Reversal of neurovascular decoupling and cognitive impairment in patients with end‐stage renal disease during a hemodialysis session: Evidence from a comprehensive fMRI analysis

Abstract

Neurovascular (NV) decoupling is a potential neuropathologic mechanism of cognitive impairment in patients with end‐stage renal disease (ESRD). Hemodialysis improves cognitive impairment at 24 h post‐dialysis, which suggests a potential neuroprotective effect of hemodialysis treatment on the brain. We investigated the effects of hemodialysis treatment on the reversal of NV decoupling associated with cognitive improvement. A total of 39 patients with ESRD and 39 healthy controls were enrolled. All patients were imaged twice during a dialysis session: before hemodialysis (T1 pre‐dialysis ) and at 24 h after dialysis (T2 post‐dialysis ). The healthy controls were imaged once. NV coupling was characterized based on correlation coefficients between four types of blood oxygen level‐dependent signals and cerebral blood flow (CBF). A battery of neuropsychological and blood tests was performed before the imaging. Patients with ESRD showed improvements in memory and executive function at T2 post‐dialysis compared with that at T1 pre‐dialysis . At both T1 pre‐dialysis and T2 post‐dialysis , patients with ESRD had lower amplitude of low‐frequency fluctuation (ALFF)–CBF coupling than healthy controls. Additionally, patients with ESRD had higher ALFF–CBF coupling at T2 post‐dialysis than at T1 pre‐dialysis . Higher memory scores, higher hemoglobin level, lower total plasma homocysteine level, lower systolic blood pressure variance, and lower ultrafiltration volume were associated with higher ALFF–CBF coupling in patients with ESRD after a hemodialysis session. These findings indicate that partial correction of anemia and hyperhomocysteinemia, stable systolic blood pressure, and fluid restriction may be closely linked to the reversal of NV decoupling and improvement in cognition in patients with ESRD.

Disruption of the white matter structural network in patients with hemifacial spasm and changes after microvascular decompression

“…Statistical analysis was performed using SPSS 25.0 software. The paired samples t-test was used to compare the preoperative and postoperative groups, while the independent samples t-test was used to compare the preoperative and postoperative groups with healthy controls (Li et al, 2023). Categorical variables were analyzed using the chi-square test.…”

The Role of Methionine-Rich Diet in Unhealthy Cerebrovascular and Brain Aging: Mechanisms and Implications for Cognitive Impairment

“…It is increasingly evident that dysfunction and damage within the cerebral microcirculation constitute significant contributors to age-related cognitive decline [17,29,[273][274][275][277][278][279]. Clinical investigations have furnished evidence suggesting that the consumption of a methionine-rich diet, coupled with hyperhomocysteinemia, can incite dysregulation in cerebral blood flow, directly impacting cognition [280][281][282][283]. Experimental studies have extended these clinical observations, providing valuable mechanistic insights into the synergistic interplay between the aging process and diet-induced accelerated cellular aging, particularly concerning cerebromicrovascular function [173,178,284].…”

“…Endothelial dysfunction induced by high-methionine diets or hyperhomocysteinemia can further disrupt neurovascular coupling by impairing the dilation of cerebral arterioles in response to neuronal activation [281,318]. Clinical and preclinical studies have reported associations between high methionine intake or hyperhomocysteinemia, dysregulation of cerebral blood flow, and cognitive dysfunction [173,178,280,[282][283][284]319].…”

Multiparameter neuroimaging study of neurovascular coupling changes in patients with end‐stage renal disease

“…Thus, the spatial correlation between CBF and a measure of local brain connectivity has been proposed as a surrogate index for NVC. Several studies have assessed NVC using two different indices, namely, the correlation between ASL and resting‐state functional magnetic resonance imaging (rs‐fMRI) at the global level and the ratio of perfusion and neural activity or brain connectivity at the regional level (Li et al., 2022 ; Li et al., 2023 ; Liang et al., 2013 ; Shang et al., 2022 ; Zhu et al., 2017 ). For example in a recent study, they investigated the four types of NVC between amplitude of low‐frequency fluctuation (ALFF), fractional ALFF, regional homogeneity, degree centrality, and CBF, and indicated that ESRD patients showed NVC dysfunction in global gray matter and multiple brain regions due to the mismatch between CBF and neural activity (Hu et al., 2024 ).…”