Angiopoietin-Like 3 (ANGPTL3) and Atherosclerosis: Lipid and Non-Lipid Related Effects

Triglyceride-rich lipoproteins and cardiovascular diseases

The global prevalence of cardiovascular diseases (CVD) continues to rise steadily, making it a leading cause of mortality worldwide. Atherosclerosis (AS) serves as a primary driver of these conditions, commencing silently at an early age and culminating in adverse cardiovascular events that severely impact patients' quality of life or lead to fatality. Dyslipidemia, particularly elevated levels of low-density lipoprotein cholesterol (LDL-C), plays a pivotal role in AS pathogenesis as an independent risk factor. Research indicates that abnormal LDL-C accumulation within arterial walls acts as a crucial trigger for atherosclerotic plaque formation. As the disease progresses, plaque accumulation may rupture or dislodge, resulting in thrombus formation and complete blood supply obstruction, ultimately causing myocardial infarction, cerebral infarction, and other common adverse cardiovascular events. Despite adequate pharmacologic therapy targeting LDL-C reduction, patients with cardiometabolic abnormalities remain at high risk for disease recurrence, highlighting the importance of addressing lipid risk factors beyond LDL-C. Recent attention has focused on the causal relationship between triglycerides, triglyceride-rich lipoproteins (TRLs), and their remnants in AS risk. Genetic, epidemiologic, and clinical studies suggest a causal relationship between TRLs and their remnants and the increased risk of AS, and this dyslipidemia may be an independent risk factor for adverse cardiovascular events. Particularly in patients with obesity, metabolic syndrome, diabetes, and chronic kidney disease, disordered TRLs and its remnants levels significantly increase the risk of atherosclerosis and cardiovascular disease development. Accumulation of over-synthesized TRLs in plasma, impaired function of enzymes involved in TRLs lipolysis, and impaired hepatic clearance of cholesterol-rich TRLs remnants can lead to arterial deposition of TRLs and its remnants, promoting foam cell formation and arterial wall inflammation. Therefore, understanding the pathogenesis of TRLs-induced AS and targeting it therapeutically could slow or impede AS progression, thereby reducing cardiovascular disease morbidity and mortality, particularly coronary atherosclerotic heart disease.

Zebrafish ApoB-Containing Lipoprotein Metabolism: A Closer Look

Zebrafish have become a powerful model of mammalian lipoprotein metabolism and lipid cell biology. Most key proteins involved in lipid metabolism, including cholesteryl ester transfer protein, are conserved in zebrafish. Consequently, zebrafish exhibit a human-like lipoprotein profile. Zebrafish with mutations in genes linked to human metabolic diseases often mimic the human phenotype. Zebrafish larvae develop rapidly and externally around the maternally deposited yolk. Recent work revealed that any disturbance of lipoprotein formation leads to the accumulation of cytoplasmic lipid droplets and an opaque yolk, providing a visible phenotype to investigate disturbances of the lipoprotein pathway, already leading to discoveries in MTTP (microsomal triglyceride transfer protein) and ApoB (apolipoprotein B). By 5 days of development, the digestive system is functional, making it possible to study fluorescently labeled lipid uptake in the transparent larvae. These and other approaches enabled the first in vivo description of the STAB (stabilin) receptors, showing lipoprotein uptake in endothelial cells. Various zebrafish models have been developed to mimic human diseases by mutating genes known to influence lipoproteins (eg, ldlra, apoC2). This review aims to discuss the most recent research in the zebrafish ApoB-containing lipoprotein and lipid metabolism field. We also summarize new insights into lipid processing within the yolk cell and how changes in lipid flux alter yolk opacity. This curious new finding, coupled with the development of several techniques, can be deployed to identify new players in lipoprotein research directly relevant to human disease.

Association of a genetic variant in angiopoietin-like 3 with serum HDL-C and risk of cardiovascular disease: A study of the MASHAD cohort over 6 years

BACKGROUND

Loss-of-function (LOF) variants of the angiopoietin-like 3 (ANGPTL3) gene are reported to be associated with serum triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) concentrations and thereby affect the risk of cardiovascular disease (CVD).

OBJECTIVE

In the present study, we examined the association of rs10789117 in the ANGPTL 3 gene locus and the risk of CVD in the group of people who were part of the Mashhad-Stroke and Heart-Atherosclerotic-Disorders (MASHAD) cohort.

METHODS

One thousand and two healthy individuals enrolled in this study of whom 849 subjects were healthy and 153 subjects developed CVD outcomes after 6 years of follow-up. After a 12-h overnight fasting, 20 mL of blood samples were collected for the measurement of fasting blood glucose and lipid profile. DNA was extracted, and the Tetra-ARMS PCR (amplification refractory mutation system) was used for genotyping of rs10789117 in the ANGPTL3 gene. The genotype frequencies of the variant of rs10789117 in the ANGPTL3 gene were estimated using χ2 tests. Eventually, the statistical analysis was done by SPSS version 20.

RESULTS

Individuals with AC/CC genotypes (rs10789117) were found to have to greater risk of CVD events compared to AA genotype (OR = 1.43, 95%CI = 1.01-2.02, p = 0.041). There was a 1.3-fold increase in cardiovascular events in individuals carrying the C allele of rs10789117 variant compared to non-carriers (OR = 1.32, 95%CI = 1.06-1.72, p value = 0.038). There were significant differences between different genotypes for serum triglyceride levels within the control group, but this difference was not significant in the group with CVD. Moreover, there was a significant association between CC genotype and CVD risk in the individuals with a normal serum HDL-C.

CONCLUSION

We have found that a rs10789117 C>A in ANGPTL3 gene polymorphism was associated with incident CVD events, and this may be of value as a risk stratification biomarker in CVD in the Iranian population.

Gene Silencing of Angiopoietin-like 3 (ANGPTL3) Induced De Novo Lipogenesis and Lipid Accumulation in Huh7 Cell Line

Angiopoietin-like 3 (ANGPTL3) is a hepatokine acting as a negative regulator of lipoprotein lipase (LPL). Vupanorsen, an ANGPTL3 directed antisense oligonucleotide, showed an unexpected increase in liver fat content in humans. Here, we investigated the molecular mechanism linking ANGPTL3 silencing to hepatocyte fat accumulation. Human hepatocarcinoma Huh7 cells were treated with small interfering RNA (siRNA) directed to ANGPTL3, human recombinant ANGPTL3 (recANGPTL3), or their combination. Using Western blot, Oil Red-O, biochemical assays, and ELISA, we analyzed the expression of genes and proteins involved in lipid metabolism. Oil Red-O staining demonstrated that lipid content increased after 48 h of ANGPTL3 silencing (5.89 ± 0.33 fold), incubation with recANGPTL3 (4.08 ± 0.35 fold), or their combination (8.56 ± 0.18 fold), compared to untreated cells. This effect was also confirmed in Huh7-LX2 spheroids. A total of 48 h of ANGPTL3 silencing induced the expression of genes involved in the de novo lipogenesis, such as fatty acid synthase, stearoyl-CoA desaturase, ATP citrate lyase, and Acetyl-Coenzyme A Carboxylase 1 together with the proprotein convertase subtilisin/kexin 9 (PCSK9). Time-course experiments revealed that 6 h post transfection with ANGPTL3-siRNA, the cholesterol esterification by Acyl-coenzyme A cholesterol acyltransferase (ACAT) was reduced, as well as total cholesterol content, while an opposite effect was observed at 48 h. Under the same experimental conditions, no differences in secreted apoB and PCSK9 were observed. Since PCSK9 was altered by the treatment, we tested a possible co-regulation between the two genes. The effect of ANGPTL3-siRNA on the expression of genes involved in the de novo lipogenesis was not counteracted by gene silencing of PCSK9. In conclusion, our in vitro study suggests that ANGPTL3 silencing determines lipid accumulation in Huh7 cells by inducing the de novo lipogenesis independently from PCSK9.

Serum Angiopoietin-like Protein 3 Levels Are Associated with Endothelial Function in Patients with Maintenance Hemodialysis

Angiopoietin-like protein 3 (ANGPTL3) plays an important role in lipid and lipoprotein trafficking and metabolism and is positively correlated with cardiovascular disease. Our objective was to evaluate the association between serum ANGPTL3 levels and endothelial function in patients on maintenance hemodialysis (MHD). We enrolled 116 patients on MHD and obtained their blood test results from their medical records. Using a noninvasive digital thermal monitor, we determined the vascular reactivity index (VRI) as a measure of endothelial function. Serum ANGPTL3 concentration was measured by a commercial-enzyme-linked immunosorbent assay. Vascular reactivity was classified as poor in 17 (14.7%) patients, intermediate (1.0 ≤ VRI < 2.0) in 50 (43.1%) patients, and high (VRI ≥ 2.0) in 49 (42.2%) patients. Serum levels of ANGPTL3 (p < 0.001) and alkaline phosphatase (ALP, p = 0.025) increased significantly as the VRI decreased. The log-transformed serum ALP (log-ALP, r = -0.187, p = 0.045) and log-ANGPTL3 (r = -0.319, p < 0.001) showed a negative correlation with the VRI on univariate linear regression analysis. A significant negative correlation was found between log-ANGPTL3 and VRI (p < 0.001) on multivariate stepwise linear regression analysis. The findings of our investigation showed that, in patients with MHD, the ANGPTL3 concentration had a negative correlation with the VRI.

Human gain-of-function variants in HNF1A confer protection from diabetes but independently increase hepatic secretion of atherogenic lipoproteins

Loss-of-function mutations in hepatocyte nuclear factor 1A (HNF1A) are known to cause rare forms of diabetes and alter hepatic physiology through unclear mechanisms. In the general population, 1:100 individuals carry a rare, protein-coding HNF1A variant, most of unknown functional consequence. To characterize the full allelic series, we performed deep mutational scanning of 11,970 protein-coding HNF1A variants in human hepatocytes and clinical correlation with 553,246 exome-sequenced individuals. Surprisingly, we found that ∼1:5 rare protein-coding HNF1A variants in the general population cause molecular gain of function (GOF), increasing the transcriptional activity of HNF1A by up to 50% and conferring protection from type 2 diabetes (odds ratio [OR] = 0.77, p = 0.007). Increased hepatic expression of HNF1A promoted a pro-atherogenic serum profile mediated in part by enhanced transcription of risk genes including ANGPTL3 and PCSK9. In summary, ∼1:300 individuals carry a GOF variant in HNF1A that protects carriers from diabetes but enhances hepatic secretion of atherogenic lipoproteins.

Evaluation of rs1748195 ANGPTL3 gene polymorphism in patients with angiographic coronary artery disease compared to healthy individuals

SUBJECT

The Angiopoietin-like 3 (ANGPTL3) gene has been reported to be associated with cardiovascular risk. This study is designed to compare the genetic variant (rs1748195) of the ANGPTL3 gene and the presence of a coronary artery occlusion of >50% in Iranian nation.

METHOD

In this study, 184 patients underwent angiography and 317 healthy individuals were evaluated for polymorphism of rs1748195 the ANGPTL3 gene using Tetra-ARMs PCR. Coronary patients who experience angiography were categorized into two groups: 54 patients who had an angiography indication for the first time and coronary occlusion was <50% (Angio-) and 134 patients who formerly underwent coronary stent implanting at least 1 month before with coronary occlusion of ≥50% that again have an angiography indication (Angio+). In addition, individuals with angio+ are categorized in two groups: (1) non-in-stent restenosis (NISR); patient with a patent stent (N = 92). (2) in-stent restenosis (ISR); in-stent stenosis >50% (N = 42).

RESULT

The fundamental of characteristics of our study design population was categorized based on undergoing angiography or not. In the present study, we investigated that the CC genotype, and also the A allele corresponding to rs1748195 at the ANGPTL3 gene loci, was associated with negative angiogram and directly related to the risk of coronary occlusion >50%. In contrast, this result was not significant in genotypes of ANGPTL3 between non-ISR and ISR groups.

CONCLUSION

The outcomes of this study showed that rs1748195 polymorphism at the ANGPTL3 gene loci is associated with an elevated risk for the existence of a coronary occlusion of >50%.

Angiopoietin-like proteins inhibitors: New horizons in the treatment of atherogenic dyslipidemia and familial hypercholesterolemia

Angiopoietin-like proteins (ANGPTL) are involved in the regulation of numerous physiological and biochemical processes. ANGPTL3, 4 and 8, which are involved in the regulation of lipoprotein metabolism, are particularly important. ANGPTL3, 4 and 8 have been shown to regulate triglyceride availability depending on the nutritional status of the body. In addition, a deficiency of these proteins has been found to cause hypolipidemia (reduction of all lipid fractions). Increases in ANGPTL3, 4 and 8 appear to be associated with cardiovascular risk. Animal studies indicate that the use of ANGPTL3 (evinacumab) inhibitors significantly reduces plasma total cholesterol, triglycerides and low-density lipoprotein concentrations. The use of evinacumab in clinical trials also led to the normalization of plasma lipid concentrations in patients with atherogenic dyslipidemia and homozygous familial hypercholesterolemia. The results of these studies indicate that evinacumab may in the future be used in the treatment of lipid disorders, especially those with hypertriglyceridemia.

Association of the ANGPTL3 gene polymorphisms and haplotypes with cardiovascular diseases in Birjand longitudinal aging study (BLAS)

Subject

Cardiovascular disease is now well established as an interaction between genetic and environmental components. Newly identified single nucleotide polymorphisms of angiopoietin-like 3 (ANGPTL3) influence lipid concentrations and risk of coronary artery disease. The current study aimed to determine the association between ANGPTL3 gene variants with incident CVDs in elderly population of the Birjand longitudinal aging study (BLAS).

Method

Totally, 360 individuals were recruited in baseline of BLAS including 128 patients with CVD and 153 control subjects. DNA extraction of samples and genotyping were performed by Tetra-ARMS PCR (amplification refractory mutation system polymerase chain reaction). The association between three polymorphisms of ANGPTL3 gene (rs1748195, rs11207997, and rs10789117 variants) with CVD and its risk factors were evaluated using multivariate analysis.

Results

Univariate and multiple analyses showed that individuals carrying the GG genotype of rs1748195 and those carrying the TT genotype of rs11207997 directly increased the risk of CVD. CC genotype of rs1748195 and rs11207997 polymorphisms had a significant negative relationship with the disease. In addition, the findings of this study indicate a significant difference in LDL, HDL, cholesterol levels between different genotypes of the rs1748195 and rs10789117 in the healthy group. Individuals with haplotypes CAC, CCC and CCT showed a significant positive relationship with CVD, CVA, AMI and CHD. As well as haplotype was associated with a 1.7-fold increase in risk of CVA, AMI, and CHD.

Conclusion

We found that polymorphism of ANGPTL3 gene might support to identify individuals with a cardiometabolic and genetic disorders susceptibility. Three haplotypes CAC, CCC and CCT associated with CVD, CVA, AMI and CHD were reported.

Targeting ANGPTL3 by GalNAc-conjugated siRNA ANGsiR10 lowers blood lipids with long-lasting and potent efficacy in mice and monkeys

Angiopoietin-like protein 3 (ANGPTL3) is an important regulator of lipoproteins by inhibiting both lipoprotein and endothelial lipases. It has been intensively investigated as a drug target for the treatment of dyslipidemia. In the present study, a modified small interfering RNA (siRNA) conjugated with GalNAc ANGsiR10 was characterized by in vivo and in vitro studies for its effect on ANGPTL3 silencing, the reduction of plasma triglycerides (TGs), and cholesterol levels in disease models. The results showed that ANGsiR10 displayed a significant and long-lasting efficacy in reducing blood TG and cholesterol levels in both mice and monkeys. Remarkably, the maximal reductions of plasma TG levels in the hApoC3-Tg mice, a model with high TG levels, and the spontaneous dyslipidemia model of rhesus monkey were 96.3% and 67.7%, respectively, after a single dose of ANGsiR10, with long-lasting effects up to 15 weeks. The cholesterol levels were also reduced in response to treatment, especially the non-HDL-c level, without altering the ApoA/ApoB ratio. This study showed that ANGsiR10 is effective in treating dyslipidemia and is worth further development.

Serum biomarkers, including nitric oxide metabolites (NOx), for prognosis of cardiovascular death and acute myocardial infarction in an ESSE-RF case-control cohort with 6.5-year follow up

The present case-control study aimed to assess associations of routine and experimental biomarkers with risk for cardiovascular death and acute myocardial infarction (AMI) in a cohort recruited from the multicenter study "Cardiovascular Epidemiology in Russian Federation" (ESSE-RF) to identify experimental biomarkers potentially suitable for expanded evaluation. A total of 222 subjects included cardiovascular death (N = 48) and AMI cases (N = 63) during 6.5-year follow up and matched healthy controls. Seven routine and eight experimental biomarkers were assayed to analyze associations with outcomes using logistic and Cox proportional hazard regressions. Elevated levels of cardiac troponin I (cTnI), C-reactive protein (CRP), and nitric oxide metabolites (NOx) were independently associated (P < 0.001) with higher risk of cardiovascular death (estimated hazard ratio (eHR) = 1.83-3.74). Elevated levels of NOx and cTnI were independently (P < 0.001) associated with higher risk of nonfatal AMI (eHRs = 1.78-2.67). Elevated levels of angiopoietin-like protein 3 (ANGPTL3) were independently associated (P < 0.001) with lower risk of cardiovascular death (eHRs 0.09-0.16) and higher risk of nonfatal AMI (eHR = 2.07; P = 0.01). These results indicated that subsequent expanded validation should focus on predictive impact of cTnI, NOx, CRP, and ANGPTL3 to develop nationwide recommendations for individual stratification of patients with cardiovascular risks.

Angiopoietin-Like Protein 3 (ANGPTL3) Inhibitors in the Management of Refractory Hypercholesterolemia

Cardiovascular disease (CVD) is the most common cause of death in a global scale and significantly depends on the elevated plasma levels of low-density lipoprotein cholesterol (LDL-C) and the subsequent formation of atherosclerotic plaques. While physicians have several LDL-C-lowering agents with diverse mechanisms of action, including statins, ezetimibe, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors and inclisiran, angiopoietin-like protein 3 (ANGPTL3) inhibitors have recently emerged as a powerful addition in the armamentarium of lipid-lowering strategies, especially for patients with refractory hypercholesterolemia, as in the case of patients with homozygous familial hypercholesterolemia (HoFH). ANGPTL3 protein is a glycoprotein secreted by liver cells that is implicated in the metabolism of lipids along with other ANGPTL proteins. These proteins inhibit lipoprotein lipase (LPL) and endothelial lipase (EL) in tissues. Loss-of-function mutations affecting the gene encoding ANGPTL3 are linked with lower total cholesterol, LDL-C, and triglyceride (TG) levels. Evinacumab is a monoclonal antibody that targets, binds to, and pharmacologically inhibits ANGPTL3, which was recently approved by the United States Food and Drug Administration (FDA) as a complementary agent to other LDL-C lowering regimens for patients aged 12 or older with HoFH, based on clinical trial evidence that confirmed its safety and efficacy in those patients. Antisense oligonucleotides (ASOs) also represent an interesting class of agents that target and inhibit the mRNA derived from the transcription of ANGPTL3 gene. This review aims to present and discuss the current clinical and scientific data pertaining to the role of ANGPTL3 inhibitors, a novel lipid-modifying class of agents capable of reducing LDL-C levels via a mechanism independent of LDL receptors.

The Potential Diagnostic Value of Immune-Related Genes in Interstitial Fibrosis and Tubular Atrophy after Kidney Transplantation

Background

Inflammation within areas of interstitial fibrosis and tubular atrophy (IF/TA) is associated with kidney allograft failure. The aim of this study was to reveal new diagnostic markers of IF/TA based on bioinformatics analysis.

Methods

Raw data of IF/TA samples after kidney transplantation and control samples after kidney transplantation were extracted from the Gene Expression Omnibus (GEO) database (GSE76882 and GSE120495 datasets), and genes that were differentially expressed between the two groups (DEGs) were screened. Gene Set Enrichment Analysis (GSEA), ESTIMATE and single sample GSEA (ssGSEA), least absolute shrinkage and selection operator (LASSO) regression analysis, and competing endogenous RNA (ceRNA) network were used to analyze the data.

Results

The results of GSEA revealed that multiple immune-related pathways were enriched in the IF/TA group, and subsequent immune landscape analysis also showed that the IF/TA group had higher immune and stromal scores and up to 15 types of immune cells occupied them, such as B cells, cytotoxic cells, and T cells. LASSO regression analysis selected 6 (including ANGPTL3, APOH, LTF, FCGR2B, HLA-DQA2, and EGF) out of 14 DE-IRGs as diagnostic genes to construct a diagnostic model. Then, receiver operating characteristic (ROC) curve analysis showed the powerful diagnostic value of the model, and the area under the curve (AUC) of a single diagnostic gene was greater than 0.75. The results of ingenuity pathway analysis (IPA) also indicated that DEGs were involved in the immune system and kidney disease-related pathways. Finally, we found multiple miRNAs that could regulate diagnostic genes from the ceRNA network.

Conclusion

This study identified 6 IF/TA-related genes, which might be used as a new diagnosis model in the clinical practice.

The Functional Role of Lipoproteins in Atherosclerosis: Novel Directions for Diagnosis and Targeting Therapy

Dyslipidemia, characterized by a high level of lipids (cholesterol, triglycerides, or both), can increase the risk of developing and progressing atherosclerosis. As atherosclerosis progresses, the number and severity of aterial plagues increases with greater risk of myocardial infarction, a major contributor to cardiovascular mortality. Atherosclerosis progresses in four phases, namely endothelial dysfunction, fatty streak formation, lesion progression and plaque rupture, and eventually thrombosis and arterial obstruction. With greater understanding of the pathological processes underlying atherosclerosis, researchers have identified that lipoproteins play a significant role in the development of atherosclerosis. In particular, apolipoprotein B (apoB)-containing lipoproteins have been shown to associate with atherosclerosis. Oxidized low-density lipoproteins (ox-LDLs) also contribute to the progression of atherosclerosis whereas high-density lipoproteins (HDL) contribute to the removal of cholesterol from macrophages thereby inhibiting the formation of foam cells. Given these known associations, lipoproteins may have potential as biomarkers for predicting risk associated with atherosclerotic plaques or may be targets as novel therapeutic agents. As such, the rapid development of drugs targeting lipoprotein metabolism may lead to novel treatments for atherosclerosis. A comprehensive review of lipoprotein function and their role in atherosclerosis, along with the latest development of lipoprotein targeted treatment, is timely. This review focuses on the functions of different lipoproteins and their involvement in atherosclerosis. Further, diagnostic and therapeutic potential are highlighted giving insight into novel lipoprotein-targetted approaches to treat atherosclerosis.

Angiopoietin-like 3 (ANGPTL3) drives cell proliferation, migration and angiogenesis in cervical cancer via binding to integrin alpha v beta 3

Angiopoietin-like 3 (ANGPTL3) has been uncovered to play an oncogenic role in several kinds of human malignancies. Nevertheless, whether ANGPTL3 functions in cervical cancer (CC) has not yet been reported. This paper is intended to explore the impact of ANGPTL3 on CC cells and elucidate the potential mechanism. In this study, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were performed to analyze the ANGPTL3 expression. Western blot was also performed to examine integrin αvβ3 protein level. Cell proliferation was evaluated by MTT assay, EdU staining and Western blot analysis. In addition, the migratory and invasive abilities of cells were, respectively, estimated by wound healing and transwell assays. Tube formation assay was performed to determine endothelial cell angiogenesis. Levels of vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor 2 (VEGFR2) were measured by ELISA. As a result, ANGPTL3 expression was significantly higher in CC cells relative to that in normal cervical cells. Silencing of ANGPTL3 suppressed cell proliferation, migration and invasion. Besides, downregulation of ANGPTL3 inhibited human umbilical vein endothelial cell (HUVEC) angiogenesis and repressed protein level of integrin alpha v beta 3 (αvβ3). Upregulation of αvβ3 offsets the inhibitory effect of ANGPTL3 on proliferation, migration and invasion in CC cells. Upregulated expression of αvβ3 promoted blood vessel formation and secretions of VEGF and VEGFR2. In conclusion, ANGPTL3 silencing may serve as a tumor suppressor in CC through integrin αvβ3, which provides a potentially novel therapeutic target for patients with CC.

Trends in Antidiabetic Drug Discovery: FDA Approved Drugs, New Drugs in Clinical Trials and Global Sales

Type 2 diabetes mellitus (T2DM) continues to be a substantial medical problem due to its increasing global prevalence and because chronic hyperglycemic states are closely linked with obesity, liver disease and several cardiovascular diseases. Since the early discovery of insulin, numerous antihyperglycemic drug therapies to treat diabetes have been approved, and also discontinued, by the United States Food and Drug Administration (FDA). To provide an up-to-date account of the current trends of antidiabetic pharmaceuticals, this review offers a comprehensive analysis of the main classes of antihyperglycemic compounds and their mechanisms: insulin types, biguanides, sulfonylureas, meglitinides (glinides), alpha-glucosidase inhibitors (AGIs), thiazolidinediones (TZD), incretin-dependent therapies, sodium-glucose cotransporter type 2 (SGLT2) inhibitors and combinations thereof. The number of therapeutic alternatives to treat T2DM are increasing and now there are nearly 60 drugs approved by the FDA. Beyond this there are nearly 100 additional antidiabetic agents being evaluated in clinical trials. In addition to the standard treatments of insulin therapy and metformin, there are new drug combinations, e.g., containing metformin, SGLT2 inhibitors and dipeptidyl peptidase-4 (DPP4) inhibitors, that have gained substantial use during the last decade. Furthermore, there are several interesting alternatives, such as lobeglitazone, efpeglenatide and tirzepatide, in ongoing clinical trials. Modern drugs, such as glucagon-like peptide-1 (GLP-1) receptor agonists, DPP4 inhibitors and SGLT2 inhibitors have gained popularity on the pharmaceutical market, while less expensive over the counter alternatives are increasing in developing economies. The large heterogeneity of T2DM is also creating a push towards more personalized and accessible treatments. We describe several interesting alternatives in ongoing clinical trials, which may help to achieve this in the near future.

Impact of oral lipid and glucose tolerance tests on the postprandial concentrations of angiopoietin-like proteins (Angptl) 3 and 4

Background

The postprandial regulation of angiopoietin-like proteins (Angptls) and their expression in adipocytes is poorly characterized.

Objective

Circulating Angptl3 and 4 were analyzed in healthy individuals undergoing either an oral lipid tolerance test (OLTT; n = 98) or an oral glucose tolerance test (OGTT; n = 99). Venous blood was drawn after 0, 2, 4, and 6 h during OLTT and after 0, 1, and 2 h during OGTT. Anthropometric and laboratory parameters were assessed and concentrations of Angptls were quantified by enzyme-linked immunosorbent assay. Angptl gene expression in 3T3-L1 adipocytes and in murine adipose tissues and cellular fractions was analyzed by quantitative real-time PCR.

Results

Angptl3 concentrations significantly decreased while Angptl4 levels continuously increased during OLTT. Both proteins remained unaffected during OGTT. Angptl3 and Angptl4 were expressed in murine subcutaneous and visceral AT with higher mRNA levels in mature adipocytes when compared to the stroma-vascular cell fraction. Both proteins were strongly induced during 3T3-L1 adipocyte differentiation and they were unresponsive to glucose in mature fat cells. Adipocyte Angptl3 (but not Angptl4) mRNA expression was inhibited by the polyunsaturated fatty acids arachidonic acid and docosahexaenoic acid, whereas nine types of dietary fatty acids remained without any effect.

Conclusions

There is evidence of short-time regulation of Angptl3/4 levels upon metabolic stress. Angptl4 expression is high and Angptl3 expression is low in AT and restricted mainly to mature adipocytes without any differences concerning fat compartments. Whereas dietary fatty acids and glucose are without any effect, omega-3/-6-polyunsaturated fatty acids inhibited Anptl3 expression in adipocytes.

Angiopoietin-like proteins 3, 4 and 8 are linked to cardiovascular function in naïve sub-clinical and overt hypothyroid patients receiving levothyroxine therapy

OBJECTIVE

Angiopoietin-like proteins (ANGPTL) 3, 4 and 8 are upcoming cardiovascular biomarkers. Experimental studies showed that thyroid hormones altered their levels. We assessed ANGPTL3, 4 and 8 as predictors of cardiovascular functions among naïve subclinical and naïve overt hypothyroidism (SCH and OH) and altered ANGPTL levels with levothyroxine replacement (LT4) and their association with improved cardiovascular risk factors and cardiovascular function.

DESIGN AND METHODS

The study was a prospective follow-up study that assessed ANGPTL3, 4 and 8 levels, vascular status (flow-mediated dilation% of brachial artery (FMD%), carotid intima-media thickness (CIMT), aortic stiffness index (ASI)), left ventricle (LV) parameters (ejection fraction (EF), myocardial performance index (MPI), and LV mass), well-known cardiovascular risk factors and homeostatic model for the assessment of insulin resistance, at two time points, that is, among naïve SCH, naïve OH, and healthy subjects groups; and at 6 months after achieving the euthyroid state with LT4 by calculating their increased or decreased delta changes (∆↑ or ∆↓) in longitudinal arm among LT4-hypothyroid groups.

RESULTS

Significantly elevated levels of ANGPTL3, 4 and 8 among hypothyroid groups than the healthy subjects were reduced with LT4. Multivariate analysis revealed ANGPTLs as independent predictors of cardiovascular functions and the contributors for ANGPTL level included ANGPTL3 and 4 for impaired FMD%, and ANGPTL8 for LV mass among naïve SCH; ANGPTL3 for EF% and ANGPTL8 for CIMT in naïve OH; ∆↓ANGPTL3 for ∆↓ASI meanwhile ∆↑freeT4 for ∆↓ANGPTL3, ∆↓fasting glucose, ∆↓triglyceride, and ∆↓thyroid peroxidase antibody for ∆↓ANGPTL4 among LT4-SCH. ∆↓ANGPTL4 for ∆↓MPI and ∆↓LV mass, meanwhile ∆↓TSH and ∆↓triglyceride for ∆↓ANGPTL3, ∆↑free T3 and ∆↓HOMA-IR for ∆↓ANGPTL4, and systolic blood pressure and waist circumference for ∆↓ANGPTL8 among LT4-OH.

CONCLUSION

Elevated ANGPTL3, 4 and 8 levels are differentially independent predictors of endothelial and cardiac function and are reduced with LT4 in SCH and OH.

Transcriptomic therapy for dyslipidemias utilizing nucleic acids targeted at ANGPTL3

Angiopoietin-like protein 3 (ANGPTL3) is a key physiological regulator of plasma lipid and lipoprotein metabolism that involves the control of enzymes, lipoprotein and endothelial lipases. Inhibition of ANGPTL3 offers a new approach for correcting the health risks of dyslipidemia, including familial hypercholesterolemia, mixed hyperlipidemia, metabolic syndrome and/or severe hypertriglyceridemia. ANGPTL3 inhibition with nucleic acid-based antisense oligonucleotide and siRNA can correct dyslipidemia chiefly by reducing production and increasing catabolism of triglyceride-rich lipoprotein and LDL particles. Early clinical trials have demonstrated that these agents can safely and effectively lower plasma triglyceride and LDL-cholesterol levels by up to 70 and 50%, respectively. However, the long-term safety and cost-effectiveness of these agents await to be confirmed in an ongoing and future clinical trials.

Serum Angiopoietin-like Protein 3 Level Is Associated with Peripheral Arterial Stiffness in Patients with Coronary Artery Disease

Background and Objectives: Angiopoietin-like protein 3 (ANGPTL3) is a secretory protein regulating lipid metabolism. This study evaluated the relationship between serum ANGPTL3 level and peripheral arterial stiffness (PAS) in patients with coronary artery disease (CAD). Materials and Methods: Fasting blood samples were collected from 95 CAD patients. PAS was defined as left or right brachial-ankle pulse wave velocity (baPWV) > 18.0 m/s by an oscillometric method. Serum ANGPTL3 levels were assessed using a commercial enzyme-linked immunosorbent assay kit. Results: Seventeen CAD patients (17.9%) had PAS. Patients with PAS had a significantly higher percentage of diabetes (p = 0.002), older age (p = 0.030), higher systolic blood pressure (p = 0.016), higher fasting glucose (p = 0.008), serum C-reactive protein (p = 0.002), and ANGPTL3 level (p = 0.001) than those without PAS. After multivariable logistic regression analysis, serum ANGPTL3 level (Odds ratio (OR): 1.004, 95% confidence interval (CI): 1.000–1.007, p = 0.041) is still independently associated with PAS in CAD patients. The receiver operating characteristic curve for PAS prediction revealed that the area under the curve for ANGPTL3 level was 0.757 (95% CI: 0.645–0.870, p < 0.001). Conclusions: Serum fasting ANGPTL3 level is positively associated with PAS in CAD patients. Further studies are required for clarification.

ANGPTL3 Overexpression Suppresses the Development of Oncogenic Properties in Renal Cell Carcinoma via the Wnt/β-Catenin Signaling Pathway and Predicts Good Prognosis

Angiopoietin-like 3 (ANGPTL3), which is involved in new blood vessel growth, has been reported to exhibit an abnroaml expression in many different cancers. However, the expressing pattern and functions of ANGPTL3 renal cell carcinoma (RCC) were rarely reported. In this study, we observed that ANGPTL3 expression was distinctly downregulated in both RCC specimens from TCGA datasets and cell lines. Survival assays also revealed that patients with low ANGPTL3 expression exhibited a shorter overall survival and disease-free survival than those with high ANGPTL3 expression. Cell counting kit-8 (CCK-8) assay, Colony formation assay, and flow cytometry showed that overexpression of ANGPTL3 distinctly suppressed the proliferation of RCC cells, and promoted apoptosis. Transwell assays and Wound healing assays revealed that ANGPTL3 upregulation suppressed the migration and invasion of RCC cells. Then, we explored whether ANGPTL3 dysregulation influenced the alteration of Wnt/β-catenin signaling using TOP/FOP flash reporter assays and western blot. The results showed that overexpression of ANGPTL3 distinctly suppressed the activity of Wnt/β-catenin signaling. Overall, our results confirmed that overexpression of ANGPTL3 was related to the malignancy and good prognosis of RCC patients, and ANGPTL3 upregulation inhibited the tumor proliferation and metastasis via the Wnt/β-catenin pathway. ANGPTL3 may be a novel therapeutic target and a prognostic biomarker for RCC patients.

Targeting angiopoietin-like 3 in atherosclerosis: From bench to bedside

Atherosclerotic cardiovascular disease (ASCVD) is the largest cause of morbidity and mortality worldwide. Lipid-lowering therapies are the current major cornerstone of ASCVD management. Statins, ezetimibe, fibrates and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors effectively reduce the plasma low-density lipoprotein cholesterol (LDL-C) level in most individuals at risk of atherosclerosis. Still, some patients (such as those with homozygous familial hypercholesterolaemia), who do not respond to standard therapies, and other patients who cannot take these agents, remain at a high risk of ASCVD. In recent years there has been tremendous progress in understanding the mechanism and efficacy of lipid-lowering strategies. Apart from the recently approved PCSK9 and ATP citrate lyase inhibitors, angiopoietin-like 3 (ANGPTL3) is another potential target for the treatment of dyslipidaemia and its clinical sequalae of atherosclerosis. ANGPTL3 is a pivotal modulator of plasma triglycerides (TG), LDL-C and high-density lipoprotein cholesterol (HDL-C) levels, achieved by inhibiting the activities of lipoprotein lipase and endothelial lipase. Familial combined hypolipidaemia is derived from the Angptl3 loss-of-function mutations, which leads to low levels of LDL-C, HDL-C and TG, and has a 34% decreased risk of ASCVD compared with non-carriers. To date, monoclonal antibodies (evinacumab) and antisense oligonucleotides against ANGPTL3 have been investigated in clinical trials for dyslipidaemia therapy. Herein, we review the biology and function of ANGPTL3, as well as the latest developments of ANGPTL3-targeted therapies. We also summarize evidence from basic research to clinical trials, with the aim of providing novel insights into the biological functions of ANGPTL3 and related targeted therapies.

Angiopoietin-Like Proteins 2 and 3 in Children and Adolescents with Obesity and Their Relationship with Hypertension and Metabolic Syndrome

Background

Angiopoietin-like protein 2 (ANGPTL2) is one of the adipocyte-derived inflammatory factors which connects obesity to insulin resistance. ANGPTL3 has a direct role in regulation of lipid metabolism. The objective of this study was to evaluate ANGPTL2 and ANGPTL3 in childhood obesity and their relationship with metabolic syndrome.

Methods

70 children and adolescents, 35 obese and 35 normal-weight subjects, were enrolled in this research after complete clinical examination and anthropometric evaluations. Serum ANGPTL2 and ANGPTL3 and insulin were measured by enzyme-linked immunosorbent assay (ELISA). Homeostatic model assessment of insulin resistance (HOMA-IR) was calculated and used to estimate insulin resistance (IR). Colorimetric methods were used for the assessment of fasting plasma glucose (FPG), LDL-C, HDL-C, total cholesterol (TC), and triglyceride (TG).

Results

The levels of ANGPTL2 and ANGPTL3 were significantly higher in obese subjects than those in controls, but they did not differ significantly in subjects with or without IR. ANGPTL3 was found to be significantly elevated in obese children with metabolic syndrome (MetS) in comparison with those without MetS. Both of the studied ANGPTLs were positively correlated with BMI, systolic blood pressure (SBP), diastolic blood pressure (DBP), TC, and LDL-C. The correlation between ANGPTL3 and either TC or LDL-C remained significant after adjusting for BMI.

Conclusion

Serum ANGPTL2 and ANGPTL3 were elevated in obesity and associated with blood pressure and indices of metabolic syndrome, suggesting that they might be involved in the advancement of obesity-related hypertension and metabolic syndrome.

Statin intolerance: new data and further options for treatment

PURPOSE OF REVIEW

Hypercholesterolemia is a major risk factor for cardiovascular diseases. Administration of statins represents the cornerstone of the prevention and treatment of cardiovascular disease, with demonstrated long-term safety and efficacy. This review aims to revisit statin intolerance mechanisms, as well as to discuss new data and therapeutic options.

RECENT FINDINGS

Although statins are well tolerated, myopathy and other adverse effects are a challenging problem, being the main reason for poor adherence to treatment and failure in lowering cardiovascular risk. Statin intolerance is the subject of ongoing research, as these drugs are widely used. There are alternative options of treatment if statin intolerance emerges, that is, lowering the dose, intermittent dosages, and/or combining a statin with other drugs, such as ezetimibe, proprotein convertase subtilisin-kexin type 9 inhibitors, bempedoic acid, angiopoietin-like 3 protein inhibitors, and nutraceuticals. If even the lowest statin dose cannot be tolerated, a nonstatin regimen is recommended to reduce LDL cholesterol levels.

SUMMARY

Treatment options in statin intolerance include combinations of a lower dose of statin with other lipid-lowering regimens or only nonstatin drugs in the presence of complete intolerance. New hypolipidemic therapies that address gene editing are emerging, and may prove useful in the future.

Lipoproteins in chronic kidney disease: from bench to bedside

Chronic kidney disease (CKD) is associated with high cardiovascular risk. CKD patients exhibit a specific lipoprotein pattern termed 'uraemic dyslipidaemia', which is characterized by rather normal low-density lipoprotein cholesterol, low high-density lipoprotein cholesterol, and high triglyceride plasma levels. All three lipoprotein classes are involved in the pathogenesis of CKD-associated cardiovascular diseases (CVDs). Uraemia leads to several modifications of the structure of lipoproteins such as changes of the proteome and the lipidome, post-translational protein modifications (e.g. carbamylation) and accumulation of small-molecular substances within the lipoprotein moieties, which affect their functionality. Lipoproteins from CKD patients interfere with lipid transport and promote inflammation, oxidative stress, endothelial dysfunction as well as other features of atherogenesis, thus contributing to the development of CKD-associated CVD. While, lipid-modifying therapies play an important role in the management of CKD patients, their efficacy is modulated by kidney function. Novel therapeutic agents to prevent the adverse remodelling of lipoproteins in CKD and to improve their functional properties are highly desirable and partially under development.

ANGPTL3 and Apolipoprotein C-III as Novel Lipid-Lowering Targets

PURPOSE OF REVIEW

Despite significant progress in plasma lipid lowering strategies, recent clinical trials highlight the existence of residual cardiovascular risk. Angiopoietin-like protein 3 (ANGPTL3) and apolipoprotein C-III (Apo C-III) have been identified as novel lipid-lowering targets.

RECENT FINDINGS

Apo C-III and ANGPTL3 have emerged as novel regulators of triglyceride (TG) and low-density lipoprotein-cholesterol (LDL-C) levels. ANGPTL3 is an inhibitor of lipoprotein lipase (LPL), reducing lipolysis of Apo B-containing lipoproteins. Loss-of-function ANGPLT3 mutations are associated with reduced plasma cholesterol and TG, while novel ANGPLT3 inhibition strategies, including monoclonal antibodies (evinacumab), ANGPLT3 antisense oligonucleotides (IONIS-ANGPTL3-L_Rx), and small interfering RNA (siRNA) silencing techniques (ARO-ANG3), result in increased lipolysis and significant reductions of LDL-C and TG levels in phase I and II clinical trials. Similarly, Apo C-III inhibits LPL while promoting the hepatic secretion of TG-rich lipoproteins and preventing their clearance. Loss-of-function APOC3 mutations have been associated with reduced TG levels. Targeting of Apo C-III with volanesorsen, an APOC3 siRNA, results in significant reduction in plasma TG levels but possibly also increased risk for thrombocytopenia, as recently demonstrated in phase I, II, and III clinical trials. ARO-APOC3 is a novel siRNA-based agent targeting Apo C-III which is currently under investigation with regard to its lipid-lowering efficiency. ANGPTL3 and Apo C-III targeting agents have demonstrated striking lipid-lowering effects in recent clinical trials; however, more thorough safety and efficacy data are required. Here, we evaluate the role of ANGPLT3 and Apo C-III in lipid metabolism, present the latest clinical advances targeting those molecules, and outline the remaining scientific challenges on residual lipid-associated cardiovascular risk.

Evaluation of angiopoietin-like protein 3 (ANGPTL3) levels in polycystic ovary syndrome

AIM

Angiopoietin-like protein 3 (ANGPTL3) is recognized as a regulator of lipid metabolism. However, little is known about its association with insulin resistance in polycystic ovary syndrome (PCOS) setting. The present study aimed to investigate the serum levels of ANGPTL3 and adiponectin in PCOS women compared to healthy controls.

MAIN METHOD

In this study, a total of 175 premenopausal women (117 PCOS and 58 non-PCOS) were enrolled. Serum concentrations of ANGPTL3, adiponectin, fasting insulin, and other hormonal variables were measured using ELISA technique.

KEY FINDINGS

Results showed that adiponectin levels were significantly lower in PCOS group than those of non-PCOS group. However, serum levels of ANGPTL3, high-sensitivity C-reactive protein (hs-CRP), and homocysteine (Hcy) were found to be higher in PCOS patients, when compared to non-PCOS ones. Moreover, serum ANGPTL3 positively correlated with BMI and serum triglyceride, while it inversely correlated with serum HDL-C in PCOS patients.

SIGNIFICANCE

Our results demonstrated that increased levels of ANGPTL3 correlated with insulin resistance and dyslipidemia in PCOS patients, highlighting the need for future studies targeting its role in the pathogenesis of this disease.

Familial combined hypolipidemia: angiopoietin-like protein-3 deficiency

PURPOSE OF REVIEW

Angiopoietin-like protein-3 (ANGPTL3) is emerging as a key player in lipoprotein transport with an expanding role on fatty acid and glucose metabolism. Its deficiency is associated with a favorable metabolic profile. The present review will highlight the recent understanding of metabolic and cardiovascular consequences of ANGPTL3 inactivation by considering both genetic and pharmacological investigations.

RECENT FINDINGS

Experimental studies have further illustrated the complex interplay between ANGPTL3 and ANGPTL4-8 in orchestrating lipid transport in different nutritional status. Individuals with familial combined hypolipidemia due to homozygous loss-of-function mutations in ANGPTL3 gene showed improved metabolism of triglyceride-rich lipoproteins during fasting and postprandial state and increased fatty acid oxidation and insulin sensitivity. Moreover, mendelian randomizations studies demonstrated that partial ANGPTL3 deficiency associates with reduced risk of atherosclerotic cardiovascular events and, eventually, diabetes mellitus. Finally, inactivation of ANGPTL3, using either a specific mAb or antisense oligonucleotide, was reported to reduce plasma levels of atherogenic lipoprotein in humans and improve hepatic fat infiltration in animal models.

SUMMARY

Human and animal studies have further dissected the complex role of ANGPTL3 in the regulation of energy substrate metabolism. Moreover, genetic and pharmacological investigations have convincingly indicated that the inactivation of ANGPTL3 may be a very promising strategy to treat atherogenic metabolic disorders.

ANGPTL3 Mutations in Unrelated Chinese Han Patients with Familial Hypercholesterolemia

BACKGROUND AND OBJECTIVE

Familial hypercholesterolemia (FH) is a severe genetic hyperlipidemia characterized by increased levels of low-density lipoprotein cholesterol (LDL-C), leading to premature atherosclerosis. Angiopoietin-like protein (ANGPTL3) is a hepatocyte-specific protein that can be used to lower LDL in FH. However, it was unknown whether ANGPTL3 variants are present in FH patients. This study was performed to identify ANGPTL3 variants in unrelated Chinese Han patients with FH.

METHODS AND RESULTS

We screened 80 patients with FH (total cholesterol >7.8mmol/L, LDL-cholesterol >4.9mmol/L) and 77 controls using targeted next-generation sequencing (NGS) of six FH candidate genes (LDLR, ApoB100, PCSK9, ABCG5, ABCG8, and ANGPTL3). Candidate pathogenic variants identified by NGS were validated by Sanger sequencing. Mutant and wild-type plasmids containing the variant sequence were constructed and verified by Sanger sequencing. The gene expression profile was analyzed by an expression profile chip in transfected HepG2 cells using quantitative real-time (qRT)-PCR. We identified 41 variants in 28 FH patients, including two ANGPTL3 mutations: one exonic (c.A956G: p.K319R) and one in the untranslated region (c.*249G>A). Gene ontology analyses found that the cholesterol metabolic process and ANGPTL3 expression were significantly up-regulated in the ANGPTL3 K319R mutation group compared with the wild-type group. qRT-PCR findings were consistent with the expression profile analysis.

CONCLUSION

Rare ANGPTL3 variants were identified in Chinese patients with FH, including ANGPTL3: p.(Lys319Arg) which affected the expression of ANGPTL3 and the cholesterol metabolic process as determined by bioinformatics analysis.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registration (ChiCTR-ROC-17011027) http://www.chictr.org.cn/listbycreater.aspx.

Angiopoietin-like proteins as therapeutic targets for cardiovascular disease: focus on lipid disorders

Introduction: Angiopoietin-like (ANGPTL) proteins belong to a family of eight secreted factors that are structurally related to proteins that modulate angiogenesi, commonly known as angiopoietins. Specifically, ANGPTL3, ANGPTL4, and ANGPTL8 (the 'ANGPT L3-4-8 triad'), have surfaced as principal regulators of plasma lipid metabolism by functioning as potent inhibitors of lipoprotein lipase. The targeting of these proteins may open up future therapeutic avenues for metabolic and cardiovascular disease.Areas covered: This article systematically summarizes the compelling literature describing the mechanistic roles of ANGPTL3, 4, and 8 in lipid metabolism, emphasizing their importance in determining the risk of cardiovascular disease. We shed light on population-based studies linking loss-of-function variations in ANGPTL3, 4, and 8 with decreased risk of metabolic conditions and cardiovascular disorders. We also discuss how the strategies aiming at targeting the ANGPT L3-4-8 triad could offer therapeutic benefit in the clinical scenario.Expert opinion: Monoclonal antibodies and antisense oligonucleotides that target ANGPTL3, 4, and 8 are potentially an efficient therapeutic strategy for hypertriglyceridemia and cardiovascular risk reduction, especially in patients with limited treatment options. These innovative therapeutical approaches are at an embryonic stage in development and hence further investigations are necessary for eventual use in humans.

Pharmacological aspects of ANGPTL3 and ANGPTL4 inhibitors: New therapeutic approaches for the treatment of atherogenic dyslipidemia

Among the determinants of atherosclerotic cardiovascular disease (ASCVD), genetic and experimental evidence has provided data on a major role of angiopoietin-like proteins 3 and 4 (ANGPTL3 and ANGPTL4) in regulating the activity of lipoprotein lipase (LPL), antagonizing the hydrolysis of triglycerides (TG). Indeed, beyond low-density lipoprotein cholesterol (LDL-C), ASCVD risk is also dependent on a cluster of metabolic abnormalities characterized by elevated fasting and post-prandial levels of TG-rich lipoproteins and their remnants. In a head-to-head comparison between murine models for ANGPTL3 and ANGPTL4, the former was found to be a better pharmacological target for the treatment of hypertriglyceridemia. In humans, loss-of-function mutations of ANGPTL3 are associated with a marked reduction of plasma levels of VLDL, low-density lipoprotein (LDL) and high-density lipoprotein (HDL). Carriers of loss-of-function mutations of ANGPTL4 show instead lower TG-rich lipoproteins and a modest but significant increase of HDL. The relevance of ANGPTL3 and ANGPTL4 as new therapeutic targets is proven by the development of monoclonal antibodies or antisense oligonucleotides. Studies in animal models, including non-human primates, have demonstrated that short-term treatment with monoclonal antibodies against ANGPTL3 and ANGPTL4 induces activation of LPL and a marked reduction of plasma TG-rich-lipoproteins, apparently without any major side effects. Inhibition of both targets also partially reduces LDL-C, independent of the LDL receptor. Similar evidence has been observed with the antisense oligonucleotide ANGPTL3-L_RX. The genetic studies have paved the way for the development of new ANGPTL3 and 4 antagonists for the treatment of atherogenic dyslipidemias. Conclusive data of phase 2 and 3 clinical trials are still needed in order to define their safety and efficacy profile.

The Forgotten Lipids: Triglycerides, Remnant Cholesterol, and Atherosclerotic Cardiovascular Disease Risk

Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of death worldwide. Low-density lipoprotein cholesterol (LDL-C) is a well-established mediator of atherosclerosis and a key target for intervention for the primary and secondary prevention of ASCVD. However, despite substantial reduction in LDL-C, patients continue to have recurrent ASCVD events. Hypertriglyceridemia may be an important contributor of this residual risk. Observational and genetic epidemiological data strongly support a causal role of triglycerides (TGs) and the cholesterol content within triglyceride-rich lipoproteins (TGRLs) and/or remnant cholesterol (RC) in the development of ASCVD. TGRLs are composed of hepatically derived very low-density lipoprotein and intestinally derived chylomicrons. RC is the cholesterol content of all TGRLs and plasma TGs serve as a surrogate measure of TGRLs and RC. Although lifestyle modification remains the cornerstone for management of hypertriglyceridemia, many novel drugs are in development and have shown impressive efficacy in lowering TG levels. Several ongoing, randomized controlled trials are underway to examine the impact of these novel agents on ASCVD outcomes. In this comprehensive review, we provide an overview of the biology, epidemiology, and genetics of TGs and ASCVD; we discuss current and novel TG-lowering therapies under development.

ANGPTL3: a novel biomarker and promising therapeutic target

Angiopoietin-like protein 3 (ANGPTL3) belongs to a multifunctional secreted protein that mainly expresses in the liver, and is regulated by numerous post-translational modifications, including multiple cleavage and glycosylation. Accumulating evidences have revealed that ANGPTL3 plays a critical role in both biological processes, such as lipid metabolism, angiogenesis and haematopoietic function and pathological changes, including atherosclerosis, carcinogenesis, nephrotic syndrome, diabetes, liver diseases and so on. Thus, ANGPTL3 may serve as a potential biomarker in these diseases. Furthermore, ANGPTL3 signalling pathways including LXR/ANGPTL3, thyroid hormone/ANGPTL3, insulin/ANGPTL3 and leptin/ANGPTL3 are also involved in physiological and pathological processes. Some biological ANGPTL3 inhibitors, chemical drugs and traditional Chinese medicine exert beneficial effects by targeting ANGPTL3 directly or indirectly. Therefore, elucidating the effects and underlying mechanisms of ANGPTL3 is essential to develop promising strategies in the diagnosis and treatment of related diseases.

ANGPTL3 Inhibitors - Their Role in Cardiovascular Disease Through Regulation of Lipid Metabolism

Elevated plasma lipid levels are linked to atherosclerosis, a hallmark for coronary artery disease (CAD), documented by animal studies as well as angiographic and clinical studies. The ability to treat hyperlipidemia through lifestyle changes and lipid-lowering agents has been related to the slow progression of atherosclerosis and decreased incidence of major coronary events. Angiopoietin-like proteins (ANGPTLs) are a family of secreted glycoproteins expressed in the liver that share common domain characteristics with angiopoietins, the main regulators of angiogenesis. Although ANGPTLs cannot bind the angiopoietin receptors expressed on endothelial cells, 2 ANGPTL family members (ANGPTL3 and ANGPTL4) have clinical importance because of their unambiguous effects on lipoprotein metabolism in mice and humans. The regulation of plasma lipid levels by ANGPTL3 is controlled via affecting lipoprotein lipase and endothelial lipase-mediated hydrolysis of triglycerides (TGs) and phospholipids. ANGPTL 3, along with the other 2 members, 4 and 8, is a key to balancing the distribution of circulating TGs between white adipose tissue (WAT) and oxidative tissues. Thus, ongoing trials with newly discovered medications in the form of monoclonal antibodies or antisense oligonucleotides with novel targets are under analysis and may represent a fresh frontier in the treatment of hyperlipidemia and CAD.