A deeper understanding of the body’s fat storage and its changes in response to overeating is key to this recent study. Researchers explored how the enlargement of fat cells, particularly beneath the skin, is not just a simple response to excess energy, but varies from person to person, impacting one’s metabolic health. This condition, known as adipose tissue hypertrophy, emerges as a critical factor in understanding individual health variations despite similar body fat levels.
The research, led by Professor André C. Carpentier at Université de Sherbrooke with his colleagues there, Dr. Run Zhou Ye, Dr. Emilie Montastier, Dr. Frédérique Frisch, Christophe Noll, Professor Hugues Allard-Chamard and Professor Nicolas Gévry, together with Professor André Tchernof of the Québec Heart and Lung Research Institute at Laval University, is a step forward in clarifying how adipocyte size relates to postprandial fat handling in the body. Using a combination of body metabolism tests and advanced cellular study techniques, the team studied 40 men and women, nearly all with either normal or impaired blood sugar tolerance. In people with larger fat cells under the skin of the belly, the heart took up more fat after a meal, and more of the fat from the meal was stored in the deep belly fat around the organs, while less reached lean organs such as the liver. These links did not depend on how much body fat people had.
Professor Carpentier explained, “Adipocyte hypertrophy potentially leads to both pathogenic and adaptive changes in lean organ fatty acid uptake, that variably impact the heart and the liver over the entire postprandial period.”
Examining fat tissue cell by cell in two of the participants, matched for sex, body mass index, body fat and waist size but with very different fat cell sizes, brought to light substantial shifts in gene activity associated with adipocyte hypertrophy. This approach offered a fresh perspective on how changes in fat cells relate to the body’s overall metabolism.
“Our results highlight significant shifts in cell populations and differentiation trajectories with adipose tissue hypertrophy that are consistent with systemic and adipose tissue insulin resistance and postprandial abnormalities of fatty acid metabolism from metabolic testing,” Professor Carpentier noted.
The research is relevant to common health problems such as obesity and diabetes, because it links fat cell size to differences in how the body handles fat after a meal, even among people with similar amounts of body fat.
Because the cell-by-cell analysis is costly, it was done in only two people; the researchers note that more affordable methods could make it possible for all participants in the future. Fat from deeper regions of the body, such as around the organs, was not sampled.
In conclusion, this comprehensive study provides a deeper understanding of the role of adipocyte hypertrophy in postprandial fatty acid metabolism, highlighting the intricate processes within our fat tissue and their possible links to health. The findings add to scientific knowledge of how fat tissue affects metabolism.
Journal Reference
Ye RZ, Montastier E, Frisch F, Noll C, Allard-Chamard H, Gévry N, Tchernof A, Carpentier AC. Adipocyte hypertrophy associates with in vivo postprandial fatty acid metabolism and adipose single-cell transcriptional dynamics. iScience. 2024;27(1):108692. DOI: https://doi.org/10.1016/j.isci.2023.108692
About the Authors
André C. Carpentier is the Canada Research Chair in Molecular Imaging of Diabetes and professor and endocrinologist-lipidologist in the Departments of Medicine, Faculty of Medicine and Health Sciences at the Université de Sherbrooke. He is the Scientific Director of the Centre de recherche du CHUS since December 2020. He is the scientific co-lead of Diabetes Action Canada ( https://diabetesaction.ca/). His research interests include: 1) the role of postprandial fatty acid metabolism in the development of type 2 diabetes and cardiovascular diseases; 2) the investigation of brown adipose tissue metabolism in humans; and 3) the anti-diabetic mechanisms of bariatric surgery. Since 2007, Dr. Carpentier received >$7.9M in operating funds and >$29M in infrastructure and network funds as PI, and >$24.5M as co-PI, >$1M of which was attributed directly to his lab. Dr. Carpentier has published more than 184 peer-reviewed manuscript publications cited over 19,000 times (H index 59). He has trained 30 undergraduate, 19 graduate and 15 postdoctoral students, some of whom are currently pursuing their own successful independent research careers. He is the recipient for multiple awards, including the 2011 Diabetes Young Investigator Award of the Canadian Society of Endocrinology and Metabolism, the CDA/CIHR Young Investigator Award in 2012 and the Canadian Lipoprotein Conference Physician-Scientist Award in 2014. He has been elected Fellow of the Canadian Academy of Health Sciences (FCAHS, 2015). André Carpentier, MD Curriculum vitae PAGE 2
André Tchernof is Professor at Laval University School of Nutrition since 2000. After a Bachelor's degree in Biochemistry (1991), a Master’s degree (1992) and a Doctoral degree (1996) in Physiology-Endocrinology at Laval University, he trained as a postdoctoral fellow in Molecular Endocrinology (Laval University Medical Center, 1996-97) and in Endocrinology & Metabolism at the University of Vermont (1997-2000). He is co-director of the Research Chair in Bariatric and Metabolic Surgery and Obesity Tissue Biobank at the Quebec Heart and Lung Institute. He is currently the Principal Investigator of a Canadian Institutes of Health Research training platform grant on obesity, metabolism, and diabetes called MyRoad (Maximize Your Research on Obesity and Diabetes) and the Cardiometabolic Health, Diabetes and Obesity Network (CMDO) funded by the Fonds de recherche du Québec en santé. He contributed to more than 250 publications in peer-reviewed journals. His research interests relate to the metabolic complications of obesity and body fat distribution, with a particular emphasis on adipose tissue physiology. Experimental approaches combine cellular biology techniques with biochemistry, genomics, transcriptomics and clinical investigation in humans, including the impact of bariatric surgery. His research allows clinical observations to be linked with the cellular characteristics or mechanisms underlying pathophysiological conditions such as abdominal obesity and related cardiometabolic complications.
