ABSTRACT
AIMS: To evaluate the efficacy and safety of topically applied mycophenolate mofetil (MMF) for the prophylaxis of corneal graft rejection in an experimental keratoplasty model. METHODS: A total of 12 female Lewis rats received 3.5-mm MHC I/II-incompatible corneal grafts from DA donors. Recipients were randomly assigned to receive either topical MMF + beta-cyclodextrin therapy (1%), beta-cyclodextrin therapy alone or to remain untreated. Therapy was applied every 2 h (over 24 h) during the first 3 postoperative days, then twice hourly during daytime. Grafts were graded every day based on a rejection score including the parameters transplant clarity and edema. RESULTS: The mean survival time (MST) of the grafts in the MMF-treated group was 12 days, the MST in the vehicle-treated group was 14.3 days and the MST in the untreated group was 13.3 days. So, the survival curves of the 3 treatment groups did not differ significantly. CONCLUSION: Topical MMF is ineffective for prophylaxis of corneal graft rejection.
Subject(s)
Corneal Transplantation , Graft Rejection/drug therapy , Graft Survival/drug effects , Immunosuppressive Agents/pharmacology , Mycophenolic Acid/analogs & derivatives , Administration, Topical , Animals , Disease Models, Animal , Female , Graft Rejection/prevention & control , Immunosuppressive Agents/chemistry , Mycophenolic Acid/chemistry , Mycophenolic Acid/pharmacology , Ophthalmic Solutions , Rats , Rats, Inbred Lew , Transplantation, Homologous , Treatment Failure , beta-Cyclodextrins/pharmacologyABSTRACT
BACKGROUND: New insights into the molecular mechanisms of corticosteroid-mediated actions have revealed new substances, such as selective glucocorticoid receptor agonists (SEGRA), for the treatment of inflammatory diseases. We set out to evaluate the effect of a SEGRA compound following topical application on the course of experimental orthotopic corneal grafts. METHODS: A total of 42 female Lewis rats received 3.5-mm MHC I/II-incompatible corneal grafts from DA donors. Recipients were randomly assigned to receive either no therapy, 0.25% cyclodextrin-encapsulated SEGRA compound in a new microemulsion formulation or carrier system only. All treatments started on the day of surgery and were given five times daily for 35 days. Grafts were graded every day and a rejection score was generated based on cornea clarity and edema. In addition, intragraft mRNA expression of CD3, IFN-gamma, TNF-alpha, IL-10 and IL-4 was analyzed using real-time RT-PCR analysis at day 7 after transplantation before rejection occurred in additional control animals. RESULTS: Topical application of a SEGRA compound was highly effective in prolonging the mean survival time of corneal grafts (42.2+/-4.0 days) compared with untreated controls (11.7+/-1.2 days, p=0.00003) or animals that received the vehicle only (15.0+/-1.5 days, p=0.114). In addition, real-time RT-PCR analysis of SEGRA-treated grafts revealed lower mRNA expression of intragraft cytokines; the difference was significant for IL-4 (p<0.05). CONCLUSIONS: Our results indicate that topical application of a SEGRA compound significantly prolongs corneal graft survival in an experimental keratoplasty model. It further suggests that SEGRA can be a potentially useful drug to suppress the immune response.
Subject(s)
Graft Rejection/prevention & control , Graft Survival/drug effects , Heterocyclic Compounds, 2-Ring/administration & dosage , Hydrocarbons, Halogenated/administration & dosage , Keratoplasty, Penetrating , Receptors, Glucocorticoid/agonists , Administration, Topical , Animals , CD3 Complex/genetics , CD3 Complex/metabolism , Cornea/metabolism , Cyclodextrins , Drug Carriers , Female , Graft Rejection/metabolism , Interferon-gamma/genetics , Interferon-gamma/metabolism , Interleukin-10/genetics , Interleukin-10/metabolism , Interleukin-4/genetics , Interleukin-4/metabolism , RNA, Messenger/metabolism , Rats , Rats, Inbred Lew , Reverse Transcriptase Polymerase Chain Reaction , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolismABSTRACT
The efficacy of mycophenolate mofetil (MMF), a prodrug of mycophenolic acid (MPA), in high risk keratoplasties and ocular immune-mediated diseases has been shown in recent years. As peroral administration of MMF can cause various side effects, topical application should be considered. This study investigates the intraocular availability of MMF and MPA in the rabbit eye. An eye drop solution (MMF-CD; 1% MMF/10% hydroxypropyl-beta-cyclodextrin (HP-beta-CD)) or a 1% aqueous suspension (MMF-SP) was instilled into the lower cul-de-sac of the right eye of each rabbit. Rabbits (each group: n = 4) were put down after 30, 60 and 240 min. Aqueous humor, vitreous, cornea, sclera, conjunctiva, iris-ciliary-body, and plasma were isolated. Several extraction procedures were performed in order to quantify the drug by HPLC. The aqueous humor concentration of the active metabolite MPA was 24 microg/mL after 30 min for both preparations. The ratio of the MPA concentrations after 30, 60, and 240 min was 1 : 2 : 0.07 for MMF-CD and 1 : 0.6 : 0.04 for MMF-SP, respectively. MPA levels in the cornea were 90.78 / 56.90 / 4.08 x 10(-6) microg/microg for MMF-CD, whereas MMF-SP resulted in MPA levels of 102.65 / 31.18 / 2.59 x 10(-6) microg/microg at the three time points. As a high concentration of the active drug MPA in cornea and aqueous humor is desired, e.g. following corneal transplantation, the MMF/HP-beta-CD formulation could be an useful topical treatment. Furthermore, the present study shows that MMF-CD is superior to MMF-SP by increasing intraocular availability.
