Quantitative evaluation of corneal irregularity and scarring after infectious keratitis using anterior segment optical coherence tomography

PURPOSE

Corneal scars after infectious keratitis lead to insufficient transparency and irregular astigmatism, affecting visual acuity; therefore, they should be accurately evaluated to estimate visual function. This study aimed to quantitatively evaluate corneal irregularity and scarring after infectious keratitis using anterior segment optical coherence tomography (AS-OCT).

METHODS

This was an observational clinical study. We included patients who had corneal scarring after treatment of infectious keratitis between 2014 and 2021 at University of Tokyo Hospital. We retrospectively examined best spectacle-corrected visual acuity (BSCVA), average keratometric power, central corneal thickness (CCT), and four components of the Fourier harmonic analysis including spherical and asymmetry components, as well as regular astigmatism and higher-order irregularity. We included anterior and posterior corneal data and compared results with those of contralateral healthy eyes. Additionally, we quantitatively evaluated the densitometry of the cornea obtained using AS-OCT.

RESULTS

A total of 122 eyes of 61 patients were examined; male predominance was observed (n = 37), and the mean patient age was 55.3 ± 19.4 years. Comparisons with contralateral healthy eyes showed that BSCVA worsened (0.30 ± 0.83 and 0.93 ± 1.36 logMAR, respectively, P = 0.003), and CCT (531.1 ± 46.2 and 591.8 ± 132.4 μm, respectively, P < 0.001) and corneal densitometry (84.4 ± 11.8 and 111.9 ± 19.2 grayscale units, respectively, P < 0.001) increased significantly in affected eyes. The asymmetry component and higher-order irregularities that were not corrected with spectacles significantly increased (both P < 0.001), and there were no significant differences in the changes among the bacterial, fungal, herpetic, and acanthamoeba types of keratitis.

CONCLUSION

Corneal scarring persisted after treatment for infectious keratitis, and the asymmetry and irregularities of corneal astigmatism increased as visual acuity deteriorated. AS-OCT with the Fourier harmonic analysis was useful for evaluating corneal topographic changes in patients with corneal scarring after keratitis.

Epikeratophakia for Keratoconus: A Case Report with 30 Years of Follow-Up

Background

Epikeratophakia is a refractive surgical procedure used to correct aphakic eyes, hyperopia, and keratoconus and is often performed in children. In this report, we present the long-term effects of epikeratophakia on the progression of keratoconus in a patient who underwent surgery. Case Presentation. The patient was a 17-year-old boy with keratoconus who had difficulty wearing hard contact lenses. As a solution, he underwent right eye epikeratophakia with a plano-powered lenticule. We followed up the patient for 30 years. Although the progression of keratoconus ceased in the operated eye, it continued in the nonoperated left eye and resulted in acute hydrops 9 years and 10 months after surgery. Subsequently, 20 years after the operation, anterior-segment optical coherence tomography was performed, which revealed that the progression of keratoconus had been interrupted in the right eye but had continued in the left eye, as evidenced by the parameters of the average and maximum keratometry and thinnest corneal thickness.

Conclusions

Herein, we reported the longest follow-up to date of a case of keratoconus, in which one eye was treated with epikeratophakia. The progression of keratoconus was halted in the treated eye but continued in the nonoperated contralateral eye.

Corneal keloid caused by persistent atopic eye disease and chronic eyelid closure

Purpose

This report aimed to present a case of corneal fibrosis with prolonged atopic blepharitis caused by psychological resistance to steroid treatment.

Observations

A 49-year-old woman presented with atopic dermatitis and a history of panic attack and autism spectrum disorder. The upper and lower eyelid margins of her right eye became adherent, and the eyelid remained closed for several years due to refusal of steroid treatment and aggravation of blepharitis. During the initial examination, a lesion with elevated white opacity on the corneal surface was observed. Subsequently, superficial keratectomy was performed. The histopathological findings were indicative of corneal keloid.

Conclusions and Importance

Persistent atopic ocular surface inflammation and prolonged eyelid closure resulted in the formation of a corneal keloid.

Corneal irregularity and visual function using anterior segment optical coherence tomography in TGFBI corneal dystrophy

The purpose of this study was to evaluate corneal irregular astigmatism of patients with granular and lattice corneal dystrophy (GCD and LCD). 70 GCD, 35 LCD, and 81 control eyes were included. Anterior and posterior corneal topographic data obtained from anterior segment optical coherence tomography were expanded into four components via Fourier harmonic analysis. These components were compared with healthy eyes and the association between each component and best-corrected visual acuity (BCVA) was investigated. Anterior and posterior components increased in both GCD and LCD eyes. Anterior and posterior components of GCD2, anterior of LCD type 1 (LCD1), posterior of LCD type IIIA (LCD 3A), and type IV (LCD4) significantly increased. BCVA was significantly associated with anterior and posterior components in LCD eyes but not in GCD. The anterior components of LCD1, anterior and posterior of LCD3A, and posterior of LCD4 , were positively correlated with BCVA. As conclusions, in GCD eyes, anterior and posterior components differed from those of the control but BCVA was not significantly associated with them. In LCD eyes, the anterior and posterior components increased, and BCVA was significantly associated with the anterior and posterior components.

Impact of rigid gas-permeable contact lens on keratometric indices and corneal thickness of keratoconus eyes examined with anterior segment optical coherence tomography

Purpose/Aim

Detecting keratoconus (KC) progression helps determine the surgical indication for corneal cross-linking (CXL). This retrospective observational study aimed to examine changes in keratometric indices and corneal thickness in patients with KC who used rigid gas-permeable (RGP) contact lenses.

Materials and methods

This study involved 31 eyes (31 patients) diagnosed with KC. No patient had used RGP or any other type of contact lenses for at least 1 month. Corneal topographic data were obtained using three-dimensional anterior segment optical coherence tomography before and after >1 month of RGP lens use.

Results

The average and maximum keratometry values changed after using an RGP lens (-1.05 ± 1.92 D, p < 0.01 and -1.65 ± 4.20 D, p = 0.04, respectively); the spherical component of the anterior corneal surface became significantly smaller (p = 0.02). No change was observed in the central or thinnest corneal thickness values. Keratometric changes were greater in eyes with severe KC than in those with moderate KC (p = 0.014).

Conclusions

Keratometry and spherical components of the anterior corneal surface values decreased after RGP lens use; keratometric changes were greater in eyes with severe KC than in those with moderate KC. Corneal progression indices, including corneal thickness, posterior keratometry, and irregular astigmatism values, mostly remained unchanged. It is important to consider these findings when evaluating corneal topography of KC and preparing CXL.

Spontaneous Corneal Graft Reattachment Following Descemet Stripping Automated Endothelial Keratoplasty in Prone Position: A Case Report and Literature Review

Graft detachment after Descemet stripping automated endothelial keratoplasty (DSAEK) is usually managed with air-bubbling. However, it is an invasive procedure, which can cause corneal endothelial reduction, and requires hospitalization and supine position maintenance. Only few case reports on graft reattachment in the prone position exist, and this is the first report from Japan. An 87-year-old woman presented with sudden pain in her left eye. Examination of her left eye showed a best-corrected vision of 20/50, shallow anterior chamber, cataractous lens, central corneal thickness (CCT) of 630 μm, and corneal endothelial cell count of 467 cells/mm². She was diagnosed with left-eye bullous keratopathy due to primary angle closure, and DSAEK was performed after cataract surgery. Post-surgery, she touched her left eye due to agitation. Graft adhesion was good until postoperative day 4; however, a partial detachment was observed on day 12. She was instructed to remain in a prone position for as long as possible; on day 22, the graft was reattached, and the CCT improved to 555 μm. Since then, the graft adhesion has been maintained, and her best-corrected vision has improved to 20/30. To date, 5 cases of graft reattachment in the prone position have been reported, with reattachment observed in all cases within 10 days from the onset of detachment, including this case. Re-bubbling is an effective technique; however, it is invasive and may cause additional corneal endothelial loss. Therefore, it may be beneficial to have the patient initially attempt the prone position for reattachment.

Three-year results of accelerated transepithelial cross-linking (30 mW/cm2 × 3 min) for keratoconus: a prospective study

Objective

To assess the long-term efficacy and safety of accelerated transepithelial corneal cross-linking (ATE-CXL) with 30 mW/cm2 × 3 min.

Methods and Analysis

Thirty-four eyes of 23 patients with progressive keratoconus (KCN) recruited within a single centre were enrolled in this prospective interventional study. Exclusion criteria included: history of Descemet’s membrane rupture, glaucoma, uveitis, severe dry eye, concurrent corneal infections, and systemic disease that could affect corneal healing. ATE-CXL was performed with 3 min of ultraviolet-A continuous irradiation (30 mW/cm2). Follow-up examinations were scheduled on postoperative day 1; 1 and 2 weeks; 1, 3 and 6 months; and 1, 2 and 3 years. Main outcome measures were maximum corneal power (Kmax), average corneal power (AvgK), steepest corneal power (Ks), central corneal thickness, thinnest corneal thickness, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA) and endothelial cell density.

Results

Mean Kmax, AvgK, Ks, UCVA, BCVA and endothelial cell density did not significantly change over 3 years. The speed of progression obtained by linear regression analysis on corneal parameters (Kmax, AvgK, Ks) improved after ATE-CXL. All baseline parameters correlated with the postoperative Kmax slope. Two eyes underwent ATE-CXL redo because of continued progression after the primary CXL.

Conclusion

This is the first report of 3-year results of ATE-CXL with 30 mW/cm2 × 3 min. ATE-CXL (30 mW/cm2 × 3 min) was safe and effective for slowing down KCN progression.

Trial registration number

This study was registered with ID UMIN000009372 in UMIN-Clinical Trials Registry.

Corneal Graft Rejection after Descemet’s Membrane Endothelial Keratoplasty with Peripheral Anterior Synechiae

Descemet's membrane endothelial keratoplasty (DMEK) for patients with corneal endothelial loss rarely results in graft rejection. Herein, we report a rare case of graft rejection following DMEK, in which peripheral anterior synechiae were observed postoperatively. A 66-year-old woman was referred to our hospital after complaints of decreased visual acuity of her right eye after laser iridotomy for primary angle closure 3 years earlier. Her right cornea had bullous keratopathy with mild cataract, and her best-corrected visual acuity (BCVA) was 20/40. After cataract surgery, DMEK was successfully performed, except for development of peripheral anterior synechiae at the temporal cornea. Her BCVA recovered to 20/20. However, when topical instillation was changed to 0.1% fluorometholone from 0.1% betamethasone once a day, corneal edema reappeared with hyperemia, mutton fat keratic precipitates (KPs), and cells in the anterior chamber. The BCVA worsened to 20/32. Graft rejection was diagnosed, and subconjunctival injection of dexamethasone was performed 3 times, once every few days, with 0.1% topical betamethasone instillation. Subsequently, the hyperemia, mutton fat KPs, and cells in the anterior chamber disappeared with a recovered BCVA of 20/20 after 2 weeks. Ten months after graft rejection, there was no recurrence of intraocular inflammation, and only topical betamethasone was administered twice daily. It is important to exercise caution in cases with peripheral anterior synechiae after DMEK. Long-term steroid administration is necessary to prevent graft rejection.

Comparison of efficacy and safety of accelerated trans-epithelial crosslinking for keratoconus patients with corneas thicker and thinner than 380µm

PURPOSE

Accelerated trans-epithelial cross-linking (ATE-CXL), a therapy to halt keratoconus progression, has the merit of widening the indications for thinner corneas (<380 μm). Since a hypotonic solution affects the swollen cornea, corneas of <380 μm thickness at preoperative measurement can be an indication for ATE-CXL. The aim of this retrospective study was to compare the efficacy and safety of ATE-CXL for keratoconus between corneas with thicknesses <380 μm and ≥380 μm.

MATERIALS AND METHODS

Thirty-four eyes of 27 patients who underwent ATE-CXL (30 mW/cm²; 3 minutes) with completion of a 24-month follow-up, were enrolled and divided into two groups: Group 1, thinnest corneal thickness (TCT), <380 μm (n = 10) and Group 2, TCT, ≥380 μm (n = 24). A hypotonic solution was administered to Group 1 until the corneal thickness increased by >380 μm before UV-A irradiation. We measured uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), maximum and average keratometric values (Kmax and AveK), central corneal thickness (CCT), TCT by anterior segment optical coherence tomography, and corneal endothelial cell density (ECD) using specular microscopy. The changes from baseline to 24 months postoperatively between the two groups were compared accordingly.

RESULTS

The changes in Kmax and AveK from baseline to 24 months in Group 1 (ΔKmax: -7.8±7.7 D, ΔAveK: -4.3±6.1 D) showed significant decreases compared to those in Group 2 (ΔKmax: 0.2±3.0 D, ΔAveK: 0.6±2.7 D) (p = 0.004 and p = 0.001), and there were no significant changes from baseline to 24 months postoperatively in UCVA, BCVA, CCT, TCT, and ECD in both groups.

CONCLUSION

ATE-CXL is effective and safe for keratoconic corneas in both groups. The effect of reducing keratometric values was greater in the group with thinner corneas.

Descemet stripping endothelial keratoplasty after cytomegalovirus corneal endotheliitis and immunosuppression for Mooren's ulcer

Purpose

The aim of this report was to describe a case of cataract surgery and Descemet stripping automated endothelial keratoplasty (DSAEK) after cytomegalovirus (CMV) corneal endotheliitis and bullous keratopathy (BK) following immunosuppressive treatment for Mooren's ulcer.

Observations

A 64-year-old man was referred to our hospital because of peripheral ulcerative keratitis in his left eye. He had a history of trabeculectomy for open angle glaucoma in his left eye. He was diagnosed with Mooren's ulcer and treated with topical betamethasone and tacrolimus with systemic cyclosporine. The corneal ulcer improved, but the peripheral cornea thinned from 6 to 12 and 0-2 o'clock. Five months later, cells were observed in the left anterior chamber, and real-time polymerase chain reaction examination of the aqueous humor showed CMV-DNA-positive results. The patient was diagnosed with CMV corneal endotheliitis, and oral ganciclovir was administered. Fifteen months after the initial presentation, BK appeared with decreased vision to 20 cm/n. d. After confirmation of negative CMV-DNA in the aqueous humor, DSAEK was performed following cataract surgery. The postoperative visual acuity recovered to 0.3. Mooren's ulcer exacerbation and CMV corneal endotheliitis did not recur postoperatively.

Conclusions and Importance

This is the first report of a case in which a patient with Mooren's ulcer developed BK due to CMV corneal endotheliitis and required DSAEK. Cataract surgery and DSAEK could be performed without issue by creating the main wound and side ports in a manner that avoids the thinned parts of the cornea.

Iridotrabecular and Iridocorneal Contact Changes after Cataract Surgery and Endothelial Keratoplasty in Bilateral Iridoschisis

We report a case of bilateral iridoschisis with corneal oedema and a quantitative evaluation of the changes in iridotrabecular and iridocorneal contact before and after cataract surgery and after Descemet stripping automated endothelial keratoplasty (DSAEK). A 76-year-old woman with iridoschisis and cataracts, previously managed with laser iridotomy, experienced progressive vision loss. The preoperative iridotrabecular contact (ITC) index measured by anterior segment optical coherence tomography was 23.6% in the right eye and 24.4% in the left eye. Preoperative corneal oedema in the right eye was more severe than that in the left eye. Cataract surgery, followed by DSAEK, was performed in the right eye and subsequently in the left eye. Her visual acuity improved postoperatively, and the corneal oedema of both eyes was treated successfully. Moreover, the ITC index improved in both eyes, to 4.7 and 6.9% after cataract surgery and to 0 and 0% after DSAEK in the right and left eyes, respectively. Staged cataract surgery and DSAEK were effective for endothelial decompensation caused by iridoschisis. Additionally, we confirm that iridotrabecular and iridocorneal contacts improved after both surgical procedures not only after cataract surgery but also after DSAEK. This case report showed the clinical usefulness of the ITC index in the detection of changes after different surgical procedures.

Risk factors and evaluation of keratoconus progression after penetrating keratoplasty with anterior segment optical coherence tomography

To determine the risk factors and unique characteristics of keratoconus (KC) progression after penetrating keratoplasty (PK), anterior segment optical coherence tomography parameters were statistically analyzed in comparison with eyes undergoing PK for other diseases as a control. Ninety-one eyes maintaining clear PK grafts for over 10 years were divided into 2 groups according to the primary indication for PK (KC vs Others groups). Corneal thinning indicators (inferior host thinnest corneal thickness/central corneal thickness [IHT/CCT], inferior graft thinnest corneal thickness/CCT [IGT/CCT]), were smaller whereas anterior chamber depth, and steepest corneal power (Ks), and maximum corneal power (K_max) were larger in the KC group with statistical significance. Graft size, K_max and Ks correlated with IHT/CCT and IGT/CCT in the KC group. These correlations were not detected in controls. Graft size and postoperative period were selected by multivariate regression analysis as factors for corneal ectatic changes in the KC group. In conclusion, KC eyes long after PK show inferior graft and host corneal thinning, and corneal protrusion. Corneal power parameters such as K_max or Ks can be used to monitor KC progression after PK. A small graft might lead to KC progression after PK.

Loss of Down Syndrome Critical Region-1 Mediated-Hypercholesterolemia Accelerates Corneal Opacity Via Pathological Neovessel Formation

OBJECTIVE

The calcineurin-NFAT (nuclear factor for activated T cells)-DSCR (Down syndrome critical region)-1 pathway plays a crucial role as the downstream effector of VEGF (vascular endothelial growth factor)-mediated tumor angiogenesis in endothelial cells. A role for DSCR-1 in different organ microenvironment such as the cornea and its role in ocular diseases is not well understood. Corneal changes can be indicators of various disease states and are easily detected through ocular examinations. Approach and Results: The presentation of a corneal arcus or a corneal opacity due to lipid deposition in the cornea often indicates hyperlipidemia and in most cases, hypercholesterolemia. Although the loss of Apo (apolipoprotein) E has been well characterized and is known to lead to elevated serum cholesterol levels, there are few corneal changes observed in ApoE^-/- mice. In this study, we show that the combined loss of ApoE and DSCR-1 leads to a dramatic increase in serum cholesterol levels and severe corneal opacity with complete penetrance. The cornea is normally maintained in an avascular state; however, loss of Dscr-1 is sufficient to induce hyper-inflammatory and -oxidative condition, increased corneal neovascularization, and lymphangiogenesis. Furthermore, immunohistological analysis and genome-wide screening revealed that loss of Dscr-1 in mice triggers increased immune cell infiltration and upregulation of SDF (stromal derived factor)-1 and its receptor, CXCR4 (C-X-C motif chemokine ligand receptor-4), potentiating this signaling axis in the cornea, thereby contributing to pathological corneal angiogenesis and opacity.

CONCLUSIONS

This study is the first demonstration of the critical role for the endogenous inhibitor of calcineurin, DSCR-1, and pathological corneal angiogenesis in hypercholesterolemia induced corneal opacity.

Activation of the Sphingosine 1 Phosphate-Rho Pathway in Pterygium and in Ultraviolet-Irradiated Normal Conjunctiva

Sphingosine 1 phosphate (S1P) is a bioactive lipid that regulates cellular activity, including proliferation, cytoskeletal organization, migration, and fibrosis. In this study, the potential relevance of S1P–Rho signaling in pterygium formation and the effects of ultraviolet (UV) irradiation on activation of the S1P/S1P receptor axis and fibrotic responses were investigated in vitro. Expressions of the S1P2, S1P4, and S1P5 receptors were significantly higher in pterygium tissue than in normal conjunctiva, and the concentration of S1P was significantly elevated in the lysate of normal conjunctival fibroblast cell (NCFC) irradiated with UV (UV-NCFCs). RhoA activity was significantly upregulated in pterygium fibroblast cells (PFCs) and UV-NCFCs, and myosin phosphatase–Rho interacting protein (MRIP) was upregulated, and myosin phosphatase target subunit 1 (MYPT1) was downregulated in PFCs. Fibrogenic changes were significantly upregulated in both PFCs and UV-NCFCs compared to NCFCs. We found that the activation of the S1P receptor–Rho cascade was observed in pterygium tissue. Additionally, in vitro examination showed S1P–rho activation and fibrogenic changes in PFCs and UV-NCFCs. S1P elevation and the resulting upregulation of the downstream Rho signaling pathway may be important in pterygium formation; this pathway offers a potential therapeutic target for suppressing pterygium generation.

Poor penetration of cefcapene into aqueous humor after oral administration of cefcapene pivoxil to patients undergoing cataract surgery

OBJECTIVES

Studies on the penetration of orally administered cephalosporins to the aqueous humor are scarce. Therefore, in this study, we determined the concentration of cefcapene, a third-generation cephalosporin administrated orally as pivalate ester (cefcapene pivoxil), in the aqueous humor of patients undergoing cataract surgery to assess its potential for preventing postoperative endophthalmitis.

METHODS

Forty-four patients were administered a single dose of 100 mg cefcapene pivoxil preoperatively. Blood and aqueous humor samples were obtained at the time of surgery, and cefcapene concentrations were measured using ultra-performance liquid chromatography with tandem mass spectrometric detection.

RESULTS

The samples were obtained from 41 eyes of 39 patients (two patients underwent surgery in both eyes). The median cefcapene concentrations in the aqueous humor after 1-2 h, 2-3 h, and later than 3 h were 8.3, 18.4, and 23.7 ng/mL, respectively. The median cefcapene concentrations in serum after 1-2 h, 2-3 h, and later than 3 h were 198.5, 287.2, and 170.3 ng/mL, respectively. Aqueous humor penetration of cefcapene after 1-2 h, 2-3 h, and later than 3 h was 4.1, 7.9, and 13.5% respectively.

CONCLUSIONS

Aqueous humor penetration of orally-administered cefcapene pivoxil in patients undergoing cataract surgery was poor. Therefore, cefcapene pivoxil was unlikely to be effective for preventing endophthalmitis after cataract surgery.

Severity Assessment of Acute Hydrops Due to Recurrent Keratoconus after Penetrating Keratoplasty Using Anterior Segment Optical Coherence Tomography

Purpose: To compare the clinical characteristics of acute hydrops between eyes with recurrent keratoconus and eyes with treatment-naïve keratoconus.Methods: Six eyes with acute hydrops caused by recurrent keratoconus (recurrent group) and 29 eyes with acute hydrops due to treatment-naïve keratoconus (naïve group) were included. We collected data from anterior-segment optical coherence tomography (AS-OCT), corneal topography and medical records. With AS-OCT, we investigated the location of Descemet's membrane break, the length and frequency of Descemet's membrane detachment, and the speed of corneal thinning before acute hydrops.Results: Descemet's membrane breaks were detectable in 6 cases in the recurrent group (100%) and 7 cases in the naïve group (70%). Distance from the break to the central line was 2-3 mm in the recurrent group, and less than 1 mm in the naïve group (p < .001). Detachment length was significantly greater in the recurrent group than in the naïve group (p = .003). Steep corneal power values tended to increase before acute hydrops in the recurrent group, but the difference between groups was not significant (observation period; 6.03 ± 2.67, 7.36 ± 5.53 years, respectively). Penetrating keratoplasty was required in 5 cases (83%) in the recurrent group, and 8 cases (28%) in the naïve group (p = .02).Conclusions: Acute hydrops due to recurrent keratoconus occurred around graft-host junctions and was more severe than that in eyes with treatment-naïve keratoconus. Severity assessment of Descemet's membrane detachment using AS-OCT provided clues not only for diagnosis, but also for predicting prognosis.

Characteristics and risk factors of recurrent keratoconus over the long term after penetrating keratoplasty

PURPOSE

To determine the characteristics and risk factors of recurrent keratoconus (KC) after penetrating keratoplasty (PK).

METHODS

We enrolled patients who had maintained clear grafts for at least 10 years after PK based on their medical records. Patients were divided into the KC group or Others group based on the primary indication for PK. Each case was reviewed for clinically observed corneal ectasia. Steepest keratometric power (Ks), cylinder (CYL), and difference between Ks and minimum keratometric power (MinK) were analyzed in patients that underwent corneal topography more than three times after the 5th postoperative year.

RESULTS

One hundred one eyes of 82 patients were enrolled. The KC group comprised 50 eyes and the Others group comprised 51 eyes (herpes [n = 22], corneal leukoma [n = 12], and other [n = 17]). The mean period after PK was 27.2 years in the KC group and 26.0 years in the Others group. Recurrent KCs were observed in 18 eyes of 14 patients (36%), all of whom were in the KC group (p = 0.0001). Six of these eyes underwent PK again and all the grafts showed keratoconic changes histopathologically. The mean Ks during the whole observation period was 52.5 diopters (D) in the KC group and 49.2 D in the Others group (p < 0.0001). Logistic regression analysis revealed the risk factors of recurrent KC with positive Ks change and large CYL with significant p values (p = 0.0102, 0.0318, respectively).

CONCLUSIONS

KC progresses even after PK over the long term, requiring re-grafting in some cases. Risk factors for recurrent KC after PK are increasing Ks over time and a large CYL.

Screening and Characterization of Drugs That Protect Corneal Endothelial Cells Against Unfolded Protein Response and Oxidative Stress

Purpose

To screen for and characterize compounds that protect corneal endothelial cells against unfolded protein response (UPR) and oxidative stress.

Methods

Bovine corneal endothelial cells (BCECs) were treated for 48 hours with 640 compounds from a Food and Drug Administration (FDA)-approved drug library and then challenged with thapsigargin or H₂O₂ to induce UPR or oxidative stress, respectively. Cell viability was measured using the CellTiter-Glo survival assay. Selected “hits” were subjected to further dose-response testing, and their ability to modulate expression of UPR and oxidative stress markers was assessed by RT-PCR, Western blot, and measurement of protein carbonyl and 8-hydroxydeoxyguanosine (8-OHdG) adducts in immortalized human corneal endothelial cells (iHCECs).

Results

Forty-one drugs at 20 μM and 55 drugs at 100 μM increased survival of H₂O₂-challenged cells, and 8 drugs at 20 μM and 2 drugs at 100 μM increased survival of thapsigargin-challenged cells, compared with untreated control cells. Nicergoline, ergothioneine, nimesulide, oxotremorine, and mefenamic acid increased survival of both H₂O₂- and thapsigargin-challenged cells. Oxotremorine altered DNA damage inducible 3 (CHOP) gene expression, glucose-regulated protein 78 kDa (GRP78) and activating transcription factor 4 (ATF4) protein expression, and protein carbonyl and 8-OHdG levels. Mefenamic acid altered GRP78 protein expression and protein carbonyl and 8-OHdG levels.

Conclusions

Oxotremorine and mefenamic acid are potential survival factors for corneal endothelial cells under UPR and oxidative stress. The described assay can be further expanded to screen additional drugs for potential therapeutic effect in corneal endothelial diseases such as Fuchs' endothelial corneal dystrophy.

Accelerated transepithelial corneal cross-linking for progressive keratoconus: a prospective study of 12 months

BACKGROUND/AIMS

To evaluate the clinical results of accelerated transepithelial corneal cross-linking (CXL) in Japanese patients with progressive keratoconus (KCN).

METHODS

Thirty eyes of 19 patients (16 male, 3 female patients) with progressive KCN were included. The mean age was 24.9±7.0 (range 16-38) years. All patients received ultraviolet A radiation for 3 min at an irradiance of 30 mW/cm². Patients were followed up on the first day, at 1 week and 2 weeks, and at 1 month, 3 months, 6 months and 12 months postoperatively. Clinical examinations included measures of uncorrected visual acuity, best corrected visual acuity (BCVA), average keratometry (AveK), maximum keratometry (Kmax), central corneal thickness, thinnest corneal thickness (TCT), endothelial cell density, intraocular pressure and non-mydriatic indirect fundus examination. Patients were asked to report any pain or discomfort at each visit.

RESULTS

There were no intraoperative or postoperative complications. All 30 eyes finished the follow-up. After 12 months, there was a significant decrease in Kmax (p<0.0001), AveK (p=0.003) and TCT (p=0.002), and a significant improvement in BCVA (p=0.001). There were no other significant changes. Pain or foreign-body sensation following CXL appeared in the first 2 days, but lasted no more than 1 week in all cases.

CONCLUSIONS

There were no complications associated with accelerated transepithelial corneal CXL, and the clinical outcomes were appraisable in a 12-month follow-up.

TRIAL REGISTRATION NUMBER

UMIN000009372.

Characterization of Dental Epithelial Progenitor Cells Derived from Cervical-loop Epithelium in a Rat Lower Incisor

Dental epithelial progenitor cells differentiate into various cell types during development of tooth germs. To study this mechanism, we produced immortalized dental epithelial progenitor cells derived from the cervical-loop epithelium of a rat lower incisor. The expression patterns of cytokeratin 14, nerve growth factor receptor p75, amelogenin, Notch2, and alkaline phosphatase were examined by immnohistochemistry in both lower and higher cell densities. The patterns of each were compared in the dental epithelium of rat lower incisors. The results demonstrated that these cells could produce ameloblast lineage cells, stratum intermedium cells, stellate reticulum, and outer enamel epithelium. Furthermore, fibroblast growth factor 10 stimulated proliferation of dental progenitor cells and subsequently increased the number of cells expressing alkaline phosphatase. These results suggest that fibroblast growth factor 10 plays a role in coupling mitogenesis of the cervical-loop cells and the production of stratum intermedium cells in rat incisors.

Stromal bed quality and endothelial damage after femtosecond laser cuts into the deep corneal stroma

AIM

To evaluate the stromal bed quality and endothelial damage after femtosecond laser (FSL) cuts into the deep corneal stroma.

METHODS

Using a 150-kHz FSL, a lamellar cut was aimed at a depth of 100, 300, or 500 μm in porcine corneas. Stromal bed smoothness was graded from light microscopy and scanning electron microscopy images. Rabbit corneas were cut at remaining thicknesses of 70, 100 and 150 μm using the FSL. The effects of peeling off the corneal flap and the distance between laser spots (2 or 4 μm) were examined.

RESULTS

The ratio of damaged cells in the group with a remaining depth of 70 μm was significantly larger than that in the groups with a remaining depth of 150 μm. The ratio of damaged cells in the group with a 4-μm spot separation and the flap peeled off was significantly larger than that in the group with a 4-μm spot separation and the flap not peeled off.

CONCLUSIONS

Corneal endothelial damage is likely to increase when the remaining depth is less than 70 μm, and peeling off the flap damages corneal endothelial cells when the remaining depth is less than 100 μm.

Angiopoietin-like protein 2 is a potent hemangiogenic and lymphangiogenic factor in corneal inflammation

PURPOSE

We determined the plausible functional role of angiopoietin-like protein 2 (Angptl2) in inflammatory corneal hemangiogenesis and lymphangiogenesis in vivo.

METHODS

Corneal hemangiogenesis and lymphangiogenesis were induced by suturing 10-0 nylon 1 mm away from the limbal vessel in Angptl2 knockout and K14-Angptl2 transgenic mice. We analyzed Angptl2 and interleukin 1β (IL-1β) expressions in normal and vascularized corneas by real-time RT-PCR and immunohistochemistry. Corneal hemangiogenic and lymphangiogenic responses, and macrophage infiltration were assessed by immunofluorescent microscopic studies using specific antibodies against CD31, LYVE-1, and F4/80, and compared to their corresponding background. Subconjunctival injection of Angptl2 siRNA to the sutured corneas was also performed.

RESULTS

Angptl2 mRNA expression increased markedly in the neovascularized corneas compared to the normal cornea. Angptl2 protein was expressed strongly in the corneal epithelium and stroma of the vascularized cornea. The regions showing hemangiogenesis and lymphangiogenesis were increased significantly in K14-Angptl2 mice and reduced in Angptl2(-/-) mice compared to their corresponding background strains. In contrast to control mice, the number of F4/80-positive cells, as well as the expressions of F4/80 and IL-1β were found to be higher in K14-Angptl2 mice and lower in Angptl2(-/-) mice. Subconjunctival injection of Angptl2 siRNA significantly inhibited hemangiogenesis and lymphangiogenesis in the sutured corneas.

CONCLUSIONS

Our findings demonstrated Angptl2 to be upregulated in corneal inflammation, and highlight that corneal hemangiogenesis and lymphangiogenesis may be driven by Angptk2 overexpression via macrophage infiltration and IL-1β expression. Angptl2 may be a novel therapeutic target for preventing blindness.

Activation of muscarinic receptors in rat subfornical organ neurones

Cholinergic muscarinic inputs to subfornical organ (SFO) neurones in rats were studied using histochemical, molecular-biological and electrophysiological techniques. Neurones in the medial septum and the diagonal band (MS-DBB) were retrogradely labelled by a tracer wheat germ agglutinin-conjugated horseradish peroxidase-colloidal gold complex injected into the SFO. Some in the MS-DBB were double-labelled by choline acetyltransferase (ChAT) antibody. Many ChAT-immunoreactive fibres were observed in the SFO. M3 muscarinic receptor subtype-like immunoreactivity, detected using a polyclonal antiserum, was observed in the SFO. In slice preparations, muscarine induced inward currents in a dose-related manner. The inward currents were suppressed by the relatively M3 muscarinic receptor selective antagonist 4-diphenylacetoxy-N-methylpiredine methiodide. In the whole-cell current mode, muscarine depolarized the membrane with increased frequency of action potentials. Reverse transcriptase-polymerase chain reaction showed the presence of M2-M5 receptor mRNA in the SFO tissues. These results suggest that the SFO receives cholinergic muscarinic synaptic inputs from the MS-DBB. Acetylcholine postsynaptically activates and depolarizes neurones in the SFO partly through specific muscarinic receptors, including M3 receptor subtypes.

A novel gene, GliH1, with homology to the Gli zinc finger domain not required for mouse development

The Sonic hedgehog (Shh)-Gli signaling pathway regulates development of many organs, including teeth. We cloned a novel gene encoding a transcription factor that contains a zinc finger domain with highest homology to the Gli family of proteins (61-64% amino acid sequence identity) from incisor pulp. Consistent with this sequence conservation, gel mobility shift assays demonstrated that this new Gli homologous protein, GliH1, could bind previously characterized Gli DNA binding sites. Furthermore, transfection assays in dental pulp cells showed that whereas Gli1 induces a nearly 50-fold increase in activity of a luciferase reporter containing Gli DNA binding sites, coexpression of Gli1 with Gli3 and/or GliH1 results in inhibition of the Gli1-stimulated luciferase activity. In situ hybridization analysis of mouse embryos demonstrated that GliH1 expression is initiated later than the three Gli genes and has a more restricted expression pattern. GliH1 is first detected diffusely in the limb buds at 10.0 days post coitus and later is expressed in the branchial arches, craniofacial interface, ventral part of the tail, whisker follicles and hair, intervertebral discs, teeth, eyes and kidney. LacZ was inserted into the GliH1 allele in embryonic stem cells to produce mice lacking GliH1 function. While this produced indicator mice for GliH1-expression, analysis of mutant mice revealed no discernible phenotype or required function for GliH1. A search of the Celera Genomics and associated databases identified possible gene sequences encoding a zinc finger domain with approximately 90% homology to that of GliH1, indicating there is a family of GliH genes and raising the possibility of overlapping functions during development.

Merkel cells are responsible for the initiation of taste organ morphogenesis in the frog

Taste organs in the frog have a distinctive cell type located exclusively in the basal portion. In the same fashion as type III cells in mammalian taste buds, these basal cells show immunoreactivity for serotonin antibody. Further, these cells are morphologically similar to epidermal Merkel cells. To determine the significance of these serotonergic basal cells, we examined the early development of taste organs during metamorphosis of the frog by focusing on the origin and possible roles of serotonergic basal cells. For convenience of description, five stages of development (metamorphic stage to climax stages A-D) are defined. In the metamorphic stage, a few noninnervated Merkel cells appear at the upper layer of the lingual epithelium. No neuronal elements are seen in the epithelium at this stage. At climax stages A-B, immature fungiform papillae become discernible in the dorsal surface of the tongue, where the Merkel cells are located. Merkel cells then move downward and extend their cytoplasmic processes toward the basal lamina. These cells are identified by their intense immunoreactivity for serotonin. During the later stages, many nerve fibers in the subepithelial connective tissue approach the epithelium containing Merkel cells. At climax stages C-D, Merkel cells extend cytoplasmic processes along the basal lamina toward the center of the newly forming fungiform papillae. The morphology of these Merkel cells exactly coincides with that of serotonergic basal cells in adult taste organs. Profuse exocytotic release of dense-cored granules of Merkel cells toward the nerve fibers through the basal lamina is frequently seen in these stages. The present study indicates that serotonergic basal cells are derived from intraepithelial Merkel cells, which act as target sites for growing nerves and may be responsible for the initiation of taste organ morphogenesis.

Expression of Mash1 in basal cells of rat circumvallate taste buds is dependent upon gustatory innervation

Mash1, a mammalian homologue of the Drosophila achaete-scute proneural gene complex, plays an essential role in differentiation of subsets of peripheral neurons. In this study, using RT-PCR and in situ RT-PCR, we investigated if Mash1 gene expression occurs in rat taste buds. Further, we examined dynamics of Mash1 expression in the process of degeneration and regeneration in denervated rat taste buds. In rat tongue epithelium, Mash1 gene expression is confined to circumvallate, foliate, and fungiform papilla epithelia that include taste buds. In taste buds, Mash1-expressing cells are round cells in the basal compartment. In contrast, the mature taste bud cells do not express the Mash1 gene. Denervation and regeneration experiments show that the expression of Mash1 requires gustatory innervation. We conclude that Mash1 is expressed in cells of the taste bud lineage, and that the expression of Mash1 in rat taste buds is dependent upon gustatory innervation.

Expression of growth/differentiation factor 11, a new member of the BMP/TGFbeta superfamily during mouse embryogenesis

We have cloned and characterized a new member of the bone morphogenetic protein/transforming growth factor beta (BMP/TGFbeta) superfamily, growth differentiation factor 11 (Gdf11), from rat incisor pulp RNA by reverse transcription-polymerase chain reaction using degenerate primers. The mature carboxyl-terminal domain encoded by Gdf11 is most closely related to Gdf8, being 90% identical to the mouse gene. Northern blot analysis revealed Gdf11 is expressed in adult dental pulp and brain. In situ hybridization of sections and whole-mount embryos demonstrated Gdf11 is first strongly expressed in restricted domains at 8.5 days post coitus (dpc) when it is highest in the tail bud. At 10.5 dpc, it is expressed in the branchial arches, limb bud, tail bud and posterior dorsal neural tube. Later, it is expressed in terminally-differentiated odontoblasts, the nasal epithelium, retina and specific regions of the brain.

Transforming growth factor-beta superfamily members expressed in rat incisor pulp

The transforming growth factor (TGF)-beta superfamily comprises more than 35 structurally related genes that have been implicated in embryonic induction and morphogenesis. Different superfamily members may have distinct regulatory roles in tooth development and maintenance. Degenerate primer sets derived from the highly conserved carboxy terminal region of the TGF-beta superfamily were used for reverse transcriptase polymerase with poly(A)+ RNA from the rat incisor pulp as a template. TGF-beta superfamily members expressed in the pulp with known potential to differentiate into odontoblasts and to form dentine were identified. Nucleotide-sequence analysis of the amplified cDNAs identified those encoding activin-betaB; bone morphogenic protein (BMP)-2, -4, -7 and -8; growth/differentiation factor (GDF)-1, -5 and -6; and glial cell line-derived neurotrophic factor. In addition, Northern blot analysis detected TGF-beta1 -beta2 and -beta3; activin-betaA; BMP-6 and GDF-7 mRNA transcripts in the pulp. Coordinated expression of TGF-beta superfamily members in pulp may be critical in tooth development and repair.

Expression of TGF-beta superfamily receptors in dental pulp

Transforming growth factor-beta (TGF-beta) superfamily members and their cell-surface receptors may play inductive and/or regulatory roles in tooth development and repair. It will be important to identify the complete set of TGF-beta superfamily receptors, to examine their temporal and spatial localization during tooth development, and to elucidate the cascade of molecular events of tooth formation induced by the TGF-beta superfamily. In this report, we have cloned the cDNAs encoding potential receptors for TGF-beta superfamily members in rat incisor pulp and bovine adult pulp which are regarded as embryonic and adult pulp, respectively. We analyzed poly (A)+ RNA from rat incisor pulp and bovine adult pulp by reverse-transcriptase/polymerase chain-reaction (RT-PCR), using a degenerate primers corresponding to the most conserved amino acid sequences in the intracellular serine/threonine kinase of type I or type II like kinase-1 (ALK-1), ALK-2, ALK-3 (bone morphogenetic protein receptor type IA, BMPR-IA), ALK-4 (B1), ALK-5, ALK-6 (BMPR-IB), and BMPR-II (BMP type II receptor) was found to be in dental pulp. Northern blot analysis further detected TGF-beta type II receptor (T beta R-II) mRNA transcript in addition to the above-identified receptors. These results provide the first evidence of multiple type I and type II receptors for TGF-beta s, activins, and BMPs expressed in embryonic and adult pulp, implicating diverse function in tooth development and pulp tissue repair.

Temporal changes in expression of transforming growth factor-beta superfamily members and their receptors during bovine preodontoblast differentiation in vitro

Transforming growth factor (TGF)-beta superfamily members and their receptors play a part in the differentiation of pulp cells into odontoblasts during reparative dentinogenesis. Bovine primary pulp-cell culture has been used as an in vitro model for proliferation and differentiation of pulp cells into preodontoblasts. To explore the molecular cascade of odontoblast differentiation, Northern blot analyses and reverse transcriptase polymerase chain reaction were here used to investigate the expression patterns of the genes for TGF-beta superfamily members: TGF-beta 1, namely bone morphogenetic protein (BMP)-4, BMP-7, activin-beta A and activin-beta B, and their type I and type II receptors, namely activin receptor-like kinase (ALK)-2 (ActR-I), ALK-3 (BMPR-IA), ALK-4 (ActR-IB), ALK-5 (T beta R-I), BMPR-II and T beta R-II, during differentiation of pulp cells into preodontoblasts in bovine adult pulp-cell culture. TGF-beta 1 and BMP-4 mRNAs were expressed from day 14 when matrix formation increased. BMP-7 mRNA was expressed only on day 28 when osteocalcin appeared. ALK-2 mRNA was increased from the beginning of the culture. ALK-3 and ALK-5 mRNAs first decreased on day 14 and increased again on day 21. T beta R-II and BMPR-II mRNAs were almost constant. These results suggest that the differentiation of pulp cells into preodontoblasts may be regulated by changes in the temporally coordinated expression pattern of TGF-beta superfamily members and their receptors, including up-regulation of transcription of TGF-beta 1, BMP-4, BMP-7, ALK-2, ALK-3, and ALK-5.