HISTOLOGY AND HISTOPATHOLOGY

Cellular and Molecular Biology

 

Medial artery calcification of uremic patients: a histological, histochemical and ultrastructural study

P. Ballanti1, G. Silvestrini1, S. Pisanò1,2, P. De Paolis3, S. Di Giulio3, D. Mantella3, M. Iappelli3, A. Favarò3, E. Bonucci1 and G. Coen2

1Department of Experimental Medicine, Sapienza University, Rome, Italy, 2Ospedale Israelitico, Rome, Italy and 3S. Camillo Hospital, Rome, Italy.

Offprint requests to: Giorgio Coen, MD, Ospedale Israelitico, Via Dandolo 75, 00153 Rome, Italy. e-mail address: giorgio.coen@gmail.com


Summary. Recent findings suggest that vascular calcification (VC) is an active process similar to bone mineralization, the vascular smooth muscle cells (VSMCs) undergoing phenotypic differentiation into osteoblastic cells and synthesizing calcification-regulating proteins found in bone. This study has investigated the VC process of uremic patients, with a morphologic approach. Epigastric artery samples from 49 uremic, non-diabetic patients were taken during kidney transplantation. Sections from paraffin-embedded samples were stained with hematoxylin/eosin and von Kossa. CD68 was immunohistochemically detected, and sections from frozen samples were stained with Oil Red O. Deeply calcified samples were stained with Picrosirius Red, PAS, and Alcian blue. Specimens from one patient with moderate and one with severe VC were examined under the electron microscope. None of the samples had atherosclerosis. Calcifications were found in the media of 38 patients. In 23, dot-like calcifications were irregularly scattered near the adventitia (light VC); in 11, granular calcifications formed concentric rings near the adventitia (moderate-advanced VC); in 4, zones of consolidated calcifications were found (severe VC). These zones were poor in collagen, glycoproteins and proteoglycans. In cases with moderate or severe VC, VSCMs showed necrotic changes. Matrix vesicles could be recognized in the extracellular spaces. In cases with severe VC, uncalcified or partially calcified membranous bodies were found, together with Liesegang rings. Patches of fibrin were also found. These findings point to a mainly degenerative mechanism of VC, which proceeds from the outer portion of the media. An active mechanism, however, cannot be excluded. A unifying hypothesis is suggested
. Histol Histopathol 26, 191-200 (2011)

Key words: Artery calcification, Dialysis patients, Cell necrosis, Matrix vesicles, Liesegang rings

DOI: 10.14670/HH-26.191