Mucin Layer Research Articles

The Effect of Long-Term Use of an Eyewash Solution on the Ocular Surface Mucin Layer.

The use of eyewash solutions in Japan, especially in patients with allergic conjunctivitis and contact lens wearers, has been increasing. Our aim was to investigate how the use of preservative-free eyewash solution in healthy eyes for one month affects corneal safety and ocular surface mucin. We analyzed 42 eyes of 21 individuals (17 males, four females; mean age: 36.1 ± 7.4 years) without ocular allergies, dry eyes, or other ocular diseases through a prospective study. Eyes were randomized to a wash group (group one) and a nonwash follow up group (group two). We evaluated the dry eye-related quality-of-life score (DEQS), tear film breakup time (TBUT), fluorescein staining score, mRNA expression of MUC5AC and MUC16, MUC16 immunohistochemistry, and MUC5AC periodic acid Schiff (PAS) staining. There was a significant decrease in DEQS scores after one month of eyewash use (p < 0.05). There were no significant differences in other evaluation items that were analyzed (all p > 0.05). Furthermore, no significant differences were observed between group one and group two in all endpoints (all p > 0.05). The results suggest that one month use of a nonpreserved eyewash solution has no detrimental effects on the tear film and the ocular surface mucins.

Overcoming the Anatomical and Physiological Barriers in Topical Eye Surface Medication Using a Peptide-Decorated Polymeric Micelle.

The sealed anatomical features of the eye and its physiological activity that rapidly removes drugs are called anatomical and physiological barriers, which are the cause of more than 90% of drug loss. This aspect remains a critical issue in eye surface medication. Thus, promoting tissue permeability of drugs as well as prolonging their retention on the eye surface can improve their bioavailability and enhance their therapeutic effects. Thanks to the existence of a negatively charged mucin layer on the eye surface, several peptide-decorated polymeric micelles were prepared to enhance the interaction between the micelle and eye surface, thus prolonging the drug retention on the eye surface and promoting its tissue permeability. Tacrolimus (also known as FK506) is a hydrophobic macrolide immunosuppressant used to treat dry eye syndrome and other eye diseases. However, its hydrophobic nature makes its delivery as a topical eye surface medication difficult, with the risk of side effects due to overdoses. Therefore, the aim of this work is to evaluate the ability of FK506 micelles in promoting their permeability on the eye surface. Our results showed that the positively charged nanomicelles could significantly prolong FK506 retention on the eye surface and enhance its corneal permeability in ex vivo and in vivo conditions. FK506 nanomicelles exhibited superior curing effects against dry eye diseases than the FK506 suspension and a commercial FK506 formula. It exerted better inhibitory effects on eye surface inflammation and corneal epithelium apoptosis when examined by a slip lamp and a transferase-mediated dUTP nick end labeling assay, respectively. Further assays revealed the higher suppressive effects on the expression of several inflammation-related factors at an mRNA and protein level. Hence, our results suggested that these positively charged nanomicelles might be a good drug delivery system for ocular surface medication.

Distinct Microbial Populations Exist in the Mucosa-associated Microbiota of Diarrhea Predominant Irritable Bowel Syndrome and Ulcerative Colitis.

The goal of this study was to observe the bacterial colonization in the intestinal mucosa in the patients with diarrhea predominant irritable bowel syndrome (IBS-D) and ulcerative colitis (UC), and compare the mucosa-associated microbiota among the IBS-D patients, UC patients and the healthy control, and explore the correlation of the mucosa-associated microbiota with clinical manifestations. A total of 20 IBS-D patients, 28 patients with UC (16 active, 12 inactive) and 16 healthy subjects were enrolled in the study. They all underwent colonoscopies in the Gastrointestinal Endoscopy Center in the Second Affiliated Hospital of Xi'an Jiaotong University from June 2016 to October 2016. The mucosa specimens were taken at the junction of rectum and sigmoid colon for fluorescent in situ hybridization (FISH). Then the observed mucosa-associated microbiota was counted and compared. (1) In the IBS-D patients, the mucosa-associated bacteria were found to colonize in the surface of mucosa and the adjacent mucin layer. And in active UC, Escherichia coli, and Bacteroides were found in the lamina propria, in addition to bacterial colonization in the above-mentioned areas. (2) The total count of mucosa-associated bacteria and the individual counts of E. coli, Clostridium, and Bacteroides were significantly increased, and Bifidobacteria significantly decreased (P<0.05) in the IBS-D patients and UC patients. Counts of Lactobacillus were decreased only in UC patients compared with the healthy control. And a significantly larger variation of the above-mentioned bacterial counts was found in the patients with UC, particularly in those with active UC, compared with those with IBS-D (P<0.05); the counts in the UC group were 1.3 to 5.3 times more or less than those in the IBS-D group. (3) Compared with healthy controls and IBS-D, the total count of bacteria and the individual counts of E. coli and Bacteroides in the lamina propria in active UC were significantly increased (P<0.05). (4) A significant negative correlation of the counts of Lactobacillus and Bifidobacteria with the defecation frequency and fecal characteristics (P<0.05) was found in the IBS-D patients; in those with UC, both the total count of bacteria and the individual counts of E. coli, Clostridium, Bacteroides, Lactobacillus, and Bifidobacteria were significantly correlated, positively or negatively, with the related clinical manifestations and the activity of the disease (P<0.05). Compared with the healthy control, intestinal microecology was changed most obviously in UC with much smaller differences though in the same direction in IBS-D. The translocation of some bacteria into the lamina propria was found in UC, particularly in active UC. The changes of mucosa-associated microbiota were related more or less to some clinical manifestations in IBS-D and UC.

Structural and functional analysis of four family 84 glycoside hydrolases from the opportunistic pathogen Clostridium perfringens.

The opportunistic pathogen Clostridium perfringens possesses the ability to colonize the protective mucin layer in the gastrointestinal tract. To assist this, the C. perfringens genome contains a battery of genes encoding glycoside hydrolases (GHs) that are likely active on mucin glycans, including four genes encoding family 84 GHs: CpGH84A (NagH), CpGH84B (NagI), CpGH84C (NagJ) and CpGH84D (NagK). To probe the potential advantage gained by the expansion of GH84 enzymes in C. perfringens, we undertook the structural and functional characterization of the CpGH84 catalytic modules. Here, we show that these four CpGH84 catalytic modules act as β-N-acetyl-D-glucosaminidases able to hydrolyze N- and O-glycan motifs. CpGH84A and CpGH84D displayed a substrate specificity restricted to terminal β-1,2- and β-1,6-linked N-acetyl-D-glucosamine (GlcNAc). CpGH84B and CpGH84C appear more promiscuous with activity on terminal β-1,2-, β-1,3- and β-1,6-linked GlcNAc; both possess some activity toward β-1,4-linked GlcNAc, but this is dependent upon which monosaccharide it is linked to. Furthermore, all the CpGH84s have different optimum pHs ranging from 5.2 to 7.0. Consistent with their β-N-acetyl-D-glucosaminidase activities, the structures of the four catalytic modules revealed similar folds with a catalytic site including a conserved -1 subsite that binds GlcNAc. However, nonconserved residues in the vicinity of the +1 subsite suggest different accommodation of the sugar preceding the terminal GlcNAc, resulting in subtly different substrate specificities. This structure-function comparison of the four GH84 catalytic modules from C. perfringens reveals their different biochemical properties, which may relate to how they are deployed in the bacterium's niche in the host.

Utilizing nanoparticles for improving anti-biofilm effects of azithromycin: A head-to-head comparison of modified hyaluronic acid nanogels and coated poly (lactic-co-glycolic acid) nanoparticles

HypothesisThe widespread resistance of bacteria to traditional antibiotic treatments has expedited the search for novel therapies against these pathogens. The hypothesis of this work is that two distinctively different polymeric delivery systems, specifically D-α-tocopherol polyethylene glycol 1000 succinate (TPGS)-poly(lactic-co-glycolic acid) (PLGA) nanoparticles and octenyl succinic anhydride-modified low molecular weight hyaluronic acid (OSA-HA) nanogels may be used to substantially improve the properties of azithromycin, allowing its use for effective treatment of Pseudomonas aeruginosa biofilm infections. ExperimentsAzithromycin was encapsulated in both delivery systems and the physicochemical properties of the loaded delivery systems, including size, surface charge and drug loading were evaluated. Additionally, particle interaction with a mucin layer, penetration into a bacterial biofilm, prevention of biofilm formation and eradication of pre-formed biofilms, the influence on production of virulence factors and bacterial motility as well as cytotoxicity towards hepatocytes and lung epithelial cells were compared head-to-head. FindingsThe TPGS-PLGA nanoparticles noticeably improved the antimicrobial activity and the biofilm prevention activity of azithromycin whereas the OSA-HA nanogels showed reduced mucin interactions together with improved reduction of pre-formed biofilms and maintained the low eukaryotic cell cytotoxicity of azithromycin.

Mucin Thin Layers: A Model for Mucus-Covered Tissues.

The fate of macromolecules of biological or pharmacological interest that enter the mucus barrier is a current field of investigation. Studies of the interaction between the main constituent of mucus, mucins, and molecules involved in topical transmucoidal drug or gene delivery is a prerequisite for nanomedicine design. We studied the interaction of mucin with the bio-inspired arginine-derived amphoteric polymer d,l-ARGO7 by applying complementary techniques. Small angle X-ray scattering in bulk unveiled the formation of hundreds of nanometer-sized clusters, phase separated from the mucin mesh. Quartz microbalance with dissipation and neutron reflectometry measurements on thin mucin layers deposited on silica supports highlighted the occurrence of polymer interaction with mucin on the molecular scale. Rinsing procedures on both experimental set ups showed that interaction induces alteration of the deposited hydrogel. We succeeded in building up a new significant model for epithelial tissues covered by mucus, obtaining the deposition of a mucin layer 20 Å thick on the top of a glycolipid enriched phospholipid single membrane, suitable to be investigated by neutron reflectometry. The model is applicable to unveil the cross structural details of mucus-covered epithelia in interaction with macromolecules within the Å discreteness.

Study of mucin interaction with model phospholipid membrane at the air–water interface

The aim of the present study was to determine the interfacial behavior of model biomembrane in the presence of mucin. The Langmuir monolayer technique was used to form a mixed protein–phospholipid film at the air–water interface. Using the surface pressure-area isotherms, the relaxation curves and adsorption experiment, the nature of interactions between mucin and dipalmitoylphosphatidylcholine (DPPC) components of the monolayers under physiological conditions, (characteristic of the vagina and oral cavity), was investigated. It has been shown that at pH 4.2 mucin molecules reveal a strong affinity to the model biomembrane, composed of zwitterionic DPPC, and probably interact with it through the hydrophobic interactions. At pH 6.8 very weak electrostatic interactions are possible between the positively charged quaternary ammonium groups present in the DPPC molecules and the negatively charged mucin molecules. Moreover, from the relaxation experiment we concluded that beneath the DPPC layer there is a layer made of mucin particles due to electrostatic attraction. This layer of mucin beneath the DPPC particles stabilizes the entire system, especially at physiologically significant surface pressure, i.e. at π = 30 mN/m.

Gut Barrier Function Is Improved in Infants Colonized by Bifidobacterium Longum Subsp. Infantis EVC001 (FS04-05-19)

ObjectivesThe gut epithelium is single-celled barrier that employs many different mechanisms that together provide the first line of defense to physically separate the gut epithelium from our gut microbiome. Notably, the epithelial barrier is protected by a mucin layer providing a physical barrier limiting pathogen access to the epithelial monolayer. We sought to assess how changes in the gut microbiome resulting from colonization by a single strain of Bifidobacterium longum subsp. infantis EVC001 could alter gut barrier function. MethodsFecal samples from this trial were assessed for: (1) endotoxin (lipopolysaccharide) concentration; (2) functional contributions to the gut microbiome by shotgun metagenome sequencing; and (3) fecal glycan profiles by mass spectrometry to assess gut epithelial barrier integrity via breakdown of colonic mucin glycoproteins. ResultsColonization with Bifidobacterium, including B. infantis EVC001, showed a significant four-fold reduction in fecal endoxtoxin levels and reductions in fecal inflammatory markers (P < 0.05). Shotgun metagenomics identified LPS-producing Enterobacteriaceae as the most significant contributor of virulence factors in the infant gut metagenome. These bacteria (primarily E. coli and Klebsiella spp.) were also significantly correlated with both mucolytic bacteria (e.g., Bacteroides) and the signatures of mucin breakdown, as assessed by mass spectrometric quantification of colonic mucin-derived glycans. Five different colonic-mucin specific glycans (3_1_1_0, 2_1_2_0, 2_1_1_1, 2_1_1_0, and 1_1_0_1) were significantly associated with microbiome composition (P < 0.05). Overall mucin glycans were inversely correlated with Bifidobacteriaceae abundance (Spearman’s rho −0.66, FDR-corrected P value 0.04). ConclusionsComplex interactions between the degradation of gut barrier function (e.g., mucin), the production of pro-inflammatory endotoxins, and the risk of infection by these bacteria coming in close contact with the gut epithelium suggest that B. infantis EVC001 can play a role in reducing these combined risks for neonates. Funding SourcesThis work was funded by Evolve Biosystems, Inc.

Analysis of cholinergic pathway-induced alterations at the intestinal mucosa and their association with enhanced resistance to lethal bacterial infection

Abstract The mucosal innate immune system represents the first line of defense against microorganisms invading the intestinal tract. Increasing evidence suggests that mucosal immune defenses are tightly regulated by immunological and neural pathways. We previously demonstrated that activation of the cholinergic pathway through the administration of a highly specific acetylcholinesterase inhibitor (AChEI), paraoxon, confers resistance to an oral infection by virulent S. typhimurium. This protection is mediated by enhanced innate anti-microbial mucosal defenses in the GI tract. In the present study, we investigated the involvement of different immune cell populations in the GI tract in the modulation of AChEI-mediated anti-Salmonella resistance. Morphological evaluation of intestinal tissue from control- or AChEI-treated mice revealed a significant thickening of the mucin layer and increased B and T lymphocytic infiltration into intestinal mucosa in the AChEI group. Multi-color flow cytometric analysis of iliac intraepithelial lymphocytes (IELs) showed that cholinergic stimulation increased the percentage of CD3+CD8+gamma/delta TCR+ cells. No significant alterations were observed in lamina propria cells. Our findings indicate that cholinergic pathway is able to modulate not only mucin-secreting cells but more importantly gamma/delta T cells, the cell population known to be involved in tissue homeostasis and repair as well as surveillance of the epithelial barrier.

Effect of molecular weight of hypromellose on mucin diffusion and oral absorption behavior of fenofibrate nanocrystal

We investigated the effect of variation in the molecular weight of hypromellose (HPMC) on the oral absorption of fenofibrate (FFB) nanocrystal. Four types of HPMC with different molecular weights and sodium dodecyl sulfate (SDS) were used as dispersion stabilizers for FFB nanocrystal suspension. Wet-milling of FFB crystal with HPMC and SDS formed diamond-shaped FFB nanocrystals with approximately 150 nm diameter. HPMC was strongly adsorbed onto the FFB nanocrystal interface, and the amount of HPMC adsorbed was not dependent on the molecular weight of HPMC. However, the decrease in the molecular weight of adsorbed HPMC led to an improvement in the permeability of FFB nanocrystal through the mucin layer. The decrease in molecular weight of HPMC enhanced the flexibility of FFB nanocrystal interface and effectively inhibited its interaction with mucin. This led to faster diffusion of FFB nanocrystal through mucin. In vivo oral absorption studies showed rapid FFB absorption from FFB nanocrystal formulations using HPMC of low molecular weights. The present study revealed that the molecular weight of the dispersion stabilizer for drug nanocrystal formulation should be taken into consideration to achieve improved absorption of poorly water-soluble drugs after oral administration.

Conjunctival Goblet Cells, the Overlooked Cells in Glaucoma Treatment

Glaucoma is the leading cause of irreversible blindness worldwide. Although no definitive cure exists, lowering of the intraocular pressure decreases the rate of progression in the majority of patients with glaucoma. Antiglaucomatous treatment modalities consist predominantly of chronic use of eye drops. It has become increasingly evident that long-term exposure to eye drops has a significant impact on the ocular surface, and thereby on patient compliance and quality of life. Maintenance of the ocular surface is highly dependent on a stable tear film. Conjunctival goblet cells (GCs) of the ocular surface play an important role in providing the innermost mucin layer of the tear film and are essential for maintaining the ocular surface homeostasis. Recent studies have reported severe side effects of antiglaucomatous drops on GCs. In particular, a preservative containing antiglaucomatous drops have been shown to affect the viability and functions of the GCs. Furthermore, GC density has been suggested as a potential predictor of surgical outcome after filtration surgery. The present review provides an overview of the current literature on the impact of antiglaucomatous eye drops on GCs as well as the impact on the ocular surface. Moreover, the existing evidence of a possible association between GC density and glaucoma filtration surgery outcome is summarized. We conclude that prostaglandin analogs spare the conjunctival GCs more compared with other antiglaucomatous drops and that GCs may be a good predictor of surgical outcome after filtration surgery. Overall, given the multiple functions of GCs in the ocular surface homeostasis, dedicated strategies should be adopted to preserve this cell population during the course of glaucoma.

Interactions of Transition Metal Dichalcogenide Nanosheets With Mucin: Quartz Crystal Microbalance With Dissipation, Surface Plasmon Resonance, and Spectroscopic Probing.

Ultrathin 2-dimensional transition metal dichalcogenides (TMDs) have become a class of high-potential materials in biomedicine due to their intriguing properties. They have been applied to solve biomedical challenges, such as biosensing, bioimaging, drug delivery, and cancer therapy. However, studies of the interactions between these materials and biomolecules are insufficient. Mucous tissue serves as a barrier to foreign hazardous substances and a gel layer for substance exchange. The main organic matter of mucous tissue is mucin, so it was selected as a model biomolecule to study its interactions with six different TMD nanosheets (NSs), including single-layered (SL), few-layered (FL), and small few-layered (SFL) MoS2 and WS2 NSs, using quartz crystal microbalance (QCM) with a dissipation monitor (QCM-D) and surface plasmon resonance (SPR). Additionally, UV absorption, fluorescence, and circular dichroism (CD) spectroscopy were applied to investigate the mechanism of the interactions and to study the conformational change of mucin. We found that the TMD NSs could adsorb on the mucin layer and affect its viscoelasticity. The results indicated that the SL WS2 NSs exhibited the highest initial absorption rate and the maximum absorption amount, while the SL MoS2 NSs exhibited the highest initial desorption rate. During the adsorption, the viscoelasticity variations of the mucin layer caused by the WS2 nanosheets were weaker than those caused by the MoS2 nanosheets. Furthermore, the conformational changes of mucin caused by the SL MoS2, SL WS2, and SFL MoS2 NSs were higher than those resulting from other TMD NSs. These findings provide important information on the interactions between TMD NSs and mucin and provide useful insights into the interfacial behavior of TMD NSs before they enter tissues.

Synthesis and Evaluation of Water Insoluble but Swellable Bioadhesive Polymer for Ocular Drug Delivery

Abstract: Introduction: Our main purpose of present study was to find out the effect of different crosslinking agents along with its concentration during polymer synthesis and to find the most suitable polymer for ocular drug delivery with optimum bioadhesive strength and less irritation potential. It was expected that the synthesized polymer will remain adhered to the conjunctival mucin layer thus preventing loss of drug by precorneal factors. Materials and Methods: Acrylic acid procured from Loba chemicals was polymerized with Divinyl glycol from Merck specialities Private limited, Divinylbenzene and 2, 5-dimethyl-1, 5-hexadiene from Alfa Aesar to form water insoluble swellable polymer. Different parameters like density, polymer hydration, Differential Scanning Calorimetry, Infra-Red spectroscopy, X ray diffraction and mucoadhesive strength were determined. Polymer hydration was studied with respect to time, pH and ionic strength. HET-CAM test and Draize skin irritation test was performed to evaluate the degree of irritation caused by these polymers. Results and Discussion: It was found that as more hydrophobic groups were introduced in the polymer structure, hydration potential was reduced. The effect of concentration of crosslinking agent on bioadhesive strength was significant. With increase in density of crosslinking agent, the bioadhesive strength decreased. Polymers were found to be non-irritant to slight irritant in nature. Key words: Bioadhesion, Ocular, Water Insoluble polymer, Acrylic acid, Hydration.

An evaluation of the gliding performance of solid oral dosage form film coatings using an artificial mucous layer.

Oral drug delivery technology is mainly provided in the form of solid oral dosage forms (SODF) that have to be swallowed intact and move throughout the oro-esophageal system to release the drug content in the stomach or intestine. As there is growing evidence for an increasing prevalence of impaired swallowing functions in certain diseases, multimorbidity and advanced age, predictive in vitro methods for the oro-esophageal gliding behavior of SODF would be very useful. The gliding performance of different SODF polymer films was investigated across an artificial mucous layer using a versatile in vitro gliding system. In a first phase, the system measures the force required to move the polymer surface when placed in contact with the mucin layer and, in a second phase, the resistance behavior over a defined length. The obtained results showed that comprehensive gliding profiles could be obtained depending on the polymer film tested. The carnauba wax and PEG coatings required lower gliding peak forces and showed poor gliding resistance, which is indicative of free gliding capacity. In contrast, HPMC, PVP and gelatin coatings required higher gliding forces and exhibited greater resistance due to an adhesive interaction with the artificial mucous layer. The obtained profiles correlate with prior in vitro data during polymer gliding evaluations on mucosal membranes.

Characterization of a phospholipid-regulated β-galactosidase from Akkermansia muciniphila involved in mucin degradation.

The gut microbe Akkermansia muciniphila is important for the human health as the occurrence of the organism is inversely correlated with different metabolic disorders. The metabolism of the organism includes the degradation of intestinal mucins. Thus, the gut health‐promoting properties are not immediately obvious and mechanisms of bacteria‐host interactions are mostly unclear. In this study, we characterized a novel extracellular β‐galactosidase (Amuc_1686) with a preference for linkages from the type Galβ1–3GalNAc. Additionally, Amuc_1686 possesses a discoidin‐like domain, which enables the interaction with anionic phospholipids. We detected a strong inhibition by phosphatidylserine, phosphatidylglycerol, phosphatidic acid, and lysophosphatidic acid while phosphatidylcholine and phosphatidylethanolamine had no influence. Amuc_1686 is the first example of a prokaryotic hydrolase that is strongly inhibited by certain phospholipids. These inhibiting phospholipids have important signal functions in immune response and cell clearance processes. Hence, Amuc_1686 might be regulated based on the health status of the large intestine and could therefore contribute to the mutualistic relationship between the microbe and the host on a molecular level. In this sense, Amuc_1686 could act as an altruistic enzyme that does not attack the mucin layer of apoptotic epithelial cells to ensure tissue regeneration, for example, in areas with inflammatory damages.

Role of the Kaiso gene in the development of inflammation in Mucin-2 defcient mice

The number of people with inflammatory bowel disease (IBD) is constantly increasing worldwide. The main factors that have effects on the etiology of the disease are genetic, environmental and immunological. However, the mechanism of disease development and effective treatment of IBD have not yet been found. Animal models help address these problems. The most popular model is considered to be transgenic models in which individual genes are knocked out. One of such models for the study of IBD are mice with a null mutation of theMuc2gene encoding the Mucin-2 protein, which is involved in the formation of a protective mucin layer in the small and large intestine. Some of transcription factors that change the expression of intestinal genes are involved in the development of IBD and colorectal cancer. One of such transcription factors is “zinc fnger” domain-containing protein Kaiso which is able to bind to methylated DNA. In this study, we assessed the role of Kaiso in the development of intestinal inflammation using the experimental model of C57BL/6Muc2-/-Kaiso-/-. We have shown that mice with impaired intestinal barrier function that develop processes similar to human IBD also develop inflammatory responses, such as increased expression ofIl1,TnfandIl17agenes. The defciency of the Kaiso transcription factor in Mucin-2 knockout mice causes a decrease in the expression level of only theCox2andTff3genes. Perhaps a decline in the expression of the gene encoding cyclooxygenase-2 can lead to a decrease in the expression of the antibacterial factor Trefoil factor 3. However, in the experimental model of IBD, Kaiso protein did not play a signifcant role in the regulation of pro-inflammatory cytokines of tumor necrosis factor and interleukins 1 and 17.

The clinical profile and prevalence of dry eye in tertiary care hospital- based population

Background: Dry eye is recognized as a growing public health problem and one of the most frequent reasons for visiting an ophthalmologist in middle and old age people. Objectives: To the best of our knowledge, very less study has been undertaken in central India on dry eye. The present study was designed to study clinical profile and to evaluate the true prevalence and risk factors of dry eye in central India. Materials and Methods: A total of 1562 participants aged 30 years or more visiting ophthalmology department in a tertiary care rural hospital enrolled in a study. Study duration was 18 months. The study design was a prospective, cross-sectional, and observational study. An ocular surface disease index (OSDI) questionnaire was administered to all participants and individuals with OSDI score greater than 12 were further evaluated with dry eye tests in sequence of tear break-up time, lissamine green staining, Schirmer-1 test, and slit-lamp examination for meibomian gland dysfunction. The participants with OSDI Score ≥13 were diagnosed to be having dry eye. The data were compiled and subjected to statistical analysis using SPSS v.17.0 software (SPSS Inc., Chicago, Illinois, USA). P < 0.05 was considered to be statistically significant. Results: Prevalence of dry eye in our study was 24.7%. Prevalence of lipid layer, aqueous layer, and mucin layer deficiency dry eye was 13.8%, 5.2%, and 7.8%, respectively. Increasing age, illiteracy, and menopause were the significant risk factors and female sex, urban habitat, and laborer and factory worker were insignificant risk factors for dry eye. Conclusion: Prevalence of dry eye in our study is higher than reported in literature in central India. Lipid anomaly dry eye was the most prevalent, followed by mucin layer deficiency and lastly aqueous tear deficiency.

Shear-Enhanced Dynamic Adhesion of Lactobacillus rhamnosus GG on Intestinal Epithelia: Correlative Effect of Protein Expression and Interface Mechanics.

The oral uptake of probiotic microorganisms as food additives is one widely used strategy to sustain and improve the homeostasis of intestinal microbiota that protect the intestinal epithelia from attack by pathogenic bacteria. Once delivered to the ileum and colon, probiotics must adhere and form colonies on mucus that coats the surface of intestinal epithelial cells. Although an increasing amount of knowledge about the genetic and molecular level mechanisms of probiotics-mucus interactions has been accumulated, little is known about the physicochemical aspects of probiotics-mucus interactions under physiological shear in intestines. In this study, we established well-defined models of intestinal epithelial cell monolayers based on two major constituents of gut epithelia, enterocytes and goblet cells. First, the formation of a polarized cell monolayer sealed by tight junctions was monitored by transepithelial electrical resistance over time. The establishment of tight junctions and secretion of mucus proteins (mucin) was confirmed by immunofluorescence staining. In the next step, we measured the elasticity of cell monolayer surfaces by indentation using particle-assisted atomic force microscopy. The effective elastic modulus of goblet cell-like cells was 30 times smaller compared to that of enterocyte-like cells, which can be attributed to the secretion of a 3 μm thick mucin layer. As probiotics, we used Lactobacillus rhamnosus GG (LGG), which is one of the most widely used strains as food additives. To investigate the dynamic adhesion of LGG to the intestine model surface, we transferred the epithelial cell monolayer into a microfluidic chamber. A distinct difference in dynamic adhesion between two cell types was observed, which could be attributed to the difference in the mucin expression amount. Remarkably, we found that the dynamic LGG adhesion is enhanced by the increase in shear stress, showing a maximum binding efficiency at 0.3 Pa. Finally, we examined the persistence of LGG adhesion by a stepwise increase in the shear stress exerted on adherent LGG, demonstrating that LGG could withstand high shear stress even beyond that of physiological stress. The obtained results present a large potential to quantitatively understand the influence of engineered foods and probiotics on the homeostasis of microbiota on the surface of intestinal epithelia.

Short Tear Film Breakup Time-Type Dry Eye.

Measurement of tear film breakup time (TBUT) has become a standard diagnostic procedure in the dry eye clinic. Short TBUT-type dry eye is characterized by TBUT of less than 5 seconds and dry eye symptoms such as ocular fatigue or dryness; the importance of this type has recently been gaining prominence. Patients with this condition show no reduction in tear production and no staining of the ocular surface. The severity of symptoms is almost the same as in dry eye in which the ocular surface is stained with rose bengal or fluorescein. In addition to discomfort, patients suffer from decreased vision due to the unstable tear film, which can be attributed to the relative abnormality of the lipid layer, aqueous layer, and/or mucin layer. The diagnosis should be performed carefully on the basis of the patient's symptoms and the TBUT test, because the ocular surface appears normal and remains unstained.

Reconsidering the central role of mucins in dry eye and ocular surface diseases.

Mucins are key actors in tear film quality and tear film stability. Alteration of membrane-bound mucin expression on corneal and conjunctival epithelial cells and/or gel-forming mucin secretion by goblet cells (GCs) promotes in ocular surface diseases and dry eye disease (DED). Changes in the mucin layer may lead to enhanced tear evaporation eventually contributing to tear hyperosmolarity which has been associated with ocular surface inflammation. Inflammatory mediators in turn may have a negative impact on GCs differentiation, proliferation, and mucin secretion. This sheds new light on the position of GCs in the vicious circle of DED. As contributor to ocular surface immune homeostasis, GC loss may contribute to impaired ocular surface immune tolerance observed in DED. In spite of this, there are no tools in routine clinical practice for exploring ocular surface mucin deficiency/dysregulation. Therefore, when selecting the most appropriate treatment options, there is a clear unmet need for a better understanding of the importance of mucins and options for their replacement. Here, we comprehensively revisited the current knowledge on ocular surface mucin biology, including functions, synthesis, and secretion as well as the available diagnostic tools and treatment options to improve mucin-associated homeostasis. In particular, we detailed the potential link between mucin dysfunction and inflammation as part of the uncontrolled chronic inflammation which perpetuates the vicious circle in DED.