Culture

New research has shown that COVID-19 infections in healthcare workers during the first wave of the pandemic provided an accurate sample of the general population, suggesting that data from healthcare workers could be used to estimate the severity of future viruses more quickly.

The study, led by researchers from RCSI University of Medicine and Health Sciences in collaboration with IBM Research, is published in PLOS ONE.

The researchers analysed the infection data from healthcare workers and the progression of the first wave of the COVID-19 outbreak using the reported daily infection numbers in Ireland. Using similar data in four other countries (Germany, UK, South Korea and Iceland), computer models showed how the disease progressed in different countries related to their approach to testing, tracing and lockdown restrictions.

Healthcare workers in Ireland made up 31.6% of all test-confirmed infections while only representing 3% of the population. However, the researchers found that the healthcare worker data closely related to that of the entire population after using software to create a more accurate picture of how widespread the disease was.

This suggests that governments could use data from only healthcare workers to inform decisions on whether to implement restrictions, wide-scale testing and contact tracing for future viruses.

"As we have seen with the COVID-19 pandemic, implementing countermeasures early can save lives and reduce the spread of the disease," said RCSI Professor of Chemistry Donal O'Shea, who led the work.

"However, wide-scale testing can take time to set up, delaying decisions and costing lives. While the healthcare population is no longer an accurate sample of the general population for COVID-19 due to different vaccination rates, governments could use data from their healthcare worker population to make informed decisions on what measures to implement earlier when future viruses emerge."

The research noted that very few nations were able to set up effective systems that tested the entire population, carried out contact tracing and quarantined those infected with COVID-19.

"Setting up wide-scale testing systems for healthcare workers is much easier than setting up a similar programme for everyone since the infrastructure for testing for diseases is always in place in healthcare settings," said Dr Dan Wu, honorary lecturer in the RCSI Department of Chemistry and first author on the paper.

"A screening programme that tested all healthcare workers would have the additional benefit of catching asymptomatic spread of the disease since all healthcare workers would be tested. If governments could catch highly infectious diseases and implement countermeasures early, this could possibly prevent new viruses from erupting into another epidemic/pandemic."

Scientists have revealed how an antibiotic of 'last resort' kills bacteria.

The findings, from Imperial College London and the University of Texas, may also reveal a potential way to make the antibiotic more powerful.

The antibiotic colistin has become a last resort treatment for infections caused by some of the world's nastiest superbugs. However, despite being discovered over 70 years ago, the process by which this antibiotic kills bacteria has, until now, been something of a mystery.

Now, researchers have revealed that colistin punches holes in bacteria, causing them to pop like balloons. The work, funded by the Medical Research Council and Wellcome Trust, and published in the journal eLife, also identified a way of making the antibiotic more effective at killing bacteria.

Colistin was first described in 1947, and is one of the very few antibiotics that is active against many of the most deadly superbugs, including E. coli, which causes potentially lethal infections of the bloodstream, and Pseudomonas aeruginosa and Acinetobacter baumannii, which frequently infect the lungs of people receiving mechanical ventilation in intensive care units.

These superbugs have two 'skins', called membranes. Colistin punctures both membranes, killing the bacteria. However, whilst it was known that colistin damaged the outer membrane by targeting a chemical called lipopolysaccharide (LPS), it was unclear how the inner membrane was pierced.

Now, a team led by Dr Andrew Edwards from Imperial's Department of Infectious Disease, has shown that colistin also targets LPS in the inner membrane, even though there's very little of it present.

Dr Edwards said: "It sounds obvious that colistin would damage both membranes in the same way, but it was always assumed colistin damaged the two membranes in different ways. There's so little LPS in the inner membrane that it just didn't seem possible, and we were very sceptical at first. However, by changing the amount of LPS in the inner membrane in the laboratory, and also by chemically modifying it, we were able to show that colistin really does puncture both bacterial skins in the same way - and that this kills the superbug. "

Next, the team decided to see if they could use this new information to find ways of making colistin more effective at killing bacteria.

They focussed on a bacterium called Pseudomonas aeruginosa, which also causes serious lung infections in people with cystic fibrosis. They found that a new experimental antibiotic, called murepavadin, caused a build up of LPS in the bacterium's inner skin, making it much easier for colistin to puncture it and kill the bacteria.

The team say that as murepavadin is an experimental antibiotic, it can't be used routinely in patients yet, but clinical trials are due to begin shortly. If these trials are successful, it may be possible to combine murepavadin with colistin to make a potent treatment for a vast range of bacterial infections.

Akshay Sabnis, lead author of the work also from the Department of Infectious Disease, said: "As the global crisis of antibiotic resistance continues to accelerate, colistin is becoming more and more important as the very last option to save the lives of patients infected with superbugs. By revealing how this old antibiotic works, we could come up with new ways to make it kill bacteria even more effectively, boosting our arsenal of weapons against the world's superbugs."

University of South Australia researchers have identified an enzyme that may help to curb chronic kidney disease, which affects approximately 700 million people worldwide.

This enzyme, NEDD4-2, is critical for kidney health, says UniSA Centre for Cancer Biology scientist Dr Jantina Manning in a new paper published this month in Cell Death & Disease.

The early career researcher and her colleagues, including 2020 SA Scientist of the Year Professor Sharad Kumar, have shown in an animal study the correlation between a high salt diet, low levels of NEDD4-2 and advanced kidney disease.

While a high salt diet can exacerbate some forms of kidney disease, until now, researchers did not realise that NEDD4-2 plays a role in promoting this salt-induced kidney damage.

"We now know that both a high sodium diet and low NEDD4-2 levels promote renal disease progression, even in the absence of high blood pressure, which normally goes hand in hand with increased sodium," says Dr Manning.

NEDD4-2 regulates the pathway required for sodium reabsorption in the kidneys to ensure correct levels of salt are maintained. If the NEDD4-2 protein is reduced or inhibited, increased salt absorption can result in kidney damage.

Even people on a low salt diet can get kidney damage if they have low levels of NEDD4-2 due to genetic variations or mutations in the gene.

Prof Kumar says the long-term goal is to develop a drug that can increase NEDD4-2 levels in people with chronic kidney disease (CKD).

"We are now testing different strategies to make sure this protein is maintained at a normal level all the time for overall kidney health," Prof Kumar says.

"In diabetic nephropathy - a common cause of kidney disease - levels of NEDD4-2 are severely reduced. This is the case even when salt is not a factor."

The study also revealed a surprising finding: that the high salt diet induced kidney disease is not always due to high blood pressure.

"In a lot of cases, kidney disease is exacerbated by hypertension, so we wanted to investigate that link in our study. In fact, we found the complete opposite - that a high salt diet caused excessive water loss and low blood pressure. This is significant because it means that kidney disease can also happen in people who don't have high blood pressure," Dr Manning says.

A 2020 Lancet paper estimated that about 700 million people - or 10 per cent of the world's population - suffer from chronic kidney disease, which represents a 29 per cent increase in the past 30 years.

The huge spike in CKD is mainly attributed to a global obesity epidemic in recent decades, leading to diabetes, one of the leading causes of chronic kidney disease along with high blood pressure.

World Health Organization statistics reveal a 300 per cent increase in diabetes between 1980 and 2014, making it one of the top 10 causes of death worldwide and showing the gravity of the problem facing scientists trying to tackle kidney disease.

"Obesity and lifestyle are two main factors driving chronic kidney disease but there are other things at play as well," says Dr Manning. "Acute kidney injuries, drugs taken for other conditions, high blood pressure and a genetic predisposition can also cause it."

Pioneering neural recordings in patients with Parkinson's disease by UC San Francisco scientists lays the groundwork for personalized brain stimulation to treat Parkinson's and other neurological disorders.

In a study published May 3rd in Nature Biotechnology, UCSF Weill Institute for Neurosciences researchers implanted novel neurostimulation devices that monitor brain activity for many months, with and without deep brain stimulation (DBS) therapy. Pairing the brain recordings with wearable monitors of movement, they identified patterns of brain activity corresponding to specific movement abnormalities associated with Parkinson's. Their research provides the first evidence, during normal activities of daily living, for a long-held hypothesis that Parkinson's symptoms are related to erratic brain wave patterns, and demonstrate how DBS restores order to patient brain waves.

"We can record hundreds of hours of brain wave activity wirelessly as patients go about normal activities," said Philip Starr, MD, PhD, the Dolores Cakebread Professor of Neurological Surgery at UCSF and senior author of the study. "It allows us, really for the first time, to understand the brain activity behind specific neurological problems as they occur in the real world."

Parkinson's disease is a degenerative neurological disorder that causes slow movement (bradykinesia), trouble walking, and tremors, as well as symptoms unrelated to movement. According to the Parkinson's Foundation, some 60,000 Americans are diagnosed with Parkinson's disease every year. The exact cause of Parkinson's is not known, but all patients show decreased levels of dopamine - a neurotransmitter that regulates motivation in the brain.

It's long been suspected that erratic brain wave patterns also play a role in triggering Parkinson's symptoms. Previous research in monitoring brain wave activity of Parkinson's patients has been limited to short periods in clinical settings. This greatly limits the amount of data available for analysis - providing a limited glimpse of patient brain activity which cycles and changes throughout the day.

Starr and study lead author Ro'ee Gilron, PhD, a postdoctoral scholar in the Department of Neurological Surgery, sought to get a more complete picture. They implanted small sensors that measure electrical activity into the subthalamus and motor cortex brain areas of five patients with Parkinson's disease. These sensors were connected to pulse generators enabled to sense brain activity. This allowed for continuous recording of brain activity while patients went about their daily routine.

Months of recordings produced a massive amount of data. To sort through it all, the researchers developed an algorithm to compare brain wave activity with data recorded from movement-sensing devices that patients wore on their wrists. They discovered that periods of dyskinesia (excessive movement induced by medications) and bradykinesia corresponded with exaggerated brain waves in specific frequency bands, both in the subthalamus and in motor cortex.

After months of recording and analysis, the researchers went further and measured the effect of DBS on the patients. DBS delivers electrical impulses into the brain and has long been used to ameliorate the symptoms of Parkinson's disease, though why it worked was not previously understood. This study demonstrated that deep brain stimulation appears to improve Parkinson's symptoms by regulating patients' erratic brain wave patterns, partly by suppressing lower frequency waves that inhibit movement, and regulating higher frequency waves that promote movement.

Previous studies using implanted recording systems could not record the effects of active stimulation on brain wave activity because the electrical signals created by stimulation caused recording interference. In the new study, Gilron and colleagues developed a workaround using the same principal used in noise cancelling headphones. By offsetting the electrical waves created by stimulation, the researchers could make the signals cancel each other out, allowing for accurate recording of brain waves by the recording lead.

"This is the first time we've been able to measure the effect of continuous stimulation on brain waves," said Gilron. "We've done deep brain stimulation in hundreds of thousands of patients before without any way to monitor the immediate effect. It was like trying to treat blood pressure without measuring it."

These broad findings help clarify some underlying factors in Parkinson's Disease, but every Parkinson's patient will likely have their own unique brain wave fluctuations. The researchers say that this is exactly why continuous neural recording is so crucial to successful treatment. The massive dataset accumulated from patient recordings helps to reveal the most minute brain wave patterns that correlate with Parkinson's symptoms. With proper analysis, onset of Parkinson's symptoms could be anticipated, and brain wave patterns corrected when symptoms manifest.

"It's like the Hubble Space Telescope," said Gilron. "We could view the night sky before it, but Hubble allowed us to see much greater detail and volume and it led to unique discoveries. I hope that this technique will as well."

The next step for the researchers is a randomized clinical trial including 10 patients. The researchers believe that this will greatly accelerate individualized treatments for Parkinson's disease because new algorithms to identify symptom patterns can be tested immediately, as opposed to the years and sometimes decades involved in developing new medications.

The findings also have potential beyond Parkinson's disease, the researchers say. Numerous neurological disorders related to erratic brain wave activity like epilepsy, chronic depression and chronic pain could likely be treated in the same way -- through real-time monitoring of brain activity and personalized neuromodulation.

"We're looking at the Parkinson's population as a way to develop this platform," said Starr. "Hopefully this will be utilized in disorders where we currently don't have any effective stimulation therapies."

Blood may seem like a simple fluid, but its chemistry is complex. When too much potassium, for instance, accumulates in the bloodstream, patients may experience deadly irregular heart rhythms.

Cardiovascular scientists at Virginia Tech's Fralin Biomedical Research Institute at VTC are studying why.

In a new study, published in Pflügers Archiv European Journal of Physiology, the research team led by Steven Poelzing, associate professor at the institute, describes how subtle changes in potassium, calcium, and sodium levels regulate heartbeats.

Poelzing says that the results could help researchers and physicians understand the nuances of cardiac arrythmias, as well as a group of genetic disorders that impact sodium channel function, such as Brugada syndrome.

The scientists elevated blood potassium in guinea pigs, creating a condition called hyperkalemia, which causes some of the heart's key electrical conduits, sodium channels, to shut down. Next, they increased calcium levels and observed the heart muscle cells pressing closer together. This miniscule motion - spanning mere nanometers - helps preserve electrical conduction in the heart.

"We know the heart is extremely sensitive to changes in blood electrolyte levels, but until recently we didn't have a great picture of how the heart's molecular landscape is remodeled, and how these muscle cells adapt," said Poelzing, who is also an associate professor in the Virginia Tech College of Engineering's department of biomedical engineering and mechanics.

Heart muscle cells primarily pass electrical signals via a network of protein bridges called gap junctions and sodium channels. These pathways let nutrients and positively charged minerals flow between cells. When there are too many positively charged potassium ions in the blood, however, the cells get overstimulated and temporarily block signaling channels.

"This can be dangerous when sodium channels get stuck in a half-closed state. The cell isn't dying, but it's not as electrically active as it once was. This can cause dangerous heart arrythmias and sudden cardiac death," Poelzing said.

When the heart's core electrical pathways falter, heart muscle cells press closer together, allowing them to sense subtle electric fields generated by neighboring cells. This secondary form of cell-to-cell signaling is known as ephaptic coupling.

"Ephaptic coupling appears to address the effects of a functional loss of sodium channels, in this case caused by high potassium, and helps keep the current flowing properly across the heart muscle," Poelzing said.

Over the course of the eight-year study, Poelzing's team tested different concentrations of sodium and calcium to treat the electrical defects associated with high potassium to see how the heart would respond. They discovered that increasing sodium and calcium levels together greatly reduced the distances between cells, providing a substantial improvement in cardiac conduction.

In the clinic, human patients with hyperkalemia who develop abnormal heart rhythms are administered intravenous calcium gluconate. Poelzing's findings help explain why elevating calcium levels under these certain clinical conditions is beneficial.

"What surprised me is that such small changes in electrolyte values have such dramatic effects," said Ryan King, the study's first author and a postdoctoral research associate in the lab of Scott Johnstone, an assistant professor at the Fralin Biomedical Research Institute. "The ranges of sodium, calcium, and potassium we used in this study are not exaggerated, extreme ionic conditions that you'd never find in a clinical setting. They're all within ranges that could show up in metabolic blood panels."

Boston, MA (May 2, 2021) - A new study, presented today at the AATS 101st Annual Meeting, finds that AATS Foundation fellowships support success in academic surgery career tracks. The AATS Foundation has two primary grant funding mechanisms: the AATS Foundation Scholarship and the Surgical Investigator Award. The study looked at publications, citations, NIH funding, and leadership position of awardees, among other factors.

Results show that recipients of both the AATS Surgical Investigator award and the Foundation Scholarship demonstrate sustained scholarship with peer reviewed publications and a high rate of receiving one or more NIH grants. The AATS grants place individuals on a career path for academic surgery with impressive scholastic contributions and ascending to leadership positions.

The AATS Foundation Grant has been awarded to 42 individuals. Awardees have a median of 4,733 citations. During the four-year window following the award, awardees published a median of 23 manuscripts, with a median of 364 citations. Subsequent NIH grant funding was attained by 44 percent of awardees, who al; secured 2-3 additional NIH grants. The majority of awardees - 89 percent - have been promoted, with most holding either a clinical directorship or a division chief position.

The Surgical Investigator award has been awarded to 24 surgeons. In the four-year window since the grant was awarded, recipients generated a media of 37 publications with a media of 632 citations. 26 percent secured NIH funding, of which all attained second and third NIH grants. Half of the awardees obtained an academic promotion.

"There's a narrative within academic medicine that surgery is too time consuming to allow for research, and the data here shows that there are real opportunities for surgical researchers that yield results," said Edgar Aranga-Michel, MD/PhD candidate at University of Pittsburgh - CMU. "The AATS fellowships are a success factor that support a career in academic surgery.

Boston, MA (May 2, 2021) - A new study, presented today at the AATS 101st Annual Meeting, found that heart transplantation using donation after cardiac death (DCD) with normothermic regional perfusion (NRP) is feasible in the United States. Broader application of DCD heart transplantation has the potential to increase cardiac allograft availability by 20-30 percent. Over a one-year period, from January 2020 to January 2021, eight heart transplants were performed using cardiopulmonary bypass (CPB) for immediate regional reperfusion and cardiac unloading to accomplish optimal myocardial salvage. All hearts were successfully resuscitated and weaned from CPB with no inotropic support and all were accepted for transplantation. Post-transplant cardiac function was excellent in all recipients.

Improving the number and quality of organs available for transplantation is a key objective that improves outcomes for patients. The DCD process has been used with success in the United Kingdom, Belgium and Australia. This study is the first to measure outcomes in the United States.

"Our study addresses an important concept - the relative shortage of donors and the need for organs," explained Dr. Nader Moazami, Surgical Director of Heart Transplantation and Mechanical Circulatory Support at NYU Langone Health. "The DCD process taps into potential donors that have been used in the past for abdominal transplants but not for cardiac patients. We are excited about expanding the potential donor pool in the United States."

Preliminary data shows that DCD heart transplant with CPB allows immediate reperfusion and complete unloading of the heart, correction of metabolic derangements and real-time in-situ assessment of the heart prior to acceptance. Post-transplant cardiac function has been excellent in all cases with excellent early survival. This approach is readily adoptable for more widespread use, and will increase donor availability in the United States. During the study, six livers and 14 kidneys were recovered from the same donors, which could indicate success in increasing organ availability for non-cardiac patients as well.

Because the DCD process allows surgeons to resuscitate and assess the organ better before transplantation, the strategy should improve outcomes for patients. "This is the first study of DCD-NRP transplantation in the United States, and we already have many patients at least six months out from the transplant experiencing positive results," explained Deane Smith, MD, Assistant Professor of Cardiothoracic Surgery and Surgical Director of the Adult ECMO Program at NYU Langone Health. "Using traditional methods, there is not an effective way to assess the heart on the pump, but using DCD-NRP, we can measure cardiac output and hemodynamics before a decision is made to accept the heart, and hopefully we will improve the quality of the other organs.

Boston, MA (May 1, 2021) - A new study presented today at the AATS 101st Annual Meeting, found that the percentage of patients undergoing esophagectomy for cancer who suffer Venous Thromboembolism (VTE) post-operatively is much higher than previously reported, with as many as 24 percent suffering from Deep Vein Thrombosis (DVT) or Pulmonary Embolism (PE). Six-month mortality for patients with VTE was 17.6 percent compared to 2.1 percent for those without.

Venous Thromboembolism (VTE) is a common, potentially preventable post-operative complication leading to significant morbidity and mortality. Esophagectomy patients are amongst the highest risk groups for VTE due to disease burden, magnitude of surgery and high rate of perioperative morbidity. The study aimed to quantify the true incidence of VTE post esophagectomy, associated risk factors, and the impact of VTE on patients' outcomes.

Patients undergoing esophagectomy for malignancy in eight tertiary-care centers between November 2017 and March 2020 were enrolled in a prospective cohort study. All patients received guideline based VTE prophylaxis until hospital discharge and underwent bilateral lower-extremity venous-doppler ultrasonography (DUS) prior to discharge, then Computed Chest Tomography-pulmonary embolus protocol (CT-PE) as well as DUS at 30 and 90-days post-op, and DUS at 60 days. D-dimer levels were measured at each interval and patients were followed for 6 months postoperatively.

According to Yaron Shargall, M.D., FRCSC, professor and chair of the division of Thoracic Surgery at McMaster University and study leader, despite the fact that all patients were treated with VTE prophylaxis according to best practices, a high proportion would have been discharged home with VTE under standard protocols, or would have developed VTE after discharge. "When we followed this cohort of patients for six months, we saw VTE events develop mostly within one month of surgery, but also as long as six months. Even more importantly, we found that those who developed VTE had a seven-fold increase in mortality at six months, the reasons for which are yet to be determined" says Shargall. "We are yet to define if active screening for VTE in all esophagectomy patients is really justified, and if a longer duration of VTE prophylaxis, beyond the hospital stay, will improve patients' outcomes" he added.

Researchers from University of Arizona and University of Utah published a new paper in the Journal of Marketing that examines why most scholarly research is misinterpreted by the public or never escapes the ivory tower and suggests that such research gets lost in abstract, technical, and passive prose.

The study, forthcoming in the Journal of Marketing, is titled "Marketing Ideas: How to Write Research Articles that Readers Understand and Cite" and is authored by Nooshin L. Warren, Matthew Farmer, Tiany Gu, and Caleb Warren.

From developing vaccines to nudging people to eat less, scholars conduct research that could change the world, but most of their ideas either are misinterpreted by the public or never escape the ivory tower.

Why does most academic research fail to make an impact? The reason is that many ideas in scholarly research get lost in an attic of abstract, technical, and passive prose. Instead of describing "spilled coffee" and "one-star Yelp reviews," scholars discuss "expectation-disconfirmation" and "post-purchase behavior." Instead of writing "policies that let firms do what they want have increased the gap between the rich and the poor," scholars write sentences like, "The rationalization of free-market capitalism has been resultant in the exacerbation of inequality." Instead of stating, "We studied how liberal and conservative consumers respond when brands post polarizing messages on social media," they write, "The interactive effects of ideological orientation and corporate sociopolitical activism on owned media engagement were studied."

Why is writing like this unclear? Because it is too abstract, technical, and passive. Scholars need abstraction to describe theory. Thus, they write about "sociopolitical activism" rather than Starbucks posting a "Black Lives Matter" meme on Facebook. They are familiar with technical terms, such as "ideological orientation," and they rely on them rather than using more colloquial terms such as "liberal or conservative." Scholars also want to sound objective, which lulls them into the passive voice (e.g., the effects... were studied) rather than active writing (e.g., "we studied the effects..."). Scholars need to use some abstract, technical, and passive writing. The problem is that they tend to overuse these practices without realizing it.

When writing is abstract, technical, and passive, readers struggle to understand it. In one of the researchers' experiments, they asked 255 marketing professors to read the first page of research papers published in the Journal of Marketing (JM), Journal of Marketing Research (JMR), and Journal of Consumer Research (JCR). The professors understood less of the papers that used more abstract, technical, and passive writing compared to those that relied on concrete, non-technical, and active writing.

As Warren explains, "When readers do not understand an article, they are unlikely to read it, much less absorb it and be influenced by its ideas. We saw this when we analyzed the text of 1640 articles published in JM, JMR, and JCR between 2000 and 2010. We discovered that articles that relied more on abstract, technical, and passive writing accumulated fewer citations on both Google Scholar and the Web of Science." An otherwise average JM article that scored one standard deviation lower (clearer) on our measures of abstract, technical, and passive writing accumulated approximately 157 more Google Scholar citations as of May 2020 than a JM article with average writing.

Why do scholars write unclearly? There is an unlikely culprit: knowledge. Conducting good research requires authors to know a lot about their work. It takes years to create research that meaningfully advances scientific knowledge. Consequently, academic articles are written by authors who are intimately familiar with their topics, methods, and results. Authors, however, often forget or simply do not realize that potential readers (e.g., PhD students, scholars in other sub-disciplines, practicing professionals, etc.) are less familiar with the intricacies of the research, a phenomenon called the curse of knowledge.

The research team explores whether the curse of knowledge might be enabling unclear writing by asking PhD students to write about two research projects. The students wrote about one project on which they were the lead researcher and another project led by one of their colleagues. The students reported that they were more familiar with their own research than their colleague's research. They also thought that they wrote more clearly about their own research, but they were mistaken. In fact, the students used more abstraction, technical language, and passive voice when they wrote about their own research than when they wrote about their colleague's research.

"To make a greater impact, scholars need to overcome the curse of knowledge so they can package their ideas with concrete, technical, and active writing. Clear writing gives ideas the wings needed to escape the attics, towers, and increasingly narrow halls of their academic niches so that they can reduce infection, curb obesity, or otherwise make the world a better place," says Farmer.

WHAT:

In a mouse study, National Institutes of Health researchers have identified and mapped a diverse spectrum of motor neurons along the spinal cord. These neurons, which send and receive messages throughout the body, include a subset that is susceptible to neurodegenerative diseases. Created with a genetic sequencing technique, the atlas reveals 21 subtypes of neurons in discrete areas throughout the spinal cord and offers insight into how these neurons control movement, how they contribute to the functioning of organ systems and why some are disproportionately affected in neurodegenerative diseases.

The study was led by Claire Le Pichon, Ph.D., head of the Unit on the Development of Neurodegeneration at NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). It appears in Nature Communications.

Spinal cord neurons are responsible for all types of movement in the body, ranging from voluntary movements like walking to the involuntary constriction and relaxation of the stomach as it processes its contents. Traditionally, scientists categorize these neurons into three main types: skeletal motor neurons, visceral motor neurons and interneurons. Previous research suggests there are additional subtypes within these three categories and that some of these subtypes may be more vulnerable to neurodegenerative diseases than others. For example, diseases like spinal muscular atrophy and amyotrophic lateral sclerosis, or ALS, affect only certain types of skeletal muscle neurons.

In the current study, the team used a technique called single nucleus RNA sequencing to identify 21 subtypes of spinal cord neurons in mice. The findings reveal highly distinct subtypes, especially among motor neurons that control the glands and internal organs. The team also discovered that visceral motor neurons extend higher up along the spinal column than previously known. The authors believe these motor neurons may be newly discovered subtypes with unknown functions.

Boston, MA (April 30, 2021) - A new study, presented today at the AATS 101st Annual Meeting, shows that non-invasive cell-free DNA tests can reduce the need for regular surveillance biopsies to detect early rejection in heart transplant patients. The study was the first of its kind to be performed on both adult and pediatric patients.

Pediatric and adult heart transplant recipients were recruited prospectively from eight participating sites and followed longitudinally for at least 12 months with serial plasma samples collected immediately prior to all endomyocardial biopsies. Structured biopsy results and clinical data were collected and monitored by an independent clinical research organization (CRO).

For all patients taken together in comparison to the composite biopsy outcome using repeated measures, donor fraction (DF) cfDNA at a pre-defined cut point of 0.14 had a sensitivity of 67%, a specificity of 79%, a PPV of 34% and a NPV of 94% with an area under the curve (AUC) of 0.78 (p

"Our multicenter group has demonstrated the utility of a clinically viable test for the donor-derived fraction of cell-free DNA, which can vastly reduce the need for routine surveillance biopsies," explained Marc Richmond, MD, MS, Associate Professor of Pediatrics at Columbia University Medical Center, and the Associate Medical Director of the Program for Pediatric Cardiomyopathy, Heart Failure and Transplantation. "Our consortium of eight centers is continuing to analyze additional data and put forth new studies using this technology." This assay is clinically usable at any time point after seven days post-transplant and can have a turnaround time of as little as 24 hours. Future studies will include clinical protocols that further assess how this method compares to current practice standards.

Boston, MA (April 30, 2021) - A new study, presented today at the AATS 101st Annual Meeting, found that severely ill COVID-19 patients treated with ECMO did not suffer worse long-term outcomes than other mechanically-ventilated patients. The multidisciplinary team included cardio thoracic surgeons, critical care doctors, medical staff at long-term care facilities, physical therapists and other specialists, and followed patients at five academic centers: University of Colorado; University of Virginia; University of Kentucky; Johns Hopkins University; and Vanderbilt University.

Survivors of critical illness are at high risk for long-term physical, psychological, and cognitive deficits. Extracorporeal membrane oxygenation (ECMO) shows promising survival benefit for select patients with COVID-19. However, its impact on long-term recovery was unknown. The study measured physical, psychological, and cognitive deficits in in 46 patients who were canulated for ECMO compared to a control group of 262 mechanically ventilated patients who did not receive ECMO.

The multi-disciplinary team conducted a retrospective analysis of mechanically ventilated patients with COVID-19 admitted between March and May 2020. Data were available for all mechanically ventilated patients from three sites, while all five sites provided ECMO patient data. Survivors had access to a multi-disciplinary post-intensive care unit recovery clinic for long-term care. Physical, psychological, and cognitive deficits were measured using validated instruments during follow up. Patient characteristics and long-term outcomes were compared based on ECMO status.

The study found no significant difference in survival at discharge (69.6 percent ECMO vs. 69.9 percent non-ECMO.) Of the 215 survivors across both groups, 93.9 percent were residing at home, 16.1 percent had returned to work or usual activity and 26.2 percent were still using supplemental oxygen; these rates did not differ significantly based on ECMO status. Rates of physical, psychological and cognitive deficits did not differ significantly.

"The initial guidance for ECMO in COVID was helpful and saved a lot of lives, and not to their detriment, which is very encouraging," explained Dr. Jessica Rove, Assistant Professor, Cardiothoracic Surgery at University of Colorado Anschutz Medical Campus, and Section Chief, Cardiac Surgery, Rocky Mountain Regional VA Medical Center. "This multidisciplinary collaboration is committed to examining long-term outcomes beyond survival, and early results look promising. This may help to further refine who should receive ECMO and may increase the rate of positive outcomes."

Further research will continue to follow patients and measure outcomes over the longer term. Dr. Lauren Taylor, fellow at University of Colorado Anschutz Medical Campus explained, "It is exciting that we now have the long term outcomes of these patients and that they are so promising. Further study of these patients over the long term can help to further refine who we are canulating for ECMO, leading to better outcomes for all."

A new study finds Black patients are more likely to die after their heart bypass surgery if they're at a hospital where some care teams see mostly white patients and others see mostly Black patients. On the other hand, mortality rates are comparable between Black and white patients after heart bypass surgery when the teams of health care providers at their hospitals all care for patients of all races.

Some level of care team segregation within hospitals was very common, and the findings bring up another angle to better understand racial inequities in surgical outcomes, says co-first author John Hollingsworth, M.D., M.Sc., a professor of urology at Michigan Medicine and of health management and policy at the University of Michigan School of Public Health.

Previous studies have already shown that mortality after heart bypass surgery is higher overall in Black patients than white patients, but known factors such as access to care and use of lower resourced hospitals don't fully explain the disparities.

Hollingsworth and colleagues' new paper reviewed Medicare claims from more than 12,000 heart bypass procedures between 2008 and 2014. The data included claims from 72 hospitals across the country where at least 10 Black patients and at least 10 white patients underwent heart bypass surgery over the study interval.

Researchers used social network analysis to see where provider overlap happened--or didn't happen--between Black and white heart bypass patients and create a provider care team segregation score for each hospital.

"In the Medicare population, there is a lack of overlap in the composition of the provider care teams that treat Black and white patients undergoing heart bypass surgery in the same hospital," Hollingsworth says. "Such provider care team segregation is associated with higher operative mortality for this procedure among Black patients."

Researchers say the reasons for this segregation may include patient preference, in which people prefer to have a care provider who looks like them; admission priority, in which Black patients are more likely to come from the emergency room for their heart bypass than schedule it in advance as an elective surgery; and effects of structural racism on the process of assigning patients to provider care teams, which includes a variety of decisions that don't always get shared or explained.

Co-senior author Brahmajee Nallamothu, M.D., M.P.H., a professor of internal medicine and an interventional cardiologist at the Michigan Medicine Frankel Cardiovascular Center, says the findings point to the need for in-depth study of provider care team segregation as part of the effort to reduce health care inequities.

LA JOLLA--(April 30, 2021) Scientists have known for a while that SARS-CoV-2's distinctive "spike" proteins help the virus infect its host by latching on to healthy cells. Now, a major new study shows that the virus spike proteins (which behave very differently from those safely encoded by vaccines) also play a key role in the disease itself.

The paper, published on April 30, 2021, in Circulation Research, also shows conclusively that COVID-19 is a vascular disease, demonstrating exactly how the SARS-CoV-2 virus damages and attacks the vascular system on a cellular level. The findings help explain COVID-19's wide variety of seemingly unconnected complications, and could open the door for new research into more effective therapies.

"A lot of people think of it as a respiratory disease, but it's really a vascular disease," says Assistant Research Professor Uri Manor, who is co-senior author of the study. "That could explain why some people have strokes, and why some people have issues in other parts of the body. The commonality between them is that they all have vascular underpinnings."

Salk researchers collaborated with scientists at the University of California San Diego on the paper, including co-first author Jiao Zhang and co-senior author John Shyy, among others.

While the findings themselves aren't entirely a surprise, the paper provides clear confirmation and a detailed explanation of the mechanism through which the protein damages vascular cells for the first time. There's been a growing consensus that SARS-CoV-2 affects the vascular system, but exactly how it did so was not understood. Similarly, scientists studying other coronaviruses have long suspected that the spike protein contributed to damaging vascular endothelial cells, but this is the first time the process has been documented.

In the new study, the researchers created a "pseudovirus" that was surrounded by SARS-CoV-2 classic crown of spike proteins, but did not contain any actual virus. Exposure to this pseudovirus resulted in damage to the lungs and arteries of an animal model--proving that the spike protein alone was enough to cause disease. Tissue samples showed inflammation in endothelial cells lining the pulmonary artery walls.

The team then replicated this process in the lab, exposing healthy endothelial cells (which line arteries) to the spike protein. They showed that the spike protein damaged the cells by binding ACE2. This binding disrupted ACE2's molecular signaling to mitochondria (organelles that generate energy for cells), causing the mitochondria to become damaged and fragmented.

Previous studies have shown a similar effect when cells were exposed to the SARS-CoV-2 virus, but this is the first study to show that the damage occurs when cells are exposed to the spike protein on its own.

"If you remove the replicating capabilities of the virus, it still has a major damaging effect on the vascular cells, simply by virtue of its ability to bind to this ACE2 receptor, the S protein receptor, now famous thanks to COVID," Manor explains. "Further studies with mutant spike proteins will also provide new insight towards the infectivity and severity of mutant SARS CoV-2 viruses."

The researchers next hope to take a closer look at the mechanism by which the disrupted ACE2 protein damages mitochondria and causes them to change shape.

While the CRISPR-Cas9 gene editing system has become the poster child for innovation in synthetic biology, it has some major limitations. CRISPR-Cas9 can be programmed to find and cut specific pieces of DNA, but editing the DNA to create desired mutations requires tricking the cell into using a new piece of DNA to repair the break. This bait-and-switch can be complicated to orchestrate, and can even be toxic to cells because Cas9 often cuts unintended, off-target sites as well.

Alternative gene editing techniques called recombineering instead perform this bait-and-switch by introducing an alternate piece of DNA while a cell is replicating its genome, efficiently creating genetic mutations without breaking DNA. These methods are simple enough that they can be used in many cells at once to create complex pools of mutations for researchers to study. Figuring out what the effects of those mutations are, however, requires that each mutant be isolated, sequenced, and characterized: a time-consuming and impractical task.

Researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University and Harvard Medical School (HMS) have created a new gene editing tool called Retron Library Recombineering (RLR) that makes this task easier. RLR generates up to millions of mutations simultaneously, and "barcodes" mutant cells so that the entire pool can be screened at once, enabling massive amounts of data to be easily generated and analyzed. The achievement, which has been accomplished in bacterial cells, is described in a recent paper in PNAS.

"RLR enabled us to do something that's impossible to do with CRISPR: we randomly chopped up a bacterial genome, turned those genetic fragments into single-stranded DNA in situ, and used them to screen millions of sequences simultaneously," said co-first author Max Schubert, Ph.D., a postdoc in the lab of Wyss Core Faculty member George Church, Ph.D. "RLR is a simpler, more flexible gene editing tool that can be used for highly multiplexed experiments, which eliminates the toxicity often observed with CRISPR and improves researchers' ability to explore mutations at the genome level."

Retrons: from enigma to engineering tool

Retrons are segments of bacterial DNA that undergo reverse transcription to produce fragments of single-stranded DNA (ssDNA). Retrons' existence has been known for decades, but the function of the ssDNA they produce flummoxed scientists from the 1980s until June 2020, when a team finally figured out that retron ssDNA detects whether a virus has infected the cell, forming part of the bacterial immune system.

While retrons were originally seen as simply a mysterious quirk of bacteria, researchers have become more interested in them over the last few years because they, like CRISPR, could be used for precise and flexible gene editing in bacteria, yeast, and even human cells.

"For a long time, CRISPR was just considered a weird thing that bacteria did, and figuring out how to harness it for genome engineering changed the world. Retrons are another bacterial innovation that might also provide some important advances," said Schubert. His interest in retrons was piqued several years ago because of their ability to produce ssDNA in bacteria - an attractive feature for use in a gene editing process called oligonucleotide recombineering.

Recombination-based gene editing techniques require integrating ssDNA containing a desired mutation into an organism's DNA, which can be done in one of two ways. Double-stranded DNA can be physically cut (with CRISPR-Cas9, for example) to induce the cell to incorporate the mutant sequence into its genome during the repair process, or the mutant DNA strand and a single-stranded annealing protein (SSAP) can be introduced into a cell that is replicating so that the SSAP incorporates the mutant strand into the daughter cells' DNA.

"We figured that retrons should give us the ability to produce ssDNA within the cells we want to edit rather than trying to force them into the cell from the outside, and without damaging the native DNA, which were both very compelling qualities," said co-first author Daniel Goodman, Ph.D., a former Graduate Research Fellow at the Wyss Institute who is now a Jane Coffin Childs Postdoctoral Fellow at UCSF.

Another attraction of retrons is that their sequences themselves can serve as "barcodes" that identify which individuals within a pool of bacteria have received each retron sequence, enabling dramatically faster, pooled screens of precisely-created mutant strains.

To see if they could actually use retrons to achieve efficient recombineering with retrons, Schubert and his colleagues first created circular plasmids of bacterial DNA that contained antibiotic resistance genes placed within retron sequences, as well as an SSAP gene to enable integration of the retron sequence into the bacterial genome. They inserted these retron plasmids into E. coli bacteria to see if the genes were successfully integrated into their genomes after 20 generations of cell replication. Initially, less than 0.1% of E. coli bearing the retron recombineering system incorporated the desired mutation.

To improve this disappointing initial performance, the team made several genetic tweaks to the bacteria. First, they inactivated the cells' natural mismatch repair machinery, which corrects DNA replication errors and could therefore be "fixing" the desired mutations before they were able to be passed on to the next generation. They also inactivated two bacterial genes that code for exonucleases - enzymes that destroy free-floating ssDNA. These changes dramatically increased the proportion of bacteria that incorporated the retron sequence, to more than 90% of the population.

Name tags for mutants

Now that they were confident that their retron ssDNA was incorporated into their bacteria's genomes, the team tested whether they could use the retrons as a genetic sequencing "shortcut," enabling many experiments to be performed in a mixture. Because each plasmid had its own unique retron sequence that can function as a "name tag", they reasoned that they should be able to sequence the much shorter retron rather than the whole bacterial genome to determine which mutation the cells had received.

First, the team tested whether RLR could detect known antibiotic resistance mutations in E coli. They found that it could - retron sequences containing these mutations were present in much greater proportions in their sequencing data compared with other mutations. The team also determined that RLR was sensitive and precise enough to measure small differences in resistance that result from very similar mutations. Crucially, gathering these data by sequencing barcodes from the entire pool of bacteria rather than isolating and sequencing individual mutants, dramatically speeds up the process.

Then, the researchers took RLR one step further to see if it could be used on randomly-fragmented DNA, and find out how many retrons they could use at once. They chopped up the genome of a strain of E. coli highly resistant to another antibiotic, and used those fragments to build a library of tens of millions of genetic sequences contained within retron sequences in plasmids. "The simplicity of RLR really shone in this experiment, because it allowed us to build a much bigger library than what we can currently use with CRISPR, in which we have to synthesize both a guide and a donor DNA sequence to induce each mutation," said Schubert.

This library was then introduced into the RLR-optimized E coli strain for analysis. Once again, the researchers found that retrons conferring antibiotic resistance could be easily identified by the fact that they were enriched relative to others when the pool of bacteria was sequenced.

"Being able to analyze pooled, barcoded mutant libraries with RLR enables millions of experiments to be performed simultaneously, allowing us to observe the effects of mutations across the genome, as well as how those mutations might interact with each other," said senior author George Church, who leads the Wyss Institute's Synthetic Biology Focus Area and is also a Professor of Genetics at HMS. "This work helps establish a road map toward using RLR in other genetic systems, which opens up many exciting possibilities for future genetic research."

Another feature that distinguishes RLR from CRISPR is that the proportion of bacteria that successfully integrate a desired mutation into their genome increases over time as the bacteria replicate, whereas CRISPR's "one shot" method tends to either succeed or fail on the first try. RLR could potentially be combined with CRISPR to improve its editing performance, or could be used as an alternative in the many systems in which CRISPR is toxic.

More work remains to be done on RLR to improve and standardize editing rate, but excitement is growing about this new tool. RLR's simple, streamlined nature could enable the study of how multiple mutations interact with each other, and the generation of a large number of data points that could enable the use of machine learning to predict further mutational effects.

"This new synthetic biology tool brings genome engineering to an even higher levels of throughput, which will undoubtedly lead to new, exciting, and unexpected innovations," said Don Ingber, M.D., Ph.D., the Wyss Institute's Founding Director. Ingber is also the Judah Folkman Professor of Vascular Biology at HMS and Boston Children's Hospital, and Professor of Bioengineering at the Harvard John A. Paulson School of Engineering and Applied Sciences.