Abnormal topological parameters in the default mode network in patients with impaired cognition undergoing maintenance hemodialysis

Chuanlong Cao; Die Zhang; Wanqing Liu

doi:10.3389/fneur.2022.951302

Abnormal topological parameters in the default mode network in patients with impaired cognition undergoing maintenance hemodialysis

Front Neurol. 2022 Aug 18:13:951302. doi: 10.3389/fneur.2022.951302. eCollection 2022.

Authors

Chuanlong Cao^{1

2}, Die Zhang³, Wanqing Liu^{1

4}

Affiliations

¹ Department of Radiology, West China Second University Hospital, Sichuan University, Chengdu, China.
² Department of Radiology, Affiliated Xinhua Hospital of Dalian University, Dalian, China.
³ Department of Radiology, National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, The Second Affiliated Hospital, School of Medicine Southern University of Science and Technology, Shenzhen, China.
⁴ Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, China.

Abstract

Objective: The role of the default mode network (DMN) in the cognitive impairment experienced by patients with end-stage renal disease (ESRD) undergoing maintenance hemodialysis (MHD) remains unknown. This study tested the hypothesis that the topological architecture of the DMN plays a key role in ESRD-related cognitive impairment.

Methods: For this study, 43 ERSD patients receiving MHD and 41 healthy control (HC) volunteers matched for gender, age and education underwent resting-state functional magnetic resonance imaging examinations. DMN architecture was depicted by 20 selected DMN subregions. Graph theory approaches were applied to investigate multiple topological parameters within the DMN in resting state at the global, local and edge levels.

Results: Globally, the MHD group exhibited topological irregularities as indicated by reduced values for the clustering coeffcient (C_p), normalized C_p (γ), world-index (σ), and local effciency (E_loc) compared with the HC group. Locally, the MHD group showed greater nodal betweenness in the left retrosplenial cortex (RC) compared with the HC group. At the edge level, the MHD group exhibited disconnected resting-state functional connections (RSFCs) in the medial temporal lobe (MTL) subsystem including the ventral medial prefrontal cortex (VMPC)-left posterior inferior parietal lobule, VMPC-right parahippocampal cortex (PC), and right RC-left PC RSFCs. Additionally, the VMPC-right PC RSFC was positively correlated with the Digit Span Test score and E_loc, and the right RC-left PC RSFC was positively correlated with the Montreal Cognitive Assessment score and E_loc in the MHD group.

Conclusions: ESRD patients undergoing MHD showed local inefficiency, abnormal nodal centralities, and hypoconnectivity within the DMN, implying that the functional differentiation and local information transmission efficiency of the DMN are disturbed in ESRD. The disconnected RSFCs in the MTL subsystem likely facilitated topological reconfiguration in the DMN of ESRD patients, leading to impairments of multidomain neurocognition including memory and emotion regulation.

Keywords: default mode network; end-stage renal disease; functional connectivity; graph theory; resting-state fMRI.