Thursday, May 3, 2018
Findings may help expand window for storing organs before transplantation, therapeutic hypothermia
Researchers at the National Eye Institute have discovered cellular mechanisms that help the 13-lined ground squirrel survive hibernation. Their findings could be a step to extending storage of human donor tissues awaiting transplantation and protecting traumatic brain injury patients who undergo induced hypothermia. NEI is part of the National Institutes of Health. The findings were published in the May 3 issue of Cell.
During hibernation, the 13-lined ground squirrel endures near freezing temperatures, dramatically slowing its heart rate and respiration. How the squirrel’s tissues adapt to the cold and metabolic stress has confounded researchers.
A structure in cells known to be vulnerable to cold is the microtubule cytoskeleton. This network of small tubes within a cell provides structural support and acts as a kind of inner cellular railway system, transporting organelles and molecular complexes vital for a cell’s survival.
In a series of experiments, the research team led by Wei Li, Ph.D., a senior investigator in the NEI Retinal Neurophysiology Section and Jingxing Ou, Ph.D., a postdoctoral scientist in Li’s lab, compared cells from non-hibernators to cells from the ground squirrel to determine differences in their response to cold. They found that in ground squirrel neurons the microtubule cytoskeleton remains intact while it deteriorates in the neurons of humans and other non-hibernating animals, including rats.
“By understanding the biology of cold adaptation in hibernation, we may be able to improve and broaden the applications of induced hypothermia in the future, and perhaps prolong the viability of organs prior to transplantation,” Li said. “Kidneys, for example, are typically stored for no more than 30 hours. After that, the tissue starts to deteriorate, impairing the organ’s ability to function properly after its been rewarmed and reperfused. Heart, lungs and livers have an even shorter shelf life.”
Monday, April 16, 2018
NIH study finds higher rates of dissatisfaction with family relationships
Cyberbullying, dissatisfaction with family relationships, and unmet medical needs are major contributors to the high rates of depressive symptoms seen among adolescents who are gay, lesbian, bisexual or questioning their sexual orientation, according to researchers at the National Institutes of Health. Their new study on sexual minority youth now appears in Pediatrics.
Researchers used data from the NEXT Generation Health Study, a study from 2009-2016 of 2,785 high school students in 22 states, to assess teens’ depressive symptoms beginning at age 17 and continuing for three years after they left high school. They found that almost 30 percent of sexual minority teens thought they did not have adequate medical care for a 12-month period prior to the study, compared to 19 percent for heterosexual teens. Teens questioning their sexual orientation or attracted to the same sex or both sexes may fear that providers would disclose information to parents or may be embarrassed to seek mental health services, the authors wrote.
“The study shows that adolescence is a critical window for interventions to address depressive symptoms experienced by sexual minority youth,” said Jeremy Luk, Ph.D., first author of the study and postdoctoral researcher at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development. “Without appropriate screening and intervention, these disparities may likely persist into young adulthood.”
Monday, April 16, 2018
IRP scientists report single dose elicited long-term protection
Two genetically modified broadly neutralizing antibodies (bNAbs) protected rhesus macaques from an HIV-like virus, report scientists at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. After introducing genetic mutations into two potent HIV bNAbs, researchers prepared intravenous infusions of two bNAbs known as 3BNC117-LS and 10-1074-LS. Single infusions of each modified bNAb protected two groups of six monkeys each against weekly exposures to simian-human immunodeficiency virus (SHIV) for up to 37 weeks, compared with a median of three weeks in 12 monkeys receiving no antibody. SHIV is a manmade virus commonly used in HIV nonhuman primate studies.
The study, led by Malcolm A. Martin, M.D., chief of the NIAID Laboratory of Molecular Microbiology, also assessed the efficacy of injecting a combination of both modified bNAbs into six monkeys subcutaneously — a route of administration considered more feasible in resource-limited clinical settings. This bNAb mixture, administered at a three-fold lower concentration than the individual antibodies infused intravenously, protected this group of monkeys for a median of 20 weeks.
This human T cell (blue) is under attack by HIV (yellow), the virus that causes AIDS. The virus specifically targets T cells, which play a critical role in the body's immune response against invaders like bacteria and viruses.
Monday, April 16, 2018
Study provides insights into the immune system’s role in recovery after concussion in mice
Following head injury, the protective lining that surrounds the brain may get a little help from its friends: immune cells that spring into action to assist with repairs. In a new study, scientists from the National Institutes of Health watched in real-time as different immune cells took on carefully timed jobs to fix the damaged lining of the brain, also known as meninges, in mice. These results may help provide clues to the discovery that the meninges in humans may heal following mild traumatic brain injury (mTBI) and why additional hits to the head can be so devastating.
“The lining of the brain, with help from the immune system, has a remarkable ability to put itself back together again after injury,” said Dorian McGavern, Ph.D., scientist at the NIH’s National Institute of Neurological Disorders and Stroke and the senior author of the study published in Nature Immunology. “As we learn more about all the cells involved in the repair process, we may be able to identify potential targets for therapy that lead to better outcomes for patients.”
The study came about from an observation on MRI scans of adult patients who experienced a concussion or mTBI. Around half of patients with mTBI show evidence of injury to blood vessels in the meninges, which appears on MRI scans as a vascular dye leaking out of the damaged vessels.
One day after head injury (left), bright dye along the edge of the brain suggests damage to the meninges, or the brain’s protective lining. After 35 days (right), the dye no longer appears, indicating the meninges may have healed.
Friday, April 13, 2018
Preliminary IRP study shows increased levels of beta-amyloid
Losing just one night of sleep led to an immediate increase in beta-amyloid, a protein in the brain associated with Alzheimer’s disease, according to a small, new study by researchers at the National Institutes of Health. In Alzheimer’s disease, beta-amyloid proteins clump together to form amyloid plaques, a hallmark of the disease.
While acute sleep deprivation is known to elevate brain beta-amyloid levels in mice, less is known about the impact of sleep deprivation on beta-amyloid accumulation in the human brain. The study is among the first to demonstrate that sleep may play an important role in human beta-amyloid clearance.
“This research provides new insight about the potentially harmful effects of a lack of sleep on the brain and has implications for better characterizing the pathology of Alzheimer's disease,” said George F. Koob, Ph.D., director of the National Institute on Alcohol Abuse and Alcoholism (NIAAA), part of the National Institutes of Health, which funded the study.
Beta-amyloid is a metabolic waste product present in the fluid between brain cells. In Alzheimer’s disease, beta-amyloid clumps together to form amyloid plaques, negatively impacting communication between neurons.
Led by Drs. Ehsan Shokri-Kojori and Nora D. Volkow of the NIAAA Laboratory of Neuroimaging, the study is now online in the Proceedings of the National Academy of Sciences. Dr. Volkow is also the director of the National Institute on Drug Abuse at NIH.
Brain imaging after one night of sleep deprivation revealed beta-amyloid accumulation in the hippocampus and thalamus, regions affected by Alzheimer’s disease.
Wednesday, April 11, 2018
Study finds gene mutations that cause “dripping candle wax” bone disease
Researchers at the National Institutes of Health worked with 15 patients from around the world to uncover a genetic basis of “dripping candle wax” bone disease. The rare disorder, known as melorheostosis, causes excess bone formation that resembles dripping candle wax on x-rays. The results, appearing in Nature Communications, offer potential treatment targets for this rare disease, provide important clues about bone development, and may lead to insights about fracture healing and osteoporosis.
Though there are only about 400 known cases of this disorder worldwide, 15 unrelated adults with the condition from around the globe volunteered to come to the NIH Clinical Center to undergo biopsies of both affected and unaffected bones. The condition causes pain and bone deformity, which can limit the function of bones.
“Scientists previously assumed that the genetic mutations responsible for melorheostosis occurred in all cells of a person with the disorder,” said co-senior author Timothy Bhattacharyya, M.D., head of the Clinical and Investigative Orthopaedics Surgery Unit at the National Institute on Arthritis and Musculoskeletal and Skin Diseases (NIAMS) at NIH. “Our team hypothesized that mutations might only occur in the affected bone tissue.”
An x-ray image of a patient with melorheostosis shows excess bone formation, likened to dripping candle wax.
Wednesday, April 11, 2018
In a new study, researchers identified genetic subtypes of diffuse large B-cell lymphoma (DLBCL) that could help explain why some patients with the disease respond to treatment and others don’t. The study, led by researchers in the Center for Cancer Research (CCR) at the National Cancer Institute (NCI), part of the National Institutes of Health, with additional authors from several institutions around the world, was published online April 11, 2018, in The New England Journal of Medicine.
DLBCL is the most common type of lymphoma. Although it can be aggressive, it is potentially curable, and in some patients treatment eliminates the disease. However, researchers still don’t have a full understanding of why some lymphomas of this type respond to treatment and others don’t. The standard treatment for the disease is a combination of chemotherapy drugs plus rituximab, a drug known as a monoclonal antibody.
Several years ago, researchers defined two major subgroups of DLBCL that arise from different cells of origin and that have different patterns of gene activity. They found that patients with activated B-cell-like (ABC) DLBCL have about a 40 percent average survival rate, while those with germinal center B-cell-like (GCB) DLBCL have about a 75 percent average survival rate. But even in the GCB subgroup, many patients experience disease relapse after treatment.
“The first question we wanted to tackle was whether there were other molecular features of the tumors that could help us explain why some people were well-served by chemotherapy,” explained Louis M. Staudt, M.D., Ph.D., of NCI’s CCR, who led the new study. “And the second, related question was, if we could understand who was not responding well to treatment, could we understand the genetics of these tumors to suggest new potential therapies beyond chemotherapy? The answer to both questions was ‘yes.’”
Subgroups of DLBCL by gene expression (left) defined several years ago. Genetic subtypes identified in the new study (right) that each share a group of genetic aberrations. Curved connectors indicate relationships between the subgroups and subtypes.
Monday, April 9, 2018
Crimean-Congo hemorrhagic fever (CCHF) is a viral disease spread by ticks in the Middle East, Asia, Africa and parts of Europe. Infection with CCHF virus is fatal in nearly one of every three cases. No specific treatments or vaccines for CCHF exist, primarily because a suitable animal model for studying the disease has not been available. Scientists have used mice to study CCHF but had to weaken their immune systems to cause infection. Studies in larger animals have not consistently replicated human disease.
Now, as reported in Nature Microbiology, researchers have developed a new animal model to study the disease. Scientists at the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, conducted a pilot study using CCHF virus to infect African green monkeys, rhesus macaques, and cynomolgus macaques. The strain of the virus they used, known as Kosova Hoti, was isolated from the blood of a person who died of CCHF. Most prior animal modeling studies had used a different viral strain isolated from a tick found in Nigeria.
The first two monkey species showed no signs of disease using various inoculation methods. Two of three cynomolgus macaques, however, developed disease. That led to a larger study of 12 cynomolgus macaques, four each inoculated under the skin, intravenously, or a combination of both. Within three days, all eight animals in the combination and intravenous groups showed signs of infection that led to severe disease. Two of the four animals inoculated under the skin developed mild signs of disease while the other two remained symptom-free.
Scanning electron micrograph of CCHF viral particles (yellow) budding from the surface of cultured epithelial cells from a patient.
Thursday, April 5, 2018
Results could advance treatments for head and neck and other cancers
Researchers supported by the National Institutes of Health have uncovered molecular characteristics that link the genomic profiles of squamous cell carcinomas (SCCs) from five areas of the body and that set these SCCs apart from other cancers. Using a robust dataset of SCCs from the head and neck, lung, esophagus, cervix, and bladder, the researchers also found defining characteristics in subtypes of SCCs associated with tobacco use or human papillomavirus (HPV) infection. This research may lead to more effective diagnosis and treatment of these cancers by helping researchers develop tailored strategies for specific cancer subtypes.
Published in Cell Reports, the study was led by Carter Van Waes, M.D., Ph.D., and his colleague Zhong Chen, M.D., Ph.D., from the Head and Neck Surgery Branch of NIH’s National Institute on Deafness and Other Communication Disorders (NIDCD). They collaborated with teams of researchers across the United States and Canada through The Cancer Genome Atlas (TCGA) consortium, a joint effort of the NIH’s National Cancer Institute (NCI) and National Human Genome Research Institute (NHGRI).
The study is one of 27 papers published in Cell journals this month, that describe important results from the PanCancer Atlas, a detailed analysis from a dataset containing molecular and clinical information on more than 10,000 tumors from 33 forms of cancer. The PanCancer Atlas is a culmination of more than a decade of work by more than 150 TCGA researchers at institutions across North America.
Monday, April 2, 2018
NIH researchers suggest lifestyle changes may reduce hypertension risk
Elevated blood pressure before conception may increase the chances for pregnancy loss, according to an analysis by researchers at the National Institutes of Health. The authors conclude that lifestyle changes to keep blood pressure under control could potentially reduce the risk of loss. The study appears in Hypertension.
The analysis found that for every 10 mmHg increase in diastolic blood pressure (pressure when the heart is resting between beats), there was an 18-percent-higher risk for pregnancy loss among the study population. Millimeter of mercury, or mmHg, is the unit of measure used for blood pressure. The researchers also found a 17 percent increase in pregnancy loss for every 10 mmHg increase in mean arterial pressure, a measure of the average pressure in the arteries during full heart beat cycles. The study was conducted by researchers at the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD).
“Elevated blood pressure is linked to heart disease, stroke, and kidney disease” said the study’s senior author, Enrique Schisterman, Ph.D., chief of the Epidemiology Branch at NICHD. “Our findings suggest that attaining a healthy blood pressure before pregnancy could not only have benefits later in life, but also reduce the chances for pregnancy loss.”