IADR Abstract Archives
The Role of Estrogen in OPG – RANKL System: A Review
Objectives: The objective of this review is to identify, evaluate and synthesize available evidence about how estrogens affect the levels of OPG and RANKL expression and synthesis.
Methods: Pubmed search, with strategy (("Estrogens"[Mesh]) AND "RANK Ligand"[Mesh]) AND "Osteoprotegerin"[Mesh] and Google Scholar introducing the descriptors “Estrogen”, “RANKL” and “Osteoprotegerin”. Longitudinal studies in English of the last 10 years were included; excluding prospective studies, languages other than English and longer than 10 years of publication. The selection was made in duplicate based on the abstract and title.
Results: A total of 43 articles were found from the search, of which 11 were selected according to the exclusion and inclusion criteria already mentioned.
Conclusions: The level of bone mass reflects a balance between bone formation and resorption, which at the molecular level involves the coordination between osteoblasts and osteoclasts; with the molecular triad OPG/RANK/RANKL being a key factor in this balance. Several studies show that hormone levels are a modulating pathway of bone mass, with estrogen being the main regulating hormone, where, in the face of low levels, the metabolism points to a reduction in bone mass. Otherwise it happens in front of high levels where the metabolism points towards an increase of the bone mass. This is observable in studies performed with cases of postmenopausal osteoporosis or in studies with ovariectomized rats. Little is known so far about the role that estrogen would play as regulating hormone of the OPG/RANK/RANKL axis.
All of the studies assign to estrogen an up-regulation function for OPG expression and down-regulation for RANKL, indicating that it would be an important anti-reabsorption factor in the regulation of the OPG/RANKL system. However, the relationship between levels of this hormone and the development and progression of periodontal diseases is still unclear, and in vivo research is needed on its effect on osteodestructive periodontal diseases.
Methods: Pubmed search, with strategy (("Estrogens"[Mesh]) AND "RANK Ligand"[Mesh]) AND "Osteoprotegerin"[Mesh] and Google Scholar introducing the descriptors “Estrogen”, “RANKL” and “Osteoprotegerin”. Longitudinal studies in English of the last 10 years were included; excluding prospective studies, languages other than English and longer than 10 years of publication. The selection was made in duplicate based on the abstract and title.
Results: A total of 43 articles were found from the search, of which 11 were selected according to the exclusion and inclusion criteria already mentioned.
Conclusions: The level of bone mass reflects a balance between bone formation and resorption, which at the molecular level involves the coordination between osteoblasts and osteoclasts; with the molecular triad OPG/RANK/RANKL being a key factor in this balance. Several studies show that hormone levels are a modulating pathway of bone mass, with estrogen being the main regulating hormone, where, in the face of low levels, the metabolism points to a reduction in bone mass. Otherwise it happens in front of high levels where the metabolism points towards an increase of the bone mass. This is observable in studies performed with cases of postmenopausal osteoporosis or in studies with ovariectomized rats. Little is known so far about the role that estrogen would play as regulating hormone of the OPG/RANK/RANKL axis.
All of the studies assign to estrogen an up-regulation function for OPG expression and down-regulation for RANKL, indicating that it would be an important anti-reabsorption factor in the regulation of the OPG/RANKL system. However, the relationship between levels of this hormone and the development and progression of periodontal diseases is still unclear, and in vivo research is needed on its effect on osteodestructive periodontal diseases.