Journal Article

Acellularization-Induced Changes in Tensile Properties Are Organ Specific - An In-Vitro Mechanical and Structural Analysis of Porcine Soft Tissues

Keil, Isabel, Prietzel, Torsten, Koch, Holger, Aust, Gabriela, Scheidt, Holger A., Fritsch, Sebastian, Möbius, Robert, Hammer, Niels, Wagner, Martin F. X., Boldt, Andreas, Schleifenbaum, Stefan

2016

Overview

Though xenogeneic acellular scaffolds are frequently used for surgical reconstruction, knowledge of their mechanical properties is lacking. This study compared the mechanical, histological and ultrastructural properties of various native and acellular specimens. Porcine esophagi, ureters and skin were tested mechanically in a native or acellular condition, focusing on the elastic modulus, ultimate tensile stress and maximum strain. The testing protocol for soft tissues was standardized, including the adaption of the tissue's water content and partial plastination to minimize material slippage as well as templates for normed sample dimensions and precise cross-section measurements. The native and acellular tissues were compared at the microscopic and ultrastructural level with a focus on type I collagens. Increased elastic modulus and ultimate tensile stress values were quantified in acellular esophagi and ureters compared to the native condition. In contrast, these values were strongly decreased in the skin after acellularization. Acellularization-related decreases in maximum strain were found in all tissues. Type I collagens were well-preserved in these samples; however, clotting and a loss of cross-linking type I collagens was observed ultrastructurally. Elastins and fibronectins were preserved in the esophagi and ureters. A loss of the epidermal layer and decreased fibronectin content was present in the skin. Acellularization induces changes in the tensile properties of soft tissues. Some of these changes appear to be organ specific. Loss of cross-linking type I collagen may indicate increased mechanical strength due to decreasing transverse forces acting upon the scaffolds, whereas fibronectin loss may be related to decreased load-bearing capacity. Potentially, the alterations in tissue mechanics are linked to organ function and to the interplay of cells and the extracellular matrix, which is different in hollow organs when compared to skin.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Animals / Bearing capacity / Biology and Life Sciences / Biomechanics / Biomedical materials / Clotting / Collagen / Collagen (type I) / Collagen Type I - metabolism / Cross-linking / Crosslinking / Elastic Modulus - physiology / Esophagus / Extracellular matrix / Extracellular Matrix - metabolism / Fibronectin / Fibronectins / Health aspects / Materials science / Mechanical properties / Medicine and Health Sciences / Modulus of elasticity / Moisture content / Organs / Physical Sciences / Physiological aspects / Plastic surgery / Reconstructive surgery / Research and Analysis Methods / Scaffolds / Skin / Skin & tissue grafts / Skin tests / Slippage / Soft tissues / Strain / Structural analysis / Studies / Surgery / Swine / Tendons / Tensile properties / Tensile Strength - physiology / Tensile stress / Tissue engineering / Tissues / Transplants & implants / Trauma / Water content