Tremor induced by Calcineurin inhibitor immunosuppression: a single-centre observational study in kidney transplanted patients

Tremor after solid organ transplantation: Results from the TransplantLines Biobank and Cohort Study

BACKGROUND AND PURPOSE

Tremor is a frequent complaint of solid organ transplant recipients. We report on the largest population investigated with clinical neurophysiological methods. Our aim is to objectively establish the tremor prevalence and syndrome in the largest population of solid organ transplant recipients.

METHODS

Tremor was measured in heart, kidney, liver, and lung recipients, using accelerometers during rest, postural, and weight-loaded conditions. The 95th percentile of healthy kidney donors' tremor amplitude was used as the cutoff to determine the presence of tremor in transplant recipients. Tremor frequency, frequency variability, and effect of loading were used to investigate enhanced physiological tremor as the likely tremor syndrome. Impact on activities of daily life was assessed, and correlations with tacrolimus blood levels were investigated.

RESULTS

Tremor was present in 52% of 246 transplant recipients, typically in postural positions. Mean tremor frequency was 6.1 (±2.0) Hz; mean tremor variability was 2.6 (±1.8) Hz. A frequency decrease upon loading was found in 83% of patients with tremor. Sixty-five percent of patients met formal clinical neurophysiological criteria for enhanced physiological tremor. Tremor-related impairment was present in 55% and correlated with tremor amplitude (ρ = 0.23, p ≤ 0.001). In a binominal regression analysis, tacrolimus blood levels were independently associated with tremor prevalence (p = 0.009).

CONCLUSIONS

More than half of solid organ transplant recipients experience a tremor that best fits the syndrome of enhanced physiological tremor. This is the first objective study on tremor that has established a better understanding of the neurophysiological mechanisms of tremor in a large population of solid organ transplant recipients.

Holistic care and symptom management for pediatric kidney transplant recipients

While many aspects of life may improve substantially for children and young people undergoing kidney transplant, there may be new challenges including symptoms that can be detrimental to health-related quality of life. Addressing symptoms requires attention to patient and family perspectives and a holistic approach grounded in symptom management. The interdisciplinary pediatric nephrology transplant team should be attuned to the prevalence of common symptoms including fatigue, anxiety, depression, post-traumatic stress, pain, and sleep disturbances, as well as poor body image and sexual health. These common symptoms require regular assessment with a focus on appropriate interventions and how care may be impacted by transplant status.

A report of a prospective randomized trial of extended-release tacrolimus versus immediate release tacrolimus after liver transplantation with anti-thymocyte induction in a steroid free protocol

PURPOSE

Our study hypothesis was that once daily dosing of extended-release tacrolimus (XRT) would be a safe and effective immunosuppression (IS) with the potential to decrease adverse events (AEs) associated with immediate release tacrolimus (IRT) after liver transplantation (LT).

METHODS

All patients receiving LT at our center received rabbit anti-thymocyte globulin (RATG) induction therapy. Eligible patients were randomized in a 1:1 fashion to receive either XRT or IRT. Antimicrobial prophylaxis was the same between arms, and both groups received an antimetabolite for the first 6 months following LT. Patients were then followed at pre-determined study intervals for the following year after LT. We administered the RAND-36SF survey to assess patient's health-related quality of life at pre-determined intervals. All analysis was performed with an intention to treat basis.

RESULTS

We screened 194 consecutive patients and enrolled 110. Our control and study arms were well matched. Transplant characteristics were similar between groups. At all timepoints, both arms had similar serum creatinine and estimated glomerular filtration rate (eGFR), calculated by MDRD6 equation, with post-transplant GFRs between 60 and 70 mL/min/1.73 m2 . Tacrolimus trough levels were similar between arms. The XRT arm had fewer AEs (166) and fewer serious AEs (70) compared to IRT (201 and 99, respectively). AEs most commonly were renal, infectious, or gastrointestinal in nature. While not statistically significant, XRT was held temporarily (25 vs. 35 cases) or discontinued (3 vs. 11 cases) less frequently than IRT and had fewer instances of rejection (7 vs. 12 cases).

CONCLUSION

This analysis showed that XRT is safe and effective as de novo maintenance IS in a steroid-free protocol with RATG.

The association between tacrolimus exposure and tremor, headache and insomnia in adult kidney transplant recipients: A systematic review

PURPOSE

Tremor, headache and insomnia have been linked to the immunosuppressant, tacrolimus. The aim of this systematic review was to determine if there is a correlation between tacrolimus exposure and new-onset tremor, headache and insomnia experienced by adult kidney transplant recipients.

METHODS

PubMed, Embase, Cochrane Library and CINAHL databases were searched up to 11 April 2023 for published studies which reported on tacrolimus exposure in adult kidney transplant recipients, alongside information on treatment-emergent neurologic manifestations, including tremor, headache and insomnia. Review articles, case studies, conference abstracts and articles not published in English in peer-reviewed journals were excluded. The Physiotherapy Evidence Database and Newcastle-Ottawa Quality Assessment Scales were used to assess risk of bias. Extracted data was analysed via a narrative synthesis.

RESULTS

Eighteen studies involving 4030 patients in total were included in the final analysis. These comprised five randomised control trials and thirteen observational studies. Studies failed to find significant association between tacrolimus trough concentrations in whole blood and the incidence of neurologic side effects such as tremor, headache and insomnia; however, in one study the incidence of toxicity requiring a dose reduction increased with increasing, supratherapeutic targeted levels. Females, especially Black females, and older age were positively associated with the prevalence of neurologic adverse effects. Results were conflicting regarding whether extended-release formulations were associated with fewer neurologic complications than immediate-release formulations.

CONCLUSION

The varied study designs and criteria for reporting tremor, headache and insomnia impacted on the quality of the data for exploring the relationship between tacrolimus exposure and the onset of neurologic manifestations experienced after kidney transplantation. Studies that examine defined neurologic complications as the primary outcome, and that consider novel markers of tacrolimus exposure while assessing the potential contribution of multiple covariate factors, are required.

Health-related Quality of Life and Fatigue in Liver Transplant Recipients Receiving Tacrolimus Versus Sirolimus-based Immunosuppression: Results From a Randomized Trial

BACKGROUND

The impact of different immunosuppression regimes on the health-related quality of life (HRQoL) and the severity of fatigue in liver transplant recipients is largely unknown. We investigated the impact of a sirolimus-based regimen compared with a tacrolimus (TAC)-based regimen on the HRQoL and the severity of fatigue.

METHODS

In this multicenter, open-label, randomized, controlled trial, 196 patients were randomized 90 d after transplantation to (1) once daily normal-dose TAC or (2) once daily combination therapy of low-dose sirolimus and TAC. HRQoL was measured with the EQ-5D-5L questionnaire, the EQ-visual analog scale, and the severity of fatigue questionnaire Fatigue Severity Score (FSS). The EQ-5D-5L scores were translated to societal values. We examined the HRQoL and the FSS over the course of the study by fitting generalized mixed-effect models.

RESULTS

Baseline questionnaires were available for 87.7% (172/196) of the patients. Overall, patients reported the least problems in the states of self-care and anxiety/depression and the most problems in the states of usual activities and pain/discomfort. No significant differences in HrQol and FSS were seen between the 2 groups. During follow-up, the societal values of the EQ-5D-5L health states and the patient's self-rated EQ-visual analog scale score were a little lower than those of the general Dutch population in both study arms.

CONCLUSIONS

The HRQoL and FSS were comparable in the 36 mo after liver transplantation in both study groups. The HRQoL of all transplanted patients approximated that of the general Dutch population, suggesting little to no residual symptoms in the long term after transplantation.

Tremor Induced by Cyclosporine, Tacrolimus, Sirolimus, or Everolimus: A Review of the Literature

Calcineurin inhibitors such as cyclosporine and tacrolimus are immunosuppressant drugs that are known to induce tremors. Non-calcineurin inhibitors such as sirolimus and everolimus have also reportedly been accompanied by tremors, albeit less likely. However, the prevalence rates reported in the literature are notably wide, and the risk profiles for these drug-induced tremors are less understood. We searched PubMed to extract data on the risk of tremors with these drugs when prescribed for various transplant and non-transplant indications. We ascertained whether the risk of drug-induced tremor is influenced by the underlying diagnosis, dosing formulations, drug concentrations, and blood monitoring. We extracted data on treatment strategies and outcomes for tremors. Articles were primarily screened based on English language publications, abstracts, and studies with n ≥ 5, which included case series, retrospective studies, case-controlled studies, and prospective studies. We found 81 eligible studies comprising 33 cyclosporine, 43 tacrolimus, 6 sirolimus, and 1 everolimus that discussed tremor as an adverse event. In the pooled analysis of studies with n > 100, the incidence of tremor was 17% with cyclosporine, 21.5% with tacrolimus, and 7.8% with sirolimus and everolimus together. Regarding the underlying diagnosis, tremor was more frequently reported in kidney transplant (cyclosporine 28%, tacrolimus 30.1%) and bone marrow transplant (cyclosporine 40%, tacrolimus 41.9%) patients compared with liver transplant (cyclosporine 9%, tacrolimus 11.5%) and nontransplant indications (cyclosporine 21.5%, tacrolimus 11.3%). Most studies did not report whether the risk of tremors correlated with drug concentrations in the blood. The prevalence of tremors when using the twice-daily formulation of tacrolimus was nearly the same as the once-daily formulation (17% vs 18%). Data on individual-level risk factors for tremors were lacking. Except for three studies that found some benefit to maintaining magnesium levels, there were minimal data on treatments and outcomes. A large body of data supports a substantive and wide prevalence of tremor resulting from tacrolimus use followed by cyclosporine, especially in patients receiving a kidney transplant. However, there is little reporting on the patient-related risk factors for tremor, risk relationship with drug concentrations, treatment strategies, and outcomes.

Magnetic Resonance Guided Focused Ultrasound Thalamotomy for Treatment of Severe Essential Tremor in a Lung Transplant Recipient-A Case Report

Calcineurin inhibitor-related tremors occur in up to 50% of solid organ transplant recipients and are disabling in severe cases. We describe a bilateral lung transplant recipient with essential tremors that significantly worsened after tacrolimus initiation. She did not have improvement with the change to extended-release tacrolimus, the use of everolimus as a calcineurin inhibitor-sparing agent, or the addition of primidone, clonazepam, or propranolol. She underwent magnetic resonance-guided focused ultrasound thalamotomy with significant improvement in her tremor and activities of daily living.

Tremor, Daily Functioning, and Health-Related Quality of Life in Solid Organ Transplant Recipients

Solid organ transplant recipients (SOTR) frequently report tremor. Data concerning tremor-related impairment and its potential impact on health-related quality of life (HRQoL) are lacking. This cross-sectional study assesses impact of tremor on activities of daily living and HRQoL using validated questionnaires among SOTR enrolled in the TransplantLines Biobank and Cohort Study. We included 689 SOTR (38.5% female, mean [±SD] age 58 [±14] years) at median [interquartile range] 3 [1-9] years after transplantation, of which 287 (41.7%) reported mild or severe tremor. In multinomial logistic regression analyses, whole blood tacrolimus trough concentration was an independent determinant of mild tremor (OR per µg/L increase: 1.11, 95% CI: 1.02 to 1.21, p = 0.019). Furthermore, in linear regression analyses, severe tremor was strongly and independently associated with lower physical and mental HRQoL (β = -16.10, 95% CI: -22.23 to -9.98, p < 0.001 and β = -12.68, 95% CI: -18.23 to -7.14, p < 0.001 resp.). SOTR frequently report tremor-related impairment of activities of daily living. Tacrolimus trough concentrations appeared as a main determinant of tremor among SOTR. The strong and independent association of tremor-related impairment with lower HRQoL warrants further studies into the effects of tacrolimus on tremor. Clinical Trial Registration: ClinicalTrials.gov, Identifier NCT03272841.

Phenomenology and Physiology of Tacrolimus Induced Tremor

Background

Tacrolimus is a potent immunosuppressant drug commonly used after solid organ transplant surgery. The use of this drug is frequently associated with the emergence of tremors. There is little information on the clinical and physiological characteristics of tacrolimus-induced tremors. Characterizing these tremors is essential as they can promote the development of specific therapies.

Methods

We describe four patients placed on tacrolimus immunosuppressant therapy following kidney transplant surgery and who developed tremors impacting their daily functional activities. We describe the clinical and physiological characteristics of the tremor and the response generated after a limb cooling test.

Results

A postural and kinetic tremor mainly involving the distal hands was observed in our cohort. In the accelerometer-based assessment, the tremor amplitude was noted to be mild to moderate, and the frequency was 5-6 Hz. Cooling the forearm and the hand led to a temporary albeit significant reduction of tremor amplitude (p = 0.03). Limb cooling lowered the tremor frequency by 1 Hz in two patients with no change in the other two patients, and the statistical comparison was not significant (p > 0.05).

Conclusions

Limb cooling may be pursued as a therapeutic option for addressing tacrolimus-induced tremor, as the patients in our cohort benefitted from temporary tremor suppression.

Helper T Cell (CD4+) Targeted Tacrolimus Delivery Mediates Precise Suppression of Allogeneic Humoral Immunity

Antibody-mediated rejection (ABMR) is a major cause of dysfunction and loss of transplanted kidney. The current treatments for ABMR involve nonspecific inhibition and clearance of T/B cells or plasma cells. However, the prognosis of patients following current treatment is poor. T follicular helper cells (Tfh) play an important role in allograft-specific antibodies secreting plasma cell (PC) development. Tfh cells are therefore considered to be important therapeutic targets for the treatment of antibody hypersecretion disorders, such as transplant rejection and autoimmune diseases. Tacrolimus (Tac), the primary immunosuppressant, prevents rejection by reducing T cell activation. However, its administration should be closely monitored to avoid serious side effects. In this study, we investigated whether Tac delivery to helper T (CD4+) cells using functionalized mesoporous nanoparticles can block Tfh cell differentiation after alloantigen exposure. Results showed that Tac delivery ameliorated humoral rejection injury in rodent kidney graft by suppressing Tfh cell development, PC, and donor-specific antibody (DSA) generation without causing severe side effects compared with delivery through the drug administration pathway. This study provides a promising therapeutic strategy for preventing humoral rejection in solid organ transplantation. The specific and controllable drug delivery avoids multiple disorder risks and side effects observed in currently used clinical approaches.

Machine Learning-Based Prediction Method for Tremors Induced by Tacrolimus in the Treatment of Nephrotic Syndrome

Tremors have been reported even with a low dose of tacrolimus in patients with nephrotic syndrome and are responsible for hampering the day-to-day work of young active patients with nephrotic syndrome. This study proposes a neural network model based on seven variables to predict the development of tremors following tacrolimus. The sensitivity and specificity of this algorithm are high. A total of 252 patients were included in this study, out of which 39 (15.5%) experienced tremors, 181 patients (including 32 patients who experienced tremors) were randomly assigned to a training dataset, and the remaining were assigned to an external validation set. We used a recursive feature elimination algorithm to train the training dataset, in turn, through 10-fold cross-validation. The classification performance of the classifer was then used as the evaluation criterion for these subsets to find the subset of optimal features. A neural network was used as a classification algorithm to accurately predict tremors using the subset of optimal features. This model was subsequently tested in the validation dataset. The subset of optimal features contained seven variables (creatinine, D-dimer, total protein, calcium ion, platelet distribution width, serum kalium, and fibrinogen), and the highest accuracy obtained was 0.8288. The neural network model based on these seven variables obtained an area under the curve (AUC) value of 0.9726, an accuracy of 0.9345, a sensitivity of 0.9712, and a specificity of 0.7586 in the training set. Meanwhile, the external validation achieved an accuracy of 0.8214, a sensitivity of 0.8378, and a specificity of 0.7000 in the validation dataset. This model was capable of predicting tremors caused by tacrolimus with an excellent degree of accuracy, which can be beneficial in the treatment of nephrotic syndrome patients.

Immunosuppressive drugs and associated complications in abdominal organ transplantation

PURPOSE OF REVIEW

Intensive care management of patients who have undergone organ transplantation of liver, small bowel, pancreas, and/or kidney requires a basic knowledge of immunosuppression principles and the management of immunosuppressive medications. This review highlights the core principles of immunosuppression management in abdominal organ transplantation with a focus on complications arising from immunosuppressive drugs, both in the immediate postoperative period and in long-term usage.

RECENT FINDINGS

The general principles of management of immunosuppression in the abdominal organ transplant population have remained largely unchanged. Improvements in drug monitoring coupled with improvements in knowledge of pathways involved in allograft rejection have further refined immunosuppressive therapy. Infectious and central nervous system complications remain prevalent and are common complications of immunosuppressive drug therapy.

SUMMARY

For the intensive care professional who cares for abdominal organ transplant recipients, a foundational knowledge of the core principles of immunosuppression management is essential. In addition, an understanding of the common immunosuppressive drug regimens and the complications associated with these regimens is required for optimal management, risk assessment, and outcomes.

Movement Disorders and Liver Disease

The association of movement disorders with structural or functional hepatic disease occurs in three principal scenarios: (1) combined involvement of both organ systems from a single disease entity, (2) nervous system dysfunction resulting from exposure to toxic compounds in the setting of defective hepatic clearance, or (3) hepatic and/or neurological injury secondary to exposure to exogenous drugs or toxins. An important early step in the workup of any patient with combined movement disorders and liver disease is the exclusion of Wilson's disease. Diagnostic delay remains common for this treatable disorder, and this has major implications for patient outcomes. Thereafter, a structured approach integrating variables such as age of onset, tempo of progression, nature and severity of liver involvement, movement disorder phenomenology, exposure to drugs/toxins and laboratory/neuroimaging findings is key to ensuring timely diagnosis and disease‐specific therapy. Herein, we provide an overview of disorders which may manifest with a combination of movement disorders and liver disease, structured under the three headings as detailed above. In each section, the most common disorders are discussed, along with important clinical pearls, suggested diagnostic workup, differential diagnoses and where appropriate, treatment considerations.

Influence of Germline Genetics on Tacrolimus Pharmacokinetics and Pharmacodynamics in Allogeneic Hematopoietic Stem Cell Transplant Patients

Tacrolimus exhibits high inter-patient pharmacokinetics (PK) variability, as well as a narrow therapeutic index, and therefore requires therapeutic drug monitoring. Germline mutations in cytochrome P450 isoforms 4 and 5 genes (CYP3A4/5) and the ATP-binding cassette B1 gene (ABCB1) may contribute to interindividual tacrolimus PK variability, which may impact clinical outcomes among allogeneic hematopoietic stem cell transplantation (HSCT) patients. In this study, 252 adult patients who received tacrolimus for acute graft versus host disease (aGVHD) prophylaxis after allogeneic HSCT were genotyped to evaluate if germline genetic variants associated with tacrolimus PK and pharmacodynamic (PD) variability. Significant associations were detected between germline variants in CYP3A4/5 and ABCB1 and PK endpoints (e.g., median steady-state tacrolimus concentrations and time to goal tacrolimus concentration). However, significant associations were not observed between CYP3A4/5 or ABCB1 germline variants and PD endpoints (e.g., aGVHD and treatment-emergent nephrotoxicity). Decreased age and CYP3A5*1/*1 genotype were independently associated with subtherapeutic tacrolimus trough concentrations while CYP3A5*1*3 or CYP3A5*3/*3 genotypes, myeloablative allogeneic HSCT conditioning regimen (MAC) and increased weight were independently associated with supratherapeutic tacrolimus trough concentrations. Future lines of prospective research inquiry are warranted to use both germline genetic and clinical data to develop precision dosing tools that will optimize both tacrolimus dosing and clinical outcomes among adult HSCT patients.

Exploration of symptom experience in kidney transplant recipients based on symptoms experience model

PURPOSE

Kidney transplant recipients suffer from a variety of symptoms, and symptom management is crucial in improving their quality of life (QOL). Accordingly, this study aims to identify the symptoms experienced by kidney transplant recipients and examine the relationship amongst antecedents, symptom experience and QOL of recipients in China.

METHODS

A total of 300 kidney transplant recipients were investigated in one of the most first-rate hospitals in China by asking them to fill out a self-designed general questionnaire, the Symptom Experience Scale, the Sense of Coherence Scale (Chinese version), the Revised Life Orientation Test (Chinese version) and the 36-item Short Form Health Survey (Chinese version).

RESULTS

Kidney transplant recipients experienced multiple symptoms that were frequent, severe and bothersome. The final model showed significant consistency with the data. In the QOL model, post-transplant time, complications, immunosuppressive agents and sense of coherence explained 30.7% of the variance of symptom experience. Moreover, habitual residence, economic burden, post-transplant time, kidney function, optimism and symptom experience accounted for 70.6% of the variance on QOL.

CONCLUSIONS

We can explain the relationship between antecedents, symptom experience and QOL amongst Chinese kidney transplant recipients by using Symptoms Experience Model. Clinicians and caregivers can manage the recipient's symptoms during follow-up from psychological, physical and medication management perspectives. Improving sense of coherence, maintaining optimism and managing symptoms are essential for enhancing QOL.

Recent Topics on The Mechanisms of Immunosuppressive Therapy-Related Neurotoxicities

Although transplantation procedures have been developed for patients with end-stage hepatic insufficiency or other diseases, allograft rejection still threatens patient health and lifespan. Over the last few decades, the emergence of immunosuppressive agents such as calcineurin inhibitors (CNIs) and mammalian target of rapamycin (mTOR) inhibitors have strikingly increased graft survival. Unfortunately, immunosuppressive agent-related neurotoxicity commonly occurs in clinical practice, with the majority of neurotoxicity cases caused by CNIs. The possible mechanisms through which CNIs cause neurotoxicity include increasing the permeability or injury of the blood–brain barrier, alterations of mitochondrial function, and alterations in the electrophysiological state. Other immunosuppressants can also induce neuropsychiatric complications. For example, mTOR inhibitors induce seizures, mycophenolate mofetil induces depression and headaches, methotrexate affects the central nervous system, the mouse monoclonal immunoglobulin G2 antibody (used against the cluster of differentiation 3) also induces headaches, and patients using corticosteroids usually experience cognitive alteration. Therapeutic drug monitoring, individual therapy based on pharmacogenetics, and early recognition of symptoms help reduce neurotoxic events considerably. Once neurotoxicity occurs, a reduction in the drug dosage, switching to other immunosuppressants, combination therapy with drugs used to treat the neuropsychiatric manifestation, or blood purification therapy have proven to be effective against neurotoxicity. In this review, we summarize recent topics on the mechanisms of immunosuppressive drug-related neurotoxicity. In addition, information about the neuroprotective effects of several immunosuppressants is also discussed.