A Review of the Emotional Aspects of Neuropathic Pain: From Comorbidity to Co-Pathogenesis

Clinical Characteristics of Adults Living with a Spinal Cord Injury Across the Continuum of Care: A Population-Based Cross-Sectional Study

Background/Objectives: People living with a spinal cord injury (PwSCI) present numerous complications at a systemic level that negatively impact their physical and mental health as well as their quality of life. The purpose of this study was to describe the clinical profile of PwSCI living in nursing homes (NHs), Complex Continuing Care Systems (CCCs), home care (HC), and inpatient mental health facilities (MHs) in nine Canadian provinces and territories. Methods: We analyzed data collected with the following assessment tools: Resident Assessment Instrument (RAI) Minimum Data Set (RAI-MDS 2.0), RAI-MH, RAI-HC, Cognitive Performance Scale, Activities of Daily Living (ADL) Hierarchy Scale and impairments in instrumental ADLs (IADLs), Pain Scale, Changes in Health, End-Stage Disease, Signs, and Symptoms (CHESS) Scale, Depression Rating Scale, and Deafblind Severity Index (DBSI). We reported counts (n) and percentages (%) and performed Chi-square tests with a Bonferroni correction to determine the statistical significance of the differences in frequencies within and between care settings. Results: We identified 13,136 PwSCI, predominantly males and younger than comparison groups. PwSCI presented fewer comorbidities but reported higher pain than comparison groups. Almost all of the PwSCI in NHs (99.4%) and CCCs (98.9%) needed assistance to perform ADLs. Conclusions: The prevalence of comorbidities and impairments following SCI varies based on the clinical setting. The present clinical profile of PwSCI will inform interventions to improve health of PwSCI across the continuum of care.

The relationships between depression, inflammation and self-reported disease activity in IBD and their impact on healthcare usage

BACKGROUND

Depression is common in people living with Inflammatory Bowel Disease (IBD). Depression rates increase with active disease and are linked to poorer clinical outcomes. Previous studies investigating the relationship between contemporaneous IBD disease activity and depression are often poorly controlled, use small samples and/or rely on self-reported measures of disease activity. Depression and self-reported disease activity (SRDA) are linked to increased healthcare usage, however, objective inflammation is rarely statistically controlled. The primary aim was to understand how self-reported disease activity and inflammation are related to depression. Secondary aims included assessing the relative influence of self-reported disease activity, inflammation and depression on healthcare usage.

METHODS

This was a cross-sectional analysis of baseline data collected as part of a randomised controlled trial (trial registration no: ISRCTN71618461) of a digital treatment for symptom self-management in IBD (n = 599). Bivariate associations of demographic and clinical variables with depression were conducted to identify relevant covariates. Multiple linear regressions assessed (i) the relationships between depression (Patient Health Questionnaire-9 (PHQ-9)), SRDA (IBD-Control) and intestinal inflammation (faecal calprotectin (FCP)) and (ii) whether these variables explained variance in healthcare usage and economic indicators.

RESULTS

Depression was significantly predicted by SRDA (β = -0.82, p < 0.001) but not FCP, with the model explaining 37% of the variance in depression (F(2,596) = 175.1, p < 0.001). FCP was only weakly associated with SRDA (r = -0.16, p < 0.001). Depression was independently associated with visits to primary care (β = 0.19, p < 0.001), IBD secondary care (β = 0.13, p < 0.001), IBD-related A&E attendance (β = 0.10 p < 0.05) and the impact of IBD on productivity (β = 0.24 p < 0.001) in the last 3 months.

CONCLUSIONS

Depression was related to SRDA but not FCP. Depression was also associated with healthcare usage even when SRDA and inflammation were statistically controlled. Routinely assessing and treating depression in IBD alongside managing inflammation may improve symptoms for patients and reduce healthcare costs.

Discovery of Novel Pain Regulators Through Integration of Cross-Species High-Throughput Data

AIMS

Chronic pain is an impeding condition that affects day-to-day life and poses a substantial economic burden, surpassing many other health conditions. This study employs a cross-species integrated approach to uncover novel pain mediators/regulators.

METHODS

We used weighted gene coexpression network analysis to identify pain-enriched gene module. Functional analysis and protein-protein interaction (PPI) network analysis of the module genes were conducted. RNA sequencing compared pain model and control mice. PheWAS was performed to link genes to pain-related GWAS traits. Finally, candidates were prioritized based on node degree, differential expression, GWAS associations, and phenotype correlations.

RESULTS

A gene module significantly over-enriched with the pain reference set was identified (referred to as "pain module"). Analysis revealed 141 pain module genes interacting with 46 pain reference genes in the PPI network, which included 88 differentially expressed genes. PheWAS analysis linked 53 of these genes to pain-related GWAS traits. Expression correlation analysis identified Vdac1, Add2, Syt2, and Syt4 as significantly correlated with pain phenotypes across eight brain regions. NCAM1, VAMP2, SYT2, ADD2, and KCND3 were identified as top pain response/regulator genes.

CONCLUSION

The identified genes and molecular mechanisms may enhance understanding of pain pathways and contribute to better drug target identification.

Clinical measures in chronic neuropathic pain are related to the Kennedy and endocannabinoid pathways

BACKGROUND

Chronic neuropathic pain (CNP) is a debilitating condition, often refractory to currently available drugs. Understanding biochemical alterations in peripheral tissues such as blood will be useful for understanding underlying pathophysiological processes relating to CNP.

METHODS

We collected blood from two independent cohorts of CNP and pain-free controls (CNP n = 129/Controls n = 127) in the UK and Ireland to investigate the relationship between CNP-associated molecular/biochemical alterations and a range of clinical and pain metric parameters. Multiple statistical comparisons were conducted on the data, with selected variables included in one or more of the intended inferential analyses (six models).

RESULTS

Gene expression analysis showed that choline phosphotransferase (CHPT1) was increased (p < .001) in the CNP group compared to controls. The levels of phosphatidylcholine, a metabolite of CHPT1 in the Kennedy Pathway, were significantly (p = .008) decreased in the plasma of patients with CNP. Given the relationship between the Kennedy pathway and endocannabinoids, plasma endocannabinoids and related N-acylethanolamines were quantified in clinical samples by HPLC-Tandem Mass Spectrometry. Plasma levels of the endocannabinoid 2-arachidonoylglycerol were higher in CNP samples compared to controls, and in the statistical models applied, 2-arachidonoylglycerol significantly increased the odds of CNP (p < .001). The expression of genes related to the synthesis and catabolism of endocannabinoids also corroborated the increased plasma 2-arachidonoylglycerol levels in patients with CNP.

CONCLUSIONS

Endocannabinoid levels, expression of genes related to endocannabinoid metabolism, age, sex, depression and anxiety state together were strong predictors of CNP. The observed molecular changes indicate that lipid metabolism is altered in CNP and thus may represent a viable target for novel analgesics or biomarker development.

Preclinical Insights into the Role of Kir4.1 in Chronic Pain and Depression: Mechanisms and Therapeutic Potential

Chronic pain and mental health disorders, such as depression and anxiety, frequently co-occur and share underlying mechanisms involving neuronal excitability and synaptic transmission. The inwardly rectifying potassium channel 4.1 (Kir4.1), predominantly expressed in glial cells, is crucial for maintaining extracellular potassium and glutamate homeostasis. Dysregulation of Kir4.1 leads to altered neuronal activity, contributing to both chronic pain and mental health disorders. In chronic pain, downregulation of Kir4.1 impairs potassium buffering and glutamate clearance, increasing neuronal excitability and enhancing pain signaling through peripheral and central sensitization. In mental health disorders, impaired Kir4.1 function disrupts neurotrophic factor secretion and neuroinflammatory pathways, leading to mood disturbances. This review primarily summarizes findings from preclinical studies to examine the relationship between Kir4.1 and the pathogenesis of chronic pain and mental health disorders, discussing its molecular structure, expression patterns, and functional roles. Furthermore, we explore therapeutic strategies targeting Kir4.1, including pharmacological modulators and gene therapy approaches, emphasizing its potential as a novel therapeutic target.

The Unripe Carob Extract (Ceratonia siliqua L.) as a Potential Therapeutic Strategy to Fight Oxaliplatin-Induced Neuropathy

BACKGROUND

Oxaliplatin-induced neuropathy (OIN) is a severe painful condition that strongly affects the patient's quality of life and cannot be counteracted by the available drugs or adjuvants. Thus, several efforts are devoted to discovering substances that can revert or reduce OIN, including natural compounds. The carob tree, Ceratonia siliqua L., possesses several beneficial properties. However, its antalgic properties have not been substantially investigated and only a few investigations have been conducted on the unripe carob (up-CS) pods. Thus, the aims of this study were to evaluate for the first time the unripe variety of Apulian carob, chemically characterized and profiled as antioxidant potential of polyphenolic compounds as well as to investigate the ability of up-CS to reduce the neurotoxicity in a mouse model of oxaliplatin-induced neuropathic pain.

METHODS

By UHPLC-HRMS/MS analyses, 50 phenolic compounds, belonging mainly to n-galloylated glucoses and flavonoids were detected.

RESULTS

In a mouse model of oxaliplatin-induced neurotoxicity (2.4 mg/kg, 10 injections over two weeks), acute per os treatment with up-CS provoked a dose-dependent pain-relieving effect that completely counteracted oxaliplatin hypersensitivity at the dose of 200 mg/kg. Repeated oral administration of up-CS (100 mg/kg), concomitantly with oxaliplatin injection, exerted a protective effect against the development of thermal and mechanical allodynia. In addition, up-CS exerted a neuroprotective role against oxaliplatin-induced astrocytes activation in the spinal cord measured as GFAP-fluorescence intensity.

CONCLUSIONS

Overall, our study contributes to the knowledge on up-CS properties by highlighting its protective activity in the painful condition related to the administration of oxaliplatin.

One Nervous System: Critical Links Between Central and Peripheral Nervous System Health and Implications for Obesity and Diabetes

There are key differences between the central nervous system (CNS) (brain and spinal cord) and peripheral nervous system (PNS), such as glial cell types, whether there is protection by the blood-brain barrier, modes of synaptic connections, etc. However, there are many more similarities between these two arms of the nervous system, including neuronal structure and function, neuroimmune and neurovascular interactions, and, perhaps most essentially, the balance between neural plasticity (including processes like neuron survival, neurite outgrowth, synapse formation, gliogenesis) and neurodegeneration (neuronal death, peripheral neuropathies like axonopathy and demyelination). This article brings together current research evidence on shared mechanisms of nervous system health and disease between the CNS and PNS, particularly with metabolic diseases like obesity and diabetes. This evidence supports the claim that the two arms of the nervous system are critically linked and that previously understudied conditions of central neurodegeneration or peripheral neurodegeneration may actually be manifesting across the entire nervous system at the same time, through shared genetic and cellular mechanisms. This topic has been critically underexplored due to the research silos between studies of the brain and studies of peripheral nerves and an overemphasis on the brain in neuroscience as a field of study. There are likely shared and linked mechanisms for how neurons stay healthy versus undergo damage and disease among this one nervous system in the body-providing new opportunities for understanding neurological disease etiology and future development of neuroprotective therapeutics.

ARTICLE HIGHLIGHTS

The Possible Association of Burnout and Neuropathic Low Back Pain Among Hungarian Postal Workers: A Cross-Sectional Study

Objective

Burnout is an increasingly prevalent phenomenon, which can be associated with a wide range of mental and physical illnesses. There is also a possible connection between burnout and neuropathic low back pain, but the association is poorly studied.

Methods

The aim of our cross-sectional study was to analyze the prevalence and risk factors of chronic neuropathic low back pain taking many co-variates into account, such as burnout and its main determinants among postal workers. Demographic data, risk factors and concomitant diseases were recorded. Burnout was measured with the Mini Oldenburg Questionnaire (MOLBI), neuropathic low back pain was assessed by the painDETECT questionnaire, insomnia was detected by the Athen's Insomnia Scale and depression was measured by the Beck Depression Inventory.

Results

Three hundred sixty-eight males (35.6%) and six hundred sixty-six females (64.4%) participated in our study. Low back pain occured in 182 workers (17.6%), among them 36 workers (19.4%) had neuropathic low back pain, 56 (30.9%) had mixed pain and 90 (49.7%) workers had nociceptive low back pain. In a hierarchical regression analysis strong predictors of neuropathic low back pain included having secondary employment, depression, sleep disturbance and emotional exhaustion (main component of burnout).

Conclusion

This is among the first studies showing a possible association between burnout and neuropathic low back pain, highlighting the importance of adequate burnout screening and the implementation of interventions to avoid significant disabilities.

Pain and Cognition of Breast Cancer Survivors Treated with Chemotherapy: The Mediating Role of Depression

OBJECTIVES

While chemotherapy is the primary contributor to cancer-related cognitive impairment (CRCI), interindividual differences in CRCI are not well-understood. Studies suggest that breast cancer (BC) survivors who are in pain are more likely to experience depression, which in turn contributes to CRCI, although this hypothesis is not yet tested. Therefore, this study aimed to investigate the relationship between pain and CRCI among BC survivors and the mediation effect of depression on this relationship.

METHODS

As a secondary analysis of a descriptive cross-sectional study investigating fatigue and preferred types of fatigue self-management in BC survivors recruited from five tertiary hospitals in South Korea; of the 229 participants, data on 186 who received chemotherapy were analyzed. Study participants were aged between 20 and 69 years, diagnosed with stage I to III, and treated with chemotherapy and/or radiation therapy. Measurement was done with Korean versions of the Cognitive Failure Questionnaire (to assess CRCI), Brief Pain Inventory (for pain severity and interference on daily functioning), and C-ESD (for depression). To assess bivariate relationships between pain, depression, and CRCI, Pearson correlation was used. A mediation analysis was used to examine the effect of depression on CRCI.

RESULTS

Significant associations were found among pain, depression, and CRCI (all P < 0.01). Furthermore, a mediation effect of depression was found on the association between pain and CRCI (severity, β = 1.26, SE = 0.38, 95% confidence intervals [0.60, 2.08]; interference, β = 1.53, SE = 0.32, 95% confidence intervals [0.95, 2.20]).

CONCLUSION

Findings indicate that among BC survivors, those with higher pain tend to show higher depression and consequently had lower cognitive function.

IMPLICATION FOR NURSING PRACTICE

Oncology nurses may need to identify BC survivors with higher pain, and screening those survivors could be a strategy to identify those at higher risk for CRCI. Also, nurses should focus on managing depression to prevent and/or treat CRCI in BC survivors.

The involvement and significance of M2 macrophages in neuropathic pain following spinal cord injury: a systematic review

Neuropathic pain (NeP) is a type of persistent pain initiated by diseases or injuries of the nervous system. Although the underlying pathophysiological mechanisms of NeP are poorly understood, the immune system plays a key role in this condition. M2 macrophages have a key role in tissue healing and the reduction of inflammation. This systematic study aims to provide an overview of the role and importance of M2 macrophages in NeP after spinal cord injury (SCI). A comprehensive systematic review was conducted utilizing Scopus, PubMed, Embase, and ISI Web of Science databases. Two independent reviewers conducted the article selection. All publications examine the impact of M2 macrophages on NeP following spinal cord injuries. A quality assessment was conducted on bias entities that had been predetermined. Eleven papers met the criteria. According to the findings, focusing on immune cell polarization presents viable therapeutic options for treating NeP and enhancing recovery after SCI. M2 macrophages are essential for reducing neuropathic pain and promoting recovery after spinal cord injury. The modulation of M2 macrophages by a number of therapeutic approaches, including ivermectin-functionalized MWCNTs, isorhamnetin, Neuregulin-1 administration, TMEM16F inhibition, lentivirus-mediated delivery of anti-inflammatory cytokines, epigallocatechin-3-gallate, and red-light therapy promotes neuroregeneration, decreases neuroinflammatory cytokines, and reduces NeP. The results of these preclinical investigations must, however, be interpreted with caution, according to the quality assessment and risk of bias analysis of the studies that were included. Targeting M2 macrophages may have therapeutic benefits as they are essential for the management of NeP and recovery following spinal cord damage.

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.

Vortioxetine treatment for neuropathic pain in major depressive disorder: a three-month prospective study

Introduction and objective

Several studies revealed the therapeutic potential of vortioxetine (Vo) for pain. In this context, we aimed to evaluate the efficacy of Vo as a safe and tolerable novel pharmacologic agent in treating neuropathic pain (NP) in patients with major depressive disorder (MDD).

Materials and methods

The population of this cross-sectional prospective study consisted of all consecutive patients who were newly diagnosed with MDD by a neurology doctor at a psychiatric clinic and had NP for at least 6 months. All patients included in the sample were started on Vo treatment at 10 mg/day. They were assessed with Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), Self-Reported Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS), Douleur Neuropathique 4 Questions (DN4), Montreal Cognitive Assessment (MoCA), and Neuropathic Pain Impact on Quality of Life (NePIQoL) at the beginning of treatment and during the follow visits conducted at the end of the first, second and third months of the treatment. During these follow-up visits, patients were also queried about any side effects of Vo.

Results

The mean age of 50 patients included in the sample, 76% of whom were female, was 45.8 ± 11.2 years. There was a significant reduction in patients' NP complaints based on DN4 and S-LANNS, the subscales of NePIQoL, and significant improvement in MoCA. There was a significant reduction in patients' NP complaints based on DN4 and S-LANNS scores and a significant improvement in scores of the subscales of NePIQoL and MoCA.

Conclusion

The study's findings indicate that Vo, with its multiple mechanisms of action, can effectively treat NP independently of its mood-stabilizing effect. Future indication studies for Vo are needed to establish Vo's efficacy in treating NP.

Spinal nerve ligation: An experimental model to study neuropathic pain in rats and mice

Neuropathic pain, defined as the most terrible of all tortures, which a nerve wound may inflict, is a common chronic painful condition caused by gradual damage or dysfunction of the somatosensory nervous system. As with many chronic diseases, neuropathic pain has a profound economic and emotional impact worldwide and represents a major public health issue from a treatment standpoint. This condition involves multiple sensory symptoms including impaired transmission and perception of noxious stimuli, burning, shooting, spontaneous pain, mechanical or thermal allodynia and hyperalgesia. Current pharmacological options for the treatment of neuropathic pain are limited, ineffective and have unacceptable side effects. In this framework, a deeper understanding of the pathophysiology and molecular mechanisms associated with neuropathic pain is key to the development of promising new therapeutical approaches. For this purpose, a plethora of experimental models that mimic common clinical features of human neuropathic pain have been characterized in rodents, with the spinal nerve ligation (SNL) model being one of the most widely used. In this chapter, we provide a detailed surgical procedure of the SNL model used to induce neuropathic pain in rats and mice. We further describe the behavioral approaches used for stimulus-evoked and spontaneous pain assessment in rodents. Finally, we demonstrate that our SNL model induces multiple pain behaviors in rats and mice.

Effect of sex on psychological distress and fatigue over time in a prospective cohort of cancer survivors

BACKGROUND

Studies indicate a higher level of distress in women than men with cancer, but whether this difference is retained over time is unknown. We studied the frequency and level of distress and fatigue during time according to gender in a cohort of cancer survivors.

PATIENTS AND METHODS

In this prospective study, cancer survivors were invited to undergo a psychological session immediately before the medical visit. Distress was assessed by the distress thermometer, and fatigue was assessed by the ESAS-r scale. Patients underwent follow-up visits to assess changes over time.

RESULTS

A total of 305 patients and 568 visits were performed with a median follow-up of 15.8 months. At baseline, females, young age, and breast cancer patients had significantly higher distress. However, there was an increase in distress of 0.29 points every 6 months in males (95% CI, 0.09-0.50) versus no change in females (0.03 points, 95% CI, - 0.09-0.15; p-interaction = 0.01). The different behavior of cancer distress during time according to gender was more evident in subjects aged 68 or older due to increasing physical problems in men (p-interaction = 0.005). There was no change in fatigue with time according to sex.

CONCLUSIONS

Women, younger age, and breast cancer patients had increased cancer distress at the initial visit. However, women tend to stabilize during follow-up, whereas men tend to worsen their distress, especially because of physical and emotional problems, suggesting different coping capabilities.

TRIAL REGISTRATION

The study is registered at ClinicalTrials.gov NCT05122052.

IMPLICATIONS FOR CANCER SURVIVORS

Interventions aimed at improving recognition of emotions related to disease experience in male cancer survivors appear necessary.

Associations of frailty with symptoms, and HRQOL in older cancer survivors after cancer treatments: a systematic review and meta-analyses

PURPOSE

Frailty in older adult cancer survivors after cancer treatments is associated with various health outcomes. However, there is less agreement on how frailty affects symptoms and health-related quality of life (HRQOL). This systematic review and meta-analysis aimed to evaluate the current literature on frailty, symptoms, and HRQOL, as well as the associations of frailty with these factors in older adult cancer survivors with chemotherapy.

METHODS

A review was conducted on peer-reviewed publications from 2008 to 2023, using seven electronic databases. Meta-analyses were performed using random effects models to determine pooled effect estimates for frailty prevalence, symptom severity, and HRQOL scores.

RESULTS

A total of 26 studies involving older cancer survivors were included in the analysis. Most of these studies were conducted in Western countries and focused on White survivors, particularly those with breast cancer. The mean pooled prevalence of frailty was 43.5%. Among frail survivors, the most common symptoms reported after cancer treatments were pain (36.4%), neuropathy (34.1%), and fatigue (21.3%). Frailty was associated with higher pooled mean symptom severity (B = 1.23, p = 0.046) and lower functional HRQOL (B = - 0.31, p = 0.051, with marginal significance) after cancer treatments.

CONCLUSION

Frail older cancer survivors are at high risk of adverse symptoms and poor HRQOL after cancer treatment. Further research on screening for frailty is needed to prevent older adults from developing worse symptoms burden and maintain HRQOL. It is also essential to understand the mechanisms of the associations between frailty, symptoms and HRQOL in this population.

Activation of LXRs alleviates neuropathic pain-induced cognitive dysfunction by modulation of microglia polarization and synaptic plasticity via PI3K/AKT pathway

OBJECTIVE

Cognitive dysfunction is a common comorbidity in patients with chronic pain. Activation of Liver X receptors (LXRs) plays a potential role in improving cognitive disorders in central nervous diseases. In this study, we investigated the role of LXRs in cognitive deficits induced by neuropathic pain.

METHODS

We established the spared nerve injury (SNI) model to investigate pain-induced memory dysfunction. Pharmacological activation of LXRs with T0901317 or inhibition with GSK2033 was applied. PI3K inhibitor LY294002 was administered to explore the underlying mechanism of LXRs. Changes in neuroinflammation, microglia polarization, and synaptic plasticity were assessed using biochemical technologies.

RESULTS

We found that SNI-induced cognitive impairment was associated with reduced LXRβ expression, increased M1-phenotype microglia, decreased synaptic proteins, and inhibition of PI3K/AKT signaling pathway in the hippocampus. Activation of LXRs using T0901317 effectively alleviated SNI-induced cognitive impairment. Additionally, T0901317 promoted the polarization of microglia from M1 to M2, reduced pro-inflammatory cytokines, and upregulated synaptic proteins in the hippocampus. However, administration of GSK2033 or LY294002 abolished these protective effects of T0901317 in SNI mice.

CONCLUSIONS

LXRs activation alleviates neuropathic pain-induced cognitive impairment by modulating microglia polarization, neuroinflammation, and synaptic plasticity, at least partly via activation of PI3K/AKT signaling in the hippocampus. LXRs may be promising targets for addressing pain-related cognitive deficits.

Exploring venlafaxine effects on chronic vulvar pain: Changes in mood and pain regulation networks

The etiology of idiopathic pain conditions, such as Provoked vulvodynia (PV), is multifactorial. The efficiency of venlafaxine, serotonin-noradrenaline reuptake inhibitor (SNRIs) in modulating vulvar pain led to the hypothesis that PV might involve central mechanisms. Here, we investigate whether vulvar pain is associated with gene-expression changes in mood, stress and pain systems, including amygdala (Amg), medial prefrontal cortex (mPFC), and periaqueductal gray matter (PAG). Additionally, we examined the analgesic and anxiolytic effects of venlafaxine. We found that the development of chronic vulvar pain in an animal model of PV is associated by overexpression of genes related to neuronal-activity and neuroinflammation in the Amg, mPFC, and PAG. Additionally, changes in the expression of GABA and serotonin synthesis, and reuptake were noted in the Amg and mPFC. Unsurprisingly, anxiety-like behavior and emotional-disorder were observed in rats with chronic vulvar pain. Nevertheless, treatment with venlafaxine (37.5 mg/kg) for one month significantly improves the vulvar hypersensitivity, as well as reduces the anxiety level. More critically, the long-term gene expression adaptation in serotonin receptor and synthesis, GABA synthesis, neuroplasticity, and neuroinflammation in the Amg, mPFC, and PAG, were modulated by venlafaxine in rats with vulvar pain. Our findings suggest that vulvar hypersensitivity induced by inflammation might associated with gene expression changes in brain areas that are involved in mood, stress and pain regulation. These changes probably play a role in central sensitization, and anxiety. Strikingly, enhancing the activity of serotonin and noradrenaline via venlafaxine treatment in rats with vulvar pain induces analgesic and anxiolytic effects.

Case report: Neuropathic pain versus undesirable behavior in a Dachshund after hemilaminectomy surgery for an intervertebral disc extrusion

A 5.5 years-old male Dachshund was presented for evaluation because of undesirable behavior including barking, biting, sucking and licking the right-side flank, ventrally and slightly caudally to the level of the surgical incision 7 days after hemilaminectomy for a right-sided L1-2 intervertebral disc extrusion. The dog was being treated with oral gabapentin 10 mg/kg q8h. Repeat clinical examination on three occasions after post-operative discharge did not reveal any signs of hyperesthesia or neurological deficits and the behavior was not observed in the clinic during consultations. During a separate day of hospital admittance with the aim of evaluating for the presence or absence of the behavior, the dog also did not exhibit the behavior. Oral paracetamol 12 mg/kg q8h was added to medical treatment. When the dog was discharged and returned home, the behavior was immediately seen again. When the owners implemented verbal punishment, the behavior immediately ceased. The owner verbally corrected the dogs' behavior for two excitative days. Upon telephone consultation 3 days later, the owner reported that they only had observed three recurrences of the behavior that immediately ceased following verbal correction and did not recur thereafter. Oral analgesic medication was tapered and discontinued. No recurrence of the behavior was noticed during the next 2 months. The authors postulated the dog possibly expressed signs of neuropathic pain in the post-operative period, or that the behavior was of a "compulsive disorder-like" nature as it only occurred when the dog was at home and in the presence of the owner. The eventual outcome and result of verbal corrections implemented by the owner seem to support the latter. In conclusion, compulsive-like undesirable behavior should be considered a differential diagnosis in dogs in the post-operative period of procedures possibly associated with the development or expression of signs of neuropathic pain.

Cerebrolysin Attenuates Exacerbation of Neuropathic Pain, Blood-spinal Cord Barrier Breakdown and Cord Pathology Following Chronic Intoxication of Engineered Ag, Cu or Al (50-60 nm) Nanoparticles

Neuropathic pain is associated with abnormal sensations and/or pain induced by non-painful stimuli, i.e., allodynia causing burning or cold sensation, pinching of pins and needles like feeling, numbness, aching or itching. However, no suitable therapy exists to treat these pain syndromes. Our laboratory explored novel potential therapeutic strategies using a suitable composition of neurotrophic factors and active peptide fragments-Cerebrolysin (Ever Neuro Pharma, Austria) in alleviating neuropathic pain induced spinal cord pathology in a rat model. Neuropathic pain was produced by constrictions of L-5 spinal sensory nerves for 2-10 weeks period. In one group of rats cerebrolysin (2.5 or 5 ml/kg, i.v.) was administered once daily after 2 weeks until sacrifice (4, 8 and 10 weeks). Ag, Cu and Al NPs (50 mg/kg, i.p.) were delivered once daily for 1 week. Pain assessment using mechanical (Von Frey) or thermal (Hot-Plate) nociceptive showed hyperalgesia from 2 weeks until 10 weeks progressively that was exacerbated following Ag, Cu and Al NPs intoxication in nerve lesioned groups. Leakage of Evans blue and radioiodine across the blood-spinal cord barrier (BSCB) is seen from 4 to 10 weeks in the rostral and caudal cord segments associated with edema formation and cell injury. Immunohistochemistry of albumin and GFAP exhibited a close parallelism with BSCB leakage that was aggravated by NPs following nerve lesion. Light microscopy using Nissl stain exhibited profound neuronal damages in the cord. Transmission electron microcopy (TEM) show myelin vesiculation and synaptic damages in the cord that were exacerbated following NPs intoxication. Using ELISA spinal tissue exhibited increased albumin, glial fibrillary acidic protein (GFAP), myelin basic protein (MBP) and heat shock protein (HSP 72kD) upregulation together with cytokines TNF-α, IL-4, IL-6, IL-10 levels in nerve lesion that was exacerbated following NPs intoxication. Cerebrolysin treatment significantly reduced hyperalgesia and attenuated BSCB disruption, edema formation and cellular changes in nerve lesioned group. The levels of cytokines were also restored near normal levels with cerebrolysin treatment. Albumin, GFAP, MABP and HSP were also reduced in cerebrolysin treated group and thwarted neuronal damages, myelin vesiculation and cell injuries. These neuroprotective effects of cerebrolysin with higher doses were also effective in nerve lesioned rats with NPs intoxication. These observations suggest that cerebrolysin actively protects spinal cord pathology and hyperalgesia following nerve lesion and its exacerbation with metal NPs, not reported earlier.

The effects of major depression disorder on neurogenic thoracic outlet syndrome surgery outcomes

OBJECTIVES

Thoracic outlet syndrome (TOS) is a group of disorders caused by impingement of the neurovascular structures at the thoracic outlet. Neurogenic TOS (nTOS), which is thought to be caused by a compression of the brachial plexus, accounts for more than 90% of the cases. Although treatment for nTOS is successful through physiotherapy and/or surgical decompression, little is known about the impact of psychosocial factors, namely, major depressive disorder (MDD), on postoperative outcomes such as non-routine discharge (NRD). Here, we assess whether MDD predicts the type of discharge following nTOS surgical intervention.

METHODS

A retrospective analysis of the National Inpatient Sample database from the years 2005-2018 was performed. Using the International Classification of Diseases Clinical Modification, Ninth and Tenth revisions, patients who underwent a surgical intervention for nTOS were identified. Our primary outcome was to investigate the effects of MDD on nTOS patient disposition status after surgical management; secondary outcomes included analysis of total hospital charges and length of stay. NRD was defined as anything beyond discharge home without healthcare services. Univariate and multivariable logistic regression analyses were conducted to assess MDD and other potential independent predictors of NRD and prolonged hospital stay (> 2 days) following surgical intervention.

RESULTS

A total of 6099 patients were identified: 596 (9.77%) patients with MDD and 5503 (90.23%) without MDD. On average, patients with MDD were older (39.6 ± 12.0 years vs. 36.0 ± 13.0 years; p < 0.001), female (80.7% vs. 63.5%; p < 0.001), white (89.6% vs. 85.6%; p = 0.030), and on Medicare (9.6% vs 5.2%; p < 0.001). Univariate and multivariable logistic regression models identified MDD as an independent risk factor associated with a higher risk of NRD (adjusted odds ratio [aOR], 1.50; 95% confidence interval [CI], 1.0-2.2). Additionally, chronic kidney disease (aOR, 2.60; 95% CI, 1.2-5.4), postoperative complications (aOR, 1.87; 95% CI, 1.2-2.9), and Medicare (aOR, 2.95; 95% CI, 1.9-4.7) were statistically significant predictors for higher risk of NRD. However, MDD was not associated with prolonged hospital stay (aOR, 1.00; 95% CI, 0.8-1.2) or higher median of total charges (MDD group: $27,867 vs. non-MDD group: $28,123; p = 0.799).

CONCLUSION

Comorbid MDD was strongly associated with higher NRD rates following nTOS surgical intervention. MDD had no significant impact on length of hospital stay or total hospital charges. Additional prospective research is necessary in order to better evaluate the impact of MDD in patients with nTOS.

Drug repositioning: diacerein as a new therapeutic approach in a mice model of sciatic nerve injury

BACKGROUND

Peripheral nerve injuries negatively impact the quality of life of patients, with no effective treatment available that accelerates sensorimotor recovery and promotes functional improvement and pain relief. The aim of this study was to evaluate the effects of diacerein (DIA) in an experimental mice model of sciatic nerve crush.

METHOD

In this study, male Swiss mice were used, randomly separated into six groups as follows: FO (false-operated + vehicle); FO + DIA (false-operated + diacerein 30 mg/kg); SNI (sciatic nerve injury + vehicle); SNI + DIA in doses of 3, 10 and 30 mg/kg (sciatic nerve injury + treatment with diacerein in doses of 3-30 mg/kg). DIA or vehicle was administered 24 h after the surgical procedure, intragastrically, twice a day. The lesion of the right sciatic nerve was generated by crush.

RESULTS

We found that the treatment of animals with DIA accelerated sensorimotor recovery of the animal. In addition, animals in the sciatic nerve injury + vehicle (SNI) group showed hopelessness, anhedonia, and lack of well-being, which were significantly inhibited by DIA treatment. The SNI group showed a reduction in the diameters of nerve fibers, axons, and myelin sheaths, while DIA treatment recovered all these parameters. In addition, the treatment of animals with DIA prevented an increase the levels of interleukin (IL)-1β and a reduction in the levels of the brain-derived growth factor (BDNF).

CONCLUSIONS

Treatment with DIA reduces hypersensitivity and depression like behaviors in animals. Furthermore, DIA promotes functional recovery and regulates IL-1β and BDNF concentrations.

Comparison of two methods for extracting exosomes from the nucleus accumbens in mice

BACKGROUND

Exosomes bind to and are endocytosed by neurons of various brain regions. Methods for isolating and extracting exosomes from specific brain samples are critical. At present, the most important extractive methods for exosomes are Ultracentrifugation and exosome isolation kit extraction. Both of these extraction methods have applications in neuroscience. We compare these methods to reveal the differences.

METHODS

We sectioned the nucleus accumbens of mice, and isolated exosomes. A culture medium containing exosomes was extracted using ultracentrifugation (UC) and a total exosome isolation kit (TEI). The exosomes were examined using transmission electron microscopy (TEM), measurement regarding the diameter of the exosomes was done, and the thermal allodynia and western blotting analysis were also conducted, respectively.

RESULTS

Transmission electron microscopy observations showed that the ultracentrifugation samples had higher purity and fewer impurities than the kit samples. The results from the two methods were then compared with a number ratio regarding the percentage was not statistically significant. Marker protein tests showed that proteins were expressed under both methods. The thermal allodynia testing observed that the two extraction methods did not affect pain behavior regarding the detection. After the kit extraction method, there were substantial white subjects suspended by PBS.

CONCLUSION

Our study compared the different protocols regarding exosome extraction from the nucleus accumbens and compared the quality of two principal methods for exosome extraction from a culture medium containing exosomes. It was found that the extraction quality of exosomes by ultracentrifugation was better, but the technical difficulty was greater.

Functional investigation and two-sample Mendelian randomization study of neuropathic pain hub genes obtained by WGCNA analysis

Objective

Neuropathic pain as a complex chronic disease that occurs after neurological injury, however the underlying mechanisms are not clarified in detail, hence therapeutic options are limited. The purpose of this study was to explore potential hub genes for neuropathic pain and evaluate the clinical application of these genes in predicting neuropathic pain.

Methods

Differentially expressed analysis and weighted gene co-expression network analysis (WGCNA) was used to explore new neuropathic pain susceptibility modules and hub genes. KEGG and GO analyses was utilized to explore the potential role of these hub genes. Nomogram model and ROC curves was established to evaluate the diagnostic efficacy of hub genes. Additionally, the correlation of IL-2 with immune infiltration was explored. Finally, a Mendelian randomization study was conducted to determine the causal effect of IL-2 on neuropathic pain based on genome-wide association studies.

Results

WGCNA was performed to establish the networks of gene co-expression, screen for the most relevant module, and screen for 440 overlapping WGCNA-derived key genes. GO and KEGG pathway enrichment analyses demonstrated that the key genes were correlated with cytokine receptor binding, chemokine receptor binding, positive regulation of JAK-STAT cascade, chemokine-mediated signaling pathway, PI3K-AKT pathway and chemokine pathway. Through Cytoscape software, top ten up-regulated genes with high scores were IL2, SMELL, CCL4, CCR3, CXCL1, CCR1, HGF, CXCL2, GATA3, and CRP. In addition, nomogram model performed well in predicting neuropathic pain risk, and with the ROC curve, the model was showed to be effective in diagnosis. Finally, IL2 was selected and we observed that IL2 was causally associated with immune cell infiltrates in trigeminal neuralgia. In inverse variance weighting, we found that IL2 was associated with the risk of trigeminal neuralgia with an OR of 1.203 (95% CI = 1.004-1.443, p = 0.045).

Conclusion

We constructed a WGCNA-based co-expression network and identified neuropathic pain-related hub genes, which may offer further insight into pre-symptomatic diagnostic approaches and may be useful for the study of molecular mechanisms for understanding neuropathic pain risk genes.

Effects of 1-methyl-1, 2, 3, 4-tetrahydroisoquinoline on a diabetic neuropathic pain model

Background: Neuropathy is a prevalent and debilitating complication of poorly managed diabetes, contributing towards poor quality of life, amputation risk, and increased mortality. The available therapies for diabetic neuropathic pain (DPN) have limitations in terms of efficacy, tolerability and patient compliance. Dysfunction in the peripheral and central monoaminergic system has been evidenced in various types of neuropathic and acute pain. The objective of the present study was to investigate 1-methyl 1, 2, 3, 4-tetrahydroisoquinoline (1MeTIQ), an endogenous amine found in human brain with a known neuroprotective profile, in a model of streptozotocin (STZ) induced neuropathic pain. Methods: Diabetic neuropathy in male BALB/c mice was induced by intraperitoneal injection of a single dose of STZ (200 mg/kg). Upon development of DPN after 4 weeks, mice were investigated for mechanical allodynia (von Frey filament pressure test) and thermal hyperalgesia (tail immersion test). Ondansetron (1.0 mg/kg i.p.), naloxone (3.0 mg/kg i.p.) and yohimbine (2.0 mg/kg i.p.) were used to elucidate the possible mechanism involved. Postmortem frontal cortical, striatal and hippocampal tissues were dissected and evaluated for changes in levels of dopamine, noradrenaline and serotonin using High-Performance Liquid Chromatography (HPLC) with UV detection. Results: Acute administration of 1MeTIQ (15-45 mg/kg i.p.) reversed streptozotocin-induced diabetic neuropathic static mechanical allodynia (von Frey filament pressure test) and thermal hyperalgesia (tail immersion test), these outcomes being comparable to standard gabapentin. Furthermore, HPLC analysis revealed that STZ-diabetic mice expressed lower concentrations of serotonin in all three brain regions examined, while dopamine was diminished in the striatum and 1MeTIQ reversed all these neurotransmitter modifications. These findings suggest that the antihyperalgesic/antiallodynic activity of 1MeTIQ may be mediated in part via supraspinal opioidergic and monoaminergic modulation since they were naloxone, yohimbine and ondansetron reversible. Conclusion: It was also concluded that acute treatment with 1MeTIQ ameliorated STZ-induced mechanical allodynia and thermal hyperalgesia and restored brain regionally altered serotonin and dopamine concentrations which signify a potential for 1MeTIQ in the management of DPN.

Potential Roles of 5-HT3 Receptor Antagonists in Reducing Chemotherapy-induced Peripheral Neuropathy (CIPN)

5-HT₃ receptor antagonists corresponding to ondansetron, granisetron, tropisetron, and palonosetron are clinically accustomed to treating nausea and emesis in chemotherapy patients. However, current and previous studies reveal novel potentials of those ligands in other diseases involving the nervous system, such as addiction, pruritus, and neurological disorders, such as anxiety, psychosis, nociception, and cognitive function. This review gathers existing studies to support the role of 5-HT₃ receptors in CIPN modulation. It has been reported that chemotherapy drugs increase the 5-HT content that binds with the 5-HT₃ receptor, which later induces pain. As also shown in pre-clinical and clinical studies that various neuropathic pains could be blocked by the 5-HT₃ receptor antagonists, we proposed that 5-HT₃ receptor antagonists via 5- HT₃ receptors may also inhibit neuropathic pain induced by chemotherapy. Our review suggests that future studies focus more on the 5-HT₃ receptor antagonists and their modulation in CIPN to reduce the gap in the current pharmacotherapy for cancer-related pain.

A Comparison of the Differences in Postoperative Chronic Pain Between Video-Assisted and Robotic-Assisted Approaches in Thoracic Surgery

Background and objective In the last decade, there has been significant evolution in thoracic surgery with the advent of robotic surgery. In this study, we aimed to evaluate the incidence of postoperative chronic pain (for six months and beyond) in robotic and video-assisted approaches to analyze the long-term effects of the two different techniques. Methods This was a retrospective study involving 92 patients who underwent various thoracic operations between six months and two years preceding the study. Patients were classified into two groups based on the type of surgery: video-assisted (VATS) (n=51), and robotic-assisted (RATS) (n=41) thoracoscopic Surgery. We employed the EuroQol (EQ-5D-5L) questionnaire to assess the utility values in terms of five quality-of-life measures (self-care, pain/discomfort, mobility, anxiety/depression, and usual activities). Results In the VATS group, the median age was 68 years while it was 57 years in the RATS group (p=0.001). A higher proportion of patients in the VATS group had anatomical lung resection (lobectomy) compared to the RATS group: 61.2 vs. 41.6% respectively (p=0.005). However, the groups were well-matched on other patient characteristics such as relevant past medical history, underlying disease pathology, and final disease staging (if malignant), with no significant differences between groups observed regarding these traits. In the VATS group, 62.7% of patients were pain-free at the time of the questionnaire-based evaluation compared to 51.2% in the RATS group. Additionally, 25.5% vs. 39% of patients had mild pain in the VATS and RATS groups respectively. Neither of these differences was statistically significant. Conclusion Patients who undergo RATS are known to have better recovery and less pain compared to those who have VATS in the immediate postoperative period. However, our results did not find RATS to be superior to VATS in terms of long-term pain. Additionally, robotic surgery is associated with higher hospital costs. In light of these findings, further comparative studies between the two approaches are recommended, while strategies to reduce postoperative pain and financial cost should continue to be explored.

HMGB1 in the mPFC governs comorbid anxiety in neuropathic pain

Background

Whether neuroinflammation causes comorbid mood disorders in neuropathic pain remains elusive. Here we investigated the role of high mobility group box 1 protein (HMGB1), a proinflammatory cytokine, in the medial prefrontal cortex (mPFC) in anxiety comorbidity of neuropathic pain.

Methods

Neuropathic pain was induced by partial transection of the infraorbital nerve (p-IONX) or partial sciatic nerve ligation (PSL) in mice and evaluated by measuring nociceptive thresholds to mechanical and heat stimulation. Anxiety-like behaviors were assessed by elevated plus maze, light dark box and open field tests. Aversive or anti-aversive effect was detected by conditioned place preference test. Neuronal activity was evaluated by single-unit and patch clamp recordings. The contribution of mPFC pyramidal neurons to anxiety was further examined by selectively inhibiting them by optogenetics. HMGB1 expression was measured by immunohistochemistry and western blotting. Antagonism of HMGB1 was achieved by injecting anti-HMGB1 monoclonal antibody (mAb) intracerebrally or intraperitoneally.

Results

Anxiety-like behaviors were presented earlier after p-IONX than after PSL. HMGB1 expression was upregulated in the mPFC temporally in parallel to anxiety onset, rather than in other regions associated with anxiety. The upregulation of HMGB1 expression and its translocation from the nucleus to cytoplasm in the mPFC occurred predominantly in neurons and were accompanied with activation of microglia and astrocytes. Infusion of anti-HMGB1 mAb into the mPFC during the early and late phases after either p-IONX or PSL alleviated anxiety-like behaviors and aversion without changing pain sensitization, while local infusion of exogenous ds-HMGB1, the proinflammatory form of HMGB1, into the mPFC induced anxiety and aversion but not pain sensitization in naïve mice. In addition to reversing established pain sensitization and anxiety simultaneously, intraperitoneal injection of anti-HMGB1 mAb reduced HMGB1 upregulation and suppressed the hyperexcitability of layer 2/3 pyramidal neurons in the mPFC after p-IONX. Moreover, optogenetic inhibition of mPFC pyramidal neurons alleviated anxiety in p-IONX mice.

Conclusion

These results demonstrate that HMGB1 in the mPFC drives and maintains anxiety comorbidity in neuropathic pain by increasing the excitability of layer 2/3 pyramidal neurons, and justify antagonism of HMGB1, e.g., neutralization by mAb, as a promising therapeutic strategy for neuropathic pain with anxiety comorbidity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01475-z.

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.

Phenome-wide screening of the putative causal determinants of depression using genetic data

Depression is one of the most common mental health disorders and one of the top causes of disability throughout the world. The present study sought to identify putative causal associations between depression and hundreds of complex human traits through a genome-wide screening of genetic data and a hypothesis-free approach. We leveraged genome-wide association studies (GWAS) summary statistics for depression and 1504 complex traits and investigated potential causal relationships using the latent causal variable method. We identified 559 traits genetically correlated with depression risk at FDR < 5%. Of these, 46 were putative causal genetic determinants of depression, including lifestyle factors, diseases of the nervous system, respiratory disorders, diseases of the musculoskeletal system, traits related to the health of the gastrointestinal system, obesity, vitamin D levels, and the use of prescription medications, among others. No phenotypes were identified as potential outcomes of depression. Our results suggest that genetic liability to multiple complex traits may contribute to a higher risk for depression. In particular, we show a putative causal genetic effect of pain, obesity, and inflammation on depression. These findings provide novel insights into the potential causal determinants of depression and should be interpreted as testable hypotheses for future studies to confirm, which may facilitate the design of new prevention strategies to reduce depression's burden.

Analysis of Antidepressant, Benzodiazepine Anxiolytic, and Hypnotic Use When Treating Depression, Anxiety, and Aggression in Pain Clinic Patients Treated for Neuropathic Pain

Depression, anxiety, and aggression accompany neuropathic pain. Effective treatment of these comorbidities enhances the outcomes of pain management. Therefore, the study was designed to analyze the relationship between the intensity of depression, anxiety, and aggression and the pharmacotherapy applied in the daily practice of treating neuropathic pain. The aim of the study was to evaluate the frequency of using antidepressants (ADs), benzodiazepine anxiolytics (BDAs), and hypnotics, and the influence of administering these on the intensity of depression, anxiety, and aggression in patients diagnosed with neuropathic pain. A multi-center survey was conducted among 421 patients. An evaluation of the severity of depression, anxiety, and aggression was made using the Hospital Anxiety and Depression Scale—Modified Version (HADS-M). Among the patients treated due to neuropathic pain, ADs are used much more often than BDAs and hypnotics. Depression was well controlled, while anxiety was identified as a possible uncontrolled therapeutic problem in these patients, despite the correlation between the frequency of AD and hypnotics usage and the severity of anxiety. We also found that women show a higher level of intensity in both anxiety and depression, but this does not influence the frequency of their being administered ADs, BDAs, and hypnotics.

Effect of surgical damage to spinal nerve on dorsal root ganglion genes expression: Comprehensive analysis of differentially expressed genes

BACKGROUND

Neuropathic pain can cause significant physical and economic burden, and there are no effective long-term treatments. We conducted a bioinformatics analysis to identify mechanisms to determine strategies for more effective treatments of neuropathic pain.

METHOD

GSE24982 and GSE63442 microarray datasets were extracted from the Gene Expression Omnibus database to analyze transcriptome differences of neuropathic pain in the dorsal root ganglions (DRGs). We filtered the differentially expressed genes (DEGs) in the two datasets and conducted Gene Ontology (GO) functional analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of the shared DEGs. The Protein-Protein Interaction network was used to determine the hub genes, which were verified in the GSE30691 dataset. miRDB and miRWalk Databases were used to predict potential miRNA of the selected DEGs. We made the spinal nerve ligation (SNL) rat model and qPCR was used to verify the differential expression of hub genes.

RESULTS

A total of 182 overlapped DEGs were found between GSE24982 and GSE63442 datasets. The GO and KEGG analysis showed that the selected DEGs were enriched in infection, transmembrane transport of ion channels, and synaptic transmission. We identified seven hub genes (Atf3, Aif1, Ctss, Gfap, Scg2, Jun, and Vgf). qPCR verified the expression differences of the hub genes in the DRGs after SNL model. Predicted miRNA targeting each selected hub genes were identified.

CONCLUSIONS

Seven hub genes related to the pathogenesis of neuropathic pain and potential targeting miRNA were identified, expanding understanding of the mechanism of neuropathic pain and facilitating treatment development.

Does the Presence of Neuropathic Pain Influence the Response to Hyaluronic Acid in Patients with Knee Osteoarthritis?

OBJECTIVES

Up to 50% of patients with symptomatic knee osteoarthritis (OA) present with neuropathic pain (NP) features. We assessed the impact of NP according to DN4 (Douleurs Neuropathiques 4 questions) score on the response to intra-articular (IA) hyaluronic acid (HA) injections and the effects of HA injections on NP.

MATERIALS AND METHODS

We conducted a post hoc analysis from a multicenter, randomized, double-blind, noninferiority trial comparing the efficacy of 2 HA in symptomatic knee OA at 24 weeks. At baseline, demographic, anthropometric, radiologic data, and symptoms were recorded. The symptomatic effect of HA was assessed by VAS pain, patient global assessment (PGA), WOMAC, DN4, and OMERACT-OARSI response.

RESULTS

A total of 187 patients were included. NP according to DN4 score was present in 20 patients (10.7%) at baseline. Most common positive DN4 items were tingling (36.9%) and burning (36.4%). NP was associated with WOMAC pain score (P = 0.02). The presence of NP at baseline did not affect the symptomatic improvement after HA injections according to the VAS pain (P = 0.71), PGA (P = 050), WOMAC pain (P = 0.89), WOMAC function (P = 0.52), and rate of OMERACT-OARSI responders (P = 0.21). The prevalence of patients with NP decreased by 50% (n = 10) at 24 weeks after HA injections. Most improved DN4 items were itching (90%), hypoesthesia to pinprick (88%), and burning (50%).

CONCLUSION

In our study, NP was associated with pain severity, but did not influence the response to IA HA. On the other hand, HA injections reduced some NP features, especially itching, sting hypoesthesia, and burning.

Approach to Neuropathic Pain

Neuropathic pain is a common chief complaint encountered by neurologists and primary care providers. It is caused by disorders involving the somatosensory nervous system. The clinical evaluation of neuropathic pain is challenging and requires a multifaceted systematic approach with an emphasis on a thorough history and physical examination to identify characteristic signs and symptoms. Ancillary laboratory investigations, targeted imaging, and electrodiagnostic studies further help identify underlying etiologies to guide specific treatments. Management of neuropathic pain encompasses treating the underlying pathology as well as symptomatic control with nonpharmacological, pharmacological, and interventional therapies. Here, we present an approach to help evaluate patients with neuropathic pain.

Time course of effects of venlafaxine on migraine and generalized pruritus in a patient with depression

Venlafaxine has potential as a therapeutic option for patients with depressive disorder, migraine, and pruritus unresponsive to antihistamines.

Neuroinflammation as a possible link between attention-deficit/hyperactivity disorder (ADHD) and pain

Attention-deficit/hyperactivity disorder (ADHD) and pathological pain are two complex syndromes of multifactorial origin. Despite their prevalence and broad impacts, these conditions are seldom recognized and managed simultaneously. The co-existence of neuropsychiatric conditions (such as ADHD) and altered pain perception and chronic pain has been noted in children, and the comorbidity of ADHD and chronic pain is well documented in adults. Pathophysiological studies have suggested dysfunction of the dopaminergic system as a common neurochemical basis for comorbid ADHD and pain. Considerable evidence supports the role of neuroinflammation in the pathophysiology of both. We suggest that central neuroinflammation underlies altered pain perception and pain sensitization in persons with ADHD. Based on our hypothesis, targeting neuroinflammation may serve as a potential new therapeutic intervention to treat ADHD and comorbid pain in children and adolescents and a preventive strategy for the development of chronic pain in adults with ADHD.

Prospective observational study to examine health-related quality of life and develop models to predict long-term patient-reported outcomes 6 months after hospital discharge with blunt thoracic injuries

OBJECTIVE

This study aimed to examine the long-term outcomes and health-related quality of life in patients with blunt thoracic injuries over 6 months from hospital discharge and develop models to predict long-term patient-reported outcomes.

DESIGN

A prospective observational study using longitudinal survey design.

SETTING

The study recruitment was undertaken at 12 UK hospitals which represented diverse geographical locations and covered urban, suburban and rural areas across England and Wales.

PARTICIPANTS

337 patients admitted to hospital with blunt thoracic injuries were recruited between June 2018-October 2020.

METHODS

Participants completed a bank of two quality of life surveys (Short Form-12 (SF-12) and EuroQol 5-Dimensions 5-Levels) and two pain questionnaires (Brief Pain Inventory and painDETECT Questionnaire) at four time points over the first 6 months after discharge from hospital. A total of 211 (63%) participants completed the outcomes data at 6 months after hospital discharge.

OUTCOMES MEASURES

Three outcomes were measured using pre-existing and validated patient-reported outcome measures. Outcomes included: Poor physical function (SF-12 Physical Component Score); chronic pain (Brief Pain Inventory Pain Severity Score); and neuropathic pain (painDETECT Questionnaire).

RESULTS

Despite a trend towards improving physical functional and pain at 6 months, outcomes did not return to participants perceived baseline level of function. At 6 months after hospital discharge, 37% (n=77) of participants reported poor physical function; 36.5% (n=77) reported a chronic pain state; and 22% (n=47) reported pain with a neuropathic component. Predictive models were developed for each outcome highlighting important data collection requirements for predicting long-term outcomes in this population. Model diagnostics including calibration and discrimination statistics suggested good model fit in this development cohort.

CONCLUSIONS

This study identified the recovery trajectories for patients with blunt thoracic injuries over the first 6 months after hospital discharge and present prognostic models for three important outcomes which after external validation could be used as clinical risk stratification scores.

Clavulanic Acid Attenuating Effect on the Diabetic Neuropathic Pain in Rats

Diabetic neuropathy is one of the most common complications of diabetes mellitus. Excess glutamate release and oxidative stress are hypothesized to be involved in the pathophysiology of diabetes-induced neuropathy. This study was designed to investigate the effect of clavulanic acid (CLAV), a competitive beta-lactamase inhibitor, on the streptozocin (STZ)-induced neuropathic pain and possible mechanisms in the spinal cord of rats. Male Wistar rats were divided into naive group; control group which got a single dose of STZ (50 mg/kg, i.p.), as a model of diabetic neuropathic pain; prophylactic groups: animals received CLAV (10, 20 and 40 mg/kg, i.p.) 1 week after STZ for 10 days; and therapeutic group: animals received 20 mg/kg CLAV, 21 days after STZ for 10 days. Study of pain behaviors was started on days 0, 7, 14, 21, 28, 35 and 42 after STZ. The expression of the glutamate transport 1 (GLT1), genes of oxidative stress including inducible nitric oxide synthase (iNOS), proinflammatory cytokine, tumor necrosis factor alpha (TNF-α), as well as genes involved in the apoptosis including bcl2, bcl2-associated x (bax) were measured in the spinal cord tissue by Real Time PCR, on day 42. On day 21 post injection of STZ, diabetic animals showed significant mechanical allodynia, cold allodynia and thermal hyperalgesia. CLAV in all doses of 10, 20 and 40 mg/kg reduced symptoms of allodynia and hyperalgesia, in both prophylactic and therapeutic regimens. While iNOS, TNF-α, bax/bcl2 were found significantly overexpressed in spinal cord of diabetic animals, their expression in animals received CLAV had been reduced. In contrast, GLT1 that had decreased in the spinal cord of diabetic animals, significantly increased in those received CLAV. CLAV was found a promising candidate for reliving neuropathic pain in diabetes mellitus. Such beneficial effect of CLAV could be, in part, attributed to the increased expression of GLT 1, inhibition of nitrosative stress, anti-inflammation, and inhibition of some apoptotic mediators followed by administration into diabetic animals.

Decreased connexin43 expression in the hippocampus is related to the antidepressant effect of amitriptyline in neuropathic pain mice

Downregulation of astrocytic connexin43 (Cx43) has been observed in several brain regions in rodents and patients with depression. However, its specific role in this effect remains unknown. Moreover, chronic pain can induce depressive disorders. Therefore, the current study examined the relationship between Cx43 expression and depressive-like behavior in a neuropathic pain model. Neuropathic pain was induced by spared nerve injury (SNI) in mice. Depressive-like behavior was evaluated using the forced swim test. Expression of Cx43 in the hippocampus was evaluated using Western blotting and real-time PCR. SNI downregulated Cx43 protein in the contralateral hippocampus of mice, whereas expression of hippocampal Cx43 mRNA was not altered following SNI. Although SNI mice showed longer immobility time compared with sham mice during the forced swim test, duration of depressive-like behavior was not correlated with the expression of Cx43 in the hippocampus of SNI mice. Repeated intraperitoneal administration of amitriptyline ameliorated SNI-induced depressive-like behavior. Furthermore, the antidepressant effect of amitriptyline was correlated with decreased hippocampal Cx43 expression in SNI mice. The current findings suggest that the alteration of Cx43 expression in the hippocampus may not be involved in the induction of depressive disorder but may influence the efficacy of antidepressants. Therefore, the level of Cx43 expression in the hippocampus could be a key parameter to evaluate individual differences in antidepressant effects in patients with depressive disorder.

Neural Plasticity in the Brain during Neuropathic Pain

Neuropathic pain is an intractable chronic pain, caused by damage to the somatosensory nervous system. To date, treatment for neuropathic pain has limited effects. For the development of efficient therapeutic methods, it is essential to fully understand the pathological mechanisms of neuropathic pain. Besides abnormal sensitization in the periphery and spinal cord, accumulating evidence suggests that neural plasticity in the brain is also critical for the development and maintenance of this pain. Recent technological advances in the measurement and manipulation of neuronal activity allow us to understand maladaptive plastic changes in the brain during neuropathic pain more precisely and modulate brain activity to reverse pain states at the preclinical and clinical levels. In this review paper, we discuss the current understanding of pathological neural plasticity in the four pain-related brain areas: the primary somatosensory cortex, the anterior cingulate cortex, the periaqueductal gray, and the basal ganglia. We also discuss potential treatments for neuropathic pain based on the modulation of neural plasticity in these brain areas.

Neuropathic Low Back Pain and Burnout among Hungarian Workers

Burnout is an increasingly prevalent syndrome mainly involving those working in human services. Although it is categorized as an occupational phenomenon and not as a medical condition, it seems to be strongly associated with several diseases such as pain syndromes. However, no studies examined the association between neuropathic low back pain and burnout. This questionnaire-based study was carried out between April 2019 and March 2020 in three main sites among teachers, social workers and healthcare workers. Demographic criteria included age, gender, marital status, number of children, type of work, years spent with work, work schedule, legal relation, secondary employment. Included diseases were diabetes, hypertension, ischemic heart disease, generalized pain (pain involving more than one area of the body) and depression. Low back pain was assessed by the painDETECT questionnaire, burnout was measured with the Maslach Burnout Inventory (MBI) and depression was measured by the Beck Depression Inventory. Dysfunctional attitudes were also recorded. Overall, 1500 questionnaires were successfully delivered and 1141 responses received (response rate of 76%). Three hundred social workers, 399 teachers, 339 paramedics, 35 doctors and 68 medical attendants have completed our survey. In a multivariate analysis including of all factors (demographic criteria, burnout, depression, dysfunctional attitudes, comorbidity etc.) neuropathic low back pain was associated with age > 62 (OR = 3.981, p = 0.01), number of children ≥ 2 (OR = 2.638, p = 0.003), job type (being a social worker) (OR = 6.654, p < 0.001), burnout (OR = 2.577, p < 0.001), current depression (OR = 2.397, p < 0.001), and suffering from generalized pain (OR= 4.076, p < 0.001). This is the first study showing the association of burnout and neuropathic low back pain, which is the most common cause of disability. Based on our results neuropathic low back pain and burnout have similar risk factors and consequences which raises the possibility of similar pathophysiology.

Attenuation of ongoing neuropathic pain by peripheral acting opioid involves activation of central dopaminergic neurocircuitry

BACKGROUND AND PURPOSE

Ongoing neuropathic pain is one of the most challenging clinical problems which have detrimental effects on a patient's life quality. Conventional therapies for chronic neuropathic pain majorly includes centrally acting analgesics. Unfortunately, the unceasing use of these drugs results in adverse effects, such as CNS in-coordination, respiratory depression and substance use disorder. DALDA ([D-Arg², Lys⁴]-Dermorphin-(1-4)-amide), a peripherally acting opioid have been shown to possess potent analgesic activity without causing CNS toxicities in nerve-injured rats. However, the mechanism(s) underpinning DALDA induced-attenuation of ongoing neuropathic pain is yet to identify [1].

EXPERIMENTAL DESIGN

In this study, we have measured the in-silico ligand-receptor binding affinity of DALDA against potential inflammatory targets by utilizing glide module of schrödinger software. Effect of DALDA on oxido-inflammatory stress was evaluated in LPS-induced C6 glial cells. In-vitro studies were followed by the behavioral assessments, where effect of DALDA was measured in chronic constriction injured rats. To examine the effect of DALDA on dopaminergic neurotransmission, cerebrospinal fluid of nerve-injured rats was assessed using LC-MS/QToF (Liquid Chromatography-Mass spectrometry/ Quadrapole time of flight Analyzer).

RESULTS

DALDA has shown a good binding affinity with chemokine receptor type-2 (CCR2), chemokine CX3C receptor 1 (CX3CR1) and purinergic receptor (P2×4), major receptor subtypes involved in pain and inflammation. Findings from the in-vitro studies suggest that DALDA possesses potent anti-oxidant activity leading to inhibition of p38-MAPK pathway [1]. Moreover, the subcutaneous administration of DALDA leads to dose-dependent attenuation of thermal and mechanical hypersensitivity along with inhibition of neuroinflammatory mediators in serum and spinal cord of nerve-injured rats. Most importantly, DALDA treated neuropathic rats showed a preference for the DALDA-treated chamber, which was attenuated on pre-treatment with dopaminergic receptor antagonist, flupenthixol. LC-MS analysis further confirms the enhanced dopaminergic transmission in the brain of DALDA-treated neuropathic rats.

CONCLUSION

Our findings suggest that DALDA mediated attenuation of ongoing neuropathic pain may be associated with a decrease in spinal neuroinflammatory signalling and subsequent increase in the brain dopamine level; may serve a potential therapeutic for the treatment of ongoing neuropathic pain.

A Consideration of the Psychological Aspects to Managing Patients with Painful Diabetic Neuropathy: An Insight into Pain Management Services at a Tertiary Centre in the UK

Painful diabetic neuropathy (pDN) is characterised by both sensory and affective disturbances, suggesting a complex bidirectional relationship of neuropathic pain and mood disorders. Data on pDN indicate that neuropathic pain reduces quality of life, including mood and physical and social functioning. Depression and pain coping strategies such as catastrophising and social support predict pain severity. There is a significant and reciprocal relationship between depressed mood and increased pain. The key features of assessing people with neuropathic pain in relation to psychological aspects of their health are discussed in the context of management in a tertiary pain management centre (The Walton Centre, Liverpool, UK) including cognitive behavioural interventions amongst others to improve the quality of life in patients with pDN. We consider psychological issues as a factor influencing treatment and outcome in patients with pDN.

Vortioxetine as a new frontier in the treatment of chronic neuropathic pain: a review and update

Chronic neuropathic pain (CNP) is a disabling medical condition that impairs the health-related quality-of-life of affected patients. A high prevalence of anxiety, depression, sleep disturbance and cognitive impairment has frequently been reported in association with CNP, making the management of this disease complex and often multidisciplinary. Dual-acting agents such as selective serotonin and noradrenalin reuptake inhibitors (SNRIs) are considered particularly useful in the modulation of pain and in treatment of the mood disorders frequently associated with CNP. Recent evidence suggests that the top-down inhibitory control of pain involves the engagement and enhancement of descending endogenous opioidergic, cannabinoid and serotonergic systems, with the effect of serotonin being particularly related to the receptor subtypes that are preferentially activated; indeed serotonin induces analgesia via activation of 5-HT7 receptors and hyperalgesia via activation of 5-HT3 receptors. Vortioxetine (VO) is a novel multimodal serotonergic antidepressant with a unique mechanism of action. It has been demonstrated recently in experimental and clinical studies to have efficacy on pain hypersensitivity and on mood disorders. This drug inhibits the serotonin transporter with a high affinity, antagonises the 5-HT3, 5-HT1D and 5HT7 serotonin receptors, and activates the 5-HT1A and 5-HT1B receptors. In clinical studies, VO has proved effective at a dose of 10-20 mg/daily in short- and long-term treatment of patients with chronic orofacial pain, demonstrating a higher rate of clinical response and remission, a better acceptability, safety rate and tolerability, and a lower latency of action compared with other antidepressants. In the light of these recent findings, VO may be considered as a new pharmacological treatment also in relation to various types of CNP, particularly in elderly patients with concomitant mood disorders and cognitive impairment. The purpose of this review is to provide an up-to-date overview of the pharmacology and clinical applications of VO and to highlight its potential therapeutic properties and advantages in the management of CNP.

Pain anxiety and rehabilitation outcomes after acquired brain injury

Purpose: The purpose of this study was to examine pain anxiety after acquired brain injury (ABI) and its relationship to rehabilitation outcomes.Materials and Method: Participants consisted of 89 adults with an ABI participating in outpatient rehabilitation therapy. They completed a battery of neuropsychological tests at baseline along with surveys of mood, health-related self-efficacy, and pain anxiety. Separately, occupational therapists assessed basic and instrumental activities of daily living (ADLs) as well as therapy engagement across treatment after the sixth session.Results: Individuals who reported high pain anxiety had fewer years of formal education, lower self-efficacy, and more emotional distress than those with low pain anxiety. Although Blacks were about half (56%) of the study sample, they comprised the majority (73.1%) of individuals in the high pain anxiety group. Pain anxiety was negatively related to therapy engagement. Moderation analysis using linear regression indicated that pain anxiety moderated the influence of self-efficacy on basic ADLs.Conclusions: Pain anxiety, particularly when high, is negatively associated with rehabilitation outcomes for individuals with ABI. Among those with high pain anxiety, health-related self-efficacy is an important resilience characteristic to improve functional outcomes. In rehabilitation therapy, pain anxiety provides a novel intervention target to enhance ABI recovery.

When to consider "mixed pain"? The right questions can make a difference!

The term "mixed pain" is increasingly applied for specific clinical scenarios, such as low back pain, cancer pain and postsurgical pain, in which there "is a complex overlap of the different known pain types (nociceptive, neuropathic, nociplastic) in any combination, acting simultaneously and/or concurrently to cause pain in the same body area." Whether mixed pain is the manifestation of neuropathic and nociceptive mechanisms operating simultaneously or concurrently, or the result of an entirely independent pathophysiological mechanism - distinct from nociceptive, nociplastic and neuropathic pain - is currently unknown. At present, the diagnosis of mixed pain is made based on clinical judgement following detailed history-taking and thorough physical examination, rather than by formal confirmation following explicit screening or diagnostic criteria; this lack of formalized screening or diagnostic tools for mixed pain is problematic for physicians in primary care, who encounter patients with probable mixed pain states in their daily practice. This article outlines a methodical approach to clinical evaluation of patients presenting with acute, subacute or chronic pain, and to possibly identifying those who have mixed pain. The authors propose the use of nine simple key questions, which will provide the practicing clinician a framework for identifying the predominant pain mechanisms operating within the patient. A methodical, fairly rapid, and comprehensive assessment of a patient in chronic pain - particularly one suffering from pain with both nociceptive and neuropathic components - allows validation of their experience of chronic pain as a specific disease and, importantly, allows the institution of targeted treatment.

Long-lasting analgesic and neuroprotective action of the non-benzodiazepine anxiolytic etifoxine in a mouse model of neuropathic pain

Neuropathic pain is frequently associated with anxiety and major depressive disorders, which considerably impact the overall patient experience. Favoring GABAergic inhibition through the pain matrix has emerged as a promising strategy to restore proper processing of nociceptive and affective information in neuropathic pain states. In this context, the non-benzodiazepine anxiolytic etifoxine (EFX), known to amplify GABAergic inhibition through positive modulation of GABA_A receptors and neurosteroidogenesis, presents several advantages. Therefore, we sought to investigate the preclinical therapeutic potential of EFX on the somatosensory and affective components of neuropathic pain. Here, we used a murine model in which neuropathic pain was induced by the implantation of a compressive cuff around the sciatic nerve (mononeuropathy). We showed that the intraperitoneal EFX treatment for five consecutive days (50 mg/kg) relieved mechanical allodynia in a sustained manner. Besides its effect on evoked mechanical hypersensitivity, EFX also alleviated aversiveness of ongoing pain as well as anxiodepressive-like consequences of neuropathic pain following cuff-induced mononeuropathy. This effect was also seen 12 weeks after induction of the neuropathy when allodynia was no longer present. Analgesic and neuroprotective actions of EFX were also seen by the absence of neuropathic pain symptoms if a second sciatic nerve constriction injury was applied to the contralateral hindpaw. Mass spectrometry analysis revealed a normalization of brainstem serotonin levels in EFX-treated animals and an increase in norepinephrine. This study suggests that EFX presents promising therapeutic potential for the relief of both somatosensory and affective consequences of neuropathic pain, a beneficial effect that is likely to involve monoamine descending controls.

Patient-Centered Care in Psoriatic Arthritis-A Perspective on Inflammation, Disease Activity, and Psychosocial Factors

Psoriatic arthritis (PsA) is a seronegative spondyloarthropathy characterized by skin lesions, dactylitis, and enthesitis. Patients with PsA suffer from a variety of psychosocial difficulties and nonspecific symptoms early on in the disease course and continue to experience progressive disease due to delays in diagnosis and treatment. Symptoms initially viewed as somatization could lead to undertreatment and promote psychological distress, poor coping, and negative patient-provider relationships. Pain and fatigue are important complaints that affect the patient's perception and may need to be addressed with a multidisciplinary approach. Maladaptive cognitive responses can lead to a negative illness perception and impact patient beliefs and concerns over treatment, as well as nonadherence. An underlying inflammatory component in affective disorders has been examined, though whether and how it may interact mechanistically in PsA warrants interest. Cognitive behavioral therapy represents a nonpharmacological treatment modality that can be combined with cytokine-targeted therapy to address both somatic and psychological complaints. Future directions for research include: (1) Elucidating nonspecific manifestations (e.g., subclinical stage, differential with functional syndromes) of PsA and how they impact diagnosis and management; (2) characterizing immune-mediated components of mood disorders in PsA; and (3) whether a bidirectional approach with abrogating inflammation and psychotherapeutic support leads to improved outcomes.

The uses of resveratrol for neurological diseases treatment and insights for nanotechnology based-drug delivery systems

Neurological disorders have been growing in recent years and are highly prevalent globally. Resveratrol (RES) is a natural product from plant sources such as grape skins. This compound has shown biological activity in many diseases, in particular, those that act on the central nervous system. The mechanism of action and the key points in neurological disorders were described and show the targeted mechanism of action. Due to the insolubility of this compound; the use of nanotechnology-based systems has been proposed for the incorporation of RES and RES-loaded nanocarriers have been designed for intranasal administration, oral or parenteral routes to deliver it to the brain. In general, these nanosystems have shown to be effective in many studies, pharmacological and pharmacokinetic assays, as well as some cell studies. The outcomes show that RES has been reported in human clinical trials for some neurological diseases, although no studies were performed in humans using nanocarriers, animal and/or cellular models have been reported to show good results regarding therapeutics on neurological diseases. Thus, the use of this nutraceutical has shown true for neurological diseases and its loading into nanocarriers displaying good results on the stability, delivery and targeting to the brain.