Vitreous collagen metabolism before and after vitrectomy.
OBJECTIVE
To assess vitreous metabolism by measuring C-propeptide levels of type II procollagen (pCOL-II-C) and hyaluronan levels in the vitreous and in the vitreous fluid after vitrectomy for macular hole.


METHODS
We obtained 1-ml vitreous samples during vitrectomy from 34 patients (34 eyes) with a macular hole (age range 50-77 years, mean 64 years). After vitrectomy, we performed fluid-air exchange in six eyes because of unresolved macular holes and collected 4-ml fluid samples. Gel-filtration high-performance liquid chromatography (HPLC) was used to determine the molecular weight of pCOL-II-C in the samples. The pCOL-II-C level was measured by sandwich enzyme immunoassay and hyaluronan by sandwich binding protein assay.


RESULTS
HPLC showed that pCOL-II-C in the vitreous samples corresponded to purified pCOL-II-C from cartilage. The vitreous pCOL-II-C level (4.7+/-0.3 ng/ml) was similar to reported synovial fluid levels. In six eyes that underwent fluid-air exchange, pCOL-II-C in the fluid samples remained at a level similar to that in the vitreous samples, while hyaluronan levels in the fluid samples were significantly lower than in the vitreous samples.


CONCLUSIONS
The molecular weight and concentrations of pCOL-II-C in the vitreous are similar to those in joint fluid. In patients with a macular hole, type II procollagen may be secreted persistently into the vitreous cavity before and after vitrectomy.
Itakura
Hirotaka
H
Department of Ophthalmology, Gunma University School of Medicine, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8511, Japan.
Kishi
Shoji
S
Kotajima
Nobuo
N
Murakami
Masami
M
D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003094:Collagen / Q000378:metabolism*; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000378:metabolism*; D011347:Procollagen / Q000378:metabolism*; D011446:Prospective Studies; D012167:Retinal Perforations / Q000601:surgery; D014821:Vitrectomy; D014822:Vitreous Body / Q000378:metabolism* / Q000601:surgery
D015415:Biomarkers; D010446:Peptide Fragments; D011347:Procollagen; C093212:procollagen type II carboxy-terminal peptide; D006820:Hyaluronic Acid; D003094:Collagen