Stephen J. Kovach

Role of cyclic-AMP responsive element binding (CREB) proteins in cell proliferation in a rat model of hepatocellular carcinoma

The role of cyclic adenosine monophosphate (cAMP) is poorly understood in the regulation of normal and abnormal hepatic cell growth. In this study, we examined the regulation of intracellular cAMP levels and its effect on nuclear cAMP responsive elements (CREs) in a rat model of hepatocellular carcinoma (HCC). Tumorigenic liver cells were cultured from an in vivo model of HCC and the role of cAMP in cell mitogenesis determined. These data demonstrated agents that elevate intracellular cAMP ([cAMP]i) levels caused significant dose‐dependent inhibition of serum‐stimulated mitogenesis in HCC cells. Cells were next analyzed for transcription factor expression and activity following increased [cAMP]i. These data demonstrated time‐ and dose‐dependent increases in CRE binding protein (pCREB) activity, a maximal response occurring after 10–20 min before returning to basal levels within 60 min. In contrast, increased [cAMP]i levels led to sustained inducible cAMP early repressor (ICER) II/IIγ mRNA and protein induction. To understand these data in relation to the in vivo setting, HCC tumors were analyzed and compared to pair‐matched normal liver (NL) samples. These studies demonstrated significantly elevated Gsα‐protein expression in HCC versus NL in the absence of significant changes in basal cAMP levels. Analysis of total and active CREB demonstrated significantly increased total CREB/pCREB in HCC versus NL. Further analysis of CRE expression demonstrated significantly increased expression of ICER mRNA and protein in HCC versus sham operated (Sh). These data demonstrate cAMP, while capable of stimulating promitogenic CREB activation inhibits cell mitogenesis in HCC possibly via ICER induction. J. Cell. Physiol. 206: 411–419, 2006.

Hypophosphatemia after 95 right-lobe living-donor hepatectomies for liver transplantation is not a significant source of morbidity

Background. Hypophosphatemia appears to be a universal event after right hepatic lobectomy for live-donor adult liver transplantation according to one report. Because hypophosphatemia appears to contribute to increased postoperative complications, routine hyperalimentation with supratherapeutic levels of phosphorus was advocated. Methods. From July 2000 to May 2002, we performed 95 right-lobe living-donor hepatectomies for 95 adult liver-transplant recipients, the largest single institutional experience. We reviewed our data that were collected prospectively. Results. We did not find profound hypophosphatemia (<1.0 mg/dL) to be prevalent in our donors. At least six (6.3%) donors did not have postoperative hypophosphatemia. In addition, there appears to be no increased morbidity related to hypophosphatemia when aggressively corrected with intravenous or oral phosphates in our group of donors that underwent right-lobe hepatectomies. Conclusions. We, therefore, cannot endorse the routine administration of hyperalimentation with supratherapeutic phosphorus because of its potential morbidity.

The quick, No-Twist, No-Kink portal confluence reconstruction

An aggressive surgical approach remains the best palliation and chance for 5-year survival in the treatment of locally advanced pancreatic cancer. Increasingly, this approach has involved partial or total resection of the portal vein (PV) or superior mesenteric vein (SMV) in combination with pancreaticoduodenectomy. Many studies have suggested that such resections done successfully are associated with an increased survival relative to nonresected patients, comparable with that of patients undergoing uncomplicated pancreaticoduodenectomy alone. Successful performance of portal resection remains extremely challenging because of the risk of uncontrolled bleeding and the difficulty encountered in preventing twisting or kinking of the reconstructed vessel. Prolonged partial or complete portal and mesenteric venous occlusion generally result in the development of bowel edema that makes the subsequent reconstruction more difficult. Recently, we and others have examined results of an aggressive surgical approach in the treatment of locally advanced pancreatic carcinoma. In our series, 43% of patients underwent partial portal vein resection with minimal additional blood loss, operative time, and postoperative complications, including pancreatic fistulae (unpublished observation). Our technique of portal vein resection, which preserves the anatomic relationship of the vessels in that region, allowing an easier reconstruction without kink or rotation of the portal-mesenteric confluence, is presented.

Inhibition of alcohol dehydrogenase blocks enhanced Gi-protein expression following ethanol treatment in experimental hepatocellular carcinoma in vitro.

Objective Chronic alcohol abuse is one of the major contributors to the onset and progression of hepatocellular carcinoma (HCC). We have previously identified increased expression and function of inhibitory guanine nucleotide regulatory proteins (Gi-proteins) in primary human and animal models of HCC. Stimulation of Gi-proteins in HCC stimulates cell mitogenesis, an effect not observed in hepatocytes. The aim of this study was to determine the effect of ethanol and ethanol metabolism on Gi-protein expression in an experimental model of HCC. Design Pharmacological agents that inhibit alcohol metabolism were used in conjunction with ethanol or ethanol metabolites. We were also able to assess the relative contribution of alcohol and acetaldehyde, the major metabolite of alcohol, on Gi-protein expression in HCC and hepatocytes. Methods These studies used the rat hepatic tumorigenic H4IIE cell line in conjunction with isolated rat hepatocytes. Cells were cultured in vitro and exposed to ethanol, ethanol in the presence of an alcohol dehydrogenase (ADH) inhibitor, or acetaldehyde for varying lengths of time. Ethanol metabolism and changes in Gi-protein expression were subsequently determined by assay. Results Exposure to ethanol alone led to significant dose and time dependent increases in Giα1/2 and Giα3 protein and mRNA expression in HCC cells. In contrast, ethanol failed to alter Giα1/2, and only moderately affected Giα3 protein expression in isolated cultured hepatocytes. Pretreatment of HCC cells and hepatocytes with 4-methyl pyrazole (4-MP, 10 μm) significantly inhibited alcohol metabolism. Treatment of HCC cells with 4-MP inhibited changes in Gi-protein expression following exposure to ethanol (25 mm, 24 h). In addition, the increased expression of Gi-proteins observed after exposure to ethanol in HCC were mimicked by direct exposure of HCC cells to acetaldehyde in a dose and time dependent manner. Conclusions These data suggest that alcohol metabolites, not alcohol, lead to increased Gi-protein expression in HCC in vitro. Ethanol and ethanol metabolites, in contrast, fail to significantly alter Giα1/2 protein expression in hepatocytes. These data may have significant implications in HCC progression in vivo.

Inflammatory myofibroblastic tumors

INTRODUCTIONnInflammatory myofibroblastic tumors (IMT) while uncommon may arise within numerous organs. Historically, the literature regarding IMT has been confined to small one organ case series, with few reviews encompassing multiple anatomic sites, and little data regarding adjuvant treatment.nnnMETHODSnA review of patients with IMT treated at two large academic medical centers over a 15-year period was undertaken. Patient demographics, pathologic diagnoses, and pertinent clinical data were obtained.nnnRESULTSnForty-four cases of pathologically confirmed IMT were identified. Tumor locations included multiple anatomic sites. Therapies included complete resection, incomplete resection, observation, or chemotherapy, and/or radiation. Five patients underwent adjuvant chemotherapy and/or radiation therapy following surgery (14%) for local aggressiveness of the tumor, invasion, positive margins, or location of tumor that was not amenable to surgical resection. A second, concomitant, histologically distinct, neoplasm was identified in five cases. Of the patients who underwent treatment three local recurrences were noted (8%) and occurred in patients with partial resection without adjuvant chemo- or radiotherapy.nnnCONCLUSIONSnInflammatory myofibroblastic tumors may be a locally aggressive and destructive neoplasm. Tumor recurrence is unusual following complete surgical resection or organ-preserving combined modality therapy.