Gallbladder cancer is one of the most lethal carcinomas and continues to pose many challenges for surgeons. Identifiable risk factors for carcinoma of the gallbladder include cholelithiasis, an anomalous pancreaticobiliary junction, and focal mucosal microcalcifications. Adenocarcinoma is the primary histologic type in most patients and the tumor is frequently associated with Kras and p53 mutations. Radiologic and endoscopic advances in endoscopic ultrasonography and magnetic resonance cholangiopancreatogram, plus helical computed tomography, have enhanced preoperative staging. Surgical options include cholecystectomy for disease limited to the mucosa (Tis/T1) or a radical cholecystectomy (subsegmental resection of segments IVB and V plus a hepatoduodenal ligament lymphadenectomy) for advanced disease without signs of distant metastasis (T2-4/N0-N2). Some surgeons have advocated more radical hepatic resection including extended right hepatectomy or central bisegmentectomy plus caudate lobectomy. Japanese surgeons have reported studies that included patients having a pancreaticoduodenectomy to improve distal ductal margins and lymphadenectomy for T3 and T4 cancers. These patients have a lower rate of local recurrence but no survival advantage. Options for adjuvant therapy remain limited. Radiation therapy with fluorouracil radiosensitization is the most commonly used postoperative treatments. Current trials are investigating the role of capecitabine, oxaliplatin, and bevacizumab in the management of gallbladder carcinoma.

Organ graft preservation injury is a major problem complicating liver transplantation. The L-arginine/nitric oxide pathway has protective effects in several models of liver injury. The purpose of this study was to evaluate the role of the L-arginine/NO synthase (NOS) pathway on liver preservation injury and to characterize endogenous inducible NOS (iNOS) expression. Orthotopic liver transplantation was performed with 18-hour University of Wisconsin preservation solution in syngeneic rats. Recipient rats were either untreated or treated with L-arginine, D-arginine, nonspecific NOS inhibitor N G -nitro-L-arginine methyl ester (L-NAME), or iNOS selective inhibitor L-N 6 -(1-imino-ethyl)lysine (L-NIL) after revascularization. As early as 1 hour following reperfusion, circulating arginine levels decreased 10-fold and ornithine levels increased 4-fold. A corresponding increase in arginase I protein was detected in serum. To address the profound arginine deficiency, we supplemented recipients with arginine after transplantation. L-arginine (but not D-arginine) supplementation significantly reduced preservation injury 12 hours after reperfusion, suggesting that the protective effect of L-arginine was mediated through the generation of NO. iNOS protein expression peaked in the liver 6 to 12 hours following reperfusion. Blockade of the L-arginine/NO pathway with L-NAME significantly increased necrotic and apoptotic cell death in the transplanted graft. Addition of the iNOS selective inhibitor L-NIL mildly increased liver transaminase levels and also increased apoptosis in the liver graft. In conclusion, transplant recipients are profoundly arginine deficient postreperfusion due to arginase release. L-Arginine supplementation and NO synthesis decrease necrotic and apoptotic cell death and ameliorate liver transplant preservation injury. (HEPATOLOGY 2002;36:573-581.)

No abstract

Liver ischemia-reperfusion (I/R) injury is associated with profound arginine depletion due to arginase release from injured hepatocytes. The purpose of this study was to determine whether arginase inhibition with N -hydroxy-nor-L-arginine (nor-NOHA) would increase circulating arginine levels and decrease hepatic damage during liver I/R injury. The effects of nor-NOHA were initially tested in normal animals to determine in vivo toxicity. In the second series of experiments, orthotopic syngeneic liver transplantation (OLT) was performed after 18 h of cold ischemia time in Lewis rats. Animals were given nor-NOHA (100 mg/kg) or saline before and after graft reperfusion. In normal animals treated with nor-NOHA, there were no histopathological changes to organs, liver enzymes, serum creatinine, or body weight. In the OLT model, animals treated with saline exhibited markedly elevated serum transaminases and circulating arginase protein levels. Nor-NOHA administration blunted the increase in serum arginase activity by 80% and preserved serum arginine levels at 3 h after OLT. Nor-NOHA treatment reduced post-OLT serum liver enzyme release by 50%. Liver histology (degree of necrosis) in nor-NOHA-treated animals was markedly improved compared with the saline-treated group. Furthermore, use of the arginase inhibitor nor-NOHA did not influence polyamine synthesis owing to the decrease in ornithine levels. Arginase blockade represents a potentially novel strategy to combat hepatic I/R injury associated with liver transplantation. liver transplantation; arginine; nitric oxide; preservation injury ISCHEMIA-REPERFUSION (I/R) injury is a pathophysiological process whereby hypoxic organ damage is accentuated following return of blood flow and oxygen delivery to the compromised tissue. Transient episodes of hepatic ischemia occur during solid organ transplantation, trauma, hypovolemic shock, and elective liver resection, when inflow occlusion or total vascular exclusion is used to minimize blood loss. The pathophysiology of liver I/R injury includes both direct cellular damage as the result of the ischemic insult as well as delayed dysfunction and damage resulting from activation of inflammatory pathways (3,6,8,21,26,29). The injury that results from I/R after liver transplantation contributes to primary nonfunction in ϳ5-10% of liver grafts and delayed graft function in 15-30% of cases (9, 30).Nitric oxide (NO) is known to have an important role in regulating liver physiology and blood flow. NO and citrulline are produced by the family of nitric oxide synthases (NOS) from the substrate L-arginine (32). NO has been shown to exert protective effects in the liver by improving blood flow, antagonizing neutrophil activation and adhesion, neutralizing free radical injury, and eliciting antiapoptotic effects (19, 23). The beneficial effects of the L-arginine-NO pathway have also been reported in liver transplantation models. Experiments using arginine supplementation and NO donors have shown that NO serves to improve liver ischemia injury...

The human iNOS (hiNOS) gene is expressed in a tissue-specific manner, but the molecular basis for this regulation has not been elucidated. Here, we show that liver cell-specific hiNOS gene activation involves protein-DNA binding to an A-activator binding site (AABS) located at -192 nucleotides in the hiNOS promoter region. Mutation of this site in the -7.2 kb hiNOS promoter construct inhibited basal hiNOS promoter activity in primary rat hepatocytes (77%), and two human liver cell lines, AKN-1 (63%) and HepG2 (60%), but had no significant effect on basal hiNOS activity in three non-hepatic human cell types. Interestingly, mutation of AABS significantly abrogated cytokine-induced promoter activity in all cell types. C/EBPbeta transcription factor bound to AABS by gel shift assay. Overexpression of C/EBPbeta active form (LAP) increased hiNOS basal promoter activity approximately sixfold in liver cells, but had minimal effect in non-hepatic cells. In contrast, overexpression of the transcriptional inhibitor (LIP) strongly suppressed both basal and cytokine-inducible promoter activity. These data show that the cis-acting AABS DNA element mediates liver-specific basal hiNOS promoter activity through binding of the trans-acting C/EBPbeta factor. Further, C/EBPbeta binding to AABS functions as a "switchpoint" that is necessary for cytokine-inducible hiNOS gene expression in all cell types examined.