The Change Of Serum High Density Lipoprotein Cholesterol In Patients With Major Depressive Disorder And Its Neural Effects

Background and purpose:There is evidence that major depressive disorder(MDD)is related to serum lipid level alterations.However,the neural correlates underlying this association remain poorly understood.The purpose of this study is to explore the serum lipid alterations and its neural effects in patients with MDD.Methods:Forty-nine MDD patients and fifty healthy controls received structural,resting-state functional and diffusion tensor magnetic resonance imaging(MRI).Voxel-based morphometry(VBM),functional connectivity(FC)and tract-based spatial statistics(TBSS)analyses were performed to assess gray matter structure,function and white matter integrityrespectively.Peripheral venous blood samples were collected to measure serum levels of lipid profiles including total cholesterol(TC),triglyceride(TG)and high density lipoprotein cholesterol(HDL-C).Correlation and mediation analyses were conducted to investigate the associations of serum lipid levels with brain imaging parameters in MDD patients and healthy controls respectively.Results:Compared with healthy controls,serum HDL-C level in patients with MDD is lower(P< 0.05).The serum HDL-C level was positively correlated with gray matter volume(GMV)in the ventromedial prefrontal cortex and micro-structural integrity in multiple white matter regions,whilenegatively correlated with the FC of the with-default mode network in MDD patients.Moreover,the within-default mode network FC mediated the relationship between GMV in the ventromedial prefrontal cortex and serum HDL-C level;white matter integrity in the genu of corpus callosumwas a mediator of the association between serum HDL-C level and depressive symptom severity in MDD patients.In healthy controls,we did not observe any correlations between GMV,FC,white matter integrity and serum lipids level.Conclusion:These findings indicate the lower HDL-C level and its correlations with brain structure and functions in patients with MDD,which may help us to further understand the neural effects of lower HDL-C level in MDD.