Ocular Sarcoidosis Limited to Retinal Vascular Ischemia and Neovascularization.

A 59-year-old Caucasian male experienced progressive vision loss secondary to retinal vascular ischemia and neovascularization. At no time did he present with uveitis or vasculitis, and his serology tests were all negative. He was soon after diagnosed with sarcoidosis by hilar lymph node lung biopsy. Our patient demonstrates an atypical presentation of ocular sarcoidosis, manifesting solely as neovascularization and retinal vascular ischemia. Ophthalmologists should consider proliferative sarcoid retinopathy in patients with neovascularization.

A rare case of odontogenic parainfectious intraorbital optic neuritis with the absence of clinical manifestation of orbital cellulitis.

PURPOSE: To report the case of a 67-year-old male patient with odontogenic maxillary sinusitis who presented with unilateral parainfectious intraorbital optic neuritis without clinical signs and symptoms suggestive of orbital cellulitis. Despite the absence of clinical signs, taking a thorough history and obtaining the appropriate neuroimaging study raised the suspicion for an infectious etiology as the cause of optic neuropathy and stopped the continuation of corticosteroid treatment. METHODS: Retrospective case report. RESULTS: The only abnormal findings in the ophthalmic examination were acute decrease visual acuity, inferior visual field loss, and the presence of a relative afferent pupillary defect. A gadolinium contrast-enhanced magnetic resonance imaging scan showed ill-defined diffuse enhancement of the left intraorbital optic nerve and sheath with mild perineural fat stranding and enlargement of the inferior rectus muscle. There was also complete opacification of the ipsilateral maxillary sinus with peripheral enhancement, suggestive of a sinus abscess. CONCLUSION: Prompt arrival to the diagnosis led to expedient implementation of treatment comprising of broad-spectrum intravenous antibiotics and maxillary sinus irrigation by otolaryngology ultimately resulted in restoring the patient's vision back to baseline with complete resolution of the relative afferent pupillary defect.

HIV-1 tat protein induces a migratory phenotype in human fetal microglia by a CCL2 (MCP-1)-dependent mechanism: possible role in NeuroAIDS.

Acquired immune deficiency syndrome (AIDS) encephalitis and dementia are characterized by neuronal loss, astrogliosis, and microglia activation and migration that contribute to the formation of multinucleated giant cells. Despite extensive evidence of pathological changes in the brain of infected individuals, the mechanisms of human immune deficiency virus type 1 (HIV-1) entry, microglia migration, and viral propagation within the brain are still not completely understood. In this study, we report that the induction of a migratory phenotype in human fetal microglia by the HIV-1 transactivator protein, tat, is mediated by the chemokine, CCL2. CCL2 or tat treatment alone induced rearrangement of actin and the formation of microglial processes. The time course of cell membrane ruffling induced by CCL2 was faster (5-30 min) than that elicited by tat treatment (2-3 h). Our previous data in human fetal microglia showed that tat induces CCL2 expression. Thus, we examined whether tat-induced microglia membrane ruffling and process formation, critical components in cell migration, are mediated by the secretion of CCL2 by these cells. To test this hypothesis, we treated microglia with tat protein in the presence of neutralizing CCL2 antibodies. Co-treatment with neutralizing CCL2 antibodies resulted in the loss of tat-induced membrane ruffling. Tat treatment of microglia induced polarization of CCR2, the receptor for CCL2, to the leading edge of processes, further suggesting a CCL2-dependent mechanism of tat-induced microglia migration. Our data indicate that tat facilitates microglia migration by inducing autocrine CCL2 release. Our results suggest that tat induced CCL2 secretion may be one of the early signals during NeuroAIDS.

Retina-specific expression of PDGF-B versus PDGF-A: vascular versus nonvascular proliferative retinopathy.

PURPOSE: Platelet-derived growth factor (PDGF) has been implicated in vascular proliferative retinopathies, such as diabetic retinopathy, and in nonvascular retinopathies, such as proliferative vitreoretinopathy. Traction retinal detachment is a central feature of both types of disease. Hemizygous rhodopsin promoter/PDGF-B (rho/PDGF-B) transgenic mice exhibit proliferation of vascular cells, glia, and retinal pigmented epithelial (RPE) cells, resulting in traction retinal detachment. Hemizygous rho/PDGF-A transgenic mice show mild proliferation of glial cells and no traction retinal detachments. This study was undertaken to determine whether higher levels of endogenously produced PDGF-A in the retinas of mice result in retinal detachment. METHODS: To achieve high-level expression of PDGF-A in the retina, homozygous rho/PDGF-A (rho/PDGF-AA) mice were generated. The phenotype of these mice was compared with that of homozygous rho/PDGF-B (rho/PDGF-BB) mice and double hemizygous rho/PDGF-B-rho/PDGF-A (rho/PDGF-AB) mice. RESULTS: Rho/PDGF-BB and rho/PDGF-AB mice showed a phenotype similar to that previously described in rho/PDGF-B mice. There was extensive proliferation of glial and vascular cells, resulting in fibrovascular membranes that detached the retina. PDGF-AA mice showed extensive proliferation of glial cells and traction retinal detachment. CONCLUSIONS: High retinal expression of PDGF-A results in extensive proliferation of glial cells and traction retinal detachment without vascular cell involvement, similar to proliferative vitreoretinopathy in humans. High retinal expression of PDGF-B results in traction retinal detachment from proliferation of both vascular and nonvascular cells, similar to diabetic retinopathy in humans.