Differentiation Of Gestational Diabetes Mellitus By Nuclear Magnetic Resonance-based Metabolic Plasma Analysis

Background Gestational diabetes mellitus(GDM)is a form of hyperglycemia that is recognized for the first time during pregnancy and is not clearly pre-existing type 1 or type 2 diabetes and which is one of common metabolic diseases during pregnancy with worldwide distribution.Poorly controlled GDM can cause severe short-term complications and long-term consequences for both mothers and their fetus.Pregnant women suffering from GDM may have complications including gestational polyhydramnios,hypertension and infection and are at increased risk of developing type 2 diabetes,cardiovascular disease and female malignancies later in life.In addition,GDM may increase the risk of macrosomia,respiratory distress syndrome(NRDS),hypoglycaemia and hyperbilirubinemia in neonates and other adverse health outcomes of the offspring.Metabolomics,one indispensable components of systems biology provides a unique approach to find the integrated function of a complex bio-system by quantitatively measuring the fluctuation of small-molecule metabolites.Among the techniques used in metabolomics,NMR has become a good choice,for its inherent advantages: non-bias for a wide range of metabolites,easy for quantification,non-destructive to sample,minimal sample processing and high throughput.GDM,as a heterogeneous disorder,is closely associated with insulin resistance in the second and third trimesters as a result of insulin antagonistic substances produced by the placenta.With increasing gestational age,the insulin antagonistic substances rise.Further,GDM is divided into two classes according to blood glucose control.GDM that is adequately controlled without medication is often termed class A1 GDM.GDM that requires medication to achieve euglycemia is often termed class A2 GDM.A2GDM is usually considered as more seriously than A1 GDM.However,most of published metabolic studies on GDM have not classified GDM group.The metabolic character difference between A1 GDM and A2 GDM is unknown.The differences in metabolic characteristics between A1 GDM and A2 GDM are not clear,and the results obtained from the studies are inconsistent.Therefore,this paper applied the metabolomics method based on nuclear magnetic resonance(NMR)to study different levels of GDM,and compared the differences of plasma metabolism and abnormalities of metabolic pathways that may be involved in pregnant women with diabetes with different degrees of disease before and after delivery.Furthermore,to explore the etiology and pathogenesis of GDM then to provide evidence for future prevention and intervention,the relationship between demographic parameters and the potential metabolites biomarkers were investigated.Purpose This study was to detect the difference of metabolic profile in A1 grade gestational diabetes mellitus(A1GDM)pregnant women and A2 grade gestational diabetes mellitus(A2GDM)pregnant women with 1H-NMR technique,discuss the relationship between plasma metabolites and demographic parameters through network analysis,explore the possible mechanism of GDM metabolic abnormalities,and explore the pathophysiological process of GDM.Content 1.Anthropometric parameters and biochemical indicators,such as Fasting plasma glucose(FPG),1 hr OGTT,2 hr OGTT,age,height,pre-pregnancy weight,pre-pregnancy BMI,pre-delivery weight,pre-delivery BMI,gain BMI,blood pressure,gestational weeeks,neonatal weight,neonatal weight ratio were detected in three groups of pregnant women.2.Blood samples were collected from 11 A2 GDM pregnant women(need insulin to control blood glucose),24 A1 GDM pregnant women(diet,exercise control blood glucose)and 35 NGT pregnant women before and after cesarean section surgery.Metabolic profiles were acquired using proton nuclear magnetic resonance spectroscopy(1H-NMR)and the data was analyzed by multivariate statistical data analysis.The difference of metabolites before and after delivery was further verified by hierarchical cluster analysis.The correlation analysis and network analysis between metabolites and demographic parameters were conducted.Results 1.Compared with NGT group,pregnant women in A1 GDM group were older,and pregnant women in A2 GDM group were shorter in height and lowerer in gestational weeks,showing significant differences.The levels of FBG,1 hr OGTT and 2 hr OGTT in the A2 GDM group were significantly higher than those in A1 GDM and NGT groups.No statistically significant differences were detected regarding systolic and diastolic blood pressure,among the three groups.2.The same group showed similar metabolic trends whether ante-partum or postpartum.Different class GDM pregnant women compared with NGT pregnant women,A total of 25 metabolites in plasma were identified,branched chain amino acids BCAAs(leucine,valine,isoleucine)aromatic amino acids(tyrosine and phenylalanine),glutamic acid and glutamine,glycine,lysine,2-hydroxybutyrate,acetate,formate,succinate increased significantly,3-hydroxybutyrate,3-Methyl-2-oxovalerate,methanol significantly decreased,and the more significant difference metabolites A2 GDM patients.Severe amino acid metabolism(branched chain amino acids,aromatic amino acids,glutamic acid and glutamine,etc.),energy metabolism(2-hydroxybutyric acid,3-hydroxybutyric acid,lactic acid,succinic acid,Cr /PCr,etc.)and metabolic disorders(hypoxanthine and other oxidative stress)occurred in GDM patients.3.On the second day after delivery,plasma metabolite levels of GDM patients were still significantly different from those of pregnant women in the NGT group.4.Correlation analysis and network analysis revealed that pre-pregnancy weight,pre-pregnancy BMI,pre-delivery weight and pre-delivery BMI were significantly correlated with a variety of different metabolites.Conclusions 1.The plasma metabolites of different class GDM group were significantly different from those of NGT group,and the A2 GDM group had more serious disturbed amino acid metabolism,energy metabolism and oxidative stress.2.There are still differences in metabolites in GDM patients on the second day after delivery,and the A2 GDM group was more significant,which may be related to long-term complications.3.Obese women are more likely to develop gestational diabetes.4.This integrated study provide a new idea and methods to understand underlying mechanism of mild GDM in clinic.