Specific fat-depots in obesity affect brain health: does all fat boil down to the same thing?

Obesity has been linked to functional and structural brain changes in neuroimaging studies. The exact mechanisms of how obesity may affect brain health are not well established, but proposed mechanisms include an important role of white adipose tissue (WAT) and cerebrovascular health.

PhD candidates Debby Vreeken and Florine Seidel studied the role of fat depot-specific effects on brain structure and function in adults with severe obesity enrolled in the BARICO (BAriatric surgery Rijnstate and Radboudumc neuroImaging and Cognition in Obesity) study. The research group, led by Amanda Kiliaan, department of Medical Imaging, Anatomy, in collaboration with the department of Bariatric Surgery, Rijnstate Hospital (Eric J Hazebroek) and Metabolic Health Research, TNO (Robert Kleemann) published the results in Neurology on 4 November 2022.

Within this cross-sectional study, brain structure, perfusion and cognitive function were measured before bariatric surgery (BS) using MRI and cognitive assessments. During BS, omental WAT (oWAT) and subcutaneous WAT (scWAT) depots were collected and analyzed by histopathology. oWAT is a type of visceral WAT and is often considered the bad guy, however their results surprisingly indicated more inflammation and enlarged fat cells in scWAT. The obtained datasets were then associated with brain structure and function. Although scWAT showed more inflammation and enlarged cells, scWAT was not associated with any of the brain readouts. Only oWAT was associated with cerebrovascular health. This relationship indicates an early stage of obesity-related effects on the brain.

At the moment, they are studying whether these early adverse effects of obesity on the brain are reversible by long-term sustainable weight loss in the same study population. In the end, they hope that their research contribute to the development of better health campaigns, healthcare, preventatives, and treatments to attenuate the impact of obesity.

Publication  

Impact of White Adipose Tissue on Brain Structure, Perfusion and Cognitive Function in Patients With Severe Obesity: The BARICO Study | Neurology Vreeken D, Seidel F, de La Roij G, Vening W, den Hengst WA, Verschuren L, Özsezen S, Kessels RPC, Duering M, Mutsaerts HJMM, Kleemann R, Wiesmann M, Hazebroek EJ, Kiliaan AJ. Impact of White Adipose Tissue on Brain Structure, Perfusion and Cognitive Function in Patients With Severe Obesity: The BARICO Study. Neurology. 2022 Nov 4:10.1212/WNL.0000000000201538. doi: 10.1212/WNL.0000000000201538. Epub ahead of print. PMID: 36332987.

Figure: Illustrative figure depicting CBF (left) and spatial CoV (right) maps. 

Top row, average CBF and spatial CoV maps of 6 participants with on average the lowest CBF in gray matter and the highest sCoV in gray matter from the total subjects studied. Bottom row, average CBF and spatial sCoV maps for 6 participants with on average the highest CBF in gray matter and the lowest sCoV in gray matter. 

Abbreviations: CBF = cerebral blood flow, sCoV = spatial coefficient of variation. 

Figure: Schematic summary of the main results 

Subcutaneous white adipose tissue (WAT) and omental WAT differ regarding morphology, inflammation and in their relation to adipokines and cerebrovascular health. Continuous lines show significant associations, dashed lines show unsignificant explored associations. 

Abbreviations: sCoV = spatial coefficients of variation, NAcc = nucleus accumbens, WAT = white adipose tissue, CRP = C-reactive protein, SAA = serum amyloid A, FPG = fasting plasma glucose.