Anti-vascular endothelial growth factor (anti-VEGF) proteins are the gold-standard treatment for posterior eye segment proliferative vascular diseases such as Age-Related Macular Degeneration (AMD) and Diabetic Retinopathy (DR). However, the standard of care requires inconvenient monthly intravitreal injections. This underlies an unmet clinical need to develop alternative solutions for sustained delivery of biologics. In this paper, we demonstrated that anti-VEGFs can be encapsulated by a simple mild process into our polyurethane thermogel depots. By changing the hydrophilic–hydrophobic balance in the copolymer, anti-VEGF release rates can be modulated. The antibody in the thermogel partitions into protein domains which vary in size corresponding to the hydrophilicity balance of the polymer. Anti-VEGFs can be released in a relatively linear manner from the thermogel for up to 40 days in vitro. The encapsulated anti-VEGFs demonstrate anti-angiogenic bioactivity by inhibiting vessel outgrowth in rat ex vivo choroidal explants, and reducing vascular leakage in a VEGF-driven neovascularization rabbit model. In conclusion, we show that these thermogels can be tuned in terms of hydrophilicity and used for sustained delivery of bioactive anti-VEGFs. Physically cross-linked polyurethane thermoresponsive hydrogels could be a promising platform for sustained delivery of biologically active therapeutic proteins.

Diabetic retinopathy (DR) is an ocular complication of diabetes mellitus (DM). International Diabetic Federations (IDF) estimates up to 629 million people with DM by the year 2045 worldwide. Nearly 50% of DM patients will show evidence of diabetic-related eye problems. Therapeutic interventions for DR are limited and mostly involve surgical intervention at the late-stages of the disease. The lack of early-stage diagnostic tools and therapies, especially in DR, demands a better understanding of the biological processes involved in the etiology of disease progression. The recent surge in literature associated with NOD-like receptors (NLRs) has gained massive attraction due to their involvement in mediating the innate immune response and perpetuating inflammatory pathways, a central phenomenon found in the pathogenesis of ocular diseases including DR. The NLR family of receptors are expressed in different eye tissues during pathological conditions suggesting their potential roles in dry eye, ocular infection, retinal ischemia, cataract, glaucoma, age-related macular degeneration (AMD), diabetic macular edema (DME) and DR. Our group is interested in studying the critical early components involved in the immune cell infiltration and inflammatory pathways involved in the progression of DR. Recently, we reported that NLRP3 inflammasome might play a pivotal role in the pathogenesis of DR. This comprehensive review summarizes the findings of NLRs expression in the ocular tissues with special emphasis on its presence in the retinal microglia and DR pathogenesis.

Bacterial trapping using nanonets is a ubiquitous immune defense mechanism against infectious microbes. These nanonets can entrap microbial cells, effectively arresting their dissemination and rendering them more vulnerable to locally secreted microbicides. Inspired by this evolutionarily conserved anti‐infective strategy, a series of 15 to 16 residue‐long synthetic β‐hairpin peptides is herein constructed with the ability to self‐assemble into nanonets in response to the presence of bacteria, enabling spatiotemporal control over microbial killing. Using amyloid‐specific K114 assay and confocal microscopy, the membrane components lipoteichoic acid and lipopolysaccharide are shown to play a major role in determining the amyloid‐nucleating capacity as triggered by Gram‐positive and Gram‐negative bacteria respectively. These nanonets displayed both trapping and killing functionalities, hence offering a direct improvement from the trap‐only biomimetics in literature. By substituting a single turn residue of the non‐amyloidogenic BTT1 peptide, the nanonet‐forming BTT1‐3A analog is produced with comparable antimicrobial potency. With the same sequence manipulation approach, BTT2‐4A analog modified from BTT2 peptide showed improved antimicrobial potency against colistin‐resistant clinical isolates. The peptide nanonets also demonstrated robust stability against proteolytic degradation, and promising in vivo efficacy and biosafety profile. Overall, these bacteria‐responsive peptide nanonets are promising clinical anti‐infective alternatives for circumventing antibiotic resistance.

Transplantation of stem cell–derived retinal pigment epithelial (RPE) cells is considered a viable therapeutic option for age-related macular degeneration (AMD). Several landmark Phase I/II clinical trials have demonstrated safety and tolerability of RPE transplants in AMD patients, albeit with limited efficacy. Currently, there is limited understanding of how the recipient retina regulates the survival, maturation, and fate specification of transplanted RPE cells. To address this, we transplanted stem cell–derived RPE into the subretinal space of immunocompetent rabbits for 1 mo and conducted single-cell RNA sequencing analyses on the explanted RPE monolayers, compared to their age-matched in vitro counterparts. We observed an unequivocal retention of RPE identity, and a trajectory-inferred survival of all in vitro RPE populations after transplantation. Furthermore, there was a unidirectional maturation toward the native adult human RPE state in all transplanted RPE, regardless of stem cell resource. Gene regulatory network analysis suggests that tripartite transcription factors ( FOS , JUND , and MAFF ) may be specifically activated in posttransplanted RPE cells, to regulate canonical RPE signature gene expression crucial for supporting host photoreceptor function, and to regulate prosurvival genes required for transplanted RPE’s adaptation to the host subretinal microenvironment. These findings shed insights into the transcriptional landscape of RPE cells after subretinal transplantation, with important implications for cell-based therapy for AMD.

Summary: Myopia is a huge public health problem worldwide, reaching the highest incidence in Asia. Identification of susceptible genes is crucial for understanding the biological basis of myopia. In this paper, we have identified and characterized a functional myopia-associated gene using a specific mouse-knockout model. Mice lacking the muscarinic cholinergic receptor gene (M2; also known as Chrm2) were less susceptible to lens-induced myopia compared with wild-type mice, which showed significantly increased axial length and vitreous chamber depth when undergoing experimental induction of myopia. The key findings of this present study are that the sclera of M2 mutant mice has higher expression of collagen type I and lower expression of collagen type V than do wild-type mice and mice that are mutant for other muscarinic subtypes, and, therefore, M2 mutant mice were resistant to the development of experimental myopia. Pharmacological blockade of M2 muscarinic receptor proteins retarded myopia progression in the mouse. These results suggest for the first time a role of M2 in growth-related changes in extracellular matrix genes during myopia development in a mammalian model. M2 receptor antagonists might thus provide a targeted therapeutic approach to the management of this refractive error.

To describe patterns of reperfusion in the superficial vascular plexus (SVP), deep capillary plexus (DCP) and choriocapillaris (CC) as detected on optical coherence tomography (OCTA) in cynomogulus macaque monkey model following increase in intraocular pressure by an intravitreal injection. Animal imaging study. Two cynomogulus macaque monkeys. A 100 µL intravitreal injection (IVI) of saline was given in one eye of each monkey. Serial OCTA using a Zeiss Plex Elite 9000 was used to evaluate reperfusion patterns within the SCP, DCP, and CC. OCTA evidence of perfusion. Pulsation of the central retinal artery was detected after the intraocular pressure was elevated to 98 and ≥ 99 mmHg from IVI. Episodic flow within the SVP arterioles and venules and poor visualization of flow in capillaries was noted during the initial phase of elevated pressure. As the pressure declined, the flow signal within the DCP appeared initially as dots, which progressed laterally to loops which form capillary vortex configuration. Recovery of flow within the SVP and CC appeared sooner than in the DCP. At 40 min after the injection, well after the intraocular pressure normalized, the retinal and choriocapillaris vascular perfusion showed focal defects in every layer. Compared with pre-injection images, vessel density in the DCP was 68.8% and 78.6% of baseline in monkey 1 and monkey 2, respectively. In contrast vessel density in the SVP recovered to 84.2% and 88.9% of baseline. Increases in intraocular pressure from IVI have the potential to affect every layer of blood flow in the fundus. After nominal return of intraocular pressure, focal defects in flow persisted, which may result in longer term damage to the retina.