Mitochondrial dysfunction and mitophagy activation in blood mononuclear cells of fibromyalgia patients: implications in the pathogenesis of the disease

Role of mitochondrial dysfunction and biogenesis in fibromyalgia syndrome: Molecular mechanism in central nervous system

A critical role for mitochondrial dysfunction has been shown in the pathogenesis of fibromyalgia. It is a chronic pain syndrome characterized by neuroinflammation and impaired oxidative balance in the central nervous system. Boswellia serrata (BS), a natural polyphenol, is a well-known able to influence the mitochondrial metabolism. The objective of this study was to evaluate the mitochondrial dysfunction and biogenesis in fibromyalgia and their modulation by BS. To induce the model reserpine (1 mg/Kg) was subcutaneously administered for three consecutive days and BS (100 mg/Kg) was given orally for twenty-one days. BS reduced pain like behaviors in reserpine-injected rats and the astrocytes activation in the dorsal horn of the spinal cord and prefrontal cortex that are recognized as key regions associated with the neuropathic pain. Vulnerability to neuroinflammation and impaired neuronal plasticity have been described as consequences of mitochondrial dysfunction. BS administration increased PGC-1α expression in the nucleus of spinal cord and brain tissues, promoting the expression of regulatory genes for mitochondrial biogenesis (NRF-1, Tfam and UCP2) and cellular antioxidant defence mechanisms (catalase, SOD2 and Prdx 3). According with these data BS reduced lipid peroxidation and the GSSG/GSH ratio and increased SOD activity in the same tissues. Our results also showed that BS administration mitigates cytochrome-c leakage by promoting mitochondrial function and supported the movement of PGC-1α protein into the nucleus restoring the quality control of mitochondria. Additionally, BS reduced Drp1 and Fis1, preventing both mitochondrial fission and cell death, and increased the expression of Mfn2 protein, facilitating mitochondrial fusion. Overall, our results showed important mitochondrial dysfunction in central nervous system in fibromyalgia syndrome and the role of BS in restoring mitochondrial dynamics.

Schwann cell TRPA1 elicits reserpine-induced fibromyalgia pain in mice

BACKGROUND AND PURPOSE

Fibromyalgia is a complex clinical disorder with an unknown aetiology, characterized by generalized pain and co-morbid symptoms such as anxiety and depression. An imbalance of oxidants and antioxidants is proposed to play a pivotal role in the pathogenesis of fibromyalgia symptoms. However, the precise mechanisms by which oxidative stress contributes to fibromyalgia-induced pain remain unclear. The transient receptor potential ankyrin 1 (TRPA1) channel, known as both a pain sensor and an oxidative stress sensor, has been implicated in various painful conditions.

EXPERIMENTAL APPROACH

The feed-forward mechanism that implicates reactive oxygen species (ROS) driven by TRPA1 was investigated in a reserpine-induced fibromyalgia model in C57BL/6J mice employing pharmacological interventions and genetic approaches.

KEY RESULTS

Reserpine-treated mice developed pain-like behaviours (mechanical/cold hypersensitivity) and early anxiety-depressive-like disorders, accompanied by increased levels of oxidative stress markers in the sciatic nerve tissues. These effects were not observed upon pharmacological blockade or global genetic deletion of the TRPA1 channel and macrophage depletion. Furthermore, we demonstrated that selective silencing of TRPA1 in Schwann cells reduced reserpine-induced neuroinflammation (NADPH oxidase 1-dependent ROS generation and macrophage increase in the sciatic nerve) and attenuated fibromyalgia-like behaviours.

CONCLUSION AND IMPLICATIONS

Activated Schwann cells expressing TRPA1 promote an intracellular pathway culminating in the release of ROS and recruitment of macrophages in the mouse sciatic nerve. These cellular and molecular events sustain mechanical and cold hypersensitivity in the reserpine-evoked fibromyalgia model. Targeting TRPA1 channels on Schwann cells could offer a novel therapeutic approach for managing fibromyalgia-related behaviours.

Bioenergetic profiles of peripheral mononuclear cells and systemic inflammation in women with Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS)

Inflammation is thought to contribute to the etiology of interstitial cystitis/bladder pain syndrome (IC/BPS). It is well-known that disruption in metabolism in immune cells contributes to inflammation in several inflammatory diseases. The purpose of this study was to investigate whether cellular bioenergetics is altered in monocytes and lymphocytes from women with IC/BPS, and if these alterations correlate with systemic inflammatory markers. Age and BMI matched adult healthy women (HS; n = 18) and women with IC/BPS (n = 18) were included in the study. Blood was collected to assess cellular bioenergetics in monocytes and lymphocytes using a Seahorse XF96 Analyzer and plasma cytokine levels were measured using Meso Scale Discovery immunoassays. The correlation between bioenergetic parameters, cytokines, and demographics was determined using Pearson correlation coefficients. Means of the two groups were compared using the two-group t-test. Patients with IC/BPS had reduced monocyte oxygen consumption rates and glycolytic rates compared to healthy subjects. In contrast, lymphocytes from these patients had increased oxygen consumption rates and glycolytic rates. Several cytokines and chemokines including Interferon-gamma (IFN-ɣ), tumor necrosis factor alpha (TNF-ɑ), Interleukin-6 (IL-6), Interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF) levels were significantly elevated in the plasma of patients with IC/BPS. However, Transforming growth factor (TGF-β) and Interleukin-10 (IL-10) levels were significantly decreased in IC/BPS patients compared to HS. In addition, Interferon gamma (IFN-ɣ), TNF-ɑ, IL-8, and TGF-β levels correlated with several bioenergetic parameters in monocytes or lymphocytes from healthy subjects. In contrast, TNF-ɑ and IL-8 correlated with bioenergetic parameters in monocytes from IC/BPS patients. Monocyte and lymphocyte cellular bioenergetics and plasma cytokine levels are different in patients with IC/PBS compared to HS. It appears that systemic inflammation is greater in this cohort which may negatively impact immune cell function. The relationship between cellular bioenergetics and inflammation in monocytes and lymphocytes could be important in understanding the pathogenesis of IC/PBS and warrants further investigation.

Study protocol for FIBROKIT: a new tool for fibromyalgia diagnosis and patient follow-up

Fibromyalgia (FM) is a complex disease that is characterized by chronic musculoskeletal pain and has great economic impact. FM prevalence is about 2% to 4% worldwide, affecting mainly middle-aged women, and its complex pathophysiology complicates diagnosis, treatment and the findings of solid biomarkers. Previous studies have suggested an association between the disease and oxidative stress, mitochondrial metabolism, intestinal microbiota and inflammation, providing sufficient data to support the multifactorial origin of FM. Hence, the objective of this randomized, prospective, low-interventional, double-blinded and placebo-controlled clinical trial is the development of a specific panel of FM biomarkers and the evaluation of their response to a six-month nutritional intervention based on the Mediterranean diet supplemented with extra virgin olive oil (EVOO). For this purpose, the experimental design implies the recruitment of a large cohort of female Spanish patients. Middle-aged women who meet the diagnostic criteria for FM according to the American College of Rheumatology (ACR) will be eligible, along with age-matched healthy women. Both groups will be randomly divided into placebo (olive oil, OO) and treatment groups (extra virgin olive oil, EVOO), and will provide samples at the beginning (T0), after 3 months of nutritional intervention (T1), at the end of the nutritional intervention in 6 months (T2), and 6 months after the end of nutritional intervention (TF), being enrolled for 1 year. Data will be collected through health questionnaires, and whole blood and stool samples will be taken and analyzed. Blood will be used for western-blotting and proteomic analysis of mitochondrial homeostasis and plasma proteome, while stool will undergo metagenomic analysis, respectively. This study represents the first low-interventional investigation with more than 200 participants focused on exploring the association of oxidative stress, mitochondrial metabolism, intestinal microbiota and related pathways with a nutritional intervention in the context of FM. As a result, the outcomes of this study will significantly contribute to the development of a comprehensive and robust panel of diagnostic biomarkers, and will shed some light on their modulation with non-pharmacological therapies such as nutrition. Clinical trial registration: https://clinicaltrials.gov/study/NCT05921409, identifier: NCT05921409.

Microbiota and Mitochondrial Sex-Dependent Imbalance in Fibromyalgia: A Pilot Descriptive Study

Fibromyalgia is a widespread chronic condition characterized by pain and fatigue. Among the long list of physiological disturbances linked to this syndrome, mitochondrial imbalance and oxidative stress stand out. Recently, the crosstalk between mitochondria and intestinal microbiota has caught the attention of biomedical researchers, who have found connections between this axis and several inflammatory and pain-related conditions. Hence, this pilot descriptive study focused on characterizing the mitochondrial mass/mitophagy ratio and total antioxidant capacity in PBMCs, as well as some microbiota components in feces, from a Peruvian cohort of 19 females and 7 males with FM. Through Western blotting, electrochemical oxidation, ELISA, and real-time qPCR, we determined VDAC1 and MALPLC3B protein levels; total antioxidant capacity; secretory immunoglobulin A (sIgA) levels; and Firmicutes/Bacteroidetes, Bacteroides/Prevotella, and Roseburia/Eubacterium ratios; as well as Ruminococcus spp., Pseudomonas spp., and Akkermansia muciniphila levels, respectively. We found statistically significant differences in Ruminococcus spp. and Pseudomonas spp. levels between females and males, as well as a marked polarization in mitochondrial mass in both groups. Taken together, our results point to a mitochondrial imbalance in FM patients, as well as a sex-dependent difference in intestinal microbiota composition.

Cardiac output and arteriovenous oxygen difference contribute to lower peak oxygen uptake in patients with fibromyalgia

BACKGROUND

Patients with fibromyalgia (FM) exhibit low peak oxygen uptake ([Formula: see text]O_2peak). We aimed to detect the contribution of cardiac output to ([Formula: see text]) and arteriovenous oxygen difference [Formula: see text] to [Formula: see text] from rest to peak exercise in patients with FM.

METHODS

Thirty-five women with FM, aged 23 to 65 years, and 23 healthy controls performed a step incremental cycle ergometer test until volitional fatigue. Alveolar gas exchange and pulmonary ventilation were measured breath-by-breath and adjusted for fat-free body mass (FFM) where appropriate. [Formula: see text] (impedance cardiography) was monitored. [Formula: see text] was calculated using Fick's equation. Linear regression slopes for oxygen cost (∆[Formula: see text]O₂/∆work rate) and [Formula: see text] to [Formula: see text]O₂ (∆[Formula: see text]/∆[Formula: see text]O₂) were calculated. Normally distributed data were reported as mean ± SD and non-normal data as median [interquartile range].

RESULTS

[Formula: see text]O_2peak was lower in FM patients than in controls (22.2 ± 5.1 vs. 31.1 ± 7.9 mL∙min^-1∙kg^-1, P < 0.001; 35.7 ± 7.1 vs. 44.0 ± 8.6 mL∙min^-1∙kg FFM^-1, P < 0.001). [Formula: see text] and C(a-v)O₂ were similar between groups at submaximal work rates, but peak [Formula: see text] (14.17 [13.34-16.03] vs. 16.06 [15.24-16.99] L∙min^-1, P = 0.005) and C(a-v)O₂ (11.6 ± 2.7 vs. 13.3 ± 3.1 mL O₂∙100 mL blood^-1, P = 0.031) were lower in the FM group. No significant group differences emerged in ∆[Formula: see text]O₂/∆work rate (11.1 vs. 10.8 mL∙min^-1∙W^-1, P = 0.248) or ∆[Formula: see text]/∆[Formula: see text]O₂ (6.58 vs. 5.75, P = 0.122) slopes.

CONCLUSIONS

Both [Formula: see text] and C(a-v)O₂ contribute to lower [Formula: see text]O_2peak in FM. The exercise responses were normal and not suggestive of a muscle metabolism pathology.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03300635. Registered 3 October 2017-Retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT03300635 .

Global Impacts of Western Diet and Its Effects on Metabolism and Health: A Narrative Review

The Western diet is a modern dietary pattern characterized by high intakes of pre-packaged foods, refined grains, red meat, processed meat, high-sugar drinks, candy, sweets, fried foods, conventionally raised animal products, high-fat dairy products, and high-fructose products. The present review aims to describe the effect of the Western pattern diet on the metabolism, inflammation, and antioxidant status; the impact on gut microbiota and mitochondrial fitness; the effect of on cardiovascular health, mental health, and cancer; and the sanitary cost of the Western diet. To achieve this goal, a consensus critical review was conducted using primary sources, such as scientific articles, and secondary sources, including bibliographic indexes, databases, and web pages. Scopus, Embase, Science Direct, Sports Discuss, ResearchGate, and the Web of Science were used to complete the assignment. MeSH-compliant keywords such "Western diet", "inflammation", "metabolic health", "metabolic fitness", "heart disease", "cancer", "oxidative stress", "mental health", and "metabolism" were used. The following exclusion criteria were applied: (i) studies with inappropriate or irrelevant topics, not germane to the review's primary focus; (ii) Ph.D. dissertations, proceedings of conferences, and unpublished studies. This information will allow for a better comprehension of this nutritional behavior and its effect on an individual's metabolism and health, as well as the impact on national sanitary systems. Finally, practical applications derived from this information are made.

Nutrient Therapy for the Improvement of Fatigue Symptoms

Fatigue, characterised by lack of energy, mental exhaustion and poor muscle endurance which do not recover following a period of rest, is a common characteristic symptom of several conditions and negatively impacts the quality of life of those affected. Fatigue is often a symptom of concern for people suffering from conditions such as fibromyalgia, chronic fatigue syndrome, cancer, and multiple sclerosis. Vitamins and minerals, playing essential roles in a variety of basic metabolic pathways that support fundamental cellular functions, may be important in mitigating physical and mental fatigue. Several studies have examined the potential benefits of nutrients on fatigue in various populations. The current review aimed to gather the existing literature exploring different nutrients' effects on fatigue. From the searches of the literature conducted in PubMed, Ovid, Web of Science, and Google scholar, 60 articles met the inclusion criteria and were included in the review. Among the included studies, 50 showed significant beneficial effects (p < 0.05) of vitamin and mineral supplementation on fatigue. Altogether, the included studies investigated oral or parenteral administration of nutrients including Coenzyme Q10, L-carnitine, zinc, methionine, nicotinamide adenine dinucleotide (NAD), and vitamins C, D and B. In conclusion, the results of the literature review suggest that these nutrients have potentially significant benefits in reducing fatigue in healthy individuals as well as those with chronic illness, both when taken orally and parenterally. Further studies should explore these novel therapies, both as adjunctive treatments and as sole interventions.

Could the fibromyalgia syndrome be triggered or enhanced by COVID-19?

Fibromyalgia (FM) is a complex disease with an uncertain aetiology and intricate pathophysiology. Although its genesis is not fully explained, potential environmental factors, such as viral infections might trigger FM or worsen patients' clinical outcomes. The SARS-CoV-2 virus may affect central and peripheral nervous systems, leading to musculoskeletal, neurological, and psychological disturbances. These symptoms might persist at least 12 months beyond the recovery, often referred to as post-COVID syndrome, which resembles FM syndrome. In this sense, we argued the potential consequences of COVID-19 exclusively on FM syndrome. First, we have described post-COVID syndrome and its painful symptoms. Afterwards, we argued whether FM syndrome could be triggered or enhanced by COVID-19 infection or by numerous and persistent stressors imposed daily by the pandemic setting (isolation, uncertainty, depression, mental stress, generalized anxiety, and fear of the virus). In addition, we have demonstrated similarities between pathophysiological mechanisms and cardinal symptoms of FM and COVID-19, speculating that SARS-CoV-2 might represent a critical mediator of FM or an exacerbator of its symptoms once both syndromes share similar mechanisms and complaints. Therefore, pharmacologic and non-pharmacological approaches commonly used to treat FM could serve as strategic therapies to attenuate painful and neurological manifestations of post-COVID syndrome. Although it is still theoretical, clinicians and researchers should be alert of patients who develop symptoms similar to FM or those who had their FM symptoms increased post-COVID to manage them better.

Is Disrupted Mitophagy a Central Player to Parkinson's Disease Pathology?

Whilst the pathophysiology at a cellular level has been defined, the cause of Parkinson's disease (PD) remains poorly understood. This neurodegenerative disorder is associated with impaired dopamine transmission in the substantia nigra, and protein accumulations known as Lewy bodies are visible in affected neurons. Cell culture models of PD have indicated impaired mitochondrial function, so the focus of this paper is on the quality control processes involved in and around mitochondria. Mitochondrial autophagy (mitophagy) is the process through which defective mitochondria are removed from the cell by internalisation into autophagosomes which fuse with a lysosome. This process involves many proteins, notably including PINK1 and parkin, both of which are known to be coded on genes associated with PD. Normally in healthy individuals, PINK1 associates with the outer mitochondrial membrane, which then recruits parkin, activating it to attach ubiquitin proteins to the mitochondrial membrane. PINK1, parkin, and ubiquitin cooperate to form a positive feedback system which accelerates the deposition of ubiquitin on dysfunctional mitochondria, resulting in mitophagy. However, in hereditary PD, the genes encoding PINK1 and parkin are mutated, resulting in proteins that are less efficient at removing poorly performing mitochondria, leaving cells more vulnerable to oxidative stress and ubiquitinated inclusion bodies, such as Lewy bodies. Current research that looks into the connection between mitophagy and PD is promising, already yielding potentially therapeutic compounds; until now, pharmacological support for the mitophagy process has not been part of the therapeutic arsenal. Continued research in this area is warranted.

Acute Effects of a Session with The EXOPULSE Mollii Suit in a Fibromyalgia Patient: A Case Report

Fibromyalgia is a chronic disorder characterized by widespread musculoskeletal pain and associated fatigue, sleep disturbances, and other cognitive and somatic symptoms. A multidisciplinary approach including pharmacological therapies along with behavioral therapy, exercise, patient education, and pain management is a possible solution for the treatment of this disease. The EXOPULSE Mollii^® method (EXONEURAL NETWORK AB, Danderyd, Sweden) is an innovative approach for non-invasive and self-administered electrical stimulation with multiple electrodes incorporated in a full-body suit, with already proven benefits for other diseases. Therefore, the present case report study aims to evaluate the effects that a 60 min session with the EXOPULSE Mollii suit has on a female fibromyalgia patient. After the intervention, we can conclude that a 60 min session with the EXOPULSE Mollii suit has beneficial effects on pain perception, muscle oxygenation, parasympathetic modulation, and function in a female fibromyalgia patient.

The Behavior of Muscle Oxygen Saturation, Oxy and Deoxy Hemoglobin during a Fatigue Test in Fibromyalgia

Previous studies have reported that people with fibromyalgia (FM) could suffer from mitochondrial dysfunction. However, the consumption of muscle oxygen during physical exercise has been poorly studied. Therefore, this study aimed to explore the response of muscle oxygen during a fatigue protocol in people with FM and healthy controls (HC). In addition, the peak torque and the total work were assessed. A total of 31 participants (eighteen were people with fibromyalgia and thirteen were healthy controls) were enrolled in this cross-sectional study. All the participants underwent a fatigue protocol consisting of 20 repetitions at 180°·s−1 of quadriceps flexions and extensions using a Biodex System 3. The muscle oxygen saturation (SmO2), total hemoglobin (THb), deoxygenated hemoglobin (HHb) and oxygenated hemoglobin (O2Hb) values were measured using a portable near-infrared spectroscopy (NIRS) device. Significant differences between people with FM and healthy controls were found at baseline: SmO2 (FM: 56.03 ± 21.36; HC: 77.41 ± 10.82; p = 0.036), O2Hb (FM: 6.69 ± 2.59; HC: 9.37 ± 1.31; p = 0.030) and HHb (FM: 5.20 ± 2.51; HC: 2.73 ± 1.32; p = 0.039); during the fatigue protocol: SmO2 (FM: 48.54 ± 19.96; HC: 58.87 ± 19.72; p = 0.038), O2Hb (FM: 5.70 ± 2.34; HC: 7.06 ± 2.09; p = 0.027) and HHb (FM: 5.69 ± 2.65; HC: 4.81 ± 2.39; p = 0.048); and in the recovery at three min and six min for SmO2, O2Hb and HHb (p < 0.005). Furthermore, healthy control values of SmO2, O2Hb and HHb have been significantly altered by the fatigue protocol (p < 0.005). In contrast, people with FM did not show any significant alteration in these values. Moreover, significant differences were found in the peak torque at extension (FM: 62.48 ± 24.45; HC: 88.31 ± 23.51; p = 0.033) and flexion (FM: 24.16 ± 11.58; HC: 42.05 ± 9.85; p = 0.010), and the total work performed at leg extension (FM: 1039.78 ± 434.51; HC: 1535.61 ± 474.22; p = 0.007) and flexion (FM: 423.79 ± 239.89; HC: 797.16 ± 194.37; p = 0.005).

Age-related mechanisms in the context of rheumatic disease

Ageing is characterized by a progressive loss of cellular function that leads to a decline in tissue homeostasis, increased vulnerability and adverse health outcomes. Important advances in ageing research have now identified a set of nine candidate hallmarks that are generally considered to contribute to the ageing process and that together determine the ageing phenotype, which is the clinical manifestation of age-related dysfunction in chronic diseases. Although most rheumatic diseases are not yet considered to be age related, available evidence increasingly emphasizes the prevalence of ageing hallmarks in these chronic diseases. On the basis of the current evidence relating to the molecular and cellular ageing pathways involved in rheumatic diseases, we propose that these diseases share a number of features that are observed in ageing, and that they can therefore be considered to be diseases of premature or accelerated ageing. Although more data are needed to clarify whether accelerated ageing drives the development of rheumatic diseases or whether it results from the chronic inflammatory environment, central components of age-related pathways are currently being targeted in clinical trials and may provide a new avenue of therapeutic intervention for patients with rheumatic diseases.

Oxidative Stress in Fibromyalgia: From Pathology to Treatment

Fibromyalgia (FM) is characterized by chronic widespread musculoskeletal pain associated with sleep problems, fatigue, depression, and anxiety. The persistence of pain, impairment of cognitive function, and negative impact on the psychological state have caused a detrimental effect on the patients' quality of life. However, to date, the treatment and mechanisms of this disease are yet to be established. Oxidative stress might play a critical role in FM pathophysiology. Increased levels of prooxidative factors such as nitric oxide, lipid peroxidation, and mitophagy can cause pain sensitization in fibromyalgia. Numerous studies have supported the hypothesis of beneficial antioxidative effects in FM. Due to the lack of effective therapy for fibromyalgia, many treatments are sought to reduce pain and fatigue and improve patients' quality of life. This manuscript discusses the impact of various antioxidative procedures that can diminish fibromyalgia symptoms, such as hyperbaric oxygen therapy, modification of dietary habits, and physical activity.

The Use of the Coenzyme Q10 as a Food Supplement in the Management of Fibromyalgia: A Critical Review

The coenzyme Q₁₀ is a naturally occurring benzoquinone derivative widely prescribed as a food supplement for different physical conditions and pathologies. This review aims to sum up the key structural and functional characteristics of Q₁₀, taking stock of its use in people affected by fibromyalgia. A thorough survey has been conducted, using Pubmed, Scifinder, and ClinicalTrials.gov as the reference research applications and registry database, respectively. Original articles, reviews, and editorials published within the last 15 years, as well as open clinical investigations in the field, if any, were analyzed to point out the lights and shadows of this kind of supplementation as they emerge from the literature.

Integrated metabolomics revealed the fibromyalgia-alleviation effect of Mo2C nanozyme through regulated homeostasis of oxidative stress and energy metabolism

Fibromyalgia (FM), the most common cause of chronic musculoskeletal pain in the general public, lacks advanced therapeutic methodology and detailed bioinformation. However, acting as a newly developed and important transition metal carbide or carbonitride, the Mo2C nanozyme has provided a novel iatrotechnique with excellent bioactivity in a cell/animal model, which also exhibits potential prospects for future clinical applications. In addition, high-content and high-throughput integrated metabolomics (including aqueous metabolomics, lipidomics, and desorption electrospray ionization-mass spectrometry imaging) also specializes in qualitative and quantitative analysis of metabolic shifts at the molecular level. In this work, the FM-alleviation effect of Mo2C nanozyme was investigated through integrated metabolomics in a mouse model. An advanced platform combining gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry and bioinformatics was utilized to study the variation in the mouse metabolome and lipidome. The results revealed that Mo2C treatment could effectively enhance energy metabolism-related biological events impaired by FM, leading to homeostasis of oxidative stress and energy metabolism toward the control levels. During this process, Mo2C facilitated the elimination of ROS in plasma and cells and the rehabilitation of mice from oxidative stress and mitochondrial dysfunction. It was believed that such an integrated metabolomics study on the FM-alleviation effect of Mo2C nanozyme could provide another excellent alternative to traditional Mo2C-based research with numerous pieces of bioinformation, further supporting research area innovation, material modification, and clinical application.

Oxidative Stress Biomarkers and Quality of Life Are Contributing Factors of Muscle Pain and Lean Body Mass in Patients with Fibromyalgia

Simple Summary

Fibromyalgia (FM) is a disease that primarily affects women and causes pain all over the body, as well as anxiety, depression, fatigue, weight gain, a decreased quality of life, and difficulties doing daily duties. Although the cause of this disease has yet to be identified, research have been completed or are under underway with the goal of uncovering clues that can explain the disease’s symptoms and proper treatment. Our research looked into whether factors that increase inflammation in the body cause disease symptoms to worsen. Pain, lean mass, quality of life, sleep quality, muscle strength, depression, and probable factors that cause these symptoms to aggravate were assessed in the blood. Women with FM with more pain had a lower quality of life, and women with FM with lower lean mass had muscle weakness in addition to a lower quality of life. Our results recommend that initiatives be implemented to reduce inflammation, improve muscle mass and strength gain and increase the quality of life of these women.

Abstract

(1) The evidence points to an increase in oxygen reactive species as one of the possible causes of fibromyalgia (FM). In addition, it is plausible that an imbalance in redox markers can be associated with pain amplification and dynapenia in FM patients. The aim of our study was to investigate possible factors associated with muscle pain and lean body mass in FM patients. (2) Methods: This was a quantitative, exploratory and cross-sectional study of 47 patients with FM (53.45 + 7.32 years). We evaluated self-perceptions of muscle pain, lean body mass, body composition, quality of life, sleep quality, depression index, muscle performance and oxidative stress biomarkers. (3) Results: We observed that lower blood levels of antioxidants and poor quality of life explained 21% of the greater muscle pain. In addition, high blood levels of oxidative stress, worse muscle performance and poor quality of life explained 27% of the lower lean mass in patients with FM. (4) Conclusions: Larger amounts of lipid peroxidation and reductions in antioxidant levels, in addition to lower muscle performance and poor life quality, are possible independent contributors to greater muscle pain and lower lean body mass in FM patients.

Cytokine profile and cholesterol levels in patients with Niemann-Pick type C disease presenting neurological symptoms: The in vivo effect of miglustat and the in vitro effect of N-acetylcysteine and Coenzyme Q10

Niemann Pick type C is an inborn error of metabolism (IEM), classified as a lysosomal storage disease (LSD) caused by a dysfunction in NPC transport protein, that leads to intracellular accumulation of non-esterified cholesterol and other lipids. Clinical manifestations are ample, with visceral and neurological symptoms. Miglustat, a molecule that reversibly inhibits glucosylceramide synthase is used as treatment for this disorder. Studies demonstrated the influence of oxidative stress and inflammation in IEM, as well in animal model of NP-C disease. Nonetheless, literature lacks data on patients, so our work aimed to investigate if there is influence of chronic inflammation in the pathophysiology of NP-C disease, and the effect of miglustat, N-acetylcysteine (NAC) and Coenzyme Q10 (CoQ10). We evaluated the plasmatic cytokines in NPC patients at diagnosis and during the treatment with miglustat. Additionally, we performed an in vitro study with antioxidants NAC (1 mM and 2.5 mM) and CoQ10 (5 μM and 10 μM), where we could verify its effect on inflammatory parameters, as well as in cholesterol accumulation. Our results showed that NP-C patients have higher plasmatic levels of pro and anti-inflammatory cytokines (IL-6, IL-8, and IL-10) at diagnosis and the treatment with miglustat was able to restore it. In vitro study showed that treatment with antioxidants in higher concentrations significantly decrease cholesterol accumulation, and NAC at 2.5 mM normalized the level of pro-inflammatory cytokines. Although the mechanism is not completely clear, it can be related to restoration in lipid traffic and decrease in oxidative stress caused by antioxidants.

Assessment of mitochondrial respiratory capacity using minimally invasive and noninvasive techniques in persons with spinal cord injury

Purpose

Muscle biopsies are the gold standard to assess mitochondrial respiration; however, biopsies are not always a feasible approach in persons with spinal cord injury (SCI). Peripheral blood mononuclear cells (PBMCs) and near-infrared spectroscopy (NIRS) may alternatively be predictive of mitochondrial respiration. The purpose of the study was to evaluate whether mitochondrial respiration of PBMCs and NIRS are predictive of respiration of permeabilized muscle fibers after SCI.

Methods

Twenty-two individuals with chronic complete and incomplete motor SCI between 18–65 years old were recruited to participate in the current trial. Using high-resolution respirometry, mitochondrial respiratory capacity was measured for PBMCs and muscle fibers of the vastus lateralis oxidizing complex I, II, and IV substrates. NIRS was used to assess mitochondrial capacity of the vastus lateralis with serial cuff occlusions and electrical stimulation.

Results

Positive relationships were observed between PBMC and permeabilized muscle fibers for mitochondrial complex IV (r = 0.86, P < 0.0001). Bland-Altman displayed agreement for complex IV (MD = 0.18, LOA = -0.86 to 1.21), between PBMCs and permeabilized muscles fibers. No significant relationships were observed between NIRS mitochondrial capacity and respiration in permeabilized muscle fibers.

Conclusions

This is the first study to explore and support the agreement of less invasive clinical techniques for assessing mitochondrial respiratory capacity in individuals with SCI. The findings will assist in the application of PBMCs as a viable alternative for assessing mitochondrial health in persons with SCI in future clinical studies.

Evaluation of Endothelial Dysfunction and Autophagy in Fibromyalgia-Related Vascular and Cerebral Cortical Changes and the Ameliorative Effect of Fisetin

Fibromyalgia (FM) is a common chronic pain syndrome that affects 1% to 5% of the population. We aimed to investigate the role of endothelial dysfunction and autophagy in fibromyalgia-related vascular and cerebral cortical changes in a reserpine-induced rat model of fibromyalgia at the histological and molecular levels and to study the ameliorative effect of fisetin. Forty adult female albino rats were divided into four groups (10 each): two control groups, the reserpine-induced fibromyalgia group, and the fisetin-treated group. The carotid arteries and brains of the animals were dissected. Frozen tissue samples were used for total RNA extraction and qPCR analysis of eNOS, caspase-3, Bcl-2, LC-3, BECN-1, CHOP, and TNF-α expression. Histological, immunohistochemical (eNOS), and ultrastructure studies were conducted. The carotid arteries revealed excessive autophagy and endothelial, vascular, and apoptotic changes. The cerebral cortex showed similar findings apart from endoplasmic reticulum stress. Additionally, there was decreased gene expression of eNOS and Bcl-2 and increased expression of caspase-3, LC-3, BECN-1, CHOP, and TNF-α. In the fisetin-treated rats, improvements in the histological and molecular results were detected. In conclusion, oxidative stress, enhanced apoptosis, and excessive autophagy are fundamental pathophysiologic mechanisms of reserpine-induced fibromyalgia. Moreover, fisetin has an ameliorative effect against fibromyalgia.

The Roles of Coenzyme Q in Disease: Direct and Indirect Involvement in Cellular Functions

Coenzyme Q (CoQ) is a key component of the respiratory chain of all eukaryotic cells. Its function is closely related to mitochondrial respiration, where it acts as an electron transporter. However, the cellular functions of coenzyme Q are multiple: it is present in all cell membranes, limiting the toxic effect of free radicals, it is a component of LDL, it is involved in the aging process, and its deficiency is linked to several diseases. Recently, it has been proposed that coenzyme Q contributes to suppressing ferroptosis, a type of iron-dependent programmed cell death characterized by lipid peroxidation. In this review, we report the latest hypotheses and theories analyzing the multiple functions of coenzyme Q. The complete knowledge of the various cellular CoQ functions is essential to provide a rational basis for its possible therapeutic use, not only in diseases characterized by primary CoQ deficiency, but also in large number of diseases in which its secondary deficiency has been found.

Assessment of Platelet Mitochondrial Respiration in a Pediatric Population: A Pilot Study in Healthy Children and Children with Acute Lymphoblastic Leukemia

Characterization of mitochondrial respiration in peripheral blood cells has recently emerged as a potential biomarker for the assessment of the severity of hematological malignancies (HM) in adults. Whether changes in platelet respiratory function occur in children with or without HM it is unknown. The present pilot study was double-aimed: (i) to investigate whether platelet respiration is age-dependent in non-HM children and (ii) to assess the platelet mitochondrial respiration in children with newly diagnosed acute lymphoblastic leukemia (ALL). Blood samples obtained from age-grouped children (10–11, 13–14 and 16–17 years) with non-HM and children with ALL (10–11 years) were used to isolate platelets via differential centrifugation. High-resolution respirometry studies of isolated platelets were performed according to a protocol adapted to evaluate complex I and II-supported respiration. An age-related decrease in respiration was observed in the non-HM pediatric population and had comparable values for the 13–14 and 16–17 years. groups. In children with ALL, a significant increase in C I-supported active respiration and decrease in maximal noncoupled respiration were found at the disease onset. In conclusion, in a pediatric population, platelet mitochondrial respiration is age-dependent. Platelet respiratory dysfunction occurs in children with newly-diagnosed ALL, an observation that warrants further investigation of this change as a disease biomarker.

Interplay between genetics and lifestyle on pain susceptibility in women with fibromyalgia: The al-Ándalus project

Objectives

It is widely acknowledged that the experience of pain is promoted by both genetic susceptibility and environmental factors such as engaging in physical activity (PA), and that pain-related cognitions are also important. Thus, the purpose of the present study was to test the association of 64 polymorphisms (34 candidate genes) and the gene–gene, gene–PA and gene–sedentary behaviour interactions with pain and pain-related cognitions in women with FM.

Methods

Saliva samples from 274 women with FM [mean (s.d.) age 51.7 (7.7) years] were collected for extracting DNA. We measured PA and sedentary behaviour by accelerometers for a week, pain with algometry and questionnaires, and pain-related cognitions with questionnaires. To assess the robustness of the results, a meta-analysis was also performed.

Results

The rs6311 and rs6313 polymorphisms (5-hydroxytryptamine receptor 2A, HTR2A) were individually related to algometer scores. The interaction of rs4818 (catechol-O-methyltransferase, COMT) and rs1799971 (opioid receptor μ gene, OPRM1) was related to pain catastrophizing. Five gene–behaviour interactions were significant: the interactions of sedentary behaviour with rs1383914 (adrenoceptor alpha 1A, ADRA1A), rs6860 (charged multivesicular body protein 1A, CHMP1A), rs4680 (COMT), rs165599 (COMT) and rs12994338 (SCN9A) on bodily pain subscale of the Short Form 36. Furthermore, the meta-analysis showed an association between rs4680 (COMT) and severity of FM symptoms (codominant model, P-value 0.032).

Conclusion

The HTR2A gene (individually), COMT and OPRM1 gene–gene interaction, and the interactions of sedentary behaviour with ADRA1A, CHMP1A, COMT and SCN9A genes were associated with pain-related outcomes. Collectively, findings from the present study indicate a modest contribution of genetics and gene–sedentary behaviour interaction to pain and pain catastrophizing in women with FM. Future research should examine whether reducing sedentary behaviour is particularly beneficial for reducing pain in women with genetic susceptibility to pain.

Animal models of fibromyalgia: What is the best choice?

Fibromyalgia (FM) is a complex syndrome, with an indefinite aetiology and intricate pathophysiology that affects 2 - 3% of the world population. From the beginning of the 2000s, experimental animal models have been developed to mimic clinical FM and help obtain a better understanding of the relevant neurobiology. These animal models have enabled a broad study of FM symptoms and mechanisms, as well as new treatment strategies. Current experimental FM models include the reserpine-induced systemic depletion of biogenic amines, muscle application of acid saline, and stress-based (cold, sound, or swim) approaches, among other emerging models. FM models should: (i) mimic the cardinal symptoms and complaints reported by FM patients (e.g., spontaneous nociception, muscle pain, hypersensitivity); (ii) mimic primary comorbidities that can aggravate quality of life and lead to worse outcomes (e.g., fatigue, sleep disturbance, depression, anxiety); (iii) mimic the prevalent pathological mechanisms (e.g., peripheral and central sensitization, inflammation/neuroinflammation, change in the levels of the excitatory and inhibitory neurotransmitters); and (iv) demonstrate a pharmacological profile similar to the clinical treatment of FM. However, it is difficult for any one of these models to include the entire spectrum of clinical FM features once even FM patients are highly heterogeneous. In the past six years (2015 - 2020), a wide range of experimental FM studies has amounted to the literature reinforcing the need for an updated review. Here we have described, in detail, several approaches used to experimentally study FM, with a focus on recent studies in the field and in previously less discussed mechanisms. We highlight each model's challenges, limitations, and future directions, intending to help preclinical researchers establish the correct experimental FM model to use depending on their goals.

A genetic polymorphism that is associated with mitochondrial energy metabolism increases risk of fibromyalgia

Alterations in cellular energy metabolism have been implicated in chronic pain, suggesting a role for mitochondrial DNA. Previous studies reported associations of a limited number of mitochondrial DNA polymorphisms with specific pain conditions. In this study, we examined the full mitochondrial genomes of people with a variety of chronic pain conditions. A discovery cohort consisting of 609 participants either with or without a complex persistent pain conditions (CPPCs) was examined. Mitochondrial DNA was subjected to deep sequencing for identification of rare mutations, common variants, haplogroups, and heteroplasmy associated with 5 CPPCs: episodic migraine, irritable bowel syndrome, fibromyalgia, vulvar vestibulitis, or temporomandibular disorders. The strongest association found was the presence of the C allele at the single nucleotide polymorphism m.2352T>C (rs28358579) that significantly increased the risk for fibromyalgia (odds ratio [OR] = 4.6, P = 4.3 × 10). This relationship was even stronger in women (OR = 5.1, P = 2.8 × 10), and m.2352T>C was associated with all other CPPCs in a consistent risk-increasing fashion. This finding was replicated in another cohort (OR = 4.3, P = 2.6 × 10) of the Orofacial Pain: Prospective Evaluation and Risk Assessment study consisting of 1754 female participants. To gain insight into the cellular consequences of the associated genetic variability, we conducted an assay testing metabolic reprogramming in human cell lines with defined genotypes. The minor allele C was associated with decreased mitochondrial membrane potential under conditions where oxidative phosphorylation is required, indicating a role of oxidative phosphorylation in pathophysiology of chronic pain. Our results suggest that cellular energy metabolism, modulated by m.2352T>C, contributes to fibromyalgia and possibly other chronic pain conditions.

Comparative proteomic and transcriptomic analysis reveals high pH-induced expression signatures of Chinese shrimp Fenneropenaeus chinensis

pH has a great impact on the distribution, growth, behavior, and physiology in many aquatic animals. The comparison of proteomics between normal and high pH stress samples was successfully achieved using iTRAQ proteomic analysis to screen key response proteins and pathways. After high pH stress, 124 upregulated and 41 downregulated proteins were identified. The higher expression levels of proteins like citrate synthase, glutathione S-transferase, glutathione peroxidase, and cytochrome c oxidase are associated with oxidative stress and mitochondrial dysfunction. The upregulation of glucose-regulated protein 78 indicated that the endoplasmic reticulum stress is induced by high pH stress. There were significant upregulation expressions of V-type H⁺-ATPase, Na⁺, K⁺-ATPase, 14-3-3 protein, as well as ATP-binding cassette transmembrane transporters after high pH exposure, which indicating their important roles in response to high pH stress. The abundance of proteins involved in protein glycosylation, oxidative pentose phosphate pathway, protein export, and glutathione metabolism were found enriched in high pH group than in control group. Quantitative proteomic profiling and integrated analysis with transcriptomic data provide new insights into the mechanisms underlying the molecular response to high pH stress in Fenneropenaeus chinensis.

A theoretical framework to improve the construct for chronic pain disorders using fibromyalgia as an example

Fibromyalgia (FM) is a frequent, complex condition of chronic musculoskeletal pain with no evidence for biological correlates. For this reason, despite many efforts from the medical community, its construct still appears ill defined. Promising candidate biomarkers are critically reviewed. A research agenda is proposed for developing a clearer construct of FM. The ideal theoretical framework is one of overcoming the illness–disease dichotomy and considering reciprocal interactions between biology and behaviour. This approach may foster research in other fields of pain medicine and of medicine in general.

Targeted Treatment of Age-Related Fibromyalgia with Supplemental Coenzyme Q10

Fibromyalgia is a common chronic pain condition of unknown aetiology, although mitochondrial dysfunction, oxidative stress, and inflammation have been implicated in the pathophysiology of this disorder. Treatment generally involves physiotherapy, anticonvulsants, and antidepressant therapy; however, the symptomatic relief conferred by these treatments can be very variable, and there is a need for additional therapeutic strategies. One such treatment which is gaining a lot of interest is the use of coenzyme Q10 (CoQ10) supplementation. The therapeutic efficacy associated with CoQ10 supplementation is thought to arise from the ability of supplementation to restore an underlying deficit in CoQ10 status which has been associated with fibromyalgia together with the ability of CoQ10 to improve mitochondrial activity, restore cellular antioxidant capacity, and ameliorate inflammation. This chapter outlines the evidence supporting the therapeutic utility of CoQ10 in the treatment of fibromyalgia.

The Interplay between Oxidative Stress, Exercise, and Pain in Health and Disease: Potential Role of Autonomic Regulation and Epigenetic Mechanisms

Oxidative stress can be induced by various stimuli and altered in certain conditions, including exercise and pain. Although many studies have investigated oxidative stress in relation to either exercise or pain, the literature presents conflicting results. Therefore, this review critically discusses existing literature about this topic, aiming to provide a clear overview of known interactions between oxidative stress, exercise, and pain in healthy people as well as in people with chronic pain, and to highlight possible confounding factors to keep in mind when reflecting on these interactions. In addition, autonomic regulation and epigenetic mechanisms are proposed as potential mechanisms of action underlying the interplay between oxidative stress, exercise, and pain. This review highlights that the relation between oxidative stress, exercise, and pain is poorly understood and not straightforward, as it is dependent on the characteristics of exercise, but also on which population is investigated. To be able to compare studies on this topic, strict guidelines should be developed to limit the effect of several confounding factors. This way, the true interplay between oxidative stress, exercise, and pain, and the underlying mechanisms of action can be revealed and validated via independent studies.

Coenzyme Q10: Novel Formulations and Medical Trends

The aim of this review is to shed light over the most recent advances in Coenzyme Q10 (CoQ10) applications as well as to provide detailed information about the functions of this versatile molecule, which have proven to be of great interest in the medical field. Traditionally, CoQ10 clinical use was based on its antioxidant properties; however, a wide range of highly interesting alternative functions have recently been discovered. In this line, CoQ10 has shown pain-alleviating properties in fibromyalgia patients, a membrane-stabilizing function, immune system enhancing ability, or a fundamental role for insulin sensitivity, apart from potentially beneficial properties for familial hypercholesterolemia patients. In brief, it shows a remarkable amount of functions in addition to those yet to be discovered. Despite its multiple therapeutic applications, CoQ10 is not commonly prescribed as a drug because of its low oral bioavailability, which compromises its efficacy. Hence, several formulations have been developed to face such inconvenience. These were initially designed as lipid nanoparticles for CoQ10 encapsulation and distribution through biological membranes and eventually evolved towards chemical modifications of the molecule to decrease its hydrophobicity. Some of the most promising formulations will also be discussed in this review.

Activation of acid-sensing ion channel 3 by lysophosphatidylcholine 16:0 mediates psychological stress-induced fibromyalgia-like pain

OBJECTIVES

Fibromyalgia is commonly considered a stress-related chronic pain disorder, and daily stressors are known triggers. However, the relation between stress and pain development remains poorly defined by clinical approaches. Also, the aetiology remains largely unknown.

METHODS

We used a newly developed mouse model and lipidomic approaches to probe the causation and explore the biological plausibility for how perceived stress translates into chronic non-inflammatory pain. Clinical and lipidomic investigations of fibromyalgia were conducted for human validation.

RESULTS

Using non-painful sound stimuli as psychological stressors, we demonstrated that mice developed long-lasting non-inflammatory hyperalgesia after repeated and intermittent sound stress exposure. Elevated serum malondialdehyde level in stressed mice indicated excessive oxidative stress and lipid oxidative damage. Lipidomics revealed upregulation of lysophosphatidylcholine 16:0 (LPC16:0), a product of lipid oxidisation, in stressed mice. Intramuscular LPC16:0 injection triggered nociceptive responses and a hyperalgesic priming-like effect that caused long-lasting hypersensitivity. Pharmacological or genetic inhibition of acid-sensing ion channel 3 impeded the development of LPC16:0-induced chronic hyperalgesia. Darapladib and antioxidants could effectively alleviate the stress-induced hyperalgesia by inhibiting LPC16:0 synthesis. Clinical investigations showed that excessive oxidative stress and LPC16:0 expression also exist in patients with fibromyalgia. Moreover, LPC16:0 expression was correlated with pain symptoms in patients with high oxidative stress and disease severity.

CONCLUSIONS

Our study provides experimental evidence for the causal effect of psychological stressors on chronic pain development. The findings identify a possible pathophysiological mechanism of stress-induced chronic non-inflammatory pain at molecular, behavioural and clinical levels that might indicate a new therapeutic approach for fibromyalgia.

Dietary Interventions in the Management of Fibromyalgia: A Systematic Review and Best-Evidence Synthesis

Fibromyalgia syndrome (FMS) is characterised by chronic widespread pain alongside fatigue, poor sleep quality and numerous comorbidities. It is estimated to have a worldwide prevalence of 1.78%, with a predominance in females. Treatment interventions for fibromyalgia have limited success, leading to many patients seeking alternative forms of treatment, including modifications to their diet and lifestyle. The effectiveness of dietary changes in fibromyalgia has not been widely researched or evaluated. This systematic review identified twenty-two studies, including 18 randomised control trials (RCTs) and four cohort studies which were eligible for inclusion. In total these studies investigated 17 different nutritional interventions. Significant improvements in reported pain were observed for those following a vegan diet, as well as with the low fermentable oligo di-mono-saccharides and polyols (FODMAP) diets. Supplementation with Chlorella green algae, coenzyme Q10, acetyl-l-carnitine or a combination of vitamin C and E significantly improved measures of pain. Interpretation of these studies was limited due to the frequent poor quality of the study design, the wide heterogeneity between studies, the small sample size and a high degree of bias. Therefore, there is insufficient evidence to recommend any one particular nutritional intervention for the management of fibromyalgia and further research is needed.

Hydroxytyrosol as a Promising Ally in the Treatment of Fibromyalgia

Fibromyalgia (FM) is a chronic and highly disabling syndrome, which is still underdiagnosed, with controversial treatment. Although its aetiology is unknown, a number of studies have pointed to the involvement of altered mitochondrial metabolism, increased oxidative stress and inflammation. The intake of extra virgin olive oil, and particularly of one of its phenolic compounds, hydroxytyrosol (HT), has proven to be protective in terms of redox homeostatic balance and the reduction of inflammation. In this context, using a proteomic approach with nanoscale liquid chromatography coupled to tandem mass spectrometry, the present study analysed: (i) Changes in the proteome of dermal fibroblasts from a patient with FM versus a healthy control, and (ii) the effect of the treatment with a nutritional relevant dose of HT. Our results unveiled that fibroblast from FM show a differential expression in proteins involved in the turnover of extracellular matrix and oxidative metabolism that could explain the inflammatory status of these patients. Moreover, a number of these proteins results normalized by the treatment with HT. In conclusion, our results support that an HT-enriched diet could be highly beneficial in the management of FM.

<p>Mitochondrial Imbalance as a New Approach to the Study of Fibromyalgia</p>

Background

Fibromyalgia (FM) is a common chronic pain disease, whose pathogenic mechanism still remains elusive. Oxidative stress markers and impaired bioenergetics homeostasis have been proposed as relevant events in the pathogenesis of the disease. Hence, the aim of the study is to analyse the potential biomarkers of mitochondrial imbalance in FM patients along with coenzyme Q10 (CoQ10) as a possible treatment.

Methods

The symptomatology of patients was recorded with an adaption of the Fibromyalgia Impact Questionnaire (FIQ). Mitochondrial imbalance was tested from blood extraction and serum isolation in 33 patients diagnosed with FM and 30 healthy controls. Western blot and HPLC techniques were performed to study the different parameters. Finally, bioinformatic analysis of machine learning was performed to predict possible associations of results.

Results

CoQ10 parameter did not show evidence to be a good marker of the disease, as the values are not significantly different between control and patient groups (Student’s t-test, CI 95%). For this reason, the focus of the study changed into the ratio between mitochondrial mass and autophagy levels. The bioinformatics analysis showed a possible association between this ratio and patients’ symptomatology. Finally, the effects of coenzyme Q10 as a potential treatment for the disease were different within patients, and its efficacy may be related to the initial mitochondrial status. However, there is no statistical significance due to limitations within the sample size.

Conclusion

Our study supports the hypothesis that an imbalance in mitochondrial homeostasis is involved in the FM pathogenesis. However, whether the increase in oxidative stress is the result of mitochondrial imbalance or the cause of this disease remains an open question. The measurement of this imbalance might be used as a preliminary biomarker for the diagnosis and follow-up of patients with FM, and even for the evaluation of the effects of the different antioxidants therapies.

Relevance of Mitochondrial Dysfunction in the Reserpine-Induced Experimental Fibromyalgia Model

Fibromyalgia (FM) is one of the most common musculoskeletal pain conditions. Although the aetiology of FM is still unknown, mitochondrial dysfunction and the overproduction of reactive oxygen intermediates (ROI) are common characteristics in its pathogenesis. The reserpine experimental model can induce FM-related symptoms in rodents by depleting biogenic amines. However, it is unclear whether reserpine causes other pathophysiologic characteristics of FM. So far, no one has investigated the relevance of mitochondrial dysfunction in the reserpine-induced experimental FM model using protection- and insult-based mitochondrial modulators. Reserpine (1 mg/kg) was subcutaneously injected once daily for three consecutive days in male Swiss mice. We carried out analyses of reserpine-induced FM-related symptoms, and their modulation by using mitochondrial insult on ATP synthesis (oligomycin; 1 mg/kg, intraperitoneally) or mitochondrial protection (coenzyme Q10; 150 mg/kg/5 days, orally). We also evaluated the effect of reserpine on mitochondrial function using high-resolution respirometry and oxidative status. Reserpine caused nociception, loss in muscle strength, and anxiety- and depressive-like behaviours in mice that were consistent with clinical symptoms of FM, without inducing body weight and temperature alterations or motor impairment. Reserpine-induced FM-related symptoms were increased by oligomycin and reduced by coenzyme Q10 treatment. Reserpine caused mitochondrial dysfunction by negatively modulating the electron transport system and mitochondrial respiration (ATP synthesis) mainly in oxidative muscles and the spinal cord. These results support the role of mitochondria in mediating oxidative stress and FM symptoms in this model. In this way, reserpine-inducing mitochondrial dysfunction and increased production of ROI contribute to the development and maintenance of nociceptive, fatigue, and depressive-like behaviours.

Coenzyme Q10 supplementation alleviates pain in pregabalin-treated fibromyalgia patients via reducing brain activity and mitochondrial dysfunction

Although coenzyme Q10 (CoQ10) supplementation has shown to reduce pain levels in chronic pain, the effects of CoQ10 supplementation on pain, anxiety, brain activity, mitochondrial oxidative stress, antioxidants, and inflammation in pregabalin-treated fibromyalgia (FM) patients have not clearly elucidated. We hypothesised that CoQ10 supplementation reduced pain better than pregabalin alone via reducing brain activity, mitochondrial oxidative stress, inflammation, and increasing antioxidant levels in pregabalin-treated FM patients. A double-blind randomised placebo-controlled trial was conducted. Eleven FM patients were enrolled with 2 weeks wash-out then randomly allocated to 2 treatment groups; pregabalin with CoQ10 or pregabalin with placebo for 40 d. Then, patients in CoQ10 group were switched to placebo, and patients in placebo group were switched to CoQ10 for another 40 d. Pain pressure threshold (PPT), FM questionnaire, anxiety, and pain score were examined. Peripheral blood mononuclear cells (PBMCs) were isolated to investigate mitochondrial oxidative stress and inflammation at day 0, 40, and 80. The level of antioxidants and brain positron emission tomography (PET) scan were also determined at these time points. Pregabalin alone reduced pain and anxiety via decreasing brain activity compared with their baseline. However, it did not affect mitochondrial oxidative stress and inflammation. Supplementation with CoQ10 effectively reduced greater pain, anxiety and brain activity, mitochondrial oxidative stress, and inflammation. CoQ10 also increased a reduced glutathione levels and superoxide dismutase (SOD) levels in FM patients. These findings provide new evidence that CoQ10 supplementation provides further benefit for relieving pain sensation in pregabalin-treated FM patients, possibly via improving mitochondrial function, reducing inflammation, and decreasing brain activity.

A descriptive pilot study of mitochondrial mutations & clinical phenotype in fibromyalgia syndrome

Background & objectives:

Fibromyalgia syndrome (FMS) is one of the most common chronic pain conditions of unknown aetiology. Mitochondrial dysfunction has been reported in FMS with some studies reporting the presence of mitochondrial mutation namely A3243G, which also causes mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes. This pilot study was conducted to assess this mutation and also detect large deletions in mitochondrial DNA (mtDNA) in patients with FMS.

Methods:

Thirty female patients with FMS participated and 30 matched controls were included. Genomic DNA was subjected to polymerase chain reaction (PCR) amplification using specific primers followed by restriction digestion with ApaI enzyme to detect the specific A3243G mtDNA mutation. Long-range PCR was done in two sets to detect the large deletions in the mtDNA. Biochemical parameters including thyroid-stimulating hormone and vitamin D levels were also looked at.

Results:

None of the patients were found to carry the common mutation or large deletions. Low vitamin D level was a common finding. Hypothyroidism was found in a few patients.

Interpretation & conclusions:

Although the common mutation or large mtDNA deletions were not detected in blood mtDNA in the FMS patients, mutations in the muscle and sequence variation in mtDNA remained a possibility. Future studies in both blood and muscle tissue including mtDNA sequencing are warranted in such patients to determine if a subset of FMS patients have mitochondrial myopathy.

Assessment of platelet respiration as emerging biomarker of disease

Mitochondrial dysfunction is currently acknowledged as a central pathomechanism of most common diseases of the 21(st) century. Recently, the assessment of the bioenergetic profile of human peripheral blood cells has emerged as a novel research field with potential applications in the development of disease biomarkers. In particular, platelets have been successfully used for the ex vivo analysis of mitochondrial respiratory function in several acute and chronic pathologies. An increasing number of studies support the idea that evaluation of the bioenergetic function in circulating platelets may represent the peripheral signature of mitochondrial dysfunction in metabolically active tissues (brain, heart, liver, skeletal muscle). Accordingly, impairment of mitochondrial respiration in peripheral platelets might have potential clinical applicability as a diagnostic and prognostic tool as well as a biomarker in treatment monitoring. The aim of this minireview is to summarize current information in the field of platelet mitochondrial dysfunction in both acute and chronic diseases.

Dietary interventions in fibromyalgia: a systematic review

Fibromyalgia (FM) is a chronic non-degenerative disease, whose nutritional therapy seems controversial. This systematic review aimed to synthesize the knowledge about the effect of dietary interventions on patient-reported outcomes (PRO) and inflammation in patients with FM. Six electronic databases - PubMed, BioMed Central, Cochrane library, EMBASE, LILACS and ISI - were searched for clinical trials, in which a dietary intervention in patients with FM diagnosed was conducted. Quality of evidence assessment was measured in accordance with GRADE methodology. Seven clinical trials - 3 randomized controlled trials, 1 unrandomized clinical trial and 3 uncontrolled clinical trials were identified. Dietary approaches included gluten-free diet (n = 1), raw vegetarian diet (n = 2), low Fermentable oligo-, di- and monossacharides, alcohols and polyols (FODMAPs) diet (n = 1), hypocaloric diet (n = 2) and monosodium glutamate- and aspartame-free diet interventions (n = 1). The major PRO were pain and functional repercussion, with 5 out of 7 studies reporting an improvement. The progress in secondary outcomes was reported for fatigue (2/5 studies), sleep quality (2/3 studies), depression and anxiety (3/6 studies), quality of life (4/5 studies), gastrointestinal symptoms (1/2 studies) and inflammatory biomarkers (1/1 study). However, according to Cochrane Risk of Bias, these studies had poor statistical quality. Well-designed studies should be performed to investigate the dietary interventions effect on FM. Key messages Fibromyalgia (FM) is a chronic non-degenerative disease, whose nutritional therapy seems controversial but promising. Pain and functional repercussion in FM patients seem to improve with a hypocaloric diet, a raw vegetarian diet or a low FODMAPs diet, as much as quality of life, quality of sleep, anxiety and depression and inflammatory biomarkers. Existing studies in this subject are scarce and low quality, which does not allow conclusions to be drawn.

Chronic heart failure is characterized by altered mitochondrial function and structure in circulating leucocytes

Oxidative stress is currently viewed as a key factor in the genesis and progression of Heart Failure (HF). The aim of this study was to characterize the mitochondrial changes linked to oxidative stress generation in circulating peripheral blood mononuclear cells isolated from chronic HF patients (HF_PBMCs) in order to highlight the involvement of mitochondrial dysfunction in the pathophysiology of HF.

To assess the production of reactive oxygen species (ROS), mitochondrial function and ultrastructure and the mitophagic flux in circulating PBMCs we enrolled 15 patients with HF and a control group of ten healthy subjects. The HF_PBMCs showed a mitochondrial population consisting of damaged and less functional organelles responsible of higher superoxide anion production both at baseline and under in vitro stress conditions, with evidence of cellular apoptosis. Although the mitophagic flux at baseline was enhanced in HF_PBMCs at level similar to those that could be achieved in control PBMCs only under inflammatory stress conditions, the activation of mitophagy was unable to preserve a proper mitochondrial dynamics upon stress stimuli in HF.

In summary, circulating HF_PBMCs show structural and functional derangements of mitochondria with overproduction of reactive oxidant species. This mitochondrial failure sustains a leucocyte dysfunctional status in the blood that may contribute to development and persistence of stress conditions within the cardiovascular system in HF.

Intracellular cholesterol accumulation and coenzyme Q10 deficiency in Familial Hypercholesterolemia

Familial Hypercholesterolemia (FH) is an autosomal co-dominant genetic disorder characterized by elevated low-density lipoprotein (LDL) cholesterol levels and increased risk for premature cardiovascular disease. Here, we examined FH pathophysiology in skin fibroblasts derived from FH patients harboring heterozygous mutations in the LDL-receptor. Fibroblasts from FH patients showed a reduced LDL-uptake associated with increased intracellular cholesterol levels and coenzyme Q₁₀ (CoQ₁₀) deficiency, suggesting dysregulation of the mevalonate pathway. Secondary CoQ₁₀ deficiency was associated with mitochondrial depolarization and mitophagy activation in FH fibroblasts. Persistent mitophagy altered autophagy flux and induced inflammasome activation accompanied by increased production of cytokines by mutant cells. All the pathological alterations in FH fibroblasts were also reproduced in a human endothelial cell line by LDL-receptor gene silencing. Both increased intracellular cholesterol and mitochondrial dysfunction in FH fibroblasts were partially restored by CoQ₁₀ supplementation. Dysregulated mevalonate pathway in FH, including increased expression of cholesterogenic enzymes and decreased expression of CoQ₁₀ biosynthetic enzymes, was also corrected by CoQ₁₀ treatment. Reduced CoQ₁₀ content and mitochondrial dysfunction may play an important role in the pathophysiology of early atherosclerosis in FH. The diagnosis of CoQ₁₀ deficiency and mitochondrial impairment in FH patients may also be important to establish early treatment with CoQ₁₀.

The inflammasome as a target for pain therapy

The interleukin-1 family of cytokines are potent inducers of inflammation and pain. Proteolytic activation of this family of cytokines is under the control of several innate immune receptors that coordinate to form large multiprotein signalling platforms, termed inflammasomes. Recent evidence suggests that a wide range of inflammatory diseases, cancers, and metabolic and autoimmune disorders, in which pain is a common complaint, may be coordinated by inflammasomes. Activation of inflammasomes results in cleavage of caspase-1, which subsequently induces downstream initiation of several potent pro-inflammatory cascades. Therefore, it has been proposed that targeting inflammasome activity may be a novel and effective therapeutic strategy for these pain-related diseases. The purpose of this narrative review article is to provide the reader with an overview of the activation and regulation of inflammasomes and to investigate the potential therapeutic role of inflammasome inhibition in the treatment of diseases characterized by pain, including the following: complex regional pain syndrome, gout, rheumatoid arthritis, inflammatory pain, neuropathic pain, chronic prostatitis, chronic pelvic pain syndrome, and fibromyalgia. We conclude that the role of the inflammasome in pain-associated diseases is likely to be inflammasome subtype and disease specific. The currently available evidence suggests that disease-specific targeting of the assembly and activity of the inflammasome complex may be a novel therapeutic opportunity for the treatment of refractory pain in many settings.

Effect of coenzyme Q10 on mitochondrial respiratory proteins in trigeminal neuralgia

Trigeminal neuralgia (TN) is the neuropathic pain. Mitochondrial dysfunction, increased oxidative stress, and inflammation demonstrated in chronic pain. Carbamazepine (CBZ) is the first-line drug for TN, however, it is still insufficient. Coenzyme Q10 (CoQ10) has been used as the additional supplement for pain therapy. Nonetheless, mitochondrial respiratory proteins, oxidative stress, and inflammation in TN, and the add-on effects of CoQ10 on those defects have never been investigated. CBZ-treated TN-patients, naïve TN-patients, and control subjects were included. CBZ-treated TN-patients were randomised into two subgroups, received either CoQ10 or placebo for 2 months. Pain levels were evaluated, and peripheral blood mononuclear cells were isolated to determine the oxidative stress, mitochondrial oxidative phosphorylation (OXPHOS), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), and cytokines including TNF-α, IL-1β and IL-18 mRNA expression. Pain scales, oxidative stress, and OXPHOS levels were greater in naïve TN-patients than control, whereas the cytokine profiles were unchanged. Although pain scales were lower in CBZ-treated TN-patients than in naïve TN-patients, oxidative stress, OXPHOS, and cytokine expression profiles were not different. PGC-1α levels found to be increased in CBZ-treated TN patients when compared with the naïve group. CoQ10 supplement in CBZ-treated TN patients reduced pain scale and oxidative stress and increased antioxidants levels when compared with placebo group. However, OXPHOS, PGC-1α, and cytokines were not different between groups. These findings suggest that increased oxidative stress could be potentially involved in the pathogenesis of TN. CoQ10 supplements can reduce oxidative stress, leading to more effective pain reduction in TN patients being treated with CBZ.

A narrative review on the difficulties associated with fibromyalgia diagnosis

Fibromyalgia presents a clinical enigma as its pathophysiology is not well understood and its symptoms are nonspecific and overlap with many disorders, making its diagnosis a challenge for clinicians and researchers. Efforts have been made to develop a set of diagnostic criteria for this disorder. However, these criteria rely heavily on expert clinician opinion and produce a large heterogeneity within the diagnosed population. With no present specific technique reflecting the underlying pathophysiology of fibromyalgia, a definitive diagnosis of fibromyalgia remains elusive. This review discusses some problems and challenges associated with fibromyalgia diagnosis and presents some novel findings on the pathophysiological nature of fibromyalgia.

Blood-Based Bioenergetic Profiling Reflects Differences in Brain Bioenergetics and Metabolism

Blood-based bioenergetic profiling provides a minimally invasive assessment of mitochondrial health shown to be related to key features of aging. Previous studies show that blood cells recapitulate mitochondrial alterations in the central nervous system under pathological conditions, including the development of Alzheimer's disease. In this study of nonhuman primates, we focus on mitochondrial function and bioenergetic capacity assessed by the respirometric profiling of monocytes, platelets, and frontal cortex mitochondria. Our data indicate that differences in the maximal respiratory capacity of brain mitochondria are reflected by CD14+ monocyte maximal respiratory capacity and platelet and monocyte bioenergetic health index. A subset of nonhuman primates also underwent [18F] fluorodeoxyglucose positron emission tomography (FDG-PET) imaging to assess brain glucose metabolism. Our results indicate that platelet respiratory capacity positively correlates to measures of glucose metabolism in multiple brain regions. Altogether, the results of this study provide early evidence that blood-based bioenergetic profiling is related to brain mitochondrial metabolism. While these measures cannot substitute for direct measures of brain metabolism, provided by measures such as FDG-PET, they may have utility as a metabolic biomarker and screening tool to identify individuals exhibiting systemic bioenergetic decline who may therefore be at risk for the development of neurodegenerative diseases.