Identification of plasma protein biomarkers associated with idiopathic pulmonary arterial hypertension.
We have employed SELDI-TOF MS to screen for differentially expressed proteins in plasma samples from 27 patients with idiopathic pulmonary arterial hypertension (IPAH) and 26 healthy controls. One ion (m/z approximately 8600) that was found to be elevated in IPAH was validated by SELDI-TOF MS analysis of a second and separate set of plasma samples comprising 30 IPAH patients and 19 controls. The m/z 8600 was purified from plasma by sequential ion exchange and reverse-phase chromatographies and SDS-PAGE. It was identified, following trypsin digestion, by MS peptide analysis as the complement component, complement 4a (C4a) des Arg. Plasma levels of C4a des Arg measured by ELISA confirmed that the levels were significantly higher (p < 0.0001) in IPAH patients (2.12 +/- 0.27 microg/mL) compared with normal controls (0.53 +/- 0.05 microg/mL). A cut-off level of 0.6 microg/mL correctly classified 92% of IPAH patients and 80% of controls. Further studies will be needed to determine its performance as a diagnostic biomarker, whether used alone or in combination with other biomarkers. Nevertheless, this study demonstrates that putative biomarkers characteristic of IPAH can be identified using a conjoint SELDI-TOF MS - proteomics approach.
Experimental Medicine and Toxicology, Imperial College London, London, UK.
Vahitha B
VB
Abdul-Salam
Gideon A
GA
Paul
J Omar
JO
Ali
Simon R
SR
Gibbs
Dinah
D
Rahman
Graham W
GW
Taylor
Martin R
MR
Wilkins
Robert J
RJ
Edwards
D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D015415:Biomarkers / Q000097:blood; D001798:Blood Proteins / Q000737:chemistry / Q000378:metabolism*; D015934:Complement C4a / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000097:blood*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011651:Pulmonary Artery / Q000378:metabolism / Q000473:pathology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D015415:Biomarkers; D001798:Blood Proteins; C051066:complement C4a, des-Arg; D015934:Complement C4a