Intracranial deep white matter lesions (DWLs) are associated with chronic kidney disease (CKD) and cognitive impairment: a 5-year follow-up magnetic resonance imaging (MRI) study

Association of kidney function and brain health: A systematic review and meta-analysis of cohort studies

OBJECTIVE

This study aimed to evaluate the bidirectional association between the kidney dysfunction and the brain health, including structural and functional abnormalities.

DESIGN

Systematic review and meta-analysis with network meta-analysis for outcomes with different estimated glomerular filtration rate (eGFR) ranges.

DATA SOURCES

PubMed, Embase database, Cochrane library and Web of Science (up to Dec. 2021).

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Longitudinal studies that provided evidence of the impact of kidney function estimated from eGFR and urine albumin-to-creatinine ratio (UACR) or chronic kidney disease (CKD) on structural and functional brain abnormalities, and those that provided evidence of the opposite relationship. Studies with study population mean age under 18 years old were excluded.

MAIN OUTCOME MEASURES

Two independent reviewers screened the included studies, extracted the data, and assessed the risk of bias. We performed a random-effects meta-analysis and a network meta-analysis for outcomes with compatible data. We assessed the risk of bias using the Newcastle-Ottawa Quality Assessment Scale criteria (NOS). Subgroup and sensitivity analyses were conducted to explore heterogeneity in the meta-analyses. Inconsistency analyses using the node-splitting method were performed to confirm the results of network meta-analysis.

RESULTS

A total of 53 studies with 3037,357 participants were included in the current systematic review. Among these, 16 provided evidence of structural brain abnormalities, and 38 provided evidence of cognitive impairment and dementia. Analysis of evidence of categorical kidney function showed a positive association between kidney dysfunction and cerebral small vessel disease (cSVD) (relative risk (RR) 1.77, 95% confidence interval (CI) 1.40-2.24, I² = 0.0%), but such results were not found in the analyses of evidence where the kidney function was measured as a continuous variable. Meanwhile, analysis of 28 prior longitudinal studies with 194 compatible sets of data showed that the worse kidney function as categorical variables was related to a greater risk of global brain cognitive disorder (RR 1.28, 95% CI 1.20-1.36, I² = 82.5%).

CONCLUSIONS

In this systematic review and meta-analysis, we found a positive association between CKD and functional brain disorders. However, the relationship between the kidney dysfunction and structural abnormalities in the brain remains controversial. As for the opposite relationship, structural brain abnormalities, especially cerebral microbleeds and silent infarction, but not functional brain abnormalities, are associated with worse renal function. In addition, a higher UACR, but not a lower eGFR, was associated with a higher risk of Alzheimer's disease and vascular dementia.

Association Between Cerebral Microbleeds and Circulating Levels of Mid-Regional Pro-Adrenomedullin

Background: Mid-regional pro-adrenomedullin (MR-proADM) is a novel biomarker for cognitive decline based on its association with cerebral small vessel disease (SVD). Cerebral microbleeds (MBs) are characteristic of SVD; however, a direct association between MR-proADM and MBs has not been explored. Objective: We aimed to examine whether circulating levels of MR-proADM are associated with the identification of MBs by brain magnetic resonance imaging (MRI) and whether this association could be linked with cognitive impairment. Methods: In total, 214 participants (mean age: 75.9 years) without history of cerebral infarction or dementia were prospectively enrolled. All participants underwent brain MRI, higher cognitive function testing, blood biochemistry evaluation, lifestyle examination, and blood MR-proADM measurement using a time-resolved amplified cryptate emission technology assay. For between-group comparisons, the participants were divided into two groups according to whether their levels of MR-proADM were normal (<  0.65 nmol/L) or high (≥0.65 nmol/L). Results: The mean MR-proADM level was 0.515±0.127 nmol/L. There were significant between-group differences in age, hypertension, and HbA1c levels (p <  0.05). In the high MR-proADM group, the MR-proADM level was associated with the identification of MBs on brain MR images and indications of mild cognitive impairment (MCI). In participants with ≥3 MBs and MCI, high MR-proADM levels remained a risk factor after multivariate adjustment (OR: 2.94; p <  0.05). Conclusion: High levels of MR-proADM may be a surrogate marker for the early detection of cognitive decline associated with the formation of cerebral MBs. This marker would be valuable during routine clinical examinations of geriatric patients.

Association Between White Matter Hyperintensities and Chronic Kidney Disease: A Systematic Review and Meta-Analysis

Objectives

Previous studies of the associations between white matter hyperintensities (WMH) and chronic kidney disease (CKD) were still conflicting; therefore, our study aimed to conduct a systematic review of all of the available research on this topic and a meta-analysis of the association between WMH and CKD among observational studies.

Setting and Design

Systematic review and meta-analysis.

Outcome Measures

Severity of WMH.

Methods and Participants

All relevant studies in public databases were examined until 15 November 2020. Two independent reviewers assessed all the included studies using the Cross-Sectional/Prevalence Study Quality (CSSQ) scale, and then literature review and meta-analyses were undertaken.

Results

We pooled the odds ratio (OR) for the presence of WMH, periventricular hyperintensities (PVH), and deep subcortical white matter hyperintensities (DWMH) of patients with CKD vs. non-CKD patients by subgroup analysis, and the results obtained were WMH OR 2.07, 95% CI [1.58, 2.70], PVH OR 2.41, 95% CI [1.90, 3.05], and DWMH OR 2.11, 95% CI [1.60, 2.80], respectively. The main outcome showed that patients with CKD were more likely to have WMH in the brain compared to the normal controls. Another meta-analysis showed a statistically significant decline in renal function in patients with moderate to severe WMH compared with those with no to mild WMH.

Conclusions

The findings indicated that patients with CKD were more likely to experience WMH than demographically matched controls. On the other hand, patients with moderate to severe WMH in the brain had poor renal function more frequently than those with no to mild WMH.

Impacts of Kidney Dysfunction and Cerebral Cortical Thinning on Cognitive Change in Elderly Population

BACKGROUND

Cerebral cortical thickness is a neuroimaging biomarker to predict cognitive decline, and kidney dysfunction (KD) is associated with cortical thinning.

OBJECTIVE

This study aimed to investigate the effects of KD and cortical thinning on cognitive change in a prospective cohort study.

METHODS

A total of 244 non-demented participants were recruited from elderly health checkup program and received cognitive exams including Montreal Cognitive Assessment (MoCA) and different cognitive domains at baseline and three biannual follow-ups afterwards. KD was defined as having either glomerular filtration rate <60 ml/min/1.73 m2 or proteinuria. Cortical thickness of global, lobar, and Alzheimer's disease (AD) signature area were derived from magnetic resonance imaging at baseline, and cortical thinning was defined as the lowest tertile of cortical thickness. Generalized linear mixed models were applied to evaluate the effects of KD and cortical thinning on cognitive changes.

RESULTS

KD was significantly associated with the decline in attention function (β= -0.29). Thinning of global (β= -0.06), AD signature area (β= -0.06), temporal (β= -0.06), and parietal lobes (β= -0.06) predicted poor verbal fluency over time, while temporal lobe thinning also predicted poor MoCA score (β= -0.19). KD modified the relationship between thinning of global, frontal, and limbic, and change of logical memory function (pinteraction < 0.05). When considering jointly, participants with both KD and cortical thinning had greatest decline in attention function compared with those without KD or cortical thinning (β= -0.51, ptrend = 0.008).

CONCLUSIONS

KD and cortical thinning have joint effect on cognitive decline, especially the attention function. Reverse associations may exist between cortical thinning and memory function in participants with KD, though the results should be interpreted cautiously as an exploratory analysis.

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.

Altered brain structural and cognitive impairment in end-stage renal disease patients with secondary hyperparathyroidism

BACKGROUND

Cognitive impairment has received attention as an important problem in patients with end-stage renal disease, although end-stage renal disease patients with secondary hyperparathyroidism have not been studied.

PURPOSE

To assess the pattern of brain volume changes in end-stage renal disease patients with secondary hyperparathyroidism by using voxel-based morphometry and correlating these measures with clinical markers and the Montreal Cognitive Assessment scores.

MATERIAL AND METHODS

Fifty end-stage renal disease patients with no anatomical abnormalities in conventional MRI (25 patients with secondary hyperparathyroidism, 14 men, mean age 42.20 ± 7.53 years; 25 patients without secondary hyperparathyroidism, 15 men, mean age 41.96 ± 6.17 years) were selected in this study. All patients underwent laboratory tests, neuropsychological tests, and MRI. Voxel-based morphometry analysis was performed to detect regional gray matter volume differences between the two groups. The relationships between abnormal gray matter volume and clinical markers and Montreal Cognitive Assessment scores were investigated.

RESULTS

Voxel-based morphometry revealed increased gray matter volume in end-stage renal disease patients with secondary hyperparathyroidism in the bilateral caudate and bilateral thalamus compared with non- secondary hyperparathyroidism end-stage renal disease patients (P < 0.05, FWE corrected). Regarding the laboratory and neuropsychological tests, we found significant correlations between volume in these brain regions and intact parathyroid hormone levels and negative correlations with the Montreal Cognitive Assessment scores. There were no significant associations between brain volume changes and other clinical data (disease duration, urea, creatinine, and uric acid levels).

CONCLUSION

Our results showed significantly increased gray matter volume in end-stage renal disease patients with secondary hyperparathyroidism, which was associated with intact parathyroid hormone levels and cognitive impairment. Serum intact parathyroid hormone levels may be a risk factor for cognitive impairment in end-stage renal disease patients with secondary hyperparathyroidism.

Association of brain white matter lesions and atrophy with cognitive function in chronic kidney disease

OBJECTIVES

Cognitive impairment is common in patients with chronic kidney disease (CKD), possibly leading to poor outcomes. However, the correlation between brain structural abnormalities and cognitive impairment remains unclear. The aim of this study was to investigate the impairment of specific cognitive domains and their association with brain structural abnormalities.

METHODS

Patients with CKD of at least stage 3 who were not on hemodialysis were enrolled. All participants underwent comprehensive neuropsychological testing in five cognitive domains. Ventricular atrophy, sulcal atrophy, medial temporal atrophy, and white matter changes were assessed using brain magnetic resonance imaging according to standard protocols.

RESULTS

Eighty-seven patients and 50 controls were enrolled. Patients with CKD exhibited decreased cognitive function relative to controls. Compared with patients with stage 3 CKD, those with advanced stage (stages 4 or 5) had poorer cognitive performance, more pronounced white matter hyperintensity (WMH) and more severe ventricular atrophy. Among CKD patients, executive function (β = -.23, P = .043) and attention (β = -.29, P = .004) were associated with WMH in controlled analyses. However, no cognitive impairment was associated with ventricular atrophy.

CONCLUSION

Patients with CKD exhibited cognitive impairment and brain structural abnormalities including WMH and general brain atrophy. Impairment of attention and executive dysfunction were associated with WMH.

The Role of Brain Magnetic Resonance Imaging (MRI) as an Early Detector of Cognitive Impairment

Background:

Along with the increase of the health and prosperity level will affect the life expectancy in Indonesia, there has also been an increase in degenerative disease cases. One of the problems arises is cognitive impairment. The mild version of this impairment is often associated with the increase risk that will eventually lead to dementia. Therefore, early detection of this impairment is necessary.

Objective:

This study is aimed at proving the correlation between Fazekas scale on brain MRI and MoCA-Ina score in defining the degree of cognitive impairment.

Methods:

This study employed observational analytic design and cross sectional study for its data collection method. The Fazekas scale on brain MRI of 32 patients was read by 3 radiologist, while the MoCA-Ina scoring was done by a competent neurologist. Both tests were done double blindly. Later on, the correlation between Fazekas scale and MoCA-Ina score would be assessed using Spearman Correlation.

Results:

Statistical calculation conducted using Spearman Correlation reveals that the coefficient is -0.519 with significant score (P) 0.002, which is smaller than α: 0.05. Therefore, it can be concluded that there is a strong negative correlation between Fazekas scale and MoCA-Ina score.

Conclusion:

Fazekas scale evaluation on brain MRI is necessary to be performed as it helps predicting the decline of one's cognitive function, so that an early therapy can be acted upon to prevent dementia in the future.

Association between α-Klotho and Deep White Matter Lesions in the Brain: A Pilot Case Control Study Using Brain MRI

BACKGROUND

The anti-aging protein, α-Klotho, may be involved in cognitive decline and has potential as a surrogate marker that reflects dementia. However, the role of α-Klotho in the brain has not been sufficiently investigated.

OBJECTIVE

Here, we investigated the association between α-Klotho and cognitive decline that is associated with cerebral deep white matter lesions (DWMLs).

METHODS

Two hundred-eighty participants (187 males and 93 females, mean age: 70.8 years old) were evaluated for DWMLs, and the Fazekas scale (Grade) was assessed following brain magnetic resonance imaging. A questionnaire concerning lifestyle and neuropsychological tests was administered, and their associations with the blood α-Klotho level were retrospectively investigated.

RESULTS

The α-Klotho level was 685.1 pg/mL in Grade 0 (68 subjects), 634.1 in G1 (134), 596.0 in G2 (62), and 571.6 in G3 (16), showing that the level significantly decreased with advanced grades. Significant correlations were noted between the α-Klotho level and higher brain function tests including the Mini-Mental State Examination and word fluency tests (p < 0.05). When a 90th percentile value of the level in the G0 group (400 pg/mL) or lower was defined as a low α-Klotho level, the odds ratio of the high-grade G3 group was 2.9 (95% confidence interval: 1.4-7.8) (after correction for age, sex, hypertension, and chronic kidney disease), which was significant.

CONCLUSION

A reduced blood α-Klotho level was correlated with grading of cerebral DWMLs and was accompanied by cognitive decline as an independent risk factor. The α-Klotho level may serve as a useful clinical index of vascular cognitive impairment.

The assessment of cognitive function in older adult patients with chronic kidney disease: an integrative review

INTRODUCTION

Chronic kidney disease (CKD) is a common chronic condition in older adults that is associated with cognitive decline. However, the exact prevalence of cognitive impairment in older adults with CKD is unclear likely due to the variety of methods utilized to assess cognitive function. The purpose of this integrative review is to determine how cognitive function is most frequently assessed in older adult patients with CKD.

METHODS

Five electronic databases were searched to explore relevant literature related to cognitive function assessment in older adult patients with CKD. Inclusion and exclusion criteria were created to focus the search to the assessment of cognitive function with standardized cognitive tests in older adults with CKD, not on renal replacement therapy.

RESULTS

Through the search methods, 36 articles were found that fulfilled the purpose of the review. There were 36 different types of cognitive tests utilized in the included articles, with each study utilizing between one and 12 tests. The most commonly utilized cognitive test was the Mini Mental State Exam (MMSE), followed by tests of digit symbol substitution and verbal fluency. The most commonly assessed aspect of cognitive function was global cognition.

DISCUSSION

The assessment of cognitive function in older adults with CKD with standardized tests is completed in various ways. Unfortunately, the common methods of assessment of cognitive function may not be fully examining the domains of impairment commonly found in older adults with CKD. Further research is needed to identify the ideal cognitive test to best assess older adults with CKD for cognitive impairment.

Malnutrition-inflammation is a risk factor for cerebral small vessel diseases and cognitive decline in peritoneal dialysis patients: a cross-sectional observational study

Background

Chronic kidney disease patients have an increased prevalence of subclinical cerebrovascular diseases. Dialysis patients have severe vascular diseases burden. The cerebral small vessel diseases (CSVD) are difficult to find by clinical assessment. The evaluation of CVSD needs MRI. Cognitive impairment is a consequence of CVSD which is diagnosed by cognitive testing. These limited the study of CVSD and cognitive function in dialysis patients. Peritoneal dialysis (PD) patients are minority of dialysis population. We know even fewer about the CVSD in this special population.

Methods

In this cross-sectional study, we enrolled 72 PD patients who received care at the Peking Union Medical College hospital peritoneal dialysis center. CSVD were assessed by brain MR images. Cognitive function was evaluated with the Chinese version of the MMSE and MoCA.

Results

In our PD patients, the brain MRI showed the prevalence different signs of CSVD were: lacunar infarcts 38.9%, microbleeds 36.1%, abnormal brain white matter hyperintensities (WMHs) 48.6%, and intracerebral hemorrhage 4.2%. 25% and 86.8%of our patients could be diagnosed as cognitive impairment, according to the MMSE and MoCA test, respectively. nPCR was lower in patients with a lacunar infarct or intracerebral hemorrhage, and relative to the MMSA/MoCA score; hsCRP was higher in patients with lacunar infarct or abnormal WMHs and negative relative to the MMSA/MoCA score. In logistic regression analyses, nPCR was an independent risk factor for lacunar infarcts and impaired cognitive function. The presence of lacunar infarct was an independent risk factor for cognitive function decline.

Conclusion

We demonstrated a high prevalence of CSVD and cognitive impairment in our PD patients. Lacunar infarct was the main kind of CVSD responsible for PD patients cognitive function decline. Our novel observation also revealed an association between malnutrition-inflammation and CSVD.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0777-1) contains supplementary material, which is available to authorized users.

Associations of Early Kidney Disease With Brain Magnetic Resonance Imaging and Cognitive Function in African Americans With Type 2 Diabetes Mellitus

BACKGROUND

Relationships between early kidney disease, neurocognitive function, and brain anatomy are poorly defined in African Americans with type 2 diabetes mellitus (T2DM).

STUDY DESIGN

Cross-sectional associations were assessed between cerebral anatomy and cognitive performance with estimated glomerular filtration rate (eGFR) and urine albumin-creatinine ratio (UACR) in African Americans with T2DM.

SETTING & PARTICIPANTS

African Americans with cognitive testing and cerebral magnetic resonance imaging (MRI) in the African American-Diabetes Heart Study Memory in Diabetes (AA-DHS MIND; n=512; 480 with MRI) and Action to Control Cardiovascular Risk in Diabetes (ACCORD) MIND (n=484; 104 with MRI) studies.

PREDICTORS

eGFR (CKD-EPI creatinine equation), spot UACR.

MEASUREMENTS

MRI-based cerebral white matter volume (WMV), gray matter volume (GMV), and white matter lesion volume; cognitive performance (Mini-Mental State Examination, Digit Symbol Coding, Stroop Test, and Rey Auditory Verbal Learning Test). Multivariable models adjusted for age, sex, body mass index, scanner, intracranial volume, education, diabetes duration, hemoglobin A1c concentration, low-density lipoprotein cholesterol concentration, smoking, hypertension, and cardiovascular disease were used to test for associations between kidney phenotypes and the brain in each study; a meta-analysis was performed.

RESULTS

Mean participant age was 60.1±7.9 (SD) years; diabetes duration, 12.1±7.7 years; hemoglobin A1c concentration, 8.3%±1.7%; eGFR, 88.7±21.6mL/min/1.73m2; and UACR, 119.2±336.4mg/g. In the fully adjusted meta-analysis, higher GMV associated with lower UACR (P<0.05), with a trend toward association with higher eGFR. Higher white matter lesion volume was associated with higher UACR (P<0.05) and lower eGFR (P<0.001). WMV was not associated with either kidney parameter. Higher UACR was associated with lower Digit Symbol Coding performance (P<0.001) and a trend toward association with higher Stroop interference; eGFR was not associated with cognitive tests.

LIMITATIONS

Cross-sectional; single UACR measurement.

CONCLUSIONS

In African Americans with T2DM, mildly high UACR and mildly low eGFR were associated with smaller GMV and increased white matter lesion volume. UACR was associated with poorer processing speed and working memory.

The Cognitive decline in Older Patients with End stage renal disease (COPE) study - rationale and design

BACKGROUND

Older patients with end stage renal disease (ESRD) are at increased risk for cognitive decline, but detailed studies of the magnitude of cognitive decline on dialysis or comprehensive conservative management (CCM) are lacking and the underlying pathophysiological mechanisms have poorly been studied.

OBJECTIVES

To describe the rationale and design of the COPE study. Study objectives are as follows. Firstly, to examine the severity of cognitive impairment in older patients reaching ESRD before dialysis and the rate of decline after dialysis or CCM initiation. Secondly, to study the association of blood biomarkers for microvascular damage and MRI derived measurements of small vessel disease with the rate of cognitive decline. Thirdly, to examine to what extent cardiac function is related to brain structure and perfusion in patients reaching ESRD. Finally, to study the association of cognitive and functional capacity with quality of life in pre-dialysis patients, as well as after dialysis or CCM initiation.

STUDY DESIGN AND METHODS

The COPE study is a prospective, multicenter cohort study in the Netherlands, including prevalent and incident pre-dialysis patients ≥65 years old with eGFR ≤20 ml/min/1.73 m², awaiting either dialysis or CCM initiation. At baseline extensive data is collected including a comprehensive geriatric assessment and laboratory tests. Brain and cardiac MRI for analysis of structural and functional abnormalities are performed at baseline and repeated following therapy change. All other measurements are repeated annually during four years of follow up, including an extra evaluation six months after initiation of dialysis.

CONCLUSIONS

Knowledge of the magnitude of cognitive decline and its underlying pathophysiological mechanism, as well as its impact on functionality and quality of life can eventually help to postulate an algorithm for well balanced decision making in treatment strategies in older patients reaching ESRD.

CLINICAL TRIAL REGISTRATION

The COPE study is registered on www.ccmo.nl (number: NL46389.058.13).

Validation of the R2CHADS2 and CHADS2 Scores for Predicting Post-stroke Cognitive Impairment

Objective Post-stroke cognitive impairment often afflicts stroke survivors and is a major obstacle both for cognitive and physical rehabilitation. Stroke risk scores ["Congestive heart failure, Hypertension, Age ≥75 years, Diabetes mellitus, Stroke" (CHADS₂) and "CHADS₂ + creatinine clearance <60 mL/min" (R₂CHADS₂)] are used to assess the future risk of cardioembolic stroke in patients with atrial fibrillation (AF). However, congestive heart failure, hypertension, aging, diabetes mellitus, stroke, and renal dysfunction are also risk factors for cognitive impairment. Methods Sixty-two patients with nonvalvular AF-induced cardioembolic stroke underwent cognitive testing, including the Japanese version of the Montreal Cognitive Assessment (MoCA-J), Mini-Mental State Examination (MMSE), and Apathy Scale. The correlations between the MoCA-J/MMSE/Apathy Scale scores and stroke risk scores were examined. Results The average CHADS₂ and R₂CHADS₂ scores were 4.1±1.0 and 5.6±1.6, respectively. The average MoCA-J, MMSE, and Apathy Scale scores were 17.4±6.2, 22.0±5.3, and 20.0±8.9, respectively. The CHADS₂ and R₂CHADS₂ scores were negatively correlated with the MoCA-J/MMSE and positively correlated with the Apathy Scale. The R₂CHADS₂ score was more sensitive to poststroke cognitive impairment than the CHADS₂ score. This correlation was stronger for MoCA-J than for MMSE, as the MMSE scores were skewed toward the higher end of the range. The results for individual MoCA-J and MMSE subtests indicated that the visuoexecutive, calculation, abstraction, and remote recall functions were significantly decreased after cardioembolic stroke. Conclusion These results suggest that the R₂CHADS₂ and CHADS₂ scores are useful for predicting post-stroke cognitive impairment.

Chronic kidney disease-related physical frailty and cognitive impairment: a systemic review

AIM

The objective of this review was to assess chronic kidney disease-related frailty and cognitive impairment, as well as their probable causes, mechanisms and the interventions.

METHODS

Studies from 1990 to 2015 were reviewed to evaluate the relationship between chronic kidney disease and physical frailty and cognitive impairment. Of the 1694 studies from the initial search, longitudinal studies (n = 22) with the keywords "Cognitive and CKD" and longitudinal or cross-sectional studies (n = 5) with the keywords "Frailty and CKD" were included in final analysis.

RESULTS

By pooling current research, we show clear evidence for a relationship between chronic kidney disease and frailty and cognitive impairment in major studies. Vascular disease is likely an important mediator, particularly for cognitive impairment. However, non-vascular factors also play an important role. Many of the other mechanisms that contribute to impaired cognitive function and increased frailty in CKD remain to be elucidated. In limited studies, medication therapy did not obtain the ideal effect. There are limited data on treatment strategies, but addressing the vascular disease risk factors earlier in life might decrease the subsequent burden of frailty and cognitive impairment in this population. Multidimensional interventions, which address both microvascular health and other factors, may have substantial benefits for both the cognitive impairments and physical frailty in this vulnerable population.

CONCLUSIONS

Chronic kidney disease is a potential cause of frailty and cognitive impairment. Vascular and non-vascular factors are the possible causes. The mechanism of chronic kidney disease-induced physical frailty and cognitive impairment suggests that multidimensional interventions may be effective therapeutic strategies in the early stage of chronic kidney disease. Geriatr Gerontol Int 2017; 17: 529-544.

Proceedings From the Symposium on Kidney Disease in Older People: Royal Society of Medicine, London, January 19, 2017

People are living longer. On the whole, they have healthier lives and many of the problems previously seen at a younger age now appear in their later years. Kidneys, like other organs, age, and kidney disease in the aged is a prime example. In the United Kingdom, as in other developed countries, the prevalence of end stage kidney disease is highest in the 70- to 79-year-old age group. There are many older people who require renal replacement and are now considered for dialysis. While older patients with end-stage renal disease invariably aspire for a better quality of life, this needs a specialized approach and management. In January 2017, the Royal Society of Medicine held a seminar in London on "Kidney Disease in Older People" with presentations from a multidisciplinary body of experts speaking on various aspects of kidney problems in this age group and its management. The objectives were to increase awareness and improve the understanding of nephrology in the context of geriatric medicine but also geriatrics in its interface with nephrology, especially in the area of chronic kidney disease.

Oral Cnm-positive Streptococcus Mutans Expressing Collagen Binding Activity is a Risk Factor for Cerebral Microbleeds and Cognitive Impairment

Cerebral microbleeds (CMBs) are an important risk factor for stroke and dementia. We have shown that the collagen binding surface Cnm protein expressed on cnm-positive Streptococcus mutans is involved in the development of CMBs. However, whether the collagen binding activity of cnm-positive S. mutans is related to the nature of the CMBs or to cognitive impairment is unclear. Two-hundred seventy nine community residents (70.0 years) were examined for the presence or absence of cnm-positive S. mutans in the saliva by PCR and collagen binding activity, CMBs, and cognitive function were evaluated. Cnm-positive S. mutans was detected more often among subjects with CMBs (p < 0.01) than those without. The risk of CMBs was significantly higher (odds ratio = 14.3) in the group with S. mutans expressing collagen binding activity, as compared to the group without that finding. Deep CMBs were more frequent (67%) and cognitive function was lower among subjects with cnm-positive S. mutans expressing collagen binding activity. This work supports the role of oral health in stroke and dementia and proposes a molecular mechanism for the interaction.

Serum albumin to globulin ratio is related to cognitive decline via reflection of homeostasis: a nested case-control study

BACKGROUND

Recent research suggests that several pathogenetic factors, including aging, genetics, inflammation, dyslipidemia, diabetes, and infectious diseases, influence cognitive decline (CD) risk. However, no definitive candidate causes have been identified. The present study evaluated whether certain serum parameters predict CD.

METHODS

A total of 151 participants were assessed for CD using the Mini-Mental State Examination (MMSE), and 34 participants were identified as showing CD.

RESULTS

Among CD predictive risk factors, Helicobacter pylori seropositivity was significantly predictive of CD risk, more so than classical risk factors, including white matter lesions and arterial stiffness [adjusted odds ratio (OR) = 4.786, 95% confidence interval (CI) = 1.710-13.39]. A multivariate analysis indicated that the albumin to globulin (A/G) ratio was the only factor that significantly lowered CD risk (OR = 0.092, 95% CI = 0.010-0.887). A/G ratio also was positively correlated with MMSE scores and negatively correlated with disruption of homeostatic factors (i.e., non-high-density lipoprotein, hemoglobin A1c, and high-sensitive C-reactive protein).

CONCLUSIONS

The current study results suggest that the A/G ratio is related to cognitive decline and may reflect homeostatic alterations.

Enzyme replacement therapy stabilized white matter lesion progression in Fabry disease

BACKGROUND

The central nervous system manifestations in Fabry disease (FD) include progressive white matter lesions (WMLs) and stroke. Due to progressive microvascular involvement, men and women with FD over 35 years of age develop WMLs. Moreover, the prevalence of stroke has been estimated to be 12 times higher in FD compared with the general population. Enzyme replacement therapy (ERT) is available and has shown beneficial effects on renal, cardiac, and peripheral nerve function in FD, but the ERT effect on the progression of WMLs, or the reduction in cerebrovascular events, remains unknown.

METHODS

The WML burden and the effect of agalsidase beta 1 mg/kg biweekly on WML progression were assessed longitudinally in a Phase 4 agalsidase-beta placebo-controlled analysis of untreated and treated FD patients with mild-to-moderate renal involvement (serum creatinine measurements of ≥1.2 mg/dl and <3.0 mg/dl). The primary end point was the difference in the number of patients with increased WML burden between the agalsidase beta and placebo groups at the end of treatment. The diameters of the WMLs were determined manually using axial flow-attenuated-inversion-recovery-weighted magnetic resonance imaging (MRI) scans taken at baseline and follow-up.

RESULTS

MRI scans from 41 FD patients (mean age 43.9, age range 20-68, 3 females; n=25 on ERT, n=16 on placebo) were analyzed. WML burden was present in 63% of patients at baseline, increased over a mean of 27 months (range 12-33 months) follow-up, and correlated with left ventricular hypertrophy (LVPW). Patients with previous or recent strokes (n=11, 39-68 years) showed an increase in the number of WMLs (p=0.005). A greater proportion of younger patients (≤50 years) on ERT (n=18) had stable WML burden compared with younger patients in the placebo group (n=13): 44% (8 of 18) versus 31% (4 of 13), p=0.014. The number needed to treat was 8.

CONCLUSIONS

This FD patient cohort, with mild-to-moderate renal involvement, had a significant WML burden and high inter-individual variability associated with the degree of LVPW but not the degree of kidney dysfunction. These advanced patients with increased LVPW and stroke evidence may have had a higher cerebrovascular risk. The WML burden in patients on ERT was more likely to remain stable, compared with patients on placebo. Thus, ERT may reduce the progression of vascular disease, even in advanced FD patients, suggesting that early treatment may stabilize WML progression and stroke risk.

Neurological complications in chronic kidney disease patients

Chronic kidney disease (CKD) is associated with a high prevalence of cerebrovascular disorders such as stroke, white matter diseases, intracerebral microbleeds and cognitive impairment. This situation has been observed not only in end-stage renal disease patients but also in patients with mild or moderate CKD. The occurrence of cerebrovascular disorders may be linked to the presence of traditional and non-traditional cardiovascular risk factors in CKD. Here, we review current knowledge on the epidemiological aspects of CKD-associated neurological and cognitive disorders and discuss putative causes and potential treatment. CKD is associated with traditional (hypertension, hypercholesterolaemia, diabetes etc.) and non-traditional cardiovascular risk factors such as elevated levels of oxidative stress, chronic inflammation, endothelial dysfunction, vascular calcification, anaemia and uraemic toxins. Clinical and animal studies indicate that these factors may modify the incidence and/or outcomes of stroke and are associated with white matter diseases and cognitive impairment. However, direct evidence in CKD patients is still lacking. A better understanding of the factors responsible for the elevated prevalence of cerebrovascular diseases in CKD patients may facilitate the development of novel treatments. Very few clinical trials have actually been performed in CKD patients, and the impact of certain treatments is subject to debate. Treatments that lower LDL cholesterol or blood pressure may reduce the incidence of cerebrovascular diseases in CKD patients, whereas treatment with erythropoiesis-stimulating agents may be associated with an increased risk of stroke but a decreased risk of cognitive disorders. The impact of therapeutic approaches that reduce levels of uraemic toxins has yet to be evaluated.

Relationship between Cnm-positive Streptococcus mutans and cerebral microbleeds in humans

OBJECTIVE

Cerebral hemorrhage has been shown to occur in animals experimentally infected with Streptococcus mutans carrying the collagen-binding Cnm gene. However, the relationship between cerebral microbleeds and oral hygiene, with a focus on Cnm gene-positive S. mutans infection, remains unclear.

MATERIAL AND METHODS

One hundred and thirty-nine subjects participated. The presence or absence of Cnm-positive S. mutans and its collagen-binding activity were investigated using saliva samples, and relationship with cerebral microbleeds detected on MRI investigated, including clinical information and oral parameters.

RESULTS

Fifty-one subjects were identified as Cnm-positive S. mutans carriers (36.7%), with cerebral microbleeds being detected in 43 (30.9%). A significantly larger number of subjects carried Cnm-positive S. mutans in the cerebral microbleeds (+) group. S. mutans with Cnm collagen-binding ability was detected in 39 (28.1%) of all subjects, and the adjusted odds ratio for cerebral microbleeds in the Cnm-positive group was 14.4. Regarding the presence of cerebral microbleeds, no significant differences were noted in the number of remaining teeth, dental caries, or in classic arteriosclerosis risk factors.

CONCLUSIONS

The occurrence of cerebral microbleeds was higher in subjects carrying Cnm-positive S. mutans, indicating that the presence of Cnm-positive S. mutans increases cerebral microbleeds, and is an independent risk for the development of cerebrovascular disorders.

Abnormal Intrinsic Brain Activity Patterns in Patients with End-Stage Renal Disease Undergoing Peritoneal Dialysis: A Resting-State Functional MR Imaging Study

PURPOSE

To analyze the spontaneous brain activity patterns in patients with end-stage renal disease (ESRD) undergoing peritoneal dialysis (PD) by using resting-state functional magnetic resonance (MR) imaging with an amplitude of low-frequency fluctuations (ALFF) algorithm.

MATERIALS AND METHODS

This study received institutional review board approval, and all subjects gave informed consent. Forty-four patients with ESRD, 24 of whom were undergoing PD (PD group; eight women; mean age, 34 years ± 8) and 20 who were not undergoing PD or hemodialysis (nondialysis group; six women; mean age, 37 years ± 9) and 24 healthy control subjects (eight women; mean age, 32 years ± 9 years) were included. All subjects underwent neuropsychologic tests, and patients with ESRD underwent laboratory testing. ALFF values were compared among the three groups. The relationship between ALFF values and clinical markers was investigated by using multiple regression analysis.

RESULTS

Patients in both the PD and nondialysis groups showed lower ALFF values in default mode network regions than did healthy control subjects (P < .01, false discovery rate corrected). Patients in the PD group showed lower ALFF values than did those in the nondialysis group in the left superior parietal lobe (1.51 ± 0.21 vs 2.01 ± 0.40), left inferior parietal lobe (0.99 ± 0.16 vs 1.13 ± 0.22) and left precuneus (1.45 ± 0.39 vs 1.77 ± 0.41) (P < .01, corrected with simulation software). In patients in the PD group, neuropsychologic test scores correlated with ALFF values of the middle temporal gyrus and the parietal and occipital lobe, serum urea and creatinine levels negatively correlated with ALFF in some default mode network regions, and hemoglobin positively correlated with ALFF in the bilateral precuneus, precentral, and supplementary motor areas (P < .01 corrected).

CONCLUSION

Patients with ESRD who were undergoing PD showed more severe spontaneous brain activity abnormalities that correlate with cognitive impairments than did patients who were not undergoing dialysis. Elevated serum urea, creatinine, and lowered hemoglobin levels affect spontaneous brain activity in patients with ESRD.

The association between kidney function and cognitive decline in community-dwelling, elderly Japanese people

OBJECTIVES

The aim of this study was to evaluate the relationship between chronic kidney disease (CKD) and cognitive decline in community-dwelling older adults without dementia.

DESIGN

Cross-sectional.

SETTING

Obu Study of Health Promotion for the Elderly in Japan.

PARTICIPANTS

The participants were 4686 residents (community-dwelling older adults without dementia) who completed baseline assessments.

MEASUREMENTS

The estimated glomerular filtration rate (eGFR, mL/min/1.73 m(2)) was determined according to the creatinine level, and participants were classified into three mutually exclusive categories: normal (≥60.0 mL/min/1.73 m(2)), mild CKD (45.0-59.9 mL/min/1.73 m(2)), or moderate to severe CKD (<45.0 mL/min/1.73 m(2)). Cognitive function was assessed using the National Center for Geriatrics and Gerontology-Functional Assessment Tool. Multivariate logistic regression was used to examine the relationships between eGFR and cognitive decline.

RESULTS

After multivariate adjustment, participants with lower eGFR had lower cognitive function scores on most domains (P < .05). In particular, participants with advanced CKD (eGFR <45 mL/min/1.73 m(2)) were more likely to have significant cognitive decline on the Trail Making Test part A (odds ratio = 2.347, 95% confidence interval = 1.525-3.614) and the Symbol Digit Substitution Task (odds ratio = 2.308, 95% confidence interval = 1.486-3.585) than those with normal and mild CKD.

CONCLUSIONS

A lower level of kidney function was associated with lower cognitive performance in attention and processing speed. These results suggest that eGFR might be an effective method to screen for cognitive decline in community-dwelling older adults.

Cognitive and kidney function: results from a British birth cohort reaching retirement age

BACKGROUND

Previous studies have found associations between cognitive function and chronic kidney disease. We aimed to explore possible explanations for this association in the Medical Research Council National Survey of Health and Development, a prospective birth cohort representative of the general British population.

METHODS

Cognitive function at age 60-64 years was quantified using five measures (verbal memory, letter search speed and accuracy, simple and choice reaction times) and glomerular filtration rate (eGFR) at the same age was estimated using cystatin C. The cross-sectional association between cognitive function and eGFR was adjusted for background confounding factors (socioeconomic position, educational attainment), prior cognition, and potential explanations for any remaining association (smoking, diabetes, hypertension, inflammation, obesity).

RESULTS

Data on all the analysis variables were available for 1306-1320 study members (depending on cognitive measure). Verbal memory and simple and choice reaction times were strongly associated with eGFR. For example, the lowest quartile of verbal memory corresponded to a 4.1 (95% confidence interval 2.0, 6.2) ml/min/1.73 m(2) lower eGFR relative to the highest quartile. Some of this association was explained by confounding due to socioeconomic factors, but very little of it by prior cognition. Smoking, diabetes, hypertension, inflammation and obesity explained some but not all of the remaining association.

CONCLUSIONS

These analyses support the notion of a shared pathophysiology of impaired cognitive and kidney function at older age, which precedes clinical disease. The implications of these findings for clinical care and research are important and under-recognised, though further confirmatory studies are required.

TGF-beta1 is associated with the progression of intracranial deep white matter lesions: a pilot study with 5 years of magnetic resonance imaging follow-up

OBJECTIVES

Elevated expression of transforming growth factor (TGF)-beta1 has been reported in hereditary cerebral small-vessel (HCSV) disease. The aim of this study was to clarify whether TGF-beta1 is a risk factor for intracranial deep white matter lesions (DWLs) and their progression in a general elderly population.

METHODS

The subjects included 81 participants (Groups DWL, DWLP, and C) who had voluntarily undergone a health examination and brain magnetic resonance imaging (MRI) in 2003 and 2008 and 43 age-matched patients with previous symptomatic brain infarctions. Deep white matter lesions were graded from Grade 0 to 3 according to the Fazekas classification. Group DWL (23 subjects) was defined as DWLs with no progression in the grade level, and Group DWLP (progression of DWL) (12 subjects) was defined as DWLs with an increase in one or more grade number and an apparent worsening of Grade 3. Forty-six age-matched control subjects with consistent normal brain MRI were included in Group C. The associations between DWLs and various vascular risk factors, including peripheral blood TGF-beta1 levels, were examined.

RESULTS

In addition to the classical risk factors, the highest TGF-beta1 levels were found in Group DWLP. The TGF-beta1 levels were significantly higher in Group DWLP than in Group DWL, and DWLP was significantly correlated with elevated TGF-beta1 levels (odds ratio [OR]  =  1·72).

CONCLUSIONS

The present data suggest that TGF-beta1 may be important in the pathogenesis and progression of DWLs, and it is expected to be useful as a clinical indicator reflecting the presence of intracranial white matter lesions.

Aging and chronic kidney disease: the impact on physical function and cognition

Evidence has recently been building that the presence of chronic kidney disease (CKD) is an independent contributor to decline in physical and cognitive functions in older adults. CKD affects 45% of persons older than 70 years of age and can double the risk for physical impairment, cognitive dysfunction, and frailty. To increase awareness of this relatively new concept of CKD as a risk factor for accelerated aging, we review studies on the association of CKD with physical function, frailty, and cognitive function. We also present a summary of the proposed mechanisms for these associations.