The Potential of Aqueous Humor Sampling in Diagnosis, Prognosis, and Treatment of Retinoblastoma.

Retinoblastoma (RB) is a rare malignant tumor that arises in the developing retina in one or both eyes of children. Pathogenic variants of the RB1 tumor suppressor gene drive the majority of germline and sporadic RB tumors. Considering the risk of tumor spread, the biopsy of RB tumor tissue is contraindicated. Advancement of chemotherapy has led to preservation of more eye globes. However, this has reduced access to tumor material from enucleation specimens. Recently, liquid biopsy of aqueous humor (AH) has advanced the RB tumor- or eye-specific genetic analysis. In particular, nucleic acid analysis of AH demonstrates the genomic copy number profiles and RB1 pathogenic variants akin to that of enucleated RB eye tissue. This advance reduces the previous limitation that genetic assessment of the primary tumor could be done only after enucleation of the eye. Additionally, nucleic acid evaluation of AH allows the exploration of the genomic landscape of RB tumors at diagnosis and during and after treatment. This review explores how AH sampling and AH nucleic acid analysis in RB patients assist in diagnosis, prognosis, and comprehending the pathophysiology of RB, which will ultimately benefit individualized treatment decisions to carefully manage this ocular cancer in children.

Temperature Change of Ophthalmic Viscosurgical Devices in a Bi-Chamber Set-Up at a Flow of 0 and 20mL/min.

Purpose: To understand the role of ophthalmic viscosurgical devices (OVDs) in corneal incision contracture (CIC). Specifically, the aim was to evaluate with the tip of the phacoemulsification needle free of OVD, how various OVDs near the tip and sleeve may transmit thermal energy to the incision site. Methods: A small chamber was filled with balanced saline solution (BSS), and a thin membrane was placed on the surface. OVD was placed atop the membrane. A temperature probe was placed in the OVD, while the handpiece pierced the membrane. The experiment was run both with and without flow and vacuum. Temperature measurements were gathered for each of the OVDs at four separate time points at 0 and 20mL/min flow. Results: As expected, there was a more pronounced temperature increase in all test groups with no fluid flow. While the temperature increase was not significantly different from BSS for any of the OVDs tested at either 0 or 20mL/min, Viscoat showed the most variable results at both flow settings. Conclusion: As long as the phaco tip is not in OVD, residual OVD near the incision is not exothermic and so not an additional risk for CIC.

PRMT5 is a therapeutic target in choroidal neovascularization.

Ocular neovascular diseases including neovascular age-related macular degeneration (nvAMD) are widespread causes of blindness. Patients' non-responsiveness to currently used biologics that target vascular endothelial growth factor (VEGF) poses an unmet need for novel therapies. Here, we identify protein arginine methyltransferase 5 (PRMT5) as a novel therapeutic target for nvAMD. PRMT5 is a well-known epigenetic enzyme. We previously showed that PRMT5 methylates and activates a proangiogenic and proinflammatory transcription factor, the nuclear factor kappa B (NF-κB), which has a master role in tumor progression, notably in pancreatic ductal adenocarcinoma and colorectal cancer. We identified a potent and specific small molecule inhibitor of PRMT5, PR5-LL-CM01, that dampens the methylation and activation of NF-κB. Here for the first time, we assessed the antiangiogenic activity of PR5-LL-CM01 in ocular cells. Immunostaining of human nvAMD sections revealed that PRMT5 is highly expressed in the retinal pigment epithelium (RPE)/choroid where neovascularization occurs, while mouse eyes with laser induced choroidal neovascularization (L-CNV) showed PRMT5 is overexpressed in the retinal ganglion cell layer and in the RPE/choroid. Importantly, inhibition of PRMT5 by PR5-LL-CM01 or shRNA knockdown of PRMT5 in human retinal endothelial cells (HRECs) and induced pluripotent stem cell (iPSC)-derived choroidal endothelial cells (iCEC2) reduced NF-κB activity and the expression of its target genes, such as tumor necrosis factor α (TNF-α) and VEGF-A. In addition to inhibiting angiogenic properties of proliferation and tube formation, PR5-LL-CM01 blocked cell cycle progression at G1/S-phase in a dose-dependent manner in these cells. Thus, we provide the first evidence that inhibition of PRMT5 impedes angiogenesis in ocular endothelial cells, suggesting PRMT5 as a potential therapeutic target to ameliorate ocular neovascularization.

Effect of low and passive flow on OVD thermal properties during phacoemulsification.

OBJECTIVE: To study the thermal properties and response magnitude of a forced-infusion phacoemulsification machine on 4 ophthalmic viscosurgical devices (OVDs). DESIGN: Experimental study. METHODS: A phacoemulsification tip, thermocouple, and gauge were placed into an artificial anterior chamber with balanced saline solution (BSS) or approximately 0.1 mL of OVD. Once the thermocouple measured a consistent temperature, the pedal was engaged for 60 seconds; then the tip was removed. The machine was cooled for 5 minutes and flushed with BSS to return to baseline. This was repeated 10 times for each OVD. The research consisted of 2 scenarios: vacuum-blocked flow rate and low aspiration flow rate. RESULTS: All OVDs showed greater temperature changes than BSS. In the vacuum-blocked scenario, these increases were statistically significant. The medium viscosity dispersive OVD (DiscoVisc) reached temperatures exceeding 60°C. In the low-flow scenario, HEALON5 and DisCoVisc were significantly different at 5 seconds and only HEALON5 at 10 seconds. No temperature increases over BSS were greater than 1.0°C. CONCLUSIONS: The dispersive, cohesive, and viscoadaptive OVDs demonstrated higher temperature changes than BSS but did not reach the threshold for corneal incision contracture. The study team verified the need for at least a minimal flow rate before ultrasound, which is especially evident in the first 10 seconds, because a flow rate of only 20 mL/minute mitigated OVD-related thermal effects. Understanding thermal responses enables corneal incision contracture risk reduction.

An improved method for murine laser-induced choroidal neovascularization lesion quantification from optical coherence tomography images.

Laser-induced choroidal neovascularization (L-CNV) in murine models is a standard method for assessing therapies, genetics, and mechanisms relevant to the blinding eye disease neovascular or "wet" age-related macular degeneration. The ex vivo evaluation of these lesions involves confocal microscopy analysis. In vivo evaluation via optical coherence tomography (OCT) has previously been established and allows longitudinal assessment of lesion development. However, to produce robust data, evaluation of many lesions may be required, which can be a slow, arduous process. A prior, manual method for quantifying these lesions as ellipsoids from orthogonal OCT images was effective but time consuming. We therefore developed an OCT lesion quantification that is simplified, streamlined, and less time-consuming.

Does a cannibal feeding strategy impart differential metabolic performance in young burbot (Lota lota maculosa)?

The practice of mitigating cannibalism in aquaculture is an important focus for hatcheries seeking to maximize yield and has been maintained in hatcheries focusing on wild stock restoration. We hypothesize, however, that a cannibal feeding strategy may confer performance advantages over a non-cannibal feeding strategy and that perhaps cannibal size grading may not be optimal for hatcheries focusing on conservation goals. This study examined metabolic performance differences between cannibal and non-cannibal burbot, Lota lota maculosa, at the Kootenai Tribe of Idaho Twin Rivers Hatchery in Moyie Springs, ID, USA. After habitat alteration led to functional extinction of burbot in the region, the Twin Rivers Hatchery has played a leading role in the reestablishment of burbot in the Kootenai River, ID, and British Columbia. We examined morphometric data (weight, length and condition factor), whole animal resting metabolic rate and the enzyme activity of lactate dehydrogenase, citrate synthase and 3-hydroxyacyl-CoA dehydrogenase to describe the baseline metabolic performance of cannibal and non-cannibal burbot. Taken together, our results demonstrated significant differences in the metabolic strategies of cannibal vs. non-cannibal burbot, where cannibals relied more heavily on carbohydrate metabolism and non-cannibals relied more heavily on glycolytic and lipid metabolism. This study demonstrates the need to reevaluate the traditional practice of removing cannibal fish in conservation hatcheries, as it may not be the ideal strategy of raising the most robust individuals for release. When natural habitat conditions cannot be restored due to permanent habitat alteration, prioritizing release of higher performing individuals could help achieve conservation goals.

Persistence of DNA in carcasses, slime and avian feces may affect interpretation of environmental DNA data.

The prevention of non-indigenous aquatic invasive species spreading into new areas is a goal of many resource managers. New techniques have been developed to survey for species that are difficult to capture with conventional gears that involve the detection of their DNA in water samples (eDNA). This technique is currently used to track the invasion of bigheaded carps (silver carp and bighead carp; Hypophthalmichthys molitrix and H. nobilis) in the Chicago Area Waterway System and Upper Mississippi River. In both systems DNA has been detected from silver carp without the capture of a live fish, which has led to some uncertainty about the source of the DNA. The potential contribution to eDNA by vectors and fomites has not been explored. Because barges move from areas with a high abundance of bigheaded carps to areas monitored for the potential presence of silver carp, we used juvenile silver carp to simulate the barge transport of dead bigheaded carp carcasses, slime residue, and predator feces to determine the potential of these sources to supply DNA to uninhabited waters where it could be detected and misinterpreted as indicative of the presence of live bigheaded carp. Our results indicate that all three vectors are feasible sources of detectable eDNA for at least one month after their deposition. This suggests that current monitoring programs must consider alternative vectors of DNA in the environment and consider alternative strategies to minimize the detection of DNA not directly released from live bigheaded carps.