The intertwisted correlations among non-alcoholic fatty liver disease, atherosclerosis, and metabolic syndrome

Impact of Dietary Crude Protein Level on Hepatic Lipid Metabolism in Weaned Female Piglets

Simple Summary

It has been reported that a high crude protein diet could reverse the diet-induced lipid accumulation in the liver of mice and rodents. However, in vivo data supporting a functional role of a high crude protein diet on hepatic lipid metabolism-associated genes and proteins in weaned piglets is not available. In the present study, we aimed to provide a mechanistic insight into alterations in the hepatic lipid lipogenesis, lipolysis, oxidation, and gluconeogenesis in response to different dietary crude protein levels. Our results demonstrated that dietary crude protein could regulate hepatic lipid metabolism through regulating hepatic lipid lipogenesis, lipolysis, oxidation, and gluconeogenesis. The result indicated an important role of dietary crude protein in regulating hepatic lipid metabolism in weaned piglets.

Abstract

Amino acids serve not only as building blocks for proteins, but also as substrates for the synthesis of low-molecular-weight substances involved in hepatic lipid metabolism. In the present study, eighteen weaned female piglets at 35 days of age were fed a corn- and soybean meal-based diet containing 20%, 17%, or 14% crude protein (CP), respectively. We found that 17% or 20% CP administration reduced the triglyceride and cholesterol concentrations, while enhanced high-density lipoprotein cholesterol (HDL-C) concentration in serum. Western blot analysis showed that piglets in the 20% CP group had higher protein abundance of hormone-sensitive triglyceride lipase (HSL) and peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), as compared with other groups. Moreover, the mRNA expression of sterol regulatory element binding transcription factor 1 (SREBPF1), fatty acid synthase (FASN), and stearoyl-CoA desaturase (SCD) were lower in the 17% or 20% CP group, compared with those of the piglets administered with 14% CP. Of note, the mRNA level of acetyl-CoA carboxylase alpha (ACACα) was lower in the 17% CP group, compared with other groups. Additionally, the mRNA level of lipoprotein lipase (LPL), peroxisome proliferator-activated receptor alpha α (PPARα), glucose-6-phosphatase catalytic subunit (G6PC), and phosphoenolpyruvate carboxykinase 1 (PKC1) in the liver of piglets in the 20% CP group were higher than those of the 14% CP group. Collectively, our results demonstrated that dietary CP could regulate hepatic lipid metabolism through altering hepatic lipid lipogenesis, lipolysis, oxidation, and gluconeogenesis.

Higher fructose intake is inversely associated with risk of nonalcoholic fatty liver disease in older Finnish adults

BACKGROUND

High fructose intake has been suggested to be a key factor that induces nonalcoholic fatty liver disease (NAFLD), but the evidence from large epidemiologic studies is lacking.

OBJECTIVE

We examined the cross-sectional association between fructose intake and NAFLD by using the Fatty Liver Index (FLI) and the NAFLD liver fat score.

DESIGN

The Helsinki Birth Cohort Study investigated 2003 Finnish men and women born in 1943-1944 in Helsinki who participated in a clinical health examination in the years 2001-2004. Trained study nurses measured weight, height, and waist circumference, and body mass index was calculated. Laboratory staff drew fasting blood for measurements of triglycerides and γ-glutamyl-transferase. The FLI and the NAFLD liver fat score were calculated on the basis of these measurements. Habitual fructose and other dietary intake over the past year were assessed by using validated and standardized 131-item food-frequency questionnaires. Data were analyzed in a cross-sectional manner by using logistic regression modeling with statistical software.

RESULTS

In a model adjusted for age, sex, and energy intake, participants in the highest fructose intake quartile (range: 29.2-88.0 g/d) had lower risk of NAFLD assessed by using the FLI (OR: 0.56; 95% CI: 0.42, 0.75; P-trend < 0.001) and NAFLD liver fat score (OR: 0.72; 95% CI: 0.53, 0.99; P-trend < 0.001) than that of the lowest intake quartile (range: 2.2-15.2 g/d). This association remained after adjustment for educational attainment, smoking, physical activity, and other dietary variables only for the FLI (OR: 0.68; 95% CI: 0.47, 0.84; P-trend < 0.05).

CONCLUSION

Our cross-sectional results did not support the current hypothesis that high intake of fructose is associated with a higher prevalence of NAFLD as assessed by using the FLI and NAFLD liver fat score.

Comparison of characteristics between nonobese and overweight/obese subjects with nonalcoholic fatty liver disease in a South Indian population

AIMS

This study was designed to compare the characteristics of nonobese and overweight/obese subjects with nonalcoholic fatty liver disease (NAFLD) in an urban South Indian population.

SUBJECTS AND METHODS

The study group comprises 541 subjects drawn from the Chennai Urban Rural Epidemiology Study (CURES), which was carried out on a representative sample of Chennai city in southern India. NAFLD was diagnosed by ultrasonography. Subjects with NAFLD were classified as nonobese (body mass index of ≤22.9 kg/m(2)) and overweight/obese (body mass index of ≥23 kg/m(2)) based on World Health Organization Asia Pacific guidelines. Coronary artery disease (CAD) was assessed by a resting 12-lead electrocardiogram that was Minnesota-coded. Insulin resistance was assessed by using the homeostasis assessment model (HOMA-IR) using the following formula: fasting insulin (μIU/mL)×fasting glucose (mmol/L)/22.5.

RESULTS

In total, 173 of 541 (32%) subjects had NAFLD, of whom 48 (27.7%) had nonobese NAFLD and 125 (72.3%) had overweight/obese NAFLD. Compared with overweight/obese NAFLD patients, fasting blood glucose (104±29 vs. 119±45 mg/dL; P<0.05) and HOMA-IR (2.1±1.8 vs. 2.9±1.8; P<0.001) were lower and high-density lipoprotein cholesterol (43±9 vs. 39±8 mg/dL; P<0.001) was higher among nonobese NAFLD subjects. Multiple logistic regression analysis showed a significant association between nonobese NAFLD and CAD (P=0.013) even after adjusting for age, diabetes, hypercholesterolemia, HOMA-IR, and hypertension.

CONCLUSIONS

This study suggests that even nonobese NAFLD subjects have an association with CAD.

Early growth and non-alcoholic fatty liver disease in adulthood-the NAFLD liver fat score and equation applied on the Helsinki Birth Cohort Study

INTRODUCTION

Prenatal and childhood growth influence the risk of developing the metabolic syndrome and type 2 diabetes. Both conditions are associated with non-alcoholic fatty liver disease (NAFLD). Our aim was to explore the associations between early growth and adult NAFLD.

METHODS

We studied 1587 individuals from the Helsinki Birth Cohort Study (HBCS) born 1934-44 for whom birth, childhood, and adult clinical data were available. NAFLD was defined using the NAFLD liver fat score and equation. The score was converted into a dichotomous variable, with outcomes defined as either a positive or negative score. The equation predicts liver fat percentage.

RESULTS

A positive score was found in 43% of men and 22.5% of women. Several measurements of birth and childhood body size were negatively associated with both NAFLD outcomes after adjustment for adult BMI. Those from the smallest BMI tertile at age 2 who were obese in adulthood had an OR of 18.5 for a positive score compared to those from the same group who were normal weight in adulthood.

CONCLUSIONS

A larger childhood body size was negatively associated with NAFLD outcomes. Individuals who are small during early childhood and obese as adults seem to be at the highest risk of developing NAFLD.

Effect of dietary blueberry pomace on selected metabolic factors associated with high fructose feeding in growing Sprague-Dawley rats

An experiment was conducted to study the protective effect of feeding extruded and unextruded blueberry pomace (BBP) on selected metabolic parameters associated with metabolic syndrome in a model of high fructose (HF)-fed growing Sprague-Dawley rats. Treatments were as follows: (1) control (modified AIN-based diet); (2) HF diet (AIN diet with 58% fructose); (3) HF diet with 1.5% unextruded BBP; (4) HF diet with 1.5% extruded BBP; (5) HF diet with 3% unextruded BBP; and (6) HF diet with 3% extruded BBP. Compared with the control, HF feeding increased fasting plasma insulin and fasting and postprandial plasma triglycerides as well as homeostatic scores of insulin resistance and β-cell function, but not weight gain, diet intake and efficiency, abdominal fat, oral glucose tolerance, and fasting and postprandial plasma glucose, cholesterol, and leptin levels. Inclusion of unextruded or extruded BBP was effective in minimizing or ameliorating the fructose-induced metabolic anomalies, except postprandial plasma triglycerides, especially at 3% of the diet. In addition, unextruded or extruded BBP at 3% of the diet was also able to reduce plasma cholesterol and abdominal fat relative to the HF control, which may impart additional health benefits. Compared with the control, inclusion of unextruded or extruded BBP at both 1.5% and 3% resulted in lower total fat weight, and animals fed a diet supplemented with 3% unextruded BBP in fasting state or 3% unextruded BBP in fed state had lower leptin levels than the control. This is the first study demonstrating the beneficial effects of feeding blueberry pomace on health.