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Zhu F, Li C, Chu F, Tian X, Zhu J. Target Dysbiosis of Gut Microbes as a Future Therapeutic Manipulation in Alzheimer's Disease. Front Aging Neurosci 2020; 12:544235. [PMID: 33132894 PMCID: PMC7572848 DOI: 10.3389/fnagi.2020.544235] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 08/24/2020] [Indexed: 12/14/2022] Open
Abstract
Alzheimer’s disease (AD) is commonly an age-associated dementia with neurodegeneration. The pathogenesis of AD is complex and still remains unclear. The inflammation, amyloid β (Aβ), and neurofibrillary tangles as well misfolded tau protein in the brain may contribute to the occurrence and development of AD. Compared with tau protein, Aβ is less toxic. So far, all efforts made in the treatments of AD with targeting these pathogenic factors were unsuccessful over the past decades. Recently, many studies demonstrated that changes of the intestinal environment and gut microbiota via gut–brain axis pathway can cause neurological disorders, such as AD, which may be involved in the pathogenesis of AD. Thus, remodeling the gut microbiota by various ways to maintain their balance might be a novel therapeutic strategy for AD. In the review article, we analyzed the characteristics of gut microbiota and its dysbiosis in AD and its animal models and investigated the possibility of targeting the gut microbiota in the treatment of the patients with AD in the future.
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Affiliation(s)
- Feiqi Zhu
- Cognitive Impairment Ward of Neurology Department, The Third Affiliated Hospital of Shenzhen University Medical College, Shenzhen, China
| | - Chunrong Li
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Fengna Chu
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China.,Division of Neurogeriatrcs, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
| | - Xiaoping Tian
- Cognitive Impairment Ward of Neurology Department, The Third Affiliated Hospital of Shenzhen University Medical College, Shenzhen, China
| | - Jie Zhu
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China.,Division of Neurogeriatrcs, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
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Jaeger V, DeMorrow S, McMillin M. The Direct Contribution of Astrocytes and Microglia to the Pathogenesis of Hepatic Encephalopathy. J Clin Transl Hepatol 2019; 7:352-361. [PMID: 31915605 PMCID: PMC6943208 DOI: 10.14218/jcth.2019.00025] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/07/2019] [Accepted: 10/24/2019] [Indexed: 02/06/2023] Open
Abstract
Hepatic encephalopathy is a neurological complication resulting from loss of hepatic function and is associated with poor clinical outcomes. During acute liver failure over 20% of mortality can be associated with the development of hepatic encephalopathy. In patients with liver cirrhosis, 1-year survival for those that develop overt hepatic encephalopathy is under 50%. The pathogenesis of hepatic encephalopathy is complicated due to the multiple disruptions in homeostasis that occur following a reduction in liver function. Of these, elevations of ammonia and neuroinflammation have been shown to play a significant contributing role to the development of hepatic encephalopathy. Disruption of the urea cycle following liver dysfunction leads to elevations of circulating ammonia, which enter the brain and disrupt the functioning of astrocytes. This results in dysregulation of metabolic pathways in astrocytes, oxidative stress and cerebral edema. Besides ammonia, circulating chemokines and cytokines are increased following liver injury, leading to activation of microglia and a subsequent neuroinflammatory response. The combination of astrocyte dysfunction and microglia activation are significant contributing factors to the pathogenesis of hepatic encephalopathy.
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Affiliation(s)
- Victoria Jaeger
- Baylor Scott & White Health, Department of Internal Medicine, Temple, TX, USA
| | - Sharon DeMorrow
- Texas A&M University Health Science Center, Department of Medical Physiology, Temple, TX, USA
- Central Texas Veterans Health Care System, Temple, TX, USA
- University of Texas at Austin, Dell Medical School, Department of Internal Medicine, Austin, TX, USA
- University of Texas at Austin, College of Pharmacy, Austin, TX, USA
| | - Matthew McMillin
- Texas A&M University Health Science Center, Department of Medical Physiology, Temple, TX, USA
- Central Texas Veterans Health Care System, Temple, TX, USA
- University of Texas at Austin, Dell Medical School, Department of Internal Medicine, Austin, TX, USA
- Correspondence to: Matthew McMillin, University of Texas at Austin Dell Medical School, 1601 Trinity Street, Building B, Austin, TX 78701, USA. Tel: +1-512-495-5037, Fax: +1-512-495-5839, E-mail:
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Merino JJ, Cabaña-Muñoz ME, Toledano Gasca A, Garcimartín A, Benedí J, Camacho-Alonso F, Parmigiani-Izquierdo JM. Elevated Systemic L-Kynurenine/L-Tryptophan Ratio and Increased IL-1 Beta and Chemokine (CX3CL1, MCP-1) Proinflammatory Mediators in Patients with Long-Term Titanium Dental Implants. J Clin Med 2019; 8:jcm8091368. [PMID: 31480733 PMCID: PMC6780981 DOI: 10.3390/jcm8091368] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 01/04/2023] Open
Abstract
Titanium is the mean biocompatible metal found in dental titanium alloys (Ti-6Al-4V). The safety of certain dental biomaterial amalgams has been questioned in patients. The levels of several systemic cytokines (interleukin (IL)-1 beta, IL-4: pg/mL) and chemokines (monocyte chemoattractant protein-1 (MCP-1), soluble fractalkine (CX3CL1: pg/mL) were determined using ELISA and compared between these study groups. The study included 30 controls without dental materials (cont), 57 patients with long-term titanium dental implants plus amalgams (A + I group) as well as 55 patients with long-term dental amalgam alone (A group). All patients (except controls) have had dental titanium implants (Ti-6Al-4V) and/or amalgams for at least 10 years (average: 15 years). We evaluated whether systemic levels of cytokines/chemokines, kyn/L-trp ratio and aromatic amino acid levels (HPLC: mM/L, Phe, L-Trp, His, Treo) could be altered in patients with long-term dental titanium and/or amalgams. These systemic markers were evaluated in 142 patients. The A + I group had higher L-Kynurenine/L-Tryptophan ratios than patients with long-term dental amalgam fillings alone (A). In addition, levels of IL-1 Beta cytokine, CX3CL1 and MCP-1 chemokines were higher in the A + I group than in the A group (A). The increased L-kyn/L-trp ratio and MCP-1 and fractalkine receptor (CX3CR1) elevations could suggest enhanced chemotactic responses by these chemokines in the A + I group.
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Affiliation(s)
- José Joaquín Merino
- Departamento de Farmacología, Farmacognosia y Botánica, Facultad de Farmacia, Universidad Complutense de Madrid (U.C.M), c/Plaza Ramón y Cajal s/n, 28040 Madrid, Spain.
- Centro CIROM, Centro de Implantología y Rehabilitación Oral Multidisciplinaria, 30001 Murcia, Spain.
| | | | | | - Alba Garcimartín
- Departamento de Farmacología, Farmacognosia y Botánica, Facultad de Farmacia, Universidad Complutense de Madrid (U.C.M), c/Plaza Ramón y Cajal s/n, 28040 Madrid, Spain
| | - Juana Benedí
- Departamento de Farmacología, Farmacognosia y Botánica, Facultad de Farmacia, Universidad Complutense de Madrid (U.C.M), c/Plaza Ramón y Cajal s/n, 28040 Madrid, Spain
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Aller MA, Arias N, Blanco-Rivero J, Arias JL, Arias J. Hepatic encephalopathy: Sometimes more portal than hepatic. J Gastroenterol Hepatol 2019; 34:490-494. [PMID: 30345537 DOI: 10.1111/jgh.14514] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 10/08/2018] [Indexed: 12/29/2022]
Abstract
Hepatic encephalopathy is a severe complication of both chronic and acute liver diseases. The term hepatic encephalopathy stems from the belief that hepatic insufficiency is its fundamental etiopathogenic factor. However, most clinical cases show liver failure along with mesenteric venous portal hypertension. This portal hypertension would explain the abnormal mechanical forces suffered by the digestive tract in the early stages of the disorder. These forces could regulate some gut biochemical pathological pathways in a process known as mechanotransduction. Thus, portal hypertension would begin with the establishment of a mechanotransduced afferent or sensory inflammatory gut-brain pathway, resulting in functional and structural changes in the central nervous system. In this review, we will revisit the term "hepatic encephalopathy" in light of new results where portal hypertension occurs before liver failure and is accompanied by brain changes. Moreover, we will point out cellular links that can explain the microbiota, immune, gut, and brain axis disturbances found in this disorder.
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Affiliation(s)
- Maria-Angeles Aller
- Department of Surgery, School of Medicine, Complutense University of Madrid, Madrid, Spain
| | - Natalia Arias
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,INEUROPA (Instituto de Neurociencias del Principado de Asturias), Oviedo, Spain
| | - Javier Blanco-Rivero
- Department of Physiology, School of Medicine, Instituto de Investigación Sanitaria del Hospital Universitario La Paz (Idi PAZ), Autonoma University of Madrid, Madrid, Spain
| | - Jorge L Arias
- INEUROPA (Instituto de Neurociencias del Principado de Asturias), Oviedo, Spain.,Laboratory of Neuroscience, Department of Psychology, University of Oviedo, Asturias, Spain
| | - Jaime Arias
- Department of Surgery, School of Medicine, Complutense University of Madrid, Madrid, Spain
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Aller MA, Arias N, Peral I, García-Higarza S, Arias JL, Arias J. Embrionary way to create a fatty liver in portal hypertension. World J Gastrointest Pathophysiol 2017; 8:39-50. [PMID: 28573066 PMCID: PMC5437501 DOI: 10.4291/wjgp.v8.i2.39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/18/2017] [Accepted: 03/02/2017] [Indexed: 02/06/2023] Open
Abstract
Portal hypertension in the rat by triple partial portal vein ligation produces an array of splanchnic and systemic disorders, including hepatic steatosis. In the current review these alterations are considered components of a systemic inflammatory response that would develop through three overlapping phenotypes: The neurogenic, the immune and the endocrine. These three inflammatory phenotypes could resemble the functions expressed during embryonic development of mammals. In turn, the inflammatory phenotypes would be represented in the embryo by two functional axes, that is, a coelomic-amniotic axis and a trophoblastic yolk-sac or vitelline axis. In this sense, the inflammatory response developed after triple partial portal vein ligation in the rat would integrate both functional embryonic axes on the liver interstitial space of Disse. If so, this fact would favor the successive development of steatosis, steatohepatitis and fibrosis. Firstly, these recapitulated embryonic functions would produce the evolution of liver steatosis. In this way, this fat liver could represent a yolk-sac-like in portal hypertensive rats. After that, the systemic recapitulation of these embryonic functions in experimental prehepatic portal hypertension would consequently induce a gastrulation-like response in which a hepatic wound healing reaction or fibrosis occur. In conclusion, studying the mechanisms involved in embryonic development could provide key results for a better understanding of the nonalcoholic fatty liver disease etiopathogeny.
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McMillin M, Grant S, Frampton G, Andry S, Brown A, DeMorrow S. Fractalkine suppression during hepatic encephalopathy promotes neuroinflammation in mice. J Neuroinflammation 2016; 13:198. [PMID: 27561705 PMCID: PMC5000400 DOI: 10.1186/s12974-016-0674-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 08/17/2016] [Indexed: 12/31/2022] Open
Abstract
Background Acute liver failure is associated with numerous systemic consequences including neurological dysfunction, termed hepatic encephalopathy, which contributes to mortality and is a challenge to manage in the clinic. During hepatic encephalopathy, microglia activation and neuroinflammation occur due to dysregulated cell signaling and an increase of toxic metabolites in the brain. Fractalkine is a chemokine that is expressed primarily in neurons and through signaling with its receptor CX3CR1 on microglia, leads to microglia remaining in a quiescent state. Fractalkine is often suppressed during neuropathies that are characterized by neuroinflammation. However, the expression and subsequent role of fractalkine on microglia activation and the pathogenesis of hepatic encephalopathy due to acute liver failure is unknown. Methods Hepatic encephalopathy was induced in mice via injection of azoxymethane (AOM) or saline for controls. Subsets of these mice were implanted with osmotic minipumps that infused soluble fractalkine or saline into the lateral ventricle of the brain. Neurological decline and the latency to coma were recorded in these mice, and brain, serum, and liver samples were collected. Neurons or microglia were isolated from whole brain samples using immunoprecipitation. Liver damage was assessed using hematoxylin and eosin staining and by measuring serum liver enzyme concentrations. Fractalkine and CX3CR1 expression were assessed by real-time PCR, and proinflammatory cytokine expression was assessed using ELISA assays. Results Following AOM administration, fractalkine expression is suppressed in the cortex and in isolated neurons compared to vehicle-treated mice. CX3CR1 is suppressed in isolated microglia from AOM-treated mice. Soluble fractalkine infusion into the brain significantly reduced neurological decline in AOM-treated mice compared to saline-infused AOM-treated mice. Infusion of soluble fractalkine into AOM-treated mice reduced liver damage, lessened microglia activation, and suppressed expression of chemokine ligand 2, interleukin-6, and tumor necrosis factor alpha compared to saline-infused mice. Conclusions These findings suggest that fractalkine-mediated signaling is suppressed in the brain following the development of hepatic encephalopathy. Supplementation of AOM-treated mice with soluble fractalkine led to improved outcomes, which identifies this pathway as a possible therapeutic target for the management of hepatic encephalopathy following acute liver injury.
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Affiliation(s)
- Matthew McMillin
- Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, TX, USA.,Central Texas Veterans Healthcare System, 1901 S. 1st Street, Building 205, Temple, TX, 76504, USA
| | - Stephanie Grant
- Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, TX, USA.,Central Texas Veterans Healthcare System, 1901 S. 1st Street, Building 205, Temple, TX, 76504, USA
| | - Gabriel Frampton
- Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, TX, USA.,Central Texas Veterans Healthcare System, 1901 S. 1st Street, Building 205, Temple, TX, 76504, USA
| | - Sarah Andry
- Department of Internal Medicine, Baylor Scott & White Health, 2401 S. 31st Street, Temple, TX, 76508, USA
| | - Adam Brown
- Department of Internal Medicine, Baylor Scott & White Health, 2401 S. 31st Street, Temple, TX, 76508, USA
| | - Sharon DeMorrow
- Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, TX, USA. .,Central Texas Veterans Healthcare System, 1901 S. 1st Street, Building 205, Temple, TX, 76504, USA.
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Main target of minimal hepatic encephalopathy: Morphophysiological, inflammatory and metabolic view. Physiol Behav 2015; 149:247-54. [PMID: 26079568 DOI: 10.1016/j.physbeh.2015.06.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 03/25/2015] [Accepted: 06/10/2015] [Indexed: 12/12/2022]
Abstract
Although often not considered clinically relevant and, therefore, not diagnosed or treated, minimal hepatic encephalopathy (MHE) has been shown to affect daily functioning, quality of life, driving and overall mortality. To discover early impairments involved in MHE, we studied one of its precipitating factors, portal hypertension. Rats were trained on a stimulus-response task using the Morris water maze. Two groups of animals were used: a SHAM (sham-operated) group (n= 13) and a portal hypertension (PH) group (n= 13). The triple portal vein ligation method was used to create an animal model of an early developmental phase of HE. Brain metabolic activity was studied with cytochrome c-oxidase histochemistry (C.O.). Neuronal nuclear volume was assessed by nucleator probe; the number of glial fibrillary acidic protein-immunoreactive astrocytes (GFAP-IR) and proinflammatory mediators was measured. The results revealed that the PH group was not able to reach the behavioural criterion, in contrast to the SHAM group. The metabolic brain consumption revealed decreased C.O. activity in the ventral striatum. The PH group showed lower density of GFAP-IR and an increase in the tumour necrotic factor-α (TNF-α). The PH group showed decreased neuronal nuclear volume in the dorsal striatum. On the contrary, increased neuronal nuclear volume was found in the ventral striatum. For the first time, a relationship has been established between inflammation, astrocytic and neural damage, and brain metabolic impairment in a model of MHE. Disruption of the striatum and related structures was highlighted as the main target in early stages of HE. Finally, a simple task was presented to assess the subtle impairments found in the clinic, which could provide fresh insights into the development of new tools for the assessment of MHE.
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Manti S, Marseglia L, D'Angelo G, Filippelli M, Cuppari C, Gitto E, Romano C, Arrigo T, Salpietro C. Portal hypertension as immune mediate disease. HEPATITIS MONTHLY 2014; 14:e18625. [PMID: 24976841 PMCID: PMC4071352 DOI: 10.5812/hepatmon.18625] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 04/13/2014] [Indexed: 12/11/2022]
Abstract
CONTEXT Portal Hypertension (PH) is a progressive complication due to chronic liver disease. In addition to pathophysiologic changes in the micro-circulation, in PH are established fibrous tissue (periportal fibrous septal) and regenerative hyperplastic nodules (from micro- to macro-nodules) promoting hepatic architectural distortion. EVIDENCE ACQUISITION A literature search of electronic databases was undertaken for the major studies published from 1981 to today. The databases searched were: PubMed, EMBASE, Orphanet, Midline and Cochrane Library. We used the keywords: "portal hypertension, children, immune system, endocrine system, liver fibrosis". RESULTS It is believed that PH results from three "phenotype": ischemia-reperfusion, involving nervous system (NS); edema and oxidative damage, involving immune system; inflammation and angiogenesis, involving endocrine system. However, its exact cause still underdiagnosed and unknown. CONCLUSIONS PH is a dynamic and potentially reversible process. Researchers have tried to demonstrate mechanisms underlying PH and its related-complications. This review focuses on the current knowledge regarding the pathogenesis, and immune, endocrine-metabolic factors of disease. The strong positive association between immune system and development of PH could be efficient to identify non-invasive markers of disease, to modify prognosis of PH, and to development and application of specific and individual anti-inflammatory therapy.
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Affiliation(s)
- Sara Manti
- Department of Pediatric Sciences, Genetics and Pediatric Immunology Unit, University of Messina, Messina, Italy
| | - Lucia Marseglia
- Department of Pediatric Sciences, Genetics and Pediatric Immunology Unit, University of Messina, Messina, Italy
| | - Gabriella D'Angelo
- Department of Pediatric Sciences, Genetics and Pediatric Immunology Unit, University of Messina, Messina, Italy
| | - Martina Filippelli
- Department of Pediatric Sciences, Genetics and Pediatric Immunology Unit, University of Messina, Messina, Italy
| | - Caterina Cuppari
- Department of Pediatric Sciences, Genetics and Pediatric Immunology Unit, University of Messina, Messina, Italy
| | - Eloisa Gitto
- Department of Pediatric Sciences, Genetics and Pediatric Immunology Unit, University of Messina, Messina, Italy
| | - Claudio Romano
- Department of Pediatric Sciences, Genetics and Pediatric Immunology Unit, University of Messina, Messina, Italy
| | - Teresa Arrigo
- Department of Pediatric Sciences, Genetics and Pediatric Immunology Unit, University of Messina, Messina, Italy
- Corresponding Author: Teresa Arrigo, Department of Pediatric Sciences, Genetics and Pediatric Immunology Unit, University of Messina, Messina, Italy. Tel +39-902213130, Fax: +39-902213788, E-mail:
| | - Carmelo Salpietro
- Department of Pediatric Sciences, Genetics and Pediatric Immunology Unit, University of Messina, Messina, Italy
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