Microplastic Contamination in Kidney Transplant Donor Tissues and Its Association with Early Post-Transplant Blood Pressure Changes in Recipients: A Multi-modal Analytical Study

Microplastic (MP) contamination in human tissues is an emerging environmental and clinical concern, yet its relevance to organ transplantation remains poorly understood. This study characterized MPs in kidney transplantation-associated donor tissues and examined their relationship with early postoperative blood pressure (BP) in recipients. Tissue samples, including kidney, adrenal gland, renal artery, renal vein, and ureter, were collected from 28 kidney transplant donors. MPs were extracted from each tissue and analyzed using a multimodal strategy: pyrolysis-gas chromatography-mass spectrometry for polymer quantification, laser direct infrared spectroscopy (LD-IR) for particle identification, and scanning electron microscopy (SEM) for morphological assessment. Polyethylene (PE) and polyvinyl chloride (PVC) were consistently the most abundant polymers by mass, with PE concentrations ranging from 25.7 to 98.9 μg/g and PVC from 31.2 to 65.4 μg/g across tissues. LD-IR analysis showed that kidney tissue contained 293 MP particles (6 polymer types), adrenal gland 2017 (9 polymer types), renal artery 881 (8 polymer types), renal vein 1528 (10 polymer types), and ureter 1672 (10 polymer types). MPs measuring 20-100 μm accounted for 47.1-54.9 % of its content across tissues, while 100-500 μm MPs comprised 45.1-52.9 %. Postoperative BP was assessed 15 days post-transplantation. While moderate, tissue-specific correlations between certain MP types and BP were observed (e.g., natural rubber in adrenal glands, polycarbonate in renal arteries, polypropylene in renal veins, and butadiene rubber in ureters), most associations were not statistically significant. Negative values were obtained for linear regression and FDR correction, emphasizing the preliminary nature of the results. This highlights the need for further investigation of the clinical impact of MP.