An integrated metabonomic and proteomic study on Kidney-Yin Deficiency Syndrome patients with diabetes mellitus in China

Abstract

Aim: To investigate specific changes in metabolites and proteins of Kidney-Yin Deficiency Syndrome (KYDS) patients with diabetes mellitus (DM) in China.

Methods: KYDS (n=29) and non-KYDS (n=23) patients with DM were recruited for this study. The KYDS was diagnosed by two senior TCM clinicians separately. The metabonomic and proteomic profiles of the patients were assessed using a metabonomic strategy based on NMR with multivariate analysis and a proteomic strategy based on MALDI-TOF-MS, respectively.

Results: Eighteen upregulated peptides and thirty downregulated peptides were observed in the plasma of the KYDS patients. Comparing the proteomic profiles of the KYDS and non-KYDS groups, however, no significantly differentially expressed peptides were found. At the same time, major metabolic alterations were found to distinguish the two groups, including eight significantly changed metabolites (creatinine, citrate, TMAO, phenylalanine, tyrosine, alanine, glycine and taurine). The levels of creatinine, citrate, TMAO, phenylalanine and tyrosine were decreased, whereas the levels of alanine, glycine and taurine were increased in the KYDS patients. These biochemical changes were found to be associated with alterations in amino acid metabolism, energy metabolism and gut microflora.

Conclusion: The identification of distinct expression profiles of metabolites and signaling pathways in KYDS patients with DM suggests that there are indeed molecular signatures underlying the principles of 'Syndrome Differentiation' in traditional Chinese medicine.

Figure 1

Average spectrum profile and pseudo-gel view of training set. (A) Average spectrum profile of KYDS patients (red). X-axis: molecular mass (m/z); Y-axis: relative intensity. The five different signals of the diagnostic model are labeled with the values of m/z. (B) Average spectrum profile of non-KYDS patients (green). (C) Pseudo-gel view of individual spectra of training set. X-axis: molecular mass (m/z); Y-axis: specific samples; relative intensity: grade of blackening. The horizontal line in the view indicated the separation between KYDS (upper) and non-KYDS patients (lower).

Figure 2

600 MHz ¹H NMR spectra of the urine samples from (A) female KYDS patients, (B) female non-KYDS patients, (C) male KYDS patients and (D) male non-KYDS patients.

Figure 3

OSC-PCA scores plot from ¹H-NMR spectra of urine samples obtained from (•) KYDS patients and (▪) non-KYDS patients (A) and corresponding loadings plot (B).

Figure 4

Metabolite enrichment analysis on the 12 putative sets of metabolites that differed between the KYDS group and the non-KYDS group. Detailed results from this enrichment analysis are shown in Table 5.

Figure 5

Summary of pathway analysis on the 19 quantified variances from the KYDS and non-KYDS groups. Detailed results of the analysis are shown in Table 6. P values were calculated from enrichment analysis. The pathway impact values were calculated from pathway topology analysis. 1, taurine and hypotaurine metabolism; 2, glycine, serine and threonine metabolism; 3, phenylalanine metabolism.