A filter used to remove excess fats from the blood of people with cardiovascular disease may also trap much smaller "stowaways": some persistent synthetic chemicals and microplastics.
A procedure known as therapeutic apheresis involves passing a patient's blood through a special machine that filters out target substances and then returns the blood to the body.
This drug was not designed to remove pollutants from the environment. It is typically used in severe cases where medication alone is insufficient to effectively remove cholesterol—the fat-carrying particles associated with the risk of cardiovascular disease.
However, when researchers in Germany compared blood samples taken immediately before and after the procedure, levels of some synthetic chemicals decreased.
Preliminary results show that the filters may also trap certain microplastic particles.
In a study devoted to brain health, The study focused on per- and polyfluoroalkyl substances, or PFAS, which are used in many products such as non-stick coatings, waterproof fabrics, and some types of food packaging.
Because some PFAS persist in the environment and human bodies for years, they are often referred to as "forever chemicals.".
Human exposure to PFAS can occur in a variety of ways, including through contaminated water and food, consumer products, packaging, and even household dust.
«"We believe the most important finding of our study is that therapeutic apheresis, a procedure originally developed to remove lipoproteins from the blood of patients with severe cardiovascular disease, also reduces circulating levels of PFAS and microplastics," molecular endocrinologist Charlotte Stenblock of the Technical University of Dresden told ScienceAlert.
«"This was unexpected because PFAS and microplastics are chemically different from lipoproteins and were not the intended targets for treatment.".
Long-term exposure to some PFAS has been linked to increased total and LDL ("bad") cholesterol levels, changes in the immune and hormonal systems, and certain cancers, although the risk depends on the type, dose, and duration of exposure.
«"Good HDL cholesterol" and "bad LDL cholesterol." (University of Utah)
Researchers examined data from 14 patients who underwent double-filtration plasmapheresis. Blood cells are separated from the plasma, which then passes through a second filter that traps larger particles, such as lipoproteins.
Before and after each of the two double filtration procedures, the patients' blood levels of four common PFAS were measured. Immediately after one of the procedures, their blood levels decreased by 25 percent.
Another lab, analyzing samples from four patients using a different method, found average reductions in concentrations of five PFAS of 43.5 to 75.8 percent.
However, the small sample size and the use of different methods preclude a direct comparison of the two sets of results. Higher percentages also do not mean that more than half of these specific PFAS molecules were removed in each patient.
Some PFAS bind to blood proteins and can travel along with lipoproteins, so they may be retained by filters directly or removed along with target substances.
«"Our current hypothesis is that these environmental contaminants are trapped directly within the apheresis filters or form aggregates or complexes with lipoproteins and plasma proteins, allowing them to be removed simultaneously with the procedure," says Steenblock.
Schematic overview of how therapeutic apheresis can reduce circulating PFAS and BNP concentrations. (Bornstein et al., Brain health , 2026)
The results of the microplastics study were less consistent.
In four patients, polyethylene levels decreased in all, and polyvinyl chloride levels in three. However, other polymers did not follow the same pattern, and levels of some circulating plastics increased after treatment.
These discrepancies may be related to measurement methods, environmental contamination, or plastic components of the apheresis system. Therefore, the study does not prove that apheresis reliably reduces microplastic levels in human blood.
Steenblock says the team has repeatedly found microplastics in material washed off used filters.
«"We are very confident that apheresis does not simply redistribute microplastic particles, but actually removes them from the circulation, as we have repeatedly detected microplastics in the eluates obtained from apheresis filters after processing," she says.
However, particles captured by the filter do not necessarily indicate a reduction in the overall amount of microplastics in the body. Blood tests only show what is currently circulating; particles accumulated in tissues can subsequently reenter the bloodstream.
This is important because microplastics have been found in human brain, liver and kidney tissue, but their long-term health effects remain unclear.
The pilot study involved small, partially differentiated patient groups, and microplastic measurements are subject to environmental pollution. The researchers did not determine how long the reduction in microplastic levels lasted or whether the patients' health improved.
Therefore, larger controlled studies, standardized measurements, and a longer follow-up period are needed before apheresis can be considered as a treatment option for environmental pollutant exposure.
In a separate 2026 study published in Journal of Clinical Apheresis, A total of 174 plasmapheresis procedures were studied in 114 patients. Microplastic levels decreased in patients with high baseline levels but increased in patients with low levels.
The authors of this article suggest that plastic tubes and bags containing liquid used during the procedure may have released particles into the blood.
See also: «'Forever chemicals' found in 98.8% of human blood samples tested
Currently, available data does not support the effectiveness of apheresis as a microplastic "detoxification" method. It is a medical procedure used for certain conditions and performed under the supervision of a specialist.
However, the findings raise an intriguing possibility: a filter designed to capture harmful particles containing fats may also remove some PFAS and the microplastics that travel with them.
The results of the study were published in the journal Brain Health .
ScienceAlert articles are written, fact-checked, and edited by humans; they are never generated by artificial intelligence. Don't miss a single article; subscribe here.
Related news
-
Research shows that just one workout can significantly improve sleep.
-
Regular sugar appears to promote cancer cell release and spread.
-
Brain scans have shown that patients with long-term COVID-19 have fewer dopamine-producing nerve endings in 18%.