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Ramazani Z, Nakhaee S, Sharafi K, Rezaei Z, Mansouri B. Autism spectrum disorder: Cadmium and mercury concentrations in different biological samples, a systematic literature review and meta-analysis of human studies. Heliyon 2024; 10:e27789. [PMID: 38496888 PMCID: PMC10944282 DOI: 10.1016/j.heliyon.2024.e27789] [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: 06/13/2023] [Revised: 02/28/2024] [Accepted: 03/06/2024] [Indexed: 03/19/2024] Open
Abstract
The present study was conducted to investigate the differences in cadmium (Cd) and mercury (Hg) concentrations between children with autism spectrum disorder (ASD) and controls. In this systematic review and meta-analysis study, three thousand one hundred forty-five studies were collected from scientific databases including Web of Science, Scopus, PubMed, and Google Scholar from January 2000 to October 2022 and were investigated for eligibility. As a result, 37 studies published in the period from 2003 to 2022 met our inclusion criteria and were considered in the meta-analysis. The heterogeneity assumption was evaluated using the Chi-squared-based Q-test and I-squared (I2) statistics. The pooled estimates were shown in the forest plots with Hedges' g (95% confidence interval) values. The random effects model demonstrated that there is no significant difference in the blood (Hedges' g: 0.14, 95% CI: 0.45, 0.72, p > 0.05), hair (Hedges' g: 0.12, 95% CI: 0.26, 0.50, p > 0.05), and urinary (Hedges' g: 0.05, 95% CI: 0.86, 0.76, p > 0.05) Cd levels of the case group versus control subjects. Moreover, the pooled findings of studies showed no significant difference in the blood (Hedges' g: 1.69, 95% CI: 0.09, 3.48, p > 0.05), hair (Hedges' g: 3.42, 95% CI: 1.96, 8.80, p > 0.05), and urinary (Hedges' g: 0.49, 95% CI: 1.29 - 0.30, p > 0.05) Hg concentrations. The results demonstrated no significant differences in Hg and Cd concentrations in different biological samples of children with ASD compared to control subjects.
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Affiliation(s)
- Zana Ramazani
- Substance Abuse Prevention Research Center, Research Institute for Health, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Samaneh Nakhaee
- Medical Toxicology and Drug Abuse Research Center (MTDRC), Birjand University of Medical Sciences, Birjand, Iran
| | - Kiomars Sharafi
- Research Center for Environmental Determinants of Health (RCEDH), Research Institute for Health, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Zaynab Rezaei
- Substance Abuse Prevention Research Center, Research Institute for Health, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Borhan Mansouri
- Substance Abuse Prevention Research Center, Research Institute for Health, Kermanshah University of Medical Sciences, Kermanshah, Iran
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Stojsavljević A, Lakićević N, Pavlović S. Mercury and Autism Spectrum Disorder: Exploring the Link through Comprehensive Review and Meta-Analysis. Biomedicines 2023; 11:3344. [PMID: 38137565 PMCID: PMC10741416 DOI: 10.3390/biomedicines11123344] [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: 10/29/2023] [Revised: 12/02/2023] [Accepted: 12/13/2023] [Indexed: 12/24/2023] Open
Abstract
Mercury (Hg) is a non-essential trace metal with unique neurochemical properties and harmful effects on the central nervous system. In this study, we present a comprehensive review and meta-analysis of peer-reviewed research encompassing five crucial clinical matrices: hair, whole blood, plasma, red blood cells (RBCs), and urine. We assess the disparities in Hg levels between gender- and age-matched neurotypical children (controls) and children diagnosed with autism spectrum disorder (ASD) (cases). After applying rigorous selection criteria, we incorporated a total of 60 case-control studies into our meta-analysis. These studies comprised 25 investigations of Hg levels in hair (controls/cases: 1134/1361), 15 in whole blood (controls/cases: 1019/1345), 6 in plasma (controls/cases: 224/263), 5 in RBCs (controls/cases: 215/293), and 9 in urine (controls/cases: 399/623). This meta-analysis did not include the data of ASD children who received chelation therapy. Our meta-analysis revealed no statistically significant differences in Hg levels in hair and urine between ASD cases and controls. In whole blood, plasma, and RBCs, Hg levels were significantly higher in ASD cases compared to their neurotypical counterparts. This indicates that ASD children could exhibit reduced detoxification capacity for Hg and impaired mechanisms for Hg excretion from their bodies. This underscores the detrimental role of Hg in ASD and underscores the critical importance of monitoring Hg levels in ASD children, particularly in early childhood. These findings emphasize the pressing need for global initiatives aimed at minimizing Hg exposure, thus highlighting the critical intersection of human-environment interaction and neurodevelopment health.
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Affiliation(s)
- Aleksandar Stojsavljević
- Innovative Centre, Faculty of Chemistry, University of Belgrade, Studentski Trg 12–16, 11000 Belgrade, Serbia
| | - Novak Lakićević
- Clinical Centre of Montenegro, Clinic for Neurosurgery, Ljubljanska bb, 81000 Podgorica, Montenegro;
| | - Slađan Pavlović
- Institute for Biological Research “Siniša Stanković”—National Institute of the Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia;
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Lin HH, Jung CR, Lin CY, Chang YC, Hsieh CY, Hsu PC, Chuang BR, Hwang BF. Prenatal and postnatal exposure to heavy metals in PM 2.5 and autism spectrum disorder. ENVIRONMENTAL RESEARCH 2023; 237:116874. [PMID: 37595830 DOI: 10.1016/j.envres.2023.116874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 07/20/2023] [Accepted: 08/10/2023] [Indexed: 08/20/2023]
Abstract
Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders, and its incidence is increasing over time. Although several environmental factors have been suspected to be risk factors for ASD, studies on the effects of airborne heavy metals on newly developed ASD are still limited. We conducted a large birth cohort study of 168,062 live term births in Taichung during 2004-2011 to assess the association of heavy metals in particulate matter with an aerodynamic diameter less than 2.5 μm (PM2.5) with ASD, and identify sensitive time windows during prenatal and postnatal periods. Heavy metals, including arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) in PM2.5, were estimated using the Weather Research and Forecasting/Chem (WRF/Chem), inserted from the top 75 emission sources for the module. The association between childhood ASD and 4 metals were analyzed from pregnancy to 9 months after birth. The Cox proportional hazard model with a distributed lag nonlinear model (DLNM) was used to estimate the association between heavy metals in PM2.5 and ASD. We identified 666 incident ASD cases in 168,062 participants. A positive association between Hg and ASD was found at 9 months after birth (Hazard Ratio: 1.63; 95% CI: 1.13-2.36). According to the DLNM, there was an increased risk of exposure to Hg during 10-25 weeks after birth, and decreased risk of exposure to Hg during gestational weeks 4-6. Exposure to As and Hg on the risk of ASD were significantly stronger in low birth weight infants (<2500 g) than in those of birth weight ≥2500 g during postnatal period. Postnatal exposure to Hg in PM2.5 may associate with increased ASD incidence. Infants with low birth weight and exposure to As and Hg in PM2.5 are more likely to develop ASD.
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Affiliation(s)
- Hao-Hsuan Lin
- Department of Public Health, College of Public Health, China Medical University, Taichung, Taiwan; Institute of Epidemiology and Preventive Medicine, National Taiwan University College of Public Health, Taipei, Taiwan
| | - Chau-Ren Jung
- Department of Public Health, College of Public Health, China Medical University, Taichung, Taiwan; Japan Environment and Children's Study Programme Office, Health and Environmental Risk Division, National Institute for Environmental Studies, Tsukuba, Japan
| | - Chuan-Yao Lin
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan.
| | - Ya-Chu Chang
- Department of Occupational Safety and Health, College of Public Health, China Medical University, Taichung, Taiwan
| | - Chia-Yun Hsieh
- Department of Occupational Safety and Health, College of Public Health, China Medical University, Taichung, Taiwan
| | - Pei-Chuan Hsu
- Department of Occupational Safety and Health, College of Public Health, China Medical University, Taichung, Taiwan
| | - Bao-Ru Chuang
- Department of Occupational Safety and Health, College of Public Health, China Medical University, Taichung, Taiwan
| | - Bing-Fang Hwang
- Department of Occupational Safety and Health, College of Public Health, China Medical University, Taichung, Taiwan; Department of Occupational Therapy, College of Medical and Health Science, Asia University, Taichung, Taiwan.
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Shiani A, Sharafi K, Omer AK, Kiani A, Karamimatin B, Massahi T, Ebrahimzadeh G. A systematic literature review on the association between exposures to toxic elements and an autism spectrum disorder. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159246. [PMID: 36220469 DOI: 10.1016/j.scitotenv.2022.159246] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 09/30/2022] [Accepted: 10/01/2022] [Indexed: 05/16/2023]
Abstract
BACKGROUND AND AIM Autism spectrum disorder (ASD) is a neurodevelopmental illness characterized by difficulties in social communication and repetitive behaviors. There have been many previous studies of toxic metals in ASD. Therefore, the priority of this study is to review the relationships between exposure to toxic metals and ASD. MATERIALS & METHODS This study was based on a comprehensive search of international databases, such as Web of Science, Science Direct, Scopus, PubMed, and Google Scholar, for all works related to the subject under discussion from 1982 to 2022. We further summarize published data linked to this topic and discuss with clarifying evidence that agrees and conflicts with the association between exposure to toxic metals, including mercury (Hg), lead (Pb), cadmium (Cd), arsenic (As), and aluminum (Al) and ASD. RESULTS 40 out of 63 papers met the requirements for meta-analysis. Blood Pb levels (standardized mean difference (SMD) = 0.81; 95 % confidence interval (CI): 0.36-1.25), blood Hg (SMD = 0.90; CI: 0.30-1.49), hair Pb (SMD = 1.47; CI: 0.03-2.92), urine As (SMD = 0.65; CI: 0.22-1.09), and urine Al levels (SMD = 0.85; CI: 0.40-1.29) in autistic individuals were significantly higher than those of healthy control (HC). Whereas, blood As levels (SMD = 1.33; CI: -1.32-3.97), hair As (SMD = 0.55; CI: -0.14-1.24), hair Cd (SMD = 0.60; CI: -0.31-1.51), hair Hg (SMD = 0.41; CI: -0.30-1.12), hair Al (SMD = 0.87; CI: -0.02-1.77), urine Pb (SMD = -0.68; CI: -2.55-1.20), urine Cd (SMD = -0.26; CI: -0.94-0.41), and urine Hg levels (SMD = 0.47; CI: -0.09-1.04) in autistic individuals were significantly lower than those of HC. CONCLUSION Toxic metal content significantly differed between individuals with ASD and HC in the current meta-analysis. The results assist in clarifying the significance of toxic metals as environmental factors in the development of ASD.
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Affiliation(s)
- Amir Shiani
- Department of Speech Therapy, School of Rehabilitation Sciences, Kermanshah University of Medical Sciences, Kermanshah, Iran; Clinical Research Development Center, Taleghani and Imam Ali Hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Kiomars Sharafi
- Research Center for Environmental Determinants of Health (RCEDH), Research Institute for Health, Kermanshah University of Medical Sciences, Kermanshah, Iran; Department of Environmental Health Engineering, School of Public Health, Kermanshah University of Medical Sciences, Kermanshah, Iran.
| | - Abdullah Khalid Omer
- Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran; Razga Company, Kurdistan Region, Iraq.
| | - Amir Kiani
- Regenerative Medicine Research Center (RMRC), Kermanshah University of Medical Sciences, Kermanshah, Iran; Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Behzad Karamimatin
- Research Center for Environmental Determinants of Health (RCEDH), Research Institute for Health, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Tooraj Massahi
- Students Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Gholamreza Ebrahimzadeh
- Department of Environmental Health Engineering, School of Public Health, Zabol University of Medical Sciences, Zabol, Iran
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Erden S, Akbaş İleri B, Sadıç Çelikkol Ç, Nalbant K, Kılınç İ, Yazar A. Serum B12, homocysteine, and anti-parietal cell antibody levels in children with autism. Int J Psychiatry Clin Pract 2022; 26:8-13. [PMID: 33823740 DOI: 10.1080/13651501.2021.1906906] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AIMS To compare vitamin B12, homocysteine, and anti-parietal cell antibody (APCA) levels between children with ASD and controls, paired in terms of age, sex, and socioeconomic level. METHODS The research group consisted of 69 children, 36 with ASD and 33 controls. The severity of ASD was determined using the Childhood Autism Rating Scale (CARS). Serum vitamin B12, homocysteine and human anti-parietal cell levels were analysed using enzyme-linked immunosorbent assay. RESULTS The serum vitamin B12 and homocysteine levels in children with ASD were lower than in the control group, but there was no significant difference in terms of APCA levels. CONCLUSIONS Deficiencies in micronutrients, such as B12, may play a role in the pathogenesis and clinical symptoms of autism. However, it is believed that these parameters should be analysed in a wider population to clarify their effect on the aetiology of ASD.KEY POINTWe hypothesised that low levels of vitamin B12 and homocysteine levels reported in previous studies might be associated with APCA levels.The homocysteine and B12 levels were found to be significantly lower in children with ASD. There was no significant difference in serum APCA levels.No significant relationship was found between B12 levels and APCA.Given all these findings, it can be stated that vitamin B12 deficiency is not associated with an absorption-related mechanism due to the presence of APCA.Deficiencies in micronutrients, such as B12, may play a role in the pathogenesis and clinical symptoms of autism.In future studies, it will be beneficial to investigate other mechanisms that may cause vitamin B12 deficiency.
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Affiliation(s)
- Semih Erden
- Department of Child and Adolescent Psychiatry, Necmettin Erbakan University Faculty of Medicine, Konya, Turkey
| | - Betül Akbaş İleri
- Department of Child and Adolescent Psychiatry, Necmettin Erbakan University Faculty of Medicine, Konya, Turkey
| | - Çağla Sadıç Çelikkol
- Department of Child and Adolescent Psychiatry, Necmettin Erbakan University Faculty of Medicine, Konya, Turkey
| | - Kevser Nalbant
- Department of Child and Adolescent Psychiatry, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - İbrahim Kılınç
- Department of Biochemistry, Necmettin Erbakan University Faculty of Medicine, Konya, Turkey
| | - Abdullah Yazar
- Department of Child Health and Diseases, Necmettin Erbakan University Faculty of Medicine, Konya, Turkey
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Methylmercury chloride exposure exacerbates existing neurobehavioral and immune dysfunctions in the BTBR T+ Itpr3tf/J mouse model of autism. Immunol Lett 2022; 244:19-27. [DOI: 10.1016/j.imlet.2022.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/03/2022] [Accepted: 03/04/2022] [Indexed: 12/15/2022]
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Zhang J, Li X, Shen L, Khan NU, Zhang X, Chen L, Zhao H, Luo P. Trace elements in children with autism spectrum disorder: A meta-analysis based on case-control studies. J Trace Elem Med Biol 2021; 67:126782. [PMID: 34049201 DOI: 10.1016/j.jtemb.2021.126782] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 03/30/2021] [Accepted: 05/10/2021] [Indexed: 12/25/2022]
Abstract
Autism spectrum disorder (ASD) is a common childhood neurodevelopmental disorder that may be related to trace elements. However, reports on the relationship between them are still inconsistent. In this article, we conducted a meta-analysis on this issue. We searched the PubMed, EMBASE, and Cochrane databases as of November 15, 2019. A random-effects model was used, and subgroups of studies were analyzed using samples of different measurements. Twenty-two original articles were identified (18 trace elements, including a total of 1014 children with ASD and 999 healthy controls). In autistic children, the overall levels of barium (Ba), mercury (Hg), lithium (Li), and lead (Pb) were higher. There were significant differences in the levels of copper (Cu) in the hair and serum between autistic children and the control group. The levels of Hg, Li, Pb and selenium (Se) in the hair of autistic children were higher than those of healthy children, while the levels of zinc (Zn) in the blood were lower. Excessive exposure to toxic heavy metals and inadequate intake of essential metal elements may be associated with ASD. Preventing excessive exposure to toxic metals and correcting poor dietary behaviors may be beneficial for the prevention and treatment of the disease.
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Affiliation(s)
- Jun Zhang
- School of Public Health, Key Laboratory of Environmental Pollution Monitoring Control Ministry of Education, Guizhou Medical University, 550025, PR China
| | - Xi Li
- School of Public Health, Key Laboratory of Environmental Pollution Monitoring Control Ministry of Education, Guizhou Medical University, 550025, PR China
| | - Liming Shen
- College of Life Science and Oceanography, Shenzhen University, Shenzhen, 518060, PR China; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, PR China.
| | - Naseer Ullah Khan
- College of Life Science and Oceanography, Shenzhen University, Shenzhen, 518060, PR China
| | - Xiao Zhang
- School of Public Health, Key Laboratory of Environmental Pollution Monitoring Control Ministry of Education, Guizhou Medical University, 550025, PR China
| | - Lulu Chen
- School of Public Health, Key Laboratory of Environmental Pollution Monitoring Control Ministry of Education, Guizhou Medical University, 550025, PR China
| | - Huan Zhao
- School of Public Health, Key Laboratory of Environmental Pollution Monitoring Control Ministry of Education, Guizhou Medical University, 550025, PR China
| | - Peng Luo
- School of Public Health, Key Laboratory of Environmental Pollution Monitoring Control Ministry of Education, Guizhou Medical University, 550025, PR China; State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, PR China.
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Baj J, Flieger W, Flieger M, Forma A, Sitarz E, Skórzyńska-Dziduszko K, Grochowski C, Maciejewski R, Karakuła-Juchnowicz H. Autism spectrum disorder: Trace elements imbalances and the pathogenesis and severity of autistic symptoms. Neurosci Biobehav Rev 2021; 129:117-132. [PMID: 34339708 DOI: 10.1016/j.neubiorev.2021.07.029] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 02/08/2023]
Abstract
The identification of biomarkers as diagnostic tools and predictors of response to treatment of neurological developmental disorders (NDD) such as schizophrenia (SZ), attention deficit hyperactivity disorder (ADHD), or autism spectrum disorder (ASD), still remains an important challenge for clinical medicine. Metallomic profiles of ASD patients cover, besides essential elements such as cobalt, chromium, copper, iron, manganese, molybdenum, zinc, selenium, also toxic metals burden of: aluminum, arsenic, mercury, lead, beryllium, nickel, cadmium. Performed studies indicate that children with ASD present a reduced ability of eliminating toxic metals, which leads to these metals' accumulation and aggravation of autistic symptoms. Extensive metallomic studies allow a better understanding of the importance of trace elements as environmental factors in the pathogenesis of ASD. Even though a mineral imbalance is a fact in ASD, we are still expecting relevant tests and the elaboration of reference levels of trace elements as potential biomarkers useful in diagnosis, prevention, and treatment of ASD.
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Affiliation(s)
- Jacek Baj
- Department of Anatomy, Medical University of Lublin, Jaczewskiego Street 8b, 20-400, Lublin, Poland.
| | - Wojciech Flieger
- Faculty of Medicine, Medical University of Lublin, Aleje Racławickie 1, 20-059, Lublin, Poland
| | - Michał Flieger
- Faculty of Medicine, Medical University of Lublin, Aleje Racławickie 1, 20-059, Lublin, Poland
| | - Alicja Forma
- Chair and Department of Forensic Medicine, Medical University of Lublin, Jaczewskiego Street 8b, 20-090, Lublin, Poland
| | - Elżbieta Sitarz
- Chair and 1st Department of Psychiatry, Psychotherapy and Early Intervention, Medical University of Lublin, Gluska Street 1, 20-439, Lublin, Poland
| | - Katarzyna Skórzyńska-Dziduszko
- Chair and Department of Human Physiology, Medical University of Lublin, Radziwillowska Street 11, Lublin, 20-080, Poland
| | - Cezary Grochowski
- Laboratory of Virtual Man, Chair of Anatomy, Medical University of Lublin, Jaczewskiego Street 8b, 20-400, Lublin, Poland
| | - Ryszard Maciejewski
- Department of Anatomy, Medical University of Lublin, Jaczewskiego Street 8b, 20-400, Lublin, Poland
| | - Hanna Karakuła-Juchnowicz
- Chair and 1st Department of Psychiatry, Psychotherapy and Early Intervention, Medical University of Lublin, Gluska Street 1, 20-439, Lublin, Poland; Department of Clinical Neuropsychiatry, Medical University of Lublin, Gluska Street 1, 20-439, Lublin, Poland
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Indika NLR, Deutz NEP, Engelen MPKJ, Peiris H, Wijetunge S, Perera R. Sulfur amino acid metabolism and related metabotypes of autism spectrum disorder: A review of biochemical evidence for a hypothesis. Biochimie 2021; 184:143-157. [PMID: 33675854 DOI: 10.1016/j.biochi.2021.02.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 02/07/2023]
Abstract
There are multiple lines of evidence for an impaired sulfur amino acid (SAA) metabolism in autism spectrum disorder (ASD). For instance, the concentrations of methionine, cysteine and S-adenosylmethionine (SAM) in body fluids of individuals with ASD is significantly lower while the concentration of S-adenosylhomocysteine (SAH) is significantly higher as compared to healthy individuals. Reduced methionine and SAM may reflect impaired remethylation pathway whereas increased SAH may reflect reduced S-adenosylhomocysteine hydrolase activity in the catabolic direction. Reduced SAM/SAH ratio reflects an impaired methylation capacity. We hypothesize multiple mechanisms to explain how the interplay of oxidative stress, neuroinflammation, mercury exposure, maternal use of valproate, altered gut microbiome and certain genetic variants may lead to these SAA metabotypes. Furthermore, we also propose a number of mechanisms to explain the metabolic consequences of abnormal SAA metabotypes. For instance in the brain, reduced SAM/SAH ratio will result in melatonin deficiency and hypomethylation of a number of biomolecules such as DNA, RNA and histones. In addition to previously proposed mechanisms, we propose that impaired activity of "radical SAM" enzymes will result in reduced endogenous lipoic acid synthesis, reduced molybdenum cofactor synthesis and impaired porphyrin metabolism leading to mitochondrial dysfunction, porphyrinuria and impaired sulfation capacity. Furthermore depletion of SAM may also lead to the disturbed mTOR signaling pathway in a subgroup of ASD. The proposed "SAM-depletion hypothesis" is an inclusive model to explain the relationship between heterogeneous risk factors and metabotypes observed in a subset of children with ASD.
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Affiliation(s)
- Neluwa-Liyanage R Indika
- Department of Biochemistry, Faculty of Medical Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka.
| | - Nicolaas E P Deutz
- Center for Translational Research in Aging & Longevity, Department of Health & Kinesiology, Texas A&M University, College Station, TX, USA
| | - Marielle P K J Engelen
- Center for Translational Research in Aging & Longevity, Department of Health & Kinesiology, Texas A&M University, College Station, TX, USA
| | - Hemantha Peiris
- Department of Biochemistry, Faculty of Medical Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka
| | - Swarna Wijetunge
- Child and Adolescent Mental Health Service, Lady Ridgeway Hospital for Children, Colombo 8, Sri Lanka
| | - Rasika Perera
- Department of Biochemistry, Faculty of Medical Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka
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10
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Bjørklund G, Doşa MD, Maes M, Dadar M, Frye RE, Peana M, Chirumbolo S. The impact of glutathione metabolism in autism spectrum disorder. Pharmacol Res 2021; 166:105437. [PMID: 33493659 DOI: 10.1016/j.phrs.2021.105437] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 12/31/2020] [Accepted: 01/12/2021] [Indexed: 12/14/2022]
Abstract
This paper reviews the potential role of glutathione (GSH) in autism spectrum disorder (ASD). GSH plays a key role in the detoxification of xenobiotics and maintenance of balance in intracellular redox pathways. Recent data showed that imbalances in the GSH redox system are an important factor in the pathophysiology of ASD. Furthermore, ASD is accompanied by decreased concentrations of reduced GSH in part caused by oxidation of GSH into glutathione disulfide (GSSG). GSSG can react with protein sulfhydryl (SH) groups, thereby causing proteotoxic stress and other abnormalities in SH-containing enzymes in the brain and blood. Moreover, alterations in the GSH metabolism via its effects on redox-independent mechanisms are other processes associated with the pathophysiology of ASD. GSH-related regulation of glutamate receptors such as the N-methyl-D-aspartate receptor can contribute to glutamate excitotoxicity. Synergistic and antagonistic interactions between glutamate and GSH can result in neuronal dysfunction. These interactions can involve transcription factors of the immune pathway, such as activator protein 1 and nuclear factor (NF)-κB, thereby interacting with neuroinflammatory mechanisms, ultimately leading to neuronal damage. Neuronal apoptosis and mitochondrial dysfunction are recently outlined as significant factors linking GSH impairments with the pathophysiology of ASD. Moreover, GSH regulates the methylation of DNA and modulates epigenetics. Existing data support a protective role of the GSH system in ASD development. Future research should focus on the effects of GSH redox signaling in ASD and should explore new therapeutic approaches by targeting the GSH system.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine (CONEM), Toften 24, 8610, Mo i Rana, Norway.
| | - Monica Daniela Doşa
- Department of Pharmacology, Faculty of Medicine, Ovidius University of Constanta, Campus, 900470, Constanta, Romania.
| | - Michael Maes
- Department of Psychiatry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; Impact Research Center, Deakin University, Geelong, Australia
| | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Richard E Frye
- Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ, USA; Department of Child Health, University of Arizona College of Medicine, Phoenix, AZ, USA
| | | | - Salvatore Chirumbolo
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy; CONEM Scientific Secretary, Verona, Italy
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Bjørklund G, Tinkov AA, Hosnedlová B, Kizek R, Ajsuvakova OP, Chirumbolo S, Skalnaya MG, Peana M, Dadar M, El-Ansary A, Qasem H, Adams JB, Aaseth J, Skalny AV. The role of glutathione redox imbalance in autism spectrum disorder: A review. Free Radic Biol Med 2020; 160:149-162. [PMID: 32745763 DOI: 10.1016/j.freeradbiomed.2020.07.017] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 07/02/2020] [Accepted: 07/13/2020] [Indexed: 12/22/2022]
Abstract
The role of glutathione in autism spectrum disorder (ASD) is emerging as a major topic, due to its role in the maintenance of the intracellular redox balance. Several studies have implicated glutathione redox imbalance as a leading factor in ASD, and both ASD and many other neurodevelopmental disorders involve low levels of reduced glutathione (GSH), high levels of oxidized glutathione (GSSG), and abnormalities in the expressions of glutathione-related enzymes in the blood or brain. Glutathione metabolism, through its impact on redox environment or redox-independent mechanisms, interferes with multiple mechanisms involved in ASD pathogenesis. Glutathione-mediated regulation of glutamate receptors [e.g., N-methyl-d-aspartate (NMDA) receptor], as well as the role of glutamate as a substrate for glutathione synthesis, may be involved in the regulation of glutamate excitotoxicity. However, the interaction between glutathione and glutamate in the pathogenesis of brain diseases may vary from synergism to antagonism. Modulation of glutathione is also associated with regulation of redox-sensitive transcription factors nuclear factor kappa B (NF-κB) and activator protein 1 (AP-1) and downstream signaling (proinflammatory cytokines and inducible enzymes), thus providing a significant impact on neuroinflammation. Mitochondrial dysfunction, as well as neuronal apoptosis, may also provide a significant link between glutathione metabolism and ASD. Furthermore, it has been recently highlighted that glutathione can affect and modulate DNA methylation and epigenetics. Review analysis including research studies meeting the required criteria for analysis showed statistically significant differences between the plasma GSH and GSSG levels as well as GSH:GSSG ratio in autistic patients compared with healthy individuals (P = 0.0145, P = 0.0150 and P = 0.0202, respectively). Therefore, the existing data provide a strong background on the role of the glutathione system in ASD pathogenesis. Future research is necessary to investigate the role of glutathione redox signaling in ASD, which could potentially also lead to promising therapeutics.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine (CONEM), Mo I Rana, Norway.
| | - Alexey A Tinkov
- IM Sechenov First Moscow State Medical University, Moscow, Russia; Yaroslavl State University, Yaroslavl, Russia; Federal Research Centre of Biological Systems, Agro-technologies of the Russian Academy of Sciences, Orenburg, Russia
| | - Božena Hosnedlová
- Department of Human Pharmacology and Toxicology, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic; CONEM Metallomics Nanomedicine Research Group (CMNRG), Brno, Czech Republic
| | - Rene Kizek
- Department of Human Pharmacology and Toxicology, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic; CONEM Metallomics Nanomedicine Research Group (CMNRG), Brno, Czech Republic; Faculty of Pharmacy with Division of Laboratory Medicine, Wroclaw Medical University, Wroclaw, Poland
| | - Olga P Ajsuvakova
- IM Sechenov First Moscow State Medical University, Moscow, Russia; Yaroslavl State University, Yaroslavl, Russia; Federal Research Centre of Biological Systems, Agro-technologies of the Russian Academy of Sciences, Orenburg, Russia
| | - Salvatore Chirumbolo
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy; CONEM Scientific Secretary, Verona, Italy
| | - Margarita G Skalnaya
- IM Sechenov First Moscow State Medical University, Moscow, Russia; Federal Research Centre of Biological Systems, Agro-technologies of the Russian Academy of Sciences, Orenburg, Russia
| | | | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Afaf El-Ansary
- Medicinal Chemistry Department, King Saud University, Riyadh, Saudi Arabia; Autism Research and Treatment Center, Riyadh, Saudi Arabia; CONEM Saudi Autism Research Group, King Saud University, Riyadh, Saudi Arabia
| | - Hanan Qasem
- Autism Research and Treatment Center, Riyadh, Saudi Arabia; CONEM Saudi Autism Research Group, King Saud University, Riyadh, Saudi Arabia
| | - James B Adams
- School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ, USA
| | - Jan Aaseth
- Research Department, Innlandet Hospital Trust, Brumunddal, Norway
| | - Anatoly V Skalny
- IM Sechenov First Moscow State Medical University, Moscow, Russia; Federal Research Centre of Biological Systems, Agro-technologies of the Russian Academy of Sciences, Orenburg, Russia
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12
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Sulaiman R, Wang M, Ren X. Exposure to Aluminum, Cadmium, and Mercury and Autism Spectrum Disorder in Children: A Systematic Review and Meta-Analysis. Chem Res Toxicol 2020; 33:2699-2718. [DOI: 10.1021/acs.chemrestox.0c00167] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Rosalind Sulaiman
- Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, The State University of New York, Buffalo, New York 14214, United States
| | - Meng Wang
- Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, The State University of New York, Buffalo, New York 14214, United States
- Research and Education in Energy, Environment and Water Institute, University at Buffalo, Buffalo, New York 14260, United States
| | - Xuefeng Ren
- Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, The State University of New York, Buffalo, New York 14214, United States
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, The State University of New York, Buffalo, New York 14214, United States
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Blood homocysteine levels in children with autism spectrum disorder: An updated systematic review and meta-analysis. Psychiatry Res 2020; 291:113283. [PMID: 32763544 DOI: 10.1016/j.psychres.2020.113283] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/11/2020] [Accepted: 07/05/2020] [Indexed: 12/24/2022]
Abstract
Results of studies on peripheral blood levels of homocysteine (Hcy) in children with autism spectrum disorder (ASD) are inconsistent, and conclusions from two previous meta-analyses on this subject published in 2012 are already outdated. Therefore, we conducted an updated systematic review and meta-analysis to quantitatively summarize the peripheral blood Hcy data in children with ASD compared with healthy controls (HC). We searched PubMed, EMBASE, PsycINFO, PsycARTICLES, Web of Science, and Cochrane Library databases from inception to September 2019 for eligible studies, with no language restriction. Using random-effects model, we computed summary statistics. Thirty-one studies (3304 participants including 1641 cases) were included. The pooled results showed that the peripheral blood Hcy levels were significantly elevated in children with ASD when compared to HC (Hedges's g = 0.56, 95% CI = 0.36 to 0.76, P < 0.001). By sensitivity analyses, we confirmed that our results were quite robust. Additionally, no publication bias was observed in this meta-analysis. In conclusion, our study support the association of increased circulating Hcy levels with ASD in children, and the involvement of Hcy in the occurrence of ASD. However, in view of the significant between-study heterogeneity, the conclusions should be interpreted cautiously and more investigation is required.
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Guo BQ, Ding SB, Li HB. Blood biomarker levels of methylation capacity in autism spectrum disorder: a systematic review and meta-analysis. Acta Psychiatr Scand 2020; 141:492-509. [PMID: 32173856 DOI: 10.1111/acps.13170] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/11/2020] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To compare the peripheral blood levels of methionine (Met), S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and the SAM/SAH ratio (the most core and predictive indices of cellular methylation ability) between patients with autism spectrum disorder (ASD) and control subjects. METHODS PubMed, Embase, PsycINFO, Web of Science, and Cochrane Library were searched from inception to August 2, 2019, without language restriction. The random-effects model was used to summarize effect sizes. RESULTS We retrieved 1,493 records, of which 22 studies met inclusion criteria. Our overall analyses revealed that individuals with ASD had significantly decreased levels of Met (22 studies; Hedges' g = -0.62; 95% confidence interval [CI]: -0.89, -0.35), SAM (8 studies; Hedges' g = -0.60; 95% CI: -0.86, -0.34), and the SAM/SAH ratio (8 studies; Hedges' g = -0.98; 95% CI: -1.30, -0.66) and significantly increased levels of SAH (8 studies; Hedges' g = 0.69; 95% CI: 0.43, 0.94). The findings of the overall analyses were quite stable after being verified by sensitivity analyses and in agreement with the corresponding outcomes of subgroup analyses. Additionally, our results from meta-analytic techniques confirmed that the effect estimates of this meta-analysis did not originate from publication bias. CONCLUSION Individuals with ASD have substantially aberrant peripheral blood levels of Met, SAM, SAH, and the SAM/SAH ratio, which supports the association between impaired methylation capacity and ASD. Therefore, further investigations into these indices as potential biomarkers for diagnosis and therapeutic targets of ASD are warranted.
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Affiliation(s)
- Bao-Qiang Guo
- Department of Child and Adolescent Health, School of Public Health, Xinxiang Medical University, Xinxiang, Henan, China
| | - Shi-Bin Ding
- Department of Nutrition and Food Hygiene, School of Public Health, Xinxiang Medical University, Xinxiang, Henan, China
| | - Hong-Bin Li
- Department of Child and Adolescent Health, School of Public Health, Xinxiang Medical University, Xinxiang, Henan, China
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Bjørklund G, Meguid NA, El-Bana MA, Tinkov AA, Saad K, Dadar M, Hemimi M, Skalny AV, Hosnedlová B, Kizek R, Osredkar J, Urbina MA, Fabjan T, El-Houfey AA, Kałużna-Czaplińska J, Gątarek P, Chirumbolo S. Oxidative Stress in Autism Spectrum Disorder. Mol Neurobiol 2020; 57:2314-2332. [PMID: 32026227 DOI: 10.1007/s12035-019-01742-2] [Citation(s) in RCA: 134] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 08/19/2019] [Indexed: 02/07/2023]
Abstract
According to the United States Centers for Disease Control and Prevention (CDC), as of July 11, 2016, the reported average incidence of children diagnosed with an autism spectrum disorder (ASD) was 1 in 68 (1.46%) among 8-year-old children born in 2004 and living within the 11 monitoring sites' surveillance areas in the United States of America (USA) in 2012. ASD is a multifaceted neurodevelopmental disorder that is also considered a hidden disability, as, for the most part; there are no apparent morphological differences between children with ASD and typically developing children. ASD is diagnosed based upon a triad of features including impairment in socialization, impairment in language, and repetitive and stereotypic behaviors. The increasing incidence of ASD in the pediatric population and the lack of successful curative therapies make ASD one of the most challenging disorders for medicine. ASD neurobiology is thought to be associated with oxidative stress, as shown by increased levels of reactive oxygen species and increased lipid peroxidation, as well as an increase in other indicators of oxidative stress. Children with ASD diagnosis are considered more vulnerable to oxidative stress because of their imbalance in intracellular and extracellular glutathione levels and decreased glutathione reserve capacity. Several studies have suggested that the redox imbalance and oxidative stress are integral parts of ASD pathophysiology. As such, early assessment and treatment of antioxidant status may result in a better prognosis as it could decrease the oxidative stress in the brain before it can induce more irreversible brain damage. In this review, many aspects of the role of oxidative stress in ASD are discussed, taking into account that the process of oxidative stress may be a target for therapeutic interventions.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine (CONEM), Toften 24, 8610, Mo i Rana, Norway.
| | - Nagwa A Meguid
- Research on Children with Special Needs Department, National Research Centre, Giza, Egypt
- CONEM Egypt Child Brain Research Group, National Research Center, Giza, Egypt
| | - Mona A El-Bana
- CONEM Egypt Child Brain Research Group, National Research Center, Giza, Egypt
- Medical Biochemistry Department, National Research Centre, Giza, Egypt
| | - Alexey A Tinkov
- Yaroslavl State University, Yaroslavl, Russia
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia
- IM Sechenov First Moscow State Medical University, Moscow, Russia
| | - Khaled Saad
- Department of Pediatrics, Faculty of Medicine, Assiut University, Assiut, Egypt
- CONEM Upper Egypt Pediatric Research Group, Assiut University, Assiut, Egypt
| | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Maha Hemimi
- Research on Children with Special Needs Department, National Research Centre, Giza, Egypt
- CONEM Egypt Child Brain Research Group, National Research Center, Giza, Egypt
| | - Anatoly V Skalny
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia
- IM Sechenov First Moscow State Medical University, Moscow, Russia
- Federal Research Centre of Biological Systems and Agro-technologies of the Russian Academy of Sciences, Orenburg, Russia
- Taipei Medical University, Taipei, Taiwan
| | - Božena Hosnedlová
- CONEM Metallomics Nanomedicine Research Group (CMNRG), Brno, Czech Republic
- Faculty of Pharmacy, Department of Human Pharmacology and Toxicology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Rene Kizek
- CONEM Metallomics Nanomedicine Research Group (CMNRG), Brno, Czech Republic
- Faculty of Pharmacy, Department of Human Pharmacology and Toxicology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Joško Osredkar
- Institute of Clinical Chemistry and Biochemistry (KIKKB), Ljubljana University Medical Centre, Ljubljana, Slovenia
| | - Mauricio A Urbina
- Departamento de Zoología, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Concepción, Chile
| | - Teja Fabjan
- Institute of Clinical Chemistry and Biochemistry (KIKKB), Ljubljana University Medical Centre, Ljubljana, Slovenia
| | - Amira A El-Houfey
- CONEM Upper Egypt Pediatric Research Group, Assiut University, Assiut, Egypt
- Department of Community Health Nursing, Faculty of Nursing, Assiut University, Assiut, Egypt
- Department of Community Health Nursing, Sabia University College, Jazan University, Jizan, Saudi Arabia
| | - Joanna Kałużna-Czaplińska
- Institute of General and Ecological Chemistry, Department of Chemistry, Technical University of Lodz, Lodz, Poland
- CONEM Poland Chemistry and Nutrition Research Group, Lodz University of Technology, Lodz, Poland
| | - Paulina Gątarek
- Institute of General and Ecological Chemistry, Department of Chemistry, Technical University of Lodz, Lodz, Poland
- CONEM Poland Chemistry and Nutrition Research Group, Lodz University of Technology, Lodz, Poland
| | - Salvatore Chirumbolo
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
- CONEM Scientific Secretary, Verona, Italy
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Sa-Carneiro F, Calhau C, Coelho R, Figueiredo-Braga M. Putative shared mechanisms in autism spectrum disorders and attention deficit hyperactivity disorder, a systematic review of the role of oxidative stress. Acta Neurobiol Exp (Wars) 2020. [DOI: 10.21307/ane-2020-013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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17
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Wang G, DiBari J, Bind E, Steffens AM, Mukherjee J, Bartell TR, Bellinger DC, Hong X, Ji Y, Wang MC, Wills-Karp M, Cheng TL, Wang X. In utero exposure to mercury and childhood overweight or obesity: counteracting effect of maternal folate status. BMC Med 2019; 17:216. [PMID: 31775748 PMCID: PMC6882077 DOI: 10.1186/s12916-019-1442-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 10/07/2019] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Low-dose mercury (Hg) exposure has been associated with cardiovascular diseases, diabetes, and obesity in adults, but it is unknown the metabolic consequence of in utero Hg exposure. This study aimed to investigate the association between in utero Hg exposure and child overweight or obesity (OWO) and to explore if adequate maternal folate can mitigate Hg toxicity. METHODS This prospective study included 1442 mother-child pairs recruited at birth and followed up to age 15 years. Maternal Hg in red blood cells and plasma folate levels were measured in samples collected 1-3 days after delivery (a proxy for third trimester exposure). Adequate folate was defined as plasma folate ≥ 20.4 nmol/L. Childhood OWO was defined as body mass index ≥ 85% percentile for age and sex. RESULTS The median (interquartile range) of maternal Hg levels were 2.11 (1.04-3.70) μg/L. Geometric mean (95% CI) of maternal folate levels were 31.1 (30.1-32.1) nmol/L. Maternal Hg levels were positively associated with child OWO from age 2-15 years, independent of maternal pre-pregnancy OWO, diabetes, and other covariates. The relative risk (RR = 1.24, 95% CI 1.05-1.47) of child OWO associated with the highest quartile of Hg exposure was 24% higher than those with the lowest quartile. Maternal pre-pregnancy OWO and/or diabetes additively enhanced Hg toxicity. The highest risk of child OWO was found among children of OWO and diabetic mothers in the top Hg quartile (RR = 2.06; 95% CI 1.56-2.71) compared to their counterparts. Furthermore, adequate maternal folate status mitigated Hg toxicity. Given top quartile Hg exposure, adequate maternal folate was associated with a 34% reduction in child OWO risk (RR = 0.66, 95% CI 0.51-0.85) as compared with insufficient maternal folate. There was a suggestive interaction between maternal Hg and folate levels on child OWO risk (p for interaction = 0.086). CONCLUSIONS In this US urban, multi-ethnic population, elevated in utero Hg exposure was associated with a higher risk of OWO in childhood, and such risk was enhanced by maternal OWO and/or diabetes and reduced by adequate maternal folate. These findings underscore the need to screen for Hg and to optimize maternal folate status, especially among mothers with OWO and/or diabetes.
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Affiliation(s)
- Guoying Wang
- Department of Population, Family and Reproductive Health, Center on the Early Life Origins of Disease, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205-2179, USA.
| | - Jessica DiBari
- Division of Research, Office of Epidemiology and Research, Maternal and Child Health Bureau, Health Resources and Services Administration, 5600 Fishers Ln, Rockville, MD, 20852, USA
| | - Eric Bind
- Metals Laboratory, Environmental and Chemical Laboratory Services, The New Jersey Department of Health, Trenton, NJ, 08628, USA
| | - Andrew M Steffens
- Metals Laboratory, Environmental and Chemical Laboratory Services, The New Jersey Department of Health, Trenton, NJ, 08628, USA
| | - Jhindan Mukherjee
- Metals Laboratory, Environmental and Chemical Laboratory Services, The New Jersey Department of Health, Trenton, NJ, 08628, USA
| | - Tami R Bartell
- Mary Ann & J. Milburn Smith Child Health Research, Outreach and Advocacy Center, Stanley Manne Children's Research Institute, Ann & Robert H Lurie Children's Hospital of Chicago, 2430 N Halsted St, Chicago, IL, 60614, USA
| | - David C Bellinger
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA
| | - Xiumei Hong
- Department of Population, Family and Reproductive Health, Center on the Early Life Origins of Disease, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205-2179, USA
| | - Yuelong Ji
- Department of Population, Family and Reproductive Health, Center on the Early Life Origins of Disease, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205-2179, USA
| | - Mei-Cheng Wang
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe street, Baltimore, MD, 21205, USA
| | - Marsha Wills-Karp
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe street, Baltimore, MD, 21205, USA
| | - Tina L Cheng
- Department of Pediatrics, Johns Hopkins School of Medicine, 615 N. Wolfe street, Baltimore, MD, 21205, USA
| | - Xiaobin Wang
- Department of Population, Family and Reproductive Health, Center on the Early Life Origins of Disease, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205-2179, USA
- Department of Pediatrics, Johns Hopkins School of Medicine, 615 N. Wolfe street, Baltimore, MD, 21205, USA
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Alhowikan AM, AL-Ayadhi LY, Halepoto DM. Impact of environmental pollution, dietary factors and diabetes mellitus on Autism Spectrum Disorder (ASD). Pak J Med Sci 2019; 35:1179-1184. [PMID: 31372164 PMCID: PMC6659068 DOI: 10.12669/pjms.35.4.269] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 02/05/2019] [Accepted: 05/26/2019] [Indexed: 02/06/2023] Open
Abstract
Autism spectrum disorder (ASD) is complex neurodevelopmental condition described by impairments in three main behavioral areas: social deficits, impaired communication, and repetitive behaviors. Despite many years of vast study, the causes of ASD are still unknown. Various risk factors including genetic, infectious, metabolic and immunological have been investigated however, environmental, nutritional and diabetes related risk factors have not received sufficient attention. This study has provided an insight into the comprehensive interaction between environmental pollution, dietary factors and diabetes mellitus that could lead to the advancement of this debilitating neurodevelopment disorder. The literature search was done using PubMed and Google Scholar databases up to October 2018. Key words "Environmental Pollution", "Nutritional Factors", "Diabetes Mellitus", "Autism Spectrum Disorder" were selected.
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Affiliation(s)
- Abdulrahman Mohammed Alhowikan
- Abdulrahman Mohammed Alhowikan, PhD. Department of Physiology, Faculty of Medicine, King Saud University, P O Box 2925, Riyadh 11461 and Saudi Arabia
| | - Laila Yousef AL-Ayadhi
- Laila Yousef AL-Ayadhi, MBBS, PhD. Autism Research and Treatment Center, Department of physiology, Faculty of Medicine, King Saud University, P O Box 2925, Riyadh 11461 and Saudi Arabia
| | - Dost Muhammad Halepoto
- Dost Muhammad Halepoto, PhD. Autism Research and Treatment Center, Department of Physiology, Faculty of Medicine, King Saud University, P O Box 2925, Riyadh 11461 and Saudi Arabia
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Guo BQ, Li HB, Liu YY. Association between hair lead levels and autism spectrum disorder in children: A systematic review and meta-analysis. Psychiatry Res 2019; 276:239-249. [PMID: 31121530 DOI: 10.1016/j.psychres.2019.05.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 05/11/2019] [Indexed: 01/08/2023]
Abstract
A number of studies measured lead levels in hair from children with autism spectrum disorder (ASD) to detect the relationship between cumulated lead exposure and the development of ASD, but results are inconsistent. We aimed to conduct a systematic review and meta-analysis using the published studies to explore the actual association of hair lead levels with ASD in children. We searched PubMed, Embase, PsycINFO, and Cochrane Library databases (up to December 11, 2018). The random-effects model was applied to summarize effect sizes. Subgroup and meta-regression analyses were performed simultaneously. Twenty eligible studies involving 1787 participants (941 autistic children and 846 healthy subjects) were included. Our results of primary analysis showed that there were no statistically significant differences in the levels of hair lead between children with ASD and healthy individuals (Hedges's g = 0.251; 95% confidence interval: -0.121, 0.623; P = 0.187). We identified 2 sources of between-study heterogeneity: analytical technology and the sample size of patients. Additionally, no publication bias was observed in this meta-analysis. In conclusion, this study does not support the association of hair lead levels with ASD in children, and the involvement of cumulated lead exposure in the occurrence of ASD.
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Affiliation(s)
- Bao-Qiang Guo
- Department of Child and Adolescent Health, School of Public Health, Xinxiang Medical University, 601 Jinsui Road, Xinxiang, Henan 453003, China.
| | - Hong-Bin Li
- Department of Child and Adolescent Health, School of Public Health, Xinxiang Medical University, 601 Jinsui Road, Xinxiang, Henan 453003, China
| | - Ying-Ying Liu
- Key Laboratory of Environmental Pollutants and Health Effects Assessment, School of Public Health, Xinxiang Medical University, Xinxiang, Henan 453003, China
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20
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Nadeem A, Ahmad SF, Al-Harbi NO, Attia SM, Alshammari MA, Alzahrani KS, Bakheet SA. Increased oxidative stress in the cerebellum and peripheral immune cells leads to exaggerated autism-like repetitive behavior due to deficiency of antioxidant response in BTBR T + tf/J mice. Prog Neuropsychopharmacol Biol Psychiatry 2019; 89:245-253. [PMID: 30261217 DOI: 10.1016/j.pnpbp.2018.09.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 09/10/2018] [Accepted: 09/22/2018] [Indexed: 02/07/2023]
Abstract
Autism is a neurodevelopmental disorder that affects social cognitive abilities resulting in communication or sensory deficits, and stereotyped behaviors in millions of people worldwide. Oxidant-antioxidant imbalance contributes significantly to the neurobehavioral dysregulations and severity of symptoms in patients with autism, however it has not been explored earlier whether it affects autism-like behavior directly. Therefore, we investigated oxidant-antioxidant balance in peripheral immune cells (neutrophils and CD3+ T cells) and cerebellum of BTBR T + tf/J (BTBR) mice which show autism-like behavior and the social C57BL/6 J (C57) mice. Further, we utilized buthionine sulfoximine (BSO), a glutathione depleting agent to assess the impact of oxidant-antioxidant dysregulation on autism-like behavior. Our study shows that BTBR mice have increased lipid/protein oxidation products in cerebellum and neutrophils/CD3+ T cells along with increased NADPH oxidase (NOX2) and inducible nitric oxide synthase (iNOS) expression. This was concurrent with lower levels of glutathione and enzymatic antioxidants such as superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the cerebellum and peripheral immune cells. BSO administration led to further lowering of glutathione with a concurrent upregulation of iNOS, and NOX2 in cerebellum and peripheral immune cells. However, there was deficiency of an adaptive antioxidant response which was associated with exaggerated repetitive behaviors in BTBR mice. On the other hand, C57 mice also had increased oxidative stress after BSO treatment, however there was an enzymatic antioxidant response both in cerebellum and periphery. Overall, this study suggests that BTBR mice have increased oxidative stress with a deficient enzymatic antioxidant response that is associated with autism-like repetitive behaviors.
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Affiliation(s)
- Ahmed Nadeem
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.
| | - Sheikh F Ahmad
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Naif O Al-Harbi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Sabry M Attia
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Musaad A Alshammari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Khalid S Alzahrani
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Saleh A Bakheet
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
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Bjørklund G, Skalny AV, Rahman MM, Dadar M, Yassa HA, Aaseth J, Chirumbolo S, Skalnaya MG, Tinkov AA. Toxic metal(loid)-based pollutants and their possible role in autism spectrum disorder. ENVIRONMENTAL RESEARCH 2018; 166:234-250. [PMID: 29902778 DOI: 10.1016/j.envres.2018.05.020] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 05/18/2018] [Accepted: 05/18/2018] [Indexed: 06/08/2023]
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social interaction, verbal and non-verbal communication, and stereotypic behaviors. Many studies support a significant relationship between many different environmental factors in ASD etiology. These factors include increased daily exposure to various toxic metal-based environmental pollutants, which represent a cause for concern in public health. This article reviews the most relevant toxic metals, commonly found, environmental pollutants, i.e., lead (Pb), mercury (Hg), aluminum (Al), and the metalloid arsenic (As). Additionally, it discusses how pollutants can be a possible pathogenetic cause of ASD through various mechanisms including neuroinflammation in different regions of the brain, fundamentally occurring through elevation of the proinflammatory profile of cytokines and aberrant expression of nuclear factor kappa B (NF-κB). Due to the worldwide increase in toxic environmental pollution, studies on the role of pollutants in neurodevelopmental disorders, including direct effects on the developing brain and the subjects' genetic susceptibility and polymorphism, are of utmost importance to achieve the best therapeutic approach and preventive strategies.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Mo i Rana, Norway.
| | - Anatoly V Skalny
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia; Yaroslavl State University, Yaroslavl, Russia; All-Russian Research Institute of Medicinal and Aromatic Plants, Moscow, Russia
| | - Md Mostafizur Rahman
- Department of Environmental Sciences, Jahangirnagar University, Dhaka, Bangladesh; Graduate School of Environmental Science, Hokkaido University, Japan
| | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Heba A Yassa
- Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Jan Aaseth
- Faculty of Health and Social Sciences, Inland Norway University of Applied Sciences, Elverum, Norway; Department of Research, Innlandet Hospital Trust, Brumunddal, Norway
| | - Salvatore Chirumbolo
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
| | | | - Alexey A Tinkov
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia; Yaroslavl State University, Yaroslavl, Russia
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El-Ansary A, Cannell JJ, Bjørklund G, Bhat RS, Al Dbass AM, Alfawaz HA, Chirumbolo S, Al-Ayadhi L. In the search for reliable biomarkers for the early diagnosis of autism spectrum disorder: the role of vitamin D. Metab Brain Dis 2018; 33:917-931. [PMID: 29497932 DOI: 10.1007/s11011-018-0199-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 02/02/2018] [Indexed: 12/13/2022]
Abstract
Autism spectrum disorder (ASD) affects about 1% of the world's population. Vitamin D is thought to be essential for normal brain development and modulation of the immune system. Worldwide about 1 billion people are affected by vitamin D deficiency. High-sensitivity C-reactive protein (hs-CRP), cytochrome P450 2E1 (CYP2E1) and 8-hydroxy-2'-deoxyguanosine (8-OH-dG) are biomarkers related to inflammation and oxidative stress. In the present study, these biomarkers were together with serum 25-hydroxyvitamin D (25(OH)D3) analyzed in 28 (mean age seven years) Saudi male patients with ASD. The study was conducted to determine if there is any relationship between vitamin D levels, the tested biomarkers and the presence and severity of ASD. The hope was to identify if these biomarkers may be useful for early ASD diagnosis. The Childhood Autism Rating Scale (CARS) and the Social Responsiveness Scale (SRS) were used to measure autism severity. The results of the ASD children were compared with 27 age and gender-matched neurotypical controls. The data indicated that Saudi patients with ASD have significantly lower plasma levels of 25(OH)D3 than neurotypical controls (38 ng/ml compared to 56 ng/ml, respectively; [P = 0.001]). Surprisingly, the levels of CYP2E1 were lower in the children with ASD than the neurotypical controls (0.48 ± 0.08 vs. 69 ± 0.07 ng/ml, respectively; P = 0.001). The ASD children also had significantly higher levels of hs-CRP (0.79 ± 0.09 vs. 0.59 ± 0.09 ng/ml, respectively; P = 0.001) and 8-OH-dG (8.17 ± 1.04 vs. 4.13 ± 1.01 ng/ml, respectively; P = 0.001, compared to neurotypical age and gender-matched controls. The values for hs-CRP and 8-OH-dG did not correlate [P < 0.001] with autism severity. There was found a relationship between autism severity on the CARS scale and the levels of 25(OH)D3 and CYP1B1. But this was not found for SRS. All four biomarkers seemed to have good sensitivity and specificity, but the sample size of the present study was too small to determine clinical usefulness. The findings also indicate that inadequate levels of vitamin D play a role in the etiology and severity of autism. Furthermore, the results of the present study suggest the possibility of using 25(OH)D3, CYP1B1, hs-CRP and 8-OH-dG, preferably in combination, as biomarkers for the early diagnosis of ASD. However, further research is needed to evaluate this hypothesis.
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Affiliation(s)
- Afaf El-Ansary
- Central Laboratory, Female Centre for Scientific and Medical Studies, King Saud University, Riyadh, Saudi Arabia
- Medicinal Chemistry Department, National Research Centre, Dokki, Cairo, Egypt
- Autism Research and Treatment Center, Riyadh, Saudi Arabia
- Shaik AL-Amodi Autism Research Chair, King Saud University, Riyadh, Saudi Arabia
| | | | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Toften 24, 8610, Mo i Rana, Norway.
| | - Ramesa Shafi Bhat
- Biochemistry Department, Science College, King Saud University, Riyadh, Saudi Arabia
| | - Abeer M Al Dbass
- Biochemistry Department, Science College, King Saud University, Riyadh, Saudi Arabia
| | - Hanan A Alfawaz
- Department of Food Science and Human Nutrition, King Saud University, Riyadh, Saudi Arabia
| | - Salvatore Chirumbolo
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
| | - Laila Al-Ayadhi
- Autism Research and Treatment Center, Riyadh, Saudi Arabia
- Shaik AL-Amodi Autism Research Chair, King Saud University, Riyadh, Saudi Arabia
- Department of Physiology, Faculty of Medicine, King Saud University, Riyadh, Saudi Arabia
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23
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Oliveira CS, Nogara PA, Ardisson-Araújo DMP, Aschner M, Rocha JBT, Dórea JG. Neurodevelopmental Effects of Mercury. ADVANCES IN NEUROTOXICOLOGY 2018; 2:27-86. [PMID: 32346667 PMCID: PMC7188190 DOI: 10.1016/bs.ant.2018.03.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The toxicology of mercury (Hg) is of concern since this metal is ubiquitously distributed in the environment, and living organisms are routinely exposed to Hg at low to high levels. The toxic effects of Hg are well studied and it is known that they may differ depending on the Hg chemical species. In this chapter, we emphasize the neurotoxic effects of Hg during brain development. The immature brain is more susceptible to Hg exposure, since all the Hg chemical forms, not only the organic ones, can harm it. The possible consequences of Hg exposure during the early stages of development, the additive effects with other co-occurring neurotoxicants, and the known mechanisms of action and targets will be addressed in this chapter.
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Affiliation(s)
- Cláudia S Oliveira
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Pablo A Nogara
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Daniel M P Ardisson-Araújo
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Laboratório de Virologia de Insetos, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, NY, USA
| | - João B T Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - José G Dórea
- Professor Emeritus, Faculdade de Ciências da Saúde, Universidade de Brasília, Brasília, DF, Brazil
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Altamimi M. Could Autism Be Associated With Nutritional Status in the Palestinian population? The Outcomes of the Palestinian Micronutrient Survey. Nutr Metab Insights 2018; 11:1178638818773078. [PMID: 29773950 PMCID: PMC5952272 DOI: 10.1177/1178638818773078] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/04/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Autism spectrum disorder is a neurodevelopmental disorder. It is believed that the cause of autism is multifactorial, where genetic predispositions interact with environmental factors. In this context, micronutrients play a crucial role. OBJECTIVE To present evidence on current micronutrient status in Palestine and highlight its possible role in increasing problems of neurodevelopment disorders in general and autism in particular. METHOD Analytical review of results. RESULTS AND CONCLUSIONS The Palestinian Micronutrient Survey was conducted to assess micronutrient status in most vulnerable groups and also micronutrient deficiencies. The data from Palestinian population showed severe anaemia due to iron, Zn, B12, and folic acid deficiencies. One in every 3 Palestinian pregnant women is anaemic. Moreover, 78.2% and 87.1% of lactating mothers from the West Bank and Gaza Strip are Zn deficient. For children from 6 to 59 months old, 1 in every 4 boys and 1 in every 5 girls are considered anaemic. Similar trend was found with respect to vitamins E, D, A, and folic acid. We reviewed the literature that linked micronutrient deficiencies to neurodevelopmental disorders and expected the number of neurodevelopmental disorder cases, including autism, to increase.
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Affiliation(s)
- Mohammad Altamimi
- Department of Nutrition and Food technology, An-Najah National University, Nablus, Palestine
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25
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Waye MMY, Cheng HY. Genetics and epigenetics of autism: A Review. Psychiatry Clin Neurosci 2018; 72:228-244. [PMID: 28941239 DOI: 10.1111/pcn.12606] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 09/13/2017] [Accepted: 09/15/2017] [Indexed: 01/01/2023]
Abstract
Autism is a developmental disorder that starts before age 3 years, and children with autism have impairment in both social interaction and communication, and have restricted, repetitive, and stereotyped patterns of behavior, interests, and activities. There is a strong heritable component of autism and autism spectrum disorder (ASD) as studies have shown that parents who have a child with ASD have a 2-18% chance of having a second child with ASD. The prevalence of autism and ASD have been increasing during the last 3 decades and much research has been carried out to understand the etiology, so as to develop novel preventive and treatment strategies. This review aims at summarizing the latest research studies related to autism and ASD, focusing not only on the genetics but also some epigenetic findings of autism/ASD. Some promising areas of research using transgenic/knockout animals and some ideas related to potential novel treatment and prevention strategies will be discussed.
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Affiliation(s)
- Mary M Y Waye
- The Nethersole School of Nursing, The Croucher Laboratory for Human Genomics, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Ho Yu Cheng
- The Nethersole School of Nursing, The Croucher Laboratory for Human Genomics, The Chinese University of Hong Kong, Hong Kong SAR, China
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26
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Skalny AV, Simashkova NV, Skalnaya MG, Klyushnik TP, Chernova LN, Tinkov AA. Mercury and autism spectrum disorders. Zh Nevrol Psikhiatr Im S S Korsakova 2018; 118:75-79. [DOI: 10.17116/jnevro20181185275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Kern JK, Geier DA, Deth RC, Sykes LK, Hooker BS, Love JM, Bjørklund G, Chaigneau CG, Haley BE, Geier MR. RETRACTED ARTICLE: Systematic Assessment of Research on Autism Spectrum Disorder and Mercury Reveals Conflicts of Interest and the Need for Transparency in Autism Research. SCIENCE AND ENGINEERING ETHICS 2017; 23:1689-1690. [PMID: 26507205 PMCID: PMC5705728 DOI: 10.1007/s11948-015-9713-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 10/19/2015] [Indexed: 06/05/2023]
Affiliation(s)
- Janet K. Kern
- Institute of Chronic Illnesses, Inc., 14 Redgate Court, Silver Spring, MD 20905 USA
| | - David A. Geier
- Institute of Chronic Illnesses, Inc., 14 Redgate Court, Silver Spring, MD 20905 USA
| | | | | | | | | | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Mo i Rana, Norway
| | | | | | - Mark R. Geier
- Institute of Chronic Illnesses, Inc., 14 Redgate Court, Silver Spring, MD 20905 USA
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28
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Kern JK, Geier DA, Deth RC, Sykes LK, Hooker BS, Love JM, Bjørklund G, Chaigneau CG, Haley BE, Geier MR. Systematic Assessment of Research on Autism Spectrum Disorder (ASD) and Mercury Reveals Conflicts of Interest and the Need for Transparency in Autism Research. SCIENCE AND ENGINEERING ETHICS 2017; 23:1691-1718. [PMID: 29119411 PMCID: PMC5705731 DOI: 10.1007/s11948-017-9983-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Historically, entities with a vested interest in a product that critics have suggested is harmful have consistently used research to back their claims that the product is safe. Prominent examples are: tobacco, lead, bisphenol A, and atrazine. Research literature indicates that about 80-90% of studies with industry affiliation found no harm from the product, while only about 10-20% of studies without industry affiliation found no harm. In parallel to other historical debates, recent studies examining a possible relationship between mercury (Hg) exposure and autism spectrum disorder (ASD) show a similar dichotomy. Studies sponsored and supported by industry or entities with an apparent conflict of interest have most often shown no evidence of harm or no "consistent" evidence of harm, while studies without such affiliations report positive evidence of a Hg/autism association. The potentially causal relationship between Hg exposure and ASD differs from other toxic products since there is a broad coalition of entities for whom a conflict of interest arises. These include influential governmental public health entities, the pharmaceutical industry, and even the coal burning industry. This review includes a systematic literature search of original studies on the potential relationship between Hg and ASD from 1999 to August 2015, finding that of the studies with public health and/or industry affiliation, 86% reported no relationship between Hg and ASD. However, among studies without public health and/or industry affiliation, only 21% find no relationship between Hg and ASD. The discrepancy in these results suggests a bias indicative of a conflict of interest.
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Affiliation(s)
- Janet K. Kern
- Institute of Chronic Illnesses, Inc, 14 Redgate Court, Silver Spring, MD 20905 USA
| | - David A. Geier
- Institute of Chronic Illnesses, Inc, 14 Redgate Court, Silver Spring, MD 20905 USA
| | | | | | | | | | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Mo i Rana, Norway
| | | | | | - Mark R. Geier
- Institute of Chronic Illnesses, Inc, 14 Redgate Court, Silver Spring, MD 20905 USA
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Jafari T, Rostampour N, Fallah AA, Hesami A. The association between mercury levels and autism spectrum disorders: A systematic review and meta-analysis. J Trace Elem Med Biol 2017; 44:289-297. [PMID: 28965590 DOI: 10.1016/j.jtemb.2017.09.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 08/30/2017] [Accepted: 09/01/2017] [Indexed: 12/15/2022]
Abstract
BACKGROUND & AIMS The relationship between mercury and autism spectrum disorders (ASD) has always been a topic of controversy among researchers. This study aimed to assess the relationship between ASD and mercury levels in hair, urine, blood, red blood cells (RBC), and brain through a meta-analysis. METHODS A systematic search was performed in several databases including PubMed, ISI Web of Science, Cochrane register of controlled trials, Google Scholar, Scopus, and MagIran until June 2017. Case-control studies evaluating concentration of total mercury in different tissues of ASD patients and comparing them to the healthy subjects (control group) were identified. Necessary data were extracted and random effects model was used to calculate overall effect and its 95% corresponding confidence interval (CI) from the effect sizes. RESULTS A total of 44 studies were identified that met the necessary criteria for meta-analysis. The mercury level in whole blood (Hedges=0.43, 95% CI: 0.12, 0.74, P=0.007), RBC (Hedges=1.61, 95% CI: 0.83, 2.38, P<0.001), and brain (0.61ng/g, 95% CI, 0.02, 1.19, P=0.043) was significantly higher in ASD patients than healthy subjects, whereas mercury level in hair (-0.14mg/g, 95% CI: -0.28, -0.01, P=0.039) was significantly lower in ASD patients than healthy subjects. The mercury level in urine was not significantly different between ASD patients and healthy subjects (0.51mg/g creatinine, 95% CI: -0.14, 1.16, P=0.121). CONCLUSIONS Results of the current meta-analysis revealed that mercury is an important causal factor in the etiology of ASD. It seems that the detoxification and excretory mechanisms are impaired in ASD patients which lead to accumulation of mercury in the body. Future additional studies on mercury levels in different tissues of ASD patients should be undertaken.
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Affiliation(s)
- Tina Jafari
- Clinical Biochemistry Research Center, Shahrekord University of Medical Sciences, Sharhekord, Iran; Department of Biochemistry and Nutrition, Faculty of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran.
| | - Noushin Rostampour
- Department of Pediatrics, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Aziz A Fallah
- Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord 34141, Iran
| | - Afshin Hesami
- Clinical Biochemistry Research Center, Shahrekord University of Medical Sciences, Sharhekord, Iran
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Saghazadeh A, Rezaei N. Systematic review and meta-analysis links autism and toxic metals and highlights the impact of country development status: Higher blood and erythrocyte levels for mercury and lead, and higher hair antimony, cadmium, lead, and mercury. Prog Neuropsychopharmacol Biol Psychiatry 2017; 79:340-368. [PMID: 28716727 DOI: 10.1016/j.pnpbp.2017.07.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 07/12/2017] [Accepted: 07/13/2017] [Indexed: 12/15/2022]
Abstract
BACKGROUND Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder that affects cognitive and higher cognitive functions. Increasing prevalence of ASD and high rates of related comorbidities has caused serious health loss and placed an onerous burden on the supporting families, caregivers, and health care services. Heavy metals are among environmental factors that may contribute to ASD. However, due to inconsistencies across studies, it is still hard to explain the association between ASD and toxic metals. Therefore the objective of this study was to investigate the difference in heavy metal measures between patients with ASD and control subjects. METHODS We included observational studies that measured levels of toxic metals (antimony, arsenic, cadmium, lead, manganese, mercury, nickel, silver, and thallium) in different specimens (whole blood, plasma, serum, red cells, hair and urine) for patients with ASD and for controls. The main electronic medical database (PubMed and Scopus) were searched from inception through October 2016. RESULTS 52 studies were eligible to be included in the present systematic review, of which 48 studies were included in the meta-analyses. The hair concentrations of antimony (standardized mean difference (SMD)=0.24; 95% confidence interval (CI): 0.03 to 0.45) and lead (SMD=0.60; 95% confidence interval (CI): 0.17 to 1.03) in ASD patients were significantly higher than those of control subjects. ASD patients had higher erythrocyte levels of lead (SMD=1.55, CI: 0.2 to 2.89) and mercury (SMD=1.56, CI: 0.42 to 2.70). There were significantly higher blood lead levels in ASD patients (SMD=0.43, CI: 0.02 to 0.85). Sensitivity analyses showed that ASD patients in developed but not in developing countries have lower hair concentrations of cadmium (SMD=-0.29, CI: -0.46 to -0.12). Also, such analyses indicated that ASD patients in developing but not in developed lands have higher hair concentrations of lead (SMD=1.58, CI: 0.80 to 2.36) and mercury (SMD=0.77, CI: 0.31 to 1.23). These findings were confirmed by meta-regression analyses indicating that development status of countries significantly influences the overall effect size of mean difference for hair arsenic, cadmium, lead, and mercury between patients with ASD and controls. CONCLUSION The findings help highlighting the role of toxic metals as environmental factors in the etiology of ASD, especially in developing lands. While there are environmental factors other than toxic metals that greatly contribute to the etiology of ASD in developed lands. It would be, thus, expected that classification of ASD includes etiological entities of ASD on the basis of implication of industrial pollutants (developed vs. developing ASD).
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Affiliation(s)
- Amene Saghazadeh
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; MetaCognition Interest Group (MCIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Nima Rezaei
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Systematic Review and Meta-analysis Expert Group (SRMEG), Universal Scientific Education and Research Network (USERN), Boston, MA, USA.
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31
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El-Ansary A, Bjørklund G, Chirumbolo S, Alnakhli OM. Predictive value of selected biomarkers related to metabolism and oxidative stress in children with autism spectrum disorder. Metab Brain Dis 2017; 32:1209-1221. [PMID: 28497358 DOI: 10.1007/s11011-017-0029-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 05/01/2017] [Indexed: 10/19/2022]
Abstract
Autism spectrum disorder (ASD) as a neurodevelopmental disorder is characterized by impairments in social interaction, communication, and restricted, repetitive behavior. Several and reproducible studies have suggested that oxidative stress may represent one of the primary etiological mechanism of ASD that can be targeted for therapeutic intervention. In the present study, multiple regression and combined receiver operating characteristic (ROC) analysis were used to search for a relationship between impaired energy and oxidative metabolic pathways in the etiology of ASD and to find the linear combination that maximizes the partial area under a ROC curve for a pre-identified set of markers related to energy metabolism and oxidative stress. Thirty children with ASD and 30 age and gender matched controls were enrolled in the study. Using either spectrophotometric or ELISA-colorimetric assay, levels of lipid peroxides, vitamin E, vitamin C, glutathione (GSH)/glutathione disulfide (GSSG) together with the enzymatic activity of catalase, plasma glutathione peroxidase (GPx), and blood superoxide dismutase (SOD), were measured in peripheral blood samples, as biomarkers related to oxidative stress. Creatine kinase, ectonucleotidases (ADPase and ATPase) Na+/K+ (ATPase), lactate, inorganic phosphate, and levels of adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP) together with adenylate energy charge, were also measured as markers of impaired energy metabolism. Statistical analysis using ROC curves, multiple and logistic regression were performed. A remarkable increase in the area under the curve for most of the combined markers, representing both energy impaired metabolism or oxidative stress, was observed by using combined ROC analyses. Moreover, higher specificity and sensitivity of the combined markers were also reported. The present study indicated that the measurement of the predictive value of selected biomarkers related to energy metabolism and oxidative stress in children with ASD using ROC analysis should lead to the better identification of the etiological mechanism of ASD associated with metabolism and diet. Agents with activity against the impaired metabolic pathway associated with ASD including the metabolic defects and involved enzymes hold a promise as a novel therapy for ASD.
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Affiliation(s)
- Afaf El-Ansary
- Central Laboratory, Female Center for Medical Studies and Scientific Section, King Saud University, Riyadh, Saudi Arabia.
| | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Mo i Rana, Norway
| | - Salvatore Chirumbolo
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
| | - Osima M Alnakhli
- Central Laboratory, Female Center for Medical Studies and Scientific Section, King Saud University, Riyadh, Saudi Arabia
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Comparison of Protein N-Homocysteinylation in Rat Plasma under Elevated Homocysteine Using a Specific Chemical Labeling Method. Molecules 2016; 21:molecules21091195. [PMID: 27617989 PMCID: PMC5292613 DOI: 10.3390/molecules21091195] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 09/02/2016] [Accepted: 09/05/2016] [Indexed: 11/30/2022] Open
Abstract
Elevated blood concentrations of homocysteine have been well established as a risk factor for cardiovascular diseases and neuropsychiatric diseases, yet the etiologic relationship of homocysteine to these disorders remains poorly understood. Protein N-homocysteinylation has been hypothesized as a contributing factor; however, it has not been examined globally owing to the lack of suitable detection methods. We recently developed a selective chemical method to label N-homocysteinylated proteins with a biotin-aldehyde tag followed by Western blotting analysis, which was further optimized in this study. We then investigated the variation of protein N-homocysteinylation in plasma from rats on a vitamin B12 deficient diet. Elevated “total homocysteine” concentrations were determined in rats with a vitamin B12 deficient diet. Correspondingly, overall levels of plasma protein N-homocysteinylation displayed an increased trend, and furthermore, more pronounced and statistically significant changes (e.g., 1.8-fold, p-value: 0.03) were observed for some individual protein bands. Our results suggest that, as expected, a general metabolic correlation exists between “total homocysteine” and N-homocysteinylation, although other factors are involved in homocysteine/homocysteine thiolactone metabolism, such as the transsulfuration of homocysteine by cystathionine β-synthase or the hydrolysis of homocysteine thiolactone by paraoxonase 1 (PON1), may play more significant or direct roles in determining the level of N-homocysteinylation.
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Kern JK, Geier DA, Sykes LK, Haley BE, Geier MR. The relationship between mercury and autism: A comprehensive review and discussion. J Trace Elem Med Biol 2016; 37:8-24. [PMID: 27473827 DOI: 10.1016/j.jtemb.2016.06.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 05/17/2016] [Accepted: 06/01/2016] [Indexed: 12/28/2022]
Abstract
The brain pathology in autism spectrum disorders (ASD) indicates marked and ongoing inflammatory reactivity with concomitant neuronal damage. These findings are suggestive of neuronal insult as a result of external factors, rather than some type of developmental mishap. Various xenobiotics have been suggested as possible causes of this pathology. In a recent review, the top ten environmental compounds suspected of causing autism and learning disabilities were listed and they included: lead, methyl-mercury, polychorinated biphenyls, organophosphate pesticides, organochlorine pesticides, endocrine disruptors, automotive exhaust, polycyclic aromatic hydrocarbons, polybrominated diphenyl ethers, and perfluorinated compounds. This current review, however, will focus specifically on mercury exposure and ASD by conducting a comprehensive literature search of original studies in humans that examine the potential relationship between mercury and ASD, categorizing, summarizing, and discussing the published research that addresses this topic. This review found 91 studies that examine the potential relationship between mercury and ASD from 1999 to February 2016. Of these studies, the vast majority (74%) suggest that mercury is a risk factor for ASD, revealing both direct and indirect effects. The preponderance of the evidence indicates that mercury exposure is causal and/or contributory in ASD.
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Affiliation(s)
- Janet K Kern
- Institute of Chronic Illnesses, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA; Council for Nutritional and Environmental Medicine, Mo i Rana, Norway; CoMeD, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA.
| | - David A Geier
- Institute of Chronic Illnesses, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA; CoMeD, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA
| | - Lisa K Sykes
- CoMeD, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA
| | - Boyd E Haley
- University of Kentucky, 410 Administration Drive, Lexington, KY, 40506 USA
| | - Mark R Geier
- Institute of Chronic Illnesses, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA; CoMeD, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA
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Mostafa GA, Bjørklund G, Urbina MA, Al-Ayadhi LY. The levels of blood mercury and inflammatory-related neuropeptides in the serum are correlated in children with autism spectrum disorder. Metab Brain Dis 2016; 31:593-9. [PMID: 26738726 DOI: 10.1007/s11011-015-9784-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 12/22/2015] [Indexed: 12/15/2022]
Abstract
Tachykinins (substance P, neurokinin A, and neurokinin B) are pro-inflammatory neuropeptides that may play an important role in some autoimmune neuroinflammatory diseases, including autism spectrum disorder (ASD). Mercury (Hg) is a neurotoxicant, and potentially one of the main environmental triggers for ASD as it induces neuroinflammation with a subsequent release of neuropeptides. This is the first study to explore the potentially causal relationship between levels of serum neurokinin A and blood mercury (BHg) in children with ASD. Levels of serum neurokinin A and BHg were measured in 84 children with ASD, aged between 3 and 10 years, and 84 healthy-matched children. There was a positive linear relationship between the Childhood Autism Rating Scale (CARS) and both serum neurokinin A and BHg. ASD children had significantly higher levels of serum neurokinin A than healthy controls (P < 0.001). Increased levels of serum neurokinin A and BHg were respectively found in 54.8 % and 42.9 % of the two groups. There was significant and positive linear relationship between levels of serum neurokinin A and BHg in children with moderate and severe ASD, but not in healthy control children. It was found that 78.3 % of the ASD patients with increased serum levels of neurokinin A had elevated BHg levels (P < 0.001). Neuroinflammation, with increased levels of neurokinin A, is seen in some children with ASD, and may be caused by elevated BHg levels. Further research is recommended to determine the pathogenic role of increased levels of serum neurokinin A and BHg in ASD. The therapeutic role of tachykinin receptor antagonists, a potential new class of anti-inflammatory medications, and Hg chelators, should also be studied in ASD.
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Affiliation(s)
- Gehan Ahmed Mostafa
- Department of Pediatrics, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
- Autism Research and Treatment Center, AL-Amodi Autism Research Chair, Department of Physiology, Faculty of Medicine, King Saud University, Riyadh, Saudi Arabia.
| | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Toften 24, 8610, Mo i Rana, Norway
| | - Mauricio A Urbina
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
- Departamento de Zoología, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Laila Yousef Al-Ayadhi
- Autism Research and Treatment Center, AL-Amodi Autism Research Chair, Department of Physiology, Faculty of Medicine, King Saud University, Riyadh, Saudi Arabia
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Mischley LK, Conley KE, Shankland EG, Kavanagh TJ, Rosenfeld ME, Duda JE, White CC, Wilbur TK, De La Torre PU, Padowski JM. Central nervous system uptake of intranasal glutathione in Parkinson's disease. NPJ Parkinsons Dis 2016; 2:16002. [PMID: 28725693 PMCID: PMC5516583 DOI: 10.1038/npjparkd.2016.2] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 12/03/2015] [Accepted: 12/10/2015] [Indexed: 11/16/2022] Open
Abstract
Glutathione (GSH) is depleted early in the course of Parkinson's disease (PD), and deficiency has been shown to perpetuate oxidative stress, mitochondrial dysfunction, impaired autophagy, and cell death. GSH repletion has been proposed as a therapeutic intervention. The objective of this study was to evaluate whether intranasally administered reduced GSH, (in)GSH, is capable of augmenting central nervous system GSH concentrations, as determined by magnetic resonance spectroscopy in 15 participants with mid-stage PD. After baseline GSH measurement, 200 mg (in)GSH was self-administered inside the scanner without repositioning, then serial GSH levels were obtained over ~1 h. Statistical significance was determined by one-way repeated measures analysis of variance. Overall, (in)GSH increased brain GSH relative to baseline (P<0.001). There was no increase in GSH 8 min after administration, although it was significantly higher than baseline at all of the remaining time points (P<0.01). This study is the first to demonstrate that intranasal administration of GSH elevates brain GSH levels. This increase persists at least 1 h in subjects with PD. Further dose-response and steady-state administration studies will be required to optimize the dosing schedule for future trials to evaluate therapeutic efficacy.
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Affiliation(s)
- Laurie K Mischley
- Department of Radiology, University of Washington (UW), Seattle, WA, USA
- Graduate Program in Nutritional Sciences, School of Public Health, University of Washington, Seattle, WA, USA
- School of Naturopathic Medicine, Bastyr University Research Institute, Kenmore, WA, USA
| | - Kevin E Conley
- Department of Radiology, University of Washington (UW), Seattle, WA, USA
| | - Eric G Shankland
- Department of Radiology, University of Washington (UW), Seattle, WA, USA
| | - Terrance J Kavanagh
- Department of Environmental & Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| | - Michael E Rosenfeld
- Graduate Program in Nutritional Sciences, School of Public Health, University of Washington, Seattle, WA, USA
- Department of Environmental & Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| | - John E Duda
- Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Collin C White
- Department of Environmental & Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| | - Timothy K Wilbur
- Department of Radiology, University of Washington (UW), Seattle, WA, USA
| | - Prysilla U De La Torre
- Department of Radiology, University of Washington (UW), Seattle, WA, USA
- School of Naturopathic Medicine, Bastyr University Research Institute, Kenmore, WA, USA
| | - Jeannie M Padowski
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA
- Department of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, USA
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Alternatively Spliced Methionine Synthase in SH-SY5Y Neuroblastoma Cells: Cobalamin and GSH Dependence and Inhibitory Effects of Neurotoxic Metals and Thimerosal. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:6143753. [PMID: 26989453 PMCID: PMC4775819 DOI: 10.1155/2016/6143753] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 12/28/2015] [Accepted: 01/10/2016] [Indexed: 12/05/2022]
Abstract
The folate and cobalamin (Cbl-) dependent enzyme methionine synthase (MS) is highly sensitive to oxidation and its activity affects all methylation reactions. Recent studies have revealed alternative splicing of MS mRNA in human brain and patient-derived fibroblasts. Here we show that MS mRNA in SH-SY5Y human neuroblastoma cells is alternatively spliced, resulting in three primary protein species, thus providing a useful model to examine cofactor dependence of these variant enzymes. MS activity was dependent upon methylcobalamin (MeCbl) or the combination of hydroxocobalamin (OHCbl) and S-adenosylmethionine (SAM). OHCbl-based activity was eliminated by depletion of the antioxidant glutathione (GSH) but could be rescued by provision of either glutathionylcobalamin (GSCbl) or MeCbl. Pretreatment of cells with lead, arsenic, aluminum, mercury, or the ethylmercury-containing preservative thimerosal lowered GSH levels and inhibited MS activity in association with decreased uptake of cysteine, which is rate-limiting for GSH synthesis. Thimerosal treatment decreased cellular levels of GSCbl and MeCbl. These findings indicate that the alternatively spliced form of MS expressed in SH-SY5Y human neuronal cells is sensitive to inhibition by thimerosal and neurotoxic metals, and lower GSH levels contribute to their inhibitory action.
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Abstract
PURPOSE OF REVIEW Glutathione (GSH) is a major endogenous antioxidant. Several studies have implicated GSH redox imbalance in brain disorders. Here, we summarize current evidence on how GSH depletion and GSH-related enzyme deficit are involved in the pathology of brain disorders such as autism, schizophrenia, bipolar disorder, Alzheimer's disease, and Parkinson's disease. RECENT FINDINGS Many studies with animal models of various brain disorders and/or with clinical samples from humans with neurodegenerative and neuropsychiatric disorders have demonstrated altered levels of GSH and oxidized glutathione (GSSG), decreased ratio of GSH/GSSG, and/or impaired expressions or activities of GSH-related enzymes in the blood or brain of these individuals. GSH depletion can lead to abnormalities in methylation metabolism and mitochondrial function. A few studies showed that a GSH deficit occurs prior to neuropathological abnormalities in these diseases. The potential therapeutic agents for brain disorders include N-acetylcysteine, liposomes encapsulated with GSH, and whey protein supplement, which can increase the GSH levels in the brain and alleviate oxidative stress-associated damage and may improve the behavior of individuals with brain diseases. SUMMARY GSH plays an important role during the onset and progression of neuropsychiatric and neurodegenerative diseases. GSH redox imbalance may be a primary cause of these brain disorders and may be used as a biomarker for diagnosis of these diseases. N-acetylcysteine and other agents that can increase the concentration of GSH in the brain are promising approaches for the treatment of these brain disorders.
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Affiliation(s)
- Feng Gu
- NYS Institute for Basic Research in Developmental Disabilities, Staten Island, New York, USA
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