Glycocalix changes in morpho-functional alterations of the glomerular filtration barrier during sepsis

Syndecan-1 and sialic acids are glycocalix components that contribute to maintain the structure and functions of the glomerular filtration barrier (GFB). The aim of this investiga- tion was to evaluate expression changes of syndecan-1 and sial- ic acids in GFB, in early stages of an experimental animal model of polymicrobial sepsis. Experiments were performed on adult male rats assigned to two groups: 1) sham-operated (n=15); 2) Caecal Ligation and Puncture (CLP) (n=19). In order to evaluate sepsis, TNF-a levels in plasma and growth of microorganisms in the peritoneal fluid were relieved at 0 h, 3 h and 7 h after CLP or sham-operation. Kidney specimens were collected and structural and ultrastructural alterations in the GFB were assessed. Syndecan-1 expression was investigated by using immunofluorescence; sialic acids expression was evaluat- ed by using lectin histochemistry (MAA, SNA, PNA and SBA), in association with enzymatic and chemical treatments. Protein urine level was measured to assess changes in GFB permeability. The results showed in septic rats: 1) a rise in TNF- a and growth of microorganisms in the peritoneal fluid; 2) massive proteinuria; 3) structural and ultrastructural changes of GFB; 4) significant decrease of syndecan-1 and decrease and change in chemical structure of sialic acids, in particular an increase of acetylation. These findings indicate that in sep- sis, from its earliest development, alteration of GFB structure and ultrastructure, as such as of glycocalyx, occurs. This dam- age is associated to loss of GBF permeselectivity.