Physiological changes in circulating mannose levels in normal, glucose-intolerant, and diabetic subjects

Area of Science:

• Biochemistry
• Endocrinology
• Clinical Diagnostics

Background:

• Mannose is a vital hexose for glycoprotein synthesis.
• Circulating mannose levels are affected by metabolic disorders, but physiological fluctuations in normal and diabetic individuals are poorly understood.
• Accurate measurement of plasma mannose is crucial for understanding its role in glucose metabolism.

Purpose of the Study:

• To develop and validate a sensitive assay for measuring circulating mannose levels.
• To investigate the correlation between plasma mannose and glucose levels in normal and diabetic subjects.
• To evaluate the potential of plasma mannose as a supplementary diagnostic marker for diabetes.

Main Methods:

• Development of a new sensitive assay for plasma mannose.
• Measurement of plasma mannose levels in 273 normal and diabetic subjects.
• Correlation analysis between plasma mannose, fasting plasma glucose, and response to oral glucose tolerance tests.

Main Results:

• A strong correlation (r = 0.754) was observed between fasting plasma mannose (FPM) and fasting plasma glucose (FPG).
• The mannose assay demonstrated sensitivity and specificity comparable to HbA(1c) for impaired glucose tolerance and diabetes with normal FPG.
• Plasma mannose levels fluctuated less than glucose levels during an oral glucose tolerance test and after meals, correlating better with daily glucose variability.

Conclusions:

• Plasma mannose levels closely correlate with fasting plasma glucose levels.
• The assay's ability to detect subtle changes suggests potential for supplementary diagnosis of mild diabetes.
• Mannose measurement may offer a novel approach for diabetes screening and monitoring.