Endogenous Opioid Systems and Symptom Change in Fibromyalgia

University of Utah

Overview

This study is designed to study brain mechanisms associated with symptoms and severity of Fibromyalgia. This will be accomplished by relating results from PET scans to self-reported and objective measures of disease severity.

The purpose of this study is to examine µ-opioid receptor (µOR)-mediated neurotransmission in patients diagnosed with persistent pain, fibromyalgia (FM), and its relationship with pain and affect measures. µOR activation is expected to take place in the following brain regions: rostral and dorsal anterior cingulate (rACC, dACC), orbitofrontal cortex (OFC), thalamus (THA), nucleus accumbens (NAC), amygdala (AMY), periaqueductal gray (PAG). Greater regional activation is expected to be associated with improvements in clinical pain ratings and affective state. The endogenous opioid system and µ-opioid receptors (µORs) play a central role in the regulation of pain, the pathophysiology of chronic pain syndromes, mood and emotion; this system is dysregulated in persistent pain syndromes. A substantial body of literature addressing these mechanisms has been developed in our laboratory, including recent data on the cognitive and molecular mechanisms associated with reductions in pain, as well as trait personality and genetic predictors of emotional effects in the context of pain. Eighty individuals who have been diagnosed with FM and who fit the inclusion and exclusion criteria will be enrolled in this 14-week protocol. An initial visit for informed consent procedures and baseline characterization will then be scheduled, as well as the visits for positron emission tomography (PET) and magnetic resonance imaging (MRI) procedures. Subjects will return for testing after 6 and 14 weeks. Volunteers will undergo imaging with structural and functional MRI and PET with \[11C\]carfentanil to determine baseline µOR non-displaceable binding potential (BPND) and changes in those BPND measures coinciding with symptom severity at the time of scanning.

Study Type

OBSERVATIONAL

Conditions

Fibromyalgia

Interventions

No treatmentOTHER

Observation

Eligibility

Sex: ALLMin age: 18 YearsMax age: 55 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Have met American College of Rheumatology (ACR) criteria for fibromyalgia for at least 1 year; * Willing to limit introduction of new treatments during the study; * Use of sleep aids no more than twice per week * 18-55 years of age * right handed * capable of providing written informed consent Exclusion Criteria: * concurrent untreated medical illnesses, autoimmune, or inflammatory disease; * Routine daily use of narcotic analgesics or history of substance abuse; * Concurrent participation in other therapeutic trials; * Pregnancy/ nursing; * Ongoing psychiatric illness; * Contraindications to PET or MRI methods; * Impairments that would prevent completion of the study protocol; * Use of sleep aids at frequency of more that twice per week; * Allergy to fentanyl

Outcomes

Primary Outcomes

change in mu opioid-mediated neurotransmission

assessed via PET scanning

Time frame: Change from baseline at 6 weeks

Secondary Outcomes

change in Biomarkers of pain response

serum cortisol

Time frame: Change from baseline at 6 weeks

change in Biomarkers of pain response

serum cortisol

Time frame: Change from 8 weeks at 14 weeks

change in Pain

assessed via questionnaire

Time frame: Change from baseline at 6 weeks

change in Pain

assessed via questionnaire

Time frame: Change from 8 weeks at 14 weeks

change in mu opioid-mediated neurotransmission

assessed via PET scanning

Time frame: Change from 8 weeks at 14 weeks

Data from ClinicalTrials.gov

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