急性肝不全(ALF)を中心として各種肝疾患において,血管内皮細胞の障害のマーカーであるThrombomodulin (TM)を測定し,臨床的意義を検討した.急性肝不全では,血清中TM濃度は急性肝炎に比し有意に上昇していた.また血清中TM濃度は血清クレアチニン濃度と有意の相関を示していた.そこで腎不全のない時点での急性肝疾患の血清中TM濃度を比較すると,やはり急性肝不全では,急性肝炎に比し有意に上昇していた.しかし播種性血管内凝固症候群(DIC)のマーカーであるトロンビン・アンチトロンビンIII複合体(Thrombin・Antithrombin III complex, TAT)とは相関はみられなかった.このことから,血清中TM濃度は急性肝不全の進展を把握するマーカーになりうると推定された.さらに今後,肝静脈血中のTMを測定しTATとの関連を検討することで,障害発現のメカニズムを解明していく必要があると考えられた.
A choline-deficient L-amino acid-defined (CDAA) diet led to the development of liver cirrhosis in 100% of male Wistar rats after 16 weeks. In contrast, an ordinary (semipurified) choline-deficient (CD) diet led to the development of liver cirrhosis in only 33.3%. After 16 weeks, the liver hydroxyproline content, which reflects the amount of collagen, increased to a level more than four times higher in rats fed a CDAA diet than in rats fed a choline-supplemented L-amino acid-defined (CSAA) diet. Concurrent administration of a prolyl 4-hydroxylase inhibitor, 2,4-pyridine dicarboxylic acid bis(2-methoxyethyl amide) (HOE 077), to rats fed a CDAA diet reduced this increase in liver hydroxyproline content in a dose-dependent manner for doses up to 200 p.p.m. Microscopically, reduction in the hydroxyproline content of the liver resulted in a reduced number of pseudolobuli and thinner fibrous septa. HOE 077 showed no effect on liver hydroxyproline content in rats fed a CSAA diet. The administration of a CDAA diet for 16 weeks led to a substantial induction of GSTP-positive lesions in the liver. The concurrent administration of HOE 077 reduced the number, average diameter and percent area of GSTP-positive lesions in a dose-dependent manner, in parallel with the reduction in hydroxyproline content. These data suggest that inhibition of fibrosis may limit the development of subsequent neoplasms.
Although recent studies suggest the inhibitory property of N-acetyl-L-cysteine (NAC) on activation of hepatic stellate cell (HSC), the effects on once-activated HSCs are not well clarified. We investigated the influences of NAC on human-derived once-activated HSC line, LI90 with a focus on the collagen alpha2 (I) (COL1A2) promoter expression. Plasmid containing whole length of COL1A2 promoter linked to firefly luciferase gene and its various 5'-deletions were transiently transfected to LI90. The luciferase activity was determined with or without 10 mM of NAC in the absence or presence of 1 ng/ml of transforming growth factor (TGF)-beta. The effects of NAC on generation of intracellular reactive oxygen species (ROS) in LI90 were also analyzed. As a result, NAC significantly (P<0.05) suppressed the COL1A2 promoter expression in the absence or presence of TGF-beta. The expression was much more inhibited when used the deletion containing only AP-1/NF-kappaB binding sites than that including only three SP-1 binding sites. The ROS production was also comparably inhibited by NAC in both condition. These results indicated NAC suppressed, through its anti-oxidative action, the COL1A2 promoter expression in once-activated HSCs in the absence or presence of TGF-beta at least partly by affecting the signal transduction cascade encompassing AP-1/NF-kappaB activation.
Abstract: Activated liver macrophages are considered to play an important role in the development of liver injuries. Functional differences between activated and normal rat liver macrophages were investigated. In addition, from the therapeutic point of view, the effects of prostaglandin E 1 , prostaglandin I 2 and E3330 ((2E)‐3‐[5‐(2,3‐dimethoxy‐6‐methyl‐1,4‐benzoquinoyl)]‐2‐nonyl‐2‐propenoic acid) on the functions of liver macrophages were also determined. Rat liver macrophages were primed by Propionibacterium acnes and activated by a small dose of lipopolysaccharide. Lipopolysaccharide uptake capacity was evaluated quantitatively by flow cytometric analysis. Tumor necrosis factor‐α activities were measured by bioassay. There were no significant differences in lipopolysaccharide uptake capacity between activated and normal liver macrophages, while activated liver macrophages had a significantly (P<0.01) higher capacity in the release of tumor necrosis factor‐α. Prostaglandin E 1 and E3330 inhibited tumor necrosis factor‐α release without suppressing lipopolysaccharide uptake capacity. In this study we have clarified the functional differences between activated and normal liver macrophages. The beneficial effects of prostaglandin E 1 and E3330 on the functions of liver macrophages were also demonstrated.
