Evidence of woven bone formation in carotid artery plaques

Abstract

Objective: Plaque morphology plays an important prognostic role in the occurrence of cerebrovascular events. Echolucent and heterogeneous plaques, in particular, carry an increased risk of subsequent stroke. Depending on the quality of the plaque echogenicity based on B-mode ultrasound examination, carotid plaques divide into a soft lipid-rich plaque and a hard plaque with calcification. The aim of this study was to investigate structural changes in the basement membrane of different carotid artery plaque types. Patients and methods: Biopsies were taken from 10 male patients (average age; 75 + 1 years) and 7 females (68 + 3 years). The study population included patients suffering from a filiform stenosis of the carotid artery, 8 patients with acute cerebrovascular events and 9 with asymptomatic stenosis. Scanning electron and polarised light microscopic investigations were carried out on explanted plaques to determine the morphology of calcified areas in vascular lesions. Results: By means of scanning electron microscopy, multiple foci of local calcification were identified. The endothelial layer was partially desquamated from the basement membrane and showed island-like formations. Polarised light microscopy allows us to distinguish between soft plaques with transparent structure and hard plaques with woven bone formation. Conclusion: The major finding of our study is the presence of woven bone tissue in hard plaques of carotid arteries, which may result from pathological strains or mechanical overloading of the collagen fibers. These data suggest a certain parallel with sclerosis of human aortic valves due to their similar morphological characteristics.

Scanning Electron Microscopic Investigations to Clarify the Role Played by the Endocardium in the Origin of Dilated Cardiomyopathy(DCM)

“…The collagen fibers are hypertrophied and have lost their helical structure. In addition, lamellar Lambl` excrecences which we have been able to demonstrate in a similar form in degenerated aortic and mitral valves [24] are frequent, Craterlike defects of the endothelium have rarely been observed. On the other hand, we were able to detect fungal micelle-like strictures in all examined tissues, which mainly occurred at the edge of severely destroyed mycardium.…”

“…In the myocardium of DCM, we were able to detect two differing findings. On the one hand, there are changes in the endothelium and the extracellular matrix, which we know in a very similar form from aortic and mitral valves explanted due to degeneration [24]. On the one hand, there is a desquamation of the endothelial cells, which lose their junctions to each other.…”

What Do the Heart Valves Tell Us?

“…Steiner ve ark. 'nın yaptığı çalışmada cerrahi olarak eksize edilen 1177 kalp kapağının his-tolo¬jik incelenmesinde yaklaşık % 11 oranında kemik ve/veya kartilaj formasyonu izlemişlerdir (7,8). Kalsifiye kapaklardaki kıkırdak oluşumunun, kemikte kırık iyileşmesinde görülene benzer şekilde endokondral ossifikasyon ile devamlılık gösterdiği saptanmıştır (9,10).…”

"Changes of the Endothelium and Extracellular Matrix in Thoracic Aortic Aneurysm Revealed by Scanning Electron Microscopic Investigations Are there Structural Parallels to Aortic Valve Degeneration?"

“…The synthesis of other chains of collagen, discussed already in the degeneration of aortic and mitral valves is a sign of overloading of the collagen fibers as primary stimuli [27]. Toumpoulis et al demonstrate that increased collagen alpha 1 (XI) and V collagen mRNA and protein levels are linearly correlated with the size of the aneurysm and provide a potential mechanism for generation and progression of aneurysmal enlargement [28].…”