Platelet-derived growth factor-BB (PDGF-BB) in tear fluid: a potential modulator of corneal wound healing following photorefractive keratectomy.
OBJECTIVE
To measure the pre- and postoperative tear fluid platelet-derived growth factor-BB (PDGF-BB) concentrations of patients undergoing excimer laser photorefractive keratectomy (PRK).


METHODS
Tear fluid samples from PRK patients were collected with scaled microcapillary tubes preoperatively (Day 0, N = 23), on the second (Day 2, N = 24) and on the seventh (Day 7, N = 14) postoperative days. The PDGF-BB concentration was measured using a sandwich enzyme immunoassay, and the PDGF-BB release was calculated by multiplying the concentration by the tear fluid flow in the collection capillary.


RESULTS
The mean tear fluid flow in the capillary was 17.4 microliters/ min (range 1.4-55.0) on Day 0, 62.6 microliters/min (4.3-125.0, p = 0.0000) on Day 2, and 15.5 microliters/min (1.2-50.0, NS) on Day 7. Seventeen percent (4/23) of the Day 0 samples contained detectable concentrations of PDGF-BB (range 95-1330 ng/l). On Day 2 all (24/24) tear samples showed significantly increased concentrations (mean 507 ng/l, range 45-2280 ng, p = 0.0001) and releases (mean 27.6 pg/min, range 1.0-98.0; p = 0.0000). On Day 7 PDGF-B was still measurable in 9/14 samples (mean concentration 194 ng/l, range < 5-925 ng/l, and mean release 1.9 pg/min, range 0.04-6.8 pg/min).


CONCLUSIONS
PDGF-BB is an inducible component of tear fluid. In spite of hypersecretion caused by the corneal wound, PDGF-BB concentrations raised significantly during the initial wound healing. Increased PDGF-BB release during the two postoperative days following PRK suggests a role in corneal wound healing.
Vesaluoma
M
M
Department of Ophthalmology, Helsinki University Central Hospital, Finland.
Teppo
A M
AM
Grönhagen-Riska
C
C
Tervo
T
T
D000328:Adult; D000925:Anticoagulants / Q000378:metabolism*; D000077214:Becaplermin; D003315:Cornea / Q000503:physiopathology / Q000601:surgery*; D003316:Corneal Diseases / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D018903:Photorefractive Keratectomy; D010982:Platelet-Derived Growth Factor / Q000378:metabolism*; D020574:Proto-Oncogene Proteins c-sis; D013666:Tears / Q000378:metabolism*; D014945:Wound Healing / Q000502:physiology*
D000925:Anticoagulants; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D000077214:Becaplermin