Regional And Networks Characteristic Of Brain Glucose Metabolic Networks In Healthy And Type2Diabetes Mellitus Subjects

In the first part of the present study, we investigate the gender differences of regional brain glucose metabolism and glucose metabolic networks. Subsequently, in the second part of this study, we investigate whether altered regional cerebral glucose metabolism, metabolic connectivity, and topological organization exist in type2diabetes mellitus.Part Ⅰ. Regional and networks characteristic of brain glucose metabolic networks in healthy subjectsSection1. Gender differences of brain glucose metabolic networks revealed by FDG-PET:Evidence from a large cohort of400young adultsPurpose:To investigate the gender difference in human brain glucose metabolic networks.Materials and Methods:FDG PET data of400right-handed, healthy subjects were obtained and analyzed in the study. We first investigated the regional differences of brain glucose metabolism between genders. Subsequently, we investigated the gender differences of the metabolic networks.Results:Compared with the males, females showed higher metabolism in the posterior part and lower metabolism in the anterior part of the brain. In addition, significant gender differences within and between brain glucose metabolic networks were revealed in the present study.Conclusion:This study provides solid data that reveal gender differences in regional brain glucose metabolism and brain glucose metabolic networks. Section2. Small-worldness and gender differences of large scale brain metabolic covariance networks in young adults:A FDG PET study of400subjectsBackground:To investigate the small-worldness and the gender differences in the topological architectures of human brain metabolic networks.Materials and methods:FDG-PET data of400healthy right-handed subjects were involved in the present study. Metabolic networks of each gender were constructed by calculating the covariance of regional cerebral glucose metabolism (rCMglc) across subjects. Gender differences of network and nodal properties were investigated by using the graph theoretical approaches.Results:We found prominent small-world properties in the domain of metabolic networks in each gender. No significant gender difference in the global characteristics was found. Gender differences of nodal characteristic were observed in a few brain regions. We also found bilateral and lateralized distributions of network hubs in the females and males. Furthermore, we first reported that some hubs of a gender located in the brain regions showing weaker rCMglc in this gender than the other gender.Conclusion:The present study demonstrated that small-worldness was existed in metabolic networks, and revealed gender differences of organizational patterns in metabolic network. Part Ⅱ. Regional and networks characteristic of brain glucose metabolic networks in type2diabetes mellitus subjectsSection1. Altered regional brain glucose metabolism and glucose metabolic network in type2diabetes:A FDG PET studyPurpose:To investigate whether altered regional cerebral glucose metabolism and glucose metabolic networks existed in type2diabetes mellitus subjects.Materials and Methods:113type2diabetes mellitus subjects and195non-diabetic age-and gender-matched control subjects were involved in this study. First, we investigated the regional differences of brain glucose metabolism between2groups. Second, we detected the relationship between regional brain glucose metabolism of each voxel and clinical data. Finally, we tested the differences within brain networks between2groups.Results:Compared with control group, the diabetes group showed lower metabolism in most of the cerebral cortex, and higher metabolism in bilateral cerebellum. We observed the regional brain glucose metabolism of some specific regions was correlated with clinical data in type2diabetes mellitus. Moreover, significant differences within brain metabolic networks were revealed between2groups in the present study.Conclusion:The present study provides solid data that demonstrate abnormal regional brain glucose metabolism and glucose metabolic network in type2diabetes. Section2. Altered topological properties of large scale brain metabolic covariance networks in type2diabetes:A FDG PET study of308subjects Purpose:To investigate whether altered topological architecture of brain metabolic networks existed in type2diabetes mellitus subjects.Materials and Methods:FDG PET data of308right-handed subjects were involved in this study. We compared the global characteristics and nodal characteristics of the brain metabolic networks between type2diabetes and control group. Moreover, the metabolic network hubs of2groups were calculated for observing the altered distributional pattern of network hubs in type2diabetes.Results:We found prominent small-world properties in the brain metabolic covariance networks of type2diabetes group. No significant group difference in the global characteristics was found after correction. However, significant differences of nodal characteristic were found in a few brain regions between2groups. Furthermore, altered distributional patterns of network hubs were observed in type2diabetes group.Conclusion:The present study revealed the small-worldess, and demonstrated altered topological architectures in large scale brain metabolic covariance networks of type2diabetes.