title: Early systemic microvascular damage in pigs with atherogenic diabetes mellitus coincides with renal angiopoietin dysbalance.
abstract: BACKGROUND
  Diabetes mellitus (DM) is associated with a range of microvascular complications including diabetic nephropathy (DN). Microvascular abnormalities in the kidneys are common histopathologic findings in DN, which represent one manifestation of ongoing systemic microvascular damage. Recently, sidestream dark-field (SDF) imaging has emerged as a noninvasive tool that enables one to visualize the microcirculation. In this study, we investigated whether changes in the systemic microvasculature induced by DM and an atherogenic diet correlated spatiotemporally with renal damage.
  
  
  METHODS
  Atherosclerotic lesion development was triggered in streptozotocin-induced DM pigs (140 mg/kg body weight) by administering an atherogenic diet for approximately 11 months. Fifteen months following induction of DM, microvascular morphology was visualized in control pigs (n = 7), non-diabetic pigs fed an atherogenic diet (ATH, n = 5), and DM pigs fed an atherogenic diet (DM+ATH, n = 5) using SDF imaging of oral mucosal tissue. Subsequently, kidneys were harvested from anethesized pigs and the expression levels of well-established markers for microvascular integrity, such as Angiopoietin-1 (Angpt1) and Angiopoietin-2 (Angpt2) were determined immunohistochemically, while endothelial cell (EC) abundance was determined by immunostaining for von Willebrand factor (vWF).
  
  
  RESULTS
  Our study revealed an increase in the capillary tortuosity index in DM+ATH pigs (2.31±0.17) as compared to the control groups (Controls 0.89±0.08 and ATH 1.55±0.11; p<0.05). Kidney biopsies showed marked glomerular lesions consisting of mesangial expansion and podocyte lesions. Furthermore, we observed a disturbed Angpt2/Angpt1 balance in the cortex of the kidney, as evidenced by increased expression of Angpt2 in DM+ATH pigs as compared to Control pigs (p<0.05).
  
  
  CONCLUSIONS
  In the setting of DM, atherogenesis leads to the augmentation of mucosal capillary tortuosity, indicative of systemic microvascular damage. Concomitantly, a dysbalance in renal angiopoietins was correlated with the development of diabetic nephropathy. As such, our studies strongly suggest that defects in the systemic microvasculature mirror the accumulation of microvascular damage in the kidney.
authors.affiliation: Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Meriem
authors.initials: M
authors.lastname: Khairoun
authors.affiliation: Division of Experimental Cardiology, Department of Cardiology, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Mieke
authors.initials: M
authors.lastname: van den Heuvel
authors.affiliation: Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands; Einthoven Laboratory for Experimental Vascular Research, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Bernard M
authors.initials: BM
authors.lastname: van den Berg
authors.affiliation: Division of Experimental Cardiology, Department of Cardiology, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Oana
authors.initials: O
authors.lastname: Sorop
authors.affiliation: Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Rients
authors.initials: R
authors.lastname: de Boer
authors.affiliation: Division of Experimental Cardiology, Department of Cardiology, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Nienke S
authors.initials: NS
authors.lastname: van Ditzhuijzen
authors.affiliation: Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Ingeborg M
authors.initials: IM
authors.lastname: Bajema
authors.affiliation: Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Baelde
authors.affiliation: Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Malu
authors.initials: M
authors.lastname: Zandbergen
authors.affiliation: Division of Experimental Cardiology, Department of Cardiology, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Dirk J
authors.initials: DJ
authors.lastname: Duncker
authors.affiliation: Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands; Einthoven Laboratory for Experimental Vascular Research, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Ton J
authors.initials: TJ
authors.lastname: Rabelink
authors.affiliation: Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands; Einthoven Laboratory for Experimental Vascular Research, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Marlies E J
authors.initials: ME
authors.lastname: Reinders
authors.affiliation: Division of Experimental Cardiology, Department of Cardiology, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Wim J
authors.initials: WJ
authors.lastname: van der Giessen
authors.affiliation: Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands; Einthoven Laboratory for Experimental Vascular Research, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Joris I
authors.initials: JI
authors.lastname: Rotmans
mesh_terms: D042683:Angiopoietin-1 / Q000378:metabolism; D042702:Angiopoietin-2 / Q000378:metabolism; D042682:Angiopoietins / Q000378:metabolism*; D000818:Animals; D050197:Atherosclerosis / Q000378:metabolism / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental; D007668:Kidney / Q000378:metabolism* / Q000473:pathology*; D007678:Kidney Glomerulus / Q000378:metabolism / Q000473:pathology; D008297:Male; D055806:Microvessels; D013552:Swine; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D042683:Angiopoietin-1; D042702:Angiopoietin-2; D042682:Angiopoietins; D015415:Biomarkers; D042461:Vascular Endothelial Growth Factor A