Quantitative analysis of the expression of caspase 3 and caspase 9 in different types of atherosclerotic lesions in the human aorta

The existing data on apoptotic processes in human atherosclerotic lesions is insufficient and is often contradictory. This study was undertaken to evaluate the levels of the expression of key apoptosis-related genes, namely, caspase 3 (CASP3) and caspase 9 (CASP9) in the normal (non-atherosclerotic) intima of the human aorta in comparison with those in different types of atherosclerotic lesions. Twenty-five autopsy samples of thoracic aorta were examined by polymerase chain reaction (PCR) analysis. The study revealed that the expressions of CASP3 and CASP9 genes were changed in different types of atherosclerotic lesions in course of the progression of the disease, but not in a unanimous way. The mRNA expression of CASP3 was found to be steadily decreasing with the progression of atherosclerosis while the expression of CASP9 showed a pattern which can be described as a “bell-shaped” relationship between gene mRNA expression and the type of atherosclerotic lesion, with the maximum being observed in fatty streaks. The fall in CASP3 expression may be associated with cellular senescence as well as with the domination of necrotic processes in atherosclerotic lesions, as shown by electron microscopic analysis. Our study provides novel quantitative data on the expression of CASP3 and CASP9 genes in different atherosclerotic lesions in the human aorta and thus, might assist in better understanding of the processes occurring during the development of lesions in human atherogenesis.