Remodeling of Myocardial Collagen in Domestic Cattle during Pregnancy and Postpartum

Abstract

Pregnancy is a blood volume overload state accompanied by functional cardiac hypertrophy. Interestingly, cardiac remodeling in pregnancy is distinct in its absence of myocardial fibrosis, which is a common characteristic of pathological cardiac hypertrophy. The objective of this study was to characterize myocardial remodeling throughout pregnancy & post-partum in domestic cattle. The results identified mechanical adaptations of the myocardium during pregnancy – significant increases in UTS and extensibility. Accompanying those transformations were reductions in myocardial collagen thermal stability and mature crosslinking. Together, myocardial remodeling in pregnancy is a functional process allowing the myocardium to expand to accommodate blood volume overload, without compromising structural-mechanical integrity. This work has shown for the first time, pregnancy-induced myocardial collagen remodeling in cows. Importantly, this study suggests that myocardial remodeling leads to a permanent loosening of the myocardial collagen network in postpartum, with a persistent increase in extensibility and replacement of mature with immature collagen crosslinks.