Mallory bodies are characteristic morphological features of alcoholic hepatitis in man and can be produced in the mouse by chronic griseofulvin intoxication. The appearance of Mallory bodies in hepatocytes is associated with derangement of the cytokeratin intermediate filament cytoskeleton, at least as revealed by immunofluorescence and suggested by immunoelectron microscopy. Immunohistochemical studies were performed to answer the question whether Mallory body formation and cytoskeleton alterations finally lead to cell death or are reversible phenomena. Chronically griseofulvin-intoxicated mice killed at different stages of recovery on a normal diet served as experimental animals. It could be shown that (a) Mallory bodies are very durable structures and are found for up to 6 mo after griseofulvin withdrawal as a result of persistence and neoformation; (b) new Mallory bodies can appear even several months after cessation of griseofulvin feeding; (c) Mallory body formation and cytoskeletal changes by themselves do not lead to irreversible cell damage; (d) the cytoskeletal changes are reversible within 7 mo after griseofulvin withdrawal; (e) a dissociation between disappearance of Mallory bodies and restoration of a regularly immunostained cytoplasmic cytokeratin meshwork is observed.

In order to investigate the mechanism of kinin release leading to vascular symptoms in acute interstitial‐oedematous pancreatitis, the novel, selective inhibitors of tissue kallikrein, (2S,2′R)‐2‐(2′‐amino‐3′‐(4′‐chlorophenyl)propanoylamino)‐N‐(3‐guanidinopropyl)‐3‐(1‐naphthyl)propanoamide (FE999024, CH‐2856), and of plasma kallikrein, (2′S,2′′R)‐4‐(2′‐(2′′(carboxymethylamino)‐3′′‐cyclohexyl‐propanoylamino)‐3′‐phenyl‐propanoylamino)piperidine‐1‐carboxamidin (FE999026, CH‐4215), were used in experimental caerulein‐induced pancreatitis in rats. Oedema formation and plasma protein extravasation during the 2 h infusion of caerulein were inhibited in a dose‐dependent manner by i.p. pretreatment with FE999024 (7–60 μmol kg−1) while FE999026 had no effect at the same doses. Haemoconcentration and hypovolaemia associated with the pancreatic oedema formation during pancreatitis were significantly attenuated by FE999024 at a dose of 20 μmol kg−1. The reduction in circulating plasma volume was not affected by FE999026. Accumulation of amylase and lipase in the pancreas was dose‐dependently reduced by FE999024 while enzyme activities in the blood serum were increased by FE999024 at 60 μmol kg−1 indicating improved enzyme removal from the tissue. Enzyme activities in the tissue and in the blood remained unaffected by FE999026. FE999024 (20 μmol kg−1) largely inhibited increased tissue kallikrein‐like activity in the pancreas during acute pancreatitis and also strongly attenuated influx of plasma kallikrein into the tissue. FE999026 (20 μmol kg−1) significantly inhibited plasma kallikrein‐like activity in the pancreas but had no effect on tissue kallikrein‐like activity. In conclusion, vascular kinin‐mediated symptoms observed during oedematous pancreatitis in the rat are caused by the action of tissue kallikrein in the pancreas whereas an involvement of plasma kallikrein seems to be unlikely. British Journal of Pharmacology (2002) 137, 692–700. doi:

1 Kinin B 2 receptor antagonists or tissue kallikrein (t-KK) inhibitors prevent oedema formation and associated sequelae in caerulein-induced pancreatitis in the rat. We have now further investigated the mechanism of kinin generation in the pancreas. 2 Kinins were elevated in the pancreatic tissue already before oedema formation became manifest. Peak values (421759 pmol g À1 dry wt) were reached at 45 min and remained elevated for at least 2 h; a second increase was observed at 24 h. Pretreatment with the B 2 receptor antagonist icatibant abolished kinin formation, while post-treatment was ineffective. 3 Total kininogen levels were very low in the pancreas of controls, but increased 75-fold during acute pancreatitis. This increase was absent in rats that were pretreated with icatibant. 4 During pancreatitis, t-KK-like and plasma kallikrein (p-KK)-like activity in the pancreas, as well as trypsinogen activation peptide (TAP) increased significantly. Icatibant pretreatment further augmented t-KK about 100-fold, while p-KK was significantly attenuated; TAP levels remained unaffected. 5 Endogenous protease inhibitors (a 1 -antitrypsin, a 2 -macroglobulin) were low in normal tissues, but increased 45-and four-fold, respectively, during pancreatitis. This increase was abolished when oedema formation was prevented by icatibant. 6 In summary, oedema formation is initiated by t-KK; the ensuing plasma protein extravasation supplies further kininogen and active p-KK to the tissue. Concomitantly, endogenous protease inhibitors in the oedema fluid inhibit up to 99% of active t-KK. Our data thus suggest a complex interaction between kinin action and kinin generation involving positive and negative feedback actions of the inflammatory oedema.

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