ANGPTL3 Levels Research Articles

Circulating angiopoietin-like protein 2 levels and mortality risk in patients receiving maintenance hemodialysis: a prospective cohort study

Patients undergoing hemodialysis treatment have a poor prognosis, as many develop premature aging. Systemic inflammatory conditions often underlie premature aging phenotypes in uremic patients. We investigated whether angiopoietin-like protein 2 (ANGPTL 2), a factor that accelerates the progression of aging-related and noninfectious inflammatory diseases, was associated with increased mortality risk in hemodialysis patients. We conducted a multicenter prospective cohort study of 412 patients receiving maintenance hemodialysis and evaluated the relationship between circulating ANGPTL2 levels and the risk for all-cause mortality. Circulating ANGPTL2 levels were log-transformed to correct for skewed distribution and analyzed as a continuous variable. Of 412 patients, 395 were included for statistical analysis. Time-to-event data analysis showed high circulating ANGPTL2 levels were associated with an increased risk for all-cause mortality after adjustment for age, sex, hemodialysis vintage, nutritional status, metabolic parameters and circulating high-sensitivity C-reactive protein levels {hazard ratio [HR] 2.04 [95% confidence interval (CI) 1.10-3.77]}. High circulating ANGPTL2 levels were also strongly associated with an increased mortality risk, particularly in patients with a relatively benign prognostic profile [HR 3.06 (95% CI 1.86-5.03)]. Furthermore, the relationship between circulating ANGPTL2 levels and mortality risk was particularly strong in patients showing few aging-related phenotypes, such as younger patients [HR 7.99 (95% CI 3.55-18.01)], patients with a short hemodialysis vintage [HR 3.99 (95% CI 2.85-5.58)] and nondiabetic patients [HR 5.15 (95% CI 3.19-8.32)]. We conclude that circulating ANGPTL2 levels are positively associated with mortality risk in patients receiving maintenance hemodialysis and that ANGPTL2 could be a unique marker for the progression of premature aging and subsequent mortality risk in uremic patients, except those with significant aging-related phenotypes.

Association of serum angiopoietin-like protein 2 with elevated risk of cardiovascular diseases in subjects with type 2 diabetes

AimsAlthough previous data have suggested ANGPTL2 and ANGPTL8 (betatrophin) to be related to atherosclerosis in humans, little is known whether this applies in patients with type 2 diabetes (T2D). In this work, we investigate association of serum ANGPTL2 and betatrophin with the risk of cardiovascular diseases (CVD) in T2D patients. MethodsWe measured serum levels of ANGPTL2 and betatrophin in 150 T2D patients with and without CVD and in 100 control subjects. ResultsSerum ANGPTL2 was significantly higher in T2D patients than in controls (p < 0.0001), and in T2D + CVD patients than T2D only patients (p = 0.0002). Serum betatrophin was lower in T2D patients than in controls but with no statistical significance (p = 0.07). Elevated serum ANGPTL2 associated with 2.83-fold increased risk of T2D and with 1.18-fold elevated risk of CVD among T2D patients with positive correlations with markers of hyperglycemia, insulin resistance and atherogenic lipid profile. ROC curve indicated ANGPTL2 as risk biomarker for T2D and CVD with sensitivity of 92.2% and 86%; and specificity of 86.7% and 58%; respectively. ConclusionWe indicate for the first time serum ANGPTL2 as an independent risk biomarker for CVD in T2D patients. Future studies are needed to reveal its role in disease pathogenesis.

Short-Term Cooling Increases Plasma ANGPTL3 and ANGPTL8 in Young Healthy Lean Men but Not in Middle-Aged Men with Overweight and Prediabetes.

Angiopoietin-like proteins (ANGPTLs) regulate triglyceride (TG)-rich lipoprotein distribution via inhibiting TG hydrolysis by lipoprotein lipase in metabolic tissues. Brown adipose tissue combusts TG-derived fatty acids to enhance thermogenesis during cold exposure. It has been shown that cold exposure regulates ANGPTL4, but its effects on ANGPTL3 and ANGPTL8 in humans have not been elucidated. We therefore investigated the effect of short-term cooling on plasma ANGPTL3 and ANGPTL8, besides ANGPTL4. Twenty-four young, healthy, lean men and 20 middle-aged men with overweight and prediabetes were subjected to 2 h of mild cooling just above their individual shivering threshold. Before and after short-term cooling, plasma ANGPTL3, ANGPTL4, and ANGPTL8 were determined by ELISA. In young, healthy, lean men, short-term cooling increased plasma ANGPTL3 (+16%, p < 0.05), ANGPTL4 (+15%, p < 0.05), and ANGPTL8 levels (+28%, p < 0.001). In middle-aged men with overweight and prediabetes, short-term cooling only significantly increased plasma ANGPTL4 levels (+15%, p < 0.05), but not ANGPTL3 (230 ± 9 vs. 251 ± 13 ng/mL, p = 0.051) or ANGPTL8 (2.2 ± 0.5 vs. 2.3 ± 0.5 μg/mL, p = 0.46). We show that short-term cooling increases plasma ANGPTL4 levels in men, regardless of age and metabolic status, but only overtly increases ANGPTL3 and ANGPTL8 levels in young, healthy, lean men.

The association of angiopoietin-like peptide 4 levels with obesity and hepatosteatosis in adolescents

IntroductionAngiopoietin-like peptide 4 (ANGPTL-4) is an adipocytokine that regulates plasma lipoprotein levels by inhibiting the lipoprotein lipase enzyme. Changes in lipid profile can be seen in obese adolescents. Nonalcoholic fatty liver disease may also be a complication of obesity. Based on this information, in this study we aimed to evaluate the relationship between serum ANGPTL-4 levels and obesity and hepatosteatosis in adolescents. Materials and methodsA total of 85 volunteer adolescents, 55 of them were obese and 30 of them were normal weight, were included in our study. The adolescents having body mass index (BMI) 95% percentile and over according to age and sex was defined as obese. Thirty patients with grade 2–3 hepatosteatosis in abdominal ultrasound (USG) were included in ‘obese adolescents with hepatosteatosis’ subgroup and 25 obese cases with no hepatosteatosis in the USG were included in the ‘obese adolescents without hepatosteatosis′ group. Thirty patients with no hepatosteatosis in the abdominal USG and having BMI in normal percentiles according to their age and sex constituted the ‘healthy control adolescents′ group. Serum ANGPTL-4 levels were measured by Enzyme Linked Immunosorbent Assay. Laboratory tests, gender, age and BMI levels were compared statistically between groups. Correlations between ANGPTL-4 and other laboratory parameters were examined statistically in obese adolescent group. ResultsThe BMI, ANGPTL-4, HbA1c, AST, ALT, total cholesterol, triglyceride, LDL-cholesterol, HOMA-IR and insulin levels of the obese adolescent group were found to be significantly higher than the healthy control group (p < 0.05). We found no statistically significant difference in BMI, ANGPTL-4, triglyceride, insulin and HOMA-IR levels among obese adolescents with or without hepatosteatosis (p > 0.05). In all obese adolescent groups and in obese adolescent group with hepatosteatosis; there was no statistically significant relationship between ANGPTL-4 and other variables (p > 0.05). ConclusionsWe found that the levels of ANGPTL-4 increases in obesity in adolescents. However, our results make it difficult to establish a relationship between hepatosteatosis and ANGPTL-4. Targeting ANGPTL-4 may be beneficial for the pathogenesis and associated complications of obesity.

Determination of liver fibrosis stages in Egyptian chronic hepatitis B patients by a noninvasive tool

Background/aimHepatitis B virus (HBV) infection is the leading cause of liver fibrosis (LF). The prognosis and management of patients with chronic hepatitis B virus depend on the amount and progression of liver fibrosis. Angiopoietin-like protein 2 (Angptl2) is not only a chronic inflammatory mediator, but also a tissue-remodeling factor. The aim of this study is to explore the predictive value of Angptl2 in different fibrosis stages in patients chronically infected with HBV. Materials and methods Eighty patients with chronic HBV infection undergoing Fibroscan were included. Serum concentrations of Angptl2 were detected using a commercial ELISA kit.Results Angptl2 levels were significantly associated with liver fibrosis stages (P = 0.02). The area under the curve (AUC) of Angptl2 for distinguishing patients who showed significant fibrosis (F2–F4) was70.2%. Angptl2 with fibrosis-4 (FIB-4) and Angptl2 with AST/platelets ratio (APRI) performed best with an AUC of 92.5%. ConclusionIn patients with chronic HBV infection, Angptl2 level represents a potential biomarker independently associated with fibrosis stages. The combination of Angptl2 with FIB-4 or Angptl2 with APRI performed better than the existing models for diagnosing significant fibrosis.

Circulating Angptl3 and Angptl8 Are Increased in Patients with Hypothyroidism.

Purpose Angiopoietin-like proteins (Angptls) play critical roles in biological processes, primarily in lipid metabolism. The functional state of the thyroid has a profound influence on metabolism in the human body. Therefore, the aim of this study was to investigate possible changes in serum Angptl3, 4, and 8 levels in hypothyroid patients. Methods The study included 29 patients with clinical hypothyroidism, 30 patients with subclinical hypothyroidism, and 29 healthy subjects. Baseline clinical indices, including serum thyroid function tests, were recorded and serum Angptl3, 4, and 8 levels were measured across the three groups. Results Serum Angptl3 and 8 levels were significantly higher in the hypothyroid groups compared to the control group (p < 0.05). There were no differences in Angptl4 levels among the three groups (p > 0.05). Positive correlations were identified between Angptl3 and high-density lipoprotein cholesterol (r = 0.431, p < 0.001), and there was a negative correlation between Angptl3 and total tri-iodothyronine (TT3) (r = -0.220, p = 0.047) and free tri-iodothyronine (r = - 0.279, p = 0.013) levels. Angptl8 was positively correlated with triglyceride (r = 0.267, p = 0.012) and cholesterol levels (r= 0.235, p = 0.028) but was negatively correlated with tri-iodothyronine (r = -0.24, p = 0.031). Furthermore, we used receiver operating characteristic curve analysis to evaluate the diagnostic performance of Angptl3 and 8 in discriminating thyroid dysfunction. The area under curve for detecting thyroid dysfunction based on Angptl3 and Angptl8 was 0.763. Conclusions Our data show that serum Angptl3 and 8 levels are increased in clinical and subclinical hypothyroid patients and that Angptl3 and 8 may serve as possible biomarkers of hypothyroid disease.

Glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 and angiopoietin-like protein 4 are associated with the increase of lipoprotein lipase activity in epicardial adipose tissue from diabetic patients

Background and aimsEpicardial adipose tissue (EAT) is a visceral AT, surrounding myocardium and coronary arteries. Its volume is higher in Type 2 diabetic (DM2) patients, associated with cardiovascular disease risk. Lipoprotein lipase (LPL) hydrolyses triglycerides (TG) from circulating lipoproteins, supplying fatty acids to AT, contributing to its expansion. We aimed to evaluate LPL expression and activity in EAT from DM2 and no DM2 patients, and its regulators ANGPTL4, GPIHBP1 and PPARγ levels, together with VLDLR expression and EAT LPL association with VLDL characteristics. MethodsWe studied patients undergoing coronary by-pass graft (CABG) divided into CABG-DM2 (n = 21) and CABG-noDM2 (n = 29), and patients without CABG (No CABG, n = 30). During surgery, EAT and subcutaneous AT (SAT) were obtained, in which LPL activity, gene and protein expression, its regulators and VLDLR protein levels were determined. Isolated circulating VLDLs were characterized. ResultsEAT LPL activity was higher in CABG-DM2 compared to CABG-noDM2 and No CABG (p=0.002 and p<0.001) and in CABG-noDM2 compared to No CABG (p=0.02), without differences in its expression. ANGPTL4 levels were higher in EAT from No CABG compared to CABG-DM2 and CABG-noDM2 (p<0.001). GPIHBP1 levels were higher in EAT from CABG-DM2 and CABG-noDM2 compared to No CABG (p= 0.04). EAT from CABG-DM2 presented higher PPARγ levels than CABG-noDM2 and No CABG (p=0.02 and p=0.03). No differences were observed in VLDL composition between groups, although EAT LPL activity was inversely associated with VLDL-TG and TG/protein index (p<0.05). ConclusionsEAT LPL regulation would be mainly post-translational. The higher LPL activity in DM2 could be partly responsible for the increase in EAT volume.

Angiopoietin-Like 3 Protein Inhibition: A New Frontier in Lipid-Lowering Treatment.

Angiopoietin-like 3 protein (ANGPTL3) is an inhibitor of both lipoprotein lipase and endothelial lipase in humans. Population studies indicate a relationship between loss of function mutations in ANGPTL3 and favorable reductions in triglycerides and non- high-density lipoprotein cholesterol. In addition, loss of function mutations is associated with a reduced risk of coronary artery disease. Whereas ANGPTL3's role in human lipid metabolism has yet to be fully clarified, it is unlikely that ANGPTL3 impacts cholesterol uptake via the low-density lipoprotein-receptor, unlike the proprotein convertase subtilisin/kexin9 inhibitors. In contrast to other forms of lipid-lowering therapy, ANGPTL3 inhibition may improve insulin sensitivity. The promise of this new therapy, particularly its independence from the low-density lipoprotein-receptor, has prompted the creation of a monoclonal antibody inhibitor; evinacumab. Evinacumab has shown favorable lipid-lowering action in both human and mouse models. Efficacy trials are currently ongoing and will be completed in the near future. In addition, ANGPTL3 inhibition via an antisense oligonucleotide was performed in healthy human subjects, which resulted in a dose-dependent reduction in circulating ANGPTL3 levels and an antiatherogenic lipid profile. When tested in mouse models, administration of the antisense oligonucleotide caused a reduction in progression of atherosclerosis. Further investigation is required to evaluate the efficacy, safety and net benefit of clinical ANGPTL3 inhibition before it can be accepted into clinical practice.

ANGPTL3 inhibits renal cell carcinoma metastasis by inhibiting VASP phosphorylation

Angiopoietin-like proteins (ANGPTLs) comprise a group of proteins that are structurally similar to angiopoietins. In our previous studies, we found that ANGPTL3 can inhibit sorafenib resistance in renal cell carcinoma (RCC). According to bioinformatics analysis based on data in the Cancer Genome Atlas (TCGA), we found that expression of ANGPTL3 was significantly lower in RCC tissues than in adjacent tissues and that disease-free survival and overall survival were significantly shorter in patients with lower ANGPTL3 levels than in those with higher ANGPTL3 levels. Consistent with these results, we demonstrated that RCC tissues exhibited lower ANGPTL3 mRNA and protein expression levels than paired adjacent tissues. Moreover, we found that ANGPTL3 upregulation was associated with better clinical outcomes in RCC patients. ANGPTL3 overexpression inhibited the metastatic ability in RCC cells. Mechanistically, ANGPTL3 binds to vasodilator-stimulated phosphoprotein (VASP) and inhibits its phosphorylation at amino acid 157 in RCC cells. Finally, ANGPTL3 expression and VASP-157 phosphorylation may be combined to predict the prognosis of RCC patients. Overall, our findings describe the role of ANGPTL3 in inhibiting RCC metastasis and thus provide new molecular markers for RCC treatment and prognosis.

Circulating ANGPTL8 Is Associated with the Presence of Metabolic Syndrome and Insulin Resistance in Polycystic Ovary Syndrome Young Women.

Background ANGPTL8 has been reported to be a regulator of lipid metabolism, and it is associated with insulin resistance (IR) and metabolic syndrome (MetS). We investigated whether ANGPTL8 plays a role in MetS. Methods ANGPTL8 and adiponectin concentrations were measured in PCOS patients with or without MetS and in their corresponding healthy controls. The association of circulating ANGPTL8 with adiponectin and other parameters was also examined. Results Circulating ANGPTL8 concentrations were higher in PCOS women with MetS than in those without MetS and in the controls (P < 0.01). ANGPTL8 was positively correlated with age, BMI, FAT%, WHR, SBP, TG, FBG, HbA1c, Fins, and HOMA-IR (all P < 0.01) in the study populations and negatively associated with adiponectin and M-values (P < 0.001). In addition, ANGPTL8 was positively correlated with PRL, LH, TEST, and FAI and negatively correlated with SHBG (all P < 0.01). ROC curve analyses showed that the AUCMetS was 0.87 (P < 0.001), with a sensitivity of 92.4% and specificity of 75.4%, and the AUCIR was 0.82 (P < 0.01), with a sensitivity of 76.4% and specificity of 75.6%. Conclusion ANGPTL8 levels progressively decrease from PCOS patients with MetS to those without MetS and may be a serum marker associated with the degree of metabolic disorders.

1884-P: Serum ANGPTL2, ANGPTL3, and ANGPTL4 as Potential Biomarkers for Diagnosis of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease that seriously affects public health around the world. We investigate the circulating levels of ANGPTL2, ANGPTL3 and ANGPTL4, and detects the correlation with metabolic and biochemical parameters, then examines the efficacy of ANGPTLs for the assessment of NAFLD. Serum levels of ANGPTL2, ANGPTL3, ANGPTL4 and ANGPTL6 in NAFLD patients (n=52) and non NAFLD subjects (n=52) were quantified by ELISA. Then we further evaluated the utility of ANGPTLs as biomarkers for predicting NAFLD by employing receiver operating characteristic (ROC) analysis. Our data demonstrate that (1) serum levels of ANGPTL2 and ANGPTL4 increased, ANGPTL3 level decreased along with the transition from no NAFLD to NAFLD and from mild NAFLD to moderate-to-severe NAFLD patients. However, ANGPTL6 level unchanged altered among these stages; (2) Pearson association analysis demonstrated that ANGPTL2 levels were positively correlated with ALT, AST and GGT; but ANGPTL3 levels were negatively associated with ALT and GGT; ANGPTL4 levels were positively correlated with ALT, AST and GGT; (3) The area under the ROC curve (AUC) for ANGPTL2, ANGPTL3 and ANGPTL4 were 0.647, 0.746 and 0.666; When the three factors were jointly analyzed, the area under the ROC curve was 0.778, exhibiting the strongest capability in predicting diagnosis in NAFLD patients; (4) The changes of serum ANGPTL2 and ANGPTL3 in NAFLD patients may be due to the changed expression in liver tissues of NAFLD patients; (5) Gene enrichment analysis results show a positive correlation between ANGPTL2 level and the activation of NF-κB signaling in NAFLD samples, and a negative correlation between ANGPTL3 level and the activation of JNK signaling in NAFLD samples. Taken together, ANGPTL2, ANGPTL3 and ANGPTL4 levels might be new and important predictors of the severity of NAFLD. Disclosure Y. Ma: None. Y. Wang: None. X. Wang: None. L. Yang: None. J. Lang: None. D. Zhao: None. Funding National Natural Science Foundation of China; National Science Funding in China

608-P: High er Level of Angiopoietin-Like Protein-2 Is Associated with Diabetic Macular Edema in Patients with Type 2 Diabetes Mellitus

Background: Diabetic macular edema (DME) is characterized by hyperpermeability of retinal blood vessels and subsequent formation of hard exudates and macular edema. ANGPTL2 is associated with microvascularization and angiopoiesis, so we investigate the relationship between ANGPTL2 and occurrence of DME. Methods: 222 patients with type 2 diabetic patients were enrolled and divided into 3 groups with matched gender, age and BMI: 1) DM group: patients without diabetic retinopathy (DR) and DME, 2) DR without DME group, and 3) DR with DME group. All subjects were performed optical coherence tomography scanning (OCT) and fundus photography. ANGPTL2 was measured by Elisa. We analyzed the OCT values of concentric circles of macular central fovea with average diameters of 1 mm (R1), 3 mm (R3) and 6 mm (R6) to diagnose DME. Multivariable regression analysis was performed to estimate association between ANGPTL2 and DME. Results: Values of duration of diabetes, fasting C-peptide, postprandial C-peptide 1h, CRP, history of cataract and Statins treatment showed significant differences among three groups (p&amp;lt;0.05). ANGPTL2 levels in DM, DR without DME, DR with DME groups were 3.55±1.56, 3.68±1.59, 4.45±1.8ng/ml, respectively (P=0.012). In multivariable linear regression, Angplt2 was significantly different among three groups after adjustment for age, gender, BMI, glycosylated hemoglobin, ALT, AST, GGT, and fasting C peptide (P=0.023). Conclusions: Our findings suggest that ANGPTL2 is higher in patients both with DR and DME. Increased level of ANGPTL2 may take part in the progression of diabetic macular edema in type 2 diabetes mellitus. Disclosure N. Zhang: None. Y. An: None. R. Yin: None. D. Zhao: None.

297-LB: Dietary Fructose Increases Plasma Angiopoietin-Like Protein-3 Concentrations in Rhesus Macaques: Prevention with Fish Oil Supplementation

Homozygous loss-of-function ANGPTL3variants are associated with familial combined hypolipidemia, suggesting the dual LPL/EL inhibitor is a promising target for treating atherogenic dyslipidemia. However, nothing is known regarding the dietary regulation of ANGPTL3, including effects of dietary sugar or n-3 fatty acids. We investigated plasma ANGPTL3 concentrations in a rhesus macaque model of high sugar diet-induced dyslipidemia. Animals provided fructose beverages (300 kcal/d) rapidly gain weight (∼10%) and develop insulin resistance and fasting hypertriglyceridemia within 1 month. Fasting plasma ANGPTL3 concentrations increased by 30-40% with fructose consumption after 1 and 3 months (mean±SD in ng/ml; baseline, 60.6±17.4; 1 month, 83.1±25.3; 3 months, 76.9±23.2; both p&amp;lt;0.001 vs. baseline, n=59). Fish oil supplementation (4 g/d) prevents fructose-induced dyslipidemia and completely prevented the increases of ANGPTL3 (-3% vs. +33% over 6 months, p&amp;lt;0.05). Regression modeling to identify lipid/lipoprotein parameters (TG, TC, HDL-C, LDL-C, VLDL-C, APOA1, APOB, APOC3, APOE) explaining variation in ANGPTL3 levels indicated strong correlations with APOC3 at baseline (p=0.002), and APOC3 and APOE after 3 months of fructose (both p&amp;lt;0.05). Regression modeling also examined whether changes (?) of APOC3, APOE, and ANGPTL3 predict ?TG, explaining 41% of variation after 1 month. (R2=0.41, p&amp;lt;0.001). ?APOC3 (B=0.588, p&amp;lt;0.001) and ?ANGPTL3 (B=0.292, p&amp;lt;0.05) were significant predictors in the model. After 3 months, modeling explained 36% of ∆TG (R2=0.36, p&amp;lt;0.001), with all variables contributing significantly (?APOC3, B=0.616, p&amp;lt;0.001; ?ANGPTL3, B=0.245, p&amp;lt;0.05; ?APOE, B= -0.281, p&amp;lt;0.05). Modeling predicted variation of ∆TG before and during fructose consumption (R2=0.294, p=0.033 at baseline; R2=0.438, p&amp;lt;0.001 at 3 months). In summary, these are the first findings reporting effects of diet composition (sugar and n-3 FAs) on circulating ANGPTL3. Disclosure A. Butler: None. J.L. Graham: Research Support; Self; Arrowhead Research, Bristol-Myers Squibb Company, Magnamosis Inc. K.L. Stanhope: None. P.J. Havel: Research Support; Self; Arrowhead Research, Bristol-Myers Squibb Company, Magnamosis Inc. Funding National Institutes of Health

Angiopoietin-like protein-2 and IL-17 Association with Liver Fibrosis in Patients with Chronic Hepatitis B

Hepatitis is an inflammation of the liver with condition can be self-limiting or can progress to fibrosis (scarring), cirrhosis or liver cancer. Angiopoietin-like protein 2 (Angptl2) is a mediator of chronic inflammation that contributes to extracellular matrix remodeling. This study aims to explore the predictive value of Angptl2 as a novel biomarker of liver histology and evaluate the association of Angptl2 and IL-17 with the degree of liver fibrosis. Hepatitis B patients with normal to minimally raised ALT were recruited. Serum Angptl2 and IL-17 levels were detected by using commercial ELISA kit. Liver histology was evaluated by the Ishak scoring system. A highly significant increase of ANGPL2 and IL-17 were observed in sera of chronic hepatitis B patients in comparison to that of control group, while non-significant increases of ANGLP2 and IL-17 with fibrosis stages in chronic hepatitis B were indicated. Angptl2 and IL-17 were found to be increased with increasing degrees of liver fibrosis. This suggests that ANGPL2 and IL-17 may not only induce the inflammation, but also contribute to disease progression of fibrosis and chronicity.

ANGPTL4 gene E40K variation protects against obesity-associated dyslipidemia in participants with obesity.

SummaryObjectiveANGPTL4 inhibits lipoprotein lipase in adipose tissue, regulating plasma triglycerides levels. In persons with obesity plasma ANGPTL4 levels have been positively correlated with body fat mass, TG levels and low HDL. A loss‐of‐function E40K mutation in ANGPTL4 prevents LPL inhibition, resulting in lower TGs and higher HDLc in the general population. Since obesity determines metabolic alterations and consequently is a major risk factor for cardiovascular disease, the aim was to explore if obesity‐related metabolic abnormalities are modified by the ANGPTL4‐E40K mutation.Methods ANGPTL4‐E40K was screened in 1206 Italian participants, of which 863 (71.5%) with obesity. All subjects without diabetes underwent OGTT with calculation of indices of insulin‐sensitivity.ResultsParticipants with obesity carrying the E40K variant had significantly lower TG (p = 0.001) and higher HDLc levels (p = 0.024). Also in the whole population low TGs and high HDLc were confirmed in E40K carriers. In the obese subpopulation it was observed that almost all E40K carriers were within the lowest quartile of TGs (p = 1.1 × 10−9). E40K had no substantial effect of on glucose metabolism. Finally, none of the obese E40K carriers had T2D, and together with the favourable lipid profile, they resemble a metabolically healthy obese (MHO) phenotype, compared to 38% of E40E wild‐type obese that had diabetes and/or dyslipidaemia (p = 0.0106).ConclusionsIn participants with obesity the ANGPTL4‐E40K variant protects against dyslipidemia. The phenotype of obese E40K carriers is that of a patient with obesity without metabolic alterations, similar to the phenotype described as metabolic healthy obesity.

Elevated Levels of Hepatokine Angiopoietin-like 3 Correlate Paradoxically with Hypocholesterolemia and Hemolysis in Sickle Cell Anemia

Sickle cell disease (SCD) is characterized by chronic hemolytic anemia and vaso-occlusion. Hypocholesterolemia has been long recognized in SCD patients, and while it has been postulated that it is secondary to increased erythropoiesis, these mechanisms are not fully understood. Despite their name, angiopoietin-like proteins (ANGPTLs) are family of regulators of angiogenesis unable to bind to receptors classically targeted by angiopoetins. ANGPTL3 and ANGPTL4 are also inhibitors of lipoprotein lipase (LPL), and have become pharmacological targets in the treatment of dyslipidemia. We hypothesized that ANGPTL levels would be abnormal in SCD and could contribute to the understanding of lipid dysregulation. We aimed to determine, compare and correlate the circulating concentrations of ANGPTL3 and ANGPTL4 with hemolysis, lipid metabolism and endothelial dysfunction biomarkers in patients with sickle cell anemia (HbSS), hemoglobin SC disease (HbSC), and healthy individuals (HbAA). Thirty-six HbSS patients (age range 18-55, 21 men), 19 HbSC patients (HbSC) (age range 29-68, 8 men), and 31 HbAA controls (age range 18-66, 23 men) were enrolled in this study. Exclusion criteria were pregnancy, history of blood transfusion or sickle cell pain crisis in the past 3 months. Peripheral blood samples were collected for complete blood counts, biochemistry tests (lactate dehydrogenase [LDH], bilirubin, cholesterol and low and high density fractions, oxidized LDL [oxLDL], hemopexin), and determination of ANGPTL3, ANGPTL4, and soluble vascular cell adhesion molecule-1 (sVCAM-1) levels as marker of endothelial dysfunction. Differences in the intensity of hemolytic anemia between the two groups of SCD were confirmed, as well as decrease in total cholesterol (AA 176±32, SC 141±28 and SS 124±33mg/dL, p<0.0001), HDL (AA 46±11, SC 45±9, SS 37±11mg/dL, p<0.001) and LDL (AA 97±30, SC 76±34 or SS 63±27mg/dL, p<0.0001), as expected. Levels of both ANGPTL3 and ANGPTL4 were significantly higher in both SCD groups than in controls (ANGPTL3: AA 106±30, SC 147±37 and SS 155±58ng/mL, p<0.0001; ANGPTL4: AA 29±23ng/mL, SC 49±52ng/mL, SS 52±39ng/mL, p=0.04). While ANGPTL4 correlated only with LDH and HDL, ANGPTL3 correlated positively with reticulocyte count, LDH, total bilirubin, sVCAM-1, and the degree of LDL oxidation as estimated by oxLDL/LDL ratio, and negatively with hemoglobin, hemopexin, total cholesterol, and LDL levels. Our findings are surprising because the increase in AGPTLs should enhance inhibition of lipoprotein lipase, which is expected to cause hypercholesterolemia. It is therefore possible that hemolytic stimulus is able to override a feedback controlled by the liver between the amount of circulating lipoproteins and the need for LPL inhibition. This may also at least partially support the assumption that the plasma cholesterol pool is consumed for the synthesis of new red blood cells, so inhibition of LPL in this setting could be a compensatory mechanism. Nevertheless, the lack of significant differences between HbSS and HbSC suggests that erythropoietic drive is not the only determining factor. ANGPTL3 has been reported to be elevated in atherosclerosis and in rheumatic disease, so low grade chronic inflammation affecting the endothelium, along with a tendency towards more LDL oxidation could explain the positive correlation between sVCAM-1 and ANGPTL3. It is most remarkable that only ANGPTL3 correlated with hemolysis. ANGPTL3 is exclusively produced by the liver, while ANGPTL4 can be synthesized by adipose tissue, muscle, kidney, heart and thyroid, suggesting the stimulus for its overproduction generated by hemolysis is mostly sensed by hepatocytes. Considering the negative correlation with hemopexin, one possibility is that heme-hemopexin complexes taken up by liver cells and subsequent heme oxygenase induction may be involved in upregulation of ANGPTL3. Our data reveal that the production of lipoprotein lipase inhibitors is dysregulated in SCD-associated hypocholesterolemia, with a paradoxical increase in ANGPTLs which is most likely due to a liver response to hemolysis. Further studies should determine whether this mechanism is compensatory or driven by excessive heme production. DisclosuresFertrin:Alexion Pharmaceuticals Brasil: Speakers Bureau; Apopharma Inc.: Honoraria.

ChREBP Reciprocally Regulates Liver and Plasma Triacylglycerol Levels in Different Manners.

Carbohydrate response element-binding protein (ChREBP) has an important role in the carbohydrate-mediated regulation of hepatic de novo lipogenesis, but the mechanism for how it regulates plasma triacylglycerol (TAG) levels has not been established. This study aimed to clarify the role of ChREBP in regulation of plasma TAG levels. We analyzed the metabolic changes in mice infected with an adenovirus expressing ChREBP Δ196 (Ad-ChREBP). Compared with adenovirus harboring green fluorescent protein infected mice, Ad-ChREBP-infected mice had higher plasma free fatty acid levels and paradoxically lower plasma 3-hydroxybutyrate levels through decreased fatty acid oxidation, rather than ketogenesis. Consistent with their hepatomegaly and increased lipogenic gene expression, the liver TAG contents were much higher. Regarding lipid composition, C16:0 was much lower and C18:1n-9 was much higher, compatible with increased stearoyl CoA desaturase-1 and ELOVL fatty acid elongase 6 expression. Furthermore, Ad-ChREBP-infected mice had decreased plasma TAG and very low density lipoprotein (VLDL)-TAG levels, consistent with decreased Angiopoietin-like protein 3 (Angptl3) and increased fibroblast growth factor (Fgf21) mRNA and protein levels. Finally, Ad-ChREBP infection increased white adipose tissue Ucp1 mRNA levels with increased plasma Fgf21 levels. Because Fgf21 and Angptl3 are known to activate and suppress lipolysis in adipose tissues and oxidative tissues, ChREBP appears to regulate plasma TAG levels by modulating Fgf21 and Angptl3 levels. Thus, ChREBP overexpression led to dissociation of hepatic steatosis from hyperlipidemia.

Enhanced ANGPTL2 expression in adipose tissues and its association with insulin resistance in obese women

Angiopoietin-like protein 2 has been proposed to be a key mediator linking obesity and insulin resistance. However, no detailed study of ANGPTL2 expression in human adipose tissues has yet been reported. To investigate the pattern and regulation of ANGPTL2 expression in human adipose tissues in obesity and its related diseases, we recruited 32 non-diabetic and 13 type 2 diabetic obese women and 32 normal-weight women. ANGPTL2 mRNA was expressed at a similar level in visceral and subcutaneous adipose tissues. Adipose tissue ANGPTL2 mRNA was much higher in obese patients. Adipose tissue ANGPTL2 mRNA and serum ANGPTL2 levels showed strong associations with metabolic parameters associated with insulin resistance. In adipose tissue, ANGPTL2 mRNA was closely correlated with the expression of genes involved in inflammation and ER stress. ANGPTL2 mRNA was principally expressed in adipocytes, and its expression was markedly higher in the adipocyte but non-adipocyte fraction of obese adipose tissues. Culture of human adipocytes under conditions mimicking the microenvironment of obese adipose tissue (especially, increased ER stress) stimulated ANGPTL2 gene expression and secretion. In addition, co-culture of adipocytes and macrophages suggested that ANGPTL2 excessively produced by adipocytes, may contribute inflammation and remodeling in obese adipose tissues, thereby promoting insulin resistance.

Increased Angiopoietin Like Proteins 4 (ANGPTL4) Is Associated with Higher Concentration of LDL-Triglycerides in Type 2 Diabetes

Background/Aims: Diabetic dyslipidemia is typically characterized by an increase in plasma triglycerides (TG), a concomitant increase in small dense (sd) low density lipoprotein (LDL) and atherogenic LDL-TG. Angiopoietin like protein 4 (ANGPTL4) is well established regulators of plasma TG level through regulating the activity of lipoprotein lipase. Plasma level and association between ANGPTL4 and sdLDL or LDL-TG is not well established in human subjects. We aimed to examine the level of ANGPTL4 and investigate the association between ANGPTL4 with sdLDL-C and LDL-TG in type 2 diabetes (T2D). Methods: 250 (M176/F 74) Japanese diabetic patients and 9 of healthy controls (Controls) were enrolled in this study. SdLDL-C and LDL-TG were measured by homogeneous assays. ANGPTL3 and ANGPTL4 protein levels were measured by ELISA. Results: As compared with Controls, plasma ANGPTL3, ANGPTL4, sdLDL-C and LDL-TG levels were increased in T2D. ANGPTL3 was not collated with sdLDL-C or LDL-TG. ANGPTL4 was positively correlated with HbA1c(r=0.15, p=0.019), TG(r=0.15, p=0.018)and LDL-TG(r=0.17,p=0.008), whereas ANGPTL4 was not collated with sdLDL-C. Furthermore, ANGPTL4 was also significantly associated with LDL-TG/LDL-C ratio (r=0.15, p=0.022) and LDL-TG/apoB ratio (r=0.18, p=0.009). Conclusions: The ANGPTL4 level was increased in T2D and associated with atherogenic higher LDL-TG levels. ANGPTL4 may play a role in modulating lipid metabolism in LDL particles. Disclosure H. Nagaike: None. T. Hayashi: None. N. Nakanishi: None. M. Ohara: None. T. Yamamoto: None. T. Fukui: None. T. Hirano: Speaker's Bureau; Self; Novo Nordisk Inc., AstraZeneca.

Serum Levels of Angiopoietin-Like Protein 2 and Obestatin in Iranian Women with Polycystic Ovary Syndrome and Normal Body Mass Index.

Background: Polycystic ovary syndrome (PCOS) is a common endocrine disease in women of reproduction age and a major cause of anovulatory infertility. Insulin resistance plays an important role in the development and durability of this disorder. ANGPTL2 is known as an inflammatory mediator derived from adipose tissue that links obesity to systemic insulin resistance, and obestatin has been identified as a hormone associated with insulin resistance that suppresses food reabsorption, inhibits gastric emptying and decreases weight gain. The aim of this study was to evaluate serum levels of ANGPTL2 and obestatin in PCOS women with normal body mass index (BMI). Methods: In this case-control study, 26 PCOS women based on the Rotterdam 2003 diagnostic criteria as the case group and 26 women with normal menstrual cycles as the control group were enrolled. Serum levels of ANGPTL2, obestatin, insulin and other hormone factors related with PCOS were measured by ELISA method and biochemical parameters were measured by an autoanalyzer. Data were analyzed by independent samples-T test, Chi Square, Correlation and a single sample Kolmogrov–Smirnov test using SPSS software, version 16. Results: There were no significant variations in the amount of ANGPTL2, obestatin, cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein, cholesterol, creatinine and dehydroepiandrosterone-sulfate between the two groups. There were significant increases in serum levels of fasting blood sugar (p = 0.01), insulin (p = 0.04), homeostasis model assessments of insulin resistance (p = 0.04), testosterone (p = 0.02), luteinizing hormone (p = 0.004), luteinizing hormone/follicle stimulating hormone (p = 0.006) and prolactin (p = 0.04) in case group compared to the control group. A significant positive correlation was observed between ANGPTL2 and insulin (p = 0.02), HOMA-IR (p = 0.01) and, on the other hand, a significant negative correlation was observed between obestatin and insulin (p = 0.01), HOMA-IR (p = 0.008) in PCOS group. Conclusions: In this study, no significant variations were observed in serum levels of ANGPTL2 and obestatin in PCOS women with normal BMI.