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

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/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.

Increased serum IL-41 is associated with disease activity in rheumatoid arthritis

BACKGROUND

Interleukin (IL)-41 is upregulated in the synovial tissue of rheumatoid arthritis (RA) patients, but its serum level has not been reported. The present study aimed to determine IL-41 expression in serum from RA patients and to clarify the relationships between IL-41 and disease-related parameters in RA patients.

METHODS

The study included 46 RA patients and 32 healthy controls (HC). Baseline data were obtained by routine physical examinations and immune-related parameters were measured by an automated chemiluminescent immunoassay analyzer. The correlations between IL-41 and disease activity score in 28 joints (DAS28) and serum clinical data were analyzed using the Pearson correlation test.

RESULTS

Serum IL-41 concentrations were higher in RA patients than in HC. Serum IL-41 was positively correlated with DAS28 based on C-reactive protein (DAS28-CRP), CRP, erythrocyte sedimentation rate (ESR), mean platelet volume (MPV), and CRP-to-albumin ratio (CAR) and negatively correlated with platelet count, while rheumatoid factor was significantly correlated with ESR, CRP, and CAR. Receiver operating characteristic curve analysis showed that IL-41 had diagnostic value for RA, especially when combined with MPV.

CONCLUSIONS

The present findings suggest that IL-41 is increased in the serum of RA patients and may be a potential new diagnostic biomarker for RA.

Plasma Prostaglandin E2 Metabolite Levels Predict Type 2 Diabetes Status and One-Year Therapeutic Response Independent of Clinical Markers of Inflammation

Over half of patients with type 2 diabetes (T2D) are unable to achieve blood glucose targets despite therapeutic compliance, significantly increasing their risk of long-term complications. Discovering ways to identify and properly treat these individuals is a critical problem in the field. The arachidonic acid metabolite, prostaglandin E₂ (PGE₂), has shown great promise as a biomarker of β-cell dysfunction in T2D. PGE₂ synthesis, secretion, and downstream signaling are all upregulated in pancreatic islets isolated from T2D mice and human organ donors. In these islets, preventing β-cell PGE₂ signaling via a prostaglandin EP3 receptor antagonist significantly improves their glucose-stimulated and hormone-potentiated insulin secretion response. In this clinical cohort study, 167 participants, 35 non-diabetic, and 132 with T2D, were recruited from the University of Wisconsin Hospital and Clinics. At enrollment, a standard set of demographic, biometric, and clinical measurements were performed to quantify obesity status and glucose control. C reactive protein was measured to exclude acute inflammation/illness, and white cell count (WBC), erythrocyte sedimentation rate (ESR), and fasting triglycerides were used as markers of systemic inflammation. Finally, a plasma sample for research was used to determine circulating PGE₂ metabolite (PGEM) levels. At baseline, PGEM levels were not correlated with WBC and triglycerides, only weakly correlated with ESR, and were the strongest predictor of T2D disease status. One year after enrollment, blood glucose management was assessed by chart review, with a clinically-relevant change in hemoglobin A1c (HbA1c) defined as ≥0.5%. PGEM levels were strongly predictive of therapeutic response, independent of age, obesity, glucose control, and systemic inflammation at enrollment. Our results provide strong support for future research in this area.

Exploration of meteorin-like peptide (metrnl) predictors in type 2 diabetic patients: the potential role of irisin, and other biochemical parameters

OBJECTIVES

Meteorin-like peptide (Metrnl), the newly discovered adipokines involves in glucose and lipid metabolism and energy homeostasis. The aim of the present study was to explore the potential predictors of Metrnl by emphasizing the Irisin, glycemic indices, and lipid profile biomarkers in type 2 diabetic patients.

METHODS

This cross-sectional study was carried out on 32 obese types 2 diabetic patients, 31 healthy obese, and 30 healthy normal weight people between August 2020 and March 2021. Serum Metrnl and Irisin, fasting blood glucose (FBS), fasting insulin (FI), fasting insulin (FI), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), HbA_1c and eAG levels were measured in a standard manner. To assay insulin resistance and insulin sensitivity, the homeostatic model assessment insulin resistance (HOMA-IR) and quantitative check index (QUICKI) model were used. Quantile regression analysis with the backward elimination method was used to explore predictors. The significant level was defined as p<0.05.

RESULTS

Between variables entered into the model, only the group item showed to be the main predictor of Metrnl in type 2 diabetic patients. Besides, the serum level of Irisin was lower in diabetic patients, and a significant difference was detected between obese diabetic patients and the normal weight group (p=0.024).

CONCLUSIONS

Given the multi-causality of diabetes and also the possible therapeutic role of Metrnl in the management of type 2 diabetic patients' abnormalities, designing future studies are needed to discover other predictors of Metrnl and the related mechanisms of Metrnl in the management of diabetes.

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.

The Role of Exercise in the Interplay between Myokines, Hepatokines, Osteokines, Adipokines, and Modulation of Inflammation for Energy Substrate Redistribution and Fat Mass Loss: A Review

Exercise is an effective strategy for preventing and treating obesity and its related cardiometabolic disorders, resulting in significant loss of body fat mass, white adipose tissue browning, redistribution of energy substrates, optimization of global energy expenditure, enhancement of hypothalamic circuits that control appetite-satiety and energy expenditure, and decreased systemic inflammation and insulin resistance. Novel exercise-inducible soluble factors, including myokines, hepatokines, and osteokines, and immune cytokines and adipokines are hypothesized to play an important role in the body's response to exercise. To our knowledge, no review has provided a comprehensive integrative overview of these novel molecular players and the mechanisms involved in the redistribution of metabolic fuel during and after exercise, the loss of weight and fat mass, and reduced inflammation. In this review, we explain the potential role of these exercise-inducible factors, namely myokines, such as irisin, IL-6, IL-15, METRNL, BAIBA, and myostatin, and hepatokines, in particular selenoprotein P, fetuin A, FGF21, ANGPTL4, and follistatin. We also describe the function of osteokines, specifically osteocalcin, and of adipokines such as leptin, adiponectin, and resistin. We also emphasize an integrative overview of the pleiotropic mechanisms, the metabolic pathways, and the inter-organ crosstalk involved in energy expenditure, fat mass loss, reduced inflammation, and healthy weight induced by exercise.