[Show abstract][Hide abstract] ABSTRACT: Clinical and animal studies demonstrated that orally administered berberine had a distinct lipid-lowering effect. However, pharmacokinetic studies showed that berberine was poorly absorbed into the body so the levels of berberine in the blood and target tissues were far below the effective concentrations revealed. To probe the underlying mechanism, the effect of berberine on the biological system was studied on a high-fat-diet-induced hamster hyperlipidemia model. Our results showed that intragastrically-administered berberine was poorly absorbed into circulation and most berberine accumulated in gut content. Although the bioavailability of intragastrically administered berberine was much lower than that of intraperitoneally administered berberine, it had a stronger lipid-lowing effect, indicating that the gastrointestinal tract is a potential target for the hypolipidemic effect of berberine. A metabolomic study on both serum and gut content showed that orally administered berberine significantly regulated molecules involved in lipid metabolism, and increased the generation of bile acids in the hyperlipidemic model. DNA analysis revealed that the orally administered berberine modulated the gut microbiota, and berberine showed a significant inhibition of the 7α-dehydroxylation conversion of cholic acid to deoxycholic acid, indicating a decreased elimination of bile acids in the gut. However, in model hamsters, elevated bile acids failed to downregulate the expression and function of CYP7A1 in a negative feedback loop. It was suggested that the hypocholesterolemic effect of orally administered berberine involves modulating the turnover of bile acids and the farnesoid X receptor signal pathway.
[Show abstract][Hide abstract] ABSTRACT: For orally administered drugs, the metabolism of a drug by the gut flora plays an important role in the bioavailability, activation and disposition of the drug in vivo. However, no in vitro system is currently available to evaluate the metabolism of a drug by the gut flora before the drug is absorbed into the body. This paper presents an in vitro metabolic system in an anaerobic environment that could be used to evaluate the metabolism of an endogenous compound, cholic acid, and a xenobiotic compound, ginsenoside Rg3. We showed that the proliferation of the anaerobic bacteria of the gut content of hamsters produced a similar composition of gut flora in a culture medium for yeast to that in vivo. Incubation of ginsenoside Rg3 and cholic acid in the anaerobic in vitro system efficiently produced the metabolites Rh2 and deoxycholic acid, respectively, similar to those seen in the gut content in vivo. In comparison with in vivo analysis, this anaerobic in vitro metabolic system is convenient, reproducible, economic and animal saving, and can easily be applied to assess the transformation and disposition of a drug before it enters into the circulatory system.
European Journal of Drug Metabolism and Pharmacokinetics 06/2013; · 1.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: HIV protease inhibitors (PI) are core components of Highly Active Antiretroviral Therapy (HAART), the most effective treatment for HIV infection currently available. However, HIV PIs have now been linked to lipodystrophy and dyslipidemia, which are major risk factors for cardiovascular disease and metabolic syndrome. Our previous studies have shown that HIV PIs activate endoplasmic reticulum (ER) stress and disrupt lipid metabolism in hepatocytes and macrophages. Yet, little is known on how HIV PIs disrupt lipid metabolism in adipocytes, a major cell type involved in the pathogenesis of metabolic syndrome.
Cultured and primary mouse adipocytes and human adipocytes were used to examine the effect of frequently used HIV PIs in the clinic, lopinavir/ritonavir, on adipocyte differentiation and further identify the underlying molecular mechanism of HIV PI-induced dysregulation of lipid metabolism in adipocytes. The results indicated that lopinavir alone or in combination with ritonavir, significantly activated the ER stress response, inhibited cell differentiation, and induced cell apoptosis in adipocytes. In addition, HIV PI-induced ER stress was closely linked to inhibition of autophagy activity. We also identified through the use of primary adipocytes of CHOP(-/-) mice that CHOP, the major transcriptional factor of the ER stress signaling pathway, is involved in lopinavir/ritonavir-induced inhibition of cell differentiation in adipocytes. In addition, lopinavir/ritonavir-induced ER stress appears to be associated with inhibition of autophagy activity in adipocytes.
Activation of ER stress and impairment of autophagy activity are involved in HIV PI-induced dysregulation of lipid metabolism in adipocytes. The key components of ER stress and autophagy signaling pathways are potential therapeutic targets for HIV PI-induced metabolic side effects in HIV patients.
PLoS ONE 03/2013; 8(3):e59514. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Early diagnosis of diabetic nephropathy (DN) is difficult although it is of crucial importance to prevent its development. To probe potential markers and the underlying mechanism of DN, an animal model of DN, the db/db mice, were used and serum and urine metabolites were profiled using gas chromatography time of flight mass spectrometry. Metabolic patterns were evaluated based on serum and urine data. Principal component analysis of the data revealed obvious metabonomic difference between db/db mice and controls, and db/db mice showed distinctly different metabolic patterns during the progression from diabetes to early, medium and later DN. The identified metabolites discriminating between db/db mice and controls suggested that db/db mice have perturbations in the tricarboxylic acid cycle (TCA, citrate, malate, succinate, aconitate), lipid metabolism, glycolysis, and amino acid turnover. The db/db mice were characterized by acidic urine, high TCA intermediates in serum at week 6 and a sharp decline thereafter, and gradual elevation of free fatty acids in the serum. The sharp drop of serum TCA intermediates from week 6 to 8 indicated the down-regulated glycolysis and insulin resistance. However, urinary TCA intermediates did not decrease in parallel with those in the serum from week 6 to 10; and an increased portion of TCA intermediates in the serum was excreted into the urine at 8, 10, 12 weeks than at 6 weeks, indicating kidney dysfunction occurred. The relative abundances of TCA intermediates in urine relative to those in serum were suggested as an index of renal damage.
[Show abstract][Hide abstract] ABSTRACT: Continuous exposure of breast cancer cells to adriamycin induces high expression of P-gp and multiple drug resistance. However, the biochemical process and the underlying mechanisms for the gradually induced resistance are not clear. To explore the underlying mechanism and evaluate the anti-tumor effect and resistance of adriamycin, the drug-sensitive MCF-7S and the drug-resistant MCF-7Adr breast cancer cells were used and treated with adriamycin, and the intracellular metabolites were profiled using gas chromatography mass spectrometry. Principal components analysis of the data revealed that the two cell lines showed distinctly different metabolic responses to adriamycin. Adriamycin exposure significantly altered metabolic pattern of MCF-7S cells, which gradually became similar to the pattern of MCF-7Adr, indicating that metabolic shifts were involved in adriamycin resistance. Many intracellular metabolites involved in various metabolic pathways were significantly modulated by adriamycin treatment in the drug-sensitive MCF-7S cells, but were much less affected in the drug-resistant MCF-7Adr cells. Adriamycin treatment markedly depressed the biosynthesis of proteins, purines, pyrimidines and glutathione, and glycolysis, while it enhanced glycerol metabolism of MCF-7S cells. The elevated glycerol metabolism and down-regulated glutathione biosynthesis suggested an increased reactive oxygen species (ROS) generation and a weakened ability to balance ROS, respectively. Further studies revealed that adriamycin increased ROS and up-regulated P-gp in MCF-7S cells, which could be reversed by N-acetylcysteine treatment. It is suggested that adriamycin resistance is involved in slowed metabolism and aggravated oxidative stress. Assessment of cellular metabolomics and metabolic markers may be used to evaluate anti-tumor effects and to screen for candidate anti-tumor agents.
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: HIV protease inhibitor (PI)-induced inflammatory response in macrophages is a major risk factor for cardiovascular diseases. We have previously reported that berberine (BBR), a traditional herbal medicine, prevents HIV PI-induced inflammatory response through inhibiting endoplasmic reticulum (ER) stress in macrophages. We also found that HIV PIs significantly increased the intracellular concentrations of BBR in macrophages. However, the underlying mechanisms of HIV PI-induced BBR accumulation are unknown. This study examined the role of P-glycoprotein (P-gp) in HIV PI-mediated accumulation of BBR in macrophages. METHODOLOGY AND PRINCIPAL FINDINGS: Cultured mouse RAW264.7 macrophages, human THP-1-derived macrophages, Wild type MDCK (MDCK/WT) and human P-gp transfected (MDCK/P-gp) cells were used in this study. The intracellular concentration of BBR was determined by HPLC. The activity of P-gp was assessed by measuring digoxin and rhodamine 123 (Rh123) efflux. The interaction between P-gp and BBR or HIV PIs was predicated by Glide docking using Schrodinger program. The results indicate that P-gp contributed to the efflux of BBR in macrophages. HIV PIs significantly increased BBR concentrations in macrophages; however, BBR did not alter cellular HIV PI concentrations. Although HIV PIs did not affect P-gp expression, P-gp transport activities were significantly inhibited in HIV PI-treated macrophages. Furthermore, the molecular docking study suggests that both HIV PIs and BBR fit the binding pocket of P-gp, and HIV PIs may compete with BBR to bind P-gp. CONCLUSION AND SIGNIFICANCE: HIV PIs increase the concentration of BBR by modulating the transport activity of P-gp in macrophages. Understanding the cellular mechanisms of potential drug-drug interactions is critical prior to applying successful combinational therapy in the clinic.
PLoS ONE 01/2013; 8(1):e54349. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: HIV protease inhibitors (PIs) are the cornerstone of Highly Active Antiretroviral Therapy (HAART). Their antiretroviral potent is attributable to their pharmacokinetic properties. Yet, as the pharmacologic target of HIV PIs is localized within HIV-infected cells, cellular pharmacokinetic properties must also be determined to predict not only efficacy, but also toxicity. In this review, we review recent studies about cellular pharmacokinetics of current marketed HIV PIs, as well as the physicochemical properties of HIV PIs and their drug transporters and enzymes. Additionally, a summary of potential strategies for optimizing cellular pharmacokinetics of HIV PIs and initial ideas to study cellular pharmacokinetics is also discussed. Cellular pharmacokinetics of HIV PIs is an important budding field of research that will significantly influence efficacy and toxicity profiles of these essential drugs, and we hope our review will aid in fundamental knowledge for future research.
Current Drug Metabolism 06/2012; · 3.49 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Recently, there is a global trend of using herbal medicines to treat various chronic diseases and promote health. But the controversy over the safety and efficacy of herbal medicines is a focus of attention, primarily because of the many unknown and unrevealed natures of herbal medicines, which strongly restricts their application and development. Pharmacokinetics is a bridge linking the herbal medicines and their pharmacological responses. It is assumed in traditional pharmacokinetics that an excellent drug should have appropriate pharmacokinetic behaviours and its pharmacological effect is related with plasma drug concentrations. However, most herbal medicines exhibit excellent pharmacological responses despite poor pharmacokinetic behaviours. As most drugs are intracellulartargeted, we put forward cellular pharmacokinetic-pharmacodynamic strategy, which is focused on the intracellular fate of drugs. This strategy could partially explain the marked pharmacological activities of herbal medicines from their intracellular pharmacokinetic behaviours, rather than their plasma concentrations. It is a helpful complementarity to traditional pharmacokinetics, and takes a potential role in the research and development of new herb-origined drugs. In this review, the pharmacokinetics-pharmacology disconnections of herbal medicines (such as ginseng, berberine and danshen) are retrospected. Then our proposed cellular pharmacokineticpharmacodynamic strategy, its characteristics, as well as its research procedures are described, followed by the subcellular distributions of drug transporters and metabolic enzymes which are the determinants of cellular pharmacokinetics-pharmacodynamics. Finally, our successful applications of cellular pharmacokinetic-pharmacodynamic strategy in elucidating ginsenoside Rh2 as an adjuvant agent and tanshinone IIA as an anticancer agent are illustrated.
Current Drug Metabolism 03/2012; 13(5):558-76. · 3.49 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Metabolomics allows high-throughput analysis of low-molecular-weight compounds in biofluids that reflect the physiological
status and biochemical metabolism of living systems. Hence it has the potential to evaluate toxicity and clarifies the metabolism-related
toxic mechanisms. In this study a promising candidate drug parent, triptolide, was given to Sprague–Dawley rats as a model
toxicant at a single dose of 0.6, or 2.4mg/kg, i.g. Both routine biochemical assays and histopathological inspection showed
time-dependent hepatic toxicity at the higher dose, but no obvious toxicity at the lower dose. Meanwhile, serum metabolome
was profiled using the non-targeted metabolomic tool, gas chromatography time-of-flight mass spectrometry. Based on the acquired
metabolomic data, mathematical models were calculated and the metabolic patterns of serum were evaluated using projection
to latent structure-discriminant analysis. The relative distance of each treated group from the normal control was calculated
to provide a measure of toxicity. Treatment with triptolide at either the higher or lower dose caused deviations in the metabolic
pattern and resulted in perturbation of taurine, creatinine, free fatty acids, β-hydroxybutyrate, tricarboxylic acid cycle
intermediates, and amino acids. This finding indicates the dysfunction of β-oxidation of free fatty acids and impairment of
the mitochondria and confirms the hepatic toxicity of triptolide. The identified toxic markers and the calculated relative
distance values quantitatively demonstrated dose- and time-dependent toxicity, whereas the scores plot of the model provided
the qualitative information. The metabolomic approach was non-invasive and more sensitive than routine toxic assessment, and
the results of both methods correlated well.
KeywordsProjection to latent structure-discriminant analysis–Toxicity–Metabolomics–Relative distance method–Triptolide
[Show abstract][Hide abstract] ABSTRACT: Bile acids are important regulatory molecules that can activate specific nuclear receptors and cell signaling pathways in the liver and gastrointestinal tract. In the current study, the chronic bile fistula (CBF) rat model and primary rat hepatocytes (PRH) were used to study the regulation of gluconeogenic genes phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G-6-Pase) and the gene encoding short heterodimeric partner (SHP) by taurocholate (TCA). The intestinal infusion of TCA into the CBF rat rapidly (1h) activated the AKT (approximately 9-fold) and ERK1/2 (3- to 5-fold) signaling pathways, downregulated (approximately 50%, 30 min) the mRNA levels of PEPCK and G-6-Pase, and induced (14-fold in 3 h) SHP mRNA. TCA rapidly ( approximately 50%, 1-2 h) downregulated PEPCK and G-6-Pase mRNA levels in PRH. The downregulation of these genes by TCA was blocked by pretreatment of PRH with pertussis toxin (PTX). In PRH, TCA plus insulin showed a significantly stronger inhibition of glucose secretion/synthesis from lactate and pyruvate than either alone. The induction of SHP mRNA in PRH was strongly blocked by inhibition of PI3 kinase or PKCzeta by specific chemical inhibitors or knockdown of PKCzeta by siRNA encoded by a recombinant lentivirus. Activation of the insulin signaling pathway appears to be linked to the upregulation of farnesoid X receptor functional activity and SHP induction.
The Journal of Lipid Research 03/2010; 51(8):2234-44. · 4.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The development of HIV protease inhibitors (PIs) has been one of the most significant advances of the past decade in controlling HIV infection. Unfortunately, the benefits of HIV PIs are compromised by serious side effects. One of the most frequent and deleterious side effects of HIV PIs is severe gastrointestinal (GI) disorders including mucosal erosions, epithelial barrier dysfunction, and leak-flux diarrhea, which occurs in 16-62% of patients on HIV PIs. Although the underlying mechanisms behind HIV PI-associated serious adverse side effects remain to be identified, our recent studies have shown that activation of endoplasmic reticulum (ER) stress response plays a critical role in HIV PI-induced GI complications. The objective of this study was to develop a novel self-microemulsifying drug delivery system (SMEDDS) using various antioxidants as surfactants and cosurfactants to reduce the GI side effects of the most commonly used HIV PI, ritonavir. The biological activities of this SMSDDS of ritonavir were compared with that of Norvir, which is currently used in the clinic. Rat normal intestinal epithelial cells (IEC-6) and mouse Raw 264.7 macrophages were used to examine the effect of new SMEDDS of ritonavir on activation of ER stress and oxidative stress. Sprague-Dawley rats and C57/BL6 mice were used for pharmacokinetic studies and in vivo studies. The intracellular and plasma drug concentrations were determined by HPLC analysis. Activation of ER stress was detected by Western blot analysis and secreted alkaline phosphatase (SEAP) reporter assay. Reactive oxygen species (ROS) was measured using dichlorodihydrofluorescein diacetate as a probe. Cell viability was determined by Roche's cell proliferation reagent WST-1. Protein levels of inflammatory cytokines (TNF-alpha and IL-6) were determined by enzyme-linked immunosorbent assays (ELISA). The intestinal permeability was assessed by luminal enteral administration of fluorescein isothiocyanate conjugated dextran (FITC-dextran, 4 kDa). The pathologic changes in intestine were determined by histological examination. The results indicated that incorporation of antioxidants in this new SMEDDS not only significantly reduced ritonavir-induced ER stress activation, ROS production and apoptosis in intestinal epithelial cells and macrophages, but also improved the solubility, stability and bioavailability of ritonavir, and significantly reduced ritonavir-induced disruption of intestinal barrier function in vivo. In conclusion, this new SMEDDS of ritonavir has less GI side effects compared to Norvir. This new SMEDDS can be used for other HIV PIs and any insoluble antiviral drug with serious GI side effects.
[Show abstract][Hide abstract] ABSTRACT: HIV protease inhibitor (PI)-induced inflammatory response plays an important role in HIV PI-associated dyslipidemia and cardiovascular complications. This study examined the effect of berberine, a traditional herb medicine, on HIV PI-induced inflammatory response and further investigated the underlying cellular/molecular mechanisms in macrophages.
Cultured mouse J774A.1 macrophages and primary mouse macrophages were used in this study. The expression of TNF-alpha and IL-6 were detected by real-time RT-PCR and ELISA. Activations of ER stress and ERK signaling pathways were determined by Western blot analysis. Immunofluorescent staining was used to determine the intracellular localization of RNA binding protein HuR. RNA-pull down assay was used to determine the association of HuR with endogenous TNF-alpha and IL-6. Berberine significantly inhibited HIV PI-induced TNF-alpha and IL-6 expression by modulating ER stress signaling pathways and subsequent ERK activation, in turn preventing the accumulation of the RNA binding protein HuR in cytosol and inhibiting the binding of HuR to the 3'-UTRs of TNF-alpha and IL-6 in macrophages.
Inhibition of ER stress represents a key mechanism by which berberine prevents HIV PI-induced inflammatory response. Our findings provide a new insight into the molecular mechanisms of berberine and show the potential application of berberine as a complimentary therapeutic agent for HIV infection.
PLoS ONE 01/2010; 5(2):e9069. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The BCR-ABL tyrosine kinase inhibitor imatinib is highly effective for chronic myeloid leukemia (CML). However, some patients gradually develop resistance to imatinib, resulting in therapeutic failure. Metabonomic and genomic profiling of patients' responses to drug interventions can provide novel information about the in vivo metabolism of low-molecular-weight compounds and extend our insight into the mechanism of drug resistance. Based on a multi-platform of high-throughput metabonomics, SNP array analysis, karyotype and mutation, the metabolic phenotypes and genomic polymorphisms of CML patients and their diverse responses to imatinib were characterized. The untreated CML patients (UCML) showed different metabolic patterns from those of healthy controls, and the discriminatory metabolites suggested the perturbed metabolism of the urea cycle, tricarboxylic acid cycle, lipid metabolism, and amino acid turnover in UCML. After imatinib treatment, patients sensitive to imatinib (SCML) and patients resistant to imatinib (RCML) had similar metabolic phenotypes to those of healthy controls and UCML, respectively. SCML showed a significant metabolic response to imatinib, with marked restoration of the perturbed metabolism. Most of the metabolites characterizing CML were adjusted to normal levels, including the intermediates of the urea cycle and tricarboxylic acid cycle (TCA). In contrast, neither cytogenetic nor metabonomic analysis indicated any positive response to imatinib in RCML. We report for the first time the associated genetic and metabonomic responses of CML patients to imatinib and show that the perturbed in vivo metabolism of UCML is independent of imatinib treatment in resistant patients. Thus, metabonomics can potentially characterize patients' sensitivity or resistance to drug intervention.
PLoS ONE 01/2010; 5(10):e13186. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The traditional Chinese medicine concepts of "Xinxueyuzuzheng (heart blood stasis obstruction pattern)" and "Qiyinliangxuzheng (qi and yin deficiency pattern)" for myocardial ischemia rat models were constructed in the present study. Endogenous metabolites in rat plasma were analyzed using the GC/TOF-MS-based metabonomic method. Significant metabolic differences were observed between the control and two model groups, and the three groups were distinguished clearly by pattern recognition. Compared with those of the control, the levels of hydroxyproline, threonic acid, glutamine and citric acid were strikingly up- or down-regulated in model rats. The metabolites contributing most to the classification between the two "pattern" rats were identified, such as valine, serine, threonine, ornithine, hydroxyproline, lysine, 2-hydroxybutanoic acid, 3-hydroxybutanoic acid, galactofuranose and inositol. These compounds were indicated as the potential biomarkers. The results suggested that the two "patterns" are involved in dysfunction in oxidative stress, energy metabolism and amino acid metabolism. These findings also provided the substantial foundation for exploring the scientific connotation of these two "Zhengxing (pattern types)" of myocardial ischemia, and "Bianzheng (pattern identification)".
Science in China Series C Life Sciences 11/2009; 52(11):1081-90. · 1.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Human immunodeficiency virus (HIV) protease inhibitor (PI)-induced adverse effects have become a serious clinical problem. In addition to their metabolic and cardiovascular complications, these drugs also frequently cause severe gastrointestinal disorders, including mucosal erosions, epithelial barrier dysfunction, and diarrhea. However, the exact mechanisms underlying gastrointestinal adverse effects of HIV PIs remain unknown. This study investigated whether HIV PIs disrupt intestinal epithelial barrier integrity by activating endoplasmic reticulum (ER) stress.
The most commonly used HIV PIs (lopinavir, ritonavir, and amprenavir) were used; their effects on ER stress activation and epithelial paracellular permeability were examined in vitro as well as in vivo using wild-type and CHOP(-)/(-) mice.
Treatment with lopinavir and ritonavir, but not amprenavir, induced ER stress, as indicated by a decrease in secreted alkaline phosphatase activities and an increase in the unfolded protein response. This activated ER stress partially impaired the epithelial barrier integrity by promoting intestinal epithelial cell apoptosis. CHOP silencing by specific small hairpin RNA prevented lopinavir- and ritonavir-induced barrier dysfunction in cultured intestinal epithelial cells, whereas CHOP(-)/(-) mice exhibited decreased mucosal injury after exposure to lopinavir and ritonavir.
HIV PIs induce ER stress and activate the unfolded protein response in intestinal epithelial cells, thus resulting in disruption of the epithelial barrier integrity.
[Show abstract][Hide abstract] ABSTRACT: HIV protease inhibitor (PI)-associated cardiovascular risk, especially atherosclerosis, has become a major concern in the clinic. Macrophages are key players in the inflammatory response and atherosclerosis formation. We have previously shown that HIV PIs induce endoplasmic reticulum (ER) stress, activate the unfolded protein response (UPR), and increase the synthesis of the inflammatory cytokines, TNF-alpha and IL-6, by regulating the intracellular translocation of RNA binding protein HuR in macrophages. However, the underlying signaling mechanisms remain unclear. We show here that the HIV PI lopinavir significantly activated the extracellular-signal regulated protein kinase (ERK), but not c-Jun N-terminal kinase (JNK) and p38 MAPK. Lopinavir-induced cytosolic translocation of HuR and TNF-alpha and IL-6 synthesis was attenuated by specific chemical inhibitor of MEK (PD98058) or over-expression of dominant negative mutant of MEK1. In addition, we demonstrated that lopinavir-induced ERK activation and TNF-alpha and IL-6 expression were completely inhibited in macrophages from CHOP null mice. Taken together, these results indicate activation of the UPR plays an essential role in HIV PI-induced inflammatory cytokine synthesis and release by activating ERK, which increases the cytosolic translocation of HuR and subsequent binding to the 3'UTR of TNF-alpha and IL-6 mRNAs in macrophages.
[Show abstract][Hide abstract] ABSTRACT: The measurement of metabolites in tissues is of great importance in metabonomic research in the biomedical sciences, providing more relevant information than is available from systemic biofluids. The liver is the most important organ/tissue for most biochemical reactions, and the metabolites in the liver are of great interest to scientists. To develop an optimized extraction method and comprehensive profiling technique for liver metabolites, organic solvents of various compositions were designed using design of experiments to extract metabolites from the liver, and the metabolites were profiled by gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS). The resolved peak areas were processed by principle components analysis, partial least-squares projections to latent structures, and discriminant analysis. The results suggest the highest extraction efficiency was for methanol-water, which maximized the majority of GC/TOF-MS responses. The optimal solvent was applied to extract metabolites in liver of hyperlipidemia hamster and the control. The GC/TOF-MS profiles of liver metabolites showed obvious differences between hyperlipidemic hamsters and controls. A comparison of liver and serum data from the same animals identified common biomarkers and presented complementary information. Our results suggest that liver metabonomics is a valuable technique and that the combined analysis of systematic biofluids and local tissues is meaningful and complementary, recovering more comprehensive metabonomic data than either analysis alone.
[Show abstract][Hide abstract] ABSTRACT: Atherosclerosis is a complicated and multifactorial disease, induced not only by genotype, but also, even more importantly, by environmental factors. Study on the metabolic perturbation of endogenous compounds may offer deeper insight into development of atherosclerosis. Gas chromatography/mass spectrometry (GC/MS)-based metabonomics was used to profile a metabolic fingerprint of serum obtained from hamsters with induced cholesterol. The deconvoluted GC/MS data were processed by multivariate statistical analysis tools, such as principal component analysis (PCA) and partial least squares projection to latent structure and discriminant analysis (PLS-DA). For the first time we showed a time-dependent development of the model animal from normal to hypercholesterolaemia, and further to early atherosclerosis. Twenty-one compounds were identified as markers involved in the development to atherosclerosis. Identification of the compounds suggests that amino acid metabolism and fatty acid oxidation are significantly perturbed following cholesterol overloading. The data provide novel information to approach the pathophysiological processes of the hypercholesterolaemia and atherosclerosis disease continuum.