New collateral flow increasing early after coronary occlusion prevented myocardial necrosis in dogs

Abstract

Increases in regional myocardial blood flow (Qm) developing soon after myocardial infarction may minimize myocardial necrosis. To test this hypothesis, Qm in the area surrounding an acutely occluded coronary artery was determined successively over 4 weeks in 11 dogs. Non-radioactive colored microspheres were injected into the left atrium 5 s (Qm at this time is referred to as Q1), 3 h (Q2), 12 h (Q3), and 4 weeks (Q4) after occlusion of the coronary artery. After termination of the experiment, the heart was removed, and Qm and three indices of myocardial necrosis i.e., myocardial creatine kinase activity (CK), infarct size determined by triphenyl tetrazolium chloride stain (TTC), and myocardial fibrosis visualized by Azan-Mallory stain, were determined. Each Qm was expressed as a percentage of normal: Qm (% of normal) = [Q/Qc] ischemic area/[Q'/Qc']non-ischemic area x 100, where Qc indicates Qm determined before coronary occlusion. In the ischemic area of the left ventricle, Q1, Q2, Q3, and Q4 were 25 +/- 3%, 30 +/- 3%, 31 +/- 3%, and 42 +/- 3% of normal, respectively, in the inner layer, and 31 +/- 3%, 52 +/- 4%, 52 +/- 4%, and 77 +/- 6% of normal, respectively, in the outer layers. During the 4-week period, the increase of Qm in the outer layer was greater than that in the inner layer. The inner layer showed a small increase of flow from Q3 to Q4 (9 +/- 2%), but in the outer layer there were greater flow increases from Q1 to Q2 (21 +/- 3%) and from Q3 to Q4 (24 +/- 6%).(ABSTRACT TRUNCATED AT 250 WORDS)

Intramyocardial sustained delivery of basic fibroblast growth factor improves angiogenesis and ventricular function in a rat infarct model

“…2,[11][12][13] However, these therapies have many new and presently unsolved issues such as choice of drug delivery system, route of administration, and sideeffect profiles. Given that the therapeutic approach to induction of angiogenesis uses highly potent angiogenic growth factors that may have grave side effects, a high drug target level and low systemic exposure should be the ultimate goal.…”

Development and Evaluation of a New Canine Myocardial Infarction Model Using a Closed-Chest Injection of Thrombogenic Material

“…The sections were stained with hematoxylin (Sigma) and eosin (Sigma) and by the Azan-Mallory staining method. 8 Collagen fiber was designated as the area that stained blue using the Azan-Mallory staining method.…”