Abstract
Objectives:
Cognitive dysfunction (CD) and depression are interlinked comorbidities of SLE. They may be the
result of altered brain mechanisms. This study aimed to examine SLE effects on functional
connectivity (FC) within the default mode network (DMN) using resting state fMRI – and how
depression may impact this.
Methods:
Demographic, clinical and psychiatric data were collected from 19 SLE-active, 23 SLE-stable and 30
healthy controls (HC) participants. A T2*-weighted rsfMR scan was acquired and analysed using
independent component analysis (ICA). Group z-scores for nodes associated with the DMN were
tested. Significant nodes were entered into a factor analysis. The combined factor was used in
correlations with factors of interest. Significant variables were used in a mediation analysis.
Results:
14 DMN nodes were defined using ICA. In five nodes, the SLE groups had significantly reduced FC
compared to the HC group (
p<0.01). Factor analysis generated one factor that only depression score
correlated with for both the HC group (
rs=-0.510) and SLE groups combined (
rs=-0.390). Mediation
analysis revealed depression score accounted for 22% of the altered FC in the DMN. Disease state
accounted for the remaining 78%.
Conclusions:
Altered FC was evident in DMN nodes for SLE groups irrespective of disease activity. Depression
accounts for some of this effect but SLE directly accounted for more. Further studies are needed to
assess if these changes may be a precursor to CD in SLE. If so, rs-fMRI could be an early marker for
CD in SLE and help in future CD in SLE treatment trials.
Cognitive dysfunction (CD) and depression are interlinked comorbidities of SLE. They may be the
result of altered brain mechanisms. This study aimed to examine SLE effects on functional
connectivity (FC) within the default mode network (DMN) using resting state fMRI – and how
depression may impact this.
Methods:
Demographic, clinical and psychiatric data were collected from 19 SLE-active, 23 SLE-stable and 30
healthy controls (HC) participants. A T2*-weighted rsfMR scan was acquired and analysed using
independent component analysis (ICA). Group z-scores for nodes associated with the DMN were
tested. Significant nodes were entered into a factor analysis. The combined factor was used in
correlations with factors of interest. Significant variables were used in a mediation analysis.
Results:
14 DMN nodes were defined using ICA. In five nodes, the SLE groups had significantly reduced FC
compared to the HC group (
p<0.01). Factor analysis generated one factor that only depression score
correlated with for both the HC group (
rs=-0.510) and SLE groups combined (
rs=-0.390). Mediation
analysis revealed depression score accounted for 22% of the altered FC in the DMN. Disease state
accounted for the remaining 78%.
Conclusions:
Altered FC was evident in DMN nodes for SLE groups irrespective of disease activity. Depression
accounts for some of this effect but SLE directly accounted for more. Further studies are needed to
assess if these changes may be a precursor to CD in SLE. If so, rs-fMRI could be an early marker for
CD in SLE and help in future CD in SLE treatment trials.
| Original language | English |
|---|---|
| Journal | Rheumatology |
| Publication status | Accepted/In press - 10 Sept 2021 |