Background and Rationale:
Microplastics and nanoplastics (MNPs) have been detected in human blood and every major organ. Increasingly, studies associate MNP exposure with a range of health conditions, including cardiovascular disease, metabolic disease, gastrointestinal disease, neurodegenerative disease, and cancer. There has been very little study of clinical approaches to remove MNPs from the human body. Such efforts have been limited in part by challenges in measuring MNPs in human blood, especially nanoplastics, which are too small to be detected by most equipment.
Double-filtration plasmapheresis (DFPP) is an established treatment for dozens of health conditions mediated by substances circulating in plasma. In DFPP, a first filter separates blood cells from plasma, and a second filter removes molecules from plasma according to the filter characteristics. The filtered plasma and blood cells are then recombined and returned to the patient. In 2025, a study showed that the material removed from plasma by a specialized type of DFPP called Inuspheresis with the CE-marked IN300 device includes microplastic molecules.
Study Design:
This is a single-group, open-label, prospective, within-subject observational pilot study. Approximately 20 adult participants who have already been independently prescribed DFPP by their treating clinic will be enrolled.
Procedures:
Each participant provides written informed consent, then undergoes blood sampling shortly before the DFPP treatment session and again within 10 minutes after the end of the treatment session, after approximately 0.75 plasma volumes have been treated. Adverse events and tolerability observations are recorded throughout the treatment encounter. For a randomly selected subset of five participants, additional exploratory analyses will be performed on paired blood samples using pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), and a sample of DFPP eluate will be collected to assess whether plastic polymers are present in the material removed during treatment.
Analytical Methods:
Primary: Nano-flow cytometry with Nile Red staining, which has been shown in multiple studies to provide detection and counting of microplastic and nanoplastic particles down to approximately 50 nanometers in human blood.
Exploratory: Py-GC-MS for polymer-specific mass quantification in blood and eluate in a five-participant subset.
Statistical Analysis:
The primary analysis will evaluate within-subject change in circulating MNP particle concentration using a paired pre/post design. The primary hypothesis test will be the Wilcoxon matched-pairs signed-rank test. Effect size will be summarized using the median within-participant percent change and geometric mean post/pre ratio with a 95% confidence interval. Based on an approximate paired-analysis power calculation, a sample size of 20 participants provides approximately 80% power to detect a large within-participant reduction on the order of 50%, assuming a two-sided alpha of 0.05 and variability of paired log post/pre ratios not materially exceeding approximately 1.0. Exploratory Py-GC-MS analyses in the five-participant subset are not powered for definitive hypothesis testing; results will be summarized using absolute and percent change. Quality-control procedures include procedural blank review; values at or below the laboratory limit of quantification will be treated conservatively.
