Transcriptomic signatures of treatment response to the combination of escitalopram and memantine or placebo in late-life depression

Identification of blood transcriptome modules associated with suicidal ideation in patients with major depressive disorder

The risk of suicide in patients with major depressive disorder (MDD) poses a major concern, with studies suggesting that genetics may be a contributing factor. Although there are many transcriptomic studies on postmortem brain tissue related to suicidal behavior, the blood transcriptional mechanisms of suicidal ideation (SI) remain unknown. This study utilized a weighted gene coexpression network analysis (WGCNA) approach to investigate the associations between gene coexpression modules and SI in individuals with MDD using peripheral blood RNA-seq data from 75 MDD patients with SI (MDD_SI), 82 MDD patients without SI (MDD_nSI), and 149 healthy controls (HC). An ANCOVA was conducted to assess differences in gene coexpression modules among groups, with age and sex included as covariates. The gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) databases were used to annotate module functions. Results indicated that the magenta module (associated with RNA splicing processes) differentiated MDD_SI from MDD_nSI (p = 0.021), while the green module (related to immune and inflammatory responses) distinguished MDD_SI from HC (p = 0.004). Additionally, three modules showed differences between MDD_nSI and HC: magenta (p = 0.009), brown (related to innate immunity and mitochondrial metabolism; p = 0.001), and turquoise (associated with energy metabolism and neurodegeneration; p = 0.005). Our findings highlight that gene expression regulation, immune response, and inflammation may be linked to SI in patients with MDD, while pathways associated with innate immunity, energy metabolism, mitochondrial function, and neurodegeneration appear to be more broadly related to MDD.

Association of Molecular Senescence Markers in Late-Life Depression With Clinical Characteristics and Treatment Outcome

IMPORTANCE

Many older adults with depression do not experience remission with antidepressant treatment, and markers of cellular senescence in late-life depression (LLD) are associated with greater severity of depression, greater executive dysfunction, and higher medical illness burden. Since these clinical characteristics are associated with remission in LLD, molecular and cellular senescence abnormalities could be a possible biological mechanism underlying poor treatment response in this population.

OBJECTIVE

To examine whether the senescence-associated secretory phenotype (SASP) index was associated with the likelihood of remission from a depressive episode in older adults.

DESIGN, SETTING, AND PARTICIPANTS

A nonrandomized, open-label clinical trial was conducted between August 2009 and August 2014 in Pittsburgh, Pennsylvania; St Louis, Missouri; and Toronto, Ontario, Canada, with older adults in a current major depressive episode according to the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision) diagnostic criteria. Data from biomarker analyses were reported according to the clinical trial archived plasma samples run in March 2021. Data were analyzed from June to November 2021.

EXPOSURE

Venlafaxine extended release (dose ranging from 37.5 mg to 300 mg daily) for up to 12 weeks.

MAIN OUTCOMES AND MEASURES

The association between a composite biomarker-based index (SASP index) and treatment remission in older adults with major depression was measured using clinical data and blood samples.

RESULTS

There were 416 participants with a mean (SD) age of 60.02 (7.13) years; 64% (265 participants) were self-reported female, and the mean (SD) Montgomery-Asberg Depression Rating Scale score was 26.6 (5.7). Higher SASP index scores were independently associated with higher rates of nonremission, with an increase of 1 unit in the SASP index score increasing the odds of nonremission by 19% (adjusted odds ratio, 1.19; 95% CI, 1.05-1.35; P = .006). In contrast, no individual SASP factors were associated with remission in LLD.

CONCLUSIONS AND RELEVANCE

Using clinical data and blood samples from a nonrandomized clinical trial, the results of this study suggest that molecular and cellular senescence, as measured with the SASP index, is associated with worse treatment outcomes in LLD. Combining this index score reflecting interrelated biological processes with other molecular, clinical, and neuroimaging markers may be useful in evaluating antidepressant treatment outcomes. These findings inform a path forward for geroscience-guided interventions targeting senescence to improve remission rates in LLD.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00892047.

Default mode network connectivity and treatment response in geriatric depression

OBJECTIVES

Default mode network (DMN) connectivity is altered in depression. We evaluated the relationship between changes in within-network DMN connectivity and improvement in depression in a subsample of our parent clinical trial comparing escitalopram/memantine (ESC/MEM) to escitalopram/placebo (ESC/PBO) in older depressed adults (NCT01902004).

METHODS

Twenty-six participants with major depression (age > 60 years) and subjective memory complaints underwent treatment with ESC/MEM (n = 13) or ESC/PBO (n = 13), and completed baseline and 3-month follow-up resting state magnetic resonance imaging scans. Multi-block partial least squares correlation analysis was used to evaluate the impact of treatment on within-network DMN connectivity changes and their relationship with symptom improvement at 3 months (controlling for age and sex).

RESULTS

A significant latent variable was identified, reflecting within-network DMN connectivity changes correlated with symptom improvement (p = .01). Specifically, although overall group differences in within-network DMN connectivity changes failed to reach significance, increased within-network connectivity of posterior/lateral DMN regions (precuneus, angular gyrus, superior/middle temporal cortex) was more strongly and positively correlated with symptom improvement in the ESC/MEM group (r = 0.97, 95% confidence interval: 0.86-0.98) than in the ESC/PBO group (r = 0.36, 95% confidence interval: 0.13-0.72).

CONCLUSIONS

Increased within-network connectivity of core DMN nodes was more strongly correlated with depressive symptom improvement with ESC/MEM than with ESC/PBO, supporting an improved engagement of brain circuitry implicated in the amelioration of depressive symptoms with combined ESC/MEM treatment in older adults with depression and subjective memory complaints.

Memantine can protect against inflammation-based cognitive decline in geriatric depression

INTRODUCTION

Geriatric depression is frequently accompanied by cognitive complaints and inflammation that increase risk for treatment-resistant depression and dementia. Memantine, a neuroprotective drug, can improve depression, inflammation, and help prevent cognitive decline. In our six-month clinical trial, escitalopram/memantine (ESC/MEM) improved mood and cognition compared to escitalopram/placebo treatment (ESC/PBO; NCT01902004). In this report, we examined the impact of baseline inflammation on mood and cognitive outcomes.

MATERIALS AND METHODS

We measured a panel of inflammatory cytokine markers using Human 38-plex magnetic cytokine/chemokine kits (EMD Millipore, HCYTMAG-60K-PX38) in 90 older adults 60 years and older with major depression enrolled in a 6-month double-blind placebo-controlled trial of escitalopram ​+ ​memantine (ESC/MEM) in depressed older adults with subjective memory complaints. Four cytokine factors were derived and linear models were estimated to examine the predictive ability of cytokine levels on treatment induced change in depression and cognition.

RESULTS

Of the 90 randomized participants, 62 completed the 6-month follow up assessment. Both groups improved significantly on depression severity (HAM-D score), but not on cognitive outcomes at six months. Cytokine factor scores were not significantly different between ESC/MEM (n ​= ​45) and ESC/PBO (n ​= ​45) at baseline. Pro-inflammatory biomarkers at baseline predicted a decline in executive functioning in the ESC/PBO group but not in the ESC/MEM group, interaction F(1,52) ​= ​4.63, p ​= ​.04.

DISCUSSION

In this exploratory analysis, the addition of memantine to escitalopram provided a protective effect on executive functioning in older depressed adults. Future studies are needed to replicate the association of cytokine markers to antidepressant and neuroprotective treatment-related change in cognition in geriatric depression.