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

Reddit as window into opioid withdrawal strategies

Drug abuse researchers are using the social media site Reddit as a window into the experiences of people living with opioid addiction. Abeed Sarker in Emory's Department of Biomedical Informatics has a paper in Clinical Toxicology focusing on the phenomenon of “precipitated withdrawal,” in collaboration with emergency medicine specialists from Penn, Rutgers and Mt Sinai. Precipitated withdrawal is a more intense form of withdrawal that can occur when someone who was using opioids starts medication-assisted treatment Read more

CROI: HIV cure report and ongoing research

The big news out of CROI (Conference on Retroviruses and Opportunistic Infections) was a report of a third person being cured of HIV infection, this time using umbilical cord blood for a hematopoetic stem cell transplant. Emory’s Carlos del Rio gave a nice overview of the achievement for NPR this morning. As del Rio explains, the field of HIV cure research took off over the last decade after Timothy Brown, known as “the Berlin patient,” Read more

Eliver Ghosn

Detecting vulnerable plaque with a laser-induced whisper

A relatively new imaging technique called photoacoustic imaging or PAI detects sounds produced when laser light interacts with human tissues. Working with colleagues at Michigan State, Emory immunologist Eliver Ghosn’s lab is taking the technique to the next step to visualize immune cells within atherosclerotic plaques.

The goal is to more accurately spot vulnerable plaque, or the problem areas lurking within arteries that lead to clots, and in turn heart attacks and strokes. A description of the technology was recently published in Advanced Functional Materials

“I believe we are now closer to developing a more precise method to diagnose and treat life-threatening atherosclerotic plaques,” Ghosn says. “Our method could be deployed in combination with IVUS to significantly improve its accuracy and sensitivity, or it could be used non-invasively.”

From science fiction movies, we might think lasers come with a “pow” sound. Photoacoustic imaging is more like listening for a whisper: sounds associated with heat generated by a laser pulse when it is absorbed by tissue.

Earlier this year, the FDA approved a photoacoustic imaging system for detection of breast cancer. Several companies are developing photoacoustic imaging systems, and what we might call “plain vanilla” PAI is currently being tested on carotid artery plaque in clinical studies in Europe.

Ghosn’s approach, developed with biomedical engineer Bryan Smith at Michigan State, adds specificity by adding nanoparticle probes taken up by macrophages, the immune cells that accumulate within atherosclerotic plaques. The nanoparticles, administered before imaging, act as contrast agents.

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Neutrophils flood lungs in severe COVID-19

“First responder” cells called neutrophils are the dominant type of immune cells flooding the airways of people with severe COVID-19, according to a recent analysis of African-American patients in Emory hospitals.

The findings were posted on the preprint server Biorxiv prior to peer review.

Neutrophils are the most abundant immune cells in the blood, and usually the first to arrive at the site of a bacterial or viral infection. But in the lungs of severe COVID-19 patients, neutrophils camp out and release tissue-damaging enzymes, the new research shows. They also produce inflammatory messengers that induce more neutrophils to come to the lungs. 

Lung inflammation photo from NIEHS. Most of these dense small cells are neutrophils

This circulating cell type enters the lung and initiates a self-sustaining hyper-inflammation that leads to acute respiratory distress syndrome (ARDS), the leading cause of mortality in COVID-19, says lead author Eliver Ghosn assistant professor of medicine at Emory University School of Medicine.

“Our findings reveal novel therapeutic targets, and developing tactics to intervene could benefit severe patients in the ICU, particularly those that are most vulnerable,” Ghosn says. “We compared our lung data with matching blood samples for all the patients, and we were able to identify the subtype of neutrophils in the blood that is most likely to infiltrate the lungs of severe patients and cause ARDS.”

Somewhat counter-intuitively, Emory researchers had difficulty detecting SARS-CoV-2 infected cells in the upper airways of hospitalized patients. This result, consistent with findings by others, may explain why antiviral drugs such as remdesivir are ineffective once systemic inflammation has gained momentum; lung injury comes more from the influx of immune cells, such as neutrophils, rather than viral infection itself.

When Ghosn and his colleagues began examining immune cells in COVID-19, they found that almost all of the hospitalized patients they encountered were African-American. This highlights the racial disparities of the COVID-19 pandemic, especially in Georgia, and Ghosn’s team decided to “lean in” and focus on African-Americans. They collaborated closely with Eun-Hyung Lee’s lab at Emory to collect samples from hospitalized patients. 

“We believe these results can have broader implications and be applied to other demographics that suffer from similar lung pathology,” Ghosn says.

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