Comparative gene expression profiling of human umbilical vein endothelial cells and ocular vascular endothelial cells

BACKGROUND/AIMS

To investigate the difference between human umbilical vein endothelial cells (HUVEC) and human ocular microvascular endothelial cell (MVEC) gene expression, and to determine if these differences could improve the understanding of ocular angiogenic diseases.

METHODS

The gene expression profiles of HUVEC and matched unpassaged human choroidal, retinal and iris endothelial cells were conducted using Affymetrix GeneChip Human Genome U133 Plus 2.0 arrays. Selected differences were confirmed by real time PCR. Functional cell proliferation assays were used to support microarray findings.

RESULTS

HUVEC showed enrichment for probe sets involved in embryological development while ocular MVEC demonstrated enrichment for probe sets for MHC classes I and II, immune responses and cell signal transduction. Comparison of human retinal and choroidal endothelial cells demonstrated significant differences in the expression of probe sets encoding insulin-like growth factor 1 (IGF-1) signalling. Cell proliferation assays demonstrated the stimulatory role of IGF-1 on retinal endothelial cells compared with choroidal endothelial cells.

CONCLUSIONS

Gene expression profiling has demonstrated that HUVEC are probably not a suitable surrogate for the study of ocular angiogenic disorders. There are also significant differences in the gene expression of human retinal and choroidal endothelial cells, which may be important in the mechanism and treatment of choroidal and retinal neovascularisation.

Comparison of choroidal and retinal endothelial cells: characteristics and response to VEGF isoforms and anti-VEGF treatments

Neovascular eye diseases such as wet age-related macular degeneration and proliferative diabetic retinopathy are two of the most common causes of irreversible visual loss. Although mediated by vascular endothelial growth factor (VEGF), the mechanisms of these diseases are not fully understood. Molecular inhibitors of VEGF including pegaptanib, ranibizumab and bevacizumab are used as treatments for these diseases. However, there have been very few direct comparisons between these agents, and as dose and treatment regimes differ their relative efficacies are hard to determine. In vitro comparisons tend to use cells from different sites or species, which show heterogeneity in their responses. The aim of this study was to compare the characteristics of primary cultures of isolated human choroidal endothelial cells (hCEC) and retinal endothelial cells (hREC), and their proliferation responses to stimulation with VEGF 121 and 165, and to compare the anti-proliferative effects of these three drugs. hCEC and hREC were positive for the cell markers VEGFR1, VEGFR2, CD31, CD34 and von Willebrand's factor (vWF), with greater expression of CD34 on the hREC compared to hCEC. Contrary to previous assumptions VEGF isoforms 121 and 165 were found to be equally potent in stimulating endothelial cell proliferation. However, hREC exhibited higher proliferation with either VEGF isoform compared to hCEC. The anti-VEGF treatments ranibizumab and bevacizumab were effective in decreasing proliferation of hCEC induced by the two VEGF isoforms, individually and in combination, with ranibizumab being moderately more effective, particularly in hREC. Pegaptanib was effective in controlling the proliferation of hCEC stimulated by VEGF 165, but was ineffective against the stimulatory effect of VEGF 121. There were found to be significant differences in microvascular endothelial cells from the retina and choroid, both in the expression of cell markers and their behaviour in response to growth factors and currently available anti-VEGF agents, highlighting the importance of targeting treatments to specific intraocular vascular beds and/or diseases.

Interobserver agreement for the detection of optical coherence tomography features of neovascular age-related macular degeneration

PURPOSE

To investigate the interobserver agreement for the detection of optical coherence tomography (OCT) features of disease activity in patients with neovascular age-related macular degeneration (nAMD).

METHODS

This was a cross-sectional agreement study in which grading of OCT line scans from patients with nAMD was conducted by two retinal specialists before the patients received treatment. Scans were graded for the presence of features of nAMD disease activity (intraretinal cysts [IRC], subretinal fluid [SRF], diffuse retinal edema [DRE], retinal pigment epithelial detachment [PED], and subretinal tissue [SRT]).

RESULTS

Although scans from 78 patients were available for analysis, five patients were excluded because of a mean signal strength of <7. Two hundred seventy-eight line scans were analyzed from 73 patients (40 with cross-hair scan sets and 33 with radial line scan sets). Agreement for per line scan analysis was 77% for IRC (kappa = 0.41), 81% for SRF (kappa = 0.62), 91% for macular fluid (kappa = 0.28), 79% for DRE (kappa = 0.10), 90% for PED (kappa = 0.78), and 79% for SRT (kappa = 0.53). Both observers disagreed regarding the presence of macular fluid in one patient (with a cross-hair scan).

CONCLUSIONS

Interpretation of OCT line scans from patients with nAMD is subject to interobserver variability. However, when all line scans acquired are examined for the presence of fluid (IRC or SRF), there is a high level of agreement for the detection of macular fluid on a per patient basis.

The effects of growth factors on the proliferation and in vitro angiogenesis of human macular inner choroidal endothelial cells

AIM

To investigate the effect of VEGF(165), FGF2, IGF-1, PDGF-AA, PDGF-BB and IL-1 beta on the proliferation and angiogenic tube formation of human macular inner choroidal endothelial cells (ICEC).

METHODS

The proliferation of human macular ICECs after exposure to the aforementioned growth factors was determined by using both a WST-1 colorimetric assay and a cell-counting technique. The effect of growth factors on ICEC angiogenesis was assessed by sprout formation using a three-dimensional in vitro Matrigel duplex assay.

RESULTS

Using both the WST-1 assay and a cell-counting technique, VEGF(165) and FGF2 both significantly increased human macular ICEC proliferation. The effect of equimolar concentrations of VEGF(165) and FGF2 was additive. There was no significant effect for IGF-1, PDGF-AA, PDGF-BB or IL-1 beta on proliferation up to a growth factor concentration of 1000 pmol/l. The angiogenesis assay found a significant effect on sprout formation for VEGF(165) and FGF-2. Again, the effect of equimolar concentrations of VEGF(165) and FGF2 was additive. There was no significant effect for IGF-1, PDGF-AA, PDGF-BB or IL-1 beta on sprout formation at 1000 pmol/l.

CONCLUSIONS

Both VEGF(165) and FGF2 significantly increase human macular ICEC proliferation and sprout formation in an angiogenesis assay. When present together, their effect was additive. IGF-1, PDGF-AA, PDGF-BB and IL-1 beta did not have any significant effect on proliferation or sprout formation in vitro. These results suggest that targeting other growth factors such as FGF2, in addition to VEGF, may be beneficial in the treatment of neovascular age-related macular degeneration.

Prevalence of biometry assessment experiences among trainee ophthalmologists in the United Kingdom

PURPOSE

To determine the biometry assessment experiences of senior house officers (SHOs) during basic surgical training (BST).

METHODS

This is a postal survey of SHOs in recognized UK surgical training posts from April 2005 to November 2005. Data collected included SHO proficiency in various types of biometry, practical biometry experience and opinions as to whether performing biometry is still a required skill.

RESULTS

Of 460 SHOs who were sent questionnaires 279 (60.1%) responded. Only 13% of respondents received formal training in biometry while 43% received informal training in biometry from either senior colleagues or nurses. SHOs maintained they were proficient in different types of biometry including contact biometry (49%), non contact biometry (45%), immersion biometry (2.5%) and keratometry (81%). If their current unit, 84% of SHOs did not perform any biometry. Although the majority of SHOs reported familiarity with IOL power prediction formulae, there was no consistency among the SHOs working in the same unit. Despite the lack of exposure to biometry, most (88%) felt that biometry was still a required skill.

CONCLUSION

This study highlights the lack of training and low prevalence of performing biometry among trainee ophthalmologists. As proficiency in biometry is part of BST and the majority of the trainees wished to learn the skill, it is hoped that this issue will be addressed in the new Ophthalmic Specialist Training curriculum.

Successful Treatment of Invasive Cavernous Sinus Aspergillosis with Oral Itraconazole Monotherapy

An 83-year-old woman receiving long-term prednisolone treatment presented with a right optic neuropathy and right third, fourth, fifth, and sixth cranial nerve palsies secondary to sino-orbital aspergillosis with cavernous sinus involvement. Because the patient refused conventional treatment, she was given a two-year course of oral itraconazole 200 mg/day, leading to a complete imaging resolution of the lesion. Three years after completing treatment, there is no clinical or imaging evidence of disease recurrence. Visual and ocular motor function did not recover, but ptosis and proptosis improved. We believe this to be the first documented case of successful treatment of such a lesion with oral itraconazole monotherapy.

Single perioperative triamcinolone injection versus standard postoperative steroid drops after uneventful phacoemulsification surgery

PURPOSE

To evaluate the safety and efficacy of a single perioperative sub-Tenon's injection of triamcinolone following cataract surgery and its effect on the incidence of early pseudophakic cystoid macular edema (CME).

SETTING

Ophthalmology Department, Queen's Medical Centre University Hospital, Nottingham. United Kingdom.

METHODS

This prospective randomized controlled trial included 54 eyes (54 patients) having routine cataract surgery. Twenty-seven eyes received the conventional postoperative care with steroid drops (drops group), whereas the other 27 were given a perioperative sub-Tenon's injection of triamcinolone (injection group); 10 of these received 20 mg, and the remaining 17 eyes had 30 mg triamcinolone. All patients were evaluated preoperatively and at days 1, 8, 30, and 90. The outcome measures evaluated were logMAR best corrected visual acuity (BCVA), anterior chamber flare (Kowa-500 flare meter), intraocular pressure, and slitlamp biomicroscopy. Oral fluorescein angiograms were performed at 30 and 90 days to detect angiographic CME.

RESULTS

The mean logMAR BCVA improved from a baseline of 0.38 +/- 0.38 (SD) and 0.44 +/- 0.26 to 0.02 +/- 0.14 and 0.0 +/- 0.07 at 90 days in the steroid drops and injection groups, respectively. (P = .59). The mean flare increased from a baseline of 8.9 +/- 3.2 photons/ms and 8.3 +/- 3.7 photons/ms in the steroid drops and injection groups, respectively, to a maximum of +/-14.1 photons/ms and 25.8 +/- 7.5 photons/ms at day 8. Mean flare decreased to 15.8 +/- 9.7 photons/ms and 13.8 +/- 10.1 photons/ms at 30 days (P = .48, difference between groups) and 10.4 +/- 3.6 photons/ms and 9.8 +/- 3.1 photons/ms at 90 days, respectively, in the 2 groups. Subanalysis revealed lowest peak flare (17.9 +/- 7.9 photons/ms) at 8 days in the group that received 30 mg triamcinolone.

CONCLUSIONS

A single sub-Tenon's injection of 30 mg triamcinolone seem to be safe and effective as a route of steroid delivery after uneventful phacoemulsification surgery. Larger numbers in patients at high risk are required to assess its effectiveness in reducing the risk for pseudophakic CME.

Isolation, culture, and characterisation of human macular inner choroidal microvascular endothelial cells

AIM

To develop a method for the reliable isolation of adult human macular inner choroidal endothelial cells (ICECs) and to subsequently characterise them for their expression of a range of endothelial cell associated surface markers.

METHOD

Human ICECs were isolated after manual dissection of maculas from fresh human posterior segments. Following enzyme digestion to form a single cell suspension, the ICECs were isolated using anti-CD31 coated Dynabeads. The isolated cells were grown in culture and examined for typical endothelial cell morphology, surface expression of vWf, CD 31, CD 105, VEGF receptors 1 and 2, and expression of E-selectin after stimulation with TNF-alpha. The cells were also examined for their ability to form fenestrations and capillary-like tubes in Matrigel.

RESULTS

The method enabled the rapid isolation of viable cells that demonstrated typical endothelial cobblestone morphology in culture. The cells stained positive for CD31, vWf, CD105, VEGF receptors 1 and 2, and E-selectin (after stimulation with TNF-alpha). The cells stained negative for alpha smooth muscle actin and fibroblast surface protein. The cells also developed fenestrations when cultured on fibronectin coated plates and formed capillary-like tubes structures when cultured on Matrigel.

CONCLUSIONS

This technique isolates cells from the human macular inner choroid that display features consistent with vascular endothelial cells. These cells could subsequently be used to further the understanding of the pathophysiological mechanisms of diseases of the inner choroid, such as choroidal neovascularisation.

Effect of diabetes mellitus and hyperglycemia on the proliferation of human Tenon's capsule fibroblasts: implications for wound healing after glaucoma drainage surgery

Glaucoma drainage surgery in diabetic patients is associated with a relatively poor prognosis due to increased scarring at the site of surgery, secondary to increased proliferation of human Tenon's capsule fibroblasts (hTCF). This is in marked contrast to diabetic wound healing at other sites, where it is generally impaired. The aim of this study was to determine why diabetics show an increased ocular scarring response in comparison to that found at other sites. Under normoglycemic conditions, hTCF isolated from diabetics showed a mean reduction in short-term proliferation (95% CI) of 45 +/- 12% compared with normal controls (p < 0.001). Under hyperglycemic conditions, proliferation of diabetic hTCF was reduced by 21 +/- 11% (p < 0.01) compared with nondiabetic controls. When exposed to transforming growth factor-beta2 (1-10,000 pg/ml) and platelet-derived growth factor-BB (0.5-500 ng/ml) under both normo- and hyperglycemic conditions, there was a dose-related increase in proliferation of both diabetic and nondiabetic controls. There was no significant difference in response to cytokine stimulation between the two groups at any of the cytokine concentrations used. Western blot analysis did not show any apparent difference in the expression of platelet-derived growth factor receptor alpha, mitogen-activated protein kinase/ERK2, or transforming growth factor-beta receptor II to account for the reduced proliferation of diabetic hTCF. These results suggest that hTCF behave in a manner similar to fibroblasts from other nonocular sites and that the increased proliferation and scarring response found in vivo may be secondary to the previously noted elevated cytokine concentrations in the aqueous and vitreous of diabetics.

A randomised, double-blind trial of topical ketorolac vs artificial tears for the treatment of episcleritis

PURPOSE

To determine whether topical ketorolac (Acular) is more effective than artificial tears in treating the signs and symptoms of idiopathic episcleritis.

METHODS

In this prospective, randomised, double-blind study, 38 eyes of 37 patients presenting with idiopathic episcleritis were allocated to receive either topical ketorolac (0.5%) or artificial tears three times a day for 3 weeks. The severity of patients' signs (episcleral injection and the number of clock hours affected) were recorded at weekly intervals. Patients' symptoms (perceived redness and pain scores) were recorded using a daily diary.

RESULTS

There was no significant difference in the ophthalmic signs between the two groups at each assessment, including intensity of episcleral injection and the number of clock hours affected. No significant difference was found in the time to halve the baseline redness intensity scores (4.4 vs 6.1 days, P=0.2) or pain scores (3.6 vs 4.3 days, P=0.55). Significantly more patients on ketorolac reported stinging at the first follow-up visit (P<0.001).

CONCLUSION

Topical ketorolac is not significantly better than artificial tears in treating the signs or symptoms of idiopathic episcleritis.

Verteporfin photodynamic therapy of choroidal neovascularization in angioid streaks: one-year results of a prospective case series

PURPOSE

To report the 12-month results on the use of verteporfin photodynamic therapy (PDT) in the treatment of choroidal neovascularization (CNV) secondary to angioid streaks.

STUDY DESIGN

Five-center prospective case series.

METHODS

Patients with CNV secondary to angioid streaks who were treated with PDT were recruited and followed up at 3-month intervals for 12 months, with the addition of visits at 1.5 and 4.5 months if deemed appropriate by the investigator. Best-corrected visual acuity (BCVA) was measured at each visit after full refraction or with their current distance spectacles using Early Treatment Diabetic Retinopathy Study logarithm of the minimum angle of resolution charts. Stereoscopic fundus fluorescein angiography was used to determine baseline lesion characteristics and location.

RESULTS

Twenty-two patients were recruited (23 eyes, 16 with subfoveal CNV and 7 with juxtafoveal; all classic no occult). Seventeen patients (77%) had angioid streaks secondary to pseudoxanthoma elasticum. In the subfoveal group, median BCVA at baseline was 49 letters (approximate Snellen equivalent, 20/100) and was 46 at 12 months (approximate Snellen equivalent, 20/125). Twelve of 16 eyes (75%) lost fewer than 8 letters, whereas 14 of 16 eyes (88%) lost fewer than 15 letters. The mean CNV greatest linear dimension (GLD) was 2520 microm at baseline. At 12 months, 7 of 16 eyes with subfoveal CNV at baseline were leaking (GLD = 3220 microm; P = 0.62). The mean number of treatments in the first 12 months was 2.9. In the juxtafoveal group, the median BCVA at baseline was 66 letters (approximate Snellen equivalent, 20/50) and was 51 letters at 12 months (approximate Snellen equivalent, 20/100). Two of 7 eyes (29%) gained 8 or more letters at the 12-month examination, whereas 4 of 7 eyes (57%) lost more than 15 letters. The mean CNV GLD at baseline was 1890 microm. At 12 months, 1 of 7 eyes with juxtafoveal CNV at baseline was leaking. Choroidal neovascularization progressed from juxtafoveal to subfoveal location during the follow-up period in 4 of 7 eyes. The mean number of treatments in the first 12 months was 3.4. No side effects were noted in either patient group.

CONCLUSIONS

This small series suggests that treatment of CNV secondary to angioid streaks with verteporfin PDT seems to limit visual loss in most patients through the first 12 months of follow-up, particularly in those with subfoveal lesions at baseline.

Verteporfin photodynamic therapy for the treatment of persistent subfoveal choroidal neovascularization after external beam radiotherapy: one-year results

PURPOSE

To determine the safety and efficacy of verteporfin photodynamic therapy (PDT) for the treatment of persistent choroidal neovascularization (CNV) previously treated with external beam radiotherapy (EBRT).

DESIGN

Retrospective case series.

METHODS

Verteporfin PDT was performed on 14 eyes of 13 patients with symptomatic leakage from CNV previously treated by EBRT. Principal outcome measures were: comparison of visual acuity at 12 months post-PDT with baseline and the recording of any ocular or systemic adverse events.

RESULTS

At baseline, the mean logMAR (+/-SD) VA was 0.81 +/- 0.33, whereas at the 12-month point it was 0.89 +/- 0.43 (P = .326). At the 12-month examination 10 eyes had lost less than 3 lines of VA, and 8 eyes had lost less than 1.5 lines. During this time, there were 2.1 PDT treatment sessions per eye on average (range = 1 to 4). There were no ocular or systemic adverse events recorded.

CONCLUSIONS

This short-term study shows that verteporfin PDT is safe after EBRT and may be of benefit for recalcitrant CNV.

The effect of corneal thickness on intraocular pressure measurement in patients with corneal pathology

BACKGROUND/AIM

To compare intraocular pressure (IOP) measurements taken by the Goldmann applanation tonometer, the Tono-Pen and the ocular blood flow pneumotonometer in eyes with varying central corneal thickness (CCT) due to penetrating keratoplasty (PK), keratoconus (KC), and Fuchs' endothelial dystrophy (FED).

METHODS

IOP was measured with the Goldmann applanation tonometer, Tono-Pen XL, and OBF pneumotonometer in 127 eyes with the following corneal abnormalities. There were 56 eyes that had undergone PK, 37 eyes with KC, and 34 eyes with FED. CCT was measured using an ultrasound pachymeter after IOP determinations had been made.

RESULTS

Mean IOP measurements in all three patient groups were significantly higher when measured by OBF pneumotonometer. Linear regression analysis showed that patients with FED had a significant increase in IOP with increasing CCT of 0.18 mm Hg/10 microm using the Goldmann tonometer, 0.15 mm Hg/10 microm with the Tono-Pen, and 0.26 mm Hg/10 microm with the OBF pneumotonometer. In patients with KC and after PK, linear regression analysis did not show a significant effect of CCT on IOP. A multivariate linear regression model controlling for age, sex, graft size, and patient group, showed that the effect of CCT on IOP for Tono-Pen (0.13 mm Hg/10 microm CCT) and Goldmann (0.14 mm Hg/10 microm CCT) were significantly lower than for the OBF pneumotonometer (0.26 mm Hg/10 microm CCT).

CONCLUSIONS

This study found that mean IOP measurements using the OBF pneumotonometer were significantly higher than those made using the Goldmann applanation tonometer or Tono-Pen in eyes with a variety of cornel pathologies. The OBF pneumotonometer was found to be most affected by variation in CCT. For all three instruments, the relation between IOP and CCT depended on the corneal pathology and was greatest for FED.