Limits...
VEGF164-mediated inflammation is required for pathological, but not physiological, ischemia-induced retinal neovascularization.

Ishida S, Usui T, Yamashiro K, Kaji Y, Amano S, Ogura Y, Hida T, Oguchi Y, Ambati J, Miller JW, Gragoudas ES, Ng YS, D'Amore PA, Shima DT, Adamis AP - J. Exp. Med. (2003)

Bottom Line: These data highlight important molecular and cellular differences between physiological and pathological retinal neovascularization.These processes provide positive and negative angiogenic regulation, respectively.Together, new therapeutic approaches for selectively targeting pathological, but not physiological, retinal neovascularization are outlined.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Boston 02114, USA.

ABSTRACT
Hypoxia-induced VEGF governs both physiological retinal vascular development and pathological retinal neovascularization. In the current paper, the mechanisms of physiological and pathological neovascularization are compared and contrasted. During pathological neovascularization, both the absolute and relative expression levels for VEGF164 increased to a greater degree than during physiological neovascularization. Furthermore, extensive leukocyte adhesion was observed at the leading edge of pathological, but not physiological, neovascularization. When a VEGF164-specific neutralizing aptamer was administered, it potently suppressed the leukocyte adhesion and pathological neovascularization, whereas it had little or no effect on physiological neovascularization. In parallel experiments, genetically altered VEGF164-deficient (VEGF120/188) mice exhibited no difference in physiological neovascularization when compared with wild-type (VEGF+/+) controls. In contrast, administration of a VEGFR-1/Fc fusion protein, which blocks all VEGF isoforms, led to significant suppression of both pathological and physiological neovascularization. In addition, the targeted inactivation of monocyte lineage cells with clodronate-liposomes led to the suppression of pathological neovascularization. Conversely, the blockade of T lymphocyte-mediated immune responses with an anti-CD2 antibody exacerbated pathological neovascularization. These data highlight important molecular and cellular differences between physiological and pathological retinal neovascularization. During pathological neovascularization, VEGF164 selectively induces inflammation and cellular immunity. These processes provide positive and negative angiogenic regulation, respectively. Together, new therapeutic approaches for selectively targeting pathological, but not physiological, retinal neovascularization are outlined.

Show MeSH

Related in: MedlinePlus

Role of monocytes in pathological retinal neovascularization. (A) Pathological neovascularization (arrows, D7) treated with PBS control-liposomes (n = 8) was not inhibited. (B) Pathological neovascularization (arrows, D7) treated with clodronate-liposomes (n = 8). Notably, the pathological neovascular budding (C, PaNV) was suppressed (P < 0.01), whereas revascularization (D, phRV) was not (P > 0.05). (E–J) Monocyte adhesion was observed just before and during pathological neovascularization (H–J). Green fluorescence from the anti-CD13 antibody (E and H) and red fluorescence from the rhodamine-coupled Con A (F and I) identifies the Con A–stained cells as being CD13-positive leukocytes (arrows) when the images were superimposed (G and J). (K) Monocyte VEGF mRNA expression in normoxia (21% oxygen) and hypoxia (1% oxygen). VEGF levels were markedly increased in response to hypoxic stimulation. Bars: (E–J) 50 μm; (A and B) 0.5 mm.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2194095&req=5

fig4: Role of monocytes in pathological retinal neovascularization. (A) Pathological neovascularization (arrows, D7) treated with PBS control-liposomes (n = 8) was not inhibited. (B) Pathological neovascularization (arrows, D7) treated with clodronate-liposomes (n = 8). Notably, the pathological neovascular budding (C, PaNV) was suppressed (P < 0.01), whereas revascularization (D, phRV) was not (P > 0.05). (E–J) Monocyte adhesion was observed just before and during pathological neovascularization (H–J). Green fluorescence from the anti-CD13 antibody (E and H) and red fluorescence from the rhodamine-coupled Con A (F and I) identifies the Con A–stained cells as being CD13-positive leukocytes (arrows) when the images were superimposed (G and J). (K) Monocyte VEGF mRNA expression in normoxia (21% oxygen) and hypoxia (1% oxygen). VEGF levels were markedly increased in response to hypoxic stimulation. Bars: (E–J) 50 μm; (A and B) 0.5 mm.

Mentions: To investigate the role of monocytes in pathological neovascularization, clodronate-liposomes were used to inactivate monocyte lineage cells. Compared with PBS-liposomes (Fig. 4 A), monocyte-selective depletion (Fig. 4 B) led to a significant suppression of pathological neovascularization (Fig. 4 C), but had negligible effect on revascularization (Fig. 4 D). Immunohistochemistry confirmed that a subset of the adherent leukocytes in the vasculature (Fig. 4, E–J) were positive for CD13, aminopeptidase N coexpressed with MHC-II for monocyte-surface antigen processing. RT-PCR showed that circulating monocytes isolated from rats with proliferative retinopathy expressed VEGF120 and VEGF164, which was markedly induced after hypoxic stimulation (Fig. 4 K).


VEGF164-mediated inflammation is required for pathological, but not physiological, ischemia-induced retinal neovascularization.

Ishida S, Usui T, Yamashiro K, Kaji Y, Amano S, Ogura Y, Hida T, Oguchi Y, Ambati J, Miller JW, Gragoudas ES, Ng YS, D'Amore PA, Shima DT, Adamis AP - J. Exp. Med. (2003)

Role of monocytes in pathological retinal neovascularization. (A) Pathological neovascularization (arrows, D7) treated with PBS control-liposomes (n = 8) was not inhibited. (B) Pathological neovascularization (arrows, D7) treated with clodronate-liposomes (n = 8). Notably, the pathological neovascular budding (C, PaNV) was suppressed (P < 0.01), whereas revascularization (D, phRV) was not (P > 0.05). (E–J) Monocyte adhesion was observed just before and during pathological neovascularization (H–J). Green fluorescence from the anti-CD13 antibody (E and H) and red fluorescence from the rhodamine-coupled Con A (F and I) identifies the Con A–stained cells as being CD13-positive leukocytes (arrows) when the images were superimposed (G and J). (K) Monocyte VEGF mRNA expression in normoxia (21% oxygen) and hypoxia (1% oxygen). VEGF levels were markedly increased in response to hypoxic stimulation. Bars: (E–J) 50 μm; (A and B) 0.5 mm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2194095&req=5

fig4: Role of monocytes in pathological retinal neovascularization. (A) Pathological neovascularization (arrows, D7) treated with PBS control-liposomes (n = 8) was not inhibited. (B) Pathological neovascularization (arrows, D7) treated with clodronate-liposomes (n = 8). Notably, the pathological neovascular budding (C, PaNV) was suppressed (P < 0.01), whereas revascularization (D, phRV) was not (P > 0.05). (E–J) Monocyte adhesion was observed just before and during pathological neovascularization (H–J). Green fluorescence from the anti-CD13 antibody (E and H) and red fluorescence from the rhodamine-coupled Con A (F and I) identifies the Con A–stained cells as being CD13-positive leukocytes (arrows) when the images were superimposed (G and J). (K) Monocyte VEGF mRNA expression in normoxia (21% oxygen) and hypoxia (1% oxygen). VEGF levels were markedly increased in response to hypoxic stimulation. Bars: (E–J) 50 μm; (A and B) 0.5 mm.
Mentions: To investigate the role of monocytes in pathological neovascularization, clodronate-liposomes were used to inactivate monocyte lineage cells. Compared with PBS-liposomes (Fig. 4 A), monocyte-selective depletion (Fig. 4 B) led to a significant suppression of pathological neovascularization (Fig. 4 C), but had negligible effect on revascularization (Fig. 4 D). Immunohistochemistry confirmed that a subset of the adherent leukocytes in the vasculature (Fig. 4, E–J) were positive for CD13, aminopeptidase N coexpressed with MHC-II for monocyte-surface antigen processing. RT-PCR showed that circulating monocytes isolated from rats with proliferative retinopathy expressed VEGF120 and VEGF164, which was markedly induced after hypoxic stimulation (Fig. 4 K).

Bottom Line: These data highlight important molecular and cellular differences between physiological and pathological retinal neovascularization.These processes provide positive and negative angiogenic regulation, respectively.Together, new therapeutic approaches for selectively targeting pathological, but not physiological, retinal neovascularization are outlined.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Boston 02114, USA.

ABSTRACT
Hypoxia-induced VEGF governs both physiological retinal vascular development and pathological retinal neovascularization. In the current paper, the mechanisms of physiological and pathological neovascularization are compared and contrasted. During pathological neovascularization, both the absolute and relative expression levels for VEGF164 increased to a greater degree than during physiological neovascularization. Furthermore, extensive leukocyte adhesion was observed at the leading edge of pathological, but not physiological, neovascularization. When a VEGF164-specific neutralizing aptamer was administered, it potently suppressed the leukocyte adhesion and pathological neovascularization, whereas it had little or no effect on physiological neovascularization. In parallel experiments, genetically altered VEGF164-deficient (VEGF120/188) mice exhibited no difference in physiological neovascularization when compared with wild-type (VEGF+/+) controls. In contrast, administration of a VEGFR-1/Fc fusion protein, which blocks all VEGF isoforms, led to significant suppression of both pathological and physiological neovascularization. In addition, the targeted inactivation of monocyte lineage cells with clodronate-liposomes led to the suppression of pathological neovascularization. Conversely, the blockade of T lymphocyte-mediated immune responses with an anti-CD2 antibody exacerbated pathological neovascularization. These data highlight important molecular and cellular differences between physiological and pathological retinal neovascularization. During pathological neovascularization, VEGF164 selectively induces inflammation and cellular immunity. These processes provide positive and negative angiogenic regulation, respectively. Together, new therapeutic approaches for selectively targeting pathological, but not physiological, retinal neovascularization are outlined.

Show MeSH
Related in: MedlinePlus