Scientists suspect that the plastics can be linked to a host of medical conditions, but clear evidence is elusive without appropriate biomarkers for clinical laboratory testing
Recent research indicates that microplastics and nanoplastics (MNPs) are accumulating in human organs at an increasing rate. The health impact is not entirely clear, but the research suggests that clinical laboratories could someday find themselves testing for levels of MNPs in patients.
In one study, scientists at the University of New Mexico and Oklahoma State University analyzed autopsy samples of liver, kidney, and frontal cortex brain tissue collected in 2016 and 2024. “Brains exhibited higher concentrations of MNPs than liver or kidney samples,” they wrote. However, “all organs exhibited significant increases from 2016 to 2024.”
“The concentrations we saw in the brain tissue of normal individuals, who had an average age of around 45 or 50 years old, were 4,800 micrograms per gram, or 0.5% by weight,” lead author Matthew Campen, PhD, Regents’ Professor, Pharmaceutical Sciences, University of New Mexico, and Director of the New Mexico Center for Metals in Biology and Medicine (CMBM), told CNN. “Compared to autopsy brain samples from 2016, that’s about 50% higher.”
Researchers have not yet uncovered clear evidence of specific health risks, but “what scientists worry about is several trends in disease prevalence that have been unexplained—Alzheimer’s disease and dementia, colorectal cancer in people under 50, inflammatory bowel disease, and global reductions in sperm count,” Campen told Everyday Health.
In another recent study, a different team of researchers at the University of New Mexico found high levels of microplastics in human and canine testicular tissue.
“At the beginning, I doubted whether microplastics could penetrate the reproductive system,” said lead author Xiaozhong Yu, MD, PhD, Professor, University of New Mexico College of Nursing in a university news story. “When I first received the results for dogs I was surprised. I was even more surprised when I received the results for humans.”
“The rate of increase in microplastics in the environment is exponential and we have every reason to believe that the concentrations in our bodies will continue to increase in the coming years and decades,” Matthew Campen, PhD (above), of the University of New Mexico told Everyday Health. As studies continue to produce evidence that nanoplastics affect human health, testing companies may develop biomarkers for clinical laboratory tests that measure the amount of microplastics in different organ locations. (Photo copyright: University of New Mexico.)
Landrigan told CNN that most people are exposed to MNPs through their diet, “but inhalation is also an important route.”
However, he added, “it’s important not to scare the hell out of people, because the science in this space is still evolving, and nobody in the year 2024 is going to live without plastic.”
CNN noted that experts consider nanoplastics to be the biggest concern [as opposed to microplastics] because they can infiltrate human cells.
“Somehow these nanoplastics hijack their way through the body and get to the brain, crossing the blood-brain barrier,” Campen told CNN. “Plastics love fats, or lipids, so one theory is that plastics are hijacking their way with the fats we eat which are then delivered to the organs that really like lipids—the brain is top among those.”
The US Food and Drug Administration (FDA) states that microplastics typically measure less than 5mm, whereas nanoplastics are less than a micron (micrometer). However, the agency notes that “there are currently no standard definitions for the size of microplastics or nanoplastics.”
What Are the Health Risks?
Scientists suspect that MNPs could be associated with cancer, cardiovascular disease, kidney disease, Alzheimer’s disease, and infertility, The Washington Post reported, but that they “still don’t have a clear sense of what these materials are doing to the human body.”
“In a 2021 study, researchers in Switzerland identified more than 10,000 chemicals used in the manufacture of plastic—of which over 2,400 were potentially ‘of concern’ for human health,” The Post noted.
“To be able to say we have a health impact, we need to have a direct correlation between a product and a health outcome,” Phoebe Stapleton, PhD, Associate Professor at the Rutgers University Ernest Mario School of Pharmacy (EMSOP), told The Post. “It’s very narrow, that straight line. And there’s so many different health outcomes there could be, and we’re finding these particles in so many different tissues.”
One study published in the New England Journal of Medicine (NEJM) suggested that MNPs in arteries could be risk factors for heart attacks or strokes. But even here, the authors wrote, “direct evidence that this risk extends to humans is lacking.”
Yu suspects that MNPs could be a factor in a global decline in sperm count, along with other environmental contaminants such as heavy metals and pesticides. His study found that polyethylene was the most prevalent plastic in dogs, followed by polyvinyl chloride (PVC). Higher levels of PVC correlated with lower sperm count, but there was no correlation with polyethylene.
“PVC can release a lot of chemicals that interfere with spermatogenesis, and it contains chemicals that cause endocrine disruption,” he said in the UNM news story.
Clinical laboratory managers should recognize that interest in identifying micro- and nanoplastics in every organ of the human body will increase. At some point, physicians may want labs to test their patients for microplastic levels in certain organ sites. This will likely be when enough published studies show a correlation between high levels of microplastics in certain locations of the body and specific disease states.
As demand for SARS-CoV-2 coronavirus testing increases, leaders of the College of American Pathologists meet online to brainstorm possible solutions to the crisis
In September, the College of American Pathologists (CAP) began its series of “virtual media briefings” given by leading pathologists and physicians at the forefront of COVID-19 testing which are designed to “offer insights and straight talk” on the crisis confronting today’s clinical laboratories.
During the third virtual meeting on December 9, presenters discussed how the ever-increasing demand for COVID-19 testing has placed an enormous amount of stress on clinical laboratories, medical technologists (MTs), and clinical laboratory scientists (CLSs) responsible for processing the high volume of SARS-CoV-2 tests, and on the supply chains medical laboratories depend on to receive and maintain adequate supplies of testing materials.
“As soon as we get one set of supplies, then it’s another set of supplies that we can’t get our hands on,” said Christine Wojewoda, MD, Clinical Pathologist and Associate Professor at the University of Vermont Medical Center, during the third CAP virtual briefing. “Right now, we’re very concerned that our lab can’t get pipette tips that have a certain filter in them to transfer patient samples into the tubes that we need, or the plates that we need to do the testing. If we can’t get the patient sample into where it needs to go, safely, without contaminating other patient samples, that’s a big issue.”
Other members of the CAP panel concurred with Wojewoda and indicated that their clinical labs also are encountering supply chain challenges.
“It’s a daily battle,” said Amy Karger, MD, PhD, Clinical Pathologist and Associate Professor at University of Minnesota Physicians. “One of our managers spends hours a day making sure our lab has enough supplies, plastics, and chemicals to do the testing that we want to do. And he is often having to look for alternative solutions for COVID-19 testing, making phone calls, trying to find alternative products, and so we have a consistent worry about that.”
A June survey of CAP-accredited laboratories for COVID-19 testing found that more than 60% of lab directors reported difficulties in procuring critical supplies needed to conduct COVID-19 testing. The respondents indicated they encountered substantial barriers to obtaining equipment needed for SARS-CoV-2 testing—particularly test kits (69%), swabs (66%), and transport media (62%).
Staff Burnout and Shortages at Many Medical Laboratories
Karger also indicated that she is concerned about staff burnout and the toll the workload is taking on medical technologists at her laboratory.
“Lab staff have been working full throttle since March. I think that is often lost on people. They kind of assumed that when cases were low with COVID-19, that maybe the lab staff got a break. Well, that wasn’t the case,” she stated, adding, “They [the medical technologists] were planning for this surge that we’re experiencing now and have been working often seven days a week, double shifts to get us to this point of high testing capacity [to respond to the demand for COVID-19 testing].”
Another member of the CAP panel echoed Karger’s concerns.
“We worry about that as well,” said Patrick Godbey, MD, Founder and Laboratory Director at Southeastern Pathology Associates and current CAP President. “This demand for COVID-19 testing has made an already bad situation worse because there’s an absolute shortage of medical laboratory personnel and the increased demands on clinical labs have made this shortage even more acute.”
Almost all of the surveyed CAP-accredited laboratories reported losses in revenue and financial stress since the pandemic started. But few had applied for any of the available funds offered through federal assistance programs. The survey found that the top issues among pathologists reported by laboratory directors were:
reduced work hours (72%),
reductions in pay (41%),
increased burnout (21%), and
increased work hours (20%).
According to the survey, the top stresses affecting non-pathologist professionals working in clinical labs were:
The diminishing labor pool trained for COVID-19 testing—coupled with high stress/burnout among existing staff—is a major impediment to ongoing expansion in the daily number of molecular COVID-19 tests that can be performed by the nation’s labs.
Also, the already-tight supply of med techs means many metropolitan area labs—particularly hospital labs—are operating with just 75% of the number of staff they are authorized to hire, because there are no techs available. Thus, existing staff are working lots of overtime, and vacant FTE positions are being temporarily filled by MTs placed by employment agencies.
A New York Times (NYT) article in December, titled, “‘Nobody Sees Us’: Testing-Lab Workers Strain Under Demand,” revealed that testing teams across the country are dealing with “burnout, repetitive-stress injuries, and an overwhelming sense of doom.” The article reported on the shortages of supplies needed to perform testing and states there is a “dearth of human power” in the field of pathology as well.
The supply of MTs and CLSs, molecular PhDs, clinical pathologists, MLTs, and other laboratory scientists available to work in the nation’s labs is finite and training programs take years to produce qualified workers to perform laboratory testing.
In the NYT article, microbiologist Karissa Culbreath, PhD (above), Scientific Director, Infectious Diseases at TriCore Reference Laboratories, and Assistant Professor of Pathology at the University of New Mexico, said that when shortages arise, “there are workarounds for almost everything else, but people are irreplaceable.” In addition to the large volume of COVID-19 tests that labs are expected to perform, they also must keep up with the other tests that are sent to them for analysis. Some facilities are even transitioning to 24/7 testing to keep up with the demand. “Labs are trying to maintain our standard of operation with everything else, with a pandemic on top of it,” said Culbreath. (Photo copyright: KOB 4/NBC.)
Should Clinical Lab Workers Be First to Receive the COVID-19 Vaccine?
In the third CAP virtual media briefing, the panel suggested that medical laboratory workers should be among the first to receive the COVID-19 vaccine.
“They are encountering and handling thousands of samples that have active live virus in them,” Karger said. “We are getting 10,000 samples a day [for SARS-CoV-2 testing]. That’s a lot of handling of infectious specimens and we do want them to be prioritized for vaccination.”
She added, “From an operational standpoint, we need to keep our lab up and running. We don’t want to have staff out such that we would have to decrease our SARS-CoV-2 testing capacity, which would have widespread impact on our health system and our state.”
Since the pandemic began nearly a year ago, there have been more than 18 million cases of COVID-19 confirmed in the US and more than 300,000 people have died from the virus, according to data from the federal Centers for Disease Control and Prevention (CDC).
And, as we move into flu season, the number of new COVID-19 cases is reportedly increasing, which adds more stress to clinical laboratories and their supply chains. As this is unlikely to end anytime soon, clinical lab managers must find new ways to do more with less.
Clinical laboratory professionals and pathologists are part of multi-disciplinary efforts to curb healthcare-associated infections
One interesting fact about a national list of hospitals that rank highest in infection prevention is that they are mostly smaller and non-teaching hospitals. This was one finding from a recent survey conducted by Consumer Reports.
