Lens epithelial cell proliferation

Abstract

Cell proliferation in the vertebrate ocular lens is essential for its establishment, development and growth. Lens cell proliferation features very early in its morphogenesis and results in rapid tissue growth, but becomes increasingly restricted, both spatially and temporally, with age. As the lens is established, so are defined growth zones characterised by polarised regions of cell proliferation and subsequent fibre cell differentiation. These growth zones are tightly regulated by growth factors in the surrounding ocular environment. Although lens epithelial cell proliferation persists throughout life, albeit at a markedly reduced rate with increased age, the majority of epithelial cells in the adult lens remain quiescent. If perturbed, as a result of various ocular pathologies, normal lens cell proliferation is deregulated as epithelial cells re-enter the cell cycle; such cellular hyperplasia often compromises lens function and subsequently results in cataract formation. Identifying the key ocular factors, and understanding the underlying mechanisms regulating lens cell proliferation, will further advance our understanding of the aetiology of cataracts that are characterised by aberrant lens cell proliferation.