[The glomerular mesangium: a new perspective on its structure and function].

OBJECTIVES: The present study describes a new approach to the structure and function of the renal glomeruli, distinct from the traditional concept of structural support and in relationship with the alterations detected in this area in different diseases. METHODS: The structural and ultrastructural observations in the renal glomerulus reported elsewhere were compared with our own findings in different animal experiments. Furthermore, the biochemical and functional results from these studies are presented. RESULTS: Our observations in vivo corroborate the findings reported by other authors and support their hypotheses on the possible myofibroblastic nature of the glomerular mesangial cells and the relationship of the renal mesangium with the glomerular capillaries in areas with no glomerular basement membrane. CONCLUSIONS: The glomerular mesangium is shown to be a fundamental structure for glomerular hemodynamics by regulating the different properties of the mesangial cells and the role of the mesangial matrix in plasma ultrafiltration by processing its different components and preventing their deposition in this area.