P63 staining on human ocular surface

Purpose: It has been recently hypothesized that transcription factor p63 may be the earlier marker of epithelial stem cells during development. This paper evaluates the p63 location of the corneal and limbal area to find out the p63 expression pattern in the ocular surface. Methods: Human cornea and limbal tissue were used to detect p63 protein expression by immunohistochemistry. In situ hybridization with sense and anti-sense p63 probes were performed on the corneal and limbal tissue to confirm the p63 mRNA express pattern at the cornea and limbus. Results: P63 protein and mRNA were expressed only in the nuclei of the limbal basal epithelial cells layer. There was no staining on the corneal epithelial cells and limbal superficial epithelial cells. Conclusion: According to our findings, p63 which is located in limbal basal epithelial cells is a good marker for corneal stem cells, P63 could be used in the clinic practice to evaluate corneal stem cell activity.Propósito: Recientemente se ha hipotetizado que la proteína nuclear p63 es el primer marcador de las células madres del epitelio corneal durante el desarrollo. La presente publicación determina la localización de las células queratolimbales madres del epitelio corneal por el patrón de expresión p63 en la superficie ocular. Métodos: Se usó tejido queratolimbal humano para detectar por inmunohistoquimia el patrón de expresión de la proteína p63. Se desarrolló la hibridización in situ bidireccional para confirmar la expresión p63 mRNA en el anillo queratolimbal. Resultados: La proteína p63 y ARNm se expresaron sólo en los núcleos de la capa basal de las células epiteliales limbales. Conclusión: De acuerdo con nuestros hallazgos, la proteína p63 localizada en la células basales del epitelio queratolimbal es un buen marcador para detectar las células madres del epitelio corneal. La p63 podría utilizarse en práctica clínica para determinar la actividad de las células madres del epitelio corneal

Transplante limbal alógeno. Su supervivencia determinada por la clínica y la citología de impresión

Objetivos: Investigar el efecto del transplante querato-limbal alógeno (TQLA) para tratar los defectos epiteliales corneales persistentes. Métodos: Se efectuó TQLA en 5 ojos que padecían defectos epiteliales corneales que persistían durante 21,8±11,3 semanas. Se previno el rechace inmunológicos con Ciclosporina A. Cada caso se siguió clínicamente y por citología de impresión antes del TQLA y 1, 3, y 6 meses después de él. Resultados: El defecto epitelial corneal curó en 2,6±0,5 semanas. Todos los casos mostraron un epitelio inestable cuando se suprimió la inmunosupresión. La citología de impresión mostró que las nuevas células epiteliales limbales sobrevivían, pero eran escasas y anormales. Conclusiones: El TQLA es un procedimiento viable para la reconstrucción corneal. La inmunosupresión es obligatoria.Objective: To investigate the effect of allograft kerato-limbal transplantation (AKLT) for treating persistent corneal epithelial defects. Methods: AKLT was performed on 5 eyes with corneal epithelial defects, which have been present for 21.8±11.3 weeks. Immune rejection was prevented with Cyclosporin A. Clinical examination and impression cytology were done prior to and 1, 3 and 6 months after AKLT. Results: The epithelial defects healed in 2.6±0.5 weeks. All cases showed unstable ocular surface when immunosuppression was discontinued. Impression cytology showed survival of the new limbal epithelial cells, but their number was scarce. Conclusions: AKLT is a viable procedure for cornea reconstruction. Immunosuppression is necessary after AKLT

El aminoácido taurina está presente en grandes cantidades en lágrima humana

Purpose: Amino acids in micromolar range are present in free form in most of the extracellular fluid including blood, cerebrospinal fluid, and urine. Moreover, it is well known that they are also present in liquid secretions from exocrine glands such as milk, saliva, and semen with different functional roles. However, as far as we know there is a scarce knowledge about the presence of these compounds on human tears. Our purpose is to assess the presence of free amino acids on the product secretion of the human lacrimal gland, the tear, to better understand the function of these compounds on corneal and conjunctival physiology. Methods: Tear fluid was taken on filter paper without stimulation during a regular Schirmer`s test from the eyes of 36 healthy people which were aged between 18-50 years, and weighted. Filter papers were immediately dropped on tubes containing a sulfosalicylic acid solution (15% w/v, pH below 1) to extract soluble compounds including the amino acids, and to remove the proteins. Samples were maintained for 20 min at room temperature and then stored at -20ºC. Aliquots of these samples were analyzed for amino acid content by reversed-phase HPLC (High Performance Liquid Chromatography) technique using a pre-column fluorescent method with o- phthalaldeyde (OPA) derivatization. Results: We have detected and measured eleven amino acid including: aspartate, glutamate, serine, glutamine, histidine, glycine, threonine, arginine, taurine , alanine and tyrosine. Glutamine, which is the main amino acid in several extracellular fluids is only present in micromolar amounts on tears, in the range of low micromolar (0.06-0.40mM). Surprisingly, however, the tear levels of taurine, an amino acid, not present in proteins; without any metabolic role and seldom exists in extracellular fluid, raises to the millimolar amounts (0.14-5.7mM). The quantities of other amino acids resemble the plasma content. Conclusions: Because of the well known properties of taurine as an antioxidant and a membrane protecting agent, a physiological role in protecting the epithelial cells of the cornea and the conjunctiva has been proposed due to the high amount of taurine found in human tears