Estimation of Postmortem Interval Based on the Third Component of Complement (C3) Cleavage

Abstract

To estimate postmortem interval (PMI), the spontaneous conversion of the native third component of complement (C3) to its derived fragments in whole blood was studied by crossed immunoelectrophoresis. C3 cleavages in vitro at different temperatures showed that the incubation of whole blood at a higher temperature led to a faster conversion of beta 1C (native C3) to beta 1A (C3c). In cadaveric blood, we found a significant positive correlation between percentage of C3 cleavage and PMI. From these results, it is possible to estimate PMI from the ratios of C3 cleavage.

Promising blood-derived biomarkers for estimation of the postmortem interval

“…61 Some authors have proposed PMI estimation based on the effect of the PMI on protein concentrations. 8,[28][29][30]62,63 According to our results, the total protein concentration initially increased, up to 48 h, reaching a plateau that remains unchanged until the end of the experiment. The albumin concentration in vitro increased slightly up to 216 h and then decreased over the remaining putrefaction time.…”

“…The estimation of the PMI based on the third component of C3 cleavage was previously studied in postmortem blood, where a significant positive correlation between the percentage of C3 cleavage and PMI was found. 62 Additionally, we observed a decrease in the immunoglobulin G and M concentrations with the putrefaction time. However, the immunoglobulin A concentration remained practically constant up to 120 h, decreasing over the remaining time.…”

Estimation of Death Time

“…Kominato et al investigated the conversion of a complement factor (C3) to its constituent fragments in the blood for the determination of PMI by immune electrophoresis and suggested that there was a statistically significant correlation between C3 degradation and PMI, and thus, it was reported that PMI could be predicted by looking at the C3 fragmentation rate [24]. Endo et al measured monoamine metabolites in the cerebrospinal fluid and observed that the concentration of 3-4 dihydroxyphenylacetic acid increased with time after death and reported that it could be used in the determination of PMI [25].…”

“…The methods mentioned in the above-mentioned literature generally remain as methods that are not used much in practice at the experimental level [1][2][3][22][23][24][25][26][27][28][29][30][31]. However, the question of the exact time of death remains on the documents pertaining to the autopsy request made by the prosecution offices.…”

“…For every answer to be stated in the autopsy report for this question, it should be emphasized there is no specific scientific method that can give a definite result on this subject. Subjective and empirical estimates can be made about the time of death in the form of intervals, and the estimates obtained in the form of time intervals they receive from us will need to be supported by forensic investigations [1][2][3][22][23][24][25][26][27][28][29][30][31].…”