Quantifying 18kDa TSPO Expression in the Lung in Pulmonary Artery Hypertension (PAH)

Study Overview
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Brief Summary
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The aim of this study is to determine whether there is an increase in the TSPO PET signal (measured with the radioligand [11C]PBR28) in the lungs of patients living with PAH relative to age matched controls. If so, TSPO PET may be a useful technique to non-invasively monitor response to therapy. To do this, we will perform 2 [11C]PBR28 PET scans. The first will quantify the total [11C]PBR28 PET signal. This signal is a combination of the specific signal (VS) and the nonspecific signal (VND). The second scan will be performed following dosing with an unlabelled TSPO ligand. By directly measuring the total [11C]PBR28 signal (scan 1) and the nonspecific [11C]PBR28 signal (scan 2) we can therefore calculate the specific [11C]PBR28 signal, and hence the amount of TSPO in the lung.

Official Title
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Quantifying 18kDa TSPO Expression in the Lung in Pulmonary Artery Hypertension (PAH)

Conditions
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Pulmonary Arterial Hypertension, Healthy

Intervention / Treatment
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* Radiation: TSPO PET scan (11C-PBR28)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Able to provide written informed consent prior to any study mandated procedures. Able to lie comfortably on back for up to 90 minutes at a time. Fertile females (women of childbearing potential) are eligible to participate after a negative highly sensitive pregnancy test, if they are taking a highly effective method of contraception other than the oral contraceptive pill until the end of relevant systemic exposure. Male participants who are fertile are eligible to participate if they are willing to comply with the contraceptive requirements Exclusion Criteria: Unable to provide informed consent and/or are non-fluent speakers of the English language TT Genotype at the rs6971 locus Clinically-significant renal disease (confirmed by creatinine clearance <30 ml/min per 1.73m2) Clinically-significant liver disease (confirmed by serum transaminases >2 times than upper normal limit) Anaemia confirmed by haemoglobin concentration <10 g/dl Sickle cell disease or thalassaemia History of uncontrolled systemic hypertension Acute infection (including eye, dental, and skin infections) Chronic inflammatory disease including HIV, and Hepatitis B Women of childbearing potential who are pregnant or breastfeeding Patients who have received an Investigational Medicinal Product (IMP) within 5 half-lives of the last dose of the IMP or 1 month (which ever is greater) before the baseline visit Participation in a research study involving significant ionisation radiation within the last 3 years Significant radiation exposure other than dental X-rays in last 1 year Positive Allen's test. -

Ages Eligible for Study
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Minimum Age: 25 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| PAH<br> | Radiation: TSPO PET scan (11C-PBR28)<br>* PET scan<br>|
| Healthy volunteer<br> | Radiation: TSPO PET scan (11C-PBR28)<br>* PET scan<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The specific and non-specific fractions of the [11C]PBR28 signal in the lungs of healthy individuals and PAH patients. |  | 2 years |