(GluEsk) Glutamate and Esketamine

Depression Clinical Trial

— GluEsk  

Official title:

Effects of Esketamine Challenge on Brain Glutamate Release (fMRS), Resting State Connectivity (BOLD-rs-fMRI), and Neuroplasticity (Visual Task)

Clinical Trial Details — Status: Not yet recruiting

Administrative data

• NCT number: NCT06432322
• Other study ID #: R90468/RE001
• Status: Not yet recruiting
• Phase: N/A
• Start date: June 2024
• Est. completion date: June 2025

Study information

• Verified date: May 2024
• Source: University of Oxford
• Contact: Wendy Howard
• Phone: 01865 618238
• Email: wendy.howard[@]psych.ox.ac.uk
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

Esketamine is the S-enantiomer of racemic ketamine, a N-methyl-D-aspartate (NMDA) receptor antagonist. Esketamine and other antidepressant NMDA receptor antagonists are hypothesised to act by producing a rapid increase in brain glutamate release, which then stimulates α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. This activity in turn is thought to restore synaptic functioning, neuroplasticity, and connectivity in brain regions involved in mood regulation, which would be ultimately responsible for the antidepressant effect of esketamine However, the effect of esketamine on glutamate release in humans has not previously been studied. In this study we therefore aim to ascertain the effect of esketamine on brain glutamate release, resting state connectivity, and neuroplasticity as measured via fMRS, BOLD-rs-fMRI, and a behavioural computerised visual task respectively.

Description:

There is growing interest in the use of antagonists at the glutamate N-methyl-D-aspartate (NMDA) receptor in patients with treatment-resistant depression (TRD). Work in animal studies suggests that NMDA receptor antagonists act initially by increasing brain glutamate release, but whether such an action occurs in humans is not established.

Esketamine is the S-enantiomer of racemic ketamine: a non-selective, non-competitive, antagonist of the ionotropic glutamate NMDA receptor . It is the only NMDA receptor antagonist licensed in the UK for the treatment of patients with TRD. Esketamine is administered intranasally: it is rapidly absorbed by the nasal mucosa following nasal administration and can be measured in plasma within 7 minutes following a 28 mg dose. The time to reach maximum plasma concentration (tmax) is typically 20 to 40 minutes after the last nasal spray of a treatment session. It is hypothesised that through NMDA receptor antagonism, esketamine produces a transient increase in glutamate release leading to increases in α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor stimulation and subsequently to increases in neurotrophic signalling which may contribute to the restoration of synaptic function, neuroplasticity, and connectivity in brain regions involved with the regulation of mood.

Glutamate is the primary excitatory neurotransmitter in the brain and has been implicated in several neuropsychiatric disorders. "Gold-standard" methods to assess glutamate activity in the living human brain are expensive and involve radioactive injections and invasive blood sampling. More recently, work in our Clinical Psychopharmacology laboratory has shown that 7T fMRS (a more widely available, non-invasive, safe technique) that uses a visual stimulus ("flickering checkerboard") can reliably and sensitively measure changes in brain glutamate release. No prior study however has shown whether this effect is susceptible to pharmacological challenge. We therefore propose to assess whether through its NMDA/AMPA-mediated activity, esketamine can indeed produce an increase in brain glutamate release measured via this technique.

The aims of this study are to investigate the effect of esketamine on brain glutamate release and resting state connectivity, and on vision. Therefore, the primary objective of this study is to assess the effect of a single dose of esketamine 56mg intranasal vs placebo on brain glutamate release changes measured via 7T fMRS "flickering checkerboard" stimulus. Secondary objectives include the investigation of the effects of esketamine on brain resting state connectivity changes measured via 7T BOLD-rs-fMRI, and on neuroplasticity measured via a behavioural computerised visual task. Psychological questionnaires will also be measured to check for possible correlations with the outcomes measured.

Recruitment information / eligibility

• Status: Not yet recruiting
• Enrollment: 12
• Est. completion date: June 2025
• Est. primary completion date: June 2025
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 50 Years

Eligibility

Inclusion Criteria:

• Aged 18 to 50 years

• Body Mass Index in the range of 18-30

• Sufficiently fluent in English to understand the study instructions

• Willing and able to give informed consent for participation in the research

Exclusion Criteria:

• Currently on any regular prescribed medications (except the contraceptive pill), unless unlikely to compromise safety or affect data quality in the opinion of the Investigator

• Known hypersensitivity to the study drug (i.e., esketamine)

• History of, or current significant alcohol or substance misuse disorder

• Any use of recreational drugs over the last 3 months

• Any lifetime use of ketamine or phencyclidine (PCP)

• Currently smoking >/=20 cigarettes/day

• History of, or current significant cardiovascular disorder (e.g., hypertension, myocardial infarction)

• History of, or current significant neurological disorder (e.g., epilepsy, migraine) or cerebrovascular disorder (e.g., haemorrhagic or ischemic stroke, aneurysmal vascular disease, raised intracranial pressure)

• History of, or current significant respiratory, hepatic, urinary tract, or thyroid disorders

• History of, or current acute porphyria

• History of, or current significant psychiatric disorder (e.g., psychosis, mania, depression)

• History of, or current eye disorder, not including refractive error that can be corrected with glasses or contact lenses)

• Pregnant, breast feeding, women of child-bearing potential not using appropriate contraceptive measures

• Any contraindication to 7T MRI (see Approved Procedure: IDREC_17 Title: Non-invasive Magnetic Resonance Investigations in Healthy Volunteers)

Related Conditions & MeSH terms

• Depression

Intervention

Drug:
• Esketamine nasal spray
Nasal spray solution, 56mg (28mg per nostril), intranasal

Other:
• Placebo
Nasal spray solution, 0.9% NaCl, intranasal

Locations

Country	Name	City	State
United Kingdom	Department of Psychiatry, University of Oxford	Oxford	Oxfordshire

Sponsors (2)

Lead Sponsor	Collaborator
University of Oxford	NIHR Oxford Health Biomedical Research Centre

Country where clinical trial is conducted

United Kingdom, 

References & Publications (4)

Ip IB, Berrington A, Hess AT, Parker AJ, Emir UE, Bridge H. Combined fMRI-MRS acquires simultaneous glutamate and BOLD-fMRI signals in the human brain. Neuroimage. 2017 Jul 15;155:113-119. doi: 10.1016/j.neuroimage.2017.04.030. Epub 2017 Apr 19. — View Citation

Jewett BE, Thapa B. Physiology, NMDA Receptor. 2022 Dec 11. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from http://www.ncbi.nlm.nih.gov/books/NBK519495/ — View Citation

Li CT, Yang KC, Lin WC. Glutamatergic Dysfunction and Glutamatergic Compounds for Major Psychiatric Disorders: Evidence From Clinical Neuroimaging Studies. Front Psychiatry. 2019 Jan 24;9:767. doi: 10.3389/fpsyt.2018.00767. eCollection 2018. — View Citation

Rosenbaum SB, Gupta V, Patel P, Palacios JL. Ketamine. 2024 Jan 30. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from http://www.ncbi.nlm.nih.gov/books/NBK470357/ — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Brain glutamate release	Brain glutamate release change measured via functional Magnetic Resonance Spectroscopy (fMRS) 7-Tesla (7T) "flickering checkerboard", comparing drug vs placebo occasions.	Acute (40-60 minutes after nasal spray application)
Secondary	Brain resting state connectivity	Brain resting state connectivity change measured via blood oxygenation level-dependent resting-state functional Magnetic Resonance Imaging (BOLD-rs-fMRI) 7T, comparing drug vs placebo occasions.	Acute (40-60 minutes after nasal spray application)
Secondary	Visual response	Behavioural visual response measured via a computerised visual task, comparing drug vs placebo occasions.	Post-Acute (60-90 minutes after nasal spray application)

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