Exploring causal association between functional/structural connectivity and major depression disorder: A bidirectional Mendelian randomization study.

OBJECTIVES: Prior observational studies have suggested a correlation between major depressive disorder (MDD) and communication imbalances within the resting-state brain network (RSN), but the causal relationship remains unclear. This research uses Mendelian randomization (MR) analysis to explore the potential causal effects between functional connectivity (FC), structural connectivity (SC) and MDD. METHODS: Two-sample bidirectional MR analysis was employed in this study. Inverse variance weighted (IVW) was used to explore the causal relationship between the FC/SC and MDD, with various methods such as MR-Egger to conduct sensitivity analyses. RESULTS: The IVW analysis results showed that higher genetic predicted dorsal attention network FC, limbic network SC, and dorsal attention network SC were associated with an increased risk of MDD (ß: 15.08, 95%CI: 5.89-24.27, p = 0.001; ß: 3.79, 95%CI: -0.22-7.8, p = 0.034; ß: 9.89, 95%CI: 0.88-18.90, p = 0.031). Reverse MR analysis demonstrated that a genetically predicted elevated risk of MDD was associated with reduced frontal parietal network FC (ß: -0.00046, p = 0.041). CONCLUSIONS: The study suggests a causal relationship between the FC and SC within specific RSNs and the risk of MDD. Abnormalities in the dorsal attention network FC/SC and the limbic network SC were risk factors for MDD. The FC abnormality of the frontal parietal network may be the downstream influence following the MDD onset. Further investigation is needed to determine the potential utility of these neuroimaging markers in the prevention of MDD or the evaluation of treatment efficacy.

Exploring causal association between circulating inflammatory cytokines and functional outcomes following ischemic stroke: A bidirectional Mendelian randomization study.

OBJECTIVES: Previous observational studies have indicated correlations between various inflammatory cytokines and functional outcomes following ischemic stroke (IS); however, the causality remains unclear. We aimed to further evaluate the causal association between 41 circulating inflammatory cytokines and functional outcomes following IS. METHODS: Two-sample bidirectional Mendelian randomization (MR) analysis was used in this study. The genetic variation of 41 circulating inflammatory cytokines were derived from genome-wide association study (GWAS) data of European ancestry (n = 8293). The corresponding genetic association of functional outcomes following IS were derived from European ancestry GWAS data (n = 6021). RESULTS: Inverse variance weighted (IVW) analysis showed that genetically predicted increased levels of regulation and activation in normal T-cell expression and secretion factor (RANTES/CCL5) and eosinophilic chemotactic factor (EOTAXIN/CCL11) were positively correlated with the increased adverse functional outcomes (modified Rankin Scale [mRS≥3] following IS (OR: 1.40, 95% CI: 1.002-1.96, p = 0.049; OR: 1.33, 95% CI: 1.15-1.54, p = 0.0001). Interleukin 18 (IL-18) level might be the downstream consequence of adverse functional outcomes following IS (ß: -0.09, p = 0.039). Other inflammatory cytokines and functional outcomes following IS did not appear to be causally related. CONCLUSIONS: This study suggests a causality between inflammation and adverse functional outcomes following IS. RANTES (CCL5) and EOTAXIN (CCL11) may be the upstream factors of adverse functional outcomes following IS, while IL-18 may be the downstream effect of adverse functional outcomes following IS. Whether these cytokines can be used to predict or improve adverse functional outcomes after IS requires further researches.

Electroacupuncture alleviated depression-like behaviors in ventromedial prefrontal cortex of chronic unpredictable mild stress-induced rats: Increasing synaptic transmission and phosphorylating dopamine transporter.

AIMS: Electroacupuncture (EA) shows advantages in both clinical practice and depression animal models. Dopaminergic-related dysfunction in the prefrontal cortex (PFC) may be a hidden antidepressant mechanism of EA, where dopamine transporter (DAT) plays an essential role. This study aimed to investigate the synaptic transmission and DAT-related changes of EA in depression. METHODS: Male Sprague-Dawley rats were subjected to 3-week chronic unpredictable mild stress (CUMS). The successfully modeled rats were then randomly and equally assigned to CUMS, selective serotonin reuptake inhibitor (SSRI), and EA or SSRI + EA groups, followed by a 2-week treatment respectively. After monitoring body weight and behavioral tests of all rats, the ventromedial PFC (vmPFC) tissue was collected for electrophysiology and the expression detection of DAT, phosphorylated DAT (p-DAT), cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), and trace amine-associated receptor 1 (TAAR1). RESULTS: Depressive-like behaviors induced by CUMS were alleviated by EA, SSRI, and SSRI + EA treatments through behavioral tests. Compared with CUMS group, EA improved synaptic transmission in vmPFC by upregulating spontaneous excitatory postsynaptic currents amplitude. Molecularly, EA reversed the increased total DAT and p-DAT expression as well as the decreased ratio of p-DAT/total DAT along with the activation of TAAR1, cAMP, and PKA in vmPFC. CONCLUSION: We speculated that the antidepressant effect of EA was associated with enhanced synaptic transmission in vmPFC, and the upregulated phosphorylation of DAT relevant to TAAR1, cAMP, and PKA may be the potential mechanism.

Mixing regime shapes the community assembly process, microbial interaction and proliferation of cyanobacterial species Planktothrix in a stratified lake.

Lake mixing influences aquatic chemical properties and microbial community composition, and thus, we hypothesized that it would alter microbial community assembly and interaction. To clarify this issue, we explored the community assembly processes and cooccurrence networks in four seasons at two depths (epilimnion and hypolimnion) in a mesotrophic and stratified lake (Chenghai Lake), which formed stratification in the summer and turnover in the winter. During the stratification period, the epilimnion and hypolimnion went through contrary assembly processes but converged to similar assembly patterns in the mixing period. In a highly homogeneous selection environment, species with low niche breadth were filtered, resulting in decreased species richness. Water mixing in the winter homogenized the environment, resulting in a simpler microbial cooccurrence network. Interestingly, we observed a high abundance of the cyanobacterial genus Planktothrix in the winter, probably due to nutrient redistribution and Planktothrix adaptivity to the winter environment in which mixing played important roles. Our study provides deeper fundamental insights into how environmental factors influence microbial community structure through community assembly processes.

Scalp acupuncture enhances local brain regions functional activities and functional connections between cerebral hemispheres in acute ischemic stroke patients.

This study aimed to explore the changes in functional connections between cerebral hemispheres and local brain regions functional activities in patients with acute ischemic stroke (AIS) treated with International Standard Scalp Acupuncture (ISSA). Thirty patients with middle cerebral artery AIS in the dominant hemisphere were selected and randomly divided into two groups such as the control group and the scalp acupuncture group, with 15 patients in each group. Patients in the control group were treated with conventional Western medicine, while patients in the scalp acupuncture group received ISSA (acupuncture at the parietal midline [MS5], acupuncture at the left anterior parietotemporal oblique line [MS6] and acupuncture at the left posterior parietotemporal oblique line [MS7]) for one course of treatment. All patients were evaluated for treatment efficacy and received whole brain resting state functional magnetic resonance imaging (Rs-fMRI) scan before and after treatment. The observational indicators included: (a) the National Institutes of Health Stroke Scale (NIHSS) scores and the simplified Fugl-Meyer Assessment (SFMA) scores; (b) analyses of the amplitude of low-frequency fluctuation (ALFF), regional homogeneity (ReHo) and voxel-mirrored homotopic connectivity (VMHC). The results showed a significant difference in the NIHSS scores before and after treatment in the scalp acupuncture group compared with the control group (p < .05), indicating that patients improved better after scalp acupuncture treatment. Compared with the control group, the VMHC, ALFF and ReHo values in the scalp acupuncture group increased after treatment. The VMHC values increased in the brain regions dominated by bilateral BA6 and BA8; the ALFF values increased in the left BA39 and the adjacent superior temporal gyrus and middle temporal gyrus; and the ReHo values increased in the brain regions extending from left middle temporal gyrus (including BA21) to BA37, and the brain regions extending from the left BA40 and angular gyrus to BA7. The present study indicated that scalp acupuncture can specifically strengthen the functional activities of the brain regions related to sensory integration, language processing and motor coordination in the middle aged and elderly patients with AIS of the dominant cerebral hemisphere, and can strengthen bilateral frontal lobe motor control. This study may provide a scientific basis for the clinical application of ISSA treatment in patients with AIS, and may also provide a preliminary research basis for further animal experiments.

Scalp Acupuncture Enhances the Functional Connectivity of Visual and Cognitive-Motor Function Network of Patients with Acute Ischemic Stroke.

DESIGN: A parallel-group randomized controlled trial. Participants. 30 hemiplegic patients with middle cerebral artery acute infarction of the dominant hemisphere. Interventions. 30 patients were divided into 2 groups randomly. 15 patients in the treatment group (TG) were treated with ISSA, needling at the parietal midline (MS5) and left anterior/posterior parietal-temporal oblique lines (MS6 and MS7), combined with western routine treatment. While another 15 patients in the control group (CG) received routine treatment only. Main Outcome Measures. (1) Functional connectivity (FC): patients received brain scan using 3.0 T MRI after the treatment for 1 week. Based on the Matlab2012a platform, SPM12 software and DPABI software were used to process the scanning data and finally the functional connectivity of the brain was obtained. (2) National Institute of Health Stroke Scale (NIHSS) score. RESULTS: The difference in the NIHSS score between the two groups of patients before and after treatment was statistically significant (tNIHSS = 2.225; PNIHSS = 0.038), indicating that TG had a better effect. Centered to the seed region of the left supplementary motor area (SMA) (-5.32, 4.85, 61.38), FC increased at the left middle cerebellar peduncle, left cerebellum posterior lobe (uvula and declive), vermis, fusiform gyrus, lingual gyrus, inferior occipital gyrus, calcarine, cuneus, precuneus, BA7, BA18 and BA19, etc. Centered to the seed region of the left parahippocampal gyrus (PG) (-21.17, -15.95, -20.70), FC increased at the left precuneus, inside-paracingulate, inferior parietal gyrus, paracentral lobule, BA5, BA6, BA7, and BA40, right median cingulate, precuneus, BA19, BA23, and BA31, etc. CONCLUSIONS: It is indicated that ISSA can regulate the brain functional connection in patients with middle cerebral artery acute infarction in the dominant hemisphere and specifically strengthen the connections between visual, cognitive, motor control, and planning-related brain regions, which may be related to the recovery of movement in the mechanism. This trial is registered with ChiCTR-IOR-15007672.