Analytical performance of the Synchron LX®20 Pro, BN™II and IMMAGE® high sensitivity C-reactive protein assays and concordance in cardiovascular risk stratification

Optimization of the secretory expression of recombinant human C-reactive protein in Pichia pastoris

Human C-reactive protein (CRP), a classical human acute-phase plasma protein, is not only a sensitive systemic inflammatory marker but also an independent risk predictor of cardiovascular diseases. However, existing heterologous expression systems for expressing CRP is not efficient and cost-effective for large-scale industrial production of CRP to meet the growing market demand for CRP. This study aims to improve the secretion of recombinant CRP by Pichia pastoris via optimizing signal peptides, promoters and carbon sources. The CRP genes with encoding four different signal peptides were designed and synthesized. The genes were cloned into pPICZαA or pPICZ B, respectively via splicing by overlap extension polymerase chain reaction (SOE-PCR) technology and expressed in P. pastoris X-33, regulated by the alcohol oxidase I promoter (pAOX1). The CRP led by the α-mating factor secretion signal peptide (α-MF) was secreted at the highest level in these signal peptides. Then, a constitutive construct and expression of the CRP genes were achieved by switching to the glyceraldehyde-3-phosphate dehydrogenase promoter (pGAP). Subsequently, different carbon sources and at different concentrations were used to further improve the secretion of CRP. The expression of CRP with the α-MF driven by the pGAP gave the highest yield of secreted CRP, about 3 mg/l of culture on the optimized culture conditions. The purified recombinant CRP exhibited good immunoreactivity determined by ELISA with anti-human CRP monoclonal antibody. The efficient engineering strategy established in this work might provide potential uses in large-scale industrial production of human CRP in the future.

Differences and interactions between risk factors for coronary spasm and atherosclerosis--smoking, aging, inflammation, and blood pressure

Objective Coronary spasm as well as atherosclerosis plays an important role in the pathogenesis of coronary heart disease. However, the relationship between coronary spasm and atherosclerosis is not well known. The purpose of the present study was to examine the differences and interactions between risk factors for coronary spasm and atherosclerosis and thereby explore the pathogenesis of coronary spasm. Methods The study subjects consisted of 938 patients with chest discomfort (522 men and 416 women, mean age 65.2±11.0) who underwent intracoronary-acetylcholine provocation tests for coronary spasm. Coronary risk factors, including age, gender, body mass index, blood pressure, high-sensitivity C-reactive protein (hsCRP), white blood cells, glucose, lipid profiles, and other laboratory chemistries were examined. Results Four hundred and ninety-six patients (315 men and 181 women, mean age: 65.1±11.4) were diagnosed with coronary spastic angina (CSA), while the remaining 442 patients (207 men and 235 women, mean age: 65.3±10.7) were diagnosed with non-CSA. A multiple logistic regression analysis revealed men, smoking, hsCRP, and low diastolic blood pressure (DBP) to be predictors (p=0.001, p=0.009, p=0.034, and p=0.041, respectively) for CSA, while age, diabetes mellitus, low high-density lipoprotein-cholesterol, systolic blood pressure (SBP), uric acid and male gender were found to be predictors (p<0.001, p<0.001, p<0.001, p=0.002, p=0.006 and p=0.029, respectively) for atherosclerosis. Conclusion Predictors for coronary spasm were smoking, hsCRP and low DBP, whereas those for atherosclerosis were age, diabetes mellitus, high SBP, and uric acid in that order. These findings suggest that the pathogenesis of coronary spasm differs from that of atherosclerosis.

Few associations between high-sensitivity C-reactive protein and environmental factors in 4.5-year-old children

BACKGROUND

Low-grade inflammation in early childhood might protect from allergic diseases later in life. Our aim was to examine the effects of different environmental factors on low-grade inflammation measured with serum high-sensitivity C-reactive protein (hsCRP) at the age of 4.5 years.

METHODS

The high-sensitivity CRP values (n = 653) and serum-specific IgE concentrations were measured from 4.5-year-old children in rural areas in five European countries (Austria, Finland, France, Germany, and Switzerland). Children belonged to the prospective multi-center PASTURE birth cohort. Data on early and current farming environment and domestic animal exposure were collected by questionnaires.

RESULTS

Females as well as obese or very obese children at age of 4.5 years had higher hsCRP values than males (aOR 1.84 95% CI 1.27-2.66) and healthy weight children (aOR 4.47 95% CI 1.94-10.31), respectively. Levels were lowest in the summer. Few associations were detected between hsCRP values and farm environmental factors or atopic sensitization. However, there was evidence of children with low levels of hsCRP (below the detection limit) who had increased prevalence of sensitization to inhaled and seasonal allergens. Among non-sensitized children, spending time in stables was associated with reduced hsCRP (15 min-10 h aOR 0.40 95% CI 0.16-0.96 and ≥10 h aOR 0.25 95% CI 0.07-0.90), and among sensitized children, maternal smoking was associated with higher hsCRP values (aOR 2.51 95% CI 1.12-5.59).

CONCLUSION

We found few associations between early environmental farming factors and hsCRP levels, and between hsCRP levels and atopic sensitization in 4.5-year-old children. However, our results suggest that the role played by the environmental factors in low-grade inflammation may differ between sensitized and non-sensitized children.

Dose-dependency in pleiotropic effects of atorvastatin

Statins are recognized as the principal and most effective class of drugs for reducing serum cholesterol levels and, therefore, significantly reducing cardiovascular events and mortality. Statins may have a wide range of beneficial biological effects in addition to lipid lowering, a phenomenon commonly termed a 'pleiotropic effect'. However, the dose-dependency of these effects remains unclear. The present study evaluated whether atorvastatin, a potent statin, ameliorates the serum markers of pleiotropic effects, with a focus on dose-dependency. The pleiotropic effects of treatment with atorvastatin 5 mg/day and 10 mg/day for six months each in 15 patients with primary hypercholesterolemia were assessed in a prospective, randomized, open-label, crossover, single-centre study. Atorvastatin treatment dose-dependently decreased a serum marker of oxidative stress as well as the serum low-density lipoprotein cholesterol level. However, serum markers of inflammation and fibrinolysis decreased independently of dose. In conclusion, the dose-dependency of atorvastatin's pleiotropic effects differs among individual biological effects.

Change in waist circumference over 11 years and current waist circumference independently predict elevated CRP in Filipino women

C-reactive protein, a marker of chronic, low-grade inflammation, is strongly associated with current central adiposity, and has been linked to elevated risk of cardiovascular disease. Less is known about the contribution of longitudinal change in waist circumference to current inflammation. We evaluated the extent to which current waist circumference and change over an 11-year interval contribute independently to low-grade systemic inflammation measured in a group of 1,294 women, 35-69 years, participating in the Cebu Longitudinal Nutrition and Health Survey in the Philippines. Waist circumference was measured at the time of blood draw for CRP analysis in 2005 and during an earlier survey in 1994. A waist circumference delta variable was constructed by subtracting current circumference from past circumference. We used logistic regression models to predict having an elevated plasma CRP concentration (3 mg L(-1) < CRP < 10 mg L(-1)). Waist circumference in 2005 was a strong predictor of elevated CRP (OR 1.10, 95% CI = 1.08, 1.12, P < 0.001). In combined models, increase in circumference over 11 years was a significant and independent predictor of elevated CRP risk (OR = 1.023, 95% CI = 1.00, 1.05, P < 0.05). Considering the average increase over time, the cumulative risk of elevated CRP due to increased central adiposity was 25.7%. However, women who reduced their waist circumference between 1994 and 2005 had greatly reduced risk (6.2%), suggesting that even long-term inflammatory burden can be reversed by weight loss. Although current waist circumference is an important contributor to risk of elevated systemic inflammation in this as in other populations, history of central adiposity may be an independent phenomenon.

Population differences in associations between C-reactive protein concentration and adiposity: comparison of young adults in the Philippines and the United States

BACKGROUND

Inflammation may be an important mediator of the association between nutrition and cardiovascular diseases, but most studies have been conducted in Western populations with high rates of overweight and obesity and low levels of infectious disease.

OBJECTIVES

This study sought to investigate the predictors of C-reactive protein (CRP) in young adults living in the Philippines and to examine patterns of association with adiposity compared with young adults in the United States.

DESIGN

Maximum likelihood logistic regression models were used to predict elevated high-sensitivity CRP (>3 mg/L) in relation to anthropometric measures of adiposity, symptoms of infectious disease, and proxy measures of pathogen exposure in men and women from the Philippines (n = 1648; age: 20-22 y). Comparative data were drawn from a nationally representative sample in the United States (National Health and Nutrition Examination Survey; n = 616; age: 19-24 y).

RESULTS

Median concentrations of CRP were substantially lower in the Philippines (0.2 mg/L) than in the United States (0.9 mg/L), and the likelihood of elevated CRP was lower in the Philippines than in the United States at the same level of waist circumference or skinfold thickness. In the Philippines, infectious symptoms and pathogen exposure predicted elevated CRP, independent of adiposity.

CONCLUSIONS

Adiposity and infectious exposures are associated with elevated CRP in the Philippines; other populations undergoing comparable lifestyle and dietary changes associated with increasing rates of overweight and obesity are likely experiencing similar double burdens of inflammatory stimuli. Low concentrations of CRP in this Philippine sample raise the question of whether CRP cutoffs based on European or European-American reference populations are appropriate for predicting disease risk in populations undergoing the nutrition transition.

Effects of a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, fluvastatin, on coronary spasm after withdrawal of calcium-channel blockers

OBJECTIVES

The purpose of this study was to determine whether a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) suppresses coronary spasm.

BACKGROUND

Coronary spasm is associated with endothelial dysfunction. Statins have been shown to improve endothelial function.

METHODS

This was a prospective, randomized, open-label, end point study. Sixty-four patients who had no significant organic coronary stenosis and in whom coronary spasm was induced by intracoronary injection of acetylcholine (ACh) were randomly assigned to fluvastatin 30 mg/day plus the conventional calcium-channel blocker (CCB) therapy (31 patients, statin group) or the conventional CCB therapy (33 patients, nonstatin group). After 6 months of treatment, the intracoronary injection of ACh was repeated and the coronary spasm was assessed.

RESULTS

Coronary spasm was suppressed in 16 of the 31 patients (51.5%, p < 0.0001) of the statin group and in 7 of the 33 patients (21.2%, p = 0.0110) of the nonstatin group after 6 months of treatment. Thus, the number of patients with ACh-induced coronary spasm was significantly reduced in the statin group as compared with the nonstatin group (51.6% vs. 21.2%, p = 0.0231) after 6 months of treatment.

CONCLUSIONS

The addition of fluvastatin 30 mg/day to the conventional CCB therapy for 6 months significantly reduced the number of patients with ACh-induced coronary spasm as compared with the conventional CCB therapy. Thus, a statin (fluvastatin) may possibly be a novel therapeutic drug for coronary spasm.

Coronary Spasm is Associated With Chronic Low-Grade Inflammation

BACKGROUND

Coronary spasm plays an important role in the pathogenesis of ischemic heart disease and it may be associated with low-grade inflammation.

METHODS AND RESULTS

Intracoronary injection of acetylcholine was done in 199 patients (99 men, 100 women, mean age, 64.5+/-11.0 years) with chest pain and normal coronary angiograms. According to the results of the provocation test, the study subjects were divided into 2 groups: the spasm group of 112 patients and the non-spasm group of 87 patients. Clinical data including high-sensitivity C-reactive protein (hs-CRP) and other coronary risk factors were compared between the 2 groups. Serum levels of hs-CRP were significantly higher in the spasm group than in the non-spasm group (median: 1.2 mg/L vs 0.5 mg/L, p<0.005). Multivariate analysis showed that hs-CRP and smoking history were independently associated with coronary spasm with an odds ratio of 2.28 (p=0.027) and 2.25 (p=0.037), respectively, with a hs-CRP value of > or = 2 mg/L as cutoff point.

CONCLUSIONS

Minor elevations of the serum hs-CRP level are significantly associated with coronary spasm, suggesting that chronic low-grade inflammation may be involved in the pathogenesis of coronary spasm.

An overview of inflammatory markers in type 2 diabetes from the perspective of the clinical chemist

C-reactive protein (CRP), when measured by a highly sensitive method, is a measure of lowgrade, chronic inflammation and is an independent risk factor for type 2 diabetes (T2D) and cardiovascular disease (CVD). CRP also has the capacity to interact with other risk factors to increase the risk for T2D and CVD. Population distributions divided into tertiles provide the capacity to predict onset of T2D and associated CVD. Preanalytical as well as analytical sources of variation in high-sensitivity CRP (hsCRP) measurements need to be standardized in order for CRP results to be optimally useful. The Centers for Disease Control and Prevention and the American Heart Association have issued guidelines for clinical usefulness of hsCRP measurements. The Centers for Disease Control and Prevention has taken steps to standardize hsCRP assays by evaluating secondary reference materials to be used by manufacturers to calibrate their assays.

Low-Grade Inflammation, Thrombogenicity, and Atherogenic Lipid Profile in Cigarette Smokers

BACKGROUND

Cigarette smoking is one of the major risk factors for atherosclerotic coronary disease, but the precise mechanism(s) by which cigarette smoking promotes atherosclerosis remains unknown. As there is now increasing evidence that atherosclerosis is an inflammatory condition, the present study investigated whether inflammation exists in smokers.

METHODS AND RESULTS

The inflammatory markers and lipid profiles were compared among a current-smoker group (210 patients, mean age 61.8 +/- 11.0 years), past-smoker group (115 patients, 67.1 +/- 9.0 years) and never-smoked group (113 patients, 68.2 +/- 10.7 years), all of whom had no apparent signs of inflammation. The respective levels of blood leukocytes, platelets, C-reactive protein and fibrinogen were significantly higher in current-smokers than in the never-smoked group (6,600 +/- 1,723 /microl vs 5,638 +/- 1,313 /microl p<0.01; 22.7 +/- 6.8 x 10(4) /microl vs 18.7 +/- 7.4 x 10(4) /microl, p<0.01; 3.50+/-4.91 mg/L vs 1.92+/-3.02 mg/L, p<0.01; 334.2 +/- 90.9 mg/dl vs 314.7 +/- 80.2 mg/dl, p<0.05). The respective levels of plasma triglycerides, remnant-like particle cholesterol and apolipoprotein-B were significantly higher and that of high-density lipoprotein cholesterol significantly lower in the current-smokers than in the never-smoked group (152.4 +/- 96.2 mg/dl vs 120.5 +/- 58.1 mg/dl, p<0.01; 5.4+/-6.3 mg/dl vs 3.8 +/- 2.0 mg/dl, p<0.05; 101.6 +/- 23.7 mg/dl vs 95.0 +/- 21.2 mg/dl, p<0.05; 45.2 +/- 12.3 mg/dl vs 50.6 +/- 15.6 mg/dl, p<0.01). Past smokers had intermediate values between those of current-smokers and never-smoked.

CONCLUSIONS

Low-grade inflammation, atherogenic dyslipidemia, and hypercoagulability are present in smokers compared with those who have never smoked among subjects without apparent inflammation who underwent coronary angiography on suspicion of coronary artery disease.