Fengjie Huang

Plasma metabolite profiles of Alzheimer's disease and mild cognitive impairment.

Previous studies have demonstrated altered metabolites in samples of Alzheimers disease (AD) patients. However, the sample size from many of them is relatively small and the metabolites are relatively limited. Here we applied a comprehensive platform using ultraperformance liquid chromatography-time-of-flight mass spectrometry and gas chromatography-time-of-flight mass spectrometry to analyze plasma samples from AD patients, amnestic mild cognitive impairment (aMCI) patients, and normal controls. A biomarker panel consisting of six plasma metabolites (arachidonic acid, N,N-dimethylglycine, thymine, glutamine, glutamic acid, and cytidine) was identified to discriminate AD patients from normal control. Another panel of five plasma metabolites (thymine, arachidonic acid, 2-aminoadipic acid, N,N-dimethylglycine, and 5,8-tetradecadienoic acid) was able to differentiate aMCI patients from control subjects. Both biomarker panels had good agreements with clinical diagnosis. The 2 panels of metabolite markers were all involved in fatty acid metabolism, one-carbon metabolism, amino acid metabolism, and nucleic acid metabolism. Additionally, no altered metabolites were found among the patients at different stages, as well as among those on anticholinesterase medication and those without anticholinesterase medication. These findings provide a comprehensive global plasma metabolite profiling and may contribute to making early diagnosis as well as understanding the pathogenic mechanism of AD and aMCI.

Branched-chain and aromatic amino acid profiles and diabetes risk in Chinese populations

Recent studies revealed strong evidence that branched-chain and aromatic amino acids (BCAAs and AAAs) are closely associated with the risk of developing type 2 diabetes in several Western countries. The aim of this study was to evaluate the potential role of BCAAs and AAAs in predicting the diabetes development in Chinese populations. The serum levels of valine, leucine, isoleucine, tyrosine, and phenylalanine were measured in a longitudinal and a cross sectional studies with a total of 429 Chinese participants at different stages of diabetes development, using an ultra-performance liquid chromatography triple quadruple mass spectrometry platform. The alterations of the five AAs in Chinese populations are well in accordance with previous reports. Early elevation of the five AAs and their combined score was closely associated with future development of diabetes, suggesting an important role of these metabolites as early markers of diabetes. On the other hand, the five AAs were not as good as existing clinical markers in differentiating diabetic patients from their healthy counterparts. Our findings verified the close correlation of BCAAs and AAAs with insulin resistance and future development of diabetes in Chinese populations and highlighted the predictive value of these markers for future development of diabetes.

Dysregulated hepatic bile acids collaboratively promote liver carcinogenesis

Dysregulated bile acids (BAs) are closely associated with liver diseases and attributed to altered gut microbiota. Here, we show that the intrahepatic retention of hydrophobic BAs including deoxycholate (DCA), taurocholate (TCA), taurochenodeoxycholate (TCDCA), and taurolithocholate (TLCA) were substantially increased in a streptozotocin and high fat diet (HFD) induced nonalcoholic steatohepatitis‐hepatocellular carcinoma (NASH‐HCC) mouse model. Additionally chronic HFD‐fed mice spontaneously developed liver tumors with significantly increased hepatic BA levels. Enhancing intestinal excretion of hydrophobic BAs in the NASH‐HCC model mice by a 2% cholestyramine feeding significantly prevented HCC development. The gut microbiota alterations were closely correlated with altered BA levels in liver and feces. HFD‐induced inflammation inhibited key BA transporters, resulting in sustained increases in intrahepatic BA concentrations. Our study also showed a significantly increased cell proliferation in BA treated normal human hepatic cell lines and a down‐regulated expression of tumor suppressor gene CEBPα in TCDCA treated HepG2 cell line, suggesting that several hydrophobic BAs may collaboratively promote liver carcinogenesis.

Metabolomics analysis reveals variation in Schisandra chinensis cetabolites from different origins.

Wu Wei Zi (Schisandra chinensis), an important herbal medicine, is mainly distributed in the northeast of China. Its phytochemical compositions, which depend on geographical origin, climatic conditions and cultural practices, may vary largely among Wu Wei Zi from different areas. In this study, we applied a comprehensive metabolite profiling approach using GC-TOF-MS, ultra-performance LC (UPLC) quadrupole TOF (QTOF) MS and inductively coupled plasma MS to systematically investigate the metabolite variations of S. chinensis from four different areas including Heilongjiang, Liaoning, Jilin, and Shanxi of China. A total of 65 primary metabolites, 35 secondary metabolites and 64 inorganic elements were identified. Several primary metabolites, including shikimic acid and tricarboxylic acid cycle intermediates, were abundant in those located in Heilongjiang, Jilin, and Liaoning. Besides, bioactive lignans are also highly abundant in those from northeastern China than those from northwestern China. Inorganic elements varied significantly among the different locations. Our results suggested that the metabolite profiling approach using GC-TOF-MS, ultra-performance LC quadrupole TOF MS, and inductively coupled plasma MS is a robust and reliable method that can be effectively used to explore subtle variations among plants from different geographical locations.

Serum Bile Acids Are Associated with Pathological Progression of Hepatitis B-Induced Cirrhosis

Recent metabonomic studies have identified an important role of bile acids in patients with liver cirrhosis. Serum bile acids, such as glycocholate (GCA), glycochenodeoxycholate (GCDCA), taurocholate (TCA), and taurochenodeoxycholate (TCDCA), increased significantly in liver cirrhosis patients. Our recently published urinary metabonomic study showed that glycocholate 3-glucuronide, taurohyocholate, TCA, glycolithocholate 3-sulfate, and glycoursodeoxycholate (GUDCA) were markedly increased in hepatitis B-induced cirrhotic patients (n = 63) compared with healthy controls (n = 31). The urinary levels of GUDCA were able to differentiate among three stages of cirrhotic patients with Child-Pugh (CP) score A, B, and C. In this study, we recruited two new cohorts of patients with hepatitis-B-induced cirrhosis and healthy control subjects and quantitatively profiled their serum bile acids using ultra-performance liquid chromatography triple quadrupole mass spectrometry. Serum bile acid profile and corresponding differential bile acids were characterized, in addition to the blood routine, liver, and renal function tests. The alterations of bile acids contributing to the intergroup variation between healthy controls and cirrhotic patients and among pathological stages of CP grade A, B and C were also investigated. Five bile acids, GCA, GCDCA, TCA, TCDCA, and GUDCA, were significantly altered among different stages of liver cirrhosis (n = 85), which was validated with an independent cohort of cirrhotic patients (n = 53). Our results show that dynamic alteration of serum bile acids is indicative of an exacerbated liver function, highlighting their potential as biomarkers for staging the liver cirrhosis and monitoring its progression.

Sex-dependent effects on gut microbiota regulate hepatic carcinogenic outcomes

Emerging evidence points to a strong association between sex and gut microbiota, bile acids (BAs), and gastrointestinal cancers. Here, we investigated the mechanistic link between microbiota and hepatocellular carcinogenesis using a streptozotocin-high fat diet (STZ-HFD) induced nonalcoholic steatohepatitis-hepatocellular carcinoma (NASH-HCC) murine model and compared results for both sexes. STZ-HFD feeding induced a much higher incidence of HCC in male mice with substantially increased intrahepatic retention of hydrophobic BAs and decreased hepatic expression of tumor-suppressive microRNAs. Metagenomic analysis showed differences in gut microbiota involved in BA metabolism between normal male and female mice, and such differences were amplified when mice of both sexes were exposed to STZ-HFD. Treating STZ-HFD male mice with 2% cholestyramine led to significant improvement of hepatic BA retention, tumor-suppressive microRNA expressions, microbial gut communities, and prevention of HCC. Additionally the sex-dependent differences in BA profiles in the murine model can be correlated to the differential BA profiles between men and women during the development of HCC. These results uncover distinct male and female profiles for gut microbiota, BAs, and microRNAs that may contribute to sex-based disparity in liver carcinogenesis, and suggest new possibilities for preventing and controlling human obesity-related gastrointestinal cancers that often exhibit sex differences.

Tryptophan Predicts the Risk for Future Type 2 Diabetes.

Recently, 5 amino acids were identified and verified as important metabolites highly associated with type 2 diabetes (T2D) development. This report aims to assess the association of tryptophan with the development of T2D and to evaluate its performance with existing amino acid markers. A total of 213 participants selected from a ten-year longitudinal Shanghai Diabetes Study (SHDS) were examined in two ways: 1) 51 subjects who developed diabetes and 162 individuals who remained metabolically healthy in 10 years; 2) the same 51 future diabetes and 23 strictly matched ones selected from the 162 healthy individuals. Baseline fasting serum tryptophan concentrations were quantitatively measured using ultra-performance liquid chromatography triple quadruple mass spectrometry. First, serum tryptophan level was found significantly higher in future T2D and was positively and independently associated with diabetes onset risk. Patients with higher tryptophan level tended to present higher degree of insulin resistance and secretion, triglyceride and blood pressure. Second, the prediction potential of tryptophan is non-inferior to the 5 existing amino acids. The predictive performance of the combined score improved after taking tryptophan into account. Our findings unveiled the potential of tryptophan as a new marker associated with diabetes risk in Chinese populations. The addition of tryptophan provided complementary value to the existing amino acid predictors.

Very Low Carbohydrate Diet Significantly Alters the Serum Metabolic Profiles in Obese Subjects

Emerging evidence has consistently shown that a very low carbohydrate diet (VLCD) can protect against the development of obesity, but the underlying mechanisms are not fully understood. Here we applied a comprehensive metabonomics approach using ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry and gas chromatography-time-of-flight mass spectrometry to study the effects of an 8-week dietary intervention with VLCD on serum metabolic profiles in obese subjects. The VLCD intervention resulted in a weight loss and significantly decreased homeostasis model assessment-insulin resistance. The metabonomics analysis identified a number of differential serum metabolites (p < 0.05) primarily attributable to fatty acids, amino acids including branched chain amino acids, amines, lipids, carboxylic acids, and carbohydrates in obese subjects compared to healthy controls. The correlation analysis among time, VLCD intervention, and clinical parameters revealed that the changes of metabolites correlated with the changes of clinical parameters and showed differences in males and females. Fatty acids, amino acids, and carboxylic acids were increased in obese subjects compared with their normal healthy counterparts. Such increased levels of serum metabolites were attenuated after VLCD intake, suggesting that the health beneficial effects of VLCD are associated with attenuation of impaired fatty acid and amino acid metabolism. It also appears that VLCD induced significant metabolic alterations independent of the obesity-related metabolic changes. The altered metabolites in obese subjects post-VLCD intervention include arachidonate, cis-11,14-eicosadienoate, cis-11,14,17-eicosatrienoate, 2-aminobutyrate, acetyl-carnitine, and threonate, all of which are involved in inflammation and oxidation processes. The results revealed favorable shifts in fatty acids and amino acids after VLCD intake in obese subjects, which should be considered biomarkers for evaluating health beneficial effects of VLCD and similar dietary interventions.

The Brain Metabolome of Male Rats across the Lifespan

Comprehensive and accurate characterization of brain metabolome is fundamental to brain science, but has been hindered by technical limitations. We profiled the brain metabolome in male Wistar rats at different ages (day 1 to week 111) using high-sensitivity and high-resolution mass spectrometry. Totally 380 metabolites were identified and 232 of them were quantitated. Compared with anatomical regions, age had a greater effect on variations in the brain metabolome. Lipids, fatty acids and amino acids accounted for the largest proportions of the brain metabolome, and their concentrations varied across the lifespan. The levels of polyunsaturated fatty acids were higher in infancy (week 1 to week 3) compared with later ages, and the ratio of omega-6 to omega-3 fatty acids increased in the aged brain (week 56 to week 111). Importantly, a panel of 20 bile acids were quantitatively measured, most of which have not previously been documented in the brain metabolome. This study extends the breadth of the mammalian brain metabolome as well as our knowledge of functional brain development, both of which are critically important to move the brain science forward.

Herbal medicine Yinchenhaotang protects against α-naphthylisothiocyanate-induced cholestasis in rats

Cholestasis is a clinical disorder defined as an impairment of bile flow, and that leads to toxic bile acid (BA) accumulation in hepatocytes. Here, we investigated the hepatoprotective effect of Yinchenhaotang (YCHT), a well-known formulae for the treatment of jaundice and liver disorders, against the cholestasis using the α-naphthylisothiocyanate (ANIT)-induced cholestasis in male Wistar rats. ANIT feeding induced significant cholestasis with substantially increased intrahepatic retention of hydrophobic BAs. The dynamic changes of serum and liver BAs indicated that YCHT was able to attenuate ANIT-induced BA perturbation, which is consistent with the histopathological findings that YCHT significantly decreased the liver damage. YCHT treatment substantially reduced serum alanine aminotransferase (ALT), alkaline phosphatase (AST), total bilirubin (TBIL) and direct bilirubin (DBIL) with minimal bile duct damage in the ANIT treated rats. Elevated mRNA expression of liver IL-6, IL-17A, IL-17F, TGF-β1, α-SMA, TGR5, NTCP, OATP1a1, and ileum ASBT and decreased liver IL-10, FXR, CAR, VDR, BSEP, MRP2, MRP3, MRP4 was also observed in ANIT-induced cholestasis but were attenuated or normalized by YCHT. Our results demonstrated that the BA profiles were significantly altered with ANIT intervention and YCHT possesses the hepatoprotective potential against cholestatic liver injury induced by hepatotoxin such as ANIT.