Dihydrotestosterone suppression of proinflammatory gene expression in human meibomian gland epithelial cells.

PURPOSE: We discovered that dihydrotestosterone (DHT) decreases the ability of lipopolysaccharide, a bacterial toxin, to stimulate the secretion of leukotriene B4, a potent proinflammatory mediator, by immortalized human meibomian gland epithelial cells (IHMGECs). We hypothesize that this hormone action reflects an androgen suppression of proinflammatory gene activity in these cells. Our goal was to test this hypothesis. For comparison, we also examined whether DHT treatment elicits the same effect in immortalized human corneal (IHC) and conjunctival (IHConj) ECs. METHODS: Differentiated cells were cultured in media containing vehicle or 10 nM DHT. Cells (n = 3 wells/treatment group) were then processed for RNA isolation and the analysis of gene expression by using Illumina BeadChips, background subtraction, cubic spline normalization and Geospiza software. RESULTS: Our results demonstrate that DHT significantly suppressed the expression of numerous immune-related genes in HMGECs, such as those associated with antigen processing and presentation, innate and adaptive immune responses, chemotaxis, and cytokine production. DHT also enhanced the expression of genes for defensin ß1, IL-1 receptor antagonist, and the anti-inflammatory serine peptidase inhibitor, Kazal type 5. In contrast, DHT had no effect on proinflammatory gene expression in HCECs, and significantly increased 33 gene ontologies linked to the immune system in HConjECs. CONCLUSIONS: Our findings support our hypothesis that androgens suppress proinflammatory gene expression in IHMGECs. This hormone effect may contribute to the typical absence of inflammation within the human meibomian gland.

Case Series: Cancer-Related Facial Pain Treated with Stellate Ganglion Block.

Stellate ganglion block (SGB) is believed to modify the pathologic sympathetic pain response and has been commonly used to treat complex regional pain syndrome. We report successful treatment of cancer-related facial pain with SGB in three patients, suggesting a possible sympathetic pain-related mechanism. All patients exhibited clinically significant improvement of pain 12 weeks following the procedure. SGB should be considered a palliative pain treatment option in cancer-related facial pain.

Are BALB/c Mice Relevant Models for Understanding Sex-Related Differences in Gene Expression in the Human Meibomian Gland?

BACKGROUND: A compelling feature of dry eye disease is that it occurs predominantly in women. We hypothesize that this female prevalence is linked to sex-related differences in the meibomian gland (MG). This gland plays a critical role in maintaining the tear film, and its dysfunction is a major cause of dry eye disease. To understand the factors that underlie MG sexual dimorphism and promote dry eye in women, we seek to identify an optimal model for the human MG. Our goal was to determine whether a murine MG is such a model. Toward that end, we examined whether sex differences in MG gene expression are the same in BALB/c mice and humans. METHODS: Eyelid tissues were collected from humans (n = 5-7/sex) and BALB/c mice (n = 9/sex). MGs were isolated and processed for the evaluation of gene expression by using microarrays and bioinformatics software. RESULTS: Our analysis of the 500 most highly expressed genes from human and mouse MGs showed that only 24.4% were the same. Our comparison of 100 genes with the greatest sex-associated differences in human and mouse MGs demonstrated that none were the same. Sex also exerted a significant impact on numerous ontologies, Kyoto Encyclopedia of Genes and Genomes pathways, and chromosomes, but these effects were primarily species-specific. CONCLUSIONS: Our results indicate that BALB/c mice are not optimal models for understanding sex-related differences in gene expression of the human MG.

Influence of lipopolysaccharide on proinflammatory gene expression in human corneal, conjunctival and meibomian gland epithelial cells.

PURPOSE: Lipopolysaccharide (LPS), a bacterial endotoxin, is known to stimulate leuokotriene B4 (LTB4) secretion by human corneal (HCECs), conjunctival (HConjECs) and meibomian gland (HMGECs) epithelial cells. We hypothesize that this LTB4 effect represents an overall induction of proinflammatory gene expression in these cells. Our objective was to test this hypothesis. METHODS: Immortalized HCECs, HConjECs and HMGECs were cultured in the presence or absence of LPS (15 µg/ml) and ligand binding protein (LBP; 150 ng/ml). Cells were then processed for RNA isolation and the analysis of gene expression by using Illumina BeadChips, background subtraction, cubic spline normalization and GeneSifter software. RESULTS: Our findings show that LPS induces a striking increase in proinflammatory gene expression in HCECs and HConjECs. These cellular reactions are associated with a significant up-regulation of genes associated with inflammatory and immune responses (e.g. IL-1ß, IL-8, and tumor necrosis factor), including those related to chemokine and Toll-like receptor signaling pathways, cytokine-cytokine receptor interactions, and chemotaxis. In contrast, with the exception of Toll-like signaling and associated innate immunity pathways, almost no proinflammatory ontologies were upregulated by LPS in HMGECs. CONCLUSIONS: Our results support our hypothesis that LPS stimulates proinflammatory gene expression in HCECs and HConjECs. However, our findings also show that LPS does not elicit such proinflammatory responses in HMGECs.

A novel revision to the classical transnasal topical sphenopalatine ganglion block for the treatment of headache and facial pain.

BACKGROUND: The sphenopalatine ganglion (SPG) is located with some degree of variability near the tail or posterior aspect of the middle nasal turbinate. The SPG has been implicated as a strategic target in the treatment of various headache and facial pain conditions, some of which are featured in this manuscript. Interventions for blocking the SPG range from minimally to highly invasive procedures often associated with great cost and unfavorable risk profiles. OBJECTIVE: The purpose of this pilot study was to present a novel, FDA-cleared medication delivery device, the Tx360® nasal applicator, incorporating a transnasal needleless topical approach for SPG blocks. This study features the technical aspects of this new device and presents some limited clinical experience observed in a small series of head and face pain cases. STUDY DESIGN: Case series. SETTINGS: Pain management center, part of teaching-community hospital, major metropolitan city, United States. METHODS: After Institutional Review Board (IRB) approval, the technical aspects of this technique were examined on 3 patients presenting with various head and face pain conditions including trigeminal neuralgia (TN), chronic migraine headache (CM), and post-herpetic neuralgia (PHN). The subsequent response to treatment and quality of life was quantified using the following tools: the 11-point Numeric Rating Scale (NRS), Modified Brief Pain Inventory - short form (MBPI-sf), Patient Global Impression of Change (PGIC), and patient satisfaction surveys. The Tx360® nasal applicator was used to deliver 0.5 mL of ropivacaine 0.5% and 2 mg of dexamethasone for SPG block. Post-procedural assessments were repeated at 15 and 30 minutes, and on days one, 7, 14, and 21 with a final assessment at 28 days post-treatment. All patients were followed for one year. Individual patients received up to 10 SPG blocks, as clinically indicated, after the initial 28 days. RESULTS: Three women, ages 43, 18, and 15, presented with a variety of headache and face pain disorders including TN, CM, and PHN. All patients reported significant pain relief within the first 15 minutes post-treatment. A high degree of pain relief was sustained throughout the 28 day follow-up period for 2 of the 3 study participants. All 3 patients reported a high degree of satisfaction with this procedure. One patient developed minimal bleeding from the nose immediately post-treatment which resolved spontaneously in less than 5 minutes. Longer term follow-up (up to one year) demonstrated that additional SPG blocks over time provided a higher degree and longer lasting pain relief. LIMITATIONS: Controlled double blind studies with a higher number of patients are needed to prove efficacy of this minimally invasive technique for SPG block. CONCLUSION: SPG block with the Tx360® is a rapid, safe, easy, and reliable technique to accurately deliver topical transnasal analgesics to the area of mucosa associated with the SPG. This intervention can be delivered in as little as 10 seconds with the novice provider developing proficiency very quickly. Further investigation is certainly warranted related to technique efficacy, especially studies comparing efficacy of Tx360 and standard cotton swab techniques.

Transcription, translation, and function of lubricin, a boundary lubricant, at the ocular surface.

IMPORTANCE: Lubricin may be an important barrier to the development of corneal and conjunctival epitheliopathies that may occur in dry eye disease and contact lens wear. OBJECTIVE: To test the hypotheses that lubricin (ie, proteoglycan 4 [PRG4 ]), a boundary lubricant, is produced by ocular surface epithelia and acts to protect the cornea and conjunctiva against significant shear forces generated during an eyelid blink and that lubricin deficiency increases shear stress on the ocular surface and promotes corneal damage. DESIGN, SETTING, AND PARTICIPANTS: Human, porcine, and mouse tissues and cells were processed for molecular biological, immunohistochemical, and tribological studies, and wild-type and PRG4 knockout mice were evaluated for corneal damage. RESULTS: Our findings demonstrate that lubricin is transcribed and translated by corneal and conjunctival epithelial cells. Lubricin messenger RNA is also present in lacrimal and meibomian glands, as well as in a number of other tissues. Absence of lubricin in PRG4 knockout mice is associated with a significant increase in corneal fluorescein staining. Our studies also show that lubricin functions as an effective friction-lowering boundary lubricant at the human cornea-eyelid interface. This effect is specific and cannot be duplicated by the use of hyaluronate or bovine serum albumin solutions. CONCLUSIONS AND RELEVANCE: Our results show that lubricin is transcribed, translated, and expressed by ocular surface epithelia. Moreover, our findings demonstrate that lubricin presence significantly reduces friction between the cornea and conjunctiva and that lubricin deficiency may play a role in promoting corneal damage.

Influence of aromatase absence on the gene expression and histology of the mouse meibomian gland.

PURPOSE: We hypothesize that aromatase, an enzyme that controls estrogen biosynthesis, plays a major role in the sex-related differences of the meibomian gland. To begin to test this hypothesis, we examined the influence of aromatase absence, which completely eliminates estrogen production, on glandular gene expression and histology in male and female mice. METHODS: Meibomian glands were obtained from adult, age-matched wild-type (WT) and aromatase knockout (ArKO) mice. Tissues were processed for histology or the isolation of total RNA, which was analyzed for differentially expressed mRNAs by using microarrays. RESULTS: Our results show that aromatase significantly influences the expression of more than a thousand genes in the meibomian gland. The nature of this effect is primarily sex-dependent. In addition, the influence of aromatase on sex-related differences in gene expression is predominantly genotype-specific. However, many of the sex-related variations in biological process, molecular function, and cellular component ontologies, as well as in KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways, are remarkably similar between WT and ArKO mice. The loss of aromatase activity has no obvious effect on the histology of meibomian glands in male or female mice. CONCLUSIONS: Our findings demonstrate that aromatase has a significant impact on gene expression in the meibomian gland. The nature of this influence is sex-dependent and genotype-specific; however, many of the sex-related variations in gene ontologies and KEGG pathways are similar between WT and ArKO mice. Consequently, it appears that aromatase, and by extension estrogen, do not play a major role in the sex-related differences of the mouse meibomian gland.

Regulation of leukotriene B4 secretion by human corneal, conjunctival, and meibomian gland epithelial cells.

OBJECTIVES: To test the hypotheses that lipopolysaccharide (LPS) stimulates leukotriene B4 (LTB4) production in human ocular surface and adenexal cells, arachidonic acid duplicates the stimulatory effect of LPS, LPS-binding protein potentiates LPS-induced LTB4 secretion, and dihydrotestosterone attenuates the immune effect of LPS. METHODS: Immortalized human corneal, conjunctival, and meibomian gland epithelial cells were cultured in the presence or absence of fetal bovine serum and were exposed to vehicle, LPS, LPS plus LPS-binding protein, arachidonic acid, or dihydrotestosterone. Culture media were processed for the LTB4 analysis. RESULTS: Lipopolysaccharide stimulates time-dependent secretion of LTB4 by human corneal, conjunctival, and meibomian gland epithelial cells. This effect, which we could not detect with arachidonic acid, is potentiated by exposure to LPS-binding protein. This potentiation, in turn, is significantly reduced by cellular treatment with dihydrotestosterone. CONCLUSIONS: Ocular epithelial cells have the ability to generate LTB4 in response to LPS exposure. This proinflammatory process is modulated by LPS-binding protein and by dihydrotestosterone. CLINICAL RELEVANCE: When induced by appropriate stimuli, LTB4 production may have a role in the generation of inflammation in ocular surface disease.