Heigo Takeuchi

A new free radical scavenger, edaravone, ameliorates oxidative liver damage due to ischemia-reperfusion in vitro and in vivo

Ischemia-reperfusion injury causes oxidative stress producing reactive oxygen species, which is a serious problem linked to morbidity and mortality in liver surgery. We investigated the effects of edaravone, a new free radical scavenger, on liver oxidative stress in vitro and in vivo. We employed a hypoxiareoxygenation model of primary cultured hepatocytes using an AnaeroPack (Mitsubishi Gas Chemical Co., Tokyo, Japan). Hepatocytes were exposed to 3 or 4 hours of hypoxia and then returned to oxygenation. We analyzed the time course changes of aspartate aminotransferase (AST), phosphatidylcholine hydroperoxide (PCOOH), and adenosine triphosphate (ATP) content in hepatocytes of edaravone-treated groups or nontreated groups after reoxygenation. Edaravone significantly attenuated the elevation of the AST level of the medium and hepatocellular PCOOH and preserved the hepatocellular ATP level. In vivo, male Sprague-Dawley rats were subjected to 45 minutes of hepatic ischemia and 120 minutes of reperfusion. The rats were intravenously injected with vehicle or edaravone (3 mg/kg or 10 mg/kg) before reperfusion and 1 hour after reperfusion. Serum AST levels and hepatic PCOOH and energy charge were significantly improved in both edaravone groups compared with control. In conclusion, edaravone has the ability to eliminate intra-hepatocellular superoxide species and attenuate oxidative liver damage in liver surgery.

The involvement of the intracellular superoxide production system in hepatic ischemia-reperfusion injury. In vivo and in vitro experiments using transgenic mice manifesting excessive CuZn-SOD activity.

In vivo and in vitro studies were conducted using transgenic mice with 1.8-fold increased SOD activity in the cytoplasmic fraction compared to normal mice in order to evaluate the role of cytoplasmic superoxide dismutase (SOD) in hepatic ischemia-reperfusion injury. In the in vivo study, after inducing 15 min 70% partial hepatic ischemia followed by 45 min reperfusion, we determined the plasma levels of ALT, hyaluronic acid, and phosphatidylcholine hydroperoxide (PCOOH) as the membranous lipoperoxide of the hepatic tissue. In addition, in vitro ischemia-reperfusion studies for cultured hepatocytes were conducted in an anaerobic chamber that could create a hypoxic or oxygen-rich environment in order to clarify the amelioration of reperfusion injuries in the SOD rich hepatocytes. High levels of ALT and PCOOH were found as a result of reperfusion in normal mice, while a suppression of the increase in these levels was noted in the transgenic mice. In both groups, the hyaluronic acid levels were not modified. These results suggest that intracellular superoxide production is involved in the mechanism of hepatic ischemia-reperfusion injury, and that an improvement of the ability to eliminate intracellular superoxide species can contribute to the prevention of reperfusion injury.

Granulocyte-colony stimulating factor-producing pancreatic cancer: Report of a case

A 74-year-old man was hospitalized for the investigation of fever and severe general fatigue. Laboratory examinations revealed severe leukocytosis, with a leukocyte count of 29 500/mm3. Computed tomography, ultrasonography, and endoscopic retrograde cholangiopancreatography showed a pancreatic tumor with a diameter of 70mm. We performed distal pancreatectomy with splenectomy and gastrectomy because there was invasion of the posterior wall of the stomach. The leukocyte count decreased to 16 900/mm3 immediately following the operation, but it began to increase again a week later, ultimately reaching 213 000/mm3. We measured the serum granulocyte-colony stimulating factor (G-CSF) concentration and the G-CSF expressions in the resected specimens with immunohistochemistry, the findings of which confirmed the diagnosis of G-CSF-producing pancreatic cancer. G-CSF-producing tumors are considered to be in a category of rare malignant diseases originating in various organs, which carry a poor prognosis. However, G-CSF-producing pancreatic cancer is extremely rare. On postoperative day (POD) 35, an intraabdominal recurrence was detected with marked leukocytosis, and on POD 42 the patient died without receiving postoperative cancer therapy.

Splenic vein occlusion secondary to tuberculous lymphadenitis at the splenic hilum: report of a case.

Abstract: We report a patient with splenic vein occlusion (SVO) secondary to tuberculosis. A 17-year-old male patient with mild epigastric pain and splenomegaly was found to have gastric varices by gastroscopy, and SVO by selective angio-graphy. At operation, the splenic vein was occluded by hard fibrous tissue at the splenic hilum, and thus a splenectomy was performed. A microscopic examination of the tissue revealed caseous necrosis surrounded by epithelioid cells and Langhans-type giant cells. Although there were no other findings suggesting intestinal tuberculosis, it seemed that tuberculous lymphadenitis of the splenic hilum most likely caused the occlusion of the splenic vein. Because specific tests for tuberculosis were negative in both immunohistochemical staining for bacille Calmette-Guérin and polymerase chain reaction of DNA for Mycobacterium tuberculosis , the time of infection was assumed to have occurred a long time before. SVO can sometimes be seen in pancreatic diseases, but this patient with tuberculosis appears to be the first such reported case in the English literature.

Hepatic phosphatidylcholine hydroperoxide content in noncirrhotic, cirrhotic, and antioxidant-treated rats with endotoxemia

Hepatic phosphatidylcholine hydroperoxide (PCOOH) was studied intensively to delineate its role in the altered pathophysiology of liver failure associated with endotoxemic shock. Endotoxemia was induced by cecal ligation and puncture (CLP) in three models using rats. Model 1 consisted of normal healthy rats; model 2, cirrhotic rats; and model 3, rats treated with catalase and superoxide dismutase (SOD). Samples were taken before CLP, then 12h and 24 h following CLP. A progressive and significant increase in serum endotoxin was seen in all models; however, a significantly low energy charge (EC) and high PCOOH were seen in models 1 and 2, whereas no change was observed in model 3. The regional blood flow remained unchanged throughout the experiment in models 1 and 3, but not in model 2. An initial increase in α-tocopherol was seen in model 1. The survival rate was markedly better in model 3 than in models 1 or 2. The fall in EC corresponded to the increase in serum endotoxin as well as to the increase in tissue PCOOH in models 1 and 2. It was more likely that the elevated lipid peroxidation in model 1 resulted from endotoxemia rather than from tissue hypoperfusion. The early increase in α-tocopherol that occurred in models 1 and 2, but not in model 3, indicated the antiradical defense response to oxidative injury. Thus, antioxidant therapy significantly improved the survival rate and tissue adenine nucleotide level in spite of the increased serum endotoxin level.