Masafumi Ono

Sodium hyaluronate eyedrops in the treatment of dry eyes.

BACKGROUND--Several studies in the past have attempted to demonstrate the efficacy of sodium hyaluronate in the treatment of dry eyes. However, results have been conflicting and a definite conclusion has not yet been reached. This study recruited a larger group of patients and has incorporated for the first time both fluorescein and rose bengal staining in the evaluation of the epithelium. METHODS--Eighteen albino rabbit corneas were used in a basic animal study to demonstrate the efficacy of sodium hyaluronate by comparing the effects on the rate of epithelial healing. The optimal concentration to be used in the clinical trial was determined from the results of the basic study. In the clinical study 104 patients with dry eye syndrome were enrolled in a double masked controlled clinical trial. Patients received sodium hyaluronate drops in one eye and control medication in the other eye for 4 weeks. Grading of subjective symptoms and clinical examinations were performed at 2 and 4 weeks. RESULTS--In the animal study sodium hyaluronate at concentrations of 0.1% and 0.5% significantly accelerated the recovery time of iodine vapour induced corneal erosions (p < 0.01). In the clinical study no statistical significance was observed in the improvement of subjective symptoms or rose bengal staining, while fluorescein scores significantly improved in eyes receiving sodium hyaluronate (p = 0.0001) at 4 weeks. CONCLUSION--Sodium hyaluronate drops applied in six daily doses could not be demonstrated to offer advantages over conventional tear supplies in the improvement of subjective symptoms, but may play a role in maintaining a healthy corneal epithelium.

Androgens and Dry Eye in Sjögren's Syndromea

ABSTRACT: Sjögrens syndrome is an extremely complex and currently incurable autoimmune disorder, which occurs primarily in females, and is associated with lacrimal gland inflammation, meibomian gland dysfunction, and severe dry eye. We hypothesize that androgen deficiency, which reportedly occurs in primary and secondary Sjögrens syndrome (e.g., systemic lupus erythematosus, rheumatoid arthritis), is a critical etiologic factor in the pathogenesis of dry eye syndromes. We further hypothesize that androgen treatment to the ocular surface will promote both lacrimal and meibomian gland function and alleviate both “aqueous‐deficient” and “evaporative” dry eye. Our results demonstrate that androgens regulate both lacrimal and meibomian gland function, and suggest that topical androgen administration may serve as a safe and effective therapy for the treatment of dry eye in Sjögrens syndrome.

Influence of gender and the endocrine environment on the distribution of androgen receptors in the lacrimal gland

Androgens are known to regulate both the structure and function of lacrimal tissue in a variety of species. To explore the endocrine basis for this hormone action, the following study was designed to: (1) determine the cellular distribution of androgen receptors in the lacrimal gland; and (2) examine the influence of gender and the endocrine environment on the glandular content of these binding sites. Lacrimal glands were obtained from intact, castrated, hypophysectomized, diabetic or sham-operated male or female adult rats, mice or hamsters, as well as from orchiectomized rats exposed to placebo compounds or physiological levels of testosterone. The cellular location of androgen receptors was evaluated by utilizing an immunoperoxidase protocol, in which a purified rabbit polyclonal antibody to the rat androgen receptor was used as the first antibody. Our findings with lacrimal glands showed that: (1) androgen receptors are located almost exclusively in nuclei of epithelial cells; (2) the cellular distribution or intranuclear density of these binding sites is far more extensive in glands of males, as compared to females; (3) orchiectomy or hypophysectomy, but not sham-surgery or diabetes, lead to a dramatic reduction in the immunocytochemical expression of androgen receptors; and (4) testosterone administration to orchiectomized rats induces a marked increase in androgen receptor content, relative to that in placebo-exposed glands. Our results also reveal that a 10 kb androgen receptor mRNA exists in the rat lacrimal gland. Overall, these findings demonstrate that gender and the endocrine system may significantly influence the distribution of androgen binding sites in rat lacrimal tissue. Moreover, our results show that androgens up-regulate their own lacrimal gland receptors.

Identification and endocrine control of sex steroid binding sites in the lacrimal gland

Previous research has indicated that the lacrimal gland may be a target organ for sex steroids and that androgen effects on this tissue may be inhibited by pituitary deficiency or diabetes. To extend these findings, the objectives of the current investigation were 3-fold: [a] to determine whether specific and high-affinity binding sites for androgens and estrogens exist in rat lacrimal tissue; [b] to assess whether the number and affinity of androgen binding sites in the lacrimal gland may be influenced by hypophysectomy or acute diabetes; and [c] to examine whether androgen receptor mRNA may be detected in lacrimal tissues of a variety of species. Following the collection of lacrimal gland samples, tissues were processed for the conduct of equilibrium binding methods or molecular biological techniques. Our results demonstrated that a single class of saturable, high-affinity and stereochemically selective binding sites for androgens exist in lacrimal tissues of male and female rats. These sites possessed a dissociation constant of approximately 1 nM and were also present in isolated acinar epithelial cells. In contrast, we were unable to find any evidence for the presence of specific or high-affinity receptors for estrogens in the rat lacrimal gland. With regard to changes in the endocrine environment, hypophysectomy led to an increase in the number and affinity of androgen binding sites in rat lacrimal tissue cytosol, whereas diabetes reduced the total quantity of these sites. Of interest, androgen receptor mRNA was detected in lacrimal glands of mice, rats, hamsters, guinea pigs, rabbits and humans. Overall, our findings show that the lacrimal gland is a target organ for androgens and that androgen action in this tissue may be mediated through an interaction with specific and high-affinity binding sites.

Possible Involvement of EBV-Mediated α-Fodrin Cleavage for Organ-Specific Autoantigen in Sjogren’s Syndrome

A cleavage product of α-fodrin may be an important organ-specific autoantigen in the pathogenesis of Sjogren’s syndrome (SS), but the mechanisms of α-fodrin cleavage remain unclear. Since EBV has been implicated in the pathogenesis of SS, we determined whether EBV activation could induce the SS-specific 120-kDa autoantigen α-fodrin. ZEBRA mRNA expression, a marker for activation of the lytic cycle of EBV, was found in the salivary gland tissues from SS patients, but not in those from control individuals. ZEBRA-expressing lymphoid cells were also found in the SS glands in double-stained immunohistochemistry. Furthermore, a significant link between production of Abs against 120-kDa α-fodrin and reactivated EBV Ag was found in sera from patients with SS, but not in those from control individuals. EBV-activated lymphoid cells showed specific α-fodrin cleavage to the expected 120-kDa fragments in vitro. Pretreatment with caspase inhibitors inhibited cleavage of α-fodrin. Thus, an increase in apoptotic protease activities induced by EBV reactivation may be involved in the progression of α-fodrin proteolysis in the development of SS.

Immunocytochemical location and hormonal control of androgen receptors in lacrimal tissues of the female MRL/Mp-lpr/lpr mouse model of Sjögren's syndrome

Androgen therapy suppresses lymphocyte infiltration in, and improves the functional activity of, lacrimal glands in a female mouse model (MRL/Mp-lpr/lpr [MRL/lpr]) of Sjögrens syndrome. To extend these findings, the current investigation was designed to identify the cellular target(s) within lacrimal tissue that may mediate this androgen effect. In addition, we explored the endocrine regulation of androgen receptors in autoimmune lacrimal glands. Adult, female MRL/lpr mice were exposed systemically to vehicle, steroid hormones or immunosuppressive agents for varying time intervals after the onset of disease. Immediately before or after treatment, lacrimal glands were obtained and processed to determine the cellular distribution and nuclear density of androgen receptors by immunoperoxidase and image analysis techniques. Our findings demonstrated that: (1) androgen receptors exist almost exclusively within nuclei of acinar and ductal epithelial cells in lacrimal tissue of MRL/lpr mice; (2) androgen receptors are not detectable in the extensive lymphocytic populations that infiltrate the gland; (3) testosterone administration induces a significant increase in the number of androgen receptor-containing cells in, as well as the density of androgen receptors in epithelial cell nuclei of, lacrimal tissue; (4) hormone action is steroid-specific: administration of androgen analogues, but not estrogens, glucocorticoids or cyclophosphamide, stimulate the accumulation of androgen receptors; and (5) androgen receptor density is significantly reduced following the withdrawal of androgen therapy. These results show that epithelial cells, but not lymphocytes, are the androgen target cells in lacrimal tissue, and suggest that these cells may mediate the androgen-related immunosuppression and functional enhancement in lacrimal glands of autoimmune female mice. Our findings also demonstrate that androgens increase the expression of their own receptors in MRL/lpr lacrimal tissue.

Androgen-Induced Suppression of Autoimmune Disease in Lacrimal Glands of Mouse Models of Sjögren’s Syndrome

Almost 2,000 years ago, Claudius Galen, the Greek physician and writer, proposed that the mental status of an individual may significantly influence one’s susceptibility to disease.1 This postulate serves as an historic landmark in the rapidly growing field of neuroendocrinimmunology, which was established through the recognition that the nervous, endocrine and immune systems control each other through bidirectional channels of communication, that employ both similar signals and receptors.2–7 At present, over 50 neurotransmitters, hormones and secretagogues are known that exert a profound impact on cellular, humoral and mucosal immunity.2–7 However, the exact nature of these interactions is extremely dependent upon the specific signal, target cell, and local microenvironment.8 Thus, depending upon the tissue, neuroendocrine action may result in stimulation, inhibition, or no effect, on immune expression.8 As an additional consideration, antigenic exposure to the immune system may lead to the generation of numerous lymphocytic cytokines (e.g. lymphokines, neuropeptides, hormones), that directly regulate neural and endocrine function.2–7 In consequence, an extensive, triangular interrelationship exists among the neural, endocrine and immune systems that acts to promote homeostasis and health.

Binding Characteristics, Immunocytochemical Location and Hormonal Regulation of Androgen Receptors in Lacrimal Tissue

During the past five decades, researchers have found that distinct, gender-related differences exist in the morphology, histochemistry, biochemistry, immunology and molecular biology of the lacrimal gland in a variety of species, including mice, rats, guinea pigs, hamsters, rabbits and humans.1 These differences include striking variations in acinar cell characteristics (e.g. area, shape, membrane appearance, vesicle and nucleoli densities, nuclear size), lymphocyte populations, messenger RNA levels, enzyme and glycoprotein content, collagen amounts, adrenergic receptor expression, hormone responsiveness, and specific protein secretion.1 The underlying basis for this sexual dimorphism appears to be due almost entirely to the selective influence of androgens on the lacrimal gland.1 In contrast, sex steroids such as estrogens or progestins seem to have minimal, or no, direct effect on lacrimal tissue.1

Androgen Regulation of Ocular Mucosal- and Auto-Immunity

At present, it is known that androgens exert a tremendous impact on the development, expression and function of the immune system in both health and disease. In brief, these hormones have been shown to: [a] influence the maturation, proliferation and/or activity of pluripotent stem cells, B cells, T cells and macrophages; [b] modulate the synthesis, secretion and/or action of antibodies, cytokines and growth factors; [c] alter the production of autoantibodies and the formation of immune complexes; [d] affect the immune response to, and clearance of, antigens; [e] control the generation of thymic factors and secretory component (SC), the IgA antibody receptor; and [f] modify the rejection of allografts, the extent of graft vs. host disease, the magnitude of inflammation, and the onset and severity of autoimmune disease.e.g.1–6 The precise nature of these androgen actions is exceedingly dependent upon the specific target cell, the local microenvironment, and the particular immunological process, and may result in enhancement, inhibition, or no effect, on immune expression.3 Nevertheless, it is quite apparent that androgens control multiple aspects of humoral, cell-mediated, mucosal and auto-immunity.

Aldose reductase inhibition and the phosphorus-31 profile of the intact diabetic rat lens

Diabetic metabolic change and response to aldose reductase inhibition in the Wistar rat lens were examined with phosphorus-31 (31P) nuclear magnetic resonance (NMR) spectroscopy. To avoid artifacts in sample preparation, we used freshly excised lenses and acquired NMR data for 20 min immediately after lens extraction. The results showed a diabetes-induced time-dependent loss of ATP and phosphorylcholine (PC), an increase in alpha-glycerophosphate (alpha-GP) and inorganic phosphate and the appearance of sorbitol-3-phosphate (S-3-P) and fructose-3-phosphate (F-3-P). Oral but not topical dosing of an aldose reductase inhibitor, 5-(3-ethoxy-4-pentyloxyphenyl)-2,4- thiazolidinedione, resulted in a positive dose-response correlation characterized by a restoration of PC, S-3-P and F-3-P to the prediabetic level; however, alpha-GP and ATP were only partially normalized. The significance of the 31P change was further discussed.