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Preller KH, Scholpp J, Wunder A, Rosenbrock H. Neuroimaging Biomarkers for Drug Discovery and Development in Schizophrenia. Biol Psychiatry 2024; 96:666-673. [PMID: 38272287 DOI: 10.1016/j.biopsych.2024.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/19/2023] [Accepted: 01/14/2024] [Indexed: 01/27/2024]
Abstract
Schizophrenia is a chronic mental illness that affects up to 1% of the population. While efficacious therapies are available for positive symptoms, effective treatment of cognitive and negative symptoms remains an unmet need after decades of research. New developments in the field of neuroimaging are accelerating our knowledge gain regarding the underlying pathophysiology of symptoms in schizophrenia and psychosis spectrum disorders, inspiring new targets for drug development. However, no validated and qualified biomarkers are currently available to support the development of new therapeutics. This review summarizes the current use of neuroimaging technology in clinical drug development for psychotic disorders. As exemplified by drug development programs that target NMDA receptor hypofunction, neuroimaging results play a critical role in target discovery and establishing target engagement and dose selection. Furthermore, pharmacological neuroimaging may provide response biomarkers that allow for early decision making in proof-of-concept studies that leverage pharmacological challenge models in healthy volunteers. That said, while response and predictive biomarkers are starting to be evaluated in patient populations, they continue to play a limited role. Novel approaches to neuroimaging data acquisition and analysis may aid the establishment of biomarkers that are predictive at the individual level in the future. Nevertheless, various gaps in knowledge need to be addressed and biomarkers need to be validated to establish them as "fit for purpose" in drug development.
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Affiliation(s)
- Katrin H Preller
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany; Boehringer Ingelheim (Schweiz) GmbH, Basel, Switzerland.
| | - Joachim Scholpp
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Andreas Wunder
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Holger Rosenbrock
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
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2
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Uliana DL, Lisboa JRF, Gomes FV, Grace AA. The excitatory-inhibitory balance as a target for the development of novel drugs to treat schizophrenia. Biochem Pharmacol 2024; 228:116298. [PMID: 38782077 PMCID: PMC11410545 DOI: 10.1016/j.bcp.2024.116298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 05/13/2024] [Accepted: 05/16/2024] [Indexed: 05/25/2024]
Abstract
The intricate balance between excitation and inhibition (E/I) in the brain plays a crucial role in normative information processing. Dysfunctions in the E/I balance have been implicated in various psychiatric disorders, including schizophrenia (SCZ). In particular, abnormalities in GABAergic signaling, specifically in parvalbumin (PV)-containing interneurons, have been consistently observed in SCZ pathophysiology. PV interneuron function is vital for maintaining an ideal E/I balance, and alterations in PV interneuron-mediated inhibition contribute to circuit deficits observed in SCZ, including hippocampus hyperactivity and midbrain dopamine system overdrive. While current antipsychotic medications primarily target D2 dopamine receptors and are effective primarily in treating positive symptoms, novel therapeutic strategies aiming to restore the E/I balance could potentially mitigate not only positive symptoms but also negative symptoms and cognitive deficits. This could involve, for instance, increasing the inhibitory drive onto excitatory neurons or decreasing the putative enhanced pyramidal neuron activity due to functional loss of PV interneurons. Compounds targeting the glycine site at glutamate NMDA receptors and muscarinic acetylcholine receptors on PV interneurons that can increase PV interneuron drive, as well as drugs that increase the postsynaptic action of GABA, such as positive allosteric modulators of α5-GABA-A receptors, and decrease glutamatergic output, such as mGluR2/3 agonists, represent promising approaches. Preventive strategies aiming at E/I balance also represent a path to reduce the risk of transitioning to SCZ in high-risk individuals. Therefore, compounds with novel mechanisms targeting E/I balance provide optimism for more effective and tailored interventions in the management of SCZ.
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Affiliation(s)
- Daniela L Uliana
- Departments of Neuroscience, Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Joao Roberto F Lisboa
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Felipe V Gomes
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Anthony A Grace
- Departments of Neuroscience, Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, PA, USA.
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3
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Chang P, Pérez-González M, Constable J, Bush D, Cleverley K, Tybulewicz VLJ, Fisher EMC, Walker MC. Neuronal oscillations in cognition: Down syndrome as a model of mouse to human translation. Neuroscientist 2024:10738584241271414. [PMID: 39316548 DOI: 10.1177/10738584241271414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/26/2024]
Abstract
Down syndrome (DS), a prevalent cognitive disorder resulting from trisomy of human chromosome 21 (Hsa21), poses a significant global health concern. Affecting approximately 1 in 800 live births worldwide, DS is the leading genetic cause of intellectual disability and a major predisposing factor for early-onset Alzheimer's dementia. The estimated global population of individuals with DS is 6 million, with increasing prevalence due to advances in DS health care. Global efforts are dedicated to unraveling the mechanisms behind the varied clinical outcomes in DS. Recent studies on DS mouse models reveal disrupted neuronal circuits, providing insights into DS pathologies. Yet, translating these findings to humans faces challenges due to limited systematic electrophysiological analyses directly comparing human and mouse. Additionally, disparities in experimental procedures between the two species pose hurdles to successful translation. This review provides a concise overview of neuronal oscillations in human and rodent cognition. Focusing on recent DS mouse model studies, we highlight disruptions in associated brain function. We discuss various electrophysiological paradigms and suggest avenues for exploring molecular dysfunctions contributing to DS-related cognitive impairments. Deciphering neuronal oscillation intricacies holds promise for targeted therapies to alleviate cognitive disabilities in DS individuals.
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Affiliation(s)
- Pishan Chang
- Department of Neuromuscular Diseases, UCL Institute of Neurology, London, UK
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, UK
| | | | - Jessica Constable
- Department of Neuromuscular Diseases, UCL Institute of Neurology, London, UK
| | - Daniel Bush
- Department of Neuroscience, Physiology, and Pharmacology, UCL, London, UK
| | - Karen Cleverley
- Department of Neuromuscular Diseases, UCL Institute of Neurology, London, UK
| | - Victor L J Tybulewicz
- Immune Cell Biology and Down Syndrome Laboratory, The Francis Crick Institute, London, UK
| | | | - Matthew C Walker
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
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Sehatpour P, Kantrowitz JT. Finding the right dose: NMDAR modulating treatments for cognitive and plasticity deficits in schizophrenia and the role of pharmacodynamic target engagement. Biol Psychiatry 2024:S0006-3223(24)01552-X. [PMID: 39218136 DOI: 10.1016/j.biopsych.2024.08.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Revised: 08/20/2024] [Accepted: 08/20/2024] [Indexed: 09/04/2024]
Abstract
Cognitive impairment associated with schizophrenia (CIAS) and related deficits in learning (plasticity) are amongst the leading causes of disability in schizophrenia. Despite this, there are no FDA approved treatments for CIAS, and the development of treatments has been limited by numerous Phase II/III failures of compounds that showed initial promise in small-scale studies. N-methyl-d-aspartate-type glutamate receptors (NMDAR) have been proposed to play an important role in schizophrenia; moreover, NMDAR has a well characterized role in cognition, learning and neuroplasticity. We review prior published clinical trials in CIAS focusing on NMDAR modulator treatments, focusing on published and recent developments of the use of novel NMDAR-modulating treatments for CIAS both alone and combined with plasticity/learning paradigms to enhance learning. We will use this discussion of prior studies to highlight the importance of incorporating pharmacodynamic target engagement biomarkers early in treatment development, which can help predict which compounds will succeed or fail in Phase III. A range of direct and indirect NMDAR modulators will be covered, including d-serine, d-cycloserine, memantine, glycine and "first generation" glycine transport inhibitors (GTI, e.g. sarcosine and bitopertin), as well as recent positive studies of iclepertin, a novel GTI and luvadaxistat, a D-amino acid oxidase inhibitor (DAAO-I) that increases brain d-serine levels and indirect non-invasive brain stimulation NMDAR modulating treatments. Several examples of successful use of pharmacodynamic target engagement biomarkers for dose/drug discovery will be emphasized, including mismatch negativity (MMN), auditory steady state (ASSR) and time-frequency event-related potential (TF-ERP) approaches.
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Affiliation(s)
- Pejman Sehatpour
- New York State Psychiatric Institute, New York, NY; Columbia University, College of Physicians and Surgeons, New York, NY; Nathan Kline Institute, Orangeburg, NY
| | - Joshua T Kantrowitz
- New York State Psychiatric Institute, New York, NY; Columbia University, College of Physicians and Surgeons, New York, NY; Nathan Kline Institute, Orangeburg, NY.
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Yanagi M, Hashimoto M. Dysfunctional Parvalbumin Neurons in Schizophrenia and the Pathway to the Clinical Application of Kv3 Channel Modulators. Int J Mol Sci 2024; 25:8696. [PMID: 39201380 PMCID: PMC11354421 DOI: 10.3390/ijms25168696] [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: 06/29/2024] [Revised: 08/04/2024] [Accepted: 08/08/2024] [Indexed: 09/02/2024] Open
Abstract
Based on the pathophysiological changes observed in schizophrenia, the gamma-aminobutyric acid (GABA) hypothesis may facilitate the development of targeted treatments for this disease. This hypothesis, mainly derived from postmortem brain results, postulates dysfunctions in a subset of GABAergic neurons, particularly parvalbumin-containing interneurons. In the cerebral cortex, the fast spike firing of parvalbumin-positive GABAergic interneurons is regulated by the Kv3.1 and Kv3.2 channels, which belong to a potassium channel subfamily. Decreased Kv3.1 levels have been observed in the prefrontal cortex of patients with schizophrenia, prompting the investigation of Kv3 channel modulators for the treatment of schizophrenia. However, biomarkers that capture the dysfunction of parvalbumin neurons are required for these modulators to be effective in the pharmacotherapy of schizophrenia. Electroencephalography and magnetoencephalography studies have demonstrated impairments in evoked gamma oscillations in patients with schizophrenia, which may reflect the dysfunction of cortical parvalbumin neurons. This review summarizes these topics and provides an overview of how the development of therapeutics that incorporate biomarkers could innovate the treatment of schizophrenia and potentially change the targets of pharmacotherapy.
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Affiliation(s)
- Masaya Yanagi
- Department of Neuropsychiatry, Faculty of Medicine, Kindai University, 377-2 Ohnohigashi, Osaka-Sayama, Osaka 589-8511, Japan
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Vita A, Nibbio G, Barlati S. Pharmacological Treatment of Cognitive Impairment Associated With Schizophrenia: State of the Art and Future Perspectives. SCHIZOPHRENIA BULLETIN OPEN 2024; 5:sgae013. [PMID: 39144119 PMCID: PMC11207676 DOI: 10.1093/schizbullopen/sgae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/16/2024]
Abstract
Cognitive Impairment Associated with Schizophrenia (CIAS) represents one of the core dimensions of Schizophrenia Spectrum Disorders (SSD), with an important negative impact on real-world functional outcomes of people living with SSD. Treatment of CIAS represents a therapeutic goal of considerable importance, and while cognition-oriented evidence-based psychosocial interventions are available, effective pharmacological treatment could represent a game-changer in the lives of people with SSD. The present critical review reports and discusses the evidence regarding the effects of several pharmacological agents that are available in clinical practice or are under study, commenting on both current and future perspectives of CIAS treatment. In particular, the effects on CIAS of antipsychotic medications, anticholinergic medications, benzodiazepines, which are currently commonly used in the treatment of SSD, and of iclepertin, d-serine, luvadaxistat, xanomeline-trospium, ulotaront, anti-inflammatory molecules, and oxytocin, which are undergoing regulatory trials or can be considered as experimental agents, will be reported and discussed. Currently, available pharmacological agents do not appear to provide substantial benefits on CIAS, but accurate management of antipsychotic medications and avoiding treatments that can further exacerbate CIAS represent important strategies. Some molecules that are currently being investigated in Phase 2 and Phase 3 trials have provided very promising preliminary results, but more information is currently required to assess their effectiveness in real-world contexts and to provide clear recommendations regarding their use in clinical practice. The results of ongoing and future studies will reveal whether any of these molecules represents the awaited pharmacological game-changer in the treatment of CIAS.
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Affiliation(s)
- Antonio Vita
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
- Department of Mental Health and Addiction Services, ASST Spedali Civili of Brescia, Brescia, Italy
| | - Gabriele Nibbio
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Stefano Barlati
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
- Department of Mental Health and Addiction Services, ASST Spedali Civili of Brescia, Brescia, Italy
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Ranasinghe P, Addison ML, Dear JW, Webb DJ. Small interfering RNA: Discovery, pharmacology and clinical development-An introductory review. Br J Pharmacol 2023; 180:2697-2720. [PMID: 36250252 DOI: 10.1111/bph.15972] [Citation(s) in RCA: 43] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 08/23/2022] [Accepted: 09/29/2022] [Indexed: 11/28/2022] Open
Abstract
Post-transcriptional gene silencing targets and degrades mRNA transcripts, silencing the expression of specific genes. RNA interference technology, using synthetic structurally well-defined short double-stranded RNA (small interfering RNA [siRNA]), has advanced rapidly in recent years. This introductory review describes the utility of siRNA, by exploring the underpinning biology, pharmacology, recent advances and clinical developments, alongside potential limitations and ongoing challenges. Mediated by the RNA-induced silencing complex, siRNAs bind to specific complementary mRNAs, which are subsequently degraded. siRNA therapy offers advantages over other therapeutic approaches, including ability of specifically designed siRNAs to potentially target any mRNA and improved patient adherence through infrequent administration associated with a very long duration of action. Key pharmacokinetic and pharmacodynamic challenges include targeted administration, poor tissue penetration, nuclease inactivation, rapid renal elimination, immune activation and off-target effects. These have been overcome by chemical modification of siRNA and/or by utilising a range of delivery systems, increasing bioavailability and stability to allow successful clinical translation. Patisiran (hereditary transthyretin-mediated amyloidosis) was the first licensed siRNA, followed by givosiran (acute hepatic porphyria), lumasiran (primary hyperoxaluria type 1) and inclisiran (familial hypercholesterolaemia), which all use N-acetylgalactosamine (GalNAc) linkage for effective liver-directed delivery. Others are currently under development for indications varying from rare genetic diseases to common chronic non-communicable diseases (hypertension, cancer). Technological advances are paving the way for broader clinical use. Ongoing challenges remain in targeting organs beyond the liver and reaching special sites (e.g., brain). By overcoming these barriers, siRNA therapy has the potential to substantially widen its therapeutic impact.
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Affiliation(s)
- Priyanga Ranasinghe
- Department of Pharmacology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
| | - Melisande L Addison
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
| | - James W Dear
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
| | - David J Webb
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
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Surti TS, Ranganathan M, Johannesen JK, Gueorguieva R, Deaso E, Kenney JG, Krystal JH, D'Souza DC. Randomized controlled trial of the glycine transporter 1 inhibitor PF-03463275 to enhance cognitive training and neuroplasticity in schizophrenia. Schizophr Res 2023; 256:36-43. [PMID: 37141764 PMCID: PMC10257994 DOI: 10.1016/j.schres.2023.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 03/23/2023] [Accepted: 04/19/2023] [Indexed: 05/06/2023]
Abstract
N-methyl-d-aspartate glutamate receptor (NMDAR) hypofunction is implicated in the impaired neuroplasticity and cognitive impairments associated with schizophrenia (CIAS). We hypothesized that enhancing NMDAR function by inhibiting the glycine transporter-1 (GLYT1) would improve neuroplasticity and thereby augment benefits of non-pharmacological cognitive training (CT) strategies. This study examined whether co-administration of a GLYT1 inhibitor and computerized CT would have synergistic effects on CIAS. Stable outpatients with schizophrenia participated in this double-blind, placebo-controlled, within-subject, crossover augmentation study. Participants received placebo or GLYT1 inhibitor (PF-03463275) for two 5-week periods separated by 2 weeks of washout. PF-03463275 doses (40 or 60 mg twice daily) were selected to produce high GLYT1 occupancy. To limit pharmacodynamic variability, only cytochrome P450 2D6 extensive metabolizers were included. Medication adherence was confirmed daily. Participants received 4 weeks of CT in each treatment period. Cognitive performance (MATRICS Consensus Cognitive Battery) and psychotic symptoms (Positive and Negative Syndrome Scale) were assessed in each period. 71 participants were randomized. PF-03463275 in combination with CT was feasible, safe, and well-tolerated at the doses prescribed but did not produce greater improvement in CIAS compared to CT alone. PF-03463275 was not associated with improved CT learning parameters. Participation in CT was associated with improvement in MCCB scores.
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Affiliation(s)
- Toral S Surti
- Schizophrenia and Neuropharmacology Research Group, VA Connecticut Healthcare System, West Haven, CT, United States of America; Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, United States of America; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States of America.
| | - Mohini Ranganathan
- Schizophrenia and Neuropharmacology Research Group, VA Connecticut Healthcare System, West Haven, CT, United States of America; Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, United States of America; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States of America
| | - Jason K Johannesen
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States of America
| | - Ralitza Gueorguieva
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States of America
| | - Emma Deaso
- Schizophrenia and Neuropharmacology Research Group, VA Connecticut Healthcare System, West Haven, CT, United States of America; Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, United States of America; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States of America
| | - Joshua G Kenney
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States of America
| | - John H Krystal
- Schizophrenia and Neuropharmacology Research Group, VA Connecticut Healthcare System, West Haven, CT, United States of America; Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, United States of America; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States of America; Mental Health Service Line, Veterans Affairs Connecticut Healthcare System, West Haven, CT, United States of America
| | - Deepak Cyril D'Souza
- Schizophrenia and Neuropharmacology Research Group, VA Connecticut Healthcare System, West Haven, CT, United States of America; Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, United States of America; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States of America
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Yeh TC, Huang CCY, Chung YA, Park SY, Im JJ, Lin YY, Ma CC, Tzeng NS, Chang HA. Resting-State EEG Connectivity at High-Frequency Bands and Attentional Performance Dysfunction in Stabilized Schizophrenia Patients. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:medicina59040737. [PMID: 37109695 PMCID: PMC10141517 DOI: 10.3390/medicina59040737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/24/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023]
Abstract
Background and Objectives: Attentional dysfunction has long been viewed as one of the fundamental underlying cognitive deficits in schizophrenia. There is an urgent need to understand its neural underpinning and develop effective treatments. In the process of attention, neural oscillation has a central role in filtering information and allocating resources to either stimulus-driven or goal-relevant objects. Here, we asked if resting-state EEG connectivity correlated with attentional performance in schizophrenia patients. Materials and Methods: Resting-state EEG recordings were obtained from 72 stabilized patients with schizophrenia. Lagged phase synchronization (LPS) was used to measure whole-brain source-based functional connectivity between 84 intra-cortical current sources determined by eLORETA (exact low-resolution brain electromagnetic tomography) for five frequencies. The Conners' Continuous Performance Test-II (CPT-II) was administered for evaluating attentional performance. Linear regression with a non-parametric permutation randomization procedure was used to examine the correlations between the whole-brain functional connectivity and the CPT-II measures. Results: Greater beta-band right hemispheric fusiform gyrus (FG)-lingual gyrus (LG) functional connectivity predicted higher CPT-II variability scores (r = 0.44, p < 0.05, corrected), accounting for 19.5% of variance in the CPT-II VAR score. Greater gamma-band right hemispheric functional connectivity between the cuneus (Cu) and transverse temporal gyrus (TTG) and between Cu and the superior temporal gyrus (STG) predicted higher CPT-II hit reaction time (HRT) scores (both r = 0.50, p < 0.05, corrected), accounting for 24.6% and 25.1% of variance in the CPT-II HRT score, respectively. Greater gamma-band right hemispheric Cu-TTG functional connectivity predicted higher CPT-II HRT standard error (HRTSE) scores (r = 0.54, p < 0.05, corrected), accounting for 28.7% of variance in the CPT-II HRTSE score. Conclusions: Our study indicated that increased right hemispheric resting-state EEG functional connectivity at high frequencies was correlated with poorer focused attention in schizophrenia patients. If replicated, novel approaches to modulate these networks may yield selective, potent interventions for improving attention deficits in schizophrenia.
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Affiliation(s)
- Ta-Chuan Yeh
- Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei 114202, Taiwan
| | - Cathy Chia-Yu Huang
- Department of Life Sciences, National Central University, Taoyuan 320317, Taiwan
| | - Yong-An Chung
- Department of Nuclear Medicine, College of Medicine, The Catholic University of Korea, Seoul 07345, Republic of Korea
| | - Sonya Youngju Park
- Department of Nuclear Medicine, College of Medicine, The Catholic University of Korea, Seoul 07345, Republic of Korea
| | - Jooyeon Jamie Im
- Department of Psychology, Seoul National University, Seoul 08826, Republic of Korea
| | - Yen-Yue Lin
- Department of Life Sciences, National Central University, Taoyuan 320317, Taiwan
- Department of Emergency Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei 114202, Taiwan
- Department of Emergency Medicine, Taoyuan Armed Forces General Hospital, Taoyuan 325208, Taiwan
| | - Chin-Chao Ma
- Department of Psychiatry, Tri-Service General Hospital Beitou Branch, National Defense Medical Center, Taipei 112003, Taiwan
| | - Nian-Sheng Tzeng
- Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei 114202, Taiwan
| | - Hsin-An Chang
- Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei 114202, Taiwan
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The D-amino acid oxidase inhibitor luvadaxistat improves mismatch negativity in patients with schizophrenia in a randomized trial. Neuropsychopharmacology 2023; 48:1052-1059. [PMID: 36928351 PMCID: PMC10018616 DOI: 10.1038/s41386-023-01560-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/18/2023]
Abstract
Several attempts have been made to enhance N-methyl-D-aspartate (NMDA) receptor function in schizophrenia, but they have yielded mixed results. Luvadaxistat, a D-amino acid oxidase (DAAO) inhibitor that increases the glutamate co-agonist D-serine levels, is being developed for the treatment of cognitive impairment associated with schizophrenia. We conducted a biomarker study in patients, assessing several endpoints related to physiological outcomes of NMDA receptor modulation to determine whether luvadaxistat affects neural circuitry biomarkers relevant to NMDA receptor function and schizophrenia. This was a randomized, placebo-controlled, double-blind, two-period crossover phase 2a study assessing luvadaxistat 50 mg and 500 mg for 8 days in 31 patients with schizophrenia. There were no treatment effects of luvadaxistat at either dose in eyeblink conditioning, a cerebellar-dependent learning measure, compared with placebo. We observed a nominally significant improvement in mismatch negativity (MMN) and a statistical trend to improvement for auditory steady-state response at 40 Hz, in both cases with 50 mg, but not with 500 mg, compared with placebo. Although the data should be interpreted cautiously owing to the small sample size, they suggest that luvadaxistat can improve an illness-related circuitry biomarker at doses associated with partial DAAO inhibition. These results are consistent with 50 mg, but not higher doses, showing a signal of efficacy in cognitive endpoints in a larger phase 2, 12-week study conducted in parallel. Thus, MMN responses after a short treatment period may predict cognitive function improvement. MMN and ASSR should be considered as biomarkers in early trials addressing NMDA receptor hypofunction.
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