Distribution of Hyaluronan and Dermatan/Chondroitin Sulfate Proteoglycans in Human Aortic Dissection

Abstract

Aortic dissections (AD) are characterized by the separation of the artery into two sheets, possibly due to fragility of the vessel wall. A mucoid histological pattern, imparted to the tissues mainly by hyaluronan and proteoglycans, can be seen in "cysts" and, in chronic cases, in a band of repair tissue. We studied the localization of hyaluronan, versican, decorin and biglycan in situ in aortas of 21 patients with recent AD, 8 with chronic AD and in 15 control cases. None of these substances was increased in the areas of mucoid "cysts" that possibly contain anomalous material. Similar distributions were seen in normal and dissected aortas: versican and hyaluronan were more prominent in the external half of the medial layer where the dissection usually occurs. Since these molecules play a role in resistance to compression, disorders not detected by our method may be involved in aortic dissection. Hyaluronan was seen adjacent to fibrin at the dissection tear, probably as an early wound repair phenomenon. Biglycan, hyaluronan and mostly versican are seen during advanced repairing. The mucoid deposits may represent various compounds which reflect different disorders in vascular biology.

Tissue diffusion and retention of metalloproteinases in ascending aortic aneurysms and dissections

“…In view of its histochemical characteristics, this mucoid material most likely corresponds to intact or modified large glycosaminoglycans. These either form part of PG molecules, in which they constitute lateral chains of a protein core, or exist in isolation, such as hyaluronan [18]. Several studies [11][12][13]17] have dealt with the role of metalloproteinases in nonatheromatous aortic diseases.…”

“…However, the relationship of MMPs to the areas of mucoid degeneration has never been explored. Although these areas, which are proteoglycan (PG)-rich, are common features in AscAA/AD [11], the exact nature [18] and the involvement of the molecules retained in these anionic regions are still unknown. Recently, we showed that thrombin, which has an affinity for sulfated glycosaminoglycans, could be retained within these areas [19].…”

Rotura espontânea de aneurisma da artéria cólica média

“…Slavin e col propuseram como causa a mediólise segmentar idiopática na qual se observa processo degenerativo da camada média (degeneração medial ou mediólise), caracterizado pela fragmentação do tecido elástico com formação de pequenos espaços preenchidos por tecido colágeno 2,12,13,14 . Esta alteração também é comumente encontrada nas dissecções agudas de aorta e nos aneurismas rotos da aorta abdominal 4 . Os aneurismas que acometem a artéria cólica média geralmente são assintomáticos, mas tornam-se graves em situação de rotura, trombose e embolização distal 2,8,9 .…”

Why Do Aortas Cleave or Dilate? Clues from an Electronic Scanning Microscopy Study in Human Ascending Aortas

“…Considering that the extracellular matrix (ECM) constitutes a great part of the arterial wall, and that it plays a pivotal role in the biomechanical properties of virtually every organ, it is probable that lesions of this compartment are involved in AscAA/AD. As mentioned above, alterations in mucoid content (probably proteoglycans) and in the elastic system have been described [6]. We previously showed by morphometry that in both diseases collagen is decreased [7] throughout the media in AscAA and mostly in the external portion of this layer (where the cleavage occurs) in AD.…”