C1q/TNF-Related Protein-9 (CTRP9) Levels Are Associated With Obesity and Decrease Following Weight Loss Surgery

New Markers for the Assessment of Microvascular Complications in Patients with Metabolic Syndrome

Background: Metabolic syndrome is a complex disorder characterized by the coexistence of multiple risk factors, including dysglycemia, hypertension, dyslipidemia, and visceral obesity. Both metabolic syndrome and diabetes mellitus are closely associated with the onset of microvascular complications such as retinopathy, polyneuropathy, and nephropathy. Methods: This narrative review analyzed 137 studies published up to 2025, retrieved from PubMed and Crossref databases. The objective was to identify and evaluate potential biomarkers that could facilitate the early detection of microvascular complications in patients with metabolic syndrome. Results: Several biomarkers demonstrated a strong correlation with microvascular complications in individuals with metabolic syndrome. These findings suggest their potential role in early diagnosis and risk assessment. Conclusions: The identification of reliable biomarkers may enhance early detection and targeted interventions for microvascular complications in metabolic syndrome. Further research is essential to validate these markers and establish their clinical applicability in routine medical practice.

Mechanisms by which obesity regulates inflammation and anti-tumor immunity in cancer

Obesity is associated with an increased risk for 13 different cancers. The increased risk for cancer in obesity is mediated by obesity-associated changes in the immune system. Obesity has distinct effects on different types of inflammation that are tied to tumorigenesis. For example, obesity promotes chronic inflammation in adipose tissue that is tumor-promoting in peripheral tissues. Conversely, obesity inhibits acute inflammation that rejects tumors. Obesity therefore promotes cancer by differentially regulating chronic versus acute inflammation. Given that obesity is chronic, the initial inflammation in adipose tissue will lead to systemic inflammation that could induce compensatory anti-inflammatory reactions in peripheral tissues to suppress chronic inflammation. The overall effect of obesity in peripheral tissues is therefore dependent on the duration and severity of obesity. Adipose tissue is a complex tissue that is composed of many cell types in addition to adipocytes. Further, adipose tissue cellularity is different at different anatomical sites throughout the body. Consequently, the sensitivity of adipose tissue to obesity is dependent on the anatomical location of the adipose depot. For example, obesity induces more inflammation in visceral than subcutaneous adipose tissue. Based on these studies, the mechanisms by which obesity promotes tumorigenesis are multifactorial and immune cell type-specific. The objective of our paper is to discuss the cellular mechanisms by which obesity promotes tumorigenesis by regulating distinct types of inflammation in adipose tissue and the tumor microenvironment.

CTRP9 alleviates diet induced obesity through increasing lipolysis mediated by enhancing autophagy-initiation complex formation

Recently, emerging evidence has suggested that obesity become a prevalent health threat worldwide. Reportedly, CTRP9 can ameliorate HFD induced obesity. However, the molecular mechanism underlying the role of CTRP9 in obesity remains elusive. In this study, we reported its major function in the regulation of lipolysis. First, we found that the expression of CTRP9 was decreased in mature adipocytes and white adipose tissue of obese mice. Then, we showed that overexpression adipose tissue CTRP9 alleviated diet-induced obesity and adipocytes hypertrophy, improved glucose intolerance and raised energy expenditure. Moreover, CTRP9 increased the lipolysis in vitro and vivo. Additionally, we determined that CTRP9 enhanced autophagy flux in adipocytes. Intriguingly, knock down Beclin1 by SiRNA abolished the effect of CTRP9 on lipolysis. Mechanically, CTRP9 enhanced the expression of SNX26. We demonstrated that SNX26 was a component of the ATG14L-Beclin1-VPS34 complex and enhanced the assembly of the autophagy-initiation complex. Collectively, our results suggested that CTRP9 alleviated diet induced obesity through enhancing lipolysis mediated by autophagy-initiation complex formation.

The Effects of 12 Weeks of Concurrent and Combined Training on Inflammatory Markers, Muscular Performance, and Body Composition in Middle-Aged Overweight and Obese Males

Aim: Previous studies have focused on the order of endurance and resistance training when performing concurrent training (CT). However, no study has compared the effects of combined training with CT orders on inflammatory markers, muscular performance, and body composition in overweight and obese males. Therefore, the purpose of the current study was to compare the effects of 12 weeks of CT and combined training on the aforementioned markers in overweight and obese males. Methods: Sixty middle-aged overweight and obese males (age 51 ± 4 years) were randomly assigned into one of four groups: endurance followed by resistance training (ER; n = 15), resistance followed by endurance training (RE; n = 15), combined resistance and endurance training (COM), or control (CON; n = 15). Anthropometric, body composition, inflammatory marker, and muscular performance measurements were collected at baseline and after 12 weeks. Results: FFM remained unchanged in all three intervention groups (p > 0.05). Reductions in FM in the RE group were significantly greater than in CON (p = 0.038). The increases in serum concentrations of adiponectin in the RE group were significantly greater than in all other groups (p < 0.05). Increased serum concentrations of CTRP3 in all intervention groups were significantly greater than the CON group (p < 0.05); moreover, the increases in the RE group were significantly greater than CON (p < 0.001). Regarding CTRP5, the increase in RE was significantly greater than COM (p = 0.014). The RE group experienced significantly greater increases in CTRP9 than all other groups (p < 0.05), and the decreases in serum concentrations of CRP and TNF-α were significantly greater in the RE group compared to CON and ER (p < 0.05). Vo2max in the ER group was significantly greater than COM (p = 0.009), and all interventions resulted in higher gains compared to CON (p < 0.05). The increases in leg press strength, chest press strength, lower-body power, and upper-body power in the RE group were significantly greater than in the COM group (p < 0.05). In addition, the increases in chest press strength in the ER group were significantly greater than COM (p = 0.023). Conclusions: Regardless of training order, CT improved inflammatory markers, body composition, power, and VO2max. Notably, our analysis indicated significantly greater improvements in adiponectin, CTRP5, CTRP9, CRP, and TNF-α levels when RT preceded ET in CT sessions compared to other exercise training sequences. These findings suggested that the order of exercise training may have a significant impact on the effectiveness of CT on inflammatory markers, which has potential implications for exercise prescription and optimization of health-related training outcomes.

Astaxanthin Supplemented with High-Intensity Functional Training Decreases Adipokines Levels and Cardiovascular Risk Factors in Men with Obesity

The aim of this study was to investigate the effects of 12 weeks of high-intensity training with astaxanthin supplementation on adipokine levels, insulin resistance and lipid profiles in males with obesity. Sixty-eight males with obesity were randomly stratified into four groups of seventeen subjects each: control group (CG), supplement group (SG), training group (TG), and training plus supplement group (TSG). Participants underwent 12 weeks of treatment with astaxanthin or placebo (20 mg/d capsule daily). The training protocol consisted of 36 sessions of high-intensity functional training (HIFT), 60 min/sessions, and three sessions/week. Metabolic profiles, body composition, anthropometrical measurements, cardio-respiratory indices and adipokine [Cq1/TNF-related protein 9 and 2 (CTRP9 and CTRP2) levels, and growth differentiation factors 8 and 15 (GDF8 and GDF15)] were measured. There were significant differences for all indicators between the groups (p < 0.05). Post-hoc analysis indicated that the levels of CTRP9, CTRP2, and GDF8 were different from CG (p < 0.05), although levels of GDF15 were similar to CG (p > 0.05). Levels of GDF8 were similar in the SG and TG groups (p > 0.05), with reductions of GDF15 levels in both training groups (p < 0.05). A total of 12 weeks of astaxanthin supplementation and exercise training decreased adipokines levels, body composition (weight, %fat), anthropometrical factors (BMI), and improved lipid and metabolic profiles. These benefits were greater for men with obesity in the TSG group.

Increased Levels of ANGPTL3 and CTRP9 in Patients With Obstructive Sleep Apnea and Their Relation to Insulin Resistance and Lipid Metabolism and Markers of Endothelial Dysfunction

OBJECTIVE

Obstructive sleep apnea (OSA) has a close relation with obesity and perturbation in adipokines and hepatokines, which are linked to OSA consequences such as insulin resistance, dyslipidemia, and endothelial dysfunction. This study aimed to assess the relation of C1q/TNF-related protein 9 (CTRP9) and angiopoietin-like protein 3 (ANGPTL3) with OSA and biochemical measurements.

METHODS

Serum levels of ANGPTL3, CTRP9, adiponectin, leptin, intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion protein 1 (VCAM-1) were determined in 74 OSA patients and 27 controls using enzyme-linked immunosorbent assay kits.

RESULTS

Levels of ANGPTL3, CTRP9, leptin, ICAM-1, and VCAM-1 were increased in the patients compared to the controls, whereas adiponectin levels decreased. ANGPTL3 had a positive correlation with total cholesterol, triglyceride, low-density lipoprotein cholesterol, ICAM-1, and VCAM-1 and was inversely correlated with leptin. CTRP9 showed a positive correlation with body mass index, insulin resistance, ICAM-1, and VCAM-1.

CONCLUSION

The results indicated the relation of ANGLTP3 and CTRP9 with OSA and its complications, which suggested a possible role for these factors in the consequences of OSA.

The Impact of Obesity on C1q/TNF-Related Protein-9 Expression and Endothelial Function following Acute High-Intensity Interval Exercise vs. Continuous Moderate-Intensity Exercise

C1q-TNF-related protein-9 (CTRP9) increases endothelial nitric oxide synthase and reduces vasoconstrictors. There is limited information regarding exercise-mediated CTRP9 in obesity. The purpose of this study was to compare high-intensity interval exercise (HIIE) and continuous moderate-intensity exercise (CME) on the CTRP9 response and an indicator of endothelial function (FMD) in obese participants. Sixteen young male participants (9 obese and 7 normal-weight) participated in a counterbalanced and caloric equated experiment: HIIE (30 min, 4 intervals of 4 min at 80–90% of VO2 max with 3 min rest between intervals) and CME (38 min at 50–60% VO2 max). Serum CTRP9 and FMD were measured prior to, immediately following exercise, and 1 h and 2 h into recovery. CTRP9 was significantly increased immediately following acute HIIE and CME in both groups (p = 0.003). There was a greater CME-induced FMD response at 2 h into recovery in obese participants (p = 0.009). A positive correlation between CTRP9 and FMD percent change was observed in response to acute CME when combined with both obese and normal-weight participants (r = 0.589, p = 0.016). The novel results from this study provide a foundation for additional examination of the mechanisms of exercise-mediated CTRP9 on endothelial function in individuals with obesity.

Low Complement C1q/TNF-related Protein-13 Levels are Associated with Childhood Obesity But not Binge Eating Disorder

OBJECTIVE

C1q/tumor necrosis factor-related proteins (CTRPs) are recently described members of the adipokine family. CTRP-13, a new member of this family, has been shown to increase insulin sensitivity and had an anorexigenic effect on food intake in experimental studies. The aim was to investigate serum CTRP-13 levels in children with obesity, and its relationship with other adipokines, metabolic parameters, or binge eating disorder (BED).

METHODS

A cross-sectional study was conducted with 105 pubertal children attending a single center. Clinical (metabolic syndrome, BED) and biochemical (glucose, insulin, lipids, leptin, adiponectin, CTRP-13 levels) parameters were assessed.

RESULTS

Sixty children with obesity [24 males (40%); median age 14.7 (13.0-16.4) years] and 45 healthy controls [15 males (33.3%); median age 15.2 (14.1-16.5) years] were included. Serum adiponectin and CTRP-13 levels were significantly lower in children with obesity than controls (7.1 vs 20.1 μg/mL, p<0.001; 64.7 vs 103.8 ng/mL, p<0.001, respectively). CTRP-13 levels correlated negatively with body mass index (Spearman rho=-0.230, p=0.018) and positively with high-density lipoprotein-cholesterol levels (Spearman rho=0.218, p=0.026). There was no significant difference in serum CTRP-13 concentrations in terms of the presence of metabolic syndrome or BED.

CONCLUSION

Childhood obesity seems to be causing dysregulation in adipokine production and function, including the down-regulation of CTRP-13. The positive correlation between CTRP-13 and HDL-C levels suggested a possible effect of this adipokine on lipid metabolism. Thus CTRP-13 may be a novel biomarker for dyslipidemia in childhood obesity.

CTRP14 inactivation alters physical activity and food intake response to fasting and refeeding

Secreted proteins of the C1q/TNF-related protein (CTRP) family play diverse functions in different organ systems. In the brain, CTRP14/C1QL1 is required for the proper establishment and maintenance of synapses between climbing fibers and cerebellar Purkinje cells. Beyond the central nervous system, the function of CTRP14 is largely unknown. A recent genome-wide association study has implicated CTRP14/C1QL1 as a candidate gene associated with total body fat mass. Here, we explored the potential metabolic roles of CTRP14. We show that Ctrp14 expression in peripheral tissues is dynamically regulated by fasting-refeeding and high-fat feeding. In the chow-fed basal state, Ctrp14 deletion modestly reduces glucose tolerance in knockout (KO) male mice and affects physical activity in a sex- and nutritional state-dependent manner. In the ad libitum fed state, Ctrp14 KO male mice have lower physical activity. In contrast, female KO mice have increased physical activity in the fasted and refed states. In response to an obesogenic diet, CTRP14-deficient mice of either sex gained similar weight and are indistinguishable from wild-type littermates in body composition, lipid profiles, and insulin sensitivity. Ambulatory activity, however, is reduced in Ctrp14 KO male mice. Food intake is also reduced in Ctrp14 KO male mice in the refed period following food deprivation. Meal pattern analyses indicate that decreased caloric intake from fasting to refeeding is due, in part, to smaller meal size. We conclude that CTRP14 is largely dispensable for metabolic homeostasis, but highlight context-dependent and sexually dimorphic metabolic responses of Ctrp14 deletion affecting physical activity and ingestive behaviors.NEW & NOTEWORTHY CTRP14 is a secreted protein whose function in the peripheral tissues is largely unknown. We show that the expression of Ctrp14 in peripheral tissues is regulated by metabolic and nutritional state. We generated mice lacking CTRP14 and show that CTRP14 deficiency alters physical activity and food intake in response to fasting and refeeding. Our data has provided new and valuable information on the physiological function of CTRP14.

C1q/Tumor Necrosis Factor-Related Protein 9: Basics and Therapeutic Potentials

C1q/tumor necrosis factor-related protein 9 (CTRP9) is a newly discovered adipokine that is the closest paralog of adiponectin. Proteolytic cleavage of CTRP9 leads to the release of the globular domain (gCTRP9), which serves as the major circulating subtype. After binding with adiponectin receptor 1 (AdipoR1) and N-cadherin, CTRP9 activates various signaling pathways to regulate glucose and lipid metabolism, vasodilation and cell differentiation. Throughout human development and adult life, CTRP9 controls many biological phenomena. simultaneously, abnormal gene or protein expression of CTRP9 is accompanied by a wide range of human pathological phenomena. In this review, we briefly introduce CTRP9 and its associated signaling pathways and physiological functions, which may be helpful in the understanding of the occurrence of diseases. Moreover, we summarize the broader research prospects of CTRP9 and advances in therapeutic intervention. In recent years, CTRP9 has attracted extensive attention due to its role in the pathogenesis of various diseases, providing further avenues for its exploitation as a potential biomarker or therapeutic target.

The Role of Anti-Inflammatory Adipokines in Cardiometabolic Disorders: Moving beyond Adiponectin

The global burden of obesity has multiplied owing to its rapidly growing prevalence and obesity-related morbidity and mortality. In addition to the classic role of depositing extra energy, adipose tissue actively interferes with the metabolic balance by means of secreting bioactive compounds called adipokines. While most adipokines give rise to inflammatory conditions, the others with anti-inflammatory properties have been the novel focus of attention for the amelioration of cardiometabolic complications. This review compiles the current evidence on the roles of anti-inflammatory adipokines, namely, adiponectin, vaspin, the C1q/TNF-related protein (CTRP) family, secreted frizzled-related protein 5 (SFRP5), and omentin-1 on cardiometabolic health. Further investigations on the mechanism of action and prospective human trials may pave the way to their clinical application as innovative biomarkers and therapeutic targets for cardiovascular and metabolic disorders.

The Lyme disease agent co-opts adiponectin receptor-mediated signaling in its arthropod vector

Adiponectin-mediated pathways contribute to mammalian homeostasis; however, little is known about adiponectin and adiponectin receptor signaling in arthropods. In this study, we demonstrate that Ixodes scapularis ticks have an adiponectin receptor-like protein (ISARL) but lack adiponectin, suggesting activation by alternative pathways. ISARL expression is significantly upregulated in the tick gut after Borrelia burgdorferi infection, suggesting that ISARL signaling may be co-opted by the Lyme disease agent. Consistent with this, RNA interference (RNAi)-mediated silencing of ISARL significantly reduced the B. burgdorferi burden in the tick. RNA-seq-based transcriptomics and RNAi assays demonstrate that ISARL-mediated phospholipid metabolism by phosphatidylserine synthase I is associated with B. burgdorferi survival. Furthermore, the tick complement C1q-like protein 3 interacts with ISARL, and B. burgdorferi facilitates this process. This study identifies a new tick metabolic pathway that is connected to the life cycle of the Lyme disease spirochete.

Association Between Serum C1q Tumor Necrosis Factor-Related Protein 9 and the Clinical Characteristics and Prognosis of Ischemic Stroke

Introduction

C1q tumor necrosis factor (TNF)-related protein 9 (CTRP9) is a novel member of the C1q/TNF superfamily. According to our previous review, CTRP9 plays a vital role in the process of cardiovascular diseases, including regulating energy metabolism, modulating vasomotion, protecting endothelial cells, inhibiting platelet activation, inhibiting pathological vascular remodeling, stabilizing atherosclerotic plaques, and protecting the heart. We proposed that CTRP9 could play multiple positive and beneficial roles in vascular lesions in ischemic stroke (IS). Here, we aimed to study the relationship between serum CTRP9 and the etiology, severity, and prognosis of IS patients.

Methods

A total of 302 patients with IS and 173 non-stroke controls were selected from the same hospital, and all patients with IS were followed up 12 months after stroke onset. Stroke etiology was classified according to the Trial of ORG 10172 in Acute Stroke Treatment classification. Symptomatic severity was determined using the National Institutes of Health Stroke Scale score. The lesion volume of acute cerebral ischemia was measured using magnetic resonance imaging (MRI). The unfavorable functional outcome was a combination of death or major disability 12 months after stroke onset. Receiver operating characteristic (ROC) curves and integrated discrimination improvement (IDI) and net reclassification improvement (NRI) statistics were applied in the statistical analysis.

Results

We found that serum CTRP9 levels and the ratios of CTRP9/total cholesterol (TC), CTRP9/triglyceride (TG), CTRP9/low-density lipoprotein cholesterol (LDL-C), and CTRP9/high-density lipoprotein cholesterol (HDL-C) were associated with the presence of IS. Moreover, the serum CTRP9 concentration was positively associated with the severity of IS. Incorporation of CTRP9/LDL-C levels into a fully adjusted model for IS-cardioembolic (CE) improved discrimination and calibration, and significantly improved reclassification. In addition, CTRP9 was a predictor of unfavorable functional outcomes.

Conclusions

All the findings indicated that serum CTRP9 could be a promising blood-derived biomarker for the early evaluation and prognosis assessment of IS.

Trial Registration

Chinese Clinical Trial Registry, ChiCTR1800020330.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-021-00296-7.

Altered adipokines in obese adolescents: a cross-sectional and longitudinal analysis across the spectrum of glycemia

Obesity and type 2 diabetes are rapidly increasing in the adolescent population. We sought to determine whether adipokines, specifically leptin, C1q/TNF-related proteins 1 (CTRP1) and CTRP9, and the hepatokine fibroblast growth factor 21 (FGF21), are associated with obesity and hyperglycemia in a cohort of lean and obese adolescents, across the spectrum of glycemia. In an observational, longitudinal study of lean and obese adolescents, we measured fasting laboratory tests, oral glucose tolerance tests, and adipokines including leptin, CTRP1, CTRP9, and FGF21. Participants completed baseline and 2-year follow-up study visits and were categorized as lean (LC, lean control; n = 30), obese normoglycemic (ONG; n = 61), and obese hyperglycemic (OHG; n = 31) adolescents at baseline and lean (n = 8), ONG (n = 18), and OHG (n = 4) at follow-up. Groups were compared using ANOVA and regression analysis, and linear mixed effects modeling was used to test for differences in adipokine levels across baseline and follow-up visits. Results showed that at baseline, leptin was higher in all obese groups (P < 0.001) compared with LC. FGF21 was higher in OHG participants compared with LC (P < 0.001) and ONG (P < 0.001) and positively associated with fasting glucose (P < 0.001), fasting insulin (P < 0.001), Homeostasis Model Assessment-Insulin Resistance Index (HOMA-IR; P < 0.001), and hemoglobin A1c (HbA1c; P = 0.01). CTRP1 was higher in OHG compared with ONG (P = 0.03). CTRP9 was not associated with obesity or hyperglycemia in this pediatric cohort. At 2 years, leptin decreased in ONG (P = 0.003) and FGF21 increased in OHG (P = 0.02), relative to lean controls. Altered adipokine levels are associated with the inflammatory milieu in obese youth with and without hyperglycemia. In adolescence, the novel adipokine CTRP1 was elevated with hyperglycemia, whereas CTRP9 was unchanged in this cohort.NEW & NOTEWORTHY Leptin is higher in obese adolescents and FGF21 is higher in obese hyperglycemic adolescents. The novel adipokine CTRP1 is higher in obese hyperglycemic adolescents, whereas CTRP9 was unchanged in this adolescent cohort.

Regulation of circulating CTRP-2/CTRP-9 and GDF-8/GDF-15 by intralipids and insulin in healthy control and polycystic ovary syndrome women following chronic exercise training

Background

Polycystic ovary syndrome (PCOS) is associated with obesity, diabetes, and insulin resistance. The circulating C1Q/TNF-related proteins (CTRP-2, CTRP-9) and growth differentiation factors (GDF-8, GDF-15) contribute to glucose and lipid homeostasis. The effects of intralipids and insulin infusion on CTRP-2, CTRP-9, GDF-8 and GDF-15 in PCOS and control subjects before and after chronic exercise training were examined.

Methods

Ten PCOS and nine healthy subjects were studied at baseline status and after moderate-intensity chronic exercise training (1 h exercise, 3 times per week, 8 weeks). All participants were infused with 1.5 mL/min of saline or intralipids (20%) for 5 h, and during the last 2 h of saline or intralipids infusion hyperinsulinemic-euglycemic clamp (HIEC) was performed. CTRP-2, CTRP-9, GDF-8 and GDF-15 levels were measured at 0, 3 and 5 h.

Results

Intralipids dramatically increased CTRP-2 levels in PCOS (P = 0.02) and control (P = 0.004) subjects, which was not affected by insulin infusion or by exercise. Intralipids alone had no effects on CTRP-9, GDF-8, or GDF-15. Insulin increased the levels of GDF-15 in control subjects (P = 0.05) during the saline study and in PCOS subjects (P = 0.04) during the intralipid infusion. Insulin suppressed CTRP9 levels during the intralipid study in both PCOS (P = 0.04) and control (P = 0.01) subjects. Exercise significantly reduced fasting GDF-8 levels in PCOS (P = 0.03) and control (P = 0.04) subjects; however, intralipids infusion after chronic exercise training increased GDF-8 levels in both PCOS (P = 0.003) and control (P = 0.05) subjects and insulin infusion during intralipid infusion reduced the rise of GDF-8 levels.

Conclusion

This study showed that exogenous lipids modulate CTRP-2, which might have a physiological role in lipid metabolism. Since chronic exercise training reduced fasting GDF-8 levels; GDF-8 might have a role in humoral adaptation to exercise. GDF-15 and CTRP-9 levels are responsive to insulin, and thus they may play a role in insulin responses.

[Association between serum CTRP9 levels and diabetic retinopathy in patients with type 2 diabetes mellitus]

OBJECTIVE

To investigate the relationship between serum C1q tumor necrosis factor-related protein 9 (CTRP9) level and the risk of diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM).

OBJECTIVE

A total of 291 patients with T2DM underwent fundus examination, and their serum levels of CTRP9, insulin and adiponectin were measured using enzyme- linked immunosorbent assay. According to results of fundus examination, the patients were divided into DR group and non-DR (NDR) group, and logistic regression was used to analyze the relationship between serum CTRP9 levels and DR in T2DM patients.

OBJECTIVE

Compared with those in NDR group, the patients with DR showed significantly increased serum CTRP9 level (P < 0.001) and decreased serum adiponectin level (P < 0.001). Pearson correlation analysis showed that in patients with T2DM complicated by DR, serum CTRP9 levels had a significant positive correlation with DR stage (P < 0.05) and a negative correlation with serum adiponectin level (P < 0.001). Multivariate logistic regression analysis showed that with the increase of serum CTRP9 level, the risk of DR is significantly increased in patients with T2DM.

OBJECTIVE

In patients with T2DM complicated by DR, an increased serum CTRP9 level suggests a compensatory response to DR.

Increased mRNA Expression of CTRP3 and CTRP9 in Adipose Tissue from Obese Women: Is it Linked to Obesity-Related Parameters and mRNA Expression of Inflammatory Cytokines?

Background

Obesity, a medical condition with impaired adipokine secretion and function, has a detrimental effect on insulin and glucose metabolism. CTRP3 and CTRP9 are adipokines with possible roles in energy homeostasis regulation. We sought to compare CTRP3, CTRP9, and inflammatory gene expression in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) from obese women who underwent bariatric surgery and non-obese women as controls.

Methods

For this study, the investigators recruited 20 morbidly obese women (BMI> 35) who qualified for bariatric surgery and 20 normal-weight women (BMI< 25) who underwent elective surgeries. Real-time PCR was performed to investigate mRNA expression of CTRP3, CTRP9, and the inflammatory genes IL1-β, IL-6, MCP-1, and TNF-α in SAT and VAT from both obese patients and controls.

Results

We observed that CTRP3 mRNA levels were significantly greater in VAT from obese patients than from controls (P< 0.0003). Also, patient group had higher levels of CTRP9 that control group (P< 0.0026). Inflammatory cytokines were markedly increased in SAT of obese patients compared to controls (P< 0.05). In addition, our results revealed a positive correlation of CTRP9 with HOMA-IR and waist circumference in VAT and CTRP3 with IL-1β, MCP-1, and TNF-α in SAT.

Conclusion

Both CTRP3 and CTRP9 expression were significantly higher in VAT from obese patients than from controls, and CTRP3 expression positively correlated with inflammatory parameters. Our findings indicate that CTRP3 and CTRP9 might be important in regulating glucose metabolism and obesity-related conditions such as inflammation.

CTRP9: An emerging potential anti-aging molecule in brain

C1q/tumor necrosis factor (TNF)-related proteins (CTRPs) particularly CTRP9, have been established to be as adiponectin (APN) highly conserved paralogs which assemble several APN regulatory functions. Recently, growing body of evidences drawn significant attention to evaluate metabolic and cardiovascular effect of CTRP9. However, the potential role of CTRP9 in brain tissue has not yet fully illustrated. Here, we aimed to uncover latest advances regarding the CTRP9 related signaling pathways and during brain aging process.

Association of CYP4F2 and CTRP9 polymorphisms and serum selenium levels with coronary artery disease

Aims to explore the interaction between serum selenium level and CYP4F2 and CTRP9 gene polymorphisms in the development of coronary artery disease (CAD).A total of 200 cases of CAD were selected from the Central Hospital of Enshi Tujia and Miao Autonomous Prefecture, Hubei, China, and 200 healthy subjects cases were served as controls. The polymorphism of CYP4F2 and CTRP9 gene was detected by Sanger sequencing, and the serum selenium level was measured by hydride generation atomic fluorescence spectrometry.The serum selenium level in the CAD group was significantly lower than that in the control group. The risk of CAD was decreased in the patients carrying the AA genotype in CYP4F2 rs3093135, while the frequency of the CC genotype of CTRP9 rs9553238 in CAD patients was higher than that in control subjects. Low serum selenium level and CTRP9 rs9553238 CC genotype play a positive role in the occurrence of CAD.The serum selenium level is negatively correlated with CAD. The polymorphism of the CYP4F2 rs3093135 and CTRP9 rs9553238 was significantly related to the susceptibility of CAD, and there is a synergistic effect between the serum selenium level and the CTRP9 rs9553238 CC genotype, which significantly increases the risk of CAD.

C1q/TNF-Related Proteins, HIV and HIV-Associated Factors, and Cardiometabolic Phenotypes in Middle-Aged Women

C1q/tumor necrosis factor (TNF)-related proteins (CTRPs) have been linked to energy homeostasis and vascular health. People with HIV are susceptible to cardiometabolic disease, but the contributions of different CTRPs are unknown. We investigated the associations of HIV and related factors with serum CTRPs, and CTRPs' relationships with cardiometabolic phenotypes. This involved a cross-sectional analysis of participants in the Women's Interagency HIV Study aged ≥35 with (n = 209) and without (n = 92) HIV who underwent carotid ultrasound in 2004-2005 and had stored serum available for measurement of total adiponectin and CTRPs 1, 3, 5, and 9. The Benjamini/Hochberg procedure was used to control the study-wide false-positive rate. HIV-positive women had significantly higher adiponectin than HIV-negative women after adjustment for sociodemographic, behavioral, and clinical variables [beta = 0.29 (95% confidence interval 0.11-0.47)]. Among HIV-positive women, lower CD4 count was associated with higher adiponectin and history of AIDS with higher CTRP9, but these were only nominally significant. There was no relationship between HIV status and CTRP 1, 3, or 5, nor was antiretroviral therapy or viral load associated with any CTRP. In the entire cohort, higher adiponectin was associated with significantly lower fasting glucose and insulin resistance, while higher CTRP5 [beta = -0.02 (-0.033 to -0.007)]-and, at a nominal level, CTRPs 1 and 3-was associated with significantly lower carotid intima-media thickness. In conclusion, in this sample of middle-aged women, HIV serostatus was positively associated with adiponectin, but not CTRPs. In turn, serum adiponectin was inversely associated with glucose dysregulation, whereas CTRP5 was inversely associated with carotid intima-media thickness. Further research is needed to determine CTRPs' role in atherosclerosis.

Obesity is associated with copper elevation in serum and tissues

Copper misbalance has been linked to fat accumulation in animals and experimental systems; however, information about copper homeostasis in human obesity is limited. In this study, the copper status of obese individuals was evaluated by measuring their levels of copper and cuproproteins in serum, adipose and hepatic tissues. The analysis of serum trace elements showed significant positive and element-specific correlation between copper and BMI after controlling for gender, age, and ethnicity. Serum copper also positively correlated with leptin, insulin, and the leptin/BMI ratio. When compared to lean controls, obese patients had elevated circulating cuproproteins, such as semucarbazide-sensitive amine oxidase (SSAO) and ceruloplasmin, and higher SSAO activity and copper levels in visceral fat. Although hepatic steatosis reduces copper levels in the liver, obese patients with no or mild steatosis have higher copper content in the liver compared to lean controls. In conclusion, obese patients evaluated in this study had altered copper status. Strong positive correlations of copper levels with BMI and leptin suggest that copper and/or cuproproteins may be functionally linked to fat accumulation.

C1q/TNF-related protein 3 (CTRP3) and 9 (CTRP9) concentrations are decreased in patients with heart failure and are associated with increased morbidity and mortality

BACKGROUND

Biochemical marker has revolutionized the approach to the diagnosis of heart failure. However, it remains difficult to assess stability of the patient. As such, novel means of stratifying disease severity are needed. C1q/TNF-Related Protein 3 (CTRP3) and C1q/TNF-Related Protein 9 (CTRP9) are novel adipokines that contribute to energy homeostasis with additional anti-inflammatory and anti-ischemic properties. The aim of our study is to evaluate concentrations of CTRP3 and CTRP9 in patients with HFrEF (heart failure with reduced ejection fraction) and whether associated with mortality.

METHODS

Clinical data and plasma were obtained from 176 healthy controls and 168 patients with HFrEF. CTRP3 and CTRP9 levels were evaluated by enzyme-linked immunosorbent assay.

RESULTS

Both CTRP3 and CTRP9 concentrations were significantly decreased in the HFrEF group compared to the control group (p < 0.001). Moreover, patients with higher New York Heart Association class had significantly lower CTRP3 or CTRP9 concentrations. Correlation analysis revealed that CTRP3 and CTRP9 levels were positively related with LVEF% (CTRP3, r = 0.556, p < 0.001; CTRP9, r = 0.526, p < 0.001) and negatively related with NT-proBNP levels (CTRP3, r = - 0.454, p < 0.001; CTRP9, r = - 0.483, p < 0.001). After a follow up for 36 months, after adjusted for age, LVEF and NT-proBNP, we observed that CTRP3 or CTRP9 levels below the 25th percentile was a predictor of total mortality (CTRP3,HR:1.93,95%CI1.03~3.62,P = 0.042;CTRP9,HR:1.98,95%CI:1.02~3.85,P = 0.044) and hospitalizations (CTRP3,HR:2.34,95% CI:1.43~3.82,P = 0.001;CTRP9,HR:2.67,95%CI:1.58~4.50,P < 0.001).

CONCLUSIONS

CTRP3 and CTRP9 are decreased in patients with HFrEF, proportionate to disease severity, and each is associated with increased morbidity and mortality.

TRIAL REGISTRATION

NCT01372800 . Registered May 2011.

Cytokine, Chemokine, and Cytokine Receptor Changes Are Associated With Metabolic Improvements After Bariatric Surgery

Context

Altered cytokine levels and chronic low-grade inflammation contribute to metabolic dysfunction in obesity. The extent of cytokine changes and their impact on metabolic improvements after bariatric surgery have not been fully explored.

Objective

To compare 76 circulating cytokines, chemokines, and secreted cytokine receptors in subjects with obesity and lean subjects and determine how these cytokines are altered by bariatric surgery.

Design, Setting, and Participants

A total of 37 patients with obesity and 37 lean patients in a cross-sectional study at an academic medical center. We also investigated cytokine changes in 25 patients with obesity after bariatric surgery.

Intervention

Bariatric surgery (Roux-en-Y gastric bypass and vertical sleeve gastrectomy).

Main Outcome Measures

Quantification of 76 circulating cytokines, chemokines, and secreted cytokine receptors.

Results

A total of 13 cytokines were significantly higher, and 4 lower, in patients with obesity relative to lean controls. Soluble vascular endothelial growth factor receptor 2 (sVEGFR2), soluble TNF receptor (sTNFR) 1, and sTNFR2 were positively correlated, and soluble receptor for advanced glycation end-products was inversely correlated, with weight and body mass index. sTNFR2 was positively correlated with fasting glucose, homeostatic model assessment of insulin resistance, and hemoglobin A1c. After bariatric surgery, adiponectin increased, and leptin decreased. Elevated sVEGFR2 levels in patients with obesity were decreased (P = 0.01), whereas reduced chemokine (C-X-C motif) ligand (CXCL) 12 levels in patients with obesity increased (P = 0.03) after surgery. Patients with higher soluble interleukin receptor (sIL) 1R2 and sIL-6R levels before surgery had greater weight loss after surgery (P < 0.05).

Conclusions

We demonstrate that chemokine (C-C motif) ligand (CCL) 14, sVEGFR2, and platelet-derived growth factor BB are elevated in obesity, and CXCL12, CCL11, and CCL27 are lower in obesity. We found clinically concordant directionality between lean and patients with obesity and before vs after surgery for six cytokines, suggesting that bariatric surgery shifted the cytokine profiles of patients with obesity toward that of lean controls.

Ctrp9 and adiponectin receptors in Nile tilapia (Oreochromis niloticus): Molecular cloning, tissue distribution and effects on reproductive genes

As the close paralog of adiponectin, C1q/TNF-Related Protein 9 (CTRP9) has been reported to be involved in the regulation of glucose and fat metabolism, immunization and endothelial cell functions. However, information regarding the actions of Ctrp9 on reproduction is extremely limited in fish. As a first step, Ctrp9, adiponectin receptor 1 (Adipor1) and Adipor2 were identified from Nile tilapia. The open reading frame (ORF) of ctrp9 was 1020 bp which encoded a 339 amino acids. Moreover, the ORFs of adipor1 and adipor2 were 1131 bp and 1134 bp encoding 376 and 377 amino acids, respectively. Tissue distribution showed that ctrp9 mRNA levels were highest in the kidney in both sexes. And, the expression of adipor1 and adipor2 were widely distributed in all tissues examined, exhibiting high levels in the brain, gonad, gut and stomach. In addition, intraperitoneal (i.p.) injection of gCtrp9 (globular Ctrp9) suppressed the hypothalamic expression of gnrh2 (gonadotropin-releasing hormone 2) and gnrh3, as well as gthα (gonadotropic hormone α), fshβ (follicle-stimulating hormone β), lhβ (luteinizing hormone β), lhr (LH receptor) and fshr (FSH receptor) mRNA levels in the pituitary. The mRNA levels of adipor1, but not adipor2, in the gonads were also inhibited after injection. Moreover, the levels of serum E2 (estrogen) in female and T (testosterone) in male were significantly decreased after injection of gCtrp9. Overall, our data provides novel data indicating, for the first time, a regulatory effect of CTRP9 on teleost reproduction.

Relationship of Selected Adipokines with Markers of Vascular Damage in Patients with Type 2 Diabetes

BACKGROUND

In this study we compared levels of selected adipokines between patients with type 2 diabetes (T2D) and healthy individuals and we determined their relationship with early vascular damage markers.

METHODS

Seventy-seven subjects: 56 patients with T2D (34 men and 22 women) and 21 healthy controls (8 men and 13 women) were examined in this cross-sectional study. Selected adipokines [adiponectin, adipocyte fatty acid-binding protein (A-FABP), fibroblast growth factor 21 (FGF-21), C1q/TNF-related protein 9 (CTRP-9), and allograft inflammatory factor-1 (AIF-1)] with possible cardiovascular impact were measured in all participants. To identify markers of vascular damage von Willebrand factor (vWF), plasminogen activator inhibitor-1 (PAI-1) and arterial stiffness parameters were examined in all the subjects.

RESULTS

When compared with healthy controls, T2D had significantly higher levels of A-FABP [50.0 (38.1-68.6) vs. 28.6 (23.6-32.9) ng/mL, P < 0.0001] and lower levels of adiponectin [5.9 (4.3-9.0) vs. 11.3 (8.7-14.8) μg/mL, P < 0.0001]. Differences in other adipokines were not statistically significant. Adiponectin level correlated negatively with vWF levels (ρ = -0.29, P < 0.05) and PAI-1 (ρ = -0.36, P < 0.05) and A-FABP positively with vWF (ρ = 0.61, P < 0.05) and PAI-1 (ρ = 0.47, P < 0.05) and augmentation index (ρ = 0.26, P < 0.05). Multivariate regression analysis showed independent association between A-FABP and vWF (b = 0.24, P < 0.05).

CONCLUSIONS

Patients with T2D have significantly higher levels of A-FABP and lower levels of adiponectin. These adipokines correlate with indicators of vascular damage and could contribute to cardiovascular risk in patients with T2D. A-FABP may participate in direct endothelium damage.

Association of circulating CTRP9 with soluble adhesion molecules and inflammatory markers in patients with type 2 diabetes mellitus and coronary artery disease

C1q/TNF-related protein 9 (CTRP9) is a paralogue of adiponectin with known favorable effects on lipid and glucose metabolism. A potential role of CTRP9 for regulation of endothelium function has been suggested by previous studies. However, no studies have examined the relation between serum CTRP9 levels and adhesion molecules in patients with type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD). The present study was conducted on 337 subjects who underwent coronary angiography and were categorized into four groups according to the presence of CAD and T2DM (control, CAD, T2DM and CAD+T2DM). Serum levels of CTRP9, adiponectin, sICAM-1, sVCAM-1, sE-Selectin, IL-6 and TNF-α were measured. It was found that the circulating CTRP9 levels were independently associated with increased risk of CAD and T2DM in addition to elevated levels of serum CTRP9 in CAD, T2DM and CAD+T2DM groups. A significant association of serum CTRP9 levels with adhesion molecules in CAD and T2DM patients as well as serum TNF-α levels in CAD individuals was noted. A significant relation between the circulating levels of CTRP9 and HOMA-IR in T2DM subjects was also observed. The results revealed increased circulating levels of CTRP9 in T2DM and CAD individuals which suggests a compensatory response to insulin resistance, inflammatory milieu and endothelial dysfunction; however, more studies are needed to confirm this.

Circulating CTRP9 levels are increased in patients with newly diagnosed type 2 diabetes and correlated with insulin resistance

AIMS

C1q/TNF-related protein-9 (CTRP9) is a novel adipokine that has been shown to promote lipid metabolism, enhance insulin sensitivity and protect against cardiovascular disease. However, previous studies in humans have produced controversial results regarding the association between CTRP9 and insulin resistance. The objective of this study was to evaluate the relationships between CTRP9 and insulin resistance in Chinese population.

METHODS

Subjects with normal glucose tolerance (NGT, n=108), impaired glucose tolerance (IGT, n=92), and newly diagnosed type 2 diabetes mellitus (nT2DM, n=106) were recruited to determining the circulating CTRP9 and adiponectin levels by enzyme linked immunosorbent assay. Anthropometric and biochemical measurements related to insulin resistance, adiposity and lipid profile were examined for all participants. Oral glucose tolerance test was performed in healthy subjects (17 male and 17 female).

RESULTS

Circulating CTRP9 level was significantly higher in both IGT and nT2DM than in individuals with NGT. Overweight/obese subjects had much higher CTRP9 levels than lean individuals, and in all subjects, females also had higher CTRP9 levels than males. In addition, circulating CTRP9 level was positively correlated with markers of obesity and insulin resistance, including body mass index, fasting blood glucose, insulin, HbA1c, homeostasis model assessment of insulin resistance and low-density lipoprotein-cholesterol, while was inversely correlated with high-density lipoprotein-cholesterol and adiponectin. Moreover, hyperglycemia during an oral glucose challenge increased circulating CTRP9 concentrations.

CONCLUSIONS

We conclude that CTRP9 was strongly associated with insulin resistance, suggesting that CTRP9 might be important in the development of type 2 diabetes.

Circulating C1q complement/TNF-related protein (CTRP) 1, CTRP9, CTRP12 and CTRP13 concentrations in Type 2 diabetes mellitus: In vivo regulation by glucose

OBJECTIVES

The C1q complement/TNF-related protein (CTRP) superfamily, which includes the adipokine adiponectin, has been shown in animal models to have positive metabolic and cardiovascular effects. We sought to investigate circulating CTRP1, CTRP9, CTRP12 and CTRP13 concentrations in persons with type 2 diabetes mellitus (T2DM), with age and BMI matched controls, and to examine the effects of a 2 hour 75g oral glucose tolerance test (OGTT) on serum CTRP1, CTRP9, CTRP12 and CTRP13 levels in persons with T2DM.

DESIGN

Cross-sectional study [newly diagnosed T2DM (n = 124) and control (n = 139) participants]. Serum CTRP1, CTRP9, CTRP12 and CTRP13 were measured by ELISA.

RESULTS

Systolic and diastolic blood pressure, total cholesterol (TCH), Low-density lipoprotein (LDL)-cholesterol, triglycerides, TCH/High-density lipoprotein (HDL) ratio, triglycerides/HDL ratio, glucose, insulin, homeostatic model assessment-insulin resistance (HOMA-IR), C-reactive protein and endothelial lipase were significantly higher, whereas leptin and adiponectin were significantly lower in T2DM participants. Serum CTRP1 were significantly higher and CTRP12 significantly lower in T2DM participants. Age, diastolic blood pressure, glucose and CTRP12 were predictive of serum CTRP1; leptin was predictive of serum CTRP9; glucose and CTRP1 were predictive of serum CTRP12; endothelial lipase was predictive of serum CTRP13. Finally, serum CTRP1 were significantly higher and CTRP12 significantly lower in T2DM participants after a 2 hour 75g OGTT.

CONCLUSIONS

Our data supports CTRP1 and CTRP12 as potential novel biomarkers for the prediction and early diagnosis of T2DM. Furthermore, pharmacological agents that target CTRP1 and CTRP12 could represent a new strategy in the treatment of T2DM.

Plasma C1q/TNF-Related Protein-9 Levels Are Associated with Atherosclerosis in Patients with Type 2 Diabetes without Renal Dysfunction

Aim. C1q/tumor necrosis factor-related protein-9 (CTRP9), a paralog of adiponectin, is expressed in adipose tissue. CTRP9 exerts protective effects against obesity and atherosclerosis in rodents. We investigated the association between plasma CTRP9 levels and atherosclerosis in patients with type 2 diabetes. Methods. We included 419 patients with type 2 diabetes, 161 of whom had chronic kidney disease (CKD). Fasting plasma CTRP9 and total adiponectin levels were measured with enzyme-linked immunosorbent assay. The intima-media thickness (IMT) of the common carotid artery was measured with ultrasonography. Results. Plasma CTRP9 levels were higher in the CKD group than in the non-CKD group. Plasma CTRP9 levels were positively correlated with carotid IMT in the non-CKD group. Multivariate analyses revealed that plasma CTRP9 levels were positively associated with carotid IMT in the non-CKD group, independent of age, sex, body mass index, adiponectin, and other cardiovascular risk factors. However, plasma CTRP9 levels were not associated with carotid IMT in the CKD group. Conclusion. Plasma CTRP9 levels are associated with atherosclerosis in diabetic patients without CKD, independently of obesity, adiponectin, and traditional cardiovascular risk factors. This study indicates a potential role of CTRP9 in atherosclerosis progression in human type 2 diabetes.