Obesity and Brain Vulnerability in Normal and Abnormal Aging: A Multimodal MRI Study.

BACKGROUND: How the relationship between obesity and MRI-defined neural properties varies across distinct stages of cognitive impairment due to Alzheimer's disease is unclear. OBJECTIVE: We used multimodal neuroimaging to clarify this relationship. METHODS: Scans were acquired from 47 patients clinically diagnosed with mild Alzheimer's disease dementia, 68 patients with mild cognitive impairment, and 57 cognitively healthy individuals. Voxel-wise associations were run between maps of gray matter volume, white matter integrity, and cerebral blood flow, and global/visceral obesity. RESULTS: Negative associations were found in cognitively healthy individuals between obesity and white matter integrity and cerebral blood flow of temporo-parietal regions. In mild cognitive impairment, negative associations emerged in frontal, temporal, and brainstem regions. In mild dementia, a positive association was found between obesity and gray matter volume around the right temporoparietal junction. CONCLUSION: Obesity might contribute toward neural tissue vulnerability in cognitively healthy individuals and mild cognitive impairment, while a healthy weight in mild Alzheimer's disease dementia could help preserve brain structure in the presence of age and disease-related weight loss.

Preclinical models of disease and multimorbidity with focus upon cardiovascular disease and dementia.

The use of animal models is fundamental to furthering our understanding of human disease mechanisms, as well as identifying potential therapeutic targets. Diseases of ageing often involve multiple body systems; however, multi-systemic features are not fully recapitulated in the many of the animal models available. Therefore, combining pre-clinical models to better reflect the multimorbidities observed at the clinical level is critical. This review will highlight some of the key pre-clinical experimental models associated with cardiovascular (atherosclerosis, coronary heart disease), cerebrovascular (stroke, vascular dementia), metabolic (obesity, type-2 diabetes mellitus) and neurological (amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson's, epilepsy) diseases, and whether these models encompass known multimorbidities. In addition to this, we discuss established pre-clinical models that combine two or more conditions, within the context of dementia.