Smoking is Associated with Reduced Leptin and Neuropeptide Y Levels and Higher Pain Experience in Patients with Fibromyalgia

Smoking deregulates neuroendocrine responses to pain supporting production of neuropeptide Y (NpY) by direct stimulation of nicotinic receptors or by inhibiting adipokine leptin. Present study addressed the effect of cigarette smoking on adipokines and pain parameters, in 62 women with fibromyalgia (FM) pain syndrome with unknown etiology. Pain was characterized by a visual analogue scale, tender point (TP) counts, pressure pain threshold, and neuroendocrine markers NpY and substance P (sP). Levels of IGF-1, leptin, resistin, visfatin, and adiponectin were measured in blood and cerebrospinal fluid. Current smokers (n=18) had lower levels of leptin compared to ex-smokers (n=25, P=0.002), while the expected NpY increase was absent in FM patients. In smokers, this was transcribed in higher VAS-pain (P=0.04) and TP count (P=0.03), lower pain threshold (P=0.01), since NpY levels were directly related to the pain threshold (rho=0.414) and inversely related to TP counts (rho=-0.375). This study shows that patients with FM have no increase of NpY levels in response to smoking despite the low levels of leptin. Deregulation of the balance between leptin and neuropeptide Y may be one of the essential mechanisms of chronic pain in FM

Profile of Cerebrospinal microRNAs in Fibromyalgia

<div><p>Introduction</p><p>Fibromyalgia (FM) is characterized by chronic pain and reduced pain threshold. The pathophysiology involves disturbed neuroendocrine function, including impaired function of the growth hormone/insulin-like growth factor-1 axis. Recently, microRNAs have been shown to be important regulatory factors in a number of diseases.</p> <p>The aim of this study was to try to identify cerebrospinal microRNAs with expression specific for FM and to determine their correlation to pain and fatigue. </p> <p>Methods</p><p>The genome-wide profile of microRNAs in cerebrospinal fluid was assessed in ten women with FM and eight healthy controls using real-time quantitative PCR. Pain thresholds were examined by algometry. Levels of pain (FIQ pain) were rated on a 0-100 mm scale (fibromyalgia impact questionnaire, FIQ). Levels of fatigue (FIQ fatigue) were rated on a 0-100 mm scale using FIQ and by multidimensional fatigue inventory (MFI-20) general fatigue (MFIGF).</p> <p>Results</p><p>Expression levels of nine microRNAs were significantly lower in patients with FM patients compared to healthy controls. The microRNAs identified were miR-21-5p, miR-145-5p, miR-29a-3p, miR-99b-5p, miR-125b-5p, miR-23a-3p, 23b-3p, miR-195-5p, miR-223-3p.</p> <p>The identified microRNAs with significantly lower expression in FM were assessed with regard to pain and fatigue. miR-145-5p correlated positively with FIQ pain (r=0.709, p=0.022, n=10) and with FIQ fatigue (r=0.687, p=0.028, n=10). </p> <p>Conclusion</p><p>To our knowledge, this is the first study to show a disease-specific pattern of cerebrospinal microRNAs in FM.</p> <p>We have identified nine microRNAs in cerebrospinal fluid that differed between FM patients and healthy controls. One of the identified microRNAs, miR-145 was associated with the cardinal symptoms of FM, pain and fatigue.</p> </div

Controlled, cross-sectional, multi-center study of physical capacity and associated factors in women with fibromyalgia

Background: Health and physical capacity are commonly associated with disease, age, and socioeconomic factors. The primary objective of this study was to investigate the degree to which physical capacity, defined as muscle strength and walking ability, is decreased in women with fibromyalgia (FM), as compared to healthy women, who are matched for age and level of education. The secondary aim was to investigate whether muscle strength and walking ability are associated with age, symptom duration, activity limitations and, Body Mass Index (BMI) in women with FM and control subjects. Methods: This controlled, cross-sectional, multi-center study comprised 118 women with FM and 93 age-and education-level-matched healthy women. The outcome measures were isometric knee-extension force, isometric elbow-flexion force, isometric hand-grip force, and walking ability. Differences between the groups were calculated, and for the women with FM analyses of correlations between the measures of physical capacity and variables were performed. Results: The women with FM showed 20% (p amp;lt; 0.001) lower isometric knee-extension force, 36% (p amp;lt; 0.001) lower isometric elbow-flexion force, 34% (p amp;lt; 0.001) lower isometric hand-grip force, and 16% lower walking ability (p amp;lt; 0.001), as compared to the healthy controls. All measures of muscle strength in women with FM showed significant weak to moderate relationship to symptom duration (r(s) = -0.23-0.32) and walking ability (r(s) = 0.25-0.36). Isometric knee-extension force correlated with activity limitations, as measured using the SF-36 Physical function subscale (r(s)= 0.23, p = 0.011). Conclusions: Physical capacity was considerably decreased in the women with FM, as compared to the age-and education-level-matched control group. All measures of physical capacity showed a significant association with symptom duration. Knee-extension force and walking ability were significantly associated with activity limitations, age, and BMI. It seems important to address this problem and to target interventions to prevent decline in muscle strength. Assessments of muscle strength and walking ability are easy to administer and should be routinely carried out in the clinical setting for women with FM.Funding Agencies|Swedish Rheumatism Association; Swedish Research Council [K2009-52P-20943-03-2, K2011-69X-21874-01-6, K2009-69P-21300-04-4, K2013-52X-22199-01-3, K2015-99x-21874-05-04]; Health and Medical Care Executive Board of Vastra Gotaland Region; ALF-LUA at Sahlgrenska University Hospital; Gothenburg Center for Person Centered Care (GPCC); AFA Insurance [140341]; Stockholm County Council (ALF); Karolinska Institutet Foundation</p