Combination of Alcohol and Fructose Exacerbates Metabolic Imbalance in Terms of Hepatic Damage, Dyslipidemia, and Insulin Resistance in Rats

and Insulin Resistance in Rats. PLoS ONE 9(8): e104220. doi:10.1371/journal.pone.0104220 Combination of Alcohol and Fructose Exacerbates Metabolic Imbalance in Terms of Hepatic Damage, Dyslipidemia, and Insulin Resistance in Rats Salamah Mohammad Alwahsh 0 Min Xu 0 Frank Christian Schultze 0 Jo rg Wilting 0 Sabine Mihm 0 Dirk Raddatz 0 Giuliano Ramadori 0 0 1 Department Gastroenterology and Endocrinology, University Medical Center Goettingen , Goettingen, Germany , 2 Department of General, Visceral, and Pediatric Surgery, University Medical Center Goettingen , Goettingen, Germany , 3 Institute of Anatomy and Cell Biology, University Medical Center Goettingen , Goettingen , Germany Although both alcohol and fructose are particularly steatogenic, their long-term effect in the development of a metabolic syndrome has not been studied in vivo. Consumption of fructose generally leads to obesity, whereas ethanol can induce liver damage in the absence of overweight. Here, Sprague-Dawley rats were fed ad libitum for 28 days on five diets: chow (control), liquid Lieber-DeCarli (LDC) diet, LDC +30%J of ethanol (L-Et) or fructose (L-Fr), and LDC combined with 30%J ethanol and 30%J fructose (L-EF). Body weight (BW) and liver weight (LW) were measured. Blood and liver samples were harvested and subjected to biochemical tests, histopathological examinations, and RT-PCR. Alcohol-containing diets substantially reduced the food intake and BW (#3rd week), whereas fructose-fed animals had higher LW than controls (P, 0.05). Additionally, leukocytes, plasma AST and leptin levels were the highest in the fructose-administered rats. Compared to the chow and LDC diets, the L-EF diet significantly elevated blood glucose, insulin, and total-cholesterol levels (also vs. the LEt group). The albumin and Quick-test levels were the lowest, whereas ALT activity was the highest in the L-EF group. Moreover, the L-EF diet aggravated plasma triglyceride and reduced HDL-cholesterol levels more than 2.7-fold compared to the sum of the effects of the L-Et and L-Fr diets. The decreased hepatic insulin clearance in the L-EF group vs. control and LDC groups was reflected by a significantly decreased C-peptide:insulin ratio. All diets except the control caused hepatosteatosis, as evidenced by Nile red and H&E staining. Hepatic transcription of insulin receptor substrate-1/2 was mainly suppressed by the L-Fr and L-EF diets. The L-EF diet did not enhance the mitochondrial b-oxidation of fatty acids (Cpt1a and Ppar-a expressions) compared to the L-Et or L-Fr diet. Together, our data provide evidence for the coaction of ethanol and fructose with a high-fat-diet on dyslipidemia and insulin resistance-accompanied liver damage. - Data Availability: The authors confirm that all data underlying the findings are fully available without restriction. All relevant data are within the paper and its Supporting Information files. Funding: This study was financed by UMG budget resources. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. . These authors contributed equally to this work. Currently, fast-food meals, which are characterized by standardized palatability, high contents of fat and sugar, large portion sizes and high energy densities [1], are frequently consumed with alcoholic beverages. The number of fast food outlets and sales has increased over the past 30 years due to aspects of convenience, such as time-saving, minimal waiting, easy purchasing through self-service or carry-out eating venues [2,3]. Fast-food consumption is associated with weight gain and insulin resistance (IR) in humans [4]. Furthermore, feeding experimental animals with a cafeteria diet leads to liver damage [5]. Nutrients may have dual influences on the body, acting either as a benefit or risk for life sustainability, according to the type and amount of consumed dietary ingredients. The consumption of fructose beverages favors the increasing prevalence of metabolic syndrome and such accompanying diseases as nonalcoholic fatty liver disease (NAFLD) [6]. NAFLD is defined as the accumulation of lipid in the liver of individuals who do not consume significant amounts of alcohol (3040 g/day) [7] and in whom other known causes of steatosis, such as certain drugs and toxins, have been excluded [8]. NAFLD which can progress to liver cancer, is a multifactorial disease that involves complex processes of the genetics, diet, and lifestyle [9]. The pathogenesis of NAFLD and the efficacy and safety of its pharmacotherapy remain elusive [10]. The Western-style diet is often enriched in both, saturated fat and sugar. The total caloric intake plays an important role in the development of NAFLD [11]. In the United States, the ingestion of fructose has increased by approximately fivefold between 1975 and 2000 [12]. Fructose, a fruit sugar, is commonly used as a sweetener, e.g., in high-fructose corn syrup [13]. It is frequently found in soft drinks and juice beverages and can be integrated into convenient, pre-packaged food. The term soft drink encompasses sodas (carbonated beverages, e.g., Colas) and other sugarsweetened beverages such as fruit drinks and lemonade [14]. As fructose has been demonstrated to induce NAFLD in both humans [7]and animals [15,16]; it should be studied more closely. In addition to fructose-enriched meals, alcoholic (ethanolic) beverages are also consumed regularly by a large proportion of the population. In many countries, light-to-moderate alcohol consumption is considered to be an integral part of the diet [17]. Beer is the worlds most widely consumed alcoholic beverage and generally contains 46% (v/v) alcohol [18]. The amount of ethanol consumed determines its role in the nutritional balance; therefore, alcohol abuse leads to alcoholic fatty liver disease (AFLD) [19]. However, the effects of light alcohol consumption (e.g., ,140 g/ week) [20] on NAFLD have not been well documented, and in particular, its combination with a (high) fructose diet has not been determined. As people consume various types of food, we sought to develop and characterize models of fatty liver based on nutritional compositions resembling those of fast food, Western-style diets and alcoholic beverages, using a multipurpose outbred rat stock. We experimentally compared the effects of selected nutrients, their relative contribution and interaction, and metabolic regulatory pathways on the development of hepatic damage and insulin resistance, and metabolic syndrome. Materials and Methods Animals Ten-week old male Sprague-Dawley rats (270310 g) were purchased from Charles River, Sulzfeld, Germany. The rats were housed individually at 24uC in conventional cages under a 12:12 h light-dark schedule. All animals received humane care according to the criteria outlined in the Guide for the Care and Us (...truncated)