Toshihiro Nishio

Nuclear factor κB inactivation in the rat liver ameliorates short term total warm ischaemia/reperfusion injury

Background: In hepatic ischaemia/reperfusion injury, activated liver macrophages (Kupffer cells) are dominantly regulated by a transcription factor, nuclear factor κB (NFκB), with respect to expression of inflammatory cytokines, acute phase response proteins, and cell adhesion molecules. Aims: We assessed whether inactivation of NFκB in the liver could attenuate total hepatic warm ischaemia/reperfusion injury. Methods: We studied rats with hepatic overexpression of inhibitor κBα super-repressor (IκBα SR) caused by a transgene introduced using an adenoviral vector. Hepatic ischaemia/reperfusion injury was induced under warm conditions by total occlusion of hepatoduodenal ligament structures for 20 minutes, followed by reperfusion. Controls included uninfected and control virus (AdLacZ) infected rats. Results: IκBα SR was overexpressed in Kupffer cells as well as in hepatocytes, blocking nuclear translocation of NFκB (p65) into the nucleus after reperfusion. Gene transfection with IκBα SR, but not with LacZ, markedly attenuated ischaemia/reperfusion injury, suppressing inducible nitric oxide synthase and nitrotyrosine expression in the liver. Moreover, no remarkable hepatocyte apoptosis was detected under IκBα SR overexpression. Conclusions: Adenoviral transfer of the IκBα SR gene in the liver ameliorates short term warm ischaemia/reperfusion injury, possibly through attenuation of hepatic macrophage activation.

Inactivation of the small GTPase Rac1 protects the liver from ischemia/reperfusion injury in the rat.

BACKGROUND In ischemia/reperfusion (I/R) injury, a massive generation of reactive oxygen species (ROS) after reperfusion is a critical factor. Rac, a member of the Rho GTPase superfamily, plays important roles in the production of ROS and activation of nuclear factor-kappaB (NF-kappaB) in vitro. However, the exact role of Rac in the ROS production and NF-kappaB activation in vivo after I/R is still obscure. METHODS We blocked Rac1 activity in the rat liver using adenovirus encoding a dominant negative rac1 mutant (Ad5N17Rac1) and examined whether inactivation of Rac1 could prevent ROS generation in the hepatic I/R injury. Seventy-two hours after the adenoviral infection, hepatic I/R was induced by Pringles maneuver for 20 minutes, followed by reperfusion in the rats. RESULTS Ad5N17Rac1 infection significantly attenuated ROS production after reperfusion and suppressed the hepatic injury. Furthermore, N17Rac1 suppressed NF-kappaB activation and messenger RNA expression of tumor necrosis factor-alpha (TNF-alpha) and inducible nitric oxide synthetase (iNOS). Ad5LacZ, a control adenovirus, had no effect on the induced hepatic I/R injury, nor did it affect NF-kappaB activation. Immunohistochemical analysis of NF-kappaB (p65) revealed that translocation of p65 to the nucleus after reperfusion was blocked in many of non-parenchymal cells (NPCs) and in hepatocytes in the Ad5N17Rac1-infected liver. CONCLUSION We conclude that Rac1 is required in ROS generation and NF-kappaB activation after hepatic I/R in vivo, and that inactivation of NF-kappaB in NPCs and suppression of ROS generation in NPCs and hepatocytes possibly account for the protective effect of N17Rac1 in this study.

Continuous intravenous infusion of deleted form of hepatocyte growth factor attenuates hepatic ischemia–reperfusion injury in rats

BACKGROUND/AIMS Although beneficial roles of hepatocyte growth factor (HGF) and its variants on several hepatic disorders have been reported, their effects on hepatic ischemia-reperfusion (IR) injury remain undetermined. We investigated the action of a deleted form of HGF (dHGF) on hepatic IR injury in rats. METHODS dHGF or phosphate-buffered saline was continuously infused intravenously for 20 h prior to a 20-min occlusion of hepatic vessels. Samples were taken before and after IR, for measurement of serum dHGF and released enzymes, liver gamma-glutamylcysteinyl glycine (GSH) level, as well as histological and immunohistochemical examinations. RESULTS After reperfusion, histological injury, as well as increase in the serum activities of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and creatine kinase-BB were significantly attenuated in the dHGF-treated rats. dHGF maintained a high GSH level and suppressed oxidative stress and intercellular adhesion molecule-1 (ICAM-1) expression on sinusoidal endothelial cells (SECs), on which c-Met was not detected. IR caused activation of c-Met expression, which was milder in the dHGF-treated group, in hepatocytes at the pericentral region. CONCLUSIONS dHGF attenuated liver injury after IR. It also maintained a higher GSH level, depressed oxidative stress and inhibited ICAM-1 expression on c-Met negative SECs, suggesting a paracrine effect of dHGF.

Increased expression of collagenase in the liver induces hepatocyte proliferation with cytoplasmic accumulation of β-catenin in the rat

BACKGROUND/AIMS Since the hepatic extracellular matrix is remodeled in liver regeneration, we investigated whether increased collagenase activity in the liver can induce hepatocyte proliferation in vivo. METHODS To increase hepatic collagenase activity, human matrix metalloproteinase-1 was delivered to the rat liver by the recombinant adenoviral vector Ad5MMP-1. RESULTS Hepatic delivery of Ad5MMP-1 increased the 5-bromo-2-deoxyuridine labeling index and mitotic index in hepatocytes, causing an increase in the dry liver weight; control adenovirus, Ad5LacZ, had minimal effect. Hepatocyte proliferation started approximately 48 h after infection with Ad5MMP-1 and ended after about 2 weeks. The increase in the dry liver weight also returned to baseline after 2 weeks. Transient liver injury by Ad5MMP-1, reflected by increased aspartate and alanine aminotransferase levels, peaked around 1 week, and was associated with hepatocyte apoptosis. Collagenase-induced hepatocyte proliferation was accompanied by cytoplasmic accumulation of beta-catenin and a transient decrease in E-cadherin expression. CONCLUSIONS Modification of the hepatic extracellular matrix by collagenase induces transient hepatocyte proliferation in vivo, suggesting that the condition of the hepatic extracellular matrix per se plays a pivotal role in regulating hepatocyte proliferation.

Right hepatic lobectomy for hepatocellular carcinoma which developed in primary biliary cirrhosis: Report of a case

The case of a 74-year-old female patient who underwent a right hepatic lobectomy for hepatocellular carcinoma (HCC) which developed in primary biliary cirrhosis (PBC) is reported herein. During a follow-up examination for Parkinson’s disease, an elevation of hepatobiliary tractrelated enzymes and α-fetoprotein was uncovered. Diagnostic imagings showed a hypervascular, solitary, and encapsulated tumor measuring about 7 cm in diameter located mainly in the posterior segment. Positive antimitochondrial and antinuclear antibodies and a preoperative liver biopsy strongly suggested well differentiated HCC developed in PBC (Scheuer’s classification stage II). Since the natural prognosis of PBC estimated by the Mayo risk score was fairly good and the liver function indicated sufficient tolerance for major hepatic resection, and preoperative computed tomography (CT) volumetry showed the atrophy of the right hepatic lobe, a right hepatic lobectomy was performed. A pathological examination revealed well encapsulated, moderately differentiated HCC with, in part, well-differentiated HCC in the tumor and stage II PBC in the noncancerous region. CT volumetry performed at postoperative day 14 showed a 146% enlargement of the remnant liver. An early detection of HCC and PBC by strict screening would prevent a limitation of surgical therapy due to a deteriorated liver function.

Technetium-99m-sestamibi scintimammography of benign and malignant phyllodes tumors

We presented two cases of phyllodes tumor of the breast examined by99mTc-sestamibi (MIBI) two-phase scintimammography. In the case with malignant phyllodes tumor,99mTc-MIBI accumulation was recognized on both early and delayed images. In the case with benign phyllodes tumor, however,99mTc-MIBI accumulation was recognized on only the early image.99mTc-MIBI delayed imaging may have the potential to distinguish between benign and malignant phyllodes tumors.

Giant malignant phyllodes tumor with99mTc-Ses-tamibi accumulation: Report of a case

We report a case of a giant malignant phyllodes tumor examined by99mTc-ses-tamibi (MIBI) mammoscintigraphy. The patient was a 51 year-old woman who complained of bleeding from a large mass in her right breast. The tumor was well circumscribed, with an ulcerized surface. The accumulation of99mTc-MIBI in the tumor was recognized on99mTc-MIBI scintigraphy. A standard radical mastectomy was performed with a wide margin of skin. The resected specimen measured 20 X 17 X 13 cm, weighed 2100 g and was histologically diagnosed as a malignant phyllodes tumor. The skin defect was reconstructed by a rectus abdominis musculocutaneous flap, with good cosmetic results.99mTc-MIBI scintigraphy may have the potential to distinguish a malignant from benign phyllodes tumors.

Optical analysis of the cirrhotic liver by near-infrared time-resolved spectroscopy.

Purpose.To assess the histological severity of liver cirrhosis in relation to the optical properties of liver tissue.Methods.Various grades of liver cirrhosis were induced in rats by giving intraperitoneal injections of thioacetamide (TAA) over periods ranging from 4 to 16 weeks. The optical properties of the liver, absorption coefficient (µa) and scattering coefficient (µs′), were measured by near-infrared time-resolved spectroscopy.Results.Histological examination confirmed cirrhotic changes in the liver, which were more severe in the rats given TAA for longer periods. The µa increased in the 4- and 8-week rats, then decreased in the 12- and 16-week rats. The µa of the blood-free liver decreased as liver cirrhosis progressed. The hemoglobin concentration in the liver, calculated from the µa values, increased in the 4- and 8-week rats and decreased in the 12- and 16-week rats. The µs′ decreased in the cirrhotic liver, probably reflecting the loss of volume of hepatocytes. The product of µa and µs′ proved useful to evaluate the severity of cirrhosis.Conclusions.These results showed that the optical properties correlated well with the severity of liver cirrhosis, indicating that the clinical application of this method is encouraging.