Fibronectin expression as a marker of hypoxia in asphyxial deaths: A pilot study

Tommaso D'Anna; Rosario Barranco; Simona Merighi; Valeria Cancila; Ginevra Malta; Stefania Zerbo; Giuseppe Davide Albano; Giuseppe Di Pietrantonio; Isabella Caristo; Francesco Ventura; Antonina Argo; Beatrice Belmonte

doi:10.1016/j.legalmed.2026.102820

Fibronectin expression as a marker of hypoxia in asphyxial deaths: A pilot study

Leg Med (Tokyo). 2026 Feb 23:82:102820. doi: 10.1016/j.legalmed.2026.102820. Online ahead of print.

Affiliations

¹ Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy; Tumor Immunology Unit, Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy; Legal Medicine Unit, Policlinic University Hospital "Paolo Giaccone", Via del Vespro 129, 90138 Palermo, Italy.
² Department of Legal and Forensic Medicine, Health Science Department (DISSAL), University of Genoa, Via De Toni, 12, 16132 Genoa, Italy; I.R.C.C.S. Ospedale Policlinico San Martino Teaching Hospital, Largo Rosanna Benzi, 10, 16132 Genoa, Italy.
³ Tumor Immunology Unit, Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy.
⁴ Section of Legal Medicine, Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy.
⁵ Legal Medicine Unit, Policlinic University Hospital "Paolo Giaccone", Via del Vespro 129, 90138 Palermo, Italy; Section of Legal Medicine, Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy.
⁶ Department of Legal and Forensic Medicine, Health Science Department (DISSAL), University of Genoa, Via De Toni, 12, 16132 Genoa, Italy.
⁷ Tumor Immunology Unit, Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy. Electronic address: beatrice.belmonte@unipa.it.

PMID: 41785781
DOI: 10.1016/j.legalmed.2026.102820

Abstract

Aim: Asphyxial deaths represent a major diagnostic challenge in forensic practice, as classical morphological signs are nonspecific and may overlap with other causes of sudden death. Fibronectin (FN), an extracellular matrix glycoprotein sensitive to hypoxia, is emerging as a candidate biomarker of oxygen deprivation. We investigated its expression in cardiac tissue from asphyxial deaths compared with traumatic controls.

Methods: We retrospectively collected formalin-fixed, paraffin-embedded left ventricular myocardium from autopsies in Palermo and Genoa (2021-2025). The cohort included 54 cases: 45 asphyxial deaths (5 smothering, 4 strangulation, 15 hanging, 17 drowning, 4 chemical asphyxia) and 9 non-asphyxial traumatic controls. We performed FN immunohistochemistry (IHC) with a monoclonal antibody and quantified FN-positive cardiomyocytes using dedicated image-analysis software.

Results: We found significantly higher FN expression in all asphyxial deaths compared with controls (mean 11.7 ± 3.6%). The highest intensities were observed in smothering (46.1 ± 7.2%) and strangulation (45.0 ± 8%), followed by chemical asphyxia (35.1 ± 9.8%), hanging (27.8 ± 6.6%), and drowning (21.4 ± 5.9%). FN levels varied between subgroups, but their consistent elevation confirms its reliability as a marker of hypoxic injury in asphyxia.

Conclusion: FN upregulation in the myocardium is a consistent hallmark of asphyxial deaths, reflecting extracellular matrix changes under hypoxia. FN identifies hypoxic stress rather than mechanism-specific asphyxia; nonetheless, it can be a valuable aid in forensic diagnosis, especially when morphology alone is inconclusive. Integration of FN IHC with conventional autopsy and histology could enhance diagnostic accuracy and support medicolegal assessments of asphyxial death.

Keywords: Asphyxial deaths; Fibronectin; Forensic pathology; Hypoxia biomarkers; Immunohistochemistry.