorbent assay (ELISA). Descriptive data on the patients and their comorbidities were recorded, and subfatin concentrations were analysed.

Results

Subfatin concentrations were significantly different in the control, STEMI and NSTEMI groups (P = 0.002). In addition, subfatin concentrations were significantly lower in patients in the NSTEMI group than those in the control group (P < 0.001), but there was no significant difference between STEMI and the control group (P = 0.143). The receiver operating characteristic (ROC) analysis performed for differentiating the AMI and control groups found that subfatin had 64% sensitivity and 69% specificity, whereas troponin had 59% sensitivity and 95% specificity. In patients with AMI, the ROC analysis for differentiating NSTEMI from STEMI found that subfatin had 94% sensitivity and 41% specificity, while troponin had 65% sensitivity and 88% specificity.

Conclusions

Subfatin concentrations were lower in patients without STEMI than in patients with STEMI. Subfatin concentration is associated with NSTEMI.

Associations of carotid intima media thickness with gene expression in whole blood and genetically predicted gene expression across 48 tissues

Carotid intima media thickness (cIMT) is a biomarker of subclinical atherosclerosis and a predictor of future cardiovascular events. Identifying associations between gene expression levels and cIMT may provide insight to atherosclerosis etiology. Here, we use two approaches to identify associations between mRNA levels and cIMT: differential gene expression analysis in whole blood and S-PrediXcan. We used microarrays to measure genome-wide whole blood mRNA levels of 5647 European individuals from four studies. We examined the association of mRNA levels with cIMT adjusted for various potential confounders. Significant associations were tested for replication in three studies totaling 3943 participants. Next, we applied S-PrediXcan to summary statistics from a cIMT genome-wide association study (GWAS) of 71 128 individuals to estimate the association between genetically determined mRNA levels and cIMT and replicated these analyses using S-PrediXcan on an independent GWAS on cIMT that included 22 179 individuals from the UK Biobank. mRNA levels of TNFAIP3, CEBPD and METRNL were inversely associated with cIMT, but these associations were not significant in the replication analysis. S-PrediXcan identified associations between cIMT and genetically determined mRNA levels for 36 genes, of which six were significant in the replication analysis, including TLN2, which had not been previously reported for cIMT. There was weak correlation between our results using differential gene expression analysis and S-PrediXcan. Differential expression analysis and S-PrediXcan represent complementary approaches for the discovery of associations between phenotypes and gene expression. Using these approaches, we prioritize TNFAIP3, CEBPD, METRNL and TLN2 as new candidate genes whose differential expression might modulate cIMT.

Serum Meteorin-like is associated with weight loss in the elderly patients with chronic heart failure

BACKGROUND

Unintentional weight loss (cachexia) has been associated with poor outcomes in chronic heart failure (CHF). Meteorin-like (Metrnl) is a novel myokine with protective effects on cardiovascular diseases. However, the change of Metrnl concentrations and its role in elderly patients with CHF remains unclear. The aim of this study was to evaluate the association of serum Metrnl with weight loss and outcomes in elderly patients with CHF.

METHODS

A total of 931 consecutive elderly patients (aged 60 years and older) with CHF and 135 age-matched and sex-matched control subjects were enrolled. Serum Metrnl concentration was measured by enzyme-linked immunosorbent assay. Body weight was measured at baseline and 12 months.

RESULTS

Median of serum Metrnl levels was lower in CHF patients when compared with controls [201.31 (184.95-261.16) pg/mL vs. 168.68 (103.15-197.54) pg/mL, P < 0.001]. Patients with the lowest levels of Metrnl had higher N-terminal pro brain natriuretic peptide (NT-proBNP) levels but lower left ventricular eject fraction (LVEF) and estimated glomerular filtration rate (P < 0.001). Lower serum Metrnl was associated with a higher risk of >5% weight loss from baseline to 12 months [odds ratio = 6.13, 95% confidence interval (CI) = 2.57-14.62 per log decrease; P < 0.001]. Serum Metrnl levels were decreased as LVEF decreased (P < 0.001) and were positively correlated with LVEF (r = 0.267, P < 0.001) but negatively correlated with NT-proBNP levels (r = -0.257, P < 0.001). Cox regression analysis suggested that lower serum Metrnl was associated with higher cardiovascular mortality [hazard ratio (HR) = 6.71, 95% CI = 3.41-13.18 per log decrease; P < 0.001], CHF rehospitalization (HR = 3.07, 95% CI = 1.82-5.17 per log decrease; P < 0.001), and the combined major adverse cardiac event(s) (MACEs) (HR = 5.38, 95% CI = 3.51-8.25 per log decrease; P < 0.001). The Kaplan-Meier survival curves showed that low concentration of Metrnl was a prognostic indicator of MACEs in patients with CHF.

CONCLUSIONS

Our study suggests that lower serum Metrnl level is correlated with weight loss and the severity of cardiac dysfunction in elderly patients with CHF.

Serum Metrnl levels are decreased in subjects with overweight or obesity and are independently associated with adverse lipid profile

BACKGROUND

Meteorin-like (Metrnl), a novel adipokine, is highly expressed in adipose tissue and has a beneficial effect on energy metabolism. However, data on circulating Metrnl levels in obesity are scarce and inconsistent. This study aimed to evaluate the serum levels of Metrnl in adults with obesity and its association with glucose and lipid metabolism.

METHODS

182 subjects were included in the cross-sectional study. The participants were divided into three groups according to BMI: normal (n = 95), overweight (n = 46), and obesity (n = 41). Serum Metrnl concentrations were measured by enzyme-linked immunosorbent assay.

RESULTS

Serum Metrnl levels in overweight or obese subjects were significantly lower than in the normal group. Circulating Metrnl levels were negatively correlated with TG, TC, LDL-C, and sdLDL and positively correlated with HDL-C before and after adjusting for age, sex, BMI, diabetes, HOMA-IR, and eGFR (all P < 0.05). Furthermore, logistic regression analysis indicated that compared with the highest tertile, the lowest tertile of Metrnl levels were significantly associated with the presence of hyper-TG, hyper-TC, and Hyper-LDL after full adjustment (all P for trend < 0.05).

CONCLUSIONS

Serum Metrnl levels were reduced in individuals with overweight or obesity and were independently associated with adverse lipid profile, suggesting that modifying circulating Metrnl levels may serve as a potential therapeutic target for atherogenic dyslipidemia.

New Discovered Adipokines Associated with the Pathogenesis of Obesity and Type 2 Diabetes

Obesity is defined as abnormal or excessive accumulation of adipose tissue, closely associated with the increased risk of various comorbidities, especially type 2 diabetes mellitus (T2DM). Adipose tissue is a complex structure responsible for not only fat storage but also releasing adipokines which may play roles in the pathogenesis and could be developed into biomarkers for diagnosis, treatment and prognosis of obesity-related metabolic diseases. This review aims to summarize several adipokines discovered recently that have promising functions in obesity and T2DM. Among them, the levels of FSTL1, WISP1 and Asprosin in subjects with obesity or diabetes are commonly higher than in normal controls, suggesting that they may be pathogenic. Inversely, SFRP5, Metrnl, NRG4 and FAM19A5 may serve as the protective factors.

Hepatic Meteorin-like and Krüppel-like Factor 3 are Associated with Weight Loss and Liver Injury

OBJECTIVE

Laparoscopic adjustable gastric banding (LAGB) was found to be effective in reducing body weight and improving insulin resistance in patients with obesity and non-alcoholic fatty liver disease (NAFLD). The adipokine/myokine meteorin-like (METNRL) is an important regulator of whole-body energy expenditure. Krüppel-like factor 3 (KLF3), a regulator of METRNL expression in eosinophils, inhibits the beiging of adipose tissue in mice and therefore regulates adipose tissue development.

METHODS

Thirty-three obese patients undergoing LAGB were included in the study. The hepatic and adipose tissue expression of METNRL and KLF3 was determined before (t0) and 6 months after (t6) LABG. The human liver cancer cell line (HepG2) was stimulated with cytokines and fatty acids and METNRL and KLF3 expressions were analyzed.

RESULTS

LAGB-associated weight loss was correlated with decreased hepatic METNRL expression. The expression of METNRL and KLF3 in hepatic-and adipose tissues correlated before and after LAGB. Individuals with augmented LAGB-induced weight loss (>20 kg) showed lower hepatic METNRL and KLF3 expression before and after LAGB than patients with <20 kg weight loss. METNRL and KLF3 levels were higher in patients with higher NAFLD activity scores. HepG2 stimulation with interleukin-1β, tumor necrosis factor-α, palmitic acid but not interleukin-6, oleic acid, or lipopolysaccharide, induced the expression of one or both investigated adipokines.

CONCLUSIONS

The novel description of METRNL and KLF3 as hepatokines could pave the way to target their production and/or signaling in obesity, NAFLD, and related disorders. Both proteins may act as possible biomarkers to estimate weight loss after bariatric surgery.

Meteorin-Like Ameliorates β Cell Function by Inhibiting β Cell Apoptosis of and Promoting β Cell Proliferation via Activating the WNT/β-Catenin Pathway

Meteorin-like (Metrnl) is a newly discovered myokine. Plasma Metrnl is decreased in subjects with newly diagnosed type 2 diabetes (T2D) and correlated with insulin resistance. This study aims to determine the effects of Metrnl on the apoptosis and proliferation of β cell. Mouse insulinoma MIN6 cells were divided into six groups: normal control, low glucose, high glucose, Vehicle, Metrnl, and Dickkopf 1 (DKK1) groups. MIN6 cells in Metrnl group were transfected with recombinant pCDH-Metrnl vector. WNT/β-catenin pathway was inhibited using DKK1. Then the apoptosis of MIN6 cells was detected using flow cytometry and TUNEL labeling. Immunofluorescence of Ki67 or Edu-594 was used to determine the β cell proliferation. db/db mice were confirmed as T2D group. Lentivirus-Metrnl was injected from the caudal vein of db/db mice once every two weeks for two times. High glucose induced the apoptosis of MIN6 cells and elevated expression of caspase 3. In addition, high glucose resulted in reduced β cell proliferation, cell viability, insulin secretion as well as decreased expression of β-catenin and TCF4. Metrnl ameliorated the above effects of high glucose. And the protecting role of Metrnl was inhibited by DKK1. T2D mice showed higher body weight and blood glucose compared with the controls. The β cell apoptosis was increased while the β cell proliferation and WNT/β-catenin pathway were inhibited in T2D mice. Metrnl treatment partly reversed the above changes in T2D mice. Metrnl ameliorates β cell function by inhibiting β cell apoptosis of and promoting β cell proliferation via activating the WNT/β-catenin pathway.

Myokine-mediated exercise effects: the role of myokine meteorin-like hormone (Metrnl)

Meterorin-like hormone (Metrnl), as a novel secreted factor, has been shown to be involved in physiological and pathophysiological processes. The behaviour of Metrnl in metabolic conditions like type 2 diabetes is conflicting. Metrnl-mediated (treatment with Metrnl) auto/paracrine actions in skeletal muscle are glucose uptake, fat oxidation and muscle regeneration. Exercise-induced Metrnl actions are increased fat oxidation in both skeletal muscle and adipose tissue, the control of inflammation in adipose tissue (metainflammation), and the regulation of muscle regeneration. Based on the current knowledge, Metrnl as a myokine can establish the muscle-fat crosstalk; however, the ability of Metrnl as a myokine to create other crosstalks remains unclear yet. Additionally, given the considerable anti-inflammatory roles of Metrnl in muscle regeneration, it could be a potential therapeutic candidate for muscle-related inflammatory diseases and ageing skeletal muscle which need to be addressed in the future studies.

Involvement of the secreted protein Metrnl in human diseases

Metrnl, a secreted protein expressed in white adipose tissue, has been identified as a novel adipokine. It is also highly expressed in barrier tissues, including the skin, intestinal and respiratory tract epithelium in both mice and humans. Research shows that its expression is upregulated by inflammation, chronic high-fat diets, exercise, cold exposure, etc., and it plays important roles in promoting neurite extension, enhancing white fat browning, improving insulin sensitivity, modulating lipid metabolism and regulating inflammatory response, the latter implying Metrnl is a new cytokine. These studies suggest that Metrnl could be a promising biomarker and a potential therapeutic target for the related diseases. For proving this, clinical studies need to be performed to bridge the gap between bench and bedside. In this paper, we summarize the progress in recent clinical research on Metrnl. Most of these clinical studies are designed to confirm the relationship between circulating Metrnl and metabolic or cardiovascular disease (type 2 diabetes and coronary heart disease), or immune inflammation-related diseases, such as colitis, psoriasis and arthritis. Although blood Metrnl seems to fluctuate and are affected by many factors, such as drugs, physical exercise, and cold exposure, these clinical studies provide reliable clues that Metrnl is associated with coronary heart disease, inflammation-related diseases, etc. Nevertheless, the roles of Metrnl in some diseases such as nervous system diseases remain unclear, and its putative involvement should be further clarified. These studies could promote the application of Metrnl in clinic as a new therapeutic target.

Potential emerging roles of the novel adipokines adipolin/CTRP12 and meteorin-like/METRNL in obesity-osteoarthritis interplay

BACKGROUND

Several insights into obesity-osteoarthritis (OA) relationship have been recently highlighted. Adipolin and metrnl are new adipokines also secreted by chondrocytes. However, their role in OA, and obesity-OA interplay hasn't been elucidated. Therefore, this study was designed to investigate the circulating as well as synovial fluid (SF) levels of adipolin and metrnl in osteoarthritic-patients compared to non-osteoarthritic subjects, and to study their association with OA-severity, dyslipidemia and insulin resistance (IR).

METHODS

Patients with osteoarthritis and obesity (n = 30), and subjects with obesity not suffering OA (n = 25) were enrolled in the current study. Circulating and SF-levels of adipolin, metrnl, and insulin, as well as SF-levels of matrix-metalloproteinase-13 (MMP-13) were measured by ELISA. Knee-radiographs using X-ray were done to determine OA-severity, and investigate its association with adipokines' levels.

RESULTS

Serum and SF-adipolin levels showed tendency to be lower in OA-patients compared to non-OA-subjects; serum: 0.64 [0.45-0.85] and 0.73 [0.62-0.78] ng/ml, p = 0.174, and SF: 0.53 [0.34-0.69] and 0.63 [0.44-0.74] ng/ml, p = 0.353, respectively. Additionally, serum adipolin showed negative-association with SF-MMP-13. However, when stratifying OA-patients into various severity grades, serum adipolin levels did not show a significant difference between them. Regarding serum metrnl, it was significantly lower in OA-patients compared to non-OA-subjects; 19.68 [10.40-53.40] and 48.83 [20.80-86.60] pg/ml, respectively, p = 0.018. Surprisingly, SF-metrnl levels were higher in OA-patients compared to non-OA-subjects; 912 [367-1524] and 315 [125-484] pg/ml, respectively, p = 0.007. SF-metrnl showed positive-association with insulin resistance, and negative-association with SF-MMP-13. Moreover, higher serum metrnl levels were found to be slightly associated with lower likelihood of OA in subjects with obesity; OR = 0.978, CI (0.960- 0.996), p = 0.02, and its levels were also found to be relatively lower in grade-4 compared to the less severe OAgrades.

CONCLUSIONS

Metrnl, and to a lesser extent adipolin seem to be interrelated with OA. Different in-context regulatory mechanisms for metrnl production from various tissues are strongly suggested. Importantly, the findings of the current study shed lights on metrnl as a potential novel mediator and therapeutic target to consider in obesity-OA interplay.

The effect of diclofenac sodium intoxication on the cardiovascular system in rats

OBJECTIVES

Diclofenac sodium (DS) is a widely used nonsteroidal anti-inflammatory drug. Although its high doses are known to cause toxic effects in many tissues including liver and kidney, the effects on the cardiovascular system (CVS) have not been fully elucidated yet. Therefore, this study aimed to investigate the effect of DS on CVS.

METHODS

The Control group did not receive medication; however, a single dose of 240 mg/kg DS was administered orally to the DS group. Electrocardiography (ECG) measurements were performed in all animals before (0thhour) and after (1st,6th,12th,24thhour) intoxication. After 24 h, All animals were sacrificed. Biochemical (malondialdehyde [MDA], and glutathione (GSH), Apelin, Elabela, Meteorin, Endoglin, Keap1, and Nrf2) and histopathological analyzes were performed on heart tissue samples.

RESULTS

ECG results showed that there was a statistically significant increase in QTc, QRS, and heart rate at the 12th and 24th hours in the DS group. The biochemical analysis showed that GSH, Apelin, Keap1, and NRF2 values decreased significantly while Meteorin and Endoglin levels increased in the DS group. When histopathological results were evaluated, distinct lesions were observed in the DS group.

CONCLUSION

In conclusion, high doses of DS intake can cause adverse effects on and damage to CVS.

Correlation of serum meteorin-like concentrations with diabetic nephropathy

OBJECTIVE

Meteorin-like (Metrnl), a secreted myokine, is induced in white adipose tissue during cold exposure and in muscle after exercise. The present investigation aims to determine the hypothesis that serum Metrnl concentrations are correlated with diabetic nephropathy (DN).

METHODS

The investigation was performed in a population of 221 patients with type 2 diabetes mellitus (T2DM) and 74 healthy subjects. T2DM patients were divided into three groups: normoalbuminuria (n = 100), microalbuminuria (n = 86), and macroalbuminuria (n = 35) subgroups based on urine albumin to creatinine ratio (ACR).

RESULTS

All the three T2DM subgroups showed lower serum Metrnl concentrations compared with the controls. Serum Metrnl concentrations were significantly decreased in T2DM patients with macroalbuminuria group than in the other T2DM subgroups. In addition, T2DM patients with microalbuminuria group had decreased serum Metrnl concentrations compared with those with normoalbuminuria; however, the difference was not significant. Logistic regression analysis demonstrated a correlation between serum Metrnl and a decreased risk of T2DM and DN (OR: 0.954, 95% CI: 0.935-0.973, P < 0.001 and OR: 0.981, 95% CI: 0.971-0.997, P = 0.014, respectively). Simply linear regression analysis indicated a negative association between serum Metrnl and duration of disease, body mass index (BMI), HbA1c, blood urea nitrogen, creatinine, uricacid, ACR, and angiotensin-converting enzyme inhibitor/angiotensin II receptor blockers treatment. BMI, HbA1c, and ACR were still correlated with the serum Metrnl after a multiple linear regression analysis.

CONCLUSION

Serum Metrnl concentrations are inversely correlated with renal function and DN.

Characterization of the serum levels of Meteorin-like in patients with inflammatory bowel disease and its association with inflammatory cytokines

Background

Meteorin-like (Metrnl) is an adipokine with insulin sensitizing and anti-inflammatory properties that has been discovered recently. The relation among Metrnl, Inflammatory Bowel Disease (IBD), and obesity has been unexplored yet.

Methods

The present study was conducted on 54 healthy control, 42 Ulcerative Colitis (UC), and 43 Crohn’s disease (CD) patients who were diagnosed by pathological examination. In all participants, serum levels of adiponectin, Metrnl, interleukin (IL)-6, and Tumor necrosis factor (TNF-α) were measured using ELISA kits.

Results

Metrnl concentration was considerably lower in both UC (85.25 ± 36.55 pg/mL) and CD (76.93 ± 27.92 pg/mL) patients in comparison to control (107.52 ± 35.33 pg/mL). In addition, it was seen that both patient groups have a decreased level of adiponectin compared to the controls. Besides that, the level of IL-6 and TNF-α were significantly greater in the patient groups. Moreover, the result showed that the level of Metrnl is inversely correlated with body mass index (BMI) in the controls and the patients. Metrnl levels are also inversely associated with IL-6, and TNF-α in both of the patient groups.

Conclusions

The current study is the first one reporting the decreased levels of Metrnl in serum among patients with IBD, which is inversely related with BMI, TNF-α, and IL-6. These results suggested a possible relation of Metrnl with the pathogenesis of IBD, particularly through inflammatory process, although further studies are warranted to dissect the possible mechanism.

Adipokines and Inflammation: Focus on Cardiovascular Diseases

It is well established that adipose tissue, apart from its energy storage function, acts as an endocrine organ that produces and secretes a number of bioactive substances, including hormones commonly known as adipokines. Obesity is a major risk factor for the development of cardiovascular diseases, mainly due to a low grade of inflammation and the excessive fat accumulation produced in this state. The adipose tissue dysfunction in obesity leads to an aberrant release of adipokines, some of them with direct cardiovascular and inflammatory regulatory functions. Inflammation is a common link between obesity and cardiovascular diseases, so this review will summarise the role of the main adipokines implicated in the regulation of the inflammatory processes occurring under the scenario of cardiovascular diseases.

Probing the epigenetic signatures in subjects with coronary artery disease

Depletion of S-adenosyl methionine and 5-methyltetrahydrofolate; and elevation of total plasma homocysteine were documented in CAD patients, which might modulate the gene-specific methylation status and alter their expression. In this study, we have aimed to delineate CAD-specific epigenetic signatures by investigating the methylation and expression of 11 candidate genes i.e. ABCG1, LIPC, PLTP, IL-6, TNF-α, CDKN2A, CDKN2B, F2RL3, FGF2, P66 and TGFBR3. The methylation-specific PCR and qRT-PCR were used to assess the methylation status and the expression of candidate genes, respectively. CAD patients showed the upregulation of IL-6, TNF-α, CDKN2A, CDKN2B, F2RL3, FGF2, P66, and TGFBR3. Hypomethylation of CDKN2A loci was shown to increase risk for CAD by 1.79-folds (95% CI 1.22-2.63). Classification and regression tree (CART) model of gene expression showed increased risk for CAD with F2RL3 > 3.4-fold, while demonstrating risk reduction with F2RL3 < 3.4-fold and IL-6 < 7.7-folds. This CAD prediction model showed the excellent sensitivity (0.98, 95% CI 0.88-1.00), specificity (0.91, 95% CI 0.86-0.92), positive predictive value (0.82, 95% CI 0.75-0.84), and negative predictive value (0.99, 95% CI 0.94-1.00) with an overall accuracy of 92.8% (95% CI 87.0-94.1%). Folate and B₁₂ deficiencies were observed in CAD cases, which were shown to contribute to hypomethylation and upregulation of the prime candidate genes i.e. CDKN2A and F2RL3. Early onset diabetes was associated with IL-6 and TNF-α hypomethylation and upregulation of CDKN2A. The expression of F2RL3 and IL-6 (or) hypomethylation status at CDKN2A locus are potential biomarkers in CAD risk prediction. Early epigenetic imprints of CAD were observed in early onset diabetes. Folate and B₁₂ deficiencies are the contributing factors to these changes in CAD-specific epigenetic signatures.

Subfatin and asprosin, two new metabolic players of polycystic ovary syndrome

Asprosin and subfatin are recently discovered two new hormones of adipocyte origin that play a role in the regulation of glucose metabolism. Polycystic ovary syndrome (PCOS) is a gynaecological syndrome presenting with energy turbulence. The aim of this study was to investigate whether asprosin and subfatin play a role in PCOS disease. Thirty participants with a diagnosis of PCOS and thirty control group participants were included in this case-control study. Hormone profiles of the participants (subfatin, asprosin, insulin, prolactin, thyroid-stimulating hormone (TSH), oestradiol (E2), follicle-stimulating hormone (FSH), luteinising hormone (LH), dehydroepiandrosterone sulphate (DHEA-SO₄), lipid profiles [(total testosterone, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride, cholesterol)], fasting blood sugar (FBS) and high-sensitivity C-reactive protein (hs-CRP) values were measured. While the levels of asprosin, LDL and triglyceride, TSH, E2, FSH, LH, DHEA-SO₄ were found to be significantly higher in patients with PCOS compared to controls (p = .005; p = .01), subfatin and HDL levels were found to be low. Significantly decreasing subfatin and increasing asprosin levels in circulation in PCOS may play a role in the etiopathology of this disease and that they may also be new candidate molecules in addition to classical laboratory parameters in the diagnosis and follow-up of PCOS in the future.Impact statementWhat is already known on this subject? The studies investigating the relationship between PCOS and asprosin are contradictory. Although subfatin has been studied in many metabolic diseases, it has not been studied yet whether it is associated with PCOS. Furthermore, whether there is a mutual relationship between subfatin and asprosin in patients with PCOS has not been studied yet.What do the results of this study add? This available data indicates that significantly decreasing subfatin and increasing asprosin levels in the circulation in PCOS may play a role in the etiopathology of this disease.What are the implications of these findings for clinical practice and/or further research? The findings are promising in that decreasing subfatin and increasing asprosin levels will shed new light on reproductive endocrinology changes caused by PCOS and may help to clarify the pathophysiology of PCOS. Furthermore, in our study, the asprosin/subfatin ratio was above three in PCOS disease. This ratio reported here is anticipated to contribute to the course or follow-up of the disease in the future. Also, subfatin has been investigated here for the first time, may also be a new candidate molecule in addition to classical laboratory parameters in the diagnosis and follow-up of PCOS.

Meteorin-Like (METRNL) Attenuates Myocardial Ischemia/Reperfusion Injury-Induced Cardiomyocytes Apoptosis by Alleviating Endoplasmic Reticulum Stress via Activation of AMPK-PAK2 Signaling in H9C2 Cells

BACKGROUND Myocardial ischemia mediates the progression of multiple cardiovascular diseases and leads to serious damage to the morphology, function, and metabolism of cardiomyocytes. The serum level of the hormone Meteorin-like (METRNL) was lower in patients with coronary artery disease and was negatively correlated with inflammatory cytokines. The aim of the present study was to determine the relationship between METRNL and myocardial ischemia/reperfusion (MI/R) injury, and investigate the molecular mechanisms implicated the pathogenesis of myocardial ischemia. MATERIAL AND METHODS In the present study, H9C2 cells underwent oxygen-glucose deprivation and reperfusion (OGD/R) treatment to establish a MI/R cell model. Quantitative real-time polymerase chain reaction was performed to analyze the expression of target gene. Western blot was used to evaluate the protein expression. Cell Counting Kit-8 assay was employed to detect the cell viability. Enzyme-linked immunosorbent assay was carried out to determine the levels of inflammatory cytokines. Finally, flow cytometry and TUNEL staining were used to detect the apoptotic levels of cardiomyocytes. RESULTS The results showed that the expression of METRNL was downregulated in H9C2 cells during OGD/R. Interestingly, METRNL overexpression inhibited the inflammation, apoptosis and endoplasmic reticulum stress in H9C2 cells during OGD/R, which were totally reversed by PAK2 silencing. In addition, METRNL overexpression induced activation of AMPK-PAK2 signaling cascade. CONCLUSIONS METRNL attenuates MI/R injury-induced cardiomyocytes apoptosis by alleviating endoplasmic reticulum stress via activation of AMPK-PAK2 signaling in H9C2 cells. Our findings support that METRNL might be a promising target for treatment of myocardial ischemia in the future.

Circulating levels of Meteorin-like protein in polycystic ovary syndrome: A case-control study

Patients diagnosed with polycystic ovary syndrome (PCOS) are at high risk of developing a myriad of endocrinologic and metabolic derailments. Moreover, PCOS is a leading cause of habitual abortion, also known as recurrent pregnancy loss (RPL). Meteorin-like protein (Metrnl) is a newly discovered adipokine with the potential to counteract the metaflammation. This study aimed at determining the associations of serum Metrnl levels with homocysteine, hs-CRP, and some components of metabolic syndrome in PCOS-RPL and infertile PCOS patients.This case-control study was conducted in 120 PCOS patients (60 PCOS-RPL and 60 infertile) and 60 control. Serum hs-CRP and homocysteine were assessed using commercial kits, while adiponectin, Metrnl, FSH, LH, free testosterone and insulin levels were analyzed using ELISA technique. Serum Metrnl levels were found to be lower in PCOS patients when compared to controls (67.98 ± 26.66 vs. 96.47 ± 28.72 pg/mL, P <0.001)). Furthermore, serum adiponectin levels were lower, while free testosterone, fasting insulin, HOMA-IR, homocysteine, and hs-CRP were significantly higher in PCOS group compared to controls. Moreover, serum Metrnl correlated with BMI, adiponectin, and homocysteine in controls, and inversely correlated with FBG, fasting insulin, and HOMA-IR in PCOS group and subgroups. Besides, it inversely correlated with hs-CRP in control, and PCOS group and subgroups. These findings revealed a possible role of Metrnl in the pathogenesis of PCOS and RPL. Nevertheless, there is a necessity for future studies to prove this concept.

Maternal and umbilical cord blood subfatin and spexin levels in patients with gestational diabetes mellitus

Subfatin and spexin are two novel adipokines implicated in glucose homeostasis. This study was designed to investigate changes in blood subfatin and spexin levels during gestational diabetes mellitus (GDM) and childbirth, and define the mechanisms of these hormones in the physiopathology of GDM. A total of 60 pregnant women, comprising 30 diagnosed with GDM and 30 with normal gestation, were included in the study. The diagnosis of GDM was made through a 75-g oral glucose tolerance test (OGTT) administered between 24 and 28 weeks of pregnancy. The amounts of subfatin, spexin, and insulin were measured in blood samples by enzyme-linked immunosorbent assays; lipid profiles, glucose, and other biochemical parameters were measured by using an autoanalyzer. Levels of subfatin and spexin were significantly higher in blood samples drawn at baseline (before OGTT) in mothers with GDM compared to those with normal gestation. Similar observations were made in maternal and cord blood sampled at the end of pregnancy. However, at delivery, the increase in subfatin and spexin concentrations observed at baseline was abrogated in both groups of pregnant women, although levels in mothers with GDM were comparatively higher. These results show that levels of subfatin and spexin increased because of GDM and suggest that these hormones could be potential biomarkers for the diagnosis and management of GDM.

Myokines in skeletal muscle physiology and metabolism: Recent advances and future perspectives

Myokines are molecules produced and secreted by skeletal muscle to act in an auto-, para- and endocrine manner to alter physiological function of target tissues. The growing number of effects of myokines on metabolism of distant tissues provides a compelling case for crosstalk between skeletal muscle and other tissues and organs to regulate metabolic homoeostasis. In this review, we summarize and discuss the current knowledge regarding the impact on metabolism of several canonical and recently identified myokines. We focus specifically on myostatin, β-aminoisobutyric acid, interleukin-15, meteorin-like and myonectin, and discuss how these myokines are induced and regulated as well as their overall function. We also review how these myokines may serve as potential prognostic biomarkers that reflect whole-body metabolism and how they may be attractive therapeutic targets for treating muscle and metabolic diseases.

Is Metrnl an Adipokine İnvolved in the Anti-inflammatory Response to Acute Exacerbations of COPD?

PURPOSE

Chronic obstructive pulmonary disease (COPD) is a common lung disease characterized by airflow limitation and systemic inflammation. Recently, there has been growing interest in adipose tissue-mediated inflammation in the pathogenesis of COPD. The aim of our study was to determine the relationships between a new adipocytokine, meteorin-like protein (Metrnl), and acute exacerbations of COPD, smoking, and comorbidities.

MATERIALS AND METHODS

The study included 313 patients aged 40-65 years in four groups: Group 1: ex-smokers (≥ 20 pack-years) with COPD hospitalized for COPD exacerbation (n = 133), Group 2: current-smokers (≥ 20 pack-years) without COPD (n = 60), Group 3: ex-smokers (≥ 20 pack-years) without COPD (n = 60), and Group 4: never-smokers without COPD (n = 60). Peripheral venous blood samples (5 cc) were collected from all participants. Plasma Metrnl levels were measured using commercial enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

Mean Metrnl levels were 28.45 ± 11.27 ng/ml in Group 1, 24.34 ± 4.38 ng/ml in Group 2, 18.84 ± 3.8 ng/ml in Group 3, and 19.44 ± 3.92 ng/ml in Group 4. Group 1 had significantly higher mean Metrnl level compared to the other groups (p = 0.006, p = 0.001, p = 0.001). Metrnl level was also significantly higher in Group 2 when compared with Groups 3 and 4 (p = 0.001, p = 0.005). Group 1 patients with diabetes mellitus and coronary artery disease showed significantly lower Metrnl levels compared to other patients in the group (p = 0.001, p = 0.001).

CONCLUSION

The high Metrnl level in COPD exacerbations and active smoking may be important in balancing the inflammatory response. However, plasma Metrnl levels were found to be lower in COPD patients with comorbidities.

Serum Metrnl Level is Correlated with Insulin Resistance, But Not with β-Cell Function in Type 2 Diabetics

Background

Metrnl is a novel identified adipomyokine which might have therapeutic potential for metabolic and inflammatory diseases, including type 2 diabetes mellitus. We aimed to explore the associations of circulating Metrnl level with β-cell function and insulin resistance (IR) and further explore the possible correlation between Metrnl and another adipomyokine named irisin in patients diagnosed type 2 diabetes.

Material/Methods

Our study recruited 59 participants with type 2 diabetes and 30 normal glucose tolerance (NGT) participants. We used enzyme-linked immunosorbent assay (ELISA) to measure serum levels of Metrnl and irisin. The associations of Metrnl level with indexes of β-cell function and IR and irisin level were analyzed by multiple linear regression analysis or spearman correlation analysis.

Results

Compared with NGT participants, serum Metrnl level was elevated in participants with type 2 diabetes: 210.30 pg/mL (range 105.94–323.91 pg/mL) versus 132.02 pg/mL (range 104.93–195.92 pg/mL). Metrnl level did not show significant correlation with β-cell function-related indicators, but positively correlated with HOMA2-IR and negatively correlated with HOMA2-%S after controlling multiple covariates in participants with type 2 diabetes. Metrnl level was also not associated with obesity-related indicators (body mass index, waist circumference, body fat percentage, and visceral adipose tissue area) in the type 2 diabetes group. In addition, the correlation between Metrnl and irisin level was also not present (r=−0.159, P=0.229) in type 2 diabetes group.

Conclusions

Serum Metrnl level was associated with IR, but not with β-cell function in participants with diagnosed type 2 diabetes.

Maternal obesity and gestational diabetes decrease Metrnl concentrations in cord plasma

OBJECTIVE

To determine the effect of preexisting maternal obesity and gestational diabetes mellitus (GDM) on the circulating levels of Metrnl in cord and maternal plasma.

DESIGN

Metrnl levels were measured on maternal and cord plasma from women with normal glucose tolerance (NGT) (19 non-obese and 20 obese), GDM controlled by diet (18 non-obese and 17 obese) and GDM controlled by insulin (19 non-obese and 18 obese) at the time of term elective cesarean section. Metrnl concentrations were determined by enzyme-linked immunoassay. Correlations of Metrnl levels with anthropometric parameters and laboratory measurements were also assessed.

RESULTS

There was no effect of maternal obesity or GDM on maternal plasma Metrnl concentrations. In cord plasma, Metrnl concentrations were significantly lower in NGT obese compared to NGT non-obese women and in non-obese GDM women compared to non-obese NGT women. Significant positive correlations were observed between maternal plasma Metrnl and cord plasma Metrnl. In cord plasma, significant positive correlations were observed between Metrnl levels and GWG and maternal and cord plasma glucose levels at delivery.

CONCLUSIONS

At the time of term cesarean section, preexisting maternal obesity and GDM are associated with lower Metrnl levels in cord plasma. Alterations in cord plasma Metrnl levels may lead to alterations in fetal growth trajectory and be a determinant for metabolic disorders later in life.

Correlation of serum meteorin-like concentration with the presence and severity of obstructive sleep apnoea syndrome

Objective

Inflammatory processes that occur in subjects with obstructive sleep apnoea syndrome may contribute to progressive atherosclerosis and increased cardiovascular and cerebrovascular morbidity. Meteorin-like protein, which is also known as subfatin, is transcribed similarly to meteorin protein. Meteorin-like alleviates skeletal muscle inflammation. We aimed to investigate the serum meteorin-like status of obstructive sleep apnoea syndrome subjects and determine the potential link between serum meteorin-like concentration with the presence and severity of obstructive sleep apnoea syndrome.

Methods

The obstructive sleep apnoea syndrome group was composed of 207 obstructive sleep apnoea syndrome subjects diagnosed via polysomnography. A total of 106 healthy volunteers without clinical symptoms of obstructive sleep apnoea syndrome were recruited as the control group. Blood samples were obtained from all subjects to evaluate the serum meteorin-like concentrations via enzyme-linked immunosorbent assay method.

Results

Decreased serum meteorin-like concentration was found in obstructive sleep apnoea syndrome subjects compared with the controls. Serum meteorin-like concentration was associated with a reduced OR for having obstructive sleep apnoea syndrome (OR 0.97, 95% CI 0.961 to 0.98; P < 0.001). Severe obstructive sleep apnoea syndrome subjects showed significantly lower meteorin-like concentration compared with mild and moderate cases. Moderate subjects exhibited decreased serum meteorin-like concentration compared with mild cases. Pearson correlation analysis revealed that serum meteorin-like concentration was negatively correlated with obstructive sleep apnoea syndrome severity. Serum meteorin-like concentration negatively correlated with body mass index, low-density lipoprotein cholesterol, apnoea–hypopnea index, number of arousals, hypopnoea and apnoea in subjects with obstructive sleep apnoea syndrome.

Conclusion

Serum meteorin-like concentration is inversely correlated with the presence and severity of obstructive sleep apnoea syndrome.

Association of low serum Meteorin like (Metrnl) concentrations with worsening of glucose tolerance, impaired endothelial function and atherosclerosis

OBJECTIVE

Meteorin-like (Metrnl) is a novel secreted protein that has a beneficial effect on glucose homeostasis with anti-inflammatory properties. Our goal is to determine whether low serum Metrnl levels are associated with worsening of glucose tolerance, impaired endothelial function, and atherosclerosis.

METHODS

This study included 260 adults, 89 of whom had normal oral glucose tolerance (nOGT), 77 with glucose tolerance impairment (GTI) and 94 with type 2 diabetes (T2DM). Insulin resistance was assessed by evaluating the homeostasis model assessment of insulin resistance (HOMA-IR). Serum Metrnl level, proinflammatory, biochemical, endothelial and atherosclerosis parameters were measured.

RESULTS

Serum Metrnl levels decreased significantly in patients with T2DM versus subjects with nOGT (P < 0.001). Metrnl levels were negatively correlated with fasting blood glucose, 2-h postload glucose (2 h-PLG), fasting insulin, HOMA-IR, HbA1c, high-sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), Carotid intima media thickness (CIMT), brachial-ankle pulse wave velocity (baPWV), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin. High serum Metrnl level was significantly correlated with reduced risk of T2DM as revealed by multivariate logistic regression analysis after control of potential risk factors for diabetes. Furthermore, the association remains significant after further adjustment for IL-6, TNF-α, hs-CRP, CIMT, baPWV, ICAM-1, VCAM-1 and E-selectin.

CONCLUSIONS

Low Serum Metrnl may be associated with worsening of glucose tolerance, impaired endothelial function and atherosclerosis. It may also be considered a possible surrogate marker of endothelial dysfunction, and atherosclerosis and an independent risk factor of T2DM.