Assay for human matrix Gla protein in serum - Potential applications in the cardiovascular field

Matrix Gla protein (MGP) is synthesized in a vitamin K-dependent way in smo oth muscle cells of the healthy vessel wall, and its mRNA transcription is substantially upregulated in atherosclerotic lesions, Here we report the pr eparation of a monoclonal antibody against human MGP and its use in an enzy me-linked immunosorbent assay. The intra-assay and interassay coefficients of variation in serum samples were 5.4% and 12.6%, respectively, and the lo wer detection limit was 8.5% of the normal serum value. Individual within-d ay variations were <11% and did not show a distinct circadian pattern. Day- to-day variations in fasting morning samples were <8%. In a first explorati ve survey, serum MGP concentrations were found to be significantly increase d in patients with severe atherosclerosis, whereas these values were normal in those with low bone mass acid osteoporosis. This finding is consistent with the high MGP mRNA expression observed in atherosclerotic vessels and p laques. More elaborate studies are required to assess the potential clinica l utility of this newly developed assay.