News Briefs

Newly discovered anatomy shields and monitors brain

From the complexity of neural networks to basic biological functions and structures, the human brain only reluctantly reveals its secrets. Advances in neuro-imaging and molecular biology have only recently enabled scientists to study the living brain at a level of detail not previously achievable, unlocking many of its mysteries. The latest discovery, described in the journal Science, is a previously unknown component of brain anatomy that acts as both a protective barrier and platform from which immune cells monitor the brain for infection and inflammation.

The new study comes from the labs of Maiken Nedergaard, MD, co-director of the Center for Translational Neuromedicine at the University of Rochester and the University of Copenhagen, and Kjeld Møllgård, MD, a professor of neuroanatomy at the University of Copenhagen. “The discovery of a new anatomic structure that segregates and helps control the flow of cerebrospinal fluid (CSF) in and around the brain now provides us a much greater appreciation of the sophisticated role that CSF plays not only in transporting and removing waste from the brain but also in supporting its immune defenses,” said Nedergaard.

Central nervous system immune cells (indicated here expressing CD45) use SLYM as a platform close to the brain's surface to monitor cerebrospinal fluid for signs of infection and inflammation.

The new membrane is very thin and delicate, consisting of only a few cells in thickness. Yet Subarachnoidal LYmphatic-like Membrane, or SLYM, is a tight barrier, allowing only very small molecules to transit and it also seems to separate “clean” and “dirty” CSF. This last observation hints at the likely role played by SLYM in the glymphatic system, which requires a controlled flow and exchange of CSF, allowing the influx of fresh CSF while flushing the toxic proteins associated with Alzheimer’s and other neurological diseases from the central nervous system. This discovery will help researchers more precisely understand the mechanics of the glymphatic system, which was the subject of a recent $13 million grant from the National Institutes of Health’s BRAIN Initiative to the Center for Translational Neuromedicine at the University of Rochester.

The SLYM also appears important to the brain’s defenses. The central nervous system maintains its own native population of immune cells, and the membrane’s integrity prevents outside immune cells from entering. In addition, the membrane appears to host its own population of central nervous system immune cells that use SLYM as an observation point close to the surface of the brain from which to scan passing CSF for signs of infection or inflammation.

Newly discovered membrane in the brain called SLYM is a thin but tight barrier that appears to separate "clean" and "dirty" CSF and harbors immune cells.

Children with HIV at greater risk for impaired neurological development

Research in Zambia finds that children infected with HIV are significantly more likely to do worse in neurological assessments despite having well-controlled HIV disease, suggesting that they may struggle with cognitive and mental health issues. However, the research also indicates that early intervention—in the form of better nutrition and antiretroviral therapies—may help close the gap. The study is the most recent example of a decades-long collaboration involving an international team of researchers. Since 1994, Gretchen Birbeck, MD, a neurologist at the University of Rochester Medical Center, has partnered with the government of Zambia and clinicians and researchers with the University Teaching Hospital (UTH) in Lusaka, Zambia. Together, they study neurological problems associated with infectious diseases like HIV and malaria, which remain major public health problems in sub-Saharan Africa.

Solar panels for cells: Light-activated proton pumps generate cellular energy, extend life

New research in the journal Nature Aging takes a page from the field of renewable energy and shows that genetically engineered mitochondria can convert light energy into chemical energy that cells can use to ultimately extend the life of the roundworm C. elegans. While the prospect of sunlight-charged cells in humans is more science-fiction than science, the findings shed light on important mechanisms in the aging process.

Andrew Wojtovich, PhD, associate professor of Anesthesiology & Perioperative Medicine and Pharmacology & Physiology at the University of Rochester Medical Center, found that simply boosting metabolism using light-powered mitochondria gave laboratory worms longer, healthier lives. These findings and new research tools pave the way for researchers to further study mitochondria, identify new ways to treat age-related diseases, and find ways to support a healthier aging process.

Researchers reveal how trauma changes the brain

Exposure to trauma can be lifechanging—and researchers are learning more about how traumatic events may physically change our brains. These changes are not happening because of physical injury, rather our brain appears to rewire itself after traumatic experiences. Understanding the mechanisms involved in these changes and how the brain learns about an environment and predicts threats and safety is a focus of the ZVR Lab at the Del Monte Institute for Neuroscience at the University of Rochester, which is led by assistant professor Benjamin Suarez-Jimenez, PhD.

The findings, published in Communications Biology, identified changes in the salience network—a mechanism in the brain used for learning and survival—in people exposed to trauma (with and without psychopathologies, including PTSD, depression, and anxiety). Using fMRI, the researchers recorded activity in the brains of participants as they looked at different-sized circles—only one size was associated with a small shock (or threat). Along with the changes in the salience network, researchers found another difference— this one within the trauma-exposed resilient group. They found the brains of people exposed to trauma without psychopathologies were compensating for changes in their brain processes by engaging the executive control network— one of the dominant networks of the brain.