DETECTION OF THE 4977 BASE-PAIR MITOCHONDRIAL-DNA DELETION IN PARAFFIN-EMBEDDED HEART-TISSUE USING THE POLYMERASE CHAIN-REACTION - A NEW METHOD TO PROBE SUDDEN CARDIAC DEATH MOLECULAR MECHANISMS

Detection of mitochondrial DNA deletions is performed in fresh or froz en material. At our institute, however, heart samples from subjects re ferred for autopsy are systematically processed for histologic examina tion (that is, paraffin-embedded). We were interested to know if mtDNA deletions can be detected in such material. Our data indicate that: 1 ) the most frequently observed deletion-the 4977 base pair deletion-ca n easily be detected in paraffin-embedded heart tissue; 2) this assay is sufficiently sensitive, since very low levels of the deletion can b e found in normal heart tissue from young adults; and 3) buffeTed form alin appears to be the fixative of choice. Recent literature shows tha t repeated episodes of ischemia result in the accumulation of mtDNA de letions in myocardial cells. Because ischemic heart disease is a major cause of sudden cardiac death, a sensitive method for the detection o f mtDNA damage in myocardial cells will be an important tool to facili tate understanding of unexpected cardiac arrest mechanisms.