The Influence of OLR1 and PCSK9 Gene Polymorphisms on Ischemic Stroke: Evidence from a Meta-Analysis

PCSK9 E670G polymorphism increases risk of coronary artery disease in a Chinese Han population

OBJECTIVE

Coronary artery disease (CAD) is the leading cause of morbidity and mortality in the world. The proprotein convertase subtilisin/kexin type 9 (PCSK9) E670G polymorphism has been reported to be associated with variability in levels of low density lipoprotein cholesterol, a risk factor for CAD. However, the relationship between PCSK9 E670G and CAD is still not fully elucidated.

METHODS

A total of 225 patients and 189 control subjects were recruited in this study. DNA was extracted from peripheral blood samples and was genotyped by mass array method. In addition, we also conducted a meta-analysis of case-control studies to elucidate the relationship of CAD and polymorphism.

RESULTS

The GG genotype of PCSK9 E670G was associated with a higher risk of CAD [odds ratio (OR) 2.994, 95% confidence interval (CI): 1.174-7.631], even adjusting for risk factors (OR 2.794, 95% CI: 1.215-7.460). Logistic regression analysis showed that the dominant genetic model increased the CAD risk (OR 2.313, 95% CI: 1.070-6.983) after adjusting the confounding factors. Meta-analysis results of 13 studies revealed that PCSK9 E670G polymorphism was correlated with CAD risk under different genetic models.

CONCLUSION

Our results demonstrated that PCSK9 E670G genotype was associated with a high risk of CAD.

LOX-1 variants modulate the severity of cardiovascular disease: state of the art and future directions

Atherosclerosis is one of the major causes of cerebral infarction and many other ischemic cardio-cerebrovascular diseases. Although large randomized clinical trials have highlighted the impressive benefits of lipid-lowering therapies, the 50-70% of patients who have achieved their lipid-lowering goal remain at high cardiovascular disease risk. For this reason, there is a need to investigate other markers of atherosclerosis progression. LOX-1 is a scavenger receptor that accepts oxidized low-density lipoproteins as major ligand and internalizes it by endocytosis favoring its retention in subendothelial layer and triggering a wide variety of proatherogenic events. However, other factors such as cytokines, shear stress, and advanced glycation end-products can upregulate LOX-1. LOX-1 is encoded by the OLR1 gene, located in the p12.3-p13 region of chromosome 12. OLR1 gene has different isoforms induced by splicing, or single-nucleotide polymorphisms (SNPs). According to some authors, the expression of these isoforms induces a different effect on atherosclerosis and cardiovascular disease. In particular, LOXIN, an isoform lacking part of the functional domain, exerts an important role in atherosclerosis protection. In other cases, studies on SNPs showed an association with more severe forms, like in the case of 3'UTR polymorphisms. The knowledge of these variants can give rise to the development of new preventive therapies and can lead to the identification of subjects at greater risk of cardiovascular event. In this review, we reported the state of the art regarding SNPs with known effects on OLR1 splicing and how LOX-1 variants modulate the severity of cardiovascular disease.

Unusual effects of PCSK9 E670G (rs505151) variation in patients with in-stent restenosis: Variable effects on restenosis risk according to concomitant chronic conditions

Recent reports showing that neo-atherosclerosis formation in stented coronary artery is characterized by the accumulation of lipid-laden macrophages within the neointima has strengthened the possibility that elevated low-density lipoprotein (LDL)-cholesterol may be a risk factor for in-stent restenosis (ISR). Protein Convertase Subtilisin/Kexin-9 (PCSK9) protein plays an important role in cholesterol metabolism by degrading of LDL receptors. The gain-of-function E670G (rs505151) mutation of the PCSK9 gene is a well-known genetic risk factor for hypercholesterolemia. This study evaluated for the first time the association of the E670G variation with the serum lipids, PCSK9 levels and concomitant diseases on the ISR risk. The study included 109 ISR, and 82 Non-ISR patients, based on the results of coronary angiography. Genotypes were determined using the real-time PCR and serum PCSK9 levels were measured by ELISA technique. The rare G allele of PCSK9 E670G (p < 0.05), hyperlipidemia (HL) (p < 0.001), and type 2 diabetes (T2DM) (p < 0.01) were associated with increased risk for ISR. In hyperlipidemic conditions, the E670G-G allele was associated with hypercholesterolemia and a higher risk of ISR (p < 0.001), while the E670G-AA genotype has been associated with a high prevalence of T2DM and hypertension. In addition, diabetic ISRs had higher serum PCSK9 levels (p < 0.05) and the E670G-AA genotype was associated with increased levels of diabetes markers. Our results indicated that the unusual effects of both G allele and AA genotype of the PCSK9 E670G variation may be involved in the risk of ISR in association with concomitant metabolic diseases.

Function of proprotein convertase subtilisin/kexin type 9 and its role in central nervous system diseases: An update on clinical evidence

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has attracted lots of attention in preventing the clearance of plasma low-density lipoprotein cholesterol (LDL-C). PCSK9 inhibitors are developed to primarily reduce the cardiovascular risk by lowering LDL-C level. Recently, a number of pleiotropic extrahepatic functions of PCSK9 beyond the regulation of cholesterol metabolism, particularly its effects on central nervous system (CNS) diseases have been increasingly identified. Emerging clinical evidence have revealed that PCSK9 may play a significant role in neurocognition, depression, Alzheimer's disease, and stroke. The focus of this review is to elucidate the functions of PCSK9 and highlight the effects of PCSK9 in CNS diseases, with the aim of identifying the potential risks that may arise from low PCSK9 level (variant or inhibitor) in the clinical practice.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) in the central nervous system

The gene encoding proprotein convertase subtilisin/kexin type 9 (PCSK9) and its protein product have been widely studied for their role in cholesterol and lipid metabolism. PCSK9 increases the rate of metabolic degradation of low-density lipoprotein receptors, preventing the diffusion of low-density lipoprotein (LDL) from plasma into cells and contributes to high lipoprotein-bound cholesterol levels in the plasma. While most research has focused on the regulation and disease relevance of PCSK9 to the cardiovascular system and lipid metabolism, there is a growing body of evidence that PCSK9 plays a crucial role in pathogenic processes in other organ systems, including the central nervous system. PCSK9's impact on the brain is not yet fully understood, though several recent studies have sought to illuminate its impact on various neurodegenerative and psychiatric disorders, as well as its connection with ischemic stroke. Cerebral PCSK9 expression is low but is highly upregulated during disease states. Among others, PCSK9 is known to play a role in neurogenesis, neural cell differentiation, central LDL receptor metabolism, neural cell apoptosis, neuroinflammation, Alzheimer's Disease, Alcohol Use Disorder, and stroke. The PCSK9 gene contains several polymorphisms, including both gain-of-function and loss-of-function mutations which profoundly impact normal PCSK9 signaling and cholesterol metabolism. Gain-of-function mutations lead to persistent hypercholesterolemia and poor health outcomes, while loss-of-function mutations generally lead to hypocholesterolemia and may serve as a protective factor against diseases of the liver, cardiovascular system, and central nervous system. Recent genomic studies have sought to identify the end-organ effects of such mutations and continue to identify evidence of a much broader role for PCSK9 in extrahepatic organ systems. Despite this, there remain large gaps in our understanding of PCSK9, its regulation, and its effects on disease risk outside the liver. This review, which incorporates data from a wide range of scientific disciplines and experimental paradigms, is intended to describe PCSK9's role in the central nervous system as it relates to cerebral disease and neuropsychiatric disorders, and to examine the clinical potential of PCSK9 inhibitors and genetic variation in the PCSK9 gene on disease outcomes, including neurological and neuropsychiatric disease.

Integrated bioinformatics analysis identifies shared immune changes between ischemic stroke and COVID 19

Although COVID-19 is primarily a respiratory disease, its neurological complications, such as ischemic stroke (IS), have aroused growing concerns and reports. However, the molecular mechanisms that underlie IS and COVID-19 are not well understood. Therefore, we implemented transcriptomic analysis from eight GEO datasets consist of 1191 samples to detect common pathways and molecular biomarkers in IS and COVID-19 that help understand the linkage between them. Differentially expressed genes (DEGs) were detected for IS and COVID-19 separately for finding shared mechanisms and we found that immune-related pathways were outlined with statistical significance. JAK2, which was identified as a hub gene, was supposed to be a potential therapeutic gene targets during the immunological process of COVID-19 and IS. Besides, we found a decrease in the proportion of CD8+ T and T helper 2 cells in the peripheral circulation of both COVID and IS patients, and NCR3 expression was significantly correlated with this change. In conclusion, we demonstrated that transcriptomic analyses reported in this study could make a deeper understanding of the common mechanism and might be promising for effective therapeutic for IS and COVID-19.

Lipoprotein receptor signalling in atherosclerosis

The founding member of the lipoprotein receptor family, low-density lipoprotein receptor (LDLR) plays a major role in the atherogenesis through the receptor-mediated endocytosis of LDL particles and regulation of cholesterol homeostasis. Since the discovery of the LDLR, many other structurally and functionally related receptors have been identified, which include low-density lipoprotein receptor-related protein (LRP)1, LRP5, LRP6, very low-density lipoprotein receptor, and apolipoprotein E receptor 2. The scavenger receptor family members, on the other hand, constitute a family of pattern recognition proteins that are structurally diverse and recognize a wide array of ligands, including oxidized LDL. Among these are cluster of differentiation 36, scavenger receptor class B type I and lectin-like oxidized low-density lipoprotein receptor-1. In addition to the initially assigned role as a mediator of the uptake of macromolecules into the cell, a large number of studies in cultured cells and in in vivo animal models have revealed that these lipoprotein receptors participate in signal transduction to modulate cellular functions. This review highlights the signalling pathways by which these receptors influence the process of atherosclerosis development, focusing on their roles in the vascular cells, such as macrophages, endothelial cells, smooth muscle cells, and platelets. Human genetics of the receptors is also discussed to further provide the relevance to cardiovascular disease risks in humans. Further knowledge of the vascular biology of the lipoprotein receptors and their ligands will potentially enhance our ability to harness the mechanism to develop novel prophylactic and therapeutic strategies against cardiovascular diseases.

Physiology and role of PCSK9 in vascular disease: Potential impact of localized PCSK9 in vascular wall

Proprotein convertase subtilisin/kexin type-9 (PCSK9), a member of the proprotein convertase family, is an important drug target because of its crucial role in lipid metabolism. Emerging evidence suggests a direct role of localized PCSK9 in the pathogenesis of vascular diseases. With this in our consideration, we reviewed PCSK9 physiology with respect to recent development and major studies (clinical and experimental) on PCSK9 functionality in vascular disease. PCSK9 upregulates low-density lipoprotein (LDL)-cholesterol levels by binding to the LDL-receptor (LDLR) and facilitating its lysosomal degradation. PCSK9 gain-of-function mutations have been confirmed as a novel genetic mechanism for familial hypercholesterolemia. Elevated serum PCSK9 levels in patients with vascular diseases may contribute to coronary artery disease, atherosclerosis, cerebrovascular diseases, vasculitis, aortic diseases, and arterial aging pathogenesis. Experimental models of atherosclerosis, arterial aneurysm, and coronary or carotid artery ligation also support PCSK9 contribution to inflammatory response and disease progression, through LDLR-dependent or -independent mechanisms. More recently, several clinical trials have confirmed that anti-PCSK9 monoclonal antibodies can reduce systemic LDL levels, total nonfatal cardiovascular events, and all-cause mortality. Interaction of PCSK9 with other receptor proteins (LDLR-related proteins, cluster of differentiation family members, epithelial Na⁺ channels, and sortilin) may underlie its roles in vascular disease. Improved understanding of PCSK9 roles and molecular mechanisms in various vascular diseases will facilitate advances in lipid-lowering therapy and disease prevention.

Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) in the Brain and Relevance for Neuropsychiatric Disorders

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has long been studied in the liver due to its regulation of plasma low-density lipoprotein cholesterol (LDL-C) and its causal role in familial hypercholesterolemia. Although PCSK9 was first discovered in cerebellar neurons undergoing apoptosis, its function in the central nervous system (CNS) is less clear. PCSK9 has been shown to be involved in neuronal differentiation, LDL receptor family metabolism, apoptosis, and inflammation in the brain, but in vitro and in vivo studies offer contradictory findings. PCSK9 expression in the adult brain is low but is highly upregulated during disease states. Cerebral spinal fluid (CSF) PCSK9 concentrations are correlated with neural tube defects and neurodegenerative diseases in human patients. Epigenetic studies reveal that chronic alcohol use may modulate methylation of the PCSK9 gene and genetic studies show that patients with gain-of-function PCSK9 variants have higher LDL-C and an increased risk of ischemic stroke. Early safety studies of the PCSK9 inhibitors evolocumab and alirocumab, used to treat hypercholesterolemia, hinted that PCSK9 inhibition may negatively impact cognition but more recent, longer-term clinical trials found no adverse neurocognitive events. The purpose of this review is to elucidate the role of PCSK9 in the brain, particularly its role in disease pathogenesis.

Association of NOTCH3 Gene Polymorphisms with Ischemic Stroke and its Subtypes: A Meta-Analysis

Background and objectives: NOTCH3 gene variations play a significant role in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). However, the role of NOTCH3 gene polymorphisms in the risk of ischemic stroke, and its subtypes such as atherothrombotic or lacunar strokes, remains unclear. Aims: Hence, we carried out a meta-analysis to examine whether the NOTCH3 rs1043994, rs1044009 and rs3815188 polymorphisms are associated with ischemic stroke and its major subtypes. Materials and Methods: All relevant studies were systematically screened and meta-analyzed using Review Manager (Revman) version 5.3. The strength of the association between NOTCH3 polymorphisms and ischemic stroke risk and its subtypes were measured as odds ratios and 95% confidence intervals, under different genetic models. Results: A total of ten studies were identified, five of which considered NOTCH3 rs1043994 (2077 cases/2147 controls), five of which considered NOTCH3 rs1044009 (2315 cases/3053 controls), and nine of which considered NOTCH3 rs3815188 (2819 cases/2769 controls). These studies were meta-analyzed for their association with ischemic stroke risk. Four studies (874 cases/2002 controls) of the NOTCH3 rs3815188 polymorphism and three studies of the NOTCH3 rs1043994 (643 cases/1552 controls) polymorphism were meta-analyzed for lacunar stroke risk. Three studies (1013 cases/1972 controls) of the NOTCH3 rs3815188 polymorphism were meta-analyzed for atherothrombotic stroke risk. The meta-analysis results showed a lack of association between all of the studied polymorphisms and the risk of ischemic stroke and its major subtypes (i.e., atherothrombotic and lacunar). Conclusions: NOTCH3 polymorphisms are not significantly associated with the risk of ischemic stroke and its subtypes (p < 0.05).

Meta-Analysis of Factor V, Factor VII, Factor XII, and Factor XIII-A Gene Polymorphisms and Ischemic Stroke

Numerous studies examined the association between factors FV, FVII, FXII, and FXIII-A gene polymorphisms and ischemic stroke, but conclusive evidence is yet to be obtained. Thus, this meta-analysis aimed to investigate the novel association of FV rs1800595, FVII rs5742910, FXII rs1801020, and FXIII-A rs5982 and rs3024477 polymorphisms with ischemic stroke risk. A systematic review was performed on articles retrieved before June 2018. Relevant data were extracted from eligible studies and meta-analyzed using RevMan version 5.3. The strength of association between studied polymorphisms and ischemic stroke risk was calculated as odds ratios and 95% confidence intervals, by applying both fixed- and random-effect models. A total of 25 studies involving 6100 ischemic stroke patients and 9249 healthy controls were incorporated in the final meta-analysis model. Specifically, rs1800595, rs5742910, rs1801020, rs5982, and rs3024477 consisted of 673, 3668, 922, 433, and 404 cases, as well as 995, 4331, 1285, 1321, and 1317 controls, respectively. The pooled analysis indicated that there was no significant association of FV rs1800595, FVII rs5742910, FXII rs1801020, FXIII-A rs5982, and FXIII-A rs3024477 polymorphisms with ischemic stroke risk, under any genetic models (dominant, recessive, over-dominant, and allelic). The present meta-analysis concluded that FV rs1800595, FVII rs5742910, FXII rs1801020, and FXIII-A rs5982 and rs3024477 polymorphisms are not associated with ischemic stroke risk.

Metabolomics and Lipidomics of Ischemic Stroke

Ischemic stroke is a sudden loss of brain function due to the reduction of blood flow. Brain tissues cease to function with subsequent activation of the ischemic cascade. Metabolomics and lipidomics are modern disciplines that characterize the metabolites and lipid components of a biological system, respectively. Because the pathogenesis of ischemic stroke is heterogeneous and multifactorial, it is crucial to establish comprehensive metabolomic and lipidomic approaches to elucidate these alterations in this disease. Fortunately, metabolomic and lipidomic studies have the distinct advantages of identifying tissue/mechanism-specific biomarkers, predicting treatment and clinical outcome, and improving our understanding of the pathophysiologic basis of disease states. Therefore, recent applications of these analytical approaches in the early diagnosis of ischemic stroke were discussed. In addition, the emerging roles of metabolomics and lipidomics on ischemic stroke were summarized, in order to gain new insights into the mechanisms underlying ischemic stroke and in the search for novel metabolite biomarkers and their related pathways.

Molecular genetic studies in Saudi population; identified variants from GWAS and meta-analysis in stroke

INTRODUCTION

Stroke is a multifactorial and heterogeneous disorder, correlates with heritability and considered as one of the major diseases. The prior reports performed the variable models such as genome-wide association studies (GWAS), replication, case-control, cross-sectional and meta-analysis studies and still, we lack diagnostic marker in the global world. There are limited studies were carried out in Saudi population, and we aim to investigate the molecular association of single nucleotide polymorphisms (SNPs) identified through GWAS and meta-analysis studies in stroke patients in the Saudi population.

METHODS

In this case-control study, we have opted gender equality of 207 cases and 207 controls from the capital city of Saudi Arabia in King Saud University Hospital. The peripheral blood (5 ml) sample will be collected in two different vacutainers, and three mL of the coagulated blood will be used for lipid analysis (biochemical tests) and two mL will be used for DNA analysis (molecular tests). Genomic DNA will be extracted with the collected blood samples, and specific primers will be designed for the opted SNPs (SORT1-rs646218 and OLR1-rs11053646 polymorphisms) and PCR-RFLP will be performed and randomly DNA sequencing will be carried out to cross check the results.

RESULTS

The rs646218 and rs11053646 polymorphisms were significantly associated with allele, genotype and dominant models with and without crude odds ratios (OR's) and Multiple logistic regression analysis (p < 0.05). Correlation between lipid profile and genotypes has confirmed the significant relation between triglycerides and rs646218 and rs1105364 6polymorphisms. However, rs11053646 polymorphism was correlated with HDLC (p = 0.04). Genotypes were examined in both males' vs. males and females' vs. females in cases and control and we concluded that in rs11053646 polymorphisms with male subjects compared between cases and controls found to be associated with dominant model heterozygote genotypes (p < 0.05).

CONCLUSION

The results of the current study confirmed the SORT1 and OLR1 SNPs were associated in the Saudi population. The current results were in the association with the prior study results documented through GWAS and meta-analysis association. However, other ethnic population studies should be performed to rule out in the human hereditary diseases.

Recent advances in the management of transient ischemic attacks

Significant advances in our understanding of transient ischemic attack (TIA) have taken place since it was first recognized as a major risk factor for stroke during the late 1950's. Recently, numerous studies have consistently shown that patients who have experienced a TIA constitute a heterogeneous population, with multiple causative factors as well as an average 5-10% risk of suffering a stroke during the 30 days that follow the index event. These two attributes have driven the most important changes in the management of TIA patients over the last decade, with particular attention paid to effective stroke risk stratification, efficient and comprehensive diagnostic assessment, and a sound therapeutic approach, destined to reduce the risk of subsequent ischemic stroke. This review is an outline of these changes, including a discussion of their advantages and disadvantages, and references to how new trends are likely to influence the future care of these patients.

Cerebrovascular gene expression in spontaneously hypertensive rats

Hypertension is a hemodynamic disorder and one of the most important and well-established risk factors for vascular diseases such as stroke. Blood vessels exposed to chronic shear stress develop structural changes and remodeling of the vascular wall through many complex mechanisms. However, the molecular mechanisms involved are not fully understood. Hypertension-susceptible genes may provide a novel insight into potential molecular mechanisms of hypertension and secondary complications associated with hypertension. The aim of this exploratory study was to identify gene expression differences in the middle cerebral arteries between 12-week-old male spontaneously hypertensive rats and their normotensive Wistar-Kyoto rats using an Affymetrix whole-transcriptome expression profiling. Quantitative PCR and western blotting were used to verify genes of interest. 169 genes were differentially expressed in the middle cerebral arteries from hypertensive compared to normotensive rats. The gene expression of 72 genes was decreased and the gene expression of 97 genes was increased. The following genes with a fold difference ≥1.40 were verified by quantitative PCR; Postn, Olr1, Fas, Vldlr, Mmp2, Timp1, Serpine1, Mmp11, Cd34, Ptgs1 and Ptgs2. The gene expression of Postn, Olr1, Fas, Vldlr, Mmp2, Timp1 and Serpine1 and the protein expression of LOX1 (also known as OLR1) were significantly increased in the middle cerebral arteries from spontaneously hypertensive rats compared to Wistar-Kyoto rats. In conclusion, the identified genes in the middle cerebral arteries from spontaneously hypertensive rats could be possible mediators of the vascular changes and secondary complications associated with hypertension. This study supports the selection of key genes to investigate in the future research of hypertension-induced end-organ damage.

The impact of APOA5, APOB, APOC3 and ABCA1 gene polymorphisms on ischemic stroke: Evidence from a meta-analysis

BACKGROUND AND AIMS

Genetic studies have been reported on the association between APOA5, APOB, APOC3 and ABCA1 gene polymorphisms and ischemic stroke, but results remain controversial. Hence, this meta-analysis aimed to infer the causal relationships of APOA5 (rs662799, rs3135506), APOB (rs693, rs1042031, rs1801701), APOC3 (rs4520, rs5128, rs2854116, rs2854117) and ABCA1 rs2230806 with ischemic stroke risk.

METHODS

A systematic review was performed for all the articles retrieved from multiple databases, up until March 2017. Data were extracted from all eligible studies, and meta-analysis was carried out using RevMan 5.3 and R package 3.2.1. The strength of association between each studied polymorphism and ischemic stroke risk was measured as odds ratios (ORs) and 95% confidence intervals (CIs), under fixed- and random-effect models.

RESULTS

A total of 79 studies reporting on the association between the studied polymorphisms and ischemic stroke risk were identified. The pooled data indicated that all genetic models of APOA5 rs662799 (ORs = 1.23-1.43), allelic and over-dominant models of APOA5 rs3135506 (ORs = 1.77-1.97), APOB rs1801701 (ORs = 1.72-2.13) and APOB rs1042031 (ORs = 1.66-1.88) as well as dominant model of ABCA1 rs2230806 (OR = 1.31) were significantly associated with higher risk of ischemic stroke. However, no significant associations were observed between ischemic stroke and the other five polymorphisms, namely ApoB (rs693) and APOC3 (rs4520, rs5128, rs2854116 and rs2854117), under any genetic model.

CONCLUSIONS

The present meta-analysis confirmed a significant association of APOA5 rs662799 CC, APOA5 rs3135506 CG, APOB rs1801701 GA, APOB rs1042031 GA and ABCA1 rs2230806 GG with increased risk of ischemic stroke.

LOX-1 in Atherosclerosis and Myocardial Ischemia: Biology, Genetics, and Modulation

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), one of the scavenger receptors for oxidized low-density lipoprotein cholesterol (ox-LDL), plays a crucial role in the uptake of ox-LDL by cells in the arterial wall. Mounting evidence suggests a role for LOX-1 in various steps of the atherosclerotic process, from initiation to plaque destabilization. Studies of the genetic structure of LOX-1 have also uncovered various genetic polymorphisms that could modulate the risk of atherosclerotic cardiovascular events. As evidence supporting the vital role of LOX-1 in atherogenesis keeps accumulating, there is growing interest in LOX-1 as a potential therapeutic target. This review discusses the discovery and genetics of LOX-1; describes existing evidence supporting the role of LOX-1 in atherogenesis and its major complication, myocardial ischemia; and summarizes LOX-1 modulation by some naturally occurring compounds and efforts toward development of small molecules and biologics that could be of therapeutic use.

Polymorphisms of MTHFR, eNOS, ACE, AGT, ApoE, PON1, PDE4D, and Ischemic Stroke: Meta-Analysis

INTRODUCTION

The association between ischemic stroke and genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR; 677C>T and 1298A>C), endothelial nitric oxide synthase (eNOS; -786T>C, +894G>T, and variable number tandem repeat [VNTR]), phosphodiesterase 4D (PDE4D; SNPs 83 and 87), angiotensin-converting enzyme (ACE) I/D, angiotensinogen (AGT) 235M>T, paraoxonase 1 (PON1) 192Q>R, and apolipoprotein E (ApoE) ε2ε3ε4 remains inconclusive. Therefore, this updated meta-analysis aimed to clarify the presumed influence of genetic polymorphisms on ischemic stroke by meta-analyzing the comprehensive coverage of all individual association studies.

METHODS

All case-control studies published in different languages such as English, Japanese, Korean, Spanish, Chinese, Hungarian, Ukrainian, or Russian were identified from databases. The pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated via fixed- and random-effect models. Sensitivity analysis, heterogeneity test, Hardy Weinberg Equilibrium, and Egger's regression analyses were performed in this study.

RESULTS

A total of 490 case-control studies with 138,592 cases and 159,314 controls were included in this meta-analysis. Pooled ORs from all the genetic models indicated that MTHFR 677TT and 1298CC, eNOS +894TT and VNTR, PDE4D SNP 83, ACE DD, AGT 235TT, PON1 192RR, and ApoE ε4 polymorphisms were increasing the risks of ischemic stroke. Nevertheless, PDE4D SNP 87 and eNOS -786T>C polymorphisms are not associated with ischemic stroke risks.

CONCLUSIONS

Hence, the evidence from this meta-analysis concluded that MTHFR (677C>T and 1298A>C), eNOS (+894G>T and VNTR), PDE4D SNP 83, ACE I/D, AGT 235M>T, PON1 192Q>R, and ApoE ε2ε3ε4 polymorphisms predispose individuals to ischemic stroke.

What is the impact of PCSK9 rs505151 and rs11591147 polymorphisms on serum lipids level and cardiovascular risk: a meta-analysis

Background

PCSK9 rs505151 and rs11591147 polymorphisms are identified as gain- and loss-of-function mutations, respectively. The effects of these polymorphisms on serum lipid levels and cardiovascular risk remain to be elucidated.

Methods

In this meta-analysis, we explored the association of PCSK9 rs505151 and rs11591147 polymorphisms with serum lipid levels and cardiovascular risk by calculating the standardized mean difference (SMD) and odds ratios (OR) with 95% confidence intervals (CI).

Results

Pooled results analyzed under a dominant genetic model indicated that the PCSK9 rs505151 G allele was related to higher levels of triglycerides (SMD: 0.14, 95% CI: 0.02 to 0.26, P = 0.021, I² = 0) and low-density lipoproteins cholesterol (LDL-C) (SMD: 0.17, 95% CI: 0.00 to 0.35, P = 0.046, I² = 75.9%) and increased cardiovascular risk (OR: 1.50, 95% CI: 1.19 to 1.89, P = 0.0006, I² = 48%). The rs11591147 T allele was significantly associated with lower levels of total cholesterol (TC) and LDL-C (TC, SMD: -0.45, 95% CI: -0.57 to −0.32, P = 0.000, I² = 0; LDL-C, SMD: -0.44, 95% CI: -0.55 to −0.33, P = 0.000, I² = 0) and decreased cardiovascular risk (OR: 0.77, 95% CI: 0.60 to 0.98, P = 0.031, I² = 59.9) in Caucasians.

Conclusions

This study indicates that the variant G allele of PCSK9 rs505151 confers increased triglyceride (TG) and LDL-C levels, as well as increased cardiovascular risk. Conversely, the variant T allele of rs11591147 protects carriers from cardiovascular disease susceptibility and lower TC and LDL-C levels in Caucasians. These findings provide useful information for researchers interested in the fields of PCSK9 genetics and cardiovascular risk prediction not only for designing future studies, but also for clinical and public health applications.

Disease burden and the role of pharmacogenomics in African populations

Background

The burden of communicable and non-communicable diseases in Sub-Saharan Africa poses a challenge in achieving quality healthcare. Although therapeutic drugs have generally improved health, their efficacy differs from individual to individual. Variability in treatment response is mainly because of genetic variants that affect the pharmacokinetics and pharmacodynamics of drugs.

Method

The intersection of disease burden and therapeutic intervention is reviewed, and the status of pharmacogenomics knowledge in African populations is explored.

Results

The most commonly studied variants with pharmacogenomics relevance are discussed, especially in genes coding for enzymes that affect the response to drugs used for HIV, malaria, sickle cell disease and cardiovascular diseases.

Conclusions

The genetically diverse African population is likely to benefit from a pharmacogenomics-based healthcare approach, especially with respect to reduction of drug side effects, and separation of responders and non-responders leading to optimized drug choices and doses for each patient.

Upregulation of OLR1 and IL17A genes and their association with blood glucose and lipid levels in femoropopliteal artery disease

Oxidized low-density lipoprotein receptor 1 (OLR1) and interleukin 17A (IL17A) have pro-inflammatory roles in the development of cardiovascular disorders. The present study evaluated the association of OLR1 and IL17A and their polymorphisms with the development of femoropopliteal (FP) artery disease. The mRNA expression of OLR1 and IL17A in peripheral blood mononuclear cells as well as the frequency of OLR1 rs11053646 and IL17A rs8193037 and rs3819025 polymorphisms were assessed by polymerase chain reaction in 70 patients with FP artery disease and 80 age-matched disease-free controls. Furthermore, the levels of plasma cytokines were assessed by multiplex immunoassay. OLR1 and IL17A mRNA expression was significantly higher in patients with FP artery disease compared with that in controls (P<0.001). No significant difference was observed in the genotypic frequencies of OLR1 rs11053646 (P=0.87) or in IL17A rs8193037 and rs3819025 (P=0.80 and 0.92, respectively) polymorphisms between patients with FP artery disease and controls. Plasma IL4, -6, -10, -22, -31 and -33 as well as soluble cluster of differentiation 40 ligand and tumor necrosis factor-α levels were significantly increased among FP artery disease patients compared with controls (P<0.05). Furthermore, OLR1 expression was positively correlated with triglyceride (r=0.463, P<0.001), low-density lipoprotein cholesterol (r=0.507, P<0.001) and total cholesterol levels (r=0.357, P=0.006) in patients with FP artery disease. To the best of our knowledge, the present study was the first to identify an association between OLR1 and IL17A genes and FP artery disease. OLR1 and IL17A mRNA transcripts may be associated with blood lipid parameters and with the development of FP artery disease.

Decreased serum PCSK9 levels after ischaemic stroke predict worse outcomes

BACKGROUND

Soluble mediators have been investigated to predict the prognosis of acute ischaemic stroke (AIS). Among them, proprotein convertase subtilisin/kexin type 9 (PCSK9) might have both clinical and pathophysiological relevance.

MATERIALS AND METHODS

All available serum samples from a cohort of patients with first AIS (n = 72) were tested for PCSK9 and included in this substudy analysis. The primary endpoint investigated the predictive value of early PCSK9 level variations (ΔPCSK9) from AIS onset to day 7 or from day 1 to day 7, towards a 90-day outcome by modified Rankin Scale (mRS). The secondary endpoint explored the association between ΔPCSK9 and the risk of major adverse cardiovascular events (MACEs).

RESULTS

Decreased serum PCSK9 levels at days 1 and 7 were associated with poor clinical outcomes at day 90. At the cut-off point identified by ROC curve analysis (-61·28 ng/mL), ΔPCSK9 day 7-day 1 predicted a poor mRS at day 90 after AIS. ΔPCSK9 day 7-day 1 ≤ -61·28 ng/mL was associated with an increased rate of MACEs.

CONCLUSION

A decrease in PCSK9 levels was a predictor for poor outcome and increased MACEs after AIS. Additional studies targeting post-AIS PCSK9 levels and activity are required to clarify the prognostic and pathophysiological relevance of PCSK9 after AIS.

Genetic associations of the thyroid stimulating hormone receptor gene with Graves diseases and Graves ophthalmopathy: A meta-analysis

Graves' disease (GD) is a common thyroid disease, and Graves ophthalmopathy(GO) is the most common extra-thyroidal manifestation of GD. Genetic associations of the thyroid stimulating hormone receptor (TSHR) gene with GD and GO have been studied in different population groups for a long time. We aimed to obtain a more precise estimation of the effects of TSHR single nucleotide polymorphisms (SNPs) on GD/GO using a meta-analysis. Publications were searched on Pub Med and EMBASE up to December 30, 2015. Eight studies involving three SNPs (rs179247, rs12101255, and rs2268458), which included 4790 cases and 5350 controls, met the selection criteria. The pooled odds ratios (OR) and the 95% confidence intervals (CI) were estimated. SNPs rs179247 (dominant model [GG + GA vs. AA]: OR = 0.66, 95%CI: 0.61-0.73, P = 0.000, I(2) = 0%) and rs12101255 (dominant model [TT + TC vs. CC]: OR = 1.67, 95%CI: 1.53-1.83, P = 0.000, I(2) = 0%) were significantly associated with GD in all of the genetic models. TSHR rs12101255 and rs2268458 polymorphisms had no association between GO and GD (GD without GO). The results indicate that rs179247 and rs12101255 are likely to be genetic biomarkers for GD. Further studies with different population groups and larger sample sizes are needed to confirm the genetic associations of the TSHR gene with GD/GO.

Recent Advances in the Genetics of Hypertension

Hypertension is a silent killer worldwide, caused by both genetic and environmental factors. Until now, genetic and genomic association studies of hypertension are reporting different degree of association on hypertension. Hence, it is essential to gather all the available information on the reported genetic loci and to determine if any biomarker(s) is/are significantly associated with hypertension. Current review concluded the potential biomarkers for hypertension, with regards to electrolyte and fluid transports, as well as sodium/potassium ions homeostasis, which are supported by the results of case-controls and meta-analyses.