Hypertension Metabolomics Research

Metabonomics or metabolomics is the quantitative measurement of the multiparametric time-related metabolic responses of a complex system to a pathophysiological intervention or genetic modification.Metabolomics apply useful modeling tools for the classification and prediction of physiological and pathological states from metabolite profiles of biofluids such as plasma and urine.Thus metabonomics seeks to assess the global system level homeostatic and pathological responses to interventions or stressors.The main characteristics of metabonomics are the high-throughput experiment and calculation.As a new methodology, metabonomics has become an important hotspot for the research of disease and healthy in the world now.Therefore,to research hypertension with metabonomic method is significant for the early-stage diagnose and prevention of disease and drug intervention.In the present study,we have developed HPLC and ICP-MS approaches as determination means of metabolomics,to differentiate healthy persons and hypertension patients.Plasma and urine metabolite content from healthy persons and hypertension patients were acquired using HPLC and ICP-MS methods.It was unable to distinguish plasma and urine metabolite chromatography from healthy persons and hypertension patients.Using pattern recognition,it was capable of distinguishing normal blood pressure plasma and urine samples from hypertension patients.It was showed that the analysis of metabolite in plasma and urine can recognize hypertension condition.The present study was a successful research of hypertension using metabolomics approach.The study provided theory for the early-stage diagnose and prevention of disease and pathopoiesis mechanism.1.Determination of nonprotein-nitrogen metabolites in urine by RP-HPLC methodTo establish a RP-HPLC method for determinating 5 kinds of nonprotein-nitrogen metabolites in urine(urea,creatine,creatinine,uric acid and hippuric acid).The urine samples were centrifugated and diluted prior to analysis.The five compounds were successfully separated on a C₁₈column using a mobile phase of acetonitrile-ammonium acetate (20 mmol·L^-1,pH 6.8)with gradient elution.The detection wavelength was selected at 220 nm.The method was linear over the concentration range of 2 to 100 mg·mL^-1for creatine,uric acid,creatinine and hippuric acid,and 100 to 1000 mg·mL^-1for urea(γ＞0.99).The mean recovery was between 97.6%and 105%.The RSD was between 0.79%and 4.2%(n=6).The method was simple,rapid,sensitive and accurate,and was suitable for rapid analysis of nonprotein-nitrogen metabolites in urine.2.Determination of amino acids in plasma and urine by pre-column derivatization HPLC methodA RP-HPLC method for determination of 22 amino acids in plasma and urine was established.Dansyl chloride was used as pre-column derivatization agent.The plasma and urine samples were precipitated protein prior to analysis.The 22 amino acid derivatives were successfully separated on a C₁₈column using a mobile phase of sodium acetate-methanoltetrahydrofuran with gradient elution.The fluorescence detection was used for determination. The assay was linear over the concentration range of 2 to 400μmol·L^-1for all amino acids (γ＞0.99).The mean recoveries were between 82.0%and 109%.The RSDs were between 0.98%and 7.3%(n=6).It indicated that the method has good precision and repeatability.The method was suitable to determinate amino acids in plasma and urine.3.Determination of trace element in urine by inductive coupled plasma mass spectrometry methodThe paper presented a method for the fast,simple and reliable routine determination of 16 trace elements in urine by ICP-MS.The urine samples were centrifugated and diluted prior to analysis.ICP-MS operating conditions:power 1570 W;outer gas flow 1.2 L·min^-1;plasma gas flow 14.9 L·min^-1;spray chamber temperature 2℃.The assay was linear over the concentration range of 0.1 to 100μg·L^-1for Al,V,Cr,Mn,Co,Ni,Cu,Zn,As,Se,Mo,Cd,Ba and Pb,and 10 to 10000μg·L^-1for Mg and Fe(γ＞0.999).The limit of determination was between 2 to 143 ng·L^-1.The precision of instrument was between 0.25% and 3.7%(n=10).The precision of method was between 0.79%and 4.9%(n=6).The method was simple,rapid and sensitive,and suitable for determination of trace element in urine.4.Data processing and result analysisPrincipal component analysis and discriminant analysis with SPSS13.0 statistics software,were used to process amino acid and trace element concentration from healthy people and hypertension patients.The result indicated that there was significance differentiation in amino acids and trace element metabolism mode between healthy people and hypertension patients.Using principal component analysis,it was capable of distinguishing normal blood pressure plasma and urine samples from hypertension patients. The classification accuracy was more than 98%.There was metabolism abnormality of amino acids in hypertension patients.The diet structure may affect the disorder.Disequilibrium of amino acids may be another reason.There was metabolism abnormality of trace element in hypertension patients.Besides diet structure and heredity factor,environment factor may be another important reason.Further study is in progress.