Neurocognitive Function Changes Following Kidney Transplant: A Prospective Study

Rationale & Objective

Patients with advanced kidney disease are at risk for cognitive impairment, which may persist after kidney transplantation. We sought to understand changes in neurocognitive function domains utilizing comprehensive cognitive assessments.

Study Design

Prospective cohort study.

Setting & Population

Single-center study of patients undergoing kidney transplantation.

Exposure

Kidney transplantation.

Outcomes

Changes in neurocognitive function as measured by the Repeatable Battery for Assessment of Neuropsychological Status (RBANS) and the Trail Making Test Parts A and B (TRAIL A and B) before transplantation (baseline) and compared to 3 months and 12 months posttransplant.

Analytical Approach

Wilcoxon signed-rank and linear mixed effect models were utilized to assess changes in neurocognitive scores at 3 months and 12 months compared to baseline.

Results

Thirty-two patients were included with a mean age of 45 years, 47% female, 85% White, and 62% with at least some college education. Hypertension and diabetes were etiologies of kidney disease in 31% and 25% of patients, respectively. Baseline RBANS and TRAIL A and B scores averaged 84.7 ± 14, 40.4 ± 9.9, and 41 ± 11.5, respectively. Although there were posttransplant improvements in immediate and delayed memory at 3 months, these were not sustained at 12 months. There were no significant differences from baseline at 3 months and 12 months in RBANS index scores for language, visuospatial/constructional abilities, and attention. Compared to baseline, TRAIL A scores were not significantly different at 3 months but were significantly improved at 12 months, whereas TRAIL B scores improved significantly at both 3 months and 12 months.

Limitations

Single-center design and small sample size.

Conclusions

Utilizing comprehensive cognitive assessments, we found improvements in attention and executive function in the first posttransplant year as measured by TRAIL A and B. However, there was no significant change in global cognition as measured by RBANS. These findings identify cognitive domains for potential intervention in the posttransplant population.

The contributions of eye gaze fixations and target-lure similarity to behavioral and fMRI indices of pattern separation and pattern completion

Pattern separation and pattern completion are generally studied in humans using mnemonic discrimination tasks such as the Mnemonic Similarity Task (MST) where participants identify similar lures and repeated items from a series of images. Failures to correctly discriminate lures are thought to reflect a failure of pattern separation and a propensity toward pattern completion. Recent research has challenged this perspective, suggesting that poor encoding rather than pattern completion accounts for the occurrence of false alarm responses to similar lures. In two experiments, participants completed a continuous recognition task version of the MST while eye movement (Experiments 1 and 2) and fMRI data (Experiment 2) were collected. In Experiment 1, we replicated the result that fixation counts at study predicted accuracy on lure trials (consistent with poor encoding predicting mnemonic discrimination performance), but this effect was not observed in our fMRI task. In both experiments, we found that target-lure similarity was a strong predictor of accuracy on lure trials. Further, we found that fMRI activation changes in the hippocampus were significantly correlated with the number of fixations at study for correct but not incorrect mnemonic discrimination judgments when controlling for target-lure similarity. Our findings indicate that while eye movements during encoding predict subsequent hippocampal activation changes for correct mnemonic discriminations, the predictive power of eye movements for activation changes for incorrect mnemonic discrimination trials was modest at best.

Sleep Fragmentation and Cognitive Trajectories After Critical Illness

BACKGROUND

ICU survivors can experience both cognitive dysfunction and persistent sleep disturbances after hospitalization. Sleep disturbances have been linked with cognitive impairment in various patient populations, and the apolipoprotein E (APOE) genotype has been linked to sleep-related impairments in cognition.

RESEARCH QUESTION

Is there an association between sleep, long-term cognition, and APOE status in ICU survivors?

STUDY DESIGN AND METHODS

We enrolled 150 patients from five centers who had been mechanically ventilated for at least 3 days; 102 patients survived to ICU discharge. Actigraphy and cognitive testing were undertaken at 7 days, 6 months, and 12 months after ICU discharge, and sleep duration, quality, and timing were estimated by actigraphy. APOE single nucleotide polymorphisms were assessed for each patient.

RESULTS

Actigraphy-estimated sleep fragmentation, but not total sleep time or interdaily stability (estimate of circadian rhythmicity), was associated with worse cognitive impairment at 7 days of ICU discharge. No actigraphy-estimated variable of sleep estimation at 7 days post-ICU discharge predicted cognitive impairment or persistent sleep abnormalities at 6 and 12 months of follow-up in subsequently assessed survivors. Possessing the APOE ε4 allele was not significantly associated with sleep disturbances and its presence did not modify the risk of sleep-related cognitive impairment at follow-up.

INTERPRETATION

Sleep fragmentation estimated by actigraphy was associated with worse cognitive performance in hospital, but not at later time intervals. Further research is needed to better delineate the relationship between persistent sleep disturbances and cognition in larger numbers of ICU survivors.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02086877; URL: www.clinicaltrials.gov.

Cognitive effects of androgen receptor (AR) directed therapies for advanced cancer of the prostate (COGCaP)

TPS5098

Background: Androgen deprivation therapy (ADT) is the cornerstone of treatment for prostate cancer (CaP). However, the relationship between ADT and the development of cognitive dysfunction in men with CaP is controversial. Past studies had various methodological limitations, including the inconsistency and insensitivity of measures used for cognitive testing. Methods: COGCaP is a multi-site, prospective observational study of cognitive function and patient reported outcomes in men with CaP treated with ADT and androgen receptor (AR) directed therapies such as enzalutamide or abiraterone acetate (AA) conducted across four U.S. sites. Patients with metastatic castration-resistant or hormone sensitive CaP starting abiraterone (N=50), or non-metastatic or metastatic castration-resistant CaP starting enzalutamide (N=50) undergo cognitive and patient reported outcome assessments at baseline, 3, 6, and 12 months. The primary endpoint compares mean change in cognitive function between groups at 3 months using CANTAB, a computer-based measure of cognitive function. This design achieves a power of 80% to detect a between-group difference in mean cognitive composite score of < 1 standard deviation and a two-sided type I error rate of 0.05. Functional MRI (fMRI) images will be assessed between baseline and 3 months to assess structural and functional changes in the brain as secondary endpoints. Study patients will be incorporated into a model of genetic risk of cognitive dysfunction in order to identify populations that are especially vulnerable to cognitive change when undergoing androgen deprivation. This ongoing study will define a reproducible methodology for cognitive assessments via computer based tests that can be standardized and disseminated within multi-site trials of men with CaP. Clinical trial information: NCT03016741.

Niacin treatment of the atherogenic lipid profile and Lp(a) in diabetes

OBJECTIVE

We tested the hypotheses that niacin is effective for the separate treatments of abnormalities of LDL particle size, HDL2 percentage and Lp(a) without potential negative effects on glycated haemoglobin.

RESEARCH DESIGN AND METHODS

The atherogenic lipid profile lipids, such as triglycerides, small, dense LDL cholesterol (LDLc) particle mass, LDL particle size, total HDLc and HDL2 percentage as well as Lp(a), were measured in 42 diabetic patients with abnormalities of LDL particle size, HDL2 percentage and/or Lp(a) levels before and after niacin treatment. LDL particle size and HDL2 were measured using polyacrylamide gradient gel electrophoreses and Lp(a) was measured by enzyme-linked immunoabsorbance assay (ELISA).

RESULTS

After niacin treatment, LDL peak particle diameter increased from 252 +/- 7 A to 263 +/- 7 (p < 0.0001), small, dense LDLc particle mass decreased from 27 +/- 11 mg/dL to 15 +/- 4 (p < 0.0001), total HDLc increased from 39 +/- 7 mg/dL to 51 +/- 11 (p < 0.0001), HDL2 as the percentage of total HDLc mass increased from 29 +/- 8% to 45 +/- 10 (p < 0.0001) and Lp(a) decreased from 43 +/- 17 mg/dL to 25 +/- 10 (p < 0.0001). Mean haemoglobin A1c level was improved during treatment from 7.6 +/- 1.8% to 6.5 +/- 1.0 (p < 0.0001) using increased oral agent and insulin treatment doses in more than 90% of the patients. A total of 21% of the patients were unable to tolerate niacin owing to reversible side-effects, and 14% were unable to adhere to the niacin dosing regimen of three times daily.

CONCLUSIONS

These data indicate that in diabetic patients, niacin (i) is effective for treating diabetic dyslipidaemias associated with both the atherogenic lipid profile and Lp(a); (ii) must be used with modern and aggressive oral hypoglycaemic agents or insulin treatment; and (iii) is an important drug to treat diabetes dyslipidaemias because of its broad spectrum of effectiveness.

Inhibition of mammary tumorigenesis in carcinogen-treated Lewis rats by suppression of prolactin secretion

One hundred sixty-eight female Lewis rats were treated intragastrically with 10 mg 7,12-dimethylbenz[a]anthracene at 56 and 63 days of age. Pituitary prolactin secretion was suppressed in one-half of these rats by daily sc administrations of 2-bromoergocryptine mesylate (CB-154; 0.4 mg/100 g body wt) from 29 to 90 days of age (series 1) and from 90 to 140 days of age (series 2). Treatment with CB-154 was initiated prior to the onset of palpable mammary carcinomas. Control rats were given injections of saline. Inguinal mammary glands were excised from 10 control and 10 CB-154-treated rats at the cessation of saline and CB-154 treatments and examined for hyperplastic nodules (HN). The remaining rats were palpated weekly for mammary carcinomas (MC) and killed at 200 days of age. Mean number of HN per rat, mean number of MC per rat, and percent of rats with MC were, respectively: series 1--controls, 0.6, 1.5, and 68; CB-154 treatment, 0.5, 1.1, and 62; series 2--controls, 10.4, 2.0, and 94; CB-154 treatment, 5.1, 1.1, and 56. The number of HN and MC was only slightly reduced in rats when prolactin was suppressed during carcinogen treatment (series 1) but markedly reduced when prolactin was suppressed after carcinogen treatment (series 2). These results provide evidence that prolactin is involved in the early development of mammary dysplasias in the carcinogen-treated female Lewis rat.