Angiotensin-converting enzyme polymorphisms AND Alzheimer's disease susceptibility: An updated meta-analysis.

BACKGROUND: Many studies among different ethnic populations suggested that angiotensin converting enzyme (ACE) gene polymorphisms were associated with susceptibility to Alzheimer's disease (AD). However, the results remained inconclusive. In the present meta-analysis, we aimed to clarify the effect of ACE polymorphisms on AD risk using all available relevant data. METHODS: Systemic literature searches were performed using PubMed, Embase, Alzgene and China National Knowledge Infrastructure (CNKI). Relevant data were abstracted according to predefined criteria. RESULTS: Totally, 82 independent cohorts from 65 studies were included, focusing on five candidate polymorphisms. For rs1799752 polymorphism, in overall analyses, the insertion (I) allele conferred increased risk to AD compared to the deletion (D) allele (I vs. D: OR = 1.091, 95% CI = 1.007-1.181, p = 0.032); while the I carriers showed increased AD susceptibility compared with the D homozygotes (II + ID vs. DD: OR = 1.131, 95% CI = 1.008-1.270, p = 0.036). However, none of the positive results passed FDR adjustment. In subgroup analysis restricted to late-onset individuals, the associations between rs1799752 polymorphism and AD risk were identified using allelic comparison (OR = 1.154, 95% CI = 1.028-1.295, p = 0.015, FDR = 0.020), homozygotes comparison, dominant model and recessive model (II vs. ID + DD: OR = 1.272, 95% CI = 1.120-1.444, p < 0.001, FDR < 0.001). Nevertheless, no significant association could be revealed after excluding studies not in accordance with Hardy-Weinberg equilibrium (HWE). In North Europeans, but not in East Asians, the I allele demonstrated increased AD susceptibility compared to the D allele (OR = 1.096, 95% CI = 1.021-1.178, p = 0.012, FDR = 0.039). After excluding HWE-deviated cohorts, significant associations were also revealed under homozygotes comparison, additive model (ID vs. DD: OR = 1.266, 95% CI = 1.045-1.534, p = 0.016, FDR = 0.024) and dominant model (II + ID vs. DD: OR = 1.197, 95% CI = 1.062-1.350, p = 0.003, FDR = 0.018) in North Europeans. With regard to rs1800764 polymorphism, significant associations were identified particularly in subgroup of European descent under allelic comparison (T vs. C: OR = 1.063, 95% CI = 1.008-1.120, p = 0.023, FDR = 0.046), additive model and dominant model (TT + TC vs. CC: OR = 1.116, 95% CI = 1.018-1.222, p = 0.019, FDR = 0.046). But after excluding studies not satisfying HWE, all these associations disappeared. No significant associations were detected for rs4343, rs4291 and rs4309 polymorphisms in any genetic model. CONCLUSIONS: Our results suggested the significant but modest associations between rs1799752 polymorphism and risk to AD in North Europeans. While rs4343, rs4291 and rs4309 polymorphisms are unlikely to be major factors in AD development in our research.

MicroRNA-210-3p Targets RGMA to Enhance the Angiogenic Functions of Endothelial Progenitor Cells Under Hypoxic Conditions.

Endothelial progenitor cells (EPCs) are multipotential stem cells considered to have immense clinical value for revascularization. However, the clinical application of EPCs has been hampered by their clinical potency in ischemic anoxic environments. This study aimed to explore the effect of microRNA-210 (miR-210) on EPCs under oxygen-glucose deprivation (OGD) conditions. We generated a model of EPCs cultured under OGD conditions to simulate ischemia and explore the expression of miR-210 in vitro. With longer exposure to hypoxia, we found that miR-210-3p expression was highly upregulated in OGD groups compared to that in controls from 4 to 24 h, but not miR-210-5p. We then transfected a miR-210-3p mimic and inhibitor into EPCs, and after 24 h, we exposed them to OGD conditions for 4 h to simulate ischemia. We detected miR-210 by real-time polymerase chain reaction (RT-PCR) and tested the proliferation, migration, and tube formation of normal EPCs and OGD-treated EPCs by CCK-8, transwell chamber, and Matrigel assays, respectively. The direct targets of miR-210-3p were predicted using miRWalk. Compared to that in normal EPCs, higher miR-210-3p expression was found in OGD-treated EPCs (p < 0.05). Moreover, upregulation of miR-210-3p was found to promote proliferation, migration, and tube formation in EPCs under normal and OGD conditions (p < 0.05), whereas down-regulation inhibited these abilities in OGD-treated EPCs (p < 0.05). Repulsive guidance molecule A (RGMA), a negative regulator of angiogenesis, was predicted to be a target of miR-210-3p. Accordingly, upregulation of miR-210-3p was found to inhibit its expression at the protein level in OGD-treated EPCs, whereas downregulation of miR-210-3p inhibited its expression (p < 0.05). A dual-luciferase reporter system confirmed that RGMA is a direct target of miR-210-3p. MicroRNA-210-3p overexpression enhances the angiogenic properties of OGD-treated EPCs by inhibiting RGMA.

Comparison Study of ASCO and TOAST Classification System in Chinese Minor Stroke Patients.

BACKGROUND: Precise subtype classification based on underlying pathophysiology is important to prevent recurrent attack in minor stroke patients. A newly developed Atherosclerosis, Small vessel disease, Cardiac source, Others (ASCO) phenotypic classification system aims to characterize patients using different grades of evidence for stroke subtypes. However, this system has not been specifically applied to minor stroke population. In our study, the impact of using the newer ASCO criteria on minor stroke etiologies was investigated, and compared with that of Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification. METHODS: Consecutive patients with minor ischemic stroke (NIHSS ≤3) were assessed and subtyped by the ASCO and TOAST systems. Stroke etiologies were presented and compared. The McNemar test and k statistic were used to analyze the difference and concordance between the 2 algorithms, respectively. RESULTS: A total of 604 first-ever minor stroke patients were analyzed in the present study. Using TOAST classification, large artery atherosclerosis was the most frequent subtype (281, 46.5%), followed by small artery occlusion category (165, 27.3%). When ASCO was applied, 37 different profiles of stroke etiologies were identified. Using grade 1 of evidence, atherosclerosis (A1) was the most frequent subtype (308, 51.0%), followed by small vessel disease (S1, 178, 29.5%). Under consideration of grades 1 and 2, 239 (39.6%) patients were classified into more than 1 category. The ASCO system revealed determined etiologies in 104 of the 137 patients classified to cause undetermined subtype by TOAST classification. Good to very good accordance was observed between ASCO grade 1 and TOAST schemes across etiologic subtypes (κ = 0.719-0.832) except cause undetermined category (κ = 0.470). CONCLUSION: Application of ASCO decreased the proportion of patients assigned to cause undermined category compared to TOAST system. Comprehensive characteristics of ASCO system might be helpful in the personalized therapy or secondary prevention for individual patients in the future.

Restless legs syndrome in Chinese elderly people of an urban suburb in Shanghai: a community-based survey.

OBJECTIVE: The aim of the study is to investigate the prevalence rate of restless legs syndrome (RLS) in elderly Chinese people over 50 years of age in an urban suburb of Shanghai by a community-based study. METHODS: A 3-step survey was adopted including two telephone-based interviews and one face-to-face interview. We used questions based on four diagnostic criteria for RLS to perform the first telephone interview. The second telephone interview was performed by a sleep specialist to rule out the 'mimics' and secondary RLS. The final face-to-face interview was performed in the clinic for confirmation and examination. RESULTS: There were 2609 inhabitants in the Wuli Bridge suburb of Shanghai who responded to the first telephone interview (men 68.55±10.13 years of age and women 65.34±10.52 years of age, mean±SD). Eighteen people were finally diagnosed with RLS. In this sample, the overall prevalence rate of RLS was about 0.69% (95% confidence interval (CI): 0.41-1.09). CONCLUSION: Our study provided the first data about the prevalence rate of RLS in an urban suburb of Shanghai from mainland China, which is consistent with the low prevalence rate reported in other Asian countries.

2-methoxyestradiol attenuates autophagy activation after global ischemia.

BACKGROUND: Hypoxia inducible factor 1 (HIF-1) is a key transcriptional factor activated during cerebral ischemia, which regulates a great number of downstream genes, including those associated with cell death. In the present study, we aimed to test the hypothesis that post-ischemic HIF-1α up-regulation might promote autophagy activation; thereby, HIF-1α inhibitor 2ME2 might prevent neurons from ischemic injury through inhibiting autophagy. METHODS: Global ischemia was induced using the four-vessel occlusion model (4-VO) in Sprague-Dawley rats (male, 250-280g). 2-Methoxyestradiol (2ME2, 5mg/kg, i.p.) was administrated to down-regulate HIF-1α expression. Post-ischemic beclin-1 and LC3 protein expression was determined at different time points through Western blot assay. Neuronal injury was determined by cresyl violet staining and TUNEL staining in coronal histological sections. RESULTS: The expression of beclin-1 and the ratio of LC3-II/LC3-I increased significantly at 12 and 24 h after ischemia. 2ME2 could remarkably inhibit the up-regulation of beclin-1 and the increase of LC3-II/LC3-I ratio during reperfusion. Moreover, 2ME2 and 3-MA exhibited powerful protective effects against ischemic/reperfusion induced neuronal injury. CONCLUSIONS: This study confirmed that autophagy participated in post-ischemic neuronal injury. 2ME2, a HIF-1α inhibitor, might significantly decrease autophagy activation after cerebral ischemia and relieve post-ischemic neuronal injury. Our findings demonstrate that autophagy could be a potential target for neuronal protection after cerebral ischemia.

Starvation triggers Abeta42 generation from human umbilical vascular endothelial cells.

Cerebral amyloid angiopathy is a common feature in Alzheimer's disease (AD), which is characterized by amyloid deposit around brain vessels including capillaries. The origin of the amyloid protein of CAA remains controversial. In our work, we provide data to show that primary umbilical vein endothelial cells (HUVEC) harbor APP processing secretases and can produce Abeta(42) under starvation. Starvation can increase the secretion of Abeta(42) by altering the expression of beta-secretases (BACE1) and gamma-secretases (APH and PEN2). This process is regulated by macroautophagy. Suppression of macroautophagy induction by 3MA further increased the level of Abeta(42) produced under starvation in HUVECs. These results suggest that starvation-induced Abeta(42) secretion might contribute to the formation of CAA and hence vascular degeneration in AD.

Apolipoprotein E promoter polymorphisms and risk of Alzheimer's disease: evidence from meta-analysis.

Apolipoprotein E (APOE) promoter polymorphisms have long been linked to Alzheimer disease (AD) susceptibility, although the established data remains controversial. Using meta-analysis, our study aimed to clarify the nature of the genetic risks contributed by the three polymorphisms for developing AD. Medline, Embase, and Alzgene search identified 40 studies with 9,662 cases and 9.696 controls. Both -491A/T polymorphism (AA vs AT + TT: OR = 1.49, 95% CI=1.29-1.72) and -219T/G polymorphism (TT vs TG + GG: OR=1.30, 95% CI=1.10-1.55) showed a significant association with AD susceptibility; however, significant association was not identified in the analysis for -427T/C polymorphism (TT vs TC + CC: OR =1.03, 95% CI= 0.82-1.30). Among the APOE epsilon 4} carriers, the -491A homozygotes were at higher risk to develop AD compared with the -491T carriers (OR=1.42, 95% CI =1.15-1.76). For subjects carrying the -491AA genotype, the presence of the APOE epsilon4 allele increased the risk of AD 4.37-fold (95% CI=3.43-5.56). Subgroup analysis restricted to the late-onset or the Caucasian individuals revealed a similar association as that identified without restriction regarding -491A/T polymorphism. Our results confirm a significant but modest association between APOE promoter -491A/T and -219T/G polymorphisms and AD susceptibility.

Gene polymorphisms and risk of adult early-onset ischemic stroke: A meta-analysis.

INTRODUCTION: Genetic studies restricted to young adult ischemic stroke patients may help in excluding the potentially confounding variables encountered with advanced age; thus, allowing a more precise risk evaluation derived from the inherited mutations alone. Through meta-analysis, this study was conducted to determine the genetic risk contributed by each susceptibility gene polymorphism, particularly in adult early-onset ischemic stroke patients. MATERIALS AND METHODS: Electronic databases were searched for all the case-control studies relating to any candidate genes for ischemic stroke. The range of age was 18-50 years for cases. Fixed or random effects model was used depending on the heterogeneity between studies. RESULTS: Twenty-six studies were finally included in this meta-analysis; these studies focused on 7 candidate genes. A significant but modest association was identified for 2 polymorphisms, namely, methylenetetrahydrofolate reductase (MTHFR) C677T (OR = 1.44, 95% CI = 1.14-1.80) and apolipoprotein E (ApoE) epsilon2-4 (OR = 2.53, 95% CI = 1.71-3.73). Although the pooled analysis for platelet glycoprotein Ia (GPIa) C807T showed a positive association (OR = 1.50, 95% CI=1.10-2.05), the Egger's test indicated the existence of publication bias (t=5.27, P>|t|=0.034). CONCLUSIONS: Genetic abnormalities specific to homocysteine and lipid metabolism increase the risk for ischemic stroke at an early age. These data may offer important implications for future genetic association studies for stroke.

[The linkage disequilibrium of four loci in hepatic lipase promoter gene of cerebral infarction patients in Shanghai].

OBJECTIVE: To investigate the single nucleotide polymorphism (SNP), the distribution of their haplotypes and linkage disequilibrium of hepatic lipase (HL) gene promoter 250G/A, 514C/T, 710T/C and 763A/G in cerebral infarction patients of Shanghai. METHODS: Peripheral blood sample were collected from 133 patients with cerebral infarction and 112 healthy controls in Shanghai. The HL gene polymorphism was analyzed by polymerase chain reaction- restriction fragment length polymorphism. RESULTS: There were statistically significant differences in genotype and allele frequencies between the healthy controls and the patients with cerebral infarction in -250G/A and -514C/T genotypes and allele frequencies (all P < 0.05). However, there were no significant differences in genotype and allele frequencies in -710T/C and -763A/G between the healthy controls and the patients with cerebral infarction (all P > 0.05). Besides, there was a strong linkage disequilibrium between -250G/A and -514C/T, -710T/C, and -763A/G respectively, between -514C/T and -710T/C and -763A/G respectively, and between -710T/C and -763A/G. When the haplotypes were -250G/-514C, -250G/-710C, -250G/-763G, -514C/-710C, and 514C/-763G respectively, the frequencies in the cerebral infarction group were significantly lower than that in the healthy controls. When the haplotype was -250A/-514T, -250A/-710T, -250A/-710C, -250A/-763G, -514T/-710C, -514T/-763G, and -710T/-763G respectively, the frequencies in the cerebral infarction group were significantly higher than those in the healthy controls. CONCLUSION: There are significant haplotypes and linkage disequilibrium among the four SNPs of HL gene in the cerebral infarction patients of Shanghai. The haplotypes GC, GG, and CC lower the incidence rate of cerebral infarction, while the haplotypes AT, AC, AG, TC, and TG increase the incidence rate of cerebral infarction.