title: Hyperglycemia slows embryonic growth and suppresses cell cycle via cyclin D1 and p21.
abstract: In pregnant women, the diabetic condition results in a three- to fivefold increased risk for fetal cardiac malformations as a result of elevated glucose concentrations and the resultant osmotic stress in the developing embryo and fetus. Heart development before septation in the chick embryo was studied under two hyperglycemic conditions. Pulsed hyperglycemia induced by daily administration of glucose during 3 days of development caused daily spikes in plasma glucose concentration. In a second model, sustained hyperglycemia was induced with a single injection of glucose into the yolk on day 0. The sustained model raised the average plasma glucose concentration from 70 mg/dL to 180 mg/dL and led to decreased gene expression of glucose transporter GLUT1. Both models of hyperglycemia reduced embryo size, increased mortality, and delayed development. Within the heart outflow tract, reduced proliferation of myocardial and endocardial cells resulted from the sustained hyperglycemia and hyperosmolarity. The cell cycle inhibitor p21 was significantly increased, whereas cyclin D1, a cell cycle promoter, decreased in sustained hyperglycemia compared with controls. The evidence suggests that hyperglycemia-induced developmental delays are associated with slowed cell cycle progression, leading to reduced cellular proliferation. The suppression of critical developmental steps may underlie the cardiac defects observed during late gestation under hyperglycemic conditions.
authors.affiliation: Biomedical Engineering Department, Oregon Health & Science University, Portland, Oregon, USA.
authors.forename: Devon E
authors.initials: DE
authors.lastname: Scott-Drechsel
authors.forename: Sandra
authors.initials: S
authors.lastname: Rugonyi
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Marks
authors.forename: Kent L
authors.initials: KL
authors.lastname: Thornburg
authors.forename: Monica T
authors.initials: MT
authors.lastname: Hinds
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002453:Cell Cycle; D049109:Cell Proliferation; D002642:Chick Embryo; D019938:Cyclin D1 / Q000502:physiology*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000502:physiology*; D047108:Embryonic Development; D005260:Female; D051272:Glucose Transporter Type 1 / Q000502:physiology; D006330:Heart Defects, Congenital / Q000209:etiology; D006801:Humans; D006943:Hyperglycemia / Q000503:physiopathology*; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000503:physiopathology
chemical_list: D001786:Blood Glucose; D050759:Cyclin-Dependent Kinase Inhibitor p21; D051272:Glucose Transporter Type 1; D019938:Cyclin D1