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Here, we describe the development of an in‐house‐built device for the fully automated multistep synthesis of the cannabinoid CB1 receptor imaging tracer (3R,5R)‐5‐(3‐([18F]fluoromethoxy‐d2)phenyl)‐3‐(((R)‐1‐phenylethyl)amino)‐1‐(4‐(trifluoromethyl)phenyl)pyrrolidin‐2‐one ([18F]FMPEP‐d2), following good manufacturing practices. The device is interfaced to a HPLC and a sterile filtration unit in a clean room hot cell. The synthesis involves the nucleophilic 18F‐fluorination of an alkylating agent and its GC purification, the subsequent 18F‐fluoroalkylation of a precursor molecule, the semipreparative HPLC purification of the 18F‐fluoroalkylated product, and its formulation for injection. We have optimized the duration and temperature of the 18F‐fluoroalkylation reaction and addressed the radiochemical stability of the formulated product. During the past 5 years (2013–2018), we have performed a total of 149 syntheses for clinical use with a 90% success rate. The activity yield of the formulated product has been 1.0 ± 0.4 GBq starting from 11 ± 2 GBq and the molar activity 600 ± 300 GBq/μmol at the end of synthesis. [ABSTRACT FROM AUTHOR]

Here, we describe the development of an in‐house‐built device for the fully automated multistep synthesis of the cannabinoid CB1 receptor imaging tracer (3R,5R)‐5‐(3‐([18F]fluoromethoxy‐d2)phenyl)‐3‐(((R)‐1‐phenylethyl)amino)‐1‐(4‐(trifluoromethyl)phenyl)pyrrolidin‐2‐one ([18F]FMPEP‐d2), following good manufacturing practices. The device is interfaced to a HPLC and a sterile filtration unit in a clean room hot cell. The synthesis involves the nucleophilic 18F‐fluorination of an alkylating agent and its GC purification, the subsequent 18F‐fluoroalkylation of a precursor molecule, the semipreparative HPLC purification of the 18F‐fluoroalkylated product, and its formulation for injection. We have optimized the duration and temperature of the 18F‐fluoroalkylation reaction and addressed the radiochemical stability of the formulated product. During the past 5 years (2013–2018), we have performed a total of 149 syntheses for clinical use with a 90% success rate. The activity yield of the formulated product has been 1.0 ± 0.4 GBq starting from 11 ± 2 GBq and the molar activity 600 ± 300 GBq/μmol at the end of synthesis. [ABSTRACT FROM AUTHOR]

Activating brown adipose tissue (BAT) could provide a potential approach for the treatment of obesity and metabolic disease in humans. Obesity is associated with upregulation of the endocannabinoid system, and blocking the cannabinoid type 1 receptor (CB1R) has been shown to cause weight loss and to decrease cardiometabolic risk factors. These effects may be mediated partly via increased BAT metabolism, since there is evidence that CB1R antagonism activates BAT in rodents. To investigate the significance of CB1R in BAT function, we quantified the density of CB1R in human and rodent BAT using the positron emission tomography radioligand [18F]FMPEP-d2 and measured BAT activation in parallel with the glucose analog [18F]fluorodeoxyglucose. Activation by cold exposure markedly increased CB1R density and glucose uptake in the BAT of lean men. Similarly, β3-receptor agonism increased CB1R density in the BAT of rats. In contrast, overweight men with reduced BAT activity exhibited decreased CB1R in BAT, reflecting impaired endocannabinoid regulation. Image-guided biopsies confirmed CB1R mRNA expression in human BAT. Furthermore, CB1R blockade increased glucose uptake and lipolysis of brown adipocytes. Our results highlight that CB1Rs are significant for human BAT activity, and the CB1Rs provide a novel therapeutic target for BAT activation in humans. [ABSTRACT FROM AUTHOR]

Background Objective Methods Results Conclusions In Parkinson's disease (PD), postural instability and gait disorder (PIGD) symptoms are associated with a worse prognosis for an unknown reason.The objective was to explore the relationship between cannabinoid receptor type 1 (CB1R) availability and motor symptoms in PD with [18F]FMPEP‐d2 positron emission tomography (PET).Fifteen individuals with PD underwent [18F]FMPEP‐d2 PET to measure cerebral CB1R availability. The Unified Parkinson's Disease Rating Scale motor part (UPDRS‐III) was used to evaluate the motor symptoms.A negative correlation was observed between [18F]FMPEP‐d2 VT and PIGD score (P = 0.002) as well as rigidity subscore (P < 0.001). Both clusters covered widespread areas of both hemispheres. In contrast, tremor or bradykinesia did not correlate to [18F]FMPEP‐d2 VT.Gait, postural instability, and rigidity in PD are associated with decreased CB1R availability, unlike tremor or bradykinesia, suggesting that the endocannabinoid system has a role in the pathophysiology of different motor symptoms in PD. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]