A novel approach for characterizing variations in serum peptides in rheumatic heart disease

Abstract

Background & objectives: Acute rheumatic fever and rheumatic heart disease (RHD) are important public health problems in developing countries. In this study, peptidomic analyses on RHD patients and healthy individuals were performed to characterize variations in serum peptide levels using label-free quantitation approaches.

Methods: Blood samples were obtained from 160 healthy controls and 160 RHD patients. Of the 448 identified peptides, 272 were analyzed by two label-free mass spectrometry methods, the spectral count and spectral index.

Results: There were 38 proteins and 95 peptides with significant (adjusted P<0.001) differences in the abundance of peptides between healthy controls and RHD patients, including multiple peptides derived from histone H2B, villin-like protein, complement C4-B and motile sperm domain containing protein-2. The levels of 10 peptides were upregulated, and 85 peptides were downregulated in patients compared to controls. In addition, in patients, the levels of four proteins were upregulated and 34 were downregulated compared to controls.

Interpretation & conclusions: This study shows that detection of significant changes in serum peptides reflects the difference between RHD patients and healthy controls. This label-free method may be helpful for clinicians to treat RHD patients during the perioperative period.

Fig. 1

Flow chart representing the study design and selection of participants into the healthy group and the rheumatic heart disease (RHD) groups. LC-MS, liquid chromatography- mass spectrometry.

Fig. 2

Graphical representation of the different protein levels in serum between the rheumatic heart disease patients and healthy controls. There were 38 proteins with a significant (adjusted P<0.001) difference between healthy controls and rheumatic heart disease patients. The serum levels of four proteins were upregulated and 34 were downregulated. The number on the y axis represents the fold change in protein level. The proteins are listed according to their SWISS-PROT accession number.

Fig. 3

Graphical representation of the different peptide levels in serum between the rheumatic heart disease patients and healthy controls. There were 95 peptides with a significant (adjusted P<0.001) difference in abundance of peptide between healthy controls and rheumatic heart disease patients. The serum levels of 10 peptides were upregulated and 85 peptides were downregulated. The number on the y axis represents the fold change in peptide level. The peptides are listed according to their SWISS-PROT accession number.