Vagus Nerve Stimulation Modulates Inflammation in Treatment-Resistant Depression Patients: A Pilot Study.

Vagal neurostimulation (VNS) is used for the treatment of epilepsy and major medical-refractory depression. VNS has neuropsychiatric functions and systemic anti-inflammatory activity. The objective of this study is to measure the clinical efficacy and impact of VNS modulation in depressive patients. Six patients with refractory depression were enrolled. Depression symptoms were assessed with the Montgomery-Asberg Depression Rating, and anxiety symptoms with the Hamilton Anxiety Rating Scale. Plasmas were harvested prospectively before the implantation of VNS (baseline) and up to 4 years or more after continuous therapy. Forty soluble molecules were measured in the plasma by multiplex assays. Following VNS, the reduction in the mean depression severity score was 59.9% and the response rate was 87%. Anxiety levels were also greatly reduced. IL-7, CXCL8, CCL2, CCL13, CCL17, CCL22, Flt-1 and VEGFc levels were significantly lowered, whereas bFGF levels were increased (p values ranging from 0.004 to 0.02). This exploratory study is the first to focus on the long-term efficacy of VNS and its consequences on inflammatory biomarkers. VNS may modulate inflammation via an increase in blood-brain barrier integrity and a reduction in inflammatory cell recruitment. This opens the door to new pathways involved in the treatment of refractory depression.

Intravenous ketamine for treatment-resistant depression patients who have failed to respond to transcranial magnetic stimulation: A case series.

BACKGROUND: For individuals with treatment-resistant depression (TRD), transcranial magnetic stimulation (TMS) has become a well-established approach. In the past decade, intravenous (IV) racemic ketamine has also emerged as a potential treatment for TRD. Currently, little data is available on the clinical effects of IV racemic ketamine in TRD patients who experienced TMS-failure. METHODS: Twenty-one (21) TRD patients who had failed to respond to a standard course of high-frequency left-dorsolateral prefrontal cortex TMS were subsequently scheduled to received IV racemic ketamine infusions. The IV racemic ketamine protocol consisted of 0,5 mg/kg infusions over 60 min, 3 times a week over 2 weeks. RESULTS: Treatment was safe with minimal side-effects. Mean baseline MADRS score was 27.6 ± 6.4 (moderate depression), decreasing down to 18.6 ± 8.9 (mild depression) post-treatment. Mean percent improvement was 34.5 % ± 21.1 from baseline to post-treatment. Paired sample t-test showed significant MADRS score decrease pre- to post-treatment [t(20) = 7.212, p < .001]. Overall, four (4) patients (19.0 %) responded and two (2) of those achieved remission (9.5 %). LIMITATIONS: Limitations of this case series include its retrospective and uncontrolled open-label nature, the lack of self-rating and standardized adverse events questionnaires, as well as follow-ups beyond the immediate treatment period. CONCLUSIONS: Novel ways to increase the clinical effects of ketamine are being explored. We discuss potential combination approaches of ketamine with other modalities to augment its effects. Given the global burden of TRD, novel approaches are needed to curb the current mental health epidemic around the world.

Transcranial magnetic stimulation and intravenous ketamine combination therapy for treatment-resistant bipolar depression: A case report.

About a third of patients suffering from major depression develop treatment-resistant depression (TRD). Although repetitive transcranial magnetic stimulation (rTMS) and intravenous ketamine have proven effective for the management of TRD, many patients remain refractory to treatment. We present the case of a patient suffering from bipolar TRD. The patient was referred to us after failure to respond to first-and second-line pharmacotherapy and psychotherapy. After minimal response to both rTMS and ketamine alone, we attempted a combination rTMS and ketamine protocol, which led to complete and sustained remission. Various comparable and complimentary mechanisms of antidepressant action of ketamine and rTMS are discussed, which support further study of this combination therapy. Future research should focus on the feasibility, tolerability, and efficacy of this novel approach.

Sex and Gender and Allostatic Mechanisms of Cardiovascular Risk and Disease.

Cardiovascular diseases are leading causes of mortality and morbidity in adults worldwide. Multiple studies suggest that there are clinically relevant sex differences in cardiovascular disease. Women and men differ substantially in terms of prevalence, presentation, management, and outcomes of cardiovascular disease. To date, however, little is known about why cardiovascular disease affects women and men differently. Because many studies do not differentiate the concept of sex and gender, it is sometimes difficult to discriminate sociocultural vs biological contributors that drive observed clinical differences. Female sex has some biological advantages in relation to cardiovascular disease, but many of these advantages seem to disappear as soon as women develop cardiovascular risk factors (eg, type 2 diabetes, hypertension, dyslipidemia). Furthermore, stress and allostatic load could play an important role in the relationship between sex/gender and cardiovascular diseases. In this narrative review, we argue that chronic stress and psychosocial factors might better encompass the patterns of allostatic load increases seen in women, while biological risk factors and unhealthy behaviours might be more important mechanisms that drive increased allostatic load in men. Indeed, men show allostatic load patterns that are more associated with impaired anthropometric, metabolic, and cardiovascular functioning and women have greater dysregulation in neuroendocrine and immune functioning. Thus gender-related factors might contribute to the pathogenesis of cardiovascular disease especially through stress mechanisms. It is important to continue to study the mechanisms by which gender influences chronic stress, because chronic stress could influence modifiable gendered factors to promote cardiovascular disease prevention.

Prolonged intermittent theta burst stimulation in the treatment of major depressive disorder: a case series.

Intermittent theta burst stimulation (iTBS) using 600 pulses is an effective and FDA-cleared transcranial magnetic stimulation (TMS) protocol for major depressive disorder (MDD). Prolonged iTBS (piTBS) using 1,800 pulses could increase the effectiveness of TMS for MDD, but its real-world effectiveness is still debated. We assessed the safety, tolerability, and preliminary effectiveness of a 3x daily piTBS 1,800 pulses protocol delivered over 2 weeks in 27 participants. Only four participants (18.2%) achieved response, two of them achieving remission (9.1%). Five participants (18.5%) experienced tolerability issues. Future studies should focus on the neurophysiological effects of TBS protocols to determine optimal parameters.

Allostatic load as a predictor of response to repetitive transcranial magnetic stimulation in treatment resistant depression: Research protocol and hypotheses.

Treatment resistant depression is challenging because patients who fail their initial treatments often do not respond to subsequent trials and their course of illness is frequently marked by chronic depression. Repetitive transcranial magnetic stimulation (rTMS) is a well-established treatment alternative, but there are several limitations that decreases accessibility. Identifying biomarkers that can help clinicians to reliably predict response to rTMS is therefore necessary. Allostatic load (AL), which represents the 'wear and tear' on the body and brain which accumulates as an individual is exposed to chronic stress could be an interesting staging model for TRD and help predict rTMS treatment response. We propose an open study which aims to test whether patients with a lower pre-treatment AL will have a stronger antidepressant response to 4 week-rTMS treatment. We will also assess the relation between healthy lifestyle behaviors, AL, and rTMS treatment response. Blood samples for AL parameters will be collected before the treatment. The AL indices will summarize neuroendocrine (cortisol, Dehydroepiandrosterone), immune (CRP, fibrinogen, ferritin), metabolic (glycosylated hemoglobin, total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, uric acid, body mass index, waist circumference), and cardiovascular (heart rate, systolic and diastolic blood pressure) functioning. Mood assessment (Montgomery-Åsberg Depression Rating Scale and Inventory of Depressive symptomatology) will be measured before the treatment and at two-week intervals up to 4 weeks. With the help of different lifestyle questionnaires, a healthy lifestyle index (i.e., a single score based on lifestyle factors) will be created. We will use linear and logistic regressions to assess AL in relation to changes in mood score. Hierarchical regression will be done in order to assess the association between AL, healthy lifestyle index and mood score. Long-lasting and unsuccessful antidepressant trials may increase the chance of not responding to future trials of antidepressants and it can therefore increase treatment resistance. It is essential to identify reliable biomarkers that can predict treatment responses.

Vagus Nerve Stimulation for Treatment-Resistant Depression: a Case Series of Clinical Symptoms Associated with the End of Service Period.

BACKGROUND: This work describes the clinical symptoms associated with end of service (EOS) of the batteries of vagus nerve stimulation (VNS) generators in treatment-resistant depression (TRD). Because neurostimulator software may not provide reliable information on battery depletion, careful monitoring of clinical symptoms during the EOS period is an important concern in the follow-up of TRD patients treated with VNS therapy. METHODS: Twenty-six (26) patients were implanted and followed at the Centre Hospitalier de l'Université de Montréal. Fourteen (14) patients required battery replacement and we retrieved chart data up to 3 months before generator battery replacement. RESULTS: Our study demonstrated there might be a decrease or increase in VNS associated physical side effects, and possibly an increase in depressive symptoms during EOS. LIMITATIONS: Our observations are limited by the retrospective nature of this small case series, and larger prospective studies evaluating both VNS side effects and depressive symptoms are therefore needed to further validate those findings. CONCLUSION: Our study is the first to examine clinical symptoms associated with EOS of the batteries of VNS in TRD.

Electrocardiogram Corrected Q-T Interval Predicts Response to Vagus Nerve Stimulation in Depression.

INTRODUCTION: Recent studies have revealed a possible link between heart rate variability (HRV) and major depressive disorder (MDD), with decreased HRV in MDD compared with healthy subjects. Corrected Q-T interval (QTc) has been suggested to represent an indirect estimate of HRV, as QTc length is inversely correlated to parasympathetic activity in healthy subjects. This retrospective study assessed the ability of QTc length in predicting response to vagus nerve stimulation (VNS) treatment in refractory depression. METHODS: We measured QTc length in 19 patients suffering from refractory depression, selected to be implanted with VNS. Correlations were calculated between baseline QTc (preimplantation) and long-term mood response. RESULTS: Nineteen patients selected for VNS surgery were included in the study. Baseline 28-item Hamilton Depression Rating Scale scores were 28.5 ± 6.8 and decreased to 15.1 ± 9.5 at 12 months and 12.4 ± 10.4 at 24 months post-VNS. Among the 19 patients, 53% (10) were responders and 26% (5) were in remission at 12 months. Pretreatment QTc averaged 425.5 ± 22.0. Patients with longer baseline QTc displayed larger improvement, with a significant correlation between mood and QTc values after 12 months (r(18) = -0.526, P = 0.02) and also after 24 months of VNS therapy (r(17) = -0.573, P = 0.016). CONCLUSIONS: The presented analysis showed that increased QTc in patients with MDD might be used as a baseline biomarker for depressive episodes that might respond preferentially to VNS. The link between cardiovagal activity in depression and response to VNS treatment requires further investigation in larger cohorts and randomized controlled trials.