Selective estrogen receptor modulators differentially regulate Alzheimer-like changes in female 3xTg-AD mice

Area of Science:

• Neuroscience
• Endocrinology
• Pharmacology

Background:

• Estrogen-based hormone therapy (HT) may reduce Alzheimer's disease (AD) risk but carries cancer concerns.
• Selective estrogen receptor modulators (SERMs) offer tissue-specific estrogenic effects, potentially minimizing risks.
• AD involves beta-amyloid (Abeta) accumulation and cognitive decline, particularly in postmenopausal women.

Purpose of the Study:

• To investigate the efficacy of SERMs, propylpyrazole triol (PPT) and diarylpropionitrile (DPN), in mitigating AD-like neuropathology.
• To assess SERM effects on Abeta accumulation and cognitive function in the 3xTg-AD mouse model.

Main Methods:

• Ovariectomized 3xTg-AD mice were treated with 17beta-estradiol (E2), PPT (ER-alpha selective), or DPN (ER-beta selective).
• Abeta protein levels in brain regions and hippocampal-dependent behavior were evaluated.
• Effects were compared to ovariectomy-induced hormone depletion and E2 treatment.

Main Results:

• Ovariectomy worsened Abeta accumulation and cognitive performance; E2 and PPT treatments ameliorated these effects.
• PPT reduced Abeta in hippocampus, subiculum, and amygdala, while DPN showed partial efficacy in frontal cortex and amygdala.
• PPT, but not DPN, improved behavioral performance, mimicking E2's effects.

Conclusions:

• SERMs, particularly PPT, demonstrate beneficial effects on AD neuropathology and behavior in a mouse model.
• These findings support further research into SERMs as a safer alternative to HT for AD risk reduction in postmenopausal women.