The US national registry for childhood interstitial and diffuse lung disease: Report of study design and initial enrollment cohort.

INTRODUCTION: Childhood interstitial and diffuse lung disease (chILD) encompasses a broad spectrum of rare disorders. The Children's Interstitial and Diffuse Lung Disease Research Network (chILDRN) established a prospective registry to advance knowledge regarding etiology, phenotype, natural history, and management of these disorders. METHODS: This longitudinal, observational, multicenter registry utilizes single-IRB reliance agreements, with participation from 25 chILDRN centers across the U.S. Clinical data are collected and managed using the Research Electronic Data Capture (REDCap) electronic data platform. RESULTS: We report the study design and selected elements of the initial Registry enrollment cohort, which includes 683 subjects with a broad range of chILD diagnoses. The most common diagnosis reported was neuroendocrine cell hyperplasia of infancy, with 155 (23%) subjects. Components of underlying disease biology were identified by enrolling sites, with cohorts of interstitial fibrosis, immune dysregulation, and airway disease being most commonly reported. Prominent morbidities affecting enrolled children included home supplemental oxygen use (63%) and failure to thrive (46%). CONCLUSION: This Registry is the largest longitudinal chILD cohort in the United States to date, providing a powerful framework for collaborating centers committed to improving the understanding and treatment of these rare disorders.

Risk finance for catastrophe losses with Pareto-calibrated Lévy-stable severities.

For catastrophe losses, the conventional risk finance paradigm of enterprise risk management identifies transfer, as opposed to pooling or avoidance, as the preferred solution. However, this analysis does not necessarily account for differences between light- and heavy-tailed characteristics of loss portfolios. Of particular concern are the decreasing benefits of diversification (through pooling) as the tails of severity distributions become heavier. In the present article, we study a loss portfolio characterized by nonstochastic frequency and a class of Lévy-stable severity distributions calibrated to match the parameters of the Pareto II distribution. We then propose a conservative risk finance paradigm that can be used to prepare the firm for worst-case scenarios with regard to both (1) the firm's intrinsic sensitivity to risk and (2) the heaviness of the severity's tail.

Imaging Retinal Vascular Changes in the Mouse Model of Oxygen-Induced Retinopathy.

PURPOSE: Oxygen-induced retinopathy in the mouse is the standard experimental model of retinopathy of prematurity. Assessment of the pathology involves in vitro analysis of retinal vaso-obliteration and retinal neovascularization. The authors studied the clinical features of oxygen-induced retinopathy in vivo using topical endoscopy fundus imaging (TEFI), in comparison to standard investigations, and evaluated a system for grading these features. METHODS: Postnatal day (P)7 mice were exposed to 75% oxygen for five days to induce retinopathy or maintained in room air as controls. Retinal vascular competence was graded against standard photographs by three masked graders. Retinal photographs were obtained at predetermined ages using TEFI. Postmortem, retinal vaso-obliteration was measured in whole mounts with labeled vasculature, and retinal neovascularization was quantified in hematoxylin- and eosin-stained ocular cross sections. RESULTS: Fundus photography by TEFI was possible from P15, when retinal vascular incompetence, including dilatation and tortuosity, was significant in mice with oxygen-induced retinopathy in comparison to controls. Vascular incompetence peaked in severity at P17 and persisted through P25. Comparison with in vitro analyses indicated that vascular changes were most severe after retinal avascularity had begun to decrease in area, and coincident with the maximum of retinal neovascularization. A weighted Fleiss-Cohen kappa indicated good intra- and interobserver agreement for a 5-point grading system. CONCLUSIONS: Topical endoscopy fundus imaging demonstrates retinal vascular incompetence in mice with oxygen-induced retinopathy. The technique complements standard postmortem analysis for following the course of the model. TRANSLATIONAL RELEVANCE: Topical endoscopy fundus imaging has application in the evaluation of novel biologic drugs for retinopathy of prematurity.

Altered vascular expression of EphrinB2 and EphB4 in a model of oxygen-induced retinopathy.

EphrinB2 ligands and EphB4 receptors are expressed on endothelial cells (EC) of arteries and veins, respectively, and are essential for vascular development. To understand how these molecules regulate retinal neovascularization (NV), we evaluated their expression in a model of oxygen-induced retinopathy (OIR). EphrinB2 and EphB4 were expressed on arterial and venous trunks, respectively, and on a subset of deep capillary vessels. EphB4 expression was reduced following hyperoxia, while ephrinB2 expression remained unaltered. In addition, a subset of EphB4-positive veins regressed in a caspase-3-dependent manner during hyperoxia. Arteriovenous malformations were also observed with loss of arterial-venous boundaries. Finally, both ephrinB2 and EphB4 were expressed on a subset of neovascular tufts following hyperoxia. These data confirm the contribution of ECs from both venous and arterial origins to the development of retinal NV.

TRAIL-deficient mice exhibit delayed regression of retinal neovascularization.

While it is well established that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in various cell types, the role of TRAIL in regulation of retinal neovascularization (NV) has not been described. Here we determined the role of TRAIL in retinal NV during oxygen-induced retinopathy using TRAIL deficient ((-/-)) mice. TRAIL and its receptor, DR5, were expressed in wild-type retinas at all time points evaluated (postnatal days 12, 17, 21, 24) during oxygen-induced retinopathy and in age-matched room air control animals. Localization of TRAIL(+) cells within the neovascular tufts of hyperoxia- exposed wild-type mice suggested TRAIL plays a role in oxygen-induced retinopathy. Retinal vascular development appeared normal in the TRAIL(-/-) mice, except for a small but significant difference in the capillary-free zone surrounding major arteries. A minimal difference in avascularity was observed at postnatal day 12 in the retinas of TRAIL(-/-) mice after hyperoxia-exposure compared with wild-type mice, suggesting that TRAIL does not play a major role in the vaso-obliterative phase of oxygen-induced retinopathy. However, at the peak of NV, TRAIL(-/-) mice had a significant increase in retinal neovascularization. In addition, when NV naturally regresses in wild-type mice, TRAIL(-/-) mice continued to display significantly high levels of NV. This was attributed to a significant decrease in neovascular tuft cells undergoing apoptosis in TRAIL(-/-) mice. Together, these data strongly suggest that TRAIL plays a role in the control of retinal NV.

Soluble ephrin-B2 mediates apoptosis in retinal neovascularization and in endothelial cells.

PURPOSE: EphB4 receptors and their ephrinB2 ligands are essential for vascular development, but also play a role in pathological neovascularization (NV). We previously reported that soluble (s) forms of EphB4 and ephrinB2 significantly reduced retinal NV in a model of oxygen-induced retinopathy. This study investigates if these molecules suppress retinal NV by stimulation of endothelial cell (EC) apoptosis. METHODS: C57BL/6 mice at postnatal day 7 (P7) were exposed to 75% oxygen for 5 days (P12) and allowed to recover in room air to induce retinal NV. One eye was injected intravitreally with 150 ng in 1.5 microL of sEphB4 or sEphrinB2 on P12 and P14, while contralateral eyes were injected with IgG antibody as control. Eyes were enucleated for histological analysis. At P16 TUNEL analysis and caspase-3 immunohistochemistry was performed on retinal sections to compare the apoptotic response between sEphB4 or sEphrinB2 injected eyes and controls. In vitro studies were performed with human retinal microvascular EC (HREC). RESULTS: Quantification of TUNEL positive vascular cells, located in areas of retinal NV, revealed approximately 2.5-fold increase in apoptosis in sEphrinB2 injected eyes compared to control eyes. Immunohistochemistry studies revealed co-localization of both TUNEL positive cells and caspase-3 positive cells with the endothelial marker, von Willebrand factor. Cultured HREC demonstrated significantly higher caspase-3 activity after a 3 h stimulation with sEphrinB2+/-VEGF compared to IgG control+/-VEGF (P<0.005). sEphB4 stimulation had no significant effect on caspase-3 activity in HREC cultures. CONCLUSIONS: These data suggest that modulation of the endogenous ephrin signaling mechanism by sEphrinB2 may induce suppression of retinal NV via induction of apoptosis. Results of the in vitro studies suggest that sEphrinB2 may directly induce apoptosis of EC during pathological neovascularization.

MCP-1 deficiency delays regression of pathologic retinal neovascularization in a model of ischemic retinopathy.

PURPOSE: The present study investigates whether retinal neovascularization (NV) and apoptosis are altered in MCP-1-deficient ((-/-)) mice in the OIR model. METHODS: Postnatal day (P) 7 MCP-1(-/-) and C57BL/6 (B6) mice were exposed to 75% oxygen for 5 days and then recovered in room air. Immunostaining was performed to localize macrophages/microglia within retinal whole mounts and cross-sections. Retinopathy was qualitatively assessed in FITC-dextran-perfused retinas, and preretinal NV was quantified on P17, P21, and P24. TUNEL analysis was used to compare apoptosis between B6 and MCP-1(-/-) mice. RESULTS: MCP-1(-/-) and B6 mice revealed normal vascular development in room air controls and similar vaso-obliteration in oxygen-exposed mice on P12. MCP-1(-/-) mice exhibited significantly reduced vascular tuft-associated F4/80(+) cells compared with B6 mice. FITC-dextran-perfused retinas exhibited prominent neovascular tufts on P17, and quantification of preretinal nuclei revealed no significant differences between MCP-1(-/-) and B6 mice. In contrast, on P21 and P24, MCP-1(-/-) mice exhibited significant increases in preretinal neovascular nuclei compared with B6 controls. These increases in NV in the MCP-1(-/-) mice were associated with a significant reduction in vascular tuft apoptosis. CONCLUSIONS: The results demonstrate that the absence of MCP-1 does not alter normal retinal vascular development. Furthermore, MCP-1(-/-) mice exhibit a similar neovascular response on P17. However, the reduction in tuft-associated macrophages/microglia in the MCP-1(-/-) mice correlates with reduced vascular tuft apoptosis and delayed regression of retinal NV. These findings suggest that macrophages/microglia may contribute to tuft regression through their proapoptotic properties.

Identification of novel alternatively spliced isoforms of RTEF-1 within human ocular vascular endothelial cells and murine retina.

PURPOSE: Identification of transcription factors that regulate the transcription of the vascular endothelial growth factor (VEGF) gene may facilitate understanding of the etiology and progression of ocular neovascular diseases. The purpose of this study was to determine whether transcriptional enhancer factor 1-related (RTEF-1) was present within ocular vascular endothelial cells and whether it played a role in the control of the transcription of the VEGF gene. METHODS: Primary cultures of human retinal vascular endothelial cells (RVECs) were maintained under normoxic or hypoxic conditions before isolation of mRNA. RT-PCR was performed to detect RTEF-1 transcripts. Amplified products were cloned into an expression plasmid. Human VEGF promoter and deletion constructs were cloned into a pSEAP reporter vector. Various RTEF-1 isoforms and VEGF promoter constructs were coelectroporated into human cells, and reporter expression levels were determined. Retinal tissue from a mouse model of retinopathy of prematurity (ROP) was analyzed by RT-PCR for the presence of RTEF-1 transcripts. RESULTS: Full-length 1305-bp and novel 936-bp RTEF-1 transcripts were identified in cultured human RVECs under normoxic conditions. A novel 447-bp isoform was present in cells maintained in a hypoxic environment. Four of the 11 translated exons predicted to code for the 1305-bp product were spliced out of the 936-bp transcript. The 1305-bp product enhanced expression from the VEGF promoter 4-fold greater than background, whereas the 936-bp and the 447-bp isoforms enhanced expression 3x and 12x, respectively. Analysis with deletion promoter constructs determined that all isoforms required the presence of Sp1 elements for efficient activation and that the hypoxia response element (HRE) was not essential for enhancement. Transcripts for novel RTEF-1 isoforms were also identified in neural retinal tissue of mice. Different murine-specific isoforms were present at different stages of postnatal development. CONCLUSIONS: Novel RTEF-1 transcripts are present within human ocular vascular endothelial cells and mouse neural retina during normal and ROP development, and alternatively spliced products are produced under hyperoxic and hypoxic conditions. Alternative spliced variants of human RTEF-1 transcripts are able to potentiate expression from the VEGF 5' proximal promoter region.

Unique gene expression profiles of donor-matched human retinal and choroidal vascular endothelial cells.

PURPOSE: Consistent with clinical observations that posterior uveitis frequently involves the retinal vasculature and recent recognition of vascular heterogeneity, the hypothesis for this study was that retinal vascular endothelium was a cell population of unique molecular phenotype. METHODS: Donor-matched cultures of primary retinal and choroidal endothelial cells from six human cadavers were incubated with either Toxoplasma gondii tachyzoites (10:1, parasites per cell) or Escherichia coli lipopolysaccharide (100 ng/mL); control cultures were simultaneously incubated with medium. Gene expression profiling of endothelial cells was performed using oligonucleotide arrays containing probes designed to detect 8746 human transcripts. After normalization, differential gene expression was assessed by the significance analysis of microarrays, with the false-discovery rate set at 5%. For selected genes, differences in the level of expression between retinal and choroidal cells were evaluated by real-time RT-PCR. RESULTS: Graphic descriptive analysis demonstrated a strong correlation between gene expression of unstimulated retinal and choroidal endothelial cells, but also highlighted distinctly different patterns of expression that were greater than differences noted between donors or between unstimulated and stimulated cells. Overall, 779 (8.9%) of 8746 transcripts were differentially represented. Of note, the 330 transcripts that were present at higher levels in retinal cells included a larger percentage of transcripts encoding molecules involved in the immune response. Differential gene expression was confirmed for 12 transcripts by RT-PCR. CONCLUSIONS: Retinal and choroidal vascular endothelial cells display distinctive gene expression profiles. The findings suggest the possibility of treating posterior uveitis by targeting specific interactions between the retinal endothelial cell and an infiltrating leukocyte.

Microglia and macrophages are increased in response to ischemia-induced retinopathy in the mouse retina.

PURPOSE: The ability of microglial cells (MG) and macrophages (MAC) to release cytokines, induce apoptosis, as well as perform phagocytic functions suggests a possible role in wound healing following oxygen-induced injury. This study was performed to determine the temporal and spatial expression of F4/80 (F4/80+) positive microglia/macrophages (MG/MAC) in areas of retinal damage in the mouse model of oxygen-induced retinopathy. METHODS: C57BL/6 postnatal day 7 (P7) mice were exposed to 75% O2 for 5 days (P12) then allowed to recover in room air. Hyperoxia-exposed (O2) mice (O2 refers to hyperoxia exposure from P7 to P12 only) were sacrificed on P12, P14, P17, and P21 and their eyes were examined. Localization of F4/80+ cells in FITC-dextran-perfused retinas allowed coordinate visualization of retinal vessels and MG/MAC via fluorescence microscopy. BrdU, a cellular proliferation marker, was injected intraperitoneally 1 h prior to sacrifice. Immunostaining was performed for a microglia and macrophage-specific antigen (F4/80) and BrdU. CCL2 (monocyte chemoattractant protein-1; MCP-1) expression was examined by quantitative real time reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: There was a marked increase (>500%) in MG/MAC in hyperoxia-exposed retinas on P17O2 and P21O2 compared to control retinas. At P17O2, MG/MAC were localized in areas of neovascularization (NV), revealing an intimate relationship between MG/MAC and neovascular tufts. However, P21O2 retinas demonstrated MG/MAC associated with avascular regions in the outer layers of the retina. Immunostaining for F4/80 and BrdU revealed rare co-localization in hyperoxia-exposed retinas. Real time RT-PCR results demonstrated increased expression of CCL2 in P14O2- and P17O2- exposed retinas. CONCLUSIONS: Our results suggest that resident retinal microglia proliferation occurs at a low frequency in response to injury in this model. The substantial increase in total F4/80+ cells in hyperoxia-exposed retinas in conjunction with the upregulation of CCL2 is consistent with recruitment of hematogenous macrophages into the retina. The temporal and spatial localization of MG/MAC adjacent to neovascular tufts suggests these cells are modulating the retinal response to ischemia-induced retinopathy.

Altered retinal neovascularization in TNF receptor-deficient mice.

PURPOSE: Tumor necrosis factor alpha (TNF-alpha) has been shown to play an integral role in inflammation, apoptosis, and angiogenesis. We induced retinopathy in tumor necrosis factor receptor-deficient mice (TNFR-) in order to examine the role TNF-alpha plays in the pathogenesis of retinopathy of prematurity. METHODS: On postnatal day (P) 7, TNFR-knockout mice and their congenic controls, B6129JF1 (B6129) mice, were exposed to 75% oxygen for up to 5 days and then allowed to recover in room air. Retinopathy was qualitatively assessed by examining fluorescein (FITC) angiography. Furthermore, retinal vascular changes were quantified by immunolabeling retinal vessels in cross sections with an anti-type IV collagen antibody. Disease pathology was quantified by counting preretinal neovascular nuclei. TUNEL analysis was performed to determine if TNFR-mice exhibited a reduced number of apoptotic cells after oxygen-induced retinopathy. RESULTS: FITC-perfused retinas qualitatively demonstrated similar degrees of vascular development and vaso-obliteration on P12 in the room air and hyperoxia-exposed TNFR- and B6129 mice. On P17, the hyperoxia-exposed TNFR- and B6129 mice qualitatively appeared to develop a similar degree of retinal neovascularization. However, FITC-perfused retinal flat mounts on P21 suggested that the hyperoxia-exposed TNFR-mice had a prolonged neovascular response compared to the hyperoxia-exposed B6129 mice. Type IV collagen staining revealed delayed development of the deep intraretinal vessels in the TNFR-room control mice and hyperoxia-exposed TNFR-mice, as compared with B6129 controls. On P17, the average number of preretinal nuclei was similar between the hyperoxia-exposed TNFR-mice and B6129 mice. However, on P21, the neovascularization in the B6129 mice had regressed (3.9 +/- 0.57, preretinal nuclei), whereas neovascularization in the TNFR-mice remained prominent (25.6 +/- 6.3, preretinal nuclei). On P21, the B6129 mice exhibited increased apoptosis in preretinal vascular tufts as compared with TNFR- mice. CONCLUSIONS: TNFR- mice had both an altered development of the intraretinal vessels and altered angiogenic response after hyperoxia. Therefore, absence of the TNF-alpha pathway appears to disrupt the local microenvironment promoting angiogenesis in the deep retinal vascular network, as well as altering tuft regression by modifying endothelial cell apoptosis.

Increased expression of chemokine KC, an interleukin-8 homologue, in a model of oxygen-induced retinopathy.

PURPOSE: The purpose of this study was to determine the retinal expression of angiogenic chemokines/cytokines in a mouse model of oxygen-induced retinopathy. METHODS: C57BL/6 (B6) mice were exposed to 75% oxygen from postnatal day 7 (P7) to P12 and then recovered in room air. Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine relative mRNA levels of KC, macrophage inflammatory protein-2 (MIP-2), interleukin-1alpha (IL-1alpha), and interferon gamma (IFN-gamma). Immunohistochemistry was used to localize KC in the retina. IL-1alpha was also injected into the vitreous of mouse eyes, and KC expression was examined by RT-PCR, enzyme-linked immunosorbent assay (ELISA), and immunohistochemistry. RESULTS: KC expression at both the mRNA and protein levels was increased in P14, P17, and P21 of hyperoxia-injured eyes. KC immunoreactivity was localized along the nerve fiber layer and in radial Müller cell processes. IL-1alpha mRNA was modestly increased in hyperoxia-injured eyes on P14 and P17. INF-gamma mRNA was not detected in the retina. Adult mouse eyes injected with IL-1alpha demonstrated increased levels of both KC mRNA and protein, with KC immunoreactivity localized to Müller cell processes. CONCLUSIONS: Oxygen-induced injury to the developing retina results in the induction of the CXC chemokine KC at both the mRNA and protein levels during the peak time points of neovascularization, suggesting a possible role in the pathogenesis of retinopathy of prematurity.

Soluble forms of EphrinB2 and EphB4 reduce retinal neovascularization in a model of proliferative retinopathy.

PURPOSE: Ephrin ligands and their Eph receptors are key regulators of endothelial cell (EC) proliferation, migration, adhesion, and repulsion during mammalian vascular development. The hypothesis was that these molecules also play a role in pathologic neovascularization (NV) in the mouse model of oxygen-induced retinopathy. METHODS: C57BL/6 mice at postnatal day (P)7 were exposed to 75% oxygen (O(2)) for 5 days (until P12) and allowed to recover in room air to induce retinal NV. Retinas from unexposed and hyperoxia-exposed mice between P7 to P24 were analyzed specifically for EphrinB2 and EphB4 transcript expression by RT-PCR. Phospho-Eph (p-Eph) receptor was evaluated during active EC proliferation at P15 and P17 by immunohistology. Some hyperoxia-exposed mice had one eye injected intravitreally with 150 ng/1.5 microL of soluble EphrinB2/Fc or EphB4/Fc chimeras during transition from high O(2) to room air (P12) and injected again on P14. Contralateral eyes were injected with human IgG as the control. Preretinal nuclei and retinal blood vessels were quantified at peak disease (P17). RESULTS: EphrinB2 mRNA was constitutively expressed in the developing retina and was unchanged by hyperoxia. In contrast, EphB4 mRNA expression was modulated during normal retinal development and was altered by hyperoxia. Furthermore, p-Eph was detected in developing preretinal tufts, thus implying that Ephrin/Eph signaling system is active in this experimental model. Intravitreal injection of soluble versions of these molecules significantly reduced pathologic neovascularization. The number of preretinal nuclei in hyperoxia-treated mice was reduced by 66% (P < 0.05) in EphrinB2-injected eyes, whereas EphB4 treatment yielded a 69% reduction (P < 0.05), compared with control injections. Intraretinal vessel development was not altered by the injections. CONCLUSIONS: These results support the hypothesis that endogenous EphrinB2 and EphB4 are regulators of retinal NV during oxygen-induced retinopathy and may be useful targets for therapeutic intervention.

Increased retinal neovascularization in Fas ligand-deficient mice.

PURPOSE: To investigate whether the absence of the Fas-Fas ligand system of apoptosis regulation affects hyperoxia-induced retinal vaso-obliteration and retinal neovascularization in a mouse model of oxygen-induced retinopathy. METHODS: C57BL/6 (B6) and congenic Fas ligand-deficient generalized lymphoproliferative disease (gld) mice were exposed to 75% oxygen from postnatal day (P)7 to P12 and then allowed to recover in room air. Eyes obtained from P7, P8, P10, P12, P14, P17, and P21, from both hyperoxia-injured and room air control animals were processed for histopathologic examination. Retinopathy was also qualitatively assessed in FITC-dextran perfused retinas by fluorescence microscopy. TUNEL assays were used to compare apoptosis in B6 and gld mice. Intraretinal blood vessel formation was quantitated by immunolabeling with an anti-type-IV collagen antibody. Retinopathy was further assessed by quantitation of preretinal neovascular nuclei on P17. RT-PCR was used to examine retinal expression of Fas and Fas ligand (FasL) over a time course of hyperoxia-induced retinopathy. RESULTS: In hyperoxia-injured mice, the same degree of vaso-obliteration was apparent on P8, P10, and P12 in B6 and gld mice. By P17, the hyperoxia-exposed FITC-perfused retinas of both strains exhibited preretinal neovascular tufts. However, P17 gld hyperoxia-exposed retinas exhibited approximately a 50% increase in preretinal neovascular nuclei compared with B6 mice. In addition, a subset of apoptotic cells located solely within the neovascular tufts on P17 were significantly decreased in hyperoxia-exposed gld retinas, compared with B6 control animals. RT-PCR showed an increase in the expression levels of Fas in both strains of mice as a result of hyperoxia-induced injury. CONCLUSIONS: These data suggest that the Fas-FasL interaction plays an important role in retinal neovascularization after hyperoxia-induced injury. The absence of functional FasL leads to an increased incidence of preretinal neovascular nuclei and decreased retinal apoptosis suggesting that this pathway may serve as a means of regulating endogenous endothelial cell populations in pathologic angiogenesis.