Antidepressant effects of total iridoids of Valeriana jatamansi via the intestinal flora-blood-brain barrier pathway

CONTEXT

Valeriana jatamansi Jones [syn. V. wallichii DC, (Valerianaceae)] (VJJ) is used to treat depression.

OBJECTIVE

To explore the effects of total iridoids of VJJ extract (TIV) on chronic unpredictable mild stress (CUMS) in mice.

MATERIALS AND METHODS

VJJ roots and rhizomes were extracted with 70% ethanol. CUMS rats were treated daily with fluoxetine (2.6 mg/kg, i.g.) or TIV (5.7, 11.4, and 22.8 mg/kg, i.g.) for 14 days. Male Kun Ming mice on normal chow and 0.5% CMC-Na solution were used as a control. Behavioural tests included the tail suspension (TST) and sucrose preference tests (SPT). Evans blue staining was used to evaluate blood-brain barrier (BBB) permeability. Western blotting was used to measure zonula occludens-1 (ZO-1) and occludin expression. 16S rRNA sequencing was used to analyse intestinal flora abundance. Tax4Fun was used to predict KEGG metabolic pathways.

RESULTS

TIV treatment reduced TST time (117.35 ± 8.23 or 108.95 ± 6.76 vs. 144.45 ± 10.30 s), increased SPT (55.83 ± 7.24 or 53.12 ± 13.85 vs. 38.98 ± 5.43%), increased the abundance of phylum Firmicutes (86.99 ± 0.03 vs. 60.88 ± 0.19%) and genus Lactobacillus (75.20 ± 0.19 vs. 62.10 ± 0.13%), reduced the abundance of phylum Bacteroidetes (6.69 ± 0.06 or 11.50 ± 0.09 vs. 25.07 ± 0.20%). TIV increased carbohydrate metabolism (14.50 ± 3.00 × 10-3 or 14.60 ± 2.00 × 10-3 or 14.90 ± 2.00 × 10-3 vs.13.80 ± 4.00 × 10-3%), replication and repair functions (5.60 ± 1.00 × 10-3 or 5.60 ± 1.00 × 10-3 vs. 5.10 ± 4.00 × 10-3%), reduced the frequency of infectious disease (1.60 ± 2.00 × 10-4 or 1.90 ± 5.00 × 10-4 or 1.80 ± 3.00 × 10-4 vs. 2.20 ± 7.00 × 10-3%), BBB permeability (0.77 ± 0.30 vs. 1.81 ± 0.33 μg/g), and up-regulated the expression of ZO-1 (1.42-fold, 1.60-fold, 1.71-fold) and occludin (1.79-fold, 2.20-fold).

CONCLUSIONS

TIV may modulate the intestinal flora, thereby inducing the expression of ZO-1 and occludin, protecting the BBB and exerting an antidepressant effect.

Phencynonate hydrochloride exerts antidepressant effects by regulating the dendritic spine density and altering glutamate receptor expression

Phencynonate hydrochloride (PCH) is a drug that crosses the blood-brain barrier. Cellular experiments confirmed that PCH protects against glutamate toxicity and causes only weak central inhibition and limited side effects. As shown in our previous studies, PCH alleviates depression-like behaviours induced by chronic unpredictable mild stress (CUMS). Here we administered PCH at three different doses (4, 8 and 16 mg/kg) to male rats for two continuous days after CUMS and conducted behavioural tests to assess the dose-dependent antidepressant effects of PCH and its effects on the neuroplasticity in the hippocampus and medial prefrontal cortex (mPFC). Meanwhile, we measured the spine density and expression of related proteins to illustrate the mechanism of PCH. PCH treatment (8 mg/kg) significantly alleviated depression-like behaviours induced by CUMS. All doses of PCH treatment reversed the spine loss in prelimbic and CA3 regions induced by CUMS. Kalirin-7 expression was decreased in the hippocampus and mPFC of the CUMS group. The expression of the NR1 and NR2B subunits in the hippocampus, and NR2B in mPFC are increased by CUMS. PCH treatment (8 and 16 mg/kg) reversed all of these changes of Kalirin-7 in PFC and hippocampus, as well as NR1 and NR2B expression in the hippocampus. PCH is expected to be developed as a new type of rapid antidepressant. Its antidepressant effect may be closely related to the modulation of dendritic spine density in the prelimbic and CA3 regions and the regulation of Kalilin-7 and N-methyl-D-aspartic acid receptor levels in the hippocampus.

The anti-depressant effects of a novel PDE4 inhibitor derived from resveratrol

CONTEXT

Resveratrol has shown anti-stress and anti-depressant-like abilities involved in inhibiting phosphodiesterase-4 (PDE4) enzyme. However, its application is limited due to its low efficacy, bioavailability and selectivity.

OBJECTIVE

This study synthesized a new resveratrol derivative RES003 and evaluated its PDE4 inhibitory and anti-depressant-like activities in vitro and in vivo, respectively.

MATERIALS AND METHODS

PDEs inhibitory activities were evaluated by radioactive tracer method. Anti-depressant-like activities of novel resveratrol analogue (RES003) at doses of 2.5, 5.0 and 10 mg/kg was investigated by sugar water consumption and forced swimming tests using male ICR mice under chronic unpredictable stress procedure for 10 days. A total of 84 mice were randomly distributed into seven groups (n = 12). Drugs and vehicle were administered (intra-gastric or intra-peritoneal) once a day from the first to the last day. The molecular mechanisms were identified by western blot.

RESULTS

RES003 showed more potent PDE4 inhibitory activity (half maximal inhibitory concentration (IC₅₀), 0.87 μM) and better selectivity than resveratrol (IC₅₀, 18.8 μM). RES003 could significantly increase the consumption of sugar water (p < 0.01) and immobility time (p < 0.01) compared to vehicle-treated stressed groups at doses of 5 and 10 mg/kg. Furthermore, RES003 could significantly increase the levels of cyclic adenosine monophosphate response element binding protein phosphorylation (10 mg/kg, p < 0.05) and brain-derived neurotrophic factor (BDNF) expression (5 and 10 mg/kg, p < 0.05 and 0.01) in mouse brain.

DISCUSSION AND CONCLUSIONS

RES003 could ameliorate chronic stress induced depression-like behaviours through inhibition of PDE4 and activation of cAMP-triggered phosphorylation of cAMP response element binding protein/BDNF signalling pathway. Consequently, RES003 is a promising lead compound for the treatment of depression.

Associations Between Antidepressant Use and Advanced Diabetes Outcomes in Patients with Depression and Diabetes Mellitus

CONTEXT

Comorbid depression in patients with diabetes deteriorates the prognosis. Antidepressants might attenuate the adverse effects of depression; however, they are associated with cardiometabolic adverse effects.

OBJECTIVE

This study aimed to explore the association between antidepressant treatment and advanced diabetic complications and mortality among patients with depression and diabetes mellitus.

METHODS

We conducted a nationwide retrospective cohort study of 36 276 patients with depression and newly treated diabetes mellitus using Taiwan's universal health insurance database. Antidepressant treatment patterns within a 6-month window were classified into none, poor, partial, and regular use, and we accounted for time-dependent variables in the Cox proportional hazards regression analysis with adjustment for time-dependent comorbidity and concomitant use of medications. Different classes of antidepressants were compared. Macro- and microvascular complications, as well as all-cause mortality, were the main outcomes. Benzodiazepines were chosen as negative control exposure.

RESULTS

Compared with poor use of antidepressants, regular use was associated with a 0.92-fold decreased risk of macrovascular complications and a 0.86-fold decreased risk of all-cause mortality but not associated with microvascular complications. Regular use of selective serotonin reuptake inhibitors was associated with a 0.83- and 0.75-fold decreased risk of macrovascular complications and all-cause mortality, respectively. Regular use of tricyclic or tetracyclic antidepressants was associated with a 0.78-fold decreased risk of all-cause mortality. Regular use of benzodiazepine showed no association with diabetic outcomes.

CONCLUSION

Regular antidepressant use was associated with lower risk of advanced diabetic complications compared with poor adherence. Clinicians should emphasize antidepressant treatment adherence among patients with depression and diabetes mellitus.

Dose-dependent opposite effects of nortriptyline on affective-like behavior in adolescent rats: Comparison with adult rats

Antidepressant drugs elicit different behavioral and neurochemical responses with age. In fact, the use of antidepressants during adolescence is associated with an increased risk of suicidal thinking, being the best pharmacological treatment during this critical period a matter of constant debate in terms of its risk-benefit outcome. In this regard, the present study compared the effects of nortriptyline (3-10 mg/kg, 7 days) on regulating different aspects of affective-like behavior by screening adolescent and adult Sprague-Dawley rats through several consecutive tests (forced-swim, open field, sucrose preference). Brains were later collected to evaluate hippocampal neurogenesis and mBDNF protein content as potential molecular correlates of the observed behavioral responses. The main results in adolescent rats showed that nortriptyline induced dose-dependent opposite effects: while 3 mg/kg decreased immobility and increased mBDNF (indicative of an antidepressant-like response), 10 mg/kg decreased exploratory time in the open field and mBDNF (suggestive of an anxiogenic-like response). These effects were not associated with changes in neurogenesis regulation. In adult rats, nortriptyline failed to modulate affective-like behavior or the neuroplasticity markers evaluated at the doses tested. In conclusion, clear behavioral and neurochemical differences were observed between adolescent and adult rats in response to nortriptyline treatment. Interestingly, while nortriptyline displayed an antidepressant-like potential at the lowest dose examined in adolescence, a higher dose shifted these results towards a negative outcome, thus reinforcing the need to extreme caution when considering this treatment for our younger population.

Clinical efficacy of Danzhi Xiaoyao Powder in the treatment of post-stroke depression: A protocol for randomized, double-blind clinical study

BACKGROUND

Depression is a common complication after stroke and is closely related to the poor prognosis of stroke. Antidepressants are the priority drug in the treatment of post-stroke depression (PSD), but there are dependence and adverse reactions. Danzhi Xiaoyao Powder has a good effect on depression without obvious adverse reactions. At present, there is a lack of rigorous randomized controlled trials to evaluate the clinical efficacy of Danzhi Xiaoyao Powder in the treatment of PSD.

METHODS

This is a prospective, randomized, double-blind, parallel controlled trial to explore the efficacy and safety of Danzhi Xiaoyao Powder in the treatment of PSD. The participants were randomly divided into treatment group and control group. The treatment group used Danzhi Xiaoyao Powder combined with escitalopram oxalate, and the control group used Danzhi Xiaoyao Powder simulant combined with citalopram oxalate. The two groups were both treated for 8 weeks and followed up for 3 months. Observational index includes: Total response rate, Hamilton depression scale, Barthel index, national institutes of health stroke scale, the modified Edinburgh-Scandinavian stroke scale, Incidence of adverse reactions. Finally, SPASS 22.0 software was used for statistical analysis of the data.

DISCUSSION

This study will evaluate the clinical efficacy of Danzhi Xiaoyao Powder in the treatment of PSD. The results of this study will provide reliable evidence for the clinical use of Xiaoyao Powder in the treatment of PSD.

TRIAL REGISTRATION

Open Science Framework Registration number: DOI 10.17605/OSF.IO/5V926.

Is the Preoperative Use of Antidepressants and Benzodiazepines Associated with Opioid and Other Analgesic Use After Hip and Knee Arthroplasty?

BACKGROUND

Mental health disorders can occur in patients with pain conditions, and there have been reports of an increased risk of persistent pain after THA and TKA among patients who have psychological distress. Persistent pain may result in the prolonged consumption of opioids and other analgesics, which may expose patients to adverse drug events and narcotic habituation or addiction. However, the degree to which preoperative use of antidepressants or benzodiazepines is associated with prolonged analgesic use after surgery is not well quantified.

QUESTION/PURPOSES

(1) Is the preoperative use of antidepressants or benzodiazepine medications associated with a greater postoperative use of opioids, NSAIDs, or acetaminophen? (2) Is the proportion of patients still using opioid analgesics 1 year after arthroplasty higher among patients who were taking antidepressants or benzodiazepine medications before surgery, after controlling for relevant confounding variables? (3) Does analgesic drug use decrease after surgery in patients with a history of antidepressant or benzodiazepine use? (4) Does the proportion of patients using antidepressants or benzodiazepines change after joint arthroplasty compared with before?

METHODS

Of the 10,138 patients who underwent hip arthroplasty and the 9930 patients who underwent knee arthroplasty at Coxa Hospital for Joint Replacement, Tampere, Finland, between 2002 and 2013, those who had primary joint arthroplasty for primary osteoarthritis (64% [6502 of 10,138] of patients with hip surgery and 82% [8099 of 9930] who had knee surgery) were considered potentially eligible. After exclusion of another 8% (845 of 10,138) and 13% (1308 of 9930) of patients because they had revision or another joint arthroplasty within 2 years of the index surgery, 56% (5657 of 10,138) of patients with hip arthroplasty and 68% (6791 of 9930) of patients with knee arthroplasty were included in this retrospective registry study. Patients who filled prescriptions for antidepressants or benzodiazepines were identified from a nationwide drug prescription register, and information on the filled prescriptions for opioids (mild and strong), NSAIDs, and acetaminophen were extracted from the same database. For the analyses, subgroups were created according to the status of benzodiazepine and antidepressant use during the 6 months before surgery. First, the proportions of patients who used opioids and any analgesics (that is, opioids, NSAIDs, or acetaminophen) were calculated. Then, multivariable logistic regression adjusted with age, gender, joint, Charlson Comorbidity Index, BMI, laterality (unilateral/same-day bilateral), and preoperative analgesic use was performed to calculate odds ratios for any analgesic use and opioid use 1 year postoperatively. Additionally, the proportion of patients who used antidepressants and benzodiazepines was calculated for 2 years before and 2 years after surgery.

RESULTS

At 1 year postoperatively, patients with a history of antidepressant or benzodiazepine use were more likely to fill prescriptions for any analgesics than were patients without a history of antidepressant or benzodiazepine use (adjusted odds ratios 1.9 [95% confidence interval 1.6 to 2.2]; p < 0.001 and 1.8 [95% CI 1.6 to 2.0]; p < 0.001, respectively). Similarly, patients with a history of antidepressant or benzodiazepine use were more likely to fill prescriptions for opioids than patients without a history of antidepressant or benzodiazepine use (adjusted ORs 2.1 [95% CI 1.7 to 2.7]; p < 0.001 and 2.0 [95% CI 1.6 to 2.4]; p < 0.001, respectively). Nevertheless, the proportion of patients who filled any analgesic prescription was smaller 1 year after surgery than preoperatively in patients with a history of antidepressant (42% [439 of 1038] versus 55% [568 of 1038]; p < 0.001) and/or benzodiazepine use (40% [801 of 2008] versus 55% [1098 of 2008]; p < 0.001). The proportion of patients who used antidepressants and/or benzodiazepines was essentially stable during the observation period.

CONCLUSION

Surgeons should be aware of the increased risk of prolonged opioid and other analgesic use after surgery among patients who were on preoperative antidepressant and/or benzodiazepine therapy, and they should have candid discussions with patients referred for elective joint arthroplasty about this possibility. Further studies are needed to identify the most effective methods to reduce prolonged postoperative opioid use among these patients.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Antidepressant and anxiolytic compounds isolated from Salvia elegans interact with serotonergic drugs

Salvia elegans belongs to a genus plants with biological activities in central nervous system. In this work, the purpose was to evaluate the anxiolytic and antidepressant effects of fractions and compounds isolated from S. elegans and its interaction with serotoninergic drugs by using behavioral tests in mice. Fractions from aerial parts of S. elegans were obtained by column chromatography, SeF1, SeF2, SeF3, and SeF4. Each of them was administered to 25 mg/k in ICR mice subject to forced swimming test (FST), or elevated plus maze test (EPM), or open field test (OFT). The most active fractions were chemically separated until compounds, which were analyzed as anxiolytic or antidepressant and the coadministration of these treatments with 5-HT_1A and 5-HT₂ drugs was measured in the different biological tests. All fractions were anxiolytic and antidepressant, oleanolic acid (OA) was found in SeF2, and from SeF3, a mixture of terpenes was found; a GC-MS analysis confirmed the presence of two main compounds: rosifoliol and agaraspirol (TM, mixture of terpenes). TM (doses-response curve, 0.01, 0.1, 0.5, 1.0, and 2.0 mg/kg) and OA (5 mg/kg) were also evaluated demonstrating an antidepressant and anxiolytic effect, respectively. The combination of TM (0.5 mg/kg) with 8-OH (selective 5-HT_1A receptor agonist) induced an increment of antidepressant activity, while with the antagonist WAY-100635, the effect diminished. But with DOI (5-HT₁c/5-HT₂ receptor agonist), there was no change, and with KET (5-HT₂ receptor antagonist), the activity was increased. When OA is co-administered with 8-OH or with DOI, the anxiolytic activity of this terpene, diminished; but with the combination with antagonists, the effect of OA shows no change. TM and OA were antidepressant and anxiolytic, respectively, on mice exposed to different tests, and these are able to interact with serotoninergic drugs.

Esketamine Nasal Spray for the Rapid Reduction of Depressive Symptoms in Major Depressive Disorder With Acute Suicidal Ideation or Behavior

PURPOSE/BACKGROUND

Numerous health authority approvals of esketamine nasal spray, combined with oral antidepressant, to treat depressive symptoms in adults with major depressive disorder and acute suicidal ideation or behavior were based on 2 identically designed, double-blind, phase 3 studies.

METHODS/PROCEDURES

Across both ASPIRE studies (NCT03039192, NCT03097133), patients (N = 456) were randomized to esketamine 84 mg or placebo nasal spray twice weekly for 4 weeks plus comprehensive standard of care, including hospitalization and newly initiated or optimized antidepressant(s). In post hoc analyses of pooled data, changes from baseline at 24 hours after the first dose in Montgomery-Åsberg Depression Rating Scale total score and Clinical Global Impression-Severity of Suicidality-Revised, in the full cohort and in subgroups, were analyzed using analysis of covariance.

FINDINGS/RESULTS

Esketamine plus standard of care demonstrated significantly greater improvement in Montgomery-Åsberg Depression Rating Scale total score versus placebo plus standard of care at 24 hours (least square mean difference [95% confidence interval], -3.8 [-5.75 to -1.89]) and at earlier (4 hours: -3.4 [-5.05 to -1.71]) and later time points (day 25: -3.4 [-5.36 to -1.36]). The between-group difference (95% confidence interval) for change in Clinical Global Impression-Severity of Suicidality-Revised at 24 hours was -0.20 (-0.43 to 0.04) for all patients and -0.31 (-0.61 to -0.01) for those with a history of suicide attempt. Common adverse events (≥20%) during esketamine treatment were dizziness, dissociation, nausea, somnolence, and headache.

IMPLICATIONS/CONCLUSIONS

Esketamine plus comprehensive standard of care rapidly reduces depressive symptoms in patients with major depressive disorder who have acute suicidal ideation or behavior, especially in those with a history of suicide attempt, providing a new treatment option for this particularly ill and vulnerable population.

A comparison of the pharmacokinetics and NMDAR antagonism-associated neurotoxicity of ketamine, (2R,6R)-hydroxynorketamine and MK-801

With the increasing use of ketamine as an off-label treatment for depression and the recent FDA approval of (S)-ketamine for treatment-resistant depression, there is an increased need to understand the long-term safety profile of chronic ketamine administration. Of particular concern is the neurotoxicity previously observed in rat models following acute exposure to high doses of ketamine, broadly referred to as 'Olney's lesions'. This type of toxicity presents as abnormal neuronal cellular vacuolization, followed by neuronal death and has been associated with ketamine's inhibition of the N-methyl-d-aspartate receptor (NMDAR). In this study, a pharmacological and neuropathological analysis of ketamine, the potent NMDAR antagonist MK-801, and the ketamine metabolite (2R,6R)-hydroxynorketamine [(2R,6R)-HNK)] in rats is described following both single dose and repeat dose drug exposures. Ketamine dosing was studied up to 20 mg/kg intravenously for the single-dose neuropathology study and up to 60 mg/kg intraperitoneally for the multiple-dose neuropathology study. MK-801 dosing was studied up to 0.8 mg/kg subcutaneously for both the single and multiple-dose neuropathology studies, while (2R,6R)-HNK dosing was studied up to 160 mg/kg intravenously in both studies. These studies confirm dose-dependent induction of 'Olney's lesions' following both single dose and repeat dosing of MK-801. Ketamine exposure, while showing common behavioral effects, did not induce wide-spread Olney's lesions. Treatment with (2R,6R)-HNK did not produce behavioral effects, toxicity or any evidence of Olney's lesion formation. Based on these results, future NMDAR-antagonist neurotoxicity studies should strongly consider taking pharmacokinetics more thoroughly into account.

Long-Term Efficacy of Intranasal Esketamine in Treatment-Resistant Major Depression: A Systematic Review

Esketamine (ESK) has been approved as a rapid-acting intranasal treatment for treatment-resistant depression (TRD). Although existing studies have investigated the efficacy of ESK in the 4-week induction phase, our knowledge about long-term ESK efficacy remains poor. The aim of this systematic review was to summarize the available data on long-term ESK efficacy for TRD. A systematic search was performed including articles in English, up to 31 March 2021. The search found 7 relevant studies, involving 1024 adult TRD patients. Continuing treatment with ESK after the 4-week induction phase may be associated with stable efficacy in relapse prevention among TRD patients. Conversely, the long-term antidepressant effectiveness upon discontinuation of ESK might be limited, although data from three studies had a moderate to high risk of bias. Overall, the results on the effectiveness of this compound in the long term are mixed. According to our findings, ESK treatment should be continued following the induction phase to reach a stable efficacy in relapse prevention, while the long-term antidepressant and anti-suicidal effects of ESK after discontinuation are inconsistent. Currently, the level of proof of ESK efficacy in long-term TRD treatment remains low and more RCTs with larger sample sizes and active comparators are needed.

The selective 5-HT1A receptor biased agonists, F15599 and F13714, show antidepressant-like properties after a single administration in the mouse model of unpredictable chronic mild stress

RATIONALE

The prevalence of depression is ever-increasing throughout the population. However, available treatments are ineffective in around one-third of patients and there is a need for more effective and safer drugs.

OBJECTIVES

The antidepressant-like and procognitive effects of the "biased agonists" F15599 (also known as NLX-101) which preferentially targets postsynaptic 5-HT1A receptors and F13714, which targets 5-HT1A autoreceptors, were investigated in mice.

METHODS

Antidepressant-like properties of the compounds and their effect on cognitive functions were assessed using the forced swim test (FST) and the novel object recognition (NOR), respectively. Next, we induced a depressive-like state by an unpredictable chronic mild stress (UCMS) procedure to test the compounds' activity in the depression model, followed by measures of sucrose preference, FST, and locomotor activity. Levels of phosphorylated cyclic AMP response element-binding protein (p-CREB) and phosphorylated extracellular signal-regulated kinase (p-ERK1/2) were also determined.

RESULTS

F15599 reduced immobility time in the FST over a wider dose-range (2 to 16 mg/kg po) than F13714 (2 and 4 mg/kg po), suggesting accentuated antidepressant-like properties in mice. F15599 did not disrupt long-term memory consolidation in the NOR at any dose tested, while F13714 impaired memory formation, notably at higher doses (4-16 mg/kg). In UCMS mice, a single administration of F15599 and F13714 was sufficient to robustly normalize depressive-like behavior in the FST but did not rescue disrupted sucrose preference. Both F15599 and F13714 rescued cortical and hippocampal deficits in p-ERK1/2 levels of UCMS mice but did not influence the p-CREB levels.

CONCLUSIONS

Our studies showed that 5-HT1A receptor biased agonists such as F13714 and especially F15599, due to its less pronounced side effects, might have potential as fast-acting antidepressants.

CKD-506: A novel HDAC6-selective inhibitor that exerts therapeutic effects in a rodent model of multiple sclerosis

Despite advances in therapeutic strategies for multiple sclerosis (MS), the therapy options remain limited with various adverse effects. Here, the therapeutic potential of CKD-506, a novel HDAC6-selective inhibitor, against MS was evaluated in mice with myelin oligodendrocyte glycoprotein35-55 (MOG35-55)-induced experimental autoimmune encephalitis (EAE) under various treatment regimens. CKD-506 exerted prophylactic and therapeutic effects by regulating peripheral immune responses and maintaining blood-brain barrier (BBB) integrity. In MOG35-55-re-stimulated splenocytes, CKD-506 decreased proliferation and downregulated the expression of IFN-γ and IL-17A. CKD-506 downregulated the levels of pro-inflammatory cytokines in the blood of EAE mice. Additionally, CKD-506 decreased the leakage of intravenously administered Evans blue into the spinal cord; CD4+ T cells and CD4-CD11b+CD45+ macrophage/microglia in the spinal cord was also decreased. Moreover, CKD-506 exhibited therapeutic efficacy against MS, even when drug administration was discontinued from day 15 post-EAE induction. Disease exacerbation was not observed when fingolimod was changed to CKD-506 from day 15 post-EAE induction. CKD-506 alleviated depression-like behavior at the pre-symptomatic stage of EAE. In conclusion, CKD-506 exerts therapeutic effects by regulating T cell- and macrophage-mediated peripheral immune responses and strengthening BBB integrity. Our results suggest that CKD-506 is a potential therapeutic agent for MS.

Approach to the Patient with Chronic Pruritus

Chronic pruritus (itch lasting ≥6 weeks) is a bothersome chief complaint that may present in a broad variety of diseases. Most itch-causing diagnoses fit into 1 of 5 categories (inflammatory, secondary to systemic disease, neuropathic, chronic pruritus of undetermined origin, and psychogenic itch) and this broad differential can be narrowed using key findings in the history and physical. In this article, we discuss which key findings are most pertinent for narrowing this differential and guiding further workup and treatment, as well as how to treat many itchy conditions.

Co-administration of cannabidiol and ketamine induces antidepressant-like effects devoid of hyperlocomotor side-effects

BACKGROUND AND PURPOSE

Although useful as a rapid-acting antidepressant drug, ketamine is known to induce psychotomimetic effects, which may interfere with its therapeutic use. Cannabidiol (CBD) is a non-psychostimulant compound from Cannabis sativa, which has shown promising antidepressant effects without inducing hyperlocomotion. AMPA receptor activation is involved in the antidepressant effect induced by ketamine, but its relevance for the effects of CBD is not known. Moreover, given that CBD has antipsychotic and antidepressant properties, it is unknown whether adding CBD to ketamine could potentiate the antidepressant properties of ketamine while also attenuating its psychostimulant effects.

EXPERIMENTAL APPROACH

S-Ketamine (2.5, 3, 5, 10, 30 mg/kg) and cannabidiol (3, 10, 30 mg/kg) were administered alone or in combination to male Swiss mice. Independent groups received NBQX (AMPA receptor antagonist) 5 min before administration of CBD or S-ketamine. The antidepressant-like effect was assessed in the forced swimming test (FST), and the open field test (OFT) evaluated the psychostimulant effect.

KEY RESULTS

CBD induced significant dose-dependent antidepressant effects without causing hyperlocomotion in the OFT. S-ketamine produced an antidepressant effect associated with hyperlocomotion in the higher dose. NBQX inhibited the antidepressant effect of both ketamine and CBD. Pretreatment with CBD (10 mg/kg) attenuated the ketamine-induced hyperlocomotion while preserving its antidepressant effect.

CONCLUSION

AND IMPLICATIONS: Similar to ketamine, the antidepressant-like effect elicited by CBD involves AMPA receptor activation. Additionally, CBD prevents the hyperlocomotion induced by S-ketamine without affecting its antidepressant-like effect. Our findings suggest that CBD and ketamine's combined administration can be a promising therapeutic strategy for achieving an appropriate antidepressant effect without unwanted side-effects. This article is part of the special issue on 'Cannabinoids'.

Bupropion for postpartum smoking relapse: A remote protocol for a two-arm, double-blind, placebo-controlled randomized clinical trial

Cigarette smoking among postpartum women remains a significant public health problem despite known health risks to women and their newborns. It is estimated that over 50% of women quit smoking during pregnancy but 90% relapse by one year. Safe and effective postpartum relapse prevention strategies are urgently needed. In an attempt to address this deficit, we will investigate the efficacy of bupropion vs. placebo as a smoking relapse prevention aid in postpartum women. The objective of this paper is to detail an approach to investigate bupropion's efficacy for preventing postpartum smoking relapse among women who quit smoking during pregnancy. Specifically, we designed a two-arm, double-blind, placebo-controlled randomized trial testing the efficacy of bupropion vs. placebo as a relapse prevention tool. Mothers of healthy infants who quit smoking while pregnant will be stratified based on current or past history of major depressive disorder or persistent depressive disorder and randomized to receive either active (bupropion XL 300 mg/day) or placebo medication for 12 weeks. To respond to safety concerns associated with participant and staff exposure to COVID-19, we revised our original protocol and present procedures which allow our trial to be conducted entirely remotely. Primary and secondary outcomes will be assessed at weeks 12, 24, 36 and 52 post-randomization. The primary outcome is 7-day point prevalence abstinence at 24 weeks. Results of this work have the potential to positively impact women and their children by promoting lifelong cessation, eliminating secondhand smoke exposure, and modelling of abstinence to children.

Ketamine-50 years in use: from anesthesia to rapid antidepressant effects and neurobiological mechanisms

Over the past 50 years, ketamine has solidified its position in both human and veterinary medicine as an important anesthetic with many uses. More recently, ketamine has been studied and used for several new indications, ranging from chronic pain to drug addiction and post-traumatic stress disorder. The discovery of the rapid-acting antidepressant effects of ketamine has resulted in a surge of interest towards understanding the precise mechanisms driving its effects. Indeed, ketamine may have had the largest impact for advancements in the research and treatment of psychiatric disorders in the past few decades. While intense research efforts have been aimed towards uncovering the molecular targets underlying ketamine's effects in treating depression, the underlying neurobiological mechanisms remain elusive. These efforts are made more difficult by ketamine's complex dose-dependent effects on molecular mechanisms, multiple pharmacologically active metabolites, and a mechanism of action associated with the facilitation of synaptic plasticity. This review aims to provide a brief overview of the different uses of ketamine, with an emphasis on examining ketamine's rapid antidepressant effects spanning molecular, cellular, and network levels. Another focus of the review is to offer a perspective on studies related to the different doses of ketamine used in antidepressant research. Finally, the review discusses some of the latest hypotheses concerning ketamine's action.

Vorinostat (SAHA) May Exert Its Antidepressant-Like Effects Through the Modulation of Oxidative Stress Pathways

Suberoylanilide hydroxamic acid (SAHA/Vorinostat), a potent inhibitor of histone deacetylases (HDACs), is known to possess antidepressant properties. However, the exact mechanisms underlying this activity are unknown. In this study, we evaluated the effect of SAHA on the expression of GluN2A, GluN2B (NMDA receptor subunits), (p-)AMPK, and ΔFos proteins which are an integral part of the signal transduction pathways in the brain and also involved in the pathophysiology of depression as well as the mechanism of antidepressant action. We also measured the concentration of malondialdehyde (MDA - a product of lipid peroxidation). The study was carried out in the prefrontal cortex (PFC) and hippocampus (Hp), brain regions implicated in depression. Although SAHA induced changes in the expression of all the proteins and MDA concentration, the effects differed depending on the drug dose, time, and brain structure involved. SAHA reduced MDA concentration and significantly increased p-AMPK protein expression, indicating it may prevent oxidative stress. SAHA also increased the levels of HDAC3 and NMDA subunits (GluN2A and GluN2B), implying it is neuroprotective and may play a crucial role in synaptic plasticity. Moreover, ΔFosB and FosB levels were significantly elevated, suggesting that SAHA may modulate learning and memory processes. Overall, the data indicate that the Hp might play a pivotal role in the mechanism of action of SAHA, hinting at novel mechanisms it play in the antidepressant and neuroprotective effects of SAHA.

Rapid-acting and long-lasting antidepressant-like action of (R)-ketamine in Nrf2 knock-out mice: a role of TrkB signaling

The transcription nuclear factor-erythroid factor 2-related factor 2 (Nrf2) plays a key role in inflammation that is involved in depression. We previously reported that Nrf2 knock-out (KO) mice exhibit depression-like phenotypes through systemic inflammation. (R)-ketamine, an enantiomer of ketamine, has rapid-acting and long-lasting antidepressant-like effects in rodents. We investigated whether (R)-ketamine can produce antidepressant-like effects in Nrf2 KO mice. Effects of (R)-ketamine on the depression-like phenotypes in Nrf2 KO mice were examined. Furthermore, the role of TrkB in the antidepressant-like actions of (R)-ketamine was also examined. In the tail-suspension test (TST) and forced swimming test (FST), (R)-ketamine (10 mg/kg) significantly attenuated the increased immobility times of TST and FST in the Nrf2 KO mice. In the sucrose preference test (SPT), (R)-ketamine significantly ameliorated the reduced preference of SPT in Nrf2 KO mice. Decreased expression of synaptic proteins (i.e., GluA1 and PSD-95) in the medial prefrontal cortex (mPFC) of Nrf2 KO mice was significantly ameliorated after a single injection of (R)-ketamine. Furthermore, the pre-treatment with the TrkB antagonist ANA-12 (0.5 mg/kg) significantly blocked the rapid and long-lasting antidepressant-like effects of (R)-ketamine in Nrf2 KO mice. Furthermore, ANA-12 significantly antagonized the beneficial effects of (R)-ketamine on decreased expression of synaptic proteins in the mPFC of Nrf2 KO mice. These findings suggest that (R)-ketamine can produce rapid and long-lasting antidepressant-like actions in Nrf2 KO mice via TrkB signaling.

Inflammatory cytokines derived from peripheral blood contribute to the modified electroconvulsive therapy-induced cognitive deficits in major depressive disorder

Little is known about the pathophysiology of memory deficits in patients with major depressive disorder (MDD) treated with modified electroconvulsive therapy (MECT). This study examined the profiles of cytokines, the memory function, and their association in MECT-treated MDD patients. Forty first-episode, drug-free MDD patients and 40 healthy controls were recruited. MECT was started with antidepressant treatment at a stable initial dose. The Wechsler Memory Scale (WMS) and Hamilton Rating Scale for Depression 17 (HRSD-17) were used to assess the cognitive function. MDD patients were divided into the memory impairment group (WMS < 50) and the non-memory impairment group (WMS ≥ 50) based on the total WMS scores after MECT. The levels of NOD-like receptor 3 (NLRP3) inflammasome, interleukin-18 (IL-18) and nuclear factor kappa-B (NF-κB) in the serum were measured. MDD patients showed significantly higher levels of NLRP3 inflammasome, IL-18 and NF-κB than that in the controls prior to MECT, and the levels also significantly increased after MECT. In MDD patients, the serum levels of these inflammatory cytokines were negatively associated with the total WMS scores and likely contributed to the scores independently. The receiver operating characteristic curve showed that the serum levels of these inflammatory cytokines may predict the cognitive impairment risk in MDD patients receiving MECT. Abnormal levels of NLRP3 inflammasome, IL-18 and NF-κB reflecting the disturbed balance of pro-inflammatory and anti-inflammatory mechanisms likely contribute to the MECT-induced cognitive deficits in MDD patients.

Saffron Extract-Induced Improvement of Depressive-Like Behavior in Mice Is Associated with Modulation of Monoaminergic Neurotransmission

Depressive disorders represent a major public health concern and display a continuously rising prevalence. Importantly, a large proportion of patients develops aversive side effects and/or does not respond properly to conventional antidepressants. These issues highlight the need to identify further therapeutic strategies, including nutritional approaches using natural plant extracts with known beneficial impacts on health. In that context, growing evidence suggests that saffron could be a particularly promising candidate. This preclinical study aimed therefore to test its antidepressant-like properties in mice and to decipher the underlying mechanisms by focusing on monoaminergic neurotransmission, due to its strong implication in mood disorders. For this purpose, the behavioral and neurobiochemical impact of a saffron extract, Safr’Inside™ (6.5 mg/kg per os) was measured in naïve mice. Saffron extract reduced depressive-like behavior in the forced swim test. This behavioral improvement was associated with neurobiological modifications, particularly changes in serotonergic and dopaminergic neurotransmission, suggesting that Safr’Inside™ may share common targets with conventional pharmacological antidepressants. This study provides useful information on the therapeutic relevance of nutritional interventions with saffron extracts to improve management of mood disorders.

Early symptomatic improvements as a predictor of response to repeated-dose intravenous ketamine: Results from the Canadian Rapid Treatment Center of Excellence

BACKGROUND

Early symptomatic improvement with monoamine-based antidepressants is predictive of treatment response. The objective of this study was to determine if early symptomatic improvements with intravenous (IV) ketamine predicted treatment response to an acute course of four infusions.

METHOD

134 adults with treatment resistant depression (TRD) received four ketamine infusions over one to two weeks. Depressive symptoms were measured using the Quick Inventory for Depressive Symptomatology Self-Report₁₆ (QIDS-SR₁₆) at baseline and post-infusions 1, 2, 3, and 4. Early improvement was defined as ≥20% reduction in QIDS-SR₁₆ scores after the first or second infusion. Linear models were used to determine whether early improvement was associated with post-infusion 4 QIDS-SR₁₆ scores after controlling for baseline characteristics.

RESULTS

Early improvement post-infusion 1 (β = -3.52, 95% BCa CI [-5.40, -1.78]) and 2 (β = -3.16, 95% BCa CI [-5.75, -1.59]) both significantly predicted QIDS-SR₁₆ scores post-infusion 4. Early improvers had significantly lower QIDS-SR₁₆ scores at post-infusion 4 (post-infusion 1 improvers: M = 9.8, SD = 4.5; post-infusion 2 improvers: M = 10.6, SD = 5.7) compared to non-early improvers (post-infusion 1 non-improvers: M = 13.7, SD = 5.8; post-infusion 2 non-improvers: M = 14.1, SD = 5.3) when controlling for baseline characteristics. The majority (58%) of individuals who did not improve post-infusions 1 or 2 still experienced an antidepressant response or partial response (≥20% reduction in QIDS-SR₁₆) post-infusion 4.

LIMITATIONS

This is a post-hoc analysis of an open-label study.

CONCLUSION

Early improvement was associated with greater antidepressant effects following a course of four ketamine infusions. However, individuals who did not show early improvements still had a high likelihood of experiencing clinically significant symptom reduction after the fourth infusion, suggesting that completing four infusions, regardless of early symptom changes, is appropriate and merited.

Consistency of the Antidepressant Effect of Intranasal Esketamine in Phase 3 Clinical Trials

This column reviews the development of intranasal esketamine with particular emphasis on the consistency of the clinical trial results. In the process, it illustrates methodological issues important in the approval process by an agency such as the United States Food and Drug Administration. Topics covered include the importance of study design, the nature of the comparator, and the prespecified statistical analysis plan. The column also discusses what is considered a positive versus a supportive study and the differences between phase 2 and phase 3 studies and the rationale for including both in the development process. While this information is particularly germane to intranasal esketamine, it also serves as a more general example of the drug development and approval process.

Psychiatric Medication Changes Associated With Increased Rate of Medical Readmissions in Patients With Serious Mental Illness

ABSTRACT

To identify the impact of postdischarge psychiatric medication changes on general medical readmissions among patients with serious mental illness (SMI; bipolar disorder, major depressive disorder, and schizophrenia), claims from a 5% national sample of Medicare fee-for-service (FFS) beneficiaries hospitalized between 2013 and 2016 were studied. A total of 165,490 Medicare FFS beneficiaries with SMI 18 years or older with at least 1 year of continuous Medicare enrollment were identified. Within 30 days of discharge from index admission, 47.4% experienced a psychiatric medication change-including 75,892 beneficiaries experiencing a deletion and 55,713 experiencing an addition. After adjusting for potential confounders, those with a medication change experienced an 10% increase in the odds of 30-day readmission (odds ratio, 1.10; SE, 0.019; p < 0.001). Comorbid drug use disorder was also associated with an increased odds of readmission after controlling for other covariates. These findings suggest important factors that clinicians should be aware of when discharging patients with SMI.