Targeted and global pharmacometabolomics in everolimus-based immunosuppression: association of co-medication and lysophosphatidylcholines with dose requirement.

INTRODUCTION: The immunosuppressive therapy with everolimus (ERL) after heart transplantation is characterized by a narrow therapeutic window and a substantial variability in dose requirement. Factors explaining this variability are largely unknown. OBJECTIVES: Our aim was to evaluate factors affecting ERL metabolism and to identify novel metabolites associated with the individual ERL dose requirement to elucidate mechanisms underlying ERL dose response variability. METHOD: We used liquid chromatography coupled with mass spectrometry for quantification of ERL metabolites in 41 heart transplant patients and evaluated the effect of clinical and genetic factors on ERL pharmacokinetics. Non-targeted plasma metabolic profiling by ultra-performance liquid chromatography and high resolution quadrupole-time-of-flight mass spectrometry was used to identify novel metabolites associated with ERL dose requirement. RESULTS: The determination of ERL metabolites revealed differences in metabolite patterns that were independent from clinical or genetic factors. Whereas higher ERL dose requirement was associated with co-administration of sodium-mycophenolic acid and the CYP3A5 expressor genotype, lower dose was required for patients receiving vitamin K antagonists. Global metabolic profiling revealed several novel metabolites associated with ERL dose requirement. One of them was identified as lysophosphatidylcholine (lysoPC) (16:0/0:0). Subsequent targeted analysis revealed that high levels of several lysoPCs were significantly associated with higher ERL dose requirement. CONCLUSION: For the first time, this study describes distinct ERL metabolite patterns in heart transplant patients and detected potentially new drug-drug interactions. The global metabolic profiling facilitated the discovery of novel metabolites associated with ERL dose requirement that might represent new clinically valuable biomarkers to guide ERL therapy.

Influence of CYP3A5 genetic variation on everolimus maintenance dosing after cardiac transplantation.

BACKGROUND: Everolimus (ERL) has become an alternative to calcineurin inhibitors (CNIs) due to its renal-sparing properties, especially in heart transplant (HTx) recipients with kidney dysfunction. However, ERL dosing is challenging due to its narrow therapeutic window combined with high interindividual pharmacokinetic variability. Our aim was to evaluate the effect of clinical and genetic factors on ERL dosing in a pilot cohort of 37 HTx recipients. METHODS: Variants in CYP3A5, CYP3A4, CYP2C8, POR, NR1I2, and ABCB1 were genotyped, and clinical data were retrieved from patient charts. RESULTS: While ERL trough concentration (C0 ) was within the targeted range for most patients, over 30-fold variability in the dose-adjusted ERL C0 was observed. Regression analysis revealed a significant effect of the non-functional CYP3A5*3 variant on the dose-adjusted ERL C0 (p = 0.031). ERL dose requirement was 0.02 mg/kg/d higher in patients with CYP3A5*1/*3 genotype compared to patients with CYP3A5*3/*3 to reach the targeted C0 (p = 0.041). ERL therapy substantially improved estimated glomerular filtration rate (28.6 ± 6.6 mL/min/1.73 m(2)) in patients with baseline kidney dysfunction. CONCLUSION: Everolimus pharmacokinetics in HTx recipients is highly variable. Our preliminary data on patients on a CNI-free therapy regimen suggest that CYP3A5 genetic variation may contribute to this variability.

Cytomegalovirus infection and disease reduce 10-year cardiac allograft vasculopathy-free survival in heart transplant recipients.

BACKGROUND: Cytomegalovirus (CMV) is associated with an increased risk of cardiac allograft vasculopathy (CAV), the major limiting factor for long-term survival after heart transplantation (HTx). The purpose of this study was to evaluate the impact of CMV infection during long-term follow-up after HTx. METHODS: A retrospective, single-centre study analyzed 226 HTx recipients (mean age 45 ± 13 years, 78 % men) who underwent transplantation between January 1988 and December 2000. The incidence and risk factors for CMV infection during the first year after transplantation were studied. Risk factors for CAV were included in an analyses of CAV-free survival within 10 years post-transplant. The effect of CMV infection on the grade of CAV was analyzed. RESULTS: Survival to 10 years post-transplant was higher in patients with no CMV infection (69 %) compared with patients with CMV disease (55 %; p = 0.018) or asymptomatic CMV infection (54 %; p = 0.053). CAV-free survival time was higher in patients with no CMV infection (6.7 years; 95 % CI, 6.0-7.4) compared with CMV disease (4.2 years; CI, 3.2-5.2; p < 0.001) or asymptomatic CMV infection (5.4 years; CI, 4.3-6.4; p = 0.013). In univariate analysis, recipient age, donor age, coronary artery disease (CAD), asymptomatic CMV infection and CMV disease were significantly associated with CAV-free survival. In multivariate regression analysis, CMV disease, asymptomatic CMV infection, CAD and donor age remained independent predictors of CAV-free survival at 10 years post-transplant. CONCLUSIONS: CAV-free survival was significantly reduced in patients with CMV disease and asymptomatic CMV infection compared to patients without CMV infection. These findings highlight the importance of close monitoring of CMV viral load and appropriate therapeutic strategies for preventing asymptomatic CMV infection.

CYP3A5*3 and POR*28 genetic variants influence the required dose of tacrolimus in heart transplant recipients.

BACKGROUND: After heart transplantation (HTx), the interindividual pharmacokinetic variability of immunosuppressive drugs represents a major therapeutic challenge due to the narrow therapeutic window between over-immunosuppression causing toxicity and under-immunosuppression leading to graft rejection. Although genetic polymorphisms have been shown to influence pharmacokinetics of immunosuppressants, data in the context of HTx are scarce. We thus assessed the role of genetic variation in CYP3A4, CYP3A5, POR, NR1I2, and ABCB1 acting jointly in immunosuppressive drug pathways in tacrolimus (TAC) and ciclosporin (CSA) dose requirement in HTx recipients. METHODS: Associations between 7 functional genetic variants and blood dose-adjusted trough (C0) concentrations of TAC and CSA at 1, 3, 6, and 12 months after HTx were evaluated in cohorts of 52 and 45 patients, respectively. RESULTS: Compared with CYP3A5 nonexpressors (*3/*3 genotype), CYP3A5 expressors (*1/*3 or *1/*1 genotype) required around 2.2- to 2.6-fold higher daily TAC doses to reach the targeted C0 concentration at all studied time points (P ≤ 0.003). Additionally, the POR*28 variant carriers showed higher dose-adjusted TAC-C0 concentrations at all time points resulting in significant differences at 3 (P = 0.025) and 6 months (P = 0.047) after HTx. No significant associations were observed between the genetic variants and the CSA dose requirement. CONCLUSIONS: The CYP3A5*3 variant has a major influence on the required TAC dose in HTx recipients, whereas the POR*28 may additionally contribute to the observed variability. These results support the importance of genetic markers in TAC dose optimization after HTx.

Heart rate kinetics during standard cardiopulmonary exercise testing in heart transplant recipients: a longitudinal study.

AIMS: Heart transplantation (HTx) results in complete autonomic denervation of the donor heart, causing resting tachycardia and abnormal heart rate (HR) responses to exercise. We determined the time course of suggestive cardiac reinnervation post HTx and investigated its clinical significance. METHODS AND RESULTS: Heart rate kinetics during standard cardiopulmonary exercise testing at 2.5-5 years after HTx was assessed in 58 patients. According to their HR increase 30 s after exercise onset, HTx recipients were classified as denervated (slow responders: <5 beats per minute [b.p.m.]) or potentially reinnervated (fast responders: ≥5 b.p.m.). Additionally, in 30 patients, longitudinal changes of maximal oxygen consumption and HR kinetics were assessed during the first 15 post-operative years. At 2.5-5 years post HTx, 38% of our study population was potentially reinnervated. Fast responders were significantly younger (41 ± 15 years) than slow responders (53 ± 13 years, P = 0.003) but did not differ with regard to donor age, immunosuppressive regime, cardiovascular risk factors, endomyocardial biopsy, or vasculopathy parameters. While HR reserve (56 ± 20 vs. 39 ± 15 b.p.m., P = 0.002) and HR recovery after 60 s (15 ± 11 vs. 5 ± 6 b.p.m., P < 0.001) were greater in fast responders, resting HR, peak HR of predicted, and peak oxygen consumption of predicted were comparable. CONCLUSIONS: Signs of reinnervation occurred mainly in younger patients. Maximal oxygen consumption was independent of HR kinetics.

Progression of cardiac allograft vasculopathy assessed by serial three-vessel quantitative coronary angiography.

BACKGROUND: The purpose of the present study was to assess the short- and long-term progression of cardiac allograft vasculopathy (CAV) using serial 3-vessel quantitative coronary angiography (QCA). METHODS: CAV progression was assessed using serial 3-vessel QCA analysis at baseline, 1-year and long-term angiographic follow-up (8.5±3.7 years) after heart transplantation. The change in minimal lumen diameter (MLD) and percent diameter stenosis (%DS) was serially assessed within matched segments. Patients were graded according to the ISHLT-CAV classification and grouped as ISHLT-CAV0 and ISHLT-CAV1-3. The primary endpoint was mean change in MLD and %DS. RESULTS: A total of 41 patients and 520 matched segments were available for serial 3-vessel QCA. Overall, MLD decreased non-significantly from baseline to 1-year follow-up and significantly from 1-year to the long-term angiographic follow-up (Δ-0.08mm/year [95%CI -0.11 to -0.05], P<0.001). %DS increased significantly from baseline to 1-year (Δ+0.96%/year [95%CI 0.04 to 1.88], P = 0.041) and from 1-year to long-term angiographic follow-up (Δ+0.61%/year [95%CI 0.33 to 0.88], P<0.001). ISHLT-CAV1-3 at 1 year and at long-term angiographic follow-up was observed in 22% and 61%, respectively. Between baseline and long-term angiographic follow-up, a significant reduction in MLD was observed within both groups without a significant difference in the reduction between the two groups (ISHLT-CAV0: median -0.49mm [IQR -0.54 to -0.43] vs. ISHLT-CAV1-3: median -0.40mm [IQR -0.44 to -0.35], P = 0.4). CONCLUSION: The current data suggest that QCA can't predict CAV beyond 1 year, but, QCA affirmed that CAV progresses to a similar extent in patients who do not develop visual CAV during long-term follow-up.

Circulating oxidized low-density lipoprotein is associated with echolucent plaques in the femoral artery independently of hsCRP in 61-year-old men.

OBJECTIVES: The aim of the study was to test the hypothesis that circulating markers of inflammation (high-sensitive C-reactive protein, hsCRP) and oxidative modification of lipids (oxidized low-density lipoprotein, oxLDL) were associated with the occurrence of echolucent rather than echogenic femoral artery plaques in a cross-sectional population based cohort of 513, 61-year-old men. BACKGROUND: The relationships between circulating oxLDL, hsCRP and the occurrence of echolucent plaques in the femoral artery have not previously been investigated. METHODS: The levels of circulating oxLDL and hsCRP were determined in plasma by ELISA. Plaque occurrence, size and echogenicity were measured by B-mode ultrasound in the right femoral artery. Assessment of plaque echogenicity was based on the classification (grades 1-4) proposed by Gray-Weale et al. RESULTS: A higher frequency of echolucent femoral plaques was observed in subjects with the metabolic syndrome and current smokers (p=0.01 and p<0.001, respectively) as well as with increasing levels of oxLDL and hsCRP (p=0.002 and p=0.005, respectively). In a multiple logistic regression analysis oxLDL and current smokers turned out to be independent associated with the presence of echolucent femoral artery plaques. CONCLUSIONS: The results of the present study support our hypothesis that circulating oxLDL is a marker of an unstable echolucent plaque phenotype in the femoral artery in man.

Preclinical atherosclerosis and inflammation in 61-year-old men with newly diagnosed diabetes and established diabetes.

OBJECTIVE: The aim of this study was to investigate the occurrence of subclinical atherosclerosis and underlying mechanisms in men with newly diagnosed diabetes and established diabetes compared with healthy control subjects. RESEARCH DESIGN AND METHODS: In a population-based study of 61-year-old Caucasian men (n = 271) with established diabetes (n = 50) and newly diagnosed diabetes (n = 24) and healthy control subjects (n = 197), standard risk factors and highly sensitive (hs) C-reactive protein (CRP) were measured. Ultrasound measurements of intima-media thickness (IMT) were performed bilaterally in the common carotid artery, and a composite measure was calculated from common carotid and carotid bulb IMT (composite IMT). The plaque status was assessed. RESULTS: Composite IMT and carotid plaque size increased gradually among the healthy control subjects, newly diagnosed diabetic patients, and established diabetic patients (P for trend < or =0.001, respectively). CRP was higher in newly and established diabetes (NS between diabetes groups) compared with healthy control subjects (P < 0.001). Total cholesterol levels were lower in newly diagnosed diabetes (5.51 +/- 1.13 mmol/l, P < 0.05) and established diabetes (5.45 +/- 1.15 mmol/l, P < 0.01) compared with those of healthy control subjects (5.77 +/- 1.03 mmol/l). In men with diabetes (n = 74), diabetes onset status (newly diagnosed versus established), waist-to-hip ratio (WHR), and serum triglycerides, but not CRP, explained 16% of the variance in composite IMT. CONCLUSIONS: This is the first study to show increased preclinical atherosclerotic changes (IMT and plaque size) and increased inflammation (hs-CRP) in men with newly diagnosed diabetes as well as in patients with established diabetes compared with healthy control subjects. WHR, diabetes onset status (newly diagnosed versus established), and triglycerides, but not CRP, were independent correlates of carotid artery IMT in men with diabetes.

Plasma NGAL and glomerular filtration rate in cardiac transplant recipients treated with standard or reduced calcineurin inhibitor levels.

AIM: Predictors of renal recovery following conversion from calcineurin inhibitor- to proliferation signal inhibitor-based therapy are lacking. We hypothesized that plasma NGAL (P-NGAL) could predict improvement in glomerular filtration rate (GFR) after conversion to everolimus. PATIENTS & METHODS: P-NGAL was measured in 88 cardiac transplantation patients (median 5 years post-transplant) with renal dysfunction randomized to continuation of conventional calcineurin inhibitor-based immunosuppression or switching to an everolimus-based regimen. RESULTS: P-NGAL correlated with measured GFR (mGFR) at baseline (R(2) = 0.21; p < 0.001). Randomization to everolimus improved mGFR after 1 year (median [25-75 % percentiles]: ΔmGFR 5.5 [-0.5-11.5] vs -1 [-7-4] ml/min/1.73 m(2); p = 0.006). Baseline P-NGAL predicted mGFR after 1 year (R(2) = 0.18; p < 0.001), but this association disappeared after controlling for baseline mGFR. CONCLUSION: P-NGAL and GFR correlate with renal dysfunction in long-term heart transplantation recipients. P-NGAL did not predict improvement of renal function after conversion to everolimus-based immunosuppression.

Everolimus immunosuppression in de novo heart transplant recipients: what does the evidence tell us now?

The efficacy of everolimus with reduced cyclosporine in de novo heart transplant patients has been demonstrated convincingly in randomized studies. Moreover, everolimus-based immunosuppression in de novo heart transplant recipients has been shown in two randomized trials to reduce the increase in maximal intimal thickness based on intravascular ultrasound, indicating attenuation of cardiac allograft vasculopathy (CAV). Randomized trials of everolimus in de novo heart transplantation have also consistently shown reduced cytomegalovirus infection versus antimetabolite therapy. In maintenance heart transplantation, conversion from calcineurin inhibitors to everolimus has demonstrated a sustained improvement in renal function. In de novo patients, a renal benefit may only be achieved if there is an adequate reduction in exposure to calcineurin inhibitor therapy. Delayed introduction of everolimus may be appropriate in patients at high risk of wound healing complications, e.g. diabetic patients or patients with ventricular assist device. The current evidence base suggests that the most convincing reasons for use of everolimus from the time of heart transplantation are to slow the progression of CAV and to lower the risk of cytomegalovirus infection. A regimen of everolimus with reduced-exposure calcineurin inhibitor and steroids in de novo heart transplant patients represents a welcome addition to the therapeutic armamentarium.

Endothelial cell antibody-mediated rejection and successful retransplantation in a heart transplanted patient.

Antibody-mediated rejection (AMR) plays a significant role in cardiac allograft dysfunction, and recently a consensus regarding the diagnosis of AMR has been published. To our knowledge, it has not previously been reported that acute graft failure related to AMR, and antiendothelial cell antibodies can successfully be diagnosed to allow the patient to receive the outlined treatment and undergo a subsequent retransplantation.

Long-term follow-up of lung and heart transplant recipients with pre-transplant malignancies.

BACKGROUND: Concern regarding recurrence of pre-transplant (Tx) malignancy has disqualified patients from Tx. Because this has been poorly studied in lung and heart Tx recipients our aim was to investigate the influence of pre-Tx malignancy on post-Tx recurrence and long-term survival, focusing on pre-operative cancer-free intervals. METHODS: From our lung and heart Tx programs (1983 to 2011) we retrospectively identified 111 (lung, 37; heart, 74) of 3,830 recipients with 113 pre-Tx malignancies. The patients were divided into 3 groups by pre-Tx cancer-free interval: Group I, <12 months (n = 24); Group II, ≥12 to<60 months (n = 18); and Group III, ≥60 months (n = 71). RESULTS: Mean age at pre-Tx malignancy was 35±18 years. Mean post-Tx follow-up time was 70±63 months (range, 0-278 months), and malignancy recurrence was 63% in Group I, 26% in Group II, and 6% in Group III. Kaplan-Meier analysis of freedom from post-Tx recurrence revealed the following differences among the groups: Group I vs II, p = 0.08; II vs III, p = 0.002; and I vs III, p<0.001. Overall survival (51 deaths) was significantly poorer in Group I than in Groups II and III (p = 0.044). Survival between Groups II and III did not differ significantly (p = 0.93). CONCLUSIONS: Cancer-free survival of ≥5 years pre-Tx is associated with the lowest recurrence. However, recurrence is related to the time the patients were cancer-free, as seen in Groups I and II.

Improvement in renal function after everolimus introduction and calcineurin inhibitor reduction in maintenance thoracic transplant recipients: the significance of baseline glomerular filtration rate.

BACKGROUND: The NOCTET (NOrdic Certican Trial in HEart and lung Transplantation) trial demonstrated that everolimus improves renal function in maintenance thoracic transplant (TTx) recipients. Nevertheless, introduction of everolimus is not recommended for patients with advanced renal failure. We evaluated NOCTET data to assess everolimus introduction amongst TTx recipients with advanced renal failure. METHODS: This 12-month multicenter Scandinavian study randomized 282 maintenance TTx recipients to everolimus introduction with calcineurin inhibitor (CNI) reduction or standard CNI therapy. The measured glomerular filtration rate (mGFR) was noted at baseline and after 1-year using Cr-ethylenediaminetetraacetic acid clearance. RESULTS: In 21 patients with a baseline mGFR of 20 to 29 ml/min/1.73 m(2), renal function improved in the everolimus group compared with the control group ((ΔmGFR 6.7 ± 9.0 vs -1.6 ± 5.1 ml/min/1.73 m(2); p = 0.03). Amongst 173 patients with moderate renal impairment (mGFR 30-59 ml/min/1.73 m(2)), renal function improvement was also greater amongst everolimus patients than in controls (ΔmGFR 5.1 ± 11.1 vs -0.5 ± 8.7 ml/min/1.73 m(2); p < 0.01). In 55 patients with mGFR 60 to 89 ml/min/1.73 m(2), mGFR did not change significantly in either group. Improvement in mGFR was limited to patients with a median time since TTx of less than 4.6 years and was also influenced by CNI reduction during the study period. CONCLUSIONS: Everolimus introduction and reduced CNI significantly improved renal function amongst maintenance TTx patients with pre-existing advanced renal failure. This beneficial effect was limited to patients undergoing conversion in less than 5 years after TTx, indicating a window of opportunity that is appropriate for pharmacologic intervention with everolimus.