High prevalence of benign mammary tumors in a rat model of polycystic ovary syndrome during postmenopausal period

Current Animal Model Systems for Ovarian Aging Research

Ovarian aging leads to menopause, loss of fertility and other disorders in multiple organs, which brings great distress to women. For ethical reasons, it is impossible to use humans as direct study subjects for aging research. Therefore, biomedical researchers have employed different non-human organisms to study ovarian aging, including worms, fruit flies, fishes, amphibians, birds, mice, rats, cavies, rabbits, pigs, sheep, cows, horses, monkeys, and apes. Because each of these model organisms has its own features, multiple factors, such as size, anatomical structure, cost, ease of operation, fertility, generation time, lifespan, and gene heredity, should be carefully considered when selecting a model system to study ovarian aging. An appropriate model organism would help researchers explore the risk factors and elucidate molecular mechanisms underlying declined ovarian functions, which might be conducive to preventing or delaying the ovarian aging process. This article will offer an overview on several currently available and commonly used model organisms for ovarian aging research by comparing their pros and cons. In doing so, we hope to provide useful information for ovarian aging researchers.

Recent updates on animal models for understanding the etiopathogenesis of polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is the primary cause of female infertility affecting several women worldwide. Changes in hormonal functions such as hyperandrogenism are considered a significant factor in developing PCOS in women. In addition, many molecular pathways are involved in the pathogenesis of PCOS in women. To have better insights about PCOS, it is data from clinical studies carried on women suffering from PCOS should be collected. However, this approach has several implications, including ethical considerations, cost involved and availability of subject. Moreover, during the early drug development process, it is always advisable to use non-human models mimicking human physiology as they are less expensive, readily available, have a shorter gestation period and less risk involved. Many animal models have been reported that resemble the PCOS pathways in human subjects. However, the models developed on rats and mice are more preferred over other rodent/non-rodent models due to their closer resemblance with human PCOS development mechanism. The most extensively reported PCOS models for rats and mice include those induced by using testosterone, letrozole and estradiol valerate. As the pathophysiology of PCOS is complex, none of the explored models completely surrogates the PCOS related conditions occurring in women. Hence, there is a need to develop an animal model that can resemble the pathophysiology of PCOS in women. The review focuses on various animal models explored to understand the pathophysiology of PCOS. The article also highlights some environmental and food-related models that have been used to induce PCOS.

Polycystic Ovary Syndrome and Fibrocystic Breast Disease: An Updated Review

Polycystic ovary syndrome (PCOS) is the most common hormonal disorder in women of reproductive age. There is no clear association between PCOS and benign breast disease (BBD). The latter is a frequent benign disorder, affecting women between 20 and 50 years of age. To date, the classification remains controversial, and the risk of developing breast cancer that is associated with these changes is different depending on the histopathological findings. The most frequent changes are breast cysts, which are noted in up to 50% of patients older than 30 years of age. This up-to-date review presents the relationship between PCOS and BBD. In conclusion, there is no clear association between benign breast disease and PCOS. Further studies on a large population with prospectively collected data using updated PCOS criteria are necessary.

The polycystic ovary syndrome and gynecological cancer risk

This review updates the knowledge regarding the association between the polycystic ovary syndrome (PCOS) and the risk of gynecological cancer. We performed a literature review of clinical and epidemiological studies concerning PCOS and the risk of breast, endometrial and ovarian cancer after selecting information by quality of scientific methodology. It was found that evidence does not support a link between PCOS and breast cancer risk. There is an increased risk of endometrial cancer, while data concerning ovarian cancer are contradictory. Regarding PCOS and its association to cervical, fallopian tube, and vulvar cancer, the quality of evidence is heterogeneous. In conclusion, women with PCOS should be screened for endometrial cancer and more research is warranted to determine in this population the true risk of developing other gynecological cancers such as breast and ovarian.