Cystatin C, a novel indicator of renal function, reflects severity of cerebral microbleeds

A bibliometric analysis of cerebral microbleeds and cognitive impairment

BACKGROUND AND OBJECTIVES

Cerebral microbleeds (CMBs) are imaging markers for small cerebral vascular diseases, which can accumulate and impact the corresponding brain networks. CMBs can affect cognitive function, including executive function, information processing speed, and visuospatial memory. Bibliometrics is a scientific and innovative method that can analyze and visualize the scientific field quantitatively. In this study, we aimed to use bibliometric analysis to demonstrate the relationship and mechanisms between CMBs and cognitive impairment. Furthermore, we reviewed the relationship between CMBs and different cognitive disorders. The use of bibliometrics can help further clarify this relationship.

METHODS

We retrieved articles on CMBs and cognitive impairment from the Web of Science Core Collection. The keywords (such as stroke, dementia, and cerebral amyloid angiopathy), authors, countries, institutions and journals, in the field were visually analyzed using VOSviewer software and bibliometric websites.

RESULTS

This bibliometric analysis reveals the related trends of CMBs in the field of cognitive impairment. CMBs, along with other small vascular lesions, constitute the basis of cognitive impairment, and studying CMBs is essential to understand the mechanisms underlying cognitive impairment.

CONCLUSION

This bibliometric analysis reveals a strong link between CMBs and cognitive impairment-related diseases and that specific brain networks were affected by CMBs. This provides further insights into the possible mechanisms and causes of CMBs and cognitive impairment. The direct and indirect damage (such as oxidative stress and neuroinflammation) to the brain caused by CMBs, destruction of the frontal-subcortical circuits, elevated Cystatin C levels, and iron deposition are involved in the occurrence and development of cognitive impairment. CMBs may be a potential marker for detecting, quantifying, and predicting cognitive impairment.

Association of Serum Cystatin C With Cerebral Small Vessel Disease in Community-Based Population

BACKGROUND:

The aim of this study was to investigate the relationship between serum cystatin C levels and the presence and severity of cerebral small vessel disease (CSVD).

METHODS:

Community-dwelling residents in the Lishui city in China from the cross-sectional survey of the PRECISE (Poly-Vascular Evaluation for Cognitive Impairment and Vascular Events) cohort study were included in present study from 2017 to 2019. Total CSVD burden and modified total CSVD burden score, as well as the markers of CSVD on magnetic resonance imaging, including white matter hyperintensity, lacunes, cerebral microbleeds, and perivascular spaces, were assessed at baseline survey. Participants were divided into 4 groups according to the quartiles of cystatin C. The association of serum cystatin C with total CSVD burden and imaging markers was analyzed using ordinal or binary logistic regression models. Furthermore, 2-sample Mendelian randomization analysis was performed to investigate the genetically predicted effect of cystatin C on CSVD.

RESULTS:

A total of 3061 participants were included in this study. The mean age of the participants was 61.2±6.7 years, and 1637 (53.5%) were women. Higher level of cystatin C was associated with an increased total CSVD burden and modified total CSVD burden (Q4 versus Q1: common odds ratio [OR], 1.30 [95% CI, 1.03–1.64] and 1.32 [95% CI, 1.01–1.73]) after adjustment for covariates. Further, compared with the first quartile of cystatin C, subjects in the last quartile had higher risk of lacunes (OR, 1.99 [95% CI, 1.05–3.76]), modified white matter hyperintensity burden (common OR, 1.42 [95% CI, 1.07–1.90]), and moderate-to-severe perivascular spaces (OR, 2.15 [95% CI, 1.29–3.59]) but not cerebral microbleeds. The Mendelian randomization analysis showed that a genetically predicted higher cystatin C level was associated with increased risk of lacunar stroke (OR, 1.16 [95% CI, 1.06–1.27]).

CONCLUSIONS:

In this community-based study, we found a possible association between cystatin C and CSVD, especially for lacunes, that was independent of estimated glomerular filtration rate.

The Relationship Between Renal Function and Imaging Markers and Total Burden of Cerebral Small Vessel Disease

BACKGROUND

Previous studies demonstrating the association between renal functions and cerebral small vessel diseases have usually focused on white matter hyperintensity in the general population or lacunar stroke patients. This study aimed to investigate the effects of renal function on imaging markers of cerebral small vessel disease and etiologic subtypes of stroke in patients with acute ischemic stroke or transient ischemic attack.

MATERIALS AND METHODS

A total of 356 consecutive patients with acute ischemic stroke or transient ischemic attack who were admitted to the Stroke Unit and underwent brain magnetic resonance imaging were evaluated. Demographic data, vascular risk factors, stroke etiology, estimated glomerular filtration rate and severity of cerebral small vessel disease markers, and total cerebral small vessel disease burden were evaluated.

RESULTS

There was a significant inverse correlation between estimated glomerular filtration rate and total number of lacunes, periventricular and deep subcortical Fazekas scores, grade of enlarged perivascular spaces in the centrum semiovale, lobar and total cerebral microbleeds, and total cerebral small vessel disease burden. Impaired renal function was an independent risk factor for the presence of lacunes, deep cerebral microbleeds, and increased total burden. Renal function impairment and periventricular white matter hyperintensities were significantly associated with the etiologic subgroup of small vessel occlusion. The results were still significant after the exclusion of patients below 50 years of age.

CONCLUSION

Our results indicate that there is a relationship between renal function impairment and increased total burden, as well as acute ischemic stroke/transient ischemic attack due to small vessel occlusion.

Kidney Function Is Not Related to Brain Amyloid Burden on PET Imaging in The 90+ Study Cohort

Cognitive decline is common in chronic kidney disease (CKD). While the evidence of vascular cognitive impairment in this population is robust, the role of Alzheimer's pathology is unknown. We evaluated serum cystatin C-estimated glomerular filtration rate (eGFR), brain amyloid-β positron emission tomography (PET) imaging, and cognitive function in 166 participants from The 90+ Study. Mean age was 93 years (range 90-107) and 101 (61%) were women; 107 participants had normal cognitive status while 59 participants had cognitive impairment no dementia (CIND) or dementia. Mean ± standard deviation cystatin C was 1.59 ± 0.54 mg/L with eGFR 40.7 ± 18.7 ml/min/1.73m2. Higher amyloid-β burden was associated with dementia, but not with age, diabetes, hypertension, or cardiovascular disease. We found no association between brain amyloid-β burden and cystatin C eGFR. We previously reported that kidney function was associated with cognition and cerebral microbleeds in the same cohort of oldest-old adults (90+ years old). Collectively, these findings suggest that microvascular rather than Alzheimer's pathology drives CKD-associated cognitive dysfunction in this population.

Is microvascular dysfunction a systemic disorder with common biomarkers found in the heart, brain, and kidneys? - A scoping review

Although microvascular dysfunction (MVD) has been well characterized in individual organs as different disease entities, clinical evidence is mounting in support of an underlying systemic process. To address this hypothesis, we systematically searched PubMed and Medline for studies in adults published between 2014 and 2019 that measured blood biomarkers of MVD in three vital organs i.e. brain, heart, and the kidney. Of the 9706 unique articles 321 met the criteria, reporting 49 biomarkers of which 16 were common to the three organs. Endothelial dysfunction, inflammation including reactive oxidation, immune activation, and coagulation were the commonly recognized pathways. Triglyceride, C-reactive protein, Cystatin C, homocysteine, uric acid, IL-6, NT-proBNP, thrombomodulin, von Willebrand Factor, and uric acid were increased in MVD of all three organs. In contrast, vitamin D was decreased. Adiponectin, asymmetric dimethylarginine, total cholesterol, high-density and low-density cholesterol were found to be variably increased or decreased in studies. We review the pathways underlying MVD in the three organs and summarize evidence supporting its systemic nature. This scoping review informs clinicians and researchers in the multi-system manifestation of MVD. Future work should focus on longitudinal investigations to evaluate the multi-system involvement of this disease.

Mechanisms of Cerebral Microbleeds

Cerebral microbleeds (CMB) are a common MRI finding, representing underlying cerebral microhemorrhages (CMH). The etiology of CMB and microhemorrhages is obscure. We conducted a pathological investigation of CMH, combining standard and immunohistological analyses of postmortem human brains. We analyzed 5 brain regions (middle frontal gyrus, occipital pole, rostral cingulate cortex, caudal cingulate cortex, and basal ganglia) of 76 brain bank subjects (mean age ± SE 90 ± 1.4 years). Prussian blue positivity, used as an index of CMH, was subjected to quantitative analysis for all 5 brain regions. Brains from the top and bottom quartiles (n = 19 each) were compared for quantitative immunohistological findings of smooth muscle actin, claudin-5, and fibrinogen, and for Sclerosis Index (SI) (a measure of arteriolar remodeling). Brains in the top quartile (i.e. with most extensive CMH) had significantly higher SI in the 5 brain regions combined (0.379 ± 0.007 vs 0.355 ± 0.008; p < 0.05). These findings indicate significant coexistence of arteriolar remodeling with CMH. While these findings provide clues to mechanisms of microhemorrhage development, further studies of experimental neuropathology are needed to determine causal relationships.

Cystatin C promotes cognitive dysfunction in rats with cerebral microbleeds by inhibiting the ERK/synapsin Ia/Ib pathway

Although higher serum level of cystatin C (CysC) was observed in patients with cerebral microbleeds, its associated role in the disease has not been elucidated. In this work, a rat model of cerebral microbleeds was created with the aim of investigating effects of CysC on cognitive function in rats with cerebral microbleeds and the underlying mechanism. Serum samples of patients with cerebral microbleeds and healthy people of the same age were collected. Levels of cystatin C expression in these samples were measured using CysC kits. Moreover, 48 spontaneously hypertensive rats (SHRs) bred under specific pathogen-free (SPF) conditions were randomly divided into 4 groups: sham surgery control group (sham), model group (CMB), model + empty vector control group (CMB + vehicle), and model + cystatin C overexpression group (CMB + CysC). Expression levels of CysC in hippocampus of rats in each group were measured by western blot analysis. The Y-maze was used to evaluate cognitive function of rats. Hippocampal long-term potentiation (LTP) in rats was assessed by the electrophysiological assay. Alterations in levels of p-ERK1/2 and p-synapsin Ia/b proteins associated with cognitive function were identified by western blot analysis. The serum levels of CysC in patients with cerebral microbleeds were significantly upregulated (P<0.001). After injection of CysC, its expression levels in rat hippocampus were significantly increased (P<0.001), which enhanced the decline in learning and memory function, as well as the decrease of LTP in the rat model of cerebral microbleeds (P<0.001). Western blot results showed that injection of CysC further reduced the levels of p-ERK1/2 and p-synapsin Ia/b in the rat model of microbleeds (P<0.001). CysC was up regulated in serum of patients with cerebral microbleeds. It promoted cognitive dysfunction in rats with microbleeds by inhibiting ERK/synapsin Ia/Ib pathway.

Use of anticoagulant therapy and cerebral microbleeds: a systematic review and meta-analysis

BACKGROUND

Anticoagulant therapy increases the risk that cerebral microbleeds (CMBs) progress to intracerebral hemorrhage, but whether the therapy increases risk of CMB occurrence is unclear. We performed a systematic review and meta-analysis to investigate the potential association between anticoagulant use and CMB occurrence in stroke and stroke-free individuals.

METHODS

We searched observational studies in PubMed, Ovid EMBASE, and Cochrane Library from their inception until September 2019. We calculated the pooled odds ratio (OR) and 95% confidence interval (CI) for the prevalence and incidence of CMBs in anticoagulant users relative to non-anticoagulant users.

RESULTS

Forty-seven studies with 25,245 participants were included. The pooled analysis showed that anticoagulant use was associated with CMB prevalence (OR 1.54, 95% CI 1.26-1.88). The association was observed in subgroups stratified by type of participants: stroke-free, OR 1.86, 95% CI 1.25-2.77; ischemic stroke/transient ischemic attack, OR 1.33, 95% CI 1.06-1.67; and intracerebral hemorrhage, OR 2.26, 95% CI 1.06-4.83. Anticoagulant use was associated with increased prevalence of strictly lobar CMBs (OR 1.68, 95% CI 1.22-2.32) but not deep/infratentorial CMBs. Warfarin was associated with increased CMB prevalence (OR 1.64, 95% CI 1.23-2.18), but novel oral anticoagulants were not. Anticoagulant users showed higher incidence of CMBs during long-term follow-up (OR 1.72, 95% CI 1.22-2.44).

CONCLUSION

Anticoagulant use is associated with higher prevalence and incidence of CMBs. This association appears to depend on location of CMBs and type of anticoagulants. More longitudinal investigations with adjustment for confounders are required to establish the causality.

Characteristics of Cerebral Microbleeds

Cerebral microbleeds (CMBs) are increasingly recognized neuroimaging findings, occurring with cerebrovascular disease, dementia, and aging. CMBs are associated with subsequent hemorrhagic and ischemic stroke, and also with an increased risk of cognitive deterioration and dementia. They occur in the setting of impaired small vessel integrity due to hypertension or cerebral amyloid angiopathy. This review summarizes the concepts, cause or risk factors, histopathological mechanisms, and clinical consequences of CMBs.

Association of Renal Dysfunction With Remote Diffusion-Weighted Imaging Lesions and Total Burden of Cerebral Small Vessel Disease in Patients With Primary Intracerebral Hemorrhage

Objective: Remote diffusion-weighted imaging (DWI) lesions (R-DWIL) found in intracerebral hemorrhage (ICH) patients are considered as an additional marker of cerebral small vessel disease (cSVD). This study aimed to investigate the association of renal dysfunction and R-DWIL, as well as the total burden of cSVD on magnetic resonance imaging among patients with primary ICH. Methods: One hundred and twenty-six consecutive patients were prospectively enrolled. R-DWIL on DWI, as well as other imaging markers of cSVD, including lacunes, white matter lesions, cerebral microbleeds, and enlarged perivascular spaces were rated using validated scales. Renal dysfunction was evaluated either by reduced estimated glomerular filtration rate (eGFR) or the presence of proteinuria or increased cystatin C. Results: After adjustments for potential confounders by logistic regression, impaired eGFR [odds ratio (OR) 6.00, 95% confidence interval (CI) 1.73-20.78], proteinuria (OR 3.07, 95% CI 1.25-7.54) and increased cystatin C (OR 2.73, 95% CI 1.11-6.72) were correlated with presence of R-DWIL. A similar association was also found between cystatin C levels (OR 3.16, 95% CI 1.39-7.19), proteinuria (OR 2.79, 95% CI 1.34-5.83) and the comprehensive cSVD burden. Conclusions: Renal dysfunction are associated with the presence of R-DWIL, and total burden of cSVD in patients with primary ICH.

Associations Between Left Ventricular Dysfunction and Brain Structure and Function: Findings From the SABRE (Southall and Brent Revisited) Study

Background

Subclinical left ventricular (LV) dysfunction has been inconsistently associated with early cognitive impairment, and mechanistic pathways have been poorly considered. We investigated the cross‐sectional relationship between LV dysfunction and structural/functional measures of the brain and explored the role of potential mechanisms.

Method and Results

A total of 1338 individuals (69±6 years) from the Southall and Brent Revisited study underwent echocardiography for systolic (tissue Doppler imaging peak systolic wave) and diastolic (left atrial diameter) assessment. Cognitive function was assessed and total and hippocampal brain volumes were measured by magnetic resonance imaging. Global LV function was assessed by circulating N‐terminal pro–brain natriuretic peptide. The role of potential mechanistic pathways of arterial stiffness, atherosclerosis, microvascular disease, and inflammation were explored. After adjusting for age, sex, and ethnicity, lower systolic function was associated with lower total brain (beta±standard error, 14.9±3.2 cm³; P<0.0001) and hippocampal volumes (0.05±0.02 cm³, P=0.01). Reduced diastolic function was associated with poorer working memory (−0.21±0.07, P=0.004) and fluency scores (−0.18±0.08, P=0.02). Reduced global LV function was associated with smaller hippocampal volume (−0.10±0.03 cm³, P=0.004) and adverse visual memory (−0.076±0.03, P=0.02) and processing speed (0.063±0.02, P=0.006) scores. Separate adjustment for concomitant cardiovascular risk factors attenuated associations with hippocampal volume and fluency only. Further adjustment for the alternative pathways of microvascular disease or arterial stiffness attenuated the relationship between global LV function and visual memory.

Conclusions

In a community‐based sample of older people, measures of LV function were associated with structural/functional measures of the brain. These associations were not wholly explained by concomitant risk factors or potential mechanistic pathways.

Association between serum cystatin C levels and the severity or potential risk factors of acute ischemic stroke

OBJECTIVE

We sought to investigate whether serum cystatin C levels are correlated with either stroke severity or with potential risk factors of acute ischemic stroke.

METHODS

171 patients with acute ischemic stroke and 99 control subjects with minor, unrelated diseases with stroke were included in this retrospective study. Serum cystatin C levels were determined in all subjects. Serum concentrations of several vascular risk factors in stoke patients were determined by biochemical assays. The severity of strokes was scored via the National Institutes of Health Stroke Scale (NIHSS).

RESULTS

Serum cystatin C levels were significantly increased in patients with acute ischemic stroke compared with control subjects (1.26 ± 0.34 mg/L vs. 0.78 ± 0.24 mg/L, p < 0.001).When analyzed in quartiles of serum cystatin C levels, concentrations were low (<0.75 mM) for 5 stroke patients (2.92%), intermediate (0.75-1 mM) for 42 patients (24.56%), high (1-1.25 mM) for 45 patients (26.32%), and very high (>1.25 mM) for 79 patients (46.20%). However, serum cystatin C levels were not correlated with NIHSS scores, serum total cholesterol, high-density lipoprotein, low-density lipoprotein, apolipoprotein a, or apolipoprotein b levels. Further, serum cystatin C concentrations in stroke patients were not correlated with the presence of intracranial arterial stenosis, hypertension, or diabetes.

CONCLUSION

Our study suggests that there is a close relationship between cystatin C and acute ischemic stroke, independently of conventional risk factors. But the levels of cystatin C are not correlated with the stroke severity.

Cystatin C is a useful predictor of early neurological deterioration following ischaemic stroke in elderly patients with normal renal function

Introduction

Cystatin C has been suggested as a sensitive marker of renal function. A high level of cystatin C is related to cardiovascular disease and stroke in elderly patients. We investigated the relationship between levels of cystatin C and early neurological deterioration with acute ischaemic stroke in elderly patients without chronic kidney disease.

Patients and methods

We evaluated a total of 771 elderly patients (mean age, 72.2; male, 59.0%) without chronic kidney disease who were admitted following acute ischaemic stroke between March 2010 and January 2015. The patients were divided into four groups based on the quartiles of serum cystatin C values. Early neurological deterioration was defined as an increase of ≥2 points from the baseline National Institutes of Health Stroke Scale score during the 7 days following onset. We compared the clinical characteristics and cystatin C concentrations between patients with and without early neurological deterioration.

Results

Eighty-six patients (11.2%) experienced early neurological deterioration. The percentage values of the higher (third and fourth) quartiles were significantly higher in the early neurological deterioration group (30.2% vs. 24.4% and 34.9% vs. 23.8%, P = 0.002). After adjustment for covariates, higher cystatin C levels were independently associated with a higher risk of early neurological deterioration: odds ratio (95% confidence interval) for second quartile 1.59 (0.70-3.58), third quartile 2.75 (1.25-6.04), fourth quartile 3.12 (1.36-7.16); P for trend 0.026.

Discussion and conclusions

This study demonstrated that cystatin C concentrations in elderly patients without chronic kidney disease were associated with early neurological deterioration following acute stroke. This suggests that cystatin C level could be a useful predictor for early neurological deterioration following acute stroke.

Association Between Serum Cystatin C Level and Total Magnetic Resonance Imaging Burden of Cerebral Small Vessel Disease in Patients With Acute Lacunar Stroke

OBJECTIVE

Chronic kidney disease (CKD) is associated with cerebral small vessel disease (cSVD). However, the relationship between serum cystatin C (CysC) level, a highly sensitive marker of impaired kidney function, and cSVD has not been fully understood. This study aimed to investigate the association between serum CysC level and total burden of cSVD on magnetic resonance imaging (MRI) in patients with acute lacunar stroke.

MATERIALS AND METHODS

A total of 210 patients with first-ever acute lacunar stroke occurring within 1 week after onset were included in this study. Serum CysC level, decreased estimated glomerular filtration rate (eGFR), and proteinuria were used to evaluate kidney function. The combined effect of the markers of cSVD on MRI, including lacunar, white matter lesions, cerebral microbleeds, and enlarged perivascular spaces, were used to evaluate the comprehensive cSVD burden.

RESULTS

There is a positive association between total cSVD burden and hypertension, low eGFR level, and serum CysC level. After adjustments for potential confounders by ordinal logistic regression, elevated levels of CysC as well as impaired eGFR and the presence of proteinuria were correlated with the burden of total cSVD (odds ratio [OR] 2.633, 95% confidence interval [CI] 1.284-5.403; OR 2.442, 95% CI 1.213-4.918; and OR 2.151, 95% CI 1.162-3.983, respectively).

CONCLUSIONS

The elevated level of serum CysC is associated with the total burden of cSVD in patients with acute lacunar stroke independent of conventional risk factors.

Common Impact of Chronic Kidney Disease and Brain Microhemorrhages on Cerebral Aβ Pathology in SHRSP

While chronic kidney disease seems to be an independent risk factor for cognitive decline, its impact on cerebral amyloid-β (Aβ) depositions, one hallmark of Alzheimer's Disease (AD) pathology, has not been investigated. Utilizing 80 male nontransgenic spontaneously hypertensive stroke prone rats (SHRSP) at various ages (12 to 44 weeks), tubulointerstitial renal damage, prevalence of cerebral microhemorrhages and Aβ accumulations were quantified. Using age-adjusted general linear models we investigated the main and interaction effects of renal damage and cerebral microhemorrhages on cerebral Aβ load. In addition, using post mortem human brain tissue of 16 stroke patients we examined the co-localization of perivascular Aβ deposits and small vessel wall damage. Statistical models revealed an age-independent main effect of tubulointerstitial kidney damage on brain Aβ accumulations, which was reinforced by the consecutive presence of cerebral microhemorrhages. Moreover, cerebral microhemorrhages independently predicted brain Aβ burden in SHRSP. In up to 69% of all human cases perivascular Aβ deposits were detected in the direct vicinity of small vessel wall damage. Our results support the associations between vascular pathology and Aβ deposition, and demonstrate a relationship between chronic kidney disease and cerebral Aβ pathology. Hence, our data suggest that prevention of chronic renal damage may reduce cerebral Aβ pathology.

Decreased kidney function relates to progression of cerebral microbleeds in lacunar stroke patients

BACKGROUND

It is hypothesized that impaired kidney function and cerebral microbleeds represent microvascular damage in different organs. Several cross-sectional studies found impaired kidney function to be associated with the presence of cerebral microbleeds.

AIM

To further confirm the association between both small vessel diseases, we aimed to determine whether kidney function is related to progression of cerebral microbleeds in a longitudinal study design.

METHODS

In 89 lacunar stroke patients, baseline brain magnetic resonance imaging (including gradient-echo images), baseline estimated glomerular filtration rate (eGFR), blood pressure measurements, and follow-up brain magnetic resonance imaging after two years were available. Presence of cerebral microbleeds on baseline and follow-up magnetic resonance imaging was scored visually. Cerebral microbleeds progression was defined as the presence of any new microbleed on follow-up magnetic resonance imaging. The association between cerebral microbleeds progression (dependent variable) and eGFR (independent variable) was assessed by logistic regression analysis.

RESULTS

Cerebral microbleeds progression was present in 17 patients (19.1%). Lower eGFR was associated with cerebral microbleeds progression (OR 1.55 per 10 ml/min/1.73 m(2) decrease, 95% CI 1.05-2.30, with correction for sex and age). After additional correction for baseline presence of cerebral microbleeds or correction for cardiovascular risk factors, including blood pressure, this result remained significant.

CONCLUSIONS

In this longitudinal study, we found an independent association between lower eGFR and cerebral microbleeds progression. Cerebral microbleeds and impaired kidney function are both seen as manifestations of microvascular organ damage and our findings further strengthen the association between both small vessel pathologies and also the assumption that small vessel disease could be considered a multisystem disorder.

Solving the Measurement Problem and then Steppin' Out over the Line Riding the Rarest Italian: Crossing the Streams to Retrieve Stable Bioactivity in Majorana Bound States of Dialy zed Human Platelet Lysates

Exhaustive dialysis (ED) of lysed human platelets against dilute HCl yields stable angiogenic activity. Dialysis against a constrained external volume, with subsequent relaxation of the separation upon opening the dialysis bag, produces material able to maintain phenotypes and viability of human cells in culture better than ED material. Significant graded changes in MTT viability measurement tracked with external volume. The presence of elements smaller than the MW cutoff, capable of setting up cycling currents initiated by oriented flow of HCl across the membrane, suggests that maturation of bioactivity occurred through establishment of a novel type of geometric phase. These information-rich bound states fit recent descriptions of topological order and Majorana fermions, suggesting relevance in testing Penrose and Hameroff's theory of Orchestrated Objective Reduction, under conditions more general, and on finer scales, than those dependent on tubulin protein. The Berry curvature appears to be a good tool for building a general field theory of physiologic stress dependent on the quantum Hall effect. A new form of geometric phase, and an associated "geometric" quantum Hall effect underlying memory retrieval, dependent on the rate of path traversal and reduction from more than two initial field influences is described.

Kidney function and cerebral small vessel disease in the general population

BACKGROUND

Anatomic and hemodynamic similarities between renal and cerebral vessels suggest a tight link between kidney disease and brain disease. Although several distinct markers are used to identify subclinical kidney and brain disease, a comprehensive assessment of how these markers link damage at both end organs is lacking.

AIM

To investigate whether measures of kidney function were associated with cerebral small vessel disease on MRI.

METHODS

In 2526 participants of the population-based Rotterdam Study, we measured urinary albumin-to-creatinine ratio, and estimated glomerular filtration rate based on serum creatinine and cystatin C. All participants underwent brain magnetic resonance imaging. We assessed presence of cerebral small vessel disease by calculating white matter lesion volumes and rating the presence of lacunes and cerebral microbleeds. We used multivariable linear and logistic regression to investigate the association between kidney function and cerebral small vessel disease.

RESULTS

Worse kidney function was consistently associated with a larger white matter lesion volume (mean difference per standard deviation increase in albumin-to-creatinine ratio: 0.09, 95% confidence interval 0.05; 0.12; per standard deviation decrease in creatinine-based estimated glomerular filtration rate: -0.04, 95% confidence interval -0.08;-0.01, and per standard deviation decrease in cystatin C-based estimated glomerular filtration rate: -0.09, 95% confidence interval -0.13;-0.05). Persons with higher albumin-to-creatinine ratio or lower cystatin C-based estimated glomerular filtration rate levels had a higher prevalence of lacunes (odds ratio per standard deviation increase in albumin-to-creatinine ratio: 1.24, 95% confidence interval 1.07; 1.43). Only participants in the highest quartile of albumin-to-creatinine ratio had a higher frequency of microbleeds compared to the lowest quartile.

CONCLUSIONS

Worse kidney function is associated with cerebral small vessel disease. Of all measures of kidney function, in particular albumin-to-creatinine ratio is related to cerebral small vessel disease.