Molecular analysis of blood-retinal barrier loss in the Akimba mouse, a model of advanced diabetic retinopathy.
The molecular mechanisms of vascular leakage in diabetic macular edema and proliferative retinopathy are poorly understood, mainly due to the lack of reliable in vivo models. The Akimba (Ins2(Akita)VEGF(+/-)) mouse model combines retinal neovascularization with hyperglycemia, and in contrast to other models, displays the majority of signs of advanced clinical diabetic retinopathy (DR). To study the molecular mechanism that underlies the breakdown of the blood-retinal barrier (BRB) in diabetic macular edema and proliferative diabetic retinopathy, we investigated the retinal vasculature of Akimba and its parental mice Kimba (trVEGF029) and Akita (Ins2(Akita)). Quantitative PCR, immunohistochemistry and fluorescein angiography were used to characterize the retinal vasculature with special reference to the inner BRB. Correlations between the degree of fluorescein leakage and retinal gene expression were tested by calculating the Spearman's correlation coefficient. Fluorescein leakage demonstrating BRB loss was observed in Kimba and Akimba, but not in Akita or wild type mice. In Kimba and Akimba mice fluorescein leakage was associated with focal angiogenesis and correlated significantly with Plvap gene expression. PLVAP is an endothelial cell-specific protein that is absent in intact blood-retinal barrier, but its expression significantly increases in pathological conditions such as DR. Furthermore, in Akimba mice BRB disruption was linked to decreased expression of endothelial junction proteins, pericyte dropout and vessel loss. Despite fluorescein leakage, no alteration in BRB protein levels or pericyte coverage was detected in retinas of Kimba mice. In summary, our data not only demonstrate that hyperglycemia sensitizes retinal vasculature to the effects of VEGF, leading to more severe microvascular changes, but also confirm an important role of PLVAP in the regulation of BRB permeability.
Ocular Angiogenesis Group, Departments of Ophthalmology and Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. Electronic address: j.wisniewska@amc.uva.nl.
Joanna
J
Wisniewska-Kruk
Ocular Angiogenesis Group, Departments of Ophthalmology and Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. Electronic address: i.klaassen@amc.uva.nl.
Ingeborg
I
Klaassen
Ocular Angiogenesis Group, Departments of Ophthalmology and Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. Electronic address: i.m.vogels@amc.uva.nl.
Ilse M C
IM
Vogels
Department of Molecular Ophthalmology, Lions Eye Institute, Nedlands, Western Australia, Australia. Electronic address: AaronMagno@lei.org.au.
Aaron L
AL
Magno
Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia. Electronic address: may.lai@uwa.edu.au.
Chooi-May
CM
Lai
Ocular Angiogenesis Group, Departments of Ophthalmology and Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. Electronic address: c.j.vannoorden@amc.uva.nl.
Cornelis J F
CJ
Van Noorden
Ocular Angiogenesis Group, Departments of Ophthalmology and Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Clinical and Molecular Ophthalmogenetics, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Science (KNAW), Amsterdam, The Netherlands. Electronic address: r.schlingemann@amc.uva.nl.
Reinier O
RO
Schlingemann
Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia. Electronic address: elizabeth.rakoczy@uwa.edu.au.
Elizabeth P
EP
Rakoczy
D042501:Angiogenic Proteins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D018952:Antigens, CD34 / Q000235:genetics / Q000378:metabolism; D001813:Blood-Retinal Barrier / Q000473:pathology*; D002199:Capillary Permeability; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D018925:Chemokines / Q000235:genetics / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D000071063:Endoglin; D005451:Fluorescein Angiography; D015870:Gene Expression; D006943:Hyperglycemia / Q000235:genetics / Q000473:pathology; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008269:Macular Edema / Q000235:genetics / Q000473:pathology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008817:Mice, Mutant Strains; D020286:Pericytes / Q000473:pathology; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015861:Retinal Neovascularization / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D012171:Retinal Vessels / Q000378:metabolism / Q000473:pathology*; D014841:von Willebrand Factor / Q000235:genetics / Q000378:metabolism
D042501:Angiogenic Proteins; D018952:Antigens, CD34; D002352:Carrier Proteins; D018925:Chemokines; D000071063:Endoglin; C502004:Eng protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; C486772:Plvap protein, mouse; D014841:von Willebrand Factor
Akimba; BRB; PLVAP; blood-retinal barrier; diabetic macular edema; diabetic retinopathy; mouse models; retina