Molecular evidence for induction of intracellular adhesion molecule-1 in the viable border zone associated with ischemia-reperfusion injury of the dog heart.

Abstract

BACKGROUND Acute inflammation may play a role in injury during reperfusion following myocardial ischemia. Studies in vitro suggest that intracellular adhesion molecule-1 (ICAM-1) mediates neutrophil adherence to cardiac myocytes and neutrophil-mediated injury. We have shown cytokine activity in postischemic cardiac lymph sufficient to maximally express ICAM-1 on myocytes and that ICAM-1 mRNA is found in the previously ischemic myocardium early in reperfusion. METHODS AND RESULTS In the present study, we used in situ hybridization techniques to detect ICAM-1 mRNA and examine the cells of origin, relation to cell injury, and relation to inflammatory infiltration after 1 hour of ischemia and varying times of reperfusion. By 1 hour of reperfusion, ICAM-1 mRNA was detected in much of the ischemic myocardium, except in areas of contraction band necrosis. At 2 and 3 hours, a clear demarcation of necrotic areas surrounding ischemic areas of viable myocardium with ICAM-1 mRNA staining was present, and ICAM-1 mRNA staining increased with time. Nonischemic areas had no visible ICAM-1 mRNA staining in the first 3 hours. By 24 hours of reperfusion, ICAM-1 mRNA was present in both control and ischemic segments (excluding the necrotic areas) compatible with a generalized circulation of cytokines persistent at 24 hours. In the absence of reperfusion, ICAM-1 mRNA staining was not seen in the first 3 hours and was markedly reduced at 24 hours. The interface of viable and necrotic cells also contained the most extensive inflammatory infiltration. CONCLUSIONS Evidence is presented that induction of ICAM-1 mRNA has highly specific localization to ischemic but viable myocardium. Induction of ICAM-1 mRNA transcription in early reperfusion may render the viable "border zone" susceptible to neutrophil-induced injury.

Glucocorticoid Treatment Prevents Progressive Myocardial Dysfunction Resulting From Experimental Coronary Microembolization

“…However, when administered 30 minutes after established coronary microembolization, methylprednisolone no longer prevented leukocyte infiltration, possibly because initial steps of leukocyte activation and leukocyte/endothelium interaction had already occurred. 31,35,36 Glucocorticoids have previously been shown to inhibit the expression of TNF-␣ mRNA in immunologically activated rat peritoneal mast cells, 16 to suppress the production of TNF-␣ in serum and myocardium of lipopolysaccharidestimulated rats, 17 and to abolish the release of TNF-␣ into serum of humans during cardiac surgery. 15 Glucocorticoids also attenuate the infiltration of TNF-␣-producing macrophages/monocytes after coronary microembolization in pigs.…”

Roles and Relationship of Macrophages and Monocyte Chemotactic and Activating Factor/Monocyte Chemoattractant Protein-1 in the Ischemic and Reperfused Rat Heart

“…Histopathologically, it has been shown that neutrophils first penetrate the infarcted myocardium, followed by macrophages, and it has been reported that neutrophils are associated with reperfusion injury, in concert with the induction of intracellular adhesion molecule-1 (ICAM-1), interleukin (IL)-6, or IL-8 (Hawkins et al, 1996;Kukielka et al, 1993Kukielka et al, , 1995aKukielka et al, , 1995bNeumann et al, 1995;Youker et al, 1994). It has also been reported that reperfusion is associated with an increase in the number of macrophages compared with the nonreperfused Mean number of macrophages in the hearts at 1 hour, 3 hours, and 6 hours after reperfusion (R).…”

Cardiac Myocytes Produce Interleukin-6 in Culture and in Viable Border Zone of Reperfused Infarctions

“…At the end of the reperfusion period, the heart was stopped by infusion of saturated potassium chloride and removed immediately and processed for RNA isolation or immunohistochemistry and in situ hybridization as previously described. 20,22 Adjacent sections were used for blood flow determination with radiolabeled microspheres as previously described. 26,27 Analysis of RNA, blood flow determination, and histopathology were performed independently in different laboratories and in a blinded fashion.…”

“…20 Digoxigenin-labeled probes were prepared by in vitro transcription from a linearized template with the Genius RNA probe labeling kit (Boehringer Mannheim Corp) according to the manufacturer's instructions. A 215-bp [bases 483 to 697 of the published sequence 22 ] fragment of canine IL-6 cDNA was obtained with polymerase chain reaction amplification and was subcloned into the polymerase chain reaction plasmid (Invitrogen) so that the use of SP6 polymerase would result in the generation of single-stranded antisense (3Ј-5Ј) and the use of T7 polymerase would result in the generation of the sense (5Ј-3Ј) probe.…”

“…For the ICAM-1 probe, a 150-bp fragment was subcloned in both orientations into PBluescript II Skϩ and PGEM-3 so that use of T7 polymerase would result in the generation of single-stranded antisense (3Ј-5Ј) and of the sense (5Ј-3Ј) probe. 20 The procedure was the same as described above for the IL-6 riboprobe.…”