Glial cells of the human fovea.

The exact cellular types that form the human fovea remain a subject of debate, and few studies have been conducted on human macula to solve this question. The purpose of this study was to perform immunohistochemistry on fresh human samples to characterize the glial cells that form the human fovea. Immunohistochemistry was performed using antibodies against proteins expressed in astrocytes or in retinal Müller glial cells or both types of cells on six human macula obtained from eyes enucleated for peripheral intraocular tumors and on two postmortem eyes from healthy donors. The posterior poles of the enucleated eyes were cryosectioned and stained with antibodies against the glial proteins GFAP, vimentin, CRALBP, glutamine synthetase, and connexin 43. A population of cells positive for GFAP and negative for glutamine synthetase and CRALBP that express connexin 43 were identified at the roof of the foveal pit. These cells are distinct from the Müller cone cells described by Yamada and Gass, suggesting that another type of foveal glial cells, most likely astrocytes, are present in the human fovea. This study showed that in humans, astrocytic glial cells cover the foveal pit. Their roles in macula homeostasis and mechanisms of macular diseases disease remain to be determined

Les œdèmes maculaires

L’œdème maculaire est une augmentation de volume de la macula, zone centrale de la rétine, responsable de l’acuité visuelle. Des symptômes visuels handicapent la vie de millions de patients atteints d’œdème maculaire secondaire à une maladie chronique et parfois aiguë de la rétine. Les protéines qui neutralisent la voie du facteur de croissance de l’endothélium vasculaire (VEGF) ou les glucocorticoïdes, au prix d’injections intraoculaires répétées pendant des années, limitent les symptômes visuels. Mieux comprendre pourquoi et comment l’œdème se forme et comment les molécules thérapeutiques exercent un effet anti-œdémateux permettra de mieux prévenir la survenue de cette complication rétinienne handicapante et cécitante