alpha-actin isoform distribution in normal and failing human heart: a morphological, morphometric, and biochemical study:a morphological, morphometric, and biochemical study

We investigated the distribution of alpha-skeletal, alpha-cardiac, and alpha-smooth muscle actin isoforms in human heart during development, hypertrophy, and failure. At 20 weeks of fetal life, alpha-skeletal actin was localized in a small proportion of subendocardial and papillary muscle cardiomyocytes. At this gestation time, diffuse alpha-cardiac actin staining was observed, associated with focal expression of alpha-smooth muscle actin. In normal adult subjects, alpha-skeletal actin positive cardiomyocytes were distributed in a transmural gradient with the highest proportion located subendocardially. In myocardial hypertrophy and cardiomyopathies, the amount of alpha-skeletal actin was increased and diffuse staining was seen in all layers of ventricular myocardium, with the exception of idiopathic dilated cardiomyopathies. Cardiomyocytes were negative for of-smooth muscle actin in all pathological situations studied. As expected, fibroblasts in post-infarct scars expressed of smooth muscle actin and transforming growth factor-beta1 but, surprisingly, were negative for these proteins in interstitial fibrosis. Our results demonstrate that increased expression of alpha-skeletal actin in the diseased human heart is associated with increased myocyte stretch, increased wall stress, and pressure overload, but not with idiopathic dilated cardiomyopathies. They also suggest that fibrotic changes develop with different mechanisms in scars versus interstitial fibrosis. Copyright (C) 2003 John Wiley Sons, Ltd

Evidence of a topographical link between unstable carotid plaques and luminal stenosis: can we better stratify asymptomatic patients with significant plaque burden?

[No abstract available

Plasma levels of metalloproteinases-3 and -9 as markers of successful abdominal aortic aneurysm exclusion after endovascular graft treatment

BACKGROUND: Structural alterations of aortic wall resulting from degradation of matrix proteins by matrix metalloproteinases (MMPs) characterize abdominal aortic aneurysms (AAAs). No studies have compared circulating levels of MMPs after endovascular graft (EVG) exclusion in comparison with open surgical repair (OSR) in patients affected by AAA. METHODS AND RESULTS: An abdominal angiography and CT scan were performed in all patients at the time of enrollment. A spiral CT scan was performed at 6 months to detect presence of endoleaks. MMP-3 and MMP-9 levels were measured before EVG (n=30) and OSR (n=15) treatments and at 1, 3, and 6 months of follow-up by a sandwich ELISA technique. Healthy volunteers (n=10) were used as control subjects. Immunohistochemical staining for MMP-9 and MMP-3 was performed on tissue samples from surgical cases. Both MMP-9 and MMP-3 mean basal levels were significantly higher in patients affected by AAA than in control subjects (32.3+/-20.7 ng/mL for EVG and 28+/-9.9 ng/mL for OSR versus 8.9+/-2.5 ng/mL, 2P<0.05; 18.3+/-9.7 ng/mL and 26.7+/-10.8 ng/mL versus 8.2+/-5.3 ng/mL, 2P<0.001). In the OSR group, both MMP-9 and MMP-3 mean levels decreased after surgery (28+/-9.9 ng/mL at basal versus 14.7+/-6.6 ng/mL at 6 months, 2P<0.001; 26.7+/-10.8 versus 12+/-5.3 ng/mL; 2P<0.001). In the EVG group, a statistically significant difference at 6-month follow-up in MMP-9 and MMP-3 mean plasma values was detected in patients who had endoleakage in comparison with patients without endoleakage (44.3+/-20.7 versus 14.6+/-7.0 ng/mL, 2P<0.005; 25+/-11.5 versus 10.3+/-5.4 ng/mL, 2P<0.005). CONCLUSIONS: After EVG exclusion, MMP-9 and MMP-3 levels decreased to a level similar to that of patients undergoing OSR. In addition, a lack of decrease in MMP levels after EVG exclusion may help in identifying patients who will have endoleakage and consequent aneurysm expansion caused by continuous sac pressurization during follow-up