Micro- and nanoplastics and the kidney: human evidence, clinical vulnerabilities, dialysis-related exposure, and CKD

Micro- and nanoplastics (MNPs) have recently been identified in human kidney tissue, urine and bloodstream, raising concerns about their potential contribution to renal dysfunction. Epidemiological and clinical studies, although still limited, increasingly link exposure to MNPs and their associated contaminants, such as PFAS, bisphenols and phthalates, are associated with reduced estimated glomerular filtration rate (eGFR), albuminuria, hypertension, metabolic alterations and an increased risk of developing chronic kidney disease (CKD). MNPs may exert both direct effects, through theoretical mechanical clogging, tubular injury, oxidative stress and inflammation, and indirect effects by acting as vectors for toxic co-contaminants.Patients with CKD represent a high-risk group because of reduced renal clearance, increased susceptibility to oxidative and inflammatory stress, and frequent exposure to medical-grade plastics. Dialysis patients constitute the most informative human model of chronic plastic exposure. Each haemodialysis session involves direct blood contact with PVC tubing spallating in rollerpumps, polysulfone or polyethersulfone membranes and polycarbonate components that may release bisphenols and phthalates. In addition, water treatment systems and peritoneal dialysis bags may contribute to MNP exposure through leaching and material degradation, creating a unique and sustained “plastic burden” with potential systemic and renal consequences.This review summarizes available evidence of human pathology, discusses the specific vulnerability of CKD, dialysis, transplanted and paediatric populations, and outlines research priorities and public health strategies. Recognizing MNPs and plastic-associated chemicals as emerging, potentially modifiable environmental determinants of kidney health is crucial for risk stratification, device design, regulatory policies and Planetary Health-oriented nephrology practice.