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Millevert C, Vidas-Guscic N, Vanherp L, Jonckers E, Verhoye M, Staelens S, Bertoglio D, Weckhuysen S. Resting-State Functional MRI and PET Imaging as Noninvasive Tools to Study (Ab)Normal Neurodevelopment in Humans and Rodents. J Neurosci 2023; 43:8275-8293. [PMID: 38073598 PMCID: PMC10711730 DOI: 10.1523/jneurosci.1043-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 06/09/2023] [Accepted: 09/13/2023] [Indexed: 12/18/2023] Open
Abstract
Neurodevelopmental disorders (NDDs) are a group of complex neurologic and psychiatric disorders. Functional and molecular imaging techniques, such as resting-state functional magnetic resonance imaging (rs-fMRI) and positron emission tomography (PET), can be used to measure network activity noninvasively and longitudinally during maturation in both humans and rodent models. Here, we review the current knowledge on rs-fMRI and PET biomarkers in the study of normal and abnormal neurodevelopment, including intellectual disability (ID; with/without epilepsy), autism spectrum disorder (ASD), and attention deficit hyperactivity disorder (ADHD), in humans and rodent models from birth until adulthood, and evaluate the cross-species translational value of the imaging biomarkers. To date, only a few isolated studies have used rs-fMRI or PET to study (abnormal) neurodevelopment in rodents during infancy, the critical period of neurodevelopment. Further work to explore the feasibility of performing functional imaging studies in infant rodent models is essential, as rs-fMRI and PET imaging in transgenic rodent models of NDDs are powerful techniques for studying disease pathogenesis, developing noninvasive preclinical imaging biomarkers of neurodevelopmental dysfunction, and evaluating treatment-response in disease-specific models.
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Affiliation(s)
- Charissa Millevert
- Applied & Translational Neurogenomics Group, Vlaams Instituut voor Biotechnology (VIB) Center for Molecular Neurology, VIB, Antwerp 2610, Belgium
- Department of Neurology, University Hospital of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Nicholas Vidas-Guscic
- Bio-Imaging Lab, University of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Liesbeth Vanherp
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Elisabeth Jonckers
- Bio-Imaging Lab, University of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Marleen Verhoye
- Bio-Imaging Lab, University of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Steven Staelens
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Daniele Bertoglio
- Bio-Imaging Lab, University of Antwerp, Antwerp 2610, Belgium
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Sarah Weckhuysen
- Applied & Translational Neurogenomics Group, Vlaams Instituut voor Biotechnology (VIB) Center for Molecular Neurology, VIB, Antwerp 2610, Belgium
- Department of Neurology, University Hospital of Antwerp, Antwerp 2610, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
- Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Antwerp 2610, Belgium
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Nisar S, Haris M. Neuroimaging genetics approaches to identify new biomarkers for the early diagnosis of autism spectrum disorder. Mol Psychiatry 2023; 28:4995-5008. [PMID: 37069342 DOI: 10.1038/s41380-023-02060-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 03/23/2023] [Accepted: 03/28/2023] [Indexed: 04/19/2023]
Abstract
Autism-spectrum disorders (ASDs) are developmental disabilities that manifest in early childhood and are characterized by qualitative abnormalities in social behaviors, communication skills, and restrictive or repetitive behaviors. To explore the neurobiological mechanisms in ASD, extensive research has been done to identify potential diagnostic biomarkers through a neuroimaging genetics approach. Neuroimaging genetics helps to identify ASD-risk genes that contribute to structural and functional variations in brain circuitry and validate biological changes by elucidating the mechanisms and pathways that confer genetic risk. Integrating artificial intelligence models with neuroimaging data lays the groundwork for accurate diagnosis and facilitates the identification of early diagnostic biomarkers for ASD. This review discusses the significance of neuroimaging genetics approaches to gaining a better understanding of the perturbed neurochemical system and molecular pathways in ASD and how these approaches can detect structural, functional, and metabolic changes and lead to the discovery of novel biomarkers for the early diagnosis of ASD.
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Affiliation(s)
- Sabah Nisar
- Laboratory of Molecular and Metabolic Imaging, Sidra Medicine, Doha, Qatar
- Department of Diagnostic Imaging, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Mohammad Haris
- Laboratory of Molecular and Metabolic Imaging, Sidra Medicine, Doha, Qatar.
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Laboratory Animal Research Center, Qatar University, Doha, Qatar.
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Béland-Millar A, Kirby A, Truong Y, Ouellette J, Yandiev S, Bouyakdan K, Pileggi C, Naz S, Yin M, Carrier M, Kotchetkov P, St-Pierre MK, Tremblay MÈ, Courchet J, Harper ME, Alquier T, Messier C, Shuhendler AJ, Lacoste B. 16p11.2 haploinsufficiency reduces mitochondrial biogenesis in brain endothelial cells and alters brain metabolism in adult mice. Cell Rep 2023; 42:112485. [PMID: 37149866 DOI: 10.1016/j.celrep.2023.112485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 02/20/2023] [Accepted: 04/22/2023] [Indexed: 05/09/2023] Open
Abstract
Neurovascular abnormalities in mouse models of 16p11.2 deletion autism syndrome are reminiscent of alterations reported in murine models of glucose transporter deficiency, including reduced brain angiogenesis and behavioral alterations. Yet, whether cerebrovascular alterations in 16p11.2df/+ mice affect brain metabolism is unknown. Here, we report that anesthetized 16p11.2df/+ mice display elevated brain glucose uptake, a phenomenon recapitulated in mice with endothelial-specific 16p11.2 haplodeficiency. Awake 16p11.2df/+ mice display attenuated relative fluctuations of extracellular brain glucose following systemic glucose administration. Targeted metabolomics on cerebral cortex extracts reveals enhanced metabolic responses to systemic glucose in 16p11.2df/+ mice that also display reduced mitochondria number in brain endothelial cells. This is not associated with changes in mitochondria fusion or fission proteins, but 16p11.2df/+ brain endothelial cells lack the splice variant NT-PGC-1α, suggesting defective mitochondrial biogenesis. We propose that altered brain metabolism in 16p11.2df/+ mice is compensatory to endothelial dysfunction, shedding light on previously unknown adaptative responses.
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Affiliation(s)
- Alexandria Béland-Millar
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada; School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | - Alexia Kirby
- Faculty of Science, Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Yen Truong
- Faculty of Science, Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Julie Ouellette
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada; Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Sozerko Yandiev
- University Lyon 1, CNRS, INSERM, Physiopathologie et Génétique du Neurone et du Muscle, UMR5261, U1315, Institut NeuroMyoGène, 69008 Lyon, France
| | - Khalil Bouyakdan
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Department of Medicine Université de Montréal, Montreal, QC, Canada
| | - Chantal Pileggi
- Faculty of Medicine, Department of Biochemistry Microbiology and Immunology, Ottawa, ON, Canada
| | - Shama Naz
- University of Ottawa Metabolomics Core Facility, Faculty of Medicine, Ottawa, ON, Canada
| | - Melissa Yin
- FUJIFILM VisualSonics, Inc, Toronto, ON, Canada
| | - Micaël Carrier
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Pavel Kotchetkov
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada; Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | | | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada; Neurology and Neurosurgery Department, McGill University, Montreal, QC, Canada; Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
| | - Julien Courchet
- University Lyon 1, CNRS, INSERM, Physiopathologie et Génétique du Neurone et du Muscle, UMR5261, U1315, Institut NeuroMyoGène, 69008 Lyon, France
| | - Mary-Ellen Harper
- Faculty of Medicine, Department of Biochemistry Microbiology and Immunology, Ottawa, ON, Canada
| | - Thierry Alquier
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Department of Medicine Université de Montréal, Montreal, QC, Canada
| | - Claude Messier
- School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | - Adam J Shuhendler
- Faculty of Science, Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON, Canada; University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada
| | - Baptiste Lacoste
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada; Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada; University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada.
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MeCP2 Is an Epigenetic Factor That Links DNA Methylation with Brain Metabolism. Int J Mol Sci 2023; 24:ijms24044218. [PMID: 36835623 PMCID: PMC9966807 DOI: 10.3390/ijms24044218] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/10/2023] [Accepted: 02/15/2023] [Indexed: 02/22/2023] Open
Abstract
DNA methylation, one of the most well-studied epigenetic modifications, is involved in a wide spectrum of biological processes. Epigenetic mechanisms control cellular morphology and function. Such regulatory mechanisms involve histone modifications, chromatin remodeling, DNA methylation, non-coding regulatory RNA molecules, and RNA modifications. One of the most well-studied epigenetic modifications is DNA methylation that plays key roles in development, health, and disease. Our brain is probably the most complex part of our body, with a high level of DNA methylation. A key protein that binds to different types of methylated DNA in the brain is the methyl-CpG binding protein 2 (MeCP2). MeCP2 acts in a dose-dependent manner and its abnormally high or low expression level, deregulation, and/or genetic mutations lead to neurodevelopmental disorders and aberrant brain function. Recently, some of MeCP2-associated neurodevelopmental disorders have emerged as neurometabolic disorders, suggesting a role for MeCP2 in brain metabolism. Of note, MECP2 loss-of-function mutation in Rett Syndrome is reported to cause impairment of glucose and cholesterol metabolism in human patients and/or mouse models of disease. The purpose of this review is to outline the metabolic abnormalities in MeCP2-associated neurodevelopmental disorders that currently have no available cure. We aim to provide an updated overview into the role of metabolic defects associated with MeCP2-mediated cellular function for consideration of future therapeutic strategies.
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Ezedinma U, Swierkowski P, Fjaagesund S. Outcomes from Individual Alpha Frequency Guided Repetitive Transcranial Magnetic Stimulation in Children with Autism Spectrum Disorder - A Retrospective Chart Review. Child Psychiatry Hum Dev 2022:10.1007/s10578-022-01461-1. [PMID: 36367616 DOI: 10.1007/s10578-022-01461-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/09/2022] [Indexed: 11/13/2022]
Abstract
AIMS AND OBJECTIVES Individual alpha frequency (IAF) is a biomarker of neurophysiological functioning. The IAF-guided repetitive transcranial magnetic stimulation (α-rTMS) is increasingly explored in diverse neurological conditions. However, there is limited data on the efficacy and safety of α-rTMS in children with autism spectrum disorder (ASD). MATERIALS AND METHODS The IAF, childhood autism rating scale (CARS), Pediatric Quality of Life Inventory 4.0 (PedsQLTM 4.0), and semi-structured interview data of patients that received 19 α-rTMS sessions (4 weeks) were aggregated and analysed using paired student t-test and descriptive method. RESULTS Data were retrieved from 28 patients (26 males, aged 3-9years (mean ± SD age: 6.1 ± 1.8years)). The post-α-rTMS data shows a significant improvement in IAF (9.4 Hz; p ≤ 0.025) towards 10 Hz. The CARS and PedsQLTM 4.0 surveys indicate that patients' ASD symptoms and quality of life improved significantly. Specifically, reports from semi-structured interviews suggest improved sleep trouble - the most significant comorbidity. The experiences of minor side effects such as hyperactivity resolved within two hours following α-rTMS sessions. CONCLUSION This study presents evidence on the efficacy and safety of α-rTMS in improving ASD symptoms, quality of life and comorbid sleep troubles in children. However, these findings should be interpreted as preliminary pending the presentation of double-blind, randomised clinical trials.
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Affiliation(s)
- Uchenna Ezedinma
- Brain Treatment Centre, 19-31 Dickson Road, Morayfield, QLD, Australia.
- University of the Sunshine Coast, Sippy Downs, Australia.
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Tan Z, Wei H, Song X, Mai W, Yan J, Ye W, Ling X, Hou L, Zhang S, Yan S, Xu H, Wang L. Positron Emission Tomography in the Neuroimaging of Autism Spectrum Disorder: A Review. Front Neurosci 2022; 16:806876. [PMID: 35495051 PMCID: PMC9043810 DOI: 10.3389/fnins.2022.806876] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 03/14/2022] [Indexed: 12/11/2022] Open
Abstract
Autism spectrum disorder (ASD) is a basket term for neurodevelopmental disorders characterized by marked impairments in social interactions, repetitive and stereotypical behaviors, and restricted interests and activities. Subtypes include (A) disorders with known genetic abnormalities including fragile X syndrome, Rett syndrome, and tuberous sclerosis and (B) idiopathic ASD, conditions with unknown etiologies. Positron emission tomography (PET) is a molecular imaging technology that can be utilized in vivo for dynamic and quantitative research, and is a valuable tool for exploring pathophysiological mechanisms, evaluating therapeutic efficacy, and accelerating drug development in ASD. Recently, several imaging studies on ASD have been published and physiological changes during ASD progression was disclosed by PET. This paper reviews the specific radioligands for PET imaging of critical biomarkers in ASD, and summarizes and discusses the similar and different discoveries in outcomes of previous studies. It is of great importance to identify general physiological changes in cerebral glucose metabolism, cerebral blood flow perfusion, abnormalities in neurotransmitter systems, and inflammation in the central nervous system in ASD, which may provide excellent points for further ASD research.
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Affiliation(s)
- Zhiqiang Tan
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Huiyi Wei
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Xiubao Song
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
| | - Wangxiang Mai
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
| | - Jiajian Yan
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
| | - Weijian Ye
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Xueying Ling
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Lu Hou
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Shaojuan Zhang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Sen Yan
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, China
| | - Hao Xu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
- *Correspondence: Hao Xu,
| | - Lu Wang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou, China
- Lu Wang,
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Xu S, Li M, Yang C, Fang X, Ye M, Wu Y, Yang B, Huang W, Li P, Ma X, Fu S, Yin Y, Tian J, Gan Y, Jiang G. Abnormal Degree Centrality in Children with Low-Function Autism Spectrum Disorders: A Sleeping-State Functional Magnetic Resonance Imaging Study. Neuropsychiatr Dis Treat 2022; 18:1363-1374. [PMID: 35818374 PMCID: PMC9270980 DOI: 10.2147/ndt.s367104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 06/23/2022] [Indexed: 12/04/2022] Open
Abstract
PURPOSE This study used the graph-theory approach, degree centrality (DC) to analyze whole-brain functional networks at the voxel level in children with ASD, and investigated whether DC changes were correlated with any clinical variables in ASD children. METHODS The current study included 86 children with ASD and 54 matched healthy subjects Aged 2-5.5 years. Next, chloral hydrate induced sleeping-state functional magnetic resonance imaging (ss-fMRI) datasets were acquired from these ASD and healthy subjects. For a given voxel, the DC was calculated by calculating the number of functional connections with significantly positive correlations at the individual level. Group differences were tested using two-sample t-tests (p < 0.01, AlphaSim corrected). Finally, relationships between abnormal DCs and clinical variables were investigated via Pearson's correlation analysis. RESULTS Children with ASD exhibited low DC values in the right middle frontal gyrus (MFG) (p < 0.01, AlphaSim corrected). Furthermore, significantly negative correlations were established between the decreased average DC values within the right MFG in ASD children and the total ABC scores, as well as with two ABC subscales measuring highly relevant impairments in ASD (ie, stereotypes and object-use behaviors and difficulties in language). CONCLUSION Taken together, the results of our ss-fMRI study suggest that abnormal DC may represent an important contribution to elucidation of the neuropathophysiological mechanisms of preschoolers with ASD.
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Affiliation(s)
- Shoujun Xu
- Department of Radiology, Shenzhen Children's Hospital, Shenzhen, People's Republic of China
| | - Meng Li
- Department of Medical Imaging, Guangdong Second Provincial General Hospital, Guangzhou, People's Republic of China
| | - Chunlan Yang
- Department of Hematology and Oncology, Shenzhen Children's Hospital, Shenzhen, People's Republic of China
| | - Xiangling Fang
- Department of Department of Children Healthcare, Shenzhen Children's Hospital, Shenzhen, People's Republic of China
| | - Miaoting Ye
- Department of Department of Children Healthcare, Shenzhen Children's Hospital, Shenzhen, People's Republic of China
| | - Yunfan Wu
- Department of Medical Imaging, Guangdong Second Provincial General Hospital, Guangzhou, People's Republic of China
| | - Binrang Yang
- Department of Department of Children Healthcare, Shenzhen Children's Hospital, Shenzhen, People's Republic of China
| | - Wenxian Huang
- Department of Department of Children Healthcare, Shenzhen Children's Hospital, Shenzhen, People's Republic of China
| | - Peng Li
- Department of Radiology, Shenzhen Children's Hospital, Shenzhen, People's Republic of China
| | - Xiaofen Ma
- Department of Medical Imaging, Guangdong Second Provincial General Hospital, Guangzhou, People's Republic of China
| | - Shishun Fu
- Department of Medical Imaging, Guangdong Second Provincial General Hospital, Guangzhou, People's Republic of China
| | - Yi Yin
- Department of Medical Imaging, Guangdong Second Provincial General Hospital, Guangzhou, People's Republic of China
| | - Junzhang Tian
- Department of Medical Imaging, Guangdong Second Provincial General Hospital, Guangzhou, People's Republic of China
| | - Yungen Gan
- Department of Radiology, Shenzhen Children's Hospital, Shenzhen, People's Republic of China
| | - Guihua Jiang
- Department of Medical Imaging, Guangdong Second Provincial General Hospital, Guangzhou, People's Republic of China
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Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) in autism research: literature review. Ir J Psychol Med 2021; 39:272-286. [PMID: 33818321 DOI: 10.1017/ipm.2021.15] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Autism spectrum disorder (ASD) remains a behaviourally defined condition. Its molecular basis is unknown; however, its prevalence has been increasing significantly. There have been several abnormalities in neurotransmitter systems reported in ASD. In our review, we described studies involving positron emission tomography (PET) and single-photon emission computed tomography (SPECT) that can provide useful and corroborative data. METHOD We conducted a literature review by comprehensive database searching on EMBASE, Scopus, PubMed, and PsychINFO looking for articles published since January 2009. Thirty-one studies were carefully selected - 22 PET studies and 9 SPECT studies - and reviewed by 2 independent researchers. References of the articles were also cross-checked. RESULTS Results of the studies, which mainly involve small groups of participants, are frequently inconclusive and often controversial due to the nature of ASD and its wide spectrum. Studies are conducted under different conditions and with poor control for confounding factors which creates difficulties in comparing the data. CONCLUSIONS There is ongoing need to improve methodology of the studies involving molecular imaging in ASD. Lack of consistent findings causes difficulties in evaluation, diagnosis, and treatment of the condition.
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Abstract
Autism is a grand challenge in global mental health to be dealt with on a priority basis. Phenotypic knowledge, biological understanding, and evidence-based intervention studies are all from western countries. We know very little about autism in the low- and middle-income countries (LMIC). Lack of infrastructure and difficulties in operationalizing research has widened the knowledge gap. We performed a comprehensive scoping review of research in Autism Spectrum Disorder in India to have an overall impression, identify gaps, and formulate evidence-based recommendations for further study. We searched PubMed, SCOPUS, and Cochrane Library to identify relevant Indian studies. A hundred and fifty-nine publications met the inclusion criteria. Most of the research contribution in autism is from few tertiary care medical centres, technological institutes, and not-for-profit organizations. We identified various themes of research like clinical profile, interventions, biomarkers, psychological, social, epidemiological, and risk factors. Evidence-based intervention studies, translation and adaptation of standard diagnostic instruments, and qualitative research on the experience of autism appeared to be state of the art. However, epidemiological studies, biomarkers identification, risk assessment studies were of low quality. There is a need for nationwide studies with representative sampling on epidemiology, biomarkers, and risk factors for a complete evaluation of the actual burden and biology of autism in India. Also, there is a need to design implementation research to evaluate the effectiveness of evidence-based interventions in routine healthcare settings. We recommend that future research should fill these gaps in understanding autism and improving its outcome in India.
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Affiliation(s)
- Suravi Patra
- Department of Psychiatry, All India Institute of Medical Sciences Bhubaneswar, Odisha, India
| | - Sujita Kumar Kar
- Department of Psychiatry, King George Medical University, Lucknow, Uttar Pradesh, India
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Abstract
Autism spectrum disorder (ASD) is a condition with onset in early childhood characterized by marked deficits in interpersonal interactions and communication and by a restricted and repetitive range of interests and activities. This review points out key recent findings utilizing molecular imaging including magnetic resonance spectroscopy (MRS) and nuclear neuroimaging techniques such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). MRS indicates an excitatory/inhibitory imbalance in high-functioning autism. Dysfunction of neurotransmitter and glucose metabolism has been demonstrated by PET and SPECT. Levels of serotonin synthesis in typically developing children are approximately twice those of adults; after the age of 5 years, levels decrease to those of adults. In contrast, levels of serotonin synthesis of children with ASD increase between ages 2 and 15 to 1.5-times adult values. The dopamine transporter is increased in the orbitofrontal cortex of men with ASD. The serotonin transporter is reduced in the brains of children, adolescents, and adults with ASD. Reduced serotonin receptors in the thalamus of adults with ASD are associated with communication difficulties. Glucose metabolism is reduced in the brains of people with ASD. Molecular imaging will provide the preliminary data for promising therapeutic interventions.
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Affiliation(s)
- Brian Jaeho Hwang
- a Department of Neuroscience , Zanvyl Krieger School of Arts and Sciences, Johns Hopkins University , Baltimore , MD , USA
| | - Mona Adel Mohamed
- b Division of Neuroradiology, The Russell H. Morgan Department of Radiology and Radiological Science School of Medicine , Johns Hopkins University , Baltimore , MD , USA
| | - James Robert Brašić
- c Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science , School of Medicine, Johns Hopkins University , Baltimore , MD , USA
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