Production and secretion of transforming growth factor beta (TGF-beta) by the human lacrimal gland

Ocular Surface Health in Connection with Anxiety and Depression: a Review

Psychosomatic ophthalmology emerged after World War II because patients attended clinics with symptoms that were not explained by physiological findings, subsequently it became clear that psychological distress could be associated with several ocular disorders, including dry eye syndrome. Dry eye disease is a common disorder with increasing prevalence due to environmental factors such as pollution, smoking, and sleep disorders. The burden of dry eye disease affects both patients and society, making it a very important target for investigation. Numerous studies showed that dry eye disease prevalence including the severity of the symptoms of dry eye is higher in patients suffering from depression and/or anxiety. Some studies suggest the implication of serotonin in tears being dysregulated by the disorders. The current review highlights the evidence of the association between anxiety, depression, and dry eye disease and summarizes the recent advances in research in this area, together with a brief explanation of the physiology of stress that could lead to psychological disorders.

[Cell technologies as a basis for the development of regenerative principles for the treatment of lacrimal gland diseases]

The lacrimal gland (LG) is a tubuloacinar exocrine gland composed of acinar, ductal, and myoepithelial cells. Three-dimensional distribution of acinar lobules, ducts, and myoepithelial cells is necessary for the effective functioning of the organ. LG is the main organ of immune surveillance of the ocular surface system. The embryogenesis of the gland is regulated by the interaction of genetic mechanisms, internal epigenetic (enzyme systems, hormones) and exogenous factors. There is no doubt that there is a clear genetic program for the implementation of the complex process of embryonic development. The mechanisms regulating LG organogenesis initiate the work of a huge number of structural oncogenes, transcription and growth factors, etc. Studying the expression and selective activity of regulatory genes during organ development, their participation in the differentiation of different cell types is a current trend at the nexus of clinical genetics, molecular biology, embryology and immunocytochemistry. Due to its relatively simple structure and accessibility, human LG is a suitable object for potential application in regenerative medicine. Development of a universal protocol for obtaining functional differentiated secretory epithelium of LG capable of expressing tissue-specific markers is an urgent task. Determining the nature and origin of stem cells and progenitor cells will allow the isolation and multiplication of these cells in culture. After obtaining a functionally active culture of LG cells, it is possible to create a model of autoimmune diseases.

Treatment of Severe Dry Eye in Stevens-Johnson Syndrome with Umbilical Cord Serum Eye Drops

PURPOSE

To evaluate the efficacy and safety of umbilical cord serum eye drops for dry eyes in ocular Stevens-Johnson Syndrome (SJS).

PATIENTS AND METHODS

A pre-post test study with umbilical cord serum (UCS) eye drop for ocular SJS patient with moderate to severe dry eyes. Study was conducted at Kirana Cipto Mangunkusumo General Hospital from June 2020 to December 2020. A total of five patients (five eyes) with a diagnosis of SJS more than 6 months, dry eye symptoms, and abnormal tear stability test results were included in the study. Each patient was asked to instill UCS drop into the affected eye six times daily. Evaluation of ocular symptoms with ocular surface disease index (OSDI) questionnaires, non-invasive tear break-up time (NIBUT), Schirmer I, and keratoepitheliopathy scores was administered before applying UCS drop and at week 2 and 4 of eye drop use.

RESULTS

From June 2020 to December 2020, five eyes of five patients were evaluated in this study. Patients were aged from 22 to 71 years old with history of SJS over periods from 1 to 35 years. Three patients underwent ocular surgeries prior to the study. After four weeks of treatment, symptoms score, Schirmer I, and keratoepitheliopathy scores improved significantly, while NIBUT scores improved insignificantly. No side effects were noted during treatment.

CONCLUSION

Administration of UCS eye drop was effective in improving symptoms and signs of dry eye in chronic SJS patients.

Autologous versus allogeneic versus umbilical cord sera for the treatment of severe dry eye disease: a double-blind randomized clinical trial

PURPOSE

To measure the effects of Autologous serum (AS), Allogeneic Serum (HS) and Umbilical Cord serum (CS) eye drops in severe dry eye disease (DES), as well as to characterize and quantify several molecules in the three sera (albumin, fibronectin; Vitamin A and E; IgG, IgA and IgM; Transforming growth factor β; Epithelial growth factor).

METHODS

Randomized, double-blind, single-centre, three-arm (AS, HS and CS) clinical trial. Sixty-three subjects were included with severe DES, 21 in each arm of the study. Visual acuity, Schirmer test, Breakup time (BUT), lissamine green, fluorescein staining measurements and a questionnaire were performed prior to treatment, and after one-month and three-month follow-up.

RESULTS

There was a significant main effect of time on visual acuities, Schirmer and BUT tests and fluorescein and lissamine green staining measurements and questionnaire scores (p = 0.015, p = 0.002, p < 0.001, p < 0.001, p = 0.031 and p < 0.001, respectively), although there was no significant interaction between time and serum type, nor between serum type and the test performed. Regarding the concentration of molecules, in our study AS contained significantly higher concentrations of IgA, IgG and fibronectin whereas HS contained significantly higher concentration of IgM, vitamins A and E, TGF and albumin. Contrary to previous reports, CS did not show higher concentration of any of the molecules analysed.

CONCLUSIONS AND RELEVANCE

The three sera were effective in the treatment of severe DES. CS did not contain a higher proportion of molecules compared to AS/HS. More research is needed to assess the effect of AS in patients with DES and autoimmune diseases.

TGFβ1 and TGFβ2 proteins in corneas with and without stromal fibrosis: Delayed regeneration of apical epithelial growth factor barrier and the epithelial basement membrane in corneas with stromal fibrosis

The purpose of this study was to investigate the expression and localization of transforming growth factor (TGF) β1 and TGFβ2 in rabbit corneas that healed with and without stromal fibrosis, and to further study defective perlecan incorporation in the epithelial basement membrane (EBM) in corneas with scarring fibrosis. A total of 120 female rabbits had no surgery, -4.5D PRK, or -9D PRK. Immunohistochemistry (IHC) was performed at time points from unwounded to eight weeks after surgery, with four corneas at each time point in each group. Multiplex IHC was performed for TGFβ1 or TGFβ2, with Image-J quantitation, and keratocan, vimentin, alpha-smooth muscle actin (SMA), perlecan, laminin-alpha 5, nidogen-1 or CD11b. Corneas at the four-week peak for myofibroblast and fibrosis development were evaluated using Imaris 3D analysis. Delayed regeneration of both an apical epithelial growth factor barrier and EBM barrier function, including defective EBM perlecan incorporation, was greater in high injury -9D PRK corneas compared to -4.5D PRK corneas without fibrosis. Defective apical epithelial growth factor barrier and EBM allowed epithelial and tear TGFβ1 and tear TGFβ2 to enter the corneal stroma to drive myofibroblast generation in the anterior stroma from vimentin-positive corneal fibroblasts, and likely fibrocytes. Vimentin-positive cells and unidentified vimentin-negative, CD11b-negative cells also produce TGFβ1 and/or TGFβ2 in the stroma in some corneas. TGFβ1 and TGFβ2 were at higher levels in the anterior stroma in the weeks preceding myofibroblast development in the -9D group. All -9D corneas (beginning two to three weeks after surgery), and four -4.5D PRK corneas developed significant SMA + myofibroblasts and stromal fibrosis. Both the apical epithelial growth factor barrier and/or EBM barrier functions tended to regenerate weeks earlier in -4.5D PRK corneas without fibrosis, compared to -4.5D or -9D PRK corneas with fibrosis. SMA-positive myofibroblasts were markedly reduced in most corneas by eight weeks after surgery. The apical epithelial growth factor barrier and EBM barrier limit TGFβ1 and TGFβ2 entry into the corneal stroma to modulate corneal fibroblast and myofibroblast development associated with scarring stromal fibrosis. Delayed regeneration of these barriers in corneas with more severe injuries promotes myofibroblast development, prolongs myofibroblast viability and triggers stromal scarring fibrosis.

Comparison of the Levels of Transforming Growth Factor-β1 in Tear Fluid in Patients with High Myopia after Transepithelial Photorefractive Keratectomy and Laser Subepithelial Keratomileusis (LASEK)

We compared the level of transforming growth factor-β1 (TGF-β1) in the tear fluid of 20 patients with high myopia who underwent transepithelial photorefractive keratectomy (T-PRK) in one eye and laser subepithelial keratomileusis (LASEK) in the contralateral eye. Tear fluid samples were collected with scaled microcapillary tubes before (day 0) and on days 1, 3, and 5 after surgery. The release of TGF-β1 was determined by multiplying the concentration of TGF-β1 by capillary tear fluid flow. Corneal haze was also evaluated in 1, 3, and 6 months after surgeries. The median TGF-β1 release after T-PRK and LASEK differed significantly on days 1 and 3 (p<0.005) and on day 5 (p<0.05). The mean corneal haze score after T-PRK and LASEK also significantly differed in 1 month (p<0.005), but no significant differences in this parameter were revealed at later terms. Thus, the level of TGF-β1 in the tear fluid after T-PRK was lower than after LASEK, which can be the cause of less pronounced corneal haze in 1 month after surgery.

Biological functions of tear film

Tears have a vital function to protect and lubricate the ocular surface. Tear production, distribution and clearance is tightly regulated by the lacrimal functional unit (LFU) to meet ocular surface demands. The tear film consists of an aqueous-mucin layer, containing fluid and soluble factors produced by the lacrimal glands and mucin secreted by the goblet cells, that is covered by a lipid layer. The array of proteins, glycoproteins and lipids in tears function to maintain a stable, well-lubricated and smooth optical surface. Tear factors also promote wound healing, suppress inflammation, scavenge free radicals, and defend against microbial infection. Disease and dysfunction of the LFU leads to tear instability, increased evaporation, inflammation, and blurred and fluctuating vision. The function of tear components and the consequences of tear deficiency on the ocular surface are reviewed.

Goblet cell-produced retinoic acid suppresses CD86 expression and IL-12 production in bone marrow-derived cells

Conjunctival goblet cell loss in ocular surface diseases is accompanied by increased number of interleukin-12 (IL-12)-producing antigen-presenting cells (APCs) and increased interferon-γ (IFN-γ) expression. This study tested the hypothesis that mouse conjunctival goblet cells produce biologically active retinoic acid (RA) that suppresses CD86 expression and IL-12 production by myeloid cells. We found that conditioned media from cultured conjunctival goblet cells (CjCM) suppressed stimulated CD86 expression, NF-κB p65 activation and IL-12 and IFN-γ production in unstimulated and lipopolysaccharide-stimulated cultured bone marrow-derived cells (BMDCs) containing a mixed population of APCs. Goblet cell-conditioned, ovalbumin-loaded APCs suppressed IFN-γ production and increased IL-13 production in co-cultured OTII cells. The goblet cell suppressive activity is due in part to their ability to synthesize RA from retinol. Conjunctival goblet cells had greater expression of aldehyde dehydrogenases Aldh1a1 and a3 and ALDEFLUOR activity than cornea epithelium lacking goblet cells. The conditioning activity was lost in goblet cells treated with an ALDH inhibitor, and a retinoid receptor alpha antagonist blocked the suppressive effects of CjCM on IL-12 production. Similar to RA, CjCM increased expression of suppressor of cytokine signaling 3 (SOCS3) in BMDCs. SOCS3 silencing reversed the IL-12-suppressive effects of CjCM. Our findings indicate that conjunctival goblet cells are capable of synthesizing RA from retinol secreted by the lacrimal gland into tears that can condition APCs. Evidence suggests goblet cell RA may function in maintaining conjunctival immune tolerance and loss of conjunctival goblet cells may contribute to increased Th1 priming in dry eye.

Age- and sex-associated changes in prosaposin and its receptors in the lacrimal glands of rats

Prosaposin, a saposin precursor, is a potent neurotrophic factor found in several tissues and various biological fluids. Saposin-deficient patients have different ophthalmic disorders, indicating a relationship between ocular health and prosaposin. However, there is little information about prosaposin on the ocular surface. Because ocular functions are diverse and depend on age and sex, we examined whether prosaposin and its receptors, G protein-coupled receptor 37 (GPR37) and GPR37L1, are expressed in the major ocular glands, the extra orbital lacrimal gland (ELG), and harderian gland (HG) of rats and whether sex and aging affect their expression. Immunohistochemical analyses revealed that prosaposin and its receptors were expressed in the ELGs and HGs of rats, although their expression varied based on the type of gland, age, and sex. Prosaposin, GPR37, and GPR37L1 were expressed in the basolateral membranes and cytoplasm of acinar cells of the ELGs, and their immunoreactivities were higher in female rats of menopausal age than age-matched male rats. However, such age- and sex-related differences in the immunoreactivities of prosaposin, GPR37, and GPR37L1 were not observed in the HGs. Triple immunofluorescence labelling revealed that prosaposin, GPR37, and GPR37L1 were co-localised in the acinar and ductal cells in the ELGs, although the degrees of colocalization varied according to the age and sex of the rats. Together, the present results showed that prosaposin and its receptors were expressed in the major ocular glands of rats, and their immunoreactivities to the ELGs differed considerably with age and sex.

Review: The Lacrimal Gland and Its Role in Dry Eye

The human tear film is a 3-layered coating of the surface of the eye and a loss, or reduction, in any layer of this film may result in a syndrome of blurry vision and burning pain of the eyes known as dry eye. The lacrimal gland and accessory glands provide multiple components to the tear film, most notably the aqueous. Dysfunction of these glands results in the loss of aqueous and other products required in ocular surface maintenance and health resulting in dry eye and the potential for significant surface pathology. In this paper, we have reviewed products of the lacrimal gland, diseases known to affect the gland, and historical and emerging dry eye therapies targeting lacrimal gland dysfunction.

Effects of azithromycin on gene expression profiles of proinflammatory and anti-inflammatory mediators in the eyelid margin and conjunctiva of patients with meibomian gland disease

IMPORTANCE

Topical application of azithromycin suppresses expression of proinflammatory mediators while restoring transforming growth factor β1 (TGF-β1) levels as evaluated by eyelid margin and conjunctival impression cytology.

OBJECTIVE

To explore the effects of azithromycin therapy on expression of proinflammatory and anti-inflammatory mediators in meibomian gland disease (MGD).

DESIGN, SETTING, AND PARTICIPANTS

Case-control study performed in a clinic setting from August 17, 2010, to December 31, 2010. Sixteen patients with posterior blepharitis and conjunctival inflammation due to MGD were treated with azithromycin, 1%, drops for 4 weeks. Impression cytology of the lower eyelid margin and tarsal conjunctiva to measure cytokine expression by quantitative real-time polymerase chain reaction as well as tear collection to measure matrix metalloproteinase 9 (MMP-9) activity were performed once in 8 asymptomatic healthy control participants and 5 times in the 16 symptomatic patients (every 2 weeks for 8 weeks), before, during, and after azithromycin treatment.

EXPOSURE

Azithromycin, 1%, drops for 4 weeks.

MAIN OUTCOMES AND MEASURES

Cytokine expression in the eyelid margin and conjunctiva, and MMP-9 activity in tears.

RESULTS

Compared with a 1-time measurement of 8 healthy participants, among 16 symptomatic patients, the mean (SD; 95% CI) fold change of expression of proinflammatory mediators interleukin 1β (IL-1β), IL-8, and MMP-9 increased to 13.26 (4.33; 11.14-15.38; P < .001), 9.38 (3.37; 7.73-11.03; P < .001), and 13.49 (4.92; 11.08-15.90; P < .001), respectively, in conjunctival cells and to 11.75 (3.96; 9.81-13.69; P < .001), 9.31 (3.28; 7.70-10.92; P < .001), and 11.52 (3.50; 9.81-13.24; P < .001), respectively, in the eyelid margin of patients with MGD. In contrast, the mean (SD; 96% CI) fold change of expression of TGF-β1 messenger RNA (mRNA) decreased to 0.58 (0.25; 0.46-0.70; P = .02) and 0.63 (0.14; 0.56-0.70; P = .02) in conjunctival and eyelid margin cells, respectively, of patients with MGD. Azithromycin, 1%, caused a change in the expression pattern of these mediators toward normal levels during 4 weeks of treatment. Levels of IL-1β, IL-8, and MMP-9 mRNA remained suppressed, although they rebounded toward pretreatment values 4 weeks after azithromycin withdrawal. Expression of TGF-β1 increased during treatment and remained at levels similar to the healthy controls after drug withdrawal. Change in tear MMP-9 activity was similar to the pattern of MMP-9 transcripts.

CONCLUSIONS AND RELEVANCE

While the study did not control for potential confounding factors over time independent of the intervention that may have contributed to the results, topical azithromycin suppressed expression of proinflammatory mediators and increased expression of TGF-β1 to normal levels. Increased TGF-β1 expression may contribute to the anti-inflammatory activity of azithromycin in MGD.

Human Serum Eye Drops in Eye Alterations: An Insight and a Critical Analysis

Human serum contains a physiological plethora of bioactive elements naturally released by activated platelets which might have a significant effect on the regeneration of corneal layers by stimulating the cell growth. This mechanism supported the use of human serum eye drops in some ocular diseases associated with dystrophic changes and alterations of the tear film, such as persistent corneal epithelial defects and dry eye syndrome. We focused our effort on potential benefits and limitations of the use of human serum eye drops when conventional therapies failed. We reviewed the recent literature by reporting published studies from 2010 to 2014. Despite the limited evaluated study populations, most of the clinical studies have confirmed that serum eye drop therapy is effective in corneal healing by reducing ocular symptom, particularly during the short-term follow-up. In addition, three recent published studies have shown the efficacy of the serum eye drop therapy in comparison to traditional ones in intractable patients. Besides, reported ongoing clinical studies confirmed the open debate regarding the use of biologic tools for cornea regeneration. Results from these studies might open novel challenges and perspectives in the therapy of such refractory patients.

Ocular Mucosal Immunity

Mucosal immunity defends the ocular surface against antigenic challenge and microbial invasion. The principal effector site is the lacrimal gland, where immunoglobulin A (IgA) antibodies are produced. Nasal-associated lymphoid tissue and posterior cervical lymph nodes function as major inductive sites for tear IgA responses. Neural connections and systemic hormones maintain the integrity and function of the ocular surface. Neuroenzyme activities in the lacrimal gland are influenced by ocular infections, leading to reduced expression of acetylcholine and modulation of receptors on acinar cells and on plasma cells, thereby decreasing fluid and immunoglobulin secretion. T lymphocyte-dependent responses result in production of interleukin-4 in lacrimal glands, thereby influencing cholinergic enzyme activity affecting immune processes and lacrimal physiology. Furthermore, neuropeptides released into lymphoid structures or inflamed tissues are chemotactic for antigen-presenting cells and affect their interactions with T cells. Thus, in developing therapeutic approaches for treating dry-eye conditions and vaccination strategies to elicit protective ocular mucosal immune responses, the entire lacrimal functional unit should be considered.

[Treatment of corneal ulcers with platelet rich plasma]

OBJECTIVE

To assess the efficacy of platelet rich plasma (PRP) in the treatment of extensive corneal ulcers in albino rabbits.

METHODS

New Zealand rabbits, divided in 3 groups, were used for the study. Corneal ulcers of 10mm diameter were made. Rabbits blood was extracted for the preparation of the PRP of the corresponding group. The blood was processed by differential centrifugation. The first group, named control, was treated with sterile saline every 8h. The second group, named gel, was treated with deproteinized extract gel beef fat every 8h, and the third group, named PRP received one PRP drop on the first and third day of monitoring. The rabbits were monitored, by taking photographs, each day for the 7 days that the study lasted.

RESULTS

A better outcome was observed in the group with deproteinized extract gel beef fat (GE group), and the PRP group (PL group), in comparison with the control group (CO group) (P<.05).

CONCLUSION

The PRP showed to be just as effective as the commercial product (Solcoseryl®), for the regeneration of the extensive and deep corneal ulcers. Besides, it stands out as a no surgical procedure is required, and there is easy access, low cost and reduced doses.

Dendritic cell-derived thrombospondin-1 is critical for the generation of the ocular surface Th17 response to desiccating stress

TSP-1 is a physiologic activator of TGF-β, a critical induction factor for Th17-mediated immunity. The purpose of this study was to investigate the role of TSP-1 in the induction of the Th17 ocular surface response to DS. TSP-1KO and WT mice were subjected to DS5 and DS10), and parameters of ocular surface disease, including corneal barrier function, conjunctival CD4(+) T cell infiltration, and GC density, were evaluated. TSP-1KO mice subjected to DS had less corneal barrier disruption, reduced loss of PAS+ GC, and decreased CD4(+) T cell infiltration in the conjunctiva. In contrast to WT, TSP-1KO mice failed to up-regulate MMP-3 and MMP-9 mRNA transcripts in the cornea and IL-17A mRNA transcripts in the conjunctiva. RAG-1KO recipients of adoptively transferred CD4(+) T cells isolated from TSP-1KO mice subjected to DS5 showed milder dry-eye phenotype and less conjunctival inflammation than recipients of CD4(+) T cells from DS5 WT control. Reconstitution of TSP-1KO mice with WT DCs prior to DS reversed the resistance of the TSP-1KO to DS-induced immunopathology. In conclusion, DC-derived TSP-1 is critical for generating the Th17 ocular surface response to DS.

Immunohistofluorescence analysis of myofibroblast transdifferentiation in human corneas with bullous keratopathy

PURPOSE

To detect the transdifferentiation of keratocytes into myofibroblasts in human corneas with bullous keratopathy and to examine the relation of such transdifferentiation to the clinical course of the disease.

METHODS

Twenty patients with bullous keratopathy who underwent penetrating keratoplasty were enrolled in the study. Corneal buttons collected during surgery were examined for expression of α-smooth muscle actin (αSMA) by immunoblot analysis and by immunofluorescence analysis of whole-mount preparations. The course of bullous keratopathy was evaluated from clinical charts.

RESULTS

Immunoblot analysis revealed a marked increase in αSMA expression in some corneas affected by bullous keratopathy. Immunofluorescence analysis revealed that αSMA was expressed in myofibroblastic cells in the stroma of 10 of the 20 corneas examined. Expression of αSMA was detected in subjects with a clinical history of corneal epithelial erosion from 12 months after the onset of clinical stromal edema. In contrast, in subjects without a clinical history of epithelial erosion, αSMA expression was not detected until at least 27 months after the onset of stromal edema. The incidence of αSMA expression in stromal cells was not significantly associated with topical steroid administration.

CONCLUSIONS

Transdifferentiation of keratocytes into myofibroblasts was observed in human corneas affected by bullous keratopathy. Such transdifferentiation occurred earlier after the onset of stromal edema in patients with a clinical history of epithelial erosion than in those without such a history.

Disruption of TGF-β signaling improves ocular surface epithelial disease in experimental autoimmune keratoconjunctivitis sicca

BACKGROUND

TGF-β is a pleiotropic cytokine that can have pro- or anti-inflammatory effects depending on the context. Elevated levels of bioactive TGF-β1 in tears and elevated TGF-β1mRNA transcripts in conjunctiva and minor salivary glands of human Sjögren's Syndrome patients has also been reported. The purpose of this study was to evaluate the response to desiccating stress (DS), an experimental model of dry eye, in dominant-negative TGF-β type II receptor (CD4-DNTGFβRII) mice. These mice have a truncated TGF-β receptor in CD4(+) T cells, rendering them unresponsive to TGF-β.

METHODOLOGY/PRINCIPAL FINDINGS

DS was induced by subcutaneous injection of scopolamine and exposure to a drafty low humidity environment in CD4-DNTGFβRII and wild-type (WT) mice, aged 14 weeks, for 5 days. Nonstressed (NS) mice served as controls. Parameters of ocular surface disease included corneal smoothness, corneal barrier function and conjunctival goblet cell density. NS CD4-DNTGFβRII at 14 weeks of age mice exhibited a spontaneous dry eye phenotype; however, DS improved their corneal barrier function and corneal surface irregularity, increased their number of PAS+ GC, and lowered CD4(+) T cell infiltration in conjunctiva. In contrast to WT, CD4-DNTGFβRII mice did not generate a Th-17 and Th-1 response, and they failed to upregulate MMP-9, IL-23, IL-17A, RORγT, IFN-γ and T-bet mRNA transcripts in conjunctiva. RAG1KO recipients of adoptively transferred CD4+T cells isolated from DS5 CD4-DNTGFβRII showed milder dry eye phenotype and less conjunctival inflammation than recipients of WT control.

CONCLUSIONS/SIGNIFICANCE

Our results showed that disruption of TGF-β signaling in CD4(+) T cells causes paradoxical improvement of dry eye disease in mice subjected to desiccating stress.

Evaluation of the transforming growth factor-beta activity in normal and dry eye human tears by CCL-185 cell bioassay

PURPOSE

To develop a new bioassay method using human lung epithelial cells (CCL-185) to assess activity of transforming growth factor beta (TGF-beta) in human tear fluid from normal subjects and patients with dry eye.

METHODS

Two epithelial cell lines, mink lung cells (CCL-64) and human lung cells (CCL-185), were compared to detect the active form of TGF-beta by BrdU incorporation (quantitation of cell DNA synthesis) and WST assay (metabolic activity of viable cells). The effect of TGF-beta on the growth of CCL-185 cells was observed microscopically. Human tears from normal control subjects and patients with dry eye (DE) with and without Sjögren syndrome were evaluated for TGF-beta concentration by Luminex microbead assay, and TGF-beta activity by the CCL-185 cell growth inhibition bioassay.

RESULTS

The metabolic activity of viable CCL-185 cells, measured by WST, was shown to be proportional to the TGF-beta1 concentration (R = 0.919) and confirmed by BrdU assay (R = 0.969). Compared with CCL-185, metabolic activity of viable cells and DNA synthesis, measured by WST and BrdU incorporation assays, were shown to be less proportional to the TGF-beta1 concentration in the CCL-64 line (R = 0.42 and 0.17, respectively). Coincubation with human anti-TGF-beta1 antibody (MAB-240) yielded a dose-dependent inhibition of TGF-beta1 (0.3 ng/mL) activity. CCL-185 cell growth observed microscopically was noted to decrease in response to increasing TGF-beta1 concentrations. Levels of immuodetectable TGF-beta1 and TGF-beta2 were similar in normal and DE tears. TGF-beta bioactivity in DE human tears measured by the CCL-185 cells assay was found to be higher (9777.5 +/- 10481.9 pg/mL) than those in normal controls (4129.3 +/- 1342.9 pg/mL) (P < 0.05). Among patients with DE, TGF-beta bioactivity was highest in those with Sjögren syndrome. Approximately, 79.1% of TGF-beta in DE tears and 37.6% TGF-beta in normal tears were found to be biologically active.

CONCLUSIONS

The CCL-185 cell assay was found to be a suitable tool for assessing TGF-beta activity in human tears. Tear TGF-beta bioactivity increases in DE, particularly in Sjögren syndrome, where elevated levels of TGF-beta1 transcripts in the conjunctival epithelium have been previously detected.

Influence of bilateral medial collateral ligament injury on mRNA expression in distal corneal tissues of control and ovariohysterectomized rabbits

PURPOSE

Corneal tissues are reported to be impacted by physiological changes (eg, menopause), systemic autoimmune diseases, and osteoarthritic-like conditions. In this study, changes in specific mRNA levels in the cornea after a ligament injury in normal and rabbits subjected to surgical menopause were examined.

METHODS

Skeletally mature female rabbits were either sham-operated (control) or were subjected to surgical menopause (OVX). Eight weeks post-OVX, subsets of control and OVX animals were subjected to bilateral injuries to their medial collateral ligaments (MCL) of the knee, and 6 and 14 weeks postinjury, corneal tissues were harvested. Using reverse transcriptase-polymerase chain reaction, mRNA levels for several relevant molecules, including matrix molecules, growth factors, cytokines, proteinases, and hormone receptors, were assessed.

RESULTS

mRNA levels for estrogen receptor, decorin, collagens, several growth factors, and inflammatory cytokines decreased in central corneal tissue 6 weeks after distal MCL injury in control animals. The central corneal tissues of animals subjected to OVX alone also exhibited decreases in mRNA levels for a similar set of molecules. When OVX animals were further subjected to MCL injury, the mRNA levels for many of these molecules did not vary from those in the uninjured OVX group. Interestingly, mRNA levels for most molecules were still altered 14 weeks post-MCL injury in the control and OVX animals, a time when the MCL has healed.

CONCLUSIONS

Corneal tissues respond to changes resulting from OVX and/or injury. OVX combined with a ligament injury does not appear to have an additive impact on corneal mRNA levels for most of the molecules assessed.

Age-related T-cell cytokine profile parallels corneal disease severity in Sjogren's syndrome-like keratoconjunctivitis sicca in CD25KO mice

OBJECTIVES

IL-2ralpha (CD25)(-/-) mice develop autoimmunity and lymphoproliferative disorders, including SS-like disease. The objective of this study was to evaluate the severity of corneal epithelial disease and T-cell cytokine profile in the ocular surface tissues of CD25KO mice.

METHODS

CD25KO mice were evaluated at 8, 12 and 16 weeks of age. Corneal epithelial smoothness and corneal permeability were measured. Phenotype of infiltrating lymphocytes was evaluated by immunohistochemistry. Th-1, -2 and -17 associated factors were measured by real-time PCR in cornea and conjunctiva and by Luminex immunobead assay in tears.

RESULTS

Compared with 8-week-old wild-type (WT) mice, CD25KO mice of the same age had significantly greater corneal irregularity and a significant increase in the number of CD4(+) and CD8(+) T cells infiltrating the conjunctiva. CD25KO mice had significantly higher levels of IL-6, TGF-beta1, IL-23R, IL-17A, IL-17F, IL-21, CCL20, IL-10, GATA-3 and IFN-gamma mRNA transcripts in their cornea and conjunctiva than WT mice at 8 weeks. IL-17A and IL-17F mRNA transcripts peaked at 12 weeks, whereas IFN-gamma spiked at 16 weeks in CD25KO mice. Increased expression of IL-17A and IL-17F at 12 weeks in CD25KO mice was accompanied by a worsening of corneal surface parameters and an increase of CD4(+) T cell infiltrating the cornea.

CONCLUSIONS

Disruption of IL-2 signalling in CD25KO mice results in age-dependent SS-like autoimmune lacrimal-keratoconjunctivitis. A mix of Th-1 and Th-17 cytokines was detected. The peak severity of corneal epithelial disease corresponded to the peak of IL-17 expression.

Suppression of lymphocyte proliferation and regulation of dendritic cell phenotype by soluble mediators from rat lacrimal epithelial cells

Lacrimal epithelial cells appear to constitutively secrete autoantigens to their underling stroma. The present experiments address the hypothesis that they also secrete soluble factors that regulate immune responses. Epithelial cells, spleen cells and lymphocytes were obtained from rabbits or rats and cultured in various configurations. Monocytes from rat bone marrow were matured to dendritic cells (DC) ex vivo. Proliferation was measured by [3H]-thymidine incorporation; surface MHC Class II and CD86 using flow cytometry; and mRNA relative abundances using real time RT-PCR. Microporous culture inserts containing rat lacrimal cells inhibited proliferation of rabbit lymphocytes co-cultured with autologous lacrimal cells and of rat lymphocytes co-cultured with TNF-alpha-stimulated DC. They inhibited CD86 and MHC Class II surface expression by maturating DC and reversed surface expression of CD86 but not MHC Class II by partially matured DC. Subsequent exposure of partially matured DC to mediators from rat lacrimal cells reversed the ability to stimulate lymphocyte proliferation. TGF-beta(1) and IL-10 mRNAs increased somewhat when rat lacrimal cells were isolated but decreased markedly in rabbit lacrimal cells. Antibodies to TGF-beta prevented soluble factors from rat lacrimal cells from inhibiting proliferation of rabbit lymphocytes co-cultured with rabbit lacrimal cells, but recombinant TGF-beta alone did not mimic the soluble factors. IL-10 immunopositivity was detected in epithelial cells of interlobular ducts and occasional interstitial cells in rabbit lacrimal gland. Rat lacrimal epithelial cells secrete TGF-beta and other factors that synergize to suppress lymphocyte proliferation and regulate DC maturation. Interlobular duct epithelial cells in rabbit lacrimal glands may express similar functions.

Trehalose protects against ocular surface disorders in experimental murine dry eye through suppression of apoptosis

The disaccharide trehalose is a key element involved in anhydrobiosis (the capability of surviving almost complete dehydration) in many organisms. Its presence also confers resistance to desiccation and high osmolarity in bacterial and human cells by protecting proteins and membranes from denaturation. The present study used a novel murine dry eye model induced by controlled low-humidity air velocity to determine whether topically applied trehalose could heal ocular surface epithelial disorders caused by ocular surface desiccation. In addition, the efficacy of 87.6 mM trehalose eyedrops was compared with that of 20% serum, the efficacy of which has been well documented. Mice ocular surface epithelial disorders were induced by exposure of murine eyes to continuous controlled low-humidity air velocity in an intelligently controlled environmental system (ICES) for 21 days, which accelerated the tear evaporation. The mice were then randomized into three groups: the control group received PBS (0.01 M) treatment; a second group received 87.6 mM trehalose eyedrops treatment; and the third group received mice serum eyedrops treatment. Each treatment was administered as a 10 microl dose every 6 h for 14 days. The resultant changes in corneal barrier function and histopathologic examination of cornea and conjunctiva were analyzed and the level of apoptosis on the ocular surface was assessed using active caspase-3. After 14 days of treatment, the corneal fluorescein staining area, the ruffling and desquamating cells on the apical corneal epithelium, as well as the apoptotic cells on ocular surface epithelium had significantly reduced in eyes treated with trehalose compared with those treated with serum and PBS. In contrast, after 14 days of treatment, improvements in the thickness of the corneal epithelium, the squamous metaplasia in conjunctival epithelium and the number of goblet cells of the conjunctiva were less marked in eyes treated with trehalose compared with serum. These results demonstrated that trehalose could improve the appearance of ocular surface epithelial disorders due to desiccation through suppression of apoptosis. Trehalose produces some of the same responses as serum upon topical application and can maintain corneal health.

Effects of sequential artificial tear and cyclosporine emulsion therapy on conjunctival goblet cell density and transforming growth factor-beta2 production

PURPOSE

To evaluate the effects of sequential treatment with artificial tears and cyclosporine emulsion on conjunctival goblet cell density and production of transforming growth factor (TGF)-beta2 in patients with dry eye disease.

METHODS

Patients with dry eye disease (N = 6) defined by an Ocular Surface Disease Index symptom score >or=25, Schirmer test 1 <10 mm, and corneal fluorescein and conjunctival lissamine green staining scores >or=3 were treated with artificial tears (Refresh Plus; Allergan, Irvine, CA) 4 times a day for 4 weeks, followed by 0.05% cyclosporine emulsion (Restasis; Allergan) twice a day for 12 weeks. Impression cytology was performed on the bulbar conjunctiva of both eyes at baseline, after artificial tear therapy, and after 6 and 12 weeks of cyclosporine therapy. Goblet cells were counted in 5 representative microscopic fields per membrane in those taken from the temporal and inferior bulbar conjunctiva of the worse eye, and membranes taken from the fellow eye were immunostained for TGF-beta2.

RESULTS

There were no differences in mean goblet cell density between baseline and 4 weeks of artificial tears in the temporal and inferior bulbar specimens. After 6 weeks of cyclosporine emulsion, goblet cell density was significantly greater than baseline and artificial tears in the inferior bulbar conjunctiva (P < 0.01). After 12 weeks of cyclosporine emulsion, goblet cell density was significantly greater than baseline and artificial tears in both temporal and inferior bulbar sites (P < 0.01). The number of TGF-beta2-positive goblet cells was also noted to increase after 6 and 12 weeks of cyclosporine therapy (P < 0.001).

CONCLUSIONS

Cyclosporine emulsion, but not artificial tears, increases goblet cell density and production of the immunoregulatory factor TGF-beta2 in the bulbar conjunctiva in patients with dry eye.

Allogeneic serum eye drops for the treatment of severe dry eye in patients with chronic graft-versus-host disease

PURPOSE

To describe the use of allogeneic serum eye drops to treat 2 patients with chronic graft-versus-host disease (GVHD)-induced severe ocular surface disease.

METHODS

Small case series.

RESULTS

Conventional therapy failed to control the ocular symptoms of 2 patients with GVHD who presented with severe dry eye syndrome. Because autologous serum was unavailable in these cases, we used allogeneic serum eye drops as an alternate option for treating their ocular surface disease. Both donors had serologic tests performed before donation. Use of the allogeneic serum eye drops had a beneficial clinical effect, with marked attenuation of the patients' symptoms. This therapy proved to be safe during 10 months of treatment.

CONCLUSIONS

Allogeneic serum eye drops may be a good alternative treatment for patients with severe dry eyes caused by GVHD.

Growth Factors in the Tear Film: Role in Tissue Maintenance, Wound Healing, and Ocular Pathology

Numerous biologically active growth factors are secreted by the lacrimal gland and distributed via the tears over the ocular surface, where they affect cellular proliferation, migration, differentiation, and survival. The role of growth factors and their receptors in maintenance of tissue homeostasis and wound healing continues to be elucidated, and the effect of growth factor imbalances in ocular surface diseases is just beginning to be understood. For instance, in eyes with ocular surface diseases, including conjunctivitis, corneal erosion, keratitis, and corneal ulcers, epidermal growth factor release rates have been shown to be significantly lower than in normal eyes during reflex tearing. Future research into the mechanisms of dry eye disease will focus on reasons for decreased tear and growth factor production in the neuronal reflex loop or the acinar lacrimal gland cells. Animal models to test therapeutic approaches must be developed.

Albumin rescues ocular epithelial cells from cell death in dry eye

PURPOSE

Because autologous serum is useful for the treatment of severe dry eye, serum components may be a potential candidate for the treatment of dry eye. Serum albumin is abundantly contained in human serum and plays many physiologic roles. We investigated the efficacy of serum albumin in a dry eye animal model.

METHODS

Sprague-Dawley rats were used to make dry eye model rats according to a previous study. The central region of the corneal epithelium was scraped mechanically, and the rats were placed in a desiccation room (temperature, 23 +/- 2 degrees C; humidity, 28 +/- 2%; air flow, 2-4 m/s) for 12 hr. During desiccation, one eye of each rat was treated with human serum albumin eye drops, and the other eye was given a drop of phosphate buffered saline (PBS). Human corneal and conjunctival cell lines were used to investigate suppression effect of albumin on apoptosis induced by addition of apoptosis inducers or serum deprivation, respectively.

RESULTS

The erosion area was increased by 12 hr of desiccation. Albumin treatment decreased the area of erosion compared with PBS treatment. Apoptosis suppression assay using cell lines revealed that caspase-3 activation induced by serum deprivation and DNA fragmentation induced by addition of apoptosis inducers were dose-dependently suppressed by albumin.

CONCLUSIONS

Albumin showed a therapeutic effect in dry eye model rats. This efficacy may be related to the suppression of apoptosis by albumin.

Application of Umbilical Cord Serum Eyedrops for the Treatment of Dry Eye Syndrome

PURPOSE

To investigate the efficacy of umbilical cord serum eyedrops for the treatment of severe dry eye syndrome.

METHODS

Fifty-five eyes of 31 patients with severe dry eye syndrome were treated with umbilical cord serum eyedrops. Symptom scoring, tear film break-up time (BUT), Schirmer test, corneal sensitivity test, and corneal fluorescein staining were performed before and 1 and 2 months after treatment, and conjunctival impression cytology was performed before and 2 months after treatment. The concentrations of epidermal growth factor (EGF), vitamin A, and transforming growth factor-beta (TGF-beta) in umbilical cord serum and normal peripheral blood serum were measured.

RESULTS

Two months after treatment, significant improvement was observed in symptom score (from 3.07 +/- 0.54 to 0.96 +/- 0. 58), BUT (from 3.96 +/- 1.56 to 5.45 +/- 2.54 seconds), and keratoepitheliopathy score (from 4.87 +/- 3.22 to 1.71 +/- 1.84) (P < 0.01). There was no statistically significant change in Schirmer and corneal sensitivity tests. In impression cytology, the grade of squamous metaplasia (from 2.35 +/- 0.72 to 1.44 +/- 0.69) and goblet cell density (from 80.91 +/- 31.53 to 154.68 +/- 43.06 cell/mm) improved significantly (P < 0.01). The mean concentrations of EGF, TGF-beta, and vitamin A were 0.48 +/- 0.09, 57.14 +/- 18.98, and 230.85 +/- 13.39 ng/mL in umbilical cord serum and 0.14 +/- 0.03, 31.30 +/- 12.86, and 372.34 +/- 22.32 ng/mL in peripheral blood serum, respectively.

CONCLUSION

Umbilical cord serum contains essential tear components, and umbilical cord serum eyedrops are effective and safe for the treatment of severe dry eye syndrome.

Elucidation of apoptosis induced by serum deprivation in cultured conjunctival epithelial cells

BACKGROUND/AIMS

The conjunctival epithelial cell line, CCL20.2 (CCL), requires the presence of 10% fetal calf serum (FCS) in the medium to survive. To elucidate the molecular mechanism underlying such cell death, including the death signal for these cells, the activities of several caspases in the CCL were measured, and the effects of caspase inhibitors and serum components on cell death were examined.

METHODS

CCL was grown in Medium 199 containing 10% FCS, and the medium was changed to Medium 199 with or without 10% FCS, or medium without 10% FCS but containing caspase inhibitors or serum components. After 24 hours' incubation, the enzyme activities of caspases 1, 3, 8, and 9 in the culture supernatants were measured, and the effects of caspase inhibitors and serum components-for example, growth factors, lactoferrin, retinoic acid, were investigated.

RESULTS

DNA fragmentation was induced by serum deprivation, confirming that serum deprivation induces apoptosis in CCL. While the activities of caspases 3 and 8 were found to be increased, those of caspases 1 and 9 were not detected in the apoptotic cells. Z-VAD completely suppressed the caspase 3 activation, and specific inhibitors of caspases 1, 8, and 9 partially suppressed the activation. Serum deprivation induced a decrease in the cellular viability, which, however, partially recovered in the presence of caspase inhibitors, epidermal growth factor and retinoic acid.

CONCLUSION

These results suggest that the apoptosis induced by serum deprivation involves caspases 1, 3, 8, and 9, and is suppressed by caspase inhibitors. EGF and retinoic acid have a key role in the maintenance of the ocular surface.

Therapeutic Effect of Umbilical Cord Serum Eyedrops for Persistent Corneal Epithelial Defect

PURPOSE

To evaluate the therapeutic effect of umbilical cord serum in the treatment of persistent epithelial defect of the cornea.

METHODS

Fourteen eyes of 14 patients with persistent epithelial defect that had persisted for at least 2 weeks despite conventional treatment were treated with 20% umbilical cord serum eyedrops six times a day. The images of the epithelial defects were captured using a camera attached to a slit lamp biomicroscope and the areas of the epithelial defects were calculated. Treatment was considered effective for epithelial defect healing within 2 weeks, partially effective for healing within 2 to 4 weeks, and ineffective for healing requiring either more than 1 month or additional measures.

RESULTS

Mean duration of epithelial defect before treatment was 7.2 +/- 6.3 weeks, and mean area was 7.86 +/- 7.32 mm2. Umbilical cord serum therapy was effective in 6 eyes (42.9%), partially effective in 6 (42.9%), and ineffective in 2 (14.2%). Nevertheless, the epithelial defects in both the ineffective eyes were eventually healed within 8 weeks. Mean healing time in effective or partially effective cases was 2.75 +/- 1.06 weeks.

CONCLUSIONS

The use of umbilical cord serum eyedrops for the treatment of persistent epithelial defect is effective.

[Sterility of non-preserved autologous serum drops for treatment of persistent corneal epithelial defects]

PURPOSE

To investigate the sterility of non-preserved autologous serum drops in hospitalized patients with persistent corneal epithelial defects.

METHODS

Thirty patients with persistent corneal epithelial defects (aged between 28 and 85, mean 67+/-14 years) were treated with autologous serum drops in five different wards of a university eye hospital between October 2001 and March 2002. After centrifugation of freshly collected autologous blood, the serum was stored in sterile drop bottles at refrigerator temperature (7 degrees C) and applied undiluted every 1 or 2 h up to 7 days. Using blood, chocolate, endo, and Sabouraud agar media, we assessed the sterility of autologous serum drops on the day before application and on the 4th and 7th days. Examinations performed on the 1st and 4th days included 40 autologous serum drops each and on the 7th day 120 samples (40 serum drops, 40 bottle tops, and 40 bottle bottoms). The agar media for bacterial examination were read after 48 h of incubation time, and those for fungal examination were read after 21 days. All patients had received topical autologous serum therapy and prophylactic antibiotic drops for at least 7 days.

RESULTS

The time period of autologous serum treatment ranged from 7 to 28 (10+/-5) days. On the 1st and 4th days autologous serum drops were sterile. On the 7th day, 3 of 40 (7.5%) samples were contaminated with Staphylococcus epidermidis. Two of these contaminations were due to a combined serum drop and bottle top contamination (5%). A third case resulted from additional bottle bottom contamination (2.5%). None of the samples examined showed signs of fungal infection. During application of autologous serum as well as during the follow-up period no patient showed any symptoms of ocular infection.

CONCLUSIONS

The application of autologous serum has proven to be a practicable therapy in patients with persistent corneal epithelial defects. When the drops are applied by trained personnel, the absence of contamination can be ensured up to the 4th day. By additional application of prophylactic antibiotic drops, infections may be avoided even if refrigerated non-preserved autologous serum is used up to 7 days.

Changes in the tear film and ocular surface from dry eye syndrome

Dry eye syndrome (DES) refers to a spectrum of ocular surface diseases with diverse and frequently multiple aetiologies. The common feature of the various manifestations of DES is an abnormal tear film. Tear film abnormalities associated with DES are tear deficiency, owing to insufficient supply or excessive loss, and anomalous tear composition. These categorizations are artificial, as in reality both often coexist. DES disrupts the homeostasis of the tear film with its adjacent structures, and adversely affects its ability to perform essential functions such as supporting the ocular surface epithelium and preventing microbial invasion. In addition, whatever the initial trigger, moderate and severe DES is characterized by ocular surface inflammation, which in turn becomes the cause and consequence of cell damage, creating a self-perpetuating cycle of deterioration. Progress has been made in our understanding of the aetiology and pathogenesis of DES, and these advances have encouraged a proliferation of therapeutic options. This article aims to amalgamate prevailing ideas of DES development, and to assist in that, relevant aspects of the structure, function, and production of the tear film are reviewed. Additionally, a synopsis of therapeutic strategies for DES is presented, detailing treatments currently available, and those in development.

Comparison of autologous serum eye drops with conventional therapy in a randomised controlled crossover trial for ocular surface disease

AIMS

To evaluate the efficacy of 50% autologous serum drops against conventional treatment in ocular surface disorders refractory to normal treatments in a prospective randomised crossover trial.

METHOD

Patients fulfilling ophthalmological and haematological entry criteria were randomised to either 3 months of autologous serum 50% followed by 3 months of their conventional treatment, or 3 months of conventional treatment, followed by 3 months of autologous serum. Clinical assessments, including Schirmer's test, rose Bengal, and fluorescein staining, were carried out on entry and at monthly intervals. Impression cytology was performed at entry, 3 and 6 months. Grading was carried out on degrees of squamous metaplasia and goblet cell density. Subjective comfort was recorded daily using the "faces" scale. These categorical scores were converted to linear measurement using Rasch analysis. Statistical analysis was carried out using Wilcoxon's signed rank test and ANOVA.

RESULTS

16 patients were recruited with 31 eyes studied. The ocular surface diseases chiefly included Sjögren's syndrome (n = 6) and keratoconjunctivitis sicca (n = 5). Impression cytology available in 25 of 31 eyes showed significant improvement on serum treatment, p<0.02. Rasch weighted faces scores were statistically significantly better with serum, p<0.01.

CONCLUSION

The results of this randomised study provide further evidence of the beneficial effects of autologous serum in severe ocular surface disorders. For most of these patients, autologous serum was superior to conventional treatment for improving ocular surface health and subjective comfort.

Understanding dry eye syndrome

It was my great pleasure to have had the opportunity to give the conference address in addition to being honored by the Professor Dohlman Award. I am proud of the progress in the understanding of dry eye that has been made over the past couple of decades. However, the clinical application of the knowledge that has accumulated lies in the future. Thus far no effective medication has ever been developed for the treatment of severe dry eye. Cyclosoporine may become the first eyedrops to be used, and a series of new drugs containing androgens, immunomodulators, secretagogues, P2Y2 receptor agonists, and others may follow. I believe that medication for the treatment of dry eye will be developed in the not to distant future, and I hope that at the 4th conference in a few years time, we will be able to share these new treatments for the management of dry eye patients.

Growth Factor, Cytokine and Protease Interactions During Corneal Wound Healing

Healing of corneal injuries is an exceptionally complex process involving the integrated actions of multiple growth factors, cytokines, and proteases produced by epithelial cells, stromal keratocytes, inflammatory cells, and lacrimal gland cells. Following corneal injury, basal epithelial cells migrate and proliferate in response to chemotactic cytokines and mitogenic growth factors, including epidermal growth factor and keratinocyte growth factor. Simultaneously, keratocytes adjacent to the injured area undergo apoptosis under the Fas/Fas ligand system, while more distant keratocytes transform into activated fibroblasts and migrate into the wound, where they begin synthesizing new extracellular matrix components that form the scar tissue under the dominant influence of the TGFb/ CTGF system. Epithelial cells and activated stromal fibroblasts also secrete growth factors and cytokines that have paracrine and autocrine functions. Corneal repair proceeds for the next several weeks to months, during which time the gene expression profile slowly returns to the pre-injury pattern and the provisional scar matrix slowly remodels by actions of matrix metalloproteinases. While minor epithelial injuries heal by regeneration of normal architecture, large stromal injuries heal by repair with irregular scar tissue that impairs the optical properties of the cornea.Also, if the integrated regulation of the wound healing process is interrupted at any point, the wound fails to heal properly and a corneal ulcer develops. Better understanding of the cellular and molecular changes that occur during repair of corneal wounds will provide the opportunity to design agents that selectively modulate key phases of corneal wound healing, resulting in scars that more closely resemble normal corneal architecture.

Regulatory pathways in lacrimal gland epithelium

Tears are a complex fluid that continuously cover the exposed surface of the eye, namely the cornea and conjunctiva. Tears are secreted in response to the multitude of environmental stresses that can harm the ocular surface such as cold, mechanical stimulation, physical injury, noxious chemicals, as well as infections from various organisms. Tears also provide nutrients and remove waste from cells of the ocular surface. Because of the varied function of tears, tears are complex and are secreted by several different tissues. Tear secretion is under tight neural control allowing tears to respond rapidly to changing environmental conditions. The lacrimal gland is the main contributor to the aqueous portion of the tear film and the regulation of secretion from this gland has been well studied. Despite multiple redundencies in pathways to stimulate secretion from the lacrimal gland, defects can occur resulting in dry eye syndromes. These diseases can have deleterious effects on vision. In this review, we summarize the latest information regarding the regulatory pathways, which control secretion from the lacrimal gland, and their roles in the pathogenesis of dry eye syndromes.

Comparison of TGF-β1 in Tears Following Laser Subepithelial Keratomileusis and Photorefractive Keratectomy

PURPOSE

To compare the release of tear fluid transforming growth factor-beta1 (TGF-beta1) of 15 patients who underwent photorefractive keratectomy (PRK) in one eye and laser subepithelial keratomileusis (LASEK) in the other eye.

METHODS

Tear fluid samples were collected with scaled microcapillary tubes preoperatively (day 0) and on the first, second, and seventh postoperative days. We calculated the release of TGF-beta1 (tear fluid flow-corrected concentrations of TGF-beta1) by multiplying the concentration by capillary tear fluid flow and also evaluated corneal haze at 1, 3, and 6 months after PRK or LASEK.

RESULTS

The median TGF-beta1 release values were: Day 0: 50.6 pg/min (range 0 to 101.6 pg/min) for PRK and 56.7 pg/min (range 0 to 121.8 pg/min) for LASEK (P=.496); Day 1: 240.6 pg/min (range 56.6 to 1120.2 pg/min) for PRK and 155.2 pg/min (range 45.1 to 480.4 pg/min) for LASEK, which showed a significant difference between the two procedures (P=.041); Day 2: 395.7 pg/min (range 92.3 to 1150.7 pg/min) for PRK and 185.2 pg/min (range 41.4 to 872.5 pg/min) for LASEK (P=.004); and Day 7: 91.3 pg/min (range 0 to 225.4 pg/min) for PRK and 74.3 pg/min (range 0 to 187.1 pg/min) for LASEK, (P=.244). The mean corneal haze score at 1 month after PRK was 0.88 +/- 0.50 and 0.53 +/- 0.29 after LASEK, and a statistically significant difference was noted between the two groups (P=.005). At 3 months (P=.083) and 6 months (P=.157) after the procedures, there were no statistically significant differences.

CONCLUSIONS

A lower amount of tear fluid transforming growth factor-beta1 was released in the early postoperative days following LASEK than in PRK. The lower grade of corneal haze seen in LASEK than PRK in the early postoperative period may come from a decreased release of TGF-beta1, which may have a role in wound healing.

Distribution of growth factors and immune cells are altered in the lacrimal gland during pregnancy and lactation

We have undertaken a series of studies to elucidate the roles of growth factors (FGF-2, EGF, TGF-beta1) and prolactin (PRL) in lacrimal gland function during pregnancy and lactation, and to better understand the status of the immune system within the lacrimal gland during those physiological states. In this initial study, lacrimal glands of pregnant (d15, d29), lactating (9d, 22d), and adult female control rabbits, were evaluated by immunohistochemistry, Western blotting and image analysis. In control rabbits EGF, TGF-beta1, and PRL, were immunolocalized primarily in the apical cytoplasm of intralobular ductal epithelial cells, and acini demonstrated a basement membrane-associated immunopositivity for TGF-beta1. FGF-2 immunolocalized in myoepithelial cells in the basal ductal epithelium and complexed to the basement membrane enclosing ducts and acini. Cells immunopositive for immune cell markers (RTLA and CD18) were apparent primarily around interlobular ducts. In d29 pregnant rabbits immunopositivity for EGF and TGF-beta1 was increased within intralobular ducts, both apically and basally, and within some interlobular ductal epithelial cells. Immunopositivity for PRL was strongest in d29 pregnant rabbits within the apical and basal cytoplasm of intralobular ductal epithelial cells. Immunopositivity for FGF-2 in myoepithelial cells was strong in d15 and d29 pregnant rabbits, although basement membrane-associated immunopositivity around acini was often decreased. Immunostaining for EGF and TGF-beta1 in lactating rabbits was similar to that in d29 pregnant rabbits, although basement membrane-associated immunopositivity around acini was more comparable to controls. By 22d lactation immunopositivity for FGF-2 closely resembled that in controls. Image analysis of pregnant and lactating rabbits demonstrated that cells immunopositive for RTLA and CD18 were less abundant around ducts and more abundant between acini, although in 22d lactating rabbits the size of periductal foci was increased to nearly that of controls. Western blots correlated well with the immunohistochemistry. Our findings demonstrate that pregnancy and lactation are accompanied by a shift in the distributions of growth factors and PRL, suggestive of increased release both apically into the lacrimal fluid and basally into the interstitium. Additional shifts in the distributions of cells of the immune system from periductal foci to interacinar sites suggest that there is a recruitment of immune cells away from ducts and toward the connective tissue interstitium surrounding the acini, possibly as part of a heightened state of immune readiness during pregnancy and lactation.

Low molecular weight analysis of tears using matrix assisted laser desorption ionization-time of flight mass spectrometry

Many low molecular weight substances in human tears, including protein and lipid species, have yet to be characterized. Some of these uncharacterized substances may well be important in the pathogenesis of ocular surface disease or in ocular discomfort. The aim of this study was to build a biochemical profile of low molecular weight species in tears, and to determine its repeatability. A total of 80 tear samples were collected from 11 subjects. Tear samples were dialysed to remove salts, added to a matrix of alpha-cyano-4-hydroxycinnamic acid, and analysed using matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. Species were separated based on their mass to charge ratio (m:z). The repeatability of the appearance of the different species was analysed using logistic regression and diurnal and day-to-day repeatability were ascertained. Peptides were identified in the range of 848 3897 Da. Of these, 39 peptides were found to be present in more than 10/80 samples. There was no diurnal variation in the peptides. All species were found to occur repeatably, with the exception of peptide 1653 Da.This study has demonstrated that the majority of low molecular weight species in tears are repeatably present and do not exhibit diurnal variation. Further study aims to characterize these species and to identify changes in tear profiles between subject groups.

Quantitation of rat lacrimal secretion: a novel sandwich ELISA with high sensitivity

Modulation of lacrimal acinar cell tear secretion may involve multiple factors acting both in subtle and pronounced ways. Functional screens of recombinant protein products arising from gene array technologies, or protein fractions derived from lacrimal conditioned media or extracellular matrix, will require a highly sensitive assay capable of monitoring tear protein secretion by small replicate cultures. To improve significantly on current methods, a rat- and mouse-specific sandwich ELISA was developed. For this purpose, chickens and rabbits were immunized with serum-free secretion media from carbachol and VIP-stimulated rat lacrimal acinar cell cultures. Immune sera were characterized by ELISA, Western blotting and immunohistochemistry, and subsequently optimized for use in a sandwich ELISA. Both antisera detected a wide range of different rat tear proteins, and immunostained only the secretory granule-rich juxtalumenal region in sections of rat lacrimal gland. Chicken, but not rabbit, antiserum cross-reacted with rabbit and human tears. In sandwich ELISA, capture with purified chicken immunoglobulin fraction and detection with rabbit antiserum detected as little as 1 ng ml-1 tear protein in 10,000-fold diluted rat secretion medium--a level of sensitivity 8000 times greater than the rat tear peroxidase assay. Such specificity and sensitivity greatly reduce the quantity of media needed for assay, and makes feasible functional screens for scarce factors that may influence lacrimal secretory processes, and in turn possibly play a role in human lacrimal insufficiency syndromes.

MHC class II molecules, cathepsins, and La/SSB proteins in lacrimal acinar cell endomembranes

Sjögren's syndrome is a chronic autoimmune disease affecting the lacrimal glands and other epithelia. It has been suggested that acinar cells of the lacrimal glands provoke local autoimmune responses, leading to Sjögren's syndrome when they begin expressing major histocompatibility complex (MHC) class II molecules. We used isopycnic centrifugation and phase partitioning to resolve compartments that participate in traffic between the basolateral membranes and the endomembrane system to test the hypothesis that MHC class II molecules enter compartments that contain potential autoantigens, i.e., La/SSB, and enzymes capable of proteolytically processing autoantigen, i.e., cathepsins B and D. A series of compartments identified as secretory vesicle membranes, prelysosomes, and microdomains of the trans-Golgi network involved in traffic to the basolateral membrane, to the secretory vesicles, and to the prelysosomes were all prominent loci of MHC class II molecules, La/SSB, and cathepsins B and D. These observations support the thesis that lacrimal gland acinar cells that have been induced to express MHC class II molecules function as autoantigen processing and presenting cells.