Estimation of Chronological Age from Postmortem Tissues Based on Amino Acid Racemization

Abstract

Skin and cartilage tissue specimens from 32 male and 13 female corpses aged between 17 and 50 years were collected within 24 h after the death. Each specimen was analyzed for the composition of dextro (D) and levo (L) forms of aspartate, glutamate, and alanine. Linear regression models were constructed using ln [(1 + D/L)/(1 - D/L] equation to define the relationship between the extent of racemization and the chronological age. Aspartate D/L rates from cartilage showed high correlation (r = 0.779, p < 0.001, n = 45). Aspartate D/L rates from skin showed very low correlation (r = 0.356, p < 0.002, n = 44). The multilinear regression model of both aspartate D/L rates of cartilage and skin tissues in 44 cases yielded a coefficient of r = 0.828 (p < 0.001). In conclusion, only racemization rate of Aspartate both in the skin and the cartilage tissues correlated with the chronological age. Our results may imply that the age can be estimated more precisely if two different tissue specimens are obtained from one corpse.

Metode procjene dentalne dobi kod odraslih osoba

“…Morfološke metode korištene u procjeni dentalne dobi često su neprecizne jer su subjektivne, odnosno ovise o iskustvu forenzičnog stomatologa. Biokemijske su metode, s druge strane, objektivne jer se rezultati dobivaju na osnovi specifičnih kemijskih postupaka s kvantificiranim rezultatom 34,35 . Starenjem tkivni proteini prolaze kroz niz neenzimatskih, spontanih reakcija.…”

“…Dakle, što je osoba starija, u tkivima će imati veći udio D-forme aminokiselina. Smrću se ovaj proces zaustavlja 35,36 . Asparaginska kiselina je aminokiselina koja ima najveći stupanj racemizacije i zbog toga se koristi u ovim mjerenjima 37 .…”

“…Asparaginska kiselina je aminokiselina koja ima najveći stupanj racemizacije i zbog toga se koristi u ovim mjerenjima 37 . Također, racemizacija asparaginske kiseline pokazala je najveću povezanost s kronološkom dobi u odnosu na druge aminokiseline 35 . U tijelu se nalazi u kostima, elastinu, intervertebralnim diskovima te u dentinu i cementu.…”

Amino acid racemization and its relation to geochronology and archaeometry

“…A current summary of the correlation coefficients between AAR rate and actual age in various studies found in the literature has been provided by Tiplamaz et al. .…”

“…A number of previous studies on cartilage tissues with forensic applications have reported a high or moderate correlation between the Asp racemization rate and age . A recent study was conducted to compare the correlation of the racemization rates of Asp, Glu, and Ala amino acids from postmortem tissues (specifically ear cartilage and gluteal skin tissues) to a human's chronological age . A current summary of the correlation coefficients between AAR rate and actual age in various studies found in the literature has been provided by Tiplamaz et al.…”