Women's health: the struggle to restore hormonal balance

White spotting variant mouse as an experimental model for ovarian aging and menopausal biology

OBJECTIVE

Menopause is a unique phenomenon in modern women, as most mammalian species possess a reproductive period comparable with their life span. Menopause is caused by the depletion of germ cell-containing ovarian follicles and in laboratory studies is usually modeled in animals in which the ovarian function is removed through ovariectomy or chemical poisoning of the germ cells. Our objective was to explore and characterize the white spotting variant (Wv) mice that have reduced ovarian germ cell abundance, a result of a point mutation in the c-kit gene that decreases kinase activity, as a genetic model for use in menopause studies.

METHODS

Physiological and morphological features associated with menopause were determined in female Wv/Wv mice compared with age-matched wildtype controls. Immunohistochemistry was used to evaluate the presence and number of follicles in paraffin-embedded ovaries. Bone density and body composition were evaluated using the PIXImus x-ray densitometer, and lipids, calcium, and hormone levels were determined in serum using antigen-specific enzyme immunoassays. Heart and body weight were measured, and cardiac function was evaluated using transthoracic echocardiography.

RESULTS

The ovaries of the Wv/Wv females have a greatly reduced number of normal germ cells at birth compared with wildtype mice. The remaining follicles are depleted by around 2 months, and the ovaries develop benign epithelial lesions that resemble morphological changes that occur during ovarian aging, whereas a normal mouse ovary has numerous follicles at all stages of development and retains some follicles even in advanced age. Wv mice have elevated plasma gonadotropins and reduced estrogen and progesterone levels, a significant reduction in bone mass density, and elevated serum cholesterol and lipoprotein levels. Moreover, the Wv female mice have enlarged hearts and reduced cardiac function.

CONCLUSIONS

The reduction of c-kit activity in Wv mice leads to a substantially diminished follicular endowment in newborn mice and premature depletion of follicles in young mice, although mutant females have a normal life span after cessation of ovarian function. The Wv female mice exhibit consistent physiological changes that resemble common features of postmenopausal women. These alterations include follicle depletion, morphological aging of the ovary, altered serum levels of cholesterol, gonadotropins and steroid hormones, decreased bone density, and reduced cardiac function. These changes were not observed in male mice, either age-matched male Wv/Wv or wildtype mice, and are improbably caused by global loss of c-kit function. The Wv mouse may be a genetic, intact-ovary model that mimics closely the phenotypes of human menopause to be used for further studies to understand the mechanisms of menopausal biology.

Adjuvant systemic treatment of early breast cancer: the NORA study

BACKGROUND

Despite recommendations contained in international guidelines, factors such as the type of oncology centre, geographic distribution and the introduction of scientific advances into clinical practice can influence the choice of recommended treatment for early breast cancer. The NORA study is a prospective, longitudinal cohort study aimed at investigating tumour characteristics, treatment modalities, and other factors that influence therapeutic choices in early breast cancer patients who have undergone mastectomy or breast-conserving surgery (BCS).

PATIENTS AND METHODS

From January 2000 to early 2004, we collected data on methods of cancer diagnosis, type of surgery and adjuvant medical treatment administered to the first 10 consecutive patients treated in 2000-2002 and the first 20 consecutive patients in 2003 and 2004 at 71 oncology centres in Italy, with the approval of the ethical committee at each centre.

RESULTS

Approximately one-quarter of the cases (26.5%) were detected through screening programmes. BCS was performed in 63.7% and sentinel node biopsy (SNB) occurred in 11.1% of the patients. Of the 3515 total cases, 56.5% were node-negative. Grade 2 cancers comprised 51.3%, and 66.2% were hormone-receptor positive (ER+/PgR+). Chemotherapy (CHT) followed by hormone therapy (HT) was the most prescribed treatment (48.5%). CHT was mainly anthracycline-based (52.9%) and most patients received tamoxifen alone (77.7%) or after CHT (85.2%). For node-negative patients, HR+ and menopause status are the factors influencing the choice to add HT after CHT; patients with HR+ and pT4 tumours are more likely to receive HT instead of CHT. In node-positive patients, the addition of HT is influenced by HR+ status, the opportunity to have HT instead of CHT, and menopause.

CONCLUSIONS

NORA is the first large cohort study to describe the factors that influence therapeutic choices in early breast cancer. Understanding these findings can help physicians in daily clinical practice.