Department of Pharmacology and Toxicology, Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, United States.
World J Gastroenterol. 2020 Apr 28;26(16):1879-1887. doi: 10.3748/wjg.v26.i16.1879.
The liver functions, in part, to prevent exposure of the body to potentially harmful substances ingested in the diet. While it is highly efficient at accomplishing this, it is frequently prone to liver injury due to the biotransformation of xenobiotics into toxic metabolites. To counter this injury, the liver has evolved a unique capacity to rapidly and efficiently repair itself. Successful resolution of acute liver injury relies on hepatic macrophage populations that orchestrate the reparative response. After injury, Kupffer cells, the resident macrophages of the liver, become activated and secrete proinflammatory cytokines. These cytokines recruit other immune cells, including monocyte-derived macrophages, to the liver where they contribute to the repair process. Monocyte-derived macrophages traffic into the necrotic foci where they rapidly phagocytose dead cell debris. Simultaneous with this process, these cells change phenotype from a proinflammatory macrophage to a pro-restorative macrophage that produce pro-mitogenic growth factors and anti-inflammatory cytokines. Ultimately this process triggers resolution of inflammation, and along with proliferation of other hepatic cells, restores the liver architecture and function. While the mechanisms regulating specific macrophage functions during repair remain to be elucidated, recent studies indicate a key role for the fibrinolytic system in coordinating macrophage function during repair. In this review, we will highlight the function and role of hepatic macrophages in repair after acute liver injury, and will discuss the role of the fibrinolytic enzyme, plasmin, in regulation of these various processes.
肝脏的功能部分在于防止人体接触到饮食中摄入的潜在有害物质。尽管肝脏在完成这一任务时效率很高,但由于外源性物质转化为有毒代谢物,肝脏经常容易受到损伤。为了对抗这种损伤,肝脏已经进化出一种独特的快速而有效地自我修复的能力。急性肝损伤的成功解决依赖于肝脏巨噬细胞群来协调修复反应。损伤后,肝脏中的常驻巨噬细胞库普弗细胞被激活并分泌促炎细胞因子。这些细胞因子招募其他免疫细胞,包括单核细胞衍生的巨噬细胞,到肝脏,在那里它们有助于修复过程。单核细胞衍生的巨噬细胞迁移到坏死灶,迅速吞噬死亡细胞碎片。与此同时,这些细胞从促炎巨噬细胞转变为促修复巨噬细胞,产生促有丝分裂生长因子和抗炎细胞因子。最终,这个过程引发炎症的消退,伴随着其他肝细胞的增殖,恢复肝脏的结构和功能。虽然调节修复过程中特定巨噬细胞功能的机制仍有待阐明,但最近的研究表明,纤维蛋白溶解系统在协调修复过程中的巨噬细胞功能方面起着关键作用。在这篇综述中,我们将重点介绍肝脏巨噬细胞在急性肝损伤后的修复中的功能和作用,并讨论纤维蛋白溶解酶纤溶酶在调节这些各种过程中的作用。