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Wu M, Cheng Y, Zhang R, Han W, Jiang H, Bi C, Zhang Z, Ye M, Lin X, Liu Z. Molecular mechanism and therapeutic strategy of bile acids in Alzheimer's disease from the emerging perspective of the microbiota-gut-brain axis. Biomed Pharmacother 2024; 178:117228. [PMID: 39088965 DOI: 10.1016/j.biopha.2024.117228] [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: 04/21/2024] [Revised: 07/19/2024] [Accepted: 07/28/2024] [Indexed: 08/03/2024] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid-β outside neurons and Tau protein inside neurons. Various pathological mechanisms are implicated in AD, including brain insulin resistance, neuroinflammation, and endocrinal dysregulation of adrenal corticosteroids. These factors collectively contribute to neuronal damage and destruction. Recently, bile acids (BAs), which are metabolites of cholesterol, have shown neuroprotective potential against AD by targeting the above pathological changes. BAs can enter the systematic circulation and cross the blood-brain barrier, subsequently exerting neuroprotective effects by targeting several endogenous receptors. Additionally, BAs interact with the microbiota-gut-brain (MGB) axis to improve immune and neuroendocrine function during AD episodes. Gut microbes impact BA signaling in the brain through their involvement in BA biotransformation. In this review, we summarize the role and molecular mechanisms of BAs in AD while considering the MGB axis and propose novel strategies for preventing the onset and progression of AD.
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Affiliation(s)
- Menglu Wu
- Clinical Laboratory, Shaoxing Seventh People's Hospital (Affiliated Mental Health Center, Medical College of Shaoxing University), Shaoxing, Zhejiang, China; Department of Behavioral Neurosciences, Science Research Center of Medical School, Shaoxing University, Shaoxing, Zhejiang, China
| | - Yongyi Cheng
- Department of Behavioral Neurosciences, Science Research Center of Medical School, Shaoxing University, Shaoxing, Zhejiang, China
| | - Ruolin Zhang
- Department of Behavioral Neurosciences, Science Research Center of Medical School, Shaoxing University, Shaoxing, Zhejiang, China
| | - Wenwen Han
- Department of Behavioral Neurosciences, Science Research Center of Medical School, Shaoxing University, Shaoxing, Zhejiang, China
| | - Hanqi Jiang
- Department of Behavioral Neurosciences, Science Research Center of Medical School, Shaoxing University, Shaoxing, Zhejiang, China
| | - Chenchen Bi
- Department of Behavioral Neurosciences, Science Research Center of Medical School, Shaoxing University, Shaoxing, Zhejiang, China
| | - Ziyi Zhang
- Department of Behavioral Neurosciences, Science Research Center of Medical School, Shaoxing University, Shaoxing, Zhejiang, China
| | - Mengfei Ye
- Department of Psychiatry, Shaoxing Seventh People's Hospital (Affiliated Mental Health Center, Medical College of Shaoxing University), Shaoxing, Zhejiang, China
| | - Xiuqin Lin
- Clinical Laboratory, Shaoxing Seventh People's Hospital (Affiliated Mental Health Center, Medical College of Shaoxing University), Shaoxing, Zhejiang, China.
| | - Zheng Liu
- Department of Behavioral Neurosciences, Science Research Center of Medical School, Shaoxing University, Shaoxing, Zhejiang, China; Department of Pharmacology, School of Medicine, Shaoxing University, Shaoxing, Zhejiang, China.
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Shibuya T, Sato A, Nishimoto-Kusunose S, Yoshizawa K, Higashi T. Further evidence for blood-to-brain influx of unconjugated bile acids by passive diffusion: Determination of their brain-to-serum concentration ratios in rats by LC/MS/MS. Steroids 2024; 204:109397. [PMID: 38508483 DOI: 10.1016/j.steroids.2024.109397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 02/28/2024] [Accepted: 03/17/2024] [Indexed: 03/22/2024]
Abstract
Bile acids (BAs) reside in the brain and are probably involved in some neurological disorders. The view that most of unconjugated BAs in the brain are derived across the blood-brain barrier from the periphery by passive diffusion depending on their hydrophobicity is currently dominant, but some studies have made conflicting claims. In this study, the correlation analysis between the rat brain and serum levels of unconjugated BAs with a wider range of hydrophobicity was conducted to obtain further evidence about the blood-to-brain influx of unconjugated BAs by passive diffusion. We first developed the precise, accurate and matrix effect-free LC/ESI-MS/MS methods for quantifying eight major unconjugated BAs in the rat brain and serum. Derivatization was employed for increasing the assay sensitivity and specificity. The analysis using these methods reproduced the strong positive correlations between the brain and serum levels, and significant higher concentrations in the serum than in the brain for all the unconjugated BAs. The BA with the higher logPow (hydrophobicity) had the higher brain-to-serum concentration ratio (mono- > di- > trihydroxy BAs). Furthermore, the hydrophobicity was considered as the stronger factor for the blood-to-brain influx of the BAs than the serum protein binding ratio. Thus, this study provided further evidence supporting that passive diffusion is the major mechanism for the blood-to-brain influx of the unconjugated BAs.
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Affiliation(s)
- Toma Shibuya
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Anri Sato
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Shoich Nishimoto-Kusunose
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Kazumi Yoshizawa
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Tatsuya Higashi
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
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Duarte-Silva S, Da Silva JD, Monteiro-Fernandes D, Costa MD, Neves-Carvalho A, Raposo M, Soares-Cunha C, Correia JS, Nogueira-Goncalves G, Fernandes HS, Oliveira S, Ferreira-Fernandes AR, Rodrigues F, Pereira-Sousa J, Vilasboas-Campos D, Guerreiro S, Campos J, Meireles-Costa L, Rodrigues CM, Cabantous S, Sousa SF, Lima M, Teixeira-Castro A, Maciel P. Glucocorticoid receptor-dependent therapeutic efficacy of tauroursodeoxycholic acid in preclinical models of spinocerebellar ataxia type 3. J Clin Invest 2024; 134:e162246. [PMID: 38227368 PMCID: PMC10904051 DOI: 10.1172/jci162246] [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: 05/31/2022] [Accepted: 01/09/2024] [Indexed: 01/17/2024] Open
Abstract
Spinocerebellar ataxia type 3 (SCA3) is an adult-onset neurodegenerative disease caused by a polyglutamine expansion in the ataxin-3 (ATXN3) gene. No effective treatment is available for this disorder, other than symptom-directed approaches. Bile acids have shown therapeutic efficacy in neurodegenerative disease models. Here, we pinpointed tauroursodeoxycholic acid (TUDCA) as an efficient therapeutic, improving the motor and neuropathological phenotype of SCA3 nematode and mouse models. Surprisingly, transcriptomic and functional in vivo data showed that TUDCA acts in neuronal tissue through the glucocorticoid receptor (GR), but independently of its canonical receptor, the farnesoid X receptor (FXR). TUDCA was predicted to bind to the GR, in a similar fashion to corticosteroid molecules. GR levels were decreased in disease-affected brain regions, likely due to increased protein degradation as a consequence of ATXN3 dysfunction being restored by TUDCA treatment. Analysis of a SCA3 clinical cohort showed intriguing correlations between the peripheral expression of GR and the predicted age at disease onset in presymptomatic subjects and FKBP5 expression with disease progression, suggesting this pathway as a potential source of biomarkers for future study. We have established a novel in vivo mechanism for the neuroprotective effects of TUDCA in SCA3 and propose this readily available drug for clinical trials in SCA3 patients.
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Affiliation(s)
- Sara Duarte-Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Jorge Diogo Da Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
- Medical Genetics Center Dr. Jacinto de Magalhães, Santo António University Hospital Center, Porto, Portugal
- Unit for Multidisciplinary Research in Biomedicine, Abel Salazar Biomedical Sciences Institute, Porto University, Porto, Portugal
| | - Daniela Monteiro-Fernandes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Marta Daniela Costa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Andreia Neves-Carvalho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Mafalda Raposo
- Instituto de Biologia Molecular e Celular (IBMC), Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
- Faculdade de Ciências e Tecnologia, Universidade dos Açores, Ponta Delgada, Portugal
| | - Carina Soares-Cunha
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Joana S. Correia
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Gonçalo Nogueira-Goncalves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Henrique S. Fernandes
- UCIBIO – Applied Molecular Biosciences Unit, BioSIM – Departamento de Biomedicina and
- Associate Laboratory i4HB – Institute for Health and Bioeconomy, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Stephanie Oliveira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Ana Rita Ferreira-Fernandes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Fernando Rodrigues
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Joana Pereira-Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Daniela Vilasboas-Campos
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Sara Guerreiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Jonas Campos
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Liliana Meireles-Costa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Cecilia M.P. Rodrigues
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Stephanie Cabantous
- Cancer Research Center of Toulouse (CRCT), Inserm, Université de Toulouse, UPS, CNRS, Toulouse, France
| | - Sergio F. Sousa
- UCIBIO – Applied Molecular Biosciences Unit, BioSIM – Departamento de Biomedicina and
- Associate Laboratory i4HB – Institute for Health and Bioeconomy, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Manuela Lima
- Faculdade de Ciências e Tecnologia, Universidade dos Açores, Ponta Delgada, Portugal
| | - Andreia Teixeira-Castro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Patricia Maciel
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s – PT Government Associate Laboratory, Braga/Guimarães, Portugal
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Fan C, Xu J, Tong H, Fang Y, Chen Y, Lin Y, Chen R, Chen F, Wu G. Gut-brain communication mediates the impact of dietary lipids on cognitive capacity. Food Funct 2024; 15:1803-1824. [PMID: 38314832 DOI: 10.1039/d3fo05288e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Cognitive impairment, as a prevalent symptom of nervous system disorders, poses one of the most challenging aspects in the management of brain diseases. Lipids present in the cell membranes of all neurons within the brain and dietary lipids can regulate the cognition and memory function. In recent years, the advancements in gut microbiome research have enabled the exploration of dietary lipids targeting the gut-brain axis as a strategy for regulating cognition. This present review provides an in-depth overview of how lipids modulate cognition via the gut-brain axis depending on metabolic, immune, neural and endocrine pathways. It also comprehensively analyzes the effects of diverse lipids on the gut microbiota and intestinal barrier function, thereby affecting the central nervous system and cognitive capacity. Moreover, comparative analysis of the positive and negative effects is presented between beneficial and detrimental lipids. The former encompass monounsaturated fatty acids, short-chain fatty acids, omega-3 polyunsaturated fatty acids, phospholipids, phytosterols, fungal sterols and bioactive lipid-soluble vitamins, as well as lipid-derived gut metabolites, whereas the latter (detrimental lipids) include medium- or long-chain fatty acids, excessive proportions of n-6 polyunsaturated fatty acids, industrial trans fatty acids, and zoosterols. To sum up, the focus of this review is on how gut-brain communication mediates the impact of dietary lipids on cognitive capacity, providing a novel theoretical foundation for promoting brain cognitive health and scientific lipid consumption patterns.
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Affiliation(s)
- Chenhan Fan
- School of Public Health, Health Science Center, Ningbo University, Ningbo, Zhejiang, 315211, China.
| | - Jingxuan Xu
- School of Public Health, Health Science Center, Ningbo University, Ningbo, Zhejiang, 315211, China.
| | - Haoxiang Tong
- School of Public Health, Health Science Center, Ningbo University, Ningbo, Zhejiang, 315211, China.
| | - Yucheng Fang
- School of Public Health, Health Science Center, Ningbo University, Ningbo, Zhejiang, 315211, China.
| | - Yiming Chen
- School of Public Health, Health Science Center, Ningbo University, Ningbo, Zhejiang, 315211, China.
| | - Yangzhuo Lin
- School of Basic Medical Science, Health Science Center, Ningbo University, Ningbo, Zhejiang, 315211, P. R. China
| | - Rui Chen
- School of Basic Medical Science, Health Science Center, Ningbo University, Ningbo, Zhejiang, 315211, P. R. China
| | - Fuhao Chen
- School of Basic Medical Science, Health Science Center, Ningbo University, Ningbo, Zhejiang, 315211, P. R. China
| | - Guoqing Wu
- School of Public Health, Health Science Center, Ningbo University, Ningbo, Zhejiang, 315211, China.
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Liu L, Zhou S, Zaufel A, Xie Z, Racedo S, Wagner M, Zollner G, Fickert P, Zhang Q. Bile acids regulate SF-1 to alter cholesterol balance in adrenocortical cells via S1PR2. Biochem Biophys Res Commun 2024; 692:149342. [PMID: 38061283 DOI: 10.1016/j.bbrc.2023.149342] [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: 11/21/2023] [Accepted: 11/24/2023] [Indexed: 01/06/2024]
Abstract
Glucocorticoid synthesis typically occurs in adrenal cortex and is influenced by cholesterol balance, since cholesterol is the sole precursor of steroids. Bile acids as the signaling molecules, have been shown to promote steroidogenesis in steroidogenic cells. However, whether bile acids directly regulate cholesterol balance remains elusive. In this study, we prepared cholestatic mouse models and cultured human adrenocortical cells (H295R) treated with taurochenodeoxycholic acid (TCDCA) to determine transcription levels of cholesterol metabolism associated genes and cholesterol concentrations in adrenocortical cells. Results showed that common bile duct ligation (CBDL) and chenodeoxycholic acid (CDCA) feeding elevated the mRNA levels of Abca1, Cyp51, Hmgcr, Srb1, and Mc2r in adrenals of mice. Meanwhile, the concentrations of total cholesterol and cholesteryl ester in adrenals of CBDL and CDCA-fed mice were dramatically lowered. The total and phosphorylation levels of HSL in adrenal glands of CBDL mice were also enhanced. Similarly, TCDCA treatment in H295R cells decreased intracellular concentrations of total cholesterol and cholesteryl ester and increased transcription levels of SRB1, MC2R, and HSL as well. Inhibition of bile acids' receptor sphingosine 1-phosphate receptor 2 (S1PR2), extracellular signal-regulated kinase (ERK) phosphorylation, and steroidogenic factor 1 (SF-1) respectively successfully abolished effect of TCDCA on H295R cells. SF-1s was found to be phosphorylated at Thr75 in TCDCA-treated H295R cells. While a mild increase of intracellular cAMP concentration was detected upon TCDCA treatment, inhibition of PKA activity with Rp-Isomer in H295R cells failed to decrease the expression of SF-1 and its target genes. Our findings suggest that conjugated bile acids affect cholesterol balance through regulation of SF-1 in adrenocortical cells so as to provide an adequate cholesterol supply for glucocorticoid synthesis, which improves and enriches our understanding of the mechanism whereby bile acids regulate cholesterol balance to affect adrenal function.
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Affiliation(s)
- Lei Liu
- Department of Endocrinology, the First Affiliated Hospital of Anhui Medical University, Hefei City, Anhui Province, People's Republic of China.
| | - Shufan Zhou
- Department of Endocrinology, the First Affiliated Hospital of Anhui Medical University, Hefei City, Anhui Province, People's Republic of China
| | - Alex Zaufel
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria.
| | - Zhenhui Xie
- Department of Endocrinology, the First Affiliated Hospital of Anhui Medical University, Hefei City, Anhui Province, People's Republic of China
| | - Silvia Racedo
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Martin Wagner
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria.
| | - Gernot Zollner
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria.
| | - Peter Fickert
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria.
| | - Qiu Zhang
- Department of Endocrinology, the First Affiliated Hospital of Anhui Medical University, Hefei City, Anhui Province, People's Republic of China.
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Pan I, Issac PK, Rahman MM, Guru A, Arockiaraj J. Gut-Brain Axis a Key Player to Control Gut Dysbiosis in Neurological Diseases. Mol Neurobiol 2023:10.1007/s12035-023-03691-3. [PMID: 37851313 DOI: 10.1007/s12035-023-03691-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 10/02/2023] [Indexed: 10/19/2023]
Abstract
Parkinson's disease is a chronic neuropathy characterised by the formation of Lewy bodies (misfolded alpha-synuclein) in dopaminergic neurons of the substantia nigra and other parts of the brain. Dopaminergic neurons play a vital role in generating both motor and non-motor symptoms. Finding therapeutic targets for Parkinson's disease (PD) is hindered due to an incomplete understanding of the disease's pathophysiology. Existing evidence suggests that the gut microbiota participates in the pathogenesis of PD via immunological, neuroendocrine, and direct neural mechanisms. Gut microbial dysbiosis triggers the loss of dopaminergic neurons via mitochondrial dysfunction. Gut dysbiosis triggers bacterial overgrowth in the small intestine, which increases the permeability barrier and induces systemic inflammation. It results in excessive stimulation of the innate immune system. In addition to that, activation of enteric neurons and enteric glial cells initiates the aggregation of alpha-synuclein. This alpha-synucleinopathy thus affects all levels of the brain-gut axis, including the central, autonomic, and enteric nervous systems. Though the neurobiological signaling cascade between the gut microbiome and the central nervous system is poorly understood, gut microbial metabolites may serve as a promising therapeutic strategy for PD. This article summarises all the known possible ways of bidirectional signal communication, i.e., the "gut-brain axis," where microbes from the middle gut interact with the brain and vice versa, and highlights a unique way to treat neurodegenerative diseases by maintaining homeostasis. The tenth cranial nerve (vagus nerve) plays a significant part in this signal communication. However, the leading regulatory factor for this axis is a diet that helps with microbial colonisation and brain function. Short-chain fatty acids (SCFAs), derived from microbially fermented dietary fibres, link host nutrition to maintain intestinal homeostasis. In addition to that, probiotics modulate cognitive function and the metabolic and behavioural conditions of the body. As technology advances, new techniques will emerge to study the tie-up between gut microbes and neuronal diseases.
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Affiliation(s)
- Ieshita Pan
- Institute of Biotechnology, Department of Medical Biotechnology and Integrative Physiology, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Thandalam, Chennai, Tamil Nadu, 602105, India.
| | - Praveen Kumar Issac
- Institute of Biotechnology, Department of Medical Biotechnology and Integrative Physiology, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Thandalam, Chennai, Tamil Nadu, 602105, India
| | - Md Mostafizur Rahman
- Laboratory of Environmental Health and Ecotoxicology, Department of Environmental Sciences, Jahangirnagar University, Dhaka, 1342, Bangladesh
| | - Ajay Guru
- Department of Cariology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, India.
| | - Jesu Arockiaraj
- Toxicology and Pharmacology Laboratory, Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur, Chengalpattu District, Tamil Nadu, 603203, India.
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Mezhibovsky E, Tveter KM, Villa-Rodriguez JA, Bacalia K, Kshatriya D, Desai N, Cabales A, Wu Y, Sui K, Duran RM, Bello NT, Roopchand DE. Grape Polyphenols May Prevent High-Fat Diet-Induced Dampening of the Hypothalamic-Pituitary-Adrenal Axis in Male Mice. J Endocr Soc 2023; 7:bvad095. [PMID: 37538101 PMCID: PMC10396072 DOI: 10.1210/jendso/bvad095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Indexed: 08/05/2023] Open
Abstract
Context Chronic high-fat diet (HFD) consumption causes obesity associated with retention of bile acids (BAs) that suppress important regulatory axes, such as the hypothalamic-pituitary-adrenal axis (HPAA). HFD impairs nutrient sensing and energy balance due to a dampening of the HPAA and reduced production and peripheral metabolism of corticosterone (CORT). Objective We assessed whether proanthocyanidin-rich grape polyphenol (GP) extract can prevent HFD-induced energy imbalance and HPAA dysregulation. Methods Male C57BL6/J mice were fed HFD or HFD supplemented with 0.5% w/w GPs (HFD-GP) for 17 weeks. Results GP supplementation reduced body weight gain and liver fat while increasing circadian rhythms of energy expenditure and HPAA-regulating hormones, CORT, leptin, and PYY. GP-induced improvements were accompanied by reduced mRNA levels of Il6, Il1b, and Tnfa in ileal or hepatic tissues and lower cecal abundance of Firmicutes, including known BA metabolizers. GP-supplemented mice had lower concentrations of circulating BAs, including hydrophobic and HPAA-inhibiting BAs, but higher cecal levels of taurine-conjugated BAs antagonistic to farnesoid X receptor (FXR). Compared with HFD-fed mice, GP-supplemented mice had increased mRNA levels of hepatic Cyp7a1 and Cyp27a1, suggesting reduced FXR activation and more BA synthesis. GP-supplemented mice also had reduced hepatic Abcc3 and ileal Ibabp and Ostβ, indicative of less BA transfer into enterocytes and circulation. Relative to HFD-fed mice, CORT and BA metabolizing enzymes (Akr1d1 and Srd5a1) were increased, and Hsd11b1 was decreased in GP supplemented mice. Conclusion GPs may attenuate HFD-induced weight gain by improving hormonal control of the HPAA and inducing a BA profile with less cytotoxicity and HPAA inhibition, but greater FXR antagonism.
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Affiliation(s)
- Esther Mezhibovsky
- Department of Food Science and NJ Institute for Food Nutrition and Health (Rutgers Center for Lipid Research; Center for Nutrition Microbiome and Health), Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
- Department of Nutritional Sciences Graduate Program, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Kevin M Tveter
- Department of Food Science and NJ Institute for Food Nutrition and Health (Rutgers Center for Lipid Research; Center for Nutrition Microbiome and Health), Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Jose A Villa-Rodriguez
- Department of Food Science and NJ Institute for Food Nutrition and Health (Rutgers Center for Lipid Research; Center for Nutrition Microbiome and Health), Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Karen Bacalia
- Department of Food Science and NJ Institute for Food Nutrition and Health (Rutgers Center for Lipid Research; Center for Nutrition Microbiome and Health), Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
- Department of Nutritional Sciences Graduate Program, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Dushyant Kshatriya
- Department of Nutritional Sciences Graduate Program, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
- Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Nikhil Desai
- Department of Food Science and NJ Institute for Food Nutrition and Health (Rutgers Center for Lipid Research; Center for Nutrition Microbiome and Health), Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Alrick Cabales
- Department of Food Science and NJ Institute for Food Nutrition and Health (Rutgers Center for Lipid Research; Center for Nutrition Microbiome and Health), Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Yue Wu
- Department of Food Science and NJ Institute for Food Nutrition and Health (Rutgers Center for Lipid Research; Center for Nutrition Microbiome and Health), Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Ke Sui
- Department of Food Science and NJ Institute for Food Nutrition and Health (Rutgers Center for Lipid Research; Center for Nutrition Microbiome and Health), Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Rocio M Duran
- Department of Food Science and NJ Institute for Food Nutrition and Health (Rutgers Center for Lipid Research; Center for Nutrition Microbiome and Health), Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Nicholas T Bello
- Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Diana E Roopchand
- Department of Food Science and NJ Institute for Food Nutrition and Health (Rutgers Center for Lipid Research; Center for Nutrition Microbiome and Health), Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
- Department of Nutritional Sciences Graduate Program, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
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Hartl L, Simbrunner B, Jachs M, Wolf P, Bauer DJM, Scheiner B, Balcar L, Semmler G, Schwarz M, Marculescu R, Trauner M, Mandorfer M, Reiberger T. An impaired pituitary-adrenal signalling axis in stable cirrhosis is linked to worse prognosis. JHEP Rep 2023; 5:100789. [PMID: 37484210 PMCID: PMC10362733 DOI: 10.1016/j.jhepr.2023.100789] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 05/01/2023] [Accepted: 05/04/2023] [Indexed: 07/25/2023] Open
Abstract
Background & Aims Inadequate adrenal function has been described in patients with cirrhosis. We investigated (i) the pituitary-adrenal axis at different clinical stages and (ii) the clinical impact of decreased serum cortisol levels in stable patients with advanced chronic liver disease (ACLD). Methods We included 137 outpatients with ACLD undergoing hepatic venous pressure gradient (HVPG) measurement in the prospective VICIS study (NCT03267615). Patients were stratified into six clinical stages: S0: subclinical portal hypertension (PH) (HVPG 6-9 mmHg), S1: clinically significant PH (HVPG ≥10 mmHg) without varices, S2: presence of varices, S3: previous variceal bleeding, S4: previous non-bleeding decompensation, and S5: further decompensation. Results Fifty-one patients had compensated ACLD (S0: n = 13; S1: n = 12; S2: n = 26), whereas 86 patients had decompensated ACLD (S3: n = 7; S4: n = 46; S5: n = 33). Serum total cortisol (t-Cort) showed a strong correlation with estimated serum free cortisol (f-Cort; Spearman's ρ: 0.889). With progressive clinical stage, median ACTH levels (from S0: 44.0 pg/ml to S5: 20.0 pg/ml; p = 0.006), t-Cort (from S0: 13.9 μg/dl to S5: 9.2 μg/dl; p = 0.091), and cortisol binding globulin (from S0: 49.3 μg/ml to S5: 38.9 μg/ml; p <0.001) decreased, whereas f-Cort (p = 0.474) remained unchanged. Lower t-Cort levels independently predicted bacterial infections (asHR: 1.11; 95% CI: 1.04-1.19; p = 0.002), further decompensation (asHR: 1.08; 95% CI: 1.02-1.12; p = 0.008), acute-on-chronic liver failure (ACLF; asHR: 1.11; 95% CI: 1.04-1.19; p = 0.002), and liver-related death (asHR: 1.09; 95% CI: 1.01-1.18; p = 0.045). Conclusions The pituitary-ACTH-adrenal-cortisol axis is progressively suppressed with increasing severity of cirrhosis. Lower t-Cort is an independent risk factor for bacterial infections, further decompensation of ACLF, and liver-related mortality-even in stable outpatients with cirrhosis. Clinical trial number Vienna Cirrhosis Study (VICIS; NCT: NCT03267615). Impact and Implications In a cohort of stable outpatients, we observed progressive suppression of the pituitary-adrenal axis with increasing clinical stage of advanced chronic liver disease (ACLD). Increased levels of bile acids and systemic inflammation (assessed by interleukin-6 levels) could be involved in this suppression. Serum total cortisol (t-Cort) was strongly correlated with serum free cortisol (f-Cort) and lower t-Cort levels were independently associated with a higher risk of adverse clinical outcomes, including bacterial infections, further decompensation, acute-on-chronic liver failure, and liver-related death.
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Affiliation(s)
- Lukas Hartl
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Vienna Hepatic Hemodynamic Lab, Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Benedikt Simbrunner
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Vienna Hepatic Hemodynamic Lab, Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Christian Doppler Lab for Portal Hypertension and Liver Fibrosis, Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Mathias Jachs
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Vienna Hepatic Hemodynamic Lab, Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Peter Wolf
- Division of Endocrinology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - David Josef Maria Bauer
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Vienna Hepatic Hemodynamic Lab, Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Bernhard Scheiner
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Vienna Hepatic Hemodynamic Lab, Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Lorenz Balcar
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Vienna Hepatic Hemodynamic Lab, Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Georg Semmler
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Vienna Hepatic Hemodynamic Lab, Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Michael Schwarz
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Vienna Hepatic Hemodynamic Lab, Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Rodrig Marculescu
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Michael Trauner
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Mattias Mandorfer
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Vienna Hepatic Hemodynamic Lab, Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Thomas Reiberger
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Vienna Hepatic Hemodynamic Lab, Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
- Christian Doppler Lab for Portal Hypertension and Liver Fibrosis, Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
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9
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Oteng AB, Liu L. GPCR-mediated effects of fatty acids and bile acids on glucose homeostasis. Front Endocrinol (Lausanne) 2023; 14:1206063. [PMID: 37484954 PMCID: PMC10360933 DOI: 10.3389/fendo.2023.1206063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 06/20/2023] [Indexed: 07/25/2023] Open
Abstract
Fatty acids and glucose are key biomolecules that share several commonalities including serving as energy substrates and as signaling molecules. Fatty acids can be synthesized endogenously from intermediates of glucose catabolism via de-novo lipogenesis. Bile acids are synthesized endogenously in the liver from the biologically important lipid molecule, cholesterol. Evidence abounds that fatty acids and bile acids play direct and indirect roles in systemic glucose homeostasis. The tight control of plasma glucose levels during postprandial and fasted states is principally mediated by two pancreatic hormones, insulin and glucagon. Here, we summarize experimental studies on the endocrine effects of fatty acids and bile acids, with emphasis on their ability to regulate the release of key hormones that regulate glucose metabolism. We categorize the heterogenous family of fatty acids into short chain fatty acids (SCFAs), unsaturated, and saturated fatty acids, and highlight that along with bile acids, these biomolecules regulate glucose homeostasis by serving as endogenous ligands for specific G-protein coupled receptors (GPCRs). Activation of these GPCRs affects the release of incretin hormones by enteroendocrine cells and/or the secretion of insulin, glucagon, and somatostatin by pancreatic islets, all of which regulate systemic glucose homeostasis. We deduce that signaling induced by fatty acids and bile acids is necessary to maintain euglycemia to prevent metabolic diseases such as type-2 diabetes and related metabolic disorders.
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10
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Rusch JA, Layden BT, Dugas LR. Signalling cognition: the gut microbiota and hypothalamic-pituitary-adrenal axis. Front Endocrinol (Lausanne) 2023; 14:1130689. [PMID: 37404311 PMCID: PMC10316519 DOI: 10.3389/fendo.2023.1130689] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 05/25/2023] [Indexed: 07/06/2023] Open
Abstract
Cognitive function in humans depends on the complex and interplay between multiple body systems, including the hypothalamic-pituitary-adrenal (HPA) axis. The gut microbiota, which vastly outnumbers human cells and has a genetic potential that exceeds that of the human genome, plays a crucial role in this interplay. The microbiota-gut-brain (MGB) axis is a bidirectional signalling pathway that operates through neural, endocrine, immune, and metabolic pathways. One of the major neuroendocrine systems responding to stress is the HPA axis which produces glucocorticoids such as cortisol in humans and corticosterone in rodents. Appropriate concentrations of cortisol are essential for normal neurodevelopment and function, as well as cognitive processes such as learning and memory, and studies have shown that microbes modulate the HPA axis throughout life. Stress can significantly impact the MGB axis via the HPA axis and other pathways. Animal research has advanced our understanding of these mechanisms and pathways, leading to a paradigm shift in conceptual thinking about the influence of the microbiota on human health and disease. Preclinical and human trials are currently underway to determine how these animal models translate to humans. In this review article, we summarize the current knowledge of the relationship between the gut microbiota, HPA axis, and cognition, and provide an overview of the main findings and conclusions in this broad field.
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Affiliation(s)
- Jody A. Rusch
- Division of Chemical Pathology, Department of Pathology, University of Cape Town, Cape Town, South Africa
- C17 Chemical Pathology Laboratory, Groote Schuur Hospital, National Health Laboratory Service, Cape Town, South Africa
| | - Brian T. Layden
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, IL, United States
- Department of Medicine, Jesse Brown Veterans Affairs Medical Center, Chicago, IL, United States
| | - Lara R. Dugas
- Division of Epidemiology and Biostatistics, School of Public Health, University of Cape Town, Cape Town, South Africa
- Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University Chicago, Maywood, IL, United States
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11
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Xing C, Huang X, Wang D, Yu D, Hou S, Cui H, Song L. Roles of bile acids signaling in neuromodulation under physiological and pathological conditions. Cell Biosci 2023; 13:106. [PMID: 37308953 PMCID: PMC10258966 DOI: 10.1186/s13578-023-01053-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/13/2023] [Indexed: 06/14/2023] Open
Abstract
Bile acids (BA) are important physiological molecules not only mediating nutrients absorption and metabolism in peripheral tissues, but exerting neuromodulation effect in the central nerve system (CNS). The catabolism of cholesterol to BA occurs predominantly in the liver by the classical and alternative pathways, or in the brain initiated by the neuronal-specific enzyme CYP46A1 mediated pathway. Circulating BA could cross the blood brain barrier (BBB) and reach the CNS through passive diffusion or BA transporters. Brain BA might trigger direct signal through activating membrane and nucleus receptors or affecting activation of neurotransmitter receptors. Peripheral BA may also provide the indirect signal to the CNS via farnesoid X receptor (FXR) dependent fibroblast growth factor 15/19 (FGF15/19) pathway or takeda G protein coupled receptor 5 (TGR5) dependent glucagon-like peptide-1 (GLP-1) pathway. Under pathological conditions, alterations in BA metabolites have been discovered as potential pathogenic contributors in multiple neurological disorders. Attractively, hydrophilic ursodeoxycholic acid (UDCA), especially tauroursodeoxycholic acid (TUDCA) can exert neuroprotective roles by attenuating neuroinflammation, apoptosis, oxidative or endoplasmic reticulum stress, which provides promising therapeutic effects for treatment of neurological diseases. This review summarizes recent findings highlighting the metabolism, crosstalk between brain and periphery, and neurological functions of BA to elucidate the important role of BA signaling in the brain under both physiological and pathological conditions.
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Affiliation(s)
- Chen Xing
- Beijing Institute of Basic Medical Sciences, Taiping Road #27, Beijing, 100850, China.
| | - Xin Huang
- Beijing Institute of Basic Medical Sciences, Taiping Road #27, Beijing, 100850, China
| | - Dongxue Wang
- Beijing Institute of Basic Medical Sciences, Taiping Road #27, Beijing, 100850, China
- College of Pharmacy, Jiamusi University, Jiamusi, 154007, China
| | - Dengjun Yu
- Beijing Institute of Basic Medical Sciences, Taiping Road #27, Beijing, 100850, China
- College of Pharmacy, Jiamusi University, Jiamusi, 154007, China
| | - Shaojun Hou
- Beijing Institute of Basic Medical Sciences, Taiping Road #27, Beijing, 100850, China
- Anhui Medical University, Heifei, 230032, China
| | - Haoran Cui
- Beijing Institute of Basic Medical Sciences, Taiping Road #27, Beijing, 100850, China
| | - Lung Song
- Beijing Institute of Basic Medical Sciences, Taiping Road #27, Beijing, 100850, China.
- Anhui Medical University, Heifei, 230032, China.
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12
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Zhai W, Zhang T, Jin Y, Huang S, Xu M, Pan J. The fibroblast growth factor system in cognitive disorders and dementia. Front Neurosci 2023; 17:1136266. [PMID: 37214403 PMCID: PMC10196031 DOI: 10.3389/fnins.2023.1136266] [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: 01/02/2023] [Accepted: 04/19/2023] [Indexed: 05/24/2023] Open
Abstract
Cognitive impairment is the core precursor to dementia and other cognitive disorders. Current hypotheses suggest that they share a common pathological basis, such as inflammation, restricted neurogenesis, neuroendocrine disorders, and the destruction of neurovascular units. Fibroblast growth factors (FGFs) are cell growth factors that play essential roles in various pathophysiological processes via paracrine or autocrine pathways. This system consists of FGFs and their receptors (FGFRs), which may hold tremendous potential to become a new biological marker in the diagnosis of dementia and other cognitive disorders, and serve as a potential target for drug development against dementia and cognitive function impairment. Here, we review the available evidence detailing the relevant pathways mediated by multiple FGFs and FGFRs, and recent studies examining their role in the pathogenesis and treatment of cognitive disorders and dementia.
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13
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Romanazzi T, Zanella D, Bhatt M, Di Iacovo A, Galli A, Bossi E. Bile acid interactions with neurotransmitter transporters. Front Cell Neurosci 2023; 17:1161930. [PMID: 37180953 PMCID: PMC10169653 DOI: 10.3389/fncel.2023.1161930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 04/11/2023] [Indexed: 05/16/2023] Open
Abstract
Synthesized in the liver from cholesterol, the bile acids (BAs) primary role is emulsifying fats to facilitate their absorption. BAs can cross the blood-brain barrier (BBB) and be synthesized in the brain. Recent evidence suggests a role for BAs in the gut-brain signaling by modulating the activity of various neuronal receptors and transporters, including the dopamine transporter (DAT). In this study, we investigated the effects of BAs and their relationship with substrates in three transporters of the solute carrier 6 family. The exposure to obeticholic acid (OCA), a semi-synthetic BA, elicits an inward current (IBA) in the DAT, the GABA transporter 1 (GAT1), and the glycine transporter 1 (GlyT1b); this current is proportional to the current generated by the substrate, respective to the transporter. Interestingly, a second consecutive OCA application to the transporter fails to elicit a response. The full displacement of BAs from the transporter occurs only after exposure to a saturating concentration of a substrate. In DAT, perfusion of secondary substrates norepinephrine (NE) and serotonin (5-HT) results in a second OCA current, decreased in amplitude and proportional to their affinity. Moreover, co-application of 5-HT or NE with OCA in DAT, and GABA with OCA in GAT1, did not alter the apparent affinity or the Imax, similar to what was previously reported in DAT in the presence of DA and OCA. The findings support the previous molecular model that suggested the ability of BAs to lock the transporter in an occluded conformation. The physiological significance is that it could possibly avoid the accumulation of small depolarizations in the cells expressing the neurotransmitter transporter. This achieves better transport efficiency in the presence of a saturating concentration of the neurotransmitter and enhances the action of the neurotransmitter on their receptors when they are present at reduced concentrations due to decreased availability of transporters.
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Affiliation(s)
- Tiziana Romanazzi
- Laboratory of Cellular and Molecular Physiology, Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- Ph.D. School in Experimental and Translational Medicine, University of Insubria, Varese, Italy
| | - Daniele Zanella
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Manan Bhatt
- Laboratory of Cellular and Molecular Physiology, Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- Ph.D. School in Experimental and Translational Medicine, University of Insubria, Varese, Italy
| | - Angela Di Iacovo
- Laboratory of Cellular and Molecular Physiology, Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- Ph.D. School in Experimental and Translational Medicine, University of Insubria, Varese, Italy
| | - Aurelio Galli
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Elena Bossi
- Laboratory of Cellular and Molecular Physiology, Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- Center for Research in Neuroscience, University of Insubria, Varese, Italy
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14
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Li J, Zhang F, Zhao L, Dong C. Microbiota-gut-brain axis and related therapeutics in Alzheimer's disease: prospects for multitherapy and inflammation control. Rev Neurosci 2023:revneuro-2023-0006. [PMID: 37076953 DOI: 10.1515/revneuro-2023-0006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 03/26/2023] [Indexed: 04/21/2023]
Abstract
Alzheimer's disease (AD) is the most common type of dementia in the elderly and causes neurodegeneration, leading to memory loss, behavioral disorder, and psychiatric impairment. One potential mechanism contributing to the pathogenesis of AD may be the imbalance in gut microbiota, local and systemic inflammation, and dysregulation of the microbiota-gut-brain axis (MGBA). Most of the AD drugs approved for clinical use today are symptomatic treatments that do not improve AD pathologic changes. As a result, researchers are exploring novel therapeutic modalities. Treatments involving the MGBA include antibiotics, probiotics, transplantation of fecal microbiota, botanical products, and others. However, single-treatment modalities are not as effective as expected, and a combination therapy is gaining momentum. The purpose of this review is to summarize recent advances in MGBA-related pathological mechanisms and treatment modalities in AD and to propose a new concept of combination therapy. "MGBA-based multitherapy" is an emerging view of treatment in which classic symptomatic treatments and MGBA-based therapeutic modalities are used in combination. Donepezil and memantine are two commonly used drugs in AD treatment. On the basis of the single/combined use of these two drugs, two/more additional drugs and treatment modalities that target the MGBA are chosen based on the characteristics of the patient's condition as an adjuvant treatment, as well as the maintenance of good lifestyle habits. "MGBA-based multitherapy" offers new insights for the treatment of cognitive impairment in AD patients and is expected to show good therapeutic results.
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Affiliation(s)
- Jiahao Li
- Department of Neurology, The First Affiliated Hospital, Dalian Medical University, No. 222 Zhongshan Road, Dalian 116011, China
| | - Feng Zhang
- Department of Neurology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Li Zhao
- Department of Neurology, The First Affiliated Hospital, Dalian Medical University, No. 222 Zhongshan Road, Dalian 116011, China
| | - Chunbo Dong
- Department of Neurology, The First Affiliated Hospital, Dalian Medical University, No. 222 Zhongshan Road, Dalian 116011, China
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15
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Sivcev S, Kudova E, Zemkova H. Neurosteroids as positive and negative allosteric modulators of ligand-gated ion channels: P2X receptor perspective. Neuropharmacology 2023; 234:109542. [PMID: 37040816 DOI: 10.1016/j.neuropharm.2023.109542] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 03/06/2023] [Accepted: 04/07/2023] [Indexed: 04/13/2023]
Abstract
Neurosteroids are steroids synthesized de novo in the brain from cholesterol in an independent manner from peripheral steroid sources. The term "neuroactive steroid" includes all steroids independent of their origin, and newly synthesized analogs of neurosteroids that modify neuronal activities. In vivo application of neuroactive steroids induces potent anxiolytic, antidepressant, anticonvulsant, sedative, analgesic and amnesic effects, mainly through interaction with the γ-aminobutyric acid type-A receptor (GABAAR). However, neuroactive steroids also act as positive or negative allosteric regulators on several ligand-gated channels including N-methyl-d-aspartate receptors (NMDARs), nicotinic acetylcholine receptors (nAChRs) and ATP-gated purinergic P2X receptors. Seven different P2X subunits (P2X1-7) can assemble to form homotrimeric or heterotrimeric ion channels permeable for monovalent cations and calcium. Among them, P2X2, P2X4, and P2X7 are the most abundant within the brain and can be regulated by neurosteroids. Transmembrane domains are necessary for neurosteroid binding, however, no generic motif of amino acids can accurately predict the neurosteroid binding site for any of the ligand-gated ion channels including P2X. Here, we will review what is currently known about the modulation of rat and human P2X by neuroactive steroids and the possible structural determinants underlying neurosteroid-induced potentiation and inhibition of the P2X2 and P2X4 receptors.
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Affiliation(s)
- Sonja Sivcev
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic; Faculty of Science, Charles University, Prague, Czech Republic
| | - Eva Kudova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Hana Zemkova
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
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16
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Ehtezazi T, Rahman K, Davies R, Leach AG. The Pathological Effects of Circulating Hydrophobic Bile Acids in Alzheimer's Disease. J Alzheimers Dis Rep 2023; 7:173-211. [PMID: 36994114 PMCID: PMC10041467 DOI: 10.3233/adr-220071] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
Recent clinical studies have revealed that the serum levels of toxic hydrophobic bile acids (deoxy cholic acid, lithocholic acid [LCA], and glycoursodeoxycholic acid) are significantly higher in patients with Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) when compared to control subjects. The elevated serum bile acids may be the result of hepatic peroxisomal dysfunction. Circulating hydrophobic bile acids are able to disrupt the blood-brain barrier and promote the formation of amyloid-β plaques through enhancing the oxidation of docosahexaenoic acid. Hydrophobic bile acid may find their ways into the neurons via the apical sodium-dependent bile acid transporter. It has been shown that hydrophobic bile acids impose their pathological effects by activating farnesoid X receptor and suppressing bile acid synthesis in the brain, blocking NMDA receptors, lowering brain oxysterol levels, and interfering with 17β-estradiol actions such as LCA by binding to E2 receptors (molecular modelling data exclusive to this paper). Hydrophobic bile acids may interfere with the sonic hedgehog signaling through alteration of cell membrane rafts and reducing brain 24(S)-hydroxycholesterol. This article will 1) analyze the pathological roles of circulating hydrophobic bile acids in the brain, 2) propose therapeutic approaches, and 3) conclude that consideration be given to reducing/monitoring toxic bile acid levels in patients with AD or aMCI, prior/in combination with other treatments.
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Affiliation(s)
- Touraj Ehtezazi
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
| | - Khalid Rahman
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
| | - Rhys Davies
- The Walton Centre, NHS Foundation Trust, Liverpool, UK
| | - Andrew G Leach
- School of Pharmacy, University of Manchester, Manchester, UK
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17
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Ren ZL, Li CX, Ma CY, Chen D, Chen JH, Xu WX, Chen CA, Cheng FF, Wang XQ. Linking Nonalcoholic Fatty Liver Disease and Brain Disease: Focusing on Bile Acid Signaling. Int J Mol Sci 2022; 23:13045. [PMID: 36361829 PMCID: PMC9654021 DOI: 10.3390/ijms232113045] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/21/2022] [Accepted: 10/25/2022] [Indexed: 11/01/2023] Open
Abstract
A metabolic illness known as non-alcoholic fatty liver disease (NAFLD), affects more than one-quarter of the world's population. Bile acids (BAs), as detergents involved in lipid digestion, show an abnormal metabolism in patients with NAFLD. However, BAs can affect other organs as well, such as the brain, where it has a neuroprotective effect. According to a series of studies, brain disorders may be extrahepatic manifestations of NAFLD, such as depression, changes to the cerebrovascular system, and worsening cognitive ability. Consequently, we propose that NAFLD affects the development of brain disease, through the bile acid signaling pathway. Through direct or indirect channels, BAs can send messages to the brain. Some BAs may operate directly on the central Farnesoid X receptor (FXR) and the G protein bile acid-activated receptor 1 (GPBAR1) by overcoming the blood-brain barrier (BBB). Furthermore, glucagon-like peptide-1 (GLP-1) and the fibroblast growth factor (FGF) 19 are released from the intestine FXR and GPBAR1 receptors, upon activation, both of which send signals to the brain. Inflammatory, systemic metabolic disorders in the liver and brain are regulated by the bile acid-activated receptors FXR and GPBAR1, which are potential therapeutic targets. From a bile acid viewpoint, we examine the bile acid signaling changes in NAFLD and brain disease. We also recommend the development of dual GPBAR1/FXR ligands to reduce side effects and manage NAFLD and brain disease efficiently.
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Affiliation(s)
- Zi-Lin Ren
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Chang-Xiang Li
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Chong-Yang Ma
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China
| | - Dan Chen
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Jia-Hui Chen
- Dongzhimen Hospital, Beijing University of Traditional Chinese Medicine, Beijing 100700, China
| | - Wen-Xiu Xu
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Cong-Ai Chen
- Dongzhimen Hospital, Beijing University of Traditional Chinese Medicine, Beijing 100700, China
| | - Fa-Feng Cheng
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Xue-Qian Wang
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029, China
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18
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Hammond TC, Powell E, Green SJ, Chlipala G, Frank J, Yackzan AT, Yanckello LM, Chang YH, Xing X, Heil S, Springer JE, Pennypacker K, Stromberg A, Sawaki L, Lin AL. Functional recovery outcomes following acute stroke is associated with abundance of gut microbiota related to inflammation, butyrate and secondary bile acid. FRONTIERS IN REHABILITATION SCIENCES 2022; 3:1017180. [PMID: 36386777 PMCID: PMC9644110 DOI: 10.3389/fresc.2022.1017180] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/04/2022] [Indexed: 11/23/2022]
Abstract
Accumulating evidence suggests that gut microbes modulate brain plasticity via the bidirectional gut-brain axis and play a role in stroke rehabilitation. However, the microbial species alterations associated with stroke and their correlation with functional outcome measures following acute stroke remain unknown. Here we measure post-stroke gut dysbiosis and how it correlates with gut permeability and cognitive functions in 12 stroke participants, 18 controls with risk factors for stroke, and 12 controls without risk factors. Stool samples were used to measure the microbiome with whole genome shotgun sequencing and leaky gut markers. We genotyped APOE status and measured diet composition and motor, cognitive, and emotional status using NIH Toolbox. We used linear regression methods to identify gut microbial associations with cognitive and emotional assessments. We did not find significance differences between the two control groups. In contrast, the bacteria populations of the Stroke group were statistically dissimilar from the control groups. Relative abundance analysis revealed notable decreases in butyrate-producing microbial taxa, secondary bile acid-producing taxa, and equol-producing taxa. The Stroke group had higher levels of the leaky gut marker alpha-1-antitrypsin in the stool than either of the groups and several taxa including Roseburia species (a butyrate producer) were negatively correlated with alpha-1-antitrypsin. Stroke participants scored lower on memory testing than those in the two control groups. Stroke participants with more Roseburia performed better on the picture vocabulary task; more Bacteroides uniformis (a butyrate producer) and less Escherichia coli (a pro-inflammatory species) reported higher levels of self-efficacy. Intakes of fiber, fruit and vegetable were lower, but sweetened beverages were higher, in the Stroke group compared with controls. Vegetable consumption was correlated with many bacterial changes among the participants, but only the species Clostridium bolteae, a pro-inflammatory species, was significantly associated with stroke. Our findings indicate that stroke is associated with a higher abundance of proinflammatory species and a lower abundance of butyrate producers and secondary bile acid producers. These altered microbial communities are associated with poorer functional performances. Future studies targeting the gut microbiome should be developed to elucidate whether its manipulation could optimize rehabilitation and boost recovery.
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Affiliation(s)
- Tyler C. Hammond
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
- Department of Neuroscience, University of Kentucky, Lexington, KY, United States
| | - Elizabeth Powell
- Department of Physical Medicine and Rehabilitation, University of Kentucky, Lexington, KY, United States
| | - Stefan J. Green
- Genomics and Microbiome Core Facility, Rush University, Chicago, IL, United States
| | - George Chlipala
- Research Informatics Core, University of Illinois Chicago, Chicago, IL, United States
| | - Jacqueline Frank
- Department of Neuroscience, University of Kentucky, Lexington, KY, United States
- Center for Advanced Stroke Science, Department of Neurology, University of Kentucky, Lexington, KY, United States
| | - Andrew T. Yackzan
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - Lucille M. Yanckello
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, United States
| | - Ya-Hsuan Chang
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, United States
| | - Xin Xing
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
- Department of Computer Science, University of Kentucky, Lexington, KY, United States
| | - Sally Heil
- School of Medicine, University of Missouri, Columbia, MO, United States
| | - Joe E. Springer
- Department of Neuroscience, University of Kentucky, Lexington, KY, United States
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, United States
| | - Keith Pennypacker
- Department of Neuroscience, University of Kentucky, Lexington, KY, United States
- Center for Advanced Stroke Science, Department of Neurology, University of Kentucky, Lexington, KY, United States
| | - Arnold Stromberg
- Department of Statistics, University of Kentucky, Lexington, KY, United States
| | - Lumy Sawaki
- Department of Physical Medicine and Rehabilitation, University of Kentucky, Lexington, KY, United States
| | - Ai-Ling Lin
- Department of Radiology, University of Missouri, Columbia, MO, United States
- Institute for Data Science & Informatics, University of Missouri, Columbia, MOUnited States
- Department of Biological Sciences, University of Missouri, Columbia, MO, United States
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19
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Adrenal histological and functional changes after hepatic encephalopathy: From mice model to an integrative bioinformatics analysis. Acta Histochem 2022; 124:151960. [DOI: 10.1016/j.acthis.2022.151960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 09/28/2022] [Indexed: 11/15/2022]
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20
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Lirong W, Mingliang Z, Mengci L, Qihao G, Zhenxing R, Xiaojiao Z, Tianlu C. The clinical and mechanistic roles of bile acids in depression, Alzheimer's disease, and stroke. Proteomics 2022; 22:e2100324. [PMID: 35731901 DOI: 10.1002/pmic.202100324] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 05/31/2022] [Accepted: 06/15/2022] [Indexed: 10/17/2022]
Abstract
The burden of neurological and neuropsychiatric disorders continues to grow with significant impacts on human health and social economy worldwide. Increasing clinical and preclinical evidences have implicated that bile acids (BAs) are involved in the onset and progression of neurological and neuropsychiatric diseases. Here, we summarized recent studies of BAs in three types of highly prevalent brain disorders, depression, Alzheimer's disease, and stroke. The shared and specific BA profiles were explored and potential markers associated with disease development and progression were summarized. The mechanistic roles of BAs were reviewed with focuses on inflammation, gut-brain-microbiota axis, cellular apoptosis. We also discussed future perspectives for the prevention and treatment of neurological and neuropsychiatric disorders by targeting BAs and related molecules and gut microbiota. Our understanding of BAs and their roles in brain disorders is still evolving. A large number of questions still need to be addressed on the emerging crosstalk among central, peripheral, intestine and their contribution to brain and mental health. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Wu Lirong
- Center for Translational Medicine and Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Zhao Mingliang
- Center for Translational Medicine and Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Li Mengci
- Center for Translational Medicine and Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Guo Qihao
- Department of gerontology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Ren Zhenxing
- Center for Translational Medicine and Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Zheng Xiaojiao
- Center for Translational Medicine and Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Chen Tianlu
- Center for Translational Medicine and Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
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21
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Vegas-Suárez S, Simón J, Martínez-Chantar ML, Moratalla R. Metabolic Diffusion in Neuropathologies: The Relevance of Brain-Liver Axis. Front Physiol 2022; 13:864263. [PMID: 35634148 PMCID: PMC9134112 DOI: 10.3389/fphys.2022.864263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/25/2022] [Indexed: 11/10/2022] Open
Abstract
Chronic liver diseases include a broad group of hepatic disorders from different etiologies and with varying degrees of progression and severity. Among them, non-alcoholic fatty (NAFLD) and alcoholic (ALD) liver diseases are the most frequent forms of expression, caused by either metabolic alterations or chronic alcohol consumption. The liver is the main regulator of energy homeostasis and metabolism of potentially toxic compounds in the organism, thus hepatic disorders often promote the release of harmful substances. In this context, there is an existing interconnection between liver and brain, with the well-named brain-liver axis, in which liver pathologies lead to the promotion of neurodegenerative disorders. Alzheimer's (AD) and Parkinson's (PD) diseases are the most relevant neurological disorders worldwide. The present work highlights the relevance of the liver-related promotion of these disorders. Liver-related hyperammonemia has been related to the promotion of perturbations in nervous systems, whereas the production of ketone bodies under certain conditions may protect from developing them. The capacity of the liver of amyloid-β (Aβ) clearance is reduced under liver pathologies, contributing to the development of AD. These perturbations are even aggravated by the pro-inflammatory state that often accompanies liver diseases, leading to the named neuroinflammation. The current nourishment habits, named as Western diet (WD) and alterations in the bile acid (BA) profile, whose homeostasis is controlled by the liver, have been also related to both AD and PD, whereas the supplementation with certain compounds, has been demonstrated to alleviate the pathologies.
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Affiliation(s)
- Sergio Vegas-Suárez
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), Leioa, Spain,Cajal Institute, Spanish National Research Council (CSIC), Madrid, Spain,Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERned), Carlos III Institute of Health (ISCIII), Madrid, Spain
| | - Jorge Simón
- Liver Disease Lab, Center for Cooperative Research in Biosciences (CIC BioGUNE), Basque Research and Technology Alliance (BRTA), Derio, Spain,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Carlos III Institute of Health (ISCIII), Madrid, Spain
| | - María Luz Martínez-Chantar
- Liver Disease Lab, Center for Cooperative Research in Biosciences (CIC BioGUNE), Basque Research and Technology Alliance (BRTA), Derio, Spain,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Carlos III Institute of Health (ISCIII), Madrid, Spain,*Correspondence: María Luz Martínez-Chantar, ; Rosario Moratalla,
| | - Rosario Moratalla
- Cajal Institute, Spanish National Research Council (CSIC), Madrid, Spain,Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERned), Carlos III Institute of Health (ISCIII), Madrid, Spain,*Correspondence: María Luz Martínez-Chantar, ; Rosario Moratalla,
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22
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A critical review of bile acids and their receptors in hepatic encephalopathy. Anal Biochem 2022; 643:114436. [PMID: 34715070 PMCID: PMC9798441 DOI: 10.1016/j.ab.2021.114436] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 09/15/2021] [Accepted: 10/22/2021] [Indexed: 01/01/2023]
Abstract
Hepatic encephalopathy describes an array of neurological complications that arise due to liver insufficiency. The pathogenesis of hepatic encephalopathy shares a longstanding association with hyperammonemia and inflammation, and recently, aberrant bile acid signaling has been implicated in the development of key features of hepatic encephalopathy. These key features include neuronal dysfunction, neuroinflammation and blood-brain barrier permeability. This review summarizes the findings of recent studies demonstrating a role for bile acids in the pathogenesis of hepatic encephalopathy via one of three main bile acid receptors and speculates on the possible downstream consequences of aberrant bile acid signaling.
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23
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Joyce SA, O'Malley D. Bile acids, bioactive signalling molecules in interoceptive gut-to-brain communication. J Physiol 2022; 600:2565-2578. [PMID: 35413130 PMCID: PMC9325455 DOI: 10.1113/jp281727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 04/07/2022] [Indexed: 11/08/2022] Open
Abstract
Aside from facilitating solubilisation and absorption of dietary lipids and lipid-soluble vitamins, amphipathic bile acids (BAs) also act as bioactive signalling molecules. A plethora of conjugated or un-conjugated primary and bacterially-modified secondary BA moieties have been identified, with significant divergence between species. These molecules are excreted into the external environment of the intestinal lumen, yet nuclear and membrane receptors that are sensitive to BAs are expressed internally in the liver, intestinal and neural tissues, amongst others. The diversity of BAs and receptors underpins the multitude of distinct bioactive functions attributed to BAs, but also hampers elucidation of the physiological mechanisms underpinning these actions. In this topical review, we have considered the potential of BAs as cross-barrier signalling molecules that contribute to interoceptive pathways informing the central nervous system of environmental changes in the gut lumen. Activation of BAs on FGF19 -secreting enterocytes, enteroendocrine cells coupled to sensory nerves or intestinal immune cells would facilitate indirect signalling, whereas direct activation of BA receptors in the brain are likely to occur primarily under pathophysiological conditions when concentrations of BAs are elevated. Abstract figure legend The figure illustrates the microbial modification of hepatic primary bile acids into secondary bile acids. In addition to facilitating lipid digestion and absorption, bile acids act as bioactive signalling molecules by binding to bile acid receptors expressed on enterocytes, neural afferent-coupled enteroendocrine cells and immune cells. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Susan A Joyce
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Dervla O'Malley
- APC Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Physiology, College of Medicine and Health, University College Cork, Cork, Ireland
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24
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Neurohormonal Changes in the Gut–Brain Axis and Underlying Neuroendocrine Mechanisms following Bariatric Surgery. Int J Mol Sci 2022; 23:ijms23063339. [PMID: 35328759 PMCID: PMC8954280 DOI: 10.3390/ijms23063339] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 02/05/2023] Open
Abstract
Obesity is a complex, multifactorial disease that is a major public health issue worldwide. Currently approved anti-obesity medications and lifestyle interventions lack the efficacy and durability needed to combat obesity, especially in individuals with more severe forms or coexisting metabolic disorders, such as poorly controlled type 2 diabetes. Bariatric surgery is considered an effective therapeutic modality with sustained weight loss and metabolic benefits. Numerous genetic and environmental factors have been associated with the pathogenesis of obesity, while cumulative evidence has highlighted the gut–brain axis as a complex bidirectional communication axis that plays a crucial role in energy homeostasis. This has led to increased research on the roles of neuroendocrine signaling pathways and various gastrointestinal peptides as key mediators of the beneficial effects following weight-loss surgery. The accumulate evidence suggests that the development of gut-peptide-based agents can mimic the effects of bariatric surgery and thus is a highly promising treatment strategy that could be explored in future research. This article aims to elucidate the potential underlying neuroendocrine mechanisms of the gut–brain axis and comprehensively review the observed changes of gut hormones associated with bariatric surgery. Moreover, the emerging role of post-bariatric gut microbiota modulation is briefly discussed.
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25
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Weng ZB, Chen YR, Lv JT, Wang MX, Chen ZY, Zhou W, Shen XC, Zhan LB, Wang F. A Review of Bile Acid Metabolism and Signaling in Cognitive Dysfunction-Related Diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:4289383. [PMID: 35308170 PMCID: PMC8933076 DOI: 10.1155/2022/4289383] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/14/2021] [Accepted: 02/23/2022] [Indexed: 12/12/2022]
Abstract
Bile acids are commonly known as one of the vital metabolites derived from cholesterol. The role of bile acids in glycolipid metabolism and their mechanisms in liver and cholestatic diseases have been well studied. In addition, bile acids also serve as ligands of signal molecules such as FXR, TGR5, and S1PR2 to regulate some physiological processes in vivo. Recent studies have found that bile acids signaling may also play a critical role in the central nervous system. Evidence showed that some bile acids have exhibited neuroprotective effects in experimental animal models and clinical trials of many cognitive dysfunction-related diseases. Besides, alterations in bile acid metabolisms well as the expression of different bile acid receptors have been discovered as possible biomarkers for prognosis tools in multiple cognitive dysfunction-related diseases. This review summarizes biosynthesis and regulation of bile acids, receptor classification and characteristics, receptor agonists and signaling transduction, and recent findings in cognitive dysfunction-related diseases.
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Affiliation(s)
- Ze-Bin Weng
- School of Traditional Chinese Medicine & School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yuan-Rong Chen
- College of Food Science and Engineering/Collaborative Innovation Center for Modern Grain Circulation and Safety/Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing, China
| | - Jin-Tao Lv
- School of Traditional Chinese Medicine & School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Min-Xin Wang
- School of Traditional Chinese Medicine & School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Zheng-Yuan Chen
- School of Traditional Chinese Medicine & School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Wen Zhou
- School of Traditional Chinese Medicine & School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Xin-Chun Shen
- College of Food Science and Engineering/Collaborative Innovation Center for Modern Grain Circulation and Safety/Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing, China
| | - Li-Bin Zhan
- The Innovation Engineering Technology Center of Chinese Medicine, Liaoning University of Traditional Chinese Medicine, Shenyang, China
| | - Fang Wang
- College of Food Science and Engineering/Collaborative Innovation Center for Modern Grain Circulation and Safety/Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing, China
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26
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Jiang S, Hu Q, Zhang J. Dexamethasone may affect the occurrence of parenteral nutrition-associated cholestasis in preterm neonates. Front Pediatr 2022; 10:1023798. [PMID: 36568435 PMCID: PMC9772609 DOI: 10.3389/fped.2022.1023798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 11/23/2022] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION Glucocorticoids are currently used for the co-therapeutic management of autoimmune hepatitis and some cholestatic diseases. Thus far, we do not know the efficacy of glucocorticoids in the treatment of parenteral nutrition-associated cholestasis. We aimed to analyze whether the administration of late postnatal dexamethasone for treating bronchopulmonary dysplasia influence the occurrence of parenteral nutrition-associated cholestasis in preterm neonates. METHODS A retrospective study was conducted for 78 preterm neonates without major anomalies (gestational age was <30 weeks, and birthweight was ≤1000 g) hospitalized in a neonatal unit. Total and direct serum bilirubin levels were measured about every two weeks for all neonates. Data including the administration of dexamethasone, intravenous nutrition, and enteral feeding were collected by at least three audits. RESULTS A total of 15 preterm neonates were diagnosed with parenteral nutrition-associated cholestasis, and after stopping parenteral nutrition, the direct bilirubin value decreased to the normal level for no longer than 150 days. The prolonged duration of parenteral nutrition was a risk factor, and late postnatal dexamethasone treatment was a protective factor in reducing the incidence of parenteral nutrition-associated cholestasis. CONCLUSION Dexamethasone treatment may reduce the occurrence of parenteral nutrition-associated cholestasis in preterm neonates.
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Affiliation(s)
- Saizhi Jiang
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Qingqing Hu
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jing Zhang
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
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27
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So SY, Savidge TC. Gut feelings: the microbiota-gut-brain axis on steroids. Am J Physiol Gastrointest Liver Physiol 2022; 322:G1-G20. [PMID: 34730020 PMCID: PMC8698538 DOI: 10.1152/ajpgi.00294.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/26/2021] [Accepted: 10/29/2021] [Indexed: 01/31/2023]
Abstract
The intricate connection between central and enteric nervous systems is well established with emerging evidence linking gut microbiota function as a significant new contributor to gut-brain axis signaling. Several microbial signals contribute to altered gut-brain communications, with steroids representing an important biological class that impacts central and enteric nervous system function. Neuroactive steroids contribute pathologically to neurological disorders, including dementia and depression, by modulating the activity of neuroreceptors. However, limited information is available on the influence of neuroactive steroids on the enteric nervous system and gastrointestinal function. In this review, we outline how steroids can modulate enteric nervous system function by focusing on their influence on different receptors that are present in the intestine in health and disease. We also highlight the potential role of the gut microbiota in modulating neuroactive steroid signaling along the gut-brain axis.
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Affiliation(s)
- Sik Yu So
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas
| | - Tor C Savidge
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas
- Department of Pathology, Texas Children's Microbiome Center, Texas Children's Hospital, Houston, Texas
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28
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Bile acid-permeation enhancement for inner ear cochlear drug - pharmacological uptake: bio-nanotechnologies in chemotherapy-induced hearing loss. Ther Deliv 2021; 12:807-819. [PMID: 34761700 DOI: 10.4155/tde-2021-0048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Ototoxicity is the damage to inner ear sensory epithelia due to exposure to certain medications and chemicals. This occurs when toxins enter the tightly controlled inner ear environment inducing hair cell death, resulting in hearing loss. Recent studies have explored hydrogel-based bio-nanotechnologies and new drug delivery formulations to prevent drug-induced hearing loss, with much attention given to administration of antioxidant drugs. Bile acids have been recognized as promising excipients due to their biocompatibility and unique physiochemical properties. As yet bile acids have not been explored in improving drug delivery to the inner ear despite improving drug stability and delivery in other systems and demonstrating positive biological effects in their own right.
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29
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Zhou M, Johnston LJ, Wu C, Ma X. Gut microbiota and its metabolites: Bridge of dietary nutrients and obesity-related diseases. Crit Rev Food Sci Nutr 2021:1-18. [PMID: 34698581 DOI: 10.1080/10408398.2021.1986466] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
While the incidence of obesity keeps increasing in both adults and children worldwide, obesity and its complications remain major threatens to human health. Over the past decades, accumulating evidence has demonstrated the importance of microorganisms and their metabolites in the pathogenesis of obesity and related diseases. There also is a significant body of evidence validating the efficacy of microbial based therapies for managing various diseases. In this review, we collected the key information pertinent to obesity-related bacteria, fermentation substrates and major metabolites generated by studies involving humans and/or mice. We then briefly described the possible molecular mechanisms by which microorganisms cause or inhibit obesity with a focus on microbial metabolites. Lastly, we summarized the advantages and disadvantages of the utilization of probiotics, plant extracts, and exercise in controlling obesity. We speculated that new targets and combined approaches (e.g. diet combined with exercise) could lead to more precise prevention and/or alleviation of obesity in future clinical research implications.
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Affiliation(s)
- Min Zhou
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Lee J Johnston
- West Central Research & Outreach Center, University of Minnesota, Morris, Minnesota, USA
| | - Chaodong Wu
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX, USA
| | - Xi Ma
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
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30
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Piórkowska K, Żukowski K, Połtowicz K, Witarski W, Nowak J, Potocka P, Ropka-Molik K. Hypothalamus-pituitary axis transcriptomic modification dependent on growth rate in geese (Anser anser domesticus). Anim Genet 2021; 52:834-847. [PMID: 34595762 DOI: 10.1111/age.13140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2021] [Indexed: 11/28/2022]
Abstract
The hypothalamus-pituitary axis is involved in digest processing, stress response, energy storage and many other processes. In birds, this control differs from in mammals, such as regulation of appetite and satiety centre. The transcriptomics analyses of both brain structures can explain and identify the molecular processes related to body growth and development and nutritional status. Many reports describe chicken transcriptome in literature, but gene expression studies in the other poultry species are extremely rare. Therefore, the present research undertook the attempt to explain hypothalamus-pituitary processes in domestic geese-Polish White Kołuda®, main Polish line. After 16 weeks of fattening, significant differences in geese weight were observed. Therefore, transcriptome of pituitary and hypothalamus profiles could be compared between low and high growth rate geese groups. Due to the lack of domestic geese genome assembly in the public databases, we used three mapping approaches: de novo analysis, mapping to two other pink-footed and swan geese genomes. The functional examination showed that the most enriched biological process in the geese hypothalamus covered the immune response. Moreover, in the hypothalamus, proteins typical for the pituitary such as PRL and GH were differentially expressed (DE). Our study recommends one gene as a candidate for growth rate in geese-the FOS gene, which encodes Fos proto-oncogene-DE in both analysed tissues. The FOS gene is involved in regulating feeding behaviour, immune regulation, stimulating cellular proliferation and controlling growth hormone synthesis. Moreover, the present investigation indicates DE genes involved in gene expression regulation. The study delivers new information about the changes in the pituitary-hypothalamic axis in geese dependent on growth rate differences.
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Affiliation(s)
- Katarzyna Piórkowska
- Department of Animal Molecular Biology, National Research Institute of Animal Production, Balice, Poland
| | - Kacper Żukowski
- Department of Cattle Breeding, National Research Institute of Animal Production, Balice, Poland
| | - Katarzyna Połtowicz
- Department of Poultry Breeding, National Research Institute of Animal Production, Balice, Poland
| | - Wojciech Witarski
- Department of Animal Molecular Biology, National Research Institute of Animal Production, Balice, Poland
| | - Joanna Nowak
- Department of Poultry Breeding, National Research Institute of Animal Production, Balice, Poland
| | - Paulina Potocka
- National Research Institute of Animal Production, Experimental Station Kołuda Wielka, Janikowo, Poland
| | - Katarzyna Ropka-Molik
- Department of Animal Molecular Biology, National Research Institute of Animal Production, Balice, Poland
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31
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Zhang SY, Li RJW, Lim YM, Batchuluun B, Liu H, Waise TMZ, Lam TKT. FXR in the dorsal vagal complex is sufficient and necessary for upper small intestinal microbiome-mediated changes of TCDCA to alter insulin action in rats. Gut 2021; 70:1675-1683. [PMID: 33087489 DOI: 10.1136/gutjnl-2020-321757] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 10/01/2020] [Accepted: 10/02/2020] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Conjugated bile acids are metabolised by upper small intestinal microbiota, and serum levels of taurine-conjugated bile acids are elevated and correlated with insulin resistance in people with type 2 diabetes. However, whether changes in taurine-conjugated bile acids are necessary for small intestinal microbiome to alter insulin action remain unknown. DESIGN We evaluated circulating and specifically brain insulin action using the pancreatic-euglycaemic clamps in high-fat (HF) versus chow fed rats with or without upper small intestinal healthy microbiome transplant. Chemical and molecular gain/loss-of-function experiments targeting specific taurine-conjugated bile acid-induced changes of farnesoid X receptor (FXR) in the brain were performed in parallel. RESULTS We found that short-term HF feeding increased the levels of taurochenodeoxycholic acid (TCDCA, an FXR ligand) in the upper small intestine, ileum, plasma and dorsal vagal complex (DVC) of the brain. Transplantation of upper small intestinal healthy microbiome into the upper small intestine of HF rats not only reversed the rise of TCDCA in all reported tissues but also enhanced the ability of either circulating hyperinsulinaemia or DVC insulin action to lower glucose production. Further, DVC infusion of TCDCA or FXR agonist negated the enhancement of insulin action, while genetic knockdown or chemical inhibition of FXR in the DVC of HF rats reversed insulin resistance. CONCLUSION Our findings indicate that FXR in the DVC is sufficient and necessary for upper small intestinal microbiome-mediated changes of TCDCA to alter insulin action in rats, and highlight a previously unappreciated TCDCA-FXR axis linking gut microbiome and host insulin action.
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Affiliation(s)
- Song-Yang Zhang
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada
| | - Rosa J W Li
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada.,Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Yu-Mi Lim
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada.,Medical Research Institute, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | | | - Huiying Liu
- Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - T M Zaved Waise
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada
| | - Tony K T Lam
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada .,Physiology, University of Toronto, Toronto, Ontario, Canada.,Medicine, University of Toronto, Toronto, Ontario, Canada.,Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
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Mulak A. Bile Acids as Key Modulators of the Brain-Gut-Microbiota Axis in Alzheimer's Disease. J Alzheimers Dis 2021; 84:461-477. [PMID: 34569953 PMCID: PMC8673511 DOI: 10.3233/jad-210608] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2021] [Indexed: 12/11/2022]
Abstract
Recently, the concept of the brain-gut-microbiota (BGM) axis disturbances in the pathogenesis of Alzheimer's disease (AD) has been receiving growing attention. At the same time, accumulating data revealing complex interplay between bile acids (BAs), gut microbiota, and host metabolism have shed new light on a potential impact of BAs on the BGM axis. The crosstalk between BAs and gut microbiota is based on reciprocal interactions since microbiota determines BA metabolism, while BAs affect gut microbiota composition. Secondary BAs as microbe-derived neuroactive molecules may affect each of three main routes through which interactions within the BGM axis occur including neural, immune, and neuroendocrine pathways. BAs participate in the regulation of multiple gut-derived molecule release since their receptors are expressed on various cells. The presence of BAs and their receptors in the brain implies a direct effect of BAs on the regulation of neurological functions. Experimental and clinical data confirm that disturbances in BA signaling are present in the course of AD. Disturbed ratio of primary to secondary BAs as well as alterations in BA concertation in serum and brain samples have been reported. An age-related shift in the gut microbiota composition associated with its decreased diversity and stability observed in AD patients may significantly affect BA metabolism and signaling. Given recent evidence on BA neuroprotective and anti-inflammatory effects, new therapeutic targets have been explored including gut microbiota modulation by probiotics and dietary interventions, ursodeoxycholic acid supplementation, and use of BA receptor agonists.
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Affiliation(s)
- Agata Mulak
- Department of Gastroenterology and Hepatology, Wroclaw Medical University, Wroclaw, Poland
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Ní Dhonnabháín R, Xiao Q, O’Malley D. Aberrant Gut-To-Brain Signaling in Irritable Bowel Syndrome - The Role of Bile Acids. Front Endocrinol (Lausanne) 2021; 12:745190. [PMID: 34917022 PMCID: PMC8669818 DOI: 10.3389/fendo.2021.745190] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 11/04/2021] [Indexed: 12/12/2022] Open
Abstract
Functional bowel disorders such as irritable bowel syndrome (IBS) are common, multifactorial and have a major impact on the quality of life of individuals diagnosed with the condition. Heterogeneity in symptom manifestation, which includes changes in bowel habit and visceral pain sensitivity, are an indication of the complexity of the underlying pathophysiology. It is accepted that dysfunctional gut-brain communication, which incorporates efferent and afferent branches of the peripheral nervous system, circulating endocrine hormones and local paracrine and neurocrine factors, such as host and microbially-derived signaling molecules, underpins symptom manifestation. This review will focus on the potential role of hepatic bile acids in modulating gut-to-brain signaling in IBS patients. Bile acids are amphipathic molecules synthesized in the liver, which facilitate digestion and absorption of dietary lipids. They are also important bioactive signaling molecules however, binding to bile acid receptors which are expressed on many different cell types. Bile acids have potent anti-microbial actions and thereby shape intestinal bacterial profiles. In turn, bacteria with bile salt hydrolase activity initiate the critical first step in transforming primary bile acids into secondary bile acids. Individuals with IBS are reported to have altered microbial profiles and modified bile acid pools. We have assessed the evidence to support a role for bile acids in the pathophysiology underlying the manifestation of IBS symptoms.
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Affiliation(s)
- Róisín Ní Dhonnabháín
- Department of Physiology, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Qiao Xiao
- Department of Physiology, College of Medicine and Health, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Dervla O’Malley
- Department of Physiology, College of Medicine and Health, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- *Correspondence: Dervla O’Malley,
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Bile Acids: A Communication Channel in the Gut-Brain Axis. Neuromolecular Med 2020; 23:99-117. [PMID: 33085065 DOI: 10.1007/s12017-020-08625-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 10/08/2020] [Indexed: 02/08/2023]
Abstract
Bile acids are signalling hormones involved in the regulation of several metabolic pathways. The ability of bile acids to bind and signal through their receptors is modulated by the gut microbiome, since the microbiome contributes to the regulation and synthesis of bile acids as well to their physiochemical properties. From the gut, bacteria have been shown to send signals to the central nervous system via their metabolites, thus affecting the behaviour and brain function of the host organism. In the last years it has become increasingly evident that bile acids affect brain function, during normal physiological and pathological conditions. Although bile acids may be synthesized locally in the brain, the majority of brain bile acids are taken up from the systemic circulation. Since the composition of the brain bile acid pool may be regulated by the action of intestinal bacteria, it is possible that bile acids function as a communication bridge between the gut microbiome and the brain. However, little is known about the molecular mechanisms and the physiological roles of bile acids in the central nervous system. The possibility that bile acids may be a direct link between the intestinal microbiome and the brain is also an understudied subject. Here we review the influence of gut bacteria on the bile acid pool composition and properties, as well as striking evidence showing the role of bile acids as neuroactive molecules.
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Grant SM, DeMorrow S. Bile Acid Signaling in Neurodegenerative and Neurological Disorders. Int J Mol Sci 2020; 21:E5982. [PMID: 32825239 PMCID: PMC7503576 DOI: 10.3390/ijms21175982] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 12/13/2022] Open
Abstract
Bile acids are commonly known as digestive agents for lipids. The mechanisms of bile acids in the gastrointestinal track during normal physiological conditions as well as hepatic and cholestatic diseases have been well studied. Bile acids additionally serve as ligands for signaling molecules such as nuclear receptor Farnesoid X receptor and membrane-bound receptors, Takeda G-protein-coupled bile acid receptor and sphingosine-1-phosphate receptor 2. Recent studies have shown that bile acid signaling may also have a prevalent role in the central nervous system. Some bile acids, such as tauroursodeoxycholic acid and ursodeoxycholic acid, have shown neuroprotective potential in experimental animal models and clinical studies of many neurological conditions. Alterations in bile acid metabolism have been discovered as potential biomarkers for prognosis tools as well as the expression of various bile acid receptors in multiple neurological ailments. This review explores the findings of recent studies highlighting bile acid-mediated therapies and bile acid-mediated signaling and the roles they play in neurodegenerative and neurological diseases.
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Affiliation(s)
- Stephanie M. Grant
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, USA;
- Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Austin, TX 78712, USA
| | - Sharon DeMorrow
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, USA;
- Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Austin, TX 78712, USA
- Research Division, Central Texas Veterans Healthcare System, Austin, TX 78712, USA
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Keely S, Talley NJ. Duodenal bile acids as determinants of intestinal mucosal homeostasis and disease. Neurogastroenterol Motil 2020; 32:e13854. [PMID: 32323477 DOI: 10.1111/nmo.13854] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 12/14/2022]
Abstract
The duodenal epithelium plays a pivotal role in the uptake and transport of dietary nutrients while simultaneously acting as physical and biochemical barrier to protect against harmful bacteria and antigens. In the case of functional dyspepsia (FD), the duodenum is of particular interest, due to observed local immune involvement and the proximity to the stomach and exposure to acidopeptic secretions. Recent observations in FD pathophysiology, including those reported by Beeckmans et al in this issue of the journal, have identified a loss of barrier function in the duodenal epithelium, an altered duodenal microbiome and alterations in intestinal bile acid pools. Because FD symptoms coincide with food intake and, thus, secretion of bile acids, these findings may indicate loss or imbalance of bile-acid-microbiota-epithelial homeostasis as a process driving FD. Here, we review the evidence linking these observations to FD symptoms.
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Affiliation(s)
- Simon Keely
- Priority Research Centre for Digestive Health and Neurogastroenterology, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - Nicholas J Talley
- Priority Research Centre for Digestive Health and Neurogastroenterology, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
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Petrescu AD, Grant S, Williams E, Frampton G, Parks N, Blaney H, Davies M, John R, Reinhart EH, McMillin M, DeMorrow S. Coordinated Targeting of Galanin Receptors on Cholangiocytes and Hepatic Stellate Cells Ameliorates Liver Fibrosis in Multidrug Resistance Protein 2 Knockout Mice. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:586-601. [PMID: 31953035 PMCID: PMC7074378 DOI: 10.1016/j.ajpath.2019.10.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 09/20/2019] [Accepted: 10/22/2019] [Indexed: 01/12/2023]
Abstract
Galanin (Gal) is a peptide with a role in neuroendocrine regulation of the liver. In this study, we assessed the role of Gal and its receptors, Gal receptor 1 (GalR1) and Gal receptor 2 (GalR2), in cholangiocyte proliferation and liver fibrosis in multidrug resistance protein 2 knockout (Mdr2KO) mice as a model of chronic hepatic cholestasis. The distribution of Gal, GalR1, and GalR2 in specific liver cell types was assessed by laser-capture microdissection and confocal microscopy. Galanin immunoreactivity was detected in cholangiocytes, hepatic stellate cells (HSCs), and hepatocytes. Cholangiocytes expressed GalR1, whereas HSCs and hepatocytes expressed GalR2. Strategies were used to either stimulate or block GalR1 and GalR2 in FVB/N (wild-type) and Mdr2KO mice and measure biliary hyperplasia and hepatic fibrosis by quantitative PCR and immunostaining of specific markers. Galanin treatment increased cholangiocyte proliferation and fibrogenesis in both FVB/N and Mdr2KO mice. Suppression of GalR1, GalR2, or both receptors in Mdr2KO mice resulted in reduced bile duct mass and hepatic fibrosis. In vitro knockdown of GalR1 in cholangiocytes reduced α-smooth muscle actin expression in LX-2 cells treated with cholangiocyte-conditioned media. A GalR2 antagonist inhibited HSC activation when Gal was administered directly to LX-2 cells, but not via cholangiocyte-conditioned media. These data demonstrate that Gal contributes not only to cholangiocyte proliferation but also to liver fibrogenesis via the coordinate activation of GalR1 in cholangiocytes and GalR2 in HSCs.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B/genetics
- Animals
- Bile Ducts/metabolism
- Cell Proliferation
- Cholestasis/metabolism
- Cholestasis/pathology
- Disease Models, Animal
- Epithelial Cells/metabolism
- Female
- Galanin/genetics
- Galanin/metabolism
- Hepatic Stellate Cells/metabolism
- Hepatic Stellate Cells/pathology
- Liver/metabolism
- Liver/pathology
- Liver Cirrhosis/metabolism
- Liver Cirrhosis/pathology
- Mice
- Mice, Knockout
- Receptor, Galanin, Type 1/genetics
- Receptor, Galanin, Type 1/metabolism
- Receptor, Galanin, Type 2/genetics
- Receptor, Galanin, Type 2/metabolism
- ATP-Binding Cassette Sub-Family B Member 4
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Affiliation(s)
- Anca D Petrescu
- Research Division, Central Texas Veterans Health Care System, Temple, Texas; Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - Stephanie Grant
- Research Division, Central Texas Veterans Health Care System, Temple, Texas; Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - Elaina Williams
- Research Division, Central Texas Veterans Health Care System, Temple, Texas; Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - Gabriel Frampton
- Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Austin, Texas
| | | | - Hanna Blaney
- Department of Internal Medicine, Baylor Scott & White Health, Temple, Texas
| | - Marcus Davies
- Department of Internal Medicine, Baylor Scott & White Health, Temple, Texas
| | - Rebekah John
- Department of Internal Medicine, Baylor Scott & White Health, Temple, Texas
| | - Evan H Reinhart
- Department of Internal Medicine, Baylor Scott & White Health, Temple, Texas
| | - Matthew McMillin
- Research Division, Central Texas Veterans Health Care System, Temple, Texas; Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Austin, Texas
| | - Sharon DeMorrow
- Research Division, Central Texas Veterans Health Care System, Temple, Texas; Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas; Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Austin, Texas.
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Mao Y, Xu B, Guan W, Xu D, Li F, Ren R, Zhu X, Gao Y, Jiang L. The Adrenal Cortex, an Underestimated Site of SARS-CoV-2 Infection. Front Endocrinol (Lausanne) 2020; 11:593179. [PMID: 33488517 PMCID: PMC7820749 DOI: 10.3389/fendo.2020.593179] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 12/01/2020] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The majority of the critically ill patients may have critical illness-related corticosteroid insufficiency (CIRCI). The therapeutic effect of dexamethasone may be related to its ability to improve cortical function. Recent study showed that dexamethasone can reduce COVID-19 deaths by up to one third in critically ill patients. The aim of this article is to investigate whether SARS-CoV-2 can attack the adrenal cortex to aggravate the relative adrenal insufficiency. METHODS We summarized the clinical features of COVID-19 reported in currently available observational studies. ACE2 and TMPRSS2 expression was examined in human adrenal glands by immunohistochemical staining. We retrospectively analyzed serum cortisol levels in critically ill patients with or without COVID-19. RESULTS High percentage of critically ill patients with SARS-COV-2 infection in the study were treated with vasopressors. ACE2 receptor and TMPRSS2 serine protease were colocalized in adrenocortical cells in zona fasciculata and zona reticularis. We collected plasma cortisol concentrations in nine critically ill patients with COVID-19. The cortisol levels of critically ill patients with COVID-19 were lower than those in non-COVID-19 critically ill group. Six of the nine COVID-19 critically ill patients had random plasma cortisol concentrations below 10 µg/dl, which met the criteria for the diagnosis of CIRCI. CONCLUSION We demonstrate that ACE2 and TMPRSS2 are colocalized in adrenocortical cells, and that the cortisol levels are lower in critically ill patients with COVID-19 as compared to those of non-COVID-19 critically ill patients. Based on our findings, we recommend measuring plasma cortisol level to guide hormonal therapy.
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Affiliation(s)
- Yanfei Mao
- Department of Anesthesiology and Surgical Intensive Care Unit, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Bo Xu
- Department of Anesthesiology and Surgical Intensive Care Unit, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Wenbin Guan
- Department of Pathology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Dunfeng Xu
- Department of Anesthesiology and Surgical Intensive Care Unit, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Feng Li
- Department of Respiratory and Critical Care Medicine, Shanghai Public Health Clinical Center Affiliated to Fudan University, Shanghai, China
| | - Rongrong Ren
- Department of Anesthesiology and Surgical Intensive Care Unit, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xiaoyan Zhu
- Department of Physiology, Navy Medical University, Shanghai, China
- *Correspondence: Lai Jiang, ; Yuan Gao, ; Xiaoyan Zhu,
| | - Yuan Gao
- Department of Critical Care Medicine, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- *Correspondence: Lai Jiang, ; Yuan Gao, ; Xiaoyan Zhu,
| | - Lai Jiang
- Department of Anesthesiology and Surgical Intensive Care Unit, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- *Correspondence: Lai Jiang, ; Yuan Gao, ; Xiaoyan Zhu,
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Jacobs A, Derese I, Vander Perre S, Wouters PJ, Verbruggen S, Billen J, Vermeersch P, Garcia Guerra G, Joosten K, Vanhorebeek I, Van den Berghe G. Dynamics and prognostic value of the hypothalamus-pituitary-adrenal axis responses to pediatric critical illness and association with corticosteroid treatment: a prospective observational study. Intensive Care Med 2019; 46:70-81. [PMID: 31713058 PMCID: PMC6954148 DOI: 10.1007/s00134-019-05854-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 10/16/2019] [Indexed: 12/15/2022]
Abstract
PURPOSE Increased systemic cortisol availability during adult critical illness is determined by reduced binding-proteins and suppressed breakdown rather than elevated ACTH. Dynamics, drivers and prognostic value of hypercortisolism during pediatric critical illness remain scarcely investigated. METHODS This preplanned secondary analysis of the PEPaNIC-RCT (N = 1440), after excluding 420 children treated with corticosteroids before PICU-admission, documented (a) plasma ACTH, (free)cortisol and cortisol-metabolism at PICU-admission, day-3 and last PICU-day, their prognostic value, and impact of withholding early parenteral nutrition (PN), (b) the association between corticosteroid-treatment and these hormones, and (c) the association between corticosteroid-treatment and outcome. RESULTS ACTH was normal upon PICU-admission and low thereafter (p ≤ 0.0004). Total and free cortisol were only elevated upon PICU-admission (p ≤ 0.0003) and thereafter became normal despite low binding-proteins (p < 0.0001) and persistently suppressed cortisol-metabolism (p ≤ 0.03). Withholding early-PN did not affect this phenotype. On PICU-day-3, high free cortisol and low ACTH independently predicted worse outcome (p ≤ 0.003). Also, corticosteroid-treatment initiated in PICU, which further suppressed ACTH (p < 0.0001), was independently associated with poor outcomes (earlier live PICU-discharge: p < 0.0001, 90-day mortality: p = 0.02). CONCLUSION In critically ill children, systemic cortisol availability is elevated only transiently, much lower than in adults, and not driven by elevated ACTH. Further ACTH lowering by corticosteroid-treatment indicates active feedback inhibition at pituitary level. Beyond PICU-admission-day, low ACTH and high cortisol, and corticosteroid-treatment, predicted poor outcome. This suggests that exogenously increasing cortisol availability during acute critical illness in children may be inappropriate. Future studies on corticosteroid-treatment in critically ill children should plan safety analyses, as harm may be possible.
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Affiliation(s)
- An Jacobs
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Inge Derese
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Sarah Vander Perre
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Pieter J Wouters
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Sascha Verbruggen
- Intensive Care, Department of Pediatrics and Pediatric Surgery, Erasmus Medical Center, Sophia Children's Hospital, Doctor Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
| | - Jaak Billen
- Department of Laboratory Medicine, UZ Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Pieter Vermeersch
- Department of Laboratory Medicine, UZ Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Gonzalo Garcia Guerra
- Department of Pediatrics, Intensive Care Unit, Stollery Children's Hospital, University of Alberta, 8440, 112 St NW, Edmonton, AB, T6G 2B7, Canada
| | - Koen Joosten
- Intensive Care, Department of Pediatrics and Pediatric Surgery, Erasmus Medical Center, Sophia Children's Hospital, Doctor Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
| | - Ilse Vanhorebeek
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Greet Van den Berghe
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium.
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Liu L, Panzitt K, Racedo S, Wagner M, Platzer W, Zaufel A, Theiler‐Schwetz V, Obermayer‐Pietsch B, Müller H, Höfler G, Heinemann A, Zollner G, Fickert P. Bile acids increase steroidogenesis in cholemic mice and induce cortisol secretion in adrenocortical H295R cells via S1PR2, ERK and SF-1. Liver Int 2019; 39:2112-2123. [PMID: 30664326 PMCID: PMC6899711 DOI: 10.1111/liv.14052] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 01/10/2019] [Accepted: 01/13/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIMS Bile acids are now accepted as central signalling molecules for the regulation of glucose, amino acid and lipid metabolism. Adrenal gland cortex cells express the bile acid receptors farnesoid X receptor (FXR), the G protein-coupled bile acid receptor (TGR5) and the sphingosine-1-phosphate receptor 2 (S1PR2). We aimed to determine the effects of cholestasis and more specifically of bile acids on cortisol production. METHODS FXR and TGR5 knockout mice and controls were subjected to common bile duct ligation (CBDL) or chenodeoxycholic acid (CDCA) feeding to model cholestasis. Human adrenocortical H295R cells were challenged with bile acids for mechanistic studies. RESULTS We found that CBDL and CDCA feeding increased the levels of corticosterone, the rodent equivalent to human cortisol and mRNA and protein levels of steroidogenesis-related enzymes in adrenals independent of FXR and TGR5. Taurine-conjugated CDCA (TCDCA) significantly stimulated cortisol secretion, phosphorylation of extracellular signal-regulated kinase (ERK) and expression of steroidogenesis-related genes in human adrenocortical H295R cells. FXR and TGR5 agonists failed to induce cortisol secretion in H295R cells. S1PR2 inhibition significantly abolished TCDCA-induced cortisol secretion, lowered phosphorylation of ERK and abrogated enhanced transcription of steroidogenesis-related genes in H295R cells. Likewise, siRNA S1PR2 treatment reduced the phosphorylation of ERK and cortisol secretion. Steroidogenic factor-1 (SF-1) transactivation activity was increased upon TCDCA treatment suggesting that bile acid signalling is linked to SF-1. Treatment with SF-1 inverse agonist AC45594 also reduced TCDCA-induced steroidogenesis. CONCLUSIONS Our findings indicate that supraphysiological bile acid levels as observed in cholestasis stimulate steroidogenesis via an S1PR2-ERK-SF-1 signalling pathway.
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Affiliation(s)
- Lei Liu
- Research Unit for Experimental and Molecular HepatologyDivision of Gastroenterology and HepatologyDepartment of Internal MedicineMedical University of GrazGrazAustria
| | - Katrin Panzitt
- Research Unit for Translational Nuclear Receptor Research in Liver MetabolismDivision of Gastroenterology and HepatologyDepartment of Internal MedicineMedical University of GrazGrazAustria
| | - Silvia Racedo
- Research Unit for Experimental and Molecular HepatologyDivision of Gastroenterology and HepatologyDepartment of Internal MedicineMedical University of GrazGrazAustria
| | - Martin Wagner
- Research Unit for Translational Nuclear Receptor Research in Liver MetabolismDivision of Gastroenterology and HepatologyDepartment of Internal MedicineMedical University of GrazGrazAustria
| | - Wolfgang Platzer
- Institute of Experimental and Clinical PharmacologyMedical University of GrazGrazAustria
| | - Alex Zaufel
- Research Unit for Experimental and Molecular HepatologyDivision of Gastroenterology and HepatologyDepartment of Internal MedicineMedical University of GrazGrazAustria
| | | | | | - Helmut Müller
- Division of Transplant SurgeryMedical University of GrazGrazAustria
| | - Gerald Höfler
- Institute of PathologyMedical University of GrazGrazAustria
| | - Akos Heinemann
- Institute of Experimental and Clinical PharmacologyMedical University of GrazGrazAustria
| | - Gernot Zollner
- Research Unit for Experimental and Molecular HepatologyDivision of Gastroenterology and HepatologyDepartment of Internal MedicineMedical University of GrazGrazAustria
| | - Peter Fickert
- Research Unit for Experimental and Molecular HepatologyDivision of Gastroenterology and HepatologyDepartment of Internal MedicineMedical University of GrazGrazAustria
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Téblick A, Langouche L, Van den Berghe G. Anterior pituitary function in critical illness. Endocr Connect 2019; 8:R131-R143. [PMID: 31340197 PMCID: PMC6709544 DOI: 10.1530/ec-19-0318] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 07/24/2019] [Indexed: 12/13/2022]
Abstract
Critical illness is hallmarked by major changes in all hypothalamic-pituitary-peripheral hormonal axes. Extensive animal and human studies have identified a biphasic pattern in circulating pituitary and peripheral hormone levels throughout critical illness by analogy with the fasting state. In the acute phase of critical illness, following a deleterious event, rapid neuroendocrine changes try to direct the human body toward a catabolic state to ensure provision of elementary energy sources, whereas costly anabolic processes are postponed. Thanks to new technologies and improvements in critical care, the majority of patients survive the acute insult and recover within a week. However, an important part of patients admitted to the ICU fail to recover sufficiently, and a prolonged phase of critical illness sets in. This prolonged phase of critical illness is characterized by a uniform suppression of the hypothalamic-pituitary-peripheral hormonal axes. Whereas the alterations in hormonal levels during the first hours and days after the onset of critical illness are evolutionary selected and are likely beneficial for survival, endocrine changes in prolonged critically ill patients could be harmful and may hamper recovery. Most studies investigating the substitution of peripheral hormones or strategies to overcome resistance to anabolic stimuli failed to show benefit for morbidity and mortality. Research on treatment with selected and combined hypothalamic hormones has shown promising results. Well-controlled RCTs to corroborate these findings are needed.
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Affiliation(s)
- Arno Téblick
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Lies Langouche
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Greet Van den Berghe
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
- Correspondence should be addressed to G Van den Berghe:
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Téblick A, Peeters B, Langouche L, Van den Berghe G. Adrenal function and dysfunction in critically ill patients. Nat Rev Endocrinol 2019; 15:417-427. [PMID: 30850749 DOI: 10.1038/s41574-019-0185-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Critical illnesses are characterized by increased systemic cortisol availability, which is a vital part of the stress response. Relative adrenal failure (later termed critical-illness-related corticosteroid insufficiency (CIRCI)) is a condition in which the systemic availability of cortisol is assumed to be insufficiently high to face the stress of the illness and is most typically thought to occur in the acute phase of septic shock. Researchers suggested that CIRCI could be diagnosed by a suppressed incremental cortisol response to an injection of adrenocorticotropic hormone, irrespective of the baseline plasma cortisol. This concept triggered several randomized clinical trials on the impact of large stress doses of hydrocortisone to treat CIRCI, which gave conflicting results. Recent novel insights into the response of the hypothalamic-pituitary-adrenal axis to acute and prolonged critical illnesses challenge the concept of CIRCI, as currently defined, as well as the current practice guidelines for diagnosis and treatment. In this Review, these novel insights are integrated within a novel conceptual framework that can be used to re-appreciate adrenocortical function and dysfunction in the context of critical illness. This framework opens new avenues for further research and for preventive and/or therapeutic innovations.
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Affiliation(s)
- Arno Téblick
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven University, Leuven, Belgium
| | - Bram Peeters
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven University, Leuven, Belgium
| | - Lies Langouche
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven University, Leuven, Belgium
| | - Greet Van den Berghe
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven University, Leuven, Belgium.
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The Biosynthesis, Signaling, and Neurological Functions of Bile Acids. Biomolecules 2019; 9:biom9060232. [PMID: 31208099 PMCID: PMC6628048 DOI: 10.3390/biom9060232] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/13/2019] [Accepted: 06/14/2019] [Indexed: 12/13/2022] Open
Abstract
Bile acids (BA) are amphipathic steroid acids synthesized from cholesterol in the liver. They act as detergents to expedite the digestion and absorption of dietary lipids and lipophilic vitamins. BA are also considered to be signaling molecules, being ligands of nuclear and cell-surface receptors, including farnesoid X receptor and Takeda G-protein receptor 5. Moreover, BA also activate ion channels, including the bile acid-sensitive ion channel and epithelial Na+ channel. BA regulate glucose and lipid metabolism by activating these receptors in peripheral tissues, such as the liver and brown and white adipose tissue. Recently, 20 different BA have been identified in the central nervous system. Furthermore, BA affect the function of neurotransmitter receptors, such as the muscarinic acetylcholine receptor and γ-aminobutyric acid receptor. BA are also known to be protective against neurodegeneration. Here, we review recent findings regarding the biosynthesis, signaling, and neurological functions of BA.
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Nutritional Modulation of Immune and Central Nervous System Homeostasis: The Role of Diet in Development of Neuroinflammation and Neurological Disease. Nutrients 2019; 11:nu11051076. [PMID: 31096592 PMCID: PMC6566411 DOI: 10.3390/nu11051076] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 05/02/2019] [Accepted: 05/13/2019] [Indexed: 02/06/2023] Open
Abstract
The gut-microbiome-brain axis is now recognized as an essential part in the regulation of systemic metabolism and homeostasis. Accumulating evidence has demonstrated that dietary patterns can influence the development of metabolic alterations and inflammation through the effects of nutrients on a multitude of variables, including microbiome composition, release of microbial products, gastrointestinal signaling molecules, and neurotransmitters. These signaling molecules are, in turn, implicated in the regulation of the immune system, either promoting or inhibiting the production of pro-inflammatory cytokines and the expansion of specific leukocyte subpopulations, such as Th17 and Treg cells, which are relevant in the development of neuroinflammatory and neurodegenerative conditions. Metabolic diseases, like obesity and type 2 diabetes mellitus, are related to inadequate dietary patterns and promote variations in the aforementioned signaling pathways in patients with these conditions, which have been linked to alterations in neurological functions and mental health. Thus, maintenance of adequate dietary patterns should be an essential component of any strategy aiming to prevent neurological pathologies derived from systemic metabolic alterations. The present review summarizes current knowledge on the role of nutrition in the modulation of the immune system and its impact in the development of neuroinflammation and neurological disease.
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Abstract
Hepatic encephalopathy describes the array of neurological complications that arise due to liver insufficiency and/or portal-systemic shunt. The pathogenesis of hepatic encephalopathy shares a longstanding association with hyperammonemia and inflammation. Recently, aberrant bile acid signaling has been implicated in the development of key features of hepatic encephalopathy due to acute liver failure including neuronal dysfunction, neuroinflammation and blood-brain barrier permeability. This review summarizes the findings of recent studies demonstrating a role for bile acids in hepatic encephalopathy and speculates on the possible downstream consequences of bile acid signaling.
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Key Words
- ASBT, Apical Sodium-Dependent Bile Acid Transporter
- CCL2, Chemokine Ligand 2
- CCR2, Chemokine Receptor 2
- Cyp46A1, Cytochrome p450 46A1
- FXR, Farnesoid X Receptor
- GR, Glucocorticoid Receptor
- NTCP, Sodium Taurocholate Cotransporting Polypeptide
- PXR, Pregnane X Receptor
- S1P2R, Sphingosine 1 Phosphate Receptor 2
- TGR5, Takeda G-Protein Receptor 5
- Takeda G-protein coupled receptor 5 (TGR5)
- VDR, Vitamin D Receptor
- blood–brain barrier
- farnesoid X receptor
- neuroinflammation
- sphingosine-1-phosphate receptor 2
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Theiler-Schwetz V, Zaufel A, Schlager H, Obermayer-Pietsch B, Fickert P, Zollner G. Bile acids and glucocorticoid metabolism in health and disease. Biochim Biophys Acta Mol Basis Dis 2019; 1865:243-251. [DOI: 10.1016/j.bbadis.2018.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 07/18/2018] [Accepted: 08/01/2018] [Indexed: 12/12/2022]
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Dempsey J, Zhang A, Cui JY. Coordinate regulation of long non-coding RNAs and protein-coding genes in germ-free mice. BMC Genomics 2018; 19:834. [PMID: 30463508 PMCID: PMC6249886 DOI: 10.1186/s12864-018-5235-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 11/08/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Long non-coding RNAs (lncRNAs) are increasingly recognized as regulators of tissue-specific cellular functions and have been shown to regulate transcriptional and translational processes, acting as signals, decoys, guides, and scaffolds. It has been suggested that some lncRNAs act in cis to regulate the expression of neighboring protein-coding genes (PCGs) in a mechanism that fine-tunes gene expression. Gut microbiome is increasingly recognized as a regulator of development, inflammation, host metabolic processes, and xenobiotic metabolism. However, there is little known regarding whether the gut microbiome modulates lncRNA gene expression in various host metabolic organs. The goals of this study were to 1) characterize the tissue-specific expression of lncRNAs and 2) identify and annotate lncRNAs differentially regulated in the absence of gut microbiome. RESULTS Total RNA was isolated from various tissues (liver, duodenum, jejunum, ileum, colon, brown adipose tissue, white adipose tissue, and skeletal muscle) from adult male conventional and germ-free mice (n = 3 per group). RNA-Seq was conducted and reads were mapped to the mouse reference genome (mm10) using HISAT. Transcript abundance and differential expression was determined with Cufflinks using the reference databases NONCODE 2016 for lncRNAs and UCSC mm10 for PCGs. Although the constitutive expression of lncRNAs was ubiquitous within the enterohepatic (liver and intestine) and the peripheral metabolic tissues (fat and muscle) in conventional mice, differential expression of lncRNAs by lack of gut microbiota was highly tissue specific. Interestingly, the majority of gut microbiota-regulated lncRNAs were in jejunum. Most lncRNAs were co-regulated with neighboring PCGs. STRING analysis showed that differentially expressed PCGs in proximity to lncRNAs form tissue-specific networks, suggesting that lncRNAs may interact with gut microbiota/microbial metabolites to regulate tissue-specific functions. CONCLUSIONS This study is among the first to demonstrate that gut microbiota critically regulates the expression of lncRNAs not only locally in intestine but also remotely in other metabolic organs, suggesting that common transcriptional machinery may be shared to transcribe lncRNA-PCG pairs, and lncRNAs may interact with PCGs to regulate tissue-specific pathways.
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Affiliation(s)
- Joseph Dempsey
- Department of Environmental and Occupational Health Sciences, University of Washington, 4225 Roosevelt Way NE, Seattle, WA, 98105, USA
| | - Angela Zhang
- Department of Environmental and Occupational Health Sciences, University of Washington, 4225 Roosevelt Way NE, Seattle, WA, 98105, USA
| | - Julia Yue Cui
- Department of Environmental and Occupational Health Sciences, University of Washington, 4225 Roosevelt Way NE, Seattle, WA, 98105, USA.
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Al-Khaifi A, Straniero S, Voronova V, Chernikova D, Sokolov V, Kumar C, Angelin B, Rudling M. Asynchronous rhythms of circulating conjugated and unconjugated bile acids in the modulation of human metabolism. J Intern Med 2018; 284:546-559. [PMID: 29964306 DOI: 10.1111/joim.12811] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND OBJECTIVES Bile acids (BAs) traversing the enterohepatic circulation (EHC) influence important metabolic pathways. By determining individual serum BAs in relation to markers of metabolic activity, we explored how diurnal variations in their EHC relate to hepatic metabolism in normal humans. METHODS Serum BAs, fibroblast growth factor 19 (FGF19), lipoproteins, glucose/insulin and markers of cholesterol and BA syntheses were monitored for 32 h in 8 healthy males. Studies were conducted at basal state and during initiation of cholestyramine treatment, with and without atorvastatin pretreatment. Time series cross-correlation analysis, Bayesian structural model and Granger causality test were applied. RESULTS Bile acids synthesis dominated daytime, and cholesterol production at night. Conjugated BAs peaked after food intake, with subsequent FGF19 elevations. BA synthesis was reduced following conjugated BA and FGF19 peaks. Cholestyramine reduced conjugated BAs and FGF19, and increased BA and cholesterol production; the latter effects attenuated by atorvastatin. The relative importance of FGF19 vs. conjugated BAs in this feedback inhibition could not be discriminated. Unconjugated BAs displayed one major peak late at night/early morning that was unrelated to FGF19 and BA synthesis, and abolished by cholestyramine. The normal suppression of serum triglycerides, glucose and insulin observed at night was attenuated by cholestyramine. CONCLUSIONS Conjugated and unconjugated BAs have asynchronous rhythms of EHC in humans. Postprandial transintestinal flux of conjugated BAs increases circulating FGF19 levels and suppresses BA synthesis. Unconjugated BAs peak late at night, indicating a non-postprandial diurnal change in human gut microflora, the physiological implications of which warrants further study.
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Affiliation(s)
- A Al-Khaifi
- Metabolism Unit, Endocrinology, Metabolism and Diabetes, Department of Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.,Department of Medicine, Karolinska Institutet/AstraZeneca Integrated CardioMetabolic Center (KI/AZ ICMC), Novum, Stockholm, Sweden.,Department of Biochemistry, College of Medicine, Sultan Qaboos University, Muscat 123, Oman
| | - S Straniero
- Metabolism Unit, Endocrinology, Metabolism and Diabetes, Department of Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.,Department of Medicine, Karolinska Institutet/AstraZeneca Integrated CardioMetabolic Center (KI/AZ ICMC), Novum, Stockholm, Sweden
| | | | | | | | - C Kumar
- Department of Medicine, Karolinska Institutet/AstraZeneca Integrated CardioMetabolic Center (KI/AZ ICMC), Novum, Stockholm, Sweden.,Translational Sciences, Cardiovascular, Renal and Metabolism, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - B Angelin
- Metabolism Unit, Endocrinology, Metabolism and Diabetes, Department of Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.,Department of Medicine, Karolinska Institutet/AstraZeneca Integrated CardioMetabolic Center (KI/AZ ICMC), Novum, Stockholm, Sweden
| | - M Rudling
- Metabolism Unit, Endocrinology, Metabolism and Diabetes, Department of Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.,Department of Medicine, Karolinska Institutet/AstraZeneca Integrated CardioMetabolic Center (KI/AZ ICMC), Novum, Stockholm, Sweden
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Peeters B, Meersseman P, Vander Perre S, Wouters PJ, Debaveye Y, Langouche L, Van den Berghe G. ACTH and cortisol responses to CRH in acute, subacute, and prolonged critical illness: a randomized, double-blind, placebo-controlled, crossover cohort study. Intensive Care Med 2018; 44:2048-2058. [PMID: 30374692 PMCID: PMC6280831 DOI: 10.1007/s00134-018-5427-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 10/17/2018] [Indexed: 01/05/2023]
Abstract
Purpose Low plasma ACTH in critically ill patients may be explained by shock/inflammation-induced hypothalamus-pituitary damage or by feedback inhibition exerted by elevated plasma free cortisol. One can expect augmented/prolonged ACTH-responses to CRH injection with hypothalamic damage, immediately suppressed responses with pituitary damage, and delayed decreased responses in prolonged critical illness with feedback inhibition. Methods This randomized, double-blind, placebo-controlled crossover cohort study, compared ACTH responses to 100 µg IV CRH and placebo in 3 cohorts of 40 matched patients in the acute (ICU-day 3–6), subacute (ICU-day 7–16) or prolonged phase (ICU-day 17–28) of critical illness, with 20 demographically matched healthy subjects. CRH or placebo was injected in random order on two consecutive days. Blood was sampled repeatedly over 135 min and AUC responses to placebo were subtracted from those to CRH. Results Patients had normal mean ± SEM plasma ACTH concentrations (25.5 ± 1.6 versus 24.8 ± 3.6 pg/ml in healthy subjects, P = 0.54) but elevated free cortisol concentrations (3.11 ± 0.27 versus 0.58 ± 0.05 µg/dl in healthy subjects, P < 0.0001). The order of the CRH/placebo injections did not affect the ACTH responses, hence results were pooled. Patients in the acute phase of illness had normal mean ± SEM ACTH responses (5149 ± 848 pg/mL min versus 4120 ± 688 pg/mL min in healthy subjects; P = 0.77), whereas those in the subacute (2333 ± 387 pg/mL min, P = 0.01) and prolonged phases (2441 ± 685 pg/mL min, P = 0.001) were low, irrespective of sepsis/septic shock or risk of death. Conclusions Suppressed ACTH responses to CRH in the more prolonged phases, but not acute phase, of critical illness are compatible with feedback inhibition exerted by elevated free cortisol, rather than by cellular damage to hypothalamus and/or pituitary. Electronic supplementary material The online version of this article (10.1007/s00134-018-5427-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bram Peeters
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Philippe Meersseman
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium.,Medical Intensive Care Unit, Department of General Internal Medicine, UZ Leuven, Leuven, Belgium
| | - Sarah Vander Perre
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Pieter J Wouters
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Yves Debaveye
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Lies Langouche
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Greet Van den Berghe
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium.
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50
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McMillin M, Grant S, Frampton G, Petrescu AD, Kain J, Williams E, Haines R, Canady L, DeMorrow S. FXR-Mediated Cortical Cholesterol Accumulation Contributes to the Pathogenesis of Type A Hepatic Encephalopathy. Cell Mol Gastroenterol Hepatol 2018; 6:47-63. [PMID: 29928671 PMCID: PMC6008252 DOI: 10.1016/j.jcmgh.2018.02.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 02/26/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Hepatic encephalopathy is a serious neurologic complication of acute and chronic liver diseases. We previously showed that aberrant bile acid signaling contributes to the development of hepatic encephalopathy via farnesoid X receptor (FXR)-mediated mechanisms in neurons. In the brain, a novel alternative bile acid synthesis pathway, catalyzed by cytochrome p450 46A1 (Cyp46A1), is the primary mechanism by which the brain regulates cholesterol homeostasis. The aim of this study was to determine if FXR activation in the brain altered cholesterol homeostasis during hepatic encephalopathy. METHODS Cyp7A1-/- mice or C57Bl/6 mice pretreated with central infusion of FXR vivo morpholino, 2-hydroxypropyl-β-cyclodextrin, or fed a cholestyramine-supplemented diet were injected with azoxymethane (AOM). Cognitive and neuromuscular impairment as well as liver damage and expression of Cyp46A1 were assessed using standard techniques. The subsequent cholesterol content in the frontal cortex was measured using commercially available kits and by Filipin III and Nile Red staining. RESULTS There was an increase in membrane-bound and intracellular cholesterol in the cortex of mice treated with AOM that was associated with decreased Cyp46A1 expression. Strategies to inhibit FXR signaling prevented the down-regulation of Cyp46A1 and the accumulation of cholesterol. Treatment of mice with 2-hydroxypropyl-β-cyclodextrin attenuated the AOM-induced cholesterol accumulation in the brain and the cognitive and neuromuscular deficits without altering the underlying liver pathology. CONCLUSIONS During hepatic encephalopathy, FXR signaling increases brain cholesterol and contributes to neurologic decline. Targeting cholesterol accumulation in the brain may be a possible therapeutic target for the management of hepatic encephalopathy.
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Key Words
- 2-HβC, 2-hypdroxypropyl-β-cyclodextrin
- AOM, azoxymethane
- Acute Liver Failure
- Azoxymethane
- CYP46A1, cytochrome p450 46A1
- CYP7A1, cytochrome p450 7A1
- Cytochrome p450 46A1
- FXR, farnesoid X receptor
- Farnesoid X Receptor
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- PBS, phosphate-buffered saline
- PFA, paraformaldehyde
- RT-PCR, reverse-transcription polymerase chain reaction
- WT, wild-type
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Affiliation(s)
- Matthew McMillin
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Stephanie Grant
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Gabriel Frampton
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Anca D. Petrescu
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Jessica Kain
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Elaina Williams
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Rebecca Haines
- Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Lauren Canady
- Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Sharon DeMorrow
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas,Correspondence Address correspondence to: Sharon DeMorrow, PhD, Department of Medical Physiology, Texas A&M Health Science Center, Central Texas Veterans Health Care System, Building 205, 1901 South 1st Street, Temple, Texas 76504. fax: (254) 743-0378.
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