Topical Omega-3 Fatty Acids Eyedrops in the Treatment of Dry Eye and Ocular Surface Disease: A Systematic Review

Changes in conjunctival mononuclear phagocytes and suppressive activity of regulatory macrophages in desiccation induced dry eye

PURPOSE

To evaluate the effects of dry eye on conjunctival immune cell number and transcriptional profiles with attention to mononuclear phagocytes.

METHODS

Expression profiling was performed by single-cell RNA sequencing on sorted conjunctival immune cells from non-stressed and C57BL/6 mice subjected to desiccating stress (DS). Monocle 3 modeled cell trajectory, scATAC-seq assessed chromatin accessibility and IPA identified canonical pathways. Inflammation and goblet cells were measured after depletion of MRC1+ MΦs with mannosylated clodronate liposomes.

RESULTS

Mononuclear phagocytes (monocytes, MΦs, DCs) comprised 72 % of immune cells and showed the greatest changes with DS. Distinct DS induced gene expression patterns were seen in phagocytes classified by expression of Ccr2 and [Timd4, Lyve1, Folr2 (TLR)]. Expression of phagocytosis/efferocytosis genes increased in TLF+CCR2- MΦs. Monocytes showed the highest expression of Ace, Cx3cr1, Vegfa, Ifngr1,2, and Stat1 and TLF-CCR2+ cells expressed higher levels of inflammatory mediators (Il1a, Il1b, Il1rn, Nfkb1, Ccl5, MHCII, Cd80, Cxcl10, Icam1). A trajectory from monocyte precursors branched to terminate in regulatory MΦs or in mDCs via transitional MΦ and cDC clusters. Activated pathways in TLF+ cells include phagocytosis, PPAR/RXRα activation, IL-10 signaling, alternate MΦ activation, while inflammatory pathways were suppressed. Depletion of MRC1+ MΦs increased IL-17 and IFN-γ expression and cytokine-expressing T cells, reduced IL-10 and worsened goblet loss.

CONCLUSIONS

Dryness stimulates distinct gene expression patterns in conjunctival phagocytes, increasing expression of regulatory genes in TLF+ cells regulated in part by RXRα, and inflammatory genes in CCR2+ cells. Regulatory MΦs depletion worsens DS induced inflammation and goblet cell loss.

Dry Eye in Diabetes: The Indian Diabetic and Endocrine Eye Diseases (INDEED) Review

Dry eye disease (DED) is an inadequately addressed condition in the diabetes management process and can significantly impact the quality of life and self-care. Therefore, it was imperative to review DED in the diabetic population. The aim of this article was to obtain insights into the correlation between dry eye and diabetes, with a focus on data published in the Indian population. A comprehensive literature review was performed using MEDLINE and Google Scholar, along with an internet-based search of publicly available information and peer-reviewed publications that may not have been indexed in these databases. The recommendations from several important societies for patients with DED have also been reviewed. Major aspects commonly associated with DED and diabetes have been addressed, and specific suggestions for screening, diagnosis and treatment have been described. Therefore, this review could be an invaluable resource for doctors managing patients with both conditions.

Oxygen, the Paradox of Life and the Eye

Oxidative stress, caused by the formation of free radicals, such as reactive oxygen species (ROS), leads to cell and tissue degradation, contributing to various diseases and aging. While oxygen is essential for aerobic organisms, it inevitably causes oxidative stress. Antioxidants protect against damage from free radicals, and oxidative stress arises when an imbalance occurs between free radical production and antioxidant defenses. However, when investigating whether an excess of antioxidants, almost eliminating oxidative stress, could benefit aging and disease susceptibility, it was observed that a basic level of oxidative stress appears necessary to maintain the correct homeostasis of tissues and organs and life in general. Therefore, this review aimed to compile the most significant and recent papers characterizing and describing the dual role of oxygen as a molecule essential for life and as a precursor of oxidative stress, which can be detrimental to life. We conducted targeted searches in PubMed and Google browsers to gather all relevant papers. We then focused on the eye, an organ particularly vulnerable due to its high metabolic activity combined with direct exposure to light and environmental pollutants, which produces a substantial number of free radicals (mainly ROS). We present a curated selection of relevant literature describing the main ocular pathologies of the posterior and anterior segments of the eye, highlighting oxidative stress as a significant contributing factor. Additionally, we report how endogenous and exogenous antioxidants can mitigate the development and progression of these diseases. Finally, we consider a frequently overlooked aspect: the balance between oxidants and antioxidants in maintaining the homeostatic equilibrium of tissues and organs. It is widely recognized that when oxidants overwhelm antioxidants, oxidative stress occurs, leading to negative consequences for the organism's homeostasis. However, we emphasize that a similarly dangerous situation can arise when the presence of antioxidants overwhelms the production of free radicals, drastically reducing their amount and adversely affecting aging and longevity. Unfortunately, no specific studies have addressed this particular situation in the eye.

Recent advances in age-related meibomian gland dysfunction (ARMGD)

Meibomian glands (MGs), located within the tarsal plate of the eyelid, secrete meibum which is the lipid-rich secretion necessary for stabilizing the tear film and preventing tear evaporation. Changes in the quality and quantity of meibum produced causes MG dysfunction (MGD), the leading cause of evaporative dry eye disease (EDED). MGD is an underdiagnosed disease and it is estimated that, in the US, approximately 70 % of the population over 60 have MGD. Three forms of MGD occur based on their meibum secretion: hyposecretory, obstructive, and hypersecretory MGD. The pathophysiology of MGD remains poorly understood, however aging is the primary risk factor. With age, MGs undergo various age-related changes, including decreased acinar basal cell proliferation, hyperkeratinization, MG atrophy, and eventual MG drop-out, leading to age-related MGD (ARMGD). Additionally, studies have suggested that MGs can suffer inflammatory cell infiltration and changes innervation patterns with aging, which could also contribute towards ARMGD. This review focuses on how the aging process affects the MG, and more importantly, how age-related changes to the MG can lead to MG atrophy and MG drop-out, ultimately leading to ARMGD. This review also highlights the most recent developments in potential therapeutic interventions for ARMGD.

Nanoemulsion Loaded with Clotrimazole Based on Rapeseed Oil for Potential Vaginal Application-Development, Initial Assessment, and Pilot Release Studies

Vaginal candidiasis (VC) is an emerging global hardly treated health issue affecting millions of women worldwide. In this study, the nanoemulsion consisting of clotrimazole (CLT), rapeseed oil, Pluronic F-68, Span 80, PEG 200, and lactic acid was prepared using high-speed and high-pressure homogenization. Yielded formulations were characterized by an average droplet size of 52-56 nm, homogenous size distribution by volume, and a polydispersity index (PDI) < 0.2. The osmolality of nanoemulsions (NEs) fulfilled the recommendations of the WHO advisory note. NEs were stable throughout 28 weeks of storage. The stationary and dynamic (USP apparatus IV) pilot study of the changes of free CLT over time for NEs, as well as market cream and CLT suspension as references, were conducted. Test results of the changes in the amount of free CLT released from the encapsulated form were not coherent; in the stationary method, NEs yielded up to 27% of the released CLT dose within 5 h, while in the USP apparatus IV method, NEs released up to 10% of the CLT dose. NEs are promising carriers for vaginal drug delivery in the treatment of VC; however, further development of the final dosage form and harmonized release or dissolution testing protocols are needed.

Is fat the future for saving sight? Bioactive lipids and their impact on glaucoma

Glaucoma is characterized by a continuous loss of retinal ganglion cells. The cause of glaucoma is associated with an increase in intraocular pressure (IOP), but the underlying pathophysiology is diverse and, in most cases, unknown. There is an indisputable unmet need to identify new pathways involved in glaucoma pathogenesis. Increasing evidence suggests that bioactive lipids may be critical in the development and progression of glaucoma. Preclinical and clinical bioactive lipid targets exist and are being developed. In this review, we aim to shed light on the potential of bioactive lipids for the prevention, diagnosis, prognosis, and treatment of glaucoma by asking the question "is fat the future for saving sight".