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Schneider E, O'Riordan KJ, Clarke G, Cryan JF. Feeding gut microbes to nourish the brain: unravelling the diet-microbiota-gut-brain axis. Nat Metab 2024; 6:1454-1478. [PMID: 39174768 DOI: 10.1038/s42255-024-01108-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 07/15/2024] [Indexed: 08/24/2024]
Abstract
The prevalence of brain disorders, including stress-related neuropsychiatric disorders and conditions with cognitive dysfunction, is rising. Poor dietary habits contribute substantially to this accelerating trend. Conversely, healthy dietary intake supports mood and cognitive performance. Recently, the communication between the microorganisms within the gastrointestinal tract and the brain along the gut-brain axis has gained prominence as a potential tractable target to modulate brain health. The composition and function of the gut microbiota is robustly influenced by dietary factors to alter gut-brain signalling. To reflect this interconnection between diet, gut microbiota and brain functioning, we propose that a diet-microbiota-gut-brain axis exists that underpins health and well-being. In this Review, we provide a comprehensive overview of the interplay between diet and gut microbiota composition and function and the implications for cognition and emotional functioning. Important diet-induced effects on the gut microbiota for the development, prevention and maintenance of neuropsychiatric disorders are described. The diet-microbiota-gut-brain axis represents an uncharted frontier for brain health diagnostics and therapeutics across the lifespan.
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Affiliation(s)
| | | | - Gerard Clarke
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland
| | - John F Cryan
- APC Microbiome Ireland, University College Cork, Cork, Ireland.
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
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Peng TR, Lin HH, Lee MC, Chen SM. Statins as an adjuvant therapy for patients with schizophrenia: An up-to-date systematic review and meta-analysis. Gen Hosp Psychiatry 2024; 89:75-83. [PMID: 38824832 DOI: 10.1016/j.genhosppsych.2024.05.001] [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: 11/20/2023] [Revised: 04/30/2024] [Accepted: 05/01/2024] [Indexed: 06/04/2024]
Abstract
BACKGROUND Evidence suggests that inflammatory processes play a role in the pathophysiology of schizophrenia. Statins exert anti-inflammatory and antioxidant effects and may be effective in improving the symptoms of schizophrenia. This study explored whether statins, as an adjunctive therapy, can alleviate the symptoms of schizophrenia. METHODS PubMed, EMBASE, and the Cochrane Library were searched for articles published up to March 2023. The risk-of-bias tool for randomized trials was used to assess study quality. Two researchers independently assessed the risks of bias and extracted data. Pooled data on Positive and Negative Syndrome Scale (PANSS) scores were analyzed. A random-effects model was employed to calculate pooled effect sizes. Statistical heterogeneity across studies was assessed using the I2 statistic. All analyses were performed using RevMan5 and Comprehensive Meta-Analysis software. RESULTS Nine trials enrolling 533 patients in total were included. Add-on statin therapy was found to be associated with a significantly better total PANSS score [standardized mean difference (SMD) = -0.42, 95% confidence interval (CI) -0.75 to -0.09, I2 = 72%; P = 0.01] and PANSS negative subscale score (SMD = -0.26, 95% CI -0.45 to -0.07, I2 = 0%; P = 0.009) in comparison with placebo. However, add-on statin therapy did not appear to improve scores for the PANSS positive and general subscales at the study-defined endpoint (6-24 weeks). CONCLUSIONS Our meta-analysis indicates that adjunctive statin therapy may confer benefits in ameliorating PANSS negative and total scores. It needs more solid data to confirm the results are related to clinical improvement and functioning.
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Affiliation(s)
- Tzu-Rong Peng
- Department of Pharmacy, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City, Taiwan; School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Hung-Hong Lin
- Department of Pharmacy, Chia-Nan University of Pharmacy and Science, Tainan, Taiwan
| | - Ming-Chia Lee
- School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan; Department of Pharmacy, New Taipei City Hospital, New Taipei City, Taiwan; Department of Nursing, Cardinal Tien College of Healthcare and Management, Taipei, Taiwan.
| | - Shih-Ming Chen
- School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan.
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Zaki JK, Lago SG, Spadaro B, Rustogi N, Gangadin SS, Benacek J, Drexhage HA, de Witte LD, Kahn RS, Sommer IEC, Bahn S, Tomasik J. Exploring peripheral biomarkers of response to simvastatin supplementation in schizophrenia. Schizophr Res 2024; 266:66-74. [PMID: 38377869 DOI: 10.1016/j.schres.2024.02.011] [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: 01/25/2023] [Revised: 02/02/2024] [Accepted: 02/11/2024] [Indexed: 02/22/2024]
Abstract
Schizophrenia is one of the most debilitating mental disorders, and its diagnosis and treatment present significant challenges. Several clinical trials have previously evaluated the effectiveness of simvastatin, a lipid-lowering medication, as a novel add-on treatment for schizophrenia. However, treatment effects varied highly between patients and over time. In the present study, we aimed to identify biomarkers of response to simvastatin in recent-onset schizophrenia patients. To this end, we profiled relevant immune and metabolic markers in patient blood samples collected in a previous clinical trial (ClinicalTrials.gov: NCT01999309) before simvastatin add-on treatment was initiated. Analysed sample types included serum, plasma, resting-state peripheral blood mononuclear cells (PBMCs), as well as PBMC samples treated ex vivo with immune stimulants and simvastatin. Associations between the blood readouts and clinical endpoints were evaluated using multivariable linear regression. This revealed that changes in insulin receptor (IR) levels induced in B-cells by ex vivo simvastatin treatment inversely correlated with in vivo effects on cognition at the primary endpoint of 12 months, as measured using the Brief Assessment of Cognition in Schizophrenia scale total score (standardised β ± SE = -0.75 ± 0.16, P = 2.2 × 10-4, Q = 0.029; n = 21 patients). This correlation was not observed in the placebo group (β ± SE = 0.62 ± 0.39, P = 0.17, Q = 0.49; n = 14 patients). The candidate biomarker explained 53.4 % of the variation in cognitive outcomes after simvastatin supplementation. Despite the small sample size, these findings suggest a possible interaction between the insulin signalling pathway and cognitive effects during simvastatin therapy. They also point to opportunities for personalized schizophrenia treatment through patient stratification.
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Affiliation(s)
- Jihan K Zaki
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Santiago G Lago
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Benedetta Spadaro
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Nitin Rustogi
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Shiral S Gangadin
- Department of Biomedical Sciences of Cells & Systems, University Medical Center Groningen (UMCG), University of Groningen, Groningen, the Netherlands
| | - Jiri Benacek
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Hemmo A Drexhage
- Department of Immunology, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Lot D de Witte
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - René S Kahn
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Psychiatry, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Iris E C Sommer
- Department of Biomedical Sciences of Cells & Systems, University Medical Center Groningen (UMCG), University of Groningen, Groningen, the Netherlands; Department of Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Sabine Bahn
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK.
| | - Jakub Tomasik
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK.
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Messina A, Concerto C, Rodolico A, Petralia A, Caraci F, Signorelli MS. Is It Time for a Paradigm Shift in the Treatment of Schizophrenia? The Use of Inflammation-Reducing and Neuroprotective Drugs-A Review. Brain Sci 2023; 13:957. [PMID: 37371435 DOI: 10.3390/brainsci13060957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 06/03/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
Comprehending the pathogenesis of schizophrenia represents a challenge for global mental health. To date, although it is evident that alterations in dopaminergic, serotonergic, and glutamatergic neurotransmission underlie the clinical expressiveness of the disease, neuronal disconnections represent only an epiphenomenon. In recent years, several clinical studies have converged on the hypothesis of microglia hyperactivation and a consequent neuroinflammatory state as a pathogenic substrate of schizophrenia. Prenatal, perinatal, and postnatal factors can cause microglia to switch from M2 anti-inflammatory to M1 pro-inflammatory states. A continuous mild neuroinflammatory state progressively leads to neuronal loss, a reduction in dendritic spines, and myelin degeneration. The augmentation of drugs that reduce neuroinflammation to antipsychotics could be an effective therapeutic modality in managing schizophrenia. This review will consider studies in which drugs with anti-inflammatory and neuroprotective properties have been used in addition to antipsychotic treatment in patients with schizophrenia.
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Affiliation(s)
- Antonino Messina
- Department of Clinical and Experimental Medicine, Institute of Psychiatry, University of Catania, 95123 Catania, Italy
| | - Carmen Concerto
- Department of Clinical and Experimental Medicine, Institute of Psychiatry, University of Catania, 95123 Catania, Italy
| | - Alessandro Rodolico
- Department of Clinical and Experimental Medicine, Institute of Psychiatry, University of Catania, 95123 Catania, Italy
| | - Antonino Petralia
- Department of Clinical and Experimental Medicine, Institute of Psychiatry, University of Catania, 95123 Catania, Italy
| | - Filippo Caraci
- Department of Drug and Health Sciences, University of Catania, 95123 Catania, Italy
- Unit of Translational Neuropharmacology and Translational Neurosciences, Oasi Research Institute-IRCCS, 94018 Troina, Italy
| | - Maria Salvina Signorelli
- Department of Clinical and Experimental Medicine, Institute of Psychiatry, University of Catania, 95123 Catania, Italy
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Is it possible to stage schizophrenia? A systematic review. Transl Psychiatry 2022; 12:197. [PMID: 35545617 PMCID: PMC9095725 DOI: 10.1038/s41398-022-01889-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 02/07/2022] [Accepted: 03/09/2022] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION A staging model is a clinical tool used to define the development of a disease over time. In schizophrenia, authors have proposed different theoretical staging models of increasing complexity. Therefore, the aims of our study were to provide an updated and critical view of the proposed clinical staging models for schizophrenia and to review the empirical data that support them. METHODS Systematic literature review following PRISMA guidelines. From the PubMed database and backward reference search, a total of 141 records were retrieved, but only 20 were selected according to the inclusion criteria: (a) available in English; (b) participants with schizophrenia ≥ 18 years; and (c) theoretical and empirical research studies intended to develop, validate, and/or improve staging models of schizophrenia. RESULTS Different clinical staging models for schizophrenia were identified, information about the proposed stages was tabulated and presented in the Results section (Tables 1, 2). Most of which include neuroimaging, functioning, and psychopathology, but only two models add objective biomarkers and none include patient point of view. However, few models have been psychometrically tested or used small samples and thus have been validated only partially. In addition, five studies proposed therapeutic interventions according to the stage of the disorder from a theoretical point of view. DISCUSSION In conclusion, it is possible to stage schizophrenia, but the models developed have several limitations. Empirical validation and inclusion of more specific biomarkers and measures of other life areas affected by schizophrenia could help in the development of more valid models.
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Higher Dietary Inflammation in Patients with Schizophrenia: A Case-Control Study in Korea. Nutrients 2021; 13:nu13062033. [PMID: 34199231 PMCID: PMC8231973 DOI: 10.3390/nu13062033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 11/16/2022] Open
Abstract
Inflammation is a risk factor for the onset and progression of schizophrenia, and dietary factors are related to chronic inflammation. We investigated whether the dietary inflammatory index (DII) is associated with schizophrenia in the Korean population. Of the 256 subjects who responded to the questionnaire, 184 subjects (117 controls; 67 individuals with schizophrenia) were included in this case-control study. A semi-quantitative food frequency questionnaire was used to evaluate the dietary intakes of the study participants. The energy-adjusted DII (E-DII) was used to assess the inflammatory potential of the participants' diets. Dietary intakes of vitamin C, niacin, and folate were significantly reduced in the patients with schizophrenia. The patients with schizophrenia had higher E-DII scores than the controls (p = 0.011). E-DII was positively associated with schizophrenia (odds ratio = 1.254, p = 0.010). The additional analysis confirmed that E-DII was significantly associated with schizophrenia, especially in the third tertile group of E-DII scores (odds ratio = 2.731, p = 0.016). Our findings suggest that patients with schizophrenia have more pro-inflammatory diets.
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Cha HY, Yang SJ. Anti-Inflammatory Diets and Schizophrenia. Clin Nutr Res 2020; 9:241-257. [PMID: 33204665 PMCID: PMC7644368 DOI: 10.7762/cnr.2020.9.4.241] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 10/02/2020] [Accepted: 10/07/2020] [Indexed: 12/13/2022] Open
Abstract
Schizophrenia is a mental illness characterized by symptoms such as hallucinations, delusions, disorganized speech, disorganized or catatonic behavior, and negative symptoms (emotional flatness, apathy, and lack of speech). It causes social and economic burdens to patients and their family. Although etiology of schizophrenia is still uncertain, dopamine dysregulation is traditionally considered as a main etiological factor of schizophrenia, which has been utilized to develop drugs for treating schizophrenia. Recently, inflammation has presented being a risk factor for schizophrenia in that neuroinflammation contributes to the pathophysiology of schizophrenia and the exacerbation of symptom severity. Various factors including diet can regulate inflammatory state. Specific foods or dietary patterns have anti- or pro-inflammatory potentials. Increased levels of pro-inflammatory cytokines and microglia activation have been reported in schizophrenia populations and were related to the pathogenesis of schizophrenia. Omega-3 fatty acids were often recommended to schizophrenia patients because of their anti-inflammatory activities. In this review, we investigate the inflammation-related pathogenesis of schizophrenia and summarize potential nutritional approaches to inhibit the manifestation of symptoms and to alleviate symptom severity using anti-inflammatory nutrients or functional components.
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Affiliation(s)
- Hee Yun Cha
- Department of Food and Nutrition, Seoul Women's University, Seoul 01797, Korea
| | - Soo Jin Yang
- Department of Food and Nutrition, Seoul Women's University, Seoul 01797, Korea
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Arabska J, Strzelecki D, Kozłowska E, Brzezińska-Błaszczyk E, Wysokiński A. The association between serum levels of TNF-α and IL-6 in schizophrenic patients and their metabolic status - A case control study. J Neuroimmunol 2020; 347:577344. [PMID: 32777628 DOI: 10.1016/j.jneuroim.2020.577344] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 07/18/2020] [Accepted: 07/19/2020] [Indexed: 01/06/2023]
Abstract
INTRODUCTION AND OBJECTIVES According to immunological theory of schizophrenia, dysfunctions of the immune system are linked with the pathology of schizophrenia. Among cytokines, tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) seem to be correlated with psychopathology of schizophrenia. Both IL-6 and TNF-α are produced in the fat tissue by adipocytes. Thus, cytokine levels in obese patients are increased compared with healthy subjects. These metabolic underlying mechanisms may be an important confounding factor in the studies on cytokines levels in schizophrenia. The aim of this study was to evaluate how metabolic alterations affect peripheral IL-6 and TNF-α levels in schizophrenia patients. MATERIALS AND METHODS This was a case-control study, 30 schizophrenia patients were recruited in the study group and 30 healthy subjects were matched by sex and age. Serum levels of TNF-α and Il-6 were measured using ELISA test, together with detailed anthropometric, laboratory and body composition parameters (determined using bioelectric impedance analysis). RESULTS AND CONCLUSIONS Serum TNF-α concentration in the schizophrenia group was 6.05 ± 1.61 ng/mL and 5.94 ± 1.26 ng/mL in the control group. The difference between these two groups was not significant (p = .79). Serum IL-6 concentration in the schizophrenia group was 1.54 ± 1.46 ng/mL and in the control group 1.39 ± 1.39 ng/mL. Again, the difference was not significant (p = .51). We have analysed the relationship between anthropometric and metabolic variables and serum IL-6 and TNF-α concentrations. In conclusion, TNF-α was more sensitive to metabolic alterations compared with IL-6. This observation may be beneficial for further research on immune system in schizophrenia, indicating that studies of IL-6 and TNF-α should be controlled at least for major metabolic parameters (BMI, WHR).
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Affiliation(s)
- Jaśmina Arabska
- Department of Old Age Psychiatry and Psychotic Disorders, Medical University of Lodz, Lodz, Poland
| | - Dominik Strzelecki
- Department of Affective and Psychotic Disorders, Medical University of Lodz, Lodz, Poland
| | - Elżbieta Kozłowska
- Department of Experimental Immunology, Medical University of Lodz, Poland
| | | | - Adam Wysokiński
- Department of Old Age Psychiatry and Psychotic Disorders, Medical University of Lodz, Lodz, Poland.
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Qi J, Chen LY, Shen XJ, Ju SQ. Analytical Value of Cell-Free DNA Based on Alu in Psychiatric Disorders. Front Psychiatry 2019; 10:992. [PMID: 32038328 PMCID: PMC6985436 DOI: 10.3389/fpsyt.2019.00992] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 12/13/2019] [Indexed: 11/17/2022] Open
Abstract
Psychiatric disorders impose a huge burden on individuals, families, and society. The Alu repeat sequence is a member of the short interspersed nuclear element (SINE) family of mammalian genomes, however, its expression pattern and role in psychiatric disorders is unclear. The current paper aimed at determining the concentrations of Alu in patients with schizophrenia (SZ), major depressive disorder (MDD), and alcohol-induced psychotic disorder (AIPD), and to further define the role and value of Alu as a potential biomarker in psychiatric disorders. In this work, we found that the concentration of Alu was considerably incremented in patients with SZ, and a significant difference existed between patients diagnosed with SZ and MDD or AIPD. ROC analysis also indicated that Alu was effective in the complementary diagnosis of SZ, and differentially diagnosed between SZ patients and patients with MDD or AIPD. In addition, we found a positive relationship between the Alu concentrations and interleukin-1β (IL-1β) in patients with SZ, MDD, and AIPD, and between the concentrations of Alu and interleukin-18 (IL-18) in patients with SZ. Overall, the present work indicates that Alu might be an innovative biomarker for diagnosing psychiatric disorders, and provides the basis for hypotheses about the pathophysiology of psychiatric disorders.
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Affiliation(s)
- Jing Qi
- Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong, China
| | - Ling-Yun Chen
- Center of Laboratory Medicine, Nantong Mental Health Center, Nantong, China
| | - Xian-Juan Shen
- Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong, China
| | - Shao-Qing Ju
- Center of Laboratory Medicine, Affiliated Hospital of Nantong University, Nantong, China
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