Circulating levels of CTRP3 in patients with type 2 diabetes mellitus compared to controls: A systematic review and meta-analysis

Decreased circulating CTRP3 levels in acute and chronic cardiovascular patients

C1q/TNF-related protein 3 (CTRP3) represents an adipokine with various metabolic and immune-regulatory functions. While circulating CTRP3 has been proposed as a potential biomarker for cardiovascular disease (CVD), current data on CTRP3 regarding coronary artery disease (CAD) remains partially contradictory. This study aimed to investigate CTRP3 levels in chronic and acute settings such as chronic coronary syndrome (CCS) and acute coronary syndrome (ACS). A total of 206 patients were classified into three groups: CCS (n = 64), ACS having a first acute event (ACS-1, n = 75), and ACS having a recurrent acute event (ACS-2, n = 67). The control group consisted of 49 healthy individuals. ELISA measurement in peripheral blood revealed decreased CTRP3 levels in all patient groups (p < 0.001) without significant differences between the groups. This effect was exclusively observed in male patients. Females generally exhibited significantly higher CTRP3 plasma levels than males. ROC curve analysis in male patients revealed a valuable predictive potency of plasma CTRP3 in order to identify CAD patients, with a proposed cut-off value of 51.25 ng/mL. The sensitivity and specificity of prediction by CTRP3 were congruent for the subgroups of CCS, ACS-1, and ACS-2 patients. Regulation of circulating CTRP3 levels in murine models of cardiovascular pathophysiology was found to be partly opposite to the clinical findings, with male mice exhibiting higher circulating CTRP3 levels than females. We conclude that circulating CTRP3 levels are decreased in both male CCS and ACS patients. Therefore, CTRP3 might be useful as a biomarker for CAD but not for distinguishing an acute from a chronic setting. KEY MESSAGES: CTRP3 levels were found to be decreased in both male CCS and ACS patients compared to healthy controls. Plasma CTRP3 has a valuable predictive potency in order to identify CAD patients among men and is therefore proposed as a biomarker for CAD but not for distinguishing between acute and chronic settings. Regulation of circulating CTRP3 levels in murine models of cardiovascular pathophysiology was found to be partly opposite to the clinical findings in men.

Obesity, chronic kidney disease progression and the role of the adipokine C1q/TNF related protein-3

INTRODUCTION AND AIMS

Obesity is a risk factor for incident chronic kidney disease (CKD). C1q/TNF related protein 3 (CTRP3) is an adipokine with multiple effects and may modulate the association between obesity and vascular diseases. The aim of the study is to explore potential links between obesity, CTRP3 levels and CKD progression.

METHODS

Patients with stage 3 and 4 CKD without previous cardiovascular events were enrolled and divided into groups according to body mass index (BMI) and sex. Demographic, clinical, analytical data and CTRP3 levels were collected at baseline. During follow-up, renal events (defined as dialysis initiation, serum creatinine doubling or a 50% decrease in estimated glomerular filtration rate were registered).

RESULTS

81 patients were enrolled. 27 were obese and 54 non-obese. Baseline CTRP3 was similar between both groups (90.1±23.8 vs 84.5±6.2; p=0.28). Of the sum, 54 were men and 27 women, with higher CTRP3 in women (81.4±24.7 vs 106±24.7;p<0.01). During a mean follow-up of 68 months, 15 patients had a renal event. Patients in the higher CTRP3 tertile had less events but without statistical significance (p=0.07). Obese patients in the higher CTRP3 tertile significantly had less renal events (p=0.049). By multiple regression analysis CTRP3 levels could not predict renal events (HR 0.98; CI95% 0.96-1.06).

CONCLUSIONS

CTRP3 levels are higher in woman than men in patients with CKD, with similar levels between obese and non obese. Higher CTRP3 levels at baseline were associated with better renal outcomes in obese patients.

The Role of Adipokines in the Pathogenesis of Psoriasis

Psoriasis is a chronic and immune-mediated skin condition characterized by pro-inflammatory cytokines and keratinocyte hyperproliferation. Dendritic cells, T lymphocytes, and keratinocytes represent the main cell subtypes involved in the pathogenesis of psoriasis, while the interleukin-23 (IL-23)/IL-17 pathway enhances the disease progression. Human adipose tissue is an endocrine organ, which secretes multiple proteins, known as adipokines, such as adiponectin, leptin, visfatin, or resistin. Current evidence highlights the immunomodulatory roles of adipokines, which may contribute to the progression or suppression of psoriasis. A better understanding of the complexity of psoriasis pathophysiology linked with adipokines could result in developing novel diagnostic or therapeutic strategies. This review aims to present the pathogenesis of psoriasis and the roles of adipokines in this process.

Clinical Diagnostic Values of C1q/TNF-Related Protein-3 for Polycystic Ovary Syndrome Women with Insulin Resistance

Polycystic ovary syndrome (PCOS) is the most common disease caused by complex endocrine and metabolic abnormalities in women. Insulin resistance is considered an important pathophysiological factor in the pathogenesis of PCOS. Here we investigated the clinical values of C1q/TNF-related protein-3 (CTRP3) as predictive factor for insulin resistance. Our study included 200 patients with PCOS, among which 108 had insulin resistance. Serum CTRP3 levels were measured using enzyme-linked immunosorbent assay. Predictive values of CTRP3 for insulin resistance was analyzed using receiver operating characteristic (ROC) analysis. Correlations of CTRP3 to insulin levels, obesity measurements and blood lipid levels were determined using Spearman's correlation analysis. Our data suggested that PCOS patients with insulin resistance had a higher obesity, lower high-density lipoprotein cholesterol, higher total cholesterol, higher insulin levels and lower CTRP3 levels. CTRP3 had a high sensitivity (72.22%) and specificity (72.83%). CTRP3 significantly correlated to insulin levels, body mass index, waist-to-hip ratio, high-density lipoprotein, and total cholesterol levels. The predictive value of CTRP3 in PCOS patients with insulin resistance was supported by our data. Our findings suggest that CTRP3 is involved in the pathogenesis and insulin resistance of PCOS, which indicates its value as an indicator for the PCOS diagnosis.

Astragaloside IV Regulates Insulin Resistance and Inflammatory Response of Adipocytes via Modulating CTRP3 and PI3K/AKT Signaling

INTRODUCTION

Emerging evidence showed that adipocytes are important regulators in controlling insulin resistance in type 2 diabetes mellitus (T2DM). So far, compounds isolated from natural plants have been widely studied for their roles in alleviating T2DM-associated complications. This work evaluated the actions of astragaloside IV (AS-IV) on insulin resistance and inflammatory biomarker expression in adipocytes and explored the potential mechanisms.

METHODS

Glucose consumption of the adipocytes was determined by a glucose assay kit; the mRNA expression levels of glucose transporter type 4 (GLUT-4), interleukin-6 (IL-6), TNF-α and C1q tumor necrosis factor-related protein 3 (CTRP3) were measured by quantitative real-time PCR (qRT-PCR); the protein levels were determined by western blot assay and enzyme-linked immunosorbent assay.

RESULTS

AS-IV concentration-dependently increased glucose consumption in the insulin resistance adipocytes. Further qRT-PCR results showed that AS-IV concentration-dependently reduced adipocyte IL-6 and TNF-α expression. Moreover, GLUT-4 expression in adipocytes was also significantly upregulated by AS-IV. Furthermore, we found that AS-IV concentration-dependently increased CTRP3 expression in adipocytes. CTRP3 silence decreased glucose consumption, upregulated IL-6 and TNF-α expression and downregulated GLUT-4 mRNA expression in 200 µM AS-IV-treated adipocytes. Moreover, AS-IV treatment enhanced the activity of phosphoinositide 3-kinase (PI3K)/AKT signaling in adipocytes, which was markedly attenuated by CTRP3 silencing. Importantly, inhibition of PI3K/AKT signaling also attenuated AS-IV induced an increase in glucose consumption and GLUT-4 expression and a decrease in IL-6 and TNF-α expression of adipocytes.

CONCLUSIONS

Collectively, our data indicated that AS-IV attenuated insulin resistance and inflammation in adipocytes via targeting CTRP3/PI3K/Akt signaling.

Circulating Levels of C1q/TNF-Related Protein 3 (CTRP3) and CTRP9 in Gestational Diabetes and Their Association with Insulin Resistance and Inflammatory Cytokines

Objective

Gestational diabetes mellitus (GDM) is closely related to obesity, adipose tissue, and adipokines. Adiponectin-homologous adipokines with anti-inflammatory properties, including C1q/TNF-related protein 3 (CTRP3) and CTRP9, regulate glucose and lipid metabolism, which was measured in pregnant women with GDM with the aim to assess their circulating levels and their relation with inflammatory cytokines and other biochemical data.

Methods

Serum levels of CTRP3, CTRP9, adiponectin, tumor necrosis factor (TNF)-α, and interleukin (IL)-6 were measured in 43 subjects with GDM and 42 healthy controls by enzyme-linked immunosorbent assay.

Results

Serum levels of adiponectin and CTRP3 were lower in GDM subjects than in controls, whereas CTRP9, TNF-α, and IL-6 showed higher concentrations in subjects with GDM than in controls. In the subjects with GDM, there was a significant association of CTRP3 with homeostasis model assessment of insulin resistance (HOMA-IR), body mass index, and triglycerides, whereas CTRP9 is associated with TNF-α and HOMA-IR.

Conclusion

The differences in the assessed levels of CTRP3 and CTRP9 suggest a possible relation with the pathogenesis of GDM, in particular insulin resistance, which showed significant association with both adipokines.

C1QTNF3 is Upregulated During Subcutaneous Adipose Tissue Remodeling and Stimulates Macrophage Chemotaxis and M1-Like Polarization

The adipose tissue undergoes substantial tissue remodeling during weight gain-induced expansion as well as in response to the mechanical and immunological stresses from a growing tumor. We identified the C1q/TNF-related protein family member C1qtnf3 as one of the most upregulated genes that encode secreted proteins in tumor-associated inguinal adipose tissue - especially in high fat diet-induced obese mice that displayed 3-fold larger tumors than their lean controls. Interestingly, inguinal adipose tissue C1qtnf3 was co-regulated with several macrophage markers and chemokines and was primarily expressed in fibroblasts while only low levels were detected in adipocytes and macrophages. Administration of C1QTNF3 neutralizing antibodies inhibited macrophage accumulation in tumor-associated inguinal adipose tissue while tumor growth was unaffected. In line with this finding, C1QTNF3 exerted chemotactic actions on both M1- and M2-polarized macrophages in vitro. Moreover, C1QTNF3 treatment of M2-type macrophages stimulated the ERK and Akt pathway associated with increased M1-like polarization as judged by increased expression of M1-macrophage markers, increased production of nitric oxide, reduced oxygen consumption and increased glycolysis. Based on these results, we propose that macrophages are recruited to adipose tissue sites with increased C1QTNF3 production. However, the impact of the immunomodulatory effects of C1QTNF3 in adipose tissue remodeling warrants future investigations.

CTRP3 is a coronary artery calcification biomarker and protects against vascular calcification by inhibiting β-catenin nuclear translocation to prevent vascular smooth muscle cell osteogenic differentiation

BACKGROUND

Coronary artery calcification (CAC) is an important risk factor for cardiovascular events and has been shown to be correlated with serum adiponectin levels. However, it remains unknown whether C1 tumor necrosis factor-related protein 3 (CTRP3) (homologous to adiponectin) is associated with CAC, and whether CTRP3 affects the osteoblastic differentiation of vascular smooth muscle cells. Here, we analyzed the association between CTRP3 expression and CAC.

METHODS

A case-control study was conducted involving 119 patients with coronary heart disease to identify the predictive value of CTRP3 for CAC. Additionally, mouse aortic smooth muscle cells transfected for β-catenin overexpression were subjected to treatment with CTRP3 and the β-catenin inhibitor JW74. The calcium content in smooth muscle cells was determined. Western blotting was performed to measure the expression levels of different osteoblastogenic proteins in vascular smooth muscle cells obtained from different treatment groups.

RESULTS

The serum CTRP3 levels were significantly lower in patients with CAC than in those without CAC, and even lower in patients with both CAC and diabetes mellitus. CTRP3 played roles as a protective factor and potential predictor in CAC. CTRP3 inhibited the osteogenic differentiation of vascular smooth muscle cells induced under high glucose and lipid conditions by inhibiting the nuclear translocation of β-catenin.

CONCLUSIONS

CTRP3 may serve as a valuable screening biomarker and a novel therapeutic target in CAC, particularly in diabetes patients.

Role of the CTRP family in tumor development and progression

C1q tumor necrosis factor-related proteins (CTRPs), which are members of the adipokine superfamily, have gained significant interest in the recent years. CTRPs are homologs of adiponectin with numerous functions and are closely associated with metabolic diseases, such as abnormal glucose and lipid metabolism and diabetes. Previous studies have demonstrated that CTRPs are highly involved in the regulation of numerous physiological and pathological processes, including glycolipid metabolism, protein kinase pathways, cell proliferation, cell apoptosis and inflammation. CTRPs also play important roles in the development and progression of numerous types of tumor, including liver, colon and lung cancers. This observation can be attributed to the fact that diabetes, obesity and insulin resistance are independent risk factors for tumorigenesis. Numerous CTRPs, including CTRP3, CTRP4, CTRP6 and CTRP8, have been reported to be associated with tumor progression by activating multiple signal pathways. CTRPs could therefore be considered as diagnostic markers and therapeutic targets in some cancers. However, the underlying mechanisms of CTRPs in tumorigenesis remain unknown. The present review aimed to determine the roles and underlying mechanisms of CTRPs in tumorigenesis, which may help the development of novel cancer treatments in the future.