Abstract
Purpose :
Corneal transplantation is a highly successful surgical option for the treatment of advanced corneal disease. One of the primary concerns with corneal transplantation is graft rejection. The corneal transplant service at the University of Missouri has hypothesized that smoking is a major risk factor for allograft failure and that it alters the proteome of human corneal cell lines.
Methods :
The University of Missouri's i2b2 database was used to retrospectively identify patients who underwent corneal transplantation and analyze their smoking status. Patient’s records that were incomplete or age below 18 were excluded from this study. Fisher’s exact test was used for statistical analysis. Human corneal epithelium cell lines were grown to confluence in tissue culture flasks and then incubated with either smoke extract or phosphate buffered saline as control for 16 hrs. These cells were homogenized using RIPA lysis buffer and total proteins were isolated by acetone precipitation method then analyzed by mass spectrometry (LC-MS/MS).
Results :
Of 254 patients who underwent corneal trasnplant surgery, 144 patients had complete demographic information and were included in this study. The study population consisted of 46% female and 54% male subjects. The racial distribution was 87% white, 8% African American, and 5% other. Exactly 84 of these patients had undergone penetrating keratoplasty while 60 of these patients had undergone endothelial keratoplasty. Penetrating keratoplasty showed 41% graft complication compared to endothelial keratoplasty at 18% (p < 0.005). Further, patients with smoking history showed significantly increased corneal transplant failure (59%) within the penetrating keratoplasty group (p < 0.005). The total protein isolated from cultured human corneal epithelial control cells was 6.3 ± 0.2 mg and smoke-treated cells was 6.1 ± 0.3 mg/ T75 flask culture. LC-MS/MS analysis showed a combined total number of abundant proteins of 624 (> 99% confidence on protein ID). Among these total proteins, 571 proteins were detected in both control and smoke treated cells, 37 proteins were uniquely detected only in smoke treated cells, and 16 proteins were detected only in the control cells.
Conclusions :
Our study demonstrates that smokers have significantly higher graft failure compared to non-smokers and that human corneal epithelial cells treated with smoke extract demonstrate an altered proteomic profile.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.