Imaging Study On Laparoscopic Sleeve Gastrectomy Induced Sustained Alterations In Structures And Functions In Obese Patients Patientsconnectivity In Obese Patients

Obesity is a pervasive public health problem,and it not only causes a variety of metabolic diseases,but also has adverse effects on the central nervous system.Currently,there are many treatments to control and regulate weight.Laparoscopic sleeve gastrectomy(LSG)has a long-term effective effect on the treatment of obesity,which can cause sustained and significant weight loss.Neuroimaging studies have shown that LSG induced the recovery of both brain structures and functions in obese patients while reducing weight.However,the association between brain structural and functional changes caused by LSG is unclear.In addition,no current study has examined multiple time points post-LSG to investigate if LSG could induce sustained changes of brain structures and functions.Therefore,research is still needed to prove whether LSG-induced structural changes are accompanied by functional alterations,and whether LSG can induce sustained or stable recovery of brain structures and functions.This research was based on 3D structural and resting state functional magnetic resonance imaging(MRI)technology that utilized imaging data and clinical measurements data of obese participants at pre-LSG,1-month and 3-month-post-LSG.One-way within-subject repeated measures ANOVA was employed to assess LSG-induced sustained changes of brain structures and functions in obese patients,and then the association between brain structural and functional changes caused by LSG were assessed,so as to reveal the mechanism of regulating weight by LSG.(1)3D structural MRI and voxel-based morphometry analysis were employed to investigate sustained changes of brain gray matter(GM)and white matter(WM)volumes caused by LSG in obese patients.Results showed that LSG sustainably increased GM and WM volumes in brain regions associated with reward(Caudate),interoception(INS),self-referential processing(PCC),executive control(ACC,IFG)and memory(PHIPP).BMI was negatively correlated with GM volume in the caudate at pre-LSG,1-month and 3-month post-LSG.GM volumes in the INS and PCC showed positive correlations at 1-month and 3-month post-LSG.Resting state functional connection(RSFC)analysis with the INS and PCC as seeds found that LSG sustainably increased RSFC strengths of the INS-PCC,and sustainably decreased RSFC strength of the PCC-DMPFC.In addition,GM volumes in the INS and PCC were positively correlated with RSFC strengths of the INS-PCC at 1-month post-LSG,GM volume in the INS was positively correlated with RSFC strengths of the INS-PCC at 3-month post-LSG,indicating that LSG-induced structural changes were closely related to RSFC changes.(2)Amplitude of low frequency fluctuation(ALFF)analysis was employed to investigate sustained changes in brain resting state activity caused by LSG in obese patients.Results showed that LSG sustainably decreased activity in brain regions associated with reward(VTA)and control of food-intake(THA),and sustainably increased activity in brain regions associated with executive control(IFG)and somatosensory processing(Post Central).In addition,ALFF values in the VTA and THA showed positive correlations at pre-LSG,1-month and 3-month post-LSG.The changes in ALFF values in the VTA and THA also showed positive correlations at 1-month and 3-month post-LSG as compared to pre-LSG,and between 1-month and 3-month post-LSG.Based on the special correlation between activities of the VTA and THA,RSFC analysis with the VTA and THA as seeds was performed.Research found that LSG sustainably increased RSFC strengths of the VTA-THA.(3)The regions with differences in GM volume and resting state activity(ALFF value)were defined as regions of interest(ROIs),and a pair-wise functional connection was employed to investigate sustained changes of RSFC between the regions with differences in structures and functions caused by LSG in obese patients.Research found that LSG sustainably increased RSFC involving interoception and self-referential processing(INS_R-PCC_R),reward circuits(VTA_R-Caudate_L),interoception and executive control(IFG_L-INS_R).These results indicated that LSG not only promoted sustained improvement of brain structure and function,it also caused sustained recovery of the RSFC between regions with differences in GM volume and resting state activity.In the current longitudinal follow-up study,we found that LSG caused sustained changes in brain structures,functions and RSFC in obese patients,which revealed the long-term benefits of LSG-induced sustained neuroplastic recovery,and provided imaging evidence for revealing the central regulation mechanism of bariatric surgery.The current study will provide clinical and theoretical support for longer-term effective weight loss and non-invasive non-operative treatment of obese patients.