Dietary Influence on Pain via the Immune System

Association Between the Dietary Inflammatory Index and Middle Ear Disease in Adults: An NHANES Analysis

OBJECTIVE

This study aimed to investigate the relationship between the dietary inflammatory index (DII) and middle ear disease (MED) in adults using data from the National Health and Nutrition Examination Survey (NHANES) 2015 to 2020.

STUDY DESIGN

A cross-sectional analysis was conducted on a sample of American adults to explore the association between DII and MED.

SETTING

The study utilized data from 3 NHANES cycles (2015-2020), assessing the health and nutritional status of adults and children in the United States.

METHODS

We analyzed data from 3743 participants aged 20 and older, with MED defined by abnormal tympanogram results. DII was calculated based on dietary intake data recorded during the 24 hours before the interview. Logistic regression models were used to examine the association between DII and MED, adjusted for various demographic and health-related factors.

RESULTS

The results revealed a significant positive association between higher DII scores and the likelihood of MED, particularly in individuals under 60 years of age. A nonlinear relationship was identified, with a threshold effect at a DII value of 2.74, below which higher DII was associated with increased risk of MED, while the association weakened above this threshold.

CONCLUSION

This study suggests that inflammatory dietary patterns are associated with an increased risk of MED, especially in younger adults. The findings underscore the importance of dietary interventions in preventing and managing MED and warrant further prospective studies to confirm these results and understand the mechanisms by which diet affects middle ear health.

Systemic Inflammation, Sleep, and Psychological Factors Determine Recovery Trajectories for People With Neck Pain: An Exploratory Study

We conducted an explorative prospective cohort study with 6 months follow-up to 1) identify different pain and disability trajectories following an episode of acute neck pain, and 2) assess whether neuroimmune/endocrine, psychological, behavioral, nociceptive processing, clinical outcome, demographic and management-related factors differ between these trajectories. Fifty people with acute neck pain (ie, within 2 weeks of onset) were included. At baseline, and at 2, 4, 6, 12, and 26 weeks follow-up, various neuroimmune/endocrine (eg, inflammatory cytokines and endocrine factors), psychological (eg, stress symptoms), behavioral (eg, sleep disturbances), nociceptive processing (eg, condition pain modulation), clinical outcome (eg, trauma), demographic factors (eg, age), and management-related factors (eg, treatment received) were assessed. Latent class models were performed to identify outcome trajectories for neck pain and disability. Linear mixed models or the Pearson chi-square test were used to evaluate differences in these factors between the trajectories at baseline and at each follow-up assessment and over the entire 6 months period. For pain, 3 trajectories were identified. The majority of patients were assigned to the "Moderate pain - Favourable recovery" trajectory (n = 25; 50%) with smaller proportions assigned to the "Severe pain - Favourable recovery" (n = 16; 32%) and the "Severe pain - Unfavourable recovery" (n = 9; 18%) trajectories. For disability, 2 trajectories were identified: "Mild disability - Favourable recovery" (n = 43; 82%) and "Severe disability - Unfavourable recovery" (n = 7; 18%). Ongoing systemic inflammation (increased high-sensitive C-reactive protein), sleep disturbances, and elevated psychological factors (such as depression, stress and anxiety symptoms) were mainly present in the unfavorable outcome trajectories compared to the favorable outcome trajectories. PERSPECTIVE: Using exploratory analyses, different recovery trajectories for acute neck pain were identified based on disability and pain intensity. These trajectories were influenced by systemic inflammation, sleep disturbances, and psychological factors.

Proinflammatory Dietary Intake Relates to Pain Sensitivity in Chronic Nonspecific Low Back Pain: A Case-Control Study

Nonspecific chronic low back pain (nCLBP) has been associated with nutrition. Yet, it is not clear how nutritional factors and nCLBP relate to one another. Therefore, the aim of the present study was to investigate differences in diet quality and dietary intake levels between nCLBP patients and healthy controls (HCs) and explore the association between nutritional factors and pain sensitivity in nCLBP. In this case-control study, 106 participants (ie, n = 53 nCLBP and n = 53 HCs) were recruited and completed a 3-day food diary to assess their dietary intake, which allowed to generate individual diet quality scores (ie, the Healthy Eating Index-2015 and Dietary Inflammatory Index). Additionally, each participant underwent an experimental pain assessment (quantitative sensory testing) and filled out self-reported pain questionnaires. Compared to HCs, the nCLBP group showed significantly lower diet quality, higher inflammatory scores, and a lower intake of total protein, total fat, dietary fiber, omega-3 fatty acids, vitamin B6, vitamin A, beta-carotene, vitamin E, and magnesium. Pain sensitivity mainly showed a negative correlation with nutritional intakes known for anti-inflammatory properties (ie, vitamins E, D, A, B6, B12, and zinc). Interestingly, total fat, cholesterol, saturated, and monounsaturated fat intakes were found to be inversely associated with pain sensitivity. Overall, patients with nCLBP have a lower diet quality, eat more proinflammatory, have less intake of nutrients known for their anti-inflammatory and antioxidative properties, and drink less water compared to HCs. Accordingly, pain sensitivity was mainly found to be positively associated with proinflammatory dietary intake. PERSPECTIVE: This study emphasizes the association between a proinflammatory diet and nCLBP. Among nCLBP patients, positive association between increased pain sensitivity and the proinflammatory potential of a diet, highlighting the potential for individualized pain management strategies and leading to the development of novel therapeutic methods.

Phenylpropanoid-enriched broccoli seedling extract can reduce inflammatory markers and pain behavior

BACKGROUND

Pain is a worldwide problem requiring an effective, affordable, non-addictive therapy. Using the edible plant broccoli, a growth protocol was developed to induce a concentrated combinatorial of potential anti-inflammatories in seedlings.

METHODS

A growth method was utilized to produce a phenylpropanoid-rich broccoli sprout extract, referred to as Original Extract (OE). OE was concentrated and then resuspended for study of the effects on inflammation events. A rabbit disc model of inflammation and degeneration, and, a mouse model of pain behavior were used for in vivo and in vitro tests. To address aspects of mammalian metabolic processing, the OE was treated with the S9 liver microsome fraction derived from mouse, for use in a mouse in vivo study. Analytical chemistry was performed to identify major chemical species. Continuous variables were analyzed with a number of methods including ANOVA, and two-tailed t tests, as appropriate.

RESULTS

In a rabbit spine (disc) injury model, inflammatory markers were reduced, and levels of regenerative markers were increased as a result of OE treatment, both in vivo and in vitro. In a mouse pain behavioral model, after treatment with S9 liver microsome fraction, the resultant extract significantly reduced early and late pain behavior in response to a pain stimulus. The OE itself reduced pain behavior in the mouse pain model, but did not achieve the level of significance observed for S9-treated extract. Analytical chemistry undertaken on the extract constituents revealed identities of the chemical species in OE, and how S9 liver microsome fraction treatment altered species identities and proportions.

CONCLUSIONS

In vitro and in vivo results indicate that the OE, and S9-treated OE broccoli extracts are worthwhile materials to develop a non-opiate inflammation and pain-reducing treatment.

The Biology of Chronic Pain and Its Implications for Pain Neuroscience Education: State of the Art

Pain is an individualized experience for the person suffering from chronic pain. Significant strides have been made in the last few decades in understanding various biological changes that coincide with chronic pain. This state-of-the-art overview looks at the current evidence related to the biology of chronic pain and the implications these findings have on the delivery of pain neuroscience education (PNE). The paper summarizes the various (epi)genetic, neural, endocrine, and immune factors discovered and explored in the scientific literature concerning chronic pain. Each of these biological factors has various implications for the content and delivery of PNE. We discuss the future directions these biological factors have for the clinical implementation of PNE by linking the importance of behavior change, optimizing the learning environment, and using an individualized multimodal treatment approach with PNE. In addition, future directions for research of PNE based on these biological factors are provided with importance placed on individualized patient-centered care and how PNE can be used with traditional modes of care and growing trends with other care methods. PNE was originally and continues to be rooted in understanding chronic pain biology and how that understanding can improve patient care and outcomes.

Neuroendocrine and neuroimmune mechanisms underlying comorbidity of pain and obesity

Pain and obesity, as well as their associated impairments, are major health concerns. Understanding the relationship between the two is the focus of a growing body of research. However, early researches attribute increased mechanical stress from excessive weight as the main factor of obesity-related pain, which not only over-simplify the association, but also fail to explain some controversial outcomes arising from clinical investigations. This review focuses on neuroendocrine and neuroimmune modulators importantly involved in both pain and obesity, analyzing nociceptive and anti-nociceptive mechanisms based on neuroendocrine pathways including galanin, ghrelin, leptin and their interactions with other neuropeptides and hormone systems which have been reported to play roles in pain and obesity. Mechanisms of immune activities and metabolic alterations are also discussed, due to their intense interactions with neuroendocrine system and crucial roles in the development and maintenance of inflammatory and neuropathic pain. These findings have implications for health given rising rates of obesity and pain-related diagnoses, by providing novel weight-control and analgesic therapies targeted on specific pathways.

Eating habits and nutritional status of women with musculo-skeletal diseases

Different theories link chronic musculoskeletal pain with lifestyle components, including diet. However, nutritional assesment and optimization is not routinely included into the medical management of patients with muskuloskeletal diseases (MSKD). In this study we aimed to evaluate the diet and nutritional status of a group of women with MSKD and to assess the extent to which they comply with the general recommendations for a healthy diet. The results showed that 97% of the subjects included were overweight or obese, and the compliance to different general nutritional recommandations ranged between 3% to 57%. Furthermore, the quality of life of this patients measured through SF-36 question-naire was severly affected and the reported pain intensity on numeric pain scale had a mean of 8 (±1.3) in our study group. Although there are currently no specific guidelines for the nutrition of patients with chronic pain, an important first step would be to guide these patients towards an increase in diet quality and a healthy lifestyle by adhering to general nutritional recommendations regarding healthy eating.

The Inflammatory Potential of Diet and Pain Incidence: A Cohort Study in Older Adults

BACKGROUND

Despite its importance, evidence regarding pain prevention is inadequate. Leveraging the growing knowledge on how diet regulates inflammation, we examined the association of 3-year changes in the inflammatory potential of diet with pain incidence over the subsequent 3 years.

METHODS

We used data from 819 individuals aged ≥60 years and free of pain in 2012, drawn from the Spanish Seniors-ENRICA-1 cohort. The inflammatory potential of diet was estimated via a validated diet history and 2 indices: the dietary inflammatory index (DII) and the empirical dietary inflammatory index (EDII). The frequency, severity, and number of locations of incident pain were combined into a scale that classified participants as suffering from no pain, intermediate pain, or highest pain.

RESULTS

Shifting the diet toward a higher inflammatory potential was associated with subsequent increased risk of highest pain (fully-adjusted relative risk ratio [95% confidence interval] per 1-standard deviation increment in the DII and the EDII = 1.45 [1.16,1.80] and 1.21 [0.98,1.49], respectively) and intermediate pain (0.99 [0.75,1.31] and 1.37 [1.05,1.79]). The 3 components of the pain scale followed similar trends, the most consistent one being pain severity (moderate-to-severe pain: DII = 1.39 [1.11,1.74]; EDII = 1.35 [1.08,1.70]). The association of increasing DII with highest incident pain was only apparent among the less physically active participants (2.08 [1.53,2.83] vs 1.02 [0.76,1.37]; p-interaction = .002).

CONCLUSION

An increase in the inflammatory potential of diet was associated with higher pain incidence over the following years, especially among the less physically active participants. Future studies in older adults should assess the efficacy of pain prevention interventions targeting the inflammatory potential of diet.

Fish consumption, omega-3 fatty acid intake, and risk of pain: the Seniors-ENRICA-1 cohort

BACKGROUND & AIMS

Omega-3 fatty acids have anti-inflammatory and analgesic (anti-nociceptive) actions. However, the relation of habitual omega-3 fatty acid intake and fish consumption - its main food source - with pain remains largely unknown. We examined the association of fish consumption and marine omega-3 fatty acid intake with pain incidence and worsening over 5 years among older adults.

METHODS

Data were taken from the Seniors - ENRICA-1 cohort, which included 950 individuals aged ≥60 years in Spain. Habitual fish consumption and marine omega-3 fatty acid intake during the previous year were assessed in 2008-2010 and 2012 with a validated diet history. Pain was assessed in 2012 and 2017 with a scale developed from the Survey on Chronic Pain in Europe, ranging from 0 (no pain) to 6 (highest pain), according to its severity, frequency, and number of locations. Analyses on pain incidence were conducted in the 524 participants free of pain at baseline, while those on pain worsening were performed in the overall cohort, and both were adjusted for sociodemographic variables, lifestyle, morbidity, and diet quality.

RESULTS

Higher oily fish consumption was associated with reduced pain incidence and worsening over 5 years [fully adjusted odds ratios (95% confidence interval) = 0.68 (0.50,0.94) and 0.70 (0.55,0.88) for every 25 g/day increment (1.5 servings/week), respectively]. Total and white fish consumption were not associated with pain. Higher marine omega-3 fatty acid intake was inversely associated with pain worsening [odds ratio (95% confidence interval) per 0.5 g/day increment = 0.83 (0.72,0.96)]. The corresponding associations for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were 0.53 (0.33,0.87) and 0.73 (0.57,0.94).

CONCLUSIONS

In this cohort of Spanish older adults, increased oily fish consumption was inversely associated with pain incidence and worsening over 5 years, while higher marine omega-3 fatty acid intake (and that of EPA and DHA) was linked to less pain worsening.

Dietary Vitamin D Intake, Pain Incidence, and Pain Changes in Older Adults: The Seniors-ENRICA-1 Cohort

Background: Vitamin D plays a role in bone health, pain signaling, and inflammation. We examined the largely unknown relation of dietary vitamin D intake with pain incidence and pain changes over time in older adults. Methods: Data were taken from the Seniors-ENRICA-1 cohort, which included 950 individuals aged ≥60 years. Habitual vitamin D intake was assessed in 2012 with a validated diet history, and pain both in 2012 and 2017 with a scale ranging from 0 (no pain) to 6 (highest pain), according to its severity, frequency, and number of locations. Analyses on pain incidence and pain changes were performed in the 524 participants free of pain at baseline and the overall sample, respectively. Results: Higher dietary vitamin D intake was associated with lower 5-year pain incidence; the multivariable-adjusted odds ratio (95% confidence interval) was 0.88 (0.79,0.99) for every 1-µg/day increase in vitamin D intake, and 0.49 (0.28,0.88) for the highest (>3.52 µg/day) vs. lowest (<1.85 µg/day) tertile. Dietary vitamin D intake (highest vs. lowest tertile) was also associated with 5-year favorable pain changes: the multivariable-adjusted odds ratio of pain worsening vs. no change/pain improvement was 0.55 (0.36,0.86), and the β coefficient for changes in the pain scale was −0.56 (−1.03,−0.09). Similar results were found for pain severity, frequency, and number of pain locations. Conclusions: In an older adult population, where compliance with vitamin D intake recommendations was very low, a slightly increased dietary intake was associated with lower pain incidence and favorable pain changes over 5 years.

Relationship between diet and relative risk of pain in a cross-sectional analysis of the REGARDS longitudinal study

Aim: Determine if dietary patterns affect risk of pain. Methods: Data from 16,061 participants (55.4% females, 32.3% Black, age 65 ± 9 years) in the REGARDS study were categorized based on the adherence to previous dietary patterns reflecting the prevalent foods within each (convenience, alcohol/salads, plant-based, sweets/fats and 'Southern'). A modified Poisson regression model was used to determine whether dietary patterns were associated with relative risk (RR) of pain. Results: High adherence to 'Southern' dietary pattern was associated with a 41% (95% CI: 23, 61%) increase in RR of pain. High adherence to a plant-based dietary pattern showed a 22% (95% CI: 11, 31%) decrease in the RR of pain. Conclusion: Poor quality dietary patterns increase the RR of pain, while plant-based patterns lowered the RR. Diet patterns should be incorporated into medical history.

Diet/Nutrition: Ready to Transition from a Cancer Recurrence/Prevention Strategy to a Chronic Pain Management Modality for Cancer Survivors?

Evidence for the relationship between chronic pain and nutrition is mounting, and chronic pain following cancer is gaining recognition as a significant area for improving health care in the cancer survivorship population. This review explains why nutrition should be considered to be an important component in chronic pain management in cancer survivors by exploring relevant evidence from the literature and how to translate this knowledge into clinical practice. This review was built on relevant evidence from both human and pre-clinical studies identified in PubMed, Web of Science and Embase databases. Given the relationship between chronic pain, inflammation, and metabolism found in the literature, it is advised to look for a strategic dietary intervention in cancer survivors. Dietary interventions may result in weight loss, a healthy body weight, good diet quality, systemic inflammation, and immune system regulations, and a healthy gut microbiota environment, all of which may alter the pain-related pathways and mechanisms. In addition to being a cancer recurrence or prevention strategy, nutrition may become a chronic pain management modality for cancer survivors. Although additional research is needed before implementing nutrition as an evidence-based management modality for chronic pain in cancer survivors, it is already critical to counsel and inform this patient population about the importance of a healthy diet based on the data available so far.

Identifying the most important confounders when assessing the association between low-grade systemic inflammation and musculoskeletal pain: A modified Delphi study

Objective

The association between low-grade systemic inflammation and musculoskeletal pain may be influenced by multiple factors. However, little is known about the relative importance of these factors, and few studies account for them. This Delphi study aimed to reach consensus on the most important confounders which influence the association between low-grade systemic inflammation and musculoskeletal pain.

Methods

The panel consisted of 48 experts. In Round 1, the experts proposed what they believed were important confounders. In Round 2, the experts indicated for each confounder whether they believed it was important (yes/no). At least 50% of experts had to indicate the confounder was important to be considered in the final round. In Round 3, the experts rated the importance of each confounder on a 7-point Likert scale. Consensus was reached if ≥75% of the experts considered the factor either extremely or moderately important.

Results

In Round 1, 120 confounders were proposed, which were synthesized into 38 distinct factors. In Round 2, 33 confounders met the criterion to be considered important. In Round 3, consensus was reached for 14 confounders: acute illness/trauma, immune disease, medication use, endocrine, nutritional, or metabolic disease, other musculoskeletal conditions, age, handling of blood samples, sex, cancer, body composition, pregnancy, cardiovascular disease, physical activity, and pain characteristics.

Conclusions

These findings provide insight in the complexity of the association between low-grade systemic inflammation and musculoskeletal pain. Some factors currently listed as confounders may be re-classified as moderators or mediators as insights progress.

Diet, body weight and pain susceptibility - A systematic review of preclinical studies

Obesity has been associated with increased chronic pain susceptibility but causes are unclear. In this review, we systematize and analyze pain outcomes in rodent models of obesity as these can be important tools for mechanistic studies. Studies were identified using MEDLINE/PubMed and Scopus databases using the following search query: (((pain) OR (nociception)) AND (obesity)) AND (rat OR (mouse) OR (rodent))). From each eligible record we extracted the following data: species, strain, sex, pain/obesity model and main behavioral readouts. Out of 695 records 33 were selected for inclusion. 27 studies assessed nociception/acute pain and 17 studies assessed subacute or chronic pain. Overall genetic and dietary models overlapped in pain-related outcomes. Most acute pain studies reported either decreased or unaltered responses to noxious painful stimuli. However, decreased thresholds to mechanical innocuous stimuli, i.e. allodynia, were frequently reported. In most studies using subacute and chronic pain models, namely of subcutaneous inflammation, arthritis and perineural inflammation, decreased thresholds and/or prolonged pain manifestations were reported in obesity models. Strain comparisons and longitudinal observations indicate that genetic factors and the time course of the pathology might account for some of the discrepancies observed across studies. Two studies reported increased pain in animals subjected to high fat diet in the absence of weight gain. Pain-related outcomes in experimental models and clinical obesity are aligned indicating that the rodent can be an useful tool to study the interplay between diet, obesity and pain. In both cases weight gain might represent only a minor contribution to abnormal pain manifestation.

Diet can exert both analgesic and pronociceptive effects in acute and chronic pain models: a systematic review of preclinical studies

BACKGROUND

Although diet is an essential aspect of human health, the link between diet and pain is still not well understood. Preclinical animal research provides information to understand underlying mechanisms that allow identifying the needs for human research.

OBJECTIVES

This study aims to give a systematic overview of the current evidence from preclinical studies regarding the analgesic and pronociceptive effects of various diets in non-neuropathic, non-cancer, or non-visceral acute and chronic pain models.

STUDY DESIGN

A systematic Review.

SETTING

This study examined studies that investigate the analgesic and pronociceptive effects of various diets in non-neuropathic, non-cancer, or non-visceral acute and chronic pain models.

METHODS

This review was conducted following the PRISMA guidelines and was registered in PROSPERO with the registration number CRD42019133473. The certainty of evidence was examined by a modified GRADE approach.

RESULTS

After the screening process twenty-four eligible papers were included in this review. Nineteen studies examined acute pain, nine studies chronic inflammatory pain, and four studies assessed both acute and chronic pain models.

LIMITATIONS

Due to the heterogeneity of the included studies, a meta-analysis was not included in this study.

CONCLUSIONS

In animal models, excessive saturated, monounsaturated or omega-6 polyunsaturated fat ingestion and diets rich in fats and carbohydrates can decrease pain sensitivity in acute nociceptive pain, whereas it can induce mechanical allodynia and heat hyperalgesia in chronic inflammatory pain. Additionally, diets rich in anti-inflammatory ingredients, as well as a calorie-restricted diet can promote recovery from primary mechanical allodynia and heat hyperalgesia in chronic inflammatory pain.

An Omega-3-rich Anti-inflammatory Diet Improved Widespread Allodynia and Worsened Metabolic Outcomes in Adult Mice Exposed to Neonatal Maternal Separation

Inflammation plays a key role in the progression and maintenance of chronic pain, which impacts the lives of millions of Americans. Despite growing evidence that chronic pain can be improved by treating underlying inflammation, successful treatments are lacking and pharmaceutical interventions are limited due to drug side effects. Here we are testing whether a 'healthy human' diet (HHD), with or without anti-inflammatory components (HHAID), improves pain-like behaviors in a preclinical model of chronic widespread hypersensitivity induced by neonatal maternal separation (NMS). The HHD and HHAID are isocaloric and macronutrient-matched, have a low glycemic index, and fat content (35 kcal%) that is high in omega-3 fatty acids, while only the HHAID includes a combination of key anti-inflammatory compounds, at clinically relevant doses. Mice on these diets were compared to mice on a control diet with a macronutrient composition commonly used in rodents (20% protein, 70% carbohydrate, 10% fat). Our results demonstrate a benefit of the HHAID on pain-like behaviors in both male and female mice, despite increased caloric intake, adiposity, and weight gain. In female mice, HHAID specifically increased measures of metabolic syndrome and inflammation compared to the HHD and control diet groups. Male mice were susceptible to worsening metabolic measures on both the HHAID and HHD. This work highlights important sexual dimorphic outcomes related to early life stress exposure and dietary interventions, as well as a potential disconnect between improvements in pain-like behaviors and metabolic measures.

Can an anti-inflammatory diet be effective in preventing or treating viral respiratory diseases? A systematic narrative review

Respiratory Viruses infections (RVI) such as rhinovirus, coronavirus, influenza virus, and adenovirus affect the respiratory and the immune systems. The role of nutrition in the respiratory and immune systems has been studied in some studies, and its importance is undeniable. In addition, one of the key findings in this disease is high inflammation that affects almost all patients. This systematic narrative review aims to answer the question, "Can an anti-inflammatory diet be effective in preventing or treating viral respiratory diseases?" A systematic review search was used for the articles extraction. All studies published in English from 1999 to 2020 investigating dietary inflammatory conditions and RVI were included. Food items with anti-inflammatory properties were selected based on the definition of the dietary inflammatory index (DII). We used Google Scholar, Pub Med, Scopus, Web of Science, Springer, Science Direct, Directory of Open Access Journals, Elsevier, Taylor and Francis, ProQuest, EBSCO, MEDLINE, and SciELO databases for extracting articles. Keywords were restricted by DII. Based on DII, food items/nutrients are involved in inflammation, some of which have anti-inflammatory and some inflammatory properties. Some foods/nutrients, in addition to their anti-inflammatory properties, have antioxidant, antiviral, and immune-enhancing properties. Considering the immune system's involvement, increased inflammation, and involvement of the pulmonary system in RVI and the remarkable role of the anti-inflammatory foods for counteracting them, it is recommended to use a predominantly anti-inflammatory diet along with prevention/control and treatment protocols. An anti-inflammatory diet (based on DII) includes turmeric, ginger, garlic, onions, saffron, dietary vitamin C, vitamin D, zinc, and omega-3 are recommended to reduce infection symptoms and duration.

Effects of a Fat-Rich Diet on the Spontaneous Release of Acetylcholine in the Neuromuscular Junction of Mice

Western societies are facing a clear increase in the rate of obesity and overweight which are responsible for musculoskeletal pain. Some of the substances described in the environment of myofascial trigger points (MTrPs) are the same as those found in the skeletal muscle of obese people, such as cytokines. Furthermore, elevated neuromuscular neurotransmission has been associated with MTrPs. The main objective of this study is to assess whether obesity or overweight may be a facilitator of myofascial pain. The experiments were performed on male Swiss mice. One experimental group was given a typical “cafeteria” diet and another group a commercial high-fat diet for six weeks. Intramuscular adipocytes were assessed with Sudan III. The functional study was performed with electromyographic recording to determine the plaque noise and intracellular recording of miniature endplate potentials (MEPPs). The intake of a cafeteria diet showed the presence of more adipocytes in muscle tissue, but not with the fat-supplemented diet. Both experimental groups showed an increase in the plaque noise and an increase in the frequency of MEPPs that lasted several weeks after interrupting diets. In summary, the supply of a hypercaloric diet for six weeks in mice increases spontaneous neurotransmission, thus facilitating the development of MTrPs.

High-fat diet exacerbates postoperative pain and inflammation in a sex-dependent manner

Obesity is often associated with increased pain, but little is known about the effects of obesity and diet on postoperative pain. In this study, effects of diet and obesity were examined in the paw incision model, a preclinical model of postoperative pain. Long-Evans rats were fed high-fat diet (40% calories from butter fat) or low-fat normal chow. Male rats fed high-fat diet starting 6 weeks before incision (a diet previously shown to induce markers of obesity) had prolonged mechanical hypersensitivity and an overall increase in spontaneous pain in response to paw incision, compared with normal chow controls. Diet effects in females were minor. Removing high-fat diet for 2 weeks before incision reversed the diet effects on pain behaviors, although this was not enough time to reverse high-fat diet-induced weight gain. A shorter (1 week) exposure to high-fat diet before incision also increased pain behaviors in males, albeit to a lesser degree. The 6-week high-fat diet increased macrophage density as examined immunohistochemically in lumbar dorsal root ganglion even before paw incision, especially in males, and sensitized responses of peritoneal macrophages to lipopolysaccharide stimuli in vitro. The nerve regeneration marker growth-associated protein 43 (GAP43) in skin near the incision (day 4) was higher in the high-fat diet group, and wound healing was delayed. In summary, high-fat diet increased postoperative pain particularly in males, but some diet effects did not depend on weight gain. Even short-term dietary manipulations, that do not affect obesity, may enhance postoperative pain.

Psychosocial Issues and Lifestyle Changes for the Renal Patient

This article provides an overview of the psychosocial issues faced by those with renal disease. The article discusses the physiologic connection between anxiety, depression, and pain-symptoms commonly seen in renal disease and other chronic illnesses. The application of integrative medicine or nonallopathic medicine and its role in the management of anxiety, depression, and pain are presented. Also presented is evidence surrounding several frequently used nonallopathic modalities appropriate for incorporation into a comprehensive management regimen for renal patients to reduce symptom burden. The article concludes with a discussion on the role of palliative care in treatment decisions for renal patients.

Integrative Medicine for the Treatment of Persistent Pain

Integrative health modalities can provide useful tools in the management of persistent pain in the primary care setting. These modalities, such as acupuncture, mind-body medicine, diet and herbs, and movement strategies can be safely used and may provide patients with hope and empowerment. It is highly recommended that the patient work alongside trained professionals for a given modality and/or an interprofessional team.

Effects of a Standard American Diet and an anti-inflammatory diet in male and female mice

BACKGROUND

Obesity and chronic pain are prevalent concerns. Pain is frequently experienced in weight-bearing joints, but is common in other areas of the body as well, suggesting other factors. Poor diet often contributes to obesity and can directly influence the immune system. We have shown that poor diet prolongs recovery from inflammatory injury. Therefore, our goal was to determine whether poor-quality diet-induced consequences could be prevented or reversed by an anti-inflammatory diet (AID).

METHODS

A Standard American Diet (SAD) was developed to investigate the effects of poor diet on pain. The SAD includes amounts of refined sugar, carbohydrates and fats that better model the typical American diet, as compared to high-fat diets. We developed an AID to explore whether the effects of the SAD could reverse or whether the AID would enhance recovery prophylactically. The AID was developed using ingredients (epigallocatechin gallate, sulforaphane, resveratrol, curcumin and ginseng) with known anti-inflammatory properties. Following 15 weeks of diet [SAD, AID or regular (REG)] exposure, male and female mice underwent inflammatory injury, at which point some animals had their diets switched for the remainder of the study.

RESULTS

Animals who consumed the SAD showed longer recovery compared to the AID- and REG-fed animals. Animals switched off the SAD had faster recovery times, with AID-fed animals recovering as fast as REG-fed animals.

CONCLUSIONS

Poor diet prolonged recovery from inflammatory injury. Substitution of SAD with AID or REG promoted faster recovery. These findings suggest diet can be used as a non-pharmacological intervention following injury.

SIGNIFICANCE

Obesity may increase susceptibility to chronic pain often due to poor diet. Diet has potential to be used as treatment for pain. This study investigates the use of a novel translatable diet to act as a preventative (i.e. prior to surgery) or an intervention (i.e. following an injury).

Roles of ginsenosides in inflammasome activation

Inflammation is an innate immune response that protects the body from pathogens, toxins, and other dangers and is initiated by recognizing pathogen-associated molecular patterns or danger-associated molecular patterns by pattern-recognition receptors expressing on or in immune cells. Intracellular pattern-recognition receptors, including nucleotide-binding oligomerization domain-like receptors (NLRs), absent in melanoma 2, and cysteine aspartate–specific protease (caspase)-4/5/11 recognize various pathogen-associated molecular patterns and danger-associated molecular patterns and assemble protein complexes called “inflammasomes.” These complexes induce inflammatory responses by activating a downstream effector, caspase-1, leading to gasdermin D –mediated pyroptosis and the secretion of proinflammatory cytokines, such as interleukin (IL)-1β and IL-18. Ginsenosides are natural steroid glycosides and triterpene saponins found exclusively in the plant genus Panax. Various ginsenosides have been identified, and their abilities to regulate inflammatory responses have been evaluated. These studies have suggested a link between ginsenosides and inflammasome activation in inflammatory responses. Some types of ginsenosides, including Rh1, Rg3, Rb1, compound K, chikusetsu saponin IVa, Rg5, and Rg1, have been clearly demonstrated to inhibit inflammatory responses by suppressing the activation of various inflammasomes, including the NLRP3, NLRP1, and absent in melanoma 2 inflammasomes. Ginsenosides have also been shown to inhibit caspase-1 and to decrease the expression of IL-1β and IL-18. Given this body of evidence, the functional relationship between ginsenosides and inflammasome activation provides new insight into the understanding of the molecular mechanisms of ginsenoside-mediated antiinflammatory actions. This relationship also has applications regarding the development of antiinflammatory remedies by ginsenoside-mediated targeting of inflammasomes, which could be used to prevent and treat inflammatory diseases.

Tea Consumption and Health-Related Quality of Life in Older Adults

BACKGROUND

Although tea consumption has been reported to have various health benefits in humans, its association with health-related quality of life (HRQOL) has not been investigated directly. We aimed to examine the relationship between tea consumption and HRQOL among older Chinese adults.

METHODS

We analyzed community-based cross-sectional data of 5,557 older Chinese individuals aged 60 years or older who participated in the Weitang Geriatric Diseases study. Information on tea consumption and HRQOL assessed by the European Quality of Life-5 dimensions (EQ-5D) were collected by questionnaires. We estimated the relationship of tea consumption and the EQ-5D index score using linear regression models and the association between tea consumption and self-reported EQ-5D health problems using logistic regression models.

RESULTS

The EQ-5D index score was higher for habitual tea drinkers than their counterparts. In multivariate linear analyses controlling for socio-demographic conditions, health conditions, and lifestyle habits, the differences in ED-5D index score between individuals with and without tea drinking habits was 0.012 (95% confidence interval, 0.006-0.017). In multivariate logistic analyses, habitual tea drinking was inversely associated with reporting of problems in EQ-5D dimensions mobility (odds ration [OR], 0.44; 95% CI: 0.23-0.84); pain/discomfort (OR, 0.74; 95% CI: 0.61-0.90); and anxiety/depression (OR, 0.60; 95% CI: 0.38-0.97). These associations were more evident for black or oolong tea than green tea.

CONCLUSION

Habitual tea consumption was associated with better HRQOL in older adults.

Toxins, Toxicity, and Endotoxemia: A Historical and Clinical Perspective for Chiropractors

OBJECTIVE

The purpose of this commentary is to review the notion of toxicity in the context of chiropractic practice.

DISCUSSION

The belief that body toxicity is the cause of disease has been promoted for thousands of years. Prior to the emergence of the chiropractic profession, the medical profession embraced the notion that the body becomes "toxic," requiring detoxification interventions or surgery. The legacy of body toxicity within the chiropractic approach to patient care began with Daniel David Palmer. Today, some sectors within the medical and chiropractic professions continue to embrace the concept of body toxicity and the related need to engage in detoxifying treatments. The most common areas of focus for detoxification are the intestines and liver; however, the nature of the toxicity in these organs has yet to be defined or measured. In contrast, diet-induced systemic bacterial endotoxemia is a measureable state that is known to be promoted by a diet rich in sugar, flour, and refined oil. This suggests that bacterial endotoxin may be a candidate toxin to consider in the clinical context, as many common conditions, such as obesity, metabolic syndrome, diabetes, interstitial cystitis, depression, and migraine headache, are known to be promoted by endotoxemia.

CONCLUSION

A diet rich in refined sugar, flour, and oils may induce proinflammatory changes within intestinal microbiota that lead to systemic, low-grade endotoxemia, which is a common variety of "toxicity" that is measurable and worthy of research consideration. Introducing a diet to reduce endotoxemia, rather than attempting to target a specific organ, appears to be a rational clinical approach for addressing the issue of toxicity.

Changes in Prevalence, Outcomes, and Help-seeking Behavior of Chronic Pain in an Aging Population Over the Last Decade

BACKGROUND

Chronic pain is expected to increase as the population ages. This study aimed to investigate the changes in prevalence, patterns, and help-seeking behavior of chronic pain and prevalence of neuropathic pain of an aging population in Hong Kong.

METHODS

A cross-sectional, telephone interview with a structured questionnaire was conducted in a randomly selected sample of adults with acute or chronic pain of any kind in the general population to estimate the prevalence of chronic and neuropathic pain, and to describe sociodemographics and help-seeking behavior. Results were compared with a similar study conducted in 1999.

RESULTS

Totally, 1,570 people were interviewed. Chronic pain was experienced by 28.7% of all respondents, compared to 10.8% in 1999. Joint (45.5%), muscle (27.1%), and back (25.2%) pain were the most common, similar to findings in 1999. Of those with chronic pain, 83.1% reported pain in more than one body site (63.4% in 1999, P = 0.0023). More respondents reported their average pain as being intense (51.57% vs. 33.0% in 2013 and 1999, respectively, P = 0.0098). A downward trend of respondents taking medications for chronic pain (34.9% in 2013 vs. 47.6% in 1999, P = 0.019) was seen. Neuropathic pain was present in 9.03% of the population and 14.7% of chronic pain sufferers.

CONCLUSION

The prevalence of neuropathic pain in Hong Kong is high and is described here for the first time. The number of chronic pain sufferers has tripled in the past decade. Significant changes in the patterns and help- seeking behavior of chronic pain sufferers are also seen.

Total Western Diet Alters Mechanical and Thermal Sensitivity and Prolongs Hypersensitivity Following Complete Freund's Adjuvant in Mice

Obesity and chronic pain are often comorbid and their rates are increasing. It is unknown whether increased pain is caused by greater weight or poor diet quality or both. Therefore, we utilized a Total Western Diet (TWD) to investigate the functional and physiologic consequences of nutritionally poor diet in mice. For 13 weeks on the commercially available TWD, based on the National Health and Nutrition Examination Survey, thresholds of TWD-fed mice significantly increased in both thermal and mechanical tests. Quantitative magnetic resonance imaging revealed a significant increase in fat mass with a concomitant decrease in lean mass in the TWD-fed mice. In addition, there were significant increases in levels of serum leptin and inflammatory cytokines. After chronic pain induction using complete Freund's adjuvant, hypersensitivity was more pronounced and significantly prolonged in the TWD-fed mice. Therefore, prolonged exposure to poor diet quality resulted in altered acute nociceptive sensitivity, systemic inflammation, and persistent pain after inflammatory pain induction.

PERSPECTIVE

These results highlight the negative effects of poor diet quality with respect to recovery from hypersensitivity and susceptibility to chronic pain. A complete understanding of the impact of diet can aid in treatment and recovery dynamics in human clinical patients.