[Diagnosis of and therapy for nonalcoholic steatohepatitis].
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Antioxidants↗
Biomedical subjects
Toshiji Saibara
Publications and source records attributed to Toshiji Saibara.
[Non-alcoholic steatohepatitis (NASH). 2. Insulin resistance and NASH].
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Fatty Liver↗
Universal vaccination and thereafter.
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Disease Outbreaks↗
Clinical features of nonalcoholic steatohepatitis in Japan: Evidence from the literature.
Metabolic syndrome, that is, obesity, hypertension, hyperlipidemia, and insulin resistance with hyperinsulinemia, is a new disease entity prevailing worldwide, and nonalcoholic steatohepatitis (NASH) is believed to be a hepatic expression of this syndrome. NASH is characterized by zone 3-dominant hepatic steatosis with ballooned hepatocytes and Mallory bodies, zone 3 pericellular and perivenular fibrosis with or without bridging fibrosis, and lobular inflammatory cell infiltration. Indeed, 90% of NASH has been revealed to be complicated by visceral obesity, and two-thirds of NASH patients fulfill the criteria of metabolic syndrome. Therefore, a variety of lifestyle-related diseases such as obesity, hypertension, hyperlipidemia, and diabetes mellitus may share the same background. NASH is most prevalent and well characterized in Caucasians; however, little is known about its occurrence in Asia-Oceania, because obesity has not been frequent in countries in these areas. Obesity is expected to become a serious social problem in Asia-Oceania in the next two decades, so we need to prevent a corresponding increase of NASH. For that purpose, we need to know much about not only NASH but also ourselves. To elucidate the status of NASH in Japan, recent progress in the study of NASH in Japan is reviewed in this article.
Blood Glucose↗
Vascularization in tissue remodeling after rat hepatic necrosis induced by dimethylnitrosamine.
We observed postnecrotic tissue remodeling to examine vascularization in adult rat livers. Livers, bone marrow, and peripheral blood from rats at 24 h to 14 days after an injection of dimethylnitrosamine (DMN) were examined by light microscopic, immunohistochemical, and ultrastructural methods. Numerous ED-1 (a marker for rat monocytes/macrophages)-positive round mononuclear cells infiltrated in the necrotic areas at 36 h after DMN treatment. On day 5, when necrotic tissues were removed, some of the cells were transformed from round to spindle in shape. On day 7, these cells were contacted with residual reticulin fibers and became positive for SE-1, a marker of hepatic sinusoidal endothelial cells and Tie-1, an endothelial cell-specific surface receptor, associated with frequent occurrence of ED-1/SE-1 and ED-1/Tie-1 double-positive spindle cells. Ultrastructurally, the spindle cells simultaneously showed phagocytosis and endothelial cell-like morphology. With time necrotic areas diminished, and on day 14, the necrotic tissues were almost replaced by regenerated liver tissues and thin bundles of central-to-central bridging fibrosis. Bone marrow from 12 h to day 2 showed an increase of BrdU-positive mononuclear cells. Some of them were positive for ED-1. The BrdU-labeled and ED-1-positive cells appeared as early as 12 h after DMN injection and reached a peak in number at 36 h. They were similar in structure to ED-1-positive cells in necrotic liver tissues. These findings suggest that round mononuclear ED-1-positive cells proliferate first in bone marrow after DMN treatment, reach necrotic areas of the liver through the circulation, and differentiate to sinusoidal endothelial cells. Namely, hepatic sinusoids in DMN-induced necrotic areas may partly be reorganized possibly by vasculogenesis.
Animals↗
In vivo imaging of hepatic fatty acid metabolism in patients with non-alcoholic steatohepatitis using semiquantitative 123I-labeled branched-chain fatty acid analog.
Obesity is now prevailing worldwide, coincident with the increase of hepatic steatosis. Metabolic syndrome with obesity and hypertension, hyperlipidemia, and impaired glucose tolerance is one of the most frequent life-threatening diseases and non-alcoholic steatohepatitis is believed to be a hepatic expression of this syndrome. Non-alcoholic steatohepatitis is prevalent and well characterized in Caucasians, but little is known about non-alcoholic steatohepatitis in Asia-Oceania. Obesity will be a serious social problem in Asia-Oceania in the next two decades and we need to prevent the increase of this syndrome. Therefore, it is extremely important to know about non-alcoholic steatohepatitis based on racial differences, because this syndrome is likely to be a multi-factorial syndrome resulting from different combinations of susceptibility genes superimposed on different environmental factors. Because hepatic steatosis is the first step in the development of not only metabolic syndrome but also non-alcoholic steatohepatitis, the genetic background of Japanese NASH patients was investigated and a measure to assess fatty acid beta-oxidation in the liver in vivo was developed.
Animals↗
[Drug-induced NASH].
Steatohepatitis is pathologically characterized by zone 3-dominant hepatic steatosis with ballooned hepatocytes and Mallory bodies, zone 3 pericellular and perivenular fibrosis with or without bridging fibrosis, and lobular inflammatory cell infiltration. Alcoholic hepatitis is a prototype of this syndrome, but a variety of diseases such as obesity, diabetes mellitus, Wilson disease and hepatitis C could reveal very similar pathological changes in some occasions. Therefore, well defined diseases need to be excluded in the process of differential diagnosis of steatohepatitis. Pathways possibly involved in the development of drug-induced steatohepatitis were categorized into four and outlines of the possible mechanisms involved in the development of this syndrome were proposed in this article.
Amiodarone↗
[NASH and metabolic syndrome].
Visceral obesity and insulin resistance are typical clinical features of nonalcoholic steatohepatitis (NASH) characterized by zone 3-dominant hepatic steatosis with ballooned hepatocytes and Mallory bodies, zone 3 pericellular and perivenular fibrosis with or without bridging fibrosis, and lobular inflammatory cell infiltration. Indeed, 90% of NASH revealed to be complicated with visceral obesity, and two thirds of NASH patients fulfill the criteria of metabolic syndrome. Therefore, NASH could be regarded as the hepatic manifestation of metabolic syndrome, and a variety of life-style related diseases such as obesity, hypertension, hyperlipidemia and diabetes mellitus could be used for detecting
Fatty Liver↗
Assessment of anti-estrogenic activity of tamoxifen in transgenic mice expressing an enhanced green fluorescent protein gene regulated by estrogen response element.
Tamoxifen is an anti-estrogenic agent for the treatment of breast cancer, while exhibiting estrogenic activity in such tissues as the uterus. This study aimed to test whether these opposite properties of tamoxifen in the uterus can be evaluated separately in vivo. We employed two transgenic murine models named, respectively, the ERE-EGFP Ar+/+ mouse and ERE-EGFP Ar-/- mouse. Both types of mice possess an enhanced green fluorescent protein (EGFP) gene regulated by four copies of estrogen response elements (EREs), while the latter lacks a functional aromatase gene, which encodes an enzyme catalyzing conversion of androgens to estrogens. Tamoxifen clearly exhibited estrogenic activity in the uteri of ERE-EGFP Ar-/- mice, as it caused uterine wet weight gain and E2-target gene induction, as 17beta-estradiol (E2) did. However, tamoxifen did not enhance the EGFP expression in ERE-EGFP Ar-/- mice, although E2 induced it significantly. In ERE-EGFP Ar+/+ mice, tamoxifen suppressed the EGFP expression in a time- and dose-dependent manner. Thus, the present study demonstrated that estrogenic and anti-estrogenic activities of tamoxifen can be evaluated by using ERE-EGFP Ar-/- and ERE-EGFP Ar+/+ mice, respectively. Furthermore, these animal models are useful to select and evaluate estrogenic and anti-estrogenic activities of chemical compounds.
Animals↗
Nonalcoholic steatohepatitis in Asia-Oceania.
Metabolic syndrome, i.e., obesity, hypertension, hyperlipidemia and insulin resistance with hyperinsulinemia is a new disease entity prevailing worldwide and nonalcoholic steatohepatitis is believed to be a hepatic expression of this syndrome. Nonalcoholic steatohepatitis is prevalent and well characterized in Caucasians, however, little is known about nonalcoholic steatohepatitis in Asia-Oceania, because obesity has not been frequent in these countries. Obesity is sure to be a serious social problem in Asia-Oceania in the next two decades and we need to prevent the increase of nonalcoholic steatohepatitis. For that purpose, we need to know much about not only nonalcoholic steatohepatitis but also ourselves, as this syndrome is believed to be based not only on genetic but also environmental background.
Journal Article↗
Effects of obstructive sleep apnea syndrome on hepatic steatosis and nonalcoholic steatohepatitis.
Hepatic steatosis occasionally progresses to nonalcoholic steatohepatitis. This study was designed to examine whether non-obese patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) were prone to develop hepatic steatosis and whether repeated hypoxemia contributed to the progression of steatohepatitis. This study included 83 OSAHS patients and 41 age-, body mass index (BMI)- and gender-matched non-OSAHS patients diagnosed by polysomnography. Hepatic steatosis was defined by a liver/spleen ratio <0.9 on abdominal computerized tomography, and latent steatohepatitis was evaluated based on serum levels of type III procollagen (P-III-P). Visceral fat (V-fat) accumulated much more in OSAHS patients. Liver/spleen ratios in OSAHS patients correlated negatively with BMI and, especially, with the amount of visceral fat. Serum levels of P-III-P in OSAHS patients correlated negatively with the average of oxygen saturation during sleep, and positively with BMI, the apnea-hypopnea index (AHI) and the amount of V-fat. Multiple regression analysis showed that average SaO(2) was the only explanatory variable for P-III-P values, but AHI, BMI and V-fat was not. These observations confirmed that non-obese patients with OSAHS are at a risk for visceral obesity, and suggested that oxygen desaturation during sleep is a risk for developing latent steatohepatitis, especially in patients with substantial hepatic steatosis.
Journal Article↗
Similar anti-mitochondrial antibody reactivity profiles in familial primary biliary cirrhosis.
AIMS: : Familial accumulation of primary biliary cirrhosis (PBC) has been documented. To examine the importance of genetic factors, we carried out family study of the disease with a particular focus on the reactivity profiles of anti-mitochondrial antibodies (AMA). PATIENTS AND METHODS: : Eighty-five patients with PBC that we experienced in the period of 1982-2003 were investigated, retrospectively. Twelve patients from a total of six families were investigated clinically and immunologically. RESULTS: : Of the 85 patients, 5 (5.9%) were found to have a family history of PBC. The six PBC family relationships consisted of four cases of sisters and two cases of a mother and daughter. HLA haplotypes were identical in two cases and were half-similar in the other cases. AMA titers were almost the same in three families and in five of the six families, sera from individual members within the family showed similar AMA-reactive bands in immunoblotting. CONCLUSION: : The prevalence of PBC is strikingly increased in family members (frequency of 5.9%). Sera from PBC patients of the same family showed the same AMA reactivity profile, suggesting that development of AMA may be greatly influenced by certain underlying genetic factors. Large-scale genomic studies of familial PBC will be critical to identify mechanisms of disease susceptibility.
Journal Article↗
Expression of the estrogen-inducible EGFP gene in aromatase-null mice reveals differential tissue responses to estrogenic compounds.
Aromatase is an enzyme responsible for the conversion of androgen to estrogen. We genetically engineered an aromatase-deficient mouse (Ar(-/-) mouse) to express an enhanced green fluorescent protein (EGFP) gene in the uterus, ovary, adrenal and pituitary glands in a 17beta-estradiol (E2)-inducible manner. In this study, we analyzed estrogenic activities of diethylstilbestrol, genistein, daidzein and E2 in the Ar(-/-) tissues by using the EGFP expression as an indicator. These analyses manifest differential responses of the tissues to the compounds and also allow to determine the relative estrogenic potency of the compounds to that of E2 in vivo. Furthermore, analyses of the EGFP expression in ERalpha-deficient mice suggested that the expression is ERalpha-dependent in the uterus and pituitary gland. In conclusion, the Ar(-/-) mouse carrying the E2-inducible EGFP gene is a valuable tool for quantitative analyses of natural and synthetic estrogenic compounds in vivo.
Adrenal Glands↗
In vivo imaging of hepatic fatty acid metabolism in patients with nonalcoholic steatohepatitis using semiquantative (123)I-BMIPP liver scan.
Recent progress of studies in NASH displays multi-disciplinary characters of the pathogeneses. Despite these advances, the strategic use of imaging modalities such as CT, US, and MRI, remains a relatively low priority in clinical situations, because these can only visualize the presence of fatty infiltration to the hepatic parenchyma, impossible to figure out the dynamic function of NASH liver. Morphological alteration such as CT value, MR signal intensity and echo-grade do not distinguish NASH from simple fatty liver. In this presentation, from a radiologic viewpoint, we show the feasibility of in vivo fatty acid imaging with (123)I-beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP). BMIPP is an (123)I labeled fatty acid analog for imaging damaged myocardium, using conventional nuclear imaging equipment. Under normal conditions, the energy source for myocardial utilization is dependent on the beta-oxidation of fatty acids. For energy production in ischemic myocardium, the drastic switch from reduced beta-oxidation of fatty acids to glucose metabolism is well known. BMIPP can detect the area of reduced fatty acids metabolism on myocardial imaging and the data can be converted into semiquantitative analysis. Therefore, we speculate that the use of BMIPP to in vivo hepatic imaging in NASH could highlight a lot of matters of NASH. Details of this presentation include: (1) Hepatic imaging with BMIPP; (2) Clearance of BMIPP from NASH liver; (3) semiquantitative analysis of hepatic BMIPP clearance and clinical features of NASH; (4) Profiles of NASH categorized by BMIPP imaging and (5) Preliminary data of BMIPP clearance in patients with Tamoxifen-induced NASH. The core of our stance in this presentation is searching for valuable advice on clinical use of BMIPP in patients with NASH from specialists in the field of HEPATOLOGY.
Journal Article↗
CYP17 polymorphism and tamoxifen-induced hepatic steatosis.
Hepatic steatosis is a frequent complication, which sometimes develops nonalcoholic steatohepatitis (NASH), in breast cancer patients treated with tamoxifen, a potent antagonist of estrogen. Recently we reported the impairment of fatty acid beta-oxidation and the enhancing fatty infiltration to hepatocytes in aromatase deficiency (ArKO) mice as the estrogen deficiency models. This experimental observation let us speculate strong link between estrogen and hepatic steatosis. In this study, we investigated whether a polymorphism in the cytochrome P450c17alpha gene (CYP17), which is associated with circulating estrogen levels, influences the development of tamoxifen-induced hepatic steatosis. This consecutive study included 180 breast cancer patients undergoing tamoxifen treatment. Genomic DNA extracted from the peripheral blood of each patient was analyzed by restriction fragment length polymorphism (defined as the A1 and A2 alleles). The extent of hepatic steatosis was assessed by computed tomography (CT) as the liver/spleen (L/S) ratio. While receiving adjuvant tamoxifen, 57 of 180 patients developed hepatic steatosis (L/S ratio <0.9) without obvious changes in body mass index (BMI). We observed a significant association between the A2/A2 genotype and the development of hepatic steatosis compared with the A1/A1 genotype [odds ratio (OR), 3.60; 95% confidence interval (C.I.)=1.42-9.10]. The A1/A2 genotype was at an intermediately increased risk of hepatic steatosis (OR, 2.24; 95% C.I.=0.99-5.08). The presence of the A2 allele possibly increased the progression of hepatic steatosis with a gene dosage effect (P=0.06). Our results suggest that functional polymorphism in CYP17 may be involved in determining susceptibility of tamoxifen-induced hepatic steatosis.
Journal Article↗
CYP17 polymorphism as a risk factor of tamoxifen-induced hepatic steatosis in breast cancer patients.
Oral administration of tamoxifen, an endocrine therapy for breast cancer, often induces hepatic steatosis (THS, tamoxifen-induced hepatic steatosis) as a complication, which can progress to non-alcoholic steatohepatitis (NASH). The development of this complication is strongly associated with three clinical risk factors; specifically, insulin resistance, central obesity, and hypertriglyceridemia, however a genetic predisposition to THS has yet to be investigated. The aim of this study is to determine whether genetic polymorphism of the P450c17alpha enzyme coded for by the CYP17 gene, responsible for regulating serum estrogen, has an association with THS. After obtaining informed consent from 180 eligible breast cancer patients treated with tamoxifen, DNA was collected and analyzed by restriction fragment length polymorphism assay and classified into alleles defined as A1 and A2. The absence or presence and extent of THS was evaluated by calculating the liver/spleen (L/S) ratio based on Hounsfield units with a CT scanner. Administration of tamoxifen led to THS (L/S ratio <0.9) in 57 (31.7%) of 180 patients while the remaining 123 (68.3%) patients did not develop THS. A significant difference in the distribution of CYP17 genotypes was observed between patients who developed THS and those who did not (P=0.021). A significantly higher frequency of the A2 allele was seen in the THS group (odds ratio, 1.90; 95% confidence interval, 1.21-2.99). Our study provides the first evidence that CYP17 polymorphism participates in the development of THS, and sheds light on the genetic causes of this side effect and genetic differences between tamoxifen-treated individuals.
Adult↗
Polymorphisms of microsomal triglyceride transfer protein gene and manganese superoxide dismutase gene in non-alcoholic steatohepatitis.
BACKGROUND/AIMS: The pathogenesis of non-alcoholic steatohepatitis (NASH) is poorly understood. The aim of this study was to examine genetic influences on NASH pathogenesis. METHODS: Blood samples from 63 patients with biopsy-proven NASH and 150 healthy controls were analyzed by the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Two functional polymorphisms were studied: the -493 G/T polymorphism in the promoter of microsomal triglyceride transfer protein (MTP) and the 1183 T/C polymorphism in the mitochondrial targeting sequence of manganese superoxide dismutase (MnSOD). RESULTS: NASH patients had a much higher incidence of the MTP gene G allele (P=0.001) and of the G/G genotype (P=0.002) compared to the controls. Fat occupied more area in liver lobules and the stage of NASH was advanced in patients with the G/G-genotype than in patients with G/T-genotype (P=0.04). NASH patients also had a higher incidence of the MnSOD T/T genotype (P=0.016). CONCLUSIONS: The G allele in the MTP promoter leads to decreased MTP transcription, less export of triglyceride from hepatocytes, and greater intracellular triglyceride accumulation. The T allele in MnSOD mitochondrial targeting sequence leads to less transport of MnSOD to the mitochondria. Therefore, functional polymorphisms in MTP and MnSOD may be involved in determining susceptibility of NASH.
Adult↗