Morphological characteristics of the microvasculature in healing myocardial infarcts

G Ren, LH Michael, ML Entman… - … of Histochemistry & …, 2002 - journals.sagepub.com
G Ren, LH Michael, ML Entman, NG Frangogiannis
Journal of Histochemistry & Cytochemistry, 2002journals.sagepub.com
Myocardial infarction (MI) is associated with an angiogenic response, critical for healing and
cardiac repair. Using a canine model of myocardial ischemia and reperfusion, we examined
the structural characteristics of the evolving microvasculature in healing MI. After 7 days of
reperfusion, the infarcted territory was rich in capillaries and contained enlarged, pericyte-
poor “mother vessels” and endothelial bridges. During scar maturation arteriolar density in
the infarct increased, and a higher percentage of microvessels acquired a pericyte coat …
Myocardial infarction (MI) is associated with an angiogenic response, critical for healing and cardiac repair. Using a canine model of myocardial ischemia and reperfusion, we examined the structural characteristics of the evolving microvasculature in healing MI. After 7 days of reperfusion, the infarcted territory was rich in capillaries and contained enlarged, pericyte-poor “mother vessels” and endothelial bridges. During scar maturation arteriolar density in the infarct increased, and a higher percentage of microvessels acquired a pericyte coat (60.4 ± 6.94% after 28 days of reperfusion vs 30.17 ± 3.65% after 7 days of reperfusion; p<0.05). The microvascular endothelium in the early stages of healing showed intense CD31/PECAM-1 and CD146/Mel-CAM immunoreactivity but weak staining with the Griffonia simplicifolia lectin I (GS-I). In contrast, after 28 days of reperfusion, most infarct microvessels demonstrated significant lectin binding. Our findings suggest that the infarct microvasculature undergoes a transition from an early phase of intense angiogenic activity to a maturation stage associated with pericyte recruitment and formation of a muscular coat. In addition, in the endothelium of infarct microvessels CD31 and CD146 expression appears to precede that of the specific sugar groups that bind the GS-I lectin. Understanding of the mechanisms underlying the formation and remodeling of the microvasculature after MI may be important in designing therapeutic interventions to optimize cardiac repair.
Sage Journals