Topical administration of tacrolimus and corticosteroids in tapering doses is effective in preventing immune rejection in high-risk keratoplasty: a 5-year follow-up study

The ocular immunological alterations in the process of high-risk corneal transplantation rejection

PURPOSE

This study aims to reveal the immunopathogenesis of the high-risk corneal transplantation using a comparative proteomic approach.

METHODS

The immunological properties of ocular tissues (including corneal grafts, aqueous humour, and iris-ciliary body) were analysed using a high-risk rabbit corneal transplantation model employing a comparative proteomic approach.

RESULTS

The corneal grafts revealed a dramatic increase in the immune response both at the early (postoperative day 7) and rejection stages, along with the appearance of transplantation stress-induced cellular senescence in the early stage. The aqueous humour (AH) displayed persistent pathological alterations, indicated by the significant enrichment of complement and coagulation cascades pathway in the early stage and interleukin (IL)-17 signalling pathway in the rejection stage. More surprisingly, the pronounced elevation of immune response was also observed in the iris-ciliary body (I-CB) tissues at the early and rejection stages. The enriched immune-related pathways were associated with antigen processing and presentation, complement and coagulation cascades, and IL-17 signalling pathway. Furthermore, proteomic analysis revealed that the implantation of Cyclosporine A drug delivery system (CsA-DDS) into the anterior chamber obviously mitigated corneal transplantation rejection by inhibiting immunoreaction both in the corneal grafts and I-CB tissues.

CONCLUSION

The results highlighted the involvement of intraocular immunity both in the grafts and I-CB tissues during corneal transplantation rejection, further suggesting the anterior chamber as an optimal drug-delivery site for its treatment.

Nanoparticle-hydrogel composite as dual-drug delivery system for the potential application of corneal graft rejection

Immune rejection remains the major cause of corneal graft failure. Immunosuppressants (such as rapamycin; RAPA) adjunctive to antibiotics (such as levofloxacin hydrochloride; Lev) are a clinical mainstay after corneal grafts but suffer from poor ocular bioavailability associated with severe side effects. In this study, we fabricated a Lev@RAPA micelle loaded cationic peptide-based hydrogel (NapFFKK) as a dual-drug delivery system by integrating RAPA micelles with Lev into a cationic NapFFKK hydrogel to potentially reduced the risk of corneal graft rejection. The properties of the resulting hydrogels were characterized using transmission electronmicroscopy and rheometer. Lev@RAPA micelles loaded NapFFKK hydrogel provided sustained in vitro drug release without compromising their inherent pharmacological activities. Topical instillation of Lev@RAPA micelles loaded NapFFKK hydrogel resulted in the great ocular tolerance and extended precorneal retention over 60 min, thus significantly enhancing the ocular bioavailability of both Lev and RAPA. Overall, such dual-drug delivery system might be a promising formulation for the suppression of corneal graft failure.

Topical tacrolimus for high-risk corneal transplantation: a randomized, clinical trial

BACKGROUND

The prevalence of rejection is 10-30% in penetrating keratoplasty (PKP) case, and the rate is higher in cases of high-risk patients. Although using topical corticosteroids is a standard method for management the rejection of post-PKP patients, it may not be sufficiently potent in high-risk patients. Topical administration of tacrolimus (TAC) may be effective in suppression rejection after corneal transplantation. This study aimed to investigate the efficacy and safety of topical TAC in high-risk PKP patients in Japan.

METHODS

This study was a single centre, single-blinded, randomized controlled trial. Patients with a history of PKP, graft rejection, atopic dermatitis, or deep corneal neovascularisation who underwent PKP were enrolled. They were randomly assigned to receive 0.1% TAC ophthalmic suspension or artificial tear (AT) up to week 52 after surgery. All participants received 0.1% betamethasone up to week 13 after surgery then they received 0.1% fluorometholone up to week 52. The incidence of immunological rejection during the observation period was the main outcome measure in this study.

RESULTS

Thirty patients were enrolled in this study, and 12 eyes in the TAC group and 13 eyes in the AT group completed the study, respectively. Five out of 30 patients discontinued participation after providing informed consent. No serious adverse effects were developed in patients who received 0.1% TAC ophthalmic suspension. No rejection episodes occurred in the TAC group, while one eye in the AT group had rejection. Graft clarity, best spectacle-corrected visual acuity, intraocular pressure, and corneal endothelial cell density were not significantly different between the TAC and AT groups.

CONCLUSION

Our results demonstrated that good tolerability of 0.1% TAC ophthalmic suspension. However, we failed to demonstrate its efficacy in preventing immunological rejection in high-risk patients undergoing PKP.

TRIAL REGISTRATION

This study was first registered in the University Hospital Medical Information Network (UMIN000029669, Date of registration: November 1, 2017). With the enforcement of the Clinical Trial Act in Japan, the study re-registered in the Japan Registry of Clinical Trials (jRCTs031180342, Date of registration: March 18, 2019).

Topical Tacrolimus Compared With Oral Tacrolimus for Postoperative Immunosuppression in Primary Keratolimbal Allograft

PURPOSE

The aim of this study was to compare outcomes between topical tacrolimus and oral tacrolimus as the primary calcineurin inhibitor for postoperative immunosuppression after primary keratolimbal allograft (KLAL) transplantation for limbal stem cell deficiency (LSCD).

METHODS

We performed a retrospective, comparative cohort study at a single tertiary referral center (University of MN) of all patients who underwent primary KLAL between 2014 and 2021. Eyes were grouped into those which received topical tacrolimus as the only calcineurin inhibitor (topical group) and eyes in which patients received oral tacrolimus with or without topical tacrolimus (oral group). Clinical and donor tissue data were obtained and compared between the 2 groups.

RESULTS

In total, 27 eyes of 22 patients (median age 42 years, range 20-79 years) were included, of which 18 eyes were in the oral group and 9 eyes were in the topical group. The mean follow-up time was 33.2 ± 22.6 months. The most frequent etiology of LSCD was alkaline burn (33.3%). At 36 months, graft failure occurred in 6 eyes in the oral group (33.3%) and 2 eyes in the topical group (22.1%) ( P = 0.57). The failure rate in the oral group was 9.1 per 1000 person-months versus 8.4 per 1000 person-months in the topical group ( P = 0.96). The median improvement in BCVA was logMAR -0.975 and logMAR -0.45 for the oral and topical group, respectively ( P = 0.50).

CONCLUSIONS

With careful patient selection, topical tacrolimus may be a viable alternative to oral tacrolimus in KLAL.

Topical tacrolimus in high-risk corneal transplants

PURPOSE

The purpose of this study was to assess the use of topical tacrolimus ointment in preventing rejection in high-risk corneal grafts, when added to the standard immunosuppressive regimen.

METHODS

We conducted an observational, retrospective study using clinical data of high-risk patients subjected to penetrating keratoplasty, who were treated with topical tacrolimus ointment 0.2 mg/g twice a day plus topical dexamethasone 0.1 mg/ml 6 id and compared it with a similar control group treated with topical dexamethasone 0.1 mg/ml 6 id alone. High-risk status was attributed to patients with previous ipsilateral corneal graft failure, two or more quadrants with corneal neovascularization or an infectious or inflammatory corneal disease.

RESULTS

We analysed 53 patients in the trial group versus 53 patients in the control group, with similar age, baseline diagnosis and risk factors, and median follow-up times of 30 and and 24 months, respectively. Survival analysis showed a higher graft survival rate at all follow-up periods for patients treated with topical tacrolimus (p < 0.01). No adverse reactions were reported.

DISCUSSION

This study shows that topical tacrolimus ointment increases the survival rate of the graft if added to the previous topical steroid regimen in high-risk patients.

CONCLUSION

Topical tacrolimus is safe and effective in prolonging graft survival in high-risk patients.