bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Monocytes/Macrophages Release TNF-α in Response to Ox-LDL
Authors: Jovinge Stefan , Ares Mikko P.S. , Kallin Bengt , Nilsson Jan
Published: June 2011

The uptake of oxidatively modified low density lipoprotein (Ox-LDL) by intimal macrophages is believed to play a key role in the development of atherosclerosis. The present study demonstrates that Ox-LDL in low concentrations activates monocyte/macrophage release of factors that stimulate smooth muscle cell growth, whereas higher concentrations are inhibitory. Exposure of monocytes/macrophages to 8 μg/mL Ox-LDL increased expression of tumor necrosis factor-α (TNF-α) mRNA but had no effect on interleukin-1β, platelet-derived growth factor B and heparin-binding epidermal growth factor–like mitogen mRNA levels. Ox-LDL also stimulated monocyte/macrophage release of TNF-α in a dose-dependent manner, with maximal effect at an LDL concentration of 8 μg/mL. Addition of TNF-α–blocking antibodies to conditioned medium from monocytes/macrophages already exposed to Ox-LDL reduced mitogenic activity by 44.7±8.4% (P<.005). Stimulation of TNF-α release by Ox-LDL was associated with activation of transcription factor AP-1, whereas the activity of transcription factor nuclear factor-κB remained unchanged. These findings suggest that enhanced secretion of TNF-α by macrophages exposed to Ox-LDL may be involved in the formation of atherosclerotic lesions.
Plasma Fibrinogen and Coronary Heart Disease in Elderly Japanese-American Men
Authors: Sharp Dan S. , Abbott Robert D. , Burchfiel Cecil M. , Rodriguez Beatriz L. , Tracy Russell P. , Yano Katsuhiko , Curb J. David
Published: June 2011

Abstract
Clinical and epidemiological studies consistently indicate that elevations in plasma fibrinogen concentration are associated with the presence and development of coronary heart disease (CHD). These elevations are strongly correlated with smoking behavior and may play a significant role in mediating a relation of smoking to CHD. This cross-sectional survey of 3571 elderly Japanese-American men, aged 71 through 93 years, represents survivors of the Honolulu Heart Program cohort. Active smokers are almost twice as likely to be represented in the highest quintile of the fibrinogen distribution compared with the lowest quintile (9.8% versus 5.3%, respectively). The highest prevalence of CHD (34%) was noted in past and current smokers who were in the highest quintile of fibrinogen. The age-adjusted relative odds of prevalent CHD comparing the average fibrinogen levels in the first and fifth quintiles were 1.36 (95% confidence interval, 1.13 to 1.64). After adjustment for smoking status, blood pressure, total and HDL cholesterol, diabetes status, hematocrit, and white cell count, the association between fibrinogen and CHD was changed slightly and remained statistically significant (
P
<.05). These findings in an elderly cohort of Japanese-American men are consistent with previous studies among middle-aged adults demonstrating fibrinogen to be associated with indicators of clinical CHD and CHD risk factors. Because of the cross-sectional nature of this study, it is not possible to distinguish whether the observed relation of fibrinogen to prevalent CHD is causal or whether it represents a marker of active and progressive disease.
Effect of Age on the Pattern of Short-term Albumin Uptake by the Rabbit Aortic Wall Near Intercostal Branch Ostia
Authors: Sebkhi Abdelkrim , Weinberg Peter D.
Published: June 2011

Abstract
Lipid deposition occurs more frequently downstream than upstream of branches in immature human aorta but the opposite pattern is seen in mature vessels. These distributions may reflect variation in the uptake of plasma macromolecules by the aortic wall. We have recently shown that the quasi–steady state uptake of albumin is greater downstream than upstream of branches in immature rabbit aortas and that the opposite pattern occurs in mature animals. Additionally, there is a sharp drop in the mean uptake shortly after weaning. In the present study, the mechanisms underlying these phenomena were investigated by examining the short-term uptake of albumin and its distribution across the wall. Albumin was labeled with a fluorescent dye and introduced into the circulation of conscious New Zealand White rabbits. Thoracic aortas were fixed in situ 10 minutes later and were sectioned through the center of intercostal ostia. Fluorescence from sections was measured by using digital imaging fluorescence microscopy and was converted to tracer concentrations after appropriate autofluorescence levels had been subtracted. In animals aged 45 days, more tracer was detected in the wall downstream than upstream of branches; the difference between regions was >100% of the mean value. This percentage halved and the mean uptake decreased almost threefold by 75 days. In mature animals, the mean value remained at the 75-day level but the converse distribution was seen; 22% more tracer was detected upstream than downstream. These trends were insensitive to the depth of the intimal-medial layer examined. In each region, the maximum tracer concentration occurred close to the luminal surface but not always within the first 2.9-μm-thick layer of the wall. Maxima were similar in magnitude to those observed at quasi–steady state, but the fall with increasing distance into the wall was much sharper. In many cases concentrations remained constant over most of the media, and rises toward the adventitial boundary were rarely seen. Uptake after 10 minutes predominantly reflects the rate at which tracer enters the wall. The concentration profiles were consistent with most of the tracer having entered from the luminal surface and with the involvement of convective transport. The trends observed with age closely paralleled those occurring at quasi–steady state. Consequently, the latter are also likely to be determined by changes in the resistance of the wall to macromolecule influx.
Increased Expression of Genes for Platelet-Derived Growth Factor in Circulating Mononuclear Cells of Hypercholesterolemic Patients
Authors: Billett Michael A. , Adbeish Idris S. , Alrokayan Salman A.H. , Bennett Andrew J. , Marenah Christine B. , White David A.
Published: June 2011

Abstract
Platelet-derived growth factor (PDGF) is implicated in the accumulation of smooth muscle cells in atherosclerotic lesions following monocyte migration through the vascular endothelium. We show here a 15- to 20-fold increase in expression of PDGF-A and -B genes (as measured by a quantitative reverse transcription–polymerase chain reaction assay of mRNA concentration) in circulating monocytes of hypercholesterolemic and hyperlipidemic patients compared with normocholesterolemic individuals. Strong positive correlations between PDGF-A and -B mRNA concentrations indicate that the two genes are coordinately regulated in mononuclear cells in both normal and hypercholesterolemic individuals. PDGF gene expression in patients correlates with concentrations of plasma total cholesterol and of low-density lipoprotein cholesterol, a proven risk factor for atherosclerosis. Activation of monocyte PDGF expression may be an important component of the atherosclerotic risk associated with raised cholesterol levels and may represent an essential step in the early stages of atherogenesis. However, the marked increases in PDGF mRNA levels in patients with modest hypercholesterolemia compared with normal subjects suggest that other factors are involved. The relationship of monocyte PDGF expression to other atherosclerotic risk factors and to the different stages of atherosclerosis needs to be carefully evaluated.
Multiple Risk Intervention in High-Risk Hypertensive Patients
Authors: Suurküla Madis , Agewall Stefan , Fagerberg Björn , Wendelhag Inger , Wikstrand John
Published: June 2011

Abstract
In spite of optimal blood pressure control, available data indicate that the risk of coronary heart disease remains high in many patients with hypertension. Multifactorial risk intervention programs have therefore been advocated. The aim of the present randomized study was to analyze whether a favorable change in risk factors caused by a comprehensive risk factor modification program (focused mainly on nonpharmacological intervention) might beneficially affect ultrasound-assessed far-wall common carotid intima-media thickness or plaques in the carotid artery in high-risk hypertensive patients (n=81) in comparison with those undergoing usual care (n=83). A further aim was to analyze whether risk factors measured at baseline or follow-up were related to the change recorded in intima-media thickness during follow-up. The results showed in the intervention group a favorable change in LDL cholesterol (−9%), in smoking habits (32% of smokers quit smoking), and in HbA
1c
(−17% in patients with diabetes mellitus) over the 3.5-year observation period. However, no difference between the two randomization groups could be observed for far-wall common carotid intima-media thickness or plaque status during follow-up. Of all tested potential risk factors, only fasting insulin at baseline (available in nondiabetic patients) was significantly related to the change in mean intima-media thickness during follow-up (
r
=.25, n=92,
P
<.01). The relationship (negative) between follow-up serum HDL and change in mean intima-media thickness during the preceding follow-up was of borderline significance. Patients with moderate to large plaques in the carotid artery region at baseline had a significantly larger increase in common carotid artery intima-media thickness during follow-up than patients with no or only small plaques. The results are disappointing and may indicate that either the change in risk factors occurred too late in life or a considerably larger change in concomitant risk factors than we observed is needed to favorably affect intima-media thickness during an observation period of around 3 years in high-risk hypertensive patients.
Race and Gender Differences in the Association of Lp(a) With Carotid Artery Wall Thickness
Authors: Schreiner Pamela J. , Heiss Gerardo , Tyroler H.A. , Morrisett Joel D. , Davis C.E. , Smith Robert
Published: June 2011

Abstract
The association of lipoprotein(a) [Lp(a)] with preclinical atherosclerotic disease is not well established in any race group, particularly African Americans. This report examined the association of Lp(a) with preclinical extracranial carotid atherosclerosis in middle-aged black and white participants in the Atherosclerosis Risk in Communities (ARIC) Study. Study participants (15 124: 2417 black women, 1522 black men, 5907 white women, and 5278 white men) who were 45 to 64 years old at baseline were examined during the period 1987 to 1989. Carotid intimal-medial far-wall thickness was determined by B-mode ultrasonography and expressed as the overall wall thickness mean at six sites to approximate atherosclerosis in the carotid system. Lp(a) was measured as its total protein component, Lp(a) protein, by a double-antibody ELISA for apolipoprotein(a) detection. Mean Lp(a) protein levels were higher in blacks than whites (169.1 and 147.0 μg/mL in black women and black men, respectively, compared with 86.6 and 75.1 μg/mL in white women and white men). Mean carotid wall thickness (in millimeters) varied by race and gender: 0.798 in white men, 0.779 in black men, 0.718 in black women, and 0.695 in white women. Multivariable-adjusted Lp(a) protein was independently associated with wall thickness (in millimeters) in white men and black men; among women, however, this association appeared to be stronger when smoking and diabetes were present. A 100-μg/mL difference in Lp(a) protein level was associated with 0.049- and 0.043-mm higher wall thickness values in black men and white men, respectively. Among white women who smoked, the difference in wall thickness was 0.051 mm compared with 0.032 mm for former/never smokers and 0.21 mm in black female diabetics compared with 0.031 mm in black female nondiabetics. These results suggest that Lp(a) is associated with preclinical carotid atherosclerosis in both blacks and whites, but that this association may be affected by the presence of other cardiovascular risk factors, particularly in women.
Role of Intimal Hyperplasia and Arterial Remodeling After Balloon Angioplasty
Authors: Guzman Luis A. , Mick Mathew J. , Arnold Anita M. , Forudi Farhad , Whitlow Patrick L.
Published: June 2011

Abstract
The arterial response to injury appears to be an important factor in the development of restenosis. Traditionally, intimal hyperplasia has been thought to be the primary mechanism responsible for restenosis. However, recent studies have found that arterial remodeling is a major determinant of lumen loss after balloon angioplasty. In this study, we evaluated the actual separate contributions of intimal hyperplasia and arterial remodeling to the restenotic process after balloon angioplasty in the atherosclerotic rabbit model. One month after induction of focal atherosclerotic lesions, femoral arteries were randomized to receive treatment with either two or six balloon inflations. One group of rabbits was euthanized immediately after angioplasty to evaluate the initial degree of injury with each dilatation strategy (“acute group”), and the rest were euthanized 28 days after angioplasty (“chronic group”). Arteries that had been treated with six inflations had a higher injury score than those treated with two (4.0±3.0 versus 1.9±1.5,
P
<.05). In the chronic group, there was a significant increase in intimal area in the six inflation–treated arteries compared with the two-inflation group (0.617±0.06 versus 0.432±0.05 mm
2
,
P
<.004). However, there was no significant difference in lumen cross-sectional area between groups. By multivariate analysis, the most important independent predictor of lumen area was the external elastic lamina (EEL) area, although the degree of intimal thickening was also a significant independent predictor. There was a strong, positive correlation between intimal area and EEL area: the larger the intimal area, the larger the EEL area (
r
=.703,
P
<.0001). The intimal area was similar in both restenotic and nonrestenotic lesions. In contrast, EEL area was significantly larger (due to remodeling) in nonrestenotic lesions. This study confirms previous findings that the degree of injury determines the degree of neointimal proliferation and supports recent findings that chronic arterial remodeling plays a major role in the final lumen area. Understanding and controlling the remodeling process rather than concentrating solely on intimal hyperplasia may yield better results after balloon angioplasty in the future.
White Blood Cell Count and the Risk of Coronary Heart Disease and All-Cause Mortality in Elderly Men
Authors: Weijenberg M.P. , Feskens E.J.M. , Kromhout D.
Published: June 2011

Abstract
Because the importance of established risk factors for coronary heart disease (CHD) is unclear in older people, the associations of white blood cell (WBC) count with the risk for CHD and all-cause mortality were investigated in an elderly cohort that was followed up for 5 years. In 1985, complete information on the risk factors of interest was available for 884 randomly selected men, aged 64 to 84 years, from the Dutch town of Zutphen (participation rate, 74%). Relative risks (RRs) for each 10
9
/L increase in WBC count were obtained for the 5-year incidence of and mortality from CHD and all causes. RRs were adjusted for age, body mass index, systolic blood pressure, total and high density lipoprotein cholesterol levels, and cigarette smoking habit. The WBC count was 6.7±1.8×10
9
/L (mean±SD) at baseline. An increased WBC count was independently associated with mortality due to CHD, and the RR amounted to 1.32 (95% confidence interval [95% CI], 1.15 to 1.51). For the incidence of CHD the RR was 1.14 (95% CI, 0.98 to 1.32). These associations were observed regardless of cigarette smoking habit. Regarding all-cause mortality, the RR amounted to 1.25 (95% CI, 1.17 to 1.35). This association was especially noticeable among former smokers and those who had never smoked. In conclusion, during 5 years of follow-up WBC count predicted CHD and all-cause mortality in elderly men, independent of the conventional risk factors for CHD.
Evidence That Implicates the Parathyroid Hormone–Related Peptide in Vascular Stenosis
Authors: Ozeki Shin-ichiro , Ohtsuru Akira , Seto Shinji , Takeshita Satoshi , Yano Hiroki , Nakayama Toshiyuki , Ito Masahiro , Yokota Tadaaki , Nobuyoshi Masakiyo , Segre Gino V. , Yamashita Shunichi , Yano Katsusuke
Published: June 2011

Abstract
Proliferation of vascular smooth muscle cells (VSMCs) is considered to be one key event underlying the pathophysiology of restenosis after angioplasty. The parathyroid hormone–related peptide (PTHrP) and its receptor, a local autocrine and paracrine regulator of cellular growth in a variety of normal cell types, have been reported in the vicinity of VSMCs. To investigate how PTHrP might be involved in the process of neointimal formation after balloon angioplasty, we examined PTHrP expression in balloon-denuded rat carotid arteries and human coronary arteries that had been retrieved by directional atherectomy. In rat carotid arteries, the RNase protection assay and in situ hybridization demonstrated that PTHrP mRNA expression increased fourfold to sixfold 1 to 7 days after denudation and continued for 28 days, coincident with downregulation of PTH/PTHrP receptor mRNA expression. In situ hybridization and immunohistochemistry revealed that PTHrP expression in balloon-denuded carotid arteries was mainly localized to the neointima. To confirm the involvement of the PTHrP in human coronary artery restenotic lesions, immunohistochemical analysis of human coronary atherectomy specimens (23 primary and 10 restenotic lesions) was then performed. The number of intimal cells that expressed PTHrP protein was significantly higher in restenotic (407±53 cells/mm
2
; range, 143 to 739) than in stable angina (50±12 cells/mm
2
; range, 18 to 132;
P
<.05) or unstable angina (129±16 cells/mm
2
; range, 21 to 232;
P
<.05) specimens. These data demonstrate that PTHrP gene expression in VSMCs markedly increases during neointimal formation, supporting the hypothesis that PTHrP may play an important role in vascular stenosis as a regulator of VSMC proliferation.
Acyl-Coenzyme A:Cholesterol
O
-Acyltransferase Is Not Identical to Liver Microsomal Carboxylesterase
Authors: Diczfalusy Margareta A. , Björkhem Ingemar , Einarsson Kurt , Alexson Stefan E.H.
Published: June 2011

Abstract
Acyl-coenzyme A (CoA):cholesterol
O
-acyltransferase (ACAT) is responsible for esterification of cholesterol in the cell. The enzyme has never been purified, but two cDNA sequences coding for this enzyme were recently reported. One of the sequences was identical to human liver carboxylesterase. We have used inhibitors to elucidate the relation between microsomal carboxylesterase, acyl-CoA hydrolase (ACH), and ACAT activities in rat liver. Low concentrations of serine esterase inhibitors strongly inhibited carboxylesterase and acyl-CoA hydrolase activities but stimulated ACAT activity. At higher concentrations, ACAT activity was also inhibited. A sulfhydryl-modifying agent was found to be a potent inhibitor of ACAT without affecting carboxylesterase activity. Similarly, two specific ACAT inhibitors,
dl
-melinamide and PD 138142-15, inhibited ACAT activity but did not affect carboxylesterase or ACH activities. Our data thus exclude ACAT as a liver microsomal carboxylesterase. The complex inhibition patterns observed with serine esterase inhibitors indicate that carboxylesterases and ACHs may interfere with ACAT activity by competing for the substrate. It is obvious that final identification of ACAT requires demonstration of an active homogenous protein.
Coronary Artery Disease in IDDM
Authors: Lloyd Cathy E. , Kuller Lewis H. , Ellis Demetrius , Becker Dorothy J. , Wing Rena R. , Orchard Trevor J.
Published: June 2011

AbstractInsulin-dependent diabetes mellitus (IDDM) increases the risk of developing coronary artery disease (CAD) compared with that seen in the general population, while the sex differential in rates of CAD is considerably reduced in IDDM populations. To further our understanding of these observations, the effects of gender on baseline risk factors for CAD incidence were examined. Participants in the Pittsburgh Epidemiology of Diabetes Complications (EDC) Study were recruited from the Children’s Hospital of Pittsburgh IDDM registry and had been diagnosed between 1950 and 1980. Subjects completed a series of questionnaires and were given a full clinical examination at baseline (1986 through 1988) and every subsequent 2 years. This report is based on the first 4 years of follow-up. Similar incidence rates of new CAD events were observed in men and women. In neither sex was glycemic control a predictor of later CAD. Sex-specific Cox proportional hazards models showed that for men, duration of IDDM, HDL cholesterol, fibrinogen, hypertension, and smoking were all significantly associated with the onset of CAD. Hypertension, fibrinogen, and smoking were all replaced by nephropathy when this latter variable was added to the model. For women, duration, hypertension, waist-hip ratio, physical activity, and depressive symptomatology were all significant independent predictors of CAD. Nephropathy status did not enter the model for women. While 4-year incidence of CAD in IDDM varies little by sex in this population, the predictive risk factors vary considerably. In particular, the effect of renal disease was stronger in men, while the cluster of physical activity, waist-to-hip ratio, and depressive symptomatology were more important in women. These results may help explain the relatively greater impact IDDM has on CAD risk for women and suggest new potential preventive approaches.
Thrombotic Risk in Hereditary Antithrombin III, Protein C, or Protein S Deficiency
Authors: Pabinger Ingrid , Schneider Barbara
Published: June 2011

Abstract
A cooperative, retrospective study was performed on data from 8 coagulation laboratories and thrombosis units in Austria, Germany, and Switzerland to assess the risk for thrombosis in patients with hereditary antithrombin III (AT-III), protein C (PC), and protein S (PS) deficiencies; to compare the clinical manifestations of these 3 deficiency states; and to estimate the risk for development of thrombosis in high-risk situations. Two hundred thirty patients from 71 families with a documented hereditary deficiency of a natural coagulation inhibitor were included in the study. The patient group comprised 69 patients from 25 families with AT-III deficiency, 86 patients from 27 families with PC deficiency, and 75 patients from 19 families with PS deficiency. Diagnosis of the deficiency state was made at each participating center. Clinical data were documented in a questionnaire that was completed during each patient’s visit to the participating center. The questionnaires were sent to the coordinating center (Vienna) and analyzed centrally. The probability of developing thrombosis was 80% to 90% for all deficiency states by 50 to 60 years of age, and this figure did not change considerably after data from the propositi were excluded. AT-III–deficient females developed thrombosis earlier in life compared with PC- and PS-deficient females due to a high thrombotic risk during pregnancy (40% in patients with AT-III deficiency) and oral contraceptive use. The clinical features of thromboembolism were similar in the three deficiency states except for a higher frequency of superficial thrombophlebitis in patients with PC and PS deficiencies. Mesenteric vein thromboses occurred in 4% to 10% of patients and in 2 of 8 patients as a recurrent event. The recurrence rate was 63% (60% of recurrent events occurred spontaneously) and did not differ significantly among the three deficiency states. Before 14 years of age only 1 of 80 surgical procedures and 0 of 21 leg injuries were followed by thrombosis. After 14 years of age thromboembolic events occurred after abdominal surgery or leg injury in one third of patients. Between 40% and 50% of symptomatic patients reported that they felt handicapped by a postthrombotic syndrome. We conclude that diagnosis of a coagulation inhibitor deficiency state should be made before 14 years of age. During childhood thrombosis prophylaxis cannot be regularly recommended but should be instituted after 13 years of age during/after abdominal surgery, including appendectomy, and after leg injury in AT-III–, PC-, and PS-deficient patients. The high recurrence rate (60% spontaneous recurrence) and the relatively high frequency of mesenteric vein thrombosis as a recurrent event favor introduction of long-term oral anticoagulant treatment after the first thrombotic event in patients with a documented hereditary deficiency of AT-III, PC, or PS.
Phenotypic Heterogeneity of Rat Arterial Smooth Muscle Cell Clones
Authors: Bochaton-Piallat Marie-Luce , Ropraz Patricia , Gabbiani Françoise , Gabbiani Giulio
Published: June 2011

Abstract
It is well accepted that smooth muscle cells (SMCs) cultured from normal rat arterial media have different morphological and biological features compared with SMCs cultured from experimental intimal thickening (IT) 15 days after endothelial injury. It is not known, however, whether the phenotypic modulation producing IT cells occurs in any medial SMCs or only in a particular SMC subpopulation. To distinguish among these possibilities, the phenotypic features of SMC clones derived from normal adult media and the IT 15 days after endothelial lesion were analyzed according to morphological appearance, replicative activity in the presence and absence of fetal calf serum, and [
3
H]thymidine incorporation and motile activity; these features were compared with those of the respective SMC parental populations. Two categories of SMC clones predominated: spindle clones, with morphological features similar to those of the parental population from the normal media, and epithelioid clones, with morphological features similar to those of the IT parental population. Both categories were present among clones produced from normal media and IT; however, spindle was more common among normal media clones, and epithelioid, among IT clones. The behavior in vitro was distinct for each category of clones and did not depend on their origin. Our results are compatible with the possibility that the SMC population of IT in vivo derives mainly from SMCs belonging to the category exhibiting epithelioid features in vitro.
On Quantifying Plaque Size and Intima-Media Thickness in Carotid and Femoral Arteries
Authors: Wendelhag Inger , Wiklund Olov , Wikstrand John
Published: June 2011

The aim of the present analysis in an ongoing observational study was to evaluate the possibility of measuring plaque size in ultrasound images from carotid and femoral arteries and the usefulness of quantitative plaque measurements in such a prospective study. Twenty-five patients with carotid plaques were identified in a group of patients with familial hypercholesterolemia (n=50) compared with 7 subjects in a low-risk control group (n=47). Only 20 of the 32 recorded plaques were accessible for quantitative follow-up measurements of area, base length, and thickness, which represents only 21% of all subjects investigated. In contrast, paired observations of intima-media thickness in the common carotid artery were available in 98% and in the carotid bulb in 87% of the subjects investigated. In those with paired observations of plaque area available, the data indicated a close relationship between the 2-year change recorded in plaque area and the 2-year change in intima-media thickness measured in a 10-mm-long predefined section of the carotid bulb (
r
=.81,
P
<.001, n=19). The corresponding relationship between change in plaque area and change in a 10-mm-long section of the common carotid artery was
r=
.38 and
P
<.05 (n=20). Quantitative measurements of plaques in the femoral arteries were also performed, but the results from these measurements were in most cases judged not to be useful. However, measurements of intima-media thickness in a 15-mm-long predefined section of the common femoral artery may be performed in a reproducible way in most patients. We conclude that the usefulness of plaque area measurements in prospective studies of the carotid artery seems limited because plaques available for quantitative measurements are present in only a small proportion of subjects. However, reproducible measurements of intima-media thickness in a predefined section of the carotid bulb are achievable in most subjects, and our data indicate that the changes recorded over time in the carotid bulb closely mirror changes occurring in the size of atherosclerotic plaques within the carotid artery region. In addition, present data indicate that measurements of intima-media thickness in the common carotid artery complement measurements performed in the carotid artery bulb in the study of early atherosclerosis.
Distribution in Healthy and Coronary Populations of the Methylenetetrahydrofolate Reductase (MTHFR) C
677
T Mutation
Authors: Wilcken David E.L. , Wang Xing L. , Sim Ah Siew , McCredie R. Michael
Published: June 2011

Modest elevations of circulating homocyst(e)ine are common in patients with vascular disease. We explored in normal and coronary artery disease (CAD) populations the distribution of a mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene that results in enzyme thermolability and reduced activity and in homocyst(e)ine elevation to assess its relevance to risk. We identified the C to T substitution at the MTHFR locus and compared the distributions of genotypes in 565 patients aged ≤65 years without and with angiographically documented CAD and in 225 healthy subjects. In the patients, we also assessed interrelations between genotypes and CAD occurrence and severity, as well as standard risk factors. The frequency of homozygotes for the mutation was the same in patients with and without CAD and in healthy subjects (11.6%, 11.0%, and 10.7%, respectively;
P
>.5 for each). There was also no excess among the 419 patients with severe disease (ie, one or more vessels with >50% luminal obstruction) compared with those with no or mild CAD (odds ratio: 1.004; 95% confidence interval: 0.59 to 1.70). Homozygosity for the mutation was also not associated with a history of myocardial infarction or the presence or severity of angina. However, body mass index increased linearly with the presence of the mutant allele (
P
=.005), and the mutation and hypertension were weakly associated (
P
=.036). We conclude that the MTHFR genotype is not a risk factor for coronary disease in this Australian population but that the strong association found with body mass index should be explored further.
Interleukin-1β in Coronary Arteries of Patients With Ischemic Heart Disease
Authors: Galea Joseph , Armstrong Johanna , Gadsdon Patricia , Holden Hazel , Francis Sheila E. , Holt Cathy M.
Published: June 2011

Interleukin-1β (IL-1β ) is known to have a number of effects on the different cell types present within coronary arteries. In this study we identified the location and phenotype of cells containing IL-1β in human coronary artery specimens from patients suffering from either coronary atherosclerosis or cardiomyopathy and correlated the presence of IL-1β with disease severity. Luminal endothelial cells, adventitial vessel wall cells, and macrophages were double labeled immunohistochemically for IL-1β protein and a cell type–specific monoclonal antibody for either endothelial cells or macrophages. In situ hybridization was performed to locate the presence of IL-1β mRNA within the coronary artery wall. In this study IL-1β protein was found to be increased in the adventitial vessel walls of atherosclerotic coronary arteries compared with coronary arteries from nonischemic cardiomyopathic hearts. This increase was directly proportional to the severity of coronary atherosclerosis. IL-1β protein was also detected in luminal endothelium and macrophages of atherosclerotic coronary arteries and coronary arteries from nonischemic cardiomyopathic hearts. IL-1β mRNA was found in luminal endothelial cells, adventitial vessel endothelial cells, and macrophages. We conclude that IL-1β is produced by endothelial cells and macrophages in coronary arteries from ischemic hearts and to a lesser extent from nonischemic cardiomyopathic hearts.
Lymphocyte Populations in Atherosclerotic Lesions of ApoE −/− and LDL Receptor −/− Mice
Authors: Roselaar Simon E. , Kakkanathu Paul X. , Daugherty Alan
Published: June 2011

Lymphocytes are prominent components of human atherosclerotic lesions, but their presence in murine models of disease has not been confirmed. Lymphocyte subpopulations have been identified in apoE −/− and LDL receptor −/− mice fed a cholesterol-enriched diet for up to 3 months. ApoE −/− mice had higher serum cholesterol concentrations than did LDL receptor −/− mice during most of the feeding period, primarily due to large increases in VLDL concentrations. Total area of atherosclerotic lesions was greater at all times in apoE −/− than LDL receptor −/− mice (lesion area after 3 months on cholesterol-enriched diet: apoE −/−, 993±193 and LDL receptor −/−, 560±131 μm2×103, mean±SEM, n=6 in each group). Lesions in apoE −/− mice contained larger macrophage-rich necrotic cores and more calcification than did those in LDL receptor −/− mice. Immunocytochemical analyses of tissue sections of ascending aortas performed with monoclonal antibodies to T and B lymphocytes and macrophages revealed that T lymphocytes immunoreactive for Thy 1.2, CD5, CD4, and CD8 were observed in lesions from both strains, but no B lymphocytes were detected. The density of Thy 1.2+T lymphocytes in lesions was greatest at 1 month (apoE −/−, 98±23 and LDL receptor −/−, 201±40 lymphocytes/mm2, n=6 in each group), decreasing in apoE −/− mice to 12±3 and in LDL receptor −/− mice to 51±20 lymphocytes/mm2at 3 months. The presence of T lymphocytes in murine atherosclerotic lesions makes these animals potentially useful for studying the involvement of the immune system in atherogenesis.
Heparin-Induced Overexpression of Basic Fibroblast Growth Factor, Basic Fibroblast Growth Factor Receptor, and Cell-Associated Proteoheparan Sulfate in Cultured Coronary Smooth Muscle Cells
Authors: Skaletz-Rorowski Adriane , Schmidt Annette , Breithardt Günter , Buddecke Eckhart
Published: June 2011

Basic fibroblast growth factor (bFGF), a potent mitogen for arterial smooth muscle cells (SMCs), plays a pivotal role in the pathogenesis of arteriosclerosis and restenosis. Heparin in nanogram quantities may promote or even be required for binding of bFGF to its cognate receptor. Conversely, heparin in microgram doses is a strong inhibitor of arterial SMC replication in vitro and in vivo. Bovine coronary SMCs (cSMCs) express bFGF, bFGF receptor (FGF-R1), and cell membrane–integrated proteoheparan sulfate (HSPG). These three molecules are known to form a trimolecular complex that promotes signal transduction and mitogenesis. The bFGF synthesized by cSMCs is distributed to an intracellular and a pericellular compartment. Resting cultured cells retain about 80% of their bFGF intracellularly; 20% is found in the pericellular region. During proliferation, 70% to 80% of total bFGF is expressed in the pericellular compartment. Trypsinization generates soluble forms of the complex of bFGF with the ectodomains of the bFGF receptor and cell membrane–integrated HSPG in the pericellular compartment, thus allowing quantification of pericellular bFGF by a highly specific enzyme immunoassay. Standard heparin inhibits the proliferation of cSMCs by up to 80% in a concentration range between 10 and 100 μg/mL medium in a dose-dependent manner but increases the protein content of cSMCs compared with proliferating control cells. The heparin-induced increase in cellular protein content includes a 60% to 100% increase in the expression of pericellular bFGF, FGF-R1, and cell membrane–integrated HSPG. Thus, under heparin treatment, the heparan sulfate side chains of cell membrane–integrated HSPG incorporate more [
35
S]sulfate, and the proportion of [
35
S]heparan sulfate among total glycosaminoglycans increases from 36% to 52%. Fluorescence-activated cell sorting analysis and [
3
H]thymidine incorporation experiments provide evidence for multiple effects of heparin, including blocks at early and late checkpoints of the cell cycle in heparin-treated cells. These results indicate that heparin, despite its antiproliferative potency, stimulates the expression of all components of the bFGF system even in coronary SMCs in which growth is inhibited.
Effect of Immunization With Homologous LDL and Oxidized LDL on Early Atherosclerosis in Hypercholesterolemic Rabbits
Authors: Ameli Sean , Hultgårdh-Nilsson Anna , Regnström Jan , Calara Federico , Yano Juliana , Cercek Bojan , Shah Prediman K. , Nilsson Jan
Published: June 2011

Although the existence of an immune response against modified lipoproteins in atherosclerosis has been observed in experimental animals as well as in humans, the precise pathophysiological relevance of these findings remains unclear. In this study we determined the effect of an immunization with homologous LDL and copper-oxidized LDL on the formation of atherosclerotic plaque in hypercholesterolemic rabbits. Immunizations were performed at the start of a cholesterol-rich diet and 3 weeks later. After 16 weeks, antibodies against oxidized LDL had developed in rabbits given hypercholesterolemic diet alone, but the titers were increased by twofold in rabbits immunized with oxidized LDL as well as in rabbits immunized with LDL, suggesting that the LDL had also become oxidized during the preparation and/or immunization procedure. Immunization with LDL and oxidized LDL reduced atherosclerotic lesions in the proximal aorta by 74% (P<.05) and 48% (P=NS), respectively. The cellular composition of the lesions was not affected by the immunizations. These results support the hypothesis that an immune response against modified LDL has a protective effect against the development of early atherosclerotic lesions.
Inhibition of Thrombin Generation by Aspirin Is Blunted in Hypercholesterolemia
Authors: Szczeklik Andrzej , Musial Jacek , Undas Anetta , Swadzba Jakub , Gora Pawel F. , Piwowarska Wieslawa , Duplaga Mariusz
Published: June 2011

Recent evidence indicates that aspirin inhibits thrombin generation in clotting blood. We noticed that this effect was less pronounced in patients with hypercholesterolemia. The aim of the study was to prove this observation. The effects of aspirin on thrombin generation were evaluated in (1) 46 healthy volunteers, 2 hours after ingestion of a single, 500-mg dose and (2) 28 survivors of myocardial infarction who took 300 mg aspirin/d for 2 weeks. In both populations, two well-matched subgroups were distinguished, using a serum cholesterol level of 6.2 mmol/L (240 mg/dL) and an LDL cholesterol level of 4.0 mmol/L (155 mg/dL) as borderline. Thrombin generation was monitored ex vivo in blood emerging from a skin microvasculature injury and additionally, in a single-dose study in vitro in recalcified plasma. Aspirin depressed thrombin generation in the group of subjects with serum cholesterol <6.2 mmol/L and LDL cholesterol <4.0 mmol/L but not in the group with high blood cholesterol levels. Inhibitory effects of aspirin were more pronounced after the 2-week treatment than after a single dose. There was a significant correlation between total serum cholesterol or LDL cholesterol and total amount of thrombin generated after aspirin treatment. In subjects with high blood cholesterol levels, thrombin generation was not affected by aspirin. Blunting of aspirin action in hypercholesterolemia might be explained by (1) alterations in platelet lipid-protein matrix that render their membrane proteins less accessible for acetylation by aspirin and (2) changes in composition and structure of plasma lipoproteins that diminish the chance of aspirin to interact with prothrombin.
Improvement of Atherosclerosis and Stiffness of the Thoracic Descending Aorta With Cholesterol-Lowering Therapies in Familial Hypercholesterolemia
Authors: Tomochika Yasuaki , Okuda Fumio , Tanaka Nobuaki , Wasaki Yuichiro , Tokisawa Ikuo , Aoyagi Shumpei , Morikuni Chieko , Ono Shiro , Okada Kazuyoshi , Matsuzaki Masunori
Published: June 2011

The thoracic aorta is frequently involved in atherosclerotic lesions associated with familial hypercholesterolemia (FH). Transesophageal echocardiography (TEE) allows quantitative evaluation of the wall properties of the thoracic aorta. Using TEE, we tested whether atherosclerosis of the thoracic aorta in FH could be improved by cholesterol-lowering therapies. The subjects investigated were 22 FH patients and 22 age-matched normal subjects. The descending aorta (DA) was divided into four longitudinal portions of equal length. Atheromatous lesions of each portion of the DA were scored by character and extension of lesions by biplane two-dimensional TEE. The scores of atheromatous lesions from all four portions of the DA were added together to give the total atheromatous score (TAS). We also measured instantaneous dimensional changes of the DA in a cardiac cycle by M-mode TEE and blood pressure by a cuff method and calculated the stiffness parameter β (ln[SBP/DBP]/[Dmax−Dmin]/Dmin), where SBP is the systolic arterial blood pressure, DBP is the diastolic arterial blood pressure, Dmax is the maximum aortic dimension during the ejection period, and Dmin is the minimum aortic dimension during the preejection period. TAS was higher in FH (3.70±1.32) than normal (0.62±0.54,
P
<.0001) subjects. β in FH (10.35±4.87) was greater than in normal (5.10±1.25,
P
<.0001) subjects, but there were no significant differences of DA dimensions between the groups. In both normal subjects and FH patients, β correlated with age (
r
=.52,
P
<.02 and
r
=.59,
P
<.005, respectively). In FH patients, β and TAS correlated well with pretreatment total cholesterol levels (
r
=.43,
P
<.05 and
r
=.60,
P
<.005, respectively). In 12 of 22 FH patients, strict cholesterol-lowering therapies with diet and cholesterol-lowering drugs (pravastatin and probucol) were undertaken for 13 months. Cholesterol levels were significantly decreased from 333±45 to 219±39 mg/dL (
P
<.0001); this was associated with significant decreases in β and TAS (from 9.88±5.03 to 7.88±3.92,
P
<.005, and from 3.61±1.50 to 2.94±1.22,
P
<.0005, respectively). In FH patients, the incidence and severity of morphological and physiological atherosclerosis of the DA were significantly higher than in age-matched normal subjects. A significant regression of atherosclerosis was achieved by strict cholesterol-lowering therapies in relatively young FH patients.
Human Endothelial Cells Exposed to Oxidized LDL Express hsp70 Only When Proliferating
Authors: Zhu Weimin , Roma Paola , Pirillo Angela , Pellegatta Fabio , Catapano Alberico Luigi
Published: June 2011

Oxidized LDL (OxLDL), a causal factor in atherosclerosis, is cytotoxic and triggers the expression of various heat shock proteins (hsps), among which is hsp70, in cultured animal and human cells. hsps constitutively act as molecular chaperones and in situations of stress protect other cellular proteins from potential denaturation caused by cytotoxic stimuli. The sensitivity of endothelial cells to OxLDL toxicity and accordingly the level of hsp70 expression depend on cell density. While confluent cells were relatively resistant to OxLDL toxicity and were not induced to express hsp70 when challenged with the lipoprotein (up to 800 μg/mL), sparse cells exhibited a concentration- and time-dependent expression of inducible hsp70, which increased up to fivefold to sixfold in unchallenged cells. Neither the activity of receptors recognizing OxLDL nor potentially protective cell products affected the stress response. Rather, we demonstrated that cell proliferation, which is high for sparse cultures and wound-healing monolayers, is responsible for these observations. We also demonstrated that the lipid moiety of OxLDL essentially accounts for the hsp-inducing effect of the lipoprotein. OxLDL has been detected in atherosclerotic lesions, which also show an increase of immunoreactive hsp72/73. We speculate that, in vivo, rapidly growing cells, such as those of lesion-prone areas, are more sensitive to the toxicity of OxLDL than are quiescent cells and that an increased expression of hsp70 may allow proliferating cells an increased chance of survival.
Interindividual and Intraindividual Variability in Plasma Fibrinogen, TPA Antigen, PAI Activity, and CRP in Healthy, Young Volunteers and Patients With Angina Pectoris
Authors: de Maat Moniek P.M. , de Bart Anton C.W. , Hennis Bart C. , Meijer P. , Havelaar Adrie C. , Mulder Paul G.H. , Kluft Cornelis
Published: June 2011

We compared intraindividual and interindividual variability in the plasma levels of fibrinogen, tissue-type plasminogen activator (TPA) antigen, plasminogen activator inhibitor (PAI) activity, and C-reactive protein (CRP) in 20 healthy, young individuals and 26 patients with stable angina pectoris (AP) who were at higher risk for cardiovascular disease. For each of the four parameters, the contribution of the intraindividual variation to the total variance (13% and 9% for fibrinogen, 3% and 5% for TPA antigen, 4% and 20% for ln[PAI activity], and 14% and 9% for ln[CRP] for the healthy volunteers and AP patients, respectively) was smaller than the contribution from the interindividual variation. These results indicate that single sampling is sufficient to assess an individual level for TPA antigen and PAI activity, whereas duplicate sampling for fibrinogen and triplicate sampling for CRP are recommended. In an epidemiological study the sample sizes, based on the variances found in the transverse part of the study, needed to detect a 15% difference between the two groups (with α=.01 and a statistical power=.90) are 31 and 40 for fibrinogen, 568 and 146 for TPA antigen, 603 and 119 for PAI activity, and 1490 and 2263 for CRP in healthy volunteers and patients with AP, respectively. Additionally, we studied the contribution of genetic polymorphisms of the Bβ-fibrinogen (
Bcl
I and G→A
−455
) and PAI activity (
Hin
dIII and CA-repeat) genes to intraindividual and interindividual variation. Fibrinogen genotypes were associated with plasma fibrinogen levels in the volunteers but not in the AP patients. No effects of fibrinogen or PAI polymorphisms on intraindividual variation were observed in either healthy individuals or AP patients. In this study intraindividual variation in plasma levels of the cardiovascular risk indicators fibrinogen, TPA antigen, PAI activity, and CRP was small when compared with the interindividual variation in healthy, young volunteers and patients with stable AP.
Effects of a Major Gene for Apolipoprotein A-I Concentration Are Thyroid Hormone Dependent in Mexican Americans
Authors: Blangero John , Williams-Blangero Sarah , Mahaney Michael C. , Comuzzie Anthony G. , Hixson James E. , Samollow Paul B. , Sharp R. Mark , Stern Michael P. , MacCluer Jean W.
Published: June 2011

Apolipoprotein A-I (apoA-I) is the principal protein component of HDL cholesterol. The thyroid hormone triiodothryonine (T
3
) is known to be a potent mediator of expression of the apoA-I structural gene (
APOA1
). Using complex segregation analysis, we detected a major gene influencing plasma concentration of apoA-I and examined its interaction with T
3
serum level in Mexican Americans participating in the San Antonio Family Heart Study. Strong evidence for a major locus with two alleles (
A
and
a
) determining apoA-I level was obtained when interaction with T
3
was allowed. The major gene appears not to be linked to the
APOA1
structural locus. Genotypes differed significantly in their relationships to T
3
level. The
AA
and
Aa
genotypes showed a positive relationship with T
3
level, while the rarer
aa
homozygote showed a strong negative relationship with T
3
. The relative variance in apoA-I concentration due to this major gene varied from 56% to 18%, depending on T
3
level. On average, the major gene accounts for 30% of apoA-I variation, and shared-household effects account for an additional 11%. These findings suggest that thyroid hormone has an important role in the genetic control of lipoprotein metabolism.