Ultrastructural basement membrane topography of the bladder epithelium

The basement membrane underlies epithelium and separates it from deeper tissues. Recent studies suggest that nanoscale topography of the surface of basement membrane may modulate adhesion, migration, proliferation and differentiation of overlying epithelium. This study was performed to elucidate nanoscale topographic features of basement membrane of the bladder. Bladder tissues were obtained from three adult female rhesus macaques. A process was developed to remove the epithelium while preserving the underlying basement membrane, and tissues were evaluated by immunohistochemistry and scanning electron microscopy (SEM). Detailed measurements were made of stereo SEM images to quantitatively define topographic features. Measurements made from multiple SEM images of bladder basement membrane provided the following values for topographic features: mean feature height, 178±57 nm; mean fiber diameters, 52±28 nm; mean pore diameter, 82±49 nm; and mean interpore distance (center to center), 127±54 nm. These dimensions are similar to those reported previously for basement membranes of other species and anatomical locations. This information provides a rational basis for design of nanostructured biomaterials to produce composite grafts for repair or replacement of segments of the urinary tract.