Overexpression of the SK3 channel alters vascular remodeling during pregnancy, leading to fetal demise.
The maternal cardiovascular system undergoes hemodynamic changes during pregnancy via angiogenesis and vasodilation to ensure adequate perfusion of the placenta. Improper vascularization at the maternal-fetal interface can cause pregnancy complications and poor fetal outcomes. Recent evidence indicates that small conductance Ca(2+)-activated K(+) channel subtype 3 (SK3) contributes to vascular remodeling during pregnancy, and we hypothesized that abnormal SK3 channel expression would alter the ability of the maternal cardiovascular system to adapt to pregnancy demands and lead to poor fetal outcomes. We investigated this hypothesis using transgenic Kcnn3(tm1Jpad)/Kcnn3(tm1Jpad) (SK3(T/T)) mice that overexpress the channel. Isolated pressurized uterine arteries from nonpregnant transgenic SK3(T/T) mice had larger basal diameters and decreased agonist-induced constriction than those from their wild-type counterparts; however, non-receptor-mediated depolarization remained intact. In addition to vascular changes, heart rates and ejection fraction were increased, whereas end systolic volume was reduced in SK3(T/T) mice compared with their wild-type littermates. Uterine sonography of the fetuses on pregnancy day 14 showed a significant decrease in fetal size in SK3(T/T) compared with wild-type mice; thus, SK3(T/T) mice displayed an intrauterine growth-restricted phenotype. The SK3(T/T) mice showed decreased placental thicknesses and higher incidence of fetal loss, losing over half of their complement of pups by midgestation. These results establish that the SK3 channel contributes to both maternal and fetal outcomes during pregnancy and point to the importance of SK3 channel regulation in maintaining a healthy pregnancy.
Department of Obstetrics and Gynecology, Washington Univ. School of Medicine, St. Louis, MO 63110, USA.
Cara C
CC
Rada
Stephanie L
SL
Pierce
Daniel W
DW
Nuno
Kathy
K
Zimmerman
Kathryn G
KG
Lamping
Noelle C
NC
Bowdler
Robert M
RM
Weiss
Sarah K
SK
England
D000818:Animals; D005260:Female; D005313:Fetal Death / Q000235:genetics / Q000378:metabolism*; D005317:Fetal Growth Retardation / Q000235:genetics / Q000378:metabolism*; D006339:Heart Rate / Q000235:genetics / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009929:Organ Size; D010920:Placenta / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D011247:Pregnancy; D051640:Small-Conductance Calcium-Activated Potassium Channels / Q000096:biosynthesis* / Q000235:genetics; D013318:Stroke Volume / Q000235:genetics / Q000502:physiology; D016216:Ultrasonography, Prenatal / Q000379:methods; D055988:Uterine Artery / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D014599:Uterus / Q000098:blood supply / Q000000981:diagnostic imaging
C496900:Kcnn3 protein, mouse; D051640:Small-Conductance Calcium-Activated Potassium Channels