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Publication
Journal: Circulation
January/15/2008
Abstract
BACKGROUND: Higher levels of red blood cell distribution width (RDW) may be associated with adverse outcomes in patients with heart failure. We examined the association between RDW and the risk of all-cause mortality and adverse cardiovascular outcomes in a population of people with coronary disease who were free of heart failure at baseline. METHODS AND RESULTS: We performed a post hoc analysis of data from the Cholesterol and Recurrent Events study. Baseline RDW was measured in 4111 participants who were randomized to receive pravastatin 40 mg daily or placebo and followed for a median of 59.7 months. We used Cox proportional hazards models to examine the association between RDW and adverse clinical outcomes. During nearly 60 months of follow-up, 376 participants died. A significant association was noted between baseline RDW level and the adjusted risk of all-cause mortality (hazard ratio per percent increase in RDW, 1.14; 95% confidence interval, 1.05 to 1.24). After categorization based on quartile of baseline RDW and further adjustment for hematocrit and other cardiovascular risk factors, a graded independent relation between RDW and death was observed (P for trend=0.001). For instance, participants with RDW in the highest quartile had an adjusted hazard ratio for death of 1.78 (95% confidence interval, 1.28 to 2.47) compared with those in the lowest quartile. Higher levels of RDW were also associated with increased risk of coronary death/nonfatal myocardial infarction, new symptomatic heart failure, and stroke. CONCLUSIONS: We found a graded independent relation between higher levels of RDW and the risk of death and cardiovascular events in people with prior myocardial infarction but no symptomatic heart failure at baseline.
Publication
Journal: New England Journal of Medicine
December/6/2009
Abstract
BACKGROUND
Treatment added to statin monotherapy to further modify the lipid profile may include combination therapy to either raise the high-density lipoprotein (HDL) cholesterol level or further lower the low-density lipoprotein (LDL) cholesterol level.
METHODS
We enrolled patients who had coronary heart disease or a coronary heart disease risk equivalent, who were receiving long-term statin therapy, and in whom an LDL cholesterol level under 100 mg per deciliter (2.6 mmol per liter) and an HDL cholesterol level under 50 mg per deciliter for men or 55 mg per deciliter for women (1.3 or 1.4 mmol per liter, respectively) had been achieved. The patients were randomly assigned to receive extended-release niacin (target dose, 2000 mg per day) or ezetimibe (10 mg per day). The primary end point was the between-group difference in the change from baseline in the mean common carotid intima-media thickness after 14 months. The trial was terminated early, on the basis of efficacy, according to a prespecified analysis conducted after 208 patients had completed the trial.
RESULTS
The mean HDL cholesterol level in the niacin group increased by 18.4% over the 14-month study period, to 50 mg per deciliter (P < 0.001), and the mean LDL cholesterol level in the ezetimibe group decreased by 19.2%, to 66 mg per deciliter (1.7 mmol per liter) (P < 0.001). Niacin therapy significantly reduced LDL cholesterol and triglyceride levels; ezetimibe reduced the HDL cholesterol and triglyceride levels. As compared with ezetimibe, niacin had greater efficacy regarding the change in mean carotid intima-media thickness over 14 months (P = 0.003), leading to significant reduction of both mean (P = 0.001) and maximal carotid intima-media thickness (P < or = 0.001 for all comparisons). Paradoxically, greater reductions in the LDL cholesterol level in association with ezetimibe were significantly associated with an increase in the carotid intima-media thickness (R = -0.31, P < 0.001). The incidence of major cardiovascular events was lower in the niacin group than in the ezetimibe group (1% vs. 5%, P = 0.04 by the chi-square test).
CONCLUSIONS
This comparative-effectiveness trial shows that the use of extended-release niacin causes a significant regression of carotid intima-media thickness when combined with a statin and that niacin is superior to ezetimibe. (ClinicalTrials.gov number, NCT00397657.)
Publication
Journal: Journal of Clinical Investigation
July/11/2002
Abstract
We recently showed that human skin fibroblasts internalize fluorescent analogues of the glycosphingolipids lactosylceramide and globoside almost exclusively by a clathrin-independent mechanism involving caveolae. In contrast, a sphingomyelin analogue is internalized approximately equally via clathrin-dependent and caveolar routes. Here, we further characterized the caveolar pathway for glycosphingolipids, showing that Golgi targeting of sphingolipids internalized via caveolae required microtubules and phosphoinositol 3-kinases and was inhibited in cells expressing dominant-negative Rab7 and Rab9 constructs. In addition, overexpression of wild-type Rab7 or Rab9 (but not Rab11) in Niemann-Pick type C (NP-C) lipid storage disease fibroblasts resulted in correction of lipid trafficking defects, including restoration of Golgi targeting of fluorescent lactosylceramide and endogenous GM(1) ganglioside, and a dramatic reduction in intracellular cholesterol stores. Our results demonstrate a role for Rab7 and Rab9 in the Golgi targeting of glycosphingolipids and suggest a new therapeutic approach for restoring normal lipid trafficking in NP-C cells.
Publication
Journal: Journal of Clinical Investigation
June/20/2011
Abstract
Dyslipidemia is an independent risk factor for type 2 diabetes, although exactly which of the many plasma lipids contribute to this remains unclear. We therefore investigated whether lipid profiling can inform diabetes prediction by performing liquid chromatography/mass spectrometry-based lipid profiling in 189 individuals who developed type 2 diabetes and 189 matched disease-free individuals, with over 12 years of follow up in the Framingham Heart Study. We found that lipids of lower carbon number and double bond content were associated with an increased risk of diabetes, whereas lipids of higher carbon number and double bond content were associated with decreased risk. This pattern was strongest for triacylglycerols (TAGs) and persisted after multivariable adjustment for age, sex, BMI, fasting glucose, fasting insulin, total triglycerides, and HDL cholesterol. A combination of 2 TAGs further improved diabetes prediction. To explore potential mechanisms that modulate the distribution of plasma lipids, we performed lipid profiling during oral glucose tolerance testing, pharmacologic interventions, and acute exercise testing. Levels of TAGs associated with increased risk for diabetes decreased in response to insulin action and were elevated in the setting of insulin resistance. Conversely, levels of TAGs associated with decreased diabetes risk rose in response to insulin and were poorly correlated with insulin resistance. These studies identify a relationship between lipid acyl chain content and diabetes risk and demonstrate how lipid profiling could aid in clinical risk assessment.
Publication
Journal: Medical Care
October/7/2010
Abstract
BACKGROUND
One approach postulated to improve the provision of health care is effective utilization of team-based care including pharmacists.
OBJECTIVE
The objective of this study was to conduct a comprehensive systematic review with focused meta-analyses to examine the effects of pharmacist-provided direct patient care on therapeutic, safety, and humanistic outcomes.
METHODS
The following databases were searched from inception to January 2009: NLM PubMed; Ovid/MEDLINE; ABI/INFORM; Health Business Fulltext Elite; Academic Search Complete; International Pharmaceutical Abstracts; PsycINFO; Cochrane Database of Systematic Reviews; National Guideline Clearinghouse; Database of Abstracts of Reviews of Effects; ClinicalTrials.gov; LexisNexis Academic Universe; and Google Scholar. Studies selected included those reporting pharmacist-provided care, comparison groups, and patient-related outcomes. Of these, 56,573 citations were considered. Data were extracted by multidisciplinary study review teams. Variables examined included study characteristics, pharmacists' interventions/services, patient characteristics, and study outcomes. Data for meta-analyses were extracted from randomized controlled trials meeting meta-analysis criteria.
RESULTS
A total of 298 studies were included. Favorable results were found in therapeutic and safety outcomes, and meta-analyses conducted for hemoglobin A1c, LDL cholesterol, blood pressure, and adverse drug events were significant (P < 0.05), favoring pharmacists' direct patient care over comparative services. Results for humanistic outcomes were favorable with variability. Medication adherence, patient knowledge, and quality of life-general health meta-analyses were significant (P < 0.05), favoring pharmacists' direct patient care.
CONCLUSIONS
Pharmacist-provided direct patient care has favorable effects across various patient outcomes, health care settings, and disease states. Incorporating pharmacists as health care team members in direct patient care is a viable solution to help improve US health care.
Publication
Journal: Circulation Journal
January/31/2005
Abstract
BACKGROUND
The metabolic syndrome, a cluster of abdominal obesity, dyslipidemia, hypertension and hyperglycemia, is a common basis for atherosclerotic vascular diseases in industrial countries exposed to overnutrition. Adiponectin is an adipose-derived plasma protein with anti-atherogenic and insulin-sensitizing activities.
RESULTS
A total of 661 Japanese adults (479 men, 53+/-10 years; 182 women 56+/-10 years) were enrolled. Plasma adiponectin concentrations correlated negatively with waist circumference, visceral fat area, serum triglyceride concentration, fasting plasma glucose, fasting plasma insulin, and systolic and diastolic blood pressure in both sexes. A positive correlation was found between plasma adiponectin and high-density lipoprotein cholesterol concentrations in both sexes. The mean number of components of the metabolic syndrome increased as the plasma adiponectin concentration decreased: 2.57+/-1.34 for men and 2.00+/-1.51 for women with adiponectin concentrations <4.0 microg/ml. In all, 52.3% of men and 37.5% of women with adiponectin concentrations <4.0 microg/ml fulfilled the criteria for metabolic syndrome.
CONCLUSIONS
Hypoadiponectinemia is closely associated with the clinical phenotype of the metabolic syndrome and measuring the plasma concentration of adiponectin may be useful for management of the metabolic syndrome.
Publication
Journal: The Lancet
March/9/2011
Abstract
BACKGROUND
Data for trends in serum cholesterol are needed to understand the effects of its dietary, lifestyle, and pharmacological determinants; set intervention priorities; and evaluate national programmes. Previous analyses of trends in serum cholesterol were limited to a few countries, with no consistent and comparable global analysis. We estimated worldwide trends in population mean serum total cholesterol.
METHODS
We estimated trends and their uncertainties in mean serum total cholesterol for adults 25 years and older in 199 countries and territories. We obtained data from published and unpublished health examination surveys and epidemiological studies (321 country-years and 3·0 million participants). For each sex, we used a Bayesian hierarchical model to estimate mean total cholesterol by age, country, and year, accounting for whether a study was nationally representative.
RESULTS
In 2008, age-standardised mean total cholesterol worldwide was 4·64 mmol/L (95% uncertainty interval 4·51-4·76) for men and 4·76 mmol/L (4·62-4·91) for women. Globally, mean total cholesterol changed little between 1980 and 2008, falling by less than 0·1 mmol/L per decade in men and women. Total cholesterol fell in the high-income region consisting of Australasia, North America, and western Europe, and in central and eastern Europe; the regional declines were about 0·2 mmol/L per decade for both sexes, with posterior probabilities of these being true declines 0·99 or greater. Mean total cholesterol increased in east and southeast Asia and Pacific by 0·08 mmol/L per decade (-0·06 to 0·22, posterior probability=0·86) in men and 0·09 mmol/L per decade (-0·07 to 0·26, posterior probability=0·86) in women. Despite converging trends, serum total cholesterol in 2008 was highest in the high-income region consisting of Australasia, North America, and western Europe; the regional mean was 5·24 mmol/L (5·08-5·39) for men and 5·23 mmol/L (5·03-5·43) for women. It was lowest in sub-Saharan Africa at 4·08 mmol/L (3·82-4·34) for men and 4·27 mmol/L (3·99-4·56) for women.
CONCLUSIONS
Nutritional policies and pharmacological interventions should be used to accelerate improvements in total cholesterol in regions with decline and to curb or prevent the rise in Asian populations and elsewhere. Population-based surveillance of cholesterol needs to be improved in low-income and middle-income countries.
BACKGROUND
Bill & Melinda Gates Foundation and WHO.
Publication
Journal: Journal of Lipid Research
November/2/1989
Abstract
Epidemiological studies in Greenland Eskimos led to the hypothesis that marine oils rich in n-3 fatty acids (also referred to as omega (omega)-3 fatty acids) are hypolipidemic and ultimately antiatherogenic. Metabolically controlled trials in which large amounts of fish oil were fed to normal volunteers and hyperlipidemic patients showed that these fatty acids (FAs) are effective at lowering plasma cholesterol and triglyceride levels. Although more recent trials using smaller, more practical doses of fish oil supplements have confirmed the hypotriglyceridemic effect, they have shown little effect on total cholesterol levels; hypertriglyceridemic patients have even experienced increases in low density lipoprotein cholesterol (LDL-C) levels of 10-20% while taking n-3 FA supplements. Discrepancies among fish oil studies regarding the effects of n-3 FAs on LDL-C levels may be understood by noting that, in the majority of studies reporting reductions in LDL-C levels, saturated fat intake was lowered when switching from the control diet to the fish oil diet. When fish oil is fed and saturated fat intake is constant, LDL-C levels either do not change or may increase. Levels of high density lipoprotein cholesterol have been found to increase slightly (about 5-10%) with fish oil intake. Plasma apolipoprotein levels change in concert with their associated lipoprotein cholesterol levels. Although the decrease in triglyceride levels appears to result from an inhibition in hepatic triglyceride synthesis, the mechanisms leading to the increases in LDL and HDL have not been determined. Finally, fatty fish or linolenic acid may serve as alternative sources of long-chain n-3 FAs, but further studies will be needed to document their hypolipidemic and/or antiatherogenic effects.
Authors
Publication
Journal: Proceedings of the National Academy of Sciences of the United States of America
May/23/1989
Abstract
Tissue factor (TF)-producing cells were identified in normal human vessels and atherosclerotic plaques by in situ hybridization and immunohistochemistry using a specific riboprobe for TF mRNA and a polyclonal antibody directed against human TF protein. TF mRNA and protein were absent from endothelial cells lining normal internal mammary artery and saphenous vein samples. In normal vessels TF was found to be synthesized in scattered cells present in the tunica media as well as fibroblast-like adventitial cells surrounding vessels. Atherosclerotic plaques contained many cells synthesizing TF mRNA and protein. Macrophages present as foam cells and monocytes adjacent to the cholesterol clefts contained TF mRNA and protein, as did mesenchymal-appearing intimal cells. Significant TF protein staining was found deposited in the extracellular matrix surrounding mRNA-positive cells adjacent to the cholesterol clefts and within the necrotic cores. These results suggest that deposition of TF protein in the matrix of the necrotic core of the atherosclerotic plaque may contribute to the hyperthrombotic state of human atherosclerotic vessels.
Publication
Journal: JAMA - Journal of the American Medical Association
June/18/1990
Abstract
Although type II diabetes is associated with both microvascular and macrovascular complications, duration of diabetes and severity of glycemia are strongly associated only with the former. Since prediabetic individuals are hyperinsulinemia, and since hyperinsulinemia may be a cardiovascular risk factor, we hypothesized that prediabetic individuals might have an atherogenic pattern of risk factors even before the onset of clinical diabetes, thereby explaining the relative lack of an association of macrovascular complications with either glycemic severity or disease duration. We documented the cardiovascular risk factor status of 614 initially nondiabetic Mexican Americans who later participated in an 8-year follow-up of the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. Individuals who were nondiabetic at the time of baseline examination, but who subsequently developed type II diabetes (ie, confirmed prediabetic subjects, n = 43), had higher levels of total and low-density lipoprotein cholesterol, triglyceride, fasting glucose and insulin, 2-hour glucose, body mass index, and blood pressure, and lower levels of high-density lipoprotein cholesterol than subjects who remained nondiabetic (n = 571). Most of these differences persisted after adjustment for obesity and/or level of glycemia, but were abolished after adjustment for fasting insulin concentration. When subjects with impaired glucose tolerance at baseline (n = 106) were eliminated, the more atherogenic pattern of cardiovascular risk factors was still evident (and statistically significant) among initially normoglycemic prediabetic subjects. These results indicate that prediabetic subjects have an atherogenic pattern of risk factors (possibly caused by obesity, hyperglycemia, and especially hyperinsulinemia), which may be present for many years and may contribute to the risk of macrovascular disease as much as the duration of clinical diabetes itself.
Publication
Journal: Neuroepidemiology
May/27/1998
Abstract
The epsilon 4 allele of the apolipoprotein E (apoE) is associated with Alzheimer's disease (AD) and also with elevated serum total cholesterol and low-density lipoprotein levels. However, the interrelationships between apoE genotype, plasma cholesterol levels and AD risk have been studied very little. We examined the possible role of serum total cholesterol in the pathogenesis of AD in a population-based sample of 444 men, aged 70-89 years, who were survivors of the Finnish cohorts of the Seven Countries Study. Previous high serum cholesterol level (mean level>> or = 6.5 mmol/l) was a significant predictor of the prevalence of AD (odds ratio = 3.1; 95% confidence interval = 1.2, 8.5) after controlling for age and the presence of apoE epsilon 4 allele. In men who subsequently developed AD the cholesterol level decreased before the clinical manifestations of AD. We conclude that high serum total cholesterol may be an independent risk factor for AD and some of the effect of the apoE epsilon 4 allele on risk of AD might be mediated through high serum cholesterol.
Publication
Journal: Neuropathology and Applied Neurobiology
May/3/2011
Abstract
This review of age-related brain microvascular pathologies focuses on topics studied by this laboratory, including anatomy of the blood supply, tortuous vessels, venous collagenosis, capillary remnants, vascular density and microembolic brain injury. Our studies feature thick sections, large blocks embedded in celloidin, and vascular staining by alkaline phosphatase. This permits study of the vascular network in three dimensions, and the differentiation of afferent from efferent vessels. Current evidence suggests that there is decreased vascular density in ageing, Alzheimer's disease and leukoaraiosis, and cerebrovascular dysfunction precedes and accompanies cognitive dysfunction and neurodegeneration. A decline in cerebrovascular angiogenesis may inhibit recovery from hypoxia-induced capillary loss. Cerebral blood flow is inhibited by tortuous arterioles and deposition of excessive collagen in veins and venules. Misery perfusion due to capillary loss appears to occur before cell loss in leukoaraiosis, and cerebral blood flow is also reduced in the normal-appearing white matter. Hypoperfusion occurs early in Alzheimer's disease, inducing white matter lesions and correlating with dementia. In vascular dementia, cholinergic reductions are correlated with cognitive impairment, and cholinesterase inhibitors have some benefit. Most lipid microemboli from cardiac surgery pass through the brain in a few days, but some remain for weeks. They can cause what appears to be a type of vascular dementia years after surgery. Donepezil has shown some benefit. Emboli, such as clots, cholesterol crystals and microspheres can be extruded through the walls of cerebral vessels, but there is no evidence yet that lipid emboli undergo such extravasation.
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Publication
Journal: Science
December/15/2013
Abstract
Hypercholesterolemia is a risk factor for estrogen receptor (ER)-positive breast cancers and is associated with a decreased response of tumors to endocrine therapies. Here, we show that 27-hydroxycholesterol (27HC), a primary metabolite of cholesterol and an ER and liver X receptor (LXR) ligand, increases ER-dependent growth and LXR-dependent metastasis in mouse models of breast cancer. The effects of cholesterol on tumor pathology required its conversion to 27HC by the cytochrome P450 oxidase CYP27A1 and were attenuated by treatment with CYP27A1 inhibitors. In human breast cancer specimens, CYP27A1 expression levels correlated with tumor grade. In high-grade tumors, both tumor cells and tumor-associated macrophages exhibited high expression levels of the enzyme. Thus, lowering circulating cholesterol levels or interfering with its conversion to 27HC may be a useful strategy to prevent and/or treat breast cancer.
Publication
Journal: American Journal of Preventive Medicine
June/20/2000
Abstract
BACKGROUND
Self-reported data are commonly used to estimate the prevalence of health conditions and the use of preventive health services in the population, but the validity of such data is often questioned.
METHODS
The Behavioral Risk Factor Survey (BRFS) was admin istered by telephone to a stratified, random sample of health maintenanc e organization (HMO) subscribers in Colorado in 1993, and self-reports w ere compared with HMO medical records for 599 adults aged >21. Sensitivity and specificity were calculated for three chronic conditions and use of six preventive services.
RESULTS
Sensitivity was highest for hypertension (83%), moderate for diabetes (73%), and lowest for hypercholesterolemia (59%); specificity was >80% for all three conditions. Sensitivity ranged from 86% to 99% for influenza immunization, clinical breast examination, blood cholesterol screening, mammography, Pap test, and blood pressure screening; specificity was <75% for all preventive services.
CONCLUSIONS
Self-reports are reasonably accurate for certain chronic conditions and for routine screening exams and can provide a useful estimate for broad measures of population prevalence.
Publication
Journal: Journal of Clinical Investigation
December/17/2006
Abstract
Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a member of the proteinase K subfamily of subtilases that reduces the number of LDL receptors (LDLRs) in liver through an undefined posttranscriptional mechanism. We show that purified PCSK9 added to the medium of HepG2 cells reduces the number of cell-surface LDLRs in a dose- and time-dependent manner. This activity was approximately 10-fold greater for a gain-of-function mutant, PCSK9(D374Y), that causes hypercholesterolemia. Binding and uptake of PCSK9 were largely dependent on the presence of LDLRs. Coimmunoprecipitation and ligand blotting studies indicated that PCSK9 and LDLR directly associate; both proteins colocalized to late endocytic compartments. Purified PCSK9 had no effect on cell-surface LDLRs in hepatocytes lacking autosomal recessive hypercholesterolemia (ARH), an adaptor protein required for endocytosis of the receptor. Transgenic mice overexpressing human PCSK9 in liver secreted large amounts of the protein into plasma, which increased plasma LDL cholesterol concentrations to levels similar to those of LDLR-knockout mice. To determine whether PCSK9 was active in plasma, transgenic PCSK9 mice were parabiosed with wild-type littermates. After parabiosis, secreted PCSK9 was transferred to the circulation of wild-type mice and reduced the number of hepatic LDLRs to nearly undetectable levels. We conclude that secreted PCSK9 associates with the LDLR and reduces hepatic LDLR protein levels.
Publication
Journal: Proceedings of the National Academy of Sciences of the United States of America
June/21/2004
Abstract
Proprotein convertase subtilisin kexin 9 (Pcsk9) is a subtilisin serine protease with a putative role in cholesterol metabolism. Pcsk9 expression is down-regulated by dietary cholesterol, and mutations in Pcsk9 have been associated with a form of autosomal dominant hypercholesterolemia. To study the function of Pcsk9 in mice, an adenovirus constitutively expressing murine Pcsk9 (Pcsk9-Ad) was used. Pcsk9 overexpression in wild-type mice caused a 2-fold increase in plasma total cholesterol and a 5-fold increase in non-high-density lipoprotein (HDL) cholesterol, with no increase in HDL cholesterol, as compared with mice infected with a control adenovirus. Fast protein liquid chromatography analysis showed that the increase in non-HDL cholesterol was due to an increase in low-density lipoprotein (LDL) cholesterol. This effect appeared to depend on the LDL receptor (LDLR) because LDLR knockout mice infected with Pcsk9-Ad had no change in plasma cholesterol levels as compared with knockout mice infected with a control adenovirus. Furthermore, whereas overexpression of Pcsk9 had no effect on LDLR mRNA levels, there was a near absence of LDLR protein in animals overexpressing Pcsk9. These results were confirmed in vitro by the demonstration that transfection of Pcsk9 in McA-RH7777 cells caused a reduction in LDLR protein and LDL binding. In summary, these results indicate that overexpression of Pcsk9 interferes with LDLR-mediated LDL cholesterol uptake. Because Pcsk9 and LDLR are coordinately regulated by cholesterol, Pcsk9 may be involved in a novel mechanism to modulate LDLR function by an alternative pathway than classic cholesterol inhibition of sterol regulatory element binding protein-mediated transcription.
Publication
Journal: Journal of Clinical Investigation
February/7/2005
Abstract
PPARalpha, beta/delta, and gamma regulate genes involved in the control of lipid metabolism and inflammation and are expressed in all major cell types of atherosclerotic lesions. In vitro studies have suggested that PPARs exert antiatherogenic effects by inhibiting the expression of proinflammatory genes and enhancing cholesterol efflux via activation of the liver X receptor-ABCA1 (LXR-ABCA1) pathway. To investigate the potential importance of these activities in vivo, we performed a systematic analysis of the effects of PPARalpha, beta, and gamma agonists on foam-cell formation and atherosclerosis in male LDL receptor-deficient (LDLR(-/-)) mice. Like the PPARgamma agonist, a PPARalpha-specific agonist strongly inhibited atherosclerosis, whereas a PPARbeta-specific agonist failed to inhibit lesion formation. In concert with their effects on atherosclerosis, PPARalpha and PPARgamma agonists, but not the PPARbeta agonist, inhibited the formation of macrophage foam cells in the peritoneal cavity. Unexpectedly, PPARalpha and PPARgamma agonists inhibited foam-cell formation in vivo through distinct ABCA1-independent pathways. While inhibition of foam-cell formation by PPARalpha required LXRs, activation of PPARgamma reduced cholesterol esterification, induced expression of ABCG1, and stimulated HDL-dependent cholesterol efflux in an LXR-independent manner. In concert, these findings reveal receptor-specific mechanisms by which PPARs influence macrophage cholesterol homeostasis. In the future, these mechanisms may be exploited pharmacologically to inhibit the development of atherosclerosis.
Publication
Journal: Annals of Internal Medicine
July/16/2006
Abstract
BACKGROUND
While high-sensitivity C-reactive protein (hsCRP) is an independent predictor of cardiovascular risk, global risk prediction models incorporating hsCRP have not been developed for clinical use.
OBJECTIVE
To develop and compare global cardiovascular risk prediction models with and without hsCRP.
METHODS
Observational cohort study.
METHODS
U.S. female health professionals.
METHODS
Initially healthy nondiabetic women age 45 years and older participating in the Women's Health Study and followed an average of 10 years.
METHODS
Incident cardiovascular events (myocardial infarction, stroke, coronary revascularization, and cardiovascular death).
RESULTS
High-sensitivity CRP made a relative contribution to global risk at least as large as that provided by total, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) cholesterol individually, but less than that provided by age, smoking, and blood pressure. All global measures of fit improved when hsCRP was included, with likelihood-based measures demonstrating strong preference for models that include hsCRP. With use of 10-year risk categories of 0% to less than 5%, 5% to less than 10%, 10% to less than 20%, and 20% or greater, risk prediction was more accurate in models that included hsCRP, particularly for risk between 5% and 20%. Among women initially classified with risks of 5% to less than 10% and 10% to less than 20% according to the Adult Treatment Panel III covariables, 21% and 19%, respectively, were reclassified into more accurate risk categories. Although addition of hsCRP had minimal effect on the c-statistic (a measure of model discrimination) once age, smoking, and blood pressure were accounted for, the effect was nonetheless greater than that of total, LDL, or HDL cholesterol, suggesting that the c-statistic may be insensitive in evaluating risk prediction models.
CONCLUSIONS
Data were available only for women.
CONCLUSIONS
A global risk prediction model that includes hsCRP improves cardiovascular risk classification in women, particularly among those with a 10-year risk of 5% to 20%. In models that include age, blood pressure, and smoking status, hsCRP improves prediction at least as much as do lipid measures.
Publication
Journal: JAMA - Journal of the American Medical Association
July/26/2012
Abstract
BACKGROUND
Cardiovascular disease is increased in patients with human immunodeficiency virus (HIV), but the specific mechanisms are unknown.
OBJECTIVE
To assess arterial wall inflammation in HIV, using 18fluorine-2-deoxy-D-glucose positron emission tomography (18F-FDG-PET), in relationship to traditional and nontraditional risk markers, including soluble CD163 (sCD163), a marker of monocyte and macrophage activation.
METHODS
A cross-sectional study of 81 participants investigated between November 2009 and July 2011 at the Massachusetts General Hospital. Twenty-seven participants with HIV without known cardiac disease underwent cardiac 18F-FDG-PET for assessment of arterial wall inflammation and coronary computed tomography scanning for coronary artery calcium. The HIV group was compared with 2 separate non-HIV control groups. One control group (n = 27) was matched to the HIV group for age, sex, and Framingham risk score (FRS) and had no known atherosclerotic disease (non-HIV FRS-matched controls). The second control group (n = 27) was matched on sex and selected based on the presence of known atherosclerotic disease (non-HIV atherosclerotic controls).
METHODS
Arterial inflammation was prospectively determined as the ratio of FDG uptake in the arterial wall of the ascending aorta to venous background as the target-to-background ratio (TBR).
RESULTS
Participants with HIV demonstrated well-controlled HIV disease (mean [SD] CD4 cell count, 641 [288] cells/μL; median [interquartile range] HIV-RNA level, <48 [<48 to <48] copies/mL). All were receiving antiretroviral therapy (mean [SD] duration, 12.3 [4.3] years). The mean FRS was low in both HIV and non-HIV FRS-matched control participants (6.4; 95% CI, 4.8-8.0 vs 6.6; 95% CI, 4.9-8.2; P = .87). Arterial inflammation in the aorta (aortic TBR) was higher in the HIV group vs the non-HIV FRS-matched control group (2.23; 95% CI, 2.07-2.40 vs 1.89; 95% CI, 1.80-1.97; P < .001), but was similar compared with the non-HIV atherosclerotic control group (2.23; 95% CI, 2.07-2.40 vs 2.13; 95% CI, 2.03-2.23; P = .29). Aortic TBR remained significantly higher in the HIV group vs the non-HIV FRS-matched control group after adjusting for traditional cardiovascular risk factors (P = .002) and in stratified analyses among participants with undetectable viral load, zero calcium, FRS of less than 10, a low-density lipoprotein cholesterol level of less than 100 mg/dL (<2.59 mmol/L), no statin use, and no smoking (all P ≤ .01). Aortic TBR was associated with sCD163 level (P = .04) but not with C-reactive protein (P = .65) or D-dimer (P = .08) among patients with HIV.
CONCLUSIONS
Participants infected with HIV vs noninfected control participants with similar cardiac risk factors had signs of increased arterial inflammation, which was associated with a circulating marker of monocyte and macrophage activation.
Publication
Journal: JAMA - Journal of the American Medical Association
June/22/2008
Abstract
BACKGROUND
The importance of the cholesteryl ester transfer protein (CETP) pathway in coronary disease is uncertain. Study of CETP genotypes can help better understand the relevance of this pathway to lipid metabolism and disease risk.
OBJECTIVE
To assess associations of CETP genotypes with CETP phenotypes, lipid levels, and coronary risk.
METHODS
Studies published between January 1970 and January 2008 were identified through computer-based and manual searches using MEDLINE, EMBASE, BIOSIS, Science Citation Index, and the Chinese National Knowledge Infrastructure Database. Previously unreported studies were sought through correspondence with investigators.
METHODS
Relevant studies related principally to 3 common (TaqIB [rs708272], I405V [rs5882], and -629C>A [rs1800775]) and 3 uncommon (D442G [rs2303790], -631C>A [rs1800776], and R451Q [rs1800777]) CETP polymorphisms.
METHODS
Information on CETP genotypes, CETP phenotypes, lipid levels, coronary disease, and study characteristics was abstracted from publications, supplied by investigators, or both.
RESULTS
Ninety-two studies had data on CETP phenotypes, lipid levels, or both in 113,833 healthy participants, and 46 studies had data on 27,196 coronary cases and 55,338 controls. For each A allele inherited, individuals with the TaqIB polymorphism had lower mean CETP mass (-9.7%; 95% confidence interval [CI], -11.7% to -7.8%), lower mean CETP activity (-8.6%; 95% CI, -13.0% to -4.1%), higher mean high-density lipoprotein cholesterol (HDL-C) concentrations (4.5%; 95% CI, 3.8%-5.2%), and higher mean apolipoprotein A-I concentrations (2.4%; 95% CI, 1.6%-3.2%). The pattern of findings was very similar with the I405V and -629C>A polymorphisms. The combined per-allele odds ratios (ORs) for coronary disease were 0.95 (95% CI, 0.92-0.99) for TaqIB, 0.94 (95% CI, 0.89-1.00) for I405V, and 0.95 (95% CI, 0.91-1.00) for -629C>A.
CONCLUSIONS
Three CETP genotypes that are associated with moderate inhibition of CETP activity (and, therefore, modestly higher HDL-C levels) show weakly inverse associations with coronary risk. The ORs for coronary disease were compatible with the expected reductions in risk for equivalent increases in HDL-C concentration in available prospective studies.
Publication
Journal: Journal of Lipid Research
June/4/2009
Abstract
The identification and characterization of proprotein convertase subtilisin-like/kexin type 9 (PCSK9) have provided new insights into LDL metabolism and the causal role of LDL in coronary heart disease (CHD). PCSK9 is a secreted protease that mediates degradation of the LDL receptor by interacting with the extracellular domain and targeting the receptor for degradation. Individuals with loss-of-function mutations in PCSK9 have reduced plasma levels of LDL cholesterol and are protected from CHD; these observations have validated PCSK9 as a therapeutic target and suggested new approaches for the treatment and prevention of CHD.
Publication
Journal: Genes and Development
June/2/2009
Abstract
In liver, most metabolic pathways are under circadian control, and hundreds of protein-encoding genes are thus transcribed in a cyclic fashion. Here we show that rhythmic transcription extends to the locus specifying miR-122, a highly abundant, hepatocyte-specific microRNA. Genetic loss-of-function and gain-of-function experiments have identified the orphan nuclear receptor REV-ERBalpha as the major circadian regulator of mir-122 transcription. Although due to its long half-life mature miR-122 accumulates at nearly constant rates throughout the day, this miRNA is tightly associated with control mechanisms governing circadian gene expression. Thus, the knockdown of miR-122 expression via an antisense oligonucleotide (ASO) strategy resulted in the up- and down-regulation of hundreds of mRNAs, of which a disproportionately high fraction accumulates in a circadian fashion. miR-122 has previously been linked to the regulation of cholesterol and lipid metabolism. The transcripts associated with these pathways indeed show the strongest time point-specific changes upon miR-122 depletion. The identification of Pparbeta/delta and the peroxisome proliferator-activated receptor alpha (PPARalpha) coactivator Smarcd1/Baf60a as novel miR-122 targets suggests an involvement of the circadian metabolic regulators of the PPAR family in miR-122-mediated metabolic control.
Publication
Journal: PLoS ONE
January/31/2010
Abstract
BACKGROUND
Niemann-Pick type C (NPC) disease is a fatal neurodegenerative disorder caused most commonly by a defect in the NPC1 protein and characterized by widespread intracellular accumulation of unesterified cholesterol and glycosphingolipids (GSLs). While current treatment therapies are limited, a few drugs tested in Npc1(-/-) mice have shown partial benefit. During a combination treatment trial using two such compounds, N-butyldeoxynojirimycin (NB-DNJ) and allopregnanolone, we noted increased lifespan for Npc1(-/-) mice receiving only 2-hydroxypropyl-beta-cyclodextrin (CD), the vehicle for allopregnanolone. This finding suggested that administration of CD alone, but with greater frequency, might provide additional benefit.
RESULTS
Administration of CD to Npc1(-/-) mice beginning at either P7 or P21 and continuing every other day delayed clinical onset, reduced intraneuronal cholesterol and GSL storage as well as free sphingosine accumulation, reduced markers of neurodegeneration, and led to longer survival than any previous treatment regime. We reasoned that other lysosomal diseases characterized by cholesterol and GSL accumulation, including NPC disease due to NPC2 deficiency, GM1 gangliosidosis and mucopolysaccharidosis (MPS) type IIIA, might likewise benefit from CD treatment. Treated Npc2(-/-) mice showed benefits similar to NPC1 disease, however, mice with GM1 gangliosidosis or MPS IIIA failed to show reduction in storage.
CONCLUSIONS
Treatment with CD delayed clinical disease onset, reduced intraneuronal storage and secondary markers of neurodegeneration, and significantly increased lifespan of both Npc1(-/-) and Npc2(-/-) mice. In contrast, CD failed to ameliorate cholesterol or glycosphingolipid storage in GM1 gangliosidosis and MPS IIIA disease. Understanding the mechanism(s) by which CD leads to reduced neuronal storage may provide important new opportunities for treatment of NPC and related neurodegenerative diseases characterized by cholesterol dyshomeostasis.
Publication
Journal: Journal of Hepatology
September/10/2012
Abstract
It is widely known that the liver is a central organ in lipogenesis, gluconeogenesis and cholesterol metabolism. However, over the last decades, a variety of pathological conditions highlighted the importance of metabolic functions within the diseased liver. As observed in Western societies, an increase in the prevalence of obesity and the metabolic syndrome promotes pathophysiological changes that cause non-alcoholic fatty liver disease (NAFLD). NAFLD increases the susceptibility of the liver to acute liver injury and may lead to cirrhosis and hepatocellular cancer. Alterations in insulin response, β-oxidation, lipid storage and transport, autophagy and an imbalance in chemokines and nuclear receptor signaling are held accountable for these changes. Furthermore, recent studies revealed a role for lipid accumulation in inflammation and ER stress in the clinical context of liver regeneration and hepatic carcinogenesis. This review focuses on novel findings related to nuclear receptor signaling - including the vitamin D receptor and the liver receptor homolog 1 - in hepatic lipid and glucose uptake, storage and metabolism in the clinical context of NAFLD, liver regeneration, and cancer.
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