Inhibition of Tumor Necrosis Factor-α Improves Physiological Angiogenesis and Reduces Pathological Neovascularization in Ischemic Retinopathy

Abstract

The present study was undertaken to test whether inhibition of the proangiogenic inflammatory cytokine tumor necrosis factor (TNF)-alpha can modulate retinal hypoxia and preretinal neovascularization in a murine model of oxygen-induced retinopathy (OIR). OIR was produced in TNF-alpha-/- and wild-type (WT) control C57B6 neonatal mice by exposure to 75% oxygen between postnatal days 7 and 12 (P7 to P12). Half of each WT litter was treated with the cytokine inhibitor semapimod (formerly known as CNI-1493) (5 mg/kg) by daily intraperitoneal injection from the time of reintroduction to room air at P12 until P17. The extent of preretinal neovascularization and intraretinal revascularization was quantified by image analysis of retinal flat-mounts and retinal hypoxia correlated with vascularization by immunofluorescent localization of the hypoxia-sensitive drug pimonidazole (hypoxyprobe, HP). HP adducts were also characterized by Western analysis and quantified by competitive enzyme-linked immunosorbent assay. TNF-alpha-/- and WT mice showed a similar sensitivity to hyperoxia-induced retinal ischemia at P12. At P13 some delay in early reperfusion was evident in TNF-alpha-/- and WT mice treated with semapimod. However, at P17 both these groups had significantly better vascular recovery with less ischemic/hypoxic retina and preretinal neovascularization compared to untreated retinopathy in WT mice. Immunohistochemistry showed deposition of HP in the avascular inner retina but not in areas underlying preretinal neovascularization, indicating that such aberrant vasculature can reduce retinal hypoxia. Inhibition of TNF-alpha significantly improves vascular recovery within ischemic tissue and reduces pathological neovascularization in OIR. HP provides a useful tool for mapping and quantifying tissue hypoxia in experimental ischemic retinopathy.

Phenotype-based Discovery of 2-[(E)-2-(Quinolin-2-yl)vinyl]phenol as a Novel Regulator of Ocular Angiogenesis

“…Analysis of Murine Retinal Vascularization-Flat-mounted retinas were fluorescently stained with Griffonia simplicifolia isolectin (B4) and Alexa-streptavidin 568 as reported previously (47). Eyes were coverslipped using Aqua/Polymount and imaged using a Zeiss Axiovert 200 M fluorescent microscope running Andor IQ2 software and stitched using Andor montaging.…”

MicroRNA 329 Suppresses Angiogenesis by Targeting CD146

“…6A). From P12 to P17, proangiogenic factors, including VEGF and TNF-␣, were produced in greatly increased amounts, causing severe pathological retinal vascular growth at P17 (4,37). To investigate the correlation of CD146 and miR-329 expression under pathological conditions in vivo, we analyzed their expression in normal and OIR-affected retinas, using quantitative realtime PCR.…”

The absence of LPA receptor 2 reduces the tumorigenesis by ApcMin mutation in the intestine

“…Hypoxyprobe-1 (pimonidazole) kit (HPI) was used to detect intestinal hypoxia in vivo. Mice were given hypoxyprobe solution (60 mg/kg ip) or PBS as vehicle control as previously described (10). After the injection (3 h), animals were killed, and intestinal sections were embedded in paraffin.…”