Selective serotonin reuptake inhibitors (SSRIs) are the first-line treatment for major depressive disorder (MDD), yet their mechanisms of action are not fully understood and their therapeutic benefit ...varies among individuals. We used a targeted metabolomics approach utilizing a panel of 180 metabolites to gain insights into mechanisms of action and response to citalopram/escitalopram. Plasma samples from 136 participants with MDD enrolled into the Mayo Pharmacogenomics Research Network Antidepressant Medication Pharmacogenomic Study (PGRN-AMPS) were profiled at baseline and after 8 weeks of treatment. After treatment, we saw increased levels of short-chain acylcarnitines and decreased levels of medium-chain and long-chain acylcarnitines, suggesting an SSRI effect on β-oxidation and mitochondrial function. Amines-including arginine, proline, and methionine sulfoxide-were upregulated while serotonin and sarcosine were downregulated, suggesting an SSRI effect on urea cycle, one-carbon metabolism, and serotonin uptake. Eighteen lipids within the phosphatidylcholine (PC aa and ae) classes were upregulated. Changes in several lipid and amine levels correlated with changes in 17-item Hamilton Rating Scale for Depression scores (HRSD
). Differences in metabolic profiles at baseline and post-treatment were noted between participants who remitted (HRSD
≤ 7) and those who gained no meaningful benefits (<30% reduction in HRSD
). Remitters exhibited (a) higher baseline levels of C3, C5, alpha-aminoadipic acid, sarcosine, and serotonin; and (b) higher week-8 levels of PC aa C34:1, PC aa C34:2, PC aa C36:2, and PC aa C36:4. These findings suggest that mitochondrial energetics-including acylcarnitine metabolism, transport, and its link to β-oxidation-and lipid membrane remodeling may play roles in SSRI treatment response.
Deep brain stimulation (DBS) to the subcallosal cingulate cortex (SCC) is an emerging therapy for treatment resistant depression. Precision targeting of specific white matter fibers is now central to ...the model of SCC DBS treatment efficacy. A method to confirm SCC DBS target engagement is needed to reduce procedural variance across treatment providers and to optimize DBS parameters for individual patients. We examined the reliability of a novel cortical evoked response that is time-locked to a 2 Hz DBS pulse and shows the propagation of signal from the DBS target. The evoked response was detected in four individuals as a stereotyped series of components within 150 ms of a 6 V DBS pulse, each showing coherent topography on the head surface. Test-retest reliability across four repeated measures over 14 months met or exceeded standards for valid test construction in three of four patients. Several observations in this pilot sample demonstrate the prospective utility of this method to confirm surgical target engagement and instruct parameter selection. The topography of an orbital frontal component on the head surface showed specificity for patterns of forceps minor activation, which may provide a means to confirm DBS location with respect to key white matter structures. A divergent cortical response to unilateral stimulation of left (vs. right) hemisphere underscores the need for feedback acuity on the level of a single electrode, despite bilateral presentation of therapeutic stimulation. Results demonstrate viability of this method to explore patient-specific cortical responsivity to DBS for brain-circuit pathologies.
Past research has established that adverse childhood experiences (ACE) are correlated with depression severity. The purpose of the present study was to examine how the number and nature of ACE ...exposure is associated with symptomatology and treatment outcomes in adult patients with treatment resistant depression (TRD).
Participants include 454 patients with a diagnosis of major depression or persistent depressive disorder. A one-way analysis of variance (ANOVA) was used to assess whether number of ACEs was associated with certain outcomes. Linear regression analyses were performed to model the associations between the five ACE subtypes (e.g., sexual abuse, physical violence, injury/illness, childhood grief, and parental upheaval) and symptom severity. Logistic regression analyses were then used to model the association between ACE subtypes and history of lifetime suicide attempt(s) and inpatient admission(s).
Greater ACE exposure was associated with more severe symptomatology and treatment outcomes, but these differences were only seen between patients reporting no ACEs versus 3+ ACEs. Only the subtypes of violence and illness/injury were significant predictors of more severe symptomatology. The ACE subtypes of sexual trauma and violence uniquely predicted a lifetime suicide attempt(s), and only the subtype of sexual trauma predicted lifetime inpatient admission(s).
Limitations of the present study include retrospective adult assessments of childhood trauma, lack of data on ACE severity and timing, and the cross-sectional reporting of multiple study measures.
Exposure to multiple ACE subtypes, particularly sexual and physical trauma, is associated with depression symptom severity, and history of suicidality, and inpatient admission(s).
•Number and nature of adverse childhood experiences is associated with depression outcomes.•Greater childhood adversity exposure increases symptom and treatment outcome severity.•Childhood violence and sexual trauma may be driving this association.
Deep brain stimulation (DBS) of the subcallosal cingulate (SCC) is a promising intervention for treatment-resistant depression (TRD). Despite the failure of a clinical trial, multiple case series ...have described encouraging results, especially with the introduction of improved surgical protocols. Recent evidence further suggests that tractography targeting and intraoperative exposure to stimulation enhances early antidepressant effects that further evolve with ongoing chronic DBS. Accelerating treatment gains is critical to the care of this at-risk population, and identification of intraoperative electrophysiological biomarkers of early antidepressant effects will help guide future treatment protocols. Eight patients underwent intraoperative electrophysiological recording when bilateral DBS leads were implanted in the SCC using a connectomic approach at the site previously shown to optimize 6-month treatment outcomes. A machine learning classification method was used to discriminate between intracranial local field potentials (LFPs) recorded at baseline (stimulation-naïve) and after the first exposure to SCC DBS during surgical procedures. Spectral inputs (theta, 4-8 Hz; alpha, 9-12 Hz; beta, 13-30 Hz) to the model were then evaluated for importance to classifier success and tested as predictors of the antidepressant response. A decline in depression scores by 45.6% was observed after 1 week and this early antidepressant response correlated with a decrease in SCC LFP beta power, which most contributed to classifier success. Intraoperative exposure to therapeutic stimulation may result in an acute decrease in symptoms of depression following SCC DBS surgery. The correlation of symptom improvement with an intraoperative reduction in SCC beta power suggests this electrophysiological finding as a biomarker for treatment optimization.
Background Subcallosal cingulate white matter (SCC) deep brain stimulation (DBS) is an evolving investigational treatment for depression. Mechanisms of action are hypothesized to involve modulation ...of activity within a structurally defined network of brain regions involved in mood regulation. Diffusion tensor imaging was used to model white matter connections within this network to identify those critical for successful antidepressant response. Methods Preoperative high-resolution magnetic resonance imaging data, including diffusion tensor imaging, were acquired in 16 patients with treatment-resistant depression, who then received SCC DBS. Computerized tomography was used postoperatively to locate DBS contacts. The activation volume around the contacts used for chronic stimulation was modeled for each patient retrospectively. Probabilistic tractography was used to delineate the white matter tracts traveling through each activation volume. Patient-specific tract maps were calculated using whole-brain analysis. Clinical evaluations of therapeutic outcome from SCC DBS were defined at 6 months and 2 years. Results Whole-brain activation volume tractography demonstrated that all DBS responders at 6 months ( n = 6) and 2 years ( n = 12) shared bilateral pathways from their activation volumes to 1) medial frontal cortex via forceps minor and uncinate fasciculus; 2) rostral and dorsal cingulate cortex via the cingulum bundle; and 3) subcortical nuclei. Nonresponders did not consistently show these connections. Specific anatomical coordinates of the active contacts did not discriminate responders from nonresponders. Conclusions Patient-specific activation volume tractography modeling may identify critical tracts that mediate SCC DBS antidepressant response. This suggests a novel method for patient-specific target and stimulation parameter selection.
Create a software tool to facilitate tractography-based deep brain stimulation (DBS) electrode targeting within the patient-specific stereotactic coordinate system used in the operating room.
...StimVision was developed with Visualization Toolkit libraries and integrates four major components: 1) medical image visualization, 2) tractography visualization, 3) DBS electrode positioning, and 4) DBS activation volume calculation with tractography intersection.
Initial applications of StimVision are focused on the study of subcallosal cingulate (SCC) DBS for the treatment of depression. Retrospective modeling results on SCC DBS have suggested that direct stimulation of a specific collection of tractographic pathways are necessary for therapeutic benefit; thereby creating a tractography-based DBS surgical targeting hypotheses. StimVision is the tool we created to facilitate prospective clinical evaluation of that hypothesis.
Retrospective tractography-based analyses are common in DBS research; however, intraoperative software tools for interactive selection of a tractography-based DBS target are not readily available. StimVision provides an academic research tool to assist clinical implementation of new DBS targeting strategies and postoperative evaluation of targeting outcome.
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