Mechanisms of cognitive dysfunction in CKD

The alterations of sleep and frontal functions in chronic hemodialysis: Pathogenesis and therapeutic perspectives

Chronic kidney disease (CKD) and, in particular, chronic haemodialysis (HD) patients have a high risk of developing sleep disorders and executive dysfunction. Sleep disorders have a prevalence of 75 % in the haemodialysed population and several causes are behind their occurrence: sympatho-vagal imbalances, low melatonin production, vitamin D deficiency, altered cerebral haemodynamics and haemodialysis-induced vascular stress. Executive dysfunction affects about 55 % of haemodialysis patients. The causes can be ascribed to dysfunctions of the frontal lobes. HD patients show frontal brain atrophy and reduced brain activity and connectivity of several frontal and prefrontal areas. Sleep quality also has a significant impact on executive functions; inefficient and fragmented sleep reduces the efficiency of executive functions and increases the risk of dementia. Sleep deprivation also alters the connectivity and structure of several frontal areas. Thus, sleep and executive functions seem to be closely linked. Multidisciplinary care of patients with CKD and in HD appears essential to structure preventive interventions, pharmacological and non-pharmacological treatments that can improve sleep quality, preserve the integrity of executive functions and improve their quality of life.

Low preoperative estimated glomerular filtration rate level is a risk factor for postoperative cognitive dysfunction in elderly undergoing elective total hip replacement: a prospective observational study

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a postoperative complication of the central nervous system, especially in elderly patients. Growing evidence shows a close relationship between the kidney and cognition. This study aimed to evaluate the relationship between the subsequent risk of POCD and indicators related to the kidney.

METHODS

A total of 93 eligible patients (≥65 years old) undergoing elective total hip replacement were enrolled. Before and 1 day after surgery, blood samples were collected from enrolled patients. Mini-Mental State Examination and Montreal Cognitive Assessment were conducted 1 day before surgery and 1 week after surgery or at discharge. The receiver operating characteristic curve was used to examine the predictive value of the estimated glomerular filtration rate (eGFR) for POCD. Univariate and multiple logistic regression models were used to analyze the risk factors of POCD.

RESULTS

Thirty patients (32.26%) were assessed for POCD 1 week after surgery. The preoperative eGFR level in the POCD group was significantly lower than in the non-POCD group (P < 0.001). The area under the curve of eGFR was 0.739 (95% CI, 0.630-0.848; P < 0.001). The multivariable logistic regression analysis results showed that preoperative eGFR was independently associated with POCD (odds ratio = 0.965, 95% CI = 0.935-0.996, P = 0.028) after adjustment for mixed factors.

CONCLUSION

Low eGFR is associated with an increased risk of POCD in patients undergoing elective total hip replacement surgery. Low eGFR is an effective predictor of incident POCD.

Irisin Alleviates Cognitive Impairment by Inhibiting AhR/NF-κB-NLRP3-Mediated Pyroptosis of Hippocampal Neurons in Chronic Kidney Disease

Introduction: Cognitive impairment is a vital complication of chronic kidney disease (CKD). The effect of irisin on CKD-induced cognitive impairment remains unclear. In the present study, we aimed to investigate the role of Irisin in mitigating cognitive impairment and explore the underlying mechanisms in CKD. Methods: A CKD mice model was established by adenine. Cognitive function was assessed via the novel object recognition (NOR). Interleukin-1β (IL-1β) levels were measured by enzyme-linked immunosorbent assay (ELISA), while pyroptosis-related protein expression was analyzed using western blotting. Results: Our data showed an upregulation of cell pyroptosis in hippocampus tissues of CKD mice, accompanied by significant cognitive impairment. Pyroptosis and cognitive impairment was both improved by Irisin treatment in vivo. Additionally, irisin markedly downregulated pyroptosis levels through aryl hydrocarbon receptor (AhR)/NF-κB p65 signaling in HT-22 cells pretreated with indoxyl sulfate (IS). In vitro experiments further confirmed that pyroptosis was inhibited by AhR and NF-κB p65 inhibitors. Conclusions: We first demonstrated that irisin alleviated cognitive impairment by inhibiting AhR/NF-κB-NLRP3-mediated pyroptosis of hippocampal neurons in CKD. Overall, irisin may have the potential to serve as a critical antipyroptotic agent for improving CKD-induced cognitive impairment.

Exploring the Neuroprotective Effects of Rufinamide in a Streptozotocin-Induced Dementia Model

Due to the complex pathophysiology of AD (Alzheimer's Disease), there are currently no effective clinical treatments available, except for acetylcholinesterase inhibitors. However, CREB (cyclic AMP-responsive element binding protein) has been identified as the critical factor for the transcription in memory formation. Understanding the effect of potential drugs on the CREB pathway could lead to the development of new therapeutic molecules. Rufinamide has shown promise in improving memory in animal models, and these effects may be associated with modulation of the CREB pathway, however, this has not been previously reported. Thus, the present study aimed to determine the involvement of the CREB pathway in the cognitive improvement effects of rufinamide in STZ (streptozotocin) induced mouse model of dementia. Administration of STZ [3 mg/kg, i.c.v. (intracerebroventricular) bilaterally] significantly impaired cognitive performance in step-down passive avoidance and Morris water maze tests in animals, reduced brain endogenous antioxidant levels (GSH, superoxide dismutase, and catalase), and increased marker of brain oxidative stress [TBARS (thiobarbituric acid reactive substances)] and inflammation [IL-1β (Interleukin-1 beta), IL-6 (Interleukin-6), TNF-α (Tumor necrosis factor alpha) and NF-κB (Nuclear factor kappa B)], along with neurodegeneration. These effects were markedly reversed by rufinamide (50 and 100 mg/kg) when administered to STZ animals. However, the pre-treatment with the CREB inhibitor (666-15) in STZ and rufinamide-administered animals neutralized the beneficial influence of rufinamide. Our data suggest that rufinamide, acting via CREB signaling, reduced oxidative stress and inflammatory markers while elevating anti-oxidant levels. Our study has established that rufinamide may act through CREB signaling in an investigational AD model, which could be crucial for developing new treatments beneficial in progressive neurological disorders.

Altered spontaneous brain activity in patients with progressive-stage and end-stage chronic kidney disease: insights from dALFF analysis

Chronic kidney disease (CKD) is a worldwide public health problem. Its association with cognitive impairment has attracted widespread attention in the world. However, the neuropathological mechanisms underlying kidney-brain interactions in CKD remain unclear. Using the dynamic amplitude of low-frequency fluctuations (dALFF) technique, 21 patients with progressive-stage CKD (CKD stages 3-4), 22 patients with end-stage CKD (CKD stage 5, ESKD), and 23 healthy volunteers (HCs) were enrolled to explore the brain regions with dALFF abnormalities in the progressive-stage and end-stage CKD. We used biased correlation analyses to explore the relationship between dALFF values and clinical indicators in patients with progressive-stage and end-stage CKD. Patients with both progressive-stage CKD (stages 3-4) and ESKD had abnormal dALFF values in the right parahippocampus, right inferior temporal gyrus, and left cuneus compared with HCs. In addition, abnormal dALFF were present in the left fusiform gyrus, insula and hippocampus in patients with progressive-stage CKD and in the left inferior temporal gyrus in patients with ESKD. Biased correlation analysis showed that dALFF values in the right parahippocampus, left fusiform gyrus and left insula were positively correlated with serum creatinine concentrations in patients with progressive-stage CKD and that dALFF values in the left inferior temporal gyrus were negatively correlated with MoCA scores in patients with ESKD. Our findings highlight the variability of neuroimaging changes between different stages of CKD and provide new insights and research directions for an in-depth exploration of the neuropathological mechanisms of renal-brain interactions.

Prevalence and risk factors of cognitive frailty in patients with cardiovascular disease: A hospital-based cross-sectional study

The prevalence of the cognitive frailty is increasing in China. Screening for this condition is crucial for its early detection, prevention, and treatment. This study was designed to explore the incidence of cognitive frailty among hospitalized elderly patients suffering from cardiovascular disease. It also aimed to analyze the factors influencing its occurrence, thereby providing substantial evidence for the development of early prevention and intervention strategies. From March 2022 to October 2023, under cardiovascular care program, the cardiovascular patients (n = 1190) were subjected to standardized questionnaires to collect demographical characteristics. Also, nutritional and psychosocial assessments tests were performed for the enrolled patients. Multivariate logistic regression analysis was used to evaluate factors associated with cognitive frailty. A total of 1190 (755 males and 435 females) were included. The mean age was 73.36 ± 7.37 years. The prevalence of cognitive frailty in the study population was 33.9% (404/1190). The prevalence of cognitive frailty was 40.7% in men, 22.3% in women. In terms of specific cardiovascular diseases, the prevalence of cognitive frailty was 28.5% in coronary heart disease, 20.5% in arrhythmia, 36.8% in valvular disease, 53% in heart failure, and 13.7% in hypertension. The multivariable analysis showed that age (OR = 1.13, 95% CI: 1.10-1.15, P < .001), anxiety (OR = 1.01, 95% CI: 1.03-1.11, P = .001), female sex (OR = 1.83, 95% CI: 1.10-1.16, P < .001), education level (college and above, OR = 0.27, OR = 0.12-0.64, P = .003), polypharmacy (OR = 2.29, 95% CI: 1.62-3.23, P < .001), comorbidity (OR = 1.93 95% CI: 1.37-2.71, P < .010), region (rural, OR = 1.77, 95% CI: 1.36-2.30, P < .001), sarcopenia (OR = 1.60, 95% CI: 1.16-2.19, P = .004), and nutritional status (risk of malnutrition, OR = 1.66, 95% CI: 1.17-2.35, P = .004; malnutrition exists, OR = 3.24, 95% CI: 1.85-5.83, P < .001) were independently associated with cognitive frailty. The prevalence of cognitive frailty was 33.9% in hospitalized elderly cardiovascular patients in Guangzhou. heart failure, hypertension, age, anxiety, female sex, education level, polypharmacy, comorbidity, region, sarcopenia, and nutritional status were independent risk factors for cognitive frailty.

New insights into mechanisms underlying cognitive impairment in chronic kidney disease

Chronic kidney disease (CKD) is associated with an increased risk of cognitive impairment. Patients with CKD display an increased permeability of the blood-brain barrier. Zimmermann et al. highlighted the implication of potassium efflux in the microglia and its activation, the activation of the interleukin-1b/interleukin-1R pathway, linked to blood-brain barrier permeability and cognitive impairment in CKD. Along with uremic toxicity, this study provides new solid insights about pathophysiological mechanisms of cognitive impairment in CKD, and potential therapeutic targets.

The Clock Drawing Task reveals executive dysfunction in the dialysis population - an underrecognized and underestimated problem

AIM OF THE STUDY

The study aimed to assess the prevalence of executive function impairment among patients with chronic kidney disease (CKD) undergoing dialysis, with no subjective cognitive problems and with normal global cognition on the Mini-Mental State Examination (MMSE). We also investigated the relationship between cardiovascular risk factors and cognitive test results.

RATIONALE FOR THE STUDY

Patients with CKD, including those undergoing renal replacement therapy, are at a higher risk of developing cognitive impairment (CI) than the general population. Recent research has shown CI to be a growing problem among CKD patients worldwide. Yet, it remains underdiagnosed, even though it may significantly influence the lives of patients.

MATERIALS AND METHODS

In this cross-sectional, prospective study, 58 dialysis patients with no cognitive decline on the MMSE screening were assessed for executive function impairment using the Executive Clock-Drawing Task (CLOX). Moreover, past medical history, demographic data, and laboratory test results were collected.

RESULTS

The mean patient age was 59.47 ± 14.98 years, and the mean duration of dialysis was 45.93 ± 48.49 months. The prevalence of executive function impairment amounted to 8.6%. Moreover, remarkably similar pattern of clock drawing was observed, with numbers written outside the clock face in the CLOX1 test.

CONCLUSIONS

Executive dysfunctions in dialysis patients may manifest itself before the onset of global cognitive impairment. There appear to be a deficit in the spatial domain as well. Better education may play a protective role.

Association between serum neurofilament light chain levels and chronic kidney disease: a cross-sectional population-based study from the National Health and Nutrition Examination Survey (2013-2014 cycle)

BACKGROUND

The relationships of serum neurofilament light chain (NfL) levels with chronic kidney disease (CKD) and renal function indicators remain controversial, and comprehensive studies with large sample sizes are lacking.

METHODS

In total, 2,051 participants aged 20 to 75 years were identified from the National Health and Nutrition Examination Survey (2013-2014 cycle). Logistic regression models were used to assess the associations between serum NfL levels and CKD, whereas multivariate linear models were used to investigate the relationships between serum NfL levels and two kidney function indicators, namely, estimated glomerular filtration rate (eGFR) and urinary albumin-creatinine ratio (UACR). Adjustments were made to account for potential confounding variables in the analysis. Subgroup analyses stratified by age and sex were conducted. When sNfL is incorporated into the model as continuous variables, a log transformation is applied.

RESULTS

The present study included a cohort of 2,051 individuals ranging in age from 20 to 75 years. After covariate adjustment, multivariable logistic regression revealed a significant association between high serum NfL levels and an increased prevalence of CKD (OR 1.60; 95% CI 1.40-1.82; p < 0.0001), which remained significant when analyzed by quartiles (p for trend <0.0001). There was a statistically significant inverse correlation between the serum NfL level and the eGFR (β=-6.34; 95% CI -8.32 to -4.37; p < 0.0001), as well as a positive correlation between the serum NfL level and the UACR (β = 84.67; 95% CI 19.52-149.83; p < 0.0001). Furthermore, when stratified by age, there were significant interactions of serum NfL levels with CKD, the eGFR, and the UACR (p for interaction = 0.008, 0.016, and 0.020, respectively).

CONCLUSION

Serum NfL levels are positively associated with the prevalence of CKD and the UACR but negatively correlated with the eGFR, particularly in older patients.

Association of dementia with impaired kidney function and plasma biomarkers: A population-based study

BACKGROUND AND PURPOSE

Emerging evidence has linked impaired kidney function with dementia in older adults, but the neuropathological pathways underlying their association remain poorly understood. We sought to examine the relationships of kidney function with dementia and plasma biomarkers in a Chinese rural population.

METHODS

This population-based study used data from the baseline examination of the Multimodal Interventions to Delay Dementia and Disability in rural China (MIND-China) cohort (March-September 2018; n = 5715). Kidney function was assessed using estimated glomerular filtration rate (eGFR) based on serum creatinine level. Dementia, Alzheimer's disease (AD) and vascular dementia (VaD) were diagnosed according to the international criteria. Plasma biomarkers were measured using the SIMOA platform in a subsample (n = 1446). Data were analyzed using logistic, general linear, and mediation models.

RESULTS

Of the 5715 participants, 306 were diagnosed with dementia, including 195 with AD and 100 with VaD. Impaired kidney function (eGFR <60 vs. ≥90 mL/min/1.73 m2) was associated with multivariable-adjusted odds ratios of 2.24 (95% confidence interval [CI] 1.44-3.46) for all-cause dementia, 1.85 (1.07-3.18) for AD, and 2.49 (1.16-5.22) for VaD. In the biomarker subsample, impaired kidney function was significantly associated with higher plasma amyloid-β (Aβ)40 (β-coefficient = 54.36, 95% CI 43.34-65.39), Aβ42 (β-coefficient = 3.14, 95% CI 2.42-3.86), neurofilament light chain (β-coefficient = 10.62, 95% CI 5.62-15.62), and total tau (β-coefficient = 0.68, 95% CI 0.44-0.91), and a lower Aβ42/Aβ40 ratio (β-coefficient = -4.11, 95% CI -8.08 to -0.14). The mediation analysis showed that plasma total tau significantly mediated 21.76% of the association between impaired kidney function and AD (p < 0.05).

CONCLUSION

Impaired kidney function is associated with dementia and plasma biomarkers among rural-dwelling older Chinese adults, and the association with AD is partly mediated by plasma biomarkers for neurodegeneration.

The relationship between thiamin, folic acid and cognitive function in a rat model of uremia

End-stage renal disease is a worldwide health burden, but the pathogenesis of uremia-associated cognitive impairment (CI) is poorly recognized. We hypothesized that uremia brings about deficiency of thiamin and folic acid and causes CI by inducing oxidative stress. Therefore, 24 Sprague-Dawley rats were randomly divided into two groups: a 5/6 nephrectomy group (n = 12) and a sham-operated group (n = 12). The Morris water maze was used to assess the cognitive function eight weeks post-surgery, and serum levels of thiamin, folic acid and homocysteine were detected subsequently. Brain and kidney tissues were collected for pathological examination and 8-Hydroxy-2'-deoxyguanosine (8-OHdG) immunochemistry staining. Results showed that the escape latency on training days 1-2 was longer, and the time in quadrant IV on experimental day 6 was significantly shorter in 5/6 nephrectomy group. Meanwhile, the uremic rats showed decreased thiamin, folic acid and increased homocysteine. We also found the time in quadrant IV was positively correlated with thiamin and folic acid level, while negatively correlated with the blood urea nitrogen and 8-OHdG positive cell proportion. Furthermore, in 5/6 nephrectomy group, the hippocampal neuron count was significantly reduced, and a greater proportion of 8-OHdG positive cells were detected. Pretreating LPS-stimulated rat microglial cells with thiamin or folic acid in vitro alleviated the inflammatory impairment in terms of cell viability and oxidative stress. In summary, we applied a uremic rat model and proved that uremia causes serum thiamin and folic acid deficiency, homocysteine elevation, along with neuron reduction and severe oxidative stress in hippocampus, finally leading to CI.

The mediating role of nutritional indicators in the association between estimated glomerular filtration rate and cognitive impairment in older adults

BACKGROUND

Cognitive impairment (CI) is common in older adults, especially those with renal dysfunction. We aimed to investigate the complex relationships among renal function, nutritional status, and CI in older people free from late chronic kidney disease (CKD) and severe CI.

METHODS

A study of older people (≥60 years old) with an estimated glomerular filtration rate (eGFR) of >30 mL/min/1.73 m2 and Montreal Cognitive Assessment (MoCA) scores of >10 (n = 237) was conducted at Beijing Tongren Hospital. Their eGFR was determined using the CKD-EPI-cr-Cysc equation. Cognitive function was evaluated with the MoCA. We tested the relationship between eGFR and MoCA scores using Spearman correlation analysis and multivariate logistic regression analysis. We then conducted a mediation analysis to figure out the mediating roles of nutritional indicators (Mini Nutritional Assessment-Short Form (MNA-SF) scores, albumin (ALB), and haemoglobin (HGB)) between the eGFR and MoCA scores.

RESULTS

The incidence of CI was 48.5% (115/237) in older people. Spearman correlation analysis revealed that the better the kidney function, the better the cognitive function (R = 0.297, P < 0.001). Multivariate logistic regression analysis revealed that eGFR decrease per 15 mL/min/1.73 m2 (OR: 1.415, 95% confidence interval: 1.055-1.896, P = 0.020) was related to CI after adjusting for age and sex. However, the eGFR was not associated with cognitive decline after adjusting for nutritional indicators, behavioural risk factors, other biomarkers, and chronic conditions, suggesting that eGFR is not independently associated with CI. Mediation analysis revealed that the MNA-SF scores (a*b = 0.006 (0.0002-0.012)) and HGB (a*b = 0.008 (0.001-0.017)) were mediating factors between the eGFR and MoCA scores.

CONCLUSIONS

A decline in renal function can directly lead to CI and can also exacerbate cognitive deficits through intermediary factors such as MNA-SF scores and HGB. Therefore, correcting anaemia and improving nutritional status are significantly important for enhancing cognitive function in older patients, especially those with renal dysfunction.

Predictors of academic delay post-pediatric kidney transplant in the USA

BACKGROUND

Pediatric patients with kidney failure often experience cognitive delays. However, academic delay (being more than one grade level below age-appropriate grade, or in special education) after pediatric kidney transplantation (KTx) has not been explored. We sought to identify patient characteristics associated with a higher risk of academic delay 1 year post-KTx.

METHODS

We used the United Network for Organ Sharing (UNOS) database to identify children aged 6-17 years who received a primary KTx between 2014 and 2021 and had a functioning graft 1 year after KTx. The primary outcome was the patient's academic progress at 1 year post-transplant. The secondary outcome was change in academic progress between transplant and 1-year follow-up: onset of new delay, resolution of pre-existing delay, persistence of delay, or no delay at either timepoint. Binomial and multinomial mixed effects logistic regression models were used to predict each outcome based on patient characteristics.

RESULTS

The study included 2197 patients, of whom 14% demonstrated academic delay at 1 year post-KTx, 4% demonstrated a new onset of academic delay, 5% demonstrated a resolution of academic delay, and 10% demonstrated persistent academic delay. Patients undergoing transplantation at a younger age, receiving a deceased donor kidney, experiencing longer waitlist times, and undergoing KTx for vascular or other disease indications for KTx were more likely to experience academic delays, including new-onset academic delays.

CONCLUSIONS

Academic delays are frequently reported among pediatric KTx recipients. Additional academic support may help resolving or preventing academic delay for at-risk subgroups of children undergoing KTx.

Association between serum magnesium levels and cognitive function in patients undergoing hemodialysis

BACKGROUND

The relationship between chronic kidney disease-mineral and bone disorder (CKD-MBD) and cognitive function remains largely unknown. This cross-sectional study aimed to explore the association between CKD-MBD and cognitive function in patients on hemodialysis.

METHODS

Hemodialysis patients aged ≥ 65 years without diagnosed dementia were included. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE). CKD-MBD markers, serum magnesium, intact parathyroid hormone (PTH), 25-hydroxyvitamin D (25-OHD), fibroblast growth factor (FGF)-23, and soluble α-klotho were measured.

RESULTS

Overall, 390 patients with a median age of 74 (interquartile range, 70-80) years, mean serum magnesium level of 2.4 ± 0.3 mg/dL, and median MoCA and MMSE scores of 25 (22-26) and 28 (26-29), respectively, were analyzed. MoCA and MMSE scores were significantly higher (preserved cognitive function) in the high-magnesium group than in the low-magnesium group according to the unadjusted linear regression analysis (β coefficient [95% confidence interval (CI)] 1.05 [0.19, 1.92], P = 0.017 for MoCA; 1.2 [0.46, 1.94], P = 0.002 for MMSE) and adjusted multivariate analysis with risk factors for dementia (β coefficient [95% CI] 1.12 [0.22, 2.02], P = 0.015 for MoCA; 0.92 [0.19, 1.65], P = 0.014 for MMSE).

CONCLUSIONS

Higher serum magnesium levels might be associated with preserved cognitive function in hemodialysis patients. Conversely, significant associations were not observed between cognitive function and intact PTH, 25-OHD, FGF-23, or soluble α-klotho levels.

Indoxyl sulfate induces apoptotic cell death by inhibiting glycolysis in human astrocytes

BACKGROUND

Neurologic complications, such as cognitive and emotional dysfunction, have frequently been observed in chronic kidney disease (CKD) patients. Previous research shows that uremic toxins play a role in the pathogenesis of CKD-associated cognitive impairment. Since astrocytes contribute to the protection and survival of neurons, astrocyte function and brain metabolism may contribute to the pathogenesis of neurodegeneration. Indoxyl sulfate (IS) is the most popular uremic toxin. However, how IS-induced astrocyte injury brings about neurologic complications in CKD patients has not been elucidated.

METHODS

The rate of extracellular acidification was measured in astrocytes when IS (0.5-3 mM, 4 or 7 days) treatment was applied. The hexokinase 1 (HK1), pyruvate kinase isozyme M2 (PKM2), pyruvate dehydrogenase (PDH), and phosphofructokinase (PFKP) protein levels were also measured. The activation of the apoptotic pathway was investigated using a confocal microscope, fluorescence- activated cell sorting, and cell three-dimensional imaging was used.

RESULTS

In astrocytes, IS affected glycolysis in not only dose-dependently but also time-dependently. Additionally, HK1, PKM2, PDH, and PFKP levels were decreased in IS-treated group when compared to the control. The results were prominent in cases with higher doses and longer exposure duration. The apoptotic features after IS treatment were also observed.

CONCLUSION

Our results showed that the inhibition of glycolysis by IS in astrocytes leads to cell death via apoptosis. Specifically, longterm and higher-dose exposures had more serious effects on astrocytes. Our results suggest that the glycolysis pathway and related targets could provide a novel approach to cognitive dysfunction in CKD patients.

Structural equation modelling of the role of cognition in functional interference and treatment nonadherence among haemodialysis patients

BACKGROUND AND OBJECTIVES

Cognitive impairment is common in haemodialysis patients and associated with adverse health outcomes. This may be due to cognitive impairments interfering with daily functioning and self-care, but evidence is limited. This cross-sectional study aims to explore the interrelationships between cognition and functional outcomes in haemodialysis patients.

METHODS

Haemodialysis patients completed measures of objective cognitive function (Montreal Cognitive Assessment), everyday problem-solving skills (scenario-based task), and subjective cognitive complaints (self-report). Participants also self-reported sociodemographic information, functional interference, treatment nonadherence, and mood and fatigue symptoms. Patients' clinical data including comorbidities and lab results were extracted from medical record. Structural equation modelling was performed.

RESULTS

A total of 268 haemodialysis patients (mean age = 59.87 years; 42.5% female) participated. The final model showed satisfactory fit: CFI = 0.916, TLI = 0.905, RMSEA = 0.033 (90% confidence interval 0.024 to 0.041), SRMR = 0.066, χ2(493) = 618.573 (p < .001). There was a negative association between objective cognitive function and subjective cognitive complaints. Cognitive complaints were positively associated with both functional interference and treatment nonadherence, whereas objective performance was not. Everyday problem-solving skills emerged as a distinct aspect of cognition not associated with objective performance or subjective complaints, but had additive utility in predicting functional interference.

CONCLUSIONS

Subjective cognitive complaints and everyday problem-solving skills appear to be stronger predictors of functional variables compared to objective performance based on traditional tests. Routine screening of everyday cognitive difficulties may allow for early identification of dialysis patients at risk of cognitive impairment, functional interference, treatment nonadherence, and poor clinical outcomes.

Structural equation modeling analysis of factors influencing decisional conflict between dialysis modality among end-stage kidney disease patients in Wuhan

OBJECTIVES

To explore the influencing factors and relationships associated with decisional conflict of dialysis modality in End-stage kidney disease (ESKD) patients.

METHODS

This study was a survey-based cross-sectional investigation conducted on 150 ESKD patients in a third-class hospital in Wuhan. The general information questionnaire, decisional conflict scale, Montreal cognitive assessment, frail scale, perceived social support scale, and brief health literacy screen were used for investigation. SPSS 25.0 was used to compare the differences between the decisional and non-decisional conflict groups, and AMOS 23.0 was used to construct a structural equation model to explore the influencing factors.

RESULTS

The incidence of decisional conflict in 150 ESKD patients was 33.3% (50/150). Binary logistic regression analysis showed that the independent risk factors for decisional conflict of dialysis modality in ESKD patients included monthly household income (OR = 0.184), cognitive function (OR = 7.0), social support (OR = 0.891), health literacy (OR = 0.608), the level of eGFR (OR = 1.488), and the level of cTnI (OR = 9.558). The constructed path analysis model had a good fit (x2/df = 1.499, GFI = 0.957, AGFI = 0.911, NFI = 0.906, CFI = 0.967, RMSEA = 0.055). The path analysis showed that health literacy (0.577) had the greatest impact on the decisional conflict, with a direct effect of 0.480 and an indirect effect of 0.097 through cognitive function and monthly household income. Next was social support, with an effect value of 0.434.

CONCLUSIONS

In clinical practice, it is important to enhance the health literacy of patients and their families and to provide advanced education on dialysis plans. Additionally, in managing and planning chronic kidney disease progression and dialysis, it is recommended to regularly and systematically assess cognitive function, particularly before the patient's cognitive impairment worsens or the severity of the disease progresses. Advanced care planning can be established through collaboration between healthcare professionals and patients to ensure appropriate decision-making and management.

IMPLICATIONS FOR THE PROFESSION AND PATIENT CARE

This paper finds that the factors that influence and relate to dialysis methods in end-stage renal disease patients help nurses exercise autonomy better, assist patients in reducing their decisional conflict, and improve clinical outcomes.

PATIENT OR PUBLIC CONTRIBUTION

Patients received a relevant questionnaire survey, and caregivers assisted in conducting the study.

Altered brain texture features in end-stage renal disease patients: a voxel-based 3D brain texture analysis study

Introduction

Cognitive impairment in patients with end-stage renal disease (ESRD) is associated with brain structural damage. However, no prior studies have investigated the relationship between brain texture features and the cognitive function in ESRD patients. This study aimed to investigate changes in brain texture features in ESRD patients and their relationships with cognitive function using voxel-based 3D brain texture analysis (TA), and further predict individual cognitive-related brain damage in ESRD patients.

Methods

Forty-seven ESRD patients and 45 control subjects underwent whole-brain high-resolution 3D T1-weighted imaging scans and neuropsychological assessments. The voxel-based 3D brain TA was performed to examine inter-group differences in brain texture features. Additionally, within the ESRD group, the relationships of altered texture features with neuropsychological function and clinical indicators were analyzed. Finally, receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive ability of brain texture features for cognitive-related brain damage in ESRD patients.

Results

Compared to the control group, the ESRD group exhibited altered texture features in several brain regions, including the insula, temporal lobe, striatum, cerebellum, and fusiform gyrus (p < 0.05, Gaussian random-field correction). Some of these altered texture features were associated with scores from the Digit Symbol Substitution Test and the Trail Making Test Parts A (p < 0.05), and showed significant correlations with serum creatinine and calcium levels within the ESRD group (p < 0.05). Notably, ROC curve analysis revealed that the texture features in the right insula and left middle temporal gyrus could accurately predict cognitive-related brain damage in ESRD patients, with the area under the curve values exceeding 0.90.

Conclusion

Aberrant brain texture features may be involved in the neuropathological mechanism of cognitive decline, and have high accuracy in predicting cognitive-related brain damage in ESRD patients. TA offers a novel neuroimaging marker to explore the neuropathological mechanisms of cognitive impairment in ESRD patients, and may be a valuable tool to predict cognitive decline.

Association of chronic kidney disease with cognitive impairment risk in middle-aged and older adults: the first longitudinal evidence from CHARLS

Previous studies have yielded inconsistent results regarding the association between chronic kidney disease (CKD) and the risk of cognitive impairment (CI). This study aimed to investigate the longitudinal association of CKD with CI risk in the Chinese middle-aged and older population. A total of 16,515 CI-free participants 45 years of age or older including 15,595 without CKD and 920 with CKD were followed from 2011 until 2018 (median [interquartile range]: 7 [5.5-7]) to detect incident CI. Over the follow-up, 648 participants developed CI. Data were analyzed using multi-adjusted Cox proportional hazard regression and Laplace regression. The incidence rate (IR) of CI was significantly higher in individuals with CKD at 11.46 per 1,000 person-years (95% confidence interval [CI], 8.90 to 14.76) than in those without CKD at 6.38 per 1,000 person-years (95% CI, 5.89 to 6.92). Compared to those without CKD, the hazard ratios of those with CKD was 1.56 (95% CI, 1.19 to 2.04) for CI. Participants with CKD in the middle-aged group (45-54 years) exhibited a heightened risk of CI in age-stratified analyses. CKD accelerated the onset of CI by 1.24 years (10th percentile difference [PD]; 95% CI, -2.03 to -0.43, p < 0.01). The findings from this study revealed a significantly increased risk of CI in individuals with CKD, especially in middle-aged population, where the risk appeared to be more pronounced. This observation underscores the importance of early detection and intervention strategies to alleviate the potential cognitive decline associated with CKD.

Cerebral white matter injury in haemodialysis patients: a cross-sectional tract-based spatial statistics and fixel-based analysis

Background

End-stage renal disease (ESRD) patients on maintenance haemodialysis (HD) often have damage to brain white matter (WM) and cognitive impairment. However, whether this damage is caused by maintenance HD or renal dysfunction is unclear. Herein we investigate the natural progression of WM damage in patients with ESRD and the effects of HD on WM using tract-based spatial statistics (TBSS) and fixel-based analysis (FBA).

Methods

Eighty-one ESRD patients, including 41 with no dialysis (ND) and 40 on HD, and 46 healthy controls (HCs) were enrolled in this study. The differences in WM among the three groups [ESRD patients with HD (ESRD-HD), ESRD patients without HD (ESRD-ND) and HCs] were analysed using TBSS and FBA. Pairwise comparison was then used to compare the differences in WM between two groups. The relationships between WM and neurocognitive assessments/clinical data were analysed in ESRD patients with and without HD.

Results

The damage to WM in ESRD-ND and ESRD-HD appeared around the lateral ventricles in TBSS, while FBA reflected that the changes had extended to adjacent WM in the anterior hemisphere, with a larger region in ESRD-HD compared with ESRD-ND and the brainstem was also widely affected in ESRD-HD. The Montreal Cognitive Assessment (MoCA) scores were lower in the ESRD-HD group. RD in the body of the corpus callosum were negatively correlated with MoCA scores in both groups. Fiber density and cross-section (FDC) in the left thalamo-prefrontal projection (T_PREFL) and left and right cingulum (CGL and CGR) were positively correlated with MoCA scores in both groups. Creatinine (Cr) was positively correlated with FDC in some frontal projection fibres in the striatum and thalamus, CG and fronto-pontine tract and was positively correlated with FD mainly in premotor projection fibres in the striatum and thalamus in the ESRD-HD group. Cr was negatively correlated with mean and radial diffusivity in regions of the corona radiata in the ESRD-ND group.

Conclusions

FBA is more sensitive in detecting differences between ESRD patients and HCs. When ESRD patients receive maintenance HD, the degree of WM damage may not be aggravated, but the range of damaged WM may be expanded, especially in the anterior hemisphere and brainstem. Some of these changes in the anterior hemisphere may contribute to cognitive decline.

Kidney-brain axis in the pathogenesis of cognitive impairment

The kidney-brain axis is a bidirectional communication network connecting the kidneys and the brain, potentially affected by inflammation, uremic toxin, vascular injury, neuronal degeneration, and so on, leading to a range of diseases. Numerous studies emphasize the disruptions of the kidney-brain axis may contribute to the high morbidity of neurological disorders, such as cognitive impairment (CI) in the natural course of chronic kidney disease (CKD). Although the pathophysiology of the kidney-brain axis has not been fully elucidated, epidemiological data indicate that patients at all stages of CKD have a higher risk of developing CI compared with the general population. In contrast to other reviews, we mentioned some commonly used medicines in CKD that may play a pivotal role in the pathogenesis of CI. Revealing the pathophysiology interactions between kidney damage and brain function can reduce the potential risk of future CI. This review will deeply explore the characteristics, indicators, and potential pathophysiological mechanisms of CKD-related CI. It will provide a theoretical basis for identifying CI that progresses during CKD and ultimately prevents and treats CKD-related CI.

Increased Blood-Brain Barrier Permeability and Cognitive Impairment in Patients With ESKD

Introduction

Chronic kidney disease (CKD) is associated with an increased risk of cognitive impairment. This cognitive impairment is associated with an increased permeability of blood-brain barrier (BBB) in rodents with CKD, linked to activation of aryl hydrocarbon receptor (AhR) by indoxyl sulphate (IS). The objective of the BREIN study was to confirm the increased BBB permeability in humans with CKD.

Method

The BREIN comparative study (NCT04328415) prospectively included patients with end-stage kidney disease (ESKD) and controls healthy volunteers matched in age, sex, and level of education to a patient. In all participants, BBB permeability was quantified by brain 99mTc-DTPA SPECT/CT as a percentage of injected activity (% IA). A battery of neurocognitive tests was performed, and serum uremic toxins accumulation and AhR activation were assessed.

Results

Fifteen patients with ESKD and 14 healthy volunteers were analyzed. Patients with ESKD had higher BBB permeability compared to controls: 0.29 ± 0.07 versus 0.14 ± 0.06 %IA, P = 0.002. Patients with ESKD displayed lower Montreal Cognitive Assessment test (MoCA) score: 22.0 ± 5.0 versus 27.3 ± 2.8, P = 0.008; impaired short-term memory (doors test): 12.5 ± 3.4 versus 16.5 ± 3.4, P = 0.005; higher Beck depression score 8.1 ± 9.1 versus 2.7 ± 3.4, P = 0.046; and slightly more daily cognitive complaints: 42.5 ± 29.3 versus 29.8 ± 14.0 P = 0.060. Patients with ESKD displayed higher IS levels (86.1 ± 48.4 vs. 3.2 ± 1.7 μmol/l, P = 0.001) and AhR activating potential (37.7 ± 17.8% vs. 24.7 ± 10.4%, P = 0.027). BBB permeability was inversely correlated with MoCA score (r = -0.60, 95% confidence interval [-0.772 to -0.339], P = 0.001) in the overall population.

Conclusion

Patients with ESKD display an increased BBB permeability compared to matched healthy volunteers. Association with uremic toxins and cognitive impairment needs to be assessed in larger cohorts of patients.

Curcumin Supplementation and Vascular and Cognitive Function in Chronic Kidney Disease: A Randomized Controlled Trial

Chronic kidney disease (CKD) increases the risk of cardiovascular disease and cognitive impairment. Curcumin is a polyphenol that improves vascular and cognitive function in older adults; however, its effects on vascular and cognitive function in patients with CKD are unknown. We hypothesized that curcumin supplementation would improve vascular and cognitive function in patients with CKD. Eighty-eight adults diagnosed with stage 3b or 4 CKD (aged 66 ± 8 years, 75% male) participated in a 12-month, randomized, double-blind, placebo-controlled study to test the effects of curcumin (Longvida®, 2000 mg/day) on vascular and cognitive function. Our primary outcome was brachial artery flow-mediated dilation (FMD). Our secondary outcomes were nitroglycerin-mediated dilation, carotid-femoral pulse wave velocity (cfPWV), and cognitive function assessed via the NIH Toolbox Cognition Battery. At baseline, the mean estimated glomerular filtration rate was 34.7 ± 10.8, and the median albumin/creatinine ratio was 81.9 (9.7, 417.3). A total of 44% of participants had diabetes. Compared with placebo, 12 months of curcumin did not improve FMD (median change from baseline was -0.7 (-2.1, 1.1) and -0.1 (-1.5, 1.5) for curcumin and placebo, respectively, with p = 0.69). Similarly, there were no changes in nitroglycerin-mediated dilation, cfPWV, or cognitive outcomes. These results do not support chronic curcumin supplementation to improve vascular and cognitive function in patients with CKD.

The impact of chronic kidney disease on cognitive function

PURPOSE OF REVIEW

The risk of cognitive impairment is higher in people with CKD than in the general population. The complex relationship between CKD and cognitive dysfunction has not been extensively characterized. Here, we review epidemiological associations, specific patterns of CKD-related cognitive impairment, the underlying mechanisms, and recently published data on relevant biomarkers.

RECENT FINDINGS

Despite some discrepancies, recent published studies have confirmed that CKD is associated with cognitive function (e.g. incident cognitive events). Although patients with CKD often exhibit impairments in executive functions and attention, it is noteworthy that other cognitive functions (e.g. memory) can be preserved. The key mechanisms described recently include vascular damage, genetic factors, the accumulation of uremic toxins, disruption of the blood-brain barrier, glymphatic system dysfunction, and changes in the gut-brain axis. Kidney function is increasingly seen as a game changer in the interpretation of biomarkers of cognitive impairment and, especially, hallmarks of Alzheimer disease.

SUMMARY

The data reviewed here highlight the need for interdisciplinary collaboration between nephrologists and neurologists in the care of patients with CKD at risk of cognitive impairment. In order to further improving diagnosis and therapy, future research must elucidate the mechanisms underlying the CKD-cognitive impairment association and confirm the value of biomarkers.

Synergistic susceptibility to environmental lead toxicity in chronic kidney disease

PURPOSE OF REVIEW

While high levels of lead exposure, as occurs accidentally or occupationally, can cause toxicity across multiple organ systems, the hazard of commonly encountered levels of lead in the environment remains unresolved. Challenges to researching the health effects of lead include its complex interplay with renal function, rendering analyses at risk of unaccounted confounding, and the likely small effect size of environmental levels of exposure. While children are known to be disproportionately susceptible to lead toxicity, resulting in appropriately more stringent regulatory surveillance for those under 5 years old, emerging evidence suggests that those with chronic kidney disease (CKD) similarly are at a greater risk. This review summarizes the role of environmental lead toxicity as a potential cause and consequence of CKD.

RECENT FINDINGS

Whether environmental lead exposure causes CKD remains debatable, with little recent research advancing the conflicting, mostly cross-sectional, analyses from years ago. However, an emerging body of evidence suggests that CKD increases the susceptibility to lead toxicity. Higher circulating lead levels and lower urinary excretion result in greater lead accumulation in CKD, with simultaneous greater risk of clinically meaningful disease. Recent studies suggest that levels of lead found commonly in the United States drinking water supply, and currently permissible by the Environmental Protection Agency, associate with hematologic toxicity in those with advanced CKD. Whether environmental lead contamination may have additional negative health impact among this at-risk population, including cardiovascular and neurocognitive disease, warrants further study.

SUMMARY

The underlying pathophysiology of kidney disease synergizes the susceptibility to environmental lead toxicity for those with CKD. Low levels of exposure, as found commonly in the United States water supply, may have adverse health impact in CKD. Further research will be needed to determine if more stringent environmental regulations are warranted to protect the health of all.

Frailty in patients on dialysis

Frailty is a condition that is frequently observed among patients undergoing dialysis. Frailty is characterized by a decline in both physiological state and cognitive state, leading to a combination of symptoms, such as weight loss, exhaustion, low physical activity level, weakness, and slow walking speed. Frail patients not only experience a poor quality of life, but also are at higher risk of hospitalization, infection, cardiovascular events, dialysis-associated complications, and death. Frailty occurs as a result of a combination and interaction of various medical issues in patients who are on dialysis. Unfortunately, frailty has no cure. To address frailty, a multifaceted approach is necessary, involving coordinated efforts from nephrologists, geriatricians, nurses, allied health practitioners, and family members. Strategies such as optimizing nutrition and chronic kidney disease-related complications, reducing polypharmacy by deprescription, personalizing dialysis prescription, and considering home-based or assisted dialysis may help slow the decline of physical function over time in subjects with frailty. This review discusses the underlying causes of frailty in patients on dialysis and examines the methods and difficulties involved in managing frailty among this group.

Prevention of Chronic Kidney Disease and Its Complications in Older Adults

In an era marked by a global demographic shift towards an aging society, there is a heightened prevalence of chronic kidney disease (CKD) among older adults. The burden of CKD spans from kidney-related complications to impacting psychological well-being, giving rise to depressive symptoms and caregiver burnout. This article delves into CKD prevention strategies within the context of aging, contributing to the discourse by exploring its multifaceted aspects. The prevention of CKD in the older adults necessitates a comprehensive approach. Primary prevention is centered on the modification of risk factors, acknowledging the intricate interplay of various comorbidities. Secondary prevention focuses on early CKD identification. Tertiary prevention aims to address factors contributing to CKD progression and complications, emphasizing the importance of timely interventions. This comprehensive strategy aims to enhance the quality of life for individuals affected by CKD, decelerating the deterioration of functional status. By addressing CKD at multiple levels, this approach seeks to effectively and compassionately care for the aging population.

Cognitive Dysfunction Screening in Peritoneal Dialysis Patients: A Cross-Sectional Study

Background

Mild cognitive impairment (MCI) in peritoneal dialysis (PD) patients has been described as a risk factor for worse outcomes such as peritonitis, technique failure, and mortality. In this study, we aimed to determine the prevalence of MCI in a population of PD patients and identify the possible risk factors associated with MCI.

Materials and Methods

We performed an observational, cross-sectional study to evaluate cognitive function using the Montreal Cognitive Assessment (MOCA) test and the Mini Mental State Examination (MMSE) test in PD patients. Patients with diagnosis of dementia or severe neurologic impairment, active cancer, or infection were excluded.

Results

We evaluated 66 patients (mean age 60 years); 53% were male. Prevalence of MCI assessed by MOCA test and MMSE test was 65% and 33%, respectively. Predictors of MCI with MOCA test were higher age (P = 0.0001), lower education level (P = 0.005), need of a helper (P = 0.009), and continuous ambulatory PD modality (P = 0.019). Higher Charlson comorbidity index (P = 0.002), coronary artery disease (P = 0.006), and peripheral artery disease (P = 0.033) were also associated with MCI. Lower Kt/V (P = 0.012) and lower levels of normalized protein catabolic rate (nPCR; P < 0.000) were related to MCI. MCI patients had more episodes of peritonitis (P = 0.047). Multivariable analysis showed that lower education, Kt/V, and nPCR were the most relevant factors connected to MCI (P = 0.029, P = 0.037, and P = 0.019, respectively).

Conclusion

In our PD population, MCI was detected in more than half of the patients. Patients with MCI were older, had lower education level, more disease burden, and higher risk for developing peritonitis. Lower Kt/V and nPCR levels were associated with MCI.

Exploring the Cognitive Profiles of Haemodialysis Patients using Objective and Subjective Indicators: A Cross-sectional Observational Study

BACKGROUND

Cognitive impairment is common in haemodialysis patients and associated with adverse health outcomes. Previous work focused primarily on neuropsychological tests, the gold standard measure of cognition. However, these tests reflect performance under optimal conditions rather than performance in everyday life. This study aims to assess both objective and subjective cognition in haemodialysis patients.

METHODS

Adult haemodialysis patients completed measures of objective cognitive impairment (Montreal Cognitive Assessment), subjective cognitive complaints, mood and fatigue symptoms, and provided sociodemographic information. Clinical data such as comorbidity were extracted from patients' medical record.

RESULTS

A total of 268 haemodialysis patients (mean age = 59.87 years; 42.5% female) participated. Only 25.0% of the sample had normal cognition, while the rest had either objective cognitive impairments or clinically significant cognitive complaints, or both (both objective impairments and subjective complaints: 26.1%; objective impairments without complaint: 38.4%; significant complaints without objective impairments: 10.4%). Lower education was associated with the presence of objective cognitive impairments, whereas depression was associated with the presence of clinically significant cognitive complaints. Patients who exhibited both objective cognitive impairments and significant cognitive complaints were more likely to have diabetes and higher dialysis dose (Kt/V). Patients with objective cognitive impairments but no significant complaints were significantly older.

CONCLUSIONS

The cognitive burden of haemodialysis patients can be manifested as objective impairments and/or subjective complaints. When combined the two indicators may better represent the overall cognitive well-being in this population. There is a need to screen for cognitive difficulties and develop cognitive rehabilitative strategies in dialysis settings.

Animal models to study cognitive impairment of chronic kidney disease

Mild cognitive impairment (MCI) is common in people with chronic kidney disease (CKD), and its prevalence increases with progressive loss of kidney function. MCI is characterized by a decline in cognitive performance greater than expected for an individual age and education level but with minimal impairment of instrumental activities of daily living. Deterioration can affect one or several cognitive domains (attention, memory, executive functions, language, and perceptual motor or social cognition). Given the increasing prevalence of kidney disease, more and more people with CKD will also develop MCI causing an enormous disease burden for these individuals, their relatives, and society. However, the underlying pathomechanisms are poorly understood, and current therapies mostly aim at supporting patients in their daily lives. This illustrates the urgent need to elucidate the pathogenesis and potential therapeutic targets and test novel therapies in appropriate preclinical models. Here, we will outline the necessary criteria for experimental modeling of cognitive disorders in CKD. We discuss the use of mice, rats, and zebrafish as model systems and present valuable techniques through which kidney function and cognitive impairment can be assessed in this setting. Our objective is to enable researchers to overcome hurdles and accelerate preclinical research aimed at improving the therapy of people with CKD and MCI.

Assessing Cognition in CKD Using the National Institutes of Health Toolbox

Key Points

Participants with CKD had detectable cognitive deficits in fluid cognition, dexterity, and total cognition. Sex differences in cognition exist in people with CKD.

Background

CKD is largely an age-related clinical disorder with accelerated cognitive and cardiovascular aging. Cognitive impairment is a well-documented occurrence in midlife and older adults with CKD and affects multiple domains. We examined cognition function and potential sex differences in cognition in adults with CKD.

Methods

We included 105 individuals (49.5% women) with CKD stage 3b–4 (eGFR, 15–44 ml/min) from the Bicarbonate Administration in CKD Trial (NCT02915601 ). We measured cognitive function using the National Institutes of Health Toolbox Cognition Battery, which assesses cognitive and motor measures, such as executive function, attention, memory, and dexterity. All study measures were collected and analyzed at the study baseline.

Results

The mean (SD) age and eGFR were 61±12 years and 34.9±9.8 ml/min per 1.73 m2. Overall, when compared with the National Institutes of Health Toolbox reference population, participants scored, on average, below the 50th percentile across all cognitive domain tests and the dexterity test. Total cognition scores were also below the 50th percentile. Participants with stage 4 CKD had significantly lower fluid cognition scores compared with those with CKD stage 3b (β -estimate −5.4 [95% confidence interval, −9.8 to −0.9]; P = 0.03). Female participants with CKD performed significantly better on the episodic memory tests and dexterity tests (dominant and nondominant pegboard tests) and had higher crystallized cognition scores, on average, compared with male participants.

Conclusions

Participants with CKD had detectable cognitive deficits in fluid cognition, dexterity, and total cognition. In addition, sex differences in cognitive measures were found among people with CKD.

Association between serum 25-hydroxyvitamin D3 level and cognitive impairment in older chronic kidney disease patients

This study aims to examine whether hypovitaminosis D was associated with cognitive impairment among chronic kidney patients with different level of albuminuria. This population-based cross-sectional study was conducted on elderly (over 60 years old) with urine albumin to creatinine ratio (UACR) ≥ 30 mg/g from 2011 to 2014 in the US National Health and Nutrition Examination Survey (NHANES). Cognitive function was assessed by the Consortium to Establish a Registry for Alzheimer's Disease Word List Learning (CERAD). Subjects were divided into 2 groups according to the absence or presence of cognitive impairment and a propensity score matching (PSM) was further conducted. The association was assessed with Spearman correlation and logistic regression analysis. The positive association of 25-hydroxyvitamin D3 (25(OH)D3) and cognitive score was presented. PSM analysis revealed that a higher level of 25(OH)D3 correlated to a better cognitive function in CKD patients with albuminuria, especially in patients with 30 mg/g ≤ UACR < 300 mg/g. This study indicated that a low 25(OH)D3 level was associated with poor cognitive performance, especially in patients with microalbuminuria. Thus, early diagnosis of vitamin D insufficiency and an effective intervention might be a useful therapeutic strategy to prevent cognitive decline in patients with the progression of renal dysfunction.

Effects of a Personalized Diet on Nutritional Status and Renal Function Outcome in Nephrectomized Patients with Renal Cancer

Nutritional therapy (NT) based on a controlled protein intake represents a cornerstone in managing chronic kidney disease (CKD). However, if a CKD patient is at the same time affected by cancer, oncologists and nutritionists tend to suggest a dietary regimen based on high protein intake to avoid catabolism and malnutrition. International guidelines are not clear when we consider onco-nephrological patients and, as a consequence, no clinical shared strategy is currently applied in clinical practice. In particular, no precise nutritional management is established in nephrectomized patients for renal cell carcinoma (RCC), a specific oncological cohort of patients whose sudden kidney removal forces the remnant one to start a compensatory mechanism of adaptive hyperfiltration. Our study aimed to investigate the efficacy of a low-normal-protein high-calorie (LNPHC) diet based on a Mediterranean model in a consecutive cohort of nephrectomized RCC patients using an integrated nephrologist and nutritionist approach. A consecutive cohort of 40 nephrectomized RCC adult (age > 18) patients who were screened for malnutrition (malnutrition screening tool, MST < 2) were enrolled in a tertiary institution between 2020 and 2022 after signing a specific informed consent form. Each patient underwent an initial nephrological and nutritional evaluation and was subsequently subjected to a conventional CKD LNPHC diet integrated with aproteic foods (0.8 g/Kg/die: calories: 30-35 kcal per kg body weight/die) for a period of 6 months (±2 months). The diet was structured after considering eGFR (CKD-EPI 2021 creatinine formula), comorbidities, and nutritional status. MST, body mass index (BMI), phase angle (PA), fat mass percentage (FM%), fat-free mass index (FFMI), body cell mass index (BCMI), extracellular/intracellular water ratio (ECW/ICW), extracellular matrix/body cell mass ratio (ECM/BCM), waist/hip circumference ratio (WHC), lab test exams, and clinical variables were examined at baseline and after the study period. Our results clearly highlighted that the LNPHC diet was able to significantly improve several nutritional parameters, avoiding malnutrition and catabolism. In particular, the LNPHC diet preserved the BCM index (delta on median, ΔM + 0.3 kg/m2) and reduced the ECM/BCM ratio (ΔM - 0.03 *), with a significant reduction in the ECW/ICW ratio (ΔM - 0.02 *), all while increasing TBW (ΔM + 2.3% *). The LNPHC diet was able to preserve FFM while simultaneously depleting FM and, moreover, it led to a significant reduction in urea (ΔM - 11 mg/dL **). In conclusion, the LNPHC diet represents a new important therapeutic strategy that should be considered when treating onco-nephrological patients with solitary kidney due to renal cancer.

Association of cognitive impairment with the interaction between chronic kidney disease and depression: findings from NHANES 2011-2014

BACKGROUND

Cognitive impairment (CoI), chronic kidney disease (CKD), and depression are prevalent among older adults and are interrelated, imposing a significant disease burden. This study evaluates the association of CKD and depression with CoI and explores their potential interactions.

METHOD

Data for this study were sourced from the 2011-2014 National Health and Nutritional Examination Survey (NHANES). Multiple binary logistic regression models assessed the relationship between CKD, depression, and CoI while controlling for confounders. The interactions were measured using the relative excess risk of interaction (RERI), the attributable proportion of interaction (AP), and the synergy index (S).

RESULTS

A total of 2,666 participants (weighted n = 49,251,515) were included in the study, of which 700 (16.00%) had CoI. After adjusting for confounding factors, the risk of CoI was higher in patients with CKD compared to non-CKD participants (odds ratio [OR] = 1.49, 95% confidence interval [CI]:1.12-1.99). The risk of CoI was significantly increased in patients with depression compared to those without (OR = 2.29, 95% CI: 1.73-3.03). Furthermore, there was a significant additive interaction between CKD and depression in terms of the increased risk of CoI (adjusted RERI = 2.01, [95% CI: 0.31-3.71], adjusted AP = 0.50 [95% CI: 0.25-0.75], adjusted S = 2.97 [95% CI: 1.27-6.92]).

CONCLUSION

CKD and depression synergistically affect CoI, particularly when moderate-to-severe depression co-occurs with CKD. Clinicians should be mindful of the combined impact on patients with CoI. Further research is needed to elucidate the underlying mechanisms and assess the effects specific to different CKD stages.

The covariant structural and functional neuro-correlates of cognitive impairments in patients with end-stage renal diseases

Introduction

Cognitive impairment (CI) is a common complication of end-stage renal disease (ESRD) that is associated with structural and functional changes in the brain. However, whether a joint structural and functional alteration pattern exists that is related to CI in ESRD is unclear.

Methods

In this study, instead of looking at brain structure and function separately, we aim to investigate the covariant characteristics of both functional and structural aspects. Specifically, we took the fusion analysis approach, namely, multimodal canonical correlation analysis and joint independent component analysis (mCCA+jICA), to jointly study the discriminative features in gray matter volume (GMV) measured by T1-weighted (T1w) MRI, fractional anisotropy (FA) in white matter measured by diffusion MRI, and the amplitude of low-frequency fluctuation (ALFF) measured by blood oxygenation-level-dependent (BOLD) MRI in 78 ESRD patients versus 64 healthy controls (HCs), followed by a mediation effect analysis to explore the relationship between neuroimaging findings, cognitive impairments and uremic toxins.

Results

Two joint group-discriminative independent components (ICs) were found to show covariant abnormalities across FA, GMV, and ALFF (all p < 0.05). The most dominant joint IC revealed associative patterns of alterations of GMV (in the precentral gyrus, occipital lobe, temporal lobe, parahippocampal gyrus, and hippocampus), alterations of ALFF (in the precuneus, superior parietal gyrus, and superior occipital gyrus), and of white matter FA (in the corticospinal tract and inferior frontal occipital fasciculus). Another significant IC revealed associative alterations of GMV (in the dorsolateral prefrontal and orbitofrontal cortex) and FA (in the forceps minor). Moreover, the brain changes identified by FA and GMV in the above-mentioned brain regions were found to mediate the negative correlation between serum phosphate and mini-mental state examination (MMSE) scores (all p < 0.05).

Conclusion

The mCCA+jICA method was demonstrated to be capable of revealing covariant abnormalities across neuronal features of different types in ESRD patients as contrasted to HCs, and joint brain changes may play an important role in mediating the relationship between serum toxins and CIs in ESRD. Our results show the mCCA+jICA fusion analysis approach may provide new insights into similar neurobiological studies.

Cognitive Impairment Related to Chronic Kidney Disease Is Associated with a Decreased Abundance of Membrane-Bound Klotho in the Cerebral Cortex

Cognitive impairment (CI) is a complication of chronic kidney disease (CKD) that is frequently observed among patients. The aim of this study was to evaluate the potential crosstalk between changes in cognitive function and the levels of Klotho in the brain cortex in an experimental model of CKD. To induce renal damage, Wistar rats received a diet containing 0.25% adenine for six weeks, while the control group was fed a standard diet. The animals underwent different tests for the assessment of cognitive function. At sacrifice, changes in the parameters of mineral metabolism and the expression of Klotho in the kidney and frontal cortex were evaluated. The animals with CKD exhibited impaired behavior in the cognitive tests in comparison with the rats with normal renal function. At sacrifice, CKD-associated mineral disorder was confirmed by the presence of the expected disturbances in the plasma phosphorus, PTH, and both intact and c-terminal FGF23, along with a reduced abundance of renal Klotho. Interestingly, a marked and significant decrease in Klotho was observed in the cerebral cortex of the animals with renal dysfunction. In sum, the loss in cerebral Klotho observed in experimental CKD may contribute to the cognitive dysfunction frequently observed among patients. Although further studies are required, Klotho might have a relevant role in the development of CKD-associated CI and represent a potential target in the management of this complication.

White matter hyperintensity patterns: associations with comorbidities, amyloid, and cognition

BACKGROUND

White matter hyperintensities (WMHs) are often measured globally, but spatial patterns of WMHs could underlie different risk factors and neuropathological and clinical correlates. We investigated the spatial heterogeneity of WMHs and their association with comorbidities, Alzheimer's disease (AD) risk factors, and cognition.

METHODS

In this cross-sectional study, we studied 171 cognitively unimpaired (CU; median age: 65 years, range: 50 to 89) and 51 mildly cognitively impaired (MCI; median age: 72, range: 53 to 89) individuals with available amyloid (18F-flutementamol) PET and FLAIR-weighted images. Comorbidities were assessed using the Cumulative Illness Rating Scale (CIRS). Each participant's white matter was segmented into 38 parcels, and WMH volume was calculated in each parcel. Correlated principal component analysis was applied to the parceled WMH data to determine patterns of WMH covariation. Adjusted and unadjusted linear regression models were used to investigate associations of component scores with comorbidities and AD-related factors. Using multiple linear regression, we tested whether WMH component scores predicted cognitive performance.

RESULTS

Principal component analysis identified four WMH components that broadly describe FLAIR signal hyperintensities in posterior, periventricular, and deep white matter regions, as well as basal ganglia and thalamic structures. In CU individuals, hypertension was associated with all patterns except the periventricular component. MCI individuals showed more diverse associations. The posterior and deep components were associated with renal disorders, the periventricular component was associated with increased amyloid, and the subcortical gray matter structures was associated with sleep disorders, endocrine/metabolic disorders, and increased amyloid. In the combined sample (CU + MCI), the main effects of WMH components were not associated with cognition but predicted poorer episodic memory performance in the presence of increased amyloid. No interaction between hypertension and the number of comorbidities on component scores was observed.

CONCLUSION

Our study underscores the significance of understanding the regional distribution patterns of WMHs and the valuable insights that risk factors can offer regarding their underlying causes. Moreover, patterns of hyperintensities in periventricular regions and deep gray matter structures may have more pronounced cognitive implications, especially when amyloid pathology is also present.

Association between cognitive function and skeletal muscle in patients undergoing maintenance hemodialysis

Background

Patients on hemodialysis have a higher burden of cognitive impairment than individuals of the same age in the general population. Studies have found a link between cognition and skeletal muscle function. However, few studies have investigated these associations and the underlying mechanisms in patients on hemodialysis.

Methods

A total of 166 patients on hemodialysis were enrolled in this longitudinal study. Cognitive function was assessed by Montreal Cognitive Assessment (MoCA) scores. Skeletal muscle indicators were evaluated using Inbody S10. Plasma brain-derived neurotrophic factor (BDNF) concentrations were measured by enzyme-linked immunosorbent assay. The primary outcome was a change in the MoCA scores. A mediation analysis was performed to examine the indirect effect of skeletal muscle on cognitive decline through BDNF.

Results

Among the 166 patients, the average age was 49.9 ± 11.2 years. Of these patients with a median follow-up of 1,136 days, 133 participated in the study. We defined MoCA scores decreased by ≥2 points at 3 years from the baseline measurement as cognitive decline (CD). Compared to the cognitively unchanged group, patients with CD had significantly lower fat-free mass, soft lean mass, skeletal muscle mass, and skeletal muscle index (all P<0.05). After adjusting for potential confounders, skeletal muscle indicators were protective predictors of CD. A significant increase in plasma BDNF levels was observed in the CD group. Mediation analysis suggested that BDNF played a mediating role of 20-35% between cognitive impairment and skeletal muscle.

Conclusion

Skeletal muscle is a protective predictor of CD in patients undergoing dialysis. BDNF mediates the relationship between cognitive impairment and skeletal muscle function.

Cognitive Impairment and Brain Atrophy in Patients with Chronic Kidney Disease

In Japan, the aging of the population is rapidly accelerating, with an increase in patients with chronic kidney disease (CKD) and those undergoing dialysis. As a result, the number of individuals with cognitive impairment (CI) is rising, and addressing this issue has become an urgent problem. A notable feature of dementia in CKD patients is the high frequency of vascular dementia, making its prevention through the management of classical risk factors such as hypertension, diabetes mellitus, dyslipidemia, smoking, etc., associated with atherosclerosis and arteriosclerosis. Other effective measures, including the use of renin-angiotensin system inhibitors, addressing anemia, exercise therapy, and lifestyle improvements, have been reported. The incidence and progression of CI may also be influenced by the type of kidney replacement therapy, with reports suggesting that long-duration dialysis, low-temperature hemodialysis, peritoneal dialysis, and kidney transplantation can have a preferable effect on the preservation of cognitive function. In conclusion, patients with CKD are at a higher risk of developing CI, with brain atrophy being a contributing factor. Despite the identification of various preventive measures, the evidence substantiating their efficacy remains limited across all studies. Future expectations lie in large-scale randomized controlled trials.

Polyvascular atherosclerosis and renal dysfunction increase the odds of cognitive impairment in vascular disease: findings of the LipidCardio study

INTRODUCTION

Growing evidence suggests a causal role for atherosclerotic vascular disease in cognitive impairment and dementia. Atherosclerosis may present as monovascular disease (monoVD) or as widespread polyvascular atherosclerotic disease (polyVD). Evidence on the relationship between monoVD or polyVD and cognitive impairment is limited.

METHODS

We conducted a cross-sectional analysis of baseline data from the LipidCardio Study. The main outcome measure was the presence of cognitive impairment, defined as a Mini-Mental State Examination (MMSE) score < 26.

RESULTS

The mean age was 71.5 years, 30.3% were female, 17.3% had no evidence of large-vessel atherosclerosis, 71.1% had monoVD, and 11.7% had polyVD, defined as the presence of atherosclerosis in ≥ 2 vascular territories (coronary, cerebral, aortic, or lower extremity). A total of 21.6% had cognitive impairment according to the prespecified cutoff (MMSE < 26). Overall, the odds of cognitive impairment increased for each additional vascular territory affected by atherosclerosis [adjusted odds ratio 1.76, 95% confidence interval (CI) 1.21-2.57, p = 0.003]. Furthermore, there was evidence for an interaction between vascular disease and chronic kidney disease (CKD). The odds of cognitive impairment were not greater in the monoVD subgroup compared to those without any atherosclerosis, if CKD was absent (OR 0.98, 95% CI 0.48-2.10; p = 0.095), while the odds ratio (OR) of cognitive impairment with polyVD compared to no atherosclerosis was 2.71 (95% CI 1.10-6.92; p = 0.031). In contrast, in patients with CKD, both monoVD and polyVD were associated with significantly higher odds of cognitive impairment than no atherosclerosis.

CONCLUSIONS

PolyVD is associated with increased odds of cognitive impairment. MonoVD is associated with cognitive impairment only in the presence of CKD.

Increased serum methylmalonic acid levels were associated with the presence of cognitive dysfunction in older chronic kidney disease patients with albuminuria

BACKGROUND

This study aimed to evaluate the correlation between serum methylmalonic acid (MMA) levels and cognition function in patients with chronic kidney disease (CKD).

METHODS

In this cross-sectional study, we included 537 CKD individuals aged ≥ 60-year-old with albuminuria from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. Four cognitive tests including the Digit Symbol Substitution Test (DSST), the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Delayed Recall and Word Learning tests, and the Animal Fluency test (AF) were performed. Associations between MMA and cognition scores were assessed with linear regression models.

RESULTS

MMA level was negatively associated with residual renal function and nutrition status. After multivariate adjustment, elevated serum MMA levels were independently correlated with decline of cognition in CKD patients with albuminuria.

CONCLUSION

Our study showed that higher serum MMA levels were independently associated with the presence of cognition dysfunction in CKD patients. The exact pathogenesis of MMA and cognition needs further research.

Connecting the Dots: The Cerebral Lymphatic System as a Bridge Between the Central Nervous System and Peripheral System in Health and Disease

As a recently discovered waste removal system in the brain, cerebral lymphatic system is thought to play an important role in regulating the homeostasis of the central nervous system. Currently, more and more attention is being focused on the cerebral lymphatic system. Further understanding of the structural and functional characteristics of cerebral lymphatic system is essential to better understand the pathogenesis of diseases and to explore therapeutic approaches. In this review, we summarize the structural components and functional characteristics of cerebral lymphatic system. More importantly, it is closely associated with peripheral system diseases in the gastrointestinal tract, liver, and kidney. However, there is still a gap in the study of the cerebral lymphatic system. However, we believe that it is a critical mediator of the interactions between the central nervous system and the peripheral system.

Impacts of Chronic Kidney Disease on Retinal Neurodegeneration: A Cross-Cohort Analysis

PURPOSE

To assess the cross-sectional and longitudinal associations between chronic kidney disease (CKD) and ganglion cell-inner plexiform layer (GCIPL) thickness in a UK Biobank population and a Chinese cohort.

DESIGN

Prospective observational cohort study and cross-sectional study.

METHOD

This study included 23,014 individuals without neurodegenerative diseases from the UK Biobank, and 3 years of annual follow-up data of 2197 individuals from a Chinese cohort. Three groups were defined by estimated glomerular filtration rate (eGFR) based on serum creatinine classifying CKD severity as no CKD, mild CKD, and moderate to severe CKD (MS-CKD). GCIPL thickness, measured using optical coherence tomography, was analyzed through linear regression over time to determine its decline rate in micrometers per year. Linear regression models were used to assess the correlation between renal function and both the baseline GCIPL thickness and the GCIPL decline rate.

RESULTS

The cross-sectional analysis in a largely white population showed that poorer renal function negatively correlated with GCIPL thickness with a mean of 0.15 µm thinner (95% confidence interval [CI] -0.30 to -0.01; P = .042) in mild CKD and 0.83 µm thinner (95% CI -1.34 to -0.32; P = .001) in MS-CKD compared with that of control subjects without CKD. Longitudinal analysis in the Chinese cohort showed that the GCIPL decreased more rapidly in persons with poorer renal function. After correcting for all confounding factors, the rate of GCIPL thinning was 0.30 µm/year (95% CI -0.41 to -0.19; P < .001) more in the mild CKD group and 0.52 µm/year (95% CI -0.79 to -0.26; P < .001) more in the MS-CKD group compared with control subjects without CKD. This relationship also occurred in individuals with diabetes or hypertension.

CONCLUSIONS

Poor renal function was associated with a lower baseline GCIPL thickness in the UK population and a faster decline rate in Chinese participants. However, the detailed underlying mechanisms still need further exploration.

Association of Plasma Claudin-5 with Age and Alzheimer Disease

The blood-brain barrier (BBB) plays pivotal roles in synaptic and neuronal functioning by sealing the space between adjacent microvascular endothelial cells. BBB breakdown is present in patients with mild cognitive impairment (MCI) or Alzheimer disease (AD). Claudin-5 (CLDN-5) is a tetra-spanning protein essential for sealing the intercellular space between adjacent endothelial cells in the BBB. In this study, we developed a blood-based assay for CLDN-5 and investigated its diagnostic utility using 100 cognitively normal (control) subjects, 100 patients with MCI, and 100 patients with AD. Plasma CLDN-5 levels were increased in patients with AD (3.08 ng/mL) compared with controls (2.77 ng/mL). Plasma levels of phosphorylated tau (pTau181), a biomarker of pathological tau, were elevated in patients with MCI or AD (2.86 and 4.20 pg/mL, respectively) compared with control subjects (1.81 pg/mL). In patients with MCI or AD, plasma levels of CLDN-5-but not pTau181-decreased with age, suggesting some age-dependent BBB changes in MCI and AD. These findings suggest that plasma CLDN-5 may a potential biochemical marker for the diagnosis of AD.

Protective effect of unsaturated fatty acids on cognitive impairment in CKD patients: Results from the National Health and Nutrition Examination Survey (2011-2014)

BACKGROUND

It is still unknown whether unsaturated fatty acids (UFA) have the same effect on preventing cognitive impairment in chronic kidney disease (CKD) patients as in healthy people.

OBJECTIVE

To investigate the protective effect of dietary UFA intake and proportion on cognitive impairment in patients with CKD.

METHODS

We extracted data from the National Health and Nutrition Examination Survey (NHANES, 2011-2014) on participants with a previous diagnosis of CKD and at least one complete cognitive assessment (Consortium to Establish a Registry for Alzheimer's Disease test, Animal Fluency Test and Digit Symbol Substitution Test). We used the lower quartile of the total scores of these three tests as the cut-off point, and divided the participants into two groups of normal cognitive performance and low cognitive performance to extract participants' intake of various UFA from the NHANES dietary module. The data were weighted using weighting parameters included in NHANES, and logistics regression and restricted cubic spline were used to analyze the protective effect of UFA intake on cognitive impairment in CKD participants.

RESULTS

We found that participants with low cognitive performance all had significantly lower intakes of total monounsaturated fatty acids, total polyunsaturated fatty acids, ω-3 UFA, ω-6 UFA and ω-9 UFA than participants with normal cognitive performance (p< 0.05), and the ω-6 UFA and ω-9 UFA had the most significant protective effects on cognitive impairment of participants. We also discovered that oleic and linoleic acids play important roles in protecting against cognitive impairment in CKD participants. The protective effect of oleic acid, but not linoleic acid, on cognitive impairment showed a nonlinear relationship. The changes in the proportion of monounsaturated fatty acids to polyunsaturated fatty acids, ω-6 UFA to ω-3 UFA, and oleic acid to linoleic acid did not affect the risk of cognitive impairment in CKD participants.

CONCLUSIONS

UFA can reduce the risk of cognitive impairment in CKD patients, especially oleic acid and linoleic acid have a more obvious protective effect on cognitive impairment in patients with CKD. Among them, the protective effect of linoleic acid on cognitive impairment was continuously enhanced with the increase of intake, indicating that linoleic acid may be the most important UFA to reduce cognitive impairment in CKD patients.

Medium cut-off dialyzer for middle molecular uremic toxins in AKI and chronic dialysis

Uremic toxins accumulate in patients affected by renal failure and can deposit in different organs, including the kidneys and heart. Given their physicochemical characteristics, uremic toxins can contribute to organ dysfunction due to several pathobiological actions at cellular and molecular levels. Several uremic compounds have been described in serum and plasma from patients with acute kidney injury (AKI) and kidney failure; they are usually classified based on their molecular size and protein-binding properties. In this scenario, new dialytic approaches have been proposed in the last few years with the aim of improving uremic toxin removal. Recent studies which focused on the use of medium cut-off membranes in patients on chronic hemodialysis have shown a discrete ability to remove β2-microglobulin and other middle molecules, such as kappa and lambda free light chains, complement factor D and α1-microglobulin. However, current evidence is mainly based on the impact on short-term outcomes and, consequently, longer observational studies are necessary to confirm the efficacy and safety of the medium cut-off dialyzer. Here we present the state-of-the-art on the clinical application of medium cut-off membranes in AKI and chronic dialysis patients.

Comparing Symmetric Dimethylarginine and Amyloid-β42 as Predictors of Alzheimer's Disease Development

Background

Physicians may soon be able to diagnose Alzheimer's disease (AD) in its early stages using fluid biomarkers like amyloid. However, it is acknowledged that additional biomarkers need to be characterized which would facilitate earlier monitoring of AD pathogenesis.

Objective

To determine if a potential novel inflammation biomarker for AD, symmetric dimethylarginine, has utility as a baseline serum biomarker for discriminating prodromal AD from cognitively unimpaired controls in comparison to cerebrospinal fluid amyloid-β42 (Aβ42).

Methods

Data including demographics, magnetic resonance imaging and fluorodeoxyglucose-positron emission tomography scans, Mini-Mental State Examination and Functional Activities Questionnaire scores, and biomarker concentrations were obtained from the Alzheimer's Disease Neuroimaging Initiative for a total of 146 prodromal AD participants and 108 cognitively unimpaired controls.

Results

Aβ42 (p = 0.65) and symmetric dimethylarginine (p = 0.45) were unable to predict age-matched cognitively unimpaired controls and prodromal AD participants. Aβ42 was negatively associated with regional brain atrophy and hypometabolism as well as cognitive and functional decline in cognitively unimpaired control participants (p < 0.05) that generally decreased in time. There were no significant associations between Aβ42 and symmetric dimethylarginine with imaging or neurocognitive biomarkers in prodromal AD patients.

Conclusions

Correlations were smaller between Aβ42 and neuropathological biomarkers over time and were absent in prodromal AD participants, suggesting a plateau effect dependent on age and disease stage. Evidence supporting symmetric dimethylarginine as a novel biomarker for AD as a single measurement was not found.

Subjective cognitive complaints in end-stage renal disease: a systematic review and meta-analysis

Cognitive impairment is common in patients with end-stage renal disease (ESRD) and is associated with compromised quality of life and functional capacity, as well as worse clinical outcomes. Most previous research and reviews in this area were focused on objective cognitive impairment, whereas patients' subjective cognitive complaints (SCCs) have been less well-understood. This systematic review aimed to provide a broad overview of what is known about SCCs in adult ESRD patients. Electronic databases were searched from inception to January 2022, which identified 221 relevant studies. SCCs appear to be highly prevalent in dialysis patients and less so in those who received kidney transplantation. A random-effects meta-analysis also shows that haemodialysis patients reported significantly more SCCs than peritoneal dialysis patients (standardised mean difference -0.20, 95% confidence interval -0.38 to -0.03). Synthesis of longitudinal studies suggests that SCCs remain stable on maintenance dialysis treatment but may reduce upon receipt of kidney transplant. Furthermore, SCCs in ESRD patients have been consistently associated with hospitalisation, depression, anxiety, fatigue, and poorer quality of life. There is limited data supporting a strong relation between objective and subjective cognition but preliminary evidence suggests that this association may be domain-specific. Methodological limitations and future research directions are discussed.