Hypoxia up-regulates CD36 expression and function via hypoxia-inducible factor-1- and phosphatidylinositol 3-kinase-dependent mechanisms.

Neovascular and degenerative diseases of the eye are leading causes of impaired vision and blindness in the world. Hypoxia or reduced oxygen tension is considered central to the pathogenesis of these disorders. Although the CD36 scavenger receptor features prominently in ocular homeostasis and pathology, little is known regarding its modulation by hypoxia.

Emerging roles for the CD36 scavenger receptor as a potential therapeutic target for corneal neovascularization.

Neovascularization (NV) of the normally avascular cornea arises from various causes including inflammation, infection, trauma, and contact lens wear. Corneal NV, whatever the cause, impairs vision and threatens the survival of corneal allografts, thus representing a serious clinical problem for which treatment is limited. Recent interest has focused on vascular endothelial growth factor (VEGF), a key angiogenic factor whose role in corneal NV is amply documented.

The role of lysophosphatidic acid receptor (LPA1) in the oxygen-induced retinal ganglion cell degeneration.

Purpose: Although previous studies have demonstrated that hypoxia induces retinal ganglion cell (RGC) apoptosis and that transient retinal ischemia upregulates the expression of lysophosphatidic acid (LPA) receptors, it remains to be determined whether LPA(1) receptor mediates RGC degeneration during retinopathy of prematurity (ROP). By using an immortalized RGC line (RGC-5), primary neonatal RGC cultures, and oxygen-induced retinopathy (OIR) to model ROP, the authors explored whether LPA(1) receptor induces RGC degeneration and the potential mechanisms thereof.

Methods: OIR was induced by exposing rat pups to alternating cycles of hyperoxia/hypoxia from postnatal day (P) 0 to P14.

Genetic ablation of CD36 induces age-related corneal neovascularization.

Purpose: Corneal avascularity is tightly regulated by a balance between angiogenic and antiangiogenic factors (angiogenic privilege). In the current study, we tested the hypothesis that the CD36+/+ antiangiogenic receptor contributes toward the maintenance of corneal avascularity.

Methods: Corneas of CD36 wild-type (CD36) and knockout (CD36) mice aged 4, 16, 52, and 78 weeks were histologically evaluated for corneal haze and neovascularization (NV).

Lymphocytic microparticles inhibit angiogenesis by stimulating oxidative stress and negatively regulating VEGF-induced pathways.

Recent studies have demonstrated that lymphocyte-derived microparticles (LMPs) impair endothelial cell function. However, no data currently exist regarding the contribution of LMPs in the regulation of angiogenesis. In the present study, we investigated the effects of LMPs on angiogenesis in vivo and in vitro and demonstrated that LMPs strongly suppressed aortic ring microvessel sprouting and in vivo corneal neovascularization.

Activation of CD36 inhibits and induces regression of inflammatory corneal neovascularization.

Purpose: This study was undertaken to investigate the role of the antiangiogenic receptor CD36 during inflammatory corneal neovascularization (CNV).

Methods: In a murine model of inflammatory CNV, CD36 expression was evaluated by RT-PCR and immunofluorescence. Mice subjected to CNV were treated topically (thrice daily) with CD36 functionally neutralizing antibodies against the oxidized low-density lipoprotein (oxLDL) and thrombospondin (TSP)-1 sites (clones JC63.

Inflammatory lipid mediators in ischemic retinopathy.

Ischemic proliferative retinopathy develops in various retinal disorders, including retinal vein occlusion, diabetic retinopathy and retinopathy of prematurity. Ischemic retinopathy remains a common cause of visual impairment and blindness in the industrialized world due to relatively ineffective treatment. Oxygen-induced retinopathy (OIR) is an established model of retinopathy of prematurity associated with vascular cell injury culminating in microvascular degeneration, which precedes an abnormal neovascularization.

New insights into the retinal circulation: inflammatory lipid mediators in ischemic retinopathy.

Ischemic proliferative retinopathy develops in various retinal disorders, including retinal vein occlusion, diabetic retinopathy and retinopathy of prematurity. Ischemic retinopathy remains a common cause of visual impairment and blindness in the industrialized world due to relatively ineffective treatment. Oxygen-induced retinopathy (OIR) is an established model of retinopathy of prematurity associated with vascular cell injury culminating in microvascular degeneration, which precedes an abnormal neovascularization.

Cyclooxygenase-2 in human and experimental ischemic proliferative retinopathy.

Background: Intravitreal neovascular diseases, as in ischemic retinopathies, are a major cause of blindness. Because inflammatory mechanisms influence vitreal neovascularization and cyclooxygenase (COX)-2 promotes tumor angiogenesis, we investigated the role of COX-2 in ischemic proliferative retinopathy.

Methods And Results: We describe here that COX-2 is induced in retinal astrocytes in human diabetic retinopathy, in the murine and rat model of ischemic proliferative retinopathy in vivo, and in hypoxic astrocytes in vitro.