Dementia and cognitive impairment in ESRD: diagnostic and therapeutic strategies. Kidney Int. 2011;79:14-22. [PMID: 20861818 DOI: 10.1038/ki.2010.336]

Neuropathy - Exponent of Accelerated Involution in Uremia: The Role of Carbamylation

Premature loss of functional integrity of the nervous system in chronic renal failure (CRF) as a consequence of persistent biological activities of the general uremic milieu is almost identical to its structural and functional involution during the process of physiological ageing, but disproportionate and independent of chronological age. In the hyperuremic status of CRF (urea - carbamide), forced carbamylation, as a non-enzymatic post-translational modification (NEPTM) of proteins and amino acids, by changing their biological properties and decreasing proteolysis capacity, represents pathogenetic potential of intensified molecular ageing and accelerated, pathological involution. Physiological predisposition and the exposure of neuropathy before complications of other organs and organ systems in CRF, due to the simultaneous and mutually pathogenetically related uremic lesion and the tissue and vascular segment of the nervous system, direct interest towards proteomic analytical techniques of quantification of carbamylated products as biomarkers of uremic neurotoxicity. Hypothetically, identical to the already established applications of other NEPTM products in practice, they have the potential of clinical methodology in the evaluation of uremic neuropathy and its contribution to the general prediction, but also to the change of the conventional CRF classification. In addition, the identification and therapeutic control of the substrate of accelerated involution, responsible for the amplification of not only neurological but also general degenerative processes in CRF, is attractive in the context of the well-known attitude towards aging.

Association of Acute Kidney Injury with the Risk of Dementia: A Meta-Analysis

Acute kidney injury (AKI) is associated with several adverse outcomes, including new or progressive chronic kidney disease, end-stage kidney disease, and mortality. Epidemiological studies have reported an association between AKI and dementia as a long-term adverse outcome. This meta-analysis was aimed to understand the association between AKI and dementia risk. A literature search was performed in MEDLINE and Embase databases, from inception to July 2021, to identify epidemiological studies reporting the association between AKI and dementia risk. Title and abstract followed by the full-text of retrieved articles were screened, data were extracted, and quality was assessed, using the Newcastle-Ottawa scale by two investigators independently. The primary outcome was to compute the pooled risk of dementia in AKI patients. Subgroup analysis was also performed based on age and co-morbidities. Certainty of evidence was assessed using the GRADE approach. Statistical analysis was performed using Review Manager 5.4 software. Four studies (cohort (n = 3) and case-control (n = 1)) with a total of 429,211 patients, of which 211,749 had AKI, were identified. The mean age of the patients and the follow-up period were 64.15 ± 16.09 years and 8.9 years, respectively. Included studies were of moderate to high quality. The pooled estimate revealed a significantly higher risk of dementia in AKI patients with an overall relative risk/risk ratio (RR) of 1.92 (95% CI: 1.52-2.43), p ≤ 0.00001. Dementia risk increases by 10% with one year increase in age with an RR of 1.10 (95% CI: 1.09-1.11), p < 0.00001. Subgroup analysis based on stroke as a co-morbid condition also revealed significantly higher dementia risk in AKI patients (RR 2.30 (95% CI: 1.62-3.28), p = 0.009). All-cause mortality risk was also significantly higher in AKI patients with dementia with a pooled RR of 2.11 (95% CI: 1.20-3.70), p = 0.009. The strength of the evidence was of very low certainty as per the GRADE assessment. Patients with AKI have a higher risk of dementia. Further large epidemiological studies are needed to confirm the mechanistic association.

Development and validation of the dialysis dementia risk score: A retrospective, population-based, nested case-control study

Background

Dementia is prevalent and underdiagnosed in the dialysis population. We aimed to develop and validate a simple dialysis dementia scoring system to facilitate identification of individuals who are at high risk for dementia.

Methods

We applied a retrospective, nested case‐control study design using a national dialysis cohort derived from the National Health Insurance Research Database in Taiwan. Patients aged between 40 and 80 years were included and 2940 patients with incident dementia were matched to 29,248 non‐dementia controls. All subjects were randomly divided into the derivation and validation sets with a ratio of 4:1. Conditional logistic regression models were used to identify factors contributing to the risk score. The cutoff value of the risk score was determined by Youden's J statistic and the graphic method.

Results

The dialysis dementia risk score (DDRS) finally included age and 10 comorbidities as risk predictors. The C‐statistic of the model was 0.71 (95% confidence interval [CI] 0.70–0.72). Calibration revealed a strong linear relationship between predicted and observed dementia risk (R² = 0.99). At a cutoff value of 50 points, the high‐risk patients had an approximately three‐fold increased risk of having dementia compared to those with low risk (odds ratio [OR] 3.03, 95% CI 2.78–3.31). The DDRS performance, including discrimination (C‐statistic 0.71, 95% CI 0.69–0.73) and calibration (p value of Hosmer−Lemeshow test for goodness of fit = 0.18), was acceptable during validation. The OR value (2.82, 95% CI 2.37–3.35) was similar to those in the derivation set.

Conclusion

The DDRS system has the potential to serve as an easily accessible screening tool to determine the high‐risk groups who deserve subsequent neurological evaluation in daily clinical practice.

Quasi-cluster randomized trial of a six-month low-intensity group-based resistance exercise for hemodialysis patients on depression and cognitive function: a 12-month follow-up

Objective

This study aimed to examine the effects of a six-month group-based low-intensity resistance exercise program on depression and the cognitive function of hemodialysis patients.

Method

We conducted a quasi-cluster randomized, open-label controlled study from October 2017 to December 2018. Forty-two patients undergoing hemodialysis completed the trial over six months; half participated in the resistance exercise group (n = 21, mean = 74.90 years of age, SD = 2.23, 66.67% female) and the other half were in a stretching control group (n = 21, mean = 72.57 years of age, SD = 2.26, 28.57% female). Depressive symptoms and cognitive function were the primary outcome measures. Behavioral and psychological problems associated with cognitive decline (NPI-Q), subjective insomnia, and exercise self-efficacy were secondary outcomes. Outcomes were measured at baseline, three-month (mid-intervention), six-month (end of intervention), and 12-month (six months after intervention) follow-ups. Linear mixed model analyses were used to determine short-term (immediately after intervention) and long-term (six months after intervention) effects.

Results

In depression, cognitive function, and the NPI-Q, there were no significant effects. In subjective insomnia, a short-term group-by-time interaction in the intervention group compared to the control group was found (ES = .43). However, the effect had disappeared by the 12-month follow-up. In exercise self-efficacy, short- and long-term group-by-time interactions were found. A significant short-term increase in the resistance exercise and a significant decrease in the stretching control was observed (ES = -.83). However, the effect was weakened in the long term (ES = -.38).

Conclusion

The results showed that low-intensity group resistance exercise would reduce subjective insomnia and improve exercise self-efficacy, but the effect was not maintained by six months after the program.

Trial registration: This study was registered on the University Hospital Medical Information Network Clinical Trials Registry (UMIN000029372).

Trial registration:UMIN Japan identifier: UMIN000029372.

A cross-sectional study exploring cognitive impairment in kidney failure

BACKGROUND

Little is known of the prevalence or associated factors of cognitive impairment in people with kidney failure. Assessment of cognition is necessary to inform comprehension of healthcare information, aptitude for dialysis modality and informed decision making.

OBJECTIVES

This study sought to determine the prevalence and factors associated with cognitive impairment in people with kidney failure.

DESIGN

Prospective cross-sectional.

PARTICIPANTS

Participants (n = 222) with chronic kidney disease grade 5 (CKD G5) including those not treated with dialysis, those undertaking dialysis independently or in a facility (CKD 5D), and those with a kidney transplant (CKD 5T).

MEASUREMENTS

Data were collected using the Montreal Cognitive Assessment tool, the Hospital Anxiety and Depression Scale (only the depression subscale), and a demographic questionnaire. Type of kidney disease and comorbidities were extracted from participants' hospital records.

RESULTS

Participants were 61 ± 13.63 years old; most were male (61.26%), and diabetes was the primary cause of kidney disease (34%). Prevalence of cognitive impairment was 34% although it was significantly higher for those in CKD G5 compared with other groups. A number of factors were found to be associated with cognitive impairment including, age, diabetes, hypertension, education, haemoglobin, albumin, parathyroid hormone, CKD G5, and length of time on treatment.

CONCLUSIONS

Cognitive impairment in kidney failure is common and it has significant implications for informed decision making and treatment choices. Routine assessment of cognitive function is an important part of clinical practice.

The effects of dialysis modality choice on cognitive functions in patients with end-stage renal failure: A protocol for systematic review and meta-analysis

BACKGROUND

There is no published meta-analysis comparing the effects of dialysis modality choice on cognitive functions in patients with end-stage renal disease . Therefore, we perform a protocol for systematic review and meta-analysis to evaluate cognitive function in peritoneal dialysis versus hemodialysis patients.

METHODS

This protocol is conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocol (PRISMA-P) statement guidelines. Related articles were identified by searching Web of Science, Embase, PubMed, Wanfang Data, Medline, Science Direct, and Cochrane Library. The risk of bias assessment of the included articles was performed by two authors independently using the tool recommended in the Cochrane Handbook for Systematic Reviews of Interventions. All calculations were carried out with Stata 11.0 (The Cochrane Collaboration, Oxford, United Kingdom).

RESULTS

The results of this systematic review and meta-analysis will be published in a peer-reviewed journal.

CONCLUSION

We hypothesized that patients on peritoneal dialysis demonstrated a lower odd of cognitive dysfunction compared to those on hemodialysis.

OPEN SCIENCE FRAMEWORK REGISTRATION NUMBER

10.17605/OSF.IO/NWCZK.

Feasibility Trial of Cognitive Behavioral Therapy for Fatigue in Hemodialysis (BReF Intervention)

CONTEXT

Fatigue affects at least half of patients who are on hemodialysis (HD) with considerable repercussions on their functioning, quality of life, and clinical outcomes.

OBJECTIVES

This study assessed the feasibility, acceptability, and potential benefits of a cognitive behavioral therapy intervention for renal fatigue (BReF intervention).

METHODS

This was a feasibility randomized controlled trial of the BReF intervention vs. waiting-list control. Outcomes included recruitment, retention, and adherence rates. Exploratory estimates of treatment effect were computed. The statistician was blinded to allocation.

RESULTS

Twenty-four prevalent HD patients experiencing clinical levels of fatigue were individually randomized (1:1) to BReF (N = 12) or waiting-list control arms (N = 12). Fifty-three (16.6%; 95% CI = 12.7-21.1) of 320 patients approached consented and completed the screening questionnaire. It was necessary to approach 13 patients for screening for every one patient randomized. The rate of retention at follow-up was 75% (95% CI = 53.29-90.23). Moderate to large treatment effects were observed in favor of BReF on fatigue severity, fatigue-related functional impairment, depression, and anxiety (standardized mean difference [SMD]_g = 0.81; SMD_g = 0.93; SMD_g = 0.38; SMD_g = 0.42, respectively) but not sleep quality (SMD_g = -0.31). No trial adverse events occurred.

CONCLUSION

There was promising evidence in support of the need and benefits of a cognitive behavioral therapy-based intervention for fatigue in HD. However, uptake was low, possibly as a result of an already high treatment burden in this setting. Considerations on the context of delivery are necessary before pursuing a definitive trial.

CENTRAL NERVOUS SYSTEM RESPONSE TO CHRONIC KIDNEY DISEASE

Due to the aging of the human population, the prevalence of chronic diseases such as chronic kidney disease (CKD) is increasing every year. Chronic kidney disease is a general term that refers to heterogeneous disorders that affect kidney structure and function. Decrease in glomerular filtration can be defined as chronic and progressive deterioration in fluid-solute balance, metabolic and endocrine functions of the kidney. CKD often affects the elderly. With the advancement of age, some structural and functional changes occur in the kidneys. Therefore, the number of patients suffering from mild and moderate CKD is expected to increase in the future.CKD leads to the deep metabolic and hemodynamic changes that damage other organs, such as the heart and brain. CNS abnormalities and cognitive deficits progress with the severity of CBS and occurs mostly among hemodialysis patients. It also has great socio-economic effects on individuals. Since symptoms of CKD are not often found in patients, early recognition of risk factors is the main point. For this reason, it is necessary to identify possible protective and preventive treatments to be applied in at-risk groups and to examine these mechanisms for the treatment of the disease. This review provides available information on the relevant mechanisms.

Altered resting-state functional networks in patients with hemodialysis: a graph-theoretical based study

Recent studies have demonstrated that hemodialysis patients exhibit disruptions in functional networks with invisible cerebral alterations. We explored the alterations of functional connectivity in hemodialysis patients using the graph-theory method. A total of 46 hemodialysis patients (53.11 ± 1.58 years, 28 males) and 47 healthy controls (55.57 ± 0.86 years, 22 males) were scanned by using resting-state functional magnetic resonance imaging. The brains of these patients were divided into 90 regions and functional connectivity was constructed with the automatic anatomical labeling atlas. In the defined threshold range, the graph-theory analysis was performed to compare the topological properties including global, regional and edge parameters between the hemodialysis and the healthy control groups. Both hemodialysis patients and healthy control subjects demonstrated common small-world property of the brain functional connections. At the global level, the parameters normalized clustering coefficients and small-worldness were significantly decreased in hemodialysis patients compared with those noted in healthy controls. At the regional level, abnormal nodal metrics (increased or decreased nodal degree, betweenness centrality and efficiency) were widely found in hemodialysis patients compared with those of healthy controls. The network-based statistical method was employed and two disrupted neural circuits with 18 nodes and 19 edges (P = 0.0139, corrected) and 10 nodes and 11 edges (P = 0.0399, corrected) were detected. Of note, the edge-increased functional connectivity was associated with the salience network and the frontal-temporal-basal ganglia connection, whereas the edge-decreased functional connectivity was associated with the frontoparietal network. The graph-theory method may be one of the potential tools to detect disruptions of cerebral functional connectivity and provide important evidence for understanding the neuropathology of hemodialysis patients from the disrupted network organization perspective.

A Narrative Review of Management Strategies for Common Symptoms in Advanced CKD

Patients with advanced chronic kidney disease (CKD) experience multiple bothersome symptoms, undermining their quality of life (QOL). With growing attention to the importance of symptom management in advanced CKD, the evidence regarding symptoms is increasing. In this review, we briefly summarize the current evidence of effective pharmacologic and nonpharmacologic interventions to improve symptoms and QOL in patients with advanced CKD, including those on dialysis. We focused on symptoms that are commonly experienced by patients, such as pain, fatigue, sleep disturbances, itching, nausea and vomiting, cognitive impairment, and anxiety and depression. We noted that research in symptom science focused on improving symptom management in CKD is still very limited. In addition to the lack of clinical practice guidelines to address those common symptoms, the major gaps in the current literature include the evidence regarding mechanistic pathways to inform the development of effective symptom management for CKD populations, the evidence to confirm effective pharmacologic interventions in other populations for CKD populations, and research on how to incorporate effective symptom management approaches into clinical care. Although improving mortality remains as an important area in the kidney community, there is an urgent need to focus on improving symptom management to improve QOL in advanced CKD.

Structural and Functional Brain Changes in Hemodialysis Patients with End-Stage Renal Disease: DTI Analysis Results and ALFF Analysis Results

Introduction

The current study aimed to depict intrinsic structural changes and the spontaneous brain activity patterns in voxel level in patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD) by using diffusion-tensor imaging and resting-state functional magnetic resonance (MR) imaging with an amplitude of low-frequency fluctuations (ALFF) algorithm and their clinical relevance.

Materials and Methods

In the study, the diffusion-tensor imaging and resting-state functional MR imaging were performed in forty-two hemodialysis patients with ESRD and 42 healthy control subjects. Neuropsychological and laboratory tests were performed in all subjects. ALFF, fraction anisotropy (FA), and mean diffusivity (MD) values were compared between the two groups. Correlations between ALFF, FA or MD values, and clinical markers were analyzed.

Results

We found that ESRD patients exhibited significantly lower ALFF values in multiple areas, including medial frontal gyrus, limbic lobe, superior frontal gyrus, bilateral lingual gyri, occipital lobe, parahippocampal gyrus, precuneus, while increased ALFF values in medial frontal gyrus than healthy controls. FA values were decreased in medial frontal gyrus, parietal lobe, and left precuneus regions in the ESRD group compared with controls. Importantly, FA for the frontal and parietal lobes was negatively associated with the dialysis duration of ESRD patients, ALFF z-scores for the medial prefrontal cortex (MPFC) were positively correlated with the dialysis duration of ESRD patients and Serum calcium of ESRD patients negatively correlated with FA values in the frontal and parietal lobes (p<0.05).

Conclusion

Our study revealed that both impaired brain structure and function in ESRD patients with routine hemodialysis distributed mainly in the parietal, temporal, and frontal lobes. ESRD patients have cognitive impairment and declined memory ability. Serum calcium and dialysis duration might be associated with the impairment of brain structure and function in patients with ESRD.

Perceptions of Illness Severity, Treatment Goals, and Life Expectancy: The ePISTLE Study

Introduction

A better understanding of factors influencing perceived life expectancy (PLE), interactions between patient prognostic beliefs, experiences of illness, and treatment behavior is urgently needed.

Methods

Case-notes at 3 hemodialysis units were screened: patients with ≥20% 1-year mortality risk were included. Patients and their health care professionals (HCPs) were invited to complete a structured interview or mixed-methods questionnaire. Four hundred eleven patient notes were screened. Seventy-seven eligible patients were approached and 51 were included.

Results

Patients predicted significantly higher life expectancies than HCPs (P < 0.0001). Documented cognitive impairment, gender, or increasing age did not affect 1- or 5-year PLE. PLE influenced priorities of care: one-fifth of patients who estimated themselves to have >95% 1-year survival preferred “care focusing on relieving pain and discomfort,” compared with nearly three-quarters of those reporting a ≤50% chance of 1-year survival. Twenty of 51 (39%) patients believed transplantation was an option for them, despite only 4 being waitlisted at the time of the interview. Patients who thought they were transplant candidates were significantly more confident they would be alive at 1 and 5 years and to want resuscitation attempted. Cognitive impairment had no effect on perceived transplant candidacy. A high symptom burden was present and underrecognized by HCPs. High symptom burden was associated with significantly lower PLE at both 1 and 5 years, increased anxiety/depression scores, and treatment choices more likely to prioritize relief of suffering.

Conclusion

There is a disparity between patient PLE and those of their HCPs. Severity of symptom burden and beliefs regarding PLE or transplant candidacy affect patient treatment preferences.

Effect of uremic toxins on hippocampal cell damage: analysis in vitro and in rat model of chronic kidney disease

One third of the patients with chronic kidney disease (CKD) develop cognitive impairment, which is also an independent risk factor for mortality. However, the concise mechanism of cerebro-renal interaction has not been clarified. The present study examines the effects of uremic toxins on neuronal cells and analyzes the pathological condition of the brain using mouse hippocampal neuronal HT-22 cells and adenine-induced CKD model rats. Among the uremic toxins analyzed, indoxyl sulfate, indole, 3-indoleacetate, and methylglyoxal significantly decreased viability and glutathione level in HT-22 cells. The mixture of these uremic toxins also decreased viability and glutathione level at a lower dose. Adenine-induced CKD rat showed marked renal damage, increased urinary oxidative stress markers, and increased numbers of pyknotic neuronal cells in hippocampus. CKD rats with damaged hippocampus demonstrated poor learning process when tested using the Morris water maze test. Our results suggest that uremic toxins have a toxic effect on hippocampal neuronal cells and uremic CKD rats shows pyknosis in hippocampus.

Association between Cerebral Oxygenation, as Evaluated with Near-Infrared Spectroscopy, and Cognitive Function in Patients Undergoing Hemodialysis

INTRODUCTION

The prevalence of cognitive impairment in patients undergoing hemodialysis (HD) is higher than that in healthy controls. To date, studies on the association between cognitive function and cerebral oxygenation in these patients are limited. Therefore, in this study, we aimed to cross-sectionally investigate the association between cognitive assessment scores and clinical factors, including cerebral oxygenation, in patients undergoing HD.

METHODS

In this observational study, 193 HD patients were included. Cerebral regional oxygen saturation (rSO2) was monitored using an INVOS 5,100c oxygen saturation monitor. Poor cognition was defined as a Mini-Mental State Examination (MMSE) score ≤23. We analyzed the association between MMSE score and clinical factors, including cerebral rSO2.

RESULTS

MMSE score in HD patients included in this study was 26.8 ± 3.3. There were 164 patients (85%) with MMSE score ≥24 and 29 patients (15%) with an MMSE score ≤23. In the patients with MMSE score ≥24, cerebral rSO2 (53.8% ± 8.3%) was significantly higher than that in patients with MMSE score ≤23 (49.5% ± 9.8%; p = 0.013). Multivariable linear regression analysis was performed using the following confounding factors: age, mean blood pressure, cerebral rSO2, HD duration, ultrafiltration rate, hemoglobin, serum Cr, serum calcium, serum phosphate, total cholesterol, high-density lipoprotein cholesterol levels, serum albumin, presence of diabetes mellitus or chronic glomerulonephritis, history of comorbid cardiovascular or cerebrovascular disease, and use of renin-angiotensin-aldosterone system inhibitors or vitamin D analogs. MMSE score was independently and significantly associated with age (standardized coefficient: -0.244) and cerebral rSO2 (standardized coefficient: 0.180).

CONCLUSIONS

MMSE score was independently associated with age (negative effect) and cerebral rSO2 (positive effect) in this cross-sectional study. Further prospective studies are needed to clarify whether maintaining cerebral oxygenation prevents the deterioration of cognitive function in patients undergoing HD.

Review of the structural and functional brain changes associated with chronic kidney disease

Chronic kidney disease (CKD) leads to profound metabolic and hemodynamic changes, which damage other organs, such as heart and brain. The brain abnormalities and cognitive deficit progress with the severity of the CKD and are mostly expressed among hemodialysis patients. They have great socio-economic impact. In this review, we present the current knowledge of involved mechanisms.

Intradialytic hypotension and relationship with cognitive function and brain morphometry

Background

The haemodynamic stress brought about by dialysis could justify the loss of structural and functional integrity of the central nervous system (CNS). The main objective of this study was to analyse the relationship between intradialytic hypotension (IDH) and cognitive function and brain morphometry.

Methods

The cross-sectional KIDBRAIN study (Cohort Study of Morphological Changes of the Brain by MRI in Chronic Kidney Disease Patients) included 68 prevalent patients with no history of neurological disorders (cerebrovascular disease and cognitive impairment) undergoing haemodialysis (HD). We analysed 18 non-consecutive dialysis sessions (first three of each month over a 6-month period) and various definitions of IDH were recorded. Global cognitive function (GCF) was assessed using the Mini-Mental State Examination (MMSE) and parameters of structural integrity of the CNS were obtained using volume morphometry magnetic resonance imaging analysis [grey matter (GM), white matter (WM) and hippocampus).

Results

A greater number of sessions with IDH were associated with less volume of WM (r = −0.359,P = 0.003) and hippocampus (r = −0.395, P = 0.001) independent of cardiovascular risk factors according to multivariable linear regression models (β = −0.198, P = 0.046 for WM; β = −0.253, P = 0.017 for hippocampus). The GCF by the MMSE was 27.3 ± 7.3.1 and was associated with WM volume (β = 0.403, P = 0.001) independent of GM and hippocampus volume. Symptomatic IDH was associated with GCF (r = −0.420, P < 0.001) in adjusted analysis (β = −0.339, P = 0.008).

Conclusions

Even when asymptomatic, IDH is associated with a lower WM and hippocampus volume and reduced GCF in patients undergoing HD, thus suggesting greater vulnerability of the brain to the haemodynamic stress that may be generated by a dialysis session.

Cognitive impairment in patients with moderate to severe chronic kidney disease: the Salford kidney cohort study

Background

Cognitive impairment in chronic kidney disease (CKD) is common and underrecognized [1, 2]. Determining risk factors for cognitive impairment and whether speed of CKD progression is an important consideration may help identify cognitive impairment by nephrologists. Vascular disease is thought to underpin cognitive impairment in CKD and by segregating CKD patients with proven vascular disease, we may also be able to discover other important associations with cognitive impairment in CKD patients.

Method

A total of 250 patients in a UK prospective cohort of CKD patients underwent two cognitive assessments: Montreal Cognitive Assessment test and Trail Making Test. Cognitive impairment was defined using validated population cut-offs (cognitive impairment) and relative cognitive impairment. Relative cognitive impairment was defined by <1 standard deviation below the mean Z-score on any completed test. Two multivariable logistical regression models identified variables associated with cognitive impairment and realtive cognitive impairment.

Results

About 44 and 24.8% of patients suffered cognitive impairment and relative cognitive impairment, respectively. Depression, previous stroke and older age were significantly associated with cognitive impairment. Older age was significantly associated with relative cognitive impairment (P ≤ 0.05) and higher proteinuria and the use of psychodynamic medications were also significantly associated with relative cognitive impairment (P = 0.05). Delta estimated glomerular filtration rate (eGFR) in patients with cognitive impairment and relative cognitive impairment compared with those having normal cognition was similar (−0.77 versus −1.35 mL/min/1.73 m²/year, P = 0.34 for cognitive impairment and −1.12 versus −1.02 mL/min/1.73 m²/year, P = 0.89 for relative cognitive impairment).

Conclusion

Risk factors for cognitive impairment in CKD include previous stroke, depression or anxiety, higher proteinuria and prescription of psychodynamic medications. Patients with a faster eGFR decline do not represent a group of patients at increased risk of cognitive impairment.

Mutual Interaction of Clinical Factors and Specific microRNAs to Predict Mild Cognitive Impairment in Patients Receiving Hemodialysis

Cognitive impairment (CI) is not uncommon in dialysis patients. Various factors have been implicated. This study aims to examine mutual interaction of various clinical factors for CI in patients receiving hemodialysis. A total of 48 hemodialysis patients in outpatient clinic were recruited from 2015 to 2017. Demographics, circulating uremic toxin concentrations, miRNA concentrations, and nerve injury protein concentrations were collected. Clinical dementia rating (CDR) scores were used to stratify the functional scores of the patients. Receiver operating characteristic (ROC) analysis was used to evaluate diagnostic test performance for predicting dichotomous results, and cumulative ROC analysis was used to examine the combined contribution of clinical factors. CDR scale 0 included 15 patients (mean age, 59.1 years); CDR > 0.5 included 33 patients (mean age, 64.0 years). On cumulative ROC analysis, the major predictors of mild CI were hemoglobin, age, sex, homocysteine, neuron-specific enolase (NSE), and miR-486. The cumulative area under the curve (AUC) on combining hemoglobin, age, and miR-486 was the highest (0.897, 95% confidence interval 0.806–0.988). Two dichotomized variables reached 81.82% sensitivity and 86.67% specificity, with the likelihood ratio for positive and negative results being 6.14 and 0.21, respectively. In conclusion, hemoglobin, age, and miR-486 display high-degree combined effects on mild CI in patients receiving hemodialysis.

Comparison of Performance on the Clock Drawing Test Using Three Different Scales in Dialysis Patients

Background

The clock drawing test (CDT) is frequently used to detect changes in cognition. Multiple scales of varying length have been published to assess performance. The aim of this study is to compare the CDT performance measured by three scales among a sample of nondemented patients on renal dialysis and identify the variables that affect performance. Methodology. This is a cross-sectional study performed at the dialysis unit at King Saud University Medical City. Eighty-nine dialysis patients performed the CDT. The CDT was scored by the methods of Rouleau et al. (RCS 10-point), Babins et al. (BCS 18-point), and the MoCA (MCS 3-point). Regression models were used to determine influencing demographic and dialysis variables. Scores were then correlated, and a combined factor analysis of scale components was done.

Results

Females represented 44.6%, the mean (SD) age was 49.99 (15.49) years, and education duration was 10.29 (5.5) years. Dialysis vintage was 55.81 (62.91) months. The scores for the MCS, RCS, and BCS were 2.18 (1.08), 6.67 (3.07), and 11.8 (5.5), respectively, with significant correlation (P < 0.0001). In all scales, increasing age was associated with a lower score (each P < 0.0001). The scores increased with increasing education (each P < 0.0001). Diabetics had a lower score on both the BCS and MCS by 2.56 (SE 1.2) (P = 0.035) and 0.71 (P = 0.003) points, respectively. However, only age and years of education were significant in the multivariable analysis. In factor analysis, two shared factors appeared between the three scales: hand and number placement and the clock face.

Conclusion

Age and education influence the performance on the CDT, and factors diverged into executive and visuospatial components. The MCS is likely to yield useful information but should be interpreted as part of the MoCA.

Decline in kidney function over the course of adulthood and cognitive function in midlife

OBJECTIVE

To test the hypothesis that end-stage renal disease (ESRD) risk exposure during young adulthood is related to worse cognitive performance in midlife.

METHODS

We included 2,604 participants from the population-based Coronary Artery Risk Development in Young Adults (CARDIA) Study (mean age 35 years, 54% women, 45% Black). Estimated glomerular filtration rate and albumin-to-creatinine ratio were measured every 5 years at year (Y) 10 through Y30. At each visit, moderate/high risk of ESRD according to the Kidney Disease: Improving Global Outcomes guidelines (estimated glomerular filtration rate <60 mL/min/1.73 m² or albumin-to-creatinine ratio >30 mg/g) was defined, totaled over examinations, and categorized into 0 episodes, 1 episode, and >1 episodes of ESRD risk. At Y30, participants underwent global and multidomain cognitive assessment. We used analysis of covariance to assess the association of ESRD risk categories with cognitive function, controlling for cardiovascular risk factors.

RESULTS

Over the course of 20 years, 427 participants (16% of the study population) had ≥1 episodes of ESRD risk exposure. Individuals with more risk episodes had lower composite cognitive function (p < 0.001), psychomotor speed (p < 0.001), and executive function (p = 0.007). All these associations were independent of sociodemographic status and cardiovascular risk factors.

CONCLUSIONS

In this population-based longitudinal study, we show that episodes of decline in kidney function over the young-adulthood course are associated with worse cognitive performance at midlife. Preserving kidney function in young age needs to be investigated as a potential strategy to preserve cognitive function in midlife.

Alterations of Spontaneous Brain Activity in Hemodialysis Patients

Cognitive impairment is prevalent in hemodialysis end-stage renal disease (ESRD) patients. It might be associated with poor prognosis. Nevertheless, the underlying mechanisms have not been completely clarified. This study explored spontaneous brain activity in ESRD patients on hemodialysis by using the amplitude of low-frequency fluctuation (ALFF). Nineteen ESRD patients on regular hemodialysis were included in this study. Eighteen age-, sex- and education level-matched volunteers were enrolled as the healthy control group. All participants had resting-state functional MRI scanning, neuropsychological tests, and laboratory testing. ALFF was used for assessing intrinsic brain activity. Independent samples t-test was used for obtaining group differences. Spearman correlation analysis was applied to assess the association between ALFF changes, neuropsychological, and clinical indices. Compared to the healthy control group, hemodialysis patients showed decreased ALFF in the precuneus, right angular gyrus/inferior lobule as well as increased ALFF in the left parahippocampus/hippocampus and right precentral/postcentral gyrus. The ALFF abnormalities in these regions were closely associated with hemoglobin levels. Also, increased ALFF in the left parahippocampus/hippocampus showed a negative correlation with the score of long-delayed free recall. Hemodialysis patients had aberrant ALFF in the default mode network (DMN) regions, particularly in the precuneus and parahippocampus/hippocampus, which may be correlated with neuropathological mechanisms involved in hemodialysis.

Delirium is independently associated with early mortality in elderly patients starting hemodialysis

BACKGROUND

Delirium is an independent predictor of death in patients undergoing dialysis for end-stage renal disease (ESRD). However, it is unknown whether delirium during hospitalization at the start of hemodialysis (HD) in elderly populations is associated with early mortality.

METHODS

We conducted a retrospective cohort study to investigate the association between delirium and early mortality in the elderly after starting HD. The cohort consisted of patients ≥ 75 years who started dialysis for ESRD at the National Center for Global Health and Medicine from 2010 to 2017 and at Yokosuka Kyosai Hospital from 2007 to 2011. Delirium was defined as patients who showed new symptoms of transient confused thinking and reduced awareness of their environment and were prescribed antipsychotic medications. The primary outcome was death within 1 year. Data were analyzed using Cox proportional hazard models with adjustments for baseline characteristics. A multinomial logistic regression was used to identify the determinants of patients developing delirium.

RESULTS

We enrolled 259 patients (males, 60%); 33 patients were diagnosed with delirium. The primary outcome was observed in 19 patients with delirium (58%) and 24 patients without delirium (11%) (p < 0.01). Delirium was independently associated with all-cause mortality within 1 year after starting HD (hazard ratio 7.82, 95% confidence interval 4.26-14.3; adjusted hazard ratio 7.16, 95% confidence interval 3.49-14.7). Delirium was positively correlated with "cognitive impairment" as well as "the use of steroids."

CONCLUSION

Delirium is independently associated with early mortality in the elderly after starting HD.

Associations between small and middle molecules clearance and the change of cognitive function in peritoneal dialysis

BACKGROUND

Uremic toxins have been suspected as potential contributors for cognitive impairment in peritoneal dialysis (PD) patients. However, associations between the clearance of serum small and middle molecules and the change of cognitive function were not fully explored and then we explored this issue in the present study.

METHOD

A total of clinically-stable 222 patients on PD were enrolled and then followed up for 2 years in this single-center prospective cohort study. Small and middle molecules clearances were examined by urea clearance (Kt/V), creatinine clearance (Ccr) and beta-2 microglobulin (B2M) clearance via dialysate and urine at baseline and after 2 years. Global and specific cognitive impairment were measured at baseline and after 2 years. Modified Mini-Mental State Examination (3MS) was assessed for global cognitive function, trail-making tests A and B for executive function and subtests of the battery for the assessment of neuropsychological status for immediate and delayed memory, visuospatial skills and language ability.

RESULTS

The median of total Kt/V, Ccr and B2M clearance were 1.89, 53.2 l/w/1.73 m2 and 17.5 l/w/1.73 m2, respectively at baseline. The prevalence of global cognitive impairment was 12.3% for 222 patients and 15.4% for the remained 130 patients after 2 years. At baseline, total Kt/V was independently positively associated with delayed memory function. Total and dialysate beta-2 microglobulin clearance was positively associated with 3MS scores and negatively with completion time on trail A after multivariate adjustment. At 2 years, we observed a significant difference in the changing trend of 3MS scores between groups divided by total B2M clearance (P = 0.033), which still maintained to be meaningful after multivariate adjustment (P = 0.024). Patients with total B2M clearance > 19.0 l/w/1.73 m2 got significant improvement on their 3MS scores (P = 0.005). Patients divided by total Kt/V or Ccr were not significantly different in the trends of general and any specific cognitive function during the follow up.

CONCLUSION

The higher middle molecules clearance independently correlated to better performance on general cognitive and executive function in PD patients, which also predict an improvement in general cognitive function during the follow up.

Prevalence, Types and Recognition of Cognitive Impairment in Dialysis Patients in South Eastern Sydney

BACKGROUND

In international studies, cognitive impairment is a common but underdetected issue in dialysis patients. Chronic Kidney Disease (CKD) shares risk factors with and is an independent risk factor for cognitive impairment. There is a lack of Australian data of cognitive impairment in this at-risk population. This has implications on service planning because cognitive impairment in CKD is associated with higher mortality, morbidity, and healthcare costs.

AIMS

This study examines the prevalence, types, and clinician recognition of cognitive impairment within an Australian dialysis population.

METHODS

A cross-sectional study of haemodialysis and peritoneal dialysis patients in South-East Sydney screened for cognitive impairment using the Montreal Cognitive Assessment (MoCA). Participant interviews, medical records, physician and carer questionnaires, were used to determine the types of cognitive impairment and rate of recognition.

RESULTS

106 participants were included (median age 66 years, median dialysis duration 2 years) and 58 (54.7%) were cognitively impaired on the MoCA, of whom old age psychiatrists subclassified 21 (36.2%) as having dementia, and 31 (53.4%) with 'Cognitive Impairment, No Dementia'. 36/58 (62.0%) of the cognitively impaired participants on the MoCA were suspected of having cognitive impairment by nephrologists but only 14/58 (24.1%) had this documented in medical records.

CONCLUSION

Although cognitive impairment is common in dialysis patients, there are low levels of detection by clinical teams. Cognitive screening of dialysis patients should be incorporated as part of wider assessment and determination of management goals such as individuals' capacity to self-care and provide informed consent to treatments. This article is protected by copyright. All rights reserved.

Cognitive Function, Access to Kidney Transplantation, and Waitlist Mortality Among Kidney Transplant Candidates With or Without Diabetes

RATIONALE & OBJECTIVE

Intact cognition is generally a prerequisite for navigating through and completing evaluation for kidney transplantation. Despite kidney transplantation being contraindicated for those with severe dementia, screening for more mild forms of cognitive impairment before referral is rare. Candidates may have unrecognized cognitive impairment, which may prolong evaluation, elevate mortality risk, and hinder access to kidney transplantation. We estimated the burden of cognitive impairment and its association with access to kidney transplantation and waitlist mortality.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

3,630 participants (January 2009 to June 2018) with cognitive function measured (by the Modified Mini-Mental State Examination [3MS]) at kidney transplantation evaluation at 1 of 2 transplantation centers.

PREDICTORS

Cognitive impairment (3MS score<80).

OUTCOMES

Listing, waitlist mortality, and kidney transplantation.

ANALYTICAL APPROACH

We estimated the adjusted chance of listing (Cox regression), risk for waitlist mortality (competing-risks regression), and kidney transplantation rate (Poisson regression) by cognitive impairment. Given potential differences in cause of cognitive impairment among those with and without diabetes, we tested whether these associations differed by diabetes status using a Wald test.

RESULTS

At evaluation, 6.4% of participants had cognitive impairment, which was independently associated with 25% lower chance of listing (adjusted HR, 0.75; 95% CI, 0.61-0.91); this association did not differ by diabetes status (Pinteraction=0.07). There was a nominal difference by diabetes status for the association between cognitive impairment and kidney transplantation rate (Pinteraction=0.05), while the association between cognitive impairment and waitlist mortality differed by diabetes status kidney transplantation rates (Pinteraction=0.02). Among candidates without diabetes, those with cognitive impairment were at 2.47 (95% CI, 1.31-4.66) times greater risk for waitlist mortality; cognitive impairment was not associated with this outcome among candidates with diabetes.

LIMITATIONS

Single measure of cognitive impairment.

CONCLUSIONS

Cognitive impairment is associated with a lower chance of being placed on the waitlist, and among patients without diabetes, with increased mortality on the waitlist. Future studies should investigate whether implementation of screening for cognitive impairment improves these outcomes.

Disturbed neurovascular coupling in hemodialysis patients

Background

Altered cerebral blood flow (CBF) and amplitude of low-frequency fluctuation (ALFF) have been reported in hemodialysis patients. However, neurovascular coupling impairments, which provide a novel insight into the human brain, have not been reported in hemodialysis patients.

Methods

We combined arterial spin labeling (ASL) and blood oxygen level dependent (BOLD) techniques to investigate neurovascular coupling alterations and its relationships with demographic and clinical data in 46 hemodialysis patients and 47 healthy controls. To explore regional neuronal activity, ALFF was obtained from resting-state functional MRI. To measure cerebral vascular response, CBF was calculated from ASL. The across-voxel CBF-ALFF correlations for global neurovascular coupling and CBF/ALFF ratio for regional neurovascular coupling were compared between hemodialysis patients and healthy controls. Two-sample t-tests were used to compare the intergroup differences in CBF and ALFF. Multiple comparisons were corrected using a voxel-wise false discovery rate (FDR) method (P < 0.05).

Results

All hemodialysis patients and healthy controls showed significant across-voxel correlations between CBF and ALFF. Hemodialysis patients showed a significantly reduced global CBF-ALFF coupling (P = 0.0011) compared to healthy controls at the voxel-level. Of note, decreased CBF/ALFF ratio was exclusively located in the bilateral amygdala involved in emotional regulation and cognitive processing in hemodialysis patients. In hemodialysis patients, the decreased CBF (right olfactory cortex, anterior cingulate gyrus and bilateral insula) and ALFF (bilateral precuneus and superior frontal gyrus) were mainly located in the default mode network and salience network-related regions as well as increased CBF in the bilateral thalamus.

Conclusions

These novel findings reveal that disrupted neurovascular coupling may be a potential neural mechanism in hemodialysis patients.

Associations of Bone Turnover Markers with Cognitive Function in Patients Undergoing Hemodialysis

BACKGROUND

Patients undergoing hemodialysis experience a greater risk of cognitive impairment than the general population, but limited data elucidates the biomarkers on this. We evaluated the association of bone turnover markers on cognitive function among 251 prevalent hemodialysis enrollees in a cross-sectional study.

METHODS

251 hemodialysis patients (median age = 57.8, 55% men) and 37 control subjects (mean age = 61.2, 56% men) without a prior stroke or dementia diagnosis were enrolled. Serum concentrations of 8 bone markers were analyzed as the association of cognitive function (Montreal Cognitive Assessment (MoCA) and Cognitive Abilities Screening Instrument (CASI)) using linear regression analysis.

RESULTS

A lower cognitive function was noted in hemodialysis patients compared to control subjects. The receptor activator of nuclear factor kappa-B ligand (RANKL) was the only bone marker found to be associated with cognitive function (MoCA and CASI tests) in hemodialysis patients without a prior stroke or dementia diagnosis. In stepwise multiple linear regression analysis, the association remained significant in MoCA (β = 1.14, 95% CI 0.17 to 2.11) and CASI (β = 3.06, 95% CI 0.24 to 5.88). Short-term memory (β = 0.52, 95% CI 0.01 to 1.02), mental manipulation (β = 0.51, 95% CI 0.05 to 0.96), and abstract thinking (β = 0.57, 95% CI 0.06 to 1.09) were the significant subdomains in the CASI score related to RANKL.

CONCLUSIONS

Serum RANKL levels were potentially associated with better cognitive function in hemodialysis patients. Further large-scale and prospective studies are needed to confirm our findings.

Harnessing digital health to objectively assess cognitive impairment in people undergoing hemodialysis process: The Impact of cognitive impairment on mobility performance measured by wearables

Cognitive impairment is prevalent but still poorly diagnosed in hemodialysis adults, mainly because of the impracticality of current tools. This study examined whether remotely monitoring mobility performance can help identifying digital measures of cognitive impairment in hemodialysis patients. Sixty-nine diabetes mellitus hemodialysis patients (age = 64.1±8.1years, body mass index = 31.7±7.6kg/m2) were recruited. According to the Mini-Mental State Exam, 44 (64%) were determined as cognitive-intact, and 25 (36%) as cognitive-impaired. Mobility performance, including cumulated posture duration (sitting, lying, standing, and walking), daily walking performance (step and unbroken walking bout), as well as postural-transition (daily number and average duration), were measured using a validated pendant-sensor for a continuous period of 24-hour during a non-dialysis day. Motor capacity was quantified by assessing standing balance and gait performance under single-task and dual-task conditions. No between-group difference was observed for the motor capacity. However, the mobility performance was different between groups. The cognitive-impaired group spent significantly higher percentage of time in sitting and lying (Cohens effect size d = 0.78, p = 0.005) but took significantly less daily steps (d = 0.69, p = 0.015) than the cognitive-intact group. The largest effect of reduction in number of postural-transition was observed in walk-to-sit transition (d = 0.65, p = 0.020). Regression models based on demographics, addition of daily walking performance, and addition of other mobility performance metrics, led to area-under-curves of 0.76, 0.78, and 0.93, respectively, for discriminating cognitive-impaired cases. This study suggests that mobility performance metrics could be served as potential digital biomarkers of cognitive impairment among hemodialysis patients. It also highlights the additional value of measuring cumulated posture duration and postural-transition to improve the detection of cognitive impairment. Future studies need to examine potential benefits of mobility performance metrics for early diagnosis of cognitive impairment/dementia and timely intervention.

Mechanisms of cognitive dysfunction in CKD

Cognitive impairment is an increasingly recognized major cause of chronic disability and is commonly found in patients with chronic kidney disease (CKD). Knowledge of the relationship between kidney dysfunction and impaired cognition may improve our understanding of other forms of cognitive dysfunction. Patients with CKD are at an increased risk (compared with the general population) of both dementia and its prodrome, mild cognitive impairment (MCI), which are characterized by deficits in executive functions, memory and attention. Brain imaging in patients with CKD has revealed damage to white matter in the prefrontal cortex and, in animal models, in the subcortical monoaminergic and cholinergic systems, accompanied by widespread macrovascular and microvascular damage. Unfortunately, current interventions that target cardiovascular risk factors (such as anti-hypertensive drugs, anti-platelet agents and statins) seem to have little or no effect on CKD-associated MCI, suggesting that the accumulation of uraemic neurotoxins may be more important than disturbed haemodynamic factors or lipid metabolism in MCI pathogenesis. Experimental models show that the brain monoaminergic system is susceptible to uraemic neurotoxins and that this system is responsible for the altered sleep pattern commonly observed in patients with CKD. Neural progenitor cells and the glymphatic system, which are important in Alzheimer disease pathogenesis, may also be involved in CKD-associated MCI. More detailed study of CKD-associated MCI is needed to fully understand its clinical relevance, underlying pathophysiology, possible means of early diagnosis and prevention, and whether there may be novel approaches and potential therapies with wider application to this and other forms of cognitive decline.

Evaluation of Screening Tests for Cognitive Impairment in Patients Receiving Maintenance Hemodialysis

BACKGROUND

Neurocognitive testing shows that cognitive impairment is common among patients receiving maintenance hemodialysis. Identification of a well performing screening test for cognitive impairment might allow for broader assessment in dialysis facilities and thus optimal delivery of education and medical management.

METHODS

From 2015 to 2018, in a cohort of 150 patients on hemodialysis, we performed a set of comprehensive neurocognitive tests that included the cognitive domains of memory, attention, and executive function to classify whether participants had normal cognitive function versus mild, moderate, or severe cognitive impairment. Using area-under-the-curve (AUC) analysis, we then examined the predictive ability of the Mini Mental State Examination, the Modified Mini Mental State Examination, the Montreal Cognitive Assessment, the Trail Making Test Part B, the Mini-Cog test, and the Digit Symbol Substitution Test, determining each test's performance for identifying severe cognitive impairment.

RESULTS

Mean age was 64 years; 61% were men, 39% were black, and 94% had at least a high-school education. Of the 150 participants, 21% had normal cognitive function, 17% had mild cognitive impairment, 33% had moderate impairment, and 29% had severe impairment. The Montreal Cognitive Assessment had the highest overall predictive ability for severe cognitive impairment (AUC, 0.81); a score of ≤21 had a sensitivity of 86% and specificity of 55% for severe impairment, with a negative predictive value of 91%. The Trails B and Digit Symbol tests also performed reasonably well (AUCs, 0.73 and 0.78, respectively). The other tests had lower predictive performances.

CONCLUSIONS

The Montreal Cognitive Assessment, a widely available and brief cognitive screening tool, showed high sensitivity and moderate specificity in detecting severe cognitive impairment in patients on maintenance hemodialysis.

Uric acid is associated with cognitive impairment in the elderly patients receiving maintenance hemodialysis-A two-center study

BACKGROUND

Elevated serum uric acid (SUA) has been associated with vascular cognitive impairment (CI) in the elderly. However, its relationship with cognitive function in the elderly patients receiving maintenance hemodialysis (MHD) has not yet been elucidated.

OBJECTIVE

The cognitive impairment is prevalent in MHD patients. Various insults may contribute to cognitive impairment in patients with MHD. The aim of this study was to investigate the relationship between SUA and CI in the elderly patients receiving MHD.

METHODS

A total of 180 elderly MHD subjects from two hospitals were enrolled in our study. Cognitive function domains were evaluated by MMSE at the beginning of the trial. Demographic and clinical characteristics were collected and recorded.

RESULTS

The subjects were stratified into quartiles according to SUA level. Demographic and clinical characteristics such as age, gender, smoking habit, education year, blood pressure (BP), hemoglobin, albumin, blood glucose (BG), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), blood urea nitrogen (BUN), and serum creatinine (Scr) did not differ dramatically among groups (p > .05). The Q1 group showed the highest MMSE scores, and the Q4 group showed the lowest MMSE sores (p < .05). There was a negative correlation between SUA and MMSE scores (r = -.307, p = .014), and this correlation was independent of demographic and clinical characteristics.

CONCLUSIONS

Elevated SUA maybe contributes to CI in the elderly MHD patients. SUA level is independent risk for the CI in the elderly MHD patients.

Berberine for prevention of dementia associated with diabetes and its comorbidities: A systematic review

BACKGROUND

A growing number of epidemiological studies indicate that metabolic syndrome (MetS) and its associated features play a key role in the development of certain degenerative brain disorders, including Alzheimer's disease and vascular dementia. Produced by several different medicinal plants, berberine is a bioactive alkaloid with a wide range of pharmacological effects, including antidiabetic effects. However, it is not clear whether berberine could prevent the development of dementia in association with diabetes.

OBJECTIVE

To give an overview of the therapeutic potential of berberine as a treatment for dementia associated with diabetes.

SEARCH STRATEGY

Database searches A and B were conducted using PubMed and ScienceDirect. In search A, studies on berberine's antidementia activities were identified using "berberine" and "dementia" as search terms. In search B, recent studies on berberine's effects on diabetes were surveyed using "berberine" and "diabetes" as search terms.

INCLUSION CRITERIA

Clinical and preclinical studies that investigated berberine's effects associated with MetS and cognitive dysfunction were included.

DATA EXTRACTION AND ANALYSIS

Data from studies were extracted by one author, and checked by a second; quality assessments were performed independently by two authors.

RESULTS

In search A, 61 articles were identified, and 22 original research articles were selected. In search B, 458 articles were identified, of which 101 were deemed relevant and selected. Three duplicates were removed, and a total of 120 articles were reviewed for this study. The results demonstrate that berberine exerts beneficial effects directly in the brain: enhancing cholinergic neurotransmission, improving cerebral blood flow, protecting neurons from inflammation, limiting hyperphosphorylation of tau and facilitating β-amyloid peptide clearance. In addition, evidence is growing that berberine is effective against diabetes and associated disorders, such as atherosclerosis, cardiomyopathy, hypertension, hepatic steatosis, diabetic nephropathy, gut dysbiosis, retinopathy and neuropathy, suggesting indirect benefits for the prevention of dementia.

CONCLUSION

Berberine could impede the development of dementia via multiple mechanisms: preventing brain damages and enhancing cognition directly in the brain, and indirectly through alleviating risk factors such as metabolic dysfunction, and cardiovascular, kidney and liver diseases. This study provided evidence to support the value of berberine in the prevention of dementia associated with MetS.

Alterations in Structural and Functional Connectivities in Patients with End-Stage Renal Disease

Background and Purpose

The aim of this study was to evaluate the structural and functional connectivities of brain network using graph theoretical analysis in neurologically asymptomatic patients with end-stage renal disease (ESRD). We further investigated the prevalence of cognitive impairment (CI) in ESRD patients and analyzed the association between network measures of brain connectivity and cognitive function.

Methods

We prospectively enrolled 40 neurologically asymptomatic ESRD patients, 40 healthy controls, and 20 disease controls. All of the subjects underwent diffusion-tensor imaging (DTI) and resting-state functional magnetic resonance imaging (rs-fMRI). We calculated measures of structural and functional connectivities based on DTI and rs-fMRI, respectively, and investigated differences therein between the ESRD patients and the healthy controls. We assessed cognitive function in the ESRD patients using the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease neuropsychological battery.

Results

The ESRD patients exhibited decreased global structural and functional brain connectivities, as well as alterations of network hubs compared to the healthy controls and disease controls. About 70% of the ESRD patients had CI. Moreover, ESRD patients without CI exhibited decreased global connectivity and alterations of network hubs. Furthermore, there was a significant positive association between measures of brain connectivity and cognitive function.

Conclusions

We found that ESRD patients exhibited decreased structural and functional brain connectivities, and that there was a significant association between brain connectivity and cognitive function. These alterations in the brain network may contribute to the pathophysiological mechanism of CI in ESRD patients.

Protein-bound uremic toxins are associated with cognitive function among patients undergoing maintenance hemodialysis

Patients with chronic kidney disease have a greater risk of cognitive impairment. Cerebral uremic solute accumulation causes uremic encephalopathy; however, the association of protein-bound uremic toxins on cognitive function remains unclear. The present study aimed to investigate the association of two protein-bound uremic toxins, namely indoxyl sulfate (IS) and p-cresyl sulfate (PCS), on cognitive function in patients receiving hemodialysis (HD) for at least 90 days. Circulating free form IS and PCS were quantified by liquid chromatography/mass spectrometry. Mini-Mental State Examination (MMSE) and Cognitive Abilities Screening Instrument (CASI) were used to evaluate cognitive function. In total, 260 HD patients were recruited with a mean age of 58.1 ± 11.3 years, of which, 53.8% were men, 40% had diabetes, and 75.4% had hypertension. The analysis revealed that both free IS and free PCS were negatively associated with the CASI score and MMSE. After controlling for confounders, circulating free IS levels persisted to be negatively associated with MMSE scores [β = −0.62, 95% confidence interval (CI): −1.16 to −0.08] and CASI scores (β = −1.97, 95% CI: −3.78 to −0.16), mainly in the CASI domains of long-term memory, mental manipulation, language ability, and spatial construction. However, there was no correlation between free PCS and total MMSE or total CASI scores after controlling for confounders. In conclusion, circulating free form IS, but not PCS is associated with lower cognitive function test scores in HD patients. Thus, a further study is needed to evaluate whether a decrease in free IS levels can slow down cognitive decline in HD patients.

Altered functional connectivity density in the brains of hemodialysis end-stage renal disease patients: An in vivo resting-state functional MRI study

Background

End-stage renal disease (ESRD) patients usually suffer from a high prevalence of central nervous system abnormalities, including cognitive impairment and emotional disorders, which severely influence their quality of life. There have been many neuroimaging research developments in ESRD patients with brain function abnormalities; however, the dysfunction of the salience network (SN) of them has received little attention. The purpose of this study was to investigate the changes of global functional connectivity density (gFCD) in brains of ESRD patients undergoing hemodialysis using resting-state functional magnetic resonance imaging (re-fMRI).

Methods

re-fMRI data were collected from 30 ESRD patients undergoing hemodialysis (14 men, 38.33±7.44 years old) and 30 matched healthy controls (13 men, 39.17±5.7 years old). Neuropsychological tests including the Montreal Cognitive Assessment (MoCA) and Beck Depression Inventory (BDI) were used to evaluate the neurocognitive and psychiatric conditions of the subjects. Blood biochemistry tests, including hemoglobin level, serum albumin level, blood urea level, serum phosphate, serum calcium, and parathyroid hormone level, and dialysis-related indicators, including blood pressure fluctuations in dialysis, single-pool Kt/V(spKt/V), and ultrafiltration volume of dialysis were obtained from the ESRD patients. A two-sample t-test was used to examine the group differences in gFCD between ESRD patients and healthy controls after controlling for age, gender and education.

Results

Compared with healthy controls, ESRD patients exhibited a significantly increased gFCD in the salience network, including the bilateral insula, and dorsal anterior cingulated cortex (dACC), and there was no significant correlation between gFCD and the structural mean grey matter volume in patients for every cluster in the brain regions showing significant different gFCD between the two groups. Furthermore, there were significant negative correlations between the degree of connectivity in the right insula and spKt/V.

Conclusion

Our findings revealed abnormal intrinsic dysconnectivity pattern of salience network-related regions in ESRD patients from the whole brain network perspective. The negative correlation between the right insula and spKt/V suggested that increased fractional removal of urea may reduce the pathological activity in the insula.

Cognitive Impairment is Associated with Mortality in Hemodialysis Patients

BACKGROUND

The prevalence of cognitive impairment in hemodialysis patients is notably high. In previous studises performed in the general population, cognitive impairment has been associated with increased mortality.

OBJECTIVE

We evaluated the relationship between global cognitive function tested by a short screening instrument and mortality in hemodialysis patients.

METHODS

Cognitive testing was performed in 242 maintenance hemodialysis patients under standardized conditions at baseline using the Montreal Cognitive Assessment (MoCA).Cognitive impairment was defined as a MoCA test score ≤24 points, as published previously. All-cause mortality was monitored during a median follow-up of 3.54 years. Kaplan-Meier plot and Cox regression model adjusted for known risk factors for mortality in hemodialysis patients were used to examine a possible association between global cognitive function and all-cause mortality.

RESULTS

A MoCA test score ≤24 points resulted in a significant almost 3-fold higher hazard for all-cause mortality (unadjusted hazard ratio [HR]: 2.812; 95% confidence interval [95% CI]: 1.683-4.698; p < 0.001). After adjustment, this association was attenuated but remained significant (adjusted HR: 1.749; 95% CI: 1.007-3.038; p = 0.047).

CONCLUSION

Impairment of global cognitive function measured by a short screening instrument was identified for the first time as an independent predictor of all-cause mortality in hemodialysis patients. Thus, implementing the MoCA test in clinical routine could contribute to a better risk stratification of this patient population.

ER-depletion lowering the 'hypothalamus-uterus-kidney' axis functions by perturbing the renal ERβ/Ptgds signalling pathway

Researchers have long assumed that systematic estrogen fading might contribute to the sustained progression of menopausal degenerate syndromes, although definitive evidence has not been presented. Whether such findings represent a causal contribution or are the result of opportunistic messengers sent from the reproductive system to the brain is also a vital question. We constructed a multiscale network of the ovariectomy (OVX) induced estrogen receptors depletion (ER-depletion) model and integrated targeted proteomic, targeted lipidomic, cytochemical, and histopathological data across three tissues from the ovariectomy rodent model. We found that compared to control rats, OVX rats showed increased renal and uterine prostaglandin D2 synthase (Ptgds) expression and decreased hypothalamic Ptgds expression, abnormal Ptgds metabolites, the degenerate renal function profiles and decreased cognitive ability (learning and memory) in Morris water maze test. Importantly, we observed a regulatory relationship among ER (particularly ERβ), the degree of the pathological phenotype, learning behavior test and the ‘hypothalamus-uterus-kidney (HUK) axis functions. Collectively, this study elucidates that ER depletion promoted HUK aging is mostly attributed to a renal ERβ/Ptgds signalling imbalance.

Caregiving for Older Adults Requiring Hemodialysis: A Comparison Study

This study examined differences in caregiving appraisal between primary family caregivers of disabled older adults receiving hemodialysis (PFCGs-wHD) and disabled older adults not receiving dialysis (PFCGs-woD). A total of 242 PFCGs-wHD and 335 PFCGs-woD were included in the analyses. We used adjustment by propensity score to control for bias by confounding factors. Caregiving appraisal was measured in terms of role strain, emotional exhaustion, and caregiving satisfaction. On the first task, PFCGs-wHD demonstrated significantly worse levels on all three appraisal indicators than did PFCGs-woD. On the second task, only higher emotional exhaustion was significantly mediated by higher role strain in PFCGs-wHD. Further, PFCGs-wHD status directly influenced lower caregiving satisfaction without mediation by higher role strain. Caregiving for disabled older adults receiving HD may be associated with significant challenges for caregivers.

Association between serum homocysteine level and cognitive function in middle-aged type 2 diabetes mellitus patients

Type-2 diabetes mellitus (T2DM) is strongly associated with various complications, including cognitive impairment. Diabetic complication is related with structural and functional changes of brain. Studies investigated that homocysteine as an independent risk factor of several organ complications. This marker might have a role in pathogenesis of cognitive impairment in T2DM patients. We aimed to know the association between serum homocysteine level and cognitive impairment in middle-aged T2DM populations. The study was a cross-sectional study involving 97 T2DM patients aged <60 years old. Cognitive assessment was based on validated Indonesian version of Montreal Cognitive Assessment (MoCA-INA) test. Besides, serum homocysteine level (Hcy) was measured based on standard laboratory assay. Filling out the questionnaire of MoCA-INA was conducted when patients came to take the blood sample. This study used independent t-test, chi-square and multivariate logistic regression model to analyze the data. There were 47 subjects (48.5%) with mild cognitive impairment (MCI). Delayed recall was the most impaired domain (94.8%). There was no significant mean difference of serum Hcy level in MCI and non-MCI group (11.99±3.27 μmol/L vs 12.36±4.07 μmol/L respectively, p = 0.62). Final model of logistic regression showed no association between serum Hcy and cognitive function after adjusting confounding variables (OR: 1.778; 95%CI: 0.69-4.54). Further investigation involving slight elderly T2DM patients with larger sample size should be conducted to confirm this finding.

The gut microbiota-inflammation-brain axis in end-stage renal disease: perspectives from default mode network

The gut-brain axis in end-stage renal disease (ESRD) is attracting more and more attention. However, the mechanism of gut-brain axis based cognitive disorders in ESRD patients remains unclear. The purpose of this study was to investigate the linkages between the gut microbiota, inflammatory cytokines, brain default mode network (DMN) and cognitive function in ESRD patients. Methods: This prospective study enrolled 28 ESRD patients (13 males and 15 females, mean age of 44 ± 14 years) and 19 healthy controls (HCs) (12 males and 7 females, mean age of 44 ± 10 years). All subjects underwent stool microbiota analysis, blood inflammatory cytokines examination, brain MRI scans and cognitive assessments. Resting state functional MRI (rs-fMRI) data were used to construct DMN and graph theory was applied to characterize network topological properties. Two samples t-test was applied for the comparisons between ESRD and HCs. Correlation analysis and mediation analysis were conducted among factors with significant group differences. Results: ESRD patients displayed gut microbiota alterations, increased systemic inflammation and worse cognitive performance compared to HCs (all p < 0.05). Graph analysis revealed disrupted DMN topological organization, aberrant nodal centralities and functional connectivities (FCs) in ESRD patients relative to HCs (all p < 0.05, FDR corrected). Significant correlations were found between gut microbiota, inflammatory cytokines, DMN network measures and cognitive assessments. Mediation analysis found that gut microbiota alteration impaired DMN connectivity by increasing systemic inflammation. Conclusion: The present study first revealed gut microbiota alterations, systemic inflammation, DMN dissociation and cognitive dysfunction in ESRD patients simultaneously and further illuminated their inner relationship.

Chronic kidney disease in the pathogenesis of acute ischemic stroke

Chronic kidney disease has a graded and independent inverse impact on cerebrovascular health. Both thrombotic and hemorrhagic complications are highly prevalent in chronic kidney disease patients. Growing evidence suggests that in chronic kidney disease patients, ischemic strokes are more common than hemorrhagic strokes. Chronic kidney disease is asymptomatic until an advanced stage, but mild to moderate chronic kidney disease incites various pathogenic mechanisms such as inflammation, oxidative stress, neurohormonal imbalance, formation of uremic toxins and vascular calcification which damage the endothelium and blood vessels. Cognitive dysfunction, dementia, transient infarcts, and white matter lesions are widespread in mild to moderate chronic kidney disease patients. Uremic toxins produced after chronic kidney disease can pass through the blood-brain barrier and mediate cognitive dysfunction and neurodegeneration. Furthermore, chronic kidney disease precipitates vascular risk factors that can lead to atherosclerosis, hypertension, atrial fibrillation, and diabetes. Chronic kidney disease also exacerbates stroke pathogenesis, worsens recovery outcomes, and limits the eligibility of stroke patients to receive available stroke therapeutics. This review highlights the mechanisms involved in the advancement of chronic kidney disease and its possible association with stroke.

Depression at Baseline is an Independent Risk Factor for Cognitive Decline in Patients on Peritoneal Dialysis: A Multicenter Prospective Cohort Study

Background

Depression has been recognized as a risk factor for cognitive impairment (CI) from cross-sectional datasets. This multicenter prospective study investigated the association between depression and cognitive decline in peritoneal dialysis (PD) patients.

Methods

This multicenter prospective cohort study included 458 PD patients who were followed up for 2 years. The Modified Mini-Mental State Examination (3MS) was used for assessment of global cognitive function, Trail-Making Tests A and B for executive function, subtests of the Battery for the Assessment of Neuropsychological Status for immediate and delayed memory, visuospatial skill, and language ability. Depression was assessed using Zung's Self-Rating Depression Scale.

Results

During the 2-year follow-up, patients with moderate/severe depression at baseline showed a significant decline in global cognitive function (80.5 ± 15.2 vs 76.6 ± 15.5, p = 0.008), while patients without depression or with mild depression kept a stable global cognitive function. In the meantime, patients without depression showed significant improvements in immediate memory, visuospatial skill, and language ability. However, no significant improvement in these parameters was shown in depression groups. In multivariable linear regression analysis, depression at baseline was a significant predictor of worsening global cognitive function, whether depression was analyzed as a continuous variable (odds ratio [OR] = -0.14, 95% confidence interval [CI] -0.27, -0.01, p = 0.031) or a rank variable (OR = -1.88, 95% CI -3.30, -0.45, p = 0.010). Moreover, higher depression score or more severe depression degradation was significantly associated with decline of immediate memory, delayed memory, and language skill.

Conclusion

Depression was a significant risk factor for worsening of CI in PD patients.

Cognitive assessment in a predominantly Hispanic and Native American population in New Mexico and its association with kidney transplant wait-listing

The association between cognitive function and the likelihood of kidney transplant (KT) wait-listing, especially in minority populations, has not been clearly delineated. We performed a retrospective review of our pre-KT patients, who consist mainly of Hispanics and Native Americans, over a 16-month period. We collected data on baseline demographics and the Montreal Cognitive Assessment (MoCA) score, at the initial KT evaluation. We defined cognitive impairment as MoCA scores of <24. We constructed linear regression models to identify associations between baseline characteristics with MoCA scores and used Cox proportional hazards models to assess associations between MoCA score and KT wait-listing. During the study period, 154 patients completed the MoCA during their initial evaluation. Mean (standard deviation) MoCA scores were 23.9 (4.6), with 58 (38%) participants scoring <24. Advanced age, lower education and being on dialysis were associated with lower MoCA scores. For every one-point increase in MoCA, the likelihood of being wait-listed increased 1.10-fold (95% CI 1.01-1.19, P = .022). Being Native American and having kidney disease due to diabetes or hypertension were associated with longer time to wait-listing. Cognitive impairment was common in our pre-KT patients and was associated with a lower likelihood of KT wait-listing.

Alzheimer's Disease in Systemic Sclerosis Patients: A Nationwide Population-Based Cohort Study

BACKGROUND

Neurological features are often overlooked in systemic sclerosis (SSc) patients and little is known about the link between dementia and SSc.

OBJECTIVES

We sought to investigate whether an association exists between Alzheimer's disease (AD) and SSc, as well as assess the impact of a dual diagnosis on mortality rates, by performing an extensive data analysis on a large subject sample.

METHODS

We utilized the medical database of the Clalit-Health-Services in a case-control study. Patients with SSc were compared with age- and sex-matched controls with regard to the prevalence of AD and its impact on their mortality.

RESULTS

Our study included 2,431 SSc patients and 12,377 age- and sex-matched controls. The mean age of the study population was 63.32±18.06 years and the female to male ratio was 4.5:1. 134 (5.5%) cases had AD as a co-morbidity in comparison with 749 (5.9%) of the controls. The mortality rate was 12.5% among controls and 26.2% among SSc cases. On the Cox multivariate survival analysis, diagnosis of SSc and AD demonstrated significant HRs (2.35 (95% CI 2.05-2.69, p < 0.0001) and 2.19 (95% CI 1.94-2.48, p < 0.0001), respectively). SSc patients with AD had a relative risk of death of 2.35 (95% CI: 1.44-3.83) in comparison with SSc patients without AD.

CONCLUSION

AD is a predictor of death in SSc and therefore preemptive screening may be warranted. Further studies are needed to evaluate whether improvements in the medical regimen for SSc may lead to a reduction in AD development and possibly to increased survival as well.