Triglyceride to high-density lipoprotein cholesterol ratio and carotid intima-medial thickness in Chinese adolescents with newly diagnosed type 2 diabetes mellitus.

OBJECTIVE: To investigate the relationship between triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio and carotid intima-medial thickness (CIMT) in Chinese youth and adolescents with newly diagnosed type 2 diabetes mellitus (T2DM). METHODS: Ninety-eight subjects aged 10-24 yr with newly-diagnosed T2DM had general inflammation, anthropometric, laboratory and CIMT data collected, and were divided into three groups based on TG/HDL-C tertiles. RESULTS: There were no significant differences in gender, age, fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), and carotid arterial diameter (CAD) among the groups based on TG/HDL-C tertiles. Across TG/HDL-C tertiles, there was a significant progressive increase in body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), homeostasis model assessment-estimated insulin resistance (HOMA-IR), TG, total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C) and CIMT (all P < 0.01 or P < 0.05), while HDL-C was decreased significantly across the groups (P < 0.01). In general linear regression model, TG/HDL-C was an independent determinant of CIMT even after adjusting for BMI, SBP, DBP, TG, TC, LDL-C, HDL-C, HbA1c and HOMA-IR. CONCLUSION: TG/HDL-C ratio, the marker of small dense LDL particles, is an independent determinant of CIMT in Chinese youth and adolescents with newly diagnosed T2DM, and may be a simple and helpful tool in predicting the increased CIMT in such patients.

Low-Grade Inflammation and Increased Arterial Stiffness in Chinese Youth and Adolescents with Newly-Diagnosed Type 2 Diabetes Mellitus.

OBJECTIVE: To investigate the relationship between low-grade inflammation (LI) and increased arterial stiffness in Chinese youth and adolescents with newly-diagnosed type 2 diabetes mellitus (T2DM). METHODS: Ninety-eight subjects aged 10 to 24 years with newly-diagnosed T2DM were investigated for findings of general inflammation. Anthropometric measurements were taken. Data related to arterial stiffness [brachial artery distensibility (Branch D), augmentation index (AIx), carotid-femoral pulse wave velocity (CF-PWV)] were collected. The subjects were divided into a non-LI group (NLI, n=42) and a LI group (n=56) according to their high-sensitivity C-reactive protein (Hs-CRP) levels. RESULTS: There were no significant differences in age and gender between the LI group and the NLI group. CF-PWV and AIx values of the LI group were higher than those of the NLI group (p<0.01), while Branch D values were lower in the LI group (p<0.01). Branch D, CF-PWV, and AIx values correlated significantly with Hs-CRP overall (r=-0.32, 0.34, 0.33, all p<0.01). Multivariate models revealed that in either group (LI or NLI), Hs-CRP, as a continuous variable, was an independent determinant of arterial stiffness parameters even after adjusting for other risk factors. CONCLUSION: Newly-diagnosed T2DM youth and adolescents with LI present a more adverse cardiovascular disease risk profile and stiffer arteries. Hs-CRP levels correlated with arterial stiffness parameters and constituted an independent determinant of arterial stiffness.

CTRP3 improves the insulin sensitivity of 3T3-L1 adipocytes by inhibiting inflammation and ameliorating insulin signalling transduction.

INTRODUCTION: C1q/TNF-related Protein-3 (CTRP3) is a novel adipokine with multiple effects such as lowering glucose levels, inhibiting glyconeogenesis in the liver, and increasing angiogenesis and anti-inflammation. But little is known about the effects of CTRP3 on insulin resistance in adipose tissue. This study aims to investigate the effects and mechanisms of CTRP3 on the insulin sensitivity of 3T3-L1 adipocytes. MATERIAL AND METHODS: Insulin resistant 3T3-L1 adipocytes were induced by palmic acid cultivation. Such adipocytes were treated with recombinant CTRP3 protein at different concentrations (0, 10, 50, 1,250 ng/mL) for 12 hours, and at a concentration of 250 ng/mL for differing times (2, 6, 12, and 24 h). Another group was pre-treated with wortmannin, the special inhibitor of phosphatidylinositol-4,5- bisphosphate 3-kinase (PI3K), for 20 minutes before the treatment with 250 ng/mL CTRP3. The glucose consumption, the glucose uptake, the expression and release of tumour necrosis factor α (TNF-α) and interleukin-6(IL-6) in supernatant, and the protein relative expression of PI3K and protein kinase B (PKB)(ser437) were detected. RESULTS: Compared to the control group, glucose consumption in the CTRP3 intervention group at concentrations of 10, 50, 250, and 1,250 ng/mL was increased by 22.1%, 42.9%, 76.6% and 80.5% respectively (all P < 0.01); the glucose uptake was increased by 39.0%, 68.0%, 108.0% and 111.0% respectively (all P < 0.01); the content of TNF-α in the culture media of CTRP3 (10, 50, 250 ng/mL) intervention group was decreased by 7.6% (P > 0.05), 13.0% (P < 0.05) and 17.4% (P < 0.01) respectively; the content of IL-6 was decreased by 7.1%, 12.4% and 17.1% respectively (all P < 0.01); the protein relative expression of PI3K was increased by 0.63-, 1.00- and 1.36-fold respectively (all P < 0.01), and PKB(ser437) increased by 0.65-, 1.61- and 1.93-fold respectively (all P < 0.01); the mRNA relative expression of GLUT-4 was increased by 23.0%, 47.0% and 62.0% respectively (all P < 0.01). After the treatment with wortmannin, glucose consumption, glucose uptake, PI3K and PKB(ser437) protein relative expression, as well as GLUT-4 mRNA relative expression, was decreased by 53.2%, 44.7%, 43.4%, 56.1 and 30.9% respectively (all P < 0.01). CONCLUSIONS: CTRP3 could improve insulin sensitivity of insulin resistant 3T3-L1 adipocytes by decreasing inflammation and ameliorating insulin signalling transduction, indicating that CTRP3 may be a new target for the prevention and cure of insulin resistance and type 2 diabetes.

Expression of CTRP3, a novel adipokine, in rats at different pathogenic stages of type 2 diabetes mellitus and the impacts of GLP-1 receptor agonist on it.

This study aimed to investigate the expression of C1q/TNF-related protein-3 (CTRP3) in rats at different pathogenic stages of type 2 diabetes mellitus (T2DM) and the impacts of glucagon-like peptide-1 (GLP-1) receptor agonist on it. Male wistar rats were fed with high-fat diet for 10 weeks to induce insulin resistance (IR) and then were given low-dose streptozotocin (STZ) intraperitoneal injection to induce T2DM. Exendin-4 (Ex-4), a GLP-1 receptor agonist, was subcutaneous injected to the IR rats and T2DM rats for 4 weeks. The expression of CTRP3 mRNA and protein in epididymis adipose tissue of rats at the stage of IR was lower significantly than that of normal control (NC) rats and decreased more when they were at the stage of overt T2DM (all P < 0.05 or P < 0.01). After the treatment with Ex-4, the mRNA and protein expressions of CTRP3 were increased by 15.5% (P < 0.01) and 14.8% (P < 0.05), respectively, in IR rats and increased by 20.6% (P < 0.01) and 16.5% (P < 0.05), respectively, in T2DM rats. Overall, this study found that the expression of CTRP3 in visceral adipose tissue was progressively decreased in a T2DM rat model from the pathogenic stage of IR to overt diabetes, while Ex-4 treatment increased its expression in such animals.

CTRP3 modulates the expression and secretion of adipokines in 3T3-L1 adipocytes.

The objective of this study was to investigate the impact of C1q/TNF related protein 3 (CTRP3), a novel adipokine, on the expression and secretion of adiponectin, leptin, visfatin, and apelin in 3T3-L1 adipocytes. The effect of insulin resistance on the impact was also investigated. 3T3-L1 adipocytes were treated with different concentrations (0, 10, 50, 250, 1250 ng/mL) CTRP3 for 12 h, and with 250 ng/mL CTRP3 for different times (0, 6, 12, 24, 48 h). The expression of adipokines between normal and insulin resistant adipocytes, as well as between the adipocytes pre-treated with and without Compound C were compared. The secretion and gene expression of the adipokines were detected by enzyme-linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (RT-PCR), respectively. The relative expression of AMPK (thr172) was detected by western blot analysis. With the increase in CTRP3 concentration or the duration of the treatment, the secretion of adiponectin, leptin, visfatin and apelin were all increased accordingly, which was significant under the treatment with 250 ng/mL and 1250 ng/mL CTRP3 for 12 h as well as 250 ng/mL CTRP3 for 12 h, 24 h and 48 h. Gene expression showed a similar trend. The secretion and gene expression of adipokines in insulin resistant adipocytes were all decreased significantly in comparison with that of normal adipocytes. The secretion secretion and gene expression of adiponectin, and the relative expression of AMPK (thr172) in adipocytes pre-treated with Compound C were decreased significantly in comparison with that in adipocytes without Compound C pretreatment. Thus, CTRP3 increased the expression and secretion of adiponectin, leptin, visfatin, and apelin in 3T3-L1 adipocytes, while insulin resistance inhibited the effects. CTRP3 up-regulated the expression of adiponectin in 3T3-L1 adipocytes through AMPK signaling pathway.