Functional adaptation of the maternal skeleton to reproduction and lactation
Department of Orthopaedic Surgery and Bioengineering
University of Pennsylvania
Abstract: The maternal skeleton serves as an important source of calcium for fetal/infant bone growth and undergoes substantial changes during pregnancy and lactation. Despite a substantial increase in bone formation following weaning, bone mass is only partially restored. However, most epidemiology studies report that the number of pregnancies and the duration of lactation have either no long-term adverse effect, or have a positive effect on fracture risk later in life. This represents a paradox that reproduction and lactation reduce bone mass without increasing future risk of fractures. To uncover the mechanisms behind this paradox, we compared the mechanical integrity between the highly load-bearing bone regions and other sites post-lactation, and demonstrated reduced bone loss and more efficient recovery in the load bearing vs. non-load bearing region. Furthermore, although post-lactation rats have lower bone mass than virgin rats, they have a distinct bone structural phenotype and a much slower rate of bone loss when exposed to estrogen deficiency by ovariectomy (OVX). These discoveries suggested that skeletal changes that occur during reproduction and lactation represent a physiological adaptation of bone structure, which minimizes the impact of reproduction on the skeleton’s mechanical function and prepares the skeleton to be more resistant to estrogen deficiency induced bone loss later in life. These amazing adaptive mechanisms in bone may help to protect the maternal skeleton from future menopausal bone loss.
Room 132 of the Business and Science Bldg.
Date & Time
January 26, 2016
12:20 pm-1:20 pm