Nontraditional cardiovascular risk factors

Nutritional Genomics of Cardiovascular Disease

PURPOSE

Cardiovascular disease (CVD) is the leading cause of death in the United States and globally. There is significant evidence implicating genetic and dietary factors in the development and progression of CVD and its risk factors. Nutritional genomics is a comparatively new field of science that focuses on the relationship of individual genetic variation with response to nutrition. The purpose of this review is to summarize recent progress, in the field of nutritional genomics as it relates to cardiovascular disease.

RECENT FINDINGS

Evidence from recent studies has shown significant effects of gene-diet interactions on CVD biomarkers and the development and progression of CVD. The cardiovascular effects of gene-nutrient interactions with respect to macronutrients and genes such as FTO, ACE, PPARs, TCF7L2, BDNF, MC4R, APOAs, FADS, etc. have shown consistent results across age groups and populations whereas gene-nutrient interaction effects of other genes have only been limited to specific ages, genders or populations and need to validated and confirmed.

SUMMARY

The identification of individual genetic variation influencing diet-related CVD risk is important and may inform future nutritional intervention studies. Although there is ample scientific evidence indicating that the genetic susceptibility to CVD can be modified by diet, we are still not at a stage where this information is easily translated into dietary plans. Thus, there is a need for better approaches to achieve precision in dietary data collection and streamline computational approaches for meaningful and effective nutritional interventions.

Cardiovascular risk factors as causes for hearing impairment

The purpose of this paper is to provide a contemporary review of the correlation between cardiovascular risk factors (CVRFs) and hearing impairment (HI) . We conducted a comprehensive review of the literature in order to assess the effects of the different CVRFs on HI. We focused on the pathological findings in the inner ear and their correlation with cochlear function in population-based studies. We found that CVRFs adversely affect hearing acuity. HI diagnosis should be accompanied by detecting and treating CVRFs, according to the presented outline, which may augment hearing rehabilitation and improve the general health and the well-being of the patient. © 2014 S. Karger AG, Basel.

Development of an immunopredictor for the evaluation of the risk of cardiovascular diseases based on the level of soluble P-selectin

Due to its physiologic role in modulating adhesive interactions between blood cells and the endothelium during inflammatory processes or at injury sites, the adhesion molecule P-selectin is of great interest. The level of soluble P-selectin in plasma or serum can be detected and used as a clinical predictor for adverse cardiovascular events, leading to the presumption that it is secreted, shed or cleaved from the cell membrane during the process of diseases. Increased levels of soluble P-selectin in the plasma have been shown to be associated with a range of cardiovascular disorders, including coronary artery disease, hypertension and atrial fibrillation. Therefore, it is of huge significance to develop simple, rapid and sensitive methods for the detection of such pathological predictors, not only for facilitating the surveillance of cardiovascular mortality/sudden cardiac death, but also for effectively monitoring the drug potency on platelets based on measurement of P-selectin performed on fixed blood samples following platelet stimulation in whole blood in a remote setting. We herein developed a simple, yet novel and sensitive electrochemical sandwich immunosensor for the detection of P-selectin; it operates through covalent linkage of anti-P-selectin antibody on CNT@GNB nanocomposites-modified disposable screen-printed electrode as the detection platform, with the potassium ferrocyanide-encapsulated, anti-P-selectin-tagged liposomal biolabels as the electrochemical signal probes. The immunorecognition of the sample P-selectin by the liposomal biolabels occurred on the surface of the electrodes; the release of potassium ferrocyanide from the bound liposomal biolabels extensively contributed to the increase in electrochemical signal, which was acquired in HCl solution at +0.32V in square wave voltammetry mode. The resulting sigmoidally shaped dose-response curves possessed a linear dynamic working range from 1×10(-13) to 1×10(-5)g/mL. This liposome-based electrochemical immunoassay provides an amplification approach for detecting P-selectin at trace levels, leading to a detection limit as low as 4.3fg (equivalent to 5μL of 0.85pg/mL solution). A commercially available ELISA kit was used as a reference method to validate the newly-developed assay through the analysis of mouse serum samples. A strong correlation was observed between the two data sets as the R-squared value of 0.997 from the linear regression line. This electrochemical immunosensor will be useful for the detection of P-selectin in biological fluids and tissue extracts.

Effects of a skullcap root supplement on haematology, serum parameters and antioxidant enzymes in rabbits on a high-cholesterol diet

We studied the effects of Scutellaria baicalensis root on blood parameters and antioxidant enzyme activities in rabbits fed a high-cholesterol diet. Thirty-two New Zealand White rabbits were divided into four groups of eight animals each. They were fed a standard diet (C group), a diet with a 1% pure cholesterol supplement (CH group), a diet with a 1% pure cholesterol supplement and a 9% skullcap root supplement (CH+SR group), or a diet with a 9% skullcap root supplement (SR group). After 6 weeks, the rabbits fed the high-cholesterol diet had significantly decreased RBC and Hb levels and significantly increased MCV, MCH and Fe levels (p≤ 0.05). The skullcap root supplement had no adverse effects on the haematological parameters. The values for RBC, Hb, HCT, MCV, MCH and MCHC were similar in the skullcap root-treated and control rabbits. We also observed a remarkable elevation in the serum TC, LDL and TG levels at the end of the 6-week period. The rabbits fed the cholesterol diet showed decreased activity of the erythrocyte GSH-Px compared with the rabbits fed the basal diet. The GSH-Px activity was significantly higher in the rabbits fed the CH+SR diet than in those on the CH diet. The erythrocyte SOD activity was also significantly decreased in the rabbits on the CH diet. However, the CH+SR group rabbits showed significantly enhanced erythrocyte SOD activity. The SOD level in the CH+SR rabbits was 34.91 U/ml, which was a 23% increase (p≤ 0.05) in relation to the results for the CH group and only 15% diminished in relation to the control group. These results suggest that the dietary supplementation of skullcap root may improve rabbit antioxidant systems and protect against the risks from a high-cholesterol diet.

Valor predictivo de la lipoproteína (a) y la apolipoproteína A1 en pacientes con obstrucción coronaria valorada angiográficamente

BACKGROUND AND OBJECTIVE

To examine the relationship between blood levels of lipids, hemostatic and inflammatory markers and the presence of angiographycally evaluated coronary stenosis.

PATIENTS AND METHOD

We included 397 consecutive patients (267 males and 130 females) who were admitted to the hospital because of an acute episode of chest pain. Each patient underwent a coronariography using the Seldinger technique. A blood sample was drawn to analyze lipids -total cholesterol, high density lipoproteins-cholesterol (HDLc), triglycerides, low density lipoproteins-cholesterol (LDLc), apolipoprotein A1, apolipoprotein B100, lipoprotein (a)-, hemostatic (fibrinogen, D-dimmer), and inflammatory (C-reactive protein, leukocyte count) markers. To evaluate the differences between mean values of quantitative variables, the Student's t-test was used for parametric variables and the Mann Whitney U test for non-parametric variables. Categorical variables were compared using the chi-square test. A logistic regression analysis was employed to determine the influence of high levels of the studied parameters on the presence of coronary obstruction.

RESULTS

295 patients had coronary stenosis (group 1) and 102 had not a significant obstruction (group 2). Patients with coronary stenosis had higher values of lipoprotein (a), D-dimmer, C-reactive protein and leukocyte count and lower HDLc, apolipoprotein A1 and total cholesterol. When markers were dichotomized in high values (fourth quartile) and low (first-third quartile), high lipoprotein (a) (odds ratio [OR] = 2.508; 95% confidence interval [CI], 1.222-5.145) and apolipoprotein A1 levels (OR = 0.472; 95% CI, 0.267-0.837) were significant using the multivariate logistic regression model adjusted sex, tobacco and age.

CONCLUSIONS

Among patients undergoing coronary angiography, high lipoprotein (a) levels are independently associated with the presence of coronary obstruction whereas high apolipoprotein A1 values show a protective effect.

Psychosocial stress increases inflammatory markers and alters cytokine production across pregnancy

Previous work has shown that psychosocial stress is related to increases in serum levels of pro-inflammatory cytokines late in pregnancy, and a growing body of research suggests that increased inflammatory activity during pregnancy, generally, may have a negative impact on outcome. The present study further addressed these issues by assessing relationships between psychosocial stress, social support and serum cytokines in early, mid, and late pregnancy, and the effects of stress and social support on the production of cytokines by stimulated lymphocytes in late pregnancy. In addition, we examined relationships between stress, support, and serum C-reactive protein (CRP) during pregnancy. Elevated stress was not only related to higher serum IL-6 late in pregnancy as in our prior work, but this relationship was also evident during early pregnancy and elevated stress was also associated with lower IL-10 in early pregnancy. No relationships between stress and cytokines were apparent during the 2nd trimester of pregnancy. Elevated stress during the 2nd trimesters and low social support during the 3rd trimester were related to increased serum levels of CRP, further suggesting that psychosocial factors can contribute increased inflammation during pregnancy. Importantly, elevated stress levels across pregnancy were predictive of elevated production of the pro-inflammatory cytokines IL-1B and IL-6 by stimulated lymphocytes in the 3rd trimester, suggesting that stress during pregnancy affects the function of immune system cells. These findings further support the notion that prenatal stress alters maternal physiology and immune function in a manner consistent with increased risk of pregnancy complications such as preeclampsia and premature labor.

Role of vitamin E-coated membrane in reducing advanced glycation end products in hemodialysis patients: a pilot study

INTRODUCTION

Advanced glycation end products (AGEs) are markers of oxidative stress.

AIMS

To assess if a vitamin-E-coated dialyzer affects plasma AGE levels and endothelial function in hemodialysis patients.

METHODS

16 patients were dialyzed with a synthetic modified cellulose membrane (SMC, n = 8) or a vitamin E-coated dialyzer (n = 8), respectively. At week 32 endothelial function was determined as brachial artery flow-mediated dilatation (FMD). Total AGEs, free pentosidine (FP), protein-bound pentosidine (BP) and autoantibodies against oxidized LDL (ox-LDL-autoantibodies) were assessed at baseline (T0) and at 16, 32, 40 and 42 weeks (T16, T32, T40 and T42).

RESULTS

At T16 and T32 FP and BP were lower in vitamin E than in SMC (T 16: 88.7 +/- 8.96 vs. 124.2 +/- 11.90 pmol/ml plasma; p = 0.04, and 22.9 +/- 2.99 vs. 32.8 +/- 2.98 pmol/mg proteins; p = 0.04. T32: 78.7 +/- 8.54 vs. 123.7 +/- 10.15 pmol/ml plasma; p = 0.007, and 19.9 +/- 2.0 vs. 33.67 +/- 2.41 pmol/mg proteins; p = 0.001). In vitamin E, AGEs were lower at T32, T40 and T42 (946.7 +/- 80.91 vs. 1,351.2 +/- 179.33 AU/ml, p = 0.05; 986.9 +/- 59.63 vs. 1,509.9 +/- 154.17 AU/ml, p = 0.013; 890.3 +/- 73.70 vs. 1,453.9 +/- 153.16 AU/ml, p = 0.009). At T32 AGEs, ox-LDL autoantibodies and FMD were inversely correlated (R = -0.70 p = 0.007 and R = -0.59, p = 0.04, respectively).

CONCLUSIONS

Vit E-coated membrane reduces plasma AGEs levels and AGEs values are negatively correlated with FMD.

The effects of lipid-lowering drug therapy on cardiovascular responsiveness in type 2 diabetic patients

Type 2 diabetes is associated with a high prevalence of dyslipidaemia and a high incidence of cardiovascular disease. Lipid lowering therapy with HMG Co-A reductase inhibitors (statins) reduce the risk of cardiovascular events in type 2 diabetic and non-diabetic patients, effects which are believed to be partly due to improvements in vascular function. The aetiology of abnormal vascular function in type 2 diabetics is likely to be multifactorial and the pattern of vascular dysfunction in type 2 diabetes may differ from that which occurs in non-diabetic patients with dyslipidaemia. Abnormalities in endothelium derived hyperpolarising factor (EDHF) mediated vasodilation in resistance vessels may be more prominent in both type 1 and type 2 diabetes than in non-diabetic patients with endothelial dysfunction. The effects of lipid lowering therapy on vascular responsiveness may differ in type 2 diabetic patients from those found in non-diabetic patients. Statin therapy does not appear to improve responses to endothelial dependent vasodilators in type 2 diabetics, but may alter the ratio between nitric oxide (NO) and EDHF mediated responses. Fibrate therapy improves flow mediated dilation of brachial arteries in type 2 diabetic patients, but only appears to improve endothelium dependant vasodilator responses in resistance vessels when given in conjunction with co-enzyme Q.

[Vascular risk factors and renal failure]

Patients with chronic kidney disease (CKD) have a substantially increased risk of cardiovascular disease (CVD) compared with the general population. The high prevalence of established traditional risk factors for atherosclerosis (diabetes, hypertension, dyslipidemia) in these patients undoubtedly contributes to the accelerated rate of vascular disease. In addition, several hypotheses have emerged to explain the high prevalence of CVD in patients with chronic renal failure. Growing evidence has been gathered over the last 15 years regarding the role of uremia-related risk factors such as inflammation and oxidant stress in the pathogenesis of atherosclerosis in subjects with renal failure. This paper will review current knowledge regarding the potential role of these non-traditional or uremia-related risk factors for atherosclerosis with special emphasis on prevalence, cardiac risk, and management in patients with CKD.

Correlation between lipoprotein(a) and other risk factors for cardiovascular disease and diabetes in Cherokee Indians: the Cherokee Diabetes Study

PURPOSE

To study the age and gender effects on the distribution of lipoprotein (a) [Lp(a)] and its relationship with other cardiovascular disease (CVD) and diabetes risk factors in the participants of the Cherokee Diabetes Study (CDS) (1995-2000).

METHODS

The CDS is a population based cross-sectional study of diabetes and its risk factors in Cherokee Indians aged 5 to 40 years of Oklahoma. Lp(a) levels were measured in 2205 participants.

RESULTS

The median Lp(a) (mg/dL) levels in the females were not significantly different among four age groups (5-9, 10-19, 20-29, and 30-40 years). However, the 20- to 29-year-old males had significantly lower Lp(a) levels than the males 10 to 19 and 30 to 40 years old. Females had significantly higher Lp(a) levels than males in the 20- to 29-year-old age group only. In the 5- to 19-year-old children/adolescents, Lp(a) levels were significantly negatively correlated with the degree of Indian heritage (DIH) and positively correlated with total cholesterol (TC), low-density lipoproteins (LDL), and apolipoprotein B (apoB) in girls, but not in boys. In the young adults aged 20 to 29 years, Lp(a) levels were significantly correlated with DIH, body mass index (BMI), waist-hip ratio (WHR), percentage of body fat (PBF), systolic blood pressure (SBP), triglycerides (TG), 2-hour plasma glucose (2hPG), and insulin in males, and DIH, PBF, TC, LDL, TG, and insulin in females. In adults aged 30 to 40 years, Lp(a) levels were significantly correlated with DIH, TG, and LDL in females, and DIH and insulin in males.

CONCLUSION

In the girls, Lp(a) levels appear to be associated with several CVD and diabetes risk factors at an early age (5-19 years), while in the boys, the association occurs at older ages (> 19 years). There are significant age and gender differences regarding the distribution of Lp(a) and its correlates in the 5 to 9, 10 to 19, and 20 to 29-year-old age groups, but the differences tend to be weaker in the 30- to 40-year-old age group. For the same age and gender groups, Lp(a) concentrations in Cherokee Indians were much lower than those reported in blacks and slightly lower than those in whites. In Cherokee Indians, the Lp(a) levels were consistently and positively correlated with LDL, and negatively correlated with DIH, TG, and insulin.

Prescribe by Risk: The Utility of a Biomarker-Based Risk Calculation in Disease Management to Prevent Heart Disease

Preventive treatment for those most at risk of heart disease rather than those with the highest blood pressure or cholesterol values may be a more efficacious strategy for disease management. This depends on accurate biomarker-based risk assessment tools. An evidence-based model of heart disease risk was developed using the Framingham model with an additional five risk factors, including three of the newer blood biomarkers. This was applied to the adult population of the 3rd National Health and Nutrition Examination Survey cohort. Additionally, the selection criteria for therapeutic intervention from the Adult Treatment Panel III guidelines (for hyperlipidemia) and the 7th Report of the Joint National Committee (for hypertension) were applied to the same subjects. Of this cohort 54% qualified for at least one of these medications while 18% qualified for both. Using this 18% cutoff, the 18% of the subjects with the highest calculated heart disease risk were also identified using the developed risk model. We applied established therapeutic reductions in heart disease probability to those identified by guidelines and to those identified by risk. Applying both drugs to the high-risk group (one third the size of the guidelines group) achieved the same reduction in population risk (about one fourth) as applying the drugs to the guideline groups and required only half as many prescriptions. Intermediate results were found when an intervention group was identified by a combination of both high risk and high levels of risk factors. In this simulation, identifying patients by heart disease risk level resulted in substantially fewer people being treated with fewer drugs and achieving a similar reduction in disease risk.

Herpes viruses, cytokines, and altered hemostasis in vital exhaustion

OBJECTIVE

Infections with herpes viruses have been implicated in the pathogenesis of atherosclerosis. We tested the hypothesis that vital exhaustion (VE) is associated with multiple herpesvirus infections, such as herpes simplex virus, varicella-zoster virus, Epstein-Barr virus, and cytomegalovirus, and with an increase in pathogen burden (ie, the aggregated seropositivity to immunoglobulin G antibodies for herpes simplex virus, varicella-zoster virus, Epstein-Barr virus, and cytomegalovirus). In addition, we examined the association of VE and pathogen burden with measures of hemostasis and inflammation.

METHODS

Blood samples were drawn from 29 men with VE and 30 male control subjects, all healthy and nonsmokers, to assess serological evidence of infection and measures of hemostasis and inflammation.

RESULTS

VE is associated with a relatively high pathogen burden, altered hemostasis, and higher levels of cytokines, such as interleukin-6. Across all subjects, a relatively high pathogen burden was also associated with altered hemostasis but not with increased cytokine levels. The interaction of VE with pathogen burden revealed significant linear increases in measures of hemostasis and inflammation. Finally, immunoglobulin G antibody titer levels of individual herpesvirus infections were not associated with hemostatic measures or with cytokines.

CONCLUSIONS

We conclude that stress-related alterations in hemostasis and inflammation are not necessarily linked to one particular herpesvirus infection but rather to an increase in aggregated seropositivity to herpesvirus infections.

Plasma thiols and androgen levels in polycystic ovary syndrome

Homocysteine is a risk factor for ischemic heart disease; similarly as is hyperlipidemia or insulin resistance, which frequently occur in women with polycystic ovary syndrome. We examined the relationships between thiols and hormonal status or insulin resistance in 40 women (aged 25.8 +/- 7 years) with polycystic ovary syndrome and in 11 controls (33 +/- 5 years). Blood levels of homocysteine, glutathione, total and high density lipoprotein (HDL)-cholesterol, triglycerides, insulin, sex hormone-binding globulin, testosterone, androstenedione, dehydroepiandrosterone sulfate, and estradiol were determined. Student's t test and Spearman correlations were computed after adjustment for body mass index (BMI) and age. Homocysteine was significantly higher in polycystic ovary syndrome patients than in the control group (10.3 +/- 2.87 vs. 8.78 +/- 2.75 micromol/l; p < 0.05). In women with polycystic ovary syndrome, there were significant positive correlations between homocysteine and androstenedione (r = 0.329; p < 0.05) and glutathione and dehydroepiandrosterone sulfate (DHEA-S) (r = 0.469; p < 0.05). We conclude that homocysteine is increased in women with polycystic ovary syndrome and is probably linked to androgen levels but not to markers of insulin resistance or with lipid metabolism.

C-reactive protein as a predictor of improvement and readmission in heart failure

OBJECTIVES

Only recently, new risk factors to explain atherosclerotic disease have been identified. One of the most important clinical manifestations of atherosclerosis is heart failure. Our study was aimed at investigating C-reactive protein (CRP), a marker of systemic inflammation, in the context of heart failure, and to determine its usefulness in predicting the need for readmission in patients with heart failure and their degree of improvement.

DESIGN

We studied patients admitted to our hospital due to heart failure, independent of the cause. CRP levels were measured with a sensitive standard assay on a Nephelometer analyser. Patients were classified on admission and discharge following New York Heart Association (NYHA) functional criteria; left ejection fraction was also determined by transthoracic echocardiography. Patients presenting clear sources of infection or inflammatory disease were excluded. Our control group consisted of patients admitted for syncope. Each patient was followed up through a computer system controlling admissions to and discharge from the hospital, for a period of 18 months after initial admission. End points considered were NYHA functional class on discharge, readmission and death.

RESULTS

We studied prospectively 76 patients with a mean age of 73.5+/-11 [95% confidence interval (CI) 71.2-75.8]; 44 were male (58%) and 32 female (42%). The mean CRP level in patients with heart failure was 3.94+/-5.87 (95% CI, 1.26-7.60), while in 15 patients with syncope it was 0.84+/-1.95 (95% CI, 0.96-2.94) (P=0.0007). The principal causes of heart failure included dilated cardiomyopathy due to coronary arterial disease (30%), valvular disease (28%) and heart failure secondary to hypertension (25%). The mean left ejection fraction adequately measured in 72 (95%) patients was 50.41+/-9.88 (95% CI, 41.20-59.65). We observed a trend of higher CRP levels in relation to ejection fractions below 35%: 7.50+/-9.88 vs. 3.75+/-4.57, (P=0.09). Our results showed that on discharge CRP levels increased in relation to NYHA class: I: 0.74+/-0.69; II: 3.78+/-3.76; III: 7.4+/-8.65; IV: 12.2+/-15.27 (P<0.05). On follow-up of each patient for 18 months, 32 (43%) were readmitted due to deterioration of their heart condition. For patients who were readmitted, those presenting CRP levels >0.9 mg/dl were identified as candidates for earlier hospitalisation than those with levels below 0.9 mg/dl (P=0.02) RR=1.43. In logistic-regression analysis the only group of tested variables predicting readmission were levels of CRP, NYHA class and plasmatic K on discharge and left ventricle ejection fraction. Analysis of covariates yields CRP levels as being an independent predictor of readmission.

CONCLUSIONS

An inflammatory response is present in deteriorating heart failure. We observed higher CRP levels in patients with higher NYHA functional class, perhaps signalling a poor therapeutic response. Higher CRP levels were also related to higher rates of readmission and mortality and it could be an independent marker of improvement and readmission in heart failure.

Accelerated atherosclerosis, dyslipidemia, and oxidative stress in end-stage renal disease

Premature atherosclerosis is a major cause of morbidity and mortality in end-stage renal disease patients. Dyslipidemia and increased oxidative stress contribute to premature atherogenesis in these patients. The dyslipidemia of end-stage renal disease consists of both quantitative and qualitative abnormalities in serum lipoproteins. Qualitative changes include hypertriglyceridemia (increased remnant lipoproteins), low high-density lipoprotein-cholesterol, and increased lipoprotein (a). In addition to quantitative changes, lipoproteins in end-stage renal disease undergo compositional and qualitative changes that make them pro-atherogenic, such as various modifications of apolipoprotein B, including oxidation, and modification by advanced glycation end-products. The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors and low-dose fibrates could be effective therapies for lipid disorders. The best evidence for increased oxidative stress in end-stage renal disease is the demonstration of increased plasma F2-isoprostanes. Confirmation of the positive findings with high-dose alpha-tocopherol in the Secondary Prevention with Antioxidants of Cardiovascular Disease in End-stage Renal Disease Study is urgently needed. Clinical trials with statins and other drugs that improve dyslipidemia also need to be undertaken. These therapies could clearly lead to a reduction in cardiovascular morbidity and mortality in these patients.

Lipoprotein(a) in American Indians is low and not independently associated with cardiovascular disease. The Strong Heart Study

PURPOSE

To evaluate the distribution of lipoprotein(a) (Lp(a)) and assess its association to cardiovascular disease (CVD) in American Indians.

METHODS

Lp(a) was measured in 3991 American Indians (aged 45-74 years with no prior history of CVD at baseline) from 13 communities in Arizona, Oklahoma, and South/North Dakota. They were followed prospectively from 1989 to 1997 for CVD. The distribution of Lp(a) was examined by center, sex, and diabetic status. Spearman correlation coefficients and Cox regression models were used to evaluate the association of Lp(a) to CVD.

RESULTS

A total of 388 participants subsequently developed CVD. Median Lp(a) concentration in American Indians was 3.0 mg/dl. This was almost half of that in whites and one sixth in blacks from the CARDIA study measured by the same method. Nondiabetic participants had significantly higher Lp(a) levels than diabetic participants for both genders. Lp(a) levels were higher in women than in men for nondiabetic participants, but there was no gender difference for diabetic participants. Correlation analysis showed Lp(a) was significantly negatively correlated with the degree of Indian heritage, insulin, triglycerides (TG), fasting plasma glucose (FPG), and 2-hour plasma glucose (2hPG), and positively with low-density lipoproteins (LDL), apoprotein B (apoB), and fibrinogen (FIB). In Cox regression models, adjusting for other risk factors, Lp(a) was no longer a significant predictor of CVD in either diabetic or nondiabetic participants.

CONCLUSIONS

The lower concentration of Lp(a) in American Indians and the high correlation with Indian heritage confirm the concept that Lp(a) concentration is in large part genetically determined. Lp(a) concentration is not an independent predictor of CVD among American Indians; it is higher in those who develop CVD because of its positive correlation with LDL, apoB, and FIB.

Screening for cardiovascular disease with cholesterol

BACKGROUND

Total cholesterol (TC) and lipoprotein measurements are among the major risk factors for cardiovascular disease (CVD).

ISSUES

The massive (and increasing) disease burden associated with cardiovascular disorders justifies public health measures, such as screening, which may assist with the identification and treatment of individuals who have a high risk of developing these disorders. Whole populations are placed at risk by environmental factors such as dietary habits and exercise patterns, and this may be reflected by simple tests such as TC that largely depend on dietary consumption of saturated fat and cholesterol. On the other hand, identification of high-risk individuals within populations requires more specific tests such as measurement of cholesterol in lipoprotein fractions. This recognizes that the contribution of different risk factors may vary between individuals. Dietary and pharmacological interventions, particularly those that reduce low-density lipoprotein cholesterol (LDL-C), have been shown to prevent the onset or recurrence of CVD.

CONCLUSIONS

It is desirable and justifiable to try to identify high-risk patients before the onset of clinical CVD because morbidity and mortality may occur as a consequence of the initial event. The relationship between the costs and the benefits of prophylactic interventions varies according to the extent to which clinical procedures, including laboratory testing, can estimate the level of cardiovascular risk. It can be argued that inappropriate cholesterol screening may have a negative effect on health economics and patient attitudes, but these problems appear easily surmountable. Techniques that enable the preclinical detection of CVD may help the process to strike a balance between public health initiatives that reduce the environmental factors responsible for the epidemic of CVD, and the strategies that are known to reduce event rates in high-risk individuals.

Risk factors for coronary disease: the time for a paradigm shift?

Risk stratification is a key element of clinical management not only in the primary and secondary prevention, but also during the acute stages of cardiovascular disease. The current risk assessment algorithms in primary prevention are based on established risk factors: gender and age, cigarette smoking, the presence of hypertension and diabetes mellitus, and serum concentrations of total cholesterol, low-density lipoprotein (LDL)-cholesterol and high-density lipoprotein-cholesterol. However, many individuals who are assessed as "low risk" on the basis of traditional risk factors, still develop cardiac events. This article addresses current issues relevant to the assessment of cardiovascular risk. It emphasizes the potential importance of disturbed energy supply for atherogenesis, by introducing the concept of fuel transport (chylomicron, VLDL, and remnants) and overflow (LDL) pathways of lipid metabolism. It highlights the present lack of routine methods to monitor the fuel transport pathway. It considers the measurements of serum C-reactive protein and plasma fibrinogen as new additions to the cardiovascular risk factor profiles. Finally, risk stratification based on the traditional and the new risk factors is linked to that based on the markers of acute myocardial damage such as cardiac troponin I or troponin T. It is concluded that the combined use of the markers of myocardial damage and the "new" cardiovascular risk factors is the way ahead for the assessment of cardiovascular risk.

Retinal microvascular abnormalities and their relationship with hypertension, cardiovascular disease, and mortality

Retinal microvascular abnormalities, such as generalized and focal arteriolar narrowing, arteriovenous nicking and retinopathy, reflect cumulative vascular damage from hypertension, aging, and other processes. Epidemiological studies indicate that these abnormalities can be observed in 2-15% of the nondiabetic general population and are strongly and consistently associated with elevated blood pressure. Generalized arteriolar narrowing and arteriovenous nicking also appear to be irreversible long-term markers of hypertension, related not only to current but past blood pressure levels as well. There are data supporting an association between retinal microvascular abnormalities and stroke, but there is no convincing evidence of an independent or direct association with atherosclerosis, ischemic heart disease, or cardiovascular mortality. New computer-related imaging methods are currently being developed to detect the presence and severity of retinal arteriolar narrowing and other microvascular characteristics. When reliably quantified, retinal microvascular abnormalities may be useful as risk indicators for cerebrovascular diseases.