Inhibition of neovascularization but not fibrosis with the fluocinolone acetonide implant in autosomal dominant neovascular inflammatory vitreoretinopathy

Ultrawidefield Fluorescein Angiography and OCT Findings in Children and Young Adults with Autosomal Dominant Neovascular Inflammatory Vitreoretinopathy

PURPOSE

Autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV) is a rare genetic (CAPN5) autoimmune condition typically diagnosed in adulthood and characterized by a triad of inflammation, retinal degeneration, and neovascularization. We report novel multimodal imaging findings in children and young adults with ADNIV, and early treatment response to short-duration local and systemic corticosteroids.

DESIGN

Retrospective consecutive case series.

PARTICIPANTS

Ten patients aged <25 years with ADNIV and available multimodal imaging.

METHODS

The medical records of patients aged <25 years with a diagnosis of ADNIV with ultrawidefield fluorescein angiography (UWFFA) and OCT data were reviewed.

MAIN OUTCOME MEASURES

Ultrawidefield fluorescein angiography and OCT findings at baseline and after local corticosteroids.

RESULTS

Median age at presentation was 14 years (range, 9-24 years). OCT on presentation demonstrated cystoid macular edema in 8 of 20 eyes and symptomatic vitreoretinal interface disease in 2 of 20 eyes. Initial UWFFA demonstrated retinal vascular leakage (20/20 eyes, 100%), peripheral nonperfusion (13/20 eyes, 65%), and retinal neovascularization (6/20 eyes, 30%). Retinal vascular leakage improved with local corticosteroids, and neovascularization regressed with anti-VEGF therapy.

CONCLUSIONS

Ultrawidefield fluorescein angiography findings of prefibrotic ADNIV reported in adults were also present in children and young adults. Early testing for a pathogenic CAPN5 variant in at-risk children and regularly scheduled screening for uveitis and retinal vasculitis with UWFFA and OCT may prompt earlier intervention. Short-duration local steroids are effective at treating retinal vascular leakage and macular edema but are not durable, suggesting a potential role for steroid-sparing immunosuppressive therapy. Early treatment may alter the natural history of disease.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Early-onset Neovascular Inflammatory Vitreoretinopathy Due to Two de Novo CAPN5 Mutations in Chinese Patients: A Case Series

PURPOSE

To explore the clinical and molecular characteristics, diagnosis, and treatment of early-onset autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV) in Chinese patients.

METHODS

A retrospective, interventional case series was assembled from three ADNIV patients.

RESULTS

The three ADNIV cases harbored de novo CAPN5 mutations (p.Arg289Trp and p.Leu73Val). The ages of onset ranged from 11 months to 2 years. All the cases presented with vitreous opacity and subretinal inflammatory exudations. During the postoperative follow-up, all the patients manifested with exaggerated postoperative inflammatory responses. An intravitreal Ozurdex injection could not effectively control ocular inflammation in ADNIV. Laser spots after panretinal photocoagulation were partly visible.

CONCLUSIONS

Two de novo CAPN5 mutations (p.Leu73Val and p.Arg289Trp) could cause early-onset ADNIV. Panretinal photocoagulation during vitrectomy and an intravitreal Ozurdex injection could not significantly stop the progression of subretinal exudations and ocular inflammation in early-onset ADNIV patients.

Impaired activity and membrane association of most calpain-5 mutants causal for neovascular inflammatory vitreoretinopathy

Neovascular inflammatory vitreoretinopathy (NIV) is a rare eye disease that ultimately leads to complete blindness and is caused by mutations in the gene encoding calpain-5 (CAPN5), with six pathogenic mutations identified. In transfected SH-SY5Y cells, five of the mutations resulted in decreased membrane association, diminished S-acylation, and reduced calcium-induced autoproteolysis of CAPN5. CAPN5 proteolysis of the autoimmune regulator AIRE was impacted by several NIV mutations. R243, L244, K250 and the adjacent V249 are on β-strands in the protease core 2 domain. Conformational changes induced by Ca2+binding result in these β-strands forming a β-sheet and a hydrophobic pocket which docks W286 side chain away from the catalytic cleft, enabling calpain activation based on comparison with the Ca2+-bound CAPN1 protease core. The pathologic variants R243L, L244P, K250N, and R289W are predicted to disrupt the β-strands, β-sheet, and hydrophobic pocket, impairing calpain activation. The mechanism by which these variants impair membrane association is unclear. G376S impacts a conserved residue in the CBSW domain and is predicted to disrupt a loop containing acidic residues which may contribute to membrane binding. G267S did not impair membrane association and resulted in a slight but significant increase in autoproteolytic and proteolytic activity. However, G267S is also identified in individuals without NIV. Combined with the autosomal dominant pattern of NIV inheritance and evidence that CAPN5 may dimerize, the results are consistent with a dominant negative mechanism for the five pathogenic variants which resulted in impaired CAPN5 activity and membrane association and a gain-of-function for the G267S variant.

Long-Term Outcomes and Risk Factors for Severe Vision Loss in Autosomal Dominant Neovascular Inflammatory Vitreoretinopathy (ADNIV)

Autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV) is a rare disorder characterized by uveitis, retinal neovascularization, and retinal degeneration. We sought to describe the course of treated and untreated ADNIV and to identify risk factors for severe vision loss.

DESIGN

Observational case series.

METHODS

Clinical data from ADNIV patients from 4 families seen from 1967 through 2019 at a single academic, tertiary referral center were reviewed. The main outcome measures were visual acuity at baseline and follow-up, as well as risk factors for vision loss.

RESULTS

A total of 130 eyes from 65 ADNIV patients (45 female, 20 male; mean age 40.8 years, range 6-77 years) were included. Mean best corrected visual acuity (BCVA) at presentation was LogMAR 0.59 (about Snellen 20/80). Longitudinal analysis included 84 eyes from 42 patients (31 female, 11 male), with mean follow-up of 17.3 years (range 2-43.6 years). Mean BCVA at last follow-up was LogMAR 1.48 (about Snellen 20/600). The disease accelerated in the fifth decade of life, during which the majority of eyes went from normal vision or mild vision loss to at least moderate vision loss (20/70 Snellen equivalent); 25 eyes from 16 patients (29.8%;) showed a steep trajectory of vision loss to no light perception. Tractional retinal detachment was the greatest risk factor for severe vision loss (BCVA <20/200) on multivariable analysis (P < .05).

CONCLUSIONS

Patients with ADNIV have a high lifetime risk of severe vision loss. Tractional retinal detachment is an important risk factor for poor vision.

PROGRESSION OF SCOTOPIC SINGLE-FLASH ELECTRORETINOGRAPHY IN THE STAGES OF CAPN5 VITREORETINOPATHY

PURPOSE

To characterize the changes found in the electroretinography (ERG) recordings of patients with autosomal dominant neovascular inflammatory vitreoretinopathy and correlate with clinical stages of the disease.

METHODS

Retrospective chart review. Bright- and dim-flash full-field scotopic, photopic, and 30-Hz flicker ERGs were obtained according to international standards. The scotopic ERGs were further processed to analyze the oscillatory potential. The patient described in the case report underwent full ERG testing; five patients composed the archival case series data and included scotopic ERG recordings.

RESULTS

Stage I autosomal dominant neovascular inflammatory vitreoretinopathy is characterized by a decrease in the b-wave amplitude on scotopic flash ERG and the disappearance of late OPs; however, the a-wave amplitude is normal. In Stage II, attenuation of early OPs and the c-wave are observed in scotopic ERG recordings, but both a- and b-wave amplitudes are unchanged. For patients in Stage III, there is a continued decline of both a- and b-wave amplitudes in scotopic ERG recordings. There was a loss of recordable scotopic ERG response in patients with Stage IV disease.

CONCLUSION

Electroretinography may be valuable in determining optimal timing for therapeutic intervention and response before loss of recordable retinal function in CAPN5 vitreoretinopathy.

Therapeutic drug repositioning using personalized proteomics of liquid biopsies

BACKGROUND

In patients with limited response to conventional therapeutics, repositioning of already approved drugs can bring new, more effective options. Current drug repositioning methods, however, frequently rely on retrospective computational analyses and genetic testing - time consuming methods that delay application of repositioned drugs. Here, we show how proteomic analysis of liquid biopsies successfully guided treatment of neovascular inflammatory vitreoretinopathy (NIV), an inherited autoinflammatory disease with otherwise poor clinical outcomes.

METHODS

Vitreous biopsies from NIV patients were profiled by an antibody array for expression of 200 cytokine-signaling proteins. Non-NIV controls were compared with NIV samples from various stages of disease progression. Patterns were identified by 1-way ANOVA, hierarchical clustering, and pathway analysis. Subjects treated with repositioned therapies were followed longitudinally.

RESULTS

Proteomic profiles revealed molecular pathways in NIV pathologies and implicated superior and inferior targets for therapy. Anti-VEGF injections resolved vitreous hemorrhages without the need for vitrectomy surgery. Methotrexate injections reversed inflammatory cell reactions without the side effects of corticosteroids. Anti-IL-6 therapy prevented recurrent fibrosis and retinal detachment where all prior antiinflammatory interventions had failed. The cytokine array also showed that TNF-α levels were normal and that corticosteroid-sensitive pathways were absent in fibrotic NIV, helping explain prior failure of these conventional therapeutic approaches.

CONCLUSIONS

Personalized proteomics can uncover highly personalized therapies for autoinflammatory disease that can be timed with specific pathologic activities. This precision medicine strategy can also help prevent delivery of ineffective drugs. Importantly, proteomic profiling of liquid biopsies offers an endpoint analysis that can directly guide treatment using available drugs.

Two Novel CAPN5 Variants Associated with Mild and Severe Autosomal Dominant Neovascular Inflammatory Vitreoretinopathy Phenotypes

Purpose: We report two new CAPN5 mutations associated with a phenotype of Autosomal Dominant Neovascular Inflammatory Vitreoretinopathy. Methods: We performed next generation sequencing in two patients with ADNIV phenotype; the variants identified were explored further. Results: Patient 1 was heterozygous for CAPN5 c.799G>A, p.(Gly267Ser). Patient 2 was heterozygous for CAPN5 c.1126G>A, p.(Gly376Ser). Both amino acids are highly conserved across species. Patient 1 had a severe phenotype and his mutation lies within the protein's catalytic domain. Patient 2 had a mild phenotype and her mutation is the first ADNIV-causing mutation to be described in the regulatory domain of Calpain-5. Conclusions: Our findings potentially add two new ADNIV-causing CAPN5 mutations to the three previously described. We recommend CAPN5 genetic testing in all patients with a possible ADNIV phenotype, to develop our understanding of Calpain-5; a protein which could potentially provide therapeutically accessible targets for the treatment of many leading causes of blindness.

Secondary glaucoma in CAPN5-associated neovascular inflammatory vitreoretinopathy

Objective

The objective of this study was to review the treatment outcomes of patients with secondary glaucoma in cases of autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV), a hereditary autoimmune uveitis due to mutations in CAPN5.

Patients and methods

A retrospective, observational case series was assembled from ADNIV patients with secondary glaucoma. The main outcome measures were intraocular pressure (IOP), visual acuity, use of antiglaucoma medications, ocular surgeries, and adverse outcomes. Perimetry and optic disk optical coherence tomography (OCT) were also analyzed.

Results

Nine eyes of five ADNIV patients with secondary glaucoma were reviewed. Each received a fluocinolone acetonide (FA) implant for the management of posterior uveitis. Following implantation, no eyes developed neovascular glaucoma. Five eyes (in patients 1, 2, and 5) required Ahmed glaucoma valve surgery for the management of steroid-responsive glaucoma. Patient 2 also developed angle closure with iris bombe and underwent laser peripheral iridotomy. Patient 4 had both hypotony and elevated IOP that required periodic antiglaucoma medication in the FA-implanted eye. Patient 3 did not develop steroid-response glaucoma in either eye. Optic disk examinations were obscured by fibrosis and better assessed with OCT.

Conclusion

ADNIV patients show combined mechanism secondary glaucoma best assessed by OCT of the optic disk. The FA implants have reduced uveitic and neovascular glaucoma. Nevertheless, IOP management remains complex due to steroid-response glaucoma, angle closure glaucoma, and hypotony.

CAPN5 mutation in hereditary uveitis: the R243L mutation increases calpain catalytic activity and triggers intraocular inflammation in a mouse model

A single amino acid mutation near the active site of the CAPN5 protease was linked to the inherited blinding disorder, autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV, OMIM #193235). In homology modeling with other calpains, this R243L CAPN5 mutation was situated in a mobile loop that gates substrate access to the calcium-regulated active site. In in vitro activity assays, the mutation increased calpain protease activity and made it far more active at low concentrations of calcium. To test whether the disease allele could yield an animal model of ADNIV, we created transgenic mice expressing human (h) CAPN5(R243L) only in the retina. The resulting hCAPN5(R243L) transgenic mice developed a phenotype consistent with human uveitis and ADNIV, at the clinical, histological and molecular levels. The fundus of hCAPN5(R243L) mice showed enhanced autofluorescence (AF) and pigment changes indicative of reactive retinal pigment epithelial cells and photoreceptor degeneration. Electroretinography showed mutant mouse eyes had a selective loss of the b-wave indicating an inner-retina signaling defect. Histological analysis of mutant mouse eyes showed protein extravasation from dilated vessels into the anterior chamber and vitreous, vitreous inflammation, vitreous and retinal fibrosis and retinal degeneration. Analysis of gene expression changes in the hCAPN5(R243L) mouse retina showed upregulation of several markers, including members of the Toll-like receptor pathway, chemokines and cytokines, indicative of both an innate and adaptive immune response. Since many forms of uveitis share phenotypic characteristics of ADNIV, this mouse offers a model with therapeutic testing utility for ADNIV and uveitis patients.

Structural modeling of a novel CAPN5 mutation that causes uveitis and neovascular retinal detachment

CAPN5 mutations have been linked to autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV), a blinding autoimmune eye disease. Here, we link a new CAPN5 mutation to ADNIV and model the three-dimensional structure of the resulting mutant protein. In our study, a kindred with inflammatory vitreoretinopathy was evaluated by clinical eye examinations, DNA sequencing, and protein structural modeling to investigate the disease-causing mutation. Two daughters of an affected mother demonstrated symptoms of stage III ADNIV, with posterior uveitis, cystoid macular edema, intraocular fibrosis, retinal neovascularization, retinal degeneration, and cataract. The women also harbored a novel guanine to thymine (c.750G>T, p.Lys250Asn) missense mutation in exon 6 of CAPN5, a gene that encodes a calcium-activated cysteine protease, calpain-5. Modeling based on the structures of all known calpains revealed the mutation falls within a calcium-sensitive flexible gating loop that controls access to the catalytic groove. Three-dimensional modeling placed the new mutation in a region adjacent to two previously identified disease-causing mutations, all three of which likely disrupt hydrogen bonding within the gating loop, yielding a CAPN5 with altered enzymatic activity. This is the third case of a CAPN5 mutation leading to inherited uveitis and neovascular vitreoretinopathy, suggesting patients with ADNIV features should be tested for CAPN5 mutations. Structural modeling of novel variants can be used to support mechanistic consequences of the disease-causing variants.

Fibrotic encapsulation of a dexamethasone intravitreal implant following vitrectomy and silicone oil for rhegmatogenous retinal detachment

Steroids are commonly used as adjunct therapy in the management of proliferative vitreoretinopathy. The authors report a case of proliferative vitreoretinopathy treated with an intravitreal dexamethasone implant following vitrectomy in a silicone oil-filled eye. Epiretinal fibrosis developed around the implant at 6 weeks postoperatively, resulting in a recurrent retinal detachment. This was repaired by vitrectomy, removal of the implant, and peeling of epiretinal proliferation.

Functional validation of a human CAPN5 exome variant by lentiviral transduction into mouse retina

Exome sequencing indicated that the gene encoding the calpain-5 protease, CAPN5, is the likely cause of retinal degeneration and autoimmune uveitis in human patients with autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV, OMIM #193235). To explore the mechanism of ADNIV, a human CAPN5 disease allele was expressed in mouse retinas with a lentiviral vector created to express either the wild-type human (h) CAPN5 or the ADNIV mutant hCAPN5-R243L allele under a rhodopsin promoter with tandem green fluorescent protein (GFP) expression. Vectors were injected into the subretinal space of perinatal mice. Mouse phenotypes were analyzed using electroretinography, histology and inflammatory gene expression profiling. Mouse calpain-5 showed high homology to its human ortholog with >98% sequence identity that includes the ADNIV mutant residue. Calpain-5 protein was expressed in the inner and outer segments of the photoreceptors and in the outer plexiform layer. Expression of the hCAPN5-R243L allele caused loss of the electroretinogram b-wave, photoreceptor degeneration and induction of immune cell infiltration and inflammatory genes in the retina, recapitulating major features of the ADNIV phenotype. Intraocular neovascularization and fibrosis were not observed during the study period. Our study shows that expression of the hCAPN5-R243L disease allele elicits an ADNIV-like disease in mice. It further suggests that ADNIV is due to CAPN5 gain-of-function rather than haploinsufficiency, and retinal expression may be sufficient to generate an autoimmune response. Genetic models of ADNIV in the mouse can be used to explore protease mechanisms in retinal degeneration and inflammation as well as preclinical therapeutic testing.

Translational vitreous proteomics

The vitreous is an extracellular matrix that is still poorly understood. Although many constituents and characteristics have been previously determined, there are many attributes still being discovered. Currently, using protein arrays, MS, and bioinformatics, the vitreous provides a wealth of knowledge regarding ocular diseases and potential targets for personalized therapeutics.

Lymphocyte infiltration in CAPN5 autosomal dominant neovascular inflammatory vitreoretinopathy

PURPOSE

To describe immunohistopathological findings in autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV).

METHODS

An enucleated eye specimen from a patient with Stage V ADNIV was examined using standard histopathological methods and lymphocyte markers.

RESULTS

A c.731T>C CAPN5 mutation resulted in a p.Leu244Pro substitution in calpain-5. The eye showed exudative retinal detachment and neovascularization, intraocular fibrosis, and features of phthisis bulbi. Chronic inflammatory CD3-positive cell infiltrates were identified throughout the uvea, vitreous and retina, consistent with chronic uveitis.

CONCLUSION

Mutations in CAPN5 trigger autoimmune uveitis characterized by inflammatory T-cells and severe neovascularization.

Surgical management of fibrotic encapsulation of the fluocinolone acetonide implant in CAPN5-associated proliferative vitreoretinopathy

Objective

To review fibrosis of fluocinolone acetonide (FA) implants in subjects with CAPN5 autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV).

Methods

A retrospective case series was assembled from ADNIV patients in which there was fibrotic encapsulation of a fluocinolone acetonide implant. CAPN5 genotypes and surgical repair techniques were reviewed.

Results

Two eyes of two ADNIV patients developed a fibrotic capsule over the fluocinolone acetonide implant. Both patients had Stage IV disease. Patient A had a c.731T > C mutation in the CAPN5 gene and patient B had a c.728G > T mutation. The fibrotic membrane was surgically excised and the implant function was restored.

Conclusion

The exuberant fibrotic response in later stages of ADNIV may be resistant to local immunosuppression with steroids. Surgical excision of fibrotic membranes over FA implants can reestablish local steroid delivery in cases of severe proliferative vitreoretinopathy.

Monozygotic twins with CAPN5 autosomal dominant neovascular inflammatory vitreoretinopathy

BACKGROUND

The purpose of this study was to describe the clinical findings in a set of monozygotic twins with autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV) over a 23-year period.

METHODS

A pair of female twins were examined between 26 and 49 years of age. The concordance and discordance of their clinical features were determined. The CAPN5 gene was sequenced using genomic DNA.

RESULTS

Both twins of an affected father demonstrated Stage I ADNIV with mild vitreous cells and a negative b-wave on electroretinography. Genetic analysis confirmed a guanine to thymine nucleotide (c.728G>T, pArg243Leu) mutation in the CAPN5 gene. Over the course of 23 years, each twin progressed to stage III disease, showing posterior uveitis, cystoid macular edema, intraocular fibrosis, early retinal neovascularization, retinal degeneration, and cataract. Disease progression varied moderately between each twin and was asymmetrical between eyes. Twin A had 20/70 and 20/125 in the right and left eye, respectively, and underwent vitrectomy surgery and intravitreal injections with bevacizumab for recurrent cystoid macular edema. Twin B maintained 20/20 and 20/40 in the right and left eye, respectively without intervention.

CONCLUSION

There was asymmetry between the eyes and some discordance in the rate of disease progression in these monozygotic twins with ADNIV. The overall high disease concordance suggests genetic factors play a major role in clinical manifestations in CAPN5 vitreoretinopathy.