Lipids and stroke: a paradox resolved

The onset of cerebral infarction may be affected by differences in atmospheric pressure distribution patterns

Background

Some papers have highlighted a possible causal relationship between the onset of ischemic stroke and weather conditions. This study aimed to elucidate the onset mechanism of cerebral infarction from a meteorological approach. We focused on the atmospheric pressure distribution patterns (APDPs).

Methods

The subjects are 221 cases diagnosed as cardiogenic cerebral embolism (Group A) and 612 cases diagnosed as atherosclerotic cerebral thrombosis (Group B). We investigated the APDP on the date closest to the date and time of onset of cerebral infarction in each patient on the website and chose the most similar one from the reported 11 APDPs. Groups A and B were compared for clinical characteristics and the appearance rate of each APDP in each group.

Results

The clinical characteristics of Groups A and B were consistent with some previously reported clinical characteristics of cerebral embolism and cerebral thrombosis except for smoking. The appearance rate of the other high-pressure type, which cannot be classified as either the anticyclone belt type or the migratory anticyclone type, in Group B was statistically significantly higher than that in Group A, and the appearance rate of the anticyclone belt type in Group A was statistically significantly higher than that in Group B (p < 0.05, Fisher's exact probability method, respectively).

Conclusions

Cerebral embolism and cerebral thrombosis exhibited significant differences in APDPs on the day of onset. Dehydration particularly in the other high-pressure type or in the anticyclone belt type should be prevented. Further investigation should focus on the other meteorological factors.

Machine Learning-Based Model for Prediction of Hemorrhage Transformation in Acute Ischemic Stroke After Alteplase

Hemorrhage transformation (HT) is the most dreaded complication of intravenous thrombolysis (IVT) in acute ischemic stroke (AIS). The prediction of HT after IVT is important in the treatment decision-making for AIS. We designed and compared different machine learning methods, capable of predicting HT in AIS after IVT. A total of 345 AIS patients who received intravenous alteplase between January 2016 and June 2021 were enrolled in this retrospective study. The demographic characteristics, clinical condition, biochemical data, and neuroimaging variables were included for analysis. HT was confirmed by head computed tomography (CT) or magnetic resonance imaging (MRI) within 48 h after IVT. Based on the neuroimaging results, all of the patients were divided into the non-HT group and the HT group. Then, the variables were applied in logistic regression (LR) and random forest (RF) algorithms to establish HT prediction models. To evaluate the accuracy of the machine learning models, the models were compared to several of the common scales used in clinics, including the multicenter stroke survey (MSS) score, safe implementation of treatments in stroke (SITS) score, and SEDAN score. The performance of these prediction models was evaluated using the receiver operating characteristic (ROC) curve (AUC). Forty-five patients had HT (13.0%) within 48 h after IVT. The ROC curve results showed that the AUCs of HT that were predicted by the RF model, LR model, MSS, SITS, and SEDAN scales after IVT were 0.795 (95% CI, 0.647–0.944), 0.703 (95% CI, 0.515–0.892), 0.657 (95% CI, 0.574–0.741), 0.660 (95% CI, 0.580–0.740) and 0.655 (95% CI, 0.571–0.739), respectively. The RF model performed better than the other models and scales. The top four most influential factors in the RF importance matrix plot were triglyceride, Lpa, the baseline NIHSS, and hemoglobin. The SHapley Additive exPlanation values made the RF prediction model clinically interpretable. In this study, an RF machine learning method was successfully established to predict HT in AIS patients after intravenous alteplase, which the sensitivity was 66.7%, and the specificity was 80.7%.

Apolipoprotein E ε4 Polymorphism as a Risk Factor for Ischemic Stroke: A Systematic Review and Meta-Analysis

Introduction

Rising studies indicate that the apolipoprotein E (APOE) gene is related to the susceptibility of ischemic stroke (IS). However, certain consensus is limited by the lack of a large sample size of researches. This meta-analysis was performed to explore the potential association between the APOE gene and IS.

Methods

To identify relevant case control studies in English publications by October 2020, we searched PubMed, Embase, Web of Science, and the Cochrane Library. Pooled odds ratios (ORs) with fixed- or random-effect models and corresponding 95% confidence intervals (CIs) were calculated to analyze potential associations.

Results

A total of 55 researches from 32 countries containing 12207 IS cases and 27742 controls were included. The association between APOE gene ε4 mutation and IS was confirmed (ε4 vs. ε3 allele: pooled OR = 1.374, 95% CI, 1.214-1.556; ε2/ε4 vs. ε3/ε3: pooled OR = 1.233, 95% CI, 1.056-1.440; ε3/ε4 vs. ε3/ε3: pooled OR = 1.340, 95% CI, 1.165-1.542; ε4/ε4 vs. ε3/ε3: pooled OR = 1.833, 95% CI, 1.542-2.179; and APOE ε4 carriers vs. non-ε4 carriers: pooled OR = 1.377; 95% CI, 1.203-1.576). Interestingly, APOE ε4 mutation showed a dose-response correlation with IS risk (ε4/ε4 vs. ε2/ε4: pooled OR = 1.625; 95% CI, 1.281-2.060; ε4/ε4 vs. ε3/ε4: pooled OR = 1.301; 95% CI, 1.077-1.571). Similar conclusions were drawn in the small artery disease (SAD) subtype, but not in large artery atherosclerosis (LAA) or in cardioaortic embolism (CE), by subgroup analysis.

Conclusions

These observations reveal that specific APOE ε4 mutation was significantly associated with the risk of IS in a dose-dependent manner, while APOE ε4 mutation was related to SAD subtype onset without a cumulative effect.

Simultaneously targeting SOAT1 and CPT1A ameliorates hepatocellular carcinoma by disrupting lipid homeostasis

Lipid homeostasis plays a fundamental role in the development of hepatocellular carcinoma (HCC). However, the mechanisms that regulate lipid homeostasis to avoid lipotoxicity in HCC remain elusive. Here, we found high-fat diet (HFD) improved the expression of sterol o-acyltransferase1 (SOAT1) and carnitine palmitoyltransferase 1A (CPT1A) in diethylnitrosamine-induced HCC. Bioinformatic analysis showed that SOAT1-mediated fatty acid storage and CPT1A-mediated fatty acids oxidation (FAO) formed a double-negative feedback loop in HCC. We verified that SOAT1 inhibition enhanced CPT1A protein, which shuttled the released fatty acids into the mitochondria for oxidation in vivo and in vitro. Besides, we further confirmed that CPT1A inhibition converted excess fatty acids into lipid drops by SOAT1 in vitro. Simultaneously targeting SOAT1 and CPT1A by the small-molecule inhibitors avasimibe and etomoxir had synergistic anticancer efficacy in HCC in vitro and in vivo. Our study provides new mechanistic insights into the regulation of lipid homeostasis and suggests the combination of avasimibe and etomoxir is a novel strategy for HCC treatment.

Frequency and Characteristics of Metabolic Syndrome in Patients With Ischemic Stroke Admitted to a Tertiary Care Hospital in Karachi

Introduction

Metabolic syndrome (MetS) is defined as a syndrome of truncal obesity, insulin resistance, hypertension, hypertriglyceridemia, and dyslipidemia. It is well known that MetS increases the risk of cardiovascular disease and adverse events. Each of its components is associated with an increased risk of cardiovascular disease, but data on the association with ischemic stroke are scarce. At the international level, a significant body of research has been conducted on this issue, but the situation is very different in Pakistan. Very little data are present on the subject matter. This study is an endeavor in this direction, generating data, that can be used in early identification and developing treatment services for patients with ischemic stroke having MetS.

Aims

To determine the frequency of MetS in ischemic stroke patients admitted to a tertiary care hospital in Karachi, Pakistan.

Methods

This six-month observational and cross-sectional study was conducted at Medical Unit I, Jinnah Postgraduate Medical Centre from July 1, 2019, to December 31, 2019. Patients with a diagnosis of acute ischemic stroke were enrolled. Detailed history, physical examination, and biochemical measurements were noted. The presence of MetS was defined in accordance with the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III)/American Heart Association (AHA) guidelines.

Results

A total of 224 patients fulfilling the inclusion criteria were inducted into this study. The mean age of presentation was 61.04 ± 14.72 years, and more than two-thirds of the patients were ≥60 years of age. A total of 150 (66.96%) patients with ischemic stroke also had MetS. The male-to-female ratio in this group was 2:1. The most common variables constituting the MetS were truncal obesity, hypertension, and dyslipidemia. The median MetS score was 3.

Conclusions

MetS is highly prevalent in patients presenting with ischemic stroke irrespective of age or gender. The three most deranged and common components of MetS in these patients are truncal obesity, hypertension, and dyslipidemia.

Lipids and Lipid Mediators Associated with the Risk and Pathology of Ischemic Stroke

Stroke is a severe neurological disorder in humans that results from an interruption of the blood supply to the brain. Worldwide, stoke affects over 100 million people each year and is the second largest contributor to disability. Dyslipidemia is a modifiable risk factor for stroke that is associated with an increased risk of the disease. Traditional and non-traditional lipid measures are proposed as biomarkers for the better detection of subclinical disease. In the central nervous system, lipids and lipid mediators are essential to sustain the normal brain tissue structure and function. Pathways leading to post-stroke brain deterioration include the metabolism of polyunsaturated fatty acids. A variety of lipid mediators are generated from fatty acids and these molecules may have either neuroprotective or neurodegenerative effects on the post-stroke brain tissue; therefore, they largely contribute to the outcome and recovery from stroke. In this review, we provide an overview of serum lipids associated with the risk of ischemic stroke. We also discuss the role of lipid mediators, with particular emphasis on eicosanoids, in the pathology of ischemic stroke. Finally, we summarize the latest research on potential targets in lipid metabolic pathways for ischemic stroke treatment and on the development of new stroke risk biomarkers for use in clinical practice.

Risk Factors, Clinical Features and Prognosis for Subtypes of Ischemic Stroke in a Chinese Population

It is unanimously accepted that stroke is a highly heterogeneous disorder. Different subtypes of ischemic stroke may have different risk factors, clinical features, and prognoses. The aim of this study was to evaluate the risk factors, clinical characteristics, and prognoses of different subtypes of ischemic stroke defined by the Trial of ORG10172 in Acute Stroke Treatment (TOAST) criteria. We prospectively analyzed the data from 530 consecutive patients who were admitted to our hospital with acute ischemic stroke within 7 days of stroke onset during the study period. Standardized data assessment was used and the cause of ischemic stroke was classified according to the TOAST criteria. Patients were followed up till 30 and 90 days after stroke onset. It was found that large-artery atherosclerosis was the most frequent etiology of stroke (37.4%), and showed the highest male preponderance, the highest prevalence of previous transient ischemic attack, and the longest hospital stay among all subtypes. Small artery disease (36.4%) was associated with higher body mass index, higher plasma triglycerides, and lower plasma high-density lipoprotein cholesterol than cardioembolism. Cardioembolism (7.7%), which was particularly common in the elderly (i.e., individuals aged 65 years and older), showed the highest female preponderance, the highest prevalence of atrial fibrillation, the earliest presentation to hospital after stroke onset, the most severe symptoms on admission, the maximum complications associated with an adverse outcome, and the highest rate of stroke recurrence and mortality. Our results suggest that ischemic stroke should be regarded as a highly heterogeneous disorder. Studies involving risk factors, clinical features, and prognoses of ischemic stroke should differentiate between etiologic stroke subtypes.

Metabolic syndrome and its components with neuron-specific enolase: a cross-sectional study in large health check-up population in China

OBJECTIVE

This study was aimed at investigating the relationship between neuron-specific enolase (NSE) and components of metabolic syndrome (MS).

DESIGN

Cross-sectional study.

SETTING

Chinese health check-up population.

PARTICIPANTS

40 684 health check-up people were enrolled in this study from year 2014 to 2016.

MAIN OUTCOME MEASURES

OR and coefficient for MS.

RESULTS

The percentage of abnormal NSE and MS was 26.85% and 8.85%, respectively. There were significant differences in sex, body mass index, drinking habit, triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), blood pressure and MS between low-NSE and high-NSE groups. In logistic regression analysis, elevated NSE was present in MS, higher body mass index, hypertriglyceridaemia, hypertension and low-HDL groups. Stepwise linear analysis showed a negative correlation between NSE and fasting blood glucose (FBG) (<6.0 mmol/L), and a positive correlation between NSE and TGs (<20 mmol/L), systolic blood pressure (75-200 mm Hg), HDL-C (0.75-2.50 mmol/L), diastolic blood pressure (<70 mm Hg) and FBG (6.00-20.00 mmol/L). Furthermore, MS was positively correlated with NSE within the range of 2.00-7.50 ng/mL, but had a negative correlation with NSE within the range of 7.50-23.00 ng/mL.

CONCLUSION

There are associations between NSE with MS and its components. The result suggests that NSE may be a potential predictor of MS. Further research could be conducted in discussing the potential mechanism involved.

Pre- and Post-operative Comparative Analysis of Serum Lipid Profile in Patients with Cholelithiasis

BACKGROUND

Gallstones have become a major health problem because of their silent manifestation and unclear pathogenesis. Although the association between the disturbed lipid metabolism and formation of gallstones has been elucidated in many studies, the effect of cholecystectomy on lipid profile has not been studied in detail.

AIM

The aim of the present study was to study the effect of cholecystectomy on lipid levels in patients with gallstones.

MATERIALS AND METHODS

The study was conducted on 50 patients with gallstones and 30 healthy volunteers for comparison of lipid levels. Subsequently, cholecystectomy was conducted on patients with gallstones and pre- and post-operative lipid levels were compared.

RESULTS

There was a significant decrease in total cholesterol, and triglycerides levels and increase in high-density lipoprotein levels after 1 month of surgery, while low-density lipoprotein levels and very low-density lipoprotein were not statistically changed.

CONCLUSION

Cholecystectomy can significantly improve lipid levels in patients with gallstones.

Risk factors and subtypes of acute ischemic stroke. A study at King Fahd Hospital of the University

Objective:

To identify the different subtypes of acute ischemic stroke, and estimate the frequency of various risk factors among these patients.

Methods:

In this retrospective, cross-sectional study, we reviewed the medical records of patients admitted with the diagnosis of acute ischemic stroke at King Fahd Hospital of the University, Al-Khobar, Saudi Arabia from March 2008 till December 2015. The demographic characteristics, subtypes of stroke, risk factors (hypertension, diabetes mellitus, hyperlipidemia, coronary artery disease, atrial fibrillation, valvular heart disease) and other relevant data were documented on pre-defined data sheets.

Results:

The records of 343 patients were included in the study; 64.4% were male and 35.6% were female. The mean age was 59.3+13.6 (mean+SD) years for males, and 66.8+14.9 years for females. Small vessel occlusion was the most common etiologic subtype of ischemic stroke (32.1%), followed by cardio embolic (21.9%), and large artery atherosclerosis (14.6%). The middle cerebral artery was the most commonly affected territory. Hypertension was found in 78.1%, diabetes mellitus in 62.7%, hyperlipidemia in 54.8%, and ischemic heart disease in 24.2% of patients.

Conclusion:

Small vessel occlusion was the most common etiology in our cohort. The onset of stroke at a relatively younger age group in the male population is of great concern and needs to be verified by further epidemiological studies. Adequate control of modifiable risk factors may help in reducing the disease burden caused by stroke.

Risk-factor profile for the incidence of subarachnoid and intracerebral haemorrhage, cerebral infarction, and unspecified stroke during 21 years' follow-up in men

Aims: To study the risk-factor profile for the incidence of non-fatal and fatal stroke among middle-aged men according to the stroke subtypes subarachnoid or intracerebral haemorrhage, cerebral infarction, and unspecified stroke. Methods: The study design is a prospective cohort study. A total of 16,209 men aged 40—49 years resident in Oslo were screened for cardiovascular disease risk factors in 1972—73. Of these, 14,403 men had no cardiovascular symptoms or diseases or diabetes. The incidence of stroke after 21 years of follow-up of all men was extracted from hospital records and linkage to Statistics Norway. Results: A total of 429 non-fatal and 107 fatal stroke events were registered. Case fatality within 28 days (number and percentage of cases) was 51% (41, 7.7%) for subarachnoid haemorrhage, 39% (67, 12.6%) for cerebral haemorrhage, 10% (246, 46.3%) for cerebral infarct, and 19% (177, 33.4%) for unspecified stroke. Risk of stroke (not subarachnoid haemorrhage) increased with the presence of symptoms or a history of cardiovascular disease or diabetes. In multivariate analysis of men without CVD or diabetes, high blood pressure was a risk factor for all subtypes of stroke; furthermore, daily smoking was a risk factor for all subtypes except subarachnoid haemorrhage. Serum cholesterol and glucose concentrations and height (inverse association) were independently associated with cerebral infarction. Smoking was a significantly stronger predictor of fatal than non-fatal events. Conclusions: The risk-factor profile differed according to the underlying subtype of stroke. Cerebral infarction clearly shared with myocardial infarction the classical risk factors, including non-fasting glucose concentration.

Apolipoprotein E and First-ever Ischaemic Stroke in Greek Hospitalized Patients

The association between apolipoprotein E (ApoE) polymorphism and stroke is still controversial. This study investigated the potential association between ApoE genotypes and stroke subtypes, and risk factors for ischaemic stroke in Greek patients hospitalized with their first-ever ischaemic stroke. One hundred patients (70 men and 30 women; mean age ± SD 60.7 ± 9.8 years) were included in the study. The control group comprised 96 age-and sex-matched healthy volunteers. Cerebral infarction was classified as atherothrombotic, cardio-embolic or lacunar small-vessel stroke. The three common ApoE alleles (E2, E3 and E4) were determined using the seminested polymerase chain reaction. No significant difference in the ApoE alleles was found between patients and controls. Similarly, there was no significant association between ApoE alleles and stroke subtypes, common risk factors for ischaemic stroke and neck vessel stenosis. Although the sample size was small, these results do not support a role for ApoE polymorphism in the pathogenesis of ischaemic stroke.

Comparison of Risk Factor between Lacunar Stroke and Large Artery Atherosclerosis Stroke: A Cross-Sectional Study in China

Background

Stroke is the second most common cause of mortality in China. Although most subtypes of ischemic stroke share similar risk factors, they have different etiologies. Our study aimed to evaluate the different risk factor profiles between the stroke subtypes, lacunar infarcts (LI) and large-artery atherosclerosis (LAA), and clarify the characteristics of current acute ischemic stroke in China.

Methods

In this cross-sectional study, we analyzed the clinical characteristics of 1982 patients with acute ischemic stroke who were admitted to the neurology department at the Peking University First Hospital between 2007 and 2014. Ischemic stroke was further classified into LAA, LI, cardioembolism (CE) and undetermined causes of infarction (UDI) according to TOAST classification. Demographic characteristics, risk factors, as well as the findings of laboratory and imaging tests of 1773 patients with LAA and LI, were analyzed by univariate and multivariate logistic analysis.

Results

Of the 1982 ischemic stroke patients included in this study, 1207 were diagnosed with LAA, 566 with LI, 173 with cardioembolism (CE) and 36 with undetermined causes of infarction (UDI). By comparing the risk factors in multivariate logistic regression analysis, hypertension [odds ratio (OR) = 1.832] and white matter leukoaraiosis (WML) (OR = 1.865) were found to be more strongly correlated with LI than LAA. Low density lipoprotein- cholesterol (LDL-c) (OR = 0.774) were more strongly related to LAA than LI.

Conclusions

This study found that hypertension and WML were more strongly correlated with LI than LAA. LDL-c was more strongly related to LAA than LI.

Identification of Rbd2 as a candidate protease for sterol regulatory element binding protein (SREBP) cleavage in fission yeast

Lipid homeostasis in mammalian cells is regulated by sterol regulatory element-binding protein (SREBP) transcription factors that are activated through sequential cleavage by Golgi Site-1 and Site-2 proteases. Fission yeast SREBP, Sre1, engages a different mechanism involving the Golgi Dsc E3 ligase complex, but it is not clearly understood exactly how Sre1 is proteolytically cleaved and activated. In this study, we screened the Schizosaccharomyces pombe non-essential haploid deletion collection to identify missing components of the Sre1 cleavage machinery. Our screen identified an additional component of the SREBP pathway required for Sre1 proteolysis named rhomboid protein 2 (Rbd2). We show that an rbd2 deletion mutant fails to grow under hypoxic and hypoxia-mimetic conditions due to lack of Sre1 activity and that this growth phenotype is rescued by Sre1N, a cleaved active form of Sre1. We found that the growth inhibition phenotype under low oxygen conditions is specific to the strain with deletion of rbd2, not any other fission yeast rhomboid-encoding genes. Our study also identified conserved residues of Rbd2 that are required for Sre1 proteolytic cleavage. All together, our results suggest that Rbd2 is a functional SREBP protease with conserved residues required for Sre1 cleavage and provide an important piece of the puzzle to understand the mechanisms for Sre1 activation and the regulation of various biological and pathological processes involving SREBPs.

Statins decrease the risk of stroke in individuals with heterozygous familial hypercholesterolemia: A systematic review and meta-analysis

BACKGROUND

Familial hypercholesterolemia (FH) is undoubtedly associated with premature coronary heart disease, but it is debatable whether FH increases the risk for stroke.

OBJECTIVE

To meta-analyze available evidence regarding the incidence of stroke in individuals with heterozygous (He) FH.

METHODS

We conducted a systematic review and a meta-analysis of epidemiological studies, including English-language publications until June 2015; four observational studies, with 3374 participants with HeFH, were included in the analysis. Cerebrovascular disease comprised of ischemic stroke or transient ischemic attack. Since studies did not include any control subjects, the corresponding general population of the same reference area and period of time for each HeFH study served as control group. Analyses were performed according to the period of time during which the studies were conducted: prestatin and statin era (before and after 1987 when lovastatin was launched).

RESULTS

In the prestatin era, individuals with HeFH exhibited a higher risk for stroke compared with the general population [odds ratio (OR) = 7.658, 95% confidence interval (CI): 6.059-9.678, p < 0.01]. In contrast, FH subjects had a lower odds for stroke following the generalization of statin therapy (OR = 0.251, 95% CI: 0.176-0.358, p < 0.01).

CONCLUSIONS

Taking into account the small number of studies and methodological issues, HeFH was associated with a higher risk of cerebrovascular disease compared with the general population in the prestatin era, which was significantly reduced after the introduction of statin therapy.

ACE-II genotype and I allele predicts ischemic stroke among males in south India

Two hundred ischemic stroke patients and 193 age and sex matched healthy controls were studied for the presence of Angiotensin Converting Enzyme Insertion/Deletion (ACE I/D) gene polymorphism. The PCR studies revealed that ACE 'II' (OR = 2.055; p = 0.004) genotype and 'I' (OR = 1.411; p = 0.018) alleles were significantly associated with IS patients. Gender specific analysis revealed a strong association of 'II' (OR = 2.044; p = 0.014) genotype and 'I' (OR = 1.531; p = 0.011) allele with male sex. Classification of patients based on TOAST criteria, revealed a significant association for 'II' genotype (OR = 1.713; p = 0.043) and 'I' (OR = 1.382; p = 0.039) allele in LVD patients only. When the data was stratified based on age and sex, a statistically significant association was observed for ACE 'II' genotype (OR = 2.288; p = 0.006) and 'I' allele (OR = 1.395; p = 0.054) in IS male patients of > 50 years of age. The ACE 'D' allele was found to be increased in controls (OR = 0.709; p = 0.018) than IS patients. Multivariate logistic regression analysis showed that smoking and diabetes were the most powerful independent risk factor in LVD type of stroke. Thus, we presented here an evidence for a strong association of ACE 'II' genotype and 'I' allele compounded by factors such as smoking and diabetes among south Indian IS patients.

Sterol regulatory element-binding protein (SREBP) cleavage regulates Golgi-to-endoplasmic reticulum recycling of SREBP cleavage-activating protein (SCAP)

Sterol regulatory element-binding protein (SREBP) transcription factors are central regulators of cellular lipogenesis. Release of membrane-bound SREBP requires SREBP cleavage-activating protein (SCAP) to escort SREBP from the endoplasmic reticulum (ER) to the Golgi for cleavage by site-1 and site-2 proteases. SCAP then recycles to the ER for additional rounds of SREBP binding and transport. Mechanisms regulating ER-to-Golgi transport of SCAP-SREBP are understood in molecular detail, but little is known about SCAP recycling. Here, we have demonstrated that SCAP Golgi-to-ER transport requires cleavage of SREBP at site-1. Reductions in SREBP cleavage lead to SCAP degradation in lysosomes, providing additional negative feedback control to the SREBP pathway. Current models suggest that SREBP plays a passive role prior to cleavage. However, we show that SREBP actively prevents premature recycling of SCAP-SREBP until initiation of SREBP cleavage. SREBP regulates SCAP in human cells and yeast, indicating that this is an ancient regulatory mechanism.

Stroke prevention with lipid-lowering therapy

Despite great progress in the medical sciences, the effects of stroke in the modern world are profound, both in the aspect of death and disability it causes, as well as the economic demands it poses. The most important modifiable risk factors of stroke are arterial hypertension, heart disease, cigarette smoking and transient ischemic attacks. Secondary risk factors include hyperlipidemia, obesity and physical inactivity. The role of lipids in atherosclerosis and cerebral vascular events, and the influence of lipid-lowering therapies on stroke occurrence is a subject of debate in the medical literature. The aim of this review is to answer the basic question of whether lipid-lowering therapy should be used routinely in stroke prevention.

Prevalence of metabolic syndrome in stroke patients: a prospective multicenter study in Japan

AIMS

The fact that Metabolic Syndrome (MetS) increases the risk of atherosclerosis has been epidemiologically studied and proven; however, a prospective study on the prevalence of MetS in stroke patients has never been conducted because of the difficulty in diagnosis under critical illness in the acute phase. Therefore, we conducted a prospective multicenter study to investigate the prevalence of MetS in stroke patients with modified diagnostic criteria for MetS.

METHODS

Stroke patients admitted in the seven participating Emergency and Critical Care Centers within the two years from April 2007 were registered in this study as a prospective multicenter study. Inclusion criteria were 50 to 89 year-old stroke patients who presented within three days from the onset of symptoms. A total of 992 subjects were classified according to the stroke type and the prevalence of MetS and the associated risk factors were investigated. The participants in a medical checkup without any history of a stroke were enrolled as the control group, and compared between the two groups.

RESULTS

The prevalence of MetS as well as hyperglycemia and dyslipidemia in the infarction group was significantly higher than that in the non-stroke group. While the hemorrhage group showed no significant difference in the prevalence of MetS, only hypertension was significantly high. According to a subtype analysis, there is a significant correlation between waist circumference increment of the stroke patients and the prevalence of the risk factors of hypertension, hyperglycemia and dyslipidemia.

CONCLUSIONS

Different risk factors are significantly related to the type of stroke.

Lipoprotein(a), ferritin, and albumin in acute phase reaction predicts severity and mortality of acute ischemic stroke in North Indian Patients

BACKGROUND

Inflammation plays a crucial role in the pathogenesis and prognosis of stroke. We studied the behavior of lipoprotein(a) [Lp(a)], ferritin, and albumin as acute phase reactants and their roles in the severity and mortality of stroke.

METHODS

We recruited 100 consecutive patients with acute ischemic stroke and 120 controls. Blood samples were drawn on days 1 and 7 and at both 3 and 6 months. Stroke was classified using Trial of Org 10172 in Acute Stroke Treatment classification. Stroke severity was assessed using the National Institutes of Health Stroke Scale. Prognosis at 6 months was assessed using the modified Rankin Scale, and mortality was assessed using the Kaplan-Meier analysis. Serum levels of interleukin-6 (IL-6), Lp(a), ferritin, and albumin were measured using enzyme-linked immunosorbent assay, immunoturbidimetry, and chemiluminescence commercial kits, respectively.

RESULTS

Levels of IL-6, Lp(a), and ferritin were consistently higher among cases than controls (P < .0001). Serum Lp(a) levels peaked at day 7 after stroke and tapered thereafter. Albumin levels were lower than controls on admission day and increased subsequently. In our study, Lp(a) acted as an acute phase reactant while albumin acted as a negative acute phase reactant. There was no association between Trial of Org 10172 in Acute Stroke Treatment subtype and elevated serum levels of Lp(a), albumin, and ferritin. Lp(a) and ferritin were high in patients with severe stroke. Albumin was negatively correlated with stroke severity. Serum levels of Lp(a) ≥ 77 mg/dL, albumin ≤ 3.5 g/dL, and ferritin ≥ 370 ng/dL is associated with a significantly increased risk of having a poorer outcome in stroke. Serum levels of Lp(a) >77 mg/dL and albumin <3.5 g/dL were also associated with increased mortality.

CONCLUSIONS

High levels of Lp(a) and ferritin and low levels of albumin are associated with increased severity and poorer long term prognosis of stroke. Patients with admission levels of Lp(a) >77 mg/dL and albumin <3.5 g/dL had increased mortality.

Changes in lipids and lipoprotein indices in relation to the severity of hypertension in newly diagnosed hypertensive nigerians

Hypertension and dyslipidaemia are important components of metabolic syndrome and both are known to complicate each other. Materials and Methods. A total of 149 subjects consisting of 107 hypertensive patients, grouped into 3 (of 37, 35, and 35 patients categorized based on the grade of hypertension as grade 1, grade 2, and grade 3, resp.) and 42 controls, were recruited for this study. Each subject had a recording of the bio- and anthropometric data comprising of the age, height, weight, body mass index (BMI), and abdominal circumference (AC). The blood pressure was also recorded. Fasting blood was collected and serum was used for the estimation of the lipids: total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG), while low density lipoprotein cholesterol (LDL-C) and VLDL were estimated using Friedewald formula. Findings. Patients with hypertension had higher lipid and lipoprotein levels than the controls and the values became more significant with increasing severity of hypertension. The difference was statistically significant for TC, LDL-C, and VLDL-C (P < 0.05). Conclusion. This study showed that lipid and lipoprotein cholesterol abnormalities exist and even worsen with severity of hypertension. It is important that investigations in patients with hypertension should include a lipid profile.

[Advances in the prevention, diagnosis and therapy of vascular diseases]

Atherosclerosis is a systemic disease affecting the coronary, carotid, intracerebral, renal and peripherial arteries. The early morphological and functional impairments could be detected in the second or third decades of life and their progression depend on the number and severity of risk factors and individual susceptility. Although the vascular risk factors (smoking, overweight, age, unhealthy diet, lack of physical exercise, hypertension, diabetes mellitus, chronic kidney disease and dyslipidemia) are the same and common in the different vascular diseases, the present clinical routine artificially classifies the diagnosis and therapy of different vascular diseases into different subfields of medicine with the negative impact of possible polypragmasia. Recently, worldwide health surveys (e.g. REACH registry) have proven the usefulness of a holistic approach in the diagnosis and therapy of multiorgan-affected vascular patients. This review summarizes the multidisciplinary advances and future perspective of vascular diseases.

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.

Association of apolipoprotein A5 gene promoter region -1131T>C with risk of stroke in Han Chinese

BACKGROUND

Ischemic stroke is a suddenly developing temporary or often permanent damage of the brain. Several candidate genes have been shown to have an impact in the pathogenesis of ischemic stroke. Recently, the -1131T>C polymorphism in apolipoprotein A5 (APOA5) gene has been reported to be associated with ischemic stroke in different racial groups, but no data is available currently in Han Chinese. Our study is to investigate the association between the APOA5 gene polymorphism -1131T>C and the susceptibility to ischemic stroke in Han Chinese.

METHODS

310 controls and 342 patients with classified ischemic stroke were performed to detect the -1131T>C alleles genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis in independent case-control study.

RESULTS

TG levels of subjects carrying -1131C allele were elevated compared to the subjects with -1131T allele in all ischemic stroke subgroups and in controls. The serum TC, LDL-C and HDL-C levels did not differ between subjects with T or C alleles in each group. The overall distribution of APOA5 -1131T>C genotype among stroke patients and controls was significantly different (P<0.01). Frequencies of CC homozygote and C allele were significantly higher in all stroke subgroups than those in control group. After adjustment for conventional risk factors, logistic regression analysis showed that C allele carrier (CC+CT) of -1131T>C was an independent risk factor for all stroke subgroups (P<0.05).

CONCLUSIONS

APOA5 gene -1131T>C polymorphism is independently associated with the development of ischemic stroke in Chinese Han population, and CC homozygote may have a promoting effect on ischemic stroke.

Triglyceride level modifying functional variants of GALTN2 and MLXIPL in patients with ischaemic stroke

BACKGROUND

Recent genome-wide studies identified several genetic variants associated with blood lipid level alterations. Because affected lipid metabolism can confer risk to the development of ischaemic stroke, we studied three polymorphisms reportedly associated with triglyceride-level changes, rs17145738 and rs3812316 of the MLXIPL locus, and rs4846914 variant of GALNT2 gene in biobanked samples of patients with stroke. This pool of samples was previously investigated for haplotype tagging minor alleles of apolipoprotein A5 gene (T-1131C, T1259C, IVS3+G476A and C56G), and an association was found between the minor allele carriage and the triglyceride levels, and also these variants were found to confer risk to the development of stroke.

METHODS

Here, a total of 467 patients with stroke, stratified as large vessel, small vessel and mixed stroke groups, and 156 control subjects were genotyped using PCR-RFLP methods.

RESULTS

In the current study, we could not verify association of the variants analyzed either with triglyceride and total cholesterol levels or with the risk of ischaemic stroke susceptibility.

CONCLUSIONS

The data presented here revealed differentiated risk nature of the triglyceride level modifying natural gene variants.

Pharmacologic inhibition of squalene synthase and other downstream enzymes of the cholesterol synthesis pathway: a new therapeutic approach to treatment of hypercholesterolemia

Hypercholesterolemia is a major risk factor for the development of atherosclerotic vascular diseases. The most popular agents for cholesterol reduction are the statin drugs, which are competitive inhibitors of hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase, the primary rate-limiting enzyme in the hepatic biosynthesis of cholesterol. Although relatively safe and effective, the available statins can cause elevations in liver enzymes and myopathy. Squalene synthase is another enzyme that is downstream to HMG-CoA reductase in the cholesterol synthesis pathway and modulates the first committed step of hepatic cholesterol biosynthesis at the final branch point of the cholesterol biosynthetic pathway. Squalene epoxidase and oxidosqualene cyclase are other enzymes that act distally to squalene synthase. Pharmacologic inhibitors of these downstream enzymes have been developed, which may reduce low-density lipoprotein cholesterol and reduce the myopathy side effect seen with upstream inhibition of HMG-CoA. At this juncture, one squalene synthase inhibitor, lapaquistat (TAK-475) is in active clinical trials as a monotherapy, but there have been suggestions of increased hepatotoxicity with the drug.

Targeting eNOS and beyond: emerging heterogeneity of the role of endothelial Rho proteins in stroke protection

Currently available modalities for the treatment of acute ischemic stroke are aimed at preserving or augmenting cerebral blood flow. Experimental evidence suggests that statins, which show 25-30% reduction of stroke incidence in clinical trials, confer stroke protection by upregulation of eNOS and increasing cerebral blood flow. The upregulation of eNOS by statins is mediated by inhibition of small GTP-binding protein RhoA. Our recent study uncovered a unique role for a Rho-family member Rac1 in stroke protection. Rac1 in endothelium does not affect cerebral blood flow. Instead, inhibition of endothelial Rac1 leads to broad upregulation of the genes relevant to neurovascular protection. Intriguingly, inhibition of endothelial Rac1 enhances neuronal cell survival through endothelium-derived neurotrophic factors, including artemin. This review discusses the emerging therapeutic opportunities to target neurovascular signaling beyond the BBB, with special emphasis on the novel role of endothelial Rac1 in stroke protection.

Functional variants of glucokinase regulatory protein and apolipoprotein A5 genes in ischemic stroke

Both the natural variants of the apolipoprotein A5 (APOA5) and the glucokinase regulatory protein gene (GCKR) have been shown to associate with increased fasting triglyceride levels. Here, we investigated the possible association of the functional variants of these two genes with non-fasting triglyceride levels and their susceptibility nature in ischemic stroke. A total of 513 stroke patients and 172 healthy controls were genotyped. All the APOA5 variants (T-1131C, IVS3 + G476A, C56G, and T1259C) were associated with increased triglyceride levels in all stroke patients and controls; except for T1259C, they all conferred risk for the disease. No such association was found for the examined GCKR rs1260326 (C1337T) variant. Furthermore, we examined the effects of specific combinations of the GCKR rs1260326 and APOA5 polymorphisms. Our findings confirmed the previous results regarding the association of APOA5 variants with triglyceride-level increase and stroke susceptibility of these alleles. By contrast, we could not detect any association of the studied GCKR allele with triglyceride levels or with the susceptibility of stroke in the same cohort of patients. In addition, the effect of APOA5 did not change significantly when specific combinations of the two genes were present.

Cholecystectomy or Cholelithiasis - a Missed Marker for Hyperlipidaemia? A Combined Retrospective and Prospective Study

Background

Multiple studies have shown an association between gallstones and abnormal lipids and the latter increases the risk of coronary artery disease and stroke. Our study investigates the current incidence of lipid abnormalities in patients who have undergone cholecystectomy (retrospective study) and who have gallstones (prospective study).

Methods

We conducted a retrospective analysis of the lipid profiles of 715 patients who underwent cholecystectomy in a rural district general hospital from 2003 to 2006. Details of the cholecystectomy patients were obtained from Patient Information and Management System (PIMS) and cross-referenced with biochemical and histological databases. Following this a prospective study was undertaken of 129 patients presenting with gallstones.

Results

Of the 715 patients, three quarters were women. Only 36.2% of women and 36.9% of men who had a cholecystectomy had a full lipid profile including high density lipoproteins (HDL) and low density lipoproteins (LDL). Of these, 76.4% of women and 70.7% of men had an abnormal lipid profile. In the prospective group, 91.1 % of women and 96.3 % of men had a full lipid profile. These were abnormal in 81.4% of women and 70.4 % of men. Hypercholesterolemia and raised LDL were the most common abnormalities in both sexes. Hypertriglyceridaemia was common in both sexes in both the groups.

Conclusions

Patients who have had a cholecystectomy or gallstones should have a full fasting lipid profile, including HDL and LDL, as a large proportion will be abnormal. Current guidelines suggest they are at an increased risk of cardiovascular disease and should be treated.

Interaction of angiotensin-converting enzyme and apolipoprotein E gene polymorphisms in ischemic stroke involving large-vessel disease

A relationship between apolipoprotein E (Apo E) genotype and angiotensin-converting enzyme (ACE) insertion-deletion (Ins-Del) mutation and stroke was suggested. We investigated the association of Apo E4 and ACE Ins/Del genotypes with stroke risk and changes in serum lipids in 228 consecutive Tunisian stroke patients, and 323 age-and gender-matched controls. Comparable frequencies of ACE Ins/Del alleles were seen between patients and controls. The prevalence of Apo epsilon3 allele and Apo E3/E3 were lower (P < 0.001), while the frequency of Apo epsilon4 allele and epsilon4-containing genotypes (E3/E4 and E4/E4) were elevated (P < 0.001) among patients. Higher proportion of Apo E4-carrying + ACE Del/Del positive cases were seen in young (<50 years) patients (P = 0.012), and was associated with large vessel stroke (P = 0.035). Mean serum cholesterol, LDL, HDL, and triglycerides were comparable between E4-containing and no E4-containing and ACE Del/Del-positive patients. Apo E4 and ACE Del/Del genotype combination substantially increase stroke risk, supporting the notion that interactions of multiple gene variants influence stroke pathogenesis.

Stroke prevention in the high-risk patient

Strokes are increasing in number due to an ageing population and are largely preventable. In the highest risk patients, a 90% relative risk reduction for stroke is attainable by appropriately using all the measures proven to reduce stroke: smoking cessation, a Mediterranean diet, control of hypertension, anticoagulants or antiplatelet agents, lipid lowering drugs and appropriate carotid endarterectomy. Vitamin therapy to lower homocysteine and carotid stenting are additional measures that may yet prove beneficial. Diet, smoking cessation and appropriate carotid endarterectomy reduce stroke by more than do pharmacotherapies. Blood pressure control depends more on selecting appropriate therapy individualised for the patient, than on using any particular drug class. This review, therefore, places pharmacotherapy in perspective as part of, but not all of, stroke prevention.

Lipoprotein (a) and Stroke

Background and Purpose— The relationship between elevated lipoprotein (a) levels[Lp(a)] and stroke is controversial. We systematically reviewed the literature to determine whether Lp(a) is a risk factor for stroke.

Methods— We searched MEDLINE (1966 to 2006), EMBASE (1974 to 2006), and Google scholar for articles on Lp(a) and cerebrovascular disease. From potentially relevant references retrieved, we excluded uncontrolled studies, studies of children with stroke, studies investigating carotid atherosclerosis, and studies lacking adequate data.

Results— Thirty-one studies comprising 56 010 subjects with >4609 stroke events met all inclusion criteria and were included in the meta-analysis. In case-control studies (n=23 with 2600 strokes) unadjusted mean Lp(a) was higher in stroke patients (standardized mean difference, 0.39; 95% CI, 0.23 to 0.54) and was more frequently abnormally elevated (OR, 2.39; 95% CI, 1.57 to 3.63). Sensitivity analysis and meta-regression did not find any influence of study design, measurement period of Lp(a) in relationship to stroke episode, subtype, age, and sex to explain the substantial heterogeneity between studies (I 2 =83.7%; P <0.001). There was no evidence of publication bias. In nested case-control studies (n=3 with 364 strokes) Lp(a) was not a risk factor for incident stroke (OR, 1.04; 95% CI, 0.6 to 1.8). In prospective cohort studies (n=5 with >1645 strokes), incident stroke was more frequent in patients in the highest tertile of Lp(a) distribution compared with the lowest tertile of Lp(a) (RR, 1.22; 95% CI, 1.04 to 1.43). There was no publication bias or heterogeneity in the prospective studies (I 2 =0.00%; P =0.67).

Conclusion— This meta-analysis suggests that elevated Lp(a) is a risk factor for incident stroke.

Apolipoprotein A5 gene promoter region T-1131C polymorphism associates with elevated circulating triglyceride levels and confers susceptibility for development of ischemic stroke

The possible pathogenic role of triglycerides (TG) in the development of ischemic stroke is still under extensive investigation. Recently, apolipoprotein (apo)A5 gene promoter region T-1131C polymorphism has been shown to associate with elevated serum TG levels. In the current work, a total of 302 subjects were classified as being large vessel-associated, small vessel-associated, or belonging to a mixed group of ischemic stroke-affected patients. The level of TG was increased in all groups (p < 0.01). The apoA5-1131C allele frequency was approximately twofold in all groups of stroke patients compared with the controls (5 vs 10-12%; p < 0.05); and the apoA5-1131C allele itself was also found to associate with increased TG levels in all groups. In a multivariate logistic regression analysis model adjusted for differences in age, gender, serum cholesterol, hypertension, presence of diabetes mellitus, smoking and drinking habits, and ischemic heart disease, a significantly increased risk of developing stroke disease was found in patients carrying the apoA5-1131C allele (p < 0.05; odds ratio OR = 2.1 [1.3-4.7]); this association was also proven for all subtypes of the stroke. The results presented here suggest that the apoA5-1131C allele is an independent risk factor for the development of stroke. Being that apoA5 gene is under the control of the peroxisome proliferator-activated receptor alpha, theoretically, the current observations also can have long-term therapeutic consequences.

Stroke and Vascular Cognitive Impairment

Advances in stroke are occurring at an unprecedented pace, but often in disciplinary isolation and without optimal mechanisms for systematically translating, integrating and applying the findings.

Knowledge accrues in pieces, but is understood in patterns. To optimize knowledge acquisition and application, infrastructures and systems need to be set up along with appealing incentives. The approach needs to be transdisciplinary , going beyond the bounds of any given discipline, reciprocally translational , and transactional , meaning that the interchanges have to yield previously agreed benefits to the parties ( The Triple T Approach ). A new breed of leaders needs to be developed and nurtured to catalyze the process.

Opportunities abound. Stroke and most brain diseases share the same pathophysiological fundamental mechanisms. An integrated, systematic approach to these processes could yield not only greater understanding but new, common therapeutic targets for several diseases. Biphasic clinical trials could combine the best features of pragmatic and explanatory, randomized clinical trials. The greatest opportunity of all may be the largely under-explored and under-exploited borderlands between cerebrovascular and Alzheimer disease. One in three of us will have a stroke, become demented, or both. For each person who has a stroke or Alzheimer disease, two have some cognitive impairment short of dementia, often subclinical cerebrovascular disease on a substrate of Alzheimer changes. The fact that cerebrovascular and Alzheimer disease share the same risk factors, provide a great opportunity for prevention, if implemented at the “brain at risk” stage.

Systematically integrating what we know and evaluating what we do could spur progress. Research is not only an activity but an attitude. Making evaluation and incentives to excel part of the funding of all stroke activities would yield far ranging cumulative improvements in all aspects of stroke.

No system can replace the individual initiative, creativity and insights that lead to the great discoveries, but progress is not made by breakthroughs alone. No one’s work is so exalted that it cannot be improved, nor so humble that it has no value. We can all make a difference.

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.

Managing abnormal blood lipids: a collaborative approach

Current data and guidelines recommend treating abnormal blood lipids (ABL) to goal. This is a complex process and requires involvement from various healthcare professionals with a wide range of expertise. The model of a multidisciplinary case management approach for patients with ABL is well documented and described. This collaborative approach encompasses primary and secondary prevention across the lifespan, incorporates nutritional and exercise management as a significant component, defines the importance and indications for pharmacological therapy, and emphasizes the importance of adherence. Use of this collaborative approach for the treatment of ABL ultimately will improve cardiovascular and cerebrovascular morbidity and mortality.