Growth factor deposition in anterior subcapsular cataract.
OBJECTIVE
To characterize immunohistochemically the distribution of growth factors and extracellular matrix (ECM) components in an anterior subcapsular cataract (ASC) and to determine the role of growth factors in the development of ASC.


METHODS
Department of Ophthalmology, Wakayama Medical University, Wakayama, Japan.


METHODS
During cataract surgery in 22 patients, anterior capsules with an ASC were obtained. Sections of each specimen were immunostained with a panel of antibodies against ECM components, growth factors, cytoskeletal components, and signal transduction-related molecules.


RESULTS
Collagen types I, V, and VI; fibronectin; fibrillin-1; and latent transforming growth factor beta binding protein-1 (LTBP-1) were localized to the ECM in ASC tissues. Collagen IV was localized to the ECM and the capsule. Lens epithelial cells (LECs) were positive for alpha-smooth muscle actin (alphaSMA). Lens epithelial cells and ECM stained for transforming growth factor beta2 (TGFbeta2) and TGFbeta3 in all samples, but TGFbeta1 latency-associated peptide (TGFbeta1-LAP) were detected in some samples. Fibroblast growth factor-2 (FGF-2) and hepatocyte growth factor-alpha (HGF-alpha) were localized to the ECM. Lens epithelial cells with nuclear staining for Erk-1, the mitogen-activated protein kinase (MAP kinase) cascade-related molecule, and Smad3, 1 of the Smad family members involving TGFbeta signaling, were detected.


CONCLUSIONS
Matrix components (ie, collagen types, fibronectin, fibrillin-1), as well as growth factors such as TGFbeta1-LAP, TGFbeta2, TGFbeta3, FGF-2, and HGF-alpha, were detected in ASC. Fibrillin-1 might serve as a repository for TGFbetas. These growth factors may modulate the phenotypic alteration and behavior of LECs. The MAP kinase cascade and TGFbeta signaling are both activated in LECs in ASC.
Ishida
Iku
I
Department of Ophthalmology, Wakayama Medical University, Wakayama 641-8509, Japan. ikuchan@wakayama-med.ac.jp
Saika
Shizuya
S
Okada
Yuka
Y
Ohnishi
Yoshitaka
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D057866:Anterior Capsule of the Lens / Q000378:metabolism*; D058442:Capsule Opacification / Q000378:metabolism*; D002386:Cataract / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D055815:Young Adult
D016326:Extracellular Matrix Proteins; D036341:Intercellular Signaling Peptides and Proteins