Blood Factor Involved With Aging And Weight Loss

Certain calorie restricting dietary regimens have proven their efficacy in reducing cardiovascular disease, preventing cancer, increasing neurogenesis in the brain, and it may be possible to maintain a healthy brain in the long term. ICertain dietary restrictions such as intermittent fasting are generally acknowledged to help to improve cognitive performance and extend life in several species; restricting calorie intake by 20-30% while preserving nutritional quality has been shown to reduce the risk of CVD and cancer, while increasing production of new neurons.

Previously scientists had observed that injecting mice with blood from younger mice rejuvenated blood vessels in the brain to improve cerebral blood flow while increasing neurogenesis and cognition. The theory was put forward that since calorie restriction and supplementation with young blood were effective in regenerating organs they likely have certain mechanisms in common. 

The molecule GDF11 which belongs to the growth differentiation factor protein family and is involved in embryonic development was examined, and it is already known for its ability to rejuvenate the aged brain.  "By injecting this molecule into aged mouse models, we noticed an increase in neurogenesis and blood vessel remodeling," explains Lida Katsimpardi, a scientist in the Perception and Memory Unit and lead author of the study. Mice that were administered GDF11 lost weight without changing their appetite, which lead to the belief that GDF11 may be a link between calorie restriction and the regenerating effects of young blood. 

To confirm the theory adiponectin hormones secreted by adipose tissue which induces weight loss without affecting appetite was studied. Animals that underwent calorie restriction had high blood levels of this hormone.  "In animals that were administered GDF11, we also observed high levels of adiponectin," emphasizes Lida Katsimpardi, "and this shows that GDF11 causes metabolic changes similar to those induced by calorie restriction."

The role of GDF11 in aging and its mechanisms are not fully understood, findings of this study show that by inducing conditions similar to those for calorie restriction leading to stimulation of adiponectin and neurogenesis GDF11 contributes to creation of new neurons. "These findings are encouraging and support therapeutic uses of GDF11 in certain metabolic diseases, such as obesity, and neurodegenerative diseases," concludes Pierre-Marie Lledo, CNRS researcher, Head of the Institut Pasteur's Perception and Memory Unit and last author of the study.