Subclinical toxicity of calcineurin inhibitors in repeated protocol biopsies: an independent risk factor for chronic kidney allograft damage

Nephrotoxicity of calcineurin inhibitors as a risk factor for BK polyomavirus replication after kidney transplantation

BK polyomavirus-associated nephropathy (PyVAN) is responsible for a significant percentage of transplanted kidneys prematurely terminating their function. Its occurrence is closely related to the intensity of immunosuppressive therapy. In a group of 161 newly transplanted patients, we prospectively evaluated 457 protocol renal biopsies performed within the first year after transplantation. Using the calcineurin inhibitors (CI) nephrotoxicity score, the incidence of nephrotoxicity was monitored as a manifestation of excessive immunosuppression. Findings were correlated with clinical evidence of active BK polyomavirus (BKPyV) replication and PyVAN. Compared to the normal histology, nephrotoxicity was associated with more frequent BKPyV viremia and viruria (p = .01 and p < .01, respectively) and more common occurrence of PyVAN. The persistence of toxicity in the subsequent biopsy proved to be a negative risk factor of viremia and viruria (p = .03 and p < .01, respectively), independently of the initial BKPyV status. Toxicity could also be used as a predictor of viremia and viruria (p = .04 and p < .01, respectively) even in the absence of viral replication at the time of initial biopsy. The early histological manifestation of CI nephrotoxicity was associated with significant BKPyV reactivation in the risky first posttransplant year.

Calcineurin Inhibitors Nephrotoxicity Prevention Strategies With Stress on Belatacept-Based Rescue Immunotherapy: A Review of the Current Evidence

BACKGROUND

A traditional narrative review was performed to evaluate clinical studies that have examined the clinical implications, risk factors, and prevention of calcineurin inhibitors (CNIs) nephrotoxicity with stress on a belatacept-based rescue regimen.

METHODS

The Cochrane Library, PubMed/MEDLINE, EBSCO (Academic Search Ultimate), ProQuest (Central), and Excerpta Medical databases and Google scholar were searched using the keywords (CNI AND Nephrotoxicity prevention) OR ("Calcineurin inhibitor" AND Nephrotoxicity) OR (Tacrolimus AND Nephrotoxicity) OR (Ciclosporin AND Nephrotoxicity) OR (cyclosporine AND Nephrotoxicity) OR (Belatacept) OR (CNI Conversion) for the period from 1990 to 2020. Fifty-five related articles and reviews were found.

CONCLUSION

A better understanding of the mechanisms underlying calcineurin inhibitor nephrotoxicity could help in the individualization of therapy for and prevention of CNI nephrotoxicity. Identification of high-risk patients for CNI nephrotoxicity before renal transplantation enables better use and selection of immunosuppression with reduced adverse effects and, eventually, successful treatment of the kidney recipients. Belatacept conversion is a good and safe option in patients with deteriorating renal function attributed to CNI nephrotoxicity.

Dolutegravir-Based Antiretroviral Regimens for HIV Liver Transplant Patients in Real-Life Settings

Background and Objectives

Liver transplantation is now considered a safe procedure in patients with HIV because of the advent of potent antiretroviral therapies (ART).

Objective

We aimed to describe the use of dolutegravir-based maintenance ART in patients with HIV and liver transplant regularly followed in our hospital.

Methods

We searched the database of our Department of Infectious Diseases for liver transplant recipients receiving calcineurin inhibitor-based maintenance immunosuppression concomitantly treated with dolutegravir for at least 1 month.

Results

Ten HIV-positive liver transplant recipients were identified. At 4.6 ± 3.5 years post-transplant, all the patients were switched to dolutegravir-based therapies for treatment simplification. However, at 1 year after the switch, five of the ten patients returned to their previous ART regimens because of increased serum transaminases (n = 1), reversible increased serum creatinine (n = 4), repeated episodes of nausea/vomiting (n = 1) and variable out-of-range concentrations of tacrolimus or cyclosporine (n = 2). However, it should be recognized that these events cannot be unequivocally ascribed to dolutegravir and, in the case of increased serum creatinine, are predictable.

Conclusions

The management of HIV-positive liver transplant recipients in clinical practice is a complex task, where possibility of simplifying antiretroviral regimens must be balanced with the need to guarantee optimal immunosuppression and the finest treatment tolerability. A multidisciplinary approach involving physicians and clinical pharmacologists/pharmacists could help achieve this goal.

Targeting Calcium Release-activated Calcium Channel Is Not Sufficient to Prevent Rejection in Nonhuman Primate Kidney Transplantation

BACKGROUND

Calcineurin inhibitors successfully control rejection of transplanted organs but also cause nephrotoxicity. This study, using a rhesus monkey renal transplantation model, sought to determine the applicability of a new immunomodulatory drug inhibiting the store-operated calcium release-activated calcium channel of lymphocytes to control transplant rejection without nephrotoxicity.

METHODS

Animals underwent kidney transplantation and were treated with tacrolimus alone (n = 3), a CRACM1 inhibitor (PRCL-02) (n = 6) alone, or with initial tacrolimus monotherapy followed by gradual conversion at 3 weeks to PRCL-02 alone (n = 3). PRCL-02 was administered via a surgically inserted gastrostomy tube BID.

RESULTS

Dose-related drug exposure in monkeys was established and renal transplants were then performed using PRCL-02 monotherapy. Oral dosing of PRCL-02 was well tolerated and resulted in suppressed T-cell proliferation in in vitro MLR comparable to animals in the tacrolimus control arm. Animals receiving tacrolimus monotherapy were e on day 100 without rejection. PRCL-02 monotherapy only marginally prolonged graft survival (MST = 13.16 d; group 2) compared with untreated controls. Animals treated initially with tacrolimus and converted to PRCL-02 monotherapy had a mean graft survival of 35.3 days which was prolonged compared with PRCL-02 monotherapy but not compared with the tacrolimus-treated group. Pharmacokinetic studies showed inconsistent drug exposures despite attempts to adjust dose and exposure which may have contributed to the rejections.

CONCLUSIONS

We conclude that, in this nonhuman primate model of kidney transplantation, PRCL-02 demonstrated evidence of in vivo immunosuppressive activity but was inferior to tacrolimus treatment with respect to suppressing immune transplant rejection.

Dynamic 2-deoxy-2[18F] fluoro-D-glucose PET/MRI in human renal allotransplant patients undergoing acute kidney injury

Patients after solid organ kidney transplantation (KTX) often suffer from acute kidney injury (AKI). Parameters as serum creatinine indicate a loss of kidney function, although no distinction of the cause and prognosis can be made. Imaging tools measuring kidney function have not been widely in clinical use. In this observational study we evaluated 2-deoxy-2[18F] fluoro-D-glucose (FDG) PET/MRI in thirteen patients after KTX with AKI as a functional assessment of the graft. Twenty-four healthy volunteers served as control. General kidney performance (GKP), initial flow (IF) and renal response function (RF) were calculated by standardized uptake values (SUV) and time activity curves (TAC). The GKP measured for the total kidney and medulla was significantly higher in healthy patients compared to patients after KTX (p = 0.0002 and p = 0.0004, respectively), but no difference was found for the GKP of the cortex (p = 0.59). The IF in KTX patients correlated with renal recovery, defined as change in serum creatinine 10 days after PET/MRI (r = 0.80, p = 0.001). With regard to the RF, a negative correlation for tubular damage was found (r = -0.74, p = 0.004). In conclusion, parameters obtained from FDG PET/MRI showed a possible predictive feature for renal recovery in KTX patients undergoing AKI.

Low-dose Rituximab and Thymoglobulin Induction With Steroid-free Maintenance Immunosuppression and Protocol Biopsies Improves Long-term Patient and Graft Survival After Kidney Transplantation: Survival and Safety Outcomes in More Than 1100 Patients From a Single Center

BACKGROUND

Steroid-free maintenance immunosuppression after kidney transplantation provides acceptable patient and graft survival and minimizes steroid-associated side effects among recipients with a low immunological risk. However, the long-term outcomes of such protocols, incorporating low-dose rituximab and thymoglobulin induction along with protocol biopsies, in non-European populations remains underreported.

METHODS

We retrospectively analyzed 1142 consecutive kidney transplantations conducted at our center from July 2005 to October 2017. Immunosuppression protocol included induction with thymoglobulin and low-dose preoperative rituximab. Maintenance immunosuppression consisted of tacrolimus and mycophenolate mofetil; prednisolone was discontinued on postoperative day 5. Protocol biopsies were carried out at 3 months and at 1, 5, and 10 years after transplantation-in addition to the indicated biopsies. The 12-year patient and graft survival and posttransplantation complications were studied.

RESULTS

The analysis of outcomes was conducted for 1111 transplant recipients. Patients (70.59%) remained steroid-free at 12 years after transplantation. The patient survival rates at 1, 5, and 12 years were 97.7%, 94.8%, and 92.4%, respectively. The corresponding graft survival rates were 97.2%, 90.9%, and 86.1%, respectively. Biopsy-proven acute rejection occurred in 12.7% of recipients, including 3.5% subclinical rejections. The cumulative incidence of graft loss was 6.56% at 12.3 years. The overall incidence of death was 5.3%.

CONCLUSIONS

Steroid-free maintenance immunosuppression was associated with excellent long-term patient and graft survival rates and reduced incidence of prednisolone-related side effects, despite acceptable rejection rates. Low-dose rituximab with thymoglobulin induction with immediate steroid withdrawal and surveillance biopsies resulted in excellent long-term outcomes in our single-center experience.

Biomarkers for individualized dosage adjustments in immunosuppressive therapy using calcineurin inhibitors after organ transplantation

Calcineurin inhibitors (CNIs), such as cyclosporine A and tacrolimus, are widely used immunosuppressive agents for the prevention of post-transplantation rejection and have improved 1-year graft survival rates by up to 90%. However, CNIs can induce severe reactions, such as acute or chronic allograft nephropathy, hypertension, and neurotoxicity. Because CNIs have varied bioavailabilities, narrow therapeutic ranges, and individual propensities for toxic effects, therapeutic drug monitoring is necessary for all CNIs. Identifying the genetic polymorphisms in drug-metabolizing enzymes will help to determine personalized dosage regimens for CNIs, as CNIs are substrates for CYP3A5 and P-glycoprotein (P-gp, MDR1). CNIs are often concomitantly administered with voriconazole or proton pump inhibitors (PPIs), giving rise to drug interaction problems. Voriconazole and PPIs can increase the blood concentrations of CNIs, and both are primarily metabolized by CYP2C19. Thus, it is expected that interactions between CNIs and voriconazole or PPI would be affected by CYP2C19 and CYP3A5 polymorphisms. CNI-induced acute kidney injury (AKI) is a serious complication of transplantations. Neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule 1 (KIM-1) are noninvasive urinary biomarkers that are believed to be highly sensitive to CNI-induced AKI. In this article, we review the adverse events and pharmacokinetics of CNIs and the biomarkers related to CNIs, including CYP3A5, CYP2C19, MDR1, NGAL, and KIM-1. We hope that these data will help to identify the optimal biomarkers for monitoring CNI-based immunosuppressive therapy after organ transplantation.

Protocol biopsy of a transplanted kidney as a tool for monitoring adequacy of immunosuppressive therapy: 10 years of experience from a single transplant center

BACKGROUND

The aims of this prospective study were to determine the prevalence of clinically silent rejection changes and of nephrotoxicity of calcineurin inhibitors among repeated protocol biopsies of transplanted kidneys and to assess their impacts on chronic graft function and damage at the end of 1 year.

METHODS

We performed 424 protocol biopsies among 158 patients over the first year after transplantation. We monitored parameters of graft function and progression of chronic changes among subjects with clinically silent rejection or toxicity for comparison with a control cohort showing normal histological findings. The results of statistical tests were considered to be significant at a level of P < .05.

RESULTS

At 3 weeks, 3 months, and 12 months, there were normal histological findings among 30 (19%), 21 (14.8%), and 14 (11.3%) patients, respectively; subclinical rejection changes occurred in 49 (31%), 36 (25.4%), and 20 (16.2%) grafts, respectively. At the third week, histological signs of toxicity occurred in 33 (20.9%) patients with significant persistence despite reductions in calcineurin inhibitor doses. At the end of 1 year of follow-up, both subclinical and toxic changes produced similar increases in chronic changes as quantified by the Banff score and were significantly different from the control group (P < .05). Serum creatinine concentrations and glomerular filtration rates did not accurately reflect the degree of graft damage in the early posttransplantation period.

CONCLUSIONS

Subclinical rejection and toxic changes among a significant proportion of grafts are associated with progression of chronic changes already over the first year following transplantation. Hence they represent independent risk factors for the development of irreversible graft damage. Protocol biopsy seems to be an important method to monitor immunosuppressive therapy.