An assessment of the anti-fatigue effects of ketamine from a double-blind, placebo-controlled, crossover study in bipolar disorder

The effect of intranasal (R,S)-ketamine on symptoms of fatigue in severe major depressive disorder or bipolar depression with and without comorbid alcohol use disorder: Results from a randomized, double-blind, placebo-controlled trial

BACKGROUND

Fatigue is a multidimensional condition that may overlap with depression. Initial studies found that fatigue responds in only a limited way to standard monoaminergic antidepressants and mood stabilizers but does respond positively to intravenous (IV) racemic (R,S)-ketamine (ketamine). However, IV ketamine's use is limited by cost and access barriers. To date, no study has evaluated intranasal (IN) ketamine in individuals with fatigue. This study sought to evaluate the anti-fatigue effects of a single 50 mg dose of IN ketamine in individuals with major depressive disorder (MDD) or bipolar depression (BDep), both with and without comorbid alcohol use disorder (AUD).

METHODS

Twenty-eight individuals with primary diagnoses of MDD or BDep I/II currently experiencing a depressive episode with active suicidality were enrolled; approximately 60 % had comorbid AUD. Changes in the NIH-Brief Fatigue Inventory (NIH-BFI) were assessed at baseline and at 4, 24, and 48 h post-treatment.

RESULTS

The group x time interaction for NIH-BFI score was significant (F = 3.44, p = 0.022), favoring IN ketamine over placebo. IN ketamine was well-tolerated with minimal adverse effects.

LIMITATIONS

Limitations include the limited sample size, short duration, and single, fixed dose.

CONCLUSIONS

IN ketamine appears to induce rapid anti-fatigue effects in individuals with severe MDD and BDep both with and without comorbid AUD. This suggests that IN ketamine holds potential as an alternative, rapid-acting, anti-fatigue option for different medical conditions.

Lithium, the gold standard drug for bipolar disorder: analysis of current clinical studies

Lithium is the gold standard drug in the treatment of bipolar disorder. Despite increasing scientific interest, relatively few patients with bipolar disorder receive lithium therapy. Lithium is the only drug that is effective in the prophylaxis of manic, depressive, and suicidal symptoms. Lithium therapy is also associated with a variety of adverse drug reactions and the need for therapeutic drug monitoring. Numerous studies have focussed on the efficacy and safety of both lithium-monotherapy and lithium-add-on therapy. The aim of this study is to provide a systematic overview of clinical studies on lithium therapy for bipolar disorder from the last 7 years and to present a critical analysis of these studies. The results provide an up-to-date overview of the efficacy, tolerability, and safety of lithium therapy for bipolar disorder and thus improve the pharmacotherapy of bipolar disorder. A total of 59 studies were analysed using various analysis parameters. The studies were also categorised into different subgroups. These are lithium-monotherapy, lithium vs. placebo/drug, and lithium + adjunctive therapy. The majority of the studies (N = 20) had a duration of only 3-8 weeks. Only 13 studies lasted for > 40 weeks. Lithium was superior to aripiprazole, valproic acid, and quetiapine in terms of improving manic symptoms. Lithium therapy resulted in a lower relapse rate compared to valproic acid therapy. Lithium was more neuroprotectively effective than quetiapine. Fourteen of the 22 add-on therapies to lithium showed a predominantly positive effect on the treatment outcome compared to lithium-monotherapy. Only the add-on therapy with sertraline led to a higher rate of study discontinuations than lithium-monotherapy. Lithium is a safe and effective treatment option for children. However, risperidone and quetiapine were superior to lithium in some aspects, which is why these drugs should be considered as an alternative treatment option for children. Collectively, current clinical studies highlight the relevance of lithium in the treatment of bipolar disorder.

A computational model to characterize the time-course of response to rapid antidepressant therapies

Our objective is to propose a method capable of disentangling the magnitude, the speed, and the duration or decay rate of the time course of response to rapid antidepressant therapies. To this end, we introduce a computational model of the time course of response to a single treatment with a rapid antidepressant. Numerical simulation is used to evaluate whether model parameters can be accurately estimated from observed data. Finally, we compare our computational modelling-based approach with linear mixed effects modelling in terms of their ability to detect changes in the magnitude and time-course of response to rapid antidepressant therapies in simulated randomized trials. Simulation experiments show that the parameters of our computational model can be accurately recovered using nonlinear least squares. Parameter estimation accuracy is stable over noise levels reaching as high as 25% of the true antidepressant effect magnitude. Comparison of our approach to mixed effects modelling using simulated randomized controlled trial data demonstrates an inability of linear mixed models to disentangle effect magnitude and time course, while our computational model accurately separates these response components. Our modelling approach may accurately identify the (A) magnitude, (B) speed, and (C) durability or decay rate of response to rapid antidepressant therapies. Future studies should fit this model to data from real clinical trials, and use resulting parameter estimates to uncover predictors and causes of different elements of the temporal course of antidepressant response.

Short-term ketamine use in bipolar depression: a review of the evidence for short-term treatment management

Bipolar depression constitutes a major problem in psychiatry. It correlates with high suicidality, treatment resistance, chronicity, and poor quality of life. Registered treatment for bipolar depression is limited and insufficient. There is an urgent need for implementing new therapeutic strategies. Intranasal ketamine's enantiomer-esketamine is a novel rapid-acting antidepressant with proven efficacy in treatment-resistant depression. Research on bipolar depression, although not as comprehensive, indicates that it may be a viable and safe substitute with minimal risk for mood polarity changes. Reports suggest that ketamine treatment in bipolar depression may reduce suicidal tendencies, decrease anhedonia, and alleviate anxiety. Ketamine's mood-stabilizing properties are also hypothesized. In this narrative review, we focus on ketamine use as an add-on to standard medication for the acute treatment of bipolar depression.

The Role of Ketamine in the Treatment of Bipolar Depression: A Scoping Review

Bipolar depression remains a clinical challenge with a quarter of patients failing to respond to initial conventional treatments. Although ketamine has been extensively studied in unipolar depression, its role in bipolar disorder remains inconclusive. The aim of our scoping review was to comprehensively synthesize the current clinical literature around ketamine use in bipolar depression. A total of 10 clinical studies (5 randomized controlled trials and 5 open label studies) were selected. The preliminary evidence, albeit weak, suggests that ketamine is a promising treatment and calls for further interest from the research community. Overall, ketamine treatment appeared to be tolerable with minimal risk for manic/hypomanic switching and showed some effectiveness across parameters of depression and suicidality. Moreover, ketamine is a potential treatment agent in patients with treatment-resistant bipolar depression with promising data extracted from extant controlled trials and real-world effectiveness studies. Future studies are needed to identify ketamine's role in acute and maintenance treatment phases of bipolar depression. Moreover, future researchers should study the recurrence prevention and anti-suicidal effects of ketamine in the treatment of bipolar depression.

Antifatigue effect of sea buckthorn seed oil on swimming fatigue in mice

The effect of sea buckthorn seed oil (SSO) on exercise-induced fatigue in mice was explored. The animals were randomly divided into a normal control group, exercise-induced fatigue group (EFG), SSO low-dose group, SSO medium-dose group, and SSO high-dose group. The mice in all the groups underwent swimming training for 10 days. Those in the treatment groups received different amounts of SSO (0.85, 1.68, and 3.35 g/kg BW [body weight]) before the exercise. All the animals were sacrificed on the last day after an exhaustive swimming test, and serum, liver, and brain specimens were collected. In the exhaustive swimming test, the swimming durations in the SSO-treated animals were longer than those in the EFG. Furthermore, SSO reduced serum lactic acid, blood urea nitrogen, and hepatic malondialdehyde levels and increased liver glycogen level, hepatic superoxide dismutase level, hypothalamic dopamine content, and glutathione peroxidase level. The SSO treatment decreased hypothalamic 5-hydroxytryptamine content, lipid hydroperoxide level, NLRP3 inflammasome, and interleukin-1β protein expression in the prefrontal cortex. Furthermore, it promoted the protein expression of nuclear factor erythroid 2-related factor 2 in the liver. SSO exhibited an excellent antifatigue effect, which may be related to its inhibition of oxidative and inflammatory injury and regulation of hypothalamic neurotransmitters. PRACTICAL APPLICATION: In the present study, the effect of sea buckthorn seed oil on fatigue in mice and its potential mechanism were explored. Taken together, the findings provide insight into the potential role of sea buckthorn seed oil in the development of antifatigue drugs.

Low-dose ketamine infusion for the treatment of multiple sclerosis fatigue (INKLING-MS): Study protocol for a randomized, double-blind, active placebo-controlled phase II trial

BACKGROUND

Fatigue is one of the most common symptoms of people with Multiple Sclerosis (MS). However, currently-used medications for the treatment of fatigue probably do not work better than a placebo. In a pilot trial, we showed that one infusion of low-dose ketamine significantly improved fatigue severity measured four weeks after the infusion.

METHODS

The proposed study is a single-center, phase II, randomized, double-blind, parallel-group, active-placebo-controlled trial of intravenous low-dose ketamine in patients with MS fatigue. Participants will be randomized 1:1:1 into three groups: receiving either one or two infusions of ketamine (0.5 mg/kg over 40 min) or zero to one infusion of the active placebo (midazolam, 0.05 mg/kg over 40 min). Eligibility criteria include adult patients diagnosed with MS based on the latest criteria, complaining of fatigue as one of the main symptoms, and having a screening MFIS score higher than a pre-specified threshold.

RESULTS

One hundred and ten participants will be randomized over 30 months at Johns Hopkins MS Center. Complete enrollment is expected by mid-2025. The study's primary outcome will be the MFIS score at the end of week 4, comparing two-thirds of the participants who received ketamine with one-third who received midazolam. The secondary and exploratory outcomes (measured four weeks after the second infusion) will show how long the effects of a single infusion last and if two infusions of ketamine are better than one in improving MS fatigue.

CONCLUSION

This study can show whether intervening in the glutamatergic pathways would improves MS fatigue.

Brain mapping inflammatory-arthritis-related fatigue in the pursuit of novel therapeutics

Despite developments in pharmacological treatments, chronic fatigue is an unresolved issue for most people with inflammatory arthritis that severely disrupts their personal and working lives. Fatigue in these patients is not strongly linked with peripheral disease activity but is associated with CNS-derived symptoms such as chronic pain, sleep disturbance, and depression. Therefore, a neurobiological basis should be considered when pursuing novel fatigue-specific therapeutics. In this Review, we focus on clinical imaging biomarkers that map candidate brain regions and are crucial in fatigue pathophysiology. We then evaluate neuromodulation techniques that could affect these candidate brain regions and are potential treatment strategies for fatigue in patients with inflammatory arthritis. We delineate work that is still required for neuroimaging and neuromodulation to eventually become part of a clinical pathway to treat and manage fatigue.

A Concept Development for the Symptom Science Model 2.0

BACKGROUND

The National Institute of Nursing Research developed the National Institutes of Health symptom science model (SSM) in 2015 as a parsimonious conceptual model to guide symptom science research.

OBJECTIVES

This concept development paper synthesizes justifications to strengthen the original model.

METHODS

A literature review was performed, discussions with symptom science content expert stakeholders were held, and opportunities for expanding the current model were identified. Concept elements for a revised conceptual model-the SSM 2.0-were developed.

RESULTS

In addition to the four original concept elements (complex symptom presentation, phenotypic characterization, biobehavioral factors [previously biomarker discovery], and clinical applications), three new concept elements are proposed, including social determinants of health, patient-centered experience, and policy/population health.

DISCUSSION

There have been several calls to revise the original SSM from the nursing scientific community to expand its utility to other healthcare settings. Incorporating three additional concept elements can facilitate a broader variety of translational nursing research symptom science collaborations and applications, support additional scientific domains for symptom science activities, and produce more translatable symptom science to a wider audience of nursing research scholars and stakeholders during recovery from the COVID-19 pandemic. The revised SSM 2.0 with newly incorporated social determinants of health, patient-centered experience, and policy/population health components now empowers nursing scientists and scholars to address specific symptom science public health challenges particularly faced by vulnerable and underserved populations.

Effect of a single sub-dose of ketamine on postoperative fatigue syndrome in colorectal cancer patients undergoing radical laparoscopic surgery: A double-blind, pilot study

BACKGROUND

This study aimed at examining the effect of a single sub-anesthetic dose of ketamine on postoperative fatigue syndrome (POFS) in patients undergoing radical laparoscopic surgery for colorectal cancer (CRC).

METHODS

This prospective, double-blind, pilot study enrolled patients scheduled for radical laparoscopic surgery for CRC under general anesthesia. Eligible patients were randomized into the placebo and ketamine groups. The primary outcome was christensen score change at day 3. The secondary outcomes were the difference of Identity Consequence Fatigue Scale (ICFS) score between the placebo group and ketamine group at day 3 and level of serum tumor necrosis factor (TNF)-α, interleukin (IL)-6, S100β protein, and neuron-specific enolase (NSE).

RESULTS

32 participants were assigned to the ketamine group and 31 to the placebo group. Compared with placebo group, the Christensen score was lower in ketamine group at day 3 (absolute difference, -1.13; 95 % confidence interval [CI], -2.02 to -0.24; P = 0.012). Ketamine group was superior to the placebo group with regard to the ICFS scores at day 3 (absolute difference, -6.4; 95 % CI, -11.4 to -1.4; P = 0.013). The plasma TNF-α, IL-6, S100β, and NSE levels were increased after operation compared with baseline in both groups and were significantly higher in placebo group than in ketamine group within 24 h after surgery (all P < 0.05). There was no significant difference of each safety evaluation indicator between the two groups (all P > 0.05).

CONCLUSION

A single sub-anesthetic dose of ketamine may improve POFS in patients undergoing radical laparoscopic surgery for CRC, without postoperative adverse reactions.

A Narrative Review on Axonal Neuroprotection in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) resulting in demyelination and neurodegeneration. The therapeutic strategy is now largely based on reducing inflammation with immunosuppressive drugs. Unfortunately, when disease progression is observed, no drug offers neuroprotection apart from its anti-inflammatory effect. In this review, we explore current knowledge on the assessment of neurodegeneration in MS and look at putative targets that might prove useful in protecting the axon from degeneration. Among them, Bruton's tyrosine kinase inhibitors, anti-apoptotic and antioxidant agents, sex hormones, statins, channel blockers, growth factors, and molecules preventing glutamate excitotoxicity have already been studied. Some of them have reached phase III clinical trials and carry a great message of hope for our patients with MS.

Treatment-Resistant Bipolar Depression: Therapeutic Trends, Challenges and Future Directions

INTRODUCTION

Bipolar disorder (BD) is a chronic mental illness impacting 1-2% of the population worldwide and causing high rates of functional impairment. Patients with BD spend most of their time in depressive episodes and up to one-third of patients do not respond to adequate doses of medications. Although no consensus exists for definition of treatment-resistant bipolar depression (TRBD), failure of symptoms improvement despite an adequate trial of two therapeutic agents is a common theme of TRBD. In this paper, we review the evidence base of therapeutic interventions, challenges, and potential future directions for TRBD.

METHODS

We conducted a literature search for randomized controlled trials on PubMed for the treatment of TRBD and ongoing trials for the treatment of TRBD/bipolar depression on clinicaltrials.gov.

RESULTS

Several therapeutic agents have been investigated for TRBD. Adjunctive pramipexole and modafinil have data supporting short-term efficacy in TRBD, along with limited data for racemic intravenous ketamine. Celecoxib augmentation of escitalopram and treatment with metformin in patients with insulin resistance showed promising results. Right unilateral electroconvulsive therapy displayed statistically significant response rate and improvement, but not remission compared to pharmacotherapy. Trials for transcranial magnetic stimulation (TMS) have failed to show a significant difference from sham treatment in TRBD.

FUTURE TRENDS

Pharmacological treatments with novel mechanisms of actions like brexpiprazole and vortioxetine are being investigated following successes in unipolar depression. Modified TMS protocols such as accelerated TMS are under investigation. Innovative approaches like psychedelic-assisted psychotherapy, interleukin-2, fecal microbiota transplantation and multipotent stromal cells are being studied.

CONCLUSION

Evidence on current treatment modalities for TRBD is limited with low efficacy. More research is needed for successful treatment of TRBD. Effective therapies and innovative approaches to treatment are being investigated and could show promise.

The potential pro-cognitive effects with intravenous subanesthetic ketamine in adults with treatment-resistant major depressive or bipolar disorders and suicidality

BACKGROUND

Ketamine has rapid and robust antidepressant effects in depression, while its effects on cognitive measures are less clearly understood. This aim of the study herein is to determine whether ketamine has direct pro-cognitive effects in real-world treatment depression and/or suicidality.

METHODS

Subjects with unipolar (n = 84) and bipolar (n = 27) depression suffering treatment resistance or suicidality received six infusions of ketamine (0.5 mg/kg) during a 12-day period. Depression symptoms were assessed using the Montgomery-Asberg Depression Rating Scale at baseline, day 13 and day 26. Cognitive domains, including processing speed, working memory, visual learning and verbal learning were also measured using the MATRICS Consensus Cognitive Battery at the same time-points.

RESULTS

Significant improvement was observed in processing speed at day 13 (effect size [ES] = 0.501) and day 26 (ES = 0.654), and verbal learning at day 13 (ES = 0.362). Path analysis showed significant direct (β = 2.444, P = 0.017) and indirect (β = 1.220, P = 0.048) effect of ketamine on processing speed, indicating its improvement was partly independent of improvement in depressive symptoms. The direct effect (β = -1.963, P = 0.052) of ketamine on verbal learning was not significant, whereas the indirect effect (β = 1.386, P = 0.024) was significant, indicating treatment with ketamine indirectly improved verbal learning performance, via changes in depressive symptom.

CONCLUSION

Six infusions of ketamine have a potential mood independent pro-cognitive effect on processing speed in adults with treatment depression and/or suicidality. The potential pro-cognitive effects of ketamine provide the basis for hypothesizing that other clinical outcomes (e.g., suicidality, functional impairment) reported with ketamine treatment may be in part mediated by improvement in cognition.

Advances in the psychopharmacotherapy of bipolar disorder type I

INTRODUCTION

Research into the pharmacologic management of bipolar type I illness continues to progress.

AREAS COVERED

Randomized clinical trials performed with type I bipolar disorder in the years 2015 to August 2020 are reviewed. There are new indications for the use of cariprazine, for bipolar mania and depression, and a long-acting injectable formulation of aripiprazole has also been approved for relapse prevention in bipolar illness. Most of the randomized clinical trials are effectiveness studies.

EXPERT OPINION

Over the 20 years from 1997 through 2016, the use of lithium and other mood stabilizers has declined by 50%, while the use of both second-generation antipsychotics (SGAs) and antidepressants has increased considerably. Over the same time period (1990-2017), disability-adjusted life years (DALYs) increased by 54.4%, from 6.02 million in 1990 to 9.29 million in 2017 which is greater than the 47.74% increase in incidence of the disease, suggesting that the changes in prescribing patterns have not been helpful for our patients. Furthermore, recent effectiveness studies continue to confirm the superiority of lithium and other mood stabilizers in the management of bipolar illness for both psychiatric and medical outcomes, reaffirming their role as foundational treatments in the management of type I bipolar disorder. Clinicians need to reassess their prescribing habits.

Pharmacological Treatment of Bipolar Depression: What are the Current and Emerging Options?

Depression accounts for the predominant burden associated with bipolar disorder. The identification and management of bipolar depression are challenging, since bipolar depression differs from unipolar depression, responding poorly to traditional antidepressants, which may also induce a switch to hypomania/mania, mixed states and/or cause rapid cycling. Current treatment options for bipolar depression are limited and guidelines vary greatly in their recommendations, reflecting gaps and inconsistencies in the current evidence base. Moreover, some treatment options, such as quetiapine and olanzapine-fluoxetine, although clearly efficacious, may be associated with adverse cardiometabolic side effects, which can be detrimental to the long-term physical health and well-being of patients, increasing the likelihood of treatment non-adherence and relapse. Evidence for some more recent therapeutic options, including lurasidone and cariprazine, suggests that patients' symptoms can be effectively managed without compromising their physical health. In addition, novel agents targeting alternative neurotransmitter pathways and inflammatory processes (such as ketamine and N-acetyl cysteine) are emerging as promising potential options for the treatment of bipolar depression in the future.

The CINP Guidelines on the Definition and Evidence-Based Interventions for Treatment-Resistant Bipolar Disorder

BACKGROUND

Resistant bipolar disorder is a major mental health problem related to significant disability and overall cost. The aim of the current study was to perform a systematic review of the literature concerning (1) the definition of treatment resistance in bipolar disorder, (2) its clinical and (3) neurobiological correlates, and (4) the evidence-based treatment options for treatment-resistant bipolar disorder and for eventually developing guidelines for the treatment of this condition.

MATERIALS AND METHODS

The PRISMA method was used to identify all published papers relevant to the definition of treatment resistance in bipolar disorder and the associated evidence-based treatment options. The MEDLINE was searched to April 22, 2018.

RESULTS

Criteria were developed for the identification of resistance in bipolar disorder concerning all phases. The search of the literature identified all published studies concerning treatment options. The data were classified according to strength, and separate guidelines regarding resistant acute mania, acute bipolar depression, and the maintenance phase were developed.

DISCUSSION

The definition of resistance in bipolar disorder is by itself difficult due to the complexity of the clinical picture, course, and treatment options. The current guidelines are the first, to our knowledge, developed specifically for the treatment of resistant bipolar disorder patients, and they also include an operationalized definition of treatment resistance. They were based on a thorough and deep search of the literature and utilize as much as possible an evidence-based approach.

Moxibustion at 'Danzhong' (RN17) and 'Guanyuan' (RN4) for fatigue symptom in patients with depression: Study protocol clinical trial (SPIRIT Compliant)

BACKGROUND

Fatigue is one of the most prevalent and debilitating symptoms of major depressive disorder (MDD). The effective management of depression-related fatigue has an important impact on the patient's abilities, functioning, and quality of life (QOL). Moxibustion has been widely used in Traditional Chinese Medicine to manage fatigue. Recent studies have also demonstrated that moxibustion is effective for treating cancer-related fatigue and chronic fatigue syndrome. However, there is not sufficient data supporting the effect of moxibustion for depression-related fatigue. Therefore, this randomized, assessor-blinded, wait-list controlled trial is designed to evaluate the effectiveness, safety, and feasibility of moxibustion treatment for depression-related fatigue.

METHODS

One hundred and seventy-six participants who meet the diagnostic criteria for depression in the International Classification of Diseases, tenth revision (ICD-10), and who also have a score of ≥1 on the 13 item of the Hamilton Depression Rating Scale-17 (HAMD-17), will be enrolled. At study entry, participants will undergo anti-depressant treatment for at least 1 month. Then those who still have a score of ≥1 on the 13 item of the HAMD-17 will be randomly allocated to either a moxibustion group or wait-list control group in a ratio of 1:1. Anti-depressants will be provided for both groups during the whole process of the study period. Participants in the moxibustion group will undergo 14 sessions of moxibustion (over 2 weeks) with anti-depressant treatment, and participants in the wait-list control group will receive only anti-depressant treatment. Subsequently, participants in the moxibustion group will be followed-up for 4 weeks. The primary outcome measure will be the Fatigue Severity Scale (FSS). The secondary outcome measure will be the HAMD-17. Safety will be assessed by monitoring adverse events during the study. Trial feasibility will also be assessed in this study.

DISCUSSION

The results of this study may provide evidence for the efficacy of moxibustion as an adjunct to antidepressants for depression-related fatigue, and promote a more widespread foundation for the selection of moxibustion in the clinical setting as well as for future research in moxibustion therapy.

TRIAL REGISTRATION

This study protocol was registered at the Chinese Clinical Trial Registry (ChiCTR1800016905).

The influence of ketamine on drug discovery in depression

Recent research demonstrating that the glutamatergic modulator ketamine has rapid, robust, and sustained antidepressant effects has been a turning point in drug discovery for depression. The recent FDA approval of esketamine for adults with treatment-resistant major depressive disorder (MDD) has further underscored the relevance of this agent in spurring investigation into novel and mechanistically distinct agents for use in depression. Over the past two decades, ketamine research has ushered in a new wave of studies seeking to not only identify its mechanism of action but also to examine the antidepressant potential of novel or repurposed agents. This article reviews the approaches that have proven particularly fruitful for the field of neuropsychiatry.

Glutamatergic Modulators in Depression

LEARNING OBJECTIVE

After participating in this activity, learners should be better able to evaluate the evidence supporting the antidepressant effects of glutamatergic modulators.Both preclinical and clinical studies have implicated glutamatergic system dysfunction in the pathophysiology of mood disorders such as bipolar depression and major depressive disorder. In particular, rapid reductions in depressive symptoms have been noted in response to subanesthetic doses of the glutamatergic modulator ketamine in subjects with major depressive disorder or bipolar depression. These results have prompted the repurposing or development of other glutamatergic modulators, both as monotherapy or adjunctive to other therapies. Here, we highlight the evidence supporting the antidepressant effects of various glutamatergic modulators, including (1) broad glutamatergic modulators (ketamine, esketamine, dextromethorphan, dextromethorphan-quinidine [Nuedexta], AVP-786, nitrous oxide [N2O], AZD6765), (2) subunit (NR2B)-specific N-methyl-D-aspartate (NMDA) receptor antagonists (CP-101,606/traxoprodil, MK-0657 [CERC-301]), (3) glycine-site partial agonists (D-cycloserine, GLYX-13, sarcosine, AV-101), and (4) metabotropic glutamate receptor modulators (AZD2066, RO4917523/basimglurant, JNJ40411813/ADX71149, R04995819 [RG1578]).

Using human experience to identify drug repurposing opportunities: theory and practice

Retrospective evidence drawn from real-world experience of a medicine's use outside its labelled indication is one of a number of techniques used in drug repurposing (DRP). Relying as it does on large numbers of real incidences of human experience, rather than individual case reports with limited statistical support, preclinical experiments with poor translatability or in silico associations, which are early-stage hypotheses, it represents the best validated form of DRP. Cancer is the most frequent of such DRP examples (e.g. aspirin in pancreatic cancer, hazard ratio = 0.25). This approach can be combined with pathway analysis to provide first-in-class treatments for complex diseases. Alternatively, it can be combined with prospective preclinical studies to uncover a validated mechanism for a new indication, after which a repurposed molecule is chemically optimized.

Glutamatergic Neurotransmission: Pathway to Developing Novel Rapid-Acting Antidepressant Treatments

The underlying neurobiological basis of major depressive disorder remains elusive due to the severity, complexity, and heterogeneity of the disorder. While the traditional monoaminergic hypothesis has largely fallen short in its ability to provide a complete picture of major depressive disorder, emerging preclinical and clinical findings suggest that dysfunctional glutamatergic neurotransmission may underlie the pathophysiology of both major depressive disorder and bipolar depression. In particular, recent studies showing that a single intravenous infusion of the glutamatergic modulator ketamine elicits fast-acting, robust, and relatively sustained antidepressant, antisuicidal, and antianhedonic effects in individuals with treatment-resistant depression have prompted tremendous interest in understanding the mechanisms responsible for ketamine's clinical efficacy. These results, coupled with new evidence of the mechanistic processes underlying ketamine's effects, have led to inventive ways of investigating, repurposing, and expanding research into novel glutamate-based therapeutic targets with superior antidepressant effects but devoid of dissociative side effects. Ketamine's targets include noncompetitive N-methyl-D-aspartate receptor inhibition, α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid throughput potentiation coupled with downstream signaling changes, and N-methyl-D-aspartate receptor targets localized on gamma-aminobutyric acid-ergic interneurons. Here, we review ketamine and other potentially novel glutamate-based treatments for treatment-resistant depression, including N-methyl-D-aspartate receptor antagonists, glycine binding site ligands, metabotropic glutamate receptor modulators, and other glutamatergic modulators. Both the putative mechanisms of action of these agents and clinically relevant studies are described.

Disentangling the association of depression on the anti-fatigue effects of ketamine

BACKGROUND

Fatigue and depression are closely associated. The purpose of this secondary analysis was to understand the relationships between depression and improvements in specific depression domains on the anti-fatigue effects of ketamine, which we previously reported.

METHODS

This secondary analysis re-evaluated data collected longitudinally from 39 patients with treatment-resistant Major Depressive Disorder (MDD) enrolled in a double-blind, randomized, placebo-controlled, crossover trial using a single intravenous infusion of ketamine hydrochloride (0.5 mg/kg over 40 minutes) or placebo. A mediation model assessed the effect of depression on the anti-fatigue effects of a single dose of intravenous ketamine versus placebo at Day 1 post-infusion. Fatigue was measured using the National Institutes of Health-Brief Fatigue Inventory (NIH-BFI), and depression was assessed by the Montgomery-Ǻsberg Depression Rating Scale (MADRS).

RESULTS

Compared to placebo, ketamine significantly improved fatigue (p = .0003) as measured by the NIH-BFI, but the anti-fatigue effects of ketamine disappeared (p = .47) when controlling for depression as measured by MADRS total score. In this study sample, the anti-fatigue effects of ketamine were mostly accounted for by the changes in amotivation and depressed mood scores.

CONCLUSIONS

In this study, ketamine did not have a unique effect on fatigue outside of its general antidepressant effects in patients with treatment-resistant depression. Specifically, the anti-fatigue effects of ketamine observed in this study seem to be explained by the effects of ketamine on two symptom domains of depression: amotivation and depressed mood. The study findings suggest that the anti-fatigue effects of ketamine should be assessed by fatigue-specific measures other than the NIH-BFI or future studies should enroll fatigued patients without depression.

A predictive algorithm to identify genes that discriminate individuals with fibromyalgia syndrome diagnosis from healthy controls

Objectives

Fibromyalgia syndrome (FMS) is a chronic and often debilitating condition that is characterized by persistent fatigue, pain, bowel abnormalities, and sleep disturbances. Currently, there are no definitive prognostic or diagnostic biomarkers for FMS. This study attempted to utilize a novel predictive algorithm to identify a group of genes whose differential expression discriminated individuals with FMS diagnosis from healthy controls.

Methods

Secondary analysis of gene expression data from 28 women with FMS and 19 age-and race-matched healthy women. Expression of discriminatory genes were identified using fold-change differential and Fisher’s ratio (FR). Discriminatory accuracy of the differential expression of these genes was determined using leave-one-out-cross-validation. Functional networks of the discriminating genes were described from the Ingenuity’s Knowledge Base.

Results

The small-scale signature contained 57 genes whose expressions were highly discriminatory of the FMS diagnosis. The combination of these high discriminatory genes with FR higher than 1.45 provided a leave-one-out-cross-validation accuracy for the FMS diagnosis of 85.11%. The discriminatory genes were associated with 3 canonical pathways: hepatic stellate cell activation, oxidative phosphorylation, and airway pathology related to COPD.

Conclusion

The discriminating genes, especially the 2 with the highest accuracy, are associated with mitochondrial function or oxidative phosphorylation and glutamate signaling. Further validation of the clinical utility of this finding is warranted.

Collaborative Framework to Advance Symptom Science: An Intramural Perspective

PURPOSE

To describe the collaborative framework used by National Institute of Nursing Research (NINR) investigators to advance symptom science and to provide a research exemplar.

MODEL

The National Institutes of Health (NIH) Symptom Science Model (SSM) was developed to guide symptom science researchers to understand the molecular underpinnings of symptoms using innovative "omics" approaches. The process begins with a review of the literature to understand the state of the science of the symptoms of interest and is followed by cross-sectional, case-controlled, or longitudinal studies to identify potential biological correlates of these symptoms. The final steps include validation of these potential symptom biomarkers using multidisciplinary, collaborative, preclinical experiments, and proof-of-concept clinical trials.

RESEARCH EXEMPLAR

Using the NIH SSM as a guide, the identification of biologic correlates of symptoms using omics and bioinformatic strategies depends on determining the distinct phenotype of the symptoms of interest. The identified biologic correlates of these symptoms are then validated for their functional relevance using in vitro and ex vivo experiments, or through proof-of-concept clinical trials. NINR investigators observed that activation of specific receptors in neural networks can trigger inflammation-related fatigue development and predispose patients to develop chronicity of symptoms. Specifically targeting these neural receptors can reduce symptom intensity.

CONCLUSIONS

Through using the NIH SSM as a guide, NINR investigators quickly generate data and discoveries that significantly advance symptom science by simultaneously collaborating with multiple experts and core laboratories to identify more correlates and validate their functional relevance in order to further understand the biological underpinnings of the symptoms of interest.

CLINICAL RELEVANCE

The collaborative framework used by NINR investigators as guided by the NIH SSM identifies functionally relevant clinical markers that can explain the biological underpinnings of symptoms and can be targeted to optimize symptom management.

Rapid effectiveness of intravenous ketamine for ultraresistant depression in a clinical setting and evidence for baseline anhedonia and bipolarity as clinical predictors of effectiveness

BACKGROUND

Intravenous ketamine has been established as an efficacious and safe treatment, with transient effect, for treatment-resistant depression. However, the effectiveness of intravenous ketamine in non-research settings and with ultraresistant depression patients remains understudied.

AIMS

This study aims to measure the response and remission rates in ultraresistant depression patients in a clinical setting by means of a retrospective, open label, database study. Secondarily, the study will attempt to support previous findings of clinical predictors of effectiveness with intravenous ketamine treatment.

METHODS

Fifty patients with ultraresistant depression were treated between May 2015-December 2016, inclusive, in two community hospitals in Edmonton using six ketamine infusions of 0.5 mg/kg over 40 min over 2-3 weeks. Data were collected retrospectively from inpatient and outpatient charts. Statistical analysis to investigate clinical predictors of effectiveness included logistic regression analysis using a dependent variable of a 50% reduction in rating scale score at any point during treatment.

RESULTS

At baseline, the average treatment resistance was severe, with a Maudsley Staging Method score of 12.1 out of 15, 90.0% were resistant to electroconvulsive therapy, and the average Beck Depression Inventory score was 34.2. The response rate was 44% and remission rate was 16%. As a single predictor, moderate or severe anhedonia at baseline predicted a 55% increased likelihood of response. As a combined predictor, this level of anhedonia at baseline with a diagnosis of bipolar depression predicted a 73% increase in likelihood of response.

CONCLUSION

In a clinical setting, intravenous ketamine showed effectiveness in a complex, severely treatment-resistant, depressed population on multiple medication profiles concurrently. This study gave support to anhedonia and bipolar depression as clinical predictors of effectiveness.

Anti-exercise-fatigue and promotion of sexual interest activity of total flavonoids from wasps drone-pupae in male mice

The aim of this research was to evaluate the anti-exercise-fatigue and promotion of sexual interest of total flavonoids from drone pupae of wasps. DPTF was prepared by ethanol extracting and its extraction conditions were optimized by response surface methodology. Then, anti-exercise-fatigue and promotion of sexual interest of DPTF were evaluated. The optimums extraction conditions by RSM were ethanol concentration 65%, extraction time 3 h and solid-to-liquid 20:1(mL/g). No mortality and general symptoms of toxicity were observed in the DPTF treated mice(1 g/kg,3 g/kg,5 g/kg body weight) the body weight and food consumption were not significantly changed compared with the normal control group. The relative weights of main organ did not markedly change. DPTF can significantly extend the duration of the swimming time to exhaustion and the times of capture the female in mice, decrease BUN, LAC and Cr levels, increase LG, GG and T activities in the DPTF treated mice. The dose of 5 g/kg body weight is the optimal dose for anti-exercise-fatigue activity and promotion of sexual interest in male mice. In conclusion, DPTF is promising traditional natural-based therapeutic remedy for relieving exercise-fatigue with high safety.

Dose-Related Effects of Adjunctive Ketamine in Taiwanese Patients with Treatment-Resistant Depression

The antidepressant effects of ketamine are thought to depend on brain-derived neurotrophic factor (BDNF) genotype and dose. The purpose of this study was to characterize the dose-related antidepressant effects of ketamine in patients with treatment-resistant depression drawn from a Chinese population predominately possessing lower activity BDNF genotypes (Val/Met, Met/Met). We conducted a double-blind, randomized, parallel-group, placebo-controlled trial of a single ketamine infusion (saline, 0.2 mg/kg, 0.5 mg/kg). Patients (N=71; BDNF genotype: Val/Val (N=12, 17%), Val/Met (N=40, 56.3%), and Met/Met (N=19, 26.8%)) received mood ratings before infusion, after infusion, and for the subsequent 14 days. Plasma ketamine levels and BDNF genotypes were assessed. This study found a significant dose-related ketamine effect on scores on the Hamilton Depression Rating Scale (HAMD). The responder analysis (>50% reduction from baseline HAMD on at least 2 days between days 2 and 5) also revealed a significant dose-related effect (saline: 12.5%, 0.2 mg/kg: 39.1%; 0.5 mg/kg: 45.8%). This is the first report to our knowledge to demonstrate the dose-related efficacy of R/S-ketamine for treatment-resistant depression and the first to characterize ketamine effects in a genotyped Chinese population in which most (83%) patients possessed at least one copy of the lower functioning Met allele of the BDNF gene.

Anti-fatigue activity of sea cucumber peptides prepared from Stichopus japonicus in an endurance swimming rat model

BACKGROUND

Sea cucumber (Stichopus japonicus) is a well-known nutritious and luxurious seafood in Asia which has attracted increasing attention because of its nutrition and bioactivities in recent years. In this study, the anti-fatigue activity of sea cucumber peptides (SCP) prepared from S. japonicus was evaluated in a load-induced endurance swimming model.

RESULTS

The SCP prepared in this study was mainly made up of low-molecular-weight peptides (<2 kDa). The analysis result of amino acid composition revealed that SCP was rich in glycine, glutamic acid and proline. The endurance capability of rats to fatigue was significantly improved by SCP treatment. Meanwhile, the remarkable alterations of energy metabolic markers, antioxidant enzymes, antioxidant capacity and oxidative stress biomarkers were normalized. Moreover, administration of SCP could modulate alterations of inflammatory cytokines and downregulate the overexpression of TRL4 and NF-κB.

CONCLUSION

SCP has anti-fatigue activity and it exerted its anti-fatigue effect probably through normalizing energy metabolism as well as alleviating oxidative damage and inflammatory responses. © 2017 Society of Chemical Industry.

Targeting glutamate signalling in depression: progress and prospects

Major depressive disorder (MDD) is severely disabling, and current treatments have limited efficacy. The glutamate N-methyl-D-aspartate receptor (NMDAR) antagonist ketamine was recently repurposed as a rapidly acting antidepressant, catalysing the vigorous investigation of glutamate-signalling modulators as novel therapeutic agents for depressive disorders. In this Review, we discuss the progress made in the development of such modulators for the treatment of depression, and examine recent preclinical and translational studies that have investigated the mechanisms of action of glutamate-targeting antidepressants. Fundamental questions remain regarding the future prospects of this line of drug development, including questions concerning safety and tolerability, efficacy, dose-response relationships and therapeutic mechanisms.

Symptomatology and predictors of antidepressant efficacy in extended responders to a single ketamine infusion

BACKGROUND

Antidepressant response to a single subanesthetic dose infusion of the glutamatergic modulator ketamine is transient in most depressed patients; however, a minority continue to experience an extended response. This study examined depressive symptoms and potential clinical predictors of extended response to ketamine in subjects with mood disorders.

METHODS

Subjects were diagnosed with either major depressive disorder (MDD) or bipolar depression. All subjects were treatment-resistant and experiencing a major depressive episode of at least moderate severity. MDD subjects were unmedicated and those with bipolar depression were receiving therapeutic-dose lithium or valproate. All subjects received a single 0.5mg/kg ketamine infusion. Data were collected pre-infusion (baseline) and at days one, 14, and 28 post-infusion.

RESULTS

Twelve of 93 (12.9%) participants continued to meet response criteria (50% reduction in Montgomery-Asberg Depression Rating Scale (MADRS) score) at two weeks. All depressive symptoms assessed by the MADRS were improved at two weeks in ketamine responders except for sleep duration/depth. A positive family history of alcohol use disorder in a first-degree relative (FHP) and greater dissociation during the infusion were associated with better antidepressant response at two weeks. Improved measures of apparent sadness, reported sadness, inability to feel, and difficulty concentrating at day 1 correlated most strongly with antidepressant effects at two weeks.

LIMITATIONS

Post-hoc design, small sample size, diagnostic heterogeneity.

CONCLUSIONS

Static (FHP) and dynamic (improved depressive symptoms) factors may be clinically useful in predicting whether a patient will have an extended response to ketamine.