The biochemical origin of pain--proposing a new law of pain: the origin of all pain is inflammation and the inflammatory response. Part 1 of 3--a unifying law of pain

Genome-wide association studies with experimental validation identify a protective role for B lymphocytes against chronic post-surgical pain

BACKGROUND

Chronic post-surgical pain (CPSP) significantly impacts patients' recovery and quality of life. Although environmental risk factors are well-established, genetic risk remains less understood.

METHODS

A meta-analysis of genome-wide association studies followed by partitioned heritability was performed on 1350 individuals across five surgery types: hysterectomy, mastectomy, abdominal, hernia, and knee. In subsequent animal studies, withdrawal thresholds to evoked mechanical stimulation were measured in Rag1 null mutant and wild-type mice after plantar incision and laparotomy. Cell sorting by flow cytometry tracked recruitment of immune cell types.

RESULTS

We discovered 77 genome-wide significant single-nucleotide polymorphism (SNP) hits, distributed among 24 loci and 244 genes. Meta-analysis of all cohorts estimated a SNP-based narrow-sense heritability for CPSP at ∼39%, indicating a substantial genetic contribution. Partitioned heritability analysis across a wide variety of tissues revealed enrichment of heritability in immune system-related genes, particularly those associated with B and T cells. Rag1 null mutant mice lacking both T and B cells exhibited exacerbated and prolonged allodynia up to 42 days after surgery, which was rescued by B-cell transfer. Recruitment patterns of B cells but not T cells differed significantly during the first 7 days after injury in the footpad, lymph nodes, and dorsal root ganglia.

CONCLUSIONS

These findings suggest a key protective role for the adaptive immune system in the development of chronic post-surgical pain.

Pain Management Strategies in Osteoarthritis

Pain is the major symptom of osteoarthritis (OA) and is an important factor in strategies to manage this disease. However, the current standard of care does not provide satisfactory pain relief for many patients. The pathophysiology of OA is complex, and its presentation as a clinical syndrome is associated with the pathologies of multiple joint tissues. Treatment options are generally classified as pharmacologic, nonpharmacologic, surgical, and complementary and/or alternative, typically used in combination to achieve optimal results. The goals of treatment are the alleviation of symptoms and improvement in functional status. Several studies are exploring various directions for OA pain management, including tissue regeneration techniques, personalized medicine, and targeted drug therapies. The aim of the present narrative review is to extensively describe all the treatments available in the current practice, further describing the most important innovative therapies. Advancements in understanding the molecular and genetic aspects of osteoarthritis may lead to more effective and tailored treatment approaches in the future.

Effects of exercise-based interventions on inflammatory markers in patients with fibromyalgia: A systematic review and meta-analysis

OBJECTIVES

The aim of the present review was (1) to determine the effects of exercise based-interventions (EBIs) on pro-inflammatory and anti-inflammatory biomarkers in patients with fibromyalgia (FM), and (2) to determine the most effective type (acute or maintained) and modality (aerobic, resistance, etc.).

METHODS

A systematic search was conducted in various electronic databases to identify all the relevant studies: Medline (PubMed), PEDro, EBSCO and Google Scholar. Clinical trials assessing the effects of EBIs in patients with FM were selected. Methodological quality was evaluated by two independent investigators using the Cochrane Risk of Bias Tool. Qualitative analysis was based on the classification of the results into levels of evidence according to GRADE.

RESULTS

Eleven studies were included. The meta-analysis showed a statistically significant decrease in proinflammatory biomarkers by EBIs with a large clinical effect in 19 comparisons (SMD: 1.74; 95 % CI: 0.85-2.62; p < 0.05), especially for IL8. The certainty of the evidence was low. The meta-analysis showed no statistically significant increase in anti-inflammatory biomarkers (IL10) by EBIs in 6 comparisons and very low certainty of evidence. Evidence was found for acute and maintained effects of exercise, with aerobic and aquatic exercise modalities showing better improvements than resistance exercise.

CONCLUSIONS

EBIs are effective in inducing an immunomodulatory response in FM, characterized by decreased pro-inflammatory signaling. However, there was no evidence of an increase in anti-inflammatory biomarkers. These results should be interpreted with caution due to low certainty of evidence.

Prolonged continuous wound infusion of local anesthetic and steroid after major abdominal surgery to reduce opioid consumption: a randomized, double-blind trial

BACKGROUND

Continuous wound infusion (CWI) is effective for post-operative pain management, but the effect of prolonged infusions and the use of steroids in the infused mixture have never been addressed. We investigate the effect of prolonged CWI with ropivacaine 0.2% (R) over seven days and methylprednisolone (Mp) 1 mg/kg infused in the wound in the first 24 hours.

METHODS

This is a randomized, double blind, phase III trial (RCT) in major abdominal surgery with laparotomy. After a 24-hours pre-peritoneal CWI of R-Mp, patients were randomized to receive either R-Mp or placebo for the next 24 hours. Then, patient-controlled CWI with only ropivacaine 0.2% or placebo (according to the randomization group) was planned between 48 hours and seven days after surgery. Morphine equivalents at seven days were analyzed, together with any catheter- or drug-related side effect and PPSP at 3 months.

RESULTS

We enrolled 120 patients (63 in the CWI group, 57 in the placebo group). Prolonged CWI did not reduce opioid consumption in the first seven postoperative days (P=0.08). CWI was associated with reduced consumption of non-opioid analgesics (P=0.03). Most of the patients continued to require bolus in the surgical wound beyond 48 hours. PPSP prevalence was not different between groups.

CONCLUSIONS

Prolonged infusion with R-Mp is safe and effective but did not reduce opioid consumption in the seven days after surgery or PPSP prevalence.

Genome-wide association study suggests a critical contribution of the adaptive immune system to chronic post-surgical pain

Chronic post-surgical pain affects a large proportion of people undergoing surgery, delaying recovery time and worsening quality of life. Although many environmental variables have been established as risk factors, less is known about genetic risk. To uncover genetic risk factors we performed genome-wide association studies in post-surgical cohorts of five surgery types- hysterectomy, mastectomy, abdominal, hernia, and knee- totaling 1350 individuals. Genetic associations between post-surgical chronic pain levels on a numeric rating scale (NRS) and additive genetic effects at common SNPs were evaluated. We observed genome-wide significant hits in almost all cohorts that displayed significance at the SNP, gene, and pathway levels. The cohorts were then combined via a GWAS meta-analysis framework for further analyses. Using partitioned heritability, we found that loci at genes specifically expressed in the immune system carried enriched heritability, especially genes related to B and T cells. The relevance of B cells in particular was then demonstrated in mouse postoperative pain assays. Taken altogether, our results suggest a role for the adaptive immune system in chronic post-surgical pain.

Educational Curriculum for Peripheral Nerve Stimulation Developed by the North American Neuromodulation Society

BACKGROUND

Peripheral nerve stimulation (PNS) is an effective neuromodulation therapy for chronic neuropathic and nociceptive pain. Although the total number of PNS implantations has increased over the last decade, no curriculum exists to guide training and learning of this therapy. The goal of the North American Neuromodulation Society (NANS) education committee is to develop a series of competency-based curriculums for neuromodulation therapies. The PNS curriculum is the latest part of such series, following the curriculums for spinal cord stimulation and intrathecal drug delivery system.

MATERIALS AND METHODS

A multidisciplinary task force (anesthesiology, physical medicine and rehabilitation, neurosurgery, preventive medicine and public health, and neurology) was created by the educational committee of NANS to develop a PNS curriculum in accordance with the Accreditation Council for Graduate Medical Education (ACGME) milestones. The curriculum was created based on the best available evidence and expert knowledge (from our task force members) of available PNS systems. The final PNS curriculum was approved by the NANS board.

RESULTS

A PNS curriculum was developed by the task force. Milestones included professionalism, practice-based learning, interpersonal communication, medical knowledge, systems-based practice, procedural skills, and patient care. Each milestone was defined into three categories: early learner, advanced learner, and practitioner.

CONCLUSIONS

This manuscript provides a PNS training curriculum developed by a multidisciplinary task force of the NANS educational committee in accordance with the milestones described by ACGME for basic learners, advanced learners, and practitioners. This curriculum will help provide a structured training and evaluation process for obtaining proficiency in PNS treatment(s).

Liquid Biopsy-Based Biomarkers of Inflammatory Nociception Identified in Male Rats

Physicians are challenged in treating pain patients due to the lack of quantifiable, objective methods of measuring pain in the clinic; pain sensation is multifaceted and subjective to each individual. There is a critical need for point-of-care quantification of accessible biomarkers to provide objective analyses beyond the subjective pain scales currently employed in clinical care settings. In the present study, we employed an animal model to test the hypothesis that circulating regulators of the inflammatory response directly associate with an objective behavioral response to inflammatory pain. Upon induction of localized paw inflammation, we measured the systemic protein expression of cytokines, and activity levels of matrix metalloproteinases (MMPs) that are known to participate in the inflammatory response at the site of injury and investigated their relationship to the behavioral response across a 24 h period. Intraplantar injection with 1% λ-carrageenan induced a significant increase in paw thickness across this timespan with maximal effects observed at the 8 h timepoint when locomotor activity was also impaired. Expression of the chemokines C-X-C motif chemokine ligand 1 (CXCL1) and C-C motif chemokine ligand 2 (CCL2) positively correlated with paw inflammation and negatively correlated with locomotor activity at 8 h. The ratio of MMP9 to MMP2 activity negatively correlated with paw inflammation at the 8 h timepoint. We postulate that the CXCL1 and CCL2 as well as the ratio of MMP9 to MMP2 activity may serve as predictive biomarkers for the timecourse of inflammation-associated locomotor impairment. These data define opportunities for the future development of a point-of-care device to objectively quantify biomarkers for inflammatory pain states.

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.

Topical Fixed-Dose Combinations: Current in vitro methodologies for pre-clinical development

The combination of two or more active pharmaceutical ingredients in the same dosage form - fixed-dose combination products - for topical administration represents a promising therapeutic approach for treating several pathologies, including pain. The pre-clinical development of fixed-dose combination products aims to characterize the interactions between the different APIs and ensure that the final medicinal product has the required safety characteristics. To this end, there are several regulatory accepted in vitro tests to assess the safety of medicinal products intended for cutaneous administration. In turn, the evaluation of anti-inflammatory activity should be based on models described in the scientific literature, as there are no models fully validated by competent entities. Therefore, the present work presents the information regarding accepted in vitro tests to assess the safety of topical products and the most used methods to assess anti-inflammatory activity. Additionally, a new approach to select a fixed-dose combination product with the potential to enhance the therapeutic effects of the individual active pharmaceutical ingredients is rationalized by integrating the overall effects on several targets relevant for inflammation and pain management in one numeric index.

High leukotriene B4 serum levels increase risk of painful diabetic neuropathy among type 2 diabetes mellitus patients

Background

Painful diabetic neuropathy is one of the most common complications of type 2 diabetes mellitus, with approximately 30–50% of people will experience diabetic neuropathy. Chronic hyperglycemia will cause an inflammatory process that will trigger an immune response included leukotrienes. Leukotriene B4 is associated with hemoglobin glycation levels. This study aimed to determine high serum leukotriene B4 levels and other factors as a risk factor for painful diabetic neuropathy in type 2 diabetes mellitus patient.

Results

Forty-two subjects with 22 cases (median age 56.5 ± 4.9 years) and 20 controls (median age 56.5 ± 5.2 years) group were collected. In bivariate analysis, significant factor for high risk PDN was high leukotriene B4 serum level (OR 5.10; 95% CI 1.34–19.4, p 0.014). Meanwhile, insignificant factors were anti-diabetic drugs (OR 2.139; 0.62–7.37; p = 0.226), and duration of diabetes mellitus (OR 2.282; 0.56–9.25; p = 0.315). Independent risk factor was serum leukotriene B4 levels (OR 5.10; 95% CI 1.336–19.470; p = 0.017).

Conclusions

In this study, high leukotriene B4 serum levels increase the risk of painful diabetic neuropathy among type 2 diabetes mellitus. The leukotriene B4 may consider as a potential biomarker for early detection in high risk for PDN and early treatment.

In vivo anti-inflammatory, anti-nociceptive, and in vitro antioxidant efficacy, and acute oral toxicity effects of the aqueous and methanolic stem bark extracts of Lonchocarpus eriocalyx (Harms.)

Oxidative stress causes and drives many agonising inflammatory conditions, which cause disability, financial burden, and emotional stress. The current anti-inflammatory, analgesic, and antioxidant agents are associated with adverse effects, inaccessibility, high costs, and low efficacies, thereby warranting the need for alternatives, especially from natural sources. Lonchocarpus eriocalyx plant is traditionally used in Kenyan communities to treat various inflammatory and oxidative stress-associated diseases; however, its pharmacologic efficacy and safety have not been empirically validated, hence this study. The in vivo antiinflamatory and antinociceptive efficacy of the aqueous and methanolic stem bark extracts of L. eriocalyx were determined using the xylene-induced ear oedema, and the acetic acid-induced writhing techniques, respectively, in experimental mice. Also, in vitro antioxidant activities of the studied plant extracts were investigated using the Thiobarbituric acid test for lipid peroxidation, 1, 1-diphenyl -2-picrylhydrazyl (DPPH), and Ferric reducing antioxidant power standard assay methods. Moreover, the studied extracts' acute oral toxicity effects were investigated according to the Organisation for Economic Corporation and Development (OECD) guidelines. The studied plant extracts showed significant dose-dependent inhibitions of oedema and writhing, depicting their anti-inflammatory and antinociceptive efficacy. Besides, the extracts revealed significant inhibitions of in vitro lipid peroxidation in varying degrees. Notably, the extracts demonstrated very strong DPPH radical scavenging and ferric-reducing antioxidant efficacies. Furthermore, the two studied plant extracts did not elicit acute oral toxicity, with LD50 values of >2000 mg/kg BW, hence were considered safe. The anti-inflammatory, antinociceptive, and in vitro antioxidant efficacies of these extracts were attributed to antioxidant phytocompounds with diverse pharmacologic effects, especially through the amelioration of oxidative stress. Further studies on the anti-inflammatory, antinociceptive and antioxidant mechanism(s) and isolation and characterisation of responsible compounds are encouraged to spur the development of affordable, accessible, safe, and efficacious drugs.

Effect of Kinesio taping on delayed-onset muscle soreness in elite athletes

BACKGROUND

This research analyzes the effect of Kinesio taping on delayed-onset muscle soreness in elite athletes because delayed-onset muscle soreness increases the risk of injury in sports.

METHODS

Elite female volleyball players (n=31) were randomly divided into experimental (n=16, with Kinesio taping of the knee) and control (n=15) groups. To elicit delayed-onset soreness in knee joint muscles, the protocol that we used consisting of downhill running, visual analog pain score assessment, and measurements of serum interleukin-6 and creatine kinase concentrations immediately and after 24 hours, 48 hours, and 72 hours.

RESULTS

Compared with the control group, the pain reported by the athletes with Kinesio taping decreased 24 hours and 48 hours (P<0.05) after running, but there was no significant difference 72 hours (P<0.05) after running. Interleukin-6 concentrations were lower in the athletes with Kinesio taping than those in the control group immediately and 24 hours (P<0.05) after running, but there was no significant difference 48 hours and 72 hours (P<0.05) after running. There were no significant differences (P>0.05) in creatine kinase concentrations.

CONCLUSIONS

The use of Kinesio taping in elite athletes is an effective protective strategy for alleviating pain symptoms caused by delayed-onset muscle soreness, but it is not effective to alleviate the skeletal muscle microinjury caused by delayed-onset muscle soreness.

Chronic pain and weight regain in a lifestyle modification trial

Objective

Obesity and chronic pain often co‐occur and exert bidirectional influences on one another. How patients with obesity and chronic pain respond to weight loss treatments, however, remains unclear. This study evaluated body weight, physical activity, and diet outcomes in participants with and without chronic pain in a 2‐year behavioral weight loss trial.

Methods

An analytical cohort of 397 adults was assembled from a Midwestern healthcare system that participated in the larger trial. Participants with chronic pain 1 year prior to, or during, the trial were identified using a validated medical records algorithm. Mixed models were used to estimate changes in outcomes over 24 months.

Results

One‐third of participants (n = 130) had chronic pain. After adjustment for age, sex, body mass index, and trial arm, weight loss was similar in both groups at 6‐months (−7.0 ± 0.8 kg with chronic pain vs. −7.7 ± 0.6 kg without). Participants with chronic pain had significantly less weight loss at 24‐months relative to those without (−3.6 ± 0.5 vs. −5.2 ± 0.4 kg; p = 0.007). Physical activity, screen time, dietary fat, fruit/vegetable consumption, and sugar‐sweetened beverage intake improved similarly in both groups over time.

Conclusions

Participants with chronic pain lost ∼33% less weight over 2 years, which was driven by greater weight regain after the first 6 months. Future research should test tailored weight loss maintenance strategies for individuals with chronic pain.

An Investigation of the Molecular Mechanisms Underlying the Analgesic Effect of Jakyak-Gamcho Decoction: A Network Pharmacology Study

Herbal drugs have drawn substantial interest as effective analgesic agents; however, their therapeutic mechanisms remain to be fully understood. To address this question, we performed a network pharmacology study to explore the system-level mechanisms that underlie the analgesic activity of Jakyak-Gamcho decoction (JGd; Shaoyao-Gancao-Tang in Chinese and Shakuyaku-Kanzo-To in Japanese), an herbal prescription consisting of Paeonia lactiflora Pallas and Glycyrrhiza uralensis Fischer. Based on comprehensive information regarding the pharmacological and chemical properties of the herbal constituents of JGd, we identified 57 active chemical compounds and their 70 pain-associated targets. The JGd targets were determined to be involved in the regulation of diverse biological activities as follows: calcium- and cytokine-mediated signalings, calcium ion concentration and homeostasis, cellular behaviors of muscle and neuronal cells, inflammatory response, and response to chemical, cytokine, drug, and oxidative stress. The targets were further enriched in various pain-associated signalings, including the PI3K-Akt, estrogen, ErbB, neurotrophin, neuroactive ligand-receptor interaction, HIF-1, serotonergic synapse, JAK-STAT, and cAMP pathways. Thus, these data provide a systematic basis to understand the molecular mechanisms underlying the analgesic activity of herbal drugs.

Acute Oral Toxicity and Anti-inflammatory and Analgesic Effects of Aqueous and Methanolic Stem Bark Extracts of Piliostigma thonningii (Schumach.)

Inflammation and pain are devastating conditions characterizing many diseases. Their manifestation ranges from mild body discomfort, to a debilitating experience, which may culminate in organ failure or death. In conventional medicine, corticosteroids, nonsteroidal anti-inflammatory drugs, opioids, and adjuvants are utilized to manage symptoms related to pain and inflammation. Despite their reported successes, these agents are only palliative, debatably inaccessible, unaffordable, and cause many undesirable side effects. As a result, the search for alternative and complementary therapies is warranted. Medicinal plants have been intensively utilized by humans for a long time to treat various ailments. In spite of their reported efficacies, empirical scientific data supporting their healing claims is scanty. P. thonningii (Schumach.) has been used in African traditional medicine, especially by traditional herbalists in Nigeria and Kenya, to treat conditions associated with inflammation. Even though analgesic, anti-inflammatory, and toxicity studies have been performed on leaf extracts, and some of their isolated compounds in Nigeria, there is scanty data supporting the use of stem bark extracts, which are commonly utilized in Kenya for pain, and inflammation management. Moreover, scientific data regarding safety and toxicity of the stem bark extracts of P. thonningii utilized in Kenya by traditional herbalists are inadequate. Based on this background, acute oral toxicity evaluation of the aqueous and methanolic stem bark extracts of P. thonningii, in Swiss albino mice, was performed according to the OECD/OCDE (2008) guidelines. Anti-inflammatory activities were investigated using the xylene-induced ear oedema in mice, whereas analgesic activities were examined following the acetic acid-induced writhing technique. The acute oral toxicity data was analyzed, and interpreted according to the OECDE (2008) guidelines. Anti-inflammatory and analgesic activities data were tabulated on MS Excel, and exported to GraphPad Prism (v8.3). Descriptive statistics were computed, and expressed as mean ± SEM. Thereafter, One-Way ANOVA followed by Tukey's test was performed. p < 0.05 was considered statistically significant. All the studied plant extracts had LD₅₀ values > 2000 mg/kg bw, and were hence deemed to be nontoxic according to OECD/OCDE document no. 425. The results showed that the acetic acid-induced writhing frequency in mice administered the aqueous stem bark extract of P. thonningii, at a dose of 500 mg/kg bw, was not significantly different from that recorded for mice which received the reference drug (acetylsalicylic acid 75 mg) (p > 0.05). Additionally, at all the studied extract doses, significantly lower acetic acid-induced writhing frequencies were recorded in mice that received the aqueous stem bark extract of P. thonningii, compared with the writhing frequencies in mice that received the methanolic extract of the same plant (p < 0.05). On the other hand, the aqueous stem bark extract of P. thonningii, at doses of 100 mg/kg bw and 500 mg/kg bw, and the methanolic stem bark extract of the same plant, at a dose level of 500 mg/kg bw, exhibited significantly higher percentage inhibitions of xylene-induced oedema than the percentage inhibitions shown by the reference drug (dexamethasone 1 mg/kg bw) (p < 0.05). Generally, the aqueous stem bark extract of P. thonningii, at all the studied dose levels, caused significantly higher inhibitions of xylene-induced ear oedema in mice, compared with the percentage inhibitions shown by methanolic stem bark (p < 0.05). Therefore, the aqueous, and methanolic stem bark extracts of P. thonningii, grown in Kenya, possess peripheral analgesic and anti-inflammatory activities in Swiss albino mice. Hence, they have a potential of offering safe analgesic, and anti-inflammatory compounds. Further studies aimed at isolating, elucidating, and characterizing bioactive components from the studied extracts are recommended. Moreover, specific mode(s) through which these extracts exert the reported bioactivities should be established. Further toxicological investigations involving the studied plant extracts are encouraged to fully establish their safety.

Efficacy of Sucrose in Reducing Pain during Immunization among 10- to 18-Month-Old Infants and Young Children: A Randomized Controlled Trial

PURPOSE

Sucrose is recommended to reduce pain associated with vaccination in neonates. However, research results concerning its effectiveness in infants and young children are inconclusive. This study aims to determine the efficacy of sucrose administration in reducing pain during immunization in 10- to 18-month-old infants and young children as assessed by behavioral pain parameters, crying time, and saliva substance (P) concentration.

DESIGN AND METHODS

This was a double-blind, randomized controlled trial and included healthy infants and young children undergoing their 10- to 18-month immunization. Behavioral pain outcome was measured during, and shortly after the last injection. The infant's pain was also measured by a salivary test using substance (P), and videotaping of crying time.

RESULTS

The study results indicate that, compared with a placebo group, the sucrose group had significantly less pain post-immunization (F (1,129) = 1.72, p = 0.001). Moreover, substance (P) was lower in the intervention group post-immunization, and it could be considered a good predictor of pain reduction associated with immunization.

CONCLUSIONS

Sucrose administration during immunization injection helps in reducing pain, which is one of the most critical factors affecting compliance with the immunization schedule. Substance (P) measurement can be used as a predictor of immunization pain level in 10- to 18-month-old infants and young children.

PRACTICE IMPLICATIONS

Sucrose is an effective method to reduce needle pain during immunization; therefore, healthcare providers should administer sucrose as a pain relief intervention in the immunization clinical setting.

The Effects of Grounding (Earthing) on Bodyworkers' Pain and Overall Quality of Life: A Randomized Controlled Trial

BACKGROUND

It is well known that massage therapists routinely develop a number of health problems related to their profession.

PURPOSE

To determine the effects of grounding on massage therapists' quality of life and pain. Grounding, refers to being in direct body contact with the ground, such as walking barefoot on humid soil or on grass.

SETTING

The Chopra Center for Well-Being in Carlsbad, California, USA.

PARTICIPANTS

Sixteen massage therapists (mean age 42.8 years).

RESEARCH DESIGN AND INTERVENTION

A stepped wedge cluster design was incorporated into a 6-week double-blind Randomized Controlled Trial (RCT) procedure with massage therapists assigned randomly into one of two cohorts. Therapists were not grounded for the first week, were grounded while working on clients and at home while sleeping for the next four weeks, and then ungrounded for the last week.

OUTCOME MEASURES

Prior to, during, and immediately following the intervention, participants completed standardized questionnaires reporting on pain, physical function, anxiety, depression, fatigue/tiredness, sleep disturbance and number of hours of sleep, number of clients worked on per working day, energy, and emotional and mental stress.

RESULTS

As a group, therapists experienced significant increases in physical function and energy and significant decreases in fatigue, depressed mood, tiredness and pain while grounded as compared to not being grounded. At one-month following the study, physical function was also increased and depressed mood and fatigue were decreased.

CONCLUSIONS

We observed consistent beneficial effects of grounding in domains highly relevant to massage therapists, namely pain, physical function, and mood. These findings, combined with prior results from this trial indicating improvements in inflammatory biomarkers, blood viscosity and heart rate variability (HRV), suggest that grounding is beneficial to massage therapists in multiple domains relevant to their occupation, supporting overall health and quality of life.

Effects of anaesthesia and analgesia on long-term outcome after total knee replacement: A prospective, observational, multicentre study

BACKGROUND

Perioperative regional anaesthesia may protect from persistent postsurgical pain (PPSP) and improve outcome after total knee arthroplasty (TKA).

OBJECTIVES

Aim of this study was to evaluate the impact of regional anaesthesia on PPSP and long-term functional outcome after TKA.

DESIGN

A web-based prospective observational registry.

SETTING

Five Italian Private and University Hospitals from 2012 to 2015.

PATIENTS

Undergoing primary unilateral TKA, aged more than 18 years, informed consent, American Society of Anesthesiologists (ASA) physical status classes 1 to 3, no previous knee surgery.

INTERVENTION(S)

Personal data (age, sex, BMI and ASA class), preoperative pain assessed by numerical rating scale (NRS) score, and risk factors for PPSP were registered preoperatively. Data on anaesthetic and analgesic techniques were collected. Postoperative pain (NRS), analgesic consumption, major complications and patient satisfaction were registered up to the time of discharge. PPSP was assessed by a blinded investigator during a phone call after 1, 3 and 6 months, together with patient satisfaction, quality of life (QOL) and walking ability.

MAIN OUTCOME MEASURES

Experience of PPSP according to the type of peri-operative analgesia.

RESULTS

Five hundred sixty-three patients completed the follow-up. At 6 months, 21.6% of patients experienced PPSP, whereas autonomy was improved only in 56.3%; QOL was worsened or unchanged in 30.7% of patients and improved in 69.3%. Patients receiving continuous regional anaesthesia (epidural or peripheral nerve block) showed a lower NRS through the whole peri-operative period up to 1 month compared with both single shot peripheral nerve block and those who did not receive any type of regional anaesthesia. No difference was found between these latter two groups. Differences in PPSP at 3 or 6 months were not significantly affected by the type of anaesthesia or postoperative analgesia. A higher NRS score at 1 month, younger age, history of anxiety or depression, pro-inflammatory status, higher BMI and a lower ASA physical status were associated with a higher incidence of PPSP and worsened QOL at 6 months.

CONCLUSION

Continuous regional anaesthesia provides analgesic benefit for up to 1 month after surgery, but did not influence PPSP at 6 months. Better pain control at 1 month was associated with reduced PPSP. Patients with higher expectations from surgery, enhanced basal inflammation and a pessimistic outlook are more prone to develop PPSP.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02147730.

Effects of anaesthesia and analgesia on long-term outcome after total knee replacement: A prospective, observational, multicentre study

BACKGROUND

Perioperative regional anaesthesia may protect from persistent postsurgical pain (PPSP) and improve outcome after total knee arthroplasty (TKA).

OBJECTIVES

Aim of this study was to evaluate the impact of regional anaesthesia on PPSP and long-term functional outcome after TKA.

DESIGN

A web-based prospective observational registry.

SETTING

Five Italian Private and University Hospitals from 2012 to 2015.

PATIENTS

Undergoing primary unilateral TKA, aged more than 18 years, informed consent, American Society of Anesthesiologists (ASA) physical status classes 1 to 3, no previous knee surgery.

INTERVENTION(S)

Personal data (age, sex, BMI and ASA class), preoperative pain assessed by numerical rating scale (NRS) score, and risk factors for PPSP were registered preoperatively. Data on anaesthetic and analgesic techniques were collected. Postoperative pain (NRS), analgesic consumption, major complications and patient satisfaction were registered up to the time of discharge. PPSP was assessed by a blinded investigator during a phone call after 1, 3 and 6 months, together with patient satisfaction, quality of life (QOL) and walking ability.

MAIN OUTCOME MEASURES

Experience of PPSP according to the type of peri-operative analgesia.

RESULTS

Five hundred sixty-three patients completed the follow-up. At 6 months, 21.6% of patients experienced PPSP, whereas autonomy was improved only in 56.3%; QOL was worsened or unchanged in 30.7% of patients and improved in 69.3%. Patients receiving continuous regional anaesthesia (epidural or peripheral nerve block) showed a lower NRS through the whole peri-operative period up to 1 month compared with both single shot peripheral nerve block and those who did not receive any type of regional anaesthesia. No difference was found between these latter two groups. Differences in PPSP at 3 or 6 months were not significantly affected by the type of anaesthesia or postoperative analgesia. A higher NRS score at 1 month, younger age, history of anxiety or depression, pro-inflammatory status, higher BMI and a lower ASA physical status were associated with a higher incidence of PPSP and worsened QOL at 6 months.

CONCLUSION

Continuous regional anaesthesia provides analgesic benefit for up to 1 month after surgery, but did not influence PPSP at 6 months. Better pain control at 1 month was associated with reduced PPSP. Patients with higher expectations from surgery, enhanced basal inflammation and a pessimistic outlook are more prone to develop PPSP.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02147730

Neuropathic Pain after Shoulder Arthroplasty: Prevalence, Impact on Physical and Mental Function, and Demographic Determinants

Purpose: The objectives of this survey study were to provide an estimate of the prevalence of neuropathic pain (NP) and to explore the cross-sectional and longitudinal group differences postoperatively. Method: A cohort of consecutive patients who had undergone total shoulder arthroplasty (TSA), reverse shoulder arthroplasty (RSA), or humeral head replacement (HHR) were surveyed within an average of 3.8 years after surgery. Questionnaires completed at the time of the survey were the Self-Administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) pain scale, the visual analogue scale (VAS) for pain, the Western Ontario Osteoarthritis of the Shoulder (WOOS) index, the Patient Health Questionnaire-9 (PHQ-9), and a satisfaction questionnaire. Results: Of the 141 candidates who were invited to participate in the study, 115 patients participated (85 TSA, 21 HHR, and 9 RSA), for an 82% response rate. Five patients (4%) met the criteria for NP, of whom one had a loosening of the prosthesis and required further surgery. Having NP was associated with greater pain (VAS; p=0.001), greater depression (PHQ-9; p=0.001), more disability (WOOS; p=0.030), and less satisfaction with the surgery (p=0.014). There was no relationship between the presence of NP and patients' age, sex, preoperative pain, range of motion results, or WOOS scores (p>0.05). Conclusions: Persistent pain of neuropathic origin is not common after shoulder arthroplasty, but it is a significant contributor to poor mental and physical well-being and thus warrants further research.

[Upcoming value of gene expression analysis in rheumatology]

Rheumatoid arthritis (RA) is a chronic inflammatory disease of unknown etiology, which involves disturbance in immune system signaling pathway functions, damage of other tissues, pain and joint destruction. Modern treatment attempts to improve pathophysiological and biochemical mechanisms damaged by the disease. However, due to the RA patient heterogeneity personalized approach to treatment is required; the choice of personalized treatment is complicated by the variability of patient's response to treatment. Gene expression analysis might serve a tool for the disease control and therapy personification for inhibition of inflammation and pain as well as for prevention of joint destruction.

The relationship between serum leptin level and disease activity and inflammatory markers in fibromyalgia patients

OBJECTIVE

The aim of this study was to investigate whether there is a correlation between serum leptin level, disease activity and inflammation markers in patients with fibromyalgia syndrome (FMS).

METHODS

A total of 48 patients with FMS diagnosed according to the 1990 American College of Rheumatology criteria were included in the study, as well as 36 healthy women as controls. The Visual Analogue Scale was used to gauge pain severity, the Fibromyalgia Impact Questionnaire was used to assess physical function, the 36-Item Short Form Health Survey was used to examine quality of life, and depression was measured with the Beck Depression Inventory. Blood samples were examined for erythrocyte sedimentation rate (ESR), C-reactive protein level (CRP), high-sensitivity CRP level (hsCRP), the neutrophil-to-lymphocyte ratio (NLR), and the serum leptin level was determined using the enzyme-linked immunosorbent assay method.

RESULTS

The serum leptin level in patients with FMS was significantly higher than in the healthy group. However, no significant relationship was found between leptin level and clinical and inflammatory parameters. In addition, there were no significant differences between the patients and the control group in measurements of ESR, CRP, hsCRP, or NLR.

CONCLUSION

A higher serum leptin level in patients with FMS suggested that leptin may play role in the pathogenesis of FMS, yet there was no relationship between leptin and clinical and inflammatory parameters, suggesting that leptin is not an indicator of disease activity in FMS. Additional research should be performed with larger patient groups.

Comparison of cortisol and inflammatory response between aged and middle-aged patients undergoing total hip arthroplasty: a prospective observational study

Background

To investigate the differences in the perioperative serum cortisol, C-reactive protein (CRP) and interleukin-6 (IL-6) levels between aged and middle-aged patients undergoing total hip arthroplasty (THA).

Methods

Sixty patients (30 aged and 30 middle-aged) undergoing THA for osteoarthritis between August 2016 and January 2017 participated in this study. Blood samples were collected preoperatively and at 6 hours, 24 hours and 3 days after surgery to measure the cortisol, CRP and IL-6 concentrations. The clinical outcomes were assessed using the visual analogue scale (VAS) pain score and Harris hip score (HHS).

Results

No significant differences were found between the two groups before the operation in the cortisol, IL-6 and CRP levels; the VAS score; or the HHS. Cortisol was significantly lower at 6 hours after surgery in the aged group than in the middle-aged group (P < 0.05). IL-6 at 6 and 24 hours after surgery, CRP at 3 days after surgery and the VAS score at 6 and 24 hours after surgery in the aged group were significantly higher than those in the middle-aged group (P < 0.05). In the aged group, weak correlations were found between the cortisol concentration 6 hours after THA and the IL-6 level 24 hours after THA (r = −0.37, P = 0.04) and between the IL-6 level 6 hours after THA and the VAS score 24 hours after THA (r = 0.42, P = 0.02).

Conclusion

Aged patients showed lower cortisol levels at 6 hours after surgery and higher IL-6 levels at 6 and 24 hours after surgery than middle-aged patients undergoing THA.

The clinical utility of gene expression examination in rheumatology

Rheumatoid arthritis (RA) is a chronic inflammatory disease with unknown etiology that affects various pathways within the immune system, involves many other tissues and is associated with pain and joint destruction. Current treatments fail to address pathophysiological and biochemical mechanisms involved in joint degeneration and the induction of pain. Moreover, RA patients are extremely heterogeneous and require specific treatments, the choice of which is complicated by the fact that not all patients equally respond to therapy. Gene expression analysis offer tools for patient management and personalization of patient’s care to meet individual needs in controlling inflammation and pain and delaying joint destruction.

Challenges in translational drug research in neuropathic and inflammatory pain: the prerequisites for a new paradigm

AIM

Despite an improved understanding of the molecular mechanisms of nociception, existing analgesic drugs remain limited in terms of efficacy in chronic conditions, such as neuropathic pain. Here, we explore the underlying pathophysiological mechanisms of neuropathic and inflammatory pain and discuss the prerequisites and opportunities to reduce attrition and high-failure rate in the development of analgesic drugs.

METHODS

A literature search was performed on preclinical and clinical publications aimed at the evaluation of analgesic compounds using MESH terms in PubMed. Publications were selected, which focused on (1) disease mechanisms leading to chronic/neuropathic pain and (2) druggable targets which are currently under evaluation in drug development. Attention was also given to the role of biomarkers and pharmacokinetic-pharmacodynamic modelling.

RESULTS

Multiple mechanisms act concurrently to produce pain, which is a non-specific manifestation of underlying nociceptive pathways. Whereas these manifestations can be divided into neuropathic and inflammatory pain, it is now clear that inflammatory mechanisms are a common trigger for both types of pain. This has implications for drug development, as the assessment of drug effects in experimental models of neuropathic and chronic pain is driven by overt behavioural measures. By contrast, the use of mechanistic biomarkers in inflammatory pain has provided the pharmacological basis for dose selection and evaluation of non-steroidal anti-inflammatory drugs (NSAIDs).

CONCLUSION

A different paradigm is required for the identification of relevant targets and candidate molecules whereby pain is coupled to the cause of sensorial signal processing dysfunction rather than clinical symptoms. Biomarkers which enable the characterisation of drug binding and target activity are needed for a more robust dose rationale in early clinical development. Such an approach may be facilitated by quantitative clinical pharmacology and evolving technologies in brain imaging, allowing accurate assessment of target engagement, and prediction of treatment effects before embarking on large clinical trials.

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.

Adenosine for postoperative analgesia: A systematic review and meta-analysis

Purpose

Perioperative infusion of adenosine has been suggested to reduce the requirement for inhalation anesthetics, without causing serious adverse effects in humans. We conducted a meta-analysis of randomized controlled trials evaluating the effect of adenosine on postoperative analgesia.

Methods

We retrieved articles in computerized searches of Scopus, Web of Science, PubMed, EMBASE, and Cochrane Library databases, up to July 2016. We used adenosine, postoperative analgesia, and postoperative pain(s) as key words, with humans, RCT, and CCT as filters. Data of eligible studies were extracted, which included pain scores, cumulative opioid consumption, adverse reactions, and vital signs. Overall incidence rates, relative risk (RR), and 95% confidence intervals (CI) were calculated employing fixed-effects or random-effects models, depending on the heterogeneity of the included trials.

Results

In total, 757 patients from 9 studies were included. The overall effect of adenosine on postoperative VAS/VRS scores and postoperative opioid consumption was not significantly different from that of controls (P >0.1). The occurrence of PONV and pruritus was not statistically significantly different between an adenosine and nonremifentanil subgroup (P >0.1), but the rate of PONV occurrence was greater in the remifentanil subgroup (P <0.01). Time to first postoperative analgesic requirement in the adenosine group was not significantly difference from that of the saline group (SMD = 0.07, 95%CI: −0.28 to 0.41, P = 0.71); but this occurred significantly later than with remifentanil (SMD = 1.10, 95%CI: 2.48 to 4.06, P < 0.01). Time to hospital discharge was not significantly different between the control and adenosine groups (P = 0.78). The perioperative systolic blood pressure was significantly lower in the adenosine than in the control group in the mannitol subgroup (P < 0.01). The incidence of bradycardia, transient first- degree atrioventricular block, and tachycardia was not significantly different between the adenosine and control groups (P > 0.1).

Conclusion

Adenosine has no analgesic effect or prophylactic effect against PONV, but reduce systolic blood pressure and heart rates. Adenosine may benefit patients with hypertension, ischemic heart disease, and tachyarrhythmia, thereby improving cardiac function.

Stress, Inflammation and Pain: A Potential Role for Monocytes in Fibromyalgia-related Symptom Severity

The possibility that immunological changes might contribute to symptom severity in fibromyalgia (FM) prompted this proof-of-concept study to determine whether differences in monocyte subpopulations might be present in persons with FM compared with healthy controls. Relationships were assessed by comparing specific symptoms in those with FM (n = 20) and patterns of monocyte subpopulations with healthy age-matched and gender-matched controls (n = 20). Within the same time frame, all participants provided a blood sample and completed measures related to pain, fatigue, sleep disturbances, perceived stress, positive and negative affect and depressed mood (and the Fibromyalgia Impact Questionnaire for those with FM). Monocyte subpopulations were assessed using flow cytometry. No differences were observed in total percentages of circulating monocytes between the groups; however, pain was inversely correlated with percentages of circulating classical (r = -0.568, p = 0.011) and intermediate (r = -0.511, p = 0.025) monocytes in the FM group. Stress and pain were highly correlated (r = 0.608, p = 0.004) in the FM group. The emerging pattern of changes in the percentages of circulating monocyte subpopulations concomitant with higher ratings of perceived pain and the correlation between stress and pain found in the FM group warrant further investigation. Copyright © 2015 John Wiley & Sons, Ltd.

The Role of C Fibers in Spinal Microglia Induction and Possible Relation with TRPV3 Expression During Chronic Inflammatory Arthritis in Rats

Introduction:

Stimulation of peptidergic fibers activates microglia in the dorsal horn. Microglia activation causes fractalkine (FKN) release, a neuron-glia signal, which enhances pain. The transient vanilloid receptor 1 (TRPV1) mediates the release of neuropeptides, which can subsequently activate glia. TRPV1 and TRPV2 are generally expressed on C and Aδ fibers, respectively. Expression of both proteins is upregulated during inflammation, but expression of TRPV3 after induction of inflammation is unclear.

Methods:

Adult male Wistar rats were used in all experiments. Arthritis was induced in them by single subcutaneous injection of complete Freund’s adjuvant (CFA) in their right hindpaws. Resiniferatoxin (RTX) was used to eliminate peptidergic fibers. We examined the relation between FKN and TRPV3 expression by administration of anti-FKN antibody.

Results:

Our study findings indicated that 1) spinal TRPV3 was mostly expressed on nonpeptidergic fibers, 2) expression of spinal TRPV3 increased following inflammation, 3) elimination of peptidergic fibers decreased spinal TRPV3 expression, 4) alteration of hyperalgesia was compatible with TRPV3 changes in RTX-treated rat, and 5) anti-FKN antibody reduced spinal TRPV3 expression.

Discussion:

It seems that the hyperalgesia variation during different phases of CFA-induced arthritis correlates with spinal TRPV3 expression variation on peptidergic fibers. Moreover, spinal microglial activation during CFA inflammation is involved in TRPV3 expression changes via FKN signaling.

Effect of Preoperative Inflammatory Status and Comorbidities on Pain Resolution and Persistent Postsurgical Pain after Inguinal Hernia Repair

Poor acute pain control and inflammation are important risk factors for Persistent Postsurgical Pain (PPSP). The aim of the study is to investigate, in the context of a prospective cohort of patients undergoing hernia repair, potential risk factors for PPSP. Data about BMI, anxious-depressive disorders, neutrophil-tolymphocyte ratio (NLR), proinflammatory medical comorbidities were collected. An analysis for correlation between comorbidities and PPSP was performed in those patients experiencing chronic pain at 3 months after surgery. Tramadol resulted less effective in pain at movement in patients with a proinflammatory status. Preoperative hypertension and NLR > 4 were correlated with PPSP intensity. Regional anesthesia was significantly protective on PPSP when associated with ketorolac. Patients with pain at 1 month were significantly more prone to develop PPSP at 3 months. NSAIDs or weak opioids are equally effective on acute pain and on PPSP development after IHR, but Ketorolac has better profile in patients with inflammatory background or undergoing regional anesthesia. Drug choice should be based on their potential side effects, patient's profile (comorbidities, preoperative inflammation, and hypertension), and type of anesthesia. Close monitoring is necessary to early detect pain conditions more prone to progress to a chronic syndrome.

Effect of dexmedetomidine and cold stress in a rat model of neuropathic pain: Role of interleukin-6 and tumor necrosis factor-α

Dexmedetomidine (Dex) is a novel Alpha 2-adrenoceptor agonist. It decreases sympathetic tone and attenuates the stress responses to anesthesia and surgery. People exposed to cold suffer unpleasant thermal pain, which is experienced as stress and causes the release of noradrenaline from the sympathetic terminals. The present study investigated the effects of cold stress and dexmedetomidine on chronic constriction injury (CCI) model of the sciatic nerve in rats. Sixty four male Wistar rats were divided into seven groups of eight rats each: repeated cold stress (RCS) group, sham RCS group, CCI group, sham CCI group, Dex-treated group received a single dose of Dex (5 μg/kg), CCI+Dex group, CCI+RCS group. Interleukin-6 (IL-6) and tumor necrosis factor- alpha (TNF-α) levels in the serum were measured by enzyme-linked immunosorbent assay. The mean body weight of CCI, RCS, CCI+RCS, CCI+Dex and RCS+Dex groups decreased significantly compared with pre-values. Dexmedetomidine and CCI caused significant changes of the systolic, diastolic and mean blood pressure. Both RCS and CCI groups showed significant decreased of reaction time in the hot plate test. The RCS and CCI groups demonstrated a significant mechanical hyperalgesia, while pain threshold was increased in the RCS+Dex group. A significant decrease of serum IL-6 and TNF-α was demonstrated in CCI+RCS and CCI+Dex groups. The therapeutic effectiveness of dexmedetomidine in neuropathic pain may be through inhibition of proinflammatory cytokines, primarily IL-6 and TNF-α. Moreover, cold stress may result in increased resistance to neuropathic pain.

DXXK exerts anti-inflammatory effects by inhibiting the lipopolysaccharide-induced NF-κB/COX-2 signalling pathway and the expression of inflammatory mediators

ETHNOPHARMACOLOGICAL RELEVANCE

Diao Xin Xue Kang (DXXK) is the active pharmaceutical ingredient of the traditional Chinese medicinal product DXXK capsules, which have been approved for the treatment of cardiovascular disease and have been widely used clinically in China for many years with distinct curative effects. In March 2012, DXXK capsules were approved in the Netherlands, making them the first traditional herbal medicinal product (THMP) made outside of Europe.

AIM

To assess the anti-inflammatory effects of DXXK and the underlying mechanisms at the cellular and molecular levels.

MATERIALS AND METHODS

In this study, lipopolysaccharide (LPS) was used to induce inflammation in RAW 264.7 cells. The sulphorhodamine B (SRB) assay was used to study the effect of DXXK on the proliferation of RAW 264.7 cells. Gene expression levels of cyclooxygenase 1 (COX-1), COX-2, tumour necrosis factor-alpha (TNF-α), IL-1β and IL-6 were assessed by reverse transcription polymerase chain reaction (RT-PCR), while COX-2 protein levels were evaluated using western blotting. The levels of PGE2 in the culture media were detected by enzyme-linked immunosorbent assay (ELISA), while TNF-α, IL-1β and IL-6 levels were detected using a Milliplex Map Mouse Cytokine Panel system. The activation and nuclear translocation of nuclear transcription factor κB (NF-κB) were studied using western blotting. In vivo studies in mice were carried out using the carrageenan-air pouch models of inflammation. In exudates, leucocytes were counted, total protein was determined using the Bradford assay, nitric oxide(NO) levels were assessed using the Griess reagent, and PGE2 and TNF-α levels were quantified by ELISA.

RESULTS

The SRB assay showed that at the doses used in this study (10, 20 and 40 μg/mL), DXXK did not affect the proliferation of RAW 264.7 cells. DXXK (10, 20 and 40 μg/mL) inhibited LPS-induced PGE2 production by down-regulating the expression of COX-2, without influencing COX-1 expression. We also demonstrated that DXXK reduced the expression of pro-inflammatory cytokines, including TNF-α, IL-1β and IL-6, at both the gene and protein levels. Furthermore, DXXK inhibited LPS-induced NF-κB activation and nuclear translocation by suppressing the phosphorylation of IκB. Consistent with the in vitro results, the in vivo studies demonstrated that DXXK reduced leucocyte counts as well as total protein, NO, PGE2 and TNF-α levels in the exudates of mice with carrageenan-air pouch inflammation.

CONCLUSIONS

The current study revealed that DXXK has a significant anti-inflammatory effect that may be attributed to its inhibitory effect on the NF-κB/COX-2 pathway and associated inflammatory mediators, including PGE2, NO, TNF-α, IL-1β and IL-6. The current study provides additional evidence of the effects of DXXK in inflammation. Based on the combination of our results and previously reported data, we propose that DXXK has multiple pharmacological effects that could be harnessed to treat systemic diseases.

Altered release of chemokines by phagocytes from fibromyalgia patients: a pilot study

Fibromyalgia (FM) is a syndrome characterized by widespread chronic pain and is associated with elevated systemic inflammatory biomarkers, and an elevated innate cellular response. The aim of this study was to determine if fibromyalgia patients have altered ability to release pro-inflammatory chemokines by isolated neutrophils and monocytes. The study participants were women diagnosed with FM (n = 6) and a control group of healthy women (HW) (n = 6). Supernatant concentrations of eotaxin (CCL11), human macrophage-derived chemokine (MDC) (CCL22) and growth regulated-oncogene (GRO-α) (CXCL1) released by both monocytes and neutrophils either resting or stimulated by LPS were determined by ELISA and compared between the FM and HW groups. Both resting and activated monocytes from FM patients released more eotaxin, MDC and GRO-α than those from HW. However, there were no significant differences in the release of chemokines from neutrophils of FM patients and the ones from healthy women. In conclusion, monocytes from women with FM are deregulated, releasing higher amounts of eotaxin, MDC and GRO-α than healthy individuals. This fact does not occur in neutrophils from women with FM.

Dexmedetomidine Analgesia Effects in Patients Undergoing Dental Implant Surgery and Its Impact on Postoperative Inflammatory and Oxidative Stress

The aim of the study was to determine whether or not dexmedetomidine- (DEX-) based intravenous infusion in dental implantation can provide better sedation and postoperative analgesia via suppressing postoperative inflammation and oxidative stress. Sixty patients were randomly assigned to receive either DEX (group D) or midazolam (group M). Recorded variables were vital sign (SBP/HR/RPP/SpO2/RR), visual analogue scale (VAS) pain scores, and observer's assessment of alertness/sedation scale (OAAS) scores. The plasma levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), antioxidant superoxide dismutase (SOD), and the lipid peroxidation product malondialdehyde (MDA) were detected at baseline and after 2, 4, and 24 h of drug administration. The VAS pain scores and OAAS scores were significantly lower for patients in group D compared to group M. The plasma levels of TNF-α, IL-6, and MDA were significantly lower in group D patients than those in group M at 2 h and 4 h. In group M, SOD levels decreased as compared to group D at 2 h and 4 h. The plasma levels of TNF-α, IL-6, and MDA were positively correlated with VAS pain scores while SOD negatively correlated with VAS pain scores. Therefore, DEX appears to provide better sedation during office-based artificial tooth implantation. DEX offers better postoperative analgesia via anti-inflammatory and antioxidation pathway.

Sciatica: detection and confirmation by new method

We need to overcome limitations of present assessment and also integrate newer research in our work about sciatica. Inflammation induces changes in the DRG and nerve root. It sensitizes the axons. Nociceptor is a unique axon. It is pseudo unipolar: both its ends, central and peripheral, behave in similar fashion. The nerve in periphery which carries these axons may selectively become sensitive to mechanical pressure--"mechanosensitized," as we coin the phrase. Many pain questionnaires are used and are effective in identifying neuropathic pain solely on basis of descriptors but they do not directly physically correlate nerve root and pain. A thorough neurological evaluation is always needed. Physical examination is not direct pain assessment but testing mobility of nerve root and its effect on pain generation. There is a dogmatic dominance of dermatomes in assessment of leg pain. They are unreliable. Images may not correlate with symptoms and pathology in about 28% of cases. Electrophysiology may be normal in purely inflamed nerve root. Palpation may help in such inflammatory setting to refine our assessment further. Confirmation of sciatica is done by selective nerve root block (SNRB) today but it is fraught with several complications and needs elaborate inpatient and operating room set up. We have used the unique property of the pseudo unipolar axon that both its ends have similar functional properties and so inject along its peripheral end sodium channel blockers to block the basic cause of the mechanosensitization namely upregulated sodium channels in the root or DRG. Thus using palpation we may be able to detect symptomatic nerve in stage of inflammation and with distal end injection, along same inflamed nerve we may be able to abolish and so confirm sciatica. Discussions of sciatica pain diagnosis tend to immediately shift and centre on the affected disc rather than the nerve. Theoretically it may be possible to detect the affected nerve by palpating the nerve and relieve pain moment we desensitize the nerve.

Cystatin C in cerebrospinal fluid is upregulated in elderly patients with chronic osteoarthritis pain and modulated through matrix metalloproteinase 9-specific pathway

OBJECTIVES

Although high abundant cystatin c (CysC) in cerebrospinal fluid (CSF) is well known, its ambiguous role associated with pain still remains unclear. This study evaluated the effects of intrathecal CysC content from chronic pain caused by osteoarthritis (OA) and the novel relationship with matrix metalloproteinases 2 and 9 (MMP2 and MMP9) in CSF.

METHODS

Samples of CSF were obtained from 8 elderly patients (65 y and above) with OA with lower limb pain for at least 6 months (OA group) and 8 sex-matched and age-matched relatively healthy elderly individuals without any pain problems (control group). The intrathecal CysC, MMP2, and MMP9 were examined by Western blotting. The analysis of CysC cleavage under different conditions was performed through silver staining and using mass-spectroscopy (SELDI-TOF) on 2 groups.

RESULTS

Expression of full-length CysC and pro-MMP2 proteins showed statistically significant upregulation (P=0.0004 vs. 0.03), and expression of MMP9 protein showed downregulation (P=0.007) in the OA group. Both MMP9 and MMP2 initiated the mechanism for full-length CysC cleavage only in the presence of CSF. However, MMP9 showed greater ability than MMP2 for CysC cleavage in control and OA groups in sliver staining. Incubation of CSF with the MMP9 inhibitor led to the suppression of CysC cleavage in SELDI-TOF.

DISCUSSION

These findings provide the first in vivo evidence on a relationship between CysC and gelatinases (MMP2 and MMP9), and could facilitate further investigation of novel interactions among these proteins within the proteomics field, especially protein-protein interactions involved in pain.

Pain after knee arthroplasty: an unresolved issue

PURPOSE

Despite the recent advances in the understanding of pain mechanisms and the introduction of new drugs and new techniques in the postoperative management, pain after total knee arthroplasty (TKA) is still an unresolved issue. It affects the quality of life and rehabilitation of an important percentage of patients undergoing TKA. The aim of this narrative review was to give an overview on pain mechanisms and multimodal pain management.

METHODS

A review of all peer-reviewed articles on pain after knee arthroplasty was performed by two reviewers. Recent articles on incisional pain mechanisms were included because of their importance in the understanding of postsurgical pain. Search was performed in Pubmed, Cochrane and Google Scholar data bases.

RESULTS

Postsurgical pain mechanisms are based on both local and systemic inflammatory reactions. Peri-operative pain management starts with the anaesthetic technique and resides on a multimodal analgesia regimen. New concepts, drugs and techniques have shown their efficacy in reducing the severity of acute postoperative pain and the risk of developing chronic pain after TKA.

CONCLUSION

This narrative review offers a clear overview of pain mechanism after knee arthroplasty and an understanding on how multimodal pain management can reduce the intensity and duration of pain after knee arthroplasty.

An intricate relationship between pain and depression: clinical correlates, coactivation factors and therapeutic targets

INTRODUCTION

An apparent clinical relationship between pain and depression has long been recognized, which makes an enormous impact on the individual health care. At present, the practical implication of such overlapping symptomatology between pain and depression is not clear, but the prevalence estimates for depression are substantially inflated among patients with chronic pain and vice versa. This interaction has been labeled as the depression-pain syndrome or depression-pain dyad.

AREAS COVERED

This article discusses the neurobiological substrates and neuroanatomical pathways involved in pain-depression dyad along with newer therapeutic targets.

EXPERT OPINION

Several key themes emerged from our review of the relationship between depression and pain. First, the diagnosis of depression in pain or vice versa is particularly challenging, and the development of better diagnostic framework that involves both pain and depression is particularly required. Secondly, the entwined relationship between pain and depression supports the possibility of common coactivating factors that results in their neurophysiological overlap. A broad understanding of the role played by the central nervous system (CNS) in the processing of pain and depression may eventually lead to the introduction of triple reuptake inhibitors, agomelatine, vilazodone and ketamine with novel mechanism of action, hence appear to be of promising potential for pain with depression.

Altered profile of chemokines in fibromyalgia patients

Background

Fibromyalgia (FM) is a syndrome characterized by widespread chronic pain. Its aetiology is still poorly understood, and there are no haematochemical or instrumental tests on which to base a diagnosis. Recent studies suggest that its pathogenesis may involve cytokines, in particular, chemokines – cytokines that regulate cell traffic under both physiological and pathological conditions. The aim of this study was to determine possible differences in the profile of systemic concentrations of chemokines between FM patients and healthy women (HW; controls).

Methods

The study participants were women diagnosed with FM ( n = 17) and a control group of HW ( n = 10). Serum concentrations of thymus and activation-regulated chemokine (TARC)/(CCL17), monokine induced by gamma-interferon (MIG)/(CXCL9), macrophage-derived chemokine (MDC)/(CCL22), interferon-inducible T-cell alpha chemoattractant (I-TAC)/(CXCL11), eotaxin (CCL11), pulmonary and activation-regulated chemokine (PARC)/(CCL18) and hemofiltrate CC-chemokine-4 (HCC-4)/(CCL16) were determined by enzyme-linked immunosorbent assay and compared between the FM and HW groups.

Results

FM patients had elevated serum levels of the following inflammatory chemokines: TARC ( P < 0.001), MIG ( P < 0.001), MDC ( P < 0.01), I-TAC ( P < 0.01) and eotaxin ( P < 0.05). No differences were found in the circulating concentrations of PARC and HCC-4 (homoeostatic chemokines).

Conclusions

Since FM patients present higher serum concentrations of inflammatory chemokines than HW, the evaluation of these biomarkers could help in the diagnosis of this syndrome.

New concepts in acute pain management: strategies to prevent chronic postsurgical pain, opioid-induced hyperalgesia, and outcome measures

Chronic postsurgical pain (CPSP) is a pain syndrome that has attracted attention for more than 10 years. CPSP is a pain syndrome that develops postoperatively and lasts for at least 2 months in the absence of other causes for pain (eg, recurrence of malignancy, chronic infection, and so forth). Pain continuing from a preexisting disease is not considered as CPSP. In this article, the authors discuss the etiopathogenesis of CPSP and interventions that can help prevent and treat this condition.