Depressive breakthrough

Exercise training impacts skeletal muscle gene expression related to the kynurenine pathway

Exercise positively impacts mood and symptoms of depression; however, the mechanisms underlying these effects are not fully understood. Recent evidence highlights a potential role for skeletal muscle-derived transcription factors to influence tryptophan metabolism, along the kynurenine pathway, which has important implications in depression. This has important consequences for older adults, whose age-related muscle deterioration may influence this pathway and may increase their risk for depression. Although exercise training has been shown to improve skeletal muscle mass in older adults, whether this also translates into improvements in transcription factors and metabolites related to the kynurenine pathway has yet to be examined. The aim of the present study was to examine the influence of a 12-wk exercise program on skeletal muscle gene expression of transcription factors, kynurenine aminotransferase (KAT) gene expression, and plasma concentrations of tryptophan metabolites (kynurenines) in healthy older men over 65 yr of age. Exercise training significantly increased skeletal muscle gene expression of transcription factors (peroxisome proliferator-activated receptor-γ coactivator 1α, peroxisome proliferator-activated receptor-α, and peroxisome proliferator-activated receptor-δ: 1.77, 1.99, 2.18-fold increases, respectively, P < 0.01] and KAT isoforms 1-4 (6.5, 2.1, 2.2, and 2.6-fold increases, respectively, P ≤ 0.01). Concentrations of plasma kynurenines were not altered. These results demonstrate that 12 wk of exercise training significantly altered skeletal muscle gene expression of transcription factors and gene expression related to the kynurenine pathway, but not circulating kynurenine metabolites in older men. These findings warrant future research to determine whether distinct exercise modalities or varying intensities could induce a shift in the kynurenine pathway in depressed older adults.

Targeting inflammation to influence mood following spinal cord injury: a randomized clinical trial

BACKGROUND

The purpose of the present study was to examine the efficacy of targeting inflammation as a means of improving mood following spinal cord injury (SCI) and explore the potential mechanisms of action.

METHODS

The study was a randomized, parallel-group, controlled, clinical trial (NCT02099890) whereby 20 participants with varying levels and severities of SCI were randomized (3:2) to either the treatment group, consisting of a 12-week anti-inflammatory diet, or control group. Outcome measures were assessed at baseline, 1 and 3 months, and consisted of CES-D scores of depression, markers of inflammation as assessed by various pro- and anti-inflammatory cytokines and several amino acids related to depression.

RESULTS

A significant group × time interaction was found for CES-D (Center for Epidemiologic studies Depression Scale) score (p = 0.01), the TRP/LNAA (tryptophan/large neutral amino acid) ratio (p = 0.04), the composite score of pro-inflammatory cytokines (p = 0.04), IL-1β (interleukin-1 beta) (p = 0.04), and IFN-γ (interferon gamma) (p = 0.03). Pearson's r correlation showed significance between the ∆IL-1β and both the ∆CES-D score (r = 0.740, p < 0.01) and the ∆KYN/TRP (kynurenine/tryptophan) ratio (r = 0.536, p = 0.02). The ∆KYN/TRP ratio was also significantly correlated with the ∆CES-D score (r = 0.586, p = 0.01). Mediation analysis showed that the relationship between the ∆KYN/TRP ratio and the ∆CES-D score was mediated by the ∆IL-1β. Subgroup analysis showed that participants with high CES-D scores had significantly higher concentrations of IL-1β, and all correlations were maintained or strengthened within this subgroup.

CONCLUSIONS

Overall, the results demonstrated the effectiveness of targeting inflammation as a means of improving mood in SCI, with potential mechanisms relating to the reduction in IL-1β and improvements in levels of neuroactive compounds related to the kynurenine pathway. Due to the limited sample size, results should be interpreted with caution; however, they are worthy of further examination due to the potential impact of inflammation on depression.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT02099890 .

The common inflammatory etiology of depression and cognitive impairment: a therapeutic target

Chronic inflammation has been shown to contribute to the development of a wide variety of disorders by means of a number of proposed mechanisms. Depression and cognitive impairment are two such disorders which may share a closely linked inflammatory etiology. The ability of inflammatory mediators to alter the activity of enzymes, from key metabolic pathways, may help explain the connection between these disorders. The chronic up-regulation of the kynurenine pathway results in an imbalance in critical neuroactive compounds involving the reduction of tryptophan and elevation of tryptophan metabolites. Such imbalances have established implications in both depression and cognitive impairment. This may implicate the immune system as a potential therapeutic target in the treatment of these disorders. The most common treatment modalities currently utilized, involve drug interventions which act on downstream targets. Such treatments help to reestablish protein balances, but fail to treat the inflammatory basis of the disorder. The use of anti-inflammatory interventions, such as regular exercise, may therefore, contribute to the effectiveness of current drug interventions in the treatment of both depression and cognitive impairment.

Tardive dysphoria: antidepressant-induced chronic depression

Objectives: A significant number of depressed individuals experience inadequate benefit from long-term antidepressant use. This paper investigates the hypothesis that in some individuals persistent use of antidepressants may be prodepressant.

Methods: Literature regarding the effect of long-term use of antidepressants was reviewed by searching PubMed and Ovid data bases with terms: antidepressant tachyphylaxis, treatment-resistant depression, chronic depression and antidepressant tolerance.

Results: Antidepressant treatment-resistant patients frequently had a positive initial response to antidepressants. When resistance appeared, initial increases in dose or medication changes usually resulted in transient improvement. Eventually, the episodic course of the original depressive illness was replaced with a continuous, unresponsive depressive syndrome. We propose the term tardive dysphoria to describe this phenomenon.

Conclusions: The phenomenon of antidepressantinduced depression, or tardive dysphoria, needs to be experimentally examined in blinded, randomised antidepressant discontinuation studies.

Glia atrophy in the hippocampus of chronic unpredictable stress-induced depression model rats is reversed by electroacupuncture treatment

BACKGROUND

Growing evidence indicates that glia atrophy contributes to the pathophysiology and possibly the pathogenesis of major depressive disorder. Electroacupuncture (EA), one of Chinese traditional therapy, has potent antidepressant-like effect in many clinical studies. The mechanism by which EA improves behavioral deficits is still unclear.

METHOD

Chronic unpredictable stress (CUS)-induced depression model rats were used to study the effect of EA treatment. EA was performed on acupoints 'Bai-Hui' (Du 20) and unilateral 'An-Mian' (EX 17) once daily for three consecutive weeks, two weeks post CUS procedure. The antidepressant-like effect of EA treatment was analyzed by physical state (PS) and open field test (OFT). Astrocytic marker glial fibrillary acidic protein (GFAP) level in the hippocampus was detected by immunohistochemistry, Western blot analysis and reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Exposure to CUS resulted in a decrease of behavioral activity, whereas a daily session of EA treatment significantly reversed the behavioral deficit of these depression model rats. Moreover, the levels of GFAP mRNA and protein were decreased in the hippocampus of depression model rats. Intriguingly, EA treatment blocked effectively the decreased GFAP level.

LIMITATION

The relative small number of the depression model rats may cause some bias of behavioral tests.

CONCLUSION

EA has potential antidepressant-like effect on CUS-induced depression model rats, which might be mediated by affecting the glial atrophy in the hippocampus.

Autonomy, stress, and treatment of depression

Psychotherapy canhelp patients understand the triggers for depression and how to deal with them. Paul Biegler argues that these effects should be given moral weight when deciding on treatment

Use of bupropion in combination with serotonin reuptake inhibitors

Incomplete symptom remission and sexual side effects are common problems for which bupropion often is added to treatment with selective serotonin and serotonin-norepinephrine reuptake inhibitors (SSRIs and SNRIs) for patients with major depressive disorder (MDD). This article reviews the literature on combining bupropion with SSRIs or SNRIs. We used MEDLINE to select studies that included patients diagnosed with MDD treated with any combination of bupropion and an SSRI or SNRI, either to enhance antidepressant response or to ameliorate antidepressant-associated sexual dysfunction. Bibliographies of located articles were searched for additional studies. Controlled and open-label studies support the effectiveness of bupropion in reversing antidepressant-associated sexual dysfunction, whereas open trials suggest that combination treatment with bupropion and an SSRI or SNRI is effective for the treatment of MDD in patients refractory to the SSRI, SNRI, or bupropion alone. The available data suggest that, although not an approved indication, the combination of bupropion and either an SSRI or an SNRI is generally well tolerated, can boost antidepressant response, and can reduce SSRI or SNRI-associated sexual side effects. Additional randomized controlled studies are needed to answer important questions, such as those regarding optimal dose and duration of treatment.

Placebo-controlled continuation treatment with mirtazapine: acute pattern of response predicts relapse

Pattern of response to antidepressants has been proposed as a method to identify patients whose improvement is more likely due to drug vs those whose improvement on drug is more likely to be a placebo effect. It is hypothesized that those with 'true-drug initial response pattern' are most likely to benefit from continuation treatment. The relationship between acute patterns of response and subsequent placebo-controlled continuation treatment with the antidepressant mirtazapine is examined. A total of 410 outpatients were treated openly with mirtazapine for 8-12 weeks. Patients who remitted in the acute phase were randomized to continue the same dose of mirtazapine or switched to placebo. Acute phase responders were classified as 'placebo initial response pattern' (early responders and nonpersistent responders) and 'true-drug initial response pattern' (delayed and persistent responders). Of those with a 'true-drug initial response pattern,' 10/40 (25.0%) relapsed with continuation mirtazapine, and 23/41 (56.1%) relapsed when switched to placebo. The difference (31.1%) is significant. Of those with a 'placebo initial response pattern,' 5/36 (13.9%) relapsed with continuation mirtazapine, and 12/39 (30.8%) relapsed with placebo substitution. This difference (16.9%) is not statistically significant. Moreover, the relapse rate for 'true-drug initial response pattern' patients switched to placebo (56.1%) was also significantly greater than for 'placebo initial response pattern' patients switched to placebo (30.8%). It has been suggested that patients with late onset and persistence are more likely to have improved because of drug. This hypothesis gains support from this study because of the different relapse rates of 'true-drug' responders on drug and placebo. The low relapse rate for patients with an acute placebo pattern switched to placebo suggests specific drug effect played a smaller role in their initial improvement.

Recurrence of low back pain: definition-sensitivity analysis using administrative data

STUDY DESIGN

Retrospective analysis of administrative claims data in a single workers' compensation jurisdiction.

OBJECTIVES

To evaluate the effects of alternative definitions and follow-up parameters on rates of low back pain recurrence based on detailed administrative data.

SUMMARY OF BACKGROUND DATA

Previous studies reported low back pain recurrence rates ranging from 14% to 45%, without consistency in definitions of recurrence or specifications of follow-up.

METHODS

Patients with new claims for low back pain reported in New Hampshire to a large workers' compensation provider in 1996 and 1997 were selected (N = 2944). Definitions of recurrence included: new workers' compensation claim, new episode of care, and new episode of lost work time (work disability). For the latter two definitions, various minimum between-episode gaps were applied and related to recurrence rates. Two follow-up structures (constant length of follow-up post end of the first episode and fixed-period length of follow-up since the onset of low back pain) were examined for sensitivity of recognizing low back pain recurrence, with a maximum of 3-year follow-up.

RESULTS

Recurrence rate using a claims-based definition was 7.9% and 7.1% for the entire cohort and the subset with work disability days, respectively, for the 3 years of follow-up. Care-based recurrence rates ranged between 12% and 49%, whereas disability-based recurrence rates ranged between 6% and 17% over the 3 years, inversely related to the length of the minimum between-episode gap (R = -0.86 for disability and care, P < 0.001). Two-year follow-up was sufficient to identify 85% to 100% of recurrences regardless of the follow-up structure.

CONCLUSIONS

Recurrence rates are highly sensitive to variations in definitions. Consistency of definitions and application across studies is required to enable valid comparisons.

A pilot, open study of sertraline in outpatients with treatment-resistant depression (TRD) or with a history of TRD who responded but later relapsed

While most depressed patients are prescribed a selective serotonin reuptake inhibitor (SSRI) as an initial treatment, the use of SSRIs as a second or third-line treatment for depression is not as prevalent. This trial assessed the efficacy of sertraline for patients with treatment-resistant depression (TRD) or patients with a history of TRD who responded but later relapsed. Twelve patients with TRD who had not responded to a number of antidepressant trials (n=7), or had responded but subsequently suffered a relapse (n=5), were enrolled in an 8-week, open trial of sertraline. Both a completer analysis (n=6) and an intent-to-treat (ITT) analysis (n=12) were performed to evaluate sertraline response rates. Using a completer analysis, four patients (66.6%) were classified as responders; one (16.7%) as a partial responder and one (16.7%) as a non-responder. An ITT analysis resulted in five (41.7%) patients being classified as responders; one (8.3%) as a partial responder and six (50%) as non-responders. Of the four responders in the completer analysis, three (50%) achieved remission. Of the five responders in the ITT analysis, four (33.3%) achieved remission. Overall, two of seven (28.6%) non-responders and three of five (60.0%) relapsers responded to sertraline. The present results suggest the potential utility of sertraline for patients with TRD, or those with a history of TRD who responded but later relapsed, and warrant larger, placebo-controlled studies to further explore the potential role of sertraline for such patients.

Predictors of response in depression

Conflicting or sparse data on predictors of treatment response in depression have resulted in lack of clear guidelines in choosing antidepressant treatment. Critical to treatment outcome are accurate diagnosis and adequate treatment. Other data easy to obtain, such as age, gender, and marital status, have failed to be consistent predictors; more elaborate studies, such as receptor analysis or neuroimaging, are not yet accessible to most clinicians or economically feasible; however, they offer hope for the future, when more biologically based diagnostic distinctions may come to guide treatment choices.

Diagnosis and definition of treatment-resistant depression

Treatment-resistant depression (TRD) typically refers to inadequate response to at least one antidepressant trial of adequate doses and duration. TRD is a relatively common occurrence in clinical practice, with up to 50% to 60% of the patients not achieving adequate response following antidepressant treatment. A diagnostic re-evaluation is essential to the proper management of these patients. In particular, the potential role of several contributing factors, such as medical and psychiatric comorbidity, needs to be taken into account. An accurate and systematic assessment of TRD is a challenge to both clinicians and researchers, with the use of clinician-rated or self-rated instruments being perhaps quite helpful. It is apparent that there may be varying degrees of treatment resistance. Some staging methods to assess levels of treatment resistance in depression are being developed, but need to be tested empirically.