Second-hand smoke stimulates lipid accumulation in the liver by modulating AMPK and SREBP-1

Prevalence and determinants of non-alcoholic fatty liver disease in lifelines: A large Dutch population cohort

Background & aims

Non-alcoholic fatty liver disease is an increasing health issue that develops rather unnoticed with obesity, type 2 diabetes mellitus and metabolic syndrome. We investigated prevalence, determinants and associated metabolic abnormalities of non-alcoholic fatty liver disease in the largest population-based cohort to date.

Methods

Biochemical characteristics, type 2 diabetes mellitus and metabolic syndrome were determined in the Lifelines Cohort Study (N = 167,729), a population-based cohort in the North of the Netherlands. Non-alcoholic fatty liver disease was defined as Fatty Liver Index (FLI)≥60. Exclusion criteria were age <18 years, immigrants, missing data to assess FLI and metabolic syndrome, excessive alcohol use, previous-diagnosed hepatitis or cirrhosis and non-fasting blood sampling.

Results

Out of 37,496 included participants (median age 44 years, 62.1% female), 8,259 (22.0%) had a FLI≥60. Individuals with a FLI≥60 were more often male, older, obese, had higher levels of hemoglobinA1c, fasting glucose, liver enzymes, total cholesterol, low-density lipoprotein cholesterol, triglycerides, c-reactive protein and leucocytes and lower high-density lipoprotein cholesterol (all P<0.0001). Participants with a FLI≥60 showed higher prevalence of type 2 diabetes mellitus (9.3% vs. 1.4%), metabolic syndrome (54.2% vs. 6.2%), impaired renal function (20.1% vs. 8.7%) and cardiovascular disease (4.6% vs. 1.6%) (all P<0.0001). Multivariable logistic analysis showed that smoking, hemoglobin, leucocytes, c-reactive protein, platelets, alanine aminotransferase, alkaline phosphatase, albumin, impaired renal function (OR 1.27, 95%CI 1.15–1.41), metabolic syndrome (OR 11.89, 95%CI 11.03–12.82) and its individual components hyperglycemia (OR 2.53, 95%CI 2.34–2.72), hypertension (OR 1.89, 95%CI 1.77–2.01) and reduced high-density lipoprotein cholesterol (OR 3.44, 95%CI 3.22–3.68) were independently associated with suspected non-alcoholic fatty liver disease (all P<0.0001).

Conclusion

Twenty-two percent (22.0%) of the population in the North of the Netherlands is suspected to suffer from non-alcoholic fatty liver disease, coinciding with a significant increased risk of type 2 diabetes mellitus, metabolic syndrome, cardiovascular disease and impaired renal function.

Evaluating the Influence of Side Stream Cigarette Smoke at an Early Stage of Non-Alcoholic Steatohepatitis Progression in Mice

Side stream cigarette smoke (SSCS) is known to be as harmful and hazardous to human health as is active smoking. In this study, we investigated the relationship between the exposure to SSCS and its stimulatory and subacute effects on the progression of non-alcoholic steatohepatitis (NASH). A methionine and choline-deficient plus high fat (MCDHF) diet was administered to C57BL/6 mice for 6 weeks. During the first three weeks of MCDHF diet feeding, each diet group was exposed to SSCS (0, 20, 40 μg/L) or fresh air for 2 hrs per day and 5 days per week. Additional experiments were performed by increasing the concentration (0, 30, 60 μg/L) and exposure time (6 hours per day) of SSCS. According to histopathologic analysis and serum levels of Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST), there were no differences in hepatic fat deposition, fibrosis, apoptosis or liver damage in MCDHF-fed mice based on SSCS exposure. There were also no differences in the expression of inflammation-, oxidative stress- or fibrosis-related genes between MCDHF-fed mice with or without SSCS exposure. Therefore, it is concluded that SSCS with current exposure amounts does not have additive detrimental effects on the early stage of NASH.

Thirdhand Smoke: New Evidence, Challenges, and Future Directions

Thirdhand smoke (THS) is the contamination that persists after secondhand tobacco smoke has been emitted into air. It refers to the tobacco-related gases and particles that become embedded in materials, such as the carpet, walls, furniture, blankets, and toys. THS is not strictly smoke, but chemicals that adhere to surfaces from which they can be released back into the air, undergo chemical transformations and/or accumulate. Currently, the hazards of THS are not as well documented as the hazards of secondhand smoke (SHS). In this Perspective, we describe the distribution and chemical changes that occur as SHS is transformed into THS, studies of environmental contamination by THS, human exposure studies, toxicology studies using animal models and in vitro systems, possible approaches for avoiding exposure, remediation of THS contamination, and priorities for further research.

Tobacco carcinogen induces both lung cancer and non-alcoholic steatohepatitis and hepatocellular carcinomas in ferrets which can be attenuated by lycopene supplementation

Early epidemiologic studies have reported that tobacco smoking, which is causally associated with liver cancer, is an independent risk factor for non-alcoholic fatty liver diseases (NAFLD). Lycopene from tomatoes has been shown to be a potential preventive agent against NAFLD and hepatocellular carcinoma (HCC). In the present study, we investigated whether the tobacco carcinogen 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induces lesions in both lungs and livers of ferrets with or without lycopene intervention. Male ferrets (6 groups, n = 8-10) were treated either with NNK (50 mg/kg BW, i.p., once a month for four consecutive months) or saline with or without dietary lycopene supplementation (2.2 and 6.6 mg/kg BW/day, respectively) for 26 weeks. Results demonstrate that NNK exposure results in higher incidences of lung tumors, HCC and steatohepatitis (which is characterized by severe inflammatory cell infiltration with concurrent fat accumulation in liver, hepatocellular ballooning degeneration and increased NF-κB expression), as well as elevations in bilirubin and AST levels in ferrets. Lycopene supplementation at two doses prevented NNK-induced expressions of α7 nicotinic acetylcholine receptor in the lung and NF-κB and CYP2E1 in the liver and attenuated the NNK-induced mortality and pathological lesions in both the lungs and livers of ferrets. The present study provided strong experimental evidence that the tobacco carcinogen NNK can induce both HCC and steatohepatitis in the ferrets and can be a useful model for studying tobacco carcinogen-associated NAFLD and liver cancer. Furthermore, lycopene could provide potential benefits against smoke carcinogen-induced pulmonary and hepatic injury.

Mainstream cigarette smoke accelerates the progression of nonalcoholic steatohepatitis by modulating Kupffer cell-mediated hepatocellular apoptosis in adolescent mice

Cigarette smoking in adolescents is considered to be a major cause of preventable morbidity and mortality. The purpose of this study is to investigate the role of mainstream cigarette smoke (MSCS) on the progression of nonalcoholic steatohepatitis in adolescents. Three-week-old C57BL/6 mice were fed either a methionine and choline-deficient plus high fat (MCDHF) diet for 6 weeks. Each group was exposed to MSCS (300, 600 ug/L) or fresh air for 2h per day during the first 3 weeks of MCDHF diet feeding. MSCS increased MCDHF diet-induced NASH by increasing serum ALT/AST levels, steatosis, inflammation, and fibrosis. Furthermore, MSCS was associated with the degree of oxidative stress and hepatocellular apoptosis in NASH mice, but not prominent in controls. In vitro, cigarette smoke extract (CSE) activated Kupffer cells (KCs) to release inflammatory cytokines and oxidative stress, which induced hepatocellular apoptosis. In conclusion, MSCS exposure accelerates the progression and severity of NASH by modulating KC-mediated hepatocellular apoptosis. Our results support the regulation of CS in adolescents with steatohepatitis.

Murine models of cardiovascular comorbidity in chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) have an increased risk for cardiovascular disease (CVD). Currently, COPD patients with atherosclerosis (i.e., the most important underlying cause of CVD) receive COPD therapy complemented with standard CVD therapy. This may, however, not be the most optimal treatment. To investigate the link between COPD and atherosclerosis and to develop specific therapeutic strategies for COPD patients with atherosclerosis, a substantial number of preclinical studies using murine models have been performed. In this review, we summarize the currently used murine models of COPD and atherosclerosis, both individually and combined, and discuss the relevance of these models for studying the pathogenesis and development of new treatments for COPD patients with atherosclerosis. Murine and clinical studies have provided complementary information showing a prominent role for systemic inflammation and oxidative stress in the link between COPD and atherosclerosis. These and other studies showed that murine models for COPD and atherosclerosis are useful tools and can provide important insights relevant to understanding the link between COPD and CVD. More importantly, murine studies provide good platforms for studying the potential of promising (new) therapeutic strategies for COPD patients with CVD.

Nonalcoholic fatty liver disease severity is associated with the ratios of total cholesterol and triglycerides to high-density lipoprotein cholesterol

BACKGROUND

Limited data support the notion that lipid ratios are risk factors for nonalcoholic fatty liver disease (NAFLD). We evaluated the association between lipid ratios and NAFLD.

METHODS

This was a large population, cross-sectional, retrospective study. Data on NAFLD severity, blood pressure, fasting glucose, total cholesterol (TC), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-C) levels were obtained from 44,767 examinees at single health checkup center. The enrollees were stratified into four subgroups based on their TC/HDL-C and TG/HDL-C ratios. We used multivariate analyses to evaluate the odds between lipid ratios and NAFLD.

RESULTS

The prevalence rate of fatty liver in this study was 53.76%. In the baseline subgroup with the lowest TC/HDL-C and TG/HDL-C ratios, the prevalence of NAFLD, hypertension, and diabetes was lower than that of the other three subgroups. Patients with higher lipid ratios had a significantly greater risk for advanced NAFLD.

CONCLUSIONS

Adults with high TC/HDL-C or TG/HDL-C ratios, or both, have a greater risk for NAFLD, especially advanced NAFLD.

Neck circumference as an independent indicator to non-alcoholic fatty liver disease in non-obese men

Background

To investigate the relationship of the neck circumference (NC) with non-alcoholic fatty liver disease (NAFLD) in non-obese Chinese population.

Methods

Our data were obtained from a cross-sectional survey on the prevalence of metabolic diseases and risk factors in East China in 2014. Subjects with a BMI ≥ 18.5 kg/m² and < 25 kg/m² were considered normal weight. A total of 2668 participants aged 18–89 were identified for analysis. Anthropometric indices, biochemical parameters, clinical characteristics and abdominal ultrasound were measured. Independent predictors of NAFLD were identified by multiple logistic regressions.

Results

The overall prevalence of NAFLD was 10.94 % in this study population and men had a higher prevalence than women (19.89 % vs 7.48 %, P < 0.01). The mean NC was greater in NAFLD subjects compared with other groups in both genders (P < 0.01). NC was correlated to BMI, waist circumference, hip circumference, systolic blood pressure, diastolic blood pressure, insulin, HOMA-IR, triglycerides and ALT, regardless of sex. In the highest quartile of NC levels in men but not in women, the risks were substantially higher for NAFLD [odds ratio 2.18, (95 % confidence interval 1.16–4.13)] (P < 0.001 for trend) after adjusting for potential confounding factors.

Conclusion

NC was an independent indicator for NAFLD in normal weighted men.

Synergistic hepatotoxicity by cadmium and chlorpyrifos: disordered hepatic lipid homeostasis

Due to its extensive application, chlorpyrifos (CPF) has contaminated a diverse range of environmental substrates, fruits and vegetables. A number of studies have suggested that CPF may incur adverse effects on human health, including neurotoxicity, hepatotoxicity and endocrine disruption. Additionally, cadmium (Cd) is one of the most prevalent environmental heavy metals, as a result of considerable use in a wide spectrum of industrial fields. Exposure to Cd can cause several lesions in various organs, including the liver, kidneys and lungs. CPF and Cd often co-exist in the environment, food and crops, however, their joint exposure and potential synergistic toxicity are largely neglected and unrecognized. Our previous study characterized an interaction between CPF and Cd, which may occur via bonding between Cd2+ and the nitrogen atom in the pyridine ring of CPF, or the chelation between one Cd2+ and two CPF molecules. Our previous study also identified increased hepatotoxicity induced by CPF and Cd together compared with the individual compounds. In the present study, the effects of the concomitant exposure of CPF and Cd on lipid metabolism in hepatocytes was investigated. The results demonstrated an accumulation of lipids in hepatocytes, induced by the CPF and Cd complex, which was fundamentally distinct from its parental chemicals. Notably, the molecular mechanism by which the CPF-Cd complex significantly induced hepatic lipogenesis was revealed, elevating the concentrations of sterol regulatory element-binding protein-1 and fatty acid synthase. These findings pave the way for future studies in recognizing synergistic biological effects between pollutants.

In vitro effects of selenium on copper-induced changes in lipid metabolism of grass carp (Ctenopharyngodon idellus) hepatocytes

The present study was performed to evaluate the in vitro effects of selenium (Se) supplementation to prevent copper (Cu)-induced changes in lipid metabolism of hepatocytes from grass carp (Ctenopharyngodon idellus). Four groups (control and 100 μM Cu in combination with 0, 5, and 10 μM Se, respectively) were chosen. Compared with the control, activities of glucose 6-phosphatedehydrogenase, 6-phosphogluconate dehydrogenase, malic enzyme, and carnitine palmitoyltransferase I (CPT I) of all three Cu-exposed groups at 24 and 48 h were significantly greater. However, among three Cu-exposed groups, increasing Se concentration tended to increase activities of G6PD and ME at 24 h and 6PGD activity at 24 and 48 h but decreased CPT I activity at 24 h. Compared with the control, Cu exposure alone, or in combination with Se, downregulated mRNA levels of sterol regulatory element-binding protein-1 (SREBP-1c), fatty acid synthase (FAS), acetyl-CoA carboxylase, peroxisome proliferator activated receptor alpha (PPARα), CPT I, and hormone-sensitive lipase (HSL) at 24 h as well as SREBP-1c, FAS, and ACC mRNA levels at 48 h. However, upregulated mRNA levels of PPARα, CPT I, and HSL, as well as decreased triglyceride content, were recorded at 48 h. Thus, although toxic at greater levels, lower levels of Se provided significant protection against Cu-induced changes in lipid metabolism. For the first time, our study indicates the dose- and time-dependent effects of Se addition on changes in lipid metabolism induced by Cu in fish hepatocytes and provides new insights into Se-Cu interaction at both enzymatic and molecular levels.

Signal transductions and nonalcoholic fatty liver: a mini-review

Nonalcoholic fatty liver disease (NAFLD) is a common liver disease, and the incidence increases year by year. The pathogenesis of NAFLD is correlated with insulin resistant (IR), and oxidative stress which induces varied inflammatory cytokines (TNF-α, IL-1, IL-6, etc). Different signal transductions such as MAPK, NF-κB, AMPK, JAK2/STAT3, PPAR, PI3K/Akt, TLR were activated by the pathogenic factors to regulate correlative reactions. Thus, in-depth study of the signal transductions will probably provide new suitable solutions for the prevention and therapy of NAFLD.

Secondhand tobacco exposure is associated with nonalcoholic fatty liver disease in children

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of liver disease in children in the United States, and prevalence rates are rising. Smoking is associated with NAFLD, but the association of secondhand smoke exposure with NAFLD is unknown.

AIMS

To investigate the association of secondhand tobacco exposure with NAFLD in children.

METHODS

We surveyed parents/guardians of 304 children aged 3-12 years who had received an abdominal ultrasound at Penn State Hershey Medical Center. The survey addressed demographics, medical history, secondhand tobacco exposure, activity level, screen viewing time and other environmental exposures. A pediatric radiologist and sonographer reviewed the ultrasounds to grade the presence of bight liver compatible with NAFLD. We conducted logistic regression analysis to assess the association of secondhand tobacco exposure and NAFLD.

RESULTS

54% of eligible potential participants responded to the survey. Fatty liver was present in 3% of the children. Increasing child age was associated with increased odds of NAFLD (OR 1.63 95% CI 1.1, 2.4). Reported child obesity was associated with increased odds of NAFLD (OR 44.5 95% CI 5.3, 371.7). The rate of NAFLD was higher in the smoke exposed group (6.7% vs. 1.7%). For every extra pack per day smoked at home, the odds of a child having NAFLD increased 1.8 times (AOR 1.8, 95% CI 1.2, 2.8), and any exposure increased a child's odds of NAFLD four-fold (AOR 4.0, 95% CI 1.02, 15.8).

CONCLUSION

We found an association of secondhand smoke exposure and NAFLD in children. This may represent an area for future prevention efforts.

Additive effects of nicotine and high-fat diet on hepatocellular apoptosis in mice: involvement of caspase 2 and inducible nitric oxide synthase-mediated intrinsic pathway signaling

Smoking is a major risk factor for diabetes and cardiovascular disease and may contribute to nonalcoholic fatty liver disease (NAFLD). The health risk associated with smoking is exaggerated by obesity and is the leading causes of morbidity and mortality worldwide. We recently demonstrated that combined treatment with nicotine and a high-fat diet (HFD) triggers greater oxidative stress, activates hepatocellular apoptosis, and exacerbates HFD-induced hepatic steatosis. Given that hepatocellular apoptosis plays a pivotal role in the pathogenesis of NAFLD, using this model of exacerbated hepatic steatosis, we elucidated the signal transduction pathways involved in HFD plus nicotine-induced liver cell death. Adult C57BL6 male mice were fed a normal chow diet or HFD with 60% of calories derived from fat and received twice daily IP injections of 0.75 mg/kg BW of nicotine or saline for 10 weeks. High-resolution light microscopy revealed markedly higher lipid accumulation in hepatocytes from mice received HFD plus nicotine, compared to mice on HFD alone. Addition of nicotine to HFD further resulted in an increase in the incidence of hepatocellular apoptosis and was associated with activation of caspase 2, induction of inducible nitric oxide synthase (iNOS), and perturbation of the BAX/BCL-2 ratio. Together, our data indicate the involvement of caspase 2 and iNOS-mediated apoptotic signaling in nicotine plus HFD-induced hepatocellular apoptosis. Targeting the caspase 2-mediated death pathway may have a protective role in development and progression of NAFLD.

In vitro exposure to copper influences lipid metabolism in hepatocytes from grass carp (Ctenopharyngodon idellus)

In the present study, three different copper (Cu) concentrations (control, 10 and 100 lM, respectively) and three incubation times (24, 48 and 96 h) were chosen to assess in vitro effect of Cu on lipid metabolism in hepatocytes of grass carp Ctenopharyngodon idellus. Increased glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and carnitine palmitoyltransferase I activities were observed in hepatocytes with increasing Cu concentration and exposure duration. Cu decreased mRNA levels of several lipogenic and lipolytic genes at 24 h. However, at 48 h, Cu down-regulated the process of lipogenesis but up-regulated that of lipolysis. The Cudriven up-regulation of lipolytic genes was maintained after 96 h and accompanied by a decreased intracellular triglyceride accumulation, while no effect on lipogenic genes was shown. Thus, 96-h Cu exposure induced lipid depletion, possibly due to the upregulation of lipolysis. Although in this process, lipogenesis might be up-regulated, it was not enough to compensate lipid consumption. Our study represents the first approach to concentration- and time-dependent in vitro effects of Cu on lipid metabolism of fish hepatocytes and provides new insights into Cu toxicity in fish at both enzymatic and molecular levels.

Cigarette smoke toxins deposited on surfaces: implications for human health

Cigarette smoking remains a significant health threat for smokers and nonsmokers alike. Secondhand smoke (SHS) is intrinsically more toxic than directly inhaled smoke. Recently, a new threat has been discovered - Thirdhand smoke (THS) - the accumulation of SHS on surfaces that ages with time, becoming progressively more toxic. THS is a potential health threat to children, spouses of smokers and workers in environments where smoking is or has been allowed. The goal of this study is to investigate the effects of THS on liver, lung, skin healing, and behavior, using an animal model exposed to THS under conditions that mimic exposure of humans. THS-exposed mice show alterations in multiple organ systems and excrete levels of NNAL (a tobacco-specific carcinogen biomarker) similar to those found in children exposed to SHS (and consequently to THS). In liver, THS leads to increased lipid levels and non-alcoholic fatty liver disease, a precursor to cirrhosis and cancer and a potential contributor to cardiovascular disease. In lung, THS stimulates excess collagen production and high levels of inflammatory cytokines, suggesting propensity for fibrosis with implications for inflammation-induced diseases such as chronic obstructive pulmonary disease and asthma. In wounded skin, healing in THS-exposed mice has many characteristics of the poor healing of surgical incisions observed in human smokers. Lastly, behavioral tests show that THS-exposed mice become hyperactive. The latter data, combined with emerging associated behavioral problems in children exposed to SHS/THS, suggest that, with prolonged exposure, they may be at significant risk for developing more severe neurological disorders. These results provide a basis for studies on the toxic effects of THS in humans and inform potential regulatory policies to prevent involuntary exposure to THS.

Parental smoking during pregnancy and total and abdominal fat distribution in school-age children: the Generation R Study

OBJECTIVE

Fetal smoke exposure may influence growth and body composition later in life. We examined the associations of maternal and paternal smoking during pregnancy with total and abdominal fat distribution in school-age children.

METHODS

We performed a population-based prospective cohort study among 5243 children followed from early pregnancy onward in the Netherlands. Information about parental smoking was obtained by questionnaires during pregnancy. At the median age of 6.0 years (90% range: 5.7-7.4), we measured anthropometrics, total fat and android/gynoid fat ratio by dual-energy X-ray absorptiometry, and preperitoneal and subcutaneous abdominal fat were measured by ultrasound.

RESULTS

The associations of maternal smoking during pregnancy were only present among girls (P-value for sex interaction<0.05). Compared with girls from mothers who did not smoke during pregnancy, those from mothers who smoked during the first trimester only had a higher android/gynoid fat ratio (difference 0.23 (95% confidence interval (CI): 0.09-0.37) s.d. scores (SDS). Girls from mothers who continued smoking throughout pregnancy had a higher body mass index (difference: 0.24 (95% CI: 0.14-0.35) SDS), total fat mass (difference: 0.23 (95% CI: 0.14-0.33) SDS), android/gynoid fat ratio (difference: 0.34 (95% CI: 0.22-0.46) SDS), subcutaneous abdominal fat (difference: 0.22 (95% CI: 0.11-0.33) SDS) and preperitoneal abdominal fat (difference: 0.20 (95% CI: 0.08-0.31) SDS). Similar associations with body fat distribution outcomes were observed for paternal smoking during pregnancy. Both continued maternal and paternal smoking during pregnancy may be associated with an increased risk of childhood overweight. The corresponding odds ratios were 1.19 (95% CI: 0.98-1.46) and 1.32 (1.10-1.58), respectively.

CONCLUSIONS

Maternal and paternal smoking during pregnancy are associated with an adverse body and abdominal fat distribution and increased risk of overweight in children. Similar effects of maternal and paternal smoking suggest that direct intrauterine mechanisms and common family-based lifestyle-related factors explain the associations.

Time-resolved analysis of the emission of sidestream smoke (SSS) from cigarettes during smoking by photo ionisation/time-of-flight mass spectrometry (PI-TOFMS): towards a better description of environmental tobacco smoke

In this study, the chemical composition of sidestream smoke (SSS) emissions of cigarettes are characterised using a laser-based single-photon ionisation time-of-flight mass spectrometer. SSS is generated from various cigarette types (2R4F research cigarette; Burley, Oriental and Virginia single-tobacco-type cigarettes) smoked on a single-port smoking machine and collected using a so-called fishtail chimney device. Using this setup, a puff-resolved quantification of several SSS components was performed. Investigations of the dynamics of SSS emissions show that concentration profiles of various substances can be categorised into several groups, either depending on the occurrence of a puff or uninfluenced by the changes in the burning zone during puffing. The SSS emissions occurring directly after a puff strongly resemble the composition of mainstream smoke (MSS). In the smouldering phase, clear differences between MSS and SSS are observed. The changed chemical profiles of SSS and MSS might be also of importance on environmental tobacco smoke which is largely determined by SSS. Additionally, the chemical composition of the SSS is strongly affected by the tobacco type. Hence, the higher nitrogen content of Burley tobacco leads to the detection of increased amounts of nitrogen-containing substances in SSS.

Exposure to ambient air particulate matter and non-alcoholic fatty liver disease

The present study was designed to alert the public opinion and policy makers on the supposed enhancing effects of exposure to ambient air particulate matter with aerodynamic diameters < 2.5 mm (PM_2.5) on non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease in Western countries. For far too long literature data have been fixated on pulmonary diseases and/or cardiovascular disease, as consequence of particulate exposure, ignoring the link between the explosion of obesity with related syndromes such as NAFLD and air pollution, the worst characteristics of nowadays civilization. In order to delineate a clear picture of this major health problem, further studies should investigate whether and at what extent cigarette smoking and exposure to ambient air PM_2.5 impact the natural history of patients with obesity-related NAFLD, i.e., development of non alcoholic steatohepatitis, disease characterized by a worse prognosis due its progression towards fibrosis and hepatocarcinoma.

Interactive effects of smoking and glutathione S-transferase polymorphisms on the development of non-alcoholic fatty liver disease

Glutathione S-transferases (GSTs) protect cells against exogenous and endogenous oxidative stress. GST polymorphisms are associated with the development of cardiovascular disease (CVD) and diabetes mellitus (DM), especially in current-smokers. Non-alcoholic fatty liver disease (NAFLD) is a predictor of future CVD or DM, because oxidative stress contributes to their pathogenesis. This study investigated whether the combination of smoking status and GST genotypes could affect the risk for NAFLD. A cross-sectional analysis was conducted among 713 Japanese participants (458 males and 255 females) during a health screening program. The GSTM1 null, GSTT1 null, GSTP1 A/B or B/B and GSTA1 A/B or B/B genotypes were determined and deemed to be high-risk genotypes. The prevalence of NAFLD was 18.7%. Among never-smokers, carriers of one, and those of two or more high-risk GSTM1, GSTP1 or GSTA1 genotypes were at a higher risk for NAFLD than those who were not carriers [odds ratio (95% confidence interval): 2.6 (1.1-5.9) and 3.3 (1.3-8.1), respectively], and the risk was further increased among current-smokers [4.6 (1.6-13.0) and 5.4 (1.2-23.7), respectively]. This is the first report to show that the combination of current-smoking and harboring high-risk GSTM1, GSTP1 and/or GSTA1 genotypes is interactively associated with the risk of NAFLD.

Therapeutic approaches to non-alcoholic fatty liver disease: past achievements and future challenges

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver injury and mortality in Western countries and China. However, as to date, there is no direct and effective therapy for this disease. The aim of this review is to analyze the key progress and challenges of main current therapeutic approaches in NAFLD.

DATA SOURCE

We carried out a PubMed search of English-language articles relevant to NAFLD therapy.

RESULTS

There are two major therapeutic strategies for NAFLD treatment: (1) lifestyle interventions (including weight reduction, dietary modification and physical exercise) and (2) pharmaceutical therapies. Lifestyle interventions, particularly chronic and moderate intensity exercise, are the most effective and recognized clinical therapies for NAFLD. For pharmaceutical therapies, although their effects and mechanisms have been extensively investigated in laboratory studies, they still need further tests and investigations in clinical human trials.

CONCLUSION

Future advancement of NAFLD therapy should focus on the mechanistic studies on cell based and animal models and human clinical trials of exercise, as well as the combination of lifestyle intervention and pharmaceutical therapy specifically targeting main signaling pathways related to lipid metabolism, oxidative stress and inflammation.

Active smoking, passive smoking, and risk of nonalcoholic fatty liver disease (NAFLD): a population-based study in China

BACKGROUND

The effect of active smoking on development of nonalcoholic fatty liver disease (NAFLD) is controversial, and there are limited clinical data on the relationship between passive smoking and NAFLD. We investigated whether active and passive smoking are associated with NAFLD.

METHODS

A total of 8580 subjects (2691 men) aged 40 years or older participated in a community-based survey in Shanghai, China. Information on active and passive smoking was collected using a validated questionnaire. NAFLD was diagnosed by abdominal B-mode ultrasound testing and serum liver enzymes.

RESULTS

NAFLD prevalence was 29.4% in never smokers, 34.2% in former smokers, 27.8% in light smokers (<20 cigarettes/day), 30.8% in moderate smokers (20-39 cigarettes/day), and 43.5% in heavy smokers (≥40 cigarettes/day). Fully adjusted logistic regression analyses revealed that, as compared with never smoking, former and heavy smoking were associated with increased risk of prevalent NAFLD, with odds ratios of 1.45 (95% CI 1.05-2.00) and 2.29 (95% CI 1.30-4.03), respectively. Active smoking and body mass index (BMI) had a synergistic effect on the risk of prevalent NAFLD; the combination of these risk factors was associated with the highest observed odds ratio for NAFLD: 8.58. In never-smoking women, passive smoking during both childhood and adulthood was associated with a 25% increase in the risk of prevalent NAFLD (OR = 1.25, 95% CI 1.05-1.50) as compared with no passive smoking.

CONCLUSIONS

Passive smoking and heavy active smoking are associated with prevalent NAFLD in middle-aged and elderly Chinese. Active smoking and BMI have a synergistic effect on prevalent NAFLD.

Liver and diabetes. A vicious circle

The complex and bi-directional relationship linking the liver and diabetes has recently gained intense new interest. This critical review of the published work aims to highlight the most recent basic and clinical data underlying the development of type 2 diabetes, in those with non-alcoholic fatty liver disease. Moreover, the potentially detrimental effects of type 2 diabetes in liver injury are also discussed in each of the two sections of the present paper. Fatty liver and diabetes share insulin resistance as their chief pathogenic determinant. The roles of the hypothalamus, the intestinal microbiome, white adipose tissue and inflammation are discussed in detail. Molecular insights into hepatocyte insulin resistance as the initiator of systemic insulin resistance are also presented with full coverage of the danger of fatty acids. Lipotoxicity, apoptosis, lipoautophagy, endoplasmic reticular stress response and recent developments in genetics are discussed. Closing the circle, special emphasis is given to biochemical pathways and clinical evidence supporting the role of type 2 diabetes as a risk factor for the development of progressive liver disease, including non-alcoholic steatohepatitis, cirrhosis and primary liver cancer. In conclusion, data support non-alcoholic fatty liver disease as a risk factor for the development of type 2 diabetes which is, in turn, a major contributor to progressive liver disease. This pathway leading from fatty liver to type 2 diabetes and back from the latter to the progressive liver disease is a vicious circle.

Smoking in diabetic nephropathy: sparks in the fuel tank?

Diabetic nephropathy is associated with high morbidity and mortality and the prevalence of this disease is continuously increasing worldwide. Long-term diabetes increases the likelihood of developing secondary complications like nephropathy, the most common cause of end stage renal disease. Usually, other factors like hypertension, alcoholism and smoking also partly contribute to the progression of diabetic nephropathy. Among this, cigarette smoking in diabetes has been repeatedly confirmed as an independent risk factor for the onset and progression of diabetic nephropathy. Various studies suggest that smoking is a major fuel in the development of high oxidative stress and subsequently hyperlipidemia, accumulation of advanced glycation end products, activation of the renin angiotensin system and Rho-kinase, which are observed to play a pathogenic role in the progression of diabetic nephropathy. Furthermore, cigarette smoking in diabetic patients with vascular complications produces a variety of pathological changes in the kidney, such as thickening of the glomerular basement membrane and mesangial expansion with progression in glomerulosclerosis and interstitial fibrosis, which ultimately results in end stage renal failure. Strong associations are consistently found between chronic cigarette smoking and diabetic microvascular complications. A diverse group of studies unveil potential mechanisms that may explain the role of cigarette smoking in the progression of diabetic nephropathy. Tremendous efforts are being made to control smoking mediated progression of diabetic nephropathy, but no promising therapy is yet available. The present review critically discusses the possible detrimental role of chronic cigarette smoking in the progression of diabetic nephropathy and various possible pharmacological interventions to attenuate the exacerbation of diabetic nephropathy.

Prevalence and risk factors of non-alcoholic fatty liver disease in the elderly: results from the Rotterdam study

BACKGROUND & AIMS

The prevalence of non-alcoholic fatty liver disease (NAFLD) appears to increase with age. However, limited data are available concerning the prevalence of NAFLD in the elderly. Our aim was to determine the prevalence and risk factors of NAFLD in an elderly population.

METHODS

This study was based on participants in the population-based Rotterdam Study. Each participant was interviewed and had a clinical examination at the research center, including a fasting blood collection, liver ultrasonography, and anthropometric assessment. Ordinal and logistic regression analysis was used to assess associations between covariables and (severity of) NAFLD.

RESULTS

Data from 2811 participants (mean age 76.4 ± 6.0 years) were analyzed. The prevalence of NAFLD was 35.1%. The prevalence of NAFLD decreased with advancing age (p<0.001). In logistic regression analysis, age (OR 0.97; 95% CI 0.95-0.99; p<0.001), total physical activity level (OR 0.98, 95% CI 0.96-0.99; p=0.005), pack years of smoking (OR 1.01, 95% CI 1.00-1.01; p=0.02), waist circumference >88 cm for women and > 102 cm for men (OR 4.89; CI 4.00-5.96; p<0.001), fasting glucose ≥ 100 mg/dl or drug treatment for elevated blood glucose (OR 2.11, 95% CI 1.72-2.59; p<0.001), blood pressure ≥ 130/85 mmHg or drug treatment for elevated blood pressure (OR 1.80, 95% CI 1.08-3.01; p=0.03), and triglycerides ≥ 150 mg/dl or treatment with serum lipid reducing agents (OR 1.56, 95% CI 1.28-1.91; p<0.001) were associated with NAFLD.

CONCLUSIONS

NAFLD is common in the elderly, although the prevalence decreases with advancing age. Further studies are warranted exploring potential factors contributing to this apparent positive selection effect in the elderly.

Additive effects of nicotine and high-fat diet on hepatic steatosis in male mice

Smoking is a major risk factor for diabetes and cardiovascular disease and may contribute to nonalcoholic fatty liver disease. We hypothesize that in the presence of nicotine, high-fat diet (HFD) causes more severe hepatic steatosis in obese mice. Adult C57BL6 male mice were fed a normal chow diet or HFD and received twice daily injections of nicotine (0.75 mg/kg body weight, ip) or saline for 10 wk. Light microscopic image analysis revealed significantly higher lipid accumulation in livers from mice on HFD plus nicotine (190 ± 19 μm(2)), compared with mice on HFD alone (28 ± 1.2 μm(2)). A significant reduction in the percent volume of endoplasmic reticulum (67.8%) and glycogen (49.2%) was also noted in hepatocytes from mice on HFD plus nicotine, compared with mice on HFD alone. The additive effects of nicotine on the severity of HFD-induced hepatic steatosis was associated with significantly greater oxidative stress, increased hepatic triglyceride levels, higher incidence of hepatocellular apoptosis, inactivation (dephosphorylation) of AMP-activated protein kinase, and activation of its downstream target acetyl-coenzyme A-carboxylase. Treatment with acipimox, an inhibitor of lipolysis, significantly reduced nicotine plus HFD-induced hepatic lipid accumulation. We conclude that: 1) greater oxidative stress coupled with inactivation of AMP-activated protein kinase mediate the additive effects of nicotine and HFD on hepatic steatosis in obese mice and 2) increased lipolysis is an important contributor to hepatic steatosis. We surmise that nicotine exposure is likely to exacerbate the metabolic abnormalities induced by high-fat intake in obese patients.

Effect of co-exposure to nickel and particulate matter on insulin resistance and mitochondrial dysfunction in a mouse model

Background

It has been well recognized that toxicity of fine ambient air particulate matter (PM_2.5) may depend on its chemical constituents, including components such as soluble metals that may theoretically exert distinctive effects. We have recently demonstrated an important effect of PM_2.5 on metabolic function. Since transition metals, such as nickel (Ni), represent an important component of exposure in certain environments, and may significantly influence the toxicity of inhalational exposure, we investigated the effects of Ni as a variable component of ambient PM_2.5 exposure.

Methods

Male ApoE knockout mice were exposed to filtered air (FA), fine-sized nickel sulfate particles alone (Ni) at 0.44 μg/m³, concentrated ambient air PM_2.5 (CAPs) at a mean of 70 μg/m³, or CAPs+Ni in Tuxedo, NY, 6 hours/day, 5 days/week, for 3 months.

Results

Exposure to Ni, irrespective of co-exposure to CAPs, resulted in body weight gain, while exposure to CAPs+Ni significantly enhanced fasting glucose and worsened insulin resistance measures (HOMA-IR), when compared with exposure to CAPs alone. CAPs+Ni exposure induced a significant decrease in phosphorylation of AMP-activated protein kinase (AMPK) α. Exposure to Ni or CAPs+Ni significantly induced microcirculatory dysfunction and increased monocytic cell infiltration into lung and adipose, and decreased uncoupling protein 1 expression at gene and protein levels and several brown adipocyte-specific genes in adipose tissue.

Conclusions

Ni exposure has effects on metabolic and inflammatory parameters that are comparable to that of CAPs. Additionally, Ni synergistically exacerbates CAPs-induced adverse effects on some of, but not all of, these parameters, that may be mediated via the AMPK signaling pathway. These findings have important implications for inhaled transition metal toxicity that may exert synergistic effects with other PM_2.5 components.

Second-hand tobacco smoke and children

Cigarette smoke contains harmful chemicals with hazardous adverse effects on almost every organ in the body of smokers as well as of nonsmokers exposed to environmental tobacco smoke (ETS). There has been increasing interest in the effects of passive smoking on the health of children. In order to detect the magnitude of passive smoking in children, parental questionnaires, measuring nicotine and cotinine body levels, and evaluating expired carbon monoxide (CO) concentrations, have been used. Passive smoking causes respiratory illness, asthma, poor growth, neurological disorders, and coronary heart diseases. Herein, we focused on the deleterious influences of passive smoking on immunity and liver. Besides, its effects on the concentrations of various biomarker levels related to the oxidant/antioxidant status were considered. Understanding these effects may help clinicians to counsel parents on smoking cessation and smoke exposure elimination. It may also help to develop interventions to improve the health of children. This review potentially demonstrated some nutraceuticals with a promising role in the prevention of smoking-related diseases.

Azuki bean polyphenols intake during lactation upregulate AMPK in male rat offspring exposed to fetal malnutrition

OBJECTIVE

Fetal malnutrition is an early-life inducer of dyslipidemia and glucose intolerance. The aim of this study was to examine whether maternal azuki bean (Vigna angularis) polyphenol (AP) intake during lactation affects the adenosine monophosphate-activated protein kinase (AMPK) pathway and lipid metabolism in offspring exposed to fetal malnutrition.

METHODS

Pregnant Wistar rats were divided into three groups: a control diet offered during gestation and lactation (CC), a low-protein diet during gestation and a control diet during lactation (LPC); and a low-protein diet during gestation and a 1.0% AP-containing control diet during lactation (LPAP). Male pups were randomly selected for the study; half the pups were sacrificed at 3 wk of age and the other half were fed a standard diet and sacrificed at 23 wk. Hepatic triacylglycerol levels, phosphorylation levels of AMPK and acetyl-coenzyme A carboxylase (ACC), and mRNA levels of sterol regulatory element-binding protein-1c (SREBP-1c) were evaluated.

RESULTS

Significant decreases in body weights and hepatic triacylglycerol levels were found in the LPAP compared with the LPC group. Plasma adiponectin levels in the LPAP group were higher than those in the LPC group. AMPK phosphorylation was upregulated in the livers and skeletal muscles in young and adult LPAP compared with LPC rats. ACC phosphorylation was upregulated in skeletal muscles of LPAP rats. SREBP-1c mRNA expression was decreased in the livers of LPAP rats.

CONCLUSION

Our results suggest that maternal AP intake during lactation upregulates AMPK phosphorylation not only in young but also in adult offspring exposed to fetal malnutrition and may lead to decreased hepatic lipid accumulation by ACC phosphorylation and downregulation of SREBP-1c expression.

Altered adipocyte progenitor population and adipose-related gene profile in adipose tissue by long-term high-fat diet in mice

AIMS

High-fat diet (HFD) is associated with adipose inflammation, which contributes to key components of metabolic abnormalities. The expanded adipose tissue mass associated with obesity is the result of hyperplasia and hypertrophy of adipocytes. In this study, we investigated the effects of long-term HFD on adipocyte progenitor cell (APC) population and adipose-specific gene profiles in both white and brown adipose, and the role of perivascular adipose in the alteration of vascular function in response to HFD.

MAIN METHODS

Male C57BL/6 mice were fed a standard normal diet (ND) or HFD for about 8 months. Glucose metabolism was assessed by an intraperitoneal glucose tolerance test. APC population and adipose-related gene profile were evaluated, and vascular function was measured in the presence or absence of perivascular adipose. Adiponectin and AMPK activity were also investigated.

KEY FINDINGS

HFD induced insulin resistance and glucose intolerance, and resulted in a decrease in APC population in brown, but not in white adipose tissue, when compared with animals fed a ND, with differential alterations of white and brown adipocyte-specific gene expression in brown and white adipose. Additionally, HFD led to altered vascular function in arteries in the presence of perivascular adipose tissue, which is associated with increased superoxide production. Adiponectin and AMPK activity were significantly decreased in response to long-term HFD.

SIGNIFICANCE

These findings suggest that long-term high-fat intake differentially alters adipocyte progenitor population and adipose-related gene expression in adipose tissue, and adiponectin-AMPK signaling might be involved. In addition, HFD induces changes in perivascular adipose-mediated vascular function.

Resveratrol helps recovery from fatty liver and protects against hepatocellular carcinoma induced by hepatitis B virus X protein in a mouse model

Resveratrol is a natural polyphenol that has beneficial effects across species and various disease models. Here, we investigate whether resveratrol is effective against hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) using HBV X protein (HBx) transgenic mice. We found that resveratrol (30 mg/kg/d) has a therapeutic effect on HBx-induced fatty liver and the early stages of liver damage. Resveratrol decreased intracellular reactive oxygen species and transiently stimulated hepatocyte proliferation. Interestingly, resveratrol inhibited LXRα and downregulated the expression of the lipogenic genes, Srebp1-c and PPARγ. The decrease in Srebp1-c seems to further downregulate the expression of its target genes, Acc and Fas. In addition, resveratrol stimulated the activity of Ampk and SirT1. Thus, resveratrol has a pleiotropic effect on HBx transgenic mice in terms of the downregulation of lipogenesis, the promotion of transient liver regeneration, and the stimulation of antioxidant activity. Furthermore, at the later precancerous stages, resveratrol delayed HBx-mediated hepatocarcinogenesis and reduced HCC incidence from 80% to 15%, a 5.3-fold reduction. Resveratrol should be considered as a potential chemopreventive agent for HBV-associated HCC.

Effect of nicotine on body composition in mice

Nicotine induces weight loss in both humans and rodents consuming a regular diet; however, the effect of nicotine on body weight and fat composition in rodents consuming a high-fat diet (HFD) has not been well studied. Thus, this study examined the effect of nicotine vs saline on body weight and fat composition in mice fed with either an HFD (62% of kcal from fat) or a standard normal chow diet (NCD) for 7 weeks. Nicotine dose dependently reduced body weight gain in mice that consumed both diets, but this effect was significantly greater in mice on the HFD. Caloric intake was decreased in nicotine-treated mice. Estimates of energy intake suggested that decreased caloric intake accounted for all the reduced weight gain in mice on an NCD and 66% of the reduced weight gain on an HFD. Computed tomography analysis for fat distribution demonstrated that nicotine was effective in reducing abdominal fat in mice that consumed the HFD, with nicotine treatment leading to lower visceral fat. The effect of nicotine on weight loss in mice on an HFD was completely blocked by mecamylamine, a nonselective nicotinic acetylcholine receptor (nAChR) antagonist, but only partially blocked by the α4β2 nAChR partial agonist/antagonist, varenicline. We conclude that nicotine is effective in preventing HFD-induced weight gain and abdominal fat accumulation.

PPARG gene Pro12Ala variant contributes to the development of non-alcoholic fatty liver in middle-aged and older Chinese population

Oxidative stress has been suggested to contribute to the development of non-alcoholic fatty liver disease (NAFLD). Peroxisome proliferator-activated receptor gamma (PPAR-γ) heterozygous mice and Pro12Ala (C/G) polymorphism in PPARG exhibited increased resistance to oxidative stress. Smoking increases the production of reactive oxygen species, which could accelerates oxidative stress under overnutrition. To explore whether the C/G polymorphism, alone or in combination with smoking, may promote the development of non-alcoholic fatty liver, a case-control study was performed in 903 Chinese subjects. Among the study population, 436 patients with B-mode ultrasound-proven NAFLD (318 with steatosis hepatis I°, 90 with steatosis hepatis II° and 28 with steatosis hepatis III°) and 467 controls were genotyped by using TaqMan allelic discrimination assays. After adjusting for confounders, the C/C genotype significantly associated with NAFLD (OR=1.87, 95%CI 1.13-2.85, p=0.009); smoking was also an independent risk factor for NAFLD (OR=1.69, 95%CI 1.18-2.43, p=0.025). In addition, we found possible synergistic effects, the higher risk group (smokers with the C/C genotype) showed 3.75 times higher risk of NAFLD than the low-risk group (non-smokers with C/G genotype) in a multiple logistic analysis after adjusting for the confounders (p<0.001), but no departure from additivity was found. Our results indicated that the C/C genotype and smoking were significant independent risk factors for NAFLD. The possible synergistic effects of genotype and smoking may promote the development of NAFLD by aggravating oxidative stress, which supports the hypothesis that oxidative stress contributes to the development of NAFLD.

Role of the AMPK/SREBP-1 pathway in the development of orotic acid-induced fatty liver

Orotic acid (OA), an intermediate in pyrimidine metabolism, has been used for a variety of purposes, such as dietary supplements. Although it is well documented that OA induces fatty liver in a species-specific manner, the precise molecular mechanisms remain unclear. The present study investigated the role of the adenosine monophosphate-activated protein kinase (AMPK)-sterol regulatory element-binding protein-1 (SREBP-1) pathway in the OA-induced fatty liver. Treatment with OA suppressed the phosphorylation of AMPK via proteasomal degradation of upstream kinase LKB1 and induced activation of SREBP-1 in both human hepatoma cell lines and primary rat hepatocytes. OA-induced SREBP-1 transcriptional activity was suppressed by cotreatment with aminoimidazole carboxamide ribonucleotide (AICAR) or metformin, or by overexpression of constitutively active AMPK (CA-AMPK) in the human hepatoma cell line. Importantly, in vivo data corroborated these results. Feeding 1% OA with diet decreased the phosphorylation of AMPK and increased the maturation of SREBP-1 and the expression of SREBP-responsive genes in the rat liver. OA-induced lipid accumulation was also completely inhibited by rapamycin. Mouse hepatocytes and mice were resistant to OA-induced lipogenesis because of little if any response in AMPK and downstream effectors. In conclusion, OA induces hepatic lipogenesis, mediated predominantly by the AMPK/SREBP-1 pathway in rat hepatocytes and human hepatoma cell lines.

Impact of cigarette smoking on onset of nonalcoholic fatty liver disease over a 10-year period

BACKGROUND

Metabolic syndrome, which includes obesity, hyperglycemia, dyslipidemia, and hypertension, is a major risk factor for the development of nonalcoholic fatty liver disease (NAFLD). Cigarette smoking is a well-known risk factor for metabolic syndrome, but the epidemiological impact of cigarette smoking on development of NAFLD is unclear.

METHODS

In this retrospective study, 2,029 subjects underwent a complete medical health checkup in 1998 and again in 2008. Those who were positive for hepatitis B surface antigen or hepatitis C virus antibody, or had an alcohol intake of > 20 g/day as assessed by questionnaire, were excluded. Fatty liver was diagnosed by abdominal ultrasonography. Independent risk factors associated with the development of NAFLD were determined by multiple logistic regression analysis. Smoking status was expressed using the Brinkman index (BI), which was calculated as the number of cigarettes smoked per day multiplied by the number of years of smoking.

RESULTS

Of 1,560 subjects without NAFLD in 1998, 266 (17.1%) were newly diagnosed with NAFLD in 2008. Multiple logistic analysis identified age [adjusted odds ratio (AOR) 0.95, 95% confidence interval (95% CI) 0.94-0.97], male sex (AOR 1.46, 95% CI 1.01-2.10), body mass index ≥ 25 (AOR 3.08, 95% CI 2.20-4.32), dyslipidemia (AOR 1.79, 95% CI 1.25-2.58) and cigarette smoking (AOR 1.91, 95% CI 1.34-2.72) as risk factors associated with the development of NAFLD. Smoking status at baseline was also associated with the development of NAFLD (BI 1-399: AOR 1.77, 95% CI 1.02-3.07, BI ≥ 400: AOR 2.04, 95% CI 1.37-3.03).

CONCLUSION

Cigarette smoking is an independent risk factor for onset of NAFLD.

Smoking and severity of hepatic fibrosis in nonalcoholic fatty liver disease

BACKGROUND & AIMS

Although many predictors of disease severity of nonalcoholic fatty liver disease (NAFLD) have been proposed, studies of the potential effects of specific environmental exposures on human NAFLD are lacking. Smoking increases insulin resistance. Given the pathophysiological role of insulin resistance in NAFLD, characterization of the influence of smoking in NAFLD is warranted. The aim of this paper was to study the potential association between cigarette smoking and advanced fibrosis in NAFLD.

METHODS

All adults enrolled in the NASH CRN studies, between October 2004 and February 2008, who had liver biopsies, were included (n=1091). Advanced fibrosis was defined as stages 3-4. Analyses were performed.

RESULTS

Significant bivariate associations were demonstrated between advanced fibrosis and age, gender, ethnicity, diabetes, and smoking history. History of smoking ≥ 10 pack-years was more common (p <0.0001) among patients with advanced fibrosis. Multivariate analysis demonstrated an association between smoking history of ≥ 10 pack-years and advanced fibrosis (OR=1.63). Among non-diabetics, history of ≥ 10 pack-years was associated with an OR of 2.48 for advanced fibrosis. High frequencies of advanced fibrosis were observed among diabetics (with or without ≥ 10 pack-years history) and non-diabetics with ≥ 10 pack-years history as compared to non-diabetics without significant smoking history.

CONCLUSIONS

Smoking history was associated with advanced liver fibrosis in this large multicenter cohort of NAFLD patients. The results indicate that smoking may enhance the progression of NAFLD partly through its effect on insulin resistance. Our results are consistent with recent animal studies suggesting that cigarette smoke may aggravate fatty liver. To our knowledge, this is the first study to show that cigarette smoking is associated with increased fibrosis severity in human NALFD, suggesting it may accelerate disease progression. These results may support a formal recommendation of smoking cessation in patients with NAFLD.

High prevalence of nonalcoholic fatty liver in patients with idiopathic venous thromboembolism

AIM: To assess the prevalence of nonalcoholic fatty liver disease (NAFLD) in patients with idiopathic venous thromboembolism (VTE).

METHODS: In a case-control study, after excluding subjects with well-consolidated risk factors for VTE, idiopathic VTE was documented in 138 consecutive patients who were referred to our department. Two hundred and seventy-six healthy sex/age/body-mass-index-matched subjects, without any clinical/instrumental evidence of VTE, served as controls. All underwent a clinical/laboratory/ultrasound assessment for the presence of metabolic syndrome and NAFLD.

RESULTS: NAFLD was detected in 112/138 cases (81%) and in 84/276 controls (30%) [risk ratio: 2.7, 95% confidence interval (CI): 2.2-3.2, P < 0.0001]. Metabolic syndrome and smoking habit were more prevalent in patients with idiopathic VTE. The high prevalence of NAFLD in VTE was also confirmed after adjustment for inherited thrombophilia. NAFLD was clearly predicted by VTE (odds ratio: 1.8, 95% CI: 1.2-2.7, P < 0.0001).

CONCLUSION: NAFLD was independently associated with idiopathic VTE.

Nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD), the most common liver disorder in the Western world, is a clinico-histopathological entity in which excessive triglyceride accumulation in the liver occurs. Non-alcoholic steatohepatitis (NASH) represents the necroinflammatory form, which can lead to advanced liver fibrosis, cirrhosis, and hepatocellular carcinoma. The pathogenesis of NAFLD/NASH is complex but increased visceral adiposity plus insulin resistance with increased free fatty acids release play an initial key role for the onset and perpetuation of liver steatosis. Further events in the liver include oxidative stress and lipid peroxidation, decreased antioxidant defences, early mitochondrial dysfunction, iron accumulation, unbalance of adipose-derived adipokines with a chronic proinflammatory status, and gut-derived microbial adducts. New gene polymorphisms increasing the risk of fatty liver, namely APOC3 and PNPLA3, have been lately identified allowing further insights into the pathogenesis of this condition. In our review pathophysiological, genetic, and essential diagnostic and therapeutic aspects of NAFLD are examined with future trends in this field highlighted.

Hyperandrogenemia is independently associated with elevated alanine aminotransferase activity in young women with polycystic ovary syndrome

CONTEXT

Women with polycystic ovary syndrome (PCOS) have been implicated to have higher levels of alanine aminotransferase (ALT) because of the high prevalence of obesity.

OBJECTIVE

Our aim was to investigate the relationship between elevated ALT and aspartate aminotransferase (AST) activity and characteristic hyperandrogenism in women with PCOS.

DESIGN AND SETTING

We conducted a cross-sectional case-control study in a reproductive endocrinology clinic and voluntary annual medical health check-up program of the health management center in a tertiary medical center.

PATIENTS

A total of 279 women with PCOS and 279 age-frequency-matched healthy women were studied.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURES

All subjects underwent anthropometric measurement, clinical history recorded by questionnaires, and biochemical tests after an overnight fast.

RESULTS

The prevalence of elevated ALT and AST levels was significantly higher in women with PCOS than healthy control subjects. Multivariate regression analysis for women revealed that the presence of PCOS was significantly associated with elevated ALT but not AST after adjustment for age, obesity, and dyslipidemia. The level of androgenicity represented by free androgen index in women with PCOS was significantly related to elevated ALT and AST levels in multivariate regression models. Women with PCOS who had the highest quartile of free androgen index level had the highest risk of elevated ALT level after adjustment for age, obesity, insulin resistance, and dyslipidemia.

CONCLUSIONS

The risk of elevated ALT level is significantly higher in women with PCOS than those without, independent of obesity. The elevated ALT levels in women with PCOS were associated with the increased androgen levels, independent of obesity, insulin resistance, and dyslipidemia.

An active part of Artemisia sacrorum Ledeb. attenuates hepatic lipid accumulation through activating AMP-activated protein kinase in human HepG2 cells

Artemisia sacrorum Ledeb. (Compositae) (ASL) is a traditional Chinese medicine used to treat different hepatic diseases. However, a hypolipidemic effect of ASL on fatty liver disease has not been reported. Therefore, we investigated whether 95% ethanol eluate (EE), an active part of ASL, would attenuate hepatic lipid accumulation in human HepG2 cells by activating AMP-activated protein kinase (AMPK). Significant decreases in triglyceride levels and increases in AMPK and acetyl-CoA carboxylase (ACC) phosphorylation were observed when the cells were treated with 95% EE. EE down-regulated the lipogenesis gene expression of sterol regulatory element-binding protein 1c (SREBP1c) and its target genes, such as fatty acid synthase (FAS) and stearoyl-CoA desaturase 1 (SCD1), in a time- and dose-dependent manner. In contrast, the lipolytic gene expression of peroxisome proliferator-activated receptor alpha (PPAR-alpha) and CD36 increased in a time- and dose-dependent manner. These effects were abolished by pretreatment with compound C, an AMPK inhibitor. However, there were no differences in the gene expression of SREBP2, low density lipoprotein receptor (LDLR), hydroxymethyl glutaryl CoA reductase (HMG-CoA), or glucose transporter 2 (GLUT2). At the same time, 95% EE significantly increased the gene expression of acyl CoA oxidase (ACOX) in a time- and dose-dependent manner. Thus, AMPK mediated 95% EE induced suppression of SREBP1c and activation of PPAR-alpha respectively. These finding indicate that 95% EE attenuates hepatic lipid accumulation through AMPK activation and may be active in the prevention of serious diseases such as fatty liver, obesity, and type-2 diabetic mellitus.

PARP-1 inhibition does not restore oxidant-mediated reduction in SIRT1 activity

Sirtuin1 (SIRT1) deacetylase and poly(ADP-ribose)-polymerase-1 (PARP-1) respond to environmental cues, and both require NAD(+) cofactor for their enzymatic activities. However, the functional link between environmental/oxidative stress-mediated activation of PARP-1 and SIRT1 through NAD(+) cofactor availability is not known. We investigated whether NAD(+) depletion by PARP-1 activation plays a role in environmental stimuli/oxidant-induced reduction in SIRT1 activity. Both H(2)O(2) and cigarette smoke (CS) decreased intracellular NAD(+) levels in vitro in lung epithelial cells and in vivo in lungs of mice exposed to CS. Pharmacological PARP-1 inhibition prevented oxidant-induced NAD(+) loss and attenuated loss of SIRT1 activity. Oxidants decreased SIRT1 activity in lung epithelial cells; however increasing cellular NAD(+) cofactor levels by PARP-1 inhibition or NAD(+) precursors was unable to restore SIRT1 activity. SIRT1 was found to be carbonylated by CS, which was not reversed by PARP-1 inhibition or selective SIRT1 activator. Overall, these data suggest that environmental/oxidant stress-induced SIRT1 down-regulation and PARP-1 activation are independent events despite both enzymes sharing the same cofactor.