This breath test can detect liver disease earlier
A company in England has made a test that picks out the compounds from breath that reveal if people have liver disease.
Every year, around two million people worldwide die of liver disease. While some people inherit the disease, it’s most commonly caused by hepatitis, obesity and alcoholism. These underlying conditions kill liver cells, causing scar tissue to form until eventually the liver cannot function properly. Since 1979, deaths due to liver disease have increased by 400 percent.
The sooner the disease is detected, the more effective treatment can be. But once symptoms appear, the liver is already damaged. Around 50 percent of cases are diagnosed only after the disease has reached the final stages, when treatment is largely ineffective.
To address this problem, Owlstone Medical, a biotech company in England, has developed a breath test that can detect liver disease earlier than conventional approaches. Human breath contains volatile organic compounds (VOCs) that change in the first stages of liver disease. Owlstone’s breath test can reliably collect, store and detect VOCs, while picking out the specific compounds that reveal liver disease.
“There’s a need to screen more broadly for people with early-stage liver disease,” says Owlstone’s CEO Billy Boyle. “Equally important is having a test that's non-invasive, cost effective and can be deployed in a primary care setting.”
The standard tool for detection is a biopsy. It is invasive and expensive, making it impractical to use for people who aren't yet symptomatic. Meanwhile, blood tests are less invasive, but they can be inaccurate and can’t discriminate between different stages of the disease.
In the past, breath tests have not been widely used because of the difficulties of reliably collecting and storing breath. But Owlstone’s technology could help change that.
The team is testing patients in the early stages of advanced liver disease, or cirrhosis, to identify and detect these biomarkers. In an initial study, Owlstone’s breathalyzer was able to pick out patients who had early cirrhosis with 83 percent sensitivity.
Boyle’s work is personally motivated. His wife died of colorectal cancer after she was diagnosed with a progressed form of the disease. “That was a big impetus for me to see if this technology could work in early detection,” he says. “As a company, Owlstone is interested in early detection across a range of diseases because we think that's a way to save lives and a way to save costs.”
How it works
In the past, breath tests have not been widely used because of the difficulties of reliably collecting and storing breath. But Owlstone’s technology could help change that.
Study participants breathe into a mouthpiece attached to a breath sampler developed by Owlstone. It has cartridges are designed and optimized to collect gases. The sampler specifically targets VOCs, extracting them from atmospheric gases in breath, to ensure that even low levels of these compounds are captured.
The sampler can store compounds stably before they are assessed through a method called mass spectrometry, in which compounds are converted into charged atoms, before electromagnetic fields filter and identify even the tiniest amounts of charged atoms according to their weight and charge.
The top four compounds in our breath
In an initial study, Owlstone captured VOCs in breath to see which ones could help them tell the difference between people with and without liver disease. They tested the breath of 46 patients with liver disease - most of them in the earlier stages of cirrhosis - and 42 healthy people. Using this data, they were able to create a diagnostic model. Individually, compounds like 2-Pentanone and limonene performed well as markers for liver disease. Owlstone achieved even better performance by examining the levels of the top four compounds together, distinguishing between liver disease cases and controls with 95 percent accuracy.
“It was a good proof of principle since it looks like there are breath biomarkers that can discriminate between diseases,” Boyle says. “That was a bit of a stepping stone for us to say, taking those identified, let’s try and dose with specific concentrations of probes. It's part of building the evidence and steering the clinical trials to get to liver disease sensitivity.”
Sabine Szunerits, a professor of chemistry in Institute of Electronics at the University of Lille, sees the potential of Owlstone’s technology.
“Breath analysis is showing real promise as a clinical diagnostic tool,” says Szunerits, who has no ties with the company. “Owlstone Medical’s technology is extremely effective in collecting small volatile organic biomarkers in the breath. In combination with pattern recognition it can give an answer on liver disease severity. I see it as a very promising way to give patients novel chances to be cured.”
Improving the breath sampling process
Challenges remain. With more than one thousand VOCs found in the breath, it can be difficult to identify markers for liver disease that are consistent across many patients.
Julian Gardner is a professor of electrical engineering at Warwick University who researches electronic sensing devices. “Everyone’s breath has different levels of VOCs and different ones according to gender, diet, age etc,” Gardner says. “It is indeed very challenging to selectively detect the biomarkers in the breath for liver disease.”
So Owlstone is putting chemicals in the body that they know interact differently with patients with liver disease, and then using the breath sampler to measure these specific VOCs. The chemicals they administer are called Exogenous Volatile Organic Compound) probes, or EVOCs.
Most recently, they used limonene as an EVOC probe, testing 29 patients with early cirrhosis and 29 controls. They gave the limonene to subjects at specific doses to measure how its concentrations change in breath. The aim was to try and see what was happening in their livers.
“They are proposing to use drugs to enhance the signal as they are concerned about the sensitivity and selectivity of their method,” Gardner says. “The approach of EVOC probes is probably necessary as you can then eliminate the person-to-person variation that will be considerable in the soup of VOCs in our breath.”
Through these probes, Owlstone could identify patients with liver disease with 83 percent sensitivity. By targeting what they knew was a disease mechanism, they were able to amplify the signal. The company is starting a larger clinical trial, and the plan is to eventually use a panel of EVOC probes to make sure they can see diverging VOCs more clearly.
“I think the approach of using probes to amplify the VOC signal will ultimately increase the specificity of any VOC breath tests, and improve their practical usability,” says Roger Yazbek, who leads the South Australian Breath Analysis Research (SABAR) laboratory in Flinders University. “Whilst the findings are interesting, it still is only a small cohort of patients in one location.”
The future of breath diagnosis
Owlstone wants to partner with pharmaceutical companies looking to learn if their drugs have an effect on liver disease. They’ve also developed a microchip, a miniaturized version of mass spectrometry instruments, that can be used with the breathalyzer. It is less sensitive but will enable faster detection.
Boyle says the company's mission is for their tests to save 100,000 lives. "There are lots of risks and lots of challenges. I think there's an opportunity to really establish breath as a new diagnostic class.”
Dec. 17th Event: The Latest on Omicron, Boosters, and Immunity
The Omicron variant poses new uncertainty for the vaccines, which four leading experts will address during our virtual event on December 17th, 2021.
This virtual event will convene leading scientific and medical experts to discuss the most pressing questions around the new Omicron variant, including what we know so far about its ability to evade COVID-19 vaccines, the role of boosters in eliciting heightened immunity, and the science behind variants and vaccines. A public Q&A will follow the expert discussion.
EVENT INFORMATION:
Date: Friday Dec 17, 2021
2:00pm - 3:30pm EST
Dr. Céline Gounder, MD, ScM, is the CEO/President/Founder of Just Human Productions, a non-profit multimedia organization. She is also the host and producer of American Diagnosis, a podcast on health and social justice, and Epidemic, a podcast about infectious disease epidemics and pandemics. She served on the Biden-Harris Transition COVID-19 Advisory Board.
Dr. Theodora Hatziioannou, Ph.D., is a Research Associate Professor in the Laboratory of Retrovirology at The Rockefeller University. Her research includes identifying plasma samples from recovered COVID-19 patients that contain antibodies capable of neutralizing the SARS-CoV-2 coronavirus.
Dr. Onyema Ogbuagu, MBBCh, is an Associate Professor at Yale School of Medicine and an infectious disease specialist who treats COVID-19 patients and leads Yale’s clinical studies around COVID-19. He ran Yale’s trial of the Pfizer/BioNTech vaccine.
Dr. Eric Topol, M.D., is a cardiologist, scientist, professor of molecular medicine, and the director and founder of Scripps Research Translational Institute. He has led clinical trials in over 40 countries with over 200,000 patients and pioneered the development of many routinely used medications.
This event is the fourth of a four-part series co-hosted by Leaps.org, the Aspen Institute Science & Society Program, and the Sabin–Aspen Vaccine Science & Policy Group, with generous support from the Gordon and Betty Moore Foundation and the Howard Hughes Medical Institute.
Kira Peikoff was the editor-in-chief of Leaps.org from 2017 to 2021. As a journalist, her work has appeared in The New York Times, Newsweek, Nautilus, Popular Mechanics, The New York Academy of Sciences, and other outlets. She is also the author of four suspense novels that explore controversial issues arising from scientific innovation: Living Proof, No Time to Die, Die Again Tomorrow, and Mother Knows Best. Peikoff holds a B.A. in Journalism from New York University and an M.S. in Bioethics from Columbia University. She lives in New Jersey with her husband and two young sons. Follow her on Twitter @KiraPeikoff.
7 Things to Know about the U.S.’s Capability to Detect Omicron
A visualization of the original coronavirus causing COVID-19, which has now been detected across the globe in a highly mutated form called Omicron.
If the new variant Omicron isn’t here already – which many experts suspect that it is – it will be soon. While we wait for scientists to conduct the necessary research to characterize its transmissibility, potential fitness at immune evasion, and disease severity, we wanted to give Leaps.org readers a window into how the U.S. is positioned to detect the variant. So we spoke to Kelly Wroblewski, director of infectious diseases at the Association of Public Health Laboratories, a membership organization that represents state and local government health labs in the United States. Here are seven insights she shared.
1) If you test positive for COVID-19 with a standard PCR test, the diagnostic report will not tell you which variant you have. There are no diagnostic tests available for your doctor to order to identify variants. To find out the variant, the specimen must be sent to a commercial, clinical, academic, or public health laboratory for genetic sequencing.
2) Today, the U.S. sequences about 5 to 10 percent of all diagnostic specimens that test positive for SARS-CoV-2 in order to determine which variants are circulating and where. Last week nationally, for example, labs sequenced about 80,000 samples. This represents a massive increase from last year at this time, when labs were only sequencing about 8,000 specimens per week. Currently, 99.5 percent of circulating SARS-CoV-2 virus in the U.S. is the Delta variant.
3) The U.S. is “very well prepared” to detect Omicron, Wroblewski says, “particularly compared to where we were when the Alpha variant, or B117 first emerged.” Of the hunt for Omicron, she adds, “it’s very reminiscent of that time, except we are doing so much more sequencing and we have so much better coverage with our sequencing geographically, and we're doing it in a much more timely way. We have the ability to find emerging variants that are circulating in 0.01 percent of the population.”
4) Deciding which specimens to sample is not totally random. Samples that have more virus are likely to lead to better sequencing results. Labs also look to have a diverse set of representative samples, meaning across geographic regions and across gender, race, ethnicity, and age groups. Clinical diversity is also important, such as including pregnant women, severe in-patient cases, mild cases, etc.
5) Sequencing more is not necessarily better to find Omicron faster. “We will increase the number of sequences to a certain extent,” Wroblewski says. “Where we exhibit some caution is doing that indiscriminately isn’t the most effective use of time and resources. The important thing is to try to find Omicron, and if you increase your testing capacity too much, right now, it's still predominantly Delta in the U.S. by a long shot. So you’re mostly going to sequence Delta and you run the risk of delaying your discovery of Omicron, if you focus solely on increasing sequencing.”
So besides just ramping up the sheer numbers of sequencing, diagnostic labs across the country are now advised to preferentially use a certain PCR test made by Thermo Fisher that can help hasten the detection of Omicron. It turns out that Omicron’s specific mutations in the Spike protein mean that the Spike is not picked up on this PCR test, which yields a type of result called an S-gene target failure. Yet the test will still accurately pick up a COVID-19 diagnosis, because it detects two other gene targets on Omicron that are not mutated. “That S-gene target failure gives you a good indication that you may have Omicron. It’s a good early screen.”
Labs will then still need to sequence the whole genome to confirm it matches the Omicron sequence. “So right now, the new recommendation is to use [the Thermo Fisher test] as much as possible to give us a better chance of detecting Omicron more quickly.”
6) This Thermo Fisher test is “fairly widely used” in the U.S. already, so many labs are already well positioned to make the shift. “In early to mid 2020,” Wroblewski explains, “when the supply chain issue for testing was acute, many public health labs implemented five, six, seven, eight different tests, just so they could get enough supplies to do all the testing. Now that we're in a much better place supply-chain wise, it's very difficult and time consuming and cumbersome to maintain all those different test methods all the time, and many, many labs scaled back to only one or two. And so this [new recommendation] would just be shifting to two for some labs that will be shifting to them.”
7) Once Omicron is found here, labs will be focused on finding as many cases as possible, and the CDC will be conducting a variety of studies to determine the impact of the variant on diagnostics, therapeutics, and vaccines. Epidemiologists at the local, state, and federal level will analyze which populations it is spreading in, as well as the severity of the disease it causes. They will work to sort out different impacts on vaccinated vs. unvaccinated populations. The ultimate goal, Wroblewski concludes, is to “use all of that information to make better public health decisions and inform the public about what’s going on.”
Kira Peikoff was the editor-in-chief of Leaps.org from 2017 to 2021. As a journalist, her work has appeared in The New York Times, Newsweek, Nautilus, Popular Mechanics, The New York Academy of Sciences, and other outlets. She is also the author of four suspense novels that explore controversial issues arising from scientific innovation: Living Proof, No Time to Die, Die Again Tomorrow, and Mother Knows Best. Peikoff holds a B.A. in Journalism from New York University and an M.S. in Bioethics from Columbia University. She lives in New Jersey with her husband and two young sons. Follow her on Twitter @KiraPeikoff.