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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Arthritis, Rheumatoid, Blotting, Western, Cells, Cultured, Collagenases, Electrophoresis, Polyacrylamide Gel, Endothelium, Enzyme-Linked Immunosorbent Assay, Gelatinases, Humans, Matrix Metalloproteinase 1, Matrix Metalloproteinase 2, Matrix Metalloproteinase 9, Metalloendopeptidases, Skin, Spectrophotometry, Synovial Membrane, Tetradecanoylphorbol Acetate, Tissue Inhibitor of Metalloproteinase-1.
user
Do rheumatoid synovial endothelial cells secrete decreased levels of tissue inhibitor of MMP ( TIMP1 )? Context: Angiogenesis (the formation of new blood vessels) is a major component of the inflammatory pannus in rheumatoid arthritis (RA). Matrix metalloproteinase (MMP) secretion by microvascular endothelial cells is an essential step in angiogenesis. The secretion of MMP1, MMP2, MMP9, and TIMP1 by human microvascular endothelial cells derived from RA synovium (RASE) to normal synovium (NSE) and neonatal foreskin (FSE) was compared. Confluent monolayers of endothelial cells in basal medium were pre-incubated for 24 hours in the presence or absence of phorbol myristate acetate (PMA, 100 ng/ml). MMP1 activity was measured using a spectrophotometric assay and western blotting. MMP2 and MMP9 were measured using zymography. TIMP1 was measured by enzyme linked immunosorbent assay and western blotting. There was little difference between the amounts of MMP2 secreted by any of the cell lines. In response to PMA both synovial cell types showed a significantly higher MMP1 and MMP9 activity compared with FSE, although there was no difference between RASE and NSE. Tumour necrosis factor alpha had minimal effect on MMP activity. There was a striking decrease in the amount of TIMP1 secreted by RASE compared with normal synovium.
assistant
As overall MMP activity is a balance between the amount of MMP and TIMP1 present, the low levels of TIMP1 produced by RASE would shift the balance in favour of increased MMP activity by these cells. This is likely to contribute to the angiogenic potential of RASE. Final Decision: yes