Effect of immunosuppressive agents on long-term survival of renal transplant recipients: focus on the cardiovascular risk

Dendritic cell adhesion is enhanced on endothelial cells preexposed to calcineurin inhibitors

Chronic rejection remains a major complication in solid organ transplantation. Host alloreactive T cells (TC) can be activated by donor dendritic cells (DCs; direct allorecognition) or by recipient DCs (indirect allorecognition). A fundamental aspect of DC function is vascular invasion to present donor antigens to recipient naive TC in secondary lymphoid organs. We investigated the impact of calcineurin inhibitors on DC binding and transmigration to allogeneic human microvascular endothelial cells (ECs) with and without blocking of specific adhesion molecules. Recipient immature DCs were generated by culturing CD14 human peripheral blood monocytes with GM-CSF and IL-4. DC adhesion and transmigration were investigated on allogeneic ECs preincubated with increasing concentrations of cyclosporine and tacrolimus. Experiments were repeated in the presence of blocking antibodies against LFA-1, PECAM-1, VCAM-1, and ICAM-1. Endothelial stimulation with cyclosporine A (100 and 300 ng/mL) and tacrolimus (15 ng/mL) significantly enhanced DC-EC adhesion and transmigration (P<0.01). LFA-1 blockade on DCs significantly reduced cyclosporine- and tacrolimus-induced DC adhesion (P<0.001). VCAM-1 blockade on ECs partially reversed cyclosporine-induced DC adhesion (P<0.001), whereas DC adhesion under tacrolimus exposure was significantly decreased by ICAM-1 (P<0.01) and PECAM-1 (P<0.001) blockade. DC binding and transmigration on allogeneic ECs exposed to calcineurin inhibitors is concentration-dependently increased. Different adhesion molecule patterns on ECs are responsible for enhanced DC invasion under cyclosporine and tacrolimus exposure. We speculate that long-term immunosuppression mediates enhanced invasion of recipient DCs to the donor organ and therefore may aggravate chronic rejection.

Potential cardiovascular risk factors in paediatric renal transplant recipients

Cyclosporin (CsA) therapy is associated with side effects such as hypertension, hyperlipidemia and nephrotoxicity. Tacrolimus (Tac) has been shown to be more favourable in this respect. We retrospectively analysed office blood pressure (BP), serum total cholesterol (TC) and fasting glucose levels, and estimated graft function profiles in paediatric (n =56) and young adult (n =14) renal transplant recipients whose maintenance immunosuppressive regimen was based upon CsA (n =38) or Tac (n =32) given with mycophenolate mofetil and corticosteroids. The analysis was performed at four different time-points: at 1, 6, 12, and 24 months post-transplant, respectively. Baseline characteristics were comparable between treatment groups. Differences for both systolic and diastolic BP, and graft function between treatment groups became significant from month 1 and throughout the 2-year period. Values (mean +/- SD) for CsA-treated and Tac-treated recipients at 2 years were 118.8+/-11.1 / 74.6+/-7.4 mmHg vs 109.3+/-11.2 / 67.2+/-7.8 mmHg for systolic and diastolic BP, respectively, p <0.005/0.005; and 72.0+/-18.5 ml/min vs 84.0+/-22.4 ml/min per 1.73 m(2) for graft function, respectively, p <0.01. Office hypertension, defined as the use of antihypertensive medication at month 24, was significantly associated with CsA-therapy (chi(2), p <0.01). TC levels became significantly lower at months 6, 12, and 24 in the Tac group compared with the CsA group. Hypercholesterolemia, defined as TC>or=200 mg/dl, was significantly associated with CsA-based immunosuppressive regimen at months 6, 12, and 24 post-transplant (chi(2), p <0.05, p <0.001, and p <0.01, respectively). Although Tac therapy was associated with higher glucose levels, no recipient developed post-transplant diabetes mellitus. The number of recipients who experienced acute rejections was comparable in both groups. In conclusion, Tac-based immunosuppressive therapy was found to be associated with more favourable potential risk-factor profiles for cardiovascular disease and better graft function at 2 years post-transplant compared with CsA-therapy.

Cardiovascular risk profile with the new immunosuppressive combinations after renal transplantation

Cardiovascular disease remains the main cause of death among kidney transplant patients. Cardiovascular risk burden already present at the moment of transplantation is substantially worsened by chronic use of immunosuppressants. On the other hand, chronic allograft nephropathy, a clinical-pathological result of immunological and non-immunological damage of the graft, is the main cause of graft loss in the long-term. Among the non-immunological factors contributing to the development of chronic allograft nephropathy, cardiovascular risk factors also seem to play a role. In the present review, we analyse the impact of the different immunosuppressive medications on cardiovascular risk factors after renal transplantation, including renal function.

Sirolimus Monotherapy: Feasible Immunosuppression for Long-Term Follow-up of Kidney Transplantation???A Pilot Experience

Chronic allograft nephropathy (CAN), cardiovascular mortality, and posttransplant malignancy are complications of conventional immunosuppression after kidney transplantation. The aim was to study feasibility of sirolimus (SRL) maintenance monotherapy in a pilot experience. All patients with SRL monotherapy of at least 6 months follow-up were included. In 19 patients, age 58 (34-74) years, SRL monotherapy was introduced 98.1 (49-193) months after transplantation by withdrawing concomitant immunosuppressants from protocols already including SRL or introducing SRL and withdrawing other immunosuppressants. Follow-up is 20.0 (6-41) months. One patient died from hepatocellular carcinoma, diagnosed before SRL monotherapy, with functioning graft. No rejections occurred. SRL trough concentration was 10.7 (4.6-16.1) microg/L. Creatinine (1.77 [1.0-2.9] mg/dL vs. 1.68 [0.8-3.3] mg/dL after 6 months, 1.97 [0.8-4.6] mg/dL at last follow-up; P=NS). Proteinuria increased tendentially (333 [67-893] vs. 890 [46-4011] mg/day). No significant changes of hemoglobin, triglycerides, or cholesterol occurred. SRL monotherapy late after kidney transplantation is feasible in selected patients.

Mycophenolate mofetil vs. azathioprine is associated with decreased acute rejection, late acute rejection, and risk for cardiovascular death in renal transplant recipients with pre-transplant diabetes

Outcomes specifically in mycophenolate mofetil (MMF)-treated diabetic renal transplant patients have not been previously reported. This study compared acute rejection (AR), late acute rejection (LAR), patient survival [and specifically death from cardiovascular (CV), infectious and malignant causes], incidence of post-transplant malignancies, and graft loss in MMF- or azathioprine (AZA)-treated renal transplant patients with pre-transplant diabetes. Outcomes were compared between MMF- (n = 14 144) and AZA- (n = 3001) treated diabetic patients using the Scientific Registry of Transplant Recipients data on all U.S. adult renal transplants performed between 1995 and 2002. Statistical analyses included Kaplan-Meier survival analysis, Cox multivariable regression and chi-square tests. MMF patients had less AR compared with AZA-treated patients (23.5% vs. 28.3%, p < 0.001) and less risk for LAR over 4 yr [hazard ratio (HR): 0.64, 95% CI 0.44, 0.92; p = 0.02]. While time to any-cause death did not differ between the groups, MMF treatment was associated with a 20% decreased risk of CV death (HR: 0.80, 95% CI 0.67, 0.97; p = 0.020) compared with AZA treatment. MMF patients also had a lower incidence of malignancies than AZA patients (2.2% vs. 3.7%, p < 0.001). These results suggest treatment with MMF compared with treatment with AZA in diabetic transplant patients is associated with less AR, less risk of LAR, a decreased risk of CV death, and a lower incidence of malignancies.