Suspected Microplastic-like Particles in Human Gastric Autopsy Samples: An Exploratory Histopathological and Biochemical Study

Background: Human exposure to microplastics (MPs) is an emerging public health concern, yet their presence and pathological significance in gastric tissues remain poorly understood. This study investigated suspected MP-like particles in human gastric autopsy specimens, examining their association with histopathological changes and routine biochemical parameters. Methods: A retrospective post-mortem study was conducted on gastric tissue samples from 55 adults who underwent autopsies between 2022 and 2025. Tissue samples were digested using a hydrogen peroxide method, vacuum-filtered, stained with Nile Red, and quantified via ImageJ. Histopathological evaluation using hematoxylin–eosin staining and polarized light microscopy identified tissue-embedded suspected MP-like particles and assessed inflammation, necrosis, and fibrosis. Data were analyzed based on suspected MP-like particle detection status. Results: Suspected gastric MP-like particles were detected in 15 of 55 cases (27.3%). Most positive cases exhibited a low particle burden (median 1/g). Polarized light microscopy additionally served as a technical assessment tool, revealing birefringent structures measuring 26–84 μm within the gastric mucosa or lumen. All suspected MP-like particle-positive cases showed gastric inflammation compared to 35.0% of suspected MP-like particle-negative cases. Fibrosis and necrosis occurred exclusively in the suspected MP-like particle-positive group but lacked statistical significance. No significant associations were found between suspected MP-like particle detection and demographics, comorbidities, or systemic biochemical markers. Conclusions: Suspected gastric MP-like particles were identified in over a quarter of autopsy tissues and were strongly associated with localized gastric inflammation.