Structural and Functional Alterations in Hemodialysis Patients: A Voxel-Based Morphometry and Functional Connectivity Study

Abstract

Structural and functional brain alterations have been always observed in end-stage renal disease (ESRD) patients undergoing hemodialysis. The present study aimed to investigate the gray matter volume (GMV) changes in hemodialysis patients compared with those noted in healthy subjects, as well as explore the associated functional connectivity alterations based on the abnormal GMV regions. The experiments revealed the effects of regional morphometry aberrance on the brain functional integrity. A total of 46 hemodialysis patients (53.11 ± 1.58 years, 28 males) and 47 healthy subjects (55.57 ± 0.86 years, 22 males) were enrolled in the present study. All subjects underwent high-resolution T1-weighted imaging, resting-state functional MR imaging, and laboratory examinations were performed in hemodialysis patients. The GMV deficits were analyzed using voxel-based morphometry (VBM) and regions with GMV alteration were defined as seeds for functional connectivity analysis. Correlation analyses between significantly different regions and the results of the blood examination were further performed. We found that bilateral thalamus exhibited significantly increased volumes in the hemodialysis patients compared with those of the healthy subjects. However, the bilateral rectus, bilateral caudate, and bilateral temporal gyrus demonstrated significantly decreased volumes. When the regions with GMV alterations were defined as seeds, the hemodialysis patients exhibited decreased integrations in the thalamo-cortical network and within the basal-ganglia connection. The present study revealed the presence of different types of structural and functional brain impairments in hemodialysis patients.

Changes in the Shape and Volume of Subcortical Structures in Patients With End-Stage Renal Disease

“…We also detected atrophy of the left hippocampus, albeit without Bonferroni correction. However, in contrast, it is different from our research results, and a recent study found significantly higher bilateral thalamus volumes in hemodialysis patients compared with HCs, although their results on the caudate and amygdala volumes were similar to our observations ( Jin et al, 2020 ). Previous researchers found that compared with HCs, patients with minimal nephro-encephalopathy ESRD had lower brain volumes of the right amygdala and hippocampus, and those with non-nephro-encephalopathy ESRD had higher brain volumes of the right caudate and right thalamus ( Zhang et al, 2013 ).…”

“…These different findings are likely related to differences in study patients and methods used. For example, some researchers used VBM to analyze subcortical volumes instead of the volumetric analysis methods used in our study ( Prohovnik et al, 2007 ; Zhang et al, 2013 ; Jin et al, 2020 ). Moreover, our study subjects differed from those of previous studies; the previous study selected patients with ESRD with non-nephro-encephalopathy, whereas the patients in our study had general cognitive and sleep disorders ( Zhang et al, 2013 ).…”

“…Therefore, different degrees of subcortical structural volume abnormalities are often observed in patients with ESRD. Although studies investigating these alterations have been conducted, results are inconsistent ( Zhang et al, 2013 ; Chang et al, 2017 ; Jin et al, 2020 ). Recently, subcortical structural atrophy was reported in patients with ESRD who had been treated using hemodialysis ( Prohovnik et al, 2007 ; Chiu et al, 2019 ).…”

Changes of Brain Functional Connectivity in End-Stage Renal Disease Patients Receiving Peritoneal Dialysis Without Cognitive Decline

“…The patients in our study displayed lower between-network connectivity at the cingulate and postcentral gyri in SN, while insula-thalamus connectivity was clearly increased in the patients with ESRD receiving PD ( Table 3 ), which has never been reported before. In contrast, a recent study that focused on patients receiving HD found hypo-connectivity in the thalamo-cortical network ( 16 ). Based on the observations, the SN could be a potential network susceptible to the changes of between-network connectivity in the patients with ESRD receiving PD; however, further investigation is needed to delineate whether dialysis modalities affect the patterns of connectivity alterations.…”

“…Earlier, R-fMRI studies of patients with ESRD found decreased brain regional activity in a diffuse pattern over bilateral frontal, parietal, and temporal lobes, or impaired default-mode network (DMN) connectivity in the posterior cingulate cortex, precuneus, and medial prefrontal cortex (11,12), without mention of dialysis modality. Subsequent studies have identified different aspects of connectivity reduction in patients with ESRD (13)(14)(15)(16). Zheng et al observed the decreased connectivity to be predominantly related to the prefrontal lobe in patients with ESRD receiving hemodialysis (HD), which involves planning complex cognitive behavior (13).…”