Warren symposium follows legacy of geneticist giant

If we want to understand how the brain creates memories, and how genetic disorders distort the brain’s machinery, then the fragile X gene is an ideal place to start. That’s why the Stephen T. Warren Memorial Symposium, taking place November 28-29 at Emory, will be a significant event for those interested in neuroscience and genetics. Stephen T. Warren, 1953-2021 Warren, the founding chair of Emory’s Department of Human Genetics, led an international team that discovered Read more

Mutations in V-ATPase proton pump implicated in epilepsy syndrome

Why and how disrupting V-ATPase function leads to epilepsy, researchers are just starting to figure Read more

Tracing the start of COVID-19 in GA

At a time when COVID-19 appears to be receding in much of Georgia, it’s worth revisiting the start of the pandemic in early 2020. Emory virologist Anne Piantadosi and colleagues have a paper in Viral Evolution on the earliest SARS-CoV-2 genetic sequences detected in Georgia. Analyzing relationships between those virus sequences and samples from other states and countries can give us an idea about where the first COVID-19 infections in Georgia came from. We can draw Read more
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microbiome

FMT microbial transplant for C diff gaining acceptance

In February, the Infectious Diseases Society of America issued new guidelines for fighting Clostridium difficile, the hardy bacterium that can cause life-threatening diarrhea and whose dominance is sometimes a consequence of antibiotic treatment. The guidelines recommend for the first time that FMT (fecal microbiota transplant) be considered for individuals who have repeatedly failed standard antibiotics.

In a nice coincidence, Emory FMT specialists Colleen Kraft and Tanvi Dhere recently published a look at their clinical outcomes with C diff going back to 2012, in Clinical Infectious Diseases. They report 95 percent of patients (122/128) indicated they would undergo FMT again and 70 percent of the 122 said they would prefer FMT to antibiotics as initial treatment if they were to have a recurrence. Read more

Posted on February 23, 2018 by Quinn Eastman in Immunology Leave a comment

Leaky gut plus diet together drive liver disease

 

Frank Anania, MD

Lots of people in the United States consume a diet that is high in sugar and fat, and many develop non-alcoholic fatty liver disease, a relatively innocuous condition. NASH (non-alcoholic steatohepatitis) is the more unruly version, linked to elevated risk of cardiovascular and metabolic diseases, and can progress to cirrhosis. NASH is expected to become the leading indication for liver transplant. But only a fraction of people with non-alcoholic fatty liver disease go on to develop NASH.

Thus, many researchers are trying to solve this equation:

High-sugar, high-fat diet plus X results in NASH.

Emory hepatologist Frank Anania and colleagues make the case in a recent Gastroenterology paper that a “leaky gut”, allowing intestinal microbes to promote liver inflammation, could be a missing X factor.

Anania’s lab started off with mice fed a diet high in saturated fat, fructose and cholesterol (in the figure, PrintHFCD). This combination gives the mice moderate fatty liver disease and metabolic syndrome (see this 2015 paper, and we can expect to hear more about this model soon from Saul Karpen). Leaky gut, brought about by removing a junction protein from intestinal cells, sped up and intensified the development of NASH.

The authors say that this model could be useful for the study of NASH, which has been difficult to reproduce in mice.

The researchers could attenuate liver disease in the mice by treatment with antibiotics or sevelamer, a phosphate binding polymer that soaks up inflammatory toxins from bacteria. Sevelamer is now used to treat excess phosphate in patients with chronic kidney disease, and is being studied clinically in connection with insulin resistance.
Read more

Posted on August 29, 2016 by Quinn Eastman in Uncategorized Leave a comment

Measuring microbiome disruption

How should doctors measure how messed up someone’s intestinal microbiome is?

This is the topic of a recent paper in American Journal of Infection Control from Colleen Kraft and colleagues from Emory and the Centers for Disease Control and Prevention. The corresponding author is epidemiologist Alison Laufer Halpin at the CDC.

A “microbiome disruption index” could inform decisions on antibiotic stewardship, where a patient should be treated or interventions such as fecal microbial transplant (link to 2014 Emory Medicine article) or oral probiotic capsules.

What the authors are moving towards is similar to Shannon’s index, which ecologists use to measure diversity of species. Another way to think about it is like the Gini coefficient, a measure of economic inequality in a country. If there are many kinds of bacteria living in someone’s body, the disruption index should be low. If there is just one dominant type of bacteria, the disruption index should be high.

In the paper, the authors examined samples from eight patients in a long-term acute care hospital (Wesley Woods) who had recently developed diarrhea. Using DNA sequencing, they determined what types of bacteria were present in patients’ stool. The patients’ samples were compared with those from two fecal microbial transplant donors. Read more

Posted on March 21, 2016 by Quinn Eastman in Immunology, Uncategorized Leave a comment

An effective alternative to fecal transplant for C. difficile?

Bacterial spores in capsules taken by mouth can prevent recurrent C. difficile infection, results from a preliminary study suggest.

Clostridium difficile is the most common hospital-acquired infection in the United States and can cause persistent, sometimes life-threatening diarrhea. Fecal microbiota transplant has shown promise in many clinical studies as a treatment for C. difficile, but uncertainty has surrounded how such transplants should be regulated and standardized. Also, the still-investigational procedure is often performed by colonoscopy, which may be difficult for some patients to tolerate.

The capsule study, published Monday in Journal of Infectious Diseases, represents an important step in moving away from fecal microbiota transplant as a treatment for C. difficile, says Colleen Kraft, MD, assistant professor of pathology and laboratory medicine and medicine (infectious diseases) at Emory University School of Medicine.

Kraft and Tanvi Dhere, MD, assistant professor of medicine (digestive diseases) have led development of the fecal microbiota transplant program at Emory. They are authors on the capsule study, along with investigators from Mayo Clinic, Massachusetts General Hospital, Miriam Hospital (Rhode Island), and Seres Therapeutics, the study sponsor.

While this study involving 30 patients did not include a control group, the reported effectiveness of 96.7 percent compares favorably to published results on antibiotic treatment of C. difficile infection or fecal microbial transplant. Read more

Posted on February 12, 2016 by Quinn Eastman in Uncategorized Leave a comment

Wound-healing intestinal bacteria: like shrubs after a forest fire

In injured mouse intestines, specific types of bacteria step forward to promote healing, Emory scientists have found. One oxygen-shy type of bacteria that grows in the wound-healing environment, Akkermansia muciniphila, has already attracted attention for its relative scarcity in both animal and human obesity.

NMicro

An intestinal wound brings bacteria (red) into contact with epithelial cells (green). The bacteria can provide signals that promote healing, if they are the right kind.

The findings emphasize how the intestinal microbiome changes locally in response to injury and even helps repair breaches. The researchers suggest that some of these microbes could be exploited as treatments for conditions such as inflammatory bowel disease.

The results were published on January 27 in Nature Microbiology. Researchers took samples of DNA from the colon tissue of mice after they underwent colon biopsies. They used DNA sequencing to determine what types of bacteria were present.

“This is a situation resembling recovery after a forest fire,” says Andrew Neish, MD, professor of pathology and laboratory medicine at Emory University School of Medicine. “Once the trees are gone, there is an orderly succession of grasses and shrubs, before the reconstitution of the mature forest. Similarly, in the damaged gut, we see that certain kinds of bacteria bloom, contribute to wound healing, and then later dissipate as the wound repairs.” Read more

Posted on February 9, 2016 by Quinn Eastman in Immunology, Uncategorized Leave a comment

Metagenomics explainer

A term we heard a bunch at the Emory Microbiome Symposium in November was “metagenomics”. Time for an explainer, with some help from Emory geneticist Tim Read.

Nature Reviews Microbiology defines metagenomics as “genomic analysis of microbial DNA that is extracted directly from communities in environmental samples.”

This technology — genomics on a huge scale — enables a survey of the different microorganisms present in a specific environment, such as water or soil, to be carried out. Metagenomics is also emerging as a tool for clinical diagnosis of infectious diseases.

Read notes that the term specifically refers to “shotgun” sequencing of environmental DNA.

“The shotgun approach is to randomly sample small pieces of the DNA in the tube, no matter which organism they came from,” he says. “The output is a mélange of different genes from bacteria, viruses, fungi, plants and humans.  The data is fascinating but the analysis is daunting.” Read more

Posted on December 15, 2015 by Quinn Eastman in Uncategorized 1 Comment

Providing the potent part of probiotics

A Emory News item on a helpful part of the microbiome focuses on how the same type of bacteria – lactobacilli – activates the same ancient signaling pathway in intestinal cells in both insects and mammals. It continues a line of research from Rheinallt Jones and Andrew Neish on how beneficial bacteria stimulate wound healing by activating ROS (reactive oxygen species).

Asma Nusrat, MD

A idea behind this research is: if we know what parts of the bacteria stimulate healing, perhaps doctors can deliver that material, or something very close, to patients directly to treat intestinal diseases such as Crohn’s or ulcerative colitis.

This idea has advanced experimentally, as demonstrated by two papers from Jones and Neish’s frequent collaborator, Asma Nusrat, who recently moved from Emory to the University of Michigan. This team had shown that a protein produced by human intestinal cells called annexin A1 activates ROS, acting through the same N-formyl peptide receptors that bacteria do.

Nusrat told me Friday her team began investigating annexins a decade ago at Emory, and it was fortuitous that Neish was working on beneficial bacteria right down the hall, since it is now apparent that annexin A1 and the bacteria are activating the same molecular signals. (Did you know there is an entire conference devoted to annexins? I didn’t until a few days ago.)

In a second Journal of Clinical Investigation paper published this February, Nusrat and her colleagues show that intestinal cells release vesicles containing annexin A1 following injury. The wound closure-promoting effects of these vesicles can be mimicked with nanoparticles containing annexin A1. The nanoparticles incorporate a form of collagen, which targets them to injured intestinal tissue. Read more

Posted on August 18, 2015 by Quinn Eastman in Immunology, Uncategorized Leave a comment

Microbiome enthusiasm at Emory

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.

Microbiome symposium sponsors: ACTSI, Hercules Exposome Center, Emory University School of Medicine, Omega Biotek, CFDE, Ubiome. Read more

Posted on June 30, 2015 by Quinn Eastman in Immunology, Neuro Leave a comment

A crystal ball for Lab Land: Top 5 topics in 2015

Alzheimer’s protein pathology

While a wise Dane once proposed that predictions are dangerous, especially concerning the future, it’s usually helpful to plan ahead. Here are five biomedical research topics we think will occupy our attention in 2015.

1. Alzheimer’s We’re hearing discordant music coming from Alzheimer’s researchers. Large pharmaceutical companies are shutting down clinical trials in frustration, but researchers keep coming forward with biomarkers that might predict future disease. This confusing situation calls for some new thinking. Allan Levey, Jim Lah and colleagues have been preparing the way for a “beyond the usual suspects” look at Alzheimer’s disease. We are looking forward to Levey’s appearance at the 2015 AAAS meeting and to drug discovery wizard Keqiang Ye’s continuing work on new therapeutic targets.

2. Ebola While the scare over Ebola in the United States may be over (we hope so!), the outbreak continues to devastate countries in West Africa. Clinical trials testing vaccines and experimental drugs are underway or will be soon. Read more

Posted on January 2, 2015 by Quinn Eastman in Uncategorized Leave a comment
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