The Influence of Gut Dysbiosis in the Pathogenesis and Management of Ischemic Stroke

Analysis of the brain transcriptome, microbiome and metabolome in ketogenic diet and experimental stroke

The ketogenic diet (KD) has been shown to be effective in treating various brain pathologies. In this study, we conducted detailed transcriptomic and metabolomic profiling of rat brains after KD and ischemic stroke in order to investigate the effects of KD and its underlying mechanisms. We evaluated the effect of a two-month KD on gene expression in intact brain tissue and after middle cerebral artery occlusion (MCAO). We analyzed the effects of KD on gut microbiome composition and blood metabolic profile as well as investigated the correlation between severity of neurological deficits and KD-induced changes. We found transcriptional reprogramming in the brain after stroke and KD treatment. The KD altered the expression of genes involved in the regulation of glucose and fatty acid metabolism, mitochondrial function, the immune response, Wnt-associated signaling, stem cell development, and neurotransmission, both in intact rats and after MCAO. The KD led to a significant change in the composition of gut microbiome and the levels of amino acids, acylcarnitines, polyunsaturated fatty acids, and oxylipins in the blood. However, the KD slightly worsened the neurological functions after MCAO, so that the therapeutic effect of the diet remained unproven.

Valorizing Agro‐Food Waste for Nutraceutical Development: Sustainable Approaches for Managing Metabolic Dysfunction‐Associated Steatotic Liver Disease and Related Co‐Morbidities

This comprehensive investigation delves into the interconnectedness of different features of cardiometabolic syndrome, such as metabolic dysfunction‐associated steatotic liver disease (MASLD), atherosclerotic cardiovascular disease (ASCVD), and gut dysbiosis, highlighting the crucial role of nutraceuticals in their management and prevention. Given the significant overlap in the pathophysiology of these conditions, the treatment with nutraceuticals, especially those derived from agro‐food waste, offers a promising, sustainable, and innovative approach to healthcare. The 2030 Agenda for Sustainable Development and the One Health concept are key frameworks for selecting the most interesting supply chain for the production of nutraceuticals from agro‐food waste, ensuring environmental sustainability, and innovative agricultural practices. In this review, the therapeutic potential of kiwifruit and apples has been explored, detailing how their bioactive compounds, like polyphenols, fiber, pectin, kaempferol, phloretin, and phlorizin, may contribute to the management of MASLD, ASCVD, and gut dysbiosis. Various extraction methods for active ingredients, including chemical, water, and enzyme extractions, are analyzed for their respective benefits and drawbacks. By integrating scientific research, sustainable agricultural practices, and innovative extraction methods, we can develop effective strategies to combat these pervasive health issues. This holistic approach not only enhances individual health outcomes but also supports broader environmental and societal goals, promoting a healthier future for all.

Adiposity and inflammation markers explain mostly part of the plasma zonulin variation in Brazilian adults with overweight/obesity: A cross-sectional analysis from Brazilian nuts study

OBJECTIVE

This study evaluated intestinal permeability according to plasma zonulin and its association with adiposity, inflammation, cardiometabolic risk, liver function, and intestinal health markers in adults with overweight/obesity.

METHODOLOGY

This study is a cross-sectional analysis using baseline data from the Brazilian Nut Study, which involved 123 participants (93 women, age 33.2 ± 8.58 years, BMI 33.9 ± 4.30kg/m2). Subjects were divided into quartiles according to plasma zonulin, assessed by Elisa. Cytokines were assessed by flow cytometry; anthropometric measurements were collected by standard procedure and body composition was assessed by DXA. SCFA analysis was performed by high-performance liquid chromatography, and fecal pH, by a pH meter. Linear regression models were performed (α<5 %).

RESULTS

Participants included in the last quartile of plasma zonulin had higher values of body fat (%), pro-inflammatory cytokines (CRP, IL-1). According to the multivariate regression model, each one-unit increased in body fat, CRP, IL-12p70, IL-6 and IL-8 resulted correspondingly in an increment of 0.42, 0.14, 0.192, 0.250 and 0.312 ng/ml in plasma zonulin, respectively. Conversely, a one-unit decreased in IL-10 led to an increase of 0.40 ng/ml in plasma zonulin.

CONCLUSION

Intestinal permeability assessed by plasma zonulin is associated with adiposity, subclinical inflammation and reduced serum HDL levels adults with overweight/obesity, while adiposity and inflammation markers are independent factors for plasma zonulin variation.

Gut Microbiota, Bacterial Translocation, and Stroke: Current Knowledge and Future Directions

Stroke is one of the most devastating pathologies in terms of mortality, cause of dementia, major adult disability, and socioeconomic burden worldwide. Despite its severity, treatment options remain limited, with no pharmacological therapies available for hemorrhagic stroke (HS) and only fibrinolytic therapy or mechanical thrombectomy for ischemic stroke (IS). In the pathophysiology of stroke, after the acute phase, many patients develop systemic immunosuppression, which, combined with neurological dysfunction and hospital management, leads to the onset of stroke-associated infections (SAIs). These infections worsen prognosis and increase mortality. Recent evidence, particularly from experimental studies, has highlighted alterations in the microbiota-gut-brain axis (MGBA) following stroke, which ultimately disrupts the gut flora and increases intestinal permeability. These changes can result in bacterial translocation (BT) from the gut to sterile organs, further contributing to the development of SAIs. Given the novelty and significance of these processes, especially the role of BT in the development of SAIs, this review summarizes the latest advances in understanding these phenomena and discusses potential therapeutic strategies to mitigate them, ultimately reducing post-stroke complications and improving treatment outcomes.

Gut microbiota and Alzheimer's disease: Exploring natural product intervention and the Gut-Brain axis for therapeutic strategies

Numerous studies conducted over the last ten years have shown a strong correlation between the gut microbiota and the onset and progression of Alzheimer's disease (AD). However, the exact underlying mechanism is still unknown. An ongoing communication mechanism linking the gut and the brain is highlighted by the term "microbiota-gut-brain axis," which was originally coined the "gut-brain axis." Key metabolic, endocrine, neurological, and immunological mechanisms are involved in the microbiota‒gut‒brain axis and are essential for preserving brain homeostasis. Thus, the main emphasis of this review is how the gut microbiota contributes to the development of AD and how various natural products intervene in this disease. The first part of the review provides an outline of various pathways and relationships between the brain and gut microbiota, and the second part provides various mechanisms involved in the gut microbiota and AD. Finally, this review provides knowledge about natural products and their effectiveness in treating gut microbiota-induced AD. AD may be treated in the future by altering the gut microbiota with a customized diet, probiotics/prebiotics, plant products, and natural products. This entails altering the microbiological partners and products (such as amyloid protein) that these partners generate.

The Role of Gut Microbiota in Blood-Brain Barrier Disruption after Stroke

Growing evidence has proved that alterations in the gut microbiota have been linked to neurological disorders including stroke. Structural and functional disruption of the blood-brain barrier (BBB) is observed after stroke. In this context, there is pioneering evidence supporting that gut microbiota may be involved in the pathogenesis of stroke by regulating the BBB function. However, only a few experimental studies have been performed on stroke models to observe the BBB by altering the structure of gut microbiota, which warrant further exploration. Therefore, in order to provide a novel mechanism for stroke and highlight new insights into BBB modification as a stroke intervention, this review summarizes existing evidence of the relationship between gut microbiota and BBB integrity and discusses the mechanisms of gut microbiota on BBB dysfunction and its role in stroke.

Multiple omics reveal link between the microbiota-gut-brain axis and intracranial aneurysm rupture

Intracranial aneurysms (IAs) are benign cerebrovascular maladies characterized by wall dilatation in the intracranial arteries. Nevertheless, spontaneous aneurysmal rupture can cause a life-threatening spontaneous subarachnoid hemorrhage (SAH). Emerging evidence indicates potential associations between gut dysbiosis and IAs pathogenesis, though the relationship with IA rupture remains unclear. This research analyzed 124 fecal samples for microbiomics and 160 for metabolomics, with the discovery and validation sets established for cross-validation. We identified differential gut microbiota and metabolites associated with ruptured intracranial aneurysms (RIAs) and developed a superior risk assessment model. Subsequent integrative analyses and validation revealed a significant link between disrupted unsaturated fatty acid and essential amino acid metabolic pathways and IA rupture, driven by alterations in gut microbiota. This study underscores the potential association between the gut-brain axis and IA rupture, while also highlighting gut microbiota dysbiosis as a potential risk factor for IA rupture and providing biomarkers for assessment.

Periodontal bacteria influence systemic diseases through the gut microbiota

Many systemic diseases, including Alzheimer disease (AD), diabetes mellitus (DM) and cardiovascular disease, are associated with microbiota dysbiosis. The oral and intestinal microbiota are directly connected anatomically, and communicate with each other through the oral-gut microbiome axis to establish and maintain host microbial homeostasis. In addition to directly, periodontal bacteria may also be indirectly involved in the regulation of systemic health and disease through the disturbed gut. This paper provides evidence for the role of periodontal bacteria in systemic diseases via the oral-gut axis and the far-reaching implications of maintaining periodontal health in reducing the risk of many intestinal and parenteral diseases. This may provide insight into the underlying pathogenesis of many systemic diseases and the search for new preventive and therapeutic strategies.

The gut microbiome and serum metabolome are altered and interrelated in patients with intracranial atherosclerotic stenosis

OBJECTIVES

To evaluate the relationship among the gut microbiome, serum metabolites and the Intracranial atherosclerosis stenosis.

MATERIALS AND METHODS

Integrated analysis of 16S rDNA sequencing of fecal samples and untargeted serum metabolomics was applied to identify alterations in the gut microbiome and serum metabolome in 29 Intracranial atherosclerosis stenosis patients and 29 healthy control individuals.

RESULTS

Compared to healthy control individuals, the abundances of forty-five genera and one hundred seventy-seven metabolites were significantly altered in Intracranial atherosclerosis stenosis patients. At the species level, the Intracranial atherosclerosis stenosis group exhibited higher abundances of Bacteroidetes and lower abundances of Megaphaera and Muribacoccaceae. Microbial functional prediction analysis revealed enhanced activity of bacterial chemotaxis and oxidative phosphorylation within the Intracranial atherosclerosis stenosis group. In terms of metabolomic findings, the levels of dulcitol were significantly increased in the Intracranial atherosclerosis stenosis group. The levels of specific metabolites within the phosphatidylcholine and lysophosphatidylcholine families, such as PC (14:0e/24:4) and LPC 20:5, were increased, while the levels of certain other specific metabolites were decreased. Dysregulation of certain pathways, such as unsaturated fatty acid metabolism, arginine and proline metabolism may be involved in the development of Intracranial atherosclerosis stenosis. Correlation analysis of the gut microbiome and metabolites revealed a positive correlation between Bacteroides and multiple metabolites, such as Acar 12:3 and PC (8:0/22:6).

CONCLUSIONS

Our analysis revealed that Bacteroides is a key bacterial genus in gut dysbiosis and may be related to the development of Intracranial atherosclerosis stenosis.

Bioinformatics Approach to Identify the Pathogenetic Link of Gut Microbiota-Derived Short-Chain Fatty Acids and Ischemic Stroke

Stroke is a life-threatening condition that impairs the arteries and causes neurological impairment. The incidence of stroke is increasing year by year with the arrival of the aging population. Thus, there is an urgent need for early stroke diagnosis. Short-chain fatty acids (SCFAs) can modulate the central nervous system and directly and indirectly impact behavioral and cognitive functions. This study aimed to investigate the connection between SCFA metabolism and stroke development via bioinformatic analysis. Initially, the Gene Set Enrichment Analysis (GSEA) and immune cell infiltration analysis were performed based on RNA data from stroke patients to comprehend the mechanisms governing stroke pathogenesis. The functional analysis, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Protein-Protein Interaction (PPI), was performed based on the Differentially Expressed Gene (DEG) selected by the limma package. 1220 SCFA metabolism-related genes screened from Genecards databases were intersected with 242 genes in main modules determined by Weighted Gene Co-Expression Network Analysis (WGCNA), and the final 10 SCFA key genes were obtained. GO analysis revealed that these genes were involved in immune response processes. Through lasso regression analyses, we established a stroke early diagnosis model and selected 6 genes with diagnostic value. The genes were validated by the area under curve (AUC) values and had a relatively good diagnostic performance. Finally, 4 potential therapeutic drugs targeting these genes were predicted using the Drug Signatures Database (DSigDB) via Enrichr. In conclusion, this paper analyzes the involvement of SCFAs in the complex gut-brain axis mechanism, which contributes to developing new targets for treating central nervous system diseases and provides new ideas for early ischemic stroke diagnosis.

Elevated lipopolysaccharide level is largely driven by time since symptom onset in acute ischemic stroke: the impact on clinical outcomes

BACKGROUND

Gut dysbiosis leading to increased intestinal barrier permeability and translocation of lipopolysaccharide (LPS) in the circulation has been demonstrated in patients with acute myocardial infarction and pulmonary embolism.

OBJECTIVES

We investigated changes in circulating LPS concentrations in acute ischemic stroke (AIS) and their consequences, including prognosis.

METHODS

We studied 98 AIS patients, aged 74 ± 12 years, including 74 (75.5%) thrombolysed individuals. We determined serum LPS and zonulin, a marker of gut permeability, along with protein carbonyl (PC), fibrin clot properties, and thrombin generation on admission, at 24 hours and 3 months. Stroke severity was assessed using the National Institutes of Health Stroke Scale. Stroke functional outcome using modified Rankin scale and stroke-related mortality were evaluated at 3 months.

RESULTS

Serum LPS and zonulin levels on admission were associated with time since symptom onset (r = 0.57; P < .0001; and r = 0.40; P < .0001). Baseline LPS levels correlated with PC (r = 0.51; P < .0001) but not with coagulation and fibrinolysis markers. LPS levels increased at 24 hours in thrombolysed patients (P < .001) and correlated with the National Institutes of Health Stroke Scale score (r = 0.31; P = .002) and PC (r = 0.32; P = .0057). Both LPS and zonulin levels measured at 24 hours increased the odds of having unfavorable modified Rankin scale scores (odds ratio [OR], 1.22; 95% CI, 1.04-1.42; and OR, 2.36; 95% CI, 1.24-4.49 per unit). Elevated LPS level, but not zonulin, was associated with stroke-related mortality (OR, 1.26; 95% CI, 1.02-1.55 per unit).

CONCLUSION

In AIS patients intestinal permeability is mainly driven by increasing time since the symptom onset. Our findings suggest that LPS, with a trend toward its further rise following thrombolysis, adversely affects neurologic functional outcomes and 3-month mortality.

Neuronutrition and Its Impact on Post-Stroke Neurorehabilitation: Modulating Plasticity Through Diet

The recovery of neurological deficits after ischemic stroke largely depends on the brain's ability to reorganize its undamaged neuronal circuits and neuronal plasticity phenomena. The consolidated evidence highlights the involvement of the patient's impaired nutritional conditions in post-stroke recovery and unsatisfying rehabilitative outcomes. Standardized nutritional protocols usually applied in hospitalized patients in a rehabilitation setting aim mainly to improve the general health conditions of patients, do not consider the high inter-individual variability in neurorehabilitation outcomes, and are not sufficiently modifiable to provide neuroprotective and restorative dietary patterns that could promote neuronal plasticity and functional recovery during neurorehabilitation. Neuronutrition, an emergent scientific field of neuroscience, represents a valid model of a personalized nutritional approach, assuring, for each patient, nutrients having antioxidant and anti-inflammatory properties, ensuring a balanced microbiota composition, and providing adequate neurotrophic support, essential for improving neuronal plasticity, brain functional recovery, and rehabilitative outcomes. In the present narrative review, we provide an overview of the current knowledge on neuronutrition as an adjuvant strategy of a personalized nutritional approach potentially effective in improving post-stroke neuroplasticity and neurorehabilitation by counteracting or at least limiting post-stroke oxidative/nitrosative stress, neuroinflammation, and gut-brain axis disturbance.

Magnesium-L-threonate treats Alzheimer's disease by modulating the microbiota-gut-brain axis

JOURNAL/nrgr/04.03/01300535-202410000-00029/figure1/v/2024-02-06T055622Z/r/image-tiff Disturbances in the microbiota-gut-brain axis may contribute to the development of Alzheimer's disease. Magnesium-L-threonate has recently been found to have protective effects on learning and memory in aged and Alzheimer's disease model mice. However, the effects of magnesium-L-threonate on the gut microbiota in Alzheimer's disease remain unknown. Previously, we reported that magnesium-L-threonate treatment improved cognition and reduced oxidative stress and inflammation in a double-transgenic line of Alzheimer's disease model mice expressing the amyloid-β precursor protein and mutant human presenilin 1 (APP/PS1). Here, we performed 16S rRNA amplicon sequencing and liquid chromatography-mass spectrometry to analyze changes in the microbiome and serum metabolome following magnesium-L-threonate exposure in a similar mouse model. Magnesium-L-threonate modulated the abundance of three genera in the gut microbiota, decreasing Allobaculum and increasing Bifidobacterium and Turicibacter. We also found that differential metabolites in the magnesium-L-threonate-regulated serum were enriched in various pathways associated with neurodegenerative diseases. The western blotting detection on intestinal tight junction proteins (zona occludens 1, occludin, and claudin-5) showed that magnesium-L-threonate repaired the intestinal barrier dysfunction of APP/PS1 mice. These findings suggest that magnesium-L-threonate may reduce the clinical manifestations of Alzheimer's disease through the microbiota-gut-brain axis in model mice, providing an experimental basis for the clinical treatment of Alzheimer's disease.

Unraveling the gut-brain axis: the impact of steroid hormones and nutrition on Parkinson's disease

This comprehensive review explores the intricate relationship between nutrition, the gut microbiome, steroid hormones, and Parkinson's disease within the context of the gut-brain axis. The gut-brain axis plays a pivotal role in neurodegenerative diseases like Parkinson's disease, encompassing diverse components such as the gut microbiota, immune system, metabolism, and neural pathways. The gut microbiome, profoundly influenced by dietary factors, emerges as a key player. Nutrition during the first 1000 days of life shapes the gut microbiota composition, influencing immune responses and impacting both child development and adult health. High-fat, high-sugar diets can disrupt this delicate balance, contributing to inflammation and immune dysfunction. Exploring nutritional strategies, the Mediterranean diet's anti-inflammatory and antioxidant properties show promise in reducing Parkinson's disease risk. Microbiome-targeted dietary approaches and the ketogenic diet hold the potential in improving brain disorders. Beyond nutrition, emerging research uncovers potential interactions between steroid hormones, nutrition, and Parkinson's disease. Progesterone, with its anti-inflammatory properties and presence in the nervous system, offers a novel option for Parkinson's disease therapy. Its ability to enhance neuroprotection within the enteric nervous system presents exciting prospects. The review addresses the hypothesis that α-synuclein aggregates originate from the gut and may enter the brain via the vagus nerve. Gastrointestinal symptoms preceding motor symptoms support this hypothesis. Dysfunctional gut-brain signaling during gut dysbiosis contributes to inflammation and neurotransmitter imbalances, emphasizing the potential of microbiota-based interventions. In summary, this review uncovers the complex web of interactions between nutrition, the gut microbiome, steroid hormones, and Parkinson's disease within the gut-brain axis framework. Understanding these connections not only offers novel therapeutic insights but also illuminates the origins of neurodegenerative diseases such as Parkinson's disease.

Short-chain fatty acid on blood-brain barrier and glial function in ischemic stroke

Stroke is the second most common cause of death and one of the most common causes of disability worldwide. The intestine is home to several microorganisms that fulfill essential functions for the natural and physiological functioning of the human body. There is an interaction between the central nervous system (CNS) and the gastrointestinal system that enables bidirectional communication between them, the so-called gut-brain axis. Based on the gut-brain axis, there is evidence of a link between the gut microbiota and the regulation of microglial functions through glial activation. This interaction is partly due to the immunological properties of the microbiota and its connection with the CNS, such that metabolites produced by the microbiota can cross the gut barrier, enter the bloodstream and reach the CNS and significantly affect microglia, astrocytes and other cells of the immune system. Studies addressing the effects of short-chain fatty acids (SCFAs) on glial function and the BBB in ischemic stroke are still scarce. Therefore, this review aims to stimulate the investigation of these associations, as well as to generate new studies on this topic that can clarify the role of SCFAs after stroke in a more robust manner.

Electroacupuncture Promotes the Generation of Intestinal Treg Cells After Ischemic Stroke by Foxp3 Acetylation Regulation

Electroacupuncture (EA) has been shown to ameliorate brain injury and protect against intestinal injury after ischemic stroke. These protective effects are closely associated with the enhancement of regulatory T (Treg) cell numbers and function in the intestine, as well as the inhibition of intestinal γδ T cell production and their migration to the brain. This study aimed to elucidate the potential mechanism by which EA regulates intestinal Treg cell differentiation after stroke. Sprague-Dawley rats were divided into three groups: the sham group, the middle cerebral artery occlusion (MCAO) group, and the MCAO plus EA (MEA) group. The MCAO model was generated by occluding the middle cerebral artery. EA was applied to Baihui (GV20) acupoint once daily. Samples were collected 3 days after reperfusion. Our results showed that EA reduced the inflammatory response in the brain and intestine after ischemic stroke. EA treatment increased the percentage of Treg cells in the small intestine of rats. EA increased the levels of SCFAs, while also inhibiting histone deacetylase activity (HDAC). Additionally, acetylated Foxp3 protein in the small intestine was increased after EA treatment. These results suggest that EA at GV20 alleviates brain and intestinal inflammatory injury in stroke rats, potentially through the enhancement of SCFA-mediated Foxp3 acetylation in Treg cells.

Buqi-Huoxue-Tongnao decoction drives gut microbiota-derived indole lactic acid to attenuate ischemic stroke via the gut-brain axis

BACKGROUND

Ischemic stroke belongs to "apoplexy" and its pathogenesis is characterized by qi deficiency and blood stasis combining with phlegm-damp clouding orifices. Buqi-Huoxue-Tongnao decoction (BHTD) is a traditional Chinese medicine formula for qi deficiency, blood stasis and phlegm obstruction syndrome. However, its efficacy and potential mechanism on ischemic stroke are still unclear. This study aims to investigate the protective effect and potential mechanism of BHTD against ischemic stroke.

MATERIALS AND METHODS

Middle cerebral artery occlusion (MCAO) surgery was carried out to establish an ischemic stroke model in rats. Subsequently, the rats were gavaged with different doses of BHTD (2.59, 5.175, 10.35 g/kg) for 14 days. The protective effects of BHTD on the brain and gut were evaluated by neurological function scores, cerebral infarction area, levels of brain injury markers (S-100B, NGB), indicators of gut permeability (FD-4) and bacterial translocation (DAO, LPS, D-lactate), and tight junction proteins (Occludin, Claudin-1, ZO-1) in brain and colon. 16S rRNA gene sequencing and metabolomic analysis were utilized to analyze the effects on gut microecology and screen for marker metabolites to explore potential mechanisms of BHTD protection against ischemic stroke.

RESULTS

BHTD could effectively mitigate brain impairment, including reducing neurological damage, decreasing cerebral infarction and repairing the blood-brain barrier, and BHTD showed the best effect at the dose of 10.35 g/kg. Moreover, BHTD reversed gut injury induced by ischemic stroke, as evidenced by decreased intestinal permeability, reduced intestinal bacterial translocation, and enhanced intestinal barrier integrity. In addition, BHTD rescued gut microbiota dysbiosis by increasing the abundance of beneficial bacteria, including Turicibacter and Faecalibaculum. Transplantation of the gut microbiota remodeled by BHTD into ischemic stroke rats recapitulated the protective effects of BHTD. Especially, BHTD upregulated tryptophan metabolism, which promoted gut microbiota to produce more indole lactic acid (ILA). Notably, supplementation with ILA by gavage could alleviate stroke injury, which suggested that driving the production of ILA in the gut might be a novel treatment for ischemic stroke.

CONCLUSION

BHTD could increase gut microbiota-derived indole lactic acid to attenuate ischemic stroke via the gut-brain axis. Our current finding provides evidence that traditional Chinese medicine can ameliorate central diseases through regulating the gut microbiology.

Blueberry extract for the treatment of ischaemic stroke through regulating the gut microbiota and kynurenine metabolism

Although the gut microbiota and kynurenine (KYN) metabolism have significant protective effects against ischaemic stroke (IS), the exact mechanism has yet to be fully elucidated. Combined serum metabolomics and 16S rRNA gene sequencing were used to reveal the differences between the gut microbiota and metabolites in rats treated with or without blueberry extract. Faecal microbiota transplantation (FMT) was employed to validate the protective role of the gut microbiota in IS. Furthermore, the interaction between Prevotella and IS was also confirmed in patients. Rats with IS experienced neurological impairments accompanied by an impaired intestinal barrier and disturbed intestinal flora, which further contributed to heightened inflammatory responses. Furthermore, Prevotella played a critical role in IS pathophysiology, and a positive correlation between Prevotella and KYN was detected. The role of KYN metabolism in IS was further demonstrated by the finding that IDO was significantly upregulated and that the use of the IDO inhibitor, attenuated KYN metabolic pathway activity and ameliorated neurological damage in rats with IS. Prevotella intervention also significantly improved stroke symptoms and decreasing KYN levels in rats with IS. FMT showed that the beneficial effects of blueberry extract on IS involve gut bacteria, especially Prevotella, which were confirmed by microbiological analyses conducted on IS patients. Moreover, blueberry extract led to significant changes in kynurenic acid levels and tryptophan and IDO levels through interactions with Prevotella. Our study demonstrates for the first time that blueberry extract could modulate "intestinal microecology-KYN metabolism" to improve IS.

Neuromicrobiology Comes of Age: The Multifaceted Interactions between the Microbiome and the Nervous System

The past decade has seen an explosion in our knowledge about the interactions between gut microbiota, the central nervous system, and the immune system. The gut-brain axis has recently gained much attention due to its role in regulating host physiology. This review explores recent findings concerning potential pathways linking the gut-brain axis to the initiation, pathophysiology, and development of neurological disorders. Our objective of this work is to uncover causative factors and pinpoint particular pathways and therapeutic targets that may facilitate the translation of experimental animal research into practical applications for human patients. We highlight three distinct yet interrelated mechanisms: (1) disruptions of both the intestinal and blood-brain barriers, (2) persistent neuroinflammation, and (3) the role of the vagus nerve.

Multistrain Probiotics with Fructooligosaccharides Improve Middle Cerebral Artery Occlusion-Driven Neurological Deficits by Revamping Microbiota-Gut-Brain Axis

Recent burgeoning literature unveils the importance of gut microbiota in the neuropathology of post-stroke brain injury and recovery. Indeed, ingestion of prebiotics/probiotics imparts positive effects on post-stroke brain injury, neuroinflammation, gut dysbiosis, and intestinal integrity. However, information on the disease-specific preference of selective prebiotics/probiotics/synbiotics and their underlying mechanism is yet elusive. Herein, we examined the effect of a new synbiotic formulation containing multistrain probiotics (Lactobacillus reuteri UBLRu-87, Lactobacillus plantarum UBLP-40, Lactobacillus rhamnosus UBLR-58, Lactobacillus salivarius UBLS-22, and Bifidobacterium breve UBBr-01), and prebiotic fructooligosaccharides using a middle cerebral artery occlusion (MCAO) model of cerebral ischemia in female and male rats. Three weeks pre-MCAO administration of synbiotic rescinded the MCAO-induced sensorimotor and motor deficits on day 3 post-stroke in rotarod, foot-fault, adhesive removal, and paw whisker test. We also observed a decrease in infarct volume and neuronal death in the ipsilateral hemisphere of synbiotic-treated MCAO rats. The synbiotic treatment also reversed the elevated levels/mRNA expression of the glial fibrillary acidic protein (GFAP), NeuN, IL-1β, TNF-α, IL-6, matrix metalloproteinase-9, and caspase-3 and decreased levels of occludin and zonula occludens-1 in MCAO rats. 16S rRNA gene-sequencing data of intestinal contents indicated an increase in genus/species of Prevotella (Prevotella copri), Lactobacillus (Lactobacillus reuteri), Roseburia, Allobaculum, and Faecalibacterium prausnitzii, and decreased abundance of Helicobacter, Desulfovibrio, and Akkermansia (Akkermansia muciniphila) in synbiotic-treated rats compared to the MCAO surgery group. These findings confer the potential benefits of our novel synbiotic preparation for MCAO-induced neurological dysfunctions by reshaping the gut-brain-axis mediators in rats.

Research progress and challenges of stem cell therapy for ischemic stroke

Ischemic stroke is a significant global cause of death and disability. Currently, treatment options for acute ischemic stroke are limited to intravenous thrombolysis and mechanical recanalization. Therefore, novel neuroprotective strategies are imperative. Stem cell transplantation possesses the capabilities of differentiation, proliferation, neuronal replacement, nerve pathway reconstruction, secretion of nerve growth factors, and enhancement of the microenvironment; thus, it is a potential therapeutic approach for ischemic stroke. In addition, the immunomodulatory function of stem cells and the combined treatment of stem cells and exosomes exhibit a favorable protective effect on brain injury and neurological dysfunction following stroke. Meanwhile, the theory of microbiota-gut-brain axis provides us with a novel perspective for comprehending and managing neurological diseases. Lastly, stem cell transplantation has demonstrated promising outcomes not only in treating ischemic stroke but also in dealing with other neurological disorders, such as brain tumors. Furthermore, challenges related to the tissue source, delivery method, immune response, and timing of transplantation still need to be addressed to optimize the treatment.

Exploring the gut microbiome-Postoperative Cognitive Dysfunction connection: Mechanisms, clinical implications, and future directions

Postoperative Cognitive Dysfunction (POCD) is a common yet poorly understood complication of surgery that can lead to long-term cognitive decline. The gut-brain axis, a bidirectional communication system between the central nervous system and the gut microbiota, plays a significant role in maintaining cognitive health. The potential for anesthetic agents and perioperative medications to modulate the gut microbiota and influence the trajectory of POCD suggests the need for a more integrated approach in perioperative care. Perioperative medications, including opioids and antibiotics, further compound these disruptions, leading to dysbiosis and consequent systemic and neuroinflammation implicated in cognitive impairment. Understanding how surgical interventions and associated treatments affect this relationship is crucial for developing strategies to reduce the incidence of POCD. Strategies to preserve and promote a healthy gut microbiome may mitigate the risk and severity of POCD. Future research should aim to clarify the mechanisms linking gut flora alterations to cognitive outcomes and explore targeted interventions, such as probiotic supplementation and microbiota-friendly prescription practices, to safeguard cognitive function postoperatively.

Stroke and Distal Organ Damage: Exploring Brain-Kidney Crosstalk

Stroke and kidney dysfunction represent significant public health challenges, yet the precise mechanisms connecting these conditions and their severe consequences remain unclear. Individuals experiencing chronic kidney disease (CKD) and acute kidney injury (AKI) are at heightened susceptibility to experiencing repeated strokes. Similarly, a reduced glomerular filtration rate is associated with an elevated risk of suffering a stroke. Prior strokes independently contribute to mortality, end-stage kidney disease, and cardiovascular complications, underscoring the pathological connection between the brain and the kidneys. In cases of AKI, various mechanisms, such as cytokine signaling, leukocyte infiltration, and oxidative stress, establish communication between the brain and the kidneys. The bidirectional relationship between stroke and kidney pathologies involves key factors such as uremic toxins, proteinuria, inflammatory responses, decreased glomerular filtration, impairment of the blood-brain barrier (BBB), oxidative stress, and metabolites produced by the gut microbiota. This review examines potential mechanisms of brain-kidney crosstalk underlying stroke and kidney diseases. It holds significance for comprehending multi-organ dysfunction associated with stroke and for formulating therapeutic strategies to address stroke-induced kidney dysfunction and the bidirectional pathological connection between the kidney and stroke.

Study on the correlation between serum indole-3-propionic acid levels and the progression and prognosis of acute ischemic stroke

OBJECTIVE

This study aimed to explore the correlation between the serum level of indole-3-propionic acid (IPA) and the progression and prognosis of acute cerebral infarction (ACI).

METHODS

This study enrolled 197 patients with ACI, and 53 participants from a community-based stroke screening program during the same period were included as the control group. The patients with ACI were divided into quartiles of serum IPA. A logistic regression model was used for comparison. Receiver operating characteristic (ROC) curves were drawn to evaluate the predictive value of the IPA.

RESULTS

Compared with the healthy control group, the ACI group had lower serum IPA (P < 0.05). The serum IPA was an independent factor for acute ischemic stroke (OR=0.992, 95% CI: 0.984-0.999, P=0.035). The serum IPA was lower in patients with progressive stroke or poor prognosis than in patients with stable stroke or good prognosis (P < 0.05). Patients with ACI with low serum IPA are prone to progression and poor prognosis. The best cutoff value for predicting progression was 193.62 pg/mL (sensitivity, 67.5%; specificity 83.7%), and that for poor prognosis was 193.77 pg/mL (sensitivity, 71.1%; specificity, 72.5%).

CONCLUSION

The serum level of IPA was an independent predictor of ACI and had certain clinical value for predicting stroke progression and prognosis in patients with ACI.

Network analysis of microbiome and metabolome to explore the mechanism of raw rhubarb in the protection against ischemic stroke via microbiota-gut-brain axis

Ischemic stroke (IS) has attracted worldwide attention due to the high mortality and disability rate. Raw rhubarb (RR) is a traditional medicinal plant and whole-food that has been used in China for its various pharmacological activities, such as antioxidant and anti-inflammatory properties. Recent pharmacological research has shown the role of RR against IS, but its mechanism of action remains unclear, particularly in the context of the brain-gut axis. To address this gap in knowledge, the present study was conducted in the middle cerebral artery occlusion/reperfusion (MCAO/R) model with the aim of investigating the effects of RR on regulating the intestinal microbiota barrier and metabolism and thereby reducing inflammatory response so as to improve the IS. The results showed that pre-treatment of RR attenuated cerebral infarct area and inflammation response in MCAO rats. Furthermore, RR also improved intestinal barrier function, including the integrity and permeability of the intestinal barrier. Additionally, RR intervention significantly attenuated gut microbiota dysbiosis caused by ischemic stroke, especially the increased Firmicutes. Notably, the pseudo-germ-free (PGF) rats further demonstrated that the anti-stroke effect of RR might rely on intestinal microbiota. In addition, the UPLC/Q-Orbitrap-MS-Based metabolomics revealed the disrupted metabolic profiles caused by MCAO/R, and a total of 11 differential metabolites were modulated by RR administration, especially bile acids. Further correlation analysis and network pharmacology analysis also demonstrated a strong association between specific bacteria, such as Firmicutes and bile acids. In conclusion, our work demonstrated that RR could effectively ameliorate ischemic stroke by modulating the microbiota and metabolic disorders.

Notoginsenoside R1 alleviates cerebral ischemia/reperfusion injury by inhibiting the TLR4/MyD88/NF-κB signaling pathway through microbiota-gut-brain axis

BACKGROUND

Ischemic stroke (IS) ranks as the second common cause of death worldwide. However, a narrow thrombolysis timeframe and ischemia-reperfusion (I/R) injury limits patient recovery. Moreover, anticoagulation and antithrombotic drugs do not meet the clinical requirements. Studies have demonstrated close communication between the brain and gut microbiota in IS. Notoginsenoside R1 (NG-R1), a significant component of the total saponins from Panax notoginseng, has been demonstrated to be effective against cerebral I/R injury. Total saponins have been used to treat IS in Chinese pharmacopoeia. Furthermore, previous research has indicated that the absorption of NG-R1 was controlled by gut microbiota.

STUDY DESIGN

This study aimed to access the impact of NG-R1 treatment on neuroinflammation and investigate the microbiota-related mechanisms.

RESULTS

NG-R1 significantly reduced neuronal death and neuroinflammation in middle cerebral artery occlusion/reperfusion (MCAO/R) models. 16S rRNA sequencing revealed that NG-R1 treatment displayed the reversal of microbiota related with MCAO/R models. Additionally, NG-R1 administration attenuated intestinal inflammation, gut barrier destruction, and systemic inflammation. Furthermore, microbiota transplantation from NG-R1 exhibited a similar effect in the MCAO/R models.

CONCLUSION

In summary, NG-R1 treatment resulted in the restoration of the structure of the blood-brain barrier (BBB) and reduction in neuroinflammation via suppressing the stimulation of astrocytes and microglia in the cerebral ischemic area. Mechanistic research demonstrated that NG-R1 treatment suppressed the toll-like receptor 4/myeloid differentiation primary response 88/nuclear factor kappa B (TLR4/MyD88/NF-κB) signaling pathway in both the ischemic brain and colon. NG-R1 treatment enhanced microbiota dysbiosis by inhibiting the TLR4 signaling pathway to protect MCAO/R models. These findings elucidate the mechanisms by which NG-R1 improve stroke outcomes and provide some basis for Panax notoginseng saponins in clinical treatment.

Sleep apnoea, gut dysbiosis and cognitive dysfunction

Sleep disorders are becoming increasingly common, and their distinct effects on physical and mental health require elaborate investigation. Gut dysbiosis (GD) has been reported in sleep-related disorders, but sleep apnoea is of particular significance because of its higher prevalence and chronicity. Cumulative evidence has suggested a link between sleep apnoea and GD. This review highlights the gut-brain communication axis that is mediated via commensal microbes and various microbiota-derived metabolites (e.g. short-chain fatty acids, lipopolysaccharide and trimethyl amine N-oxide), neurotransmitters (e.g. γ-aminobutyric acid, serotonin, glutamate and dopamine), immune cells and inflammatory mediators, as well as the vagus nerve and hypothalamic-pituitary-adrenal axis. This review also discusses the pathological role underpinning GD and altered gut bacterial populations in sleep apnoea and its related comorbid conditions, particularly cognitive dysfunction. In addition, the review examines the preclinical and clinical evidence, which suggests that prebiotics and probiotics may potentially be beneficial in sleep apnoea and its comorbidities through restoration of eubiosis or gut microbial homeostasis that regulates neural, metabolic and immune responses, as well as physiological barrier integrity via the gut-brain axis.

Importance of good hosting: reviewing the bi-directionality of the microbiome-gut-brain-axis

Gut microorganisms have been shown to significantly impact on central function and studies that have associated brain disorders with specific bacterial genera have advocated an anomalous gut microbiome as the pathophysiological basis of several psychiatric and neurological conditions. Thus, our knowledge of brain-to-gut-to microbiome communication in this bidirectional axis seems to have been overlooked. This review examines the known mechanisms of the microbiome-to-gut-to-brain axis, highlighting how brain-to-gut-to-microbiome signaling may be key to understanding the cause of disrupted gut microbial communities. We show that brain disorders can alter the function of the brain-to-gut-to-microbiome axis, which will in turn contribute to disease progression, while the microbiome-to gut-to brain direction presents as a more versatile therapeutic axis, since current psychotropic/neurosurgical interventions may have unwanted side effects that further cause disruption to the gut microbiome. A consideration of the brain-to-gut-to-microbiome axis is imperative to better understand how the microbiome-gut-brain axis overall is involved in brain illnesses, and how it may be utilized as a preventive and therapeutic tool.

Multiomics-based molecular subtyping based on the commensal microbiome predicts molecular characteristics and the therapeutic response in breast cancer

The gut microbiota has been demonstrated to be correlated with the clinical phenotypes of diseases, including cancers. However, there are few studies on clinical subtyping based on the gut microbiota, especially in breast cancer (BC) patients. Here, using machine learning methods, we analysed the gut microbiota of BC, colorectal cancer (CRC), and gastric cancer (GC) patients to identify their shared metabolic pathways and the importance of these pathways in cancer development. Based on the gut microbiota-related metabolic pathways, human gene expression profile and patient prognosis, we established a novel BC subtyping system and identified a subtype called "challenging BC". Tumours with this subtype have more genetic mutations and a more complex immune environment than those of other subtypes. A score index was proposed for in-depth analysis and showed a significant negative correlation with patient prognosis. Notably, activation of the TPK1-FOXP3-mediated Hedgehog signalling pathway and TPK1-ITGAE-mediated mTOR signalling pathway was linked to poor prognosis in "challenging BC" patients with high scores, as validated in a patient-derived xenograft (PDX) model. Furthermore, our subtyping system and score index are effective predictors of the response to current neoadjuvant therapy regimens, with the score index significantly negatively correlated with both treatment efficacy and the number of immune cells. Therefore, our findings provide valuable insights into predicting molecular characteristics and treatment responses in "challenging BC" patients.

Periodontitis, Dental Procedures, and Young-Onset Cryptogenic Stroke

Periodontitis is associated with an increased risk of ischemic stroke, and the risk may be particularly high among young people with unexplained stroke etiology. Thus, we investigated in a case-control study whether periodontitis or recent invasive dental treatments are associated with young-onset cryptogenic ischemic stroke (CIS). We enrolled participants from a multicenter case-control SECRETO study including adults aged 18 to 49 y presenting with an imaging-positive first-ever CIS and stroke-free age- and sex-matched controls. Thorough clinical and radiographic oral examination was performed. Furthermore, we measured serum lipopolysaccharide (LPS) and lipotechoic acid (LTA) levels. Multivariate conditional regression models were adjusted for stroke risk factors, regular dentist visits, and patent foramen ovale (PFO) status. We enrolled 146 case-control pairs (median age 41.9 y; 58.2% males). Periodontitis was diagnosed in 27.5% of CIS patients and 20.1% of controls (P < 0.001). In the fully adjusted models, CIS was associated with high periodontal inflammation burden (odds ratio [OR], 95% confidence interval) with an OR of 10.48 (3.18-34.5) and severe periodontitis with an OR of 7.48 (1.24-44.9). Stroke severity increased with the severity of periodontitis, having an OR of 6.43 (1.87-23.0) in stage III to IV, grade C. Invasive dental treatments performed within 3 mo prestroke were associated with CIS, with an OR of 2.54 (1.01-6.39). Association between CIS and invasive dental treatments was especially strong among those with PFO showing an OR of 6.26 (1.72-40.2). LPS/LTA did not differ between CIS patients and controls but displayed an increasing trend with periodontitis severity. Periodontitis and recent invasive dental procedures were associated with CIS after controlling for multiple confounders. However, the role of bacteremia as a mediator of this risk was not confirmed.

Effect of Pre-Antibiotic Use Before First Stroke Incidence on Recurrence and Mortality: A Longitudinal Study Using the Korean National Health Insurance Service Database

Purpose

Clinical studies on dysbiosis and stroke outcomes has been insufficient to establish clear evidence. This study aimed to investigate the effects of pre-antibiotic use before a stroke event on secondary outcomes using a longitudinal population-level database.

Patients and Methods

This retrospective cohort study included adults aged 55 years or older diagnosed with acute ischemic stroke (AIS) and acute hemorrhagic stroke (AHS) between 2004 and 2007. Patients were followed-up until the end of 2019, and the target outcomes were secondary AIS, AHS, and all-cause mortality. Multivariable Cox regression analyses were applied, and we adjusted covariates such as age, sex, socioeconomic status, hypertension, diabetes, and dyslipidemia. Pre-antibiotic use was identified from 7 days to 1 year before the acute stroke event.

Results

We included 159,181 patients with AIS (AIS group) and 49,077 patients with AHS (AHS group). Pre-antibiotic use significantly increased the risk of secondary AIS in the AIS group (adjusted hazard ratio [aHR], 1.03; 95% confidence interval [CI], 1.01-1.05; p = 0.009) and secondary AHS in the AHS group (aHR, 1.08; 95% CI, 1.03-1.12; p <0.001). Furthermore, pre-antibiotic use in the AIS group was associated with a lower risk of mortality (aHR, 0.95; 95% CI, 0.94-0.96; p <0.001).

Conclusion

Our population-based longitudinal study revealed that pre-antibiotic use was associated with a higher risk of secondary stroke and a lower risk of mortality in the AIS and AHS groups. Further studies are needed to understand the relationship between dysbiosis and stroke outcomes.

Gut microbiome is associated with personality traits of free-ranging Tibetan macaques (Macaca thibetana)

Recent studies have emphasized that there is a strong link between the gut microbiome and the brain that affects social behavior and personality in animals. However, the interface between personality and the gut microbiome in wild primates remains poorly understood. Here, we used high-throughput sequencing and ethological methods in primate behavioral ecology to investigate the relationship between gut microbiome and personality in Tibetan macaques (Macaca thibetana). The behavioral assessment results indicated three personality dimensions including socialization, shyness, and anxiety. There was significant variation in alpha diversity only for shyness, with a significantly lower alpha diversity indices (including Shannon, Chao1, and PD) for bold individuals than for shy individuals. Using regression models to control for possible confounding factors, we found that the relative abundance of three genera, Akkermansia, Dialister, and Asteroleplasma, was significantly and positively correlated with the sociability scores in the macaques. In addition, Oscillospiraceae exhibited a positive correlation with scores for Shy Dimension. Furthermore, we found that the predicted functional genes for propionate and pyruvate, porphyrin and chlorophyll metabolic pathways related to animal behavior, were significant enriched in shyness group. We propose that the gut microbiome may play an important role in the formation of personality of Tibetan macaques.

The Water Extract of Rhubarb Prevents Ischemic Stroke by Regulating Gut Bacteria and Metabolic Pathways

Rhubarb (RR), Chinese name Dahuang, is commonly used in the treatment of ischemic stroke (IS). However, its potential mechanism is not fully elucidated. This study intended to verify the effect of RR on IS and investigate the possible mechanism of RR in preventing IS. IS in male rats was induced by embolic middle cerebral artery occlusion (MCAO) surgery, and drug administration was applied half an hour before surgery. RR dramatically decreased the neurological deficit scores, the cerebral infarct volume, and the cerebral edema rate, and improved the regional cerebral blood flow (rCBF) and histopathological changes in the brain of MCAO rats. The 16S rRNA analysis showed the harmful microbes such as Fournierella and Bilophila were decreased, and the beneficial microbes such as Enterorhabdus, Defluviitaleaceae, Christensenellaceae, and Lachnospira were significantly increased, after RR pretreatment. 1H-nuclear magnetic resonance (1H-NMR) was used to detect serum metabolomics, and RR treatment significantly changed the levels of metabolites such as isoleucine, valine, N6-acetyllysine, methionine, 3-aminoisobutyric acid, N, N-dimethylglycine, propylene glycol, trimethylamine N-oxide, myo-inositol, choline, betaine, lactate, glucose, and lipid, and the enrichment analysis of differential metabolites showed that RR may participate in the regulation of amino acid metabolism and energy metabolism. RR exerts the role of anti-IS via regulating gut bacteria and metabolic pathways.

Role of the gut microbiota in complications after ischemic stroke

Ischemic stroke (IS) is a serious central nervous system disease. Post-IS complications, such as post-stroke cognitive impairment (PSCI), post-stroke depression (PSD), hemorrhagic transformation (HT), gastrointestinal dysfunction, cardiovascular events, and post-stroke infection (PSI), result in neurological deficits. The microbiota-gut-brain axis (MGBA) facilitates bidirectional signal transduction and communication between the intestines and the brain. Recent studies have reported alterations in gut microbiota diversity post-IS, suggesting the involvement of gut microbiota in post-IS complications through various mechanisms such as bacterial translocation, immune regulation, and production of gut bacterial metabolites, thereby affecting disease prognosis. In this review, to provide insights into the prevention and treatment of post-IS complications and improvement of the long-term prognosis of IS, we summarize the interaction between the gut microbiota and IS, along with the effects of the gut microbiota on post-IS complications.

Bifidobacterium bifidum supplementation improves ischemic stroke outcomes in elderly patients: A retrospective study

This retrospective study aimed to explore the therapeutic potential of Bifidobacterium bifidum supplementation on elderly ischemic stroke patients. We retrospectively analyzed electronic medical records from 153 elderly ischemic stroke patients. Patients were stratified into 2 groups: those receiving B bifidum supplementation (Intervention group, n = 73) and those receiving standard treatment without any additional supplementation (Control group, n = 80). Outcomes were assessed using the National Institutes of Health Stroke Scale (NIHSS), Montreal Cognitive Assessment (MoCA), Self-Rating Depression Scale (SDS), and Self-Rating Anxiety Scale (SAS). Inflammatory markers, immunological indicators, neurotrophic factor, and gut-brain axis (GBA)-related markers were also evaluated at baseline and during 4-week follow-up. Compared to the control group, the intervention group exhibited significant improvements in the NIHSS, MoCA, SDS and SAS scores (P < .001). Enhanced levels of brain-derived neurotrophic factor (BDNF) and reduced levels of NPY were observed in the intervention group. Additionally, inflammatory markers, including IL-6, IL-8, IL-1β, and TNF-α, were significantly reduced in the intervention group, as well as significant increases in immunoglobulin levels (Ig A, Ig G, and Ig M) (P < .001). Besides, lower incidences of diarrhea and constipation were observed in the intervention group (P < .001), while the incidence of abdominal pain was no significant changed. B bifidum supplementation offers promising therapeutic benefits in improving neurological, cognitive, and psychological outcomes in elderly ischemic stroke patients, which may be achieved by regulating the GBA, reducing inflammation and promoting immune function. These findings highlight the importance of integrating gut health strategies in stroke management.

Recent progresses in gut microbiome mediates obstructive sleep apnea-induced cardiovascular diseases

Obstructive sleep apnea (OSA) is a multifactorial sleep disorder with a high prevalence in the general population. OSA is associated with an increased risk of developing cardiovascular diseases (CVDs), particularly hypertension, and is linked to worse outcomes. Although the correlation between OSA and CVDs is firmly established, the mechanisms are poorly understood. Continuous positive airway pressure is primary treatment for OSA reducing cardiovascular risk effectively, while is limited by inadequate compliance. Moreover, alternative treatments for cardiovascular complications in OSA are currently not available. Recently, there has been considerable attention on the significant correlation between gut microbiome and pathophysiological changes in OSA. Furthermore, gut microbiome has a significant impact on the cardiovascular complications that arise from OSA. Nevertheless, a detailed understanding of this association is lacking. This review examines recent advancements to clarify the link between the gut microbiome, OSA, and OSA-related CVDs, with a specific focus on hypertension, and also explores potential health advantages of adjuvant therapy that targets the gut microbiome in OSA.

Trans- and Cis-Phosphorylated Tau Protein: New Pieces of the Puzzle in the Development of Neurofibrillary Tangles in Post-Ischemic Brain Neurodegeneration of the Alzheimer's Disease-like Type

Recent evidence indicates that experimental brain ischemia leads to dementia with an Alzheimer's disease-like type phenotype and genotype. Based on the above evidence, it was hypothesized that brain ischemia may contribute to the development of Alzheimer's disease. Brain ischemia and Alzheimer's disease are two diseases characterized by similar changes in the hippocampus that are closely related to memory impairment. Following brain ischemia in animals and humans, the presence of amyloid plaques in the extracellular space and intracellular neurofibrillary tangles was revealed. The phenomenon of tau protein hyperphosphorylation is a similar pathological feature of both post-ischemic brain injury and Alzheimer's disease. In Alzheimer's disease, the phosphorylated Thr231 motif in tau protein has two distinct trans and cis conformations and is the primary site of tau protein phosphorylation in the pre-entanglement cascade and acts as an early precursor of tau protein neuropathology in the form of neurofibrillary tangles. Based on the latest publication, we present a similar mechanism of the formation of neurofibrillary tangles after brain ischemia as in Alzheimer's disease, established on trans- and cis-phosphorylation of tau protein, which ultimately influences the development of tauopathy.

Trimethylamine-N-oxide and cerebral stroke risk: A review

Trimethylamine-N-oxide (TMAO) is a gut microbiota-derived metabolite produced by the action of gut microbiota and the hepatic enzyme Flavin Mono‑oxygenase 3 (FMO3). TMAO level has a positive correlation with the risk of cardiovascular events, including stroke, and their level is influenced mainly by dietary choice and the action of liver enzyme FMO3. TMAO plays a role in the development of atherosclerosis plaque, which is one of the causative factors of the stroke event. Preclinical and clinical investigations on the TMAO and associated stroke risk, severity, and outcomes are summarised in this review. In addition, mechanisms of TMAO-driven vascular dysfunction are also discussed, such as inflammation, oxidative stress, thrombus and foam cell formation, altered cholesterol and bile acid metabolism, etc. Post-stroke inflammatory cascades involving activation of immune cells, i.e., microglia and astrocytes, result in Blood-brain-barrier (BBB) disruption, allowing TMAO to infiltrate the brain and further aggravate inflammation. This event occurs as a result of the activation of the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome pathway through the release of inflammatory cytokines and chemokines that further aggravate the BBB and initiate further recruitment of immune cells in the brain. Thus, it's likely that maintaining TMAO levels and associated gut microbiota could be a promising approach for treating and improving stroke complications.

Causal Associations Between Gut Microbiota and Cerebrovascular Diseases

BACKGROUND

Numerous studies suggest that the gut microbiota closely linked to cerebrovascular diseases, such as Intracranial aneurysm (IA) and aneurysmal subarachnoid hemorrhage (aSAH). Nevertheless, the confirmation of a definitive causal connection between gut microbiota, IA, and aSAH is still pending. The aim of our research is to explore the potential bidirectional causality among them.

METHODS

This bidirectional Mendelian Randomization (MR) study used single nucleotide polymorphisms linked to gut microbiota, IA, and aSAH from Genome-Wide Association Studies. The Inverse Variance Weighted (IVW) method was used to explore causality. To assess the robustness of the result, sensitivity analyses were further performed, including weighted-median method, MR-Egger regression, Maximum-likelihood method, MR pleiotropy residual sum and outlier test and leave-one-out analysis.

RESULTS

In the IVW method, the family Porphyromonadaceae (odds ratio [OR] 0.63; 95% CI 0.47-0.85; P: 0.002) and genus Bilophila (OR 0.66; 95% CI 0.50-0.86; P: 0.002) showed a significant negative association with the risk of IA. Similarly, the genus Bilophila (OR: 0.68; 95% CI: 0.50-0.93; P: 0.017) and genus Ruminococcus1 (OR: 0.48; 95% CI: 0.30-0.78; P: 0.003) were linked to reduced risk of aSAH. The sensitivity analysis yielded similar outcomes in the IVW approach. Through the adoption of reverse MR analysis, a potential correlation between IA and decreased abundance of genus Ruminococcus1 was identified (OR 0.94; 95% CI 0.90-0.99; P 0.024).

CONCLUSIONS

This MR analysis investigated the causal associations between gut microbiota, IA, and aSAH risks. The findings expanded current knowledge of the microbiota-gut-brain axis and offered novel perspectives on preventing and managing these conditions.

Protective effects of fecal microbiota transplantation against ischemic stroke and other neurological disorders: an update

The bidirectional communication between the gut and brain or gut-brain axis is regulated by several gut microbes and microbial derived metabolites, such as short-chain fatty acids, trimethylamine N-oxide, and lipopolysaccharides. The Gut microbiota (GM) produce neuroactives, specifically neurotransmitters that modulates local and central neuronal brain functions. An imbalance between intestinal commensals and pathobionts leads to a disruption in the gut microbiota or dysbiosis, which affects intestinal barrier integrity and gut-immune and neuroimmune systems. Currently, fecal microbiota transplantation (FMT) is recommended for the treatment of recurrent Clostridioides difficile infection. FMT elicits its action by ameliorating inflammatory responses through the restoration of microbial composition and functionality. Thus, FMT may be a potential therapeutic option in suppressing neuroinflammation in post-stroke conditions and other neurological disorders involving the neuroimmune axis. Specifically, FMT protects against ischemic injury by decreasing IL-17, IFN-γ, Bax, and increasing Bcl-2 expression. Interestingly, FMT improves cognitive function by lowering amyloid-β accumulation and upregulating synaptic marker (PSD-95, synapsin-1) expression in Alzheimer's disease. In Parkinson's disease, FMT was shown to inhibit the expression of TLR4 and NF-κB. In this review article, we have summarized the potential sources and methods of administration of FMT and its impact on neuroimmune and cognitive functions. We also provide a comprehensive update on the beneficial effects of FMT in various neurological disorders by undertaking a detailed interrogation of the preclinical and clinical published literature.

Role of the Gut Bacteria-Derived Metabolite Phenylacetylglutamine in Health and Diseases

Over the past few decades, it has been well established that gut microbiota-derived metabolites can disrupt gut function, thus resulting in an array of diseases. Notably, phenylacetylglutamine (PAGln), a bacterial derived metabolite, has recently gained attention due to its role in the initiation and progression of cardiovascular and cerebrovascular diseases. This meta-organismal metabolite PAGln is a byproduct of amino acid acetylation of its precursor phenylacetic acid (PAA) from a range of dietary sources like egg, meat, dairy products, etc. The microbiota-dependent metabolism of phenylalanine produces PAA, which is a crucial intermediate that is catalyzed by diverse microbial catalytic pathways. PAA conjugates with glutamine and glycine in the liver and kidney to predominantly form phenylacetylglutamine in humans and phenylacetylglycine in rodents. PAGln is associated with thrombosis as it enhances platelet activation mediated through the GPCRs receptors α2A, α2B, and β2 ADRs, thereby aggravating the pathological conditions. Clinical evidence suggests that elevated levels of PAGln are associated with pathology of cardiovascular, cerebrovascular, and neurological diseases. This Review further consolidates the microbial/biochemical synthesis of PAGln and discusses its role in the above pathophysiologies.

Identification of disordered profiles of gut microbiota and functional component in stroke and poststroke epilepsy

AIMS

It is estimated that 11.5% of patients with stroke (STR) were at risk of suffering poststroke epilepsy (PSE) within 5 years. Gut microbiota is shown to affect health in humans by producing metabolites. The association between dysregulation of gut microbiota and STR/PSE remains unclear. The aim of this study was to identify potential gut microbiota and functional component in STR and PSE, which may provide a theoretical foundation for diagnosis and treatment of STR and PSE.

METHODS

The fresh stool samples were collected from 19 healthy controls, 27 STR patients, and 20 PSE patients for 16S rRNA gene sequencing. Analysis of amplicon sequence variant and community diversity was performed, followed by the identification of dominant species, species differences analysis, diagnostic, and functional analysis of species in STR and PSE.

RESULTS

Community diversity was decreased in STR and PSE. Some disordered profiles of gut microbiota in STR and PSE were identified, such as the increase of Enterococcus and the decrease of butyricicoccus in STR, the increase of Escherichia Shigella and Clostridium innocuum-group and the decrease of Faecalibacterium in PSE, and the decrease of Anaerostipes in both STR and PSE. Moreover, potential diagnostic biomarkers for STR (butyricicoccus), PSE (Faecalibacterium), STR, and PSE (NK4A214_group and Veillonella) were identified. Several significantly dysfunctional components were identified, including l-tryptophan biosynthesis in STR, fatty acid biosynthesis in PSE, and Stress_Tolerant and anaerobic in both STR and PSE.

CONCLUSION

The disturbed gut microbiota and related dysfunctional components are closely associated with the progression of STR and PSE.

Vagus Nerve Stimulation in Ischemic Stroke

PURPOSE OF REVIEW

Vagus nerve stimulation (VNS) has emerged as a potential therapeutic approach for neurological and psychiatric disorders. In recent years, there has been increasing interest in VNS for treating ischemic stroke. This review discusses the evidence supporting VNS as a treatment option for ischemic stroke and elucidates its underlying mechanisms.

RECENT FINDINGS

Preclinical studies investigating VNS in stroke models have shown reduced infarct volumes and improved neurological deficits. Additionally, VNS has been found to reduce reperfusion injury. VNS may promote neuroprotection by reducing inflammation, enhancing cerebral blood flow, and modulating the release of neurotransmitters. Additionally, VNS may stimulate neuroplasticity, thereby facilitating post-stroke recovery. The Food and Drug Administration has approved invasive VNS (iVNS) combined with rehabilitation for ischemic stroke patients with moderate to severe upper limb deficits. However, iVNS is not feasible in acute stroke due to its time-sensitive nature. Non-invasive VNS (nVNS) may be an alternative approach for treating ischemic stroke. While the evidence from preclinical studies and clinical trials of nVNS is promising, the mechanisms through which VNS exerts its beneficial effects on ischemic stroke are still being elucidated. Therefore, further research is needed to better understand the efficacy and underlying mechanisms of nVNS in ischemic stroke. Moreover, large-scale randomized clinical trials are necessary to determine the optimal nVNS protocols, assess its long-term effects on stroke recovery and outcomes, and identify the potential benefits of combining nVNS with other rehabilitation strategies.

Gastrointestinal Dysbiosis in Neuro-Critically Ill Patients: A Systematic Review of Case-Control Studies

The human gastrointestinal tract (GIT) has a rich and pre-programmed microbiome. This microbiome is essential for physiological functions such as digestion, immunity, metabolism, and structural integrity, and of prime concern to us in conducting this study is the nervous system communication. This two-way communication between the GIT and central nervous system (CNS) is known as the gut-brain axis (GBA) and has implications for neurocritical disease. A change in any factor relating to this microbiome is known as gut dysbiosis; this can lead to aberrant communication through the GBA and in turn, can contribute to disease states. The primary objective of this study is to determine the cause-specific dysbiotic organisms in neuro-critically ill patients and their effects. We performed this study by searching published literature as per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies that defined gastrointestinal dysbiosis in neuro-critically ill patients were retrieved using Boolean search from 2000 to 2023 via PubMed and Google Scholar and narrowed the results down to five prospective case-control studies. We performed their quality assessment. The results concluded that in neurocritical illnesses such as encephalitis, brain tumors, intracerebral hemorrhage, and ischemic stroke, fluctuations in specific microbiota correlated with disease severity and prognosis. Moreover, the inhabiting population of dysbiotic organisms in neuro-critically ill patients were different in different diseases and there were no similarities in the composition of gut microbiota in these diseases. Taking stroke patients as an example; increased Enterobacteriaceae and lower Lachnospiraceae microbiome levels were found in patients with a higher stroke dysbiosis index (SDI). Those patients who developed stroke-associated pneumonia (SAP) displayed higher levels of Enterococcus species. In conclusion, dysbiosis has a major effect on neuro-critically ill patients' disease states and dysbiotic organisms can be used as a biomarker for disease. Further prospective studies on this topic are warranted for potential neurological and prognostic correlations.

Gut Microbiota in Ischemic Stroke: Role of Gut Bacteria-Derived Metabolites

Ischemic stroke (IS) remains a leading cause of death and long-term disability globally. Several mechanisms including glutamate excitotoxicity, calcium overload, neuroinflammation, oxidative stress, mitochondrial damage, and apoptosis are known to be involved in the pathogenesis of IS, but the underlying pathophysiology mechanisms of IS are not fully clarified. During the past decade, gut microbiota were recognized as a key regulator to affect the health of the host either directly or via their metabolites. Recent studies indicate that gut bacterial dysbiosis is closely related to hypertension, diabetes, obesity, dyslipidemia, and metabolic syndrome, which are the main risk factors for cardiovascular diseases. Increasing evidence indicates that IS can lead to perturbation in gut microbiota and increased permeability of the gut mucosa, known as "leaky gut," resulting in endotoxemia and bacterial translocation. In turn, gut dysbiosis and impaired intestinal permeability can alter gut bacterial metabolite signaling profile from the gut to the brain. Microbiota-derived products and metabolites, such as short-chain fatty acids (SCFAs), bile acids (BAs), trimethylamine N-oxide (TMAO), lipopolysaccharides (LPS), and phenylacetylglutamine (PAGln) can exert beneficial or detrimental effects on various extraintestinal organs, including the brain, liver, and heart. These metabolites have been increasingly acknowledged as biomarkers and mediators of IS. However, the specific role of the gut bacterial metabolites in the context of stroke remains incompletely understood. In-depth studies on these products and metabolites may provide new insight for the development of novel therapeutics for IS.

Molecular Aspects of MAFLD-New Insights on Pathogenesis and Treatment

Metabolic-associated liver disease (MAFLD) affects up to 70% of overweight and more than 90% of morbidly obese people, and its pathogenesis is rather complex and multifactorial. The criteria for MAFLD include the presence of hepatic steatosis in addition to one of the following three criteria: overweight or obesity, presence of type 2 diabetes mellitus (T2DM), or evidence of metabolic dysregulation. If the specific criteria are present, the diagnosis of MAFLD can be made regardless of alcohol consumption and previous liver disease. The pathophysiological mechanisms of MAFLD, including inflammation, lipotoxicity, mitochondrial disfunction, and oxidative stress, as well as the impact of intestinal gut microbiota, are constantly being elucidated. Treatment strategies that are continually emerging are based on different key points in MAFLD pathogenesis. Yet, the ideal therapeutic option has still not been found and future research is of great importance, as MAFLD represents a multisystemic disease with numerous complications.

Changes of gut microbiota in patients at different phases of stroke

AIMS

Gut dysbiosis appears rapidly after acute stroke and may affect the prognosis, whereas changes in gut microbiota with gradual recovery from stroke are unknown and rarely studied. The purpose of this study is to explore the characteristics of gut microbiota changes over time after stroke.

METHODS

Stroke patients and healthy subjects were selected to compare the clinical data and gut microbiota of the patient group in two phases with that of healthy subjects and 16S rRNA gene sequencing was used to search the differences of gut microbiota in subjects.

RESULTS

Compared with the healthy subjects, the subacute patients mainly decreased the abundance of some gut microbial communities, while the decreased communities reduced and more communities increased the abundance in the convalescent patients. The abundance of Lactobacillaceae increased in both phases in patient group, while Butyricimona, Peptostreptococaceae and Romboutsia decreased in both phases. Correlation analysis found that the MMSE scores of patients in the two phases had the greatest correlation with the gut microbiota.

CONCLUSION

Gut dysbiosis still existed in patients in the subacute phase and convalescent phase, and gradually improved with the recovery of stroke. Gut microbiota may affect the prognosis of stroke by affecting BMI and/or related indicators, and there is a strong correlation between gut microbiota and cognitive function after stroke.

Signaling pathways in brain ischemia: Mechanisms and therapeutic implications

Ischemic stroke occurs when the arteries supplying blood to the brain are narrowed or blocked, inducing damage to brain tissue due to a lack of blood supply. One effective way to reduce brain damage and alleviate symptoms is to reopen blocked blood vessels in a timely manner and reduce neuronal damage. To achieve this, researchers have focused on identifying key cellular signaling pathways that can be targeted with drugs. These pathways include oxidative/nitrosative stress, excitatory amino acids and their receptors, inflammatory signaling molecules, metabolic pathways, ion channels, and other molecular events involved in stroke pathology. However, evidence suggests that solely focusing on protecting neurons may not yield satisfactory clinical results. Instead, researchers should consider the multifactorial and complex mechanisms underlying stroke pathology, including the interactions between different components of the neurovascular unit. Such an approach is more representative of the actual pathological process observed in clinical settings. This review summarizes recent research on the multiple molecular mechanisms and drug targets in ischemic stroke, as well as recent advances in novel therapeutic strategies. Finally, we discuss the challenges and future prospects of new strategies based on the biological characteristics of stroke.

Integrative Approaches in Acute Ischemic Stroke: From Symptom Recognition to Future Innovations

Among the high prevalence of cerebrovascular diseases nowadays, acute ischemic stroke stands out, representing a significant worldwide health issue with important socio-economic implications. Prompt diagnosis and intervention are important milestones for the management of this multifaceted pathology, making understanding the various stroke-onset symptoms crucial. A key role in acute ischemic stroke management is emphasizing the essential role of a multi-disciplinary team, therefore, increasing the efficiency of recognition and treatment. Neuroimaging and neuroradiology have evolved dramatically over the years, with multiple approaches that provide a higher understanding of the morphological aspects as well as timely recognition of cerebral artery occlusions for effective therapy planning. Regarding the treatment matter, the pharmacological approach, particularly fibrinolytic therapy, has its merits and challenges. Endovascular thrombectomy, a game-changer in stroke management, has witnessed significant advances, with technologies like stent retrievers and aspiration catheters playing pivotal roles. For select patients, combining pharmacological and endovascular strategies offers evidence-backed benefits. The aim of our comprehensive study on acute ischemic stroke is to efficiently compare the current therapies, recognize novel possibilities from the literature, and describe the state of the art in the interdisciplinary approach to acute ischemic stroke. As we aspire for holistic patient management, the emphasis is not just on medical intervention but also on physical therapy, mental health, and community engagement. The future holds promising innovations, with artificial intelligence poised to reshape stroke diagnostics and treatments. Bridging the gap between groundbreaking research and clinical practice remains a challenge, urging continuous collaboration and research.

Therapeutic Effects of Baicalin on Diseases Related to Gut-Brain Axis Dysfunctions

The gut-brain axis is an active area of research. Several representative diseases, including central nervous system disorders (Alzheimer's disease, Parkinson's disease, and depression), metabolic disorders (obesity-related diseases), and intestinal disorders (inflammatory bowel disease and dysbiosis), are associated with the dysfunctional gut-brain axis. Baicalin, a bioactive flavonoid extracted from Scutellaria baicalensis, is reported to exert various pharmacological effects. This narrative review summarizes the molecular mechanisms and potential targets of baicalin in disorders of the gut-brain axis. Baicalin protects the central nervous system through anti-neuroinflammatory and anti-neuronal apoptotic effects, suppresses obesity through anti-inflammatory and antioxidant effects, and alleviates intestinal disorders through regulatory effects on intestinal microorganisms and short-chain fatty acid production. The bioactivities of baicalin are mediated through the gut-brain axis. This review comprehensively summarizes the regulatory role of baicalin in gut-brain axis disorders, laying a foundation for future research, although further confirmatory basic research is required.