Relation of hepatic steatosis to atherogenic dyslipidemia

Heat-Killed Enterococcus faecalis Inhibit FL83B Hepatic Lipid Accumulation and High Fat Diet-Induced Fatty Liver Damage in Rats by Activating Lipolysis through the Regulation the AMPK Signaling Pathway

Continuous consumption of high-calorie meals causes lipid accumulation in the liver and liver damage, leading to non-alcoholic fatty liver disease (NAFLD). A case study of the hepatic lipid accumulation model is needed to identify the mechanisms underlying lipid metabolism in the liver. In this study, the prevention mechanism of lipid accumulation in the liver of Enterococcus faecalis 2001 (EF-2001) was extended using FL83B cells (FL83Bs) and high-fat diet (HFD)-induced hepatic steatosis. EF-2001 treatment inhibited the oleic acid (OA) lipid accumulation in FL83B liver cells. Furthermore, we performed lipid reduction analysis to confirm the underlying mechanism of lipolysis. The results showed that EF-2001 downregulated proteins and upregulated AMP-activated protein kinase (AMPK) phosphorylation in the sterol regulatory element-binding protein 1c (SREBP-1c) and AMPK signaling pathways, respectively. The effect of EF-2001 on OA-induced hepatic lipid accumulation in FL83Bs enhanced the phosphorylation of acetyl-CoA carboxylase and reduced the levels of lipid accumulation proteins SREBP-1c and fatty acid synthase. EF-2001 treatment increased the levels of adipose triglyceride lipase and monoacylglycerol during lipase enzyme activation, which, when increased, contributed to increased liver lipolysis. In conclusion, EF-2001 inhibits OA-induced FL83B hepatic lipid accumulation and HFD-induced hepatic steatosis in rats through the AMPK signaling pathway.

Increased Hepatic Lipogenesis Elevates Liver Cholesterol Content

Cardiovascular diseases (CVDs) are the most common cause of death in patients with nonalcoholic fatty liver disease (NAFLD) and dyslipidemia is considered at least partially responsible for the increased CVD risk in NAFLD patients. The aim of the present study is to understand how hepatic de novo lipogenesis influences hepatic cholesterol content as well as its effects on the plasma lipid levels. Hepatic lipogenesis was induced in mice by feeding a fat-free/high-sucrose (FF/HS) diet and the metabolic pathways associated with cholesterol were then analyzed. Both liver triglyceride and cholesterol contents were significantly increased in mice fed an FF/HS diet. Activation of fatty acid synthesis driven by the activation of sterol regulatory element binding protein (SREBP)-1c resulted in the increased liver triglycerides. The augmented cholesterol content in the liver could not be explained by an increased cholesterol synthesis, which was decreased by the FF/HS diet. HMGCoA reductase protein level was decreased in mice fed an FF/HS diet. We found that the liver retained more cholesterol through a reduced excretion of bile acids, a reduced fecal cholesterol excretion, and an increased cholesterol uptake from plasma lipoproteins. Very low-density lipoproteintriglyceride and -cholesterol secretion were increased in mice fed an FF/HS diet, which led to hypertriglyceridemia and hypercholesterolemia in Ldlr-/- mice, a model that exhibits a more human like lipoprotein profile. These findings suggest that dietary cholesterol intake and cholesterol synthesis rates cannot only explain the hypercholesterolemia associated with NAFLD, and that the control of fatty acid synthesis should be considered for the management of dyslipidemia.

Temporal Development of Dyslipidemia and Nonalcoholic Fatty Liver Disease (NAFLD) in Syrian Hamsters Fed a High-Fat, High-Fructose, High-Cholesterol Diet

The use of translationally relevant animal models is essential, also within the field of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Compared to frequently used mouse and rat models, the hamster may provide a higher degree of physiological similarity to humans in terms of lipid profile and lipoprotein metabolism. However, the effects in hamsters after long-term exposure to a NASH diet are not known. Male Syrian hamsters were fed either a high-fat, high-fructose, high-cholesterol diet (NASH diet) or control diets for up to 12 months. Plasma parameters were assessed at two weeks, one, four, eight and 12 months and liver histopathology and biochemistry was characterized after four, eight and 12 months on the experimental diets. After two weeks, hamsters on NASH diet had developed marked dyslipidemia, which persisted for the remainder of the study. Hepatic steatosis was present in NASH-fed hamsters after four months, and hepatic stellate cell activation and fibrosis was observed within four to eight months, respectively, in agreement with progression towards NASH. In summary, we demonstrate that hamsters rapidly develop dyslipidemia when fed a high-fat, high-fructose, high-cholesterol diet. Moreover, within four to eight months, the NASH-diet induced hepatic changes with resemblance to human NAFLD.

Combined use of rosuvastatin and ezetimibe improves hepatic steatosis in patients with dyslipidemia

BACKGROUND AND AIMS

Rosuvastatin plus ezetimibe are beneficial for the management of dyslipidemia. We investigated whether rosuvastatin plus ezetimibe improves hepatic steatosis in patients with dyslipidemia.

METHODS

Between January and August 2018, 114 patients with dyslipidemia treated for 6 months with rosuvastatin plus ezetimibe were analyzed in this retrospective cohort study. The degree of hepatic steatosis was assessed using the hepatic steatosis index (HSI). Hepatic steatosis improvement and presence of fatty liver were defined as a ≥5% reduction in HSI score and HSI ≥36, respectively.

RESULTS

The mean age of the study population (50 males and 64 females) was 57.4 years. At baseline, the mean BMI total cholesterol level, low-density lipoprotein cholesterol level, high-density lipoprotein cholesterol level, triglyceride level, and HSI were 25.1 kg/m, 207.4 mg/dL, 126.1 mg/dL, 52.9 mg/dL, 146.4 mg/dL, and 36.1, respectively. During the 6-month treatment, hepatic steatosis burden was constant (mean HSI = 36.3 and 36.4 at 3 and 6 months, respectively). On multivariate analyses, ultrasonographic fatty liver and HSI ≥36 were selected as independent predictors of hepatic steatosis improvement. However, when 53 (46.5%) patients with fatty liver (HSI ≥ 36) were selected, hepatic steatosis burden was significantly improved (mean HSI = 40.8, 39.3, and 39.7 at baseline, 3 months, and 6 months, respectively).

CONCLUSIONS

The use of rosuvastatin plus ezetimibe for the management of dyslipidemia did not improve hepatic steatosis burden in all patients with dyslipidemia, but it improved hepatic steatosis burden in the subgroup with fatty liver.

Risk factors for cardiovascular disease in patients with non-alcoholic fatty liver disease with polymorbidity

Aim.To study the associations of the frequency and values of parameters of the main risk factors (RF) of cardiovascular diseases (CVD) and the degree of transnosological polymorbidity (PM) in patients with nonalcoholic fatty liver disease (NAFLD).

Material and methods. The analysis of 3667 medical records (men, women) treated in the clinic of Research Institute of Experimental and Clinical Medicine (Novosibirsk) was carried out. Index of polymorbidity was evaluated by the number of nosological forms in accordance with the International Classification of Diseases, 10th revision (ICD-10). The following risk factors were assessed according to clinical and laboratory tests: arterial hypertension, dyslipidemia, hyperglycemia, obesity.

Results.Both among men and women with increasing index of PM there was identified growth of the parameters that determine the main RF: systolic BP, diastolic BP, obesity (both in men and women), atherogenicity index (in women), glucose concentration in the blood serum (in women). Frequency of AH occurrence in persons with a high degree of PM among men was 49%, and among women — 69% higher, compared with persons with a low degree of PM. Among men, there was an increase in the incidence of AH (by 9%) and obesity (by 9%) in individuals with a high degree of PM, compared with individuals with an average degree of PM. Among women, there was an increase in the incidence of AH (by 15%), obesity (by 9%), hyperglycemia (by 11%) in persons with a high degree of PM, compared with individuals with an average degree of PM.

Conclusion.There was established the role of risk factors for cardiovascular diseases, arterial hypertension mainly, in the development of polymorbidity in patients with NAFLD. The findings indicate the need for personified prevention and treatment of such patients with mandatory identification and correction of modifiable CVD RF.

The SCAP/SREBP Pathway: A Mediator of Hepatic Steatosis

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with insulin resistance, obesity, and dyslipidemia. NAFLD encompasses a wide range of states from the simple accumulation of triglycerides in the hepatocytes to serious states accompanied by inflammation and fibrosis in the liver. De novo lipogenesis has been shown to be a significant factor in the development of hepatic steatosis in insulin-resistant states. Sterol regulatory element binding protein-1c (SREBP-1c) is the main transcription factor that mediates the activation of lipogenesis, and SREBP cleavage activating protein (SCAP) is required for the activation of SREBPs. Here, recent animal studies that suggest SCAP as a therapeutic target for hepatic steatosis and hypertriglyceridemia are discussed.

Association between non-alcoholic hepatic steatosis and hyper reactive blood pressure response on the exercise treadmill test

AIMS

Non-alcoholic hepatic steatosis (HS) is associated with hypertension and increased cardiovascular risk. While Blood pressure hyper-reactive response (HRR) during peak exercise indicates an increased risk of incident hypertension and increased cardiovascular risk, no data on the association of non-alcoholic HS and HRR exists. In this study, we have evaluated the association of HS with HRR.

METHODS

We included 13 410 consecutive individuals with a mean age: 42.4  ±  8.9 years, 3561 (26.6%) female with normal resting blood pressure and without a previous diagnosis of hypertension, who underwent symptom limited exercise treadmill test, abdominal ultrasonography and clinical and laboratory evaluation. HS was detected by abdominal ultrasonography. HRR was defined by a peak exercise systolic blood pressure  >220 mmHg and/or elevation of 15 mmHg or more in diastolic blood pressure from rest to peak exercise.

RESULTS

The prevalence of HS was 29.5% (n  =  3956). Overall, 4.6% (n  =  619) of the study population presented a HRR. Subjects with HS had a higher prevalence of HRR (8.1 vs. 3.1%, odds ratio 2.8, 95% CI 2.4-3.3, P  <  0.001). After adjustment for body mass index, waist circumference, fasting plasma glucose and low density lipoprotein cholesterol, HS (odds ratio 1.4, 95% CI 1.1-1.6, P  =  0.002) remained independently associated with HRR. HS was additive to obesity markers in predicting exercise HRR.

CONCLUSIONS

Non-alcoholic HS is independently associated with hyper-reactive exercise blood pressure response.

Blood pressure is associated with the presence and severity of nonalcoholic fatty liver disease across the spectrum of cardiometabolic risk

OBJECTIVES

To determine the relationship between clinically relevant blood pressure (BP) groups and nonalcoholic fatty liver disease (NAFLD) presence and severity especially in the milieu of other metabolic risk factors.

PATIENTS AND METHODS

From a Brazilian cohort of 5362 healthy middle-aged men and women who presented for yearly physical examination and testing, the cross-sectional relationship between BP categories and NAFLD was assessed. BP groups were categorized as normal, prehypertension (PHT), and hypertension (HTN) according to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure classification. NAFLD was ultrasound diagnosed, excluding persons with alcohol consumption more than 20 g/day. NAFLD severity was estimated using the Fibrosis-4 (FIB-4) risk score.

RESULTS

The prevalence of NAFLD was 36.2%. Participants with NAFLD were older (mean 46 vs. 42 years, P < 0.001) and had elevated BMI (mean 29.0 vs. 24.7 kg/m, P < 0.001). The prevalence of NAFLD among persons with normal BP, PHT, and HTN was 16.5, 37.5, and 59.3%, respectively. In multivariate analyses, PHT and HTN were associated with elevated odds of NAFLD (PHT-adjusted odds ratio 1.3, 95% confidence interval 1.1, 1.6; HTN-adjusted odds ratio 1.8, 95% confidence interval 1.4-2.3) compared with normal BP. Among nonobese hypertensive patients, BP control (BP < 140/90 mmHg) was independently associated with 40% lower odds of prevalent NAFLD. Compared with hypertensive patients, both normotensive individuals and prehypertensive patients were more likely to have a low fibrosis risk (FIB-4 ≥ 1.3).

CONCLUSION

Prevalent NAFLD may be seen early in the development of hypertension, even in the absence of other metabolic risk factors. Controlling BP among nonobese hypertensive patients may be beneficial in preventing or limiting NAFLD.

Non-alcoholic fatty liver disease in obese adults: clinical aspects and current management strategies

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder whose prevalence is strongly linked to the current epidemic of obesity in many western countries. The prevalence of NAFLD is two to four times higher in populations with pre-existing metabolic comorbidities than in the general population. The diagnosis of primary NAFLD involves establishing the presence of hepatic steatosis or steatohepatitis by imaging or histology, along with establishing the non-alcoholic nature of the disease process and excluding competing aetiologies for hepatic steatosis. Among the indirect serum biomarkers, the NAFLD fibrosis score can help to identify patients with NAFLD and with higher likelihood of having fibrosis or cirrhosis. A liver biopsy should be considered in NAFLD patients at increased risk for steatohepatitis/advanced fibrosis and in cases where a liver biopsy is necessary to exclude co-existing chronic liver diseases and other aetiologies for hepatic steatosis. The treatment and management recommendations for obesity-associated NAFLD are aimed towards weight reduction. The currently available interventions employed to promote weight loss and improve the metabolic responses in NAFLD include lifestyle modification, pharmacotherapy and bariatric surgery.

Beneficial effects of heat-treated Enterococcus faecalis FK-23 on high-fat diet-induced hepatic steatosis in mice

A high-fat diet (HFD) is one of the causes of hepatic steatosis. We previously demonstrated that Enterococcus faecalis FK-23 (FK-23), a type of lactic acid bacteria, exhibits an anti-obesity effect in mice fed a HFD. In the present study, we examined the effects of FK-23 on HFD-induced hepatic steatosis. Male C57BL/6 mice were divided into four groups and given one of four treatments: standard diet (SD); standard diet supplemented with FK-23 (SD+FK); HFD; or HFD supplemented with FK-23 (HFD+FK). For the administration of FK-23, the drinking water was supplemented with FK-23 at a concentration of 2% (w/w). After 11 weeks, histological findings revealed hepatic steatosis in the liver of HFD-fed mice; however, this effect was attenuated by the administration of FK-23. The expression levels of genes involved in fatty acid oxidation in the liver tissue were significantly reduced in the HFD group compared with the SD group, but FK-23 supplementation tended to up-regulate the expression levels of these genes. Our findings show that the inhibitory effect of FK-23 against hepatic steatosis in HFD-fed mice can be explained by the prevention of fat accumulation in the liver through the modulation of the activities of genes involved in hepatic fatty acid oxidation.

Ethnic and sex differences in fatty liver on cardiac computed tomography: the multi-ethnic study of atherosclerosis

OBJECTIVE

To describe ethnic and sex differences in the prevalence and determinants of fatty liver in a multiethnic cohort.

PATIENTS AND METHODS

We studied participants of the Multi-Ethnic Study of Atherosclerosis who underwent baseline noncontrast cardiac computed tomography between July 17, 2000, and August 29, 2002, and had adequate hepatic and splenic imaging for fatty liver determination (n=4088). Fatty liver was defined as a liver/spleen attenuation ratio of less than 1. We compared the prevalence and severity of fatty liver, in 4 ethnicities (white, Asian, African American, and Hispanic), and the factors associated with fatty liver in each ethnicity, stratifying by obesity and metabolic syndrome. Multivariable ordinal logistic regression was used to determine the effect of cardiometabolic risk factors on the prevalence of fatty liver in different ethnicities.

RESULTS

The prevalence of fatty liver varied significantly by ethnicity (African American, 11%; white, 15%; Asian, 20%; and Hispanic, 27%; P<.001). Although African Americans had the highest prevalence of obesity, a smaller percentage of obese African Americans received a diagnosis of fatty liver than did other ethnicities (African American, 17%; white, 31%; Asian, 37%; and Hispanic 39%; P<.001). Hispanics had the highest prevalence of fatty liver, including the obese and metabolic syndrome population. An increase in insulin resistance predicted a 2-fold increased prevalence of fatty liver in all ethnicities after multivariable adjustment.

CONCLUSION

African Americans have a lower prevalence and Hispanics have a higher prevalence of fatty liver than do other ethnicities. There are distinct ethnic variations in the prevalence of fatty liver even in patients with the metabolic syndrome or obesity, suggesting that genetic factors may play a substantial role in the phenotypic expression of fatty liver.

New peroxisome proliferator-activated receptor agonists: potential treatments for atherogenic dyslipidemia and non-alcoholic fatty liver disease

INTRODUCTION

Novel peroxisome proliferator-activated receptor (PPAR) modulators (selective PPAR modulators [SPPARMs]) and dual PPAR agonists may have an important role in the treatment of cardiometabolic disorders owing to lipid-modifying, insulin-sensitizing and anti-inflammatory effects.

AREAS COVERED

This review summarizes the efficacy of new PPAR agonists and SPPARMs that are under development for the treatment of atherogenic dyslipidemia and non-alcoholic fatty liver disease (NAFLD).

EXPERT OPINION

ABT-335 is a new formulation of fenofibrate that has been approved for concomitant use with statins. K-877, a SPPARM-α with encouraging preliminary results in modulating atherogenic dyslipidemia, and INT131, a SPPARM-γ with predominantly insulin-sensitizing actions, may also have favorable lipid-modifying effects. Although the development of dual PPAR-α/γ agonists (glitazars) and the SPPARM-δ GW501516 has been abandoned because of safety issues, another SPPARM-δ (MBX-8025) and a dual PPAR-α/δ agonist (GFT-505) have shown promising efficacy in decreasing plasma triglyceride and increasing high-density lipoprotein cholesterol concentrations, as well as improving insulin sensitivity and liver function. The beneficial effects of GFT-505 are complemented by preclinical findings that indicate reduction of hepatic fat accumulation, inflammation and fibrosis, making it a promising candidate for the treatment of NAFLD/nonalcoholic steatohepatitis (NASH). Long-term trials are required to test the efficacy and safety of these new PPAR agonists in reducing cardiovascular outcomes and treating NAFLD/NASH.