Neurotoxicity of calcineurin inhibitors: impact and clinical management

Clinical, histologic, and immunologic signatures of Small Fiber Neuropathy in Systemic Lupus Erythematosus

BACKGROUND AND OBJECTIVES

Systemic Lupus Erythematosus (SLE) often causes damage to small nerve fibers, leading to distressing painful and autonomic symptoms. Despite this, Small Fiber Neuropathy (SFN) remains an underrecognized complication for SLE patients. In this cross-sectional study, we aimed to assess SFN in patients with SLE and to explore its correlations with immunologic disease features and clinical manifestations.

METHODS

We recruited 50 SLE patients (1 male to 12.5 females, aged 20-80 years) reporting painful disturbances. We conducted a comprehensive clinical and neurophysiological evaluation, using Nerve Conduction Studies and Quantitative Sensory Testing. Additionally, we carried out an extensive laboratory assessment of disease-related serological parameters. We also performed a thorough skin biopsy analysis, investigating somatic and autonomic innervation while detecting complement and inflammatory cell infiltrates within the skin.

RESULTS

Out of 50 patients, 19 were diagnosed with SFN, primarily characterized by a non-length-dependent distribution; 7 had a mixed neuropathy, with both large and small fiber involvement. Patients with SFN were younger than patients with a mixed neuropathy (p = .0143); furthermore, they were more likely to have a history of hypocomplementemia (p = .0058) and to be treated with cyclosporine A (p = .0053) compared to patients without neuropathy. However, there were no significant differences in painful and autonomic symptoms between patients with and without SFN.

DISCUSSION

This study highlights the relevant frequency of SFN with a non-length-dependent distribution among SLE patients experiencing painful symptoms. Indeed, SFN emerges as an early manifestation of SLE-related neuropathy and is closely associated with hypocomplementemia, suggesting a potential pathogenic role of the complement system. Moreover, SFN may be influenced by disease-modifying therapies. However, the precise role of SFN in shaping painful and autonomic symptoms in patients with SLE remains to be fully elucidated.

Tacrolimus-associated neurotoxicity isolated to the brainstem: two illustrative cases and a systematic review of the literature

INTRODUCTION

Tacrolimus-associated neurotoxicity (TAN) manifests with wide clinical spectrum, ranging from mild tremors to severe encephalopathy. The isolated involvement of the brainstem is a rarely documented presentation of TAN, and its clinical and diagnostic characteristics are unclear.

METHODS

We report two cases of brainstem-isolated TAN (bi-TAN). Moreover, we performed a systematic review of the literature on bi-TAN and extracted data concerning demographics, clinical characteristics, radiological features, and management. The systematic literature search followed PRISMA guidelines and a pre-defined protocol.

RESULTS

Eleven patients, including our two, were identified (mean age: 41.3 years, ± 18.8; five males, 45%). Speech disturbance was the most common clinical presentation (45%). The mean latency from Tacrolimus initiation to bi-TAN onset was 26 days (± 30.8). Tacrolimus serum level tested above the reference range in three patients (mean: 26.83 ± 5.48). Brain MRI showed T2-FLAIR hyperintensities; three showed restricted diffusion on ADC maps. Neurological symptoms resolved completely in seven patients (63%) after Tacrolimus withdrawal or dose reduction.

CONCLUSIONS

Our findings suggest that bi-TAN could represent a brainstem variant of posterior reversible encephalopathy syndrome. Recognition of bi-TAN as a potential cause of isolated brainstem lesions is crucial to disentangle the diagnostic work-up and ensure prompt withdrawal or reduction of the offending agent.

Unlocking Transplant Tolerance with Biomaterials

For patients suffering from organ failure due to injury or autoimmune disease, allogeneic organ transplantation with chronic immunosuppression is considered the god standard in terms of clinical treatment. However, the true "holy grail" of transplant immunology is operational tolerance, in which the recipient exhibits a sustained lack of alloreactivity toward unencountered antigen presented by the donor graft. This outcome is resultant from critical changes to the phenotype and genotype of the immune repertoire predicated by the activation of specific signaling pathways responsive to soluble and mechanosensitive cues. Biomaterials have emerged as a medium for interfacing with and reprogramming these endogenous pathways toward tolerance in precise, minimally invasive, and spatiotemporally defined manners. By viewing seminal and contemporary breakthroughs in transplant tolerance induction through the lens of biomaterials-mediated immunomodulation strategies-which include intrinsic material immunogenicity, the depot effect, graft coatings, induction and delivery of tolerogenic immune cells, biomimicry of tolerogenic immune cells, and in situ reprogramming-this review emphasizes the stunning diversity of approaches in the field and spotlights exciting future directions for research to come.

Phytochemical Composition, Anti-Inflammatory Property, and Anti-Atopic Effect of Chaetomorpha linum Extract

Utilizing plant-based resources, particularly their by-products, aligns with sustainability principles and circular bioeconomy, contributing to environmental preservation. The therapeutic potential of plant extracts is garnering increasing interest, and this study aimed to demonstrate promising outcomes from an extract obtained from an underutilized plant waste. Chaetomorpha linum, an invasive macroalga found in the Orbetello Lagoon, thrives in eutrophic conditions, forming persistent mats covering approximately 400 hectares since 2005. The biomass of C. linum undergoes mechanical harvesting and is treated as waste, requiring significant human efforts and economic resources-A critical concern for municipalities. Despite posing challenges to local ecosystems, the study identified C. linum as a natural source of bioactive metabolites. Phytochemical characterization revealed lipids, amino acids, and other compounds with potential anti-inflammatory activity in C. linum extract. In vitro assays with LPS-stimulated RAW 264.7 and TNF-α/IFN-γ-stimulated HaCaT cells showed the extract inhibited reactive oxygen species (ROS), nitric oxide (NO), and prostaglandin E2 (PGE2) productions, and reduced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions via NF-κB nuclear translocation, in RAW 264.7 cells. It also reduced chemokines (TARC/CCL17, RANTES/CCL5, MCP-1/CCL2, and IL-8) and the cytokine IL-1β production in HaCaT cells, suggesting potential as a therapeutic candidate for chronic diseases like atopic dermatitis. Finally, in silico studies indicated palmitic acid as a significant contributor to the observed effect. This research not only uncovered the untapped potential of C. linum but also laid the foundation for its integration into the circular bioeconomy, promoting sustainable practices, and innovative applications across various industries.

Conversion From Immediate-Release to Prolonged-Release Tacrolimus in Kidney Transplant Patients With Tremor: A Case Series Study

BACKGROUND/AIM

Tremor is common with tacrolimus treatment and is linked with peak blood drug concentrations. We investigated the effect of switching from immediate-release tacrolimus (IR-TAC) to MeltDose prolonged-release tacrolimus (LCPT) on tremor in kidney transplant recipients experiencing tremor at therapeutic levels of IR-TAC.

METHODS

The Activities of Daily Living Subscale (ADL, range 0-48, lower = better) of the Essential Tremor Rating Scale was used to assess the effect of therapy change on speech, occupational impairment and social activities over a 12-month follow-up period.

RESULTS

The study included 18 patients (mean age = 45.6 y, range 26-73; median (IQR) time from transplant = 1.1 y (0.6-1.5), with baseline IR-TAC trough concentrations (C0) ranging from 4.2 to 9.4 ng/mL (mean C0 = 6.7 ± 1.3 ng/mL). After the switch to LCPT, the mean ADL score improved from baseline 11.2 to 8.4 after 7 to 14 days (an 18% improvement, P < .001). This improvement was sustained after 3 months (ADL score = 5.0, 46% improvement vs baseline), 6 months (ADL score = 4.4, 48% improvement vs baseline), and 12 months (ADL score = 3.6, 63% improvement vs baseline); all P < .001. Despite a 40% reduction in LCPT daily doses (mean -1.9 mg/day compared to IR-TAC), the achieved C0 was constant during the course of the 12-month observation (P = .755). The renal function remained stable after conversion (eGFR 12 months vs baseline = +1.1 mL/min/1.73 m2, 95% CI: -5.6 to +7.9).

CONCLUSION

Conversion to LCPT may alleviate symptom burden and improve daily activities in kidney transplant recipients experiencing tremor within therapeutic IR-TAC concentrations.

Tacrolimus-Induced Neurotoxicity After Transplant: A Literature Review

Tacrolimus, a calcineurin inhibitor, is an immunosuppressant used globally to prevent rejection after organ transplantation. Although it significantly improves outcomes for solid organ transplant patients, it is associated with various side effects such as nephrotoxicity and neurotoxicity. Tacrolimus-induced neurotoxicity is frequently encountered in clinical practice and can present with a variety of symptoms that may occur even at therapeutic levels. Although tacrolimus-induced neurotoxicity is well documented, there is limited literature available on pharmacologic management. Twenty-eight case reports of tacrolimus-induced neurotoxicity were identified and analyzed in addition to other literature including reviews, retrospective studies, and animal model studies. The severity of cases of tacrolimus-induced neurotoxicity reported ranged from mild symptoms that could be managed with symptomatic treatment to conditions such as posterior reversible encephalopathy syndrome and chronic inflammatory demyelinating polyradiculoneuropathy that may require more immediate intervention. This information was utilized in addition to clinical experience to compile potential management options for prevention and treatment of neurotoxic adverse events. This review is limited by the utilization of primarily retrospective studies and case reports. The available literature on the subject is largely narrative and there are no guidelines on treatment of tacrolimus-induced neurotoxicity at the time of this research. This comprehensive review may guide further studies to investigate the pathophysiology of tacrolimus-induced neurotoxicity and to define patient-specific strategies for mitigation or minimization of neurotoxicity. This is especially important given that management of tacrolimus-induced neurotoxicity can include changes to immunosuppression that can result in an increased risk of rejection.

Immunosuppression in solid organ-transplant recipients and impact on nutrition support

A key component to nutrition support is to consider immunosuppressive agents, the interaction with nutrients, and how the side effects of the medications influence nutrition support. The immunosuppression of the solid organ-transplant recipient involves the individualized titration of multiple therapeutic agents to prevent allorecognition and, thus, rejection of the transplanted organ. Induction immunosuppression includes the agents used at the time of transplant to prevent early rejection. Maintenance immunosuppression typically consists of oral medications taken for life. Regular therapeutic monitoring of immunosuppression is necessary to balance the risk of rejection with that of infections and malignancy. In the acute-care setting, multidisciplinary collaboration, including pharmacy and nutrition, is needed to optimize the route of administration, titration, and side effects of immunosuppression. Long-term nutrition management after transplant is also vital to prevent exacerbating adverse effects of immunosuppressive therapies, including diabetes mellitus, hypertension, dyslipidemia, obesity, and bone loss. This review summarizes common immunosuppressive agents currently utilized in solid organ-transplant recipients and factors that may influence decisions on nutrition support.

Characterization of the calcineurin inhibitor pain syndrome in patients undergoing allogeneic hematopoietic cell transplantation

Calcineurin inhibitor pain syndrome (CIPS) is a rare complication of graft-vs-host disease prophylaxis following allogeneic hematopoietic cell transplant (alloHCT). CIPS presents as severe bilateral lower extremity pain, and the incidence, risk factors, and management of CIPS are poorly characterized.This is a single center retrospective study of patients who received tacrolimus (TAC) following alloHCT to describe the characteristics and management of CIPS and compare to a cohort who did not develop CIPS.Fifteen of 585 alloHCT patients (2.6%) developed CIPS at a median of 5 days following TAC initiation and a median level of 10.5 ng/mL. Severe bilateral foot, ankle, or leg pain were the primary symptoms. Patients with CIPS were younger and more frequently received myeloablative conditioning and total body irradiation compared to patients without CIPS. Analgesic regimens included dihydropyridine calcium channel blockers, gabapentinoids, topical diclofenac, and opioids.Clinicians should be aware of this uncommon but severe adverse effect.

Longitudinal modeling of human neuronal aging reveals the contribution of the RCAN1-TFEB pathway to Huntington's disease neurodegeneration

Aging is a common risk factor in neurodegenerative disorders. Investigating neuronal aging in an isogenic background stands to facilitate analysis of the interplay between neuronal aging and neurodegeneration. Here we perform direct neuronal reprogramming of longitudinally collected human fibroblasts to reveal genetic pathways altered at different ages. Comparative transcriptome analysis of longitudinally aged striatal medium spiny neurons (MSNs) in Huntington's disease identified pathways involving RCAN1, a negative regulator of calcineurin. Notably, RCAN1 protein increased with age in reprogrammed MSNs as well as in human postmortem striatum and RCAN1 knockdown rescued patient-derived MSNs of Huntington's disease from degeneration. RCAN1 knockdown enhanced chromatin accessibility of genes involved in longevity and autophagy, mediated through enhanced calcineurin activity, leading to TFEB's nuclear localization by dephosphorylation. Furthermore, G2-115, an analog of glibenclamide with autophagy-enhancing activities, reduced the RCAN1-calcineurin interaction, phenocopying the effect of RCAN1 knockdown. Our results demonstrate that targeting RCAN1 genetically or pharmacologically can increase neuronal resilience in Huntington's disease.

Posterior Reversible Encephalopathy Syndrome in Pediatric Hematopoietic Stem Cell Transplantation with Beta Major Thalassemia: The Association between the PRES Occurrence and Class of Beta Major Thalassemia

INTRODUCTION

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only definitive curative option for β-major thalassemia patients (β-MT). Posterior reversible encephalopathy syndrome (PRES) is a pervasive neurological complication which typically occurs following HSCT. β-MT patients are prone to a higher PRES incidence due to long-term immunosuppression; thus, it is imperative that these patients are closely monitored for PRES after HSCT.

PATIENTS AND METHODS

We included 148 pediatric patients with β-MT who underwent HSCT between March 2015 and August 2022 in Children's Medical Center. Patients in this study were divided into two groups. The association between PRES and class of β-MT and other risk factors were assessed and the overall survival rate was determined.

RESULTS

Fourteen out of 112 patients (12%) with class I and II β-MT developed PRES. However, PRES occurred in 11 out of 36 patients (30.5%) with β-MT-III. Our results indicated that there was a significant association between class III β-MT and the occurrence of (P = .004). Additionally, acute graft-versus-host disease (aGVHD) occurred in 80% and 44.7% of patients in the PRES and non-PRES groups, respectively (P = .001). The results of the Kaplan-Meier analysis revealed that the 5-year overall survival (OS) was 75.6% in the PRES group versus 95% in the non-PRES group, which was statistically significant (P = .001).

CONCLUSION

Based on our results, pediatric β-MT III patients are at a higher risk of developing PRES. Additionally, pediatric β-MT patients with a history of aGVHD, regardless of disease class, are more likely to develop PRES. Considering these results, PRES has a higher chance of being the etiology of symptoms and should be considered more often in these patients.

Transcription factors in the development and treatment of immune disorders

Immune function is highly controlled at the transcriptional level by the binding of transcription factors (TFs) to promoter and enhancer elements. Several TF families play major roles in immune gene expression, including NF-κB, STAT, IRF, AP-1, NRs, and NFAT, which trigger anti-pathogen responses, promote cell differentiation, and maintain immune system homeostasis. Aberrant expression, activation, or sequence of isoforms and variants of these TFs can result in autoimmune and inflammatory diseases as well as hematological and solid tumor cancers. For this reason, TFs have become attractive drug targets, even though most were previously deemed "undruggable" due to their lack of small molecule binding pockets and the presence of intrinsically disordered regions. However, several aspects of TF structure and function can be targeted for therapeutic intervention, such as ligand-binding domains, protein-protein interactions between TFs and with cofactors, TF-DNA binding, TF stability, upstream signaling pathways, and TF expression. In this review, we provide an overview of each of the important TF families, how they function in immunity, and some related diseases they are involved in. Additionally, we discuss the ways of targeting TFs with drugs along with recent research developments in these areas and their clinical applications, followed by the advantages and disadvantages of targeting TFs for the treatment of immune disorders.

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.

Neuroprotective Action of Tacrolimus before and after Onset of Neonatal Hypoxic-Ischaemic Brain Injury in Rats

(1) Background: Neonatal brain injury can lead to permanent neurodevelopmental impairments. Notably, suppressing inflammatory pathways may reduce damage. To determine the role of neuroinflammation in the progression of neonatal brain injury, we investigated the effect of treating neonatal rat pups with the immunosuppressant tacrolimus at two time points: before and after hypoxic-ischaemic (HI)-induced injury. (2) Methods: To induce HI injury, postnatal day (PND) 10 rat pups underwent single carotid artery ligation followed by hypoxia (8% oxygen, 90 min). Pups received daily tacrolimus (or a vehicle) starting either 3 days before HI on PND 7 (pre-HI), or 12 h after HI (post-HI). Four doses were tested: 0.025, 0.05, 0.1 or 0.25 mg/kg/day. Pups were euthanised at PND 17 or PND 50. (3) Results: All tacrolimus doses administered pre-HI significantly reduced brain infarct size and neuronal loss, increased the number of resting microglia and reduced cellular apoptosis (p < 0.05 compared to control). In contrast, only the highest dose of tacrolimus administered post-HI (0.25 mg/kg/day) reduced brain infarct size (p < 0.05). All doses of tacrolimus reduced pup weight compared to the controls. (4) Conclusions: Tacrolimus administration 3 days pre-HI was neuroprotective, likely mediated through neuroinflammatory and cell death pathways. Tacrolimus post-HI may have limited capacity to reduce brain injury, with higher doses increasing rat pup mortality. This work highlights the benefits of targeting neuroinflammation during the acute injurious period. More specific targeting of neuroinflammation, e.g., via T-cells, warrants further investigation.

Unusual Facial Movements (Ictal Blinking, Oculogyric Crises, and Jaw Seizure) in Severe Liver Disease: A Case Series

Background

Seizures are reported in about one-third of patients with severe liver disease in association with acute or chronic liver failure. The majority of the seizures are of focal type. Occasionally generalized tonic-clonic seizures are seen when there is ethanol withdrawal. Not much is known about ictal blinking (IB) in severe liver disease. IB is the rare form of seizures and was reported in severe liver disease recently from this institute. Oculogyric crisis (OGC) is rarely reported in relation to the severe liver disease. OGC was also noted first time in our intensive care unit.

Methods

At the Institute of Liver and Biliary Sciences (ILBS), data on patients with IB and OGC were analyzed from October 2018 to January 2023 (52 months). All the patients had video electroencephalograph (video-EEG) recording after proper permission/consent. The patients were followed up later for the course of the illness.

Results

A total of 16 (12M:4F) patients were seen. Majority 12 (75%) were IB and 3 OGC. EEG was abnormal in nine (75.0%) of IB patients. Brain imaging had nonspecific findings. The outcome was based on the severity and recovery of the underlying liver disease.

Conclusions

Unusual facial movements in the form of IB and OGC are reported, which are most of the time missed. This report highlights the importance of recognition of these events and proper in time management to improve the outcome.

Purtscher-like retinopathy in a patient with systemic tacrolimus vasculopathy

INTRODUCTION

Purtscher-like retinopathy is a rare occlusive retinal microangiopathy, whose pathogenesis has not been totally defined yet. Most frequent cause of Purtscher-like retinopathy is acute pancreatitis, but it may be triggered by other systemic or toxic conditions. We report herein a case of Purtscher-like retinopathy in the context of systemic tacrolimus vasculopathy.

CASE REPORT

A 56-years old male with history of kidney transplant was referred to local emergency room because of a global worsening of health conditions, with fatigue, muscular pain and diuresis contraction. During hospitalization the patient came to our attention for sudden and severe visual acuity impairment in both eyes. Extensive ophthalmological assessment, optical coherence tomography (OCT) and fluorescein angiography (FA) were performed disclosing a marked drop in best corrected visual acuity (BCVA) (20/200 in the right eye and 10/400 in the left eye) caused by a bilateral severe occlusive retinal microangiopathy complicated by diffuse retinal ischaemia and neovascular glaucoma. Muscular biopsy showed a necrotizing myopathy with autoimmune features, as indicated by conspicuous upregulation of MHC-I complex and microangiopathic changes, consistent with tacrolimus toxicity. Tacrolimus administration was interrupted, and intravenous glucocorticoids were administered. The large areas of retinal ischemia and neovascular glaucoma were treated with pan-retinal photocoagulation and intravitreal injections of bevacizumab with complete regression of iris neovascolarization. BCVA measured 20/200 in both eyes at last follow-up visit, 20 months after symptoms onset.

CONCLUSIONS

Purtscher-like retinopathy should be suspected in patients under treatment with calcineurin inhibitors especially in case of sudden and severe bilateral visual impairment.

Delayed-Onset Psychosis Secondary to Tacrolimus Neurotoxicity After Lung Transplant: A Case Report and Systematic Review

BACKGROUND

Tacrolimus is the most common immunosuppressant used after transplant, yet it can result in moderate-to-severe neurotoxicity in up to 32% of patients. Signs of neurotoxicity can vary from mild (tremor or headache) to severe (posterior reversible encephalopathy syndrome or psychosis. Prompt recognition and management is needed to lead to symptom resolution.

OBJECTIVE

The objective of this study is to describe the clinical presentation of tacrolimus-induced psychosis, a type of tacrolimus-inducted neurotoxicity, and distinguish it from other central nervous system disturbances, including delirium.

METHODS AND RESULTS

We present a case of delayed onset tacrolimus-induced psychosis with focus on unique clinical features and management strategies. We conducted a systematic review of cases of tacrolimus-induced psychosis using the PubMed database and included 15 manuscripts in our review.

CONCLUSIONS

Tacrolimus-induced psychosis is a unique presentation of tacrolimus-related neurotoxicity and can present without the cardinal symptoms of delirium. The data on isolated psychotic symptoms are limited with current literature focusing on more common presentations of tacrolimus-induced neurotoxicity, such as delirium and tremor. Development of psychosis can occur later in the treatment course and at normal tacrolimus serum levels. It can improve with antipsychotic therapies, but primary management should include cross-titration to an alternate immunosuppressant regimen.

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.

Neurocognitive deficits may not resolve following pediatric kidney transplantation

BACKGROUND

Pediatric chronic kidney disease (CKD) patients are at risk for cognitive deficits with worsening disease progression. Limited, existing cross-sectional studies suggest that cognitive deficits may improve following kidney transplantation. We sought to assess cognitive performance in relationship to kidney transplantation and kidney-specific medical variables in a sample of pediatric kidney transplant patients who provided cross-sectional and longitudinal observations.

METHODS

A retrospective chart review was conducted in patients who completed pre- and/or post-transplant neurocognitive testing at the University of Iowa from 2015-2021. Cognitive outcomes were investigated with developmentally appropriate, standardized measures. Mixed linear models estimated the impact of transplant status on cognitive function (z-scores). Subsequent post-hoc t-tests on change scores were limited to patients who had provided pre- and post-transplant assessments.

RESULTS

Thirty eight patients underwent cognitive assessments: 10 had both pre- and post-transplant cognitive assessments, 11 had pre-transplant assessments only, and 17 had post-transplant data only. Post-transplant status was associated with significantly lower full-scale IQ and slower processing speed compared to pre-transplant status (estimate = -0.32, 95% confidence interval [CI] = -0.52: -0.12; estimate = -0.86, CI = -1.17: -0.55, respectively). Post-hoc analyses confirmed results from the mixed models (FSIQ change score = -0.34, 95% CI = -0.56: -0.12; processing speed change score = -0.98, CI = -1.28: -0.68). Finally, being ≥80 months old at transplant was associated with substantially lower FSIQ compared to being <80 months (estimate = -1.25, 95% CI = -1.94: -0.56).

CONCLUSIONS

Our results highlight the importance of monitoring cognitive function following pediatric kidney transplant and identify older transplant age as a risk factor for cognitive deficits.

Cyclosporine A induces hepatotoxicity in zebrafish larvae via upregulating oxidative stress

As a powerful immunosuppressant, cyclosporine A (CsA) is widely used clinically. However, it has been found to have many side effects including nephrotoxicity and neurotoxicity. Despite this, some patients cannot avoid using CsA during pregnancy and this can be detrimental to both the patient and the foetus. This study used zebrafish as a model animal to evaluate the hepatotoxic effects of CsA in zebrafish embryos. Zebrafish embryos cultured at 72 post-fertilization (hpf) were exposed to three concentrations of CsA at 2.5 mg/L, 5 mg/L, and 10 mg/L for 72 h. Liver developmental defects, smaller or missing swim bladder, slower heart rate, reduced body length, and delayed yolk sac absorption were observed. The level of oxidative stress (ROS) increased with the increase of CsA concentration. The indicators of related oxidative stress kinase activities including malondialdehyde (MDA), catalase (CAT) and SOD, all appeared to significantly increased. The use of astaxanthin (ATX) to inhibit oxidative stress was found to be useful for rescuing zebrafish hepatic development defects. Therefore, our results suggest that CsA induces zebrafish embryonic hepatic development defects by activating the oxidative stress. The study of CsA-induced hepatic development defects of zebrafish embryos is helpful for clinical evaluation of the safety of CsA and enables the search for new use without side effects.

Seizures in patients with kidney diseases: a neglected problem?

Nephrologists may encounter many systemic problems in their patients, including involvement of the neurological system and the development of seizures. Seizures are defined as abnormal neurological functions that cause overstimulation of neurons in the cerebral cortex or limbic system. Seizures may be focal or generalized depending on their origin and may have tonic, clonic, tonic-clonic or myoclonic character depending on the level of involvement of the motor movements. Patients with kidney disease may develop seizures due to etiologies seen in the general population (such as intracranial bleeding, cerebrovascular events, tumors, infections and intoxications) or due to kidney-related etiologies (such as uremic encephalopathy, dialysis disequilibrium syndrome and hyponatremia). Management of seizures in kidney patients is challenging for proper determination of the type and dosage of antiepileptic drugs due to varying renal clearances. This review covers the major causes of new-onset seizures in patients with acute kidney injury, electrolyte imbalances, chronic kidney disease, dialysis, renal transplantation or hypertension, and the available management approaches.

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.

Quality of Life Outcomes and Associated Symptoms Reported by Lung Transplant Recipients Amidst COVID-19 Pandemic: Applying a Novel Assessment Tool

BACKGROUND

There are 2 main aims of lung transplantation for people with end-stage lung disease: (1) to extend life and (2) to improve its quality. Much consideration is given to how to support the longevity and functioning of the allograft, though less robust studies have been done on the quality of the recipients' lives. With an interest in providing compassionate and holistic patient-centered care, it is vital that the treatment providers accurately understand their patients' lived experience. This study aimed to describe the health-related quality of life experiences of lung transplant recipients. An interest was held for where patients may struggle, thus informing where support might be needed to achieve the best possible outcomes.

METHODS

This single-center study used a validated Lung Transplant Quality of Life questionnaire, which was sent in autumn of 2020 to all of the lung transplant recipients (n = 581) under the care of Columbia University Irving Medical Center (New York, NY).

RESULTS

"Anxiety/Depression" had the highest concentration of struggle responses, followed closely by "Pulmonary Symptoms" and "Neuromuscular Symptoms." "Neuromuscular Problems" and "Sexual Problems" had the highest percentage of struggle responses. As the struggles increased, the overall quality of life rating dropped proportionately. There was no correlation between the overall quality of life and graft dysfunction, age, or time out from transplant date. All of the domains held an average rating of "Satisfactory," except "Treatment Burden," which was rated as "Favorable." Those ratings dropped for the cohort of patients who died during the study period.

CONCLUSIONS

With the goal of providing comprehensive care at the forefront of transplant priorities, we found the newly developed questionnaire invaluable in targeting areas for quality improvements, mostly notably respecting recipient mental health.

Status Epilepticus in Post-Transplantation Hyperammonemia Involves Careful Metabolic Management

Hyperammonemia is a condition that may result after solid organ transplantation, particularly lung transplantation. However, it is very uncommon for this presentation to occur more than 30 days post-transplantation. Hyperammonemia and the resulting encephalopathy typically manifest with altered sensorium, a clinical situation which is not often included in the differential diagnosis of presumed nonconvulsive status epilepticus (NCSE). Seizures are common among this subset of patients with hyperammonemia and may be refractory to traditional treatments. Evidence of elevated intracranial pressure by invasive monitoring and neuroimaging findings of diffuse cerebral edema are commonly reported. Here we examine the therapeutic importance of identifying the specific cause of hyperammonemic encephalopathy, a condition which may result in status epilepticus and ultimately cerebral edema or even brain death.

Ictal Blinking in Hepatic Encephalopathy Pre- and Post-Liver Transplant: Report of Eight Patients

Objective  Seizures are reported in 20 to 30% of cases with chronic liver disease in association with hepatic encephalopathy. Majority of these are focal seizures. Ictal blinking is reported first time in these patients pre- and post-liver transplant. Methods  From November 2018 to October 2021, retrospective data was analyzed in patients with end-stage liver disease and hepatic encephalopathy, both pre- and post-liver transplant. Results  Eight patients had ictal blinking, four were pre-transplant and four post-transplant. Five patients (four after liver transplant and one pre-transplant) were seizure free, three died of liver disease and multiorgan dysfunction, and one did not follow-up. Conclusion  Ictal blinking in relation to liver disease and hepatic encephalopathy is reported, often missed and requires short duration antiepileptic medications.

Pediatric Tacrolimus-Induced Reversible Cerebral Vasoconstriction Syndrome after Heart Transplantation

Reversible cerebral vasoconstriction syndrome (RCVS) is a rare post-organ transplantation complication. While uncommon, complications of post-transplant RCVS can be devastating, with sequelae including ischemic or hemorrhagic stroke and potential significant neurological morbidity. There is a paucity of literature on tacrolimus-mediated RCVS, particularly in the pediatric population. To date, only five case reports have been published, with the youngest patient being 15 years of age. We report the youngest case to date of post-heart transplant tacrolimus-induced RCVS in a 6-year-old male. The present case highlights the necessity of urgent imaging in suspected cases of RCVS, the potential diagnostic challenges surrounding the etiology of headache, the benefits of treating underlying cerebral vasospasm, and the importance of rapid discontinuation of the offending agent for the remission of symptoms and prevention of long-term sequelae.

Hearing Impairments as an Overlooked Condition in Kidney Transplant Recipients

It is not known whether hearing disorders improves with kidney transplantation. One of the neurotoxic effects of immunosuppressive drugs may be unrecognized hearing loss. In this study, our aim was to evaluate the hearing disorders in kidney transplant patients. Hearing problems in 46 kidney transplant patients [eGFR ≥ 60 ml/min/1.73 m² (30 Tacrolimus, 16 mTOR inhibitor users)], 23 hemodialysis patients, and 20 healthy controls were evaluated with a questionnaire and high-frequency audiometry. More than half (58.7%) of the transplant patients had at least one hearing problem. Hearing loss was observed in 50%, 60.9% and 76.1% of the transplant patients at 8,000, 16,000 and 20,000 Hz. Hearing thresholds of transplant and hemodialysis patients increased from 4,000 to 20,000 Hz and was higher than that of controls. Hearing thresholds were higher at 1,000–2,000 Hz in patients using tacrolimus and at 16,000–20,000 Hz in patients using mTOR inhibitor. No correlation was found between hearing threshold and blood tacrolimus or mTOR inhibitor levels. Most kidney transplant and hemodialysis patients have hearing loss at higher frequencies than medium frequencies. Hearing loss in chronic kidney patients is likely to be permanent and kidney transplantation may not improve hearing problems. Hearing problems may be more pronounced at medium frequencies in patients receiving tacrolimus but at higher frequencies in patients receiving mTOR inhibitors.

Therapeutic drug level of tacrolimus causing intracranial hemorrhage in a patient with renal transplant

Tacrolimus is used in solid organ transplant patients to prevent rejection, and no case of intracerebral hemorrhage (ICH) has been reported till date. We report a case of 31‐year‐old man with diabetes and hypertension for ten years who had a renal transplant four years back; diagnosed with tacrolimus‐induced ICH.

Transcranial sonography depicts a larger substantia nigra echogenic area in renal transplant patients on calcineurin inhibitors than on rapamycin

BACKGROUND

After kidney transplantation neurologic manifestations may develop, including Parkinson's disease (PD). An enlarged substantia nigra (SN) by transcranial sonography has been recognized as a marker of PD.

METHODS

In renal transplant recipients (RTRs = 95) and controls (n = 20), measurement of mesencephalon, SN, third ventricle, spleen and carotid intima-media thickness (cIMT) and middle cerebral artery (MCA), kidney and spleen arteries Doppler resistive index (RI) were performed.

RESULTS

RTRs had larger SN, third ventricle and cIMT and higher renal RI than controls. The SN was larger in the CNIs group than in controls and rapamycin group, while the third ventricle was similar between patients but larger than in controls. In RTRs, SN showed a direct linear correlation with spleen and the third ventricle with age, cIMT and RI of the MCA, kidney and spleen. In CNIs group the SN correlated positively with age and cIMT, while the third ventricle reproduced RTRs correlations. Rapamycin group showed a direct linear relationship between the third ventricle and age and RI of the MCA, kidney and spleen; SN showed no correlations.

CONCLUSION

RTRs on CNIs present a larger SN area than on rapamycin, probably due to the antiproliferative effect of rapamycin. This finding might be relevant when interpreting TCS in RTRs.

Tacrolimus Combined with Corticosteroids Improved the Outcome of CIDP Patients with Autoantibodies Against Paranodal Proteins

PURPOSE

To investigate the response of tacrolimus to chronic inflammatory demyelinating polyneuropathy (CIDP) with autoantibodies against paranodal proteins, including neurofascin-155 (NF155), contactin-1 (CNTN1) and contactin-associated protein 1 (Caspr1).

METHODS

We retrospectively reviewed all CIDP patients who carried anti-NF155, CNTN1 and Caspr1 antibodies and were treated with tacrolimus at Tongji hospital from Jan 2018 to Apr 2021.

RESULTS

There were 58 patients with CIDP and only 9 patients had autoantibodies against paranodal proteins (17.2%). Five of the 9 patients received tacrolimus treatment with an initial dose of 2-3 mg once daily. One patient with anti-CNTN1 antibody started tacrolimus and corticosteroid treatment, at the first episode and eventually achieved full clinical remission without relapse. Four patients with anti-NF155 or -Caspr1 antibodies experienced relapse during corticosteroids tapering. Then, they were given oral tacrolimus and presented with clinical improvement. During follow-up, only one patient developed worsening weakness due to unreasonable tacrolimus discontinuation. Moreover, 3 patients were successfully withdrawn from corticosteroids and 2 patients took corticosteroids at low maintenance dose (10mg/d) after tacrolimus treatment. No severe adverse events were observed in all the patients.

CONCLUSION

Patients with autoantibodies against paranodal proteins had a better long-term outcome after adding tacrolimus. Combination therapy with corticosteroids and tacrolimus may be an effective therapeutic regimen.

Structural brain abnormalities in children and young adults with severe chronic kidney disease

BACKGROUND

The pathophysiology of neurological dysfunction in severe chronic kidney disease (CKD) in children and young adults is largely unknown. We aimed to investigate brain volumes and white matter integrity in this population and explore brain structure under different treatment modalities.

METHODS

This cross-sectional study includes 24 patients with severe CKD (eGFR < 30) aged 8-30 years (median = 18.5, range = 9.1-30.5) on different therapy modalities (pre-dialysis, n = 7; dialysis, n = 7; transplanted, n = 10) and 21 healthy controls matched for age, sex, and parental educational level. Neuroimaging targeted brain volume using volumetric analysis on T1 scans and white matter integrity with tract-based spatial statistics and voxel-wise regression on diffusion tensor imaging (DTI) data.

RESULTS

CKD patients had lower white matter integrity in a widespread cluster of primarily distal white matter tracts compared to healthy controls. Furthermore, CKD patients had smaller volume of the nucleus accumbens relative to healthy controls, while no evidence was found for abnormal volumes of gray and white matter or other subcortical structures. Longer time since successful transplantation was related to lower white matter integrity. Exploratory analyses comparing treatment subgroups suggest lower white matter integrity and smaller volume of the nucleus accumbens in dialysis and transplanted patients relative to healthy controls.

CONCLUSIONS

Young CKD patients seem at risk for widespread disruption of white matter integrity and to some extent smaller subcortical volume (i.e., nucleus accumbens). Especially patients on dialysis therapy and patients who received a kidney transplant may be at risk for disruption of white matter integrity and smaller volume of the nucleus accumbens.

Bioavailability of once-daily tacrolimus formulations used in clinical practice in the management of De Novo kidney transplant recipients: the better study

Multicenter, prospective, observational study to compare the relative bioavailability of once‐daily tacrolimus formulations in de novo kidney transplant recipients. De novo kidney transplant recipients who started a tacrolimus‐based regimen were included 14 days post‐transplant and followed up for 6 months. Data from 218 participants were evaluated: 129 in the LCPT group (Envarsus) and 89 in the PR‐Tac (Advagraf) group. Patients in the LCPT group exhibited higher relative bioavailability (C_min /total daily dose [TDD]) vs. PR‐Tac (61% increase; P < .001) with similar C_min and 30% lower TDD levels (P < .0001). The incidence of treatment failure was 3.9% in the LCPT group and 9.0% in the PR‐Tac group (P = .117). Study discontinuation rates were 6.2% in the LCPT group and 12.4% in the PR‐Tac group (P = .113). Adverse events, renal function and other complications were comparable between groups. The median accumulated dose of tacrolimus in the LCPT group from day 14 to month 6 was 889 mg. Compared to PR‐Tac, LCPT showed higher relative bioavailability, similar effectiveness at preventing allograft rejection, comparable effect on renal function, safety, adherence, treatment failure and premature discontinuation rates.

Tacrolimus-induced neurotoxicity from bipolar disorder to status epilepticus under the therapeutic serum level: a case report

BACKGROUND

Tacrolimus is a macrolide immunosuppressant widely used to prevent rejection after solid organ transplantation. In general, adverse events of tacrolimus occur more often as the concentration of tacrolimus in the blood increases. We report the case of a 39-year-old man who developed a variety of adverse events despite in the therapeutic level of tacrolimus in the blood.

CASE PRESENTATION

A 39-year-old man underwent liver transplantation for liver cirrhosis due to alcoholic liver disease. The postoperative immunosuppressant consisted of tacrolimus (5 mg) and mycophenolate (500 mg) twice daily. Five months after taking tacrolimus, he presented with talkativeness, which gradually worsened. Brain magnetic resonance imaging performed 10 months after tacrolimus administration revealed a hyperintense lesion affecting the middle of the pontine tegmentum on T2WI. The blood concentration of tacrolimus was 7.2 ng/mL (therapeutic range 5-20 ng/mL). After 21 months, he exhibited postural tremor in both the hands. Twenty-four months after taking tacrolimus, he showed drowsy mentality, intention tremor, and dysdiadochokinesia. Electroencephalography presented generalized high-voltage rhythmic delta waves; therefore, tacrolimus was discontinued in suspicion of tacrolimus-induced neurotoxicity, and anticonvulsive treatment was started. The level of consciousness gradually improved, and the patient was able to walk independently with mild ataxia.

CONCLUSION

This case shows that tacrolimus-induced neurotoxicity can occur even at normal concentrations. Therefore, if a patient taking tacrolimus exhibits psychiatric or neurologic symptoms, neurotoxicity should be considered even when the blood tacrolimus is within the therapeutic range.

Acute Graft-Versus-Host Disease, Infections, Vascular Events and Drug Toxicities Affecting the Central Nervous System

Allogeneic hematopoietic cell transplantation (allo-HCT) is a curative therapy for patients with hematological malignancies. Acute Graft versus host diseases (GVHD) is a major immune mediated side effect of allo-HCT that can affect the central nervous system (CNS) in addition to post-allo-HCT vascular events, drug toxicity or infections. Here we summarize and discuss recent preclinical data on the CNS as a target of acute GVHD and the known mechanisms contributing to neurotoxicity with a focus on microglia and T cells. We also discuss open questions in the field and place the findings made in mouse models in a clinical context. While in mice the neurological deficits can be assessed in a controlled fashion, in patients the etiology of the CNS damage is difficult to attribute to acute GVHD versus infections, vascular events, and drug-induced toxicity. Ultimately, we discuss novel therapies for GVHD of the CNS. Our understanding of the biological mechanisms that lead to neurotoxicity after allo-HCT increased over the last decade. This review provides insights into CNS manifestations of GVHD versus other etiologies of CNS damage in mice and patients.

Guillain-Barré Syndrome after Lung Transplantation in the Immediate Postoperative Period: Case Report

A 58-year-old man, incapable of maintaining oxygen saturation with mechanical ventilation, was admitted to our hospital for veno-venous extracorporeal membrane oxygenation (ECMO) treatment. He was diagnosed with acute respiratory distress syndrome (ARDS) due to influenza A pneumonia. His condition stabilized with antibiotics and steroid administration, but weaning from ECMO failed due to post-infectious pulmonary sequelae. On day 84 after admission, he underwent bilateral lung transplantation. In the postoperative phase, he did not regain consciousness even after discontinuation of sedatives for 3 days. However, spontaneous pupillary reflex and eye movements were preserved, while communication and upper and lower limb movements were affected. The nerve conduction study was diagnostic of Guillain-Barré syndrome. He was managed with intravenous immunoglobulins and plasmapheresis. Mild recovery of the facial muscles was seen, but he died 24 days post-surgery due to progressive ARDS and sepsis.

Sustained Intra-Articular Release and Biocompatibility of Tacrolimus (FK506) Loaded Monospheres Composed of [PDLA-PEG1000]-b-[PLLA] Multi-Block Copolymers in Healthy Horse Joints

There is an increasing interest in controlled release systems for local therapy in the treatment of human and equine joint diseases, aiming for optimal intra-articular concentrations with no systemic side effects. In this study, the intra-articular tolerability and suitability for local and sustained release of tacrolimus (FK506) from monospheres composed of [PDLA-PEG₁₀₀₀]-b-PLLA multiblock copolymers were investigated. Unloaded and tacrolimus-loaded (18.4 mg tacrolimus/joint) monospheres were injected into the joints of six healthy horses, with saline and hyaluronic acid (HA) in the contralateral joints as controls. Blood and synovial fluid were analysed for the tacrolimus concentration and biomarkers for inflammation and cartilage metabolism. After an initial burst release, sustained intra-articular tacrolimus concentrations (>20 ng/mL) were observed during the 42 days follow-up. Whole-blood tacrolimus levels were below the detectable level (<0.5 ng/mL). A transient inflammatory reaction was observed for all substances, evidenced by increases of the synovial fluid white blood cell count and total protein. Prostaglandin and glycosaminoglycan release were increased in joints injected with unloaded monospheres, which was mitigated by tacrolimus. Both tacrolimus-loaded monospheres and HA transiently increased the concentration of collagen II cleavage products (C2C). A histologic evaluation of the joints at the endpoint showed no pathological changes in any of the conditions. Together, these results indicate the good biocompatibility of intra-articular applied tacrolimus-loaded monospheres combined with prolonged local drug release while minimising the risk of systemic side effects. Further evaluation in a clinical setting is needed to determine if tacrolimus-loaded monospheres can be beneficial in the treatment of inflammatory joint diseases in humans and animals.

Cost-effectiveness of once-daily vs twice-daily tacrolimus among Hispanic and Black kidney transplant recipients

BACKGROUND: Tacrolimus is a first-line immunosuppressive therapy to prevent rejection and graft failure in kidney transplant recipients. Once-daily extended-release tacrolimus tablets (LCPT) have been shown to be efficacious, particularly for Hispanic and Black patient subpopulations who are rapid metabolizers, but is more costly than twice-daily immediate-release tacrolimus (IR-Tac). OBJECTIVE: To evaluate the cost-effectiveness of LCPT during the first year of treatment vs IR-Tac in kidney transplant recipients who are Hispanic or Black. METHODS: A decision analytic model from a US payer perspective was developed using (1) subgroup outcomes data pooled from two phase 3 clinical trials that compared LCPT and IR-Tac, and (2) direct costs from real-world data sources (ie, costs of LCPT and IR-Tac treatments, biopsy-proven acute rejection, treatment-related serious adverse events [SAEs], graft failure, and consequent dialysis). The primary outcome was cost per successfully treated patient, defined as having a functioning graft after 1 year and without treatment-related SAEs. Probabilistic sensitivity analyses established distributions for cost and outcomes estimates, and a series of one-way sensitivity analyses identified parameters that had the most effect on results. RESULTS: Total overall cost for the Hispanic group was $14,765 for LCPT and $12,416 for IR-Tac, and total cost in the Black group was $16,626 for LCPT and $9,871 for IR-Tac. Total overall effectiveness of LCPT and IR-Tac was 88.32% and 84.75% in the Hispanic group and 93.24% and 85.78% in the Black group, respectively. The incremental cost-effectiveness ratio (ICER) for using LCPT over IR-Tac during the first year of treatment in the Hispanic group was $65,643 per additional successfully treated patient. The ICER for the Black group was $90,458. The single parameter having the most impact on results in both groups was the probability of a treatment-related SAE in IR-Tac, which accounted for 49% of variation in results in the Hispanic group and 46% in the Black group. CONCLUSIONS: Overall results for both groups show that LCPT is incrementally more costly and more effective compared with IR-Tac, indicating a trade-off scenario. LCPT is a cost-effective strategy if a decision makers' willingness to pay for 1 additional successfully treated patient exceeds the ICER and must be weighed against the costs of graft loss, continuing dialysis, and potential retransplant. This study provides a foundation for further research to update and expand inputs as more data become available to improve real-world relevance and decision making. DISCLOSURES: This study was funded by Veloxis Pharmaceuticals, Inc., which provided clinical trial file data and nonbinding feedback on the model structure, data interpretation, clinical expertise, manuscript review, and areas of publication interest (ie, managed care). Hurwitz, Grizzle, Villa Zapata, and Malone received grant funding from Veloxis Pharmaceuticals, Inc., through University of Arizona to conduct research and analysis for this study. Tyler is employed by Veloxis Pharmaceuticals, Inc. Some of the data reported and used in this research were available from the US Renal Data System, the US Bureau of Labor Statistics, and the Agency for Healthcare Research and Quality's Healthcare Cost and Utility Project. The interpretation and reporting of these data are the responsibility of the authors and in no way should be seen as an official policy or interpretation of the US government.

A novel Huntington's disease mouse model to assess the role of neuroinflammation on disease progression and to develop human cell therapies

Huntington's disease (HD) is a fatal autosomal-dominant neurodegenerative disease caused by a trinucleotide CAG repeat expansion of the huntingtin gene (HTT) that affects 1 in every 10 000 individuals in the United States. Our lab developed a novel immune deficient HD mouse strain, the YACNSG, from a commonly used line, the YAC128 mouse, to enable transplantation studies using engineered human cells in addition to studying the impact of the immune system on disease progression. The primary goal of this project was to characterize this novel immune deQficient HD mouse model, using behavioral assays and histology to compare this new model to the immune competent YAC128 and immune deficient mice that had engraftment of a human immune system. Flow cytometry was used to confirm that the YACNSG strain lacked immune cells, and in vivo imaging was used to assess human mesenchymal stem/stromal cell (MSC) retention compared with a commonly used immune deficient line, the NSG mouse. We found that YACNSG were able to retain human MSCs longer than the immune competent YAC128 mice. We performed behavioral assessments starting at 4 months of age and continued testing monthly until 12 months on the accelerod and in the open field. At 12 months, brains were isolated and evaluated using immunohistochemistry for striatal volume. Results from these studies suggest that the novel immune deficient YACNSG strain of mice could provide a good model for human stem-cell based therapies and that the immune system appears to play an important role in the pathology of HD.

Neurocognitive Impairment After Hematopoietic Stem Cell Transplant for Hematologic Malignancies: Phenotype and Mechanisms

Hematopoietic stem cell transplant (HSCT) plays a central role in the treatment of hematologic cancers. With the increasing survival of patients after HSCT, survivorship issues experienced by this population have become an important outcome. Cognitive impairment is an established sequela of HSCT, with studies to date establishing its presence, associated risk factors, and clinical phenotype. There are multiple potential contributors to cognitive impairment after HSCT. Efforts are ongoing to further characterize its clinical phenotype, associated biomarkers, and biologic underpinnings. A fundamental knowledge of post-HSCT cognitive impairment is of value for all clinicians who interface with this population, and further academic efforts are needed to more fully understand the impact of this cancer treatment on brain health. IMPLICATIONS FOR PRACTICE: As survival outcomes after hematopoietic stem cell transplant (HSCT) improve, an awareness of the post-treatment challenges faced by this population has become central to its care. HSCT can have a sustained and broad impact on brain health, causing cognitive dysfunction, fatigue, disturbed mood, and sleep. In affected patients, autonomy, return to work, relationships, and quality of life may all be affected. A fundamental fluency in this area is important for clinicians interfacing with HSCT survivors, facilitating the identification and management of cognitive dysfunction and concurrent symptom clusters, and stimulating interest in these sequelae as areas for future clinical research.

Calcineurin inhibitors suppress acute graft-versus-host disease via NFAT-independent inhibition of T cell receptor signaling

Inhibitors of calcineurin phosphatase activity (CNIs) such as cyclosporin A (CsA) are widely used to treat tissue transplant rejection and acute graft-versus-host disease (aGVHD), for which inhibition of gene expression dependent on nuclear factor of activated T cells (NFAT) is the mechanistic paradigm. We recently reported that CNIs inhibit TCR-proximal signaling by preventing calcineurin-mediated dephosphorylation of LckS59, an inhibitory modification, raising the possibility of another mechanism by which CNIs suppress immune responses. Here we used T cells from mice that express LckS59A, which cannot accept a phosphate at residue 59, to initiate aGVHD. Although CsA inhibited NFAT-dependent gene upregulation in allo-aggressive T cells expressing either LckWT or LckS59A, it was ineffective in treating disease when the T cells expressed LckS59A. Two important NFAT-independent T cell functions were found to be CsA-resistant in LckS59A T cells: upregulation of the cytolytic protein perforin in tissue-infiltrating CD8+ T cells and antigen-specific T/DC adhesion and clustering in lymph nodes. These results demonstrate that effective treatment of aGVHD by CsA requires NFAT-independent inhibition of TCR signaling. Given that NFATs are widely expressed and off-target effects are a major limitation in CNI use, it is possible that targeting TCR-associated calcineurin directly may provide effective therapies with less toxicity.

AAAPT Diagnostic Criteria for Acute Neuropathic Pain

OBJECTIVE

Acute neuropathic pain is a significant diagnostic challenge, and it is closely related to our understanding of both acute pain and neuropathic pain. Diagnostic criteria for acute neuropathic pain should reflect our mechanistic understanding and provide a framework for research on and treatment of these complex pain conditions.

METHODS

The Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership with the U.S. Food and Drug Administration (FDA), the American Pain Society (APS), and the American Academy of Pain Medicine (AAPM) collaborated to develop the ACTTION-APS-AAPM Pain Taxonomy (AAAPT) for acute pain. A working group of experts in research and clinical management of neuropathic pain was convened. Group members used literature review and expert opinion to develop diagnostic criteria for acute neuropathic pain, as well as three specific examples of acute neuropathic pain conditions, using the five dimensions of the AAAPT classification of acute pain.

RESULTS

AAAPT diagnostic criteria for acute neuropathic pain are presented. Application of these criteria to three specific conditions (pain related to herpes zoster, chemotherapy, and limb amputation) illustrates the spectrum of acute neuropathic pain and highlights unique features of each condition.

CONCLUSIONS

The proposed AAAPT diagnostic criteria for acute neuropathic pain can be applied to various acute neuropathic pain conditions. Both the general and condition-specific criteria may guide future research, assessment, and management of acute neuropathic pain.

Neurological complications after living-donor liver transplantation in children

AIM

Liver transplantation (LT) has been used as a definitive management for children with end-stage liver disease or acute liver failure. Living-donor LT (LDLT) has been a common type of LT performed in Asian countries, including Japan, where deceased donors are rarely available. However, the neurological complications (NCs) associated with LDLT remain unknown. The purpose of this study was to clarify the characteristics of NCs in children after LDLT.

METHODS

This study is a retrospective observational study carried out at a tertiary children's hospital in Japan. We studied children who had undergone LDLT between January 2001 and January 2020.

RESULTS

We examined 602 cases of LT, of which 559 were LDLT cases (92.9%). NCs after LT were present in 21 cases (3.8%). The most common neurological symptoms were seizure (n = 17), whereas disturbance of consciousness without seizure was observed in four cases. The frequency of NCs for each of the indications was 12.2% for fulminant hepatic failure, 6.5% for metabolic liver disease, and 0.7% for cholestatic liver disease.

INTERPRETATION

We report the characteristics of NCs after LDLT in children. The frequency of NCs after LT was high in cases of fulminant hepatic failure and metabolic diseases, who might have had neurological symptoms or impaired consciousness before LT.

Optimization of de novo belatacept-based immunosuppression administered to renal transplant recipients

Kidney transplant recipients administered belatacept-based maintenance immunosuppression present with a more favorable metabolic profile, reduced incidence of de novo donor-specific antibodies (DSAs), and improved renal function and long-term patient/graft survival relative to individuals receiving calcineurin inhibitor (CNI)-based immunosuppression. However, the rates and severity of acute rejection (AR) are greater with the approved belatacept-based regimen than with CNI-based immunosuppression. Although these early co-stimulation blockade-resistant rejections are typically steroid sensitive, the higher rate of cellular AR has led many transplant centers to adopt immunosuppressive regimens that differ from the approved label. This article summarizes the available data on these alternative de novo belatacept-based maintenance regimens. Steroid-sparing, belatacept-based immunosuppression (following T cell-depleting induction therapy) has been shown to yield AR rates comparable to those seen with CNI-based regimens. Concomitant treatment with belatacept plus a mammalian target of rapamycin inhibitor (mTORi; sirolimus or everolimus) has yielded AR rates ranging from 0 to 4%. Because the optimal induction agent and number of induction doses; blood levels of mTORi; and dose, duration, and use of corticosteroids have yet to be determined, larger prospective clinical trials are needed to establish the optimal alternative belatacept-based regimen for minimizing early cellular AR occurrence.

Functional Improvement of Tacrolimus-Induced Parkinsonism With Amantadine After Liver Transplantation: A Case Report

ABSTRACT

Drug-induced parkinsonism is the most common type of drug-induced movement disorder, whose symptoms can decrease patient quality of life and reduce medication compliance. Tacrolimus is a routinely used immunosuppressant agent after liver transplantation, with a well-known neurotoxic profile. There have been rare reports of tacrolimus-induced parkinsonism, but its pharmacologic management and functional impact remain poorly characterized in the literature. We present a case of tacrolimus-induced parkinsonism in a 62-year-old man after a liver transplant, resulting in significant neurologic impairments and multiple barriers to hospital discharge. His tremor, rigidity, bradykinesia, gait dysfunction, dysphonia, and dysphagia significantly improved after starting low-dose amantadine, with increased functional independence that allowed for a safe discharge. This is the first case in the literature detailing tacrolimus-induced parkinsonism's functional impairments improving with amantadine monotherapy.

Effect of Mycophenolate Mofetil Therapy on Recurrence of Hepatocellular Carcinoma after Liver Transplantation: A Population-Based Cohort Study

Hepatocellular carcinoma (HCC) recurrence after liver transplantation is associated with immunosuppressants. However, the appropriate immunosuppressant for HCC recipients is still debated. Data for this nationwide population-based cohort study were extracted from the National Health Insurance Research Database of Taiwan. A total of 1250 liver transplant recipients (LTRs) with HCC were included. We analyzed the risk factors for post-transplant HCC recurrences. Cumulative defined daily dose (cDDD) represented the exposure duration and was calculated as the amount of dispensed defined daily dose (DDD) of mycophenolate mofetil (MMF). The dosage effects of MMF on HCC recurrence and liver graft complication rates were investigated. A total of 155 LTRs, having experienced post-transplant HCC recurrence, exhibited low survival probability at 1-, 3-, 5-, and 10-year observations. Our results demonstrated increased HCC recurrence rate after liver transplantation (p = 0.0316) following MMF administration; however, no significant increase was demonstrated following cyclosporine, tacrolimus, or sirolimus administration. Notably, our data demonstrated significantly increased HCC recurrence rate following MMF administration with cDDD > 0.4893 compared with cDDD ≤ 0.4893 or no administration of MMF (p < 0.0001). MMF administration significantly increases the risk of HCC recurrence. Moreover, a MMF-minimizing strategy (cDDD ≤ 0.4893) is recommended for recurrence-free survival.