Efficacy and safety of tacrolimus compared with ciclosporin-A in renal transplantation: 7-year observational results

Association of Serum Osteoprotegerin With Vascular Calcification, and Cardiovascular and Graft Outcomes in Kidney Transplant Patients: Results From the KNOW-KT

BACKGROUND

Vascular calcification and stiffness contribute to increased cardiovascular morbidity in patients with chronic kidney disease. This study investigated associations between serum osteoprotegerin (OPG) levels and vascular calcification or stiffness to assess cardiovascular and graft outcomes in kidney transplant patients.

METHODS

The KoreaN cohort study for Outcome in patients With Kidney Transplantation was a prospective multicenter cohort study. Serum OPG levels were measured at baseline and 3 y after transplantation in 1018 patients. Patients were classified into high and low OPG groups according to median serum OPG levels. The median follow-up duration was 93.5 mo.

RESULTS

The mean age was 45.8 ± 11.7 y and 62.9% were men. Patients with high OPG had significantly higher coronary artery calcium scores, abdominal aortic calcification scores, and brachial-ankle pulse wave velocities than those with lower OPG; these parameters remained significant for 5 y after transplantation. The 3-y OPG levels were lower than baseline values ( P  < 0.001) and were positively correlated ( r  = 0.42, P  < 0.001). Multivariate Cox regression analysis showed that high OPG levels were significantly associated with posttransplant cardiovascular events ( P  = 0.008) and death-censored graft loss ( P  = 0.004). Similar findings regarding posttransplant cardiovascular events ( P  = 0.012) and death-censored graft loss ( P  = 0.037) were noted in patients with high OPG at the 3-y follow-up. Mediation analyses revealed that coronary artery calcium scores, abdominal aortic calcification scores, and brachial-ankle pulse wave velocities could act as mediators between serum OPG levels and posttransplant cardiovascular events.

CONCLUSIONS

Serum OPG concentration is associated with vascular calcification and stiffness and could be a significant risk factor for cardiovascular outcomes and graft loss in patients undergoing kidney transplantation.

Remission Induction of IgG4-related Membranous Nephropathy with Multitarget Therapy

IgG4-related membranous nephropathy (MN) is often refractory to glucocorticoid (GC) therapy, and treatment remains unclear. We herein report a 67-year-old Japanese man with IgG4-related MN and tubulointerstitial nephritis. A post-gastroscopy antibody test revealed Helicobacter pylori infection. After eradication, his proteinuria decreased indefinitely. We started prednisolone (30 mg/day), long-term GCs, and immunosuppressant therapy. However, remission proved challenging to achieve, with persistent proteinuria present at 1.0-2.0 g/gCr. We performed multitarget therapy for refractory IgG4-related MN, achieving proteinuria remission (<0.3 g/gCr). Multitarget therapy with low-dose GCs can resolve refractory IgG4-related MN through remission induction of proteinuria and minimize the risks associated with GC therapy.

The Effect of Voriconazole on Tacrolimus in Kidney Transplantation Recipients: A Real-World Study

Tacrolimus is an immunosuppressant with a narrow therapeutic window. Tacrolimus exposure increased significantly during voriconazole co-therapy. The magnitude of this interaction is highly variable, but it is hard to predict quantitatively. We conducted a study on 91 kidney transplantation recipients with voriconazole co-therapy. Furthermore, 1701 tacrolimus concentration data were collected. Standard concentration adjusted by tacrolimus daily dose (C/D) and weight-adjusted standard concentration (CDW) increased to 6 times higher during voriconazole co-therapy. C/D and CDW increased with voriconazole concentration. Patients with the genotype of CYP3A5 *3/*3 and CYP2C19 *2/*2 or *2/*3 were more variable at the same voriconazole concentration level. The final prediction model could explain 54.27% of the variation in C/D and 51.11% of the variation in CDW. In conclusion, voriconazole was the main factor causing C/D and CDW variation, and the effect intensity should be quantitative by its concentration. Kidney transplant recipients with CYP3A5 genotype of *3/*3 and CYP2C19 genotype of *2/*2 and *2/*3 should be given more attention during voriconazole co-therapy. The prediction model established in this study may help to reduce the occurrence of rejection.

Influence of Calcineurin Inhibitor Choice on Outcomes in Kidney Transplant Recipients Aged ≥60 Y: A Collaborative Transplant Study Report

BACKGROUND

Patients aged ≥60 y represent the fastest growing population among kidney transplant recipients and waitlist patients. They show an elevated infection risk and are frequently transplanted with multiple human leukocyte antigen mismatches. Whether the choice of calcineurin inhibitor influences graft survival, mortality, or key secondary outcomes such as infections in this vulnerable recipient population is unknown.

METHODS

A total of 31 177 kidney transplants from deceased donors performed between 2000 and 2019 at European centers and reported to the Collaborative Transplant Study were analyzed using multivariable Cox and logistic regression analyses. All recipients were ≥60 y old and received tacrolimus (Tac) or cyclosporine A on an intention-to-treat basis, combined with mycophenolic acid or azathioprine plus/minus steroids.

RESULTS

The risk of 3-y death-censored graft loss and patient mortality did not differ significantly between Tac- and cyclosporine A-treated patients (hazard ratio 0.98 and 0.95, P = 0.74 and 0.20, respectively). No difference was found in the overall risk of hospitalization for infection (hazard ratio = 0.95, P = 0.19); however, a lower incidence of rejection treatment (hazard ratio = 0.81, P < 0.001) was observed in Tac-treated patients. Assessment of pathogen-specific hospitalizations revealed no difference in the risk of hospitalization due to bacterial infection (odds ratio = 1.00, P = 0.96), but a significantly higher risk of hospitalization due to human polyomavirus infection was found among Tac-treated patients (odds ratio = 2.45, P = 0.002). The incidence of de novo diabetes was higher for Tac-based immunosuppression (odds ratio = 1.79, P < 0.001).

CONCLUSIONS

Calcineurin inhibitor selection has no significant influence on death-censored graft survival, mortality, and overall infection risk in ≥60-y-old kidney transplant recipients.

Belatacept in renal transplantation in comparison to tacrolimus and molecular understanding of resistance pattern: Meta-analysis and systematic review

BACKGROUND

The T-cell costimulation blocking agent belatacept has been identified as a possible substitute for calcineurin inhibitors, however, no consensus has been established against its use over the standard care agent Tacrolimus.

AIM

To evaluate the effectiveness of belatacept based maintenance immuno-suppressive regimens in comparison to tacrolimus in renal transplantion.

METHODS

We did extensive search of all the available literature comparing the role of belatacept to tacrolimus in renal transplant recipients by searching the PubMed, Embase, Cochrane, Crossref, Scopus, clinical trials registry on October 5, 2020.

RESULTS

The literature search identified four randomized controlled trials (n = 173 participants) comparing belatacept with tacrolimus. There was no significant difference in estimated renal function at 12 mo [mean difference 4.12 mL/min/1.73 m², confidence interval (CI): -2.18 to 10.42, P = 0.20]. Further, belatacept group was associated with significant increase in biopsy proven acute rejection [relative risk (RR) = 3.27, CI: 0.88 to 12.11, P = 0.08] and worse 12 mo allograft survival (RR = 4.51, CI: 1.23 to 16.58, P = 0.02). However, incidence of new onset diabetes mellitus was lower with belatacept at 12 mo (RR = 0.26, CI: 0.07 to 0.99, P = 0.05).

CONCLUSION

The evidence reviewed in this meta-analysis suggested that belatacept-based maintenance immunosuppression regimens were associated with an increased risk allograft loss in renal transplant recipients with equivalent renal functioning against standard tacrolimus; however, observed significantly reduced new onset diabetes mellitus after transplantation incidence and lower serum low density lipid profile levels in belatacept group. In addition, the adaptation of belatacept in renal transplantation has been forestalled by increased rates of rejection and resistance owing to development of various effector memory T cells through, parallel differentiation and immunological plasticity.

Humoral Alloreactivity in VCA Recipients: Should We Learn From Our Experience?

Initially overlooked in favor of T cell-mediated rejection, the importance of the humoral alloimmune response has progressively emerged. As a result, antibody-mediated rejection is now widely recognized as the main cause of late allograft loss in most (if not all) types of solid-organ transplantation. Over the last 2 decades, vascularized composite allotransplantation (VCA) has appeared for replacing tissue defects in patients for whom no other satisfactory reconstructive options were available. Although it is now clear that VCA recipients can develop donor-specific antibodies, conclusions made in solid organ transplantation regarding antibody-mediated rejection may not systematically apply to VCA. Here, we propose to use the experience gained in organ transplantation to shed light on the path that shall be followed to evaluate and manage humoral alloreactivity in VCA recipients.

Effect of Everolimus with Low-Dose Tacrolimus on Development of New-Onset Diabetes After Transplantation and Allograft Function in Kidney Transplantation: A Multicenter, Open-Label, Randomized Trial

Background

This randomized controlled trial aimed to investigate the effect of everolimus (EVL) with low-dose tacrolimus (Tac) on the development of post-transplantation diabetes mellitus (PTDM) in kidney transplantation (KT).

Material/Methods

Seventy-seven kidney transplant patients from 4 transplant centers were included. Patients were randomized to the “EVL group” (n=38) and the “TAC group” (n=39). The target Tac trough level was 2 to 5 ng/mL in the EVL group and 5 to 10 ng/mL in the TAC group.

Results

The 1-year cumulative incidence of PTDM in all patients was 7.8%, and no difference was found between the 2 groups (P=0.0819). Insulin resistance measured with the homeostatic model assessment for insulin resistance showed a significant increase only in the TAC group (1.11 to 1.30, P=0.0492). Allograft rejection rate and estimated glomerular filtration rate (eGFR) follow-ups every 3 months were not significantly different between the 2 groups. However, the EVL group showed a significant increase in the mean eGFR at 9 months and 12 months after KT compared to the baseline value (P=0.0242 and 0.0491, respectively).

The EVL group showed lower insulin resistance and higher allograft function in comparison to the TAC group.

Conclusions

EVL-based immunosuppressive therapy with lower Tac exposure could be a safer alternative for maintenance treatment.

Quantifying spillover benefits in value assessment: a case study of increased graft survival on the US kidney transplant waitlist

AIM

To quantify the wider impacts of increased graft survival on the size of the kidney transplant waitlist and health and economic outcomes.

MATERIALS AND METHODS

The analysis employed known steady-state solutions to a double-queueing system as well as simulations of this system. Baseline input parameters were sourced from the Organ Procurement and Transplant Network and the United States Renal Data System. Three increased graft survival scenarios were modeled: decreases in repeat transplant candidates joining the waitlist of 25%, 50%, and 100%.

RESULTS

Under the three scenarios, we estimated that the US waitlist size would decrease from 91,822 to 85,461 (6.9% decrease), 80,073 (12.8% decrease), and 69,340 (24.4% decrease), respectively. Patient outcomes improved, with lifetime quality-adjusted life years (QALYs) for a 1-year cohort of transplant recipients increasing by 10,010, 16,888, and 43,345 over the three scenarios. Discounted lifetime costs for the cohort in the new steady state were lower by $1.6 billion, $2.3 billion, and $9.0 billion for each scenario, respectively. Spillover impacts (i.e. benefits that accrued beyond the patients who directly experienced increased graft survival) accounted for 41-48% of the QALY gains and ranged from cost increases of 3.3% to decreases of 5.5%.

LIMITATIONS

The model is a simplification of reality and does not account for the full degree of patient heterogeneity occurring in the real world. Health economic outcomes are extrapolated based on the assumption that the median patient is representative of the overall population.

CONCLUSIONS

Increasing graft survival reduces demand from repeat transplants candidates, allowing additional candidates to receive transplants. These spillover impacts decrease waitlist size and shorten wait times, leading to improvements in graft and patient survival as well as quality-of-life. Cost-effectiveness analyses of treatments that increase kidney graft survival should incorporate spillover benefits that accrue beyond the direct recipient of an intervention.

Effects of tacrolimus on autophagy protein LC3 in puromycin-damaged mouse podocytes

Objective

To investigate the mechanism through which tacrolimus, often used to treat refractory nephropathy, protects against puromycin-induced podocyte injury.

Methods

An in vitro model of puromycin-induced podocyte injury was established by dividing podocytes into three groups: controls, puromycin only (PAN group), and puromycin plus tacrolimus (FK506 group). Podocyte morphology, number, apoptosis rate and microtubule associated protein 1 light chain 3 alpha (LC3) expression were compared.

Results

Puromycin caused podocyte cell body shrinkage and loose intercellular connections, but podocyte morphology in the FK506 group was similar to controls. The apoptosis rate was lower in the FK506 group versus PAN group. The low level of LC3 mRNA observed in untreated podocytes was decreased by puromycin treatment; however, levels of LC3 mRNA were higher in the FK506 group versus PAN group. Although LC3-I and LC3-II protein levels were decreased by puromycin, levels in the FK506 group were higher than the PAN group. Fewer podocyte autophagosomes were observed in the control and FK506 groups versus the PAN group. Cytoplasmic LC3-related fluorescence intensity was stronger in control and FK506 podocytes versus the PAN group.

Conclusions

Tacrolimus inhibited puromycin-induced mouse podocyte damage by regulating LC3 expression and enhancing autophagy.

Improved ability to achieve target trough levels with liquid versus capsule tacrolimus in kidney transplant patients with HIV on protease inhibitor- or cobicistat-based regimens

HIV + patients are commonly accepted for kidney transplantation. However, patients on protease inhibitor (PI)- or cobicistat (cobi)-based regimens have trouble achieving optimal tacrolimus (Tac) levels. Our study compared the ability to achieve target levels using liquid versus immediate-release capsule Tac in kidney transplant patients with HIV on PI- or cobi-based regimens. The study included four kidney transplant patients who were converted to liquid Tac due to inability to achieve acceptable drug levels on the capsule formulation. Tac trough levels were analyzed retrospectively to compare target levels before and after conversion. The individual patient time in the therapeutic range (TTR) was calculated using Rosendaal's linear interpolation method, and the difference between before and after conversion TTR was determined. In combined data, 44.63% of all Tac trough levels were within the target range after conversion to liquid Tac compared to 22.07% prior to conversion (P < .001). Furthermore, 3.31% and 7.44% of Tac trough levels were lower than 3 ng/mL or higher than 12 ng/mL, respectively, after conversion compared to 11.72% (P = .0564) and 24.14% (P < .0001) prior to conversion. The overall mean TTR was 45.1% after conversion to liquid Tac compared to 16.2% prior to conversion (P = .097). Finally, the coefficient of variation for Tac trough levels was 42.6 after conversion compared to 56.4 prior to conversion. A significantly improved ability to achieve target trough Tac levels was achieved with liquid Tac extemporaneous versus capsule formulation in kidney transplant patients with HIV taking a PI- or cobi-based regimen.

Kidneys From Elderly Deceased Donors-Is 70 the New 60?

There is a growing shortage of kidney donors leading to extended transplant waiting times associated with increased mortality. To expand the donor pool, clinicians nowadays regularly accept organs from elderly donors, including those aged ≥70 years. There is only limited and conflicting data whether kidneys from these elderly donors allow for satisfactory allograft outcome rates. To asses this question, the 5-year death censored graft survival of 116,870 adult first deceased donor kidney allograft recipients that were transplanted at European centers between 1997 and 2016 and reported to the “Collaborative Transplant Study” were analyzed using Kaplan–Meier analysis and country stratified Cox regression. The combinations of the two transplant periods 1997–2006 and 2007–2016 with the donor age categories 18–49, 50–59, 60–69, and ≥70 years were considered. From 1997–2006 to 2007–2016, the median donor age increased from 50 to 55 years and the proportion of kidneys from ≥60-year-old donors rose from 24.1 to 38.8%. At the same time, the proportion of kidneys from ≥70-year-old donors more than doubled (6.7 vs. 15.4%). Between 1997–2006 and 2007–2016, the 5-year graft survival improved in all donor age categories. During 2007–2016, the 5-year death censored graft survival of kidneys from ≥70-year-old donors was comparable to that of kidneys from 60 to 69-year-old donors during 1997–2006. This was true both for younger recipients (18–64 years) and older recipients (≥65 years). Among the younger recipients, 45–64-year-old recipients showed the best death censored graft survival rates for kidneys from old donors. In the country-stratified Cox regression analysis, compared to the reference of grafts from 18 to 49-year-old donors, the hazard ratio for grafts from ≥70-year-old donors during 2007–2016 was 1.92, exactly the same as the hazard ratio for grafts from 60 to 69-year-old donors during 1997–2006. Our analysis indicates that within only one further decade (1997–2006 vs. 2007–2016) the 5-year death censored graft survival of kidneys from ≥70-year old donors improved to the level of kidneys from 60 to 69-year-old donors in the previous decade.

Effect of initial immunosuppression on long-term kidney transplant outcome in immunological low-risk patients

BACKGROUND

Few studies have evaluated the effect of different immunosuppressive strategies on long-term kidney transplant outcomes. Moreover, as they were usually based on historical data, it was not possible to account for the presence of pretransplant donor-specific human-leukocyte antigen antibodies (DSA), a currently recognized risk marker for impaired graft survival. The aim of this study was to evaluate to what extent frequently used initial immunosuppressive therapies increase graft survival in immunological low-risk patients.

METHODS

We performed an analysis on the PROCARE cohort, a Dutch multicentre study including all transplantations performed in the Netherlands between 1995 and 2005 with available pretransplant serum (n = 4724). All sera were assessed for the presence of DSA by a luminex single-antigen bead assay. Patients with a previous kidney transplantation, pretransplant DSA or receiving induction therapy were excluded from the analysis.

RESULTS

Three regimes were used in over 200 patients: cyclosporine (CsA)/prednisolone (Pred) (n = 542), CsA/mycophenolate mofetil (MMF)/Pred (n = 857) and tacrolimus (TAC)/MMF/Pred (n = 811). Covariate-adjusted analysis revealed no significant differences in 10-year death-censored graft survival between patients on TAC/MMF/Pred therapy (79%) compared with patients on CsA/MMF/Pred (82%, P = 0.88) or CsA/Pred (79%, P = 0.21). However, 1-year rejection-free survival censored for death and failure unrelated to rejection was significantly higher for TAC/MMF/Pred (81%) when compared with CsA/MMF/Pred (67%, P < 0.0001) and CsA/Pred (64%, P < 0.0001).

CONCLUSION

These results suggest that in immunological low-risk patients excellent long-term kidney graft survival can be achieved irrespective of the type of initial immunosuppressive therapy (CsA or TAC; with or without MMF), despite differences in 1-year rejection-free survival.

Follicular Helper T Cell Derived Exosomes Promote B Cell Proliferation and Differentiation in Antibody-Mediated Rejection after Renal Transplantation

Follicular helper T cells (Tfh cells) are closely related to the occurrence and development of antibody-mediated rejection (AMR) after renal transplantation. Exosomes play a key role in the rejection after organ transplantation. However, whether Tfh-derived exosomes are involved in AMR has not been reported. We collected peripheral blood from 42 kidney transplant patients and found no significant differences in CD4+CXCR5+ and CD4+CXCR5+CXCR3+CCR6-exosomes between AMR and non-AMR groups, whereas the proportion of CD4+CXCR5+CXCR3-exosomes was significantly higher in AMR group than that in non-AMR group; CTLA-4 expression of CD4+CXCR5+exosomes was significantly lower in AMR group than that in non-AMR group. HLA-G expression was not significantly different between two groups. We further separated CD4+CXCR5+cells from patients by magnetic beads. Coculture experiments showed that Tfh cell-derived exosomes in AMR patients significantly promoted B cell proliferation and differentiation, compared with non-AMR group, the percentage of B cells and plasma cells increased by 87.52% and 110.2%, respectively. In conclusion, our study found that Tfh cell-derived exosomes could promote the proliferation and differentiation of B cells and they may play an important role in the development of AMR after renal transplantation.