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.

Background: The expression of miR-140-5p increased in the brain tissue of a bilateral common carotid artery ligation model, while the overexpression of miR-140-5p significantly decreased the number of neurons. The luciferase report experiment in the previous study proved that miR-140-5p negatively regulated one of the potential targets of Prospero-related homeobox 1 (Prox1). Therefore, we want to investigate the effect of miR-140-5p on the proliferation and differentiation of neural stem cells (NSCs) and the underlying mechanism.Methods: Primary NSCs were extracted from pregnant ICR mice aged 16-18 days and induced to differentiate. After transient transfection with miR-140-5p mimic and inhibitor into NSCs, the cells were divided into five groups: blank, mimic normal control, mimic, inhibitor normal control, and inhibitor. Cell Counting Kit-8 (CCK-8) and 5-Bromo-2-deoxyUridine (BrDU), Ki-67 were used, and the diameter of neural spheres was measured to observe proliferation ability 48 h later. Doublecortin (DCX), glial fibrillary acidic protein (GFAP), microtubule-associated proteins 2 (MAP-2), synapsin I (SYN1), and postsynaptic density protein-95 (PSD-95) were stained to identify the effect of miR-140-5p on the differentiation ability of NSCs into neural precursor cells, astrocytes, and neurons and the expression of synapse-associated proteins. The expression of miR-140-5p, Prox1, p-ERK1/2, and ERK1/2 was analyzed by real time quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis.Results: While the expression of miR-140-5p decreased after NSC differentiation (P<0.05), the results of CCK-8, BrDU, and Ki-67 staining showed no significant difference in cell viability and the percentage of NSCs with proliferation ability (P>0.05). However, the neural spheres were shorter in the miR-140-5p overexpression group (P<0.05) and the expression of DCX, MAP2, synapsin I, and PSD-95 decreased, while the expression of GFAP increased after differentiation in the mimic group (P<0.05). In addition, the expression of Prox1 decreased and the expression of p-ERK1/2 protein increased (P<0.05), but the expression of ERK1/2 showed no significant difference (P>0.05) in the miR-140-5p overexpression group.Conclusions: MiR-140-5p reduced the proliferation rate of NSCs, inhibited their differentiation into neurons, produced synapse-associated proteins, and promoted their differentiation into astrocytes. MiR-140-5p negatively regulated downstream target Prox1 and activated the ERK/MAPK signaling pathway.

To explore the relationship between the monocyte-to-lymphocyte ratio (MLR) and depression three months after acute ischemic stroke. Patients and Methods: From May 2013 to September 2014, 203 patients with acute ischemic stroke were recruited within 7 days post-stroke from Shanghai Ruijin Hospital and blood samples were collected after admission. The Hamilton Depression Scale and Clinical Review were evaluated at 3 months after stroke. Based on the Diagnostic and Statistical Manual of Mental Disorders-IV diagnostic criteria, we divided patients into post-stroke depression (PSD) and non-PSD groups. We analyzed the intergroup difference in MLR and the contributing factors. Moreover, dynamic changes in monocytes, lymphocytes and MLR at four different time intervals for all the stroke patients and their relationship with PSD patients were also studied. Results: The NIHSS scores and MLR in the PSD group were significantly higher than in the non-PSD group (p<0.05). Logistic regression analysis revealed MLR was an independent risk factor for PSD (odds ratio: 18.020, 95% confidence interval: 1.127-288.195, p=0.041). MLR correlated negatively with cholesterol and low-density lipoprotein (r=−0.160 and −0.165, respectively, p<0.05). Within 7 days post-acute ischemic stroke, monocytes gradually increased while lymphocytes remained unchanged for all the stroke patients. The MLR value was significantly higher in the PSD group than in the non-PSD group within 24 h post-stroke (p<0.05), but there was no difference in the other three time-intervals between the two groups. Conclusion: The admission MLR, particularly within 24 h post-stroke, was associated with PSD at 3 months, implying that the MLR might be involved in the PSD inflammatory mechanism.

There are two widely used models for the Grassmannian Gr(k, n), as the set of equivalence classes of orthogonal matrices O(n)/ O(k) × O(n − k) , and as the set of trace-k projection matrices {P ∈ R n×n : P T = P = P 2 , tr(P ) = k}. The former, standard in manifold optimization, has the advantage of giving numerically stable algorithms but the disadvantage of having to work with equivalence classes of matrices. The latter, widely used in coding theory and probability, has the advantage of using actual matrices (as opposed to equivalence classes) but working with projection matrices is numerically unstable. We present an alternative that has both advantages and suffers from neither of the disadvantages; by representing k-dimensional subspaces as symmetric orthogonal matrices of trace 2k − n, we obtainAs with the other two models, we show that differential geometric objects and operations -tangent vector, metric, normal vector, exponential map, geodesic, parallel transport, gradient, Hessian, etc -have closed-form analytic expressions that are computable with standard numerical linear algebra. In the proposed model, these expressions are considerably simpler, a result of representing Gr(k, n) as a linear section of a compact matrix Lie group O(n), and can be computed with at most one qr decomposition and one exponential of a special skew-symmetric matrix that takes only O nk(n − k) time. In particular, we completely avoid eigen-and singular value decompositions in our steepest descent, conjugate gradient, quasi-Newton, and Newton methods for the Grassmannian.

Objective This study aimed to explore the correlation between white matter hyperintensity (WMH) and post-stroke depression (PSD) at 3 months, and to further investigate sex differences in the pathogenesis of PSD. Methods A total of 238 consecutive patients with acute cerebral infarction were recruited. PSD was assessed at 2 weeks and at 3 months after stroke onset. All stroke cases were divided into four subgroups according to the diagnosis of depression at two time nodes: continuous depression; depression remission; late-onset PSD; and continuous non-depression. The Fazekas and Scheltens visual rating scales were adopted to assess WMH. Results Logistic regression revealed that the presence of periventricular white matter hyperintensity (PVWMH) at baseline in male patients was an independent risk factor for PSD at 3 months. Further subgroup analysis revealed that PVWMH was associated with late-onset PSD in males, but not with continuous depression 3 months after stroke. Male acute stroke patients with PVWMH at baseline were more likely to develop PSD at 3 months, especially late-onset PSD. Conclusion Our data suggest that sex differences may influence the pathogenesis of PSD.