Brain substrate metabolism and ß-cell function in humans: A positron emission tomography study

Area of Science:

• Neuroscience
• Endocrinology
• Metabolic Research

Background:

• Recent studies indicate altered brain glucose and fatty acid uptake in insulin resistance.
• Preclinical data suggests the brain influences insulin secretion.

Purpose of the Study:

• To investigate the association between brain metabolism (glucose and fatty acid uptake) and human beta-cell function parameters.

Main Methods:

• Cross-sectional analysis of 120 subjects with varying BMI and insulin sensitivity.
• Brain glucose uptake (BGU) measured via [18F]-fluorodeoxyglucose (FDG) PET during clamp or fasting.
• Brain fatty acid uptake measured via [18F]-fluoro-6-thia-heptadecanoic acid (FTHA) PET.
• Beta-cell function parameters derived from oral glucose tolerance test (OGTT) modeling.

Main Results:

• In non-diabetics, BGU during clamp positively correlated with basal insulin secretion rate and total insulin output.
• Brain fatty acid uptake during fasting correlated positively with basal insulin secretion rate in non-diabetics.
• Associations were independent of BMI and whole-body insulin sensitivity in non-diabetics.

Conclusions:

• Provides correlative evidence for the brain's involvement in controlling human insulin secretion.
• Suggests a potential role for brain metabolism in regulating beta-cell function, independent of insulin sensitivity.