Efficacy of postoperative immunosuppression after keratoplasty in herpetic keratitis

In vivo CRISPR gene editing in patients with herpetic stromal keratitis

In vivo CRISPR gene therapy holds large clinical potential, but the safety and efficacy remain largely unknown. Here, we injected a single dose of herpes simplex virus 1 (HSV-1)-targeting CRISPR formulation in the cornea of three patients with severe refractory herpetic stromal keratitis (HSK) during corneal transplantation. Our study is an investigator-initiated, open-label, single-arm, non-randomized interventional trial at a single center (NCT04560790). We found neither detectable CRISPR-induced off-target cleavages by GUIDE-seq nor systemic adverse events for 18 months on average in all three patients. The HSV-1 remained undetectable during the study. Our preliminary clinical results suggest that in vivo gene editing targeting the HSV-1 genome holds acceptable safety as a potential therapy for HSK.

Epithelial Keratitis After Cataract Surgery

PURPOSE

To evaluate the incidence, related perioperative factors, clinical characteristics, and possible etiologies of epithelial keratitis after cataract surgery.

METHODS

A retrospective chart review of 666 eyes in 666 patients who underwent cataract surgery was performed to evaluate the incidence of epithelial keratitis and related factors in the postoperative period.

RESULTS

Postoperative epithelial keratitis developed in 15 eyes. Eleven of the 15 eyes were diagnosed with herpes simplex keratitis (HSK); 10 of the 11 eyes were diagnosed by polymerase chain reaction, and the remaining 1 eye by clinical diagnosis. All patients diagnosed with HSK had no previous clinical history of the infection before undergoing cataract surgery. Initially, the diagnosis of all 15 eyes was toxic keratitis, but the final diagnosis of 11 of the initial 15 was found to be epithelial herpes keratitis. The incision location was shown to be related to the occurrence of HSK in our study (P < 0.05).

CONCLUSIONS

HSK epithelial keratitis after cataract surgery is a relatively uncommon complication and can be misdiagnosed in its early disease course because of its relative rarity. This study explores the possibility that the temporal corneal penetrating incisional approach used in routine cataract surgery interrupts the corneal nerves and subsequently can trigger reactivation of HSK.

Long-term outcomes of the Boston type I keratoprosthesis in eyes with previous herpes simplex virus keratitis

Purpose

To report the long-term outcomes of the Boston type I keratoprosthesis (Kpro) in eyes with prior herpes simplex virus (HSV) keratitis.

Methods

Retrospective review of all Kpro procedures performed by a single surgeon from 1 May 2004 to 1 January 2015.

Results

13 of 173 Kpro procedures were performed in 11 eyes with prior HSV keratitis. There was not a significant difference in the percentage of eyes with and without prior HSV keratitis with preoperative (9% vs 8%, p=1.00) or postoperative (57% vs 60%, p=1.00) corrected distance visual acuity (CDVA) ≥20/200 or in the percentage of contralateral eyes with preoperative CDVA ≥20/50 (55% vs 30%, p=0.18). While several postoperative complications occurred approximately twice as often in eyes with prior HSV keratitis, including persistent epithelial defect (63.6% vs 34.1%; p=0.10), corneal infiltrate (27.3% vs 12.3%; p=0.17) and sterile vitritis (18.2% vs 9.4%; p=0.31), only cystoid macular oedema (45.5% vs 12.3%; p=0.01) was significantly more common. Similarly, while the Kpro retention failure rate in eyes with prior HSV keratitis was twice than that in eyes without it (0.15 vs 0.07 per year), the difference was not statistically significant (p=0.09).

Conclusion

As greater than half of patients with unilateral HSV keratitis undergoing Kpro implantation have CDVA ≥20/50 in the contralateral eye, and as the Kpro retention failure rate in eyes with prior HSV keratitis is twice than that in eyes without prior HSV keratitis, caution should be exercised when considering Kpro implantation in these patients.

Update on the Management of High-Risk Penetrating Keratoplasty

PURPOSE OF REVIEW

In this article, we review the indications and latest management of high-risk penetrating keratoplasty.

RECENT FINDINGS

Despite the immune-privilege status of the cornea, immune-mediated graft rejection still remains the leading cause of corneal graft failure. This is particularly a problem in the high-risk graft recipients, namely patients with previous graft failure due to rejection and those with inflamed and vascularized corneal beds. A number of strategies including both local and systemic immunosuppression are currently used to increase the success rate of high-risk corneal grafts. Moreover, in cases of limbal stem cell deficiency, limbal stem cells transplantation is employed.

SUMMARY

Corticosteroids are still the top medication for prevention and treatment in cases of corneal graft rejection. Single and combined administration of immunosuppressive agents e.g. tacrolimus, cyclosporine and mycophenolate are promising adjunctive therapies for prolonging graft survival. In the future, cellular and molecular therapies should allow us to achieve immunologic tolerance even in high-risk grafts.

Long-term Outcomes of Pediatric Penetrating Keratoplasty for Herpes Simplex Virus Keratitis

PURPOSE

To analyze the characteristics and long-term outcomes of patients that underwent pediatric penetrating keratoplasty (PPK) for herpes simplex virus (HSV) keratitis.

DESIGN

Retrospective, interventional, consecutive case series.

METHODS

Observational report of outcomes and findings for 9 patients with history of HSV keratitis that underwent PPK and were followed in a single institution. Difference between the median preoperative and final best-corrected visual acuity (BCVA) was assessed and the outcomes are reported.

RESULTS

We included 9 eyes; median age at the moment of the PPK was 14 years. The median initial BCVA was 20/400 (range 20/60 to hand motion) and final was 20/50 (range 20/30 to 20/400) (P < .05). Follow-up was a median of 94 months. Complications in these patients included glaucoma (1), graft rejection (1), recurrence of disease (1), and amblyopia (3). No graft failures were present.

CONCLUSION

The long-term outcomes with PPK for HSV keratitis in children provide improvement in BCVA when not compromised by amblyopia.

Systemic Immunomodulatory Strategies in High-risk Corneal Transplantation

The cornea is the most commonly transplanted tissue in the body. Although corneal grafts generally have high success rates, transplantation onto inflamed and vascularized host beds, or so-called high-risk corneal transplantation, has a high rate of graft rejection. The management of this high-risk corneal transplantation is challenging and involves numerous measures. One of the key measures to prevent graft rejection in these cases is the use of systemic immunosuppressive agents. In this article, we will review the systemic immunosuppressive agents most commonly used for high-risk corneal transplantation, which include corticosteroids, cysclosporine A, tacrolimus, mycophenolate mofetil, and rapamycin. Benefits, risks, and published data on the use of these medications for high-risk corneal transplantation will be detailed. We will also summarize novel immunoregulatory approaches that may be used to prevent graft rejection in high-risk corneal transplantation.

Management of high-risk corneal transplantation

The cornea is the most commonly transplanted tissue in medicine. The main cause of corneal graft failure is allograft rejection. The incidence of graft rejection depends on the presence of high-risk characteristics, most notably corneal neovascularization. Although corneal grafting has high success rates in the absence of these risk factors, high-risk keratoplasty is associated with low success rates because of a high incidence of immune-mediated graft rejection. To improve the survival of high-risk corneal transplantation, various preoperative, intraoperative, and postoperative measures can be considered; however, the key step in the management of these grafts is the long-term use of local and/or systemic immunosuppressive agents. Although a number of immunosuppressive agents have been used for this purpose, the results vary significantly across different studies. This is partly due to the lack of an optimized method for their use, as well as the lack of a precise stratification of the degree of risk in each individual patient. New targeted biologic treatments, as well as tolerance-inducing methods, show promising horizons in the management of high-risk corneal transplantation in near future.

Systemic Immunosuppression in High-Risk Penetrating Keratoplasty: A Systematic Review

Cornea transplantation has a high success rate and typically only requires topical immunomodulation. However, in high-risk cases, systemic immunosuppression can be used. We conducted a systematic review on the efficacy and side effects of systemic immunosuppression for high-risk cornea transplantation. The study population was 18 years old or older with a high-risk transplant (two or more clock hours of cornea vascularization or a previous failed graft or a graft needed because of herpes simplex keratitis). A comprehensive search strategy was performed with the help of an information specialist and content experts from ophthalmology. All study designs were accepted for assessment. Level 1 and level 2 screening was performed by two reviewers followed by data abstraction. Forest plots were created whenever possible to synthesize treatment effects. Quality assessment was done with a Downs and Blacks score. From 1,150 articles, 29 were ultimately used for data abstraction. The odds ratios (ORs) for clear graft survival in cyclosporine and controls were 2.43 (95% CI: 1.00 - 5.88) and 3.64 (95% CI: 1.48 - 8.91) for rejection free episodes. Mycophenolate mofetil (MMF) significantly improved the rejection free graft survival rates at 1 year (OR: 4.05, 95% CI: 1.83 - 8.96). The overall results suggested that both systemic cyclosporine and MMF improved 1-year rejection free graft survival in high-risk keratoplasty. Cyclosporine also significantly improved clear graft survival rates at 1 year; however, there were insufficient data to analyze the same in the MMF group. Higher quality studies are needed to understand this issue better.

Adverse effects of low-dose systemic cyclosporine therapy in high-risk penetrating keratoplasty

PURPOSE

The purpose of this study was to investigate the adverse effects of low-dose oral cyclosporine (CsA) therapy following high-risk corneal transplantation.

METHODS

The medical records from 88 subjects who had undergone high-risk penetrating keratoplasties and had been administered oral CsA were retrospectively analyzed. High risk was defined as a history of graft rejection, three or more quadrants of vascularization, or the presence or history of intraocular inflammation. An initial CsA dose of 3-5 mg/kg per day was given for 3-7 days, followed by 2.5-3.5 mg/kg per day for approximately 1 month. The concentration of CsA was maintained at the target trough level of 120-150 ng/ml for at least 6 months or until serious complications developed. The relationship between the cumulative dose and duration of CsA administration and the adverse systemic effects, including the frequency of herpes keratitis, was evaluated. The incidence of herpes keratitis in the study subjects was compared with the incidence in 185 patients who had not received CsA therapy following penetrating keratoplasty.

RESULTS

The mean survival time of the grafts was 33.6 months. Adverse effects occurred in 81.8 % of subjects. Hypertension, elevated liver enzyme levels, elevated serum creatinine level, and decreased absolute neutrophil count (ANC) were observed in 14.8, 6.8, 5.7, and 5.7 % of subjects, respectively. Simvastatin-induced rhabdomyolysis also developed in one case. Some patients exhibited minor complications, with gastrointestinal problems and hypertrichosis recorded in 5.7 and 3.4 % of subjects, respectively. Hypertension and hepatotoxicity most frequently occurred after 4 to 8 weeks of medication, while ANC decrease and nephrotoxicity generally developed after 24 weeks of treatment, with incidence related to the cumulative dose. Herpes keratitis occurred more frequently (31.8 %) in the CsA-treated subjects than in subjects that did not receive CsA therapy (p = 0.005). Most of the adverse effects were reversed after discontinuation of CsA therapy.

CONCLUSION

The results of this study suggest that low-dose oral CsA therapy may induce various adverse effects, the most common of which are herpes keratitis and hypertension.

Three-year corneal graft survival rate in high-risk cases treated with subconjunctival and topical bevacizumab

PURPOSE

To evaluate the effect of combined subconjunctival and topical bevacizumab treatment on corneal graft survival rate in high-risk eyes.

METHODS

Prospective, consecutive, interventional case series. Fifty eyes of 50 high-risk patients scheduled for penetrating keratoplasty (PK) were included in the study; two Stevens-Johnson syndromes (SJS), five corneal combustions due to chemical burn, seven post-traumatic vascularised leucomas, 11 post-infectious vascularised leucomas, 19 rejected grafts and six corneal ulcers. Additional surgeries such as autologous limbal stem cell and/or amniotic membrane transplantation were performed together with PK in ten cases. All eyes received subconjunctival injection of 0.5 ml bevacizumab (25 mg/ml) after PK. Eyes with more than two quadrants of neovascularisation (NV) received bevacizumab drops (25 mg/ml) postoperatively for up to 12 weeks. Donor grafts were followed up for best-corrected visual acuity, graft clarity, change in NV, endothelial cell density loss (ECD), and adverse events. Mean follow-up was 36.5 months (range 32-61).

RESULTS

Best-corrected visual acuity increase was statistically significant in 82 % (41/50) of eyes 3 years after PK (paired t-test, p = 0.02). Thirty-five (70 %) high-risk grafts remained clear throughout the 3-year follow-up period. Decrease of corneal NV was observed in 84 % (42/50) of eyes treated with bevacizumab. ECD changed from preoperative 2,864 ± 301 down to 1,905 ± 187 cells/mm(2) at 3 postoperative years. A non-healing epithelial defect was recorded in one patient with SJS after 12 weeks of topical bevacizumab.

CONCLUSION

Combined subconjunctival and topical bevacizumab treatment may improve corneal graft survival rate in the majority of high-risk cases.

[Postoperative therapy after penetrating keratoplasty in herpes simplex keratitis]

INTRODUCTION

Keratitis due to herpes simplex infection is a common cause of corneal damage resulting in impaired vision.

AIM

The aim of this study was to assess the outcome of penetrating keratoplasties in patients treated with systemic antiviral and immunosuppressive drugs.

METHOD

The authors retrospectively analysed data of 12 patients who underwent penetrating keratoplasty. The average age at onset of the first keratitis preceding surgery was 18 years (between 5 and 40 years). The indication for surgery in 9 cases was to improve vision and in 3 patient to prevent corneal perforation. Nine patients were given both acyclovir and mycophenolate mofetil, as anti-viral agent and immunosuppressive treatment, respectively. Two patients were treated with anti-viral agent only while one patient received no systemic therapy. The average follow-up time was 53.1 months (between 16 and 84 months).

RESULTS

Of the 9 patients who underwent surgery for improving vision, 8 patients had transparent grafts during follow up without vascularization. All eight patients had been treated with acyclovir and mycophenolate mofetil. In one patient who had no systemic treatment recurrence and graft rejection was observed. Only one of the surgeries performed in acute stage of inflammation resulted in a properly healed transparent graft without recurrence and rejection. In this patient acyclivir and mycophenolate mofetil therapy had been given previously. In two cases the preventive - full or partial - systemic treatment had no effect. The visual acuity improved in all cases. In three patients visual acuity was influenced by some other factors as well.

CONCLUSIONS

The systemic acyclovir and mycophenolat mofetil therapy is fairly successful in perforating keratoplasty due to herpes simplex infection. Acyclovir decreases the risk of recurrence, while mycophenolate mofetil may prevent graft rejection. The timing of surgery is decisive; it leads to better results when performed in a scarred, noninflammatory state.

Outcome of corneal transplantation in a private institution in Saudi Arabia

Background

The aim of this work was to describe the indications, complications, and outcomes of penetrating keratoplasty (PKP) in Saudi Arabia.

Methods

In a retrospective, noncomparative interventional case series, the medical records of patients who underwent PKP from January 2000 to December 2008 and had a minimum follow-up of 6 months were reviewed. All corneas were obtained from eye banks in the US. Indications, complications, and outcomes of surgery were recorded. This study was approved by the institutional review board.

Results

Eighty-five consecutive eyes were included in this study. There were 52 (61.2%) males and 33 (38.8%) females. The median age was 35.0 years (range 3–85 years), and the median follow-up period was 24 months (range 6–108 months). The indications for PKP were keratoconus, bullous keratopathy, corneal scars, corneal dystrophy, and corneal regraft. The overall graft survival time was 88.9 months ± 4.9 months (mean ± standard error of mean, 95% confidence interval [CI] 79.4 months –98.4 months) while the 3-year and 5-year cumulative survival rates were 90.7% and 84.3%, respectively. Surgical indication (P = 0.038), immune rejection (P < 0.001), preoperative corneal vascularization (P = 0.022), and perioperative high intraocular pressure (P = 0.032) were associated significantly with corneal graft failure in univariate analysis. Multivariate analysis reduced these significant associations to rejection (P < 0.001) and vascularization (P = 0.009). Relative risk for failure in rejected cornea was 16.22 (95% CI 4.99–52.69) and in vascularized cornea was 3.89 (95% CI 1.36–11.09). At last visit following PKP, 34 (40%) eyes had best spectacle-corrected visual acuity of 20/40 or better, and 51 (60.0%) eyes had 20/80 or better. Best spectacle-corrected visual acuity was worse than 20/400 in 15 (17.6%) eyes.

Conclusion

The overall corneal graft survival in a private setting in Saudi Arabia can be excellent. Thorough preoperative evaluation and comprehensive postoperative management are crucial for successful corneal transplantation. A larger multicenter study is recommended to portray the outcome of private corneal transplantation in Saudi Arabia in general.