Smart Kelly, Cox Sylvia M L, Nagano-Saito Atsuko, Rosa-Neto Pedro, Leyton Marco, Benkelfat Chawki
Department of Psychiatry, McGill University, 1033 Pine Ave W, Montreal, Quebec, H3A 1A1, Canada.
Department of Neurology and Neurosurgery, McGill University, Montreal Neurological Institute, 3801 University Ave, Montreal, Quebec, H3A 2B4, Canada.
Synapse. 2018 Sep;72(9):e22041. doi: 10.1002/syn.22041. Epub 2018 Jul 20.
[ C]ABP688 is a positron emission tomography (PET) radioligand that binds selectively to metabotropic glutamate type 5 receptors (mGluR5). The use of this tracer has identified receptor binding changes in clinical populations, and has been informative in drug occupancy studies. However, previous studies have found significant increases in [ C]ABP688 binding in the later scan of same-day comparisons, and estimates of test-retest reliability under consistent scanning conditions are not available. The objective of this study was to assess the variability of [ C]ABP688 binding in healthy people in scans performed at the same time of day. Two [ C]ABP688 scans were acquired in eight healthy volunteers (6 women, 2 men) using a high-resolution research tomograph (HRRT). Scans were acquired 3 weeks apart with start times between 10:00am and 1:30pm. Mean mGluR5 binding potential (BP ) values were calculated across cortical, striatal and limbic brain regions. Participants reported on subjective mood state after each scan and blood samples were drawn for cortisol analysis. No significant change in BP between scans was observed. Variability in BP values of 11-21% was observed across regions, with the greatest change in the hippocampus and amygdala. Reliability was low to moderate. BP was not statistically related to scan start time, subjective anxiety, serum cortisol levels, or menstrual phase in women. Overall, [ C]ABP688 BP estimates show moderate variability in healthy people. Reliability is fair in cortical and striatal regions, and lower in limbic regions. Future research using this ligand should account for this in study design and analysis.
[碳]-ABP688是一种正电子发射断层扫描（PET）放射性配体，它能选择性地与代谢型谷氨酸受体5（mGluR5）结合。使用这种示踪剂已确定了临床人群中受体结合的变化，并在药物占据研究中提供了有用信息。然而，先前的研究发现，在同日比较的后期扫描中，[碳]-ABP688的结合有显著增加，并且在一致的扫描条件下重测信度的估计不可用。本研究的目的是评估在一天中同一时间进行扫描的健康人群中[碳]-ABP688结合的变异性。使用高分辨率研究断层扫描仪（HRRT）对8名健康志愿者（6名女性，2名男性）进行了两次[碳]-ABP688扫描。扫描间隔3周，开始时间在上午10:00至下午1:30之间。计算了皮质、纹状体和边缘脑区的平均mGluR5结合潜能（BP）值。每次扫描后，参与者报告主观情绪状态，并采集血样进行皮质醇分析。两次扫描之间未观察到BP有显著变化。各区域BP值的变异性在11%-21%之间，海马体和杏仁核的变化最大。信度为低到中度。BP与扫描开始时间、主观焦虑、血清皮质醇水平或女性月经周期无统计学关联。总体而言，[碳]-ABP688的BP估计值在健康人群中显示出中等变异性。皮质和纹状体区域的信度尚可，边缘区域的信度较低。未来使用这种配体的研究应在研究设计和分析中考虑到这一点。
