Research paperThe effect of sex hormones on bone metabolism of the otic capsule – an overview
Introduction
The aim of the present contribution is not to review the literature on bone metabolism of the otic capsule. The aim is rather to bring together seeming disparate reports – old, new, forgotten or ignored – which in isolation have little impact but when taken together they consolidate todays interest in the influence of sex hormones on the inner ear. In particular, It is hoped that this overview will open the way to further interest in other interacting hormones and, in particular, prolactin which might affect the inner ear.
Section snippets
Sex hormones affect the inner ear
When interested in the effects of hormones and the inner ear, a rapid browse of some recent literature reveals that estrogen and more particularly receptor Β is involved in the protection against acoustic trauma (Meltser et al., 2008) while hormone therapy, including progestin together with estrogen, can damage hearing (Guimaraes et al., 2006). These seemingly conflicting data come years after case reports of irreversible (Okulicz, 1978) or reversible hearing loss (Hanna, 1986), tinnitus (Mitre
Hormones underlie osteoporosis – does prolactin play a role?
Osteoporosis in post-menopausal women has long been associated with the fall in estrogen levels – thus contributing to justification for the continued use of hormone replacement therapy in women. Bone loss in post-menopausal women typically occurs in two phases – a rapid phase, related to the lack of estrogen on bone metabolism, which can last several years, and a slow phase, related to the calcium homeostasis, of indefinite duration (Riggs, 2002). While estrogen is probably a major actor,
Hormones and otosclerosis
Otosclerosis is a chronic inflammatory infection of the otic capsule resulting in bone resorption. The pathology has a complex etiology and the state of the art has been reviewed recently (Arnold, 2007). The measles virus has been pin-pointed as one crucial contributing factor. The virus was first detected by immunohistochemistry in otosclerotic lesions and measle virus specific antibodies have been detected in perilymph (Arnold et al., 1996). While only 1% of the population may develop
Molecular basis of bone metabolism – and the otic capsule
Healthy bone metabolism involves the coupling between bone formation and bone resorption via osteoblasts and osteoclasts respectively. Loss of function of osteoclasts is known as osteopetrosis, gain of function of osteoblasts as osteoclerosis and relative increase of bone resorption over bone formation as osteoporosis. Our present understanding of bone metabolism largely considers the role of three members of the tumor necrosis factor (TNF) and TNF receptor families of proteins (Boyle et al.,
Hormones affect the molecular control of bone metabolism – estrogen versus prolactin
While the RANKL–RANK–OPG system now appears to be determinant in the control of bone metabolism, the system is regulated by hormones. Estrogen has its protective effect on bone because it can inhibit bone resorption by inducing apoptosis of osteoclasts (Kameda et al., 1997) and blocking the maturation of osteoclasts (Pacifici, 1996). Estrogen has now been found to stimulate OPG in osteoblastic cells (Hofbauer et al., 1999) and to decrease the response of osteoclasts to RANKL (Srivastava et al.,
Prolactin is linked to other labyrinthine pathologies
As discussed above pregnancy, lactation, contraceptive pills, and hormone replacement therapy, are conditions affecting bone structure and have, only loosely, been related to different types of labyrinthine dysfunctions. While estrogen is accepted as a possible actor, the same cannot be said for the role of prolactin. However, further supporting evidence for this hypothesis comes from other pathologies.
Ménière’s disease is characterized by hearing loss, tinnitus and vestibular dysfunction. It
Future in molecular bone therapy of the otic capsule
Fundamental studies on molecular mechanisms of bone resorption in the past ten years have given way to therapeutical approaches aimed at inhibiting RANKL and protecting bones (Schwarz and Ritchlin, 2007). For example a single dose of OPG in post-menopausal women was reported to substantially reduce bone turnover and for a sustained period (Bekker et al., 2001). These and other data provide encouraging basis for the development of clinical anti-RANKL therapy for bone diseases (Hofbauer and
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The impact of menopausal status on auditory brainstem responses
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2023, Brazilian Journal of OtorhinolaryngologyOtosclerosis: From Genetics to Molecular Biology
2018, Otolaryngologic Clinics of North AmericaCitation Excerpt :These hypotheses are based on, at least in part, the difference in disease prevalence between men and women, the observation that otosclerosis often manifests around the time of pregnancy, and the established role of estrogen in bone metabolism. Although there are case reports of hearing loss with oral contraceptive and hormone replacement therapy, in a large cohort study of approximately 17,000 women followed for periods up to 26 years, no association between oral contraceptive use and the development of otosclerosis was identified.36,37 Recent studies suggest otosclerosis is predominantly a complex or multifactorial disease with variable genetic and environmental factors contributing to the development of a similar pathology.11,13,38
Aging of the auditory system
2015, Handbook of Clinical NeurologyCitation Excerpt :Moreover, the known prothrombotic effect of conceptive pills might play a role. Nevertheless, human studies investigating the effect of sex hormones on hearing show an influence of estrogen (Horner, 2009). The estrogen receptors, alpha and beta, are localized where electric impulses are transmitted (inner and outer hair cells, spiral ganglion) and where inner-ear homeostasis is maintained (stria vascularis, spiral ligament) (Stenberg et al., 2002); therefore, estrogens seem to have a role in signal transmission and cochlear homeostasis.
Effects of estradiol in adult neurogenesis and brain repair in zebrafish
2013, Hormones and BehaviorCitation Excerpt :Estrogens are steroid hormones that sustain important physiological functions and exert pleiotropic effects on many target organs such as the gonads, the cardiovascular system, the liver, the skeleton, and the nervous system (Bazer et al., 2010; Boonyaratanakornkit et al., 2007; Couse and Korach, 1999; Horner, 2009; Karasu et al., 2011; Le Roux and Reh, 1994; Matthews and Gustafsson, 2003; Mesiano et al., 2011; Pettersson and Gustafsson, 2001; Zakar and Mesiano, 2011).
GPER-1 and sex-hormone levels in patients with otosclerosis
2020, American Journal of Otolaryngology - Head and Neck Medicine and SurgeryCitation Excerpt :Estrogens are known as female sex-hormones, but they are also effective in many other functions in our body such as bone growth, cell proliferation, glucose and lipid metabolism, inflammation and vascular tonus [10]. In a previous study by Imauchi et al. estrogens were found to have an inhibitory effect on bone resorption by directly inhibiting osteoclast activity as well as decreasing auto- and paracrine production of cytokines such as IL-1 and -6, and tumor necrosis factor-alpha (TNF-alpha) [4,15,16]. Increased expression of TNF-alpha has been demonstrated in active otosclerosis, which may lead to extensive osteoclast activation and bone resorption[17].