Influence of Gut and Lung Microbiota and the Gut-Lung Axis on Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia(BPD),also known as neonatal chronic lung disease,is a common respiratory disease in preterm infants.Preterm infants with BPD often exhibit changes in gut and lung microbiota.In recent years,with the development of high-throughput sequencing technology,more and more mechanisms of the gut-lung axis have been confirmed,helping to explore new directions for the treatment of BPD using microecological agents.This paper reviews the roles of gut microbiota,lung microbiota,and the gut-lung axis in the pathogenesis of BPD in preterm infants,providing new research avenues for the prevention and treatment of BPD.

Herbal medicine in the treatment of COVID-19 based on the gut-lung axis

Respiratory symptoms are most commonly experienced by patients in the early stages of novel coronavirus disease 2019 (COVID-19). However, with a better understanding of COVID-19, gastrointestinal symptoms such as diarrhea, nausea, and vomiting haveattracted increasing attention. The gastrointestinal tract may be a target organ of severe acute respiratory syndrome coronavirus2 (SARS-CoV-2) infection. The intestinal microecological balance is a crucial factor for homeostasis, including immunity andinflammation, which are closely related to COVID-19. Herbal medicine can restore intestinal function and regulate the gut florastructure. Herbal medicine has a long history of treating lung diseases from the perspective of the intestine, which is called thegut-lung axis. The physiological activities of guts and lungs influence each other through intestinal flora, microflora metabolites,and mucosal immunity. Microecological modulators are included in the diagnosis and treatment protocols for COVID-19. Inthis review, we demonstrate the relationship between COVID-19 and the gut, gut-lung axis, and the role of herbal medicine intreating respiratory diseases originating from the intestinal tract. It is expected that the significance of herbal medicine in treatingrespiratory diseases from the perspective of the intestinal tract could lead to new ideas and methods for treatment.

Immune regulation of the gut-brain axis and lung-brain axis involved in ischemic stroke

Local ischemia often causes a series of inflammatory reactions when both brain immune cells and the peripheral immune response are activated.In the human body,the gut and lung are regarded as the key reactional targets that are initiated by brain ischemic attacks.Mucosal microorganisms play an important role in immune regulation and metabolism and affect blood-brain barrier permeability.In addition to the relationship between peripheral organs and central areas and the intestine and lung also interact among each other.Here,we review the molecular and cellular immune mechanisms involved in the pathways of inflammation across the gut-brain axis and lung-brain axis.We found that abnormal intestinal flora,the intestinal microenvironment,lung infection,chronic diseases,and mechanical ventilation can worsen the outcome of ischemic stroke.This review also introduces the influence of the brain on the gut and lungs after stroke,highlighting the bidirectional feedback effect among the gut,lungs,and brain.

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 thatα-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.

Cellular interplay to 3D in vitro microphysiological disease model:cell patterning microbiota-gut-brain axis

The microbiota-gut-brain axis(MGBA)has emerged as a key prospect in the bidirectional communication between two major organ systems:the brain and the gut.Homeostasis between the two organ systems allows the body to function without disease,whereas dysbiosis has long-standing evidence of etiopathological conditions.The most common communication paths are the microbial release of metabolites,soluble neurotransmitters,and immune cells.However,each pathway is intertwined with a complex one.With the emergence of in vitro models and the popularity of three-dimensional(3D)cultures and Transwells,engineering has become easier for the scientific understanding of neurodegenerative diseases.This paper briefly retraces the possible communication pathways between the gut microbiome and the brain.It further elaborates on three major diseases:autism spectrum disorder,Parkinson’s disease,and Alzheimer’s disease,which are prevalent in children and the elderly.These diseases also decrease patients’quality of life.Hence,understanding them more deeply with respect to current advances in in vitro modeling is crucial for understanding the diseases.Remodeling of MGBA in the laboratory uses many molecular technologies and biomaterial advances.Spheroids and organoids provide a more realistic picture of the cell and tissue structure than monolayers.Combining them with the Transwell system offers the advantage of compartmentalizing the two systems(apical and basal)while allowing physical and chemical cues between them.Cutting-edge technologies,such as bioprinting and microfluidic chips,might be the future of in vitro modeling,as they provide dynamicity.

Research progress on insomnia treated by traditional Chinese medicine and acupuncture based on microbial-gut-brain axis theory

Insomnia,as one of the emotional diseases,has been increasing in recent years,which has a great impact on people's life and work.Therefore,researchers are eager to find a more perfect treatment.The microbiome-gut-brain axis is a new theory that has gradually become popular abroad in recent years and has a profound impact in the field of insomnia.In recent years,traditional Chinese medicine(TCM)has played an increasingly important role in the treatment of insomnia,especially acupuncture and Chinese herbal medicine.It is the main method of TCM in the treatment of insomnia.This paper mainly reviews the combination degree of"microorganism-gut-brain axis"theory with TCM and acupuncture under the system of TCM.To explore the mechanism of TCM and acupuncture in the treatment of insomnia under the guidance of"microorganismgut-brain axis"theory,in order to provide a new idea for the diagnosis and treatment of insomnia.

Correlation between the neuroendocrine axis,microbial species,inflammatory response,and gastrointestinal symptoms in irritable bowel syndrome

BACKGROUND This study examines the complex relationships among the neuroendocrine axis,gut microbiome,inflammatory responses,and gastrointestinal symptoms in patients with irritable bowel syndrome(IBS).The findings provide new insights into the pathophysiology of IBS and suggest potential therapeutic targets for improving patient outcomes.AIM To investigate the interactions between the neuroendocrine axis,gut microbiome,inflammation,and gastrointestinal symptoms in patients with IBS.METHODS Patients diagnosed with IBS between January 2022 and January 2023 were selected for the study.Healthy individuals undergoing routine check-ups during the same period served as the control group.Data were collected on neuroendocrine hormone levels,gut microbiome profiles,inflammatory biomarkers,and gastrointestinal symptomatology to analyze their interrelations and their potential roles in IBS pathogenesis.RESULTS IBS patients exhibited significant dysregulation of the neuroendocrine axis,with altered levels of cortisol,serotonin,and neuropeptides compared to healthy controls.The gut microbiome of IBS patients showed reduced diversity and specific alterations in bacterial genera,including Bifidobacterium,Lactobacillus,and Faecalibacterium,which were associated with neuroendocrine disturbances.Additionally,elevated levels of inflammatory markers,such as C-reactive protein,interleukin-6,and tumor necrosis factor-α,were observed and correlated with the severity of gastrointestinal symptoms like abdominal pain,bloating,and altered bowel habits.CONCLUSION The findings suggest that targeting the neuroendocrine axis,gut microbiome,and inflammatory pathways may offer novel therapeutic strategies to alleviate symptoms and improve the quality of life in IBS patients.

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

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 r RNA amplicon sequencing and liquid chromatography-mass spectrometry to analyze changes in the microbiome and serum metabolome following magnesium-Lthreonate 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 magnesiumL-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.

Irisin/BDNF signaling in the muscle-brain axis and circadian system: A review

In mammals,the timing of physiological,biochemical and behavioral processes over a 24-h period is controlled by circadian rhythms.To entrain the master clock located in the suprachiasmatic nucleus of the hypothalamus to a precise 24-h rhythm,environmental zeitgebers are used by the circadian system.This is done primarily by signals from the retina via the retinohypothalamic tract,but other cues like exercise,feeding,temperature,anxiety,and social events have also been shown to act as non-photic zeitgebers.The recently identified myokine irisin is proposed to serve as an entraining non-photic signal of exercise.Irisin is a product of cleavage and modification from its precursor membrane fibronectin typeⅢdomain-containing protein 5(FNDC5)in response to exercise.Apart from well-known peripheral effects,such as inducing the"browning"of white adipocytes,irisin can penetrate the blood-brain barrier and display the effects on the brain.Experimental data suggest that FNDC5/irisin mediates the positive effects of physical activity on brain functions.In several brain areas,irisin induces the production of brain-derived neurotrophic factor(BDNF).In the master clock,a significant role in gating photic stimuli in the retinohypothalamic synapse for BDNF is suggested.However,the brain receptor for irisin remains unknown.In the current review,the interactions of physical activity and the irisin/BDNF axis with the circadian system are reconceptualized.

Low-intensity pulsed ultrasound reduces alveolar bone resorption during orthodontic treatment via Lamin A/C-Yes-associated protein axis in stem cells

BACKGROUND The bone remodeling during orthodontic treatment for malocclusion often requires a long duration of around two to three years,which also may lead to some complications such as alveolar bone resorption or tooth root resorption.Low-intensity pulsed ultrasound(LIPUS),a noninvasive physical therapy,has been shown to promote bone fracture healing.It is also reported that LIPUS could reduce the duration of orthodontic treatment;however,how LIPUS regulates the bone metabolism during the orthodontic treatment process is still unclear.AIM To investigate the effects of LIPUS on bone remodeling in an orthodontic tooth movement(OTM)model and explore the underlying mechanisms.METHODS A rat model of OTM was established,and alveolar bone remodeling and tooth movement rate were evaluated via micro-computed tomography and staining of tissue sections.In vitro,human bone marrow mesenchymal stem cells(hBMSCs)were isolated to detect their osteogenic differentiation potential under compression and LIPUS stimulation by quantitative reverse transcription-polymerase chain reaction,Western blot,alkaline phosphatase(ALP)staining,and Alizarin red staining.The expression of Yes-associated protein(YAP1),the actin cytoskeleton,and the Lamin A/C nucleoskeleton were detected with or without YAP1 small interfering RNA(siRNA)application via immunofluorescence.RESULTS The force treatment inhibited the osteogenic differentiation potential of hBMSCs;moreover,the expression of osteogenesis markers,such as type 1 collagen(COL1),runt-related transcription factor 2,ALP,and osteocalcin(OCN),decreased.LIPUS could rescue the osteogenic differentiation of hBMSCs with increased expression of osteogenic marker inhibited by force.Mechanically,the expression of LaminA/C,F-actin,and YAP1 was downregulated after force treatment,which could be rescued by LIPUS.Moreover,the osteogenic differentiation of hBMSCs increased by LIPUS could be attenuated by YAP siRNA treatment.Consistently,LIPUS increased alveolar bone density and decreased vertical bone absorption in vivo.The decreased expression of COL1,OCN,and YAP1 on the compression side of the alveolar bone was partially rescued by LIPUS.CONCLUSION LIPUS can accelerate tooth movement and reduce alveolar bone resorption by modulating the cytoskeleton-Lamin A/C-YAP axis,which may be a promising strategy to reduce the orthodontic treatment process.

In situ calibrated angle between the quantization axis and the propagating direction of the light field for trapping neutral atoms

The recently developed magic-intensity trapping technique of neutral atoms efficiently mitigates the detrimental effect of light shifts on atomic qubits and substantially enhances the coherence time. This technique relies on applying a bias magnetic field precisely parallel to the wave vector of a circularly polarized trapping laser field. However, due to the presence of the vector light shift experienced by the trapped atoms, it is challenging to precisely define a parallel magnetic field, especially at a low bias magnetic field strength, for the magic-intensity trapping of85Rb qubits. In this work, we present a method to calibrate the angle between the bias magnetic field and the trapping laser field with the compensating magnetic fields in the other two directions orthogonal to the bias magnetic field direction. Experimentally, with a constantdepth trap and a fixed bias magnetic field, we measure the respective resonant frequencies of the atomic qubits in a linearly polarized trap and a circularly polarized one via the conventional microwave Rabi spectra with different compensating magnetic fields and obtain the corresponding total magnetic fields via the respective resonant frequencies using the Breit–Rabi formula. With known total magnetic fields, the angle is a function of the other two compensating magnetic fields.Finally, the projection value of the angle on either of the directions orthogonal to the bias magnetic field direction can be reduced to 0(4)° by applying specific compensating magnetic fields. The measurement error is mainly attributed to the fluctuation of atomic temperature. Moreover, it also demonstrates that, even for a small angle, the effect is strong enough to cause large decoherence of Rabi oscillation in a magic-intensity trap. Although the compensation method demonstrated here is explored for the magic-intensity trapping technique, it can be applied to a variety of similar precision measurements with trapped neutral atoms.

Single nucleus/cell RNA-seq of the chicken hypothalamicpituitaryovarian axis offers new insights into the molecular regulatory mechanisms of ovarian development

The hypothalamic-pituitary-ovarian(HPO)axis represents a central neuroendocrine network essential for reproductive function.Despite its critical role,the intrinsic heterogeneity within the HPO axis across vertebrates and the complex intercellular interactions remain poorly defined.This study provides the first comprehensive,unbiased,cell type-specific molecular profiling of all three components of the HPO axis in adult Lohmann layers and Liangshan Yanying chickens.Within the hypothalamus,pituitary,and ovary,seven,12,and 13 distinct cell types were identified,respectively.Results indicated that the pituitary adenylate cyclase activating polypeptide(PACAP),follicle-stimulating hormone(FSH),and prolactin(PRL)signaling pathways may modulate the synthesis and secretion of gonadotropin-releasing hormone(GnRH),FSH,and luteinizing hormone(LH)within the hypothalamus and pituitary.In the ovary,interactions between granulosa cells and oocytes involved the KIT,CD99,LIFR,FN1,and ANGPTL signaling pathways,which collectively regulate follicular maturation.The SEMA4 signaling pathway emerged as a critical mediator across all three tissues of the HPO axis.Additionally,gene expression analysis revealed that relaxin 3(RLN3),gastrin-releasing peptide(GRP),and cocaine-and amphetamine regulated transcripts(CART,also known as CARTPT)may function as novel endocrine hormones,influencing the HPO axis through autocrine,paracrine,and endocrine pathways.Comparative analyses between Lohmann layers and Liangshan Yanying chickens demonstrated higher expression levels of GRP,RLN3,CARTPT,LHCGR,FSHR,and GRPR in the ovaries of Lohmann layers,potentially contributing to their superior reproductive performance.In conclusion,this study provides a detailed molecular characterization of the HPO axis,offering novel insights into the regulatory mechanisms underlying reproductive biology.

Curcumin inhibits colorectal cancer development by blocking the YAP/TAZ signaling axis

Background:Curcumin is a plant polyphenol with antitumor properties and inhibits the development of colorectal cancer(CRC).However,as the molecular mechanism associated is still unclear,our study aimed to explore the underlying molecular mechanisms by which curcumin inhibits CRC.Methods:HT29 and SW480 cells were treated with curcumin or/and Doxycycline(DOX),and cell viability,colony forming ability,migration and invasion were confirmed by cell counting kit-8(CCK-8),colony forming,Transwell assays.And Yes-associated protein 1(YAP)and PDZ-binding motif(TAZ)signaling-related genes or proteins were analyzed using reverse transcription quantitative real-time PCR(RT-qPCR),western blot,and immunofluorescence assays.Then nude mice xenograft tumor model was constructed,YAP and Ki67 expressions were tested by immunohistochemistry(IHC)staining.Results:In our study,we proved that curcumin significantly inhibited the CRC cell viability,cell migration,and cell invasion abilities.In addition,curcumin inhibited YAP and Transcriptional coactivator with TAZ or the YAP/TAZ signaling axis in CRC cells.Further,in the nude mice model,curcumin treatment significantly decreased the size and weight of xenotransplant tumors.Conclusion:Therefore,curcumin significantly inhibited CRC development and invasion by regulating the YAP/TAZ signaling axis.

Traditional Chinese medicine treatment of insomnia based on microbial-gut-brain axis theory

In recent years,insomnia has gradually become a common disease in society,which seriously affects people's quality of life.At present,with the deepening of research on intestinal microbiota-gut-brain axis in Western medicine,many studies suggest that regulating the gastrointestinal tract can treat brain-related diseases.It is found that brain-gut-bacteria axis plays an important role in the prevention and treatment of primary insomnia.At present,although the clinical treatment of insomnia with Western medicine can improve the insomnia symptoms of patients to a certain extent,there are still obvious adverse reactions,such as anxiety and depression,drug addiction,etc.,so long-term oral drug therapy cannot be carried out.Traditional Chinese medicine(TCM)and acu-puncture techniques have certain therapeutic effects on insomnia.TCM believes that the brain and gastrointestinal system are connected through the meridian,and the pathophysiology is closely related.This paper will discuss the theory and feasibility of TCM for the treatment of insomnia from the pathological relation-ship between brain-gut axis,intestinal flora and insomnia.

Importance of the gut microbiota in the gut-liver axis in normal and liver disease

The gut microbiota is of growing interest to clinicians and researchers.This is because there is a growing understanding that the gut microbiota performs many different functions,including involvement in metabolic and immune processes that are systemic in nature.The liver,with its important role in detoxifying and metabolizing products from the gut,is at the forefront of interactions with the gut microbiota.Many details of these interactions are not yet known to clinicians and researchers,but there is growing evidence that normal gut microbiota function is important for liver health.At the same time,factors affecting the gut microbiota,including nutrition or medications,may also have an effect through the gut-liver axis.

‘Beijing Central Axis:A Building Ensemble Exhibiting the Ideal Order of the Chinese Capital’ Successfully Inscribed on the World Heritage List

Beijing Central Axis runs from north to south through the old city of Beijing.It was initially constructed in the 13th century and took shape in the 16th century.Over centuries of development,it has evolved into the world's longest urban axis,stretching 7.8 kilometers today.

Beijing’s Central Axis through the Lens of a German Photographer

A central axis represents the core of a city’s culture,signifying its features and identity.STRETCHING from the Bell Tower and the Drum Tower in the north,to the Yongding Gate in the south,the 7.8 kilometer Beijing Central Axis has been the“cultural backbone”of the city for hundreds of years.Seen from the Drum Tower,the Central Axis is like a scroll of historical stories unfolding along its route,engendering a string of emotions in its many viewers.

The gut-eye axis:from brain neurodegenerative diseases to age-related macular degeneration

Age-related macular degeneration is a serious neurodegenerative disease of the retina that significantly impacts vision.Unfortunately,the specific pathogenesis remains unclear,and effective early treatment options are consequently lacking.The microbiome is defined as a large ecosystem of microorganisms living within and coexisting with a host.The intestinal microbiome undergoes dynamic changes owing to age,diet,genetics,and other factors.Such dysregulation of the intestinal flora can disrupt the microecological balance,resulting in immunological and metabolic dysfunction in the host,and affecting the development of many diseases.In recent decades,significant evidence has indicated that the intestinal flora also influences systems outside of the digestive tract,including the brain.Indeed,several studies have demonstrated the critical role of the gut-brain axis in the development of brain neurodegenerative diseases,including Alzheimer’s disease and Parkinson’s disease.Similarly,the role of the“gut-eye axis”has been confirmed to play a role in the pathogenesis of many ocular disorders.Moreover,age-related macular degeneration and many brain neurodegenerative diseases have been shown to share several risk factors and to exhibit comparable etiologies.As such,the intestinal flora may play an important role in age-related macular degeneration.Given the above context,the present review aims to clarify the gut-brain and gut-eye connections,assess the effect of intestinal flora and metabolites on age-related macular degeneration,and identify potential diagnostic markers and therapeutic strategies.Currently,direct research on the role of intestinal flora in age-related macular degeneration is still relatively limited,while studies focusing solely on intestinal flora are insufficient to fully elucidate its functional role in age-related macular degeneration.Organ-on-a-chip technology has shown promise in clarifying the gut-eye interactions,while integrating analysis of the intestinal flora with research on metabolites through metabolomics and other techniques is crucial for understanding their potential mechanisms.

Heyingwuzi formulation alleviates diabetic retinopathy by promoting mitophagy via the HIF-1α/BNIP3/NIX axis

BACKGROUND Diabetic retinopathy(DR)is the primary cause of visual problems in patients with diabetes.The Heyingwuzi formulation(HYWZF)is effective against DR.AIM To determine the HYWZF prevention mechanisms,especially those underlying mitophagy.METHODS Human retinal capillary endothelial cells(HRCECs)were treated with high glucose(hg),HYWZF serum,PX-478,or Mdivi-1 in vitro.Then,cell counting kit-8,transwell,and tube formation assays were used to evaluate HRCEC proliferation,invasion,and tube formation,respectively.Transmission electron microscopy was used to assess mitochondrial morphology,and Western blotting was used to determine the protein levels.Flow cytometry was used to assess cell apoptosis,reactive oxygen species(ROS)production,and mitochondrial membrane potential.Moreover,C57BL/6 mice were established in vivo using streptozotocin and treated with HYWZF for four weeks.Blood glucose levels and body weight were monitored continuously.Changes in retinal characteristics were evaluated using hematoxylin and eosin,tar violet,and periodic acid-Schiff staining.Protein levels in retinal tissues were determined via Western blotting,immunohistochemistry,and immunostaining.RESULTS HYWZF inhibited excessive ROS production,apoptosis,tube formation,and invasion in hg-induced HRCECs via mitochondrial autophagy in vitro.It increased the mRNA expression levels of BCL2-interacting protein 3(BNIP3),FUN14 domain-containing 1,BNIP3-like(BNIP3L,also known as NIX),PARKIN,PTEN-induced kinase 1,and hypoxia-inducible factor(HIF)-1α.Moreover,it downregulated the protein levels of vascular endothelial cell growth factor and increased the light chain 3-II/I ratio.However,PX-478 and Mdivi-1 reversed these effects.Additionally,PX-478 and Mdivi-1 rescued the effects of HYWZF by decreasing oxidative stress and apoptosis and increasing mitophagy.HYWZF intervention improved the symptoms of diabetes,tissue damage,number of acellular capillaries,and oxidative stress in vivo.Furthermore,in vivo experiments confirmed the results of in vitro experiments.CONCLUSION HYWZF alleviated DR and associated damage by promoting mitophagy via the HIF-1α/BNIP3/NIX axis.

Gut microbiota-astrocyte axis: new insights into age-related cognitive decline

With the rapidly aging human population,age-related cognitive decline and dementia are becoming increasingly prevalent worldwide.Aging is considered the main risk factor for cognitive decline and acts through alterations in the composition of the gut microbiota,microbial metabolites,and the functions of astrocytes.The microbiota–gut–brain axis has been the focus of multiple studies and is closely associated with cognitive function.This article provides a comprehensive review of the specific changes that occur in the composition of the gut microbiota and microbial metabolites in older individuals and discusses how the aging of astrocytes and reactive astrocytosis are closely related to age-related cognitive decline and neurodegenerative diseases.This article also summarizes the gut microbiota components that affect astrocyte function,mainly through the vagus nerve,immune responses,circadian rhythms,and microbial metabolites.Finally,this article summarizes the mechanism by which the gut microbiota–astrocyte axis plays a role in Alzheimer’s and Parkinson’s diseases.Our findings have revealed the critical role of the microbiota–astrocyte axis in age-related cognitive decline,aiding in a deeper understanding of potential gut microbiome-based adjuvant therapy strategies for this condition.