Bilateral, Simultaneous Central Serous Chorioretinopathy in Association With Oral Contraception Use.

This report describes a case of bilateral, simultaneous central serous chorioretinopathy (CSCR) in a young woman on oral contraceptive pills (OCP). A 21-year-old woman with a negative past medical history presented with sudden onset of bilateral decreased vision shortly after starting OCP. Comprehensive ocular examination revealed bilateral central serous chorioretinopathy (CSCR), confirmed on retinal optical coherence tomography (OCT) and intravenous fluorescein angiography. The patient was instructed to discontinue OCP, and three weeks later, there was complete resolution of the visual symptoms and of the bilateral serous retinal detachments, documented on OCT. [Ophthalmic Surg Lasers Imaging Retina 2024;55:96-99.].

A Rare Case of Vomiting-Induced Retrobulbar Hemorrhage.

Retrobulbar hemorrhage may result in sudden accumulation of blood in the retrobulbar space which can lead to an orbital compartment syndrome. This potentially blinding condition is characterized by a rapid increase in intra-orbital pressure. While most commonly associated with orbital trauma, it may rarely occur with Valsalva events in patients on anticoagulants. In this report, we present a case of a retrobulbar hemorrhage secondary to self-induced vomiting, occurring in a patient on no anticoagulation medication.

Necroptosis, a novel form of caspase-independent cell death, contributes to neuronal damage in a retinal ischemia-reperfusion injury model.

UNLABELLED: Necroptosis is programmed necrosis triggered by death receptor signaling. We investigated whether necroptosis contributes to neuronal damage and functional impairment in a model of retinal ischemia. METHODS: Sprague-Dawley rats were subjected to raised intra-ocular pressure for 45 min and received intravitreal injections of the specific necroptosis inhibitor, Nec-1, its inactive analogue (Nec-1i) or vehicle. Seven days after ischemia, ERGs were performed and then the eyes were enucleated for histological analysis. In other animals, retinas were subjected to propodium iodide, TUNEL staining or Western Blotting and probed with anti-LC-3 antibody. RESULTS: Retinal ischemia resulted in selective neuronal degeneration of the inner layers. Pretreatment with Nec-1 led to significant preservation in thickness and histoarchitecture of the inner retina and functional improvement compared with vehicle-treated controls. Pretreatment with Nec-1i did not provide histological or functional protection. Post-treatment with Nec-1 also significantly attenuated the ERG b-wave reduction compared with ischemic vehicle controls. Nec-1 had no effect on the number of caspase or TUNEL-labelled cells in the ischemic retina but did inhibit the induction of LC-3 II and reduced the number of PI-labelled cells after ischemia. CONCLUSION: Necroptosis is an important mode of neuronal cell death and involves autophagy in a model of retinal ischemia.

EDG receptors as a potential therapeutic target in retinal ischemia-reperfusion injury.

LPA (lysophosphatidic acid) specific endothelial differentiation gene (EDG) receptors have been implicated in various anti-apoptotic pathways. Ischemia of the brain and retina causes neuronal apoptosis, which raises the possibility that EDG receptors participate in anti-apoptotic signaling in ischemic injury. We examined the expression of EDG receptors in a model of retinal ischemia-reperfusion injury and also tested LXR-1035, a novel analogue of LPA, in the rat following global retinal ischemic injury. Rats were subjected to 45 or 60 min of raised intraocular pressure. Animals were sacrificed at 24 h post-ischemia and retinal tissue was stained for EDG receptors. In separate experiments, animals were randomized to receive LXR or saline vehicle by intravitreal injection 24 h prior to ischemia. The degree of retinal damage was assessed morphologically by measuring the thickness of the inner retinal layers as well as functionally by electroretinography (ERG). We found that the normal retina has a baseline expression of the LPA receptors, EDG-2 and EDG-4, which are significantly upregulated in the inner layers in response to ischemia. Animals pretreated with LXR-1035 had dose-dependent, significant reductions in histopathologic damage and significant improvement in functional deficits compared with corresponding vehicle-controls, after 45 and 60 min of ischemia. These results suggest that LPA receptor signaling may play an important role in neuroprotection in retinal ischemia-reperfusion injury.

Ischemic preconditioning attenuates apoptotic cell death in the rat retina.

PURPOSE: Ischemic preconditioning (IPC) protects the rat retina against the injury that ordinarily follows prolonged ischemia. It has been shown that release of adenosine, de novo protein synthesis, and mediators, such as protein kinase C and K(ATP) channels, is required for IPC protection. However, the molecular mechanisms of neuroprotection by IPC are unknown. Retinal cells die after ischemia by necrosis and apoptosis. This study was undertaken to investigate the effect of IPC on apoptosis after ischemia and some of the key proteins involved in the apoptotic cascade. METHODS: Retinal ischemia or IPC was produced in anesthetized Sprague-Dawley rats by increasing intraocular pressure above systolic arterial pressure. Retinal ischemia was induced 24 hours after either IPC or sham IPC. TUNEL staining was used to quantitate the number of cells with DNA fragmentation. The authors examined expression of cleaved forms of caspases-2 and -3, bax, and poly-adenosine diphosphate-ribose-polymerase (PARP) by Western blot analysis for evidence of apoptosis-related gene expression. To examine possible mechanisms of apoptosis after ischemia, the authors studied the expression of mitogen-activated protein kinases (MAP kinases). Functional recovery after ischemia was measured using electroretinography, and retinal histology was examined and quantitated by light microscopy. RESULTS: Positive TUNEL staining, increases in caspase-2 and -3 cleavage, expression of bax and PARP, and activation of MAP kinases were found with ischemia. IPC attenuated these changes, but paradoxically, IPC itself triggered increased expression of MAP kinases. CONCLUSIONS: IPC protects against ischemic injury, in part, by diminishing apoptosis-related gene expression and by altering protein phosphorylation.

Poststreptococcal keratouveitis associated with group C streptococcus pharyngitis.

PURPOSE: To report the first case of poststreptococcal syndrome uveitis (PSU) in association with group C streptococcus (GCS). PATIENTS AND METHODS: Chart review of a 24-year-old man who presented with bilateral ocular redness, pain, and photophobia for 5 days and "white rings" around his eyes for a duration of 3 days. The patient further reported fever and sore throat in the preceding week. Slit-lamp examination showed bilateral keratouveitis. A thorough uveitis workup, antistreptolysin O (ASLO) titer, and throat culture were obtained. The patient was treated with frequent topical steroids and systemic doxycycline. The uveitis and keratitis subsided over the next few weeks, leaving extensive peripheral keratolysis. RESULTS: The results of laboratory diagnostic testing revealed an elevated ASLO, C-reactive protein, as well as HLA-B27 positivity. Throat cultures grew beta-hemolytic GCS; group A streptococcus was culture negative. CONCLUSION: GCS pharyngitis may be a causative organism of PSU.

A novel calpain inhibitor for treatment of transient retinal ischemia in the rat.

After an acute ischemia/reperfusion of the rat retina, the activation of cytotoxic proteases, including calpain, results in necrosis and apoptosis of retinal ganglion cells resulting in their degeneration. Using a systemically administered calpain inhibitor that crosses the blood-retinal barrier would provide for novel systemic intervention that protects the retina from acute injury and loss of function. Herein, we study a novel calpain peptide inhibitor, cysteic-leucyl-argininal (CYLA), in an in-vivo rat model of retinal ischemia to determine functional protection using electroretinography. The CYLA prodrug was administered intraperitoneally before and/or after ischemia-reperfusion at concentrations of 20-40 mg/kg. We found that administering 20 mg/kg of CYLA only after ischemia provides significant preservation of retinal function.

Branch retinal artery occlusion and non-ischemic central retinal vein occlusion due to hyperhomocysteinemia in a 14-year-old child.

A 14-year-old girl presented with sudden, painless loss of vision in the left eye. Complete ophthalmologic examination including fluorescein angiography revealed an impending central vein occlusion and a branch retinal artery occlusion inferotemporally. One month later, there was a non-ischemic central retinal vein occlusion of the same eye. Systemic evaluation led to the diagnosis of hyperhomocysteinemia. This case report underscores the importance of excluding hyperhomocysteinemia in vascular occlusive disease.

Deleterious role of TNF-alpha in retinal ischemia-reperfusion injury.

PURPOSE: Tumor necrosis factor (TNF)-alpha is a mediator of neuronal cell death and survival in ischemia-reperfusion injury. This study was conducted to further elucidate the role of TNF-alpha and its receptor in an in vivo model of retinal ischemia-reperfusion injury by investigating its effects on retinal histopathology and function. METHODS: Retinal ischemia-reperfusion injury was performed on p55 and p75 knockout (KO) mice and Sprague-Dawley rats using the high intraocular pressure METHOD: The temporal expression of TNF-alpha was ascertained with immunohistochemical staining. Separate rats received intravitreal recombinant TNF-alpha or neutralizing antibody before or after ischemia. TUNEL labeling was performed to assess for cell death, and electroretinography was performed to assess function. RESULTS: TNF-alpha expression peaked at 12 to 24 hours after ischemia-reperfusion injury. TUNEL staining was diminished after intravitreal TNF-alpha antibody. Both transgenic KOs demonstrated significantly less functional impairment. Rats receiving recombinant TNF-alpha 48 hours after ischemia showed exaggerated functional impairment. Animals treated with TNF-alpha antibody before ischemia displayed significant functional improvement. CONCLUSIONS: TNF-alpha plays a largely deleterious role in ischemia-reperfusion injury in an in vivo model of retinal injury. Direct neutralization of this cytokine partially preserves retinal function. The diverse characteristics of TNF-alpha are attributed in part to the timing of its expression after injury. TNF-alpha receptor expression and function, along with combination treatments targeting death receptor-mediated apoptosis, should be further explored to develop neuroprotective therapeutic strategies for acute retinal ischemic disorders.

Erythropoietin administration protects retinal neurons from acute ischemia-reperfusion injury.

Erythropoietin (EPO) plays an important role in the brain's response to neuronal injury. Systemic administration of recombinant human EPO (rhEPO) protects neurons from injury after middle cerebral artery occlusion, traumatic brain injury, neuroinflammation, and excitotoxicity. Protection is in part mediated by antiapoptotic mechanisms. We conducted parallel studies of rhEPO in a model of transient global retinal ischemia induced by raising intraocular pressure, which is a clinically relevant model for retinal diseases. We observed abundant expression of EPO receptor (EPO-R) throughout the ischemic retina. Neutralization of endogenous EPO with soluble EPO-R exacerbated ischemic injury, which supports a crucial role for an endogenous EPO/EPO-R system in the survival and recovery of neurons after an ischemic insult. Systemic administration of rhEPO before or immediately after retinal ischemia not only reduced histopathological damage but also promoted functional recovery as assessed by electroretinography. Exogenous EPO also significantly diminished terminal deoxynucleotidyltransferase-mediated dUTP end labeling labeling of neurons in the ischemic retina, implying an antiapoptotic mechanism of action. These results further establish EPO as a neuroprotective agent in acute neuronal ischemic injury.