LSCD strategy

Sophie X Deng MD, PhD

The concept of a one-size-fits-all approach to transplantation for limbal stem cell deficiency (LSCD) is completely out-of-date, and a more individualised strategy that recognises different methods may be warranted depending on the severity of the disease, according to Sophie X Deng MD, PhD.

Progress toward that goal, however, will depend on the development of better techniques for diagnosing and grading LCSD, she told the 2016 annual meeting of the Association for Research in Vision and Ophthalmology in Seattle, USA.

To that end, Dr Deng and colleagues have been investigating the use of in vivo laser scanning confocal microscopy to establish parameters for quantifying stem cell function.

“Quantification of limbal stem cell (LSC) function in vivo could help to classify LCSD severity, monitor its progression, and objectively measure the efficacy of our therapies,” said Dr Deng, Associate Professor, Stein Eye Institute, UCLA, Los Angeles, USA.

CELLULAR LEVEL

Findings from their research support a role for using the diagnostic technique that provides high resolution images at cellular level detail. Dr Deng presented cases considered to have total LSCD that were found with confocal microscopy to harbour “hidden normal limbal epithelial cells”. Their studies have also shown that the morphology of the corneal and limbal epithelium begins to change in eyes with early LCSD, whereas eyes with late-stage disease lack any phenotypically normal corneal or limbal epithelium.

SURPRISING FINDING

In addition, they have found that basal epithelial cell density and epithelial thickness in both the central cornea and limbal region is significantly decreased in eyes with LSCD, and for both parameters, the extent of the decrease correlated with LSCD severity.

As a somewhat surprising finding, corneal sub-basal nerve density was also seen to be significantly decreased in eyes with LSCD. The change was noted even in eyes with early-stage disease, whereas many eyes with late-stage LSCD had no detectable nerve fibres, Dr Deng said.

FUTURE ADVANCES

She also suggested that future advances in LSC transplantation will benefit from better understanding of how trophic factor secretion versus stem cell pool repopulation contribute to epithelium homeostasis and successful ocular surface reconstruction.

“Now is an exciting time to be studying LSC function and to look into what is happening after stem cells are transplanted on to the eye. I think the time has also come to have controlled clinical trials comparing different therapies so that we can investigate their relative efficacy,” Dr Deng said.

Sophie X Deng: deng@jsei.ucla.edu