OnDemand: May 2024 Grand Rounds - Human Adipose Tissue Metabolism - What Happens with Obesity?-Human Adipose Tissue Metabolism

Video Transcription

Video Summary

Dr. Michael Jensen’s grand rounds presentation explored how human adipose tissue stores and releases energy, and why obesity affects people so differently. He compared “healthy” obesity with metabolically unhealthy central obesity, emphasizing that fat is an efficient energy reserve but must be tightly regulated. Normally, insulin suppresses fat breakdown after eating, while fasting or exercise increases fatty acid release. In people with upper-body or visceral obesity, however, this regulation is impaired, leading to persistently elevated free fatty acids that contribute to insulin resistance, high triglycerides, diabetes, and vascular dysfunction.<br /><br />A major focus of the talk was measuring adipose tissue insulin sensitivity using an IC50-based approach. Jensen reported that people with upper-body obesity show clear insulin resistance in fat depots, while lower-body obesity can remain metabolically relatively healthy. Surprisingly, his studies found that classic inflammatory markers, macrophages, and senescent cells in adipose tissue did not predict insulin resistance once fat cell size was considered. Instead, fat cell size was the strongest predictor: larger fat cells were associated with greater adipose insulin resistance.<br /><br />He concluded that the cellular mechanisms driving adipose tissue insulin resistance remain unclear, but understanding them could lead to more targeted treatments for obesity-related metabolic disease.

Keywords

adipose tissue

insulin resistance

obesity

visceral obesity

fat cell size

free fatty acids

metabolic disease

lipid metabolism

insulin sensitivity