Microplastics and nanoplastics in inflammatory bowel disease: Mechanistic plausibility, human evidence and future research priorities

Table 2 Planned and ongoing human studies evaluating micro- and nanoplastic burden in inflammatory bowel disease

Study title	Ref.	Trial acronym	Registry ID	Study design	Key population	Planned biospecimen	Outcomes	Target enrollment
Microplastic Analysis in Pediatric Inflammatory Bowel Disease	Marszk[111]	MAP-IBD	NCT07141238	Observational case-controlled study; single center	Children < 18 years undergoing clinically indicated colonoscopy, with and without a previous diagnosis of UC or CD	Intestinal mucosal biopsies, stool, urine and blood	Detect and quantify MNPs in intestinal biopsies	40 (20 IBD + 20 controls)
The Presence of Microplastics and Nanoplastics in the Humans Ileum, Colon, and Rectum and Their Relation With Inflammatory Bowel Disease	Sileri[112]	MATISSE	NCT06525558	Cross sections observational case controlled	Adults undergoing planned surgical resection involving ileum, colon or rectum with and without IBD	Resected bowel specimens	Determine presence and characterization of MNPs in bowel tissue and assess correlation with IBD; exploratory metabolomics/proteomics and plastic-exposure assessment	102 (25 UC + 26 CD + 51 healthy controls)
Pregnant Women With and Without Crohn’s Disease to Explore the Role of Plastics and Toxins in Intestinal Inflammation	Agrawal[113]	PLANET	NCT06001450	Prospective observational maternal-infant cohort	Women > 18 years old who are pregnant or planning pregnancy with and without a diagnosis of CD	Maternal stool & saliva; placenta; cord blood; breast milk; infant stool	Measuring the concentration, size and shape distributions of MNPs in stool samples of women with CD, healthy controls and any relatives. Microbiome characterization and fecal calprotectin	46

An additional active research project OPTICS (the impact of microplastics and other synthetic particles on intestinal inflammation in Crohn’s disease) is listed in Aalborg University research portal, however a public registry entry was not identified. UC: Ulcerative colitis; CD: Crohn’s disease; IBD: Inflammatory bowel disease; MNPs: Microplastics and nanoplastics.