METHODS: 46 healthy subjects (mean age ± SD = 32.5 ± 10); sex (M/F) = 32/14)) underwent PET imaging with [11C]PBR28 in a retrospectively conducted analysis. All PET scans were performed on the HRRT scanner. Volume of distribution (VT) values were generated for cortical and subcortical regions and the cerebellum. Spring/summer months were defined as March to August while fall/winter months were defined as September to February and were compared through 2-tailed t-tests (SciPy library v.1.10.1 and Pinguoin library on Python v.3.8.8). Average daylight hours and temperature in New Haven, CT were obtained online (www.wunderground.com) and compared to VT with Spearman\'s correlations.
RESULTS: There were no significant differences observed between the TSPO levels of spring/summer and fall/winter months in the brain (t = 0.52, p = 0.61). Additional analysis on all individual brain regions also indicated non-significance. Likewise, no significant correlations were found between TSPO levels in the whole brain and brain regions against daylight hours (ρ= 0.05, p = 0.74), temperature (ρ = 0.04, p = 0.81), or month (ρ = 0.08, p = 0.60). Controlling TSPO gene polymorphisms and other variables had no significant effect on the outcome.
CONCLUSIONS: To the best of our knowledge, this is the first human study to investigate seasonal changes in TSPO expression. Our results can be interpreted as the lack of seasonal variability in the neuroimmune system, but important limitations include high interindividual variability, test-retest variability, specificity of the tracer, and a limited sample size. Limitations notwithstanding, our results conclude that TSPO levels in the brain are not impacted by light and temperature changes in different seasons.
方法:46名健康受试者(平均年龄±SD=32.5±10);性别(M/F)=32/14)接受了[11C]PBR28的PET成像。所有PET扫描均在HRRT扫描仪上进行。生成皮质和皮质下区域以及小脑的分布体积(VT)值。春季/夏季定义为3月至8月,而秋季/冬季定义为9月至2月,并通过双尾t检验进行比较(Python上的SciPy库v.1.10.1和Pinguoin库v.3.8.8)。纽黑文中的平均夏令时和温度,CT均在线获得(www。wunderground.com),并将VT与斯皮尔曼的相关性进行了比较。
结果:在大脑中春季/夏季和秋季/冬季的TSPO水平之间没有观察到显着差异(t=0.52,p=0.61)。对所有单个脑区域的额外分析也表明无显著性。同样,全脑和脑区的TSPO水平与白天小时数之间没有发现显著的相关性(ρ=0.05,p=0.74),温度(ρ=0.04,p=0.81),或月(ρ=0.08,p=0.60)。控制TSPO基因多态性和其他变量对结果没有显着影响。
结论:据我们所知,这是第一项调查TSPO表达季节性变化的人类研究。我们的结果可以解释为神经免疫系统缺乏季节性变化,但重要的限制包括高度的个体差异,测试-重测变异性,示踪剂的特异性,和有限的样本量。尽管有限制,我们的结果得出结论,大脑中的TSPO水平不受不同季节光照和温度变化的影响。