Department of Medicine B for Gastroenterology, Hepatology, Endocrinology and Clinical Infectiology, University Hospital Muenster, Albert-Schweitzer-Campus 1, 48149 Muenster, Germany.
Center for Laboratory Medicine, University Hospital Muenster, 48149 Muenster, Germany.
Nutrients. 2022 May 10;14(10):2007. doi: 10.3390/nu14102007.
The SARS-CoV-2 virus is the causative agent of the COVID-19 pandemic. The disease causes respiratory failure in some individuals accompanied by marked hyperinflammation. Vitamin A (syn. retinol) can exist in the body in the storage form as retinyl ester, or in the transcriptionally active form as retinoic acid. The main function of retinol binding protein 4 (RBP4), synthesized in the liver, is to transport hydrophobic vitamin A to various tissues. Vitamin A has an important role in the innate and acquired immune system. In particular, it is involved in the repair of lung tissue after infections. In viral respiratory diseases such as influenza pneumonia, vitamin A supplementation has been shown to reduce mortality in animal models. In critically ill COVID-19 patients, a significant decrease in plasma vitamin A levels and an association with increased mortality have been observed. However, there is no evidence on RBP4 in relation to COVID-19. This prospective, multicenter, observational, cross-sectional study examined RBP4 (enzyme-linked immunosorbent assay) and vitamin A plasma levels (high-performance liquid chromatography) in COVID-19 patients, including 59 hospitalized patients. Of these, 19 developed critical illness (ARDS/ECMO), 20 developed severe illness (oxygenation disorder), and 20 developed moderate illness (no oxygenation disorder). Twenty age-matched convalescent patients following SARS-CoV-2 infection, were used as a control group. Reduced RBP4 plasma levels significantly correlated with impaired liver function and elevated inflammatory markers (CRP, lymphocytopenia). RBP4 levels were decreased in hospitalized patients with critical illness compared to nonpatients (p < 0.01). In comparison, significantly lower vitamin A levels were detected in hospitalized patients regardless of disease severity. Overall, we conclude that RBP4 plasma levels are significantly reduced in critically ill COVID-19 patients during acute inflammation, and vitamin A levels are significantly reduced in patients with moderate/severe/critical illness during the acute phase of illness.
严重急性呼吸综合征冠状病毒 2 型（SARS-CoV-2）是 COVID-19 大流行的病原体。这种疾病会导致一些个体出现呼吸衰竭，并伴有明显的过度炎症反应。维生素 A（也称为视黄醇）以视黄酯的储存形式或转录活性形式视黄酸的形式存在于体内。肝脏合成的视黄醇结合蛋白 4（RBP4）的主要功能是将疏水性维生素 A 转运到各种组织中。维生素 A 在先天和获得性免疫系统中具有重要作用。特别是，它参与感染后肺组织的修复。在流感肺炎等病毒性呼吸道疾病中，已证明维生素 A 补充可降低动物模型的死亡率。在危重症 COVID-19 患者中，观察到血浆维生素 A 水平显著降低，并与死亡率增加相关。然而，关于 COVID-19 与 RBP4 之间的关系尚无证据。这项前瞻性、多中心、观察性、横断面研究检测了 COVID-19 患者（包括 59 名住院患者）的 RBP4（酶联免疫吸附测定）和维生素 A 血浆水平（高效液相色谱法）。其中，19 例发展为危重症（急性呼吸窘迫综合征/体外膜氧合），20 例发展为重症（氧合障碍），20 例发展为中度疾病（无氧合障碍）。20 例年龄匹配的 SARS-CoV-2 感染后康复患者作为对照组。结果显示，RBP4 血浆水平降低与肝功能受损和炎症标志物（CRP、淋巴细胞减少）升高显著相关。与非患者相比，危重症住院患者的 RBP4 水平降低（p < 0.01）。相比之下，无论疾病严重程度如何，住院患者的维生素 A 水平均显著降低。总的来说，我们的结论是，在急性炎症期间，危重症 COVID-19 患者的 RBP4 血浆水平显著降低，在疾病急性阶段，中度/重度/危重症患者的维生素 A 水平显著降低。
