Long-spacing collagen in the human corneal stroma.
An electron microscopic observation of a corneal lenticule removed 14 months after epikeratoplasty because of refractive error and an unused lenticule was carried out to determine the presence of long-spacing collagen. In the removed lenticule, long-spacing collagen, which is often described as the product of the keratocytes migrating from the host corneal stroma, was observed near a keratocyte. However, long-spacing collagen was also observed in the unused lenticule. In this specimen, keratocytes had been destroyed by freezing so that the secretion of long-spacing collagen by keratocytes should have been negligible. Thus, it seemed that long-spacing collagen could exist naturally in the corneal lenticule as well as be newly formed by migrating keratocytes. In addition, we examined four corneas from patients ranging from 2 months to 91 years of age with no past history of corneal diseases or disorders. Long-spacing collagen was seen in the corneal stromas of the aged persons, but not in those of the younger. In the corneas of the 78-year- and 91-year-old, a different appearance from the usual long-spacing collagen was also seen in the collagen fibrils which showed a slightly shorter periodicity resembling experimentally formed 100 nm periodic fibrils in mice. Long-spacing collagen is a common component of normal human corneal stroma and its occurrence seems to correlate with the age-related changes of the tissue.
Hirano
K
K
Department of Ophthalmology, Nagoya University School of Medicine, Japan.
Nakamura
M
M
Kobayashi
M
M
Kobayashi
K
K
Hoshino
T
T
Awaya
S
S
D000368:Aged; D000369:Aged, 80 and over; D003094:Collagen / Q000648:ultrastructure*; D003319:Corneal Stroma / Q000648:ultrastructure*; D017391:Epikeratophakia; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D054140:Refractive Surgical Procedures; D012086:Reoperation
D003094:Collagen