Increased expression of a disintegrin and metalloproteinase thrombospondin 1 in thrombosed hemodialysis grafts.

PURPOSE: To use proteomic analysis to identify upregulated and downregulated proteins in thrombosed hemodialysis graft specimens. One of these significantly upregulated proteins was a disintegrin and metalloproteinase thrombospondin-1 (ADAMTS-1), and its expression and activity were determined in thrombosed hemodialysis grafts.
MATERIALS AND METHODS: Hemodialysis vascular access samples (thrombosed veins, n = 8; control veins, n = 6) were obtained from patients who required surgical revision. Proteomic analysis was performed with isotope-coded affinity tag labeling with multidimensional liquid chromatography followed by tandem mass spectrometry on four thrombosed hemodialysis graft specimens with control veins. Expression of ADAMTS-1 was confirmed by performing immunoprecipitation followed by Western blot analysis. Finally, immunohistochemistry was used to localize expression in a separate group of patients with thrombosed grafts.
RESULTS: Thirty-nine unique proteins were common to all four patients. ADAMTS-1 was one of the only significantly upregulated protein (>38 fold). ADAMTS-1 expression was confirmed by performing immunoprecipitation and Western blot analysis and was significantly increased. ADAMTS-1 expression was localized to adventitial macrophages and neutrophils of thrombosed grafts.
CONCLUSIONS: ADAMTS-1 was significantly upregulated in thrombosed hemodialysis grafts by mass spectrometric analysis and Western blot analysis. Expression was localized to adventitial macrophages and leukocytes. It is hypothesized that ADAMTS-1 may be related to intimal hyperplasia in hemodialysis vascular access grafts. Future work is planned on inhibiting ADAMTS-1 expression and determining the effect on intimal hyperplasia in hemodialysis grafts.