Related Experiment Videos
Unbound cyclosporine and allograft rejection after heart transplantation
F Akhlaghi1, A M Keogh, K F Brown
1Department of Pharmacy, University of Sydney, New South Wales, Australia. fa213@cam.ac.uk
Insights
Lower unbound cyclosporine levels correlate with higher cardiac transplant rejection rates. Monitoring cyclosporine fraction unbound (fU) may optimize immunosuppressive therapy and improve patient outcomes after heart transplantation.
Area of Science:
- Pharmacology
- Transplantation Medicine
- Immunology
Background:
- Cyclosporine is a key immunosuppressant post-cardiac transplant.
- Understanding cyclosporine plasma protein binding is crucial for managing organ rejection.
- Variations in unbound cyclosporine levels may influence transplant outcomes.
Purpose of the Study:
- To investigate the relationship between cyclosporine plasma protein binding and cardiac allograft rejection.
- To compare rejection episode incidence based on differing levels of unbound cyclosporine.
Main Methods:
- Forty-six cardiac transplant recipients were monitored for 12 months post-transplant.
- Cyclosporine plasma fraction unbound (fU) was measured using equilibrium dialysis.
- Patients were stratified into low, intermediate, and high unbound cyclosporine groups.
Main Results:
- Higher rates of significant rejection (grades 3a, 3b, 4) observed in the low fU group (40.9%) compared to intermediate (28.5%) and high (32.1%) groups.
- The low fU group experienced a significantly higher incidence of rejection episodes in the first month post-transplant.
- Patients with lower unbound cyclosporine levels had shorter intervals between rejection episodes and required more treatment.
Conclusions:
- Lower unbound cyclosporine levels are associated with an increased risk of cardiac allograft rejection.
- Monitoring cyclosporine fraction unbound may be a clinically significant factor in assessing treatment response.
- Individualized cyclosporine dosing based on fU levels could potentially improve transplant outcomes.
Background:
To determine the impact of cyclosporine plasma protein binding on organ rejection after cardiac transplantation, the incidence of cardiac rejection episodes was compared among patients who had differing levels of cyclosporine plasma fraction unbound (fU).
Methods:
Forty-six consecutive cardiac transplant recipients were sampled at 1, 3, 6, and 12 months after transplantation, and cyclosporine plasma fU was determined, using a specially developed equilibrium dialysis method. At the completion of the study, incidences of cardiac rejection episodes were compared among patients having mean cyclosporine fU (Csfu) that were low (LCsfu; mean+/-SD, 1.33+/-0.10%, n=15), intermediate (ICsfu; 1.60+/-0.07%, n= 16), and high (HCsfu; 1.99+/-0.30%, n=15).
Results:
Percentage of endomyocardial biopsies (grade 3a, 3b, and 4) with respect to the total number of biopsies performed in the first 3 months after transplant was significantly higher in the LCsfu group than the other groups (40.9% in LCsfu vs. 28.5% for ICsfu and 32.1% for HCsfu groups, P=0.02). The linearized rate of rejection (episodes of rejection/100 patient-days) in the first month after transplant was 6.5+/-1.7 for LCsfu, 3.5+/-0.8 for ICsfu and 4.3+/-0.9 for the HCsfu group (P<0.05, low vs. intermediate-high). The mean (95% confidence interval) of time interval between the first and second episodes of rejections was 10.7 (5.6-16.0) days for LCsfu, 18.0 (8.6-29.0) days for the ICsfu, and 26.0 (15.1-36.9) days for the HCsfu group (P<0.01). The total number of rejections requiring treatment per patient in the first 3 months after transplant was higher in the LCsfu group compared with the others (4.0+/-1.7 episodes for LCsfu vs. 2.9+/-1.1 for ICsfu and 3.2+/-1.2 episodes for HCsfu; P<0.05). Four patients in the low group, one patient in the intermediate group, and no patients in the high group required treatment with total lymphoid irradiation (P<0.02).
Conclusions:
This finding suggests that patients with lower levels of cyclosporine fU are more prone to cardiac rejection and that the level of cyclosporine fraction unbound may be clinically important for determination of response to cyclosporine therapy.