(This is an excerpt of the Health Rounds newsletter, where we present latest medical studies on Tuesdays and Thursdays)
By Nancy Lapid
July 17 (Reuters) – We also report on an investigational vaccine that kept pancreatic cancer from developing in a small study of people at high genetic risk.
HIGHER LEVELS OF PLASTIC IN BLOOD LINKED WITH HEART ATTACKS
Heart attack survivors have higher levels of tiny plastic particles in their blood compared to cardiac patients who’ve never had heart attacks and people with normal blood vessels supplying the heart, a small study from Italy suggests.
Researchers say the study of 61 patients adds to growing evidence that environmental pollution may affect cardiovascular health.
Micro- and nano-plastics were detected in 84% of heart attack survivors, 40% of patients with chronic ischemic heart disease and 32% of patients with normal coronary arteries, according to a report in the European Heart Journal.
Heart attack patients had a greater variety of plastic types in their blood. The most common type was polyethylene, which is commonly used in packaging and consumer products.
The researchers also collected data on whether the patients were smokers and their exposure to pollution over the preceding two years. Patients exposed to higher long-term levels of air pollution were more likely to have microplastics in their blood, and smokers were six times more likely to have microplastics in their blood.
In addition, smokers exposed to higher air pollution levels all had plastics in their blood, compared with only 12.5% of patients who did not smoke and were not exposed to higher levels of air pollution.
“These findings do not prove that microplastics cause heart attacks, but they reveal a strong association between environmental exposures, microplastics in the blood and cardiovascular disease,” study leader Professor Emanuele Barbato from Sapienza University of Rome and Sant’Andrea University Hospital said in a statement.
An accompanying editorial notes that while the cardiovascular effects of plastic exposure were largely speculative until recently, emerging clinical evidence shows that plastic particles can enter the circulation and accumulate in vascular tissues, while lab experiments indicate that they trigger key mechanisms of vascular injury.
“Although substantial uncertainties remain, the convergence of epidemiological, clinical, and mechanistic evidence suggests that plastic pollution may represent a previously underestimated cardiovascular risk factor,” the editorial concludes.
PANCREATIC CANCER VACCINE PROMISING IN EARLY-STAGE TRIAL
An experimental vaccine targeting one of the most common genetic drivers of pancreatic cancer has kept the cancer from developing in high-risk patients in a pilot trial, researchers say.
The study is believed to be the first-in-human demonstration that a vaccine targeting the KRAS mutation can safely generate lasting immune responses, they reported in Cancer Discovery.
KRAS mutations are present in most pancreatic cancers and precancerous lesions. The vaccine, mKRAS-VAX, being developed by researchers at John Hopkins University, causes the immune system to recognize and destroy cells carrying any of six such mutations before they can develop into cancer.
Twenty participants at high genetic risk for pancreatic cancer and a pancreatic abnormality identified through imaging received four doses of the vaccine administered over 13 weeks.
In 18 participants, or 90%, the vaccine successfully activated immune cells capable of recognizing and remembering KRAS mutations. These immune cells remained detectable for as long as two years after vaccination.
At a median follow-up of 16.5 months, none of the participants had developed pancreatic cancer or a high-risk pancreatic lesion requiring surgical removal.
The vaccine was found to be safe, with only mild to moderate adverse effects – most often injection-site reactions, fatigue, chills and flu-like symptoms.
The investigators note that the study was designed primarily to evaluate safety and immune responses and does not prove the vaccine prevents pancreatic cancer.
“This is just the beginning, but the findings suggest that the immune system is getting activated,” study leader Dr. Elizabeth Jaffee of the John Hopkins Kimmel Cancer Center in Baltimore said in a statement.
“We have more work to do, but this is a good start aimed at prevention, which no one had thought about doing before.”
The KRAS vaccine was first tested in 2020 in patients who had undergone surgery and were at high risk of cancer recurrence. That study found that when the vaccine generated a strong immune response, patients remained disease-free for at least five years. The success of the 2020 testing prompted this prevention vaccine study.
The researchers have launched an additional study to test the vaccine in patients with high-risk pancreatic cysts undergoing surgical resection. This new study will enable them to see how vaccine-induced immune cells directly affect precancerous pancreatic tissue.
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(Reporting by Nancy Lapid; Editing by Nia Williams)
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