Biomolecular Engineering 21 (2004) 73–80 Polystyrene surface coated with vitamin E modulates human granulocyte adhesion and MMP-9 release F. Renò, F. Lombardi, M. Cannas ∗ Human Anatomy Laboratory, Research Center for Biocompatibility, Department of Medical Sciences, University of Eastern Piedmont “A.Avogadro”, Via Solaroli 17, 28100 Novara, Italy Received 16 June 2003; received in revised form 3 November 2003; accepted 19 November 2003 Abstract Vitamin E (Vit.E, -tocopherol) is a natural biological antioxidant and antinflammatory agent, which protects cells from the effects of free radicals and inhibits inflammation. For such properties Vit.E has been used to improve the biocompatibility of materials such as cellulose membrane for hemodialysis. In this study granulocytes adhesion and activation have been studied after contact with normal cell culture grade polystyrene (PS) and Vit.E-coated polystyrene (Vit.E 0.1 and 0.3% (v/v)) using optical microscopy, flow cytometry and substrate zymography. Vit.E increased the number of adherent granulocytes both at 0.1% (11470 ± 1064 cells/cm 2 , P< 0.01) and 0.3% (13706 ± 818 cells/cm 2 , P< 0.001) concentration compared to normal PS (5529 ± 692 cells/cm 2 ). The morphology of granulocytes adherent to Vit.E–PS appeared lightly altered and no differences have been observed in their respiratory burst compared to control granulocyte, while matrix metalloproteinase 9 or gelatinase B (MMP-9) release and activation were increased compared to the normal PS samples. Our data indicate that Vit.E-coated surface induced an increase in granulocytes adhesion and MMP-9 release in the absence of the typical oxidative stress, hallmark of granulocytes activation. A possible explanation of the phenomenon is that Vit.E modifies the surface protein adsorption thus increasing cell adhesion and in turn MMP-9 releasing. © 2004 Elsevier B.V. All rights reserved. Keywords: Vitamin E; Granulocytes; Adhesion; MMP-9; Biocompatibility 1. Introduction Materials implantation in the human body causes a tissue trauma due both to the surgery procedure and the presence of a new contact surface in the biological environment. The interactions of circulating and tissue cells with the mate- rial surface evoke both a specific leukocytes inflammatory response and a wound healing reaction [1]. In fact, after the prosthesis implantation, neutrophil granulocytes adhere along with other leukocytes to polymeric artificial surfaces [2] by the adsorbed plasma protein layer [3,4]. Following adhesion to biomaterial surfaces, granulocytic phagocytosis, respiratory burst and protease (gelatinase B or MMP-9 and elastase) release may occur, resulting in a dam- age in the surrounding tissue. Furthermore, many aspects of acute and chronic inflammatory processes are mediated by oxidants released by activated granulocytes and monocytes, ∗ Corresponding author. Tel.: +39-0321-660632; fax: +39-0321-660632. E-mail address: cannas@med.unipmn.it (M. Cannas). thank to their ability to induce cellular production of cy- tokines [5]. As granulocytes activation is an early event in the inflammation process it has been taken as an indicator for risk assessment of biopolymer-mediated inflammation [6]. Vitamin E (Vit.E, -tocopherol) is a natural biological antioxidant, that prevents peroxides accumulation and pro- tects cells from free radicals effects [7]. Vit.E has been also described as an antinflammatory agent able to inhibit many key events in inflammation such as IL-1 release from activated monocytes [8], monocyte adhesion to en- dothelial cells [9] and respiratory burst [10]. The Vit.E anti-oxidative and anti-inflammatory properties have been extensively utilized to improve the biostability and the bio- compatibility of different biomaterials. In fact Vit.E has been used in the production of amphiphilic monomers [11] and it has been added to different biocompatible materials such as poly(etherurethane urea) elastomers [12], acrylic bone cements [13], and recently to ultrahigh molecular weight polyethylene [14]. Another important application of Vit.E is the production of Vit.E-modified dialysis cellulose 1389-0344/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.bioeng.2003.11.001