Estrogen deficiency heterogeneously affects tissue specific stem cells in mice.

Area of Science:

• Reproductive biology
• Stem cell biology
• Endocrinology

Background:

• Postmenopausal disorders are common but their link to estrogen deficiency and underlying mechanisms are not fully understood.
• Tissue-specific stem cells express estrogen receptors, suggesting a potential role in estrogen-related disorders.

Purpose of the Study:

• To investigate the hypothesis that estrogen deficiency impairs tissue-specific stem cells, contributing to postmenopausal disorders.
• To examine the effects of ovariectomy and estrogen replacement on hematopoietic, mesenchymal, and satellite stem cells in mice.

Main Methods:

• Ovariectomy was performed on six-week-old C57BL/6 female mice.
• Mice received 17β-estradiol replacement or vehicle (control); sham-operated mice served as healthy controls.
• Stem cell populations (c-kit+, CD105+, Pax7+) and their function were evaluated two months post-treatment.

Main Results:

• Ovariectomy decreased uterine weight, partially restored by estrogen replacement.
• Ovariectomy increased c-kit-positive hematopoietic stem/progenitor cells but impaired their colony-forming capacity; estrogen replacement further increased cell numbers without improving function.
• CD105-positive mesenchymal stem cells decreased after ovariectomy, fully recovering with estrogen replacement.
• Pax7-positive satellite cells remained unchanged by ovariectomy or estrogen treatment.

Conclusions:

• Estrogen deficiency heterogeneously affects tissue-specific stem cells, impacting hematopoietic and mesenchymal stem cells.
• These stem cell alterations suggest a direct relationship between estrogen deficiency and the development of postmenopausal disorders.