The pain profile in fibromyalgia : Painomic studies of pain characteristics and proteins in blood

Chronic widespread pain (CWP), including fibromyalgia (FM), is a complex pain condition, where little is known about the molecular mechanisms contributing to its pathophysiology. To date, there are no established biomarkers for CWP/FM. This thesis has investigated potential molecular mechanisms and biomarkers in blood for chronic pain in women with CWP/FM. Furthermore, investigations are made to evaluate whether common pain characteristics such as pain intensity, sensitivity, and psychological distress in CWP/FM are correlated with specific proteins in blood. The pain profile of CWP/FM, which includes the plasma proteome and clinical characteristics, is analyzed using proteomics, advanced multivariate statistics, and bioinformatics. The results from paper I, III, and IV indicate that there are prominent systemic changes related to immunity, inflammation, and metabolic processes in women with CWP/FM compared to healthy controls. Furthermore, paper II and III show that in CWP/FM, pain intensity is related to protein profiles involved in immunity processes, psychological distress with metabolic and immunity processes, and pain sensitivity with inflammatory processes. In paper IV, the plasma proteome is investigated before and after a 15 weeks resistance exercise intervention in FM and healthy controls. Both at baseline and post exercise in FM and controls, prominent protein alterations are found that are involved in immunity, stress, mRNA stability, and muscle structure development. Exercise seems to influence clinical characteristics and circulating proteins in FM. Furthermore, specific plasma proteome profile is found related to grade of chronification, pain sensitivity, and improved muscle force of the quadriceps muscle. To summarize, the results from this thesis suggest that in CWP/FM there might be a dysregulation in the biological processes involved in the immune system and metabolic processes, which are tightly linked to several proteins in the complement system and blood coagulation cascade. These results shed light on potential ongoing mechanisms involved in the pathophysiology of the complex pain condition CWP/FM. This type of biomarker research has a large potential in increasing knowledge about mechanisms involved in CWP/FM and can hereby open for better clinical understanding and management of this and other chronic pain states. The clinical value of collecting a blood sample and measuring stable pain mechanism markers in combination with evaluation of anamnesis and clinical examination would in the future help clinicians and patients receive a faster and more precise diagnosis and ultimately better treatment strategies.Långvarig smärta har blivit vanligare bland befolkningen och är idag ett stort hälsoproblem. Ca 1 av 10 drabbas av generaliserad smärta (engelska: chronic widespread pain, CWP) dvs smärta spridd över hela kroppen. Fibromyalgi (FM), som ingår i CWP drabbar ca 1-4% av befolkningen och är vanligare bland kvinnor än män. Det är vanligt att personer med CWP/FM utöver sin spridda smärta även upplever trötthet, sömnsvårigheter, depression, ångest, ökad smärtkänslighet och stelhet av muskler och leder. Symtomen har i sin tur stor påverkan på arbetsförmåga, hälsa och livskvalitet. Idag är dem bakomliggande orsakerna för CWP/FM ofullständigt kartlagda och det finns inga markörer som på ett objektivt sätt kan fastställa diagnos. Syftet med denna avhandling är att undersöka hur proteiner i blod skiljer sig åt mellan kvinnor med CWP/FM och friska kvinnliga kontroller. Vidare har syftet varit att undersöka om kliniska variabler, till exempel smärtintensitet, smärtkänslighet och psykologisk belastning (ångest/depression), har ett samband med proteinmönster i blod. Slutligen har effekten av ett 15 veckors träningsprogram och dess påverkan på proteiner i blod samt kliniska variabler hos kvinnor med FM och friska kontroller analyserats. I studie I, III, och IV studerades proteinmönstret i blod mellan CWP/FM och kontroller. Resultatet visade att flertalet proteiner kunde urskilja CWP/FM gruppen från kontrollerna. Dessa proteiner var involverade i flertalet förlopp i kroppen bland annat inflammation, metabolism och immunförsvar. I studie II och III undersöktes om det funna proteinmönstret i blod hade något samband med smärtintensitet, smärtkänslighet och psykologisk belastning hos denna specifika CWP/FM grupp. Resultatet visade att det fanns ett specifikt proteinmönster kopplat till respektive undersökt variabel. Smärtintensitet var relaterat till proteiner involverade i immunförsvar; smärtkänslighet var relaterat till proteiner inom inflammation; och psykologisk belastning var relaterat till proteiner inom metabolism och immunförsvar. I studie IV studerades proteinmönstret i blod före och efter 15 veckors styrketräning hos FM samt friska kontroller. Resultaten visade att det fanns förändringar i specifika proteiner involverade i flertalet förlopp i kroppen bland annat stress, processer för muskelstrukturutveckling samt immunförsvar. Vidare sågs även ett specifikt mönster av proteiner som kunde relateras till smärtans varaktighet (dvs hur länge man levt med smärta), smärtkänslighet samt förbättrad muskelstyrka i lårmuskeln. Styrketräning visade sig ha en positiv effekt på flera av de rapporterade symtomen hos FM gruppen och till viss del påverkades även proteinmönstret. Sammanfattningsvis har studierna i denna avhandling visat att i denna specifika CWP/FM grupp finns skillnader i proteinmönstret i blod jämfört med friska kontroller. Det funna proteinmönstret är främst involverat i olika förlopp inom blodkoagulation samt olika komponenter kopplade till immunförsvaret. Genom identifieringen av dessa specifika proteinmönster i blodet hos CWP/FM kan det bidra till ökad förståelse av bakomliggande sjukdomsmekanismer hos denna patientgrupp. Detta kan i framtiden bidra till underlättandet av diagnosticering, behandling, rehabilitering och slutligen skapa kliniska verktyg i form av smärtmarkörer vid utredning av olika långvariga smärttillstånd

Plasma protein patterns are strongly correlated with pressure pain thresholds in women with chronic widespread pain and in healthy controls-an exploratory case-control study

Chronic widespread pain (CWP) is a complex pain condition characterized by generalized musculoskeletal pain and often associated with other symptoms. An important clinical feature is widespread increased pain sensitivity such as lowered pain thresholds for mechanical stimuli (pressure pain thresholds [PPT]). There is a growing interest in investigating the activated neurobiological mechanisms in CWP, which includes fibromyalgia. In CWP, strong significant correlations have been found between muscle protein patterns and PPT. This explorative proteomic study investigates the multivariate correlation pattern between plasma proteins and PPT in CWP and in healthy controls (CON). In addition, this study analyses whether the important proteins for PPT differ between the 2 groups. Using 2-dimensional gel electrophoresis, we analyzed the plasma proteome of the CWP (n = 15) and the CON (n = 23) and proteins were identified using mass spectrometry. For both the CWP and the CON, the associations between the identified proteins and PPT were analyzed using orthogonal partial least square in 2 steps. Significant associations between certain plasma proteins and PPT existed both in CWP (R-2 = 0.95;P = .006) and in CON (R-2 = 0.89;P &amp;lt; .001). For both groups of subjects, we found several proteins involved in PPT that reflect different biological processes. The plasma proteins as well as the biological processes involved in PPT differed markedly between the 2 groups of subjects. This study suggests that plasma protein patterns are associated with pain thresholds in CWP. Using the plasma proteome profile of CWP to study potential biomarker candidates could provide a snapshot of ongoing systemic mechanisms in CWP.Funding Agencies|Swedish Research CouncilSwedish Research Council [2018-02470]; Medical Research Council of Southeast Sweden [159031]; County Council of Ostergotland [LIO-445161, SC-2013-00395-36, LIO-700931]; Ake Wiberg foundation [M16-0134]</p

Altered Plasma Proteins in Myogenous Temporomandibular Disorders

The aims of this study were (1) to compare the levels and interactions of several plasma proteins in patients with myogenous temporomandibular disorders (TMDM) compared to healthy and pain-free controls, (2) to compare the levels and interactions in two TMDM subgroups, myalgia (MYA) and myofascial pain (MFP), and (3) to explore associations between the proteins and clinical data. Thirty-nine patients with TMDM (MFP, n = 25, MYA, n = 14), diagnosed according to the diagnostic criteria for TMD (DC/TMD), aged 38 years, and sex-matched pain-free controls completed an extended DC/TMD Axis II questionnaire and the plasma concentration of 87 biomarkers were analyzed. Nine proteins separated TMDM from controls (p = 0.0174) and 12 proteins separated MYA from MFP (p = 0.019). Pain duration, characteristic pain intensity, pain catastrophizing, perceived stress, and insomnia severity were significantly associated with protein markers (p p < 0.022). In conclusion, several plasma proteins were upregulated in TMDM and either upregulated or downregulated in MYA compared to MFP. Some proteins in TMDM were associated with pain variables, sleep disturbance, and emotional function. These results show that systemic differences in protein expression exist in patients with TMDM and that altered levels of specific plasma proteins are associated with different clinical variables

Thermal Pain Thresholds Are Significantly Associated with Plasma Proteins of the Immune System in Chronic Widespread Pain-An Exploratory Pilot Study Using Multivariate and Network Analyses

Chronic widespread pain (CWP), including fibromyalgia (FM), is characterized by generalized musculoskeletal pain. An important clinical feature is widespread increased pain sensitivity such as lowered pain thresholds for different stimuli such as heat (HPT) and cold (CPT). There is a growing interest in investigating the activated neurobiological mechanisms in CWP. This explorative proteomic study investigates the multivariate correlation pattern between plasma and muscle proteins and thermal pain thresholds in CWP and in healthy controls (CON). In addition, we analysed whether the important proteins and their networks for CPT and HPT differed between CWP and CON. We used a proteomic approach and analysed plasma and muscle proteins from women with CWP (n = 15) and CON (n = 23). The associations between the proteins and CPT/HPT were analysed using orthogonal partial least square (OPLS). The protein-protein association networks for the important proteins for the two thermal pain thresholds were analysed using STRING database. CWP had lowered pain thresholds for thermal stimulus. These levels were generally not related to the included clinical variables except in CWP for HPT. Highly interacting proteins mainly from plasma showed strong significant associations with CPT and HPT both in CWP and in CON. Marked differences in the important proteins for the two thermal pain thresholds were noted between CWP and CON; more complex patterns emerged in CWP. The important proteins were part of the immune system (acute phase proteins, complement factors, and immunoglobulin factors) or known to interact with the immune system. As expected, CWP had lowered pain thresholds for thermal stimulus. Although different proteins were important in the two groups, there were similarities. For example, proteins related to the host defence/immunity such as acute phase proteins, complement factors, immunoglobulin factors, and cytokines/chemokines (although not in CON for CPT) were important habitual/tonic factors for thermal pain thresholds. The fact that peripheral proteins contribute to thermal pain thresholds does not exclude that central factors also contribute and that complex interactions between peripheral and central factors determine the registered pain thresholds in CWP.Funding Agencies|Swedish Research CouncilSwedish Research CouncilEuropean Commission [2018-02470]</p

The Dynamic Computer Workstation-A Pilot Study of Clinical and Biochemical Investigation during Work at Static Respectively Mobile Keyboards

A large and increasing number of the work force in the population spend their work hours at the keyboard. There is evidence that repetitive high levels of static work, or extreme working postures involving the neck-shoulder muscles are an increased risk for chronic neck-shoulder pain. The aim of this study was to investigate the effect of dynamic computer working (DCW), using a mobile application to the desk surface, on pain characteristics and biomarkers in office workers. We included 10 female subjects. All subjects answered questionnaires about general health, pain intensity and characteristics. The pressure pain threshold (PPT), neck range and motion, neck and shoulder strength were measured. Microdialysis was conducted in trapezius muscle. Measurements were performed before and 4 weeks after DCW. Multivariate analysis, orthogonal partial least square discriminate analysis (OPLS-DA) and univariate analysis paired test, Wilcoxon, was performed. There was significant improvement in reported neck pain, quality of life, and psychological distress after 4 weeks DCW. The PPT and strength in neck and shoulder were significantly increased after DCW. A significant OPLS-DA model showed clear separation between the samples collected before and after 4 weeks DCW. In conclusion, these results show that keyboard work at a movable desk application might decrease the risk of repetitive strain injuries in the neck and shoulder muscles.Funding Agencies|VinnovaVinnova [2017-04091]; Region Ostergotland</p

Proteomic investigation of protein adsorption to cerebral microdialysis membranes in surgically treated intracerebral hemorrhage patients-a pilot study

Background Cerebral microdialysis (CMD) is a minimally invasive technique for sampling the interstitial fluid in human brain tissue. CMD allows monitoring the metabolic state of tissue, as well as sampling macromolecules such as proteins and peptides. Recovery of proteins or peptides can be hampered by their adsorption to the CMD membrane as has been previously shown in-vitro,however, protein adsorption to CMD membranes has not been characterized following implantation in human brain tissue. Methods In this paper, we describe the pattern of proteins adsorbed to CMD membranes compared to that of the microdialysate and of cerebrospinal fluid (CSF). We retrieved CMD membranes from three surgically treated intracerebral hemorrhage (ICH) patients, and analyzed protein adsorption to the membranes using two-dimensional gel electrophoresis (2-DE) in combination with nano-liquid mass spectrometry. We compared the proteome profile of three compartments; the CMD membrane, the microdialysate and ventricular CSF collected at time of CMD removal. Results We found unique protein patterns in the molecular weight range of 10-35 kDa for each of the three compartments. Conclusion This study highlights the importance of analyzing the membranes in addition to the microdialysate when using CMD to sample proteins for biomarker investigation.Funding Agencies|Swedish Stroke Association (STROKE-Riksforbundet); County Council of Ostergotland (ALF); Linkoping University</p

A number of public or industrial buildings next to two water towers

https://commons.lib.jmu.edu/garber11/1110/thumbnail.jp

Plasma proteins from several components of the immune system differentiate chronic widespread pain patients from healthy controls - an exploratory case-control study combining targeted and non-targeted protein identification

Chronic widespread pain (CWP), including fibromyalgia (FM), is characterized by generalized musculoskeletal pain and hyperalgesia. Plasma proteins from proteomics (non-targeted) and from targeted inflammatory panels (cytokines/chemokines) differentiate CWP/FM from controls. The importance of proteins obtained from these two sources, the protein-protein association network, and the biological processes involved were investigated. Plasma proteins from women with CWP (n = 15) and CON (n = 23) were analyzed using two-dimensional gel electrophoresis analysis and a multiplex proximity extension assay for analysis of cytokines/chemokines. Associations between the proteins and group were multivarietly analyzed. The protein-protein association network and the biological processes according to the Gene Ontology were investigated. Proteins from both sources were important for group differentiation; the majority from the two-dimensional gel electrophoresis analysis. 58 proteins significantly differentiated the two groups (R-2 = 0.83). A significantly enriched network was found; biological processes were acute phase response, complement activation, and innate immune response. As with other studies, this study shows that plasma proteins can differentiate CWP from healthy subjects. Focusing on cytokines/chemokines is not sufficient to grasp the peripheral biological processes that maintain CWP/FM since our results show that other components of the immune and inflammation systems are also highly significant

Significant correlation between plasma proteome profile and pain intensity, sensitivity, and psychological distress in women with fibromyalgia

Fibromyalgia (FM) is a complex pain condition where the pathophysiological and molecular mechanisms are not fully elucidated. The primary aim of this study was to investigate the plasma proteome profile in women with FM compared to controls. The secondary aim was to investigate if plasma protein patterns correlate with the clinical variables pain intensity, sensitivity, and psychological distress. Clinical variables/background data were retrieved through questionnaires. Pressure pain thresholds (PPT) were assessed using an algometer. The plasma proteome profile of FM (n=30) and controls (n=32) was analyzed using two-dimensional gel electrophoresis and mass spectrometry. Quantified proteins were analyzed regarding group differences, and correlations to clinical parameters in FM, using multivariate statistics. Clear significant differences between FM and controls were found in proteins involved in inflammatory, metabolic, and immunity processes. Pain intensity, PPT, and psychological distress in FM had associations with specific plasma proteins involved in blood coagulation, metabolic, inflammation and immunity processes. This study further confirms that systemic differences in protein expression exist in women with FM compared to controls and that altered levels of specific plasma proteins are associated with different clinical parameters.Funding Agencies|Swedish Research CouncilSwedish Research Council [K2013-52X-22199-01-3, K2015-99x-21874-05-4, 521-2010-2,893, 2018-02,470]; Linkoping University</p

Systemic alterations in plasma proteins from women with chronic widespread pain compared to healthy controls: a proteomic study

Chronic widespread pain (CWP) is a complex pain condition that is difficult to treat. The prevalence of CWP approximates similar to 10% of the general population, with higher prevalence in women. Lack of understanding of molecular mechanisms has been a challenge for diagnosis and treatment of chronic pain. The aim of this study was to explore the systemic protein changes in CWP compared to those in healthy controls (CON). By applying 2-dimensional gel electrophoresis, we analyzed the protein pattern of plasma samples from women with CWP (n=16) and healthy women (n=23). The proteomic data were analyzed using multivariate statistical models, and altered proteins were identified using mass spectrometry. The proteome analysis was further validated by gel-free Western blot. Multivariate statistical data analysis of quantified proteins revealed 22 altered proteins in women with CWP, compared to CON group. Many of the identified proteins are previously known to be involved in different parts of the complement system and metabolic and inflammatory processes, e.g., complement factor B, vitamin D-binding protein, ceruloplasmin, transthyretin and alpha-2-HS-glycoprotein. These results indicate that important systemic protein differences exist between women with CWP and healthy women. Further, this study illustrates the potential use of proteomics to detect biomarkers that may provide new insights into the molecular mechanism(s) of chronic pain. However, further larger investigations are required in order to confirm these findings before it will be possible to identify proteins as potential pain biomarkers for clinical use.Funding Agencies|Swedish Council for Working Life and Social Research [2010-0913]; Swedish Research Council [K2015-99X-21874-05-04]; Medical Research Council of Southeast Sweden [159031]; AFA Insurance [Dnr-140341]; Region Ostergotland research fund [LIO445161, SC-2013-00395-36]; Ake Wiberg foundation</p