TNF-alpha is critical for ischemia-induced leukostasis, but not retinal neovascularization nor VEGF-induced leakage.

Abstract

Vascular endothelial growth factor (VEGF) and tumor necrosis factor-alpha (TNF-alpha) show significant overlap with regard to their effects in the eye. It has been postulated that VEGF-induced leukostasis, breakdown of the blood-retinal barrier, and ischemia-induced retinal neovascularization may be mediated, at least in part, through TNF-alpha. In this study, we used mice deficient in TNF-alpha to test our hypothesis. Compared to wild type mice, TNF-alpha-deficient mice showed an 80% reduction in leukocyte accumulation in retinal vessels after intravitreous injection of VEGF, and 100% reductions after intravitreous injections of interleukin-1beta (IL-1beta) or platelet-activating factor (PAF). The increase in retinal vascular permeability induced by injection of PAF was significantly reduced in mice lacking TNF-alpha, but VEGF- and IL-1beta-induced leakage was unaffected. Compared to wild type mice with oxygen-induced ischemic retinopathy, TNF-alpha-deficient mice with ischemic retinopathy showed significantly reduced leukostasis and mild reduction in vascular leakage, but no significant difference in retinal neovascularization. These data suggest that TNF-alpha mediates VEGF-, IL-1beta-, and PAF-induced leukostasis and vascular leakage mediated by PAF, but not leakage caused by VEGF or IL-1beta. Ischemia-induced retinal neovascularization, which has previously been shown to require VEGF, does not require TNF-alpha and is unaffected by attenuation of leukostasis.

• Authors: Stanley A Vinores, Wei-Hong Xiao, Jikui Shen, Peter A Campochiaro
• Journal: Journal of neuroimmunology (J Neuroimmunol) Vol. 182 Issue 1-2 Pg. 73-9 (Jan 2007) ISSN: 0165-5728 [Print] Netherlands
• PMID: 17107717 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Interleukin-1beta
• Platelet Activating Factor
• Tumor Necrosis Factor-alpha
• Vascular Endothelial Growth Factor A
• Oxygen

Topics

• Animals
• Blood-Retinal Barrier (drug effects)
• Capillary Permeability (drug effects)
• Interleukin-1beta (pharmacology)
• Ischemia (chemically induced, complications, metabolism)
• Leukostasis (chemically induced, etiology)
• Mice
• Mice, Knockout
• Oxygen
• Platelet Activating Factor (pharmacology)
• Retinal Neovascularization (metabolism)
• Retinal Vessels
• Tumor Necrosis Factor-alpha (deficiency, metabolism, pharmacology)
• Vascular Endothelial Growth Factor A (metabolism, pharmacology)