Elevated Plasma Cholesterol Levels Research Articles

480-P: Diabetes and Experimental Myocardial Infarction Synergize to Accelerate Atherosclerosis Destabilization

In addition to increasing the risk of an initial myocardial infarction (MI), diabetes increases the risk of a recurrent MI. Work by others suggests that an experimental MI can accelerate atherosclerosis via monocytosis. To test if diabetes and experimental myocardial infarction synergize to accelerate atherosclerosis, we induced atherosclerosis in Ldlr-/-; Gp+ mice, lethally irradiated them and transplanted with either wild type (WT) or LysM-Cre-mediated CD49D-deficient bone marrow. Following recovery, diabetes was induced using lymphocytic choriomeningitis virus, or saline was used as a control. The mice were subjected to ligation of the left anterior descending coronary artery to induce experimental MI or a sham surgery and then maintained for an additional 3 weeks. Diabetic (D) mice exhibited hyperglycemia and elevated plasma cholesterol and triglyceride levels compared to nondiabetic (ND) mice, but neither hematopoietic genotype or MI influenced that. All mice subjected to MI had significantly reduced left ventricular function. Neither diabetes nor MI resulted in monocytosis compared to ND sham mice. Despite not affecting total lesion size, the combination of diabetes and MI resulted in larger necrotic cores in the aortic sinus and in the brachiocephalic artery (9.8 ± 1% of total lesion in aortic sinus in ND sham, 11.9 ± 1% in ND MI, 15.4 ± 1% in D sham and 18.1 ± 2% in D MI, P<0.001 comparing ND Sham to D MI, n=14-24, ANOVA). The expansion of the necrotic cores was dependent on monocyte recruitment, since mice with myeloid cells deficient in the adhesion molecule CD49D were protected from necrotic core expansion. Diabetes and MI also synergized to accelerate macrophage cell death (6.1 ± 3% of peritoneal macrophages were dead in ND sham, 6.1 ± 3% in ND MI, 11± 1% in D sham and 20 ± 3% in D MI, n=3-6, p<0.05 ANOVA). In summary, diabetes and experimental MI destabilize the atherosclerotic lesion, potentially explaining why patients with diabetes are at an increased risk of recurrent MI. Disclosure F. Kramer: None. A.M. Martinson: None. T. Papayannopoulou: None. C.E. Murry: Other Relationship; Self; Cytocardia. J.E. Kanter: None. Funding American Diabetes Association (1-16-IBS-153 to J.E.K.)

Pengaruh Latihan Fisik Terhadap Risiko Kardiometabolik (Trigliserida) pada Wanita Usia Reproduktif

Cardiometabolic or metabolic syndromes are a group of risk factors that are directly related to the occurrence of heart disease, including diabetes and elevated levels of plasma glucose, obesity, cholesterol, triglycerides, and high blood pressure. The research aimed to investigate the effect of the physical exercise on the cardiometabolic risk factor (triglyceride) of reproductive-aged women in the coastal area. The research used the quasi-experimental method with one-group pre-test and post-test design. Samples were taken using the purposive sampling technique. The blood was taken on 117 reproductive age women (61 coastal area samples and 56 non-coastal area samples) before and after the physical exercise to check the blood triglyceride level using the spectrophotometer. The comparison of the triglyceride level between the samples dwelling in the coastal area and the noncoastal area was only carried out before the physical exercise. The type of physical exercise was the aerobics gymnastic which was conducted 3 times a week for 8 weeks with a duration of 60 minutes. The research results indicate that there is no significant difference in the triglyceride level based on the respondents domicile with the value of p = 0.154 that mean is the significant correlation between the triglyceride level category before and after the physical exercise (the normal category from 94 subjects to become 114 subjects, high limit category from 16 subjects to become 3 subjects, high category from 6 subjects to become none, and very high category from 1 subject to become none with the value of p = 0.001). There is a significant decrease on the triglyceride level after the physical exercise (122.83 mg/dL ± 75.99 to become 106.19 mg/dL ± 29.86, p=0.003). Therefore, physical exercise can decrease the triglyceride level, whereas the coastal and noncoastal domiciles do not have an effect on the triglyceride level.

Prevalence of dyslipidemia associated with complications in diabetic patients: a nationwide study in Thailand

BackgroundDyslipidemia is an important modifiable risk factor for cardiovascular disease. It is diagnosed by the presence of an abnormal lipid profile, primarily with elevated levels of plasma cholesterol, triglyceride, or both, or reduced levels of high-density lipoprotein cholesterol. However, some studies have reported increased risk of ischemic stroke with elevated low-density lipoprotein cholesterol (LDL-C) levels and increased risk of cardiovascular mortality independent of LDL-C levels in type 2 diabetes mellitus (T2DM) patients.MethodsIn this cross-sectional study, data were included for Thai adults with diabetes from the Diabetes Mellitus/ Hypertension (DM/HT) study, 2010–2014 (data was collected by the Medical Research Network of the Consortium of Thai Medical Schools). The target population comprised T2DM patients who were treated at a hospital for more than 12 months. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated to determine factors associated with dyslipidemia.ResultsIn total, 140,557 participants (average age, 60 years) were enrolled, with a dyslipidemia prevalence of 88.9% in the cohort. The factors associated with dyslipidemia included female sex (aOR: 1.47, 95% CI: 1.38–1.56); age < 50 years (aOR: 1.16, 95% CI: 1.10–1.22); waist circumference ≥ 90 cm in males and ≥ 80 cm in females (aOR: 1.23, 95% CI: 1.16–1.31); treatment at a primary care unit (aOR: 1.28, 95% CI: 1.23–1.33); and a history of unknown stroke (aOR: 1.10, 95% CI: 1.02–1.19), coronary revascularization (aOR: 0.85, 95% CI: 0.79–0.91), diabetic nephropathy (aOR: 1.06, 95% CI: 1.01–1.12), or renal insufficiency (aOR: 1.08, 95% CI: 1.02–1.13).ConclusionsDyslipidemia is prevalent among Thai T2DMpatients and is associated with gender; age; obesity; central obesity; treatment at a primary care unit; and a history of unknown stroke, coronary revascularization, diabetic nephropathy, and renal insufficiency. Our study results will help increase the awareness of healthcare providers regarding dyslipidemia in diabetic patients. To reduce cardiovascular risk, healthcare professionals should provide regular follow-up and proper advice and ensure primary prevention of vascular complications. Improved education and increased self-awareness regarding the need to change behaviors and regular intake of medication would help decrease dyslipidemia prevalence among diabetic patients.

The atheroprotective effects of genistein in hypercholestrolemic male rabbit

Objective The occurrence of this disease is related to different risk factors such as cardiovascular issues and elevated levels of plasmacholesterol, hypertension, diabetes mellitus and many others.Methods Three groups of domestic male rabbits, six in each group, were studied. Each group constituted a different diet condition wheregroup I had a normal chow diet; group II a 1% cholesterol-diet, group III a 1% cholesterol-diet and Genistein. The level of serum totalcholesterol (TC), triglycerides (TG) and HDL-C serum interleukin-6 (IL-6), serum high sensitive C-reactive protein (hs-CRP), serum monocytechemo-attractant protein type 1 (MCP-1) and HMG-box1 was monitored by collecting blood samples at the start of the study, 28 and 56 days.Then, the aorta was removed to be examined (histopathology) for atherosclerosis lesion and thickening in the aortic intima-media.Results In comparison to the control group (I), levels of TC, TG, low-density lipoprotein (LDL) cholestrol, very LDL cholestrol, hs-CRP, IL-6,MCP-1 and HMG-box1 had increased while serum HDL-C had reduced in the animals that followed a high-fat diet. Histologically, the aorticintimal thickening and atherosclerosis lesions has increased in the induced-untreated animals. The Genistein treated group showed asubstantial decrease of lipid parameters in comparison with the induced-untreated group. Genistein counteracted the changes in hs-CRP,IL-6, MCP-1 and HMG-box1 in compared with the induced-untreated group (P &lt; 0.05). Histomorphometric measurements indicated thatGenistein significantly minimizes the thickness of the aortic intima-media and atherosclerosis lesions in comparison to the animals on ahigh-fat diet.Conclusion The outcomes of this investigation show that Genistein significantly decrease the progression of atherosclerosis inhypercholesterolemic animals via inhibition of inflammatory markers and reduced levels of lipid parameters.

Endogenous cholesterol ester hydroperoxides modulate cholesterol levels and inhibit cholesterol uptake in hepatocytes and macrophages

Dysregulation of cholesterol metabolism represents one of the major risk factors for atherosclerotic cardiovascular disease (CVD). Oxidized cholesterol esters (oxCE) in low-density lipoprotein (LDL) have been implicated in CVD but the underlying mechanisms remain poorly defined. We use a targeted lipidomic approach to demonstrate that levels of oxCEs in human plasma are associated with different types of CVD and significantly elevated in patients with myocardial infarction. We synthesized a major endogenous cholesterol ester hydroperoxide (CEOOH), cholesteryl-13(cis, trans)-hydroperoxy-octadecadienoate (ch-13(c,t)-HpODE) and show that this endogenous compound significantly increases plasma cholesterol level in mice while decrease cholesterol levels in mouse liver and peritoneal macrophages, which is primarily due to the inhibition of cholesterol uptake in macrophages and liver. Further studies indicate that inhibition of cholesterol uptake by ch-13(c,t)-HpODE in macrophages is dependent on LXRα-IDOL-LDLR pathway, whereas inhibition on cholesterol levels in hepatocytes is dependent on LXRα and LDLR. Consistently, these effects on cholesterol levels by ch-13(c,t)-HpODE are diminished in LDLR or LXRα knockout mice. Together, our study provides evidence that elevated plasma cholesterol levels by CEOOHs are primarily due to the inhibition of cholesterol uptake in the liver and macrophages, which may play an important role in the pathogenesis of CVD.

Genomic and Transcriptomic Analysis of Hypercholesterolemic Rabbits: Progress and Perspectives.

Rabbits (Oryctolagus cuniculus) are one of the most widely used animal models for the study of human lipid metabolism and atherosclerosis because they are more sensitive to a cholesterol diet than other experimental animals such as rodents. Currently, two hypercholesterolemic rabbit models are frequently used for atherosclerosis studies. One is a cholesterol-fed wild-type rabbit and the other is the Watanabe heritable hyperlipidemic (WHHL) rabbit, which is genetically deficient in low density lipoprotein (LDL) receptor function. Wild-type rabbits can be easily induced to develop severe hypercholesterolemia with a cholesterol-rich diet due to the marked increase in hepatically and intestinally derived remnant lipoproteins, called β-very low density lipoproteins (VLDL), which are rich in cholesteryl esters. WHHL rabbits are characterized by elevated plasma LDL levels on a standard chow diet, which resembles human familial hypercholesterolemia. Therefore, both rabbit models develop aortic and coronary atherosclerosis, but the elevated plasma cholesterol levels are caused by completely different mechanisms. In addition, cholesterol-fed rabbits but not WHHL rabbits exhibit different degrees of hepatosteatosis. Recently, we along with others have shown that there are many differentially expressed genes in the atherosclerotic lesions and livers of cholesterol-fed rabbits that are either significantly up- or down-regulated, compared with those in normal rabbits, including genes involved in the regulation of inflammation and lipid metabolism. Therefore, dietary cholesterol plays an important role not only in hypercholesterolemia and atherosclerosis but also in hepatosteatosis. In this review, we make an overview of the recent progress in genomic and transcriptomic analyses of hypercholesterolemic rabbits. These transcriptomic profiling data should provide novel insight into the relationship between hypercholesterolemia and atherosclerosis or hepatic dysfunction caused by dietary cholesterol.

Abstract 17401: Diesel Exhaust Induces Mitochondrial Dysfunction, Hyperlipidemia and Liver Steatosis

Introduction: Air pollution associates with increased cardiovascular morbidity and mortality, partly due to induction of dyslipidemia and metabolic syndrome. Our goal was to dissect mechanisms involved. Hypothesis: Diesel exhaust exposure induces hyperlipidemia and liver steatosis by dysregulating lipid metabolism, and altering gut microbiota composition. Methods: We assessed the effects of exposure to air pollution on lipid metabolism in mice through assessment of plasma lipids and lipoproteins, oxidized fatty acids 9-HODE and 13-HODE, lipid and carbohydrate metabolism, and gut microbiota composition. Findings were corroborated and mechanisms further assessed in culture of HepG2 hepatocytes. Results: ApoE KO mice exposed to inhaled diesel exhaust (DE, 6 hours/day, 5 days/week for 16 weeks) exhibited significantly (p&lt; 0.05) elevated plasma cholesterol and triglyceride levels, increased hepatic triglyceride content, and increased hepatic levels of 9-HODE and 13-HODE (oxidative products of linoleic acid) indicative of increased oxidative stress, as compared with control mice treated with filtered air (FA). DE also led to downregulation of Acad9 , which suggested decreased β-oxidation of fatty acids and decreased lipid catabolism. A direct effect of DEP exposure on hepatocytes was demonstrated by treatment of HepG2 cells with a methanol extract of DE particles followed by loading with oleic acid. As observed in vivo , this led to decreased ACAD9 expression, increased triglyceride content, and altered total, mitochondrial and ATP-linked respiration assessed by a Seahorse metabolic flux analyzer, indicative of mitochondrial dysfunction. Direct treatment of mitochondrias with DE particles affected mitochondrial complexes I and IV. Conclusions: Diesel exhaust exposure leads to dyslipidemia and liver steatosis in ApoE KO mice, likely due to mitochondrial dysfunction and decreased lipid catabolism.

Deletion of Lymphangiogenic and Angiogenic Growth Factor VEGF-D Leads to Severe Hyperlipidemia and Delayed Clearance of Chylomicron Remnants.

Objective- Dyslipidemia is one of the key factors behind coronary heart disease. Blood and lymphatic vessels play pivotal roles in both lipoprotein metabolism and development of atherosclerotic plaques. Recent studies have linked members of VEGF (vascular endothelial growth factor) family to lipid metabolism, but the function of VEGF-D has remained unexplored. Here, we investigated how the deletion of VEGF-D affects lipid and lipoprotein metabolism in atherogenic LDLR-/- ApoB100/100 mice. Approach and Results- Deletion of VEGF-D (VEGF-D-/-LDLR-/-ApoB100/100) led to markedly elevated plasma cholesterol and triglyceride levels without an increase in atherogenesis. Size distribution and hepatic lipid uptake studies confirmed a delayed clearance of large chylomicron remnant particles that cannot easily penetrate through the vascular endothelium. Mechanistically, the inhibition of VEGF-D signaling significantly decreased the hepatic expression of SDC1 (syndecan 1), which is one of the main receptors for chylomicron remnant uptake when LDLR is absent. Immunohistochemical staining confirmed reduced expression of SDC1 in the sinusoidal surface of hepatocytes in VEGF-D deficient mice. Furthermore, hepatic RNA-sequencing revealed that VEGF-D is also an important regulator of genes related to lipid metabolism and inflammation. The lack of VEGF-D signaling via VEGFR3 (VEGF receptor 3) led to lowered expression of genes regulating triglyceride and cholesterol production, as well as downregulation of peroxisomal β-oxidation pathway. Conclusions- These results demonstrate that VEGF-D, a powerful lymphangiogenic and angiogenic growth factor, is also a major regulator of chylomicron metabolism in mice.

Saturated Fat: Part of a Healthy Diet.

Despite the American public following recommendations to decrease absolute dietary fat intake and specifically decrease saturated fat intake, we have seen a dramatic rise over the past 40years in the rates of non-communicable diseases associated with obesity and overweight, namely cardiovascular disease. The development of the diet-heart hypothesis in the mid twentieth century led to faulty but long-held beliefs that dietary intake of saturated fat led to heart disease. Saturated fat can lead to increased LDL cholesterol levels, and elevated plasma cholesterol levels have been shown to be a risk factor for cardiovascular disease; however, the correlative nature of their association does not assign causation. Advances in understanding the role of various lipoprotein particles and their atherogenic risk have been helpful for understanding how different dietary components may impact CVD risk. Numerous meta-analyses and systematic reviews of both the historical and current literature reveals that the diet-heart hypothesis was not, and still is not, supported by the evidence. There appears to be no consistent benefit to all-cause or CVD mortality from the reduction of dietary saturated fat. Further, saturated fat has been shown in some cases to have an inverse relationship with obesity-related type 2 diabetes. Rather than focus on a single nutrient, the overall diet quality and elimination of processed foods, including simple carbohydrates, would likely do more to improve CVD and overall health. It is in the best interest of the American public to clarify dietary guidelines to recognize that dietary saturated fat is not the villain we once thought it was.

Abstract 453: Sestrin1 is Required to Maintain Plasma Cholesterol Homeostasis During Cholesterol Feeding

Elevated plasma cholesterol is an established risk factor in the development of heart disease; however, the detailed mechanisms controlling plasma cholesterol levels are complex and under active investigation. Integrating mouse liver global co-expression networks along with human lipid genome-wide association study (GWAS) data, we identified Sestrin1 as a candidate gene associated with cholesterol in mice and humans. To test the role of Sestrin1 in cholesterol metabolism, we performed in vitro and in vivo studies to determine its sensitivity to cholesterol and influence on cellular and plasma cholesterol levels. In vitro , Sestrin1 mRNA is upregulated following cellular cholesterol depletion with methyl-β-cyclodextrin for 4 hours in AML12 hepatocyte cells. This upregulation is blocked when cholesterol complexes or Low-Density Lipoprotein (LDL)-cholesterol is supplemented back into the media. In vivo , hepatic Sestrin1 mRNA is downregulated when mice after feeding a 0.2% cholesterol diet for 8 weeks. In contrast, treatment of mice with 0.02% Lovastatin for 1 week results in upregulation of hepatic Sestrin1 mRNA. Consistent with transcriptional regulation by cholesterol in vitro and in vivo , siRNA knockdown of Sterol regulatory element-binding protein 2 (Srebp2) represses Sestrin1 transcription and prevents the transcriptional regulation of Sestrin1 by cholesterol. Knockdown of Sestrin1 with siRNA in AML12 cells results in cellular cholesterol accumulation along with altered cholesterol related gene expression, indicating Sestrin1 can regulate cholesterol metabolism in vitro . In vivo , homozygote or heterozygote Sestrin1 knockout mice fed a 0.2% cholesterol diet for 4 weeks show elevated plasma cholesterol levels compared to littermate control mice. Our results establish Sestrin1 as a Srebp2 target gene that is capable of modulating cellular cholesterol levels in vitro and regulating plasma cholesterol homeostasis in vivo .

Cytokine-mediated inflammation mediates painful neuropathy from metabolic syndrome.

Painful neuropathy (PN) is a prevalent condition in patients with metabolic syndrome (MetS). However, the pathogenic mechanisms of metabolic syndrome-associated painful neuropathy (MetSPN) remain unclear. In the current study, high-fat-fed mice (HF mice) were used to study MetSPN. HF mice developed MetS phenotypes, including increased body weight, elevated plasma cholesterol levels, and insulin resistance in comparison with control-fat-fed (CF) mice. Subsequently, HF mice developed mechanical allodynia and thermal hyperalgesia in hind paws after 8 wk of diet treatment. These pain behaviors coincided with increased densities of nociceptive epidermal nerve fibers and inflammatory cells such as Langerhans cells and macrophages in hind paw skin. To study the effect of MetS on profiles of cytokine expression in HF mice, we used a multiplex cytokine assay to study the protein expression of 12 pro-inflammatory and anti-inflammatory cytokines in dorsal root ganglion and serum samples. This method detected the elevated levels of proinflammatory cytokines, including tumor necrosis factor (TNF)-α, and interleukin (IL)-6, IL-1β as well as reduced anti-inflammatory IL-10 in lumbar dorsal root ganglia (LDRG) of HF mice. Intraperitoneal administration of IL-10 reduced the upregulation of pro-inflammatory cytokines and alleviated pain behaviors in HF mice without affecting MetS phenotypes. Our findings suggested targeting HF-induced cytokine dysregulation could be an effective strategy for treating MetSPN.

Measurement of Intestinal and Peripheral Cholesterol Fluxes by a Dual-Tracer Balance Method.

Long-term elevated plasma cholesterol levels put individuals at risk for developing atherosclerosis. Plasma cholesterol levels are determined by the balance between cholesterol input and output fluxes. Here we describe in detail the methodology to determine the different cholesterol fluxes in mice. The percentage of absorbed cholesterol is calculated from a stable isotope-based double-label method. Cholesterol synthesis is calculated from MIDA after 13 C-acetate enrichment. Cholesterol is removed from the body via the feces. The fecal excretion route is either biliary or non-biliary. The non-biliary route is dominated by trans-intestinal cholesterol efflux, or TICE. Biliary excretion of cholesterol is measured by collecting bile. Non-biliary excretion is calculated by computational modeling. In this article, we describe methods and procedures to measure and calculate dietary intake of cholesterol, fractional cholesterol absorption, fecal neutral sterol output, biliary cholesterol excretion, TICE, cholesterol synthesis, peripheral fluxes, and whole-body cholesterol balance. © 2016 by John Wiley & Sons, Inc.

Identification and molecular characterisation of Lausanne Institutional Biobank participants with familial hypercholesterolaemia - a proof-of-concept study.

We aimed to identify familial hypercholesterolaemia mutation carriers among participants to the Lausanne Institutional Biobank (BIL). Our experimental workflow was designed as a proof-of-concept demonstration of the resources and services provided by our integrated institutional clinical research support platform. Familial hypercholesterolaemia was used as a model of a relatively common yet often underdiagnosed and inadequately treated Mendelian disease. Clinical and laboratory information was extracted from electronic hospital records. Patients were selected using elevated plasma cholesterol levels (total cholesterol ≥7.5 mM or low-density lipoprotein cholesterol ≥5 mM), premature coronary artery disease status and age (18-60 yr) as main inclusion criteria. LDLR, APOB and PCSK9 were analysed by high-throughput DNA sequencing. The most relevant mutations were confirmed by Sanger sequencing. Of 23 737 patients contacted by the BIL, 17 760 individuals consented to participate and 13 094 wished to be recontacted if there were findings requiring clinical action. Plasma cholesterol records were available for 5111 participants, of whom 94 were selected for genetic screening. Twenty-five of the tested patients presented with premature coronary artery disease while 69 had no such diagnosis. Seven heterozygous carriers of eight rare coding missense variants were identified. Three mutations were pathogenic (APOB p.R3527Q) or likely pathogenic (LDLR p.C27W, LDLR p.P526S) for hypercholesterolaemia, while the others were either benign or of unknown significance. One patient was a double heterozygote for variants APOB p.R3527Q and LDLR p.P526S. This work illustrates how clinical and translational research can benefit from a dedicated platform integrating both a hospital-based biobank and a data support team.

Role of Endolysosomes in Skeletal Muscle Pathology Observed in a Cholesterol-Fed Rabbit Model of Alzheimer’s Disease

Deficits in skeletal muscles contribute not only to the functional decline in people living with Alzheimer’s disease (AD), but also to AD pathogenesis. We have shown that endolysosome dysfunction plays an important role in the development of AD pathological features in a cholesterol-fed rabbit model of AD. Interestingly we observed in skeletal muscle from the rabbit AD model increased deposition of Aβ, phosphorylated tau, and ubiquitin. Here, we tested the hypothesis that endolysosome dysfunction commonly occurs in skeletal muscle and brain in this rabbit model of AD. In skeletal muscle of rabbits fed a 2% cholesterol-enriched diet for 12 weeks we observed the presence of abnormally enlarged endolysosomes, in which were increased accumulations of free cholesterol and multiple AD marker proteins subject to misfolding and aggregation including Aβ, phosphorylated tau, and ubiquitin. Moreover, in skeletal muscle of rabbits fed the cholesterol-enriched diet we observed decreased specific activities of three different lysosome enzymes. Our results suggest that elevated levels of plasma cholesterol can disturb endolysosome structure and function as well as promote the development of AD-like pathological features in skeletal muscle and that these organellar changes might contribute to the development of skeletal muscle deficits in AD.

A Single-Nucleotide Polymorphism in C12orf43 Region is Associated with the Risk of Coronary Artery Disease in a Pakistani Cohort.

Coronary artery disease (CAD) is one of the leading public health problems associated with mortality and morbidity in the world. It is a complex disorder influenced by both genetic and environmental factors. Atherosclerosis and elevated levels of plasma cholesterol contribute to increased risk for CAD. Other risk factors include age, hypertension, obesity, diabetes, smoking, and family history. Previous genetic studies have identified multiple polymorphisms in various genes to be associated with the risk of CAD in different populations. We aimed to examine the association of MRAS/rs9818870 and C12orf43/rs2258287 polymorphisms with the risk of CAD in a Pakistani sample. A total of 200 samples (100 cases and 100 controls) was analyzed by Allele-specific PCR. Genotypes were determined by agarose gel electrophoresis. In the current study, locus C12orf43/rs2258287 was found to be associated with the risk of CAD in the studied Pakistani cohort (OR 0.18; CI 0.08-0.37; p=0.0001) while no association was observed for MRAS/rs9818870 (OR 1.34; CI 0.65-2.76; p=0.42). In conclusion, the rs2258287 SNP may play an important role in the progression of CAD in the Pakistani subjects. However, future studies should be done on a larger sample size to fully establish its exact role in CAD.

Lipoprotein-X in a Patient with Lymphoplasmacytic Sclerosing Cholangitis: An Unusual Cause of Secondary Hypercholesterolemia

ABSTRACT Objective: To describe the presence of lipoprotein-X in a patient with obstructive liver disease and review the available literature on secondary hypercholesteremia occurring in the presence of lipoprotein-X. Methods: Reported is the case of a 40-year-old man who presented with severe hypercholesterolemia due to obstructive cholestasis secondary to lymphoplasmacytic sclerosing cholangitis. A literature search was conducted through PubMed for references from 1976 to 2013 regarding the appearance of lipoprotein-X in plasma secondary to cholestasis. Twenty-eight articles were found that addressed the physiology, pathogenesis, complications, or treatments of lipoprotein-X in the context of cholestasis. Results: Severe hypercholesterolemia was found in a patient with lymphoplasmacytic sclerosing cholangitis. His elevated plasma cholesterol level was due to the presence of lipoprotein-X, which is a particle with a density similar to low-density lipoprotein (LDL) that does not contain apolipoprotein B. ...

A Diet-Sensitive BAF60a-Mediated Pathway Links Hepatic Bile Acid Metabolism to Cholesterol Absorption and Atherosclerosis

Dietary nutrients interact with gene networks to orchestrate adaptive responses during metabolic stress. Here, we identify Baf60a as a diet-sensitive subunit of the SWI/SNF chromatin-remodeling complexes in the mouse liver that links the consumption of fat- and cholesterol-rich diet to elevated plasma cholesterol levels. Baf60a expression was elevated in the liver following feeding with a western diet. Hepatocyte-specific inactivation of Baf60a reduced bile acid production and cholesterol absorption, and attenuated diet-induced hypercholesterolemia and atherosclerosis in mice. Baf60a stimulates expression of genes involved in bile acid synthesis, modification, and transport through a CAR/Baf60a feedforward regulatory loop. Baf60a is required for the recruitment of the SWI/SNF chromatin-remodeling complexes to facilitate an activating epigenetic switch on target genes. These studies elucidate a regulatory pathway that mediates the hyperlipidemic and atherogenic effects of western diet consumption.

LDL Receptor-Related Protein-1 (LRP1) Regulates Cholesterol Accumulation in Macrophages.

Within the circulation, cholesterol is transported by lipoprotein particles and is taken up by cells when these particles associate with cellular receptors. In macrophages, excessive lipoprotein particle uptake leads to foam cell formation, which is an early event in the development of atherosclerosis. Currently, mechanisms responsible for foam cell formation are incompletely understood. To date, several macrophage receptors have been identified that contribute to the uptake of modified forms of lipoproteins leading to foam cell formation, but the contribution of the LDL receptor-related protein 1 (LRP1) to this process is not known. To investigate the role of LRP1 in cholesterol accumulation in macrophages, we generated mice with a selective deletion of LRP1 in macrophages on an LDL receptor (LDLR)-deficient background (macLRP1-/-). After feeding mice a high fat diet for 11 weeks, peritoneal macrophages isolated from Lrp +/+ mice contained significantly higher levels of total cholesterol than those from macLRP1-/- mice. Further analysis revealed that this was due to increased levels of cholesterol esters. Interestingly, macLRP1-/- mice displayed elevated plasma cholesterol and triglyceride levels resulting from accumulation of large, triglyceride-rich lipoprotein particles in the circulation. This increase did not result from an increase in hepatic VLDL biosynthesis, but rather results from a defect in catabolism of triglyceride-rich lipoprotein particles in macLRP1-/- mice. These studies reveal an important in vivo contribution of macrophage LRP1 to cholesterol homeostasis.

The Effect of Klotho Treatment on Atherogenesis, Blood Pressure, and Metabolic Parameters in Experimental Rodent Models.

Klotho is a transmembrane protein, expressed mainly in the kidneys and the choroid plexus. The extracellular domain of klotho is composed of 2 internal repeats, KL1 and KL2, which can be cleaved and act as hormones. Klotho-deficient mice develop a phenotype resembling human aging. Laboratory and clinical data suggest a favorable effect of klotho on atherosclerosis, high blood pressure, and metabolic syndrome. Therefore, we aimed to study the effect of klotho treatment on atherogenesis, blood pressure, and metabolic parameters in experimental rodent models. Fructose-fed Sprague-Dawley rats (metabolic syndrome model) and apolipoprotein E (apoE -/-) knock-out mice (atherosclerosis model) were treated with either klotho or its active domain KL1. In apoE -/- mice, klotho unexpectedly elevated plasma cholesterol and triglyceride levels compared to the control group. Yet, it did not increase the aortic sinus atherosclerotic lesion area. In fructose-fed Sprague-Dawley rats, klotho treatment did not lower blood pressure or plasma triglyceride levels. Although KL1 treatment did not lower blood pressure or plasma insulin levels, it significantly reduced the elevation of total plasma triglyceride levels (from 2.3-fold to 1.6-fold, p<0.05) due to lower triglyceride-rich VLDL levels. Klotho did not show any beneficial effects on atherosclerosis and components of the metabolic syndrome and was associated with increased plasma cholesterol levels. On the other hand, treatment with KL1 may lower plasma triglyceride levels independent of insulin. Additional studies are required in order to decipher the complex role of klotho and its active domains in the regulation of plasma lipid levels.

Abstract 116: Mechanism of ApoA-I Attenuation of Inflammation Associated with Atherosclerosis

Cytokines/chemokines and their receptors have been an important consideration when investigating the role of inflammation in atherosclerosis. In humans and animal models, monocyte recruitment and accumulation within the artery wall occurs in response to elevated plasma cholesterol levels. To mimic this process in a mouse model of atherosclerosis, our lab has utilized the LDLr-/-, ApoA-I-/- double knockout mouse. Our studies have shown that LDLr-/-, ApoA-I-/- mice have increased immune cell mobilization driving the progression of atherosclerosis when compared to LDLr-/- mice, and that treating mice with frequent, low doses (200 μg) of subcutaneous administered lipid-free apoA-I or rHDL reverses the atherogenic process. Based on these studies we wanted to investigate which inflammatory pathways were most affected by apoA-I treatment. To do this, we carried out RT-PCR to obtain the relative mRNA abundance on 40 different markers of inflammation in two genotypes of atherogenic diet fed mice. Each genotype of mice was divided into two subsets. One subset was fed an atherogenic diet for 12 weeks while the other subset received 12 weeks of diet and subcutaneous injections of 200 μg of apoA-I for the last 6 weeks of the study. Spleen was isolated from all animals and their inflammatory gene mRNA expression examined. Most significantly both genotypes showed a large decrease in IL-3 mRNA expression but also showed a significant increase in CD163 mRNA expression with apoA-I treatment. Decrease in splenic IL-3 expression is a significant mediator of inflammation regression because of the role IL-3 plays in monocyte production inside the spleen. Other investigators have shown that myeloid cells reserved in the spleen give rise to monocytes in an IL-3 rich environment. IL-3 develops and maintains circulating monocytes, which may accumulate in the arteries during atherosclerosis. This suggests apoA-I treatment affects IL-3 levels in the spleen, and thus the amount of monocytes in circulation. An increase in CD163 mRNA expression in the spleen implies higher accumulation of monocytes inside the spleen, and out of circulation. This suggests that apoA-1 treatment can decrease the amount of monocytes in the arteries, which can be a result of reverse in the atherogenic process.