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Prevention of Coronary Vascular Abnormalities Early in Reperfusion with TGF-β May Not Prevent Late Coronary Vascular Injury
Journal article   Open access   Peer reviewed

Prevention of Coronary Vascular Abnormalities Early in Reperfusion with TGF-β May Not Prevent Late Coronary Vascular Injury

Mark Keller, Yinong Kong, Alistair Robertson and Lawrence Horwitz
Journal of cardiovascular pharmacology, Vol.30(2), pp.197-204
08/1997
DOI: 10.1097/00005344-199708000-00008
PMID: 9269947
url
https://doi.org/10.1097/00005344-199708000-00008View
Published (Version of record) Open Access

Abstract

Endothelial injury, manifest by increased protein leak and decreased endothelium-dependent relaxation, occurs during reperfusion after ischemia. Transforming growth factor-β (TGF-β) has been shown to improve endothelium-dependent relaxation and reduce infarct size after short periods (from 20 min to 4.5 h) of reperfusion even when administered 24 h before the ischemic period. However, whether this represents a transient delay in the process leading to endothelial injury or prevention of injury has not been clear. To examine this issue, we measured protein leak, an index of coronary microvascular permeability, and endothelium-dependent relaxation, a measure of coronary endothelial function, after brief (1-h) and lengthy (48-h) reperfusion periods in dogs treated 30 min before ischemia with TGF-β (30 μg/kg, i.v.) and control dogs. The left anterior descending coronary artery (LAD) was ligated for 1 h followed by 1 h of reperfusion (n = 10) or 48 h of reperfusion (n = 12). Protein leak was assessed by a dual-isotope technique by using radiolabeled transferrin and erythrocytes, and endothelium-dependent relaxation was assessed in epicardial coronary rings by using adenosine diphosphate (ADP), an endothelium-dependent vasodilator, and sodium nitroprusside (SNP), an endothelium-independent dilator. In control animals, there was a marked increase in the protein leak index (PLI) in the infarct zone (8.3 ± 1.4 in 1-h dogs, and 8.7 ± 0.9 in 48-h dogs) compared with the nonischemic myocardium (3.1 ± 0.8 at 1 h, and 3.8 ± 0.9 at 48 h). In TGF-β treated dogs, there was a marked improvement in PLI in the infarct zone in 1-h dogs (PLI, 4.1 ± 1.1; p < 0.05; or a 50% reduction compared with untreated dogs). However, the 48-h dogs treated with TGF-β failed to demonstrate an improvement in PLI (PLI, 8.5 ± 0.9; p = NS). Endothelium-dependent relaxation was impaired in the LAD in control dogs, and treatment with TGF-β failed to improve relaxation after 1 or 48 h of reperfusion. Microvascular permeability was increased and endothelium-dependent relaxation was decreased after ischemia at both 1 and 48 h of reperfusion. Pretreatment with TGF-β reduced the increase in permeability at 1 h of reperfusion but not at 48 h.

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