Elevated TGF-β2 level in aqueous humor of cataract patients with high myopia: Potential risk factor for capsule contraction syndrome

PURPOSE: To evaluate the level of transforming growth factor-β2 (TGF-β2) in the aqueous humor of highly myopic cataract patients and its correlation with capsule contraction syndrome. SETTING: Eye and ENT Hospital of Fudan University, Shanghai, China. DESIGN: Prospective comparative case series. METHODS: The highly myopic cataract patients were divided into the following 2 groups according to the Lens Opacity Classification System III: nuclear color (NC) 2 to 3 and NC 5 to 6. Aqueous humor TGF-β2 concentrations were assayed in the highly myopic cataract and age-related cataract groups. The TGF-β2, TGF-βRII (the type II receptor for TGF-β2), and α-smooth muscle actin (α-SMA) expressions in lens epithelial cells (LECs) were detected by real-time polymerase chain reaction and immunofluorescent staining. RESULTS: The study comprised 40 highly myopic cataract patients (40 eyes) and 20 patients (20 eyes) with age-related cataract as the control group. Compared with the control group, the highly myopic cataract group had significantly higher TGF-β2 concentration in the aqueous humor and increased TGF-βRII expression in LECs, especially in NC 5 to 6 cases. Expression of α-SMA was barely detectable in both groups. CONCLUSION: In highly myopic cataract patients, especially those with dark nuclei, elevated aqueous humor TGF-β2 levels and the upregulated TGF-βRII expression in LECs might contribute to the pathogenesis of capsule contraction syndrome through transdifferentiation of LECs into myofibroblasts. FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.