Influence of gender, sex steroid hormones, and the hypothalamic-pituitary axis on the structure and function of the lacrimal gland

Smart Contact Lenses as Wearable Ophthalmic Devices for Disease Monitoring and Health Management

The eye contains a complex network of physiological information and biomarkers for monitoring disease and managing health, and ocular devices can be used to effectively perform point-of-care diagnosis and disease management. This comprehensive review describes the target biomarkers and various diseases, including ophthalmic diseases, metabolic diseases, and neurological diseases, based on the physiological and anatomical background of the eye. This review also includes the recent technologies utilized in eye-wearable medical devices and the latest trends in wearable ophthalmic devices, specifically smart contact lenses for the purpose of disease management. After introducing other ocular devices such as the retinal prosthesis, we further discuss the current challenges and potential possibilities of smart contact lenses.

Expression of Androgen and Estrogen Receptors in the Human Lacrimal Gland

Lacrimal gland dysfunction causes dry eye disease (DED) due to decreased tear production. Aqueous-deficient DED is more prevalent in women, suggesting that sexual dimorphism of the human lacrimal gland could be a potential cause. Sex steroid hormones are a key factor in the development of sexual dimorphism. This study aimed to quantify estrogen receptor (ER) and androgen receptor (AR) expression in the human lacrimal gland and compare it between sexes. RNA was isolated from 35 human lacrimal gland tissue samples collected from 19 cornea donors. AR, ERα, and ERβ mRNA was identified in all samples, and their expression was quantified using qPCR. Immunohistochemical staining was performed on selected samples to evaluate protein expression of the receptors. ERα mRNA expression was significantly higher than the expression of AR and ERβ. No difference in sex steroid hormone (SSH) receptor mRNA expression was observed between sexes, and no correlation was observed with age. If ERα protein expression is found to be concordant with mRNA expression, it should be investigated further as a potential target for hormone therapy of DED. Further research is needed to elucidate the role of sex steroid hormone receptors in sex-related differences of lacrimal gland structure and disease.

Dry eye syndrome: comprehensive etiologies and recent clinical trials

Dry eye syndrome (DES) is multifactorial and likely to be a cause of concern more so than ever given the rapid pace of modernization, which is directly associated with many of the extrinsic causative factors. Additionally, recent studies have also postulated novel etiologies that may provide the basis for alternative treatment methods clinically. Such insights are especially important given that current approaches to tackle DES remains suboptimal. This review will primarily cover a comprehensive list of causes that lead to DES, summarize all the upcoming and ongoing clinical trials that focuses on treating this disease as well as discuss future potential treatments that can improve inclusivity.

Comparison of Meibomian Gland Loss between Demodex-infested Group and Dry Eye Patients without Demodex Infestation

Purpose: To compare the degree of meibomian gland drop-out associated with Demodex infestation using non-contact meibography.Methods: We performed noncontact meibography using an infrared digital camera on 24 adult subjects infested by Demodex and 40 without infestation. The right upper and lower lids were scored based on the loss of meibomian glands, and the scores of the upper and lower eyelids were summed to obtain the total meiboscore for each subject. Meiboscores were evaluated according to Demodex infestation and gender in each group.Results: Sixty-four eyes of 64 people were enrolled in this study. The study subjects had an average age of 67.9 years (range, 40-79 years; men, 65.2 years; women, 69.1 years). There was a significant association between Demodex infestation and total meiboscore and upper and lower eyelid meiboscores (p = 0.000, p = 0.002, p = 0.004, respectively). There was no significant difference in the meiboscores between men and women. Age and meiboscore suggested a weak positive correlation; however, the R2 value was low, due to the concentrated age distribution of the study population.Conclusions: Based on noncontact meibography, the authors concluded that the prevalence of changes in the meibomian glands was significantly related to Demodex infestation; however, there was no significant difference between men and women.

Sex Hormones Related Ocular Dryness in Breast Cancer Women

Background: Dry eye syndrome (DES) is strictly connected to systemic and topical sex hormones. Breast cancer treatment, the subsequent hormonal therapy, the subsequent hyperandrogenism and the early sudden menopause, may be responsible for ocular surface system failure and its clinical manifestation as dry eye disease. This local dryness is part of the breast cancer iatrogenic dryness, which affects overall mucosal tissue in the fragile population of those with breast cancer. Methods: A literature review regarding the role of sex hormone changes and systemic hormonal replacement treatments (SHRT) in DES available on PubMed and Web of Science was made without any restriction of language. Results: Androgens exert their role on the ocular surface supporting meibomian gland function and exerting a pro-sebaceous effect. Estrogen seems to show a pro/inflammatory role on the ocular surface, while SHRT effects on dry eye are still not well defined, determining apparently contradictory consequences on the ocular surface homeostasis. The role of sex hormones on dry eye pathogenesis is most likely the result of a strict crosstalk between the protective androgens effects and the androgen-modulating effects of estrogens on the meibomian glands. Conclusions: Patients with a pathological or iatrogenic hormonal imbalance, such as in the case of breast cancer, should be assessed for dry eye disease, as well as systemic dryness, in order to restore their social and personal quality of life.

Sexual dimorphism of the extraorbital lacrimal glands in SF-1 knockout mice

Sexual dimorphism (SD) represents all the differences between males and females of the same species. SD of the murine lacrimal gland and the major effect of testosterone on its formation are well documented. Steroidogenic factor-1 (SF-1, NR5a1) is a nuclear receptor essential for the fetal development of steroid hormones producing organs and SF-1 knockout mice (Sf-1 KO) are therefore born without gonads and adrenal glands. The aim of this study was to investigate whether SD in lacrimal glands is present in the absence of exposure to sex hormones during development. Lacrimal glands from adult Sf-1 KO male and female mice without hormonal exposure, and from males that were treated with testosterone propionate (TP) prior to sacrifice, were examined. After sacrifice, glandular tissue was processed using standard histological procedures. Paraffin sections were analysed by stereology and immunostained against the androgen receptor (AR). Our results showed that there were no statistically significant differences in the mean volumes of acini, connective tissue or ductal system between males, females, and males on TP. The same pertains to the mean length of the ducts in all three groups. In the absence of sex hormones, sex chromosomes proved to be insufficient in inducing sexual dimorphism in LG. However, nuclei of the acinar cells in males on TP were positive for AR, whereas in males without TP no expression of AR was detected. Administration of TP induced the expression of AR in the nuclei of acinar cells of males but did not affect the morphology of LG. We conclude that SD in the lacrimal gland is not present in Sf-1 KO mice and this suggests that sex hormones have a major role in the development of SD in the lacrimal gland.

Effects of Topical Mucolytic Agents on the Tears and Ocular Surface: A Plausible Animal Model of Mucin-Deficient Dry Eye

Purpose

A topical mucolytic agent, N-acetylcysteine (NAC), has been used to create an animal model without the intestinal mucus layer. In this study, we investigated the effects of topical NAC on the tears and ocular surface.

Methods

NAC-treated models were established by topically administering 10% NAC four times daily for 5 days in male Sprague-Dawley rats. Clinical parameters and the expression of mucin proteins and genes were evaluated. Alterations in the conjunctival epithelium and goblet cells were observed.

Results

The NAC group showed significant decreases in tear secretion, corneal wetting ability, tear MUC5AC concentration, and conjunctival goblet cell numbers as compared with the control group (all P < 0.01). In addition, significant increases in corneal fluorescein score and rose bengal scores were observed in the NAC group versus in the control group (P < 0.05 and P < 0.01, respectively). Hematoxylin and eosin (H&E) staining and scanning electron microscopy clearly showed damage in the epithelial cell layer and microvilli of the NAC group. Although there was no significant difference in MUC16 gene expression, the MUC16 concentration of the tear film and ocular surface tissue was significantly increased in the NAC group versus in the control group (P < 0.01 and P < 0.05, respectively). Five-day treatment with 3% diquafosol had minimal therapeutic effect in NAC-treated rat eyes.

Conclusions

Topical administration of 10% NAC induced ocular surface damage and tear film instability by prompting MUC16 disruption and release from the ocular surface. This animal model could be used to study dry eye disease, especially the mucin-deficiency subtype.

Age-related Autoimmune Changes in Lacrimal Glands

Aging is a complex process associated with dysregulation of the immune system and low levels of inflammation, often associated with the onset of many pathologies. The lacrimal gland (LG) plays a vital role in the maintenance of ocular physiology and changes related to aging directly affect eye diseases. The dysregulation of the immune system in aging leads to quantitative and qualitative changes in antibodies and cytokines. While there is a gradual decline of the immune system, there is an increase in autoimmunity, with a reciprocal pathway between low levels of inflammation and aging mechanisms. Elderly C57BL/6J mice spontaneously show LGs infiltration that is characterized by Th1 but not Th17 cells. The aging of the LG is related to functional alterations, reduced innervation and decreased secretory activities. Lymphocytic infiltration, destruction, and atrophy of glandular parenchyma, ductal dilatation, and secretion of inflammatory mediators modify the volume and composition of tears. Oxidative stress, the capacity to metabolize and eliminate toxic substances decreased in aging, is also associated with the reduction of LG functionality and the pathogenesis of autoimmune diseases. Although further studies are required for a better understanding of autoimmunity and aging of the LG, we described anatomic and immunology aspects that have been described so far.

Immediate Effect of 3% Diquafosol Ophthalmic Solution on Tear MUC5AC Concentration and Corneal Wetting Ability in Normal and Experimental Keratoconjunctivitis Sicca Rat Models

PURPOSE

To evaluate the immediate effect of 3% diquafosol ophthalmic solution on tear MUC5AC concentration, periodic acid-Schiff (PAS)-positive goblet cells, and tear film stability in normal and keratoconjunctivitis sicca (KCS) rat models.

METHODS

Rats were divided into normal and KCS groups. 3% of diquafosol solution was instilled into the right eye and normal saline into the left eye in both groups. To determine the peak time of tear MUC5AC concentration, tears were collected after 3% diquafosol instillation every 5 min up to 20 min. The tear film stability and the numbers of PAS-positive goblet cells were compared in both models.

RESULTS

After diquafosol instillation, tear MUC5AC concentration increased steadily for 15 min, at which point the MUC5AC concentration reached its peak. In both normal and KCS groups, the MUC5AC concentration at 15 min was higher after instillation of 3% diquafosol solution (17.77 ± 2.09 ng/ml in the normal group, 9.65 ± 3.51 ng/ml in the KCS group) than that after saline instillation (13.74 ± 2.87 ng/ml in the normal group, 8.19 ± 3.99 ng/ml in the KCS group) (p = 0.018 for both). The corneal wetting ability was significantly longer after instillation of 3% diquafosol solution compared with that after instillation of normal saline in the normal group (p = 0.018). The percentage of PAS-positive goblet cells after the instillation of 3% diquafosol solution was significantly lower than that after instillation of normal saline in both models (p = 0.018 for both).

CONCLUSIONS

Diquafosol ophthalmic solution was effective in stimulating mucin secretion in both normal and KCS rat models, and the peak time of tear MUC5AC concentration was 15 min after diquafosol instillation. The increased tear MUC5AC concentration was accompanied by improved tear film stability and a decreased percentage of PAS-positive goblet cells.

Absolute quantification of human tear lactoferrin using multiple reaction monitoring technique with stable-isotopic labeling

The mass spectrometry technique of multiple reaction monitoring (MRM) was used to quantify and compare the expression level of lactoferrin in tear films among control, prostate cancer (CaP), and benign prostate hyperplasia (BPH) groups. Tear samples from 14 men with CaP, 15 men with BPH, and 14 controls were analyzed in the study. Collected tears (2 μl) of each sample were digested with trypsin overnight at 37 °C without any pretreatment, and tear lactoferrin was quantified using a lactoferrin-specific peptide, VPSHAVVAR, both using natural/light and isotopic-labeled/heavy peptides with MRM. The average tear lactoferrin concentration was 1.01 ± 0.07 μg/μl in control samples, 0.96 ± 0.07 μg/μl in the BPH group, and 0.98 ± 0.07 μg/μl in the CaP group. Our study is the first to quantify tear proteins using a total of 43 individual (non-pooled) tear samples and showed that direct digestion of tear samples is suitable for MRM studies. The calculated average lactoferrin concentration in the control group matched that in the published range of human tear lactoferrin concentration measured by enzyme-linked immunosorbent assay (ELISA). Moreover, the lactoferrin was stably expressed across all of the samples, with no significant differences being observed among the control, BPH, and CaP groups.

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.

Sex-steroid imbalance in females and dry eye

Dry eye (DE) is a multifactorial disorder of the ocular surface unit that results in eye discomfort, visual disturbance and ocular surface damage. It is one of the most common complaints in daily ophthalmic practice. The risk of DE increases with age in both sexes, while its incidence is higher among females. In addition, the condition of menopause in aging women may also contribute to DE onset or worsening as a consequence of an overall hormonal imbalance. Sex hormones play a key role in ocular surface physiology and they impact differently on ocular surface tissues. Reduced estrogen levels were historically thought to be responsible in age-related DE onset but more recent investigations have reconsidered the role of androgens that are present and exert a protective function on the ocular surface. Hormone levels themselves, withdrawal changes in hormone levels, and the changes in hormone-receptor responsiveness are all important factors but it remains to be fully elucidated how estrogen or androgen insufficiency act alone or together in a combined imbalance or interplay to raise the risk of disease. The purpose of this review is to briefly outline current scientific evidence on the influence of androgens and estrogens, on the Lachrymal and Meibomian glands and on ocular surface epithelia including conjunctival goblet cells during reproductive and menopausal periods. The role of sex steroids is also discussed in relation to the pathogenesis of different forms of DE and Sjogren's syndrome (SS). The impact of systemic hormone therapy (HT) in DE post-menopausal women still appears as a controversial issue, despite the many clinical studies. Finally, the outcomes of topical applications of steroid-based products are summarized, underlying the need for potential (tear) biomarker(s) in the rationale of DE-targeted therapy.

Sex hormones and the dry eye

The greater prevalence of dry eye in women compared to men suggests that sex hormones may have a role in this condition. This review aims to present evidence for how sex hormones may affect the ocular structures involved in the production, regulation and maintenance of the normal tear film. It is hypothesised that hormone changes alter the homeostasis of the ocular surface and contribute to dry eye. Androgens impact on the structure and function of the meibomian and lacrimal glands and therefore androgen deficiency is, at least in part, associated with the aetiology of dry eye. In contrast, reports of the effects of oestrogen and progesterone on these ocular structures and on the conjunctiva are contradictory and the mechanisms of action of these female-specific sex hormones in the eye are not well understood. The uncertainty of the effects of oestrogen and progesterone on dry eye symptoms is reflected in the controversial relationship between hormone replacement therapy and the signs and symptoms of dry eye. Current understanding of sex hormone influences on the immune system suggests that oestrogen may modulate a cascade of inflammatory events, which underlie dry eye.

Changes in tear film, corneal topography, and refractive status in premenopausal women during menstrual cycle

PURPOSE

To investigate the changes in a questionnaire based subjective symptomatology, tear film break-up time, tear volume, corneal topography, and refractive status in premenopausal women during menstrual cycle.

METHODS

Seventeen premenopausal females and 15 healthy males were enrolled in this prospective study. After routine ophthalmologic examination, an ocular surface disease index questionnaire was administered, tear film break-up time (TBUT), and Schirmer I tests were performed. Keratometry readings and refractive status were also obtained. All examinations were repeated at day 21, day 12 and day 2.

RESULTS

OSDI score in day 21 was significantly lower than that in day 12 (p=0.004) and day 2 (p=0.01) in the female patients; however, no significant change was found in the male subjects (p>0.05). No statistically significant difference was found in TBUT and Schirmer I tests, keratometry, and refraction results in both of the female and male subjects at all of the test points (p>0.05). There was a significant correlation between OSDI score and TBUT (p=0.02, p=0.03, respectively), and Schirmer I test at day 12 (p=0.004, p=0.008, respectively). A significant negative correlation was found between oestrogen level and horizontal keratometry values at day 21 (r=-0.5, p=0.03; r=-0.4, p=0.04, respectively) for the right and left eyes in the female subjects.

CONCLUSION

Our study confirms that fluctuations in the blood levels of oestrogen produce alterations in ocular surface equilibrium during the menstrual cycle and consequently affect the subjective dry eye symptoms in female patients. However, no ocular surface parameter changes were observed.

Emerging drugs for the treatment of dry eye disease

INTRODUCTION

Dry eye disease (DED) is a common, age-related ocular condition that in its mildest forms causes bothersome symptoms of ocular discomfort, fatigue, and visual disturbance that interfere with quality of life and in its more severe forms causes chronic pain and fluctuating vision. Though it is highly prevalent and costs billions of dollars to manage, current treatments have largely been inadequate, making it a frustrating condition, both for physicians and patients alike.

AREAS COVERED

This article will cover the recently discovered pathophysiology of DED that has prompted investigators to explore new molecules that target the core mechanisms that drive DED. These include anti-inflammatory/immune-modulatory drugs, secretagogues, lubricant, hormones, and autologous serum. Their potential mechanism of action and data from recent trials on efficacy/safety will be reviewed.

EXPERT OPINION

The emerging drugs have a vast range of putative mechanisms of action that may not only provide symptomatic relief but may potentially break the vicious cycle of DED and provide long-lasting cure. Current and future research may change our perspective on DED and redefine its treatment algorithms.

Tear secretion and tear stability of women on hormonal contraceptives

Purpose

To investigate the effects of injectable hormonal contraceptives on tear secretion and tear stability of females within child bearing age in Nigeria.

Methods

The experimental group consisted of 32 healthy females (mean age was 34.72 ± 5.44) on injectable hormonal contraceptives; and the control group comprised 32 females (mean age was 34.66 ± 5.24) who were not on hormonal contraceptives. The tear stability and tear secretion were measured using the non-invasive tear break up time (NITBUT) technique and Schirmer's strips, respectively. All the females were at follicular phase of menstrual cycle. The plasma levels of progesterone and estradiol of all subjects were determined.

Results

There were no remarkable effects of injectable hormonal contraceptives on tear secretion (P  = 0.929) and tear stability (P  = 0.814). There were weak correlations between the plasma levels of progesterone and tear secretion (r  = −0.232, P  > 0.05), as well as with tear stability (r  = −0.322, P  > 0.05). Also, there were weak positive correlation between plasma levels of estradiol and tear secretion (r  = 0.304, P  > 0.05), as well as with tear stability (r  = 0.262, P  > 0.05). There were no significant differences in tear stability between the experimental and control groups (P  > 0.05).

Conclusions

Injectable hormonal contraceptives had no significant effects on tear secretion and tear stability of healthy women of childbearing age. Further studies may be required to determine the effects of hormonal contraceptives on tear volume and stability of women with dry eyes.

A Clinical Study of Acupuncture and SSP (Silver Spike Point) Electro-therapy for Dry Eye Syndrome

The present study was designed as a clinical trial to assess the efficacy of acupuncture and silver spike point (SSP) electro-therapy on dry eye syndrome. A total of 43 dry eye syndrome patients participated in the present study. Subjects were divided into control, acupuncture and SSP electro-therapy groups. The three groups were all given artificial tears treatment. Patients in the treatment groups were given two 20-minute treatments of either acupuncture or SSP. Assessment was carried out using the Basal Schirmer test, tear break-up time (BUT), visual analog scale (VAS) and an overall score of eye condition. After four weeks of treatment, both the acupuncture and SSP treatment groups showed improvements over the control group, in Schirmer tests of the left eye and average tearing of both eyes. After 8 weeks of treatment, both treatment groups showed improvements over the control group both in Schirmer tests and VAS. For the right eye, treatment groups showed significant improvements in Schirmer test and VAS versus the control group averages for both eyes. There was no significant difference in BUT at any time. Comparing scores before and after treatment, the acupuncture and SSP groups showed a significant improvement compared to the control group. The acupuncture group showed a greater 8-week improvement in Schirmer tests scores compared to the SSP group. However, the SSP group patients used fewer applications of artificial tears. Acupuncture and SSP electro-therapy were effective in increasing tear secretion in patients with dry eye syndrome. The SSP electro-therapy not only alleviated dry eye syndrome, but also reduced the number of applications of artificial tears necessary.

Transduction, tropism, and biodistribution of AAV vectors in the lacrimal gland

PURPOSE

The lacrimal gland (LG) delivers defensive and metabolic factors to the ocular surface. These functions may be disrupted in several diseases, and for most of them there is no cure. The aim of this study is to investigate conditions and limitations for using adeno-associated virus (AAV) vectors as gene transfer agents to LG.

METHODS

Eight-week-old Balb/c mice were used to investigate route, gene expression, and time course of AAV gene vector transfer to LG. AAV vectors encoding firefly luciferase were administered to the LG and luciferase expression was evaluated in vivo by immunohistochemistry. Ocular surface and neutralizing antibodies were also evaluated.

RESULTS

The present work revealed that AAV vectors are able to delivery DNA to the LGs of mice. Direct injection had the highest level of transduction, and topical ocular drops the lowest. Overall, the AAV strain with highest transduction activity as measured by both luminescence and immunohistochemistry was AAV9, followed by AAV 5w8 and AAV5. Transduction was not different between sexes, could be detected as soon as 24 hours after injection, and lasted for at least 30 days (study termination). No tissue damage was observed when compared with controls. All vectors with detectable LG transduction induced neutralizing antibodies.

CONCLUSIONS

LG gene delivery by AAV vectors appears to be both safe and well tolerated. The choice of vector influences both the overall transduction activity, as well as the spread of vector to other organs. This work supports the use of AAV-mediated gene therapy for dry eye.

Sex- and gender-based differences in healthy and diseased eyes

PURPOSE

The aim of this study was to identify sex- and gender-based differences in ocular anatomy, physiology, and disease susceptibility or manifestation.

METHODS

Review of current indexed literature was conducted.

RESULTS

Sex and sex hormones influence the lacrimal system, eyelids and blinking, corneal anatomy and disease, aqueous humor dynamics and glaucoma, crystalline lens and cataract, uveitis and retinal disease, ocular circulation, and optic nerve anatomy and disease. Systemic conditions, particularly autoimmune disease, and conditions that are unique to women, such as pregnancy and menopause, further illustrate the effects of sex hormones on the eye. Gender-based differences in ocular conditions and disease should be considered within the context of the underlying physical and social environment.

CONCLUSIONS

Many sex- and gender-based differences exist in healthy and diseased eyes.

Neural regulation of lacrimal gland secretory processes: relevance in dry eye diseases

The lacrimal gland is the major contributor to the aqueous layer of the tear film which consists of water, electrolytes and proteins. The amount and composition of this layer is critical for the health, maintenance, and protection of the cells of the cornea and conjunctiva (the ocular surface). Small changes in the concentration of tear electrolytes have been correlated with dry eye syndrome. While the mechanisms of secretion of water, electrolytes and proteins from the lacrimal gland differ, all three are under tight neural control. This allows for a rapid response to meet the needs of the cells of the ocular surface in response to environmental conditions. The neural response consists of the activation of the afferent sensory nerves in the cornea and conjunctiva to stimulate efferent parasympathetic and sympathetic nerves that innervate the lacrimal gland. Neurotransmitters are released from the stimulated parasympathetic and sympathetic nerves that cause secretion of water, electrolytes, and proteins from the lacrimal gland and onto the ocular surface. This review focuses on the neural regulation of lacrimal gland secretion under normal and dry eye conditions.

Tearful relationships? Sex, hormones, the lacrimal gland, and aqueous-deficient dry eye

Sex and the endocrine system exert a significant influence on the physiology and pathophysiology of the lacrimal gland. The purpose of this article is to briefly review the nature and magnitude of these interactions between sex, hormones and lacrimal tissue, and to address how they may relate to the pathogenesis of aqueous-deficient dry eye. Towards this end, this article has a 3-fold approach: first, to summarize the influence of androgens, estrogens, glucocorticoids, mineralocorticoids, retinoic acid, prolactin, alpha-melanocyte stimulating hormone, adrenocorticotropic hormone, luteinizing hormone, follicle-stimulating hormone, growth hormone, thyroid-stimulating hormone, arginine vasopressin, oxytocin, thyroxine, parathyroid hormone, insulin, glucagon, melatonin, human chorionic gonadotropin and cholecystokinin on the structure and function of the lacrimal gland; second, to discuss the mechanism of action of each hormone on lacrimal tissue; and third, to discuss the clinical relevance of the endocrine-lacrimal gland interrelationship, with a particular focus on each hormone's role (i.e. if relevant) in the development of aqueous-tear deficiency.

Primary Sjogren's syndrome: current and prospective therapies

OBJECTIVE

To summarize data on existing and experimental therapies for primary Sjogren's syndrome (pSS), referring both to sicca syndrome and to other systemic disease manifestations.

METHODS

Relevant English and non-English articles acquired through Medline were reviewed.

RESULTS

pSS usually has a benign clinical course, centered on sicca features and general musculoskeletal manifestations, and is managed symptomatically. However, a subset of patients develops more severe extraglandular disease that warrants close monitoring and aggressive treatment. For dry eyes and mouth, nonpharmacologic measures to preserve secretions, and tear and saliva substitutes, offer some symptomatic relief. Muscarinic agonists and topical cyclosporine yield well-documented improvement in ocular sicca features. Although traditional antirheumatic drugs are used empirically for polyarthritis and other Sjogren's symptoms, their efficacy in pSS overall and as disease-modifying agents is limited. For the potential severe, nonexocrine manifestations complicating pSS, standard high-dose immunosuppression is used. Among the biologic agents already examined in pSS, those targeting tumor necrosis factor (TNF)-alpha failed to demonstrate significant benefit. Nonetheless, rituximab and other B-cell-depleting therapies appear promising.

CONCLUSIONS

Treatment of pSS patients with severe extraglandular disease should differ from that of patients with predominantly sicca features and/or general muscoloskeletal manifestations. pSS treatment is mainly symptomatic, primarily directed against sicca complaints. The traditional anti-rheumatic agents show limited efficacy in the systemic process and use of systemic TNF-alpha inhibitors has been very disappointing. B cell depleting treatments and other newer biologic therapies appear more promising.

A novel mouse protein differentially regulated by androgens in the submandibular and lacrimal glands

We characterized a cDNA clone derived from the female mouse submandibular gland (SMG). The transcript of this cDNA was approximately 1.2kb in size and predicted to code a 165-amino acid protein with a putative signal peptide for a secretory pathway. This protein, named submandibular androgen-repressed protein (SMARP), had homology in the N-terminal region with members of the glutamine/glutamic acid-rich protein (GRP) family from rats. Northern blot analysis revealed that SMARP mRNA is expressed, out of the major mouse organs, only in the SMG and exorbital lacrimal gland (LG), with much more abundance in the former. For the SMG, the level of SMARP mRNA was 36 times higher in females than males, whereas for the LG it was 28 times higher in males than females. Furthermore, the level of SMARP mRNA was increased in the SMG but reduced in the LG with castration in males, whereas it was reduced in SMG but increased in LG after administration of testosterone in females or castrated males. In situ hybridization detected the signal for SMARP mRNA in the female SMG, and immunohistochemistry detected the signal for SMARP protein in the female SMG and male LG. In the female SMG, SMARP mRNA, and protein were localized intensively in a subpopulation of acinar cells, whereas in the male LG, SMARP protein was distributed diffusely in all acinar cells. These results suggested that SMARP is a secretory protein whose expression is regulated by androgens negatively in the SMG and positively in the LG.

Estrogen and androgen repression of two female specific lacrimal lipocalins in hamster: Pituitary independent and sex hormone receptor mediated action

Sexual dimorphism in lacrimal gland (LG) gene expression is believed to be due to direct inductive effects of androgens mediated by androgen receptors (AR) but hypophysectomy dramatically curtails these inductive effects. Since, functional estrogen receptors (ER) could not be detected in LG, estrogen effects on LG are believed to be indirectly mediated by changes in levels of pituitary hormones. We found that two lipocalins expressed in female hamster LG display an unusual and marked repression by both androgens and estrogens, which could be detected both at the level of transcripts and proteins. Here, we investigate whether these repressions, (i) require presence of pituitary and (ii) are mediated by androgen and estrogen receptors. Pituitary-ablation but not gonadectomy reduced LG weights in hamster. However, both pituitary-ablation and gonadectomy induced abundant expression of the LG lipocalins, which were markedly repressed by androgen or estrogen treatment. AR- and ER-antagonists prevented these repressions and only ER-alpha- but not ER-beta-specific agonist could mimic the estrogenic repression. AR transcript and protein and ER-alpha transcript were also detected in hamster LG. Thus, pituitary factors are neither essential for the expression of these LG lipocalins nor for their estrogenic or androgenic repressions and these repressions are very likely mediated by functional ER and AR present in LG.

Symptomatic dry eye treatment with autologous platelet-rich plasma

BACKGROUND

Autologous platelet-rich plasma (PRP) has been proven to be very effective on tissue regeneration and wound healing. Here we investigate the potential use of PRP in the treatment of symptomatic dry eye.

METHODS

Eighteen consecutive patients with symptomatic dry eye were treated with topical PRP and followed up for 1 month. Disappearance of subjective symptoms, increase in best corrected visual acuity, tear meniscus, tear breakup time, decrease in inflammation, fluorescein staining and improvement in impression cytology were measured.

RESULTS

Symptoms improved significantly in 89% of the patients, 28% improved at least 1 line of best corrected visual acuity. A significant improvement on lachrymal meniscus and conjunctival hyperemia and a decrease or disappearance of corneal fluorescein staining were observed. Impression cytology revealed a significant increase in conjunctival goblet cells.

CONCLUSION

Treatment of patients suffering from significant dry eye symptoms with autologous RPR proved to be very effective, improving both patient symptoms and major clinical signs.

Serum dehydroepiandrosterone sulphate level in age-related macular degeneration

PURPOSE

To evaluate plasma dehydroepiandrosterone sulphate (DHEAS) levels in patients diagnosed with age-related macular degeneration (AMD) and controls.

DESIGN

Case-controlled, prospective, comparative noninterventional study.

METHODS

This study involved 32 men and 35 women with exudative AMD, 37 men and 38 women with nonexudative AMD, and 32 men and 32 women of an age-matched control group. The Wisconsin Age-Related Maculopathy Grading System was used to asses the severity of AMD lesions. DHEAS levels were measured and compared according to a gender based subdivision. Analysis of variance was used to assess the association between DHEAS and AMD. Linear regression model was used to examine the relation among DHEAS level and AMD severity scale.

RESULTS

Mean +/- SD of DHEAS levels in exudative AMD, nonexudative AMD, and controls in men was 2.67 +/- 0.68 micromol/l, 2.89 +/- 0.95 micromol/l, and 4.43 +/- 1.44 micromol/l, respectively (P = .001), and in women was 1.64 +/- 0.72 micromol/l, 1.85 +/- 0.73 micromol/l, and 2.78 +/- 0.91 micromol/l, respectively (P = .001). Post hoc Tukey analyses revealed a significant reduction in serum DHEAS level in both AMD groups, compared with controls for men and women (P = .001), while no difference was found between AMD groups in both men and women (P = .668 and 0.49, respectively). Regression analyses revealed an inverse correlation among serum DHEAS level and AMD severity scale both in men and women (P = .006 and .007, respectively).

CONCLUSIONS

This study suggests an inverse correlation between serum DHEAS level and AMD severity scale with a considerably reduced DHEAS level in AMD.

Anatomy and Histopathology of the Human Lacrimal Gland

PURPOSE

To review the anatomy and histopathologic changes of the human main lacrimal gland.

METHODS

Samples of lacrimal gland including palpebral lobes and orbital lobes were taken in autopsies, and the relationship between histopathologic changes and age and sex, as well as histopathologic differences between palpebral and orbital lobes of the lacrimal gland, were studied using light microscopy.

RESULTS

Various histopathologic changes were observed in the human main lacrimal gland as follows: acinar atrophy; periacinar fibrosis; periductal fibrosis; interlobular ductal dilatation; interlobular ductal proliferation; lymphocytic infiltration; and fatty infiltration. Several histopathologic differences exist between the palpebral and orbital lobes. There were statistically significant correlations between age and diffuse fibrosis, diffuse atrophy, and periductal fibrosis in the orbital lobes of women. Diffuse fibrosis and diffuse atrophy in orbital lobes were more frequently observed in women than in men.

CONCLUSION

It is speculated that periductal fibrosis is related to a decrease of tear flow with age and that interlobular ductal dilatation in palpebral lobes may be caused by stenosis of the excretory duct in conjunctival fornix. However, the mechanisms of these histopathologic changes in the human main lacrimal gland are not yet clear.

Androgen Status of the Nonautoimmune Dry Eye Subtypes

PURPOSE

To evaluate androgen levels of patients diagnosed with nonautoimmune dry eye, either with meibomian gland dysfunction (MGD) or without MGD (non-MGD), and normal control subjects. This is a prospective, comparative, case-control study.

METHODS

Sixty-four (32 men and 32 women) subjects were enrolled for each of the three diagnostic groups. All dry eye patients were symptom positive. Nonfasting testosterone (T), sex hormone-binding globulin, serum albumin, dehydroepiandrosterone (DHEA), and DHEA sulphate levels of all study participants were determined using either automated immunoenzymatic assay, or standard radioimmunoassay. Analysis of variance was used to compare androgen levels among the three diagnostic groups in a gender-based design, followed by post-hoc multiple comparisons with the Tukey honestly significant difference test.

RESULTS

Mean T levels in men and women of the three diagnostic groups were not significantly different (p = 0.808, p = 0.156, respectively; ANOVA). Statistical analyses of the three diagnostic groups revealed a significant difference for men and women in bioavailable T levels (p = 0.002, p = 0.014, respectively; ANOVA), DHEA levels (p = 0.009, p = 0.004, respectively; ANOVA), and DHEA sulphate levels (p = 0.001, p = 0.001, respectively; ANOVA), whereas there was no statistically significant difference between non-MGD dry eye patients and controls for any of the measured androgen levels according to the post-hoc tests.

CONCLUSION

This study demonstrates that the androgen pool of nonautoimmune dry eye patients with MGD is significantly depleted compared with that of non-MGD and control cases.

Long-term effects of tibolone on ocular functions in postmenopausal women

Hormone replacement therapy has been widely used for the prevention of postmenopausal osteoporosis and treatment of climacteric symptoms for many years, but its effect on ocular functions remains unclear. The aim of the study was to evaluate the long-term effects of tibolone on ocular functions in postmenopausal women. A total of 77 healthy women with at least 1 year of spontaneous menopause were enrolled in the study. Forty women were treated with tibolone for 6 months and 37 women were left untreated. All these patients underwent ophthalmic examination including visual acuity, intraocular pressure (IOP), tear functions, blue-on-yellow and white-on-white Humphrey visual field (HVF), visual evoked potentials (VEP) and electroretinography (ERG). There were significant differences in mean deviation of blue-on-yellow HVF, and oscillatory potentials (O1, O2, and O4) in the ERGs of the chronic tibolone users and the control (P < 0.0001, P = 0.001, P < 0.0001 and 0.05, respectively). However, no significant differences were observed in visual acuity, IOP, tear functions, white-on-white HVF and VEP. We concluded that, although tibolone had no effects on visual acuity, IOP, tear functions and VEP, it might cause some early adverse effects on the electrophysiologic and structural characteristics of the retina, which are detected by these sensitive assays. Randomized placebo-controlled studies with larger groups are needed in future research.

Immunohistochemical analysis of secretoglobin SCGB 2A1 expression in human ocular glands and tissues

Human secretoglobin (SCGB) 2A1 (or lipophilin C, lacryglobin, mammaglobin B) is a small protein of unknown function that forms heterodimers with secretoglobin 1D1 (lipophilin A) in tears. SCGB 2A1 is homologous to mammaglobin (mammaglobin A) and the C3 component of prostatein, the major secretory protein of the rat ventral prostate. Androgen-dependent expression of SCGB 2A1 has been observed in the prostate. Besides identification of SCGB 2A1 in the tear proteome only its mRNA had been detected in the lacrimal gland. Here, we report expression of SCGB 2A1 in all ocular glands and in the keratinized stratified squamous epithelium of the eyelid as well as in the stratified epithelium of the conjunctiva and in the orbicularis oculi muscle. Almost all of these tissues are also known to express the androgen receptor. Therefore, we conclude that presence of the androgen signalling machinery could be the main general determinant of SCGB 2A1 expression. Implications of the presence in tear fluid of an androgen-regulated secretoglobin, which most likely binds hydrophobic ligands, for tear film lipid layer formation and function is discussed.

Insulin secretion by rat lacrimal glands: effects of systemic and local variables

To understand the secretory mechanisms and physiological role of insulin in the tear film, the present study examined 1) the time course of insulin secretion in the tear film under glucose intravenous stimulation, 2) the glucose- and carbachol-induced insulin secretion from isolated lacrimal gland (LG), 3) the effect of insulin on glucose consumption by the cornea, and 4) the expression of insulin, pancreatic duodenal homeobox-1 (PDX-1), and glucose transport proteins (GLUTs) in LG tissue. The insulin level in the tear film of 8-wk-old male Wistar rats increased from 0.6 +/- 0.45 to 3.7 +/- 1.3 ng/ml in the initial minutes after glucose stimulation. In vitro assays demonstrated that higher glucose concentrations from 2.8 to 16.7 mM, 200 microM carbachol, or 40 mM KCl significantly increased insulin secretion from lacrimal glands compared with controls, but did not detect C-peptide as measured by RIA. Glucose consumption by corneal tissue, evaluated by radiolabeled D-[U-14C]glucose uptake, was 24.07 +/- 0.61 and was enhanced to 31.63 +/- 3.15 nmol x cornea(-1) x 2 h(-1) in the presence of 6 nM insulin (P = 0.033) and to 37.5 +/- 3.7 nmol x cornea(-1) x 2 h(-1) in the presence of 11.2 mM glucose (P = 0.015). Insulin and PDX-1 mRNA was detected in LG. Insulin was located in the apical areas of acinar cells by immunoperoxidase and the expression of GLUT-1, but not PDX-1, was confirmed by Western blot. These findings suggest that insulin secretion in the tear film is influenced by local stimuli such as nutrient and neural inputs and that this hormone plays a metabolic role in ocular surface tissues. These data also indicate that under normal conditions the insulin secreted by LG is stored, but it is not clear that is locally produced in the LG.

Combined esterified estrogen and methyltestosterone treatment for dry eye syndrome in postmenopausal women

PURPOSE

To determine whether systemic replacement with combined esterified estrogen (EE) and methyltestosterone (MT) (EE + MT) would reduce symptoms and promote clinical improvement in postmenopausal women with dry eye syndrome (DES).

DESIGN

Retrospective, noncomparative, interventional case series.

METHODS

Investigators reviewed the charts of 11 postmenopausal women treated within the last 3 years with EE + MT.

RESULTS

The mean patient age was 65.2 years (standard deviation [SD] 11.4, range 48-84 years). The mean treatment duration was 12.2 months (SD 6.2 months, range 4-24 months). Ten (91%) of 11 patients reported improvement in dry eye symptoms while receiving treatment. For these 10, relief occurred after an average of 4.1 months of treatment (SD 3.2, range, 1-9 months).

CONCLUSIONS

Treatment with EE + MT may be efficacious for DES of various etiologies. A randomized placebo-controlled trial is planned to further evaluate these encouraging findings.

Menopause and dry eye. A possible relationship

The hormonal status and in particular sex steroids play a role in the ocular surface homeostasis and function, during the whole life and in both sexes, accomplished by estrogenic and androgenic receptors located on corneal and conjunctival epithelia and Meibomian gland. The ocular surface is an integrated unit and any dysfunction results in a scarce or unstable preocular tear film which produces dry eye, a chronic inflammatory condition with increasing incidence as people get older but always more frequent among females. In post-menopausal women endocrine changes join the aging effects in the pathogenesis of dry eye, but still it remains controversial whether estrogen or androgen deficiency or their imbalance impair ocular surface function. Another questionable issue concerns the efficacy of hormonal replacement therapy in the amelioration of dry eye symptoms and recovery of tear function, since the scientific literature stands in between a therapeutic or a promoting effect of eye dryness. Therapy of dry eye is usually based upon topical administration of tear substitutes; estrogen or androgen-based eye drops represents a promising innovative treatment based upon important scientific rationale.

Down regulation of interleukin-1beta-induced nitric oxide production in lacrimal gland acinar cells by sex steroids

PURPOSE

Because the ocular surface is constantly exposed to allergens and irritants, it was reasoned that one cause of dry eye might be damage from inflammatory responses normally regulated by sex steroids. To test this hypothesis, we determined if sex steroids could down regulate nitric oxide (NO) production induced by interleukin-1beta (IL-1beta) in cultured rabbit lacrimal gland acinar cells.

METHODS

Cultured rabbit lacrimal gland acinar cells were exposed to IL-1beta to stimulate NO production. Stimulated cells were treated with different sex steroids and expression of iNOS protein determined by Western blotting and NO production by a nitrate/nitrite colorimetric assay.

RESULTS

It was found that the androgens testosterone, dihydrotestosterone, dehydroepiandrosterone and dehydroepiandrosterone-sulfate and 17beta-estradiol were able to inhibit interleukin-1beta-induced NO production in rabbit lacrimal gland acinar cells at physiological concentrations, while progesterone was not able to inhibit NO production. Sex steroid inhibition of NO production was not due to down regulation of iNOS protein production nor was it due to down regulation of GTP cyclohydrolase I with consequent loss of tetrahydrobiopterin production.

CONCLUSIONS

The results reported here show that androgens and estrogens can down regulate cytokine-mediated responses in cells that are part of the ocular surface protection system and thereby may have an important role in regulating inflammatory responses in the eye. Deficiencies in these steroids, as occurs in postmenopausal women, may lead to damage of the cells responsible for producing the fluids that protect the ocular surface and subsequently to dry eye disease.

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.

Influence des hormones sur le film lacrymal

Tear film quality depends on fine regulatory mechanisms affected by neuronal and hormonal influences. Indeed, receptors for androgens, estrogens, progesterone and prolactin have been identified in several ocular tissues in the rat, rabbit and in humans. The eye is thus a target organ for sex hormones, particularly the androgens. These hormones regulate the immune system, the morphology and secretory functions of lacrimal glands and the functioning of Meibomian glands. The influence of hormone replacement therapy in menopausal women remains unclear, as some authors support the idea that they improve the quality and the volume of tear film, whereas others have shown that they increase the risk of dry eye. Finally, knowledge of the interactions between the hormones that influence the lacrimal glands is essential for the understanding of the regulation of lacrimal gland function. However, the data presently available strongly suggest that optimal bioavailable androgen levels are essential for normal lacrimal gland function and that prolactin and estrogens also play important roles in providing a hormonal milieu that contributes to normal lacrimal gland function.

The tear film and ocular mucins

The trilaminar tear film, composed of the lipid, aqueous and mucin layers, has many functions including defending the ocular surface. The aqueous layer has several soluble antimicrobial factors that protect the ocular surface. Ocular mucins have recently been studied with regard to their role in the defense of the eye as well as in dry eye syndromes. To date, 15 mucin genes have been identified, and six of these mucin genes are localized to or secreted by ocular glands or epithelia. Understanding the production, secretion and function of ocular mucins will aid in the treatment of dry eye syndromes and ocular surface microbial infections.

Antiinflammatory therapy for dry eye

PURPOSE

To present evidence establishing the relationship between inflammation and dry eye and supporting the use of antiinflammatory therapy for dry eye.

DESIGN

Analysis of literature.

METHODS

Research studies that evaluated inflammation in dry eye pathogenesis and clinical trials of antiinflammatory therapies for dry eye were reviewed.

RESULTS

There is increasing evidence that decreased tear secretion, decreased tear turnover, and desiccation promote inflammation on the ocular surface. An increase in soluble mediators (cytokines and proteases) in the tear fluid, adhesion molecule expression by the conjunctival epithelium, and T-cell infiltration of the conjunctiva have been observed in dry eye patients. This inflammation appears to have a role in the pathogenesis of the ocular surface epithelial disease, termed keratoconjunctivitis sicca (KCS), that develops in dry eye. Clinical improvement of KCS has been observed after therapy with antiinflammatory agents including corticosteroids, cyclosporin and doxycycline. Cyclosporin A emulsion was approved by the Food and Drug Administration as therapy for dry eye. Randomized placebo-controlled FDA clinical trials showed that cyclosporine A was superior to vehicle in stimulating aqueous tear production, decreasing corneal punctuate fluorescein staining, reducing symptoms of blurred vision, and decreasing artificial tear use in patients with KCS. No ocular or systemic toxicity was observed from this medication.

CONCLUSIONS

Ocular surface and lacrimal gland inflammation has been identified in dry eye that plays a role in the pathogenesis of KCS. Antiinflammatory therapy has efficacy for treating KCS. Cyclosporin A is the first FDA approved therapy for this indication. It improved signs and symptoms of KCS, and it is safe for long-term use.