Masataka Seike

Adiponectin protects LPS‐induced liver injury through modulation of TNF‐α in KK‐Ay obese mice

Adiponectin, an adipocytokine, has been identified in adipose tissue, and its receptors are widely distributed in many tissues, including the liver. The present study was performed to clarify the role of adiponectin in lipopolysaccharide (LPS)‐induced liver injury using KK‐Ay obese mice. We analyzed the effects of adiponectin pretreatment on liver injury induced by D‐galactosamine/LPS (GalN/LPS) in KK‐Ay obese mice. GalN/LPS treatment induced significant increases in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in the blood, apoptotic and necrotic changes in hepatocytes, and/or showed a high degree of lethality. The GalN/LPS‐induced liver injury was more pronounced in KK‐Ay obese mice than in lean controls. Pretreatment with adiponectin ameliorated the GalN/LPS‐induced elevation of serum AST and ALT levels and the apoptotic and necrotic changes in hepatocytes, resulting in a reduction in lethality. In addition, pretreatment with adiponectin attenuated the GalN/LPS‐induced increases in serum and hepatic tumor necrosis factor α (TNF‐α) levels and increased peroxisome proliferator‐activated receptor (PPAR) α messenger RNA expression in the liver. Furthermore, abdominal macrophages from KK‐Ay obese mice pretreated with adiponectin in vitro exhibited decreased LPS‐induced TNF‐α production compared with controls. Finally, adiponectin pretreatment also ameliorated TNF‐α‐induced liver injury. In conclusion, these findings suggest that adiponectin prevents LPS‐induced hepatic injury by inhibiting the synthesis and/or release of TNF‐α of KK‐Ay obese mice. (HEPATOLOGY 2004;40:177–184.)

TNF-α induces hepatic steatosis in mice by enhancing gene expression of sterol regulatory element binding protein-1c (SREBP-1C)

We investigated the effect of tumor necrosis factor-α (TNF-α), a member of the proinflammatory cytokine family, on steatosis of the mouse liver by analyzing morphological changes and hepatic triglyceride content in response to TNF-α. We also examined expression of the sterol regulatory element binding protein-1c gene. Intraperitoneal injection of TNF-α acutely and dramatically accelerated the accumulation of fat in the liver, as evidenced by histological analysis and hepatic triglyceride content. This treatment increased liver weight, increased serum levels of free fatty acids, and increased fatty acid synthase and sterol regulatory element binding protein-1c mRNA expression. Furthermore, intraperitoneal injection of lipopolysaccaride (LPS) to induce TNF-α expression also accelerated hepatic fat accumulation. Pretreatment with anti-TNF-α antibody attenuated the development of LPS-induced fatty change in the liver. Antibody pretreatment not only decreased sterol regulatory element binding protein-1c expression in LPS-treated mice but also attenuated the expression of suppressors of cytokine signaling-3 mRNA. This study suggests that TNF-α, acting downstream of LPS, increases intrahepatic fat deposition by affecting hepatic lipogenetic metabolism involving sterol regulatory element binding protein-1c.

Guidelines for the treatment of chronic hepatitis and cirrhosis due to hepatitis B virus infection for the fiscal year 2008 in Japan

In the 2008 guidelines for the treatment of patients with cirrhosis, who are infected with hepatitis B virus (HBV), the main goal is to normalize levels of alanine and aspartate aminotransferases by eliminating HBV or reducing viral loads. In patients with compensated cirrhosis, the clearance of HBV from serum is aimed for by entecavir, as the main resort, for histological improvement toward the prevention of hepatocellular carcinoma (HCC). In patients with decompensated cirrhosis, by contrast, meticulous therapeutic strategies are adopted for the reversal to compensation, toward the eventual goal of decreasing the risk of HCC. For maintaining liver function and preventing HCC, branched chain amino acids and nutrient supplements are applied, in addition to conventional liver supportive therapies. For patients with chronic hepatitis B, separate guidelines are applied to those younger than 35 years and those aged 35 years or older. Even for patients with chronic hepatitis who are negative for hepatitis e antigen (HBeAg), but who harbor HBV DNA in titers of 7 log copies/mL or more, a “drug‐free state” is aimed for by sequential treatment with interferon (IFN) plus entecavir as the first line. For patients with chronic hepatitis B aged 35 years or older, who are HBeAg‐negative and carry HBV DNA in titers of less than 7 log copies/mL, long‐term IFN for 24–48 weeks is adopted anew. To HBeAg‐negative patients who have either or both platelet counts of less than 150 × 103/mm3 and less than 7 log copies of HBV DNA, also, long‐term IFN for 24–48 weeks is indicated.

Role of fatty acid composition in the development of metabolic disorders in sucrose-induced obese rats.

Fatty acids have been shown to be involved in the development of insulin resistance associated with obesity. We used sucrose loading in rats to analyze changes in fatty acid composition in the progression of obesity and the related metabolic disorder. Although rats fed a sucrose diet for 4 weeks had body weights similar to those of control animals, their visceral fat pads were significantly larger, and serum triglyceride levels were higher; however, neither plasma glucose nor insulin levels were significantly higher. After 20 weeks of sucrose loading, body weight and visceral and subcutaneous fat pads had increased significantly compared with those in control rats. Moreover, plasma glucose, Insulin, and triglyceride levels were significantly higher. An analysis of individual fatty acid components in the blood and peripheral tissues demonstrated phase- and tissue-dependent changes. After 20 weeks of sucrose loading, palmitoleic acid (16:1 n-7) and oleic acid (18:1 n-9), the major components of monounsaturated fatty acid, showed a ubiquitous increase in plasma and all tissues analyzed. In contrast, linoleic acid (18:2 n-6) and arachidonic acid (20:4 n-6), the major components of polyunsaturated fatty acid in the n-6 family, decreased in plasma and all tissues analyzed. After 4 weeks of sucrose loading, these changes in fatty acid composition were observed only in the liver and plasma and not in fat and muscle. This led us to conclude that elevation of plasma glucose and insulin develop at the late phase of sucrose-induced obesity, when changes in fatty acid composition appear in fat and muscle. Furthermore, changes in fatty acid composition in liver seen after 4 weeks of sucrose loading, when increases in neither plasma glucose nor insulin were detected, suggest that liver may be the initial site of fatty acid imbalance and that aberrations in hepatic fatty acid composition may lead to fatty acid imbalances in other tissues.

Effect of vitamin K2 on the recurrence of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is characterized by frequent recurrence, even after curative treatment. Vitamin K2, which has been reported to reduce HCC development, may be effective in preventing HCC recurrence. Patients who underwent curative ablation or resection of HCC were randomly assigned to receive placebo, 45 mg/day, or 90 mg/day vitamin K2 in double‐blind fashion. HCC recurrence was surveyed every 12 weeks with dynamic computed tomography/magnetic resonance imaging, with HCC‐specific tumor markers monitored every 4 weeks. The primary aim was to confirm the superiority of active drug to placebo concerning disease‐free survival (DFS), and the secondary aim was to evaluate dose‐response relationship. Disease occurrence and death from any cause were treated as events. Hazard ratios (HRs) for disease occurrence and death were calculated using a Cox proportional hazards model. Enrollment was commenced in March 2004. DFS was assessed in 548 patients, including 181 in the placebo group, 182 in the 45‐mg/day group, and 185 in the 90‐mg/day group. Disease occurrence or death was diagnosed in 58, 52, and 76 patients in the respective groups. The second interim analysis indicated that vitamin K2 did not prevent disease occurrence or death, with an HR of 1.150 (95% confidence interval: 0.843‐1.570, one‐sided; P = 0.811) between the placebo and combined active‐drug groups, and the study was discontinued in March 2007.

Isoleucine Prevents the Accumulation of Tissue Triglycerides and Upregulates the Expression of PPARα and Uncoupling Protein in Diet-Induced Obese Mice

In this study, we investigated the effects of the branched-chain amino acid l-isoleucine (Ile) on both obesity and glucose/fat homeostasis in mice that were fed a high-fat (45% energy) diet. The mice were divided into different treatment groups and given a high-fat diet for 6 wk. During the last 4 wk, Ile was dissolved and added to the drinking water to a final concentration of 2.5%. The control mice received vehicle alone. The mice in the Ile group had an almost 6% lower body weight gain and 49% less epididymal white adipose tissue (WAT) mass with the control group (P < 0.05). The hepatic and skeletal muscle triglyceride (TG) concentrations and degree of hyperinsulinemia in the Ile group mice were also lower than the control group by 38, 47, and 39%, respectively (P < 0.05). The WAT leptin concentration was also lower, whereas that of adiponectin was higher, in the Ile group compared with the control group (P < 0.05). The hepatic levels of protein CD36/fatty acid translocase, PPARalpha, and uncoupling protein (UCP) 2 and the levels of UCP3 in skeletal muscle were all greater in the Ile group than in the control mice (P < 0.05). These results demonstrate that the liver and muscle TG concentrations are both lowered by Ile treatment. In addition, the PPARalpha and UCP expression levels in the mouse tissues were greater in the Ile group compared with the controls. Our current data thus suggest that supplementation with Ile might be useful in the treatment of metabolic syndrome.

A Novel Anti-Inflammatory Role for Spleen-Derived Interleukin-10 in Obesity-Induced Inflammation in White Adipose Tissue and Liver

Obesity is associated with systemic low-grade inflammation and obesity-related metabolic disorders. Considering that obesity decreases the expression of proinflammatory cytokines in the spleen, we assessed the role of interleukin (IL)-10, an anti-inflammatory cytokine produced by the spleen, in the pathogenesis of obesity. Changes in obesity-related pathogenesis, including inflammatory responses in multiple organs, were assessed after systemic administration of exogenous IL-10 to splenectomy (SPX)-treated obese wild-type and IL-10 knockout (IL-10KO) mice. Obesity resulted in the inability of the spleen to synthesize cytokines, including IL-10, and proinflammatory cytokines in obesity are then likely to emerge from tissues other than the spleen because serum levels of IL-10, but not proinflammatory cytokines, decreased despite the expression of these cytokines in the spleen being reduced in high fat–induced obese mice. SPX aggravated the inflammatory response in white adipose tissue (WAT) and the liver and suppressed adiposity in WAT. However, it accentuated adiposity in the liver. These SPX-induced changes were inhibited by systemic administration of IL-10. Moreover, SPX had little effect on the inflammatory responses in WAT and the liver of IL-10KO mice. These data show the role of spleen-derived IL-10 in diet-induced changes as a result of inflammatory responses in WAT and the liver.

Evidence-based clinical practice guidelines for nonalcoholic fatty liver disease/nonalcoholic steatohepatitis*

Nonalcoholic fatty liver disease (NAFLD) is currently the most common cause of chronic liver disease in industrialized countries worldwide, and has become a serious public health issue not only in Western countries but also in many Asian countries including Japan. Within the wide spectrum of NAFLD, non‐alcoholic steatohepatitis (NASH) is a progressive form of disease, which often develops into liver cirrhosis and increases the risk of hepatocellular carcinoma. In turn, a large proportion of NAFLD/NASH is the liver manifestation of metabolic syndrome, suggesting that NAFLD/NASH plays a key role in the pathogenesis of systemic atherosclerotic diseases. Currently, a definite diagnosis of NASH requires liver biopsy, though various non‐invasive measures are under development. The mainstays of prevention and treatment of NAFLD/NASH include dietary restriction and exercise; however, pharmacological approaches are often necessary. Currently, vitamin E and thiazolidinedione derivatives are the most evidence‐based therapeutic options, although the clinical evidence for long‐term efficacy and safety is limited. This practice guideline for NAFLD/NASH, established by the Japanese Society of Gastroenterology in cooperation with The Japan Society of Hepatology, covers lines of clinical evidence reported internationally in the period starting from 1983 through January 2012, and each clinical question was evaluated using the GRADE system. Based on the primary release of the full version in Japanese, this English summary provides the core essentials of this clinical practice guideline comprising the definition, diagnosis, and current therapeutic recommendations for NAFLD/NASH in Japan.

The role of histamine H1 receptor and H2 receptor in LPS-induced liver injury

To examine the role of histamine H1 and H2 receptors in the regulation of lipopolysaccharide (LPS)‐induced liver injury, a combination of D‐galactosamine and LPS (GalN/LPS) was administered to histamine H1 receptor knockout (H1‐R KO) and H2 receptor knockout (H2‐R KO) mice. The numbers of necrotic and apoptotic hepatocytes in the liver, as well as the levels of serum aspartate transaminase (AST) and alanine transaminase (ALT), were increased significantly by GalN/LPS treatment compared to the appropriate controls. Pretreatment with histamine ameliorated the GalN/LPS‐induced necrotic and apoptotic changes in the hepatocytes and inhibited the elevation of serum AST and ALT levels. Histamine attenuated the GalN/LPS‐induced increases in the levels of TNF‐α, but augmented those of IL‐10 both in the liver and serum. Histamine inhibited the GalN/LPS‐induced caspase‐3 activity in the liver. Furthermore, these effects of histamine were completely or partially attenuated in H2‐R KO mice, but not in H1‐R KO mice. Peritoneal macrophages from H2‐R KO mice exhibited blunted changes in the effects of histamine on LPS‐induced TNF‐α and IL‐10 production in vitro compared to the wild‐type (WT) controls. In summary, the present findings suggest that the histamine H2‐R‐TNF‐α and ‐IL‐10 pathways play protective roles in endotoxin‐induced hepatic injury. Masaki, T., Chiba, S., Tatsukawa, H., Noguchi, H., Kakuma, T., Endo, M., Seike, M., Watanabe, T., Yoshimatsu, H. The role of histamine H1 receptor and H2 receptor in LPS‐induced liver injury. FASEB J. 19, 1245–1252 (2005)

Novel mutations of the ATP7B gene in Japanese patients with Wilson disease

AbstractWilson disease (WD) is an autosomal recessive disorder characterized by copper accumulation in the liver, brain, kidneys, and corneas, and culminating in copper toxication in these organs. In this study, we analyzed mutations of the responsible gene, ATP7B, in four Japanese patients with WD. By direct sequencing, we identified five mutations, of which two were novel, and 16 polymorphisms, of which 6 were novel. The mutations 2871delC and 2513delA shift the reading frame so that truncated abnormal protein is expected. In contrast to these mutations found in patients with hepatic-type of early onset, the mutations A874V, R778L, and 3892delGTC were either missense mutations or inframe 1-amino acid deletion, and occurred in the patients with hepato-neurologic type of late onset. The mutations 2871delC and R778L have been previously reported in a relatively large number of Japanese patients. In particular, R778L is known to be more prevalent in Asian countries than in other countries of the world. Our data are compatible with the hypothesis that the mutations tend to occur in a population-specific manner. Therefore, the accumulation of the types of mutations in Japanese patients with WD will facilitate the fast and effective genetic diagnosis of WD in Japanese patients.