Porcine bladder acellular matrix (ACM): protein expression, mechanical properties

Abstract

Experimentally, porcine bladder acellular matrix (ACM) that mimics extracellular matrix has excellent potential as a bladder substitute. Herein we investigated the spatial localization and expression of different key cellular and extracellular proteins in the ACM; furthermore, we evaluated the inherent mechanical properties of the resultant ACM prior to implantation. Using a proprietary decellularization method, the DNA contents in both ACM and normal bladder were measured; in addition we used immunohistochemistry and western blots to quantify and localize the different cellular and extracellular components, and finally the mechanical testing was performed using a uniaxial mechanical testing machine. The mean DNA content in the ACM was significantly lower in the ACM compared to the bladder. Furthermore, the immunohistochemical and western blot analyses showed that collagen I and IV were preserved in the ACM, but possibly denatured collagen III in the ACM. Furthermore, elastin, laminin and fibronectin were mildly reduced in the ACM. Although the ACM did not exhibit nucleated cells, residual cellular components (actin, myosin, vimentin and others) were still present. There was, on the other hand, no significant difference in the mean stiffness between the ACM and the bladder. Although our decellularization method is effective in removing nuclear material from the bladder while maintaining its inherent mechanical properties, further work is mandatory to determine whether these residual DNA and cellular remnants would lead to any immune reaction, or if the mechanical properties of the ACM are preserved upon implantation and cellularization.

One and four layer acellular bladder matrix for fascial tissue reconstruction

“…While collagen types I and IV are well preserved in the ABM, collagen type III remains within the biomaterial but is denatured [38]. Other ECM molecules including elastin, laminin and fibronectin are only slightly reduced in ABM.…”

Effects of Increasing Carbon Nanofiber Density in Polyurethane Composites for Inhibiting Bladder Cancer Cell Functions

“…First, design of the PU-CNF composites should be optimized to better emulate the elasticity of natural bladder tissue (0.06 to 0.25 N/m). Although composites containing more CNF than PU (i.e., 1:2 [PU:CNF] and 1:4) demonstrated better biological responses, the surface stiffness of these composites (0.26 to 0.29 N/m) 22 exceeded the range of natural bladder tissue. Second, it is imperative to evaluate the immunological response, such as understanding the extent of T-lymphocyte activation, to the PU-CNF composites.…”

“…To restore primary bladder function, urine storage, the bladder replacement material must possess a surface stiffness that emulates that of native bladder tissue, which ranges from 0.06 to 0.25 N/m. 22 The surface stiffness of composites containing more PU than CNF ranged between 0.13 and 0.18 N/m and approximated that of native bladder tissue. For composites containing equal parts or more of CNF than PU, the surface stiffness exceeded that of native bladder tissue, ranging from 0.26 to 0.29 N/m.…”

Recent advances in urologic tissue engineering

“…Scaffolds may be composed of either synthetic polymers or naturally occurring materials. Natural biomaterials are used in either the native form (amniotic membranes) [2], processed form (bladder acellular matrix) [3], or elemental form (collagen constructs) [4]. Commonly used synthetic biomaterials are PGA and poly(lactic-co-glycolic acid) (PLGA) [5].…”

“…Recent research has better characterized these biomaterials. Farhat et al [3] investigated the spatial localization and expression of extracellular proteins within porcine acellular bladder matrix. The authors identifi ed that important extracellular components, including type I and IV collagen, elastin, laminin, and fi bronectin, were present in the matrix.…”