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Enhanced phospholipase A2 and C activities of peripheral blood polymorphonuclear leukocytes from patients with
Abstract:
Increased concentrations of eicosanoids are found in synovial fluids (SF) from patients with rheumatoid arthritis (RA). SF polymorphonuclear leukocytes (PMN), which derive from peripheral blood, usually account for approximately 90% of the cells in RA SF. Since eicosanoid precursor fatty acids (FA) are liberated by phospholipases from membrane phospholipids, we examined phospholipase A2 and C activities in peripheral blood PMN from patients with RA. Peripheral blood PMN from patients with RA (RA-PMN) exhibit greater phospholipase A2 activities against phosphatidylcholine (PC) and phosphatidylethanolamine (PE), and greater phospholipase C activities against PC, PE, and phosphatidylinositol (PI) than PMN obtained from normal volunteers (N-PMN).
Insights
Rheumatoid arthritis patients
Area of Science:
- Biochemistry
- Immunology
- Rheumatology
Background:
- Elevated eicosanoid levels are characteristic of rheumatoid arthritis synovial fluid.
- Polymorphonuclear leukocytes (PMN) constitute approximately 90% of cells in rheumatoid arthritis synovial fluid.
- Eicosanoid precursor fatty acids are released by phospholipases from membrane phospholipids.
Purpose of the Study:
- To investigate phospholipase A2 and C activities in peripheral blood PMN from rheumatoid arthritis patients.
Main Methods:
- Collected peripheral blood PMN from rheumatoid arthritis patients and normal volunteers.
- Assayed phospholipase A2 and C activities in PMN using various phospholipid substrates.
Main Results:
- Rheumatoid arthritis PMN (RA-PMN) demonstrated significantly higher phospholipase A2 activity against phosphatidylcholine (PC) and phosphatidylethanolamine (PE) compared to normal PMN (N-PMN).
- RA-PMN also exhibited greater phospholipase C activity against PC, PE, and phosphatidylinositol (PI) than N-PMN.
Conclusions:
- Peripheral blood PMN in rheumatoid arthritis patients display enhanced phospholipase A2 and C activities.
- These heightened enzymatic activities may contribute to increased eicosanoid production in rheumatoid arthritis.