The association of pain with protein inflammatory biomarkers: a review of the literature

Associations between sickness behavior, but not inflammatory cytokines, and psychiatric comorbidity in chronic pain

OBJECTIVES

Approximately one in five adults experiences chronic pain, often in co-occurrence with depression, insomnia, anxiety, and lower self-rated health. Elevated levels of cytokines, e.g. tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), interleukin 8 (IL-8), and interleukin 10 (IL-10), have been identified in patients with chronic pain. Depression, insufficient sleep, poor self-rated health, and pain intensity have also been associated with inflammatory biomarkers. This study aimed to investigate the interrelationships between inflammatory biomarkers and depression, insomnia, anxiety, self-rated health, sickness behavior, and pain intensity in patients with chronic pain.

METHODS

Self-report questionnaires and blood samples analyzed for plasma levels of inflammatory biomarkers were collected from 80 adult patients with chronic pain. Associations between inflammatory biomarkers (TNF-α, IL-6, IL-8, IL-10, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR)) and depression, insomnia, anxiety, self-rated health, sickness behavior, and pain intensity, were analyzed using bivariate Spearman rank correlation coefficients and regression analyses.

RESULTS

Participants were mainly women (72.5 %), with a mean age of 50.8 years, and a reported mean pain duration of 16.7 years. There were significant correlations between insomnia and CRP (rs =.26, p <.05); sex and ESR (rs =.29, p <.05); age and IL-6 (rs =.29, p <.05) and IL-8 (rs =.30, p <.05); BMI and IL-6 (rs =.50, p <.001), CRP (rs =.63, p <.001) and ESR (rs =.42, p <.001). Ratings of depression were positively and significantly related to ratings of sickness behavior and anxiety (β =.32 and β =.40, respectively), explaining 49 % of the total variance in depression ratings. Insomnia was positively and significantly related to sickness behavior (β =.37) explaining 31 % of the total variance in insomnia ratings. Inflammatory biomarkers, however, did not contribute significantly to the models.

CONCLUSIONS

Participants reported high levels of symptoms, yet the associations between these ratings and the inflammatory biomarkers were either absent or weak. Also, despite high levels of self-reported sickness behavior, overall the inflammatory status remained within the normal range. Ratings of sickness behavior contributed more than inflammatory markers in explaining ratings of depression and insomnia. The present results point to the complexity of chronic pain, and the challenges of identifying biomarkers that explain symptomatology.

Race-specific associations: inflammatory mediators and chronic low back pain

ABSTRACT

Chronic low back pain (cLBP) is a global health crisis that disproportionately burdens non-Hispanic Black (NHB) individuals, compared with those who identify as non-Hispanic White (NHW). Despite the growing personal and societal impact of cLBP, its biological underpinnings remain poorly understood. To elucidate the biological factors that underlie the racial disparities in cLBP, this study sought to determine whether inflammatory mediators associated with pain interference (PI), pain at rest (PAR), and movement-evoked pain (MEP) differ as a function of racial identity. Blood samples were collected from 156 individuals with cLBP (n = 98 NHB participants, n = 58 NHW participants). Enzyme-linked immunosorbent assay and multiplex assays were used to quantify concentrations of proinflammatory (fibrinogen, C-reactive protein [CRP], serum amyloid A, tumor necrosis factor α [TNF-α], and interleukin [IL]-1α, IL-1β, and IL-6) and anti-inflammatory markers (IL-4 and IL-13). Spearman rho correlations were used to assess associations among markers of inflammation and PI, PAR, and MEP using the Brief Pain Inventory-Short Form. Analyses revealed that for NHW patients, CRP, serum amyloid A, and IL-6 were positively associated with cLBP outcomes and IL-4 was inversely associated with PAR and MEP. However, for NHB patients, only IL-1α was positively associated with PAR. Our findings suggest that, while there are associations between inflammation and cLBP outcomes, the biomarkers that underlie the inflammation could very well differ as a function of racialized minority group. However, more research with racially inclusive samples is needed to elucidate the mechanisms that may contribute to racial disparities in cLBP.

Periodontitis is associated with decreased experimental pressure pain tolerance: The Tromsø Study 2015-2016

AIM

To assess the relationship between periodontitis and experimental pain tolerance.

MATERIALS AND METHODS

Participants from the population-based seventh survey of the Tromsø Study with data on periodontitis were included (n = 3666, 40-84 years old, 51.6% women). Pain tolerance was assessed through (i) pressure pain tolerance (PPT) test with a computerized cuff pressure algometry on the leg, and (ii) cold-pressor tolerance (CPT) test where one hand was placed in circulating 3°C water. Cox proportional hazard regression was used to assess the association between periodontitis and pain tolerance adjusted for age, sex, education, smoking and obesity.

RESULTS

In the fully adjusted model using the 2012 Centers for Disease Control/American Academy of Periodntology case definitions for surveillance of periodontitis, moderate (hazard ratio [HR] = 1.09; 95% confidence interval [CI]: 1.01, 1.18) and severe (HR = 1.25, 95% CI: 1.11, 1.42) periodontitis were associated with decreased PPT. Using the 2018 classification of periodontitis, having Stage II/III/IV periodontitis was significantly associated with decreased PPT (HR = 1.09; 95% CI: 1.01, 1.18) compared with having no or stage I periodontitis. There were no significant associations between periodontitis and CPT in fully adjusted models.

CONCLUSIONS

Moderate and severe periodontitis was associated with experimental PPT.

Effect of saline irrigation temperature difference on postoperative acute pain and hypothermia during biportal endoscopic spine surgery

BACKGROUND

Recently, enhanced recovery after surgery (ERAS) protocols have attracted attention; they emphasize on avoiding intraoperative hypothermia while performing lumbar fusion surgery. However, none of the studies have reported the protocol for determining the temperature of saline irrigation during biportal endoscopic spine surgery (BESS) procedure. This study evaluated the effectiveness of warm saline irrigation during BESS in acute postoperative pain and inflammatory reactions.

MATERIALS AND METHODS

Fifty-five patients who underwent BESS procedure were retrospectively analyzed for the incidence of perioperative hypothermia (< 36oC), postoperative inflammatory factors (white blood cells (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), interleukin-6 (IL-6), serum amyloid A (SAA)), and clinical outcomes (back visual analog scale (VAS) score, postoperative shivering). The patients were divided into the warm and cold saline irrigation groups.

RESULTS

Hemoglobin, WBC, ESR, creatine kinase, and creatine kinase-muscle brain levels did not significantly differ between the warm and cold saline groups. The mean CRP, IL-6, and SAA levels were significantly higher in the cold saline group than in the warm saline group (p = 0.0058, 0.0028, and 0.0246, respectively); back VAS scores were also higher with a statistically significant difference until two days postoperatively (p < 0.001). During the entire procedure, the body temperature was significantly lower in the cold saline irrigation group, but the hypothermia incidence rate significantly differed 30 min after the operation was started.

CONCLUSIONS

Using warm saline irrigation during BESS is beneficial for early recovery after surgery, as it is associated with reduced postoperative pain and complication rates.

Markers of Tissue Deterioration and Pain on Earth and in Space

Purpose

Pain is an understudied physiological effect of spaceflight. Changes in inflammatory and tissue degradation markers are often associated with painful conditions. Our aim was to evaluate the changes in markers associated with tissue deterioration after a short-term spaceflight.

Patients and Methods

Plasma levels of markers for systemic inflammation and tissue degeneration markers were assessed in two astronauts before and within 24 h after the 17-day Axiom Space AX-1 mission.

Results

After the spaceflight, C-reactive protein (CRP) was reduced in both astronauts, while INFγ, GM-CSF, TNFα, BDNF, and all measured interleukins were consistently increased. Chemokines demonstrated variable changes, with consistent positive changes in CCL3, 4, 8, 22 and CXCL8, 9, 10, and consistent negative change in CCL8. Markers associated with tissue degradation and bone turnover demonstrated consistent increases in MMP1, MMP13, NTX and OPG, and consistent decreases in MMP3 and MMP9.

Conclusion

Spaceflight induced changes in the markers of systemic inflammation, tissue deterioration, and bone resorption in two astronauts after a short, 17-day, which were often consistent with those observed in painful conditions on Earth. However, some differences, such as a consistent decrease in CRP, were noted. All records for the effect of space travel on human health are critical for improving our understanding of the effect of this unique environment on humans.

Effects of High-Intensity Interval Training (HIIT) on Patients with Musculoskeletal Disorders: A Systematic Review and Meta-Analysis with a Meta-Regression and Mapping Report

The aim was to assess the impact of high-intensity interval training (HIIT) on patients with musculoskeletal disorders. We conducted a search of Medline, Embase, PEDro, and Google Scholar. We conducted a meta-analysis to determine the effectiveness of HIIT on pain intensity, maximal oxygen consumption (VO₂ max), disability, and quality of life (QoL). We employed the GRADE and PEDro scales to rate the quality, certainty, and applicability of the evidence. Results showed significant differences in pain intensity, with a moderate clinical-effect (SMD = −0.73; 95% CI: −1.40–−0.06), and in VO₂ max, with a moderate clinical-effect (SMD = 0.69; 95% CI: 0.42–0.97). However, the meta-analysis showed no statistically significant results for disability (SMD = −0.34; 95% CI: −0.92–0.24) and QoL (SMD = 0.40; 95% CI: −0.80–1.60). We compared HIIT against other exercise models for reducing pain intensity and increasing VO₂ max. The meta-analysis showed no significant differences in favour of HIIT. Meta-regression analysis revealed that pain intensity scores were negatively associated with VO₂ max (R² = 82.99%, p = 0.003). There is low-moderate evidence that the HIIT intervention for patients with musculoskeletal disorders can reduce pain intensity and increase VO₂ max but has no effect on disability and QoL. Results also showed that HIIT was not superior to other exercise models in reducing pain intensity and increasing VO₂ max.

Inflammatory Markers and Radiotherapy Response in Patients With Painful Bone Metastases

CONTEXT

Inflammation is proposed to influence tumor response in radiotherapy (RT). Clinical studies to investigate the relationship between inflammatory markers and RT response is warranted to understand the variable RT efficacy in patients with painful bone metastases.

OBJECTIVES

To evaluate the association between inflammatory markers and analgesic response to RT in patients with painful bone metastases.

METHODS

Adult patients from 7 European study sites undergoing RT for painful bone metastases were included in this prospective and longitudinal analysis. The association between RT response and 17 inflammatory markers at baseline, as well as the association between RT response and the changes observed in inflammatory markers between baseline and three and eight weeks after RT, was analyzed with univariate regression analyses. Baseline analyses were adjusted for potential clinical predictors of RT response.

RESULTS

None of the inflammatory markers were significantly associated with an upcoming RT response in the analysis of 448 patients with complete baseline data. In patients available for follow-up, the three-week change in TNF (P 0.017), IL-8 (P 0.028), IP-10 (P 0.032), eotaxin (P 0.043), G-CSF (P 0.033) and MCP-1 (P 0.002) were positively associated with RT response, while the three-week change in CRP (P 0.006) was negatively associated.

CONCLUSION

Results from this study show an association between RT response and change in pro-inflammatory mediators and indicate that inflammation may be important to achieve an analgesic RT response in patients with painful bone metastases. None of the investigated inflammatory markers were found to be pre-treatment predictors of RT response.

Integrating the Gut Microbiome and Stress-Diathesis to Explore Post-Trauma Recovery: An Updated Model

Musculoskeletal conditions of traumatic and non-traumatic origin represent an ongoing health challenge. While the last three decades have seen significant advancement in our understanding of musculoskeletal conditions, the mechanisms of a delayed or lack of recovery are still a mystery. Here, we present an expansion of the integrated stress-diathesis model through the inclusion of the gut microbiome. Connecting the microbiome with known adverse neurobiologic, microbiologic and pathophysiologic sequelae following an injury, trauma or stressful event may help improve our knowledge of the pathogenesis of poor recovery. Such knowledge could provide a foundation for the exploration and development of more effective interventions to prevent the transition from acute to chronic pain.

Toward Composite Pain Biomarkers of Neuropathic Pain—Focus on Peripheral Neuropathic Pain

Chronic pain affects ~10–20% of the U.S. population with an estimated annual cost of $600 billion, the most significant economic cost of any disease to-date. Neuropathic pain is a type of chronic pain that is particularly difficult to manage and leads to significant disability and poor quality of life. Pain biomarkers offer the possibility to develop objective pain-related indicators that may help diagnose, treat, and improve the understanding of neuropathic pain pathophysiology. We review neuropathic pain mechanisms related to opiates, inflammation, and endocannabinoids with the objective of identifying composite biomarkers of neuropathic pain. In the literature, pain biomarkers typically are divided into physiological non-imaging pain biomarkers and brain imaging pain biomarkers. We review both types of biomarker types with the goal of identifying composite pain biomarkers that may improve recognition and treatment of neuropathic pain.

Individuals with both higher recent negative affect and physical pain have higher levels of C-reactive protein

Conceptualizing physical pain and negative affect as potentially interactive, we hypothesized that higher levels of peripheral inflammatory markers would be observed consistently only among individuals with both higher negative affect and pain symptomatology. Participants were generally healthy midlife adults from the Bronx, NY (N ​= ​212, M_age ​= ​46.77; 60.8% Black, 25.5% Hispanic/Latina/o) recruited as part of a larger study. Key measures were: reported pain intensity and pain interference at baseline, recent negative affect averaged from self-reports 5x/day for 7 days, and peripheral inflammatory markers (C-reactive protein [CRP] and a composite cytokine measure based on seven cytokines). Controlling for age, BMI, gender, and education, recent negative affect significantly interacted with both pain variables to explain variance in CRP, with higher CRP levels observed only in individuals with both higher negative affect and either higher pain intensity or pain interference. These findings contribute to an emerging literature suggesting that negative affect, pain, and inflammation are related in important and complex ways.

Baseline Pro-Inflammatory Cytokine Levels Moderate Psychological Inflexibility in Behavioral Treatment for Chronic Pain

Background: The medical and scientific communities struggle to understand chronic pain and find effective treatments. Multimodal approaches are encouraging but show significant individual differences. Methods: Seventy-eight persons (56 women) with chronic pain received Acceptance and Commitment Therapy and provided blood samples before and after treatment. The participants completed surveys with the blood sampling. Blood plasma was analyzed for IL-6 and TNF-α levels with the Olink Inflammation Panel (Olink Bioscience Uppsala, Sweden). The treatment effects and moderating effects of low-grade inflammation on changes in outcomes were analyzed using linear mixed models. Results: Pain interference (p < 0.001) and psychological inflexibility (p < 0.001) improved significantly during treatment, but pain intensity did not (p = 0.078). Cytokine levels did not change over the course of the treatment (IL-6/TNF-α p = 0.086/0.672). Mean baseline levels of IL-6 and TNF-α moderated improvement in psychological inflexibility during the course of treatment (p = 0.044), but cytokine levels did not moderate changes in pain interference (p = 0.205) or pain intensity (p = 0.536). Conclusions: Higher baseline inflammation levels were related to less improvement in psychological inflexibility. Low-grade inflammation may be one factor underlying the variability in behavioral treatment in chronic pain.

Relevance of cortisol and copeptin blood concentration changes in an experimental pain model

The effect of pain and analgesics on stress biomarkers is not well studied. We evaluated the effect of acute pain and analgesics on serum cortisol and copeptin in an experimental pain model in healthy volunteers. Healthy volunteers presented at 8 a.m. for an experimental pain stimulation. Cortisol and copeptin levels were measured before, during and after electrophysiological stimulation, first before and then during opioid delivery. Difference in biomarker levels compared to baseline levels was calculated, and potential influencing factors were evaluated by linear regression analysis. Cortisol decreased by 13% during the 10 min of rest at baseline, but copeptin did not change significantly. Cortisol had a median decrease of −24% or −83 nmol/l (−44 to −124 nmol/l, p = 0.0002) during the electrophysiological stimulation training session, while the median difference for copeptin was −22% or −1.01 pmol/l (−2.35 to 0.08 pmol/l, p = 0.0003). After administration of opioids, cortisol did not decrease but increased by 3% (p = 0.043), indicating an increasing opioids effect on cortisol. This effect was not visible for copeptin (median change −0.003 pmol/l (−0.50 to 0.24), p = 0.45). In this experimental pain model performed in the morning, moderate pain did not have a relevant effect on cortisol or copeptin levels, whereas opioids led to a discrete peak of cortisol.

Clinicaltrials.gov identifier: NCT01975753 (registered on November 5, 2013, before start of recruitment).

Evaluating the construct validity and internal consistency of the Sickness Questionnaire in a Swedish sample of adults with longstanding pain

OBJECTIVES

Low-grade inflammation is a possible contributing factor in the development and persistence of chronic primary pain syndromes. Related to inflammatory activity is sickness behavior, a set of behavioral responses including increased pain sensitivity, fatigue, malaise, fever, loss of appetite, as well as depressive behavior and anhedonia. To capture these behavioral responses and their relation to longstanding pain, psychometrically sound self-report questionnaires are needed. The Sickness Questionnaire (SicknessQ) was developed to assess self-reported sickness behavior based on studies on acute immune activation while maintaining relevance for persistent conditions. The aim of the current study was to evaluate aspects of the validity and reliability of the SicknessQ in a Swedish sample of persons with longstanding pain.

METHODS

Aspects of construct validity were evaluated by means of performing a confirmatory factor analysis (CFA) (testing structural validity) and by relevant hypothesis testing i.e., that ratings of sickness behavior in combination with other related factors (e.g., depression and anxiety) would be significantly related to ratings of avoidance. Reliability was evaluated by means of analyzing the internal consistency of items.

RESULTS

Following the CFA, a non-significant Chi-Square test (χ2 [32, N=190] = 42.95, p=0.094) indicated perfect model fit. Also, the relative fit indices supported adequate model fit (CFI = 0.978; TLI = 0.969; RMSEA = 0.0430). Sickness behavior (p<0.0001), depression (p<0.05) and pain duration (p<0.05) significantly contributed to the regression model, explaining 45% of the total variance in avoidance. Internal consistency was adequate, as indicated by a Cronbach's α value of 0.82 for the entire questionnaire.

CONCLUSIONS

Results indicate that the SicknessQ has adequate structural validity as well as adequate internal consistency, and is significantly associated with avoidance. The SicknessQ appears to have utility as a self-report questionnaire to assess symptoms of sickness behavior for adults with longstanding pain.

TGF-β1 in plasma and cerebrospinal fluid can be used as a biological indicator of chronic pain in patients with osteoarthritis

Introduction

Previous studies have demonstrated that cytokines, transforming growth factor (TGF-β1), and brain-derived neurotrophic factor (BDNF) can impact the intensity of pain in rodents. However, the roles of cytokines, TGF-β1 and BDNF in humans with chronic pain in osteoarthritis remains unclear, and no comparison between plasma and central cerebral spinal fluid (CSF) has been conducted.

Methods

Patients with osteoarthritis who were scheduled to receive spinal anesthesia were enrolled. The intensity of pain was evaluated with a visual analogue scale (VAS). In addition, patients with genitourinary system (GU) diseases and without obvious pain (VAS 0–1) were included as a comparison (control) group. The levels of TGF-β1, BDNF, tumor necrosis factor-α (TNF-α), and interleukin (IL)-8 within the CSF and plasma were collected and evaluated before surgery.

Results

The plasma and CSF TGF-β1 levels were significantly lower in the osteoarthritis patients with pain (VAS ≥ 3) than in the GU control patients. Downregulation of plasma BDNF was also found in osteoarthritis patients with pain. The Spearman correlation analysis showed that the VAS pain scores were significantly negatively correlated with the levels of TGF-β1 in the CSF of patients with osteoarthritis. However, there was no significant correlations between the pain scores and the levels of BDNF, TNF-α, and IL-8 in either the CSF or plasma.

Conclusions

TGF-β1 but not BDNF, TNF-α, or IL-8 may be an important biological indicator in the CSF of osteoarthritis patients with chronic pain.

Association Between Sleep Quality and Pain Intensity in Mild Patients with COPD: A Community Study

Purpose

Poor sleep quality and pain were common and had been proved as an important influenced factor of quality of life for patients with COPD. The association of sleep quality with pain has been observed in other population but remains unclear in mild patients with COPD from a community setting.

Methods

A cross-sectional study was conducted to include eligible mild patients with COPD in Pudong New District of Shanghai. A structured questionnaire was used to collect general and clinical information for the patients. The Chinese version of Pittsburgh Sleep Quality Index (PSQI) and the short form of McGill Pain Questionnaire (SF-MPQ) was used to assess sleep quality and intensity of pain. Logistic regression was performed to test the association between sleeping quality and pain intensity.

Results

Two hundred and sixty-four patients with COPD, with an average age of 64 years (SD 5.78 years), were enrolled, and of 52% were women. Seventy-one (26.9%) participants reported at least one exacerbation during the past year. About 28.2% of the patients were classified as having poor sleep quality. Sleep quality was significantly associated with PRI score (adjusted odds ratio (ORad)=2.16, 95% CI: 1.16–4.00) and PPI rank (ORad=1.90, 95% CI: 1.08–3.34). People with daytime disturbance were more likely to have pain (ORad =2.03, 95% CI: 1.18–3.50).

Conclusion

Poor sleep quality was common in mild patients with COPD in community and was associated with higher pain intensity. Pain may involve an impairment of sleep quality.

Automated home-cage monitoring as a potential measure of sickness behaviors and pain-like behaviors in LPS-treated mice

The use of endotoxin, such as lipopolysaccharide (LPS) as a model of sickness behavior, has attracted recent attention. To objectively investigate sickness behavior along with its pain-like behaviors in LPS-treated mice, the behavioral measurement requires accurate methods, which reflects clinical relevance. While reflexive pain response tests have been used for decades for pain assessment, its accuracy and clinical relevance remain problematic. Hence, we used automated home-cage monitoring LABORAS to evaluate spontaneous locomotive behaviors in LPS-induced mice. LPS-treated mice displayed sickness behaviors including pain-like behaviors in automated home-cage monitoring characterized by decreased mobile behaviors (climbing, locomotion, rearing) and increased immobility compared to that of the control group in both short- and long-term locomotive assessments. Here, in short-term measurement, both in the open-field test and automated home-cage monitoring, mice demonstrated impaired locomotive behaviors. We also assessed 24 h long-term locomotor activity in the home-cage system, which profiled the diurnal behaviors of LPS-stimulated mice. The results demonstrated significant behavioral impairment in LPS-stimulated mice compared to the control mice in both light and dark phases. However, the difference is more evident in the dark phase compared to the light phase owing to the nocturnal activity of mice. In addition, the administration of indomethacin as a pharmacological intervention improved sickness behaviors in the open-field test as well as automated home-cage monitoring, confirming that automated home-cage monitoring could be potentially useful in pharmacological screening. Together, our results demonstrate that automated home-cage monitoring could be a feasible alternative to conventional methods, such as the open-field test and combining several behavioral assessments may provide a better understanding of sickness behavior and pain-like behaviors in LPS-treated mice.

Applying the NIA Health Disparities Research Framework to Identify Needs and Opportunities in Chronic Musculoskeletal Pain Research

Disparities in the experience of chronic musculoskeletal pain in the United States stem from a confluence of a broad array of factors. Organized within the National Institute on Aging Health Disparity Research Framework, a literature review was completed to evaluate what is known and what is needed to move chronic musculoskeletal pain research forward specific to disproportionately affected populations. Peer-reviewed studies published in English, on human adults, from 2000 to 2019, and conducted in the United States were extracted from PubMed and Web of Science. Articles were reviewed for key words that focused on underrepresented ethnic/race groups with chronic musculoskeletal pain applying health factor terms identified in the NIAHealth Disparity Research Framework four levels of analysis: 1) environmental, 2) sociocultural, 3) behavioral, and 4) biological. A total of 52 articles met inclusion criteria. There were limited publications specific to underrepresented ethnic/race groups with chronic musculoskeletal pain across all levels with particular research gaps under sociocultural and biological categories. Current limitations in evidence may be supplemented by a foundation of findings specific to the broader topic of "chronic pain" which provides guidance for future investigations. Study designs including a focus on protective factors and multiple levels of analyses would be particularly meritorious. PERSPECTIVE: Chronic musculoskeletal pain unequally burdens underrepresented ethnic/race groups. In order to move research forward and to systematically investigate the complex array of factors contributing toward health disparities, an organized approach is necessary. Applying the NIA Health Disparities Research Framework, an overview of the current state of evidence specific to chronic musculoskeletal pain and underrepresented ethnic/race groups is provided with future directions identified.

The in-utero experience of piglets born from sows with lameness shapes their life trajectory

Experiences during gestation can alter the mother's behavior and physiology, thereby potentially affecting the behavioral and physiological development of the offspring. In livestock, one common challenge for pregnant animals is lameness: a multifactorial condition that causes pain, stress, resulting in poor welfare outcomes. Since maternal pain can affect offspring development, we aimed to quantify the behavioral response in 142 piglets born from sows with different degrees of lameness during pregnancy. Gait scores of 22 pregnant group-housed sows were assessed six times at 2-week intervals. Lameness scores varied from 0 (no lameness) to 5 (most severe lameness score). Saliva samples and behavior were assessed in the sows throughout pregnancy. Sows were moved to individual farrowing pens and placental tissue was collected for glucocorticoid assessment. At 28 days of age, piglets were weaned, weighed, and regrouped by body size and sex. Skin lesions were counted for each piglet on days 28, 29, and 30 after birth. During open field and novel object tests on day 30, the vocalization and activity levels were evaluated. Piglet data were grouped by the lameness score of the sows as G1 (without lameness), G2 (moderate lameness), and G3 (severe lameness). Data analysis included ANOVA or Kruskal-Wallis tests and pairwise comparisons which were performed using Tukey and Kramer (Nemenyi) test with Tukey-Dist approximation for independent samples. G2 piglets were heavier than G3 at weaning. G1 piglets had fewer skin lesions at days 28 and 29 than G2 piglets. Moreover, G1 piglets vocalized more than G2 when they were subjected to the combined open field and novel object test. We did not identify differences among sows showing different lameness scores in the concentration of placental or salivary glucocorticoids. Lameness in pregnant sows altered the offspring's weight gain, number of skin lesions and vocalizations, together showing evidence that lameness in sows affect offspring performance and behavior.

Relationship Between Blood Cytokine Levels, Psychological Comorbidity, and Widespreadness of Pain in Chronic Pelvic Pain

Background: Low-grade inflammation has been implicated in the etiology of depression, long-term fatigue and chronic pain. TNFα and IL-6 are perhaps the most studied pro-inflammatory cytokines in the field of psychoneuroimmunology. The purpose of our study was to further investigate these relationships in patients with chronic pelvic pain specifically. Using plasma samples from a large, well-described cohort of patients with pelvic pain and healthy controls via the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network, we examined the relationship between TNFα and IL-6 and comorbid psychological symptoms. We also investigated the relationship between IL-8 and GM-CSF, and widespreadness of pain. Methods: We included baseline blood samples in the analyses, 261 patients (148 women) and 110 healthy controls (74 women). Fourteen pro- and anti-inflammatory or regulatory cytokines were analyzed in a Luminex^® xMAP^® high-sensitivity assay. We used regression models that accounted for known factors associated with the outcome variables to determine the relationship between cytokine levels and clinical measures. Results: There were no statistical differences in cytokine levels between patients and healthy controls when controlling for age. In patients, TNFα was significantly associated with levels of fatigue (p = 0.026), but not with pain intensity or depression. IL-6 was not significantly related to any of the outcome variables. Women with pelvic pain showed a negative relationship between IL-8 and widespreadness of pain, while men did not (p = 0.003). For both sexes, GM-CSF was positively related to widespreadness of pain (p = 0.039). Conclusion: Our results do not suggest low-grade systemic inflammation in chronic pelvic pain. Higher TNFα blood levels were related to higher fatigue ratings, while higher systemic GM-CSF levels predicted more widespread pain. Our study further suggests a potentially protective role of IL-8 with regard to with regard to the widepreadness of pain in the body, at least for women.

Telomere lengths in women treated for breast cancer show associations with chemotherapy, pain symptoms, and cognitive domain measures: a longitudinal study

Background

Survival rates for breast cancer (BC) have improved, but quality of life post-diagnosis/treatment can be adversely affected, with survivors reporting a constellation of psychoneurological symptoms (PNS) including stress, anxiety, depression, pain, fatigue, sleep disturbance, and cognitive dysfunction.

Methods

To assess a potential relationship between telomere length (TL) and the development/persistence of PNS, we longitudinally studied 70 women (ages 23–71) with early stage BC (I-IIIA) at 5 time-points: prior to treatment (baseline), the mid-point of their chemotherapy cycle, 6 months, 1 year, and 2 years following the initiation of chemotherapy.

Measures quantified included assessments of each of the PNS noted above and TL [using both a multiplex qPCR assay and a chromosome-specific fluorescence in situ hybridization (FISH) assay].

Results

Variables associated with qPCR mean TLs were age (p = 0.004) and race (T/S ratios higher in Blacks than Whites; p = 0.019). Significant differences (mostly decreases) in chromosome-specific TLs were identified for 32 of the 46 chromosomal arms at the mid-chemo time-point (p = 0.004 to 0.049). Unexpectedly, the sequential administration of doxorubicin [Adriamycin], cyclophosphamide [Cytoxan], and docetaxel [Taxotere] (TAC regimen) was consistently associated with higher TLs, when compared to TLs in women receiving a docetaxel [Taxotere], Carboplatin [Paraplatin], and trastuzumab [Herceptin] [TCH] chemotherapy regimen [association was shown with both the qPCR and FISH assays (p = 0.036)]. Of the PNS, pain was significantly negatively associated with TL (higher pain; shorter telomeres) for a subset of chromosomal arms (5q, 8p, 13p, 20p, 22p, Xp, Xq) (p = 0.014–0.047). Chromosomal TLs were also associated with 7 of the 8 cognitive domains evaluated, with the strongest relationship being noted for chromosome 17 and the visual memory domain (shorter telomeres; lower scores).

Conclusions

We showed that race and age were significantly associated with telomere length in women treated for early stage BC and that acquired telomere alterations differed based on the woman’s treatment regimen. Our study also demonstrated that pain and cognitive domain measures were significantly related to telomere values in this study cohort. Expanding upon the knowledge gained from this longitudinal study could provide insight about the biological cascade of events that contribute to PNS related to BC and/or its treatment.

Supplementary information

The online version contains supplementary material available at 10.1186/s13058-020-01368-6.

Chronic Post-Surgical Pain in the Frail Older Adult

Older adults are the fastest growing segment of the population and surgical procedures in this group increase each year. Chronic post-surgical pain is an important consideration in the older adult as it affects recovery, physical functioning, and overall quality of life. It is increasingly recognized as a public health issue but there is a need to improve our understanding of the disease process as well as the appropriate treatment and prevention. Frailty, delirium, and cognition influence post-operative outcomes in older adults and have been implicated in the development of chronic post-surgical pain. Further research must be conducted to fully understand the role they play in the occurrence of chronic post-surgical pain in the older adult. Additionally, careful attention must be given to the physiologic, cognitive, and comorbidity differences between the older adult and the general population. This is critical for elucidating the proper chronic post-surgical pain treatment and prevention strategies to ensure that the older adult undergoing surgical intervention will have an appropriate and desirable post-operative outcome.

New insights on the arylpiperazinylalkyl pyridazinone ET1 as potent antinociceptive and anti-inflammatory agent

Pyridazine derivatives, such as arylpiperazinylalkyl pyridazinones, display antinociceptive effects to thermal and chemical stimuli. Here, we extended our previous knowledge on the pharmacological profile of 4-amino-6-methyl-2-(3-(4-(4-methylcyclohexa-1,3-dien-1-yl)piperazin-1-yl)propyl)-5-vinylpyridazin-3(2H)-one, here referred as ET1, paving the way for the comprehension of its complete mechanism of action. To this aim, we have evaluated the mouse behavioural responses in several animal models of pain, the effect of ET1 in the murine model of zymosan-induced paw oedema and air-pouch, assessing the cytokines and the cellular phenotype and finally, an in vitro radioligand binding study was performed on a panel of 30 different receptors. In the formalin test, ET1 reduced both neurogenic and inflammatory phase of nociception induced by the aldehyde. Similarly, ET1 strongly reduced paw licking response in the capsaicin test, the abdominal stretching in the writhing test and the carrageenan-induced thermal hyperalgesia. ET1 also evoked a long-lasting reduction of thermal hyperalgesia. Furthermore, ET1 produced a long-lasting anti-inflammatory effect in the zymosan-induced mouse paw oedema and air-pouch through the selective inhibition of inflammatory monocytes recruitment and the modulation of IL-1β, IL-6, TNF-α and MCP-1. Binding experiments confirmed an inhibitory effect on adrenergic α_1A, α_1B and α_2A receptors subtypes and, for the first time, a moderate affinity was observed for the following receptors: histamine H₁, imidazoline I₂, sigma non-opioid intracellular receptor 1 and σ2. These results prompt ET1 as a potent analgesic and anti-inflammatory agent, and support the possibility that it may be suitable for clinical applications in a wide-range of inflammatory-based diseases.

Anti-nociceptive and anti-inflammatory activities of ethanol extract and fractions of Morus mesozygia Stapf (Moraceae) leaves and its underlying mechanisms in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Morus mesozygia Stapf (Moraceae), commonly known as African mulberry, is traditionally used for the treatment of inflammatory disorders such as rheumatism and dermatitis.

AIM

This work aimed to evaluate the anti-nociceptive and anti-inflammatory effects of its ethanol (EEMm) extract, and ethylacetate fraction (EAFMm).

METHODS

The anti-nociceptive and anti-inflammatory effect of ethanol extracts of M. mesozygia (EEMm), and its ethylacetate (EAFMm) and residual aqueous fraction (RAFMm) was evaluated in hotplate, acetic acid and formalin tests and as well in membrane stabilizing assay and carrageenan-induced paw oedema models. Mechanism of anti-inflammation of EAFMm was investigated in the carrageenan-induced air-pouch model.

RESULTS

In the hot plate test of nociception, only the EAFMm showed significant (p < 0.05) anti-nociceptive activity. The extract and fractions significantly reduced number of writhing with EAFMm (400 mg/kg) showing highest inhibition (66.5%) in the acetic acid-induced writhing in mice. EEMm and EAFMm (400 mg/kg) significantly reduced the paw licking time in the early and late phases of the formalin test. The extract and fractions showed good membrane stabilizing activity comparable to indomethacin. EAFMm (100 and 400 mg/kg) showed the highest inhibition of paw oedema (53.4% and 58.1%) in the carrageenan-induced paw oedema model. The EAFMm (100 and 400 mg/kg) reduced exudate volume relative to carrageenan-control (2.64 ± 0.22, 2.08 ± 0.15 vs 3.83 ± 0.18 mL) and neutrophils (8.98 ± 1.36, 8.00 ± 0.22 vs 20.51 ± 1.14) in carrageenan-induced pouch. EAFMm significantly reduced exudate volume, pro-inflammatory cytokines and the expression of COX-2 and NFκB.

CONCLUSION

M. mesozygia leaves demonstrated anti-nociceptive and anti-inflammatory activities by suppressing oxidative stress, pro-inflammatory cytokines, cyclooxygenase-2, and nuclear factor kappa B.

Plasma Concentrations of Select Inflammatory Cytokines Predicts Pain Intensity 48 Hours Post-Shoulder Muscle Injury

OBJECTIVES

The relationship between elevated inflammatory cytokine levels and peak pain intensity following acute musculoskeletal injury has not been fully elucidated in high risk subgroups. Identifying the role that these cytokines have on pain responses may help with developing tailored therapeutic approaches.

METHODS

Data were collected from 54 participants who were vulnerable to a robust pain response and delayed recovery following musculoskeletal injury. Participants completed baseline active and resting pain measurements and a blood draw before an exercised induced shoulder muscle injury. Participants returned at 24 and 48 hours postinjury for follow-up pain measurements and blood draws. Blood plasma was analyzed for interleukin (IL)-1β, IL-6, IL-8, IL-10, and tumor necrosis factor α. Pearson bivariate correlations were performed between cytokines and pain measurements to identify candidate variables for stepwise multiple linear regression predicting pain intensity reports.

RESULTS

Pearson bivariate correlation identified 13/45 correlations between inflammatory cytokines and resting pain intensity and 9/45 between inflammatory cytokines and active pain (P<0.05, r≥0.3 or r≤-0.3). This led to 5 stepwise multiple linear regression models, of which 4 met the statistical criterion (P<0.0167); including IL-10 baseline plasma concentrations predicting active pain (r=0.19) and resting pain (r=0.15) intensity 48 hours postinjury. IL-6 and IL-10 plasma concentrations at 48 hours were respectively associated with active and resting pain at 48 hours.

DISCUSSION

These findings suggest that elevated concentrations of inflammatory cytokines, specifically IL-10 (at baseline and 48 h) and IL-6 (at 48 h), may play a role in heightened pain responses following exercise-induced muscle injury.

Positive and Negative Affect and Salivary Markers of Inflammation Among Young Adults

BACKGROUND

Emerging evidence suggests that higher circulating levels of inflammatory biomarkers in blood are associated with higher negative affect (NA) and lower positive affect (PA). To our knowledge, the unique associations between NA and PA in daily life and salivary biomarkers of inflammation have not been examined. This study examined these associations in young adults.

METHODS

Measures of NA and PA were created from aggregated daily measures of affect (morning and evening ratings averaged across 14 days). We investigated associations between these measures and salivary C-reactive protein (CRP) and interleukin (IL)-6 in a sample of 108 young adults (60% female, mean age = 20.45 ± 1.47), a subset of whom had self-reported chronic back pain (n = 49). CRP and IL-6 were determined from saliva obtained at the end of the daily diary period.

RESULTS

After covarying for age, gender, body mass index, chronic pain status, salivary flow rate, and NA, higher PA was associated with lower salivary CRP (β = - 0.02, 95% CI (- 0.03, - 0.00) sr2 = .06, p = .01) but not IL-6; removing NA from this model did not change results. In a model with the same covariates (and PA), NA was not significantly related to CRP or IL-6. Chronic back pain status and gender did not moderate results.

CONCLUSIONS

Findings suggest that higher PA may be associated with lower salivary CRP in young adults, even after accounting for NA and demographic characteristics. Findings highlight the utility of assessing emotional states in relation to salivary markers of inflammation in future biobehavioral research.

Network between Cytokines, Cortisol and Occupational Stress in Gas and Oilfield Workers

To test whether gas and oil field work is accompanied by stress and altered immune function, the perception of workplace stress, levels of salivary cortisol, plasma levels, and mononuclear cell production of cytokines were examined in 80 healthy workers recruited among a population of operators on gas and oilfields. Specific questionnaires for determining the perception of anxiety, occupational stress, and subjective symptoms were administered. Salivary cortisol and cytokines plasma levels were evaluated by Elisa and to investigate immune function, both spontaneous and PHA- or LPS-induced expression and production of cytokines were assessed by qRT-PCR. Workers showed medium stress levels at work, with growth and increased motivation for work, and based on salivary cortisol concentrations, were divided into two groups of ≤10 ng/mL (n = 31) or >10 ng/mL (n = 49). Statistically significant higher plasma levels of IL-6, while lower TNFα, were detected in workers with cortisol >10 ng/mL. Also, BMI, DL, JD and Job strain were significantly higher in workers with cortisol >10 ng/mL. Thus, even modest variations of cortisol might have a role in the modulation of immune response and worker’s vulnerability to health imbalance.Thus, the evaluation of immune status, in addition to cortisol levels, could be useful to prevent illnesses; exacerbation of pre-existing conditions; morbidity; and consequent absences from work, with economic repercussions.

Gulf War Illness-associated increases in blood levels of interleukin 6 and C-reactive protein: biomarker evidence of inflammation

OBJECTIVE

Gulf War Illness is a chronic multisymptom disorder severely impacting the health and well-being of many Veterans of the 1990-1991 Gulf War. Symptoms that define the disease include pain, fatigue, mood and memory impairments, gastrointestinal problems, lung disorders, and skin rashes. In our previous biomarker study, we discovered Gulf War Illness-associated proinflammatory blood biomarkers. Therefore, we hypothesized that chronic inflammation causes the symptoms that define this disorder. Testing the chronic inflammation hypothesis is the objective of this study.

RESULTS

The biomarker fingerprint of Gulf War Illness is the end-product of a cascade of proinflammatory cytokine signals. In particular, the observed increase in C-reactive protein predicts a corresponding increase in interleukin 6, the cytokine that stimulates hepatocytes to produce C-reactive protein. Therefore, in this study we measured potential upstream cytokine signals in plasma samples from Gulf War Veterans. As predicted, a positive correlation between interleukin 6 and C-reactive protein was observed.

Association Between HIV Symptom Burden and Inflammatory Cytokines: An Analysis by Sex and Menopause Stage

Introduction: There is a growing body of knowledge characterizing the menopause experience in those with HIV. The primary goal of this study was to assess inflammatory cytokine associations with symptoms and sex-specific differences, and the secondary focus was to assess differences among women by menopause status. Materials and Methods: One hundred persons living with HIV (PLWH) (25 men and 75 women recruited by menopause stage) completed a blood draw for hormones and cytokines and study questions on demographics, height and weight, reproductive health status, HIV symptoms, PROMIS-29 measures, and most recent viral load; study visits were synchronized to the early follicular phase in women with regular cycles. Results: In both sexes, the most burdensome HIV symptoms were muscle aches/joint pain, difficulty falling asleep, fatigue, and neuropathy. Three of the five symptoms where burden scores differed by menopause stage were related to pain with highest scores in the premenopause group; the postmenopause group also demonstrated a similar burden for muscle aches/joint pain while scores for men and perimenopause women were lowest. Pain intensity scores on the PROMIS-29 also varied significantly by groups. After controlling for sex, menopause stage and body mass index, significant differences were noted in C-reactive protein (CRP), interleukin (IL)-6, and IL-8 for PLWH who reported muscle aches/joint pain. Conclusions: Our findings suggest enhanced burden for HIV-related symptoms in women in the early follicular phase, possibly owing to menstruation. This supports the need for more targeted investigations in younger cycling women with HIV at multiple phases across the menstrual cycle. Muscle aches/pain are strongly associated with decreased CRP and IL-8 levels and increased IL-6 levels suggesting the need for further investigation of the biological pathways contributing to pain in PLWH. Finally, there is evidence to support that in PLWH, systemic inflammation is heightened above recommended clinical guidelines even when viral load is undetectable supporting the need for further study of the effects of persistent elevated inflammation on health outcomes.

Differences in the miRNA signatures of chronic musculoskeletal pain patients from neuropathic or nociceptive origins

BACKGROUND

The quality of life for millions of people worldwide is affected by chronic pain. In addition to the effect of chronic pain on well-being, chronic pain has also been associated with poor health conditions and increased mortality. Due to its multifactorial origin, the classification of pain types remains challenging. MicroRNAs (miRNA) are small molecules that regulate gene expression. They are released into the bloodstream in a stable manner under normal and pathological conditions and have been described as potential biomarkers. In the present study, we aimed to investigate whether pain may induce an aberrant, specific dysregulation of miRNA expression, depending on the origin of the pain.

METHODS AND FINDINGS

To do so, we measured the expression changes of 184 circulating miRNAs (c-miRNAs) in the plasma samples of patients with different origins of chronic musculoskeletal pain. After statistical analyses, we identified seven c-miRNA candidates that were differentially expressed depending on the nociceptive or neuropathic origin of the pain. We then developed a two c-miRNA signature (hsa-miR-320a and hsa-miR-98-5p) that was able to correctly classify the pain type of 70% of the patients from the validation set.

CONCLUSIONS

In conclusion, circulating miRNAs are promising biomarkers to identify and characterize the chronic pain type and to further improve its clinical management.

Protein Cytokines, Cytokine Gene Polymorphisms, and Potential Acute Coronary Syndrome Symptoms

The purpose of this study was to determine whether relationships exist among protein cytokines, cytokine gene polymorphisms, and symptoms of potential acute coronary syndrome (ACS). Participants included 438 patients presenting to the emergency department (ED) whose symptoms triggered a cardiac evaluation (206 ruled in and 232 ruled out for ACS). Presence or absence of 13 symptoms was recorded upon arrival. Levels of tumor necrosis factor α (TNF-α), interleukin (IL)-6, and IL-18 were measured for all patients. A pilot analysis of 85 patients (ACS = 49; non-ACS = 36) genotyped eight single-nucleotide polymorphisms (SNPs; four TNF and four IL6 SNPs). Logistic regression models were tested to determine whether cytokines or SNPs predicted symptoms. Increased levels of TNF-α and IL-6 were associated with a decreased likelihood of chest discomfort for all patients. Increased levels of IL-6 were associated with a lower likelihood of chest discomfort and chest pressure for ACS patients, and an increased likelihood of shoulder and upper back pain for non-ACS patients. Elevated IL-18 was associated with an increased likelihood of sweating in patients with ACS. Of the four TNF SNPs, three were associated with shortness of breath, lightheadedness, unusual fatigue, and arm pain. In all, protein cytokines and TNF polymorphisms were associated with 11 of 13 symptoms assessed. Future studies are needed to determine the predictive ability of cytokines and related SNPs for a diagnosis of ACS or to determine whether biomarkers can identify patients with specific symptom clusters.

Genetic Variants and the Cortisol Response in Children: An Exploratory Study

OBJECTIVE

We examined genomic variation potentially associated with the cortisol stress response in children having a painful medical procedure.

DESIGN

Children 4-10 years old having a peripheral intravenous line inserted provided saliva samples for evaluation of the cortisol response as a biological measure of distress: two on the day of the procedure and two at home on a nonstressful day for comparison values. Children and biological parents also provided samples for genotyping of variants with known or suspected association with the cortisol stress response. Analysis included child-only association and family-based transmission disequilibrium tests (TDTs).

RESULTS

Genotype and phenotype data on the cortisol stress response were available from 326 children for child-only association analyses and 376 complete family trios for TDTs. Children were 50% female, an average of 7.5 years old, and mostly (83%) White/non-Hispanic. We identified four single-nucleotide polymorphisms (SNPs) potentially associated with the cortisol stress response: rs1176744 ( HTR3B), rs10062367 ( CRHBP), rs634479 ( OPRM1), and rs8030107 ( NTRK3). Family-based analysis identified a two-SNP haplotype in HTR1B suggestive for association with the cortisol response (rs6296, rs11568817). Allelic TDTs identified rs7897947 ( NFKB2) as potentially related to cortisol response.

CONCLUSIONS

Findings provide preliminary evidence for genes potentially important in cortisol response to an acute stressor in children in the serotonin, dopamine, and brain-derived neurotrophic factor pathways, the hypothalamic-pituitary-adrenal axis, and the inflammatory response. Combined with analyses of related phenotypes and clinical data, these results could help identify patients at increased risk of adverse responses to painful medical procedures who might benefit from tailored interventions.

Sex differences in how inflammation affects behavior: What we can learn from experimental inflammatory models in humans

Human models demonstrate that experimental activation of the innate immune system has profound effects on brain activation and behavior, inducing fatigue, worsened mood and pain sensitivity. It has been proposed that inflammation is a mechanism involved in the etiology and maintenance of depression, chronic pain and long-term fatigue. These diseases show a strong female overrepresentation, suggesting that a better understanding of sex differences in how inflammation drives behavior could help the development of individualized treatment interventions. For this purpose, we here review sex differences in studies using experimental inflammatory models to investigate changes in brain activity and behavior. We suggest a model in which inflammation accentuates sex differences in brain networks and pre-existing vulnerability factors. This effect could render women more vulnerable to the detrimental effects of immune-to-brain communication over time. We call for systematic and large scale investigations of vulnerability factors for women in the behavioral response to inflammation.

Biopsychosocial Assessment of Pain with Thermal Imaging of Emotional Facial Expression in Breast Cancer Survivors

Background: Recent research has evaluated psychological and biological characteristics associated with pain in survivors of breast cancer (BC). Few studies consider their relationship with inflammatory activity. Voluntary facial expressions modify the autonomic activity and this may be useful in the hospital environment for clinical biopsychosocial assessment of pain. Methods: This research compared a BC survivors group under integral treatment (Oncology, Psychology, Nutrition) with a control group to assess the intensity of pain, behavioral interference, anxiety, depression, temperament-expression, anger control, social isolation, emotional regulation, and alexithymia and inflammatory activity, with salivary interleukin 6 (IL-6). Then, a psychophysiological evaluation through repeated measures of facial infrared thermal imaging (IRT) and hands in baseline—positive facial expression (joy)—negative facial expression (pain)—relaxation (diaphragmatic breathing). Results: The results showed changes in the IRT (p < 0.05) during the execution of facial expressions in the chin, perinasal, periorbital, frontal, nose, and fingers areas in both groups. No differences were found in the IL-6 level among the aforementioned groups, but an association with baseline nasal temperature (p < 0.001) was observable. The BC group had higher alexithymia score (p < 0.01) but lower social isolation (p < 0.05), in comparison to the control group. Conclusions: In the low- and medium-concentration groups of IL-6, the psychophysiological intervention proposed in this study has a greater effect than on the high concentration group of IL-6. This will be considered in the design of psychological and psychosocial interventions for the treatment of pain.

Biomarkers as Common Data Elements for Symptom and Self-Management Science

PURPOSE

Biomarkers as common data elements (CDEs) are important for the characterization of biobehavioral symptoms given that once a biologic moderator or mediator is identified, biologically based strategies can be investigated for treatment efforts. Just as a symptom inventory reflects a symptom experience, a biomarker is an indicator of the symptom, though not the symptom per se. The purposes of this position paper are to (a) identify a "minimum set" of biomarkers for consideration as CDEs in symptom and self-management science, specifically biochemical biomarkers; (b) evaluate the benefits and limitations of such a limited array of biomarkers with implications for symptom science; (c) propose a strategy for the collection of the endorsed minimum set of biologic samples to be employed as CDEs for symptom science; and (d) conceptualize this minimum set of biomarkers consistent with National Institute of Nursing Research (NINR) symptoms of fatigue, depression, cognition, pain, and sleep disturbance.

DESIGN AND METHODS

From May 2016 through January 2017, a working group consisting of a subset of the Directors of the NINR Centers of Excellence funded by P20 or P30 mechanisms and NINR staff met bimonthly via telephone to develop this position paper suggesting the addition of biomarkers as CDEs. The full group of Directors reviewed drafts, provided critiques and suggestions, recommended the minimum set of biomarkers, and approved the completed document. Best practices for selecting, identifying, and using biological CDEs as well as challenges to the use of biological CDEs for symptom and self-management science are described. Current platforms for sample outcome sharing are presented. Finally, biological CDEs for symptom and self-management science are proposed along with implications for future research and use of CDEs in these areas.

FINDINGS

The recommended minimum set of biomarker CDEs include pro- and anti-inflammatory cytokines, a hypothalamic-pituitary-adrenal axis marker, cortisol, the neuropeptide brain-derived neurotrophic factor, and DNA polymorphisms.

CONCLUSIONS

It is anticipated that this minimum set of biomarker CDEs will be refined as knowledge regarding biologic mechanisms underlying symptom and self-management science further develop. The incorporation of biological CDEs may provide insights into mechanisms of symptoms, effectiveness of proposed interventions, and applicability of chosen theoretical frameworks. Similarly, as for the previously suggested NINR CDEs for behavioral symptoms and self-management of chronic conditions, biological CDEs offer the potential for collaborative efforts that will strengthen symptom and self-management science.

CLINICAL RELEVANCE

The use of biomarker CDEs in biobehavioral symptoms research will facilitate the reproducibility and generalizability of research findings and benefit symptom and self-management science.

Epidurals in Pancreatic Resection Outcomes (E-PRO) study: protocol for a randomised controlled trial

INTRODUCTION

Epidural analgesia provides an important synergistic method of pain control. In addition to reducing perioperative opioid consumption, the deliverance of analgesia into the epidural space, effectively creating a sympathetic blockade, has a multitude of additional potential benefits, from decreasing the incidence of postoperative delirium to reducing the development of persistent postsurgical pain (PPSP). Prior studies have also identified a correlation between the use of epidural analgesia and improved oncological outcomes and survival. The aim of this study is to evaluate the effect of epidural analgesia in pancreatic operations on immediate postoperative outcomes, the development of PPSP and oncological outcomes in a prospective, single-blind, randomised controlled trial.

METHODS

The Epidurals in Pancreatic Resection Outcomes (E-PRO) study is a prospective, single-centre, randomised controlled trial. 150 patients undergoing either pancreaticoduodenectomy or distal pancreatectomy will be randomised to receive an epidural bupivacaine infusion following anaesthetic induction followed by continued epidural bupivacaine infusion postoperatively in addition to the institutional standardised pain regimen of hydromorphone patient-controlled analgesia (PCA), acetaminophen and ketorolac (intervention group) or no epidural infusion and only the standardised postoperative pain regimen (control group). The primary outcome was the postoperative opioid consumption, measured in morphine or morphine-equivalents. Secondary outcomes include patient-reported postoperative pain numerical rating scores, trend and relative ratios of serum inflammatory markers (interleukin (IL)-1β, IL-6, tumour necrosis factor-α, IL-10), occurrence of postoperative delirium, development of PPSP as determined by quantitative sensory testing, and disease-free and overall survival.

ETHICS AND DISSEMINATION

The E-PRO trial has been approved by the institutional review board. Recruitment began in May 2016 and will continue until the end of May 2018. Dissemination plans include presentations at scientific conferences and scientific publications.

TRIAL REGISTRATION NUMBER

NCT02681796.

Antinociceptive and Antibacterial Properties of Anthocyanins and Flavonols from Fruits of Black and Non-Black Mulberries

Anthocyanins and flavones are important pigments responsible for the coloration of fruits. Mulberry fruit is rich in anthocyanins and flavonols, which have multiple uses in traditional Chinese medicine. The antinociceptive and antibacterial activities of total flavonoids (TF) from black mulberry (MnTF, TF of Morus nigra) and non-black mulberry (MmTF, TF of Morus mongolica; and MazTF, TF of Morus alba 'Zhenzhubai') fruits were studied. MnTF was rich in anthocyanins (11.3 mg/g) and flavonols (0.7 mg/g) identified by ultra-performance liquid chromatography-tunable ultraviolet/mass single-quadrupole detection (UPLC-TUV/QDa). Comparatively, MmTF and MazTF had low flavonol contents and MazTF had no anthocyanins. MnTF showed significantly higher antinociceptive and antibacterial activities toward Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus than MmTF and MazTF. MnTF inhibited the expression of interleukin 6 (IL-6), inducible nitric oxide synthase (iNOS), phospho-p65 (p-p65) and phospho-IκBα (p-IκBα), and increased interleukin 10 (IL-10). Additionally, mice tests showed that cyanidin-3-O-glucoside (C3G), rutin (Ru) and isoquercetin (IQ) were the main active ingredients in the antinociceptive process. Stronger antinociceptive effect of MnTF was correlated with its high content of anthocyanins and flavonols and its inhibitory effects on proinflammatory cytokines, iNOS and nuclear factor-κB (NF-κB) pathway-related proteins.

Characteristics of Tables for Disseminating Biobehavioral Results

BACKGROUND

To report the complexity and richness of study variables within biological nursing research, authors often use tables; however, the ease with which consumers understand, synthesize, evaluate, and build upon findings depends partly upon table design.

OBJECTIVES

To assess and compare table characteristics within research and review articles published in Biological Research for Nursing and Nursing Research.

METHOD

A total of 10 elements in tables from 48 biobehavioral or biological research or review articles were analyzed. To test six hypotheses, a two-level hierarchical linear model was used for each of the continuous table elements, and a two-level hierarchical generalized linear model was used for each of the categorical table elements. Additionally, the inclusion of probability values in statistical tables was examined.

RESULTS

The mean number of tables per article was 3. Tables in research articles were more likely to contain quantitative content, while tables in review articles were more likely to contain both quantitative and qualitative content. Tables in research articles had a greater number of rows, columns, and column-heading levels than tables in review articles. More than one half of statistical tables in research articles had a separate probability column or had probability values within the table, whereas approximately one fourth had probability notes.

CONCLUSIONS

Authors and journal editorial staff may be generating tables that better depict biobehavioral content than those identified in specific style guidelines. However, authors and journal editorial staff may want to consider table design in terms of audience, including alternative visual displays.

Relationship between Sleep, Pain and Inflammatory Markers in Patients with Rheumatoid Arthritis

Introduction: Rheumatoid Arthritis (RA) is known as a progressive chronic auto-immune disease. Measurement of inflammatory markers are applied for follow up the activity of disease. So determining factors that effects these markers such as sleep and pain can help to prevent the severity of disease. The aim of study was to determine the relationship between sleep disorders, pain and inflammatory markers in patients with RA.

Methods: Participants included 210 patients with RA referred to educational medical clinics of Imam Reza and Sina in Tabriz selected by convenience sampling. They were assessed by Sleep Disorders Questionnaire (SDQ) and Epworth Sleepiness Scale (ESS). Visual Analog Scale (VAS) also applied for pain measurement. Data were analyzed using SPSS ver.13 by descriptive and inferential statistics.

Results: Most of participants (74%) were female, the mean age of participants was 48.41 years. The mean (SD) of sleepiness was 13.14 (5.6) and pain 6.09 (2.14). Significant relationship obtained between sleep disorders and pain. As well as sleep problems had significant relation with CRP. Also pain had significant correlation with inflammatory markers.

Conclusion: Sleep pattern in RA appears to be disrupted by pain. Pain severity and sleep problems can predict increasing inflammatory markers that can be a clues of intensity of disease. So relieving pain and improved sleep can decrease the intensity of disease.

Alterations in the inflammatory cytokines and brain-derived neurotrophic factor contribute to depression-like phenotype after spared nerve injury: improvement by ketamine

Although pain is frequently accompanied with depression, little is known about the risk factors contributing to individual differences to the comorbidity of pain and depression. In this study, we examined whether cytokines and brain-derived neurotrophic factor (BDNF) might contribute to the individual differences in the development of neuropathic pain-induced depression. Rats were randomly subjected to spared nerved ligation (SNI) or sham surgery. The SNI rats were divided into two groups by the data from depression-related behavioral tests. Rats with depression-like phenotype displayed higher levels of pro-inflammatory cytokines (e.g., interleukin (IL)-1β, IL-6) as well as imbalance of pro/anti-inflammatory cytokines compared with rats without depression-like phenotype and sham-operated rats. Levels of BDNF in the prefrontal cortex of rats with depression-like phenotype were lower than those of rats without depression-like phenotype and sham-operated rats. A single dose of ketamine ameliorated depression-like behaviors in the rats with depression-like phenotype. Interestingly, higher serum levels of IL-1β and IL-6 in the rat with depression-like phenotype were normalized after a single dose of ketamine. These findings suggest that alterations in the inflammatory cytokines and BDNF might contribute to neuropathic pain-induced depression, and that serum cytokines may be predictable biomarkers for ketamine’s antidepressant actions.

Relationship of Genetic Variants With Procedural Pain, Anxiety, and Distress in Children

OBJECTIVE

This study used a candidate gene approach to examine genomic variation associated with pain, anxiety, and distress in children undergoing a medical procedure.

STUDY DESIGN

Children aged 4-10 years having an IV catheter insertion were recruited from three Midwestern children's hospitals. Self-report measures of pain, anxiety, and distress were obtained as well as an observed measure of distress. Samples were collected from children and biological parents for analysis of genomic variation. Genotyped variants had known or suspected association with phenotypes of interest. Analyses included child-only association and family-based transmission disequilibrium tests.

RESULTS

Genotype and phenotype data were available from 828 children and 376 family trios. Children were 50% male, had a mean age of 7.2 years, and were 84% White/non-Hispanic. In family-based analysis, one single-nucleotide polymorphism (SNP; rs1143629, interleukin ( IL1B) 1β) was associated with observed child distress at Bonferroni-corrected levels of significance ( p = .00013), while two approached significance for association with high state anxiety (rs6330 Nerve Growth Factor, Beta Subunit, [ NGFB]) and high trait anxiety (rs6265 brain-derived neurotrophic factor [ BDNF]). In the child-only analysis, multiple SNPs showed nominal evidence of relationships with phenotypes of interest. rs6265 BDNF and rs2941026 cholecystokinin B receptor had possible relationships with trait anxiety in child-only and family-based analyses.

CONCLUSIONS

Exploring genomic variation furthers our understanding of pain, anxiety, and distress and facilitates genomic screening to identify children at high risk of procedural pain, anxiety, and distress. Combined with clinical observations and knowledge, such explorations could help guide tailoring of interventions to limit procedure-related distress and identify genes and pathways of interest for future genotype-phenotype studies.

Lifetime Modulation of the Pain System via Neuroimmune and Neuroendocrine Interactions

Chronic pain is a debilitating condition that still is challenging both clinicians and researchers. Despite intense research, it is still not clear why some individuals develop chronic pain while others do not or how to heal this disease. In this review, we argue for a multisystem approach to understand chronic pain. Pain is not only to be viewed simply as a result of aberrant neuronal activity but also as a result of adverse early-life experiences that impact an individual's endocrine, immune, and nervous systems and changes which in turn program the pain system. First, we give an overview of the ontogeny of the central nervous system, endocrine, and immune systems and their windows of vulnerability. Thereafter, we summarize human and animal findings from our laboratories and others that point to an important role of the endocrine and immune systems in modulating pain sensitivity. Taking "early-life history" into account, together with the past and current immunological and endocrine status of chronic pain patients, is a necessary step to understand chronic pain pathophysiology and assist clinicians in tailoring the best therapeutic approach.

Role of Inflammation in Human Fatigue: Relevance of Multidimensional Assessments and Potential Neuronal Mechanisms

Fatigue is a highly disabling symptom in various medical conditions. While inflammation has been suggested as a potential contributor to the development of fatigue, underlying mechanisms remain poorly understood. In this review, we propose that a better assessment of central fatigue, taking into account its multidimensional features, could help elucidate the role and mechanisms of inflammation in fatigue development. A description of the features of central fatigue is provided, and the current evidence describing the association between inflammation and fatigue in various medical conditions is reviewed. Additionally, the effect of inflammation on specific neuronal processes that may be involved in distinct fatigue dimensions is described. We suggest that the multidimensional aspects of fatigue should be assessed in future studies of inflammation-induced fatigue and that this would benefit the development of effective therapeutic interventions.

Why sickness hurts: A central mechanism for pain induced by peripheral inflammation

Low-grade systemic inflammation has been implicated in chronic pain, as well as in comorbid diseases like depression and fatigue. We have previously shown that women's pain perception and regulation is more affected by systemic inflammation than that of men. Here we investigated the neural substrates underlying these effects using an fMRI paradigm previously employed in a clinical population. Fifty-one participants (29 women) were injected with 0.6ng/kg lipopolysaccharide (LPS) or saline to induce a peripheral inflammatory response. The subjects were then tested with a pressure pain fMRI paradigm designed to capture descending pain inhibitory activity 2h after injection, and blood was sampled for cytokine analysis. The subjects injected with LPS became more pain sensitive compared to the placebo group, and the heightened pain sensitivity was paralleled by decreased activity in the ventrolateral prefrontal cortex and the rostral anterior cingulate cortex (rACC) compared to placebo; areas involved in descending pain regulation. The LPS group also had higher activity in the anterior insular cortex, an area underpinning affective and interoceptive pain processing. Women displayed overall less pain-evoked rACC activity compared to men, which may have rendered women less resilient to immune provocation, possibly explaining sex differences in LPS-induced pain sensitivity. Our findings elucidate the pain-related brain circuits affected by experimental peripheral inflammation, strengthening the theoretical link between systemic inflammation and weakened pain regulation in chronic pain disorders. The results further suggest a possible mechanism underlying the female predominance in many chronic pain disorders.

A Multiplex Protein Panel Applied to Cerebrospinal Fluid Reveals Three New Biomarker Candidates in ALS but None in Neuropathic Pain Patients

The objective of this study was to develop and apply a novel multiplex panel of solid-phase proximity ligation assays (SP-PLA) requiring only 20 μL of samples, as a tool for discovering protein biomarkers for neurological disease and treatment thereof in cerebrospinal fluid (CSF). We applied the SP-PLA to samples from two sets of patients with poorly understood nervous system pathologies amyotrophic lateral sclerosis (ALS) and neuropathic pain, where patients were treated with spinal cord stimulation (SCS). Forty-seven inflammatory and neurotrophic proteins were measured in samples from 20 ALS patients and 15 neuropathic pain patients, and compared to normal concentrations in CSF from control individuals. Nineteen of the 47 proteins were detectable in more than 95% of the 72 controls. None of the 21 proteins detectable in CSF from neuropathic pain patients were significantly altered by SCS. The levels of the three proteins, follistatin, interleukin-1 alpha, and kallikrein-5 were all significantly reduced in the ALS group compared to age-matched controls. These results demonstrate the utility of purpose designed multiplex SP-PLA panels in CSF biomarker research for understanding neuropathological and neurotherapeutic mechanisms. The protein changes found in the CSF of ALS patients may be of diagnostic interest.

A novel coumarin, (+)-3'-angeloxyloxy-4'-keto-3',4'-dihydroseselin, isolated from Bupleurum malconense (Chaihu) inhibited NF-κB activity

Background

This study aims to identify the major anti-inflammatory components in the petroleum ether extract of Bupleurummalconense (Chaihu), by bioassay-guided fractionation, and to investigate the anti-inflammatory mechanisms of active components in lipopolysaccharide (LPS)-stimulated murine macrophage RAW-Blue cells.

Methods

A QUANTI-Blue assay was used to guide fractionation of B.malconense root extract. The petroleum ether extract which exerted significant secreted embryonic alkaline phosphatase (SEAP) inhibition effect was purified by silica gel column chromatography and assisted with reverse phase HPLC. The major bioactive compound which significantly inhibited SEAP activity was obtained and its anti-inflammatory effects in LPS-induced RAW-Blue cells were measured by the overproduction of NO (Griess method), gene expression of Il-1β, Tnf-α and iNos (real-time PCR). In parallel, protein expressions of COX-2, iNOS and IκB-α were determined by western blot.

Results

In bioassay-guided fractionation using LPS-stimulated mouse macrophage RAW-Blue cells, (+)-3′-angeloxyloxy-4′-keto-3′,4′-dihydroseselin (Pd-Ib) was identified by MS and NMR spectral analyses. Pd-Ib (5, 10, 20 μg/mL) suppressed the gene expression of Il-1β (P < 0.0001, P < 0.0001, P < 0.0001 for three respective concentrations), Tnf-α (P = 0.006, P = 0.001, P < 0.0001 for three respective concentrations) and iNos (P = 0.009, P < 0.0001, P < 0.0001 for three respective concentrations) in LPS-stimulated macrophages. The production of cyclooxygenase-2 (P = 0.019, P = 0.002, P < 0.0001), iNOS (P < 0.0001, P < 0.0001, P < 0.0001 for three respective concentrations) and NO (P < 0.0001, P < 0.0001, P < 0.0001 for three respective concentrations) significantly decreased when macrophages were treated with Pd-Ib (5, 10, 20 μg/mL) in the presence of LPS. Pd-Ib (5, 10, 20 μg/mL) suppressed the nuclear activation of NF-κB while it up-regulated the IκB-α level (P = 0.028, P = 0.013, P = 0.005 for three respective concentrations) in LPS-stimulated macrophages.

Conclusions

Pd-Ib isolated from B.malconense suppressed LPS-induced inflammatory responses in macrophages by inhibiting NF-κB activity and reducing the expression of iNOS, COX-2 as well as pro-inflammatory cytokines.

Electronic supplementary material

The online version of this article (doi:10.1186/s13020-016-0077-x) contains supplementary material, which is available to authorized users.

Building a Biopsychosocial Conceptual Framework to Explore Pressure Ulcer Pain for Hospitalized Patients

Although pressure ulcers are a prevalent condition, pain associated with pressure ulcers is not fully understood. Indeed, previous studies do not shed light on the association between pressure ulcer stages and the experience of pain. Especially, pain characteristics of suspected deep tissue injury, which is a new category that was recently added by the National Pressure Ulcer Advisory Panel, are yet unknown. This is concerning because the incidence of pressure ulcers in hospitalized patients has increased exponentially over the last two decades, and health care providers are struggling to ensure providing adequate care. Thus, in order to facilitate the development of effective interventions, this paper presents a conceptual framework to explore pressure ulcer pain in hospitalized patients. The concepts were derived from a biopsychosocial model of pain, and the relationships among each concept were identified through a literature review. Major propositions are presented based on the proposed conceptual framework, which integrates previous research on pressure ulcer pain, to ultimately improve understanding of pain in hospitalized patients with pressure ulcers.

Plasma pro-inflammatory markers in chronic neuropathic pain: A multivariate, comparative, cross-sectional pilot study

BACKGROUND

Caused by a lesion or disease of the somatosensory system, neuropathic pain is notoriously difficult to treat with conventional analgesics. It has been suggested that inflammatory cytokines play a role in the development and maintenance of neuropathic pain. But human studies of these substances are relatively few and partly contradictory.

OBJECTIVES

To simultaneously investigate the plasma levels of chemokine interleukin 8 (IL-8) and the cytokines IL-6, IL-1β, and Granulocyte macrophage colony-stimulating factor (GM-CSF) in patients with peripheral neuropathic pain (most of whom due to failed back surgery syndrome) (n=14) compared to controls (n=17).

RESULTS

IL-6 was significantly higher in patients than in controls (0.92±0.12pg/ml vs. 0.57±0.08pg/ml, p=0.012). IL-1β, IL-8, and GM-CSF levels did not differ between the two groups. A multivariate analysis showed a tendency for patients also to have higher GM-CSF plasma levels than controls.

CONCLUSIONS

This study found an increased level of IL-6 in plasma in patients with neuropathic pain, but not for the other pro-inflammatory substances investigated. There are several possible confounders not registered or controlled for in this and other studies of neuropathic pain.

IMPLICATIONS

Larger studies that take several possible confounders into consideration are needed to further investigate the levels of plasma cytokines in different pain conditions.