Intraokularlinse als Medikamententräger

αVβ8 integrin targeting to prevent posterior capsular opacification

Fibrotic posterior capsular opacification (PCO), a major complication of cataract surgery, is driven by transforming growth factor–β (TGF-β). Previously, αV integrins were found to be critical for the onset of TGF-β–mediated PCO in vivo; however, the functional heterodimer was unknown. Here, β8 integrin–conditional knockout (β8ITG-cKO) lens epithelial cells (LCs) attenuated their fibrotic responses, while both β5 and β6 integrin–null LCs underwent fibrotic changes similar to WT at 5 days post cataract surgery (PCS). RNA-Seq revealed that β8ITG-cKO LCs attenuated their upregulation of integrins and their ligands, as well as known targets of TGF-β–induced signaling, at 24 hours PCS. Treatment of β8ITG-cKO eyes with active TGF-β1 at the time of surgery rescued the fibrotic response. Treatment of WT mice with an anti-αVβ8 integrin function blocking antibody at the time of surgery ameliorated both canonical TGF-β signaling and LC fibrotic response PCS, and treatment at 5 days PCS, after surgically induced fibrotic responses were established, largely reversed this fibrotic response. These data suggest that αVβ8 integrin is a major regulator of TGF-β activation by LCs PCS and that therapeutics targeting αVβ8 integrin could be effective for fibrotic PCO prevention and treatment.

Facile multifunctional IOL surface modification via poly(PEGMA-co-GMA) grafting for posterior capsular opacification inhibition

Posterior capsule opacification (PCO) is a significant complication of intraocular lens (IOL) implantation in cataract surgery, in which the adhesion and proliferation of lens epithelial cells (LECs) on the implanted IOL surface play an important role. The surface modification of IOL to prevent LEC adhesion and proliferation is a practical way to reduce the incidence of PCO. In this study, a multifunctional binary copolymer of poly(ethylene glycol) methacrylate (PEGMA) and glycidyl methacrylate (GMA) was synthesized (poly(PEGMA-co-GMA), PPG) and chemically grafted onto the aminolyzed IOL surface, utilizing the coupling reaction of epoxy and amino groups. Doxorubicin (DOX) was subsequently immobilized on the surface coating via the reaction of epoxy and amino groups as well. Taking advantages of the hydrophilicity of the PEG segments in the copolymer coating and the anti-proliferative effects of the DOX, a multifunctional surface coating was easily established by the synthesized copolymer PPG. Such anti-proliferative drug immobilized hydrophilic coating modification may effectively reduce the cell adhesion and proliferation and thus it is hypothesized to have great potential in PCO inhibition. The synthesis of PPG was confirmed by proton nuclear magnetic resonance spectroscopy (¹H-NMR) and Fourier transform infrared spectroscopy (FTIR). The surface coating immobilization was demonstrated by X-ray photoelectron spectroscopy (XPS). The in vitro drug release profiles and the cell behaviors were also investigated to validate the multifunctional coating inhibition effect on cellular adhesion and antiproliferation. Finally, the in vivo ocular implantation was carried out on rabbit eyes to evaluate the effect of the coating modified IOL on the inhibition of postoperative PCO. It followed that such multifunctional coating modification can effectively inhibit the adhesion and proliferation of LECs and significantly reduce the incidence of PCO. All these results reveal that such PPG copolymer modification provides a facile yet effective way to inhibit PCO formation after IOL implantation.

Drug eluting and hydrophilic intraocular lens surface coating was facilely fabricated via poly(PEGMA-co-GMA) grafting. Such a multifunctional coating reduced posterior capsular opacification incidence after implantation effectively.

Development of a drug-eluting intraocular lens to deliver epidermal growth factor receptor inhibitor gefitinib for posterior capsule opacification prophylaxis

PURPOSE

Different molecular targets, such as the epidermal growth factor receptor, have been identified for the prophylaxis of posterior capsule opacification. This led to the proposal of several drugs, yet drug delivery into the capsular bag remains challenging. The intraocular lens as a drug delivery device would provide a convenient method to allow drug release in the location needed. This is to evaluate the effect of a drug-eluting intraocular lens using an epidermal growth factor receptor inhibitor.

METHODS

Hydrophobic and hydrophilic intraocular lenses were coated with gefitinib using the dip coating technique. The cellular response on the modified intraocular lenses was tested in a human lens epithelial cell line (FHL-124) in an anterior segment model. Furthermore, modified intraocular lenses were implanted into human capsular bags ex vivo. Drug release was determined as well as the biocompatibility on human corneal endothelial cells. Unmodified intraocular lenses served as controls. In addition, immunofluorescence staining with fibronectin as a marker for fibrotic response was conducted.

RESULTS

Both coated hydrophilic and hydrophobic intraocular lenses could attenuate the cell growth of FHL-124 cells in the human capsular bag in comparison to the unmodified controls. Furthermore, gefitinib-soaked intraocular lenses showed a constant drug release over the first 10 days. No reduction in cell viability of corneal endothelial cells occurred. A decrease in fibronectin expression under gefitinib treatment could be observed.

CONCLUSION

In vitro epidermal growth factor receptor seems to be a valuable target for the prevention of posterior capsule opacification. The gefitinib-eluting intraocular lens in this study could inhibit cell growth in non-toxic concentrations.

The intraocular lens as a drug delivery device for an epidermal growth factor-Receptor inhibitor for prophylaxis of posterior capsule opacification

PURPOSE

Posterior capsule opacification (PCO) occurs as a common complication after cataract surgery. Erlotinib is an inhibitor of the epidermal growth factor-Receptor and reduces critical cellular events leading to PCO. In this in vitro study, Erlotinib-modified intraocular lenses (IOLs) employed as a drug delivery device have been evaluated for PCO prevention.

METHODS

The IC₅₀ concentration of Erlotinib was determined by using FHL-124 cells. For the human capsular bag model, 40 cadaver eyes underwent sham cataract surgery. Sixteen capsular bags were exposed to the IC₅₀ of Erlotinib. Intraocular lens (IOL) of three different materials was pharmacologically modified and tested in the anterior segment model and implanted into 24 capsular bags. To test for corneal toxicity, pairs of human cornea were exposed to high concentrations of Erlotinib and corneal endothelial cells (CEC) were exposed to the modified IOL. Release kinetics of Erlotinib from the IOL was measured.

RESULTS

IC₅₀ of Erlotinib was determined to be 10 μm. Erlotinib alone (p = 0.002) and when soaked into IOLs (p < 0.001) significantly increased the number of days needed until total cell coverage of the capsular bags in comparison with the control. Modified IOLs mitigated cell growth in the anterior segment model (p < 0.001). No short-term corneal toxicity was observed up to a concentration of 100 μm, and IOLs did not show toxicity on CEC. Erlotinib was released constantly from IOL.

CONCLUSION

Erlotinib might be of clinical relevance in PCO prophylaxis, as its short-term application induces a long-term deceleration of cellular growth. Erlotinib can be introduced into the eye via soaked IOLs.

EGFR inhibitor Gefitinib attenuates posterior capsule opacification in vitro and in the ex vivo human capsular bag model

PURPOSE

Posterior capsule opacification (PCO) occurs as a common complication after cataract surgery. Gefitinib is a selective inhibitor of the epidermal growth factor receptor (EGFR) which represents a potential pharmacological target for PCO prevention. In this in vitro study, we assessed the effect and biocompatibility of Gefitinib in PCO prophylaxis.

METHODS

The effect of Gefitinib on the key pathological features of PCO was assessed in vitro. We determined growth in the human capsular bag model, prepared from sixteen cadaver eyes that underwent sham cataract surgery. Furthermore, two lens epithelial cell lines, HLE-B3 and FHL-124, were used to determine concentration-based effects on cell proliferation. In addition, cell-migration, matrix-contraction, and cell spreading were investigated. To exclude toxic concentrations, Gefitinib was assessed for its biocompatibility on six different human ocular cell types from the anterior and posterior segment of the eye.

RESULTS

Gefitinib significantly increased the time until confluence of the capsular bag compared to controls (p < 0.001)). In both human lens epithelial cell lines (HLE-B3 and FHL-124), proliferation decreased significantly and as equally strong after incubation with Gefitinib (p < 0.001), as did chemotactic migration (p = 0.004), matrix contraction (p = 0.001), and cell-spreading (p = 0.001). At the IC50 concentration, Gefitinib was well tolerated by six different human ocular cell types of the anterior and posterior segment.

CONCLUSION

The specific EGFR inhibitor Gefitinib might become of clinical relevance in PCO prophylaxis as it attenuated cellular growth and other pathological PCO factors in the ex vivo human capsular bag model and in two human lens epithelial cell lines, while showing good biocompatibility in vitro.