Postmortem mRNA quantification for investigation of infantile death: A comparison with adult cases

Previous studies suggested the diagnostic significance of postmortem mRNA quantification in investigating the death process. The present study investigated infantile cases compared with adult cases. Autopsy cases (n = 58, within 48 h postmortem) comprised infants (<1 year of age: mechanical asphyxiation, n = 5; pulmonary infection, n = 14), elderly children (2–8 years of age; pulmonary infection, n = 3), and adults (>20 years of age: mechanical asphyxiation, n = 21; pulmonary infection, n = 13). Quantitative mRNA analyses of glucose transporter (GLUT1) and vascular endothelial growth factor (VEGF) by TaqMan real-time RT-PCR were performed for the bilateral lungs and skeletal muscle (sartorius). In adult cases, lower levels of VEGF mRNA in the lung and higher GLUT1 mRNA in the skeletal muscle were found for pulmonary infection than for asphyxiation. However, there was no significant difference between these causes of death for infants. Compared with adult cases, infantile cases showed a higher VEGF mRNA level in the lungs for pulmonary infection, and higher GLUT1 and VEGF mRNA levels in the skeletal muscle for asphyxiation. For pulmonary infection, both mRNA levels in the skeletal muscle were similar in infantile and adult cases. In older child cases of pulmonary infection, the pulmonary mRNA level of GLUT1 was similar to that in adult cases, and that of VEGF was intermediate between infant and adult levels. These findings indicate a similar death process due to pulmonary infection and asphyxiation in infants; thus, it may be difficult to distinguish these causes of death.