Yukishige Okamura

Superoxide anion release into the hepatic sinusoid after an acute ethanol challenge and its attenuation by Kupffer cell depletion.

Superoxide anion release into the hepatic sinusoids and subsequent damage to the endothelial cells of the hepatic sinusoids after ethanol challenge was examined. A 250 mg/kg body weight/hr dose of ethanol was given to rats for 3 hr, and superoxide anion release into the hepatic sinusoids was examined in a liver perfusion model using the cytochrome c method. Ethanol treatment resulted in superoxide anion release into the hepatic sinusoids (0.20 ± 0.01 vs. 0.12 ± 0.02 o.d., p< 0.05) and an increase in the purine nucleoside phosphorylase/alanine aminotransferase ratio in the liver perfusate, a marker of damage to the endothelial cells of the hepatic sinusoids (0.003 ± 0.002 vs. 0.008 ± 0.002; p < 0.05). Tumor necrosis factor-alpha was not detectable in either group, and there were no significant differences in the population of hepatic macrophages, leukocytes, or Kupffer cells between the two groups. To clarify the role of Kupffer cells in the mechanism, 10 mg/kg of body weight of gadolinium chloride was given to rats twice, 24 hr apart, resulting in depletion of ED2-positive cells from the hepatic lobules. The superoxide anion release after the ethanol challenge was significantly attenuated in the Kupffer cell-depleted rats, compared with the controls (0.14 ±0.02;p <0.05, compared with ethanol alone). The change was associated with a significant decrease in the purine nucleoside phosphorylase/alanine aminotransferase ratio in the liver perfusate (0.004 ± 0.002; p < 0.05, compared with ethanol alone). Ethanol causes superoxide anion release into the hepatic sinusoid and subsequent damage to the sinusoidal endothelial cells. These changes were reduced by Kupffer cell depletion. This supports the view that Kupffer cell depletion has a protective effect on ethanol-induced liver injury.

Kupffer cell depletion attenuates superoxide anion release into the hepatic sinusoids after lipopolysaccharide treatment

Background and Aim:  The mechanisms involved in the beneficial effect of gadolinium chloride against endotoxin‐induced liver damage were studied.

Splenectomy attenuates superoxide anion release into the hepatic sinusoids after lipopolysaccharide challenge

BACKGROUND/AIMS The aim of this study was to determine whether the spleen contributes to superoxide anion release into the hepatic sinusoids and subsequent damage to endothelial cells of the hepatic sinusoids after lipopolysaccharide challenge. METHODS Rats were given 2 mg/kg body weight lipopolysaccharide. Three hours after the treatment, superoxide anion release into the hepatic sinusoids was examined in a liver perfusion model using the cytochrome C method. Damage to endothelial cells of the hepatic sinusoids was assessed from the purine nucleoside phosphorylase/glutamic-pyruvic transaminase ratio in the liver perfusate. To further characterize the mechanisms behind these changes, these studies were done in rats given superoxide dismutase or an anti-TNFalpha antibody. To study whether the spleen plays a role in the mechanisms, experiments with splenectomized rats were performed. RESULTS Lipopolysaccharide challenge resulted in superoxide anion release into the hepatic sinusoids and damage to endothelial cells of the hepatic sinusoids. These changes were significantly attenuated by the treatments with superoxide dismutase or an antibody against TNFalpha, as well as by splenectomy. The hepatic macrophage and Kupffer cell populations after lipopolysaccharide challenge were significantly smaller in the rats given splenectomy than in those given a sham operation. There were no significant differences in the neutrophil populations between the two groups. Levels of TNFalpha were significantly lower in the former than the latter, whereas there were no significant differences in levels of Interleukin-8 between the two groups. CONCLUSIONS Splenectomy reduced the superoxide anion release into the hepatic sinusoids caused by the lipopolysaccharide challenge and subsequent damage to endothelial cells of the hepatic sinusoids. This supports the view that splenectomy has a protective effect in lipopolysaccharide-induced liver injury.

Effect of chronic ethanol feeding on endotoxin-induced hepatic injury: role of adhesion molecules on leukocytes and hepatic sinusoid

Endotoxin is postulated to be an important aggravating factor for alcoholic liver disease. We have previously reported that rats fed ethanol are more vulnerable to endotoxin-induced liver damage, and hepatic microcirculatory disturbance plays an important role for this liver damage by observation with an intravital microscopy. In this study, we have investigated the role of adhesion molecules in endotoxin-induced microcirculatory disturbance in chronic ethanol-fed rats. Male Wistar rats were pair-fed with ethanol liquid diet (ethanol group) or an isocaloric control diet (control group) for 6 weeks. Leukocyte adherence to the hepatic sinusoid by stimulation with lipopolysaccharides (1 mg/kg of body weight) was observed by an inverted fluorescence microscopy equipped with a silicon-intensified target camera and was found to be enhanced in ethanol-fed rats. Tumor necrosis factor-alpha and GRO/CINC-1 (rat counterpart of interleukin-8) was increased in the blood in these animals. Subsequent expression of adhesion molecules, LFA-1 beta-chain on leukocytes were demonstrated by flow cytometry, which suggests a possible involvement of leukocyte adherence to the hepatic damage in ethanol-fed animals. Preadministration of anti-rat LFA-1 beta-chain monoclonal antibody effectively suppressed leukocyte adherence to the hepatic sinusoid. These results suggest that the enhanced sequestration of neutrophils to the liver with these adhesion molecules may play a significant role in the pathogenesis of alcoholic liver disease.

Evidence for Ethanol Oxidation by Kupffer Cells

Ethanol oxidation in Kupffer cells was investigated by measuring 14 C-acetate formation from 14 C-ethanol, and the role of aldehyde dehydrogenase 2 (ALDH2) in this process was also examined. Formation of 14 C-acetate from 20 mM of 14 C-ethanol was significantly increased in medium-containing Kupffer cells (9,003 + 2,066 cpm/5 × 106 cells), compared with medium containing no cells (1,826 + 46 cpm,p < 0.01), or containing acid-killed Kupffer cells (1,629 + 210 cpm,p < 0.01). Ethanol formation was significantly attenuated when 20 and 200 μM cyanamide or 2 μM disulfiram were given. Reverse transcriptase-polymerase chain reaction demonstrated that Kupffer cells carry mRNA for ALDH2. These findings indicate that Kupffer cells can oxidize ethanol to acetate. ALDH2 may participate in this process, especially in the conversion of acetaldehyde to acetate.

Formation of superoxide anion in the hepatic sinusoid after lipopolysaccharide challenge

Using the cytochrome c method, superoxide anion that is released into the hepatic sinusoid was measured after a lipopolysaccharide challenge in a liver perfusion system. Moreover, damages of epithelial cells of the hepatic sinusoid were estimated with scanning electron microscopic analysis and levels of purine nucleoside phosphorylase/GPT ratio. Lipopolysaccharide administration increased the conversion of oxidized cytochrome c into reduced cytochrome c in the perfusate, indicating that superoxide anion was formed in the hepatic sinusoid. This change was associated with increase in levels of portal tumor necrosis factor-alpha and attenuated by the simultaneous administration of superoxide dismutase. Scanning electron microscope analysis revealed that diameters of sinusoidal fenestrae increased in rats treated with lipopolysaccharide, compared with controls. Moreover, levels of purine nucleoside phosphorylase/GPT ratio was significantly increased in the liver perfusate in lipopolysaccharide-treated rats, compared with controls. Superoxide anion in hepatic sinusoid may be one of the pathogenic factors behind damages of epithelial cells of the hepatic sinusoid caused by lipopolysaccharide.

Education and imaging. Gastrointestinal: capsule endoscopy assists in the complete deworming of parasites.

A 67-year-old man presented with the complaint of ribbon-like substances in the feces. In the beginning of August 2010, he was referred to our hospital for treatment of parasitic worm infection. The patient did not have symptoms such as diarrhea, anemia, or weight loss; the results of physical and hematological examinations and of thoracoabdominal radiography were normal. Although he did not have a history of parasitic worm infection and had never traveled abroad, he had eaten raw salmon 1 month ago. On the first day of the hospital visit, the patient was diagnosed with diphyllobothriasis after examination of the helminth eggs found in the feces. After diatrizoic acid swallow on the second day, the presence of the worm body was confirmed by colonoscopy, and the worm body was extirpated from the anus by using grasping forceps. Although approximately 1 m of the worm body together with most of the neck portion was successfully extirpated, removal of the scolex was not confirmed. On the fourth day, after obtaining the patient’s consent, we performed capsule endoscopy because of possible incomplete deworming. Capsule endoscopy confirmed parasitization by a cestode and detected the scolex attached to the jejunal mucosa (Figure 1). Parasite-specific drugs, i.e., praziquantel and magnesium citrate, were administered, and complete deworming was subsequently confirmed by microscopic identification of the scolex (Figure 2). The worm body was pathologically confirmed as Diphyllobothrium nihonkaiense by performing trichrome and carmine staining (Figure 3). For the successful treatment of diphyllobothriasis, it is essential to remove the scolex of the parasite. The use of capsule endoscopy now allows for (1) easy capture of images of parasites, such as that of the scolex of Diphyllobothrium nihonkaiense, in the small intestine, which was previously considered difficult; and (2) provides information critical for therapeutic decision making before administering anthelmintics.

Gastrointestinal: Capsule endoscopy assists in the complete deworming of parasites

A 67-year-old man presented with the complaint of ribbon-like substances in the feces. In the beginning of August 2010, he was referred to our hospital for treatment of parasitic worm infection. The patient did not have symptoms such as diarrhea, anemia, or weight loss; the results of physical and hematological examinations and of thoracoabdominal radiography were normal. Although he did not have a history of parasitic worm infection and had never traveled abroad, he had eaten raw salmon 1 month ago. On the first day of the hospital visit, the patient was diagnosed with diphyllobothriasis after examination of the helminth eggs found in the feces. After diatrizoic acid swallow on the second day, the presence of the worm body was confirmed by colonoscopy, and the worm body was extirpated from the anus by using grasping forceps. Although approximately 1 m of the worm body together with most of the neck portion was successfully extirpated, removal of the scolex was not confirmed. On the fourth day, after obtaining the patient’s consent, we performed capsule endoscopy because of possible incomplete deworming. Capsule endoscopy confirmed parasitization by a cestode and detected the scolex attached to the jejunal mucosa (Figure 1). Parasite-specific drugs, i.e., praziquantel and magnesium citrate, were administered, and complete deworming was subsequently confirmed by microscopic identification of the scolex (Figure 2). The worm body was pathologically confirmed as Diphyllobothrium nihonkaiense by performing trichrome and carmine staining (Figure 3). For the successful treatment of diphyllobothriasis, it is essential to remove the scolex of the parasite. The use of capsule endoscopy now allows for (1) easy capture of images of parasites, such as that of the scolex of Diphyllobothrium nihonkaiense, in the small intestine, which was previously considered difficult; and (2) provides information critical for therapeutic decision making before administering anthelmintics.

Induction of NADPH Cytochrome P-450 Reductase in Kupffer Cells After Chronic Ethanol Consumption Associated with Increase of Superoxide Anion Formation

Using native polyacrylamide gel electrophoresis (PAGE) and diaphorase staining, NADPH cytochrome c P-450 reductase was examined in the Kupffer cells of rats fed ethanol chronically as well as in controls. Formation of superoxide anion released from Kupffer cells into the hepatic sinusoid was estimated using the cytochrome c method, which was applied to a liver perfusion model in both groups after an additional acute ethanol challenge. Kupffer cells were found to carry NADPH cytochrome c P-450 reductase, and chronic ethanol consumption resulted in its induction being doubled. This change was associated with increase of superoxide anion release from Kupffer cells into the hepatic sinusoid after an acute ethanol challenge (0.020 ± 0.03 O.D./g liver versus 0.012 ± 0.002 O.D./g liver; P < .05). In conclusion, release of superoxide anion from Kupffer cells into the hepatic sinusoid increases in rats chronically fed ethanol. Induction of NADPH reductase in Kupffer cells caused by chronic ethanol consumption may, at least in part, be involved in this mechanism.

Gastrointestinal: Capsule endoscopy assists in the complete deworming of parasites: Education and Imaging

A 67-year-old man presented with the complaint of ribbon-like substances in the feces. In the beginning of August 2010, he was referred to our hospital for treatment of parasitic worm infection. The patient did not have symptoms such as diarrhea, anemia, or weight loss; the results of physical and hematological examinations and of thoracoabdominal radiography were normal. Although he did not have a history of parasitic worm infection and had never traveled abroad, he had eaten raw salmon 1 month ago. On the first day of the hospital visit, the patient was diagnosed with diphyllobothriasis after examination of the helminth eggs found in the feces. After diatrizoic acid swallow on the second day, the presence of the worm body was confirmed by colonoscopy, and the worm body was extirpated from the anus by using grasping forceps. Although approximately 1 m of the worm body together with most of the neck portion was successfully extirpated, removal of the scolex was not confirmed. On the fourth day, after obtaining the patient’s consent, we performed capsule endoscopy because of possible incomplete deworming. Capsule endoscopy confirmed parasitization by a cestode and detected the scolex attached to the jejunal mucosa (Figure 1). Parasite-specific drugs, i.e., praziquantel and magnesium citrate, were administered, and complete deworming was subsequently confirmed by microscopic identification of the scolex (Figure 2). The worm body was pathologically confirmed as Diphyllobothrium nihonkaiense by performing trichrome and carmine staining (Figure 3). For the successful treatment of diphyllobothriasis, it is essential to remove the scolex of the parasite. The use of capsule endoscopy now allows for (1) easy capture of images of parasites, such as that of the scolex of Diphyllobothrium nihonkaiense, in the small intestine, which was previously considered difficult; and (2) provides information critical for therapeutic decision making before administering anthelmintics.