Comparison of Retinal Metabolic Activity and Structural Development between rd10 Mice and Normal Mice Using Multiphoton Fluorescence Lifetime Imaging Microscopy.

Fluorescence lifetime imaging microscopy (FLIM) is a technique that analyzes the metabolic state of tissues based on the spatial distribution of fluorescence lifetimes of certain interacting molecules. We used multiphoton FLIM to study the metabolic state of developing C57BL6/J and rd10 retinas based on the fluorescence lifetimes of free versus bound nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate (NAD(P)H), with free NAD(P)H percentages suggesting increased glycolysis and bound NAD(P)H percentages indicating oxidative phosphorylation. The mice were sacrificed and enucleated at various time points throughout their first 3 months of life. The isolated eyecups were fixed, sectioned using a polyacrylamide gel embedding technique, and then analyzed with FLIM. The results suggested that in both C57BL6/J mice and rd10 mice, oxidative phosphorylation initially decreased and then increased, plateauing over time. This trend, however, was accelerated in rd10 mice, with its turning point occurring at p10 versus the p30 turning point in C57BL6/J mice. There was also a noticeable difference in oxidative phosphorylation rates between the outer and inner retinas in both strains, with greater oxidative phosphorylation present in the latter. A greater understanding of rd10 and WT metabolic changes during retinal development may provide deeper insights into retinal degeneration and facilitate the development of future treatments.

VISUAL AND ANATOMICAL OUTCOMES AFTER DIABETIC TRACTION AND TRACTION-RHEGMATOGENOUS RETINAL DETACHMENT REPAIR.

PURPOSE: To evaluate visual and anatomical outcomes of diabetic tractional retinal detachment repaired with pars plana vitrectomy. METHODS: Operative records were used to retrospectively identify all patients with tractional retinal detachments secondary to proliferative diabetic retinopathy surgically repaired with pars plana vitrectomy between November 1, 2009, and January 1, 2015 at the LAC + USC (Los Angeles County + University of Southern California) Medical Center. RESULTS: A total of 403 eyes with diabetic tractional retinal detachment in 359 patients were included. Successful reattachment of the retina was achieved in 87.6% of eyes after one surgery and 92.6% of eyes at the final follow-up. Best-corrected visual acuity at the final follow-up improved two or more lines in 56.3% of eyes, was stable in 23.8% of eyes, and decreased two or more lines in 19.9% of eyes. Eyes repaired with 23-gauge and 25-gauge vitrectomy systems had similar success rates as eyes treated with 20-gauge instrumentation (P = 0.73). Eyes receiving silicone oil tamponade had lower single-surgery reattachment rates (77.6% vs. 87.6%; P = 0.013), lower reattachment rates at the final follow-up (85.7% vs. 92.6%; P = 0.048), and higher rates of vision loss (34.7% vs. 19.9%; P < 0.0001) but were more likely to have concurrent rhegmatogenous detachment (47.0% vs. 21.3%; P < 0.0001) and macula involving detachment (74.5% vs. 60.0%; P < 0.0001). CONCLUSION: In this large, single-center retrospective study of patients with advanced diabetic tractional retinal detachment, vitrectomy achieved excellent anatomical outcome and improved or stabilized vision in 80.1% of eyes. Smaller gauge vitrectomy systems were found to have similar outcomes to 20-gauge instrumentation.

Type 3 neovascularization: evolution, association with pigment epithelial detachment, and treatment response as revealed by spectral domain optical coherence tomography.

PURPOSE: To demonstrate the evolution and treatment response of Type 3 neovascularization using spectral domain optical coherence tomography. METHODS: We retrospectively analyzed 40 eyes treated with intravitreal anti-vascular endothelial growth factor therapy for Type 3 neovascularization over a variable follow-up period. RESULTS: In 17 eyes, spectral domain optical coherence tomography captured the development of Type 3 neovascularization from punctate hyperreflective foci that preceded any outer retinal defect. The more mature Type 3 lesions were associated with outer retinal disruption and adjacent cystoid macular edema. In addition, 37 of 40 Type 3 lesions (93%) were associated with an underlying pigment epithelial detachment, of which 26 (70%) were drusenoid, 6 (16%) serous, and 5 (14%) mixed. Type 3 vessels appeared to leak fluid into the pigment epithelial detachment cavity, creating serous pigment epithelial detachments as large as 925 µm in maximal height. Treatment with anti-vascular endothelial growth factor agents led to prompt involution of the lesion and resorption of the intraretinal and subretinal pigment epithelium fluid after one or two injections (median = 1). CONCLUSION: In some eyes with age-related macular degeneration, the earliest sign of Type 3 neovascularization is punctate hyperreflective foci above the external limiting membrane. The mature Type 3 lesions and associated serous pigment epithelial detachments are highly responsive to anti-vascular endothelial growth factor therapy.

Retinal Cell Biology in Health and Disease.

The intricate network of cells and processes that govern retinal health has long been a subject of fascination and intensive study within the scientific community [...].

Comparison of The Results of Sponsored Genetic Testing Panels for Inherited Retinal Diseases.

Background/Objectives: Gene therapy's emergence has made molecular diagnosis for inherited retinal diseases clinically significant. Free genetic testing panels have improved testing access in clinical practice, yet the interpretation of results, especially variants of unknown significance (VUS), remains challenging and requires expertise. This study shares our experience in utilizing sponsored IRD panel tests by Invitae and Blueprint Genetics (BG), reporting their positivity rates, and comparing their reclassification of variants through amendments. Methods: This retrospective study analyzed genetic test reports from patients who underwent testing via Invitae or BG panels. A positive test was determined if there was a pathogenic mutation in an autosomal dominant gene, two pathogenic mutations in an autosomal recessive gene, or a pathogenic mutation in an X-linked gene in a male patient. Results: The testing positivity rates were 34.9% for Invitae (n = 109) and 42.1% for BG (n = 107). Invitae had more pathogenic variants per report (0.87 vs. 0.58 variants, p = 0.0038) and issued more amendments than BG (0.54 vs. 0.03 amendments; p < 0.01). Of the Invitae variant classification changes, 66.2% switched a VUS to benign. In the BG group, 75% of variant reclassifications changed a VUS to pathogenic. As a result of the Invitae amendments, 88% did not change the overall report result. Conclusions: While free-of-charge genetic testing panels offer valuable insights for diagnosing IRD, limitations such as low diagnostic yield and variant classification discrepancies persist between Invitae and BG. VUS should not be considered pathogenic in the clinical decision-making process. Careful interpretation of genetic testing is required.

Visual Cortical Thickness Increases with Prolonged Artificial Vision Restoration.

The Argus II retinal prosthesis restores visual perception to late blind patients. It has been shown that structural changes occur in the brain due to late-onset blindness, including cortical thinning in visual regions of the brain. Following vision restoration, it is not yet known whether these visual regions are reinvigorated and regain a normal cortical thickness or retain the diminished thickness from blindness. We evaluated the cortical thicknesses of ten Argus II Retinal Prostheses patients, ten blind patients, and thirteen sighted participants. The Argus II patients on average had a thicker left Cuneus Cortex and Lateral Occipital Cortex relative to the blind patients. The duration of the Argus II use (time since implant in active users) significantly partially correlated with thicker visual cortical regions in the left hemisphere. Furthermore, in the two case studies (scanned before and after implantation), the patient with longer device use (44.5 months) had an increase in the cortical thickness of visual regions, whereas the shorter-using patient did not (6.5 months). Finally, a third case, scanned at three time points post-implantation, showed an increase in cortical thickness in the Lateral Occipital Cortex between 43.5 and 57 months, which was maintained even after 3 years of disuse (106 months). Overall, the Argus II patients' cortical thickness was on average significantly rejuvenated in two higher visual regions and, patients using the implant for a longer duration had thicker visual regions. This research raises the possibility of structural plasticity reversing visual cortical atrophy in late-blind patients with prolonged vision restoration.

Mycobacterium dormancy and antibiotic tolerance within the retinal pigment epithelium of ocular tuberculosis.

Tuberculosis (TB) is a leading cause of death among infectious diseases worldwide due to latent TB infection, which is the critical step for the successful pathogenic cycle. In this stage, Mycobacterium tuberculosis resides inside the host in a dormant and antibiotic-tolerant state. Latent TB infection can lead to a multisystemic diseases because M. tuberculosis invades virtually all organs, including ocular tissues. Ocular tuberculosis (OTB) occurs when the dormant bacilli within ocular tissues reactivate, originally seeded by hematogenous spread from pulmonary TB. Timely and accurate diagnosis as well as efficient chemotherapies are crucial in preventing poor visual outcomes of OTB patients. Histological evidence suggests that retinal pigment epithelium (RPE) cells play a central role in immune privilege and in the protection from the antibiotic effects, making them an anatomical niche for invading M. tuberculosis . RPE cells exhibit high tolerance to environmental redox stresses, allowing phagocytosed M. tuberculosis bacilli to maintain viability in a dormant state. However, the microbiological and metabolic mechanisms determining the interaction between the RPE intracellular environment and phagocytosed M. tuberculosis are largely unknown. Here, liquid chromatography mass spectrometry (LC-MS) metabolomics was used to illuminate the metabolic state within RPE cells reprogrammed to harbor dormant M. tuberculosis bacilli and enhance the antibiotic tolerance. The results have led to propose a novel therapeutic option to synthetically kill the dormant M. tuberculosis inside the RPE cells by modulating the phenotypic state of M. tuberculosis , thus laying the foundation for a new, innovative regimen for treating OTB. Importance: Understanding the metabolic environment within the retinal pigment epithelium (RPE) cells altered by infection with M. tuberculosis and mycobacterial dormancy is crucial to identify new therapeutic methods to cure OTB. The present study showed that RPE cellular metabolism is altered to foster intracellular M. tuberculosis to enter into the dormant and drug tolerant state, thereby blunting the efficacy of anti-TB chemotherapy. RPE cells serve as an anatomical niche as the cells protect invading bacilli from antibiotic treatment. LC-MS metabolomics of RPE cells after co-treatment with H2O2 and M. tuberculosis infection showed that intracellular environment within RPE cells is enriched with greater level of oxidative stress. The antibiotic tolerance of intracellular M. tuberculosis within RPE cells can be restored by a metabolic manipulation strategy such as co-treatment of antibiotic with the most downstream glycolysis metabolite, phosphoenolpyruvate.

Mycobacterium dormancy and antibiotic tolerance within the retinal pigment epithelium of ocular tuberculosis.

Tuberculosis (TB) is a leading cause of death among infectious diseases worldwide due to latent TB infection, which is the critical step for the successful pathogenic cycle. In this stage, Mycobacterium tuberculosis resides inside the host in a dormant and antibiotic-tolerant state. Latent TB infection can also lead to multisystemic diseases because M. tuberculosis invades virtually all organs, including ocular tissues. Ocular tuberculosis (OTB) occurs when the dormant bacilli within the ocular tissues reactivate, originally seeded by hematogenous spread from pulmonary TB. Histological evidence suggests that retinal pigment epithelium (RPE) cells play a central role in immune privilege and in protection from antibiotic effects, making them an anatomical niche for invading M. tuberculosis. RPE cells exhibit high tolerance to environmental redox stresses, allowing phagocytosed M. tuberculosis bacilli to maintain viability in a dormant state. However, the microbiological and metabolic mechanisms determining the interaction between the RPE intracellular environment and phagocytosed M. tuberculosis are largely unknown. Here, liquid chromatography-mass spectrometry metabolomics were used to illuminate the metabolic state within RPE cells reprogrammed to harbor dormant M. tuberculosis bacilli and enhance antibiotic tolerance. Timely and accurate diagnosis as well as efficient chemotherapies are crucial in preventing the poor visual outcomes of OTB patients. Unfortunately, the efficacy of current methods is highly limited. Thus, the results will lead to propose a novel therapeutic option to synthetically kill the dormant M. tuberculosis inside the RPE cells by modulating the phenotypic state of M. tuberculosis and laying the foundation for a new, innovative regimen for treating OTB. IMPORTANCE: Understanding the metabolic environment within the retinal pigment epithelium (RPE) cells altered by infection with Mycobacterium tuberculosis and mycobacterial dormancy is crucial to identify new therapeutic methods to cure ocular tuberculosis. The present study showed that RPE cellular metabolism is altered to foster intracellular M. tuberculosis to enter into the dormant and drug-tolerant state, thereby blunting the efficacy of anti-tuberculosis chemotherapy. RPE cells serve as an anatomical niche as the cells protect invading bacilli from antibiotic treatment. LC-MS metabolomics of RPE cells after co-treatment with H2O2 and M. tuberculosis infection showed that the intracellular environment within RPE cells is enriched with a greater level of oxidative stress. The antibiotic tolerance of intracellular M. tuberculosis within RPE cells can be restored by a metabolic manipulation strategy such as co-treatment of antibiotic with the most downstream glycolysis metabolite, phosphoenolpyruvate.

Effects of Smoothing and Adaptive Filtering in Multifocal Electroretinography (mfERG).

(1) Background: mfERG testing is used to study the function of cone photoreceptors in the central retina. Various filters including "smoothing" (Smooth) and "adaptive data filtering" (Adapt) are used to simplify raw data. This study will seek to characterize the effect of data modification on raw patient data. (2) Methods: This was a retrospective study of patients with mfERG results at our institution. For each patient, raw mfERG data without filtering, with smooth level 4 modifier applied, and with adapt level 4 applied were collected and compared. (4) Conclusions: In all patients, smoothing and adaptive filter modifiers create statistically significant differences in both P1 latency and P1 amplitude values when compared to raw data. The impacts of these filters demonstrated in this study should impact physicians' decision making when interpreting mfERG results.

Optical coherence tomography in healthy human subjects in the setting of prolonged dark adaptation.

Human studies have established that short periods of dark adaptation can induce outer retinal thinning and various band intensity changes that can be detected with Optical Coherence Tomography (OCT). Similar findings were observed in mice, including a positive correlation between the degree of outer retinal changes and dark adaptation duration. We decided to assess potential retinal structural changes following prolonged dark adaptation in humans. 40 healthy subjects without any ocular diseases participated in this study. For each subject, one eye was covered for dark adaptation for four hours, and the other eye was left uncovered as a control. Before and after the dark adaptation period, both eyes were assessed with OCT. Using the Heidelberg Spectralis system, basic statistical functions, and qualitative and quantitative analysis, we were able to compare retinal layer thicknesses and band intensities between covered (dark adapted) versus uncovered (control) eyes. Prolonged dark adaptation did not induce any significant thickness, volume, or intensity changes in the outer retina or in the inner or overall retina. These observations thus alter our current understanding of the mechanisms underlying dark adaptation's neuroprotective effects in preventing blindness and require further study.