Yih-Shiou Hwang

Extended Release of Bevacizumab by Thermosensitive Biodegradable and Biocompatible Hydrogel

The antibody bevacizumab (Avastin) has been used clinically to treat intraocular neovascular diseases based on its antivascular endothelial growth factor (VEGF) character. The anti-VEGF strategy for retinal neovascular diseases is limited by the short half-life of bevacizumab and thus requires frequent injections. This Article reports the sustained release of bevacizumab from a biocompatible material that is composed of a triblock copolymer of poly(2-ethyl-2-oxazoline)-b-poly(ε-caprolactone)-b-poly(2-ethyl-2-oxazoline) (PEOz-PCL-PEOz). The amphiphilic PEOz-PCL-PEOz triblock copolymer was synthesized in three steps. First, the PEOz was polymerized by methyl p-toluenesulfonate and 2-ethyl-2-oxazoline (EOz), and the living end was terminated by potassium hydroxide methanolic solution. Subsequently, the hydroxyl-PEOz was used as a macroinitiator for the ring-opening polymerization of ε-caprolactone using a Tin(II) octoate catalyst to synthesize the telechelic hydroxylated PEOz-PCL. Finally, the PEOz-PCL-PEOz triblock copolymer was obtained using the 1,6-hexamethylene diisocyanateas a coupling reagent. The PEOz-PCL-PEOz was chemically and molecularly characterized by GPC, (1)H NMR, and FTIR, and its aqueous solution (ECE hydrogel) showed a reversible sol (room temperature)-gel (physiological temperature) phase transition, which serves as an easy antibody-packing system with extended release. The biodegradability of ECE hydrogel was assessed by the porosity formation at different periods by scanning electron microscopy. The ECE hydrogel had no in vitro cytotoxicity on the human retinal pigment epithelial cell line by flow cytometry. The histomorphology and electrophysiology of the rabbit neuroretina were preserved after 2 months of intravitreal injection. In conclusion, the ECE hydrogel has a temperature-sensitive sol-gel phase transition and is effective in vitro. Its intraocular biocompatibility demonstrated its great potential to be widely used in biomedical applications for extended drug release.

Visual Acuity, Optical Components, and Macular Abnormalities in Patients with a History of Retinopathy of Prematurity

PURPOSE To examine the optical components and spectral-domain optical coherence tomography (OCT) findings in children with a history of retinopathy of prematurity (ROP) and to identify any associations between the OCT findings and the visual acuities of the patients. DESIGN Prospective, case-controlled study. PARTICIPANTS AND CONTROLS Children who were between 6 and 14 years of age were divided into the following 4 groups: Patients with a history of threshold ROP who had been treated using laser therapy or cryotherapy (group 1), patients with regressed ROP who had not received any treatment (group 2), patients who were born prematurely but who had no history of ROP (group 3), and normal full-term children (group 4). The posterior poles of the eyes of all of the patients seemed to be normal. METHODS Visual acuities, optical components, and macular thicknesses were measured in 4 groups of patients, and comparisons between the groups were made. Macular thicknesses were measured using OCT. MAIN OUTCOME MEASURES Visual acuity (VA), optical components, and OCT findings. RESULTS We enrolled 133 patients in the study. Patients in group 1 had significantly thicker foveas than the other patients, as demonstrated by OCT, and this finding was negatively correlated with gestational age. The incidence of abnormal foveal contours among patients in group 1 was significantly higher than among the rest of the patients. Retention of the inner retinal layers was noted in group 1 patients; however, the structure of the outer retina remained intact. Greater degrees of myopic shift and astigmatism, steeper corneal curvatures, shallower anterior chamber depths, and thicker lenses were noted in previously treated ROP patients. These findings corresponded with poor VA and high refractive errors in group 1 patients. CONCLUSIONS Patients with a history of threshold ROP are more likely to show abnormal foveal development and have a poorer visual prognosis than other patient groups despite a fundus with no macular dragging, disc dragging, or retinal detachment. A steeper corneal curvature, shallower anterior chamber, and greater lens thickness are the main changes in the optical components in these patients.

Comparison of amniotic membrane graft alone or combined with intraoperative mitomycin C to prevent recurrence after excision of recurrent pterygia

Purpose: Without effective adjunctive therapy, the recurrence rate after excision of recurrent pterygia is high. In an effort to determine a way to better reduce the recurrence of pterygia, we compared the efficacy and safety of amniotic membrane graft (AMG) alone and AMG combined with intraoperative mitomycin C after excision of recurrent pterygia. Methods: Patients with recurrent pterygia were randomly assigned to receive excision of pterygia followed by AMG alone or AMG combined with intraoperative 0.025% mitomycin C for 3 minutes (AMG-mitomycin C). Patients who could be followed up for more than 12 months were entered for data analysis. Conjunctival (potential) and corneal (true) recurrence of pterygia and other complications were recorded. Results: The group receiving AMG alone was made up of 48 eyes in 48 patients, and the group receiving AMG-mitomycin C consisted of 47 eyes in 46 patients. No significant difference was found in age distribution, sex distribution, or duration of follow-up between the 2 groups. Regarding the recurrence rates of each group, 6 conjunctival (12.5%) and 6 corneal (12.5%) recurrences developed in the AMG group, and 4 conjunctival (8.5%) and 6 corneal (12.8%) recurrences developed in the AMG-mitomycin C group. No significant difference was found in the conjunctival and corneal recurrence rate between the 2 groups (P = 0.623 and 0.966, respectively; log rank test), and no major complications developed in either group. Conclusions: AMG alone can be considered an effective alternative adjunctive treatment of recurrent pterygia. The addition of intraoperative mitomycin C did not further reduce the recurrence rate.

Serum Levels of Vascular Endothelial Growth Factor and Related Factors After Intravitreous Bevacizumab Injection for Retinopathy of Prematurity

IMPORTANCE Intravitreous injections of bevacizumab (IVB) have been found to be effective for the treatment of retinopathy of prematurity (ROP). However, serum levels of vascular endothelial growth factor (VEGF) have been found to be suppressed for 2 weeks after IVB in patients with ROP. Changes in serum VEGF levels after IVB in patients with ROP may be important because VEGF also plays a role in the neurodevelopment of newborns. OBJECTIVE To investigate the correlation of levels of VEGF and related growth factors with bevacizumab levels in the systemic circulation after IVB in patients with type 1 ROP. DESIGN, SETTING, AND PARTICIPANTS We studied a prospective case series at an institutional referral center from December 1, 2011, through February 28, 2013. We enrolled patients with type 1 ROP who received IVB. We collected blood samples before and for as long as 8 weeks after IVB. The samples were tested for serum levels of bevacizumab and growth factors, including VEGF, VEGF receptor 1 (VEGFR1), VEGFR2, Tie2, erythropoietin, transforming growth factor β1, insulinlike growth factor type 1, angiopoietin 1, angiopoietin 2, angiopoietinlike 3, and angiopoietin 4. The serum concentrations of these factors were measured using enzyme-linked immunosorbent assays. MAIN OUTCOMES AND MEASURES Serum levels of VEGF, bevacizumab, and the other growth factors before and for as long as 8 weeks after IVB. RESULTS We enrolled 8 patients with type 1 ROP. Bevacizumab levels were elevated 1 day after IVB in the 3 patients for whom measurements were available (mean [SD], 1425 [1010 (95% CI, 0-3934)] ng/mL; P = .13) and remained detectable in the serum as long as 8 weeks after IVB (285 ng/mL for the 1 patient with a measurement available). Serum VEGF levels were suppressed for the same period (mean [SD] level at 1 day after IVB, 379 [226 (95% CI, 190-568)] pg/mL for the 3 patients with measurements available; at 8 weeks, 216 pg/mL for the 1 patient with a measurement available). We found a negative correlation between the serum levels of bevacizumab and VEGF in the patients with ROP who received IVB (r = -0.43 [95% CI, -0.67 to -0.10]; P = .01). No changes were identified in the serum levels of any of the other factors after IVB. Bevacizumab may interfere with the actual level of VEGF in the serum, and the total VEGF level in the serum cannot be determined when bevacizumab is present. Wide CIs were noted in the measurement of these factors, probably owing to the small number of patients enrolled in this study. CONCLUSIONS AND RELEVANCE Serum VEGF levels were suppressed for 2 months after IVB in patients with type 1 ROP owing to the leakage of bevacizumab into the systemic circulation.

Long-Term Tolerability and Serum Concentration of Bevacizumab (Avastin) when Injected in Newborn Rabbit Eyes

PURPOSE. To test the long-term effects and systemic exposure level after single or multiple bevacizumab (Avastin) intravitreal injections in newborn rabbit eyes. METHODS. Four groups of newborn New Zealand rabbits received a single intravitreal bevacizumab injection at a concentration of 1.25 mg/0.05 mL at the ages of 2 (group 1), 4 (group 2), 6 (group 3), and 12 (group 5) weeks. The other group of rabbits (group 4) received three consecutive injections of bevacizumab at a concentration of 1.25 mg/0.05 mL at weeks 2, 6, and 10. Eight days after injection, the serum concentration of bevacizumab was determined in groups 1, 2, 3, and 5. Morphologic and functional changes were evaluated 12 months after bevacizumab injection. RESULTS. Twelve months after either single or multiple intravitreal injections of bevacizumab, newborn rabbit eyes showed no significant differences compared with control eyes on examination with funduscopy, histopathology, or electroretinogram. The serum concentrations when the injections were performed at the ages of 2 (19.4 +/- 8.1 microg/mL) and 4 (10.2 +/- 2.3 microg/mL) weeks were significantly higher than the serum level detected when the injection was performed at 12 weeks of age (2.8 +/- 1.2 microg/mL, P = 0.02 and P = 0.024, respectively). CONCLUSIONS. After 1 year, single and three consecutive intravitreal injections of 1.25 mg bevacizumab in newborn rabbit eyes are well tolerated. Systemic exposure is higher when the injection is performed at an early age.

Choroidal Thickness in Patients With a History of Retinopathy of Prematurity

IMPORTANCE The cause of reduced vision in patients with a history of retinopathy of prematurity (ROP) is not yet fully understood. The role of the choroid in ROP remains unknown and existing studies of choroidal thickness in patients with a history of ROP are limited. It might be helpful to understand the association of the choroid with ROP by measuring the choroidal thickness in patients with a history of ROP and correlating these findings with the visual outcome of these patients. OBJECTIVE To examine choroidal thickness by spectral-domain optical coherence tomography in children with a history of ROP and assess the impact of choroidal thickness on visual acuity. DESIGN A prospective cross-sectional analysis from August 2011 to September 2012. SETTING Institutional referral centers. PARTICIPANTS Children aged 6 to 14 years with a history of ROP were classified into the following 2 groups: patients with a history of threshold ROP and treatment with laser or cryotherapy (treated group) and those with regressed ROP who had not received any treatment (nontreated group). All of the patients had a normal-appearing posterior pole. INTERVENTION Examinations of visual acuity, refractive errors, and optical components and measurement of choroidal thickness. MAIN OUTCOMES AND MEASURES Best-corrected visual acuity, optical components, and optical coherence tomography findings. RESULTS In total, 49 patients were enrolled in the study. Patients in the treated group had a significantly thinner choroidal thickness than the patients in the nontreated group after adjusting for age, axial length, and spherical power. Choroidal thickness was found to be positively associated with spherical power and spherical equivalent and negatively associated with axial length and vitreous depth. In addition, a thin choroidal thickness was associated with a worse best-corrected visual acuity. CONCLUSIONS AND RELEVANCE Choroidal thickness is thinner in patients with threshold ROP compared with the patients with spontaneously regressed ROP. A thinner choroid is associated with worse vision in these patients. This study might imply the association of choroid circulation with ROP.

The validity of clinical feature profiles for cytomegaloviral anterior segment infection

BackgroundAnterior segment cytomegalovirus (CMV) infection, which can be presented as anterior uveitis and corneal endotheliitis, has recently been reported in immunocompetent patients. We would like to access the validity of two presumed characteristic clinical profiles: profile 1, non-herpes simplex virus (HSV)/varicella zoster virus (VZV) corticosteroid-recalcitrant inflammatory ocular hypertensive syndrome (IOHS), and profile 2, corneal endotheliitis with specific coin-shaped keratic precipitates (KPs), that could be helpful in identifying CMV anterior segment intraocular infection.MethodsPatients with either profile 1 or profile 2 or both were enrolled consecutively from the uveitis service in Chang Gung Memorial Hospital, Taoyuan, between January 1, 2006 and May 31, 2010. Diagnostic anterior chamber tapping was performed and followed by real-time quantitative polymerase chain reaction (PCR) to detect herpesviridae DNA including HSV I and II, VZV, CMV, and Epstein–Barr virus.ResultsThirty-one eyes of 30 patients (21 males and nine females) were enrolled in this study. CMV DNA PCR was positive in 29 eyes of 28 patients (20 males and eight females). Nineteen of 20 eyes (19 patients) in profile 1 had positive CMV PCR. Ten of 11 eyes (11 patients) in profile 2 had positive CMV PCR. The positive predictive value of profile 1 and profile 2 was 94.7% and 90.9%, respectively. The positive predictive value of combining the two profiles was 93.3%.ConclusionsNon-HSV/ZVZ corticosteroid-recalcitrant IOHS and corneal endotheliitis with specific coin-shaped KPs could be used as the screening tool for CMV anterior segment intraocular infection.

Serum Vascular Endothelial Growth Factor After Bevacizumab Or Ranibizumab Treatment For Retinopathy Of Prematurity.

Purpose: To investigate vascular endothelial growth factor (VEGF) levels in the systemic circulation after intravitreal injections of bevacizumab (IVB) or ranibizumab (IVR) in patients with Type 1 retinopathy of prematurity (ROP). Methods: Patients who had Type 1 ROP and received IVB or IVR were enrolled. Serum samples were collected before and up to 12 weeks after IVB or IVR treatment. The main outcome measurements were serum levels of VEGF up to 12 weeks after anti-VEGF treatment. Results: In total, 10 patients with Type 1 ROP were enrolled in this study. All the eyes had complete resolution of abnormal neovascularization of ROP after IVB or IVR. In the direct comparison of IVB with IVR, serum VEGF was found to be suppressed more in patients with Type 1 ROP who received IVB treatment, compared with those who received IVR treatment (P = 0.01, P = 0.03, and P = 0.03, respectively, 2, 4, and 8 weeks after intravitreal injection). Conclusion: Serum VEGF levels in patients with Type 1 ROP were suppressed for 2 months after treatment with IVB, and VEGF levels were less affected after IVR treatment. Further studies are warranted to investigate the long-term effects of VEGF changes in ROP patients.

Retinopathy of prematurity and maternal age.

Purpose: To determine the risk factors, especially maternal risk factors, associated with the development of retinopathy of prematurity (ROP) in premature babies. Methods: A matched case-control study involving premature patients was undertaken retrospectively. The case group consisted of premature babies with the subsequent development of ROP. The control group consisted of gestational age-matched and sex-matched premature babies that did not develop ROP during the follow-up period. Risk factors involving patient demographics and maternal characteristics were compared between the case and control groups. Results: A total of 144 patients were included in this study (72 patients in the case group and 72 patients in the control group). Among the 66 possible risk factors compared, only birth weight and maternal age were found to be significant risk factors. Birth weight was significantly lower in the case group (1,248.7 ± 257.8 g vs. 1,335.5 ± 297.2 g, P = 0.01), and maternal age was significantly older in the case group compared with that in the control group (31.2 ± 5.1 years vs. 28.2 ± 5.3 years, P < 0.001). The odds ratio of having babies with ROP was 2.9 when the maternal age was >30 years. Conclusion: Older maternal age is a newly identified risk factor for the development of ROP in premature babies.

Endophthalmitis caused by Pseudomonas aeruginosa in Taiwan.

Purpose: To investigate the clinical settings, treatment given, and visual outcomes for eyes with Pseudomonas aeruginosa endophthalmitis in Taiwan. Methods: This is a retrospective, noncomparative, consecutive case series. Medical records were reviewed in 72 eyes of 71 patients with culture-proven P. aeruginosa endophthalmitis between January 1997 and December 2007. Results: The clinical settings included keratitis/scleritis (44.4%), cataract surgery (15.3%), penetrating keratoplasty (13.9%), endogenous source (12.5%), trauma (6.9%), penetrating keratoplasty with cataract surgery (2.8%), trabeculectomy with cataract surgery (1.4%), trabeculectomy (1.4%), and secondary implant (1.4%). Initial visual acuity ranged from counting fingers to no light perception. Final visual acuity was better than 5/200 in 6 of 72 eyes (8.3%), 4/200 to hand motions in 4 eyes (5.6%), and light perception to no light perception in 62 eyes (86.1%). In vitro testing, the susceptibility patterns of organisms isolated were as follows: ceftazidime (100%), cefepime (100%), aztreonam (100%), imipenem (99%), amikacin (94%), and gentamicin (86%). Five of 16 eyes (31.3%) that underwent primary or secondary pars plana vitrectomy with intravitreal antibiotics achieved a final visual acuity of 5/200 or better compared with 1 of 45 eyes (2.2%) treated with 1 or multiple vitreous tap(s) and intravitreal antibiotics (Fishers exact test, P = 0.004). Conclusion: Despite early diagnosis and treatment with intravitreal antibiotics, visual acuity outcomes were generally poor.