One key finding of interest to clinical laboratory scientists is that this research study indicates that the human microbiome may more closely correlate with blood markers of metabolic disease than the genome of individuals
In the search for more sensitive diagnostic biomarkers (meaning the ability to detect disease with smaller samples and smaller quantities of the target biomarker), an international team of researchers has teased out a finding that a panel of multiple biomarkers in the human microbiome is more closely correlated with metabolic disease than genetic markers.
The team also discovered that the foods an individual ate had a more powerful impact on their microbiomes than their genes. The study participants included several sets of identical twins. The researchers found that identical twins shared only about 34% of the same gut microbes. People who were unrelated shared 30% of the same gut microbes.
This is a fascinating insight for pathologists and microbiologists involved in the study of the human microbiome for use in development of precision medicine clinical laboratory testing and drug therapies.
Microbiome Markers for Obesity, Heart Disease, and More
The study began in 2018, when an international team of researchers analyzed the gut microbiomes, diets, and blood biomarkers for cardiometabolic health obtained from 1,100 mostly healthy adults in the United Kingdom (UK) and the United States (US). They collected blood samples from the participants before and after meals to examine blood sugar levels, hormones, cholesterol, and inflammation levels. Sleep and activity levels also were monitored. Participants had to wear a continuous glucose monitor for two weeks during the research period.
The scientists discovered that the composition of a healthy gut microbiome is strongly linked to certain foods, food groups, nutrients, and diet composition. They identified markers for obesity, impaired glucose tolerance, and cardiovascular disease in the gut bacteria.
“When you eat, you’re not just nourishing your body, you’re feeding the trillions of microbes that live inside your gut,” genetic epidemiologist Tim Spector, MD, FmedSCi, told Labroots. Spector is a professor of genetic epidemiology at King’s College London and one of the authors of the study.
The scientists found that a diet rich in nutrient-dense, whole foods was more beneficial to a healthy gut microbiome, which can be an indicator of good health. Individuals who ate minimally processed foods, such as vegetables, nuts, eggs, and seafood were more likely to have healthy gut bacteria than individuals who consumed large amounts of highly processed foods, like juices and other sweetened beverages, processed meats, and refined grains and foods that were high in added sugars and salt.
“It goes back to the age-old message of eating as many whole and unprocessed foods as possible,” Sarah Berry, PhD, a nutrition scientist at King’s College London and a co-author of the study told The New York Times. “What this research shows for the first time is the link between the quality of the food we’re eating, the quality of our microbiomes, and ultimately our health outcomes,” she added.
The researchers concluded that heavily processed foods tend to contain very minimal amounts of fiber, a macronutrient that helps promote good bacteria in the gut microbiome and leads to better metabolic and cardiovascular health.
They found that people who had healthy blood sugar levels following a meal had higher levels of good bacteria called Prevotella copri, a genus of gram-negative bacteria, and Blastocystis, a genus of single-celled heterokont parasites, present in their guts. These bacteria are associated with lower levels of visceral fat, which accumulates around internal organs and increases risk of heart disease.
These “good” microbes also are affiliated with lower levels of inflammation, better blood sugar control, and lower spikes in blood fat and cholesterol levels after meals.
“We were surprised to see such large, clear groups of what we informally call ‘good’ and ‘bad’ microbes emerging from our analysis,” Nicola Segata, PhD (above), told News Medical. Segata is a professor and principal investigator at the Computational Metagenomics Lab at the University of Trento in Italy, and co-author of the study. “It is also exciting to see that microbiologists know so little about many of these microbes that they are not even named yet. This is now a big area of focus for us, as we believe they may open new insights in the future into how we could use the gut microbiome as a modifiable target to improve human metabolism and health,” he added. Pathologists and clinical laboratory scientists who read Dark Daily are already familiar with the plethora of ways the human microbiome is being studied for use in diagnostic testing and drug therapy. (Photo copyright: University of Trento.)
The study also found that different people have wildly varying metabolic responses to the same foods, partially due to the types of bacteria residing in their gut microbiome. The consumption of some foods is better for overall health than other foods, but there is no definitive, one-size-fits-all diet that works for everyone.
“What we found in our study was that the same diet in two different individuals does not lead to the same microbiome, and it does not lead to the same metabolic response. There is a lot of variation,” Andrew Chan, MD, Professor of Medicine at Harvard Medical School, told The New York Times. Chan is also Chief of the Clinical and Translational Epidemiology Unit at Massachusetts General Hospital and co-author of the study.
Small Changes in Diet, Big Impact to Health
The team is now planning a clinical trial to test whether changes in diet can alter levels of good and bad microbes in the gut. If proven to be true, such information could help clinicians design personalized nutritional plans that would enable individuals to improve their gut microbiome and their overall health.
“As a nutritional scientist, finding novel microbes that are linked to specific foods, as well as metabolic health, is exciting,” Berry told News Medical. “Given the highly personalized composition of each individual’s microbiome, our research suggests that we may be able to modify our gut microbiome to optimize our health by choosing the best foods for our unique biology.
“We think there are lots of small changes that people can make that can have a big impact on their health that might be mediated through the microbiome,” Berry told The New York Times.
More research and clinical trials are needed before diagnostic tests that use microbiome biomarkers to detect metabolic diseases can be developed. But these early research findings are a sign to pathologists and clinical laboratory managers that microbiome-based assays may come to play a more significant role in the early detection of several metabolic diseases.
Such a test, if proved safe and accurate for clinical use, could be a useful diagnostic tool for anatomic pathologists
What would it mean to anatomic pathology if breast cancer could be diagnosed in an hour from a fine needle aspiration (FNA) rather than a core biopsy? A new test created by researchers affiliated with Massachusetts General Hospital in Boston may be just such a game changer. Especially in remote locations where clinical laboratory resources are in short supply.
Regardless of how the next round of research and clinical studies turn out, one reason this development is significant is that it demonstrates how newer technologies and analytical software are being combined to create a faster diagnostic test for different types of cancer.
Another benefit to this research is that it may utilize simpler, less expensive instruments. In fact, the researchers said this test can be performed for about $5. For these reasons, pathologists may want to follow the progress of these researchers as they work to improve this test so it can be used in clinical care.
Affordable Image Cytometry of FNA Specimens
Though still in development, the new image cytometry system, dubbed CytoPAN, has demonstrated the ability to diagnose breast cancer within a one-hour time frame, and, according to the study published in Science Translational Medicine, “is devoid of moving parts for stable operations, harnesses optimized antibody kits for multiplexed analysis, and offers a user-friendly interface with automated analysis for rapid diagnoses.”
The international researcher team included scientists from:
“Here, we report the development and validation of an affordable image cytometry system that allows automated and same-day molecular analyses of fine needle aspiration (FNA) specimens. Termed CytoPAN, for portable fluorescence-based image cytometry analyzer, the system performs multichannel imaging for cancer diagnosis and subtyping,” the researchers wrote.
The CytoPAN technique is minimally invasive, they note, and only requires a few cellular specimens to determine if breast cancer cells are present, with results available in one hour.
The researchers are hopeful the CytoPAN diagnostic tool (above) can be a valuable resource in developing countries and remote areas where patients face long wait times before receiving a cancer diagnosis. In these areas, diagnoses typically come after advanced symptoms, such as palpable mass lesions and malaise, become present, which can have a negative impact on patientoutcomes. And anatomic pathologists worldwide would benefit greatly from such an advance in cancer diagnostics. (Photo copyright: Jouha Min, Lip Ket Chin Center for Systems Biology, Massachusetts General Hospital.)
“Unfortunately, in many low- and middle-income countries, [breast cancer] diagnosis often takes an extraordinarily long time—up to a few months—due to a lack of specialists and limited laboratory infrastructure,” Hyungsoon Im, PhD, Assistant Professor at Harvard Medical School and one of the researchers involved in the project, told United Press International (UPI).
“From a public health aspect, it is critically important to develop new diagnostic methods that overcome these barriers,” he added.
Because FNA testing is less invasive than surgical biopsy collection, it has fewer complications and is generally considered safe. Thus, it is “feasible to be performed even in resource-limiting settings at much lower costs,” Im told UPI. “This could lead to earlier treatment and accelerate new drug testing in clinical trials.”
CytoPAN Testing and Additional Trials
The researchers tested CytoPAN on 68 breast cancer patients in South Korea.
“To determine the clinical utility of the approach,” they wrote in the published study, “we next conducted a prospective clinical study in which the FNA could be directly compared to conventional pathology results. We enrolled treatment-native patients at the Kyungpook National University Chilgok Hospital (Daegu, South Korea) and who were referred for primary surgery. All patients consented to have a preoperative breast FNA before clinically indicated surgery. The breast masses were visualized by ultrasound or computed tomography, and a coaxial needle was introduced through which FNA samples (CytoPAN) and core biopsies were obtained. Surgical specimens and/or core biopsies were processed by routine pathology and served as the gold standard.”
The CytoPAN platform detected the presence of breast cancer cells with a 100% accuracy, using as few as 50 harvested cells per collected specimen.
The test also successfully identified two key breast cancer biomarkers:
“We are also preparing additional trials in the US and other countries,” Im told UPI. “The success in those trials will (hopefully) accelerate … widespread adoption of the technology.”
The researchers are currently testing CytoPAN on a larger number of patients in Botswana, with funding from the US federal National Institutes of Health (NIH).
According to the American Cancer Society (ACS), approximately 300,000 individuals are diagnosed with breast cancer annually in the US. The Union for International Cancer Control (UICC) states on their website that, globally, there are more than two million new cases of breast cancer diagnosed each year. And more than 600,000 people died from breast cancer worldwide in 2018. A disproportionate number of those deaths occurred in developing countries that have limited resources to diagnose and treat the disease.
Additional Research for Other Applications in Cancer Testing and Pathology
The new CytoPAN technology requires minimal training, according to the researchers, and only costs about $5 per test kit. This is substantially less expensive than the price associated with other tests available on the market, UPI noted.
Though additional research and clinical trials are needed before CytoPAN will be available for widespread clinical use, a cost-effective, relatively non-invasive test that can accurately diagnose cancer within an hour would be transformational for anatomic pathology and, potentially, could save many lives.
Breakthrough assay a ‘tenfold improvement over any prior assay for TERT mutations in the blood for brain tumors,’ MGH says in an affirmation of a diagnostic technology clinical labs might soon use
In recent years, investors have poured tens of millions of dollars into companies that promised to create non-invasive cancer tests which use liquid biopsy technology. Medical laboratory scientists even watched some of these companies hype their particular liquid biopsy tests before clinical studies generated data demonstrating that these tests produced accurate, reliable, and reproducible results.
For diagnosing cancer, a liquid biopsy test typically uses a blood sample with the goal of finding and identifying circulating tumor cells. Harvard Medical School researchers at Massachusetts General Hospital (MGH) believe they have developed just such a blood test. Their assay utilizes an enhanced form of liquid biopsy to detect and monitor one of the more prevalent types of brain tumor in adults—a glioma—and, according to a Harvard news release, can detect the presence of glioma at a significantly higher “overall sensitivity” than other similar liquid-biopsy tests.
Gliomas start in glia cells contained in the brain or spine. They account for about 30% of all brain and central nervous system tumors and 80% of all malignant brain tumors.
During their study, MGH researchers compared blood samples and tumor biopsy tissues from patients diagnosed with a glioma. They discovered that an assay they developed—a droplet digital polymerase chain reaction (ddPCR) blood test—could detect and monitor two types of telomerase reverse transcriptase (TERT) promoter gene mutations—C228T and C250T. These two gene mutations promote cancer growth and are present in more than 60% of all gliomas. The mutations are also present in 80% of all high-grade gliomas, which are the most aggressive and life-threatening types of the cancer.
In the press release, instructor in Neurosurgery at MGH and one of the study’s authors, Leonora Balaj, PhD, said, “By ‘supercharging’ our ddPCR assay with novel technical improvements, we showed for the first time that the most prevalent mutation in malignant gliomas can be detected in blood, opening a new landscape for detection and monitoring of the tumors.”
Bob Carter, MD, PhD (above), is neurosurgical oncologist and Chief of Neurosurgery at MGH, a Professor of Neurosurgery at Harvard Medical School, and one of the study’s authors. In the MGH press release he said, “We envision the future integration of tests like this one into the clinical care of our patients with brain tumors. For example, if a patient has a suspected mass on MRI scanning, we can take a blood sample before the surgery and assess the presence of the tumor signature in the blood and then use this signature as a baseline to monitor as the patient later receives treatment, both to gauge response to the treatment and gain early insight into any potential recurrence.” What Carter describes is precision medicine and could open new diagnostic opportunities for anatomic pathology groups and clinical laboratories. (Photo copyright: Massachusetts General Hospital.)
MGH’s Ten-Fold Improvement over Previous ddPCR Assays
A liquid biopsy is the sampling and analysis of non-solid tissue in the body—primarily blood. MGH’s liquid-biopsy method detects cancer by examining fragments of tumor DNA circulating in the bloodstream. Since the technique is mostly non-invasive, tests can be performed more frequently to track tumors and mutations and monitor treatment progression. Prior to this new method, brain tumors had been difficult to detect using liquid biopsies.
“Liquid biopsy is particularly challenging in brain tumors because mutant DNA is shed into the bloodstream at a much lower level than any other types of tumors,” Balaj said in the press release.
However, MGH’s new ddPCR assay has an overall sensitivity rate of 62.5% and a specificity of 90%, which represents a tenfold improvement over prior assays for TERT mutations in the blood.
And when testing the performance of the ddPCR assay in tumor tissue, the MGH researchers discovered their results were the same as results from a previous independently-performed clinical laboratory assessment of TERT mutations within collected tumor specimens. They also found that their assay could detect TERT mutations when looking at blood plasma samples collected at other facilities.
The researchers believe that their test could be performed in most clinical laboratories and can be utilized to follow the course of disease in cancer patients. The MGH researcher’s goal is to expand and adapt the blood test to diagnose, differentiate, and monitor other types of brain tumors in addition to gliomas.
Of course, more research will be needed before MGH’s new assay can become a vital tool in the fight against disease. However, this type of genetic analysis may soon provide pathologists with new techniques to more accurately diagnose and monitor cancers, and to provide healthcare providers with valuable data regarding which therapies would be the most beneficial for individual patients, a key element of precision medicine.
Clinical laboratories involved in genetic testing may find this welcomed news, after a pair of studies conducted in 2019 raised concerns about CRISPR base editing. The researchers of those studies observed that it “causes a high number of unpredictable mutations in mouse embryos and rice,” Chemical and Engineering News (C&EN) reported, adding, “Other groups have raised concerns about off-target mutations caused when the traditional CRISPR-Cas9 form of gene editing cuts DNA at a location that it wasn’t supposed to touch. The results of the new studies are surprising, however, because scientists have lauded base editors as one of the most precise forms of gene editing yet.”
Nevertheless, UC Berkeley’s latest breakthrough is expected to drive development of new and more accurate CRISPR-Cas genome-editing tools, which consist of base editors as well as nucleases, transposases, recombinases, and prime editors.
Understanding CRISPR Base Editors At a ‘Deeper Level’
Harvard University Chemistry and Chemical Biology Professor David Liu, PhD, who co-authored the study, explained the significance of this latest discovery.
“While base editors are now widely used to introduce precise changes in organisms ranging from bacteria to plants to primates, no one has previously observed the three-dimensional molecular structure of a base editor,” he said in a UC Berkeley news release. “This collaborative project reveals the beautiful molecular structure of a state-of-the-art highly-active base editor—ABE8e—caught in the act of engaging a target DNA site.”
UC Berkeley Professor Jennifer Doudna, PhD (above), who served as senior author of the study, says scientists may now have the information necessary to refine base editors and improve their precision and genome-targeting ability. “This structure helps us understand base editors at a much deeper level,” she said in the UC Berkeley statement. “Now that we can see what we’re working with, we can develop informed strategies to improve the system.” (Photo copyright: UC Berkeley.)
Jennifer Doudna, PhD, UC Berkeley Professor, Howard Hughes Medical Institute Investigator, and senior author of the study, has been a leading figure in the development of CRISPR-Cas9 gene editing. In 2012, Doudna and Emmanuelle Charpentier, PhD, Founding, Scientific and Managing Director at Max Planck Unit for the Science of Pathogens in Berlin, led a team of researchers who “determined how a bacterial immune system known as CRISPR-Cas9 is able to cut DNA, and then engineered CRISPR-Cas9 to be used as a powerful gene editing technology.” In a 2017 news release, UC Berkeley noted that the work has been described as the “scientific breakthrough of the century.”
Viewing the Base Editor’s 3D Shape
CRISPR-Cas9 gene editing allows scientists to permanently edit the genetic information of any organism, including human cells, and has been used in agriculture as well as medicine. A base editor is a tool that manipulates a gene by binding to DNA and replacing one nucleotide with another.
According to the recent UC Berkeley news release, the research team used a “high-powered imaging technique called cryo-electron microscopy” to reveal the base editor’s 3D shape.
Genetic Engineering and Biotechnology News notes that, “The high-resolution structure is of ABE8e bound to DNA, in which the target adenine is replaced with an analog designed to trap the catalytic conformation. The structure, together with kinetic data comparing ABE8e to earlier ABEs [adenine base editors], explains how ABE8e edits DNA bases and could inform future base-editor design.”
The graphic above, taken from the UC Berkeley news release, shows the “3D structure of a base editor, comprised of the Cas9 protein (white and gray), which binds to a DNA target (teal and blue helix) complementary to the RNA guide (purple), and the deaminase proteins (red and pink), which switch out one nucleotide for another.” (Image and caption copyright: UC Berkeley.)
Knowing the Cas9 fusion protein’s 3D structure may help eliminate unintended off-target effects on RNA, extending beyond the targeted DNA. However, until now, scientists have been hampered by their inability to understand the base editor’s structure.
“If you really want to design truly specific fusion protein, you have to find a way to make the catalytic domain more a part of Cas9, so that it would sense when Cas9 is on the correct target and only then get activated, instead of being active all the time,” study co-first author Audrone Lapinaite, PhD, said in the news release. At the time of the study, Lapinaite was a postdoctoral fellow at UC Berkeley. She is now an assistant professor at Arizona State University.
“As a structural biologist, I really want to look at a molecule and think about ways to rationally improve it. This structure and accompanying biochemistry really give us that power,” added UC Berkeley postdoctoral fellow Gavin Knott, PhD, another study co-author. “We can now make rational predications for how this system will behave in a cell, because we can see it and predict how it’s going to break or predict ways to make it better.”
Clinical laboratory leaders and pathologists will want to monitor these new advances in CRISPR technology. Each breakthrough has the power to fuel development of cost-effective, rapid point-of-care diagnostics.
The KCL researchers’ new models for predicting which patients will need hospitalization and breathing support may be useful for pathologists and clinical laboratory scientists
One more window into understanding the SARS-CoV-2 coronavirus may have just opened. A British study identified six distinct “clusters” of symptoms that the research scientists believe may help predict which patients diagnosed with COVID-19 will require hospitalization and respiratory support. If further research confirms these early findings, pathologists and medical laboratory managers may gain new tools to diagnose infections faster and more accurately.
Launched in March in the United Kingdom and extended to the United States and Sweden, the app has attracted more than four million users who track their health and potential COVID symptoms on a daily basis.
Increased Accuracy in Predicting COVID-19 Hospitalizations
KCL researchers identified six distinct “types” of COVID-19, each distinguished by a particular cluster of symptoms. They include headaches, muscle pains, fatigue, diarrhea, confusion, loss of appetite, shortness of breath, and more. The researchers also found that COVID-19 disease progression and outcome also vary significantly between people, ranging from mild flu-like symptoms or a simple rash to severe or fatal conditions.
Using app data logged by 1,600 users in March and April, the researchers developed an algorithm that combined information on age, gender, body mass index (BMI), and pre-existing conditions with recorded symptoms from the onset of the illness through the first five days. The researchers then tested the algorithm using a second independent dataset of 1,000 users, logged in May.
In a news release, the KCL researchers identified the six clusters of symptoms as:
Flu-like with No Fever: Headache, loss of smell, muscle pains, cough, sore throat, chest pain, no fever.
Flu-like with Fever: Headache, loss of smell, cough, sore throat, hoarseness, fever, loss of appetite.
Gastrointestinal: Headache, loss of smell, loss of appetite, diarrhea, sore throat, chest pain, no cough.
Severe Level One, Fatigue: Headache, loss of smell, cough, fever, hoarseness, chest pain, fatigue.
Severe Level Two, Confusion: Headache, loss of smell, loss of appetite, cough, fever, hoarseness, sore throat, chest pain, fatigue, confusion, muscle pain.
Severe Level Three, Abdominal and Respiratory: Headache, loss of smell, loss of appetite, cough, fever, hoarseness, sore throat, chest pain, fatigue, confusion, muscle pain, shortness of breath, diarrhea, abdominal pain.
Using the data, the researchers were able to more accurately predict—78.8% versus 69.5%—which of the six symptom clusters placed patients at higher risk of requiring hospitalization and breathing support (ventilation or additional oxygen) than with prediction models based on personal characteristics alone. For example, nearly 50% of the patients in cluster six (Severe Level Three, Abdominal and Respiratory) ended up in the hospital, compared with 16% of those in cluster one (Flu-like with No Fever).
“These findings have important implications for care and monitoring of people who are most vulnerable to severe COVID-19,” Claire Steves, MD, PhD (above left), Clinical Senior Lecturer at King’s College London, said in the KCL news release. “If you can predict who these people are at day five, you have time to give them support and early interventions, such as monitoring blood oxygen and sugar levels, and ensuring they are properly hydrated—simple care that could be given at home, preventing hospitalizations and saving lives.” (Photo copyright: King’s College London.)
According to the Zoe website, the ongoing research is led by:
Prof. Tim Spector, FMedSci, Professor of Genetic Epidemiology at King’s College London and Director of TwinsUK, an adult registry of twins in the United Kingdom;
Andrew Chan, MD, Professor of Medicine at Harvard Medical School, Professor of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health and Chief of the Clinical and Translational Epidemiology Unit, CTEU Massachusetts General Hospital; and
Encouraging Everyone to Use the COVID-Symptom Study App
The study points out that—broadly speaking—people with cluster four, five, or six COVID-19 symptoms tended to be older and frailer and were more likely to be overweight and have pre-existing conditions, such as diabetes or lung disease, than those with cluster one, two, or three symptoms.
“Our study illustrates the importance of monitoring symptoms over time to make our predictions about individual risk and outcomes more sophisticated and accurate,” said lead researcher Carole Sudre, PhD (above), a Research Fellow at King’s College London and the study’s lead researcher, in the KCL news release. “This approach is helping us to understand the unfolding story of this disease in each patient so they can get the best care.” (Photo copyright: University College London.)
Tim Spector, FMedSci, Head of the Department of Twin Research and Genetic Epidemiology, and Professor of Genetic Epidemiology at King’s College London, encourages everyone to download the COVID Symptom Study app and help increase the data available to researchers.
“Data is our most powerful tool in the fight against COVID-19,” Spector said in the KCL news release. “We urge everyone to get in the habit of using the app daily to log their health over the coming months, helping us to stay ahead of any local hotspots or a second wave of infections.”
As the body of knowledge surrounding COVID-19 grows, clinical laboratory professionals would be well advised to remain informed on further research regarding not only the potential for COVID-19 variants to exist, but also the evolving guidance on infection prevention and testing.
