Common mechanisms of pain and depression: are antidepressants also analgesics?

Molecular mechanisms of Schisandra chinensis in treating depression-neuropathic pain comorbidity by network pharmacology and molecular docking analysis

This study utilized network pharmacology and docking analyses to explore a groundbreaking therapeutic approach for managing the neuropathic pain and depressive disorder (NP/DD) comorbidity. Schisandra chinensis (SC), a common Chinese medicine, has demonstrated numerous beneficial effects in treating neuropsychological disorders. The main objective of this study was to identify potential bioactive components of SC and investigate their interactions with relevant target genes associated with NP/DD. To gain insights into the underlying molecular mechanisms, GO and KEGG analyses were conducted. Furthermore, molecular docking analysis was employed to validate the therapeutic relevance of SC's active ingredients. Seven bioactive components of SC, namely Longikaurin A, Deoxyharringtonine, Angeloylgomisin O, Schisandrin B, Gomisin A, Gomisin G, and Gomisin R, exhibited effectiveness in the treatment of NP/DD. From this list, the first five components were selected for further analysis. The analyses revealed a complex network of interactions between the targets of SC and NP/DD, providing valuable information about the molecular mechanisms involved in the treatment of NP/DD with SC. SC components demonstrated the ability to regulate pathways involving tumor necrosis factor (TNF), vascular endothelial growth factor (VEGF), and other growth hormones (GH). Overall, this study contributes to our understanding of the molecular mechanisms underlying the effects of SC in treating NP/DD. Further investigation is necessary to explore the therapeutic potential of SC as a viable strategy for NP/DD comorbidity. These findings lay a solid foundation for future research endeavors in this field, holding potential implications for the development of novel therapeutic interventions targeting NP/DD.

Alterations in metabolites in the anterior cingulate cortex and thalamus and their associations with pain and empathy in patients with chronic mild pain: a preliminary study

Proton magnetic resonance spectroscopy (1H-MRS) has shown inconsistent alterations in the brain metabolites of individuals with chronic pain. We used 3T 1H-MRS to investigate the brain metabolites in the anterior cingulate cortex and thalamus of 22 patients with chronic mild pain and no gait disturbance and 22 healthy controls. The chronic-pain group included patients with chronic low back pain and/or osteoarthritis but none suffering from hypersensitivity. There were no significant between group-differences in glutamate, glutamate plus glutamine (Glx), N-acetylaspartate, glycerophosphorylcholine (GPC), glutamine, creatine plus phosphocreatine, or myo-inositol in the anterior cingulate cortex, but the patients showed a significant decrease in GPC, but not other metabolites, in the thalamus compared to the controls. The GPC values in the patients' thalamus were significantly correlated with pain components on the Short-Form McGill Pain Questionnaire (SF-MPQ-2) and affective empathy components on the Questionnaire of Cognitive and Affective Empathy (QCAE). The GPC in the patients' anterior cingulate cortex showed significant correlations with cognitive empathy components on the QCAE. Myo-inositol in the controls' anterior cingulate cortex and Glx in the patients' thalamus each showed significant relationships with peripheral responsivity on the QCAE. These significances were not significant after Bonferroni corrections. These preliminary findings indicate important roles of GPC, myo-inositol, and Glx in the brain of patients with chronic mild pain.

The unmet mental health needs of U.S. adults living with chronic pain

ABSTRACT

Previous research suggests that individuals with mental health needs and chronic pain may be less likely to use mental health treatment compared with those with mental health needs only. Yet, few studies have investigated the existence of population-level differences in mental health treatment use. We analyzed data from the National Health Interview Survey (n = 31,997) to address this question. We found that chronic pain was associated with end-to-end disparities in the mental health journeys of U.S. adults: (1) Those living with chronic pain are overrepresented among U.S. adults with mental health needs; (2) among U.S. adults with mental health needs, those living with chronic pain had a lower prevalence of mental health treatment use; (3) among U.S. adults who used mental health treatment, those living with chronic pain had a higher prevalence of screening positive for unremitted anxiety or depression; (4) among U.S. adults living with both chronic pain and mental health needs, suboptimal mental health experiences were more common than otherwise-just 44.4% of those living with mental health needs and co-occurring chronic pain reported use of mental health treatment and screened negative for unremitted anxiety and depression, compared with 71.5% among those with mental health needs only. Overall, our results suggest that U.S. adults with chronic pain constitute an underrecognized majority of those living with unremitted anxiety/depression symptoms and that the U.S. healthcare system is not yet adequately equipped to educate, screen, navigate to care, and successfully address their unmet mental health needs.

Co-occurrence of chronic pain and anxiety/depression symptoms in U.S. adults: prevalence, functional impacts, and opportunities

ABSTRACT

Co-occurrence of chronic pain and clinically significant symptoms of anxiety and/or depression is regularly noted in the literature. Yet, little is known empirically about population prevalence of co-occurring symptoms, nor whether people with co-occurring symptoms constitute a distinct subpopulation within US adults living with chronic pain or US adults living with anxiety and/or depression symptoms (A/D). To address this gap, this study analyzes data from the 2019 National Health Interview Survey, a representative annual survey of self-reported health status and treatment use in the United States (n = 31,997). Approximately 12 million US adults, or 4.9% of the adult population, have co-occurring chronic pain and A/D symptoms. Unremitted A/D symptoms co-occurred in 23.9% of US adults with chronic pain, compared with an A/D prevalence of 4.9% among those without chronic pain. Conversely, chronic pain co-occurred in the majority (55.6%) of US adults with unremitted A/D symptoms, compared with a chronic pain prevalence of 17.1% among those without A/D symptoms. The likelihood of experiencing functional limitations in daily life was highest among those experiencing co-occurring symptoms, compared with those experiencing chronic pain alone or A/D symptoms alone. Among those with co-occurring symptoms, 69.4% reported that work was limited due to a health problem, 43.7% reported difficulty doing errands alone, and 55.7% reported difficulty participating in social activities. These data point to the need for targeted investment in improving functional outcomes for the nearly 1 in 20 US adults living with co-occurring chronic pain and clinically significant A/D symptoms.

Assessing Dose- and Sex-Dependent Antinociceptive Effects of Cannabidiol and Amitriptyline, Alone and in Combination, and Exploring Mechanism of Action Involving Serotonin 1A Receptors

Inflammatory pain is caused by tissue hypersensitization and is a component of rheumatic diseases, frequently causing chronic pain. Current guidelines use a multimodal approach to pain and sociocultural changes have renewed interest in cannabinoid use, particularly cannabidiol (CBD), for pain. The tricyclic antidepressant amitriptyline (AT) is approved for use in pain-related syndromes, alone and within a multimodal approach. Therefore, we investigated sex- and dose-dependent effects of CBD and AT antinociception in the 2.5% formalin inflammatory pain model. Male and female C57BL/6J mice were pretreated with either vehicle, CBD (0.3-100 mg/kg), or AT (0.1-30 mg/kg) prior to formalin testing. In the acute phase, CBD induced antinociception after administration of 30-100 mg/kg in males and 100 mg/kg in females and in the inflammatory phase at doses of 2.5-100 mg/kg in males and 10-100 mg/kg in females. In the acute phase, AT induced antinociception at 10 mg/kg for all mice, and at 0.3 mg/kg in males and 3 mg/kg in female mice in the inflammatory phase. Combining the calculated median effective doses of CBD and AT produced additive effects for all mice in the acute phase and for males only in the inflammatory phase. Use of selective serotonin 1A receptor antagonist N-[2-[4-(2-methoxyphenyl)-1 piperazinyl]ethyl]-N-2-pyridinylcyclohexanecarboxamide (WAY-100635) maleate (0.1 mg/kg) before co-administration of CBD and AT reversed antinociception in the acute and partially reversed antinociception in the inflammatory phase. Administration of AT was found to enhance cannabinoid receptor type 1mRNA expression only in female mice. These results suggest a role for serotonin and sex in mediating cannabidiol and amitriptyline-induced antinociception in inflammatory pain. SIGNIFICANCE STATEMENT: Inflammatory pain is an important component of both acute and chronic pain. We have found that cannabidiol (CBD) and amitriptyline (AT) show dose-dependent, and that AT additionally shows sex-dependent, antinociceptive effects in an inflammatory pain model. Additionally, the combination of CBD and AT was found to have enhanced antinociceptive effects that is partially reliant of serotonin 1A receptors and supports the use of CBD within a multimodal approach to pain.

Post cerebral venous thrombosis headache - Prevalence, mechanisms and risk factors

INTRODUCTION

Headache after cerebral venous thrombosis (post-CVT headache [PCH]) is a common complaint during follow-up. Risk factors and their pathophysiology are not well known. We studied PCH prevalence in CVT patients, its pathophysiology, and possible risk factors.

MATERIALS AND METHODS

We performed a retrospective observational study of patients admitted to a tertiary hospital between 2006 and 2019 with CVT and at least one follow-up appointment. We diagnosed PCH when patients reported headaches during the follow-up visit. Recanalization was retrospectively assessed by two neuroradiologists using the first available follow-up MRI/ MRV, and the PRIORITy-CVT study classification.

RESULTS

Of 131 patients, sixty (60/131, 45.8 %) reported PCH at the 3-month follow-up. Of these PCH, 9 had previous migraine (9/60, 5.0 %) and 13 previous tension-type headaches (13/60, 21.6 %), before CVT. Forty-four (44/60, 73.3 %) PCH patients had de novo headache: 21 (21/60, 35.0 %) de novo tension-type headaches; 6 (6/60, 10.0 %) de novo migraine; 6 [(6/60, 10.0 %) secondary headache disorders: 3 due to dural arteriovenous fistula, 2 due to intracranial hypertension, and 1 recurrent CVT], and 11 other headache types. Most patients had at least partial recanalization, with no difference in PCH frequency amongst recanalization subgroups (p = 0.598). Premorbid depression (p = 0.009, OR 7.9, 95 % CI 1.6-31.4) increased the odds ratio of PCH, while superior sagittal sinus thrombosis (p = 0.005, OR 0.15, 95 % CI 0.03-0.56) decreased it.

DISCUSSION

Our study shows that PCH is a common finding after CVT and elucidates potential risk factors. PCH is common in patients with previous or de novo primary headache. In PCH patients without previous headache, secondary causes of headache, namely related to CVT complications, should be excluded. PCH is also increased in patients with premorbid depression. There was no statistically significant difference in PCH amongst the PRIORITy-CVT recanalization subgroups, but most patients had at least partial recanalization.

Differences in risk factors for flare-ups in patients with lumbar radicular pain may depend on the definition of flare

OBJECTIVES

The objective was to determine whether specific physical activity (PA) or psychological stress factors are associated with different definitions of flare-ups (pain-defined flares [PDFs]: periods of increased pain lasting at least 2 h, when pain intensity is distinctly worse than it has been recently; and non-pain-defined flares [NPDFs]: obviously uncomfortable feelings, such as fatigue, loss of function, or emotional/psychosocial fluctuations, without major fluctuations in pain intensity based on 11-point scales) among people with lumbar radicular pain.

METHODS

This was a case-crossover study. Participants with acute or subacute lumbar radicular pain completed serial face-to-face or online assessments for 6 weeks at 3-day intervals to determine whether they experienced sciatica flare-ups (PDF/NPDF) after specific types of PA or psychological stresses.

RESULTS

A total of 152 participants were enroled. There were 597 PDF and 323 NPDF case periods and 800 control periods. The odds of PDFs were increased by prolonged walking and standing, and the odds of NPDFs were increased by prolonged sitting, mental distress, and depressed mood. According to the multivariable analyses, prolonged sitting (OR: 3.0, 95% CI: 1.7-5.5), prolonged walking (OR: 6.2, 95% CI: 3.9-9.9), and prolonged standing (OR: 5.6, 95% CI: 3.3-9.5) were significantly associated with the odds of PDFs, and prolonged sitting (OR: 3.4, 95% CI: 1.8-6.2), mental distress (OR: 6.7, 95% CI: 2.5-17.5), and depressed mood (OR: 5.8, 95% CI: 2.6-12.8) associated with the odds of NPDFs.

CONCLUSIONS

Prolonged sitting, walking, and standing triggered the occurrence of PDF. Prolonged sitting, mental distress, and depressed mood triggered the occurrence of NPDF.

Hemokinin-1 is a mediator of chronic restraint stress-induced pain

The Tac4 gene-derived hemokinin-1 (HK-1) binds to the NK1 receptor, similarly to Substance P, and plays a role in acute stress reactions and pain transmission in mice. Here we investigated Tac4 mRNA expression in stress and pain-related regions and its involvement in chronic restraint stress-evoked behavioral changes and pain using Tac4 gene-deleted (Tac4-/-) mice compared to C57Bl/6 wildtypes (WT). Tac4 mRNA was detected by in situ hybridization RNAscope technique. Touch sensitivity was assessed by esthesiometry, cold tolerance by paw withdrawal latency from 0°C water. Anxiety was evaluated in the light-dark box (LDB) and open field test (OFT), depression-like behavior in the tail suspension test (TST). Adrenal and thymus weights were measured at the end of the experiment. We found abundant Tac4 expression in the hypothalamic-pituitary-adrenal axis, but Tac4 mRNA was also detected in the hippocampus, amygdala, somatosensory and piriform cortices in mice, and in the frontal regions and the amygdala in humans. In Tac4-/- mice of both sexes, stress-induced mechanical, but not cold hyperalgesia was significantly decreased compared to WTs. Stress-induced behavioral alterations were mild or absent in male WT animals, while significant changes of these parameters could be detected in females. Thymus weight decrease can be observed in both sexes. Higher baseline anxiety and depression-like behaviors were detected in male but not in female HK-1-deficient mice, highlighting the importance of investigating both sexes in preclinical studies. We provided the first evidence for the potent nociceptive and stress regulating effects of HK-1 in chronic restraint stress paradigm. Identification of its targets might open new perspectives for therapy of stress-induced pain.

Antidepressant effects of coumarins and their derivatives: A critical analysis of research advances

Coumarins and their derivatives are non-flavonoids polyphenols with diverse pharmacological activities including anti-depressant effects. This study systematically examines the antidepressant effects of coumarins and their derivatives in relation to time series of research progress in the pharmacological pathways, association with other diseases, toxicity and bibliometric analysis. The review was approached using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) coupled with R package involving Biblioshiny, a web interface for Bibliometrix analysis and VOSviewer software analytic tools. Literature searches were conducted in Scopus, Web of Science, and PubMed from the inception through January 21, 2023. Coumarins, depression, coumarin derivatives and treatment were the main search terms used which resulted in the inclusion of 46 eligible publications. Scopoletin, psoralen, 7-hydroxycoumarin, meranzin hydrate, osthole, esculetin/umbelliferone were the most studied coumarins with antidepressant effects. Coumarins and their derivatives exerted antidepressant effects with a stronger affinity for monoamine oxidase-B (MAO-B) inhibition and, their inhibitory effect via neurotransmitter pathway on MAO is well-studied. However, epigenetic modification, neuroendocrine, neurotrophic pathways are understudied. Recent research focuses on their antidepressant effects which targeted cytokines and fibromyalgia. There is a link between the gut microbiome, the brain, and depression; meranzin hydrate exerts an antidepressant activity by remodelling the gastrointestinal system. We established that empirical data on some coumarins and their derivatives to support their antidepressant effects are limited. Likewise, the safe dose range for several coumarins and their derivatives is yet to be fully determined.

Pain and Associated Factors in Nursing Home Residents

BACKGROUND

Understanding factors associated with risk of pain allows residents and clinicians to plan care and set priorities, however, factors associated with pain in nursing home residents has not been conclusively studied.

AIM

To evaluate the association between pain and nursing home (NH) resident demographic and clinical characteristics.

DESIGN

Retrospective analysis of Minimum Data Set 3.0 records of nursing home residents residing in 44 Indiana NHs between September 27, 2011 and December 27, 2019 (N = 9,060).

RESULTS

Pain prevalence in this sample of NH residents was 23.7%. Of those with pain, 28.0% experienced moderate to severe/frequent pain and 54.6% experienced persistent pain. Risk factors for moderate to severe/frequent pain include female sex; living in a rural setting; intact, mildly, or moderately impaired cognition; arthritis; contracture; anxiety; and depression. In contrast, stroke and Alzheimer's disease and Alzheimer's-disease related dementias (AD/ADRD) were associated with decreased risk of reporting moderate to severe/frequent pain, likely representing both the under-assessment and under-reporting of pain among cognitively impaired NH residents. Risk factors for persistent pain included age <70, Black race, living in a rural location, intact cognition, contracture, and depression.

CONCLUSIONS

Pain remains a pressing problem for NH residents. In this study, we identified demographic and clinical factors associated with moderate to severe frequent pain and persistent pain. Residents with a diagnosis of AD/ADRD were less likely to report pain, likely representing the difficulty of evaluating pain in these residents. It is important to note that those with cognitive impairment may not experience any less pain, but assessment and reporting difficulties may make them appear to have less pain. Knowledge of factors associated with pain for NH residents has the potential for improving the ability to predict, prevent, and provide better pain care in NH residents.

Objective Evaluation of Chronic Low-Back Pain Using Serum Lipids: The Role of the Doctor-Patient Relationship

Statistical data show that pain intensity in patients with low back pain is associated with a higher BMI, total serum cholesterol, and triacylglycerol levels. The objective of our study was to evaluate how these associations are dependent on the nature of the patient-doctor relationship. Eighty-nine patients hospitalized with chronic low-back pain (50 women, 39 men; average age: 64.5 ± 12.7 years) were assessed over a 3-year period. A serum lipid analysis was conducted (LDL-C, HDL-C, and total cholesterols) at admission in parallel with a subjective evaluation of pain intensity, which was assessed using a numeric rating scale. The participating physician assigned, based on their personal interaction with the patient, an attribute of affinity (positive, neutral, and negative) towards them. Current serum lipid levels and pain intensity were correlated relative to these attributes. Pain intensity did not differ between the groups assigned positive or negative attributes of affinity. In patients belonging to the “positive” group, pain intensity correlated positively with total cholesterol ( $p=0.01$ ) and LDL cholesterol ( $p=0.007$ ). No correlations were found in the “negative” group or when the patient-doctor relationship was ignored. We found a significant association between subjectively assessed low back pain intensity and serum levels of total and LDL cholesterol in patients with whom the physician had a positive affinity. A positive affinity with the patients having chronic pain and the patient’s trust in their physicians may ultimately mean that the patient’s statement about pain is more credible, which may retroactively affect the outcome of therapy.

Comparison of the clinical effectiveness of treatments for aromatase inhibitor-induced arthralgia in breast cancer patients: A systematic review with network meta-analysis

Aromatase inhibitor-induced arthralgia (AIA) contributes to poor adherence of aromatase inhibitor therapies in patients with breast cancer. A systematic review using network meta-analysis (NMA) was conducted to examine the clinical effectiveness of multiple therapies and rank probabilities for the management of AIA. Randomized controlled trials (RCTs) assessing treatments for AIA in postmenopausal women with stage 0-III hormone receptor-positive breast cancer were searched from inception to October 2021. The main NMA involved 1516 participants from 17 RCTs. Acupuncture was the highest ranked intervention to improve pain intensity followed by sham acupuncture, multicomponent herbal medicine, exercise, duloxetine, vitamin D, omega-3 fatty acids, physical therapy, testosterone, and inactive controls. Single natural products were inferior to controls. The current review provides new insights into the management of AIA in breast cancer survivors for increased survival and can be utilized to make evidence-based decisions regarding treatment.

Screening key genes related to neuropathic pain-induced depression through an integrative bioinformatics analysis

Background

Neuropathic pain (NP) is often accompanied by sleep disorders, anxiety, depression and other complications, and the pathogenesis is still unclear. Some drugs can relieve patients' pain, but the overall effect is not good. We screened for the key genes related to NP-induced depression based on bioinformatics.

Methods

The dataset of GSE92718 was obtained from the Gene Expression Omnibus database, data mining was conducted based on R language, the genes modules were screened by weighted correlation network analysis, Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed, a protein-protein interaction (PPI) network was constructed in the STRING database, and hub genes were screened according to degree value.

Results

Seven modules were obtained and built to identify the relationships between the NP-induced depression and the modules, weighted gene co-expression network analysis (WGCNA) was used to identify gene modules closely related to the experimental group. The GO annotations of depression-related genes mainly enriched in protein polyubiquitination, regulation of chromosome organization, mitochondrial matrix, mitochondrial protein-containing complex, etc. KEGG enrichment analysis results were: Alzheimer's disease, Huntington's disease, ribosome, thermogenesis, prion disease, non-alcoholic fatty liver disease, diabetic cardiomyopathy, oxidative phosphorylation, retrograde endocannabinoid signaling, 2-oxocarboxylic acid metabolism. PPI network analysis showed that Polr2f, Rps13, Mrpl2, Mrpl40, Mrpl34, and Ndufs8 were more highly expressed in NP-induced depression. Functional analysis of key genes showed that these genes were related to mitochondrial translation termination, respiratory chain complex I, mitochondrial, mRNA Splicing (minor pathway), and of rRNA processing in the nucleolus and cytosol (major pathway).

Conclusions

The key genes of depression induced by NP are Polr2f, Rps13, Mrpl2, Mrpl40, Mrpl34, and Ndufs8.

Prevalence and Factors Associated with Pain in Nursing Home Residents: A Systematic Review of the Literature

OBJECTIVES

To describe the pain prevalence in nursing home (NH) residents and the factors associated with the experience of pain.

DESIGN

Systematic review of descriptive studies.

SETTING AND PARTICIPANTS

Three electronic databases were searched from 2010 to September 2020 in English. Descriptive studies that examined pain in NH residents, reported pain prevalence, and/or associated factors were included. Studies that focused exclusively on a specific disease or type of care such as cancer or hospice were excluded.

METHODS

Two reviewers independently screened, selected, extracted data, and assessed risk of bias from included studies; narrative synthesis was performed. The review was guided by the Biopsychosocial Model of Chronic Pain for Older Adults.

RESULTS

Twenty-six studies met our inclusion criteria. Overall, the prevalence of current pain ranged from 22.2% to 85.0%, the prevalence of persistent pain ranged from 19.5% to 58.5%, and the prevalence of chronic pain ranged from 55.9% to 58.1%. A variety of pain scales were used reporting higher pain prevalence for those using self-report measures (31.8% to 78.8%) or proxy measures (29.5% to 85.0%) compared with using chart review (22.2% to 29.3%) as the source of pain information. The studies reviewed provide support that certain diseases and clinical conditions are associated with pain. Impairment in activities of daily living (ADL) (12 studies), cognition (9 studies), depression (9 studies), and arthritis (9 studies) are the most widely studied factors, whereas depression, ADL impairment, arthritis, dementia, and cognitive impairment present the strongest association with pain.

CONCLUSION AND IMPLICATIONS

This review highlights the complexities of pain in NH residents and has implications for both clinical practice and future research. Understanding the factors that underlie the experience of pain, such as depression, is useful for clinicians evaluating pain and tailoring management therapies. In addition, the gaps in knowledge uncovered in this review are important areas for future research.

Temporomandibular Disorders and Bruxism among Sex Workers-A Cross Sectional Study

Sex workers are a highly underprivileged population which is present all around the world. Sex work is associated with negative social stigma which affects all aspects of the sex workers' lives including healthcare, service providers and police. The stigma may result in increased stress, mental health problems, feelings of isolation and social exclusion. In the present study, 36 sex workers (SW) and 304 subjects from the general population in Israel (GP) were evaluated for the presence of bruxism and Temporomandibular disorders (TMD), with the use of Diagnostic Criteria for Temporomandibular Disorders (DC/TMD- Axis I). When compared to the general population, sex workers presented larger maximal assisted mouth opening and higher prevalence of the following TMD diagnoses: Disc displacement with reduction, Myalgia, Myofascial pain with referral, Arthralgia (left and right) and Headache attributed to TMD. The odds of sex workers suffering from one of these diagnoses were twice to five times higher than those of the general population. The study shows that health problems of sex workers go beyond venereal diseases, HIV and mental disorders which are commonly studied. Oral health, TMD and oral parafunctions are some of the additional health issues that should be addressed and explored in this population.

Clinical factors affecting depression in patients with painful temporomandibular disorders during the COVID-19 pandemic

Temporomandibular disorders (TMD) are a multifactorial condition associated with both physical and psychological factors. Stress has been known to trigger or worsens TMD. We aimed to investigate whether the novel coronavirus disease-2019 (COVID-19) pandemic aggravates depression in patients with painful TMD, and the factors that affect their level of depression. We included 112 patients with painful TMD (74 females, 38 males; mean age: 35.90 ± 17.60 years; myalgia [n = 38], arthralgia [n = 43], mixed joint-muscle TMD pain [n = 31]). TMD was diagnosed based on the Diagnostic Criteria for TMD Axis I. Physical pain intensity was recorded using the visual analog scale (VAS); psycho-emotional status (depression: Beck Depression Inventory [BDI], anxiety: Beck Anxiety Inventory [BAI], and generalized stress related to COVID19: Global Assessment of Recent Stress [GARS]) was investigated twice (before [BC] and after COVID-19 [AC]). Additionally, factors affecting BDI-AC were investigated. BDI (p < 0.001), BAI (p < 0.001), GARS (p < 0.001), and VAS (p < 0.01) scores were significantly increased at AC than BC. The depression, anxiety, and stress levels were significantly positively correlated, and the AC and BC values of each factor showed a high correlation. In the mixed TMD group, BDI-AC was positively correlated with VAS-AC (p < 0.001). In the multiple regression analysis, clenching habit was the strongest predictor of an increase in the BDI scores from moderate to severe, followed by psychological distress, muscle stiffness, female sex, BAI-AC, and TMJ sounds. COVID-19 has negatively affected the psycho-emotional state of patients with painful TMD, and several clinical factors, including female sex and clenching habits, have influenced depression.

Neural correlates of co-occurring pain and depression: an activation-likelihood estimation (ALE) meta-analysis and systematic review

The relationship between pain and depression is thought to be bidirectional and the underlying neurobiology 'shared' between the two conditions. However, these claims are often based on qualitative comparisons of brain regions implicated in pain or depression, while focused quantitative studies of the neurobiology of pain-depression comorbidity are lacking. Particularly, the direction of comorbidity, i.e., pain with depression vs. depression with pain, is rarely addressed. In this systematic review (PROSPERO registration CRD42020219876), we aimed to delineate brain correlates associated with primary pain with concomitant depression, primary depression with concurrent pain, and equal pain and depression comorbidity, using activation likelihood estimation (ALE) meta-analysis. Neuroimaging studies published in English until the 28th of September 2021 were evaluated using PRISMA guidelines. A total of 70 studies were included, of which 26 reported stereotactic coordinates and were analysed with ALE. All studies were assessed for quality by two authors, using the National Institute of Health Quality Assessment Tool. Our results revealed paucity of studies that directly investigated the neurobiology of pain-depression comorbidity. The ALE analysis indicated that pain with concomitant depression was associated with the right amygdala, while depression with concomitant pain was related primarily to the left dorsolateral prefrontal cortex (DLPFC). We provide evidence that pain and depression have a cumulative negative effect on a specific set of brain regions, distinct for primary diagnosis of depression vs. pain.

Prevalence of Central Sensitization in Patients With Hidradenitis Suppurativa

Importance

Chronic pain is one of the most prominent symptoms of hidradenitis suppurativa (HS) and an independent domain in the core outcome set for HS. Previously, the chronic, recurrent, inflammatory nature of HS was hypothesized to induce central sensitization (CS; alteration and amplification of pain perception). However, evidence for this hypothesis is currently lacking.

Objective

To determine the prevalence of CS in patients with HS compared with sex- and age-matched controls.

Design, Setting, and Participants

This was a cross-sectional, survey-based, case-control study conducted from February to November 2020 that included all consecutive adult patients with HS attending the outpatient clinic of the Department of Dermatology of the Erasmus University Medical Center Rotterdam, in Rotterdam, the Netherlands. Age- and sex-matched controls without chronic inflammatory dermatologic diseases were recruited from the same department.

Main Outcomes and Measures

The main outcome was the Central Sensitization Inventory (CSI) score (ranging from 0-100) as a screening tool for presence of CS. Based on current literature, a score of 40 or higher was deemed to indicate the presence of CS.

Results

Overall, 100 patients with HS (median [IQR] age, 34.5 [27.3-47.0] years; 71 [71%] female) and 100 controls (median [IQR] age, 33.5 [27.0-48.8] years; 71 [71%] female) were included, of which 36% and 12%, respectively, had a CSI score of 40 or higher (P < .001). Multivariate logistic regression showed that patients with HS had 4.46 (95% CI, 1.89-10.52; P = .001) times the odds of having a positive CSI compared with controls. In addition, CS was significantly associated with previously diagnosed depression (odds ratio, 6.16; 95% CI, 2.81-13.54; P < .001). No association between CSI score and disease severity was found.

Conclusions and Relevance

In this cross-sectional, case-control study, patients with HS had more than 4 times the odds of having CS, indicated by a positive CSI, compared with age- and sex-matched controls. This new insight in the presence of CS in patients with HS raises the question of whether we are adequately measuring and treating HS-associated pain. Active screening for CS and depressive symptoms in patients with a discrepant pain experience is recommended.

How environmental enrichment balances out neuroinflammation in chronic pain and comorbid depression and anxiety disorders

Depression and anxiety commonly occur in chronic pain states and the coexistence of these diseases worsens outcomes for both disorders and may reduce treatment adherence and response. Despite the advances in the knowledge of chronic pain mechanisms, pharmacological treatment is still unsatisfactory. Research based on exposure to environmental enrichment is currently under investigation and seems to offer a promising low-cost strategy with no side effects. In this review, we discuss the role of inflammation as a major biological substrate and aetiological factor of chronic pain and depression/anxiety and report a collection of preclinical evidence of the effects and mechanisms of environmental enrichment. As microglia participates in the development of both conditions, we also discuss microglia as a potential target underlying the beneficial actions of environmental enrichment in chronic pain and comorbid depression/anxiety. We also discuss how alternative interventions under clinical guidelines, such as environmental enrichment, may improve treatment compliance and patient outcomes.

Biological Evaluation of Aegle marmelos Fruit Extract and Isolated Aegeline in Alleviating PainDepression Dyad: In Silico Analysis of Aegeline on MAO-A and iNOS

Pain and depression have been assessed to co-occur in up to 80% of patients, and this comorbidity is more debilitating and pricier for the patients as compared to either of these disorders alone. Aegle marmelos is a well-known medicinal plant with a broad spectrum of pharmacological activities. Aegeline is a relatively unexplored molecule present in Aegle marmelos. Therefore, the current investigation aims to explore the potential of Aegle marmelos fruit extract (AMFE) and isolated aegeline against the reserpine-induced pain-depression dyad. In the current investigation, aegeline was isolated from AMFE, followed by spectroscopic characterization, i.e., using NMR and mass analyses. AMFE (200 mg kg^-1 p.o) and aegeline (10 mg kg^-1 p.o.) were administered to reserpinized (0.5 mg kg^-1 s.c.) mice, and clorgyline (3 mg kg^-1 i.p.) was taken as the standard drug. AMFE and aegeline significantly alleviated the reserpine-induced reduction in a pain threshold and an increase in immobility as observed in behavioral tests of pain and depression, respectively. In silico molecular docking studies of aegeline showed a good binding interaction at the active sites of MAO-A and iNOS. The in vivo analysis showed that AMFE and aegeline treatment significantly decreased the monoamine oxidase-A (MAO-A) activity, serum interleukin-6 (IL-6) level, and lipid peroxidation, along with an increase in the reduced glutathione level in comparison to the reserpine-treated group. Immunofluorescence studies also showed that AMFE and aegeline abrogated the reserpine-induced increase in iNOS expression. Conclusively, the results delineate that AMFE and aegeline might exert a protective effect via downregulating the MAO-A hyperactivity, IL-6 level, oxidative and nitrosative stress.

Skimmetin/osthole mitigates pain-depression dyad via inhibiting inflammatory and oxidative stress-mediated neurotransmitter dysregulation

Pain and depression are often co-existing pathological states that promote mutual severity resulting in limited efficacy of current treatment strategies. Thus, there is a need to develop an efficacious alternate treatment regimen for pain-depression dyad. Skimmetin and osthole are molecules of natural origin that have been explored for an anti-hyperglycemic, anti-bacterial, anti-fungal, and anti-diabetic activities in preclinical studies. in animal models. The current study has been designed to explore the beneficial effect of skimmetin/osthole in reserpine-induced pain-depression dyad in mice. Female Swiss albino mice (n = 6) were challenged with reserpine (0.5 mg/kg s.c.) for the first 3 days to induce a pain-depression dyad-like state. Skimmetin (10 mg/kg i.p.) and osthole (10 mg/kg i.p.) were administered for 5 days consecutively, starting from the first day of study. Reserpine treatment significantly reduced the pain threshold in the pressure application measurement (PAM) and electronic von frey (eVF) test. In forced swim test (FST) and Morris water maze (MWM) test mice displayed an increased immobility time and latency to reach platform respectively. Biochemical results showed an increased level of TNF-α, IL-1β, TBARS, glutamate, and reduced level of GSH, norepinephrine, and serotonin in the reserpine treated group. Reserpine treatment also increased brain MAO-A activity. Skimmetin/osthole treatment was found to attenuate the behavioral and biochemical alterations induced by reserpine. The results of the current investigation delineated that skimmetin/osthole may exert anti-nociceptive, anti-depressant, and improved cognition via inhibiting inflammatory and oxidative stress-mediated neurotransmitter dysregulation.

NIRS measures in pain and analgesia: Fundamentals, features, and function

Current pain assessment techniques based only on clinical evaluation and self-reports are not objective and may lead to inadequate treatment. Having a functional biomarker will add to the clinical fidelity, diagnosis, and perhaps improve treatment efficacy in patients. While many approaches have been deployed in pain biomarker discovery, functional near-infrared spectroscopy (fNIRS) is a technology that allows for non-invasive measurement of cortical hemodynamics. The utility of fNIRS is especially attractive given its ability to detect specific changes in the somatosensory and high-order cortices as well as its ability to measure (1) brain function similar to functional magnetic resonance imaging, (2) graded responses to noxious and innocuous stimuli, (3) analgesia, and (4) nociception under anesthesia. In this review, we evaluate the utility of fNIRS in nociception/pain with particular focus on its sensitivity and specificity, methodological advantages and limitations, and the current and potential applications in various pain conditions. Everything considered, fNIRS technology could enhance our ability to evaluate evoked and persistent pain across different age groups and clinical populations.

Postmarketing safety surveillance data reveals antidepressant effects of botulinum toxin across various indications and injection sites

The World Health Organization estimates the number of people suffering from depression to be over 264 million. Current monoamine transmission modulating therapeutics, even with proper adherence and acceptable tolerability, are not effective for nearly one third of the patients, leading clinicians to explore other therapeutic options such as electroconvulsive therapy, transcranial magnetic stimulation, ketamine infusions, and, more recently, glabellar botulinum toxin, BoNT, injections. The scale and mechanism of antidepressant action of BoNT is unclear and maybe hypothetically attributed to the disruption of proprioceptive facial feedback reinforcing negative emotions. Here we verify the antidepressant effect of botulinum toxin by analysis of over 40 thousand BoNT treatment reports out of thirteen million postmarketing safety reports in the FDA Adverse Event Reporting System, FAERS. The results of the analysis indicate that patients who received BoNT injections to treat hyperhidrosis, facial wrinkles, migraine prophylaxis, spasticity, and spasms, had a significantly lower number of depression reports when compared to patients undergoing different treatments for the same conditions. These findings suggest that the antidepressant effect of BoNT is significant, and, surprisingly, is observed for a broad range of injection sites.

A Systematic Review of Efficacy, Safety, and Tolerability of Duloxetine

Duloxetine is a serotonin-norepinephrine reuptake inhibitor approved for the treatment of patients affected by major depressive disorder (MDD), generalized anxiety disorder (GAD), neuropathic pain (NP), fibromyalgia (FMS), and stress incontinence urinary (SUI). These conditions share parallel pathophysiological pathways, and duloxetine treatment might be an effective and safe alternative. Thus, a systematic review was conducted following the 2009 Preferred Reporting Items (PRISMA) recommendations and Joanna Briggs Institute Critical (JBI) Appraisals guidelines. Eighty-five studies focused on efficacy, safety, and tolerability of duloxetine were included in our systematic review. Studies were subdivided by clinical condition and evaluated individually. Thus, 32 studies of MDD, 11 studies of GAD, 19 studies of NP, 9 studies of FMS, and 14 studies of SUI demonstrated that the measured outcomes indicate the suitability of duloxetine in the treatment of these clinical conditions. This systematic review confirms that the dual mechanism of duloxetine benefits the treatment of comorbid clinical conditions, and supports the efficacy, safety, and tolerability of duloxetine in short- and long-term treatments.

Depression Increases the Rates of Neurological Complications and Failed Back Surgery Syndrome in Patients Undergoing Lumbar Spine Surgery

STUDY DESIGN

This was a retrospective database study.

OBJECTIVE

The aim of this study was to use a large sample to accurately determine risk factors and rates of neurological complications in patients undergoing commonly performed lumbar spine surgeries.

SUMMARY OF BACKGROUND DATA

Damage to neurological structures and failed back surgery syndrome (FBSS) are among the most feared complications of lumbar spine surgery. Despite the large impact on quality of life these complications have, reported rates of neurological complications vary immensely, ranging from 0.46% to 24%.

MATERIALS AND METHODS

Data were obtained for patients undergoing initial posterior lumbar interbody fusion, transforaminal lumbar interbody fusion, anterior lumbar interbody fusion, posterolateral fusion, discectomy, and laminectomy procedures from January 2007 to June 2015 covered by the nationwide insurance carrier Humana. Patient records were analyzed to determine rates of dural tear, damage to nervous tissue, cauda equina syndrome, neurogenic bowel/bladder, and FBSS following each procedure. Rates were determined for patients undergoing single/multilevel procedures, by age, and for patients with a previous diagnosis of depression to determine the influence these factors had on the risk of neurologic complications.

RESULTS

Analysis of 70,581 patient records revealed a dural tear rate of 2.87%, damage to the nervous tissue of 1.47%, cauda equina syndrome of 0.75%, neurogenic bowel or bladder of 0.45%, and FBSS of 15.05% following lumbar spine surgery. The incidence of complications was highest for patients undergoing multilevel procedures and posterior fusion. Depression was a significant risk factor for FBSS (risk ratio, 1.74; P<0.0001), damage to nervous tissue (1.41; P<0.0001), and dural tear (1.15; P<0.0001), but had no impact on risk of cauda equina syndrome or neurogenic bowel or bladder. Increased age was associated with higher rates of dural tear and damage to nervous tissue.

CONCLUSIONS

Patients with a history of depression are at significantly increased risk for neurologic complications following lumbar spine surgery and should be managed accordingly.

Chronic pain, depression and cognitive impairment: a close relationship

Over a half of chronic pain (CP) patients present with cognitive complaints, which increase their disability and impact quality of life. The paper reviews objective impairments in memory, attention, processing speed and executive function demonstrated in the CP population. The paper also reviews common pathology underlying cognitive impairment and CP: neuroplasticity in the shared brain areas, neurotransmitter and other molecular mechanisms. Common mechanisms in CP and depression precipitating cognitive impairment are also discussed. The paper also compares the potential of different antidepressants to improve cognitive functions in depression and CP.

Theoretical Modeling of Cognitive Dysfunction in Schizophrenia by Means of Errors and Corresponding Brain Networks

The current evidence of cognitive disturbances and brain alterations in schizophrenia does not provide the plausible explanation of the underlying mechanisms. Neuropsychological studies outlined the cognitive profile of patients with schizophrenia, that embodied the substantial disturbances in perceptual and motor processes, spatial functions, verbal and non-verbal memory, processing speed and executive functioning. Standardized scoring in the majority of the neurocognitive tests renders the index scores or the achievement indicating the severity of the cognitive impairment rather than the actual performance by means of errors. At the same time, the quantitative evaluation may lead to the situation when two patients with the same index score of the particular cognitive test, demonstrate qualitatively different performances. This may support the view why test paradigms that habitually incorporate different cognitive variables associate weakly, reflecting an ambiguity in the interpretation of noted cognitive constructs. With minor exceptions, cognitive functions are not attributed to the localized activity but eventuate from the coordinated activity in the generally dispersed brain networks. Functional neuroimaging has progressively explored the connectivity in the brain networks in the absence of the specific task and during the task processing. The spatio-temporal fluctuations of the activity of the brain areas detected in the resting state and being highly reproducible in numerous studies, resemble the activation and communication patterns during the task performance. Relatedly, the activation in the specific brain regions oftentimes is attributed to a number of cognitive processes. Given the complex organization of the cognitive functions, it becomes crucial to designate the roles of the brain networks in relation to the specific cognitive functions. One possible approach is to identify the commonalities of the deficits across the number of cognitive tests or, common errors in the various tests and identify their common "denominators" in the brain networks. The qualitative characterization of cognitive performance might be beneficial in addressing diffuse cognitive alterations presumably caused by the dysconnectivity of the distributed brain networks. Therefore, in the review, we use this approach in the description of standardized tests in the scope of potential errors in patients with schizophrenia with a subsequent reference to the brain networks.

Enriched Environment and Effects on Neuropathic Pain: Experimental Findings and Mechanisms

Neuropathic pain inflicts tremendous biopsychosocial suffering for patients worldwide. However, safe and effective treatment of neuropathic pain is a prominent unmet clinical need. Environmental enrichment (EE) is an emerging cost-effective nonpharmacological approach to alleviate neuropathic pain and complement rehabilitation care. We present here a review of preclinical studies in ascertaining the efficacy of EE for neuropathic pain. Their proposed mechanisms, including the suppression of ascending nociceptive signaling to the brain, enhancement of the descending inhibitory system, and neuroprotection of the peripheral and central nervous systems, may collectively reduce pain perception and improve somatic and emotional functioning in neuropathic pain. The current evidence offers critical insights for future preclinical research and the translational application of EE in clinical pain management.

Epidemiology of mental health conditions in incoming division I collegiate athletes

OBJECTIVES

The purpose of this study is to examine the epidemiology of mental health conditions in incoming American Division I collegiate athletes.

METHODS

Pre-participation physical questionnaires from 1118 incoming student athletes at a Division I Institution were collected retrospectively from 2011-2017. Data collected included lifetime history of any mental health condition, musculoskeletal injuries, concussions, and post-concussion depression. History of any mental health condition was evaluated by gender and sport played. It was also evaluated in comparison to musculoskeletal injuries and concussions.

RESULTS

The lifetime prevalence of any mental health condition was 14.0% for all athletes, 14.2% for male athletes, and 13.6% for female athletes. Individual sports reported a greater prevalence (17.2%) than did team sports (11.8%) (p = 0.010). The prevalence was also higher in contact sports (16.4%) than in non-contact sports (12.5%), although this difference was not statistically significant (p = 0.072). There was a significant association between mental health condition and all four major groups of injuries examined: upper extremity (p = 0.043), lower extremity (p = 0.007), axial skeletal (p < 0.001), and concussions (p = 0.039). Post-concussion depression occurred in 2.0% of all athletes reporting a concussion.

CONCLUSION

The lifetime prevalence of mental health conditions in this population (14.0%) is far less than estimates in the general population. This observation may be due to a combination of factors including exercise/athletic participation mitigating depressive symptoms, competitive selection, and underreporting. History of a mental health condition may be associated with injury, although causation cannot be determined.

Changes in Pain Perception following Psychotherapy: The Mediating Role of Psychological Components

Chronic pain is frequently associated with significant psychological issues, such as depression or anxiety. Psychological treatments, such as psychotherapy, can often alleviate both psychological and pain symptoms. However, there is limited research about the association between psychological symptoms and perceived pain in the context of psychotherapeutic interventions. We conducted a retrospective study that analyzed, in a hospital context, how changes in psychological functioning and well-being were associated with pain reduction. Thirty-seven records of patients with chronic pain attending psychotherapy in a public hospital were included. All patients were assessed before psychotherapy, as well as after 6 and 10 months, with self-reported questionnaires about pain, anxiety, depression, and psychological functioning. Results indicate that reductions in anxiety, depression, psychological problems, risk factors, and well-being are strongly related with a reduction in pain, further confirming the hypothesis that psychological morbidity is associated with pain severity.

The stress concept in gastroenterology: from Selye to today

More than eighty years after Hans Selye (1907-1982) first developed a concept describing how different types of environmental stressors affect physiological functions and promote disease development (called the "general adaptation syndrome") in 1936, we herein review advances in theoretical, mechanistic, and clinical knowledge in stress research, especially in the area of gastroenterology, and summarize progress and future perspectives arising from an interdisciplinary psychoneurobiological framework in which genetics, epigenetics, and other advanced ( omics) technologies in the last decade continue to refine knowledge about how stress affects the brain-gut axis in health and gastrointestinal disease. We demonstrate that neurobiological stress research continues to be a driving force for scientific progress in gastroenterology and related clinical areas, inspiring translational research from animal models to clinical applications, while highlighting some areas that remain incompletely understood, such as the roles of sex/gender and gut microbiota in health and disease. Future directions of research should include not only the genetics of the stress response and resilience but also epigenetic contributions.

Affective and cognitive behavior in the alpha-galactosidase A deficient mouse model of Fabry disease

Fabry disease is an X-linked inherited lysosomal storage disorder with intracellular accumulation of globotriaosylceramide (Gb3) due to α-galactosidase A (α-Gal A) deficiency. Fabry patients frequently report of anxiety, depression, and impaired cognitive function. We characterized affective and cognitive phenotype of male mice with α-Gal A deficiency (Fabry KO) and compared results with those of age-matched male wildtype (WT) littermates. Young (3 months) and old (≥ 18 months) mice were tested in the naïve state and after i.pl. injection of complete Freund`s adjuvant (CFA) as an inflammatory pain model. We used the elevated plus maze (EPM), the light-dark box (LDB) and the open field test (OF) to investigate anxiety-like behavior. The forced swim test (FST) and Morris water maze (MWM) were applied to assess depressive-like and learning behavior. The EPM test revealed no intergroup difference for anxiety-like behavior in naïve young and old Fabry KO mice compared to WT littermates, except for longer time spent in open arms of the EPM for young WT mice compared to young Fabry KO mice (p<0.05). After CFA injection, young Fabry KO mice showed increased anxiety-like behavior compared to young WT littermates (p<0.05) and naïve young Fabry KO mice (p<0.05) in the EPM as reflected by shorter time spent in EPM open arms. There were no relevant differences in the LDB and the OF test, except for longer time spent in the center zone of the OF by young WT mice compared to young Fabry KO mice (p<0.05). Complementary to this, depression-like and learning behavior were not different between genotypes and age-groups, except for the expectedly lower memory performance in older age-groups compared to young mice. Our results indicate that genetic influences on affective and cognitive symptoms in FD may be of subordinate relevance, drawing attention to potential influences of environmental and epigenetic factors.

A Brief Review of the Pharmacology of Amitriptyline and Clinical Outcomes in Treating Fibromyalgia

Fibromyalgia is a complex chronic condition characterized by pain, physical fatigue, sleep disorder and cognitive impairment. Evidence-based guidelines recommend antidepressants as treatments of fibromyalgia where tricyclics are often considered to have the greatest efficacy, with amitriptyline often being a first-line treatment. Amitriptyline evokes a preferential reduction in pain and fatigue of fibromyalgia, and in the Fibromyalgia Impact Questionnaire (FIQ) score, which is a quality of life assessment. The multimodal profile of the mechanisms of action of amitriptyline include monoamine reuptake inhibition, receptor modulation and ion channel modulation. Several of the actions of amitriptyline on multiple nociceptive and sensory processes at central and peripheral locations have the potential to act cumulatively to suppress the characteristic symptoms of fibromyalgia. Greater understanding of the role of these mechanisms of action of amitriptyline could provide further clues to the pathophysiology of fibromyalgia and to a preferable pharmacological profile for future drug development.

Modulation of NMDA Receptor Activity in Fibromyalgia

Activation of the N-methyl-d-aspartate receptor (NMDAR) results in increased sensitivity of spinal cord and brain pathways that process sensory information, particularly those which relate to pain. The NMDAR shows increased activity in fibromyalgia and hence modulation of the NMDAR is a target for therapeutic intervention. A literature review of interventions impacting on the NMDAR shows a number of drugs to be active on the NMDAR mechanism in fibromyalgia patients, with variable clinical effects. Low-dose intravenous ketamine and oral memantine both show clinically useful benefit in fibromyalgia. However, consideration of side-effects, logistics and cost need to be factored into management decisions regarding use of these drugs in this clinical setting. Overall benefits with current NMDAR antagonists appear modest and there is a need for better strategy trials to clarify optimal dose schedules and to delineate potential longer–term adverse events. Further investigation of the role of the NMDAR in fibromyalgia and the effect of other molecules that modulate this receptor appear important to enhance treatment targets in fibromyalgia.

Causal Mediation in the Development of Painful Temporomandibular Disorder

We explored causal mediation of sleep quality and perceived stress in development of painful temporomandibular disorder (TMD). Sleep quality and perceived stress were assessed at baseline and quarterly intervals thereafter in 2,737 initially TMD-free adults in the Orofacial Pain Prospective Evaluation and Risk Assessment study (OPPERA) prospective cohort study. During follow-up, incident TMD cases were classified using research diagnostic criteria. Mediation analysis was conducted using a weighted Cox proportional hazards regression model that estimated hazard ratios (HRs) and 95% confidence limits (CL) of first-onset TMD. Models determined whether: 1) poor sleep quality during follow-up mediated the effect of baseline perceived stress on first-onset TMD, and 2) perceived stress during follow-up mediated the effect of baseline poor sleep quality on first-onset TMD. In both analyses, the total effect was decomposed into natural direct and indirect effects. Poor baseline sleep quality led to heightened perceived stress that then contributed to TMD development. When the total effect of poor sleep quality (HR = 2.10, CL = 1.76, 2.50) was decomposed, 34% of its effect was mediated by perceived stress (indirect effect HR = 1.29, CL = 1.06, 1.58). The effect of perceived stress on first-onset TMD was not mediated by sleep quality. Improving sleep may avert escalation of stress, limiting effects of both factors on TMD development.

PERSPECTIVE

Causal mediation analysis highlights mechanisms by which poor sleep quality promotes development of TMD. First, poor sleep quality exerts a direct effect on pain. Second, it triggers a heightened perception of stress, which acts as an intermediate factor in the causal pathway between poor sleep quality and first-onset TMD pain.

Antinociceptive and Anti-Inflammatory Effects of Ketamine and the Relationship to Its Antidepressant Action and GSK3 Inhibition

Ketamine (KET), a NMDA antagonist, exerts an antidepressant effect at subanaesthetic doses and possesses analgesic and anti-inflammatory activities. We evaluated the involvement of KET antinociceptive and anti-inflammatory effects with its antidepressant action. Male Swiss mice were subjected to formalin, carrageenan-induced paw oedema and forced swimming tests, for assessing antinociceptive, anti-inflammatory and antidepressant effects. The treatment groups were as follows: control, KET (2, 5 and 10 mg/kg), lithium (LI: 5 mg/kg) and KET2 + LI5 combination. Immunohistochemistry analyses (TNF-α, iNOS, COX-2 and GSK3) in oedematous paws were performed. KET5 and KET10 reduced licking times in neurogenic (22 and 38%) and inflammatory (67 and 78%) phases of the formalin test, respectively, as related to controls. While LI5 inhibited the second phase by 24%, the licking time was inhibited by 26 and 59% in the KET2 + LI5 group (first and second phases). Furthermore, oedema volumes were reduced by 37 and 45% in the KET5 and KET10 groups, respectively. Oedema reductions were 29% in the LI5 group and 48% in the KET2 + LI5 group. In the forced swimming test, there were 23, 38 and 53% decreases in the immobility time in KET2, KET5 and KET10 groups, respectively. While LI5 caused no significant effect, decreases of 52% were observed with KET2 + LI5. KET also decreased TNF-α, iNOS, COX-2 and GSK3 immunostainings in oedematous paws, effects intensified with KET2 + LI5. We showed that KET presents antinociceptive and anti-inflammatory effects associated with its antidepressant response. Furthermore, our results indicate the close involvement of GSK3 inhibition and blockade of inflammatory responses, in the antidepressant drug effect.

Effect of drugs modulating serotonergic system on the analgesic action of paracetamol in mice

Objective:

The underlying mechanisms for the analgesic action of paracetamol (PCT) are still under considerable debate. It has been recently proposed that PCT may act by modulating the Serotonin system. This study was conducted to verify the influence of Serotonin modulating drugs (buspirone, ondansetron, and fluoxetine) on the analgesic effect of PCT.

Materials and Methods:

Thirty adult albino mice were assigned to five groups: Normal saline, PCT, fluoxetine selective serotonin reuptake inhibitor (SSRI) + PCT, buspirone (5-HT_1A Agonist) + PCT, and ondansetron (5HT₃ antagonist) + PCT. Hot-plate and formalin test were used to determine pain threshold, tests being conducted 60 min after the last treatment. Statistical analysis was done using analysis of variance followed by Dunnet's test.

Results:

Coadministration of buspirone with PCT attenuated the antinociceptive activity of PCT (P < 0.001), whereas fluoxetine + PCT increased pain threshold in the hot-plate and formalin test (P = 0.0046). Analgesic effect of PCT was not affected by ondansetron in formalin models. It attenuated analgesic action of PCT in hot-plate test (P = 0.0137).

Conclusion:

The results suggest that 5-HT₁ receptors could also be responsible for the analgesic effect of PCT. Also, higher analgesia is produced by co-administration of SSRI (fluoxetine) + PCT.

Does preoperative psychological status of patients affect postoperative pain? A prospective study from the Caribbean

OBJECTIVES

Patients with high anxiety states in the preoperative period often have more intense postoperative pain, despite adequate pain control during the intraoperative period. This study aimed to determine the relationship between the preoperative psychological status and the pain experienced postoperatively in a sample of Caribbean patients.

DESIGN AND METHODS

A prospective study was conducted in elective surgical adult patients at a teaching hospital in the Caribbean. Patients' preoperative psychological status was assessed using Hospital Anxiety and Depression Scale (HADS), and a preoperative 'expected' pain score was recorded. Postoperatively, 'observed' pain scores at 4 and 24 hours and the maximum pain score during 24 hours were recorded. Demographic data and clinical details including data regarding postoperative analgesia were collected. Expected and observed pain scores were compared between patients with and without anxiety and depression.

RESULTS

A total of 304 patients were enrolled. The overall prevalence of anxiety and depression was 43% and 27%, respectively, based on the HADS scores. There were significant associations between the postoperative pain scores and factors such as preoperative anxiety and depression (HADS) scores, preoperative expected pain scores, patient educational level, presence of preoperative pain and surgical duration. Age, gender, ethnicity and type of anaesthesia did not impact postoperative pain scores.

CONCLUSION

The presence of preoperative anxiety and depression as indicated by HADS score may significantly influence postoperative pain. Other factors such as educational level, presence of preoperative pain and surgical duration may also impact postoperative pain. Some of these factors may be modifiable and must be addressed in the preoperative period.

Pain, depression and sleep disorders in patients with diabetic and nondiabetic carpal tunnel syndrome: a vicious cycle

ABSTRACT Carpal tunnel syndrome (CTS) is a condition involving nerve entrapment that often leads to chronic neuropathic pain. We aimed to evaluate sleep quality and related parameters in diabetic and non-diabetic CTS patients. Method This study included a total of 366 patients with chronic CTS. These patients’ sleep quality was evaluated using the Pittsburgh Sleep Quality Index (PSQI) and depression using the Beck Depression Inventory (BDI). The severity of neuropathic pain was evaluated using the Douleur Neuropathique-4 (DN4) questionnaire and a visual analogue scale (VAS). Results In the non-diabetic patient group, the total PSQI score was found to affect BDI and VAS, while in the diabetic patient group, the duration of symptoms affected VAS, BDI and fasting glucose levels. Conclusion For diabetic patients, hyperglycemia depression and chronification of neuropathic pain may lead to deterioration of sleep quality. Therefore, consideration of these parameters in the treatment may break a vicious cycle.

Chronic pain causes a persistent anxiety state leading to increased ethanol intake in CD1 mice

Mood disorders and chronic pain are closely linked, but limited progress has been made in understanding the role of chronic and neuropathic pain in the aetiopathogenesis of depression. To explore the pathological mechanisms that mediate the association between pain and depressive-like behaviours, we studied the time-dependent effect of neuropathic pain on the development of anxiety-like and despair behaviours in CD1 mice. We analysed behavioural data, neuroinflammation reactions and changes in neurotransmitter (glutamate and serotonin) levels in the mouse prefrontal cortex. Sciatic-operated mice displayed long-lasting anxiety-like and despair behaviours, starting 5 and 20 days after partial sciatic nerve ligation, respectively. Glutamatergic neurotransmission and IL-1β cytokine expression were enhanced in the prefrontal cortex of mice with neuropathic pain. We found no change in serotonin metabolism, cytokine IL-6 or brain-derived neurotrophic factor levels. While sciatic-operated mice exposed to intermittent ethanol intake (20% v/v) using the drinking in the dark procedure consumed higher amounts of ethanol than sham-operated mice, thermal allodynia and despair behaviour were not attenuated by ethanol consumption. Our findings reveal an association between glutamatergic neurotransmission and pain-induced mood disorders, and indicate that moderate ethanol consumption does not relieve nociceptive and depressive behaviours associated with chronic pain in mice.

Could Stress Contribute to Pain-Related Fear in Chronic Pain?

Learning to predict pain based on internal or external cues constitutes a fundamental and highly adaptive process aimed at self-protection. Pain-related fear is an essential component of this response, which is formed by associative and instrumental learning processes. In chronic pain, pain-related fear may become maladaptive, drive avoidance behaviors and contribute to symptom chronicity. Pavlovian fear conditioning has proven fruitful to elucidate associative learning and extinction involving aversive stimuli, including pain, but studies in chronic pain remain scarce. Stress demonstrably exerts differential effects on emotional learning and memory processes, but this has not been transferred to pain-related fear. Within this perspective, we propose that stress could contribute to impaired pain-related associative learning and extinction processes and call for interdisciplinary research. Specifically, we suggest to test the hypotheses that: (1) extinction-related phenomena inducing a re-activation of maladaptive pain-related fear (e.g., reinstatement, renewal) likely occur in everyday life of chronic pain patients and may alter pain processing, impair perceptual discrimination and favor overgeneralization; (2) acute stress prior to or during acquisition of pain-related fear may facilitate the formation and/or consolidation of pain-related fear memories; (3) stress during or after extinction may impair extinction efficacy resulting in greater reinstatement or context-dependent renewal of pain-related fear; and (4) these effects could be amplified by chronic stress due to early adversity and/or psychiatric comorbidity such depression or anxiety in patients with chronic pain.

Identification of Spinal Cord MicroRNA and Gene Signatures in a Model of Chronic Stress-Induced Visceral Hyperalgesia in Rat

Introduction

Animal studies have shown that stress could induce epigenetic and transcriptomic alterations essential in determining the balance between adaptive or maladaptive responses to stress. We tested the hypothesis that chronic stress in rats deregulates coding and non-coding gene expression in the spinal cord, which may underline neuroinflammation and nociceptive changes previously observed in this model.

Methods

Male Wistar rats were exposed to daily stress or handled, for 10 days. At day 11, lumbar spinal segments were collected and processed for mRNA/miRNA isolation followed by expression profiling using Agilent SurePrint Rat Exon and Rat miRNA Microarray platforms. Differentially expressed gene lists were generated using the dChip program. Microarrays were analyzed using the Ingenuity Pathways Analysis (IPA) tool from Ingenuity Systems. Multiple methods were used for the analysis of miRNA-mRNA functional modules. Quantitative real time RT-PCR for Interleukin 6 signal transducer (gp130), the Signal Transducer And Activator Of Transcription 3 (STAT3), glial fibrillary acidic protein and mir-17-5p were performed to confirm levels of expression.

Results

Gene network analysis revealed that stress deregulated different inflammatory (IL-6, JAK/STAT, TNF) and metabolic (PI3K/AKT) signaling pathways. MicroRNA array analysis revealed a signature of 39 deregulated microRNAs in stressed rats. MicroRNA-gene network analysis showed that microRNAs are regulators of two gene networks relevant to inflammatory processes. Specifically, our analysis of miRNA-mRNA functional modules identified miR-17-5p as an important regulator in our model. We verified miR-17-5p increased expression in stress using qPCR and in situ hybridization. In addition, we observed changes in the expression of gp130 and STAT3 (involved in intracellular signaling cascades in response to gp130 activation), both predicted targets for miR-17-5p. A modulatory role of spinal mir17-5p in the modulation of visceral sensitivity was confirmed in vivo.

Conclusion

Using an integrative high throughput approach, our findings suggest a link between miR-17-5p increased expression and gp130/STAT3 activation providing new insight into the possible mechanisms mediating the effect of chronic stress on neuroinflammation in the spinal cord.

Effect of Repeated Electroacupuncture Intervention on Hippocampal ERK and p38MAPK Signaling in Neuropathic Pain Rats

Results of our past studies showed that hippocampal muscarinic acetylcholine receptor (mAChR)-1 mRNA and differentially expressed proteins participating in MAPK signaling were involved in electroacupuncture (EA) induced cumulative analgesia in neuropathic pain rats, but the underlying intracellular mechanism remains unknown. The present study was designed to observe the effect of EA stimulation (EAS) on hippocampal extracellular signal-regulated kinases (ERK) and p38 MAPK signaling in rats with chronic constrictive injury (CCI) of the sciatic nerve, so as to reveal its related intracellular targets in pain relief. After CCI, the thermal pain thresholds of the affected hind were significantly decreased compared with the control group (P < 0.05). Following one and two weeks' EAS of ST 36-GB34, the pain thresholds were significantly upregulated (P < 0.05), and the effect of EA2W was remarkably superior to that of EA2D and EA1W (P < 0.05). Correspondingly, CCI-induced decreased expression levels of Ras, c-Raf, ERK1 and p-ERK1/2 proteins, and p38 MAPK mRNA and p-p38MAPK protein in the hippocampus tissues were reversed by EA2W (P < 0.05). The above mentioned results indicated that EA2W induced cumulative analgesic effect may be closely associated with its function in removing neuropathic pain induced suppression of intracellular ERK and p38MAPK signaling in the hippocampus.

Acute pain service: past, present and future

SUMMARY 

Post surgical pain is a continuing major medical challenge despite all the advances in understanding acute pain and the development of new modalities of pain management. Since 1985 when the first acute pain service (APS) was started, many organizations initiated APS protocols and guidelines and it became mandatory to have an APS in all major acute care centers. This review focuses on the stages of development of APS and the challenges of postoperative pain management to provide optimal analgesia. Further clinical studies are required to determine best medication regimen for post-operative pain management.

Prescription opioid use among disabled Medicare beneficiaries: intensity, trends, and regional variation

BACKGROUND

Prescription opioid use and overdose deaths are increasing in the United States. Among disabled Medicare beneficiaries under the age of 65, the rise in musculoskeletal conditions as qualifying diagnoses suggests that opioid analgesic use may be common and increasing, raising safety concerns.

METHODS

From a 40% random-sample Medicare denominator, we identified fee-for-service beneficiaries under the age of 65 and created annual enrollment cohorts from 2007 to 2011 (6.4 million person-years). We obtained adjusted, annual opioid use measures: any use, chronic use (≥ 6 prescriptions), intensity of use [daily morphine equivalent dose (MED)], and opioid prescribers per user. Geographic variation was studied across Hospital Referral Regions.

RESULTS

Most measures peaked in 2010. The adjusted proportion with any opioid use was 43.9% in 2007, 44.7% in 2010, and 43.7% in 2011. The proportion with chronic use rose from 21.4% in 2007 to 23.1% in 2011. Among chronic users: mean MED peaked at 81.3 mg in 2010, declining to 77.4 mg in 2011; in 2011, 19.8% received ≥ 100 mg MED; 10.4% received ≥ 200 mg. In 2011, Hospital Referral Region-level measures varied broadly (5th-95th percentile): any use: 33.0%-58.6%, chronic use: 13.9%-36.6%; among chronic users, mean MED: 45 mg-125 mg; mean annual opioid prescribers: 2.4-3.7.

CONCLUSIONS

Among these beneficiaries, opioid use was common. Although intensity stabilized, the population using opioids chronically grew. Variation shows a lack of a standardized approach and reveals regions with mean MED at levels associated with overdose risk. Future work should assess outcomes, chronic use predictors, and policies balancing pain control and safety.