Brain white matter structural networks in patients with non-neuropsychiatric systemic lupus erythematosus

Abstract

Previous neuroimaging studies have revealed cognitive dysfunction in patients with systemic lupus erythematosus (SLE) and suggested that it may be related to disrupted brain white matter (WM) connectivity. However, no study has examined the topological properties of brain WM structural networks in SLE patients, especially in patients with non-neuropsychiatric SLE (non-NPSLE). In this study, we acquired DTI datasets from 28 non-NPSLE patients and 24 healthy controls, constructed their brain WM structural networks by using a deterministic fiber tracking approach, estimated the topological parameters of their structural networks, and compared their group differences. We reached the following results: 1) At the global level, the non-NPSLE patients showed significantly increased characteristic path length, normalized clustering coefficient and small-worldness, but significantly decreased global efficiency and local efficiency compared to the controls; 2) At the nodal level, the non-NPSLE patients had significantly decreased nodal efficiency in regions related to movement control, executive control, and working memory (bilateral precentral gyri, bilateral middle frontal gyri, bilateral inferior parietal lobes, left median cingulate gyrus and paracingulate gyrus, and right middle temporal gyrus). In addition, to pinpointing the injured WM fiber tracts in the non-NPSLE patients, we reconstructed the major brain WM pathways connecting the abnormal regions at the nodal level with the corticospinal tract (CST), superior longitudinal fasciculus-parietal terminations (SLFP), and superior longitudinal fasciculus-temporal terminations (SLFT). By analyzing the diffusion parameters along these WM fiber pathways, we detected abnormal diffusion parameters in the bilateral CST and right SLFT in the non-NPSLE patients. These results seem to indicate that injured brain WM connectivity exists in SLE patients even in the absence of neuropsychiatric symptoms.

Longitudinal evaluation of diffusion tensor imaging and cognition in systemic lupus erythematosus

“…Results similar to ours were reported in a recent DTI study showing that non-NP SLE patients had widespread reduction in brain connectivity even with no NP symptoms. 53 Other data supporting this notion come from our study of SLE patients who had increased cortical activation on functional MRI during the performance of working memory and executive function tasks, interpreted as evidence of compensatory cortical activation in the presence of early WM neuropathology. 40 The strengths of this study include the first use of DTI and neuropsychological testing in SLE using a longitudinal design, careful patient selection to exclude any NP SLE or other major disorders, and thorough medical surveillance.…”

Altered Amplitude of Low-Frequency Fluctuations in Inactive Patients with Nonneuropsychiatric Systemic Lupus Erythematosus

“…Bernardo et al [59] revealed that SLE patients with memory impairment showed reduced cortical thickness in the precentral gyrus when compared to the SLE patients without memory deficits. Previous diffusion tensor imaging study demonstrated lower fractional anisotropy in the precentral gyrus in SLE patients [60]. Sensorimotor network (SMN), including the postcentral gyrus and precentral gyrus, is one of the earliest resting brain network proposed in the fMRI study [16].…”

White matter hyperintensities associate with cognitive slowing in patients with systemic lupus erythematosus and neuropsychiatric symptoms

“…27 Only a limited number of studies have previously focused on the association between cognitive function and brain volumes on MRI in patients with SLE without major nervous system involvement ('non-NPSLE'). [28][29][30][31][32][33][34][35][36][37] Several studies found an association between global cognitive impairment and reduced grey matter 36 or white matter volume 28 30 36 and in one study this association was not found. 31 In our study, we demonstrated that brain volumes were indeed associated with cognitive function (all domains) in patients with SLE, but differences were present between NPSLE phenotypes.…”