Trimethylamine N-oxide aggravates vascular permeability and endothelial cell dysfunction under diabetic condition:in vitro and in vivo study

AIM:To provide the direct evidence for the crucial role of trimethylamine N-oxide(TMAO)in vascular permeability and endothelial cell dysfunction under diabetic condition.METHODS:The role of TMAO on the in vitro biological effect of human retinal microvascular endothelial cells(HRMEC)under high glucose conditions was tested by a cell counting kit,wound healing,a transwell and a tube formation assay.The inflammation-related gene expression affected by TMAO was tested by real-time polymerase chain reaction(RT-PCR).The expression of the cell junction was measured by Western blotting(WB)and immunofluorescence staining.In addition,two groups of rat models,diabetic and non-diabetic,were fed with normal or 0.1%TMAO for 16wk,and their plasma levels of TMAO,vascular endothelial growth factor(VEGF),interleukin(IL)-6 and tumor necrosis factor(TNF)-αwere tested.The vascular permeability of rat retinas was measured using FITC-Dextran,and the expression of zonula occludens(ZO)-1 and claudin-5 in rat retinas was detected by WB or immunofluorescence staining.RESULTS:TMAO administration significantly increased the cell proliferation,migration,and tube formation of primary HRMEC either in normal or high-glucose conditions.RT-PCR showed elevated inflammation-related gene expression of HRMEC under TMAO stimulation,while WB or immunofluorescence staining indicated decreased cell junction ZO-1 and occludin expression after high-glucose and TMAO treatment.Diabetic rats showed higher plasma levels of TMAO as well as retinal vascular leakage,which were even higher in TMAO-feeding diabetic rats.Furthermore,TMAO administration increased the rat plasma levels of VEGF,IL-6 and TNF-αwhile decreasing the retinal expression levels of ZO-1 and claudin-5.CONCLUSION:TMAO enhances the proliferation,migration,and tube formation of HRMEC,as well as destroys their vascular integrity and tight connection.It also regulates the expression of VEGF,IL-6,and TNF-α.

Trimethylamine N-oxide generation process was influenced by the proportion and source of macronutrients in the diet

Trimethylamine N-oxide(TMAO)is a risk factor of various chronic diseases,which was produced by metabolism from precursors to trimethylamine(TMA)in gut and the oxidation from TMA in liver.The TMA generation was influenced by diet,mainly due to the rich TMAO precursors in diet.However,it was still unclear that the effects of different proportion and source of macronutrients in different dietary pattern on the production process of TMAO.Here,the generation of TMA from precursors and TMAO from TMA was determined after single oral choline chloride and intraperitoneal injection TMA,respectively,in mice fed with carbohydrates,proteins and fats in different proportion and sources.The results suggested that the generation of TMAO was increased by low non-meat protein and high fat via enhancing the production of TMAO from TMA,and decreased by plant protein and refined sugar via reducing TMA production from precursors in gut and TMAO transformation from TMA in liver.The high fat and high sugar diets accelerating the development of atherosclerosis did not increase the production of TMAO,the risk factor for atherosclerosis,which indicated that the dietary compositions rather than the elevated TMAO level might be a more key risk factor for atherosclerosis.

Distinct influence of trimethylamine N-oxide and high hydrostatic pressure on community structure and culturable deep-sea bacteria

Trimethylamine N-oxide(TMAO)is one of the most important nutrients for bacteria in the deep-sea environment and is capable of improving pressure tolerance of certain bacterial strains.To assess the impact of TMAO on marine microorganisms,especially those dwelling in the deep-sea environment,we analyzed the bacterial community structure of deep-sea sediments after incubated under different conditions.Enrichments at 50 MPa and 0.1 MPa revealed that TMAO imposed a greater influence on bacterial diversity and community composition at atmospheric pressure condition than that under high hydrostatic pressure(HHP).We found that pressure was the primary factor that determines the bacterial community.Meanwhile,in total,238 bacterial strains were isolated from the enrichments,including 112 strains a ffiliated to 16 genera of 4 phyla from the Yap Trench and 126 strains a ffiliated to 11 genera of 2 phyla from the Mariana Trench.Treatment of HHP reduced both abundance and diversity of isolates,while the presence of TMAO mainly af fected the diversity of isolates obtained.In addition,certain genera were isolated only when TMAO was supplemented.Taken together,we demonstrated that pressure primarily defines the bacterial community and culturable bacterial isolates.Furthermore,we showed for the first time that TMAO had distinct influences on bacterial community depending on the pressure condition.The results enriched the understanding of the significance of TMAO in bacterial adaptation to the deep-sea environment.

Trimethylamine N-oxide attenuates high-fat high-cholesterol dietinduced steatohepatitis by reducing hepatic cholesterol overload in rats

BACKGROUND Trimethylamine N-oxide (TMAO) has been shown to be involved in cardiovascular disease (CVD). However, its role in nonalcoholic steatohepatitis (NASH) is unknown. AIM To determine the effect of TMAO on the progression of NASH. METHODS A rat model was induced by 16-wk high-fat high-cholesterol (HFHC) diet feeding and TMAO was administrated by daily oral gavage for 8 wk. RESULTS Oral TMAO intervention attenuated HFHC diet-induced steatohepatitis in rats. Histological evaluation showed that TMAO treatment significantly alleviated lobular inflammation and hepatocyte ballooning in the livers of rats fed a HFHC diet. Serum levels of alanine aminotransferase and aspartate aminotransferase were also decreased by TMAO treatment. Moreover, hepatic endoplasmic reticulum (ER) stress and cell death were mitigated in HFHC diet-fed TMAOtreated rats. Hepatic and serum levels of cholesterol were both decreased by TMAO treatment in rats fed a HFHC diet. Furthermore, the expression levels of intestinal cholesterol transporters were detected. Interestingly, cholesterol influxrelated Niemann-Pick C1-like 1 was downregulated and cholesterol efflux-related ABCG5/8 were upregulated by TMAO treatment in the small intestine. Gut microbiota analysis showed that TMAO could alter the gut microbial profile and restore the diversity of gut flora. CONCLUSION These data suggest that TMAO may modulate the gut microbiota, inhibit intestinal cholesterol absorption, and ameliorate hepatic ER stress and cell death under cholesterol overload, thereby attenuating HFHC diet-induced steatohepatitis in rats. Further studies are needed to evaluate the influence on CVD and define the safe does of TMAO treatment.

Contribution of trimethylamine N-oxide on the growth and pressure tolerance of deep-sea bacteria

Trimethylamine N-oxide(TMAO) is widely dispersed in marine environments and plays an important role in the biogeochemical cycle of nitrogen. Diverse marine bacteria utilize TMAO as carbon and nitrogen sources or as electron acceptor in anaerobic respiration. Alteration of respiratory component according to the pressure is a common trait of deep-sea bacteria. Deep-sea bacteria from dif ferent genera harbor high hydrostatic pressure(HHP) inducible TMAO reductases that are assumed to be constitutively expressed in the deep-sea piezosphere and facilitating quick reaction to TMAO released from ?sh which is a potential nutrient for bacterial growth. However, whether deep-sea bacteria universally employ this strategy remains unknown. In this study, 237 bacterial strains affliated to 23 genera of Proteobacteria,Bacteroidetes, Firmicutes and Actinobacteria were isolated from seawater, sediment or amphipods collected at dif ferent depths. The pressure tolerance and the utilization of TMAO were examined in 74 strains. The results demonstrated no apparent correlation between the depth where the bacteria inhabit and their pressure tolerance, regarding to our samples. Several deep-sea strains from the genera of Alteromonas, Halomonas,Marinobacter, Photobacterium, and Vibrio showed capacity of TMAO utilization, but none of the isolated Acinebacter, Bacillus, Brevundimonas, Muricauda, Novosphingobium, Rheinheimera, Sphingobium and Stenotrophomonas did, indicating the utilization of TMAO is a species-speci?c feature. Furthermore, we noticed that the ability of TMAO utilization varied among strains of the same species. TMAO has greater impact on the growth of deep-sea isolates of Vibrio neocaledonicus than shallow-water isolates. Taken together, the results describe for the ?rst time the TMAO utilization in deep-sea bacterial strains, and expand our understanding of the physiological characteristic of marine bacteria.

The relationship between serum trimethylamine N-Oxide level and carotid intima media thickness in untreated essential hypertension patients

Background Circulating trimethylamine N-Oxide （TMAO） level has been linked to adverse cardiovascular outcome and mortality in the general population, and atherosclerosis is a window of the cardiovascular disease. Therefore, the present study was designed to investigate the relationship between TMAO level and atherosclerosis in untreated essential hypertension patients. Methods We measured serum TMAO level in atherosclerosis, subclinical atherosclerosis and controls matched by age and sex. The link between serum TMAO level and CIMT was subsequently assessed. Results The level of serum TMAO was significantly higher in atherosclerosis pa- tients than in controls. Serum TMAO level was positively correlated with carotid intima media thickness （r = 0.783, P 〈 0.001）, and logistic regression indicated that TMAO was a risk factor of atherosclerosis （OR, 1.904; 95% CI, 1.197- 2.733, P 〈 0.001）. Conclusions Serum TMAO concentration positively correlates to carotid intima media thickness, and should be a good predicted biomarker for atherosclerosis.

Trimethylamine Adsorption Mechanism on Activated Carbon and Removal in Water and Oyster Proteolytic Solution

In this study,seven coal-based activated carbons(ACs)were adopted to remove trimethylamine(TMA)in an aqueous solution as environmentally friendly and harmless adsorbents.The results showed that columnar AC(CAC)had a clear scale and honeycomb structures with few fragments and micropores,contributing to superior TMA removal capacity compared to granular AC(GAC)(71.67%for 6.0 mm CAC and 69.92%for 40–60 mesh GAC).In addition,the process of adsorption was accompanied by desorption,and the recommended absorbed time was 120–180 min.The short time to achieve equilibrium indicated that adsorption was kinetically controlled,and pseudo-second-order kinetics was more appropriate than pseudo-first-order kinetics in explaining the adsorption mechanism in both water and oyster enzymatic hydrolysate.The intraparticle diffusion model presented that the adsorption processes could be divided into three steps for GAC and two steps for CAC.The adsorption processes were consistent with the Freundlich model,indicating the existence of physisorption and chemisorption as multilayer adsorption.The results indicated that AC,especially CAC,has great potential for TMA elimination in aquatic product processing.

Synthesis and Crystal Structure of a Zinc(II) Complex Salt with the Schiff Base of Picolinaldehyde N-oxide and Semicarbazone

The title zinc（Ⅱ） complex salt [Zn（H2O）6]（ClO4）2-（PNOS）4, where PNOS is derived from picolinaldehyde N-oxide with semicarbazone, has been prepared and structurally characterized by X-ray single-crystal analysis. It crystallizes in triclinic, space group PI with a = 7.529（3）, b = 10.206（4）, c = 14.678（6）A, a = 86.293（6）, β= 87.686（7）, γ= 81.382（6）°, C28H44Cl2N16O22Zn, Mr = 1093.06, V = 1112.3（8） ,A^3 Z = 1, Dc = 1.632 g/cm^3, S = 1.089, μ（MoKa） = 0.773 mm^-1, F（000） = 564, the final R = 0.0438 and wR = 0.1076 for 3888 independent reflections with Rint = 0.0224. The crystal structure possesses a [Zn（H2O）6]^2＋ cation, two ClO4^- anions and four PNOSs. In the crystal structure, Zn^2＋ cation is located at the symcenter and coordinated by six water molecules. In [Zn（H2O）6]^2＋, an elongate octahedral complex cation, the average Zn-O bond length is 2.087（2） A. There exist a lot of H bonds in the structure, linking the cation [Zn（H2O）6]^2＋, anion ClO4^- and PNOS to form a 3D network.

Hydrothermal Synthesis, Crystal Structure and Fluorescent Property of a Cd(Ⅱ) Complex Based on Biimidazole and Isonicotinate-N-oxide

A new complex [Cd（H2biim）2（H2O）2]·（ino）2·4H2O （H2biim = 2,2＇-biimidazole, ino = isonicotinate-N-oxide） has been prepared and characterized by single-crystal X-ray diffraction analysis, IR and fluorescence spectra analysis. The crystal is of triclinic system, space group P1 with a = 7.5380（6）, b = 8.0402（7）, c = 13.5094（11） , α = 104.269（1）, β = 93.604（1）, γ = 98.349（1）°, V = 780.93（11） 3, Mr = 765.00, Dc = 1.627 g/cm3, F（000） = 390, μ = 0.776 mm-1 and Z = 1. The final R = 0.0322 and wR = 0.0825 for 7038 observed reflections with I 2σ（I） and R = 0.0341 and wR = 0.0832 for all data. The title complex exhibits an infinite chain-like structure through bridging isonicotinate-N-oxide. Strong interchain hydrogen bonds between isonicotinate-N-oxide and H2biim result in the robust 3-D supramolecular architecture. Moreover, the complex shows strong photoluminescence with emission maximum at λ = 401 nm upon λex = 330 nm.

Separation of Inorganic Anions Using Methacrylate-Based Monolithic Column Modified with Trimethylamine in Ion Chromatography Capillary System

Methacrylate-based monolithic column was prepared in fused-silica capillary (80 ′ 0.32 mm i.d.) by in situ polymerizetion reaction using glycidyl methacrylate as monomer;ethylene dimethacrylate as crosslinker;1-propanol, 1,4-butanediol, and water as porogenic solvents. The monolith matrix was modified with trimethylamine to create strong anion exchanger via ring opening reaction of epoxy groups. The morphology of the monolithic column was studied by using Scanning Electron Microscope (SEM). This column had good mechanical stability and permeability. The effects of various mobile phases for separation of inorganic anions were investigated. Iodate, bromate, nitrite, bromide, and nitrate were separated within 11 min using100 mMpotassium chloride as mobile phase and detected at 210 nm. This method showed good precision of retention time, acceptable linearity and good sensitivity. Under the optimum condition, the RSD of the retention time was in the range of 1.09%-1.75% (n = 6). The calibration curve showed linear relationships between the peak area and the concentration. The limits of detection (LOD) and the limits of quantitation (LOQ) were between 0.08-0.18 mM and 0.26-0.61 mM, respectively. This method was applied to the determination of inorganic anions in tap water and ground water samples.

Semi-synthesis and Crystal Structure of Sophoridine N-oxide

Sophoridine N-oxide was synthesized and characterized by 1H-NMR,EI-MS,IR and elemental analysis,together with X-ray single-crystal diffraction analysis,and its crystal structure was reported for the first time.The crystal belongs to the orthorhombic system,space group P212121 with a = 8.321（2）,b = 15.650（3）,c = 24.352（5） ,V = 3171.1（11） 3,Z = 8,Dc = 1.258 g/cm3,λ（CuKα） = 1.54178,F（000） = 1440,the final R = 0.0351 and wR = 0.0970.The crystal structure shows Sophoridine N-oxide crystallizes with two host molecules of similar conformation and four water solvent molecules in the asymmetric unit.In the crystal structure,intermolecular O-H…O hydrogen bonds link the constituent molecules into a 2D layer structure,which further extends to a 3D supramolecular architecture via Van der Waals interactions and intermolecular O-H…O hydrogen bonds.

Spectrophotometric Determination of Trimethylamine-nitrogen in Cadaver Tissues for the Estimation of Late Postmortem Interval:A Pilot Study

To study the relationship between the late postmortem interval （PMI） and trimethyl-amine-nitrogen （TMA-N） in postmortem tissues of cadaver, TMA-N in muscles, livers and kidneys of rats was measured at different postmortem intervals （PMI） by using a modified spectrophotometric method. The results indicated that the detection sensitivity of TMA-N was 1 mg/L, and there was a good linear correlation between the value of absorbance （A value） and TMA-N at the concentration of 1-10 mg/L （R2=0.9991）. Although TMA variation in muscles was different from that in inner organs during the time since death, TMA-N changes in cadaver tissues was positively correlated with PMI. During 2 to 7d since death, the best correlation between PMI and TMA-N concentration was found in muscles. With PMI as an independent variable, the cubic polynomial regression equation was y=-0.457x3 ＋6.519x2-24.574x＋27.207 （R2=0.969）. During 3 to 8 days since death, PMI was best correlated with TMA-N concentration in inner organs. With PMI as the independent variable, the cubic polynomial regression equation was y=0.509x3-9.153x2＋55.727x-95.819 （R2=0.953）. It was concluded that TMA-N in tissues could be used as a new estimator for late PMI. The method used in this study offered advantages such as accuracy, sensitivity, little samples required and wide PMI estimation.

PREPARATION AND MECHANISM OF 7,17-SECO C_(19)-DITERPENOID ALKALOIDS VIA PYROLYSIS OF THEIR N-OXIDES IN DIGLYME

A new preparation method of the N-ethyl 7,17-seco C_(19)-diterpenoid alkaloids(5)and(6)by pyrolysis of the N-oxides(3)and(4),respectively, in anhydrous diglyme is described.A probable reaction mechanism for the pyroly- sis is presented and studied preliminarily.

Crebanine N-oxide, a natural aporphine alkaloid isolated from Stephania hainanensis, induces apoptosis and autophagy in human gastric cancer SGC-7901 cells

Objective: To investigate the cytotoxic effects and the potential mechanisms of crebanine N-oxide in SGC-7901 gastric adenocarcinoma cells. Methods: The cytotoxicity of crebanine N-oxide was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay and cellular morphology was observed under a microscope. Cell apoptosis was determined by flow cytometry using propidium iodide staining. The expression levels of apoptotic-related proteins, cleaved caspase-3, cytochrome C, p53 and Bax, and autophagyrelated proteins p62, beclin1 and LC3 were detected by Western blotting assays. Results: Crebanine N-oxide treatment significantly inhibited the proliferation of SGC-7901 cells in a dose-dependent and timedependent manner via induction of G2-phase cell cycle arrest, apoptosis, and autophagy in SGC-7901 cells.Conclusions: Crebanine N-oxide could inhibit the growth of gastric cancer cells by promoting apoptosis and autophagy and could be used as a potential agent for treating gastric cancer.

Synthesis and Crystal Structure of Tri-(2-mercaptopyridine N-oxide)bis(dimethyl sulfoxide) Dysprosium(III)

A range of rare earth metal complexes of 2-mercaptopyridine N-oxide (Hmpo) have been synthesized, and studied by elemental analysis and IR spectroscopic technique. Crystal structure of Dy(mpo)3(DMSO)2 (DMSO = dimethyl sulfoxide) has been determined. The complex crystallizes in the triclinic system, space group P with lattice parameters: a = 9.602(3), b = 9.803(3), c = 15.498(5) ? a = 89.51(1), b = 85.73(1), g = 62.99(1)? Dc = 1.787 g/cm3, C19H24N3O5S5Dy, Mr = 697.21, Z = 2, F(000) = 690, = 3.321mm-1, the final R = 0.0237 and wR = 0.0587 for 4116 reflections with I > 2s(I). The coordination number of dysprosium (Ⅲ) is eight, and its coordination geometry is a somewhat distorted square antiprism with O(3), O(4), O(5), S(3) and O(1), O(2), S(1), S(2) at the tetragonal bases (dihedral angle between their mean planes is 2.9(1)). Around the Dy atom, three five-membered ring planes (Dy, O, N, C, S) make the dihedral angles of 74.42, 11.31 and 83.72, respectively.

Ternary Complexes of Rare Earth Nitrate with B-15-C-5 and 4-Picoline N-Oxide

A series of ternary complexes of rare earth(Ⅲ)nitrate with benzo-15-crown-5 and 4-picoline N-oxide have been prepared.They have the general formula of RE(NO_3)_3·2(4-picNO)·3H_2O·(1/2)(B-15-C-5) (RE=La～Tm).Their physico-chemical properties have also been studied with conductance,thermal analysis and IR absorption spectroscopy.

Brucine N-oxide reduces ethanol intake and preference in alcohol-preferring Fawn-Hooded rats

OBJECTIVE The alcoholism-related social problems have burdened the public health heavily.A better therapy for alcohol dependence as a chronic brain disease is highly required and interests the scientists worldwide. Our group has focused on screening the right drug with low toxicity and a sound curative effect from traditional Chinese medicine. METHODS Alcohol-preferring Fawn-Hooded(FH/Wjd) rat was used as an animal model of alcoholism to evaluate the effects of brucine N-oxide(BNO),an alkoloid naturally existing in the seeds of Strychnos nux-vomica L,on the alcohol-drinking behaviors.Furthermore,its adverse action and toxicity were investigated. RESULTS Treatment with BNO at the doses of 30,50 and 70 mg · kg^(-1)reduced the voluntary alcohol consumption and preference dosedependently and selectively without altering their water intake,total fluid intake,food consumption,body weight as well as sucrose preference. Remarkably,70 mg·kg^(-1)of BNO did suppress the deprivationinduced elevation of alcohol ingestion. Moreover,BNO used at the same doses as above had no influence on locomotion in an open field test and could not result in the place preference effect. CONCLUSION Taken together,BNO is of some significant pharmacological profiles to inhibit symptoms of alcohol dependence with high safety,and thence may be a potential pharmacotherapy.

Synthesis and Crystal Structure of 3-Nitrophthalic Acid·3-methyl-4-nitropyridine N-Oxide Adducts

The title compound, a 1：1 molecular adduct of 3-nitrophthalic acid and 3-methyl- 4-nitropyridine N-oxide （PPOM）, has been synthesized and characterized by X-ray single-crystal structure analysis. It crystallizes in triclinic, space group PI with α = 7.6076（15）, b = 7.8180（16）, c = 14.546（3）A, α= 93.90（3）, β = 97.21（3）, γ= 114.43（3）°, C14H1N3O9, Mr = 365.26, Z = 2, V = 774.6（3） A^3, Dc = 1.566 g/m^3,μ（MoKa） = 0.134 mm^-1, F（000） = 376, R = 0.0538 and wR = 0. 1460 for 885 observed reflections （1 〉 2σ（I））. The protons of the carbonylic acids in the molecule are not transferred and the O-H…O and C-H…O hydrogen bonds form zigzag chains in the molecule.

Syntheses and Crystal Structures of (PySe)_2 and Bi_2(PySe)_6(HPySe=2-Pyridineselenol N-Oxide)

The title compounds（PySe）2 1（HPySe=2-pyridineselenol N-oxide,（PySe）2= bis（2-pyridine-N-oxide） diselenide） and Bi2（PySe）6 2 were prepared by the reaction of 2-bromine-N-oxide with NaHSe and Bi（NO3）3·5H2O with HPySe,and the crystal structure of 2 was studied.Compound 2 crystallizes in the monoclinic space group P21/n with a=9.840（2）,b=10.204（2）,c=18.395（2）,β=102.926（2）°,V=1800.0（5）3,Dc=2.2687 g/cm3,Z=2,the final R=0.0319 and wR=0.0646.The Bi atoms are coordinated by four selenium and four oxygen atoms from four PySe ligands to form a slightly distorted four-column geometry.

Synthesis,Crystal Structure and Fluorescence of a Three-dimensional Cd(II) Coordination Polymer [Cd(μ_(1,3)- SCN^-)_2(μ-dmpo)]_n (dmpo = 3,5-Dimethylpyridine N-Oxide)

A three-dimensional complex [Cd（μ1,3-SCN）2（dmpo）]n has been synthesized with μ1,3-SCN^- and dmpo as mixed bridge ligands. The crystal belongs to monoclinic, space group C2/c with a = 15.648（2）, b = 15.126（2）, c = 11.9773（15） A, β= 112.416（2）°, V= 2620.7（6） ,A, Z= 8, C9H9CdN3OS2, Mr = 351.71, Dc = 1.783 g/cm^3, F（000） = 1376 and μ = 1.967 mm^-1. The structure was refined to R = 0.0260 and wR = 0.0647 for 2186 observed reflections （I 〉 2σ（I））. In the crystal the Cd（Ⅱ） ions are coordinated by ,μ1,3-SCN^- bridge ligands to form the crossing chains on the adjacent planes, and these chains are further joined by μ-dmpo mono-dentate bridge ligands leading to a three-dimensional structure. The complex exhibits strong fluorescent emission property.