Magnetic Nano-Platform Enhanced iPSC-Derived Trabecular Meshwork Delivery and Tracking Efficiency

iPSC-derived cells stimulate ABCG2+/NES+ endogenous trabecular meshwork cell proliferation and tissue regeneration

A major risk factor for glaucoma, the first leading cause of irreversible blindness worldwide, is the decellularisation of the trabecular meshwork (TM) in the conventional outflow pathway. Stem cell-based therapy, particularly the utilisation of induced pluripotent stem cells (iPSCs), presents an enticing potential for tissue regeneration and intraocular pressure (IOP) maintenance in glaucoma. We have previously observed that differentiated iPSCs can stimulate endogenous cell proliferation in the TM, a pivotal factor in TM regeneration and aqueous humour outflow restoration. In this study, we investigated the response of TM cells in vivo after interacting with iPSC-derived cells and identified two subpopulations responsible for this relatively long-term tissue regeneration: ATP Binding Cassette Subfamily G Member 2 (ABCG2)-positive cells and Nestin (NES)-positive cells. We further uncovered that alterations of these responsive cells are linked to ageing and different glaucoma etiologies, suggesting that ABCG2+ subpopulation decellularization could serve as a potential risk factor for TM decellularization in glaucoma. Taken together, our findings illustrated the proliferative subpopulations in the conventional outflow pathway when stimulated with iPSC-derived cells and defined them as TM precursors, which may be applied to develop novel therapeutic approaches for glaucoma.

Magnetically Steered Cell Therapy For Functional Restoration Of Intraocular Pressure Control In Open-Angle Glaucoma

Trabecular meshwork (TM) cell therapy has been proposed as a next-generation treatment for elevated intraocular pressure (IOP) in glaucoma, the most common cause of irreversible blindness. Using a magnetic cell steering technique with excellent efficiency and tissue-specific targeting, we delivered two types of cells into a mouse model of glaucoma: either human adipose-derived mesenchymal stem cells (hAMSCs) or induced pluripotent cell derivatives (iPSC-TM cells). We observed a 4.5 [3.1, 6.0] mmHg or 27% reduction in intraocular pressure (IOP) for nine months after a single dose of only 1500 magnetically-steered hAMSCs, associated with restoration of function to the conventional outflow pathway, as judged by increased outflow facility and TM cellularity. iPSC-TM cells were also effective, but less so, showing only a 1.9 [0.4, 3.3] mmHg or 13% IOP reduction and increased risk of tumorigenicity. In both cases, injected cells remained detectable in the iridocorneal angle three weeks post-transplantation. Based on the locations of the delivered cells, the mechanism of IOP lowering is most likely paracrine signaling. We conclude that magnetically-steered hAMSC cell therapy has potential for long-term treatment of ocular hypertension in glaucoma.

One Sentence Summary

A novel magnetic cell therapy provided effective intraocular pressure control in a mouse model of glaucoma, motivating future translational studies.

Nanotechnology in Retinal Disease: Current Concepts and Future Directions

The retina is one of the most complex and extraordinary human organs affected by genetic, metabolic, and degenerative diseases, resulting in blindness for ∼1.3 million people in the United States and over 40 million people worldwide. This translates into a huge loss of productivity, especially among younger patients with inherited retinal diseases (IRDs) and diabetic retinopathy. Age-related macular degeneration accounts for 90% of all blindness cases worldwide. The prevalence of this condition is projected to reach over 5 million individuals over the next 3 decades. There are also >20 IRD phenotypes, affecting >2 million people worldwide. Nanobiotechnology uses nanotechnology for biological applications, making use of biological materials either conceptually or directly in the fabrication of new materials. Bionanotechnology, on the other hand, uses molecular biology for the purpose of creating nanostructures (ie, structures with at least 1 dimension <100 nm). Retinal applications of these technologies are developing at a rapid pace. This review includes the most current nanotechnological applications in retinal diagnostics, theranostics, drug delivery, and targeting, including the potential for nonviral vehicles such as liposomes, micelles, and dendrimers, which pose advantages over viral vectors in retinal drug delivery. Furthermore, we discuss current and future applications as surgical adjuncts and in regenerative medicine as they pertain to retinal disease. Structure and function of nanoparticles such as carbon nanotubules, quantum dots, and magnetic nanoparticles, as well as diagnostic technologies such as next-generation DNA sequencing and single-molecule bionanosensing, will also be discussed.

Improved magnetic delivery of cells to the trabecular meshwork in mice

Glaucoma is the leading cause of irreversible blindness worldwide and its most prevalent subtype is primary open angle glaucoma (POAG). One pathological change in POAG is loss of cells in the trabecular meshwork (TM), which is thought to contribute to ocular hypertension and has thus motivated development of cell-based therapies to refunctionalize the TM. TM cell therapy has shown promise in intraocular pressure (IOP) control, but existing cell delivery techniques suffer from poor delivery efficiency. We employed a novel magnetic delivery technique to reduce the unwanted side effects of off-target cell delivery. Mesenchymal stem cells (MSCs) were labeled with superparamagnetic iron oxide nanoparticles (SPIONs) and after intracameral injection were magnetically steered towards the TM using a focused magnetic apparatus ("point magnet"). This technique delivered the cells significantly closer to the TM at higher quantities and with more circumferential uniformity compared to either unlabeled cells or those delivered using a "ring magnet" technique. We conclude that our point magnet cell delivery technique can improve the efficiency of TM cell therapy and in doing so, potentially increase the therapeutic benefits and lower the risk of complications such as tumorigenicity and immunogenicity.

A bibliometric analysis of the application of stem cells in glaucoma research from 1999 to 2022

Background: Glaucoma, a neurodegenerative disease of the retina, is the leading cause of irreversible blindness. Stem cells have therapeutic potential for glaucoma. However, few bibliometric studies have been published in this field. Concerning a visual map, this article aims to characterize the research context, cooperation relationship, hotspots, and trends concerning the application of stem cells in glaucoma research. Methods: Publications focusing on stem cell research and glaucoma were retrieved from the Web of Science Core Collection. VOSviewer, CiteSpace, Microsoft Excel, and Scimago Graphica were used to map the contributions of countries or regions, authors, organizations, and journals. Journal Impact Factor data were obtained from the Web of Science Core Collection. We analyzed the tendencies, hotspots, and knowledge networks using VOSviewer, and CiteSpace. Results: We analyzed 518 articles published from 1999 through 2022. In the first decade, the number of articles in this field increased slowly, and there was a marked acceleration in publication frequency after 2010. The United States, China, and England were the main contributors. Yiqin Du was the most prolific author, and among the top 10 prolific writers, Keith R. Martin's work was cited most frequently. Investigative Ophthalmology and Visual Science, Experimental Eye Research, and Cornea published the most articles in this domain. The three most commonly co-cited journals were Investigative Ophthalmology and Visual Science, Experimental Eye Research, and Proceedings of the National Academy of Sciences of the United States of America. The Central South University, the University of Pittsburgh, and the National Institutes of Health National Eye Institute were highly prolific institutions in this research area. Our keywords analysis with VOSviewer suggested directions of future research and yielded the following recent key themes, extracellular vesicles, exosomes, mitochondria, growth factors, oxidative stress, and ocular diseases. Four co-cited references had a citation burst duration until 2022. Conclusion: With improvements in overall quality of life and demographic transitions toward population aging, research and clinical focus on eye care has increased, with glaucoma as a key area of emphasis. This study added to our understanding of the global landscape and Frontier hotspots in this field.

iPSCs-Based Therapy for Trabecular Meshwork

The trabecular meshwork (TM) of the eye serves as an essential tissue in controlling aqueous humor (AH) outflow and intraocular pressure (IOP) homeostasis. However, dysfunctional TM cells and/or decreased TM cellularity is become a critical pathogenic cause for primary open-angle glaucoma (POAG). Consequently, it is particularly valuable to investigate TM characteristics, which, in turn, facilitates the development of new treatments for POAG. Since 2006, the advancement in induced pluripotent stem cells (iPSCs) provides a new tool to (1) model the TM in vitro and (2) regenerate degenerative TM in POAG. In this context, we first summarize the current approaches to induce the differentiation of TM-like cells from iPSCs and compare iPSC-derived TM models to the conventional in vitro TM models. The efficacy of iPSC-derived TM cells for TM regeneration in POAG models is also discussed. Through these approaches, iPSCs are becoming essential tools in glaucoma modeling and for developing personalized treatments for TM regeneration.