Androgen support of lacrimal gland function

Exocrine gland structure-function relationships

Fluid secretion by exocrine glandular organs is essential to the survival of mammals. Each glandular unit within the body is uniquely organized to carry out its own specific functions, with failure to establish these specialized structures resulting in impaired organ function. Here, we review glandular organs in terms of shared and divergent architecture. We first describe the structural organization of the diverse glandular secretory units (the end-pieces) and their fluid transporting systems (the ducts) within the mammalian system, focusing on how tissue architecture corresponds to functional output. We then highlight how defects in development of end-piece and ductal architecture impacts secretory function. Finally, we discuss how knowledge of exocrine gland structure-function relationships can be applied to the development of new diagnostics, regenerative approaches and tissue regeneration.

Evaluation of dry eye and Meibomian gland dysfunction in female androgenetic alopecia patients

PURPOSE

To evaluate dry eye tests and Meibomian gland functions in female androgenetic alopecia patients.

MATERIALS AND METHODS

Twenty left eyes of 20 female androgenetic alopecia patients (Group 1) and 20 left eyes of 20 healthy female volunteers (Group 2) were enrolled in the study. The presence of dry eye was evaluated with Schirmer 1 test, invasive tear film break-up time (T-BUT), Oxford scale scoring and Ocular Surface Disease Index (OSDI) score assessments. Evaluation of upper and lower eyelid Meibomian glands was performed using infrared filter of a slit-lamp biomicroscope, and the drop out ratio was scored for each eyelid.

RESULTS

The mean ages of Group 1 and Group 2 were 48.3 ± 6.6 (range, 38-58) and 49.8 ± 5.4 (range, 38-59) years, respectively (P = 0.437). Mean T-BUT was statistically significantly lower in Group 1 (P = 0.013); mean OSDI score was significantly higher in Group 1 (P = 0.049). Mean Schirmer 1 score was lower and mean Oxford score was higher in Group 1, but the differences were not statistically significant (P = 0.291, P = 0.088, respectively). In addition, upper, lower and total meiboscores were significantly higher in Group 1 (P = 0.007, P = 0.003, P = 0.002, respectively).

CONCLUSION

Alterations in sex hormones play a role in the pathogenesis of both female androgenetic alopecia and Meibomian gland dysfunction. Significant differences were detected in the results of dry eye tests and Meibomian gland dropout ratios between subjects with female androgenetic alopecia and healthy control subjects. For this reason, female androgenetic alopecia patients should be examined for dry eye and Meibomian gland dysfunction and should be treated to prevent serious consequences.

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.

A Literature Review on Thyrotoxic Periodic Paralysis

Thyrotoxic periodic paralysis (TPP) is a rare disease of the muscles that presents with painless weakness of the muscles. The patients usually have hypokalemia and hyperthyroidism with elevations in the level of triiodothyronine (T3) and thyroxine (T4). The muscle weakness is usually transient, and the patients in many cases suffer from recurrent episodes of muscle paralysis. This flaccid muscle paralysis predominantly affects the proximal and lower extremities group of muscles more than the distal and upper extremity muscles. This condition is one of the drastic complications of Graves's disease and, unfortunately, may require admission and treatment in the critical care units. It is often not recognized during the initial attack in the American population as the prevalence is very low among the Caucasian population and people from North America. However, while the prevalence is extremely low in the Caucasian population, it is known to be 10 times more common among the Asian population when compared with the Caucasian population. Furthermore, while the diseases of the thyroid gland are more common in females, this rare disease predominantly affects male sex. It is treated by reversing the hypokalemia, which can in itself prove to be fatal if not corrected quickly, and this is followed by treatment to restore the euthyroid state. A literature review on this reversible cause of muscle weakness is very important to better understand this disease.

The Effect of Androgens on Proinflammatory Cytokine Secretion from Human Ocular Surface Epithelial Cells

Purpose: The purpose of this study is to explore the effects of dihydrotestosterone (DHT) on lipopolysaccharide (LPS)-induced proinflammatory cytokine release in human ocular surface epithelial cells exposed to LPS and LPS-binding protein (LBP).Methods: Immortalized human corneal, conjunctival, and meibomian gland epithelial cells were cultured in keratinocyte-free medium. After confluency, they were exposed to a stratification medium Dulbecco's modified Eagle medium (DMEM)/F12 in the presence of fetal bovine serum and were exposed to vehicle, LPS + LBP, or DHT. Culture media were processed for multiplex-bead analysis of specific proinflammatory cytokines including interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-2, IL-4, IL-8, IL-6, IL-10, IL-1β, vascular endothelial growth factor (VEGF)-A. Cytokine concentrations were compared by analysis of variance with Tukey post hoc testing. p < 0.05 was considered statistically significant.Results: The results are LPS + LBP-induced the secretion of IFN-γ, IL-6, IL-10, IL-1β, VEGF-A cytokines in corneal epithelial cells; TNF-α, IL-2, IL-8, IL-6, IL-1β, VEGF-A cytokines in conjunctival epithelial cells; and IL-8, IL-6, IL-1β, VEGF-A cytokines in meibomian gland epithelial cells. When these LPS + LBP-stimulated cells were exposed to DHT for 2 days, it was found that DHT suppressed the secretion of IL-6, IL-10, IL-1β, VEGF-A cytokines in corneal epithelial cells; TNF-α, IL-6, IL-1β, VEGF-A cytokines in conjunctival epithelial cells; and IL-6, IL-1β, VEGF-A cytokines in meibomian gland epithelial cells.Conclusion: LPS + LBP is shown to induce the secretion of certain proinflammatory cytokines from ocular surface and adnexal epithelial cells. DHT showed anti-inflammatory activity by suppressing some of those cytokines in these cell lines.

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.

Thyrotoxic periodic paralysis: case report and review of the literature

Introduction

Thyrotoxic periodic paralysis (TPP) is a rare and potentially lethal complication of hyperthyroidism. It is characterized by sudden onset paralysis associated with hypokalemia. Management includes prompt normalization of potassium, which results in resolution of the paralysis. Definitive treatment of hyperthyroidism resolves TPP completely.

Case presentation

A 23-year-old African American male patient presented to the emergency room at the University of Mississippi Medical Center, USA in November 2016 with sudden onset quadriplegia. He also endorsed a history of weight loss, palpitations, heat intolerance and tremors. The patient reported similar episodes of quadriplegia in the past, which were associated with hypokalemia and resolved with normalization of potassium levels. Physical examination was significant for exophthalmos, smooth goiter with bruit consistent with the diagnosis of Graves’ disease. Laboratory assessment showed severe hypokalemia, hypomagnesemia, suppressed thyroid stimulating hormone (TSH) and high free thyroxine (T4). Urine potassium creatinine ratio was less than one, indicating transcellular shift as the cause of hypokalemia. After normalization of potassium and magnesium, the paralysis resolved in 12 hours. He was started on methimazole. On follow up, the patient was clinically and biochemically euthyroid with no further episodes of paralysis.

Take-away lesson

TPP is a rare and reversible cause of paralysis. Physicians need to be aware of the diagnostic and treatment modalities as delayed recognition in treatment could result in potential harm or unnecessary interventions.

[Ocular surface aging: Pathophysiology and consequences for management]

All the components of the ocular surface and the lacrimal system are affected by aging. Aging induces lacrimal gland fibrosis, Meibomian gland dysfunction, loss of corneal sensitivity, decreased corneal cell density, impairment of immune defences, increased local inflammation associated with hormonal changes, conjunctivochalasis, lid abnormalities, etc. Furthermore, homeostasis of the ocular surface may be altered by various age-related systemic comorbidities and iatrogenic interventions. Altogether, aging is considered the most predominant risk factor for dry eye disease. The increasing knowledge of the pathophysiology of aging of the ocular surface allows for refinement of the management of ocular surface disease in the elderly.

TFOS DEWS II Sex, Gender, and Hormones Report

One of the most compelling features of dry eye disease (DED) is that it occurs more frequently in women than men. In fact, the female sex is a significant risk factor for the development of DED. This sex-related difference in DED prevalence is attributed in large part to the effects of sex steroids (e.g. androgens, estrogens), hypothalamic-pituitary hormones, glucocorticoids, insulin, insulin-like growth factor 1 and thyroid hormones, as well as to the sex chromosome complement, sex-specific autosomal factors and epigenetics (e.g. microRNAs). In addition to sex, gender also appears to be a risk factor for DED. "Gender" and "sex" are words that are often used interchangeably, but they have distinct meanings. "Gender" refers to a person's self-representation as a man or woman, whereas "sex" distinguishes males and females based on their biological characteristics. Both gender and sex affect DED risk, presentation of the disease, immune responses, pain, care-seeking behaviors, service utilization, and myriad other facets of eye health. Overall, sex, gender and hormones play a major role in the regulation of ocular surface and adnexal tissues, and in the difference in DED prevalence between women and men. The purpose of this Subcommittee report is to review and critique the nature of this role, as well as to recommend areas for future research to advance our understanding of the interrelationships between sex, gender, hormones and DED.

Effect of dihydrotestosterone on the expression of mucin 1 and the activity of Wnt signaling in mouse corneal epithelial cells

AIM

To explore the effects of the androgen dihydrotestosterone on the expression of mucin 1 (MUC1) and the activity of Wnt signaling in mouse corneal epithelial cells.

METHODS

Primary mouse corneal epithelial cells were isolated from the corneas of BALB/c mice. Quantitative real-time polymerase chain reaction, immunofluorescence and Western blot analysis were used to quantify the differential expression of selected genes. The androgen receptor was silenced by transfecting cells with androgen receptor shRNAs. TOP-Flash and FOP-flash reporter plasmids were used to measure β-catenin-driven transcription.

RESULTS

Dihydrotestosterone treatment increased MUC1 expression and activated the Wnt signaling pathway and led to the translocation of β-catenin and upregulation of the Wnt downstream target gene TATA box binding protein and urokinase plasminogen activator. These effects were prevented by downregulating the androgen receptor.

CONCLUSION

Androgens may protect against dry eye by regulating the expression of MUC1 which is stimulated by the activation of Wnt signaling via the androgen receptor. An understanding of the mechanisms associated with androgen-mediated protection against dry eye is an important step in developing new therapies for this disease.

Androgen deficiency and dry eye syndrome in the aging male

PURPOSE

To evaluate the relationship between androgen levels and subjective and objective measures of dry eye syndrome (DES).

METHODS

A total of 263 male patients from the Miami Veterans Affairs Medical Center eye clinic aged ≥50 were recruited for this prospective cross-sectional study. Patients completed Dry Eye Questionnaire 5, underwent tear film evaluation, and had serum androgen levels measured. The correlations between androgen levels, DES composite scores, DES symptoms, and global, lipid, and aqueous tear film parameters were evaluated.

RESULTS

Two hundred sixty-three patients with a mean age of 69 (50-95) were examined. There was no linear association between composite DES scores (generated using latent class analysis) and androgen levels. However, eyes with high DES scores (0.95-1.0) had higher levels of sex hormone-binding globulin (P = 0.03) and lower levels of dehydroepiandrosterone sulfate (DHEAS) (P = 0.02), androstenedione (A) (P = 0.02), and androstane-3α,17β-diol glucuronide (P = 0.03) compared to eyes with intermediate (0.05-0.95) or low (0-0.05) scores. There were no strong correlations between tear film measures and androgen levels. Regarding global parameters, a weak inverse correlation was found between corneal staining and A (r = -0.17, P = 0.009). For lipid parameters, a weak correlation existed between tear breakup time (TBUT) and A (r = 0.15, P = 0.02). When considering aqueous and lipid deficiency independently, the association between TBUT and A existed only with aqueous tear deficiency (r = 0.66, P = 0.002). Regarding aqueous parameters, a weak correlation existed between Schirmer test and DHEAS (r = 0.13, P = 0.047) and A (r = 0.21, P = 0.001).

CONCLUSIONS

There was a weak correlation between higher levels of androstenedione and healthier global, lipid, and aqueous tear film parameters.

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.

Human lacrimal gland regeneration: Perspectives and review of literature

The human lacrimal gland is an essential component of the lacrimal functional unit (LFU). Any perturbation of this unit can lead to the debilitating morbid condition called the dry eye syndrome (DES). The current line of therapy available for dry eye remains supportive and palliative with the patient being dependent on life long and frequent administration of lubricating eye drops. Even advanced therapies like punctual plugs, cyclosporine B administration, and salivary gland auto-transplantation have led to a limited success. Under these scenarios, the option of cell based therapy needs to be explored to provide better and long term relief to these patients. This review gives an overview of the efforts in lacrimal gland regeneration and examines the past and ongoing research in cell based therapies in animals as well as human lacrimal gland cultures. The authors discuss their first of its kind functionally viable human lacrimal gland in vitro culture system from fresh exenteration specimens. A brief overview of research in near future and the potential implications of lacrimal gland regenerative therapies have been discussed.

Episodes of paralysis in Chinese men with thyrotoxic periodic paralysis are associated with elevated serum testosterone

BACKGROUND

The strong predilection for thyrotoxic periodic paralysis (TPP) to occur in males suggests androgen may contribute to its pathogenesis. We therefore sought to determine if serum total and free testosterone (TT and FT) concentrations differed among patients with TPP during episodes of paralysis, patients with TPP between episodes of paralysis, and patients with Graves' disease (GD) not having TPP.

METHODS

A total of 105 Chinese men were included in the study, and were divided into three groups. Group 1 consisted of men with TPP who were studied during episodes of paralysis; group 2 consisted of men with TPP who were studied between episodes of paralysis; group 3 consisted of men with GD not having TPP. Patients in each were different persons. Serum electrolytes, free triiodothyronine (FT3), free thyroxine (FT4), TT, and FT were measured. Multiple regression analyses and analysis of covariance were performed to analyze the relationship of serum parameters, group status, and age.

RESULTS

One multiple regression analysis was used to determine if serum TT concentrations were associated with age, FT3, FT4, or group status. This analysis indicated that age, FT4 level, and group status were significantly and independently associated with serum TT concentrations. With regard to group status, patients in group 1 had serum TT concentrations 0.92 ng/mL higher than patients in group 3 (p=0.033). As to FT4 level, TT concentrations increased by 0.016 ng/mL for each additional pmol/L of FT4 (p=0.002). Another multiple regression analysis was used to determine if serum FT concentrations were associated with age, FT3, FT4, group status, or serum TT concentrations. This analysis revealed that serum TT concentrations and group status were significantly and independently associated with serum FT concentrations. In terms of group status, patients in group 1 had serum FT concentrations of 2.11 pg/mL greater on average than patients in group 3 (p=0.006).

CONCLUSIONS

We infer that episodes of paralysis in Chinese men with TPP are associated with elevated serum testosterone. We also found serum TT and FT concentrations of men with GD are both affected by group status; serum TT rather than FT concentrations are associated with thyroid function.

Thyrotoxic periodic paralysis: clinical and molecular aspects

Thyrotoxic periodic paralysis (TPP) is a rare complication of hyperthyroidism that most often affects young East Asian males but increasingly also in other ethnic groups. The typical presentation is acute attacks varying from mild weakness to total paralysis starting at night or in the early morning a few hours after a heavy meal, alcohol abuse or strenuous exercise with complete recovery within 72 h. Signs and symptoms of hyperthyroidism may not be obvious. The hallmark is hypokalemia from increased cellular sodium/potassium-ATPase pump activity with transport of potassium from the extracellular to the intracellular space in combination with reduced potassium output. Recently, KCNJ18 gene mutations which alter the function of an inwardly rectifying potassium channel named Kir2.6 have been detected in 0-33 % of cases. Hence, the pathophysiology in TPP includes a genetic predisposition, thyrotoxicosis and environmental influences and the relative impact from each of these factors may vary. The initial treatment, which is potassium supplementation, should be given with caution due to a high risk of hyperkalemia. Propranolol is an alternative first-line therapeutic option based on the assumption that hyperadrenergic activity is involved in the pathogenesis. If thyroid function tests are unobtainable in the acute situation the diagnosis is supported by the findings of hypokalemia, low spot urine potassium excretion, hypophosphatemia with hypophosphaturia, high spot urine calcium/phosphate ratio, and electrocardiographic abnormalities as tachycardia, atrial fibrillation, high QRS voltage, and atrioventricular block. Definitive treatment is cure of the hyperthyroidism. The underlying mechanisms of TPP remain, however, incompletely understood awaiting further studies.

Na(+)/K(+)-ATPase expression changes in the rabbit lacrimal glands during pregnancy

PURPOSE

To investigate the expressional changes of Na(+)/K(+)-ATPase subunits in the lacrimal glands (LG) of term pregnant rabbits.

METHODS

LG were obtained from term pregnant rabbits and age-matched female control rabbits for laser capture microdissection (LCM), real time RT-PCR, western blot, and immunofluorescence. The mRNA and proteins of α1, α2, β1, β2, and β3 subunits of Na(+)/K(+)-ATPase were detected and quantified.

RESULTS

Although only the mRNA for β3 from whole LG of pregnant rabbits was significantly different from that of normal controls, many mRNA levels for α1, α2, β1, β2, and β3 from acini and epithelial cells from various duct segments that were collected by LCM were significantly different from those of normal control rabbits. Western blots demonstrated that the expressions of all three β subunits were significantly higher in pregnant rabbits, while both α subunits remained unchanged during pregnancy. Interestingly, immunofluorescence results showed that the distribution patterns of all Na(+)/K(+)-ATPase subunits during pregnancy were similar to those of the control rabbits.

CONCLUSIONS

Changes were found in mRNA and protein expressions of Na(+)/K(+)-ATPase subunits in LG from term pregnant rabbits and these changes suggest a role in the pregnancy-related LG secretion changes and dry eye symptoms observed in these animals.

Influence of sex hormones and genetic predisposition in Sjögren's syndrome: a new clue to the immunopathogenesis of dry eye disease

Sjögren's syndrome (SS) is a chronic autoimmune disease characterized by lymphocytic infiltration, destruction of lacrimal and salivary glands and the presence of serum autoantibodies. Most women that suffer from SS are post-menopausal however, not all post-menopausal women develop SS, suggesting that other factors, in addition to the decrease in ovarian hormones, are necessary for the development of SS. The purposes of this study were to investigate a) the time course of lymphocytic infiltration and apoptosis in the lacrimal gland after ovariectomy, b) if a predisposed genetic background for SS aggravates the effects of decreasing levels of sex hormones in the lacrimal glands and c) if physiological doses of estrogen or androgen prevent the effects observed after ovariectomy. Six weeks old mice that are genetically predisposed to SS (NOD.B10.H2(b)) and control (C57BL/10) mice were either sham operated, ovariectomized (OVX), OVX + 17β estradiol (E(2)) or OVX + Dihydrotestosterone (DHT). Lacrimal glands were collected at 3, 7, 21 or 30 days after surgery and processed for immunohistochemistry to measure CD4(+), CD8(+) T cells, B220(+) B cells, nuclear DNA degradation and cleaved caspase-3 activity. Quantification of the staining was done by light microscopy and Image Pro Plus software. The results of our study show that lymphocytic infiltration preceded lacrimal gland apoptosis after ovariectomy. Moreover, removal of ovarian sex hormones accelerated these effects in the genetically predisposed animal and these effects were more severe and persistent compared to control animals. In addition, sex hormone replacement at physiological levels prevented these symptoms. The mechanisms by which decreased levels of sex hormones caused lymphocytic infiltration and apoptosis and the interaction of lack of sex hormones with the genetic elements remain to be elucidated.

A review on recent advances in dry eye: Pathogenesis and management

Keratoconjunctivitis sicca, more commonly known as dry eye, is an extremely common and often unrecognized disease. It is the condition in ophthalmology that in its mild grade of severity will affect most of the population at one time or other. Due to a wide variety of presentations and symptoms, it often frustrates the ophthalmologists as well as patients. Due to multifactorial and elusive etiology, it is often challenging to treat dry eye. Ocular surface disorders are also clinically important to treat especially in terms of visual acuity. Xero-dacryology is therefore becoming a very important branch of ophthalmology. Recent studies have given insight into the inflammatory etiology of dry eye. The conventional and main approach to the treatment of dry eye is providing lubricating eye drops or tear substitutes. However, the newer treatment approach is to target the underlying cause of dry eye instead of conventional symptomatic relief. In light of the above knowledge, the present article focuses on newer theories on pathogenesis of dry eye and their impact on dry eye management. METHOD OF LITERATURE SEARCH: A systematic literature review was performed using PubMed databases in two steps. The first step was oriented to articles published for dry eye. The second step was focused on the role of inflammation and anti-inflammatory therapy for dry eye. The search strategy was not limited by year of publication. A manual literature search was also undertaken from authentic reference books on ocular surface disease.

Novel etiopathophysiological aspects of thyrotoxic periodic paralysis

Thyrotoxicosis can lead to thyrotoxic periodic paralysis (TPP), an endocrine channelopathy, and is the most common cause of acquired periodic paralysis. Typically, paralytic attacks cease when hyperthyroidism is abolished, and recur if hyperthyroidism returns. TPP is often underdiagnosed, as it has diverse periodicity, duration and intensity. The age at which patients develop TPP closely follows the age at which thyrotoxicosis occurs. All ethnicities can be affected, but TPP is most prevalent in people of Asian and, secondly, Latin American descent. TPP is characterized by hypokalemia, suppressed TSH levels and increased levels of thyroid hormones. Nonselective β adrenergic blockers, such as propranolol, are an efficient adjuvant to antithyroid drugs to prevent paralysis; however, an early and definitive treatment should always be pursued. Evidence indicates that TPP results from the combination of genetic susceptibility, thyrotoxicosis and environmental factors (such as a high-carbohydrate diet). We believe that excess T(3) modifies the insulin sensitivity of skeletal muscle and pancreatic β cells and thus alters potassium homeostasis, but only leads to a depolarization-induced acute loss of muscle excitability in patients with inherited ion channel mutations. An integrated etiopathophysiological model is proposed based on molecular findings and knowledge gained from long-term follow-up of patients with TPP.

Hypokalemic thyrotoxic periodic paralysis with thyrotoxic psychosis and hypercapnic respiratory failure

Thyrotoxic periodic paralysis is a rare and potentially lethal neuromuscular disease that manifests as recurrent episodic muscle weakness associated with hypokalemia and thyrotoxicosis. Paralysis can rarely involve respiratory muscles leading to acute respiratory failure. The disease primarily affects people of Asian descent, but it is being increasingly reported in other ethnic groups. We review the literature and report a case of hypokalemic thyrotoxic periodic paralysis manifesting as thyroid storm with episodic acute respiratory failure requiring recurrent intubation and eventually requiring thyroidectomy for resolution of symptoms.

[Sex hormones and dry eye]

Among ophthalmic diseases dry eye in its various forms, represents an entity with one of the highest prevalences and at the same time the lowest chance for causal therapy. Since some years there is growing evidence that sex hormones play a key role in the formation and course of the disease and thus provide potentially promising approaches for therapy. The objective of this article is to briefly outline current scientific knowledge on the relationship between androgens, estrogens,and progesterones on the one hand and the lacrimal gland and Meibomian glands respectively.

Measurements of lacrimal glands from cadavers, with descriptions of typical glands and three gross variants

OBJECTIVE

To measure cadaveric human lacrimal glands.

METHODS

Excised lacrimal glands from 22 male and 23 female embalmed cadavers were stored in embalming fluid. They were then blotted, weighed, and measured using dividers and a digital micrometer.

RESULTS

Besides the typical gland (Type I), three gross variants were found. The subencapsulated variant (Type II) has dense connective tissue covering its deep surface. This would prevent the usual horizontal positioning of the lobes relative to the levator palpebrae superioris aponeurosis (lpsa), causing the latter to extend but minimally beneath the free edge of the orbital lobe. Consequently, the gland lies mainly beside the globe and angulated parallel to the lpsa. Its adjacent palpebral lobe lies beneath the latter. The bilayered variant (Type III) has its smaller orbital lobe's deep surface affixed above its large, ovoid palpebral lobe. Most of the gland droops beside the globe except for the edge of its orbital lobe which lies above the edge of the lpsa and beneath which the palpebral lobe's anteromedial portion lies. The macrovariant (Type IV) resembles the typical gland. However, between its big lobes is an unusually large gape for the lpsa.

CONCLUSIONS

Variant lacrimal glands are common (51.1%). Three types have been identified. The subencapsulated (26.7%) and bilayered (22.2%) types are the more common ones. Only one macrovariant (2.2%) specimen was found. Several dimorphisms exist in the typical and subencapsulated types, specimens from male cadavers being larger.

Sex hormone regulation of tear lipocalin in the rabbit lacrimal gland

Tear lipocalin (TL) (approximately 18 kDa), a member of the lipocalin superfamily, has been identified as one of the major proteins present in rabbit lacrimal fluid. The concentration of TL has been found to be decreased in the tears of patients with dry eye disease. Lacrimal gland insufficiency, one of the major causes of dry eye disease, is known to affect mainly postmenopausal women, where there is a significant decrease in the production of androgen and estrogen. These observations suggest that sex hormones might influence dry eye indirectly by regulating the expression of TL. The purpose of this study was to determine: (1) the effect of sexual maturation on the expression of TL; and (2) if the expression of TL is regulated by the estrogen, 17beta-estradiol, and/or the androgen, dihydrotestosterone, in sexually mature female rabbits. Lacrimal fluid (LF) and lacrimal gland soluble fraction (Si) was collected from juvenile (2 kg) and sexually mature (4 kg) male and female New Zealand white (NZW) rabbits. In addition, LF and Si were collected from 4 kg rabbits, 7 days after being either sham operated (control), ovariectomized (OVX), ovariectomized treated with estrogen (OVX+E) or ovariectomized treated with dihydrotestosterone (OVX+DHT). Samples were analyzed for protein levels of TL by SDS-PAGE and Western blotting using a polyclonal rat anti-rabbit TL antibody. Densitometry analysis showed that TL protein levels in both LF and Si increased with age in male and female rabbits. In addition, TL protein levels were significantly higher in the sexually mature 4 kg male compared with the 4 kg female, while no significant difference in TL protein levels were seen among the juvenile male and female rabbits. Furthermore, ovariectomy decreased the protein levels of TL in LF and Si fraction by 50% and 20% respectively, compared with control values. Estrogen treatment increased TL protein levels by 30% and 50% in the LF and Si fraction respectively, compared with the sham operated group. DHT treatment also increased TL protein levels by approximately 150% in both LF and Si fraction compared with control values. These results support the hypothesis that sex hormones influence TL protein levels in rabbit lacrimal glands. The possibility of a role of TL in dry eye needs to be further investigated.

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.

Traffic of endogenous, transduced, and endocytosed prolactin in rabbit lacrimal acinar cells

The rabbit lacrimal gland undergoes an immunophysiological transformation during pregnancy, reminiscent of that of the mammary gland as it prepares to deliver secretory IgA into the nascent fluid product. The contents of TGF-beta and prolactin (PRL) within ductal epithelial cells increase, and their primary localizations shift from the apical to the basal cytoplasm, suggesting a transformation from exocrine to paracrine secretion. Studies with ex vivo acinar cell models demonstrated that elevated PRL suppresses traffic of secretory proteins into the regulated exocrine apparatus and directs them into a novel, induced, regulated paracrine apparatus [Wang, Y., Chiu, C.T., Nakamura, T., Walker, A.M., Petridou, B., Trousdale M.D., Hamm-Alvarez S.F., Schechter J.E., Mircheff A.K., 2007. Elevated prolactin redirects secretory vesicle traffic in rabbit lacrimal acinar cells. Am. J. Physiol. Endocrinol. Metab. 292, E1122-E1134]. However, it was not clear whether PRL itself entered the induced paracrine apparatus. In the present study, confocal immunofluorescence microscopy revealed that natively expressed PRL and over-expressed PRL co-localized with PRL receptors (PRLR); rab11, a marker for the recycling endosome; gamma-adaptin, a marker for the Golgi complex and trans-Golgi network; and rab7, a marker for the autophagic lysosomal apparatus. Natively expressed, over-expressed, and endocytosed PRL also co-localized with rab4 and rab5A, markers for the early endosome, and with rab3D, a marker for regulated exocrine secretory vesicles. Endocytosed PRL was stored in intact form and released in response to stimulation with carbachol. Subcellular fractionation analysis detected relative excesses of PRL over PRLR in fractions that contained fragments of the recycling endosome and fractions that contained both secretory vesicle fragments and prelysosomal and autolysosomal fragments. EM-gold microscopy demonstrated PRL within small vesicles, consistent with endosomes or secondary lysosomes, and in large vesicles, consistent with regulated secretory vesicles. The secretory vesicles were preponderantly localized in the apical cytoplasm of control cells, and in the basal cytoplasm of PRL over-expressing cells. These results indicate that when lacrimal epithelial cells synthesize PRL, and when they endocytose it from their ambient medium, they traffic it both into the endosomes that constitute the constitutive transcytotic paracrine apparatus and also into regulated secretory vesicles, which are associated with the exocrine apparatus at low PRL levels and with the induced paracrine apparatus at high PRL levels.

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.

Elevated prolactin redirects secretory vesicle traffic in rabbit lacrimal acinar cells

During pregnancy, lymphocytes infiltrating the rabbit lacrimal gland disperse to the interacinar space from their normal focal concentrations, basal fluid secretion decreases, pilocarpine-induced fluid secretion increases, and stimulated fluid protein concentration decreases. Ductal epithelial cell prolactin (PRL) content increases and redistributes from the apical to the basal-lateral cytoplasm. A replication-incompetent adenovirus vector for rabbit PRL (AdPRL) was used to test the hypothesis that increased intracrine/autocrine PRL signaling alters secretory protein traffic in an ex vivo lacrimal acinar cell model. AdPRL had no discernable influence on microtubules or actin microfilaments or their responses to carbachol (CCh). Endogenous and transduced PRLs exhibited similar, nonpolarized, punctate distributions. Cells secreted PRL consititutively and at increased rates in response to CCh. In contrast, constitutive secretion of beta-hexosaminidase was negligible, suggesting that the constitutive pathway for PRL is relatively inaccessible to typical secretory proteins. AdPRL had no significant effect on total secretion of beta-hexosaminidase or syncollin-green fluorescent protein (GFP), a chimeric secretory protein construct. However, it reversed the polarized distributions of vesicles containing rab3D and syncollin-GFP. Live-cell imaging indicated that AdPRL redirected CCh-dependent syncollin-GFP exocytosis from the apical plasma membrane to the basal-lateral membrane. Elevated concentrations of exogenous rabbit PRL in the ambient medium elicited similar changes. These observations suggest that elevated PRL, as occurs in the physiological hyperprolactinemia of pregnancy, induces lacrimal epithelial cells to express a mixed exocrine/endocrine phenotype that secretes fluid to the acinus-duct lumen but secretes proteins to the underlying tissue space. This phenotype may contribute to the pregnancy-associated immunoarchitecture.

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.

The healing effects of crying

How does crying improve and enhance the emotional state? A personal, life-changing event experienced by the author helped postulate an answer to this question. This article explores tear production, crying across cultures and eras, the gender factor in tears and crying, and the author's ethnographic study of Pakistani men and women's views of crying in terms of its spiritual, cultural, and psychosomatic ramifications. Greater understanding of natural human emotions and the language of tears benefits the nursing profession and gives a better understanding of the phenomenon of crying.

Effect of inflammation on lacrimal gland function

The lacrimal gland is the main contributor to the aqueous layer of the tear film. It secretes proteins, electrolytes and water, which helps to nourish and protect the ocular surface. Lacrimal gland secretion is primarily under neural control, which is achieved through a neural reflex arc. Stimuli to the ocular surface activate afferent sensory nerves in the cornea and conjunctiva. This in turn activates efferent parasympathetic and sympathetic nerves in the lacrimal gland to stimulate secretion. Sex steroid hormones are also important regulators of lacrimal gland functions. A decrease or lack of lacrimal gland secretion is the leading cause of aqueous tear deficient dry eye syndrome (DES). It has been suggested that DES is an inflammatory disorder that affects the ocular surface and the lacrimal gland. In several pathological instances, the lacrimal gland can become a target of the immune system and show signs of inflammation. This can result from autoimmune diseases (Sjögren's syndrome), organ transplantation (graft versus host disease), or simply as a result of aging. The hallmarks of lacrimal gland inflammation are the presence of focal lymphocytic infiltrates and increased production of proinflammatory cytokines. The mechanisms leading to lacrimal gland dysfunction are still poorly understood. Apoptosis, production of autoantibodies, hormonal imbalance, alterations in signaling molecules, neural dysfunction, and increased levels of proinflammatory cytokines have been proposed as possible mediators of lacrimal gland insufficiency in disease states.

Mucosal Immunity and Self-Tolerance in the Ocular Surface System

This paper articulates a new working hypothesis that explains many of the pathophysiological conditions described under the common rubric "dry eye" as altered states of mucosal immune regulation. A central principle of mucosal immune physiology is that the parenchymal tissues at the effector sites, i.e., the sites at which secretory antibodies are produced, maintain local signaling milieus that support differentiation of IgA+ plasmablasts and survival of IgA+ plasmacytes. These local signaling milieus also support robust regulatory networks that maintain tolerance to commensual microbes, benign antigens, and parenchymal autoantigens. The regulatory networks are mediated by cycles of interactions between successive generations of dendritic cells, which normally mature with tolerogenic functions, and regulatory T cells, which normally reinforce the system's ability to generate new tolerogenic dendritic cells. The systemic endocrine environment controls expression of the local signaling milieu in the mammary gland and in the prostate and male urethral glands. Emerging evidence indicates that the local signaling milieu in the lacrimal gland also is determined, in part, by the systemic endocrine environment. This working hypothesis suggests explanations for the excess incidence of Sjogren syndrome among women and for the mechanisms of several different immunophysiological states in addition to Sjogren syndrome that, like Sjogren syndrome, are associated with the classical symptoms and signs of dry eye. It also comprises a promising rationale for specific new approaches to therapy.

Doppler sonography of the normal lacrimal gland

PURPOSE

We used Doppler sonography to determine the resistance index (RI) and pulsatility index (PI) of the normal lacrimal artery (LA) in both females and males. We also compared the values obtained at various periods of reproductive life.

METHODS

The study was performed in 25 prepubertal girls, 28 females of reproductive age, and 27 postmenopausal women, 23 pregnant women, and 104 healthy males. Doppler sonography was used to determine the RI and PI of the LA.

RESULTS

The mean PI for the entire patient population was 1.48 +/- 0.60 and the RI was 0.72 +/- 0.09. The RI and PI values of the LA did not differ between males and females. Similarly, the mean RI and PI values of the LA did not change significantly between the various reproductive phases.

CONCLUSION

The PI and RI of the lacrimal gland are similar in both sexes. Moreover, they are not altered by changes in levels of sex steroids.

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 effects of hormone replacement therapy on ocular surface and tear function tests in postmenopausal women

PURPOSE

To prospectively investigate the impact of various hormone replacement therapies (HRT) on ocular surface and tear function tests.

METHODS

A total of 70 women in the postmenopausal period were enrolled in the study. The groups consisted of 16 women who were not on HRT (group 1), 29 women who were on HRT with tibolone (group 2) and 25 women who received estradiol plus medroxyprogesterone acetate treatment (group 3). All patients underwent tear film break-up time (TFBUT), Schirmer's test and conjunctiva cytology at the time of enrollment and at 6 months' follow-up.

RESULTS

Patients in group 2 showed improved Schirmer's test and TFBUT results (p < 0.001); however, no significant changes occurred in group 1 and group 3 patients (p > 0.05). Conjunctival cytology scores did not differ at the time of enrollment and at 6 months' follow-up in all groups.

CONCLUSIONS

This is the first comparative clinical study on the effects of tibolone and estradiol plus medroxyprogesterone acetate on ocular surface and tear function tests. HRT with tibolone seems to improve tear function tests in postmenopausal women.

[Dry eye disease as a complex dysregulation of the functional anatomy of the ocular surface. New concepts for understanding dry eye disease]

INTRODUCTION

Dry eye disease is a disorder of the tear film that results in epithelial damage and in a disruption of the normal homeostasis at the ocular surface. It is widespread and causes symptoms ranging from discomfort to blindness.

METHODS

A review of the existing literature was used to compare different past and recent concepts for the understanding of dry eye disease with a focus on aspects of the integrating functional anatomy of the ocular surface.

RESULTS

The understanding of the pathogenesis of dry eye disease has proceeded from the mere recognition of a lack of tears to a consideration of their quality and to the concept of wetting of the ocular surface. However, several other aspects as epithelial differentiation, innervation, hormonal status or immune protection contribute to the intact functional anatomy of the ocular surface. Recently it has been recognized that immunologically regulated mechanisms of inflammation represent a primary or secondary pathogenetic factor for dry eye disease. This is conceivably regulated by the cells of the physiological mucosal immune defence system, the eye-associated lymphoid tissue (EALT). Androgens represent an important trophic factor for the ocular surface and their deficiency predisposes to inflammation.

CONCLUSION

Dry eye disease represents a complex dysregulation of the functional anatomy of the ocular surface that can start from different alterations (e.g. insufficient secretion, defects in wetting or innervation). Immune-based inflammation is able to interconnect and negatively reinforce these different pathomechanisms, resulting in a vicious circle.

Interactions of testosterone and all-trans retinoic acid in regulation of androgen receptor expression in rat lacrimal gland

All-trans retinoic acid down-regulates androgen receptor (AR) expression in lacrimal gland acinar cells in culture. The goal of this study was to determine if retinoic acid inhibits androgen-stimulated up-regulation of AR protein and AR mRNA expression in lacrimal glands of orchiectomized rats in vivo. Delivery of androgens to orchiectomized rats was accomplished by subcutaneous implantation of a 25 or 50 mg 21-day slow-release testosterone pellet. Rats were treated with retinoic acid by gastric gavage at 20 mg kg(-1) day(-1). After 7 days of treatment lacrimal glands were removed, AR protein expression in frozen sections was determined by immunohistochemistry and total RNA was probed for AR mRNA expression. Serum testosterone was measured by ELISA and serum retinoic acid was detected by HPLC. Orchiectomy decreases serum testosterone to 17 +/- 8 ng dl(-1), compared to 143 +/- 27 ng dl(-1) in normal rats, and reduces the number of lacrimal acinar cell nuclei expressing ARs to less than 30% of normal. Implantation of testosterone pellets restored lacrimal AR expression, but increased serum testosterone to more than 10 times the normal levels. Retinoic acid failed to inhibit AR expression in rats with high serum testosterone. Therefore a dose-response study was conducted in which testosterone was delivered by injection of a single dose of Depotestosterone at 2.5-200 mg kg(-1). Treatment of orchiectomized rats with a dose of testosterone as low as 2.5 mg kg(-1) resulted in serum testosterone levels of 62 +/- 17 ng dl(-1) and significantly increased lacrimal gland AR expression. Delivery of retinoic acid at 20 or 50 mg kg(-1) day(-1) simultaneously with a 2.5 mg kg(-1) testosterone injection prevented restoration of lacrimal gland AR expression and significantly reduced AR mRNA expression. A pharmacologic dose of retinoic acid inhibits AR expression in lacrimal gland acinar cells in vivo, as well as in vitro. This indicates that effects of retinoic acid and testosterone are antagonistic and suggests that retinoic acid may modulate effects of testosterone on the lacrimal gland.

Estrogen prevention of lacrimal gland cell death and lymphocytic infiltration

Previous studies have shown that ovariectomy causes necrosis of lacrimal acinar cells, apoptosis of plasma cells and gland lymphocytic infiltration. Both, lacrimal gland cell death and lymphocytic infiltration were prevented by androgen treatment. Since estrogens are removed by ovariectomy, and the synthetic estrogen diethylstilbestrol has been shown to affect some biochemical correlates of lacrimal secretion, the purpose of this study was to determine the effect of 17-beta-estradiol treatment on ovariectomy-induced cell death and lymphocytic infiltration. Sexually mature female New Zealand white rabbits (4-4.5 kg) were ovariectomized and divided into two groups. One group was treated with 0.5 mg kg(-1) per day 17-beta-estradiol, and the other group with vehicle alone. A third group of sham operated rabbits was used as controls and they also were treated with vehicle alone. Six days after surgery, the animals were euthanized, the lacrimal glands removed and processed for analysis of apoptosis as assessed by DNA fragmentation, and for morphological examination. DNA fragmentation was determined using the TUNEL assay and agarose gel electrophoresis. Sections were also stained for rabbit thymic lymphocyte antigen (RTLA), and rabbit CD18. Labelled nuclei and stained areas were quantified by automated densitometry. Ovariectomized rabbits showed a significant increase in the values for degraded DNA as a percent of total nuclear area (2.90+/-0.40%) compared to sham operated rabbits (0.73+/-0.22%). 17-beta-estradiol treatment in ovariectomized rabbits prevented the increase in DNA degradation. Examination of TUNEL assay at higher magnification (40x) confirmed previous studies showing that ovariectomy caused apoptosis of interstitial cells. Significant numbers of bulging cells of very pale appearance under light microscopy, also confirm previously identified necrotic cells in acinar regions. Treatment with 17-beta-estradiol prevented this necrosis. Increased numbers of RTLA(+) and CD18(+) interstitial cells were also evident after ovariectomy. 17-beta-estradiol treatment prevented the increase in the number of lymphoid cells. We confirmed previous observations that suggest that glandular atrophy observed after ovariectomy is likely to proceed by necrosis of acinar cells rather than apoptosis, and that ovariectomy triggers an inflammatory response in the gland. These results suggest that in addition to androgens, estrogens also seem to play a role to maintain lacrimal gland structure and function. A decrease in available estrogen levels could trigger both lacrimal gland apoptosis and necrosis, as well as lymphocytic infiltration. Although, the effect of estrogens in these experiments seems to be direct and not through androgens, the possibility of the role of an autocrine and/or paracrine factors, promoted by estrogen on lacrimal gland cells still needs to be investigated.

Is complete androgen insensitivity syndrome associated with alterations in the meibomian gland and ocular surface?

PURPOSE

This study's purpose was to determine whether complete androgen insensitivity syndrome (CAIS) is associated with alterations in the meibomian gland and ocular surface.

METHODS

Individuals with CAIS, as well as age-matched female and male controls, completed questionnaires which assessed dry eye symptoms and underwent slit lamp evaluations of the tear film, tear meniscus, lids and lid margins and conjunctiva. The quality of meibomian gland secretions was also analyzed.

RESULTS

Our results demonstrate that CAIS is associated with meibomian gland alterations and a significant increase in dry eye signs and symptoms. Clinical assessment revealed that CAIS women, as compared to controls, had a significant increase in telangiectasia, keratinization, lid erythema and orifice metaplasia of the meibomian glands, and a significant decrease in the tear meniscus and quality of meibomian gland secretions. Questionnaire results showed that dry eye symptoms were increased over twofold in CAIS individuals, as compared to controls, including a significant increase in the sensations of dryness, pain and light sensitivity.

CONCLUSION

Our results suggest that androgen insensitivity may promote meibomian gland dysfunction and an increase in the signs and symptoms of dry eye.