PURPOSE: Subretinal (SR) injection in porcine models is a promising avenue for preclinical evaluation of cell and gene therapies. Targeting of the subretinal fluid compartment (bleb) is critical to the procedure, especially if treatment of the cone-rich area centralis is required (i.e., visual streak [VS] in pigs). To our knowledge, this study is the first to investigate the influence of injection site placement on VS involvement in the pig eye. METHODS: We performed 23-gauge pars plana vitrectomy followed by SR injection in 41 eyes of 21 animals (Sus scrofa domesticus). In 27 eyes (65.9%), the injection site was placed superior to the VS, and in 14 eyes (34.1%) it was placed inferior to it. Using intraoperative imaging, blebs were classified based on their propagation behavior relative to the VS. RESULTS: In 79% of cases, blebs from inferior injection sites developed away from the VS, exhibiting a mean ± SEM vertical anisotropy (AP) of 0.67 ± 0.11. In contrast, blebs from superior injection sites tended to develop toward the VS with an AP of 1.27 ± 0.18 (P = 0.0070). Blebs developed away from the VS in only 41% of injections (P = 0.0212). Inferior blebs were orientated close to 0° (horizontal), whereas superior blebs displayed varied orientations with a mean angle of 56° (P = 0.0008). CONCLUSIONS: Bleb propagation was anisotropic (i.e., directionally biased) and dependent on injection site placement. Superior injection sites led to superior VS detachment. Morphological analysis suggested increased adhesion forces at the VS and superior vascular arcades. This study will aid the planning of surgeries for targeted subretinal delivery in pig models.

Center for Innovative Medical Models Ludwig Maximilians Universität München München Bayern Germany

Institute of Animal Physiology and Genetics Akademie věd České republiky Praha Czechia

Medical Department 1 Cardiology Angiology Pneumology Klinikum rechts der Isar Technische Universität München München Bayern Germany

Nuffield Department of Clinical Neurosciences University of Oxford The John Radcliffe Hospital Oxford United Kingdom

Oxford University Hospitals NHS Foundation Trust Oxford Eye Hospital Oxford Oxfordshire United Kingdom

University Eye Hospital Eberhard Karls Universität Tübingen Tübingen Baden Württemberg Germany

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Sanchez I, Martin R, Ussa F, Fernandez-Bueno I.. The parameters of the porcine eyeball. Graefes Arch Clin Exp Ophthalmol. 2011; 249(4): 475–482. PubMed

Barone F, Nannoni E, Elmi A, et al. .. Behavioral assessment of vision in pigs. J Am Assoc Lab Anim Sci. 2018; 57(4): 350–356. PubMed PMC

Volland S, Esteve-Rudd J, Hoo J, Yee C, Williams DS. A comparison of some organizational characteristics of the mouse central retina and the human macula. PLoS One. 2015; 10(4): e0125631. PubMed PMC

Grotz S, Schäfer J, Wunderlich KA, et al. .. Early disruption of photoreceptor cell architecture and loss of vision in a humanized pig model of usher syndromes. EMBO Mol Med. 2022; 14(4): e14817. PubMed PMC

Scott PA, Fernandez de Castro JP, Kaplan HJ, McCall MA.. A Pro23His mutation alters prenatal rod photoreceptor morphology in a transgenic swine model of retinitis pigmentosa. Invest Ophthalmol Vis Sci. 2014; 55(4): 2452–2459. PubMed PMC

Vallender EJ, Hotchkiss CE, Lewis AD, et al. .. Nonhuman primate genetic models for the study of rare diseases. Orphanet J Rare Dis. 2023; 18(1): 20. PubMed PMC

Duarri A, Rodríguez-Bocanegra E, Martínez-Navarrete G, et al. .. Transplantation of human induced pluripotent stem cell-derived retinal pigment epithelium in a swine model of geographic atrophy. Int J Mol Sci. 2021; 22(19): 10497. PubMed PMC

Yang K, Jin X, Wang Z, et al. .. Robot-assisted subretinal injection system: development and preliminary verification. BMC Ophthalmol. 2022; 22(1): 484. PubMed PMC

Maierhofer NA, Jablonka AM, Roodaki H, et al. .. iOCT-guided simulated subretinal injections: a comparison between manual and robot-assisted techniques in an ex-vivo porcine model. J Robot Surg. 2023; 17(6): 2735–2742. PubMed PMC

Bennett J. Immune response following intraocular delivery of recombinant viral vectors. Gene Ther. 2003; 10(11): 977–982. PubMed

Bucher K, Rodríguez-Bocanegra E, Dauletbekov D, Fischer MD.. Immune responses to retinal gene therapy using adeno-associated viral vectors - Implications for treatment success and safety. Prog Retin Eye Res. 2021; 83: 100915. PubMed

Seitz IP, Michalakis S, Wilhelm B, et al. .. Superior retinal gene transfer and biodistribution profile of subretinal versus intravitreal delivery of AAV8 in nonhuman primates. Invest Ophthalmol Vis Sci. 2017; 58(13): 5792–5801. PubMed

Sisk RA, Berger TA, Williams ER, Riemann CD. Intraoperative bleb behavior in subretinal gene augmentation therapy for inherited retinal diseases. Retina. 2023; 43(10): 1763–1772. PubMed

Ducloyer JB, Pichard V, Mevel M, et al. .. Intravitreal air tamponade after AAV2 subretinal injection modifies retinal EGFP distribution. Mol Ther Methods Clin Dev. 2023; 28: 387–393. PubMed PMC