Switch of immunosuppression from cyclosporine A to everolimus: impact on pulse wave velocity in stable de-novo renal allograft recipients

Cardiovascular Outcomes in De Novo Kidney Transplant Recipients Receiving Everolimus and Reduced Calcineurin Inhibitor or Standard Triple Therapy: 24-month Post Hoc Analysis From TRANSFORM Study

BACKGROUND

The comparative impact of everolimus (EVR)-based regimens versus standard of care (mycophenolic acid+standard calcineurin inhibitor [MPA+sCNI]) on cardiovascular outcomes in de novo kidney transplant recipients (KTRs) is poorly understood. The incidence of major adverse cardiac events (MACEs) in KTRs receiving EVR+reduced CNI (rCNI) or MPA+sCNI from the TRANSplant eFficacy and safety Outcomes with an eveRolimus-based regiMen study was evaluated.

METHODS

The incidence of MACE was determined for all randomized patients receiving at least 1 dose of the study drug. Factors associated with MACEs were determined by logistic regression. Risk of MACE out to 3 y post-study was calculated using the Patient Outcome in Renal Transplantation equation.

RESULTS

MACE occurred in 81 of 1014 (8.0%; EVR+rCNI) versus 89 of 1012 (8.8%; MPA+sCNI) KTRs (risk ratio, 0.91 [95% confidence interval [CI], 0.68-1.21]). The incidence of circulatory death, myocardial infarction, revascularization, or angina was similar between the arms. Incidence of MACE was similar between EVR+rCNI and MPA+sCNI arms with a higher incidence in prespecified risk groups: older age, pretransplant diabetes (15.1% versus 15.9%), statin use (8.5% versus 10.8%), and low estimated glomerular filtration rate (Month 2 estimated glomerular filtration rate <30 versus >60 mL/min/1.73 m 2 ; odds ratio, 2.23 [95% CI, 1.02-4.86]; P = 0.044), respectively. Predicted risk of MACE within 3 y of follow-up did not differ between the treatment arms.

CONCLUSIONS

Cardiovascular morbidity and mortality were similar between de novo KTRs receiving EVR+rCNI and MPA+sCNI. EVR+rCNI is a viable alternative to the current standard of care in KTRs.

Arterial stiffness and blood pressure increase in pediatric kidney transplant recipients

BACKGROUND

Pulse wave velocity (PWV) is a measure of arterial stiffness. We investigated PWV and blood pressure (BP) to determine to what extent BP changes contribute to arterial stiffness, and secondly, to identify influencing factors on BP in children after kidney transplantation.

METHODS

Seventy children ≥ 2.5 years post-transplantation with at least two PWV measurements were included. Changes of systolic (Δ SBP) and diastolic BP (Δ DBP) were classified into "stable/decreasing," "1-10 mmHg increase," and " > 10 mmHg increase." Linear mixed modeling for PWV z-score (PWVz) adjusted either for Δ SBP or Δ DBP was performed. An extended dataset with monthly entries of BP, immunosuppression, and creatinine was obtained in 35 participants over a median of 74 months to perform linear mixed modeling for SBP and DBP.

RESULTS

PWVz increased with a rate of 0.11/year (95% CI 0.054 to 0.16). Compared to participants with stable BP, those with 1-10-mmHg SBP and DBP increase showed a higher PWVz of 0.59 (95% CI 0.046 to 1.13) and 0.86 (95% CI 0.43 to 1.30), respectively. A > 10-mmHg BP increase was associated with an even higher PWVz (SBP β = 0.78, 95% CI 0.22 to 1.34; DBP β = 1.37, 95% CI 0.80 to 1.94). Female sex and participants with lower eGFR showed higher PWVz. In the extended analysis, DBP was positively associated with cyclosporin A and everolimus trough levels.

CONCLUSIONS

A higher increase of PWV is seen in patients with greater BP increase, with higher cyclosporin A and everolimus trough levels associated with higher BP. This emphasizes the role of BP as a modifiable risk factor for the improvement of cardiovascular outcome after transplantation. A higher resolution version of the Graphical abstract is available as Supplementary information.

Management of cardiac diseases in liver transplant recipients: Comprehensive review and multidisciplinary practice-based recommendations

Cardiac diseases are one of the most common causes of morbidity and mortality following liver transplantation (LT). Prior studies have shown that cardiac diseases affect close to one-third of liver transplant recipients (LTRs) long term and that their incidence has been on the rise. This rise is expected to continue as more patients with advanced age and/or non-alcoholic steatohepatitis undergo LT. In view of the increasing disease burden, a multidisciplinary initiative was developed to critically review the existing literature (between January 1, 1990 and March 17, 2021) surrounding epidemiology, risk assessment, and risk mitigation of coronary heart disease, arrhythmia, heart failure, and valvular heart disease and formulate practice-based recommendations accordingly. In this review, the expert panel emphasizes the importance of optimizing management of metabolic syndrome and its components in LTRs and highlights the cardioprotective potential for the newer diabetes medications (e.g., sodium glucose transporter-2 inhibitors) in this high-risk population. Tailoring the multidisciplinary management of cardiac diseases in LTRs to the cardiometabolic risk profile of the individual patient is critical. The review also outlines numerous knowledge gaps to pave the road for future research in this sphere with the ultimate goal of improving clinical outcomes.

Cardiovascular effects of immunosuppression agents

Immunosuppressive medications are widely used to treat patients with neoplasms, autoimmune conditions and solid organ transplants. Key drug classes, namely calcineurin inhibitors, mammalian target of rapamycin (mTOR) inhibitors, and purine synthesis inhibitors, have direct effects on the structure and function of the heart and vascular system. In the heart, immunosuppressive agents modulate cardiac hypertrophy, mitochondrial function, and arrhythmia risk, while in vasculature, they influence vessel remodeling, circulating lipids, and blood pressure. The aim of this review is to present the preclinical and clinical literature examining the cardiovascular effects of immunosuppressive agents, with a specific focus on cyclosporine, tacrolimus, sirolimus, everolimus, mycophenolate, and azathioprine.

Atorvastatin can delay arterial stiffness progression in hemodialysis patients

Purpose

Arterial stiffness is one of the vascular pathologies in hemodialysis (HD) patients with increased cardiovascular mortality and morbidity. Few approaches have been tested to reduce arterial stiffness in patients with chronic kidney disease (CKD). We aimed to assess effects of atorvastatin on arterial stiffness in hemodialysis patients.

Methods

This research is a double-blinded, placebo-controlled, randomized clinical trial which included 50 patients maintained on regular HD. Patients were allocated to receive 10 mg atorvastatin or placebo for 24 weeks. Aortic pulse wave velocity (PWV) as an index of large artery stiffness and augmentation index (AIx) as an index of wave reflections were assessed at baseline and after 6 months in both groups.

Results

In atorvastatin group at study end, there was no significant difference from baseline findings in aortic PWV (7.86 ± 2.5 vs 7.88 ± 2.6 m/sec; p = 0.136), AIx (26.04 ± 8.5 vs 26.0 ± 8.6%; p = 0.714) and central pulse pressure (PP) (p = 1.0). On the other hand, in placebo group after 24 weeks, aortic PWV (7.80 ± 2.16 vs 7.63 ± 2.1 m/sec; p < 0.001), AIx (25.88 ± 9.4 vs 25.04 ± 9.4%; p < 0.001) increased significantly from baseline measurements but central pulse pressure (PP) (p = 0.870) did not. Also, the change (Δ) in aortic PWV and AIx was significantly higher than the change in the atorvastatin group with p value of < 0.001 and < 0.001, respectively.

Conclusions

Arterial stiffness parameters remained stable in atorvastatin group but increased significantly in placebo-treated patients suggesting a potential role for atorvastatin to delay arterial stiffness progression in HD patients. Larger randomized clinical trials are needed to confirm these findings.

Clinical Trials registration

ClinicalTrials.gov NCT04472637.

Cardiovascular protection associated with cilostazol, colchicine and target of rapamycin inhibitors

ABSTRACT

An alteration in extracellular matrix production by vascular smooth muscle cells is a crucial event in the pathogenesis of vascular diseases such as aging-related, atherosclerosis and allograft vasculopathy. The human target of rapamycin (TOR) is involved in the synthesis of extracellular matrix by vascular smooth muscle cells. TOR inhibitors reduce arterial stiffness, blood pressure, and left ventricle hypertrophy and decrease cardiovascular risk in kidney graft recipients and patients with coronary artery disease and heart allograft vasculopathy. Other drugs that modulate extracellular matrix production such as cilostazol and colchicine have also demonstrated a beneficial cardiovascular effect. Clinical studies have consistently shown that cilostazol confers cardiovascular protection in peripheral vascular disease, coronary artery disease, and cerebrovascular disease. In patients with type 2 diabetes, cilostazol prevents the progression of subclinical coronary atherosclerosis. Colchicine reduces arterial stiffness in patients with Familial Mediterranean Fever and patients with coronary artery disease. Pathophysiological mechanisms underlying the cardioprotective effect of these drugs may be related to interactions between the cytoskeleton, TOR signaling and cyclic AMP synthesis that remain to be fully elucidated. Adult vascular smooth muscle cells exhibit a contractile phenotype and produce little extracellular matrix. Conditions that upregulate extracellular matrix synthesis induce a phenotypic switch toward a synthetic phenotype. TOR inhibition with rapamycin reduces extracellular matrix production by promoting the change to the contractile phenotype. Cilostazol increases the cytosolic level of cyclic AMP, which in turn leads to a reduction in extracellular matrix synthesis. Colchicine is a microtubule-destabilizing agent that may enhance the synthesis of cyclic AMP.

Arterial Stiffness in the Heart Disease of CKD

CKD frequently leads to chronic cardiac dysfunction. This complex relationship has been termed as cardiorenal syndrome type 4 or cardio-renal link. Despite numerous studies and reviews focused on the pathophysiology and therapy of this syndrome, the role of arterial stiffness has been frequently overlooked. In this regard, several pathogenic factors, including uremic toxins (i.e., uric acid, phosphates, endothelin-1, advanced glycation end-products, and asymmetric dimethylarginine), can be involved. Their effect on the arterial wall, direct or mediated by chronic inflammation and oxidative stress, results in arterial stiffening and decreased vascular compliance. The increase in aortic stiffness results in increased cardiac workload and reduced coronary artery perfusion pressure that, in turn, may lead to microvascular cardiac ischemia. Conversely, reduced arterial stiffness has been associated with increased survival. Several approaches can be considered to reduce vascular stiffness and improve vascular function in patients with CKD. This review primarily discusses current understanding of the mechanisms concerning uremic toxins, arterial stiffening, and impaired cardiac function, and the therapeutic options to reduce arterial stiffness in patients with CKD.

Improved Pulse Wave Velocity and Renal Function in Individualized Calcineurin Inhibitor Treatment by Immunomonitoring: The Randomized Controlled Calcineurin Inhibitor-Sparing Trial

BACKGROUND

A new immune monitoring tool which assesses the expression of nuclear factor of activated T cells (NFAT)-regulated genes measures the functional effects of cyclosporine A. This is the first prospective randomized controlled study to compare standard pharmacokinetic monitoring by cyclosporine trough levels to NFAT-regulated gene expression (NFAT-RE).

METHODS

Expression of the NFAT-regulated genes was determined by qRT-PCR at cyclosporine trough and peak level. Cardiovascular risk was assessed by change of pulse wave velocity from baseline to month 6. Clinical follow-up was 12 months.

RESULTS

In total, 55 stable kidney allograft recipients were enrolled. Mean baseline residual NFAT-RE was 13.1 ± 9.1%. Patients in the NFAT-RE group showed a significant decline in pulse wave velocity from baseline to month 6 versus the standard group (-1.7 ± 2.0 m/s vs 0.4 ± 1.4 m/s, P < 0.001). Infections occurred more often in the standard group compared with the immune monitoring group. No opportunistic infections occurred with NFAT-RE monitoring. At 12 months of follow-up, renal function was significantly better with NFAT-RE versus standard monitoring (Nankivell glomerular filtration rate: 68.5 ± 17.4 mL/min vs 57.2 ± 19.0 mL/min; P = 0.009).

CONCLUSIONS

NFAT-RE as translational immune monitoring tool proved efficacious and safe in individualizing cyclosporine therapy, with the opportunity to reduce the cardiovascular risk and improve long-term renal allograft function.

Association Between Renal Dysfunction and Major Adverse Cardiac Events After Liver Transplantation: Evidence from an International Randomized Trial of Everolimus-Based Immunosuppression

Background

Prospective evidence is lacking regarding the association between renal dysfunction and cardiovascular events after liver transplantation.

Material/Methods

Data were analyzed post hoc regarding renal function and major adverse cardiac events in a two-year prospective trial of de novo liver transplant recipients randomized at 30 days post-transplant to (i) everolimus [EVR]/reduced tacrolimus [EVR/rTAC] (ii) EVR with tacrolimus discontinued [TAC Elimination] or (iii) standard tacrolimus [TAC Control].

Results

By month 24 post-transplant, 32/716 patients had experienced a first major cardiac event (4.5%): 4.1% (10/245), 2.2% (5/229) and 7.0% (17/242) of patients in the EVR/rTAC, TAC Elimination and TAC Control groups, respectively (p=0.043). The cumulative eGFR area under the curve (AUC) from randomization to month 24 was 119 706, 123 082, and 105 946 mL in the EVR/rTAC, TAC Elimination, and TAC Control groups, respectively, corresponding to a mean eGFR AUC of 82.4, 83.0, and 71.9 mL/min/1.73 m². Cox regression modeling showed that mean eGFR AUC was inversely associated with time to first major cardiac event: the hazard ratio per mL/min/1.73 m² was −0.0000015 [95% CI −0.00000078; −0.0000024] (p<0.001).

Conclusions

These findings confirm retrospective evidence that the risk of major cardiac events increases with deteriorating renal function after liver transplantation and demonstrate the need for careful cardiovascular risk management in patients with renal impairment. Immunosuppression based on everolimus with tacrolimus withdrawal, or to a lesser extent tacrolimus reduction, improves both renal function and the risk of major cardiac events compared to standard tacrolimus therapy in liver transplant recipients.

Cyclosporin A Aggravates Calcification of Vascular Smooth Muscle Cells Under High-Glucose Conditions with a Calcifying Medium

BACKGROUND Vascular calcification (VC) progresses substantially even after kidney transplantation, and is a predictor of morbidity and mortality. However, the effect of cyclosporin A (CsA) on VC has not been reported in diabetic kidney transplant patients. In this study, we evaluated the effect of CsA on the VC of mouse vascular smooth muscle cells (VSMCs) under high glucose (HG). MATERIAL AND METHODS To demonstrate the effect of CsA (1.0 µmol/L) and HG (30 mM) in the induction of the VC of the VSMCs, we determined alkaline phosphatase (ALP) activity, microscopic morphology of calcification, the expressions of the calcification and inflammation-related genes, and the intracellular calcium concentrations in VSMCs. RESULTS Calcification was observed 14 days after exposure to a calcifying medium (sodium phosphate monobasic and dibasic mixture). On microscopic morphology, CsA alone did not induce calcification under HG conditions, but clearly increased calcification under HG with a calcifying medium. ALP activity increased under HG with CsA or a calcifying medium compared to HG conditions alone. CsA increased ALP activity under low glucose (LG, 5.5 mM) with a calcifying medium, but markedly increased under HG with a calcifying medium. CsA significantly increased the mRNA expressions of the calcification markers (core binding factor-alpha 1, bone morphologic proteins 2) as well as those of the inflammatory marker (interleukin 6), under HG with a calcifying medium. Intracellular calcium concentrations were unchanged in CsA alone but significantly increased with the presence of a calcifying medium under both LG and HG conditions. CONCLUSIONS Considering the effect of CsA on VC, the vascular adverse effects of CsA need to be verified in diabetic transplant patients in the future.

Impact of immunosuppressive therapy on arterial stiffness in kidney transplantation: are all treatments the same?

Arterial stiffness is a biologic process related to ageing and its relationship with cardiovascular risk is well established. Several methods are currently available for non-invasive measurement of arterial stiffness that provide valuable information to further assess patients’ vascular status in real time. In kidney transplantation recipients, several factors could accelerate the stiffness process, such as the use of calcineurin inhibitors (CNIs), the presence of chronic kidney disease and other classical cardiovascular factors, which would explain, at least in part, the high cardiovascular mortality and morbidity. Despite the importance of arterial stiffness as a biomarker of cardiovascular risk, and unlike other cardiovascular risk factors (e.g. left ventricular hypertrophy), only a few clinical trials or retrospective studies of kidney recipients have evaluated its impact. In this review we describe the clinical impact of arterial stiffness as a prognostic marker of cardiovascular disease and the effects of different immunosuppressive regimens on its progression, focusing on the potential benefits of CNI-sparing protocols and supporting the rationale for individualization of immunosuppression in patients with lower arterial elasticity. Among the immunosuppressive drugs, a belatacept-based regimen seems to offer better vascular protection compared with CNIs, although further studies are needed to confirm the preliminary positive results.

Cardiovascular Parameters to 2 years After Kidney Transplantation Following Early Switch to Everolimus Without Calcineurin Inhibitor Therapy: An Analysis of the Randomized ELEVATE Study

BACKGROUND

Mammalian target of rapamycin inhibitors may confer cardioprotective advantages, but clinical data are limited.

METHODS

In the open-label ELEVATE trial, kidney transplant patients were randomized at 10 to 14 weeks after transplant to convert from calcineurin inhibitor (CNI) to everolimus or remain on standard CNI therapy. Prespecified end points included left ventricular mass index and, in a subpopulation of patients, arterial stiffness as measured by pulse wave velocity.

RESULTS

The mean change in left ventricular mass index from randomization was similar with everolimus versus CNI (month 24, -4.37 g/m versus -5.26 g/m; mean difference, 0.89 [p = 0.392]). At month 24, left ventricular hypertrophy was present in 41.7% versus 37.7% of everolimus and CNI patients, respectively. Mean pulse wave velocity remained stable with both everolimus (mean change from randomization to month 12, -0.24 m/s; month 24, -0.03 m/s) and CNI (month 12, 0.11 m/s; month 24, 0.16 m/s). The change in mean ambulatory nighttime blood pressure from randomization showed a benefit for diastolic pressure at month 12 (P = 0.039) but not at month 24. Major adverse cardiac events occurred in 1.1% and 4.2% of everolimus-treated and CNI-treated patients, respectively, by month 12 (P = 0.018) and 2.3% (8/353) and 4.5% by month 24 (P = 0.145).

CONCLUSIONS

Overall, these data do not suggest a clinically relevant effect on cardiac end points after early conversion from CNI to a CNI-free everolimus-based regimen.

Early Conversion From Calcineurin Inhibitor- to Everolimus-Based Therapy Following Kidney Transplantation: Results of the Randomized ELEVATE Trial

In a 24-month, multicenter, open-label, randomized trial, 715 de novo kidney transplant recipients were randomized at 10-14 weeks to convert to everolimus (n = 359) or remain on standard calcineurin inhibitor (CNI) therapy (n = 356; 231 tacrolimus; 125 cyclosporine), all with mycophenolic acid and steroids. The primary endpoint, change in estimated glomerular filtration rate (eGFR) from randomization to month 12, was similar for everolimus versus CNI: mean (standard error) 0.3(1.5) mL/min/1.73² versus -1.5(1.5) mL/min/1.73² (p = 0.116). Biopsy-proven acute rejection (BPAR) at month 12 was more frequent under everolimus versus CNI overall (9.7% vs. 4.8%, p = 0.014) and versus tacrolimus-treated patients (2.6%, p < 0.001) but similar to cyclosporine-treated patients (8.8%, p = 0.755). Reporting on de novo donor-specific antibodies (DSA) was limited but suggested more frequent anti-HLA Class I DSA under everolimus. Change in left ventricular mass index was similar. Discontinuation due to adverse events was more frequent with everolimus (23.6%) versus CNI (8.4%). In conclusion, conversion to everolimus at 10-14 weeks posttransplant was associated with renal function similar to that with standard therapy overall. Rates of BPAR were low in all groups, but lower with tacrolimus than everolimus.

Impact of early conversion from cyclosporin to everolimus on left ventricular mass index: A randomized controlled trial

This is an 18-month prospective, randomized controlled trial (RCT) designed to compare the effect of early conversion from cyclosporin to everolimus/mycophenolic acid (E-MPA) between 3 and 4 months post-transplant to cyclosporin/mycophenolic acid (CsA-MPA) on left ventricular mass index (LVMI) at 3 and 18 months post-transplant (primary outcome). Secondary outcomes included estimated glomerular filtration rate (eGFR), viral infection, and adverse events. Twenty-four patients were randomized in a 1:1 ratio to E-MPA or CsA-MPA groups. There were no significant differences in mean (SD) LVMI at 3 (51.6±18.5 vs 53.7±15.7 g/m^2.7 ) and 18 months (52.7±16.3 vs 51.7±16.8 g/m^2.7 ) between CsA-MPA and E-MPA groups. The incidence of viral infections was reduced in E-MPA compared to CsA-MPA treatment groups (8% vs 50%, P=.02), but the incidences of acute rejection, adverse events, and drug discontinuation were similar between groups. There was an overall increase in eGFR with time (0.04 log- mL/min/1.73 m² per 6 months, P=.012) but no significant difference between the two groups across time (0.11 log- mL/min/1.73 m² , P=.311). Immunosuppressive regimen comprising early conversion from cyclosporine to everolimus was not associated with a regression of LVMI, but a lower risk of viral infections was observed.

Effect of Immunosuppressive Treatment on Carotid Atherosclerosis in Renal Transplant Recipients

BACKGROUND

The aim of this study was to compare the effect of immunosuppressive regimens using either mammalian target of rapamycin inhibitors (mTORi) or calcineurin inhibitors (CNI) on the risk of atherosclerosis in renal transplant patients.

MATERIALS AND METHODS

The study involved a group of 24 recipients treated with mTORi (mTORi group) and a group of 20 recipients treated with immunosuppressive regimen based on CNI (CNI group). Laboratory and clinical markers of cardiovascular risk in both groups were investigated. Carotid atherosclerosis was evaluated by measurement of the intima media thickness (IMT) of the common and internal carotid artery walls and detection of carotid plaques by a high-resolution ultrasonography. The study was performed 3-24 years after transplantation.

RESULTS

The mTORi group showed higher level of total cholesterol (242 vs 201 mg/dL; P < .004), low-density lipoprotein cholesterol (140 vs 116 mg/dL; P < .05), and triglycerides (226 vs 168 mg/dL; P < .01). Posttransplant diabetes developed in 34% of mTORi group compared with 25% in the CNI group. The mean of IMT (left and right) of common and internal carotid arteries was similar in both groups. Carotid plaques were detected in 46% of patients from the mTORi group and 25% from CNI group (P < .02). The presence of carotid plaques combined with an IMT of >0.9 mm were associated with male gender, mTORi treatment (P = .03), and cardiovascular events. The incidence of coronary heart disease was higher in mTORi group than in CNI group (53% vs 20%; P = .03).

CONCLUSIONS

There was not beneficial effect of immunosuppressive treatment with mTORi on carotid atherosclerosis in renal transplant patients.

Efficacy and Safety of Everolimus for Maintenance Immunosuppression of Kidney Transplantation: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Conversion to everolimus is often used in kidney transplantation to overcome calcineurin inhibitor (CNI) nephrotoxicity but there is conflicting evidence for this approach.

OBJECTIVES

To investigate the benefits and harm from randomized clinical trials (RCTs) involving the conversion from CNI to everolimus after kidney transplantation.

METHODS

Databases were searched up to March 2016. Two reviewers independently assessed trials for eligibility and quality, and extracted data. Results are expressed as risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI).

RESULTS

Eleven RCTs, with a total of 1,633 patients, met the final inclusion criteria. Patients converted to everolimus had improved renal function at 1 year posttransplant with an estimated glomerular filtration rate (eGFR) of 5.36 mL/min per 1.73 m2 greater than patients remaining on CNI (p = 0.0005) and the longer-term results (> 1 year) of renal function was identical to that of 1 year. There was not a substantial difference in graft loss, mortality, and the occurrence of adverse events (AEs) or serious AEs. However, the risks of acute rejection and trial termination due to AEs with everolimus are respectively 1.82 and 2.63 times greater than patients staying on CNI at 1 year posttransplant (p = 0.02, p = 0.03, respectively). Further, those patients who converted to everolimus had a substantially greater risk of anemia, hyperlipidemia, hypercholesterolemia, hypokalemia, proteinuria, stomatitis, mouth ulceration, and acne.

CONCLUSIONS

Conversion from CNI to everolimus after kidney transplantation is associated with improved renal function in the first 5 years posttransplant but increases the risk of acute rejection at 1 year posttransplant and may not be well endured.

A longitudinal study of inflammation, CKD-mineral bone disorder, and carotid atherosclerosis after renal transplantation

BACKGROUND AND OBJECTIVES

The role of reversibility of nontraditional risk factors, like inflammation and CKD-mineral bone disorder, in the reduction of cardiovascular risk after renal transplantation is still scarcely defined.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

The longitudinal relationship between C-reactive protein, CKD-mineral bone disorder biomarkers, and intima media thickness was investigated in a series of 178 patients (age=32±10 years) with stage 5 CKD maintained on chronic dialysis who underwent echo-color Doppler studies of the carotid arteries before and after renal transplantation. Smokers and patients with diabetes were excluded from the study. In all patients, immunosuppression was performed by a standard regimen on the basis of calcineurin inhibitors. Healthy controls were specifically selected to match the age and sex distribution of the patients. Biochemical and intima media thickness assessments were repeated 6 months after transplantation.

RESULTS

Before transplantation, intima media thickness in patients with stage 5 CKD on dialysis (average=0.9±0.2 mm) was higher (P<0.001) than in well matched healthy controls (0.6±0.1 mm) and reduced substantially (-22%; 95% confidence interval, -24% to -20%) after transplantation (P=0.001). GFR (multivariable-adjusted β=0.23; P<0.001), C-reactive protein (β=0.15; P<0.001), and fibroblast growth factor 23 (β=0.28; P<0.001) were the strongest independent correlates of intima media thickness before transplantation. Similarly, longitudinal changes in the same biomarkers were the sole independent correlates of simultaneous changes in intima media thickness (C-reactive protein: β=0.25; fibroblast growth factor 23: β=0.26; P<0.001 for both) after renal transplantation. The evolution of intima media thickness after transplantation was largely independent of classic risk factors, including BP, LDL cholesterol, and insulin resistance, as measured by homeostatic model assessment.

CONCLUSIONS

Intima media thickness improves after renal transplantation. Such an improvement associates with parallel changes in serum C-reactive protein and fibroblast growth factor 23. These observations are in keeping with the hypothesis that the decline in cardiovascular risk after transplantation, in part, depends on partial resolution of nontraditional cardiovascular risk factors, like inflammation and CKD-mineral bone disorder.

The Calcineurin Inhibitor-Sparing (CIS) Trial - individualised calcineurin-inhibitor treatment by immunomonitoring in renal allograft recipients: protocol for a randomised controlled trial

Background

Adequate monitoring tools are required to optimise the immunosuppressive therapy of an individual patient. Particularly, in calcineurin inhibitors, as critical dose drugs with a narrow therapeutic range, the optimal monitoring strategies are discussed in terms of safety and efficacy. Nevertheless, no pharmacokinetic monitoring markers reflect the biological activity of the drug. A new quantitative analysis of gene expression was employed to directly measure the functional effects of calcineurin inhibition: the transcriptional activities of the nuclear factor of activated T-cell (NFAT)-regulated genes in the peripheral blood.

Methods/Design

The CIS study is a randomised prospective controlled trial, comparing a ciclosporin A (CsA)-based immunosuppressive regimen monitored by CsA trough levels to a CsA-based immunosuppressive regimen monitored by residual NFAT-regulated gene expression. Pulse wave velocity as an accepted surrogate marker of the cardiovascular risk is assessed in both study groups. Our hypothesis is that an individualised CsA therapy monitored by residual NFAT-regulated gene expression results in a significantly lower cardiovascular risk compared to CsA therapy monitored by CsA trough levels.

Discussion

There is a lack of evidence in individualising standard immunosuppression in renal allograft recipients. The CIS study will consider the feasibility of individualised ciclosporin A immunosuppression by pharmacodynamic monitoring and evaluate the opportunity to reduce cardiovascular risk while maintaining sufficient immunosuppression.

Trial registration

EudraCT identifier 2011-003547-21, registration date 18 July 2011

https://www.clinicaltrialsregister.eu

A systematic review of conversion from calcineurin inhibitor to mammalian target of rapamycin inhibitors for maintenance immunosuppression in kidney transplant recipients

This was a systematic review of randomized controlled trials comparing delayed conversion of mammalian target of rapamycin inhibitors (mTORi) for calcineurin inhibitors (CNIs) versus CNI continuation in kidney transplantation. Databases (2000-2012) and conference abstracts (2009-2012) were searched giving a total of 29 trials. Outcomes analyzed included GFR, graft loss, rejection and adverse events and were expressed as weighted mean differences (WMDs) or as risk ratios (RRs). Patients converted to mTORi up to 1 year posttransplant in intention-to-treat analysis had higher GFR compared with those remaining on CNI (WMD 0.28 mL/min/1.73 m(2) , 95% confidence interval [CI] 0.21-0.36; I(2)  = 68%, p < 0.001). Stratifying trials by time posttransplant or type of mTORi did not change the overall heterogeneity. For on-treatment population, mTORi was associated with higher GFR (14.21 mL/min/1.73 m(2) , 10.34-18.08; I(2)  = 0%, p = 0.970) 2-5 years posttransplant. The risk of rejection at 1 year was higher in mTORi trials (RR 1.72, 1.34-2.22; I(2)  = 12%, p = 0.330). Discontinuation secondary to adverse events was more common in patients on mTORi, whereas the incidence of skin cancers and cytomegalovirus infection was lower in patients on mTORi. Conversion from CNI to mTORi is associated with short-term improvements in GFR in a number of studies but longer-term follow-up data of graft and patient survival are required.

mTOR inhibitors and dyslipidemia in transplant recipients: a cause for concern?

Post-transplant dyslipidemia is exacerbated by mammalian target of rapamycin (mTOR) inhibitors. Early clinical trials of mTOR inhibitors used fixed dosing with no concomitant reduction in calcineurin inhibitor (CNI) exposure, leading to concerns when consistent and marked dyslipidemia was observed. With use of modern concentration-controlled mTOR inhibitor regimens within CNI-free or reduced-exposure CNI regimens, however, the dyslipidemic effect persists but is less pronounced. Typically, total cholesterol levels are at the upper end of normal, or indicate borderline risk, in kidney and liver transplant recipients, and are lower in heart transplant patients under near-universal statin therapy. Of note, it is possible that mTOR inhibitors may offer a cardioprotective effect. Experimental evidence for delayed progression of atherosclerosis is consistent with evidence from heart transplantation that coronary artery intimal thickening and the incidence of cardiac allograft vasculopathy are reduced with everolimus versus cyclosporine therapy. Preliminary data also indicate that mTOR inhibitors may improve arterial stiffness, a predictor of cardiovascular events, and may reduce ventricular remodeling and decrease left ventricular mass through an anti-fibrotic effect. Post-transplant dyslipidemia under mTOR inhibitor therapy should be monitored and managed closely, but unless unresponsive to therapy should not be regarded as a barrier to its use.

Influence of conversion from calcineurin inhibitors to everolimus on fibrosis, inflammation, tubular damage and vascular function in renal transplant patients

BACKGROUND

Conversion from calcineurin inhibitor (CNI) to mTOR inhibitors may reduce and even halt the progression of chronic allograft dysfunction (CAD) which is the most important cause of renal allograft loss. We aimed to investigate the effects of conversion from CNI to everolimus on parameters of fibrosis, inflammation, glomerulotubular damage and vascular functions in renal transplant recipients.

METHODS

Fifteen stable renal transplant recipients who were under CNI treatment (male/female 13/2, mean age 41 ± 10 years) were enrolled and switched to everolimus. Serum and urinary transforming growth factor-β (TGF-β), urinary neutrophil gelatinase-associated lipocalin (NGAL) and monocyte chemoattractant protein-1 (MCP-1) were measured as markers of fibrosis, tubular damage and inflammation. As parameters of vascular functions, pulse wave velocity (PWV), augmentation index (AIx), serum asymmetric dimethyl-arginine and fibroblast growth factor-23 (FGF-23) were measured. All these measurements were repeated at the 3rd month of conversion.

RESULTS

Estimated GFR (52 ± 7-57 ± 11 ml/min/l.73 m(2), p = 0.02) (was increased after conversion to everolimus. However, serum uric acid levels were significantly decreased (6.21 ± 1.21-5.50 ± 1.39 mg/dL, p = 0.01). Serum TGF-β levels (8727 ± 2897-1943 ± 365 pg/mL, p = 0.03) and urinary NGAL levels (26 ± 10-12 ± 2 ng/mg creatinine, p = 0.05) were significantly decreased. However, urinary MCP-1, FGF-23, PWV and AIx did not change. Urinary TGF-β was associated with urinary NGAL (r = 0.62, p = 0.01), urinary MCP-1 (r = 0.68, p = 0.005) and proteinuria (r = 0.50, p = 0.05).

CONCLUSION

Conversion from CNI to everolimus resulted in significant decreases of serum TGF-β and urinary NGAL which may represent less fibrosis and tubular damage. Association of urinary TGF-β with NGAL and MCP-1 suggests that tubular damage, fibrosis and inflammation may act together for progression of CAD.

Progression of pulse pressure in kidney recipients durably exposed to CsA is a risk factor for epithelial phenotypic changes: an ancillary study of the CONCEPT trial

In this ancillary study of the CONCEPT trial, we studied the role of CsA withdrawal at 3 months (3M) post-transplant on the intensity of epithelial phenotypic changes (EPC, an early marker for kidney fibrogenesis) on the 12 M surveillance biopsy. Although conversion from CsA to sirolimus (SRL) at 3M was reported to have improved mean graft function at 12 M, it did not reduce the score of EPC (1.73 ± 1.15 in the SRL group vs. 1.87 ± 1 in the CsA group, P = 0.61). Acute rejection, which had occurred twice more frequently in SRL-converted patients included here, was associated with 12 M EPC. Interestingly, we observed that the patients durably exposed to CsA and who developed 12 M EPC had a significant progression of blood pulse pressure (pp) from 1 to 6M post-transplantation (Δpp = +12.3 mmHg, P = 0.0035). Pulse pressure at 4, 6, and 9 M and pp progression from 1 to 6M were significantly associated with the development of EPC at 12 M in renal grafts. Logistic regression analysis revealed that a high 6M pp (≥ 60 mmHg) was an independent risk factor for 12 M EPC with an odds ratio of 2.25 per additional 10 mmHg pp (95%CI: 1.14-4.4, P = 0.02) after adjustment with recipient's and donor's age, acute rejection incidence and immunosuppressive regimen. A post hoc analysis of the data collected in the whole population CONCEPT study revealed that pp was significantly higher at 6 months in patients maintained on CsA and that at this time point pp correlated negatively with GFR at 1 year.

Association of a change in immunosuppressive regimen with hemodynamic and inflammatory markers of cardiovascular disease after kidney transplantation

BACKGROUND

Although rejection rates and short-term graft survival have significantly improved in kidney transplantation with the introduction of calcineurin inhibitor (CNI), cardiovascular disease (CVD) and metabolic complications are being increasingly recognized as important causes of morbidity and mortality. We hypothesize that non-CNI proliferation signal inhibitor (PSI)-based immunosuppressive regimen is associated with improved arterial stiffness after kidney transplantation compared with CNI-based immunosuppressive regimens.

METHODS

This is a prospective, single-center study of renal transplant (RT) recipients comparing the metabolic, cardiovascular (pulse wave velocity and aortic augmentation index (AI) adjusted for heart rate (AI × 75)), inflammatory cytokines (interleukins (ILs) 6, 12, and 18) and graft-related outcomes at 3 and 15 months posttransplantation between RT recipients maintained on CNI- (CNI-CNI) or PSI-based (CNI-PSI) regimens including sirolimus and everolimus.

RESULTS

Fifty and 17 RT recipients maintained on CNI-CNI and CNI-PSI, respectively, were included in this study. Median time to PSI conversion from CNI was 5 months. Compared with CNI-CNI recipients, CNI-PSI recipients had significantly lower fasting blood glucose in nondiabetics (coefficient = -16.2; 95% confidence interval (CI) = -14.4 to -18.0; P < 0.01), lower IL-18 levels (coefficient = -229.16; 95% CI = -343.94 to -114.38; P < 0.01), and lower AI × 75 (coefficient = -5.14; 95% CI = -9.99 to -0.28; P = 0.04) at 15 months posttransplant in the multivariable models.

CONCLUSIONS

Our study suggests from the elimination of CNI for PSI may lower AIx75 and IL-18, both surrogate markers of CVD, but adequately powered, randomized, controlled studies are required to establish the causal relationship between immunosuppressive agents and CVD risk.

Conversion to everolimus in kidney transplant recipients: to believe or not believe?

INTRODUCTION

Immunosuppression with calcineurin inhibitors (CNI) in renal transplantation is associated with chronic graft dysfunction, increased cardiovascular risk, and malignancies. Everolimus (EVR) appears to permit a CNI-sparing regimen among stable kidney recipients.

AIM

The aim of this study was to analyze the efficacy and safety of conversion from CNI to EVR.

MATERIAL AND METHODS

This was a retrospective registry-based study of all kidney transplant recipients converted from CNI to EVR between 2006 and 2010. One hundred fifty-one patients, including 69.5% males and with an overall mean age of 50.2 ± 12.7 years, underwent conversion to EVR at 37.0 ± 49.8 (16) months after transplantation with 33.7% during the first 6 months. Reasons for conversion included: CNI nephrotoxicity prevention (54.3%), chronic graft dysfunction (25.8%), malignant tumors (10.6%), CNI-adverse reactions (6.6%), and biopsy-proven CNI nephrotoxicity (2.6%). During a follow-up of 17.9 ± 9.9 months (range, 6-58.5), 18 patients (11.9%) were reconverted to CNI, 2 died with functioning grafts, and 2 lost kidney function.

RESULTS

We observed a significant (P < .001) increase in estimated glomerular filtration rate-Modification of Diet in Renal Disease (eGFR-MDRD) by 11.3% within 6 months: 56.7 ± 22.1 to 64.1 ± 23.4 mL/min/1.73 m(2). At final evaluation it was 13.7%, namely, to 65.5 ± 23.0 mL/min/1.73 m(2). At the end of follow-up the proportion of patients with >300 mg/d proteinuria increased from 7.9% to 23.3% (P = .001). Dyslipidemia prevalence increased from 69.5% to 77.5% (P = not significant [NS]) and arterial hypertension increased from 49% to 65.9% (P < .001) at the end of follow-up. Other reported side effects included oral ulcers (2.6%), edema (5.3%), interstitial pneumonitis (1.3%), and toxic hepatitis (1.3%), some of them leading to EVR discontinuation.

CONCLUSION

In our population, renal function improved significantly after conversion from CNI to EVR. Although side effects were common, most were mild, withdrawal of EVR was necessary in a low percentage of cases. EVR appears to be an effective, safe alternative to CNI for maintenance therapy in selected kidney transplant recipients.

Mechanistic target of rapamycin inhibitors in solid organ transplantation: from benchside to clinical use

PURPOSE OF REVIEW

Here, we review recent advances and new insights in mechanistic target of rapamycin (mTOR) biology (signalling pathway, kidney biology and immune system), and recent clinical data on mTOR inhibitors related to solid organ transplantation.

RECENT FINDINGS

The mTOR pathway is a major integrator of signals governing protein and lipid biosynthesis and growth factor-driven cell cycle progression. Recent findings have emphasized a critical role of mTOR in cellular homeostasis with a crucial role in podocyte function. Beyond CD8(+) and regulatory T-cell control, mTOR protein is involved in critical biological functions of T helper cells or dendritic cells. New specific inhibitors of mTORC1/C2 are available and shed new light on mTOR functions. Finally, clinical trials have better defined the use of mTOR inhibitors and emphasized their role in cancer prevention.

SUMMARY

The mTOR pathway is considered as a key integrator of multiple inputs that drives numerous biological processes in cell biology. mTOR inhibitors are potent immunosuppressive drugs for solid organ transplantation. Newly designed specific inhibitors of mTOR complex 1 and 2 offer promising therapeutic effects and a better understanding of the pathway. Many conditions may benefit from mTOR inhibition for a short period, but tolerance of treatment in a chronic setting remains a major concern.

Immunosuppressant regimen based on sirolimus decreases aortic stiffness in renal transplant recipients in comparison to cyclosporine

Whether or not a cyclosporine A (CsA)-free immunosuppressant regimen based on sirolimus (SRL) prevents aortic stiffening and improves central hemodynamics in renal recipients remains unknown. Forty-four patients (48 ± 2 years) enrolled in the CONCEPT trial were randomized at week 12 (W12) to continue CsA or switch to SRL, both associated with mycophenolate mofetil. Carotid systolic blood pressure (cSBP), pulse pressure (cPP), central pressure wave reflection (augmentation index, AIx) and carotid-to-femoral pulse-wave velocity (PWV: aortic stiffness) were blindly assessed at W12, W26 and W52 together with plasma endothelin-1 (ET-1), thiobarbituric acid-reactive substances (TBARS) and superoxide dismutase (SOD) and catalase erythrocyte activities. At W12, there was no difference between groups. At follow-up, PWV, cSBP, cPP and AIx were lower in the SRL group. The difference in PWV remained significant after adjustment for blood pressure and eGFR. In parallel, ET-1 decreased in the SRL group, while TBARS, SOD and catalase erythrocyte activities increased in both groups but to a lesser extent in the SRL group. Our results demonstrate that a CsA-free regimen based on SRL reduces aortic stiffness, plasma endothelin-1 and oxidative stress in renal recipients suggesting a protective effect on the arterial wall that may be translated into cardiovascular risk reduction.

The relation between hypomagnesaemia and vascular stiffness in renal transplant recipients

BACKGROUND

Arterial stiffness is a strong predictor of outcome. Hypomagnesaemia, by its association with arterial hypertension, endothelial dysfunction, dyslipidaemia and inflammation, might affect vascular stiffness. As hypomagnesaemia is common in renal transplant recipients (RTR), we examined its potential association with arterial stiffness.

METHODS

Cross-sectional analysis. Evaluation of vascular stiffness in 512 RTR from two university centres at a median of 72 months post-transplantation. Determination of carotid-femoral pulse wave velocity (PWV) (SphygmoCor). A multiple linear regression analysis was used to investigate the independent relationship between magnesium serum level and PWV with the following covariates: age, diabetes, smoking status, body mass index, blood pressure, heart rate (HR), C-reactive protein (CRP), high-density lipoprotein cholesterol, parathyroid hormone and use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, diuretics, calcium channel blockers, statins and calcineurin inhibitors next to their drug levels.

RESULTS

Lower serum magnesium was independently associated with PWV (P = 0.018) in addition to age, CRP, HR, diabetes and mean arterial pressure (model R(2) = 0.45; P < 0.001). The relationship between magnesium and PWV was attenuated (P = 0.054) after adjustment for the use of sirolimus, which was associated with higher magnesium levels (P<0.001) and lower PWV (P = 0.013). In patients >55 years (median age), however (low), magnesium remained an independent predictor of PWV (P = 0.024) after accounting for the same covariates.

CONCLUSIONS

Serum magnesium is an independent predictor of arterial stiffness in RTR, especially in patients >55 years.

Asymmetrical dimethylarginine is associated with renal and cardiovascular outcomes and all-cause mortality in renal transplant recipients

Increased plasma levels of asymmetric dimethylarginine (ADMA) are associated with endothelial dysfunction and predict the progression to dialysis and death in patients with chronic kidney disease. The effects of these increased ADMA levels in renal transplant recipients, however, are unknown. We used the data from ALERT, a randomized, double-blind, placebo-controlled study of the effect of fluvastatin on cardiovascular and renal outcomes in 2102 renal transplant recipients with stable graft function on enrollment. Patients who were initially randomized to fluvastatin or placebo in the 5- to 6-year trial were offered open-label fluvastatin in a 2-year extension of the original study. After adjustment for baseline values for established factors in this post hoc analysis, ADMA was found to be a significant risk factor for graft failure or doubling of serum creatinine (hazard ratio 2.78), major cardiac events (hazard ratio 2.61), cerebrovascular events (hazard ratio 6.63), and all-cause mortality (hazard ratio 4.87). In this trial extension, the number of end points increased with increasing quartiles of plasma ADMA levels. All end points were significantly increased in the fourth compared to the first quartile. Our study shows that elevated plasma levels of ADMA are associated with increased morbidity, mortality, and the deterioration of graft function in renal transplant recipients.