Imaging glomeruli in renal biopsy specimens.

Glomerular capillary loops are complex vascular filters composed of interdigitating podocytes and fenestrated endothelial cells with an intervening proteoglycan-rich extracellular matrix. This arrangement is crucial to maintaining the filtration barrier but renders the glomerulus difficult to analyze by conventional two-dimensional histochemical techniques. When pathologic lesions distort glomerular architecture, its complex morphology is even more challenging to interpret. Fortunately, recent advances in microscopes and computer software now enable glomerular enthusiasts to dissect this complex structure with finer detail. In this review we explore the application of new methodologies such as two-photon microscopy that optimize three-dimensional, multicolor imaging and single-cell segmentation of glomerular components.