Does Inflammation Damage White Matter Tracts in Patients with Major Depression Open Access

Raj, Divyaansh (Spring 2020)

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Background: Major depressive disorder (MDD) is currently one of the most debilitating conditions in the world, affecting at least 20% of people at least once during their lifetimes. The pathophysiology of MDD is only beginning to be understood. Several studies have found inflammation be related to the clinical measures of depression severity and chronicity. Inflammation negatively impacts the white matter of the brain in several diseases of the central nervous system but whether inflammation-induced damage to white matter contributes to the pathophysiology of MDD has not been established.  

Goal: This study investigated whether white matter integrity is related to measures of disease chronicity and severity. Further, inflammatory cytokines interleukin six’s and C-reactive Protein’s correlation with white matter integrity was examined. This study also explored whether gender modulates the inflammation effect.

Methods: Diffusion Tensor Imaging (DTI) and Tract Based Spatial Statistics were conducted on 125 treatment-naïve patients to create generalized linear models (GLM) exploring the relationship between severity, chronicity, white matter integrity as measured by four common DTI indices, and inflammation.

Results: Results indicated significant negative correlations between white matter integrity and disease chronicity and severity, particularly in the corpus collosum, subgenual cingulate cortex (Brodmann Area 25), uncinate fasciculus, superior longitudinal fasciculus, and forceps minor. There were no significant correlations between IL6 or CRP and the DTI measures in the total sample set or male-female subgroups. Splitting the population into chronic and non-chronic patients revealed that in Brodmann Area 25 white matter integrity was decreased in chronic patients and increased in non-chronic patients.

Conclusions: These results suggest that white matter pathology contributes to the pathophysiology of depression and is related to the severity and chronicity of illness. Although there were no significant relationships between IL6 or CRP and DTI indices in the total sample, the results suggest that inflammation-induced white matter pathology may contribute to the disease process in MDD patients with a chronic course of illness.

Table of Contents

Abstract [8]

Background [10]

Methods [18]

Results [24]

Discussion [28]

Tables [35]

           Table 1       [35]

           Table 2       [36]

Figures [37]

           Figure 1      [37]

           Figure 2      [37]

           Figure 3- Consort Chart    [38]

Figure 4             [39]

Figure 5 & 6      [40]

Figure 7 & 8      [41]

Figure 9 & 10    [42]

Figure 11 & 12  [43]

Figure 13     [44]

Figure 14     [45]

Figure 15 & 16  [46]

References [48]

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