Background Poststroke cognitive impairment (PSCI) is prevalent in stroke patients. The etiology of PSCI remains largely unknown. We previously found that stroke induces gut microbiota dysbiosis which affects brain injury. Hereby, we aimed to investigate whether the gut microbiota contributes to the pathogenesis of PSCI. Methods 83 stroke patients were recruited and their cognitive function were measured by Montreal Cognitive Assessment (MoCA) scores 3 months after stroke onset. The peripheral inflammatory factor levels and gut microbiota compositions of the patients were analyzed. Fecal microbiota transplantation from patients to stroke mice was performed to examine the causal relationship between the gut microbiota and PSCI. The cognitive function of mice was evaluated by Morris water maze test. Results 34 and 49 stroke patients were classified as PSCI and non-PSCI, respectively. Compared with non-PSCI patients, PSCI patients showed significantly higher levels of gut Enterobacteriaceae, lipopolysaccharide (LPS) and peripheral inflammation markers. Consistently, stroke mice that received microbiota from PSCI patients (PSCI mice) presented a higher level of Enterobacteriaceae, intestinal Toll-like receptor-4 (TLR4) expression, circulating LPS, LPS-binding protein (LBP) and inflammatory cytokines, and a lower level of fecal butyrate, severer intestine destruction and cognitive impairment than mice that received microbiota from nPSCI patients (nPSCI mice). In addition, we observed exacerbations in blood–brain barrier (BBB) integrity, microglial activation, neuronal apoptosis in the CA1 region of the hippocampus, and Aβ deposition in the thalamus of PSCI mice in comparison with nPSCI mice. Intraperitoneal injection of LPS after stroke caused similar pathology to those seen in PSCI mice. Supplementation with sodium butyrate (NaB) via drinking water rescued these detrimental changes in PSCI mice. Conclusions Our data indicate a cause–effect relationship between gut microbiota and PSCI for the first time, which is likely mediated by inflammation-regulating metabolites including LPS and butyrate.
Background and PurposeIdentifying risks of stroke-associated pneumonia (SAP) is important for clinical management. We aimed to evaluate the association between gut microbiome composition and SAP in patients with acute ischemic stroke (AIS).MethodsA prospective observational study was conducted, and 188 AIS patients were enrolled as the training cohort. Fecal and serum samples were collected at admission. SAP was diagnosed by specialized physicians, and disease severity scores were recorded. Fecal samples were subjected to 16S rRNA V4 tag sequencing and analysed with QIIME and LEfSe. Associations between the most relevant taxa and SAP were analysed and validated with an independent cohort. Fecal short-chain fatty acid (SCFA), serum D-lactate (D-LA), intestinal fatty acid-binding protein (iFABP) and lipopolysaccharide binding protein (LBP) levels were measured.ResultsOverall, 52 patients (27.7%) had SAP in the training cohort. The gut microbiome differed between SAP and non-SAP patients; specifically, Roseburia depletion and opportunistic pathogen enrichment were noted in SAP patients, as confirmed in the validation cohort (n=144, 28 SAP [19.4%]). Based on multivariate analysis, Roseburia was identified as a protective factor against SAP in both cohorts (training, aOR 0.52; 95% CI, 0.30-0.90; validation, aOR 0.44; 95% CI, 0.23-0.85). The combination of these taxa into a microbial dysbiosis index (MDI) revealed that dysbiosis increased nearly 2 times risk of SAP (training, aOR 1.95; 95% CI, 1.19-3.20; validation, aOR 2.22; 95% CI, 1.15-4.26). Lower fecal SCFA levels and higher serum D-LA levels were observed in SAP patients. Furthermore, SAP was an independent risk factor of 30-day death and 90-day unfavorable outcome.ConclusionWe demonstrate that a microbial community with depleted Roseburia and enriched opportunistic pathogens is associated with increased risk of SAP among AIS patients. Gut microbiota screening might be useful for identifying patients at high risk for SAP and provide clues for stroke treatment.
Screened bonding (SB), screened antibonding (SA) and charge transfer plasmon (CTP) modes in the conductively connected nanorod heterodimer are studied in detail by simulation. All of the SB, SA and CTP modes can be observed in the extinction spectra of the conductively connected nanorod heterodimer. Also, the amplitudes of the three modes can be tuned by changing the radius of the cylinder conductive connection. Even the amplitude of the SA mode can be tuned to be higher than that of the SB mode, which is difficult to achieve in an unconnected nanorod heterodimer. Furthermore, the wavelengths of the three plasmon modes can be adjusted with a high degree of freedom, since the wavelength of the SB mode mainly depends on the length of the longer nanorod, the wavelength of the SA mode mainly depends on the length of the shorter nanorod and the wavelength of the CTP mode mainly depends on the total length of the nanorod heterodimer. Our study will be helpful for the design of plasmon enhancement devices, such as surface enhanced Raman scattering (SERS), plasmon enhanced fluorescence, plasmon rulers and so on.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.