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Placental growth factor contributes to micro-vascular abnormalization and blood-retinal barrier breakdown in diabetic retinopathy.

Kowalczuk L, Touchard E, Omri S, Jonet L, Klein C, Valamanes F, Berdugo M, Bigey P, Massin P, Jeanny JC, Behar-Cohen F - PLoS ONE (2011)

Bottom Line: For a better understanding of its role on the retina, we have evaluated the effect of a sustained PGF over-expression in rat ocular media, using ciliary muscle electrotransfer (ET) of a plasmid encoding rat PGF-1 (pVAX2-rPGF-1). pVAX2-rPGF-1 ET in the ciliary muscle (200 V/cm) was achieved in non diabetic and diabetic rat eyes.After the control of rPGF-1 expression, PGF-induced effects on retinal vasculature and on the blood-external barrier were evaluated respectively by lectin and occludin staining on flat-mounts.PGF and its receptor Flt-1 may therefore be looked upon as a potential regulatory target at this stage of the disease.

View Article: PubMed Central - PubMed

Affiliation: Institut National pour la Santé Et la Recherche Médicale U872, Physiopathology of ocular diseases: Therapeutic innovations, Paris, France.

ABSTRACT

Objective: There are controversies regarding the pro-angiogenic activity of placental growth factor (PGF) in diabetic retinopathy (DR). For a better understanding of its role on the retina, we have evaluated the effect of a sustained PGF over-expression in rat ocular media, using ciliary muscle electrotransfer (ET) of a plasmid encoding rat PGF-1 (pVAX2-rPGF-1).

Materials and methods: pVAX2-rPGF-1 ET in the ciliary muscle (200 V/cm) was achieved in non diabetic and diabetic rat eyes. Control eyes received saline or naked plasmid ET. Clinical follow up was carried out over three months using slit lamp examination and fluorescein angiography. After the control of rPGF-1 expression, PGF-induced effects on retinal vasculature and on the blood-external barrier were evaluated respectively by lectin and occludin staining on flat-mounts. Ocular structures were visualized through histological analysis.

Results: After fifteen days of rPGF-1 over-expression in normal eyes, tortuous and dilated capillaries were observed. At one month, microaneurysms and moderate vascular sprouts were detected in mid retinal periphery in vivo and on retinal flat-mounts. At later stages, retinal pigmented epithelial cells demonstrated morphological abnormalities and junction ruptures. In diabetic retinas, PGF expression rose between 2 and 5 months, and, one month after ET, rPGF-1 over-expression induced glial activation and proliferation.

Conclusion: This is the first demonstration that sustained intraocular PGF production induces vascular and retinal changes similar to those observed in the early stages of diabetic retinopathy. PGF and its receptor Flt-1 may therefore be looked upon as a potential regulatory target at this stage of the disease.

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Fluorescein angiograms of Brown-Norway rat eyes.(a) Observations with a classic angiograph (Pro III Fundus camera, Kowa), 4 and 6 weeks after pVAX2-rPGF ET. Angiograms were established with a scan angle of 30°. Vascular abnormalities were scored from 0 to 5 in accordance to the following grading: Grade 0, normal retinal vasculature, as observed in control fundus at week 6 (ONH, Optic Nerve Head); +1 point for each of the following changes - dilated (between white arrowheads) or tortuous (white arrows) vessels, microaneurysmal-like hyperfluorescent dots (black arrowheads) <10 or hyper-fluorescence around the ONH; +2 points for microaneurysmal-like hyper-fluorescent dots >10. (b) Observations with a confocal scanning Laser Ophthalmoscope (cSLO, Heidelberg Retina Angiograph I), 2, 3 and 5 weeks after pVAX2-rPGF ET. The same grading was used to score vascular abnormalities. The higher resolution of the cSLO allowed the observation of early fluorescein leakage (Grade 1), and the detection of strong vascular abnormalities at later stage (+ 1 point).
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pone-0017462-g002: Fluorescein angiograms of Brown-Norway rat eyes.(a) Observations with a classic angiograph (Pro III Fundus camera, Kowa), 4 and 6 weeks after pVAX2-rPGF ET. Angiograms were established with a scan angle of 30°. Vascular abnormalities were scored from 0 to 5 in accordance to the following grading: Grade 0, normal retinal vasculature, as observed in control fundus at week 6 (ONH, Optic Nerve Head); +1 point for each of the following changes - dilated (between white arrowheads) or tortuous (white arrows) vessels, microaneurysmal-like hyperfluorescent dots (black arrowheads) <10 or hyper-fluorescence around the ONH; +2 points for microaneurysmal-like hyper-fluorescent dots >10. (b) Observations with a confocal scanning Laser Ophthalmoscope (cSLO, Heidelberg Retina Angiograph I), 2, 3 and 5 weeks after pVAX2-rPGF ET. The same grading was used to score vascular abnormalities. The higher resolution of the cSLO allowed the observation of early fluorescein leakage (Grade 1), and the detection of strong vascular abnormalities at later stage (+ 1 point).

Mentions: Fluorescein angiography (FA) on pigmented eyes and the definition of a grading system (Fig. 2a) allowed a more precise analysis of the PGF-induced effects on retinal vasculature. Control rats showed normal vasculature throughout the follow-up period (Fig. 2a, Grade 0). Four weeks after ET, 40% of the PGF-treated eyes (n = 4/10) demonstrated dilated (mostly veins) and tortuous (mostly arterial) vessels, in central and peripheral retina (Fig. 2a, Grade 2). Six weeks after ET, 60% (n = 6/10) showed focal vessel leakage in the mid retinal periphery (Fig. 2a, Grade 3/4). Hyper fluorescent dots appeared as leaky micro-aneurysms. In three eyes, profuse dye leakage around the ONH increased with the angiographic sequence time, signing large vessel permeabilization (Fig. 2a, +1 point). No clear retinal neovascularization was observed at this time point.


Placental growth factor contributes to micro-vascular abnormalization and blood-retinal barrier breakdown in diabetic retinopathy.

Kowalczuk L, Touchard E, Omri S, Jonet L, Klein C, Valamanes F, Berdugo M, Bigey P, Massin P, Jeanny JC, Behar-Cohen F - PLoS ONE (2011)

Fluorescein angiograms of Brown-Norway rat eyes.(a) Observations with a classic angiograph (Pro III Fundus camera, Kowa), 4 and 6 weeks after pVAX2-rPGF ET. Angiograms were established with a scan angle of 30°. Vascular abnormalities were scored from 0 to 5 in accordance to the following grading: Grade 0, normal retinal vasculature, as observed in control fundus at week 6 (ONH, Optic Nerve Head); +1 point for each of the following changes - dilated (between white arrowheads) or tortuous (white arrows) vessels, microaneurysmal-like hyperfluorescent dots (black arrowheads) <10 or hyper-fluorescence around the ONH; +2 points for microaneurysmal-like hyper-fluorescent dots >10. (b) Observations with a confocal scanning Laser Ophthalmoscope (cSLO, Heidelberg Retina Angiograph I), 2, 3 and 5 weeks after pVAX2-rPGF ET. The same grading was used to score vascular abnormalities. The higher resolution of the cSLO allowed the observation of early fluorescein leakage (Grade 1), and the detection of strong vascular abnormalities at later stage (+ 1 point).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3049767&req=5

pone-0017462-g002: Fluorescein angiograms of Brown-Norway rat eyes.(a) Observations with a classic angiograph (Pro III Fundus camera, Kowa), 4 and 6 weeks after pVAX2-rPGF ET. Angiograms were established with a scan angle of 30°. Vascular abnormalities were scored from 0 to 5 in accordance to the following grading: Grade 0, normal retinal vasculature, as observed in control fundus at week 6 (ONH, Optic Nerve Head); +1 point for each of the following changes - dilated (between white arrowheads) or tortuous (white arrows) vessels, microaneurysmal-like hyperfluorescent dots (black arrowheads) <10 or hyper-fluorescence around the ONH; +2 points for microaneurysmal-like hyper-fluorescent dots >10. (b) Observations with a confocal scanning Laser Ophthalmoscope (cSLO, Heidelberg Retina Angiograph I), 2, 3 and 5 weeks after pVAX2-rPGF ET. The same grading was used to score vascular abnormalities. The higher resolution of the cSLO allowed the observation of early fluorescein leakage (Grade 1), and the detection of strong vascular abnormalities at later stage (+ 1 point).
Mentions: Fluorescein angiography (FA) on pigmented eyes and the definition of a grading system (Fig. 2a) allowed a more precise analysis of the PGF-induced effects on retinal vasculature. Control rats showed normal vasculature throughout the follow-up period (Fig. 2a, Grade 0). Four weeks after ET, 40% of the PGF-treated eyes (n = 4/10) demonstrated dilated (mostly veins) and tortuous (mostly arterial) vessels, in central and peripheral retina (Fig. 2a, Grade 2). Six weeks after ET, 60% (n = 6/10) showed focal vessel leakage in the mid retinal periphery (Fig. 2a, Grade 3/4). Hyper fluorescent dots appeared as leaky micro-aneurysms. In three eyes, profuse dye leakage around the ONH increased with the angiographic sequence time, signing large vessel permeabilization (Fig. 2a, +1 point). No clear retinal neovascularization was observed at this time point.

Bottom Line: For a better understanding of its role on the retina, we have evaluated the effect of a sustained PGF over-expression in rat ocular media, using ciliary muscle electrotransfer (ET) of a plasmid encoding rat PGF-1 (pVAX2-rPGF-1). pVAX2-rPGF-1 ET in the ciliary muscle (200 V/cm) was achieved in non diabetic and diabetic rat eyes.After the control of rPGF-1 expression, PGF-induced effects on retinal vasculature and on the blood-external barrier were evaluated respectively by lectin and occludin staining on flat-mounts.PGF and its receptor Flt-1 may therefore be looked upon as a potential regulatory target at this stage of the disease.

View Article: PubMed Central - PubMed

Affiliation: Institut National pour la Santé Et la Recherche Médicale U872, Physiopathology of ocular diseases: Therapeutic innovations, Paris, France.

ABSTRACT

Objective: There are controversies regarding the pro-angiogenic activity of placental growth factor (PGF) in diabetic retinopathy (DR). For a better understanding of its role on the retina, we have evaluated the effect of a sustained PGF over-expression in rat ocular media, using ciliary muscle electrotransfer (ET) of a plasmid encoding rat PGF-1 (pVAX2-rPGF-1).

Materials and methods: pVAX2-rPGF-1 ET in the ciliary muscle (200 V/cm) was achieved in non diabetic and diabetic rat eyes. Control eyes received saline or naked plasmid ET. Clinical follow up was carried out over three months using slit lamp examination and fluorescein angiography. After the control of rPGF-1 expression, PGF-induced effects on retinal vasculature and on the blood-external barrier were evaluated respectively by lectin and occludin staining on flat-mounts. Ocular structures were visualized through histological analysis.

Results: After fifteen days of rPGF-1 over-expression in normal eyes, tortuous and dilated capillaries were observed. At one month, microaneurysms and moderate vascular sprouts were detected in mid retinal periphery in vivo and on retinal flat-mounts. At later stages, retinal pigmented epithelial cells demonstrated morphological abnormalities and junction ruptures. In diabetic retinas, PGF expression rose between 2 and 5 months, and, one month after ET, rPGF-1 over-expression induced glial activation and proliferation.

Conclusion: This is the first demonstration that sustained intraocular PGF production induces vascular and retinal changes similar to those observed in the early stages of diabetic retinopathy. PGF and its receptor Flt-1 may therefore be looked upon as a potential regulatory target at this stage of the disease.

Show MeSH
Related in: MedlinePlus