Adrenomedullin gene transfer induces neointimal apoptosis and inhibits neointimal hyperplasia in injured rat artery.
Arterial wall injury leads to inflammatory reaction and release of growth factors that may mediate intimal regrowth. It is hypothesized that the neointimal cells may originate from adventitial myofibroblasts, medial smooth muscle cells, or differentiated bone marrow derived cells. Adrenomedullin (AM), an auto/paracrine cardiovascular peptide that is secreted from fibroblasts, endothelial cells, and vascular smooth muscle cells, may have a regulatory role in the intimal regeneration. In order to investigate the role of AM in neointimal growth, stimulation of stem cell migration, and apoptosis, we overexpressed AM with recombinant adenovirus in a rat arterial injury model. The intimae were significantly thinner in the arteries treated with AM adenovirus compared to the control group. Intima/media ratios were 0.48 +/- 0.18 and 1.01 +/- 0.20 (P < 0.05) in the AM group and the control group, respectively. In addition, a significantly higher apoptotic index of neointimal cells was seen in the AM gene transfer group compared to the control (2.78 +/- 0.5 vs. 0.57 +/- 0.20, P < 0.01). The neointimal cells stained positive for alpha-smooth muscle actin and negative for desmin suggesting possible myofibroblast origin. Very few c-Kit+ or MDR1+ cells were detected 2 weeks after the injury. We conclude that AM overexpression inhibits neointimal growth. The inhibition is associated with enhanced apoptosis of the neointimal cells which may be of myofibroblast origin.
Rauma-Pinola
Tanja
T
Department of Pharmacology and Toxicology, University of Oulu, Biocenter Oulu, Oulu, Finland.
Pääkkö
Paavo
P
Ilves
Mika
M
Serpi
Raisa
R
Romppanen
Hannu
H
Vuolteenaho
Olli
O
Ruskoaho
Heikki
H
Hautala
Timo
T
D000199:Actins / Q000378:metabolism; D000256:Adenoviridae / Q000235:genetics; D053607:Adrenomedullin; D000818:Animals; D017209:Apoptosis; D001158:Arteries / Q000473:pathology*; D002339:Carotid Arteries / Q000378:metabolism / Q000473:pathology; D003893:Desmin / Q000378:metabolism; D015870:Gene Expression; D006965:Hyperplasia; D008297:Male; D010455:Peptides / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013234:Stem Cells; D014161:Transduction, Genetic; D019076:Transgenes; D017539:Tunica Intima / Q000166:cytology / Q000473:pathology*
D000199:Actins; D053607:Adrenomedullin; D003893:Desmin; D010455:Peptides; C498862:Acta2 protein, rat