Effects of timed administration of doxycycline or methylprednisolone on post-myocardial infarction inflammation and left ventricular remodeling in the rat heart
- 242 Downloads
The development of strategies to ameliorate post-myocardial infarction (MI) remodeling and improve function continues to be an area of clinical importance. Use of steroids for this purpose is controversial since the effects of timed treatment on relevant inflammatory, biochemical and structure/function endpoints are unclear. In a previous report, we demonstrated that use of doxycycline pre-treatment improves post-MI remodeling and passive left ventricular (LV) function. However, the effects of timed doxycyline post-MI treatment are unknown. To examine these issues, we performed a study using a rat MI model. Animals were administered one of the following: doxycycline (DOX), the corticosteroid methylprednisolone (MP), or aqueous vehicle. Treatment was given early, short-term (at time of MI to 24 h post-MI) or late, long term (2–7 days post-MI). Animals were sacrificed at 3, 7 or 42 days post-surgery. We assessed LV hemodynamics, pressure–volume, and pressure–scar strains, histomorphometry, inflammation via measurements of myeloperoxidase activity, and matrix metalloproteinase (MMP) activity. Late MP treatment yielded a robust right-shifted pressure–volume curve, which was accompanied by increased scar strains. Late DOX treatment yielded reduced average heart weight and size and preserved scar thickness. DOX treatment did not suppress inflammation, which contrasts with the suppressive effects of MP. Use of early or late MP yielded increased MMP activity in infarcted and non-infarcted regions. Early and late treatment with DOX yielded infarct–associated MMP activity levels comparable to those of vehicle–treated animals. In conclusion, results indicate that late use of MP yields adverse post-MI structure/function outcomes that correlate with suppression of inflammation and increased MMP activity. These observations contrast with those of DOX, in particular, late treatment where improved outcomes were observed in LV structure and were accompanied by the lack of suppression of inflammation.
KeywordsLeft Ventricular Pressure Late Treatment Infarcted Wall Adverse Left Ventricular Remodel Scar Region
This study was supported by NIH grants HL-43617 to Dr. F. Villarreal and HL-07444 to Dr. R. Garcia. We thank Dr. Paul Juneau for his insightful review of statistical analyses used in this report.
- 11.Hafezi-Moghadam A, Simoncini T, Yang Z, Limbourg FP, Plumier JC, Rebsamen MC, Hsieh CM, Chui DS, Thomas KL, Prorock AJ, Laubach VE, Moskowitz MA, French BA, Ley K, Liao JK (2002) Acute cardiovascular protective effects of corticosteroids are mediated by non-transcriptional activation of endothelial nitric oxide synthase. Nat Med 8:473–9PubMedCrossRefGoogle Scholar
- 14.Entman ML, Youker KA, Frangogiannis N, Lakshminarayanan V, Nossuli T, Evans A, Kurrelmeyer K, Mann DL, Smith CW (2000) Is inflammation good for the ischemic heart–perspectives beyond the ordinary. Z Kardiol 89 Suppl 9:IX/82–7Google Scholar
- 25.Scarabelli TM, Stephanou A, Pasini E, Gitti G, Townsend P, Lawrence K, Chen-Scarabelli C, Saravolatz L, Latchman D, Knight R, Gardin J (2004) Minocycline inhibits caspase activation and reactivation, increases the ratio of XIAP to smac/DIABLO, and reduces the mitochondrial leakage of cytochrome C and smac/DIABLO. J Am Coll Cardiol 43:865–74PubMedCrossRefGoogle Scholar
- 27.Sawicki G, Leon H, Sawicka J, Sariahmetoglu M, Schulze CJ, Scott PG, Szczesna-Cordary D, Schulz R (2005) Degradation of myosin light chain in isolated rat hearts subjected to ischemia-reperfusion injury: a new intracellular target for matrix metalloproteinase-2. Circulation 112:544–52PubMedCrossRefGoogle Scholar