Post-mortem forensic application of proteomics on human ribs: Investigating the phenomenon of vital reaction

The research upon vital reactions is a hot topic in forensic pathology. However, there are very few studies which focus on the bone tissue and scientific data are currently limited to conventional histopathology. The skin and the muscle are also faster than the bone in the healing process. Therefore, the possibility to establish the timing of skeletal traumatic injury is difficult especially for short survival times (peri-mortem interval). For these reasons, bone marrow may represent a dynamic and potentially useful substrate for the identification of bone lesion vitality. Furthermore, novel omics techniques such as the untargeted proteomics could really improve the investigation of reliable forensic markers. This study provides the application of proteomics on human bone marrow of traumatized ribs with the purpose to a) define a significant pattern of vital reaction on broken ribs versus undamaged ones; b) evaluate the proteomic changes over different known survival times; c) assess proteomic differences among resuscitation fractures versus other types of rib traumas (e.g., vehicle and train crashes, falling from heights). The trauma group significantly (q < 0,001) overexpresses acute-phase inflammatory proteins, different extracellular matrix proteins, and bone-related specific proteins. Noteworthy, some of these proteins show very interesting patterns such as complement C9 which provides the best significant results over time, fibrinogen which statistically increases starting from 4 h after trauma, and carbonic anhydrase 2 which is linearly overexpressed in the first 12 h. There are no statistical differences between resuscitation fractures versus other types of rib blunt injuries.