The Microplastics Cancer Threat, By Mrs Vera West
I continue to report on the micro and nano plastic issue as there are new developments from ongoing research. A new study entitled, "Effects of Microplastic Exposure on Human Digestive, Reproductive, and Respiratory Health: A Rapid Systematic Review," published in the journal Environmental Science and Technology, examined the literature on the impacts of micro and nano plastics on human health. As noted in a previous blog article, much research in the field has used animal models, mainly rats. However, with the limited number of human studies to date, some conclusions were made: "that microplastics are "suspected" to harm human reproductive, digestive, and respiratory health, with a suggested link to colon and lung cancer. Future research on microplastics should investigate additional health outcomes impacted by microplastic exposure and identify strategies to reduce exposure."
As this is from a limited number of studies, with human research only just getting started, we can be sure that given that microplastics are now to be found all over the planet, that ill health effects will be a grave future concern. The problem will be how to put the genies, of plastic, back in their bottles now.
https://petermcculloughmd.substack.com/p/microplastics-linked-to-cancer-and
"Last week, the study titled Effects of Microplastic Exposure on Human Digestive, Reproductive, and Respiratory Health: A Rapid Systematic Review by Chartres et al was published in the journal Environmental Science and Technology:
Microplastics are ubiquitous environmental contaminants for which there are documented human exposures, but there is a paucity of research evaluating their impacts on human health. We conducted a rapid systematic review using the "Navigation Guide" systematic review method.
We searched four databases in July 2022 and April 2024 with no restriction on the date. We included studies using predefined eligibility criteria that quantitatively examined the association of microplastic exposure with any health outcomes. We amended the eligibility criteria after screening studies and prioritized digestive, reproductive, and respiratory outcomes for further evaluation.
We included three human observational studies examining reproductive (n= 2) and respiratory (n = 1) outcomes and 28 animal studies examining reproductive (n = 11), respiratory (n = 7), and digestive (n = 10) outcomes. For reproductive outcomes (sperm quality) and digestive outcomes (immunosuppresion) we rated overall body evidence as "high" quality and concluded microplastic exposure is "suspected" to adversely impact them. For reproductive outcomes (female follicles and reproductive hormones), digestive outcomes (gross or microanatomic colon/small intestine effects, alters cell proliferation and cell death, and chronic inflammation), and respiratory outcomes (pulmonary function, lung injury, chronic inflammation, and oxidative stress) we rated the overall body of evidence as "moderate" quality and concluded microplastic exposure is "suspected" to adversely impact them. We concluded that exposure to microplastics is "unclassifiable" for birth outcomes and gestational age in humans on the basis of the "low" and "very low" quality of the evidence.
We concluded that microplastics are "suspected" to harm human reproductive, digestive, and respiratory health, with a suggested link to colon and lung cancer. Future research on microplastics should investigate additional health outcomes impacted by microplastic exposure and identify strategies to reduce exposure."
"Research led by Zhejiang Agriculture and Forestry University in China has performed a metadata investigation into the presence of microplastics in humans. They report a concerning relationship between micro and nanoplastic (MNP) concentrations in damaged tissues and links with multiple health conditions.
Plastic usage soared from 1.5 million metric tons in the 1950s to nearly 390.7 million in 2021. With the increased use in consumer products came elevated microscopic plastic pollution circulating in soil and waterways, eventually accumulating in the environment, food webs and human tissues.
Consistent methods to pinpoint and quantify MNPs in human tissues are lacking. Reliable data linking MNPs to human diseases are necessary for assessing potential risks and developing mitigation measures.
In the study, "Mapping micro(nano)plastics in various organ systems: Their emerging links to human diseases?" published in TrAC Trends in Analytical Chemistry, investigators collected 61 available research articles for MNP detection in human tissues, plus 840 articles on MNP toxicological mechanisms.
Data came from spectroscopy, microscopy, and pyrolysis-gas chromatography/mass spectrometry investigations to identify polymer types in different tissues. Toxicological studies employed cell models and animal experiments to examine oxidative stress, inflammatory responses, and related signaling pathways.
The studies documented particles detected in skin, arteries, veins, thrombi, bone marrow, testes, semen, uterus, and placenta. MNPs were found in the digestive system, from saliva to feces, liver, and gallstones.
Within the respiratory system, MNPs were everywhere, including lung tissue, with microscopic fibers common in bronchoalveolar lavage fluid and sputum.
Positive correlations emerged between particle abundance and specific disorders, such as inflammatory bowel disease, thrombosis, cervical cancer, and uterine fibroids.
Toxicological tests showed possible MNP-triggered oxidative stress, mitochondrial dysfunction, inflammatory responses, and apoptosis in various cell types, along with organ-level concerns like neurodegenerative disease onset when crossing the blood-brain barrier.
A critically important signal in the metadata discovered by the researchers was that measured levels of MNPs tended to be higher in tissues with lesions than in non-lesioned tissues. These included inflamed intestines, fibrotic lungs, or cancerous growths, suggesting a potential link between MNP buildup and local pathology.
There is an intriguing "what came first, the chicken or the egg" problem with lesions having higher concentrations of MNPs.
A quick author note: The chicken or egg problem has an obvious solution, as eggs predate chickens by hundreds of millions of years. Refining the question to "what came first, the chicken or the chicken's egg" could infer that the first chicken emerged from the egg of a non-chicken fowl predecessor, but would require still further refinement as to whether "chicken's egg" belongs to the fowl, the chicken within, or requires a chicken to lay it."
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