Ruttens, D., Verleden, S. E., Vandermeulen, E., Bellon, H., Vanaudenaerde, B. M., Somers, J., Schoonis, A., Schaevers, V., Van Raemdonck, D. E., Neyrinck, A., et al
American Journal of Transplantation. 2016;16(1):254-61
Aims:To evaluate the long-term effects of prophylactic azithromycin therapy post lung transplantation in view of the recently updated classification system for chronic lung allograft dysfunction (CLAD).
Interventions:Participants were randomized to receive either azithromycin (250mg) three times per week, or placebo.
Participants:83 single-lung, bilateral lung or heart–lung transplant recipients >18 years of age, previously included in a randomized controlled trial of azithromycin versus placebo*
Outcomes:Outcomes measured were CLAD, graft loss, pulmonary function and functional exercise capacity.
Follow Up:7 years
Mr Simon Knight, Centre for Evidence in Transplantation, The Royal College of Surgeons of England.
This manuscript reports a long-term, retrospective analysis of an RCT comparing prophylactic azithromycin to placebo in lung transplant recipients. Azithromycin has anti-inflammatory and immunomodulatory properties and was shown in an earlier analysis to improve freedom from bronchiolitis obliterans early after lung transplant. Since then, the classification of chronic lung allograft dysfunction (CLAD) has been revised and the authors here
provide a retrospective analysis of the 7-year follow-up of the patients in the trial, using the new CLAD classification. The analysis demonstrates a significant reduction in the incidence of CLAD (and improved CLAD free survival time) with prophylactic azithromycin. Long-term pulmonary function and functional exercise capacity were also significantly better in the treatment arm. Data regarding tacrolimus levels are missing from the manuscript – there are some case reports of interaction between azithromycin and tacrolimus, and erratic tacrolimus levels have been shown to be predictive for development of CLAD. This is a relatively small, retrospective analysis and so should be regarded as exploratory, but nonetheless provides some evidence of a role for prophylactic azithromycin in these patients.
Professor Stuart C. Sweet, Washington University, St. Louis, MO, USA
The article by Ruttens and colleagues provides additional follow-up details 7 years after enrolment of the final patient from a cohort who participated in a randomized, controlled trial of prophylactic azithromycin (AZI) therapy in lung transplant recipients. Using an intention to treat analysis, the original study population was analysed using the updated allograft dysfunction (CLAD) classification. The key
findings of the study included the observation that CLAD-free survival was longer in the azithromycin group, pulmonary function and exercise capacity were better in the azithromycin group (these differences were felt to have developed in the first 2 years of follow-up) and no overall difference in graft survival (felt to be related to the use of open label AZI in both the treatment and placebo groups). No AZI significant side effects were noted. Although this is a single centre study limited by retrospective design of the longer term follow-up, it suggests that centres should consider whether the potential benefit of using AZI prophylaxis in lung transplant recipients may outweigh the potential risks. These findings will benefit from confirmation in a multicentre study, ideally with inclusion of mechanistic analyses.
Azevedo, H., Renesto, P. G., Chinen, R., Naka, E., de Matos, A.C. C., Cenedeze, M. A., Moreira-Filho, C. A., Camara, N. O. S., Pacheco-Silva, A.
Human Genomics. 2016;10(1):2
Aims:To investigate intragraft transcriptional profiles in renal transplant patients with Proximal tubular dysfunction (PTD)
Interventions:Participants were initially treated with cyclosporine (CsA), prednisone and azathioprine. At enrolment, participants were randomized to continue to receive the initial protocol, or an alternative protocol consisting of reduced CsA dosage and mycophenolate mofetil introduction.
Participants:33 renal transplant recipients > 1 year of surgery, diagnosed with PTD according to three consecutive monthly measurements of urinary retinol-binding protein (uRBP) >0.4 mg/L.
Outcomes:The primary outcome measured was transcriptional profiles from paired biopsies at enrolment and 12 months. Other measured outcomes were serum creatine, creatine clearance, and uRBP levels.
Follow Up:12 months
Sir Peter Morris, Centre for Evidence in Transplantation, The Royal College of Surgeons of England.
This is an interesting study based on the assumption that proximal tubular dysfunction is associated with poorer renal graft outcome, for which there is some evidence. Proximal tubular dysfunction was diagnosed in 33 renal transplant patients who were at least one year post-transplant by demonstrating a raised level of the low molecular weight protein (urinary retinal binding protein URBP)
in the urine as an indication of proximal tubular injury. All patients were on cyclosporine, azathioprine and steroids. After randomisation 18 patients had their immunosuppression changed in that cyclosporine dosage was reduced and azathioprine was replaced with mycophenolate. The control group continued on the same immunosuppression. Biopsies were performed at the time of randomisation and again at 12 months, and the follow-up was carried out over 12 months. The alternative immunosuppression scheme did result in better renal function and less evidence of tubular proteinuria at 12 months of follow up, presumably due to the reduction in cyclosporine dose. In their molecular studies they were able to show that there was more evidence of autophagy, extra-cellular matrix and adaptive immunity in the patients who had had modified immunosuppression. They were also able to show the gene expression in a group who remained on the same immunosuppression was related to fibrosis, endocytosis and endoplasmic reticulum stress. The authors suggest that the molecular networks associated with control of endocytosis, autophagy, protein overload, fibrosis and adaptive immunity may be involved in improvement of graft function. This is a carefully done study but small and really underpowered to make a lot of the conclusions valid, but it certainly points the direction for further studies in this area.
Dr Ben Sprangers, Department of Nephrology and Kidney Transplantation, University Hospitals Leuven, Leuven, Belgium
In their article entitled ‘Intragraft transcriptional profiling of renal transplant recipients with tubular dysfunction reveals mechanism underlying graft injury and recovery’ Azevedo et al report the outcome in 33 renal transplant patients with high urinary levels of retinol-binding protein before and after modification of immunosuppressive treatment. Furthermore, they performed paired comparisons of intragraft gene expression profiles by constructing gene co-expression
networks and in doing so identified enriched function and pathways. In total 33 renal transplant patients with high urinary levels of retinol-binding protein (measure of proximal tubular dysfunction) were included in this study and randomized either to a modified immunosuppressive regimen (reduction of cyclosporine dosage and substitution of azathioprine for mycophenolate mofetil, modified IS-group) or to continue their immunosuppression (azathioprine combined with cyclosporine, azathioprine and prednisone). After 12 months of follow up, the patients in the modified IS-group experienced amelioration of kidney function, reduction of urinary retinol-binding proteinuria and reduction of tubular atrophy. Furthermore, there was a marked difference of intragraft gene expression profiles. By performing intragraft transcriptional analysis differentially expressed genes were identified and used to construct co-expression gene networks. Different transcriptional profiles were identified in the modified IS-group (phagosome, antigen processing and presentation, cell adhesion, autoimmunity, allograft rejection, and graft-versus-host disease) compared to the control IS group (endocytosis, ubiquitin-mediated proteolysis, endoplasmic reticulum stress, TGF-β pathway, and adherens junctions). Some points to take into to account when considering results are the following. First of all, only a limited number of patients were included in this study. In total 33 patients were included and randomized to either the modified IS-group (n=18) or control IS-group (n=15). The second aspect to keep in mind is the immunosuppressive regimen which is only being used in developing countries. Third, It is important to note that the difference between the modified IS-group and control IS groups is twofold. In the modified IS-group, both the cyclosporine dosage was diminished and azathioprine was replaced by mycophenolate mofetil. Surprisingly, how reduced and standard CsA dosages are defined is not specified in the paper. Fourth, although interesting, only 25% of the eGFR change in the modified IS-group was explained by the change in the urinary retinol-binding protein (and thus improved tubular function). So important non-tubular function improvement following modification of the IS treatment are present. To me, the technique and data processing and interpretation are most interesting as this is an innovative approach to determine novel involved pathways which should be further studied in the future. I therefore agree with the authors who conclude by stating ‘These results can be useful for further studying the mechanisms underlying graft injury and functional recovery. In particular, the role of genes participating in ubiquitination, autophagy, protein overload, and neuroactive ligand-receptor interaction should be further investigated’.
BACKGROUND Proximal tubular dysfunction (PTD) is associated with a decreased long-term graft survival in renal transplant patients and can be detected by the elevation of urinary tubular proteins. This study investigated transcriptional changes in biopsies from renal transplant patients with PTD to disclose molecular mechanisms underlying graft injury and functional recovery. METHODS Thirty-three renal transplant patients with high urinary levels of retinol-binding protein, a biomarker of PTD, were enrolled in the study. The initial immunosuppressive scheme included azathioprine, cyclosporine, and steroids. After randomization, 18 patients (group 2) had their treatment modified by reducing cyclosporine dosage and substituting azathioprine for mycophenolate mofetil, while the other 15 patients (group 1) remained under the initial scheme. Patients were biopsied at enrollment and after 12 months of follow-up, and paired comparisons were performed between their intragraft gene expression profiles. The differential transcriptome profiles were analyzed by constructing gene co-expression networks and identifying enriched functions and central nodes in each network. RESULTS Only the alternative immunosuppressive scheme used in group 2 ameliorated renal function and tubular proteinuria after 12 months of follow-up. Intragraft molecular changes observed in group 2 were linked to autophagy, extracellular matrix, and adaptive immunity. Conversely, gene expression changes in group 1 were related to fibrosis, endocytosis, ubiquitination, and endoplasmic reticulum stress. CONCLUSION These results suggest that molecular networks associated with the control of endocytosis, autophagy, protein overload, fibrosis, and adaptive immunity may be involved in improvement of graft function.
Andreassen, A. K., Andersson, B., Gustafsson, F., Eiskjaer, H., Radegran, G., Gude, E., Jansson, K., Solbu, D., Karason, K., Arora, S., et al
American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons. 2016;16(4):1238-47
Aims:To provide long term results of the effect of early everolimus initiation with calcineurin inhibitor (CNI) withdrawal on renal function and the rate of cardiac allograft vasculopathy (CAV) progression compared to a conventional CNI-based regimen.
Interventions:Participants were randomized to either, everolimus, low-exposure cyclosporine, mycophenolate mofetil (MMF) and corticosteroids with cyclosporine withdrawal after 7 weeks (everolimus group), versus cyclosporine, MMF and corticosteroids (cyclosporine group).
Participants:115 de novo heart transplant recipients aged 18-70 years
Outcomes:The primary outcome was mean measured glomerular filtration rate (GFR). Other measured outcomes included GFR, estimated GFR, left ventricular function, coronary intravascular ultrasound (IVUS), blood pressure, laboratory data, trough concentrations of everolimus and cyclosporine, concomitant medication and adverse events.
Follow Up:36 months
Mr Simon Knight, Centre for Evidence in Transplantation, The Royal College of Surgeons of England.
This manuscript reports medium-term (36 month) outcomes from the SCHEDULE study, in which de novo cardiac transplant recipients were randomised to a gradual early switch from CNI to everolimus, or continuation of CNI. At 36 months, there was a significantly higher measured GFR in the everolimus group, along with reduced progression of allograft vasculopathy on IVUS in intention-to-treat analysis. These
benefits are seen despite the earlier report of higher rates of acute rejection in the everolimus arm. The study also demonstrated a higher incidence of adverse events during months 12-36 in the everolimus arm. In particular diarrhoea, acne and respiratory tract infections were higher in everolimus-treated recipients. It should also be noted that only around 75% of patients underwent IVUS. Whilst the increased risk of early acute rejection does not appear to affect 3-year allograft vasculopathy or survival, longer-term follow-up will be required to confirm the safety of this regimen.
Dr Christina S. Jenkins, Dr Erin M. Schumer and Dr Mark S. Slaughter, .Department of Cardiovascular and Thoracic Surgery, University of Louisville, USA
Andreassen, et. al. report three year outcomes from the SCHEDULE study, comparing outcomes of de novo cardiac transplant recipients randomized to two separate immunosuppression regimens: everolimus with early calcineurin inhibitor withdrawal (CNI) versus standard CNI therapy. Patients receiving treatment with everolimus had significantly higher mGFR at three years compared to patients undergoing standard CNI therapy, and multivariate analysis demonstrated that
choice of immunosuppression regimen was an independent predictor of mGFR at 3 years. The coronary artery maximal intimal thickness determined by IVUS was also significantly less in the everolimus group, although no significant differences in cardiac allograft vasculopathy were found. Despite these benefits, patients in the everolimus group reported more serious adverse events during the study period and, as previously reported, had higher rates of biopsy-proven acute rejection in the first year after transplant. This study had strict inclusion and exclusion criteria, limiting the generalizability of the study; however, the results suggest that everolimus could benefit patients at high risk for renal compromise following cardiac transplant by limiting progressive renal dysfunction seen with standard immunosuppression with CNI. Use of everolimus may also offer reduction in coronary intimal thickness over time, but the clinical significance of this reduction is unknown. With the higher rate of adverse events in the everolimus arm of the study, long term analysis is needed to determine if the benefit of preserved renal function is maintained beyond three years, and if so, if this benefit outweighs the risk of adverse events in these selected patients
In a randomized, open-label trial, de novo heart transplant recipients were randomized to everolimus (3-6 ng/mL) with reduced-exposure calcineurin inhibitor (CNI; cyclosporine) to weeks 7-11 after transplant, followed by increased everolimus exposure (target 6-10 ng/mL) with cyclosporine withdrawal or standard-exposure cyclosporine. All patients received mycophenolate mofetil and corticosteroids. A total of 110 of 115 patients completed the 12-month study, and 102 attended a follow-up visit at month 36. Mean measured GFR (mGFR) at month 36 was 77.4 mL/min (standard deviation [SD] 20.2 mL/min) versus 59.2 mL/min (SD 17.4 mL/min) in the everolimus and CNI groups, respectively, a difference of 18.3 mL/min (95% CI 11.1-25.6 mL/min; p < 0.001) in the intention to treat population. Multivariate analysis showed treatment to be an independent determinant of mGFR at month 36. Coronary intravascular ultrasound at 36 months revealed significantly reduced progression of allograft vasculopathy in the everolimus group compared with the CNI group. Biopsy-proven acute rejection grade >/=2R occurred in 10.2% and 5.9% of everolimus- and CNI-treated patients, respectively, during months 12-36. Serious adverse events occurred in 37.3% and 19.6% of everolimus- and CNI-treated patients, respectively (p = 0.078). These results suggest that early CNI withdrawal after heart transplantation supported by everolimus, mycophenolic acid and steroids with lymphocyte-depleting induction is safe at intermediate follow-up. This regimen, used selectively, may offer adequate immunosuppressive potency with a sustained renal advantage.