Introduction

Glymphatic fluid circulation may be considered the lymphatic system of the brain and the main role of such system seems to be played by aquaporins (AQPs), a family of proteins which regulates water exchange, in particular AQP4 and 1. Alterations of glymphatic fluid circulation through AQPs variations are now emerging as central elements in the pathophysiology of different brain conditions, like hydrocephalus. This systematic review provides an insight about the role of AQPs in hydrocephalus establishment and compensation, investigating their possible role as diagnostic tools or therapeutic targets.

Methods

PubMed database was screened searching for the relevant existing literature in English language published until February 29th 2020, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement.

Results

A total of 40 articles met the inclusion criteria for our systematic analysis. AQP4 resulted the most studied water channel, followed by AQP1. The changes in cerebrospinal fluid (CSF), brain parenchyma and choroid plexus (CP) in different hydrocephalus type were analyzed. Moreover, important pharmacological interactions regarding AQP and molecules or conditions were discussed. A very interesting result is the general consensus on increase of AQP4 in hydrocephalic patients, unless in patients suffering from idiopathic normal pressure hydrocephalus, where AQP4 shows a tendency in reduction.

Conclusion

AQP seem to play a central role in the pathophysiology of hydrocephalus and in its compensation mechanisms. Further studies are required to definitively establish their precise roles and their quantitative changes to allow their utilization as diagnostic tools or therapeutic targets.

中文翻译：

---

水通道蛋白在脑积水中的作用：我们知道什么，我们站在什么位置？系统评价。

介绍

淋巴液循环可以被认为是大脑的淋巴系统，这种系统的主要作用似乎是由水通道蛋白 (AQP) 发挥的，水通道蛋白是一个调节水交换的蛋白质家族，特别是 AQP4 和 1。 AQPs 变异现在正在成为不同脑部疾病（如脑积水）病理生理学的核心要素。这篇系统评价提供了关于 AQP 在脑积水形成和补偿中的作用的见解，研究了它们作为诊断工具或治疗目标的可能作用。

方法

根据系统评价和元分析的首选报告项目 (PRISMA) 声明，对 PubMed 数据库进行了筛选，以搜索截至 2020 年 2 月 29 日出版的相关现有英文文献。

结果

共有 40 篇文章符合我们系统分析的纳入标准。AQP4 是研究最多的水通道，其次是 AQP1。分析不同脑积水类型的脑脊液（CSF）、脑实质和脉络丛（CP）的变化。此外，还讨论了有关 AQP 和分子或条件的重要药理学相互作用。一个非常有趣的结果是脑积水患者中 AQP4 增加的普遍共识，除非在患有特发性正常压力脑积水的患者中，AQP4 显示出减少的趋势。

结论

AQP 似乎在脑积水的病理生理学及其代偿机制中起着核心作用。需要进一步的研究来明确确定它们的精确作用和它们的数量变化，以便将它们用作诊断工具或治疗目标。