Notch signaling plays pivotal roles in the pathogenesis of vascular disease. However, little is known about its role in atherosclerosis. We sought to investigate the potential involvement of the Notch signaling in atherosclerosis.
Expression of Notch pathway components in mouse and human aorta with or without atherosclerosis plaque was examined by immuno-histochemistry. Expression of Notch target genes in young versus aged human endothelial cells (EC) was examined by PCRArray and immunoblot. In vitro loss- and gain-of-function approaches were utilized to evaluate the role of Notch signaling in inducing EC senescence and secretion of pro-inflammatory cytokines by ProteinArray. Notch gene profile was studied in 1054 blood samples of patients with coronary artery disease (CAD). Genotyping was performed using the Genome-Wide Single Nucleotide Polymorphism (SNP) Array.
Notch pathway components were upregulated in luminal EC at atherosclerotic lesions from mouse and human aortas. In addition, the Notch pathway was activated in aged but not young human EC. Enforced Notch activation resulted in EC senescence and significantly upregulated expression of several molecules implicated in the inflammatory response (IL-6/IL-8/IL-1α/RANTES/ICAM-1). The upregulated IL-6 was partially responsible for mediating leukocyte transendothelial migration. Genetic association analysis detected, of 82 SNPs across 6 Notch pathway genes analyzed, 4 SNPs with nominal association with CAD burden.
Notch pathway is activated in luminal EC at atherosclerotic plaques and results in pro-inflammatory response and senescence of EC. Notch signaling may be linked to human CAD risk. These findings implicate a potential involvement of Notch signaling in atherosclerosis.
Notch; Endothelial cells (EC); Atherosclerosis; EC Senescence; Vascular inflammation
Retinopathy and retinal microvascular abnormalities are common in adult populations, yet few long-term predictors have been identified. We therefore examined the association between systolic blood pressure (SBP) and fasting plasma glucose, assessed over 18 years, with retinopathy and retinal vascular caliber in 2,066 Carotid MRI participants, an Atherosclerosis Risk in Communities ancillary study.
Retinopathy and retinal vascular caliber were assessed by retinal photography. Confounder-adjusted weighted regression models were used to examine exposures defined as cumulative, long-term prospective, concurrent, and 18-year change.
Long-term prospective (prevalence odds ratio (POR) per 10 mmHg: 1.14 (95% CI: 1.01, 1.30)) and cumulative (POR per 10 mmHg: 1.30 (95% CI: 1.09, 1.56) effects spanning approximately 18 years were found for SBP and retinopathy. The strongest long-term prospective association for plasma glucose and retinopathy was identified at the baseline visit (POR per 10 mg/dl: 1.26 (95% CI: 1.16, 1.38)); sustained glucose elevations over 18 years were also associated with prevalent retinopathy (POR per 10 mg/dl: 1.33 (95% CI: 1.24, 1.43)). Results were robust to the exclusion of participants with diabetes.
Modest and sustained long-term elevations in glucose and blood pressure are associated with retinopathy and retinal vascular caliber.
epidemiology; microvascular disease; retinopathy; glucose; blood pressure
The impact of leptin deficiency and its replacement in T1D remain unclear in the context of dyslipidemia and atherosclerosis. The current study has investigated the physiologic role of leptin in lipid metabolism and atherosclerosis in T1D.
Methods and results
The present study has employed Ins2+/Akita:apoE–/– mouse model that spontaneously develops T1D, hypercholesterolemia, and atherosclerosis. At age 13 weeks, diabetic Ins2+/Akita:apoE–/– mice showed leptin deficiency by ~92% compared with nondiabetic Ins2+/+:apoE–/– mice. From 13 weeks to 25 weeks of age, diabetic Ins2+/Akita:apoE–/– mice were treated with low-dose leptin (at 0.4 μg/g body weight daily). Leptin treatment diminished food intake by 22-27% in diabetic mice without affecting body weight and lean mass throughout the experiment. Importantly, leptin therapy substantially reduced plasma cholesterol concentrations by ~41%, especially in LDL fractions, in diabetic Ins2+/Akita:apoE-/- mice. Moreover, leptin therapy decreased atherosclerotic lesion in diabetic mice by ~62% comparable to that seen in nondiabetic mice. In addition, leptin restored repressed expression of hepatic sortilin-1, a receptor for LDL clearance, and reversed altered expression of several hepatic genes involved in lipogenesis and cholesterol synthesis characteristic of diabetic mice. These findings were accompanied by normalization of reduced hepatic expression of IRS1 and IRS2 mRNA as well as their protein levels, and improved hepatic insulin receptor signaling.
The present findings suggest that leptin administration may be useful to improve dyslipidemia and reduce atherosclerosis-related cardiovascular disease in human subjects with T1D.
type 1 diabetes; leptin; dyslipidemia; atherosclerosis
We examined serum lipids in association with carotid artery intima-media thickness (CIMT) in HIV-infected and HIV-uninfected women.
In 2003–4, among 1827 Women’s Interagency HIV Study participants, we measured CIMT and lipids (high-density lipoprotein cholesterol [HDL-c], low-density lipoprotein cholesterol [LDL-c], total cholesterol [TC], non-HDL-c). A subset of 520 treated HIV-infected women had pre-1997 lipid measures. We used multivariable linear regression to examine associations between lipids and CIMT.
In HIV-uninfected women, higher TC, LDL-c and non-HDL-c were associated with increased CIMT. Among HIV-infected women, associations of lipids with CIMT were observed in treated but not untreated women. Among the HIV-infected women treated in 2003–4, CIMT was associated both with lipids measured a decade earlier in infection, and with late lipid measurements.
Among HIV-infected women, hyperlipidemia is most strongly associated with subclinical atherosclerosis in treated women. Among treated women, the association appeared strongest early in the disease course.
cardiovascular diseases; carotid arteries; HAART; HIV; lipids
Statins inhibit cholesterol synthesis but can upregulate cholesterol absorption, with higher doses producing larger effects. Ezetimibe inhibits cholesterol absorption but also upregulates synthesis. We tested whether ezetimibe added to ongoing statin therapy would be most effective in lowering LDL-cholesterol (LDL-C) in subjects on high-potency statins and whether these effects would be related to alterations in cholesterol absorption (β-sitosterol) and synthesis (lathosterol) markers.
Hypercholesterolemic subjects (n=874) on statins received ezetimibe 10 mg/day. Plasma lipids, lathosterol, and β-sitosterol were measured at baseline and on treatment. Subjects were divided into low- (n=133), medium- (n=582), and high- (n=159) statin potency groups defined by predicted LDL-C–lowering effects of each ongoing statin type and dose (reductions of ~20-30%, ~31-45%, or ~46-55%, respectively).
The high-potency group had significantly lower baseline lathosterol (1.93 vs. 2.58 vs. 3.17 μmol/l; p <0.001) and higher baseline β-sitosterol values (6.21 vs. 4.58 vs. 4.51 μmol/l, p <0.001) than medium-/low-potency groups. Ezetimibe treatment in the high-potency group produced significantly greater reductions from baseline in LDL-C than medium-/low-potency groups (−29.1% vs. −25.0% vs. −22.7%; p <0.001) when evaluating unadjusted data. These effects and group differences were significantly (p <0.05) related to greater β-sitosterol reductions and smaller lathosterol increases. However, LDL-C reduction differences between groups were no longer significant after controlling for placebo effects, due mainly to modest LDL-C lowering by placebo in the high-potency group.
Patients on high-potency statins have the lowest levels of cholesterol synthesis markers and the highest levels of cholesterol absorption markers at baseline, and the greatest reduction in absorption markers and the smallest increases in synthesis markers with ezetimibe addition. Therefore, such patients may be good candidates for ezetimibe therapy if additional LDL-C lowering is needed.
non-cholesterol sterol; lathosterol; β-sitosterol; statin potency; dyslipidemia
Inflammation is a risk factor for coronary heart disease (CHD). A common deletion-allele in the promoter region of NFKB1 results in lower protein levels of the NF-κB p50 subunit. Recent evidence suggests that the NF-κB p50 dimer has anti-inflammatory effects. We aimed to investigate the association of the functional ATTG NFKB1 insertion/deletion variant with risk of CHD in three independent prospective studies of generally healthy men and women.
Methods and Results
The NFKB1 ins/del polymorphism was genotyped in studies of CHD nested within the Diet, Cancer and Health (DCH) study, the Health Professionals Follow-up (HPFS) and the Nurses’ Health (NHS) studies, totaling 1008, 428 and 439 cases, respectively. The minor allele frequency in the combined sample was 0.38 among controls. In a pooled analysis, the relative risk (RR) among heterozygous men and women was 1.22 (95% CI: 1.07–1.40), compared to the most common ins/ins genotype. The RR among homozygotes was 1.20 (95% CI: 0.94–1.53). There was no evidence of an allele-dosage effect, and in a dominant model the RR among del-allele carriers was 1.22 (95% CI: 1.07–1.39). The risk was similar in women and men (RR was 1.20 in women and 1.23 in men, respectively). The NFKB1 variant was not associated with plasma lipid levels, but del-carriers had lower levels of C-reactive protein.
The NFKB1 promoter variant, previously shown to cause partial depletion of NF-kB p50, was associated with a higher risk of CHD in three independent prospective studies of generally healthy Caucasians.
NFkappaB; inflammation; polymorphism; population-based
Background and Purpose
Recent findings implicating specific gene polymorphisms of the interleukin-1 superfamily gene cluster in the risk of developing athero-thrombotic disorders have generated great interest. However, to date, no prospective, genetic-epidemiological data are available.
Using DNA samples collected at baseline in a prospective cohort of 14,916 initially healthy American men, we evaluated seven gene polymorphisms within the interleukin-1 gene cluster among 599 individuals who subsequently developed athero-thrombotic event and among 599 age- and smoking-matched individuals who remained free of reported cardiovascular disease during follow-up (341 incident myocardial infarction matched case-control pairs and 258 incident ischemic stroke matched case-control pairs).
Overall, we observed little evidence of association between the polymorphisms tested and risk of incident athero-thrombotic events. Further adjustment for traditional cardiovascular risk factors yielded similar null findings. Of note, a modest association of rs1143623 with reduced risk of incident MI was found (recessive model: OR=0.455, 95%CI=0.215–0.960, uncorrected p=0.039). However, this finding was not corrected for multiple testing, and thus requires cautious interpretation.
In contrast to prior retrospective studies, our prospective data suggest that the IL-1 cluster gene variation is not associated with risk of athero-thrombotic disorders.
To determine whether endogenous sex hormones (estradiol (E2), testosterone (T), sex hormone binding globulin (SHBG), and follicle-stimulating hormone (FSH)) are longitudinally associated with progression of atherosclerosis among women at midlife.
249 Pre- or early peri-menopausal women (42–57 years) from the Study of Women’s Health Across the Nation (SWAN) were followed for up to 9 years (median=3.7 years) and had up to 5 repeated measures of common carotid intima-media thickness (IMT) and adventitial diameter (AD). Linear mixed models were used for statistical analysis. Final models included age at baseline, time since baseline, cycle day of blood draw, race, income, SBP, BMI, insulin resistance index, lipids, C-reactive protein and co-morbidity.
In final models for IMT, each one log unit decrease in SHBG was associated with a 0.005 mm/year increase in IMT progression (P=0.003). E2, T, and FSH were not associated with level or progression of IMT. For AD, each one log unit decrease in E2 was associated with a 0.012 mm/year increase in AD progression (P=0.04) and each one log unit increase in FSH was associated with a 0.016 mm/year increase in AD progression (P=0.003). T and SHBG were not associated with progression or level of AD.
Independent of SBP, BMI, lipids and other covariates, lower E2 and SHBG, and higher FSH were associated with increased subclinical atherosclerosis progression in women at midlife.
subclinical atherosclerosis; sex hormones; women
Misfolded immunoglobulin light chain proteins (LC) in light chain amyloidosis (AL) are toxic to vascular tissues. We tested the hypothesis that chaperone protein clusterin preserves endothelial function and cell survival during LC exposure.
LC (20 μg/mL) were given to human aortic endothelial cells (EC) for 24-hours and clusterin protein/gene expression and secretion were measured. DNA fragmentation was measured with/without recombinant clusterin (Clu, 300 ng/mL). Adipose arterioles (non-AL subjects) were tested for dilator responses to acetylcholine/papaverine at baseline and after 1-hour of LC±Clu.
LC reduced EC clusterin secretion, protein and gene expression while increasing DNA fragmentation. Clu attenuated LC-induced DNA fragmentation and restored dilator response to acetylcholine (logEC50: control −7.05±0.2, LC+Clu −6.53±0.4, LC −4.28±0.7, p<0.05 vs. control, LC+Clu).
LC induced endothelial cell death and dysfunction while reducing clusterin protein/gene expression and secretion. Exogenous clusterin attenuated LC toxicity. This represents a new pathobiologic mechanism and therapeutic target for AL amyloidosis.
amyloid; endothelial function; chaperone protein
Hydrogen sulfide (H2S) is an important signaling molecule whose blood levels have been shown to be lower in certain disease states. Increasing evidence indicates that H2S plays a potentially significant role in many biological processes and that malfunctioning of H2S homeostasis may contribute to the pathogenesis of vascular inflammation and atherosclerosis. This study examined the fasting blood levels of H2S, HDL-cholesterol, LDL-cholesterol, triglycerides, adiponectin, resistin, and potassium in 36 healthy adult volunteers. There was a significant positive correlation between blood levels of H2S and HDL-cholesterol (r=0.49, p=0.003), adiponectin (r=0.36, p=0.04), and potassium (r=0.34, p=0.047), as well as a significant negative correlation with LDL/HDL levels (r= -0.39, p=0.02). This is the first demonstration of an association of circulating levels of H2S with the HDL, LDL, and adiponectin homeostasis in the blood of healthy humans.
H2S; lipids; adiponectin
Rho-associated kinases (ROCKs) have been shown to be involved in the pathogenesis of atherosclerosis. It is clinically important to estimate the degree of ROCK activity in humans. The purpose of this study was to confirm the validity of a leukocyte ROCK parameter as an index of ROCK activity in comparison with vascular response to a ROCK inhibitor.
Methods and Results
We evaluated the ratio of phospho myosin-binding subunit (p-MBS) on myosin light-chain phosphatase to total MBS in peripheral leukocytes by Western blot analysis and forearm blood flow (FBF) response to the ROCK inhibitor fasudil using strain-gauge plethysmography in 36 healthy subjects and 39 patients with cardiovascular diseases. Fasudil (3, 10, 30 μg/min) was infused intra-arterially for 5 minutes at each dose. Leukocyte p-MBS/total-MBS was higher in cardiovascular diseases than in healthy subjects (0.97±0.37 vs. 0.51±0.14; P=0.002). Fasudil increased FBF from 4.9±1.2 to 14.5±5.7 mL/min/100 mL tissue (P<0.0001) in patients with cardiovascular diseases, while fasudil did not alter FBF in healthy subjects. There was a significant relationship between leukocyte p-MBS/total-MBS and maximal FBF response to fasudil in all subjects (r=0.72, P<0.0001). There was also a significant correlation between p-MBS/total-MBS and maximal FBF response to fasudil in patients with cardiovascular diseases (r=0.59, P<0.0001). In healthy subjects, there was no significant correlation between the two parameters.
These findings suggest that assessment of leukocyte ROCK activity is minimally invasive and does not require pharmacologic intervention using ROCK inhibitors. Leukocyte p-MBS/total-MBS may be useful for evaluating ROCK activity in a clinical setting.
High serum uric acid levels are associated with gout, atherosclerosis and cardiovascular disease. Three genes (SLC2A9, ABCG2, and SLC17A3) were reported to be involved in the regulation of uric acid levels.
Design and Methods: SNPs rs2231142 (ABCG2) and rs1165205 (SLC17A3) were genotyped in three cohorts (n = 4492) and combined with previously genotyped SNPs within SLC2A9 (rs6855911, rs7442295, rs6449213, rs12510549).
Each copy of the minor allele decreased uric acid levels by 0.30–0.38 mg/dL for SLC2A9 (p values: 10−20–10−36) and increased levels by 0.34 mg/dL for ABCG2 (p = 1.1×10−16). SLC17A3 influenced uric acid levels only modestly. Together the SNPs showed graded associations with uric acid levels of 0.111 mg/dL per risk allele (p = 3.8×10−42). In addition, we observed a sex-specific interaction of age with the association of SLC2A9 SNPs with uric acid levels, where increasing age strengthened the association of SNPs in women and decreased the association in men.
Genetic variants within SLC2A9, ABCG2 and SLC17A3 show highly significant associations with uric acid levels, and for SNPs within SLC2A9 this association is strongly modified by age and sex.
Epidemiology; Genetics; Uric acid; Copy number variation; Sex-specific effect; Genetic risk score
ABCA1; SR-BI; Atherosclerosis; Cholesterol Efflux; High Density Lipoproteins
The apolipoprotein E mimetic peptide Ac-hE18A-NH2, capable of reducing plasma cholesterol and possessing anti-inflammatory properties, was compared with the well-studied anti-atherogenic apoA-I mimetic peptide 4F for reducing lesion formation in female apoE null mice with already existing lesions.
Methods and Results
In initial experiments, Ac-hE18A-NH2 was administered retro-orbitally two or three times weekly for 6 to 8 weeks, while peptide 4F was administered intraperitoneally every day for the same period. Age matched controls were injected with saline every day. At the end of the treatment period, plasma cholesterol levels of Ac-hE18A-NH2 administered mice were significantly lower than in 4F and control mice. However, both 4F and Ac-hE18A-NH2 showed reduced lesion areas in en face lesion analysis to a similar extent compared to the control group, while paraoxonase-1 (PON-1) activity was increased only in the Ac-hE18A-NH2 group. In the third experiment, both peptides were administered at the same dose, frequency, and route of administration. The reduction in en face lesions with Ac-hE18A-NH2 was significantly greater than the 4F and control groups, although lesions in 4F-treated mice were also significantly reduced compared with controls. Both peptide groups had significantly reduced plasma lipid hydroperoxides, but only the Ac-hE18A-NH2 group had significantly reduced serum amyloid A levels. HDL and plasma inflammatory indices were significantly reduced in both peptide groups compared with controls.
Although both peptides had similar anti-inflammatory properties, Ac-hE18A-NH2 was more effective in inhibiting lesions than 4F at the same dose, frequency, and route of administration, perhaps due to its cholesterol reducing properties.
Atherosclerosis; cholesterol; peptides; oxidation; inflammation
Both fatty liver and abdominal visceral fat (VAT) are associated with cardiometabolic risk factors. Whether fatty liver and VAT are jointly associated with coronary artery (CAC) or abdominal aortic (AAC) calcification is not clear.
Jackson Heart Study (JHS) participants (n=2884, mean age 60 years, 65% women) underwent non-contrast CT Exam for assessment of fatty liver, VAT, and CAC and AAC. Fatty liver was measured by liver attenuation (LA; low LA=high fatty liver). The Agatston score was used to quantify the amount of calcified artery plaque and the presence of calcified artery plaque was defined as Agatston score>0. Cross-sectional associations of LA and VAT with CAC and AAC were examined in logistic regression models.
LA (per 1-standard deviation [SD] decrement) was associated inversely with CAC in age-sex-adjusted (OR 0.84, 95%CI 0.7–0.9, p=0.0001) and multivariable adjusted models (OR 0.89, 95%CI 0.8–0.9, p=0.01). The association persisted for LA with CAC when additionally adjusted for body mass index (BMI) (OR 0.89, 95%CI 0.8–0.9, p=0.03) or VAT (OR 0.90, 95%CI 0.8–0.9, p=0.04). Abdominal VAT (per 1-SD increment) was positively associated with CAC in age-sex-adjusted models (OR 1.27, 95%CI 1.2–1.4, p=0.0001), but the association was diminished with multivariable adjustment (OR 1.10, 95%CI 0.9–1.2, p=0.09) and with additional adjustment for LA (p = 0.24) or BMI (p = 0.33). For AAC, the associations with LA and VAT were only present in age-sex-adjusted models. Finally, we did not observe interactions between LA and VAT for CAC (p=0.18) or AAC (p=0.24).
Fatty liver is associated with coronary atherosclerotic calcification independent of abdominal VAT or BMI in African Americans. Further investigations to uncover the clinical implications of fatty liver on coronary atherosclerosis in obesity are warranted.
To determine whether the 9p21 SNP association with coronary heart disease is modified by other classical or novel risk markers.
The 9p21 SNP (rs10757274) and multiple risk markers were measured in the Atherosclerosis Risk in Communities Study, and incident coronary disease events were ascertained. Effect modification (interaction) of the 9p21 SNP with risk markers was tested in Cox proportional hazard regression models.
The incidence rates of coronary heart disease per 1000 person-years were 14.4, 17.0, and 18.7 for AA, AG, and GG genotypes, yielding hazard ratios of 1.0, 1.20 (95% CI = 1.07-1.36), and 1.34 (95% CI = 1.16-1.53). There was no meaningful evidence of an interaction (all p-interaction > 0.04) between 9p21 SNP and any of 14 other risk markers for coronary heart disease. These included novel markers not previously explored for 9p21 interaction (e.g., cardiac troponin T and N-terminal pro-brain natriuretic peptide).
Our study extends evidence that the 9p21 SNP association with coronary heart disease is not modified by classical or novel risk markers. Our findings therefore rule out additional plausible pathways by which 9p21 might have increased coronary heart disease risk.
coronary disease; prospective study; 9p21 SNP
The objective of this study is to develop a method for selective detection of the calcific (hydroxyapatite) component in human aortic smooth muscle cells in vitro and in calcified cardiovascular tissues ex vivo. This method uses a novel optical molecular imaging contrast dye, Cy-HABP-19, to target calcified cells and tissues.
A peptide that mimics the binding affinity of osteocalcin was used to label hydroxyapatite in vitro and ex vivo. Morphological changes in vascular smooth muscle cells were evaluated at an early stage of the mineralization process induced by extrinsic stimuli, osteogenic factors and a magnetic suspension cell culture. Hydroxyapatite components were detected in monolayers of these cells in the presence of osteogenic factors and a magnetic suspension environment.
Atherosclerotic plaque contains multiple components including lipidic, fibrotic, thrombotic, and calcific materials. Using optical imaging and the Cy-HABP-19 molecular imaging probe, we demonstrated that hydroxyapatite components could be selectively distinguished from various calcium salts in human aortic smooth muscle cells in vitro and in calcified cardiovascular tissues, carotid endarterectomy samples and aortic valves, ex vivo.
Hydroxyapatite deposits in cardiovascular tissues were selectively detected in the early stage of the calcification process using our Cy-HABP-19 probe. This new probe makes it possible to study the earliest events associated with vascular hydroxyapatite deposition at the cellular and molecular levels. This target-selective molecular imaging probe approach holds high potential for revealing early pathophysiological changes, leading to progression, regression, or stabilization of cardiovascular diseases.
atherosclerosis; calcification; hydroxyapatite; molecular imaging; osteocalcin
Carotid atherosclerosis has been suggested to be involved in cognitive decline.
The Epidemiology of Hearing Loss Study is a longitudinal study of aging among Beaver Dam residents, WI. In 1998–2000, carotid intima-media thickness (IMT) and plaque were measured by ultrasound; cognitive function was measured by the Mini-Mental State Examination (MMSE). Follow-up examinations were conducted in 2003–2005 and 2009–2010. Incidence of cognitive impairment was defined as a MMSE score <24 or reported physician-diagnosed dementia during the follow-up. In the last examination, five additional cognitive tests were added. The associations of carotid atherosclerosis with incident cognitive impairment and cognitive test performance ten years later were evaluated.
A total of 1651 participants (mean age 66.8 years, 41% men) without cognitive impairment at baseline were included in the incidence analysis. IMT was associated with incidence of cognitive impairment after multiple adjustments (hazard ratio: 1.09, p=0.02 for each 0.1 mm increase in IMT). A total of 1311 participants with atherosclerosis data at baseline had the additional cognitive tests 10 years later. Larger IMT was associated with longer time to complete the Trail-Making Test-part B after multiple adjustments (0.1 mm IMT: 2.3 seconds longer, p=0.02). Plaque was not associated with incident cognitive impairment or cognitive test performance 10 years later.
In this population-based longitudinal study, carotid IMT was associated with a higher risk of developing cognitive impairment during the 10-year follow-up, and was associated with poorer performance in a test of executive function 10 years later.
Carotid atherosclerosis; cognitive impairment; longitudinal; population-based; epidemiology
To investigate the effect of an exercise intervention on flow-mediated dilation (FMD) and circulating endothelial biomarkers in adults with type 2 diabetes (T2DM)
Sedentary adults (n=140), aged 40–65, with T2DM and untreated pre- or Stage I hypertension or treated hypertension were randomized to a 6-month, supervised, exercise program (3×week) or a sedentary control. Assessments included BMI, body and visceral fat, blood pressure, lipids, HbA1c, insulin sensitivity (QUICKI), fitness, FMD, E-selectin, P-selectin, intracellular and vascular cellular adhesion molecules (ICAM, VCAM), and tissue plasminogen activator (tPA). Intervention effects were compared by t-tests. Pearson’s correlations were calculated between changes in cardiovascular risk factors and endothelial outcomes.
Exercisers significantly improved BMI (−0.6 kg/m2), body fat % (−1.4%), HbA1c (−0.5%), and fitness (2.9 mL/kg·min) vs. controls (p<0.05). However, there were no differences between groups in changes in FMD, E-selectin, P-selectin, ICAM, VCAM, or tPA. Among exercisers, changes in cardiovascular risk factors correlated with several biomarkers. Decreased P-selectin correlated with decreased BMI (r=0.29, p=0.04) and increased HDL cholesterol (r=−0.36, p=0.01). Decreased ICAM correlated with decreased triglycerides and HbA1c (r=0.30, p=0.04; r=0.31, p=0.03) and increased QUICKI (r=−0.28, p=0.05). Decreased tPA correlated with decreased total body and visceral fat (r=0.28, p=0.05; r=0.38, p=0.008) and increased QUICKI (r=−0.38, p=0.007).
While exercise resulted in improved fitness, body composition, and glycemic control, there were no changes in FMD or circulating endothelial biomarkers. The associations of changes in cardiovascular risk factors and endothelial biomarkers suggest that improvement in risk factors could mediate the exercise-induced improvements in endothelial function seen in prior studies.
Endothelial function; adhesion molecules; exercise; type 2 diabetes; vasodilation
E-selectin-1 (ESL-1), also known as golgi complex-localized glycoprotein-1 (GLG1), homocysteine-rich fibroblast growth factor receptor (CGR-1), and latent transforming growth factor-β complex protein 1 (LTCP-1), is a multifunctional protein with widespread tissue distribution. To determine the functional consequences of ESL-1 deficiency, mice were generated carrying an ESL-1 gene trap. After backcrossing to C57BL6/J for 6 generations, mice heterozygous for the gene trap (ESL-1+/-) were intercrossed to produce ESL-1-/- mice, however ESL-1-/- mice were not viable, even at embryonic day E10.5. To determine the effect of heterozygous ESL-1 deficiency on atherosclerosis, apolipoprotein E deficient (ApoE-/-), ESL-1+/- mice were generated and fed western diet. Compared to ApoE-/-, ESL-1++ mice, atherosclerotic lesions from ApoE-/-, ESL-1+/- contained more collagen and fewer macrophages, suggesting increased plaque stability. In conclusion, heterozygous deficiency of ESL-1 is associated with features of increased atherosclerotic plaque stability while complete deficiency of ESL-1 leads to embryonic lethality.
leukocyte; selectins; macrophage; atherosclerosis; endothelium
Isolated diastolic dysfunction is present in 40% of heart failure patients. It has been attributed to myocardial fibrosis and related to cardiovascular risk factor exposure. We hypothesized that simvastatin will improve these dynamics in experimental hypercholesterolemia (HC).
Three groups of pigs were studied after 12 weeks of normal (N) diet, HC diet, or HC diet with simvastatin (80 mg/day) treatment. Cardiac function was assessed by electron beam computed tomography (EBCT) and percentage of myocardium occupied by microvessels (myocardial vascular fraction) was calculated by micro-CT. Collagen content was determined by Sirius red staining and confirmed by a quantitative, hydroxyoproline-based assay.
Compared with N, LDL serum concentration was higher in HC and HC + simvastatin (1.0 ± 0.1 vs. 7.9 ± 1.7 and 9.6 ± 1.2 mmol/L, p < 0.05 for both). Cardiac early diastolic filling was reduced in HC compared with N (102.4 ± 11.3 vs. 151.1 ± 12.1 mL/s; p < 0.05) but restored in HC + simvastatin (176.8 ± 21.3 mL/s, p < 0.05 vs. HC). Compared with N, myocardial vascular fraction was higher in HC but not in HC + simvastatin (1.98 ± 0.84 vs. 4.48 ± 0.31 and 2.95 ± 0.95%; p < 0.05 for HC vs. N). Myocardial collagen content was higher in HC than in HC + simvastatin and N (4.72 ± 1.03 vs. 1.62 ± 0.12 and 1.21 ± 0.24% area staining; p < 0.05 for HC vs. N), which was attributable mainly to an increase in collagen III (2.90 ± 0.48 vs. 1.62 ± 0.12 and 1.21 ± 0.24% area staining; p < 0.05 for HC vs. N).
Simvastatin is able to prevent diastolic dysfunction in experimental HC independent of its lipid lowering effect. This beneficial effect is, at least partially, due to a decrease in myocardial fibrosis and angiogenesis.
Diastolic dysfunction; Hypercholesterolemia; Fibrosis; Angiogenesis
To assess the relationship of lipoprotein subfractions to coronary heart disease (CHD).
Prospective 29.1 year follow-up of 1905 men measured for lipoprotein mass concentrations by analytic ultracentrifugation between 1954 and 1957. Vital status was determined for 97.2% of the cohort. Blinded physician medical record and death certificate review confirmed 179 CHD deaths. Follow-up questionnaires identified 182 nonfatal myocardial infarctions and 93 revascularization procedures from 1,346 (98.3%) of the surviving cohort and from the next-of-kin of 153 men who died.
When adjusted for age, total incident CHD was inversely related to HDL2-mass (P=0.0001) and HDL3-mass (P=0.02), and concordantly related to LDL-mass (P<10−11), IDL-mass (P<10−7), and small (P<10−7) and large VLDL-mass concentrations (P=0.003). The hazard reduction per mg/dl of HDL was greater for HDL2-mass than HDL3-mass (P=0.04). The lowest quartiles of both HDL2-mass (P=0.007) and HDL3-mass (P=0.001) independently predicted total incident CHD when adjusted for traditional risk factors. Risk for premature CHD (≤ 65 years old) was significantly greater in men within the lowest HDL2 (P=0.03) and HDL3 quartiles (P=0.04) and having higher LDL-mass concentrations (P=0.001). Serum cholesterol’s relationship to incident CHD (P<10−8) was accounted for by adjustment for LDL-mass concentrations (adjusted P=0.90).
Lipoprotein subfractions differ in their relationship to CHD.
Lipoprotein; high-density lipoproteins; risk factors; prevention
Hypercholesterolemia is associated with decreased vascular nitric oxide bioavailability and deletion of endothelial nitric oxide synthase (eNOS) markedly accelerates atherosclerosis development in apolipoprotein E knockout (apoE ko) mice. The current study tests whether atheroprotection provided by a lipid lowering therapy with Ezetimibe depends on eNOS.
ApoE ko and apoE/eNOS double ko (dko) mice received a high fat diet with or without 0.05% Ezetimibe. Ezetimibe significantly reduced plasma cholesterol concentrations and atherogenic lipoproteins in both genotypes to a similar extent. Moreover, the drug reduced vascular inflammation, as it significantly reduced Vascular Cell Adhesion Molecule-1 (VCAM-1) expression and vascular CD14 expression, a marker for mononuclear cell infiltration, in both genotypes. Neither NOS protein expression nor vascular reactivity of aortic rings were changed in apoE ko mice following Ezetimibe treatment. Significant lesion reduction was seen in Ezetimibe treated male and female apoE ko and apoE/eNOS dko animals (p≤0.05). Interestingly, the drug mediated additional atheroprotection in male apoE ko, compared to male eNOS dko mice, suggesting that lipid lowering does provide additional eNOS dependent atheroprotection in this experimental group.
Lipid lowering with Ezetimibe potently reduces atherosclerosis and vascular inflammation independent of eNOS. Moreover, Ezetimibe did not exert any effects on eNOS protein expression or enzyme activity. However, additional atheroprotection by Ezetimibe was observed in eNOS competent apoE ko mice, suggesting that some of the drug's antiatherosclerotic effects are mediated by the eNOS pathway.
Fenofibrate therapy reduces serum triglycerides (TG) and increases high-density lipoprotein-cholesterol (HDL-C) and thus addresses the atherogenic dyslipidemia associated with metabolic syndrome (MetS). Our hypothesis is that genetic factors contribute to the variability of lipid response to fenofibrate differently in subjects with MetS and without MetS.
We investigated the association in 25 candidate genes with lipid responses to a 3-weeks trial on fenofibrate in subjects with and without MetS. We employed growth curve mixed models to generate the response phenotypes to fenofibrate in TG, HDL-C, and low-density lipoprotein-cholesterol (LDL-C) and examined the genetic associations accounting for family dependencies.
After correcting for multiple testing (p<0.05) and accounting for significant differences in the association effect sizes between subjects with and without MetS (p<0.05), variants of APOA5 (rs662799) and APOE (rs429358) were associated with HDL-C and LDL-C responses in MetS subjects, while APOA4 (rs675)was associated with TG response in non-MetS subjects. There was also suggestive evidence that MetS may interact with APOA4 (p=0.017), APOA5 (p=0.06), and APOE (p=0.09) to the variation to lipid responses.
Genetic effects that contributed to the variability of lipid responses to fenofibrate may differ in subjects with and without MetS. This research may provide guidance for more personalized and effective therapies.
One-half of Americans currently meet guideline physical activity levels. For these individuals, exceeding guideline levels may provide additional health benefits.
Incident physician-diagnosed myocardial infarction and angina, revascularization procedures (CABG, PTCA), and ischemic heart disease deaths during 7.7-year follow-up were compared to baseline usual distance run in 35,402 male runners.
Men reported 467 incident CHD and the National Death Index identified an additional 54 ischemic heart disease deaths. Per km/day run, the men’s risks declined 5% for fatal and nonfatal CHD (P = 0.001), nonfatal CHD (P = 0.0008), and revascularization procedures (P = 0.002). Their risks for nonfatal myocardial infarctions and angina declined 7% (P = 0.02) and 10% (P = 0.003), respectively. Compared to <3 km/day run (upper limit guideline level), >9 km/day run produced risks 65% lower for angina (P = 0.008), 29% lower for nonfatal CHD (P = 0.04), and 26% lower for fatal and nonfatal CHD (P = 0.06).
Exceeding guideline physical activity levels produce important CHD-risk reductions.
Epidemiology; physical activity; prevention; cardiovascular disease