Abstract
Purpose :
The exact mechanisms involved in the development of posterior capsule opacification (PCO) are not completely understood, nor is it certain whether they develop the same way in in-vitro tissue models as in in-vivo. In order to study this, we compared the histopathology of PCO development in cultured lens capsules and naturally developed PCO in IOL containing lens capsules.
Methods :
24 human donor eyes were divided in to three groups: cultured lens capsules (30 days; n=6), lens capsules with IOL (n= 12) and intact lenses (n=6). IOL capsules were subdivided in to two groups depending on the size of their doughnut like growths of cells around the IOL (Soemmering’s ring). All samples were fixed, sectioned and stained with H&E, Vimentin, alfa Smooth Muscle Actin (alpha SMA), Picro Sirius Red (for collagen) and PAX6.
Results :
Morphologically, cultured capsules and less developed IOL capsules tended to develop as monolayers or clusters of small cells, while more developed IOL capsules tended to form globular and fiber like cells. Based on the Vimentin and alphaSMA stains, we found that cultured and less developed IOL capsules consist mainly of mesenchymal cells, while more developed IOL capsules, contain lens epithelial cells (LECs), globular cells and lens fiber cells. In these samples, alpha SMA was only expressed in areas where cells were in contact with the IOL. None of the lenses or cultured capsules expressed either collagen I or III in LECs nor lens fiber cells. However, many IOL capsule samples expressed collagen in areas where cells were in contact with the IOL. PAX6 had a similar distribution in more developed IOL capsules and intact lenses, more expression at the equator and less at the anterior pole; while in less developed IOL capsules and cultured capsules, expression was dispersed and unorganized.
Conclusions :
The similarities between cultured capsules and less developed IOL capsules indicate that our in vitro developed PCO is comparable to early in vivo developed PCO. The expression of vimentin and lack of alpha SMA in globular cells seems to indicate that these are lens fiber precursor cells. The distribution of LECs and the formation of fiber cells in more developed IOL capsules are morphologically very similar to intact lenses, and therefore could be considered attempts at lens regenerations.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.