Proteomics and biomarkers in estimating postmortem interval through minimally invasive autopsy

• Grant number: 24/00953-2
• Support Opportunities: Regular Research Grants
• Start date: September 01, 2025
• End date: August 31, 2027
• Field of knowledge: Health Sciences - Medicine - Legal Medicine and Deontology
• Principal Investigator: Edna Sadayo Miazato Iwamura
• Grantee: Edna Sadayo Miazato Iwamura
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil
• City of the host institution: São Paulo
• Associated researchers: Andréa Cristina de Moraes Malinverni ; Angela Flávia Logullo Waitzberg ; Paulo Hilário Nascimento Saldiva

Abstract

Studies on post mortem evaluation using minimally invasive procedures began in Brazil between 1800 and 1930. However, despite the date of these studies, their intensification has been since 2010, with their major breakthrough during the COVID-19 pandemic. The post mortem interval is the term used to determine the period of time between the occurrence of death and the moment when the body is found. This interval can be estimated by some evaluations, such as: physical processes of the body, metabolic processes, autolysis, physicochemical and bacterial processes. Despite the existence of these methods for analyzing the post mortem interval, there is a need for studies into new methodologies that enable a more specific evaluation. The overall aim of this project is to evaluate and standardize the post mortem cellular state of liver and muscle fragments, as well as to identify possible biomarkers involved in different post mortem intervals (up to 24, 48, 72 and 120 hours post mortem), based on minimally invasive autopsy. This is a prospective study, covering the years 2024 to 2027, including 36 patients who died aged 18 or over (preferably 5 men and 5 women), from Hospital São Paulo and Serviço de Verificação de Óbitos da Capital (SVOC HC). The samples will only be collected from these individuals with the prior authorization of the family through a free and informed consent form, this project has been approved by the EPM/UNIFESP Research Ethics Committee UNIFESP (CAAE: 78461924.4.0000.5505).Histological sections will be performed for immunohistochemistry with antibodies: Hep-par 1; Desmin and Myosin, using the protocol recommended by the Laboratory of Molecular and Experimental Pathology I of UNIFESP and Hematoxylin and Eosin (HE) staining. The immunohistochemistry and HE slides will be evaluated by collaborating pathologists according to their specialties, to confirm structural alterations and patterns of cellular degradation. To identify possible biomarkers, analysis will be performed through proteomics, the method will be Bottom-up; samples frozen at -80°C will be used, sample preparation will be done according to the protocol of Procopio et al. 2021. The processing of the products will be done by mass spectrometry, based on the mass-charge ratio through ion analysis by liquid chromatography. The data will be analyzed in specific software and compared with databases. (AU)