Advances in retinal pigment epithelial cell transplantation for retinal degenerative diseases.

Retinal degenerative diseases are a leading cause of vision loss and blindness globally, impacting millions. These diseases result from progressive damage to retinal pigment epithelial (RPE) cells for which no curative or palliative treatments exist. Cell therapy, particularly RPE transplantation, has emerged as a promising strategy for vision restoration. This review provides a comprehensive overview of the recent advancements in clinical trials related to RPE transplantation. We discuss scaffold-free and scaffold-based approaches, including RPE cell suspensions and pre-organized RPE monolayers on biomaterial scaffolds. Key considerations, such as the form and preparation of RPE implants, delivery devices, strategies, and biodegradability of scaffolds, are examined. The article also explores the challenges and opportunities in RPE scaffold development, emphasising the crucial need for functional integration, immunomodulation, and long-term biocompatibility to ensure therapeutic efficacy. We also highlight ongoing efforts to optimise RPE transplantation methods and their potential to address retinal degenerative diseases.

Characterization of drusen formation in a primary porcine tissue culture model of dry AMD.

Age-related macular degeneration (AMD) affects millions of individuals worldwide and is a leading cause of blindness in the elderly. In dry AMD, lipoproteinaceous deposits called drusen accumulate between the retinal pigment epithelium (RPE) and Bruch's membrane, leading to impairment of oxygen and nutrient trafficking to the neural retina, and degeneration of the overlying photoreceptor cells. Owing to key differences in human and animal ocular anatomy and the slowly progressing nature of the disease, AMD is not easily modeled in vivo. In this study, we further characterize a "drusen-in-a-dish" primary porcine RPE model system by employing vital lipid staining to monitor sub-RPE deposition over time in monolayers of cells cultured on porous transwell membranes. We demonstrate for the first time using a semi-automated image analysis pipeline that the number and size of sub-RPE deposits increases gradually but significantly over time and confirm that sub-RPE deposits grown in culture immunostain positive for multiple known components found in human drusen. As a result, we propose that drusen-in-a-dish cell culture models represent a high-throughput and cost-scalable alternative to animal models in which to study the pathobiology of drusen accumulation and may serve as useful tools for screening novel therapeutics aimed at treating dry AMD.

Atypical presentation of type 1 neovascularization with aneurysmal dilations in a young female.

Type 1 Neovascularization with Aneurysmal Dilations (N1a), is a retinal disorder characterized by choroidal vascular abnormalities. Clinically, it is characterized by an exudative maculopathy with multiple recurrent serosanguineous pigment epithelial detachments. This disease is more frequent in women aged 55-65 years. However, we present an exceptional case of N1a in a 26-year-old woman, who responded favorably to Aflibercept. To our knowledge, this is the first reported case of a young female patient under 30 with N1a. The patient has responded very favourably to anti-VEGF therapy with three intravitreal injections of Aflibercept. This being the reason for we provide an update on anti-VEGF therapeutic options for N1a.

Human iPSC-based disease modeling studies identify a common mechanistic defect and potential therapies for AMD and related macular dystrophies.

Age-related macular degeneration (AMD) and related macular dystrophies (MDs) primarily affect the retinal pigment epithelium (RPE) in the eye. A hallmark of AMD/MDs that drives later-stage pathologies is drusen. Drusen are sub-RPE lipid-protein-rich extracellular deposits, but how drusen forms and accumulates is not known. We utilized human induced pluripotent stem cell (iPSC)-derived RPE from patients with AMD and three distinct MDs to demonstrate that reduced activity of RPE-secreted matrix metalloproteinase 2 (MMP2) contributes to drusen in multiple maculopathies in a genotype-agnostic manner by instigating sterile inflammation and impaired lipid homeostasis via damage-associated molecular pattern molecule (DAMP)-mediated activation of receptor for advanced glycation end-products (RAGE) and increased secretory phospholipase 2-IIA (sPLA2-IIA) levels. Therapeutically, RPE-specific MMP2 supplementation, RAGE-antagonistic peptide, and a small molecule inhibitor of sPLA2-IIA ameliorated drusen accumulation in AMD/MD iPSC-RPE. Ultimately, this study defines a causal role of the MMP2-DAMP-RAGE-sPLA2-IIA axis in AMD/MDs.

Preparation and characterization of novel natural pigment-indicating film: Application in kiwifruit freshness monitoring.

The marketability of natural pigment-based indicator films is impeded by their weaker color rendering and stability compared with synthetic pigments. Here, we developed novel colorimetric indicators by blending polyvinyl alcohol (PVA) with carboxymethyl cellulose (CMC) and combining alizarin and curcumin. Compared with the individual materials, the PVA and CMC composite films demonstrated superior thermal stability and water resistance. The manufacturing process of these colorimetric indicators was optimized using response surface methodology. The optimum conditions were as follows: PVA at 3.92 g/100 mL; plate pour amount, 48.6 mL; pigment content, 5.8 g/100 mL; pigment ratio, 0.76. The optimized film showed a robust response to CO2 (a color difference of 65.06 ± 2.43). The color difference of the optimized film improved by 98.5 % and 16.86 % for kiwifruit stored at room and low temperatures, respectively. This substantial color change aids in identifying the optimal consumption window for kiwifruit, boosting indicator precision and kiwifruit freshness accuracy.

First description of leucism in the deep-sea angular rough shark (Oxynotus centrina) and the first documented pigment disorder in family Oxynotidae Gill, 1912.

The capture of a rare, critically endangered adult angular rough shark, Oxynotus centrina (Linnaeus, 1758), with abnormal coloration is reported in this paper. The shark exhibited a partial reduction in pigmentation, resulting in an overall pale appearance with white-greyish patches. Since the retinal pigmentation appeared normal, the shark was considered leucistic. This represents the first documented case of leucism in this species and the first colour disorder reported in the family Oxynotidae Gill, 1912. Despite the atypical appearance, the physical health of the shark seemed unaffected, supporting the notion that pigment disorders in deep-sea sharks do not inherently impair survival and growth. Full morphometric characteristics are presented and compared with those of a normal individual of the same sex caught in the same area, showing no differences.

AKT2-mediated lysosomal dysfunction promotes secretory autophagy in retinal pigment epithelium (RPE) cells.

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly, with the non-neovascular or atrophic form being the most common. Current treatment options are limited, emphasizing the urgent need for new therapeutic strategies. Our key finding is that increased levels of AKT2 in the RPE cells impair lysosomal function and trigger secretory autophagy; a non-canonical macroautophagy/autophagy pathway where cellular materials are released via the plasma membrane rather than being degraded by lysosomes. We showed that this process involves a protein complex, AKT2-SYTL1-TRIM16-SNAP23, releasing factors contributing to drusen biogenesis, a clinical hallmark of AMD development. Importantly, SIRT5 can inhibit this pathway, potentially offering a protective effect. Understanding mechanisms by which this non-canonical autophagy pathway promotes extracellular waste accumulation could provide new insights into drusen biogenesis. Future therapies for atrophic AMD could focus on regulating secretory autophagy or manipulating proteins involved in this process.

Choroidal melanocyte secretome from cultured cells and tissue-engineered choroid models exposed to acute or chronic oxidative stress.

The choroid, located between the retina and the sclera, is a vascularized and pigmented connective tissue, playing a crucial role in providing oxygen and nutrients to the outer layers of the retina, and in absorbing excessive light. How choroidal melanocytes (CMs) participate in tissue homeostasis through paracrine signaling with neighboring cells is poorly understood. In this study, using two-dimensional and three-dimensional models, we aimed to identify proteins secreted by CMs under different oxidative stress conditions. To do so, CMs, choroidal fibroblasts (CFs), and retinal pigment epithelial (RPE) cells were isolated from native human RPE/choroidal tissues and expanded. RNA was isolated and processed for gene profiling analysis. The self-assembly approach of tissue engineering was used to form 3D stromal substitutes, and RPE cells and/or CMs were added to produce 3D models with different cell combinations. The medium conditioned by cells in 2D and 3D cultures was collected in a non-stressed condition and following acute or chronic oxidative stress exposures, then proteome and ELISA analyses were performed to identify cytokines secreted majorly by CMs. RNA analysis revealed 15 secretome-related transcripts that were more abundantly expressed in CMs compared to the other 2 cell types, including serpin family F member 1 (SERPINF1) (coding for pigment epithelium-derived factor; PEDF) and secreted phosphoprotein 1 (SPP1) (coding for osteopontin). At the protein level, the expression of osteopontin and PEDF was higher in CMs of different age groups compared to CFs and RPE cells. In the 3D models containing CMs, cytokine arrays also identified macrophage inflammatory protein (MIP)-1α/MIP-1ß in non-stressed, MIP-1α/MIP-1ß, interleukin (IL)-24, and angiogenin following an acute oxidative stress, and macrophage migration inhibitory factor (MIF), granulocyte-colony stimulating factor (G-CSF), intercellular adhesion molecule-1 (ICAM-1), and IL-1α following a chronic oxidative stress. This study identifies for the first time trophic factors secreted by CMs that could influence neighboring cells through paracrine signaling. Of those, PEDF and osteopontin are antioxidative proteins that are known to attenuate oxidative stress damage. Identifying factors that can help manage oxidative stress in the posterior segment of the eye may lead to promising treatments for retinal diseases.

Reducing disparities in the care of atopic dermatitis.

Atopic Dermatitis (AD) is associated with a number of published disparities, including those related to self-identified racial/ethnic populations. Black/African American populations in the United States experience greater AD prevalence, severity, and persistence compared to other demographic groups, such as those who self-identify as White. There is consistent evidence that healthcare, environmental, and socioeconomic factors affect the prevalence, severity, and/or persistence of AD. Additionally, because of institutional and systemic racism, these same risk factors are more prevalent in racial and ethnic minority populations. Herein, we review the underlying causes of racial/ethnic disparities in AD and potential strategies to improve AD diagnosis and disease control.

Multiple Evanescent White Dot Syndrome (MEWDS) Secondary to Acute Retinal Pigment Epitheliitis: Possible Atypical Presentation of MEWDS?

PURPOSE: To report a case of possible multiple evanescent white dot syndrome secondary (MEWDS) to acute retinal pigment epitheliitis (ARPE). METHODS: Case report. RESULTS: A 16-year-old female presented to the ophthalmology emergency department with a 5-day history of blurred vision in the left eye (OS). Initial examination revealed a visual acuity (VA) of 89 letters on the Early Treatment Diabetic Retinopathy Study (ETDRS)(-0.08 logMAR) chart in the right eye (OD) and 53 letters(0.64 logMAR) in the OS. Anterior segment biomicroscopy was normal, with no evidence of inflammation in the anterior chamber. Evaluation of the posterior pole revealed an alteration in the retinal pigment epithelium (RPE) in the OS. Optical coherence tomography (OCT) at the macular level showed disruption at the external limiting membrane (ELM), ellipsoid zone (EZ), interdigitation zone (IZ), and the RPE-Bruch's membrane (RPE-Bm) complex. Fundus autofluorescence (FAF) demonstrated hypofluorescent areas in the peripapillary region. No treatment was indicated. After two weeks, there was an improvement in VA, with 90 ETDRS letters(-0.1 logMAR) in the OD and 85 letters(0.0 logMAR) in the OS, as well as improvement in the OCT at the level of the ELM and EZ. However, a marked increase in white spots was observed throughout the posterior pole. By 5-months post-onset, a complete resolution of retinal alterations was observed in both OCT and FAF. CONCLUSION: ARPE and MEWDS exhibit overlapping clinical features, which can sometimes complicate differentiation. This case is consistent with MEWDS secondary to ARPE, although an atypical presentation of MEWDS cannot be ruled out.

Chlorophyll and Carotenoid Metabolism Varies with Growth Temperatures among Tea Genotypes with Different Leaf Colors in Camellia sinensis.

The phenotype of albino tea plants (ATPs) is significantly influenced by temperature regimes and light conditions, which alter certain components of the tea leaves leading to corresponding phenotypic changes. However, the regulatory mechanism of temperature-dependent changes in photosynthetic pigment contents and the resultant leaf colors remain unclear. Here, we examined the chloroplast microstructure, shoot phenotype, photosynthetic pigment content, and the expression of pigment synthesis-related genes in three tea genotypes with different leaf colors under different temperature conditions. The electron microscopy results revealed that all varieties experienced the most severe chloroplast damage at 15 °C, particularly in albino cultivar Baiye 1 (BY), where chloroplast basal lamellae were loosely arranged, and some chloroplasts were even empty. In contrast, the chloroplast basal lamellae at 35 °C and 25 °C were neatly arranged and well-developed, outperforming those observed at 20 °C and 15 °C. Chlorophyll and carotenoid measurements revealed a significant reduction in chlorophyll content under low temperature treatment, peaking at ambient temperature followed by high temperatures. Interestingly, BY showed remarkable tolerance to high temperatures, maintaining relatively high chlorophyll content, indicating its sensitivity primarily to low temperatures. Furthermore, the trends in gene expression related to chlorophyll and carotenoid metabolism were largely consistent with the pigment content. Correlation analysis identified key genes responsible for temperature-induced changes in these pigments, suggesting that changes in their expression likely contribute to temperature-dependent leaf color variations.

Molybdenum doping leads to faster photo-dissolution of commercial molybdate red pigment than chrome yellow pigment under sunlight irradiation.

The photo-dissolution of lead chromate pigments poses specific environmental hazards. In this study, we report that doping molybdenum in lead chromate pigments, resulting in commonly known molybdate red pigment, increases the risk of heavy metal leaching when exposed to light. Commercial molybdate red pigments undergo photo-dissolution when exposed to simulated sunlight and exhibit lower photostability compared to lead chromate pigments such as chrome yellow. After 24 hours of irradiation, the leaching rates of toxic lead and chromium from molybdate red pigments were 2.98 and 3.70 times higher, respectively, than those from chrome yellow pigments. The primary factor leading to decreased pigment photostability is the activation of pigment semiconductors facilitated by molybdenum doping. Molybdate red pigments exhibit a broader light absorption spectrum and more efficient separation and transfer of photogenerated charge carriers than chrome yellow pigments, boosting the photochemical activity. To the best of our knowledge, this is the first study to illustrate the doping effect on the photostability of commercial inorganic pigments and the consequent heavy metal leaching. Our results suggest that Mo doping reduces the photostability of lead chromate pigments, highlighting the potential elevated environmental risks associated with complex inorganic pigments.

Innovative approaches to harnessing natural pigments from food waste and by-products for eco-friendly food coloring.

With unprecedented growth in the world population, the demand for food has risen drastically leading to increased agricultural production. One promising avenue is recovery of value-added pigments from food waste which has been gaining global attention. This review focuses on sustainable strategies for extracting pigments, examining the factors that influence extraction, their applications, and consumer acceptability. The significant findings of the study state the efficiency of pigment extraction through innovative extraction techniques rather than following conventional methods that are time-consuming, and unsustainable. In addition to their vibrant colors, these pigments provide functional benefits such as antioxidant properties, extended shelf life and improved food quality. Societal acceptance of pigments derived from food waste is positively driven by environmental awareness and sustainability. The study concludes by highlighting the stability challenges associated with various natural pigments, emphasizing the need for tailored stabilization methods to ensure long-term stability and effective utilization in food matrices.

Predictive factors for Submacular Hemorrhage in Age-related Macular Degeneration: A Retrospective Study.

Purpose: Little is known about the major risk factors for submacular hemorrhage (SMH). This study aimed to evaluate the factors associated with SMH in patients with neovascular age-related macular degeneration (nAMD) and polypoidal choroidal vasculopathy (PCV) receiving three consecutive loading doses of intravitreal aflibercept or ranibizumab injections. Methods: This retrospective cross-sectional study included 48 patients diagnosed with wAMD and PCV who completed three loading doses under a treat-and-extend regimen. Patients were divided into the SMH group (n=24) and the non-SMH group (age- and sex-matched without SMH). Intravitreal injections, agents, and optical coherence tomography (OCT) features were compared. Results: In the SMH group, SMH occurred approximately 3.29 years after post-nAMD diagnosis. The non-SMH group received more intravitreal injections of aflibercept and brolucizumab during the follow-up period after the initial loading phase. The SMH group exhibited a higher prevalence of serous/hemorrhagic pigment epithelial detachments (PEDs) at the last visit before SMH occurrence compared to the non-SMH group. Patients with a PED increase in the past two visits showed a higher tendency in the SMH group. No other OCT features significantly correlated with SMH development. Conclusions: The presence of serous/hemorrhagic PEDs may indicate a higher risk of SMH, and eyes with these features should be closely monitored to prevent sudden and devastating visual loss caused by SMH.

Prominin-1 null Xenopus laevis develop subretinal drusenoid-like deposits, cone-rod dystrophy, and RPE atrophy.

PROMININ-1 (PROM1) mutations are associated with inherited, non-syndromic vision loss. We used CRISPR/Cas9 to induce prom1-null mutations in Xenopus laevis and then tracked retinal disease progression from the ages of 6 weeks to 3 years old. Prom1-null associated retinal degeneration in frogs is age-dependent and involves RPE dysfunction preceding photoreceptor degeneration. Before photoreceptor degeneration occurs, aging prom1-null frogs develop increasing size and numbers of cellular debris deposits in the subretinal space and outer segment layer, which resemble subretinal drusenoid deposits (SDD) in their location, histology, and representation in color fundus photography and optical coherence tomography (OCT). Evidence for an RPE origin of these deposits includes infiltration of pigment granules into the deposits, thinning of RPE as measured by OCT, and RPE disorganization as measured by histology and OCT. The appearance and accumulation of SDD-like deposits and RPE thinning and disorganization in our animal model suggests an underlying disease mechanism for prom1-null mediated blindness of death and dysfunction of the RPE preceding photoreceptor degeneration, instead of direct effects upon photoreceptor outer segment morphogenesis, as was previously hypothesized.

An in vitro cell model for exploring inflammatory and amyloidogenic events in alkaptonuria.

Alkaptonuria (AKU) is a progressive systemic inherited metabolic disorder primarily affecting the osteoarticular system, characterized by the degeneration of cartilage induced by ochronosis, ultimately leading to early osteoarthritis (OA). However, investigating AKU pathology in human chondrocytes, which is crucial for understanding the disease, encounters challenges due to limited availability and donor variability. To overcome this obstacle, an in vitro model has been established using homogentisic acid (HGA) to simulate AKU conditions. This model employed immortalized C20/A4 human chondrocytes and serves as a dependable platform for studying AKU pathogenesis. Significantly, the model demonstrates the accumulation of ochronotic pigment in HGA-treated cells, consistent with findings from previous studies. Furthermore, investigations into inflammatory processes during HGA exposure revealed notable oxidative stress, as indicated by elevated levels of reactive oxygen species and lipid peroxidation. Additionally, the model demonstrated HGA-induced inflammatory responses, evidenced by increased production of nitric oxide, overexpression of inducible nitric oxide synthase, and cyclooxygenase-2. These findings underscore the model's utility in studying inflammation associated with AKU. Moreover, analysis of serum amyloid A and serum amyloid P proteins revealed a potential interaction, corroborating evidence of amyloid fibril formation. This hypothesis was further supported by Congo red staining, which showed fibril formation exclusively in HGA-treated cells. Overall, the C20/A4 cell model provided valuable insights into AKU pathogenesis, emphasizing its potential for facilitating drug development and therapeutic interventions.

PRN: progressive reasoning network and its image completion applications.

Ancient murals embody profound historical, cultural, scientific, and artistic values, yet many are afflicted with challenges such as pigment shedding or missing parts. While deep learning-based completion techniques have yielded remarkable results in restoring natural images, their application to damaged murals has been unsatisfactory due to data shifts and limited modeling efficacy. This paper proposes a novel progressive reasoning network designed specifically for mural image completion, inspired by the mural painting process. The proposed network comprises three key modules: a luminance reasoning module, a sketch reasoning module, and a color fusion module. The first two modules are based on the double-codec framework, designed to infer missing areas' luminance and sketch information. The final module then utilizes a paired-associate learning approach to reconstruct the color image. This network utilizes two parallel, complementary pathways to estimate the luminance and sketch maps of a damaged mural. Subsequently, these two maps are combined to synthesize a complete color image. Experimental results indicate that the proposed network excels in restoring clearer structures and more vivid colors, surpassing current state-of-the-art methods in both quantitative and qualitative assessments for repairing damaged images. Our code and results will be publicly accessible at https://github.com/albestobe/PRN .

A Case of Neuroleptic Malignant Syndrome-Prompted Myoglobin Cast Nephropathy.

Myoglobin cast nephropathy is a sequel of rhabdomyolysis, and is characterized by the release of free myoglobin in the circulation, direct proximal convoluted tubule injury, and obstruction by myoglobin cast in distal tubules. We report an interesting case of myoglobin cast nephropathy in a patient who was on neuroleptic drugs and who presented with neuroleptic malignant syndrome and acute kidney injury.

CYLD Maintains Retinal Homeostasis by Deubiquitinating ENKD1 and Promoting the Phagocytosis of Photoreceptor Outer Segments.

Phagocytosis of shed photoreceptor outer segments by the retinal pigment epithelium (RPE) is essential for retinal homeostasis. Dysregulation of the phagocytotic process is associated with irreversible retinal degenerative diseases. However, the molecular mechanisms underlying the phagocytic activity of RPE cells remain elusive. In an effort to uncover proteins orchestrating retinal function, the cylindromatosis (CYLD) deubiquitinase is identified as a critical regulator of photoreceptor outer segment phagocytosis. CYLD-deficient mice exhibit abnormal retinal structure and function. Mechanistically, CYLD interacts with enkurin domain containing protein 1 (ENKD1) and deubiquitinates ENKD1 at lysine residues K141 and K242. Deubiquitinated ENKD1 interacts with Ezrin, a membrane-cytoskeleton linker, and stimulates the microvillar localization of Ezrin, which is essential for the phagocytic activity of RPE cells. These findings thus reveal a crucial role for the CYLD-ENKD1-Ezrin axis in regulating retinal homeostasis and may have important implications for the prevention and treatment of retinal degenerative diseases.