An Approach to Neurological Disorders in a Kidney Transplant Recipient

Predictors of academic delay post-pediatric kidney transplant in the USA

BACKGROUND

Pediatric patients with kidney failure often experience cognitive delays. However, academic delay (being more than one grade level below age-appropriate grade, or in special education) after pediatric kidney transplantation (KTx) has not been explored. We sought to identify patient characteristics associated with a higher risk of academic delay 1 year post-KTx.

METHODS

We used the United Network for Organ Sharing (UNOS) database to identify children aged 6-17 years who received a primary KTx between 2014 and 2021 and had a functioning graft 1 year after KTx. The primary outcome was the patient's academic progress at 1 year post-transplant. The secondary outcome was change in academic progress between transplant and 1-year follow-up: onset of new delay, resolution of pre-existing delay, persistence of delay, or no delay at either timepoint. Binomial and multinomial mixed effects logistic regression models were used to predict each outcome based on patient characteristics.

RESULTS

The study included 2197 patients, of whom 14% demonstrated academic delay at 1 year post-KTx, 4% demonstrated a new onset of academic delay, 5% demonstrated a resolution of academic delay, and 10% demonstrated persistent academic delay. Patients undergoing transplantation at a younger age, receiving a deceased donor kidney, experiencing longer waitlist times, and undergoing KTx for vascular or other disease indications for KTx were more likely to experience academic delays, including new-onset academic delays.

CONCLUSIONS

Academic delays are frequently reported among pediatric KTx recipients. Additional academic support may help resolving or preventing academic delay for at-risk subgroups of children undergoing KTx.

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.

Conclusive demonstration of iatrogenic Alzheimer's disease transmission in a model of stem cell transplantation

The risk of iatrogenic disease is often underestimated as a concern in contemporary medical procedures, encompassing tissue and organ transplantation, stem cell therapies, blood transfusions, and the administration of blood-derived products. In this context, despite the prevailing belief that Alzheimer's disease (AD) manifests primarily in familial and sporadic forms, our investigation reveals an unexpected transplantable variant of AD in a preclinical context, potentially indicating iatrogenic transmission in AD patients. Through adoptive transplantation of donor bone marrow stem cells carrying a mutant human amyloid precursor protein (APP) transgene into either APP-deficient knockout or normal recipient animals, we observed rapid development of AD pathological hallmarks. These pathological features were significantly accelerated and emerged within 6-9 months post transplantation and included compromised blood-brain barrier integrity, heightened cerebral vascular neoangiogenesis, elevated brain-associated β-amyloid levels, and cognitive impairment. Furthermore, our findings underscore the contribution of β-amyloid burden originating outside of the central nervous system to AD pathogenesis within the brain. We conclude that stem cell transplantation from donors harboring a pathogenic mutant allele can effectively transfer central nervous system diseases to healthy recipients, mirroring the pathogenesis observed in the donor. Consequently, our observations advocate for genomic sequencing of donor specimens prior to tissue, organ, or stem cell transplantation therapies, as well as blood transfusions and blood-derived product administration, to mitigate the risk of iatrogenic diseases.

Drugs with a negative impact on cognitive functions (Part 2): drug classes to consider while prescribing in CKD patients

There is growing evidence that chronic kidney disease (CKD) is an independent risk factor for cognitive impairment, especially due to vascular damage, blood-brain barrier disruption and uremic toxins. Given the presence of multiple comorbidities, the medication regimen of CKD patients often becomes very complex. Several medications such as psychotropic agents, drugs with anticholinergic properties, GABAergic drugs, opioids, corticosteroids, antibiotics and others have been linked to negative effects on cognition. These drugs are frequently included in the treatment regimen of CKD patients. The first review of this series described how CKD could represent a risk factor for adverse drug reactions affecting the central nervous system. This second review will describe some of the most common medications associated with cognitive impairment (in the general population and in CKD) and describe their effects.

Current recommendations regarding evaluation of cognitive functioning in organ transplant candidates

PURPOSE OF REVIEW

Cognitive impairment is associated with negative effects on solid organ transplant candidates, recipients, and their care partners. However, because of the heterogeneity of mechanisms, presentations, and assessment measures, research suggests a wide array of impairments, patterns of impairments, and unclear trajectories posttransplant. This review provides an abbreviated synthesis of recent research on cognitive impairments observed in organ-eligible candidates and potential trajectories through posttransplant, current clinical recommendations regarding integration of assessment into routine clinical transplant practice, as well as recommendations for future research.

RECENT FINDINGS

Transplantation may resolve certain disease-contributing factors to cognitive impairments but also introduces new potential neurocognitive assaults. Recent studies in kidney and lung recipients document continued impairments in subsets of patients, particularly those identified as frail. For liver candidates, new assessment measures of hepatic encephalopathy have been developed and preliminarily tested with potential for translation into routine clinical care. Clinical implications, as well as ethical considerations are discussed.

SUMMARY

Although guidelines agree that cognitive assessment is an important part of the organ transplantation process, many questions remain of how to best assess cognition and intervene when cognitive impairment is identified in transplant populations. Further research should focus on prospective, longitudinal assessments in transplant-eligible populations through posttransplant.