- The map of the human body has just been radically changed.
- Scientists discovered new vessels that connect the brain to the immune system.
- Could have effects on study and treatment of neurological diseases ranging from autism to Alzheimer's.
- Scientist: We always perceived it before as something esoteric that can't be studied. But now we can ask physical questions.
- See also related medical articles published in before this discovery that found a connection between thoughts and the immune system performance. They just did not know how it happened.
- And how spending quiet time in a natural setting, such as taking a walk in the park or in a real forest, can boost your immune system. Your positive thoughts in a beautiful setting can affect your body and your health.
Illustration: Maps of the immune system. Left, the old map. Right, the new map with recent discovery of brain-to-immune system vessels.
Credit: University of Virginia Health System
In a stunning discovery that overturns decades of textbook teaching, researchers at the University of Virginia School of Medicine have determined that the brain is directly connected to the immune system by vessels previously thought not to exist.
That such vessels could have escaped detection when the lymphatic system has been so thoroughly mapped throughout the body is surprising on its own, but the true significance of the discovery lies in the effects it could have on the study and treatment of neurological diseases ranging from autism to Alzheimer's disease to multiple sclerosis.
More information: Structural and functional features of central nervous system lymphatic vessels, DOI: 10.1038/nature14432
It begins to suggest a mechanism for why subjects with a more positive emotional disposition may be healthier," he says. Janice Kiecolt-Glaser, an expert on stress and immunity at Ohio State University, told the New York Times that the study represents "some of the best evidence we've seen to date."
Jonathan Kipnis, PhD, professor in the UVA Department of Neuroscience and director of UVA's Center for Brain Immunology and Glia (BIG) said:
Photo U of Virginia
"Instead of asking, 'How do we study the immune response of the brain?' 'Why do multiple sclerosis patients have the immune attacks?' now we can approach this mechanistically.
"Because the brain is like every other tissue connected to the peripheral immune system through meningeal lymphatic vessels".
"It changes entirely the way we perceive the neuro-immune interaction. We always perceived it before as something esoteric that can't be studied. But now we can ask mechanistic questions."
"We believe that for every neurological disease that has an immune component to it, these vessels may play a major role," Kipnis said. "Hard to imagine that these vessels would not be involved in a [neurological] disease with an immune component."
The unexpected presence of the lymphatic vessels raises a tremendous number of questions that now need answers, both about the workings of the brain and the diseases that plague it.
For example, take Alzheimer’s disease. “In Alzheimer’s, there are accumulations of big protein chunks in the brain,” Kipnis said. “We think they may be accumulating in the brain because they’re not being efficiently removed by these vessels.”
He noted that the vessels look different with age, so the role they play in aging is another avenue to explore.
New Discovery in Human Body
Kevin Lee, PhD, chairman of the UVA Department of Neuroscience, described his reaction to the discovery by Kipnis' lab: "The first time these guys showed me the basic result, I just said one sentence: 'They'll have to change the textbooks.'
"There has never been a lymphatic system for the central nervous system, and it was very clear from that first singular observation - and they've done many studies since then to bolster the finding - that it will fundamentally change the way people look at the central nervous system's relationship with the immune system."
Even Kipnis was skeptical initially. "I really did not believe there are structures in the body that we are not aware of. I thought the body was mapped," he said. "I thought that these discoveries ended somewhere around the middle of the last century. But apparently they have not."
'Very Well Hidden'
|Antoine Louveau |
Photo U of Virginia
The discovery was made possible by the work of Antoine Louveau, PhD, a postdoctoral fellow in Kipnis' lab.
The vessels were detected after Louveau developed a method to mount a mouse's meninges - the membranes covering the brain - on a single slide so that they could be examined as a whole.
"It was fairly easy, actually," he said. "There was one trick: We fixed the meninges within the skullcap, so that the tissue is secured in its physiological condition, and then we dissected it. If we had done it the other way around, it wouldn't have worked."
2003: Brain study links negative emotions
and lowered immunity
Brain activity linking negative emotions to a lower immune response against disease has been revealed for the first time, claim researchers.
Many previous studies have shown that emotions and stress can adversely affect the immune system. But this effect had not been directly correlated with activity in the brain, says study leader Richard Davidson, at the University of Wisconsin, Madison, in the US.
The part of the brain the team studied, the prefrontal cortex (PFC), is associated with depression. People who had the greatest activity in the right PFC when asked to dwell on distressing episodes in their life had a markedly lower antibody levels after an influenza vaccination. In contrast, those showing exceptional activity in the left PFC when recalling happy times developed high antibody levels.
Davidson says emotions play an important role in regulating systems in the body that influence health. "This study establishes that people with a pattern of brain activity that has been associated with positive [emotions] are also the ones to show the best response to the flu vaccine."
However, the study could not explain exactly how having a positive attitude boosts the immune system. (Now we know)
2010: Optimism boosts the immune system
Optimism doesn't just boost your mood. According to new research, a glass-half-full attitude also strengthens the immune system.
The study, which tracked changes in optimism and immune response among first-year law students, found that as students became more optimistic, they showed stronger cell-mediated immunity, the flood of immune cells that respond to an invasion by foreign viruses or bacteria. When optimism dropped, so did cell-mediated immunity.
Previous studies have established the connection between the psychological and the physical.
Everything from marital spats to job stress can delay healing and promote disease.
But previous research on optimism and the immune system has mostly compared optimists with pessimists, leaving open the possibility that other factors, like genetics and personality, could affect immune function.
"To show that a single person — with the same personality and genes — has different immune function when he or she feels more or less optimistic provides a stronger link between the two," said study co-author and University of Kentucky psychology professor Suzanne Segerstrom.
To investigate the connection, Segerstrom recruited 124 incoming law students and had them complete five questionnaires and immunity checks over the course of a year. The questionnaires measured students' optimism by asking how closely they identified with statements like "I will be less successful than most of my classmates."
To test immunity, the students had a dose of dead mumps virus or candida yeast injected under the skin of the forearm. These harmless cocktails trigger a cellular immune response, resulting in a small bump at the injection site. By measuring the bump, researchers can estimate the strength of the immune response.
As the students experienced classes, exams and internship interviews, their optimism levels rose and fell. So did their cell-mediated immunity. When optimism went up, so did the cell-mediated immune response. When optimism dropped, the immune system weakened.
The results also suggested that optimism affects immunity in part by increasing positive emotions, Segerstrom said. The next step, she said, is to look for similar effects in older people whose immune systems might already be vulnerable to infection.
The results could have implications for how mental health professionals approach counseling and treatment, said Margaret Kemeny, a health psychologist at UC San Francisco who was not involved in the research.
Many psychological treatments focus on reducing negative emotions and stress, Kemeny said, but Segerstrom's research suggests that bolstering the positive could be fruitful as well.
"It may not be optimum to only focus on the negative," Kemeny said.
How visiting a forest - or your nearby park - can boost your immune system
Most of us sense that taking a walk in a forest is good for us. We take a break from the rush of our daily lives.
We enjoy the beauty and peace of being in a natural setting.
Now research is showing that visiting a forest has real, quantifiable health benefits, both mental and physical.
Even five minutes around trees or in green spaces may improve health. Think of it as a prescription with no negative side effects that's also free.
What a forest can do for you, according to scientific studies:
- Boosts immune system
- Lowers blood pressure
- Reduces stress
- Improves mood
- Increases ability to focus, even in children with ADHD
- Accelerates recovery from surgery or illness
- Increases energy level
- Improves sleep