Conceived and designed the experiments: MDC JASA. Performed the experiments: MDC EAG. Analyzed the data: MDC FJCG EAG FJCG MDM. Contributed reagents/materials/analysis tools: MDC MDM JASA. Wrote the paper: MDC JASA.
The authors have declared that no competing interests exist.
Fibromyalgia (FM) is a chronic pain syndrome with unknown etiology and a wide spectrum of symptoms such as allodynia, debilitating fatigue, joint stiffness and migraine. Recent studies have shown some evidences demonstrating that oxidative stress is associated to clinical symptoms in FM of fibromyalgia. We examined oxidative stress and bioenergetic status in blood mononuclear cells (BMCs) and its association to headache symptoms in FM patients. The effects of oral coenzyme Q10 (CoQ10) supplementation on biochemical markers and clinical improvement were also evaluated.
We studied 20 FM patients and 15 healthy controls. Clinical parameters were evaluated using the Fibromyalgia Impact Questionnaire (FIQ), visual analogues scales (VAS), and the Headache Impact Test (HIT-6). Oxidative stress was determined by measuring CoQ10, catalase and lipid peroxidation (LPO) levels in BMCs. Bioenergetic status was assessed by measuring ATP levels in BMCs.
We found decreased CoQ10, catalase and ATP levels in BMCs from FM patients as compared to normal control (P<0.05 and P<0.001, respectively) We also found increased level of LPO in BMCs from FM patients as compared to normal control (P<0.001). Significant negative correlations between CoQ10 or catalase levels in BMCs and headache parameters were observed (r = −0.59, P<0.05; r = −0.68, P<0.05, respectively). Furthermore, LPO levels showed a significant positive correlation with HIT-6 (r = 0.33, P<0.05). Oral CoQ10 supplementation restored biochemical parameters and induced a significant improvement in clinical and headache symptoms (P<0.001).
The results of this study suggest a role for mitochondrial dysfunction and oxidative stress in the headache symptoms associated with FM. CoQ10 supplementation should be examined in a larger placebo controlled trial as a possible treatment in FM.
Fibromyalgia (FM) is a common chronic pain syndrome with an unknown etiology, which has been associated with a wide spectrum of symptoms such as allodynia, debilitating fatigue, joint stiffness and depression. FM is diagnosed according to the classification criteria established by the American College of Rheumatology (ACR)
Recently, oxidative stress has been proposed as a relevant event in the pathogenesis of FM and headaches
CoQ10 levels and mitochondrial dysfunction have also been implicated in the pathophysiology of migraine, and it has been reported that oral CoQ10 supplementation improved clinical symptoms
The aim of this paper was first to establish a possible correlation between oxidative stress parameters and severity of headaches in FM, and secondly to study the effects of oral CoQ10 supplementation on the improvement in headache symptoms.
Written informed consent and the approval of the ethical committee of University Pablo de Olavide and Universitary Hospital Virgen Macarena from Seville were obtained, according to the principles of the Declaration of Helsinki.
All samples were obtained after informed consent from patients and the approval of the local ethical committee was obtained according to the principles of the Declaration of Helsinki. The study consisted of 20 women diagnosed with FM and 15 healthy women. The inclusion criteria was fibromyalgia that had been diagnosed for the previous 2 to 3 years, based on the current ACR diagnostic criteria 1. Exclusion criteria were acute infectious diseases in the previous 3 weeks; past or present neurological, psychiatric, metabolic, autoimmune, allergy-related, dermal or chronic inflammatory disease; undesired habits (e.g., smoking, alcohol, etc.); oral diseases (e.g., periodontitis); medical conditions that required glucocorticoid treatment, use of analgesics, statin or antidepressant drugs; past or current substance abuse or dependence and pregnancy or current breastfeeding. Healthy controls had no signs or symptoms of FM and were free of any medication for at least 3 weeks before the study began. All patients and controls had taken no drugs or vitamin/nutritional supplement during the 3 week period prior to the collection of the blood samples. Before the study, the patients reported using paracetamol on demand. Clinical data was obtained from physical examination, and evaluated using the Fibromyalgia Impact Questionnaire (FIQ) including visual analogues scales about general and diffuse pain typical of FM (VAS), and Headache Impact Test (HIT-6).
Heparinized blood samples were collected after 12-hours fasting from patients and healthy age and sex-matched control subjects. BMCs were purified from heparinized blood by isopycnic centrifugation using Histopaque-1119 and Histopaque-1077 (Sigma Chemical Co., St. Louis, MO, USA).
CoQ10 content in BMCs were analyzed by HPLC (Beckman Coulter, Brea, CA, USA; 166-126 HPLC) with ultraviolet detection (275 nm), according to the method described above
Lipid peroxidation in cells was determined by analyzing the accumulation of lipoperoxides using a commercial kit from Cayman Chemical (Ann Arbor, Michigan, USA). TBARS are expressed in terms of malondialdehyde (MDA) levels. In these assays, an MDA standard is used to construct a standard curve against which unknown samples can be plotted.
A spectrophotometric method described by Beer and Sizer (1952)
ATP levels were determined by a bioluminescence assay using an ATP determination kit from Invitrogen-Molecular Probes (Eugene, OR, USA) according to the instructions of the manufacturer.
Ten volunteer patients were supplemented with CoQ10 (Pharma Nord, Vejle, Denmark) with soft gel capsules for 3 months (300 mg/day CoQ10 divided in three doses). After 3 months of treatment, heparinized blood samples were collected after 12-hours fasting and 24 hours after the last dose, and clinical symptoms were evaluated. The CoQ10 formulation consisted of soft gelatin capsules containing 100 mg of ubiquinone emulsified with diglyceryl monooleate, beeswax, soy lecithin and canola oil.
All results are expressed as mean ± SD unless stated otherwise. The unpaired Student's t test was used to evaluate the significance of differences between groups. Statistical analyses included Pearson's correlations between CoQ10, catalase, and MDA levels in compared with Hit-6 score. P values less than 0.05 were considered significant. Data were analysed using the SPSS/PC statistical software package (SPSS for Windows, 19, 2010, SPSS Inc. Chicago, IL, USA).
The mean age of patients was 46.6±5 years for the FM group and 44.9±4 years for the control group. The mean duration of symptoms in the FM group was 10.1±4.2 years. The mean tender point score in the FM group was 14.8±1.7 points. According to International Headache Society (IHS) criteria, the headache was tension-type headache. The mean of frequency of headache was 3±1 per week. The duration of headache episodes was 10±2 hours. The patients did not describe any symptoms such as nausea, photophobia, or aura.
The most prominent features of these FM patients were pain and stiffness. They were sedentary people and routine laboratory tests yielded normal results for glucose, urea, uric acid, total protein, creatinine, aspartate aminotransferase, alanine aminotransferase, cholesterol and triglycerides (data not shown). The number and subgroup distribution of BMCs (monocytes and limphocytes) in FM patients were in the normal range (data not shown).
To evaluate the antioxidant system in FM patients, CoQ10 and catalase levels in BMCs were examined and compared to control subjects. Both, CoQ10 and catalase levels were significantly reduced in FM patients, 64.3% and 40% respectively (
(A) CoQ10 levels were measured by HPLC, as described in Materials and Methods. (B) Catalase was analyzed in BMCs as described in Materials and Methods. (C) LPO was measured as described in Material and Methods. (D) ATP levels were analyzed in BMCs as described in Materials and Methods. Data represent the mean ± SD of three separate experiments.
To determine whether the observed CoQ10 deficiency had an effect on cellular bioenergetics, we measured intracellular ATP levels in BMCs from control and FM patients. ATP levels were reduced to 70% of the control value in BMCs from FM patients (
All FM patients showed high HIT-6 scores compared with control subjects (
Patients (n = 20) | Control (n = 15) | |||
Age (yr) | 46.6 | ±5 | 44.9 | ±4 |
Tender points | 14.8 | ±1.7 | --- | |
Duration of disease (years) | 10.1 | ±4.2 | --- | |
FIQ Total score, range 0–100 | 60.2 | ±5.6 |
7.1 | ±1.4 |
VAS, range 0–10 | 6.9 | ±1.3 |
0.8 | ±0.3 |
HIT-6, range 36–78 | 61.8 | ±1.3 |
36.1 | ±1.1 |
VAS: Visual Analogue Scale; FIQ: Fibromyalgia Impact Questionnaire; HIT-6: Headache Impact Test. Values are means ±SD,
P<0.001.
Pre-treatment (n = 10) | Post-treatment (n = 10) | Control levels (n = 15) | |
Tender points | 13.9±1.2 | 9±0.5 |
--- |
FIQ total score, range 0–100 | 59.2±4.2 |
30.1±2 |
7.1±1.4 |
VAS, range 0–10 | 7.1±1.2 |
3.5±0.8 |
0.8±0.3 |
HIT-6, range 36–78 | 60.8±1.4 |
36.9±1.7 |
36.1±1.1 |
CoQ10 (pmolQ/mg protein) | 135.6±6.3 |
221.6±11.3 |
224.4±12.3 |
ATP (nmol/mg protein) | 61.3±4.9 |
191.1±6.7 |
202.8±22.1 |
Catalase (U/mg protein) | 35.6±10.1 |
85.2±15.3 |
96.5±14.8 |
MDA in BMCs (nmol/million cells) | 30.3±5.9 |
5.1±1.6 |
6±1 |
VAS: Visual Analogue Scale; FIQ: Fibromyalgia Impact Questionnaire; HIT-6: Headache Impact Test; MDA: Malondialdehyde; BMCs: Blood mononuclear cells. Values are means ±SD,
P<0.001 between pre and post treatment;
P<0.001 between pretreatment and control.
We observed a significant increase of CoQ10 levels after treatment (135.6±6.3 pretreatment and 221.6±11.3 postreatment, P<0.001) (respect to control, 224.4±12.3;P<0.001), ATP levels (61.3±4.9 pretreatment and 191.1±6.7 postreatment, P<0.001) (respect to control, 202.8±22.1;P<0.001) and catalase levels (35.6±10.1 pretreatment and 85.2±15.3 postreatment, P<0.001) (respect to control, 96.5±14.8; P<0.001) in BMCs, a reduction of LPO levels (30.3±5.9 pretreatment and 5.1±1.6 postreatment, P<0.001) (respect to control, 6±1; P<0.001) and a marked improvement of clinical symptoms (FIQ: P<0.01; VAS: P<0.01; HIT-6: P<0.05) (
In the present study we have confirmed a significant increase of oxidative stress in FM patients, showing a marked decrease of CoQ10, ATP and catalase levels and a significant increase of LPO levels in BMCs compared to control subjects.
Coenzyme Q10 (CoQ10) is present in every membrane of all cells in the body. CoQ10 transfers electrons from complexes I and II to complex III in the mitochondrial respiratory chain and fulfills a critical role in mitochondrial ATP production, playing a crucial role in cellular metabolism; regulating mitochondrial uncoupling proteins, the mitochondrial permeability transition pore, β-oxidation of fatty acids, nucleotide metabolism and production of reactive oxygen species (ROS)
Our results show an important significant correlation between LPO levels and headache symptoms in FM patients. Antioxidants (CoQ10 and catalase) levels also showed a significant negative correlation with headache symptoms. CoQ10 has two important functions in cells: first, CoQ10 is a mitochondrial cofactor with the potential to boost mitochondrial function, and second, CoQ10 is a powerful free radical scavenger that can mitigate lipid peroxidation and DNA damage caused by oxidative stress
Mitochondria have long been postulated to be involved in the etiology of migraines, although a direct link has not been identified
Clinical studies have generated evidence that FM is associated with immune dysregulation of circulatory levels of pro-inflammatory cytokines, affecting neural function of pain-related neurotransmitters
In addition of pro-inflammatory cytokines, CoQ10 deficiency is also involved in inflammation. A significant negative correlation has been observed between CoQ10 and pro-inflammatory markers in septic shock patients
In summary, headache symptoms in FM could be a consequence of oxidative stress and both may share common pathophysiologic basis. Furthermore, CoQ10 treatment showed a remarkable improvement in clinical symptoms and headache in FM. Detection of CoQ10 deficiency and subsequent CoQ10 supplementation may result in clinical improvement in FM. Further analysis involving doubled-blind placebo-controlled clinical trials will be required to confirm this observation.
We thank all patients for participating in the study.