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Cyclooxygenases, thromboxane, and atherosclerosis: plaque destabilization by cyclooxygenase-2 inhibition combined with thromboxane receptor antagonism.
Circulation. 2005 Jan 25; 111(3):334-42.Circ

Abstract

BACKGROUND

Antagonism or deletion of the receptor (the TP) for the cyclooxygenase (COX) product thromboxane (Tx)A2, retards atherogenesis in apolipoprotein E knockout (ApoE KO) mice. Although inhibition or deletion of COX-1 retards atherogenesis in ApoE and LDL receptor (LDLR) KOs, the role of COX-2 in atherogenesis remains controversial. Other products of COX-2, such as prostaglandin (PG) I2 and PGE2, may both promote inflammation and restrain the effects of TxA2. Thus, combination with a TP antagonist might reveal an antiinflammatory effect of a COX-2 inhibitor in this disease. We addressed this issue and the role of TxA2 in the promotion and regression of diffuse, established atherosclerosis in Apobec-1/LDLR double KOs (DKOs).

METHODS AND RESULTS

TP antagonism with S18886, but not combined inhibition of COX-1 and COX-2 with indomethacin or selective inhibition of COX-2 with Merck Frosst (MF) tricyclic, retards significantly atherogenesis in DKOs. Although indomethacin depressed urinary excretion of major metabolites of both TxA2, 2,3-dinor TxB2 (Tx-M), and PGI2, 2,3-dinor 6-keto PGF(1alpha) (PGI-M), only PGI-M was depressed by the COX-2 inhibitor. None of the treatments modified significantly the increase in lipid peroxidation during atherogenesis, reflected by urinary 8,12-iso-iPF(2alpha)-VI. Combination with the COX-2 inhibitor failed to augment the impact of TP antagonism alone on lesion area. Rather, analysis of plaque morphology reflected changes consistent with destabilization of the lesion coincident with augmented formation of TxA2. Despite a marked effect on disease progression, TP antagonism failed to induce regression of established atherosclerotic disease in this model.

CONCLUSIONS

TP antagonism is more effective than combined inhibition of COX-1 and COX-2 in retarding atherogenesis in Apobec-1/LDLR DKO mice, which perhaps reflects activation of the receptor by multiple ligands during disease initiation and early progression. Despite early intervention, selective inhibition of COX-2, alone or in combination with a TP antagonist, failed to modify disease progression but may undermine plaque stability when combined with the antagonist. TP antagonism failed to induce regression of established atherosclerotic disease. TP ligands, including COX-1 (but not COX-2)-derived TxA2, promote initiation and early progression of atherogenesis in Apobec-1/LDLR DKOs but appear unimportant in the maintenance of established disease.

Authors+Show Affiliations

Institute for Translational Medicine and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

15655126

Citation

Egan, Karine M., et al. "Cyclooxygenases, Thromboxane, and Atherosclerosis: Plaque Destabilization By Cyclooxygenase-2 Inhibition Combined With Thromboxane Receptor Antagonism." Circulation, vol. 111, no. 3, 2005, pp. 334-42.
Egan KM, Wang M, Fries S, et al. Cyclooxygenases, thromboxane, and atherosclerosis: plaque destabilization by cyclooxygenase-2 inhibition combined with thromboxane receptor antagonism. Circulation. 2005;111(3):334-42.
Egan, K. M., Wang, M., Fries, S., Lucitt, M. B., Zukas, A. M., Puré, E., Lawson, J. A., & FitzGerald, G. A. (2005). Cyclooxygenases, thromboxane, and atherosclerosis: plaque destabilization by cyclooxygenase-2 inhibition combined with thromboxane receptor antagonism. Circulation, 111(3), 334-42.
Egan KM, et al. Cyclooxygenases, Thromboxane, and Atherosclerosis: Plaque Destabilization By Cyclooxygenase-2 Inhibition Combined With Thromboxane Receptor Antagonism. Circulation. 2005 Jan 25;111(3):334-42. PubMed PMID: 15655126.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cyclooxygenases, thromboxane, and atherosclerosis: plaque destabilization by cyclooxygenase-2 inhibition combined with thromboxane receptor antagonism. AU - Egan,Karine M, AU - Wang,Miao, AU - Fries,Susanne, AU - Lucitt,Margaret B, AU - Zukas,Alicia M, AU - Puré,Ellen, AU - Lawson,John A, AU - FitzGerald,Garret A, Y1 - 2005/01/17/ PY - 2005/1/19/pubmed PY - 2005/6/23/medline PY - 2005/1/19/entrez SP - 334 EP - 42 JF - Circulation JO - Circulation VL - 111 IS - 3 N2 - BACKGROUND: Antagonism or deletion of the receptor (the TP) for the cyclooxygenase (COX) product thromboxane (Tx)A2, retards atherogenesis in apolipoprotein E knockout (ApoE KO) mice. Although inhibition or deletion of COX-1 retards atherogenesis in ApoE and LDL receptor (LDLR) KOs, the role of COX-2 in atherogenesis remains controversial. Other products of COX-2, such as prostaglandin (PG) I2 and PGE2, may both promote inflammation and restrain the effects of TxA2. Thus, combination with a TP antagonist might reveal an antiinflammatory effect of a COX-2 inhibitor in this disease. We addressed this issue and the role of TxA2 in the promotion and regression of diffuse, established atherosclerosis in Apobec-1/LDLR double KOs (DKOs). METHODS AND RESULTS: TP antagonism with S18886, but not combined inhibition of COX-1 and COX-2 with indomethacin or selective inhibition of COX-2 with Merck Frosst (MF) tricyclic, retards significantly atherogenesis in DKOs. Although indomethacin depressed urinary excretion of major metabolites of both TxA2, 2,3-dinor TxB2 (Tx-M), and PGI2, 2,3-dinor 6-keto PGF(1alpha) (PGI-M), only PGI-M was depressed by the COX-2 inhibitor. None of the treatments modified significantly the increase in lipid peroxidation during atherogenesis, reflected by urinary 8,12-iso-iPF(2alpha)-VI. Combination with the COX-2 inhibitor failed to augment the impact of TP antagonism alone on lesion area. Rather, analysis of plaque morphology reflected changes consistent with destabilization of the lesion coincident with augmented formation of TxA2. Despite a marked effect on disease progression, TP antagonism failed to induce regression of established atherosclerotic disease in this model. CONCLUSIONS: TP antagonism is more effective than combined inhibition of COX-1 and COX-2 in retarding atherogenesis in Apobec-1/LDLR DKO mice, which perhaps reflects activation of the receptor by multiple ligands during disease initiation and early progression. Despite early intervention, selective inhibition of COX-2, alone or in combination with a TP antagonist, failed to modify disease progression but may undermine plaque stability when combined with the antagonist. TP antagonism failed to induce regression of established atherosclerotic disease. TP ligands, including COX-1 (but not COX-2)-derived TxA2, promote initiation and early progression of atherogenesis in Apobec-1/LDLR DKOs but appear unimportant in the maintenance of established disease. SN - 1524-4539 UR - https://www.unboundmedicine.com/medline/citation/15655126/Cyclooxygenases_thromboxane_and_atherosclerosis:_plaque_destabilization_by_cyclooxygenase_2_inhibition_combined_with_thromboxane_receptor_antagonism_ L2 - http://www.ahajournals.org/doi/full/10.1161/01.CIR.0000153386.95356.78?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -