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.

Background: Reinke crystals are structures pathognomonic for Leydig cells, which have the important function of testosterone production and are vital for male reproductive health. These crystalline inclusions are thought to be of protein origin; however, the molecular composition has not yet been resolved. Objectives:This review summarizes all available information regarding Reinke crystal's characteristics and aims to produce a comprehensive guide for research on this topic as well as to determine and discuss potential Reinke-protein candidates.Methods: Pubmed was thoroughly searched for all publications regarding Reinke crystals and 137 publications were identified. All publications were surveyed and all relevant information was included in the review.Results: Along with the cytoplasm, structures that resemble Reinke crystals were also observed in the nucleus, suggesting that their formation depends only on protein concentration. Variations in tissue processing protocols could impact Reinke crystal microscopic visualization, which is an important factor in diagnosing Leydig cell disorders such as Leydig cell tumors. Reinke crystals appear to be hallmarks of normally differentiated, adult, Leydig or Leydig-like cells in humans, while some abnormal and nonhuman Leydig cells contain Reinke-like paracrystalline inclusions or crystalloids.Conclusions: These characteristics point to some differentially expressed proteins, which could be involved in Reinke crystal formation. Differential Reinke crystal and paracrystalline inclusion presence could also be due to small changes in protein structure or the cell environment. Further research is needed to solve the ongoing mystery of the Reinke crystal, which would enhance our knowledge of Leydig cell contribution in the pathogenesis of various male reproductive disorders and improve their diagnosis and treatment.

No abstract