In a recent, well-designed study in the Archives, Musch et al1 found that endothelial cell loss in the implanted graft following penetrating keratoplasty (PK) was twice as great in older recipients as in younger recipients.1 They suggested that their findings "... may be indicative of a decreased ability of the host's corneal rim endothelium to provide physiologic and/or anatomic support to the donor endothelium after PK in older recipients."
Additional support for their suggestion may be found in a report of three cases of total graft rejection or primary donor failure in which the graft cleared spontaneously 6 to 17 months following surgery.2 In each instance, the recipient endothelium was believed to be normal. It was thought likely that the recipient endothelium repopulated the donor button. Thus, based on the observations of Musch et al1 and other published experimental observations, donor endothelial cell population appears to be determined,
Baum JL. Predictive Factors for Endothelial Cell Loss After Penetrating Keratoplasty. Arch Ophthalmol. 1993;111(9):1168. doi:10.1001/archopht.1993.01090090018007