Treating nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is a chronic illness with multiple consequences. The spectrum of disease ranges from simple steatosis, with benign prognosis, to a potentially progressive form, nonalcoholic steatohepatitis, which may lead to liver fibrosis and cirrhosis, leading to an increase in morbidity and mortality. Furthermore, hepatocellular carcinoma incidence in NAFLD is comparable with that observed in hepatitis C-infected patients once cirrhosis is established. Current therapy is limited to lifestyle changes and control of associated metabolic disorders; however, new treatments are on the way from basic research to bedside. A review of the current literature on treatment of nonalcoholic fatty liver disease is presented in this article.     

Current concepts in the pathogenesis of nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized cause of chronic liver disease, representing the leading cause of hepatology referral in some centres. However, its pathophysiology is not completely understood. Insulin resistance is one of the major mechanisms involved in disease prevalence and progression. Owing to the lack of an effective pharmacological therapy, recommendations on treatment are scarce and are based mainly on lifestyle changes, including diet and exercise. A review of the current literature on pathogenesis of NAFLD is presented in this article.     

Visceral fat accumulation and insulin resistance are important factors in nonalcoholic fatty liver disease

Background Nonalcoholic fatty liver diseases are often associated with obesity, insulin resistance, and excessive visceral fat accumulation. The aims of this study were (1) to evaluate the relationship between the severity of fatty liver and visceral fat accumulation in nonalcoholic fatty liver diseases, and (2) to investigate the relationships of fatty liver with biochemical data and insulin resistance. Methods One hundred twenty-nine subjects (63 women) with fatty liver diagnosed by ultrasonography were enrolled. Subjects positive for hepatitis B virus, hepatitis C virus, or autoimmune antibodies and those whose alcohol intake was over 20 g/day were excluded. The visceral fat area at the umbilical level and the liver–spleen ratio were evaluated by computed tomography. Results The severity of fatty liver evaluated by ultrasonography showed a significant positive relationship with the visceral fat area and waist circumstance (fatty liver severity: mild, 92.0 ± 30.9 cm²; moderate, 122.1 ± 32.6 cm²; severe, 161.0 ± 48.4 cm²; P < 0.0001). The visceral fat area and liver–spleen ratio were negatively correlated (r = −0.605, P < 0.0001). The severity of fatty liver showed strong positive relationships with serum aspartate aminotransferase, alanine aminotransferase, fasting plasma glucose, fasting plasma insulin, and insulin resistance. The severity of fatty liver was positively related to the visceral fat area in 49 nonobese subjects (body mass index <25). Conclusions The severity of fatty liver was positively correlated with visceral fat accumulation and insulin resistance in both obese and nonobese subjects, suggesting that hepatic fat infiltration in nonalcoholic fatty liver disease may be influenced by visceral fat accumulation regardless of body mass index.     

Liver steatosis,but not fibrosis,is associated with insulin resistance in nonalcoholic fatty liver disease

Background To address the hypothesis that liver steatosis causes systemic insulin resistance, we sought to determine the liver histological feature that most strongly contributes to insulin resistance in patients with nonalcoholic fatty liver disease (NAFLD). Methods Liver biopsy specimens were obtained from 131 patients with clinically suspected NAFLD. The stage, grade of nonalcoholic steatohepatitis (NASH), and level of steatosis were scored and analyzed in relation to the homeostasis model assessment of insulin resistance (HOMA-IR) and the metabolic clearance rate (MCR), measured using the glucose clamp method. Results In the univariate analysis, the degree of hepatic steatosis (r = 0.458, P < 0.001), stage (r = 0.360, P < 0.001), and grade (r = 0.349, P < 0.01) of NASH were significantly correlated with the HOMA-IR. Multiple regression analysis adjusting for age, sex, body mass index, and each histological score showed that steatosis was significantly and independently associated with HOMA-IR (coefficient = 1.42, P < 0.001), but not with the stage (coefficient = 0.33, P = 0.307) or grade (coefficient = 0.67, P = 0.134) of NASH. Similar independent relationships were observed between steatosis and MCR, but the relationship was weaker (coefficient = −0.98, P = 0.076). Conclusions Steatosis of the liver, but not the stage or the grade of NASH, is associated with insulin resistance in patients with NAFLD.     

Impact of body weight,diet and lifestyle on nonalcoholic fatty liver disease

Nonalcoholic steatohepatitis is part of the broader spectrum of nonalcoholic fatty liver disease, strongly associated with insulin resistance, obesity and the metabolic syndrome. Its increasing prevalence appears to be closely related to the increased frequency of overweight or obesity; which is associated with changes in dietary habits, including an increased consumption of hypercaloric food and saturated fat, often concurrent with decreased activity and energy expenditure. Weight loss through dieting and increasing energy expenditure through the practice of regular exercise has been shown to be effective in improving nonalcoholic fatty liver disease/nonalcoholic steatohepatitis, and is considered the mainstay of treatment. The effectiveness of these lifestyle interventions seems to rely chiefly on an improvement in insulin sensitivity. At present, disease management using a multidisciplinary team is probably pivotal for patient-centered quality of care.     

多囊卵巢综合征患者非酒精性脂肪性肝病的发病情况及特点分析

目的探讨多囊卵巢综合征（PCOS）患者非酒精性脂肪性肝病（NAFLD）的发生情况和临床特点。方法对306例PCOS患者行基础内分泌、口服糖耐量试验及胰岛素释放试验、肝功、血脂、肝脏超声等检查。分析NAFLD的发病情况及特点。结果 NAFLD发生率为30.7%（94/306）;NAFLD发病率随体质量指数（BMI）和年龄的增加而升高。PCOS合并NAFLD者空腹血糖、空腹胰岛素、口服葡萄糖2h后血糖及胰岛素水平、稳态模型评估（HOMA-IR）、谷丙转氨酶（ALT）、谷草转氨酶（AST）、TC、TG、LDL-C、BMI、腰围、腰臀比,均显著高于不合并NAFLD者（P均〈0.05）;而量化胰岛素敏感指数（QUICK）、HDL-C则显著低于不合并NAFLD者（P均〈0.05）。PCOS合并NAFLD者胰岛素抵抗、腹型肥胖、糖耐量异常、糖尿病、肝功异常、血脂异常、高血压病及代谢综合征的患病率显著高于不合并NAFLD者（P〈0.05）。结论 PCOS伴NAFLD发病率较高;其发病率与BMI和年龄呈正相关;PCOS伴NAFLD多存在胰岛素抵抗、代谢异常;超重及腹型肥胖是PCOS患者NAFLD的主要危险因素。     

Causal relationship of hepatic fat with liver damage and insulin resistance in nonalcoholic fatty liver

Background and Aims

Nonalcoholic fatty liver disease is epidemiologically associated with hepatic and metabolic disorders. The aim of this study was to examine whether hepatic fat accumulation has a causal role in determining liver damage and insulin resistance.

Methods

We performed a Mendelian randomization analysis using risk alleles in PNPLA3, TM6SF2, GCKR and MBOAT7, and a polygenic risk score for hepatic fat, as instruments. We evaluated complementary cohorts of at‐risk individuals and individuals from the general population: 1515 from the liver biopsy cohort (LBC), 3329 from the Swedish Obese Subjects Study (SOS) and 4570 from the population‐based Dallas Heart Study (DHS).

Results

Hepatic fat was epidemiologically associated with liver damage, insulin resistance, dyslipidemia and hypertension. The impact of genetic variants on liver damage was proportional to their effect on hepatic fat accumulation. Genetically determined hepatic fat was associated with aminotransferases, and with inflammation, ballooning and fibrosis in the LBC. Furthermore, in the LBC, the causal association between hepatic fat and fibrosis was independent of disease activity, suggesting that a causal effect of long‐term liver fat accumulation on liver disease is independent of inflammation. Genetically determined hepatic steatosis was associated with insulin resistance in the LBC and SOS. However, this association was dependent on liver damage severity. Genetically determined hepatic steatosis was associated with liver fibrosis/cirrhosis and with a small increase in risk of type 2 diabetes in publicly available databases.

Conclusion

These data suggest that long‐term hepatic fat accumulation plays a causal role in the development of chronic liver disease.     

非酒精性脂肪性肝病与代谢综合征指标变化的相关性分析

目的探讨中老年人群中非酒精性脂肪性肝病(NAFLD)与代谢综合征相关指标变化的关系。方法收集2010—2011年暨南大学附属第一医院40岁以上体检人群腹部B超检查的数据,用多因素Logistic回归分析体重指数(BMI)、空腹血糖(FBG)、三酰甘油(TG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)及低密度脂蛋白胆固醇(LDL-C)、丙氨酸转氨酶(ALT)、血尿酸(UA)的变化值与NAFLD变化的关系。结果 2年内男性组和女性组NAFLD检出率都在增加,男性新增NAFLD总检出率为13.7%,明显高于女性新增NAFLD检出率7.5%(P<0.05);男性和女性的NAFLD消减率都是5.5%,且峰值都在60岁年龄组;BMI变化值与新增NAFLD密切正相关,BMI变化值的OR=1.474(95%CI 1.184～1.811),而TG和FBG的变化值与新增NAFLD无相关性;TG和BMI的变化值与NAFLD的消减呈负相关,TG变化值的OR=0.653(95%CI 0.508～0.838),BMI变化值的OR=0.628(95%CI 0.460～0.857),而FBG变化值未发现与NAFLD消减有相关性。结论 BMI变化值与NAFLD发生有密切相关性,TG和BMI的变化值与NAFLD的消减呈负相关,是影响NAFLD变化的重要因素之一。     

强肝胶囊对非酒精性脂肪性肝病患者胰岛素抵抗指数和肝纤维化评分的影响

目的观察强肝胶囊对非酒精性脂肪性肝病(NAFLD)患者肝纤维化评分和胰岛素抵抗指数的影响。方法选取2014年8月-2015年7月在上海市第八人民医院就诊的NAFLD患者85例,随机分为治疗组(n=45)和对照组(n=40)。治疗组给予强肝胶囊,对照组给予多烯磷脂酰胆碱胶囊,2组疗程均为24周。观察2组治疗前后血清转氨酶(AST、ALT)、稳态模型胰岛素抵抗指数(HOMA-IR)以及NAFLD肝纤维化评分(NAFLDFS)的变化。计量资料组间比较采用成组t检验,组内治疗前后比较采用配对t检验;计数资料组间比较采用χ2检验。结果 2组治疗后ALT、AST水平均较同组治疗前明显改善,差异均有统计学意义(P值均0.05);与治疗前比,治疗组HOMA-IR、NAFLDFS治疗后均明显下降,差异均有统计学意义(3.58±0.85 vs 2.48±0.78,t=6.40,P0.05;-1.78±1.24 vs-2.35±0.98,t=2.40,P0.05)。2组间治疗后比较,治疗组HOMA-IR、NAFLDFS较对照组显著下降,差异均有统计学意义(2.48±0.78 vs 3.09±0.89,t=3.36,P0.01;-2.35±0.98 vs-1.48±1.08,t=3.80,P0.01)。整个疗程未见明显不良反应。结论强肝胶囊不仅能降低血清转氨酶水平,还可改善胰岛素抵抗和减轻NAFLD患者肝纤维化程度。     

Bile acids and insulin resistance: implications for treating nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease is characterized by an accumulation of excess triglycerides in hepatocytes, and insulin resistance is now considered the fundamental operative mechanism throughout the prevalence and progression of the disease. Besides their role in dietary lipid absorption and cholesterol homeostasis, evidence has accumulated that bile acids are also signaling molecules that play two important roles in glucose and lipid metabolism: in the nuclear hormone receptors as farnesoid X receptors (FXR), as well as ligands for G‐protein‐coupled receptors TGR5. The activated FXR‐SHP pathway regulates the enterohepatic recycling and biosynthesis of bile acids and underlies the down‐regulation of hepatic fatty acid and triglyceride biosynthesis and very low density lipoprotein production mediated by sterol‐regulatory element‐binding protein‐1c. The bile acid‐TGR5‐cAMP‐D2 signaling pathway in human skeletal muscle in the fasting–feeding cycle increases energy expenditure and prevents obesity. Therefore, a molecular basis has been provided for a link between bile acids, lipid metabolism and glucose homeostasis, which can open novel pharmacological approaches against insulin resistance and nonalcoholic fatty liver disease.     

Relationship between serum uric acid level and nonalcoholic fatty liver disease in type 2 diabetes patients

This study aimed to investigate the association between serum uric acid (SUA) level and nonalcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes (T2DM).T2DM patients hospitalized in the Department of Hepatology, Yantai Qishan Hospital, between April 2012 and December 2018 were classified into the NAFLD group and the non-NAFLD group. Clinical data, glucose and lipid metabolism biomarkers, and liver and kidney function parameters were retrospectively collected.Five hundred eighty-three T2DM patients met the inclusion and exclusion criteria; 227 patients were included in the non-NAFLD group and 356 patients were included in the NAFLD group. Multiple linear regression analyses showed that SUA was positively correlated with body mass index (P = .003), triglycerides (P = .009), aspartate aminotransferase (P = .036), and alanine aminotransferase (P = .038) and negatively correlated with estimated glomerular filtration rate (P < .001) in T2DM patients. Multivariate regression analyses demonstrated that after adjusting for confounding factors, the SUA tertile was still significantly associated with NAFLD occurrence in T2DM patients (P for trend = .008). With reference to SUA tertile I, the odds ratios for NAFLD in the SUA tertile II and tertile III groups were 1.729 (95% confidence interval [CI]: 1.086–2.753) and 2.315 (95% CI: 1.272–4.213), respectively.The level of SUA in T2DM patients was associated with the occurrence of NAFLD. Elevated SUA was associated with a significantly increased prevalence of NAFLD. The SUA level was an independent risk factor for NAFLD occurrence in patients with T2DM.     

Insulin resistance in development and progression of nonalcoholic fatty liver disease

Although insulin resistance(IR)is strongly associated with nonalcoholic fatty liver disease(NAFLD),the association of IR and NAFLD is not universal and correlation between IR and severity of NAFLD is still controversial.In this review,we summarize recent evidence that partially dissociates insulin resistance from NAFLD.It has also been reported that single-nucleotide polymorphisms in the diacylglycerol acyltransferase gene,rather than IR,account for the variability in liver fat content.Polymorphisms of the patatin-like phospholipase 3 gene have also been reported to be associated with NAFLD without metabolic syndrome,which suggests that genetic conditions that promote the development of fatty changes in the liver may occur independently of IR.Moreover,environmental factors such as nutrition and physical activity as well as small intestinal bacterial overgrowth have been linked to the pathogenesis of NAFLD,although some of the data are conflicting.Therefore,findings from both genetically engineered animal models and humans with genetic conditions,as well as recent studies that have explored the role of environmental factors,have confirmed the view that NAFLD is a polygenic disease process caused by both genetic and environmental factors.Therefore,IR is not the sole predictor of the pathogenesis of NAFLD.     

Interaction of Type 2 diabetes and nonalcoholic fatty liver disease

Evauation of: Kasturiratne A, Weerasinghe S, Dassanayake A et al. Influence of non-alcoholic fatty liver disease on the development of diabetes mellitus. J. Gastroenterol. Hepatol. 28(1), 142–147 (2013).

It has been a few decades that Type 2 diabetes has been clearly linked to the development and progression of nonalcoholic fatty liver disease (NAFLD). In a recent study reported by Kastuiratne et al., the reverse scenario is also reported. In this study, a cohort of Sri Lankan adults were evaluated for NAFLD by ultrasound and for the presence of Type 2 diabetes. Those without diabetes at baseline were followed prospectively for 3 years and assessed for incident diabetes. On multivariate analysis, after adjustment for a number of factors (age, impaired fasting glucose, BMI, waist circumference, elevated ALT, family history of diabetes and presence of hypertension and hyperlipidemia), NAFLD was the only predictor of incident diabetes in those with and without impaired fasting glucose at baseline. This study adds to the growing evidence connecting NAFLD to Type 2 diabetes and highlights the importance of its recognition in an effort to target those at the highest risk of diabetes for lifestyle and pharmacologic intervention.     

小檗碱对非酒精性脂肪肝胰岛素抵抗及血清脂联素的影响

目的观察小檗碱对非酒精性脂肪肝（nonalcoholic fatty liver disease,NAFLD）胰岛素抵抗及血清脂联素（adiponectin,APN）的影响。方法选取我院门诊就诊的NAFLD患者68例,分为对照组（30例）和治疗组（38例）;健康体检者30例为健康组。治疗前分别测定NAFLD组及健康组的APN、血糖、血脂、空腹胰岛素（FINS）、胰岛素抵抗指数（HOMA-IR）、胰岛素敏感性指数（HOMA-IAI）及肝功能水平的变化。治疗组予小檗碱0.5g/次,3次/d,连续3月;对照组予低脂饮食,治疗3月后测定上述各指标。结果 NAFLD患者空腹血糖（FPG）、总胆固醇（TC）、三酰甘油（TG）、低密度脂蛋白胆固醇（LDL-C）、FINS、HOMA-IR及体质量指数（BMI）均明显升高,胰岛素敏感性降低,APN水平明显减少（P〈0.05）。口服小檗碱治疗后,治疗组FPG、TC、TG、LDL-C、FINS、HOMA-IR及BMI均明显下降,胰岛素敏感性,APN水平则明显升高（P〈0.05）,对照组各指标无变化（P〉0.05）。结论小檗碱治疗后,NAFLD患者血清APN水平明显升高,改善了胰岛素敏感性,降低了胰岛素抵抗。     

非酒精性脂肪性肝病胰岛素抵抗程度与全血细胞计数的相关性

目的探讨伴或不伴2型糖尿病(T2DM)的非酒精性脂肪性肝病(NAFLD)胰岛素抵抗(IR)程度与全血细胞计数各参数的相关性。方法选取糖耐量正常并除外糖尿病史的单纯NAFLD患者102例,T2DM合并NAFLD患者104例,正常对照104例为研究对象,测定空腹血糖(FPG)、空腹胰岛素(FINS)和全血细胞计数,分析胰岛素抵抗指数(HOMA-IR)与全血细胞计数各参数的相关性。结果 T2DM合并NAFLD患者IR及全血细胞计数异常程度较单纯NAFLD患者更重;相关性研究表明男性HOMA-IR与WBC、NEU、LYM、RBC、HGB、HCT呈正相关,女性HOMA-IR与WBC、NEU、LYM、MID、RBC、HGB、HCT呈正相关。结论 NAFLD时白细胞参数和红细胞参数的变化与IR密切相关,T2DM的存在加重了IR对上述血细胞参数的影响。全血细胞计数可以作为反映NAFLD患者IR程度的一种简单实用的检验指标。     

Effects of nonalcoholic fatty liver disease on the development of metabolic disorders

Background and Aim: Nonalcoholic fatty liver disease (NAFLD) is considered to be the liver component of metabolic syndrome. However, the impact of NAFLD on metabolic syndrome is unclear. The aim of this study was to explore the influence of NAFLD on the development of metabolic disorders. Methods: Patients with NAFLD and an age, sex, and occupation‐matched control group were recruited from employees of Bao‐Steel Group (Shanghai, China) who had received medical check‐ups biennially between 1995 and 2002. Anthropometric and laboratory data, and incidence of metabolic disorders were assessed at baseline and at follow‐up of at least 4 years. SPSS 11.5 was used for statistical analysis. Results: The study consisted of 358 patients (326 men and 32 women) and 788 matched controls (711 men and 77 women) with a similar mean age of 39.0 years and median follow‐up of 6 years. At the end of follow‐up, incidence of obesity (47.6% vs 19.5%), hypertension (69.6% vs 16.3%), hypertriglyceridemia (39.1% vs 16.3%), hypercholesterolemia (24.5% vs 17.3%), impaired fasting glucose (IFG) (25.1% vs 11.6%), diabetes mellitus (20.3% vs 5.2%) and multiple metabolic disorders (MMD) (56.3% vs 16.3%) were significantly higher in the fatty liver group than the control group. Interestingly, the mean alanine aminotransferase (ALT) level in patients with fatty liver significantly decreased at follow‐up compared with baseline (28.56 ± 18.86 vs 31.51 ± 18.34 U/L, P < 0.05). To separate the effects of obesity from fatty liver, the subjects were re‐classified according to the presence of obesity and fatty liver at baseline. The incidence of hypertension (61.1% vs 41.3%), hypertriglyceridemia (38.1% vs 15.0%), hypercholesterolemia (29.9% vs 16.6%), IFG (21.3% vs 10.0%) and diabetes (11.1% vs 4.3%) were significantly higher in the fatty liver group without obesity (n = 84) than in the group with without fatty liver or obesity (n = 614). In addition, the incidence of hypertension (72.9% vs 57.4%), hypertriglyceridemia (39.4% vs 22.7%) and diabetes (23.2% vs 8.4%) was higher in the group with fatty liver and obesity (n = 274) than in the group with obesity alone (n = 174). Conclusions: The presence of NAFLD might predict the development of metabolic disorders due to insulin resistance, rather than obesity itself. ALT levels decreased over time in patients with fatty liver.     

Sampling variability of liver biopsy in nonalcoholic fatty liver disease

BACKGROUND & AIMS: In nonalcoholic fatty liver disease (NAFLD), the distinction between steatosis and steatohepatitis (NASH) and the assessment of the severity of the disease rely on liver histology alone. The aim of this study was to assess the sampling error of liver biopsy and its impact on the diagnosis and staging of NASH. METHODS: Fifty-one patients with NAFLD underwent percutaneous liver biopsy with 2 samples collected. The agreement between paired biopsy specimens was assessed by the percentage of discordant results and by the kappa reliability test. RESULTS: No features displayed high agreement; substantial agreement was only seen for steatosis grade; moderate agreement for hepatocyte ballooning and perisinusoidal fibrosis; fair agreement for Mallory bodies; acidophilic bodies and lobular inflammation displayed only slight agreement. Overall, the discordance rate for the presence of hepatocyte ballooning was 18%, and ballooning would have been missed in 24% of patients had only 1 biopsy been performed. The negative predictive value of a single biopsy for the diagnosis of NASH was at best 0.74. Discordance of 1 stage or more was 41%. Six of 17 patients with bridging fibrosis (35%) on 1 sample had only mild or no fibrosis on the other and therefore could have been under staged with only 1 biopsy. Intraobserver variability was systematically lower than sampling variability and therefore could not account for most of the sampling error. CONCLUSIONS: Histologic lesions of NASH are unevenly distributed throughout the liver parenchyma; therefore, sampling error of liver biopsy can result in substantial misdiagnosis and staging inaccuracies.