Anti-Inflammatory and Anti-Apoptotic Effects of Acer Palmatum Thumb. Extract, KIOM-2015EW, in a Hyperosmolar-Stress-Induced In Vitro Dry Eye Model

Modified Danzhi Xiaoyao Powder (MDXP) improves the corneal damage in dry eye disease (DED) mice through phagocytosis

ETHNOPHARMACOLOGICAL RELEVANCE

Modified Danzhi Xiaoyao Powder (MDXP) is a traditional Chinese medicine formula remedy for treating Dry Eye Disease (DED). It showed the function of dispersing stagnated liver Qi for relieving Qi stagnation and clearing heat, which can be effective in treating conditions such as Dry Eye Disease (DED) and irregular menstruation due to liver depression and fire transformation.

AIM OF THE STUDY

This study investigated the mechanism of the effect of MDXP in mice with DED.

MATERIALS AND METHODS

A DED model was induced in mice using chronic painful stimulation (tail clamping) in combination with Benzalkonium Chloride Solution drops administered in a dry box for 28 days. After modeling, the MDXP groups were given Chinese medicine with different dosages by gavage for 14 days. The following parameters were recorded in each group: body mass, anal temperature, tear secretion, tear film rupture time, and corneal fluorescein staining. Behavioral changes were evaluated by elevating cross-maze and open-field experiments. The levels of inflammatory factors serum tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), fcγR-mediated phagocytosis pathway cell division control protein 42 homolog (CDC42), actin-related protein 2/3 complex subunit 2 (ARPC2), and actin-related protein 3 (ACTR3) were measured by using Enzyme-linked immunoassay (ELISA), immunohistochemical staining, and real-time fluorescent qualitative polymerase chain reaction (RT-qPCR).

RESULTS

MDXP increased body mass and lowered body temperature, prolonged tear film break-up time, promoted tear secretion, repaired corneal damage, decreased horizontal and vertical scores, elevated percentage of open arm times and boom opening time percentage, and reduced the expression levels of inflammatory factors of TNF-α, IL-1β and pathway-related proteins CDC42, ARPC2, and ACTR3 in mice. MDXP also reduced the expression levels of inflammatory factors of TNF-α and IL-1β in human corneal endothelial cells (HCECs), mouse mononuclear macrophage cells (RAW264.7), and human myeloid leukemia mononuclear cells (THP-1).

CONCLUSIONS

MDXP can relieve tension and anxiety, inhibit apoptosis, reduce phagocytosis, reduce the expression of pro-inflammatory factors, repair corneal damage, and improve the symptoms in DED mice. The mechanism of action may be through the fcγR-mediated phagocytosis pathway.

Orientin Reduces the Effects of Repeated Procedural Neonatal Pain in Adulthood: Network Pharmacology Analysis, Molecular Docking Analysis, and Experimental Validation

Background

Premature infants often undergo painful procedures and consequently experience repeated procedural neonatal pain. This can elicit hyperalgesia and cognitive impairment in adulthood. Treatments for neonatal pain are limited. Orientin is a flavonoid C-glycoside that has repeatedly been shown to have pharmacological effects in the past decades. The aim of this study was to systematically explore the effect of orientin on repeated procedural neonatal pain using network pharmacology, molecular docking analysis, and experimental validation.

Methods

Several compound-protein databases and disease-protein databases were employed to identify proteins that were both predicted targets of orientin and involved in neonatal pain. A protein-protein interaction (PPI) network was constructed, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to explore the potential mechanism of action. Molecular docking analysis was employed to calculate the binding energy and visualize the interactions between orientin and potential target proteins. Finally, a mouse model of repeated procedural neonatal pain was established and orientin was administered for 6 days. The mechanical and thermal pain thresholds were assessed in neonates and adult mice. A Morris water maze was employed to investigate cognitive impairment in adult mice.

Results

A total of 286 proteins that were both predicted targets of orientin and involved in neonatal pain were identified. The hub proteins were SRC, HSP90AA1, MAPK1, RHOA, EGFR, AKT1, PTPN11, ESR1, RXRA, and HRAS. GO analysis indicated that the primary biological process (BP), molecular function (MF), and cellular component (CC) were protein phosphorylation, protein kinase activity, and vesicle lumen, respectively. KEGG analysis revealed that the mitogen-activated protein kinase (MAPK) signaling pathway may be the key to the mechanism of action. Molecular docking analysis showed the high binding affinities of orientin for MAPK1, MAPK8, and MAPK14. In mice, orientin inhibited the hyperalgesia in the pain threshold tests in neonates and adult mice and cognitive impairment in adult mice. Immunofluorescence showed that phosphorylated MAPK1 (p-ERK) protein levels in the hippocampus and spinal dorsal horn were downregulated by orientin.

Conclusion

The findings suggested that orientin alleviates neonatal pain, and the MAPK signaling pathway is involved.

Ocular Surface Allostasis-When Homeostasis Is Lost: Challenging Coping Potential, Stress Tolerance, and Resilience

The loss of ocular surface (OS) homeostasis characterizes the onset of dry eye disease. Resilience defines the ability to withstand this threat, reflecting the ability of the ocular surface to cope with and bounce back after challenging events. The coping capacity of the OS defines the ability to successfully manage cellular stress. Cellular stress, which is central to the outcome of the pathophysiology of dry eye disease, is characterized by intensity, continuity, and receptivity, which lead to the loss of homeostasis, resulting in a phase of autocatalytic dysregulation, an event that is not well-defined. To better define this event, here, we present a model providing a potential approach when homeostasis is challenged and the coping capacities have reached their limits, resulting in the stage of heterostasis, in which the dysregulated cellular stress mechanisms take over, leading to dry eye disease. The main feature of the proposed model is the concept that, prior to the initiation of the events leading to cellular stress, there is a period of intense activation of all available coping mechanisms preventing the imminent dysregulation of ocular surface homeostasis. When the remaining coping mechanisms and resilience potential have been maximally exploited and have, finally, been exceeded, there will be a transition to manifest disease with all the well-known signs and symptoms, with a shift to allostasis, reflecting the establishment of another state of balance. The intention of this review was to show that it is possibly the phase of heterostasis preceding the establishment of allostasis that offers a better chance for therapeutic intervention and optimized recovery. Once allostasis has been established, as a new steady-state of balance at a higher level of constant cell stress and inflammation, treatment may be far more difficult, and the potential for reversal is drastically decreased. Homeostasis, once lost, can possibly not be fully recovered. The processes established during heterostasis and allostasis require different approaches and treatments for their control, indicating that the current treatment options for homeostasis need to be adapted to a more-demanding situation. The loss of homeostasis necessarily implies the establishment of a new balance; here, we refer to such a state as allostasis.

Comparison of ocular surface assessment outcomes between healthy controls and patients with obstructive sleep apnea-hypopnea syndrome: a meta-analysis of the literature

Objective: This meta-analysis aims to determine whether ocular surface alterations are associated with disease severity in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). Methods: The protocol for this systematic review and meta-analysis was registered in PROSPERO. We conducted the search in six electronic databases (China National Knowledge Infrastructure, EMBASE, Cochrane Library, Web of Science, Wanfang, and PubMed) from since the construction of the databases to 30 December 2022. The standard mean difference (SMD) and correlation coefficients are reported as measures of the effect size in the presence of retrieved data. In addition, the random effects model or fixed effects model was used in a combined analysis. Stata 11.0 and R 3.6.1 were used for statistical analyses of the data. Results: A total of 15 studies satisfied the inclusion criteria for this study. The prevalence of floppy eyelid syndrome (FES) and dry eye syndrome in patients with obstructive sleep apnea-hypopnea syndrome was 40 and 48%, respectively. In addition, the Schirmer 1 value and tear break-up time (TBUT) were remarkably reduced in patients with OSAHS when compared to that of the controls. The ocular surface disease index (OSDI) scores, Oxford corneal staining scores, and the rates of loss in the meibomian glands were elevated in patients with obstructive sleep apnea-hypopnea syndrome when compared to that of the controls, especially those with severe disease. Moreover, the Schirmer 1 value and tear break-up time exhibited a negative correlation with the apnea-hypopnea index (AHI), and the OSDI showed a positive association with the apnea-hypopnea index. Conclusion: Patients with OSAHS had a greater prevalence of FES than the healthy controls. They also showed lower Schirmer 1 value and tear break-up time but had a higher OSDI, Oxford corneal staining scores, and rates of loss in the meibomian glands than the healthy controls. Clinical Trial Registration: (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=392527).

Development of In Vitro Dry Eye Models to Study Proliferative and Anti-Inflammatory Effects of Allogeneic Serum Eye Drops

This study aimed to develop valid in vitro models for preclinical evaluation of proliferative and anti-inflammatory effects of human allogeneic serum eye drops for dry eye disease (DED) treatment. A DED wound healing model was developed by analyzing the influence of coating and serum concentrations on human corneal epithelial (HCE-T) wound closure. Further, intralaboratory variance, freeze-thaw cycle effects, donor variability and stability assays were conducted. Interleukin-1β (IL-1β) and tumor necrosis factor α (TNFα) were used to induce the gene expression of matrix metalloproteinase 9 (MMP9), cyclooxygenase 2 (COX2), transforming growth factor-β (TGFβ) and IL-1β. MMP9 induction was optimized using a design-of-experiments (DoE) approach and applied to examine serum under static and dynamic conditions. MMP9 protein expression was analyzed by ELISA. The DED wound healing model detected proliferative effects of serum down to 1% with a small intralaboratory variance. Serum stability was shown over six months, donor variance could be detected, and freeze-thaw cycle effects did not affect wound closure. Serum decreased MMP9 expression on the gene and protein levels. The induction method was successfully optimized using DoE modeling and transferred to a dynamic setting mimicking tear film fluidics. The DED wound healing and inflammatory DED model present useful in vitro models for the preclinical evaluation of allogeneic serum eye drops without the use of animal experiments.

Using Network Pharmacology and Molecular Docking to Explore the Mechanism of Qiju Dihuang Pill against Dry Eye Disease

Background

Dry eye disease (DED) is a multifactorial disease of the ocular surface, which affects the quality of life and work efficiency of affected patients. The traditional Chinese medicine formula Qiju Dihuang Pill (QJDHP) has a good therapeutic effect on DED. However, the pharmacological mechanism is not clear.

Objective

To explore the mechanism of QJDHP in the treatment of DED based on network pharmacology.

Method

The active components in QJDHP were screened in Traditional Chinese Medicine Systems Pharmacology (TCMSP), and putative molecular targets of QJDHP were identified using the SwissTargetPrediction database. DED-related targets were screened by GeneCards and OMIM. We established protein-protein interaction (PPI) and core targets and corresponding active compound network by Cytoscape to identify the core targets and main compounds of QJDHP against DED. DAVID database was utilized for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Molecular docking was used to evaluate the binding activity between key active compounds and core targets.

Results

The results of network pharmacology showed that 253 targets of QJDHP were related to DED. PPI network analysis showed the 18 core targets. The binding affinity of docking results ranged from -5.7 to -9.3 kcal/mol, indicating a good docking effect. The results of GO enrichment analysis showed that the mechanism of QJDHP in the treatment of DED mainly involved biological processes such as apoptosis, oxidative stress, response to estrogen, angiogenesis, and the regulation of transcription factors. KEGG analysis showed that QJDHP may be regulated by the TNF signaling pathway, Toll-like receptor signaling pathway, MAPK signaling pathway, and estrogen signaling pathway in the treatment of DED.

Conclusion

In this study, we demonstrated the multicomponent, multitarget, and multichannel action mechanism of QJDHP in the treatment of DED and provided a foundation for further drug development research.

Therapeutic Effects of Acer palmatum Thumb. Leaf Extract (KIOM-2015E) on Benzalkonium Chloride-Induced Dry Eye in a Mouse Model

We determined the effects of two extracts from Acer palmatum Thumb. leaves (hot water extract KIOM-2015EW and 25% ethanol extract KIOM-2015EE) in a benzalkonium chloride (BAC)-induced dry eye mouse model. Dry eye was induced by 0.2% BAC for 2 weeks, followed by treatment three times (eye drop) or once (oral administration) daily with KIOM-2015E for 2 weeks. Treatment with both KIOM-2015EE and KIOM-2015EW resulted in a marked increase in tear volume production for the 4 days of treatment. The Lissamine Green staining score, TUNEL-positive cells, and inflammatory index were significantly decreased after 2 weeks. Topical KIOM-2015EE administration exhibited a greater improvement in decreasing the ocular surface staining scores, inflammation, dead cells, and increasing tear production in a dose-dependent manner compared with the other groups. Furthermore, KIOM-2015E significantly reduced the phosphorylation of NF-κB, which was activated in the BAC-treated cornea. Topical administration was much more effective than oral administration for KIOM-2015E and KIOM-2015EE was more effective than KIOM-2015EW. Application of KIOM-2015E resulted in clinical improvement, inhibited the inflammatory response, and alleviated signs of dry eye. These results indicate that KIOM-2015E has potential as a therapeutic agent for the clinical treatment of dry eye.

Temporal Change in Pro-Inflammatory Cytokine Expression from Immortalized Human Corneal Epithelial Cells Exposed to Hyperosmotic Stress

PURPOSE

To determine the metabolic activity, and cytokine expression over time from immortalized human corneal epithelial cells (HCECs) exposed to hyperosmotic stress.

METHODS

HCECs were cultured and expanded in DMEM/F-12 with 10% FBS. The cells were exposed to either normal media (295 mmol/kg) or hyperosmolar media (500 mmol/kg) for 0.25, 3, 6, and 12 hours. After each exposure duration, metabolic activity was quantified using alamarBlue, and a panel of pro-inflammatory cytokines (IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, TNF-α, IFN-γ, and IL-17A) was quantified using multiplexed electrochemiluminescence (Meso Scale Diagnostics, Rockville, MD).

RESULTS

Metabolic activity of the HCEC exposed to hyperosmolar conditions was significantly reduced at the 3-, 6-, and 12-hour mark compared to the control (all p < 0.01). There was no significant difference in cytokine expression between the hyperosmolar media and control at the 0.25- and 3-hour mark for all cytokines (all p ≥ 0.28). The difference in cytokine expression between the hyperosmolar media and the control was significant for IL-1β, IL-4, IL-6, IL-8, IL-12p70, IL-13, and TNF-α at the 6-hour mark (all p ≤ 0.02). No significant change in cytokine expression between the hyperosmolar media and control was noted for IL-2, IL-10, IL-17A, and IFN-γ (all p ≥ 0.74) at the 6-hour mark.

CONCLUSION

Hyperosmolar stress reduced cell metabolic activity and increased expression of IL-1β, IL-4, IL6, IL8, IL-12p70, IL-13, and TNF-α over a 6-hour period in an immortalized HCEC line.

Effect of the Sargassum angustifolium Extract on Methamphetamine-Induced Cytotoxicity in SH-SY5Y Cells

This study aimed to assess the effect of the Sargassum angustifolium extract in methamphetamine-induced SH-SY5Y cells death. The brown algae S. angustifolium was extracted with 80% ethanol. The SH-SY5Y cells were treated with different concentrations of methamphetamine to measure IC50 $\mathrm{..}$ The MTT test was used to assess the toxic effect of the S. angustifolium extract in SH-SY5Y cells. SH-SY5Y cells’ survival was measured while cells were treated with different concentrations of methamphetamine and S. angustifolium extract simultaneously. A specific kit measured intracellular ROS levels. Western blot analysis evaluated the expression of cytochrome C and Bax/Bcl2 ratio. The results showed that 5 mM methamphetamine approximately killed 50% of the cells, so it is considered IC50. The MTT test showed no toxicity effect for the S. angustifolium extract. 80, 160, 320, and 640 μg/ml of S. angustifolium extract prevented the occurrence of methamphetamine toxic effects in SH-SY5Y cells after 24 hours. Moreover, the S. angustifolium extract decreased ROS levels and cytochrome C release and reduced BaX/Bcl2 ratio in cells treated by methamphetamine. On the whole, it seems that the S. angustifolium hydroalcoholic extract has the potential to increase cell survival through in vitro antioxidant and antiapoptotic activities.

Anti-Inflammatory, Anti-Diabetic, Anti-Oxidant and Cytotoxicity Assays of South African Herbal Teas and Bush Tea Blends

South Africa is home to a variety of herbal teas, such as bush tea (Athrixia phylicoides DC.), honeybush tea (Cyclopia intermedia E. Mey and C. subternata Vogel), special tea (Monsonia burkeana Planch. ex Harv.), and rooibos tea (Aspalathus linearis (Burm.f.) R. Dahlgren) that are known to possess anti-oxidant, anti-inflammatory and anti-diabetic properties. The objective of this study was to determine the in vitro anti-oxidant activity of selected tea blends using 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays, as well as to assess their anti-inflammatory properties using the 15-lipoxygenase inhibitory assay. Furthermore, the study measured glucose utilisation in C2C12 myotubes. Lastly, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was used to test the safety of the tea extracts on Vero cells (African green monkey kidney cell line). Special tea and its blend with bush tea exhibited potent anti-oxidant and anti-inflammatory activity. The blending of bush tea with special tea at different ratios resulted in increased anti-oxidant activity. Although special tea had a level of cell toxicity, its toxicity was lowered during blending. All of the tea samples showed anti-diabetic effects, although with less potency as compared to insulin. The current investigation supports the use of blended herbal teas, and the positive anti-inflammatory effect of special tea warrants further research.

Vitexin Mitigates Staphylococcus aureus-Induced Mastitis via Regulation of ROS/ER Stress/NF-κB/MAPK Pathway

Mastitis, caused by a variety of pathogenic microorganisms, seriously threatens the safety and economic benefits of the dairy industry. Vitexin, a flavone glucoside found in many plant species, has been widely reported to have antioxidant, anti-inflammatory, antiviral, anticancer, neuroprotective, and cardioprotective effects. However, few studies have explored the effect of vitexin on mastitis. This study is aimed at exploring whether the antioxidant and anti-inflammatory functions of vitexin can improve Staphylococcus aureus-induced mastitis and its possible molecular mechanism. The expression profiles of S. aureus-infected bovine mammary epithelial cells and gland tissues from the GEO data set (GSE94056 and GSE139612) were analyzed and found that DEGs were mainly involved in immune signaling pathways, apoptosis, and ER stress through GO and KEGG enrichment. Vitexin blocked the production of ROS and increased the activity of antioxidant enzymes (SOD, GSH-PX, and CAT) via activation of PPARγ in vivo and in vitro. In addition, vitexin reduced the production of inflammatory cytokines (TNF-α, IL-1β, and IL-6) and inhibited apoptosis in MAC-T cells and mouse mammary tissues infected with Staphylococcus aureus. Moreover, vitexin decreased the expression of PDI, Ero1-Lα, p-IRE1α, PERK, p-eIF2α, and CHOP protein but increased BiP in both mammary gland cells and tissues challenged by S. aureus. Western blot results also found that the phosphorylation levels of JNK, ERK, p38, and p65 were reduced in vitexin-treated tissues and cells. Vitexin inhibited the production of ROS through promoting PPARγ, increased the activity of antioxidant enzymes, and reduced inflammatory cytokines and apoptosis by alleviating ER stress and inactivation MAPKs and NF-κB signaling pathway. Vitexin maybe have great potential to be a preventive and therapeutic agent for mastitis.

Olive Pomace Phenolic Compounds and Extracts Can Inhibit Inflammatory- and Oxidative-Related Diseases of Human Ocular Surface Epithelium

Oxidative- and inflammatory-related ocular surface diseases have high prevalence and are an emerging issue in ophthalmology. Olive pomace (OP) is the olive oil's industry main by-product, and is potentially environmentally hazardous. Nevertheless, it contains phenolic compounds with important bioactivities, like oleuropein (OL) and hydroxytyrosol (HT). The antioxidant and anti-inflammatory effects of four OP extracts (CONV, OPT(1-3)), pure OL and HT, and mixtures thereof were screened on human corneal (HCE) and conjunctival epithelial (IM-ConjEpi) cells. CONV was conventionally extracted, while OPT(1-3) were produced by pressurized liquid extraction. Thanks to their improved activity, CONV and OPT3 (HT-enriched) were selected for dose-dependent studies. Cells were stimulated with tumor necrosis factor-α or ultraviolet-B radiation, measuring interleukin (IL)-1β, IL-6, IL-8, and IL-17A as well as interferon γ-induced protein [IP]-10 secretion or intracellular ROS production, respectively. On HCE, both extracts and HT inhibited the secretion of most measured ILs, demonstrating a strong anti-inflammatory effect; while in IM-ConjEpi, all samples decreased IP-10 secretion. Moreover, HT, OL, and both extracts showed strong dose-dependent antioxidant activity in both cell lines. Compared with CONV, OPT3 was active at lower concentrations, demonstrating that intensified extraction techniques are selective towards targeted biomarkers. Hence, a high-value application as potential ocular surface therapy was proposed for the OP valorization.

Pathophysiology of Meibomian Glands - An Overview

Purpose: The meibomian glands are located in the tarsal plate of the upper and lower eyelid and are responsible for the production of a lipid-rich secretion, the meibum, which forms the outer component of the tear film. Meibomian gland dysfunction results in excessive evaporation of the tear film and is the leading cause of dry eye disease (DED). Despite the high prevalence of DED, the etiology of meibomian gland dysfunction is only basically understood. In addition, the molecular mechanisms of meibomian gland maturation and physiological function are currently the focus of research.Methods: A systematic literature search was performed using the main scientific databases, including all relevant published articles up to September 2020.Results: This article provides an overview of the current state of knowledge about meibomian gland stem cells, cell surface marker expression and PPARγ signaling, as well as the pathological causes of meibomian gland dysfunction.Conclusion: Androgen deficiency, hyperkeratinization, PPARγ signaling and inflammatory reactions including neutrophil extracellular traps (NETs) seem to be key factors within the pathological processes of the meibomian gland.

Protective Effects of Cyclosporine A Emulsion Versus Cyclosporine A Cationic Emulsion Against Desiccation Stress in Human Corneal Epithelial Cells

PURPOSE

To compare the protective effects of cyclosporine A emulsion (Restasis: 0.05% cyclosporine A) (CsAE) and cyclosporine A cationic emulsion (Ikervis: 0.1% cyclosporine A) (CsACE) on cellular inflammation, apoptosis, proliferation, and survival in an in vitro dry eye model.

METHODS

The concentration of CsA in CsAE and CsACE was verified using a liquid chromatography tandem mass spectrometry system. Human corneal epithelial cells were subjected to desiccation stress. Human corneal epithelial cells were incubated with or without 3 groups of cyclosporine A medium (CsAE 1:50, CsACE 1:50, and CsACE 1:100). p-NF-κB p65, p-IκBα, Bax, Bcl-xL, p-Erk1/2, and p-Akt levels were determined using Western blots, and TNF-α levels were quantified using an enzyme-linked immunosorbent assay.

RESULTS

The CsA concentration of CsACE 1:100 was nearly the same as that of CsAE 1:50. Compared with CsAE 1:50 (0.78 ± 0.19 fold), the p-NF-κB p65 level was further reduced in CsACE 1:50 (0.38 ± 1.20 fold) and 1:100 (0.29 ± 0.11 fold) as well as p-IκBα. Levels of TNF-α were also lower in CsACE 1:50 and 1:100 than in CsAE 1:50. Induction of the apoptotic protein Bax was significantly decreased in CsACE 1:50 and 1:100 compared with CsAE 1:50, whereas that of the antiapoptotic protein Bcl-xL was increased in CsACE 1:50 and 1:100. p-ERK1/2 and p-Akt levels were higher in CsACE 1:50 and 1:100 than in CsAE 1:50.

CONCLUSIONS

CsACE had more potent anti-inflammatory and antiapoptotic effects than CsAE in a transwell desiccation stress model. CsACE also enhanced proliferation and survival factors under desiccation stress compared with CsAE in this in vitro dry eye model.

Ions, the Movement of Water and the Apoptotic Volume Decrease

The movement of water across the cell membrane is a natural biological process that occurs during growth, cell division, and cell death. Many cells are known to regulate changes in their cell volume through inherent compensatory regulatory mechanisms. Cells can sense an increase or decrease in their cell volume, and compensate through mechanisms known as a regulatory volume increase (RVI) or decrease (RVD) response, respectively. The transport of sodium, potassium along with other ions and osmolytes allows the movement of water in and out of the cell. These compensatory volume regulatory mechanisms maintain a cell at near constant volume. A hallmark of the physiological cell death process known as apoptosis is the loss of cell volume or cell shrinkage. This loss of cell volume is in stark contrast to what occurs during the accidental cell death process known as necrosis. During necrosis, cells swell or gain water, eventually resulting in cell lysis. Thus, whether a cell gains or loses water after injury is a defining feature of the specific mode of cell death. Cell shrinkage or the loss of cell volume during apoptosis has been termed apoptotic volume decrease or AVD. Over the years, this distinguishing feature of apoptosis has been largely ignored and thought to be a passive occurrence or simply a consequence of the cell death process. However, studies on AVD have defined an underlying movement of ions that result in not only the loss of cell volume, but also the activation and execution of the apoptotic process. This review explores the role ions play in controlling not only the movement of water, but the regulation of apoptosis. We will focus on what is known about specific ion channels and transporters identified to be involved in AVD, and how the movement of ions and water change the intracellular environment leading to stages of cell shrinkage and associated apoptotic characteristics. Finally, we will discuss these concepts as they apply to different cell types such as neurons, cardiomyocytes, and corneal epithelial cells.

Neuroprotective effects of Acer palmatum thumb. leaf extract (KIOM-2015E) against ischemia/reperfusion-induced injury in the rat retina

PURPOSE

The present study aimed to determine whether the administration of Acer palmatum thumb. leaf extract (KIOM-2015E) protects against the degeneration of rat retinal ganglion cells after ischemia/reperfusion (I/R) induced by midbrain cerebral artery occlusion (MCAO).

METHODS

Sprague-Dawley rats were subjected to 90 min of MCAO, which produces transient ischemia in both the retina and brain due to the use of an intraluminal filament that blocks the ophthalmic and middle cerebral arteries. This was followed by reperfusion under anesthesia with isoflurane. The day after surgery, the eyes were treated three times (eye drop) or one time (oral administration) daily with KIOM-2015E for five days. Retinal histology was assessed in flat mounts and vertical sections to determine the effect of KIOM-2015E on I/R injury.

RESULTS

A significant loss of brain-specific homeobox/POU domain protein 3A (Brn3a) and neuron-specific class III beta-tubulin (Tuj-1) fluorescence and a marked increase in glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS) expression were observed after five days in the PBS-treated MCAO group compared to the sham-operated control group. However, KIOM-2015E treatment reduced (1) MCAO-induced upregulation of GFAP and GS, (2) retinal ganglion cell loss, (3) nerve fiber degeneration, and (4) the number of TUNEL-positive cells. KIOM-2015E application also increased staining for parvalbumin (a marker of horizontal cell associated calcium-binding protein and amacrine cells) and recoverin (a marker of photoreceptor expression) in rats subjected to MCAO-induced retinal damage.

CONCLUSIONS

Our findings indicated that KIOM-2015E treatment exerted protective effects against retinal damage following MCAO injury and that this extract may aid in the development of novel therapeutic strategies for retinal diseases, such as glaucoma and age-related macular disease.

Toxicological effects of urban particulate matter on corneal and conjunctival epithelial cells

Exposure to urban particulate matter (UPM) is a high-risk factor for various ocular surface diseases, including dry eye syndrome. However, the effects of UPM on corneal and conjunctival epithelium damage have not been fully elucidated. In this study, we investigated the toxicological effects of UPM exposure at high concentrations by using in vitro cultures. The cell viability, mucin expression, and the secreted inflammatory mediators of corneal and conjunctival epithelial cells was observed at 24 h after exposure to UPM. The progression of cell cycle was also examined by flow cytometry at 24 h after exposure to UPM. UPM reduced cell viability in a dose-dependent manner and increased cell population in S and G2 phase. The expression of mucin-1 was attenuated by UPM exposure, but that of mucin-4 was not. UPM increased interleukin (IL)-6 release and decreased IL-8 release. The intensity of 2',7'-dichlorofluorescein diacetate (DCF-DA) was highest at 4 h of UPM exposure. In conclusion, these results suggest that UPM causes the disruption of corneal and conjunctival epithelium by decreasing cell viability, altering cell cycle, disrupting mucin, and regulating inflammatory mediators.

Long-Term Exposure to Urban Particulate Matter on the Ocular Surface and the Incidence of Deleterious Changes in the Cornea, Conjunctiva and Retina in Rats

We investigated the time-dependent deleterious ocular changes induced by urban particulate matter (UPM) in vitro and in vivo. UPM treatment decreased human corneal epithelial cell migration and survival. Fluorescein scores were consistently increased by UPM application for 16 weeks. One week of rest at 2 or 4 weeks led to a recovery trend, whereas two weeks of rest at 8 weeks induced no change. UPM treatment decreased the tear film break-up time at 2 weeks, which was thereafter maintained until 16 weeks. No changes were found after periods of rest. UPM-treated eyes exhibited greater corneal epithelium thickness than normal eyes at 2 weeks, which recovered to normal at 4 and 8 weeks and was significantly decreased at 16 weeks. Apoptotic cell number in the epithelium was increased at 2 weeks, which remained constant except at 8 weeks. IL-6 expression in the cornea of the right eye continually increased for 16 weeks, and significant recovery was only observed at 8 weeks after 2 weeks of rest. Ocular pressure was significantly increased in the right eye at 12 and 16 weeks. Topical UPM application to the eye induced deleterious changes to various closely related parts of the eye.

Absorption, metabolism, and bioactivity of vitexin: recent advances in understanding the efficacy of an important nutraceutical

vitexin, an apigenin-8-C-glucoside, is widely present in numerous edible and medicinal plants. vitexin possesses a variety of bioactive properties, including antioxidation, anti-inflammation, anti-cancer, neuron-protection, and cardio-protection. Other beneficial health effects, such as fat reduction, glucose metabolism, and hepatoprotection, have also been reported in recent studies. This review briefly discusses the absorption and metabolism of vitexin, as well as its influence on gut microbiota. Recent advances in understanding the pharmacological and biological effects of vitexin are then reviewed. Improved knowledge of the absorption, metabolism, bioactivity, and molecular targets of vitexin is crucial for the better utilization of this emerging nutraceutical as a chemopreventive and chemotherapeutic agent.

Osmotic stress induces apoptosis in extravillous trophoblast cells. Role of TRPV-1

In different tissues hyperosmolarity induces cell differentiation. Nevertheless an exacerbated hyperosmolar stress alters the normal cellular development. The transient receptor potential vanilloid 1 (TRPV-1) is a non-selective cation channel that is activated by hyperosmolarity and participates in many cellular processes. TPRV-1 is expressed in human placenta at term. Here, we evaluated the expression of TRPV-1 in first trimester extravillous trophoblast cells and its participation in the survival of these cells exposed to hyperosmolar stress. Our results showed that hyperosmolar stress up-regulates the expression of TRPV-1 and induces the apoptosis in Swan 71 cells. In addition, the inhibition of TRPV-1 abrogates the apoptotic events.

Osmokinetics: A new dynamic concept in dry eye disease

INTRODUCTION

Tear fluid osmolarity has been increasingly accepted as an accessible parameter in the diagnosis of ocular surface and dry eye disease. After having been proposed as the gold standard, recent results have put this into question. However, the most recent guidelines for dry eye disease identify specific values of osmolarity as thresholds to help to differentiate between various stages of severity of ocular surface disease. The limits of this approach were investigated to propose a new concept, that of osmokinetics.

MATERIALS AND METHODS

Available data on tear fluid osmolarity in normal and diseased eyes were compared. The possibility of normo-osmolar dry eye was investigated and repeated measurements of osmolarity performed.

RESULTS

The currently applied static model of a threshold value of osmolarity for diagnosing dry eye disease is apparently insufficient. Not only does it not take into account normo-osmolar dry eye, but it also applies too much significance to a single parameter. Instead, it was found that there is a daily variation in osmolarity (DVO), which appears to be higher in eyes with tear film deficiencies than in healthy eyes.

DISCUSSION

Tear film osmolarity does vary considerably throughout the day. Its value should be considered in a kinetic model taking into account the dynamics of osmolarity changes moreso than the current static model. The terms of osmotic stress and diurnal variation of osmolarity were found to offer a more physiological understanding of osmolarity.

CONCLUSION

A more dynamic model for osmolarity is presented in which not the value itself but the daily variation of osmolarity is identified. It is suggested that the amplitude of change in osmolarity over the course of a day or even shorter time periods could play a decisive role as a stress factor for the surface cells. The varying osmolar stress could be one of the key mechanisms leading to the cell death, inflammation, apoptosis, and goblet cell disappearance as observed in dry eye disease. Perhaps it is the mean osmolarity level at which these changes occur together with the magnitude of DVO which could identify the level of severity of dry eye disease.

Acer palmatum thumb. Ethanol Extract Alleviates Interleukin-6-Induced Barrier Dysfunction and Dextran Sodium Sulfate-Induced Colitis by Improving Intestinal Barrier Function and Reducing Inflammation

Ulcerative colitis is one inflammatory bowel disease (IBD) and is caused by diverse factors, including the extent and duration of intestinal inflammation. We investigated the effect of Acer palmatum thumb. ethanol extract (KIOM-2015E) on the expression of tight junction proteins and the levels of inflammation in the cell model induced with interleukin-6- (IL-6-) and mouse model of dextran sodium sulfate (DSS) induced with acute colitis. KIOM-2015E (100 mg/kg) was orally administered once per day to BALB/C mice with colitis induced by administration of 5% DSS in drinking water. KIOM-2015E did not affect viability in Caco-2 cells. Also, KIOM-2015E repaired the IL-6-induced intestinal barrier dysfunction in Caco-2 cells. Furthermore, KIOM-2015E recovered the loss of body weight and the abnormally short colon lengths in the DSS-induced model of acute colitis. Moreover, KIOM-2015E significantly inhibited the decrease of zonula occluden-1 and occludin in colonic tissue relative to the DSS-treated control group. KIOM-2015E also significantly inhibited the expression of IL-6 and tumor necrosis factor-α in the level of serum relative to the control group. Collectively, these data suggest that KIOM-2015E protects colitis principally by improving intestinal barrier function and promoting anti-inflammatory responses. In turn, these effects inhibit macrophage infiltration into the colon and thus may be a candidate treatment for IBD.