Yet despite its prevalence, the cause of this depression is not understood. It's not related to how severe one's MS is, and it can occur at any stage of the disease. That suggests it is not simply a psychological reaction that comes from dealing with the burden of a serious neurologic disorder.
Now, in the first such study in living humans, researchers at UCLA suggest a cause, and it's not psychological, but physical: atrophy of a specific region of the hippocampus, a critical part of the brain involved in mood and memory, among other functions.
Reporting in the early online edition of the journal Biological Psychiatry, senior study author Dr. Nancy Sicotte, a UCLA associate professor of neurology, Stefan Gold, lead author and a postdoctoral fellow in the UCLA Multiple Sclerosis Program, and colleagues used high-resolution magnetic resonance imaging to identify three key sub-regions of the hippocampus that were found to be smaller in people with MS when compared with the brains of healthy individuals.
The researchers also found a relationship between this atrophy and hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis, a complex set of interactions among three glands. The HPA axis is part of the neuroendocrine system that controls reactions to stress and regulates many physiological processes. It's thought that this dysregulation may play a role in the atrophy of the hippocampus and the development of depression.
"Depression is one of the most common symptoms in patients with multiple sclerosis," Gold said. "It impacts cognitive function, quality of life, work performance and treatment compliance. Worst of all, it's also one of the strongest predictors of suicide."
The researchers examined three sub-regions of the hippocampus region ¯ CA1, CA3 and the dentate gyrus area of the hippocampal region called CA23DG (CA stands for cornu ammonis). They imaged 29 patients with relapsing remitting multiple sclerosis and compared them with 20 healthy control subjects who did not have MS. They also measured participants' cortisol level three times a day; cortisol is a major stress hormone produced by the HPA axis that affects many tissues in the body, including the brain.
In addition to the difference between MS patients and healthy controls, the researchers found that the multiple sclerosis patients diagnosed with depression showed a smaller CA23DG sub-region of the hippocampus, along with excessive release of cortisol from the HPA axis.
"Interestingly, this idea of a link between excessive activity of the HPA axis and reduced brain volume in the hippocampus hasn't received a lot of attention, despite the fact that the most consistently reproduced findings in psychiatric patients with depression (but without MS) include hyperactivity of the HPA axis and smaller volumes of the hippocampus," Sicotte said.
"So the next step is to compare MS patients with depression to psychiatric patients with depression to see how the disease progresses in each," she said.
Other authors of the study included Kyle C. Kern, Mary-Frances O'Connor, Michael J. Montag, Aileen Kim, Ye S. Yoo and Barbara S. Giesser, all of UCLA.
Funding was provided by the National Multiple Sclerosis Society, the National Institutes of Health, the UCLA Cousins Center for Psychoneuroimmunology, and Claire and William Vaughn.
The authors report no conflicts of interest.
The UCLA Department of Neurology encompasses more than a dozen research, clinical and teaching programs that cover brain mapping and neuroimaging, movement disorders, Alzheimer's disease, multiple sclerosis, neurogenetics, nerve and muscle disorders, epilepsy, neuro-oncology, neurotology, neuropsychology, headaches and migraines, neurorehabilitation, and neurovascular disorders. The department ranks first among its peers nationwide in National Institutes of Health funding.
For more news, visit the UCLA Newsroom and follow us on Twitter
Mark Wheeler | EurekAlert!
Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View
22.06.2018 | University of Sussex
New cellular pathway helps explain how inflammation leads to artery disease
22.06.2018 | Cedars-Sinai Medical Center
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
22.06.2018 | Materials Sciences
22.06.2018 | Earth Sciences
22.06.2018 | Life Sciences