Introduction

COVID-19 infection develops neurologic symptoms such as smell and taste loss. We aimed to determine the volumetric changes in the brain and correlation of possible related biochemical parameters and endocannabinoid levels after COVID-19 recovery.

Methods

Brain magnetic resonance images of recovered COVID-19 patients and healthy volunteers, whose olfactory and gustatory scores were obtained through a questionnaire, were taken, and the volumes of the brain regions associated with taste and smell were measured by automatic and semiautomatic methods. Endocannabinoids (EC), which are critical in the olfactory system, and vitamin B12, zinc, iron, ferritin, thyroid-stimulating hormone (TSH), and thyroxine (T4) levels, which are reported to have possible roles in olfactory disorders, were measured in peripheral blood.

Results

Taste and smell disorder scores and EC levels were found to be higher in recovered COVID-19 patients compared to controls. EC levels were negatively correlated with bilateral entorhinal cortex (ENT) volumes in the COVID-19 group. Subgenual anterior cingulate cortex volumes showed correlations with gustatory complaints and ferritin in recovered COVID-19 patients.

Conclusions

The critical finding of our study is the high EC levels and negative correlation between EC levels and left ENT volumes in recovered COVID-19 patients.

Implications

It is possible that ECs are potential neuromodulators in many conditions leading to olfactory disorders, including COVID-19.

中文翻译：

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内源性大麻素在 COVID-19 患者嗅觉和味觉功能障碍以及大脑体积变化中的可能作用

介绍

COVID-19 感染会出现神经系统症状，例如嗅觉和味觉丧失。我们的目的是确定 COVID-19 恢复后大脑的体积变化以及可能的相关生化参数和内源性大麻素水平的相关性。

方法

采集康复的 COVID-19 患者和健康志愿者的脑磁共振图像，其嗅觉和味觉评分通过问卷获得，并通过自动和半自动方法测量与味觉和嗅觉相关的大脑区域的体积。对嗅觉系统至关重要的内源性大麻素 (EC)，以及据报道可能在嗅觉障碍中发挥作用的维生素 B12、锌、铁、铁蛋白、促甲状腺激素 (TSH) 和甲状腺素 (T4) 水平在外周血中测量。

结果

与对照组相比，已康复的 COVID-19 患者的味觉和嗅觉障碍评分和 EC 水平更高。EC 水平与 COVID-19 组的双侧内嗅皮质 (ENT) 体积呈负相关。膝下前扣带皮层体积显示与康复的 COVID-19 患者的味觉不适和铁蛋白相关。

结论

我们研究的关键发现是恢复的 COVID-19 患者的高 EC 水平和 EC 水平与左耳鼻喉科体积之间的负相关。

启示

在许多导致嗅觉障碍（包括 COVID-19）的情况下，EC 可能是潜在的神经调节剂。