Hemodynamic Forces Regulate Collagen Deposition in the Embryonic Chicken Outflow Tract

Alterations in blood flow at early embryonic stages can lead to detrimental remodeling and heart defects, but these structural adaptations are not well understood. We hypothesize that deposition of collagens will be increased as shear stress is increased — leading to a stiffer wall. To test this hypothesis a suture (OTB) was tightened around the outflow tract (OFT) of stage HH18 chick embryos for 24 hours to reduce cross sectional area of the lumen. Sham and OTB embryos were immunostained for collagen I, III, VI and XIV, imaged with confocal microscopy, and staining was quantified by grayscale analysis. Changes in fibril collagens I and III were not observed, however deposition of collagens VI and XIV increased in a degree-of-constriction dependent manner. The observed increase in collagen VI and XIV deposition suggests they play a key role in structural adaptation to increased hemodynamic pressure.