615 Original Paper Cell Physiol Biochem 2010;25:615-622 Accepted: March 04, 2010 Cellular Physiology Cellular Physiology Cellular Physiology Cellular Physiology Cellular Physiology and Biochemistr and Biochemistr and Biochemistr and Biochemistr and Biochemistry Copyright © 2010 S. Karger AG, Basel Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com © 2010 S. Karger AG, Basel 1015-8987/10/0256-0615$26.00/0 Accessible online at: www.karger.com/cpb Growth of Vascular Smooth Muscle Cells on Collagen I Exposed to RBL-2H3 Mastocytoma Cells Hana Maxová 1,5 , Lucie Bacáková 4,5 , Adam Eckhardt 4,5 , Ivan Mikšík 4,5 , Vera Lisá 4 , Jana Novotná 2,5 and Jan Herget 3,5 1 Department of Pathological Physiology, 2 Department of Medical Chemistry and Biochemistry, 3 Department of Physiology, 2 nd Medical School, Charles University, 4 Institute of Physiology, Academy of Sciences of the Czech Republic and 5 Centre for Cardiovascular Research, Prague Key Words Pulmonary hypertension • Vascular remodeling • Mast cells • Proteases • Collagen degradation • Smooth muscle cell proliferation • High performance liquid chromatography • Mass spectrometry Abstract Remodeling of the peripheral pulmonary vasculature during chronic hypoxia is characterized by acceler- ated collagenolysis and thickening of the vascular wall. Low molecular weight peptides, products of cleav- age by interstitial collagenase and muscular layer in the peripheral pulmonary vessels, are typically present. The aim of this “in vitro” study was to verify that mast cells (RBL-2H3) as a potent source of a variety of biomolecules which can affect vessel wall remodeling are capable of splitting collagen and then facilitating the growth of vascular smooth muscle cells (VSMC). Collagen I was exposed to RBL-2H3 cells cultured 48 hours under normoxic or hypoxic (3% O 2 ) conditions and then seeded with VSMC. The VSMC proliferated with the shortest doubling time and reached the highest cell population density on the collagen pre-modified with hypoxic RBL-2H3 cells. This increased growth activity of VSMC was probably due to the fragmentation of collagen by proteases released from RBL-2H3 cells. Absolute amount of col- lagen fragments was similar in samples exposed to normoxic and hypoxic RBL-2H3 cells, but the con- centration of at least one collagen fragment was sig- nificantly higher under hypoxic conditions. Mast cells exposed to hypoxia are more capable to split colla- gen and facilitate the growth of VSMC. Introduction Both pulmonary and systemic hypertension are serious diseases associated with remodeling of the vascular wall structure, which involves proliferation of vascular smooth muscle cells (VSMC) and their migration from the tunica intima to the media. This can result in thickening of the vessel wall, stenosis of the vascular lumen, increased vascular resistance and subsequent heart failure [1, 2]. A prerequisite for activation of the migratory and proliferative response of VSMC is degradation of Hana Maxová Department of Pathological Physiology 2 nd Medical School, Charles University Plzenská 221, 150 00 Prague 5 (Czech Republic) Tel. and Fax +420 257210995, E-Mail hana.maxova@lfmotol.cuni.cz