Collagen and elastic fiber remodeling in the pregnant mouse myometrium†.

The myometrium undergoes progressive tissue remodeling from early to late pregnancy to support fetal growth and transitions to the contractile phase to deliver a baby at term. Much of our effort has been focused on understanding the functional role of myometrial smooth muscle cells, but the role of extracellular matrix is not clear. This study was aimed to demonstrate the expression profile of sub-sets of genes involved in the synthesis, processing, and assembly of collagen and elastic fibers, their structural remodeling during pregnancy, and hormonal regulation. Myometrial tissues were isolated from non-pregnant and pregnant mice to analyze gene expression and protein levels of components of collagen and elastic fibers. Second harmonic generation imaging was used to examine the morphology of collagen and elastic fibers. Gene and protein expressions of collagen and elastin were induced very early in pregnancy. Further, the gene expressions of some of the factors involved in the synthesis, processing, and assembly of collagen and elastic fibers were differentially expressed in the pregnant mouse myometrium. Our imaging analysis demonstrated that the collagen and elastic fibers undergo structural reorganization from early to late pregnancy. Collagen and elastin were differentially induced in response to estrogen and progesterone in the myometrium of ovariectomized mice. Collagen was induced by both estrogen and progesterone. By contrast, estrogen induced elastin, but progesterone suppressed its expression. The current study suggests progressive extracellular matrix remodeling and its potential role in the myometrial tissue mechanical function during pregnancy and parturition.

Different and Unequal: A Qualitative Evaluation of Salient Factors Influencing Energy Intake in Adults with Overweight and Obesity.

Environmental factors such as food availability and variety can function as cues for overeating in individuals susceptible to overweight or obesity, but relatively little is known about other types of environmental factors that may also be important. This qualitative study compared and contrasted categories of internal and external cues through focus groups and key informant interviews with 24 adults (26 to 77 years old) in the United States who had a body mass index within the healthy range (21.6 ± 2.5 kg/m2) or had overweight or obesity (29.1 ± 3.6 kg/m2). Five domains of external factors influencing food intake were identified: (a) Environmental cues including food availability and variety; (b) normative expectations for dietary intake; (c) food palatability; (d) overt social pressures to overeat; and (e) perceived social expectations around eating. All external domains were noted by participants with overweight or obesity to be challenging, and solutions to avoid overeating were lacking; however, overt social pressures and perceived social expectations appeared to be especially problematic. By explicitly defining different domains of external factors that challenge healthy weight regulation, this study identifies specific targets to address in interventions for healthy weight management.