Adenosine is a short-acting coronary vasodilator, and it is widely used during pharmacological stress myocardial perfusion imaging. It has a well-established safety profile, and most of its side effects are known to be mild and transient. Until now, coronary vasospasm has been rarely reported as a side effect of adenosine during or after adenosine stress test. This study reports a case of coronary vasospasm which was documented on stress myocardial perfusion CT imaging during adenosine stress test.
Adenosine/*adverse effects/metabolism ; Aged ; Coronary Vasospasm/*chemically induced/pathology ; Humans ; Male ; Myocardial Perfusion Imaging/*methods ; Sensitivity and Specificity ; Tomography, X-Ray Computed/*methods ; Vasodilator Agents/*adverse effects/metabolism

OBJECTIVETo investigate the effects of several vasoactive peptides on the development of arterial restenosis after balloon angioplasty.

METHODSIn rat aortic artery restenosis model produced by denudation of aortic endothelia, we observed changes of endothelin (ET), angiotensin II (AII), calcitonin gene-related peptide (CGRP) and adrenomedullin (Adm) in plasma and aorta with radioimmunoassay and expression of hypertension-related gene (HRG-1) with semi-quantitative RT-PCR, and studied the effects of these peptides on intimal hyperplasia, intima/media ratio and MAPK activities of aortic artery after angioplasty respectively. Furthermore, in cultured cells, we studied the effects of these peptides on vascular smooth muscle cell (VSMC) proliferation and expression of HRG-1 of VSMC from spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats with 3H-TdR incorporation and RT-PCR respectively.

RESULTSAfter angioplasty, the levels of ET and AII in plasma and aorta significantly increased, accompanied with VSMC proliferation and neointima hyperplasia. On day 10 after angioplasty, the levels of ET in plasma and aorta increased by 69% and 124% respectively, compared with sham group (P < 0.01); and the level of aortic AII increased by 80% (P < 0.01). Antiserum against ET or inhibitors of angiotensin converting enzyme (ACE) could significantly inhibit the proliferation of VSMC and neointima formation. Compared with the sham group, on day 3 after angioplasty, the CGRP levels in plasma and aorta increased by 64% and 89% respectively (P < 0.01) and the Adm levels in plasma and tissue increased by 129% and 102% respectively (P < 0.01). On day 10, intravenous administration of CGRP significantly inhibited the proliferation of VSMC and neointima formation induced by balloon aortic injury (by 66% and 79% respectively, P < 0.01). In addition, ET and AII attenuated the expression of HRG-1 in aorta and stimulated mitogen-activated protein kinase (MAPK) activity, while CGRP and Adm potentiated the expression of HRG-1 and inhibited MAPK.

CONCLUSIONSET and AII can stimulate the proliferation of injured intima while CGRP and Adm have an anti-hyperplasia effect after angioplasty. These 4 peptides are involved in the regulation of VSMC proliferation and affect the development of vascular restenosis by regulating the expression of HRG-1 and MAPK activity.

Adrenomedullin ; Angioplasty, Balloon ; adverse effects ; Angiotensin II ; pharmacology ; therapeutic use ; Animals ; Aorta, Thoracic ; cytology ; metabolism ; Calcitonin Gene-Related Peptide ; pharmacology ; therapeutic use ; Cell Division ; drug effects ; Cells, Cultured ; Coronary Restenosis ; etiology ; metabolism ; Endothelin-1 ; pharmacology ; therapeutic use ; Male ; Mitogen-Activated Protein Kinases ; metabolism ; Muscle, Smooth, Vascular ; cytology ; Peptides ; pharmacology ; therapeutic use ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Rats, Wistar ; Vasodilator Agents ; pharmacology ; therapeutic use