Paediatric fatty liver disease (FLD) can develop into steatohepatitis, cirrhosis and hepatocellular carcinoma in adulthood. We assessed if early life physical exercise reduced the effects of high-fat (HF) diet-induced steatosis. Male HF-fed rats with access to a running wheel from weaning until day (D)60 (early exercise) or from D67 to D120 (late exercise) were compared with control HF- or chow-fed groups with no wheel. At D63 and D120, liver histopathology (Kleiner score), type I collagen and plasma enzymes were assessed. At D63, early life activity significantly reduced histopathology scores (total, portal inflammation, steatosis, ballooning, but not lobular inflammation or fibrosis) and the number of rats affected. At D120, HF control scores were higher than in chow-fed controls, but the effect of activity was selective: early exercise reduced portal inflammation, steatosis, ballooning and fibrosis, but late activity affected only portal inflammation and ballooning. The chow-fed portal inflammation score was significantly less than all HF groups, but lobular inflammation was lower in the HF control group only. The fibrosis score in the HF early exercise and control chow group were lower than in the late exercise and sedentary HF groups, indicating that early life exercise was more effective than when activity was introduced later in life. Plasma biomarkers showed minor between-group differences. The retained effect on liver histopathology rat at D120 after only early life exposure activity suggests that timing of introduction of exercise is critical in reducing FLD scores and prevalence in children, young adults and possibly into adulthood.

Abstract

Non-alcoholic fatty liver disease (NAFLD) includes a range of disorders from simple steatosis to non-alcoholic steatohepatitis. There is no proven drug treatment for NAFLD, and diet modification is considered part of the main line of treatment for this disease. The aim of this study was to investigate the efficacy of garlic supplementation in NAFLD patients. The effect of garlic powder supplementation on hepatic steatosis, liver enzymes and lipid profile was investigated in NAFLD patients. Ninety NAFLD patients were randomly assigned to take either a garlic powder supplement or a placebo for 12 weeks. The treatment group received four tablets of garlic daily (each tablet contained 400 mg garlic powder). The control group received four tablets of placebo (each placebo contained 400 mg starch). At the end of the study, hepatic steatosis was significantly reduced in the treatment group compared with the control group (P = 0·001). In addition, a significant decrease was seen in the serum concentration of alanine transaminase (P < 0·001), aspartate transaminase (P = 0·002), γ-glutamyltransferase (P = 0·003) as well as total cholesterol (P = 0·009), TAG (P < 0·001), HDL-cholesterol (P < 0·001) and LDL-cholesterol (P = 0·01) in the treatment group compared with the control group. No significant difference was seen between the two groups in serum concentration of alkaline phosphatase. Overall, garlic powder supplementation improved hepatic features and lipid profile among NAFLD patients.

Paediatric non-alcoholic fatty liver disease has increased in parallel with childhood obesity. Dietary habits, particularly products rich in sugars, may influence both hepatic fat and insulin resistance (homeostatic model assessment for insulin resistance (HOMA-IR)). The aim of the study was to examine the association of the consumption of foods and food components, dairy desserts and substitutes (DDS), sugar-sweetened beverages (SSB), as well as total and added sugars, with hepatic fat and HOMA-IR. Dietary intake (two non-consecutive 24 h-recalls), hepatic fat (MRI) and HOMA-IR were assessed in 110 overweight/obese children (10·6 (sd 1·1) years old). Linear regression analyses were used to examine the association of dietary intake with hepatic fat and HOMA-IR adjusted for potential confounders (sex, age, energy intake, maternal educational level, total and abdominal adiposity and sugar intake). The results showed that there was a negative association between cereal intake and hepatic fat (β=–0·197, P<0·05). In contrast, both SSB consumption (β=0·217; P=0·028) and sugar in SSB (β=0·210, P=0·035), but not DDS or sugar in DDS or other dietary components, were positively associated with hepatic fat regardless of potential confounders including total sugar intake. In conclusion, cereal intake might decrease hepatic fat, whereas SSB consumption and its sugar content may increase the likelihood of having hepatic steatosis. Although these observations need to be confirmed using experimental evidence, these results suggest that healthy lifestyle intervention programs are needed to improve dietary habits as well as to increase the awareness of the detrimental effects of SSB consumption early in life.

The incidence of obesity and its metabolic complications are rapidly increasing and become a major public health issue. This trend is associated with an increase in the prevalence of non-alcoholic fatty liver disease (NAFLD), insulin resistance and diabetes. The sequence of events leading to NAFLD progression and mitochondrial dysfunction and their interrelation remains to be elucidated. This study aimed to explore the installation and progression of NAFLD and its association with the liver mitochondrial structure and activity changes in rats fed an obesogenic diet up to 20 weeks. Male Wistar rats were fed either a standard or high-fat–high-fructose (HFHFR) diet and killed on 4, 8, 12, 16 and 20 weeks of diet intake. Rats fed the HFHFR diet developed mildly overweight, associated with increased adipose tissue weight, hepatic steatosis, hyperglycaemia and hyperinsulinaemia after 8 weeks of HFHFR diet. Hepatic steatosis and many biochemical modifications plateaued at 8–12 weeks of HFHFR diet with slight amelioration afterwards. Interestingly, several biochemical and physiological parameters of mitochondrial function, as well as its phospholipid composition, in particular cardiolipin content, were tightly related to hepatic steatosis installation. These results showed once again the interrelation between hepatic steatosis development and mitochondrial activity alterations without being able to say whether the mitochondrial alterations preceded or followed the installation/progression of hepatic steatosis. Because both hepatic steatosis and mitochondrial alterations occurred as early as 4 weeks of diet, future studies should consider these four 1st weeks to reveal the exact interconnection between these major consequences of obesogenic diet intake.

Diet during pregnancy and lactation is a critical factor in relation to the health of dams and their offspring. Currently, control diets used in metabolic imprinting studies differ in composition and type, i.e. semi-purified diets (SD) or chow-based diets (ND). The aim of the present study was to determine whether two widely used control diets, a SD and a ND, that mainly differ in fat content (5·08 and 3·26 %, respectively) and its sources (soyabean oil for the SD and cereals and fish for the ND), fibre (6 and 15 %, respectively), and cholesterol (26 and 69 mg/kg diet, respectively) can influence the lipid metabolism of dams and their offspring. Wistar rats were fed either the SD or the ND during pregnancy and lactation. At weaning, SD-fed dams presented severe hepatic steatosis and increased levels of circulating TAG, NEFA and insulin. Importantly, the offspring presented an altered plasma lipid profile. In contrast, the ND allowed for a normal gestation and lactation process, and did not affect the metabolism of offspring. In parallel, virgin rats fed the SD showed no metabolic alterations. A higher intake of SFA and MUFA and a lower consumption of PUFA observed in SD-fed dams during the lactation period could contribute to explaining the observed effects. In conclusion, two different control diets produced very different outcomes in the lipid metabolism of lactating rats and their offspring. The present results highlight the importance of the assessment of the metabolic state of dams when interpreting the results of metabolic programming studies.

The aim of the present study was to identify molecular mechanisms involved in liver fat and cholesterol accumulation in ovariectomised (Ovx) rats fed with high-cholesterol diets. VLDL assembly and bile acid metabolism were specifically targeted. After being either Ovx or sham-operated, the rats were fed a standard diet or a high-fat diet containing 0, 0·25 or 0·5 % cholesterol for 6 weeks. Although Ovx rats exposed to dietary cholesterol intake accumulated the greatest amount of hepatic fat and cholesterol, plasma cholesterol levels were lower (P< 0·05) in these animals than in the corresponding control rats. Accompanying this observation, ovariectomy and dietary cholesterol intake resulted in a down-regulation (P< 0·05) of the expression of genes associated with VLDL assembly, including microsomal TAG transfer protein, diacylglycerol acyltransferase 2, acyl-CoA:cholesterol acyltransferase 2 and apoB-100 as well as genes associated with bile acid metabolism including farnesoid X receptor and bile salt export pump (P< 0·01). These results indicate that high-fat/high-cholesterol diets and ovariectomy concomitantly disrupt hepatic lipid output through defects in VLDL assembly and, most probably, secretion. The results also point to a defect in hepatic bile acid secretion. The present study offers novel insights into intrahepatic lipid metabolism, which may be relevant to metabolic complications found in postmenopausal women.

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.

Coumarin is a natural compound abundant in plant-based foods such as citrus fruits, tomatoes, vegetables and green tea. Although coumarin has been reported to exhibit anti-coagulant, anti-inflammation and cholesterol-lowering properties, the effect of coumarin on hepatic lipid metabolism remains unclear. In the present study, we evaluated the ability of coumarin to protect against hepatic steatosis associated with a high-fat diet (HFD) and investigated potential mechanisms underlying this effect. C57BL/6J mice were fed a normal diet, HFD and HFD containing 0·05 % courmarin for 8 weeks. The present results showed that coumarin reduced weight gain and abdominal fat mass in mice fed the HFD for 8 weeks (P< 0·05). Coumarin also significantly reduced the HFD-induced elevation in total cholesterol, apoB, leptin and insulin (P< 0·05). In the liver of HFD-fed mice, coumarin significantly reduced total lipids, TAG and cholesterol (38, 22 and 9 % reductions, respectively; P< 0·05), as well as lipid droplet number and size. Additionally, thiobarbituric acid-reactive substance levels, as an indicator of hepatic steatosis, were attenuated by coumarin (P< 0·05). Finally, coumarin suppressed the HFD-induced up-regulation in fatty acid synthase (FAS) activity, and the expression of sterol regulatory element-binding protein-1, FAS, acetyl-CoA carboxylase 1, PPARγ and CCAAT/enhancer-binding protein-α in the liver. Taken together, these results demonstrate that coumarin could prevent HFD-induced hepatic steatosis by regulating lipogenic gene expression, suggesting potential targets for preventing hepatic steatosis.

Consumption of a high-fat diet (HFD) enriched in saturated fat induces excessive weight gain due to adiposity, which can lead to metabolic complications, as well as increased risk of fatty liver disease and CVD. The present study investigated the underlying mechanism and dose–response effects of resveratrol (RV) on obesity, hepatic steatosis and dyslipidaemia in mice fed a HFD. Male C57BL/6J mice were fed a normal diet or a HFD (20 % fat, w/w) combined with 0·005 or 0·02 % (w/w) RV for 10 weeks. As expected, mice fed a HFD developed obesity, as shown by increased body weight gain, visceral fat, hepatic fat and plasma cholesterol. RV significantly reduced visceral fat and plasma NEFA. In the liver of HFD-fed mice, RV significantly reduced TAG and cholesterol, as well as lipid droplet number and size. A low dose of RV (0·005 %) appeared to be more effective than a higher dose of RV (0·02 %) for suppressing adiposity and hepatic steatosis development with a significant decrease in body weight gain, plasma TAG and total cholesterol levels. These changes were seemingly attributable to a suppression of the fatty acid (FA) synthase, glucose-6-phosphate dehydrogenase, and phosphatidate phosphohydrolase and/or an activation of FA oxidation in the liver and epididymal adipose tissue. In conclusion, daily consumption of a low dose of RV is effective for protecting against diet-induced obesity, hepatic steatosis and dyslipidaemia in HFD-fed mice.

American mink (Neovison vison) develop fatty liver quickly in response to food deprivation, which results in preferential mobilisation of n-3 PUFA. The altered n-3:n-6 PUFA ratio in the liver may activate the endocannabinoid system resulting in increased lipid synthesis. The objective of the present study was to investigate the effects of feeding intensity (80 or 120 % RDA), dietary fat source (n-3, n-6 or n-9 fatty acids (FA)) and short-term fasting (1–7 d) on hepatic de novo lipogenesis (DNL) and the development of fatty liver in mink. Significantly elevated expression of mRNA encoding for acetyl-CoA carboxylase-1 (ACC-1) and FA synthase (FAS) was observed in the liver of mink fasted for 5–7 d, while upon re-feeding for 28 d after a 7 d food deprivation, DNL returned to pre-fasting levels. The females had a higher expression of ACC-1 and FAS mRNA than the males. In the non-fasted animals, dietary fat source and feeding intensity had significant effects on ACC-1 mRNA. The highest levels were observed in the mink fed the rapeseed oil (n-9) diet at 80 % RDA, while the lowest levels were seen when the same diet was fed at 120 % RDA. For FAS, the highest gene expression was seen in the fasted mink fed at 80 % RDA and the lowest in the non-fasted mink fed at 80 %. It is concluded that short-term food deprivation induces hepatic lipidosis in mink and that during this process, hepatic DNL further exacerbates liver fat accumulation.

The worldwide obesity epidemic over the last 20 years has led to a dramatic increase in the prevalence of non-alcoholic fatty liver disease, the hepatic manifestation of the metabolic syndrome. Estimates of prevalence vary depending on the population studied and the methods used to assess hepatic fat content, but are commonly quoted as between 10 and 30% of the adults in the Western hemisphere. Fatty liver develops when fatty acid uptake and synthesis in the liver exceeds fatty acid oxidation and export as TAG. Studies of pathogenesis point to insulin resistance, lipotoxicity, oxidative stress and chronic inflammation being central to the development and progression of the disease. A proportion of individuals with fatty liver develop progressive disease, though large prospective longitudinal studies are lacking. Nevertheless, fatty liver is associated with increased all-cause and liver-related mortality compared with the general population. Management of fatty liver centres around lifestyle and dietary measures to induce controlled and sustained weight loss. Management of cardiovascular risk factors aims to reduce mortality, while certain dietary interventions have been shown to reduce steatosis and inflammation. Specific pharmacological treatments also show promise, but their use is not widespread. A multi-system and multi-disciplinary approach to the management of this disorder is proposed.

Conjugated linoleic acid (CLA) isomers have been reported to reduce body weight and beneficially affect glucose metabolism in animals, but the results are inconsistent and seem to depend on animal model and type of CLA isomer. In the present study, feeding male Zucker fa/fa rats diets supplemented with 1 % trans-10, cis-12-CLA for 10 d reduced the liver TAG content without improving the overall adiposity, and enhanced hepatic mitochondrial and peroxisomal β-oxidation. The increased carnitine palmitoyltransferase (CPT)-I activity and mRNA level as well as the increased n-3:n-6 PUFA ratio in liver suggest that trans-10, cis-12-CLA increased the hepatic β-oxidation by stimulation of PPARα. The reduced hepatic TAG content may be partly due to lower activity of stearoyl-CoA desaturase, as the ratios of 18 : 1n-9:18 : 0 and 16 : 1n-7:16 : 0 were reduced in liver. Trans-10, cis-12-CLA increased the CPT-I mRNA in retroperitoneal white adipose tissue (WAT), and increased uncoupling protein-2 mRNA in epididymal and inguinal WAT depots. Leptin mRNA level was decreased in all examined WAT depots, implying reduced insulin sensitivity. The resistin mRNA level was increased in all WAT depots, whereas adiponectin mRNA was reduced in inguinal and retroperitoneal WAT. The present results suggest that dietary supplementation with trans-10, cis-12-CLA may increase the catabolism of lipids in liver and adipose tissue. Moreover, we provide new data suggesting that trans-10, cis-12-CLA modulates the expression of resistin and adiponectin inversely in adipose tissue. Hence, the present results suggest that trans-10, cis-12-CLA may have some beneficial effects on lipid metabolism and adiposity but possibly reduces insulin sensitivity.

The purpose of the present study was to determine the time course of changes in in vitro lipolysis and in perilipin content (Western blot) in the mesenteric and/or the retroperitoneal fat depots in relation to the development of hepatic steatosis in high-fat diet-fed rats. Female Sprague-Dawley rats were submitted to a high-fat diet (HF diet; 42% as kJ) or a standard diet (SD diet) for 1, 2, 3 or 8 weeks. Fat accretion in the mesenteric and retroperitoneal tissues was higher (P<0·01) in HF diet-fed than in SD diet-fed rats as soon as 1 week after the beginning of the diet. Liver triacylglycerol concentrations were significantly (P<0·01) higher in HF diet-fed than in SD diet-fed rats throughout the experiment, the highest values being reached at week 2 of the diet. Basal and stimulated lipolysis (10−4 to 10−7m-isoproterienol) in the mesenteric and retroperitoneal fat depots was not changed during the first 3 weeks, regardless of the diet. Lipolysis in the mesenteric adipose tissue in the basal and stimulated states was, however, higher (P<0·01) in HF diet-fed than in SD diet-fed rats after 8 weeks of the diets. There were no significant (P>0·05) effects of diet and time on perilipin content of mesenteric tissue. In spite of a rapid fat accretion, the present results do not provide any evidence of a rapid (3 weeks) increase in in vitro lipolysis in intra-abdominal fat depots upon the undertaking of an HF diet at a time where liver lipid infiltration is the most significant.