Congenital heart defects (CHDs) represent the most common form of human birth defects; approximately one-third of heart defects involve malformations of the outflow tract (OFT). Maternal diabetes increases the risk of CHD by 3-5 fold. During heart organogenesis, little is known about the effects of hyperglycemia on hemodynamics, which are critical to normal heart development. Heart development prior to septation in the chick embryo was studied under hyperglycemic conditions. Sustained hyperglycemic conditions were induced, raising the average plasma glucose concentration from 70 mg/dL to 180 mg/dL, akin to the fasting plasma glucose of a patient with diabetes. The OFTs were assessed for structural and hemodynamic alterations using optical coherence tomography (OCT), confocal microscopy, and microcomputed tomography. In hyperglycemic embryos, the endocardial cushions of the proximal OFT were asymmetric, and the OFTs curvature and torsion were significantly altered. The blood flow velocity through the OFT of hyperglycemic embryos was significantly decreased, including flow reversal in 30% of the cardiac cycle. Thus, hyperglycemia at the onset of gestation results in asymmetric proximal endocardial cushions, abnormal OFT curvature...Continue Reading
Birth defects encompass structural and functional alterations that occur during embryonic or fetal development and are present since birth. The cause may be genetic, environmental or unknown and can result in physical and/or mental impairment. Here is the latest research on birth defects.