Relation of serum cytokine concentrations to cardiovascular risk factors and coronary heart disease

The association of social status and blood pressure with markers of vascular inflammation

OBJECTIVE

Low socioeconomic status (SES) is associated with low-grade inflammation. Vascular inflammation often accompanies high blood pressure (BP) and has clinical implications for future vascular diseases, including atherosclerosis. Elevated plasma levels of soluble intercellular adhesion molecule-1 (sICAM-1) and endothelin-1 (ET-1) are reliable indicators of vascular inflammation. We examined the associations among BP, social status, and sICAM-1 and ET-1 levels in 121 European American and African American men and women.

METHODS

Social status of the subjects was determined by using the Hollingshead Two Factor Index of Social Position scale, and plasma sICAM-1 and ET-1 levels were assessed using immunoassays.

RESULTS

Correlation analyses revealed positive correlations among plasma sICAM-1 levels, BP, and social status. Levels of ET-1 were also significantly correlated with BP (p < .01) and social status (p < .001). When subjects were categorized into three social classes, sICAM-1 levels were significantly higher in the lowest social class as compared with the upper (p < .05) or middle (p < .01) class. The levels of ET-1 were higher in the low (p < .01) and middle (p < .05) social classes as compared with the upper class. Multiple hierarchic regression analyses revealed that even after controlling for demographic and health characteristics (gender, ethnicity, age, body mass index, and smoking) and systolic BP, social status accounted for additional variance of sICAM-1 or ET-1 levels.

CONCLUSION

These results suggest that low-social-status individuals may incur risk for future vascular diseases through vascular inflammation.

Systematic review: adipose tissue, obesity and gastrointestinal diseases

BACKGROUND

Obesity is increasingly being recognized as a risk factor for a number of benign and malignant gastrointestinal conditions. However, literature on the underlying pathophysiological mechanisms is sparse and ambiguous. Insulin resistance is the most widely accepted link between obesity and disease, particularly colorectal cancer. The recognition that intra-abdominal fat is immunologically active sheds new light not only on the pathogenesis of obesity-related gastrointestinal conditions, but also on inflammatory conditions such as Crohn's disease.

AIM

To describe the biology of adipose tissue, its impact on the immune system and explores the possible underlying mechanisms linking obesity to gastrointestinal diseases. It also looks at the role of mesenteric fat in determining severity and course of Crohn's disease.

METHODS

Relevant English-language literature and abstracts cited on MEDLINE database were reviewed.

RESULTS

Our recent finding of an association between obesity and subclinical bowel inflammation suggests that, apart from promoting generalized immune activation, fat also evokes local immune responses. We propose that the proinflammatory milieu promoted by obesity could underlie many of these associations and that the mechanism implicating insulin resistance may merely represent an epiphenomenon. In Crohn's disease, on the other hand, intra-abdominal fat may provide a protective mechanism.

CONCLUSION

The potential of adipose tissue as a therapeutic target is vast and needs exploration.

Inflammatory measures in children with obstructive sleep apnoea

AIM

To evaluate a range of inflammatory measures in children with obstructive sleep apnoea (OSA).

METHODS

In total, 44 children with polysomnographically defined OSA (30 boys; mean age: 7.3 +/- 3.7 years) and 69 control subjects (44 boys; mean age: 7.6 +/- 4 years) were recruited. Controls were screened for symptoms of OSA by questionnaire at the time of elective surgery that was unrelated to the upper airway. Blood samples were analysed for C-reactive protein, and cytokines IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, GM-CSF, IFN-gamma and TNF-alpha.

RESULTS

The majority of the children had mild OSA (32/44). Children with OSA (respiratory disturbance index 5.3 +/- 6.5 events/h) had significantly higher IFN-gamma and IL-8 levels than controls (P < 0.001 and 0.003, respectively), although correction for age, sex and body mass index reduced these differences (IFN-gammaP = 0.002, and IL-8 P = 0.051). There were no significant correlations between inflammatory measures and body mass index, respiratory disturbance index, or other sleep, desaturation, or arousal parameters including respiratory or spontaneous arousal indices, desaturation index or severity, sleep efficiency, or apnoea/hypopnoea duration in the OSA group.

CONCLUSION

Children with OSA, even of mild severity, have significantly elevated IFN-gamma levels and a trend towards elevated IL-8 levels compared with asymptomatic controls, consistent with a pro-inflammatory effect of OSA. These changes seen in mild OSA may precede changes in other pro-inflammatory cytokines found in studies of adults with more severe and long-standing disease, implying a potential benefit from early disease identification and intervention.

Serum lipids and low back pain: an association? A follow-up study of a working population sample

STUDY DESIGN

Cohort study with 5-, 10-, and 28-year follow-up.

OBJECTIVES

To examine associations between baseline serum lipid concentrations and later low back pain (LBP).

SUMMARY OF BACKGROUND DATA

Atherosclerosis of the lumbar vessels has been suggested as a mechanism leading to disc degeneration and LBP. Cholesterol is considered essential for atherosclerosis development.

METHODS

A sample (n = 902) of employees in an engineering company was examined for serum total cholesterol and triglycerides, body mass index (BMI), smoking, exercise, work history, and LBP in 1973. By November 2000, 232 subjects had died. In 1978, 748 (84% of the survivors), in 1983, 654 (76%), and in 2000, 546 (81%) responded to a follow-up questionnaire.

RESULTS

In men, baseline serum total cholesterol predicted new cases of radiating LBP in the 5-year follow-up (highest tertile vs. lowest: odds ratio [OR], 2.5; 95% confidence interval [CI], 1.1-5.9) and in the 10-year follow-up (OR, 2.8; 95% CI, 1.3-6.1), adjusted for age, occupational class, work history, BMI, smoking and exercise. Also, serum triglycerides predicted new cases in the latter examination (OR, 2.6; 95% CI, 1.2-5.8). In women, no associations were seen until the 10-year follow-up, when their results were similar to those in men. In the total material, serum total cholesterol predicted radiating LBP reported both at the 10- and the 28-year follow-up.

CONCLUSIONS

High serum lipids predicted incident radiating LBP, consistent with the atherosclerosis-LBP hypothesis.

Plasma fibrinogen levels and cardiovascular risk factors in Japanese schoolchildren

BACKGROUND

Plasma fibrinogen level has been recognized as an independent risk factor for atherosclerosis and its thrombotic complications in adults. The present study aimed to clarify the association between plasma fibrinogen levels and cardiovascular risk factors in Japanese children.

METHODS

A total of 294 schoolchildren (145 boys and 149 girls) aged 10-13 years in a town in Nagano Prefecture, Japan, were surveyed in 2000 for body mass index (BMI), plasma fibrinogen, serum C-reactive protein (CRP), serum total cholesterol, serum high-density lipoprotein (HDL) cholesterol, hemoglobin (Hb) A1c, and ratio of serum total cholesterol to serum HDL cholesterol (TCHR).

RESULTS

The mean value and standard deviation of plasma fibrinogen level among the schoolchildren was 226.0+/-39.7 mg/dL for boys and 245.3+/-40.9 mg/dL for girls; significantly higher for girls. Among plasma fibrinogen tertiles, serum CRP tended to increase with plasma fibrinogen in both boys and girls. An increasing trend was also found in serum total cholesterol in boys, and in TCHR, HbA1c and BMI in girls. Multiple linear regression analysis revealed significant associations of plasma fibrinogen with serum CRP and HbA1c in both sexes, with TCHR in boys, and with BMI in girls.

CONCLUSIONS

Plasma fibrinogen levels were associated with cardiovascular risk factors such as serum CRP, TCHR, HbA1c, and BMI in Japanese schoolchildren.

Is a leaky gut involved in the pathogenesis of intrahepatic cholestasis of pregnancy?

Increased gastrointestinal permeability has been demonstrated in several liver diseases. It may facilitate the absorption of gut-derived endotoxin-stimulating Kupffer cells to release proinflammatory cytokines or other potentially hepatotoxic compounds. We examined gastrointestinal permeability, plasma levels of anti-lipopolysacharides (anti-LPS), and four proinflammatory cytokines in 20 patients with intrahepatic cholestasis of pregnancy (ICP) compared with 22 normal pregnant and 29 non-pregnant women. Urinary excretion of sucrose and the urinary lactulose/mannitol (L/M) ratio after a standard oral load were used to assess gastrointestinal permeability. Anti-LPS (IgA, IgM, and IgG) were measured in peripheral blood by Human EndoCAb test kit; TNF-alpha, IL-1beta, IL-6, and IL-10 by Quantikine HS human immunoassays. Sucrose urinary excretion was similar in the three groups, indicating normal gastric permeability. The urinary L/M ratio was significantly higher in ICP than in the other groups [median (interquartile range): 0.018% (0.011-0.023) in ICP, 0.012% (0.009-0.016) in normal pregnancies, and 0.009% (0.008-0.012) in non-pregnant women, P < .01]. No significant differences were found in anti-LPS or cytokines plasma levels except slightly higher levels of IL-6 in ICP patients than in non-pregnant women (P < .05). Four of five women with abnormal urinary L/M ratio during ICP continued to show abnormalities in tests up to 2 years after delivery. In conclusion, an increased intestinal permeability was detected in ICP patients during and after pregnancy. A "leaky gut" may participate in the pathogenesis of ICP by enhancing the absorption of bacterial endotoxin and the enterohepatic circulation of cholestatic metabolites of sex hormones and bile salts.

Association of educational level with inflammatory markers in the Framingham Offspring Study

Socioeconomic position consistently predicts coronary heart disease; however, the biologic mechanisms that may mediate this association are not well understood. The objective of this study was to determine whether socioeconomic position (measured as educational level) is associated with inflammatory risk factors for coronary heart disease, including C-reactive protein, interleukin-6, soluble intercellular adhesion molecule-1, monocyte chemoattractant protein-1, and P-selectin. The study sample included 2,729 participants (53.4% women; mean age, 62 +/- 10 years) from the US Framingham Offspring Study cohort who attended examination cycles 3 (1984-1987) and 7 (1998-2001) and provided educational attainment data. Inflammatory markers were measured in fasting serum samples. Multivariable linear regression analyses were performed, adjusting for potential confounders including age, sex, and clinical risk factors. In age- and sex-adjusted analyses, educational attainment was significantly inversely associated with C-reactive protein (p < 0.0001), interleukin-6 (p < 0.0001), soluble intercellular adhesion molecule-1 (p < 0.0001), and monocyte chemoattractant protein-1 (p = 0.0004). After further adjustment for clinical risk factors, educational level remained significantly associated with C-reactive protein (p = 0.0002), soluble intercellular adhesion molecule-1 (p = 0.01), and monocyte chemoattractant protein-1 (p = 0.01). In conclusion, educational attainment is associated with inflammatory risk factors for coronary heart disease. The association provides evidence suggestive of a biologic pathway by which socioeconomic position may predispose to coronary heart disease.

Putting cardiovascular disease and vitamin D insufficiency into perspective

The aetiology of CVD is still not completely understood. The present review article summarises data supporting the hypothesis that an insufficient vitamin D status may contribute to the worldwide high prevalence of CVD. Human vitamin D status primarily depends on skin exposure to the UVB spectrum of the sunlight. Epidemiological data indicate that geographic latitude, altitude, season, and the place of residence (urban or rural) are associated with CVD mortality. Interestingly, all these factors also have an influence on human UVB exposure and thus on vitamin D status. Several mechanisms might be responsible for a protective role of vitamin D in CVD. These mechanisms include the inhibition of vascular smooth muscle proliferation, the suppression of vascular calcification, the down regulation of pro-inflammatory cytokines, the up regulation of anti-inflammatory cytokines, and the action of vitamin D as a negative endocrine regulator of the renin-angiotensin system. The first intervention trials indicate that vitamin D may suppress cardiovascular risk markers. However, more controlled clinical trials are needed to investigate whether optimal oral vitamin D supplementation is able to reduce CVD morbidity and mortality.

Interleukin-6 modulates plasma cholesterol and C-reactive protein concentrations in nonagenarians

OBJECTIVES

To establish whether the relationship between interleukin-6 (IL-6) and plasma lipid and C-reactive protein (CRP) concentrations is different in Finnish nonagenarians than in middle-aged subjects with lower inflammatory status.

DESIGN

Cross-sectional.

SETTING

Observational cohort study concentrating on the oldest old.

PARTICIPANTS

Nonagenarians (n=291, mean age+/-standard deviation 90+/-1; 68 men, 223 women) who lived in the Tampere municipality in southern Finland and a middle-aged control population from the same area (n=227, aged 44+/-8).

MEASUREMENTS

Plasma high sensitive CRP and lipid concentrations were analyzed using an automatic analyzer and IL-6 levels using enzyme-linked immunosorbent assay.

RESULTS

Plasma concentrations of IL-6 (4.39+/-5.25 vs 1.88+/-1.98 pg/mL) and CRP (3.54+/-4.98 vs 1.53+/-1.91 mg/L) were significantly higher in nonagenarians than in middle-aged subjects (P<.001). In nonagenarians, plasma CRP levels increased (P<.001) and plasma total cholesterol (P=.006), low-density lipoprotein cholesterol (P=.02), and high-density lipoprotein cholesterol (P=.002) levels decreased according to IL-6 quartiles. In middle-aged subjects, similar associations were not found.

CONCLUSION

The relationship between IL-6 and plasma CRP and cholesterol levels in nonagenarians with enhanced systemic inflammation differs from that of middle-aged subjects.

Plasma Levels of Mannan-Binding Lectin in Relation to Periodontitis and Smoking

BACKGROUND

Mannan-binding lectin (MBL) is an important molecule of innate immunity; it acts as an opsonin and stimulates the classical complement pathway. Moreover, it has been suggested that MBL acts as a weak acute phase protein. We investigated whether MBL levels are increased in periodontitis, and we tested whether individuals deficient for MBL are more susceptible to periodontitis.

METHODS

A total of 219 subjects participated in the study. Plasma samples from 115 periodontitis patients and 104 healthy controls were taken, and the MBL levels were measured by enzyme-linked immunosorbent assay (ELISA). MBL levels were analyzed in relation to periodontitis, taking into consideration age, gender, ethnic and educational background, and smoking status. In some analyses, subjects with MBL plasma levels <0.8 microg/ml were considered MBL deficient.

RESULTS

MBL plasma concentrations were not significantly different in moderate and severe periodontitis compared to controls (1.6, 1.4, and 1.6 microg/ml, respectively). Also, the prevalence of MBL deficiency was not found to be different between controls and moderate and severe periodontitis (45%, 37%, and 36%). However, among all subjects and among the non-deficient subjects, MBL levels were markedly increased in heavy smokers (>10 cigarettes per day), irrespective of periodontal disease status, in comparison to non-smokers and light smokers. MBL plasma levels did not show a correlation with plasma C-reactive protein (CRP) and were also not related to the prevalence of specific periodontal pathogens.

CONCLUSIONS

MBL levels were not elevated in periodontitis, and MBL deficiency was not related to susceptibility for periodontitis. The fact that MBL levels were higher among heavy smokers is the subject of further investigation.

C-Reactive Protein in Heart Failure

Background— The role of C-reactive protein (CRP) in heart failure is not well studied. We assessed the prognostic value of CRP in patients randomized in Val-HeFT (Valsartan Heart Failure Trial) and studied changes in CRP that were associated with valsartan.

Methods and Results— Characteristics of patients with baseline CRP levels above and below the median value were compared. Univariable and multivariable Cox proportional hazards regression models were used to examine the relationship of CRP to mortality and morbidity. Interactions were tested to determine whether differences in CRP changes from baseline to 4 and 12 months between groups randomly assigned to valsartan or placebo depended on baseline ACE inhibitor use. Median plasma CRP was 3.23 mg/L (interquartile range 1.42 to 7.56 mg/L), which is higher than in the general population. Patients with CRP above the median had features of more severe heart failure than those with CRP levels below the median. The cumulative likelihood of death and first morbid event increased with increasing quartile of CRP. Relative to the lowest CRP quartile, the risk of mortality (hazard ratio 1.51, 95% CI 1.2 to 1.9) and first morbid event (hazard ratio 1.53, 95% CI 1.28 to 1.84) was increased in the highest CRP quartile in multivariable models. CRP added incremental prognostic information to that provided by brain natriuretic peptide alone. CRP did not change significantly over time in the placebo group; however, after 12 months, valsartan was associated with a decrease in CRP in patients not receiving ACE inhibitors but not in those receiving ACE inhibitors at 12 months.

Conclusions— CRP is increased in heart failure. Higher levels are associated with features of more severe heart failure and are independently associated with mortality and morbidity. The ability of treatments to reduce CRP levels and the prognostic importance of reducing CRP require further study.

High-sensitive C-reactive protein, tumor necrosis factor alpha, and cardiovascular risk factors before and after weight loss in obese children

To confirm the existence of obesity-induced inflammation and to clarify the association between such inflammation and other cardiovascular risk factors, we investigated the relationships between high-sensitive C-reactive protein (hsCRP), tumor necrosis factor alpha (TNF-alpha), obesity, blood pressure, lipids, and insulin resistance in a long-term follow-up of obese children. We compared the serum concentrations of hsCRP, TNF-alpha, high-density lipoprotein cholesterol, and triglycerides as well as blood pressure and the insulin resistance index (homeostasis model assessment [HOMA]) of 14 nonobese and 31 obese children. Furthermore, we studied the changes in these parameters in 16 obese children who lost weight and in 15 obese children without weight change over a 1-year period. In the obese children, blood pressure (P=.003), HOMA (P=.034), and triglyceride (P=.011), TNF-alpha (P=.015), and hsCRP (P<.001) levels were significantly higher, whereas high-density lipoprotein cholesterol concentrations were significantly (P=.015) lower compared with the nonobese children. Weight loss was associated with a significant decrease in hsCRP (P=.008) and triglyceride (P=.048) levels, HOMA (P<.001), and blood pressure (P=.019), whereas there were no significant changes in the children with stable weight status. The changes in hsCRP and TNF-alpha levels over the 1-year period were not significantly correlated to the changes in lipids, blood pressure, and HOMA. Obese children demonstrated significantly higher levels of hsCRP and TNF-alpha compared with nonobese children. The chronic inflammation markers TNF-alpha and hsCRP were independent of lipids, blood pressure, and insulin resistance index. Weight loss was associated with the significant decrease of hsCRP and triglyceride levels, and blood pressure.

Potential role of ultrafine particles in associations between airborne particle mass and cardiovascular health

Numerous epidemiologic time-series studies have shown generally consistent associations of cardiovascular hospital admissions and mortality with outdoor air pollution, particularly mass concentrations of particulate matter (PM) < or = 2.5 or < or = 10 microm in diameter (PM2.5, PM10). Panel studies with repeated measures have supported the time-series results showing associations between PM and risk of cardiac ischemia and arrhythmias, increased blood pressure, decreased heart rate variability, and increased circulating markers of inflammation and thrombosis. The causal components driving the PM associations remain to be identified. Epidemiologic data using pollutant gases and particle characteristics such as particle number concentration and elemental carbon have provided indirect evidence that products of fossil fuel combustion are important. Ultrafine particles < 0.1 microm (UFPs) dominate particle number concentrations and surface area and are therefore capable of carrying large concentrations of adsorbed or condensed toxic air pollutants. It is likely that redox-active components in UFPs from fossil fuel combustion reach cardiovascular target sites. High UFP exposures may lead to systemic inflammation through oxidative stress responses to reactive oxygen species and thereby promote the progression of atherosclerosis and precipitate acute cardiovascular responses ranging from increased blood pressure to myocardial infarction. The next steps in epidemiologic research are to identify more clearly the putative PM casual components and size fractions linked to their sources. To advance this, we discuss in a companion article (Sioutas C, Delfino RJ, Singh M. 2005. Environ Health Perspect 113:947-955) the need for and methods of UFP exposure assessment.

Moderate alcohol consumption and lower levels of inflammatory markers in US men and women

OBJECTIVE

Moderate alcohol consumption is associated with substantially lower risk of cardiovascular disease (CVD). We assessed the relationship between alcohol intake and inflammatory markers to partially explain this beneficial effect.

METHODS AND RESULTS

From two large prospective studies, we sampled 959 healthy male and 473 healthy female health professionals with reported alcohol intake. Markers of inflammation were soluble tumor necrosis factor-alpha receptors 1 and 2 (sTNF-R1 and sTNF-R2), C-reactive protein (CRP), and interleukin-6 (IL-6). We found significant inverse linear trends for sTNF-R1 (p-trend<0.001 men; 0.03 women) and sTNF-R2 (p-trend=0.002 men; 0.08 women) with increasing alcohol intake. Compared to non-drinkers, men who consumed on average 1-2 drinks/day had 26% lower CRP (-0.66 mg/L, p=0.13), and 36% lower IL-6 (-1.12 pg/ml, p=0.02) levels. Among women, a similar though stronger association was observed at half drink per day. Compared to non-drinkers, both men and women who consumed 1-2 drinks/drinking day had significantly lower sTNF-R1 (-9% in men, -6% in women) and sTNF-R2 (-7% in men, -6% in women) levels as well as lower CRP (-10% in men, -32% in women) and IL-6 (-45% in men, -27% in women) levels.

CONCLUSIONS

Alcohol in moderation is associated with lower levels of inflammatory markers and may lower risk of CVD through these mechanisms.

Relation of high-sensitivity C-reactive protein, interleukin-6, tumor necrosis factor-alpha, and fibrinogen to abdominal adipose tissue, blood pressure, and cholesterol and triglyceride levels in healthy postmenopausal women

The associations of inflammatory markers (high-sensitivity C-reactive protein [hs-CRP], interleukin-6 [IL-6], tumor necrosis factor-alpha, and fibrinogen) with anthropometric and metabolic variables were examined in a sample of 112 postmenopausal women not receiving hormone therapy. Body fat distribution was measured by computed tomography, and insulin sensitivity was determined by an euglycemic-hyperinsulinemic clamp. hs-CRP (0.10 < or = r(2) < or =0.37) and IL-6 (0.06 < or = r(2) < or =0.31) were significantly associated with anthropometric and metabolic variables, including visceral and subcutaneous adipose tissue, systolic and diastolic blood pressure, triglycerides, high-density lipoprotein (HDL) cholesterol, and insulin sensitivity (p <0.05). Women with greater hs-CRP concentrations showed deterioration in their metabolic risk profiles, including abdominal obesity, greater triglyceride and lower HDL cholesterol concentrations, and lower insulin sensitivity compared with women with lower hs-CRP levels. Fifty-nine percent of women with high hs-CRP concentrations had the metabolic syndrome as recently defined by the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. After adjustment for visceral adipose tissue, most of the differences in the plasma lipid-lipoprotein profile were eliminated between women with high hs-CRP levels and women with low hs-CRP levels, whereas some differences in blood pressure variables, insulin sensitivity, and inflammatory markers (IL-6 and fibrinogen) remained significant. In conclusion, these results suggest that increased visceral adipose tissue levels appear to be a determinant covariable of the association between high hs-CRP concentrations and alteration in the metabolic profile.

Independent association between inflammatory markers (C-reactive protein, interleukin-6, and TNF-alpha) and essential hypertension

High blood pressure (HBP) has been associated with elevated C-reactive protein (CRP), a marker of chronic mild inflammation. However, the association between HBP and other inflammatory markers, particularly interleukin 6 (IL-6) and tumour necrosis alpha (TNF-alpha), has not been evaluated in well-controlled studies. We examined the cross-sectional relationship between IL-6, TNF-alpha, and CRP and HBP in a random sample of 196 healthy subjects. All markers were measured in duplicate with high-sensitivity ELISA tests. Three blood pressure (BP) measurments were averaged for the analysis, and subjects with systolic BP >or=140 and/or diastolic BP >or=90 mmHg were considered hypertensive. Log binomial regression was used to estimate multivariate-adjusted prevalence ratios (PR) of HBP. Of the subjects, 40% (79) were hypertensive (mean age: 44 years; range 30-64). After adjustment for age, sex, body mass index, family history of HBP, and the level of the other inflammatory markers, subjects in the second (PR: 3.10, P=0.003), third (PR: 2.32; P=0.031), and fourth quartiles (PR: 2.30; P=0.036) of IL-6 were more than twice as likely to be hypertensive than those in the first quartile. Corresponding PR estimates for TNF-alpha levels were 1.41 (P=0.014) for the second; 1.59 (P=0.001) for the third; and 1.61 (P=0.025) for the fourth quartile. The CRP-HBP association was not statistically significant. Our results suggest that TNF-alpha and IL-6 could be independent risk factors for HBP in apparently healthy subjects. Nevertheless, the temporal relationship between elevated inflammation markers and HBP should be ascertained in prospective cohort studies.

Dyslipidemia and inflammation: an evolutionary conserved mechanism

Inflammation leads to changes in lipid metabolism aimed at decreasing the toxicity of a variety of harmful agents and tissue repair by redistributing nutrients to cells involved in host defence. Acute phase response, mediated by cytokines, preserves the host from acute injury. When this inflammation becomes chronic, it might lead to chronic disorders as atherosclerosis and the metabolic syndrome. The activation of the inflammatory cascade will induce a decrease in HDL-cholesterol (HDL-C), with impairment in reverse cholesterol transport, and parallel changes in apolipoproteins, enzymes, anti-oxidant capacity and ATP binding cassette A1-dependent efflux. This decrease in HDL-C and phospholipids could stimulate compensatory changes, as synthesis and accumulation of phospholipid-rich VLDL which binds bacterial products and other toxic substances, resulting in hypertriglyceridemia. The final consequence is an increased accumulation of cholesterol in cells. When the compensatory response (inflammation) is not able to repair injury, it turns into a harmful reaction, and the lipid changes will become chronic, either by repeated or overwhelming stimulus, enhancing the formation of atherosclerotic lesions. Thus, the classical lipid changes associated with the metabolic syndrome (increased triglycerides and decreased HDL-C) may be envisioned as a highly conserved evolutionary response aimed at tissue repair. Under this assumption, the problem is not the response but the persistence of the stimulus.

Prevalence of Helicobacter pylori infection in male patients with osteoporosis and controls

Cytokines that regulate bone turnover (tumor necrosis factor-alpha, interleukin-6, etc.) may influence the pathogenesis of skeleton disorders, such as osteoporosis. Since Helicobacter pylori infection increases the systemic levels of inflammatory cytokines, we investigated the possibility that this infection increases the risk of developing osteoporosis and affects the bone metabolism in a group of male patients with osteoporosis. We examined 80 osteoporotic male patients and 160 controls for serum antibodies to H. pylori and the CagA protein and determined, in patients alone, the most important biochemical and instrumental parameters of the disease. Fifty-one patients (63.7%) and 107 controls (66.8%) were seropositive for H. pylori infection (nonsignificant); 30 infected patients (58.8%) and 43 infected controls (40.1%) were positive for anti-CagA antibodies (P = 0.028; OR = 2.13). Levels of estradiol in infected CagA-positive patients were significantly lower than in infected CagA-negative patients (28.5 [SD = 10.18] vs. 39.5 [SD = 14.50] pg/ml; P = 0.002) and uninfected patients (35.2 [SD = 12.7] pg/ml; P = 0.028). Levels of urinary cross-laps(a marker of bone resorption) were increased in patients infected by CagA-positive strains compared to patients infected by CagA-negative strains (282.9 [SD = 103.8] vs. 210.5 [SD = 150.1]microg/mmol; P = 0.048) and uninfected patients (204.3 [SD = 130.1] microg/mmol; P = 0.016). Differences among uninfected and infected patients, independent of CagA status, were observed for other markers of bone turnover, but they did not reach statistical significance. Infection by CagA-positive H. pylori strains is more prevalent in men with osteoporosis, who show reduced systemic levels of estrogens and increased bone turnover. H. pylori infection by strains expressing CagA may therefore be considered a risk factor for osteoporisis in men.

Serum total sialic acid levels in smokers and users of smokeless tobacco in form of oral powder (Maraş powder)

Smokeless tobacco (ST) is widely used as chewing tobacco and as oral snuff in the world. Also, in Kahramanmaraş, a city in Southern Turkey, ST used as 'oral powder' or 'Maraş Powder' is consumed widely instead of cigarette smoking. The aim of this study was to search the effect of ST use on serum total sialic acid (TSA) and to compare the serum TSA levels in smokers and ST users. The study was performed at the Department of Chemistry-Biochemistry, University of Kahramamaraş Sutcu Imam, Turkey, in 2003. Serum samples obtained from smokers (Group I), Maraş powder users (Group II), and healthy control subjects (Group III) who were nonsmokers and nonusers ST. Individuals who were smokers and ST users were classified into subgroups with respect to amount of consumed cigarette or oral powder. Serum TSA was measured with the Denny's colorimetric method. The TSA concentrations were significantly higher in the sera of smokers (p < 0.001) and Maraş powder users (p < 0.001) than those of control subjects. The mean serum TSA level was found to be lowest in the control group and highest in the Maraş Powder users. But, there was no significant difference in serum TSA levels between smokers and Maraş powder users (p > 0.05). We can conclude from the results obtained that serum TSA was affected by ST use as seen in smokers. This finding may be an indication of harmful effects of ST use as Maraş powder as well as cigarette smoking.

Active smoking and a history of smoking are associated with enhanced prostaglandin F(2alpha), interleukin-6 and F2-isoprostane formation in elderly men

The underlying mechanisms by which smoking induces cardiovascular diseases are largely unknown. The effect of smoking status on the cyclooxygenase (COX)-mediated inflammatory indicator prostaglandin F(2alpha) (PGF(2alpha)) has never been studied. Associations of cytokines and antioxidants and smoking status, have shown conflicting results. Urinary 15-keto-dihydro-PGF(2alpha) (a major metabolite of PGF(2alpha)), serum interleukin-6 (IL-6) and high sensitivity C-reactive protein (hsCRP), serum amyloid protein A (SAA), urinary 8-iso-PGF(2alpha) (an F(2)-isoprostane, indicator of oxidative stress), and serum alpha-tocopherol were quantified in a population-based sample (n = 642) of 77-year old men without diabetes. Fifty-five men were current smokers and 391 former smokers. Inflammatory indicators were increased in current smokers (15-keto-dihydro-PGF(2alpha), P < 0.001; IL-6, P = 0.01) than non-smokers. 8-iso-PGF(2alpha) was increased (P < 0.01) and alpha-tocopherol reduced (P < 0.001) in current smokers. Further, former smokers had increased formation of 15-keto-dihydro-PGF(2alpha), IL-6 and 8-iso-PGF(2alpha) compared non-smokers. This is the first study to show that smokers have increased PGF(2alpha) formation, thus enhanced COX-mediated inflammation, in addition to elevated levels of cytokines and isoprostanes. Subclinical COX- and cytokine-mediated inflammation and oxidative stress are ongoing processes not only in active smokers but also in former smokers which may contribute to the accelerated atherosclerosis associated with smoking.

Behavioural treatments for chronic systemic inflammation: effects of dietary weight loss and exercise training

Persistent low-grade inflammation, as indicated by higher circulating levels of inflammatory mediators such as C-reactive protein, interleukin-6 and tumour necrosis factor-alpha, is a strong risk factor for several chronic diseases. There are data indicating that decreasing energy intake and increasing physical activity may be effective therapies for reducing overall inflammation. Evidence is strong that circulating levels of inflammatory markers are elevated with total and abdominal obesity, possibly owing to a higher secretion rate of cytokines by adipose tissue in obese people. Moreover, very-low-energy dietary weight loss reduces both circulating markers of inflammation and adipose-tissue cytokine production. Data from several large population-based cohorts show an inverse association between markers of systemic inflammation and physical activity or fitness status; small-scale intervention studies support that exercise training diminishes inflammation. Dietary weight loss plus exercise is likely more effective than weight reduction alone in reducing inflammation. To date, data from randomized, controlled trails designed to definitively test the effects of weight loss or exercise training, or both, on inflammation are limited. Future studies are required to define the amount of weight loss needed for clinically meaningful reductions of inflammation; in addition, fully powered and controlled studies are necessary to clarify the effect of exercise training on chronic, systemic inflammation.

Helicobacter pylori eradication has no effect on metabolic and inflammatory parameters

BACKGROUND

An increased risk in coronary heart disease associated with Helicobacter pylori (H. pylon) appears to be partially mediated by modifications of the atherogenic lipoprotein and inflammatory parameters. We conducted a controlled trial aimed at evaluating the changes of metabolic and inflammatory parameters after H. pylon eradication.

METHODS

We included in the study 169 patients with H. pylori infection and conducted a retrospective longitudinal survey of 87 subjects (76 men, 11 women) who received treatment for H. pylon eradication and 82 control subjects (63 men, 19 women) who did not receive treatment. We compared pre- and posteradication (one year after) the metabolic and inflammatory parameters, such as blood sugar, lipid profiles, insulin resistance, white blood cell count and C-reactive protein.

RESULTS

No significant changes from the baseline in metabolic and inflammatory parameters within each group were observed. Changes in the serum levels of metabolic and inflammatory parameters were similar between the two groups.

CONCLUSIONS

Metabolic and inflammatory parameters, including blood sugar, lipid profiles, insulin resistance, white blood cell count and C-reactive protein, were not changed after H. pylori eradication treatment. H. pylori eradication has no effect on metabolic and inflammatory parameters.

The effects of peritoneal dialysis and hemodialysis on serum tumor necrosis factor-alpha, interleukin-6, interleukin-10 and C-reactive-protein levels

BACKGROUND

Markers of an acute phase reaction, such as C-reactive protein (CRP) or tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6, are predictive for cardiovascular morbidity and mortality in normal subjects and in chronic renal failure patients. In this study, we aimed to investigate serum TNF-alpha, IL-6, IL-10 and CRP levels in continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD) patients.

MATERIALS AND METHODS

Serum levels of TNF-alpha, IL-6, IL-10 and CRP levels were measured in 30 patients who were just diagnosed with end-stage renal failure and treated, with 16 CAPD (nine female, seven male) and 14 HD (eight female, six male) patients, before CAPD or HD treatment and after 3 months from the beginning of CAPD or HD in patients with no clinical signs of infection. The control groups were 20 healthy persons of similar age and sex. Serum levels of TNF-alpha, IL-6, IL-10 and CRP were measured by enzyme-linked immunosorbent assay in stable CAPD and HD patients and in healthy persons.

RESULTS

The mean serum levels of TNF-alpha, IL-6, IL-10 and CRP showed no significant differences between the CAPD and HD patients for the beginning values and the third month of treatment. However, serum TNF-alpha, IL-6, IL-10 and CRP levels were higher than the control group in the CAPD and HD patients regarding the beginning values and the third month of treatment (p < 0.001).

CONCLUSIONS

CAPD and HD of the renal replacement therapy have no effects on serum CRP and cytokines.

High throughput mRNA profiling highlights associations between myocardial infarction and aberrant expression of inflammatory molecules in blood cells

Studies on the role of inflammation in cardiovascular disease focus on surrogate markers like plasma levels of C-reactive protein or interleukins that are affected by several factors. In this study we employ an approach in which the inflammatory mRNA profile of leucocytes is measured directly in a multigene system. We investigated the mRNA profile for 35 inflammatory markers in blood samples in a case-control study including 524 men with a history of myocardial infarction and 628 control subjects. Compared with controls, patients showed mRNA profiles with increased levels of most inflammatory mRNAs. The 2 most prominent mRNA risk indicators encoded the secreted protein macrophage migration inhibitory factor (crude odds ratio [OR], 3.4 for the highest quartile versus the lowest quartile (95% confidence interval [CI95], 2.3-4.9), and the intracellular regulator proteinase inhibitor 9 (OR, 2.5 for the highest versus the lowest quartile (CI95, 1.8-3.5), both showing an increase in odds ratio with increasing quartiles. Leucocytes in the blood of patients with myocardial infarction are more active in transcription of inflammatory genes, as evidenced by mRNA profiling. These data support the hypothesis that an inflammatory response involving leucocytes plays a role in the pathogenesis of myocardial infarction.

The association between interleukin-6, sleep, and demographic characteristics

We examined the relationship between the pro-inflammatory cytokine IL-6 and sleep architecture in 70 healthy men and women. Blood was drawn in the early morning for assessment of IL-6 followed by nocturnal sleep monitoring with polysomnography. Sleep records were scored for sleep stages using standard criteria. Morning IL-6 levels were positively correlated with REM latency after sleep onset [rho = .31, p = .01], percent (%) stage 1 sleep [rho = .23, p = .053], % wake after sleep onset (WASO) [rho = .29, p<.05]. IL-6 levels were negatively correlated with sleep efficiency [rho = -.36, p<.01] and slow wave sleep (SWS) [rho = -.26, p<.05]. After controlling for demographic variables including race, gender, age, and BMI, multiple hierarchical regression analyses revealed that morning IL-6 levels accounted for a significant portion of the variance of REM latency (p<.01), sleep efficiency (p<.01), and % WASO (p = .01). IL-6 was no longer associated with % stage 1 sleep, SWS, and total sleep time after controlling for the demographic characteristics. These findings suggest that the inflammatory marker IL-6 is associated with sleep quality and that certain individual characteristics such as race, gender, and age modify that relationship. Higher IL-6 levels were associated with lower quality of sleep among healthy asymptomatic men and women.

Lifestyle-only intervention attenuates the inflammatory state associated with obesity: a randomized controlled study in adolescents

OBJECTIVES

The primary goals were to understand the relationship among the inflammatory factors, C-reactive protein (CRP), interleukin-6 (IL-6), and fibrinogen, and indices of obesity in normoglycemic, insulin-resistant adolescents and to investigate the impact of a lifestyle-only intervention on these nontraditional risk factors for cardiovascular disease (CVD).

STUDY DESIGN

Randomized controlled lifestyle-only intervention study in adolescents. Of the 21 adolescents studied, 15 obese subjects (body mass index [BMI] = 37.6 +/- 3.3 kg/m 2 ) were randomized to either a lifestyle intervention program or usual care. The lean controls were studied only at baseline. Analysis of variance (ANOVA) for repeated measures was used to study intervention effect and t test, one-way ANOVA, and discriminant function analysis for baseline comparisons.

RESULTS

The intervention group maintained weight, whereas the control group gained weight (P = .02). A redistribution of body composition and a decrease in insulin resistance were observed. Elevated circulating concentrations of CRP, fibrinogen, and IL-6 were significantly reduced (all P <or=.02) in response to intervention, but not in controls.

CONCLUSIONS

Modest lifestyle-only change in previously sedentary obese adolescents redistributes the parameters of body composition in the absence of weight loss and reverses, at least in part, the inflammatory state in association with an improvement of insulin resistance.

Proinflammatory parameters as CRP and IL-6 do not discriminate between post-PCI cardiac patients with and without exercise-induced ischemia as indicated by Tl-201 myocardial scintigraphy

INTRODUCTION

Atherosclerosis is looked upon as an inflammatory disease. The production of proinflammatory markers may indicate activity in this inflammatory state.

METHODS

We prospectively evaluated a range of proinflammatory serum parameters in 136 cardiac patients who had previously undergone percutaneous coronary intervention (PCI).

RESULTS

By means of myocardial scintigraphy, an ischemia group (A; n=49) and a group with stable cardiovascular disease without exercise induced ischemia (B; n=87) were distinguished. Risk factors and lipoprotein profile of both groups were comparable. Serum levels of serum C-reactive protein (CRP), IL-6, sTNF-RI, IGF-I, neopterin, serotonin and prolactin did not present any significant difference between the two groups.

CONCLUSIONS

We conclude that measurement of these (inflammatory) parameters does not help to delineate post-PCI cardiac patients with and without exercise-induced ischemia.

Biological variations, genetic polymorphisms and familial resemblance of TNF-α and IL-6 concentrations: STANISLAS cohort

Cytokines are involved in the development of several inflammatory diseases and atherosclerosis. Their variations in healthy individuals are not well defined. The aims of this study were: firstly, to identify factors affecting biological variation of interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha); secondly, to study their family resemblance; and thirdly, to evaluate the effect of two TNF-alpha (-308G/A and -238G/A) and two IL-6 polymorphisms (174G/C and -572G/C) on their corresponding circulating levels. A total of 171 healthy families selected from the STANISLAS cohort were studied. Age was negatively related to TNF-alpha concentrations in offspring only (both sons and daughters). Additionally, IL-6 and TNF-alpha levels were differently influenced by gender, white blood cells, tobacco consumption, and HDL-cholesterol level. A weak significant familial resemblance for TNF-alpha concentration was observed in siblings only. There was no significant familial resemblance for IL-6 levels. The TNF-alpha -308A allele was associated with decreased TNF-alpha concentrations in both offspring aged less than 18 and males without overweight (BMI<25 kg/m(2)). Fathers carrying the IL-6 -174CC genotype had higher IL-6 levels than those with the IL-6 -174G allele. Parents with the IL-6 -572GG genotype had higher IL-6 concentrations than the C allele carriers. In this sample of healthy families, plasma levels of IL-6 and TNF-alpha were differently affected by biological parameters including age, gender and smoking, and the impact of their respective polymorphisms was influenced by gender, age and BMI.

Elevated C-reactive protein levels in the development of type 1 diabetes

Elevated C-reactive protein (CRP) levels have previously been described before the onset of type 2 diabetes and gestational diabetes. We hypothesized that inflammation, as reflected by elevated CRP levels, can help predict development of islet autoimmunity or type 1 diabetes. Children at risk for type 1 diabetes and followed in the Diabetes Autoimmunity Study of the Young (DAISY) had blood samples drawn and frozen serum saved at various intervals after birth. CRP was measured using a high-sensitivity sandwich enzyme immunoassay. Islet autoantibodies (IAs) were measured using biochemical immunoassays. Elevations in CRP concentrations were significantly more frequent (P < 0.01) in children who later developed type 1 diabetes (8 of 16 children) than in children negative for IAs at their last testing (3 of 26). Children with one or more positive IA were more likely to have elevated CRP concentrations (15 of 36) than IA-negative children (3 of 26; P < 0.01). The finding of elevated CRP levels in infants and young children before the onset of type 1 diabetes adds to the evidence that the disease is an immunoinflammatory disorder. The elevated CRP levels may provide an additional marker for risk of progression to type 1 diabetes.

Enhanced expression of cytokines and chemokines by blood monocytes to in vitro lipopolysaccharide stimulation are associated with hostility and severity of depressive symptoms in healthy women

The current study investigated the relation of hostility and severity of depressive symptoms, separately and jointly, to the capacity of blood monocytes to secrete an array of cytokines when stimulated by bacterial lipopolysaccharide (LPS). Subjects were 44 healthy, non-smoking, premenopausal women (aged 23-49 years) not currently taking oral contraceptives. Data were collected during the follicular phase of the menstrual cycle. The Cook-Medley Hostility (Ho) scale and the Beck Depression Inventory (BDI) were used to assess hostility and severity of depressive symptoms, respectively. Dual-color flow cytometry was used to measure the total expression of interleukin (IL)-1alpha, IL-1beta, IL-8, tumor necrosis factor (TNF)-alpha, monocyte chemotactic protein (MCP)-1 and monocyte inflammatory protein (MIP)-1alpha in blood monocytes following 4 h in vitro LPS stimulation of whole blood. In analyses adjusting for age, body mass index (BMI), fasting cholesterol, alcohol use, race and 17beta-estradiol (E(2)), higher Ho scores were associated with greater LPS-stimulated expression of IL-1alpha (beta = 0.033, p = 0.02), IL-8 (beta = 0.046, p = 0.01) and IL-1beta (beta = 0.024, p = 0.06). Higher BDI scores were associated with greater expression of TNF-alpha (beta = 0.042, p = 0.02) and IL-8 (beta = 0.045, p = 0.04). The linear combination of Ho and BDI scores was significantly associated with IL-1beta (beta = 0.18, p = 0.057), IL-8 (beta = 0.36, p = 0.01), TNF-alpha (beta = 0.25, p = 0.03), and IL-1alpha (beta = 0.18, p < 0.07). Thus, in healthy women, these psychological risk factors, alone and in combination, induce a proinflammatory phenotype in circulating monocytes characterized by the up-regulation of proinflammatory cytokines, supporting the hypothesis that inflammation may be a key pathway whereby hostility and depressive symptoms contribute to atherosclerosis and subsequent coronary heart disease (CHD).

Body fat is the main predictor of fibrinogen levels in healthy non-obese men

Previous studies have demonstrated that circulating levels of C-reactive protein (CRP), a marker of cardiovascular risk, are strictly related to body fatness. Elevated fibrinogen levels are also predictive of future cardiovascular events. The metabolic background of this relationship and the predictors of fibrinogen levels have not been well established. We aimed to evaluate whether fibrinogen levels are associated with body fat content and distribution and to determine the independent predictors of fibrinogen levels in a sample of healthy, non-obese, nonsmoking young adult men. Age, anthropometric measures (body mass index [BMI], waist-to-hip ratio [WHR]), total and regional fat content (determined by dual x-ray absorptiometry [DXA]), metabolic variables (total cholesterol [T-Chol], low-density lipoprotein cholesterol [LDL-C], and high-density lipoprotein cholesterol [HDL-C]; triglycerides [TG]; glucose and insulin levels; fasting insulin resistance index [FIRI]; blood pressure), interleukin-6 (IL-6), and acute-phase reactants levels (fibrinogen, highly sensitive [hs]-CRP) were determined in 87 healthy nonsmoking, non-obese subjects. Linear regression analysis was used to evaluate the association between body fat, fibrinogen, and metabolic variables, and multiple regression model analysis was used to examine the independent predictors of fibrinogen levels. Eighty-seven (30.5 +/- 3.5 years) non-obese (mean BMI 24.1 +/- 3.5) men were studied. Fibrinogen levels were strongly associated with measures of body fat and with metabolic variables. Total body fat (P < .0001) and LDL-cholesterol (P < .01) were the independent predictors of fibrinogen levels, accounting for 29.5% and 10.9% of its variance, respectively. Total body fat was the best independent predictor of hs-CRP levels, accounting for 32.5 % of its variance. We conclude that in healthy, non-obese subjects, body fat content is the main predictor of fibrinogen levels, as well of hs-CRP levels. These findings support the speculation that there is a direct mechanism by which adipose tissue might regulate the levels of circulating acute-phase reactants.

Beyond insulin resistance in NASH: TNF-alpha or adiponectin?

Adiponectin has antilipogenic and anti-inflammatory effects, while tumor necrosis factor alpha (TNF-alpha) reduces insulin sensitivity and has proinflammatory effects. We examined (1) the extent to which hypoadiponectinemia and TNF-alpha activation are features of nonalcoholic steatohepatitis (NASH) and (2) whether serum levels of these markers correlate with the severity of histological changes in 109 subjects with nonalcoholic fatty liver disease (NAFLD), including 80 with NASH and 29 with simple steatosis. By multivariate analysis, subjects with NASH had reduced adiponectin level and increased TNF-alpha and soluble TNF receptor 2 (sTNFR2)-but not leptin levels, compared with controls matched by age, sex, and body mass index; these differences were independent of the increased insulin resistance (by homeostasis model [HOMA-IR]) in NASH. When compared with simple steatosis, NASH was associated with lower adiponectin levels and higher HOMA-IR, but there were no significant differences in the levels of TNF-alpha and sTNFR2. The majority of subjects with steatohepatitis (77%) had adiponectin levels less than 10 microg/mL and HOMA-IR greater than 3 units, but only 33% of those with pure steatosis had these findings. HOMA-IR and low serum adiponectin were also independently associated with increased grades of hepatic necroinflammation. In conclusion, hypoadiponectinemia is a feature of NASH independent of insulin resistance. Reduced adiponectin level is associated with more extensive necroinflammation and may contribute to the development of necroinflammatory forms of NAFLD.

Bowel inflammation as measured by fecal calprotectin: a link between lifestyle factors and colorectal cancer risk

The mechanisms by which the lifestyle risk factors obesity, physical inactivity, and low fiber intake predispose to colorectal cancer (CRC) are unclear. Chronic bowel inflammation predisposes to malignancy in cases of inflammatory bowel disease. Many lifestyle risk factors for CRC are associated with evidence of systemic inflammation as indicated by circulating levels of C-reactive protein (CRP), but it is unknown how this relates to inflammation at tissue level. Little is known about the degree of bowel inflammation in general population and the factors that affect it. Therefore, we aimed to assess the relation of levels of bowel inflammation in the general population and lifestyle risk factors for CRC, and to additionally assess whether these associations, if present, were attenuated by controlling for evidence of systemic inflammation. Average CRC risk subjects (320) of either sex aged 50-70 were recruited in South London. A stool sample was provided for calprotectin measurement (a marker of bowel inflammation), serum for CRP, and a detailed dietary and lifestyle questionnaire completed. There was a significant positive relationship between fecal calprotectin and increasing age (P = 0.002), obesity (P = 0.04), physical inactivity (P = 0.01), and an inverse relationship with fiber intake (P = 0.02) and vegetable consumption (P = 0.04). The relationship with obesity was attenuated by controlling for serum CRP. Fecal calprotectin levels are associated with lifestyle risk factors for colorectal cancer. Low-level asymptomatic bowel inflammation may be the link between lifestyle and the pathogenesis of CRC, and circulating proinflammatory cytokines may be part of the mechanism for this link.

The pathophysiology of cigarette smoking and cardiovascular disease: an update

Cigarette smoking (CS) continues to be a major health hazard, and it contributes significantly to cardiovascular morbidity and mortality. Cigarette smoking impacts all phases of atherosclerosis from endothelial dysfunction to acute clinical events, the latter being largely thrombotic. Both active and passive (environmental) cigarette smoke exposure predispose to cardiovascular events. Whether there is a distinct direct dose-dependent correlation between cigarette smoke exposure and risk is debatable, as some recent experimental clinical studies have shown a non-linear relation to cigarette smoke exposure. The exact toxic components of cigarette smoke and the mechanisms involved in CS-related cardiovascular dysfunction are largely unknown, but CS increases inflammation, thrombosis, and oxidation of low-density lipoprotein cholesterol. Recent experimental and clinical data support the hypothesis that cigarette smoke exposure increases oxidative stress as a potential mechanism for initiating cardiovascular dysfunction.

Socioeconomic status and stress-induced increases in interleukin-6

Coronary artery disease (CAD) is more prevalent in people from a low socioeconomic background, and low socioeconomic status (SES) is associated with an increased exposure to psychological stress. The pro-inflammatory cytokine interleukin-6 (IL-6) plays a central role in CAD development. IL-6 is responsive to psychological stress and could potentially mediate the effect of psychosocial factors on CAD risk. Accordingly, we predicted that people of low SES would have greater and/or more sustained IL-6 responses to acute psychological stress. Based on previous findings, we also predicted that these people would have delayed post-stress cardiovascular recovery. Thirty-eight male civil servants were tested, with participants divided into high and low SES groups according to employment grade. There were no differences between the groups at baseline. However there were significant differences in IL-6 and heart rate responses to stress. Stress induced increases in plasma IL-6 in all participants. However, in the low SES group, IL-6 continued to increase between 75 min and 2h post-stress, whereas IL-6 levels stabilised at 75 min in the high SES group. Heart rate increased to the same extent following stress in both groups, however by 2h post-stress, it had returned to baseline in 75% of the high SES group compared with only 38.1% of the low SES group. These results suggest that low SES people are less able to adapt to stress than their high SES counterparts. Prolonged stress-induced increases in IL-6 in low SES groups represents a novel mechanism potentially linking socioeconomic position and heart disease.

Is alcohol anti-inflammatory in the context of coronary heart disease?

Although the cardioprotective effect of alcohol has been primarily explained by its effect on blood lipids and platelets, could an anti-inflammatory mechanism be involved?

Body fat and C-reactive protein levels in healthy non-obese men

BACKGROUND AND AIM

The relationships between C-reactive protein (CRP) levels, adipose tissue and metabolic alterations have not been clearly established in healthy non-obese subjects. We investigated the relationships between body fat, CRP levels and metabolic variables in healthy, non-obese sons of patients affected by metabolic syndrome (MS).

METHODS AND RESULTS

Age, CRP and interleukin 6 (IL-6) levels, anthropometric measures (body mass index, BMI; waist circumference and waist-to-hip ratio, WHR), total and regional fat content (as determined by means of dual X-ray absorptiometry, DXA), total and LDL cholesterol, and the metabolic variables related to MS (HDL-cholesterol, triglyceride, glucose and insulin levels; the fasting insulin resistance index, FIRI; blood pressure) were evaluated in 85 healthy non-obese sons of MS patients. Linear and multiple regression analyses were used to evaluate the relationships between body fat, metabolic variables and CRP levels, and to investigate whether the association between body fat content and metabolic variables persists after adjustment for CRP levels. Body fat was associated with all of the investigated variables. CRP levels were associated with total and regional body fat, the anthropometric index of weight, age, and with some metabolic alterations (HDL-cholesterol and triglyceride levels, systolic blood pressure, and fasting insulin and LDL-cholesterol levels). The associations between total body fat and the metabolic variables did not change after adjustment for CRP levels. Total body fat was the best predictor of CRP levels (p<0.0001).

CONCLUSIONS

In healthy, non-obese sons of MS patients, total body fat is the best predictor of CRP levels, and remains closely associated with metabolic abnormalities after adjustment for CRP levels. These findings strongly support the hypothesis that body fat is the main determinant of metabolic abnormalities and a low inflammatory state, at least in healthy subjects.

Helicobacter pylori seropositivity and atherosclerosis risk factors

Certain viral and bacterial infections may contribute to the initiation and progression of atherosclerosis. The aim of this study is to determine whether Helicobacter pylori (HP) seropositivity contributes to conventional atherosclerosis risk factors in the development of an early sign of atherosclerosis: intima-media thickness (IMT) of the carotid artery. Eighty-four patients who had at least two conventional atherosclerosis risk factors and a control group of 50 patients having no risk factors for atherosclerosis were enrolled in the study. None of the patients had ever received HP eradication treatment. HP IgG antibodies were determined by enzyme-linked immunosorbent assay. Carotid artery IMT was measured 1 cm before the carotid bifurcation. Seventy-five percent of the study group was HP seropositive. HP seropositive (n=64) and seronegative (n=21) groups were identical in terms of sex distribution, smoking pattern, mean age, hemoglobin, leukocyte, platelet, C-reactive protein, erythrocyte sedimentation rate, glucose, cholesterol, triglyceride, low-density lipoprotein, high-density lipoprotein, systolic blood pressure and diastolic blood pressure levels. There was no significant difference between the mean carotid IMT of HP seropositive (0.8+/-0.3 mm) and negative (0.8+/-0.3 mm) patients in the study group. Similar to the study group, there was no statistically significant difference between mean carotid IMT of HP seropositive (0.56+/-0.19 mm) and negative patients (0.67+/-0.13 mm) in the control group (p=0.2). Future studies concerning virulent strains are needed to determine the probable role of HP in atherosclerosis.

Association of markers of systemic inflammation, C reactive protein, serum amyloid A, and fibrinogen, with socioeconomic status

STUDY OBJECTIVE

Systemic inflammation may play an important part in the development of cardiovascular disease. It has also been shown that socioeconomic status predicts cardiovascular events independently of established risk factors. The aim of this study was to analyse the association of three sensitive markers of systemic inflammation: C reactive protein (CRP), serum amyloid A protein (SAA), and fibrinogen, with socioeconomic status.

DESIGN

Cross sectional study.

SETTING

Eastern and southern Finland.

PARTICIPANTS

1503 men aged 45 to 74 years who participated in a cardiovascular risk factor survey in 1997. Based on the levels of education and family income, the men were classified to three socioeconomic groups.

MAIN RESULTS

Mean concentrations of CRP (p for the trend <0.001), SAA (p for the trend 0.018), and fibrinogen (p for the trend <0.001) decreased substantially with increasing socioeconomic status. The trends in CRP and fibrinogen remained statistically significant after adjustment for smoking, waist to hip ratio, and prevalent longstanding diseases, and a non-significant trend was found for SAA (p for the trend 0.118). The inverse association between inflammation markers and socioeconomic status was particularly strong among the men below 60 years of age.

CONCLUSIONS

Systemic inflammation is a potential mediator, especially among young and middle aged men, for the association between socioeconomic status and cardiovascular disease.

Inflammatory markers and cardiovascular disease (The Health, Aging and Body Composition [Health ABC] Study)

This study investigates the association of several inflammatory markers with subclinical and clinical cardiovascular disease in older men and women. Data are from the baseline assessment of 3,045 well-functioning persons aged 70 to 79 years, participating in the Health, Aging and Body Composition study. The study sample was divided into 3 groups: "cardiovascular disease" (diagnosis of congestive heart failure, coronary artery disease, peripheral artery disease, or stroke), "subclinical cardiovascular disease" (positive findings on the Rose questionnaire for angina or claudication, ankle-brachial index <0.9, or electrocardiographic abnormalities), and "no cardiovascular disease." Serum levels of interleukin (IL)-6, C-reactive protein (CRP), tumor necrosis factor (TNF)-alpha, and the soluble receptors IL-6 soluble receptor, IL-2 soluble receptor, TNF soluble receptor I, and TNF soluble receptor II were assessed. Of those with IL-6 levels in the highest compared with the lowest tertile, the odds ratio (OR) for subclinical cardiovascular disease was 1.58 (95% confidence interval [CI] 1.26 to 1.97) and for clinical cardiovascular disease was 2.35 (95% CI 1.79 to 3.09). A similar association was found for TNF-alpha (OR 1.48, 95% CI 1.16 to 1.88 and OR 2.05, 95% CI 1.55 to 2.72, respectively). In adjusted analyses, CRP was not significantly associated with overall subclinical or clinical cardiovascular disease, although additional analyses did find a strong specific association between CRP and congestive heart failure (OR 1.64, 95% CI 1.11 to 2.41). Of the soluble cytokine receptors, only TNF soluble receptor I showed a significant association with clinical cardiovascular disease. Thus, our findings suggest an important role for IL-6 and TNF-alpha in clinical as well as subclinical cardiovascular disease. In this study, CRP had a weaker association with cardiovascular disease than the cytokines.

The associations between physical activity and inflammatory markers in high-functioning older persons: MacArthur Studies of Successful Aging

OBJECTIVES

To determine the relationships between recreational activity, house/yard work activity, work activity, and total physical activity and high levels of two peripheral blood markers of inflammation: interleukin-6 (IL-6) and C-reactive protein (CRP).

DESIGN

Cross-sectional study.

SETTING

Three communities (Durham, NC; New Haven, CT; and East Boston, MA).

PARTICIPANTS

Eight hundred seventy persons aged 70 to 79 who were in the top third of community-dwelling older persons with respect to physical and cognitive functioning.

MEASUREMENTS

Blood levels of IL-6 and CRP and self-reported recreational activity, house/yard work activity, work activity, and total physical activity.

RESULTS

The adjusted odds ratios (AORs) for individuals with high levels of recreational activity to have values in the top tertiles of IL-6 and CRP were 0.65 (95% confidence interval (CI) = 0.48-0.87) and 0.70 (95% CI = 0.51-0.95), respectively. The AORs for those with a high level of house/yard work activity to have values in the top tertile of IL-6 and CRP were 0.90 (95% CI = 0.67-1.20) and 0.70 (95% CI = 0.50-0.96), respectively. High levels of house/yard work and recreational activity were independently associated with lower risk of high CRP.

CONCLUSION

The association between high levels of recreational activity and lower levels of the inflammatory markers IL-6 and CRP suggests a mechanism for its protective effect and supports interventions that increase physical activity in older persons. Such potential benefits of increased physical activity on inflammatory markers will need to be confirmed in clinical trials.

Vascular risk factors and markers of endothelial function as determinants of inflammatory markers in type 1 diabetes: the EURODIAB Prospective Complications Study

OBJECTIVE

Inflammatory activity is increased in type 1 diabetes and may predispose to vascular disease. Its origin is not clear. We therefore investigated determinants of inflammation in type 1 diabetes.

RESEARCH DESIGN AND METHODS

We performed a nested case-control study from the EURODIAB Prospective Complications Study of 543 European individuals having type 1 diabetes (278 men), diagnosed at <36 years of age. Case subjects (n = 348) were those with one or more complications of diabetes; control subjects (n = 195) were all those with no evidence of any complication. We determined levels of C-reactive protein, interleukin-6, and tumor necrosis factor-alpha, combined them in a "general score of inflammatory markers," and investigated their associations with vascular risk factors and markers of endothelial dysfunction by use of multiple linear regression analysis.

RESULTS

Measures of inflammation were associated with sex, diabetes duration, glycemic control, the advanced glycation end product pentosidine, BMI, HDL cholesterol, triglycerides, and systolic blood pressure (standardized betas with the general score of inflammatory markers 0.15 [P = 0.002], 0.15 [P = 0.006], 0.18 [P < 0.0001], 0.12 [P = 0.005], 0.10 [P = 0.057], -0.15 [P = 0.001], 0.16 [P < 0.0001], and 0.09 [P = 0.042], respectively). In addition, measures of inflammation were strongly associated with markers of endothelial dysfunction, soluble vascular cell adhesion molecule-1, and soluble E-selectin (standardized betas with the general score of inflammatory markers 0.28 [P < 0.0001] and 0.19 [P < 0.0001]).

CONCLUSIONS

We have shown that conventional risk factors for vascular disease and endothelial adhesion molecules are important determinants of inflammation in type 1 diabetic individuals, suggesting that strategies to decrease inflammatory activity in type 1 diabetes should focus not only on control of conventional risk factors, but also on improvement of endothelial function.

The relation of severity of depressive symptoms to monocyte-associated proinflammatory cytokines and chemokines in apparently healthy men

OBJECTIVE

We examined the relation of severity of depressive symptoms to lipopolysaccharide-stimulated expression of monocyte-associated proinflammatory cytokines and chemokines in 53 nonsmoking, healthy men.

METHODS

Assessments of cytokine and chemokine expression and severity of depressive symptoms were conducted on the same day. The 21-item Beck Depression Inventory (BDI) was used to assess severity of depressive symptoms experienced during the week before study participation. Dual-color flow cytometry was used to determine monocyte-associated (CD14+) expression of interleukin-1alpha (IL-1alpha), IL-1beta, tumor necrosis factor-alpha (TNF-alpha), IL-8, and monocyte chemotactic protein-1 (MCP-1) after in vitro lipopolysaccharide stimulation of undiluted whole blood.

RESULTS

Calculations of partial correlation coefficients controlling for age, race, body mass index, and alcohol use indicated that BDI score was significantly associated with IL-1alpha (r = 0.27), IL-1beta (r = 0.44), TNF-alpha (r = 0.57), MCP-1 (r = 0.52), and IL-8 (r = 0.33). In addition, relative to men with BDI scores below 10, men with BDI scores of 10 or above exhibited an overexpression of IL-1beta (p =.004), TNF-alpha (p =.005), IL-8 (p =.002), and MCP-1 (p =.025).

CONCLUSIONS

Relative to men with no or minimal symptoms of depression, men with mild to moderate levels of depressive symptoms showed overexpression of monocyte-associated proinflammatory cytokines and chemokines.

Vitamin D in preventive medicine: are we ignoring the evidence?

Vitamin D is metabolised by a hepatic 25-hydroxylase into 25-hydroxyvitamin D (25(OH)D) and by a renal 1alpha-hydroxylase into the vitamin D hormone calcitriol. Calcitriol receptors are present in more than thirty different tissues. Apart from the kidney, several tissues also possess the enzyme 1alpha-hydroxylase, which is able to use circulating 25(OH)D as a substrate. Serum levels of 25(OH)D are the best indicator to assess vitamin D deficiency, insufficiency, hypovitaminosis, adequacy, and toxicity. European children and young adults often have circulating 25(OH)D levels in the insufficiency range during wintertime. Elderly subjects have mean 25(OH)D levels in the insufficiency range throughout the year. In institutionalized subjects 25(OH)D levels are often in the deficiency range. There is now general agreement that a low vitamin D status is involved in the pathogenesis of osteoporosis. Moreover, vitamin D insufficiency can lead to a disturbed muscle function. Epidemiological data also indicate a low vitamin D status in tuberculosis, rheumatoid arthritis, multiple sclerosis, inflammatory bowel diseases, hypertension, and specific types of cancer. Some intervention trials have demonstrated that supplementation with vitamin D or its metabolites is able: (i) to reduce blood pressure in hypertensive patients; (ii) to improve blood glucose levels in diabetics; (iii) to improve symptoms of rheumatoid arthritis and multiple sclerosis. The oral dose necessary to achieve adequate serum 25(OH)D levels is probably much higher than the current recommendations of 5-15 microg/d.

Inflammation, endothelial dysfunction, and the risk of high blood pressure: epidemiologic and biological evidence

In spite of its high impact on cardiovascular and renal disease, knowledge on risk factors for the development of high blood pressure (HBP) is limited. Mild chronic inflammation may play a significant role in the incidence of HBP. A persistent low-grade inflammation state could be associated with high but within the 'normal range' cytokine plasma concentration. By impairing the capacity of the endothelium to generate vasodilating factors, particularly nitric oxide (NO), elevated cytokines may lead to the development of endothelial dysfunction, chronic impaired vasodilation, and HBP. These alterations in the L-arginine : NO pathway may play a major role in the development of HBP in young subjects, with inflammation-related alterations in the production of cyclo-oxygenase-derived vasoconstrictors becoming more prominent with advanced age. Cross-sectional independent associations between HBP and plasma levels of C-reactive protein, interleukin-6, and tissue necrosis factor alpha have been reported, but no prospective evidence of these associations is currently available.

A polymorphism in the promoter of the tumor necrosis factor-alpha gene (-308) is associated with coronary heart disease in type 2 diabetic patients

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) is a key cytokine in the inflammation process of atherosclerosis. Through its effects on lipid metabolism, insulin resistance and endothelial function, it might be involved in coronary heart disease (CHD). A biallelic polymorphism within the promoter of TNF-alpha locus at the position -308 has been reported to be associated with TNF production. We have studied the association of this polymorphism with CHD in a Mediterranean non-diabetic and type 2 diabetic population.

METHODS

Three hundred and forty one CHD patients (106 with type 2 diabetes), 207 healthy matched control subjects and 135 type 2 diabetic patients without CHD were evaluated. A single nucleotide polymorphism at the promoter TNF-alpha (-308) was analyzed by RFLP-PCR.

RESULTS

TNF-alpha (-308) genotype and allele frequencies for A carriers were higher in CHD patients than those observed in the control group (32.3 vs. 23.2%, P=0.03; and 18.8 vs. 12.1%, P=0.0047; respectively) independently of other risk factors. Genotypic analysis revealed that CHD patients with type 2 DM displayed a greater prevalence of the -308 TNF-alpha A allele (40.6%) than controls (23.2%) or CHD patients without type 2 DM (28.5%) (P=0.0056). The odds ratio for CHD in type 2 diabetic patients in presence of -308 TNF-alpha A allele was 2.86 (CI 95%: 1.55-5.32). This difference was observed mainly in diabetic women for the A allele carriers (OR: 4.29; CI 95%: 1.6-11.76).

CONCLUSIONS

These results suggest that -308 TNF-alpha gene polymorphism may contribute to CHD risk in patients with type 2 diabetes and it could constitute an useful predictive marker for CHD in type 2 diabetic women.

Effect of a multidisciplinary program of weight reduction on endothelial functions in obese women

Obesity is associated with an increased risk of developing atherosclerosis and atherosclerotic lesions are essentially an inflammatory response. The aim of this study was to evaluate the effect of a medically supervised, multidisciplinary weight loss program on endothelial functions and circulating levels of proinflammatory cytokines in obese women. Twenty healthy pre-menopausal obese women and 20 age-matched normal weight women were studied. Endothelial functions were assessed by evaluating the response of blood pressure and platelet aggregation to an intravenous bolus of L-arginine (3 g), the natural precursor of nitric oxide. In obese women, the vascular and rheological responses to L-arginine were significantly lower (p < 0.05) at baseline, as compared with non-obese women, indicating endothelial dysfunction; on the contrary, basal concentrations of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) were significantly higher (p < 0.01). After one year of a multidisciplinary program of weight reduction consisting of diet, exercise and liposuction surgery, all obese women lost at least 10% of their original weight (10.5 +/- 1.7 kg, range 7.9-13.9 kg). Compared with baseline, sustained weight loss was associated with reduction of cytokine (p < 0.01) concentrations and with improvement of vascular responses to L-arginine. In conclusion, a multidisciplinary approach aimed at inducing a sustained reduction of body weight in obese women is feasible and is associated with improvement of endothelial functions and reduction of circulating proinflammatory cytokine concentrations.