Progress and controversies in unraveling the glomerular filtration mechanism.

PURPOSE OF REVIEW: At first sight, the glomerular filter appears like a problem that should be easily solved. The majority of researchers view the filter like an impermeable wall perforated by specialized and size-selective pores (pore model). However, the fact that this model is in conflict with many of the experimental findings suggests that it may not yet be complete.

RECENT FINDINGS: In the more recent electrokinetic model, we have proposed including electrical effects (streaming potentials). The present review investigates how this can provide a relatively simple mechanistic explanation for the great majority of the so far unexplained characteristics of the filter, for example why the filter never clogs.

SUMMARY: Understanding how the glomerular filter functions is a prerequisite to investigate the pathogenesis of proteinuric glomerular diseases and the link between glomerular proteinuria and cardiovascular disease.