Publications

2016

Yao W, Sedaghat A, Yadav P, Fay A, Metson R. Orbital Decompression in the Endoscopic Age: The Modified Inferomedial Orbital Strut.. Otolaryngol Head Neck Surg. 2016;154(5):963–9.

OBJECTIVE: Postoperative diplopia occurs in up to 45% of patients following orbital decompression for exophthalmos associated with Graves' orbitopathy. We sought to describe outcomes of our balanced orbital decompression strategy that includes the preservation of a modified inferomedial orbital strut (mIOS). STUDY DESIGN: Case series with chart review. SETTING: Academic medical center. SUBJECTS AND METHODS: A total of 115 consecutive orbital decompressions were performed on 73 patients (42 bilateral) with Graves' orbitopathy. All patients underwent (1) a balanced decompression technique incorporating an endoscopic medial and external lateral decompression and (2) a mIOS technique with preservation of the anterior half of the inferomedial orbital strut. A periorbital periosteal (orbital) sling was utilized in patients (n = 54) without threatened vision loss, proptosis >28 mm, or periorbital disruption to prevent prolapse of the medial rectus muscle. RESULTS: Utilization of the mIOS technique with or without a sling did not adversely affect the reduction in proptosis (5.1 mm with sling vs 5.0 mm without sling; P = .85).The incidence of new-onset postoperative diplopia was 17% (n = 6). The sling was not associated with postoperative diplopia (odds ratio = 0.54, 95% confidence interval: 0.08-3.40, P = .51), while it was associated with resolution of preexisting diplopia (odds ratio = 6.67, 95% confidence interval: 1.06-42.06, P = .04). No intraoperative complications occurred, and no patients suffered a decrement in visual acuity. CONCLUSION: Balanced orbital decompression utilizing a mIOS in patients with Graves' orbitopathy provides a safe and effective reduction in proptosis with a low rate of new-onset diplopia as compared with historical values. Utilization of an orbital sling may be beneficial in reducing postoperative diplopia in select patients.

Robert MC, Frenette M, Zhou C, Yan Y, Chodosh J, Jakobiec F, Stagner A, Vavvas D, Dohlman C, Paschalis E. A Drug Delivery System for Administration of Anti-TNF-α Antibody.. Transl Vis Sci Technol. 2016;5(2):11.

PURPOSE: To describe the fabrication, evaluation, and preliminary in vivo safety of a new drug delivery system (DDS) for topical anti-TNF-α antibody administration. METHODS: A DDS was fabricated using inverse template fabrication of a hydrophobic three-dimensional porous scaffold (100-300 μm in diameter porosity) loaded with 10% polyvinyl alcohol hydrogel carrying 5 mg/ml (weight/volume) of anti-TNF-α antibody. Drug-loaded DDS was sterilized with 25 kGy of gamma irradiation. Long-term in vitro antibody affinity and release was evaluated at room temperature or 37°C using enzyme-linked immunosorbent assay (ELISA) and protein fluorescence. In vivo clinical and histolopathological assessment was performed by subcutaneous implantation in BALB/c mice for 3 months. RESULTS: Gamma irradiation, repeated dry/wet cycles, and storage at room temperature for 1 year or 37°C for 1 month had no deleterious effects on antibody affinity. Anti-TNF-α release was high during the first minutes of aqueous exposure, followed by stabilization and gradual, low-dose, antibody release over the next 30 days. Histopathologic evaluation of explanted DDS showed a fibrous pseudocapsule and a myxoid acute/chronic inflammation without granuloma formation surrounding the implants. CONCLUSIONS: Sustained local delivery of anti-TNF-α antibody is feasible using the described DDS, which provides stability of the enclosed antibody for up to 1 year of storage. Preliminary results show good in vivo tolerance following subcutaneous placement for 3 months. The proposed fabrication and sterilization process opens new possibilities for the delivery of biologic agents to the anterior surface of the eye. TRANSLATIONAL RELEVANCE: The described DDS will facilitate the treatment of ocular surface diseases amenable to biologic therapy.

Miller J. VEGF: From Discovery to Therapy: The Champalimaud Award Lecture.. Transl Vis Sci Technol. 2016;5(2):9.

PURPOSE: Intraocular vascular diseases are leading causes of adult vision loss, and in the mid-1900s, I. C. Michaelson postulated that the retina releases a soluble, diffusible factor that causes abnormal vascular growth and leakage. What became known as "Factor X" eluded investigators for decades. METHODS: The field of cancer research, where Judah Folkman pioneered the concept of angiogenesis, provided the inspiration for the work honored by the 2014 Champalimaud Vision Award. Recognizing that tumors recruit their own blood supply to achieve critical mass, Dr Folkman proposed that angiogenic factors could be therapeutic targets in cancer. Napoleone Ferrara identified vascular endothelial growth factor (VEGF) as such an angiogenic agent: stimulated by hypoxic tumor tissue, secreted, and able to induce neovascularization. VEGF also was a candidate for Factor X, and the 2014 Champalimaud Laureates and colleagues worked individually and collaboratively to identify the role of VEGF in ocular disease. RESULTS: The Champalimaud Laureates correlated VEGF with ocular neovascularization in animal models and in patients. Moreover, they showed that VEGF not only was sufficient, but it also was required to induce neovascularization in normal animal eyes, as VEGF inhibition abolished ocular neovascularization in key animal models. CONCLUSIONS: The identification of VEGF as Factor X altered the therapeutic paradigms for age-related macular degeneration (AMD), diabetic retinopathy, retinal vein occlusion, and other retinal disorders. TRANSLATIONAL RELEVANCE: The translation of VEGF from discovery to therapy resulted in the most successful applications of antiangiogenic therapy to date. Annually, over one million patients with eye disease are treated with anti-VEGF agents.

Tahvildari M, Omoto M, Chen Y, Emami-Naeini P, Inomata T, Dohlman T, Kaye A, Chauhan S, Dana R. In Vivo Expansion of Regulatory T Cells by Low-Dose Interleukin-2 Treatment Increases Allograft Survival in Corneal Transplantation.. Transplantation. 2016;100(3):525–32.

BACKGROUND: Corneal allograft survival dramatically decreases in hosts with inflamed or vascularized recipient beds. We have previously shown that in rejected corneal allografts regulatory T cells (Treg) demonstrate diminished Foxp3 expression and immunoregulatory function. Treatment with low doses of IL-2 selectively expands Treg and has been proposed for the treatment of autoimmune diseases. In this study, we investigated the effect of low-dose IL-2 administration on Treg function and corneal allograft survival. METHODS: Allogeneic corneal transplantation was performed on inflamed host beds. Low-dose systemic IL-2 was administered starting 3 days before grafting until 6 weeks after transplantation. Frequencies of Treg and their immunosuppressive function and antigen specificity were assessed using flow cytometry, in vitro proliferation assays, and adoptive transfer experiments. Frequencies of effector T cells (Teff) and graft infiltrating immune cells were measured at 2 weeks posttransplantation. Long-term allograft survival was evaluated for up to 9 weeks using Kaplan-Meier survival analysis. RESULTS: Treatment with low-dose IL-2 significantly increased frequencies of CD4CD25Foxp3 Treg and their immunosuppressive function. It also suppressed alloimmune response as shown by the decreased CD4 IFNγ T cell frequencies and graft infiltration of CD45 and CD4 cells. Clinical evaluation of the grafts showed significant improvement in long-term corneal allograft survival in the IL-2 treated group compared with controls. CONCLUSIONS: Our study is the first to report that treatment with low-dose IL-2 increases survival of corneal allografts. We propose that IL-2-mediated Treg expansion can be an effective tool to prevent alloimmunity and to improve long-term allograft survival in transplantation.

PURPOSE: To evaluate the short-term changes in ocular surface measures and tear inflammatory mediators after femtosecond lenticule extraction (FLEx) and small-incision lenticule extraction (SMILE) procedures. METHODS: Eighteen subjects (18 eyes) underwent FLEx and 23 subjects (23 eyes) underwent SMILE in this single-center and prospective study. Central corneal sensitivity, Schirmer I test (SIT), noninvasive tear breakup time (NI-TBUT), tear meniscus height, corneal fluorescein (FL) staining, and ocular surface disease index (OSDI) were assessed in all patients. Concentrations of interleukin-1α (IL-1α), tumor necrosis factor-α (TNF-α), nerve growth factor (NGF), interferon-γ (IFN-γ), transforming growth factor-β1 (TGF-β1) and matrix metalloproteinase-9 (MMP-9) in collected tears were measured by multiplex antibody microarray. RESULTS: Central corneal sensitivity was reduced in both groups, but the scores in the SMILE group were higher than those in the FLEx group at all time points postoperatively (P<0.01). Lower FL scores and longer NI-BUT were observed in the SMILE group 1 week after surgery (P<0.05). OSDI scores in both groups increased rapidly at 1 day and 1 week postoperatively, then returned to their preoperative levels within 1 month (P<0.05). There were no significant differences in SIT or tear meniscus height between the two groups. Lower and faster recovery of tear NGF, TGF-β1 and IL-1α concentration were found in the SMILE group compared to the FLEx group postoperatively. No significant difference was found in tear TNF-α, IFN-γ and MMP-9 for either group before or after surgery. Tear NGF, TGF-β1 and IL-1α show a correlation with ocular surface changes after FLEx or SMILE surgery. CONCLUSION: SMILE has superiority over FLEx in early ocular surface changes and NGF, TGF-β1 and IL-1α may contribute to the process of ocular surface recovery. TRIAL REGISTRATION: ClinicalTrials.gov NCT02540785.

Dohlman T, Di Zazzo A, Omoto M, Hua J, Ding J, Hamrah P, Chauhan S, Dana R. E-Selectin Mediates Immune Cell Trafficking in Corneal Transplantation.. Transplantation. 2016;100(4):772–80.

BACKGROUND: Immune rejection continues to threaten all tissue transplants. Here we sought to determine whether platelet (P)- and endothelial (E)-selectin mediate T cell recruitment in corneal transplantation and whether their blockade can reduce T cell graft infiltration and improve long-term corneal allograft survival. METHODS: In a murine model of allogeneic corneal transplantation, we used PCR and immunohistochemistry to investigate expression of P- and E-selectin in rejected versus accepted allografts and lymph node flow cytometry to assess expression of selectin ligands by effector T cells. Using P- and E-selectin neutralizing antibodies, we evaluated the effect of blockade on CD4 T cell recruitment, as well as the effect of anti-E-selectin on long-term allograft survival. RESULTS: The P- (93.3-fold, P < 0.05) and E-selectin (17.1-fold, P < 0.005) are upregulated in rejected versus accepted allogeneic transplants. Type 1 T helper cells from hosts with accepted and rejected grafts express high levels of P-selectin glycoprotein ligand 1 and glycosylated CD43. In vivo blockade of P (0.47 ± 0.03, P < 0.05) and E selectin (0.49 ± 0.1, P < 0.05) reduced the number of recruited T cells compared with IgG control (0.98 ± 0.1). Anti-E-selectin reduced the number of mature antigen-presenting cells trafficking to lymphoid tissue compared with control (6.96 ± 0.9 vs 12.67 ± 0.5, P < 0.05). Anti-E-selectin treatment delayed graft rejection and increased survival compared with control, although this difference did not reach statistical significance. CONCLUSIONS: In a model of corneal transplantation, P- and E-selectin mediate T cell recruitment to the graft, E-selectin mediates APC trafficking to lymphoid tissue, and blockade of E-selectin has a modest effect on improving long-term graft survival.

OBJECTIVE: To provide artificially-elicited vision that is temporally dynamic, retinal prosthetic devices will need to repeatedly stimulate retinal neurons. However, given the diversity of physiological types of retinal ganglion cells (RGCs) as well as the heterogeneity of their responses to electric stimulation, temporal properties of RGC responses have not been adequately investigated. Here, we explored the cell type dependence of network-mediated RGC responses to repetitive electric stimulation at various stimulation rates. APPROACH: We examined responses of ON and OFF types of RGCs in the rabbit retinal explant to five consecutive stimuli with varying inter-stimulus intervals (10-1000 ms). Each stimulus was a 4 ms long monophasic sinusoidal cathodal current, which was applied epiretinally via a conical electrode. Spiking activity of targeted RGCs was recorded using a cell-attached patch electrode. MAIN RESULTS: ON and OFF cells had distinct responses to repetitive stimuli. Consistent with earlier studies, OFF cells always generated reduced responses to subsequent stimuli compared to responses to the first stimulus. In contrast, a new stimulus to ON cells suppressed all pending/ongoing responses from previous stimuli and initiated its own response that was remarkably similar to the response from a single stimulus in isolation. This previously unreported 'reset' behavior was observed exclusively and consistently in ON cells. These contrasts between ON and OFF cells created a range of stimulation rates (4-7 Hz) that maximized the ratio of the responses arising in ON versus OFF cells. SIGNIFICANCE: Previous clinical testing reported that subjects perceive bright phosphenes (ON responses) and also prefer stimulation rates of 5-7 Hz. Our results suggest that responses of ON cells are weak at high rates of stimulation (> ∼7 Hz) due to the reset while responses of OFF cells are strong at low rates (< ∼4 Hz) due to reduced desensitization, both reducing the ratio of ON to OFF responses. In combination with previous results indicating that responses in ON cells more closely match physiological patterns (Im and Fried 2015 J. Physiol. 593 3577-96), our results offer a potential reason for the user preference of intermediate rates (5-7 Hz).

Park-Windhol C, D’Amore P. Disorders of Vascular Permeability.. Annu Rev Pathol. 2016;11:251–81.

The endothelial barrier maintains vascular and tissue homeostasis and modulates many physiological processes, such as angiogenesis. Vascular barrier integrity can be disrupted by a variety of soluble permeability factors, and changes in barrier function can exacerbate tissue damage during disease progression. Understanding endothelial barrier function is critical for vascular homeostasis. Many of the signaling pathways promoting vascular permeability can also be triggered during disease, resulting in prolonged or uncontrolled vascular leak. It is believed that recovery of the normal vasculature requires diminishing this hyperpermeable state. Although the molecular mechanisms governing vascular leak have been studied over the last few decades, recent advances have identified new therapeutic targets that have begun to show preclinical and clinical promise. These approaches have been successfully applied to an increasing number of disease conditions. New perspectives regarding how vascular leak impacts the progression of various diseases are highlighted in this review.