Method: To that end, human odontoblasts were analyzed from 40 healthy permanent teeth, divided into two age groups (young and adult), dental pulp coronal samples were processed for immunocytochemistry with antibodies against mitochondrial (MTCO2) and lysosomal (LAMP2) markers and analyzed by laser confocal microscopy and transmission electron microscopy.
Result: In young patients, odontoblasts showed a well-developed mitochondrial network and a concentration of mitochondria around heterogeneous autophagic vacuoles closely related to the nuclei and heavily surrounded by lysosomes. In adult odontoblasts, mitochondrial components were restricted to the nuclear periphery and surround enlarged deposits of lipofuscin. An increase in lysosomal reaction was observed in colocalisation with large lipofuscin deposits.
Conclusion: The mitochondrial network undergoes age-related morphological changes and cellular debris, visualized as lipofuscin deposits within lysosomal compartments, accumulates with age. We postulate that alterations of the mitochondrial and lysosomal system are central to the cellular aging process of human odontoblasts.