Neural crest origin of human trabecular meshwork and its implications for the pathogenesis of glaucoma

We used an immunohistochemical method to examine the distribution of neuronal-specific enolase in the trabecular meshwork of adult normal human eyes, as well as in primary cultures of human trabecular cells maintained in vitro for up to 44 days with or without the addition of nerve growth factor. In tissue sections of the globes, neuronal-specific enolase was present in the cells of the anterior region of the meshwork and those of the inner uveal beams. The cells of the posterior region of the meshwork stained variably with antiserum against neuronal-specific enolase. Cultured trabecular cells were initially neuronal-specific enolase-positive, but became negative after 18 to 21 days in vitro. The addition of nerve growth factor restored the expression of neuronal-specific enolase in these cultured cells. Because the presence of neuronal-specific enolase in normal cells is believed to indicate their differentiation from neuroectoderm, our results provide evidence that the trabecular cells in human eyes are derived from the embryonic neural crest. Our finding also supports the hypothesis that abnormal migration or a defective terminal induction of the neural crest cells has a role in certain ocular diseases that are characterized by chamber angle anomalies or primary glaucoma.