Background: Liver injury during acute pancreatitis (AP) is a manifestation of a systemic inflammatory response and a clinical prognostic indicator. We have demonstrated that pancreatic elastase induces macrophage TNF production in distant organs thus mimicking pancreatitis-associated end organ injury.
Aim: To determine the mechanism by which elastase induces, and Gadolinium (Gd) modulates hepatic cytokine production and injury.
Methods: Rat livers were perfused in situ (n=40) for 60 min using elastase ± pretreatment with Gd (10mg/g IV, 2 days). Liver enzymes, TNF (ELISA), and O2 content were measured in the effluent. Lethal hepatocyte injury (LHI) was assessed by propidium iodide staining (non-viable cells/hpf). In vitro, TNF protein, mRNA (RT-PCR) and NF-kB activation (EMSA) were measured in tissue cultures of freshly isolated rat Kupffer cells (KC) treated with elastase (1U/ml)± pretreatment with Gd (0.5mg/ml). Data: mean ± SEM.
Results: Elastase induced hepatic TNF production and typical pancreatitis-associated liver injury (increased LHI, LDH, ALT: *p£0.03; Table, ALT data not shown). Pretreatment with Gd blunted the effect of elastase on all parameters including TNF (**p£0.03, Table). In-Vitro, elastase induced massive TNF production by KC. Gd significantly reduced TNF production without affecting KC viability (p£0.03,data not shown). Similarly, Gd significantly attenuated elastase-induced overexpression of TNF mRNA and NF-kB activation in KC (Figure: C: Control, El: Elastase, Gd).
Conclusion: Pancreatic elastase causes a pattern of liver injury similar to that seen during AP by activating KC TNF production. Gd attenuates elastase-induced liver injury by inhibiting KC TNF production via NF-kB. KC blockade by Gd may have therapeutic implications. Support: VA Merit Review (JN), Seed Grant (MM)
In situ Liver Perfusion Control Elastase Gd
LDH (u/L) 110±2 1016±436* 185±60**
LHI (cells/hpf) 45±20 220±26* 71±11**
TNF (ng/ml) 195±59 1238±297* 449±62**