Cordyceps militaris alleviates non-alcoholic fatty liver disease in ob/ob mice

BACKGROUND/OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) is becoming an important public health problem as metabolic syndrome and type 2 diabetes have become epidemic. In this study we investigated the protective effect of Cordyceps militaris (C. militaris) against NAFLD in an obese mouse model.

MATERIALS/METHODS

Four-week-old male ob/ob mice were fed an AIN-93G diet or a diet containing 1% C. militaris water extract for 10 weeks after 1 week of adaptation. Serum glucose, insulin, free fatty acid (FFA), alanine transaminase (ALT), and proinflammatory cytokines were measured. Hepatic levels of lipids, glutathione (GSH), and lipid peroxide were determined.

RESULTS

Consumption of C. militaris significantly decreased serum glucose, as well as homeostasis model assessment for insulin resistance (HOMA-IR), in ob/ob mice. In addition to lowering serum FFA levels, C. militaris also significantly decreased hepatic total lipids and triglyceride contents. Serum ALT activities and tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels were reduced by C. militaris. Consumption of C. militaris increased hepatic GSH and reduced lipid peroxide levels.

CONCLUSIONS

These results indicate that C. militaris can exert protective effects against development of NAFLD, partly by reducing inflammatory cytokines and improving hepatic antioxidant status in ob/ob mice.     

Oral citrulline supplementation protects female mice from the development of non-alcoholic fatty liver disease (NAFLD)

Purpose

Impairments of intestinal barrier function are discussed as risk factors for the development and progression of non-alcoholic fatty liver disease (NAFLD). Studies suggest an association between arginine/citrulline homeostasis and the development of liver damages. Here, the effect of an oral l-citrulline (Cit) supplement on the development of a Western-style diet (WSD)-induced NAFLD was determined in mice.

Methods

Female 6- to 8-week-old C57BL/6J mice were either pair-fed a liquid Western-style or control diet (C) ± 2.5 g/kg bodyweight Cit for 6 weeks (C + Cit or WSD + Cit). Indices of liver damage, glucose metabolism, intestinal barrier function and NO synthesis were measured.

Results

While bodyweight gain was similar between groups, markers of glucose metabolism like fasting blood glucose and HOMA index and markers of liver damage like hepatic triglyceride levels, number of neutrophils and plasminogen activator inhibitor-1 protein levels were significantly lower in WSD + Cit-fed mice when compared to WSD-fed mice only. Protein levels of the tight junction proteins occludin and zonula occludens-1 in duodenum were significantly lower in mice fed a WSD when compared to those fed a WSD + Cit (?~70 and ?~60 %, respectively, P < 0.05), whereas portal endotoxin levels, concentration of 3-nitrotyrosine protein adducts in duodenum and toll-like receptor-4 mRNA expression in livers of WSD + Cit-fed mice were markedly lower than in WSD-fed mice (?~43 %, P = 0.056; ?~80 and ?~48 %, respectively, P < 0.05).

Conclusion

Our data suggest that the protective effects of supplementing Cit on the development of NAFLD in mice are associated with a decreased translocation of endotoxin into the portal vein.

     

The role of hepatic fat accumulation in pathogenesis of non-alcoholic fatty liver disease (NAFLD)

Nonalcoholic fatty liver disease is increasingly regarded as a hepatic manifestation of metabolic syndrome, and the severity of nonalcoholic fatty liver disease seems to increase in parallel with other features of metabolic syndrome. Excess lipid accumulation in the liver cells is not only a mediator of Metabolic Syndrome and indicator of a lipid overload but also accompanied by a range of histological alterations varying from 'simple' steatosis to nonalcoholic steatohepatitis, with time progressing to manifest cirrhosis. Hepatocellular carcinoma may also occur in nonalcoholic steatohepatitis -related cirrhosis with a mortality rate similar to or worse than for cirrhosis associated with hepatitis C. This review summarizes the knowledge about the causal relationship between hepatic fat accumulation, insulin resistance, liver damage and the etiological role of hepatic fat accumulation in pathogenesis of extra- and intra-hepatic manifestations. Special emphasis is given suggestions of new targets treatment and prevention of nonalcoholic fatty liver disease.     

MicroRNA在非酒精性脂肪性肝病发病过程中作用的研究进展

微小RNA（microRNA, miRNA）是一种小的非编码RNA,参与机体的生理和病理反应。非酒精性脂肪性肝病（non-alcoholic fatty liver disease, NAFLD）是以弥漫性肝细胞大泡性脂肪变性为主要特征的临床病理综合征。近年来,有报道称miRNA在肝脏炎症、纤维化和硬化中发挥了一定的作用,尤其是在NAFLD发生发展过程中,miRNA表达特点、致病机制、临床诊治中的意义等方面引起了较大关注,故本文对此进行综述。     

三氯生改善非酒精性脂肪性肝病小鼠的肝脏脂肪沉积

目的 探究三氯生对小鼠非酒精性脂肪性肝病（nonalcoholic fatty liver disease,NAFLD）的改善作用。方法 使用高脂饲料连续喂养雄性C57BL/6J小鼠12周建立NAFLD小鼠模型,随机分为模型对照组、低、中、高剂量三氯生［100、200、400 mg/（kg·d）］实验组,每组10只,每天灌胃一次,连续给药8周。每周记录小鼠体重,收集小鼠血清与肝脏组织,使用试剂盒检测血清中甘油三酯（TG）、总胆固醇（TC）以评价小鼠血脂水平,检测血清中谷丙转氨酶（ALT）、谷草转氨酶（AST）含量评价小鼠肝功状况,使用苏木精-伊红( HE) 染色观察小鼠肝组织病理变化,油红O染色观察小鼠肝脏脂肪沉积情况并对脂滴面积比进行定量计算。结果 与空白对照组相比,模型对照组小鼠体重（F = 8.384, P＜0.001）、血清TG（F = 7.113,P＜0.001）、TC（F = 4.234, P = 0.006）、ALT（F = 9.632,P＜0.001）、AST（F = 6.719,P = 0.001）均上升,肝脏组织HE染色可见大量气球样变与脂滴空泡,油红O染色可见大量、大面积的橘红色脂滴。与模型对照组比,低、中、高剂量三氯生组小鼠体重分别下降17%、19%和30%（F = 26.884,P＜0.001）,血清TG（F = 9.993, P＜0.001）、TC（F = 1.078, P = 0.373）、ALT（F = 4.236, P = 0.020）、AST（F = 3.954,P = 0.028）水平出现不同程度的下降; HE染色显示低、中、高剂量三氯生组小鼠肝脏细胞气球样变与脂滴空泡减少,肝脏组织形态得到改善;油红O染色可见低、中、高剂量三氯生组小鼠肝脏组织橘红色脂滴的面积随三氯生剂量的增加而减小。对脂肪沉积情况进行定量计算,结果显示各剂量三氯生组小鼠肝脏的脂滴面积比与模型对照相比分别降低了27%、42%与50%（F = 96.950, P＜0.001）。结论 三氯生可以减少NAFLD小鼠肝脏脂肪含量,恢复肝脏功能并降低血脂,改善由高脂饮食诱导的NAFLD。     

清华大学教工非酒精性脂肪肝及相关因素分析

  目的  探讨铁超载对高脂膳食诱导非酒精性脂肪肝病（NAFLD）大鼠二价金属离子转运蛋白（DMT1）、膜铁转运蛋白（FPN1）基因表达影响。  方法  采用高脂高铁饮食诱导非酒精性脂肪肝病大鼠模型,测定大鼠血清甘油三酯、总胆固醇、葡萄糖、胰岛素水平,计算胰岛素抵抗指数（HOMA-IR）;苏木素–伊红染色观察大鼠肝脏病理组织改变;逆转录–聚合酶链反应（RT-PCR）法检测大鼠十二指肠 DMT1和FPN1 mRNA表达水平。  结果  高脂高铁组大鼠血清TG含量[（0.61 ± 0.07）μmol/L],明显高于对照组（P < 0.05）,血清胰岛素和HOMA-IR分别为 [（27.73 ± 8.29）mIU/L和（6.06 ± 1.88）],明显高于对照组和高脂组（P < 0.05）;高脂高铁组大鼠肝脏脂肪变性程度较高脂组严重;高脂高铁组大鼠十二指肠DMT1和FPN1 mRNA相对表达量分别为[（0.81 ± 0.03）和（0.69 ± 0.11）],均低于对照组（P < 0.05）。  结论  高脂高铁联合作用可诱发大鼠胰岛素抵抗,加重肝脏脂肪变性程度,并使大鼠肠道铁吸收负反馈调节作用降低。     

Iron metabolism in genetically obese (ob/ob) mice

Several reports in the clinical literature suggest that obese children may be at risk for developing iron deficiency. Here the absorption, retention, tissue distribution and tissue levels of iron were compared in lean (+/?) and obese (ob/ob) C57BL/6J mice to examine the impact of obesity on the iron status of this animal model. Obese mice absorbed and retained approximately twice as much 59Fe as lean mice after receiving a solution containing 1 mumol iron per os. This difference was independent of age, severity of obesity and mass of the gastrointestinal tract. Obese mice fed ad libitum had higher levels of 59Fe in blood and fat pads, but lower amounts of 59Fe in the skeletal-muscular system, than lean mice 6 d after subcutaneous injection of 1 mumol of the metal. At least 30% of carcass 59Fe was present in the liver of obese and lean mice 6 d after injection. Despite significantly lower concentrations of iron in liver and bone, blood hemoglobin and hematocrit were significantly higher in obese mice fed ad libitum than in lean mice at 10 wk of age. Plasma iron and transferrin were not affected by chronic obesity. Although several characteristics of iron metabolism differed in obese and lean mice, the results indicate that ob/ob mice were not iron deficient when fed a diet containing an adequate level of this micronutrient. The increased absorption of iron by obese mice probably represents an adaptive response that is required to supply additional micronutrient for the expanded blood volume in these animals.     

Zinc metabolism in genetically obese (ob/ob) mice

Recent reports indicate that the concentrations and total amounts of several essential trace metals in various tissues of genetically obese rodents differ markedly from those in lean controls. In the present studies the absorption, retention and tissue distribution of zinc and constitutive levels of zinc-metallothionein (Zn-MT) in selected tissues were compared in obese (ob/ob) and lean (+/?) C57BL/6J mice. When 5-, 10- and 22-wk-old mice were administered 1.2 mumol 65Zn by stomach tube the apparent absorption of 65Zn by obese mice was 1.5, 2.2 and 3.9 times higher, respectively, than that in age-matched lean mice. Retention of orally administered 65Zn after 96 h was also substantially higher in obese mice than in lean mice. To assess the possible influences of hyperphagia and intestinal hypertrophy on the enhanced apparent absorption of 65Zn by obese mice food intake by an additional group of obese mice was restricted to that of age-matched lean controls. When actual absorption of zinc was determined according to the method of Heth and Hoekstra, groups of ad libitum--fed obese, pair-fed obese and lean mice absorbed 38, 32 and 18% of administered 65Zn, respectively. In contrast, the rate of 65Zn excretion 2-6 d after oral or subcutaneous administration of the metal was similar for obese and lean mice. Unrestricted and pair-fed obese mice had significantly lower percentages of carcass 65Zn present in skin, muscle plus bone, spleen and testes and higher percentages present in liver, small intestine and adipose tissue than lean mice.(ABSTRACT TRUNCATED AT 250 WORDS)     

Update on non-alcoholic fatty liver disease in children

Non-alcoholic fatty liver disease (NAFLD) is probably the most common cause of liver disease in the pediatric community. It is closely associated with obesity and insulin resistance. NAFLD may lead to non-alcoholic steatohepatitis (NASH). Although NASH is a prerequisite for the definition of NAFLD in adults and children, distinct differences are often apparent in the extent or location of fat, inflammation and fibrosis. Confirmation of the diagnosis of NAFLD can usually be achieved by imaging studies; however, staging the disease requires a liver biopsy. Current treatment relies on weight loss and exercise, although various insulin-sensitizing agents, antioxidants and medications appear promising. The aim of this review is to summarize what is known about pediatric NAFLD in terms of prevalence, pathogenesis, diagnosis, histology and treatment.     

鸡蛋摄入与非酒精性脂肪肝病患病风险的病例对照研究

目的 探讨鸡蛋摄入与非酒精性脂肪肝病（non-alcoholic fatty liver disease,NAFLD）患病风险的关系,为NAFLD的防控提供流行病学依据。 方法 收集2015年4月―2017年8月在南平市第一医院体检中心进行健康检查的体检者数据,以腹部彩超确诊的541名病例和按年龄性别随机抽取的541名对照进行病例对照研究。采用统一编制的结构式调查问卷及半定量食物频数问卷面对面调查研究对象的一般行为特征及膳食摄入情况。多因素非条件Logistic回归分析模型计算OR值及其95%CI,探索鸡蛋摄入与NAFLD患病风险的关系。 结果 与每天摄入鸡蛋相比,鸡蛋摄入频率为0患NAFLD的风险增高,其调整的OR值及其95% CI为1.86（95% CI：1.10~3.15）。敏感分析结果及亚组分析均显示从不摄入鸡蛋仍然是NAFLD的危险因素。 结论 从不摄入鸡蛋可能增高NAFLD的患病风险。     

Predictors of non-alcoholic fatty liver disease in obese children

OBJECTIVE: To evaluate predictors of non-alcoholic fatty liver disease (NAFLD) in obese children. DESIGN: Cross-sectional study. SUBJECTS: Two hundred and sixty-eight obese children not consuming alcohol and without hepatitis B or C were consecutively studied at an auxology clinic. MEASUREMENTS: Alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl-transferase (GGT), cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglycerides, uric acid, glucose, glucose during oral glucose tolerance testing (OGTT), insulin, insulin during OGTT, insulin resistance as estimated by homeostasis model assessment (HOMA), C-reactive protein (CRP), and systolic and diastolic blood pressure were measured. Fatty liver was diagnosed by ultrasonography using standard criteria. Univariable and multivariable logistic regression was used to evaluate predictors of NAFLD. All predictors except gender and pubertal status were modeled as continuous variables. RESULTS: NAFLD was detected in 44% of obese children. At univariable analysis, male gender, Z-score of body mass index (BMI) (Z-BMI), ALT, AST, GGT, triglycerides, uric acid, glucose, glucose during OGTT, insulin, insulin during OGTT, HOMA, CRP and systolic blood pressure were predictors of NAFLD, whereas HDL-cholesterol and late-pubertal status were predictors of the normal liver. At multivariable analysis, however, only Z-BMI, ALT, uric acid, glucose during OGTT and insulin during OGTT were independent predictors of NAFLD. CONCLUSION: Z-BMI, ALT, uric acid, glucose during OGTT and insulin during OGTT are independent predictors of NAFLD in Italian obese children, with most of the prediction explained by ALT and Z-BMI.     

A moderate weight reduction through dietary intervention decreases hepatic fat content in patients with non-alcoholic fatty liver disease (NAFLD): a pilot study

Purpose

As a diet rich in fructose and an impaired intestinal barrier function have been proposed to be risk factors for the development of non-alcoholic fatty liver disease (NAFLD), the aim of the present pilot study was to determine whether a dietary intervention focusing on a reduction of fructose intake (?50 % in comparison with baseline) has a beneficial effect on liver status.

Methods

A total of 15 patients with NAFLD were enrolled in the study of which 10 finished the study. Fructose and total nutrient intake were assessed using a diet history. At baseline and after 6 months liver status and markers of intestinal barrier function as well as plasminogen activator inhibitor (PAI-) 1 concentration were determined in plasma.

Results

Hepatic lipid content and transaminases in plasma as well as body mass index and some parameters of glucose metabolism (e.g., fasting plasma insulin) were significantly lower at the end of the intervention when compared to baseline. Whereas the dietary intervention had no effect on the prevalence of bacterial overgrowth, orocecal transit time and the intestinal permeability or blood ethanol levels endotoxin and PAI-1 concentration in plasma were significantly lower at the end of 6 months intervention period than at baseline.

Conclusions

Taken together, our results indicate that a dietary intervention focusing only on one dietary parameter like fructose may help to decrease intrahepatic fat content of NAFLD patients.     

Consequences of non-alcoholic fatty liver disease still unclear

There is still a lack of clarity concerning the long-term outcome and severity of non-alcoholic fatty liver disease (NAFLD). Results of a study recently conducted by the National Health and Nutrition Examination Survey (NHANES) showed that patients with NAFLD diagnosed 30 years ago did not experience decreased survival when compared with persons without NAFLD. But questions arise about the diagnostic methods in this study and the consequences for daily practice. Is NAFLD really a disease, and what is the diagnostic method of choice?     

The development of cold-induced thermogenesis and the structure of brown adipocyte mitochondria in genetically-obese (ob/ob) mice

The onset of cold-induced thermogenesis was studied in a strain of mice which produced among their offspring genetically-obese (ob/ob) individuals. A thermogenic response was present in a majority by day 5 after birth. The thermogenic response to cold was measured on days 5, 10 or 15 after birth, and the animals reared and the onset of obesity noted. The correlation between the subsequent development of obesity and a poor thermogenic response in early life was low. A poor thermogenic response at day 15 was associated with the presence in brown adipocytes of mitochondria with disordered internal structures. At day 42 both non-obese and obviously-obese mice showed a similar thermogenic response to moderate cold exposure. It would seem that in this strain of mice disordered internal mitochondrial structure in brown adipose tissue is associated with a poor thermogenic response to cold, but not invariably with the subsequent onset of obesity.     

The meal pattern of genetically obese (ob/ob) mice

The purpose of this investigation was to determine the meal pattern that characterizes the increased food intake of the ob/ob mouse. The major result was that obese mice ate larger and less frequent meals than lean mice during the dark phase of the light-dark cycle. There was a sex difference in that obese females ate the largest meals. To investigate the possibility that the different meal patterns observed in obese and lean mice was an artifact of the temporal criterion used to define a minimal intermeal interval, the meal patterns of obese and lean male mice were analyzed using two temporal criteria, 1 min and 5 min, and a behavioral criterion, the behavioral sequence of satiety. This analysis demonstrated that obese mice ate larger meals than lean mice whenever the criterion for an intermeal interval included the behavioral sequence of satiety. The mechanisms responsible for the increased meal size in obese mice are not known, but we suggest that preabsorptive satiety mechanisms may be less potent in obese mice.