Correlations between peripheral differential leukocyte counts and carotid atherosclerosis in non-smokers

Molecular Pathways of Vulnerable Carotid Plaques at Risk of Ischemic Stroke: A Narrative Review

The concept of vulnerable carotid plaques is pivotal in understanding the pathophysiology of ischemic stroke secondary to large-artery atherosclerosis. In macroscopic evaluation, vulnerable plaques are characterized by one or more of the following features: microcalcification; neovascularization; lipid-rich necrotic cores (LRNCs); intraplaque hemorrhage (IPH); thin fibrous caps; plaque surface ulceration; huge dimensions, suggesting stenosis; and plaque rupture. Recognizing these macroscopic characteristics is crucial for estimating the risk of cerebrovascular events, also in the case of non-significant (less than 50%) stenosis. Inflammatory biomarkers, such as cytokines and adhesion molecules, lipid-related markers like oxidized low-density lipoprotein (LDL), and proteolytic enzymes capable of degrading extracellular matrix components are among the key molecules that are scrutinized for their associative roles in plaque instability. Through their quantification and evaluation, these biomarkers reveal intricate molecular cross-talk governing plaque inflammation, rupture potential, and thrombogenicity. The current evidence demonstrates that plaque vulnerability phenotypes are multiple and heterogeneous and are associated with many highly complex molecular pathways that determine the activation of an immune-mediated cascade that culminates in thromboinflammation. This narrative review provides a comprehensive analysis of the current knowledge on molecular biomarkers expressed by symptomatic carotid plaques. It explores the association of these biomarkers with the structural and compositional attributes that characterize vulnerable plaques.

Neutrophil/HDL-C, Lymphocyte/HDL-C and Monocyte/HDL-C in subjects with asymptomatic carotid atherosclerosis

BACKGROUND

Leukocyte count is a prognostic marker for cardiovascular diseases, with key role in atherosclerosis development. Specific number of neutrophils, lymphocytes and monocytes can predict cardiovascular risk, also in asymptomatic subjects. Among the lipoprotein fractions, HDL-C is a protective factor in the cardiovascular disorders. For the above reason, we have examined the peripheral count of leukocytes, neutrophils, lymphocytes and monocytes, and the ratios between neutrophils/HDL-cholesterol, lymphocytes/HDL-cholesterol, and monocytes/HDL-cholesterol, to evaluate the possible utility of the obtained values in progression of asymptomatic carotid atherosclerosis.

METHODS

We performed our analysis in a cohort of 100 subjects with asymptomatic carotid atherosclerosis, of which 43 men and 57 women. The data were expressed as medians and IQR. To analyse the differences in leukocyte, neutrophil, lymphocyte, monocytes count and their ratio with HDL-cholesterol the Mann-Whitney test was employed.

RESULTS

The peripheral count of leukocyte subtypes and the ratios, they change in relation to the number of cardiovascular risk factors and the degree of insulin resistance.

CONCLUSIONS

In this cohort of subjects, the percentage of observed cardiovascular risk factors significantly affect some leukocyte parameters. These results, allow us to underline the importance of the leukocyte indices in the evaluation of subjects with asymptomatic vascular atherosclerosis.

Leukocyte and Platelet Related Inflammatory Indicators and Risk of Carotid and Femoral Plaques: A Population-Based Cross-Sectional Study in Southeast China

The associations between several blood inflammatory indicators and risk of vascular plaques remain inconclusive. A total of 4596 native rural residents in Southeast China were enrolled from the Fuqing cohort study. Blood cell counts and their composite indexes including the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and 2 novel indicators (systemic immune inflammation index (SII) and systemic immune inflammation response index (SIRI)) were considered as inflammatory indicators. Common carotid and femoral intima-media thickness (IMT) and plaques were assessed using B-mode ultrasound. Unconditional or multinomial logistic regression was used to evaluate potential associations. The prevalence of multiple femoral plaques (defined as IMT ≥1.5 mm) was significantly higher among participants with the highest tertile of total leukocyte count (odds ratio, 1.78), neutrophil count (1.88), monocyte count (2.51), platelet count (1.68), NLR (1.93), PLR (1.57), SII (2.10), and SIRI (2.94). Higher levels of neutrophil count, platelet count, NLR, and SII were also found to have significant linear dose-response relationships with the prevalence of stenosis, especially in femoral arteries. In conclusion, several blood inflammatory biomarkers may contribute to, or are associated with, the presence of IMT ≥1.5 mm or stenosis especially in femoral arteries.

Neutrophil Extracellular Traps in Atherosclerosis and Thrombosis

Despite effective therapeutic and preventive strategies, atherosclerosis and its complications still represent a substantial health burden. Leukocytes and inflammatory mechanisms are increasingly recognized as drivers of atherosclerosis. Neutrophil granulocytes within the circulation were recently shown to undergo neutrophil extracellular trap (NET) formation, linking innate immunity with acute complications of atherosclerosis. In this chapter, we summarize mechanisms of NET formation, evidence for their involvement in atherosclerosis and thrombosis, and potential therapeutic regimens specifically targeting NET components.

Contemporary Lifestyle and Neutrophil Extracellular Traps: An Emerging Link in Atherosclerosis Disease

Neutrophil extracellular traps (NETs) are networks of extracellular genetic material decorated with proteins of nuclear, granular and cytosolic origin that activated neutrophils expel under pathogenic inflammatory conditions. NETs are part of the host's innate immune defense system against invading pathogens. Interestingly, these extracellular structures can also be released in response to sterile inflammatory stimuli (e.g., shear stress, lipidic molecules, pro-thrombotic factors, aggregated platelets, or pro-inflammatory cytokines), as in atherosclerosis disease. Indeed, NETs have been identified in the intimal surface of diseased arteries under cardiovascular disease conditions, where they sustain inflammation via NET-mediated cell-adhesion mechanisms and promote cellular dysfunction and tissue damage via NET-associated cytotoxicity. This review will focus on (1) the active role of neutrophils and NETs as underestimated players of the inflammatory process during atherogenesis and lesion progression; (2) how these extracellular structures communicate with the main cell types present in the atherosclerotic lesion in the arterial wall; and (3) how these neutrophil effector functions interplay with lifestyle-derived risk factors such as an unbalanced diet, physical inactivity, smoking or lack of sleep quality, which represent major elements in the development of cardiovascular disease.

Panoramic imaged carotid atheromas are associated with increased neutrophil count: both validated, independent predictors of near-term myocardial infarction

OBJECTIVES

Panoramic images (PXs) demonstrating calcified carotid artery atheromas (CCAAs) are associated with heightened risk of near-term myocardial infarction (MI). Elevated neutrophil counts (NC) within normal range 2,500-6,000 per mm³ are likewise associated with future MI signaling the role neutrophils play in the chronic inflammation process underlying coronary artery atherogenesis. We determined if CCAAs on PXs are associated with increased NC.

METHODS

Investigators implemented a retrospective study of PXs and accompanying medical records of white males ≥ 65 years treated by a VA dental service. Two groups (N = 60 each) were constituted, one with atheromas (CCAA+) and one without (CCAA-). Predictor variable was CCAA + and outcome variable was NC. Bootstrapping analysis determined the difference in mean NCs between two groups, significance set at ≤0.05.

RESULTS

The study group of (CCAA+) (mean age 75.9; range 69-91 years) demonstrated a mean NC of 4,843 per mm³ and control group (CCAA-) (mean age 75.3; range; 66-94) a mean NC of 4,108 per mm³. The difference between the groups was significant (p = 0.0008) (95% CI of difference of mean: -432, 431; observed effect size 736).

CONCLUSIONS

CCAAs on PXs of elderly white males are associated with elevated NC; amplifying need for medical consultation prior to invasive dental procedures.

Elevated White Blood Cell Count Resultant Atherogenesis is Associated With Panoramic-Imaged Carotid Plaque

PURPOSE

Atherosclerotic plaques develop as a result of a low-grade, chronic, systemic inflammatory response to the injury of endothelial cells arising from lipid deposition within the intima. Increased white blood cell count (WBCC) is both a validated "biologic marker" of the extent of this inflammatory process and a key participant in the development of subsequent atherosclerotic ischemic heart disease manifesting as myocardial infarction. We sought to determine if calcified carotid artery plaque (CCAP) on a panoramic image (PI), also a validated risk indicator of future myocardial infarction, is associated with increased WBCC.

PATIENTS AND METHODS

We retrospectively evaluated the PI and medical records of White male military veterans aged 55 years and older treated by a VA dental service. Established were 2 cohorts of patients, 50 having plaques (CCAP+) and 50 without plaques (CCAP-). Predictor variable was CCAP+; outcome variable was WBCC. Bootstrapping analysis determined the differences in mean WBCCs between groups. Statistical significance set at ≤ 0.05.

RESULTS

The study group, (mean age 74; range 59 to 91 years) demonstrated a mean WBCC of 8,062 per mm³. The control group, (mean age 72 range; 57 to 94) evidenced a mean WBCC of 7,058 per mm³. Bootstrapping analysis of WBCC values demonstrated a significant (P = .012) difference (95% confidence interval of difference of mean, -806, 742; observed effect size, 1004) between groups.

CONCLUSIONS

The presence of CCAP demonstrated on PIs of older Caucasian men is associated with elevated WBCC. Concomitant presence of CCAP on PI and increased WBCC (≥7,800 per mm³) amplifies need for medical consultation before intravenous anesthesia and maxillofacial surgical procedures.

Association of the Total White Blood Cell, Neutrophils, and Monocytes Count With the Presence, Severity, and Types of Carotid Atherosclerotic Plaque

Background: Previous studies have indicated that white blood cells (WBCs) might contribute to the development of atherosclerosis. However, the associations of WBCs and WBC subgroups with carotid atherosclerotic plaque (CAP) have not been compared. Methods: A cross-sectional study including 3,569 healthy Chinese adults was conducted between January 2016 and December 2018 in Zhengzhou, China, to explore the associations of WBC and WBC subtypes with the presence, severity, and types of CAPs. Fasting peripheral venous blood was collected for measurement of the total WBC and WBC subtype counts. The size, composition, and types of CAPs in the common carotid artery, the internal carotid artery, and the external carotid artery were measured bilaterally using B-mode ultrasound. Results: The total WBC, neutrophil, and monocyte counts showed significant associations with the presence of CAPs in men, but not in women, with the adjusted odds ratios (95% CI) in the highest (compared to the lowest) quartile 1.99 (1.33-2.97), 1.65 (1.10-2.47), and 2.17 (1.41-3.18) (P _trend = 0.004, P _trend = 0.004, and P _trend < 0.001), respectively. The three leukocyte counts were also significantly associated with the severity of CAPs, as judged by the count of CAPs, maximal internal carotid plaque thickness, and the plaque score (all P < 0.01, P _trend < 0.05). Compared with individuals without CAPs, those with echolucent plaques had significantly increased total WBC and neutrophil counts, whereas those with polytype plaques had a significantly increased monocyte count. Conclusion: WBC, neutrophil, and monocyte counts were significantly associated with the presence, severity, and types of CAPs in a healthy Chinese population.

Shared mechanisms of multimorbidity in COPD, atherosclerosis and type-2 diabetes: the neutrophil as a potential inflammatory target

Multimorbidity is increasingly common and current healthcare strategies are not always aligned to treat this complex burden of disease. COPD, type-2 diabetes mellitus (T2D) and cardiovascular disease, especially atherosclerosis, occur more frequently together than expected, even when risk factors such as smoking, obesity, inactivity and poverty are considered. This supports the possibility of unifying mechanisms that contribute to the pathogenesis or progression of each condition.Neutrophilic inflammation is causally associated with COPD, and increasingly recognised in the pathogenesis of atherosclerosis and T2D, potentially forming an aetiological link between conditions. This link might reflect an overspill of inflammation from one affected organ into the systemic circulation, exposing all organs to an increased milieu of proinflammatory cytokines. Additionally, increasing evidence supports the involvement of other processes in chronic disease pathogenesis, such as cellular senescence or changes in cellular phenotypes.This review explores the current scientific evidence for inflammation, cellular ageing and cellular processes, such as reactive oxygen species production and phenotypic changes in the pathogenesis of COPD, T2D and atherosclerosis; highlighting common mechanisms shared across these diseases. We identify emerging therapeutic approaches that target these areas, but also where more work is still required to improve our understanding of the underlying cellular biology in a multimorbid disease setting.

Acyclic Isoprenoid Attenuates Lipid Anomalies and Inflammatory Changes in Hypercholesterolemic Rats

The present study was aimed to explore the antihyperlipidemic and anti-inflammatory effect of acyclic isoprenoid on high fat diet fed rats. Hypercholesterolemia was induced by the diet comprising of the normal rat chow 84.3%, lard 5%, yolk powder 10%, cholesterol 0.2% and 0.5% bile salt were fed to the rats for the period of 8 weeks. The results showed that abnormally elevated levels of plasma lipid profiles. Three different doses of acyclic isoprenoid (20, 40 and 80 mg/kg b.w/day) were administered orally to hypercholesterolemia suffering rats for the period of 30 days. Among these three doses of acyclic isoprenoid, the dose 80 mg/kg b.w. was significantly decreased the plasma lipid profiles when compared to other two doses. The effect produced by acyclic isoprenoid (80 mg/kg b.w) was comparable to that of simvastatin. Therefore, 80 mg/kg b.w was fixed as a effective dose and used for further analyses. Acyclic isoprenoid administration reinstated the elevated levels of cardiac and inflammatory markers in both blood and serum of hypercholesterolemic rats. In addition, acyclic isoprenoid administration decreased activity of 3-hydroxy 3-methyl-glutaryl-CoA reductase and increased the activity of lecithin cholesterol acyl transferase. These findings suggest that the administration of acyclic isoprenoid was potentially ameliorated the cardiac marker enzymes and inflammatory markers in addition to its antihypercholesterolemic effect.

Methylomic profiles reveal sex-specific differences in leukocyte composition associated with post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a debilitating mental disorder precipitated by trauma exposure. However, only some persons exposed to trauma develop PTSD. There are sex differences in risk; twice as many women as men develop a lifetime diagnosis of PTSD. Methylomic profiles derived from peripheral blood are well-suited for investigating PTSD because DNA methylation (DNAm) encodes individual response to trauma and may play a key role in the immune dysregulation characteristic of PTSD pathophysiology. In the current study, we leveraged recent methodological advances to investigate sex-specific differences in DNAm-based leukocyte composition that are associated with lifetime PTSD. We estimated leukocyte composition on a combined methylation array dataset (483 participants, ∼450 k CpG sites) consisting of two civilian cohorts, the Detroit Neighborhood Health Study and Grady Trauma Project. Sex-stratified Mann-Whitney U test and two-way ANCOVA revealed that lifetime PTSD was associated with significantly higher monocyte proportions in males, but not in females (Holm-adjusted p-val < 0.05). No difference in monocyte proportions was observed between current and remitted PTSD cases in males, suggesting that this sex-specific difference may reflect a long-standing trait of lifetime history of PTSD, rather than current state of PTSD. Associations with lifetime PTSD or PTSD status were not observed in any other leukocyte subtype and our finding in monocytes was confirmed using cell estimates based on a different deconvolution algorithm, suggesting that our sex-specific findings are robust across cell estimation approaches. Overall, our main finding of elevated monocyte proportions in males, but not in females with lifetime history of PTSD provides evidence for a sex-specific difference in peripheral blood leukocyte composition that is detectable in methylomic profiles and that may reflect long-standing changes associated with PTSD diagnosis.

The association between autonomic dysfunction, inflammation and atherosclerosis in men under investigation for carotid plaques

Background

Autonomic dysfunction is a risk factor for cardiovascular disease (CVD), however, the exact mechanism linking autonomic dysfunction to cardiovascular disease is not known. In this study we hypothesized that autonomic dysfunction increases inflammation, which subsequently accelerates atherosclerosis. The aim of the current study was to investigate the association between autonomic tone, inflammation and atherosclerosis.

Methods

124 men under investigation for carotid atherosclerosis were examined for autonomic function (heart rate variability; HRV and baroreflex sensitivity; BRS), inflammatory markers (white blood cell count; WBCC and C-reactive protein; CRP) and degree of carotid atherosclerosis. The direct or indirect associations between autonomic function, inflammatory parameters and carotid plaque area were investigated with multiple linear regressions.

Results

Male subjects with prevalent CVD showed larger carotid plaque area, higher WBCC, and reduced BRS compared to subjects with no history of CVD. Further, BRS was inversely associated with carotid plaque area (r = -0.21, p = 0.018) as well as inflammatory parameters WBCC and CRP (r = -0.29, p = 0.001, and r = -0.23, p = 0.009, respectively), whereas HRV only was inversely associated with WBCC (r = -0.22, p = 0.014). To investigate if inflammation could provide a link between autonomic function and carotid atherosclerosis we adjusted the associations accordingly. After adjusting for WBCC and CRP the inverse association between BRS and carotid plaque area was attenuated and did not remain significant, while both WBCC and CRP remained significantly associated with carotid plaque area, indicating that low-grade inflammation can possibly link BRS to atherosclerosis. Also, after adjusting for age, antihypertensive treatment and cardiovascular risk factors, BRS was independently inversely associated with both WBCC and CRP, and HRV independently inversely associated with WBCC. WBCC was the only inflammatory marker independently associated with carotid plaque area after adjustment.

Conclusions

We demonstrate that autonomic dysfunction is associated with atherosclerosis and that inflammation could play an important role in mediating this relationship.

Association of peripheral differential leukocyte counts with dyslipidemia risk in Chinese patients with hypertension: insight from the China Stroke Primary Prevention Trial

The aim of the present study was to examine the association between peripheral differential leukocyte counts and dyslipidemia in a Chinese hypertensive population. A total of 10,866 patients with hypertension were enrolled for a comprehensive assessment of cardiovascular risk factors using data from the China Stroke Primary Prevention Trial. Plasma lipid levels and total leukocyte, neutrophil, and lymphocyte counts were determined according to standard methods. Peripheral differential leukocyte counts were consistently and positively associated with serum total cholesterol (TC), LDL cholesterol (LDL-C), and TG levels (all P < 0.001 for trend), while inversely associated with HDL cholesterol levels (P < 0.05 for trend). In subsequent analyses where serum lipids were dichotomized (dyslipidemia/normolipidemia), we found that patients in the highest quartile of total leukocyte count (≥7.6 × 10⁹ cells/l) had 1.64 times the risk of high TG [95% confidence interval (CI): 1.46, 1.85], 1.34 times the risk of high TC (95% CI: 1.20, 1.50), and 1.24 times the risk of high LDL-C (95% CI: 1.12, 1.39) compared with their counterparts in the lowest quartile of total leukocyte count. Similar patterns were also observed with neutrophils and lymphocytes. In summary, these findings indicate that elevated differential leukocyte counts are directly associated with serum lipid levels and increased odds of dyslipidemia.

Longitudinal associations between lymphocyte count and LDL cholesterol in a health screening population

BACKGROUND

Longitudinal associations between leukocyte subtype counts and LDL cholesterol have not been reported.

METHODS AND RESULTS

This is a retrospective observational study in a health screening population. Spearman's correlation coefficients were calculated between leukocyte subtype counts and LDL cholesterol levels at baseline and after four years. Using Cox regression models, hazard ratios (HRs) of hyper-LDL cholesterolemia for leukocyte subtype counts during four years of follow-up were calculated adjusted for age, sex, high-sensitivity C-reactive protein (hs-CRP) and other confounders. Spearman's correlation coefficients (p values) between changes in counts of neutrophil, lymphocyte, monocyte, basophil and eosinophil and changes in LDL cholesterol levels through 4 years were 0.02 (0.494), 0.12 (<0.001), 0.06 (0.016), 0.02 (0.524) and 0.03 (0.257), respectively among 1735 subjects who visited our medical check-up center, did not use anti-hyperlipidemic drugs and revisited after 4 years. Among 1992 followed subjects, 481 developed hyper-LDL cholesterolemia during four years (60.4 per 1000 person-years). The HRs (95% confidence intervals; p values) of hyper-LDL cholesterolemia for each one SD increase in counts of neutrophil, lymphocyte, monocyte, basophil and eosinophil were 1.08 (0.99-1.19; 0.085), 1.14 (1.04-1.25; 0.005), 1.05 (0.95-1.15; 0.339), 1.01 (0.92-1.11; 0.858) and 1.04 (0.95-1.14; 0.397), respectively.

CONCLUSIONS

Lymphocyte count and LDL cholesterol were longitudinally positively correlated and lymphocyte count was associated with incidence of hyper-LDL cholesterolemia independently of hs-CRP in a health screening population.

Metabolic syndrome and early carotid atherosclerosis in the elderly

AIMS

To investigate whether metabolic syndrome(MetS) can predict the new onset of carotid plaque or the progression of carotid intima-media thickness(C-IMT) and identify other associated factors in an elderly population without evidence of early carotid atherosclerosis.

METHODS

B-mode carotid ultrasonography was used to assess the presence of carotid plaque and the C-IMT at baseline and follow-up. Participants with carotid plaque or an increased C-IMT(≥1.0mm) at baseline were excluded from the study. The new occurrence of carotid plaque, defined as early carotid atherosclerosis and the progression of C-IMT, was evaluated. Multiple regression analyses were used to determine predictors of these findings.

RESULTS

A total of 370 participants over 60 years of age(median age=66 years, 34.1% men) were enrolled. After a median follow-up period of 25 months, 64 participants(17.3%) had newly developed carotid plaque. After adjusting for variables determined to be statistically significant in univariate analyses, a multivariable regression analysis showed that predictors of newly developed carotid plaque were metabolic syndrome(hazard ratio [HR]=1.916; 95% confidence interval [CI]: 1.059-3.466), white blood cell count(HR=1.313; 95% CI: 1.094-1.576) and vitamin B12(HR=1.001; 95% CI: 1.000-1.002) and total cholesterol(HR=1.009; 95% CI: 1.001-1.017) levels. A multiple linear regression analysis showed that the rate of change for C-IMT tended to be associated with the development of metabolic syndrome.

CONCLUSIONS

Metabolic syndrome is associated with the progression of early carotid atherosclerosis in the general population, suggesting that metabolic syndrome plays an important role in initiating the atherosclerotic process.

The value of C-reactive protein in symptomatic versus asymptomatic carotid artery stenosis

Inflammatory markers may help establish the diagnosis of carotid atherosclerotic disease and predict the progression and outcomes. We evaluated inflammatory markers in symptomatic and asymptomatic patients with moderate to severe carotid artery stenosis, including high-sensitivity C-reactive protein (hs-CRP), leukocyte count, leukocyte subgroups and erythrocyte sedimentation rate. There were 32 symptomatic and 16 asymptomatic patients (age ≥50 years) with moderate to severe carotid stenosis detected by color Doppler ultrasonography, and 22 individuals without atherosclerotic findings on Doppler ultrasonography. The mean hs-CRP was significantly greater in the symptomatic (p = 0.001) and asymptomatic (p < 0.001) patients than control subjects; there was no significant difference between symptomatic and asymptomatic patients in mean hs-CRP values. Compared with control subjects, asymptomatic patients had greater mean leukocyte count (p = 0.016). Compared with control subjects, symptomatic patients had greater mean neutrophil count (p = 0.012), monocyte count (p = 0.021) and erythrocyte sedimentation rate (p = 0.001). The hs-CRP was associated with moderate to severe carotid artery stenosis, but it did not differentiate symptomatic and asymptomatic patients.

White blood cell count is associated with carotid and femoral atherosclerosis

OBJECTIVE

Chronic low-grade inflammation is associated with atherosclerosis. Ultrasound imaging allows measurement of intima-media thickness (IMT) and plaque. We investigated the association between inflammatory markers and carotid and femoral atherosclerosis.

METHODS

We studied 554 subjects with primary dyslipidemia (57% men, median age 49 years) and 246 age- and sex-matched normolipidemic subjects. Carotid and femoral arteries were imaged bilaterally with a standardized protocol. Mean and maximum common carotid IMT (CC-IMT and MaxCC-IMT) and common femoral IMT (F-IMT and MaxF-IMT), and carotid and femoral plaque were assessed. Carotid atherosclerosis was defined by CC-IMT and/or plaque height >75th percentile of a reference population. White blood cell count (WBCC) was measured in all subjects. High-sensitivity C-reactive protein (CRP) was measured in 330 dyslipidemic subjects.

RESULTS

The age- and sex-adjusted probability of carotid atherosclerosis and femoral plaque increased by 20% (odds ratio [OR] 1.20; 95% CI, 1.10-1.31) and 25% (1.25; 1.13-1.38), respectively, for each 1000/mm(3) WBCC increment. WBCC was associated with age- and sex-adjusted CC-IMT and MaxCC-IMT (p<0.05, both), and F-IMT and MaxF-IMT (p<0.001, both). Adjustment for cardiovascular risk factors did not influence these associations. CRP was associated with CC-IMT and MaxCC-IMT (p<0.05, both), but the associations disappeared after adjustment for body mass index. CRP was unrelated to carotid plaque or measures of femoral atherosclerosis.

CONCLUSIONS

WBCC, but not CRP, related to early and advanced measures of atherosclerosis independently of risk factors. Our findings support using the heretofore undervalued WBCC as an easy-to-measure, low-cost diagnostic marker of atherosclerosis.

The combination of carotid and lower extremity ultrasonography increases the detection of atherosclerosis in type 2 diabetes patients

OBJECTIVE

To evaluate the prevalence of atherosclerosis detected by both carotid and lower extremity ultrasonography in hospitalized Chinese type 2 diabetic patients and to examine whether plaque formation in the carotid arteries could be an indicator of generalized atherosclerosis in type 2 diabetes mellitus.

METHODS

Totally, 709 hospitalized Chinese type 2 diabetic patients (men 357, women 352) aged from 18 to 88 years were included. Both carotid and lower extremity atherosclerosis were assessed by Doppler ultrasound. Atherosclerosis was defined as the presence of either the carotid or lower extremity plaque in any of the above-mentioned arteries segments. The prevalence of atherosclerosis was calculated, and the risk factors associated with atherosclerosis were evaluated using binary logistic regression.

RESULTS

The prevalence of atherosclerosis was 81.23% in male and 77.56% in female type 2 diabetic patients, respectively. There was no significant difference in the prevalence of atherosclerosis in patients between the sexes. The prevalence of atherosclerosis was significantly higher in the lower extremity arteries than in the carotid arteries (73.91% and 44.43%, respectively, P<.001). Atherosclerosis was significantly associated with smoking, age, duration of diabetes, systolic blood pressure, total number of white blood cells, and mean carotid and femoral intima-media thickness (IMT).

CONCLUSIONS

The prevalence of atherosclerosis was very high in Chinese inpatients with type 2 diabetes. Carotid atherosclerosis could not be an indicator of generalized atherosclerosis in type 2 diabetes. The combination of carotid and lower extremity ultrasound examination can significantly improve the detection of atherosclerosis in type 2 diabetes.

White blood cell subsets are associated with carotid intima-media thickness and pulse wave velocity in an older Chinese population: the Guangzhou Biobank Cohort Study

Cross-sectional associations between white blood cell (WBC) count, lymphocyte and granulocyte numbers, and carotid intima-media thickness (IMT) and brachial-ankle pulse wave velocity (PWV) were examined in a novel older Chinese community sample. A total of 817 men and 760 women from a sub-study of the Guangzhou Biobank Cohort Study had a full blood count measured by an automated hematology analyzer, carotid IMT by B-mode ultrasonography and brachial-ankle PWV by a non-invasive automatic waveform analyzer. Following adjustment for confounders, WBC count (β=0.07, P<0.001) and granulocyte (β=0.07, P<0.001) number were significantly positively related to PWV, but not lymphocyte number. Similarly, WBC count (β=0.08, P=0.03), lymphocyte (β=0.08, P=0.002) and granulocyte (β=0.03, P=0.04) number were significantly positively associated with carotid IMT, but only the association with lymphocyte count survived correction for other cardiovascular risk factors. In conclusion, higher WBC, particularly lymphocyte and granulocyte, count could be used, respectively, as markers of cardiovascular disease risk, measured through indicators of atherosclerosis and arterial stiffness. The associations for WBC count previously observed by others were likely driven by higher granulocytes; an index of systemic inflammation.

Lymphocyte count was significantly associated with hyper-LDL cholesterolemia independently of high-sensitivity C-reactive protein in apparently healthy Japanese

The aim of this study was to investigate the association between leukocyte subtype counts and hyper-LDL cholesterolemia, hypertriglyceridemia, and hypo-HDL cholesterolemia. Logistic regressions using hyper-LDL cholesterolemia, hypertriglyceridemia, and hypo-HDL cholesterolemia as a dependent variable and total leukocyte, basophil, eosinophil, neutrophil, lymphocyte, and monocyte counts as an independent variable were calculated adjusting for age, body mass index (BMI), high-sensitivity C-reactive protein (hs-CRP), smoking, drinking, and physical activity in apparently healthy Japanese men (1,803) and women (1,150). The odds ratio (OR) of hyper-LDL cholesterolemia for total leukocyte, eosinophil, and lymphocyte counts, the OR of hypertriglyceridemia for total leukocyte, eosinophil, neutrophil, and lymphocyte counts, and the OR of hypo-HDL cholesterolemia for total leukocyte, neutrophil, and lymphocyte counts were significant in men, and the OR of hyper-LDL cholesterolemia, for lymphocyte count, and the OR of hypo-HDL cholesterolemia for eosinophil count were significant in women. Lymphocyte count was significantly associated with hyper-LDL cholesterolemia independently of hs-CRP in apparently healthy Japanese.

Distinct infiltration of neutrophils in lesion shoulders in ApoE-/- mice

Inflammation and activation of immune cells are key mechanisms in the development of atherosclerosis. Previous data indicate important roles for monocytes and T-lymphocytes in lesions. However, recent data suggest that neutrophils also may be of importance in atherogenesis. Here, we use apolipoprotein E (ApoE)-deficient mice with fluorescent neutrophils and monocytes (ApoE(-/-)/Lys(EGFP/EGFP) mice) to specifically study neutrophil presence and recruitment in atherosclerotic lesions. We show by flow cytometry and confocal microscopy that neutrophils make up for 1.8% of CD45(+) leukocytes in the aortic wall of ApoE(-/-)/Lys(EGFP/EGFP) mice and that their contribution relative to monocyte/macrophages within lesions is approximately 1:3. However, neutrophils accumulate at sites of monocyte high density, preferentially in shoulder regions of lesions, and may even outnumber monocyte/macrophages in these areas. Furthermore, intravital microscopy established that a majority of leukocytes interacting with endothelium on lesion shoulders are neutrophils, suggesting a significant recruitment of these cells to plaque. These data demonstrate neutrophilic granulocytes as a major cellular component of atherosclerotic lesions in ApoE(-/-) mice and call for further study on the roles of these cells in atherogenesis.

Arterial Distensibility in Chronic Inflammatory Rheumatic Disorders

The pulse wave velocity (PWV), as an indicator of arterial distensibility, may play an important role in the stratification of patients based on the cardiovascular risk. PWV inversely correlates with arterial distensibility and relative arterial compliance. Decreased arterial distensibility alters arterial blood pressure and flow dynamics, and disturbes coronary perfusion. Systemic immune and inflammatory diseases, such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are associated with increased morbidity and mortality, predominantly due to adverse cardiovascular events. Systemic inflammation in these disorders may alter arterial compliance and arterial distensibility and, through this effect, lead to accelerated atherosclerosis. We have demonstrated an increase in the carotid-femoral (aortic) PWV that is a technique in which large artery elasticity is assessed from analysis of the peripheral arterial waveform, in patients with chronic inflammatory conditions such as RA, SLE, familial Mediterranean fever (FMF), Wegener’s granulomatosis (WG), sarcoidosis, psoriasis and psoriatic arthritis except Behçet’s disease (BD). In this review, the issue of arterial stiffness in RA, SLE, as well as WG, psoriasis, FMF, BD, sarcoidosis, systemic sclerosis (SS) and Takayasu's arteritis (TA) is overviewed.

Arterial distensibility in chronic inflammatory rheumatic disorders

The pulse wave velocity (PWV), as an indicator of arterial distensibility, may play an important role in the stratification of patients based on the cardiovascular risk. PWV inversely correlates with arterial distensibility and relative arterial compliance. Decreased arterial distensibility alters arterial blood pressure and flow dynamics, and disturbes coronary perfusion. Systemic immune and inflammatory diseases, such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are associated with increased morbidity and mortality, predominantly due to adverse cardiovascular events. Systemic inflammation in these disorders may alter arterial compliance and arterial distensibility and, through this effect, lead to accelerated atherosclerosis. We have demonstrated an increase in the carotid-femoral (aortic) PWV that is a technique in which large artery elasticity is assessed from analysis of the peripheral arterial waveform, in patients with chronic inflammatory conditions such as RA, SLE, familial Mediterranean fever (FMF), Wegener's granulomatosis (WG), sarcoidosis, psoriasis and psoriatic arthritis except Behçet's disease (BD). In this review, the issue of arterial stiffness in RA, SLE, as well as WG, psoriasis, FMF, BD, sarcoidosis, systemic sclerosis (SS) and Takayasu's arteritis (TA) is overviewed.

Association of neutrophil count with microembolization in patients with symptomatic carotid artery stenosis

BACKGROUND AND PURPOSE

Inflammation plays an important role in the initiation and progression of atherosclerosis but the contribution of neutrophils to this process is unclear. Asymptomatic cerebral microembolization can be detected by transcranial Doppler (TCD) and has been associated with increased risk of early stroke recurrence in patients with recently symptomatic carotid stenosis. In the present study, we sought to determine whether spontaneous microembolization was associated with neutrophil count in patients with recently symptomatic carotid stenosis.

METHODS

We continuously monitored Transcranial Doppler (TCD) spectra of middle cerebral artery blood flow ipsilateral to recently symptomatic carotid artery stenosis in 60 consecutive patients. Microembolic signals (MES) were diagnosed by experienced observers blinded to leukocyte count and high-sensitive C-reactive protein (hs-CRP) level measurement.

RESULTS

We found MES in 20 (33.3%) patients. Microembolization was associated with higher neutrophil counts (p=0.003). Differences in monocyte count and lymphocyte count between patients with MES and patients without MES were not statistically significant. Microembolization remained strongly associated with neutrophil count in multivariable analysis (p=0.003) whereas the association with hs-CRP was not significant.

CONCLUSIONS

Neutrophil count was associated with microembolization in patients with recently symptomatic carotid artery stenosis. Our findings suggest that neutrophils may play a role in the pathogenesis of stroke related to carotid atherosclerosis.

Accumulation of Myeloperoxidase-Positive Neutrophils in Atherosclerotic Lesions in LDLR −/− Mice

Objective— Atherosclerosis is a chronic inflammatory disease in which the immune system plays an important role. Neutrophils have not been thoroughly studied in the context of atherogenesis. Here, we investigated neutrophils in the development of murine atherosclerotic lesions.

Methods and Results— LDLR −/− mice were given a high-fat diet for different time periods and subsequently atherosclerotic lesions were studied by immunohistochemistry. Staining with anti–Ly-6G monoclonal antibody, a specific marker for neutrophils, revealed a marked accumulation of neutrophils during atherosclerosis development. Neutrophils were observed in the lesion, attached to the cap, and in the arterial adventitia. In addition, at some sites, neutrophil accumulation colocalized with endothelial E-selectin expression. Immunofluorescence double staining with anti-myeloperoxidase and anti–Ly-6G antibodies demonstrated the presence of myeloperoxidase in atherosclerotic lesions and its colocalization with neutrophils. After introducing the high-fat diet, levels of circulating myeloperoxidase in plasma strongly increased, with a peak at 6 weeks and a subsequent decrease to almost normal levels after 16 weeks of diet.

Conclusions— We here demonstrate for the first time the presence of neutrophils and myeloperoxidase in murine atherosclerotic lesions. As a major cell type in inflammatory responses the neutrophil may also be an important mediator in the development of atherosclerosis.

Revision in Reference Ranges of Peripheral Total Leukocyte Count and Differential Leukocyte Percentages Based on a Normal Serum C-Reactive Protein Level

BACKGROUND/PURPOSE

A higher total leukocyte count is a predictor of all-cause mortality and cardiovascular morbidity. The currently used reference range for peripheral total leukocyte count is wide (4.5-11.0 x 10(9)/L) and is associated with a low sensitivity in identifying non-infectious chronic diseases. We attempt to revise it based on a normal serum C-reactive protein (CRP) level.

METHODS

Study subjects were participants in a health check program at our hospital between 2000 and 2002. Those whose leukocyte analysis had been checked with the Sysmex Cell Counter NE-9000 were enrolled.

RESULTS

Significantly positive relationships between CRP level and total leukocyte count, neutrophil percentage, and monocyte percentage were found in all subjects (n = 14,114; p < 0.0001). In contrast, CRP level had a significantly inverse correlation with lymphocyte percentage (p < 0.0001). A proposed new reference range for total leukocyte count was estimated based on the data in the normal CRP level group (CRP < 0.1 mg/dL; n = 4839). To rest on the essence of statistics that the range of [mean +/- 2 standard deviations] contains approximately the middle 95% of observations in a sampled population, a new reference range for total leukocyte count was accordingly estimated to be 3.11-8.83 x 10(9)/L.

CONCLUSION

In view of the abundant evidence showing that a higher peripheral total leukocyte count is harmful to health, a down-correction of its upper reference range from the currently used 11.0 x 10(9)/L to the proposed 8.83 x 10(9)/L, based on a normal CRP level, should allow more abnormal health conditions to be identified and promote the usefulness of peripheral leukocyte analysis.

Body fat and circulating leukocytes in children

OBJECTIVE

To determine the effects of obesity on baseline levels of circulating granulocytes, monocytes, and lymphocyte subtypes in otherwise healthy children.

DESIGN

Two group comparison of leukocytes in normal weight control and overweight children.

SUBJECTS

In total, 38 boys and girls, ages 6-18 years, divided in two groups: normal weight, (NW, BMI<85th %tile, n=15) and overweight (OW, body mass index (BMI)>85th %tile, n=23).

MEASUREMENTS

BMI obtained from direct measures of height and body mass. Body fat was assessed by DEXA. Complete blood counts (CBC) were obtained by standard clinical hematology methods and surface antigen staining by flow cytometry.

RESULTS

The OW group compared to the NW group had increased total leukocytes counts (P=0.011), neutrophils (P=0.006), monocytes (P=0.008), total T (CD3) lymphocytes (P=0.022), and Helper T (CD4(+)) cells (P=0.003). Significant correlations were evident between leukocytes, and BMI percentile, BMI, or percent body fat. Neither lean body mass nor VO(2peak) per unit lean body mass were significantly related to any of the leukocytes. Percent body fat and BMI percentile were positively correlated (P<0.05) to total T cells (CD3) and/or helper T cells (CD4(+)).

CONCLUSION

A group of 23 overweight children displayed elevated counts in most types of circulating immune cells, suggesting the presence of low-grade systemic inflammation, a known pathogenetic mechanism underlying most long-term complications of obesity. Our data provide an additional rationale for the importance of avoiding or correcting pediatric obesity.

Carotid artery intima-media thickness is associated with insulin-mediated glucose disposal in nondiabetic normotensive offspring of type 2 diabetic patients

The aim of this study was to investigate whether insulin resistance is independently associated with early manifestations of atherosclerosis. To this end, 176 normotensive offspring of type 2 diabetic patients were subjected to euglycemic hyperinsulinemic clamp to assess insulin sensitivity. Early atherosclerosis was studied by ultrasonography of the common carotid artery. Of the total 176 subjects, 145 were glucose tolerant, 18 had impaired fasting glucose, and 13 had impaired glucose tolerance. Univariate correlations showed that age, body mass index, waist, blood pressure, 2-h postchallenge glucose, fasting insulin, triglycerides, interleukin-6, fibrinogen, and white blood cell count were significantly correlated with carotid intima-media thickness (IMT), whereas HDL cholesterol and glucose disposal showed a negative correlation. A stepwise multivariate regression analysis including sex, age, waist circumference, smoking status, systolic blood pressure, diastolic blood pressure, triglyceride, HDL cholesterol, 2-h postchallenge glucose, plasma IL-6, fibrinogen, white blood cell count, insulin-stimulated glucose disposal, and fasting insulin showed that the four variables that remained significantly associated with carotid IMT were waist circumference, insulin-stimulated glucose disposal, white blood cell count, and diastolic blood pressure, accounting for 33.7% of its variation. These findings support the concept that insulin sensitivity, rather than plasma insulin levels, is associated with early atherosclerosis in nondiabetic normotensive offspring of type 2 diabetic patients.

Elevated inflammation markers in pheochromocytoma compared to other forms of hypertension

OBJECTIVE

To investigate the effect of long-term catecholamine excess in pheochromocytoma on leukocyte and platelet count and on proteins of acute-phase response.

METHODS

Fifteen subjects with pheochromocytoma, 16 with primary aldosteronism, 18 with essential hypertension and 17 healthy controls were studied. Sixteen subjects with pheochromocytoma were investigated after tumor removal. Leukocyte, neutrophil and platelet count, as well as C-reactive protein were measured in all subjects, while fibrinogen, alpha(1)-antitrypsin, alpha(2)-macroglobulin, orosomucoid, transferrin and prealbumin were only measured in subjects with pheochromocytoma, primary aldosteronism and essential hypertension.

RESULTS

Subjects with pheochromocytoma showed significantly higher leukocyte [7.5 +/- 0.9 10(9)/l, p < 0.001 vs. primary aldosteronism (5.4 +/- 0.9 10(9)/l) and healthy controls (5 +/- 0.9 10(9)/l), p = 0.04 vs. essential hypertension (6.3 +/- 1.6 10(9)/l)], neutrophil (p < 0.001 vs. primary aldosteronism and healthy subjects) and platelet counts (p < 0.001 vs. primary aldosteronism; p = 0.01 vs. essential hypertension) compared to the other groups of subjects. Similar results were obtained for positive proteins of acute-phase response in subjects with pheochromocytoma [C-reactive protein: 0.62 +/- 0.52 mg/dl, p < 0.001 vs. healthy subjects (0.08 +/- 0.08 mg/dl), p = 0.001 vs. primary aldosteronism (0.17 +/- 0.19 mg/dl), p = 0.04 vs. essential hypertension (0.31 +/- 0.26 mg/dl); fibrinogen: p = 0.02 vs. primary aldosteronism; orosomucoid: p = 0.005 vs. primary aldosteronism; alpha(2)-macroglobulin: p = 0.009 vs. primary aldosteronism]. No significant differences were found in plasma levels of alpha(1)-antitrypsin, transferrin and prealbumin. Tumor removal led to a significant decrease in leukocyte (p = 0.004), neutrophil (p = 0.007) and platelet count (p = 0.003) and also to a significant decrease in acute-phase proteins (C-reactive protein: p = 0.03, fibrinogen: p = 0.008, alpha(1)-antitrypsin: p = 0.003, orosomucoid: p = 0.04).

CONCLUSIONS

Chronic catecholamine excess in pheochromocytoma is accompanied by an increase in inflammation markers which was reversed by the tumor removal.

The carotid-femoral (aortic) pulse wave velocity as a marker of arterial stiffness in familial Mediterranean fever

AIM

The purpose of the present study was to test the hypothesis that chronic inflammation impairs vascular function and leads to an arterial pulse wave velocity (PWV) increase in patients with familial Mediterranean fever (FMF).

PATIENTS AND METHODS

Twenty-three patients (17 women) with FMF, and 23 age- and sex-matched controls were recruited. Aortic PWV was determined by using an automatic device (Complior Colson, Createch Industrie, France) that allowed on-line pulse wave recording and automatic calculation of the PWV.

RESULTS

The PWV was slightly higher in patients with FMF than in control subjects (P=0.05). A significant correlation between PWV and age (P<0.001, r=0.67), body mass index (P<0.001, r=0.52) and leukocytes (P<0.001, r=0.66) was found in both groups combined and also in patients with FMF (P<0.001, r=0.73; P=0.01, r=0.52; P<0.001, r=0.69, respectively).

CONCLUSION

The PWV was slightly higher in patients with FMF compared with control subjects. Colchicine, an anti-inflammatory drug treatment, may have reduced the expected increased level of PWV in FMF patients. PWV is influenced by age, body mass index and leukocytes.

Relationship between white cell count, neuropsychologic outcome, and microemboli in 161 patients undergoing coronary artery bypass surgery

OBJECTIVE

Neuropsychologic impairment remains a problem after coronary artery bypass grafting. Relatively few studies have examined the potential role of the perioperative inflammatory response. This study aimed to determine whether there was any association between perioperative white cell count, microemboli, and cognitive performance after surgical intervention.

METHODS

White cell count and differential were prospectively measured perioperatively in 161 patients undergoing coronary artery bypass grafting. A neuropsychologic test battery (9 tests) was administered preoperatively and 6 to 8 weeks postoperatively in all 161 patients. Cerebral microemboli during cardiopulmonary bypass were also recorded by means of a transcranial Doppler scan of the right middle cerebral artery.

RESULTS

There was no correlation between microemboli and white cell counts at any time point. There were weak but significant inverse correlations between both preoperative (r = -0.19, P = .02) and postoperative (r = -0.21, P < .01) white cell count and a measure of overall neuropsychologic test performance (total z change score). There was a weak but significant positive correlation between the neutrophil count 10 minutes after bypass and the intraoperative microemboli count (r = 0.23, P = .01).

CONCLUSIONS

The correlation between white cell count and neuropsychologic outcome suggests that an inflammatory response might have a role in determining cognitive outcome after coronary artery surgery with cardiopulmonary bypass. The positive correlation between the microemboli during cardiopulmonary bypass and the neutrophil count 10 minutes after bypass is compatible with microemboli contributing to the inflammatory response. The patients' preoperative inflammatory status might also be predictive of the response to surgical intervention.

Identifying leukocyte gene expression patterns associated with plasma lipid levels in human subjects

Plasma lipid levels have been known to be risk factors for atherosclerosis for decades, and in recent years it has become accepted that inflammation is a crucial event in the pathogenesis of atherosclerosis. In this study, we investigated the relationship between plasma lipids and leukocytes by profiling and analyzing leukocyte gene expression in response to plasma lipid levels. We discovered several interesting patterns of leukocyte gene expression: (1) the expression of a number of immune response- and inflammation-related genes are correlated with plasma lipid levels; (2) genes involved in lipid metabolism and in the electron transport chain were positively correlated with triglycerides and low-density lipoprotein cholesterol (LDL) levels, and negatively correlated with high-density lipoprotein cholesterol (HDL) levels; (3) genes involved in platelet activation were negatively correlated with HDL levels; (4) transcription factors regulating lipogenesis-related genes were correlated with plasma lipid levels; (5) a number of genes correlated with plasma lipid levels were found to be located in the regions of known quantitative trait loci (QTLs) associated with hyperlipemia. Our findings suggest that leukocytes respond to changing plasma lipid levels by regulating a network of genes, including genes involved in immune response, and lipid and fatty acid metabolism.

Effects of rosiglitazone on postprandial leukocytes and cytokines in type 2 diabetes

OBJECTIVE

We postulated that in type 2 diabetes, the postprandial phase is a pro-inflammatory state that can be modulated by PPAR-gamma agonists. For this purpose, we determined the effects of rosiglitazone (8 mg/d) on postprandial leukocyte counts and pro-inflammatory cytokines (IL-6 and IL-8) in patients with type 2 diabetes.

METHODS AND RESULTS

A randomized, 8-week, cross-over, placebo-controlled, double-blind clinical trial was performed in 19 patients with type 2 diabetes. Standardized 6-h oral fat-loading tests were performed after each treatment period. During placebo treatment, blood leukocytes increased to a maximum 6-h postprandially, due to significant increases in neutrophils and lymphocytes. Concomitant postprandial increases were observed for IL-6 and IL-8, the major chemokines responsible for leukocyte recruitment. Rosiglitazone reduced the incremental area under the curves (dAUCs) for IL-6 (-63%, p<0.01) and IL-8 (-16%, p<0.05). The dAUC for leukocytes decreased with 37% (p<0.05), due to a specific reduction of neutrophils (-39%, p<0.05).

CONCLUSIONS

Rosiglitazone attenuated the postprandial increases of neutrophils, IL-6 and IL-8 in patients with type 2 diabetes. Since inflammation is a major force driving atherosclerosis, and man lives in a postprandial period most part of the day, a reduced inflammatory response after a meal may delay progression of atherosclerosis.

CONDENSED ABSTRACT

We postulated that in type 2 diabetes, the postprandial phase is a pro-inflammatory state that can be modulated by PPAR-gamma agonists. Rosiglitazone attenuated the postprandial increases of neutrophils, IL-6 and IL-8 in patients with type 2 diabetes. These effects may contribute to cardiovascular risk reduction.

Blood leukocyte count is a risk factor for intima-media thickening and subclinical carotid atherosclerosis in middle-aged men

Leukocytosis is known to predict future cardiovascular events even in subjects without coronary heart disease (CHD), but its association with early atherosclerotic changes has remained less certain. The aim of the present study was to investigate how the blood leukocyte count compares with several other risk factors for CHD in determining carotid artery intima-media thickness (IMT) and subclinical carotid atherosclerosis in a population sample. Both carotid arteries were investigated with high-resolution B-mode ultrasound in a community-based sample of 219 randomly selected men aged 50-59 years to calculate the mean maximum IMT (MMax IMT) of 12 standard sites. Risk factor assessment included several traditional biochemical risk factors, blood pressure, maximal oxygen consumption and work load on ergometry, life-style habits and hematologic parameters. As genetic determinants, apolipoprotein E and A-IV polymorphisms were studied. According to multivariate regression analysis, age (P<0.0001), blood leukocyte count (P<0.0001) and systolic blood pressure (P<0.042) were the only significant predictors of MMax IMT. MMax IMT increased linearly from the lowest tertile of blood leukocyte count (1.14+/-0.20mm) to the second (1.18+/-0.25 mm) and to the highest tertile (1.25+/-0.27 mm, P=0.019). This difference remained significant after adjustment with age, systolic blood pressure and smoking (P=0.032). Leukocytes seem to have an independent role in the early arterial damage and they may reflect subclinical disease. This implies that leukocyte count is undervalued in the diagnostics and prognostics of carotid atherosclerosis.

Mechanism and effect of thrombospondin-4 polymorphisms on neutrophil function

High-throughput genomic technology identified an association between a single nucleotide polymorphism (SNP), a proline (P387) rather than the predominant alanine (A387) at position 387 in thrombospondin-4 (TSP-4) and premature myocardial infarction. The inflammatory hypothesis of atherosclerosis invokes a prominent role of leukocytes and cytokines in pathogenesis. As the expression of TSP-4 by vascular cells permits its exposure to circulating leukocytes, the interactions of human neutrophils (polymorphonuclear leukocytes [PMNs]) with both TSP-4 variants were investigated. Phorbol 12-myristate 13-acetate (PMA)-stimulated PMNs adhered and migrated well and equally on the TSP-4 variants. Integrin alpha(M)beta2 was identified as the TSP-4 receptor mediating these responses, and the 3 epidermal growth factor (EGF)-like domains of TSP-4 harboring the SNPs interacted with the alpha(M)I-domain. Despite the similarity in these responses, the P387 variant induced more robust tyrosine phosphorylation of the stress-related mitogen-activated protein kinases (MAPKs): p38MAPK and c-Jun NH2-terminal kinase (JNK), as well as signal transducer and activator of transcription-1 (STAT1) and heat shock protein 27 (HSP27) than the A387 variant. Additionally, cells adherent to P387 TSP-4 variant released 4-fold more H2O2 and secreted 2-fold more interleukin 8 (IL-8) as compared with the A387. H2O2 release and p38MAPK activation were totally inhibited by blockade of alpha(M)beta2. Thus, alpha(M)beta2 plays a central role in proinflammatory activities of TSP-4 (P387) and may contribute to the prothrombotic phenotype associated with this variant.

Association between white blood cell count and carotid arteriosclerosis in Japanese smokers

Recent studies have shown the relationship between general inflammatory markers and ischemic heart and cerebrovascular diseases. Here we have investigated the potential association between the circulating white blood cell count and carotid arteriosclerosis in apparently healthy individuals. Between 1994 and 1998, 3455 subjects who had undergone general health screening tests including carotid ultrasonography were enrolled in this study. The intertertile cutoff points for the white blood cell count were 5.1 x 10(3) and 6.4 x 10(3) microL(-1) in the male subjects and 4.6 x 10(3) and microL(-1) in the female subjects. The prevalence of carotid plaque in the first (lowest), the second, and the third tertiles was 19, 28, and 28% in the male subjects, respectively (P < 0.0001), and 10, 15, and 14% in the female subjects, respectively (n.s.). The multivariate analysis showed that the male subjects in the second and third tertiles had increased risk for carotid plaque with odds ratios of 1.54 (95% CI 1.18-2.01) and 1.47 (95% CI 1.11-1.95), respectively, compared to those in the first tertile. When male subjects were subdivided according to their smoking status, the association between white blood cell count and carotid plaque was significant in those who smoked, but not in those who had never smoked. These data suggested the possible association between the circulating white blood cell count and formation of carotid plaque in male smokers, but not in male never smokers or in females, in an apparently healthy Japanese population.

Monocyte Count, But Not C-Reactive Protein or Interleukin-6, Is an Independent Risk Marker for Subclinical Carotid Atherosclerosis

BACKGROUND AND PURPOSE

Systemic inflammatory markers have been shown to predict future cardiovascular events, but whether they are associated with early atherosclerosis is uncertain. We investigated the relationship of inflammatory markers interleukin-6 (IL-6), high-sensitive C-reactive protein (hs-CRP), fibrinogen, monocyte count, and white cell count (WCC) with subclinical carotid atherosclerosis in a healthy community population.

METHODS

B-mode carotid ultrasound was performed on 1111 randomly selected male and female subjects aged 27 to 77 years. Serum IL-6, hs-CRP, plasma fibrinogen, monocyte count, and WCC were measured on all subjects, along with conventional cardiovascular risk factors.

RESULTS

Multivariate analysis showed that IL-6 (P<0.0001), fibrinogen (P=0.007), and monocyte count (P=0.001) were associated with carotid plaque formation in the whole population. Monocyte count remained associated independently with carotid plaque formation when adjusted further for conventional risk factors (odds ratio per SD increase in monocyte count 1.4; 95% CI, 1.13 to 1.73; P=0.002). IL-6 (P<0.0001), fibrinogen (P<0.0001), and monocyte count (P=0.04) were also associated with carotid intima-medial thickness (IMT) in the whole population. However, when adjusted further for conventional risk factors, none remained independently predictive of carotid IMT. Further analysis showed an age-monocyte interaction (P=0.03), with monocyte count being an independent predictor of carotid IMT in the older age group only (>53 years; P=0.003).

CONCLUSIONS

In a healthy community population, monocyte count is a better independent predictor of common carotid IMT and plaque formation than IL-6, hs-CRP, fibrinogen, and WCC. Monocyte count may represent an inexpensive, easy-to-measure risk marker for subclinical carotid atherosclerosis.

Lipaemia, Inflammation and Atherosclerosis

Atherosclerosis is the major cause of death in the world. Fasting and postprandial hyperlipidaemia are important risk factors for coronary heart disease (CHD). Recent developments have undoubtedly indicated that inflammation is pathophysiologically closely linked to atherogenesis and its clinical consequences. Inflammatory markers such as C-reactive protein (CRP), leucocyte count and complement component 3 (C3) have been linked to CHD and to hyperlipidaemia and several other CHD risk factors. Increases in these markers may result from activation of endothelial cells (CRP, leucocytes, C3), disturbances in adipose tissue fatty acid metabolism (CRP, C3), or from direct effects of CHD risk factors (leucocytes). It has been shown that lipoproteins, triglycerides, fatty acids and glucose can activate endothelial cells, most probably as a result of the production of reactive oxygen species. Similar mechanisms may also lead to leucocyte activation. Increases in triglycerides, fatty acids and glucose are common disturbances in the metabolic syndrome and are most prominent in the postprandial phase. People are in a postprandial state most of the day, and this phase is proatherogenic. Inhibition of the activation of leucocytes, endothelial cells, or both, is an interesting target for intervention, as activation is obligatory for adherence of leucocytes to the endothelium, thereby initiating atherogenesis. Potential interventions include the use of unsaturated long-chain fatty acids, polyphenols, antioxidants, angiotensin converting enzyme inhibitors and high-dose aspirin, which have direct anti-inflammatory and antiatherogenic effects. Furthermore, peroxisome proliferator activating receptor gamma (PPARgamma) agonists and statins have similar properties, which are in part independent of their lipid-lowering effects.

Inflammation and bone resorption as independent factors of accelerated arterial wall thickening in patients with rheumatoid arthritis

OBJECTIVE

We recently reported that rheumatoid arthritis (RA) patients had increased intima-media thickness (IMT) of the common carotid artery (CCA). The present longitudinal study was performed to determine whether the change in arterial thickness was accelerated in RA patients and to determine which factor was important in the progression of arterial wall changes.

METHODS

We studied 62 female RA patients with stable disease activity and 63 healthy female controls. IMT of the CCA was measured twice by high-resolution B-mode ultrasonography. The second examination was performed 18-36 months after the first, and changes were expressed as millimeters of increase per year. Baseline examinations included blood markers of inflammation and urinary calcium excretion (expressed as the calcium-to-creatinine ratio).

RESULTS

RA patients showed a significantly greater increase in IMT of the CCA compared with controls. In univariate analyses of the RA patient data, the C-reactive protein (CRP) level correlated with the increase in CCA IMT. Other markers of inflammation (the erythrocyte sedimentation rate and white blood cell and platelet counts) also showed significant positive associations with the annual increase in CCA IMT in multiple regression models when adjusted for age, smoking status, blood pressure, and serum cholesterol level. The urinary calcium-to-creatinine ratio was also significantly associated with an increase in CCA IMT. Moreover, both the CRP level and the urinary calcium-to-creatinine ratio were significantly and independently associated with the increase in IMT of the CCA.

CONCLUSION

Patients with RA have a higher rate of increase in thickening of the arterial wall. Inflammation and calcium mobilization are factors closely associated with the accelerated arterial wall changes.

Preoperative high leukocyte count: a novel risk factor for stroke after cardiac surgery

BACKGROUND

Stroke after cardiac surgery is a devastating complication. The relationship between white blood cell count (WBC) and perioperative cerebrovascular accident (CVA) has not been investigated. An effort was made to identify how preoperative WBC may relate to CVA development during or after cardiac surgery.

METHODS

Prospective data were collected from 7,483 patients who underwent coronary artery bypass grafting or valvular surgery or both. WBC was determined preoperatively and postoperatively. Differentiation of WBC was examined only preoperatively.

RESULTS

There were a total of 125 CVAs (10 transient ischemic attacks [TIAs], 115 strokes). WBC was significantly higher preoperatively and directly postoperatively in patients with stroke. Qualitative changes in preoperative WBC were also found in these patients (chi2; p < 0.001). The predictive power of the stepwise logistic regression model for CVA was greater when preoperative WBC was included. The risk for perioperative CVA increased starting at preoperative WBC of 9 x 10(9)/L (p = 0.044) and progressed in higher WBC ranges. WBC had a significant impact on CVA outcome (analysis of variance, p = 0.001).

CONCLUSIONS

Our studies have established the correlation between high preoperative WBC and stroke during or after cardiac surgery. Furthermore, elevated preoperative WBC was related to the clinical outcome of CVA. Preoperative measures aimed at preventing or treating conditions such as infections that may cause elevated WBC may be beneficial in the prevention of stroke during or after cardiac surgery.

Postprandial recruitment of neutrophils may contribute to endothelial dysfunction

Atherosclerosis is a low-grade inflammatory disease involving leukocytes, lipids, and glucose leading to endothelial dysfunction. Since activation of neutrophils by triglycerides and glucose has been described in vitro, we hypothesized that the postprandial phase is an inflammatory state affecting leukocytes, possibly contributing to endothelial dysfunction. We measured postprandial blood leukocyte counts, cytokines, hydroperoxides (HPOs), and flow-mediated vasodilation (FMD) in eight healthy males (age 23 +/- 2 years) after a FAT (50 g/m2) and GLUCOSE challenge (37.5 g/m2), a combination of both (MIXED test), and after WATER. All tests, except WATER, resulted in significantly impaired FMD (10% reduction) between t = 1 h and t = 3 h, accompanied by a significant increase of neutrophils (59% after FAT and 28% after GLUCOSE and MIXED), total plasma HPOs (15 to 31% increase), and plasma interleukin-8 (IL-8) (50-130% increase). WATER did not affect FMD, neutrophils, HPOs, or IL-8. Lymphocytes increased gradually in all tests (40-70% increase at t = 10 h compared with t = 0; P < 0.005), paralleling a gradual 3- to 5-fold interleukin-6 increase. Monocyte and erythrocyte counts did not change in any test. In conclusion, the neutrophil increment during postprandial lipemia and glycemia with concomitant IL-8 and HPO increases may contribute to endothelial dysfunction. Lymphocyte increment is a nonspecific diurnal process. Postprandial intravascular inflammatory changes may be relevant for the pathogenesis of atherosclerosis.

Inflammation and infection in clinical stroke

Stroke has enormous clinical, social, and economic implications, and demands a significant effort from both basic and clinical science in the search for successful therapies. Atherosclerosis, the pathologic process underlying most coronary artery disease and the majority of ischemic stroke in humans, is an inflammatory process. Complex interactions occur between the classic risk factors for atherosclerosis and its clinical consequences. These interactions appear to involve inflammatory mechanisms both in the periphery and in the CNS. Central nervous system inflammation is important in the pathophysiologic processes occurring after the onset of cerebral ischemia in ischemic stroke, subarachnoid hemorrhage, and head injury. In addition, inflammation in the CNS or in the periphery may be a risk factor for the initial development of cerebral ischemia. Peripheral infection and inflammatory processes are likely to be important in this respect. Thus, it appears that inflammation may be important both before, in predisposing to a stroke, and afterwards, where it is important in the mechanisms of cerebral injury and repair. Inflammation is mediated by both molecular components, including cytokines, and cellular components, such as leukocytes and microglia, many of which possess pro- and/or antiinflammatory properties, with harmful or beneficial effects. Classic acute-phase reactants and body temperature are also modified in stroke, and may be useful in the prediction of events, outcome, and as therapeutic targets. New imaging techniques are important clinically because they facilitate dynamic evaluation of tissue damage in relation to outcome. Inflammatory conditions such as giant cell arteritis and systemic lupus erythematosus predispose to stroke, as do a range of acute and chronic infections, principally respiratory. Diverse mechanisms have been proposed to account for inflammation and infection-associated stroke, ranging from classic risk factors to disturbances of the immune and coagulation systems. Considerable opportunities therefore exist for the development of novel therapies. It seems likely that drugs currently used in the treatment of stroke, such as aspirin, statins, and modulators of the renin-angiotensin-aldosterone system, act at least partly via antiinflammatory mechanisms. Newer approaches have included antimicrobial and antileukocyte strategies. One of the most promising avenues may be the use of cytokine antagonism, for example, interleukin-1 receptor antagonist.