Effects of Topical Vitamin E on Keratocyte Apoptosis after Traditional Photorefractive Keratectomy

Bi̇lgi̇han, Kamil; Adigüzel, Ufuk; Sezer, Cem; Akyol, Gülen; Hasanreısoğlu, Berati

doi:10.1159/000050857

Cited by 38 publications

(26 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…22 The preventive effect of topical vitamin E on keratocyte apoptosis after PRK has been demonstrated and it is suggested that free radicals might be partly responsible for keratocyte apoptosis after excimer laser keratectomy. 23 …”

Section: Discussionmentioning

confidence: 99%

Keratocyte apoptosis and corneal antioxidant enzyme activities after refractive corneal surgery

Bi̇lgi̇han

Adigüzel

et al. 2002

Eye

View full text Add to dashboard Cite

and corneal antioxidant enzyme activities after refractive corneal surgery AbstractPurpose Refractive corneal surgery induces keratocyte apoptosis and generates reactive oxygen radicals (ROS) in the cornea. The purpose of the present study is to evaluate the correlation between keratocyte apoptosis and corneal antioxidant enzyme activities after different refractive surgical procedures in rabbits. Methods Rabbits were divided into six groups. All groups were compared with the control group (Group 1), after epithelial scraping (Group 2), epithelial scrape and photorefractive keratectomy (PRK) (traditional PRK: Group 3), transepithelial PRK (Group 4), creation of a corneal flap with microkeratome (Group 5) and laserassisted in situ keratomileusis (LASIK, Group 6). Terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nickend labelling assay (to detect DNA fragmentation in situ) and light microscopy were used to detect apoptosis in rabbit eyes. Glutathione peroxidase (Gpx) and superoxide dismutase (SOD) activities of the corneal tissues were measured with spectrophotometric methods. Results Corneal Gpx and SOD activities decreased significantly in all groups when compared with the control group (PϽ0.05) and groups 2, 3 and 6 showed a significantly higher amount of keratocyte apoptosis (PϽ0.05). Not only a negative correlation was observed between corneal SOD activity and keratocyte apoptosis (cc: ؊0.3648) but Gpx activity also showed negative correlation with keratocyte apoptosis (cc: ؊0.3587). Conclusion The present study illustrates the negative correlation between keratocyte apoptosis and corneal antioxidant enzyme activities. This finding suggests that ROS may be partly responsible for keratocyte apoptosis after refractive surgery.

show abstract

Section: Discussionmentioning

confidence: 99%

Keratocyte apoptosis and corneal antioxidant enzyme activities after refractive corneal surgery

Bi̇lgi̇han

Adigüzel

et al. 2002

Eye

View full text Add to dashboard Cite

show abstract

“…The main treatment goal in patients with keratoconus was to increase corneal thickness in preparation for reshaping with refractive surgery and to replace diseased Bowman's membrane and anterior stroma with healthy tissue. In patients with post-LASIK ectasia, the surgical aim was to increase corneal thickness, ablate apoptotic cells in the interface, 18,19 and reduce posterior corneal steepness with tight suturing of the thicker donor lamellae. The goal in the corneal stromal opacity group was to remove diseased stroma and replace it with healthy donor stroma while preserving the host endothelium.…”

Section: Methodsmentioning

confidence: 99%

“…Transepithelial photorefractive keratectomy (PRK) was performed to remove diseased Bowman' s membrane and anterior stroma and to prevent new keratocyte apoptosis. [18][19][20][21] The corneal button and interface were irrigated vigorously with a balanced salt solution. Both the button and interface were dried with fiber-free sponges to remove all debris and maintain the button' s central position by increasing adhesion of the button to the interface.…”

Section: Surgical Techniquementioning

confidence: 99%

Excimer laser-assisted anterior lamellar keratoplasty for keratoconus, corneal problems after laser in situ keratomileusis, and corneal stromal opacities

Bi̇lgi̇han¹,

Özdek²,

Sari³

et al. 2006

Journal of Cataract and Refractive Surgery

Self Cite

View full text Add to dashboard Cite

PURPOSE:To evaluate excimer laser-assisted anterior lamellar keratoplasty to augment thin corneas as in keratoconus (<350 mm) and corneal ectasia after laser in situ keratomileusis (LASIK) and to treat anterior stromal opacities.METHODS: Thirteen eyes (5 keratoconus, 3 macular dystrophies, 1 post-LASIK ectasia, 1 post-LASIK interstitial keratitis, 3 post-herpetic keratitis sequelae) of 13 patients were included in this prospective study. The treatment group was divided into corneal ectasia and stromal opacity groups. A donor stromal button approximately 350 mm thick received a 100 mm excimer laser ablation on the endothelium. The remaining cornea (epithelium, Bowman's membrane, and stroma) was punched with a 7.5 or 7.7 mm trephine. After transepithelial ablation of the host cornea to 200 mm thickness, the corneal button was sutured with interrupted 10-0 monofilament nylon. Sutures were removed between 3 months and 6 months postoperatively. Preoperative and postoperative simulated keratometric cylinders and corneal thickness values were compared using the Wilcoxon signed rank test. The postoperative spherical equivalent refraction and best spectacle-corrected visual acuity (BSCVA) between the groups were compared using the Mann-Whitney U test. RESULTS:The mean follow-up was 27.6 months G 8.3 (SD). All patients gained 2 lines or more of BSCVA, and no patient lost a line. The mean corneal thickness was 381.2 G 88.2 mm preoperatively, which significantly increased to 534.9 G 96.6 mm postoperatively (P<.05). The mean preoperative simulated keratometric cylinder was 7.44 G 7.18 diopters (D); postoperatively, it decreased to 2.61 G 1.73 D (P<.05). There was no significant difference in postoperative spherical equivalent refraction or BSCVA between the groups (P>.05).CONCLUSIONS: This technique presents a different modality for the treatment of keratoconus, post-LASIK corneal problems, and other corneal stromal opacities with anterior lamellar keratoplasty. Additional studies with more patients and longer follow-up will help determine the role of this technique as a substitute for penetrating keratoplasty in these patients. J Cataract Refract Surg 2006; 32:1264-1269 Q 2006 ASCRS and ESCRSPenetrating keratoplasty (PKP) has become the standard surgery for the treatment of most corneal pathologies including keratoconus and corneal opacities. Despite the surgery's popularity, there is a continuous ongoing search for new surgical techniques using recent technological developments to eliminate the well-known problems associated with PKP. 1-17 Anterior lamellar keratoplasty has several advantages over PKP including preservation of the host endothelium, avoidance of complications associated with open-sky surgery, decreased risk for allograft rejection, and superior wound strength. 1-5 Preservation of the host endothelium is vital for long-term graft survival in younger patients. Although treatment of keratoconus with anterior lamellar keratoplasty is well established during end-stage Q 2006 ASCRS and ESCRS Published by Elsevier ...

show abstract

“…Vitamin A is thought to be an essential factor for normal epithelial cell growth, and its deficiency can result in xerosis of the ocular surface and other organs [27,34]. Vitamin A downregulates the number of EGF receptors of the conjunctival epithelium, thus promoting differentiation of conjunctival cells [42], and vitamin E can prevent keratocyte apoptosis [3].…”

Section: The Epitheliotrophic Factors In Serum Eyedropsmentioning

confidence: 99%

An optimised protocol for the production of autologous serum eyedrops

Liu

Hartwig

Harloff

et al. 2005

Graefe's Arch Clin Exp Ophthalmol

137

View full text Add to dashboard Cite

Background: Serum eyedrops have been successfully used in the treatment of severe dry eye, persistent epithelial defects and other severe ocular surface disorders. A number of clinical studies showed a variable efficacy of this approach, but the parameters for the production of this blood product varied significantly. In order to establish an optimised protocol for the production of serum eyedrops, we examined the effect of various clotting times, centrifugation forces, types of diluent and dilutions on the concentration of growth factors, fibronectin, and vitamins in serum and tested the epitheliotrophic capacity of these serum modifications in a cell culture model of human SV-40-immortalised corneal epithelial cells (HCE-T). Methods: Serum samples were prepared with a clotting time of 20, 60 or 120 min, a centrifugation force of 500×g or 3,000×g, and diluted with BSS or isotonic saline. The concentrations of EGF, TGF-β1, PDGF-AB, FGF, HGF, fibronectin, vitamin A and vitamin E in these samples were evaluated with ELISA and HPLC. HCE-T cells were incubated for 24, 48, 72, 96 and 144 h with 100, 50, 25, 12.5, 6.25 and 3.125% serum in diluent, and cell proliferation, migration and differentiation were evaluated by means of a luminescencebased ATP assay, a colony-dispersion assay and scanning electron microscopy. Results: Using a longer clotting time resulted in an increased concentration of all the epitheliotrophic factors examined in serum; the diffference was statistically significant for EGF, TGF-β1 and HGF. Increasing the g force of centrifugation from 500×g to 3,000×g resulted in significantly less TGF-β1, but more EGF and vitamin A. Cell proliferation was better supported by serum prepared with 3,000×g and diluted with BSS. Serum prepared with a longer clotting time yielded better cell migration and differentiation. Conclusion: Clotting time, centrifugation and diluents have a significant impact on the composition and epitheliotrophic effects of serum. A long clotting time (≥120 min), a sharp centrifugation (3,000×g for 15 min) and dilution with BSS improve the ability of serum eyedrops to support proliferation, migration and differentiation of corneal epithelial cells.

show abstract

Effects of Topical Vitamin E on Keratocyte Apoptosis after Traditional Photorefractive Keratectomy

Cited by 38 publications

References 10 publications

Keratocyte apoptosis and corneal antioxidant enzyme activities after refractive corneal surgery

Keratocyte apoptosis and corneal antioxidant enzyme activities after refractive corneal surgery

Excimer laser-assisted anterior lamellar keratoplasty for keratoconus, corneal problems after laser in situ keratomileusis, and corneal stromal opacities

An optimised protocol for the production of autologous serum eyedrops

Contact Info

Product

Resources

About