Detoxification and endothelialization of glutaraldehyde-fixed bovine pericardium with titanium coating: a new technology for cardiovascular tissue engineering.
BACKGROUND
Endothelial cell seeding of glutardialdehyde-fixed biological heart valves is hypothesized to improve biocompatibility and durability; however, the toxicity of glutardialdehyde prevents its use as a biological coating. Therefore, different detoxification strategies are applied, including surface coating with titanium, before in vitro endothelialization of glutaraldehyde-fixed bovine pericardium as the base material for prosthetic heart valves.


RESULTS
Bovine pericardium was fixed with 0.25% glutardialdehyde. Detoxification was performed with citric acid, aldehyde dehydrogenase, and plasma deposition with titanium at low temperatures of 30 degrees C to 35 degrees C. Toxic glutaraldehyde ligands were quantified photometrically, and the vitality of seeded cells was tested to validate detoxification methods. Detoxification agents and titanium coating were applied before seeding with human endothelial cells. Endothelial cells were visualized by electron microscopic surface scanning. To evaluate cell adhesion, shear stress was applied by a flow of 5 L/min over 24 hours. Compared with untreated glutaraldehyde-fixed samples, treatment with the different agents reduced free aldehyde groups gradually (citric acid 5% < citric acid 10% < titanium < aldehyde dehydrogenase). A combination of citric acid 10%, aldehyde dehydrogenase, and titanium coating resulted in a reduction of free aldehyde ligands to 17.3+/-4.6% (P < or = 0.05) and demonstrated a vitality of seeded cells of 94+/-6.7% (P < or = 0.05). This procedure yielded a completely confluent layer of regular human endothelial cells (n=5). After application of shear stress for 24 hours on these endothelial layers, cell vitality was 81%.


CONCLUSIONS
Titanium coating combined with chemical procedures yielded significant detoxification and complete endothelialization of conventional glutaraldehyde-fixed pericardium. This new technique might improve glutardialdehyde-fixed cardiovascular bioimplants for better biocompatibility and longer durability.
Guldner
Norbert W
NW
Klinik für Herzchirurgie Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, D-233538 Lübeck, Germany. guldner@uni-luebeck.de.
Jasmund
Inka
I
Zimmermann
Hanngörg
H
Heinlein
Markus
M
Girndt
Britta
B
Meier
Veronika
V
Flüss
Florian
F
Rohde
Daniel
D
Gebert
Andreas
A
Sievers
Hans-Hinrich
HH
D000444:Aldehyde Dehydrogenase; D000818:Animals; D001705:Bioprosthesis; D002417:Cattle; D018929:Cell Culture Techniques; D002470:Cell Survival; D019343:Citric Acid; D020099:Coated Materials, Biocompatible; D042783:Endothelial Cells / Q000166:cytology*; D005404:Fixatives; D005976:Glutaral; D006350:Heart Valve Prosthesis; D006801:Humans; D010496:Pericardium / Q000166:cytology*; D010949:Plasma; D023822:Tissue Engineering / Q000379:methods*; D014025:Titanium
D020099:Coated Materials, Biocompatible; D005404:Fixatives; D019343:Citric Acid; D014025:Titanium; D000444:Aldehyde Dehydrogenase; D005976:Glutaral