RESUMO

El ojo seco es una condición frecuente que tiene un impacto importante sobre la calidad de vida, pues conlleva a una sensación de incomodidad y discapacidad visual. Adicionalmente, puede tener un efecto pernicioso sobre procedimientos quirúrgicos oculares, lo que compromete el resultado de las cirugías de córnea, catarata y refractiva. Este síndrome de disfunción lagrimal es un padecimiento multifactorial, derivado de una deficiencia o evaporación excesiva de la lágrima. Se realizó una búsqueda en la literatura científica, con el objetivo de describir de forma general la enfermedad del ojo seco, brindando información actualizada en relación a su concepto, epidemiología, clasificación, factores de riesgo, fisiopatología, síntomas y signos, retos diagnósticos atendiendo a la complejidad de la entidad y tratamiento. La identificación temprana de los subtipos y el control de la severidad es crucial para mejorar el bienestar del paciente. La carga económica en la sociedad, y el impacto de la enfermedad en el individuo, a través de su efecto sobre la visión, calidad de vida y productividad laboral, así como en su esfera psicológica y física son considerables. Por ello, es importante que los oftalmólogos con el apoyo de los tecnólogos en optometría y óptica diagnostiquen y traten la enfermedad en sus fases iniciales, en la que los signos y síntomas todavía no son graves, lo que permitirá ralentizar su evolución natural, y posiblemente disminuir las consecuencias perjudiciales que provoca(AU)

Dry eye is a common condition that has a significant impact on quality of life, leading to a feeling of discomfort and visual impairment. Additionally, it can have a pernicious effect on ocular surgical procedures, compromising the outcome of corneal, cataract and refractive surgeries. This lacrimal dysfunction syndrome is a multifactorial condition, derived from a deficiency or excessive tear evaporation. A search of the scientific literature was carried out with the aim of describing dry eye disease in a general way, providing updated information regarding its concept, epidemiology, classification, risk factors, pathophysiology, symptoms and signs, diagnostic challenges considering the complexity of the condition and its treatment. Early identification of subtypes and control of severity is crucial to improve patient welfare. The economic burden on society, and the impact of the disease on the individual, through its effect on vision, quality of life and work productivity, as well as on the psychological and physical aspects, are considerable. Therefore, it is important that ophthalmologists with the support of optometrists and ophthalmic technologists diagnose and treat the disease in its early stages, when signs and symptoms are not yet severe, which will slow down its natural progression, and possibly reduce the resulting harmful consequences(AU)

Assuntos

RESUMO

The unfolded protein response (UPR) is a complex network of intracellular pathways that transmits signals from ER lumen and/or ER bilayer to the nuclear compartment in order to activate gene transcription. UPR is activated by the loss of ER capacities, known as ER stress, and occurs to restore ER properties. In this regard, glycerolipid (GL) synthesis activation contributes to ER membrane homeostasis and IRE1α-XBP1, one UPR pathway, has a main role in lipogenic genes transcription. Herein, we describe the strategy and methodology used to evaluate whether IRE1α-XBP1 pathway regulates lipid metabolism in renal epithelial cells subjected to hyperosmolar environment. XBP1s activity was hindered by blocking IRE1α RNAse activity and by impeding its expression; under these conditions, we determined GL synthesis and lipogenic enzymes expression.

Assuntos

RESUMO

We recently reported that an intact caveolar structure is necessary for adequate cell migration and tubulogenesis of the human extravillous trophoblast (EVT) cells. Emerging evidence supports that hyperosmolarity induces the internalization of caveolae into the cytoplasm and accelerates their turnover. Furthermore, signaling pathways associated with the regulation of trophoblast differentiation are localized in caveolae. We hypothesized that hyperosmolarity impairs EVT differentiation and caveolae/caveolin-1 (Cav-1) participates in this process. EVT cells (Swan 71 cell line) were cultured in complete Dulbecco's Modified Eagle Medium/Nutrient Mixture F-12 and exposed to hyperosmolar condition (generated by the addition of 100 mM sucrose). Hyperosmolarity altered the EVT cell migration and the formation of tube-like structures. In addition, cell invasion was decreased along with a reduction in the latent and active forms of matrix metalloproteinase-2 (MMP-2) secreted by these cells. With respect to Cav-1 protein abundance, we found that hyperosmolarity enhanced its degradation by the lysosomal pathway. Accordingly, in the hyperosmolar condition, we also observed a significant increase in the number of vacuoles and the internalization of the caveolae into the cytoplasm. Taken together, our findings suggest that hyperosmolarity may induce caveolae internalization and increase their turnover, compromising the normal differentiation of EVT cells.

RESUMO

Dry eye disease (DED) is a highly prevalent ocular surface disorder with neuroimmune pathophysiology. Tear hyperosmolarity (THO), a frequent finding in affected patients, is considered a key element in DED pathogenesis, yet existing animal models are based on subjecting the ocular surface to the more complex desiccating stress - decreased tear production and/or increased evaporation - instead of strict hyperosmolar stress. Here we characterized a murine model of THO that does not involve desiccating stress, thus allowing us to dissect the contribution of THO to DED. Our results showed that THO is sufficient to disrupt neuroimmune homeostasis of the ocular surface in mice, and thus reproduce many sub-clinical DED findings. THO activated nuclear factor-κB signalling in conjunctival epithelial cells and increased dendritic cell recruitment and maturation, leading to more activated (CD69+ ) and memory (CD62lo CD44hi) CD4+ T-cells in the eye-draining lymph nodes. Ultimately, THO impaired the development of ocular mucosal tolerance to a topical surrogate antigen in a chain of events that included epithelial nuclear factor-κB signalling and activation of transient receptor potential vanilloid 1 as the probable hypertonicity sensor. Also, THO reduced the density of corneal intraepithelial nerves and terminals, and sensitized the ocular surface to hypertonicity. Finally, the adoptive transfer of T-cells from THO mice to naïve recipients under mild desiccating stress favoured DED development, showing that THO is enough to trigger an actual pathogenic T-cell response. Our results altogether demonstrate that THO is a critical initiating factor in DED development.

Assuntos

RESUMO

In different tissues hyperosmolarity induces cell differentiation. Nevertheless an exacerbated hyperosmolar stress alters the normal cellular development. The transient receptor potential vanilloid 1 (TRPV-1) is a non-selective cation channel that is activated by hyperosmolarity and participates in many cellular processes. TPRV-1 is expressed in human placenta at term. Here, we evaluated the expression of TRPV-1 in first trimester extravillous trophoblast cells and its participation in the survival of these cells exposed to hyperosmolar stress. Our results showed that hyperosmolar stress up-regulates the expression of TRPV-1 and induces the apoptosis in Swan 71 cells. In addition, the inhibition of TRPV-1 abrogates the apoptotic events.

Assuntos

RESUMO

The peroxisome proliferator-activated receptors (PPARs) are ligand-dependent transcription factors involved in lipid metabolism and glucose utilization, in cell growth, differentiation and apoptosis, and in the regulation of pro-inflammatory genes expression such as cyclooxygenase-2 (COX-2). PPARγ is the main isoform in the renal inner medulla where it is believed to possess nephroprotective actions. In this kidney zone, COX-2 acts as an osmoprotective gene and its expression is modulated by changes in interstitial osmolarity. In the present work we evaluated whether hyperosmolar-induced COX-2 expression is modulated by PPARγ in renal epithelial cells MDCK subjected to high NaCl medium. The results presented herein show that ligand-activated PPARγ repressed COX-2 expression. But more important, the present findings show that hyperosmolar medium decreased PPARγ protein and increases the PPARγ phosphorylated form, which is inactive. ERK1/2 and p38 activation precedes PPARγ disappearance and induced-COX-2 expression. Therefore, the decrease in PPARγ expression is required for hyperosmotic induction of COX-2. We also found that PGE2, the main product of COX-2 in MDCK cells, induced these changes in PPARγ protein. Our results may alert on the long term use of thiazolidinediones (TZD) since they could affect renal medullary function that depends on COX-2 for cellular protection against osmotic stress.

Assuntos

RESUMO

BACKGROUND: Chronic dry eye disease often requires long-term therapy. Tear film alterations in the setting of dry eye may include reduced tear volume as well as an increase in inflammatory cytokines and osmolarity. Topical cyclosporine ophthalmic emulsion 0.05% (Restasis(®); Allergan Inc, Irvine, CA) is indicated to increase tear production in patients with dry eye and reduced tear production presumed to be due to ocular inflammation. This study was designed to evaluate the efficacy of a second trial of topical cyclosporine in patients with dry eye who were previously considered treatment failures. MATERIALS AND METHODS: This multicenter (three cornea practices) retrospective chart review evaluated clinical outcomes in patients with dry eye who received a second trial of cyclosporine after a prior treatment failure, defined as prior discontinuation of topical cyclosporine after less than 12 weeks. RESULTS: Thirty-five patients, most of whom were female (71.4%) and Caucasian (62.9%), were identified. Prior discontinuation was most commonly due to burning/stinging (60%). The median duration of second treatment was 10 months (range 1 week to 45 months). Physician education was provided in the second trial in 97.1% of cases. At initiation of the second trial of cyclosporine, 10 (28.6%) patients received courses of topical corticosteroids. Physicians reported on a questionnaire that 80% of patients achieved clinical benefit with a second trial of cyclosporine. CONCLUSION: A repeat trial with topical cyclosporine can achieve clinical success. Direct patient education via the physician and staff may be key to success. Proper patient education may overcome adherence issues, particularly with respect to the need for long-term treatment of chronic dry eye. This study has the usual limitations associated with a retrospective chart review, and future prospective studies are warranted.