Until today, more than 17% of the population in Mecklenburg Western-Pomerania suffer from chronic kidney disease (CKD) which was revealed by the SHIP study (Study of Health in Pomerania). 20% of CKD cases can be traced back to glomerulopathies. One common characteristic of glomerulopathies is the morphologic change of the glomerular filtration barrier which consists of endothelial cells, the glomerular basement membrane and podocytes. Under healthy conditions, the foot processes of the podocytes interdigitate with the foot processes of the neighboring podocytes with a filtration slit in between. Apart from the slit membrane protein nephrin, typical adherens junction proteins like occludin or JAM-A are also expressed at this cell-cell junction. This junction is therefore considered to be a specialized type of adherens junction, necessary to maintain the size-selectivity of the filtration barrier. During podocyte injury, podocyte foot processes lose their characteristic morphology and the typical meandering filtration slit becomes linearized, a process which is described as foot process effacement. Since morphological change is directly linked to change or loss of function, ultrastructural analysis of the foot processes is necessary for diagnostics and research. By using 3D-structured illumination microscopy (3D-SIM), we quantified these morphological changes as well as studied a possible biomarker, the tight junction protein claudin 5 (CLDN5). Our study showed a spatially ...