Dimosthenis Mantopoulos

The Role of LAT in Increased CD8+ T Cell Exhaustion in Trigeminal Ganglia of Mice Latently Infected with Herpes Simplex Virus 1

ABSTRACT Herpes simplex virus (HSV) infection is a classic example of latent viral infection in humans and experimental animal models. The HSV-1 latency-associated transcript (LAT) plays a major role in the HSV-1 latency reactivation cycle and thus in recurrent disease. Whether the presence of LAT leads to generation of dysfunctional T cell responses in the trigeminal ganglia (TG) of latently infected mice is not known. To address this issue, we used LAT-positive [LAT(+)] and LAT-deficient [LAT(−)] viruses to evaluate the effect of LAT on CD8 T cell exhaustion in TG of latently infected mice. The amount of latency as determined by quantitative reverse transcription-PCR (qRT-PCR) of viral DNA in total TG extracts was 3-fold higher with LAT(+) than with LAT(−) virus. LAT expression and increased latency correlated with increased mRNA levels of CD8, PD-1, and Tim-3. PD-1 is both a marker for exhaustion and a primary factor leading to exhaustion, and Tim-3 can also contribute to exhaustion. These results suggested that LAT(+) TG contain both more CD8+ T cells and more CD8+ T cells expressing the exhaustion markers PD-1 and Tim-3. This was confirmed by flow cytometry analyses of expression of CD3/CD8/PD-1/Tim-3, HSV-1, CD8+ T cell pentamer (specific for a peptide derived from residues 498 to 505 of glycoprotein B [gB498–505]), interleukin-2 (IL-2), and tumor necrosis factor alpha (TNF-α). The functional significance of PD-1 and its ligands in HSV-1 latency was demonstrated by the significantly reduced amount of HSV-1 latency in PD-1- and PD-L1-deficient mice. Together, these results may suggest that both PD-1 and Tim-3 are mediators of CD8+ T cell exhaustion and latency in HSV-1 infection.

Tauroursodeoxycholic acid (TUDCA) protects photoreceptors from cell death after experimental retinal detachment.

Background Detachment of photoreceptors from the underlying retinal pigment epithelium is seen in various retinal disorders such as retinal detachment and age-related macular degeneration and leads to loss of photoreceptors and vision. Pharmacologic inhibition of photoreceptor cell death may prevent this outcome. This study tests whether systemic administration of tauroursodeoxycholic acid (TUDCA) can protect photoreceptors from cell death after experimental retinal detachment in rodents. Methodology/Principal Findings Retinal detachment was created in rats by subretinal injection of hyaluronic acid. The animals were treated daily with vehicle or TUDCA (500 mg/kg). TUNEL staining was used to evaluate cell death. Photoreceptor loss was evaluated by measuring the relative thickness of the outer nuclear layer (ONL). Macrophage recruitment, oxidative stress, cytokine levels, and caspase levels were also quantified. Three days after detachment, TUDCA decreased the number of TUNEL-positive cells compared to vehicle (651±68/mm2 vs. 1314±68/mm2, P = 0.001) and prevented the reduction of ONL thickness ratio (0.84±0.03 vs. 0.65±0.03, P = 0.002). Similar results were obtained after 5 days of retinal detachment. Macrophage recruitment and expression levels of TNF-a and MCP-1 after retinal detachment were not affected by TUDCA treatment, whereas increases in activity of caspases 3 and 9 as well as carbonyl-protein adducts were almost completely inhibited by TUDCA treatment. Conclusions/Significance Systemic administration of TUDCA preserved photoreceptors after retinal detachment, and was associated with decreased oxidative stress and caspase activity. TUDCA may be used as a novel therapeutic agent for preventing vision loss in diseases that are characterized by photoreceptor detachment.

In Vivo Imaging of Corneal Inflammation: New Tools for Clinical Practice and Research

Purpose: Infectious and inflammatory corneal diseases are a major cause of blindness. To date, assessment of corneal inflammation, has only been possible by slit-lamp biomicroscopy. The purpose of this study is to review the current state of imaging technologies enabling in vivo imaging of inflammation in the cornea. Methods: Literature review of peer-reviewed articles on in vivo imaging modalities. Results: Current means of diagnosis and treatment follow-up for immune and infectious keratitis are limited to slit-lamp biomicroscopy. Several modalities are currently emerging, allowing for in vivo imaging of corneal inflammation, including in vivo confocal microscopy, anterior segment optical coherence tomography, and intravital multiphoton microscopy. Conclusion: Several in vivo imaging technologies are currently evolving, allowing for objective assessment of corneal inflammation and treatment response.

Evidence for baseline retinal pigment epithelium pathology in the Trp1-Cre mouse

The increasing popularity of the Cre/loxP recombination system has led to the generation of numerous transgenic mouse lines in which Cre recombinase is expressed under the control of organ- or cell-specific promoters. Alterations in retinal pigment epithelium (RPE), a multifunctional cell monolayer that separates the retinal photoreceptors from the choroid, are prevalent in the pathogenesis of a number of ocular disorders, including age-related macular degeneration. To date, six transgenic mouse lines have been developed that target Cre to the RPE under the control of various gene promoters. However, multiple lines of evidence indicate that high levels of Cre expression can be toxic to mammalian cells. In this study, we report that in the Trp1-Cre mouse, a commonly used transgenic Cre strain for RPE gene function studies, Cre recombinase expression alone leads to RPE dysfunction and concomitant disorganization of RPE layer morphology, large areas of RPE atrophy, retinal photoreceptor dysfunction, and microglial cell activation in the affected areas. The phenotype described herein is similar to previously published reports of conditional gene knockouts that used the Trp1-Cre mouse, suggesting that Cre toxicity alone could account for some of the reported phenotypes and highlighting the importance of the inclusion of Cre-expressing mice as controls in conditional gene targeting studies.

Bilateral Choroidopathy and Serous Retinal Detachments During Ipilimumab Treatment for Cutaneous Melanoma.

Several immune-related toxic effects have been reported with ipilimumab therapy for cutaneous melanoma. We describe a novel reaction, to our knowledge, involving the choroidal vasculature and resulting in bilateral serous retinal detachments without overt inflammatory signs.

Multimodal Imaging of Spontaneously Shifting Primary Vitreoretinal Lymphoma

Purpose: To correlate spectral domain optical coherence tomography (SD-OCT) and photographic imaging before and after spontaneous regression of primary vitreoretinal lymphoma (PVRL) lesions. Procedures: We report the case of a 60-year-old female. Results: The patient presented with bilateral creamy deposits under the retina and retinal pigment epithelium (RPE), and lesions were visible along Bruchs membrane with SD-OCT and suspicious for PVRL. Systemic workup revealed nonspecific areas of enhancement on neuroimaging. The patient was largely asymptomatic and the decision was made to observe her. Three months later, a new lesion pattern had developed. The color fundus photographs and SD-OCT demonstrated spontaneous regression of the largest sub-RPE lesion, leaving areas of RPE atrophy, while a new larger sub-RPE lesion had formed in the other eye. Vitreous biopsy showed lymphocytes and no malignant cells, while sub-RPE biopsy of the newly formed lesion revealed highly atypical cells positive for CD19 and CD20. Conclusions: Multimodal imaging documents that PVRL lesion regression and early RPE changes can develop within a 3-month period. Immune control is an important factor in lesion regression in the eye.

Isolated Bilateral Fourth Cranial Nerve Palsies as the Presenting Sign of Hydrocephalus

Midbrain lesions leading to bilateral fourth nerve palsies are typically accompanied by other brainstem symptomatology. Here we report a case of a 29-year-old man with hydrocephalus and significant third ventricle dilation applying pressure on the dorsal midbrain and having as the only manifestation isolated, bilateral fourth cranial nerve palsies. This finding, reported here for the first time, could be attributed to a partially working ventriculoperitoneal shunt previously placed in this patient, which was able to sporadically relieve the increases of the intraventricular pressure on the midbrain that would normally lead to other manifestations.

MIF Inhibitor ISO-1 Protects Photoreceptors and Reduces Gliosis in Experimental Retinal Detachment

Photoreceptor death and retinal gliosis underlie the majority of vision threatening retinal diseases including retinal detachment (RD). Although the underlying pathobiology of vision limiting processes in RD is not fully understood, inflammation is known to play a critical role. We conducted an iTRAQ proteomic screen of up- and down-regulated proteins in a murine model of RD to identify potential targetable candidates. Macrophage migration inhibitory factor (MIF) was identified and evaluated for neurotoxic and pro-gliotic effects during RD. Systemic administration of the MIF inhibitor ISO-1 significantly blocked photoreceptor apoptosis, outer nuclear layer (ONL) thinning, and retinal gliosis. ISO-1 and MIF knockout (MIFKO) had greater accumulation of Müller glia pERK expression in the detached retina, suggesting that Müller survival pathways might underlie the neuroprotective response. Our data show the feasibility of the MIF-inhibitor ISO-1 to block pathological damage responses in retinal detachment and provide a rationale to explore MIF inhibition as a potential therapeutic option for RD.

Recurrent Vitreous Hemorrhage Secondary to Sulcus Positioning of a One-Piece Acrylic Intraocular Lens Haptic: Report of 3 Cases and Management With Retrocapsular Haptic Repositioning:

Three pseudophakic patients presented with recurrent, unilateral vitreous hemorrhage, one of which also had uveitis, glaucoma, and hyphema, consistent with “uveitis–glaucoma–hyphema (UGH)-Plus” syndrome. Arcuate transillumination defects secondary to inadvertent placement of 1 intraocular lens (IOL) haptic in the sulcus were identified in each case. The second haptic and optic were located in the capsular bag. The IOLs were all single-piece foldable acrylic lenses with square-edge haptic design. Surgical repositioning of the malpositioned haptic from the sulcus to the retrocapsular space resulted in the resolution of the recurrent vitreous hemorrhage. This series highlights the fact that recurrent vitreous hemorrhage secondary to iris chafing, with or without UGH, may occur in cases where a square-edge IOL haptic is placed in the sulcus. Vitrectomy with repositioning of the malpositioned IOL is a simple alternative to IOL exchange in these cases.

Bilateral optic neuropathy following bite from brown recluse spider (Loxosceles reclusa).

Abstract A 63-year-old female with history of a resected frontal lobe meningioma presented with bilaterally decreased vision after a bite from a brown recluse spider. The exam was significant for a left relative afferent pupillary defect, bilateral optic nerve pallor, decreased foveal sensitivity in the left eye and new bilateral visual field defects, despite stability of her meningioma. The findings remained stable at 1-year follow-up. To our knowledge, this is the first reported case of optic neuropathy secondary to a brown recluse spider bite. Visual field tests performed prior to the bite allowed us to compare and localize changes related to the bite.