PET Quantification in Healthy Humans of Cyclooxygenase-2, a Potential Biomarker of Neuroinflammation.

Cyclooxygenase-2 (COX-2) is present in a healthy brain at low densities but can be markedly upregulated by excitatory input and by inflammogens. This study evaluated the sensitivity of the PET radioligand [C]-6-methoxy-2-(4-(methylsulfonyl)phenyl)--(thiophen-2-ylmethyl)pyrimidin-4-amine ([C]MC1) to detect COX-2 density in a healthy human brain. The specificity of [C]MC1 was confirmed using lipopolysaccharide-injected rats and transgenic mice expressing the human gene, with 120-min baseline and blocked scans using COX-1 and COX-2 selective agents.

Development and Evaluation in Rat and Monkey of a Candidate Homochiral Radioligand for PET Studies of Brain Receptor Interacting Protein Kinase 1: [F]()-1-(5-(3-Fluorophenyl)-4,5-dihydro-1-pyrazol-1-yl)-2,2-dimethylpropan-1-one.

Receptor interacting protein kinase 1 (RIPK1) crucially upregulates necroptosis and is a key driver of inflammation. An effective PET radioligand for imaging brain RIPK1 would be useful for further exploring the role of this enzyme in neuroinflammation and for assisting drug discovery. Here, we report our progress on developing a PET radioligand for RIPK1 based on the phenyl-1-dihydropyrazole skeleton of a lead RIPK1 inhibitor, GSK'963.

[F]SF51, a novel F-labeled PET radioligand for translocator protein 18kDa (TSPO) in brain, works well in monkeys but fails in humans.

[F]SF51 is a novel radioligand for imaging translocator protein 18 kDa (TSPO) that previously displayed excellent imaging properties in nonhuman primates. This study assessed its performance in human brain and its dosimetry. Seven healthy participants underwent brain PET imaging to measure TSPO binding using a two-tissue compartment model (2TCM) to calculate total distribution volume ().