Since Arg-II is also found in the synaptopodin-negative cells in the glomeruli, future studies shall systematically investigate whether there is an age-associated increase in Arg-II in the mesangial cells and/or endothelial cells and whether the cell-specific Arg-II participates in the development of glomerulopathy and/or proteinuria associated with aging. This evidence concerns the gene SYNPO and lipoprotein glomerulopathy.