Search Results (88)

Background/Objectives: The aim of this study was to investigate the effects of intraocular pressure (IOP)-lowering drops on the sublayers of the human tear film as assessed by a novel nanometer-resolution Tear Film Imager (TFI, AdOM, Israel). Methods: In a prospective, cross-sectional study, 98 eyes from 56 adult human subjects were imaged using the TFI. The dataset included data from 18 eyes from 12 subjects treated with preserved IOP-lowering drops and 80 eyes from 44 control subjects not under ocular hypotensive therapy. Subjects in the IOP treatment group used a variety of IOP-lowering medications, including prostaglandin analogs, beta-blockers, carbonic anhydrase inhibitors, alpha agonists, and combination drops. A linear mixed effects model was used to assess the association between IOP-lowering therapy and tear film (TF) metrics, controlling for age and intra-individual correlation. The following parameters were measured: muco-aqueous layer thickness (MALT), muco-aqueous layer thinning rate (MALTR), lipid layer thickness (LLT), lipid map uniformity (LMU), inter-blink intervals (IBI), and lipid break-up time (LBUT). Results: Average ages significantly differed (p = 0.013) between the treatment group (66.5 years) and control group (average age 51.5 years), and thus results were adjusted for age accordingly. IOP was 17.1 mmHg in the treatment group and 16.1 mmHg in the control group. When analyzing the sublayers of the TF, MALTR had a significant association with IOP-lowering therapy after adjusting for age, with a difference of −52.68 nm/s; 95% confidence interval [−96.87, −8.48]; p-value = 0.020. Additionally, IBI was significantly associated with IOP-lowering therapy after log transformation (p = 0.049), with shorter IBI in the treatment group. All other metrics (MALT, LLT, LMU, and LBUT) were statistically insignificant (p > 0.05). Conclusions: These pilot results suggest that IOP-lowering drops may accelerate thinning of the TF, specifically the muco-aqueous layer. Longitudinal studies with significantly larger samples are needed to specify the differential impact of various ocular hypotensive therapies on the human TF and the clinical implications of these findings. Full article

Background/Objectives: Lipid layer thickness (LLT) is widely used to assess tear film status in dry eye disease (DED), but single-point measurements may not adequately reflect spatial lipid distribution driven by tear film dynamics. This study evaluated whether the combined assessment of inferior and superior corneal LLT provides additional clinical relevance for interpreting DED subtypes. Methods: This cross-sectional study included 614 eyes of 614 patients with DED. Inferior corneal LLT (LLT_inf) was measured using a tear interferometer, and superior corneal LLT (LLT_sup) was graded using an LED-based slit-lamp assessment. DED parameters, including meibomian gland expressibility (MGE), meibum quality, tear meniscus height, Schirmer I test, and fluorescein tear break-up patterns, were analyzed. Results: Low LLT_inf showed worse meibomian gland function, with higher MGE scores than in the high LLT_inf group (1.9 ± 0.8 vs. 1.2 ± 0.9, p < 0.001). Higher LLT_inf was associated with lower aqueous parameters, and aqueous deficiency was observed in 57.4% of the high LLT_inf group increasing to 83.0% when LLT_sup was low. Combined LLT_inf–LLT_sup assessment improved the prediction of aqueous deficiency compared with LLT_inf alone (AUC, 0.719 vs. 0.559). Improvement for moderate-to-severe MGD was smaller (AUC 0.731 vs. 0.653). Conclusions: LLT reflects not only lipid secretion, but also aqueous-driven distribution. The combined assessment of LLT_inf and LLT_sup may improve the interpretation of LLT findings and provide additional insight into tear film dynamics in DED. However, its predictive performance remains moderate, suggesting that this approach is considered a complementary interpretive framework rather than a standalone diagnostic tool. Full article

Background and Objectives: Tamoxifen, a cornerstone selective estrogen receptor modulator in breast cancer therapy, is increasingly recognized to be associated with retinal toxicity characterized by mitochondrial dysfunction, oxidative stress, lipid peroxidation, and oxidative DNA injury. By targeting mitochondrial bioenergetic dysfunction and redox disequilibrium, adenosine triphosphate (ATP) emerges as a biologically plausible candidate for retinal cytoprotection. This study aimed to evaluate the protective effect of ATP against tamoxifen-induced retinal toxicity in a rat model. Materials and Methods: Twenty-four male albino Wistar rats were randomly assigned to four groups: healthy control (HG), ATP-alone (ATPG, 4 mg/kg, intraperitoneally), tamoxifen-alone (TAMG, 5 mg/kg, orally), and tamoxifen plus ATP-treated (ATAG; ATP, 4 mg/kg, intraperitoneally; tamoxifen, 5 mg/kg, orally). Treatments were administered once daily for 30 days. Oxidative stress markers (malondialdehyde, total glutathione), antioxidant enzyme activities (superoxide dismutase, catalase), and oxidative DNA damage (8-hydroxy-2′-deoxyguanosine) were assessed in ocular tissues. Retinal histopathological evaluation included hematoxylin–eosin staining with semiquantitative assessment of edema, vascular congestion, polymorphonuclear leukocyte infiltration, and cytoplasmic vacuolization, together with quantitative measurements of retinal layer thicknesses and ganglion cell layer (GCL) cell counts. Results: Tamoxifen administration induced marked oxidative stress, antioxidant depletion, and increased oxidative DNA damage in ocular tissues, accompanied by significant thickening of retinal layers, reduced GCL cell counts, and pronounced disruption of retinal architecture. By comparison, ATP co-administration significantly suppressed lipid peroxidation and restored antioxidant defenses, thereby reducing oxidative DNA damage and preserving retinal structural integrity, as reflected by partial normalization of retinal layer thicknesses, preservation of GCL cell counts, and the presence of only mild residual edema. Conclusions: These findings indicate that ATP attenuates tamoxifen-induced retinal toxicity by supporting mitochondrial energy balance and redox homeostasis. Accordingly, ATP administration may represent a promising protective approach for reducing retinal injury associated with long-term tamoxifen therapy. Full article

Background/Objectives: Corneal epithelial thickness (CET) alterations reflect distinct mechanisms in aqueous-deficient and evaporative dry eye disease (DED) subtypes. In this study, we compare the CET profiles between patients with Sjögren’s syndrome (SS) and those with meibomian gland dysfunction (MGD) to elucidate the underlying mechanisms. Methods: We retrospectively analyzed 30 patients with SS and 30 age- and sex-matched with MGD. Assessments included corneal staining, Ocular Surface Disease Index (OSDI), tear meniscus height (TMH), non-invasive breakup time, lipid layer thickness (LLT), and anterior segment optical coherence tomography (AS-OCT) CET mapping. Regional CET and superior–inferior asymmetry were compared. Results: The SS group exhibited higher corneal staining scores (2.18 ± 1.23 vs. 1.03 ± 1.18, p = 0.001) and lower TMHs (0.14 ± 0.06 vs. 0.18 ± 0.07 mm, p = 0.013), while the MGD group reported greater OSDI scores (40.39 ± 22.49 vs. 31.25 ± 22.81, p = 0.029). A significantly thinner central epithelium (p = 0.043) and localized inferior paracentral thinning (2–5 mm zone, p = 0.008) were noted in SS. Corneal staining was identified as the primary independent predictor of central and inferior CET reduction in both groups. In the MGD group, LLT was associated with the preserved inferior CET (p = 0.045) and superior–inferior thickness difference (p = 0.015). Conclusions: Distinct structural signatures are observed between DED subtypes. SS features central/inferior thinning from aqueous deficiency-mediated friction, whereas MGD shows a relatively preserved epithelial thickness influenced by LLT. Regional CET analysis may provide mechanistic insights into DED subtyping. Full article

Background/Objectives: To investigate whether chronic cosmetics use near or directly on the eyelid margin contributes to tear film instability and meibomian gland dysfunction. Methods: Subjects were enrolled in one of three groups: those who rarely wear makeup (No-M), those who wear it frequently but only outside the eyelid margin (Min-M), and those who wear it frequently and directly on the eyelid margin (W-M). Subjects were assessed for dry eye signs and symptoms by a masked examiner. Lipid layer thickness (LLT), tear meniscus height, meibomian gland excreta grade, number of glands secreting, corneal and conjunctival staining and tear breakup time were assessed. Results: 10 No-M, 18 Min-M, and 21 W-M subjects completed the study. Average fluorescein breakup time was 4.6 s in each group (p = 0.839, 1-way ANOVA). There were higher scores (worse findings) in the marginal eyeliner sample for symptoms (modified Schein, OSDI, SPEED), Oxford and total NEI staining and lower lid meibomian secretions. The W-M group demonstrated a statistically significant increase in the meibomian gland excreta grade (a worsening) compared to the No-M group (mean grades 1.2 and 0.55 respectively; Tukey test, adjusted p < 0.05, 95% CI 0.055–1.187). LLT, tear breakup time, eyelid marginal signs, and meibomian gland dropout had no differences among groups. Conclusions: Eyeliner wear both outside and on the eyelid margin demonstrated increased ocular staining and decreased gland excretion quality, compared to non-makeup users. The meibomian gland excreta decrement may lead to worsening meibomian gland function and potentially glandular atrophy over time. Full article

Background/Objectives: Rosacea is a chronic inflammatory dermatosis that may involve the eye, causing surface and adnexal damage that can precede cutaneous signs. Detecting subclinical ocular changes is clinically important because early ocular surface dysfunction may be missed on routine examination yet progress to corneal complications, allowing earlier preventive management when identified. We prospectively evaluated subclinical ocular alterations in cutaneous rosacea using a combined, fully non-invasive high-tech imaging workflow—tear film interferometry, infrared meibography, and exploratory retinal optical coherence tomography angiography (OCT-A)—including patients without clinically evident ocular involvement. Methods: Sixteen patients with cutaneous rosacea (mean age 44.3 ± 11.2 years; 4 males, 12 females) were enrolled and divided into: Group 1—rosacea with clinically evident ocular involvement (n = 11); Group 2—rosacea without clinical ocular involvement (n = 5). Six age-matched healthy subjects served as controls (Group 3). All underwent LipiView II^® interferometry and meibography to quantify lipid-layer thickness (LLT, nm) and meibomian gland (MG) loss score (1 = normal–4 = severe), plus retinal OCT-A (Optovue Inc., Fremont, CA, USA). ANOVA with post hoc Tukey test assessed inter-group differences. Results: OCT-A showed no significant alterations in superficial or deep retinal plexuses across groups (p > 0.05). Conversely, LLT was significantly reduced in both rosacea groups vs. controls (OD: 45.5 ± 21.4 nm and 67.4 ± 10.1 nm vs. 92.7 ± 8.2 nm; OS: 40.4 ± 15.3 nm and 66.4 ± 10.1 nm vs. 96.0 ± 6.7 nm; p < 0.001). MG score was markedly higher (worse) in rosacea (OD: 3.63 ± 0.50 and 3.20 ± 0.83 vs. 1.83 ± 0.75; OS: 3.45 ± 0.68 and 3.40 ± 0.54 vs. 1.66 ± 0.81; p < 0.001). Ocular symptoms were reported by 85% of patients yet slit-lamp examination revealed surface alterations in 58% of asymptomatic cases. Conclusions: Tear film interferometry and meibography detect early ocular surface impairment in rosacea—even in the absence of clinical signs—while retinal microvasculature appears unaffected. Routine ophthalmologic screening of all rosacea patients could enable prompt treatment of subclinical dysfunction, potentially preventing corneal complications. Retinal OCTA metrics were not significantly different in this small pilot cohort, and these negative findings should be interpreted cautiously pending larger studies. Full article

Body condition, the relative amount of energy reserves in an individual, reflects nutritional status and overall health in marine mammals and can indicate the influence of stressors on individuals. Energy in marine mammals is primarily stored as lipids within adipocytes in blubber tissue, making blubber thickness a common proxy for body condition. However, blubber also serves structural roles, complicating its use as a body condition indicator. Our objective was to assess the relationship between adipocyte size, a common measure of cetacean adiposity, and blubber thickness in beluga whales (Delphinapterus leucas). We used mixed-effect generalized linear models to test how sex and blubber layer influenced this relationship. We found a significant positive relationship between adipocyte size and blubber thickness in male but not female beluga whales, suggesting sex-specific differences in fat storage or mobilization. Blubber thickness may be maintained in female beluga whales during periods with low energy reserves, for example during gestation and lactation, to preserve buoyancy, insulation, and hydrodynamism, which may be especially important when supporting swimming calves. Continuing to develop methods to assess beluga whale health will further our understanding of the impact of current and future stressors on beluga whale populations. Full article

Studying the mechanisms by which Gram-negative heterotrophic bacteria transition from active metabolism to dormancy is an important task, as it is directly related to the problem of bacterial antibiotic resistance and the spread of nosocomial infections. Using electron microscopy, microbiology, and molecular modeling, we investigated the dose-dependent mechanisms of action of 4-hexylresorcinol (4HR), a chemical analog of the anabiosis autoinducer, on the cell membranes of Gram-negative bacteria (using Escherichia coli as an example), leading to the formation of stressed, dormant, and mummified cells. It was shown that 4HR penetrates membranes equally easily both as single molecules and as micelles, distributing itself across the membrane so that the hydrocarbon radicals are aligned parallel to the lipid tails. When micelles penetrate the membrane, uneven distribution of 4HR within and between leaflets occurs, as well as lipid redistribution within the membrane, leading to the appearance of a third peak on the phospholipid electron density profile and a third black band in the membrane region in TEM images of such cells. At 4HR concentrations in solution of 200 µM, its micelles cover the cell membranes in a thick layer, penetrate into the membrane, and completely saturate it. Even higher concentrations create agglomerates or actually micellar arrays within the cell membranes, leading to cell death through mummification. Full article

Objectives: To systematically review and quantitatively synthesize lipid layer thickness (LLT) measurements in soft contact lens (CL) wearers obtained in the presence and absence of contact lenses in situ. Methods: A systematic literature search of PubMed, Scopus, and Web of Science databases was conducted in accordance with PRISMA guidelines. Six studies meeting predefined inclusion criteria were included. Pooled mean LLT values were calculated using fixed-effects models, with heterogeneity, sensitivity analyses, and publication bias assessed. Results: In the absence of contact lenses, pooled LLT data from 86 healthy CL wearers yielded a mean LLT of 62.11 nm (95% CI: 47.33–76.90 nm). In the presence of contact lenses, pooled data from 330 subjects demonstrated a mean LLT of 69.52 nm (95% CI: 56.33–82.70 nm). Although LLT values were numerically higher with contact lens wear, the substantial overlap of confidence intervals indicated no consistent or statistically demonstrable difference between conditions. Conclusions: This meta-analysis provides the first quantitative synthesis of LLT in CL wearers and highlights the need for standardized methodologies to clarify the clinical relevance of LLT in contact lens-related tear film assessment. Full article

Alzheimer’s disease (AD) is marked by cognitive decline, and also by retinal degeneration. Having in mind that docosahexaenoic acid (DHA, 22:6n − 3) is a safe, low-cost, and pivotal fatty acid for brain health and sustained cognitive function, this study exploits environmentally friendly non-fish sources as potential dietary supplements enriched with DHA to prevent or reverse AD. Forty 5xFAD transgenic male mice, aged five weeks old, were randomly distributed by five body weight-matched dietary groups (with eight animals each) and fed isocaloric diets based on the AIN-93M standard formulation for rodents for 6 months. Except for the control feed (without supplementation), each diet contained a modified lipidic fraction supplemented with 2% of the following: (1) linseed oil (LSO, rich in alpha-linolenic acid (ALA, 18:3n − 3)); (2) cod liver oil (fish oil, FO, rich in both DHA and eicosapentaenoic acid (EPA, 20:5n − 3)); (3) Schizochytrium sp. microalga oil (Schizo, with 40% of DHA); and (4) commercial DHASCO (DHASCO, with 70% of DHA). The aim of this study was to measure retinal neural layer thickness, calculate ganglion cell layer (GCL) density, and assess retinal injury by means of immunohistochemical staining for β-amyloid plaques deposition, TAU protein levels, and IBA1, as hallmark features of AD progression, in order to elucidate the effects of different dietary DHA treatments in Alzheimer’s retinas. Although no statistical differences were observed across retinal layer thicknesses depending on the diet (p > 0.05), there was a consistent pattern for slightly increased retinal thickness in 5xFAD mice fed fish oil relative to the others for the measurement of total layers, in general and for the inner segment/outer segment layer, the outer nuclear layer, the outer plexiform layer, the inner nuclear layer, and the inner plexiform layer, in particular. The ganglion cell layer (GCL) density was increased in 5xFAD mice fed the DHASCO oil diet relative to the control (p < 0.05), suggesting a benefit of DHA supplementation on the number of viable ganglion cells. No positive staining was observed for β-amyloid plaques deposition or the neuroinflammatory marker, IBA1, corroborating previous findings in human AD retinas. Conversely, the internal retinal layers showed intense TAU immunostaining. Immnunostained TAU area was significantly reduced in 5xFAD mice fed a fish oil diet compared to control (p < 0.05), although the number of TAU-positive cells did not differ across diets (p > 0.05). The retinal protected integrity derived from the benefits of DHA supplementation found, either from fish oil or DHASCO oil, underscores the potential of retinal biomarkers as non-invasive indicators of cognitive decline and overall brain health, opening new avenues for investigating AD pathophysiology in the retina. Full article

Egg quality is a critical economic trait in poultry production, influencing consumer preference and production efficiency. The genetic and epigenetic regulation of egg quality involves complex biological pathways across various traits such as shell quality, albumen composition, and yolk biochemistry. This review synthesizes recent advances in the genetic, molecular, and epigenetic mechanisms that determine poultry egg quality. Specifically, it focuses on external traits such as eggshell strength, color, and thickness, and internal traits including albumen height, yolk composition, and the Haugh unit. Through genome-wide association studies (GWAS), quantitative trait loci (QTL) mapping, whole-genome sequencing (WGS), and multi-omics approaches, key candidate genes such as OC-116, CALB1, CA2 (shell formation), OVAL, SPINK5, SERPINB14 (albumen quality), and FGF9, PIAS1, NOX5 (lipid metabolism) have been identified. These genes play a pivotal role in shell biomineralization, albumen protein regulation, and yolk lipid transport. This review also explores the heritability of these traits, emphasizing the challenges posed by polygenic architecture and the influence of environmental factors. Furthermore, it addresses the dynamic spatiotemporal regulation of egg quality traits, including epigenetic layers such as DNA methylation, histone modifications, RNA methylation, and post-translational protein modifications. This paper highlights the application of these findings to breeding programs via genomic selection, marker-assisted breeding, and epigenetic engineering approaches. Future directions for precision breeding and the development of functional eggs with enhanced quality are also discussed. Full article

Objectives: To compare the safety and efficacy of a prototype electronic heating device, Meiboleyes^®, with the BRUDER Moist Heat Eye Compress for the treatment of Meibomian Gland Dysfunction (MGD). Methods: Adults with evidence of active MGD (Ocular Surface Disease Index [OSDI] score ≥ 13, fluorescein tear break-up time [TBUT] < 10 s and meibomian gland secretion score ≤ 12 for 15 glands of the lower lid) were enrolled in this prospective, randomised, parallel group, investigator-masked dispensing study (Australian New Zealand Clinical Trials Registry–ACTRN12624000175572). Meibomian gland secretion (MGS) score and number of meibomian glands yielding liquid secretion (MGYLS), lipid layer thickness, TBUT, ocular physiology and subjective symptoms were measured at baseline, and 2 weeks and 6 weeks following treatment. Linear mixed model analysis was conducted to compare the two groups and changes over time. Results: Ten participants (average age 38.7 ± 14.5 years) in the Meiboleyes^® test group, and 10 participants (average age 38.9 ± 14.8 years) in the BRUDER control group completed the study. MGS and MGYLS significantly improved in both treatment groups from baseline to the 2-week and 6-week follow-up visits (p ≤ 0.006). Significant improvements in TBUT (5.5 ± 1.8 vs. 8.3 ± 2.1 s, p = 0.044), OSDI scores (45.2 ± 15.1 vs. 27.4 ± 12.9, p = 0.027) and visual analogue scale dryness (55.3 ± 27.2 vs. 28.0 ± 23.9, p = 0.023) were observed in the Meiboleyes^® group only after 6 weeks of treatment. No other significant differences were observed over time or between groups. Eight treatment-related adverse events were reported in the Meiboleyes^® group compared to seven in the BRUDER group. All resolved without sequalae. Conclusions: The prototype Meiboleyes^® device was safe and effective for use as an at-home treatment for MGD when used twice daily for six weeks. Improvements in meibomian gland function were comparable to the BRUDER Moist Heat Eye Compress, but significant improvements in tear film stability and subjective comfort after 6 weeks of treatment were observed in the Meiboleyes^® group only. Full article

The study of the conformational stability of protein layers at the interface between gold surfaces and lipid membranes is crucial for determining the biological activity of these systems and understanding their interactions. The surfaces differ significantly in hardness: gold is a rigid substrate, while the POPC/POPS liposome layer is highly flexible. A quartz crystal microbalance with dissipation (QCM-D) monitoring method and multi-parametric surface plasmon resonance (MP-SPR) were used to determine the adsorption efficiency of lysozymes, the level of layer hydration, and changes occurring within the secondary structure and the thickness of the formed protein layer. In both methods, lysozyme adsorption on the gold surface was more effective at pH 4.0 than at pH 7.4. The lysozyme adsorption efficiency on the surface of the lipid layer was the same for both measurement conditions. In contrast, the affinity of lysozyme molecules to the lipid surface was higher than that of the gold surface. The composition of the secondary structure of lysozymes was monitored using the FT-IR method. Deconvolution of the Amide I band confirms the existence of different mechanisms underlying lysozyme molecule immobilization depending on the type of adsorption surface. Along with the change in the surface, there is a transition from the dominance of electrostatic to hydrophobic interactions, which significantly affects the structure of the interphase layer. High content of random structures on the lipid surface is evident, while, in the case of the gold surface, there is a decrease in random structures and the presence of antiparallel β-sheets. Interaction with the surface induces the transition of amyloidogenic domains of the protein to conformations, which are particularly susceptible to aggregation, consequently leading to oligomerization. Full article

In this study, we performed molecular dynamics simulations to investigate the lubricating properties of graphene situated between phospholipid membranes. Four membrane models were analyzed: 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) with 10% or 20% admixture of cholesterol, pure DMPC, and pure 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE). The simulations explored how varying the thickness of the water layer and the sliding speeds of graphene affect its interactions with the membranes. The results show that the presence of water and cholesterol significantly reduces the shear stress required to move graphene. In contrast, van der Waals interactions between graphene and lipids depend on membrane composition. These findings contribute to a better understanding of the potential of graphene as a biolubricant in biomedical applications. Full article

Atherosclerosis is common cardiovascular disease, leading to complications such as myocardial infarction and stroke. The main causes of these diseases are lipid accumulation and inflammation in large arteries. In this study, we investigated whether opioid receptor blockade impacts factors involved in atherosclerosis development. We administered naloxone to 8-week-old and 36-week-old ApoE^−/− mice, then examined the expression of Col1a1, and Col3a1 in the aorta, as well as the influence of naloxone administration on aortic collagen layer thickness and proteomic changes in the aorta. Additionally, we assessed the impact of naloxone on the splenic T-cell populations. The results showed that Col3a1 expression decreased in young mice but increased in older mice. In 36-week-old mice, naloxone administration led to an increase in aortic collagen layer thickness, but remained unchanged in young mice. Proteomic analysis identified 587 proteins that were altered following naloxone treatment. Our studies suggest that the opioid system is an important factor in atherosclerosis development. Full article