Mechanisms of Ageing and Development

Menopause is a stage in a woman’s life characterized by twelve months of amenorrhoea. This transition happens due to changes in ovarian follicular activity, leading to endocrine, biological and clinical modifications. The main hormones related to these changes and symptoms are oestradiol, LH, FSH, AMH, Inhibin B and GnRH. It is important to point out that the skin is very affected by all these hormone changes, leading to a decrease in collagen content, water content, elasticity, thickness and impacting on all skin layers quality. Aiming to help women go through this period of their lifetimes with a better quality of life, cosmetic and pharmaceutical industries have studied formulations to improve skin quality. In order to study the safety and efficacy of these products, in vitro methods have been developed in order to mimic menopause and aged skin. In addition to that, many clinical methodologies for skin features assessment have also been improved and applied to evaluate the efficacy of treatments or compounds for menopause. Studying and improving skin models and skin evaluation methodologies may help in the identification of therapeutic targets, treatments, drugs and cosmetics along with new insights for future research in the dermatology field. 1. What is menopause? Menopause consists of a stage in a woman’s life when reproductive capacity ceases (De Souza and Araújo, 2015). This happens due to a decline in ovarian follicular activity (Nair, 2014). Clinically, it can be defined as the period of time in a woman’s life after twelve consecutive months of amenorrhoea with no other pathological or physiological aetiology. It is important to point out, however, that it is not a sudden process; in most women, menopause is preceded by a period (generally four years) during which many endocrine, biological and clinical changes are occurring (Burger, 2006). Due to the life expectancy in most countries, many women are expected to live one-third of their lives in this time period (Burger, 2006). However, this landmark goes beyond the absence of menstruation and oestrogen decline (Parand avar et al., 2014); menopause brings with it many insecurities as it generally occurs during the period of life when women play important roles in society (Monteleone et al., 2018). Approximately one billion women have experienced menopause worldwide, and this process is associated with three types of crisis: social, biological and psychological (Parand avar et al., 2014). Consequently, women who have undergone this phase of life need to have support that meets their needs at this moment (Hoga et al., 2015). This is why menopause matters. To date, there are 1050 clinical trials that have been performed or are happening worldwide regarding menopause and their symptoms (U.S. National Library of Medicine, 2019). 2. What is behind the scenes? The key players What happens to a woman’s body that leads to these symptoms? Many physiological changes happen in this period, and several hormones are key players in these alterations. Oestrogens are the most well-known of the hormones linked to menopausal symptoms. The decline in ovarian oestrogen production is certainly responsible for most of the consequences of menopause. However, many different protagonists contribute to this decline, such as hypothalamic and ovarian ageing, as well as environmental, lifestyle and genetic factors, leading to changes in many other hormones other than oestrogen (Davis et al., 2015). The menopausal transition involves a time of hormonal instability, and the endocrine changes are primarily a consequence of the reduced number of ovarian follicles. Among all the hormones, FSH, antiMullerian hormone (AMH), inhibin B and oestradiol are the hormones that exhibit more subtle changes during this period of time (Burger et al., 2007; Su and Freeman, 2009). The changes during menopause https://doi.org/10.1016/j.mad. 2019.111193 Received 12 July 2019; Received in revised form 22 November 2019; Accepted 2 December 2019 ⁎ Corresponding author at: Grupo Boticário, Research & Development, Rui Barbosa Avenue, 4110, São José dos Pinhais, Paraná, Zip Code 83055-320, Brazil. E-mail addresses: thamile.reus@grupoboticario.com. br (T.L. Reus), carla@grupoboticario.com. br (C.A. Brohem), desirees@grupoboticario.com. br (D.C. Schuck), marciolo@grupoboticario.com. br (M. Lorencini). Mechanisms of Ageing and Development 185 (2020) 111193 Available online 04 December 2019 0047-6374/ © 2019 Elsevier B.V. All rights reserved. T