At what point did the human microbiome become such a hot topic?
When it was shown that babies born by Cesarean section are colonized with different bacteria than those born vaginally? With the cardiovascular studies of microbial byproducts of meat digestion? With the advent of fecal transplant as a proposed treatment for Clostricium difficile infection?
The bacteria and other microbes that live within the human body are thought to influence not only digestive health, but metabolic and autoimmune diseases as well, possibly even psychiatric and neurodevelopmental disorders. The field is being propelled by next-generation sequencing technology, and Nature had to publish an editorial guarding against hype (a major theme: correlation is not causation).
At Emory, investigators from several departments are involved in microbiome-related work, and the number is expanding, and assembling a comprehensive list is becoming more difficult. Researchers interested in the topic are planning Emory’s first microbiome symposium in November, organized by Jennifer Mulle (read her intriguing review on autism spectrum disorders and the microbiome).
Microbial genomics expert Tim Read, infectious diseases specialist Colleen Kraft and intestinal pathologist Andrew Neish have formed an Emory microbiome interest group with a listserv and seminars. Read more
From Emory Medicine, Spring 2013
A small clinical study of clarithromycin for the sleep disorder hypersomnia shows that the antibiotic can combat patients’ subjective experience of sleepiness, but it does not seem to improve reaction time measured in a video-game-type vigilance task.
The effects of clarithromycin in hypersomnia were first observed by Emory doctors when an early patient (Anna Sumner, whose story is told in this Emory Medicine article) unexpectedly experienced sleeplessness when taking it for a respiratory infection.
The results of the study were published online by Annals of Neurology on June 10.
Lynn Marie Trotti, MD, David Rye, MD, PhD and colleagues from the Department of Neurology and Emory Sleep Center conducted the study, which involved 23 patients.
Advantages of clarithromycin:
- It’s inexpensive and widely available.
- It’s an option for people dealing with hypersomnia for whom other medications, such as modafinil, are not helpful or tolerable.
- It represents an alternative to flumazenil, the benzodiazepine antidote that has been shown to help some hypersomnia patients. Flumazenil used to be very scarce, and shortages occur (Hypersomnia Foundation/American Society of Health System Pharmacists).
Disadvantages of clarithromycin:
- It’s an antibiotic, so it probably changes intestinal bacteria.
- Chronic use could promote the growth of antibiotic-resistant bacteria.
- Most patients reported an altered sense of taste or smell. Some describe this as a metallic mouth sensation.
Part of the new Winship magazine feature on prostate cancer focuses on a PET imaging probe called FACBC, which was developed by radiologists at Emory. 18F-FACBC (anti-1-amino-3-[18F]fluorocyclobutane-1-carboxylic acid, also called “fluciclovine”) has a lengthening track record in detecting recurrent prostate cancer.
Structure of FACBC, from patent application.
Usually in PET imaging, radioactive glucose is injected into the body, and since cancer cells have a sweet tooth, they take up a lot of the radioactive tracer. But plenty of the tracer also appears in the urine, complicating prostate cancer detection efforts, since the prostate is so close to the bladder. In contrast, FACBC is readily taken up by prostate cancer cells, but doesn’t appear as much in urine.
Because of space considerations, we did not include David Schuster’s description of how FACBC’s utility in prostate was first discovered. Several years ago, he and Mark Goodman had begun investigating the probe’s potential in imaging brain tumors and kidney tumors, and used it with a patient with a large renal mass and many enlarged lymph nodes, as described in the radiology newsletter Aunt Minnie. Read more
Neuroscientists at Emory have refined a map showing which parts of the brain are activated during head rotation, resolving a decades-old puzzle. Their findings may help in the study of movement disorders affecting the head and neck, such as cervical dystonia and head tremor.
The results were published in Journal of Neuroscience.
In landmark experiments published in the 1940s and 50s, Canadian neurosurgeon Wilder Penfield and colleagues determined which parts of the motor cortex controlled the movements of which parts of the body.
Penfield stimulated the brain with electricity in patients undergoing epilepsy surgery, and used the results to draw a “motor homunculus”: a distorted representation of the human body within the brain. Penfield assigned control of the neck muscles to a region between those that control the fingers and face, a finding inconsistent with some studies that came later.
Using modern functional MRI (magnetic resonance imaging), researchers at Emory University School of Medicine have shown that the neck’s motor control region in the brain is actually between the shoulders and trunk, a location that more closely matches the arrangement of the body itself.
“We can’t be that hard on Penfield, because the number of cases where he was able to study head movement was quite limited, and studying head motion as he did, by applying an electrode directly to the brain, creates some challenges,” says lead author Buz Jinnah, MD, professor of neurology, human genetics and pediatrics at Emory University School of Medicine. Read more
If you’ve come anywhere near Alzheimer’s research, you’ve come across the “amyloid hypothesis” or “amyloid cascade hypothesis.”
This is the proposal that deposition of amyloid-beta, a major protein ingredient of the plaques that accumulate in the brains of Alzheimer’s patients, is a central event in the pathology of the disease. Lots of supporting evidence exists, but several therapies that target beta-amyloid, such as antibodies, have failed in large clinical trials.
Lary Walker and Matthias Jucker in Tübingen, 2014
In a recent Nature News article, Boer Deng highlights an emerging idea in the Alzheimer’s field that may partly explain why: not all forms of aggregated amyloid-beta are the same. Moreover, some “strains” of amyloid-beta may resemble spooky prions in their ability to spread within the brain, even if they can’t infect other people (important!).
Prions are the “infectious proteins” behind diseases such as bovine spongiform encephalopathy. They fold into a particular structure, aggregate and then propagate by attracting more proteins into that structure.
Lary Walker at Yerkes National Primate Research Center has been a key proponent of this provocative idea as it applies to Alzheimer’s. To conduct key experiments supporting the prion-like properties of amyloid-beta, Walker has been collaborating with Matthias Jucker in Tübingen, Germany and spent four months there on a sabbatical last year. Their paper, describing how aggregated amyloid-beta is “seeded” and spreads through the brain in mice, was recently published in Brain Pathology.
Severe sepsis, a consequence of the body’s response to infection, is a major cause of death in hospitals. The earlier that doctors recognize that a patient has sepsis, the earlier the patient can be treated with antibiotics, fluids and other measures, and the better the chance of survival.
That’s why critical care and emergency medicine researchers have been looking for ways to spot whether someone coming to the hospital might have sepsis, even before arrival.
At Emory, Carmen Polito, Jonathan Sevransky and colleagues recently published a paper in the American Journal of Emergency Medicine on an emergency medical services screening tool for severe sepsis. Polito and Sevransky are in the division of pulmonary, allergy, critical care and sleep medicine in the Department of Medicine. The tool was evaluated based on Grady emergency medical services data from 2011 and 2012.
“Sepsis is largely a face without a name in the EMS setting, “ Polito says. “The goal of our study was to create a tool to assist EMS providers in naming this deadly condition at the point of first medical contact. Similar to other life-threatening, time-sensitive conditions like stroke and heart attack, naming sepsis is the first step in developing coordinated care pathways that focus on delivering rapid, life-saving treatment once the patient arrives at the hospital.”
At the American Diabetes Association meeting in Boston on Sunday, cardiology researcher Salim Hayek presented evidence that the biomarker suPAR (soluble urokinase-type plasminogen activator receptor) can help in predicting the risk of developing chronic kidney disease.
Hayek and colleagues at Emory Clinical Cardiovascular Research Institute showed that levels of suPAR could partially predict a patient’s rate of decline in glomerular filtration rate, a measure of kidney function, over the following decade.
Nephrologists estimate that more than 20 million Americans have chronic kidney disease and millions of others are at risk of developing it. Chronic kidney disease contributes to the risk of cardiovascular disease events such as heart attack and stroke. Treatment of CKD usually involves addressing underlying problems of diabetes and high blood pressure.
There are limitations on the two indicators that doctors usually use to check whether someone’s kidneys are in trouble: serum creatinine (used to estimate glomerular filtration rate) and protein in the urine.
The data Hayek presented comes from the ECCRI’s studies of close to 2300 patients undergoing cardiac catheterization at Emory. People with suPAR levels in the third and fourth quartiles had a two- or three-fold increased risk of developing CKD over the next decade, compared to those in the lowest quartile.
“Measurement of plasma suPAR level may be a practical and cost-effective tool for identification of adults at higher risk of developing CKD early in the course of disease,” the researchers conclude. Read more
Posted on June 8, 2015
The big news from the recent American Society of Clinical Oncology meeting has been largely about immunotherapy drugs, also known as checkpoint inhibitors. These drugs have been shown to be effective in prolonging life in patients with some types of cancer, such as lung cancer and melanoma, but not others, such as colorectal and prostate cancer.
Lab Land asked oncologist Bradley Carthon and immunology researcher Haydn Kissick why. Both Carthon’s clinical work and Kissick’s lab research on prostate cancer are featured in the new issue of Winship magazine, but the prostate feature just touches on checkpoint inhibitors briefly.
Carthon says the reason checkpoint inhibitors haven’t moved the needle with prostate cancer is “likely due to the absence of infiltration of the prostatic tissue by tumor-associated lymphocytes.”
Checkpoint inhibitors are supposed to unleash the immune system, but if the immune cells aren’t in contact with the cancer cells so that the drugs can spur them into action, they won’t help much. Carthon says: “The answer may be to ‘prime’ the prostate with an agent, then introduce the checkpoint inhibitors.” Read more
Virologists at Emory, Yerkes and Children’s Healthcare of Atlanta have uncovered a critical detail explaining how HIV assembles its infectious yet stealthy clothing.
Paul Spearman, MD
For HIV to spread from cell to cell, the viral envelope protein needs to become incorporated into viral particles as they emerge from an infected cell. Researchers led by Paul Spearman have found that a small section of the envelope protein, located on its “tail”, is necessary for the protein to be sorted into viral particles.
The results were published June 1 in Proceedings of the National Academy of Sciences. Read more
The third winner of the Best Image contest from the Postdoctoral Research Symposium, from postdoc Joshua Strauss in electron microscopist Elizabeth Wright’s lab.
Tetherin is a host cell factor that mechanically links HIV-1 to the plasma membrane. This is the first time anyone has imaged tethered HIV-1 by cryo-electron tomography. In doing so, we were able to learn about the length and arrangement of the tethers.
Note: Tetherin also studied by Paul Spearman + colleagues.
Cryo-electron tomography is an imaging technique which enables scientists to look at biological specimens in a “native-like” (frozen hydrated) state, without the chemical fixatives or heavy metal stains typically used for conventional electron microscopy.
The 3D reconstruction was manually segmented to highlight the different viral and cellular components: HIV-1 virions (lavender), mature conical-cores (aqua blue), immature Gag lattice (pink), plasma membrane (peach), rod-like tethers (sea green).