IADR Abstract Archives
Link Between Ageing and Autophagy in Human Pulpal Odontoblasts
Objectives: Aged post-mitotic cells accumulate biological waste as defective mitochondria and non-degradable protein aggregates. The mechanisms of ineffective waste disposal systems are not well understood in human pulp. The aim of the study is to examine and compare the immunohistochemical distribution of COX2, LAMP2 and MAP LCII3 in human odontoblastic cells depending on age, gender, tooth type and cell topography (crown/root areas).
Methods: Ninety intact teeth of healthy individuals were enrolled in the study and arranged in three groups (n=30 in each group) regarding the patients’ age: tooth germs with young pulp (14-16 years old), adult/mature pulp (18-40 years old) and senescent pulp (41-78 years old) groups. All teeth were freshly extracted due to orthodontic indications (dental germs of third molars), difficult eruption (third molars) and periodontal and bone lost (premolars and incisors). The specimens were fixed overnight in 10% buffered paraformaldehyde, decalcified in a 3% hydrochloric acid (HCl) for 6 hours and paraffin embedded. Immunohistochemistry using mouse monoclonal antibody COX2 (D-5), LAMP2 (H4B4), and MAP LCII3 (G2) Santa Cruz Biotechnology Inc., USA was performed by Leica-Bond Max automated system (Leica Biosystems, Germany). Statistical analysis including Kruskal-Wallis and Mann-Whitney tests were applied (p<0.05) by IBM SPSS Statistics 25.
Results: In aged dental pulp, immunohistochemically odontoblasts expressed statistically significant more COX2 and MAP LCII3 (p<0.05). A greater expression of LAMP2 was shown, but no statistically significant difference was identified (p>0.05). The expression of all biomarkers was not statistically different in upper/lower, posterior/frontal teeth, as well as in males/females specimens (p>0.05). Coronary odontoblasts expressed statistically significant more biomarkers than radicular cells (p<0.05).
Conclusions: Insufficient recycling by mitophagy in aged odontoblasts shows accumulation of mitochondria with defective respiratory functions and further damage of degradation systems resulting in energy cell deficiency and over-oxidative stress. Possible link between ageing and autophagy confirms mitochondrial-lysosomal theory of ageing in odontoblasts.
Methods: Ninety intact teeth of healthy individuals were enrolled in the study and arranged in three groups (n=30 in each group) regarding the patients’ age: tooth germs with young pulp (14-16 years old), adult/mature pulp (18-40 years old) and senescent pulp (41-78 years old) groups. All teeth were freshly extracted due to orthodontic indications (dental germs of third molars), difficult eruption (third molars) and periodontal and bone lost (premolars and incisors). The specimens were fixed overnight in 10% buffered paraformaldehyde, decalcified in a 3% hydrochloric acid (HCl) for 6 hours and paraffin embedded. Immunohistochemistry using mouse monoclonal antibody COX2 (D-5), LAMP2 (H4B4), and MAP LCII3 (G2) Santa Cruz Biotechnology Inc., USA was performed by Leica-Bond Max automated system (Leica Biosystems, Germany). Statistical analysis including Kruskal-Wallis and Mann-Whitney tests were applied (p<0.05) by IBM SPSS Statistics 25.
Results: In aged dental pulp, immunohistochemically odontoblasts expressed statistically significant more COX2 and MAP LCII3 (p<0.05). A greater expression of LAMP2 was shown, but no statistically significant difference was identified (p>0.05). The expression of all biomarkers was not statistically different in upper/lower, posterior/frontal teeth, as well as in males/females specimens (p>0.05). Coronary odontoblasts expressed statistically significant more biomarkers than radicular cells (p<0.05).
Conclusions: Insufficient recycling by mitophagy in aged odontoblasts shows accumulation of mitochondria with defective respiratory functions and further damage of degradation systems resulting in energy cell deficiency and over-oxidative stress. Possible link between ageing and autophagy confirms mitochondrial-lysosomal theory of ageing in odontoblasts.