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About
Background:
Inflammation plays a significant role in various disorders that involve neurodegeneration or autoimmune reaction as one of their mechanisms. PET scans can help detect inflammation. Two new drugs may create better PET images.
Objective:
- To see if the drug [11C]MC1 can help image inflammation.
Eligibility:
Design:
Full description
I. Objective
18-kDa translocator protein (TSPO) and cyclooxygenase-2 (COX-2) are both implicated in the pathophysiology of various inflammatory disorders, suggesting that both may serve as potential biomarkers of inflammation in brain as well as periphery. Our laboratory recently developed two new radioligands: [11C]ER176 to image TSPO and [11C]MC1 to image COX-2. Using wholebody imaging, this study seeks to determine whether PET imaging using these new radioligands can differentiate two inflammatory conditions-rheumatoid arthritis (RA) and idiopathic inflammatory myopathies (IIM)-from healthy conditions. To determine if [11C]MC1 uptake is specific to COX-2, we will also conduct a blocking study with a selective COX-2 inhibitor (celecoxib) in both [11C]MC1 and [11C]ER176 scans; celecoxib is expected to block uptake of [11C]MC1 but not [11C]ER176. Using brain-dedicated imaging, this seeks to determine whether RA patients and healthy volunteers have specific binding in brain - i.e., uptake that can be blocked celecoxib.
II. Study population
Healthy volunteers (n = 17), patients with RA (n = 15), and patients with IIM (n = 15) will undergo whole-body PET/CT scans. Patients with AxSpA (n=15) will undergo two whole-body PET/MRI scans. In addition, healthy volunteers (n = 22) and patients with RA (n = 12) will have brain-dedicated imaging using [11C]MC1 concurrent with arterial blood sampling. Finally, 15 patients with RA will be imaged during a period of moderate to severe symptoms and after clinically indicated treatment for two to four months. Thus, the entire population will be healthy volunteers (n = 39), patients with RA (n = 42), patients with AxSpA (n=15) and patients with
IIM (n = 15).
III. Design
IV. Outcome measures
For whole body imaging, radioligand uptake in a selected region of interest will be quantified as a Standardized Uptake Value (SUV), which normalizes for injected activity and body weight. Possible differences in actual blood radioligand level will be adjusted by venous blood data obtained during the PET scan. Regional uptake after blockade with celecoxib will be expressed as a percentage of the baseline value. The baseline uptake and the percentage blockade by celecoxib of each radioligand will be compared between patients and healthy subjects as well as between inflamed and non-inflamed regions of the body in RA and IIM patients.
For brain-dedicated imaging, the density of COX-2 will be measured with pharmacokinetic modeling and expressed as distribution volume (VT).
Enrollment
Sex
Ages
Volunteers
Inclusion and exclusion criteria
Healthy subjects
RA patients
IIM patients
Axial Spondyloarthritis (AxSpA) patients
EXCLUSION CRITERIA:
Common for all participants
These may include:
History of hypersensitivity reaction to COX inhibitors or History of aspirin- or NSAID-induced asthma
History of upper or lower gastrointestinal bleeding, gastritis, peptic ulcer disease
History of uncontrolled gastroesophageal reflux disease (GERD), but not medically controlled GERD
Coagulation disorder
Thrombocytopenia
Glucose-6-phosphate dehydrogenase (G6PD) deficiency
History of gout
History of hepatic or renal impairment
History of cardiovascular disease or presence of cardiovascular risk factors such as uncontrolled or poorly controlled hypertension
Current use of probenecid
Patients clinically in remission or who have low disease activity
Positive HIV infection
Any other history of severe medical illness or injury with the potential to affect study data interpretation or to be any medical contraindication to the procedures performed in the study, including active infection and untreated malignancy.
Unable to travel to NIH
Recent exposure to radiation related to research (e.g., PET from other research) that, when combined with this study, would be above the allowable limits.
Inability to lie flat on camera bed for at least two hours, including claustrophobia and overweight greater than the maximum for the scanner (500 lb.).
Pregnancy or breastfeeding.
Participants must not have substance use disorder or alcohol use disorder. However, alcohol or cannabis use by themselves are not exclusion criteria, unless that use affects the function of daily life.
NIMH employees or an NIH employee who is a subordinate/relative/co-worker of the investigators.
Healthy subjects
AxSpA and IIM patients
Primary purpose
Allocation
Interventional model
Masking
31 participants in 4 patient groups
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Central trial contact
Robert B Innis, M.D.; Tara N Turon, C.R.N.P.
Data sourced from clinicaltrials.gov
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