C-reactive protein and cardiovascular risk: an update on what is going on in cardiology

Oxidative Stress in Hemodialysis Patients: Pathophysiological Mechanisms, Clinical Consequences and Basic Principles of Treatment

Cardiovascular diseases are the leading cause of death in patients who undergo regular hemodialysis. Oxidative stress is a non-traditional risk factor for the development of cardiovascular diseases in this population of patients. It is defined as tissue damage caused by balance disturbance between the formation of free radicals and the function of protective antioxidative systems. The superoxide anion and hydrogen peroxide are precursors in the formation of stronger oxidants, such as: hydroxyl radical, peroxynitrite and hypochloric acid. Superoxide dismutase is the first line of antioxidant protection while catalase, glutathione peroxidase, trace elements, vitamin C, vitamin E, N-acetylcysteine and coenzyme Q10 also have a significant antioxidative role. Hemo-dialysis is itself a trigger for the increased formation of oxygen free radicals. The two main pathophysiological mechanisms of the increased formation of free oxygen radicals during the hemo-dialysis session are: bionicompatibility of the dialysis membrane and the presence of endotoxins in the hemodialysis solution. The measurement of myeloperoxidase concentration in a patient’s serum during hemodialysis is an indicator of the severity of oxidative stress induced by the dialysis membrane (an indicator of the biocompatibility of the dialysis membrane). The main clinical consequences of oxidative stress include: atherosclerosis, erythropoietin resistance, malnutrition and amyloidosis associated with hemodialysis. The evaluation of oxidative stress in patients undergoing hemodialysis is performed by measuring the concentration of lipid peroxidation products (malonyldialdehyde, 4-hydroxynonenal, TBARS, F2-isoprostane, oxLDL), protein oxidation (AOPP), protein gelling (AGE), and oxidation of nucleic acids (8-OHdG). The antioxidant treatment strategy consists of replenishing vitamin C, vitamin E, selenium, N-acetylcysteine and coenzyme Q10. On-line hemodialysis, a biocompatible vitamin E-coated dialysis membrane, an ultra-pure solution for hemodialysis, prevent oxidative stress, reduce the rate of cardiovascular morbidity and mortality and improve life quality of patients treated with regular hemodialysis.

Post-effort chances in C-reactive protein level among soccer players at the end of the training season

Numerous literature data point out the differences in immunological parameters as a result of physical effort and the relation of those changes to the subject's fitness level. This study was aimed at the assessment of soccer players' condition and adaptation to physical effort based on the changes in C-reactive protein (CRP) blood level. C-reactive protein, total protein, and albumin plasma levels before and after 60-minute-long outdoor running were determined among 16 (8 men and 8 women) soccer players. Statistically significant increase in total blood protein level was observed in both studied groups. However, there were no statistically significant changes in albumin level in soccer players' blood. Determination of CRP showed that the exercise test caused changes in its level among both women and men; yet, statistically significant increase in CRP level was found only in women's blood. The different influence of effort on CRP plasma level may be explained by the involvement of various mechanisms in regulation of acute-phase responses in different conditions. It was found in our study that CRP level could be a valuable tool to assess the metabolic response to aerobic exercise.

[The relationship between C-reactive protein and subclinical carotid arteriosclerosis in military pilots]

BACKGROUND/AIM

Inflammation plays a key role in the physiopathology of arteriosclerosis. C-reactive protein (CRP) and common carotid artery intima-media thickness are independent predictors of cardiovascular events and diabetes mellitus in apparently healthy men, but relationship between them is not fully elucidated. The aim of the study was to assess the cross-sectional relationship between CRP and cardiovascular risk factors with common carotid artery intima-media thickness in military pilots as representatives of healthy men.

METHODS

We studied 161 military pilots (age 38 +/- 6 years) free of cardiovascular disease and diabetes mellitus. Traditional and metabolic risk factors were determined. Plasma CRP was measured by immunonephelometry. The common carotid artery intima-media thickness was measured by ultrasonography in the posterior wall of both common carotid arteries.

RESULTS

A total of 66.5% subjects had common carotid artery intima-media thickness > 0.9 mm (p < 0.01). The mean CRP plasma concentration was significantly higher in the subjects with common carotid artery intima-media thickness > 0.9 mm than in those with common carotid artery intima-media thickness < or = 0.9 mm. In a simple regression analysis age adjusted CRP was associated with common carotid artery intima-media thickness (beta = 0.285, p < 0.01), and only high density lipoprotein cholesterol was not associated with common carotid artery intima-media thickness. The association between CRP and common carotid artery intima-media thickness remained highly significant after controlling for body mass index, blood pressure, total cholesterol, low density lipoprotein cholesterol, triglycerides, glycosylated hemoglobin and smoking (p < 0.01). Controlling for glucose, triglycerides to high density lipoprotein cholesterol ratio, and total cholesterol to high density lipoprotein cholesterol ratio resulted in some reduction in the strength of the association, but including waist circumference in the regression made the relationship no longer significant (p = 0.119). Body mass index (beta = 0.352; p < 0.01), total cholesterol to high density lipoprotein cholesterol ratio (beta = 0.334; p < 0.01) and age (beta = 0.190; p = 0.036) were the independent predictors of common carotid artery intima-media thickness.

CONCLUSIONS

In the studied group of healthy men CRP per se is not an independent predictor of early arteriosclerosis, and may mediate the effect of certain traditional risk factors, especially visceral obesity, on promoting aterogenesis.

Variations in C-reactive protein, plasma free radicals and fibrinogen values in patients with osteoarthritis treated with Pycnogenol

In a previous, double-blind, placebo-controlled study we evaluated the efficacy of a 3-month treatment with Pycnogenol for 156 patients with osteoarthritis of the knee. Pycnogenol significantly decreased joint pain and improved joint function as evaluated using the WOMAC score and walking performance of patients on a treadmill. In this study, we further investigated the anti-inflammatory and antioxidant activity of Pycnogenol in a subset of the osteoarthritis patients presenting with elevated C-reactive protein (CRP) and plasma-free radicals. Elevated CRP levels have been suggested to be associated with disease progression in osteoarthritis. In our study, 29 subjects of the Pycnogenol group and 26 patients in the placebo group showed CRP levels higher than 3 mg/l at baseline. Comparison of blood specimens drawn at baseline and after 3-month treatment showed that Pycnogenol significantly decreased plasma free radicals to 70.1% of baseline values. Plasma CRP levels decreased from baseline 3.9 mg/l to 1.1 mg/l in the Pycnogenol group whereas the control group had initial values of 3.9 mg/l which decreased to 3.6 mg/l. The CRP decrease in the Pycnogenol was statistical significant as compared to the control group (P < 0.05). Fibrinogen levels were found to be lowered to 62.8% of initial values (P < 0.05) in response to Pycnogenol. No significant changes for plasma free radicals, CRP and fibrinogen were found in the placebo-treated group. The decrease of systemic inflammatory markers suggests that Pycnogenol may exert anti-inflammatory activity in osteoarthritic joints and patients did not present with other ailments or infections. The nature of the anti-inflammatory effects of Pycnogenol with regard to CRP warrants further investigation.

Biomarkers in drug discovery and development

Biomarkers have shown promising utilities at various stages of the pharmaceutical R & D. With the recent technological advancements and the introduction of protein and gene arrays, high performance instrumentation (e.g., high-field nuclear magnetic resonance and high-resolution mass spectrometers), and bioinformatics, decisions on safety and efficacy criteria can be made with a higher degree of confidence. However, there is a scarcity of robust and valid biomarkers to accelerate the drug development process from pre-clinical through all stages of clinical studies. In this article, a brief overview of current definitions, biomarker categories, challenges in biological and analytical validation, along with several clinical examples will be presented.

Cardiac troponin I and beta 2 microglobulin as risk factors for early-onset atherosclerosis in patients on haemodialysis

AIM

To investigate the associations of different risk factors with carotid artery intima-media thickness (C-IMT) in non-diabetic haemodialysis (HD) patients who had no clinical evidence of atherosclerosis.

METHODS

Seventy-two HD patients (43 men, 29 women; mean age: 34.5 +/- 10.6 years; mean time on HD: 47.9 +/- 40.0 months) and 40 age- and sex-matched healthy controls (26 men, 14 women; mean age: 35.5 +/- 7.1 years) participated in the study. The relationship between C-IMT and haematocrit-corrected erythrocyte sedimentation rate (Hct-corrected ESR), beta 2 microglobulin (beta2M) and serum cardiac troponin I (cTnI) levels beyond C-reactive protein (CRP), lipid profile and lipoprotein(a), fibrinogen, homocysteine and left ventricular hypertrophy (LVH) were examined.

RESULTS

Mean C-IMT of the HD patients was significantly greater than that of the control subjects (0.59 +/- 0.06 vs 0.53 +/- 0.07 mm, P = 0.002). C-IMT of patients was positively correlated with age (r = 0.33), body mass index (r = 0.40), Hct-corrected ESR (r = 0.37), CRP (r = 0.34), beta2M (r = 0.34), cTnI (r = 0.26), triglyceride (r = 0.26) and fibrinogen (r = 0.28) levels (P < 0.05 for all). The mean C-IMT was significantly greater in patients with LVH than it was in those without LVH (P = 0.004). In multivariate regression analysis, age (P = 0.02), beta2M (P = 0.001), log-transformed CRP (P = 0.03) and LVH (P = 0.01) were independently related with C-IMT.

CONCLUSION

Besides well-known cardiovascular (CV) risk factors, cTnI and beta2M were related with C-IMT in that they may have important roles in early-onset atherosclerosis in this high-risk population.

Is serum C-reactive protein concentration correlated with HbA1c and insulin resistance in Type 2 diabetic men with or without coronary heart disease?

BACKGROUND AND AIMS

C-reactive protein (CRP) is an inflammatory marker that predicts coronary heart disease (CHD) risk. Diabetes mellitus (DM) counts as a CHD risk equivalent. We aimed to compare serum high sensitivity CRP (hs-CRP) levels in Type 2 diabetic (T2DM) men without CHD, non-diabetic CHD patients and T2DM patients with CHD.

SUBJECTS AND METHODS

Four groups were formed; Group 1 [DM(+), CHD(-), no.=25], Group 2 [DM(-), CHD(+) no.=25], Group 3 [DM(+), CHD(+), no.=25], and Group 4 (controls, no.=30). Serum hs-CRP, insulin, glucose, total, HDL-, LDL- and VLDL-cholesterol, triglyceride levels and homeostasis model assessment for insulin resistance (HOMA-IR) index were determined.

RESULTS

Mean hs-CRP level of Group 1 (0.6+/-0.29) was not different statistically from Group 2 (1.44+/-0.97). Mean hs-CRP levels were higher in men with CHD, whether they were diabetic (Group 3; 3.83+/-2.01 mg/dl) or non-diabetic (Group 4), than in control subjects (0.16+/-0.15; p=0.0001 and p<0.004, respectively). Mean hs-CRP level of Group 3 was also higher than Group 2 (p=0.0001). There was a positive correlation between serum hs-CRP and glycated hemoglobin (HbA1c; r=0.277, p<0.01), fasting insulin (r=0.336, p<0.02) and HOMA-IR (r=0.348, p<0.02) in T2DM men with or without CHD.

CONCLUSIONS

T2DM men without CHD had similar CRP levels with non-diabetic CHD patients, whereas CRP levels of T2DM men with CHD were higher than non-diabetic men with CHD. Because of a positive correlation between serum hs-CRP and HbA1c, fasting insulin and HOMA-IR, inflammation, insulin resistance and hyperglycemia jointly contribute to the cardiovascular risk in T2DM men.

C-reactive protein is associated with psychological risk factors of cardiovascular disease in apparently healthy adults

OBJECTIVE

The current study examined the relation of anger, hostility, and severity of depressive symptoms, alone and in combination, to C-reactive protein (CRP) in healthy men and women.

METHODS

A high sensitivity enzyme linked immuno sorbent assay (ELISA) was used to evaluate CRP levels in a multiethnic sample of 127 healthy, nonsmoking men and women. Fasting blood samples were collected the same day the assessments were done of anger and hostility using the Buss-Perry Aggression Questionnaire (BPAQ) and depressive symptomatology using the Beck Depression Inventory (BDI). A psychological risk factor (PRF) score representing a composite summary indicator of BDI and BPAQ-anger and -hostility was generated using principal component analysis. Log-transformed CRP values were examined using univariate and multivariate analyses adjusting for control variables of age, gender, body mass index (BMI), alcohol use, exercise frequency, ratio of total to high-density lipoprotein cholesterol, and family history of premature coronary heart disease (CHD).

RESULTS

Log-normalized CRP was correlated with BDI (r = 0.21, p =.02) and BPAQ anger (r = 0.20, p =.02), but not with BPAQ hostility. After adjustment for control variables, BDI (beta = 0.05, p =.011), BPAQ anger (beta = 0.05, p =.007), and the PRF composite score (beta = 0.27, p =.005), but not BPAQ hostility (beta = 0.03, p =.11), were significantly associated with log-normalized CRP.

CONCLUSIONS

Greater anger and severity of depressive symptoms, separately and in combination with hostility, were significantly associated with elevations in CRP in apparently healthy men and women. These associations were independent of potential confounding factors.