PYK-1105: Preclinical Evaluation of a Novel Biodegradable Vitreous Substitute for Retinal Tamponade.

Purpose: Current retinal tamponade strategies are limited by anatomic considerations (retinal break location), durability (short-term vs need for removal), and patient adherence (positioning, travel/altitude restrictions). Here we describe the preclinical safety and toxicology of a novel biodegradable hydrogel tamponade agent (PYK-1105) with the potential to improve both patient experience and outcomes after retina surgery. Methods: We studied in vitro performance to assess hydrogel gelation time, modulus, viscosity, degradation time, refractive index, and transmittance. In addition to studying in vitro and in vivo (mice and rabbits) biocompatibility, testing was performed to assess cytotoxicity, intraocular irritation, acute systemic toxicity, genotoxicity, and pyrogenicity. Furthermore, clinical safety was assessed using in vivo (rabbits and minipigs) response to vitrectomy with PYK-1105 insertion with the following measures: clinical examination, multimodal imaging, full-field electroretinography, and histopathology. Results: PYK-1105 met the predefined performance testing criteria for optimal tamponade and demonstrated excellent biocompatibility. Animal studies showed the PYK-1105 formulation to be well tolerated and nontoxic in mice, rabbits, and pigs. Conclusions: PYK-1105 holds promise as a new biodegradable tamponade agent that has the potential to improve both the patient experience and outcomes after retina surgery. Human pilot studies are warranted to further assess for safety and efficacy.

Impact of contact versus non-contact wide-angle viewing systems on outcomes of primary retinal detachment repair (PRO study report number 5).

BACKGROUND/AIMS: Vitrectomy to repair retinal detachment is often performed with either non-contact wide-angle viewing systems or wide-angle contact viewing systems. The purpose of this study is to assess whether the viewing system used is associated with any differences in surgical outcomes of vitrectomy for primary non-complex retinal detachment repair. METHODS: This is a multicenter, interventional, retrospective, comparative study. Eyes that underwent non-complex primary retinal detachment repair by either pars plana vitrectomy (PPV) alone or in combination with scleral buckle/PPV in 2015 were evaluated. The viewing system at the time of the retinal detachment repair was identified and preoperative patient characteristics, intraoperative findings and postoperative outcomes were recorded. RESULTS: A total of 2256 eyes were included in our analysis. Of those, 1893 surgeries used a non-contact viewing system, while 363 used a contact lens system. There was no statistically significant difference in single surgery anatomic success at 3 months (p=0.72), or final anatomic success (p=0.40). Average postoperative visual acuity for the contact-based cases was logMAR 0.345 (20/44 Snellen equivalent) compared with 0.475 (20/60 Snellen equivalent) for non-contact (p=0.001). After controlling for numerous confounding variables in multivariable analysis, viewing system choice was no longer statistically significant (p=0.097). CONCLUSION: There was no statistically significant difference in anatomic success achieved for primary retinal detachment repair when comparing non-contact viewing systems to contact lens systems. Postoperative visual acuity was better in the contact-based group but this was not statistically significant when confounding factors were controlled for.

FACTORS ASSOCIATED WITH THE USE OF 360-DEGREE LASER RETINOPEXY DURING PRIMARY VITRECTOMY WITH OR WITHOUT SCLERAL BUCKLE FOR RHEGMATOGENOUS RETINAL DETACHMENT AND IMPACT ON SURGICAL OUTCOMES (PRO STUDY REPORT NUMBER 4).

PURPOSE: To determine factors associated with 360-degree laser retinopexy (360LR) during primary pars plana vitrectomy ± scleral buckle for rhegmatogenous retinal detachment (RRD) and its impact on surgical outcomes. METHODS: This is a multicenter, retrospective, interventional study. Patients undergoing primary pars plana vitrectomy or primary pars plana vitrectomy + scleral buckle for noncomplex primary RRD in 2015 were evaluated. Primary outcomes were single surgery anatomical success (SSAS) and final anatomical success. Secondary outcomes included final logarithm of the minimum angle of resolution visual acuity, epiretinal membrane formation, cystoid macular edema development, and number of subsequent vitrectomies. Multivariate regressions were performed. RESULTS: Two thousand two hundred and forty-eight surgeries by 61 surgeons were included; of which, 516 underwent 360LR. Younger age (P = 0.01), more retinal breaks (P = 0.01), more extensive RRD (P < 0.001), and surgeon ID (P < 0.001) were significantly associated with 360LR. No significant associations between 360LR and single surgery anatomical success (P = 0.44), epiretinal membrane formation (P = 0.14), cystoid macular edema development (P = 0.28), or number of subsequent vitrectomies (P = 0.41) were found. Controlling for case complexity, 360LR was significantly associated with lower final anatomical success (P < 0.001) and worse final logarithm of the minimum angle of resolution visual acuity (P < 0.001). CONCLUSION: Multiple factors influenced whether 360LR was performed during primary pars plana vitrectomy ± scleral buckle for RRD. However, 360LR was not associated with improved surgical outcomes, and in fact, it may be associated with poorer outcomes.

Effect of Methotrexate on an In Vitro Patient-Derived Model of Proliferative Vitreoretinopathy.

Purpose: The purpose of this study was to develop a method for isolating, culturing, and characterizing cells from patient-derived membranes in proliferative vitreoretinopathy (PVR) to be used for drug testing. Methods: PVR membranes were obtained from six patients with grade C PVR. Membrane fragments were analyzed by gross evaluation, fixed for immunohistologic studies to establish cell identity, or digested with collagenase II to obtain single cell suspensions for culture. PVR-derived primary cultures were used to examine the effects of methotrexate (MTX) on proliferation, migration, and cell death. Results: Gross analysis of PVR membranes showed presence of pigmented cells, indicative of retinal pigment epithelial cells. Immunohistochemistry identified cells expressing α-smooth muscle actin, glial fibrillary acidic protein, Bestrophin-1, and F4/80, suggesting the presence of multiple cell types in PVR. Robust PVR primary cultures (C-PVR) were successfully obtained from human membranes, and these cells retained the expression of cell identity markers in culture. C-PVR cultures formed membranes and band-like structures in culture reminiscent of the human condition. MTX significantly reduced the proliferation and band formation of C-PVR, whereas it had no significant effect on cell migration. MTX also induced regulated cell death within C-PVR as assessed by increased expression of caspase-3/7. Conclusions: PVR cells obtained from human membranes can be successfully isolated, cultured, and profiled in vitro. Using these primary cultures, we identified MTX as capable of significantly reducing growth and inducing cell death of PVR cells in vitro.

CHRONICALLY PROGRESSIVE SARCOID GRANULOMA IN AN ASYMPTOMATIC PATIENT.

PURPOSE: To report 18 years of follow-up of a patient with atypical ocular sarcoidosis. METHODS: The patient was observed in clinic and with photography for over 18 years. RESULTS: One patient with a history of dermal melanoma and atypical ocular sarcoidosis. DISCUSSION: Several features presented in this case are exceedingly atypical including lack of any intraocular inflammation over 18 years of yearly observation, the preservation of excellent vision despite the choroidal disease, and lack of systemic symptoms. This case suggests a disconnect between ocular sarcoidosis and intraocular inflammation, and supports clinical observation as a prudent method in patients with extensive choroidal disease and good vision.

Myeloid WNT7b mediates the angiogenic switch and metastasis in breast cancer.

Oncogenic targets acting in both tumor cells and tumor stromal cells may offer special therapeutic appeal. Interrogation of the Oncomine database revealed that 52 of 53 human breast carcinomas showed substantial upregulation of WNT family ligand WNT7B. Immunolabeling of human mammary carcinoma showed that WNT7B immunoreactivity was associated with both tumor cells and with tumor-associated macrophages. In the MMTV-PymT mouse model of mammary carcinoma, we found tumor progression relied upon WNT7B produced by myeloid cells in the microenvironment. Wnt7b deletion in myeloid cells reduced the mass and volume of tumors due to a failure in the angiogenic switch. In the tumor overall, there was no change in expression of Wnt/ß-catenin pathway target genes, but in vascular endothelial cells (VEC), expression of these genes was reduced, suggesting that VECs respond to Wnt/ß-catenin signaling. Mechanistic investigations revealed that failure of the angiogenic switch could be attributed to reduced Vegfa mRNA and protein expression in VECs, a source of VEGFA mRNA in the tumor that was limiting in the absence of myeloid WNT7B. We also noted a dramatic reduction in lung metastasis associated with decreased macrophage-mediated tumor cell invasion. Together, these results illustrated the critical role of myeloid WNT7B in tumor progression, acting at the levels of angiogenesis, invasion, and metastasis. We suggest that therapeutic suppression of WNT7B signaling might be advantageous due to targeting multiple aspects of tumor progression.

Macrophage Wnt-Calcineurin-Flt1 signaling regulates mouse wound angiogenesis and repair.

The treatment of festering wounds is one of the most important aspects of medical care. Macrophages are important components of wound repair, both in fending off infection and in coordinating tissue repair. Here we show that macrophages use a Wnt-Calcineurin-Flt1 signaling pathway to suppress wound vasculature and delay repair. Conditional mutants deficient in both Wntless/GPR177, the secretory transporter of Wnt ligands, and CNB1, the essential component of the nuclear factor of activated T cells dephosporylation complex, displayed enhanced angiogenesis and accelerated repair. Furthermore, in myeloid-like cells, we show that noncanonical Wnt activates Flt1, a naturally occurring inhibitor of vascular endothelial growth factor-A-mediated angiogenesis, but only when calcineurin function is intact. Then, as expected, conditional deletion of Flt1 in macrophages resulted in enhanced wound angiogenesis and repair. These results are consistent with the published link between enhanced angiogenesis and enhanced repair, and establish novel therapeutic approaches for treatment of wounds.

Metchnikoff's policemen: macrophages in development, homeostasis and regeneration.

Over the past decade, modern genetic tools have permitted scientists to study the function of myeloid lineage cells, including macrophages, as never before. Macrophages were first detected more than a century ago as cells that ingested bacteria and other microbes, but it is now known that their functional roles are far more numerous. In this review, we focus on the prevailing functions of macrophages beyond their role in innate immunity. We highlight examples of macrophages acting as regulators of development, tissue homoeostasis, remodeling (the reorganization or renovation of existing tissues) and repair. We also detail how modern genetic tools have facilitated new insights into these mysterious cells.

Regulation of angiogenesis by a non-canonical Wnt-Flt1 pathway in myeloid cells.

Myeloid cells are a feature of most tissues. Here we show that during development, retinal myeloid cells (RMCs) produce Wnt ligands to regulate blood vessel branching. In the mouse retina, where angiogenesis occurs postnatally, somatic deletion in RMCs of the Wnt ligand transporter Wntless results in increased angiogenesis in the deeper layers. We also show that mutation of Wnt5a and Wnt11 results in increased angiogenesis and that these ligands elicit RMC responses via a non-canonical Wnt pathway. Using cultured myeloid-like cells and RMC somatic deletion of Flt1, we show that an effector of Wnt-dependent suppression of angiogenesis by RMCs is Flt1, a naturally occurring inhibitor of vascular endothelial growth factor (VEGF). These findings indicate that resident myeloid cells can use a non-canonical, Wnt-Flt1 pathway to suppress angiogenic branching.