Reassembly of the corneal epithelial adhesion structures following human epikeratoplasty
D. T. Azar, S. J. Spurr-Michaud, A. S. Tisdale, M. B. Moore and I. K. Gipson
Eye Research Institute, Boston, MA 02114.
Ten epikeratoplasty lenticules removed after surgery were obtained for
immunohistochemical and electron microscopic analysis to determine the
pattern of re-formation of corneal epithelial adhesion structures.
Antibodies to laminin and type VII collagen were used to determine the
presence of basement membrane and anchoring fibrils, respectively. Electron
micrographs were used to determine the percentage of basal cell membrane
occupied by hemidesmosomes, the area of basal lamina per 100 microns of
basal cell membrane, and the average maximum depth of penetration of
anchoring fibrils into the stoma. Nine normal corneas served as controls.
Compared with normal corneas (24.5% of basal cell membrane occupied by
hemidesmosomes; 32.0 microns 2 basal lamina per 100 microns of basal cell
membrane), lenticules removed for optical reasons had near-normal
hemidemosomes as early as 10 weeks following surgery (mean, 20.3%). The
area of basement membrane was reduced (16 microns 2 basal lamina per 100
microns of basement cell membrane). During the course of 2 to 3 years,
irregularities and duplications of the basement membrane were noted.
Compared with normal corneas, the two lenticules removed for persistent
defects had a marked reduction of hemidesmosomes and basement membrane
present under epithelium at 3 and 4 weeks (9.6% of basal cell membrane
occupied by hemidesmosomes and 13.6 microns 2 basal lamina per 100 microns
of basal cell membrane, and 5.4% of basal cell membrane occupied by
hemidesmosomes and 7.2 microns 2 basal lamina per 100 microns of basal cell
membrane, respectively.
