Proteins in human saliva make up its proteome and may be the key to new, precision medicine diagnostics that would give clinical pathologists new capabilities to identify disease
Clinical pathologists may soon have an array of new precision medicine diagnostic tools based on peoples’ saliva. There are an increasing number of “–omes” that can be the source of useful diagnostic biomarkers for developing clinical laboratory tests. The latest is the world’s first saliva protein biome wiki.
Called the Human Salivary Proteome Wiki (HSP Wiki), the “public data platform,” which was created by researchers at the University of Buffalo, is the “first of its kind,” according to Labroots, and “contains data on the many thousands of proteins present in saliva.”
The HSP Wiki brings together data from independent studies on proteins present in human saliva. One of the researchers’ goals is to speed up the development of saliva-based diagnostics and personalized medicine tools.
In “The Human Salivary Proteome Wiki: A Community-Driven Research Platform,” published in the Journal of Dental Research, the researchers wrote, “Saliva has become an attractive body fluid for on-site, remote, and real-time monitoring of oral and systemic health. At the same time, the scientific community needs a saliva-centered information platform that keeps pace with the rapid accumulation of new data and knowledge by annotating, refining, and updating the salivary proteome catalog.
“We developed the Human Salivary Proteome (HSP) Wiki as a public data platform for researching and retrieving custom-curated data and knowledge on the saliva proteome. … The HSP Wiki will pave the way for harnessing the full potential of the salivary proteome for diagnosis, risk prediction, therapy of oral and systemic diseases, and preparedness for emerging infectious diseases,” they concluded.
“This community-based data and knowledge base will pave the way to harness the full potential of the salivary proteome for diagnosis, risk prediction, and therapy for oral and systemic diseases, and increase preparedness for future emerging diseases and pandemics,” Stefan Ruhl, DDS, PhD (above right, with Omer Gokcumen, PhD, Associate Professor of Biological Sciences on left), Professor, Department of Oral Biology, University of Buffalo, and lead researcher of the study, told Labroots. Development of precision medicine clinical laboratory diagnostics is part of their research goals. (Photo copyright: University of Buffalo.)
Where Does Saliva Come From?
Saliva is a complex biological fluid that has long been linked to oral health and the health of the upper gastrointestinal tract. Only recently, though, have scientists begun to understand from where in the body saliva proteins originate.
The authors wrote: “Salivary proteins are essential for maintaining health in the oral cavity and proximal digestive tract, and they serve as potential diagnostic markers for monitoring human health and disease. However, their precise organ origins remain unclear.
“Through transcriptomic analysis of major adult and fetal salivary glands and integration with the saliva proteome, the blood plasma proteome, and transcriptomes of 28+ organs, we link human saliva proteins to their source, identify salivary-gland-specific genes, and uncover fetal- and adult-specific gene repertoires,” they added.
“Our results pave the way for future investigations into glandular biology and pathology, as well as saliva’s use as a diagnostic fluid,” the researchers concluded.
Saliva plays a crucial role in digestion by breaking down starches. It also provides a protective barrier in the mouth. When salivary glands malfunction, patients can face serious health consequences. Although clinicians and scientists have long understood the importance of saliva to good health, the question now is whether it contains markers of specific diseases.
“The Human Salivary Proteome Wiki contains proteomic, genomic, transcriptomic data, as well as data on the glycome, sugar molecules present on salivary glycoproteins. New data goes through an interdisciplinary team of curators, which ensures that all input data is accurate and scientifically sound,” noted Labroots.
The graphic above “shows the interconnectedness of the thousands of salivary proteins originating from blood plasma, parotid glands, and submandibular and sublingual glands. The diagram is one of many tools available to researchers and clinicians through the Human Salivary Proteome Wiki,” noted a UBNow blog post. (Graphic copyright: University of Buffalo.)
Omics and Their Role in Clinical Laboratory Diagnostics
Proteomics is just one of several hotly-researched -omics that hold the potential to develop into important personalized medicine and diagnostics tools for pathologists. Genomics is a related area of research being studied for its potential to benefit precision medicine diagnostics.
However, unlike genomes, which do not change, proteomes change constantly. That is one of the main reasons studying the human salivary proteome could lead to valuable diagnostics tools.
Combining the study of the -omes with tools like mass spectrometry, a new era of pathology may be evolving. “With the rapid decrease in the costs of omics technologies over the past few years, whole-proteome profiling from tissue slides has become more accessible to diagnostic labs as a means of characterization of global protein expression patterns to evaluate the pathophysiology of diseases,” noted Pathology News.
Saliva and the Age of Precision Medicine
The study of the -omes may be an important element in the evolution of precision medicine, because of its ability to provide information about what is happening in patients’ bodies at the point of care.
Thus, a full understanding of the proteome of saliva and what causes it to change in response to different health conditions and diseases could open the door to an entirely new branch of diagnostics and laboratory medicine. It is easy and non-invasive to gather and, given that saliva contains so much information, it offers an avenue of study that may improve patients’ lives.
It also would bring us closer to the age of precision medicine where clinical laboratory scientists and pathologists can contribute even more value to referring physicians and their patients.
If tattoos can accurately be used in the diagnostic process, might clinical laboratories soon offer these types of diagnostic tattoos at their patient service centers?
Could color-changing tattoos help diagnose illnesses? Researchers at the ATLAS Institute at the University of Colorado Boulder think so. They are working on prototypes of permanent tattoos that can detect chemical changes in the body and smart tattoo ink that would take the concept of wearable medical devices to a whole new level.
Called “dynamic” or “smart” tattoos, these color-changing tattoos have a biomedical purpose. They alert individuals to potential health issues due to changes in the biochemistry in their body. The technology has already been used in animal studies to detect sodium, glucose, electrolytes, and pH levels. Pathologists and clinical lab manager will recognize the value of a relatively non-invasive way to measure and track changes in these types of biomarkers.
“We developed a photochromic tattoo that serves as an intradermal ultraviolet (UV) radiometer that provides naked-eye feedback about UV exposure in real time. These small tattoos, or ‘solar freckles’, comprise dermally implanted colorimetric UV sensors in the form of nano encapsulated leuco dyes that become more blue in color with increasing UV irradiance,” the ATLAS scientists wrote.
Studies analyzing the efficacy of dynamic tattoos have provided strong evidence that they can be engineered to change color and sense and convey medical information. This field is called “dynamic tattoos” and in recent years various proof-of-concept studies have demonstrated that tattoos can be used to “pick up changes in sodium, glucose, electrolytes or pH levels in animal models,” Labroots reported.
“We demonstrate the tattoos’ functionality for both quantitative and naked-eye UV sensing in porcine skin ex vivo, as well as in human skin in vivo. Solar freckles offer an alternative and complementary approach to self-monitoring UV exposure for the sake of skin cancer prevention,” the researchers explained in their ACS Nano article.
“Activated solar freckles provide a visual reminder to protect the skin, and their color disappears rapidly upon removal of UV exposure or application of topical sunscreen. The sensors are implanted in a minimally invasive procedure that lasts only a few seconds yet remain functional for months to years,” they added.
“These semipermanent tattoos provide an early proof-of-concept for long-term intradermal sensing nanomaterials that provide users with biomedically relevant information in the form of an observable color change,” the ATLAS researchers concluded.
“When you think about what a tattoo is, it’s just a bunch of particles that sit in your skin,” Carson Bruns, PhD, Assistant Professor, Laboratory for Emergent Nanomaterials, ATLAS Institute, Mechanical Engineering, told Technology.org. “Our thought is: What if we use nanotechnology to give these particles some function?”
The invisible tattoos Bruns and the ATLAS team created turn blue in the presence of harmful levels of ultraviolet radiation to inform wearers that their skin needs protection and to apply or reapply sunscreen.
“I have always been interested in both art and science. My favorite type of art is tattooing and my favorite type of science is nanotechnology,” Carson Bruns, PhD (above), Assistant Professor, Mechanical Engineering, ATLAS Institute, told Inked. “When I had an opportunity to start a new research program, I thought it would be really fun and interesting to try and put the two together.” Might innovative medical laboratories one day operate “tattoo parlors” in their patient service centers to provide patients with tattoos that monitor key biometrics? (Photo copyright: Inked.)
The tattoo ink used for these tattoos contains a UV-activated dye inside of a plastic nano capsule that is less than a thousandth of a millimeter in size, or several sizes smaller than the width of a human hair. The capsules protect the dyes from wear and tear while allowing them to sense and respond to biochemical changes in the body. These tattoos are implanted into the skin using tattoo machines, much like getting a regular tattoo.
“I call them solar freckles because they’re like invisible freckles that are powered by sunshine,” Bruns told Inked, adding, “Millions of cases of preventable skin cancer are treated every year. I hope that the UV-sensitive tattoo will help us reduce the number of those cases by reminding people when their skin is exposed to unsafe levels of UV light.”
Dynamic Tattoos May Help People Lead Healthier Lives
One downside to these tattoos is that they only last a few months before they begin to degrade, requiring the wearer to get a “booster” tattoo.
The researchers hope that someday similar tattoo technologies will be applied to a wide variety of preventative and diagnostic applications. The goal is to enable people to detect health issues and allow them to lead healthier lives.
“We want to make tattoos that will allow you to, for example, sense things that you can’t currently sense,” Bruns told Inked. “Sometimes I joke that we want to make tattoos that give you superpowers.”
The ATLAS scientists imagine a future where tattoos can detect things like blood alcohol levels or high/low blood sugar levels or other changes in a person’s biochemistry.
“More generally, I hope that smart tattoos will help people stay healthy and more informed about their body, while also giving people new ways to express themselves creatively,” Bruns said.
Using Dynamic Tattoo to Detect Cancer
In 2018, a team of biologists created a tattoo comprised of engineered skin cells and an implantable sensor which could detect elevated blood calcium levels that are present in many types of cancers. These cancer-detecting tattoos were tested on living mice and would darken to notify researchers of potential problems.
Scientists at the Department of Biosystems Science and Engineering at the Swiss Federal Institute of Technology Zurich (ETHZ), Switzerland, developed a biomedical tattoo that uses bio sensitive ink and changes color based on variations in the body’s interstitial fluid. It recognizes four widespread cancers:
breast,
colon,
lung, and
prostate.
“Nowadays, people generally go to the doctor only when the tumor begins to cause problems. Unfortunately, by that point it is often too late,” Martin Fussenegger, PhD, Professor of Biotechnology and Bioengineering at the Department of Biosystems Science and Engineering (D-BSSE) of the ETH Zurich in Basel as well as at the University of Basel, told Medical News Today.
“For example, if breast cancer is detected early, the chance of recovery is 98%,” he continued. “However, if the tumor is diagnosed too late, only one in four women has a good chance of recovery.”
Though it appears that dynamic tattoos may be a functional and decorative way to track health, rigorous research and safety testing on human subjects will be required before clinical laboratories can set up diagnostic tattoo parlors in their offices.
Nevertheless, this concept demonstrates how different technologies under development may provide clinical laboratories with innovative and unusual diagnostic tools in the future.
The new method employs a pH sensitive dye and AI algorithms to ‘distinguish between cells originating from normal and cancerous tissue, as well as among different types of cancer’ the researchers said
Might a pH-sensitive dye in tandem with an image analysis solution soon be used to identify cancerous cells within blood samples as well within tissue? Recent research indicates that could be a possibility. If further studies and clinical trials confirm this capability, then anatomic pathologists could gain another valuable tool to use in diagnosing cancers and other types of disease.
Currently, surgical pathologists use a variety of hematoxylin and eosin stains (H/E) to bring out useful features in cells and cell structures. So, staining tissue on glass slides is a common practice. Now, thanks to machine learning and artificial intelligence, anatomic pathologists may soon have a similar tool for spotting cancer cells within both tissue and blood samples.
Researchers at the National University of Singapore (NUS) have developed a method for identifying cancer that uses a pH sensitive dye called bromothymol blue. The dye reacts to various levels of acidity in cancer cells by turning colors. “The pH inside cancer cells tends to be higher than that of healthy cells. This phenomenon occurs at the very early phases of cancer development and becomes amplified as it progresses,” Labroots reported.
In “Machine Learning Based Approach to pH Imaging and Classification of Single Cancer Cells,” published in the journal APL Bioengineering, the NUS researchers wrote, “Here, we leverage a recently developed pH imaging modality and machine learning-based single-cell segmentation and classification to identify different cancer cell lines based on their characteristic intracellular pH. This simple method opens up the potential to perform rapid noninvasive identification of living cancer cells for early cancer diagnosis and further downstream analyses.”
According to an NUS news release, the bromothymol blue dye is “applied onto patients’ cells” being held ex vivo in cell culture dishes. The dye’s color changes depending on the acidity level of the cancer cells it encounters. Microscopic images of the now-visible cancers cells are taken, and a machine-learning algorithm analyzes the images before generating a report for the anatomic pathologist.
The NUS researchers claim the test can provide answers in about half an hour with 95% accuracy, Labroots reported.
“The ability to analyze single cells is one of the holy grails of health innovation for precision medicine or personalized therapy. Our proof-of-concept study demonstrates the potential of our technique to be used as a fast, inexpensive and accurate tool for cancer diagnosis,” said Lim Chwee Teck, PhD, NUS Society Professor and Director of NUS’ Institute for Health Innovation and Technology, in the NUS news release.
The novel technique for differentiating cancer cells from non-cancerous cells being developed at the National University of Singapore (NUS) could eventually become useful in detecting cancer cells in tissue samples, either obtained from tumor biopsies or blood samples. “As the number of cells in these samples can be in millions or even billions, the ability to detect the very few cancer cells among the others will be useful for clinicians,” NUS Society Professor and Director of NUS’ Institute for Health Innovation and Technology, Lim Chwee Teck, PhD (above) told The Straits Times. (Photo copyright: The Straits Times.)
AI Cell Analysis versus Laborious Medical Laboratory Steps
By developing an AI-driven method, Professor Lim and the NUS team sought to improve upon time-consuming techniques for identifying cells that traditionally involve using florescent probes, nanoparticles, and labeling steps, or for cells to be fixed or terminated.
“Unlike other cell analysis techniques, our approach uses simple, inexpensive equipment, and does not require lengthy preparation and sophisticated devices. Using AI, we are able to screen cells faster and accurately,” Professor Lim told Labroots. “Furthermore, we can monitor and analyze living cells without causing any toxicity to the cells or the need to kill them.”
The new technique may have implications for cancer detection in tumor tissue as well as in liquid biopsies.
“We are also exploring the possibility of performing the real-time analysis on circulating cancer cells suspended in blood,” Professor Lim said in the NUS news release. “One potential application for this would be in liquid biopsy where tumor cells that escaped from a primary tumor can be isolated in a minimally-invasive fashion from bodily fluids such as blood.”
Diagnosing Cancer in Real Time
The NUS’ method requires more research and clinical studies before it could become an actual tool for anatomic pathologists and other cancer diagnosticians. Additionally, the NUS researchers acknowledged that the focus on only four cell lines (normal cells, benign breast tumor cells, breast cancer cells, and pancreatic cancer cells) limited their study, as did lack of comparison with conventional florescent pH indicators.
Still, the NUS scientists are already planning more studies to advance their concept to different stages of cell malignancy. They envision a “real-time” version of the technique to enable recognition of cells and fast separation of those that need to be referred to clinical laboratories for molecular testing and/or genetic sequencing.
Medical laboratory leaders may want to follow the NUS study. An inexpensive AI-driven method that can accurately detect and classify cancer cells based on pH within the cells is provocative and may be eventually become integrated with other cancer diagnostics.
