Growth factors and their receptors in the anterior chamber. Absence of epidermal growth factor and transforming growth factor alpha in human aqueous humor.
The involvement of growth factors such as epidermal growth factor (EGF) in regenerative processes of corneal endothelium and lens epithelium has recently been suggested. However, knowledge on the presence of growth factors in anterior chamber fluid (ACF) is still very restricted. Although we have previously shown that EGF is undetectable in the ACF of normal eyes undergoing cataract surgery even by the use of high-sensitivity assays, this does not exclude the possible presence of other, EGF-like proteins in ACF such as transforming growth factor alpha (TGF-alpha). In the present study, we have hence determined in ACF samples of 70 human eyes the concentrations of both EGF and TGF-alpha. As assays served ELISA techniques and RIA. In none of all the samples investigated could detectable amounts of EGF, i.e. above 0.2 pg/ml (detection limit of the assay), be found, confirming earlier results. Interestingly, however, also no TGF-alpha could be detected in ACF. If present at all, the level of any TGF-alpha concentration in ACF was hence below the detection limit, i.e. less than 20 pg/ml. Based on the results of this study, it seems therefore that under physiological conditions there is no measurable presence of free EGF or TGF-alpha in human ACF. Existing receptors in the structures of the anterior segment must hence have ample binding capacity which could explain the effect of externally applied growth factors. The physiological and clinical importance of this result is briefly outlined.
van Setten
G B
GB
St Eriks Eye Clinic, Karolinska Institutet, Stockholm, Sweden.
Fagerholm
P
P
Philipson
B
B
Schultz
G
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000867:Anterior Chamber / Q000378:metabolism*; D001082:Aqueous Humor / Q000378:metabolism*; D002387:Cataract Extraction; D004797:Enzyme-Linked Immunosorbent Assay; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D016211:Transforming Growth Factor alpha / Q000378:metabolism*
D016211:Transforming Growth Factor alpha; D004815:Epidermal Growth Factor; D066246:ErbB Receptors