Those of you who read my blogs regularly know that I typically restrict my musings to the field of neuroscience so if you are a bit thrown by the title of this blog, bear with me… It’s tough to go a day without hearing a news story about heart disease. After all, it is the leading cause of death among US adults. Every day we are bombarded with news about what food/medication/activity/lifestyle/genes/etc can cause or prevent heart disease. There can’t be a connection between cardiovascular health and neuroscience, or can there? I certainly didn’t appreciate the connection until last week when I read about researchers at the University of Rochester Medical Center looking at the role of MLK3 (a serine/threonine kinase) in both HIV-associated dementia and heart failure (see http://www.urmc.rochester.edu/news/story/index.cfm?id=3337).

It turns out that there is also a well-documented association between heart disease and depression. The relationship appears bidirectional in that patients with heart disease are more at risk for depression and those with depression are more at risk for heart disease. While the link between these two conditions is not fully described, a number of theories exist:

1.       Behavioral – Patients with depression often smoke, eat poorly, and don’t exercise. Such behaviors are well-established risk factors for heart disease. Conversely, patients with heart disease are often overweight and diabetic, two factors linked with depression

2.       Genetic  – Abnormalities in genes such as those coding for serotonin receptors may contribute to both depression and heart disease

3.       Immunologic/Inflammatory  – Both depression and coronary heart disease have been associated with abnormalities in inflammation with increased levels of many inflammatory biomarkers

4.       Coagulation abnormalities – Depression has been linked with abnormalities in the cells lining blood vessels, which, in turn, can lead to blockages in blood vessels (ie, atherosclerosis). On the other hand, blockages in blood vessels bringing blood to the brain have been linked to depression

5.       Nutritional – Reduced levels of omega-3 polyunsaturated fatty acids may contribute to atherosclerosis and blood clot formation (contributing to heart disease) and alterations in neural function of the brain (leading to depression)

6.       Autonomic – Alterations in the activity of the autonomic nervous system (ie, the system that controls involuntary actions like the beating of our hearts and contraction/widening of our blood vessels) have been associated with the development of both depression and heart disease

The connection between neurologic/psychiatric conditions and heart disease underscores the importance of having a wide perspective when conducting research. When working on one specific aspect of one specific disease (as we tend to do in research) it can be so easy to lose sight of the fact that connecting the dots from scientific discoveries in diverse fields can have far reaching impacts. Maybe, scientific data presented at next week’s American Heart Association’s annual meeting will one day lead to treatments for depression, while data presented at next week’s Society for Neuroscience annual meeting will lead to the next heart disease treatment!