Chronic hyperglycemia and the human fetal beta cell

Area of Science:

• Endocrinology
• Developmental Biology
• Pancreatic Islet Research

Background:

• Immature rodent fetal beta cells enhance insulin release after chronic high glucose exposure in vitro.
• Human infants of diabetic mothers exhibit more mature insulin release patterns.

Purpose of the Study:

• To investigate if human fetal beta cells mature similarly to rodent cells when exposed to high glucose concentrations in vitro.
• To assess the impact of chronic glucose exposure on human fetal pancreatic explant function.

Main Methods:

• Organ culture of human fetal pancreatic explants.
• Exposure to varying glucose concentrations (0-30 mM) for six weeks.
• Assessment of insulin release, proinsulin levels, insulin content, and response to theophylline.

Main Results:

• Chronic exposure to high glucose (up to 30 mM) did not enhance the acute insulin response to glucose in human fetal explants.
• Chronic insulin release was enhanced, but similarly at 2.8 mM and 30 mM glucose.
• Insulin content increased in explants cultured with 5.6-30 mM glucose, but not 2.8 mM.
• Rat fetal pancreatic explants showed maturation with 11.2 mM glucose exposure.

Conclusions:

• Human fetal beta cells show limited in vitro maturation in response to high glucose compared to rodent models.
• Chronic glucose exposure affects basal insulin release and content but not acute glucose-stimulated insulin secretion in human fetal pancreatic tissue.
• Findings suggest species-specific differences in fetal beta cell maturation pathways.