| Part:1 Large-scale brain networks changes in diabetic retinopathy patientsObjective: diabetic retinopathy(DR)is a serious diabetic retinal microvascular complication.DR patients are at increased risk for cognitive decline and dementia.Previous imaging studies have shown that DR patients are associated with changes in brain function and structure and are associated with cognitive impairment.However,the changes in functional connectivity of large-scale resting-state networks(RSNs)in DR patients are unclear.In this study,(1)independent component analysis(ICA)was used to analyze RSN changes in DR patients.(2)FNC(functional network connectivity)analysis was conducted to investigate the interaction between these RSNs.Materials and methods: 34 non-proliferative DR patients(18 males and 16females;Mean age: 53.53±8.67 years)and 38 normal controls(15 males and 23females;Mean age: 48.63±11.83 years)were enrolled in the eye center renmin hospital of wuhan university.All subjects underwent the MRI(GE Discovery MR7503.0T)scanning at rest.ICA method was used to extract 9 RSNs.(1)Two-sample t test was conducted to investigate 9 different network FCs in RSNs between the two groups.(2)The FNC analysis was used to evaluate the interaction between these RSNs.(3)Pearson correlation analysis was used to investigate the relationship between network FC values and clinical variables in the DR group.Results:(1)Compared with HC group,DR patients had significant decreased FC within the basal ganglia network(BGN),visual network(VN),ventral default mode network(v DMN),right executive control network(r ECN),salience network(SN),left executive control network(l ECN),auditory network(AN),dorsal default mode network(d DMN).(2)FNC analysis showed that DR patients showed the increased functional connections of VN-BGN,VN-v DMN,VN-d DMN,v DMN-l ECN,SNBGN,l ECN-d DMN and AN-BGN FNCs relative to HC group.(3)hemoglobin a1 c in DR patients was positively correlated with the FC value of right CAU(r = 0.414,P =0.015).There was a negative correlation between LDL and FC values of bilateral MOG(r =-0.353,P = 0.041).There was a negative correlation between LDL and FC values of bilateral Pre CUN in DR patients(r=-0.356;P =0.039);Total cholesterol in DR patients was negatively correlated with FC value of left STG(r =-0.407,P =0.017).Conclusion: our results revealed that DR patients had widespread deficits in both low-level perceptual and higher order cognitive networks,which suggest potential impairments in visual,auditory,and cognitive functions in DR patients.Our results provide useful information to better understand the neural mechanisms that affect DR patients.Part: 2 Topological organization of brain network changes in diabetic retinopathy patientsObjective: previous studies demonstrated that diabetic retinopathy(DR)patients were associated with large-scale functional brain network changes.However,alternations in the topological properties of the functional brain network in DR patients remain unknown.The aim of this study was to explore the topological organization of the functional brain network in DR patients using graph theory approaches.Materials and methods: 35 DR patients(18 males and 17 females,mean age:53.37±8.59 years)and 38 healthy controls(HCs)(18 males and 20 females,mean age:54.50±8.51 years),were enrolled in the eye center renmin hospital of wuhan university.All subjects underwent the MRI(GE Discovery MR750 3.0T)scanning at rest.Graph theory analysis was performed to investigate the topological properties of brain network at both global and nodal levels in DR patients.Results:(1)Both DR and HC groups showed high-efficiency small-world network in their brain functional networks.Compared with HC group,the DR group showed reduction in the clustering coefficient(P=0.0572)and local efficiency(P=0.0151).(2)Compared with HC group,the DR group showed reduced nodal centralities in the default-mode network(DMN)and increased nodal centralities in the visual network(VN)(P<0.01).(3)The DR group also showed abnormal functional connections among the VN,DMN,salience network(SN),and sensorimotor network(SMN).(4)Altered network metrics and nodal centralities were significantly correlated with visual acuity and fasting blood glucose level in DR patients.Conclusion: DR patients showed abnormal topological organization of the brain network.The DR group showed reduction in the local brain network efficiency,relative to HC group.Abnormal nodal centralities and functional disconnections were mainly located in the DMN,VN,SN,and SMN in DR patients.These findings offer important insight into the neural mechanism of visual loss and cognitive deficits in DR patients.Part:3 Functional network centrality alternations in diabetic retinopathy patientsBackground: previous studies demonstrated that diabetic retinopathy(DR)patients were associated with functional brain network changes.Whether the whole brain functional network centrality changes occur in DR patients remains unknown.The purpose of the study was to investigate the function network centrality changes in DR patients using voxel-wise degree centrality(DC)methods.Methods: 34 DR patients(18 males and 16 females)and 38 healthy controls(HCs)(18 males and 20 females)underwent resting-state magnetic resonance imaging scans.Two sample T test was conducted to compare different DC in voxel-wise between two groups.Results: compared with HCs,DR patients had significantly higher DC values in the pons and bilateral caudate and had significantly lower DC values in the left lingual and right lingual and right angular/middle occipital gyrus(MOG).The reduced DC of the left lingual showed closely correlation with the visual acuity and duration of DR patients.Conclusion: our results highlight that reorganization of the hierarchy of the functional connectivity network were related to visual network,default mode network and basal ganglia network,which might indicate the impaired top-down modulation and visuospatial and cognition in DR patients.The DC index can be used as a potential biomarker indicating the local network changes related to visual loss and dysglycemia in DR patients.Part:4 Cerebral blood flow alternations in diabetic retinopathy patientsBackground: previous studies demonstrated that diabetic retinopathy(DR)patients were associated with large-scale functional brain network changes.Whereas the resting cerebral blood flow(CBF)alterations specific to DR patients are not well understood.Our study was to explore CBF alterations in DR patients using pseudocontinuous arterial spin labeling(p CASL)imaging.Methods: 31 DR individuals(15 males and 16 females: mean age: 53.38±9.12years)and 33 health controls(HC)(12 males and 21 females;mean age: 51.61±9.84years)underwent arterial spin labelling magnetic resonance imaging.Two sample T test was conducted to compare different CBF in voxel-wise between two groups.Results: compared with HC group,DR patients exhibited significantly increased CBF values in the left middle temporal gyrus and the bilateral supplementary motor area and decreased CBF values in the bilateral calcarine and bilateral caudate.Moreover,the Hb A1c(%)level of DR patients showed a positive correlation with CBF values in the bilateral caudate(r=0.473,p=0.007).Conclusion: our results highlighted that DR patients had abnormal CBF values in the visual cortices,caudate,middle temporal gyrus and supplementary motor area,which might reflect vision and sensorimotor and cognition dysfunction in DR patients.These findings might help us to understanding the neural mechanism of DR patients. |
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