Cerebral small vessel disease and chronic kidney disease (CKD): Results of a cross-sectional study in community-based Japanese elderly

Association of Kidney Function With Dementia and Structural Brain Differences: A Large Population-Based Cohort Study

BACKGROUND

The association between kidney function and dementia risk and the mechanisms underlying this relationship remain unclear.

METHODS

Within the UK Biobank, 191 970 dementia-free participants aged ≥60 (mean age: 64.1 ± 2.9 years) were followed for 16 years to detect incident dementia. Serum creatinine and Cystatin C were measured at baseline to calculate estimated glomerular filtration rate (eGFR, mL/min/1.73 m2). Kidney function was categorized as normal (eGFR ≥ 90), mildly impaired (60 ≤ eGFR < 90), or moderately to severely impaired (eGFR < 60). Dementia was assessed based on self-reported medical history and medical records. During the follow-up, a subsample of 12 637 participants underwent brain MRI scans. Volumes of total brain, gray matter, white matter, hippocampus, and white matter hyperintensities were assessed.

RESULTS

Over the follow-up, 5 327 (2.8%) participants developed dementia. Compared to normal kidney function, there was an increased risk of dementia with moderate to severely impaired kidney function (hazard ratio = 1.53, 95% confidence interval [CI]: 1.32-1.76) but not mildly impaired kidney function. In Laplace regression, dementia onset among people with moderate to severely impaired kidney function occurred 1.53 (95% CI: 0.98-2.08) years earlier than those with normal kidney function. Moderate to severely impaired kidney function was related to significantly lower gray matter volume (β = -0.11, 95% CI: -0.19 to -0.03), but not to other brain magnetic resonance imaging measures.

CONCLUSIONS

Impaired kidney function is associated with about 50% increased risk of dementia and anticipates dementia onset by more than 1.5 years. Brain neurodegeneration may underlie the kidney function-dementia association.

A Scoping Review on Biomarkers of Endothelial Dysfunction in Small Vessel Disease: Molecular Insights from Human Studies

Small vessel disease (SVD) is a highly prevalent disorder of the brain's microvessels and a common cause of dementia as well as ischaemic and haemorrhagic strokes. Though much about the underlying pathophysiology of SVD remains poorly understood, a wealth of recently published evidence strongly suggests a key role of microvessel endothelial dysfunction and a compromised blood-brain barrier (BBB) in the development and progression of the disease. Understanding the causes and downstream consequences associated with endothelial dysfunction in this pathological context could aid in the development of effective diagnostic and prognostic tools and provide promising avenues for potential therapeutic interventions. In this scoping review, we aim to summarise the findings from clinical studies examining the role of the molecular mechanisms underlying endothelial dysfunction in SVD, focussing on biochemical markers of endothelial dysfunction detectable in biofluids, including cell adhesion molecules, BBB transporters, cytokines/chemokines, inflammatory markers, coagulation factors, growth factors, and markers involved in the nitric oxide cascade.

The Relationship Between Sleep and Brain Function in Older Adults With Chronic Kidney Disease and Self-Identified Cognitive Impairment

Older adults with chronic kidney disease (CKD) are at risk for cognitive impairment and sleep disturbances. The purpose of the current study was to investigate the relationship between sleep and brain structure/function in older adults with CKD and self-identified cognitive impairment. The sample (N = 37) had a mean age of 68 years (SD = 4.9 years), estimated glomerular filtration rate of 43.7 mL/min/1.73m2 (SD = 10.98), median sleep time of 7.4 hours, and was 70% female. Sleeping <7.4 hours, compared to ≥7.4 hours, was associated with better attention/information processing (β = 11.46, 95% confidence interval [CI] [3.85, 19.06]) and better learning/memory (β = 2.06, 95% CI [0.37, 3.75]). Better sleep efficiency was associated with better global cerebral blood flow (β = 3.30, 95% CI [0.65, 5.95]). Longer awake length after sleep onset was associated with worse fractional anisotropy of the cingulum (β = -0.01, 95% CI [-0.02, -0.003]). Sleep duration and continuity may be related to brain function in older adults with CKD and self-identified cognitive impairment. [Journal of Gerontological Nursing, 49(7), 31-39.].

Quantitative Proteomics of Medium-Sized Extracellular Vesicle-Enriched Plasma of Lacunar Infarction for the Discovery of Prognostic Biomarkers

Lacunar infarction (LACI), a subtype of acute ischemic stroke, has poor mid- to long-term prognosis due to recurrent vascular events or incident dementia which is difficult to predict using existing clinical data. Herein, we aim to discover blood-based biomarkers for LACI as a complementary prognostic tool. Convalescent plasma was collected from forty-five patients following a non-disabling LACI along with seventeen matched control subjects. The patients were followed up prospectively for up to five years to record an occurrence of adverse outcome and grouped accordingly (i.e., LACI-no adverse outcome, LACI-recurrent vascular event, and LACI-cognitive decline without any recurrence of vascular events). Medium-sized extracellular vesicles (MEVs), isolated from the pooled plasma of four groups, were analyzed by stable isotope labeling and 2D-LC-MS/MS. Out of 573 (FDR < 1%) quantified proteins, 146 showed significant changes in at least one LACI group when compared to matched healthy control. A systems analysis revealed that major elements (~85%) of the MEV proteome are different from the proteome of small-sized extracellular vesicles obtained from the same pooled plasma. The altered MEV proteins in LACI patients are mostly reduced in abundance. The majority of the shortlisted MEV proteins are not linked to commonly studied biological processes such as coagulation, fibrinolysis, or inflammation. Instead, they are linked to oxygen-glucose deprivation, endo-lysosomal trafficking, glucose transport, and iron homeostasis. The dataset is provided as a web-based data resource to facilitate meta-analysis, data integration, and targeted large-scale validation.

A Simple Review of Small Vessel Disease Manifestation in the Brain, Retina, and Kidneys

Small blood vessels express specific phenotypical and functional characteristics throughout the body. Alterations in the microcirculation contribute to many correlated physiological and pathological events in related organs. Factors such as comorbidities and genetics contribute to the complexity of this topic. Small vessel disease primarily affects end organs that receive significant cardiac output, such as the brain, kidney, and retina. Despite the differences in location, concurrent changes are seen in the micro-vasculature of the brain, retina, and kidneys under pathological conditions due to their common histological, functional, and embryological characteristics. While the cardiovascular basis of pathology in association with the brain, retina, or kidneys has been well documented, this is a simple review that uniquely considers the relationship between all three organs and highlights the prevalence of coexisting end organ injuries in an attempt to elucidate connections between the brain, retina, and kidneys, which has the potential to transform diagnostic and therapeutic approaches.

A Profile of Nanoparticle-Based Plasma Neurodegenerative Biomarkers for Cognitive Function Among Patients Undergoing Hemodialysis

Purpose

This study aimed to compare the plasma levels of nanoparticle-based neurodegenerative biomarkers between hemodialysis (HD) participants with grossly normal cognitive function and healthy controls.

Patients and Methods

A cohort of participants undergoing maintenance HD and healthy controls were enrolled for comparison between July and October 2021. The immunomagnetic reduction method was used to measure plasma neurodegenerative biomarkers Aβ_1-40, Aβ_1-42, tau protein, and neurofilament light chain (NfL). The clinical dementia rating (CDR) was used to evaluate cognitive function. A receiver operating characteristic curve was used to discriminate between HD participants and healthy controls.

Results

There were 52 and 18 participants in the HD and healthy control groups, respectively. The mean age of the HD participants was 62 years, and that of the healthy controls was 57 years. The mean HD vintage in the HD cohort was 11.8 years. HD participants demonstrated significantly higher plasma levels of Aβ_1-42, tau protein, Aβ_1-42 × tau, and NfL and Aβ_1-42/Aβ_1-40 ratio and significantly lower plasma Aβ_1-40 levels than healthy controls. The measured plasma biomarkers could not discriminate between CDR0 and CDR0.5 HD participants. The area under the curve of the study biomarkers to discriminate HD participants from healthy controls ranged from 0.987 (Aβ_1-42 × tau) to 0.889 (NfL).

Conclusion

The plasma levels of nanoparticle-based neurodegenerative biomarkers were higher in HD participants with grossly normal cognitive function than in healthy controls. These findings imply that neurodegenerative changes appear in HD participants. A profile of plasma neurodegenerative biomarkers could be considered a potential surrogate for evaluating long-term cognitive function in HD participants.

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.

Kidney function, brain morphology and cognition in the elderly: sex differences in the Austrian Stroke Prevention Study

Impaired kidney function is associated with structural brain changes and cognitive dysfunction. In the aging kidney, hemodynamic and structural alterations reduce the glomerular filtration rate (eGFR). Little is known about differences between men and women regarding decline of kidney function and brain damage.

In this community-based study, we assessed associations between the eGFR, focal and diffuse brain abnormalities and cognitive functions. Sex-specific effects were analyzed by interaction terms eGFR x sex on brain structure and cognition. Interactive effects were assessed using mixed-models –stratified by sex.

Overall, 196 women and 129 men (median age 68 years and mean eGFR 73.8±14.9 ml/min/1.73m²) were included. Significant associations existed between eGFR and cortical volume (β: 1.53E-04; SE: 6.72E-05; p=0.023 for neocortex). Sex exerted a significant interactive effect. Only in men, eGFR related to cortical volumes of all lobes and of deep gray matter structures (p= 0.001 for total gray matter, p=0.0004 for neocortex). In the whole group eGFR was not associated with cognition, but men with lower eGFR performed worse on tests for executive function, which, after FDR correction, was not significant.

We conclude, that in community-dwelling middle-aged and elderly individuals, reduced eGFR relates to brain volume loss in men but not in women.

Chronic kidney disease correlates with MRI findings of cerebral small vessel disease

Objective: Cerebral small vessel disease (CSVD) and chronic kidney disease (CKD) may be part of a multisystem small-vessel disorder. Since the kidney and brain share unique susceptibilities to vascular injury, kidney impairment may be predictive of the presence and severity of CSVD. This study explored the relationship between CSVD and CKD.

Methods: Between December 2015 and December 2017 (follow-up 10–20 months) 52 patients with chronic nephritis and CKD were classified into a progressive group (n = 17) and stable group (n = 35). Age, gender, hypertension, diabetes and smoking were matched between groups. CSVD features of both groups, including enlarged Virchow-Robin spaces (VRS), white matter lesions (WML), lacunar infarcts (LI), and cerebral microbleeds (CMB) were evaluated by magnetic resonance (MR) imaging.

Results: WML and CMB in the progressive group were exacerbated at follow-up compared to initial exam (p = 0.004 and 0.041, respectively). There was no significant change in VRS, WML, LI, or CMB in the stable group at follow-up compared to initial exam. CMB were significantly different between the progressive group and stable group at follow-up.etimtaed Glomerular filtration rate (eGFR) was significantly correlated with VRS, WML, and CMB at follow-up (p = 0.037, 0.041, and 0.009, respectively).

Conclusions: Patients with progressive CKD have a higher prevalence and severity of CSVD, which correlates with deterioration of renal function as assessed by decreased eGFR. Thus EGFR may also be of value in the prediction of cerebral small vessel disease.

Chronic Kidney Disease Associated with Worsening White Matter Disease and Ventricular Enlargement

BACKGROUND

Chronic kidney disease (CKD), a growing public health issue in the elderly, is associated with increased risk of cognitive impairment.

OBJECTIVE

To investigate the mechanisms through which CKD impacts brain health using longitudinal imaging.

METHODS

We identified 97 participants (74 CKD and 23 non-CKD) from the BRINK (BRain IN Kidney Disease), a longitudinal study of CKD with two MRI scans (baseline and 3-year follow-up). We measured the associations between baseline and change in kidney disease biomarkers of estimated glomerular filtration rate (eGFR) and urinary albumin to creatinine ratio (UACR), considered a measure of microvascular inflammation, and imaging outcomes of cortical thickness and ventricular volume from structural MRI, white matter hyperintensities (WMH) volume from FLAIR images, and fractional anisotropy of the corpus callosum (FACC).

RESULTS

There were white matter-specific changes as observed by increased WMH volume and decreased FACC in CKD participants, as well as ventricular volume increase in both CKD and non-CKD groups reflective of aging-related changes. Decline in eGFR was associated with decrease in the FACC, suggesting that subtle early white matter changes due to kidney disease can be captured using DTI. An increase in UACR was associated with increase in ventricular volume.

CONCLUSION

Our results support the role of eGFR as a measure of kidney microvascular disease which is associated with concurrent white matter damage in CKD. Future work is needed to investigate the possible link between endothelial microvascular inflammation (as measured by an increased UACR) and ventricular volume increase.

Difference in risk factors of silent brain infarction between paroxysmal and persistent atrial fibrillation

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Differences in risk factors for SBI between paroxysmal and persistent AF was studied.

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NVAF patients (119 paroxysmal, 71 persistent) underwent brain MRI, TTE, and TEE.

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DM and CKD, which represents microvascular disease, predicted SBI in paroxysmal AF.

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There was no obvious therapeutic target for SBI after progression to persistent NVAF.

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Intervention for DM and CKD from paroxysmal NVAF may prevent SBI and future stroke.

Background

Although silent brain infarction is an independent risk factor for subsequent symptomatic stroke and dementia in patients with nonvalvular atrial fibrillation, little is known regarding differences in risk factors for silent brain infarction between patients with paroxysmal and persistent nonvalvular atrial fibrillation.

Methods

This study population consisted of 190 neurologically asymptomatic patients (mean age, 64 ± 11 years) with nonvalvular atrial fibrillation (119 paroxysmal, 71 persistent) who were scheduled for catheter ablation. All patients underwent brain magnetic resonance imaging to screen for silent brain infarction prior to ablation. Transthoracic and transesophageal echocardiography was performed to screen for left atrial abnormalities (left atrial enlargement, spontaneous echo contrast, or left atrial appendage emptying velocity) and complex plaques in the aortic arch.

Results

Silent brain infarction was detected in 50 patients (26%) [26 patients (22%) in paroxysmal vs. 24 patients (34%) in persistent, p = 0.09]. Multiple logistic regression analysis indicated that age and diabetes mellitus or chronic kidney disease (estimated glomerular filtration rate < 60 mL/min/1.73 m²) were associated with silent brain infarction in patients with paroxysmal nonvalvular atrial fibrillation (p < 0.05), whereas no modifiable risk factors of silent brain infarction were observed in patients with persistent nonvalvular atrial fibrillation.

Conclusions

These findings suggest that intensive intervention for diabetes mellitus and renal impairment from the paroxysmal stage or ablation therapy at the time of paroxysmal stage to prevent progression to persistent nonvalvular atrial fibrillation may prevent silent brain infarction and consequently reduce the risk of future symptomatic stroke.

Long-Term Mortality Related to Acute Kidney Injury Following Intracerebral Hemorrhage: A 10-Year (2010-2019) Retrospective Study

OBJECTIVES

Acute kidney injury (AKI) following intracerebral hemorrhage (ICH) is an intractable medical complication and an independent predictor of short-term mortality. However, the correlation between AKI and long-term mortality has not been fully investigated. The aim of the present study was to determine the relationship between AKI following ICH and long-term mortality in a 10-year (2010-2019) retrospective cohort.

MATERIALS AND METHODS

A total of 1449 ICH patients were screened and enrolled at the Department of Neurosurgery, Southwest Hospital, Third Military Medical University (Army Medical University) from January 2010 to December 2016. The endpoint for follow-up was May 31, 2019. The estimated all-cause mortality was determined using Cox proportional hazard regression models.

RESULTS

Among 1449 ICH patients, 136 (9.4%) suffered from AKI, and the duration of follow-up was a median of 5.1 years (IQR 3.2-7.2). The results indicated that the risk factors for AKI without preexisting chronic kidney disease (CKD) in the multivariable analysis were age (p = 0.002), nephrotoxic antibiotics (p = 0.000), diabetes mellitus (p = 0.005), sepsis (p = 0.000), antiplatelet therapy (p = 0.002), infratentorial hemorrhage (p = 0.000) and ICH volume (p = 0.003). Age (p = 0.008), ACEIs/ARBs (p = 0.010), nephrotoxic antibiotics (p = 0.014), coronary artery disease (p = 0.009), diabetes mellitus (p = 0.014), hypertension (p = 0.000) and anticoagulant therapy (p = 0.000) were independent predictors of AKI with preexisting CKD. Meanwhile, the data demonstrated that the estimated all-cause mortality was significantly higher in ICH patients with AKI without preexisting CKD (HR 4.208, 95% CI 2.946-6.011; p = 0.000) and in ICH patients with AKI with preexisting CKD (HR 2.470, 95% CI 1.747-3.492; p = 0.000) than in those without AKI.

CONCLUSIONS

AKI is a long-term independent predictor of mortality in ICH patients. Thus, renal function needs to be routinely determined in ICH patients during clinical practice.

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.

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.

Cerebro-renal interaction and stroke

Stroke is an event causing a disturbance in cerebral function leading to death and disability worldwide. Both acute kidney injury and chronic kidney disease (CKD) are associated with an increased risk of stroke and cerebrovascular events. The underlying mechanistic approach between impaired renal function and stroke is limitedly explored and has attracted researchers to learn more for developing therapeutic intervention. Common risk factors such as hypertension, hyperphosphatemia, atrial fibrillation, arteriosclerosis, hyperhomocysteinemia, blood-brain barrier disruption, inflammation, etc. are observed in the general population, but are high in renal failure patients. Also, risk factors like bone mineral metabolism, uremic toxins, and anemia, along with the process of dialysis in CKD patients, eventually increases the risk of stroke. Therefore, early detection of risks associated with stroke in CKD is imperative, which may decrease the mortality associated with it. This review highlights mechanisms by which kidney dysfunction can lead to cerebrovascular events and increase the risk of stroke in renal impairment.

Cerebrovascular Disease and Cognition in Chronic Kidney Disease Patients

Chronic kidney disease (CKD) affects both brain structure and function. Patients with CKD have a higher risk of both ischemic and hemorrhagic strokes. Age, prior disease history, hypertension, diabetes, atrial fibrillation, smoking, diet, obesity, and sedimentary lifestyle are most common risk factors. Renal-specific pathophysiologic derangements, such as oxidative stress, chronic inflammation, endothelial dysfunction, vascular calcification, anemia, gut dysbiosis, and uremic toxins are important mediators. Dialysis initiation constitutes the highest stroke risk period. CKD significantly worsens stroke outcomes. It is essential to understand the risks and benefits of established stroke therapeutics in patients with CKD, especially in those on dialysis. Subclinical cerebrovascular disease, such as of silent brain infarction, white matter lesions, cerebral microbleeds, and cerebral atrophy are more prevalent with declining renal function. This may lead to functional brain damage manifesting as cognitive impairment. Cognitive dysfunction has been linked to poor compliance with medications, and is associated with greater morbidity and mortality. Thus, understanding the interaction between renal impairment and brain is important in to minimize the risk of neurologic injury in patients with CKD. This article reviews the link between chronic kidney disease and brain abnormalities associated with CKD in detail.

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.

Cerebral Small Vessel Disease Associated with Subclinical Vascular Damage Indicators in Asymptomatic Hypertensive Patients

Background: Cerebral small vessel disease (CSVD) is frequent in patients with cardiovascular risk factors including arterial hypertension, and it is associated with vascular damage in other organs and the risk of stroke, cognitive impairment, and dementia. Early diagnosis of CSVD could prevent deleterious consequences. Objective: To characterize CSVD associated with indicators of subclinical vascular damage in asymptomatic hypertensive patients. Materials and Methods: Participants were hypertensive (HT) and non-hypertensive (non-HT) individuals; without signs of cerebrovascular disease, dementia, and chronic renal failure. For CSVD, white matter hyperintensities (WMH), enlarged Virchow-Robin perivascular spaces (EVRPS), lacunar infarcts, and microbleeds were investigated. Subclinical vascular damage was evaluated (hypertensive retinopathy, microalbuminuria, and extracranial carotid morphology: intima media thickness (IMT) and atheroma plaque). Results: CSVD MRI findings were more frequent in HT; as well as greater intimal thickening. The IMT + plaque was significantly associated with all MRI variables; but retinopathy was correlated with EVRPS and lacunar infarcts. Only microalbuminuria was related to the greater severity of WMH in HT. Multivariate analysis evidenced that CSVD was independently associated with the combination of indicators of vascular damage and systolic blood pressure. Conclusions: Combining indicators of subclinical vascular damage, such as carotid morphological variables, microalbuminuria, and hypertensive retinopathy for early detection of CSVD in asymptomatic hypertensive patients could prove to be useful to take actions for the prevention of irreversible brain damage, which could lead to cognitive impairment, dementia and stroke.

Kidney Dysfunction Impact on White Matter Hyperintensity Volume in Neurologically Healthy Adults

The detrimental outcomes of white matter hyperintensity (WMH) are known to be proportional to WMH volume. This study aimed to evaluate the association between kidney dysfunction and white matter hyperintensity (WMH) volume. A total of 2,203 subjects who underwent brain magnetic resonance imaging (MRI) as part of a screening health check-up was included in this study. WMH was defined as hyperintensity signals without cavity formation in the white matter on fluid-attenuated inversion recovery images. WMH volume was measured quantitatively, and data were normalized by square root transformation prior to analysis. Mean age of the subjects was 56.9 years and mean WMH volume was 2.7 cm³. Mean estimated glomerular filtration rate (eGFR) level was 78.0 ml/min/1.73 m², and 172 subjects (7.8%) were diagnosed with moderate-to-severe kidney dysfunction (eGFR < 60). Mean Urine albumin-to-creatinine ratio (UACR) was 0.02, and 166 subjects showed significant albuminuria (UACR ≥ 0.03). Multivariate analyses showed that each of UACR, significant albuminuria, and moderate-to-severe kidney dysfunction was significantly associated with increased WMH volume (all p < 0.05). When we considered significant albuminuria and moderate-to-severe kidney dysfunction simultaneously, subjects with both significant albuminuria and moderate-to-severe kidney dysfunction had more than twice the WMH volume as did those in the other groups (all p < 0.05). Kidney dysfunction, defined by albuminuria and eGFR, was independently associated with WMH volume. Risk factors related to WMH and its detrimental outcomes should be strictly modified in subjects with kidney dysfunction, especially in those with both albuminuria and a reduced eGFR.

The specific impact of uremic toxins upon cognitive domains: a review

One of the mechanisms proposed for chronic kidney disease (CKD)-related cognitive impairment is the accumulation of uremic toxins due to the deterioration of the renal clearance function. Cognition can be categorized into five major domains according to its information processing functions: memory, attention, language, visual-spatial, and executive. We performed a review using the terms 'uric acid', 'indoxyl sulfate', 'p-cresyl sulfate', 'homocysteine', 'interleukins' and 'parathyroid hormone'. These are the compounds that were found to be strongly associated with cognitive impairment in CKD in the literature. The 26 selected articles point towards an association between higher levels of uric acid, homocysteine, and interleukin 6 with lower cognitive performance in executive, attentional, and memory domains. We also reviewed the hemodialysis effects on cognition. Hemodialysis seems to contribute to an amelioration of CKD-related encephalopathic dysfunction, although this improvement occurs more in some cognitive domains than in others.

Large Vessel Disease Modifies the Relationship Between Kidney Injury and Cerebral Small Vessel Disease

Background: Recent studies have shown that renal disease is associated with magnetic resonance imaging (MRI) markers of cerebral small vessel disease (CSVD), independent of traditional vascular risk factors. Although large artery lesions might be involved in the cerebrorenal association, evidence has been lacking.

Methods: A total of 928 participants from a population-based cohort study were included. Kidney injury measurements included urinary albumin-to-creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR). CSVD was assessed on MRI by white matter hyperintensity volume (WMHV), lacunes, brain parenchymal fraction (BPF), cerebral microbleeds (CMBs), and perivascular space. Carotid plaques and brachial-ankle pulse wave velocity (baPWV) were used to assess large artery atherosclerosis and stiffness. Multivariable linear and logistic regression and additional interaction models were used for statistical analysis.

Results: Individuals with elevated ACR had higher prevalence of lacunes and more WMHV (p = 0.001 and 0.000, respectively), those with decreased eGFR had smaller brain volume, higher prevalence of lacunes and deep CMBs (p = 0.009, p = 0.017) and p = 0.010 respectively). Interaction analysis revealed that carotid plaque and baPWV significantly enhanced the association between eGFR and BPF (p = 0.001 and p = 0.002, respectively), that is, the association of eGFR with BPF was only significant among participants with carotid plaque and higher baPWV. In addition, carotid plaque enhanced the association between ACR and WMHV (p = 0.034) and baPWV enhanced the association between ACR and the presence of lacunes (p = 0.027). Modifying effect of large vessel disease markers on the association between kidney injury measurements and CMBs was not significant.

Conclusion: Evaluation of subclinical CVSD in individuals with kidney injury is warranted, especially in those with combined large artery disease.

Chronic kidney disease is associated with carotid atherosclerosis and symptomatic ischaemic stroke

Objective We aimed to investigate the relationships among chronic kidney disease (CKD), symptomatic ischaemic stroke, and carotid atherosclerosis. Methods We enrolled 455 patients who underwent carotid ultrasonography in our hospital, including 311 patients with symptomatic ischaemic stroke and 144 patients without symptomatic ischaemic stroke. Carotid intima-media thickness (IMT), the rate of internal carotid artery stenosis, and maximal plaque size were evaluated. Results The mean age of the patients was 68.5 ± 11.0 years and the mean estimated glomerular filtration rate (eGFR) was 68.8 ± 18.2 mL/min/1.73 m². After adjustment for cardiovascular risk factors, the mean IMT was significantly higher in patients with CKD than in those without CKD. The IMT and eGFR were negatively correlated in patients with stroke (r = -0.169). Multiple logistic regression analyses showed that mean IMT, plaque size, and internal carotid artery stenosis were significant determinants of symptomatic ischaemic stroke after adjustment of multivariate risk factors. Furthermore, the eGFR was a negative determinant of symptomatic ischaemic stroke after adjusting for classical risk factors (odds ratio [95% confidence interval] = 0.868 [0.769-0.979]). Conclusion CKD might be associated with the carotid atherosclerosis and symptomatic ischaemic stroke.

High Circulatory Phosphate Level Is Associated with Cerebral Small-Vessel Diseases

High phosphate is linked to vascular calcification and endothelial dysfunction; however, its relationship with cerebral small-vessel diseases (CSVDs) is still unknown. Study subjects were prospectively recruited from the community-based I-Lan Longitudinal Aging Study. CSVDs including lacunes, white matter hyperintensities (WMHs), and cerebral microbleeds were evaluated using 3T magnetic resonance images. Multivariate analyses were performed to study the associations between circulatory phosphate level and the presence of CSVDs. In vitro experiments included human brain microvascular endothelial cell (HBMEC) studies and western blotting. The present study included 186 subjects (age [mean ± standard deviation, range] 64.7 ± 8.6, 50-86.8 years; 93 men). Multivariate analysis revealed that circulatory phosphate levels > 3.925 mg/dL were associated with severe WMH with an odds ratio of 3.7 (95% confidence interval = 1.3-10.6) independent of age, sex, traditional vascular risk factors, total cholesterol, renal function, or circulatory calcium level. The in vitro study revealed a downregulation of tight junction protein (zona occludens-1, occludin, and claudin-5) expression in HBMECs after 48 h of treatment with high phosphate (2.5/5 mM). We are the first to report a relationship between circulatory phosphate and CSVDs. Our results suggest that high circulatory phosphate level might be a novel risk factor for CSVD, possibly by impairing BBB structures.

Association of Kidney Function Biomarkers with Brain MRI Findings: The BRINK Study

BACKGROUND

Chronic kidney disease (CKD) studies have reported variable prevalence of brain pathologies, in part due to low inclusion of participants with moderate to severe CKD.

OBJECTIVE

To measure the association between kidney function biomarkers and brain MRI findings in CKD.

METHODS

In the BRINK (BRain IN Kidney Disease) study, MRI was used to measure gray matter volumes, cerebrovascular pathologies (white matter hyperintensity (WMH), infarctions, microhemorrhages), and microstructural changes using diffusion tensor imaging (DTI). We performed regression analyses with estimated glomerular filtration rate (eGFR) and urine albumin to creatinine ratio (UACR) as primary predictors, and joint models that included both predictors, adjusted for vascular risk factors.

RESULTS

We obtained 240 baseline MRI scans (150 CKD with eGFR <45 in ml/min/1.73 m2; 16 mild CKD: eGFR 45-59; 74 controls: eGFR≥60). Lower eGFR was associated with greater WMH burden, increased odds of cortical infarctions, and worsening diffusion changes throughout the brain. In eGFR models adjusted for UACR, only cortical infarction associations persisted. However, after adjusting for eGFR, higher UACR provided additional information related to temporal lobe atrophy, increased WMH, and whole brain microstructural changes as measured by increased DTI mean diffusivity.

CONCLUSIONS

Biomarkers of kidney disease (eGFR and UACR) were associated with MRI brain changes, even after accounting for vascular risk factors. UACR adds unique additional information to eGFR regarding brain structural and diffusion biomarkers. There was a greater impact of kidney function biomarkers on cerebrovascular pathologies and microstructural brain changes, suggesting that cerebrovascular etiology may be the primary driver of cognitive impairment in CKD.

Albuminuria Increases the Risks for Both Alzheimer Disease and Vascular Dementia in Community-Dwelling Japanese Elderly: The Hisayama Study

Background

Epidemiologic evidence has emerged to reveal an association of albuminuria and low estimated glomerular filtration rate (eGFR) with dementia, but the findings are inconsistent. In addition, there are limited studies addressing the association between albuminuria and Alzheimer disease (AD).

Methods and Results

A total of 1562 community‐dwelling Japanese subjects aged ≥60 years without dementia were followed up for 10 years. The outcomes were incidence of all‐cause dementia and its subtypes, namely, AD and vascular dementia (VaD). The hazard ratios for the outcomes were estimated according to urine albumin–creatinine ratio (UACR) and eGFR levels using a Cox proportional hazards model. During the follow‐up, 358 subjects developed all‐cause dementia (238 AD and 93 VaD). Higher UACR level was significantly associated with greater multivariable‐adjusted risks of all‐cause dementia (hazard ratios [95% confidence intervals]: 1.00 [reference], 1.12 [0.78–1.60], 1.65 [1.18–2.30], and 1.56 [1.11–2.19] for UACR of ≤6.9, 7.0–12.7, 12.8–29.9, and ≥30.0 mg/g, respectively), AD (1.00 [reference], 1.20 [0.77–1.86], 1.75 [1.16–2.64], and 1.58 [1.03–2.41], respectively), and VaD (1.00 [reference], 1.03 [0.46–2.29], 1.94 [0.96–3.95], and 2.19 [1.09–4.38], respectively). On the other hand, lower eGFR level was marginally associated with greater risk of VaD, but not AD. Subjects with UACR ≥12.8 mg/g and eGFR of <60 mL/min per 1.73 m² had 3.3‐fold greater risk of VaD than those with UACR <12.8 mg/g and eGFR of ≥60 mL/min per 1.73 m².

Conclusions

Albuminuria is a significant risk factor for the development of both AD and VaD in community‐dwelling Japanese elderly. Moreover, albuminuria and low eGFR are mutually associated with a greater risk of VaD.

Understanding the direction of the relationship between white matter hyperintensities of vascular origin, sleep quality, and chronic kidney disease-Results from the Atahualpa Project

OBJECTIVE

The burden of cerebral small vessel disease, sleep disorders, and chronic kidney disease is on the rise in remote rural settings. However, information on potential links between these conditions is limited. We aimed to assess the relationships between these conditions in community-dwelling older adults living in rural Ecuador.

PATIENTS AND METHODS

Atahualpa residents aged ≥60 years were offered a brain MRI. A venous blood sample was obtained for serum creatinine determination. Baseline interviews and procedures were directed to assess demographics, cardiovascular risk factors, and sleep quality. Using generalized structural equation modeling (GSEM), we assessed the associations between white matter hyperintensities (WMH) of vascular origin, sleep quality and kidney function, as well as the directions of the relationships between these variables.

RESULTS

Of 423 candidates, 314 (74%) were enrolled. Moderate-to-severe WMH were noticed in 74 (24%) individuals, poor sleep quality in 101 (31%), and moderate-to-severe chronic kidney disease in 28 (9%). GSEM showed that the direction of the effect was from kidney function to WMH and from the latter to sleep quality. Of independent variables investigated, worse kidney function was associated with age, high glucose levels and male sex. WMH was associated with cholesterol blood levels, blood pressure, level of education and severe edentulism. Poor sleep quality was associated with poor physical activity.

CONCLUSION

This population based study shows that chronic kidney disease is associated with increased severity of WMH, which, in turn, is associated with a poor sleep quality.

Range in systolic blood pressure and care-needs certification in long-term care insurance in community-dwelling older patients with chronic kidney disease

Objective Low systolic blood pressure (SBP) is associated with an increased risk for cardiovascular morbidity/mortality in older patients with chronic kidney disease (CKD). The present study evaluated the association between range in blood pressure and first care-needs certification in the Long-term Care Insurance (LTCI) system or death in community-dwelling older subjects with or without CKD. Methods CKD was defined as an estimated glomerular filtration rate <60 ml/min/1.73 m² or dipstick proteinuria of + or greater. Our study was conducted in 1078 older subjects aged 65-94 years. Associations were estimated using the Cox proportional hazards model. Results During 5 years of follow-up, 135 first certifications and 53 deaths occurred. Among patients with CKD, moderate SBP (130-159 mmHg) was associated with a significantly lower adjusted risk of subsequent total certification (hazard ratio [HR] = 0.44) and subsequent certification owing to dementia (HR = 0.17) compared with SBP < 130 mmHg. These relationships were not observed in non-CKD subjects. Conclusion Lower SBP of <130 mmHg may predict a higher risk for subsequent first care-needs certification in LTCI, especially for dementia, in community-dwelling patients with CKD.

Kidney dysfunction and silent brain infarction in generally healthy adults

BACKGROUND

The association between silent brain infarction (SBI) and estimated glomerular filtration rate (eGFR)-based kidney dysfunction has not yet been definitively confirmed. This study aimed to investigate the association in generally healthy adults without a previous history of stroke or overt kidney disease.

METHODS

The data from the screening health check-up program in the Seoul National University Hospital Health Promotion Center from January 1, 2009 to December 31, 2013 were used. A total of 2594 subjects who underwent brain MRI as part of health screening were included. SBIs were identified using T2-weighted and FLAIR images. Kidney dysfunction was defined as eGFR<60ml/min/1.73m². To assess the effect of kidney dysfunction on the small perforating branches of cerebral vessels, subgroup analysis was performed using the presence of SLI as a dependent variable.

RESULTS

The mean age was 56.8±9.3years, and 1422 subjects (54.8%) were male. The mean eGFR level was 81.9±15.4ml/min/1.73m². The prevalence rates of kidney dysfunction and SBI were 5.1% and 7.1%, respectively. A higher proportion of subjects with SBI had kidney dysfunction than subjects without SBI (14.6% vs. 4.4%). The number of SBI lesions tended to increase with the progression of kidney dysfunction (p for trend<0.001). In multivariate logistic regression analyses, kidney dysfunction was significantly associated with the presence of SBI (adjusted odd ratio=1.99 to 2.21 in all four models). The same significant association was consistently identified in subgroup analyses using silent lacunar infarction (adjusted odd ratio=1.71 to 1.87 in all four models).

CONCLUSION

Kidney dysfunction was found to be an independent risk factor for the presence and number of SBI in generally healthy adults. Physicians treating patients with a decreased creatinine-based eGFR level should try to identify and modify the coexisting risk factors of stroke followed by SBI.

Effect of Kidney Dysfunction on Cerebral Cortical Thinning in Elderly Population

Chronic kidney disease has been linked to cognitive impairment and morphological brain change. However, less is known about the impact of kidney functions on cerebral cortical thickness. This study investigated the relationship between kidney functions and global or lobar cerebral cortical thickness (CTh) in 259 non-demented elderly persons. Forty-three participants (16.7%) had kidney dysfunction, which was defined as either a glomerular filtration rate (GFR) of <60 ml/min/1.73 m² or presence of proteinuria. Kidney dysfunction was associated with lower global (β = −0.05, 95% CI = −0.08 to −0.01) as well as frontal, parietal, temporal, occipital, and insular lobar CTh. In the stratified analysis, the associations were more pronounced in women, APOEε4 non-carriers, and participants with a lower cognitive score. Besides, kidney dysfunction significantly increased the risk of cortical thinning, defined as being the lowest CTh tertile, in the insular lobe (adjusted odds ratio = 2.74, 95% CI = 1.31−5.74). Our results suggested that kidney dysfunction should be closely monitored and managed in elderly population to prevent neurodegeneration.

Cognitive Impairment in Chronic Kidney Disease: Vascular Milieu and the Potential Therapeutic Role of Exercise

Chronic kidney disease (CKD) is considered a model of accelerated aging. More specifically, CKD leads to reduced physical functioning and increased frailty, increased vascular dysfunction, vascular calcification and arterial stiffness, high levels of systemic inflammation, and oxidative stress, as well as increased cognitive impairment. Increasing evidence suggests that the cognitive impairment associated with CKD may be related to cerebral small vessel disease and overall impairment in white matter integrity. The triad of poor physical function, vascular dysfunction, and cognitive impairment places patients living with CKD at an increased risk for loss of independence, poor health-related quality of life, morbidity, and mortality. The purpose of this review is to discuss the available evidence of cerebrovascular-renal axis and its interconnection with early and accelerated cognitive impairment in patients with CKD and the plausible role of exercise as a therapeutic modality. Understanding the cerebrovascular-renal axis pathophysiological link and its interconnection with physical function is important for clinicians in order to minimize the risk of loss of independence and improve quality of life in patients with CKD.

Prognostic Relationships between Microbleed, Lacunar Infarction, White Matter Lesion, and Renal Dysfunction in Acute Ischemic Stroke Survivors

BACKGROUND

It is well known that renal dysfunction and cerebral small-vessel disease (SVD), including microbleed, lacunar infarction, and white matter lesion (WML), are associated with poor prognosis after ischemic stroke. However, the prognostic relationship between renal dysfunction and SVD has not been well evaluated in acute ischemic stroke survivors. Therefore, in this study, we evaluated the prognostic relationships between estimated glomerular filtration rate (eGFR) and cerebral SVD after acute ischemic stroke.

METHODS

We retrospectively reviewed the clinical and radiological data of acute ischemic stroke survivors with decreased eGFR (<60 mL/min/1.73 m², n = 128) and controls (eGFR ≥60 mL/min/1.73 m², n = 128). The presence of SVD was evaluated according to magnetic resonance imaging performed on admission. Mortality data were obtained from medical chart reviews and telephone interviews.

RESULTS

Patients with silent lacunar infarction, WML, or microbleed had lower eGFR than patients without such lesions (60.4 ± 34.8 versus 87.5 ± 28.4 mL/min/1.73 m², 60.5 ± 37.1 versus 73.9 ± 33.3 mL/min/1.73 m², and 57.6 ± 33.3 versus 73.9 ± 32.9 mL/min/1.73 m², respectively). In addition, the multivariate adjusted odds ratio for the presence of SVD increased inversely with eGFR. Three-year survival was lower in patients with renal dysfunction and each type of SVD. The presence of WML was an independent risk factor for cardiovascular death.

CONCLUSIONS

Renal impairment was associated with the presence of SVD in acute ischemic stroke survivors. Both renal impairment and the presence of SVD were predictors of poor poststroke survival.

Kidney function is associated with severity of white matter hyperintensity in patients with acute ischemic stroke/TIA

Background

Previous studies suggested the potential interactions between cerebrovascular diseases and impaired renal function. However, the relationship between renal function and white matter hyperintensity (WMH), marker of cerebral small vessel disease, in patients with acute ischemic stroke (AIS) or transient ischemic attack (TIA) remains unknown.

Methods

We consecutively enrolled 1632 subjects with AIS or TIA who underwent brain MRI for this analysis. The severity of WMH in both of periventricular (PVH) and deep subcortical white matter (SDWMH) was evaluated using Fazekas scale. Estimated glomerular filtration rate (eGFR) was calculated by the equation of the Modification Diet for Renal Disease. Multinomial logistic regression was performed to evaluate the association between the severity of WMH and eGFR.

Results

Advanced age and hypertension were independently associated with the severity of both PVH and SDWMH (all p < 0.001). There is a significantly inverse association between eGFR and PVH. Patients having each 30 ml/min/1.73 m² increase in eGFR was associated with 75 % of risk of having degree 3 of WMH in periventricular areas compared with degree 0 (p = 0.04, OR = 0.75, 95 % CI 0.61–0.92). However this inverse association was not found between eGFR and SDWMH (P = 0.50, OR = 0.93, 95 % CI0.75–1.14).

Conclusion

Our study demonstrates that renal dysfunction (eGFR) is independently associated with the severity of PVH but not SDWMH in patients with acute ischemic stroke. This results highlighted different pathological mechanism and risk factors of PVH and SDWMH.

Gray matter volume and white matter lesions in chronic kidney disease: exploring the association with depressive symptoms

OBJECTIVE

Chronic kidney disease (CKD) is associated with structural brain damage and with a high prevalence of depression. We therefore investigated structural brain alterations in both gray and white matter in CKD patients, focusing on depression-related (frontal-subcortical) regions.

METHOD

This cross-sectional MRI study in 24 CKD patients and 24 age- and sex-matched controls first tested whether CKD was associated with regionally lower gray matter (GM) volumes and more severe white matter lesions (WMLs). In exploratory subanalyses, we examined whether differences were more pronounced in CKD patients with depressive symptoms.

RESULTS

CKD patients showed lower global GM volume (P=.04) and more severe WMLs (P=.04) compared to controls. In addition, we found substantial clusters of lower GM in the bilateral orbitofrontal-cortex for CKD patients, which were however nonsignificant after proper multiple-comparison correction. In exploratory analyses for depressed CKD patients, reduced GM clusters were mainly detected within the frontal lobe. WML severity was unrelated to depression.

CONCLUSION

CKD was characterized by differences in brain structure. Although subthreshold, lower GM volumes were observed in depression-related brain areas and were more pronounced for depressed patients. There is a need for replication in larger and longitudinal studies to investigate whether WMLs and regional GM reductions may render CKD patients more susceptible for depression.

Albuminuria, Cerebrovascular Disease and Cortical Atrophy: among Cognitively Normal Elderly Individuals

We tested the hypothesis that decreased glomerular filtration rate and albuminuria have different roles in brain structure alterations. We enrolled 1,215 cognitively normal individuals, all of whom underwent high-resolution T1-weighted volumetric magnetic resonance imaging scans. The cerebral small vessel disease burdens were assessed with white matter hyperintensities (WMH), lacunes, and microbleeds. Subjects were considered to have an abnormally elevated urine albumin creatinine ratio if the value was ≥17 mg/g for men and ≥25 mg/g for women. Albuminuria, but not estimated glomerular filtration rate (eGFR), was associated with increased WMH burdens (p = 0.002). The data was analyzed after adjusting for age, sex, education, history of hypertension, diabetes mellitus, hyperlipidemia, ischemic heart disease, stroke, total cholesterol level, body mass index, status of smoking and alcohol drinking, and intracranial volume. Albuminuria was also associated with cortical thinning, predominantly in the frontal and occipital regions (both p < 0.01) in multiple linear regression analysis. However, eGFR was not associated with cortical thickness. Furthermore, path analysis for cortical thickness showed that albuminuria was associated with frontal thinning partially mediated by WMH burdens. The assessment of albuminuria is needed to improve our ability to identify individuals with high risk for cognitive impairments, and further institute appropriate preventive measures.

Circulating biologic markers of endothelial dysfunction in cerebral small vessel disease: A review

The term cerebral small vessel disease (SVD) refers to a group of pathologic processes with various etiologies that affect small arteries, arterioles, venules, and capillaries of the brain. Magnetic resonance imaging (MRI) correlates of SVD are lacunes, recent small subcortical infarcts, white-matter hyperintensities, enlarged perivascular spaces, microbleeds, and brain atrophy. Endothelial dysfunction is thought to have a role in the mechanisms leading to SVD-related brain changes, and the study of endothelial dysfunction has been proposed as an important step for a better comprehension of cerebral SVD. Among available methods to assess endothelial function in vivo, measurement of molecules of endothelial origin in peripheral blood is currently receiving selective attention. These molecules include products of endothelial cells that change when the endothelium is activated, as well as molecules that reflect endothelial damage and repair. This review examines the main molecular factors involved in both endothelial function and dysfunction, and the evidence linking endothelial dysfunction with cerebral SVD, and gives an overview of clinical studies that have investigated the possible association between endothelial circulating biomarkers and SVD-related brain changes.

Biomarkers of Renal Function in Type 2 Diabetic Patients with Cognitive Impairment

Kidney disease is associated with cognitive impairment in studies of nondiabetic adults. We examined the cross-sectional relation between three measures of renal function and cognitive impairment (CI) in type 2 diabetic patients. A total of 357 patients with type 2 diabetes were prospectively enrolled. There were 108 patients with CI and 249 patients without CI (control). We calculated the urinary albumin/creatinine ratio (UACR) from morning spot urine and the estimated glomerular filtration rate (eGFR) in serum samples. Serum Cystatin C (Cys C) was measured with an automated particle-enhanced turbidimetric immunoassay. UACR and Cystatin C levels were significantly higher in patients with CI than those without CI (P<0.001), and the eGFR was lower in patients with CI than those without (P=0.003). A logistic regression analysis indicates that kidney impairment biomarkers levels were significantly associated with an increased risk of CI after adjustment for age and gender. The OR of each kidney biomarker (eGFR, UACR, Cystatin C) for CI status was 1.78 (0.89-3.27), 2.36 (1.29-4.42), and 2.77 (1.36-5.97), respectively. Among three kidney biomarkers (eGFR, UACR, Cystatin C), only elevated serum Cystatin C was associated with increased risk of CI in type 2 diabetic patients, with an OR of 1.42 (1.25-4.24) after additional adjustment for duration of diabetes, hypertension, hyperlipidemia, hemoglobin A1c (HbA1c), high-sensitivity C-reactive protein (Hs-CRP), intima-media thickness (IMT), ankle brachial index (ABI), and brachial-ankle pulse wave velocity (ba-PWV). Furthermore, combination of conventional risk factors and Cystatin C levels exhibited a fair diagnostic value for CI, with an area under the curve (AUC) of 0.91. Among three kidney impairment biomarkers (eGFR, UACR, Cystatin C), only elevated serum Cystatin C was associated with increased risk of CI in type 2 diabetic patients, independent of conventional risk factors. Furthermore, Cystatin C may be a better marker for CI than eGFR and UACR, and exhibited diagnostic value.

Is type 2 diabetes related to leukoaraiosis? an updated review

A significantly increased interest has been dedicated to the study of the effects of diabetes mellitus (DM) on the brain. DM is associated with an increased risk of stroke and cognitive decline. In patients with DM, neuroimaging discloses with high-frequency structural changes, such as cerebral atrophy, infarcts and white matter lesions, also called leukoaraiosis (LA), an expression of small vessel disease. A previous review showed a relation between DM and both cerebral atrophy and lacunar infarcts, while the question about the relation between DM and LA remained unanswered. In this review, we provide an update on data on this last association. In the reviewed studies, we examined the presence of DM, other disease characteristics, such as duration and complications, and laboratory markers of the disease such as blood glycated hemoglobin (HbA1c), insulin resistance, insulin concentrations and their association with LA. About 40% of the reviewed studies reported a statistically significant association between DM and LA. Long-standing DM and a poor glycemic control were associated with severe LA. Studies using innovative MRI techniques, such as diffusion tensor imaging (DTI), reported a significant association between microstructural white matter alterations and DM. This review highlights more firmly than previously reported the existence of a relation between DM and both presence and severity of LA. These results are possibly due to more sensitive and advanced imaging techniques recently used to study the extent of LA. However, because of the heterogeneous methodology used in the reviewed studies, a definitive conclusion cannot be drawn.

Endothelial cells and human cerebral small vessel disease

Brain endothelial cells have unique properties in terms of barrier function, local molecular signaling, regulation of local cerebral blood flow (CBF) and interactions with other members of the neurovascular unit. In cerebral small vessel disease (arteriolosclerosis; SVD), the endothelial cells in small arteries survive, even when mural pathology is advanced and myocytes are severely depleted. Here, we review aspects of altered endothelial functions that have been implicated in SVD: local CBF dysregulation, endothelial activation and blood-brain barrier (BBB) dysfunction. Reduced CBF is reported in the diffuse white matter lesions that are a neuroradiological signature of SVD. This may reflect an underlying deficit in local CBF regulation (possibly via the nitric oxide/cGMP signaling pathway). While many laboratories have observed an association of symptomatic SVD with serum markers of endothelial activation, it is apparent that the origin of these circulating markers need not be brain endothelium. Our own neuropathology studies did not confirm local endothelial activation in small vessels exhibiting SVD. Local BBB failure has been proposed as a cause of SVD and associated parenchymal lesions. Some groups find that computational analyses of magnetic resonance imaging (MRI) scans, following systemic injection of a gadolinium-based contrast agent, suggest that extravasation into brain parenchyma is heightened in people with SVD. Our recent histochemical studies of donated brain tissue, using immunolabeling for large plasma proteins [fibrinogen, immunoglobulin G (IgG)], do not support an association of SVD with recent plasma protein extravasation. It is possible that a trigger leakage episode, or a size-selective loosening of the BBB, participates in SVD pathology.

Renal dysfunction is associated with deep cerebral microbleeds but not white matter hyperintensities in patients with acute intracerebral hemorrhage

Kidney disease is a risk factor for cerebral microangiopathy and spontaneous intracerebral hemorrhage (ICH). We aimed to determine the association of renal dysfunction (RD) with MRI correlates of different patterns of cerebral microangiopathies including cerebral microbleeds (CMB) and white matter lesions (WML) in patients with ICH. In a prospectively collected, single-center cohort of ICH patients, glomerular filtration rate (eGFR) was estimated using the Modification of Diet in Renal Disease equation. We classified the renal function in five categories: category 1 (eGFR ≥ 90 mL/min/1.73 m(2)), category 2 (eGFR 60-89), category 3 (eGFR 30-59), category 4 (eGFR 15-29), and category 5 (eGFR <15) and dichotomized at an eGFR of 60. Number, location, and extent of CMB and WML were measured on MRI. ICH and CMB locations were classified as lobar or deep. 97 ICH patients with MRI (mean age 65.9 ± 13.9 years) were included. Intracerebral hemorrhage was lobar in 52.6 %. Median eGFR was 85.8 mL/min/1.73 m(2) (IQR 34.3). Renal dysfunction was present in 12.4 % of the patients. At least one CMB was present in 57.7 % of patients, WML were even more frequent (97.7 %). Age and impaired renal function were factors independently associated with the presence of CMB. The presence of CMB was independently associated with the number and extent of WML. RD is a frequent comorbidity in patients with ICH. Associations of RD with hypertension and with CMB in deep location suggest a predominant impact of RD on deep rather than on lobar microangiopathy.

Chronic Kidney Disease in Patients With Lacunar Stroke: Association With Enlarged Perivascular Spaces and Total Magnetic Resonance Imaging Burden of Cerebral Small Vessel Disease

BACKGROUND AND PURPOSE

The relationship between chronic kidney disease and cerebral small vessel disease (cSVD), especially enlarged perivascular spaces (EPVS), has not been fully understood. This study aimed to investigate the association of chronic kidney disease and EPVS, as well as the total burden of cSVD on magnetic resonance imaging, expressed by the simultaneous presence of multiple markers of cSVD, among patients with first-ever lacunar stroke.

METHODS

Four hundred and thirteen consecutive patients were prospectively enrolled. Centrum semiovale and basal ganglia EPVS on T2-weighted magnetic resonance imaging, as well as other imaging markers of cSVD, including lacune, white matter lesions, and cerebral microbleeds, were rated using validated scales. Chronic kidney disease was defined as either reduced estimated glomerular filtration rate or the presence of proteinuria.

RESULTS

After adjustments for potential confounders by logistic regression, proteinuria and impaired estimated glomerular filtration rate were correlated with the severity of EPVS in both centrum semiovale (odds ratio [OR] 2.59; 95% confidence interval [CI] 1.19-5.64 and OR 2.37; 95% CI 1.19-4.73) and basal ganglia (OR 5.12; 95% CI 2.70-12.10 and OR 4.17; 95% CI 2.08-8.37). A similar association was also found between proteinuria and low estimated glomerular filtration rate levels and the comprehensive cSVD burden (OR 2.13; 95% CI 1.10-4.14 and OR 5.59; 95% CI 2.58-12.08).

CONCLUSIONS

Proteinuria and impaired estimated glomerular filtration rate are associated with increasing EPVS severity and, furthermore, accumulated magnetic resonance imaging burden of cSVD in patients with first-ever acute lacunar stroke.

Association of mild kidney dysfunction with silent brain lesions in neurologically normal subjects

Background

Chronic kidney disease (CKD) has been closely associated with stroke. Although a large number of studies reported the relationship between CKD and different types of asymptomatic brain lesions, few comprehensive analyses have been performed for all types of silent brain lesions.

Methods

We performed a cross-sectional study involving 1,937 neurologically normal subjects (mean age 59.4 years). Mild CKD was defined as an estimated glomerular filtration rate between 30 and 60 ml/min/1.73 m² or positive proteinuria.

Results

The prevalence of mild CKD was 8.7%. Univariate analysis revealed an association between CKD and all silent brain lesions, including silent brain infarction, periventricular hyperintensity, subcortical white matter lesion, and microbleeds, in addition to hypertension and diabetes mellitus after adjusting for age and sex. In binary logistic regression analysis, the presence of CKD was a significant risk factor for all types of silent brain lesions, independent of other risk factors.

Conclusions

These results suggest that mild CKD is independently associated with all types of silent brain lesions, even in neurologically normal subjects.

Cerebral structural changes in diabetic kidney disease: African American-Diabetes Heart Study MIND

OBJECTIVE

Albuminuria and reduced kidney function are associated with cognitive impairment. Relationships between nephropathy and cerebral structural changes remain poorly defined, particularly in African Americans (AAs), a population at higher risk for both cognitive impairment and diabetes than European Americans. We examined the relationship between urine albumin:creatinine ratio (UACR), estimated glomerular filtration rate (eGFR), and cerebral MRI volumes in 263 AAs with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Cross-sectional associations between renal parameters and white matter (WM), gray matter (GM), hippocampal, and WM lesion (WML) volumes were assessed using generalized linear models adjusted for age, education, sex, BMI, hemoglobin A1c (HbA1c) level, and hypertension.

RESULTS

Participants had a mean (SD) age of 60.2 years (9.7 years), and 62.7% were female. Mean diabetes duration was 14.3 years (8.9 years), HbA1c level was 8.2% (2.2%; 66 mmol/mol), eGFR was 86.0 mL/min/1.73 m(2) (23.2 mL/min/1.73 m(2)), and UACR was 155.8 mg/g (542.1 mg/g; median 8.1 mg/g). Those with chronic kidney disease (CKD) (eGFR <60 mL/min/1.73 m(2) or UACR >30 mg/g) had smaller GM and higher WML volumes. Higher UACR was significantly associated with higher WML volume and greater atrophy (larger cerebrospinal fluid volumes), and smaller GM and hippocampal WM volumes. A higher eGFR was associated with larger hippocampal WM volumes. Consistent with higher WML volumes, participants with CKD had significantly poorer processing speed and working memory. These findings were independent of glycemic control.

CONCLUSIONS

We found albuminuria to be a better marker of cerebral structural changes than eGFR in AAs with type 2 diabetes. Relationships between albuminuria and brain pathology may contribute to poorer cognitive performance in patients with mild CKD.

Cerebral small vessel disease and chronic kidney disease

Chronic kidney disease, defined by a decreased glomerular filtration rate or albuminuria, is recognized as a major global health burden, mainly because it is an established risk factor for cardiovascular and cerebrovascular diseases. The magnitude of the effect of chronic kidney disease on incident stroke seems to be higher in persons of Asian ethnicity. Since the kidney and brain share unique susceptibilities to vascular injury due to similar anatomical and functional features of small artery diseases, kidney impairment can be predictive of the presence and severity of cerebral small vessel diseases. Chronic kidney disease has been reported to be associated with silent brain infarcts, cerebral white matter lesions, and cerebral microbleeds, independently of vascular risk factors. In addition, chronic kidney disease affects cognitive function, partly via the high prevalence of cerebral small vessel diseases. Retinal artery disease also has an independent relationship with chronic kidney disease and cognitive impairment. Stroke experts are no longer allowed to be ignorant of chronic kidney disease. Close liaison between neurologists and nephrologists can improve the management of cerebral small vessel diseases in kidney patients.

Cerebral small vessel disease and renal function: systematic review and meta-analysis

Background

The small vessel disease (SVD) that appears in the brain may be part of a multisystem disorder affecting other vascular beds such as the kidney and retina. Because renal failure is associated with both stroke and white matter hyperintensities we hypothesised that small vessel (lacunar) stroke would be more strongly associated with renal failure than cortical stroke. Therefore, we performed a systematic review and meta-analysis to establish first if lacunar stroke was associated with the renal function, and second, if cerebral small vessel disease seen on the MRI of patients without stroke was more common in patients with renal failure.

Methods

We searched Medline and EMBASE for studies in adults with cerebral SVD (lacunar stroke or white matter hyper intensities (WMH) on Magnetic Resonance Imaging (MRI)), in which renal function was assessed (estimated glomerular filtration rate (eGFR) or proteinuria). We extracted data on SVD diagnosis, renal function, demographics and comorbidities. We performed two meta-analyses: first, we calculated the odds of renal impairment in lacunar (small vessel) ischaemic stroke compared to other ischaemic stroke subtypes (non-small vessel disease); and second, we calculated the odds of renal impairment in non-stroke individuals with WMH on MRI compared to individuals without WMH. We then performed a sensitivity analysis by excluding studies with certain characteristics and repeating the meta-analysis calculation.

Results

After screening 11,001 potentially suitable titles, we included 37 papers reporting 32 studies of 20,379 subjects: 15 of stroke patients and 17 of SVD features in non-stroke patients. To diagnose lacunar stroke, 13/15 of the studies used risk factor-based classification (none used diffusion-weighted MRI). 394/1,119 (35%) of patients with lacunar stroke had renal impairment compared with 1,443/4,217 (34%) of patients with non-lacunar stroke, OR 0.88, (95% CI 0.6-1.30). In individuals without stroke the presence of SVD was associated with an increased risk of renal impairment (whether proteinuria or reduced eGFR) OR 2.33 (95% CI 1.80-3.01), when compared to those without SVD. After adjustment for age and hypertension, 15/21 studies still reported a significant association between renal impairment and SVD.

Conclusion

We found no specific association between renal impairment and lacunar stroke, but we did find that in individuals who had not had a stroke, having more SVD features on imaging was associated with a worse renal function, which remained significant after controlling for hypertension. However, this finding does not exclude a powerful co-associate effect of age or vascular risk factor exposure. Future research should subtype lacunar stroke sensitively and control for major risk factors.

Reduced estimated glomerular filtration rate affects outcomes 3 months after intracerebral hemorrhage: the stroke acute management with urgent risk-factor assessment and improvement-intracerebral hemorrhage study

BACKGROUND

The effect of renal dysfunction on intracerebral hemorrhage (ICH) remains unclear. We investigated associations of renal dysfunction assessed by estimated glomerular filtration rate (eGFR) with clinical courses and outcomes in ICH patients.

METHODS

From a prospective, multicenter, observational study, 203 patients who had supratentorial ICH within 3 hours of onset were included. Patients were classified into 3 groups based on eGFR: Group 1 (eGFR < 60 mL/minute/m(2)), Group 2 (60-89), and Group 3 (≥ 90). Outcomes included neurologic deterioration within 72 hours, hematoma expansion (> 33% in volume) at 24 hours, and favorable (modified Rankin Scale [mRS] ≤ 2) or unfavorable (mRS ≥ 5) outcome at 3 months.

RESULTS

Thirty-seven patients (16 women, 74.6 ± 13.2 years) were assigned to Group 1, 99 (34 women, 65.2 ± 11.4 years) to Group 2, and 67 (30 women, 61.3 ± 9.4 years) to Group 3. Significant differences were found in age (P < .001) and initial systolic blood pressure among the groups (208.4 ± 18.0, 201.9 ± 15.1, and 198.1 ± 14.2 mm Hg for Group 1, 2, and 3, respectively; P = .006). Similar rates of neurologic deterioration (14%, 6%, and 6%) and hematoma expansion (16%, 14%, and 18%) were observed among the groups. However, in Group 1, favorable outcome was less frequent (17%, 48%, and 42%; P = .002) and unfavorable outcome was more frequent (24%, 7%, and 6%; P = .013) than in the other groups. After adjustment for confounders, eGFR < 60 mL/minute/m(2) was independently associated with both favorable outcome (odds ratio [OR], .21; 95% CI, .07-.54) and unfavorable outcome (OR, 5.64; 95% CI, 1.80-18.58).

CONCLUSIONS

Renal dysfunction (eGFR < 60 mL/minute/m(2)) was associated with poor clinical outcome after ICH.

25-vitamin D, 1,25-vitamin D, parathyroid hormone, fibroblast growth factor-23 and cognitive function in men with advanced CKD: a veteran population

Abstract. Cognitive impairment is common in advanced chronic kidney disease (CKD), but little is known about its relation with abnormalities in mineral metabolism. Methods: The longitudinal association between plasma 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), intact parathyroid hormone (iPTH), and fibroblast growth factor-23 (FGF-23) levels and cognitive function was assessed in 605 patients (67 ± 12 years) with advanced CKD not requiring dialysis (n = 247) or end-stage renal disease (ESRD; n = 358) who participated in the Homocysteine Study Cognitive Function Substudy (HOSTCOG)). Cognitive function was assessed using the Telephone Interview for Cognitive Status-modified (TICSm; mean follow-up 3.1 years) and associated with baseline mineral metabolite levels using linear regression analyses. Results: In unadjusted analyses, increasing log 1,25(OH)2D and decreasing log iPTH and FGF-23 levels were associated with worse cognitive status (p < 0.05). In fully adjusted multivariate analyses, the associations were no longer significant. Log 25(OH)D levels were not associated with cognitive function in unadjusted or adjusted analyses. Results were similar when analyzed by tertile or separately within CKD and ESRD groups. Conclusions: These results suggest that mineral metabolism dysregulation does not mediate the impairment in cognitive function common in advanced CKD.