Fasting apolipoprotein B48 is associated with asymptomatic peripheral arterial disease in type 2 diabetic subjects: a case-control study

Dipeptidyl peptidase-4 inhibitor anagliptin reduces fasting apolipoprotein B-48 levels in patients with type 2 diabetes: A randomized controlled trial

Type 2 diabetes and dyslipidemia are diseases that collectively increase the risk of patients developing cardiovascular complications. Several incretin-based drugs are reported to improve lipid metabolism, and one of these medications, anagliptin, is a dipeptidyl peptidase-4 (DPP-4) inhibitor that has been shown to decrease serum triglyceride and low-density lipoproteins cholesterol. This study aimed to conduct an investigation into the effects of anagliptin on serum lipid profiles. This multicenter, open-label, randomized (1:1), parallel group study was designed to evaluate the effects of anagliptin on serum lipid profiles (triglycerides, lipoproteins, apolipoproteins, and cholesterol fractions). The study involved 24 patients with type 2 diabetes at two participating hospitals for a period of 24 weeks. Patients were randomly assigned to the anagliptin (n = 12) or control (n = 12) groups. Patients in the anagliptin group were treated with 200 mg of the drug twice daily. Patients in the control group did not receive anagliptin, but continued with their previous treatment schedules. Lipid metabolism was examined under fasting conditions at baseline and 24 weeks. Patients treated with anagliptin for 24 weeks exhibited significantly reduced levels of serum apolipoprotein B-48, a marker for lipid transport from the intestine, compared with the control group patients (P < 0.05). After 24 weeks of treatment, serum adiponectin levels were significantly raised, whereas glycated hemoglobin (HbA1c) levels were significantly lower compared with the baseline in the anagliptin group (P < 0.05), but not in the control group. This study showed that the DPP-4 inhibitor anagliptin reduces fasting apolipoprotein B-48 levels, suggesting that this drug may have beneficial effects on lipid metabolism possibly mediated by the inhibition of intestinal lipid transport.

Fasting apolipoprotein B48 is associated with large artery atherosclerotic stroke: a case-control study

Fasting Apolipoprotein B48 (ApoB48) is reported to be a well surrogate marker for postprandial lipidemia and have been repeatedly associated with cardiovascular disease. However, whether ApoB48 is also a risk factor for ischemic stroke have not been reported. In this study, our object is to explore the relationship between fasting plasma ApoB48 levels and the large artery atherosclerotic (LAA) stroke.A 1:1 age-(±2), gender-matched case-control study was conducted. LAA patients and healthy controls admitted to our center were prospectively recruited. Clinical data were collected and enzyme-linked immunosorbent assay (ELISA) was used to measure the fasting plasma ApoB48 levels.A cohort of 234 LAA stroke patients and 234 controls were enrolled. Fasting plasma ApoB48 levels were significantly higher in LAA stroke patients than in controls (4.76(3.46) vs 4.00(2.4), P < 0.001). Conditional multivariable analyses indicated that fasting ApoB48 levels were associated with LAA stroke (odds ratio: 1.18; 95% confidence interval: 1.04–1.35; P = 0.014).Our study indicates that increased fasting plasma ApoB48 may be a risk factor for LAA stroke.

Polymorphisms rs2167444 and rs508384 in the SCD1 Gene Are Linked with High ApoB-48 Levels and Adverse Profile of Cardiometabolic Risk Factors

Elevated plasma concentration of apolipoprotein B-48 (apoB-48) is an independent risk factor of cardiovascular disease. Stearoyl-CoA desaturase-1 (SCD1) is a rate-limiting lipogenic enzyme and a key regulator of fuel metabolism. The aim of this study was to analyse associations between clinical, biochemical, and genetic factors and different apoB-48 levels in subjects at increased cardiometabolic risk. We examined 220 subjects exhibiting at least one metabolic syndrome (MetS) component. In conjunction with basic clinical, anthropometric and laboratory measurements, we analysed various polymorphisms of stearoyl-CoA desaturase-1 (SCD1). Subjects were divided into two groups according to the median apoB-48 level: (1) high apoB-48 (≥ 7.9 mg/l, N = 112) and (2) low apoB-48 (< 7.9 mg/l, N = 108). Neither group differed significantly in anthropometric measures. High plasma apoB-48 levels were associated with increased systolic blood pressure (+3 %; P < 0.05), MetS prevalence (59.8 vs. 32.4 %; P < 0.001), small-dense LDL frequency (46.4 vs. 20.4 %; P < 0.001), triglycerides (+97 %; P < 0.001), non-HDLcholesterol (+27 %; P < 0.001), and lower concentrations of HDL-cholesterol (-11 %; P < 0.01). This group was further characterized by a higher HOMA-IR index (+54 %; P < 0.001) and increased concentrations of conjugated dienes (+11 %; P < 0.001) and oxidatively modified LDL (+ 38 %; P < 0.05). Lower frequencies of SCD1 minor genotypes (rs2167444, rs508384, P < 0.05) were observed in subjects with elevated plasma concentrations of apoB-48. Elevated plasma concentrations of apoB-48 are associated with an adverse lipid profile, higher systolic blood pressure, insulin resistance, and oxidative stress. Lower proportions of minor SCD1 genotypes (rs2167444, rs508384) implicate the role of genetic factors in the pathogenesis of elevated levels of apoB-48.

Chylomicrons: Advances in biology, pathology, laboratory testing, and therapeutics

The adequate absorption of lipids is essential for all mammalian species due to their inability to synthesize some essential fatty acids and fat-soluble vitamins. Chylomicrons (CMs) are large, triglyceride-rich lipoproteins that are produced in intestinal enterocytes in response to fat ingestion, which function to transport the ingested lipids to different tissues. In addition to the contribution of CMs to postprandial lipemia, their remnants, the degradation products following lipolysis by lipoprotein lipase, are linked to cardiovascular disease. In this review, we will focus on the structure-function and metabolism of CMs. Second, we will analyze the impact of gene defects reported to affect CM metabolism and, also, the role of CMs in other pathologies, such as atherothrombotic cardiovascular disease and diabetes mellitus. Third, we will provide an overview of the laboratory tests currently used to study CM disorders, and, finally, we will highlight current treatments in diseases affecting CMs.

Lipoprotein effects of incretin analogs and dipeptidyl peptidase 4 inhibitors

Elevated post-prandial lipoprotein levels are common in patients with type 2 diabetes. Post-prandial lipoprotein alterations in type 2 diabetics are widely believed to drive inflammation and are considered a major risk factor for cardiovascular disease in diabetic patients. The incretins glucagon like peptide-1 (GLP-1) and glucose insulinotropic peptide (GIP) modulate post-prandial lipoproteins through a multitude of pathways that are independent of insulin and weight loss. Evidence from both animal models and humans seems to suggest an important effect on triglyceride rich lipoproteins (Apo48 containing) with little to no effects on other lipoproteins at least in humans. Dipeptidyl peptidase-4 (DPP4) inhibitors also appear to share these effects suggesting an important role for incretins in these effects. In this review, we will summarize lipid modulating effects of incretin analogs and DPP-4 inhibitors in both animal models and human studies and provide an overview of mechanisms responsible for these effects.

Insights from human congenital disorders of intestinal lipid metabolism

The intestine must challenge the profuse daily flux of dietary fat that serves as a vital source of energy and as an essential component of cell membranes. The fat absorption process takes place in a series of orderly and interrelated steps, including the uptake and translocation of lipolytic products from the brush border membrane to the endoplasmic reticulum, lipid esterification, Apo synthesis, and ultimately the packaging of lipid and Apo components into chylomicrons (CMs). Deciphering inherited disorders of intracellular CM elaboration afforded new insight into the key functions of crucial intracellular proteins, such as Apo B, microsomal TG transfer protein, and Sar1b GTPase, the defects of which lead to hypobetalipoproteinemia, abetalipoproteinemia, and CM retention disease, respectively. These "experiments of nature" are characterized by fat malabsorption, steatorrhea, failure to thrive, low plasma levels of TGs and cholesterol, and deficiency of liposoluble vitamins and essential FAs. After summarizing and discussing the functions and regulation of these proteins for reader's comprehension, the current review focuses on their specific roles in malabsorptions and dyslipidemia-related intestinal fat hyperabsorption while dissecting the spectrum of clinical manifestations and managements. The influence of newly discovered proteins (proprotein convertase subtilisin/kexin type 9 and angiopoietin-like 3 protein) on fat absorption has also been provided. Finally, it is stressed how the overexpression or polymorphism status of the critical intracellular proteins promotes dyslipidemia and cardiometabolic disorders.

Peripheral arterial disease, type 2 diabetes and postprandial lipidaemia: Is there a link?

Peripheral arterial disease, manifested as intermittent claudication or critical ischaemia, or identified by an ankle/brachial index < 0.9, is present in at least one in every four patients with type 2 diabetes mellitus. Several reasons exist for peripheral arterial disease in diabetes. In addition to hyperglycaemia, smoking and hypertension, the dyslipidaemia that accompanies type 2 diabetes and is characterised by increased triglyceride levels and reduced high-density lipoprotein cholesterol concentrations also seems to contribute to this association. Recent years have witnessed an increased interest in postprandial lipidaemia, as a result of various prospective studies showing that non-fasting triglycerides predict the onset of arteriosclerotic cardiovascular disease better than fasting measurements do. Additionally, the use of certain specific postprandial particle markers, such as apolipoprotein B-48, makes it easier and more simple to approach the postprandial phenomenon. Despite this, only a few studies have evaluated the role of postprandial triglycerides in the development of peripheral arterial disease and type 2 diabetes. The purpose of this review is to examine the epidemiology and risk factors of peripheral arterial disease in type 2 diabetes, focusing on the role of postprandial triglycerides and particles.

New and emerging regulators of intestinal lipoprotein secretion

Overproduction of hepatic apoB100-containing VLDL particles has been well documented in animal models and in humans with insulin resistance such as the metabolic syndrome and type 2 diabetes, and contributes to the typical dyslipidemia of these conditions. In addition, postprandial hyperlipidemia and elevated plasma concentrations of intestinal apoB48-containing chylomicron and chylomicron remnant particles have been demonstrated in insulin resistant states. Intestinal lipoprotein production is primarily determined by the amount of fat ingested and absorbed. Until approximately 10 years ago, however, relatively little attention was paid to the role of the intestine itself in regulating the production of triglyceride-rich lipoproteins (TRL) and its dysregulation in pathological states such as insulin resistance. We and others have shown that insulin resistant animal models and humans are characterized by overproduction of intestinal apoB48-containing lipoproteins. Whereas various factors are known to regulate hepatic lipoprotein particle production, less is known about factors that regulate the production of intestinal lipoprotein particles. Monosacharides, plasma free fatty acids (FFA), resveratrol, intestinal peptides (e.g. GLP-1 and GLP-2), and pancreatic hormones (e.g. insulin) have recently been shown to be important regulators of intestinal lipoprotein secretion. Available evidence in humans and animal models strongly supports the concept that the small intestine is not merely an absorptive organ but rather plays an active role in regulating the rate of production of chylomicrons in fed and fasting states. Metabolic signals in insulin resistance and type 2 diabetes and in some cases an aberrant intestinal response to these factors contribute to the enhanced formation and secretion of TRL. Understanding the regulation of intestinal lipoprotein production is imperative for the development of new therapeutic strategies for the prevention and treatment of dyslipidemia. Here we review recent developments in this field and present evidence that intestinal lipoprotein production is a process with metabolic plasticity and that modulation of intestinal lipoprotein secretion may be a feasible therapeutic strategy in the treatment of dyslipidemia and possibly prevention of atherosclerosis.