Neuroimmune modulation by tryptophan derivatives in neurological and inflammatory disorders

The nervous and immune systems are highly developed, and each performs specialized physiological functions. However, they work together, and their dysfunction is associated with various diseases. Specialized molecules, such as neurotransmitters, cytokines, and more general metabolites, are essential for the appropriate regulation of both systems. Tryptophan, an essential amino acid, is converted into functional molecules such as serotonin and kynurenine, both of which play important roles in the nervous and immune systems. The role of kynurenine metabolites in neurodegenerative and psychiatric diseases has recently received particular attention. Recently, we found that hyperactivity of the kynurenine pathway is a critical risk factor for septic shock. In this review, we first outline neuroimmune interactions and tryptophan derivatives and then summarized the changes in tryptophan metabolism in neurological disorders. Finally, we discuss the potential of tryptophan derivatives as therapeutic targets for neuroimmune disorders.

Major depressive disorder: hypothesis, mechanism, prevention and treatment

Worldwide, the incidence of major depressive disorder (MDD) is increasing annually, resulting in greater economic and social burdens. Moreover, the pathological mechanisms of MDD and the mechanisms underlying the effects of pharmacological treatments for MDD are complex and unclear, and additional diagnostic and therapeutic strategies for MDD still are needed. The currently widely accepted theories of MDD pathogenesis include the neurotransmitter and receptor hypothesis, hypothalamic-pituitary-adrenal (HPA) axis hypothesis, cytokine hypothesis, neuroplasticity hypothesis and systemic influence hypothesis, but these hypothesis cannot completely explain the pathological mechanism of MDD. Even it is still hard to adopt only one hypothesis to completely reveal the pathogenesis of MDD, thus in recent years, great progress has been made in elucidating the roles of multiple organ interactions in the pathogenesis MDD and identifying novel therapeutic approaches and multitarget modulatory strategies, further revealing the disease features of MDD. Furthermore, some newly discovered potential pharmacological targets and newly studied antidepressants have attracted widespread attention, some reagents have even been approved for clinical treatment and some novel therapeutic methods such as phototherapy and acupuncture have been discovered to have effective improvement for the depressive symptoms. In this work, we comprehensively summarize the latest research on the pathogenesis and diagnosis of MDD, preventive approaches and therapeutic medicines, as well as the related clinical trials.

Chronic pain predicts a worse response to depression treatment, regardless of thyroid function or psychotropics prescribed

BACKGROUND

Chronic pain (CP) and thyroid hormones' (TH) abnormalities are associated with depression, but the impact of pain and TH fluctuation on the response to depression treatment is uncertain.

METHODS

Eighty-eight patients with major depression were evaluated before and after 6 months of specific treatment, through scales of symptoms' severity (HAM-D-17), psychomotor disturbance (CORE), and quality of life (WHOQOL-Bref). We reviewed psychiatric medications and measured TSH, T3 and T4. We used Generalized Estimating Equations to assess the interaction effect between CP and treatment time on depression severity and TH levels, and Bonferroni to compare means.

RESULTS

47.7 % of the patients had CP. Patients with and without CP did not differ at baseline. At follow-up, those with CP experienced a more modest decrease in symptoms' severity and no improvement in any domain of psychomotor disturbance, contrasting with a decrease of over 40 % from the baseline values of CORE in patients without CP (non-CP). Initial and final scores were respectively: HAM-D CP 24.06 and 19.3, Δ = -4.75; HAM-D non-CP 22.92 and 14.7, Δ = -8.21; CORE CP 5.36 and 5.24, Δ = -0.12; CORE non-CP 5.8 and 3.22, Δ = -2.57. There was no interaction with TH or life quality. Model adjustments for psychotropic drugs received and sensitivity analysis excluding somatic symptoms from severity scales did not impact the results.

LIMITATIONS

Findings may not replicate in mildly depressed patients from primary care. Pain scales were not applied.

CONCLUSIONS

Individuals with chronic pain showed a suboptimal response to depression treatment, regardless of the medications used or TH levels.

Blocking the major inflammatory pathways by newly synthesized thiadiazine derivatives via in-vivo, in-vitro and in-silico mechanism

A series of new thiadiazine derivatives including 2-(5-alkyl/aryl-6-thioxo-1,3,5-thiadiazinan-3-yl) propanoic acids (a) and 4-methyl-2-(5-alkyl/aryl-6-thioxo-1,3,5-thiadiazinan-3-yl) pentanoic acids (b) were synthesized by reacting primary alkyl/aryl amines with CS2, followed by reaction with formaldehyde and amino acids. The chemical structures of synthesized compounds were confirmed by 13C- NMR and 1H- NMR techniques. The inhibitory potential of major inflammatory enzymes, COX-2 and 5-LOX was examined. Moreover, anti-nociceptive and anti-inflammatory activities were evaluated in the in vivo thermally induced nociceptive, and carrageenan induced paw edema models in mice. The in-vitro results reflect that these compounds exhibited concentration dependent inhibition of COX-2 and 5-LOX. The tested compounds at 50 mg/kg showed significant effect on thermally induced pain, and reduced latency time (seconds) as compared to the vehicle treated animals. Moreover, tested compounds exhibited percent inhibition of paw edema in the carrageenan induced paw edema model in mice. Furthermore, the binding modes of the most active COX-2 and 5-LOX inhibitors were determined through computational methods. The computational study reflects that the docked compounds have high binding affinities for COX-2 and 5-LOX enzymes, which leads to inhibition of these enzymes.

Self-Reported Chronic Back Pain and Current Depression in Brazil: A National Level Study

There is limited literature investigating the association between chronic back pain (CBP) and depression in Brazil. This study evaluates the association between CBP, CBP-related physical limitations (CBP-RPL), and self-reported current depression (SRCD), in a nationally representative sample of Brazilian adults. The data for this cross-sectional study came from the 2019 Brazilian National Health Survey (n = 71,535). The Personal Health Questionnaire depression scale (PHQ-8) was used to measure the SRCD outcome. The exposures of interest were self-reported CBP and CBP-RPL (none, slight, moderate, and high limitation). Multivariable weighted and adjusted logistic regression models were used to investigate these associations. The weighted prevalence of SRCD among CBP was 39.5%. There was a significant weighted and adjusted association between CBP and SRCD (weighted and adjusted odds ratio (WAOR) 2.69 (95% CI: 2.45-2.94). The WAOR of SRCD among individuals with high, moderate, and slight levels of physical limitation was significantly greater than for those without physical limitation due to CBP. Among Brazilian adults with high levels of CBP-RPL, there was over a five-fold increased risk of SRCD compared to those without CBP-RPL. These results are important for increasing awareness of the link between CBP and SRCD and for informing health services policies.

Depression Treatment Initiation Among Patients With Versus Without Chronic Pain

OBJECTIVE

The purpose of this study was to examine the extent to which the presence of chronic noncancer pain (CNCP) impacts the likelihood that patients with diagnoses of depression will initiate depression treatment compared with those without CNCP.

METHODS

We performed a retrospective cohort study of Kaiser Permanente of Georgia members older than 18 years who received a diagnosis of depression. Demographics and medical history were extracted from the electronic health record database. Members were further classified by the presence or absence of a CNCP diagnosis. Outcomes of interest were treated as time dependent and included ( 1 ) time to fulfillment of a new antidepressant medication and ( 2 ) time to a follow-up mental health encounter. Outcomes were compared between members with and without a CNCP diagnosis using Kaplan-Meier survival curves and Cox proportional hazard regression models.

RESULTS

During the study period, 22,996 members met the inclusion criteria and 27.4% had a diagnosis of CNCP. In the matched sample, there was no difference in the time to a new antidepressant fill among members with and without CNCP (hazard ratio = 0.96; 95% confidence interval = 0.90-1.02; p = .18). In contrast, members with CNCP were significantly less likely to have a new mental health encounter after diagnosis (hazard ratio = 0.87; 95% confidence interval = 0.81-0.94; p < .001).

CONCLUSIONS

Patients with CNCP were significantly less likely to have a new mental health encounter after a depression diagnosis compared with patients without CNCP. Additional outreach and consideration may be needed to improve initiation of depression treatment for newly diagnosed patients with comorbid depression and CNCP.

Multiple modulatory roles of serotonin in chronic pain and injury-related anxiety

Chronic pain is long-lasting pain that often persists during chronic diseases or after recovery from disease or injury. It often causes serious side effects, such as insomnia, anxiety, or depression which negatively impacts the patient's overall quality of life. Serotonin (5-HT) in the central nervous system (CNS) has been recognized as an important neurotransmitter and neuromodulator which regulates various physiological functions, such as pain sensation, cognition, and emotions-especially anxiety and depression. Its widespread and diverse receptors underlie the functional complexity of 5-HT in the CNS. Recent studies found that both chronic pain and anxiety are associated with synaptic plasticity in the anterior cingulate cortex (ACC), the insular cortex (IC), and the spinal cord. 5-HT exerts multiple modulations of synaptic transmission and plasticity in the ACC and the spinal cord, including activation, inhibition, and biphasic actions. In this review, we will discuss the multiple actions of the 5-HT system in both chronic pain and injury-related anxiety, and the synaptic mechanisms behind them. It is likely that the specific 5-HT receptors would be new promising therapeutic targets for the effective treatment of chronic pain and injury-related anxiety in the future.

Pain severity and pain interference during major depressive episodes treated with escitalopram and aripiprazole adjunctive therapy: a CAN-BIND-1 report

Escitalopram may have pain-alleviating effects for patients with comorbid pain and depression. This study aimed to quantify improvements in pain for patients on escitalopram and adjunctive aripiprazole. A secondary analysis of the CAN-BIND-1 trial was conducted which only included participants with a current depressive episode and pain. Participants received escitalopram (10-20mg) for eight weeks and treatment response was defined as a reduction in Montgomery-Åsberg Depression Rating Scale (MADRS) of at least 50% from baseline. Non-responders at week 8 received adjunctive aripiprazole (2-10mg) for another eight weeks. The Brief Pain Inventory's pain severity (PSC) and pain interference (PIC) composite scores were measured at baseline, week 8, and week 16. Linear regression was used to determine how PSC and PIC differed between treatment responders and non-responders. Eighty-two participants with pain and depression received escitalopram. PSC and PIC decreased significantly regardless of treatment response at week 8, although responders had significantly lower PSC and PIC than non-responders. For the group receiving aripiprazole after week 8, neither PSC nor PIC improved further. Further research is needed to identify interventions that might treat both pain and depression symptoms.

A single oral dose of citalopram increases interoceptive insight in healthy volunteers

RATIONALE

Interoception is the signalling, perception, and interpretation of internal physiological states. Many mental disorders associated with changes of interoception, including depressive and anxiety disorders, are treated with selective serotonin reuptake inhibitors (SSRIs). However, the causative link between SSRIs and interoception is not yet clear.

OBJECTIVES

To ascertain the causal effect of acute changes of serotonin levels on cardiac interoception.

METHODS

Using a within-participant placebo-controlled design, forty-seven healthy human volunteers (31 female, 16 male) were tested on and off a 20 mg oral dose of the commonly prescribed SSRI, citalopram. Participants made judgements on the synchrony between their heartbeat and auditory tones and then expressed confidence in each judgement. We measured three types of interoceptive cognition.

RESULTS

Citalopram increased cardiac interoceptive insight, measured as correspondence of self-reported confidence to the likelihood that interoceptive judgements were actually correct. This effect was driven by enhanced confidence for correct interoceptive judgements and was independent of measured cardiac and reported subjective effects of the drug.

CONCLUSIONS

An acute change of serotonin levels can increase insight into the reliability of inferences made from cardiac interoceptive sensations.

Beating Pain with Psychedelics: Matter over Mind?

Basic pain research has shed light on key cellular and molecular mechanisms underlying nociceptive and phenomenological aspects of pain. Despite these advances, [[we still yearn for] the discovery of novel therapeutic strategies to address the unmet needs of about 70% of chronic neuropathic pain patients whose pain fails to respond to opioids as well as to other conventional analgesic agents. Importantly, a substantial body of clinical observations over the past decade cumulatively suggests that the psychedelic class of drugs may possess heuristic value for understanding and treating chronic pain conditions. The present review presents a theoretical framework for hitherto insufficiently understood neuroscience-based mechanisms of psychedelics' potential analgesic effects. To that end, searches of PubMed-indexed journals were performed using the following Medical Subject Headings' terms: pain, analgesia, inflammatory, brain connectivity, ketamine, psilocybin, functional imaging, and dendrites. Recursive sets of scientific and clinical evidence extracted from this literature review were summarized within the following key areas: (1) studies employing psychedelics for alleviation of physical and emotional pain; (2) potential neuro-restorative effects of psychedelics to remediate the impaired connectivity underlying the dissociation between pain-related conscious states/cognitions and the subcortical activity/function leading to the eventual chronicity through immediate and long-term effects on dentritic plasticity; (3) anti-neuroinflammatory and pro-immunomodulatory actions of psychedelics as the may pertain to the role of these factors in the pathogenesis of neuropathic pain; (4) safety, legal, and ethical consideration inherent in psychedelics' pharmacotherapy. In addition to direct beneficial effects in terms of reduction of pain and suffering, psychedelics' inclusion in the analgesic armamentarium will contribute to deeper and more sophisticated insights not only into pain syndromes but also into frequently comorbid psychiatric condition associated with emotional pain, e.g., depressive and anxiety disorders. Further inquiry is clearly warranted into the above areas that have potential to evolve into further elucidate the mechanisms of chronic pain and affective disorders, and lead to the development of innovative, safe, and more efficacious neurobiologically-based therapeutic approaches.

Antidepressant and Anxiolytic Effects of Medicinal Cannabis Use in an Observational Trial

Background: Anxiety and depressive disorders are highly prevalent. Patients are increasingly using medicinal cannabis products to treat these disorders, but little is known about the effects of medicinal cannabis use on symptoms of anxiety and depression. The aim of the present observational study was to assess general health in medicinal cannabis users and non-using controls with anxiety and/or depression. Methods: Participants (368 Cannabis Users; 170 Controls) completed an online survey assessing anxiety and depressive symptoms, cannabis product use, sleep, quality of life, and comorbid chronic pain. Participants that completed this baseline survey were then invited to complete additional follow-up surveys at 3-month intervals. Baseline differences between Cannabis Users and Controls were assessed using independent-samples t-tests and generalized linear mixed effects models were used to assess the impact of initiating cannabis product use, sustained use, or discontinuation of use on anxiety and depressive symptoms at follow-up. Results: Medicinal cannabis use was associated with lower self-reported depression, but not anxiety, at baseline. Medicinal cannabis users also reported superior sleep, quality of life, and less pain on average. Initiation of medicinal cannabis during the follow-up period was associated with significantly decreased anxiety and depressive symptoms, an effect that was not observed in Controls that never initiated cannabis use. Conclusions: Medicinal cannabis use may reduce anxiety and depressive symptoms in clinically anxious and depressed populations. Future placebo-controlled studies are necessary to replicate these findings and to determine the route of administration, dose, and product formulation characteristics to optimize clinical outcomes.

Identifying c-fos Expression as a Strategy to Investigate the Actions of General Anesthetics on the Central Nervous System

Although general anesthetics have been used in the clinic for more than 170 years, the ways in which they induce amnesia, unconsciousness, analgesia, and immobility remain elusive. Modulations of various neural nuclei and circuits are involved in the actions of general anesthetics. The expression of the immediate-early gene c-fos and its nuclear product, c-fos protein, can be induced by neuronal depolarization; therefore, c-fos staining is commonly used to identify the activated neurons during sleep and/or wakefulness, as well as in various physiological conditions in the central nervous system. Identifying c-fos expression is also a direct and convenient method to explore the effects of general anesthetics on the activity of neural nuclei and circuits. Using c-fos staining, general anesthetics have been found to interact with sleep- and wakefulness-promoting systems throughout the brain, which may explain their ability to induce unconsciousness and emergence from general anesthesia. This review summarizes the actions of general anesthetics on neural nuclei and circuits based on a c-fos expression.

Depression and Pain: use of antidepressant

Background:

Emotional disorders are common comorbid affectations that exacerbate the severity and persistence of chronic pain. Specifically, depressive symptoms can lead to an excessive duration and intensity of pain. Clinical and preclinical studies have been focused on the underlying mechanisms of chronic pain and depression comorbidity and the use of antidepressants to reduce pain.

Aim:

This review provides an overview of the comorbid relationship of chronic pain and depression, the clinical and pre-clinical studies performed on the neurobiological aspects of pain and depression, and the use of antidepressants as analgesics.

Methods:

A systematic search of literature databases was conducted according to pre-defined criteria. The authors independently conducted a focused analysis of the full-text articles.

Results:

Studies suggest that pain and depression are highly intertwined and may co-exacerbate physical and psychological symptoms. One important biochemical basis for pain and depression focuses on the serotonergic and norepinephrine system, which have been shown to play an important role in this comorbidity. Brain structures that codify pain are also involved in mood. It is evident that using serotonergic and norepinephrine antidepressants are strategies commonly employed to mitigate pain

Conclusion:

Literature indicates that pain and depression impact each other and play a prominent role in the development and maintenance of other chronic symptoms. Antidepressants continue to be a major therapeutic tool for managing chronic pain. Tricyclic antidepressants (TCAs) are more effective in reducing pain than Selective Serotonin Reuptake Inhibitors (SSRIs) and Serotonin-Noradrenaline Reuptake Inhibitors (SNRIs).

The Influence of Cross-Fostering on Alcohol Consumption and Depressive-Like Behaviors in HA and LA Mice: The Role of the Endogenous Opioid System

The development of alcohol dependence and depression is determined by various genetic and environmental factors. In the presented study, we used high analgesia (HA) and low analgesia (LA) mouse lines, characterized by different endogenous opioid system activity and divergent blood–brain barrier permeability, to determine the influence of cross-fostering of these lines raised by surrogate mothers on ethanol consumption and development of depressive-like behaviors. We also investigated ethanol drinking by biological parents or surrogate mothers. Furthermore, we investigated whether these parental changes would alter the effect of naloxone on ethanol intake and depressive-like behaviors in offspring. Our results reveal that cross-fostering of HA and LA raised by surrogate mothers has a greater impact on depressive-like behaviors than ethanol consumption. Ethanol intake by biological parents substantially affected depressive-like behaviors and ethanol consumption in offspring. Moreover, ethanol intake by biological parents or an adoptive mother modified the effect of naloxone on ethanol consumption and preference and depressive-like behaviors in the HA offspring only. Together, these results indicate that cross-fostering differentially affects the effect of naloxone on alcohol consumption and the development of depression.

Serotonin-Its Synthesis and Roles in the Healthy and the Critically Ill

Serotonin (5-hydroxytryptamine, 5-HT) plays two important roles in humans-one central and the other peripheral-depending on the location of the 5-HT pools of on either side of the blood-brain barrier. In the central nervous system it acts as a neurotransmitter, controlling such brain functions as autonomic neural activity, stress response, body temperature, sleep, mood and appetite. This role is very important in intensive care, as in critically ill patients multiple serotoninergic agents like opioids, antiemetics and antidepressants are frequently used. High serotonin levels lead to altered mental status, deliria, rigidity and myoclonus, together recognized as serotonin syndrome. In its role as a peripheral hormone, serotonin is unique in controlling the functions of several organs. In the gastrointestinal tract it is important for regulating motor and secretory functions. Apart from intestinal motility, energy metabolism is regulated by both central and peripheral serotonin signaling. It also has fundamental effects on hemostasis, vascular tone, heart rate, respiratory drive, cell growth and immunity. Serotonin regulates almost all immune cells in response to inflammation, following the activation of platelets.

Therapeutic effects of Silexan on somatic symptoms and physical health in patients with anxiety disorders: A meta-analysis

A meta-analysis was performed to examine therapeutic effects of Silexan on somatic symptoms, including insomnia/fatigue, and physical health in patients with anxiety disorders. Five randomized, placebo-controlled trials were included in this analysis: The efficacy of Silexan (80 mg/day) was investigated in patients with subthreshold anxiety disorders (three trials) and in patients with generalized anxiety disorder (two trials). Silexan was superior to placebo in terms of the mean change from baseline in the Hamilton Anxiety Rating Scale (HAMA) subscore somatic anxiety at week 10 with a standardized mean difference of -0.31 [95% Cl: -0.52 to -0.10, p = .004]. Treatment effects of silexan on somatic anxiety were independent of gender and age. Statistically significant differences were also shown for single HAMA items somatic muscular, cardiovascular, respiratory, and genitourinary symptoms, indicating clinical relevance with small to medium effects of Silexan. Similar clinically meaningful effects of Silexan on SF-36 physical health, including reduced bodily pain and improved general health, and on insomnia complaints and fatigue, were demonstrated. In this meta-analysis including all placebo-controlled clinical trials in patients with anxiety disorders to date, statistically significant and clinically meaningful advantages of Silexan over placebo treatment were found in improving somatic symptoms and physical health.

Maternal separation increases pain sensitivity by reducing the activity of serotonergic neurons in the dorsal raphe nucleus and noradrenergic neurons in locus coeruleus

Animals subjected to early life maternal separation exhibit increased sensitivity to chemical, thermal, and mechanical stimuli during adulthood. However, the mechanism by which maternal separation can alter pain sensitivity in adulthood has not yet been investigated. Thus, we aimed to evaluate the activity of serotonergic and noradrenergic neurons and the effect of serotonin (5-HT) and noradrenaline (NA) reuptake inhibitors in male and female Wistar rats subjected to maternal separation. This study consisted of two experiments: 1) to confirm whether maternal separation increased pain sensitivity (n = 8 per group) and to evaluate the activity of serotonergic neurons in the dorsal raphe nucleus and noradrenergic neurons in locus coeruleus in animals subjected to maternal separation in comparison to controls (n = 6 per group); and 2) to evaluate the effect of fluoxetine (a selective 5-HT reuptake inhibitor) and desipramine (a NA reuptake inhibitor) on sensitivity to chemical stimulation using formalin in animals subjected to maternal separation (n = 8 per group). Our findings indicated that maternal separation increases an animal's sensitivity to painful chemical stimulation and reduces the activity of 5-HT and NA neurons. In addition, acute pretreatment with a 5-HT or NA reuptake inhibitor prevented the increased response to painful stimulation induced by maternal separation. In conclusion, maternal separation increases pain sensitivity by reducing the activity of serotonergic neurons in the dorsal raphe nucleus and noradrenergic neurons in locus coeruleus. This study contributes to possible treatments for pain in individuals exposed to early life stress.

dmPFC-vlPAG projection neurons contribute to pain threshold maintenance and antianxiety behaviors

The dorsal medial prefrontal cortex (dmPFC) has been recognized as a key cortical area for nociceptive modulation. However, the underlying neural pathway and the function of specific cell types remain largely unclear. Here, we show that lesions in the dmPFC induced an algesic and anxious state. Using multiple tracing methods including a rabies-based transsynaptic tracing method, we outlined an excitatory descending neural pathway from the dmPFC to the ventrolateral periaqueductal gray (vlPAG). Specific activation of the dmPFC/vlPAG neural pathway by optogenetic manipulation produced analgesic and antianxiety effects in a mouse model of chronic pain. Inhibitory neurons in the dmPFC were specifically activated using a chemogenetic approach, which logically produced an algesic and anxious state under both normal and chronic pain conditions. Antagonists of the GABAA receptor (GABAAR) or mGluR1 were applied to the dmPFC, which produced analgesic and antianxiety effects. In summary, the results of our study suggest that the dmPFC/vlPAG neural pathway might participate in the maintenance of pain thresholds and antianxiety behaviors under normal conditions, while silencing or suppressing the dmPFC/vlPAG pathway might be involved in the initial stages and maintenance of chronic pain and the emergence of anxiety-like behaviors.

Antidepressant-like activity of L-701324 in mice: A behavioral and neurobiological characterization

Antidepressants currently used in clinical practice have limitations such as low efficacy, slow onset and various adverse reactions. It has become necessary to develop novel antidepressants beyond monoaminergic drugs. L-701,324 is a potent NMDA receptor antagonist, and the purpose of this study was to investigate the possible antidepressant effects of L-701,324 in mice. Here, various methods including the forced swim test (FST), tail suspension test (TST), chronic unpredictable mild stress (CUMS) model of depression, western blotting and immunofluorescence, were used together. A single injection of L-701,324 exhibited antidepressant-like potential in the FST and TST without affecting the locomotor activity of mice. Repeated injection of L-701,324 not only prevented CUMS-induced depressive-like behaviors in mice, but also ameliorated the downregulating effects of CUMS on the hippocampal BDNF signaling cascade and neurogenesis. Furthermore, K252a, a potent inhibitor of the BDNF system, fully blocked the antidepressant-like activity of L-701,324 in mice. K252a administration also abolished the activating actions of L-701,324 on the hippocampal BDNF signaling cascade and neurogenesis in CUMS-treated mice. Collectively, these data indicated that L-701,324 possesses antidepressant-like activity in mice, which was mediated, at least in part, by promoting the hippocampal BDNF system.

Novel optimized biopolymer-based nanoparticles for nose-to-brain delivery in the treatment of depressive diseases

A valid option to bypass the obstacle represented by the blood–brain barrier (BBB) in brain delivery is the use of the unconventional intranasal route of administration. The treatment of depressive diseases, resulting from the depletion of a neurotransmitter in the inter-synaptic space, such as serotonin, is indirectly treated using molecules that can permeate the BBB unlike the latter. In the present article, a set of nanovectors were produced using a mucoadhesive biopolymer, i.e. alginate (Alg). Optimizing the reaction, polymeric nanoparticles having diameter of 30–70 nm were produced, and water stable multi-walled carbon nanotubes functionalized (MWCNT-COOH)/Alg complexes were obtained. These nanovectors were loaded with serotonin, evaluating drug loading/release. By means of Raman microscopy, the cellular internalization of the (MWCNT-COOH)/Alg complex was demonstrated. A complete biocompatibility on neuronal cells was proved for the whole set of nanovectors. Finally, a method of self-administration was tested, which involves the use of a household apparatus, such as an aerosol machine, observing a fine particulate, able to deliver the nanovectors through the nose.

A valid option to bypass the obstacle represented by the blood–brain barrier (BBB) in brain delivery is the use of the unconventional intranasal route of administration.

Neuropathic pain: mechanisms of development, principles of diagnostics and treatment

Neuropathic pain is a pain caused by a disease or focal damage to the somatosensory nervous system. The prevalence of chronic pain with neuropathic features in different countries is estimated at 7–10 %. Damages to the nervous system can occur at the level of peripheral nerves, plexus and dorsal roots (peripheral neuropathic pain) or spinal cord and brain (central neuropathic pain). Neuropathic pain is based on pathological activation of pain pathways. Neuropathic pain occurs with diabetic polyneuropathy more often than with all polyneuropathies of another etiology. Hyperglycemia is the major cause of chronic diabetes mellitus and its progression. Since the cause of pain can rarely be cured, treatment is usually symptomatic. Neuropathic pain is generally poorly controlled by analgesics. NB management is started with conservative pharmacotherapy before applying invasive analgesia. Although there are many drugs that can be used in patients with DPN, monotherapy can not always stop pain syndrome. In addition, the patient may not tolerate the full therapeutic dose of the drug. All this dictates the need for combination therapy.

Child Abuse and Neglect as Risk Factors for Comorbidity Between Depression and Chronic Pain in Adulthood

It is estimated that comorbidity between depression and chronic pain reaches more than half of the depressed adult patients around the world. Evidence indicates that some stressors, such as early-life stress (ELS), mediate the co-occurrence of depression and chronic pain. This study aimed to assess whether ELS or any of its subtypes could be considered as risk factors for comorbidity between depression and chronic pain. For this purpose, 44 patients in depressive episode were evaluated, in which 22 were diagnosed with depression and chronic pain, and the other 22 patients were diagnosed with depression but without chronic pain. Results had shown that ELS occurrence is more significant among depressive patients with chronic pain compared with those without pain. When subtypes of ELS were evaluated, the group of depressive patients with pain showed significantly higher prevalence of emotional neglect than those depressive participants without pain. Data analysis has shown that severity of the depressive symptoms has a significant impact on the total score of childhood trauma, emotional abuse, physical abuse, emotional neglect, and physical neglect, and that emotional abuse, sexual abuse, and physical neglect have significant impact on the severity of depression. In conclusion, our findings indicate that ELS can be considered as a risk factor for the comorbidity between depression and chronic pain.

Revisiting Tramadol: A Multi-Modal Agent for Pain Management

Tramadol-an atypical opioid analgesic-has a unique pharmacokinetic and pharmacodynamic profile, with opioidergic, noradrenergic, and serotonergic actions. Tramadol has long been used as a well-tolerated alternative to other drugs in moderate pain because of its opioidergic and monoaminergic activities. However, cumulative evidence has been gathered over the last few years that supports other likely mechanisms and uses of tramadol in pain management. Tramadol has modulatory effects on several mediators involved in pain signaling, such as voltage-gated sodium ion channels, transient receptor potential V1 channels, glutamate receptors, α₂-adrenoceptors, adenosine receptors, and mechanisms involving substance P, calcitonin gene-related peptide, prostaglandin E₂, and proinflammatory cytokines. Tramadol also modifies the crosstalk between neuronal and non-neuronal cells in peripheral and central sites. Through these molecular effects, tramadol could modulate peripheral and central neuronal hyperexcitability. Given the broad spectrum of molecular targets, tramadol as a unimodal analgesic relieves a broad range of pain types, such as postoperative, low back, and neuropathic pain and that associated with labor, osteoarthritis, fibromyalgia, and cancer. Moreover, tramadol has anxiolytic, antidepressant, and anti-shivering activities that could improve pain management outcomes. The aim of this review was to address these issues in the context of maladaptive physiological and psychological processes that are associated with different pain types.

Psychopharmacology of chronic pain

Chronic pain is a frequent condition that affects an estimated 20% of people worldwide, accounting for 15%-20% of doctors' appointments (Treede et al., 2015). It lacks the acute warning function of physiologic nociception, and instead involves the activation of multiple neurophysiologic mechanisms in the somatosensory system, a complex neuronal network under the control of powerful autoregulatory loops and able to undergo rapid neuroplastic alteration (Verdu et al., 2008). There is a growing body of research suggesting that some such pathways are shared by major psychologic disorders such as depression and anxiety, opening new avenues in co-treatment strategies. In particular, besides anticonvulsants, which are today used as analgesics, other psychopharmaceuticals, such as the tricyclic antidepressants, are displaying efficacy in the treatment of neuropathic and nociceptive chronic pain. The state of the art regarding the mechanisms of nociception and the pharmacology of both the neurotransmitters involved and the wide range of psychoactive compounds that may be useful in the treatment of chronic pain are discussed.

Comparative Effect of Collaborative Care, Pain Medication, and Duloxetine in the Treatment of Major Depressive Disorder and Comorbid (Sub)Chronic Pain: Results of an Exploratory Randomized, Placebo-Controlled, Multicenter Trial (CC:PAINDIP)

OBJECTIVE

Evidence exists for the efficacy of collaborative care (CC) for major depressive disorder (MDD), for the efficacy of the consequent use of pain medication against pain, and for the efficacy of duloxetine against both MDD and neuropathic pain. Their relative effectiveness in comorbid MDD and pain has never been established so far. This study explores the effectiveness of CC with pain medication and duloxetine, and CC with pain medication and placebo, compared with duloxetine alone, on depressive and pain symptoms. This study was prematurely terminated because of massive reorganizations and reimbursement changes in mental health care in the Netherlands during the study period and is therefore of exploratory nature.

METHODS

Three-armed, randomized, multicenter, placebo-controlled trial at three specialized mental health outpatient clinics with patients who screened positive for MDD. Interventions lasted 12 weeks. Pain medication was administered according to an algorithm that avoids opiate prescription as much as possible, where paracetamol, COX inhibitors, and pregabalin are offered as steps before opiates are considered. Patients who did not show up for three or more sessions were registered as non-compliant. Explorative, intention-to-treat and per protocol, multilevel regression analyses were performed. The trial is listed in the trial registration (http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1089; NTR number: NTR1089).

RESULTS

Sixty patients completed the study. Patients in all treatment groups reported significantly less depressive and pain symptoms after 12 weeks. CC with placebo condition showed the fastest decrease in depressive symptoms compared with the duloxetine alone group (b = -0.78; p = 0.01). Non-compliant patients (n = 31) did not improve over the 12-week period, in contrast to compliant patients (n = 29). Pain outcomes did not differ between the three groups.

CONCLUSION

In MDD and pain, patient's compliance and placebo effects are more important in attaining effect than choice of one of the treatments. Active pain management with COX inhibitors and pregabalin as alternatives to tramadol or other opiates might provide an attractive alternative to the current WHO pain ladder as it avoids opiate prescription as much as possible. The generalizability is limited due to the small sample size. Larger studies are needed.

Dental Management of Patients Who Have Undergone Oral Cancer Therapy

Oral cancer therapies are associated with orofacial complications that could result in dose-limiting cancer treatment and consequent suboptimal tumor control. Oral cancer treatment complications include oral mucositis, salivary gland hypofunction, odontogenic infections, pain, dermatitis, neurotoxicity, soft tissue fibrosis, trismus, osteoradionecrosis, and potential cancer recurrence. These complications significantly affect cancer survivorship, quality of life, and psychosocial status. Effective dental management of patients with oral cancer involves the coordination of care among several health care professionals before, during, and after cancer therapy. The goal is to minimize complications, and establish optimal quality of life for survivors.

Non-conventional features of peripheral serotonin signalling - the gut and beyond

Serotonin was first discovered in the gut, and its conventional actions as an intercellular signalling molecule in the intrinsic and extrinsic enteric reflexes are well recognized, as are a number of serotonin signalling pharmacotherapeutic targets for treatment of nausea, diarrhoea or constipation. The latest discoveries have greatly broadened our understanding of non-conventional actions of peripheral serotonin within the gastrointestinal tract and in a number of other tissues. For example, it is now clear that bacteria within the lumen of the bowel influence serotonin synthesis and release by enterochromaffin cells. Also, serotonin can act both as a pro-inflammatory and anti-inflammatory signalling molecule in the intestinal mucosa via activation of serotonin receptors (5-HT₇ or 5-HT₄ receptors, respectively). For decades, serotonin receptors have been known to exist in a variety of tissues other than the gut, but studies have now provided strong evidence for physiological roles of serotonin in several important processes, including haematopoiesis, metabolic homeostasis and bone metabolism. Furthermore, evidence for serotonin synthesis in peripheral tissues outside of the gut is emerging. In this Review, we expand the discussion beyond gastrointestinal functions to highlight the roles of peripheral serotonin in colitis, haematopoiesis, energy and bone metabolism, and how serotonin is influenced by the gut microbiota.

The association of psychedelic use and opioid use disorders among illicit users in the United States

BACKGROUND

Preliminary studies show psychedelic compounds administered with psychotherapy are potentially effective and durable substance misuse interventions. However, little is known about the association between psychedelic use and substance misuse in the general population. This study investigated the association between psychedelic use and past year opioid use disorders within illicit opioid users.

METHODS

While controlling for socio-demographic covariates and the use of other substances, the relationship between classic psychedelic use and past year opioid use disorders was analyzed within 44,000 illicit opioid users who completed the National Survey on Drug Use and Health from 2008 to 2013.

RESULTS

Among respondents with a history of illicit opioid use, psychedelic drug use is associated with 27% reduced risk of past year opioid dependence (weighted risk ratio = 0.73 (0.60-0.89) p = 0.002) and 40% reduced risk of past year opioid abuse (weighted risk ratio = 0.60 (0.41-0.86) p = 0.006). Other than marijuana use, which was associated with 55% reduced risk of past year opioid abuse (weighted risk ratio = 0.45 (0.30-0.66) p < 0.001), no other illicit drug was associated with reduced risk of past year opioid dependence or abuse.

CONCLUSION

Experience with psychedelic drugs is associated with decreased risk of opioid abuse and dependence. Conversely, other illicit drug use history is largely associated with increased risk of opioid abuse and dependence. These findings suggest that psychedelics are associated with positive psychological characteristics and are consistent with prior reports suggesting efficacy in treatment of substance use disorders.

5-HT modulation of pain perception in humans

INTRODUCTION

Although there is clear evidence for the serotonergic regulation of descending control of pain in animals, little direct evidence exists in humans. The majority of our knowledge comes from the use of serotonin (5-HT)-modulating antidepressants as analgesics in the clinical management of chronic pain.

OBJECTIVES

Here, we have used an acute tryptophan depletion (ATD) to manipulate 5-HT function and examine its effects of ATD on heat pain threshold and tolerance, attentional manipulation of nociceptive processing and mood in human volunteers.

METHODS

Fifteen healthy participants received both ATD and balanced amino acid (BAL) drinks on two separate sessions in a double-blind cross-over design. Pain threshold and tolerance were determined 4 h post-drink via a heat thermode. Additional attention, distraction and temperature discrimination paradigms were completed using a laser-induced heat pain stimulus. Mood was assessed prior and throughout each session.

RESULTS

Our investigation reported that the ATD lowered plasma TRP levels by 65.05 ± 7.29% and significantly reduced pain threshold and tolerance in response to the heat thermode. There was a direct correlation between the reduction in total plasma TRP levels and reduction in thermode temperature. In contrast, ATD showed no effect on laser-induced pain nor significant impact of the distraction-induced analgesia on pain perception but did reduce performance of the painful temperature discrimination task. Importantly, all findings were independent of any effects of ATD on mood.

CONCLUSION

As far as we are aware, it is the first demonstration of 5-HT effects on pain perception which are not confounded by mood changes.

Gender differences in depression and pain: A two year follow-up study of the Survey of Health, Ageing and Retirement in Europe

BACKGROUND

The longitudinal association of depression and pain according to gender was investigated using a population-based sample from 13 European countries.

METHODS

The study population was taken from waves 4-5 of the Survey of Health, Ageing and Retirement in Europe. The sample consisted of 22,280 participants ≥50 years, who were interviewed at baseline, and after two years. Regression models for each gender were used to assess the variables associated with depression and pain incidence and persistence.

RESULTS

Prevalences of depression, pain, and depression-pain co-occurrence, were higher in women than in men (depression: 34.5% vs. 20.3%; OR=2.1; 95% CI=1.9-2.2; pain: 60.2% vs. 53.5%; OR=1.3; 95% CI=1.2-1.4; co-occurrence 25.3% vs. 14.0%; OR=2.3; 95% CI=2.2-2.6). Treated baseline pain in women (OR=1.6; 95% CI=1.3-2.0), and treated/untreated pain in men (untreated OR=1.3; 95% CI=1.1-1.7; treated OR=2.0; 95% CI=1.5-2.7), were associated with incident depression. Untreated baseline depression was associated with incident pain (women OR=1.3; 95% CI=1.1-1.7; men OR=1.8; 95% CI=1.3-2.6), and with persistent pain only in women (OR=1.3; 95% CI=1.1-1.6).

LIMITATIONS

We lack information on pain severity, and the consumption of analgesics was used as a proxy. We lack information on antidepressants and anxiolytics consumption separately. Participants were interviewed twice in two years, and pain/depression at both interviews were considered persistent although they may have relapsed and recurred.

CONCLUSIONS

Treated baseline pain is a risk factor for incident depression in both genders; untreated baseline pain is a risk factor only in men. Treating depression at baseline may protect from developing pain in both genders, and in women, it may also protect from pain persistence.

CLASSIFICATION OF ANXIETY DISORDERS COMORBID WITH MAJOR DEPRESSION: COMMON OR DISTINCT INFLUENCES ON RISK?

BACKGROUND

Anxiety and depression display frequent comorbidity. Individuals with comorbid disorders also often have more extreme symptomatology than those with single disorders. This correlation between comorbidity and severity poses an interesting question: Are comorbid forms of anxiety and depression essentially just more severe versions of the pure disorders?

METHODS

In a large major depression (MD) case-control sample of individuals from the China, Oxford and VCU Experimental Research on Genetic Epidemiology project, we examined the patterns of lifetime anxiety comorbidity (including generalized anxiety disorder--GAD, panic disorder, and five phobia subtypes) among MD cases (N = 5,864) in this population. Binary and multinomial logistic regression was used to estimate associations between risk factors and outcomes including MD as well as latent class membership, which were compared using continuation ratios.

RESULTS

We found a five-class solution to fit best, and each resulting class had a distinct pattern of association with the tested risk factors. The use of continuation ratios suggests that a class characterized by high endorsement of GAD is comparable to a more severely affected "pure MD" group. The other three classes (characterized by agoraphobia, various specific phobias, and by high endorsement of all comorbid anxiety disorders, respectively) appear to differ meaningfully from MD alone.

CONCLUSIONS

Risk for MD resulting from environmental and psychosocial factors may also predispose individuals to GAD, and less consistently, other anxiety disorders. Presentations of MD with certain phobias display distinguishably different patterns of risk, however, and are therefore likely qualitatively distinct.

The Role of Regulatory Transporters in Neuropathic Pain

Neuropathic pain arises from an injury or disease of the somatosensory nervous system rather than stimulation of pain receptors. As a result, the fine balance between excitation and inhibition is perturbed leading to hyperalgesia and allodynia. Various neuropathic pain models provide considerable evidence that changes in the glutamatergic, GABAergic, and monoaminergic systems. Neurotransmitter reuptake transporter proteins have the potential to change the temporal and spatial profile of various neurotransmitters throughout the nervous system. This, in turn, can affect the downstream effects of these neurotransmitters and hence modulate pain. This chapter explores various reuptake transporter systems and implicates their role in pain processing. Understanding the transporter systems will enhance drug discovery targeting different facets of neuropathic pain.

Psychopharmacology of chronic pain: a focus on antidepressants and atypical antipsychotics

Chronic pain is considered one of the most prevalent causes of costly and disabling medical conditions. This review will define chronic pain and its categories and then will summarize the effectiveness and side effects associated with the use of various antidepressants, including the tricyclics, the selective serotonin reuptake inhibitors, the serotonin norepinephrine reuptake inhibitors, other miscellaneous antidepressants and the atypical antipsychotics in the treatment of chronic pain.

Experimental pain sensitivity in subjects with major depression: Many pain complaints without hypersensitivity

OBJECTIVE

Patients with major depression frequently complain of pain, but conflicting data exist concerning their changes in pain sensitivity. This study aimed at comparing the sensitivity to moderate controlled pain between subjects presenting a major depressive episode (isolated and recurrent depressive episodes or a bipolar disorder), controls, and subjects with schizophrenia from a previous study.

METHOD

Pain sensitivity was assessed obtaining the visual analog scale (VAS) rating for the application of a 160 kPa pre-fixed pressure (fpVAS), the pressure corresponding to a VAS score of 3, and the time required to achieve a VAS score of 3 during ischemia induction. The effects of depression intensity, alexithymia, current and past general pain, and of six weeks of antidepressant treatment on fpVAS were investigated.

RESULTS

The results did not differ significantly between the depressed groups and the controls, without any effect of depression intensity. Presence of long-lasting pain and current pain felt on the day of testing correlated with fpVAS. The subjects of the depressed group were less sensitive than subjects with schizophrenia. FpVAS was significantly lower before and after antidepressant treatment in the subjects presenting clinical improvement.

CONCLUSIONS

No difference in experimental pain sensitivity and expression between major depressive episode subjects and controls, in opposite to pain complaints, is to be detected. The changes in the sensation of pain routinely attributed to subjects presenting depression may result from changes in a differential processing of pain signals, not in relation with the depression intensity, or the kind of depressive disorder.

Self-system therapy for distress associated with persistent low back pain: A randomized clinical trial

OBJECTIVE

Persistent low back pain (PLBP) is associated with vulnerability to depression. PLBP frequently requires major changes in occupation and lifestyle, which can lead to a sense of failing to attain one's personal goals (self-discrepancy).

METHOD

We conducted a clinical trial to examine the efficacy of self-system therapy (SST), a brief structured therapy for depression based on self-discrepancy theory. A total of 101 patients with PLBP and clinically significant depressive symptoms were randomized either to SST, pain education, or standard care.

RESULTS

Patients receiving SST showed significantly greater improvement in depressive symptoms. Reduction in self-discrepancy predicted reduction in depressive symptoms only within the SST condition.

CONCLUSIONS

Findings support the utility of SST for individuals facing persistent pain and associated depression.

Pain and depression: a neurobiological perspective of their relationship

Remarkable progresses have been achieved regarding the understanding of the neurobiological bases of pain and depression. The principal role of neurotransmitters, neuromodulators, and neurohormones has been proposed in the development of pain and depression. With the progression of molecular biology, an intricate interaction among biological factors accountable to the development and management of pain and depression has been also shown in a numerous preclinical and clinical researches. This mini-review will briefly describe the current issues and future research direction for better understanding of the relationship between pain and depression.

Predictors of remission in the treatment of major depressive disorder: real-world evidence from a 6-month prospective observational study

BACKGROUND

This study examined potential predictors of remission among patients treated for major depressive disorder (MDD) in a naturalistic clinical setting, mostly in the Middle East, East Asia, and Mexico.

METHODS

Data for this post hoc analysis were taken from a 6-month prospective, noninterventional, observational study that involved 1,549 MDD patients without sexual dysfunction at baseline in 12 countries worldwide. Depression severity was measured using the Clinical Global Impression of Severity and the 16-item Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR16). Depression-related pain was measured using the pain-related items of the Somatic Symptom Inventory. Remission was defined as a QIDS-SR16 score ≤5. Generalized estimating equation regression models were used to examine baseline factors associated with remission during follow-up.

RESULTS

Being from East Asia (odds ratio [OR] 0.48 versus Mexico; P<0.001), a higher level of depression severity at baseline (OR 0.77, P=0.003, for Clinical Global Impression of Severity; OR 0.92, P<0.001, for QIDS-SR16), more previous MDD episodes (OR 0.92, P=0.007), previous treatments/therapies for depression (OR 0.78, P=0.030), and having any significant psychiatric and medical comorbidity at baseline (OR 0.60, P<0.001) were negatively associated with remission, whereas being male (OR 1.29, P=0.026) and treatment with duloxetine (OR 2.38 versus selective serotonin reuptake inhibitors, P<0.001) were positively associated with remission. However, the association between Somatic Symptom Inventory pain scores and remission no longer appeared to be significant in this multiple regression (P=0.580), (P=0.008 in descriptive statistics), although it remained significant in a subgroup of patients treated with selective serotonin reuptake inhibitors (OR 0.97, P=0.023), but not in those treated with duloxetine (P=0.182).

CONCLUSION

These findings are largely consistent with previous reports from the USA and Europe. They also highlight the potential mediating role of treatment with duloxetine on the negative relationship between depression-related pain and outcomes of depression.

Therapeutic potential of inhibitors of endocannabinoid degradation for the treatment of stress-related hyperalgesia in an animal model of chronic pain

The occurrence of chronic stress, depression, and anxiety can increase nociception in humans and may facilitate the transition from localized to chronic widespread pain. The mechanisms underlying chronic widespread pain are still unknown, hindering the development of effective pharmacological therapies. Here, we exposed C57BL/6J mice to chronic unpredictable stress (CUS) to investigate how persistent stress affects nociception. Next, mice were treated with multiple intramuscular nerve growth factor (NGF) injections, which induced chronic widespread nociception. Thus, combination of CUS and NGF served as a model where psychophysiological impairment coexists with long-lasting hyperalgesia. We found that CUS increased anxiety- and depression-like behavior and enhanced basal nociception in mice. When co-applied with repeated NGF injections, CUS elicited a sustained long-lasting widespread hyperalgesia. In order to evaluate a potential therapeutic strategy for the treatment of chronic pain associated with stress, we hypothesized that the endocannabinoid system (ECS) may represent a target signaling system. We found that URB597, an inhibitor of the anandamide-degrading enzyme fatty acid amide hydrolase (FAAH), and JZL184, an inhibitor of the 2-arachidonoyl glycerol-degrading enzyme monoacylglycerol lipase (MAGL), increased eCB levels in the brain and periphery and were both effective in reducing CUS-induced anxiety measured by the light-dark test and CUS-induced thermal hyperalgesia. Remarkably, the long-lasting widespread hyperalgesia induced by combining CUS and NGF was effectively reduced by URB597, but not by JZL184. Simultaneous inhibition of FAAH and MAGL did not improve the overall therapeutic response. Therefore, our findings indicate that enhancement of anandamide signaling with URB597 is a promising pharmacological approach for the alleviation of chronic widespread nociception in stress-exposed mice, and thus, it could represent a potential treatment strategy for chronic pain associated with neuropsychiatric disorders in humans.

Depression and pain impair daily functioning and quality of life in patients with major depressive disorder

BACKGROUND

Depression and pain frequently occur together. The objective of this study was to investigate the effects of depression and pain on the impairment of daily functioning and quality of life (QOL) of depressed patients.

METHODS

We enrolled 131 acutely ill inpatients with major depressive disorder. Depression, pain, and daily functioning were assessed using the 17-item Hamilton Depression Rating Scale, the Short-Form 36 (SF-36) Body Pain Index, and the Work and Social Adjustment Scale. Health-related QOL was assessed using three primary domains of the SF-36: social functioning, vitality, and general health perceptions. Pearson׳s correlation and structural equation modeling were used to examine relationships among the study variables. Five models were proposed.

RESULTS

In all, 129 patients completed all the measures. Model 5, both depression and pain impaired daily functioning and QOL, was the most fitted structural equation model (χ(2)=9.2, df=8, p=0.33, GFI=0.98, AGFI=0.94, TLI=0.99, CFI=0.99, RMSEA=0.03). The correlation between pain and depression was weak (r=-0.27, z=-2.95, p=0.003).

LIMITATION

This was a cross-sectional study with a small sample size.

CONCLUSION

Depression and pain exert a direct influence on the impairment of daily functioning and QOL of depressed patients; this impairment could be expected regardless of increased pain, depression, or both pain and depression. Pain had a somewhat separate entity from depression.

The use of non-narcotic pain medication in pediatric gastroenterology

The perception of pain in children is easily influenced by environmental factors and psychological comorbidities that are known to play an important role in its origin and response to therapy. Chronic abdominal pain is one of the most commonly treated conditions in modern pediatric gastroenterology and is the hallmark of 'functional' disorders that include irritable bowel syndrome, functional dyspepsia, and functional abdominal pain. The development of pharmacological therapies for these disorders in adults and children has been limited by the lack of understanding of the putative, pathophysiological mechanisms that underlie them. Peripheral and central pain-signaling mechanisms are known to be involved in chronic pain originating from the gastrointestinal tract, but few therapies have been developed to target specific pathways or enhance correction of the underlying pathophysiology. The responses to therapy have been variable, potentially reflecting the heterogeneity of the disorders for which they are used. Only a few small, randomized clinical trials have evaluated the benefit of pain medications for chronic abdominal pain in children and thus, the decision on the most appropriate treatment is often based on adult studies and empirical data. This review discusses the most common, non-narcotic pharmacological treatments for chronic abdominal pain in children and includes a thorough review of the literature to support or refute their use. Because of the dearth of pediatric studies, the focus is on pharmacological and alternative therapies where there is sufficient evidence of benefit in either adults or children with chronic abdominal pain.

Effects of sertraline on executive function and quality of life in patients with advanced cancer

Background

The aim of this study was to investigate effects of the antidepressant sertraline on executive function and quality of life in patients with advanced cancer.

Material/Methods

We assigned 122 patients with stage III or IV cancer to the depressed group (DG, n=86) or the non-depressed group (NG, n=36). All subjects were given supportive treatment and patients in the DG received additional antidepressant treatment.

Results

There were significant differences in total scores of the Hamilton anxiety scale (HAMA) and the Hamilton depression scale (HAMD), performance in the Wisconsin card sorting test, and SF-36 domains. After antidepressant treatment, the level of depression and anxiety decreased significantly in the DG, but was still significantly higher than in the NG. Low executive function was enhanced in the DG, but a worsening executive function was found in total errors in the NG (−2.3±3.8) (P<0.05). The dimensions of SF-36 in physical functioning (PF), role limitations-physical (RP), bodily pain (BP), general health (GH), vitality (VT), social functioning (SF), role limitations-emotional (RE), and mental health (MH) were decreased significantly at baseline in the DG compared to the NG (P<0.01). After 12-week Sertraline treatment, improvement in the DG in factors VT, SF, RE, and MH were more powerful than in the NG (P<0.05). HAMA, HAMD, and VAS scores and tumor stage were significantly correlated to any one dimension of quality of life.

Conclusions

Depression is an important cause of decreased quality of life and executive function in patients with advanced cancer. The antidepressant sertraline can improve the executive function and quality of life, which may be helpful in the clinical practice of cancer treatment.

Ectoparasitic sea lice (Lepeophtheirus salmonis) affect behavior and brain serotonergic activity in Atlantic salmon (Salmo salar L.): Perspectives on animal welfare

Scientific research and public debate on the welfare of animals in human custody is increasing at present. Fish are in this context mentioned with particular attention to the high numbers of individuals reared in aquaculture. Research on fish has also contributed to the understanding of individual variation in the ability to cope with stress and disease. One mediator of such variation is the brain serotonergic (5-hydroxytryptamine, 5-HT) system, which conveys physiological and behavioral responses to stress and sub-optimal rearing conditions. Here we study links between the 5-HT response, melanin-based skin pigmentation, and behavior in laboratory-reared Atlantic salmon (Salmo salar) experimentally infested with ectoparasitic sea lice (Lepeophtheirus salmonis). Lice numbers were more variable in less pigmented fish, while the neurochemical response to ectoparastic lice-increased levels of the main 5-HT catabolite 5-HIAA in the brain stem-did not differ between pigmentation groups. A strong depression of growth and locomotor activity was seen in all infested fish but less pigmented fish grew better than fish with more skin melanization regardless of infestation status. The observed combination of neurochemical and behavioral effects clearly suggest that animal welfare concerns can be added to the list of negative effects of ectoparasitic sea lice.