Aqueous outflow system in familial amyloidotic polyneuropathy, Portuguese type

Silencing of ocular transthyretin, a gene responsible for hereditary transthyretin amyloidosis, by intravitreal injection of an siRNA conjugate into rabbit eyes

The first small interfering RNA (siRNA) therapeutic received approval for hereditary transthyretin (ATTRv) amyloidosis, and the patients' lifespan extension by specific inhibition of hepatic synthesis of transthyretin (TTR) is expected. However, ocular amyloidosis in these patients has been a crucial issue. This study aims to evaluate the efficacy and safety of intravitreal TTR siRNA conjugate injection into rabbit eyes. Rabbit (r) TTR siRNA is a screened TTR siRNA conjugate from 53 candidates. The intraocular pressure (IOP) immediately after injection was high despite the 65.9 % decrease of aqueous humor TTR protein levels in the rTTR siRNA group compared with those in the Control siRNA group 2 weeks after the 50 μL siRNA injection. The IOP spike was milder after the 30 μL siRNA injection, and aqueous humor TTR levels decreased by ∼50 % in the rTTR siRNA group, which is consistent with the mRNA levels in the retina. The parameters of dark-adapted, light-adapted, and light-adapted 30 Hz electroretinogram and the thickness of each retinal layer in histological analysis demonstrated no significant differences between the groups. In conclusion, we developed TTR siRNA conjugates for rabbit eyes, and the results indicate that intravitreal TTR siRNA conjugate injection could be a therapeutic option for ocular amyloidosis caused by ATTRv amyloidosis.

Suture trabeculotomy ab interno for secondary glaucoma in Japanese patients with Val30Met hereditary transthyretin amyloidosis

We retrospectively evaluated surgical outcomes of suture trabeculotomy (SLOT) ab interno for secondary glaucoma in 18 eyes of 12 patients with hereditary transthyretin (ATTRv) amyloidosis with Val30Met mutation. SLOT ab interno was performed between May 2015 and January 2020. All the participants were followed up for at least 12 months. The primary outcome measure was Kaplan-Meier survival. Failure of this treatment was defined as an intraocular pressure (IOP) of ≥ 22 mmHg and a < 20% IOP reduction with or without medication or as additional operations needed to reduce IOP. The mean postoperative follow-up period was 3.5 years (1.2-6.1 years). The SLOT ab interno procedure alone was performed in 17 eyes (94%). Fifteen eyes (83%) had a 360° incision made in Schlemm's canal and 3 eyes (17%) had a 180° incision performed. Cumulative survival values were 0.83, 0.63, and 0.22 at 1, 2, and 3 years, respectively. Ten eyes (56%) needed additional surgery, such as repeated SLOT ab interno, Ahmed glaucoma valve implantation, or MicroPulse transscleral cyclophotocoagulation. Our results here, as well as our previous results with trabeculectomy, suggest that SLOT ab interno may not have a sufficiently long-term effect on secondary glaucoma because of ATTRv amyloidosis.

Specific postoperative complications of vitrectomy in hereditary transthyretin amyloidosis

INTRODUCTION

Vitrectomy may improve visual acuity of hereditary transthyretin amyloidosis (ATTRv) patients presenting with vitreous opacities but is associated with severe complications. The objective of this study is to report visual outcomes, early and late complications of a series of ATTRv patients who underwent vitrectomy in the French ATTRv reference center.

METHODS

This retrospective, single-center study, included all ATTRv patients who underwent vitrectomy between 2002 and 2017. Data were collected on pre and postoperative best corrected visual acuity (BCVA) and early and late postoperative complications.

RESULTS

A total of 21 eyes from 15 patients were included. The mean postoperative follow-up was 40 ± 20 months (6-160 months). BCVA increased from 0.7 ± 0.4 LogMAR preoperatively to 0.3 ± 0.4 LogMAR (p = 0.003) at last postoperative visit. During follow-up, all initially glaucomatous eyes worsened, with three eyes (37%) requiring filtering surgery and two eyes (25%) had further vision loss. Among non-glaucomatous patients, four eyes (31%) developed glaucoma with two requiring trabeculectomy and one eye (8%) had further vision loss. Three eyes (three patients) presented with complications of amyloid angiopathy. Three eyes (three patients) experienced recurrence of vitreous deposits requiring surgical revision.

CONCLUSION

Due to the potential complications, vitrectomy in ATTRv requires specific perioperative management and life-long postoperative monitoring.

Anterior Chamber Flare as an Objective and Quantitative Noninvasive Method for Oculopathy in Transthyretin V30M Amyloidosis Patients

Purpose

Assess the aqueous humor flare in transthyretin V30M amyloidosis patients (ATTRV30M).

Materials and Methods

This is a retrospective, cross-sectional, noninterventional comparative study including 28 ATTRV30M patients with a unilateral scalloped iris. For comparative analysis, the fellow eye, the nonscalloped iris eye, from each patient was used as control. All patients underwent aqueous humor flare meter and intraocular pressure (IOP) measurements.

Results

Mean aqueous humor flare was significantly higher in the eyes with the scalloped iris than the control group with the nonscalloped iris (14.1 ± 2.2 versus 6.5 ± 0.9 pc/ms, respectively). No significant differences in IOP were found in the scalloped iris eyes than those in the nonscalloped iris control group (17.1 ± 0.8 versus 16.8 ± 0.7 mmHg, respectively). No significant correlation was not found between the flare and the IOP value within groups.

Conclusions

In this study, aqueous humor flare values in the scalloped iris eyes may be a valid marker for controlling the stage of the oculopathy in ATTRV30M patients.

Nonpenetrating deep sclerectomy as an effective treatment of glaucoma related to familial amyloid polyneuropathy

PURPOSE

To present the clinical course and treatment by nonpenetrating deep sclerectomy (NPDS) of open-angle glaucoma secondary to familial amyloid polyneuropathy (FAP).

PATIENTS AND METHODS

In a series of 10 patients with FAP in a tertiary ophthalmology center, 4 eyes of 3 patients required glaucoma filtration surgery and NPDS with implant, and local intraoperative mitomycin C application was performed. Intraocular pressure and anatomic bleb functionality were measured. We performed a retrospective review of data from medical charts of the 10 FAP patients, which included demographics, incidence and treatment of glaucoma, and previous vitrectomy.

RESULTS

NPDS resulted in normalization of intraocular pressure in all 4 eyes. Ten eyes (6 patients) of the studied group underwent vitrectomy because of amyloid opacities, 7 eyes (4 patients) had glaucoma, 6 of the eyes with glaucoma were previously vitrectomized, and 4 of them subsequently required glaucoma surgery.

CONCLUSIONS

NPDS is an effective treatment of FAP glaucoma. Previously vitrectomized eyes have a more severe course of glaucoma and more frequently require filtration surgery.

Long-term outcomes and complications of trabeculectomy for secondary glaucoma in patients with familial amyloidotic polyneuropathy

Objective

Secondary glaucoma is a serious complication in patients with transthyretin (TTR)-related familial amyloidotic polyneuropathy (FAP). We assessed the long-term outcomes and complications of trabeculectomy with mitomycin C (MMC) for secondary glaucoma associated with FAP.

Methods

Medical case records of Kumamoto University Hospital were retrospectively reviewed. Twenty-one eyes of 13 patients (10 with FAP ATTR Val30Met; 3 with FAP ATTR Tyr114Cys) underwent trabeculectomy with MMC and follow-up of at least 2 years. The primary outcome measure was Kaplan-Meier survival, with failure of this treatment being defined as an intraocular pressure (IOP) of ≤5 mm Hg or ≥22 mm Hg on two consecutive visits or as additional operations needed to reduce IOP. Secondary outcome measures included complications, bleb characteristics, and additional postoperative interventions required.

Results

The mean postoperative follow-up period was 5.7 years (range, 2.2–12.7 years). Kaplan-Meier analysis indicated probabilities of success of 0.76, 0.67, and 0.53 at 1, 2, and 3 years after operation, respectively. Significant complications included ocular decompression retinopathy in 7 eyes (33%) and bleb encapsulation in 10 eyes (48%). Twelve eyes (57%) needed additional surgery, such as bleb revision or trabeculectomy with MMC, to reduce IOP.

Conclusions

Trabeculectomy with MMC may not be optimal for patients with FAP-related glaucoma and may have several significant complications.

Ophthalmic manifestations in a Chinese family with familial amyloid polyneuropathy due to a TTR Gly83Arg mutation

PURPOSE

To describe the characteristic ophthalmic phenotypes of a large Chinese family with familial amyloid polyneuropathy due to a missense mutation in transthyretin (TTR) (c.307 C>G).

METHODS

Twenty-seven individuals (12 affected, 15 unaffected) from a five-generation Chinese family underwent general medical examination and comprehensive ophthalmic examination, including best correct visual acuity, intraocular pressure measurements, Schirmer test, slitlamp examination, fundoscopy, and ocular ultrasonography. Histological examination of vitreous biopsies using Congo red staining and immunohistochemistry was performed. Cardiovascular magnetic resonance (CMR), electrocardiogram, and echocardiogram were used to evaluate cardiac amyloidosis. Electromyography was used to evaluate nerve function. All four exons of TTR were amplified by PCR, sequenced using a Bigdye terminator v3.1 cycle sequencing kit and analyzed on an ABI 3700XL Genetic Analyzer.

RESULTS

All 12 affected individuals in the family had ocular manifestations, including severe vitreous opacities, secondary glaucoma, xerophthalmia, dyscoria, and attenuated retinal arteries. Congo red staining demonstrated amyloid deposits in the vitreous, and immunohistochemical staining confirmed the deposition of TTR proteins in the vitreous. Twelve individuals had polyneuropathy, and electromyography detected functional damage in peripheral nerves. One individual was diagnosed with cardiac amyloidosis by CMR. Direct sequencing revealed the heterozygous missense mutation in TTR (c.307 C>G p.Gly83Arg) in all 12 affected individuals. The mutation co-segregated with the disease phenotype and was absent in 100 normal controls.

CONCLUSIONS

Vitreous opacity is very common in patients with the TTR Gly83Arg mutation; other clinical characteristics associated with the mutation include polyneuropathy and cardiac amyloidosis.

Vitreous surgery impact in glaucoma development in liver transplanted familial amyloidosis ATTR V30M Portuguese patients

PURPOSE

Familial amyloidosis with polyneuropathy (FAP) sometimes courses with vitreous amyloid. The aim of this study was to evaluate the incidence of glaucoma after vitrectomy in FAP patients.

METHODS

A total of 79 eyes of 42 liver transplanted FAP patients and 16 eyes of 16 non-FAP patients with rhegmatogenous retina detachment were collected. The patients were divided in to three groups: Group I - FAP patients with vitreous opacities submitted to vitrectomy, Group II - FAP patients without vitreous opacities and not submitted to vitrectomy and, Group III - non-FAP patients with rhegmatogenous retinal detachment submitted to vitrectomy. The Group I was subdivided into: Ia - "complete" vitrectomy; Ib - "incomplete" vitrectomy. The onset of glaucoma was considered when the intraocular pressure level was higher than 21 mmHg, with concomitant visual field abnormalities and optic nerve cupping.

RESULTS

Post vitrectomy glaucoma was more frequent in Group I (56.1%) than in Group III (12.5%) and in Group II (10.5%). We observed a higher incidence of glaucoma in the Ia than in the Ib subgroup (86.4 vs. 21.1%) and earlier appearance in subgroup Ia (7.9 ± 3.6 vs. 39.5 ± 6.6 months).

CONCLUSION

Vitrectomy induced the development of glaucoma in FAP patients.

Transthyretin synthesis in rabbit ciliary pigment epithelium

Ocular symptoms of transthyretin (TTR)-related familial amyloidotic polyneuropathy (FAP) suggest that ciliary pigment epithelium (CPE) may synthesize TTR and its TTR may lead to amyloid formation in addition to TTR from vessels and retinal pigment epithelium (RPE). To clarify sites of TTR synthesis in ocular tissues, we performed in situ hybridization and reverse transcription-polymerase chain reaction (RT-PCR) for qualitative detection of TTR mRNA. In addition, we quantified levels of TTR mRNA expression by means of real-time quantitative RT-PCR. Furthermore, although TTR is an anti-acute phase protein in serum level, no reports on changes in TTR expression in ocular tissues during acute inflammation exist. To investigate changes in TTR expression in ocular tissues during inflammation, we induced uveitis by endotoxin challenge in rabbits and used real-time quantitative RT-PCR to examine changes in TTR mRNA expression in ocular tissues. In situ hybridization and RT-PCR qualitatively demonstrated TTR mRNA not only in RPE but also in CPE. Real-time quantitative RT-PCR showed that the level of TTR mRNA expression in the CPE was about one-third of that in the RPE. TTR mRNA expression in ocular tissues decreased as the degree of inflammation increased. These results suggest that TTR synthesized in the CPE may lead to ocular manifestations, especially glaucoma, in FAP. TTR mRNA also acts as an anti-acute phase reactant in ocular tissues.

Exfoliation syndrome

Exfoliation syndrome (XFS) is an age-related disease in which abnormal fibrillar extracellular material is produced and accumulates in many ocular tissues. Its ocular manifestations involve all of the structures of the anterior segment, as well as conjunctiva and orbital structures. Glaucoma occurs more commonly in eyes with XFS than in those without it; in fact, XFS has recently been recognized as the most common identifiable cause of glaucoma. Patients with XFS are also predisposed to develop angle-closure glaucoma, and glaucoma in XFS has a more serious clinical course and worse prognosis than primary open-angle glaucoma. There is increasing evidence for an etiological association of XFS with cataract formation, and possibly with retinal vein occlusion. XFS is now suspected to be a systemic disorder and has been associated preliminarily with transient ischemic attacks, stroke, systemic hypertension, and myocardial infarction. Further ramifications await discovery. Deposits of white material on the anterior lens surface are the most consistent and important diagnostic feature of XFS. The classic pattern consists of three distinct zones that become visible when the pupil is fully dilated. Whereas the classic picture of manifest XFS has been often described, the early stages of beginning exfoliation have not been well defined. Next to the lens, exfoliation material is most prominent at the pupillary border. Pigment loss from the iris sphincter region and its deposition on anterior chamber structures is a hallmark of XFS. Despite extensive research, the exact chemical composition of exfoliation material (XFM) remains unknown. An overproduction and abnormal metabolism of glycosaminoglycans have been suggested as one of the key changes in XFS. The protein components of XFM include both noncollagenous basement membrane components and epitopes of the elastic fiber system such as fibrillium. Regardless of etiology, typical exfoliation fibers have been demonstrated electron microscopically in close association with the pre-equatorial lens epithelium, the nonpigmented ciliary epithelium, the iris pigment epithelium, the corneal endothelium, the trabecular endothelium, and with almost all cell types of the iris stroma, such as fibrocytes, melanocytes, vascular endothelial cells, pericytes, and smooth muscle cells. The presence of XFS should alert the physician to the increased risks of intraocular surgery, most commonly zonular dehiscence, capsular rupture, and vitreous loss during cataract extraction. Heightened awareness of this condition and its associated clinical signs are important in the detection and management of glaucoma, and preoperative determination of those patients at increased risk for surgical complications.