Longterm calcineurin inhibitor therapy and brain function in patients after liver transplantation

How calcineurin inhibitors affect cognition

AIMS

With a focus on the discrepancy between preclinical and clinical findings, this review will gather comprehensive information about the effects of calcineurin inhibitors (CNI) on cognitive function and related brain pathology from in vitro, in vivo, and clinical studies. We also summarize the potential mechanisms that underlie the pathways related to CNI-induced cognitive impairment.

METHODS

We systematically searched articles in PubMed using keywords 'calcineurin inhibitor*' and 'cognition' to identify related articles, which the final list pertaining to underlying mechanisms of CNI on cognition.

RESULTS

Several studies have reported an association between calcineurin and the neuropathology of Alzheimer's disease (AD). AD is the most common neurocognitive disorder associated with amyloid plaques and neurofibrillary tangles in the brain, leading to cognitive impairment. CNI, including tacrolimus and cyclosporin A, are commonly prescribed for patients with transplantation of solid organs such as kidney, liver, or heart, those drugs are currently being used as long-term immunosuppressive therapy. Although preclinical models emphasize the favorable effects of CNI on the restoration of brain pathology due to the impacts of calcineurin on the alleviation of amyloid-beta deposition and tau hyperphosphorylation, or rescuing synaptic and mitochondrial functions, treatment-related neurotoxicity, resulting in cognitive dysfunctions has been observed in clinical settings of patients who received CNI.

CONCLUSION

Inconsistent results of CNI on cognition from clinical studies have been observed due to impairment of the blood-brain barrier, neuroinflammation mediated by reactive oxygen species, and alteration in mitochondrial fission, and extended research is required to confirm its promising use in cognitive impairment.

Management of long-term complications from immunosuppression

This review discusses long-term complications from immunosuppressants after liver transplantation and the management of these complications. Common complications of calcineurin inhibitors include nephrotoxicity and metabolic diseases. Nephrotoxicity can be managed by targeting a lower drug level and/or adding an immunosuppressant of a different class. Metabolic disorders can be managed by treating the underlying condition and targeting a lower drug level. Gastrointestinal adverse effects and myelosuppression are common complications of antimetabolites that are initially managed with dose reduction or discontinuation if adverse events persist. Mammalian targets of rapamycin inhibitors are associated with myelosuppression, proteinuria, impaired wound healing, and stomatitis, which may require dose reduction or discontinuation. Induction agents and agents used for steroid-refractory rejection or antibody-mediated rejection are reviewed. Other rare complications of immunosuppressants are discussed as well.

Mitochondrial Permeability Transition, Cell Death and Neurodegeneration

Neurodegenerative diseases are chronic conditions occurring when neurons die in specific brain regions that lead to loss of movement or cognitive functions. Despite the progress in understanding the mechanisms of this pathology, currently no cure exists to treat these types of diseases: for some of them the only help is alleviating the associated symptoms. Mitochondrial dysfunction has been shown to be involved in the pathogenesis of most the neurodegenerative disorders. The fast and transient permeability of mitochondria (the mitochondrial permeability transition, mPT) has been shown to be an initial step in the mechanism of apoptotic and necrotic cell death, which acts as a regulator of tissue regeneration for postmitotic neurons as it leads to the irreparable loss of cells and cell function. In this study, we review the role of the mitochondrial permeability transition in neuronal death in major neurodegenerative diseases, covering the inductors of mPTP opening in neurons, including the major ones-free radicals and calcium-and we discuss perspectives and difficulties in the development of a neuroprotective strategy based on the inhibition of mPTP in neurodegenerative disorders.

Prevalence of cognitive impairment in liver transplant recipients

Liver transplant (LT) recipients have a high burden of cognitive impairment risk factors identified in other populations, yet little work has explored cognition in the United States LT population. We characterized prevalence of cognitive impairment (CI) in LT recipients pre-LT and ≥3 months post-LT. Adult LT recipients with cirrhosis but without active pre-LT hepatic encephalopathy (HE) were screened for CI using the Montreal Cognitive Assessment (MoCA) for CI (MoCA <24) both pre-LT and ≥3 months post-LT. The association between cognitive performance and recipient characteristics was assessed using logistic regression. Of 107 LT recipients, 36% had pre-LT CI and 27% had post-LT CI [median (Q1-Q3) MoCA 26 (23-28)]. Each 1-point increase in pre-LT MoCA was associated with 26% lower odds of post-LT cognitive impairment (aOR .74, 95% CI .63-.87, p < .001), after adjusting for recipient age, history of HE, and time since LT. In this study of cirrhosis recipients without active pre-LT HE, cognitive impairment was prevalent before LT and remained prevalent ≥3 months after LT (27%), long after effects of portal hypertension on cognition would be expected to have resolved. Our data expose an urgent need for more comprehensive neurologic examination of LT recipients to better identify, characterize, and address predictors of post-LT cognitive impairment.

Development of a predictive nomogram for switching immunosuppressive drugs in pediatric liver transplant recipients

Background

Tacrolimus (TAC) is the preferred calcineurin inhibitor (CNI) for pediatric liver transplant recipients. However, some recipients may not achieve the desired therapeutic window concentration of TAC, leading to poor prognosis. This study aimed to develop a clinical model that can predict the effectiveness of TAC in pediatric liver transplant recipients and help clinicians quickly identify cyclosporin as an alternative.

Methods

We retrospectively analyzed data from 2,032 pediatric liver transplant recipients who underwent surgery at Renji Hospital, Shanghai Jiaotong University School of Medicine between 2006 and 2019. Demographic, comorbidity and pre-operative laboratory data were collected, and a nomogram was constructed using multivariate logistic regression analysis to estimate the risk of poor therapeutic outcomes for TAC-based immunosuppression.

Results

The constructed nomogram included seven parameters, namely recipient CYP3A4 genotype, pre-transplant cholangitis, GRWR, spleen long diameter, serum albumin, graft volume reduction, and donor CYP genotype. The nomogram showed good discriminative ability with an area under the receiver operating characteristic curve (AUC) of 74.5% and good calibration. Decision curve analysis indicated a high potential clinical application of the model.

Conclusion

This simple clinical model effectively predicts the risk of poor therapeutic outcomes in pediatric liver transplant recipients who receive TAC-based immunosuppression. Clinicians can use the model to identify cyclosporin as an alternative quickly, potentially improving patient prognosis.

Cognitive function, self-management, and outcomes among liver transplant recipients: LivCog, a multicenter, prospective study

Liver transplantation is a life-saving option for decompensated cirrhosis. Liver transplant recipients require advanced self-management skills, intact cognitive skills, and care partner support to improve long-term outcomes. Gaps remain in understanding post-liver transplant cognitive and health trajectories, and patient factors such as self-management skills, care partner support, and sleep. Our aims are to (1) assess pre-liver transplant to post-liver transplant cognitive trajectories and identify risk factors for persistent cognitive impairment; (2) evaluate associations between cognitive function and self-management skills, health behaviors, functional health status, and post-transplant outcomes; and (3) investigate potential mediators and moderators of associations between cognitive function and post-liver transplant outcomes. LivCog is a longitudinal, prospective observational study that will enroll 450 adult liver transplant recipients and their caregivers/care partners. The duration of the study is 5 years with 24 additional months of patient follow-up. Data will be collected from participants at 1, 3, 12, and 24 months post-transplant. Limited pre-liver transplant data will also be collected from waitlisted candidates. Data collection methods include interviews, surveys, cognitive assessments, and actigraphy/sleep diary measures. Patient measurements include sociodemographic characteristics, pretransplant health status, cognitive function, physical function, perioperative measures, medical history, transplant history, self-management skills, patient-reported outcomes, health behaviors, and clinical outcomes. Caregiver measures assess sociodemographic variables, health literacy, health care navigation skills, self-efficacy, care partner preparedness, nature and intensity of care, care partner burden, and community participation. By elucidating various health trajectories from pre-liver transplant to 2 years post-liver transplant, LivCog will be able to better characterize recipients at higher risk of cognitive impairment and compromised self-management. Findings will inform interventions targeting health behaviors, self-management, and caregiver supports to optimize outcomes.

Screening of cognitive performance in kidney transplant recipients: a mini review

Why should we screen?

The prevalence of cognitive impairment in kidney transplant recipients (KTRs) is up to 58%. The 10-year graft loss and mortality rates are above 30% and 50%, respectively, and executive malfunctioning increases disadvantageous outcomes.

What causes cognitive impairment in KTRs?

Strong risk factors are older age and chronic kidney disease. However, causes are multifactorial and include cardiovascular, cerebrovascular, neurodegenerative, inflammatory, uremic, psychiatric, and lifestyle-related susceptibilities.

How should we screen?

KTR-specific validated instruments or strategies do not exist. The central element should be a multidomain cognitive screening test that is sensitive to mild cognitive impairment, corrects for age and education, and includes executive functions testing. Cognitive trajectories, effects on everyday life and psychiatric comorbidities should be assessed by integrating the perspectives of both patients and knowledgeable informants.

When should we screen?

Screening should not be postponed if there is suspicion of impaired cognition. Different time points after transplantation tend to have their own characteristics.

Who should conduct the screening?

Screening should not be limited to specialists. It can be carried out by any healthcare professional who has received a limited amount of training.

What are the benefits of screening?

Screening does not provide a diagnosis. However, suggestive results change care in multiple ways. Goals are: Initiation of professional dementia work-up, securing of adherence, anticipation of potential complications (delirium, falls, frailty, functional impairment, malnutrition, etc.), mitigation of behavioral disorders, adjustment of diagnostic and therapeutic "load", reduction of caregiver burden and meeting of changing needs. We summarize data on the prevalence, risk factors and sequelae of cognitive impairment in KTRs. We also discuss the requirements for appropriate screening strategies and provide guiding principles regarding appropriate and safe care.

Gut microbiome-brain-cirrhosis axis

Cirrhosis is characterized by inflammation, degeneration, and fibrosis of liver tissue. Along with being the most common cause of liver failure and liver transplant, cirrhosis is a significant risk factor for several neuropsychiatric conditions. The most common of these is HE, which is characterized by cognitive and ataxic symptoms, resulting from the buildup of metabolic toxins with liver failure. However, cirrhosis patients also show a significantly increased risk for neurodegenerative diseases such as Alzheimer and Parkinson diseases, and for mood disorders such as anxiety and depression. In recent years, more attention has been played to communication between the ways the gut and liver communicate with each other and with the central nervous system, and the way these organs influence each other's function. This bidirectional communication has come to be known as the gut-liver-brain axis. The gut microbiome has emerged as a key mechanism affecting gut-liver, gut-brain, and brain-liver communication. Clinical studies and animal models have demonstrated the significant patterns of gut dysbiosis when cirrhosis is present, both with or without concomitant alcohol use disorder, and have provided compelling evidence that this dysbiosis also influences the cognitive and mood-related behaviors. In this review, we have summarized the pathophysiological and cognitive effects associated with cirrhosis, links to cirrhosis-associated disruption of the gut microbiome, and the current evidence from clinical and preclinical studies for the modulation of the gut microbiome as a treatment for cirrhosis and associated neuropsychiatric conditions.

Subjective Cognition Reported by Caregivers Is Correlated With Objective Cognition in Liver Transplant Recipients

Objective cognitive assessments, a gold standard diagnostic tool for cognitive impairment, may not be feasible in busy liver transplantation (LT) practice because they are often time consuming. This study determined whether subjective cognition, patients' self-ratings and/or caregivers' ratings of patients' cognition, reflects objective cognition in LT recipients. A convenience sample of 60 adult LT recipients and their caregivers, recruited at a single transplant center, participated in this cross-sectional descriptive study. Subjective cognition (ie, recipient self-rated and caregiver rated) was measured using the Everyday Cognition (ECog; global and 6 domain scores). Objective global and domain-specific cognition of recipients was measured using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Trail Making Test parts A and B, Digit Span Backward, and Rey-Osterrieth Complex Figure. Agreement between LT recipients' ECog scores and those of their caregivers was fair to moderate (intraclass correlation coefficient = 0.48 for global score, 0.35-0.56 for domain scores). Significant, albeit rather weak, correlations were found between subjective and objective scores. Recipients' ECog visuospatial abilities scores were correlated with Rey-Osterrieth Complex Figure scores (r_s  = -0.39; P = 0.007), whereas caregivers' ECog global, attention, visuospatial abilities, and organization scores were, respectively, correlated with the scores of RBANS global (r_s  = -0.33; P = 0.04) and attention (r_s  = -0.46; P = 0.005), Rey-Osterrieth Complex Figure (Copy; r_s  = -0.34; P = 0.03), and Trail Making Test part A (r_s  = 0.31; P = 0.049). The findings suggest that caregivers may estimate LT recipients' cognition better than recipients themselves. Caregivers may provide supplemental information that could be useful for clinicians when considering the cognitive functioning of LT recipients.

Redefining Success After Liver Transplantation: From Mortality Toward Function and Fulfillment

Liver transplantation (LT), the only cure for end-stage liver disease, is a lifesaving, costly, and limited resource. LT recipients (LTRs) are aging with an increasing burden of medical comorbidities. Patient and graft survival rates exceed 70% at 5 years; however, patient-centered health outcomes beyond survival have received relatively little attention. LTRs must have strong self-management skills to navigate health systems, adhere to clinical monitoring, and take complex, multidrug regimens. All of these tasks require formidable cognitive abilities for active learning and problem solving. Yet, LTRs are at higher risk for impaired cognition as a result of the high prevalence of pretransplant hepatic encephalopathy, multiple chronic conditions, alcohol use, physical frailty, sarcopenia, and older age. Cognitive impairment after transplant may persist and has been causally linked to poor self-management skills, worse physical function, and inferior health outcomes in other health care settings, yet its impact after LT is largely unknown. There is a need to study potentially modifiable, posttransplant targets including caregiver support, physical activity, sleep, and treatment adherence to inform future health system responses to promote the long-term health and well-being of LTRs. Prospective, longitudinal data collection that encompasses key sociodemographic, cognitive-behavioral, psychosocial, and medical factors is needed to improve risk prediction and better inform patient and caregiver expectations. Interventions with proactive monitoring, reducing medical complexity, and improved care coordination can be tailored to optimize posttransplant care. We propose a research agenda focused on understudied, potentially modifiable risk factors to improve the long-term health of LTRs. Our conceptual model accounts for cognitive function, caregiver and patient self-management skills, health behaviors, and patient-centered outcomes beyond mortality. We propose actionable health-system, patient, and caregiver-directed interventions to fill knowledge gaps and improve outcomes.

Reduced microglia activity in patients with long-term immunosuppressive therapy after liver transplantation

PURPOSE

Calcineurin inhibitors (CNI) can cause long-term impairment of brain function. Possible pathomechanisms include alterations of the cerebral immune system. This study used positron emission tomography (PET) imaging with the translocator protein (TSPO) ligand 18F-GE-180 to evaluate microglial activation in liver-transplanted patients under different regimens of immunosuppression.

METHODS

PET was performed in 22 liver-transplanted patients (3 CNI free, 9 with low-dose CNI, 10 with standard-dose CNI immunosuppression) and 9 healthy controls. The total distribution volume (VT) estimated in 12 volumes-of-interest was analyzed regarding TSPO genotype, CNI therapy, and cognitive performance.

RESULTS

In controls, VT was about 80% higher in high affinity binders (n = 5) compared to mixed affinity binders (n = 3). Mean VT corrected for TSPO genotype was significantly lower in patients compared to controls, especially in patients in whom CNI dose had been reduced because of nephrotoxic side effect.

CONCLUSION

Our results provide evidence of chronic suppression of microglial activity in liver-transplanted patients under CNI therapy especially in patients with high sensitivity to CNI toxicity.

[Importance of cognitive disorders in internal medicine: Pathophysiology, diagnosis, management. The example of systemic lupus erythematosus]

Systemic diseases, which are in France mainly monitored in internal medicine, affect multiple organs or tissues. While cutaneous or articular manifestations are the most common, neurological involvement is often associated with severity. Diagnosis of peripheral (e.g, neuropathies) or central (e.g, myelitis) nervous disorders is quite easy through clinical examination and dedicated complementary tests. However, neuropsychological manifestations that affect cognition, including memory, attention, executive functions or reasoning, are difficult to diagnose, sometimes trivialized by practitioners. Their causes are often numerous and interrelated. Nevertheless, these cognitive manifestations are closely related to patients' quality of life, affecting their social life, family dynamics and professional integration but also the treatment adherence. The purpose of this review, focused on the example of systemic lupus erythematosus, is to raise awareness of cognitive dysfunction in systemic diseases including their management from diagnosis to treatments. The final aim is to go further into setting up research groups and care programs for patients with cognitive impairment followed in internal medicine.

Impairment of Cognitive Function in Different Domains Early After Lung Transplantation

In this prospective observational pilot study patients with the diagnosis of end-stage lung disease and listed for lung transplantation underwent a cognitive function test battery before and after lung transplantation to investigate postoperative cognitive function in three domains (visual and verbal memory, executive functioning, concentration/speed of processing). Additionally we investigated intraoperative risk factors for postoperative cognitive dysfunction. In total, 24 patients were included in this pilot study. The incidence of postoperative cognitive dysfunction was 58.3%. In the cognitive dysfunction group, the domains executive functioning and concentration/attention were significantly impaired whereas memory was not affected. Patients with cognitive impairment had a significantly longer ICU stay. The strongest independent risk factor for the development of cognitive dysfunction was operation time. No influence of cerebral oxygen desaturations on cognitive dysfunction was found. This might have important implications for early psychological rehabilitation strategies in this high-risk patient collective.

Improvements in Disease-Specific Health-Related Quality of Life of Pediatric Liver Transplant Recipients During Immunosuppression Withdrawal

Long-term immunosuppression (IS) leads to systemic complications affecting health-related quality of life (HRQOL) in pediatric liver transplantation (LT) recipients. We serially assessed HRQOL using the PedsQL Generic and Multidimensional Fatigue Scales and Family Impact and Transplant Modules as part of a multicenter prospective immunosuppression withdrawal (ISW) trial between 2012 and 2018. Participants received a primary LT ≥4 years before the study and were on stable IS with normal liver tests and without rejection in the prior 2 years. IS was withdrawn in 7 steps over 36 to 48 weeks. HRQOL was assessed at regular intervals. The primary endpoint was change in disease-specific HRQOL measured by the PedsQL Transplant Module. Generic HRQOL was measured by the PedsQL Generic Scale and was compared with an age-matched and sex-matched multicenter cohort. Of the 88 participants, 39 were boys, median age was 11 years (range, 8-13), and time since transplant was 9 years (range, 6-11). For 36 months, disease-specific HRQOL improved for all participants, whereas generic HRQOL was unchanged. Neither generic nor disease-specific HRQOL changed for the 35 participants who developed acute rejection during ISW. In the first use of patient-reported outcome measures during an ISW trial, we found improvements in disease-specific HRQOL in all participants and no lasting detrimental effects in those who experienced rejection.

Neurologic Toxicities Associated with Tumor Necrosis Factor Inhibitors and Calcineurin Inhibitors

The calcineurin inhibitors cyclosporine and tacrolimus are used for their immunosuppressive effects. Neurotoxic side effects include tremor, paresthesia, and headache. Rarer neurotoxicities include seizure, posterior reversible encephalopathy syndrome, and encephalopathy. Tacrolimus tends to be more neurotoxic than cyclosporine. Management of toxicities associated with calcineurin inhibitors includes dose reduction, switching between calcineurin inhibitors, or switching to a calcineurin-free regimen. Tumor necrosis factor (TNF) inhibitors are used in autoimmune diseases. Management of demyelinating conditions among patients treated with anti-TNF should follow standard of care and withdrawal of the anti-TNF. This drug class should be avoided in patients with a history of demyelinating conditions.

Cognitive Function in Liver Transplant Recipients Who Survived More Than 6 Months

Introduction:

Current research in the areas of liver transplant and cognitive function has primarily examined cognitive changes from pre- to 1-year posttransplant, resulting in an insufficient understanding of cognitive trajectory beyond early periods of transplant and its impact on self-management. This study aimed (1) to describe global and domain-specific cognitive function in liver transplant recipients who survived more than 6 months after transplant and (2) to describe patient and clinical characteristics of recipients with impaired global and/or domain-specific cognitive function. Further, this study explored the potential relationships between cognitive function and self-management by examining differences in cognitive function by levels of self-management.

Design:

This secondary data analysis included 107 adult liver transplant recipients, who had a functioning transplant for at least 6 months. Data of cognitive function, demographic and clinical characteristics, and self-management were extracted for this study. T tests, Mann-Whitney tests, and Kruskal-Wallis tests were used to examine differences in cognitive function by variables.

Results:

More than half of the recipients had global cognitive impairment. Significant differences were found in global and domain-specific cognitive function. Older, male, married, or deceased donor recipients had lower cognitive test scores than younger, female, single, or living donor recipients. There were no significant differences in global and domain-specific cognitive function by time since transplant and levels of self-management.

Discussion:

Future longitudinal studies should examine the long-term trajectory of cognitive function posttransplant. Other factors such as caregivers’ participation in self-management should be accounted for in future studies when examining the relationship between cognitive function and self-management.

Tacrolimus-Associated Psychotic Disorder: A Report of 2 Cases

Psychotic disorders are a group of psychiatric disorders characterized by the presence of delusions, hallucinations, bizarre behavior, and disorganized speech. There are several possible causes for the occurrence of psychotic disorders in patients who underwent solid organ transplant, including pre-existing mental illness, electrolyte disturbances, infections of the central nervous system, and adverse reaction to drugs. Calcineurin inhibitors are a class of immunosuppressive drugs, such as tacrolimus and cyclosporine, that are currently considered the mainstay in the immunosuppressive drug regimen of patients who underwent solid organ transplant. Neurotoxicity is one of the adverse reactions associated with the use of calcineurin inhibitors, ranging from upper limb tremors to psychotic disorders and seizures. We report the cases of 2 liver transplant recipients who developed severe psychotic disorder 1 month after the procedure. After an extensive investigation for other possible triggers of psychiatric disease, the use of tacrolimus was considered to be the most likely cause for the acute psychotic disorder. In less than 24 hours after suspension of that drug, all symptoms disappeared in both patients, making a causal relationship with tacrolimus even more likely. The patients were then given cyclosporine, another drug from the same class, allowing for adequate immunosuppression and preserved graft function, with no further psychiatric symptoms. This report confirms that a 24-hour trial of tacrolimus suspension can be safe and effective in the diagnosis of drug-related psychotic disorders in patients who underwent liver transplant. This article is compliant with the Helsinki Congress and the Istanbul Declaration.

Spotlight on Impactful Research: Long-Term Calcineurin Inhibitor Therapy and Brain Function in Patients After Liver Transplantation

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Brain function and metabolism in patients with long-term tacrolimus therapy after kidney transplantation in comparison to patients after liver transplantation

Background

About 50% of the patients 5–7 years after kidney transplantation show impairment of memory, attention and executive function. Tacrolimus frequently induces neurological complications in the first few weeks after transplantation. Furthermore, tacrolimus treatment is associated with impaired cognitive function in the long-term in patients after liver transplantation. We hypothesize that long-term tacrolimus therapy is associated with cognitive dysfunction and alterations of brain structure and metabolism in patients after kidney transplantation.

Methods

Twenty-one patients 10 years after kidney transplantation underwent cognitive testing, magnetic resonance imaging and whole brain 31-phosphor magnetic resonance spectroscopy for the assessment of brain function, structure and energy metabolism. Using a cross-sectional study design the results were compared to those of patients 1 (n = 11) and 5 years (n = 10) after kidney transplantation, and healthy controls (n = 17). To further analyze the share of transplantation, tacrolimus therapy and kidney dysfunction on the results patients after liver transplantation (n = 9) were selected as a patient control group.

Results

Patients 1 and 10 years after kidney transplantation (p = 0.02) similar to patients 10 years after liver transplantation (p<0.01) showed significantly worse cognitive function than healthy controls. In contrast to patients after liver transplantation patients after kidney transplantation showed significantly reduced adenosine triphosphate levels in the brain compared to healthy controls (p≤0.01). Patients 1 and 5 years after kidney transplantation had significantly increased periventricular hyperintensities compared to healthy controls (p<0.05).

Conclusions

Our data indicate that cognitive impairment in the long-term after liver and kidney transplantation cannot exclusively be explained by CNI neurotoxicity.

Hepatic Encephalopathy Is Reversible in the Long Term After Liver Transplantation

Cognitive dysfunction caused by hepatic encephalopathy (HE) improves within the first year after liver transplantation (LT). However, cognitive restitution seems to be incomplete in a subset of patients and after LT a new-onset cognitive decline was described. Data about the longterm development of cognitive function after liver transplantation (LT) are sparse. This prospective study analyzed whether a history of hepatic encephalopathy (HE) before LT had an impact on the longterm outcome of cognitive function after LT and if patients who underwent LT 5 years earlier showed worse cognitive function than healthy controls. The cognitive function of 34 patients was assessed before LT and at 1 year and 5 years after LT by psychometric tests, including the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the portosystemic encephalopathy syndrome test, which provides the psychometric hepatic encephalopathy score (PHES). Furthermore, patients completed surveys to assess health-related quality of life (HRQOL). An 22 additional patients were included after LT. Patients were subdivided by having a history of HE before LT. The control group consisted of 55 healthy patients adjusted for age and education. Before LT, patients performed significantly worse than controls in the psychometric tests: RBANS Total Scale (TS), mean ± standard deviation (SD), 92.6 ± 13.3 versus 99.9 ± 12.0, P = 0.01; and PHES, median (interquartile range [IQR]), 0 (-3 to 1) versus 1 (0-2), P < 0.001. At 1 year after LT, patients with a history of HE still showed cognitive impairment compared with controls: RBANS TS, mean ± SD, 89.8 ± 15.1 versus 99.9 ± 12.0, P < 0.01; and PHES, median (IQR), 0 (-2 to 1.25) versus 1 (0-2), P = 0.03. At 5 years after LT, patients with and without a history of HE showed normal cognitive function and improved HRQOL. In conclusion, HE-associated cognitive impairment seems to be reversible within 5 years after LT.

Impact of immunosuppressive therapy on brain derived cytokines after liver transplantation

BACKGROUND

While acute neurotoxic side effects of calcineurin inhibitors (CNI) are well-known, data upon long-term effects on brain structure and function are sparse. We hypothesize that long-term CNI therapy affects the neuroimmune system, thereby, increasing the risk of neurodegeneration. Here, we measured the impact of CNI therapy on plasma levels of brain- and T cell-derived cytokines in a cohort of patients after liver transplantation (LT).

METHODS

Levels of T cell-mediated cytokines (e.g. Interferon-γ (IFN-γ)) and brain-derived cytokines (e.g. brain derived neurotrophic factor (BDNF), platelet derived growth factor (PDGF)) were measured by multiplex assays in plasma of 82 patients about 10 years after LT (17 with CNI free, 35 with CNI low dose, 30 with standard dose CNI immunosuppression) and 33 healthy controls. Data were related to psychometric test results and parameters of cerebral magnetic resonance imaging.

RESULTS

IFN-γ levels were significantly higher in the CNI free LT patient group (p=0.027) compared to healthy controls. BDNF levels were significantly lower in LT patients treated with CNI (CNI low: p<0.001; CNI standard: p=0.016) compared to controls. PDGF levels were significantly lower in the CNI low dose group (p=0.004) and for PDGF-AB/BB also in the CNI standard dose group (p=0.029) compared to controls. BDNF and PDGF negatively correlated with cognitive function and brain volume (p<0.05) in the CNI low dose group.

CONCLUSION

Our results imply that long-term treatment with CNI suppresses BDNF and PDGF expression, both crucial for neuronal signaling, cell survival and synaptic plasticity and thereby may lead to cognitive dysfunction and neurodegeneration.

Quantitative magnetic resonance imaging indicates brain tissue alterations in patients after liver transplantation

PURPOSE

To investigate cerebral microstructural alterations in patients treated with calcineurin inhibitors (CNI) after orthotopic liver transplantation (OLT) using quantitative magnetic resonance imaging (qMRI) and a cross-sectional study design.

METHODS

Cerebral qMRI was performed in 85 patients in a median 10 years after OLT compared to 31 healthy controls. Patients were treated with different dosages of CNI or with a CNI-free immunosuppression (CNI-free: n = 19; CNI-low: n = 36; CNI-standard: n = 30). T2-, T2*- and T2'- relaxation times, as well as apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in brain gray and white matter by using the regions of interest method.

RESULTS

In comparison to controls, patients revealed significantly increased T2, T2*, T2', ADC and reduced FA, predominantly in the frontal white matter, indicating microstructural brain alterations represented by increased free water (increased T2), reduced neuronal metabolism (increased T2') and a lower degree of spatial organization of the nervous fibers (reduced FA). CNI-low and CNI-free patients showed more alterations than CNI-standard patients. Analysis of their history revealed impairment of kidney function while under standard CNI dose suggesting that these patients may be more vulnerable to toxic CNI side-effects.

CONCLUSION

Our findings suggest that the individual sensitivity to toxic side effects should be considered when choosing an appropriate immunosuppressive regimen in patients after liver transplantation.

Cerebral metabolite alterations in patients with posttransplant encephalopathy after liver transplantation

Background

In the first weeks after liver transplantation about 30% of the patients develop a posttransplant encephalopathy. A posttransplant encephalopathy comprises metabolic-toxic caused symptoms such as disorientation, confusion, hallucinations, cognitive dysfunction and seizures. We hypothesize that alterations of cerebral metabolites before liver transplantation predispose posttransplant encephalopathy development after liver transplantation.

Methods

31 patients with chronic liver disease underwent magnetic resonance spectroscopy (MRS) before liver transplantation to assess glutamine/glutamate (Glx), myo-Inositol (mI), choline (Cho), creatine/phosphocreatine- and N-acetyl-aspartate/N-acetyl-aspartate-glutamate concentrations in the thalamus, lentiform nucleus and white matter. Of these, 14 patients underwent MRS additionally after liver transplantation. Furthermore, 15 patients received MRS only after liver transplantation. Patients’ data were compared to 20 healthy age adjusted controls.

Results

Patients showed significantly increased Glx and decreased mI and Cho concentrations compared to controls before liver transplantation (p≤0.01). The MRS values before liver transplantation of patients with posttransplant encephalopathy showed no significant difference compared to patients without posttransplant encephalopathy. Patients after liver transplantation showed increased Glx concentrations (p≤0.01) compared to controls, however, patients with and without posttransplant encephalopathy did not differ. Patients with posttransplant encephalopathy who underwent MRS before and after liver transplantation showed a significant mI increase in all three brain regions (p<0.04) and Glx decrease in the lentiform nucleus after liver transplantation (p = 0.04) while patients without posttransplant encephalopathy only showed a mI increase in the thalamus (p = 0.04).

Conclusion

Patients with and without posttransplant encephalopathy showed no significant difference in cerebral metabolites before liver transplantation. However, the paired sub-analysis indicates that the extent of cerebral metabolite alterations in patients with liver cirrhosis might be critical for the development of posttransplant encephalopathy after liver transplantation.

Brain metabolic alterations in patients with long-term calcineurin inhibitor therapy after liver transplantation

BACKGROUND

Calcineurin inhibitor (CNI) neurotoxicity after liver transplantation might be due to impairment of the cerebral metabolism.

AIMS

To investigate CNI-related alterations of brain metabolite distributions and associations between cognitive function and brain metabolism in patients with long-term CNI treatment after liver transplantation.

METHODS

Eighty-two patients (19 CNI free, 34 CNI low-dose and 29 standard-dose CNI immunosuppression) 10 years after liver transplantation and 32 adjusted healthy controls underwent nonlocalised brain phosphorus magnetic resonance spectroscopy (MRS) and single voxel proton MRS in the parietal white matter to estimate brain metabolite contents. The MRS results were correlated with psychometric data assessing cognitive function.

RESULTS

Phosphorus metabolite concentrations with the exception of phosphocreatine (PCr) were reduced in patients compared to controls. Particularly, patients with low-dose CNI therapy showed a significant decrease in adenosine triphosphate (0.209 ± 0.012 vs 0.222 ± 0.010; P < 0.001) and a significant increase in PCr (0.344 ± 0.026 vs 0.321 ± 0.017; P < 0.001) compared to controls. Myo-Inositol in the CNI free group (2.719 ± 0.549 institutional unit [iu]) was significantly lower compared to controls (3.181 ± 0.425 iu; P = 0.02), patients on low-dose (3.130 ± 0.513 iu; P < 0.05) and standard-dose CNI therapy (3.207 ± 0.632 iu; P < 0.02). Glutamate and glutamine levels correlated negatively with cognitive function (Repeatable Battery for the Assessment of Neuropsychological Status Total Scale: R = -0.362, P = 0.029).

CONCLUSION

Long-term CNI therapy after liver transplantation might be associated with alterations of brain metabolites.

Impact of Immunosuppression on Executive Functioning After Pediatric Liver Transplantation: An Observational Cohort Study

OBJECTIVES

Children after liver transplantation show increased rates of impaired cognitive functioning. We aimed to assess the potential effects of immunosuppressive therapy on executive functioning measured by the Children's Color Trail Test and the cognitive functioning module of the PedsQL (cogPedsQL) in liver transplanted children to explore potential targets for intervention to improve executive functioning.

METHODS

We performed a cross-sectional study in 155 children (78 girls) aged 10.4 (2-18) years at 5.0 (0.1-17) years after liver transplantation, with follow-up at 6 months in n = 114. Executive functioning was assessed by Children's Color Trail Test (ages 8-16) and by patients and parent-proxy cogPedsQL (ages 5-18/2-18, respectively). Results were correlated with clinical parameters. Stability of results over time was compared between n = 23 patients who for clinical reasons switched from twice daily calcineurin inhibitor (CNI) to once-daily slow-release tacrolimus (Tac) during the study period, and patients with unchanged CNI.

RESULTS

Worse executive functioning was associated with longer stay in the intensive care unit and longer time elapsed since transplantation. No difference was found between users of cyclosporine and Tac. Children on once-daily slow-release Tac performed better than children on twice-daily Tac. In children who switched from twice-daily CNI to once-daily Tac, parent-proxy cogPedsQL improved significantly compared to stable results in the nonswitch group.

CONCLUSIONS

In addition to a strong impact of disease burden around transplantation, executive functioning appears to deteriorate over time. Although there is no clear-cut advantage of any CNI, once-daily Tac appears to be advantageous compared to twice-daily Tac.

Cognitive impairment after liver transplantation: residual hepatic encephalopathy or posttransplant encephalopathy?

Liver transplantation (LT) represents the definitive treatment for end-stage liver disease. Cognitive impairment following LT is frequent, referred to as postliver transplant encephalopathy (PLTE). LT removes the underlying chronic liver disease, and until recently hepatic encephalopathy (HE) was assumed to be fully reversible after LT. However, increasing evidence indicates that some degree of cognitive impairment may be present after LT. To which extent PLTE reflects cognitive impairment caused by residual HE (RHE) or the combined effect of other factors affecting brain function before, during, and after LT is not clarified. None of the available psychometric and neurophysiological tests used for detecting HE is shown to be able to distinguish between etiologies. The available, mostly retrospective, clinical studies indicate a high prevalence of abnormal psychometric tests after LT, and not all seem to recover completely. The patients with earlier HE show the most marked improvements, suggesting that the clinical picture of the early PLTE, in fact, represents RHE. Other early post-LT etiologies for PLTE comprise cerebral ischemia, critical illness encephalopathy, and immunosuppressive therapy. Late-onset etiologies comprise diabetes and hypertension, among others. PLTE regardless of etiology is a worrying issue and needs more attention in the form of mechanistic research, development of diagnostic/discriminative tools, and standardized prospective clinical studies.

A Friend or Foe: Calcineurin across the Gamut of Neurological Disorders

The serine/threonine phosphatase calcineurin (CaN) is a unique but confounding calcium/calmodulin-mediated enzyme. CaN has shown to play essential roles from regulating calcium homeostasis to being an intricate part of learning and memory formation. Neurological disorders, despite differing in their etiology, share similar pathological outcomes, such as mitochondrial dysfunction and apoptotic signaling brought about by excitotoxic elements. CaN, being deeply integrated in vital neuronal functions, may be implicated in various neurological disorders. Understanding the enzyme and its physiological niche in the nervous system is vital in uncovering its roles in the spectrum of brain disorders. By reviewing the crosstalk in different neurological pathologies, a possible grasp of CaN's complex signaling may lead to forming better neurotherapy. This Outlook attempts to explore the various neuronal functions of CaN and investigate its pervasive role through the gamut of neurological disorders.