Hepatic Gene Expression Levels Research Articles

Dietary Lycium barbarum Polysaccharide Modulates Growth Performance, Antioxidant Capacity, and Lipid Metabolism in Common Carp (Cyprinus carpio) Fed with High-Fat Diet.

To investigate the ameliorative effects and mechanism of Lycium barbarum polysaccharide (LBP) on growth performance, oxidative stress, and lipid deposition in common carp (Cyprinus carpio) fed with high-fat diets, fish with an initial weight of 5.29 ± 0.12 g were divided into five experimental groups-including normal-fat diets, high-fat diets, and high-fat diets-supplemented with LBP (0.5, 1.0, and 2.0 g/kg) for 8 weeks. The results showed that high-fat diets resulted in significant decreases in final body weight, weight gain rate, and specific growth rate of fish, as well as causing a significant decrease in hepatic total antioxidant capacity, catalase, and glutathione peroxidase activities. These changes were accompanied by a significant decrease in lipase activity and ATP level and a significant increase in malondialdehyde content. The expression levels of lipid metabolism-related genes (acetyl coenzyme A carboxylase 1, stearoyl coenzyme A desaturase 1, fat synthase, peroxisome proliferator-activated receptor-γ, fructofuranose bisphosphatase, and glucose-6-phosphatase) were also markedly elevated by high-fat diets. Supplementation with 0.5-2.0 g/kg LBP in high-fat diets improved the reduced growth performance, increased hepatic total antioxidant enzymes, catalase, and glutathione peroxidase activities, and lowered malondialdehyde level in fish fed with high-fat diets. Additionally, dietary supplementation with LBP significantly downregulated hepatic gene expression levels of acetyl coenzyme A carboxylase 1, stearoyl coenzyme A desaturase 1, fat synthase, sterol regulatory element-binding protein 1, peroxisome proliferator-activated receptor-γ, fructofuranose bisphosphatase, and glucose-6-phosphatase. In conclusion, fish fed with high-fat diets demonstrated impaired growth performance, antioxidant capacity, and lipid metabolism, and dietary supplementation with 0.5-2.0 g/kg LBP ameliorated the impairments induced by high-fat diets.

Sex and genotype dependent differences in amyloid beta levels and lipid metabolism in type 2 diabetic APPxhQC transgenic mice

AbstractBackgroundAccumulation of amyloid beta (Aβ) and tau proteins have for decades been thought to be central in the pathogenesis of Alzheimer’s disease (AD). More recently, a plethora of evidence emerged that links metabolic dysfunctions such as obesity, type 2 diabetes (T2D), and dyslipidemia with the pathophysiology of AD. In this study, we investigated the effects of streptozocin and high fat diet (HFD) induced T2D on lipid and amyloid beta metabolism in APPxhQC transgenic mice and their wild‐type littermates.MethodAPPxhQC mice were generated by crossbreeding APPSL with hQC mice. As controls wild‐type littermates were used. APPSL mice express human APP751 with the Swedish and the London mutation on a C57Bl/6RccHsd background. hQC mice express human glutaminyl cyclase (QC) enzyme on B6CBAF1/J background. Plasma lipids (triglycerides and cholesterol) and liver function enzymes (aspartate aminotransferase and alanine transaminase, ALT and ALT, respectively) were determined by ELISA. Brain concentrations of soluble and insoluble Aβ 1‐38, 1‐40 and 1‐42 peptides were determined using an immunosorbent assay (Mesoscale discovery immunosorbent assay) while pGlu Aβ1‐42 was measured by ELISA. Hepatic mRNA expression levels of genes involved in cholesterol efflux and lipid metabolism were determined by quantitative real time polymerase chain reaction (qRT‐PCR).ResultT2D induced increased concentrations of plasma cholesterol as well as AST and ALT levels. The magnitudes, however, were dependent on sex and genotype and were statistically significant in female wild‐type mice, while a similar pattern was observed in APPxhQC transgenes. These increased plasma concentrations were accompanied by a down‐regulation of hepatic gene expression levels of LRP1, ABCA1, PPARα, PBC1β, and NEP that were statistically significant in female wild‐type mice, while a similarly pattern was observed in APPxhQC transgenic mice. More interestingly, T2D provoked a progressive shift of brain Aβ 1‐38 and 1‐40 from soluble to insoluble forms in male APPxhQC mice and a significant increase of pyroglutamate modified Aβ 1‐42 in female mice.ConclusionT2D in APPxhQC mice provokes a shift from soluble to large insoluble polymers of Aβ in the brain, corroborates the deteriorating role of T2D in the progression of AD

3D bioprinting of dECM-incorporated hepatocyte spheroid for simultaneous promotion of cell-cell and -ECM interactions.

The cell spheroid technology, which greatly enhances cell-cell interactions, has gained significant attention in the development of in vitro liver models. However, existing cell spheroid technologies still have limitations in improving hepatocyte-extracellular matrix (ECM) interaction, which have a significant impact on hepatic function. In this study, we have developed a novel bioprinting technology for decellularized ECM (dECM)-incorporated hepatocyte spheroids that could enhance both cell-cell and -ECM interactions simultaneously. To provide a biomimetic environment, a porcine liver dECM-based cell bio-ink was developed, and a spheroid printing process using this bio-ink was established. As a result, we precisely printed the dECM-incorporated hepatocyte spheroids with a diameter of approximately 160-220μm using primary mouse hepatocyte (PMHs). The dECM materials were uniformly distributed within the bio-printed spheroids, and even after more than 2weeks of culture, the spheroids maintained their spherical shape and high viability. The incorporation of dECM also significantly improved the hepatic function of hepatocyte spheroids. Compared to hepatocyte-only spheroids, dECM-incorporated hepatocyte spheroids showed approximately 4.3- and 2.5-fold increased levels of albumin and urea secretion, respectively, and a 2.0-fold increase in CYP enzyme activity. These characteristics were also reflected in the hepatic gene expression levels of ALB, HNF4A, CPS1, and others. Furthermore, the dECM-incorporated hepatocyte spheroids exhibited up to a 1.8-fold enhanced drug responsiveness to representative hepatotoxic drugs such as acetaminophen, celecoxib, and amiodarone. Based on these results, it can be concluded that the dECM-incorporated spheroid printing technology has great potential for the development of highly functional in vitro liver tissue models for drug toxicity assessment.

Effects of Melatonin on Liver of D-Galactose-Induced Aged Mouse Model.

Melatonin, a hormone secreted by the pineal gland of vertebrates, regulates sleep, blood pressure, and circadian and seasonal rhythms, and acts as an antioxidant and anti-inflammatory agent. We investigated the protective effects of melatonin against markers of D-galactose (D-Gal)-induced hepatocellular aging, including liver inflammation, hepatocyte structural damage, and non-alcoholic fatty liver. Mice were divided into four groups: phosphate-buffered saline (PBS, control), D-Gal (200 mg/kg/day), melatonin (20 mg/kg), and D-Gal (200 mg/kg) and melatonin (20 mg) cotreatment. The treatments were administered once daily for eight consecutive weeks. Melatonin treatment alleviated D-Gal-induced hepatocyte impairment. The AST level was significantly increased in the D-Gal-treated groups compared to that in the control group, while the ALT level was decreased compared to the melatonin and D-Gal cotreated group. Inflammatory genes, such as IL1-β, NF-κB, IL-6, TNFα, and iNOS, were significantly increased in the D-Gal aging model, whereas the expression levels of these genes were low in the D-Gal and melatonin cotreated group. Interestingly, the expression levels of hepatic steatosis-related genes, such as LXRα, C/EBPα, PPARα, ACC, ACOX1, and CPT-1, were markedly decreased in the D-Gal and melatonin cotreated group. These results suggest that melatonin suppresses hepatic steatosis and inflammation in a mouse model of D-Gal-induced aging.

Beneficial effects of silibinin on serum lipids, bile acids, and gut microbiota in methionine-choline-deficient diet-induced mice.

Silibinin (SIL) is a flavonoid lignin isolated from the fruit and seeds of silybum marianum that exhibits good therapeutic potential for NASH. However, the effects of SIL on serum lipids, bile acids (BAs), and gut microbiota (GM) in NASH mice remain unknown. The present work aimed to explore the beneficial effects of SIL supplementation on serum lipids, bile acids, and gut microbiota in MCD mice. After male C57BL/6 mice were fed with a methionine-choline deficient (MCD) diet and simultaneously gavaged with SIL (20 mg/kg. d) for 8 weeks, the pathological changes of liver tissue were observed by oil red O, haematoxylin-eosin, and Masson tricolor staining; the levels of serum AST and ALT, and liver TG and MDA were detected by assay kits; metabonomics and 16S rDNA sequencing were used to analyze the composition of serum lipids and BAs and the abundance of GM; and the mRNA expression levels of hepatic genes related to BAs homeostasis were detected by RT-qPCR. The results indicated that SIL treatment decreased the levels of 26 lipids (including four arachidonic acids, seven FFAs, 12 acyl carnitines, and three GPs) and two BAs (23-DCA, GLCA), while Dubosiella increased the levels of 10 lipids (including TxB3, PG16:0_18:1, Cer t18:0/24:0 and 7 TGs), five BAs (β-MCA, α-MCA, UDCA, 3-oxo-DCA and HCA), and two GMs (Verrucomicrobiota and Akkermansiaceae) of MCD mice, but had no significant effect on the mRNA expression of CYP7A1, CYP27A1, Bsep, Mrp2, Ntcp, or Oatp1b2. Therefore, influencing GM composition and then regulating the levels of serum lipids and BAs through enterohepatic axis should be an important mechanism of SIL-induced alleviative effect on MCD mice. More importantly, we found that SIL had a good coordination in regulating the abundance of GM and the contents of serum lipids and BAs in MCD mice, that is, when the abundance of probiotics was up-regulated, the content of beneficial unsaturated fatty acids in serum was up-regulated, while the serum levels of harmful lipids and BAs were down-regulated. The alleviating effect of SIL on NASH may be closely related to the correction of intestinal bacteria disorder, serum bile acid, and lipid metabolic disturbance in mice.

IL-6 mediates the hepatic acute phase response after prerenal azotemia in a clinically-defined murine model.

Prerenal azotemia (PRA) is a major cause of acute kidney injury (AKI) and uncommonly studied in preclinical models. We sought to develop and characterize a novel model of PRA that meets the clinical definition: acute loss of GFR that returns to baseline with resuscitation. Adult male C57Bl/6J wild type (WT) and IL-6 -/- mice were studied. 4 mg of furosemide intraperitoneally (IP) or vehicle (Veh) was administered at time 0 hr and 3 hr to induce PRA from volume loss. Resuscitation began at 6 hr with 1 mL IP saline x 4 over 36 hours. Six hours after furosemide administration, measured GFR was 25% of baseline and returned to baseline after saline resuscitation at 48 hours. At 6 hours of PRA, plasma IL-6 was significantly increased, renal and liver histology were normal, renal and liver lactate were normal, and renal KIM-1 immunofluorescence was negative; 327 differentially regulated genes were upregulated in the liver and the acute phase response was the most significantly upregulated pathway; 25% of upregulated genes were suppressed in IL-6-/- mice, and the acute phase response was the most significantly suppressed pathway. Significantly upregulated genes and their proteins were also investigated and included: serum amyloid A2, serum amyloid A1, CXCL1, and haptoglobin; hepatic gene expression and plasma protein levels were all increased in WT PRA and were all reduced in IL-6-/- PRA. This work demonstrates previously unknown systemic effects of prerenal azotemia that includes IL-6-mediated upregulation of the hepatic acute phase response.

Effects of dietary n-3 LC-PUFA levels on the growth, immunity, and lipid metabolism of freshwater carnivorous teleost largemouth bass (Micropterus salmoides) juveniles

The n-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA) play important roles in the normal growth and metabolism of fish . In order to explore the appropriate requiremnts of n-3 LC-PUFA in juvenile largemouth bass Micropterus salmoides, a freshwater carnivorous teleost, four isoproteic (50 %) and isolipidic (11 %) diets were formulated. The control diet used fish oil (FO) as the sole lipid source, and the other three diets used mixed vegetable oil as the main lipid source and supplemented with 0.50 %, 0.80 % and 1.10 % n-3 LC-PUFA, respectively. After the juvenile largemouth bass (initial weight 12.11 ± 0.01 g) fed with the four diets for 75 days, the growth, serum and heptic biochemical indices, as well as hepatic lipid metabolism were investigated. The results showed that the growth performance of 0.50 %-1.10 % groups were high that of control group; comparing to the 1.10 % group, high weight gain, specific growth rate and daily gain, as well as muscle hardness, chewiness and gumminess were detected in the 0.80 % group (P < 0.05). With the increase of dietary n-3 LC-PUFA levels, the serum biochemical indices (total cholesterol, triglyceride, and aspartate aminotransferase activity) and hepatic triglyceride were significantly decreased, while the serum acid phosphatase and alkaline phosphatase, as well as hepatic and muscle n-3 LC-PUFA contents were significantly increased (P < 0.05). Compared with the 0.50 % group, high hepatic mRNA expression levels of anti-inflammatory genes (il-10, tgf-β) were observed in the 0.80 % group (P < 0.05); and the relatively high transcript levels of genes related to lipid transport and catabolism (hsl, pparα, fatp and mtp) and low transcript levels of genes related to lipid anabolism (accα and pparγ) were detected in the 0.80 % and 1.10 % groups, as well as high mRNA levels of accα and pparγ were measured in the 0.80 % group (P < 0.05). The results indicated that 0.80 % dietary n-3 LC-PUFA level is suitable for largemouth bass concerning the growth performance, muscle quality and hepatic lipid metabolism. When subjected the weight gain to the second-order polynomial regression analysis, the maximum value was achieved at 0.76 % n-3 LC-PUFA level, which provide a basis for the development of formula feed for largemouth bass.

Averrhoa carambola L. fruit polyphenols ameliorate hyperlipidemia, hepatic steatosis, and hyperglycemia by modulating lipid and glucose metabolism in mice with obesity.

Hyperlipidemia, hepatic steatosis, and hyperglycemia are common metabolic complications of obesity. The objective of the present study is to investigate the in vivo protective effect of Averrhoa carambola L. fruit polyphenols (ACFP) on hyperlipidemia, hepatic steatosis, and hyperglycemia in mice with high-fat diet (HFD)-induced obesity and elucidate the mechanisms of action underlying the beneficial effects of ACFP. Thirty-six specific pathogen-free male C57BL/6J mice (4 weeks old, weighing 17.1-19.9 g) were randomly divided into three groups and fed with a low-fat diet (LFD, 10% fat energy), HFD (45% fat energy), or HFD supplemented with ACFP by intragastric administration for 14 weeks. Obesity-related biochemical indexes and hepatic gene expression levels were determined. The statistical analyses were conducted using one-way analysis of variance (ANOVA) followed by Duncan's multiple range test. The results showed that the body weight gain, serum triglycerides, total cholesterol, glucose, insulin resistance index, and steatosis grade in the ACFP group decreased by 29.57%, 26.25%, 27.4%, 19.6%, 40.32%, and 40%, respectively, compared to the HFD group. Gene expression analysis indicated that ACFP treatment improved the gene expression profiles involved in lipid and glucose metabolism compared to the HFD group. ACFP protected from HFD-induced obesity and obesity-associated hyperlipidemia, hepatic steatosis, and hyperglycemia by improving lipid and glucose metabolism in mice. © 2023 Society of Chemical Industry.

Effects of Yellow Mealworm (Tenebrio molitor) on Growth Performance, Hepatic Health and Digestibility in Juvenile Largemouth Bass (Micropterus salmoides).

This study investigated the effects of yellow mealworm meal (TM) on growth performance, hepatic health and digestibility in juvenile largemouth bass (Micropterus salmoides). The fish were fed with the basic feed and the test feed (70% basic feed and 30% raw materials) containing Cr2O3, and feces were collected for digestibility determination. The fish were fed with five isonitrogenous (47% crude protein) and isolipidic (13% crude lipid) diets, in which fishmeal (FM) was replaced with 0% (TM0), 12% (TM12), 24% (TM24), 36% (TM36) and 48% (TM48) TM. The fish were reared in cylindrical plastic tanks in a recirculating aquaculture system for 11 weeks. The apparent digestibility coefficients (ADC), of dry matter, crude protein and crude lipid, in largemouth bass of TM were 74.66%, 91.03% and 90.91%, respectively. The ADC of total amino acid (TAA) of TM in largemouth bass was 92.89%, and the ADC of essential amino acid (EAA) in TM in largemouth bass was 93.86%. The final body weight (FBW), weight gain rate (WGR) and specific growth rate (SGR) in the TM24 group were significantly higher than those in other groups. Similarly, the highest mRNA expression levels of hepatic protein metabolism genes (pi3k, mtor, 4ebp2 and got) and antioxidant enzyme (glutathione peroxidase, Gpx; catalase, Cat) activities were observed in the TM24 group. Moreover, the expression levels of anti-inflammatory factors (il-10 and tgf) in liver were up-regulated and the expression levels of pro-inflammatory factors (il-8 and il-1β) in liver were down-regulated. Quadratic regression model analysis, based on weight gain rate (WGR) against dietary TM level, indicated that the optimum level of dietary TM replacing FM in largemouth bass diet was 19.52%. Appropriate replacement levels (less than 36%) of FM by TM in the diets can enhance the antioxidant capacity and immunity of largemouth bass. However, high levels of FM substitution with TM (more than 48%) in the feeds can damage the liver health and inhibit the growth of largemouth bass. Notably, largemouth bass has high ADC and high utilization of TM, which indicates that it is feasible to use TM as feed protein source for largemouth bass.

Mitochondrial Methionyl-tRNA Formyltransferase Deficiency Alleviates Metaflammation by Modulating Mitochondrial Activity in Mice

Various studies have revealed the association of metabolic diseases with inflammation. Mitochondria are key organelles involved in metabolic regulation and important drivers of inflammation. However, it is uncertain whether the inhibition of mitochondrial protein translation results in the development of metabolic diseases, such that the metabolic benefits related to the inhibition of mitochondrial activity remain unclear. Mitochondrial methionyl-tRNA formyltransferase (Mtfmt) functions in the early stages of mitochondrial translation. In this study, we reveal that feeding with a high-fat diet led to the upregulation of Mtfmt in the livers of mice and that a negative correlation existed between hepatic Mtfmt gene expression and fasting blood glucose levels. A knockout mouse model of Mtfmt was generated to explore its possible role in metabolic diseases and its underlying molecular mechanisms. Homozygous knockout mice experienced embryonic lethality, but heterozygous knockout mice showed a global reduction in Mtfmt expression and activity. Moreover, heterozygous mice showed increased glucose tolerance and reduced inflammation, which effects were induced by the high-fat diet. The cellular assays showed that Mtfmt deficiency reduced mitochondrial activity and the production of mitochondrial reactive oxygen species and blunted nuclear factor-κB activation, which, in turn, downregulated inflammation in macrophages. The results of this study indicate that targeting Mtfmt-mediated mitochondrial protein translation to regulate inflammation might provide a potential therapeutic strategy for metabolic diseases.

Dexamethasone potentiates the insulin-induced Srebp-1c expression in primary rat hepatocytes

The impacts of dexamethasone (Dex) and thyroid hormone T3 on the insulin-stimulated Srebp-1c expression were studied in primary rat hepatocytes. Primary hepatocytes from Sprague-Dawley rats were isolated, cultured and treated with insulin in the presence or absence of the indicated reagents over time. The mRNA levels of indicated genes were determined using real-time PCR. Insulin treatment induced the Srebp-1c expression and suppressed the Pck1 expression in a time-dependent manner. Dex treatment alone reduced the Srebp-1c expression, whereas potentiated the insulin-induced its expression, which reached to a level that was higher than the insulin alone group. On the other hand, insulin treatment completely suppressed the Dex-induced Pck1 expression in the same cells. T3 treatment did not affect the expressions of Srebp-1c and Pck1 alone or in the presence of absence of insulin or Dex. Interestingly, insulin treatment induced the Rxrg mRNA expression level in the absence or presence of T0901317, a specific agonist for the liver X receptor. Dex and insulin mutually affect each other’s ability to regulate the expression levels of hepatic genes involved in glucose and fatty acid metabolism. Insulin induced Rxrg expression in primary hepatocytes, which may contribute to the induction of Srebp-1c expression in the same cells.

Dietary olive oil intake induces female-specific hepatic lipid accumulation without metabolic impairment in mice

Olive oil is one of the most widely researched Mediterranean diet components in both experimental models and clinical studies. However, the relationship between dietary olive oil intake and liver function in a healthy state of the body remains unclear. Because men are at a greater risk of developing hepatic diseases than women, and because hepatic metabolism is regulated by sex hormones, we hypothesized that olive oil-induced changes in hepatic metabolism would differ by sex. To test our hypothesis, 12-week-old C57BL/6JJcl male and female mice were fed an olive oil diet for 4 weeks. Blood was collected and serum biochemical components were analyzed. Hepatic lipid accumulation was determined via histological analysis using Sudan III staining. Finally, transcript expression levels of hepatic metabolism-related genes were analyzed using quantitative polymerase chain reaction. We observed significant increased hepatic lipid droplet accumulation in olive oil-fed female mice. Serum biochemical and liver messenger RNA expression analyses revealed that the hepatic lipid accumulation was nonpathological and did not involve inflammation. Moreover, the expression of genes related to triacylglycerol and fatty acid synthesis (Dgat1, Dgat2, Agpat3, and Fasn) was significantly upregulated in the liver of olive oil-fed female mice compared with control female mice. Our study demonstrates female-specific hepatic lipid accumulation without liver impairment in a dietary olive oil-fed mouse model. These findings provide a deeper mechanistic understanding of sex-dependent hepatic lipid metabolism of dietary oils.

Zinc Oxide Nanoparticles and Vitamin C Ameliorate Atrazine-Induced Hepatic Apoptosis in Rat via CYP450s/ROS Pathway and Immunomodulation

Atrazine, as an herbicide, is used widely worldwide. Because of its prolonged persistence in the environment and accumulation in the body, atrazine exposure is a potential threat to human health. The present study evaluated the possible protective effects of zinc oxide nanoparticles and vitamin C against atrazine-induced hepatotoxicity in rats. Atrazine administered to rats orally at a dose of 300 mg/kg for 21 days caused liver oxidative stress as it increased malondialdehyde (MDA) formation and decreased reduced glutathione (GSH) contents. Atrazine induced inflammation accompanied by apoptosis via upregulation of hepatic gene expression levels of NF-κB, TNF-α, BAX, and caspase-3 and downregulation of Bcl-2 gene expression levels. Additionally, it disturbed the metabolic activities of cytochrome P450 as it downregulated hepatic gene expression levels of CYP1A1, CYP1B1, CYP2E1. The liver function biomarkers were greatly affected upon atrazine administration, and the serum levels of AST and ALT were significantly increased, while BWG%, albumin, globulins, and total proteins levels were markedly decreased. As a result of the above-mentioned influences of atrazine, histopathological changes in liver tissue were recorded in our findings. The administration of zinc oxide nanoparticles or vitamin C orally at a dose of 10 mg/kg and 200 mg/kg, respectively, for 30 days prior and along with atrazine, could significantly ameliorate the oxidative stress, inflammation, and apoptosis induced by atrazine and regulated the hepatic cytochrome P450 activities. Furthermore, they improved liver function biomarkers and histopathology. In conclusion, our results revealed that zinc oxide nanoparticles and vitamin C supplementations could effectively protect against atrazine-induced hepatotoxicity.

The environmental pollutant, polychlorinated biphenyl 126, alters liver function in a rodent model of alcohol-associated liver disease.

The prevalence of alcohol-associated liver disease (ALD), a subtype of fatty liver disease (FLD), continues to rise. ALD is a major cause of preventable death. Polychlorinated biphenyl (PCB) 126 is an environmentally relevant, dioxin-like pollutant whose negative metabolic effects have been well documented. In human and animal studies,PCBhas been associated withthe severity of nonalcoholic fatty liver disease (NAFLD). However, few studies have investigated whether exposures to environmental toxicants can worsen ALD. Thus, the objective of the current study was to develop an alcohol-plus-toxicant model to study how an environmental pollutant, PCB 126, impacts rodent ALD pathology. Briefly, male C57BL/6J mice were exposed to 0.2mg/kg PCB 126 or corn oil vehicle four days prior to ethanol feeding using the chronic-binge (10-plus-one) model. Concentrations of macromolecules, including hepatic lipids, carbohydrates, and protein (albumin) were impacted. Exposure to PCB 126 exacerbated hepatic steatosis and hepatomegaly in mice exposed to the chemical and fed an ethanol diet. Gene expression and the analysis of blood chemistry showed a potential net increase and retention of hepatic lipids and reductions in lipid oxidation and clearance capabilities. Depletion of glycogen and glucose was evident, which contributes to disease progression by generating systemic malnutrition. Granulocytic immune infiltrates were present but driven solely by ethanol feeding. Hepatic albumin gene expression and plasma levels were decreased by ~50% indicating a potential compromise of liver function. Finally, gene expression analyses indicated that the aryl hydrocarbon receptor and constitutive androstane receptor were activated by PCB 126 and ethanol, respectively. Various environmental toxicants are known to modify or enhance FLD in high-fat diet models. Findings from the present study suggest that they interact with other lifestyle factors such as alcohol consumption to reprogram intermediary metabolism resulting in exacerbated ethanol-associated systemic malnutrition in ALD.

Water extract from artichoke ameliorates high-fat diet-induced non-alcoholic fatty liver disease in rats

BackgroundThe “multiple-hit” hypothesis is currently the most widely accepted theory for non-alcoholic fatty liver disease (NAFLD) pathogenesis. The present study aimed to investigate the effects of the water extract of artichoke (WEA) on NAFLD and its underlying mechanism.MethodsRats were fed a high-fat diet (HFD) for 8 weeks to induce NAFLD and then treated with WEA at three doses (0.4, 0.8, and 1.6 g/kg body weight, BW) for 8 weeks. At the end of the intervention, serum biochemical parameters, hepatic antioxidant capacity, hepatic levels of pro-inflammatory cytokines, liver histopathology, hepatic inflammatory gene and lipid metabolism gene expression, and Akt and p-Akt (S473) protein levels were determined.ResultsThe body weight, liver weight, liver triglyceride (TG) and serum levels of TG, total cholesterol, low-density lipoprotein cholesterol, alanine aminotransferase, aspartate aminotransferase, glucose, and insulin were all significantly reduced in the WEA-treated groups (0.8 and 1.6 g/kg BW) compared with the HFD group (P < 0.01). A significant decrease in hepatic content of malondialdehyde (P < 0.01) and glutathione (P < 0.01), as well as a significant increase in liver superoxide dismutase activity (P < 0.01) were observed in WEA-treated groups (0.8 and 1.6 g/kg BW) compared to the HFD group. In addition, there was a marked decrease in the hepatic levels of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in the WEA-treated groups compared to the HFD group (P < 0.01). In line with these findings, the histopathology of the livers of rats treated with WEA (0.8 and 1.6 g/kg BW) showed a decrease in steatosis, ballooning, and lobular inflammation. Mechanistically, the reduced hepatic TG content might be related to the downregulation of lipogenic genes (SREBP1c, FASN, SCD1) and upregulation of lipolytic gene (PPARα), and the improved insulin signaling might be associated with the observed increase in antioxidant activity and reduction in inflammation in the WEA-treated groups.ConclusionThe hepatoprotective role of WEA in NAFLD may be attributed to its anti-steatotic, antioxidant, anti-inflammatory, and anti-insulin resistance effects.

Influence of Fasting Time on Serum and Hepatic Lipid Profiles in a Sprague-Dawley Rat Model of Nonalcoholic Steatohepatitis.

Nonalcoholic steatohepatitis (NASH) is associated with several cardiovascular risk factors, including atherogenic dyslipidemia. Recently, fasting prior to lipid profile evaluation has been thought to be unnecessary for most individuals. We investigated the impact of fasting for up to 9 h on the serum and hepatic lipid profiles in Sprague-Dawley (SD) rats of dietary-induced NASH model in comparison to SD rats fed a normal diet. In both groups, fasting affected the serum and hepatic triglyceride (TG), serum free fatty acid (FFA) and leptin levels, histopathologically assessed hepatocyte ballooning, and hepatic mRNA expression levels of several genes related to lipid metabolism. In contrast, the serum adiponectin and aminotransferase levels, serum and hepatic total cholesterol contents, and liver histopathological findings of hepatic steatosis, lobular inflammation and fibrosis were not influenced by fasting. A significant fasting time-dependent reduction was seen in the serum TG level only in the normal SD rats group. Regarding the hepatic TG level, a significant fasting time-dependent increase was seen only in the NASH model rat group. A significant fasting time-dependent reduction was also seen in the serum FFA level only in the NASH model rat group. Our present results indicate that excessive fasting can be avoided before blood or hepatic tissue sampling for the evaluation of several parameters in non-NASH and/or NASH model rats. Further investigations are needed in humans to determine whether excessive fasting before blood or hepatic tissue sampling can be avoided in both healthy individuals and NASH patients.

Retinal degeneration induced in a mouse model of ischemia-reperfusion injury and its management by pemafibrate treatment.

Retinal ischemia-reperfusion (I/R) injury is a common cause of visual impairment. To date, no effective treatment is available for retinal I/R injury. In addition, the precise pathological mechanisms still need to be established. Recently, pemafibrate, a peroxisome proliferator-activated receptor α (PPARα) modulator, was shown to be a promising drug for retinal ischemia. However, the role of pemafibrate in preventing retinal I/R injury has not been documented. Here, we investigated how retinal degeneration occurs in a mouse model of retinal I/R injury by elevation of intraocular pressure and examined whether pemafibrate could be beneficial against retinal degeneration. Adult mice were orally administered pemafibrate (0.5mg/kg/day) for 4 days, followed by retinal I/R injury. The mice were continuously administered pemafibrate once every day until the end of the experiments. Retinal functional changes were measured using electroretinography. Retina, liver, and serum samples were used for western blotting, quantitative PCR, immunohistochemistry, or enzyme linked immunosorbent assay. Retinal degeneration induced by retinal inflammation was prevented by pemafibrate administration. Pemafibrate administration increased the hepatic PPARα target gene expression and serum levels of fibroblast growth factor 21, a neuroprotective molecule in the eye. The expression of hypoxia-response and pro-and anti-apoptotic/inflammatory genes increased in the retina following retinal I/R injury; however, these changes were modulated by pemafibrate administration. In conclusion, pemafibrate is a promising preventive drug for ischemic retinopathies.

Portulaca oleracea L. Extract Regulates Hepatic Cholesterol Metabolism via the AMPK/MicroRNA-33/34a Pathway in Rats Fed a High-Cholesterol Diet.

This study examined the effect of extruded Portulaca oleracea L. extract (PE) in rats fed a high-cholesterol diet through the AMP-activated protein kinase (AMPK) and microRNA (miR)-33/34a pathway. Sprague–Dawley rats were randomized into three groups and fed either a standard diet (SD), a high-cholesterol diet containing 1% cholesterol and 0.5% cholic acid (HC), or an HC diet containing 0.8% PE for 4 weeks. PE supplementation improved serum, liver, and fecal lipid profiles. PE upregulated the expression of genes involved in cholesterol efflux and bile acids’ synthesis such as liver X receptor alpha (LXRα), ATP-binding cassette subfamily G5/G8 (ABCG5/8), and cholesterol 7 alpha-hydroxylase (CYP7A1), and downregulated farnesoid X receptor (FXR) in the liver. In addition, hepatic gene expression levels of apolipoprotein A-l (apoA-1), paraoxonase 1 (PON1), ATP-binding cassette subfamily A1/G1 (ABCA1/G1), lecithin-cholesterol acyltransferase (LCAT), and scavenger receptor class B type 1 (SR-B1), which are related to serum high-density lipoprotein cholesterol metabolism, were upregulated by PE. Furthermore, hepatic AMPK activity in the PE group was higher than in the HC group, and miR-33/34a expression levels were suppressed. These results suggest that PE improves the cholesterol metabolism by modulating AMPK activation and miR-33/34a expression in the liver.

Hepatocyte Rap1a contributes to obesity- and statin-associated hyperglycemia.

SUMMARYExcessive hepatic glucose production contributes to the development of hyperglycemia and is a key feature of type 2 diabetes. Here, we report that activation of hepatocyte Rap1a suppresses gluconeogenic gene expression and glucose production, whereas Rap1a silencing stimulates them. Rap1a activation is suppressed in obese mouse liver, and restoring its activity improves glucose intolerance. As Rap1a′s membrane localization and activation depends on its geranylgeranylation, which is inhibited by statins, we show that statin-treated hepatocytes and the human liver have lower active-Rap1a levels. Similar to Rap1a inhibition, statins stimulate hepatic gluconeogenesis and increase fasting blood glucose in obese mice. Geranylgeraniol treatment, which acts as the precursor for geranylgeranyl isoprenoids, restores Rap1a activity and improves statin-mediated glucose intolerance. Mechanistically, Rap1a activation induces actin polymerization, which suppresses gluconeogenesis by Akt-mediated FoxO1 inhibition. Thus, Rap1a regulates hepatic glucose homeostasis, and blocking its activity, via lowering geranylgeranyl isoprenoids, contributes to statin-induced glucose intolerance.

Impacts of Circadian Gene Period2 Knockout on Intestinal Metabolism and Hepatic Antioxidant and Inflammation State in Mice.

The period circadian regulator 2 (Per2) gene is important for the modulations of rhythmic homeostasis in the gut and liver; disruption will cause metabolic diseases, such as obesity, diabetes, and fatty liver. Herein, we investigated the alterations in intestinal metabolic and hepatic functions in Per2 knockout (Per2−/−, KO) and wild-type (Per2+/+, WT) mice. Growth indices, intestinal metabolomics, hepatic circadian rhythms, lipid metabolism, inflammation-related genes, antioxidant capacity, and transcriptome sequencing were performed after euthanasia. Data indicated that KO decreased the intestinal concentrations of amino acids such as γ-aminobutyric acid, aspartic acid, glycine, L-allothreonine, methionine, proline, serine, and valine while it increased the concentrations of carbohydrates such as cellobiose, D-talose, fucose, lyxose, and xylose compared with WT. Moreover, the imbalance of intestinal metabolism further seemed to induce liver dysfunction. Data indicated that Per2 knockout altered the expression of hepatic circadian rhythm genes, such as Clock, Bmal1, Per1, Per3, Cry1, and Cry2. KO also induced hepatic lipid metabolism, because of the increase of liver index and serum concentrations of low-density lipoprotein, and the upregulated expression of Pparα, Cyp7a1, and Cpt1. In addition, KO improved hepatic antioxidant capacity due to the increase activities of SOD and GSH-Px and the decrease in concentrations of MDA. Lastly, KO increased the relative expression levels of hepatic inflammation-related genes, such as Il-1β, Il-6, Tnf-α, Myd88, and Nf-κB p65, which may potentially lead to hepatic inflammation. Overall, Per2 knockout induces gut metabolic dysregulation and may potentially trigger alterations in hepatic antioxidant and inflammation responses.