Microplastics in Brain Hematomas and Neurological Outcomes After Intracerebral Hemorrhage

Spontaneous intracerebral hemorrhage is a severe and life-threatening neurological condition representing approximately 10-15% of all strokes worldwide and is associated with high early mortality and substantial long-term disability. Despite significant advances in neuroimaging, neurosurgical techniques, and neurocritical care, clinical outcomes remain poor, and the biological mechanisms underlying hemorrhage initiation, expansion, and secondary brain injury are still incompletely understood.

The pathophysiology of intracerebral hemorrhage is characterized by a complex interplay of vascular, inflammatory, and neurotoxic processes. Structural vascular alterations, endothelial dysfunction, and disruption of the blood-brain barrier contribute to vessel rupture and hematoma formation. Following the initial bleeding event, secondary brain injury is driven by hematoma-induced mechanical damage, oxidative stress, activation of resident and infiltrating immune cells, and release of pro-inflammatory mediators. Microglial activation, macrophage infiltration, and inflammasome-related pathways are recognized as important contributors to neuronal injury and neurological deterioration.

While traditional risk factors such as hypertension and small vessel disease are well established, the contribution of environmental exposures to cerebrovascular vulnerability has been largely overlooked. In recent decades, environmental exposure to micro- and nanoplastics has emerged as a global health concern. The exponential increase in plastic production has resulted in widespread distribution of plastic-derived particles across ecosystems, leading to chronic human exposure through ingestion, inhalation, and dermal contact.

Microplastics and nanoplastics have been detected in multiple biological matrices, including blood, lung tissue, placenta, and cardiovascular structures. Experimental and translational studies suggest that these particles may interact with biological systems by promoting oxidative stress, immune activation, endothelial dysfunction, and tissue inflammation. Microplastics and nanoplastics have also been described in vascular tissues, supporting the rationale for investigating their potential association with cerebrovascular disease.

The central nervous system is particularly susceptible to vascular and inflammatory insults, and preservation of blood-brain barrier integrity plays a critical role in maintaining neural homeostasis. Emerging evidence indicates that nanoscale particles may cross biological barriers and potentially contribute to neuroinflammation, microglial activation, and neuronal dysfunction. However, the presence, distribution, and potential biological impact of microplastics and nanoplastics in cerebrovascular diseases, particularly intracerebral hemorrhage, have not been systematically investigated.

The PARTENOPE study (Plastic Accumulation in Residual Brain Tissues from Hemorrhagic Events: Neurological Outcomes and Pathogenetic Evidence) has been designed to address this knowledge gap. This observational cohort study integrates retrospective and prospective data collection and adopts a translational approach combining clinical characterization, advanced analytical chemistry, and biological investigation.

Study Design and Population

The study includes adult patients diagnosed with spontaneous intracerebral hemorrhage undergoing neurosurgical hematoma evacuation. Both retrospectively identified cases and prospectively enrolled patients are included to capture a broad spectrum of clinical presentations and improve the robustness and generalizability of findings.

Patients with traumatic intracranial hemorrhage, intracranial neoplasms, or vascular malformations are excluded to ensure a homogeneous population focused on primary spontaneous hemorrhagic events.

Biological Sample Collection and Contamination Control

Intracerebral hematoma samples are collected intraoperatively using standardized protocols specifically designed to minimize environmental contamination. Measures include the use of non-plastic surgical instruments, glass collection systems, and controlled laboratory environments to preserve sample integrity and minimize external contamination.

Peripheral blood samples are obtained to assess systemic exposure to microplastics and nanoplastics and to enable comparative analyses between circulating and tissue-associated particle burden.

Analytical Characterization of Microplastics and Nanoplastics

Identification and characterization of microplastics and nanoplastics are performed using a multimodal analytical platform integrating advanced spectroscopic and imaging techniques. These techniques include scanning electron microscopy with energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, and pyrolysis gas chromatography-mass spectrometry.

This integrated analytical approach enables high-resolution characterization of particle size, morphology, and polymer composition. Quantitative analyses provide estimates of particle burden within hematoma tissue, while qualitative analyses identify polymer types and potential environmental sources.

Spatial mapping analyses are also conducted to determine localization of particles within the hematoma matrix, including their presence in extracellular compartments and their potential interaction with inflammatory cells such as macrophages.

Clinical and Radiological Characterization

Comprehensive clinical data are collected, including demographic variables, cardiovascular risk factors, medication exposure, and comorbid conditions. Radiological assessment includes hematoma volume, location, and imaging characteristics derived from computed tomography and magnetic resonance imaging.

Perioperative variables, surgical techniques, and postoperative management are also recorded to enable integrated analysis of clinical and biological determinants of outcome.

Outcome Assessment

Patients are followed longitudinally to evaluate neurological and clinical outcomes using standardized clinical, radiological, and biological assessments.

Primary and Secondary Objectives

The primary objective of the study is to evaluate the presence and burden of microplastics and nanoplastics in intracerebral hematoma tissue and to investigate their association with neurological and cerebrovascular outcomes.

Secondary objectives include:

• evaluating the relationship between circulating and tissue-associated particle levels
• assessing the association between particle burden and inflammatory responses
• exploring the potential contribution of microplastics and nanoplastics to hematoma progression and recurrence
• characterizing the physicochemical properties and distribution of detected particles

Mechanistic and Exploratory Analyses

Exploratory analyses aim to investigate potential mechanistic pathways linking microplastic and nanoplastic exposure to neurovascular injury. These include evaluation of oxidative stress pathways, immune cell activation, endothelial dysfunction, and inflammatory signaling cascades.

Particular attention is given to macrophage activation, microglial response, and inflammasome-related pathways that may contribute to secondary brain injury after hemorrhage. The interaction between microplastics and nanoplastics and the blood-brain barrier is also explored, including their potential contribution to barrier dysfunction and increased vascular permeability.

Scientific and Clinical Implications

The PARTENOPE study represents one of the first systematic investigations of microplastics and nanoplastics in intracerebral hemorrhage. By integrating environmental exposure science with clinical neurology and advanced analytical techniques, this study aims to provide novel insights into the potential role of environmental pollutants in cerebrovascular disease.

If an association between microplastic and nanoplastic accumulation and adverse clinical outcomes is identified, these findings may have important implications for risk stratification, prevention strategies, and future research on environmental determinants of neurological disease.

Ultimately, this study seeks to contribute to a more comprehensive understanding of the factors influencing cerebrovascular health and disease progression.