Occlusion of retinal capillaries caused by glial cell proliferation in chronic ocular inflammation.

The inner blood-retinal barrier is a gliovascular unit in which glial cells surround capillary endothelial cells and regulate retinal capillaries by paracrine interactions. During chronic ocular inflammation, microvascular complications can give rise to vascular proliferative lesions, which compromise visual acuity. This pathologic remodelling caused by proliferating Müller cells determines occlusion of retinal capillaries. The aim of the present study was to identify qualitative and quantitative alterations in the retinal capillaries in patients with post-traumatic chronic ocular inflammation or post-thrombotic vascular glaucoma. Moreover, we investigated the potential role of vascular endothelial growth factor (VEGF) and pro-inflammatory cytokines in retinal inflammation. Our electron microscopy findings demonstrated that during chronic ocular inflammation, thickening of the basement membrane, loss of pericytes and endothelial cells and proliferation of Müller cells occur with irreversible occlusion of retinal capillaries. Angiogenesis takes place as part of a regenerative reaction that results in fibrosis. We believe that VEGF and pro-inflammatory cytokines may be potential therapeutic targets in the treatment of this disease although further studies are required to confirm these findings.

Idiopathic juxtafoveal retinal telangiectasis and retinal macroaneurysm treated with indocyanine green dye-enhanced photocoagulation.

This case report presents the use of indocyanine green dye-enhanced photocoagulation (ICG-DEP) for the treatment of idiopathic juxtafoveal retinal telangiectasis and a retinal macroaneurysm. A 35-year-old male with 20/20 vision had been followed for 5 years for a retinal macroaneurysm with retinal telangiectasis outside the macular area. He then presented with a recently decreased vision in his right. He had macular edema with a new area of idiopathic juxtafoveal retinal telangiectasis. After 4 focal argon laser treatments, angiographic closure of the lesions was not obtained and the retinal edema remained. After 3 sessions of ICG-DEP, the lesions were closed and the edema absorbed. The 810 nm infrared laser with ICG-DEP should be considered for the treatment of idiopathic juxtafoveal retinal telangiectasis and retinal macroaneurysms. In this case the procedure appears to be safe and well tolerated. It may allow for more direct energy absorption than that of the argon laser to these types of retinal lesions with better tissue closure.

The effect of latanoprost and influence of changes in body position on patients with glaucoma and ocular hypertension.

BACKGROUND AND OBJECTIVES: Some patients have an elevation of intraocular pressure (IOP) in the supine position (IOPSP). It has been suggested that topical latanoprost 0.005% (LP) has an attenuating effect on these IOP elevations. The Authors report a simple procedure to evaluate the change in the IOPSP. This paper presents the results of the change in the IOPSP in normals, in patients with ocular hypertension (OH) and in patients with primary open angle glaucoma (POAG). The study also evaluates the effect of the addition of topical LP on those patients with an elevation of their IOPSP. PATIENTS AND METHODS: Part 1 evaluated the change in the IOPSP in the morning in 40 eyes of normals, 82 eyes in patients with OH and 77 eyes in patients with POAG. The IOP was measured before and after lying in the supine position (SP) for 90 minutes. In part 2 the patients with OH or POAG with an increase in their IOPSP were selected and the test was repeated again after the addition of topical LP. RESULTS: When compared with normals, the patients with OH and POAG had significantly greater IOPSP increases. The patients with POAG had significantly greater IOPSP increases than did those with OH. The addition of LP partially decreased but did not eliminate the IOP increases in the SP. CONCLUSIONS: Patients with OH and POAG have a larger increase in their IOPSP than do normals. The addition of topical LP partially decreased but did not totally eliminate these pressure increases.

Immunohistochemical profile of VEGF, TGF-ß and PGE2 in human pterygium and normal conjunctiva: experimental study and review of the literature.

Human pterygium is made up of chronic proliferative fibro-vascular tissue growing on the ocular surface. This disease exhibits both degenerative and hyperplastic properties. Some fibroangiogenic factors have recently been shown to play a potential role in fibrovascular diseases via the angiogenesis process. The aim of this study is to evaluate VEGF, TGF-ß and PGE2 expression in the epithelial, endothelial and stromal cells of human pterygium and normal conjunctiva in order to determine whether these factors participate in the development of pterygium. Ten specimens from patients with pterygium and two normal conjunctivas (cadavers) were analyzed by immunohistochemistry using specific antibodies against these growth factors. The technique used was ABC/HRP (Avidin complexed with biotinylated peroxidase). Immunoreactivity of VEGF was significantly increased in the epithelium, vascular endothelium and stromal cells in primary pterygium as compared with normal conjunctiva. A moderate expression of TGF-ß in the pterygium was observed in the epithelial and stromal layers. On the contrary, immunolabeling of this growth factor in the human normal conjunctiva was weak. PGE2 was strongly expressed in the epithelium of patients with pterygium, as in control conjunctival tissues, and the immunolabeling was moderate in the stroma from the same patients. Our results suggest that these growth factors may contribute to the progression of primary pterygium by increasing angiogenesis, thus leading to the formation of new blood vessels from the pre-existing vasculature. We conclude that VEGF, TGF-ß and PGE2 may be potential therapeutic targets in the treatment of this disease although proof of this evidence requires further studies.