<b>OBJECTIVEb>To establish a high-performance capillary electrophoresis (HPCE)-based method for detection of trace amount of urinary fibrinopeptide A and B (FPA and FPB, respectively) as the specific molecular markers of thrombus formation in vivo.

<b>METHODSb>The HPCE system consisted of a 25 cm x 50 microm (inner diameter) coated capillary column, 0.1 mol/L phosphoric acid buffer (pH 2.5) and a UV-detector (wavelength at 190 nm). To improve the sensitivity and reproducibility, solid-phase extraction of FPA and FPB in the urine was performed using a Sep-pak C18 column, with a synthetical fibrinopeptide B-Tyr (FPB-Tyr) as the internal standard.

<b>RESULTSb>With this HPCE method, optimal separations of FPA, FPB and FPB-Tyr was achieved within 16 min, with the migration time of 7.28 min, 14.31 min and 15.22 min, respectively. The adjusted peak area ratios of FPA or FPB and the internal standard showed good linearity with the corresponding concentrations of FPA or FPB spiked in the urine(R>0.99). Under the above chromatography conditions, the minimum detection concentration of FPA and FPB in untreated urine was 30 microg/L and 40 microg/L, respectively, and the assay precision and recovery of FPA and FPB were acceptable.

<b>CONCLUSIONb>The method we established is reliable and specific for separation and identification of fibrinopeptides and other bioactive peptides.

Electrophoresis, Capillary ; methods ; Fibrinopeptide A ; urine ; Fibrinopeptide B ; urine ; Humans ; Reproducibility of Results

Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infections. Qingfei oral liquid (QFOL), a traditional Chinese medicine, is widely used in clinical treatment for RSV-induced pneumonia. The present study was designed to reveal the potential targets and mechanism of action for QFOL by exploring its influence on the host cellular network following RSV infection. We investigated the serum proteomic changes and potential biomarkers in an RSV-infected mouse pneumonia model treated with QFOL. Eighteen BALB/c mice were randomly divided into three groups: RSV pneumonia model group (M), QFOL-treated group (Q) and the control group (C). Serum proteomes were analyzed and compared using a label-free quantitative LC-MS/MS approach. A total of 172 protein groups, 1009 proteins, and 1073 unique peptides were successfully identified. 51 differentially expressed proteins (DEPs) were identified (15 DEPs when M/C and 43 DEPs when Q/M; 7 DEPs in common). Classification and interaction network showed that these proteins participated in various biological processes including immune response, blood coagulation, complement activation, and so forth. Particularly, fibrinopeptide B (FpB) and heparin cofactor II (HCII) were evaluated as important nodes in the interaction network, which was closely involved in coagulation and inflammation. Further, the FpB level was increased in Group M but decreased in Group Q, while the HCII level exhibited the opposite trend. These findings not only indicated FpB and HCII as potential biomarkers and targets of QFOL in the treatment of RSV pneumonia, but also suggested a regulatory role of QFOL in the RSV-induced disturbance of coagulation and inflammation-coagulation interactions.
Animals ; Biomarkers ; blood ; Chromatography, Liquid ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Fibrinopeptide B ; analysis ; genetics ; Gene Expression Regulation ; drug effects ; Heparin Cofactor II ; analysis ; genetics ; Lung ; pathology ; Mice, Inbred BALB C ; Proteome ; drug effects ; Proteomics ; Respiratory Syncytial Virus Infections ; blood ; drug therapy ; Respiratory Syncytial Viruses ; drug effects ; Tandem Mass Spectrometry