Metabolic Changes In Liver Research Articles

Metabolic perturbations prior to hepatocellular carcinoma diagnosis: Findings from a prospective observational cohort study.

Hepatocellular carcinoma (HCC) development entails changes in liver metabolism. Current knowledge on metabolic perturbations in HCC is derived mostly from case-control designs, with sparse information from prospective cohorts. Our objective was to apply comprehensive metabolite profiling to detect metabolites whose serum concentrations are associated with HCC development, using biological samples from within the prospective European Prospective Investigation into Cancer and Nutrition (EPIC) cohort (>520 000 participants), where we identified 129 HCC cases matched 1:1 to controls. We conducted high-resolution untargeted liquid chromatography-mass spectrometry-based metabolomics on serum samples collected at recruitment prior to cancer diagnosis. Multivariable conditional logistic regression was applied controlling for dietary habits, alcohol consumption, smoking, body size, hepatitis infection and liver dysfunction. Corrections for multiple comparisons were applied. Of 9206 molecular features detected, 220 discriminated HCC cases from controls. Detailed feature annotation revealed 92 metabolites associated with HCC risk, of which 14 were unambiguously identified using pure reference standards. Positive HCC-risk associations were observed for N1-acetylspermidine, isatin, p-hydroxyphenyllactic acid, tyrosine, sphingosine, l,l-cyclo(leucylprolyl), glycochenodeoxycholic acid, glycocholic acid and 7-methylguanine. Inverse risk associations were observed for retinol, dehydroepiandrosterone sulfate, glycerophosphocholine, γ-carboxyethyl hydroxychroman and creatine. Discernible differences for these metabolites were observed between cases and controls up to 10 years prior to diagnosis. Our observations highlight the diversity of metabolic perturbations involved in HCC development and replicate previous observations (metabolism of bile acids, amino acids and phospholipids) made in Asian and Scandinavian populations. These findings emphasize the role of metabolic pathways associated with steroid metabolism and immunity and specific dietary and environmental exposures in HCC development.

Co-modulation of Liver Genes and Intestinal Microbiome of Largemouth Bass Larvae (Micropterus salmoides) During Weaning.

In recent years, largemouth bass have become one of the most commonly aquacultured species in China, however, its low survival rate during larval weaning has always been a bottleneck that has restricted industrial development. Understanding the changes in liver metabolism and intestinal microflora during the weaning of largemouth bass larvae can help to design better weaning strategies and improve survival. In this study, liver mRNA and intestinal microflora 16S rRNA genes were analyzed using high-throughput sequencing at the pre, mid, and post weaning stages [15, 30, 45 days post hatching; total length (cm) were 2.21 ± 0.12, 3.45 ± 0.21, 5.29 ± 0.33, respectively]. The transcriptome results revealed that the genes with increased expression were related to amino acid metabolism in the pre-weaning stage, but they were related to fatty acid metabolism in the post-weaning stage. A similar phenomenon was observed in the intestinal microflora where the dominant microbe Proteobacteria (relative abundance 56.32%) in the pre-weaning stage was gradually replaced by Firmicutes (relative abundance 62.81%) by the post-weaning stage. In addition, the three most important digestive enzymes (trypsin, lipase, and amylase) in the intestine were significantly decreased during the mid-weaning stage (P < 0.05), which was also true for some genes crucial to immune pathways in the liver. Overall, these findings showed that weaning in largemouth bass can cause changes in liver metabolism and intestinal microbial communities, which has improved our understanding of fish adaptation to changes in food sources during weaning.

Gender-differentiated metabolic abnormalities of adult zebrafish with zinc pyrithione (ZPT) -induced hepatotoxicity

Zinc pyrithione (ZPT) is an extensively used microbicidal agent and its toxicity to multiple organs has been gradually recognized. However, details of the mechanism of ZPT toxicity are lacking and profile studies at metabolic level are still greatly limited. In this work we investigated the effects of ZPT on metabolic pathways of zebrafish liver after twenty-one days of exposure. Our integrated approach was underpinned by gas chromatography coupled with mass spectroscopy (GC-MS) and liver function analysis. Metabolomic profiles were generated from the livers of ZPT-treated zebrafish and 172 significantly altered metabolite peaks were detected. As a result, ZPT caused altered perturbation of metabolic pathways in male and female zebrafish liver. Moreover, ZPT induced the liver injury with the changes of the metabolites 2,4-diaminobutyric acid (2,4-DABA) with significant distinction between male and female zebrafish. ZPT caused gender-differentiated liver metabolic changes associated with the disruption of glycogenolysis and glycolysis metabolism, purine and pyrimidine metabolism, oxidative phosphorylation, arginine biosynthesis, and amino acid metabolism. Conclusively, exposure of ZPT may result in gender-differentiated metabolic abnormalities of adult zebrafish with induced hepatotoxicity.

The photodynamic and direct actions of methylene blue on mitochondrial energy metabolism: A balance of the useful and harmful effects of this photosensitizer

According to the literature, methylene blue (MB) is a photosensitizer (PS) with a high affinity for mitochondria. Therefore, several studies have explored this feature to evaluate its photodynamic effects on the mitochondrial apoptotic pathway under normoxic conditions. We are aware only of limited reports regarding MB's photodynamic effects on mitochondrial energy metabolism, especially under hypoxic conditions. Thus, the purposes of this study were to determine the direct and photodynamic acute effects of MB on the energy metabolism of rat liver mitochondria under hypoxic conditions and its direct acute effects on several parameters linked to energy metabolism in the isolated perfused rat liver. MB presented a high affinity for mitochondria, irrespective of photostimulation or proton gradient formation. Upon photostimulation, MB demonstrated high in vitro oxidizing species generation ability. Consequently, MB damaged the mitochondrial macromolecules, as could be evidenced by the elevated levels of lipid peroxidation and protein carbonyls. In addition to generating a pro-oxidant environment, MB also led to a deficient antioxidant defence system, as indicated by the reduced glutathione (GSH) depletion. Bioenergetically, MB caused uncoupling of oxidative phosphorylation and led to photodynamic inactivation of complex I, complex II, and F1FO–ATP synthase complex, thus decreasing mitochondrial ATP generation. Contrary to what is expected for an ideal PS, MB displayed appreciable dark toxicity on mitochondrial energy metabolism. The results indicated that MB acted via at least three mechanisms: direct damage to the inner mitochondrial membrane; uncoupling of oxidative phosphorylation; and inhibition of electron transfer. Confirming the impairment of mitochondrial energy metabolism, MB also strongly inhibited mitochondrial ATP production. In the perfused rat liver, MB stimulated oxygen consumption, decreased the ATP/ADP ratio, inhibited gluconeogenesis and ureogenesis, and stimulated glycogenolysis, glycolysis, and ammoniagenesis, fully corroborating its uncoupling action in intact cells, as well. It can be concluded that even under hypoxic conditions, MB is a PS with potential for photodynamic effect-induced mitochondrial dysfunction. However, MB disrupts the mitochondrial energy metabolism even in the dark, causing energy-linked liver metabolic changes that could be harmful in specific circumstances.

Metabolomic Analysis of the Liver of a Dextran Sodium Sulfate-Induced Acute Colitis Mouse Model: Implications of the Gut-Liver Connection.

The incidence of ulcerative colitis (UC) is increasing worldwide, and it has become a growing problem in Asia. Previous research on UC has focused on serum, plasma, urine, gut tissues, and fecal metabolic profiling, but a comprehensive investigation into the correlation between the severity of colitis and changes in liver metabolism is still lacking. Since the liver and gut exchange nutrients and metabolites through a complex network, intestinal diseases can affect both the liver and other organs. In the present study, concentration-dependent dextran sodium sulfate (DSS)-induced ulcerative colitis was employed to examine changes in liver metabolism using a proton nuclear magnetic resonance spectroscopy (1H-NMR)-and ultra-performance liquid chromatography time of flight mass spectroscopy (UPLC-TOF MS)-based metabolomics study. Using the multivariate statistical analysis method orthogonal projections to latent structures discriminant analysis (OPLS-DA), changes in metabolites depending on the DSS dose could be clearly distinguished. Specifically, hepatic metabolites involved in one-carbon metabolism, carnitine-related metabolism, and nucleotide synthesis were found to be affected by intestinal inflammation, implying the existence of a metabolic connection between the gut and liver. We are currently investigating the significance of this metabolic condition in UC.

Evaluation of metabolic changes in liver and serum of streptozotocin-induced diabetic rats after Mango diet supplementation

Abstract Mango consumption has shown bioactive properties against several diseases like diabetes, therefore, we evaluated how a mango-supplemented diet affects metabolic pathways in diabetic rats. Serum and liver samples were collected from 26 rats divided into 3 groups (healthy, untreated diabetic and mango-treated diabetic) after dietary intervention and analysed using an LC-MS untargeted metabolomic strategy. Twenty-six and 29 metabolites in serum and liver were potentially annotated, showing significant differences among groups. Several affected pathways were due to the disease state [fatty acids (i.e. palmitoleic, linolenic, stearidonic, eicosapentaenoic, docosahexaenoic acids and others), bile acids (i.e. glycocholic acid) and amino acids (i.e. leucine, isoleucine and valine)], and others due to mango supplementation (increased hepatic bioaccumulation of euxanthone, a mangiferin metabolite, and increased glutathione concentration). These results suggest that a mango-supplemented diet exerted a significant antioxidant effect in the liver of diabetic rats, likely due to its phenolic compounds, like mangiferin and its metabolites.

Prebiotic Effect of Lycopene and Dark Chocolate on Gut Microbiome with Systemic Changes in Liver Metabolism, Skeletal Muscles and Skin in Moderately Obese Persons.

Lycopene rich food and dark chocolate are among the best-documented products with a broad health benefit. This study explored the systemic effect of lycopene and dark chocolate (DC) on gut microbiota, blood, liver metabolism, skeletal muscle tissue oxygenation and skin. 30 volunteers were recruited for this trial, 15 women and 15 men with a mean age of 55 ± 5.7 years and with moderate obesity, 30 < BMI < 35 kg/m2. They were randomized and divided into five equal interventional groups: three received different formulations of lycopene, one of them with a 7 mg daily dose and two with 30 mg; another group was given 10 g of DC with 7 mg lycopene embedded into its matrix, and the last group received 10 g DC. The trial was double-blinded for the three lycopene groups and separately for the 2 DC groups; the trial lasted for 1 month. By the end of the trial there were dose-dependent changes in the gut microbiota profile in all three lycopene groups with an increase of relative abundance of, e.g., Bifidobacterium adolescentis and Bifidobacterium longum. This was also accompanied by dose-dependent changes in the blood, liver metabolism, skeletal muscle and skin parameters. Consumption of DC resulted in increased relative abundance of, e.g., Lactobacillus and a reduction of corneocyte exfoliation. This is the first study which reports the prebiotic potential of lycopene and DC.

Associations between Aerobic Capacity, Hepatic Bile Acid Synthesis and Fecal Bile Acid Concentration in Humans

High aerobic capacity protects against a wide range of metabolic diseases and associates with changes in liver metabolism including enhanced mitochondrial function, although mechanisms remain unknown. Bile acids are now seen as active players in metabolic regulation. We have previously found that rodents with high aerobic capacity potentially have the ability to divert excess acetyl‐CoA away from de novo lipogenesis and toward bile acid synthesis and fecal excretion. To determine if the fitness‐bile acid association manifests in humans, in a preliminary study we tested the hypothesis that female subjects screened for high aerobic fitness (Hi‐Fit, n=10) (VO2peak&gt;45 ml/kg/min) also have increased hepatic bile acid synthesis and fecal excretion compared to those matched for age and body mass with low aerobic fitness (Lo‐Fit, n=10) (VO2peak&lt;35 ml/kg/min). Diet intake, activity level, stool, and blood were measured at baseline before receiving a 1 week standardized, weight‐maintaining eucaloric diet. After the 1week standardized diet, stool and blood were again measured, and an Oral Glucose Tolerance Test (OGTT) was performed. Hi‐fit women tended to have higher bile acid synthesis via measured serum 7α‐hydroxy‐4‐cholesten‐3‐one (C4), a clinically proven surrogate of bile acid production, both during fasting (p≈0.16) and following the OGTT (p≈0.06). However, no significant differences in circulating or fecal bile acid concentrations were found. Future research should consider using direct tracer measurements of bile acid synthesis and excretion, and the utilization of 24 hr+ fecal bile acid measures to quantify total production and excretion.Support or Funding InformationUSDA‐Agricultural Research Service Project 6026‐51000‐010‐05SThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Rapamycin administration is not a valid therapeutic strategy for every case of mitochondrial disease.

BackgroundThe vast majority of mitochondrial disorders have limited the clinical management to palliative care. Rapamycin has emerged as a potential therapeutic drug for mitochondrial diseases since it has shown therapeutic benefits in a few mouse models of mitochondrial disorders. However, the underlying therapeutic mechanism is unclear, the minimal effective dose needs to be defined and whether this therapy can be generally used is unknown.MethodsWe have evaluated whether low and high doses of rapamycin administration may result in therapeutic effects in a mouse model (Coq9R239X) of mitochondrial encephalopathy due to CoQ deficiency. The evaluation involved phenotypic, molecular, image (histopathology and MRI), metabolomics, transcriptomics and bioenergetics analyses.FindingsLow dose of rapamycin induces metabolic changes in liver and transcriptomics modifications in midbrain. The high dose of rapamycin induces further changes in the transcriptomics profile in midbrain due to the general inhibition of mTORC1. However, neither low nor high dose of rapamycin were able to improve the mitochondrial bioenergetics, the brain injuries and the phenotypic characteristics of Coq9R239X mice, resulting in the lack of efficacy for increasing the survival.InterpretationThese results may be due to the lack of microgliosis-derived neuroinflammation, the limitation to induce autophagy, or the need of a functional CoQ-junction. Therefore, the translation of rapamycin therapy into the clinic for patients with mitochondrial disorders requires, at least, the consideration of the particularities of each mitochondrial disease.FundSupported by the grants from “Fundación Isabel Gemio - Federación Española de Enfermedades Neuromusculares – Federación FEDER” (TSR-1), the NIH (P01HD080642) and the ERC (Stg-337327).

The timing of docetaxel initiation in metastatic castrate-sensitive prostate cancer and the rate of chemotherapy-induced toxicity.

Docetaxel pharmacokinetics are affected by androgen deprivation therapy (ADT), which is attributed to changes in liver metabolism induced by castration. In this retrospective analysis, we assessed whether initiating docetaxel treatment in close proximity to the start of ADT therapy for metastatic castrate-sensitive prostate cancer (mCSPC) is associated with more treatment-related toxicity. We identified all patients with mCSPC treated at The Ottawa Hospital that received docetaxel chemotherapy between June 2014 and September 2017. For each patient, we calculated the time to chemotherapy (TTC) interval between the start of ADT and the first cycle of docetaxel. We checked for an association between TTC and febrile neutropenia (FN), toxicity-induced dose reduction, toxicity-induced treatment delay, and toxicity-induced treatment discontinuation. Eighty-three patients were identified. The median TTC was 67 days (range 3-189). Twenty-three patients (27.7%) experienced FN. Docetaxel toxicity resulted in 8 patients (9.6%) having their treatment delayed, 30 patients (36.1%) having their dose reduced and 18 (21.6%) having their treatment discontinued before completing the scheduled 6 cycles. No correlation was found between the TTC and FN (P = 0.99), docetaxel dose reduction (P = 0.95), treatment delay (P = 0.06), and treatment discontinuation (P = 0.88). The timing of docetaxel treatment initiation in relation to ADT initiation in patients with mCSPC did not affect the rate of treatment-related toxicity. Therefore, there is no indication for upfront chemotherapy delay from start of ADT unless clinical factors warrant a delay in starting chemotherapy. A higher than expected FN rate was identified, and primary prophylaxis should be considered.

Pre-pubertal exposure to high temperature impairs ovarian and adrenal gland function in female rats.

The influence of different levels of heat exposure on the functions of ovarian and adrenal gland were investigated in pre-puberty female rats. Three-week old female rats were treated with control (26°C) or three higher temperatures (38, 40 and 42°C) for 2hr/day. After 9 days of treatment, blood samples were collected for measurement of luteinizing hormone (LH), follicle stimulating hormone (FSH), estradiol-17β, corticosterone, cholesterol and triglyceride. Adrenal glands, ovaries and liver were collected for analyzing gene expressions. Body and liver weight were significantly low in the 42°C heating group. Circulating LH and triglyceride in the 42°C heating group were significantly lower, and estradiol-17β, corticosterone and cholesterol were significantly higher than those of the control group. The gene expression of 3β-HSD and P450c21 in the adrenal gland; 3β-HSD, receptors of LH, FSH and estrogen in the ovary were significantly low in heated rats. The liver gene expressions of caspase 3 and NK-κB were significantly high in 42°C heated rats, suggesting that the ability of liver metabolic function reduced in the 42°C heated rats. These results demonstrated that the high temperature is responsible for suppression of ovarian function by decreasing the expression of steroidogenic enzymes, estrogen and gonadotropin receptors in the ovary. Increase in circulating estradiol-17β in the heated rats may be due to accumulate this hormone in circulation by potential changes in liver metabolism during the heat stress.

Metabolomics Reveals Metabolic Changes Caused by Low-Dose 4-Tert-Octylphenol in Mice Liver.

Background: Humans are constantly exposed to low concentrations of 4-tert-octylphenol (OP). However, studies investigating the effects of low-dose OP on the liver are scarce, and the mechanism of these effects has not been thoroughly elucidated to date. Methods: Adult male institute of cancer research (ICR) mice were exposed to low-dose OP (0, 0.01 and 1 μg/kg/day) for 7 consecutive days. Weights of mice were recorded daily during the experiment. Blood serum levels of OP, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined, and haematoxylin-eosin (HE) staining of the liver was performed. We applied an integrated metabolomic and enzyme gene expression analysis to investigate liver metabolic changes, and the gene expression of related metabolic enzymes was determined by real-time PCR and ELISA. Results: OP in blood serum was increased after OP exposure, while body weights of mice were unchanged. Liver weight and its organ coefficient were decreased significantly in the OP (1 μg/kg/day) group, but ALT and AST, as well as the HE staining results, were unchanged after OP treatment. The levels of cytidine, uridine, purine and N-acetylglutamine were increased significantly, and the level of vitamin B6 was decreased significantly in mice treated with OP (1 μg/kg/day). The mRNA and protein levels of Cda and Shmt1 were both increased significantly in OP (1 μg/kg/day)-treated mice. Conclusions: Through metabolomic analysis, our study firstly found that pyrimidine and purine synthesis were promoted and that N-acetylglutamine was upregulated after low-dose OP treatment, indicating that the treatment disturbed nucleic acid and amino acid metabolism in mice liver.

Differential Role of Hypothalamic AMPKα Isoforms in Fish: an Evolutive Perspective.

In mammals, hypothalamic AMP-activated protein kinase (AMPK) α1 and α2 isoforms mainly relate to regulation of thermogenesis/liver metabolism and food intake, respectively. Since both isoforms are present in fish, which do not thermoregulate, we assessed their role(s) in hypothalamus regarding control of food intake and energy homeostasis. Since many fish species are carnivorous and mostly mammals are omnivorous, assessing if the role of hypothalamic AMPK is different is also an open question. Using the rainbow trout as a fish model, we first observed that food deprivation for 5days did not significantly increase phosphorylation status of AMPKα in hypothalamus. Then, we administered adenoviral vectors that express dominant negative (DN) AMPKα1 or AMPKα2 isoforms. The inhibition of AMPKα2 (but not AMPKα1) led to decreased food intake. The central inhibition of AMPKα2 resulted in liver with decreased capacity of use and synthesis of glucose, lipids, and amino acids suggesting that a signal of nutrient abundance flows from hypothalamus to the liver, thus suggesting a role for central AMPKα2 in the regulation of peripheral metabolism in fishes. The central inhibition of AMPKα1 induced comparable changes in liver metabolism though at a lower extent. From an evolutionary point of view, it is of interest that the function of central AMPKα2 remained similar throughout the vertebrate lineage. In contrast, the function of central AMPKα1 in fish relates to modulation of liver metabolism whereas in mammals modulates not only liver metabolism but also brown adipose tissue and thermogenesis.

Untargeted serum metabolomics of hepatocellular carcinoma in a prospective cohort of European populations

Introduction Hepatocellular carcinoma (HCC) is characterised by increasing incidence, late diagnosis and high mortality rates. Changes in liver metabolism during HCC development may alter circulating metabolite levels, which could be identified years before HCC diagnosis. Also, a detailed understanding of metabolic dysfunction in HCC may lead to the identification of better prevention strategies. In this context, we aimed to characterise pre-diagnostic circulating biomarkers of HCC risk using an LC-MS untargeted metabolomics approach. Methods A nested case-control study was conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort of > 520,000 participants from 10 European countries. Extensive metabolic profiling was conducted using liquid chromatography-mass spectrometry (LC-MS) and compared between serum samples of 129 HCC cases and their 1:1 matched controls. Multivariable univariate conditional logistic regression models adjusted for anthropometric factors, physical activity, alcohol intake, smoking status and education were used to estimate HCC risk associated with each biomarker and calculated as odds ratios (OR) per 1 standard deviation of log-transformed value. Results Out of 9206 detected metabolic features, 220 significantly discriminated HCC cases from controls after Benjamini-Hochberg correction for multiple testing. Among 37 key compounds that were annotated, 14 were identified with high confidence using authentic chemical standards. Among those, retinol, dehydroepiandrosterone sulfate, glycerophosphocholine, γ-carboxyethylhydroxychroman and creatine were inversely associated with HCC risk (ORs ranging from 0.27 to 0.56). Nine metabolites exhibited positive associations (OR = 6.78 to 2.04): 7-methylguanine, glycocholic acid, glycocheno-deoxycholic acid, L,L-cyclo(leucyl-prolyl), sphingosine, p-hydroxyphenyllactic acid, isatin, N1-acetylspermidine and tyrosine. The remaining 23 annotated metabolites were mainly represented by phospoholipids (mostly inverse associations) and two bilirubin metabolites (positive associations). Conclusions Our findings indicate that dietary factors, altered cholesterol and phospholipid metabolism, DNA damage, and gut bacterial metabolism appear to be involved in HCC development. If validated, these profile changes may be explored as markers of early HCC diagnosis.

Increased butyrate priming in the gut stalls microbiome associated-gastrointestinal inflammation and hepatic metabolic reprogramming in a mouse model of Gulf War Illness

Most of the associated pathologies in Gulf War Illness (GWI) have been ascribed to chemical and pharmaceutical exposures during the war. Since an increased number of veterans complain of gastrointestinal (GI), neuroinflammatory and metabolic complications as they age and there are limited options for a cure, the present study was focused to assess the role of butyrate, a short chain fatty acid for attenuating GWI-associated GI and metabolic complications. Results in a GWI-mouse model of permethrin and pyridostigmine bromide (PB) exposure showed that oral butyrate restored gut homeostasis and increased GPR109A receptor copies in the small intestine (SI). Claudin-2, a protein shown to be upregulated in conditions of leaky gut was significantly decreased following butyrate administration. Butyrate decreased TLR4 and TLR5 expressions in the liver concomitant to a decrease in TLR4 activation. GW-chemical exposure showed no clinical signs of liver disease but a significant alteration of metabolic markers such as SREBP1c, PPAR-α, and PFK was evident. Liver markers for lipogenesis and carbohydrate metabolism that were significantly upregulated following GW chemical exposure were attenuated by butyrate priming in vivo and in human primary hepatocytes. Further, Glucose transporter Glut-4 that was shown to be elevated following liver complications were significantly decreased in these mice after butyrate administration. Finally, use of TLR4 KO mice completely attenuated the liver metabolic changes suggesting the central role of these receptors in the GWI pathology. In conclusion, we report a butyrate specific mechanistic approach to identify and treat increased metabolic abnormalities in GWI veterans with systemic inflammation, chronic fatigue, GI disturbances, metabolic complications and weight gain.

Non-invasive detection of divergent metabolic signals in insulin deficiency vs. insulin resistance in\xa0vivo

The type 2 diabetic phenotype results from mixed effects of insulin deficiency and insulin resistance, but the relative contributions of these two distinct factors remain poorly characterized, as do the respective roles of the gluconeogenic organs. The purpose of this study was to investigate localized in vivo metabolic changes in liver and kidneys of contrasting models of diabetes mellitus (DM): streptozotocin (STZ)-treated wild-type Zucker rats (T1DM) and Zucker diabetic fatty (ZDF) rats (T2DM). Intermediary metabolism was probed using hyperpolarized (HP) [1-13C]pyruvate MRI of the liver and kidneys. These data were correlated with gene expression data for key mediators, assessed using rtPCR. Increased HP [1-13C]lactate was detected in both models, in association with elevated gluconeogenesis as reflected by increased expression of phosphoenolpyruvate carboxykinase. In contrast, HP [1-13C]alanine diverged between the two models, increasing in ZDF rats, while decreasing in the STZ-treated rats. The differences in liver alanine paralleled differences in key lipogenic mediators. Thus, HP [1-13C]alanine is a marker that can identify phenotypic differences in kidneys and liver of rats with T1DM vs. T2DM, non-invasively in vivo. This approach could provide a powerful diagnostic tool for characterizing tissue metabolic defects and responses to treatment in diabetic patients with ambiguous systemic manifestations.

Metabolite identification in fecal microbiota transplantation mouse livers and combined proteomics with chronic unpredictive mild stress mouse livers

Major depressive disorder (MDD) is a common mood disorder. Gut microbiota may be involved in the pathogenesis of depression via the microbe–gut–brain axis. Liver is vulnerable to exposure of bacterial products translocated from the gut via the portal vein and may be involved in the axis. In this study, germ-free mice underwent fecal microbiota transplantation from MDD patients and healthy controls. Behavioral tests verified the depression model. Metabolomics using gas chromatography–mass spectrometry, nuclear magnetic resonance, and liquid chromatography–mass spectrometry determined the influence of microbes on liver metabolism. With multivariate statistical analysis, 191 metabolites were distinguishable in MDD mice from control (CON) mice. Compared with CON mice, MDD mice showed lower levels for 106 metabolites and higher levels for 85 metabolites. These metabolites are associated with lipid and energy metabolism and oxidative stress. Combined analyses of significantly changed proteins in livers from another depression model induced by chronic unpredictive mild stress returned a high score for the Lipid Metabolism, Free Radical Scavenging, and Molecule Transports network, and canonical pathways were involved in energy metabolism and tryptophan degradation. The two mouse models of depression suggest that changes in liver metabolism might be involved in the pathogenesis of MDD. Conjoint analyses of fecal, serum, liver, and hippocampal metabolites from fecal microbiota transplantation mice suggested that aminoacyl-tRNA biosynthesis significantly changed and fecal metabolites showed a close relationship with the liver. These findings may help determine the biological mechanisms of depression and provide evidence about “depression microbes” impacting on liver metabolism.

8-oxoguanine DNA glycosylase (Ogg1) controls hepatic gluconeogenesis

Mitochondrial DNA (mtDNA) resides in close proximity to metabolic reactions, and is maintained by the 8-oxoguanine DNA glycosylase (Ogg1) and other members of the base excision repair pathway. Here, we tested the hypothesis that changes in liver metabolism as under fasting/feeding conditions would be sensed by liver mtDNA, and that Ogg1 deficient mice might unravel a metabolic phenotype. Wild type (WT) and ogg1−/− mice were either fed ad libitum or subjected to fasting for 24h, and the corresponding effects on liver gene expression, DNA damage, as well as serum values were analyzed. Ogg1 deficient mice fed ad libitum exhibited hyperglycemia, elevated insulin levels and higher liver glycogen content as well as increased accumulation of 8oxoG in mtDNA compared to age- and gender matched WT mice. Interestingly, these phenotypes were absent in ogg1−/− mice during fasting. Gene expression and functional analyses suggest that the diabetogenic phenotype in the ogg1−/− mice is due to a failure to suppress gluconeogensis in the fed state. The ogg1−/− mice exhibited reduced mitochondrial electron transport chain (ETC) capacity and a combined low activity of the pyruvate dehydrogenase (PDH), alluding to inefficient channeling of glycolytic products into the citric acid cycle. Our data demonstrate a physiological role of base excision repair that goes beyond DNA maintenance, and implies that DNA repair is involved in regulating metabolism.

Xanthohumol Restores Hepatic Glucolipid Metabolism Balance in Type 1 Diabetic Wistar Rats.

Diabetes exhibits increased inflammation, angiogenesis, and apoptosis, three processes attenuated by xanthohumol (XN). Herein, we evaluate the effect of XN-enriched stout beer consumption in hepatic glucolipid metabolism imbalance seen in type 1 diabetes (T1D). Five groups of Wistar rats were established: streptozotocin-induced diabetic rats drinking water, treated with 5% ethanol, stout beer, and stout beer supplemented with 10 mg of XN/L and healthy rats drinking water. Hepatic periodic acid-Schiff, reticulin, sirius red, and oil red O histological staining was performed. Lipogenic enzymes and glucose transporter 2 (GLUT2) expression was evaluated by western blotting. Increased fibrosis in T1D animals was significantly decreased to control levels by XN (3.85 ± 0.38 in T1D-beer versus 1.78 ± 0.27 in controls, p < 0.05; 2.27 ± 0.69 in T1D-beer + XN versus 1.78 ± 0.27 in controls, p > 0.05). XN reduced T1D hepatic reticulin staining (9.74 ± 3.78 in T1D-beer, p < 0.05 versus control) to healthy levels (4.45 ± 1.05 in T1D-beer + XN versus 4.60 ± 0.20 in healthy controls, p > 0.05). XN consumption interfered with the T1D liver catabolic state, reversing glycogen depletion (22.09 ± 7.70 in T1D-beer + XN versus 4.68 ± 4.84 in T1D-beer, p < 0.05) and GLUT2 upregulation (1.71 ± 0.46 in T1D-beer + XN versus 2.13 ± 0.34 in T1D-beer, p < 0.05) and enhancing lipogenesis (1.19 ± 0.11 in T1D-beer + XN versus 1.96 ± 0.36 in T1D, p < 0.05 for acetyl-CoA carboxylase; 1.10 ± 0.04 in T1D-beer + XN versus 0.44 ± 0.31 in T1D, p < 0.05 for fatty acid synthase). These findings reveal that XN can be a therapeutic agent against liver metabolic changes in T1D, playing a possible role in the insulin receptor pathways.

Abstract 2510: Interrogating liver metabolic stress due to cancer-induced cachexia

Abstract Cancer-induced cachexia accounts for approximately 20% of all cancer deaths 1. In pancreatic cancer, the syndrome affects nearly 80% of patients 2,3. Cachectic patients experience a wide range of symptoms affecting the function of several organs such as muscle, liver, brain, and heart, that decrease quality of life and worsen prognosis. A major characteristic of cachexia is the accelerated skeletal muscle and fat storage wasting causing nutrient mobilization both directly as lipid and amino acids, and indirectly as glucose derived from the exploitation of liver gluconeogenesis that reaches the tumor through the bloodstream4. Patients with cachexia develop a wide range of metabolic stress from increased proteins and fat tissue burning resulting in increased energy expenditure. Here, for the first time, we have performed high-resolution quantitative 1H magnetic resonance spectroscopy (MRS) of liver tissue obtained from normal, noncachectic and cachectic mice bearing PDAC that are cachectic (Pa04C) and noncachectic (Panc1). A significant reduction in liver weight and significant changes in 1H MRS derived metabolite profiles were detected with cachexia. Human pancreatic cancer cell lines, Panc1 and Pa04C, were used for the study. Six to 8 week old male severe combined immunodeficient mice were inoculated in the right flank with cancer cells (5×106) and in the right hind leg muscle with reporter myoblasts (2×106) to monitor the development of cachexia in mice5. Live animal optical imaging was done using a Xenogen IVIS® Spectrum (PerkinElmer) optical scanner. Dual phase solvent extraction was performed on liver tissue to extract water soluble metabolites. All 1H MR spectra were acquired on an Avance 750 MHz Bruker NMR spectrometer. We found, for the first time, that the liver in Pa04C tumor bearing mice underwent a profound weight loss; although Panc1 tumor bearing mice showed some liver weight loss this was not as profound as observed with Pa04C tumors. Significant decreases in lactate, glucose and glutathione were observed in cachectic mouse liver compared to noncachectic mouse liver, and the liver from healthy control mice. The significant decrease of these metabolites in cachectic livers may reflect increased utilization of glucose, lactate and glutathione by the tumor or other organs during the cachexia cascade4. These results provide new insights into changes in liver metabolism during cachexia, and support investigating metabolic strategies such as supplementing glutathione or glucose to reduce cachexia associated morbidity.