ARTICLE Modification of Macroporous Titanium Tracheal Implants With Biodegradable Structures: Tracking In Vivo Integration for Determination of Optimal In Situ Epithelialization Conditions Nihal Engin Vrana, 1 Agnes Dupret-Bories, 1,2 Charlotte Bach, 1,3 Christophe Chaubaroux, 1 Christelle Coraux, 4 Dominique Vautier, 1,3 Fouzia Boulmedais, 5 Youssef Haikel, 1,3 Christian Debry, 1,2 Marie-Helene Metz-Boutigue, 1,3 Philippe Lavalle 1,3 1 Institut Q2 National de la Sante ´ et de la Recherche Me ´dicale, INSERM Unite ´ 977, 11 Rue Humann, 67085 Strasbourg, France; e-mail: philippe.lavalle@inserm.fr 2 Ho ˆ pitaux Universitaires de Strasbourg, Service Oto-Rhino-Laryngologie, 67098 Strasbourg, France 3 Faculte ´ de Chirurgie Dentaire, Universite ´ de Strasbourg, 1 Place de l’Ho ˆ pital, 67000 Strasbourg, France 4 Institut National de la Sante ´ et de la Recherche Me ´dicale, INSERM Unite ´ 903, 51092 Reims, France 5 Centre National de la Recherche Scientifique, UPR 22, Institut Charles Sadron, 23 rue du Loess, BP 84037, 67034 Strasbourg Cedex 2, France Received 19 October 2011; revision received 18 January 2012; accepted 26 January 2012 Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/bit.24456 ABSTRACT: Previously, we showed that macroporous tita- nium implants, colonized in vivo together with an epithelial graft, are viable options for tracheal replacement in sheep. To decrease the number of operating steps, biomaterial- based replacements for epithelial graft and intramuscular implantation were developed in the present study. Hybrid microporous PLLA/titanium tracheal implants were designed to decrease initial stenosis and provide a surface for epithelialization. They have been implanted in New Zealand white rabbits as tracheal substitutes and compared to intramuscular implantation samples. Moreover, a base- ment membrane like coating of the implant surface was also designed by Layer-by-Layer (LbL) method with collagen and alginate. The results showed that the commencement of stenosis can be prevented by the microporous PLLA. For determination of the optimum time point of epithelializa- tion after implantation, HPLC analysis of blood samples, C- reactive protein (CRP), and Chromogranin A (CGA) anal- yses and histology were carried out. Following 3 weeks the implant would be ready for epithelialization with respect to the amount of tissue integration. Calcein-AM labeled epi- thelial cell seeding shows that after 3 weeks implant surfaces were suitable for their attachment. CRP readings were steady after an initial rise in the first week. Cross-linked collagen/ alginate structures show nanofibrillarity and they form uniform films over the implant surfaces without damaging the microporosity of the PLLA body. Human respiratory epithelial cells proliferated and migrated on these surfaces which provided a better alternative to PLLA film surface. In conclusion, collagen/alginate LbL coated hybrid PLLA/tita- nium implants are viable options for tracheal replacement, together with in situ epithelialization. Biotechnol. Bioeng. 2012;9999: 1–13. ß 2012 Wiley Periodicals, Inc. KEYWORDS: titanium; trachea; implant; epithelialization; porosity; in vivo; CGA; collagen Introduction Respiratory system diseases are one of the most common causes of death, especially in high income countries. For example, tracheal restenosis might become a problem that can necessitate surgery. Moreover, tracheal damages due to cancer and congenital diseases are quite common and even though end-to-end anastomosis can solve the problem for short lengths (<5 cm) (Roomans, 2010), implants are necessary if the problem is recurrent or the damaged area is above the limits of end-to-end anastomosis. In recent years Correspondence to: P. Lavalle Contract grant sponsor: Re ´ gion Alsace Contract grant sponsor: PMNA (Po ˆle Mate ´ riaux et Nanosciences d’Alsace) Additional supporting information may be found in the online version of this article. ß 2012 Wiley Periodicals, Inc. Biotechnology and Bioengineering, Vol. 9999, No. 9999, 2012 1 BIT-11-964.R2(24456)