Identification and In Vitro and In Vivo Characterization of KAC-50.1 as a Potential α-Synuclein PET Radioligand.

The accumulation of aggregated α-synuclein (α-syn) is a pathological hallmark of Parkinson's disease (PD) and other synucleinopathies. Here within, we report the in vitro characterization targeting site 2 of α-syn fibrils and in vivo evaluation of NHPs of KAC-50.1 as a potential α-syn positron emission tomography (PET) radioligand.

Imaging the 5-HT receptor with PET: Evaluation of 5-HT and 5-HT affinity of pimavanserin in the primate brain.

Two complimentary techniques were used to estimate occupancy of pimavanserin (a selective 5-HT inverse agonist) to 5-HT and 5-HT receptors in non-human primate brains. One employed the 5-HT selective radioligand [C]CIMBI-36 combined with quantification of binding potentials in brain regions known to be enriched in 5-HT (cortex) or 5-HT (choroid plexus) receptors to estimate occupancy. Pimavanserin was 6-10 fold more potent displacing [C]CIMBI-36 from cortex (ED = 0.

Labeling of Bruton's Tyrosine Kinase (BTK) Inhibitor [C]BIO-2008846 in Three Different Positions and Measurement in NHP Using PET.

Bruton's tyrosine kinase (BTK) is pivotal in B-cell signaling and a target for potential anti-cancer and immunological disorder therapies. Improved selective reversible BTK inhibitors are in demand due to the absence of direct BTK engagement measurement tools. Promisingly, PET imaging can non-invasively evaluate BTK expression.

Evaluating the effect of rapamycin treatment in Alzheimer's disease and aging using in vivo imaging: the ERAP phase IIa clinical study protocol.

Background: Rapamycin is an inhibitor of the mechanistic target of rapamycin (mTOR) protein kinase, and preclinical data demonstrate that it is a promising candidate for a general gero- and neuroprotective treatment in humans. Results from mouse models of Alzheimer's disease have shown beneficial effects of rapamycin, including preventing or reversing cognitive deficits, reducing amyloid oligomers and tauopathies and normalizing synaptic plasticity and cerebral glucose uptake. The "Evaluating Rapamycin Treatment in Alzheimer's Disease using Positron Emission Tomography" (ERAP) trial aims to test if these results translate to humans through evaluating the change in cerebral glucose uptake following six months of rapamycin treatment in participants with early-stage Alzheimer's disease.

High Contrast PET Imaging of Subcortical and Allocortical Amyloid-β in Early Alzheimer's Disease Using [11C]AZD2184.

Background: Deposits of amyloid-β (Aβ) appear early in Alzheimer's disease (AD).

Objective: The aim of the present study was to compare the presence of cortical and subcortical Aβ in early AD using positron emission tomography (PET).

Methods: Eight cognitively unimpaired (CU) subjects, 8 with mild cognitive impairment (MCI) and 8 with mild AD were examined with PET and [11C]AZD2184.

Parametric and non-parametric Poisson regression for modelling of the arterial input function in positron emission tomography.

Full quantification of Positron Emission Tomography (PET) requires an arterial input function (AIF) for measurement of certain targets, or using particular radiotracers, or for the quantification of specific outcome measures. The AIF represents the measurement of radiotracer concentrations in the arterial blood plasma over the course of the PET examination. Measurement of the AIF is prone to error as it is a composite measure created from the combination of multiple measurements of different samples with different equipment, each of which can be sources of measurement error.

Development of a PET Tracer for OGA with Improved Kinetics in the Living Brain.

-GlcNAcylation is thought to play a role in the development of tau pathology in Alzheimer's disease because of its ability to modulate tau's aggregation propensity. -GlcNAcylation is regulated by 2 enzymes: -GlcNAc transferase and -GlcNAcase (OGA). Development of a PET tracer would therefore be an essential tool for developing therapeutic small-molecule inhibitors of OGA, enabling clinical testing of target engagement and dose selection.

Development of a Novel [C]CO-Labeled Positron Emission Tomography Radioligand [C]BIO-1819578 for the Detection of -GlcNAcase Enzyme Activity.

Imaging -GlcNAcase OGA by positron emission tomography (PET) could provide information on the pathophysiological pathway of neurodegenerative diseases and important information on drug-target engagement and be helpful in dose selection of therapeutic drugs. Our aim was to develop an efficient synthetic method for labeling BIO-1819578 with carbon-11 using CO for evaluation of its potential to measure levels of OGA enzyme in non-human primate (NHP) brain using PET. Radiolabeling was achieved in one-pot via a carbon-11 carbonylation reaction using [C]CO.

Design and Evaluation of [F]CHDI-650 as a Positron Emission Tomography Ligand to Image Mutant Huntingtin Aggregates.

Therapeutic interventions are being developed for Huntington's disease (HD), a hallmark of which is mutant huntingtin protein (mHTT) aggregates. Following the advancement to human testing of two [C]-PET ligands for aggregated mHTT, attributes for further optimization were identified. We replaced the pyridazinone ring of CHDI-180 with a pyrimidine ring and minimized off-target binding using brain homogenate derived from Alzheimer's disease patients.

Synthesis and Preclinical Evaluation of [C]AZ11895530 for PET Imaging of the Serotonin 1A Receptor.

The serotonin 1A (5-HT) receptor is a G-protein-coupled receptor implicated in the pathophysiology of several neuropsychiatric and neurodegenerative disorders. We here report the preparation of two candidate 5-HT radioligands, [C]AZ11132132 ([C]) and [C]AZ11895530 ([C]), and their subsequent evaluation using autoradiography and using positron emission tomography (PET). Compounds and were radiolabeled at high radiochemical purity (>99%) and high molar activity (>38 GBq/μmol) by heteroatom methylation with [C]methyl iodide.

[C]CHDI-626, a PET Tracer Candidate for Imaging Mutant Huntingtin Aggregates with Reduced Binding to AD Pathological Proteins.

The expanded polyglutamine-containing mutant huntingtin (mHTT) protein is implicated in neuronal degeneration of medium spiny neurons in Huntington's disease (HD) for which multiple therapeutic approaches are currently being evaluated to eliminate or reduce mHTT. Development of effective and orthogonal biomarkers will ensure accurate assessment of the safety and efficacy of pharmacologic interventions. We have identified and optimized a class of ligands that bind to oligomerized/aggregated mHTT, which is a hallmark in the HD postmortem brain.

Objective and Subjective Sleep in Rheumatoid Arthritis and Severe Seasonal Allergy: Preliminary Assessments of the Role of Sickness, Central and Peripheral Inflammation.

Introduction: Disturbed sleep in inflammatory disorders such as allergy and rheumatoid arthritis (RA) is common and may be directly or indirectly related to disease processes, but has not been well characterized in these patient groups, especially not with objective methods.

Aim: The present study aimed to characterize objective and subjective sleep in patients with allergy or RA using sleep diaries, one-channel EEG and actigraphy. It also aimed to investigate if sleep measures were associated with central immune activation, assessed using translocator protein (TSPO) positron emission tomography, as well as cytokine markers of peripheral inflammation and disease-specific symptoms or general symptoms of sickness.