[Treated cases of retinopathy of prematurity in Germany : 5-year data from the Retina.net ROP registry]

BACKGROUND

Retinopathy of prematurity (ROP) is one of the main reasons for childhood blindness. The number of infants requiring treatment, however, is low for individual centers. The Retina.net ROP registry has been founded to allow a joint analysis of treatment patterns and courses post treatment.

OBJECTIVE

This paper reports treatment patterns over 5 years.

MATERIAL AND METHODS

All infants born between January 2011 and December 2015 who were entered into the treatment registry by one of the 12 participating centers were analyzed.

RESULTS

The data of 150 infants (292 eyes) were analyzed and ROP 3+ in zone II was the most prevalent treatment indication. Gestational age and birth weight remained stable over the years. The treatment patterns, however, changed with anti-VEGF treatment (bevacizumab or ranibizumab) accounting for only 10% of treated eyes in 2011 but for 56% and 30% in 2014 and 2015, respectively. Almost all eyes with AP-ROP or zone I disease received anti-VEGF treatment. Zone II disease was predominantly treated with laser photocoagulation. Recurrences were more common and appeared later in the anti-VEGF group compared to the laser group (23%/interval 60 days vs. 17%/interval 23 days). Perioperative complications were evenly distributed across treatment groups.

CONCLUSION

The data in this analysis represent about 10-15% of treated infants in Germany. The results provide evidence for an increasing use of anti-VEGF agents for ROP. The data reflect a selection bias for anti-VEGF treatment in eyes with a more aggressive disease. This needs to be considered when interpreting data such as disease recurrence rates. The risk for late recurrences after anti-VEGF treatment is of particular clinical significance.

Semaphorin 3F Modulates Corneal Lymphangiogenesis and Promotes Corneal Graft Survival

Purpose

Corneal vascularization significantly increases the risk for graft rejection after keratoplasty. Semaphorin 3F (Sema3F) is a known modulator of physiologic avascularity in the outer retina. The aim of this study was to investigate whether Sema3F is involved in maintaining corneal avascularity and can reduce the risk for corneal graft rejection.

Methods

Corneal Sema3F expression was investigated using immunohistochemistry and qPCR in human and murine tissue. Pathologic invasion of blood and lymph vessels into corneal tissue was analyzed in the murine corneal suture and high-risk keratoplasty model. The anti-lymphangiogenic effects of Sema3F were further investigated using an in vitro spheroidal sprouting model with supernatant from isolated primary human corneal epithelial cells (hCECs).

Results

Sema3F is constitutively expressed in human and murine corneal epithelium. In the corneal suture model, lymphangiogenesis was significantly suppressed by topical Sema3F treatment (P = 0.0003). In the murine high-risk keratoplasty model, pretreatment by topical Sema3F in the inflammation phase significantly promoted subsequent graft survival (P = 0.0006). In this model, both lymph- and blood angiogenesis were reduced (P < 0.05). In vitro, hCEC supernatant had a direct anti-lymphangiogenic effect on human lymphatic endothelial cells (P < 0.01). This effect was completely abolished by addition of anti-Sema3F antibodies.

Conclusions

Sema3F is a novel mediator of corneal avascularity with potent anti-lymphangiogenic properties. Topical treatment with Sema3F eye drops may help to limit corneal vascularization and improve outcomes in high-risk keratoplasty patients.

Comparing Alternative Ranibizumab Dosages for Safety and Efficacy in Retinopathy of Prematurity: A Randomized Clinical Trial

IMPORTANCE

Anti-vascular endothelial growth factor (VEGF) therapies are a novel treatment option in retinopathy of prematurity (ROP). Data on dosing, efficacy, and safety are insufficient.

OBJECTIVE

To investigate lower doses of anti-VEGF therapy with ranibizumab, a substance with a significantly shorter systemic half-life than the standard treatment, bevacizumab.

DESIGN, SETTING, AND PARTICIPANTS

This randomized, multicenter, double-blind, investigator-initiated trial at 9 academic medical centers in Germany compared ranibizumab doses of 0.12 mg vs 0.20 mg in infants with bilateral aggressive posterior ROP; ROP stage 1 with plus disease, 2 with plus disease, or 3 with or without plus disease in zone I; or ROP stage 3 with plus disease in posterior zone II. Patients were recruited between September 2014 and August 2016. Twenty infants were screened and 19 were randomized.

INTERVENTIONS

All infants received 1 baseline ranibizumab injection per eye. Reinjections were allowed in case of ROP recurrence after at least 28 days.

MAIN OUTCOMES AND MEASURES

The primary end point was the number of infants who did not require rescue therapy at 24 weeks. Key secondary end points included time-to-event analyses, progression of physiologic vascularization, and plasma VEGF levels. Stages of ROP were photodocumented and reviewed by an expert committee.

RESULTS

Nineteen infants with ROP were enrolled (9 [47.4%] female; median [range] postmenstrual age at first treatment, 36.4 [34.7-39.7] weeks), 3 of whom died during the study (1 in the 0.12-mg group and 2 in the 0.20-mg group). Of the surviving infants, 8 (88.9%) (17 eyes [94.4%]) in the 0.12-mg group and 6 (85.7%) (13 eyes [92.9%]) in the 0.20-mg group did not require rescue therapy. Both ranibizumab doses were equally successful in controlling acute ROP (Cochran-Mantel-Haenszel analysis; odds ratio, 1.88; 95% CI, 0.26-13.49; P = .53). Physiologic intraretinal vascularization was superior in the 0.12-mg group. The VEGF plasma levels were not systematically altered in either group.

CONCLUSIONS AND RELEVANCE

This pilot study demonstrates that ranibizumab is effective in controlling acute ROP and that 24% of the standard adult dose (0.12 mg) appears equally effective as 40% (0.20 mg). Superior vascularization of the peripheral retina with 0.12 mg of ranibizumab indicates that the lower dose may be favorable. Unchanged plasma VEGF levels point toward a limited systemic drug exposure after ranibizumab.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02134457 and clinicaltrialsregister.eu Identifier: 2013-002539-13.

CNTF Attenuates Vasoproliferative Changes Through Upregulation of SOCS3 in a Mouse-Model of Oxygen-Induced Retinopathy

Purpose

Retinal vascular disease represents a major cause for vision loss in the Western world. Recent research has shown that neuronal and vascular damage are closely related in retinal disease. Ciliary neurotrophic factor (CNTF) is a well-studied neurotrophic factor that is currently being tested in clinical trials for the treatment of retinal degenerative diseases and macular telangiectasia. However, little is known about its effect on retinal vasculature. In this study, we investigate the effects of CNTF in retinal neovascular disease using the mouse model of oxygen-induced retinopathy (OIR).

Methods

Newborn pups were exposed to 75% oxygen from postnatal day (P)7 to P12 and subsequently returned to room air. Ciliary neurotrophic factor was injected intravitreally at OIR P12 and the vaso-obliterated and neovascular areas were quantified at OIR P17. Immunohistochemistry, RNA, and protein analysis were used to identify CNTF-responsive cells. In vitro experiments were performed to analyze the effect of CNTF on endothelial and astroglial cells.

Results

In the OIR model, CNTF facilitated capillary regrowth and attenuated preretinal neovascularization in a dose-dependent manner. The protective effect of CNTF was mediated via activation of the JAK/STAT3/SOCS3 signaling pathway. Immunohistochemical studies identified endothelial cells among others as CNTF-responsive cells in the retina. In vitro studies confirmed the anti-angiogenic effect of CNTF on endothelial cell sprouting.

Conclusions

This study provides evidence for a therapeutic potential of CNTF beyond degenerative retinal disease. Vasoproliferative retinopathies may benefit from a CNTF-dependent and SOCS3-mediated angiomodulatory effect.

Sema3f Protects Against Subretinal Neovascularization In Vivo

Pathological neovascularization of the outer retina is the hallmark of neovascular age-related macular degeneration (nAMD). Building on our previous observations that semaphorin 3F (Sema3f) is expressed in the outer retina and demonstrates anti-angiogenic potential, we have investigated whether Sema3f can be used to protect against subretinal neovascularization in two mouse models. Both in the very low-density lipid-receptor knockout (Vldlr^−/−) model of spontaneous subretinal neovascularization as well as in the mouse model of laser-induced choroidal neovascularization (CNV), we found protective effects of Sema3f against the formation of pathologic neovascularization. In the Vldlr^−/− model, AAV-induced overexpression of Sema3f reduced the size of pathologic neovascularization by 56%. In the laser-induced CNV model, intravitreally injected Sema3f reduced pathologic neovascularization by 30%. Combined, these results provide the first evidence from two distinct in vivo models for a use of Sema3f in protecting the outer retina against subretinal neovascularization.

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Sema3f is expressed in the physiologically avascular layers of the outer retina.

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Vldlr^−/− mice have reduced Sema3f and form spontaneous subretinal neovascularization.

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AAV-mediated increase of Sema3f protects against neovascularization in Vldlr^−/− mice.

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Sema3f also reduces pathologic neovascularization in eyes with laser-induced CNV.

Abnormal formation of new blood vessels in the retina is one of the hallmarks of a potentially blinding eye disease called wet (or exudative) macular degeneration. Here we investigated in two independent mouse models whether Sema3f (a protein involved in guiding blood vessel growth) can be modulated to protect against abnormal blood vessel growth. In both mouse models, we found protective effects of Sema3f against abnormal blood vessel formation in the retina. Combined, these results provide the first evidence that Sema3f could be modulated to protect against wet macular degeneration.

The German ROP Registry: data from 90 infants treated for retinopathy of prematurity

PURPOSE

The German retinopathy of prematurity (ROP) Registry collects data on treated ROP in a multicentre approach to analyse epidemiology and treatment patterns of severe ROP.

METHODS

Nine centres entered data from 90 treated ROP infants (born between January 2011 and December 2013) into a central database. Analysis included incidence rate of severe ROP, demographic data, stage of ROP, treatment patterns, recurrence rates, relevant comorbidities and ophthalmological or systemic complications associated with treatment.

RESULTS

Treatment rate for ROP was 3.2% of the screened population. The most frequent ROP stage at time of treatment was zone II, stage 3 +  (137 eyes). Treatment was bilateral in 97% of infants. Treatment patterns changed over time from 7% anti-vascular endothelial growth factor (VEGF) monotherapy in 2011 to 32% in 2014. Overall, laser treatment was the predominant treatment. However, all infants with zone I disease received anti-VEGF treatment. About 19% of infants required retreatment (16% of laser-treated and 21% of anti-VEGF treated infants). Mean time between first and second treatment was 3.8 weeks (± 11 days) for laser-treated and 10.4 weeks (± 60 days) for anti-VEGF-treated infants.

CONCLUSION

This study is the first multicentre analysis of severe ROP in Germany. The identified treatment patterns find laser as the most prevalent form of therapy, with an increasing use of anti-VEGF therapy over recent years. Recurrence rates were relatively high overall with slightly higher recurrence rates and later recurrence times in the anti-VEGF group. Anti-VEGF was predominantly used for high-risk stages like AP-ROP and zone I disease.

Pre-Analytical Parameters Affecting Vascular Endothelial Growth Factor Measurement in Plasma: Identifying Confounders

Background

Vascular endothelial growth factor-A (VEGF-A) is intensively investigated in various medical fields. However, comparing VEGF-A measurements is difficult because sample acquisition and pre-analytic procedures differ between studies. We therefore investigated which variables act as confounders of VEGF-A measurements.

Methods

Following a standardized protocol, blood was taken at three clinical sites from six healthy participants (one male and one female participant at each center) twice one week apart. The following pre-analytical parameters were varied in order to analyze their impact on VEGF-A measurements: analyzing center, anticoagulant (EDTA vs. PECT / CTAD), cannula (butterfly vs. neonatal), type of centrifuge (swing-out vs. fixed-angle), time before and after centrifugation, filling level (completely filled vs. half-filled tubes) and analyzing method (ELISA vs. multiplex bead array). Additionally, intrapersonal variations over time and sex differences were explored. Statistical analysis was performed using a linear regression model.

Results

The following parameters were identified as statistically significant independent confounders of VEGF-A measurements: analyzing center, anticoagulant, centrifuge, analyzing method and sex of the proband. The following parameters were no significant confounders in our data set: intrapersonal variation over one week, cannula, time before and after centrifugation and filling level of collection tubes.

Conclusion

VEGF-A measurement results can be affected significantly by the identified pre-analytical parameters. We recommend the use of CTAD anticoagulant, a standardized type of centrifuge and one central laboratory using the same analyzing method for all samples.

Legionella species of different human prevalence induce different rates of apoptosis in human monocytic cells

Legionella species of different human prevalence were examined with respect to induction of apoptosis in the human monocytic cell line Mono Mac 6 (MM6). L. pneumophila serogroup 1 (Pontiac), L. pneumophila serogroup 1 (Philadelphia-1), L. longbeachae serogroup 1, L. gormanii, L. micdadei and L. steigerwaltii were used to infect MM6 cells. Subsequent induction of apoptosis was investigated by enzyme-linked immunosorbent assay (ELISA), gel electrophoresis of cellular DNA extracts, and staining of cells with the DNA dye 4', 6-diamidino-2-phenylindole (DAPI). Additionally, the concomitant occurrence of infection and apoptosis was demonstrated by a combination of immunohistochemistry with nuclear DAPI counterstaining. Induction of apoptosis in MM6 cells by a given species of the genus Legionella correlates with their human prevalence rather than with their ability to multiply within this human monocytic cell line. Furthermore, we found that initiation of apoptosis of Mono Mac 6 cells was dependent on direct adherence of the pathogenic bacteria to the host cell and was triggered by extracellular bacteria.