Effect of Kidney Dysfunction on Cerebral Cortical Thinning in Elderly Population

Impact of renal impairment on short-term outcomes following endovascular thrombectomy for acute ischemic stroke: A systematic review and meta-analysis

BACKGROUND

The impact of renal impairment on the outcomes of patients with acute ischemic stroke treated with endovascular thrombectomy was relatively limited and contradictory. We performed a systematic review and meta-analysis to investigate this.

AIMS

We registered a protocol in September 2020 and searched MEDLINE, EMBASE, and Google Scholar accordingly. Renal impairment was defined as an estimated glomerular filtration rate <60 mL/min/1.73 m². Predefined outcomes included functional independence (defined as a modified Rankin Scale of 0, 1, or 2) at three months, successful reperfusion, mortality, and symptomatic intracerebral hemorrhage.

SUMMARY OF REVIEW

Eleven studies involving 3453 patients were included. For the unadjusted outcomes, renal impairment was associated with fewer functional independence (odds ratio (OR), 0.49; 95% confidence interval (CI), 0.39-0.62) and higher mortality (OR, 2.55; 95% CI, 2.03-3.21). Renal impairment was not associated with successful reperfusion (OR, 0.80; 95% CI 0.63-1.00) and symptomatic intracerebral hemorrhage (OR, 1.41; 95% CI, 0.95-2.10). For the adjusted outcomes, results derived from a multivariate meta-analysis were consistent with the respective unadjusted outcomes: functional independence (OR, 0.59; 95% CI, 0.45-0.77), mortality (OR, 2.23, 95% CI, 1.45-3.43), and symptomatic intracerebral hemorrhage (OR, 1.34; 95% CI, 0.85-2.10).

CONCLUSIONS

We presented the first systematic review to demonstrate that renal impairment is associated with fewer functional independence and higher mortality. Future endovascular thrombectomy studies should publish complete renal estimated glomerular filtration rate data to facilitate prognostic studies and permit estimated glomerular filtration rate to be analyzed in a continuous variable.Systematic Review Registration: PROSPERO CRD42020191309.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Retinal neurovascular changes in chronic kidney disease

PURPOSE

To examine retinal neurovascular changes in patients with chronic kidney disease (CKD).

METHODS

Case-control study. A total of 171 CKD cases and 40 controls were recruited (mean age 62.9 ± 10.3 versus 60.8 ± 9.2, p = 0.257). Retinal neural parameters, including parafoveal retinal thickness (PfRT), macular ganglion cell complex thickness (GCCt), global loss volume (GLV), focal loss volume (FLV) and peripapillary retinal nerve fibre layer thickness (RNFLt), were measured using optical coherence tomography (OCT). Microvascular parameters, including foveal avascular zone size, vessel density over the parafoveal superficial vascular plexus (SVP-VD), parafoveal deep vascular plexus (DVP-VD) and radial peripapillary capillary (RPC-VD), were measured using OCT angiography.

RESULTS

Chronic kidney disease (CKD) patients showed reduced PfRT, GCCt and RNFLt and increased GLV and FLV compared with the controls (all p < 0.005). Among patients with CKD, estimated glomerular filtration rate was an independent factor associated with PfRT (coefficient 0.19, p = 0.015), GCCt (coefficient 0.10, p = 0.006), GLV (coefficient - 0.08, p = 0.001), FLV (coefficient - 0.02, p = 0.006) and RNFLt (coefficient 0.15, p = 0.002). Parafoveal retinal thickness (PfRT), GCCt, GLV, FLV and RNFLt were correlated with SVP-VD (all p < 0.001) but not with DVP-VD (all p > 0.1).

CONCLUSIONS

Chronic kidney disease (CKD) patients demonstrated a significant reduction in macular thickness and changes in retinal neural parameters. These changes were associated with the severity of CKD and correlated with the microvascular rarefaction in the parafoveal SVP.

Homocysteine and age-associated disorders

There are numerous theories of aging, a process which still seems inevitable. Aging leads to cancer and multi-systemic disorders as well as chronic diseases. Decline in age- associated cellular functions leads to neurodegeneration and cognitive decline that affect the quality of life. Accumulation of damage, mutations, metabolic changes, failure in cellular energy production and clearance of altered proteins over the lifetime, and hyperhomocysteinemia, ultimately result in tissue degeneration. The decline in renal functions, nutritional deficiencies, deregulation of methionine cycle and deficiencies of homocysteine remethylation and transsulfuration cofactors cause elevation of homocysteine with advancing age. Abnormal accumulation of homocysteine is a risk factor of cardiovascular, neurodegenerative and chronic kidney disease. Moreover, approximately 50% of people, aged 65 years and older develop hypertension and are at a high risk of developing cardiovascular insufficiency and incurable neurodegenerative disorders. Increasing evidence suggests inverse relation between cognitive impairment, cerebrovascular and cardiovascular events and renal function. Oxidative stress, inactivation of nitric oxide synthase pathway and mitochondria dysfunction associated with impaired homocysteine metabolism lead to aging tissue degeneration. In this review, we examine impact of high homocysteine levels on changes observed with aging that contribute to development and progression of age associated diseases.

Effects of sex, educational background, and chronic kidney disease grading on longitudinal cognitive and functional decline in patients in the Japanese Alzheimer's Disease Neuroimaging Initiative study

Introduction

The objective of this study was to determine whether sex or education level affects the longitudinal rate of cognitive decline in Japanese patients in the Alzheimer's disease Neuroimaging Initiative study with defined mild cognitive impairment (MCI).

Methods

We accessed the entire Japanese Alzheimer's Disease Neuroimaging Initiative data set of 537 individuals, among whom 234 had MCI and 149 had Alzheimer's disease. We classified participants into three categories of educational history: (1) low, 0 to 9 years; (2) moderate, 10 to 15 years; and (3) high ≥16 years. We examined the main effects and interactions of visit, sex, and educational achievement on scores for the Clinical Dementia Rating Sum of Boxes, Alzheimer's Disease Assessment Scale–cognitive subscale 13, Mini-Mental State Examination, and Functional Activities Questionnaire in a longitudinal manner.

Results

Women with MCI had a significantly faster rate of decline than men over a 3-year period. Highly educated men showed a significantly slower rate of decline than the other groups. Sex differences in the rates of decline remained after stratification by amyloid or apolipoprotein E (APOE) ε4 status but were absent in Alzheimer's disease over a 2-year period. Subtle differences in chronic kidney disease grade affected the rate of decline. A higher Fazekas periventricular hyperintensity score was associated with a lower estimated glomerular filtration rate in women only.

Discussion

In patients with MCI, sex and educational history significantly affected the rate of change in cognitive and clinical assessments. Furthermore, a subtle decline in chronic kidney disease grade was associated with a faster rate of decline regardless of amyloid pathology in women.