Anti-inflammatory Agents and Cholesterol Metabolism

• Difference in expression of the cholesterol-metabolizing enzyme cytochrome P450 cholesterol 27-hydroxylase in peripheral blood mononuclear cells (PBMC) before and after treatment with naprosyn, celecoxib or diclofenac. [ Time Frame: 2 weeks ] [ Designated as safety issue: No ]
  PBMC are isolated directly from patient blood by Ficoll hypaque gradient centrifugation. Total RNA is obtained (TriZol) from PBMC. 27-hydroxylase message is quantitated by quantitative real-time polymerase chain reaction (QRT-PCR) using specific primers.
  
  

• Difference in expression of cholesterol 27-hydroxylase in naive THP-1 human macrophages incubated in plasma from patients obtained before and after treatment with naprosyn, diclofenac or celecoxib. [ Time Frame: 2 weeks ] [ Designated as safety issue: No ]
  Comparison of abundance of the cholesterol-metabolizing enzyme cytochrome P450 cholesterol 27-hydroxylase in the THP-1 human monocyte/macrophage cell line incubated in plasma taken from the same patient before and after treatment with naprosyn, celecoxib or diclofenac. 27-hydroxylase message is quantitated by QRT-PCR and protein by immunoblot.
  
  

Drugs that inhibit cyclooxygenase (COX) are frequently administered to relieve pain and inflammation, but have been associated with cardiovascular (CV) toxicity and an elevated risk of acute myocardial infarction. We have demonstrated that drugs that inhibit the COX-2 isoform act to interfere with cellular cholesterol movement by suppressing expression of proteins that facilitate efflux of cholesterol as well as by enhancing expression of scavenger receptors that mediate cholesterol uptake. We further showed that in cultured THP-1 human macrophages, COX-2 inhibition with drugs (celecoxib, NS398) or by COX-2 RNA silencing leads to foam cell transformation, a critical component of atherogenesis. Thus, COX-2 inhibitors act in a pro-atherogenic fashion on a series of genes which we have named the "Cholesterol Metabolic Signature." Alterations in this signature may contribute to heightened risk of development of atherosclerotic CV disease associated with prolonged use of this drug class. COX enzyme activity supports cholesterol homeostasis through catalysis of prostaglandin (PG) production, and we have shown in vitro that specific subsets of these PGs (PGD2 or PGE2) are sufficient to maintain balance. The aims of this project is: In an observational study of persons with pharmacologic COX-2 selective inhibition (celecoxib) or COX-1/2 inhibition (naproxen, diclofenac), document treatment effects on the Cholesterol Metabolic Signature in isolated subject mononuclear cells and in naïve THP-1 monocytes/macrophages exposed to subject plasma. This will allow detection of variations in degree of pro-atherogenic response of the Cholesterol Metabolic Signature to COX inhibition within human patients that may be associated with a higher likelihood of developing CV sequelae. Understanding the nature of the association between COX inhibition and cholesterol metabolism, and the extent to which they may promote atherosclerotic CV disease, is of critical importance in developing analgesic and anti-inflammatory medications with a more favorable risk profile. The knowledge gained may also improve clinical decision-making by identifying subsets of patients most vulnerable to adverse CV effects of COX inhibition.