Tuesday, March 13, 2018
Promising concept may lead to an alternative to antibiotics
Researchers are developing a promising alternative to antibiotic treatment for infections caused by Klebsiella pneumoniae bacteria resistant to carbapenem antibiotics. The approach uses antibodies to target the K. pneumoniae protective capsule polysaccharide, allowing immune system cells called neutrophils to attack and kill the bacteria. The early stage, in vitro research was conducted by scientists at the National Institute of Allergy and Infectious Diseases’ (NIAID) Rocky Mountain Laboratories and the New Jersey Medical School-Rutgers University.
Klebsiella bacteria cause about 10 percent of all hospital-acquired infections in the United States. A carbapenem-resistant K. pneumoniae strain known as multilocus sequence type 258 (ST258) is one of the antibiotic-resistant organisms labeled an urgent threat by the Centers for Disease Control and Prevention. ST258 is particularly concerning because it is resistant to most antibiotics. It is a significant cause of mortality among people with bloodstream infections.
Tuesday, March 13, 2018
Study of flies suggests neurodegenerative disorders may speed up aging process
To understand the link between aging and neurodegenerative disorders such as Alzheimer’s disease, scientists from the National Institutes of Health compared the genetic clocks that tick during the lives of normal and mutant flies. They found that altering the activity of a gene called Cdk5 appeared to make the clocks run faster than normal, and the flies older than their chronological age. This caused the flies to have problems walking or flying later in life, to show signs of neurodegeneration, and to die earlier.
“We tried to untangle the large role aging appears to play in some of the most devastating neurological disorders,” said Edward Giniger, Ph.D., senior investigator at the NIH’s National Institute of Neurological Disorders and Stroke and the senior author of the study published in Disease Models & Mechanisms. “Our results suggest that neurodegenerative disorders may accelerate the aging process.”
On average, the normal flies in this study lived for 47 days. To create a genetic clock, Dr. Giniger’s team measured the levels of every gene encoded in messenger RNA molecules from cells from the heads and bodies of flies at 3, 10, 30, and 45 days after birth. This allowed the researchers to use advanced analysis techniques to search for the genes that seemed to be sensitive to aging, and create a standard curve, or timeline, that described the way they changed.
Thursday, March 8, 2018
Monoclonal antibodies (mAbs) — preparations of a specific type of antibody designed to bind to a single target — have shown promise in the fight against cancer and autoimmune diseases. They also may play a critical role in future battles against emerging infectious disease outbreaks, according to a new article by scientists from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. The article is published online this week by the New England Journal of Medicine and outlines the potential uses for mAbs as treatments for infectious diseases and as a prevention tool for protecting individuals at risk of infection and slowing disease outbreaks.
The article, written by NIAID Director Anthony S. Fauci, M.D., and colleagues Hilary D. Marston, M.D., M.P.H., and Catharine I. Paules, M.D., highlights the research advances that could allow for rapid, strategic deployment of mAbs to prevent and treat emerging infectious diseases and, potentially, alter the course of epidemics.
Ebola virus particles (red) on a larger cell. ZMAPP, a potential treatment for Ebola, includes a cocktail of monoclonal antibodies.
Thursday, March 8, 2018
Familial human prion diseases are passed within families and are associated with 34 known prion protein mutations. To determine whether three of the unstudied mutations are transmissible, scientists from the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, exposed research mice to brain samples from three people who died from a familial prion disease. After observing the mice for about two years, they found two of the mutations, Y226X and G131V, are transmissible.
Perhaps more interesting, the Y226X patient sample had previously been preserved in formaldehyde for three days, embedded in wax, and dried on glass specimen slides for several years before being rehydrated for the study. Yet, the sample infected four of eight mice.
The finding illustrates the hardiness of prion infectivity and the potential risks associated with prion transmission, potentially through surgery, blood transfusion or tissue donation. Samples for the other two mutations studied were taken from frozen brain tissue that was thawed.
Thursday, March 1, 2018
Researchers can predict variants’ impact, recall participants to test predictions
Databases such as the 1000 Genomes Project and the Exome Aggregation Consortium (ExAC) harbor large numbers of genotypes (an individual’s collection of genes). Until now, it has been difficult for researchers to re-contact individuals with genotypes of interest and investigate the health consequences of their genes and gene variants. To address this challenge, National Institutes of Health and Inova Health System researchers are launching The Genomic Ascertainment Cohort (TGAC), a two-year pilot project that will allow them to recall genotyped people and examine the genes and gene variants’ influence on their phenotypes, an individual’s observable traits, such as height, eye color or blood type.
The project reverses a long-standing research paradigm of examining a person’s traits or symptoms and then searching for genes or gene variants that cause or contribute to them. NIH will establish a new database of 10,000 human genomes and exomes, the 1-2 percent of the genome that contains protein-coding genes. Once the database is established, NIH and Inova researchers will predict conditions that specific genes or gene variants might produce and test those predictions by re-examining individuals who donated their DNA sequence information to the database. TGAC will be based in the Washington, D.C., area and only people who’ve expressly given consent to be re-contacted will participate in TGAC.
“We’re trying to advance science in a new, creative and slightly radical way,” said Leslie Biesecker, M.D., TGAC co-organizer and chief of the Medical Genomics and Metabolic Genetics Branch at NIH’s National Human Genome Research Institute (NHGRI). “Our goal is to determine what genes and gene variants do. We’re especially interested in using this as a platform to test our ability to predict phenotype from genotype – one of the key underpinnings of predictive genomic medicine.” NHGRI will host the database and administer the program.
Monday, February 26, 2018
Study in mice suggests that experimental drug may be effective against mountain sickness and other polycythemias
Researchers at the National Institutes of Health have cured mice with Chuvash polycythemia, a life-threatening disorder that involves the overproduction of red blood cells. They treated the mice using Tempol, an experimental drug being studied for treatment of diabetes, cancer and other diseases. The findings offer hope that Tempol or a similar drug may treat polycythemias that affect humans, such as mountain sickness—a serious blood complication experienced in low-oxygen, high-altitude settings. The study appears in The Journal of Clinical Investigation.
Chuvash polycythemia is a rare, inherited disorder that is endemic to the Chuvash Republic of Russia, though it does occur in other parts of the world. NIH studies rare diseases not only to help the people who have them, but also to gain insight into gene functions that may benefit people with more common conditions. Complications of Chuvash polycythemia include blood clots and cerebral hemorrhage. The condition results from a genetic mutation that makes people unable to break down hypoxia inducible factor 2α (HIF2α), a protein that helps stimulate red blood cell production. The inability to degrade HIF2α leads to higher red cell production, even under high-oxygen conditions.
Friday, February 23, 2018
Natural history investigation will deploy latest advances to identify biomarkers, targets for early therapy
A new clinical study led by the National Eye Institute (NEI), part of the National Institutes of Health, will follow 500 people over five years to learn more about the natural history of early age-related macular degeneration (AMD). By using the latest technologies to visualize structures within the eye and measure their function, researchers hope to identify biomarkers of disease progression, well before it advances to late-stage disease and causes vision loss. AMD is the leading cause of vision impairment and blindness among people age 50 and older in the United States.
“The findings will contribute to our understanding of the underlying biology driving the transition from early to late-stage disease so that therapies can be developed to halt its progression,” said the study’s lead investigator, Emily Y. Chew, M.D., deputy clinical director at NEI and director of the NEI Division of Epidemiology and Clinical Applications. “Treatments that halt the disease at its early stage would have an enormous public health impact.”
Fundus photo shows giraffe-like macular pattern in the retina of a person with reticular pseudodrusen.
Friday, February 9, 2018
National Institutes of Health scientists developing a rapid, practical test for the early diagnosis of prion diseases have modified the assay to offer the possibility of improving early diagnosis of Parkinson’s disease and dementia with Lewy bodies. The group, led by NIH’s National Institute of Allergy and Infectious Diseases (NIAID), tested 60 cerebral spinal fluid samples, including 12 from people with Parkinson’s disease, 17 from people with dementia with Lewy bodies, and 31 controls, including 16 of whom had Alzheimer’s disease. The test correctly excluded all the 31 controls and diagnosed both Parkinson’s disease and dementia with Lewy bodies with 93 percent accuracy.
Importantly, test results were available within two days, compared to related assays that require up to 13 days. The group conducted the tests using Real-Time Quaking-Induced Conversion (RT-QuIC), an assay developed and refined over the past decade at NIAID’s Rocky Mountain Laboratories. Scientists from the University of California San Diego, University of Verona in Italy, Indiana University School of Medicine, Indianapolis, and the Case Western Reserve University School of Medicine, Cleveland, collaborated on the project. The research findings were published in Acta Neuropathologica Communications.
NIAID’s Bradley Groveman, foreground, and Christina Orru using the RT-QuIC diagnostic assay, which they helped adapt to detect Parkinson’s disease and dementia with Lewy bodies.
Thursday, February 8, 2018
Ebola virus can infect the reproductive organs of male and female macaques, according to a study published in The American Journal of Pathology, suggesting that humans could be similarly infected. Prior studies of survivors of the 2014-2016 Ebola outbreak in West Africa have revealed sexual transmission of Ebola virus, and that viral RNA (Ebola virus genetic material) can persist in semen following recovery. While little is known about viral persistence in female reproductive tissues, pregnant women with Ebola virus disease have a maternal death rate of more than 80 percent and a fetal death rate of nearly 100 percent.
In this study, investigators from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, and from Thomas Jefferson University infected four female and eight male macaques with the Makona variant of Ebola virus, the variant responsible for the recent West Africa outbreak. All the macaques succumbed to Ebola virus disease and were euthanized six to nine days after infection. The scientists then took reproductive tissue samples from each macaque and analyzed the samples for signs of Ebola virus infection, organ and tissue damage, and immune responses. They found widespread Ebola virus infection of reproductive organs with minimal tissue immune response or signs of disease.
Colorized transmission electron micrograph of the ovary from a nonhuman primate infected with Ebola virus. Characteristic filamentous Ebola virus particles are present between cells (bright red). Intracytoplasmic Ebola virus inclusion bodies forming crystalline arrays can be seen within ovarian stromal cells (darker red).
Wednesday, February 7, 2018
Preliminary results suggest strokes also affect the eye
Research into curious bright spots in the eyes on stroke patients’ brain images could one day alter the way these individuals are assessed and treated. A team of scientists at the National Institutes of Health found that a chemical routinely given to stroke patients undergoing brain scans can leak into their eyes, highlighting those areas and potentially providing insight into their strokes. The study was published in Neurology.
“We were kind of astounded by this – it’s a very unrecognized phenomenon,” said Richard Leigh, M.D., an assistant clinical investigator at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and the paper’s senior author. “It raises the question of whether there is something we can observe in the eye that would help clinicians evaluate the severity of a stroke and guide us on how best to help patients.”
Eyes yield information about strokes: MRI scans revealed that a chemical called gadolinium, used to improve images, leaked into the eyes of stroke patients.