Piecemeal Mechanism Combining Sprouting and Intussusceptive Angiogenesis in Intravenous Papillary Formation Induced by PGE2 and Glycerol

Abstract

Recently, we demonstrated that in human intravascular papillary endothelial hyperplasia (IPEH), vein wall vascularization occurs in association with myriad papillae, a large part of which formed in the vascularized vein wall. Previously, using an animal model, we observed that PGE2 and glycerol administration around the femoral vein originates intense vascularization of the vein wall from its intimal endothelial cells (ECs). This vascularization is similar to that in IPEH. The aim of this study is to assess the mechanism of papillary formation, using this model after demonstrating papillary development in neo-vascularized femoral vein walls. In semithin and ultrathin sections, the sequential vascular and papillary development was as follows: (a) activation of vein intimal ECs, (b) sprouting of intimal ECs towards the vein media layer and microvessel development, (c) interconnection between neighboring microvessels originated elementary loops, which encircled vein wall components and formed papillae. The encircling ECs formed the papillary cover, and the encircled component formed the core. The papillae showed a similar structure to that of folds and pillars in intussusceptive angiogenesis, and (d) origin of secondary and complex loop systems by interconnection of neighboring elementary loops and by splitting of papillae by new loops, with abundant papillary development. In conclusion, the results support a piecemeal angiogenic mechanism in papillary formation, with association of sprouting and intussusceptive types of angiogenesis. Further studies are needed to assess whether the intravascular papillae described in several pathologic processes, including vessel tumors, such as Dabska's tumor, retiform hemangioendothelioma, and angiosarcoma, follow a similar mechanism. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1781-1792, 2017. © 2017 Wiley Periodicals, Inc.

Segmentation of Dilated Hemorrhoidal Veins in Hemorrhoidal Disease

“…In this and previous works [Díaz-Flores et al, 2017a, b], we demonstrate the similarity between both types of structures. A similar phenomenon has also been described after perivenous administration of PGE2 and glycerol [Díaz-Flores et al, 2017b]. Likewise, in certain vascular reactive processes, as occurs in intravascular papillary endothelial hyperplasia [Díaz-Flores et al, 2016], densely grouped thrombotic FPPs occur without septa formation (ineffective segmen- Fig.…”

“…In these experimental conditions and following sequential evolution, the first finding was sprouting angiogenesis, with the growth and migration of vein intimal ECs toward the media layer, followed by the formation of numerous intraparietal vascular channels [Díaz-Flores et al, 1994, 2017b. The source of the newly formed channels in the vein walls is generally attributed to the vasa vasorum.…”

“…Neovascularization with the formation of vascular channels in the vein wall or thrombi has been pointed out in hemorrhoidal disease [Chung et al, 2004;Li et al, 2015], in chronic venous disease [Ritman and Lerman, 2007;Kachlík et al, 2008;Tonar et al, 2012;Nees et al, 2013], and in experimental conditions, including the development of similar vascularization in the wall of the rat femoral vein after perivenous application of PGE2 and glycerol [Díaz-Flores et al, 1994, 2017b. In these experimental conditions and following sequential evolution, the first finding was sprouting angiogenesis, with the growth and migration of vein intimal ECs toward the media layer, followed by the formation of numerous intraparietal vascular channels [Díaz-Flores et al, 1994, 2017b.…”

Hemorrhage of MRI and Immunohistochemical Panels Distinguish Secretory Carcinoma From Acinic Cell Carcinoma

“…The product of this fusion gene induces angiogenesis through VEGF, and VEGF overexpression is known to induce tumor‐related cyst formation, peritumoral edema formation and hemorrhage . Furthermore, the papillary stromal components in SC were abundant in vessels, and the papillary formation is associated with angiogenesis in some tumors . Our preliminary examination shows more abundant neovascularization in SC than in ACC, and the angiogenetic process may be crucial in SC.…”

“…23 Furthermore, the papillary stromal components in SC were abundant in vessels, and the papillary formation is associated with angiogenesis in some tumors. 24 Our preliminary examination shows more abundant neovascularization in SC than in ACC, and the angiogenetic process may be crucial in SC. Another important clue for distinguishing SC from ACC is an immunohistochemical analysis.…”