a-method-for-lineage-tracing-corneal-cells-using-multi-color

A Method for Lineage Tracing of Corneal Cells Using Multi-color Fluorescent Reporter Mice

Lineage tracing experiments define the origin, fate and behavior of cells in a specific tissue or organism. This technique has been successfully applied ...

Hillel Yaffe Medical Center

Introduction. We present a case of a metallic foreign body embedded in the anterior chamber angle. After standing in close proximity to a construction worker breaking a tile, a 26-year-old woman using soft contact lens for the correction of mild myopia presented to emergency department for evaluation of a foreign body sensation of her right eye. Methods and Results. Diagnosis was confirmed by gonioscopic examination and a noncontrast CT scan of head and orbits. The foreign body was removed by an external approach without utilizing a magnet. The patient's final outcome was favorable. Discussion. The above is a rare clinical situation, which is impossible to detect on slit-lamp examination without a gonioscopic view. Proper imaging and a specific management are mandatory in order to achieve favorable outcome.

Foreign body embedded in anterior chamber angle.

Accumulating evidence supports the dogma that the corneal epithelium is regenerated by stem cells located exclusively in the limbal niche, at the corneal periphery. Accordingly, limbal stem cells (LSCs) give rise to progenitors that proliferate and migrate centripetally to repopulate the corneal epithelium, which has a short turnover. Moreover, LSC loss leads to corneal opacity and blindness, while limbal grafting restores patients' vision. However, contradicting data suggested that the limbus does not participate in corneal homeostasis and that the cornea contains stem cells. As of today, only indirect evidence for limbal cell migration under homeostasis or injury has been demonstrated. Here, we performed lineage tracing experiments using R26R-Confetti mice to follow K14+ limbal/corneal epithelial cells stochastically induced to express one out of four fluorescent genes. In homeostasis, radial limbal stripes of slow migrating cells proceeded toward the corneal center while, infrequently, slow cycling limbal clones resembling quiescent stem cells were observed. Additionally, rare corneal clones that did not migrate centripetally, but survived for over 4 months, were inspected. In contrast to limbal stripes, corneal clusters had minor contribution to tissue replenishment in homeostasis. Corneal cells, however, significantly contributed to mild wound repair while large limbal streaks appeared within a week following severe wounding that coincided with partial loss of corneal transparency. This data suggest that the mouse limbus largely contributes to corneal renewal while corneal progenitor cells have a long turnover and, therefore, may be able to maintain the corneal epithelium for several months.

Lineage tracing of stem and progenitor cells of the murine corneal epithelium.

A 35-year-old male patient, diagnosed with acute angle-closure glaucoma, did not improve despite intensive treatment with antiglaucoma medications. Ultrasound biomicroscopy revealed a ciliochoroidal effusion. Due to his past history of drug abuse, a urine test was analyzed and found to be positive for cannabis. After topical cycloplegia and oral steroid therapy, his symptoms improved substantially. The present case highlights the role of ultrasound biomicroscopy in evaluating patients with acute angle-closure glaucoma and the role of cannabis abuse in the development of ciliochoroidal effusion.

Article	Year
Foreign body embedded in anterior chamber angle. Case reports in ophthalmological medicine\| PubMed ID: 23091762	2012
Lineage tracing of stem and progenitor cells of the murine corneal epithelium. Stem cells (Dayton, Ohio)\| PubMed ID: 25187087	2015
Unilateral angle-closure glaucoma with ciliochoroidal effusion after the consumption of cannabis: a case report. Case reports in ophthalmology\| PubMed ID: 25606036	2014

Beatrice Tiosano

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