Gestational hyperglycemia reprograms cardiac gene expression in rat offspring.

Area of Science:

• Developmental biology
• Cardiovascular physiology
• Endocrinology

Background:

• Maternal pregestational hyperglycemia induces cardiac dysfunction and altered gene expression in developing rat fetuses.
• These cardiac abnormalities in fetuses near term suggest potential long-term consequences for offspring health.

Purpose of the Study:

• To investigate the transient nature of cardiac gene expression and morphological changes in offspring exposed to maternal hyperglycemia.
• To determine if cardiac abnormalities normalize after birth or persist into postnatal life.

Main Methods:

• Induction of maternal hyperglycemia in rats using streptozotocin.
• Collection and analysis of offspring hearts at postnatal days 0, 7, and 14 for histology and gene expression.
• Comparison of gene expression profiles related to cardiac contractility, growth, and metabolism between hyperglycemia-exposed and control offspring.

Main Results:

• At postnatal day 0, offspring of hyperglycemic dams exhibited increased heart weight and decreased expression of key cardiac genes.
• By postnatal day 7, most gene expression changes normalized, despite increased cardiomyocyte apoptosis.
• Abnormalities in the expression of genes crucial for myocardial growth, function, and metabolism recurred by postnatal day 14.

Conclusions:

• Cardiac gene expression abnormalities in offspring of hyperglycemic rats are largely transient during the first week of life.
• However, by postnatal day 14, significant alterations in genes vital for cardiac growth, function, and metabolism re-emerge.
• These findings highlight a critical window of vulnerability and potential for lasting cardiac impact despite initial normalization.