title: Sepsis induces albuminuria and alterations in the glomerular filtration barrier: a morphofunctional study in the rat.
abstract: BACKGROUND
  Increased vascular permeability represents one of the hallmarks of sepsis. In the kidney, vascular permeability is strictly regulated by the 'glomerular filtration barrier' (GFB), which is comprised of glomerular endothelium, podocytes, their interposed basement membranes and the associated glycocalyx. Although it is likely that the GFB and its glycocalyx are altered during sepsis, no study has specifically addressed this issue. The aim of this study was to evaluate whether albuminuria--the hallmark of GFB perm-selectivity--occurs in the initial stage of sepsis and whether it is associated with morphological and biochemical changes of the GFB.
  
  
  METHODS
  Cecal ligation and puncture (CLP) was used to induce sepsis in the rat. Tumor necrosis factor (TNF)-alpha levels in plasma and growth of microorganisms in the peritoneal fluid were evaluated at 0, 3 and 7 hours after CLP or sham-operation. At the same times, kidney specimens were collected and structural and ultrastructural alterations in the GFB were assessed. In addition, several components of GFB-associated glycocalyx, syndecan-1, hyluronan (HA) and sialic acids were evaluated by immunofluorescence, immunohistochemistry and lectin histochemistry techniques. Serum creatinine and creatinine clearance were measured to assess kidney function and albuminuria for changes in GFB permeability. Analysis of variance followed by Tukey's multiple comparison test was used.
  
  
  RESULTS
  Septic rats showed increased TNF-alpha levels and growth of microorganisms in the peritoneal fluid. Only a few renal corpuscles had major ultrastructural and structural alterations and no change in serum creatinine or creatinine clearance was observed. Contrarily, urinary albumin significantly increased after CLP and was associated with diffuse alteration in the glycocalyx of the GFB, which consisted in a decrease in syndecan-1 expression and in HA and sialic acids contents. Sialic acids were also changed in their structure, exhibiting a higher degree of acetylation.
  
  
  CONCLUSIONS
  In its initial phase, sepsis is associated with a significant alteration in the composition of the GFB-associated glycocalyx, with loss of GFB perm-selectivity as documented by albumin leakage into urine.
authors: Department of Medical and Surgical Critical Care, Section of Anesthesiology and Intensive Care, University of Florence, Azienda Ospedaliero-Universitaria Careggi, Largo Brambilla, 3, 50134 Florence, Italy. chiara.adembri@unifi.it
authors: Chiara
authors: C
authors: Adembri
authors: Eleonora
authors: E
authors: Sgambati
authors: Luca
authors: L
authors: Vitali
authors: Valentina
authors: V
authors: Selmi
authors: Martina
authors: M
authors: Margheri
authors: Alessia
authors: A
authors: Tani
authors: Laura
authors: L
authors: Bonaccini
authors: Daniele
authors: D
authors: Nosi
authors: Anna L
authors: AL
authors: Caldini
authors: Lucia
authors: L
authors: Formigli
authors: Angelo R
authors: AR
authors: De Gaudio
mesh_terms: D000419:Albuminuria / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D000818:Animals; D001202:Ascitic Fluid / Q000382:microbiology; D003404:Creatinine / Q000097:blood; D005455:Fluorescent Antibody Technique; D060730:Glomerular Filtration Barrier / Q000737:chemistry / Q000473:pathology* / Q000503:physiopathology / Q000648:ultrastructure; D008297:Male; D019158:N-Acetylneuraminic Acid / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D018805:Sepsis / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D053668:Syndecan-1 / Q000032:analysis; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: C508243:Sdc1 protein, rat; D053668:Syndecan-1; D014409:Tumor Necrosis Factor-alpha; D003404:Creatinine; D019158:N-Acetylneuraminic Acid