Porcine models of choroidal neovascularization: A systematic review.

Animal models of choroidal neovascularization (CNV) are extensively used in translational studies of CNV formation and to evaluate angiostatic treatment strategies. However, the current paucity of large animal models compared with rodent models constitutes a knowledge gap regarding the clinical translation of findings. Ocular anatomical and physiological similarities to humans suggest the pig as a relevant model animal. Thus, a systematic survey of porcine CNV models was performed to identify pertinent model parameters and suggest avenues for model standardization and optimization. A systematic search was performed in PubMed and EMBASE on November 28, 2022 for porcine models of CNV. Following inclusion by two investigators, data from the articles were extracted according to a predefined protocol. A total of 14 articles, representing 19 independent porcine CNV models were included. The included models were almost equally divided between laser-induced (53%) and surgically-induced (47%) models. Different specified breeds of domestic pigs (71%) were most commonly used in the studies. All studies used normal animals. Female pigs were reported used in 43% of the studies, while 43% did not report on sex of the animals. Younger pigs were typically used. The surgical models reported consistent CNV induction following mechanical Bruch's membrane rupture. The laser models used variants of the infrared diode laser (40%) or the frequency-doubled Nd:YAG laser (50%). Both lasers enabled successful CNV induction with reported induction rates ranging from 60 to 100%. Collateral damage to the neuroretina was reported for the infrared diode laser. CNV evaluation varied across studies with fluorescein angiography (50%) as the most used in vivo method and retinal sections (71%) as the most used ex vivo method. In interventional studies, quantification of lesions was in general performed between 7 and 14 days. The field of porcine CNV models is relatively small and heterogeneous and almost equally divided between surgically-induced and laser-induced models. Both methods have allowed successful modeling of CNV formation with induction rates comparable to those of non-human primates. However, the field would benefit from standardization of model parameters and reporting. This includes laser parameters and validation of CNV formation as well as methods of CNV evaluation and statistical analysis.

Future Perspectives of Prime Editing for the Treatment of Inherited Retinal Diseases.

Inherited retinal diseases (IRD) are a clinically and genetically heterogenous group of diseases and a leading cause of blindness in the working-age population. Even though gene augmentation therapies have shown promising results, they are only feasible to treat a small number of autosomal recessive IRDs, because the size of the gene is limited by the vector used. DNA editing however could potentially correct errors regardless of the overall size of the gene and might also be used to correct dominant mutations. Prime editing is a novel CRISPR/Cas9 based gene editing tool that enables precise correction of point mutations, insertions, and deletions without causing double strand DNA breaks. Due to its versatility and precision this technology may be a potential treatment option for virtually all genetic causes of IRD. Since its initial description, the prime editing technology has been further improved, resulting in higher efficacy and a larger target scope. Additionally, progress has been achieved concerning the size-related delivery issue of the prime editor components. This review aims to give an overview of these recent advancements and discusses prime editing as a potential treatment for IRDs.

Animal Models of Choroidal Neovascularization: A Systematic Review.

Purpose: Animal models of choroidal neovascularization (CNV) are extensively used to characterize the pathophysiology of chorioretinal diseases with CNV formation and to evaluate novel treatment strategies. This systematic review aims to give a detailed overview of contemporary animal models of CNV. Methods: A systematic search was performed in PubMed and EMBASE from November 20, 2015, to November 20, 2020, for mammalian animal models of CNV. Following inclusion by two investigators, data from the articles were extracted according to a predefined protocol. Results: A total of 380 full articles, representing 409 independent animal models, were included. Mice were by far the most utilized animal (76%) followed by rats and non-human primates. The median age of rodents was 8 weeks but with a wide range. Male animals were used in 44% of the studies, but 32% did not report the sex. CNV was laser induced in 89% of the studies, but only 44% of these reported sufficiently on standard laser parameters. Surprisingly, 28% of the studies did not report a sample size for quantitative CNV evaluation. Less than half of the studies performed quantitative in vivo evaluation, and 73% evaluated CNV quantitatively ex vivo. Both in vivo and ex vivo evaluations were conducted primarily at day 7 and/or day 14. Conclusions: The laser-induced mouse model is the predominant model for experimental CNV. The widespread use of young, healthy male animals may complicate clinical translation, and inadequate reporting challenges reproducibility. Definition and implementation of standardized methodologic and reporting guidelines are attractive.

Subretinal Saline Protects the Neuroretina From Thermic Damage During Laser Induction of Experimental Choroidal Neovascularization in Pigs.

Purpose: The purpose of this study was to develop a porcine model for photocoagulation induced choroidal neovascularization (CNV) with high success rate and minimal thermic damage to the neuroretina. Methods: Experimental CNV was induced by laser photocoagulation in both eyes of 16 domestic pigs. In the left eyes, photocoagulation was preceded by subretinal injection of saline to protect the neuroretina from thermic damage, whereas the right eyes were treated with photocoagulation only. The development of the CNV after 3, 7, 14, 28, and 42 days was evaluated by optical coherence tomography (OCT) scanning, fluorescein angiography, and OCT angiography, and by histology after enucleation. Results: From day 7 after the photocoagulation, OCT showed subretinal density in all lesions of 14 alive animals, and either fluorescein or OCT angiography confirmed CNV formation in 11 of 14 of the eyes that had received photocoagulation alone and those in which photocoagulation had been preceded by subretinal injection of saline. In all cases pretreated with subretinal saline, the neuroretina was protected from immediate thermic damage. The formation of CNVs were confirmed by histology. For both groups, the largest lesions were observed within 14 days after photocoagulation. Conclusions: Injection of subretinal saline can protect the retina from thermic damage induced by retinal photocoagulation without reducing the success rate in producing experimental CNV. The effect of interventional studies aimed at reducing photocoagulation induced experimental CNV in pigs can be evaluated within 2 weeks after photocoagulation. Translational Relevance: This model provides a fundament to develop and evaluate novel treatment methods for neovascular retinal diseases.

Safety and efficacy of lesion preparation with the AngioSculpt Scoring Balloon in left main interventions: the ALSTER Left Main registry.

AIMS: Left main interventions require optimal initial results for good clinical outcome. Lesion preparation with the AngioSculpt Scoring Balloon (ASB) combined with the provisional T-stenting technique, if proven safe, might lead to better lumen gain and better clinical outcome. The aim of this registry was to investigate the safety and efficacy of the ASB as an option for lesion preparation in unprotected left main interventions (ULMI). METHODS AND RESULTS: Out of the all-comers unprotected left main registry (ULMI ALSTER), 47 patients with elective ULMI fulfilled the inclusion criteria for this study. The endpoints were acute lumen gain and 12-month MACCE. The drop-out rate was 4%. The provisional T-stenting technique was used in 97% of distal ULMI. The interventions were grouped according to use of ASB with an in-house, historical no-ASB patient control group. Lumen gain was 1.63±0.12 mm in the ASB group (n=34) and 1.35±0.12 mm in the no-ASB group (n=8, p=0.26), respectively. The use of the ASB was safe. Intravascular ultrasound (IVUS) data for 21 patients showed numerically greater lumen area gain of 3.14±0.33 mm2 in the ASB group compared to 2.33±0.88 mm2 with the conventional technique. TLR/TVR was 6.6% overall. Twelve-month MACCE was 12.5% (4/32) for ASB and 15.4% (2/13) in the historical control group. CONCLUSIONS: Adding ASB lesion preparation to the standard provisional T-stenting technique for ULMI is feasible and safe. Low TLR and TVR rates were observed. Lesion preparation led to a numerically larger lumen gain; the data allow valid power statistics to show this approach as leading to improved outcome in a possible randomised trial.

Effect of Urocortin on strength and microarchitecture of osteopenic rat femur.

As yet there is no evidence of the potential antiosteoporotic effect of Urocortin-1 (UCN), a corticotropin releasing factor related peptide, in vivo. In this study, and for the first time, we investigated the effect of UCN in a rat osteopenia model. Sixty female Sprague-Dawley rats were divided into 5 groups: (1) sham-operated, (2) untreated ovariectomized (OVX) rats, (3) and (4) OVX animals treated for 5 weeks with daily subcutaneous low-dose UCN (3 µg/kg of BW) or high-dose UCN (30 µg/kg of BW) 8 weeks after ovariectomy, and (5) OVX rats treated with daily estrogen (0.2 mg/kg of BW p.o) 8 weeks after ovariectomy for 5 weeks (E). After sacrifice, the femurs were reserved for biomechanical, histomorphometric and ash testing. In the biomechanical test, the high-dose UCN rats showed significantly improved mechanical stiffness (341.6 N/mm) compared with the untreated OVX animals (275.9 N/mm). In the histomorphometric evaluation, the high-dose UCN rats demonstrated an improved trabecular microarchitecture especially and significantly at the distal femur (distal femur Tb.Ar = 41.4% and N.Nd/mm(2) = 26.8, proximal femur Tb.Ar = 71.8% and N.Nd/mm(2) = 28.7) compared with untreated OVX rats (distal femur Tb.Ar = 23.3% and N.Nd/mm(2) = 11.7, proximal femur Tb.Ar = 60.2% and N.Nd/mm(2) = 25.2). Our results show that short-term treatment with UCN seems to have a positive effect on the metaphyseal bone structure and strength of the femur in ovariectomized rats.