Immunological Memory in Weight Cycling
Caslin’s research suggests that while weight loss is good for metabolic health, the immune cells in fat tissue appear to “remember” former weight gain. The immune cell populations that infiltrate into the fat, expand with, and activate upon weight gain are retained following weight loss. These cells are known to contribute to insulin resistance and the development of diabetes.
Moreover, Dr. Caslin showed that adipose macrophages specifically develop innate immune memory, or trained innate immunity, which primes them for enhanced activation to bacterial stimuli like LPS or to regain weight. Cycles of weight gain and loss increase risk for diseases like diabetes and hypertension when compared to stable weight gain, and thus, adipose macrophage memory may play a causal role in weight cycling- accelerated disease risk.
Weight cycling is very common, as weight loss is hard to do and hard to maintain. Thus, Caslin’s research helps us to understand one mechanism by which weight cycling may worsen disease risk. Moreover, it suggests that adipose macrophage memory may be a potential therapeutic target in weight cycling- accelerated diabetes.