2018年1月15日,国际学术权威刊物自然出版集团旗下脑科学领域国际顶级期刊《Nature Neuroscience》杂志在线发表了美国威尔康奈尔医学院Costantino Iadecola研究员的一篇研究论文,研究报道了高盐饮食会影响大脑健康,导致肠道免疫系统发生变化,进而引发认知功能缺陷,而改变生活方式可能扭转这一结果。
已知高盐饮食会导致人类血压升高,增加患心血管疾病的风险。在细胞层面,过度的盐摄入会导致内皮细胞(覆盖血管的内表面,调节血管张力)功能异常,但是这种功能异常对于不同器官的长期影响一直以来并不清楚。
研究团队此次让小鼠摄入高盐饮食——与部分人类饮食中的高盐程度比例相当。几周后,小鼠内皮细胞出现功能异常,脑血流量减少,并且在多个行为测试中表现出认知受损,但是血压没有变化。高盐饮食也增加了小鼠肠道内TH17白血细胞的数量,并提高了这些细胞所释放的一种促炎症分子(IL-17)水平。研究人员发现,正是血流中IL-17的增加导致高盐饮食对脑血管功能和行为造成了负面影响。
虽然这些都是根据小鼠实验得出的结果,但是也表明IL-17能以类似方式影响人类脑血管内皮细胞,这意味着,高盐饮食可能对人类脑健康造成负面影响。值得注意的是,小鼠回归正常饮食或通过药物干预,可以逆转高盐饮食的后果,即改变生活方式或研发新型处方药,有望预防或帮助逆转相关后果。
原文链接:
Dietary salt promotes neurovascular and cognitive dysfunction through a gut-initiated TH17 response
原文摘要:
A diet rich in salt is linked to an increased risk of cerebrovascular diseases and dementia, but it remains unclear how dietary salt harms the brain. We report that, in mice, excess dietary salt suppresses resting cerebral blood flow and endothelial function, leading to cognitive impairment. The effect depends on expansion of TH17 cells in the small intestine, resulting in a marked increase in plasma interleukin-17 (IL-17). Circulating IL-17, in turn, promotes endothelial dysfunction and cognitive impairment by the Rho kinase–dependent inhibitory phosphorylation of endothelial nitric oxide synthase and reduced nitric oxide production in cerebral endothelial cells. The findings reveal a new gut–brain axis linking dietary habits to cognitive impairment through a gut-initiated adaptive immune response compromising brain function via circulating IL-17. Thus, the TH17 cell–IL-17 pathway is a putative target to counter the deleterious brain effects induced by dietary salt and other diseases associated with TH17 polarization.