BackgroundNonalcoholic fatty liver disease (NAFLD) is a major public health concern in western societies. Nonalcoholic steatohepatitis (NASH), the progressive form of NAFLD, is characterized by hepatic steatosis, inflammation, oxidative stress and fibrosis. NASH is a risk factor for cirrhosis and hepatocellular carcinoma. NASH is predicted to be the leading cause of liver transplants by 2020. Despite this growing public health concern, there remain no Food and Drug Administration (FDA) approved NASH treatments. Using Ldlr -/- mice as a preclinical model of western diet (WD)-induced NASH, we previously established that dietary supplementation with docosahexaenoic acid (DHA, 22:6,ω3) attenuated WD-induced NASH in a prevention study. Herein, we evaluated the capacity of DHA supplementation of the WD and a low fat diet to fully reverse NASH in mice with pre-existing disease.MethodsLdlr -/- mice fed the WD for 22 wks developed metabolic syndrome (MetS) and a severe NASH phenotype, including obesity, dyslipidemia, hyperglycemia, hepatic steatosis, inflammation, fibrosis and low hepatic polyunsaturated fatty acid (PUFA) content. These mice were randomized to 5 groups: a baseline group (WDB, sacrificed at 22 wks) and 4 treatments: 1) WD + olive oil (WDO); 2) WD + DHA (WDD); 3) returned to chow + olive oil (WDChO); or 4) returned to chow + DHA (WDChD). The four treatment groups were maintained on their respective diets for 8 wks. An additional group was maintained on standard laboratory chow (Reference Diet, RD) for the 30-wk duration of the study.ResultsWhen compared to the WDB group, the WDO group displayed increased hepatic expression of genes linked to inflammation (Opn, Il1rn, Gdf15), hepatic fibrosis (collagen staining, Col1A1, Thbs2, Lox) reflecting disease progression. Mice in the WDD group, in contrast, had increased hepatic C20-22 ω3 PUFA and no evidence of NASH progression. MetS and NASH markers in the WDChO or WDChD groups were significantly attenuated and marginally different from the RD group, reflecting disease remission.ConclusionWhile these studies establish that DHA supplementation of the WD blocks WD-induced NASH progression, DHA alone does not promote full remission of diet-induced MetS or NASH.

Obese and type 2 diabetic (T2DM) patients have a high prevalence of nonalcoholic fatty liver disease (NAFLD). NAFLD is a continuum of chronic liver diseases ranging from benign hepatosteatosis to nonalcoholic steatohepatitis (NASH), cirrhosis and primary hepatocellular cancer (HCC). Because of its strong association with the obesity epidemic, NAFLD is rapidly becoming a major public health concern worldwide. Surprisingly, there are no FDA approved NAFLD therapies; and current therapies focus on the co-morbidities associated with NAFLD, namely, obesity, hyperglycemia, dyslipidemia, and hypertension. The goal of this review is to provide background on the disease process, discuss human studies and preclinical models that have examined treatment options. We also provide an in-depth rationale for the use of dietary ω3 polyunsaturated fatty acid (ω3 PUFA) supplements as a treatment option for NAFLD. This focus is based on recent studies indicating that NASH patients and preclinical mouse models of NASH have low levels of hepatic C ω3 PUFA. This decline in hepatic PUFA may account for the major phenotypic features associated with NASH, including steatosis, inflammation and fibrosis. Finally, our discussion will address the strengths and limitations of ω3 PUFA supplements use in NAFLD therapy.

This article is available online at http://www.jlr.org mainly as neutral lipids consisting of triacylglycerols, cholesterol esters, and diacylglycerols. NAFLD ranges in severity from benign hepatosteatosis to nonalcoholic steatohepatitis (NASH) ( 1 ). NASH is defi ned as hepatosteatosis with infl ammation and hepatic injury ( 2 ). Although simple hepatosteatosis is considered clinically benign, NASH is the progressive form of the disease that can lead to significant changes in hepatic morphology (hepatocyte ballooning) and injury (cell death and fi brosis).The incidence of NAFLD has increased in parallel with the obesity epidemic in Western societies. In the general population, the prevalence of NAFLD is estimated to range from 6 to 33% ( 3 ), and ‫ف‬ 30-40% of individuals with hepatic steatosis progress to NASH ( 4 ). The prevalence of NASH ranges from 3 to 5% in the general population ( 3 ). NAFLD and NASH have high prevalence ( у 60%) in patients with type 2 diabetes ( 5 ). Additionally, NASH patients have higher mortality rates than NAFLD patients ( 6-8 ), and over a 10 year period, cirrhosis and liver-related death occurs in 20 and 12% of NASH patients, respectively ( 9 ). Because NASH can progress to cirrhosis, hepatocellular cancer, and liver failure ( 4,(10)(11)(12)(13)(14), it is the third most common cause for liver transplantation. NASH is projected to be the leading cause of liver transplantation in the United States by 2020 ( 15 ).Hepatic fi brosis involves the increased production of extracellular matrix (ECM) from activated hepatic stellate cells and myofi broblasts infi ltrating the liver. The liver has an underlayment of connective tissue composed of several Nonalcoholic fatty liver disease (NAFLD) is a signifi cant public health burden in Western societies. NAFLD is defi ned as excess accumulation of liver fat (hepatosteatosis),

The objective of this experiment was to compare fatty acid (FA) concentrations in plasma and reproductive tissues as well as hormones and expression of genes associated with pregnancy establishment in beef cows supplemented or not with Ca salts of soybean oil (CSSO) beginning after timed AI. Ninety nonlactating multiparous Nelore (Bos indicus) cows were timed inseminated on d 0 of the experiment and divided into 18 groups of 5 cows/group. Groups were randomly assigned to receive (as-fed basis) 100 g of a protein-mineral mix plus 100 g of ground corn per cow daily in addition to 1) 100 g/cow daily of CSSO (n = 9) or 2) 100 g/cow daily of kaolin (CON; rumen-inert indigestible substance; n = 9). All groups were maintained in a single Brachiaria brizanta pasture (24 ha) with ad libitum access to forage and water. However, groups were segregated daily and offered treatments individually at the working facility during the experimental period (d 0 to 18). Blood samples were collected and transrectal ultrasonography was performed to verify ovulation and estimate corpus luteum (CL) volume immediately before AI (d 0) and on d 7 and 18 of the experiment. On d 19, 36 cows (18 cows/treatment; 2 cows/group) diagnosed without the presence of a CL on d 0 but with a CL greater than 0.38 cm(3) in volume on d 7 and 18 were slaughtered for collection of conceptus, uterine luminal flushing, and tissue samples from the CL and endometrium. Cows receiving CSSO had greater concentrations of linoleic and other ω-6 FA in plasma (P < 0.01), endometrium (P ≤ 0.05), CL (P ≤ 0.05), and conceptus (P ≤ 0.08) compared to CON. On d 7 of the experiment, CSSO-supplemented cows had greater plasma progesterone concentrations (P < 0.01) and CL volume (P = 0.02) compared to CON, whereas no treatment effects were detected (P ≥ 0.15) for these parameters on d 18 (treatment × day interaction; P < 0.01). Cows receiving CSSO tended (P = 0.09) to have greater concentrations of interferon-tau in the uterine flushing media compared with CON. However, no treatment effects were detected for mRNA expression genes associated with pregnancy establishment in endometrial, CL, and conceptus samples (P ≥ 0.12). In summary, supplementing beef cows with 100 g of CSSO beginning after AI favored incorporation of ω-6 FA into their circulation, reproductive tissues, and conceptus, without impacting expression of genes associated with pregnancy establishment on d 19 of gestation.

Nonalcoholic fatty liver disease (NAFLD) has increased in parallel with central obesity, and its prevalence is anticipated to increase as the obesity epidemic remains unabated. NAFLD is now the most common cause of chronic liver disease in developed countries and is defined as excessive lipid accumulation in the liver, that is, hepatosteatosis. NAFLD ranges in severity from benign fatty liver to nonalcoholic steatohepatitis (NASH), and NASH is characterized by hepatic injury, inflammation, oxidative stress, and fibrosis. NASH can progress to cirrhosis, and cirrhosis is a risk factor for primary hepatocellular carcinoma (HCC). The prevention of NASH will lower the risk of cirrhosis and NASH-associated HCC. Our studies have focused on NASH prevention. We developed a model of NASH by using mice with the LDL cholesterol receptor gene ablated fed the Western diet (WD). The WD induces a NASH phenotype in these mice that is similar to that seen in humans and includes robust induction of hepatic steatosis, inflammation, oxidative stress, and fibrosis. With the use of transcriptomic, lipidomic, and metabolomic approaches, we examined the capacity of 2 dietary ω-3 (n-3) polyunsaturated fatty acids, eicosapentaenoic acid (20:5ω-3; EPA) and docosahexaenoic acid (22:6ω-3; DHA), to prevent WD-induced NASH. Dietary DHA was superior to EPA at attenuating WD-induced changes in plasma lipids and hepatic injury and at reversing WD effects on hepatic metabolism, oxidative stress, and fibrosis. The outcome of these studies suggests that DHA may be useful in preventing NASH and reducing the risk of HCC.