Results from a new study may someday lead to new treatments for memory loss, anxiety, and depression. Researchers from Columbia University Medical Center (CUMC), discovered that the skeleton exerts a powerful influence on brain development and cognitive function in unborn mice. Acting through a bone hormone, the skeleton can influence learning, memory, anxiety, and depression in adult mice. Findings in mice studies could eventually lead to new approaches to the prevention and treatment of certain neurological disorders in humans.
Normally, scientists view the brain as the organ that influences the function of other organs. The study, published in the online edition of Cell, shows the brain may be influenced by other organs, at least the bones. Earlier research showed the brain could inhibit the accumulation of bone mass but scientists often wondered if the bone could signal back to the brain to limit its negative influence and, if it did, what sort of signal it would be. This study might answer that question.
During pregnancy, the mother produces the bone hormone known as osteocalcin. This hormone crosses the placenta to promote the formation of the hippocampus, the part of the brain involved in memory learning. After birth, osteocalcin crosses the blood-brain barrier in the child and acts on various parts of the brain, including the hippocampus. There, osteocalcin causes changes in brain chemistry that prevents anxiety and depression as well as improving special learning and memory.
To determine if osteocalcin influenced the brain, researchers studied mice genetically engineered not to produce any osteocalcin. These mice had a small hippocampus and did show signs of depression and anxiety.
Gerard Karsenty, MD, Ph.D., and his team used infused these “osteocalcin-null” mice with the bone hormone to show unequivocally that osteocalcin crosses the blood-brain barrier then binds to neurons in the brainstem, midbrain, and hippocampus. Once in the brain, osteocalcin promotes the birth of neurons and increases the synthesis of several neurotransmitters, including the chemical messengers, serotonin, dopamine, and catecholamine. Changes in the production of these neurotransmitters can change the animal’s behavior.
- "Bone Hormone Influences Brain Development and Cognition." Columbia University Medical Center.
- Franck Oury, et al. "Maternal and Offspring Pools of Osteocalcin Influence Brain Development and Functions." Cell. 26 September 2013 (Vol. 155, Issue 1, pp. 228-241)