Inflammation-Induced CNS Glutamate Changes in Depression

Depression Clinical Trial

Official title: Inflammation-Induced CNS Glutamate Changes in Depression

Status Terminated

Clinical Trial Summary

Increased inflammation has been implicated in the pathophysiology of a number of neuropsychiatric illnesses including mood disorders, which affect almost 30 million adults in the United States alone. One mechanism by which inflammation may alter behavior is through increasing brain glutamate, a neurotransmitter that in excess has been implicated in neuronal toxicity and resistance to conventional antidepressant therapy. The goal of the proposed research is to test the hypothesis that inflammation alters behavior through increasing glutamate in specific brain regions, ultimately leading to behavioral changes.

The proposed research is designed to determine the cause and effect relationship between inflammation and CNS glutamate as well as the relationship between CNS glutamate and specific symptoms. To accomplish these aims, investigators will administer a single infusion of either the tumor necrosis factor (TNF) antagonist infliximab or placebo (n=30 per group) to patients with high inflammation (CRP>3mg/L). A CRP>3mg/L was chosen because it is considered high inflammation according to guidelines by the American Heart Association. Moreover, a CRP>3mg/L is associated with significantly increased basal ganglia glutamate and with a clinical response to infliximab. Inflammatory biomarkers, basal ganglia glutamate as measured by MRS, and motivation and psychomotor activity will be assessed at baseline and days 1 and 3 and weeks 1 and 2 following infliximab or placebo administration.

Clinical Trial Description

This study aims to test the hypothesis that increased inflammation causes increased basal ganglia glutamate and consequently anhedonia and psychomotor retardation in patients with major depressive disorder (MDD). Excessive inflammation and glutamate excitotoxicity are two pathways that have received increasing attention regarding the pathophysiology of neuropsychiatric disease including mood disorders. Patients with depression exhibit increased peripheral and central nervous system (CNS) markers of inflammation as well as altered CNS glutamate as measured by magnetic resonance spectroscopy (MRS). In addition, drugs that block either inflammation or glutamate signaling can reverse depressive symptoms, especially in depressed patients with treatment resistance.

Inflammatory cytokines are known to inhibit glutamate reuptake and increase glutamate release from astrocytes, and glutamate antagonists have been shown to block inflammation-induced depressive-like behavior in mice. Moreover, using MRS, data has shown that administration of the inflammatory cytokine interferon (IFN)-alpha significantly increases glutamate in the basal ganglia in association with IFN-alpha-induced anhedonia and psychomotor slowing. In addition, increased inflammation as reflected by peripheral blood C-reactive protein (CRP) is correlated with increased basal ganglia glutamate in association with decreased motivation and psychomotor speed in patients with MDD. Nevertheless, the data to date has been correlational, and whether increased inflammation causes increased glutamate in the basal ganglia, which in turn contributes to behavioral changes in patients with depression has not been established.

To test this hypothesis, investigators plan to determine the cause and effect relationship between increased inflammation and increased CNS glutamate by blocking inflammation in depressed patients with high inflammation (CRP>3mg/L) using the highly specific tumor necrosis factor (TNF) antagonist infliximab (n=30) versus placebo (n=30). In addition, the study team will examine whether changes in basal ganglia glutamate are linked to changes in behaviors related to the basal ganglia including anhedonia and psychomotor retardation. ;

Related Conditions & MeSH terms

• Depression
• Depressive Disorder
• Inflammation

• NCT number: NCT03004443
• Study type: Interventional
• Source: Emory University
• Status: Terminated
• Phase: Phase 4
• Start date: May 15, 2017
• Completion date: November 27, 2019