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Thakur P, Baraskar K, Shrivastava VK, Medhi B. Cross-talk between adipose tissue and microbiota-gut-brain-axis in brain development and neurological disorder. Brain Res 2024; 1844:149176. [PMID: 39182900 DOI: 10.1016/j.brainres.2024.149176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 07/25/2024] [Accepted: 08/18/2024] [Indexed: 08/27/2024]
Abstract
The gut microbiota is an important factor responsible for the physiological processes as well as pathogenesis of host. The communication between central nervous system (CNS) and microbiota occurs by different pathways i.e., chemical, neural, immune, and endocrine. Alteration in gut microbiota i.e., gut dysbiosis causes alteration in the bidirectional communication between CNS and gut microbiota and linked to the pathogenesis of neurological and neurodevelopmental disorder. Therefore, now-a-days microbiota-gut-brain-axis (MGBA) has emerged as therapeutic target for the treatment of metabolic disorder. But, experimental data available on MGBA from basic research has limited application in clinical study. In present study we first summarized molecular mechanism of microbiota interaction with brain physiology and pathogenesis via collecting data from different sources i.e., PubMed, Scopus, Web of Science. Furthermore, evidence shows that adipose tissue (AT) is active during metabolic activities and may also interact with MGBA. Hence, in present study we have focused on the relationship among MGBA, brown adipose tissue, and white adipose tissue. Along with this, we have also studied functional specificity of AT, and understanding heterogeneity among MGBA and different types of AT. Therefore, molecular interaction among them may provide therapeutic target for the treatment of neurological disorder.
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Affiliation(s)
- Pratibha Thakur
- Endocrinology Unit, Bioscience Department, Barkatullah University, Bhopal, Madhya Pradesh 462026, India.
| | - Kirti Baraskar
- Endocrinology Unit, Bioscience Department, Barkatullah University, Bhopal, Madhya Pradesh 462026, India
| | - Vinoy K Shrivastava
- Endocrinology Unit, Bioscience Department, Barkatullah University, Bhopal, Madhya Pradesh 462026, India
| | - Bikash Medhi
- Department of Pharmacology, Post Graduate Institute of Medical Education and Research, Chandigarh, Punjab 160012, India.
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Niu Q, Li D, Zhang J, Piao Z, Xu B, Xi Y, Mohamed Kamal NNSN, Lim V, Li P, Yin Y. The new perspective of Alzheimer's Disease Research: Mechanism and therapeutic strategy of neuronal senescence. Ageing Res Rev 2024; 102:102593. [PMID: 39566741 DOI: 10.1016/j.arr.2024.102593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2024] [Accepted: 11/16/2024] [Indexed: 11/22/2024]
Abstract
Alzheimer's disease (AD), commonly known as senile dementia, is a neurodegenerative disease with insidious onset and gradually worsening course. The brain is particularly sensitive to senescence, and neuronal senescence is an important risk factor for the occurrence of AD. However, the exact pathogenesis between neuronal senescence and AD has not been fully elucidated so far. Neuronal senescence is characterized by the permanent stagnation of the cell cycle, and the changes in its structure, function, and microenvironment are closely related to the pathogenesis and progression of AD. In recent years, studies such as the Aβ cascade hypothesis and Tau protein phosphorylation have provided new strategies for the therapy of AD, but due to the complexity of the etiology of AD, there are still no effective treatment measures. This article aims to deeply analyze the pathogenesis between AD and neuronal senescence, and sort out various existing therapeutic methods, to provide new ideas and references for the clinical treatment of AD.
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Affiliation(s)
- Qianqian Niu
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang 453003, China; Department of Toxicology, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Penang 13200, Malaysia
| | - Danjie Li
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, School of Pharmacy, Xinxiang 453003, China
| | - Jiayin Zhang
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, School of Pharmacy, Xinxiang 453003, China
| | - Zhengji Piao
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, School of Pharmacy, Xinxiang 453003, China
| | - Bo Xu
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, School of Pharmacy, Xinxiang 453003, China
| | - Yuting Xi
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, School of Pharmacy, Xinxiang 453003, China
| | - Nik Nur Syazni Nik Mohamed Kamal
- Department of Toxicology, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Penang 13200, Malaysia; Dementia Multidisciplinary Research Program of IPPT (DMR-IPPT), Advanced Medical and Dental Institute, Universiti Sains Malaysia, Penang 13200, Malaysia.
| | - Vuanghao Lim
- Department of Toxicology, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Penang 13200, Malaysia.
| | - Peng Li
- Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, School of Pharmacy, Xinxiang 453003, China.
| | - Yaling Yin
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang 453003, China.
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Wang Y, Ding P, Zhang K, Xu X, Li H. Correlation Between Regulation of Intestinal Flora by Danggui-Shaoyao-San and Improvement of Cognitive Impairment in Mice With Alzheimer's Disease. Brain Behav 2024; 14:e70110. [PMID: 39482855 PMCID: PMC11527834 DOI: 10.1002/brb3.70110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Revised: 09/21/2024] [Accepted: 10/06/2024] [Indexed: 11/03/2024] Open
Abstract
PURPOSE The abnormal central glucose metabolism in Alzheimer's disease (AD) is related to the brain-gut axis. This study aims to explore the target of Danggui-Shaoyao-San (DSS) in improving cognitive impairment. METHOD This study analyzed the differences in mice intestinal flora by 16S rRNA sequencing. The cognitive protective effects of DSS were observed through the Morris water maze and the new object recognition. The mitigation effects of DSS on Aβ and p-tau, regulatory effects on glucose metabolism targets, and intestinal structure effects were observed through brain and colon slices staining. The differences in neural ultrastructure were compared by transmission electron microscopy. FINDING The results showed that DSS affected the composition of intestinal dominant bacteria and bacteria genera and regulated the abundance of intestinal bacteria in AD mice. DSS improved the behavior of AD mice, alleviated the deposition of AD pathological products in the brain and colon, regulated the expression of glycometabolism-related proteins, and improved the colon barrier structure and neural ultrastructure in the brain of mice with AD. CONCLUSION Our findings suggest that DSS may affect AD central glucose metabolism and improve cognition by regulating the gut-brain axis.
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Affiliation(s)
- Ya‐Han Wang
- Department of NeurologyAffiliated Hospital of Shandong University of Traditional Chinese MedicineJinanChina
| | - Peng‐Li Ding
- The First Clinical Medical CollegeShandong University of Traditional Chinese MedicineJinanChina
| | - Kai‐Xin Zhang
- The First Clinical Medical CollegeShandong University of Traditional Chinese MedicineJinanChina
| | - Xiang‐Qing Xu
- Department of NeurologyAffiliated Hospital of Shandong University of Traditional Chinese MedicineJinanChina
| | - He Li
- The First Clinical Medical CollegeShandong University of Traditional Chinese MedicineJinanChina
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Mroke P, Goit R, Rizwan M, Tariq S, Rizwan AW, Umer M, Nassar FF, Torijano Sarria AJ, Singh D, Baig I. Implications of the Gut Microbiome in Alzheimer's Disease: A Narrative Review. Cureus 2024; 16:e73681. [PMID: 39677207 PMCID: PMC11646158 DOI: 10.7759/cureus.73681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2024] [Indexed: 12/17/2024] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder, with its prevalence doubling approximately every decade. It is a significant contributor to disability-adjusted life-years in individuals aged 50 and older, impacting a substantial portion of this population globally. The pathophysiology of AD is primarily explained by two hypotheses: the amyloid cascade hypothesis and the tau hypothesis. While the amyloid cascade hypothesis is widely accepted as the main contributor to AD, both mechanisms promote neuroinflammation by driving the formation of amyloid-beta (Aβ) plaques and tau tangles, which are key features of the neurodegenerative process. Recent studies highlight the critical role of the gut microbiome (GMB) in the progression of AD. Gut dysbiosis has been linked to neuroinflammation, altered Aβ metabolism, blood-brain barrier disruption, and changes in neuroactive metabolites. Targeting the GMB offers potential therapeutic avenues aimed at restoring microbial balance and mitigating the effects of dysbiosis. The gut-brain axis, crucial for neurological health, remains underexplored in AD, especially since current research is limited to animal models and small human studies, leaving uncertainty about specific gut bacteria's roles in AD. Currently, pharmacological treatments for AD include cholinesterase inhibitors and memantine. This review discusses newer and emerging treatments targeting Aβ and tau pathology, alongside microbiome-based interventions. Larger, human-based studies with diverse populations are essential to establish the therapeutic efficacy of these microbiome-targeted treatments and their long-term impact on AD management.
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Affiliation(s)
- Palvi Mroke
- Internal Medicine, Caribbean Medical University School of Medicine, Willemstad, CUW
| | - Raman Goit
- Internal Medicine, Virgen Milagrosa University Foundation, San Carlos City, PHL
| | - Muhammad Rizwan
- Internal Medicine, Sheikh Zayed Medical College, Rahim Yar Khan, PAK
| | - Saba Tariq
- Internal Medicine, Amna Inayat Medical College Pakistan, Lahore, PAK
| | | | - Muhammad Umer
- Internal Medicine, King Edward Medical University, Lahore, PAK
| | - Fariha F Nassar
- Internal Medicine, Rajiv Gandhi University of Health Science, Bangalore, IND
| | | | - Dilpreet Singh
- Internal Medicine, Ascension St. John Hospital, Detroit, USA
| | - Imran Baig
- Internal Medicine, Houston Methodist Hospital, Houston, USA
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Zhang S, Lu J, Jin Z, Xu H, Zhang D, Chen J, Wang J. Gut microbiota metabolites: potential therapeutic targets for Alzheimer's disease? Front Pharmacol 2024; 15:1459655. [PMID: 39355779 PMCID: PMC11442227 DOI: 10.3389/fphar.2024.1459655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2024] [Accepted: 09/05/2024] [Indexed: 10/03/2024] Open
Abstract
Background Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive decline in cognitive function, which significantly increases pain and social burden. However, few therapeutic interventions are effective in preventing or mitigating the progression of AD. An increasing number of recent studies support the hypothesis that the gut microbiome and its metabolites may be associated with upstream regulators of AD pathology. Methods In this review, we comprehensively explore the potential mechanisms and currently available interventions targeting the microbiome for the improvement of AD. Our discussion is structured around modern research advancements in AD, the bidirectional communication between the gut and brain, the multi-target regulatory effects of microbial metabolites on AD, and therapeutic strategies aimed at modulating gut microbiota to manage AD. Results The gut microbiota plays a crucial role in the pathogenesis of AD through continuous bidirectional communication via the microbiota-gut-brain axis. Among these, microbial metabolites such as lipids, amino acids, bile acids and neurotransmitters, especially sphingolipids and phospholipids, may serve as central components of the gut-brain axis, regulating AD-related pathogenic mechanisms including β-amyloid metabolism, Tau protein phosphorylation, and neuroinflammation. Additionally, interventions such as probiotic administration, fecal microbiota transplantation, and antibiotic use have also provided evidence supporting the association between gut microbiota and AD. At the same time, we propose an innovative strategy for treating AD: a healthy lifestyle combined with targeted probiotics and other potential therapeutic interventions, aiming to restore intestinal ecology and microbiota balance. Conclusion Despite previous efforts, the molecular mechanisms by which gut microbes act on AD have yet to be fully described. However, intestinal microorganisms may become an essential target for connecting the gut-brain axis and improving the symptoms of AD. At the same time, it requires joint exploration by multiple centers and multiple disciplines.
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Affiliation(s)
- Shanshan Zhang
- The School to Changchun University of Chinese Medicine, Changchun, China
| | - Jing Lu
- Research Center of Traditional Chinese Medicine, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Ziqi Jin
- The School to Changchun University of Chinese Medicine, Changchun, China
| | - Hanying Xu
- Department of Encephalopathy, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Dongmei Zhang
- Research Center of Traditional Chinese Medicine, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Jianan Chen
- The School to Changchun University of Chinese Medicine, Changchun, China
| | - Jian Wang
- Department of Encephalopathy, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
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Agarwal N, Fan A, Huang X, Dehkharghani S, van der Kolk A. ISMRM Clinical Focus Meeting 2023: "Imaging the Fire in the Brain". J Magn Reson Imaging 2024. [PMID: 39193867 DOI: 10.1002/jmri.29587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 08/09/2024] [Accepted: 08/11/2024] [Indexed: 08/29/2024] Open
Abstract
Set during the Annual Meeting of the International Society for Magnetic Resonance in Medicine (ISMRM), the "Clinical Focus Meeting" (CFM) aims to bridge the gap between innovative magnetic resonance imaging (MRI) scientific research and daily patient care. This initiative is dedicated to maximizing the impact of MRI technology on healthcare outcomes for patients. At the 2023 Annual Meeting, clinicians and scientists from across the globe were invited to discuss neuroinflammation from various angles (entitled "Imaging the Fire in the Brain"). Topics ranged from fundamental mechanisms and biomarkers of neuroinflammation to the role of different contrast mechanisms, including both proton and non-proton techniques, in brain tumors, autoimmune disorders, and pediatric neuroinflammatory diseases. Discussions also delved into how systemic inflammation can trigger neuroinflammation and the role of the gut-brain axis in causing brain inflammation. Neuroinflammation arises from various external and internal factors and serves as a vital mechanism to mitigate tissue damage and provide neuroprotection. Nonetheless, excessive neuroinflammatory responses can lead to significant tissue injury and subsequent neurological impairments. Prolonged neuroinflammation can result in cellular apoptosis and neurodegeneration, posing severe consequences. MRI can be used to visualize these consequences, by detecting blood-brain barrier damage, characterizing brain lesions, quantifying edema, and identifying specific metabolites. It also facilitates monitoring of chronic changes in both the brain and spinal cord over time, potentially leading to better patient outcomes. This paper represents a summary of the 2023 CFM, and is intended to guide the enthusiastic MR user to several key and novel sequences that MRI offers to image pathophysiologic processes underlying acute and chronic neuroinflammation. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 3.
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Affiliation(s)
- Nivedita Agarwal
- Diagnostic Imaging and Neuroradiology Unit, IRCCS Scientific Institute E. Medea, Bosisio Parini, Lecco, Italy
| | - Audrey Fan
- Department of Neurology, University of California Davis Health, Sacramento, California, USA
- Department of Biomedical Engineering, University of California Davis, Davis, California, USA
| | - Xiaoqi Huang
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu, China
| | - Seena Dehkharghani
- Department of Radiology, Albert Einstein College of Medicine-Montefiore Health, New York, New York, USA
| | - Anja van der Kolk
- Department of Medical Imaging, Radboudumc, Nijmegen, The Netherlands
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Liang Y, Liu C, Cheng M, Geng L, Li J, Du W, Song M, Chen N, Yeleen TAN, Song L, Wang X, Han Y, Sheng C. The link between gut microbiome and Alzheimer's disease: From the perspective of new revised criteria for diagnosis and staging of Alzheimer's disease. Alzheimers Dement 2024; 20:5771-5788. [PMID: 38940631 PMCID: PMC11350031 DOI: 10.1002/alz.14057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/20/2024] [Accepted: 05/22/2024] [Indexed: 06/29/2024]
Abstract
Over the past decades, accumulating evidence suggests that the gut microbiome exerts a key role in Alzheimer's disease (AD). The Alzheimer's Association Workgroup is updating the diagnostic criteria for AD, which changed the profiles and categorization of biomarkers from "AT(N)" to "ATNIVS." Previously, most of studies focus on the correlation between the gut microbiome and amyloid beta deposition ("A"), the initial AD pathological feature triggering the "downstream" tauopathy and neurodegeneration. However, limited research investigated the interactions between the gut microbiome and other AD pathogenesis ("TNIVS"). In this review, we summarize current findings of the gut microbial characteristics in the whole spectrum of AD. Then, we describe the association of the gut microbiome with updated biomarker categories of AD pathogenesis. In addition, we outline the gut microbiome-related therapeutic strategies for AD. Finally, we discuss current key issues of the gut microbiome research in the AD field and future research directions. HIGHLIGHTS: The new revised criteria for Alzheimer's disease (AD) proposed by the Alzheimer's Association Workgroup have updated the profiles and categorization of biomarkers from "AT(N)" to "ATNIVS." The associations of the gut microbiome with updated biomarker categories of AD pathogenesis are described. Current findings of the gut microbial characteristics in the whole spectrum of AD are summarized. Therapeutic strategies for AD based on the gut microbiome are proposed.
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Affiliation(s)
- Yuan Liang
- Department of NeurologyThe Affiliated Hospital of Jining Medical UniversityJiningChina
| | - Congcong Liu
- Department of NeurologyThe Affiliated Hospital of Jining Medical UniversityJiningChina
| | - Manman Cheng
- Department of Respiratory MedicineThe Affiliated Hospital of Jining Medical UniversityJiningChina
| | - Lijie Geng
- Department of RadiologyThe People's Hospital of YanzhouJiningChina
| | - Jing Li
- Department of EmergencyThe Affiliated Hospital of Jining Medical UniversityJiningChina
| | - Wenying Du
- Department of NeurologyChina‐Japan Friendship HospitalBeijingChina
| | - Minfang Song
- Department of NeurologyThe Affiliated Hospital of Jining Medical UniversityJiningChina
| | - Nian Chen
- Department of NeurologyThe Affiliated Hospital of Jining Medical UniversityJiningChina
| | | | - Li Song
- Department of NeurologyThe Affiliated Hospital of Jining Medical UniversityJiningChina
| | - Xiaoni Wang
- Department of NeurologySir Run Shaw HospitalSchool of MedicineZhejiang UniversityHangzhouChina
| | - Ying Han
- Department of NeurologyXuanwu Hospital of Capital Medical UniversityBeijingChina
- Key Laboratory of Biomedical Engineering of Hainan ProvinceSchool of Biomedical EngineeringHainan UniversityHaikouChina
- Center of Alzheimer's DiseaseBeijing Institute for Brain DisordersBeijingChina
- National Clinical Research Center for Geriatric DisordersBeijingChina
| | - Can Sheng
- Department of NeurologyThe Affiliated Hospital of Jining Medical UniversityJiningChina
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Ullah H, Arbab S, Tian Y, Chen Y, Liu CQ, Li Q, Li K. Crosstalk between gut microbiota and host immune system and its response to traumatic injury. Front Immunol 2024; 15:1413485. [PMID: 39144142 PMCID: PMC11321976 DOI: 10.3389/fimmu.2024.1413485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Accepted: 06/04/2024] [Indexed: 08/16/2024] Open
Abstract
Millions of microorganisms make up the complex microbial ecosystem found in the human gut. The immune system's interaction with the gut microbiota is essential for preventing inflammation and maintaining intestinal homeostasis. Numerous metabolic products that can cross-talk between immune cells and the gut epithelium are metabolized by the gut microbiota. Traumatic injury elicits a great and multifaceted immune response in the minutes after the initial offense, containing simultaneous pro- and anti-inflammatory responses. The development of innovative therapies that improve patient outcomes depends on the gut microbiota and immunological responses to trauma. The altered makeup of gut microbes, or gut dysbiosis, can also dysregulate immunological responses, resulting in inflammation. Major human diseases may become more common as a result of chronic dysbiosis and the translocation of bacteria and the products of their metabolism beyond the mucosal barrier. In this review, we briefly summarize the interactions between the gut microbiota and the immune system and human disease and their therapeutic probiotic formulations. We also discuss the immune response to traumatic injury.
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Affiliation(s)
- Hanif Ullah
- Medicine and Engineering Interdisciplinary Research Laboratory of Nursing & Materials/Nursing Key Laboratory of Sichuan Province, West China Hospital, Sichuan University/West China School of Nursing, Sichuan University, Chengdu, Sichuan, China
| | - Safia Arbab
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Yali Tian
- Medicine and Engineering Interdisciplinary Research Laboratory of Nursing & Materials/Nursing Key Laboratory of Sichuan Province, West China Hospital, Sichuan University/West China School of Nursing, Sichuan University, Chengdu, Sichuan, China
| | - Yuwen Chen
- Medicine and Engineering Interdisciplinary Research Laboratory of Nursing & Materials/Nursing Key Laboratory of Sichuan Province, West China Hospital, Sichuan University/West China School of Nursing, Sichuan University, Chengdu, Sichuan, China
| | - Chang-qing Liu
- Medicine and Engineering Interdisciplinary Research Laboratory of Nursing & Materials/Nursing Key Laboratory of Sichuan Province, West China Hospital, Sichuan University/West China School of Nursing, Sichuan University, Chengdu, Sichuan, China
| | - Qijie Li
- Medicine and Engineering Interdisciplinary Research Laboratory of Nursing & Materials/Nursing Key Laboratory of Sichuan Province, West China Hospital, Sichuan University/West China School of Nursing, Sichuan University, Chengdu, Sichuan, China
| | - Ka Li
- Medicine and Engineering Interdisciplinary Research Laboratory of Nursing & Materials/Nursing Key Laboratory of Sichuan Province, West China Hospital, Sichuan University/West China School of Nursing, Sichuan University, Chengdu, Sichuan, China
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Wadop YN, Vasquez EL, Mathews JJ, Muhammad JAS, Mavarez RP, Satizabal C, Gonzales MM, Tanner J, Maestre G, Fonteh AN, Seshadri S, Kautz TF, Fongang B. Differential Patterns of Gut and Oral Microbiomes in Hispanic Individuals with Cognitive Impairment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.27.605455. [PMID: 39211240 PMCID: PMC11361189 DOI: 10.1101/2024.07.27.605455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Alzheimer's disease and related dementias (ADRD) have been associated with alterations in both oral and gut microbiomes. While extensive research has focused on the role of gut dysbiosis in ADRD, the contribution of the oral microbiome remains relatively understudied. Furthermore, the potential synergistic interactions between oral and gut microbiomes in ADRD pathology are largely unexplored. This study aims to evaluate distinct patterns and potential synergistic effects of oral and gut microbiomes in a cohort of predominantly Hispanic individuals with cognitive impairment (CI) and without cognitive impairment (NC). We conducted 16S rRNA gene sequencing on stool and saliva samples from 32 participants (17 CI, 15 NC; 62.5% female, mean age = 70.4 ± 6.2 years) recruited in San Antonio, Texas, USA. Correlation analysis through MaAslin2 assessed the relationship between participants' clinical measurements (e.g., fasting glucose and blood cholesterol) and their gut and saliva microbial contents. Differential abundance analysis evaluated taxa with significant differences between CI and NC groups, and alpha and beta diversity metrics assessed within-sample and group compositional differences. Our analyses revealed no significant differences between NC and CI groups in fasting glucose or blood cholesterol levels. However, a clear association was observed between gut microbiome composition and levels of fasting glucose and blood cholesterol. While alpha and beta diversity metrics showed no significant differences between CI and NC groups, differential abundance analysis revealed an increased presence of oral genera such as Dialister , Fretibacterium , and Mycoplasma in CI participants. Conversely, CI individuals exhibited a decreased abundance of gut genera, including Shuttleworthia , Holdemania , and Subdoligranulum , which are known for their anti-inflammatory properties. No evidence was found for synergistic contributions between oral and gut microbiomes in the context of ADRD. Our findings suggest that similar to the gut microbiome, the oral microbiome undergoes significant modifications as individuals transition from NC to CI. Notably, the identified oral microbes have been previously associated with periodontal diseases and gingivitis. These results underscore the necessity for further investigations with larger sample sizes to validate our findings and elucidate the complex interplay between oral and gut microbiomes in ADRD pathogenesis.
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He J, Cabrera-Mendoza B, Friligkou E, Mecca AP, van Dyck CH, Pathak GA, Polimanti R. Sex differences in the associations of socioeconomic factors and cognitive performance with family history of Alzheimer's disease. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.06.12.24308850. [PMID: 38947007 PMCID: PMC11213115 DOI: 10.1101/2024.06.12.24308850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
INTRODUCTION While higher socioeconomic factors (SEF) and cognitive performance (CP) have been associated with reduced Alzheimer's disease (AD) risk, recent evidence highlighted that these factors may have opposite effects on family history of AD (FHAD). METHODS Leveraging data from the UK Biobank (N=448,100) and the All of Us Research Program (N=240,319), we applied generalized linear regression models, polygenic risk scoring (PRS), and one-sample Mendelian randomization (MR) to test the sex-specific SEF and CP associations with AD and FHAD. RESULTS Observational and genetically informed analyses highlighted that higher SEF and CP were associated with reduced AD and sibling-FHAD, while these factors were associated with increased parent-FHAD. We also observed that population minorities may present different patterns with respect to sibling-FHAD vs. parent-FHAD. Sex differences in FHAD associations were identified in ancestry-specific and SEF PRS and MR results. DISCUSSION This study contributes to understanding the sex-specific relationships linking SEF and CP to FHAD, highlighting the potential role of reporting, recall, and surviving-related dynamics.
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Paprzycka O, Wieczorek J, Nowak I, Madej M, Strzalka-Mrozik B. Potential Application of MicroRNAs and Some Other Molecular Biomarkers in Alzheimer's Disease. Curr Issues Mol Biol 2024; 46:5066-5084. [PMID: 38920976 PMCID: PMC11202417 DOI: 10.3390/cimb46060304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Revised: 05/05/2024] [Accepted: 05/21/2024] [Indexed: 06/27/2024] Open
Abstract
Alzheimer's disease (AD) is the world's most common neurodegenerative disease, expected to affect up to one-third of the elderly population in the near future. Among the major challenges in combating AD are the inability to reverse the damage caused by the disease, expensive diagnostic tools, and the lack of specific markers for the early detection of AD. This paper highlights promising research directions for molecular markers in AD diagnosis, including the diagnostic potential of microRNAs. The latest molecular methods for diagnosing AD are discussed, with particular emphasis on diagnostic techniques prior to the appearance of full AD symptoms and markers detectable in human body fluids. A collection of recent studies demonstrates the promising potential of molecular methods in AD diagnosis, using miRNAs as biomarkers. Up- or downregulation in neurodegenerative diseases may not only provide a new diagnostic tool but also serve as a marker for differentiating neurodegenerative diseases. However, further research in this direction is needed.
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Affiliation(s)
- Olga Paprzycka
- Department of Molecular Biology, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia, 40-055 Katowice, Poland; (O.P.); (J.W.); (M.M.)
| | - Jan Wieczorek
- Department of Molecular Biology, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia, 40-055 Katowice, Poland; (O.P.); (J.W.); (M.M.)
| | - Ilona Nowak
- Silesia LabMed, Centre for Research and Implementation, Medical University of Silesia, 40-752 Katowice, Poland;
| | - Marcel Madej
- Department of Molecular Biology, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia, 40-055 Katowice, Poland; (O.P.); (J.W.); (M.M.)
- Silesia LabMed, Centre for Research and Implementation, Medical University of Silesia, 40-752 Katowice, Poland;
| | - Barbara Strzalka-Mrozik
- Department of Molecular Biology, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia, 40-055 Katowice, Poland; (O.P.); (J.W.); (M.M.)
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Peddinti V, Avaghade MM, Suthar SU, Rout B, Gomte SS, Agnihotri TG, Jain A. Gut instincts: Unveiling the connection between gut microbiota and Alzheimer's disease. Clin Nutr ESPEN 2024; 60:266-280. [PMID: 38479921 DOI: 10.1016/j.clnesp.2024.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 02/16/2024] [Indexed: 04/13/2024]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder marked by neuroinflammation and gradual cognitive decline. Recent research has revealed that the gut microbiota (GM) plays an important role in the pathogenesis of AD through the microbiota-gut-brain axis. However, the mechanism by which GM and microbial metabolites alter brain function is not clearly understood. GM dysbiosis increases the permeability of the intestine, alters the blood-brain barrier permeability, and elevates proinflammatory mediators causing neurodegeneration. This review article introduced us to the composition and functions of GM along with its repercussions of dysbiosis in relation to AD. We also discussed the importance of the gut-brain axis and its role in communication. Later we focused on the mechanism behind gut dysbiosis and the progression of AD including neuroinflammation, oxidative stress, and changes in neurotransmitter levels. Furthermore, we highlighted recent developments in AD management, such as microbiota-based therapy, dietary interventions like prebiotics, probiotics, and fecal microbiota transplantation. Finally, we concluded with challenges and future directions in AD research based on GM.
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Affiliation(s)
- Vasu Peddinti
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Palaj, Gandhinagar, 382355, Gujarat, India
| | - Manoj Mohan Avaghade
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Palaj, Gandhinagar, 382355, Gujarat, India
| | - Sunil Umedmal Suthar
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Palaj, Gandhinagar, 382355, Gujarat, India
| | - Biswajit Rout
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Palaj, Gandhinagar, 382355, Gujarat, India
| | - Shyam Sudhakar Gomte
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Palaj, Gandhinagar, 382355, Gujarat, India
| | - Tejas Girish Agnihotri
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Palaj, Gandhinagar, 382355, Gujarat, India
| | - Aakanchha Jain
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Palaj, Gandhinagar, 382355, Gujarat, India.
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13
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Yang K, Zhang Z, Zhang Q, Zhang H, Liu X, Jia Z, Ying Z, Liu W. Potential diagnostic markers and therapeutic targets for periodontitis and Alzheimer's disease based on bioinformatics analysis. J Periodontal Res 2024; 59:366-380. [PMID: 38189472 DOI: 10.1111/jre.13220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 11/02/2023] [Accepted: 11/22/2023] [Indexed: 01/09/2024]
Abstract
BACKGROUND AND OBJECTIVE As a chronic inflammatory disease, periodontitis threatens oral health and is a risk factor for Alzheimer's disease (AD). There is growing evidence that these two diseases are closely related. However, current research is still incomplete in understanding the common genes and common mechanisms between periodontitis and AD. In this study, we aimed to identify common genes in periodontitis and AD and analyze the relationship between crucial genes and immune cells to provide new therapeutic targets for clinical treatment. MATERIALS AND METHODS We evaluated differentially expressed genes (DEGs) specific to periodontitis and AD. Co-expressed genes were identified by obtaining gene expression profile data from the Gene Expression Omnibus (GEO) database. Using the STRING database, protein-protein interaction (PPI) networks were constructed, and essential genes were identified. We also used four algorithms to identify critical genes and constructed regulatory networks. The association of crucial genes with immune cells and potential therapeutic effects was also assessed. RESULTS PDGFRB, VCAN, TIMP1, CHL1, EFEMP2, and IGFBP5 were obtained as crucial common genes. Immune infiltration analysis showed that Natural killer cells and Myeloid-derived suppressor cells were significantly differentially expressed in patients with PD and AD compared with the normal group. FOXC1 and GATA2 are important TFs for PD and AD. MiR-23a, miR-23b, miR-23a, and miR-23b were associated with AD and PD. Finally, the hub genes retrieved from the DSigDB database indicate multiple drug molecule and drug-target interactions. CONCLUSION This study reveals commonalities in common hub genes and immune infiltration between periodontitis and AD, and the analysis of six hub genes and immune cells may provide new insights into potential therapeutic directions for the pathogenesis of periodontitis complicated by AD.
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Affiliation(s)
- Kai Yang
- Acupuncture and Moxibustion Massage College, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Zhaoqi Zhang
- The First Clinical Medical College of Shandong University of Chinese Medicine, Jinan, China
| | - Qingyuan Zhang
- The First Clinical Medical College of Shandong University of Chinese Medicine, Jinan, China
| | - Hongyu Zhang
- Rehabilitation Department, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Xiaoju Liu
- The First Clinical Medical College of Shandong University of Chinese Medicine, Jinan, China
| | - Zhicheng Jia
- The First Clinical Medical College of Shandong University of Chinese Medicine, Jinan, China
| | - Zhenhao Ying
- Rehabilitation Department, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Wei Liu
- Department of Neurology, The Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
- Shandong University of Traditional Chinese Medicine, Jinan, China
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14
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Hofford RS, Kiraly DD. Clinical and Preclinical Evidence for Gut Microbiome Mechanisms in Substance Use Disorders. Biol Psychiatry 2024; 95:329-338. [PMID: 37573004 PMCID: PMC10884738 DOI: 10.1016/j.biopsych.2023.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 08/01/2023] [Accepted: 08/04/2023] [Indexed: 08/14/2023]
Abstract
Substance use disorders are a set of recalcitrant neuropsychiatric conditions that cause tremendous morbidity and mortality and are among the leading causes of loss of disability-adjusted life years worldwide. While each specific substance use disorder is driven by problematic use of a different substance, they all share a similar pattern of escalating and out-of-control substance use, continued use despite negative consequences, and a remitting/relapsing pattern over time. Despite significant advances in our understanding of the neurobiology of these conditions, current treatment options remain few and are ineffective for too many individuals. In recent years, there has been a rapidly growing body of literature demonstrating that the resident population of microbes in the gastrointestinal tract, collectively called the gut microbiome, plays an important role in modulating brain and behavior in preclinical and clinical studies of psychiatric disease. While these findings have not yet been translated into clinical practice, this remains an important and exciting avenue for translational research. In this review, we highlight the current state of microbiome-brain research within the substance use field with a focus on both clinical and preclinical studies. We also discuss potential neurobiological mechanisms underlying microbiome effects on models of substance use disorder and propose future directions to bring these findings from bench to bedside.
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Affiliation(s)
- Rebecca S Hofford
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Atrium Health Wake Forest Baptist, Winston-Salem, North Carolina
| | - Drew D Kiraly
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Atrium Health Wake Forest Baptist, Winston-Salem, North Carolina; Department of Psychiatry, Wake Forest University School of Medicine, Atrium Health Wake Forest Baptist, Winston-Salem, North Carolina.
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15
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Ragavan ML, Hemalatha S. The functional roles of short chain fatty acids as postbiotics in human gut: future perspectives. Food Sci Biotechnol 2024; 33:275-285. [PMID: 38222911 PMCID: PMC10786766 DOI: 10.1007/s10068-023-01414-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/26/2023] [Accepted: 08/07/2023] [Indexed: 01/16/2024] Open
Abstract
The significance of gut microbiome and their metabolites (postbiotics) on human health could be a promising approach to treat various diseases that includes inflammatory bowel diseases, colon cancer, and many neurological disorders. Probiotics with potential mental health benefits (psychobiotics) can alter the gut-brain axis via immunological, humoral, neuronal, and metabolic pathways. Recently, probiotic bacteria like Lactobacillus and Bifidobacterium have been demonstrated for SCFAs production, which play a crucial role in a variety of diseases. These acids could enhance the production of mucins, antimicrobial proteins (bacteriocins and peptides), cytokines (Interleukin 10 and 18) and neurotransmitters (serotonin) in the intestine to main the gut microbiota, intestinal barrier system and other immune functions. In this review, we discuss about two mechanisms such as (i) SCFAs mediated intestinal barrier system, and (ii) SCFAs mediated gut-brain axis to elucidate the therapeutic options for the treatment/prevention of various diseases.
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Affiliation(s)
| | - S. Hemalatha
- School of Life Sciences, BSACIST, Vandalur, Chennai, Tamil Nadu India
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16
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Pappolla MA, Martins RN, Poeggeler B, Omar RA, Perry G. Oxidative Stress in Alzheimer's Disease: The Shortcomings of Antioxidant Therapies. J Alzheimers Dis 2024; 101:S155-S178. [PMID: 39422961 DOI: 10.3233/jad-240659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2024]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by gradual and progressive cognitive decline leading to dementia. At its core, the neuropathological features of AD include hallmark accumulations of amyloid-β and hyperphosphorylated tau proteins. Other harmful processes, such as oxidative stress and inflammation, contribute to the disease's neuropathological progression. This review evaluates the role of oxidative stress in AD, placing a spotlight on the disappointing outcomes of various antioxidant clinical trials. Several hypotheses are discussed that might elucidate the failures of these therapies in AD. Specifically: 1) The paradoxical and overlooked harmful implications of prooxidant intermediates, particularly stemming from conventional antioxidants like vitamins E and C; 2) The challenges and failure to appreciate the issue of bioavailability-epitomized by the dictum "no on-site protection, no protection"-and the preeminent, yet often ignored, role played by endogenous antioxidant enzymes in combating oxidative stress; 3) The influence of unrecognized etiologies, such as latent infectious agents and others, as foundational drivers of oxidative stress in AD; 4) The underestimation of the complexity of oxidative mechanisms and the necessity of multi-targeted therapeutic approaches, such as those provided by various diets; and 5) The limitations of clinical trial designs in fully capturing the effects of antioxidants on AD progression. This article also examines the outcomes of select clinical trials while highlighting the challenges and barriers these therapies pose, offering insights into potential mechanisms to overcome their marginal success.
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Affiliation(s)
- Miguel A Pappolla
- Department of Neurology, University of Texas Medical Branch, Galveston, TX, USA
| | - Ralph N Martins
- Aging and Alzheimer's Disease Centre, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
| | - Burkhard Poeggeler
- Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, Faculty of Biology and Psychology, Georg August University, Gottingen, Germany
| | - Rawhi A Omar
- Department of Pathology, University of Louisville, Louisville, KY, USA
| | - George Perry
- Department of Neuroscience, Developmental and Regenerative Biology, University of Texas at San Antonio, San Antonio, TX, USA
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17
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Simão DO, Vieira VS, Tosatti JAG, Gomes KB. Lipids, Gut Microbiota, and the Complex Relationship with Alzheimer's Disease: A Narrative Review. Nutrients 2023; 15:4661. [PMID: 37960314 PMCID: PMC10649859 DOI: 10.3390/nu15214661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/28/2023] [Accepted: 11/01/2023] [Indexed: 11/15/2023] Open
Abstract
Alzheimer's Disease (AD) is a multifactorial, progressive, and chronic neurodegenerative disorder associated with the aging process. Memory deficits, cognitive impairment, and motor dysfunction are characteristics of AD. It is estimated that, by 2050, 131.5 million people will have AD. There is evidence that the gastrointestinal microbiome and diet may contribute to the development of AD or act preventively. Communication between the brain and the intestine occurs through immune cells in the mucosa and endocrine cells, or via the vagus nerve. Aging promotes intestinal dysbiosis, characterized by an increase in pro-inflammatory pathogenic bacteria and a reduction in anti-inflammatory response-mediating bacteria, thus contributing to neuroinflammation and neuronal damage, ultimately leading to cognitive decline. Therefore, the microbiota-gut-brain axis has a significant impact on neurodegenerative disorders. Lipids may play a preventive or contributory role in the development of AD. High consumption of saturated and trans fats can increase cortisol release and lead to other chronic diseases associated with AD. Conversely, low levels of omega-3 polyunsaturated fatty acids may be linked to neurodegenerative diseases. Unlike other studies, this review aims to describe, in an integrative way, the interaction between the gastrointestinal microbiome, lipids, and AD, providing valuable insights into how the relationship between these factors affects disease progression, contributing to prevention and treatment strategies.
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Affiliation(s)
- Daiane Oliveira Simão
- Faculty of Medicine, Federal University of Minas Gerais, Professor Alfredo Balena Avenue, 190, Santa Efigênia, Belo Horizonte 30130-100, MG, Brazil;
| | - Vitoria Silva Vieira
- Department of Nutrition, School of Nursing, Federal University of Minas Gerais, Professor Alfredo Balena Avenue, 190, Santa Efigênia, Belo Horizonte 30130-100, MG, Brazil;
| | - Jéssica Abdo Gonçalves Tosatti
- Department of Clinical and Toxicological Analyzes, Faculty of Pharmacy, Federal University of Minas Gerais, Presidente Antônio Carlos Avenue, 6627, Pampulha, Belo Horizonte 31270-901, MG, Brazil;
| | - Karina Braga Gomes
- Faculty of Medicine, Federal University of Minas Gerais, Professor Alfredo Balena Avenue, 190, Santa Efigênia, Belo Horizonte 30130-100, MG, Brazil;
- Department of Clinical and Toxicological Analyzes, Faculty of Pharmacy, Federal University of Minas Gerais, Presidente Antônio Carlos Avenue, 6627, Pampulha, Belo Horizonte 31270-901, MG, Brazil;
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18
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Thakkar A, Vora A, Kaur G, Akhtar J. Dysbiosis and Alzheimer's disease: role of probiotics, prebiotics and synbiotics. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2023; 396:2911-2923. [PMID: 37284896 DOI: 10.1007/s00210-023-02554-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 05/26/2023] [Indexed: 06/08/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease characterized by dementia and the accumulation of amyloid beta in the brain. Recently, microbial dysbiosis has been identified as one of the major factors involved in the onset and progression of AD. Imbalance in gut microbiota is known to affect central nervous system (CNS) functions through the gut-brain axis and involves inflammatory, immune, neuroendocrine and metabolic pathways. An altered gut microbiome is known to affect the gut and BBB permeability, resulting in imbalance in levels of neurotransmitters and neuroactive peptides/factors. Restoration of levels of beneficial microorganisms in the gut has demonstrated promising effects in AD in pre-clinical and clinical studies. The current review enlists the important beneficial microbial species present in the gut, the effect of their metabolites on CNS, mechanisms involved in dysbiosis related to AD and the beneficial effects of probiotics on AD. It also highlights challenges involved in large-scale manufacturing and quality control of probiotic formulations.
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Affiliation(s)
- Ami Thakkar
- Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, Shri Vile Parle Kelavani Mandal's Narsee Monjee Institute of Management Studies, Mumbai, India
| | - Amisha Vora
- Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, Shri Vile Parle Kelavani Mandal's Narsee Monjee Institute of Management Studies, Mumbai, India.
| | - Ginpreet Kaur
- Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, Shri Vile Parle Kelavani Mandal's Narsee Monjee Institute of Management Studies, Mumbai, India
| | - Jamal Akhtar
- Central Council for Research in Unani Medicine, Ministry of AYUSH, New Delhi, India
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19
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Ullah H, Arbab S, Tian Y, Liu CQ, Chen Y, Qijie L, Khan MIU, Hassan IU, Li K. The gut microbiota-brain axis in neurological disorder. Front Neurosci 2023; 17:1225875. [PMID: 37600019 PMCID: PMC10436500 DOI: 10.3389/fnins.2023.1225875] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 07/07/2023] [Indexed: 08/22/2023] Open
Abstract
The gut microbiota (GM) plays an important role in the physiology and pathology of the host. Microbiota communicate with different organs of the organism by synthesizing hormones and regulating body activity. The interaction of the central nervous system (CNS) and gut signaling pathways includes chemical, neural immune and endocrine routes. Alteration or dysbiosis in the gut microbiota leads to different gastrointestinal tract disorders that ultimately impact host physiology because of the abnormal microbial metabolites that stimulate and trigger different physiologic reactions in the host body. Intestinal dysbiosis leads to a change in the bidirectional relationship between the CNS and GM, which is linked to the pathogenesis of neurodevelopmental and neurological disorders. Increasing preclinical and clinical studies/evidence indicate that gut microbes are a possible susceptibility factor for the progression of neurological disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS) and autism spectrum disorder (ASD). In this review, we discuss the crucial connection between the gut microbiota and the central nervous system, the signaling pathways of multiple biological systems and the contribution of gut microbiota-related neurological disorders.
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Affiliation(s)
- Hanif Ullah
- Department of Nursing, West China Hospital, West China School of Nursing, Sichuan University, Chengdu, China
| | - Safia Arbab
- Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture, Lanzhou, China
- Key Laboratory of New Animal Drug Project of Gansu Province, Lanzhou, China
- Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Yali Tian
- Department of Nursing, West China Hospital, West China School of Nursing, Sichuan University, Chengdu, China
| | - Chang-qing Liu
- Department of Nursing, West China Hospital, West China School of Nursing, Sichuan University, Chengdu, China
| | - Yuwen Chen
- Department of Nursing, West China Hospital, West China School of Nursing, Sichuan University, Chengdu, China
| | - Li Qijie
- Department of Nursing, West China Hospital, West China School of Nursing, Sichuan University, Chengdu, China
| | - Muhammad Inayat Ullah Khan
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Inam Ul Hassan
- Department of Microbiology, Hazara University Mansehra, Mansehra, Pakistan
| | - Ka Li
- Department of Nursing, West China Hospital, West China School of Nursing, Sichuan University, Chengdu, China
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20
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Guo X, Zhang X, Tang P, Chong L, Li R. Integration of genome-wide association studies (GWAS) and microbiome data highlights the impact of sulfate-reducing bacteria on Alzheimer's disease. Age Ageing 2023; 52:afad112. [PMID: 37466641 DOI: 10.1093/ageing/afad112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Indexed: 07/20/2023] Open
Abstract
BACKGROUND observational studies have indicated that gut microbiome dysbiosis was associated with Alzheimer's disease (ad). However, the results are largely inconsistent and it remains unknown whether the association is causal in nature. METHODS leveraging observational studies and genome-wide association studies (GWAS) on the gut microbiome in ad patients, we pooled the microbiome data (N = 1,109) to screen the microbiota significantly altered in ad patients and then conducted Mendelian randomisation (MR) study to determine the causal associations between altered microbiota (N = 18,340) and ad using two different ad GWAS datasets (N = 63,926 and N = 472,868) using the inverse variance-weighted (IVW) method. RESULTS the combined effect sizes from observational studies showed that 8 phyla, 18 classes, 22 orders, 37 families, 78 genera and 109 species significantly changed in ad patients. Using the MR analysis, we found that two classes, one order, one family and one genus were suggestively associated with ad consistently in two different GWAS datasets. Both observational studies and MR analysis simultaneously showed that Desulfovibrionales (order) and Desulfovibrionaceae (family), which were mainly implicated in dissimilatory sulfate reduction, were significantly associated with an elevated risk of ad. CONCLUSIONS our findings demonstrated that the abundance of sulfate-reducing bacteria was increased in ad patients, which was causally linked to an increased risk of ad. Further efforts are warranted to clarify the underlying mechanisms, which will provide new insight into the prevention and treatment of ad.
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Affiliation(s)
- Xingzhi Guo
- Department of Geriatric Neurology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, People's Republic of China
- Shaanxi Provincial Clinical Research Center for Geriatric Medicine, Xi'an Shaanxi 710068, People's Republic of China
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an Shaanxi 710072, People's Republic of China
| | - Xin Zhang
- Department of Geriatric Neurology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, People's Republic of China
- Shaanxi Provincial Clinical Research Center for Geriatric Medicine, Xi'an Shaanxi 710068, People's Republic of China
| | - Peng Tang
- Department of Geriatric Neurology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, People's Republic of China
- Shaanxi Provincial Clinical Research Center for Geriatric Medicine, Xi'an Shaanxi 710068, People's Republic of China
| | - Li Chong
- Department of Geriatric Neurology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, People's Republic of China
- Shaanxi Provincial Clinical Research Center for Geriatric Medicine, Xi'an Shaanxi 710068, People's Republic of China
| | - Rui Li
- Department of Geriatric Neurology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, People's Republic of China
- Shaanxi Provincial Clinical Research Center for Geriatric Medicine, Xi'an Shaanxi 710068, People's Republic of China
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an Shaanxi 710072, People's Republic of China
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21
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Hung CC, Crowe-White KM, McDonough IM. A seed and soil model of gut dysbiosis in Alzheimer's disease. Aging (Albany NY) 2023; 15:5235-5237. [PMID: 37338514 PMCID: PMC10333083 DOI: 10.18632/aging.204840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/17/2023] [Indexed: 06/21/2023]
Affiliation(s)
- Chun-Che Hung
- Department of Occupational Therapy and Graduate Institute of Behavioral Sciences, Chang Gung University, Taiwan
| | - Kristi M. Crowe-White
- Department of Human Nutrition and Hospitality Management, The University of Alabama, Tuscaloosa, AL 35487, USA
- Alabama Research Institute on Aging, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Ian M. McDonough
- Alabama Research Institute on Aging, The University of Alabama, Tuscaloosa, AL 35487, USA
- Department of Psychology, The University of Alabama, Tuscaloosa, AL 35487, USA
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22
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Yang J, Li J, Zhang X, Zhou Q, Wang J, Chen Q, Meng X, Xia Y. Effects of Ecologically Relevant Concentrations of Cadmium on the Microbiota, Short-Chain Fatty Acids, and FFAR 2 Expression in Zebrafish. Metabolites 2023; 13:metabo13050657. [PMID: 37233698 DOI: 10.3390/metabo13050657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/09/2023] [Accepted: 05/11/2023] [Indexed: 05/27/2023] Open
Abstract
Exposure to cadmium (Cd) can affect neurodevelopment and results in increased potential of developing neurodegenerative diseases during the early developmental stage of organisms, but the mechanisms through which exposure to environmentally relevant concentrations of Cd lead to developmental neurotoxicity remain unclear. Although we know that microbial community fixations overlap with the neurodevelopmental window during early development and that Cd-induced neurodevelopmental toxicity may be related to the disruption of microorganisms during early development, information on the effects of exposure to environmentally relevant Cd concentrations on gut microbiota disruption and neurodevelopment is scarce. Therefore, we established a model of zebrafish exposed to Cd (5 µg/L) to observe the changes in the gut microbiota, SCFAs, and free fatty acid receptor 2 (FFAR2) in zebrafish larvae exposed to Cd for 7 days. Our results indicated that there were significant changes in the gut microbial composition due to the exposure to Cd in zebrafish larvae. At the genus level, there were decreases in the relative abundances of Phascolarctobacterium, Candidatus Saccharimonas, and Blautia in the Cd group. Our analysis revealed that the acetic acid concentration was decreased (p > 0.05) while the isobutyric acid concentration was increased (p < 0.05). Further correlation analysis indicated a positive correlation between the content of acetic acid and the relative abundances of Phascolarctobacterium and Candidatus Saccharimonas (R = 0.842, p < 0.01; R = 0.767, p < 0.01), and a negative correlation between that of isobutyric acid and the relative abundance of Blautia glucerasea (R = -0.673, p < 0.05). FFAR2 needs to be activated by SCFAs to exert physiological effects, and acetic acid is its main ligand. The FFAR2 expression and the acetic acid concentration were decreased in the Cd group. We speculate that FFAR2 may be implicated in the regulatory mechanism of the gut-brain axis in Cd-induced neurodevelopmental toxicity.
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Affiliation(s)
- Jian Yang
- School of Public Health, Guangdong Pharmaceutical University, 283, Jianghaidadao, Guangzhou 510006, China
| | - Junyi Li
- School of Public Health, Guangdong Pharmaceutical University, 283, Jianghaidadao, Guangzhou 510006, China
| | - Xiaoshun Zhang
- Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Occupational Health and Occupational Medicine, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Qin Zhou
- Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Occupational Health and Occupational Medicine, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Junyi Wang
- School of Public Health, Guangdong Pharmaceutical University, 283, Jianghaidadao, Guangzhou 510006, China
| | - Qingsong Chen
- School of Public Health, Guangdong Pharmaceutical University, 283, Jianghaidadao, Guangzhou 510006, China
| | - Xiaojing Meng
- Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Occupational Health and Occupational Medicine, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Yuan Xia
- School of Public Health, Guangdong Pharmaceutical University, 283, Jianghaidadao, Guangzhou 510006, China
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23
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Fu J, Li J, Sun Y, Liu S, Song F, Liu Z. In-depth investigation of the mechanisms of Schisandra chinensis polysaccharide mitigating Alzheimer's disease rat via gut microbiota and feces metabolomics. Int J Biol Macromol 2023; 232:123488. [PMID: 36731694 DOI: 10.1016/j.ijbiomac.2023.123488] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 12/24/2022] [Accepted: 01/26/2023] [Indexed: 02/01/2023]
Abstract
Schisandra chinensis (S. chinensis) is an herbal medicine used for the treatment of Alzheimer's disease (AD). The purified polysaccharide fraction, namely SCP2, was previously isolated from S. chinensis crude polysaccharide (SCP) and its structure and in vitro activity were investigated. However, the in vivo activity of SCP2 and its potential mechanism for the treatment of AD have yet to be determined. This study used a combination of microbiomics and metabolomics to comprehensively explore the microbiota and metabolic changes in AD rats under SCP2 intervention, with the aim of elucidating the potential mechanisms of SCP2 in the treatment of AD. SCP2 showed significant therapeutic effects in AD rats, as evidenced by improved learning and memory capacity, reduced neuroinflammation, and restoration of the integrity of the intestinal barrier. Fecal metabolomic and microbiomic analyses revealed that SCP2 significantly modulated 19 endogenous metabolites and reversed gut microbiota disorders in AD rats. Moreover, SCP2 significantly increased the content of short-chain fatty acid (SCFAs) in the AD rats. Correlation analysis showed a significant correlation between gut microbes, metabolites and the content of SCFAs. Collectively, these findings will provide the basis for further development of SCP2.
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Affiliation(s)
- Jun Fu
- School of Pharmaceutical Sciences, Jilin University, Changchun 130021, China.; Jilin Provincial Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry, Changchun, Institute of Applied Chemistry, Chinese Academy of Sciences & National Center of Mass Spectrometry in Changchun, Changchun, 130022, China
| | - Jixun Li
- School of Pharmaceutical Sciences, Jilin University, Changchun 130021, China.; Jilin Provincial Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry, Changchun, Institute of Applied Chemistry, Chinese Academy of Sciences & National Center of Mass Spectrometry in Changchun, Changchun, 130022, China
| | - Yuzhen Sun
- School of Pharmaceutical Sciences, Jilin University, Changchun 130021, China.; Jilin Provincial Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry, Changchun, Institute of Applied Chemistry, Chinese Academy of Sciences & National Center of Mass Spectrometry in Changchun, Changchun, 130022, China
| | - Shu Liu
- Jilin Provincial Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry, Changchun, Institute of Applied Chemistry, Chinese Academy of Sciences & National Center of Mass Spectrometry in Changchun, Changchun, 130022, China
| | - Fengrui Song
- Jilin Provincial Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry, Changchun, Institute of Applied Chemistry, Chinese Academy of Sciences & National Center of Mass Spectrometry in Changchun, Changchun, 130022, China
| | - Zhongying Liu
- School of Pharmaceutical Sciences, Jilin University, Changchun 130021, China..
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L K, Ng TKS, Wee HN, Ching J. Gut-brain axis through the lens of gut microbiota and their relationships with Alzheimer's disease pathology: Review and recommendations. Mech Ageing Dev 2023; 211:111787. [PMID: 36736919 DOI: 10.1016/j.mad.2023.111787] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 01/05/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder that affects millions of people worldwide. Growing evidence suggests that the gut microbiome (GM) plays a pivotal role in the pathogenesis of AD through the microbiota-gut-brain axis (MGB). Alterations in GM composition and diversity have been observed in both animal models and in human patients with AD. GM dysbiosis has been implicated in increased intestinal permeability, blood-brain barrier (BBB) impairment, neuroinflammation and the development of hallmarks of AD. Further elucidation of the role of GM in AD could pave way for the development of holistic predictive methods for determining AD risk and progression of disease. Furthermore, accumulating evidence suggests that GM modulation could alleviate adverse symptoms of AD or serve as a preventive measure. In addition, increasing evidence shows that Type 2 Diabetes Mellitus (T2DM) is often comorbid with AD, with common GM alterations and inflammatory response, which could chart the development of GM-related treatment interventions for both diseases. We conclude by exploring the therapeutic potential of GM in alleviating symptoms of AD and in reducing risk. Furthermore, we also propose future directions in AD research, namely fecal microbiota transplantation (FMT) and precision medicine.
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Affiliation(s)
- Krishaa L
- Department of Biomedical Engineering, College of Design and Engineering, National University of Singapore, Singapore
| | - Ted Kheng Siang Ng
- Arizona State University, Edson College of Nursing and Health Innovation, USA.
| | - Hai Ning Wee
- Cardiovascular and Metabolic Disorders Programme, Duke-NUS Medical School, Singapore
| | - Jianhong Ching
- Cardiovascular and Metabolic Disorders Programme, Duke-NUS Medical School, Singapore; KK Research Centre, KK Women's and Children's Hospital, Singapore.
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25
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Ubeda C, Vázquez-Carretero MD, Luque-Tirado A, Ríos-Reina R, Rubio-Sánchez R, Franco-Macías E, García-Miranda P, Calonge ML, Peral MJ. Fecal Volatile Organic Compounds and Microbiota Associated with the Progression of Cognitive Impairment in Alzheimer's Disease. Int J Mol Sci 2022; 24:707. [PMID: 36614151 PMCID: PMC9821163 DOI: 10.3390/ijms24010707] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/22/2022] [Accepted: 12/27/2022] [Indexed: 01/04/2023] Open
Abstract
Metabolites produced by an altered gut microbiota might mediate the effects in the brain. Among metabolites, the fecal volatile organic compounds (VOCs) are considered to be potential biomarkers. In this study, we examined both the VOCs and bacterial taxa in the feces from healthy subjects and Alzheimer's disease (AD) patients at early and middle stages. Remarkably, 29 fecal VOCs and 13 bacterial genera were differentiated from the healthy subjects and the AD patients. In general, higher amounts of acids and esters were found in in the feces of the AD patients and terpenes, sulfur compounds and aldehydes in the healthy subjects. At the early stage of AD, the most relevant VOCs with a higher abundance were short-chain fatty acids and their producing bacteria, Faecalibacterium and Lachnoclostridium. Coinciding with the development of dementia in the AD patients, parallel rises of heptanoic acid and Peptococcus were observed. At a more advanced stage of AD, the microbiota and volatiles shifted towards a profile in the feces with increases in hexanoic acid, Ruminococcus and Blautia. The most remarkable VOCs that were associated with the healthy subjects were 4-ethyl-phenol and dodecanol, together with their possible producers Clostridium and Coprococcus. Our results revealed a VOCs and microbiota crosstalk in AD development and their profiles in the feces were specific depending on the stage of AD. Additionally, some of the most significant fecal VOCs identified in our study could be used as potential biomarkers for the initiation and progression of AD.
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Affiliation(s)
- Cristina Ubeda
- Departamento de Nutrición y Bromatología, Facultad de Farmacia, Universidad de Sevilla, 41012 Sevilla, Spain
| | | | - Andrea Luque-Tirado
- Unidad de Memoria, Servicio de Neurología, Hospital Universitario Virgen del Rocío, 41013 Sevilla, Spain
| | - Rocío Ríos-Reina
- Departamento de Nutrición y Bromatología, Facultad de Farmacia, Universidad de Sevilla, 41012 Sevilla, Spain
| | - Ricardo Rubio-Sánchez
- Laboratorio de Análisis Clínicos, Hospital Universitario Valme, 41014 Sevilla, Spain
| | - Emilio Franco-Macías
- Unidad de Memoria, Servicio de Neurología, Hospital Universitario Virgen del Rocío, 41013 Sevilla, Spain
| | - Pablo García-Miranda
- Departamento de Fisiología, Facultad de Farmacia, Universidad de Sevilla, 41012 Sevilla, Spain
| | - María L. Calonge
- Departamento de Fisiología, Facultad de Farmacia, Universidad de Sevilla, 41012 Sevilla, Spain
| | - María J. Peral
- Departamento de Fisiología, Facultad de Farmacia, Universidad de Sevilla, 41012 Sevilla, Spain
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26
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Bacterial DNAemia in Alzheimer's Disease and Mild Cognitive Impairment: Association with Cognitive Decline, Plasma BDNF Levels, and Inflammatory Response. Int J Mol Sci 2022; 24:ijms24010078. [PMID: 36613538 PMCID: PMC9820596 DOI: 10.3390/ijms24010078] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/13/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Microbial dysbiosis (MD) provokes gut barrier alterations and bacterial translocation in the bloodstream. The increased blood bacterial DNA (BB-DNA) may promote peripheral- and neuro-inflammation, contributing to cognitive impairment. MD also influences brain-derived neurotrophic factor (BDNF) production, whose alterations contribute to the etiopathogenesis of Alzheimer's disease (AD). The purpose of this study is to measure BB-DNA in healthy elderly controls (EC), and in patients with mild cognitive impairment (MCI) and AD to explore the effect on plasma BDNF levels (pBDNF), the inflammatory response, and the association with cognitive decline during a two-year follow-up. Baseline BB-DNA and pBDNF were significantly higher in MCI and AD than in EC. BB-DNA was positively correlated with pBDNF in AD, plasma Tumor necrosis factor-alpha (TNF-α), and Interleukin-10 (IL-10) levels in MCI. AD patients with BB-DNA values above the 50th percentile had lower baseline Mini-Mental State Examination (MMSE). After a two-year follow-up, AD patients with the highest BB-DNA tertile had a worse cognitive decline, while higher BB-DNA levels were associated with higher TNF-α and lower IL-10 in MCI. Our study demonstrates that, in early AD, the higher the BB-DNA levels, the higher the pBDNF levels, suggesting a defensive attempt; BB-DNA seems to play a role in the AD severity/progression; in MCI, higher BB-DNA may trigger an increased inflammatory response.
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27
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Zhao Y, Jaber VR, Pogue AI, Sharfman NM, Taylor C, Lukiw WJ. Lipopolysaccharides (LPSs) as Potent Neurotoxic Glycolipids in Alzheimer's Disease (AD). Int J Mol Sci 2022; 23:ijms232012671. [PMID: 36293528 PMCID: PMC9604166 DOI: 10.3390/ijms232012671] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/12/2022] [Accepted: 10/19/2022] [Indexed: 01/11/2023] Open
Abstract
Lipopolysaccharides (LPSs) are microbiome-derived glycolipids that are among the most potent pro-inflammatory neurotoxins known. In Homo sapiens, the major sources of LPSs are gastrointestinal (GI)-tract-resident facultative anaerobic Gram-negative bacilli, including Bacteroides fragilis and Escherichia coli. LPSs have been abundantly detected in aged human brain by multiple independent research investigators, and an increased abundance of LPSs around and within Alzheimer's disease (AD)-affected neurons has been found. Microbiome-generated LPSs and other endotoxins cross GI-tract biophysiological barriers into the systemic circulation and across the blood-brain barrier into the brain, a pathological process that increases during aging and in vascular disorders, including 'leaky gut syndrome'. Further evidence indicates that LPSs up-regulate pro-inflammatory transcription factor complex NF-kB (p50/p65) and subsequently a set of NF-kB-sensitive microRNAs, including miRNA-30b, miRNA-34a, miRNA-146a and miRNA-155. These up-regulated miRNAs in turn down-regulate a family of neurodegeneration-associated messenger RNA (mRNA) targets, including the mRNA encoding the neuron-specific neurofilament light (NF-L) chain protein. While NF-L has been reported to be up-regulated in peripheral biofluids in AD and other progressive and lethal pro-inflammatory neurodegenerative disorders, NF-L is significantly down-regulated within neocortical neurons, and this may account for neuronal atrophy, loss of axonal caliber and alterations in neuronal cell shape, modified synaptic architecture and network deficits in neuronal signaling capacity. This paper reviews and reveals the most current findings on the neurotoxic aspects of LPSs and how these pro-inflammatory glycolipids contribute to the biological mechanism of progressive, age-related and ultimately lethal neurodegenerative disorders. This recently discovered gut-microbiota-derived LPS-NF-kB-miRNA-30b-NF-L pathological signaling network: (i) underscores a direct positive pathological link between the LPSs of GI-tract microbes and the inflammatory neuropathology, disordered cytoskeleton, and disrupted synaptic-signaling of the AD brain and stressed human brain cells in primary culture; and (ii) is the first example of a microbiome-derived neurotoxic glycolipid having significant detrimental miRNA-mediated actions on the expression of NF-L, an abundant filamentous protein known to be important in the maintenance of neuronal and synaptic homeostasis.
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Affiliation(s)
- Yuhai Zhao
- LSU Neuroscience Center, Louisiana State University Health Science Center, New Orleans, LA 70112, USA
- Department of Cell Biology and Anatomy, LSU Health Science Center, New Orleans, LA 70112, USA
| | - Vivian R. Jaber
- LSU Neuroscience Center, Louisiana State University Health Science Center, New Orleans, LA 70112, USA
| | | | - Nathan M. Sharfman
- LSU Neuroscience Center, Louisiana State University Health Science Center, New Orleans, LA 70112, USA
| | - Christopher Taylor
- Department of Microbiology, Immunology & Parasitology, LSU Health Science Center, New Orleans, LA 70112, USA
| | - Walter J. Lukiw
- LSU Neuroscience Center, Louisiana State University Health Science Center, New Orleans, LA 70112, USA
- Alchem Biotech Research, Toronto, ON M5S 1A8, Canada
- Department of Ophthalmology, LSU Health Science Center, New Orleans, LA 70112, USA
- Department Neurology, Louisiana State University Health Science Center, New Orleans, LA 70112, USA
- Correspondence:
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