Growth-related micromorphological characteristics of the porcine femoral artery.

BACKGROUND: In cardiovascular research small pigs breeds like Göttingen® minipigs (GM) are established animal models, but systematic data about the micromorphology of the GM vasculature at different ages are scarce. OBJECTIVE: The study was aimed at gaining knowledge about the micromorphology of the femoral artery (FA) from German Landrace pigs (DL) and GM during the period of growth over a body weight range of 10-40 kg. METHODS: FA samples from DL aged two or three months were compared to GM ones, aged 18 or 40 months using transmitted light microscopy. RESULTS: All FA samples showed typical characteristics of muscular arteries. Growth was associated with increased vessel wall thickness. In the GM this resulted in a slight decrease of the luminal diameter (LD), while in the DL pigs, an increase of the LD and smooth muscle cell content (10%) with decreased elastic fiber content (10%) has been detected. In contrast, within the 22 months lasting growth period of the GM, the tunica media content of smooth muscle cells and elastic fibers remained stable. CONCLUSIONS: FA maturation strongly depends on the pig breed and age. It can be different from what is described in humans.

Albumin solder covalently bound to a polymer membrane: New approach to improve binding strength in laser tissue soldering in-vitro.

Laser tissue soldering (LTS) based on indocyanine green (ICG)-mediated heat-denaturation of proteins might be a promising alternative technique for micro-suturing, but up to now the problem of too weak shear strength of the solder welds in comparison to sutures is not solved. Earlier reports gave promising results showing that solder supported by carrier materials can enhance the cohesive strength of the liquid solder. In these studies, the solder was applied to the carriers by dip coating. Higher reliability of the connection between the solder and the carrier material is expected when the solder is bound covalently to the carrier material. In the present study a poly(ether imide) (PEI) membrane served as carrier material and ICG-supplemented albumin as solder substrate. The latter was covalently coupled to the carrier membrane under physiological conditions to prevent structural protein changes. As laser source a diode continuous-wave laser emitting at 808 nm with intensities between 250 mW and 1500 mW was utilized. The albumin functionalized carrier membrane was placed onto the tunica media of explanted pig thoracic aortae forming an overlapping area of approximately 0.5×0.5 cm2. All tests were performed in a dry state to prevent laser light absorption by water. Infrared spectroscopy, spectro-photometrical determination of the secondary and primary amine groups after acid orange II staining, contact angle measurements, and atomic force microscopy proved the successful functionalization of the PEI membrane with albumin. A laser power of 450 mW LTS could generate a membrane-blood vessel connection which was characterized by a shear strength of 0.08±0.002 MPa, corresponding to 15% of the tensile strength of the native blood vessel. Theoretically, an overlapping zone of 4.1 mm around the entire circumference of the blood vessel could have provided shear strength of the PEI membrane-blood vessel compound identical to the tensile strength of the native blood vessel. These in-vitro results confirmed the beneficial effects of solder reinforcement by carrier membranes, and suggest LTS with covalently bound solders on PEI substrates for further studies in animal models.