Immunohistochemical distribution of chromogranin A in medicolegal autopsy materials

Chromogranin A (CgA) was recently reported as a marker of various stress responses. The aim of this study was to investigate the immunohistochemical distribution of CgA in human tissues in medicolegal autopsy cases as a basis for postmortem investigation of stress responses. The autopsy cases (n=30, within 48 h postmortem) comprised cases of mechanical asphyxia (n=15: strangulation, n=8; hanging, n=7) and acute myocardial infarction/ischemia (AMI, n=15). Routinely formalin-fixed paraffin-embedded tissue sections, including those of the hypothalamus, pituitary gland, cardiac muscle, lungs, liver, kidneys, spleen, skeletal muscle, skin, thyroid gland, submandibular gland, pancreas, and adrenal gland, were stained with polyclonal anti-human CgA antibodies and CgA positivity was quantitatively examined. Localization of CgA immunopositivity was clearly demonstrated in specific cell components in all tissue sections. CgA was mainly observed in the anterior lobe of the pituitary, adrenal medulla, neurons and some gliocytes in the hypothalamus, submandibular gland, follicular epithelial cells and connective tissue in the thyroid gland and pancreatic islet cells. CgA immunopositivity showed no significant difference between mechanical asphyxia and AMI cases. Positivity was slightly higher in adenohypophysis, adrenal medullar, and pancreatic islet cells (approximately 50-80%) than in the thyroid and submandibular glands (approximately 30-60%); however, a large case difference was observed in hypothalamic CgA immunopositivity (0-100%). These findings suggest that hypothalamic CgA immunopositivity can be used as a marker for investigating individual differences in stress responses during the death process. Further investigation of other causes of death is needed.