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Yamazaki et al. (422) report on the development of senescent features in porcine trabecular meshwork cells in vitro and suggest their involvement in the development of POAG. This simple study supports the current established literature, which state that trabecular meshwork cells exhibit characteristics of senescence following multiple passages in vitro. In addition previous reports have shown that in ageing trabecular meshwork cells there is a shift in the balance of extracellular matrix proteins, which includes fibronectin, proteoglycans and collagen IV in vitro and in vivo. These changes in the amount of collagen to other surrounding matrix components have been suggested to increase the resistance to aqueous humour outflow, and thereby contribute to the currently proposed
Cellular senescence is an important part of the normal ageing processpathophysiology of POAG. This study did not report on the possible functional changes that may be expected to be seen with senescent trabecular cells, in particular with regards to collagen and matrix synthesis and their remodeling, which is an important factor to consider.Cellular senescence is an important part of the normal ageing process, therefore it would be interesting to know whether senescent trabecular meshwork cells contribute in any way to the structural and functional changes seen in the ageing trabecular meshwork.