Chronic Pain, Insomnia and their Mutual Maintenance: A Call for Cognitive Bias Research

Association between dysphagia risk and sleep quality in community-dwelling older adults: A cross-sectional study

Objectives

Exploring the effects of swallowing function on sleep quality could provide valuable insights into the potential impact of reduced swallowing function on sleep. However, pertinent studies are limited. Therefore, this study aimed to investigate the relationship between dysphagia risk and sleep health in community-dwelling older adults.

Methods

Data for this cross-sectional study were obtained from the Shizuoka and Daiko studies conducted as part of the Japan Multi-Institutional Collaborative Cohort Study. Information on demographics, overall lifestyle, dysphagia risk, as well as sleep quality, duration, satisfaction, and regularity, was obtained using a self-administered questionnaire. Dysphagia risk and sleep quality were assessed using the Dysphagia Risk Assessment Questionnaire for the Community-dwelling Elderly and the Japanese version of the Pittsburgh Sleep Questionnaire Index, respectively. Multivariate logistic regression, adjusted for covariates, was employed to assess the association between dysphagia risk and sleep health.

Results

Among the 3058 participants (1633 males, 1425 females) aged ≥60 years, 28.0 % exhibited dysphagia risk, and 19.1 % reported poor sleep quality. Those with dysphagia risk were more likely to experience poor sleep quality than those without dysphagia risk. In male participants, dysphagia was significantly associated with poor sleep quality, unsatisfactory sleep, and sleep irregularity, but was not significantly associated with unsatisfactory or irregular sleep in female participants. The Japanese version of the Pittsburgh Sleep Questionnaire Index components-subjective sleep quality, sleep latency, sleep disturbances, and daytime dysfunction-were associated with dysphagia risk in both sexes.

Conclusions

Dysphagia risk is associated with sleep quality in older individuals in Japan. Thus, preserving swallowing function may contribute to enhancing sleep quality.

Adolescent Girls' Musculoskeletal Pain is More Affected by Insomnia Than Boys, and Through Different Psychological Pathways

Prior research has established that insomnia is predictive of pain in adolescents and that psychological mechanisms have a crucial role in this relationship. Adolescent girls report more insomnia and pain than boys, yet little is known of gender differences in how insomnia influences pain. This study assessed gender differences in levels and trajectories of insomnia and pain during adolescence, and whether rumination and negative mood mediated the effect of insomnia on pain. Longitudinal survey data measured on 5 annual occasions (Nbaseline = 2,767) were analyzed in a multigroup longitudinal serial mediation model. A final model was generated with insomnia as the predictor, rumination and depressed mood as mediators, pain as the outcome, and gender as the grouping variable. The results showed that insomnia predicted pain in adolescents, with an effect 3.5 times larger in girls than boys. Depressed mood was the main mediator in boys. In girls, rumination was the only significant mediator. There were significant gender differences in the effects of insomnia on rumination and pain, and in the effects of rumination on depressed mood and pain, with stronger effects in girls. These results highlight that girls and boys should be considered separately when studying the relationship between insomnia and pain. PERSPECTIVE: Levels of insomnia and pain are progressively higher in adolescent girls than boys, across adolescence. The predictive strength of insomnia symptoms for future pain is 3.5 times greater in girls, with distinct gender-specific underlying pathways: rumination partially mediates this effect in girls, while depressed mood does so in boys.

Genetic overlap and causality between COVID-19 and multi-site chronic pain: the importance of immunity

Background

The existence of chronic pain increases susceptibility to virus and is now widely acknowledged as a prominent feature recognized as a major manifestation of long-term coronavirus disease 2019 (COVID-19) infection. Given the ongoing COVID-19 pandemic, it is imperative to explore the genetic associations between chronic pain and predisposition to COVID-19.

Methods

We conducted genetic analysis at the single nucleotide polymorphism (SNP), gene, and molecular levels using summary statistics of genome-wide association study (GWAS) and analyzed the drug targets by summary data-based Mendelian randomization analysis (SMR) to alleviate the multi-site chronic pain in COVID-19. Additionally, we performed a latent causal variable (LCV) method to investigate the causal relationship between chronic pain and susceptibility to COVID-19.

Results

The cross-trait meta-analysis identified 19 significant SNPs shared between COVID-19 and chronic pain. Coloc analysis indicated that the posterior probability of association (PPH4) for three loci was above 70% in both critical COVID-19 and COVID-19, with the corresponding top three SNPs being rs13135092, rs7588831, and rs13135092. A total of 482 significant overlapped genes were detected from MAGMA and CPASSOC results. Additionally, the gene ANAPC4 was identified as a potential drug target for treating chronic pain (P=7.66E-05) in COVID-19 (P=8.23E-03). Tissue enrichment analysis highlighted that the amygdala (P=7.81E-04) and prefrontal cortex (P=8.19E-05) as pivotal in regulating chronic pain of critical COVID-19. KEGG pathway enrichment further revealed the enrichment of pleiotropic genes in both COVID-19 (P=3.20E-03,Padjust=4.77E-02,hsa05171) and neurotrophic pathways (P=9.03E-04,Padjust =2.55E-02,hsa04621). Finally, the latent causal variable (LCV) model was applied to find the genetic component of critical COVID-19 was causal for multi-site chronic pain (P=0.015), with a genetic causality proportion (GCP) of was 0.60.

Conclusions

In this study, we identified several functional genes and underscored the pivotal role of the inflammatory system in the correlation between the paired traits. Notably, heat shock proteins emerged as potential objective biomarkers for chronic pain symptoms in individuals with COVID-19. Additionally, the ubiquitin system might play a role in mediating the impact of COVID-19 on chronic pain. These findings contribute to a more comprehensive understanding of the pleiotropy between COVID-19 and chronic pain, offering insights for therapeutic trials.

Higenamine inhibits acute and chronic inflammatory pain through modulation of TRPV4 channels

Pain is the cardinal symptom of many debilitating diseases and results in heavy health and economic burdens worldwide. Asarum (Asarum sieboldii Miq.) is a commonly used analgesic in Chinese medicine. However, the analgesic components and mechanisms of asarum in acute and chronic pain mice model remain unknown. In this study, we first generated asarum water extract and confirmed strong analgesic properties in mice in both the acute thermal and mechanical pain models, as well as in the complete Freund's adjuvant (CFA) induced chronic inflammatory pain model. Second, we identified higenamine as a major component of asarum and found that higenamine significantly inhibited thermal and mechanical induced acute pain and CFA induced chronic inflammatory pain. Then, using Trpv4-/- mice, we found that TRPV4 is necessary for CFA induced thermal and mechanical allodynia, and demonstrated that higenamine analgesia in the CFA model is partly through TRPV4 channel inhibition. Finally, we found that GSK1016790A, a TRPV4 agonist, induced calcium response was significantly inhibited by higenamine in both cultured DRG neurons and TRPV4 transfected HEK293 cells. Consistent with calcium imaging results, higenamine pretreatment also dose-dependently inhibited GSK1016790A induced acute pain. Taken together, our behavior and calcium imaging results demonstrate that the asarum component higenamine inhibits acute and chronic inflammatory pain by modulation of TRPV4 channels.

Assessing cognitive biases induced by acute formalin or hotplate treatment: an animal study using affective bias test

Pain, a universal and burdensome condition, influences numerous individuals worldwide. It encompasses sensory, emotional, and cognitive facets, with recent research placing a heightened emphasis on comprehending pain's impact on emotion and cognition. Cognitive bias, which encompasses attentional bias, interpretation bias, and memory bias, signifies the presence of cognitive distortions influenced by emotional factors. It has gained significant prominence in pain-related research. Human studies have shown that individuals experiencing pain exhibit cognitive bias. Similarly, animal studies have demonstrated cognitive bias in pain-induced states across various species and disease models. In this study, we aimed to investigate the memory bias displayed by rats experiencing acute pain, using the affective bias test (ABT) as a tool and administering either hotplate or formalin to induce acute pain. Our data showed that rats demonstrated a significant preference for the control treatment-related substrate over the substrate associated with formalin treatment (p < 0.001), an indication of the prominent memory bias stimulated by acute formalin injections. However, when exposed to substrates related to hotplate treatment and control treatment, the acute pain induced by the hotplate treatment failed to generate a statistically significant choice bias in rats (p = 0.674). Our study demonstrates that the negative emotions associated with acute pain can be reflected by memory bias in ABT, at least for formalin-induced acute pain. This finding will augment our comprehension of the emotional and cognitive aspects of acute pain.

Clinical Diagnosis and Treatment of Chronic Pain

More than 600 million people globally are estimated to be living with chronic pain. It is one of the most common complaints seen in an outpatient setting, with over half of patients complaining of pain during a visit. Failure to properly diagnose and manage chronic pain is associated with substantial morbidity and mortality, especially when opioids are involved. Furthermore, it is a tremendous financial strain on the healthcare system, as over USD 100 billion is spent yearly in the United States on healthcare costs related to pain management and opioids. This exceeds the costs of diabetes, heart disease, and cancer-related care combined. Being able to properly diagnose, manage, and treat chronic pain conditions can substantially lower morbidity, mortality, and healthcare costs in the United States. This review will outline the current definitions, biopsychosocial model, subclassifications, somatosensory assessments, imaging, clinical prediction models, and treatment modalities associated with chronic pain.

Modulation of visceral pain by brain nuclei and brain circuits and the role of acupuncture: a narrative review

Visceral pain is a complex and heterogeneous pain condition that is often associated with pain-related negative emotional states, including anxiety and depression, and can exert serious effects on a patient's physical and mental health. According to modeling stimulation protocols, the current animal models of visceral pain mainly include the mechanical dilatation model, the ischemic model, and the inflammatory model. Acupuncture can exert analgesic effects by integrating and interacting input signals from acupuncture points and the sites of pain in the central nervous system. The brain nuclei involved in regulating visceral pain mainly include the nucleus of the solitary tract, parabrachial nucleus (PBN), locus coeruleus (LC), rostral ventromedial medulla (RVM), anterior cingulate cortex (ACC), paraventricular nucleus (PVN), and the amygdala. The neural circuits involved are PBN-amygdala, LC-RVM, amygdala-insula, ACC-amygdala, claustrum-ACC, bed nucleus of the stria terminalis-PVN and the PVN-ventral lateral septum circuit. Signals generated by acupuncture can modulate the central structures and interconnected neural circuits of multiple brain regions, including the medulla oblongata, cerebral cortex, thalamus, and hypothalamus. This analgesic process also involves the participation of various neurotransmitters and/or receptors, such as 5-hydroxytryptamine, glutamate, and enkephalin. In addition, acupuncture can regulate visceral pain by influencing functional connections between different brain regions and regulating glucose metabolism. However, there are still some limitations in the research efforts focusing on the specific brain mechanisms associated with the effects of acupuncture on the alleviation of visceral pain. Further animal experiments and clinical studies are now needed to improve our understanding of this area.