title: The locally activated renin-angiotensin system is involved in albumin permeability in glomerular endothelial cells under high glucose conditions.
abstract: Although the diabetic milieu per se , hemodynamic changes, oxidative stress and local growth factors such as angiotensin II (AII) are considered to be mediators in the pathogenesis of diabetic nephropathy, the underlying pathways mediating the changes in glomerular endothelial cells (GECs) are not well understood. Therefore, we investigated changes in the renin-angiotensin system (RAS) components in high glucose (HG)-stimulated GECs and the role of the local RAS in morphological and functional changes in GECs under diabetic conditions.
  
  
  
  We stimulated GECs with 5.6 mM glucose or 30 mM glucose with or without an angiotensin II type I receptor blocker (ARB) in vitro and also performed experiments with Sprague-Dawley rats injected with diluent ( n = 16) or streptozotocin [ n = 16, diabetes (DM)]. Eight rats from each group were treated with ARB for 3 months in vivo . Real-time polymerase chain reaction, western blot analysis, enzyme-linked immunosorbent assay and immunofluorescent staining using cultured GECs were performed. The permeability of GECs to macromolecules was assessed by measuring the passage of fluorescein isothiocyanate-labeled bovine serum albumin. Morphological changes were also evaluated by scanning and transmission electron microscopy.
  
  
  
  There were significant increases in angiotensinogen expression in HG-stimulated GECs along with significant increases in AI and AII levels. Moreover, the expression of heparan sulfate glycosaminoglycans (HS-GAG) assessed by immunofluorescent staining was significantly lower and the permeability to albumin was significantly higher in GECs exposed to HG medium, and ARB treatment significantly abrogated these changes. Upon electron microscopy examination, the mean size of the GEC fenestrae was significantly greater in HG-stimulated GECs and DM rats, and these increases were significantly ameliorated by ARB.
  
  
  
  The local RAS within GECs was activated under HG conditions, and this activation may be associated with both an alteration in GEC fenestration and a decrease in HS-GAG, resulting in the development of albuminuria in diabetic nephropathy.
authors.affiliation: Department of Internal Medicine, College of Medicine, Severance Biomedical Science Institute, Brain Korea 21 PLUS, Yonsei University, Seoul, Korea.
authors.forename: Jisun
authors.initials: J
authors.lastname: Paeng
authors.affiliation: Department of Internal Medicine, College of Medicine, Severance Biomedical Science Institute, Brain Korea 21 PLUS, Yonsei University, Seoul, Korea.
authors.forename: Jimin
authors.initials: J
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, College of Medicine, Severance Biomedical Science Institute, Brain Korea 21 PLUS, Yonsei University, Seoul, Korea.
authors.forename: Jae Eun
authors.initials: JE
authors.lastname: Um
authors.affiliation: Department of Internal Medicine, College of Medicine, Severance Biomedical Science Institute, Brain Korea 21 PLUS, Yonsei University, Seoul, Korea.
authors.forename: Bo Young
authors.initials: BY
authors.lastname: Nam
authors.affiliation: Department of Internal Medicine, College of Medicine, Severance Biomedical Science Institute, Brain Korea 21 PLUS, Yonsei University, Seoul, Korea.
authors.forename: Hye-Young
authors.initials: HY
authors.lastname: Kang
authors.affiliation: Department of Internal Medicine, College of Medicine, Severance Biomedical Science Institute, Brain Korea 21 PLUS, Yonsei University, Seoul, Korea.
authors.forename: Seonghun
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, College of Medicine, Severance Biomedical Science Institute, Brain Korea 21 PLUS, Yonsei University, Seoul, Korea.
authors.forename: Hyung Jung
authors.initials: HJ
authors.lastname: Oh
authors.affiliation: Department of Internal Medicine, College of Medicine, Severance Biomedical Science Institute, Brain Korea 21 PLUS, Yonsei University, Seoul, Korea.
authors.forename: Jung Tak
authors.initials: JT
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, College of Medicine, Severance Biomedical Science Institute, Brain Korea 21 PLUS, Yonsei University, Seoul, Korea.
authors.forename: Seung Hyeok
authors.initials: SH
authors.lastname: Han
authors.affiliation: Department of Internal Medicine, School of Medicine, Ewha Womans University, Seoul, Korea.
authors.forename: Dong-Ryeol
authors.initials: DR
authors.lastname: Ryu
authors.affiliation: Department of Internal Medicine, College of Medicine, Severance Biomedical Science Institute, Brain Korea 21 PLUS, Yonsei University, Seoul, Korea.
authors.forename: Tae-Hyun
authors.initials: TH
authors.lastname: Yoo
authors.affiliation: Department of Internal Medicine, College of Medicine, Severance Biomedical Science Institute, Brain Korea 21 PLUS, Yonsei University, Seoul, Korea.
authors.forename: Shin-Wook
authors.initials: SW
authors.lastname: Kang
mesh_terms: D000418:Albumins / Q000378:metabolism*; D000804:Angiotensin II / Q000235:genetics / Q000378:metabolism; D000808:Angiotensinogen / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism / Q000473:pathology*; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology*; D006801:Humans; D007678:Kidney Glomerulus / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000187:drug effects*; D013549:Sweetening Agents / Q000494:pharmacology
chemical_list: D000418:Albumins; D044140:Receptor, Angiotensin, Type 1; D013549:Sweetening Agents; D000808:Angiotensinogen; D000804:Angiotensin II; D005947:Glucose
keywords: albuminuria; diabetic nephropathy; fenestrae; glomerular endothelial cells; renin-angiotensin system