Study On The Mechanism Of Functional Dyspepsia Based On Metabolomics And

BackgroundFunctional dyspepsia (FD) belongs to the field of functional gastrointestinal disorders (FGIDs) and follows a chronic and fluctuating course, and there are nearly 15-20% of patients who claim the persistent symptoms. However, conventional treatments, including lifestyle adjustments, acid inhibitory drugs, prokinetic drugs, psychotropic agents and even Helicobacter pylori (HP) eradication, often remain unsatisfactory. Therefore, up to 50% patients seek out for other therapies, such as complementary and alternative medicine (CAM).Chinese herbal medicine (CHM) has advantages in improving global symptoms and quality of life. With more than 20 years of clinical experience, Professor Wei Wei developed an herbal formulation named Weikangning according to the Xinkai Kujiang method in treating FD, and Weikangning has been proved as an effective and safe therapy against FD by clinical trials. Also, based on animal and molecular experiments, and proteomics, the mechanism of action for the benefits of Weikangning in FD may involve in the promoting gastric motility, regulating visceral hypersensitivity, adjusting stomach muscle activity and autonomic nervous function, and improving antioxidant ability, energy metabolism and function of mitochondria.System review (SR) is an important research method and the best source of evidences for evidence-based medicine (EBM). As a research type of SR, meta analysis provides high-grade evidences for clinical research and practice and is widely used in the field of clinical medicine.Metabonomics, as a branch of system biology, studies in the metabolic terminal changes in living bodies that relate directly to integrated system activity influenced by different factors. Corresponding properly with the holistic, dynamic concept of Chinese medicine, metabonomics provides a new approach to uncover material bases and pharmacodynamic actions of Chinese medicine and becomes a research hotspot in field of Chinese herbal medicine.ObjectiveIn this study, NMR-based metabonomics was used to screen and identify the changes of endogenous metabolites in stressed rat serum and urine. The primary goal was to determine the potential biomarkers and metabolic pathways of FD stressed model and explore the intervention mechanism of Chinese medicine Weikangning, the representative formula of Xinkai Kujiang method, in the treatment of FD.Methods1. Literature review and system reviewBased on domestic and foreign literatures, lastest developments in treating FD with Western medicine and Chinese medicine and studing CHM with metabonomics were demonstrated. Meanwthile, the method of meta analysis was adopted to evaluate the efficacy and safety of CHM in treating FD. Web of Science, PubMed, EMBASE, Cochrane Library, and four other Chinese electronic databases, including China National Knowledge Infrastructure (CNKI), Chinese Biological Medical Database (CBM), Chinese Scientific Journals Database (VIP), and WanFang Database were used to search for randomized, double-blind, placebo-controlled trials recruiting adults with FD treated with CHM. Study selection, data extraction, quality assessment, and data analyses were conducted based on Cochrane standards using Review Manager software.2. Metabonomics research30 male Wistar rats were divided into two groups randomly,20 rats for the FD model group (MS group) and 10 rats for the normal control group (NS group). FD model adopted the method of stimulating rats via tail damping. After 7-day modeling establishment, half rats of MS group were selected randomly as Weikangning-treated group (WKN group). Then, WKN group was treated with Chinese medicine Weikangning according to clinical dosage, while MS and NS group were given purified water. All rats were administered with drugs or purified water via gastric intubation for 14 days. Urine samples were collected on pre-dose day 0,4,7 and post-dose day 4,7,11,14 through individual metabolism cages, and serum samples were collected after drug administration from abdominal aorta. Samples were analyzed by a VARIAN VNMRS 600 MHz NMR spectrometer, and all of the NMR spectra were corrected manually by MestReNova7.1.0. The results were imported into SIMCA-P+12.0 for multivariate statistical analysis, and principal component analysis (PCA) model, latent structures-discriminant analysis (PLS-DA), and orthogonal PLS-DA (OPLS-DA) were performed to model analyses. Variable importance in projection (VIP) value and correlation coefficient (Pcorr) were both used to select the metabolites with statistically significant differences.Results1. Literature review and system reviewBased on the principle of individualized treatment, symptomatic treatment is the primary method in Western medicine for treating FD. First-line treatments includs lifestyle adjustments, acid inhibitory drugs, prokinetic drugs, while second-line treatments includes psychotropic agents and CAM. HP eradication is recommended to the patients with HP infection. Treatments of FD with CHM mainly contents classic formula, empirical formula, syndrome differentiation and integrated Chinese and Western medicine. Metabonomics used in the field of CHM researches mainly focuses on Chinese medicine syndrome (CMS), Western medicine diseases, integrated disease and syndrome, pharmacodynamical mechanism, regularity in drug combination, toxicity assessment and decocting methods.Fourteen publications (1424 patients) were included. Evidence showed that CHM was more effective than the placebo in improving global dyspepsia symptoms (relative risk 1.45,95% CI[1.31-1.60]; Z=7.29, P<0.00001), CMS (relative risk,1.36,95%CI[1.23-1.50]; Z=6.17, P<0.00001), and quality of life (standardized mean difference 0.30,95%CI[0.15-0.45]; Z= 3.80, P=0.0001) in FD patients. Furthermore, there was no significant difference in the incidence of adverse events between CHM groups and placebo groups (relative risk 1.06,95% CI[0.66-1.70]; Z=0.23, P=0.82).2. Metabonomics researchMetabonomic analysis of urine samples:in the FD model establishment, the urine samples of MS group compared to NS group showed up-regulation of leucine, lactate, alanine, dimethylamine, phenylacetylglycine, hippurate, allantoin, cytidine, tyrosine, imidazole and phenylalanine and down-regulation of acetate, N-acetylglutamate, succinate,2-oxoglutarate, citrate and trimethylamine; in the drug intervention, the urine samples of WKN group compared to MS group showed up-regulation of N-acetylglutamate, glucose, creatine, hippurate, trigonelline and formate and down-regulation of 2-hydroxyvalerate, leucine, alanine, adipate, glycine, cis-aconitate and phenylalanine.Metabonomic analysis of serum samples:in the development of FD model, the serum samples of MS group compared to NS group manifested up-regulation of isoleucine, leucine, proline, methanol and down-regulation of glucose; in the drug administration, the serum samples of WKN group compared to MS group exhibited up-regulation of glucose and down-regulation of proline, glutamate,3-hydroxybutyrate, citrate, methionine, glycerol,1-methylhistidine, phenylalanine and formate.There were six potential target pathways (phenylalanine, tyrosine and tryptophan biosynthesis, citrate cycle (TCA cycle or Krebs cycle), phenylalanine metabolism, valine, leucine and isoleucine biosynthesis, glyoxylate and dicarboxylate metabolism and tyrosine metabolism) found in the process of model establishment. On the other hand, six potential target pathways (glyoxylate and dicarboxylate metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, glycine, serine and threonine metabolism, phenylalanine metabolism, valine, leucine and isoleucine biosynthesis and glycerolipid metabolism) were identified in the process of drug treatment.Conclusions1. Through literature review and system review, effective treatments of FD need to integrate Western medicnine, Chinese medicine and EBM to achieve complementary advantages of Western and Chinese medicine. Meanwhile, metabonomics has wide application foreground in the field of CHM researches.2. The disturbances of energy metabolism, stress-related metabolism, and gut microbiota occur in stressed FD model rats revealed by the findings of metabolic profiling of urine and serum samples compared with normal rats. After drug intervention, the metabolic profiling of stressed FD model rats has a trend to return to the normal condition, and this finding indicates the potential beneficial implications of Weikangning in treating FD for improving energy metabolism, stress-related metabolism, and gut microbiota related to the regulation of metabolic disorders...