Lipoprotein (a) and stroke

Serum lipoprotein(a) and reclassification of coronary heart disease risk; application of prediction in a cross-sectional analysis of an ongoing Iranian cohort

INTRODUCTION

Recent studies have introduced elevated lipoprotein(a) (Lp(a)) as a risk factor for coronary heart disease (CHD). This study investigated whether the addition of Lp(a) as a novel biomarker to the Framingham Risk Score (FRS) model improves CHD risk prediction.

METHODS

The study included 1101 Iranian subjects (443 non-diabetic and 658 diabetic patients) who were followed for 10 years (2003-2013). Lp(a) levels and CHD events were recorded for each participant.

RESULTS

The Net Reclassification Index (NRI) after adding Lp(a) to the FRS model was 19.57% and the discrimination slope was improved (0.160 vs. 0.173). The Akaike Information Criterion (AIC), a measure of model complexity, decreased significantly after adding Lp(a) to the FRS model (691.9 vs. 685.4, P value: 0.007).

CONCLUSIONS

The study concluded that adding Lp(a) to the FRS model improves CHD risk prediction in an Iranian population without making the model too complex. This could help clinicians to better identify individuals who are at risk of developing CHD and to implement appropriate preventive measures.

Significantly higher atherosclerosis risks in patients with obstructive sleep apnea and non-alcoholic fatty liver disease

Introduction

There is limited data on the relationship between Obstructive Sleep Apnea (OSA) and Non-Alcoholic Fatty Liver Disease (NAFLD), each associated with increased cardiovascular risk. This study aimed to determine the relationships between severity of OSA, degree of steatosis in NAFLD and cardiovascular risk via CIMT and atherosclerosis markers ie intracellular adhesion molecule-1 (ICAM-1) an Lipoprotein-a (Lp(a)) in a group of patients with OSA.

Materials and methods

This was a cross-sectional, single center study. A total of 110 subjects between 18 to 65 years of age and diagnosed with OSA following sleep study examinations were recruited. Exclusion criteria included seropositive Hepatitis B or Hepatitis C, and significant alcohol intake.

Result

The prevalence of NAFLD was 81.8%. The mean CIMT (0.08±0.03 vs 0.06±0.01 cm, p = 0.001), ICAM-1 (334.53±72.86 vs 265.46±102.92 ng/mL, p = 0.001) and Lp(a) (85.41±52.56 vs 23.55±23.66 nmol/L, p<0.001) were significantly higher in the NAFLD group compared to the non-NAFLD group. Comparisons between the different groups showed significantly increasing levels of CIMT, ICAM-1 and Lp(a), lowest within the non-NAFLD, followed by the NAFLD 1 and NAFLD 2+3 groups. There was a significant positive correlation between degree of steatosis and the severity of OSA (r = 0.453, p<0.001). Logistic regression analysis revealed that patients with apnea/hypopnea index (AHI) of >30 were 52.77 (CI 6.34, 439.14) times more likely to have NAFLD compared to those with mild AHI (p<0.001).

Conclusion

The prevalence of NAFLD is alarmingly high in this group of OSA patients. The degree of steatosis in patients with NAFLD was significantly correlated with severity of OSA, CIMT measurements, ICAM-1 and Lp(a). Our findings underscore screening for NAFLD in patients with OSA to ensure prompt risk stratification and management.

Association of acrylamide hemoglobin biomarkers with serum lipid levels in general US population: NHANES 2013-2016

The aim of present study was to investigate the association of acrylamide (AA) hemoglobin biomarkers and serum lipids level in a general population. Data set of our study were extracted from an open database - National Health and Nutrition Examination Surveys (NHANES) 2013-2016. In total 2899 participants were enrolled. The associations between AA hemoglobin parameters [hemoglobin adducts of AA (HbAA) and glycidamide (HbGA), total of HbAA and HbGA (HbAA+HbGA), and ratio of HbGA to HbAA (HbGA/HbAA)] and lipid levels [total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C)] were analyzed. Generalized linear models and restricted cubic spline plots were conducted to address the relationship between lipid levels and acrylamide markers. Comparing the lowest quantiles, HbGA and HbGA/HbAA both remained a significant trend regardless of lipid types. Analyses using a generalized linear model with restricted cubic spline and validated with regression models, all 4 AA parameters demonstrated a linear association and positive correlation with TG. Furthermore, there were also opposite nonlinear association between HbGA/HbAA and LDL-C (positive correlation), and HbGA/HbAA and HDL-C (negative correlation). Further analysis with threshold effect analysis or regression analysis showed HbGA and HbGA/HbAA remained significant association with all TC, TG, LDL-C, and HDL-C. The hemoglobin adducts AA parameters as long-term exposure biomarkers are associated with the atherosclerotic lipid changes in a population of US adults.

Lipoprotein(a) and Risk of Ischemic Stroke in the REGARDS Study

Objective- Increased Lp(a) [lipoprotein(a)] is associated with coronary heart disease risk, but links with stroke are less consistent. Blacks have higher Lp(a) levels and stroke incidence than whites but have been underrepresented in studies. We hypothesized that Lp(a) is a risk factor for ischemic stroke and that risk differs by race. Approach and Results- REGARDS (Reasons for Geographic and Racial Differences in Stroke) recruited 30 239 black and white US adults aged ≥45 in 2003-2007 to study regional and racial differences in stroke mortality. We measured baseline Lp(a) by immunonephelometric assay in 572 cases of incident ischemic stroke and a 967-person cohort random sample. The hazard ratio of stroke by baseline Lp(a) was calculated using Cox proportional hazards models, stratified by race. Lp(a) was modeled in sex- and race-specific quartiles, given known differences in distributions by race and sex. Interactions were tested by including interaction terms in the proportional hazards models, with P<0.10 considered statistically significant. After adjustment for age, sex, and stroke risk factors, being in the fourth versus the first Lp(a) quartile was weakly associated with ischemic stroke overall, hazard ratio, 1.45 (95% CI, 0.96-2.19). In blacks, the hazard ratio was 1.96 (95% CI, 1.10-3.46), whereas in whites HR was 1.14 (95% CI, 0.64-2.04); P interaction=0.12. Lp(a) was lower in men than women, but associations with stroke in men and women were similar. Conclusions- We confirm that Lp(a) is a risk factor for ischemic stroke. Further research is needed to confirm the role of racial differences of the Lp(a) risk multiplier in ischemic stroke.

Associations of plasma LP(a), Hcy and D-D levels with the subtype of ischemic cerebrovascular disease

The relevance of LP(a), Hcy, and D-D in ischemic cerebrovascular disease remains undefined. This study aimed to assess the associations of plasma LP(a), Hcy and D-D levels with the subtype of ischemic cerebrovascular disease.Patients with ischemic cerebrovascular disease admitted to the Taixing People's Hospital were retrospectively enrolled from November 2017 to July 2018. Immunoturbidimetry was used to assess 119 LAA, 107 SAO, and 112 TIA patients for plasma LP(a), Hcy, and D-D levels.Plasma LP(a), Hcy, and D-D levels in the large artery atherosclerosis (LAA) group were significantly lower than those of the transient ischemic attack (TIA) group (all P < .05). LP(a), Hcy, and D-D levels were significantly reduced in the SAO group compared with the TIA group (both P < .05). The LAA and SAO groups showed comparable values for all the above parameters (P > .05).LP(a), Hcy, and D-D levels differ according to the subtype of ischemic cerebrovascular disease.

Recurrent stroke: the role of thrombophilia in a large international pediatric stroke population

Risk factors for arterial ischemic stroke in children include vasculopathy and prothrombotic risk factors but their relative importance to recurrent stroke is uncertain. Data on recurrent stroke from databases held in Canada (Toronto), Germany (Kiel-Lübeck/Münster), and the UK (London/Southampton) were pooled. Data were available from 894 patients aged 1 month to 18 years at first stroke (median age, 6 years) with a median follow-up of 35 months. Among these 894 patients, 160 (17.9%) had a recurrence between 1 day and 136 months after the first stroke (median, 3.1 months). Among 288 children with vasculopathy, recurrence was significantly more common [hazard ratio (HR) 2.5, 95% confidence interval (95% CI) 1.92-3.5] compared to the rate in children without vasculopathy. Adjusting for vasculopathy, isolated antithrombin deficiency (HR 3.9; 95% CI: 1.4-10.9), isolated elevated lipoprotein (a) (HR 2.3; 95% CI: 1.3-4.1), and the presence of more than one prothrombotic risk factor (HR 1.9; 95% CI: 1.12-3.2) were independently associated with an increased risk of recurrence. Recurrence rates calculated per 100 person-years were 10 (95% CI: 3-24) for antithrombin deficiency, 6 (95% CI: 4-9) for elevated lipoprotein (a), and 13 (95% CI: 7-20) for the presence of more than one prothrombotic risk factor. Identifying children at increased risk of a second stroke is important in order to intensify measures aimed at preventing such recurrences.

Lipoprotein(a) and abdominal aortic aneurysm risk: The Atherosclerosis Risk in Communities study

BACKGROUND AND AIMS

No prospective study has investigated whether elevated lipoprotein(a) concentrations are associated with an increased risk of abdominal aortic aneurysm (AAA). We aimed to prospectively investigate this association.

METHODS

In 1987-1989, the Atherosclerosis Risk in Communities study measured plasma lipoprotein(a) in 13,683 participants aged 45-64 years, without a history of AAA surgery. We followed them for incident, clinical AAA events through 2011.

RESULTS

During the 272,914 person-years of follow-up, over a median of 22.6 years, we documented 505 incident AAA events. The age-, sex-, and race-adjusted model showed that individuals in the highest quintile of plasma lipoprotein(a) had an increased risk of AAA. Further adjustment for the other potential confounding factors, including other plasma lipids (high- and low-density lipoprotein cholesterol and triglyceride concentrations), attenuated the association, but individuals in the highest versus lowest quintile of plasma lipoprotein(a) still had a significantly increased risk of AAA [hazard ratio (95% confidence interval): 1.57 (1.19-2.08)]. Interaction testing suggested no difference in the associations for whites and African Americans (p for interaction = 0.96). A restricted cubic spline analysis demonstrated a positive dose-response relation of plasma lipoprotein(a) with AAA, with a steep increase in AAA risk above the 75th percentile (p for overall association = 0.0086, p for non-linear association = 0.097).

CONCLUSIONS

In this population-based cohort study, elevated lipoprotein(a) concentrations were independently associated with an increased risk of AAA. The association reflected a threshold of increased AAA risk at high lipoprotein(a) concentrations, rather than a steady monotonic association.

[Neonatal arterial ischemic stroke: Which thrombotic biological risk factors to investigate and which practical consequences?]

All biological risk factors that have been previously identified to increase the risk of thrombosis in adults, have also been studied in neonates with arterial Ischemic Stroke (NAIS), but most studies were retrospective and included relatively low numbers of affected children. We therefore could not suggest recommendations with a strong level of evidence and only expert proposals potentially useful for clinical practice will be presented in this text. Despite these limitations, the extensive analysis of published data supported that factor V Leiden (FVL) and increased levels of Lp(a) could be significant risk factors for NAIS. Importantly, these 2 risk factors cannot be considered as having provoked NAIS, and moreover, they do not influence the prognosis and the immediate treatment. However, since the FVL may have an impact for the prescription of a thromboprophylaxis when the neonate will become adult, to look for its presence in affected patients may be justified. For clinical practice, the following propositions can be applied: 1. Routine testing for thrombophilia (AT, PC PS deficiency, FV Leiden or FII20210A) or for detecting other biological risk factors such as antiphospholipid antibodies, high FVIII, homocystein or Lp(a) levels, MTHFR thermolabile variant, should not be considered in neonates with NAIS. 2. Testing for FV Leiden can be performed in case of documented family history of venous thromboembolic disease. 3. Testing neonates for the presence of antiphospholipid antibodies (APA) is mandatory in case of clinical events suggesting antiphospholipid syndrome in the mother (vascular thrombosis, and/or pregnancy morbidity). 4. Routine testing for thrombophilia is not proposed in both parents in case of early death of the neonate, apart from APA in the mother.

Lipoprotein(a) Levels and Recurrent Vascular Events After First Ischemic Stroke

Background and Purpose—

The association of elevated lipoprotein(a) (Lp(a)) levels and the incidence of cardiovascular disease, especially coronary heart disease and ischemic stroke, is well established. However, evidence on the association between Lp(a) levels and residual vascular risk in stroke survivors is lacking. We aimed to elucidate the risk for recurrent cardiovascular and cerebrovascular events in the patients with first-ever ischemic stroke with elevated Lp(a).

Methods—

All patients with acute ischemic stroke who participated in the prospective Berlin C&S study (Cream & Sugar) between January 2009 and August 2014 with available 12-month follow-up data and stored blood samples were eligible for inclusion. Lp(a) levels were determined in serum samples using an isoform-insensitive nephelometry assay. We assessed the risk for the composite vascular end point of ischemic stroke, transient ischemic attack, myocardial infarction, nonelective coronary revascularization, and cardiovascular death with elevated Lp(a) defined as >30 mg/dL using Cox regression analyses.

Results—

Of 465 C&S study participants, 250 patients were included into this substudy with a median National Institutes of Health Stroke Scale score of 2 (1–4). Twenty-six patients (10%) experienced a recurrent vascular event during follow-up. Among patients with normal Lp(a) levels, 11 of 157 subjects (7%) experienced an event at a median time of 161 days (interquartile range, 19–196 days), whereas in patients with elevated Lp(a) levels, 15 of 93 subjects (16%) experienced an event at a median time of 48 days (interquartile range, 9–194 days; P =0.026). The risk for a recurrent event was significantly higher in patients with elevated Lp(a) levels after adjustment for potential confounders (hazard ratio, 2.60; 95% confidence interval, 1.19–5.67; P =0.016).

Conclusions—

Elevated Lp(a) levels are associated with a higher risk for combined vascular event recurrence in patients with acute, first-ever ischemic stroke. This finding should be validated in larger, multicenter trials.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01378468.

Secondary Prevention of Ischemic Cerebrovascular Disease. What Is the Evidence?

Patients who had a transient ischemic attack or stroke are at increased risk of experiencing recurrent cerebrovascular events. For this reason, secondary prevention of ischemic cerebrovascular disease is essential. Several modifiable, lifestyle-associated risk factors have been implicated, such as physical activity, smoking, and alcohol consumption. Established and emerging vascular risk factors are associated with an increased risk of stroke. Pharmacologic treatment, including the use of antiplatelet, antihypertensive, and lipid-lowering agents, has also been shown to reduce the risk of secondary cerebrovascular events. Surgical intervention, either open or endovascular, may be the preferred therapeutic option in well-defined subsets of patients. It is important to establish specific measures for the early detection and prevention of recurrent cerebrovascular disease. Therefore, further research and greater awareness in this field are needed.

Fractions of Total Plasma Homocysteine in Patients with Ischemic Stroke Before the Age of 55 Years

The mechanism responsible for the association between elevated circulating homocysteine levels and ischemic stroke remains unclear. Therefore, the authors assessed total plasma homocysteine (tHcy) and its fractions (free [fHcy] and protein-bound [bHcy] homocysteine) in patients with ischemic stroke before the age of 55 years. Fifty patients (23 men, mean age 46.8 ±7.6 years) with ischemic stroke or transient ischemic attacks, with symptoms lasting <72 hours were enrolled. In this group: 32 (64%) patients had hypertension; 12 (24%), ischemic heart disease (IHD); and 20 (40%), type 2 diabetes mellitus (DM). The control group consisted of 30 matched healthy individuals (17 men, mean age 44.6 ±6.2 years). The tHcy, fHcy, and bHcy levels were determined by high-performance liquid chromatography. tHcy and its fractions did not differ significantly between patients and controls. However, stroke patients with hypertension had significantly higher concentrations of tHcy and bHcy compared to stroke patients without hypertension (tHcy 13.0 ±3.3 vs 10.7 ±3.2 µmol/L, p<0.05; bHcy 9.7 ±2.6 vs 7.8 ±2.3 µmol/L, p<0.01, respectively); fHcy was borderline significant: 3.1 (1.5-6.5) vs 2.5 (1.8-5.3) µmol/L, p=0.05. The presence of IHD, DM, hyperlipoproteinemia, clinical subtypes of stroke, smoking, and family history of stroke did not influence these parameters. In the group of 50 patients, tHcy correlated with mean systolic blood pressure (BP) ( r =0.3, p<0.05) and bHcy correlated with mean systolic and mean diastolic BP ( r =0.3, p<0.05). These findings suggest an association between hypertension and redox status of Hcy in patients with ischemic stroke before the age of 55 years. This observation supports the hypothesis that elevated BP may contribute to Hcy-related vascular injury.

Effect of Fenofibrate on Serum Inflammatory Markers in Patients With High Triglyceride Values

Background: Atherosclerosis is the leading cause of death in developed countries. Although the mechanisms that underlie this process are not well defined, it has been proposed that atherosclerosis is mainly an inflammatory disease. In this context, a number of inflammatory markers have been studied for their ability to predict future cardiovascular events in asymptomatic individuals or patients with established atherosclerotic disease.

Methods and Results: The aim of our study was to evaluate the effect of micronized fenofibrate on serum inflammatory markers, such as C-reactive protein, fibrinogen, and plasma platelet-activating factor acetylhydrolase (PAF-AH) in patients with high triglyceride values. An analysis of baseline values revealed that hypertriglyceridemic patients (n = 58) exhibit an atherogenic phenotype, characterized not only by elevated lipid values but also by high concentrations of serum inflammatory markers. Along with the improvement in serum lipid profile (reduction in triglycerides and total cholesterol, low-density lipoprotein, and nonhigh-density lipoprotein-cholesterol, with a concomitant increase in high-density lipoprotein-cholesterol levels), fenofibrate administration significantly reduced the values of serum inflammatory markers by 34%, 9.5%, and 24.8% for C-reactive protein, fibrinogen, and plasma PAF-AH, respectively. However, with the exception of PAF-AH, these reductions in inflammatory markers were not correlated with the changes in lipid values.

Conclusions: In addition to its well-known hypolipidemic effects, fenofibrate may also possess significant anti-inflammatory properties that can contribute its antiatherogenic effect.

Lipoprotein (a) as a risk factor for ischemic stroke: a meta-analysis

OBJECTIVE

Lipoprotein (a) [Lp(a)] harbors atherogenic potential but its role as a risk factor for ischemic stroke remains controversial. We conducted a meta-analysis to determine the relative strength of the association between Lp(a) and ischemic stroke and identify potential subgroup-specific risk differences.

METHODS

A systematic search using the MeSH terms "lipoproteins" OR "lipoprotein a" AND "stroke" was performed in PubMed and ScienceDirect for case-control studies from June 2006 and prospective cohort studies from April 2009 until December 20th 2014. Data from eligible papers published before these dates were reviewed and extracted from previous meta-analyses. Studies that assessed the relationship between Lp(a) levels and ischemic stroke and reported generic data-i.e. odds ratio [OR], hazard ratio, or risk ratio [RR]-were eligible for inclusion. Studies that not distinguish between ischemic and hemorrhagic stroke and transient ischemic attack were excluded. Random effects meta-analyses with mixed-effects meta-regression were performed by pooling adjusted OR or RR.

RESULTS

A total of 20 articles comprising 90,904 subjects and 5029 stroke events were eligible for the meta-analysis. Comparing high with low Lp(a) levels, the pooled estimated OR was 1.41 (95% CI, 1.26-1.57) for case-control studies (n = 11) and the pooled estimated RR was 1.29 (95% CI, 1.06-1.58) for prospective studies (n = 9). Sex-specific differences in RR were inconsistent between case-control and prospective studies. Study populations with a mean age of ≤55 years had an increased RR compared to older study populations. Reported Lp(a) contrast levels and ischemic stroke subtype significantly contributed to the heterogeneity observed in the analyses.

CONCLUSION

Elevated Lp(a) is an independent risk factor for ischemic stroke and may be especially relevant for young stroke patients. Sex-specific risk differences remain conflicting. Further studies in these subgroups may be warranted.

Evaluation of the Hypoglycemic Properties of Anacardium humile Aqueous Extract

The antihyperglycemic effects of several plant extracts and herbal formulations which are used as antidiabetic formulations have been described and confirmed to date. The main objective of this work was to evaluate the hypoglycemic activity of the aqueous extract of Anacardium humile. Although the treatment of diabetic animals with A. humile did not alter body weight significantly, a reduction of the other evaluated parameters was observed. Animals treated with A. humile did not show variation of insulin levels, possibly triggered by a mechanism of blood glucose reduction. Levels of ALT (alanine aminotransferase) decreased in treated animals, suggesting a protective effect on liver. Levels of cholesterol were also reduced, indicating the efficacy of the extract in reestablishing the balance of nutrients. Moreover, a kidney protection may have been achieved due to the partial reestablishment of blood glucose homeostasis, while no nephrotoxicity could be detected for A. humile. The obtained results demonstrate the effectiveness of A. humile extracts in the treatment of alloxan-induced diabetic rats. Therefore, A. humile aqueous extract, popularly known and used by diabetic patients, induced an improvement in the biochemical parameters evaluated during and following treatment of diabetic rats. Thus, a better characterization of the medicinal potential of this plant will be able to provide a better understanding of its mechanisms of action in these pathological processes.

Lipoprotein(a) in cardiovascular diseases

Lipoprotein(a) (Lp(a)) is an LDL-like molecule consisting of an apolipoprotein B-100 (apo(B-100)) particle attached by a disulphide bridge to apo(a). Many observations have pointed out that Lp(a) levels may be a risk factor for cardiovascular diseases. Lp(a) inhibits the activation of transforming growth factor (TGF) and contributes to the growth of arterial atherosclerotic lesions by promoting the proliferation of vascular smooth muscle cells and the migration of smooth muscle cells to endothelial cells. Moreover Lp(a) inhibits plasminogen binding to the surfaces of endothelial cells and decreases the activity of fibrin-dependent tissue-type plasminogen activator. Lp(a) may act as a proinflammatory mediator that augments the lesion formation in atherosclerotic plaques. Elevated serum Lp(a) is an independent predictor of coronary artery disease and myocardial infarction. Furthermore, Lp(a) levels should be a marker of restenosis after percutaneous transluminal coronary angioplasty, saphenous vein bypass graft atherosclerosis, and accelerated coronary atherosclerosis of cardiac transplantation. Finally, the possibility that Lp(a) may be a risk factor for ischemic stroke has been assessed in several studies. Recent findings suggest that Lp(a)-lowering therapy might be beneficial in patients with high Lp(a) levels. A future therapeutic approach could include apheresis in high-risk patients in order to reduce major coronary events.

Correlative study between neuron-specific enolase and blood sugar level in ischemic stroke patients

Background:

A study to investigate the level of the neurobiochemical marker, Neuron-Specific Enolase (NSE), at the time of admission and its correlation with the blood sugar level in ischemic stroke patients.

Patients and Methods:

We investigated 90 patients with complete stroke who were admitted to the Stroke Unit of the Department of Neurology at Sri Aurobindo Institute of Medical Sciences. NSE was measured with commercially available quantitative ‘sandwich’ enzyme-linked immunosorbent assay kits obtained from R and D Systems. Hyperglycemia was defined as blood glucose concentration ≥ 7 mmol / L, and measured using the glucose oxidase method immediately.

Results:

Significantly increased NSE and lipid profile levels were found in ischemic stroke patients as compared to the control. Hyperglycemic ischemic stroke patients had increased levels of NSE, lipid profile, and National Institute of Health stroke scale scores (NIHSS score) compared to normoglycemic ischemic stroke patients. In addition the serum NSE level of hyperglycemic stroke patients was also positively correlated with the blood sugar level (r = 0.734 P < 0.001).

Conclusions:

Hyperglycemia predicts an increased risk of poor outcome after ischemic stroke and it is reflected by a significantly increased level of Neuron-Specific Enolase.

Lipoprotein (a) and other Lipid Profile in Patients with Thrombotic Stroke: Is it a Reliable Marker?

BACKGROUND

Cerebrovascular disease (CVD) and coronary heart disease (CHD) cause 40%-50% of deaths in developed countries with CVD causing 10%-12% of deaths. Though increased Lipoprotein (a) is a risk factor in developing CHD, its role is poorly defined in etiopathogenesis of CVD.

AIMS

To find the association of lipoprotein (a) and lipid profile in thrombotic stroke patients after acute phase.

SETTINGS AND DESIGN

The study was conducted at Kasturba Medical College, Manipal. Twenty one cases of thrombotic stroke and 18 cases of age and sex matched controls were taken for the study. Informed consent was taken from both case and control.

MATERIALS AND METHODS

Overnight fasting sample was collected from both case and control. Serum was separated and parameters such as total cholesterol, triglycerides, high density lipoproteins-C, low density lipoprotein-C, lipoprotein (a), fasting blood sugars were estimated.

STATISTICAL ANALYSIS

Data were analyzed by SPSS software, Student's t-test, standard deviation (SD), and standard error of mean (SEM), P-value <0.05 is considered to be significant.

RESULTS

In this study, we found no statistical significant differences in serum lipid and lipoprotein (a) profile between controls and thrombotic stroke patients.

CONCLUSIONS

Highest frequency (38%) of stroke was found in the age group of 7080 years. There were other associated risk factors such as diabetes in five cases (24%), hypertension in nine cases (43%), and family history of stroke in four cases. However, further studies are required to evaluate the importance of serum Lp(a) estimation in the assessment as a risk factor for thrombotic stroke.

Biomarkers of asymptomatic carotid stenosis in patients undergoing coronary artery bypass grafting

BACKGROUND AND PURPOSE

Carotid artery stenosis is an important etiologic factor of stroke related to coronary artery bypass surgery. We evaluated clinical and laboratory factors to identify biomarkers for pre-existing carotid artery stenosis in patients undergoing coronary artery bypass surgery.

METHODS

Between June 2006 and September 2008, 811 patients aged ≥50 years underwent preoperative carotid artery duplex scanning as part of a preoperative assessment for nonemergency cardiac procedures. Of these, 54 patients with previous stroke or transient ischemic attack were excluded. The association between various biomarkers and carotid artery stenosis was analyzed by multiple logistic regression analysis. The receiver operating characteristic curves were generated and analyzed to compare diagnostic performance and optimum diagnostic cutoff levels of biomarkers.

RESULTS

A total of 757 patients was included in the study. The prevalence of asymptomatic carotid stenosis of ≥50% and ≥70% was 26.4% and 8.6%, respectively. In multivariate analysis, plasma levels of apolipoprotein B (apoB):apoA-I, lipoprotein(a), and homocysteine were independently associated with carotid stenosis of ≥50%: the OR (95% CI) for apoB/apoA-I, lipoprotein(a), and homocysteine in the highest versus lowest quartile was 2.07 (1.18 to 3.66), 2.17 (1.16 to 4.05), and 2.13 (1.20 to 3.79), respectively. Receiver operating characteristic curve analysis indicated area under the curve values of 0.708 (apoB:apoA-I), 0.678 (lipoprotein[a]), and 0.689 (homocysteine). The sensitivity, specificity, positive and negative predictive values (%) for diagnosis of carotid stenosis ≥50% were 80.0, 50.4, 38.0, and 86.9 for apoB:apoA-I; 47.0, 78.9, 46.1, and 79.5 for lipoprotein(a); and 69.3, 62.1, 41.2, and 84.1 for homocysteine, respectively.

CONCLUSIONS

Our findings indicated that plasma levels of apoB/apoA-I, lipoprotein(a), and homocysteine can predict asymptomatic carotid stenosis in patients undergoing coronary artery bypass surgery.

Lipoprotein a: where are we now?

PURPOSE OF REVIEW

To provide an update of the literature describing the link between lipoprotein a and vascular disease.

RECENT FINDINGS

There is evidence that elevated plasma lipoprotein a levels are associated with coronary heart disease, stroke and other manifestations of atherosclerosis. Several mechanisms may be implicated, including proinflammatory actions and impaired fibrinolysis.

SUMMARY

Lipoprotein a potentially represents a useful tool for risk stratification in the primary and secondary prevention setting. However, there are still unresolved methodological issues regarding the measurement of lipoprotein a levels. Targeting lipoprotein a in order to reduce vascular risk is hampered by the lack of well tolerated and effective pharmacological interventions. Moreover, it has not yet been established whether such a reduction will result in fewer vascular events. The risk attributed to lipoprotein a may be reduced by aggressively tackling other vascular risk factors, such as low-density lipoprotein cholesterol.

Lipoprotein(a) predicts progression of carotid artery intima-media thickening in patients with type 2 diabetes: A four-year follow-up

BACKGROUND

The aim of the study was to establish whether increased levels of serum lipoprotein(a) significantly contribute to an increase in intima-media thickness and the number of carotid artery plaques, and consequently to cardiovascular risk in patients with type 2 diabetes mellitus.

METHODS

Lipoprotein(a) levels, intima-media thickness and the number of carotid artery plaques were determined at the beginning of the study in 146 patients with type 2 diabetes. Patients were divided into two groups according to serum lipoprotein(a) levels (> or <or=30 mg/dl). Intima-media thickness and the number of plaques were again determined after four years of follow-up. Intima-media thickness was assessed using high-resolution B-mode ultrasound.

RESULTS

The two groups of patients revealed no significant differences in baseline intima-media thickness (P = 0.112) in relation to lipoprotein(a) level. After follow-up, intima-media thickness was significantly greater in patients with higher lipoprotein(a) levels (1.24 + 0.22 vs. 1.15 + 0.17 mm, respectively; P = 0.005). The mean increase in thickness over four years was 0.12 mm (0.030 mm/year) in the group with low lipoprotein(a) levels and 0.17 mm (0.043 mm/year) in the group with high lipoprotein(a). Multivariate analysis indicated that intima-media thickness depended on lipoprotein(a), and not on triglyceride, HDL-cholesterol levels or waist-to-hip ratio. No significant difference in baseline and follow-up number of plaques was observed between the study groups (P = 0.276 vs. P = 0.355, respectively). Although the group with lipoprotein(a) >30 mg/dl had more cardiovascular events, the difference was not statistically significant.

CONCLUSIONS

These results indicate that lipoprotein(a) is an independent, genetically determined risk factor closely associated with progression of intima-media thickness in type 2 diabetes.

Epidemiology of ischemic and hemorrhagic stroke: incidence, prevalence, mortality, and risk factors

The epidemiology of ischemic and hemorrhagic stroke is an ongoing exploration to identify risk factors that continue to expand with the advent of technological advancements and preventative medical practices. Identification of risk factors that can or cannot be modified is a crucial step in determining stroke risk. Many of the modifiable risk factors are well established, and specific interventions to reduce stroke risk have been established. Some risk factors are less established, and intervention to reduce risk is yet to be determined by evidence-based medicine. Data from ongoing randomized clinical trials continue to enhance our ability to prevent a first stroke.

Cardiovascular biomarkers: increasing impact of laboratory medicine in cardiology practice

The practice of cardiology is in continual evolution, in parallel with the progress achieved by medical research in understanding the pathophysiology of cardiovascular disease and in developing new therapeutic procedures. Consequently, manufacturers of cardiac biomarkers are pressed with new demands to improve the performance of the existing and the development of novel ones. Several highly sensitive and/or specific assays for myocardial ischemic damage and myocardial function detection have already become commercially available. Moreover, an increasing number of novel risk factors have been added to the classical risk factors of cardiovascular disease. Finally, the recent surge of genetic analysis procedures will likely soon provide the clinical cardiologist with a number of laboratory tests for defining the molecular diagnosis, assessing new risk factors, and better targeting the pharmaceutical approaches in patients with cardiovascular disease. In this review, we first present the general characteristics of a biomarker followed by the analytical and clinical performance of assay methods.

Vascular risk factors in South Asians

South Asians originate from the Indian sub-continent (India, Pakistan, Bangladesh, Sri Lanka and Nepal) and represent one fifth of the world's population. Several studies suggested that South Asians have an increased risk of developing coronary heart disease (CHD) when compared with European populations. We review the role of traditional and emerging risk factors in the increased CHD risk in South Asians. The high prevalence of insulin resistance and type 2 diabetes mellitus in South Asians may be a major cause for their elevated vascular risk. However, other established and emerging risk factors are also overrepresented in South Asians. Large-scale prospective studies could determine the relative contribution of established and emerging vascular risk factors in South Asians. There is an urgent need for trials in South Asians that will evaluate clinical outcomes following treatment of these risk factors.

Vascular risk factors, cognitive decline, and dementia

Dementia is one of the most important neurological disorders in the elderly. Aging is associated with a large increase in the prevalence and incidence of degenerative (Alzheimer's disease) and vascular dementia, leading to a devastating loss of autonomy. In view of the increasing longevity of populations worldwide, prevention of dementia has turned into a major public health challenge. In the past decade, several vascular risk factors have been found to be associated with vascular dementia but also Alzheimer's disease. Some longitudinal studies, have found significant associations between hypertension, diabetus mellitus, and metabolic syndrome, assessed at middle age, and dementia. Studies assessing the link between hypercholesterolemia, atrial fibrillation, smoking, and dementia have given more conflicting results. Furthermore, some studies have highlighted the possible protective effect of antihypertensive therapy on cognition and some trials are evaluating the effects of statins and treatments for insulin resistance. Vascular risk factors and their treatments are a promising avenue of research for prevention of dementia, and further long-term, placebo-controlled, randomized studies, need to be performed.

Different apoprotein(a) isoform proportions in serum and carotid plaque

INTRODUCTION

Cardio- and/or cerebro-vascular risk are associated with high lipoprotein (a) [Lp(a)] levels and low-molecular-weight (LMW) apo(a) isoforms. Aims of this study were to evaluate the deposition of apo(a) isoforms and apoprotein B (apo B) in atherosclerotic plaque from patients (males and females) who had carotid endarterectomy for severe stenosis, and to identify differences between patients classified by gender and divided according to the stability or instability of their plaques.

MATERIALS AND METHODS

We determined lipids, apo B and Lp(a) in serum and plaque extracts from 55 males and 25 females. Apo(a) was phenotyped and isoforms were classified by number of kringle IV (KIV) repeats.

RESULTS

Lp(a) levels were higher in female serum and plaque extracts than in male samples, while apo B levels were lower. More Lp(a) than apo B deposition was observed in plaque after normalization for serum levels. Thirty-one different apo(a) isoforms were detected in our patients, with a double band phenotype in 94% of cases. In both sexes, the low/high (L/H) molecular weight apo(a) isoform expression ratio was significantly higher in plaque than in serum. Females with unstable plaques had higher Lp(a) levels in both serum and tissue extracts, and fewer KIV repeats of the principal apo(a) isoform in the serum than the other female group or males.

CONCLUSIONS

In both sexes, the same apo(a) isoforms are found in serum and atherosclerotic plaque, but in different proportions: in plaque, LMW apo(a) is almost always more strongly accumulated than HMW apo(a), irrespective of any combination of apo(a) isoforms in double band phenotypes or Lp(a) serum levels. Moreover, serum and tissue Lp(a) levels were higher in females than in males, and particularly in the group with unstable plaques.

The role of established and emerging risk factors in peripheral vascular graft occlusion

Several studies have evaluated the association between established as well as emerging vascular risk factors with peripheral graft occlusion. There is evidence for a link between the risk for graft occlusion and total serum cholesterol, low-density lipoprotein cholesterol and triglyceride levels. The overall effect of smoking shows a 2.35-fold increase in risk of graft failure. Studies involving diabetic patients undergoing peripheral bypass may have failed to detect higher occlusion rates, possibly due to increased morbidity and mortality as well as higher amputation rates even if the graft is patent. Both antiplatelet agents and anticoagulation seem to be effective in the prevention of graft occlusion. Unconvincing data have been published with regards to the effect of hypertension on graft patency. Emerging factors such as fibrinogen, lipoprotein (a), C-reactive protein and homocysteine levels should also be considered when assessing the risk of graft occlusion. More research is needed to prevent graft occlusion due to the obvious clinical relevance, quality of life and cost issues.

Relative Value of Inflammatory, Hemostatic, and Rheological Factors for Incident Myocardial Infarction and Stroke

Background— The aim of our present study was to compare the association of a wide range of 17 biomarkers of inflammation, hemostasis, and blood rheology with incident heart disease and stroke after accounting for an indicator of subclinical atherosclerotic disease and traditional risk factors and also to determine their incremental predictive ability.

Methods and Results— We used data from the Edinburgh Artery Study, a population cohort study started in 1987 that comprised 1592 men and women aged 55 to 74 years. Subjects were followed for a mean of 17 years, and 416 of them suffered at least 1 cardiovascular event. In analyses adjusted for cardiovascular risk factors and history of cardiovascular disease (CVD): C-reactive protein, interleukin-6, fibrinogen, fibrin D-dimer, tissue plasminogen activator (t-PA), leukocyte elastase, and lipoprotein(a) (all P <0.01), as well as von Willebrand factor and plasma viscosity (both P <0.05), had significant hazard ratios for incident CVD. Further adjustment for a measure of subclinical atherosclerosis (ankle brachial index) had little impact on these associations. The hazard ratios (95% CI) for incident CVD between top and bottom tertiles in the latter analysis were 1.78 (1.30 to 2.45) for C-reactive protein, 1.85 (1.33 to 2.58) for interleukin-6, and 1.76 (1.35 to 2.31) for fibrinogen. Single biomarkers provided little additional discrimination of incident CVD to that obtained from cardiovascular risk factors and the ankle brachial index. An incremental score of multiple markers [interleukin-6, t-PA, intercellular adhesion molecule 1, and lipoprotein(a)] provided some added discrimination.

Conclusions— Several “novel” risk factors predicted CVD after adjustments for conventional risk factors and also for a measure of asymptomatic disease. However, their incremental predictive ability was modest and their clinical utility remains uncertain.

Lipoprotein (a) and risk of ischemic stroke in young adults

Lipoprotein (a) [Lp(a)] is a LDL-particle linked to apoprotein (a) [apo(a)]. High Lp(a) plasma level is a risk factor for coronary heart disease and, in older men, for ischemic stroke. The role of Lp(a) as a risk factor for ischemic stroke in young adults is uncertain.

METHODS

Lp(a) concentration was prospectively measured in 100 consecutive patients with acute ischemic stroke (58 men and 42 women) aged 18-55 years, and in 100 controls matched for age and gender.

RESULTS

The distribution of Lp(a) concentration was skewed toward the highest and median tertiles in male patients. In multivariate logistic regression analyses adjusting on classical risk factors for ischemic stroke and lipid variables, Lp(a) concentration in the highest and medium tertiles compared with the lowest tertile was significantly associated with ischemic stroke in men (OR 3.55, 95% CI 1.33-9.48, p = 0.012), but was not in women (OR 0.42, 95% CI 0.14-1.26, p = 0.12). Although large vessel atherosclerosis was more common in men than in women, there were no differences in Lp(a) concentration according to the cause of ischemic stroke.

CONCLUSION

Among subjects aged 18-55 years, a slightly elevated Lp(a) concentration was strongly and independently associated with ischemic stroke in men, but not in women. Further studies are required to elucidate the mechanisms underlying this gender-specific association.

Lp(a) lipoprotein and plasminogen activity in patients with different etiology of ischemic stroke

BACKGROUND AND PURPOSE

Lp(a) lipoprotein plays an important part in atherothrombogenesis and is considered an independent risk factor for coronary heart disease. However, its role in cerebrovascular disease remains unclear, in particular because of the heterogeneous nature of strokes. We investigated whether elevated Lp(a) is more frequent in ischemic stroke related to atherothrombosis than in other etiologies of stroke. Because of the close structural homology between Lp(a) and plasminogen, we also studied the role of plasminogen in different stroke subtypes and whether there is a dependency on Lp(a) plasma levels.

METHODS

Lp(a) levels and plasminogen activity were measured in 253 consecutive patients with acute ischemic stroke and in 63 controls (CS). Subtypes of stroke were established according to the TOAST criteria.

RESULTS

Median Lp(a) levels were found to be higher in the total cerebral infarction group and in patients with large artery atherosclerosis (LAA) when compared with CS (20.9 and 22.0 mg/dl, respectively, vs. 16.0 mg/dl; p < 0.05). In addition, elevated Lp(a) levels >30 mg/dl were more frequent among the LAA subgroup than among CS (39.4 vs. 11.1%; p < 0.001). Mean plasminogen activity was lower in the total cerebral infarction group (110.8 vs. 120.3%; p < 0.001) and in patients with cardioembolic stroke (109.8 vs. 120.3%; p < 0.05) when compared with CS. There was no correlation between Lp(a) levels and plasminogen activity.

CONCLUSIONS

Our results support the hypothesis that elevated Lp(a) is a risk factor for ischemic stroke and especially for strokes caused by LAA. Low plasminogen activity may play a role in the pathogenesis of cerebrovascular disease, especially for the development of cardioembolic stroke.

Non-low-density lipoprotein cholesterol-associated actions of ezetimibe: an overview

Ezetimibe, an intestinal cholesterol absorption inhibitor, lowers circulating low-density lipoprotein cholesterol (LDL-C) levels both when administered as monotherapy and in combination with other hypolipidaemic drugs, mostly statins. This review focuses on the effects of ezetimibe on non-LDL-C-associated variables. In most studies, ezetimibe effectively reduced triglyceride and increased high density lipoprotein cholesterol levels. The authors also consider the effect of ezetimibe on other variables such as C-reactive protein levels, insulin sensitivity and endothelial function. Ezetimibe is useful in patients with sitosterolaemia (a rare inherited disorder) as it significantly reduces plasma phytosterol concentrations. Ezetimibe fulfils two of the three essential characteristics of any drug (efficacy and safety). However, clinical studies are required to provide evidence of its ability to reduce vascular events.

Serum lipoprotein(a) levels and apolipoprotein(a) isoform size and risk for first-ever acute ischaemic nonembolic stroke in elderly individuals

In a population-based case-control study, we investigated the association of acute ischaemic stroke with lipoprotein(a) (Lp(a)) levels and apolipoprotein (Apo) (a) isoform size in subjects aged older than 70 years. A total of 163 patients with a first-ever-in-a-lifetime acute ischaemic/nonembolic stroke and 166 controls were included. Compared to controls, stroke patients exhibited higher Lp(a) concentrations (median value, 12.2 mg/dl versus 6.4 mg/dl, p < 0.001) and a higher frequency of small Apo(a) isoforms (44.2% versus 29.5%, p < 0.01). Multivariate logistic regression analysis showed a significant association of acute ischaemic stroke with Lp(a) levels [adjusted odds ratio (OR), 1.37, 95% CI (1.12-1.67); p = 0.002], and small Apo(a) isoform size [OR, 1.74 (1.10-3.03); p = 0.04]. Compared to subjects with Lp(a) levels in the lowest quintile, those within the highest quintile had a 3.2-times adjusted risk to suffer an acute ischaemic/nonembolic stroke (1.60-6.62, 95% CI; p < 0.001). Furthermore, analysis of interaction between lipid variables revealed that in the presence of elevated Lp(a) levels the inverse relationship between HDL-cholesterol levels and ischaemic stroke was negated [OR, 1.01 (1.00-1.03); p = 0.015]. Our study suggests that determination of Lp(a) levels and Apo(a) isoform size may be important in identifying elderly individuals at risk of ischaemic stroke independently of other risk factors and concurrent metabolic derangements.

Primary Prevention of Ischemic Stroke

Background and Purpose— This guideline provides an overview of the evidence on various established and potential stroke risk factors and provides recommendations for the reduction of stroke risk.

Methods— Writing group members were nominated by the committee chair on the basis of each writer’s previous work in relevant topic areas and were approved by the American Heart Association Stroke Council’s Scientific Statement Oversight Committee. The writers used systematic literature reviews (covering the time period since the last review published in 2001 up to January 2005), reference to previously published guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and when appropriate, formulate recommendations based on standard American Heart Association criteria. All members of the writing group had numerous opportunities to comment in writing on the recommendations and approved the final version of this document. The guideline underwent extensive peer review before consideration and approval by the AHA Science Advisory and Coordinating Committee.

Results— Schemes for assessing a person’s risk of a first stroke were evaluated. Risk factors or risk markers for a first stroke were classified according to their potential for modification (nonmodifiable, modifiable, or potentially modifiable) and strength of evidence (well documented or less well documented). Nonmodifiable risk factors include age, sex, low birth weight, race/ethnicity, and genetic factors. Well-documented and modifiable risk factors include hypertension, exposure to cigarette smoke, diabetes, atrial fibrillation and certain other cardiac conditions, dyslipidemia, carotid artery stenosis, sickle cell disease, postmenopausal hormone therapy, poor diet, physical inactivity, and obesity and body fat distribution. Less well-documented or potentially modifiable risk factors include the metabolic syndrome, alcohol abuse, drug abuse, oral contraceptive use, sleep-disordered breathing, migraine headache, hyperhomocysteinemia, elevated lipoprotein(a), elevated lipoprotein-associated phospholipase, hypercoagulability, inflammation, and infection. Data on the use of aspirin for primary stroke prevention are reviewed.

Conclusion— Extensive evidence is available identifying a variety of specific factors that increase the risk of a first stroke and providing strategies for reducing that risk.

Lipoprotein(a) and incident ischemic stroke: the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND PURPOSE

Numerous case-control and cross-sectional studies have reported higher median lipoprotein(a) [Lp(a)] levels among stroke patients than controls, but existing prospective studies have not consistently shown an association. We sought to examine the relationship between plasma Lp(a) levels and the incidence of ischemic stroke among blacks and whites.

METHODS

Between 1987 and 1989, 14,221 men and women (3647 blacks and 10,574 whites) aged 45 to 64 years and free of clinical cardiovascular disease, took part in the first examination of the Atherosclerosis Risk in Communities (ARIC) study cohort. Lp(a) and other risk factors for cardiovascular disease were measured at baseline.

RESULTS

During the 13.5-year follow-up, 496 ischemic strokes occurred. Participants with Lp(a) > or =300 microg/mL had a 79% higher age, sex, and race-adjusted rate ratio (RR) of ischemic stroke than did those with Lp(a) levels <100 microg/mL. Compared with Lp(a) <100 microg/mL, the multivariate adjusted RRs for Lp(a) > or =300 microg/mL were 1.84 (95% CI, 1.05 to 3.07) in black women, 1.72 (95% CI, 0.86 to 3.48) in black men, 2.42 (95% CI, 1.30 to 4.53) in white women, and 1.18 (95% CI, 0.47 to 2.90) in white men. There was no significant increment in the RRs for 100 to 199 microg/mL and 200 to 299 microg/mL groups.

CONCLUSIONS

A high Lp(a) concentration is associated with a higher incidence of ischemic stroke in blacks and white women, but not in white men.

Circulating biomarkers of cognitive decline and dementia

Plasma and serum biochemical markers proposed for cognitive decline of degenerative (Alzheimer's disease, AD) or vascular origin and predementia syndromes (mild cognitive impairment and other related entities) are based on pathophysiologic processes such as lipoprotein metabolism (total cholesterol, apolipoprotein E, 24S-hydroxy-cholesterol), and vascular disease (homocysteine, lipoprotein(a)); SP formation (amyloid beta(Abeta)-protein, Abeta autoantibodies, platelet APP isoforms), oxidative stress (isoprostanes, vitamin E), and inflammation (cytokines). This review will focus on the current knowledge on circulating serum and plasma biomarkers of cognitive decline and dementia that are linked to cholesterol homeostasis and lipoprotein abnormalities, senile plaque formation and amyloid precursor protein (APP) metabolism, oxidative stress, and inflammatory reactions. Special emphasis will, however, be placed on biomarkers related to lipoprotein metabolism and vascular disease. Analytically, most plasma and serum proteins or metabolites lack reproducibility, sensitivity, or specificity for the diagnosis, risk and progression assessment, or therapeutic monitoring of AD and other dementing disorders. Measures linked to lipoprotein metabolism and vascular disease, APP metabolism, oxidative stress, or inflammation appear altered in AD relative to controls, but lack sufficient discriminatory power. Measures combining several biomarkers or incorporating a range of proteins in plasma and small molecule metabolites are promising approaches for the development of plasma or serum-based diagnostic tests for AD and other dementing disorders, as well as for predementia syndromes.

Lipid metabolism in cognitive decline and dementia

This review will focus on the current knowledge on circulating serum and plasma risk factors of cognitive decline of degenerative (Alzheimer's disease, AD) or vascular origin (vascular dementia, VaD) linked to cholesterol homeostasis and lipoprotein disturbances, i.e. total cholesterol (TC), 24S-hydroxy-cholesterol, lipoprotein(a) (Lp(a)), or apolipoprotein E (APOE). These measures linked to lipoprotein metabolism appear to be altered in AD, VaD, or predementia syndrome relative to controls, but with contrasting results. At present, several studies have demonstrated the dependence of APOE serum levels upon the APOE genotype, nonetheless serum APOE levels seems not to be a credible risk factor or a biochemical marker for AD instead of APOE genotyping. In fact, there was no consistent association of serum or plasma apoE protein levels with the disease when controlled for APOE genotype. In addition, there are some evidence that higher Lp(a) levels could be linked with AD, although there are studies suggesting an increased presence of low molecular weight apo(a) in AD, VaD, and frontotemporal dementia, that are associated with elevated Lp(a) levels. In fact, the apo(a) gene is highly polymorphic in length due to variation in the numbers of a sequence encoding the apo(a) kringle 4 domain, and plasma levels of Lp(a) are inversely correlated with apo(a) size. Furthermore, although serum/plasma levels of TC and 24S-hydroxycholesterol are not credible diagnostic markers for AD and cognitive decline, the current evidence suggests that they may be modifiable risk/protective factors. The prevailing wisdom is that high TC is a risk factor for dementia. However, the relationship between TC and dementia may vary considerably depending on when cholesterol is measured over the life course or, alternatively, in relation to the underlying course of the disease. Several observational studies have suggested that statins, which are effective in lowering cholesterol, may reduce the risk of dementia, but the results of these reports are inconclusive. Thus, more studies with long-term follow-up and serial assessments of TC are needed to further clarify the causal relationship between cholesterol and dementia.

Effects of oestrogen receptor-active compounds on lipid metabolism

Selective estrogen receptor modulators (SERMs) have been used successfully in the treatment of breast cancer and osteoporosis while Tibolone has been used extensively in Europe for the treatment of menopausal symptoms. Limited data is available on the effect of these agents on the cardiovascular system. Traditional and novel lipid markers are valuable in determining patients at increased cardiovascular risk. The purpose of this article is to discuss the mechanism of action of Tamoxifen, Raloxifene and Tibolone and their effects on lipid metabolism.

Prothrombotic factors in children with stroke or porencephaly

OBJECTIVE

This study compared the frequencies of genetic and functional coagulation abnormalities in children with arterial ischemic stroke or porencephaly with frequencies in previously published studies.

METHODS

A series of 59 children (age 0-18 years) with arterial ischemic stroke or porencephaly were referred to the National Institutes of Health. A blood sample, buccal smear sample, questionnaire, and pedigree were requested for each child. Blood samples were analyzed for protein C (PC); protein S; antithrombin (AT); activated PC resistance (APCR); lipoprotein (a) [Lp(a)]; lupus anticoagulant; anticardiolipin antibodies; and the methylenetetrahydrofolate reductase C677T (MTHFR), factor V G1619A, factor II G20210A (PT), plasminogen activator inhibitor-1 4G6755G, and tissue factor pathway inhibitor C536T mutations. The frequency of each coagulation abnormality was compared with published international pediatric stroke case and control rates.

RESULTS

At least 1 prothrombotic abnormality was identified in 63% (36 of 57) of children studied, including plasminogen activator inhibitor-1 4G6755G (15 of 56), MTHFR (12 of 56), elevated Lp(a) (12 of 59), APCR (11 of 58), factor V G1619A (5 of 57), PT (3 of 57), PC deficiency (1 of 59), and AT deficiency (1 of 59). The MTHFR mutation, elevated Lp(a), the PT mutation, and AT deficiency rates were similar to rates in cases and more common than control subjects in previously published studies. The rate of children with APCR or multiple abnormalities was higher than in previous pediatric stroke studies. A family history of early thrombosis was identified in one third of the children with a prothrombotic abnormality.

CONCLUSIONS

Two thirds of children in this study had at least 1 of the prothrombotic risk factors tested, and several children had multiple risk factors. These results provide additional evidence that prothrombotic abnormalities are common among children with AIS or porencephaly.

A prospective study of lipoprotein(a) and risk of coronary heart disease among women with type 2 diabetes

AIMS

We examined the association between lipoprotein (Lp)(a) and CHD among women with type 2 diabetes.

METHODS

Of 32,826 women from the Nurses' Health Study who provided blood at baseline, we followed 921 who had a confirmed diagnosis of type 2 diabetes.

RESULTS

During 10 years of follow-up (6,835 person-years), we documented 122 incident cases of CHD. After adjustment for age, smoking, BMI, glycosylated HbA(1)c, triglycerides (TGs), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and other cardiovascular risk factors, the relative risk (RR) comparing extreme quintiles of Lp(a) was 1.95 (95% CI 1.07-3.56). The association was not appreciably altered after further adjustment for apolipoprotein B(100) or several inflammatory biomarkers. Increasing levels of Lp(a) were associated with lower levels of TGs. The probability of developing CHD over 10 years was higher among diabetic women with substantially higher levels of both Lp(a) (>1.07 micromol/l) and TGs (>2.26 mmol/l) than among diabetic women with lower levels (22 vs 10%, p log-rank test=0.049). Diabetic women with a higher level of only Lp(a) or TGs had a similar (14%) risk. In a multivariate model, diabetic women with higher levels of Lp(a) and TGs had an RR of 2.46 (95% CI 1.21-5.01) for developing CHD, as compared with those with lower levels of both biomarkers (p for interaction=0.413). The RRs for women with a higher level of either Lp(a) (RR=1.22, 95% CI 0.77-1.92) or TGs (RR=1.39, 95% CI 0.78-2.42) were comparable.

CONCLUSIONS/INTERPRETATION

Increased levels of Lp(a) were independently associated with risk of CHD among diabetic women.

Components of the Metabolic Syndrome and Risk for First-Ever Acute Ischemic Nonembolic Stroke in Elderly Subjects

Background and Purpose— Metabolic syndrome (MetSyn) represents a constellation of lipid and nonlipid risk factors for cardiovascular disease and is a recognized target for increased behavioral therapy.

Objective— The association between acute ischemic/nonembolic stroke and the MetSyn in elderly individuals was assessed in a population-based case-control study in the prefecture of Ioannina, Greece.

Study Population— A total of 163 patients aged older than 70 years admitted with first-ever-in-a-lifetime acute ischemic/nonembolic stroke and 166 controls were included.

Results— The prevalence of MetSyn (defined according to NCEP/ATP III criteria) was high in stroke patients (46.0% versus 15.7%, P <0.001). Compared with controls as a group (with and without MetSyn), stroke patients with the MetSyn showed higher concentrations of triglycerides, lipoprotein(a), uric acid, and fibrinogen, and lower high-density lipoprotein (HDL) cholesterol and apolipoprotein A-I levels. In logistic regression analysis, crude and adjusted odd ratios (ORs) for MetSyn were 5.33 (95% confidence interval [CI], 2.91 to 9.79; P <0.0001) and 2.59 (95% CI, 1.24 to 5.42; P =0.012), respectively. The analysis of interaction between MetSyn and its individual components revealed significant associations with abdominal obesity (adjusted OR, 2.74; 95% CI, 1.15 to 6.50; P =0.02), hypertension (OR, 2.03; 95% CI, 0.91 to 4.49; P =0.08), high fasting glucose levels (OR, 2.95; 95% CI, 1.19 to 7.35; P =0.02), high triglyceride (OR, 5.55; 95% CI, 2.71 to 11.37; P <0.0001]), and low HDL cholesterol (OR, 5.42; 95% CI, 2.85 to 10.30; P <0.0001). Notably, in stroke patients with the MetSyn the inverse relationship between HDL cholesterol levels and ischemic stroke was negated (OR, 1.04; 95% CI, 1.02 to 1.05; P <0.0001).

Conclusions— MetSyn is associated with an increased risk for acute ischemic/nonembolic stroke in elderly subjects with significant contributions from its individual components. In the presence of MetSyn, HDL cholesterol loses its protective role against ischemic stroke.

Trombophilic screening for nonarteritic anterior ischemic optic neuropathy

BACKGROUND

Nonarteritic anterior ischemic optic neuropathy (NAION) is an ischemic infarction of the optic nerve head, frequently leading to sudden, mostly irreversible loss of vision. In this study blood thrombophilic factors, as well as cardiovascular risk factors were investigated for their relevance to this pathology. Trombophilic risk factors so far not evaluated were included in the study.

PATIENTS AND METHODS

37 NAION patients (4 with sequential second eye involvement) and 81 matched control subjects were examined. From blood, protein C, protein S, antithrombin, von Willebrand antigen levels (vWFAg), and factor V (Leiden) mutation, factor VIIIC level, plasminogen activity, lipoprotein (a) and fibrinogen levels, and presence of anticardiolipin antibodies were investigated. Possibly relevant pathologies [e.g. diabetes mellitus (DM), hypertension, and ischemic heart disease] were also registered.

RESULTS

Elevated Lp(a) and vWFAg levels, DM, F V (Leiden), hypercholesterolemia, and hyperfibinogenemia proved to be significant risk factors associated with NAION. Forward stepwise logistic regression analysis revealed that high Lp(a), DM, and FV (Leiden) were the main predictive components, with odds ratios 16.88 (p=0.012), 5.78 (p=0.022) and 4.44 (p=0.033), respectively.

CONCLUSIONS

Based on our results it appears that thrombophilia is likely to contribute to the development of NAION besides vascular damage due to the presence of cardiovascular risk factors. Further data are needed, however, to justify the suggested use of secondary prophylaxis using anticoagulant/antiplatelet therapy.